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.
B cell Activation by T Independent & T Dependent Antigens-Dr C R MeeraMeera C R
During humoral immune response, Ab production is brought about by B lymphocytes. Based on the ability to induce Ab formation, antigens can be classified into T independent and T dependent antigens. Some antigens can directly induce the B cells to produce the Abs and are called T Independent Ans. However, some Ans require the help of T lymohocytes for the production of Abs from B cells. These Ans are called T Dependent Ans.
B cell Activation by T Independent & T Dependent Antigens-Dr C R MeeraMeera C R
During humoral immune response, Ab production is brought about by B lymphocytes. Based on the ability to induce Ab formation, antigens can be classified into T independent and T dependent antigens. Some antigens can directly induce the B cells to produce the Abs and are called T Independent Ans. However, some Ans require the help of T lymohocytes for the production of Abs from B cells. These Ans are called T Dependent Ans.
Mechanism of pathogenicity-Exotoxin and endotoxinaiswarya thomas
Brief description on mechanisms of pathogenicity, actions of toxins produced by various bacteria and notable endotoxins and exotoxins. Mechanism of action of some of the commonest endotoxins and exotoxins are explained.
This presentation contains 53 power point slides. These slides have description between virus and host cell interactions including concept of permissive and non-permissive infection, latent infection and host immune response to viral infection. Slides are designed for medical students, nurses, academicians who are teaching virology and microbiology in medical universities, schools or college.
Mechanism of pathogenicity-Exotoxin and endotoxinaiswarya thomas
Brief description on mechanisms of pathogenicity, actions of toxins produced by various bacteria and notable endotoxins and exotoxins. Mechanism of action of some of the commonest endotoxins and exotoxins are explained.
This presentation contains 53 power point slides. These slides have description between virus and host cell interactions including concept of permissive and non-permissive infection, latent infection and host immune response to viral infection. Slides are designed for medical students, nurses, academicians who are teaching virology and microbiology in medical universities, schools or college.
A bacteriocin discovery pipeline called BOA. Bacteriocin are ribosomal synthesize anti bacterial compounds. BOA provides leads for bacteriocin discovery
Science Shaping Our World-SHOW: Resistance is Futile: Applying Ecological and...MunevarS
March’s SHOW focused on the growing trend in microbial drug resistance. Pathogenic bacteria resistant to many or all antibiotics already exist. Coupled with the rapid decline in microbiological research at pharmaceutical companies, the rapid rate at which resistance has evolved and spread has demanded a novel approach to addressing this critical human health issue.
Anti-Microbial Activity of probiotic Lactobacilli and Optimization of Bacteri...ijsrd.com
The present study is about the anti-microbial activity of the bacteriocin producing lactobacilli and optimization of bacteriocin production. Bacteriocin was extracted by solvent extraction with chloroform and the antimicrobial activity was tested against 5 different pathogens by agar spotting method. Optimization of bacteriocin production was done for 4 different parameters such as pH, Temperature, Carbon source and Nitrogen source and the anti-microbial activity was tested against the following 5 different pathogens and the results were observed and diameter of the zone of inhibition was measured and tabulated. From the results of the study it was found that bacteriocin produced from lactobacilli has good antimicrobial activity.The present study is about the anti-microbial activity of the bacteriocin producing lactobacilli and optimization of bacteriocin production. Bacteriocin was extracted by solvent extraction with chloroform and the antimicrobial activity was tested against 5 different pathogens by agar spotting method. Optimization of bacteriocin production was done for 4 different parameters such as pH, Temperature, Carbon source and Nitrogen source and the anti-microbial activity was tested against the following 5 different pathogens and the results were observed and diameter of the zone of inhibition was measured and tabulated. From the results of the study it was found that bacteriocin produced from lactobacilli has good antimicrobial activity.
Germinating seed model; an alternative of animal models for bacterial toxins ...Bhoj Raj Singh
Pathogens of Public health importance with zoonotic potential also affect the germination and rooting in plants.
Germinating seeds of different crops are affected to varying degree and all are not equally susceptible.
Cultivars also modulate the susceptibility of seed germination to different pathogens.
Crop production may be affected in soil contaminated with sewage and night soils.
Effect of bacteria on germination of seeds also modulated by month/ season of sowing.
Introduction
Definition of an Insect Resistant Plant
What is the Bt gene?
