Chapter 1: The Microbial World And You Flashcards
Microbe
“Microorganism”
Very small organism- microscope needed
Autotroph(self-feeders)
(Human) microbiome
“Microbata”
Group of microbes
-in and out if our bodies
-keeps us healthy
Staphylococcus aureus
Bacteria
Location: nasal epithelial cells
Generally live harmlessly on or inside nose
Exception: misuse of antibiotics
➡️ survival of bacteria w/ antibiotic resistance genes
-ex. Methicillin-resistant S. Aureus (MRSA)
Cocci(spherical)
Signs
Objective changes observed and measured by healthcare practitioners
Ex. Ring-like rash- sign of infection
Symptoms
Changes felt by pt
Subjective
Not measurable by an observer
Ex. Itchy, burning skin
Bacteria
Simple-celled
Prokaryotic (no nucleus or organelles) organisms
Contain peptidoglycan (carb and protein complex) in cell walls
3micrometers
Reproduce asexually via binary fission
Shape: coccus, bacillus, or spiral-shape
-important in dx
Genetic info: DNA
Lipid bilayer: present
Ribosome: small, unique
RNA polymerase: simple, 5 subunits
Grow w/o outside help: yes
Max # of cells: 1
First cells on earth
Contain over 50 different phyla (major groups)
Most abundant form of life- no matter bacteria growing in/on humans than they have human cells
Antibiotic sensitivity: Yes
Nutrition source: organic chemical (derived from dead or living organisms); photosynthesis; inorganic substances
Motile: flagella
Binary fission
type of asexual reproduction where a cell splits into two identical daughter cells
Used by bacteria
Cocci
Spherical
Of arranged in clusters or chains
Fungi
-eukaryotes
-reproduce sexually and asexually
-true fungi contain chitin (carb) in cell walls
-nutrition source: absorption of organic material from their environment
-yeast- unicellular fungi
-larger than bacteria
-oval-shaped
-mold- multicellular fungi
-composed of long filaments of cells (hyphae) that branch and intertwine to form visible masses (mycelia)
Branch-intertwined nucleated hyphae may indicate
A fungal infection like Tinae corporis (ring worm)
-cause by fungus: Trichophyton rubrum
-anti fungal cream
Nomenclature: Genus; species naming
Genus: capitalized and italicized or underline
Species: noncapitalized and italicized or underlined
Trichophyton (genus) rubrum (species)
Abbreviation: T. rubrum
Established by Carolus Linnaeus in 1735
Protozoa
-unicellular eukaryotes
-5 micrometers
-most live on their own
-exception: some- parasitic, requires host for nutrients
-motile- via flagella,cilia, pseudopods
-some are photosynthetic (ex. Euglena)
-reproduce sexually or asexually
Bacilli
Rod-shaped
Helminths
-parasitic worms
-eukaryotic
-0.7mm
-adult: macroscopic
-child: microscopic
-dx of tapeworm infection requires microscopic observation of eggs in feces
Spirilli
Spiral-shaped
Viruses
-acellular
-ultra small particles
-contain a core made up of DNA and RNA surrounded by a protein coat
-require host to reproduce
-strict parasites of other forms of life
-many feel viruses are not alive as they are obligate parasites and cannot replicate w/o other cells
-reproduce by using cellular machinery of other organisms- considered living only when they multiply in host cell they infect
Microbiology
Study of living things too small to be seen w/ naked eye
1) bacteria
2) archea
3) eukaryota
4) viruses
Antibiotics
Chemicals naturally produced by bacteria or fungi to act against bacteria
Pleomorphic
Multiple shapes are possible
Pathogen
Microorganism or other substance that can cause disease in a host organism
Infectious disease
Condition caused by invasion and multiplication of microorganisms in a living host
List several ways in which microbes affect our lives
1) Important in maintaining Earths ecological balance.
-marine/freshwater: form basis of food chain in oceans, lakes, and rivers
-soil: breakdown wastes and incorporate nitrogen (g) from air into organic compounds➡️ recycle elements among soil, H2O, living organisms, and air
2) Live in humans and other animals and are needed to maintain good health.
3) Are used to produce foods and chemicals
-vitamins, organic acids, enzymes, alcohols, and many drugs
-acetone, butanol,vitB2 (riboflavin) and B12 (cobalamin)
4) Can cause disease.
5) photosynthesis
6) enzymes in microbes can be manipulated to cause microbes to produce substances they normally don’t synthesize
-cellulose, insulin, and proteins (for vaccines)
Explain the importance of observations made by Hooke and van Leeuwenhoek
- Robert Hooke observed that cork was composed of “little boxes”; he introduced the term cell (1665).
- Hooke’s observations laid the groundwork for development of the cell theory, the concept that all living things are composed of cells.
