morphology & structure of spirochete, fungi & protozoa
Microbiology (Doctor of Medicine course) for Virology discipline in Medicine by Sanskar Virmani, at School of Medicine, V. N. Karazin Kharkiv National University, Kharkiv, Ukraine.
Presentation is free to use for non-monetary purposes if the author (i.e., me) is properly cited and given due credits.
LinkedIn Profile: bit.ly/SanskarV_LinkedIn
An introduction to Medical Parasitologyrinki singh
Medical parasitology: “the study and medical implications of parasites that infect humans”. A parasite: “a living organism that acquires some of its basic ...
An introduction to Medical Parasitologyrinki singh
Medical parasitology: “the study and medical implications of parasites that infect humans”. A parasite: “a living organism that acquires some of its basic ...
Helminths in adult population in countries.pptxbarakaakute
This is a presentation on helminths in various population groups around the world. Broadly, the term "helminth" refers to parasitic worms that can be classified into 2 phyla: Nematoda (roundworms) and Platyhelminthes (flatworms). The phylum Platyhelminthes is further divided into Cestoda (tapeworms) and Trematoda (flukes).
Helminthiasis is a major public health threat throughout Asia, sub-Saharan Africa, and the Americas. It has been estimated that more than 1 billion people worldwide are infected with at least 1 species, and many are coinfected with 2 or more parasites.[3,4] Most of those affected represent the world's poorest and most vulnerable populations. Economist Paul Collier has termed this population "the bottom billion." Poor access to healthcare, sanitation, and clean water make this group particularly susceptible to infection.
This article will discuss how helminth infections affect arguably the most vulnerable group of all: neonates and young children.
In this first case, both EB and his mother demonstrate consequences of hookworm infection. Two species of hookworm cause disease in humans. Necator americanus is found in the Americas, sub-Saharan Africa, and parts of Asia. A duodenale occurs in the Mediterranean, parts of the Middle East, and Asia. Between 740 million and 1.3 billion people worldwide are probably infected.[2,5]
Hookworm eggs are found in soil contaminated with feces. The larvae hatch, develop in the soil, and penetrate the skin of a human host. As the larvae migrate through the host's skin, a pruritic rash may erupt. The larvae then travel through the bloodstream to the lungs, where they penetrate the alveoli and are swallowed by the host. They mature in the small intestine, where the main manifestations of disease occur. The parasite's mouthpiece contains sharp hooks for attaching to the duodenal wall. Once attached, hookworms release anticoagulant peptides and serine proteinase inhibitors, which contribute to anemia and malabsorption of nutrients, respectively.
After attachment, a single worm may consume 0.3-0.5 mL of blood per day.[6,7] Heavy infection can therefore result in profound anemia as well as protein loss, leading to malnutrition and anasarca. In endemic areas, coinfection with multiple types of helminthes is common and increases nutritional losses.
In general, helminth infections are more common in children than in young infants. Nevertheless, maternal infection is common and can profoundly affect neonatal health. In the case of EB, his mother had a history of anemia and a previous preterm delivery.
Iron-deficiency anemia induced by hookworms poses particular problems for pregnant, breastfeeding, or menstruating women, who have increased iron demands. Iron-deficiency anemia during pregnancy is a known risk factor for intrauterine growth restriction, low birthweight, preterm birth, and low neonatal iron stores.[4,8,9] In areas with poor resources to care for preterm or low-birthweight infants.
Introduction to Mycology 2020 (2).pptxDawn Junkere
shows the different fungal infections human can be exposed to. how medical treatment can be carried out to treat
use of antofungals. the different parts of the fungus
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
More Related Content
Similar to morphology & structure of spirochete, fungi & protozoa
Helminths in adult population in countries.pptxbarakaakute
This is a presentation on helminths in various population groups around the world. Broadly, the term "helminth" refers to parasitic worms that can be classified into 2 phyla: Nematoda (roundworms) and Platyhelminthes (flatworms). The phylum Platyhelminthes is further divided into Cestoda (tapeworms) and Trematoda (flukes).
