This document provides an overview of bacterial anatomy, physiology, growth, nutrition, metabolism, toxins, and bacteriocins. It describes the structure and functions of bacterial cell organelles such as the cell wall, plasma membrane, mesosomes, nucleoid, plasmids, ribosomes, inclusion bodies, and endospores. It compares the cell walls of gram-positive and gram-negative bacteria and discusses bacterial movement of molecules, metabolism, and sporulation. The document is an educational reference on basic microbiology.
Negative staining allows visualization of bacterial cell morphology without directly staining the cells. It works by using acidic stains like India ink or nigrosin that stain the background glass slide rather than the negatively charged bacterial cells. This occurs because the stain is negatively charged and repelled from the bacterial surface. Negative staining provides clear views of cell shape and arrangement against a dark background without requiring heat fixation, making it useful for delicate cells. It involves mixing a bacterial culture with the negative stain to form a thin smear on a slide for examination under a microscope.
This document summarizes the structure of bacterial cells. It describes the key components including the cell wall, plasma membrane, and intracellular and extracellular structures. The cell wall differs between gram-positive and gram-negative bacteria. Gram-positive walls are thicker and contain higher amounts of peptidoglycan while gram-negative walls are thinner and contain an outer lipopolysaccharide membrane. Intracellular structures discussed include the nucleoid, ribosomes, plasmids, and mesosomes. Extracellular structures include flagella, pili, and capsules. Bacteria range in size from 0.4 to 1.5 micrometers and have characteristic shapes including cocci, bacilli, spirilla and spirochetes.
The bacterial flagellum has three main parts - the filament, basal body, and hook. The filament is the longest, rigid structure made of the protein flagellin. The basal body is embedded in the cell and contains protein rings. The hook connects the filament to the basal body. The basal body contains protein rings and a central rod that span the cell membranes. Rotation of the flagellum is driven by a motor composed of a rotor and stator. Proton motive force powers the motor and causes clockwise or counter-clockwise rotation for movement or tumbling.
Staphylococci are spherical bacteria that occur in grape-like clusters. Staphylococcus aureus is an important human pathogen that can cause a variety of infections, from minor skin infections to life-threatening conditions like toxic shock syndrome and endocarditis. S. aureus produces several virulence factors like toxins and enzymes that damage tissues and evade the immune system. Laboratory diagnosis involves culture, microscopy, and tests like coagulase to identify S. aureus. Antibiotics are used to treat infections, and prevention focuses on hygiene and safe food handling. Methicillin-resistant S. aureus is an antibiotic resistant form that is more difficult to treat.
Bacterial capsules are gelatinous envelopes that surround bacterial cells and are usually polysaccharide or polypeptide in nature. Capsules contribute to virulence in pathogenic bacteria by making the cells more resistant to phagocytosis. Capsulated bacteria form distinct colony morphologies compared to unencapsulated bacteria. Examples of bacteria that produce capsules include Streptococcus pneumoniae, Klebsiella, Haemophilus influenzae, Neisseria meningitidis, and Pseudomonas aeruginosa. Capsules protect bacteria by attaching to surfaces, protecting from phagocytosis, and providing resistance to environmental stresses.
This document discusses immunity and antigen-antibody reactions. It begins with definitions of immunity, antigens, and antibodies. It describes the components of the immune system including antigen specificity and types of antigens. It then explains antigen-antibody reactions and how they are used for diagnostic tests. Different diagnostic tests are also summarized, including precipitation reactions, agglutination, immunofluorescence, radioimmunoassay, and ELISA. Potential sources of markers for periodontal disease activity are also listed.
This document provides an introduction to bacteria prepared by Raghdah Abdulsalam Malibari for her microbiology course at King Abdulaziz University in 2012-2013. It defines bacteria as single-celled microscopic organisms that lack nuclei. The document describes bacterial shapes, sizes, where they are found, and their structures including flagella, capsule, plasma membrane, chromosome or plasmid, cytoplasm, ribosomes, and cell wall. It explains the functions of these structures in protein production, movement, attachment, protection, and maintaining cell shape.
Negative staining allows visualization of bacterial cell morphology without directly staining the cells. It works by using acidic stains like India ink or nigrosin that stain the background glass slide rather than the negatively charged bacterial cells. This occurs because the stain is negatively charged and repelled from the bacterial surface. Negative staining provides clear views of cell shape and arrangement against a dark background without requiring heat fixation, making it useful for delicate cells. It involves mixing a bacterial culture with the negative stain to form a thin smear on a slide for examination under a microscope.
This document summarizes the structure of bacterial cells. It describes the key components including the cell wall, plasma membrane, and intracellular and extracellular structures. The cell wall differs between gram-positive and gram-negative bacteria. Gram-positive walls are thicker and contain higher amounts of peptidoglycan while gram-negative walls are thinner and contain an outer lipopolysaccharide membrane. Intracellular structures discussed include the nucleoid, ribosomes, plasmids, and mesosomes. Extracellular structures include flagella, pili, and capsules. Bacteria range in size from 0.4 to 1.5 micrometers and have characteristic shapes including cocci, bacilli, spirilla and spirochetes.
The bacterial flagellum has three main parts - the filament, basal body, and hook. The filament is the longest, rigid structure made of the protein flagellin. The basal body is embedded in the cell and contains protein rings. The hook connects the filament to the basal body. The basal body contains protein rings and a central rod that span the cell membranes. Rotation of the flagellum is driven by a motor composed of a rotor and stator. Proton motive force powers the motor and causes clockwise or counter-clockwise rotation for movement or tumbling.
Staphylococci are spherical bacteria that occur in grape-like clusters. Staphylococcus aureus is an important human pathogen that can cause a variety of infections, from minor skin infections to life-threatening conditions like toxic shock syndrome and endocarditis. S. aureus produces several virulence factors like toxins and enzymes that damage tissues and evade the immune system. Laboratory diagnosis involves culture, microscopy, and tests like coagulase to identify S. aureus. Antibiotics are used to treat infections, and prevention focuses on hygiene and safe food handling. Methicillin-resistant S. aureus is an antibiotic resistant form that is more difficult to treat.
Bacterial capsules are gelatinous envelopes that surround bacterial cells and are usually polysaccharide or polypeptide in nature. Capsules contribute to virulence in pathogenic bacteria by making the cells more resistant to phagocytosis. Capsulated bacteria form distinct colony morphologies compared to unencapsulated bacteria. Examples of bacteria that produce capsules include Streptococcus pneumoniae, Klebsiella, Haemophilus influenzae, Neisseria meningitidis, and Pseudomonas aeruginosa. Capsules protect bacteria by attaching to surfaces, protecting from phagocytosis, and providing resistance to environmental stresses.
This document discusses immunity and antigen-antibody reactions. It begins with definitions of immunity, antigens, and antibodies. It describes the components of the immune system including antigen specificity and types of antigens. It then explains antigen-antibody reactions and how they are used for diagnostic tests. Different diagnostic tests are also summarized, including precipitation reactions, agglutination, immunofluorescence, radioimmunoassay, and ELISA. Potential sources of markers for periodontal disease activity are also listed.
This document provides an introduction to bacteria prepared by Raghdah Abdulsalam Malibari for her microbiology course at King Abdulaziz University in 2012-2013. It defines bacteria as single-celled microscopic organisms that lack nuclei. The document describes bacterial shapes, sizes, where they are found, and their structures including flagella, capsule, plasma membrane, chromosome or plasmid, cytoplasm, ribosomes, and cell wall. It explains the functions of these structures in protein production, movement, attachment, protection, and maintaining cell shape.
Medical microbiology is the study of microbes like bacteria, viruses, fungi and parasites that cause human illness and disease. A medical microbiologist studies the characteristics of pathogens, their transmission, mechanisms of infection and growth. The field primarily focuses on the presence and growth of microbial infections in individuals, their effects on the human body, and treatment methods. Some key areas of study include microbial physiology, genetics, parasitology, virology, immunology and serology.
Culture medium or growth medium is a liquid or gel designed to support the growth of microorganisms. There are different types of media suitable for growing different types of cells. Here, we will discuss microbiological cultures used for growing microbes, such as bacteria ,fungi, yeast & algae.