- Anton van Leeuwenhoek, using a simple microscope, was the first to observe microorganisms (1673).
-microorganisms, living beings he characterized as “animalcules” (little animals)
Spontaneous generation
1) Until the mid-1880s, many people believed in spontaneous generation, the idea that living organisms could arise from nonliving matter.
2) Francesco Redi demonstrated that maggots appear on decaying meat only when flies are able to lay eggs on the meat (1668).
3) John Needham claimed that microorganisms could arise spontaneously from heated nutrient broth (1745).
4) Lazzaro Spallanzani repeated Needham’s experiments and suggested that Needham’s results were due to microorganisms in the air entering his broth (1765).
5) Rudolf Virchow introduced the concept of biogenesis: living cells can arise only from preexisting cells (1858).
6) Louis Pasteur demonstrated that microorganisms are in the air everywhere and offered proof of biogenesis (1861). S-shaped flask
7) Pasteur’s discoveries led to the development of aseptic techniques used in laboratory and medical procedures to prevent contamination by microorganisms.
Identify the importance of Koch’s Postulates
discovers bacillus anthrasis
prove that specific mocrobes casue specific disease
Criteria used to determine the causative agent of infectious disease
1. The causative agent must be isolated in every case of the disease, but absent from those who are healthy.
- The causative agent must be cultured outside the host.
- When injected into a healthy, susceptible host, the host must get the disease.
- The pathogen must be isolated from the once healthy host when it becomes sick, and must be shown to be the original organism.
Identify the importance of Jenner’s work
1) In a vaccination, immunity (resistance to a particular disease) is conferred by inoculation with a vaccine.
2) In 1798, Edward Jenner demonstrated that inoculation with cowpox material provides humans with immunity to smallpox.
3) About 1880, Pasteur discovered that avirulent bacteria could be used as a vaccine for fowl cholera; he coined the word vaccine.
4) Modern vaccines are prepared from living avirulent microorganisms or killed pathogens, from isolated components of pathogens, and by recombinant DNA techniques.
Identify the importance of Fleming’s work
Alexander Fleming observed that the Penicillium fungus (mold) inhibited the growth of a bacterial culture. He named the active ingredient penicillin (1928).
Penicillin has been used clinically as an antibiotic since the 1940s (when 2nd Golden Age of Microbiology began)
Identify the importance of pasteur’s work
Pasteur became a pioneer in the development of vaccinations- the introduction into the body of a mild (attenuated) form of a pathogen to produce immunity from the more harmful strain of the disease.
He developed vaccinations for anthrax and fowl cholera, but his rabies vaccine was the most famous.
Identify the importance of Redi’s work
Francesco Redi is recognized for his significant contribution to biology by conducting one of the first controlled experiments that effectively disproved the theory of spontaneous generation, demonstrating that maggots on decaying meat arise from flies laying eggs on it, not from the meat itself
this established the concept that life only comes from pre-existing life, marking him as a pioneer in experimental biology and parasitology
Identify the importance of Semmelweis’ work
Ignaz Semmelweis is credited with significantly contributing to the field of medicine by discovering the importance of handwashing in preventing the spread of infection, particularly in the context of childbed fever (puerperal fever), which he identified as being transmitted by doctors who did not properly sanitize their hands after performing autopsies, leading to a dramatic reduction in maternal mortality rates when he implemented mandatory handwashing with a chlorinated lime solution among medical staff.
Identify the importances of Lister’s work
Joseph Lister helped introduce germ theory and laid the foundation for the use of antiseptics in the practice of medicine and surgery. Today, asepsis and sterile techniques have replaced antisepsis as the principal method in combating wound infection
Identify the importance of Koch’s work
-Koch established the principle that specific pathogens cause specific diseases, which was a major advancement in medical microbiology.
-He developed agar plates for culturing bacteria, allowing for the isolation and identification of pathogens.
-Koch’s postulates outline a four-step process to establish a causal relationship between a microbe and a disease, which includes:
1) The same pathogen must be present in every case of the disease.
2) The pathogen must be isolated and grown in pure culture.
3) The cultured pathogen must cause the disease when introduced to a healthy organism.
4) The pathogen must be re-isolated from the inoculated, diseased host.
Identify the importance of Needham’s work
John Needham’s main contribution to science was his experiment attempting to prove the theory of spontaneous generation by boiling broth, which he believed would kill existing microbes, then sealing the flask and observing the later growth of microorganisms, leading him to conclude that life arose spontaneously from non-living matter
However, his experiment was later disproven by other scientists who showed that he did not adequately sterilize the broth, highlighting a flaw in his methodology.
