The Microbial World and You

Question 1

What are microorganisms? Explain the equivalence of micrometers to millimeters

Answer 1

Microorganisms- are organisms that INDIVIDUALLY are too small to be seen with the unaided eye (< 200 um)
1 um= 1/1000 mm (millimeter)

Question 2

Define Microbiology and discuss an example of a microorganism that causes disease

Answer 2

Microbiology- is the study of Microorganisms
-GERMS are microorganisms that can cause disease

Question 3

What is another term for microbes that cause disease?

Answer 3

PATHOGENS

Question 4

discuss how microbes affect our lives in terms of human health and environment

Answer 4

Microbes in our lives
Human Health:
-A few are PATHOGENIC (disease-causing) (less than 1%)
-many are beneficial:
-prevent bacterial pathogen colonization (competing for space and nutrients, affect conditions like pH and O2) produce bacteriocins (small peptides by bacteria that kill other bacteria)
-Intestinal microbes ferment food you can’t digest and produce some of the B and K vitamins

Environment:
-Help maintain the balance between living organisms and chemicals
-Fix CO2 and N2, and form the basis of food chain (Bacteria converts CO2 to carbohydrates and convert N2 to ammonia)
-Break down organic waste

Question 5

what percent of microbes are pathogens?

Answer 5

Less than 1% of microbes are pathogens (that cause disease)

Question 6

Describe the kind of commercial products that are made using microbes

Answer 6

Commercial applications:
either natural or engineered microbes are used to synthesize
*Chemical products:
(vitamins, enzymes, organic acids and alcohols)
*Therapeutic products;
-Antibiotics
-Human Insulin
*Enzyme products :
-Cellulase - break down cellulose
-proteases- degrade proteins to peptides

Question 7

Discuss the food products that can be made by microbes, including the specific microbe that makes it.

Answer 7

Food products:
-beer, wine (YEAST makes it)
-green olives, pickles, sauerkraut, cheese, yogurt (LACTIC ACID bacteria makes it)
Lactic acid bacteria- ferments sugar as byproduct and produces lactic acid
-Vinegar (LACTIC ACID bacteria- convert ethanol into lactic acid)
-Soy sauce (ASPERGILLUS species and bacteria)
-Bread (YEAST makes it)

Question 8

Define the vocabulary words used to describe microbial communities such as Microbiota/microbiome/microflora, human microbiota, normal microbiota,, and normal human microbiota

Answer 8

*Microbiota/microbiome/Microflora: the full ARRAY of microscopic organisms of a particular environment

Human microbiota/microbiome/microflor- the full array of microbes that live on and within the human body.

Normal Microbiota/microbiome/microflor or Commensal bacterial- microbes that colonize a host WITHOUT normally causing disease

Normal Human microbiota/microbiome- or Human COMMENSAL BACTERIA: Microbes that colonize the human body without normally causing disease

Question 9

Define transient microbiota/microbiome/microflora and transient Human microbiota

Answer 9

Transient microbiota/microbiome/microflora: The microorganisms present on host for a SHORT time WITHOUT causing disease
Transient Human microbiota/microbiome/microflora: the microorganisms present on or within the human body for a short time without causing disease

Question 10

Why are some microbes transient?

Answer 10

why are some microbes transient:
1. Unable to compete with residents
2. Eliminated by body’s immune system
3. Physical or chemical properties that discourage their growth (ex temperature, pH, etc)

-however those who are immunocompromised, won’t have transient microbes as they will be ones that cause disease

Question 11

Which outnumbers the other in the human body and by how much? Human cells or microbes?
what is unique about microbe images that are colored?

Answer 11

MICROBES outnumber Human cells in the body (up to 10 to 1)
-10x more microbes than human cells
Colored images of microbes are FALSE Colored. As normally bacterial do not have color

Question 12

when can our normal microbiota cause disease ?

Answer 12

Our normal microbiota can cause disease:
1. when they ESCAPE their normal habitat
ex; E. coli normally found in intestines can cause urinary tract infections in the bladder
2. IMMUNOSUPPRESION can allow otherwise harmless bacteria to cause disease
3. OVERGROWTH
-taking antibiotics can kill bacteria in body, kill gut flora and candida will grow

Question 13

Discuss the history of naming and classifying microorganism, includinfg the scientist who discovered it.

