Last Lecture

Question 1

Who coined the term microbiology?
What are some of the prominent discoveries in microbiology (state 4)
State the four different eras in microb

Answer 1

Louis Pasteur

Prominent discoveries include:
-Microscopy
- Scientific method
- Development of medical microbiology
- Microbiology techniques

Eras:
Discovery era- when things were being found for the very first time.
Transition era-in this era, anything you say will be taken as it is
Golden era -point where you disprove certain theories
Modern era-adding to the existing knowledge we have.

Question 2

Which era did Aristotle propose the spontaneous generation theory?
What does this theory say?

Answer 2

Discovery era
Aristotle (384-322):
Aristotle proposed the spontaneous generation theory.
He stated that living organisms could develop from non living materials.
Examples:
Sudden appearance of fish in a new puddle of water
-frogs seen to appear along the muddy banks of the Nile River in Egypt
- that mice simply appeared among grain, stored in barns wth blanched rocks

Question 3

Who invented the magnifying glass in the 13TH century
Who was the first to use a lens to observe the smallest unit of tissues he called cells.

Answer 3

Roger Bacon , an english scholar, scientist and philosopher invented the magnifying glass in the 13TH century

Robert Hooke, a17th century English scientist, was the first to use a lens to observe the smallest unit of tissues he called cells.

Question 4

Who observed “animalcules”
with the use of his homemade microscopes in the discovery era

Answer 4

Soon after, the Dutch amateur biologist Antony van Leeuwenhoek observed what he called “animalcules”
with the use of his homemade microscopes.

Question 5

Which era was the theory of spontaneous generation widely accepted and which era was it disproved?
What is the theory of spontaneous generation

Answer 5

Accepted in discovery era. Aristotle brought it about.
Disproved in transition era

When microorganisms were known to exist, most scientists believed that such simple life forms could surely arise through spontaneous generation.
That is to say life was thought to spring spontaneously
from mud and lakes or anywhere with sufficient nutrients.
Thsi concept was so compelling that it persisted until late into the 19th century.

Question 6

Who first challenged the theory of spontaneous generation in the transition era ?
How did he do this?
Who proved that microorganisms were present in atmosphere.

Answer 6

Francesco Redi (1626-1697):
Francesco Redi contributed a lot in the field of microbiology.
The ancient belief in spontaneous generation was first of all challenged by Redi, an Italian physician, who carried out a series of experiments on decaying meat &its ability
to produce maggots spontaneously.
He proved that microorganisms were present in the atmosphere.

Question 7

In the transition era, apart from Francesco redi,which other scientist disproved the theory of spontaneous generation ?
How did he do this?

Answer 7

Lazzaro Spallanzani (1729-1799):
Lazzaro Spallanzani was the other scientist who by doing his experiments proved that air carries germ.
He was an Italian Naturalist who attempted to refute John Needham’s experiment.
Spallanzani disproved the doctrine of spontaneous generation.

It seems you meant to refer to Pasteur’s experiments rather than “lupus.” Here’s a comparison of the experiments conducted by Lazzaro Spallanzani and Louis Pasteur, which both aimed to disprove spontaneous generation but differed in approach:

1. Method: Spallanzani boiled nutrient broth in sealed flasks to kill existing microorganisms and observed that no microbial growth occurred as long as the flasks remained sealed.
2. Key Point: Critics argued that sealing the flasks prevented the entry of a “vital force” from the air, which they believed was necessary for spontaneous generation.
3. Conclusion: Spallanzani showed that microorganisms did not arise spontaneously; however, his experiment was not fully accepted due to the debate over the exclusion of air.

1. Method: Pasteur used swan-neck flasks containing boiled broth. The unique shape allowed air to enter the flask while trapping airborne particles in the neck, preventing them from reaching the broth.
2. Key Point: The broth remained sterile unless the flask was tilted, allowing trapped particles to contact the broth. This showed that microorganisms came from the air, not spontaneously.
3. Conclusion: Pasteur’s experiment definitively disproved spontaneous generation by proving that microbial growth resulted from airborne microorganisms, not a mysterious “vital force.”

• Air Access: Spallanzani sealed his flasks, while Pasteur allowed air to enter, addressing the “vital force” criticism.
• Flask Design: Pasteur’s swan-neck flasks specifically demonstrated that it was the microbes in the air, not the air itself, that caused contamination.
• Acceptance: Pasteur’s experiment was widely accepted and seen as conclusive, whereas Spallanzani’s faced skepticism due to the exclusion of air.

Question 8

Who else in the discovery era, which other scientist supported the theory of spontaneous generation?
How did he do this?
So last last, who brought about this theory?

Answer 8

John Needham:
• Contribution: Needham, an 18th-century British scientist, conducted experiments that seemed to support spontaneous generation. He claimed that nutrient broths, when boiled and then sealed, would develop microorganisms, suggesting that life could arise spontaneously from the broth.

For MCQs specifically asking who is credited with formulating the theory of spontaneous generation, you should pick Aristotle.

• Aristotle: He is historically recognized for introducing the concept of spontaneous generation in ancient times, suggesting that certain life forms could arise from non-living matter.
• Needham: While he provided experimental support that seemed to confirm spontaneous generation in the 18th century, his work was more about investigating and supporting the theory rather than originating it.

