Lect. 5 (factors affecting microbial growth)
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General Microbiology for 2nd year biology departments
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Pure culture technic
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.
Pure culture techniques
The learner will understand various methods like streak plate technique, pour plate technique, spread plate technique and micromanupulator technique
Factors affecting growth of bacteria
The physical factors affects the growth of microorganism.
1) Temperature
Temperature is the most important factor that influences the rate of enzyme catalysed reactions and rate of growth.
For every organisms there is an optimum temperature for growth and minimum temperature for inhibiting the growth.
Most extreme the microbes need liquid water to grow.(330C).
some algae and fungi grow at 55-60 degreeC.
Prokaryotes are grow at 100 degreeC.
Based on temperature the microorganisms are classified into two 4.
Bacterial growth curve
Bacterial growth follows four phases: lag, log (exponential), stationary, and decline. During lag phase, bacteria adapt to their environment and prepare for growth. The log phase is characterized by rapid, exponential cell division. As nutrients become depleted, growth slows and enters stationary phase where the cell population levels off. In decline phase, bacteria run out of nutrients and die off, though a small number of survivors may persist. Bacterial growth is influenced by numerous environmental factors like nutrient levels, temperature, pH, oxygen, and water availability. The optimal conditions allow bacteria to enter log phase and multiply at their highest rate.
Endospores
The document discusses bacterial endospores. Endospores are resistant structures formed by some bacteria, like Clostridium and Bacillus, to survive adverse conditions. They provide resistance to heat, drying, radiation, and chemicals. Specific endospore proteins and calcium-dipicolinic acid complexes help dehydrate and stabilize the DNA in the core. Not all bacteria can form endospores. The shape and location of endospores can help identify bacteria. Some endospore-forming bacteria can cause diseases like botulism and tetanus.
Pure culture preservation and maintenanace
Pure cultures are maintained for a long time for further evaluation using different techniques and procedures
Endospore
Bacterial spores are dormant, resistant structures formed by certain bacteria under stressful conditions. They have a thick coat that allows them to survive extreme heat, lack of water, toxins, and radiation. There are two types of spore formation: endospores form inside the parent cell while exospores bud off externally. Endospores contain dipicolinic acid which makes them highly resistant. Germination occurs in three stages - activation by damage to the coat, initiation by effectors in a rich environment, and outgrowth involving degradation of spore layers and emergence of a new vegetative cell.
Microbial growth
Microbial growth involves an increase in cell size or population numbers through cell division and reproduction. There are two levels of growth - increasing cell size through synthesis of new components, and increasing population size through cell division. Microbiologists study population growth curves, which typically have four phases: lag phase as cells adapt, exponential or log phase of rapid growth, stationary phase as resources are depleted, and death phase. Growth is measured by counting cell numbers directly under a microscope or using counting chambers, or indirectly by culturing cells on agar plates and counting colonies. Environmental factors like nutrients, oxygen, pH, and temperature affect microbial growth rates.
Recommended
Pure culture technic
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.
Pure culture techniques
The learner will understand various methods like streak plate technique, pour plate technique, spread plate technique and micromanupulator technique
Factors affecting growth of bacteria
The physical factors affects the growth of microorganism.
1) Temperature
Temperature is the most important factor that influences the rate of enzyme catalysed reactions and rate of growth.
For every organisms there is an optimum temperature for growth and minimum temperature for inhibiting the growth.
Most extreme the microbes need liquid water to grow.(330C).
some algae and fungi grow at 55-60 degreeC.
Prokaryotes are grow at 100 degreeC.
Based on temperature the microorganisms are classified into two 4.
Bacterial growth curve
Bacterial growth follows four phases: lag, log (exponential), stationary, and decline. During lag phase, bacteria adapt to their environment and prepare for growth. The log phase is characterized by rapid, exponential cell division. As nutrients become depleted, growth slows and enters stationary phase where the cell population levels off. In decline phase, bacteria run out of nutrients and die off, though a small number of survivors may persist. Bacterial growth is influenced by numerous environmental factors like nutrient levels, temperature, pH, oxygen, and water availability. The optimal conditions allow bacteria to enter log phase and multiply at their highest rate.