Answer 13

1735- Carolus (carl) Linnaeus (Swedish botanist and zoologist ) established the system of Scientific Nomenclature for Organisms
-provided each organism with two names: the GENUS and SPECIES

Question 14

Discuss the rules made for giving microorganisms scientific names (nomenclature)

Answer 14

Scientific Names (Nomenclature)
-Italicized or underlined
-The first letter of the genus is Capitalized and the specific epithet is lowercase
-most are constructed from Latin or Greek roots (Appendix D)
-May be descriptive (of the organism or its habitat) or Honor a scientist
-Names are used worldwide

Question 15

Discuss the nomenclature and meaning behind two examples of microorganisms like Escherichia coli and Staphylococcus aureus

Answer 15

Escherichia coli (1st word: genus; 2nd word- species)
- Escherichia Honors the discoverer, Theodor Escherich
-coli describes the bacterium’s habitat- the large intestine, or colon

Staphylococcus aureus
-1st word describes the clustered (staphylo-) Spherical (cocci) cells
-2nd word describes the gold colored (aureus) colonies

Question 16

what is the abbreviation for Staphylococcus aureus and Escherichia coli ?

Answer 16

Staphylococcus aureus: S.a
Escherichia coli: E.c

Question 17

List the different types of microorganisms

Answer 17

Types of microorganisms:
-Bacteria
-Archaea
-Fungi
-Protozoa
-Algae
-viruses

-multicellular animal parasites (NOT really microbes, but have microscopic stages in life cycled)

Question 18

Describe the characteristics of bacteria and include an example of a species

Answer 18

Bacteria
-prokaryotes
-Unicellular
-Binary fission (generally)- process of cell getting larger and splitting in Half
-Reproduce ASEXUALLY
-Cell walls composed Peptidoglycan (polymer of sugars; N-acetyl glucose amine; N-acetyl-muramic acid (linked)
-Gain energy from ORGANIC chemicals (most), INORGANIC chemicals, or Photosynthesis
ex: Haemophilus influenza
-

Question 19

What are the characteristics of Archaea?

Answer 19

Archaea
-Prokaryotes
-Unicellular
-Binary fission (generally)
-Reproduce Asexually
-Cell walls lack peptidoglycan
-Not known to cause disease
-Gain energy from organic and inorganic chemicals, but NOT photosynthesis
-Many are extremophiles
-extreme halophiles- (tolerate high salt)
-extreme thermophiles (tolerate heat)
-Methanogens- anaerobic bacteria that oxidize H and produce CO2 and methane (produce methane as a byproduct In hypoxic conditions (no O2)
ex: Halorcula species

Question 20

Discuss the characteristics of Fungi and the different types of fungi.

Answer 20

Fungi
-EUKARYOTES
-can Reproduce sexually or asexually
-Limited to Organic chemicals for energy
-Cell walls contain CHITIN
chitin- long polymer of N-acetylglucoseamine; (also gives strength to exoskeleton of crustaceas and insects)
Fungi include:
1. Molds and mushrooms: MULTICELLULAR, consisting of branching and intertwining filaments (hyphae) that collectively form mycelia
2. Yeasts are UNICELLULAR
*most fungi are MOLDS. 1% are yeasts

Question 21

Discuss the characteristics of Protozoa and include an example

Answer 21

Protozoa
-Diverse group of EUKARYOTES
-Unicellular
-Reproduce asexually or sexually
-Absorb or Surround and ingest Organic chemicals (some are photosynthetic)
-Many are MOTILE using pseudopods, cilia, or flagella
ex: Amoeba (a genus of protozoa)

Question 22

What are the characteristics of Algae?

Answer 22

Algae
-EUKARYOTES
-CELLULOSE cell walls (cellulose- long polymer of glucose)
-Unicelluar and multicellular
-PHOTOSYNTHESIS for energy
-Sexual reproduction and asexual reproduction
ex: Volvox colony 350-500 um; (500-50,000 cells old periphery) Daughter cells within a mother cell

Question 23

Discuss the characteristics of Viruses

Answer 23

Viruses
-ACELLULAR (No cells)
-consist of DNA or RNA core surrounded by a protein coat
-Coat may be enclosed in a lipid bilayer (envelope)
-Viruses are replicated only when they are living in a host cell
-inert when outside a living host
-most only seen with an electron microscope (small size; need increased resolution to see)
-ex: several HIV’s budding from a T cell

Question 24

Discuss the brief history of microbiology that was observed through many scientists. Be sure to include who discovered compound microscope and other discoveries after.

Answer 24

The First Observations
1595: Zacharias Jansen and Hans Lipperhey (same town in Holland) are credited with inventing COMPOUND microscope (3x-9x magnification) . This microscope had 2 lenses (1st enlarged and second lens- appeal images)
1665- Robert Hooke used a stronger primitive compound microscope to see INDIVIDUAL cells (30 x magnification)

Question 25

Discuss the other scienific observations that Robert Hooke had, including Cell theory.

Answer 25

Robert Hooke reported that living things were composed of little boxes, or cells, that in later years led to Cell Theory
Cell Theory- that all living things are comprise of cells (Schwann’s theory)
-He also had his observations detailed in Micrographia, the first scientific best seller that contained illustrations drawn by Hooke himself (Drew fleas and gnats)
-He was able to observe and see tiny honeycomb like structures of a cork which he referred to as cells (named after small rooms in monasteries) the cell structure of a cork (described as boxers) and drew fleas, gnats in his works.

