Micropara finals Flashcards
Viruses
What cell type are viruses
Acellular
Viruses lack what?
Metabolic machinery
Identify the type of virus by its basic morphology:
Capsomers, Nucleic acid, Capsid
Naked virus
Identify the type of virus by its basic morphology:
Envelope, Capsid, Nucleic acid
Enveloped virus
Identify the DNA Viruses:
Parvovirus, Papovavirus, adenovirus, Iridovirus
Nonenveloped
Identify the DNA Viruses:
Hepadnavirus, Poxvirus, Herpesvirus
Enveloped
Identify the DNA Viruses:
Picornavirus, Reovirus
Nonenveloped
Identify the DNA Viruses:
Togavirus, Rhabdovirus, Orthomyxovirus, Bunyavirus, Coronavirus, Arenavirus, Retrovirus, Paramyxovirus
Enveloped al ss RNA
Enumerate the Family, Subfamily, Genus, and Species of Virus
Family - viridae
Subfamily - virinae
Genus - virus
Species - virus
What are the Primary characteristics of a virus?
Chemical nature, structure, Site of replication
What are the Secondary characteristics of a virus?
Host range, mode of transmission, Specific surface structures
Identify the characteristic of a virus:
RNA or DNA (ss or ds); + or - strand; MW
Chemical nature
Identify the characteristic of a virus:
shape, no of capsomeres, diameter of nucleocapsids
Structure of virion
Identify the characteristic of a virus:
Nucleus or cytoplasm
Site of replication
Identify the characteristic of a virus:
Host species; specific host tissues or cell types
Host range
Identify the characteristic of a virus:
e.g feces
Mode of transmission
Identify the characteristic of a virus:
e.g. antigenic properties
Specific surface structures
What icosahedral Viruses have No envelope
Papovaviridae, Picornaviridae
What Icosahedral viruses are ds DNA?
Herpesviridae, Hepadnaviridae
What icosahedral viruses have nucleus as their assembly site?
Papovaviridae, Herpesviridae, Hepadnaviridae
What are the similarities of all Helical viruses?
All have envelope and all have an assembly site of cytoplasm
Viruses that infect bacteria
Bacteriophages
Identify the type of bacteriophages:
Destroy their host cells (by lysis)
Lytic/Virulent
Identify the type of bacteriophages:
Do not destroy host cells
Integrate viral nucleic acid to host-cell genome and replicate without any cell lysis (Lysogeny)
Carried out in phages containing ds DNA
Temperate phages/ Avirulent
Enumerate the stages of virus replication
- Attachment (Adsorption)
- Penetration (injection)
- Synthesis of nucleic acid and protein 4
- Assembly and packaging
- Release (lysis)
Enumerate the steps of attachment of T4 bacteriophage virion to the cell wall of Escherichia coli and injection of DNA
(a) Unattached virion.
(b) Attachment to the
wall by the long tail
fibers interacting
with core
polysaccharide.
(c) Contact of cell wall
by the tail pins.
(d) Contraction of the
tail sheath and
injection of the DNA
True or False:
Unlike bacteriophages, animal viruses the entire virion is taken up into the cell
True
The Virus avoids the host’s immune response by
Growing inside cells
Viruses access to host cells because they have ______________________________ on host cells
attachment sites for host cells
Visible signs of viral infections are called
Cytopathic effects (CPE)
Is the smallest known infectious agents. Occurs only in plants, Does not posses protein coat
Viroids
Proteinaceous infectious particles. An unconventional virus
Prions
The possibility proteins are coded for by a gene found the normal host DNA
Altered protein
Medical-microbiology
Is a condition in which individuals of species live in close association with individuals of another species
Symbiosis
Identify the way in which symbiotic organisms interacts:
Form of symbiosis in which each organism benefit
e.g. bacteria in gut that aid digestion in both humans and animals and in turn obtain food from the human body
Mutualism
Identify the way in which symbiotic organisms interacts:
One organism benefits while the other organism neither benefits nor suffers from the interaction
e.g. this bacteria on epithelial surfaces such as in skin and respiratory tract
Commensalism
Identify the way in which symbiotic organisms interacts:
One organism lives in or on the body of another organism and is dependent on the host for its survival
e.g. viruses, parasitic worms, bacteria that causes strep throat, bubonic plague bacteria, cholera bacteria, etc.