Endospores
The document discusses bacterial endospores. Endospores are resistant structures formed by some bacteria, like Clostridium and Bacillus, to survive adverse conditions. They provide resistance to heat, drying, radiation, and chemicals. Specific endospore proteins and calcium-dipicolinic acid complexes help dehydrate and stabilize the DNA in the core. Not all bacteria can form endospores. The shape and location of endospores can help identify bacteria. Some endospore-forming bacteria can cause diseases like botulism and tetanus.
Pure culture preservation and maintenanace
Pure cultures are maintained for a long time for further evaluation using different techniques and procedures
Endospore
Bacterial spores are dormant, resistant structures formed by certain bacteria under stressful conditions. They have a thick coat that allows them to survive extreme heat, lack of water, toxins, and radiation. There are two types of spore formation: endospores form inside the parent cell while exospores bud off externally. Endospores contain dipicolinic acid which makes them highly resistant. Germination occurs in three stages - activation by damage to the coat, initiation by effectors in a rich environment, and outgrowth involving degradation of spore layers and emergence of a new vegetative cell.
Microbial growth
Microbial growth involves an increase in cell size or population numbers through cell division and reproduction. There are two levels of growth - increasing cell size through synthesis of new components, and increasing population size through cell division. Microbiologists study population growth curves, which typically have four phases: lag phase as cells adapt, exponential or log phase of rapid growth, stationary phase as resources are depleted, and death phase. Growth is measured by counting cell numbers directly under a microscope or using counting chambers, or indirectly by culturing cells on agar plates and counting colonies. Environmental factors like nutrients, oxygen, pH, and temperature affect microbial growth rates.
Nutritional requirement by microorganisms
Nutrients are required for microbial growth and act as building blocks and energy sources. The main nutrient requirements for microorganisms include carbon, nitrogen, phosphorus, sulfur, hydrogen, oxygen, potassium, calcium, magnesium, iron and trace elements. Microorganisms can be classified based on their carbon, energy and electron sources as photolithotrophs, photoorganoheterotrophs, chemolithoautotrophs, chemolithoheterotrophs or chemoorganoheterotrophs. Culture media are used to grow microorganisms and include defined, complex, liquid, solid, supportive, enriched, selective and differential media depending on their composition and purpose.
sporulation
This document summarizes the process of sporulation in microorganisms. It describes that spores form as a protective structure during unfavorable conditions and can survive without nutrients. There are two main types of spores - endospores, which form inside the cell, and exospores, which form on the surface. Spores have protective coats, cortex, germ cell wall, and a central core containing DNA. Sporulation is the process where a single cell forms an endospore or exospore, which can later germinate into a new cell under favorable conditions. Key factors like sigma factors regulate genes involved in sporulation and returning to the vegetative state.
Nutritional requirements of microorganisms
The document discusses the basic nutritional requirements of microorganisms. It notes that microbes require nutrients like carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur for biosynthesis and energy. These nutrients are obtained from both inorganic and organic sources. Microorganisms are also classified based on how they obtain carbon and energy, into four main types: photolithotrophs, photoheterotrophs, chemolithotrophs and chemoheterotrophs. The document provides details on the various microbial growth factors and nutritional types.
pure culture isolation
The document discusses various methods for obtaining pure bacterial cultures, which is necessary for studying individual bacterial species. The key methods are streak plating, pour plating, and spread plating. Streak plating involves streaking bacterial samples on an agar plate to isolate single colonies. Pour plating involves adding a liquid sample to molten agar before pouring into a plate. Spread plating involves spreading a diluted sample evenly on an agar surface. Serial dilution is also used to quantify the original number of bacteria in a sample through successive dilutions.
Pure culture technique
This document discusses techniques for obtaining a pure culture from a mixed culture sample. It explains that a pure culture contains only one type of microorganism, while a mixed culture contains multiple types. The most common laboratory methods for isolating microbes are the streak plate method and pour plate method. Both rely on diluting bacterial cells to a point where single colonies can grow from individual cells. The streak plate method involves transferring a sample to an agar plate using a sterilized loop and streaking the inoculum in sections to separate individual colonies.