History
The crystal ( cry)Proteins
Definition of cry protein
How does Bt work?
Mechanism of Bt toxicity
Mode of Action of Insecticidal Crystal Protein
Bt Technology
The Insect Resistance Problem
Advantages
Limitations
Conclusion
References
AIILSG
Book 1 chapter 6 part 1
This slideshare includes study of bacteria fungus virus and protozoa namely bacteriology mycology virology and protozoology
A part 2 of the same has been uploaded as well which includes study of parasites, parasitology.
Thanks and regards
Dr. Chhavi Bajaj
Ozempic: Preoperative Management of Patients on GLP-1 Receptor Agonists Saeid Safari
Preoperative Management of Patients on GLP-1 Receptor Agonists like Ozempic and Semiglutide
ASA GUIDELINE
NYSORA Guideline
2 Case Reports of Gastric Ultrasound
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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
These lecture slides, by Dr Sidra Arshad, offer a quick overview of 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 leads (limb II)
4. Differentiate between intervals and segments
5. Enlist some common indications for obtaining an ECG
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. ECG Basics, http://www.nataliescasebook.com/tag/e-c-g-basics
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
These simplified slides by Dr. Sidra Arshad present an overview of the non-respiratory functions of the respiratory tract.
Learning objectives:
1. Enlist the non-respiratory functions of the respiratory tract
2. Briefly explain how these functions are carried out
3. Discuss the significance of dead space
4. Differentiate between minute ventilation and alveolar ventilation
5. Describe the cough and sneeze reflexes
Study Resources:
1. Chapter 39, Guyton and Hall Textbook of Medical Physiology, 14th edition
2. Chapter 34, Ganong’s Review of Medical Physiology, 26th edition
3. Chapter 17, Human Physiology by Lauralee Sherwood, 9th edition
4. Non-respiratory functions of the lungs https://academic.oup.com/bjaed/article/13/3/98/278874
Pulmonary Thromboembolism - etilogy, types, medical- Surgical and nursing man...VarunMahajani
Disruption of blood supply to lung alveoli due to blockage of one or more pulmonary blood vessels is called as Pulmonary thromboembolism. In this presentation we will discuss its causes, types and its management in depth.
Report Back from SGO 2024: What’s the Latest in Cervical Cancer?bkling
Are you curious about what’s new in cervical cancer research or unsure what the findings mean? Join Dr. Emily Ko, a gynecologic oncologist at Penn Medicine, to learn about the latest updates from the Society of Gynecologic Oncology (SGO) 2024 Annual Meeting on Women’s Cancer. Dr. Ko will discuss what the research presented at the conference means for you and answer your questions about the new developments.
Triangles of Neck and Clinical Correlation by Dr. RIG.pptx
Bacterial toxin and bacteriocin
1. Santosh Yadav
BACTERIAL TOXINS AND
BACTERIOCIN
Santosh Yadav
M.Sc. Clinical Microbiology
Dept. of Microbiology
Institute of Medicine
Tribhuvan Univarsity Teaching Hospital, Nepal
1
2. Santosh Yadav
Toxins
2
Are virulence factor of most of bacteria and one of
the major cause of tissue damage.
Two types :- endotoxin and exotoxin.
3. Santosh Yadav
3
Exotoxin Endotoxin
Secreted outside cell by both
Gram positive and Gram
negative bacteria
Relesed after lysis of Gram
negative cellwall
Protein Lipopolysaccharide
Heat labile (except- enterotoxin
of S.aureus )
Heat stable ( upto 250⁰c)
Highly antigenic Less antigenic
Highly toxic in minute dose (
microgram is fatal to animals)
Moderately toxic
Filterable not so(obtained only by cell
lysis )
Can be converted to toxoid cannot
Often enzymatic action no
Properties of bacterial toxin
4. Santosh Yadav
Endotoxin
4
LPS of Gram negative cell
has three parts:- O-
antigen , core
polysaccharide and
lipid A.
Released usually when the
cell is lysed but can also be
released during vegetative
growth.
Has same chemical
composition in almost all
bacteria and has same
toxic effect ( no matter
which bacteria produce it).
Encoded by chromosomal
gene.
5. Santosh Yadav
Mode of action
5
Endotoxin
( lipid A)
Activates
macrophages
IL-1/IL-6(fever)
TNF(fever and
hypotension) i
NO
(hypotension)
Activates
complement
C3a
(hypotension ,
edema)
C5a
(neutrophil
chemotaxis)
Activates
tissue factor
Coagulation
cascade ( DIC)
6. Santosh Yadav
Exotoxin
6
Are most powerful and active in small quantities.