Helminthiasis is a major public health threat throughout Asia, sub-Saharan Africa, and the Americas. It has been estimated that more than 1 billion people worldwide are infected with at least 1 species, and many are coinfected with 2 or more parasites.[3,4] Most of those affected represent the world's poorest and most vulnerable populations. Economist Paul Collier has termed this population "the bottom billion." Poor access to healthcare, sanitation, and clean water make this group particularly susceptible to infection.
This article will discuss how helminth infections affect arguably the most vulnerable group of all: neonates and young children.
In this first case, both EB and his mother demonstrate consequences of hookworm infection. Two species of hookworm cause disease in humans. Necator americanus is found in the Americas, sub-Saharan Africa, and parts of Asia. A duodenale occurs in the Mediterranean, parts of the Middle East, and Asia. Between 740 million and 1.3 billion people worldwide are probably infected.[2,5]
Hookworm eggs are found in soil contaminated with feces. The larvae hatch, develop in the soil, and penetrate the skin of a human host. As the larvae migrate through the host's skin, a pruritic rash may erupt. The larvae then travel through the bloodstream to the lungs, where they penetrate the alveoli and are swallowed by the host. They mature in the small intestine, where the main manifestations of disease occur. The parasite's mouthpiece contains sharp hooks for attaching to the duodenal wall. Once attached, hookworms release anticoagulant peptides and serine proteinase inhibitors, which contribute to anemia and malabsorption of nutrients, respectively.
After attachment, a single worm may consume 0.3-0.5 mL of blood per day.[6,7] Heavy infection can therefore result in profound anemia as well as protein loss, leading to malnutrition and anasarca. In endemic areas, coinfection with multiple types of helminthes is common and increases nutritional losses.
In general, helminth infections are more common in children than in young infants. Nevertheless, maternal infection is common and can profoundly affect neonatal health. In the case of EB, his mother had a history of anemia and a previous preterm delivery.
Iron-deficiency anemia induced by hookworms poses particular problems for pregnant, breastfeeding, or menstruating women, who have increased iron demands. Iron-deficiency anemia during pregnancy is a known risk factor for intrauterine growth restriction, low birthweight, preterm birth, and low neonatal iron stores.[4,8,9] In areas with poor resources to care for preterm or low-birthweight infants.
Introduction to Mycology 2020 (2).pptxDawn Junkere
shows the different fungal infections human can be exposed to. how medical treatment can be carried out to treat
use of antofungals. the different parts of the fungus
Title: Sense of Smell
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the primary categories of smells and the concept of odor blindness.
Explain the structure and location of the olfactory membrane and mucosa, including the types and roles of cells involved in olfaction.
Describe the pathway and mechanisms of olfactory signal transmission from the olfactory receptors to the brain.
Illustrate the biochemical cascade triggered by odorant binding to olfactory receptors, including the role of G-proteins and second messengers in generating an action potential.
Identify different types of olfactory disorders such as anosmia, hyposmia, hyperosmia, and dysosmia, including their potential causes.
Key Topics:
Olfactory Genes:
3% of the human genome accounts for olfactory genes.
400 genes for odorant receptors.
Olfactory Membrane:
Located in the superior part of the nasal cavity.
Medially: Folds downward along the superior septum.
Laterally: Folds over the superior turbinate and upper surface of the middle turbinate.
Total surface area: 5-10 square centimeters.
Olfactory Mucosa:
Olfactory Cells: Bipolar nerve cells derived from the CNS (100 million), with 4-25 olfactory cilia per cell.
Sustentacular Cells: Produce mucus and maintain ionic and molecular environment.
Basal Cells: Replace worn-out olfactory cells with an average lifespan of 1-2 months.
Bowman’s Gland: Secretes mucus.
Stimulation of Olfactory Cells:
Odorant dissolves in mucus and attaches to receptors on olfactory cilia.
Involves a cascade effect through G-proteins and second messengers, leading to depolarization and action potential generation in the olfactory nerve.
Quality of a Good Odorant:
Small (3-20 Carbon atoms), volatile, water-soluble, and lipid-soluble.
Facilitated by odorant-binding proteins in mucus.
Membrane Potential and Action Potential:
Resting membrane potential: -55mV.
Action potential frequency in the olfactory nerve increases with odorant strength.
Adaptation Towards the Sense of Smell:
Rapid adaptation within the first second, with further slow adaptation.