Bacteria have a simple structure compared to eukaryotic cells, lacking organelles. Their small size allows rapid growth and inhabitation of diverse environments. Bacterial cells contain a cytoplasm surrounded by a cell membrane and cell wall. The cytoplasm holds the circular chromosome, ribosomes for protein production, and storage structures. Some bacteria have flagella for mobility or pili for attachment. Gram-positive bacteria have a thick peptidoglycan cell wall, while Gram-negatives have a thin wall and an outer membrane. This membrane structure contributes to differences in antibiotic susceptibility between Gram-positive and Gram-negative bacteria.
The bacterial cell wall lies outside the cell membrane and provides several key functions for the cell. In gram-positive bacteria, the cell wall is thick and largely composed of peptidoglycan, while in gram-negative bacteria it is thinner with an additional outer membrane. Peptidoglycan is a polymer mesh made of sugars and amino acids that maintains cell shape and integrity. The structures and components of the cell wall help determine how the cell will interact with its environment and respond to antibiotics.
This document discusses normal flora and its relationship to the human body. It defines normal flora as microorganisms commonly found on and inside the human body. These microbes exist in either mutualistic, commensal, or opportunistic relationships with their human hosts. The document outlines several types of normal flora, including resident flora that always live on the body and transient flora that only remain for short periods. It also explains how normal flora can protect the body but also potentially cause disease.
The document discusses the antigen-antibody system. It defines antigen and antibody, and describes how they interact specifically. It explains different types of antigen-antibody reactions like precipitation, agglutination, neutralization, immunofluorescence, ELISA, and immunoelectron microscopy. These reactions form the basis of immunity and are used for disease diagnosis, identification of bacteria and viruses, forensic applications, and more. The antigen-antibody system plays an important role in both preventing and diagnosing infectious diseases.
This document discusses various staining techniques used to visualize bacteria under a microscope. It covers simple staining techniques like Gram staining and acid-fast staining, as well as methods to identify specific structures like volutin granules and bacterial spores. Gram staining uses dyes to differentiate between Gram-positive and Gram-negative bacteria based on their cell wall composition. Acid-fast staining targets bacteria with thick lipid cell walls like Mycobacterium tuberculosis. Specialized techniques employ unique dyes and fixation steps to highlight intracellular inclusions and endospores. Proper staining is crucial for bacterial identification and clinical diagnosis.
Normal flora, including bacteria, fungi and viruses, colonize various sites of the human body through mutualistic and commensal relationships. Microbiota commonly reside on the skin, in the mouth, respiratory tract, gastrointestinal tract, eyes, and genital region through tissue specificity involving bacterial adherence and biofilm formation preferential for certain tissues. While generally beneficial, microbiota can become pathogenic under conditions like immunosuppression or change in location. References included Medical Microbiology and Jawetz Melnick & Adelbergs Medical Microbiology textbooks.
1. Bacteria are unicellular prokaryotes that vary in size from 0.5-10 micrometers. They have distinct cell shapes including cocci, bacilli, spirilla, and vibrios.
2. The bacterial cell contains a cell membrane, cell wall, cytoplasm, and varying structures like flagella, pili, capsules, and endospores. The cell wall structure differs between gram positive and gram negative bacteria.
3. Gram staining allows bacteria to be classified as either gram positive or gram negative based on differences in their cell wall structures. Specialized structures like flagella, pili and capsules serve functions like motility, adhesion and virulence.
Direct microscopic examination of clinical specimens can provide a presumptive diagnosis of fungal infection by revealing the presence of fungal elements. Different stains and techniques are used to visualize fungi depending on the suspected infection. KOH wet mounts are useful for superficial mycoses while GMS, H&E and fluorescent antibody stains aid in diagnosis of deep mycoses from tissue biopsies and body fluids. Proper specimen collection and rapid microscopic evaluation can help initiate appropriate antifungal treatment.
Giving basic concepts regarding culture media and its classification on the basis of different properties like physical state, chemical composition and utility purposes.
This document discusses antibiotic sensitivity testing (AST), which determines how effective antibiotics are against bacteria in vitro. AST is important for selecting the best antibiotic treatment for patients, monitoring antibiotic resistance trends, and accumulating epidemiological data. The Kirby-Bauer disk diffusion method is described, which uses antibiotic-impregnated disks placed on agar plates inoculated with bacteria. The diameter of inhibition zones around the disks after incubation indicates antibiotic sensitivity. Interpretive criteria classify results as sensitive, intermediate, or resistant. AST provides guidance for clinicians in choosing effective antibiotic therapy.
Pure cultures are important in microbiology because they allow for the accurate study and identification of microorganisms. There are three main techniques involved in obtaining a pure culture: sterilization of materials to prevent contamination, aseptic transfer of microbes to growth media, and isolating single cells or their progeny. Some common isolation methods are streak plating, spread plating, and serial dilution plating. Once a pure culture is obtained, its purity can be demonstrated by the uniform appearance of colonies and identical growth characteristics of isolated colonies. Pure cultures must then be maintained through refrigeration, paraffin coating, cryopreservation, or lyophilization to preserve them for long-term storage and future use.
The normal flora are microorganisms that commonly live on and inside the healthy human body in different areas without causing issues. They can be divided into transient microbes that vary over time and resident microbes that persist. The types of microbes vary by body site, such as Staphylococcus and Streptococcus on the skin, Streptococcus and anaerobes in the mouth, and a diverse array of bacteria including E. coli in the large intestine. The composition of the normal flora is influenced by factors like age, hygiene, and diet.
The document discusses three methods for isolating pure cultures of microbes: streak plate technique, pour plate technique, and spread plate technique. The streak plate technique involves spreading microbial culture on media with a sterilized inoculating needle. The pour plate technique mixes culture with liquid agar before pouring into plates, trapping some microbes beneath the surface. The spread plate technique spreads diluted culture samples on the agar surface and is best for isolating pure colonies as it only produces surface colonies.
This document discusses antigens and their classification. It defines antigens as substances that can induce an immune response. Antigens are classified as either exogenous (external) or endogenous (internal) antigens. Exogenous antigens enter the body from the external environment, while endogenous antigens are further divided into xeno-genic, allogenic, and autologous antigens based on their origin. The document also discusses the properties of immunogens and antigens, as well as factors that contribute to immunogenicity.
The document outlines the classification and characteristics of medically important parasites. It discusses the classification of parasites into helminths (trematodes, cestodes, nematodes) and protozoa. For each type of parasite, it describes morphological features, life cycles, important stages, habitats, and modes of infection. The objectives are to differentiate parasite types based on these characteristics and list examples of medically significant parasites.
This document discusses various ways that bacteria can be classified, including phenotypic and genotypic classification. Phenotypically, bacteria are classified based on their morphology, anatomy, staining characteristics, culture growth, nutritional requirements, and environmental tolerances. Morphologically, bacteria are classified as cocci, bacilli, actinomycetes, spirochetes, mycoplasmas, or rickettsiae/chlamydiae depending on their shape and arrangement. Anatomical features used in classification include whether they have capsules, flagella, spores, and their gram stain reaction.
The document discusses various methods for diagnosing important bacterial diseases through laboratory examination. Effective diagnosis allows for timely treatment and control measures. Key methods discussed include microscopy, culture techniques, biochemical reactions, serological identification, and molecular diagnosis. Microscopy can identify bacterial morphology and staining properties. Culture techniques isolate bacteria on selective media and examine colony characteristics. Biochemical tests identify metabolic properties. Serology detects bacterial antigens and antibodies. Molecular methods like PCR and sequencing provide sensitive, specific identification and can detect non-culturable bacteria. Together, these diagnostic methods allow clinicians to initiate appropriate treatment and control of bacterial outbreaks.
This document provides an overview of bacterial anatomy, physiology, growth, nutrition, metabolism, toxins, and bacteriocins. It begins with an outline of the topics to be covered, including the structure and function of bacterial cell organelles, growth and nutrition, metabolism, toxins, and bacteriocins. The document then discusses the structure of the bacterial cell and its various components such as the cell wall, plasma membrane, mesosomes, nucleoid, plasmids, ribosomes, inclusion bodies, and endospores. It provides details on the cell wall structure of gram-positive and gram-negative bacteria. The document also covers bacterial metabolism, toxins, and bacteriocins.
Bacteria- Bacteria, the oldest and most diversified creatures on our planet, have a structure that is both basic and interesting.
Key points-
cell envelope- Investigate the bacterial cell's outermost layers, including the cell wall, cell membrane, and any other components that defend and preserve cell integrity.
cytoplasm and nucleotide- Discover the inner workings of bacterial cells, where genetic material is stored, metabolism occurs, and critical functions are organised.