Question 26

Explain why Robert Hooke was not able to see microbes with his microscope

Answer 26

Although Hooke’s microscope showed LARGE cells, he lacked the resolution to see microbes clearly
-the diameter of a Cork cell that he could see is 25 um (micrometers)
-Hooke could not see bacteria that was 1 um

Question 27

Who was the scientist known as “the father of microbiology “? Also discuss what they discovered and his importance in science world

Answer 27

Scientist Anton Van Leewenhoek known as “The father of Microbiology”
-from 1673-1723, Leewenhoek described live microorganisms in series of letters to the Royal Society of London
he was a dutch merchant and amateur scientist
-

Question 28

Compare and contrast the magnification of the compound microscope from Hooke and Leewenhoek

Answer 28

Hooke’s COMPOUND microscope increased magnification from 9x to 30x while van Leeuwenhoek’s SIMPLE microscope magnified around 300 x

Question 29

Why did Van Leeuwenhoek’s microscope have a Higher magnification that Hooke?
What was Leeuwenhoek able to observe with his microscope ?

Answer 29

Because his lens was much better
Leeuwenhoek saws protozoa, fungi and bacteria. He also made drawings of bacteria in 1683

Question 30

Discuss the origin of these tiny organism (microbes), including the theory of Spontaneous generation. What was the recipe for mice?

Answer 30

Prior to the 1850s, many scientists and philosophers believed in Spontaneous Generation
Spontaneous Generation: the hypothesis that living organisms could arise from nonliving matter; a vital force forms life
They tried to prove it by observing maggots from decaying corpses and flies from manure
-They found recipe for mice:
Dry shirt + Wheat + 21 days = mice

Question 31

Discuss the details of the experiment used to test spontaneous generation. Why was this experiment criticized?

Answer 31

experiment to test the spontaneous generation maggots:
-1668: Francesco Redi filled jars with decaying meat (before van Leeuwenhoek)
- wanted to pose question: Did maggots come from spontaneous generation or fly reproduction
Results:
No maggots appeared when flies prevented from laying their eggs
-They had two jars and closed one jar with meat inside it, and no maggots were there
-another jar was open with meat and maggots appeared to fly around
- This experiment was criticized because you need AIR to test for spontaneous generation and closing the jar with meat in side prevented that

Question 32

What was another idea that became a part of the experiment for spontaneous generation besides closing jar? What were they able to conclude after experiment?

Answer 32

3 trials:
1. Flask sealed with meat inside jar: No maggots
2. Flask open with meat inside jar: maggots appear
New IDEA* 3. Flask covered with GAUZE- saw no maggots, but flies were around; however flies were too complicated for spontaneous generation. Microbes could possibly undergo spontaneous generation.
Conclusion: If large forms of life didn’t arise form non life perhaps , MICROBES simple enough to be generating from Nonliving materials

Question 33

Discuss the experiments that were designed For and Against spontaneous generation of microbes, and explain how each experiment was flawed

Answer 33

Experiment FOR spontaneous generation:
-in 1745, took a flask with broth and heated it up to boil, then opened the flask, let it sit and cool for some time and led to Microbial Growth
Flaws:
1. when they cooled the flask, they OPENED the jar; things can float from the air into flask
2. Boiling does NOT kill endospores (bacteria producing endospores are resistant to boiling)

Experiment AGAINST Spontaneous
-in 1765, took a flask filled with broth an heat up to let boil, then SEALED the flask with a cap, and let sit and cool for some time; which led to NO GROWTH of microbes (hypthesize no spontaneous generation)
Flaws:
1. The jar was blocked, so no air was available for microbes .

Question 34

Discuss the relevance of the Biogenesis hypothesis in relation to spontaneous generation . What was the flaw with the Biogenesis hypothesis?

Answer 34

in 1858, the Biogenesis hypothesis further challenged the concept of Spontaneous Generation
-Biogenesis hypothesis- stated that living organisms arise from preexisting life
However, there was NO PROOF offered

Question 35

what was the experiment that finally disproved the Theory of Spontaneous Generation? Who discovered it ?

Answer 35

Louis’s Pasteur’s experiment disproved spontaneous generation
In1861: Louis PASTEUR designed a flask to let air in but seep out microbes
-Pasteur has a special flask that had a swan neck so air could get in and microbes won’t be able to reach inside flask.

Question 36

1) What could cause growth in Pasteur’s experiment?
2) How would you address the concern that the absence of growth was because boiling destroyed an essential growth factor ?

Answer 36

1) If you let one end of flask be exposed to air, so dust particles could get in, while the other end of swan neck is not exposed.
2) COME BACK!!

Question 37

What did Pasteur discover about beer and wine and spoilage?

