Micro exam #1 study guide Johnson

Causes of death in the United States in the1900s: microorganisms

influenza and pneumonia

tuberculosis

gastroenteritis

diphtheria

typhoid fever

syphilis**

etc

Virulence

the degree of damage or disease severity that a pathogen (such as a bacterium, virus, or fungus) can cause to its host

much of the virulence of bacterial (and other microorganism infections) can be blamed by ________

the host - the immune system is what kills us 12-29% of the time

Who invented pasteurization, and what else did he invent?

Louis Pasteur

He developed the vaccines for rabbies and anthrax

Who is Robert Koch?

Founder of bacterialology

Coined Koch’s postulates for identifying dieases causing bacteria

1. microorg must be found in abundance in all orgs suffering from it, but should not be found in healthy orgs

2. microorg must be isolated and grown in a pure culture

3. microorg must be inoculated into a healthy specimen - specimen must suffer from the disease

4. microorg must be sampled from inoculated and identified as original causing microorg

Who discovered cells

Robert Hooke

Developed the microscope

Antoine Von Leeuwenhoek

Childbed fever

Puerperal fever

Difference between chemically defined, complex media, and simple media?

Chemically defined is media in which you know all the ingredients

Complex media is media that at least one ingredient is not chemically definiable

Simple media contains carbon and maybe salts

Selective vs differenital media

Selective - contains agents to inhibit growth of unwanted specimens to focus on a particular specimen

Differential - allows the growth of multiple selected specimens, but in a way that distinguishes them from each other

Microorganism can be indentified through:

1. Microscopic appearance

2. characterization of cellular metabolism

3. determination of products given off in growth, use of enzymes, and how they get energy

4. Genetic and immuelogical characteristics

capsule

bound more tightly to the cell denser and thicker than a slime layer. visible by negative staining. capsule drives massive immune responses

gram positive bacteria

cellular membrane/thick cell wall

gram negative bacteria

cellular membrane/ thin cell wall/outer membrane

gram intermediate/acid-fast bacteria

cellular membrane/ intermediate cell wall of unusual

non gram stainable

cellular membrane/no cell wall

envelope

outer cover for the bacterial cell (composed of all cell coverings not just the cell membrane)

what features do all bacterial cells possess?

cell membrane

cytoplasm

ribosomes

cytoskeleton

one/few chromosomes

what features do most bacterial cells possess?

cell wall

glycocalyx

what features do some bacterial cells possess?

flagella,pilli,fimbriae

outer membrane

plasmids

inclusions

endospores

intracellular membranes (organelles)

universal trait to all living organisms

water

polyamines (putrescine and spermine)

breakdown of amino acids. coat the bacterial cell with a (+) charge so that other molecules that are (+) don't grab hold of the (-) charges cell. aka: environmental protection

They help produce biofilm

pleomorphism

cells of one species may vary in shape and size

Differences in a prokaryotic and eukaryotic flagella

Prokaryotic

1. Propeller movement

2. ion motor

3. not covered by cell membrane

Eukaryotic

1. Covered by cell membrane

2. Made of microtubules

3. ATP powered

4. Wave like motion

name the types of flagellar arrangements

monotrichous-single flagellum

lophotrichous-small bunches or tufts of flagellum

amphitrichous-flagella at both poles

peritrichous-flagella dispersed randomly

How to bacteria move towards a stimulus?