Thus, for the origin of the theory, Aristotle is the correct choice.

Question 9

Who finally disproved the theory of spontaneous generation in the golden era?
What theory did this person bring about instead in this golden era?

Answer 9

Spontaneous Generation is an early belief that some forms of life could arise from vital forces
present in nonliving or decomposing matter (flies from manure, etc.)
• Louis Pasteur eventually disproved spontaneous generation and proved the Theory of Biogenesis -
the idea that living things can only arise from other living things

Question 10

Who showed microbes caused fermentation and food spoilage

Answer 10

Louis Pasteur (1822-1895)

Question 11

Who are the two major contributors to the germ theory of disease
What is the germ theory

Answer 11

The Germ Theory of Disease
• Many diseases are caused by the growth of microbes ni the body and not by sins, bad character, or poverty, etc by Robert Koch.
• Two major contributors:
Louis Pasteur and Robert Koch

Question 12

Who developed pasteurization, vaccines for rabies, anthrax, chicken cholera vaccine?

Who demonstrated the germ theory ?

Answer 12

Louis Pasteur (1822-1895)

In an MCQ setting where you need to choose between Robert Koch and Louis Pasteur, Louis Pasteur is the better choice for being credited with the development of germ theory.

• Louis Pasteur: He is widely recognized for his work that established the germ theory of disease. His experiments demonstrated that microorganisms were responsible for fermentation and spoilage, and he developed pasteurization as a method to kill harmful microbes in food and beverages.
• Robert Koch: While Koch made significant contributions to germ theory, such as identifying specific pathogens responsible for diseases (Koch’s postulates), his work came after Pasteur’s foundational experiments. Koch’s contributions helped confirm and expand on Pasteur’s germ theory.

• Louis Pasteur: Primary figure in the development of germ theory.
• Robert Koch: Key contributor and confirmer of the theory.

For an MCQ asking who brought about the germ theory, Louis Pasteur is the preferred choice.

Question 13

Who found the cause of anthrax, TB, and cholera
And Developed pure culture methods,

Answer 13

Robert Koch (1843-1910)

Question 14

What are Koch’s postulates

Answer 14

Established Koch’s
postulates - a sequence of experimental steps that
verified the germ theory

Koch’s Postulates
1.organism is Isolated from sick organism
2 bacteria or bacteria is Grown in lab culture
3. Healthy organism displays disease when bacteria is inoculated into it
4 New isolated culture identical to original and grown in the lab

Question 15

Which two people each demonstrated the presence of heat resistant forms of some microbes?
Which of them determined these forms to be heat- resistant bacterial endospores?

• Sterility requires the elimination of al life forms including endospores and viruses. True or false?

Answer 15

John Tyndall and Ferdinand Cohn each demonstrated the presence of heat resistant forms of some microbes.

• Cohn determined these forms to be heat- resistant bacterial endospores.

Question 16

Who discovered endospores

Answer 16

Ferdinand Cohn

In an MCQ setting, you should pick Ferdinand Cohn for the discovery of endospores.

• Ferdinand Cohn: He is credited with discovering and describing endospores in the 19th century. His work on bacterial spores helped establish the concept of endospores as a resistant structure formed by certain bacteria to survive harsh conditions.
• John Tyndall: Although Tyndall also made significant contributions to microbiology, particularly in demonstrating the role of heat-resistant spores in contamination, he did not discover endospores. His work helped confirm and expand on Cohn’s findings.

• Ferdinand Cohn: Discovered and described endospores.
• John Tyndall: Contributed to understanding heat resistance and microbial contamination.

For the discovery of endospores, Ferdinand Cohn is the correct choice.

Question 17

What is tyndallisation
Who brought it about?

Answer 17

John Tyndall (1820 - 1893):
He discovered highly resistant bacterial structure, later known as endospore, in the infusion of hay(but he didn’t first discover endospores. Cohn did) . Prolonged boiling or intermittent heating was necessary ot kill these spores, to make the infusion completely sterilized, a process known as
Tyndallisation

Tyndallization is a method of sterilization developed by John Tyndall in the 19th century. It is designed to kill heat-resistant bacterial spores and involves a process of intermittent boiling.

1. Heating: The material is heated to 100°C (boiling point) for 30 minutes.
2. Cooling: The material is allowed to cool for 24 hours.
3. Reheating: The heating and cooling cycle is repeated for three consecutive days.

• Spore Destruction: The repeated heating kills vegetative bacterial cells and allows bacterial spores to germinate. The subsequent heating then destroys the newly germinated vegetative cells.

• Tyndallization was used historically to sterilize heat-sensitive materials that could not withstand continuous high temperatures. It is now largely replaced by more modern sterilization techniques but was an important step in the development of microbial control methods.

Question 18

Who was known for his notable contribution to the antiseptic treatment for the prevention &cure of wound infections. He is known as the father of antiseptic surgery.

Answer 18

Lord Joseph Lister (1827-1912):
Lord Joseph Lister was afamous English surgeon
si known for his notable contribution ot the antiseptic
treatment for the prevention &cure of wound infections. He is known as the father of antiseptic surgery.