Answer 37

Several French asked Pasteur to determine why beer and wine sour and spoil
-Pastuer discovered that when making beer and wine, YEAST (Not air) converted the sugars to alcohol by a process called FERMENTATION
- Also discovered that beer and wine spoiled when different organisms (bacteria), lin the presence of air converted the alcohol to Acetic Acid (Vinegar)
ex: acetic acid bacteria

Question 38

What was the Spoilage solution that Pasteur came up with? How does it work?

Answer 38

Spoilage solution: PASTEURIZATION (1864)
-Pasteur demonstrated that Most of these spoilage bacteria could be killed by heating below the evaporation point of the alcohol in wine/beer
Pasteurization - the application of a high heat for a short time
-two primary methods (63 degrees C/ 30 mins, 73 degrees C /16 sec)

Question 39

Discuss the purpose of pasteurization?

Answer 39

Pasteurization aims to DESTROY pathogens and Reduce the number of spoilage bacteria

Question 40

1) Is pasteurization or boiling more effective a killing bacteria in liquids ?
2) why not boil instead?

Answer 40

PASTEURIZATION is more effective at killing bacteria in liquids, because at a higher temperature (Boiling) you will kill more bacteria, but it will ruin the taste of food. COME BACK to this
2) If you boil, you will boil off the alcohol, which will alter the properties of foods. You tend to lose quality or taste of foods.

Question 41

What was Pasteur’s conclusion after experiments and spoilage solution?

Answer 41

Pasteur believed that “establishing a connection between food spoilage and microbes was a major step toward establishing the relationship between disease and microbes
-bacteria may cause diseases in human

Question 42

What is the Germ Theory of Disease

Answer 42

Germ Theory of Disease: proposed that certain microorganisms cause disease

Question 43

Discuss the observations that led to the Germ Theory of Disease, including the scientists involved.
Which scientist had the first conclusive proof of the theory?

Answer 43

Observations that led to Germ Theory Diseased:
-1835 and 1865: it was shown that silkworm diseases could be caused by a fungus and protozoan respectively
-1840s: Hungarian physician Ignaz Semmelweis showed that fever death rates following childbirth could be dropped from 20% to less than 1% by hand disinfection from one OB patient to another (ideas largely REJECTED)
1860s: English surgeon Joseph Lister was a pioneer of antiseptic surgery (5% phenol; used to wash down surface ) to prevent wound infections
-Conclusive proof of theory first came from ROBERT KOCH in 1876

Question 44

Who is Robert Koch? What are Koch’s postulates?

Answer 44

1876: A German physician, Robert Kotch, proved that a bacterium causes anthrax and provided Koch’s postulates.
Koch’s postulates were experimental steps used to prove that a specific microbe causes a specific disease
(anthrax found in cattle; bacterial illness from spore bacterium)
bacillus anthracs

Question 45

List the Koch’s postulates

Answer 45

Koch’s Postulates
Demonstrating the pathogenicity of a microorganism
1. Microorganism must be observed in every case of the disease
2. It must be isolated and grown in pure culture
3. The pure culture, when inoculated in animals, must reproduce the disease
4. Microorganism must be recovered from the diseased animal .

Question 46

1) Who came up with the word Vaccination?
2) How and when was the small pox vaccine developed? How did the vaccine work?

Answer 46

1796: Edward JENNER inoculated (injected) a person with cowpox virus, who was then protected from small pox
2) -Discovery: Jenner noticed that milk maids who had gotten cowpox virus, were also protected from small pox. Hence he used that as a way to protect people from getting small pox, by injecting others with cowpox.
Vaccination is derived from Vacca for cow
The protection is called IMMUNITY
-This occurred 70 years BEFORE Kotch established the a specific organism causes anthrax
3) Jenner’s vaccine: Jenner took material from cowpox sore on milkmaid’s (had cowpox) hand and inoculated it into 8 year old boy James Phipps’ s arm. James soon recovered from that and then Jenner inoculated James with some of small pox virus and saw no small pox disease developed in James; hence vaccine a success

Question 47

List the different types of vaccines

Answer 47

Types of Vaccines include:
-Related avirulent strains
-Live attenuated strains (same virus that causes disease, but almost devoid of pathogenicity, not really infectious )
-Heat or chemical killed virulent strains
-Isolated proteins components of virulent strains
-Nucleic acids (DNA or RNA) expressing protein components of virulent strains

Question 48

What was the First Golden Age of Microbiology? When did it occur and why was it so significant?

Answer 48

The First Golden Age of Microbiology:
-1857-1914 (approx 60 years)
-Begins with Pasteur’s work on fermentation, period of RAPID ADVANCES in the science of microbiology occurred (Pasteurization, antibiotics, germ theory, vaccination)
-This propelled Microbiology into becoming one of the main branches of biology and medicine

Question 49

What are the branches of microbiology?