Parasitism
Identify the way in which symbiotic organisms interacts:
The inhibition of one species of organisms by another
antibiotic production by microorganisms; myxobacteria and streptomycetes secreting lytic enzymes that degrade cell walls of other bacteria
Antagonism
Identify the way in which symbiotic organisms interacts:
As supply of nutrients decreases, rapidly growing species deprive those that grow slowly of food
e.g. microorganisms growing in fermented fruits/vegetables
Competition
Identify the way in which symbiotic organisms interacts:
One organism, the predator, feeds on and digests another organism, the prey
e.g. protozoa feed upon bacteria and some algae, bbdelovibrio bacteria feed upon other bacteria
Predation
Identify the characteristics of normal flora organisms:
due to chemical receptors in the body cell
e.g. proteins, polysaccharides, pili
Adhere to host cells
The detachment of host epithelial cells from body surfaces and replacement of the host cells by new cells
- affects microbial adherence
Desquamation
Identify the characteristics of normal flora organisms:
Residents flora produce metabolic products that can inhibit other microbes
Production of antimicrobial substances
This is considered the first line of defense
Skin
Inhibitory substances in the skin include
Sweat, lysozyme, sebum
The upper respiratory tract compromises of what?
Mouth, teeth, gum
Part of the Upper Respiratory Tract that is abundant in moisture, high dissolve food and food particles, saliva (10^8 bacteria per ml)
Mouth
Part of the Upper Respiratory Tract that is anaerobic environment
-G+anae = S. mutans
Teeth
Part of the Upper Respiratory Tract that is fac. anae (S. sanguinis) to anae (Actinomyces)
G- Porphyromonas (gingivitis);
motile Treponema denticola &
Trichomonas tenax (gingivitis)
Gum
Has no normal flora due to cilia-driven flow of mucus
Lower Respiratory Tract
True or False:
Note that the plaque builds preferentially near
the gum line, first occurring directly adjacent to the mucous membranes of the
gingiva.
True
Part of the Gastrointestinal Tract that has numerous transient
- fluid < 10 bacteria per ml (due to HCl and digestive enzymes)
- Lactobacilli, Candida sp.
Stomach
Part of the Gastrointestinal Tract that has a few strong acid and bile
Small intestine
Part of the Gastrointestinal Tract that is the largest population in the human body
- 10 ^11 orgs/g wt of stool (25% feces)
- 300 diff bacterial species from feces
- 3x 10^13 daily thru defecation
Large intestine
Part of the Genitourinary that is free of microorganisms
Kidneys, ureters, urinary bladder
Part of the Genitourinary
G+ = Staph. epidermidis,
Strep.faecalis,
Corynebacterium
G- cocci – Neisseria sp.
G- fac anae rods = E. coli
Lower urethra
Part of the Genitourinary
lactobacilli, enterococci,
Corynebacterium,
Candida albicans, high
anae bacteria
Vagina
A predominant organism in the vagina of women between the onset of puberty and the end of menopause.
Lactobacillus acidophilus
A pathogen that initiates response in healthy individuals
Primary pathogen
Causes infections that develop in people with low resistance, prolonged antibiotic therapy and immunosupressive therapy
Opportunistic pathogen
The degree of the ability of a pathogen to cause disease
Virulence
The microbial properties that enhance a microorganism’s pathogenicity
Virulence factors
Streptococcus pnuemoniae
w/ capsule = _______
w/o capsule = _______
w/ capsule = virulent
w/o capsule = avirulent
Identify the virulence factor:
capsules – resist phagocytosis
Cellular factors
Identify the virulence factor:
poisonous substances
Toxin producing
Toxin released in medium
Exotoxins
Toxin retained in cell
Endotoxins
Identify the virulence factor:
affects invasiveness (penetration of tissues)
Hyaluronidase produced by Strep. pyogenes in oral cavity
and Staph. aureus in skin – allows them to destroy
mucosa, affects tissue hydration & decelerates healing
Extracellular enzymes
Excreted by Gram + &
Gram – bacteria
Proteins
Heat labile
Convertible to toxoids
Specific for a particular
type of cell function
High toxicity ( minute
amounts)
Eg. C. botulinum toxin
Exotoxin
Released by lysed cells of
Gram – bacteria
Lipopolysaccharide
Heat stable
Cannot form toxoids
Generalized effect (eg.