Question 19

Who was the first to prevent small pox?
Who discovered penicillin and what plant did he discover it from?

Answer 19

Edward Jenner (1749-1823):
Edward Jenner was an English physician was the first to prevent small pox.
He contributed a lot in vaccination.

Alexander Fleming:
The credit for the discovery of this first wonder drug’
penicillin in 1929 goes to Sir Alexander Fleming of England.
He discovered penicillin from penicillin notatum.

Question 20

Who gave his contribution in the treatment of syphilis by arsenic.

Answer 20

Paul Ehrlich (1854-1915):
Paul Ehrlich gave his contribution in the treatment of syphilis by arsenic.

Question 21

In the development of aseptic techniques, the human body is a source of infection. Which doctors did the following;
1. observed that mothers of home births had fewer infections than those who
Gave birth in hospitals
2. corelated infections with physicians coming directly from the autopsy room to the maternity ward and is the Father of hand hygiene
3. introduced aseptic techniques to reduce microbes In medical settings and prevent wound infections
• Involved disinfection of hands using chemicals prior to surgery
• Use of heat for sterilization

Answer 21

D.r Oliver Wendell Holmes - observed that mothers of home births had fewer infections than those who
Gave birth in hospitals
- D.r Ignaz Semmelweis - corelated infections with physicians coming directly from the autopsy room to the maternity ward and is the Father of hand hygiene
- Joseph Lister - introduced aseptic techniques to reduce microbes In medical settings and prevent wound infections
• Involved disinfection of hands using chemicals prior to surgery
• Use of heat for sterilization

Question 22

Who brought about the following:
1.Diptheria antitoxin
2.role of mosquitoes in transmitting Malaria
3.causative agent of Tuberculosis and cholera
4. Pioneered study of Phagocytosis
5. Found antibiotic properties of Penicillin

Answer 22

Many nobel laureates have their huge contribution ni the field of microbiology:
Emil Von Behring -Dipth antitoxin
Ronald Ross - Malaria
Robert Koch - Tuberculosis
Ilya mechnikov-Phagocytosis Flemming - Penicillin

Question 23

What is taxonomy and who originated the formal system?
What three things is taxonomy concerned with

Answer 23

Taxonomy: organizing, classifying, and naming living things
- Formal system originated by Carl von Linné
• Concerned
with:
- Classification - orderly arrangement of organisms into groups
- Nomenclature - assigning names
- Identification - determining and recording traits of organisms for placement into taxonomic schemes

Question 24

Scientific Method
• Approach taken by scientists to explain a certain natural phenomenon
• Form a hypothesis - a tentative
explanation that can be supported or refuted
Deductive approach:”if”…”then”
• a lengthy process of experimentation,
analysis, and testing either supports or refutes the hypothesis

Results must be published and repeated by other investigators.
• if evidence of a theory is so compelling that the next level of confidence is reached, it ti becomes a Law or principle.
•if hypothesis is supported by a-growing body of evidence and survives rigorous scrutiny, it moves to the next level of confidence - it
becomes a theory.
True or false

Question 25

Two cell lines - Prokaryote - microscopic, unicelular organisms, lack nuclei and membrane-bound organelles - Eukaryote-unicelular(microscopic)andmuiticelular, nucleus and membrane-bound organelles • Viruses -Acelular, parasitic particles composed of anucleic acid and protein What are the two major groups of appendage sim bacteria What are the three parts of a flagella

Answer 25

Appendages - Two major groups of appendages: • Motility - flagella and axial filaments (periplasmic flagella) • Attachment or channels - fimbriae and pili • Glycocalyx - surface coating Flagella: Rotates 360° • Functions ni motility of cel through environment 3parts - Filament - long, thin, helical structure composed of protein flagellin - Hook - curved sheath - Basal body - stack of rings firmly anchored ni cel wal

Question 26

Flagellate responses Guide bacteria in a direction in response to external stimulus Give two example of stimulus The signal from the stimulus sets flagella into motion clockwise or counterclockwise, clockwise results in the bacteria moving what direction? Anti clockwise or counterclockwise results in bacteria moving in what’s direction? Difference between chemotaxis and diapedesis