Chemotaxi: what attracts and causes the movement (stimulus)

Triggers the recepters to bind extracellular molecules (causing rotation of flagella)

Runs: cell moves towards stimulus

Tumbles: how the cell stops

pili

used for atachement and genetic exchange during conjunction

pili pore

a route of entry for antibiotics into the cell

pilE and pilS

pil E is recognized by the immune system and is destroyed but the pilS functions the same and has several different forms so that the immune system will not detect it

glycocalyx

composed of polysaccharides proteins or both. used to avoid phagocytosis/opsonization and for adhesion (biofilms) (makes them hard to detect)

crystal violet stain (+/-)

both cell walls stain with the dye

grams iodine (+/-)

dry crystals trap in the gram + cell but there is no effect for the gram negative

alchohol decolorizor (+/-)

crystals remain in the gram positive cell and in the gram negative bacteria the outer membrane is weakened and the stained crystals loose dye

safranin (+/-)

the red dye has no effect on the gram positive bacteria but it stains the gram negative red

gram positive cell envelope

capsule is mostly polysaccharides, peptidoglycan staining at the surface.

gram negative cell envelope

capsule is mostly polysaccharides, peptidoglycan is stained in the middle

Mycobacterial cell envelopes

(mycobacterial also means acid fast and gram terminate bacteria). capsule (sugar), mycolic acids, arabinan, galactan, peptidoglycan, then the cell membrane

mycoplasma cell envelope

the cell walls are only present because of osmotic pressure that prevent the bacteria from lysing. cholesterol is important; the group of sterols provide more rigidity to keep from lysing

basic structure of the cell membrane

phosphoryl head group, glycerol derivative, and fatty acid side chains

passive transport

molecules move along their concentration gradient

active transport

molecules move against their concentration gradient (requires energy)

what do proteins provide for the cell membrane

structure, signaling pathway, ion transport, general transport, secretion systems

Types of protein structures

1. Primary - linear

2. Secondary - bending

3. Tertiary

4. Quaternary

Composed of amino acids

cytoplasmic membrane

provides a site for reactions especially atp synthesis

proton motive forces (PMF)

constant H+ is pumped out of the cell (used to power ATP)

efflux pumps

span the inner and outer membrane and some derive their power to export antimicrobial agents from the PMF

sterols

the eukaryotic membrane reinforcement agent

hopanoids/hopanes

the prokaryotic membrane reinforcement agent

cell wall function

provides rigidity to the cell. allow it to withstand osmotic shock or pressure

Prokaryotic shapes

Coccus - round

Bacillus - rod

Vibrio - curved rod

Spirillum - slighty curved or spiral shaped

Spirochette - looks like a spring

Branching filaments - look like branches

Lipopolysaccharide (LPS)

gram - bacteria have LPS on the outer membrane; when LPS is detected blood is sent to these locations. the organism gets the Fe2+ content it needs but causes the host to deteriorate (most dont mean to do it)

endotoxin

strengthening agent inside the cell (LPS)

pyrogen

a fever-producing substance (LPS)

Lipooligosaccharide (LOS)

when in the blood stream can become deadly and reduces the cells ability to perform apoptosis causing the cells to rupture capillaries

shape determining proteins

ftsZ=cocci

MreB=bacilli

Thylakoids

extenstively folded intracellular membranes that produce atp in plant cells

gas vesicles

to increase buoyancy

storage granules

glycogen, phb and pha for energy; sulfur for oxidation

Disease causing Eukaroyte cells

1. Protozoa

2. Fungi

3. Helminths

4. Algae

Cilia

Similar but smaller than flagella, normally a ton of them

• move in an oar like movement

• Found in the esaphogus

How Fungi eat

• thrive in nutrient poor enviroments (dummies)

• Heterotrophic: acquire food from broad ranges

• Saprobic: acquire food from dead plants and animals

• parasitic

How do fungi grow?

Most grow in loose association/colonies

Components of fungi

Mycelium: mass of hyphae that makes up colony body

Septa: segments or cross walls that allow the transport or organells and nuterients across compartments

What are fungal infections called and where can they be found?