Psychological adaptation greater than receptor adaptation, involving feedback inhibition from the central nervous system.
Primary Sensations of Smell:
Camphoraceous, Musky, Floral, Pepperminty, Ethereal, Pungent, Putrid.
Odor Detection Threshold:
Examples: Hydrogen sulfide (0.0005 ppm), Methyl-mercaptan (0.002 ppm).
Some toxic substances are odorless at lethal concentrations.
Characteristics of Smell:
Odor blindness for single substances due to lack of appropriate receptor protein.
Behavioral and emotional influences of smell.
Transmission of Olfactory Signals:
From olfactory cells to glomeruli in the olfactory bulb, involving lateral inhibition.
Primitive, less old, and new olfactory systems with different path
Tom Selleck Health: A Comprehensive Look at the Iconic Actor’s Wellness Journeygreendigital
Tom Selleck, an enduring figure in Hollywood. has captivated audiences for decades with his rugged charm, iconic moustache. and memorable roles in television and film. From his breakout role as Thomas Magnum in Magnum P.I. to his current portrayal of Frank Reagan in Blue Bloods. Selleck's career has spanned over 50 years. But beyond his professional achievements. fans have often been curious about Tom Selleck Health. especially as he has aged in the public eye.
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Introduction
Many have been interested in Tom Selleck health. not only because of his enduring presence on screen but also because of the challenges. and lifestyle choices he has faced and made over the years. This article delves into the various aspects of Tom Selleck health. exploring his fitness regimen, diet, mental health. and the challenges he has encountered as he ages. We'll look at how he maintains his well-being. the health issues he has faced, and his approach to ageing .
Early Life and Career
Childhood and Athletic Beginnings
Tom Selleck was born on January 29, 1945, in Detroit, Michigan, and grew up in Sherman Oaks, California. From an early age, he was involved in sports, particularly basketball. which played a significant role in his physical development. His athletic pursuits continued into college. where he attended the University of Southern California (USC) on a basketball scholarship. This early involvement in sports laid a strong foundation for his physical health and disciplined lifestyle.
Transition to Acting
Selleck's transition from an athlete to an actor came with its physical demands. His first significant role in "Magnum P.I." required him to perform various stunts and maintain a fit appearance. This role, which he played from 1980 to 1988. necessitated a rigorous fitness routine to meet the show's demands. setting the stage for his long-term commitment to health and wellness.
Fitness Regimen
Workout Routine
Tom Selleck health and fitness regimen has evolved. adapting to his changing roles and age. During his "Magnum, P.I." days. Selleck's workouts were intense and focused on building and maintaining muscle mass. His routine included weightlifting, cardiovascular exercises. and specific training for the stunts he performed on the show.
Selleck adjusted his fitness routine as he aged to suit his body's needs. Today, his workouts focus on maintaining flexibility, strength, and cardiovascular health. He incorporates low-impact exercises such as swimming, walking, and light weightlifting. This balanced approach helps him stay fit without putting undue strain on his joints and muscles.
Importance of Flexibility and Mobility
In recent years, Selleck has emphasized the importance of flexibility and mobility in his fitness regimen. Understanding the natural decline in muscle mass and joint flexibility with age. he includes stretching and yoga in his routine. These practices help prevent injuries, improve posture, and maintain mobilit
- 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.
Local Advanced Lung Cancer: Artificial Intelligence, Synergetics, Complex Sys...Oleg Kshivets
Overall life span (LS) was 1671.7±1721.6 days and cumulative 5YS reached 62.4%, 10 years – 50.4%, 20 years – 44.6%. 94 LCP lived more than 5 years without cancer (LS=2958.6±1723.6 days), 22 – more than 10 years (LS=5571±1841.8 days). 67 LCP died because of LC (LS=471.9±344 days). AT significantly improved 5YS (68% vs. 53.7%) (P=0.028 by log-rank test). Cox modeling displayed that 5YS of LCP significantly depended on: N0-N12, T3-4, blood cell circuit, cell ratio factors (ratio between cancer cells-CC and blood cells subpopulations), LC cell dynamics, recalcification time, heparin tolerance, prothrombin index, protein, AT, procedure type (P=0.000-0.031). Neural networks, genetic algorithm selection and bootstrap simulation revealed relationships between 5YS and N0-12 (rank=1), thrombocytes/CC (rank=2), segmented neutrophils/CC (3), eosinophils/CC (4), erythrocytes/CC (5), healthy cells/CC (6), lymphocytes/CC (7), stick neutrophils/CC (8), leucocytes/CC (9), monocytes/CC (10). Correct prediction of 5YS was 100% by neural networks computing (error=0.000; area under ROC curve=1.0).