Answer 26

Guide bacteria in a direction in response to external stimulus: Chemical stimuli - chemotaxis; positive and negative Light stimuli - phototaxis Signal sets flagella into motion clockwise or counterclockwise: Counterclockwise - results in smooth linear direction - run Clockwise - tumbles Here's a concise guide on bacterial movement in response to external stimuli and the concepts of diapedsis and chemotaxis: ### **Bacterial Movement in Response to Stimuli**: 1. **Chemotaxis**: - **Chemical Stimuli**: Bacteria move toward or away from chemical stimuli. - **Positive Chemotaxis**: Movement toward a favorable chemical attractant (e.g., nutrients). - **Negative Chemotaxis**: Movement away from a harmful or unfavorable chemical (e.g., toxins). 2. **Phototaxis**: - **Light Stimuli**: Bacteria move toward or away from light. - **Positive Phototaxis**: Movement toward light, often to benefit from photosynthesis. - **Negative Phototaxis**: Movement away from light if it is harmful or not beneficial. 3. **Flagellar Motion**: - **Counterclockwise Rotation**: Results in smooth, linear movement called a "run." Bacteria move in a straight line toward attractants. - **Clockwise Rotation**: Causes the flagella to form a bundle and leads to "tumbling." This results in random changes in direction, helping the bacterium reorient itself. In the context of bacterial movement: 1. **Counterclockwise Rotation:** - When flagella rotate counterclockwise, they bundle together, resulting in smooth, directed movement (a "run"). This helps the bacterium move in a straight line towards favorable stimuli (chemoattractants). 2. **Clockwise Rotation:** - When flagella rotate clockwise, they tend to separate, causing the bacterium to tumble or change direction randomly. This tumbling allows the bacterium to reorient and adjust its movement. ### **Response to Favorable Stimuli:** - **Initial Response:** If a bacterium is initially moving away from favorable stimuli or an attractant and detects the presence of these stimuli, it will use the tumbling behavior (resulting from clockwise rotation) to reorient itself. - **Correcting Path:** After tumbling, if the bacterium's new orientation is towards the attractant, it will switch back to counterclockwise rotation to continue moving smoothly towards the attractant. ### Summary: Clockwise rotation induces tumbling to reorient the bacterium. Once the bacterium aligns its path towards a more favorable stimulus, it will resume counterclockwise rotation to move smoothly toward the attractant. ### **Diapedesis**: - **Definition**: The process by which cells, particularly white blood cells (leukocytes), move through the endothelial lining of blood vessels to reach tissues where they are needed, such as sites of infection or injury. - **Mechanism**: - **Adhesion**: Leukocytes adhere to the endothelial cells lining the blood vessels. - **Transmigration**: The leukocytes squeeze through the gaps in the endothelial cells. - **Movement**: Once outside the blood vessels, they move toward the site of infection or inflammation in response to chemotactic signals. ### **Summary**: - **Chemotaxis** and **Phototaxis** are methods of bacterial movement in response to chemical and light stimuli, respectively. - **Diapedesis** involves leukocytes moving out of blood vessels to reach tissues in response to signals, aiding in immune response and tissue repair.

Question 27

How do periplasmic flagella cause the bacteria to move Flagella are Fine, proteinaceous, hairlike bristles emerging from the cell surface Fimbrae:Function in adhesion to other cells and surfaces Fimbrae are short and flagella are long Glycocalyx is Coating of molecules external to the cell wall, made of sugars and/or proteins Two types: .1 Slime layer - loosely organized and attached 2. Capsule - highly organized, tightly attached

Answer 27

Periplasmic flagella are Internal flagella, enclosed in the space between the outer sheath and the cell wall peptidoglycan • Produce cellular motility by contracting and imparting twisting or flexing motion

Question 28

Limitations of koch postulate Diff between decontamination and sterilization

Answer 28

You can’t grow viruses on culture media Certain bacteria cause the same symptoms example is shigella causing diarrhea and plasmodium causing diarrhea and another bacteria causing the same diarrhea Here’s a summary of the limitations of Koch's postulates: 1. **Asymptomatic carriers**-people can have the bacteria and not cause symptoms 2. **Inability to culture all pathogens**-example is treponema pallidum 3. **Disease complexity**-some diseases are caused by multiple pathogens or or by complex interactions between the pathogen and the host’s immune system, making it difficult to apply Koch’s postulates. For example, Helicobacter pylori is associated with peptic ulcers, but not everyone infected develops ulcers. 4. **Ethical considerations**-The third postulate requires that the cultured microorganism should cause disease when introduced into a healthy host. It’s unethical to intentionally infect humans with a pathogen to fulfill this criterion. Animal models are sometimes used, but they may not perfectly mimic human disease. 5. **Pathogen variability**-Some pathogens may evolve or vary in virulence, leading to different disease outcomes. This variability complicates the application of Koch’s postulates because the same pathogen might not always cause the same disease in every host. 6. **Microbiome influence**. 7. **Viral and prion diseases**. Also, antony lee vanheeke brought about microscopes Also: before you can support or disprove something, you have to form a hypothesis. So you say if this happens then this may occur. Hypothesis(if accepted)- theory(if accepted)- law or principle Decontamination: • Definition: The process of cleaning an object or surface to remove or reduce the number of microorganisms to a level that is considered safe. • Purpose: To make an item safe for handling or further treatment. It does not necessarily kill all microorganisms. • Methods: • Cleaning: Physical removal of dirt, organic matter, and microorganisms through washing and scrubbing. • Disinfection: Use of chemicals to reduce or destroy pathogenic microorganisms, but not necessarily all microbes or their spores. Common disinfectants include bleach and alcohol. Sterilization: • Definition: The process of completely eliminating all forms of microbial life, including bacteria, viruses, fungi, and spores, from a surface or object. • Purpose: To achieve a state of absolute cleanliness where no viable microorganisms remain. • Methods: • Heat Sterilization: Using high temperatures, such as in an autoclave (steam under pressure) or dry heat ovens. • Chemical Sterilization: Using chemical agents like ethylene oxide or hydrogen peroxide gas. • Radiation: Using ionizing radiation (e.g., gamma rays) or non-ionizing radiation (e.g., UV light) to kill microorganisms. • Filtration: Removing microorganisms from liquids or gases by passing them through a filter with pores small enough to trap them.