Answer 49

The First Golden Age led to new branches of Microbiology:
-Bacteriology- is the study of bacteria
-Mycology- is the study of Fungi
-Virology - is the study of Viruses
-Parasitology- is the study of protozoa and Parasitic worms
-Immunology- is the study of immunity

Question 50

What is the study of archaea called?

Answer 50

BACTERIOLOGY (bacteria and archaea)

Question 51

compare and contrast the purpose of the first and second Golden Age of Microbiology, including time period

Answer 51

First Golden Age of Microbiology (from 1857-1930s)
-“The Science of Microbiology rapidly advances and a relationship between microorganism and disease Is established”

Second Golden Age of Microbiology (from 1940s- 1980s)
- “ A search or substances that could destroy pathogens without harming human cells and the birth of molecular genetics”

Question 52

Who developed the Birth of Modern Chemotherapy and what did it entail?
What are synthetic drugs? What are antibiotics?

Answer 52

The Birth of Modern Chemotherapy
-Once a relationship between microbes and disease was established, microbiologists searched for substances that killed pathogen without harming host
-CHEMOTHERAPY- Treatment of infectious disease using chemicals
-By Paul Ehrlich/ antimicrobial chemotherapy

1) Synthetic drugs- are agents produced from chemicals in the lab
2) Antibiotics- MULTIPLE Definitions
a) Strict definition: agents produced NATURALLY by bacteria and fungi and act against other bacteria
b) Broad definition: agents used to treat MICROBIAL infections

Question 53

What are semi-synthetic drugs? What are the other terms used to describe synthetic drugs or antibiotics?

REVIEW

Answer 53

Semi-synthetic drugs- take naturally occurring antibiotic or drug and modify it (through chemical reactions)
ex: ampicillin- semi-synthetic drug
-Other terms:
antimicrobial, antibacterial, antifungals, antivrials

Question 54

What was the first Drug in Europe’s Medical Aresnal and how was it made? What kind of drug was it and what was it used for?
what other solution is this drug found?

Answer 54

QUININE- first drug in Europe’s medical arsenal
-Quinine occurs naturally in Cinchona tree bark and was the First effective treatment for (17th century) for Malaria caused by Plasmodium falciparum
-it is an antimicrobial (broad definition) and a Natural drug
-SELTZER (tonic) also has quinine that can be put into soft drinks

Question 55

Discuss how the First synthetic Drugs were developed, including dates, scientist and its significance

Answer 55

The First Synthetic Drugs:
-Paul Ehrlich, German physician coined the term “magic Bullet”- a drug that could destroy a pathogen without harming the host
-Observed that some dyes stained bacterial but NOT animal cells and thought it might be possible to develop toxic dyes that would bind and kill bacterial cells without harming animal cells
-1910: developed a synthetic arsenic drug, SALVARSAN (Ehrlich 606), to treat syphilis

1930s: the burgeoning dye industry in his country prompted a German microbiologist to search for dyes for antimicrobials
-in 1932, a dye with remarkable effects on stopping some bacterial infections in mice were found . It wad found that SULFANILAMIDE, and NOT the dye itself, killed bacteria. This class of drugs were called Sulfonides or “Sulfa Drugs”

Sulfonide functional group (R1-S=0 =0-N-R3-R2)

Question 56

Discuss how microbes can be beneficial to humans and and include the people who discovered microbial ecology and what it entails.

Answer 56

The vast MAJORITY of bacteria are HARMLESS to humans and a large number are actually beneficial
-Early microbiologists focused on pathogenic microbes
-in the 1880s, Martinus Beijernick and Sergei Windogradsky were two of the first scientists that attempted to understand microbes outside of the medical context; their studies led to the field of microbial ecology
*Microbial ecology: the relationship of microorganisms with their environment, each other and plant and animal species

Question 57

What was the fortunate accident in Microbiology that occurred, and who discovered it? What problems are associated with microbial drugs?

Answer 57

Fortunate accident- ANTIBIOTICS
-1928: Alexander FLEMING accidently discovered the first antibiotic
it occurred after Fleming went on vacation and came back to observe petri dish; noticed that it had mold and staph bacteria. However, he noticed that the mold inhibited growth of bacteria
-Fleming observed that a Penicillium fungus made an antibiotic, called penicillin that killed bacteria
1940s: Penicillin was tested clinically and mass produced
Problems associated with antimicrobial drugs: RESISTANCE

Question 58

What are the more recent fields of Biology, and their importance ?

Answer 58

More Recent Fields of Biology;
1) Microbial genetics: the study of how Microbes inherit traits
2) Molecular Biology- the branch of biology that deals with Structure and function of the macromolecules (ex: proteins and nucleic acids) essential to life
-**this overlaps with other areas of biology and chemistry, particularly genetics and biochemistry
3) Genomics: The study of an organisms genes; has provided new tools for classifying microorganisms
-(used DNA sequence to compare sequencers of other bacteria, see how closely related to each other )

Question 59

why are unicellular microorganisms (bacteria/yeast) advantageous for genetic and biomedical research?