micro teaching on communication m.sc nursing.pdfAnurag Sharma
Microteaching is a unique model of practice teaching. It is a viable instrument for the. desired change in the teaching behavior or the behavior potential which, in specified types of real. classroom situations, tends to facilitate the achievement of specified types of objectives.
Title: Sense of Taste
Presenter: Dr. Faiza, Assistant Professor of Physiology
Qualifications:
MBBS (Best Graduate, AIMC Lahore)
FCPS Physiology
ICMT, CHPE, DHPE (STMU)
MPH (GC University, Faisalabad)
MBA (Virtual University of Pakistan)
Learning Objectives:
Describe the structure and function of taste buds.
Describe the relationship between the taste threshold and taste index of common substances.
Explain the chemical basis and signal transduction of taste perception for each type of primary taste sensation.
Recognize different abnormalities of taste perception and their causes.
Key Topics:
Significance of Taste Sensation:
Differentiation between pleasant and harmful food
Influence on behavior
Selection of food based on metabolic needs
Receptors of Taste:
Taste buds on the tongue
Influence of sense of smell, texture of food, and pain stimulation (e.g., by pepper)
Primary and Secondary Taste Sensations:
Primary taste sensations: Sweet, Sour, Salty, Bitter, Umami
Chemical basis and signal transduction mechanisms for each taste
Taste Threshold and Index:
Taste threshold values for Sweet (sucrose), Salty (NaCl), Sour (HCl), and Bitter (Quinine)
Taste index relationship: Inversely proportional to taste threshold
Taste Blindness:
Inability to taste certain substances, particularly thiourea compounds
Example: Phenylthiocarbamide
Structure and Function of Taste Buds:
Composition: Epithelial cells, Sustentacular/Supporting cells, Taste cells, Basal cells
Features: Taste pores, Taste hairs/microvilli, and Taste nerve fibers
Location of Taste Buds:
Found in papillae of the tongue (Fungiform, Circumvallate, Foliate)
Also present on the palate, tonsillar pillars, epiglottis, and proximal esophagus
Mechanism of Taste Stimulation:
Interaction of taste substances with receptors on microvilli
Signal transduction pathways for Umami, Sweet, Bitter, Sour, and Salty tastes
Taste Sensitivity and Adaptation:
Decrease in sensitivity with age
Rapid adaptation of taste sensation
Role of Saliva in Taste:
Dissolution of tastants to reach receptors
Washing away the stimulus
Taste Preferences and Aversions:
Mechanisms behind taste preference and aversion
Influence of receptors and neural pathways
Impact of Sensory Nerve Damage:
Degeneration of taste buds if the sensory nerve fiber is cut
Abnormalities of Taste Detection:
Conditions: Ageusia, Hypogeusia, Dysgeusia (parageusia)
Causes: Nerve damage, neurological disorders, infections, poor oral hygiene, adverse drug effects, deficiencies, aging, tobacco use, altered neurotransmitter levels
Neurotransmitters and Taste Threshold:
Effects of serotonin (5-HT) and norepinephrine (NE) on taste sensitivity
Supertasters:
25% of the population with heightened sensitivity to taste, especially bitterness
Increased number of fungiform papillae
Basavarajeeyam is an important text for ayurvedic physician belonging to andhra pradehs. It is a popular compendium in various parts of our country as well as in andhra pradesh. The content of the text was presented in sanskrit and telugu language (Bilingual). One of the most famous book in ayurvedic pharmaceutics and therapeutics. This book contains 25 chapters called as prakaranas. Many rasaoushadis were explained, pioneer of dhatu druti, nadi pareeksha, mutra pareeksha etc. Belongs to the period of 15-16 century. New diseases like upadamsha, phiranga rogas are explained.
Basavarajeeyam - Ayurvedic heritage book of Andhra pradesh
morphology & structure of spirochete, fungi & protozoa
1.