Question 29

Study of fungi is mycology Organisms that are 40micrometer above- can be seen with naked eye Below that, you can’t see with the naked eye Light microscope- bacteria, fungi, Protozoa Virus- electron microscope. They are the smallest Aristotle is one of the men that proved microorganisms exist Robert Hooke brought about discovery of cells Antony brought about single lens that magnified up to 300x First person to use Microscope to observe microorganisms. Father of microscopes. John needham - tiny organism or animalcules come from mutton gravy. He covered flasks with the gravy and heated it but still microbes appeared in the mutton broth. He didn’t cover the flasks tightly enough so air could pass through and enter Spallanzi said air carries germ. He was an Italian naturalist. He finally disproved sprontanrus generation theory. He repeated John’s test. He covered one of the soups and then he covered the other soup tightly so no air will enters Louis Pasteur eventually disproved spontaneous generation theory. Father of medical Microbiology. He repeated the broth tests but used swan neck beakers. Also used three beakers Spontaneous generation- organisms come from non living things or decomposing matter such as flies from manure **Pasteurization** is a heat treatment process used to kill harmful microorganisms, such as bacteria, viruses, and molds, in food and beverages, primarily milk, without significantly affecting the product's quality or nutritional value. It was developed by **Louis Pasteur** in the 19th century. There are two main methods of pasteurization: 1. **High-Temperature, Short-Time (HTST)**: Involves heating the product to around **72°C (161°F)** for about **15–20 seconds**, commonly used for milk and juice. 2. **Low-Temperature, Long-Time (LTLT)**: Involves heating the product to about **63°C (145°F)** for **30 minutes**, usually used for milk in smaller operations or products where higher temperatures might affect flavor or texture. Pasteurization does not sterilize food, meaning it does not kill all microorganisms, but it significantly reduces the number of pathogens, making the product safer for consumption and extending its shelf life. Koch’s postulates are the sequential experimental steps that verified the germ theory. Brought about relationship between Microorganisms and disease they are causing. So if someone has cholera, they should be able to isolate vibrio cholerae. Take note that the organism isolated is inoculated back into a healthy organism not an unhealthy one. Edward Jenner was first person to do vaccination. He was the first person to do inoculation. Purpural fever was what was increasing at the time among the maternity ward and Dr Ignaz Semmelweis realized that it was due to doctors going to autopsy room and going straight to maternity ward without washing hands. Joseph lister- heat for sterilization and using chemicals to disinfect hands PART 2 Eukaryotes can be unicellular or multicellular Prokaryotes are only unicellular and don’t have nuclei. Viruses are non living and don’t have cells. Structure: External structure- 1.Appendages; major groups are the ones for motility and for attachment. Fimbrae,pilus for attachment or channels. flagella and axial filament or periplasmic flagella for motility. (Also as appendage)glycocalyx- slime mould or slime layer and capsule. The capsule is highly organized. Made up of sugars,salts and amino acids. Used for attachment,prevent dehydration and has anti phagocytic action. Internal structures: 1.cell wall 2.inner cell membrane 3.Cytoplasm and structures in it Pili are found only in gram negative cells. Join BACTERIAL cells for partial DNA transfer Cell Theory (developed by Schwann and Schleiden): This theory states that all living organisms, both plants and animals, are composed of cells, which are the basic units of life. In summary, Matthias Schleiden is credited with identifying and stating that plants are made of cells, while Theodor Schwann is credited with the same for animals.

Answer 29

The discovery of cells by Robert Hooke in 1665 laid the foundation for further research into cell biology. However, it was Matthias Schleiden, a German botanist, who in 1838 proposed that plants are made of cells. The following year, Theodor Schwann, a German physiologist, extended this idea to animals, stating that animals are also made of cells. Together, Schleiden and Schwann formulated the cell theory, which posits that all living organisms are composed of cells.