Appandages and Flagella-Learn about the many appendages that bacteria can have, such as flagella, pili, and fimbriae, and how they help in motility and adherence.
Inclusions and Granules:Learn how bacteria adapt to their surroundings by storing energy and critical chemicals in the form of inclusions and granules.
Structural variation-Explore the variety of bacterial structure across various species and how these changes contribute to their adaptation and success.
Interactions and Ecological Importance: Investigate how bacteria's structure effects their interactions with other species and their significance in ecosystems.
This slide is presented by
Deepti Negi
Assistant professor
Pharmacology
Shri Guru Ram Rai University
Dehradun
Medical microbiology is the study of microbes like bacteria, viruses, fungi and parasites that cause human illness and disease. A medical microbiologist studies the characteristics of pathogens, their transmission, mechanisms of infection and growth. The field primarily focuses on the presence and growth of microbial infections in individuals, their effects on the human body, and treatment methods. Some key areas of study include microbial physiology, genetics, parasitology, virology, immunology and serology.
Culture medium or growth medium is a liquid or gel designed to support the growth of microorganisms. There are different types of media suitable for growing different types of cells. Here, we will discuss microbiological cultures used for growing microbes, such as bacteria ,fungi, yeast & algae.
Bacteria have a simple structure compared to eukaryotic cells, lacking organelles. Their small size allows rapid growth and inhabitation of diverse environments. Bacterial cells contain a cytoplasm surrounded by a cell membrane and cell wall. The cytoplasm holds the circular chromosome, ribosomes for protein production, and storage structures. Some bacteria have flagella for mobility or pili for attachment. Gram-positive bacteria have a thick peptidoglycan cell wall, while Gram-negatives have a thin wall and an outer membrane. This membrane structure contributes to differences in antibiotic susceptibility between Gram-positive and Gram-negative bacteria.
The bacterial cell wall lies outside the cell membrane and provides several key functions for the cell. In gram-positive bacteria, the cell wall is thick and largely composed of peptidoglycan, while in gram-negative bacteria it is thinner with an additional outer membrane. Peptidoglycan is a polymer mesh made of sugars and amino acids that maintains cell shape and integrity. The structures and components of the cell wall help determine how the cell will interact with its environment and respond to antibiotics.
This document discusses normal flora and its relationship to the human body. It defines normal flora as microorganisms commonly found on and inside the human body. These microbes exist in either mutualistic, commensal, or opportunistic relationships with their human hosts. The document outlines several types of normal flora, including resident flora that always live on the body and transient flora that only remain for short periods. It also explains how normal flora can protect the body but also potentially cause disease.
The document discusses the antigen-antibody system. It defines antigen and antibody, and describes how they interact specifically. It explains different types of antigen-antibody reactions like precipitation, agglutination, neutralization, immunofluorescence, ELISA, and immunoelectron microscopy. These reactions form the basis of immunity and are used for disease diagnosis, identification of bacteria and viruses, forensic applications, and more. The antigen-antibody system plays an important role in both preventing and diagnosing infectious diseases.
This document discusses various staining techniques used to visualize bacteria under a microscope. It covers simple staining techniques like Gram staining and acid-fast staining, as well as methods to identify specific structures like volutin granules and bacterial spores. Gram staining uses dyes to differentiate between Gram-positive and Gram-negative bacteria based on their cell wall composition. Acid-fast staining targets bacteria with thick lipid cell walls like Mycobacterium tuberculosis. Specialized techniques employ unique dyes and fixation steps to highlight intracellular inclusions and endospores. Proper staining is crucial for bacterial identification and clinical diagnosis.
Normal flora, including bacteria, fungi and viruses, colonize various sites of the human body through mutualistic and commensal relationships. Microbiota commonly reside on the skin, in the mouth, respiratory tract, gastrointestinal tract, eyes, and genital region through tissue specificity involving bacterial adherence and biofilm formation preferential for certain tissues. While generally beneficial, microbiota can become pathogenic under conditions like immunosuppression or change in location. References included Medical Microbiology and Jawetz Melnick & Adelbergs Medical Microbiology textbooks.
1. Bacteria are unicellular prokaryotes that vary in size from 0.5-10 micrometers. They have distinct cell shapes including cocci, bacilli, spirilla, and vibrios.
2. The bacterial cell contains a cell membrane, cell wall, cytoplasm, and varying structures like flagella, pili, capsules, and endospores. The cell wall structure differs between gram positive and gram negative bacteria.
3. Gram staining allows bacteria to be classified as either gram positive or gram negative based on differences in their cell wall structures. Specialized structures like flagella, pili and capsules serve functions like motility, adhesion and virulence.
Direct microscopic examination of clinical specimens can provide a presumptive diagnosis of fungal infection by revealing the presence of fungal elements. Different stains and techniques are used to visualize fungi depending on the suspected infection. KOH wet mounts are useful for superficial mycoses while GMS, H&E and fluorescent antibody stains aid in diagnosis of deep mycoses from tissue biopsies and body fluids. Proper specimen collection and rapid microscopic evaluation can help initiate appropriate antifungal treatment.
Giving basic concepts regarding culture media and its classification on the basis of different properties like physical state, chemical composition and utility purposes.
This document discusses antibiotic sensitivity testing (AST), which determines how effective antibiotics are against bacteria in vitro. AST is important for selecting the best antibiotic treatment for patients, monitoring antibiotic resistance trends, and accumulating epidemiological data. The Kirby-Bauer disk diffusion method is described, which uses antibiotic-impregnated disks placed on agar plates inoculated with bacteria. The diameter of inhibition zones around the disks after incubation indicates antibiotic sensitivity. Interpretive criteria classify results as sensitive, intermediate, or resistant. AST provides guidance for clinicians in choosing effective antibiotic therapy.
Pure cultures are important in microbiology because they allow for the accurate study and identification of microorganisms. There are three main techniques involved in obtaining a pure culture: sterilization of materials to prevent contamination, aseptic transfer of microbes to growth media, and isolating single cells or their progeny. Some common isolation methods are streak plating, spread plating, and serial dilution plating. Once a pure culture is obtained, its purity can be demonstrated by the uniform appearance of colonies and identical growth characteristics of isolated colonies. Pure cultures must then be maintained through refrigeration, paraffin coating, cryopreservation, or lyophilization to preserve them for long-term storage and future use.
The normal flora are microorganisms that commonly live on and inside the healthy human body in different areas without causing issues. They can be divided into transient microbes that vary over time and resident microbes that persist. The types of microbes vary by body site, such as Staphylococcus and Streptococcus on the skin, Streptococcus and anaerobes in the mouth, and a diverse array of bacteria including E. coli in the large intestine. The composition of the normal flora is influenced by factors like age, hygiene, and diet.
The document discusses three methods for isolating pure cultures of microbes: streak plate technique, pour plate technique, and spread plate technique. The streak plate technique involves spreading microbial culture on media with a sterilized inoculating needle. The pour plate technique mixes culture with liquid agar before pouring into plates, trapping some microbes beneath the surface. The spread plate technique spreads diluted culture samples on the agar surface and is best for isolating pure colonies as it only produces surface colonies.
This document discusses antigens and their classification. It defines antigens as substances that can induce an immune response. Antigens are classified as either exogenous (external) or endogenous (internal) antigens. Exogenous antigens enter the body from the external environment, while endogenous antigens are further divided into xeno-genic, allogenic, and autologous antigens based on their origin. The document also discusses the properties of immunogens and antigens, as well as factors that contribute to immunogenicity.
The document outlines the classification and characteristics of medically important parasites. It discusses the classification of parasites into helminths (trematodes, cestodes, nematodes) and protozoa. For each type of parasite, it describes morphological features, life cycles, important stages, habitats, and modes of infection. The objectives are to differentiate parasite types based on these characteristics and list examples of medically significant parasites.
This document discusses various ways that bacteria can be classified, including phenotypic and genotypic classification. Phenotypically, bacteria are classified based on their morphology, anatomy, staining characteristics, culture growth, nutritional requirements, and environmental tolerances. Morphologically, bacteria are classified as cocci, bacilli, actinomycetes, spirochetes, mycoplasmas, or rickettsiae/chlamydiae depending on their shape and arrangement. Anatomical features used in classification include whether they have capsules, flagella, spores, and their gram stain reaction.