Isolation and characterization of microbes
This document discusses the isolation and characterization of microbes. It defines key terms like microbes, pure culture, mixed culture, species, and strain. It describes common methods used to isolate pure cultures from mixed populations, including streak plate technique, micromanipulator method, enrichment culture method, and serial dilution method. The document also discusses maintaining and preserving pure cultures through refrigeration, cryopreservation, and lyophilization. It explains how microbes can be characterized based on colony appearance, form, elevation, margins, and optical density.
microbial nutrition and growth
This document discusses microbial nutrition and growth. It explains that microbes require nutrients for energy, cellular activities, and constructing new cellular components. The main nutrients include carbon, nitrogen, phosphorus, and trace elements. It categorizes microbes based on their carbon and energy sources. It also describes the physical and chemical requirements for microbial growth, including temperature, pH, oxygen levels, and nutrients. It discusses culture media, methods for measuring growth, and techniques for obtaining pure cultures.
Bacterial anatomy
This document discusses the structure of bacteria. It begins by comparing prokaryotes and eukaryotes, noting key differences such as DNA location, organelles, and ribosomes. It then describes bacteria specifically, including their size, shapes, structures like flagella and cell walls, and differences between gram positive and gram negative bacteria. Important bacterial components are also outlined, such as peptidoglycan, teichoic acids, lipopolysaccharides, and endospores.
isolation and preservation of pure culture
This document discusses various techniques for isolating and preserving pure cultures of microorganisms. It describes common isolation methods like streak plating, pour plating, and spread plating which aim to separate individual microbial cells on a growth medium. Preservation methods to maintain viability for long periods are also outlined, including refrigeration, cryopreservation in liquid nitrogen, storage in sterile soil, overlaying with mineral oil, and lyophilization or freeze drying. Maintaining pure cultures is important for accurate identification and experimentation in microbiology.
Inoculum development.pptx
The document discusses inoculum development and production media for industrial fermentation. It defines inoculum as a culture of microbes used to inoculate production-scale fermentations. Successful fermentations require developing inoculum to an active, healthy state in appropriate density. The document outlines factors that affect fermentation and discusses various media components like carbon sources, nitrogen sources, and trace elements. It also covers inoculum development methods for bacterial and mycelial cultures, preservation techniques, examples of media used for specific inocula, and criteria for a good inoculum.
Viruses, structure, classification and characteristics
The document discusses viruses, defining them as infectious agents that can only multiply within host cells and consist of nucleic acids and protein coats. It covers virus structure, classification, life cycles, methods of transmission between hosts, discovery, theories of origin, and techniques for studying and cultivating viruses. The document provides an overview of the key aspects of virology, including what viruses are, how they spread and reproduce, approaches to classifying them, and historical developments in the field.
General characteristics of viruses
Viruses are submicroscopic infectious agents that can only replicate inside living host cells. They contain nucleic acid surrounded by a protein coat and have no cell structure of their own. Viruses range in size from 20-250nm and are classified based on their nucleic acid type and composition. They are obligate intracellular parasites and depend on host cell machinery for replication. Viruses are cultivated using methods like cell culture, organ culture, and animal inoculation to study their growth and properties. Viral replication involves adsorption, penetration, uncoating, biosynthesis, assembly, and release of new virus particles that infect other host cells.
Bacterial nutrition
Bacteria have various nutritional requirements for growth and reproduction. They require water, a carbon source, nitrogen, inorganic salts, and small amounts of carbon dioxide. Bacteria are classified based on their ability to produce their own organic compounds (autotrophs vs heterotrophs) and use of oxygen (aerobic vs anaerobic). They also have varying temperature, moisture, pH, light, and osmotic pressure requirements. Oxygen requirements further divide bacteria into aerobic, anaerobic, microaerophilic, and facultative anaerobic groups. Most grow best in neutral pH ranges at mesophilic temperatures.
Bacterial growth : Diauxic growth,Synchronous growth and continuous growth
It contain bacterial growth,growth rate and how do it grow?
and,I include Types of continuous growth and their advantages,disadvantages.
Bacterial endospore
Certain gram-positive bacteria like Bacillus and Clostridium can form dormant endospores that are highly resistant to heat, radiation, chemicals and desiccation. Endospores play an important role in food safety and industrial/medical microbiology. An endospore has several protective layers - an outer exosporium, inner spore coat, cortex and core wall surrounding the dormant core. Endospores form through a multi-stage process in response to nutrient depletion. Once activated, endospores germinate and outgrow into active vegetative cells upon exposure to nutrients.