Answer 59

prior to 1940s, genetic research was based on plants on animals
-Unicellular microorganism (Bacteria/yeast) are advantageous for genetic and biochemical research:
-Less complex than animals and plants
-Life cycles of most bacteria require less than an hour, allowing the cultivation of large numbers of cells in short period of time (faster cycle)
-Well defined genetic systems can easily modify genes that facilitate studies
-Haploid genome (1 set of chromosomes) allows mutant analysis to be easy (only have to knock out one copy of gene to see phenotype of mutation)

Question 60

What is the Third golden age of Microbiology?
Why is our current time period considered the “Golden age of Classification” for these disciplines ?

Answer 60

Third Golden age of Microbiology (now):
-“advances in genomics and biotechnology help us identify genes and their function

Question 61

Why is our current time period considered the “Golden age of Classification” for these disciplines ?
REVIEW

Answer 61

-Current time period considered the Golden age of classification because we use DNA/gene sequencing to compare, and it allows us to know how bacteria is related.

Question 62

Discuss the first organized team effort to optimize biological activity of a compound through chemical modification

Answer 62

First organized team to optimize the biological activity of a lead compound through systemic chemical modification:
A toxic organic compound was chosen as a precursor chemical. Hundreds of related organoarsenic compounds were synthesized, Each was tested for toxicity, and biological activity in rabbits, infected with the syphilis-causing bacteria (Treponema palladium), Salvarsan was the best candidate. SELECTIVE TOXICITY was far from absolute -still toxic and ocassionally killed patients
-salvarsan- worked for many patients with syphilis, and did not kill some patients

Question 63

What are the main types of beneficial environmental activities?

Answer 63

Beneficial environmental activities of microbes:
1. Recycling vital elements
2. Bioremediation
3.Insect pest control
4. Biotechnology

Question 64

Explain how microbes are involved in recycling vital elements. what kind of bacteria are producers and decomposers? What are their functions?

Answer 64

Recycling Vital elements:
-C, N, O, S, P are abundant but not necessarily in useful forms. *Microorganism are primarily responsible for converting these elements to forms useful for plants and animals
Producers:
*ALGAE, Cyanobacteria, and higher plants use CO2 to p produce carbohydrates for animals, fungi, and bacteria (for energy)
-N2 is abundant but not in a form usable by plants and animals
-ONLY BACTERIA can naturally “fix” atmospheric nitrogen

Decomposers:
Microorganisms, primarily* bacteria and fungi*, play a key role in returning CO2 to the atmosphere

Question 65

Discuss the process of Bioremediation and how microbes are involved . What kind of Bacteria are involved?

Answer 65

Bioremediation
-Any process that uses organisms or their enzymes to clean up pollutants and toxic wastes
-Bacteria decompose organic material in sewage treatment plants to recycle water
-Bacteria DEGRADE or DETOXIFY pollutants such as oil, chemicals and heavy metals
Bacterial enzymes (instead of chemicals) added to drain cleaners and detergents
-Indigenous or genetically modified bacteria

Question 66

How are microbes useful for insect pest control? What are their roles? What is a Bt trangenic plants and what is its role in insect pest control?
REVIEW

Answer 66

Insect pest control:
-Insect pathogens are Alternatives to chemical pesticides
-B. thuringiensis produces a CRYSTAL protein during sporulation toxic to the digestive system of many insects, but harmless to plants and animals
-Incorporated into dusting powder or spray and requires ingestion
-targets several insect Orders, types specific to an insect family
-Bt (Bacillus Thuringiensis) transgenic plants have been available since late 1990s
-Bt transgenic plants- take a gene (DNA) from bacteria (Bacillus.t) , put it into another plant so it will form a spore and toxic crystal that will keep pests or insects away from crops

Question 67

What is Biotechnology and how are microbes involved?

Answer 67

Biotechnology: the industrial application of microbes, cells or cell components to make a useful products

-Although, the use of microbes to produce foods and chemicals is centuries old, techniques have become much more sophisticated in past few decades
ex: use of microbes in making cheese
-Milk has formed curd and has been inoculated with ripening bacteria for flavor and acidity
-The curd ish then chopped into cubes, for draining of whey and will be milled and compressed to form cheese.

Question 68

What are Biofilms? What are their characteristics?
Explain the role of EPS (extracellular matrix of polymeric substances

Answer 68

Biofilms- a complex aggregation of microorganism growing on a solid surface
ex: rocks, pipes, teeth, and medical implants
-Characterized by structural heterogeneity, genetic diversity, complex community interactions, and an Extracellular matrix of polymeric substances (EPS)
EPS- Extracellular matrix of polymeric substances aid cohesion of microorganism and adhesion of biofilms to surfaces and aid with interactions between microorganisms
ex: biofilm seen on catcher or contact lens case

Question 69

Discuss the benefits and harmful effects of Biofilms.