The document discusses various methods for diagnosing important bacterial diseases through laboratory examination. Effective diagnosis allows for timely treatment and control measures. Key methods discussed include microscopy, culture techniques, biochemical reactions, serological identification, and molecular diagnosis. Microscopy can identify bacterial morphology and staining properties. Culture techniques isolate bacteria on selective media and examine colony characteristics. Biochemical tests identify metabolic properties. Serology detects bacterial antigens and antibodies. Molecular methods like PCR and sequencing provide sensitive, specific identification and can detect non-culturable bacteria. Together, these diagnostic methods allow clinicians to initiate appropriate treatment and control of bacterial outbreaks.
This document provides an overview of bacterial anatomy, physiology, growth, nutrition, metabolism, toxins, and bacteriocins. It begins with an outline of the topics to be covered, including the structure and function of bacterial cell organelles, growth and nutrition, metabolism, toxins, and bacteriocins. The document then discusses the structure of the bacterial cell and its various components such as the cell wall, plasma membrane, mesosomes, nucleoid, plasmids, ribosomes, inclusion bodies, and endospores. It provides details on the cell wall structure of gram-positive and gram-negative bacteria. The document also covers bacterial metabolism, toxins, and bacteriocins.
Bacteria- Bacteria, the oldest and most diversified creatures on our planet, have a structure that is both basic and interesting.
Key points-
cell envelope- Investigate the bacterial cell's outermost layers, including the cell wall, cell membrane, and any other components that defend and preserve cell integrity.
cytoplasm and nucleotide- Discover the inner workings of bacterial cells, where genetic material is stored, metabolism occurs, and critical functions are organised.
Appandages and Flagella-Learn about the many appendages that bacteria can have, such as flagella, pili, and fimbriae, and how they help in motility and adherence.
Inclusions and Granules:Learn how bacteria adapt to their surroundings by storing energy and critical chemicals in the form of inclusions and granules.
Structural variation-Explore the variety of bacterial structure across various species and how these changes contribute to their adaptation and success.
Interactions and Ecological Importance: Investigate how bacteria's structure effects their interactions with other species and their significance in ecosystems.
This slide is presented by
Deepti Negi
Assistant professor
Pharmacology
Shri Guru Ram Rai University
Dehradun
Bacteria are single-celled microscopic prokaryotes that come in a variety of shapes and sizes. While some bacteria species are pathogenic, most are non-infectious and play important environmental roles. Bacteria have a cell membrane and cell wall but lack organized structures like a nucleus. Their genetic material is a tangled network of DNA localized in the cytoplasm. Bacteria use flagella or pili to move and a polysaccharide capsule for protection or attachment. The cell wall maintains shape and protects the cell from damage.
Bacteria are classified based on taxonomy, nomenclature, and observational techniques. Morphology, staining properties, motility, growth characteristics, biochemical activities, and genetics are used to classify and identify bacteria. Bacterial cells have a cell envelope consisting of a capsule, cell wall, and cell membrane. The cell envelope encloses cellular elements like ribosomes, nucleoid, and mesosomes. Some bacteria also have extracellular appendages like flagella and pili.
power point presentation on the topic cellular level of organization from unit first of subject human anatomy and physiology I for first year B.PHARM it is useful for the student to study easily and find out the material easily for their study it is also useful for techers
This document provides an overview of bacterial cell ultrastructure. It discusses the various internal and external structures of bacterial cells, including the cell wall, plasma membrane, cytoplasm, and inclusions. The cell wall provides structure and protection, and its composition differs between gram-positive and gram-negative bacteria. Membrane transport mechanisms like passive diffusion, facilitated diffusion, and active transport control movement of molecules into and out of the cell. The cytoplasm contains genetic material and carries out metabolic processes. Storage structures in the cytoplasm help bacteria survive in different environments.
The document summarizes the structure and functions of a normal human cell. It describes the main components of a cell including the nucleus that contains DNA, cytosol, cytoskeleton, and various organelles such as mitochondria, ribosomes, endoplasmic reticulum, Golgi apparatus, secretory vesicles, lysosomes, peroxisomes, and proteasomes. It also discusses cell membranes, transport through membranes, and transmission of messages across cell membranes through receptors and second messengers.
Prokaryotic cells lack membrane-bound organelles and have no nucleus. They contain genetic material in the form of a single circular chromosome located in the nucleoid region. Prokaryotic cells are much smaller than eukaryotic cells, ranging from 0.2 to 0.5 micrometers in diameter. The plasma membrane is a selectively permeable barrier that encloses prokaryotic cells and is composed of phospholipids and proteins arranged in a fluid mosaic structure. Ribosomes are the sites of protein synthesis in prokaryotes and are composed of RNA and protein. Inclusion bodies are insoluble protein aggregates that form in bacteria when they are forced to overproduce foreign proteins.
The plasma membrane is the outermost boundary of living cells. It is a selectively permeable membrane composed of lipids, proteins, and carbohydrates arranged in a fluid mosaic structure. The plasma membrane regulates the movement of materials in and out of cells and performs important functions like cell communication, recognition, and adhesion.
Bacterial cells have a typical prokaryotic structure, lacking organelles. They have an outer capsule or slime layer, a peptidoglycan cell wall, and an inner cell membrane. The cell wall provides structure and protection, and its composition differs between gram-positive and gram-negative bacteria. The cytoplasm contains genetic material, ribosomes, and other inclusions, and some bacteria possess flagella or pili for motility. Bacterial cells show diversity in their structures but share the basic prokaryotic organization.
This document provides information about ribosomes, mitochondria, and lysosomes. It describes them as follows:
Ribosomes are complex molecular machines found in all cells that function to synthesize proteins. They consist of RNA and proteins arranged into small and large subunits. Mitochondria are organelles that generate energy for cells through ATP production. They contain inner and outer membranes, intermembrane space, cristae, and matrix. Lysosomes contain enzymes that digest unwanted materials inside and outside of cells through autophagy and heterophagy.
This document provides information on the ultrastructure of bacteria. It discusses the main components found in bacterial cells such as the capsule, cell wall, flagella, fimbriae, cell membrane, ribosomes, nucleoid, and mesosome. It also compares the differences between gram-positive and gram-negative bacteria based on their cell wall structure and composition. Additionally, it covers bacterial classification based on morphology and describes various culture media used to grow bacteria in the laboratory.
The document summarizes the structure and functions of eukaryotic and prokaryotic cells. It describes the key components of cells including the cell membrane, nucleus, mitochondria, endoplasmic reticulum, Golgi apparatus, lysosomes, cytoskeleton and cytoplasm. It also discusses the differences between prokaryotic and eukaryotic cells and summarizes the mechanisms of transport across the cell membrane including passive diffusion and active transport.
This document summarizes the structure and functions of bacteria. It describes the key components of the bacterial cell, including the peptidoglycan cell wall, cytoplasmic membrane, cytoplasm, ribosomes, granules, nucleoid, and sometimes plasmids. It also discusses external structures like lipopolysaccharide in gram-negative bacteria, teichoic acid in gram-positive bacteria, capsules, flagella, and pili. Many of these structures are involved in bacterial pathogenesis and are targets for antibiotic drugs.
The plasma membrane surrounds cells and organelles, protecting the interior while regulating what passes in and out. It is a selectively permeable lipid bilayer containing proteins. The fluid mosaic model describes its structure as lipids and proteins moving freely within. Membranes are composed mainly of phospholipids, cholesterol, and glycolipids, with integral and peripheral proteins embedded. Transport across membranes includes passive diffusion, facilitated diffusion using carrier proteins, and active transport using ATP. Receptors on the surface receive signals from outside the cell.
1. Endocytosis and exocytosis are processes by which cells move materials into and out of the cell through the cell membrane. Endocytosis involves a part of the cell membrane enclosing extracellular fluids and molecules and breaking off into a vesicle inside the cell. Exocytosis involves secretory vesicles fusing with the plasma membrane and releasing their contents outside the cell.
2. There are several types of endocytosis, including phagocytosis which engulfs large particles, pinocytosis which absorbs fluids, and receptor-mediated endocytosis which selectively uptakes specific molecules bound to cell surface receptors.