shock & fever)
Low toxicity (larger
amounts)
E.coli toxin
Endotoxin
Factors Affecting Pathogenicity:
1. Cellular factors
2. Toxin producing
3. Extracellular enzymes
Properties inherent to the microbe
Factors Affecting Pathogenicity:
Resistance vs susceptibility
Ability of the host to resist infection
Steps for a pathogen to accomplish in order to cause disease
- infect the host
- metabolize & multiply
in host tissue - resist host defenses for
a time - damage the host
Type of resistance factor that is not directed at any one specific pathogen
Non-specific resistance factors
Type of resistance factors where host develops defense mechanisms in response to a specific pathogen, or specific resistance against that pathogen
Specific resistance factors
Internal defense mechanisms
A. Cellular mediators
B. Soluble mediators
C. Inflammation
D. Fever
External defense mechanisms:
chemical secretions
Lysozyme, sebum, lactoferrin, transferrin
Internal defense mechanism:
Cellular mediator that is non-phagocytic but kills tumor and virus-infected cells by binding to a target cell and releasing membrane-destroying protease and phospholipase enzymes
Natural killer cells
Internal defense mechanism:
Cellular mediator
Leukocytes (WBC)
Granulocytes – neutrophils, Eosinophils,
Basophils
Agranulocytes – lymphocytes, monocytes
Phagocytic cells
Internal defense mechanism:
Soluble mediator that 20 interacting proteins
(antimicrobial peptides) in serum – - activated by
invading mcgs or by antibody binding; some act as
protease, some act on surrounding inflammatory cells
-produced by mucous membrane cells &
phagocytes
Complement
Internal defense mechanism:
Soluble mediator that is soluble proteins produced and secreted by sensitized T lymphocytes
Lymphokines
Internal defense mechanism:
Soluble mediator are small proteins produced by eukaryotic cells in response to viral infection or foreign dsRNA
Interferons
This causes:
loss of appetite
headache
raised body temperature
raised metabolic rate
Intensifies the effects of interferons, inhibits growth of
some microbes and speeds up body reactions that aid
repair
Fever
Not directed to a specific type of pathogen
Skin, normal microflora, antimicrobial chemical secretions of the body (HCL
in gastric juice, lysozyme, etc)
Non-specific immunity
Directed to a specific type of pathogen
Involves cells that specifically respond to antigens which are distinguished on the
basis of their surface markers.
Specific immunity
- mediated by antibodies (immunoglobulins); involves action of B cells
Humoral Immunity
Cellular reactions directly mediated by T cells or their factors
(lymphokines)
Cellular Immunity
Occur when people consume food
containing a toxin made by a microorganism
- also called Food intoxication
Food poisoning
caused by heat
stable enterotoxin of Staphylococcus spp
Staphyloccocal food poisoning
Caused by exotoxin-producing
bacteria (C. botulinum) acting on the central
nervous system causing respiratory failures
Botulism
Caused by
mycotoxin-producing fungi (eg. ergot by
Claviceps purpurea & aflatoxin by A. flavus,
Penicillium)
Mycotoxin Food poisoning
by Salmonella spp.;
abdominal pain, diarrhea
Salmonella gastroenteritis or Salmonellosis
by Salmonella typhi;
infection of bloodstream; high fever
Typhoid fever
by Campylobacter jejuni;
diarrhea in humans
Campylobacteriosis
by Vibrio cholera;
don’t invade intestinal wall & body tissues but causes severe
diarrhea
Cholera
by Yersinia enterocolitica
fever & severe abdominal pain, vomiting & diarrhea
Yersiniosis
by Vibrio parahaemolyticus;
from consumption of contaminated shellfish
hemolysin & showing symptoms of “explosive” watery diarrhea;
blood poisoning (Septicemia
Vibrio parahaemolyticus gastroenteritis & Septicemia
by E. coli;
from contaminated water, salads, raw vegetables
Traveller’s diarrhea
by “shiga” toxin-producing bacteria, Shigella,
causing diarrhea in patients w/ blood & mucus in stools
(bacillary dysentery)
Shigellosis
gastroenteritis –from raw meat & poultry
Clostridium perfingens
by Listeria monocytogenes;
bacteria live in macrophages, makes hemolysin & causes
stillbirth or meningitis in infants & adults.
Listeriosis
Clostridium perfingens um
1 um in diameter
Listeria monocytogenes um
0.5 um
by Trichinella (tiny worm)
flu-like but lasts for year or more
Trichinosis
by Giardia lamblia
fatigue, nausea, intestinal gas cramps, weight loss
Giardiasis
by Toxoplasma gondii (a protozoan)
can cause enlarged lymph nodes, sever muscle pain &
headaches & skin rash
Toxoplasmosis
by tiny roundworm Anisakia
tingling sensation in throat, vomiting up worms, abdominal
pain, nausea
Anisakiasis
Industrial Microbiology and Biotechnology
The study of industrial importance/uses of microorganisms
Industrial Microbiology
The use of living systems in technology
Biotechnology
Makes use of genetically engineered organisms for the
production of commercially important products or
improvement of processes.