Answer 69

Benefits of Biofilms:
-Protect your mucus membrane from harmful microbes
-food for aquatic animals in lakes
-Can be harnessed for constructive purpose (ex: sewage treatment)

Harmful Effects of Biofilms:
-Can clog water pipes
-can colonize medical implants and cause infections
-Bacteria in biofilms have increased antibiotic resistance
-Dental plaque can lead to tooth decay

Question 70

What is an Infectious Disease?

Answer 70

Infectious Disease: a disease that occurs when a pathogen overcomes the host’s resistance

Question 71

Define the term Emerging Infectious Diseases (EIDs)

Answer 71

Emerging Infectious Diseases (EIDs): New diseases and diseases increasing in incidence

Question 72

What are the different factors that contribute to EIDS (emerging infectious diseases) ?

Answer 72

Factors contributing to EIDs (Emerging Infectious Diseases):
1. Evolutionary changes in existing organisms
-Increased pathogenicity (ex: Escherichia coli O157:H7)
O: sugar exposed outside of cell; H: protein in flagella
-change in pathogen’s ecology (Powassan virus becoming establisher in the same deer ticks that cause Lyme disease; vectors)
2. Changes in weather patterns (rain, drought)
3. Ecological disster (lot of flooding, water contaminated)
4. Innapropriate use of antibiotics (increase resistance )
5.Close interactions with wild animals, livestock (infection)
6. Spread of known diseases to new geographic regions by modern transportation (ex; West Nile virus)
7. Urbanization, expanding human settlement
8. War, Poverty
9. Animal habitat change
10. Ineffective or mistaken public health measures
11. Technological advances (ex: Legionella Pneumonia dispersed in mist from hot tubs, showers, air-conditioning systems)
12. Cultural changes (Toxic-Shock Syndrome: introduction of high absorbency tampons caused overgrowth of S. aureus and release of toxins from overgrowth; measles)
13. Use of microbes as weapons (ex: dispersal of Bacillus anthraces spores)

Question 73

Discuss the incidence of Influenza A. virus (bird flu) and its characteristics.

Answer 73

Avian Influenza A (bird flu)
-Influenza A virus (H5N1)
-Primarly in waterfowl and poultry (epizootic-killed tens of millions of birds since 2003 in Asia, Europe and Africa)
-Person to person transmission has been very RARE, limited and unsustained

2022 cases: Poultry 43,851,907/ human 1

Question 74

Discuss the incidence of Swine flu, including its characteristics and symptoms

Answer 74

Swine Flu
-in 2009, a new subtype of (H1N1) resulting from the reassortment of human and swine influenza viruses appeared
-in 2009, Swine flu was the MOST COMMON cause of flu in humans; declared a pandemic and caused 17,000 deaths
(Covid-19, 6.5 Million Deaths)
-Still circulates in humans as seasonal flu virus
-

H1N1 (Swine flu) is a type A influenza virus that affects pigs (swine)
-it can pass to humans through contact or contamination
Human swine flu symptoms include fever, nausea, sore throat
Swine flu outbreak in India, (2014-2015) resulted in 2,335 deaths

Question 75

Discuss the different subtypes that influenza A viruses are divided into, and distinguish between the two subtypes

Answer 75

Influenza viruses are divided into subtypes based on two proteins on the surface of the virus: Hemagglutinin (H) and Neuraminidase (N)
(H) enables the virus to BINDcells of the upper respiratory tract containing the sugar sialic acid on their membranes. It also allows FUSION of the viral envelope with the endoscome membrane
- (N) CLEAVES sialic acid side groups and is essential for RELEASE of progeny virus particles from the surface of an infected cell

Question 76

Discuss the bacteria Staphylococcus aureus. what kind of bacteria is it?

Answer 76

Staphylococcus aureus- ANTIBIOTIC-RESISTANT Infection
-The bacteria are generally harmless, unless they enter the body through a cut or other wound, and even then they usually cause only minor skin problems in healthy people
-However, it can be an OPPORTUNISTIC pathogen causing a wide range of infections (pimples. boils, pneumonia, food poisoning, surgical wound infection) and is a significant cause of hospital-associated infections

Question 77

What are the different kind of Antibiotic Resistant Infections?