3. Exocytosis releases contents from secretory vesicles to the extracellular space by vesicle fusion with the plasma membrane. It is important for
2- bacteriology.pptx a long descriptive information about bacteriaMuhammadAhmad135526
This document provides information on bacterial morphology, classification, and staining methods. It begins by classifying cells as either prokaryotic or eukaryotic. Bacteria are defined as unicellular prokaryotes that lack nuclei and organelles. Bacterial cells range in size from 0.1-5 micrometers. The document goes on to describe differences between gram-positive and gram-negative bacteria, including their cell wall structures. Key cellular components like peptidoglycan, teichoic acids, lipopolysaccharide, and external structures such as pili, fimbriae, and flagella are also discussed.
The document summarizes key components and structures of bacterial cells. It describes the cytoplasm as the site of cell functions and containing structures like ribosomes and plasmids. The cell envelope encases the cytoplasm and contains peptidoglycan and lipopolysaccharides. The nucleoid region contains bacterial DNA that is not enclosed in a membrane-bound nucleus. Other structures discussed include flagella, pili, inclusion bodies, and endospores.
Structure and function of plasma membrane 2ICHHA PURAK
The presentation consists of 72 slides,describes following heads
DEFINITION : STRUCTURE OF PLASMA MEMBRANE
COMPONENTS OF PLASMA MEMBRANE ( (BIOCHEMICAL PROPERTIES)
LIPID BILAYER
PROTEINS
CARBOHYDRATES
CHOLESTEROL
MODELS EXPLAINING STRUCTURE OF BIO MEMBRANE
FLUID MOSAIC MODEL
MOBILITY OF MEMBRANE
GLYCOCALYX : GLYCOPROTEINS AND GLYCOLIPIDS
TRANSPORT OF IONS AND MOLECULES ACROSS PLASMA MEMBRANE
FUNCTIONS OF PLASMA MEMBRANE
DIVERSITY OF CELL MEMBRANES
SITE OF ATPASE ION CARRIER CHANNELS AND PUMPS-RECEPTORS
The document discusses various methods for creating anaerobic conditions necessary for culturing anaerobic bacteria. It describes how oxygen is toxic to anaerobes and the importance of rapid specimen collection and transport to the laboratory with minimal oxygen exposure. Common methods for establishing anaerobic environments include incorporating chemical reducing agents into media, displacing oxygen with inert gases, and using anaerobic jars, chambers, or bags containing catalysts that convert oxygen to water. Proper selection and handling of clinical specimens, use of appropriate media, and correct incubation and processing are essential for successful anaerobic culture.
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This document discusses various epidemiological marker typing methods used to differentiate bacterial strains, including serotyping, bacteriocin typing, and colicin typing. Serotyping is based on antigenic differences expressed on bacterial cell surfaces and has good reproducibility but poor discriminatory power. Bacteriocin typing examines bacteriocin production and susceptibility patterns to distinguish strains. It has fair reproducibility and discriminatory power but some strains are non-typeable. Colicin typing specifically examines colicin production in E. coli strains using a spot culture method with indicator strains. These typing methods can help epidemiological studies and hospital infection control.
Echinococcus granulosus causes cystic hydatid disease in humans and livestock by forming hydatid cysts in organs. It has a two-host lifecycle between canines and herbivores. In humans, eggs ingested from contaminated dog feces hatch and form cysts usually in the liver or lungs. Cysts grow slowly and can cause symptoms from pressure or rupture. Diagnosis involves imaging, serology, and cyst puncture. Treatment is surgical removal of cysts and chemotherapy to prevent recurrence. Prevention focuses on deworming dogs and properly disposing of infected livestock organs.
This document discusses antibiotic resistance and its mechanisms. It defines antibiotic resistance as bacteria developing the ability to resist antibiotics and continue growing. Resistance can be intrinsic or acquired. Intrinsic resistance is natural to the bacteria through impermeability, efflux pumps, biofilms, or enzymatic inactivation. Acquired resistance develops from mutations during antibiotic exposure or gene transfer, allowing target modification, new targets, or enzymatic inactivation. The document examines specific resistance mechanisms and notes the need to slow resistance by completing antibiotic treatments.
Bacterial toxins and bacteriocins are important virulence factors produced by bacteria. There are two types of toxins - exotoxins and endotoxins. Exotoxins are proteins secreted outside the bacterial cell by both gram-positive and gram-negative bacteria, while endotoxins are lipopolysaccharides released after cell lysis of gram-negative bacteria. Bacteriocins are protein toxins produced by bacteria that have bactericidal activity against strains of the same or closely related bacterial species. They help protect the producing bacteria against pathogenic competitors. Bacteriocins are used in food preservation and bacteriocin typing aids in bacterial identification.
This document discusses quality assurance in clinical microbiology. It emphasizes that test results must be clinically relevant, reliable, timely, and correctly interpreted. It defines quality and discusses factors that influence it, including pre-analytical, analytical, and post-analytical stages. Total quality management aims to control all variables that could affect test quality. Standard operating procedures, good laboratory practices, and quality control procedures are important to ensure accurate results.
The document provides an overview of the complement system. It discusses the history and components of the three complement pathways: the classical pathway, lectin pathway, and alternative pathway. It also describes the roles of complement components in opsonization, chemotaxis, and formation of the membrane attack complex to lyse cells. The complement system is regulated to prevent damage to host cells. Deficiencies in complement proteins can increase susceptibility to certain infections.
This document discusses bacterial metabolism. It begins by defining metabolism as the sum of all chemical reactions occurring in a cell, and notes that bacterial metabolism is essential for bacterial existence, the environment, and produces medically and commercially important products. It then defines catabolic and anabolic reactions, and lists the main components of metabolism like enzymes, ATP, electron carriers, and precursor metabolites. The document goes on to describe various metabolic pathways like glycolysis, the pentose phosphate pathway, the Entner-Doudoroff pathway, cellular respiration, the Krebs cycle, electron transport chains, anaerobic respiration, and fermentation. It discusses the products of fermentation and specific pathways like lactic acid fermentation. Finally, it briefly
The document discusses the nutritional requirements and growth conditions of bacteria. It states that bacteria require water, a carbon and energy source, a nitrogen source, and inorganic salts for growth. The major macronutrients needed are carbon, oxygen, hydrogen, nitrogen, sulfur, and phosphorus. Some trace elements like iron, copper, and zinc are also required as cofactors for certain enzymes. Bacteria growth occurs through binary fission and is affected by temperature, oxygen levels, pH, osmotic pressure, and other environmental factors. Optimal growth occurs within a certain range for each factor.
B-cells develop and mature in the bone marrow from stem cells through distinct stages marked by specific cell surface markers and patterns of immunoglobulin gene expression. Mature B-cells leave the bone marrow and travel to peripheral lymphoid tissues where they are activated upon encountering antigen to produce plasma cells that secrete antibodies and memory B-cells. B-cell activation involves proliferation, somatic hypermutation, selection, and potential class switching in germinal centers to produce high affinity antibodies and long-lasting immunological memory. This allows for a rapid secondary immune response upon re-exposure to the same antigen.
The document discusses autoimmunity, which occurs when the immune system mistakenly attacks and damages normal body tissues. It begins by explaining how self-tolerance normally prevents this but can fail. Autoimmune diseases are then caused by a variety of mechanisms, including molecular mimicry between foreign and self-antigens. Both organ-specific diseases that target single organs, as well as systemic diseases with widespread effects, are described. Specific examples like Graves' disease, systemic lupus erythematosus, and rheumatoid arthritis are outlined.
This document provides information on antibody structure and function. It discusses that antibodies are glycoproteins produced in response to antigens that can recognize and bind to antigens. The basic antibody structure consists of two light chains and two heavy chains connected by disulfide bonds. The heavy chains determine the antibody class (IgG, IgA, etc.), which have different structures and functions. The document also covers antibody domains, classes, properties, antigen recognition, and the differences between polyclonal and monoclonal antibodies.
These lecture slides, by Dr Sidra Arshad, offer a quick overview of the physiological basis of a normal electrocardiogram.