2. The phylum Spirochaetes (Greek spira, a
coil, and chaete, hair) contains gram-
negative, chemoheterotrophic bacteria
distinguished by their structure and
mechanism of motility.
They are slender, long bacteria (0.1 to 3.0 μm
by 5 to 250 μm) with a flexible, helical shape.
3. The Spirochetes. Representative examples. (a) Cristispira sp. from a clam;
phase contrast ( 2,200). (c) Leptospira interrogans (2,200).
5. Many species are so slim that they are only clearly
visible in a light microscope by means of phase-
contrast or dark-field optics.
Spirochetes differ greatly from other bacteria with
respect to motility and can move through very
viscous solutions though they lack external rotating
flagella.
When in contact with a solid surface, they exhibit
creeping or crawling movements. Their unique
pattern of motility is due to an unusual
morphological structure called the axial filament.
6. The axial fibrils or periplasmic flagella are visible around the protoplasmic
cylinder (6,000).
7. The central protoplasmic cylinder contains
cytoplasm and the nucleoid, and is bounded
by a plasma membrane and a gram-negative
cell wall. Two to more than a hundred
flagella, called axial fibrils, periplasmic
flagella, or endoflagella, extend from both
ends of the cylinder and often overlap one
another in the center third of the cell.
8. The most distinctive characteristic of this order,
however, is their method of motility, which
makes use of two or more axial filaments (or
endoflagella) enclosed in the space between an
outer sheath and the body of the cell. One end
of each axial filament is attached near a pole of
the cell. By rotating its axial filament, the cell
rotates in the opposite direction, like a
corkscrew, which is very efficient in moving the
organism through liquids.
9.
10. Bacterium can typically move about 100
times its body length in a second (or about
50 ), whereas a large fish, such as a tuna,
can move only about 10 times its body
length in this time.
11. Many spirochetes are found in the human
oral cavity and are probably among the first
microorganisms described by van
Leeuwenhoek in the 1600s that he found in
saliva and tooth scrapings.
12. The spirochetes include a number of
important pathogenic bacteria . The best
known is the genus Treponema (tre-po-
ne'mii), which includes Treponema pallidum
(pal'li-dum), the cause of syphilis.
13.
14. Borrelia Members of the genus Borrelia
(bor'rel-e-a) cause relapsing fever and Lyme
disease, serious diseases that are usually
transmitted by ticks or lice.
15. Leptospirosis is a disease usually spread to
humans by water contaminated by
Leptospira (lep-to-spi' ra) species.
The bacteria are excreted in the urine of
such animals as dogs, rats, and swine, so
domestic dogs and cats are routinely
immunized against leptospirosis.
16. The common characteristic of being obligate
intracellular parasites-that is, they reproduce
only within a mammalian cell. The rickettsias
are gram-negative rod-shaped bacteria, or
coccobacilli.
One distinguishing feature of most
rickettsias is that they are transmitted to
humans by bites of insects and ticks.
17. Rickettsias grow only within a host cell. such as the chicken embryo cell
shown here. Note the scattered rickettsias within the cell and the compact
masses 01 rickettsias in the cell nucleus.
18. Rickettsia enter their host cell by inducing
phagocytosis. They quickly enter the cytoplasm of
the cell and begin reproducing by binary fission .
They can usually be cultivated artificially in cell
culture or chick embryos The rickettsias are
responsible for a number of diseases known as the
spotted fever group. These include epidemic
typhus, caused by Rickettsia prowazekii (ri -ket'se-a
prou-wa-ze' ke-e) and transmitted by lice; endemic
murine typhus, caused by R. typhi (ti 'Ie ) and
transmitted by rat fleas; and Rocky Mountain
spotted fever, caused by R. rickettsii (ri -ket 'se-e)
and transmitted by ticks.
In humans, rickettsial infections damage the
permeability of blood capillaries, which results in a
characteristic spotted rash.
19. The mycoplasmas are highly pleomorphic
because they lack a cell wall and can
produce filaments that resemble fungi, hence
their name mykes = fungus, and plasma
=formed ).