Question 30

Eukaryotes can be unicellular or multicellular Prokaryotes are only unicellular and don’t have nuclei. Viruses are non living and don’t have cells. Structure: External structure- 1.Appendages; major groups are the ones for motility and for attachment. Fimbrae,pilus for attachment or channels. flagella and axial filament or periplasmic flagella for motility. (Also as appendage)glycocalyx- slime mould or slime layer and capsule. The capsule is highly organized. Made up of sugars,salts and amino acids. Used for attachment,prevent dehydration and has anti phagocytic action. Internal structures: 1.cell wall 2.inner cell membrane 3.Cytoplasm and structures in it Pili are found only in gram negative cells. Join BACTERIAL cells for partial DNA transfer Second class; Gram pos: Peptidoglycan Periplasmic space Inner cell membrane Gram neg: Outer cell membrane Periplasmic space: Peptidoglycan is here Inner cell membrane Teichoic and lipoteichoic in the peptidoglycan layer of the GRAM POS bacteria will MAKE your body produce immune response against the bacteria By stimulating immune response CUZ THE BODY WILL RECOGNIZE TBE TEICHOIC AND LIPOTEICHOICE Porin proteins are in the upper layer of the outer membrane Body responds to LPS IN THE GRAM NEGATIVE CUZ THE LPS WILL STIMJKAGE IMMUNE RESPONSE Mycobacterium and Nocardia don’t have typical cell wall. Theirs is similar to Gram pos just that on the surface of the Peptidoglycan, they have mycolic acid (cord factor ) layer over the peptidoglycan. Because of this mycolic acid, you can’t use gram stain to stain them. Cell membrane is site for nutrient processing and synthesis in bacteria. I thought it was the cytoplasm??? Chromosome in bacteria:single circular double stranded DNA molecule Inclusion bodies in bacteria store gases too Cytoskeleton are made up of protein polymers Short and plump rods: coccobacillus Curved rods:vibrio Cocci in a chain- strept cocci Cocci in clusters-staph ### Five Gram-Positive Bacteria: 1. Staphylococcus aureus 2. Streptococcus pyogenes 3. Bacillus anthracis 4. Listeria monocytogenes 5. Clostridium botulinum,tetani 6.Bacillus ### Five Gram-Negative Bacteria: 1. Escherichia coli 2. Neisseria meningitidis and gonorrhea 3. Pseudomonas aeruginosa 4. Proteus mirabilis 5. Helicobacter pylori Shigella 2. Vibrio cholerae 3. Salmonella 4. Actinobacter (if you meant Acinetobacter, it is Gram-negative) If you’re referring to Actinobacteria, they are a phylum that contains Gram-positive bacteria like Mycobacterium and Streptomyces. Capsids are protein coat or shell Virus particle is made up of covering and central core. The covering is made up of capsid or envelope (not everyone has) Central core: Nucleic acid, matrix proteins enzymes(not all have) Bacteria with matrix proteins enzymes are called? So las las, it’s capsid and either a DNa or RNA. This is the basic structure of the virus. Capsid is made up of small subunits of identical units of proteins called capsomeres. Combination of capsomeres forms capsid. Atypical viruses don’t have capsid but have dense layer of lipoproteins. DNA viruses are either circular or linear. You don’t need to copy the rna before it can be translated into proteins: Positive sense RNA RNA VIruses may be segmented into separate RNA pieces Matrix protein enzymes examples; - [ ] Polymerase: RNA ,DNA Convert negative sense to positive sense RNA. Are used in transcription - [ ] Replicases: copy rna - [ ] Reverse transcriptase- synthesizes dna from rna by HIV Viruses Viruses are classified based on structure, chemical somposition and genetic makeup Family Genus Poxviridae orthopoxvirus Herpresviridae simplex virus Picronavurus enterovirus New viral particles are constructed to become progeny virus at the Assembly stage. I thought it was virions??? Here’s a breakdown of the terms **prophage**, **progeny**, and **provirus**: 1. **Prophage**: This refers to the **viral DNA** of a **bacteriophage** (a virus that infects bacteria) that has been integrated into the **host bacterium's DNA**. It stays dormant in the bacterial genome and can replicate along with the bacterial DNA. Under certain conditions, the prophage can reactivate, leading to the production of new phage particles. 2. **Progeny**: In a viral context, this refers to the **newly produced viral particles** (offspring of the virus) after viral replication within a host cell. These progeny viruses or progeny virions can go on to infect other cells. 3. **Provirus**: Similar to a prophage, a provirus is the **viral DNA** that has integrated into the **DNA of a eukaryotic host cell** (e.g., in retroviruses like HIV). The provirus remains part of the host genome and can either stay dormant or become active to produce new viruses. Unlike prophages, proviruses may not always exit the host genome, but they can still produce viral particles. Each term refers to different phases or types of viral integration and replication within a host. Yes, **progeny viruses** and **virions** refer to the same concept, but they emphasize different aspects: - **Progeny viruses**: This term refers to the new viral particles produced after a virus replicates inside a host cell. It highlights the fact that these are the **offspring** of the virus after replication. - **Virions**: This term specifically refers to the **mature, fully assembled, and infectious viral particles** that are ready to infect new cells. In summary, progeny viruses become virions once they are fully formed and ready to leave the host cell to infect new cells. You're correct! The terms **"progeny virus"** and **"virions"** are often used interchangeably, but they describe different aspects of the same concept: - **Progeny virus** refers to the new virus particles that are being formed or produced within an infected cell. - **Virions** are the fully assembled, mature, and infectious virus particles that can leave the host cell and infect new cells. So, during the **Assembly** stage of viral replication, **new virions** (mature progeny virus particles) are constructed. Once these virions are complete, they can go on to infect other cells. Remember; building blocks are produced at synthesis and the building blocks are used to construct a house using assembly DNA viruses replicate in nucleus RNA replicate in cytoplasm Clumping cells to form one big giant cell: cytopathic effect of virus Viral specific cytopathic effects: 1.Small pox: cells round up (example is giant cell) and inclusions appear in cytoplasm 2.Herpes: cells fuse to form multinucleated syncytia,nucleus rinclusons 3.Adenovirus makes cells clump together and brings nuclear inclusions 4.Measles virus forms syncytia or multinucleated viruses and inclusions 4. Influenza causes cells to round up without inclusions 5.Poliovirus causes cell lysis but no inclusions 6.Rabies virus introduced Negri bodies which are cytoplasmic inclusions and they don’t change the cell shape. Negri bodies are eosinophilic, cytoplasmic inclusions found in the neurons of individuals infected with the rabies Inclusion bodies introduce protein bodies to enable virus to survive and take control of metabolic machinery of host