Learning objectives:
1. Define an electrocardiogram (ECG) and electrocardiography
2. Describe how dipoles generated by the heart produce the waveforms of the ECG
3. Describe the components of a normal electrocardiogram of a typical bipolar lead (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
6. Describe the flow of current around the heart during the cardiac cycle
7. Discuss the placement and polarity of the leads of electrocardiograph
8. Describe the normal electrocardiograms recorded from the limb leads and explain the physiological basis of the different records that are obtained
9. Define mean electrical vector (axis) of the heart and give the normal range
10. Define the mean QRS vector
11. Describe the axes of leads (hexagonal reference system)
12. Comprehend the vectorial analysis of the normal ECG
13. Determine the mean electrical axis of the ventricular QRS and appreciate the mean axis deviation
14. Explain the concepts of current of injury, J point, and their significance
Study Resources:
1. Chapter 11, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 9, Human Physiology - From Cells to Systems, Lauralee Sherwood, 9th edition
3. Chapter 29, Ganong’s Review of Medical Physiology, 26th edition
4. Electrocardiogram, StatPearls - https://www.ncbi.nlm.nih.gov/books/NBK549803/
5. ECG in Medical Practice by ABM Abdullah, 4th edition
6. Chapter 3, Cardiology Explained, https://www.ncbi.nlm.nih.gov/books/NBK2214/
7. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
share - Lions, tigers, AI and health misinformation, oh my!.pptxTina Purnat
• Pitfalls and pivots needed to use AI effectively in public health
• Evidence-based strategies to address health misinformation effectively
• Building trust with communities online and offline
• Equipping health professionals to address questions, concerns and health misinformation
• Assessing risk and mitigating harm from adverse health narratives in communities, health workforce and health system
Cell Therapy Expansion and Challenges in Autoimmune DiseaseHealth Advances
There is increasing confidence that cell therapies will soon play a role in the treatment of autoimmune disorders, but the extent of this impact remains to be seen. Early readouts on autologous CAR-Ts in lupus are encouraging, but manufacturing and cost limitations are likely to restrict access to highly refractory patients. Allogeneic CAR-Ts have the potential to broaden access to earlier lines of treatment due to their inherent cost benefits, however they will need to demonstrate comparable or improved efficacy to established modalities.
In addition to infrastructure and capacity constraints, CAR-Ts face a very different risk-benefit dynamic in autoimmune compared to oncology, highlighting the need for tolerable therapies with low adverse event risk. CAR-NK and Treg-based therapies are also being developed in certain autoimmune disorders and may demonstrate favorable safety profiles. Several novel non-cell therapies such as bispecific antibodies, nanobodies, and RNAi drugs, may also offer future alternative competitive solutions with variable value propositions.
Widespread adoption of cell therapies will not only require strong efficacy and safety data, but also adapted pricing and access strategies. At oncology-based price points, CAR-Ts are unlikely to achieve broad market access in autoimmune disorders, with eligible patient populations that are potentially orders of magnitude greater than the number of currently addressable cancer patients. Developers have made strides towards reducing cell therapy COGS while improving manufacturing efficiency, but payors will inevitably restrict access until more sustainable pricing is achieved.
Despite these headwinds, industry leaders and investors remain confident that cell therapies are poised to address significant unmet need in patients suffering from autoimmune disorders. However, the extent of this impact on the treatment landscape remains to be seen, as the industry rapidly approaches an inflection point.
These lecture slides, by Dr Sidra Arshad, offer a simplified look into the mechanisms involved in the regulation of respiration:
Learning objectives:
1. Describe the organisation of respiratory center
2. Describe the nervous control of inspiration and respiratory rhythm
3. Describe the functions of the dorsal and respiratory groups of neurons
4. Describe the influences of the Pneumotaxic and Apneustic centers
5. Explain the role of Hering-Breur inflation reflex in regulation of inspiration
6. Explain the role of central chemoreceptors in regulation of respiration
7. Explain the role of peripheral chemoreceptors in regulation of respiration
8. Explain the regulation of respiration during exercise
9. Integrate the respiratory regulatory mechanisms
10. Describe the Cheyne-Stokes breathing
Study Resources:
1. Chapter 42, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 36, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 13, Human Physiology by Lauralee Sherwood, 9th edition
One health condition that is becoming more common day by day is diabetes.
According to research conducted by the National Family Health Survey of India, diabetic cases show a projection which might increase to 10.4% by 2030.
Travel vaccination in Manchester offers comprehensive immunization services for individuals planning international trips. Expert healthcare providers administer vaccines tailored to your destination, ensuring you stay protected against various diseases. Conveniently located clinics and flexible appointment options make it easy to get the necessary shots before your journey. Stay healthy and travel with confidence by getting vaccinated in Manchester. Visit us: www.nxhealthcare.co.uk
Osteoporosis - Definition , Evaluation and Management .pdfJim Jacob Roy
Osteoporosis is an increasing cause of morbidity among the elderly.
In this document , a brief outline of osteoporosis is given , including the risk factors of osteoporosis fractures , the indications for testing bone mineral density and the management of osteoporosis
- Video recording of this lecture in English language: https://youtu.be/kqbnxVAZs-0
- Video recording of this lecture in Arabic language: https://youtu.be/SINlygW1Mpc
- Link to download the book free: https://nephrotube.blogspot.com/p/nephrotube-nephrology-books.html
- Link to NephroTube website: www.NephroTube.com
- Link to NephroTube social media accounts: https://nephrotube.blogspot.com/p/join-nephrotube-on-social-media.html
Rasamanikya is a excellent preparation in the field of Rasashastra, it is used in various Kushtha Roga, Shwasa, Vicharchika, Bhagandara, Vatarakta, and Phiranga Roga. In this article Preparation& Comparative analytical profile for both Formulationon i.e Rasamanikya prepared by Kushmanda swarasa & Churnodhaka Shodita Haratala. The study aims to provide insights into the comparative efficacy and analytical aspects of these formulations for enhanced therapeutic outcomes.
Hiranandani Hospital in Powai, Mumbai, is a premier healthcare institution that has been serving the community with exceptional medical care since its establishment. As a part of the renowned Hiranandani Group, the hospital is committed to delivering world-class healthcare services across a wide range of specialties, including kidney transplantation. With its state-of-the-art facilities, advanced medical technology, and a team of highly skilled healthcare professionals, Hiranandani Hospital has earned a reputation as a trusted name in the healthcare industry. The hospital's patient-centric approach, coupled with its focus on innovation and excellence, ensures that patients receive the highest standard of care in a compassionate and supportive environment.
Vestibulocochlear Nerve by Dr. Rabia Inam Gandapore.pptx
Bacterial anatomy
1. Santosh Yadav
BACTERIAL ANATOMY, PHYSIOLOGY,
GROWTH AND NUTRITION
AND
BACTERIAL METABOLISM,
TOXINS AND BACTERIOCINS
Santosh Yadav
M.Sc. Clinical Microbiology
Dept. of Microbiology
Institute of Medicine
Tribhuvan Univarsity Teaching Hospital, Nepal
2. Santosh Yadav
Outline
2
Structure and function of different bacterial cell
organelles.
Growth and nutrition of bacteria.
Bacterial metabolism and different pathways.
Bacterial toxins and their clasiification.
Bacteriocins, their classification ,mode of action
and typing.
4. Santosh Yadav
Bacterial cell structure Cell wall
Internal to cell wall
(Plasmamembrane,Mesosome,Nucleoid,Plasmid,Ribosome,Inclusi
on body,Endospore)
External to cell wall(capsule,Flagella,Pili)
3 – 5 um ₓ 0.2 – 1.5 um
5. Santosh Yadav
CELL WALL
Encloses the
protoplast and lies
immediately external
to the cytoplasmic
membrane.
Relatively rigid with
some elasticity, and
openly porous.
Freely permeable to
solute molecules
smaller than 10 kDa
in mass and 1 nm in
diameter.
Thickness depends
on type of bacteria.
Gram positive Gram
negative
6. Santosh Yadav
Comparision of cellwall
6
Gram positive Gram negative
Thickness Thicker Thinner
Peptidoglycan 40-65 sheets 1-2 sheets
Varieties of amino
acids
Few Several
Lipids Absent or scant Present
Teichoic acid present Absent
Lipopolysaccharide
s
Absent Present
7. Santosh Yadav
Cell wall of Gram positive bacteria
Composed of
peptidoglycan and
techoic acid.
Peptidoglycan comprises
up to about 50% of the cell
wall material.
Peptidoglycan layer is 15-
50 nm thick.
8. Santosh Yadav
The peptidoglycan layer
Complex polymer consisting of three parts:
a)Backbone of cellwall, glycan (polymer of alternating
N-acetylglucosamine(NAG) and N-acetylmuramic acid (NAM);
b) tetrapeptide side chains attached to(NAM); and
c) peptide interbridges.
10. Santosh Yadav
Teichoic acid
Major surface antigen of
Gram positive bacteria.
Chains of either ribitol-
phosphate or glycerol
phosphate,to which various
sugars and D-alanine are
usually attached.