20. Mycoplasma pneumoniae. Bacteria such as M.
pneumonrae have no cell walls, and their
morphology is irregular (pleomorphic]
21. Cells of the genus Mycoplasma (mi-ko-plaz'ma)
are very small, ranging in size from 0.1 to 0,25
μm, with a cell volume that is only about 5% of
that of a typical bacillus. Because their size and
plasticity allowed them to pass through filters
that retained bacteria, they were originally
considered to be viruses.
Mycoplasmas may represent the smallest self-
replicating organisms that are capable of a free-
living existence.
22.
23. The most significant human pathogen among the
mycoplasmas is M. pneumoniae (nu-mo'ne-I),
which is the cause of a common form of mild
pneumonia. Other genera in the order
Mycoplasmatales are Spiroplasma (spi-ro-plaz'ma),
cells with a tight corkscrew morphology that are
serious plant pathogens and common parasites of
plant-feeding insects, and Ureaplasma (u-re-a-
plaz'ma), so named because they can
enzymatically hydrolyze the urea in urine and are
occasionally associated with urinary tract infections.
24. Members of the phylum Chlamydiae are
grouped with other genetically similar
bacteria that do not contain peptidoglycan in
their cell walls.
25. Chlamydia and Chlamydophila which we will
call by the common name of the chlamydias,
have a unique developmental cycle that is
perhaps their most distinguishing
characteristic.
26.
27. They are gram-negative coccoid bacteria.
The elementary body shown is the infective
agent. Unlike the rickettsias, chlamydias do
not require insects or ticks for transmission .
They are transmitted to humans by
interpersonal contact or byairborne
respiratory routes.
28. Micrograph of Chlamydophilla in the cytoplasm of a host cell.
The elementary bodies are the infectious stage; they are dense, dark,
and relatively small. Reticulate bodies, the form in which chlamydias
reproduce within the host cell , are larger with a speckled appearance.
Intermediate bodies, a stage between the two, have a dark center.
29. There are three species of the chlamydias that are
significant pathogens for humans. Chlamydia
trachomatis (kla-mi'de-a tra -ka'ma -tis) is the best
known pathogen of the group and responsible for
more than one major disease. These include
trachoma, one of the most common causes of
blindness in humans in the less developed
countries. It is also considered to be the primary
causative agent of both nongonococcal urethritis,
which may be the most common sexually
transmitted disease, and lymphogranuloma
venereum, another sexually transmitted disease.
30.
31. The genera Streptomyces, Frankia,
Actinomyces, and Nocardia are often
informally called actinomycetes (from the
Greek actina = ray) because they have a
radiate, or starlike, form of growth by reason
of their often-branching filaments.
32. Superficially, their morphology resembles
that of filamentous fungi; however, the
actinomycetes are prokaryotic cells, and
their filaments have a diameter much smaller
than that of the eukaryotic molds.
Some actinomycetes further resemble molds
by their possession of externally carried
asexual spores that are used for
reproduction.
33. The actinomycetes are a fascinating group of
microorganisms.
They are the source of most of the antibiotics
used in medicine today.
They also produce metabolites that are used
as anticancer drugs, antihelminthics and
drugs that suppress the immune system in
patients who have received organ
transplants.
34. The life cycle of many actinomycetes includes
the development of filamentous cells, called
hyphae, and spores. When growing on a
solid substratum such as soil or agar, the
actinomycetes develop a branching network of
hyphae.
The hyphae grow both on the surface of the
substratum and into it to form a dense mat of
hyphae termed a substrate mycelium. Septae
usually divide the hyphae into long cells (20
μm and longer) containing several nucleoids.
35.
36. In many actinomycetes, substrate hyphae
differentiate into upwardly growing hyphae to
form an aerial mycelium that extends above
the substratum. The aerial hyphae form thin-
walled spores upon septation. These spores
are considered exospores because they do
not develop within a mother cell like the
endospores of Bacillus and Clostridium.
If the spores are located in a sporangium,they
may be called sporangiospores.
37. Representatives of the Genus Actinomyces.
(a) A. naeslundii; Gram stain (1,000). (b) Actinomyces; scanning
electron micrograph (18,000). Note filamentous nature of the
colony.
38. All fungi are chemoheterotrophs, requiring
organic compounds for energy and carbon.
Fungi are aerobic or facultatively anaerobic;
only a few anaerobic fungi are known.
