a localized collection of pus in any part of the body that is surrounded by inflammation; often a symptom of various bacterial infections

antibiotic resistance that arises from mutations in the pathogen or that is acquired from some other pathogen via DNA gene exchange; either case leads to new variants of the original pathogen which can become more powerful over time

entails the introduction of a foreign molecule into the body (naturally or artificially by injection), which causes the body to generate immunity against the target through the production of T cells and B cells (with their antibodies) specific to the antigen; this is different from passive immunization where pre-synthesized elements of the immune system are transferred to a person (ex: mother to fetus)

adaptive immune response provides the immune system with the ability to recognize and remember specific pathogens and to mount stronger attacks each time the pathogen is encountered

natural or synthetic compounds that block essential microbial-specific functions (DNA replication, protein synthesis, cell wall synthesis etc.) with the goal of inhibiting or eliminating microbial growth

occurs when the combination of two or more antibiotics generates a combined effect that is greater than the sum of their individual effects

occurs when one antibiotic, usually the one with the least effect, interferes with the effects of another antibiotic

any substance that inhibits the growth of bacteria, in contrast to a germicide, which kills bacteria outright; antiseptics are not considered to include antibiotics, which are usually taken internally; ex: alcohol, iodine, chlorhexidine

a device for effecting sterilization by steam under pressure; it uses steam heated to 121° C at 103 kPa above atmospheric pressure,for 15 minutes; the steam and pressure transfer sufficient heat into organisms (even spores) to kill them

describes a compound that kills bacteria and ideally nothing else; bactericides include disinfectants, antiseptics and antibiotics

describes a compound capable of inhibiting the growth or reproduction of bactéria; different from bactericidal (capable of killing bacteria outright)

a virus that infects bacteria; given it is a virus, it is acellular and cannot grow outside the bacteria; composed of a protein outer shell called a capsid, may include a tail, and contains single or double stranded DNA or RNA

enzymes produced by some bacteria that are responsible for their resistance to beta-lactam antibiotics (ex: penicillin); these enzymes break the beta lactam ring found in these antibiotics

inhibits activity of beta-lactamase, a protein that provides resistance to beta-lactam antibiotics; often given in conjunction with these antibiotics

group of organisms having the same or nearly the same genotype, such as a particular strain of bacteria

  an optional outermost layer of protective covering of bacterial cells (Gram + or -) that is composed of polysaccharides; can protect against complement activation or phagocytosis of the cell

  furuncles (infected hair follicles) that have spread together and form infection under the skin and can cause the wound infections; caused by Staph. Aureus

layer surrounding the cell membrane composed of peptidoglycans; serves as an osmotically resistant barrier, is entirely responsible for the shape of the bacteria, and serves as the basis for the Gram stain (differences in thickness lend different result); can be affected by antibacterials

 is relatively similar in most bacteria and has standard lipid bilayer characteristics/functions (permeability barrier, active transport, etc.); affected by antibacterials, detergents, polymyxins, and ionophores

(cell-mediated immunity?) - an immune response that does not involve antibodies or complement but rather involves the activation of macrophages, natural killer cells (NK), antigen-specific cytotoxic T-cells, and the release of various cytokines in response to an antigen

a diffuse inflammation of connective tissue with severe inflammation of dermal and subcutaneous layers of the skin; can be caused by normal skin flora or by exogenous bacteria, and often occurs where the skin has previously been broken: cracks in the skin, cuts, blisters, burns, insect bites, surgical wounds, or sites of intravenous catheter insertion

the segment of DNA that contains all the information for production of single polypeptide

a series of three adjacent bases in a DNA or RNA molecule, which codes for a specific amino acid

the transfer of genetic material between bacteria through cell-to-cell contact (as opposed to transformation or transfection).  Bacterial conjugation is often regarded as the bacterial equivalent of sexual reproduction or mating. However, it is not actually sexual, it is merely the transfer of genetic information from a donor cell to a recipient.

organisms that colonize humans (whether for a short period such as hours or days [transient] or permanently) do not interfere with normal body functions.

relationship between two organisms where one organism benefits but the other is unaffected; human floral may be commensal.