Either secreted by organism or leak into the
surrounding fluid after lysis of bacterial cell.
Gene for exotoxin may be present on
chromosome or plasmid or bacteriophage
DNA.
8. Santosh Yadav
A-B toxin
8
Have two components (A
and B)
B components binds to
specific cell receptor and
facilitate the internalization
of A.
Component A is active
(toxic) component.
10. Santosh Yadav
Contd…
10
Some bacteria directly
inject exotoxin into
target cell via needle
like projections called
injectosome.
Also called type III
secretory system.
Bacteria having type III
secretory system are
more virulent.
Fig:- Injectosome
12. Santosh Yadav
BACTERIOCIN
12
Produced by many bacteria, protein in nature and
have bactericidal activity.
Have killing action on strains of same or closely
related species.
First reported by Gratia in 1925, Escherichia coli
producing a substances which is active against other
strains of the same species.
Colicin – Gratia and Frederique in 1946.
Bacteriocin- Jacob and Woolman in 1953.
13. Santosh Yadav
contd…
13
Are named on the basis of their bacterial species of
origin . Some of them are
i) Colicins are bacteriocins of E.coli,
ii) Aeruginocin of P. aeruginosa,
iii) Diphthericins - C. diphtheriae
iv) Cloacin of Enterobacter cloaceae,
v) Pesticin of Y. pestis,
vi) Monocin of Listeria monocytogenes,
vii) Cerecin of Bacillus cereus
viii) Staphylococcin of Staphylococcus aureus,
ix) Warnerin of et S. warneri
14. Santosh Yadav
contd…
14
Target cells have specific receptor for
attachment of bacteriocin( same as
bacterophage)
Bacteria producing bacteriocin also carry
gene for immunity to them on chromosome or
plasmid.
Many have narrow inhibitory spectrum of
activity ( but some have activity on broad
class of bacteria)
Are plasmid or chromosomal mediated.
18. Santosh Yadav
Importance
18
Bacteriocins produced by non-pathogenic
bacteria kills other pathogenic
bacteria(Normal flora vs. Pathogens).
Bacteriocins have also been suggested for
certain cancer treatment.
Used for food presrvation in food industry (
eg..nisin produced by Lactococcus lactis is
active against many food spoiling bacteria)
Used for bacteriocin typing of clinical strains
to aid in their identification and
characterization.
19. Santosh Yadav
Bacteriocin typing
19
Done for identification of isolated strains : as they
are same or different.
A strain may be typed by:
1) Activity of their bacteriocin against a set of indicator
strains of same or closely related species, or
2) Pattern of their susceptibility to the bacteriocin of a
set of indicator strains.
If the isolates are same strains, their bacteriocin
production and susceptibility patterns will be
identical.
20. Santosh Yadav
Pyocin typing
20
Gillies and Govan(1966)- cross streaking
method
- The test strains are inoculated across the
surface of BHI agar plates.
- After overnight incubation at 37ᴼC , culture is
exposed to chloroform to kill the test strains and
then the test (producing) strains are scrapped-
off from the plate by using slide.
- The sensitive strains (Indicator strains) are
cross-streaked at right angle to the test strains.
- Incubated at 37ᴼC for 24 hours.
- Observed for inhibition of growth at each side of
the producing strain.
21. Santosh Yadav
Contd…
21
In pyocin typing technique with cross streaking
method, 105 main types and 25 subtypes can be
identified on the basis of pyocin production by
test strains using 13 indicators(1 to 8 and A to E).
Disadvantages of streak method
To remove test strains growth before application
of indicator strain.
Not reliable for mucoid colony of P. aeruginosa.
48 hour period is needed to obtain result.
22. Santosh Yadav
Bibiliography
22
Microbiology : A Human Perspective by
Anderson and Nester
Topley and Wilsons Microbiology and Microbial
infections, vol. 2
A Handbook of Clinical Microbiology ; Prof. Dr.
Bharat Mani Pokhrel
Microbiology by Tortora
Ananthanarayan and Paniker Text Book Of
Microbiology
Brock Biology of Microorganisms; Medigan and
Martinko.
Microbiology ; Lansing M. Prescott.