Answer 77

Antibiotic-Resistant infections
-Stapholococcous aureus
-1950s: Penicillin resistance developed
1980s: Methicillin resistance (Methicillin- semi-synthetic drug; modified version of penicillin)
-MRSA: Methicillin-resistant S. aureus
-1990s: MRSA resistance to vancomycin reported
-VISA: Vancomycin- intermediate-resistant S. aureus
-VRSA; Vancomycin- resistant S. aureus (2002)
Vancomycin (peptide antibiotic)

Question 78

What is the difference between HA-MRSA (Healthcare-associated) and CA-MRSA (Community-associated)

Answer 78

Healthcare-associated MRSA infections are the MOST COMMON and occurs in people who have been in hospitals or other health care settings, such as nursing homes and dialysis centers

Community-associated MRSA occurs in WIDER Communtiy- among healthy people. At risk populations include groups such as high school wrestlers, child care workers, and people who live in crowded conditions

Multiple S. aureus strains have been isolated from HA-MRSA and CA-MRSA infected patients. Some are HA- or CA-MRSA specific while others have been isolated from both patients.

Question 79

What is multidrug-resistant tuberculosis (MDR-TB) ?

Answer 79

Multidrug-resistant Tuberculosis (MDR-TB): Tuberculosis is caused by Mycobacterium Tuberculosis that is RESISTANT t to at least two of the most potent TB drugs, Isoniazid and Rifampin

Question 80

What is the most common cause of hospital-acquired infections?

Answer 80

Clostridium difficile (bacteria)

Question 81

How are epidemic C. difficile strains different than other C. difficle strains?

Answer 81

Clostridium difficile- is the MOST COMMON cause of hospital-acquired infections
-Epidemic C. difficile produce More TOXINS and are more RESISTANT to antibiotics
difficile- difficult to grow in culture

Question 82

Discuss the incidence of Ebola virus disease, including its symptoms and characteristics

Answer 82

Ebola virus Disease (formerly known as Ebola Hemorrhagic fever)
-Ebola virus causes fever, hemorrhaging and blood clotting
-First identified (1976) near Ebola River, Congo
-Outbreaks occur every few years (2 outbreaks in 2021)
-50-90% death rate
-Transmitted human to human via blood/body fluids/tissue

Question 83

Discuss the current vaccine used against Ebola virus disease

Answer 83

Ebola Virus Disease
-ERVEBO is currently the only FDA-approved vaccine (12/19) available to prevent EVD. It doesn’t contain the whole virus.
Rather, it is a VIRAL VECTOR carrying a single gene specific to the Zaire strain of ebolavirus
-several other vaccines are in development

Question 84

Discuss the incidence of the Marburg virus and its similarity with EVD. Where did most outbreaks occur and why?

Answer 84

Marbug virus
-another HEMORRHAGIC Fever virus with clinical symptoms almost indistinguishable from Ebola Hemorrhagic fever
-first noticed during small outbreaks in several German cities (ex: Marburg) in the 1960s (began with lab workers that handled African green monkeys)
-Most outbreaks in African (NO vaccine)
-RARE: 13 outbreaks in Africa since 1975 killing 1 to 252 people
-Transmitted human to human like EVD, but has also occurred by handling ill or dead infected green monkeys and fruit bats

Question 85

what is the natural resevoir for Marburg Virus?

Answer 85

African Fruit bats are the Natural reservoir for Marburg virus. Although not proven, bats are the likely reservoir for EBOLA virus as well

Question 86

What is the Zita Virus disease? When was it discovered and

Answer 86

Zika Virus disease:
-Although discovered in 1947, in the Zika forest of Uganda, it didn’t make world headlines until 2005
-Virus is spread to people primarily through the bite of an infected AEDES species mosquito
-Many people infected with the virus won’t have symptoms or will only have mild symptoms
However, the Virus can pass from a pregnant woman to her fetus during pregnancy or around time of birth and is linked to problems, such as miscarriage, stillbirth, and birth defects

since 2017- No current local transmission of Zika virus have been reported in the continental United States
-In 2016, and 2017, local mosquito-borne transmission of Zika was reported in FLORIDA (N= 220) AND Texas (N= 11)

Question 87

What is the Middle East Respiratory Syndrome (MERS) ? Where was the virus first reported?

Answer 87

Middle East Respiratory Syndrome (MERS)
-Respiratory illness also known as CAMEL flu (believed camels involved in spread but unclear how)
-Caused by a new member of the coronavirus family called Middle East respiratory syndrome coronavirus (MERS-CoV)
-first reported in Saudi Arabia in 2012, spread to Europe and Asia, and two travel-associated cases occurred in US in 2014

Question 88

Discuss whether you should follow what advertisements tell you about bacteria and what is needed to buy?

Answer 88

Advertisements tell you that bacteria and viruses are all over your home and that you need to buy antibacterial cleaning products.
-You Should NOT buy antibacterial products; you can wash your hands

Question 89

Explain why FDA banned sale of non-medical soap in 2017

Answer 89

In September 2016, the FDA announced that effective in September 2017, it would PROHIBIT the sale of non-medical soap containing triclosan or 18 other ingredients marketd as antimicrobials due to FDA’s findings of the lack of efficacy in these products