Answer 30

Smallpox: Shape changes (rounds up) & Cytoplasmic inclusions (giant cells). 2. Herpes: Huge cells (syncytia) & Nuclear inclusions. 3. Adenovirus: Aggregates (clump together) & Nuclear inclusions. 4. Measles: Multinucleated cells (syncytia) & Nuclear inclusions. 5. Influenza: Isolation (rounds up) without inclusions. 6. Poliovirus: Perishes (cell lysis) without inclusions. 7. Rabies: Round cells (no shape change) & Negri bodies (cytoplasmic inclusions). Here’s an alternative method using a storytelling approach that connects each virus with its cytopathic effect: ### Story: **"In a Viral Town, Each Virus Had Its Quirk"** 1. **Smallpox**: The **round** house (cells round up) had a giant living in it (giant cells). 2. **Herpes**: The **hugging** party (syncytia) led to a **crowded** living room with **nuclear** trophies (nuclear inclusions). 3. **Adenovirus**: The **clumping** friends (cells clump together) formed a **team** to win the **nuclear** game (nuclear inclusions). 4. **Measles**: At the **multinucleated** reunion, everyone joined hands (syncytia) and shared **inclusions** of memories. 5. **Influenza**: The **sad** roundabout (cells round up) had no decorations (no inclusions). 6. **Poliovirus**: The **bursting** balloons (cell lysis) were left without any party favors (no inclusions). 7. **Rabies**: The **eerie** shadows (Negri bodies) in the **quiet** house didn't change the **shape** of the room. ### Key Takeaways: - **Round house** for Smallpox - **Hugging party** for Herpes - **Clumping friends** for Adenovirus - **Multinucleated reunion** for Measles - **Sad roundabout** for Influenza - **Bursting balloons** for Poliovirus - **Eerie shadows** for Rabies ### Recap: By weaving each virus's effects into a story, you can create a vivid narrative that makes it easier to recall the specifics of each cytopathic effect.