List the 3 domains to classify organisms
1) bacteria
2) archae
3) eukarya
Biofilm
Cultures (usually mixed) that are stuck to a surface
Often more resistant than single colonies and have health and environmental issues
Prions
Abnormal forms of naturally occurring proteins in the brain that cause various neurodegenerative diseases (transmissible spongiform encephalopathies (TSEs))
Archaea
Most common in extreme environments
-combine feature of prokaryotes and eukaryotes
-extremophiles; some will grow when other organisms cannot
-halophiles: salt loving
-sulfophiles: sulfur loving
-thermotropes: heat loving
-lithotrophs: rock loving
-methanophiles: methane loving
Antibiotic sensitivity: No
Does not cause disease in humans
Eukarya
Single celled (yeast, algae, and amoebas) or multicellular (fungi, plants, and animals
Contain membrane-bound sub compartments that separate specific functions, particularly the nucleus
Division includes microscopic organisms previously belonging to the Monera kingdom
Antibiotic sensitivity: No
No cell wall
Pathogen
Disease-causing
Bactericides
Bacterium commonly found in large intestine
Horizontal gene transfer
movement of genetic material between organisms that are not related by parent and offspring
Bacteria’s ability to swap genes w/ other genes
Normal microbiota
“Normal microbiota”
Microorganism that colonize a host w/o causing disease
Transient microbiota
Microorganisms that are present in an animal for a short time w/o causing a disease
coli-
Of the large intestine
entero-
Found in intestines
pyo-
Forms pus
cerevisia
Make beer
chryso
Produce yellow pigment
Antibiotics
Can treat bacterial infections
No effect on viruses
Algae description
-photosynthetic eukaryotes
-wide variety of shapes
-reproduce sexually and asexually
-unicellular (ex. Diatoms) or multicellular (ex green algae)
-cell walls composed of cellulose (carb)
-photosynthetic
-do not require organic compounds from environment
Multicellular animal parasites
-not strictly microorganisms
-eukaryotes
1)parasitic worms= flatworms
2)helminths= roundworms
-early life: microscopic
Cellular organization of organisms
By Carl Woese in 1978
1) bacteria (cell walls contain a protein-carb complex- peptidoglycan)
2) archaea (cell walls, if present, lack peptidoglycan)
3)eukarya
-protists (slime molds, protozoa, and algae)
-fungi (unicellular yeasts, multicellular molds, and mushrooms)
-plants (mosses, ferns, conifers, and flowering plants)
-animals (sponges, worms, insects, and vertebrates)
Robert Hooke importance
1665- observed thin slice of cork through crude microscope
Conclusion: life’s smallest unit: cells
Hooke used improved microscope and saw individual cells➡️ marked beginning of cell theory
-“all living things are composed of cells”
Anton van Leeuwenhoek importance
First to observe microbes
(1673-1723)- wrote about “little animalcules”- bacteria and Protozoa
Fermentation
Process discovered by Pasteur in which microbes called yeast convert the sugar to alcohol in the absence of air
-souring and spoilage of wine and beer caused by bacteria
-in the presences of air, bacteria changes alcohol into vinegar (acetic acid)
Algae
Not plants- no stems, leaves, or vascular system to transport water and nutrients throughout their body
Unicellular or multicellular
Motile
Do not make flowers or seeds
Green algae contain chloroplasts and cellulose in cell walls composed
Chemotherapy
Treatment of disease using chemical substances
For noninfectious diseases (ex. Cancer)
Synthetic drugs
Chemotherapeutic agents prepared chemicals in lab
The success of chemotherapy is based on the fact that some chemicals are more poisonous to microorganisms than to hosts infected by the microbes
By 1930s several synthetic drugs- most derive red from dyes along w/sulfa drugs
Paul Ehrlich importance
-(1910)
-found salvarsan (chemotherapeutic agent; arsenic derivative effective against syphilis)
-not “magic bullet”
Alexander Fleming importance
-1928, penicillin, an antibiotic (substance that is made by organism (ex. Mold))- ➖growth of another organism, was discovered
Negative effects of antibiotics
-many anti microbial chemicals kill infected host as well pathogenic microbes
Viral growth
Process by which a virus replicates itself w/in host cell
Why is there very few successful antiviral drugs?