a biochemical cascade made up of protein fragments that helps, or “complements” the ability of antibodies to clear pathogens from an organism; part of the innate immune system (not adaptable and does not change over the course of an individual's lifetime); can be recruited and brought into action by the adaptive immune system; targets bacteria and viruses for removal and can kill pathogens by punching holes in them

master regulators of the immune system: help cycling of stem cells into progenitor cells, control differentiation of T/B cells into effector cells; important therapeutic reagents; includes interleukins, interferons, chemokines, etc

an agent used to destroy microbes on inanimate objects (ex. phenols, formaldehyde, chlorine bleach)

process of establishing a non-covalent, sequence-specific interaction between two or more complementary strands of nucleic acids into a single hybrid, which in the case of two strands is referred to as a duplex. Oligonucleotides, DNA, or RNA will bind to their complement under normal conditions, so two perfectly complementary strands will bind to each other readily (annealing).

a collection of pus within a naturally existing anatomical cavity, such as the lung pleura (membrane surrounding the lungs); different from an abscess

Part of the outer portion of the cell wall (LPS=Lipid A + polysaccharide) of most gram-negative bacteria.  Endotoxin is released on destruction of the cell wall.

an iron chelating siderophore (high affinity iron chelating compound) released by enteric bacteria (like E. coli and Salmonella) to bind iron and deliver it to the pathogen; if a bacterium cannot make enterobactin, then it cannot grow in the gut

an exotoxin released by microorganisms in the intestines that causes gastroenteritis—form pores in the cell membranes of cells in the mucosal layer; produced by Staphylococcus, Vibrio, and Escherichia coli.

toxin excreted by a microorganism, including bacteria, fungi, algae, and protozoa; can cause major damage to the host

enzymes produced by some bacteria and are responsible for their resistance to beta-lactam antibiotics like penicillins, cephamycins, and carbapenems (ertapenem).  These antibiotics have a common element in their molecular structure: a four-atom ring known as a beta-lactam. The lactamase enzyme breaks that ring open, deactivating the molecule's antibacterial properties. Beta-lactam antibiotics are typically used to treat a broad spectrum of Gram-positive and Gram-negative bacteria. Beta-lactamases produced by Gram-negative organisms are usually secreted.

Frameshift mutation

genetic mutation caused by insertions or deletions in the nucleotide chain so that the reading frame is altered in translation of the codons (triplets)

Furuncle

a boil (or Furuncle) is a deep infection of the hair follicle. It is almost always caused by infection by the bacterium Staphylococcus aureus, resulting in painful swollen area on the skin caused by an accumulation of pus and dead tissue.

stretch of DNA at encodes for a protein

the process by which DNA is transferred from one bacterium to another by a virus.  It also refers to the process whereby foreign DNA is introduced into another cell via a viral vector. This is a common tool used by molecular biologists to stably introduce a foreign gene into a host cell's genome.

set of rules by which information encoded in genetic material (DNA or mRNA sequences) is translated into proteins (amino acid sequences) by living cells. The code defines a mapping between tri-nucleotide sequences, called codons, and amino acids; a triplet codon in a nucleic acid sequence specifies a single amino acid. Because the vast majority of genes are encoded with exactly the same code this particular code is often referred to as the canonical or standard genetic code, or simply the genetic code, though in fact there are many variant codes.

tail-like projection that protrudes from the cell body of certain prokaryotic and eukaryotic cells, and functions in locomotion; Bacterial flagella are helical filaments that rotate like screws; may surround the cell (peritrichous), be at one end (unipolar), or at two ends (bipolar)

carbohydrate sequence that is an essential precursor for the ABO blood group antigens; used to make the A antigen, B antigen, and its structure is unchanged in the case of O groups

Herd immunity

the resistance to invasion and spread of an infectious agent in a group or community, based on the resistance to infection of a high proportion of individual members of the group

the exchange of corresponding stretches of DNA between two sister chromosomes; can be used to repair breaks in the DNA strand; produces genetic diversity during meiosis

B cell immunity; antibody immunity; refers to antibody production and all of the processes that go with it, including cytokine production, memory cell production, isotype switching, etc.

immunity to disease that occurs as part of an individual's natural biologic makeup; mediated by cells capable of immune activity without being stimulated by immunization and without antigen specificity (activated by PAMPs).  It also includes local barriers to infection such skin, stomach acid, mucous, enzymes in tears and saliva, and skin oils.