Two types:-
lipotechoic acid (attached to
cytoplasmic membrane) and
wall techoic acid ( those
attached to NAM portion of
peptidoglycan of cell wall)
12. Santosh Yadav
Cell wall of Gram negative bacteria
• Composed of peptidoglycan and outermembrane.
• Peptidoglycan comprises 5-10% of the wall material
(thickness 2-6 nm).
Outer membrane contain three components:
lipoprotein ,phospholipid and lipopolysaccharide.
13. Santosh Yadav
Peptidoglycan Cross-Links. (a) E. coli peptidoglycan
with direct cross-linking, typical of many gram-negative bacteria.
(b) Staphylococcus aureus peptidoglycan. S. aureus is a gram-
positive
bacterium. NAM is N-acetylmuramic acid. NAG is N-acetylglucosamine.
Gly is glycine.
13
Peptidoglycan of Gram negative
bacteria
14. Santosh Yadav
Lipoprotein
• lipoprotein cross-link the outer membrane and
peptidoglycan layers.
• Is peptide, linked to DAP residues of the
peptidoglycan .
• Function is to stabilize the outer membrane and
anchor it to the peptidoglycan layer .
Outermembrane
15. Santosh Yadav
Phospholipid of outer
membrane
15
Is distinct from all other biological membranes
Its outer leaflet contains a
lipopolysaccharides.
Has special channels, consisting of protein
molecules called porins.
16. Santosh Yadav
Lipopolysaccharide (LPS)
outermost part of
cellwall of Gram
negative bacteria.
Consists of
lipid A,
core
polysaccharide and
a terminal series of
repeat units ( O
antigen).
17. Santosh Yadav
Bacteria with atypical cell wall
17
Mycobacteria and
Nocardia.
Contains high
concnentration (
around 60%) of
hydrophobic waxy lipid ,
mycolic acid.
Mycolic acid prevent the
uptake of dye .
Mycolic acids are present
outside the thin
peptidoglycan layer linked
by polysaccharides.
18. Santosh Yadav
Bacteria without cell wall
Mycoplasma .
Plasmamembrane of
Mycoplasma contain
sterol that are tough
to protect from lysis.
20. Santosh Yadav
Functions of cell wall
Provides shape to the bacterium.
Give rigidity to the organism.
Protects from environment.
Contains receptor sites for phages.
Provides attachment to complement.
Contains components toxic to host.
Site of action of colicin.
21. Santosh Yadav
Cytoplasmic membrane( plasma
membrane)
21
Lies beneath the cell wall and separating it from the cell
cytoplasm.
5-10 nm thick, elastic and semipermeable layer and
comprises about 30% of the dry weight of bacterial cell.
Composed of mainly phospholipid (20-30%) and proteins
(70-80%).
Phospholipids form bilayered structure in which proteins
are embedded.
Phospholipid has two parts:
Hydrophillic head
Hydrophobic tail
Two types of proteins are found:
peripheral protein
integral protein
Many enzymes are also present.
23. Santosh Yadav
Functions of plasma
membrane
Regulates the transport of nutrients and
waste products into and out of the cell
Synthesis of cell wall components
Assists in DNA replication
Secretes proteins
Carries on electron transport system
Captures energy in the form of ATP, etc.
25. Santosh Yadav
Simple or passive diffusion
Solute molecules cross the membrane as a result of a
difference in concentration of molecules across the
membrane.
Speed and direction of diffusion depends on the relative
concentration of molecules on each side of the
membrane.
Ref: Microbiology by M.J.
26. Santosh Yadav
Facilitated diffusion
Similar to that of simple diffusion.
But requires carrier protein called permease located in
the cytoplasmic membrane.
Entry of glycerol.
Ref: Microbiology by M.J. Pelczar
27. Santosh Yadav
Group translocation
• Accumulates the solute inside the cell against concentration gradient
• Solute molecule altered chemically during transport.
• PEP-dependent sugar-phosphotransferase system.
• A heat stable carrier protein (HPr) is first activated by transfer of
phosphate group from PEP inside the cell .
• At the same time sugar combines with enzyme II at the outer
membrane surface and is transported to inner membrane surface .
Here it combines with phosphate group carried by activated HPr.
Ref: Microbiology by M.J.
Pelczar
28. Santosh Yadav
Active Transport
Almost all solutes , including sugars, amino acids, peptides,
nucleosides, and ions are taken up by cells through active transport.
• Entry of solutes occurs in three steps:-
1)Binding of solute to carrier protein.
2)Translocation of the solute- carrier complex, and
3)Coupling of translocation to an energy yielding reaction to lower the
affinity of the carrier protein for the solute at the inner membrane
surface so that the carrier protein will release solute to the cell
interior.
Ref: Microbiology by M.J.
29. Santosh Yadav
Two primary mechanisms of active transports, each utilizing a
different form of energy.
A. Transport system that use proton motive force
Uniporters : (eg. Potassium enters the cell via uniporter)
Antiporters: (eg. Sodium is transported out of the cell as a
proton passes in )
Symporters :(eg. A lactose molecule enters a cell with one
proton)
Contd…
30. Santosh Yadav
30
B.Transport system that
use ATP:-
ABC transport
system: (ABC stands for
ATP Binding Cassette)
The ABC transport
system utilizes a binding
protein that resides
immediately outside of
the cytoplasmic
membrane to deliver a
given molecule to a
specific transport
complex within the
membrane.
Contd…
31. Santosh Yadav
Mesosome
31
Convoluted or multilaminated
membranous bodies.
Develop by complex
invagination of the
cytoplasmic membrane into the
cytoplasm.
Function
(1)Compartment of DNA at cell
division and at sporulation.
(2)Are principal sites of respiratory
enzymes.(analogous to the
mitochondria of the eukaryotic
cell)
32. Santosh Yadav
Nucleoid (nuclear material)
32
Nucleoid contains a
single dsDNA , which
carry genetic
information for cell.
Circular thread about 1
mm long, being
condensed and looped
into a supercoiled state,
located centrally.
Nuclear division
preceeding cell division,
two DNA may be
present.
33. Santosh Yadav
Contd…
33
Chromosomes have 2,000 to 4,000 genes.
Many genes that encodes virulence factors (
adhesins, invasins, exotoxins,etc) are clustered
adjacent to each other on chromosome , called
pathogenicity islands.
These islands range in size from 10 to 200 kB.
Can be horizontally transferred between
bacteria, resulting in enhanced virulence in the
recipient.
made visible under the light microscope by
Feulgen staining ( specific for DNA).
34. Santosh Yadav
Plasmid
Many bacteria possess
plasmids in addition to
chromosome.
Are circular dsDNA
molecules .
size from 1.5 kilobase (kb)
pairs to 120 kb pairs (less
than one tenth the size of
the bacterial chromosome)
Can exist and replicate
independently of the
chromosome or may be
integrated with it.
Not required for host
growth
and reproduction.
35. Santosh Yadav
Classification of plasmid
35
Relaxed plasmid : Plasmid occur free in the cytoplasm
and replicate independent of bacterial genome replication
Stringent plasmid: plasmid that integrate and replicate
along with bacterial chromosome.
37. Santosh Yadav
Ribosome
Is spherical and granular structure with diameter of 100-
200 A.
Present in cytoplasm and may loosely attached to the
plasma membrane.
Made up of both protein and ribonucleic acid (RNA).
70s type.
Each 70s has two subunit :- larger 50s and smaller 30s.
30S
50
S
50
S
30S
39. Santosh Yadav
Functions
39
Site of protein synthesis;
Matrix ribosomes synthesize proteins to remain
within the cell and Plasma membrane ribosomes
make proteins for transport to the outside.
40. Santosh Yadav
Inclusion body
Are reserve deposits of
bacterial cell.
Cells accumulate nutrient
when they are plenty and
use when deficient.
Metachromatic
granules:-
Reserve of polyphosphate
used in synthesis of ATP.
Characteristics of
Corynebacterium
diphtherie.
41. Santosh Yadav
41
Polysaccharide granules:-
Mainly consists of glycogen and starch.
Lipid inclusions:-
Poly – B-hydroxybutyric acid.
Found in several species of Mycobacteria, Bacillus, Azotobacter, etc
Sulphur granules:- Present in sulphur bacteria .eg. Thiobacillus.
Carboxysomes :- contain enzyme ribulose-1,5-diphosphate
carboxylase ,helps in CO2 fixation in photosynthetic bacteria (
Cyanobacteria and Thiobacillus, etc ).