General characters of bacteria and clasification
This document summarizes general characteristics of bacteria, including their typical sizes from 0.1 to 10 micrometers, and shapes such as coccus, bacillus, spirillum, and spirochete. It also describes various ways bacteria can be classified, including by shape, staining properties, oxygen requirements, pH tolerance, temperature tolerance, and osmotic pressure tolerance. Bacteria are widely distributed in environments like soil, air, water, and living bodies, and while some can cause diseases, others are harmless. The document provides examples for each classification method.
Structure of bacterial cell
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.
Method of isolation of pure culture
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.
Recovery and purification of intracellular and extra cellular products
Product recovery and purification, such as centrifugal, chromatography, crystallization, dialysis, drying, electrophoresis, filtration, precipitation, etc., are essential finishing steps to any commercial fermentation process.
PRINCIPLES OF FOOD PRESERVATION SMG
This document outlines the key principles of food preservation:
1) Preventing or delaying microbial decomposition by keeping microorganisms out through packaging and hygienic practices, removing microbes through filtration and washing, and hindering microbial growth through low temperatures, drying, maintaining anaerobic conditions, and using chemical preservatives.
2) Killing microorganisms using heat or irradiation.
3) Preventing self-decomposition of food by blanching to inactivate enzymes and preventing oxidation using antioxidants.
Factors Affecting Microbial Growth
Factors affecting microbial growth include pH, moisture, nutrient content, oxygen, and light. pH is important as most bacteria grow best near neutral pH. Moisture is essential and bacteria require more moisture than yeasts or molds. The nutrient content must provide substances like water, carbon, nitrogen, and minerals for growth. Oxygen levels also impact microbial growth, with some microbes only growing aerobically and others anaerobically. Light is only essential for microbes involved in photosynthesis.
Microbial growth
MICROBIAL GROWTH
SYNOPSIS
INTRODUCTION
REQUIREMENT FOR MICROBIAL GROWTH
PHYSICAL REQUIREMENT
NUTRITIONAL REQUIREMENT
BACTERIAL GROWTH CURVE
FACTORS AFFECTING BACTERIAL GROWTH
COUNTING OF BACTERIAL CELL
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Nutritional requirement by microorganisms
Nutrients are required for microbial growth and act as building blocks and energy sources. The main nutrient requirements for microorganisms include carbon, nitrogen, phosphorus, sulfur, hydrogen, oxygen, potassium, calcium, magnesium, iron and trace elements. Microorganisms can be classified based on their carbon, energy and electron sources as photolithotrophs, photoorganoheterotrophs, chemolithoautotrophs, chemolithoheterotrophs or chemoorganoheterotrophs. Culture media are used to grow microorganisms and include defined, complex, liquid, solid, supportive, enriched, selective and differential media depending on their composition and purpose.
sporulation
This document summarizes the process of sporulation in microorganisms. It describes that spores form as a protective structure during unfavorable conditions and can survive without nutrients. There are two main types of spores - endospores, which form inside the cell, and exospores, which form on the surface. Spores have protective coats, cortex, germ cell wall, and a central core containing DNA. Sporulation is the process where a single cell forms an endospore or exospore, which can later germinate into a new cell under favorable conditions. Key factors like sigma factors regulate genes involved in sporulation and returning to the vegetative state.
Nutritional requirements of microorganisms
The document discusses the basic nutritional requirements of microorganisms. It notes that microbes require nutrients like carbon, hydrogen, nitrogen, oxygen, phosphorus and sulfur for biosynthesis and energy. These nutrients are obtained from both inorganic and organic sources. Microorganisms are also classified based on how they obtain carbon and energy, into four main types: photolithotrophs, photoheterotrophs, chemolithotrophs and chemoheterotrophs. The document provides details on the various microbial growth factors and nutritional types.
pure culture isolation
The document discusses various methods for obtaining pure bacterial cultures, which is necessary for studying individual bacterial species. The key methods are streak plating, pour plating, and spread plating. Streak plating involves streaking bacterial samples on an agar plate to isolate single colonies. Pour plating involves adding a liquid sample to molten agar before pouring into a plate. Spread plating involves spreading a diluted sample evenly on an agar surface. Serial dilution is also used to quantify the original number of bacteria in a sample through successive dilutions.