Mycoses - typically scalp, nails, skin, mucosal membranes

Algal infections

We know of parasitic green algae - these algal infections are largely unknow, and we are unsure how to treat them

Shellfish poisoning (ASP)

Protozoa

Most are harmless, some are parasitic

• cytoplasm is divided into endo and ectoplasm

• Can maintain shpae constantly, or constantly change shape

PRotozoa habitat and feeding

• Hetertrophs

• Some species have oral grooves for feeding

• some are free range

• some absorb food through the membrane

• requirement for growth is availability of moisture

Protozoa reproduction cycle

• binary fission or sexual reproduction

• cycle - cyst (like spore), trophozite

Protozoa poisonings

Diarrheal, paralytic, and neurotoxic shellfish poisonings

Viruses

• infect all taxonimic groups - even bacteria

• most abundant biological entity

• Influence the human and bacterial genome

Viral envelope

Viruses that form envelopes from host cell membranes, nuclear envelope, or endoplamsmic reticulum

they are pleomorphic

Components of a virus

1. Viron: fully formed virus

2. Nucleocapsid: capsid with a nucleic acid

3. capsid: protein shell that surrounds ncleic acid

4. Spikes: help virus connect to host cell

5. are either symmetrical, asymmetrical

General phase of animal cell virus infection/replication cylce

1. Absorption

2. Penetration

3. Uncoating

4. Synthesis

5. Assembly

6. Release

Host range

Limited types of cells virus can infect

Tropism

Specific viruses for specific tissues

Cytopathic effects

Damage to host cell from virus

• change in shape (deformed)

• develop of intercellular changes

• inclusion bodies

• syncytia

auxotroph

an organism that is deficient in the ability to synthesize an essential organic compound from the constituent parts

Provirus

Persistent infection in which the viral DNA in incorporated in the hosts DNA

Chronic latent state of a virus

Virus goes dormant and comes back when induced by stress

Oncoviruses

Viruses that cause cancer - thought to be an accident but the cause tumors

Epstein Barr Virus

Phage

Viruses that infect bacteria - known as bacteriophage

• Can make bacteria more pathogenic

• virophages are phages that infect other viruses

• We use plaques to watch virus growth

Prions

• spongiform encephalopathies

• in human - Creutzfeldt Jacobs’s Disease (CJD)

• in cows - mad cow disease

Viroids/Satellite Viruses

• Viruses that infect plants

• Made up of strands RNA - naked viruses

• Certain viroids (AAV) can cause Hep D, but only in the presence of Hep B

How to cultivate viruses

• viruses require living cells to replicate

• In vivo - living animals used as host

• in vitro - test tubes

essential nutrient

any substance that an organism can not make itself and must be provided to the organism

macronutrients

required in relatively large quantities and play principal roles in cell structure and metabolism

ex.. C, O, N, H, P, S necessary for protein fxn.. Mg2+ Ca2+, Fe2+, K+

micronutrients

trace elements, required in small quantities and involved in enzyme function and maintenance of protein structure---> Co Cu Mn Zn

Inorganic nutrient

an atom or simple molecule that contains a combination of atoms other than carbon and hydrogen

organic nutrients

contain carbon and hydrogen atoms and are the products of living things

ex.. carbohydrate, lipids, proteins, nucleic acids

Essential elements

Macro-elements

Na: cell transport

Ca: stabilizer of cell wall and endospores of bacteria

Mg: component of chlorophyll, stabilizer of membranes and ribosomes, involved in several enzymatic reactions involving an active site

Micro-elements

copper, cobalt, nickel, molybdenum, iodine, etc- needed in small amounts by microbes

(needed in small amounts but large amounts are toxic)

nutritional immunity

the withholding of critical nutrients from a pathogen by the host ex. Fe

____________ is the limiting nutrient during infection by a pathogen

Fe

heterotroph

organism whose carbon source must be organic

autotroph

organism whose carbon sources is inorganic

phototroph

microorganisms that photosynthesize

chemotroph

microorganisms that gain energy from chemical compounds

lithotroph

organism that uses inorganic molecules

organotroph

organism who uses organic molecules

chemoheterotrophs

majority of microbes that cause human disease

saprobes

free living organisms that feed on organic debris