39.
40. Fungal colon ies are described as vegetative
structures because they are composed of
the cells involved in catabolism and growth.
The thallus (body) of a mold or fleshy fungus
consists of long filaments of cells joined
together; these filam ents are called hyphae
(singular: hypha) .
41. In most molds, the hyphae contain cross-
walls called septa (singular: septum), which
divide them in to distinct, uninucleate (one-
nucleus) cell-like units.
These hyphae are called septate hyphae. In
a few classes of fungi , the hyphae contain
no septa and appear as long, continuous
cells with many nuclei.These are called
coenocytic hyphae.
42.
43. The portion of a hypha that obtains nutrients is called the
vegetative hypha; the portion concerned with reproduction is the
reproductive or aerial hypha, so named because it projects
above the surface of the medium on which the fungus is
growing.
Aerial hyphae often bear reproductive spores. When
environmental conditions are suitable, the hyphae grow to form
a filamentous mass called a mycelium, which is visible to the
unaided eye.
44. Yeasts are nonfilamentous, unicellular fungi that are
typically spherical or oval. Budding yeasts, such as
Saccharomyces (sak-a- ro -mi'ses), divide
unevenly. In budding, the parent cell forms a
protuberance (bud) on its outer surface. As the bud
elongates, the parent cell's nucleus divides, and
one nucleus migrates into the bud. Cell wall
material is then laid down between the bud and
parent cell , and the bud eventually breaks away.
45. One yeast cell can in time produce up to 24
daughter cells by budding. Some yeasts
produce buds that fail to detach themselves;
these buds form a short chain of cells called
a pseudohypha. Candida albicans (kan'did-
a al'bi-kanz) attaches to human epithelial
cells as a yeast but usually requires
pseudohyphae to invade deeper tissues.
46. Fission yeasts, such as Sacchoromyces , divide
evenly to produce two new cells. During fission,
the parent cell elongates, its nucleus divides,
and two daughter cells are produced. Increases
in the number of yeast cells on a solid medium
produce a colony similar to a bacterial colony.
Saccharomyces species produce ethanol in
brewed beverages and carbon dioxide for
leavening bread dough.
47. Some fungi, most notably the pathogenic species, exhibit
dimorphism-two forms of growth. Such fungi can grow
either as a mold or as a yeast. The moldlike forms produce
vegetative and aerial hyphae; the yeastlike forms
reproduce by budding.
Dimorphism in pathogenic fungi is temperature dependent:
at 37C, the fungus is yeastlike, and at 25°C, it is moldlike.
48. Filamentous fungi can reproduce asexually by fragmentation of
their hyphae. In addition, both sexual and asexual reproduction
in fungi occurs by the formation of spores. Fungal spores can
be either asexual or sexual.
Asexual spores are formed by the hyphae of one organism.
When these spores germinate, they become organisms that are
genetically identical to the parent.
Sexual spores result from the fusion of nuclei from two opposite
mating strains of the same species of fungus.
Fungi produce sexual spores less frequently than asexual
spores. Organisms that grow from sexual spores will have
genetic characteristics of both parental strains.
49. Asexual spores are produced by an individual
fungus through mitosis and subsequent cell
division; there is no fusion of the nuclei of cells.
Two types of asexual spores are produced by
fungi .
One type is a conidiospore, or conidium
(plural : conidia), a unicellular or multicellular
spore that is not enclosed in a sac. Conidia are
produced in a chain at the end of a
conidiophore. Such spores are produced by
Aspergillus (a-sper-jil'lus).
50. Conidia formed by the fragmentation of a
septate hypha into single, slightly thickened
cells are called arthroconidia. One species
that produces such spores is Coccidioides
immitis.
51. Another type of conidium, blastoconidia,
consists of buds coming off the parent cell.
Such spores are found in some yeasts, such
as Candida albicans and Cryptococcus.
52. A chlamydoconidium is a thick-walled spore
formed by rounding and enlargement within
a hyphal segment. A fungus that produces
chlamydoconidia is the yeast C. albicans.
53. The other type of asexual spore is a
sporangiospore, formed within a sporangium,
or sac, at the end of an aerial hypha called a
sporangiophore. The sporangium can contain
hundreds of sporangiospores. Such spores are
produced by Rhizopus.