Any of a group of glycoproteins that are produced by different cell types in response to various stimuli, such as exposure to a virus, bacterium, parasite, or other antigen, and that prevent viral replication in newly infected cells and, in some cases, modulate specific cellular functions

any of various compounds of low molecular weight that are produced by lymphocytes, macrophages, and monocytes and that function especially in regulation of the immune system and especially cell-mediated immunity

refers to Ag on the capsule; antiphagocytic and anticomplementary; may be varied to escape adaptive immunity; used in serotyping

the portion of endotoxin that causes the body’s reaction. (part of lipopolysaccharide = LPS; three portions: O antigen, core polysaccharide, Lipid A)

  endotoxin; makes up the outer leaflet of the gram – cell membrane; causes immune response against these organisms via PAMP recognition; three components: O antigen—core polysaccharide—Lipid A; Lipid A is described above, O antigen is used in serology (i.e. E. coli O157:H7); symptoms: toxic shock, fever, leukopenia, hypotension, acidosis, DIC, and death

In this context, when a bacteriophage confers DNA that encodes a virulence factor to a bacterium, thus making the bacterium pathogenic or enhancing its pathogenicity (e.g. Clostridium diphtheriae exotoxin is phage coded; also Group A strep, as described in Dustin’s part of the study guide part 4A; there are many, many examples of this)

bacterial product used to cut the cell walls of other bacteria. Unlike ß lactams, this can work on non-dividing cells because it cleaves already formed peptidoglycan

a phagocytic leukocyte in the tissue.  An APC

Refers to an antibiotic concentration that is just enough to stop the growth of an organism but not kill it.  Clinically more important than MCC, as long as host has an effective immune system.

Refers to an antibiotic concentration that is just enough to stop the growth of an organism but not kill it.  Clinically more important than MCC, as long as host has an effective immune system.

a substitution of one single DNA base for another so that the codon changes and transcription --> translation encodes another amino acid.

from Chesnokov (Fun I): when very different nucleotide sequences recombine—occurs infrequently; example: repairing double stranded breaks via nonhomologous DNA end joining (i.e. your DNA breaks and the last ditch save is to stick some random DNA ends together; not so good)

a substitution of one single DNA base for another so that the codon changes and transcription à translation encodes a stop codon

bacteria that resides in the body naturally and is not pathogenic. It may be opportunistic, but is usually beneficial: exclude pathogens by occupying niches in the body, provide some vitamins (esp Vit K), elicit a low continuous level of Ab production

portion of LPS used in serotyping (i.e. E.coli O157:H7); varies to escape adaptive immunity

A genetic functional unit that controls production of a messenger RNA; it consists of an operator gene and two or more structural genes located in sequence in the cis position on one chromosome; the genes under one operon are generally useful when transcribed together (i.e. lac operon)

an organism that is normally not pathogenic, but can cause disease when the body is immunocompromised from chemotherapy, another disease (i.e. cancer or HIV), etc; can also cause disease in those who are very old or very young.

an action of opsonins (Ab or portions of complement); they bind to an Ag and thus tag it for phagocytosis

this type of diarrhea is due to the presence of an unabsorbable or poorly absorbable luminal osmols that exert an osmotic pressure effect across the intestinal mucosa, resulting in excessive water output. Because the diarrhea is caused by the solute, it tends to stop during fasting.         

there is naturally aquired passive immunity, which involves the transfer of antibodies from a mother to her infant, and then there is artificially acquired passive immunity, which involves the introduction of antibodies (rather than antigens, which is artificially acquired active immunity) into the body.  These antibodies come from an animal or person who is already immune to the disease.

a.     Backbone of N-acetyl glucosamine and Nacetyl muramic acid (transglycosylation)

b.      Cross-linked by peptide bridges at MurNAc (transpeptidation)

c.      B-lactam antibiotics prevent crosslinking

Lysozyme (hydrolase) - cleaves backbone (M-G)

engulfment of bacteria via invagination of membrane of pathogen to make phagosome which later fuses with lysosome to make phagolysosome.  With this fusion, the pathogen is ingested via heterophagy or autophagy.

- Replicate in cytoplasm, independent of chromosome.Usually circular (borrelia = linear), Few to several hundred kb. Conjugative, antibiotic resistance, metabolic, virulence

the patient already has resistant organisms due to the random statistical chance of having the necessary mutation

   - protein. Shorter, narrower than flagella, Common - peritrichous; attachment, For sex - single; gene transfer (conjugation; gram -)

a regulatory region of DNA located upstream of a gene, providing a control point for regulated gene transcription

Restriction enzymes recognize specific DNA sequences that have a palindromic structure. And cut with sticky or blunt ends

In this type of diarrhea there is abnormal ion transport across the intestinal epithelial cells, which results in increased secretion, decreased absorption, or both. There is no osmotic gap, and as the diarrhea is not related to intestinal contents, it typically does not stop with fasting.  A classic example of acute secretory diarrhea is cholera, and is also seen in infections like enterotoxigenic E coli.

 refers to distinct variations within a subspecies of bacteria or viruses. These microorganisms, viruses, or cells are classified together based on their cell surface antigens

are a family of related toxins with two major groups, Shiga toxins act to inhibit protein synthesis within target cells. Common in Shigella and E. Coli.