Pure culture technique
This document discusses techniques for obtaining a pure culture from a mixed culture sample. It explains that a pure culture contains only one type of microorganism, while a mixed culture contains multiple types. The most common laboratory methods for isolating microbes are the streak plate method and pour plate method. Both rely on diluting bacterial cells to a point where single colonies can grow from individual cells. The streak plate method involves transferring a sample to an agar plate using a sterilized loop and streaking the inoculum in sections to separate individual colonies.
Isolation and characterization of microbes
This document discusses the isolation and characterization of microbes. It defines key terms like microbes, pure culture, mixed culture, species, and strain. It describes common methods used to isolate pure cultures from mixed populations, including streak plate technique, micromanipulator method, enrichment culture method, and serial dilution method. The document also discusses maintaining and preserving pure cultures through refrigeration, cryopreservation, and lyophilization. It explains how microbes can be characterized based on colony appearance, form, elevation, margins, and optical density.
microbial nutrition and growth
This document discusses microbial nutrition and growth. It explains that microbes require nutrients for energy, cellular activities, and constructing new cellular components. The main nutrients include carbon, nitrogen, phosphorus, and trace elements. It categorizes microbes based on their carbon and energy sources. It also describes the physical and chemical requirements for microbial growth, including temperature, pH, oxygen levels, and nutrients. It discusses culture media, methods for measuring growth, and techniques for obtaining pure cultures.
Bacterial anatomy
This document discusses the structure of bacteria. It begins by comparing prokaryotes and eukaryotes, noting key differences such as DNA location, organelles, and ribosomes. It then describes bacteria specifically, including their size, shapes, structures like flagella and cell walls, and differences between gram positive and gram negative bacteria. Important bacterial components are also outlined, such as peptidoglycan, teichoic acids, lipopolysaccharides, and endospores.
isolation and preservation of pure culture
This document discusses various techniques for isolating and preserving pure cultures of microorganisms. It describes common isolation methods like streak plating, pour plating, and spread plating which aim to separate individual microbial cells on a growth medium. Preservation methods to maintain viability for long periods are also outlined, including refrigeration, cryopreservation in liquid nitrogen, storage in sterile soil, overlaying with mineral oil, and lyophilization or freeze drying. Maintaining pure cultures is important for accurate identification and experimentation in microbiology.
Inoculum development.pptx
The document discusses inoculum development and production media for industrial fermentation. It defines inoculum as a culture of microbes used to inoculate production-scale fermentations. Successful fermentations require developing inoculum to an active, healthy state in appropriate density. The document outlines factors that affect fermentation and discusses various media components like carbon sources, nitrogen sources, and trace elements. It also covers inoculum development methods for bacterial and mycelial cultures, preservation techniques, examples of media used for specific inocula, and criteria for a good inoculum.
Viruses, structure, classification and characteristics
The document discusses viruses, defining them as infectious agents that can only multiply within host cells and consist of nucleic acids and protein coats. It covers virus structure, classification, life cycles, methods of transmission between hosts, discovery, theories of origin, and techniques for studying and cultivating viruses. The document provides an overview of the key aspects of virology, including what viruses are, how they spread and reproduce, approaches to classifying them, and historical developments in the field.
General characteristics of viruses
Viruses are submicroscopic infectious agents that can only replicate inside living host cells. They contain nucleic acid surrounded by a protein coat and have no cell structure of their own. Viruses range in size from 20-250nm and are classified based on their nucleic acid type and composition. They are obligate intracellular parasites and depend on host cell machinery for replication. Viruses are cultivated using methods like cell culture, organ culture, and animal inoculation to study their growth and properties. Viral replication involves adsorption, penetration, uncoating, biosynthesis, assembly, and release of new virus particles that infect other host cells.
Bacterial nutrition
Bacteria have various nutritional requirements for growth and reproduction. They require water, a carbon source, nitrogen, inorganic salts, and small amounts of carbon dioxide. Bacteria are classified based on their ability to produce their own organic compounds (autotrophs vs heterotrophs) and use of oxygen (aerobic vs anaerobic). They also have varying temperature, moisture, pH, light, and osmotic pressure requirements. Oxygen requirements further divide bacteria into aerobic, anaerobic, microaerophilic, and facultative anaerobic groups. Most grow best in neutral pH ranges at mesophilic temperatures.