54. A fungal sexual spore results from sexual reproduction,
which consists of three phases:
I. Plasmogamy. A haploid nucleus of a donor cell (+)
penetrates the cytoplasm of a recipient cell (-).
2. Karyogamy. The (+) and (-) nuclei fuse to form a diploid
zygote nucleus.
3. Meiosis. The diploid nucleus gives rise to haploid nuclei
(sexual spores), some of which may be genetic
recombinants.
The sexual spores produced by fungi characterize the
phyla.
In laboratory settings, most fungi exhibit only asexual
spores. Consequently, clinical identification is based on
microscopic examination of asexual spores.
55.
56. Any fungal infection is called a mycosis.
Mycoses are generally chronic (long-lasting)
infections because fungi grow slowly. Mycoses
are classified into five groups according to the
degree of tissue involvement and mode of entry
into the host: systemic, subcutaneous,
cutaneous, superficial, or opportunistic. Fungi
are related to animals. Consequently, drugs that
affect fungal cells may also affect animal cells.
This fact makes fungal infections of humans
and other animals often difficult to treat.
57.
58. Protozoa are unicellular, eukaryotic
chemoheterotrophic organisms. Among the
protozoa are many variations on this cell
structure. The term protozos means "first
animal," which generally describes its
animal-like nutrition. In addition to getting
food, a protozoan must reproduce, and
parasitic species must be able to get from
one host to another.
59. Protozoa reproduce asexually by fission, budding, or schizogony.
Schizogony is multiple fission; the nucleus undergoes multiple
divisions before the cell divides. After many nuclei are formed, a small
portion of cytoplasm concentrates around each nucleus, and then the
single cell separates into daughter cells.
Sexual reproduction has been observed in some protozoa.
The ciliates, such as Paramecium, reproduce sexually by conjugation,
which is very different from the bacterial process of the same name.
During protozoan conjugation, two cells fuse, and a haploid nucleus
(the micronucleus) from each cell migrates to the other cell. This
haploid micronucleus fuses with the haploid micronucleus within the
cell. The parent cells separate, each now a fertilized cell. When the
cells later divide, they produce daughter cells with recombined DNA.
Some protozoa produce gametes (gametocytes), haploid sex cells.
During reproduction, two gametes fuse to form a diploid zygote.
60.
61. Protozoa are mostly aerobic heterotrophs, although many
intestinal protozoa are capable of anaerobic growth. Two
chlorophyllcontaining groups, dinoflagellates and euglenoids,
are often studied with algae.
All protozoa live in areas with a large supply of water. Some
protozoa transport food across the plasma membrane. However,
some have a protective covering, or pellicle, and thus require
specialized structures to take in food.
Ciliates take in food by waving their cilia toward a mouthlike
opening called a cytostome.
Amoebas engulf food by surrounding it with pseudopods and
phagocytizing it.
In all protozoa, digestion takes place in membrane-enclosed
vacuoles, and waste may be eliminated through the plasma
membrane or through a specialized anal pore.
62. Ciliates_(a) Paramecium is covered with rows of cilia. It has specialized structures
for ingestion (mouth). elimination of wastes (anal pore), and the regulation of
osmotic pressure (contractile vacuoles). The macronucleus is involved with protein
synthesis and other ongoing cellular activities. The micronucleus functions in
sexual reproduction.
(b) Voricella attaches to objects in water by the base of its stalk. The
springlike stalk can expand al lowing Vorticella to feed in different areas.
Cilia surround its cytostome.
63. Amoebozoa. (a) To move and to engulf food. Amoebas (such as this Amoeba
proteus) extend cytoplasmic structures called pseudopods. Food vacuoles are
created when pseudopods surround food and bring it into the cell.
(b) Entamoeba histolytica. The presence of ingested red blood cells is
diagnostic for Entamoeba
64. Archaezoa. (a) Chilomastix. This
flagellate. found in the human intestine.
may be mildly pathogenic. The cysts
survive for months
outside a human host. The fourth
flagellum is used to move food into the
oral groove. where food vacuoles are
formed.
(b) Trichomonas vaginalis.
This flagelate causes urinary and genital
tract infections. Notice the small
undulating membrane.