Siderophore

greek for iron carrier, is an iron chelating compound secreted by microorganisms. Fe3+ ions have a very low solubility at neutral pH and therefore cannot be utilized by organisms. Siderophores dissolve these ions as soluble Fe3+ complexes that can be taken up by active transport mechanisms. Many siderophores are nonribosomal peptides

DNAmutations that do not result in a change to the amino acid sequence of a protein

The second type of recombination event is called specialized transduction and occurs as a result of mistakes in the transition from a virus' lysogenic to lytic cycle. If a virus incorrectly removes itself from the bacterial chromosome, bacterial DNA from either end of the phage DNA may be packaged into the viral capsid. Specialized transduction leads to three possible outcomes: 1. DNA can be absorbed and recycled for spare parts; 2. The bacterial DNA can match up with a homologous DNA in the recipient cell and exchange it. The recipient cell now has DNA from both itself and the other bacterial cell; 3. DNA can insert itself into the genome of the recipient cell as if still acting like a virus resulting in a double copy of the bacterial genes.

Superantigen

   class of microbial proteins that bind to Class II MHC molecules outside antigen-binding cleft and stimulate CD4 T cells by interacting with all TCRs that display a specific variable region on the b chain-typified by staphylococcal exotoxins

or SOD, catalyzes the dismutation of superoxide into oxygen and hydrogen peroxide.  E. coli contain a form of this enzyme.  SOD is also an effective defence weapon and Mycobacteria and Nocadia have SOD which enables them to resist the injection of superoxide by phagocytes. When these organisms cause serious disease, it takes the body a very long time to win, and depending on the strength of the patient the bacteria may win. Although the enzyme isn't especially fast relative to the spontaneous dismutation of superoxide, the ability of the enzyme to provide some protection to organisms is shown by the existence of a motor neuron disease in individuals who have point mutations in SOD and by the finding that the absence of SOD may lead to a form of anemia. As an enzyme, SOD has particular value as an antioxidant that can help to protect against cell destruction. It has the distinct ability to neutralize superoxide, one of the most damaging free radical substances in nature.  ALS or Lou Gehrig’s disease is related to a mutation in the SOD1 gene.

Teichoic acid

 The cell walls of gram-positive bacteria contain teichoic acids, which consist primarily of an alcohol and phosphate.  2 classes of teichoic acids: lipoteichoic acid, which spans the peptidoglycan layer and linked to the plasma membrane, and wall teichoic acid, which is linked to the peptidoglycan layer. Because of their negative charge, (from the phosphate groups), teichoic acids may bind and regulate the movement of cations (positive ions) into and out of the cell.  They may also assume a role in cell growth, preventing extensive wall breakdown and possible cell lysis.  Finally, teichoic acids provide much of the wall’s antigenic specificity and thus make it possible to identify bacteria by certain laboratory tests.

   if you don’t know this yet you are not gonna make it all 4 years.

a.     Making RNA from DNA in Nucleus

transfer of genetic information between bacteria by means of “naked” intracellular DNA fragments (plasmids) derived from bacterial donor cells and recombination in the recipient chromosome

a point mutation that changes a purine nucleotide to another purine (A ↔ G) or a pyrimidine nucleotide to another pyrimidine

messenger RNA (mRNA) produced by transcription is decoded by the ribosome to produce a specific amino acid chain, or polypeptide, that will later fold into an active protein. Translation occurs in the cell's cytoplasm, where the large and small subunits of the ribosome are located

mutation produced by the insertion of a transposable genetic element.

sequences of DNA that can move or transpose themselves to new positions within the genome of a single cell. The mechanism of transposition can be either "copy and paste" or "cut and paste". Transposition can create phenotypically significant mutations and alter the cell's genome size

one in which the purine-pyrimidine orientation is changed to pyrimidine-purine or vice versa

1.     - a biological preparation that improves immunity to a particular disease. Typically contains an agent that resembles a disease-causing microorganism, and often made from weakened or killed forms of the microbe or its toxins. The agent stimulates the body's immune system to recognize the agent as foreign, destroy it, and "recognize" it, so that the immune system can more easily recognize and destroy any of these microorganisms that it later encounters. Vaccines can be prophylactic (e.g. to prevent or ameliorate the effects of a future infection by any natural or "wild" pathogen), or therapeutic

 properties that allow pathogens to survive, spread, and cause disease