Bacterial growth : Diauxic growth,Synchronous growth and continuous growth
It contain bacterial growth,growth rate and how do it grow?
and,I include Types of continuous growth and their advantages,disadvantages.
Bacterial endospore
Certain gram-positive bacteria like Bacillus and Clostridium can form dormant endospores that are highly resistant to heat, radiation, chemicals and desiccation. Endospores play an important role in food safety and industrial/medical microbiology. An endospore has several protective layers - an outer exosporium, inner spore coat, cortex and core wall surrounding the dormant core. Endospores form through a multi-stage process in response to nutrient depletion. Once activated, endospores germinate and outgrow into active vegetative cells upon exposure to nutrients.
General characters of bacteria and clasification
This document summarizes general characteristics of bacteria, including their typical sizes from 0.1 to 10 micrometers, and shapes such as coccus, bacillus, spirillum, and spirochete. It also describes various ways bacteria can be classified, including by shape, staining properties, oxygen requirements, pH tolerance, temperature tolerance, and osmotic pressure tolerance. Bacteria are widely distributed in environments like soil, air, water, and living bodies, and while some can cause diseases, others are harmless. The document provides examples for each classification method.
Structure of bacterial cell
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.
Method of isolation of pure culture
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.
Recovery and purification of intracellular and extra cellular products
Product recovery and purification, such as centrifugal, chromatography, crystallization, dialysis, drying, electrophoresis, filtration, precipitation, etc., are essential finishing steps to any commercial fermentation process.
PRINCIPLES OF FOOD PRESERVATION SMG
This document outlines the key principles of food preservation:
1) Preventing or delaying microbial decomposition by keeping microorganisms out through packaging and hygienic practices, removing microbes through filtration and washing, and hindering microbial growth through low temperatures, drying, maintaining anaerobic conditions, and using chemical preservatives.
2) Killing microorganisms using heat or irradiation.
3) Preventing self-decomposition of food by blanching to inactivate enzymes and preventing oxidation using antioxidants.
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Factors affecting microbial growth include pH, moisture, nutrient content, oxygen, and light. pH is important as most bacteria grow best near neutral pH. Moisture is essential and bacteria require more moisture than yeasts or molds. The nutrient content must provide substances like water, carbon, nitrogen, and minerals for growth. Oxygen levels also impact microbial growth, with some microbes only growing aerobically and others anaerobically. Light is only essential for microbes involved in photosynthesis.
Microbial growth
MICROBIAL GROWTH
SYNOPSIS
INTRODUCTION
REQUIREMENT FOR MICROBIAL GROWTH
PHYSICAL REQUIREMENT
NUTRITIONAL REQUIREMENT
BACTERIAL GROWTH CURVE
FACTORS AFFECTING BACTERIAL GROWTH
COUNTING OF BACTERIAL CELL
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Plant transport systems include xylem and phloem. Xylem transports water and minerals upwards from roots to shoots passively, using no energy. Phloem transports food such as sucrose horizontally throughout the plant using energy from ATP. Xylem vessels are located towards the edges of stems to resist bending forces, while located centrally in roots to withstand stretching. Transpiration is the evaporation of water from plant leaves, powered by the transpiration stream which replaces lost water. Transpiration cools plants and transports minerals upwards from roots.
Atropine
Atropine is an anticholinergic alkaloid found naturally in plants from the Solanaceae family such as deadly nightshade. It acts as an antagonist to acetylcholine by binding to acetylcholine receptors in the nervous system and paralyzing transmission of nerve impulses. This property allows atropine to dilate pupils, increase heart rate by blocking vagus nerve activity, and is used medicinally after heart attacks. Atropine is metabolized in the liver and excreted in urine.
Intro to medical microbiology lecture notes
This document provides an introduction to a course on medical microbiology and immunology. It outlines the objectives of the course which are to provide students with basic knowledge of microorganisms, bacteria of medical importance, aseptic techniques, antimicrobial agents, and basic immunological principles. It also lists the chapter topics to be covered, requirements for students, and staff teaching the course.
Plant Secondary Metabolites
The document discusses secondary metabolite production using plant tissue culture techniques. It describes how secondary metabolites are organic compounds not directly involved in growth that play roles in plant defense. Plant tissue culture and genetic engineering methods can be used to control secondary metabolite production, including manipulating the environment, growth conditions, precursor addition, and transforming plant cells with genes from bacteria like Agrobacterium that influence metabolite pathways. Overall, the document provides an overview of how secondary metabolites are classified and various biotechnological approaches for enhancing their production in plant cell cultures.