B/c a drug that would interfere w/ viral reproduction would also likely affect uninfected cells of the body
Bacteriology
-study of bacteria
-began w/ van Leeuwenhoeks first exam of tooth scrapings
Heide Schultz importance
1997- discovered bacterium (Thiomargarita namibiensis)large enough to be seen w/ unaided eye (0.2mm wide)
-lives in mud on African coast
-consumes hydrogen sulfide- toxic to mud-dwelling animals
Mycology
Study of fungi
Parasitology
Study of Protozoa and parasitic worms
Parasitic diseases have recently been found in pts whose immune systems have been suppressed by organ transplants, cancer therapy, or AIDS
Immunology
Study of immunity
Smallpox vaccine was so effective that the disease has been eliminated
Rebecca Lancefield importance
1933- proposed that streptococci be classified according to serotypes (variants w/in a species) based on certain components in the cell walls of bacteria
Allowed for prevention of the variety of diseases caused by Streptococcus pyogenes
-strep throat
-scarlet fever
-septicemia (blood poisoning)
Interferons
Substances generated by the body’s own immune system
Discovered in 1960s
➖replication of viruses and have triggered considerable research related to the treatment of viral diseases and cancer
Virology
Study of viruses
Originated during First Golden Age of Microbiology
Dimitri Iwanowaski importance
1892- reported that the organism that caused mosaic disease was so small that it passed through filters fine enough to stop all known bacteria
At the time he was not aware that organism in question was a virus
Mosaic disease
plant disease caused by viruses that cause leaves to develop a mottled, discolored appearance
Wendell Stanley importance’s
1935- demonstrated that the organism (tobacco mosaic virus (TMV)) was fundamentally different from other microbes and so simple and homogeneous that it could be crystallized like a chemical compound
Facilitated the study of viral structure and chemistry
e-microscope
1930s
Observation of the structure of viruses in detail
Microbial genetics
Studies the mechanisms by which microorganisms inherit traits
Molecular biology
Looks at how genetic info is carried out in molecules of DNA
Who demonstrated relationship between genes and enzymes?
George W. Beadle and Edward L. Tatum
Conjugation
When genetic material is transferred from one bacterium to another
Discovered by Joshua Lederberg and Edward L. Tatum
Genomics
Study of all of an organism’s genes
Allows scientists to classify bacteria and fungi according to their relationships with other bacteria, fungi, and Protozoa
Joseph Lister importance
Applied disinfectant phenol to surgical dressings
Joseph Lister importance
Applied disinfectant phenol to surgical dressings
Joseph Lister importance
Applied disinfectant phenol to surgical dressings
Ignaz Semmelweis
Showed the importance of handwashing to reduce puerperal (child fever) infections
Smallpox cause by…
Virus
Smallpox cause by…
Virus
R
Who proved germ theory?
Robert Koch
members of which genus of bacteria are best stained using acid fast method
Mycobacterium
While _ bacteria retain carbol fuchsin after acid-alcohol treatment, _ bacteria’s decolonized by acid-alcohol
Acid-fast; non-acid-fast
thick waxy layer of what substance in the cell wall constitutes the major portion of the mycobacterial cell wall, separating it from other microorganisms?
Mycolic acids (lipoidal)
What color do you expect Escherichia coli to be after performing the acid-fast stain?
Blue
What color would you expect Mycobacterium smegmatis to be after performing the acid-fast stain?
Red
What is the purpose of heating a slide during the staining process?
Allows for further penetration of the stain through the lipoidal wall and into the cytoplasm
Loss of bent, or refracted, light results in a reduced numerical aperture, which diminishes the resolving power of the objective lens. Adding which of the following substances between the slide and the lens acts to decrease the refraction of light?
Oil
Microbes and human welfare
A.Recycling Vital elements (nitrogen, hydrogen, carbon, sulfur)
1.Nitrogen, carbon, and oxygen cycle
2.Sewage Treatment
B.Bioremediation
1.Definition: Bacteria (bacillus or pseudomonas) degrade or detoxify pollutants such as oil and mercury
C.Biological Insecticides
D.Modern Biotechnology and Genetic Engineering
Microbes and human diseases
A.Normal Microbiota or Normal Flora (Human Microbiome) are bacteria and yeast present in and on the human body, causing no harm.
- Benefits: digestion, synthesis of vitamins, growth factors; nonspecific defenses (innate); microbial antagonism
B.Biofilms
Definition: complex aggregation of microbes; attach to each other and surfaces in contact w/ water
C. Pathogens (disease-causing organisms)
D.Susceptible Host- an organism in which the pathogen causes disease
E. Opportunistic Pathogens (potentially pathogenic organisms)- immunocompromised persons more susceptible
1. Examples: E. coli (bacteria) and yeast > U.T.I.
F.Resistance is the ability of the body to ward off disease.
Resistance factors include skin, stomach acid, and antimicrobial chemicals
How are biofilms beneficial and harmful?
Biofilms may be beneficial:
- Protect mucous membranes from harmful microbes
- In lakes are an important food source for aquatic animals
Biofilms may be harmful:
- Biofilms can form on teeth (dental plaque), contact lenses,
and catheters - Microbes in biofilms are more resistant to antibiotics and disinfectants
- Microbes in biofilms are protected from host’s defenses