Gas vacuoles:-
Hollow cavities found in aquatic procaryotes.
Consists of gases covered with proteins.
Magnetosomes :-
Inclusion of iron oxide. (Fe3O4)
Decompose hydrogen peroxide.
Found in Magnetospirillum , Magnetotactium, etc.
Contd…
42. Santosh Yadav
Endospore
42
Highly resistant phase of
bacteria, formed in
unfavorable condition.
Formed internal to
bacterial cell.
Can survive in extreme
heat, lack of water, many
chemicals, radiation , etc..
STRUCTURE:-
1)Core ,
2)Core wall,
3) Cortex,
4)Coat , and
5)Exosporium .
43. Santosh Yadav
Contd…
43
Resistance property of endospore is due to
- impermeability of their cortex and outer coat,
- high content of calcium and dipicolinic acid,
- low content of water (5-20%),
- very low metabolic and enzyme activity,
- DNA-binding proteins saturate spore DNA and protect it
from heat.
45. Santosh Yadav
Contd…
45
Sporulation, occurs when growth ceases due to lack of
nutrients.
Steps:-
• An axial filament of nuclear material forms.
• An inward folding of the cell membrane to enclose part
of the DNA and produce the forespore septum.
• The membrane continues to grow and engulfs the
immature spore in a second membrane.
• Cortex is laid in the space between the two membranes,
and both calcium and dipicolinic acid are accumulated.
• Protein coats then are formed around the cortex.
• Maturation of the spore occurs.
• Lytic enzymes destroy the sporangium releasing the
spore.
47. Santosh Yadav
Contd…
47
It has been estimated that 7500- year old endospore of Thermoactinomyces vulgaris
from the freezing muds of Elk lake in Minnesota have germinated when warmed and
placed in a nutrient medium.
The transformation of dormant spores into active vegetative cells is complex process.
It occurs in three stages:
(1) Activation,
(2) Germination, and
(3) Outgrowth.
1)An endospore will not germinate successfully, even in a nutrient-rich medium, unless it
has been activated.
Activation is a reversible process that prepares spores for germination and usually
results from heat treatments.
2)It is followed by germination, the breaking of the spore’s dormant state.
It is characterized by spore swelling, rupture or absorption of the spore coat,
loss of refractility,
Release of spore components, and increase in metabolic activity.
Many normal metabolites or nutrients (e.g., amino acids and sugars) can
trigger germination after activation.
3)Grmination is followed by the outgrowth.
The spore protoplast makes new components and develops again into an
48. Santosh Yadav
Central (eg. Clostridium bifermentans)
Subterminal ( eg. Cl. Perfringens)
Oval and terminal ( eg. Cl. tertium)
Spherical and terminal (eg.Cl. tetani)
49. Santosh Yadav
Demonstration of spore
Spore stain ( Shaeffer –Fulton and Dorner method)
Modified Ziehl Neelsen stain ( resist to
decolorisation by 0.25 % H2SO4)
Evidence of presence of spore can can also be
obtained by Gram staining where spore remains
unstained.
49
51. Santosh Yadav
Capsule and slime layers
Hydrophobic gelatinous
material sectreted outside
and lies immediately in
contact with the cell wall.
Consists largely of water
and small content of
solids (2%).
In most species, the solid
material is a
complex
polysaccharide, though
in some species
polypeptide or protein.
52. Santosh Yadav
Contd…
When the material is tightly associated with cell wall it is
called capsule.
Capsules too thin to seen under the light microscope is
called microcapsule.
Slime is an amorphous, colloidal material secreted
extracellularly by some non-capsulated bacteria and also
by many capsulated bacteria outside their capsules.
Glycocalyx is the term used for any carbohydrate
molecule present on surface of cell.
53. Santosh Yadav
Functions of capsule
Protecting the cell wall against attack by various
kinds of antibacterial agents, e.g. bacteriophages,
colicins, complement, lysozyme and other lytic
enzymes. Thus the capsule is an important
virulence determinant.
Is usually antigenic and the capsular antigens
play a very important part in determining the
antigenic specificity of bacteria.
Helps to adhere bacteria to surface.
Prevents from Phagocytosis.
54. Santosh Yadav
Method of demonstration
54
1) Negative staining.
2) Special capsule
staining using CuSO4
as mordant.
3) Quellung reaction
56. Santosh Yadav
Flagella
Organ of locomotion.
Long , thin filaments,
regular.
15-20 nm thick and several
times the length of the
bacteria cell.
Originating in the bacterial
protoplasm and extruded
through the cell wall.
Made up of several
thousand molecules of a
protein subunit called
flagellin.
57. Santosh Yadav
Structure
A flagellum has three basic parts:-
Outer filament, contains the globular protein flagellin.
Filament is attached to a slightly wider hook, consisting
of different protein, and
The basal body, which anchors the flagellum to the cell
wall and plasma membrane.
58. Santosh Yadav
Flagellar arrangements
•Bacteria without flagella are called atrichous.
The arrangement of flagella may be
Polar flagella :- flagella at one or both end.
Monotrichous:- single flagellum at one end (eg. Vibrio cholera)
Amphitrichous:- single flagellum at both ends (eg. Alkaligenes faecalis)
Lophotrichous:- tuft of flagella at one or both end (eg. Helicobacter
pylori)
Peritrichous flagella:- flagella arranged all round the body (eg.
Escherichia coli , Proteus , etc)
59. Santosh Yadav
Flagella and bacterial motility
The movement of flagella results
from rotation of basal body.
As the flagella rotates ,they form
a bundle that pushes against the
surrounding liquid and propels
the bacterium and the flagellar
rotation depends on the cells
countinuous generation of
energy.
Bacterial cells can alter the
speed and direction of rotation of
flagella and thus are capable of
various patterns of motility.
When a bacterium moves in one
direction for a length of time
,called run or swim.
Runs are interrupted by random
changes in direction called
tumble,caused by reversal of
flagellar rotation.
60. Santosh Yadav
contd…
The energy required for rotation of the flagellum comes from the
proton motive force.
Proton movement across the cytoplasmic membrane through the
Mot complex drives rotation of the flagellum.
In this model called the proton turbine model, protons flowing
through channels in the Mot proteins exert electrostatic forces on
helically arranged charges on the rotor proteins.
Attractions between positive and negative charges would then
cause the basal body to rotate as protons flow though the Mot
proteins.
61. Santosh Yadav
Demonstration of motility
Hanging drop technique,
Flagella stain,
Growing in semisolid agar
media,
Craigie’s tube,
U –tube.
Craigies tube U-tube
Flagella stain
62. Santosh Yadav
Axial filament or endoflagella
Present in spirochetes .
Are bundle of fibrils, arise at the ends of the cell and
spiral around the cell.
have structure similar to that of flagella.
The rotation of the filaments produces movement of the
outer sheath that propells the spirochetes in spiral
motion.
63. Santosh Yadav
Pili or Fimbriae
Organ of adhesion.
Short , hairlike appendages thinner and smaller than
flagella, originated from cellwall.
About 3 -10 um in length and 0.03-o.2nm in diameter.
Composed of helically arranged protein subunits , pilin.
Some fimbriae cause hemagglutination with RBC of
guinea pig, fowl, horses, etc and can be inhibited by 0.1-
0.5% D-mannose (MS).
64. Santosh Yadav
Types of fimbriae
64
6 types of fimbriae.
Type1 : relatively thick and involve in haemagglutination
(MS), (E. coli, Salmonella spp).
Type2 : resembles MS type1 but non-haemagluttinating( S.
gallinarum, S. pullorum).
Type3 : thin and MR and cause indirect haemagglutination
(RBC treated with tannic acid),( Proteus spp).
Type4 : thinner than MR type3 fimbriae and have MR
haemagglutinating activity for fresh RBC.
Type5 : are very long ( some Klebsiella spp)
Type6 : are monopolar and found only in Pseudomonas
spp.
65. Santosh Yadav
Function of pilli
65
Commom pili (fimbriae): Playing a role in the
adherence of symbiotic and pathogenic bacteria to host
cells.
(Minor proteins termed adhesins are located at the tips
of pili and are responsible for the attachment properties).
66. Santosh Yadav
Sex pili: long and flexible structure,being
responsible for the attachment of donor and
recipient cells in bacterial conjugation.
Pili also help in formation of pellicle on
surface of stagnant liquid medium.
Contd…