Food spoilage
This document discusses food spoilage, which is the process by which food deteriorates to the point of being inedible or having reduced quality of edibility. Spoilage is caused by microbial and biochemical activities and is influenced by intrinsic factors like pH and nutrients, and extrinsic factors like temperature and humidity. Different foods like fruits, vegetables, cereals, milk, meat, fish, eggs and canned foods are subject to spoilage by various microbes under different conditions. Food preservation methods aim to stop or slow spoilage by killing microbes or preventing their growth in order to maintain food safety and nutrition.
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The document discusses plant growth and development. It defines growth as a permanent increase in plant mass through cell division and enlargement. Growth occurs in phases including formation, elongation, and maturation. Development includes differentiation, where cells take on specialized structures and functions. The document also discusses leaf growth, flowering, pollination, fertilization, seed formation, and fruit development. Environmental factors and phytohormones influence growth and developmental processes.
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The document discusses the benefits of exercise for mental health. Regular physical activity can help reduce anxiety and depression and improve mood and cognitive function. Exercise causes chemical changes in the brain that may help protect against mental illness and improve symptoms.
physiology : the nervous system
The document summarizes the structure and function of the nervous system. It consists of the central nervous system (CNS), made up of the brain and spinal cord, and the peripheral nervous system (PNS), made up of nerves. The CNS processes sensory information and motor commands, while the PNS connects the CNS to sensory receptors and muscles. Communication occurs via neurons, which transmit electrochemical signals through synapses using neurotransmitters.
physiology : muscular system
1. The muscular system contains three main types of muscles - skeletal, cardiac, and smooth muscles. Skeletal muscles are voluntary and attach to bones to enable movement, cardiac muscles are involuntary and found in the heart, and smooth muscles are involuntary and found in organs and blood vessels.
2. Skeletal muscles contain repeating contractile units called sarcomeres composed of the proteins actin and myosin. The sliding of actin over myosin forms cross-bridges that cause muscle contraction.
3. Contraction is initiated by a neural impulse causing calcium release and the binding of calcium to troponin, exposing actin binding sites on the myosin heads to generate force through cross-bridge cycling. Relax
physiology : Excretion
This document discusses the principles of physiology, focusing on the urinary system. It describes the key functions of the kidneys as excretion of wastes, regulation of homeostasis, and secretion of substances like rennin and erythropoietin. The basic structures and functions of nephrons are explained, including the three stages of filtration, reabsorption and secretion in urine formation. Various conditions that can impact urine output like diabetes and kidney diseases are also summarized.
physiology
This document discusses nutrition and the essential nutrients required by the human body. It defines nutrition and describes the major nutrients - carbohydrates, lipids, proteins, vitamins and minerals. It provides details on the classification, sources and biological significance of each nutrient. The balanced diet is emphasized as one that contains carbohydrates, lipids, proteins, vitamins and minerals in proper amounts.
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This document provides information about Dr. Adel Ahmed Ali El-Morsi's educational background and qualifications. It then discusses various topics related to general microbiology, including controlling microorganisms through physical and chemical agents, terminology used in microbial control, targets of antimicrobial agents, factors affecting efficacy, and specific physical control methods like heat.
Lect. 3 (microbial nutrition and cultivation)
Microbial growth conditions depend on various nutrients and environmental factors. Microorganisms require macronutrients like carbon, nitrogen, phosphorus and micronutrients in small amounts. They also need growth factors like vitamins and amino acids. Temperature, pH, and oxygen levels influence microbial growth. Pure cultures can be isolated using techniques like streak plating that allow single microbial cells to grow into separate colonies.
Lect. 2 (economic significance of microorganisms)
Microorganisms, which are only visible under a microscope, play both beneficial and harmful roles. Beneficially, they fix nitrogen in soil, decompose organic waste to recycle nutrients, produce antibiotics, and aid in food production and sewage treatment. However, some microbes cause infectious diseases in humans and plants. Pathogenic bacteria and viruses can directly damage tissues or produce toxins. Diseases are controlled through prevention, treatment, and food preservation methods that kill microorganisms or stop their growth.
Lect. 1 introduction to general microbiology
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