Question 31

Parasitology; Apicomplexa divide by multiple fission not binary fission. How tapeworm survives without digestive system(has tegument which is a body surface that it uses to absorb nutrients from host gut) Nematodes don’t have sensory structures. Trypanosomes are obligate parasites and have antigenic variation as their way of evading host response. Protozoa is a sub kingdom and those sarco mastigophora and things are the phylum. Apicomplexa doesn’t have locomotion structures Example of sarcodina is amoeba or entamoeba Example of mastigophora is giardia Microspora produce motile spores. (Non-Motile Spores: Microspora produce spores that are typically non-motile. They aren’t motile wai) So only apicomplexa doesn’t have locomotion structures. Metazoa are sub kingdom. Flat worms alimentary canal have a blind ending Strongyloides are threadworms but the man said pinworms . Taenia Saginata is cow tapeworm Taenia solium is for pig tapeworm Fish tapeworm(D latum infection is the biggest tapeworm) What is the smallest tapeworm? H nana which is a cestode or tapeworm Which is common in Africa H nana and ethnococcus species are cestodes that affect Africans more Schistosoma(haematobium mansoni,etc) Strongyloides stercoralis = threadworm, not a whipworm. • Taenia saginata (beef tapeworm) and Taenia solium (pork tapeworm) are correct. • Diphyllobothrium latum = fish tapeworm, the largest tapeworm. • Hymenolepis nana = dwarf tapeworm, the smallest tapeworm. • H. nana and Echinococcus species are common cestodes in Africa. • Schistosoma haematobium (urinary) and S. mansoni (intestinal) are significant parasites in Africa. Schistosoma are trematodes. • x100 lens requires oil; x40 and x60 generally do not unless specifically labeled as oil-immersion lenses. Toxoplasma gondii affect the eye and tryoabsksoma brucei affect the CNS that’s why you’re always sleepy Look at medically important protozoan species How the infections can be controlled (for reading sake) Many hyphae are called mycelia. Most fungi are multicellular and have multicellular phases in their life cycle Draw parts of microscope Microscope uses both the objective and eyepiece lens for magnification of objects. X100,x60 and x40, you need oil. Oil makes light focus on the objective lens Dark areas and light areas are seen in TEM. Fixed mounts: Sample must stick to slide. This is ensured by drying or fixing fusing heat. The next step after fixing is to stain. Dyes to create contrast so you can see the structures of the organism Negative stains only stain positively charged organism. If the organism is negatively charged, it will be repelled and will stain the background not the organism. Primary stain stains microorganism Secondary stain or counter stain enhances the brightness of the organism or primary stain. The **acid-fast stain** involves the use of **carbol fuchsin(gives red)** as the primary stain and **methylene blue** or **brilliant green** as the counterstain. In the Gram stain, the primary stain is crystal violet, not methylene blue. Here’s the process: 1. Primary stain: Crystal violet – This stains all cells purple. 2. Mordant: Iodine – This forms a complex with crystal violet, enhancing retention in Gram-positive cells. 3. Decolorization: Alcohol or acetone – This removes the stain from Gram-negative cells, but Gram-positive cells retain the purple color. 4. Counterstain: Safranin – This stains the decolorized Gram-negative cells pink/red, while Gram-positive cells remain purple. So, methylene blue is not part of the Gram stain procedure, but crystal violet is the primary stain, and safranin is the counterstain. Methylene blue can be used as a simple stain to highlight the general structure of cells and bacteria, making it easier to observe them under a microscope. 5% carbon dioxide to culture gram negative 18-24hours at a temp of 37 degrees Celsius Streaking spaces the microbes in the sample on the media. Here’s how **streaking**, **loop dilution**, and **spread plate** techniques differ from one another: ### 1. **Streaking Method**: - **Purpose**: To isolate individual colonies from a mixed culture or sample. - **Process**: A small amount of the sample is spread (or streaked) in a pattern over the surface of the agar plate using an inoculating loop. The sample is diluted as the streak progresses. - **Outcome**: Produces individual colonies that can be isolated and identified. - **Use**: Best for isolating specific microorganisms from a mixture or ensuring a pure culture. ### 2. **Loop Dilution**: - **Purpose**: To reduce the concentration of microorganisms in a sample and grow them within the agar medium itself. - **Process**: A loop containing a small amount of the sample is transferred into a series of liquid media tubes (usually molten agar). Each successive dilution decreases the microbial concentration. The diluted samples are then poured into Petri dishes, where they solidify. - **Outcome**: Bacteria grow throughout the agar, resulting in colonies embedded in the medium. - **Use**: Useful for counting microorganisms or when you want to see the growth within the medium rather than just on the surface. ### 3. **Spread Plate Method**: - **Purpose**: To evenly distribute microorganisms over the surface of the agar plate. - **Process**: A diluted sample is pipetted onto the surface of the agar plate, and then a sterile glass or metal spreader is used to spread the sample across the plate. - **Outcome**: Results in an even layer of microbial growth, which can help determine the number of viable microorganisms (colony-forming units, CFUs) in the sample. - **Use**: Typically used for quantitative purposes, like counting the number of viable cells in a sample. ### Key Differences: - **Streaking**: Focuses on isolating single colonies through a progressive dilution across the plate. - **Loop Dilution**: Involves mixing the sample into molten agar for microbial growth both on the surface and inside the medium. - **Spread Plate**: Spreads a diluted sample evenly over the surface He didn’t do types of isolation so don’t focus so much there Inspection will show you if you’re getting a pure culture( one type of microbe growing), mixed growth (multiple microbes growing) or contaminant Anaerobic and transport media under functional (Amies and Stuart media) as a type of class of media. Most common use media: Nutrient broth Nutrient agar Enriched Media(blood agar and chocolate agar) Selective media example: Mcconkey agar prevents the growth of all gram pos bacteria and allows growth of all gram neg Differential media example; Mcconkey agar After making them grow on media,we use other methods to look at them. Example is staining or preparing mounts for them Do plenty wet mounts for parasitology Bacteriology: culturing and other staining methods Virology: cell cultures, live animal inoculation,bird embryo In the multiplication cycle of viruses, enveloped viruses are released by ?

Answer 31

Strongyloides: • Strongyloides are not whipworms. Instead, Strongyloides stercoralis is a type of threadworm, not a whipworm. It is a parasitic nematode that can cause strongyloidiasis in humans. • Whipworms belong to the species Trichuris trichiura, which causes trichuriasis. 2. Taenia saginata and Taenia solium: • Correct! • Taenia saginata is the beef tapeworm, associated with undercooked or contaminated beef. • Taenia solium is the pork tapeworm, associated with undercooked or contaminated pork. 3. Diphyllobothrium latum (Fish Tapeworm): • Correct! Diphyllobothrium latum is the largest tapeworm that can infect humans, and it is associated with eating raw or undercooked freshwater fish. 4. Smallest Tapeworm: • The smallest tapeworm known to infect humans is Hymenolepis nana (also called the dwarf tapeworm). It is only about 15-40 mm in length. 5. Tapeworms in Africa: • Hymenolepis nana and Echinococcus species are indeed cestodes (tapeworms) that can affect people in Africa, particularly in regions where hygiene conditions are poor or where there is close contact with livestock (like sheep or dogs for Echinococcus). • H. nana causes hymenolepiasis, which is often associated with fecal-oral contamination. • Echinococcus granulosus causes hydatid disease (echinococcosis), which is transmitted via contact with dogs that carry the parasite. 6. Schistosoma species: • Correct! Schistosoma haematobium, S. mansoni, and others are trematodes (flukes) that cause schistosomiasis (bilharzia). • S. haematobium affects the urinary system. • S. mansoni affects the intestinal tract. 7. Microscope Objectives (x100, x60, x40): • x100 objective is an oil immersion lens, which means it requires a drop of oil between the lens and the slide for clearer viewing at high magnification. • x40 and x60 lenses are typically dry lenses and do not require oil. However, in some microscopes, there is an option for an oil-immersion x60 objective.