Recombinant DNA Technology
Categories of Industrial Products
- Microbial cells
- Large molecules
- Primary metabolic products
- Secondary metabolic products
Cells are used to chemically convert a
specific substance from one form to another
Bioconversion
Essential features of an industrial microbiological process
Microorganism + Substrate -> Recovery and Purification of Product + Residue or Waste
Products of
Microbial Dissimilation
Alcohol & alcoholic beverages
Vinegar- by Acetobacter,
Gluconobacter
Lactic acid
Organic acids- citrate, gluconate, fumarate
Alcohol Fermentation by Saccharomyces cerevisiae
2 Pyruvic acid -> + 2 CO2 2 Acetaldehyde + 2NADH2 -> 2 Ethanol + 2NAD
Lactic Acid Fermentation
2 Pyruvic acid + 2NADH2 -> +2NAD
Bacterial enzymes
1.Streptokinase
2. DNA Polymerase/ Taq Polymerase
Fungal enzymes
- Lipase - rhizopus
- Cellulase - by Trichoderma reesii
- Glucose oxidase - aspergillus sp, penicillium
Identify the enzyme:
Streptococcus spp.
Treatment of patients following heart attacks
Streptokinase
Identify the enzyme:
Streptomyces spp.; Bacillus spp.
Production of high-fructose syrups
Glucose isomerase
Identify the enzyme:
Rhizopus spp.
Flavor improvement in processed food; improvement of cleaning action of detergents
Lipase
Identify the enzyme:
Trichoderma reesii
Digestive aid
Cellulase
Identify the enzyme:
Aspergiullus spp;
Penicillium spp.
Removes glucose from eggs prior to drying; removes oxygen from canned foods, soft drinks and beer; manufacture
Glucose oxidase
An enzyme is bound on a solid material such as paper, wood chips, ceramic and glass beads, or ion-exchange resins. Expanded greatly the commercial uses of microbial enzymes
Immobilized enzyme technology
Microbial synthesis amino acids
Glutamic acid by Corynebacterium glutamicum
Lysine – by mutant strain of C. glutamicum
Microbial Synthesis Pharmaceutical Products
Insulin – by genetically engineered E. coli
Interferons
Streptokinase
Interleukin
- Dextran –by Leuconostoc mesenteroides
- stabilizer in food products; blood plasma substitute - Xanthan gum- by Xanthomonas campestris
- Stabilizer & emulsifying agent in foods - Beta-carotene- by Blakeslea trispora
- Yellow coloring in foods - Vit. B12- Streptomyces olivaceus, Propioni freudenreichii
- treatment of pernicious anemia; food & animal feed
supplementation - Riboflavin - by Eremothecium ashbyi
- Vitamin supplement - Giberellic acid – by Fusarium moniliforme
- Growth hormone in plants
Application in Mining and Petroleum Industry, Bioremidiation and Agriculture
Microbial Biotechnology
Produce acids and oxidize ore w/ subsequent precipitation of metal
e.g. by Thiobacillus thiooxidans & Thiobacillus
ferooxidans
Leaching
Recovery of oils from wells mcgs produce acid to separate rocks, decrease viscosity
e.g. Psuedomonas putida - gen. Eng’d
Application in Petroleum Industry
The use of naturally occuring or genetically engineered biological agent (mcgs) to remove toxic pollutants from the environment
e.g Psuedomanas putida - gen. Eng’d
Bioremediation
Used as bioinsecticides
e.g Bt toxin by Bacillus thuringensis
B. larvae, B. popilliae
Production of transgenic plants using a binary vector
system in Agrobacterium tumefaciens
Application in Agriculture
Methods of gene transfer
Conjugation
Transformation
Transduction
Medical Parasitology
Focuses on parasites which cause disease in humans; also of great importance in veterinary medicine
Medical Parasitology
A very diverse set of eukaryotic pathogens
Parasites
Unicellular eukaryotes e.g. plasmodium
Protozoa
Multicellular organisms
Metazoa
flatworms these include flukes and tape worms
Platyhelminthes
Elongated round worms with rigid cuticula
Nematodes
Insects, ticks and mites which either are parasitic or
transmit parasites as vectors
Arthropods
live on, but not in
their hosts
Ectoparasites
live within the body
and tissues of their hosts.
Endoparasite
Most parasites are
obligate parasites
Ascaris 1.5 billion
Hookworms 1.3 billion
Whipworms 1 billion
Filarial worms 657 million
Malaria 500 million
Schistosomes 210 million
Amebiasis 50 million
Taenia tapeworms 50 million
Clonorchis 20 million
Chagas’ Disease 15 million
Parasites in the brain
Strongyloide, Ascaris, Toxoplasma, Echinostoma revolutum
Parasites in the eyes and lungs
Trichinella, Loa loa, Toxoplasma, Dirofilaria, Paragonimus, Ascaris
Parasites in the chest and liver
Dirofilaria - loa loa
Clonorchis
Fasciola
Parasites in the intestine
Fasciolopsis, Giardia, Entamoeba, Ascaris Tapreworm, Ancylostoma, Trichinella
Are caused by
transmittable parasitic agents including
bacteria, viruses, fungi, protozoa and a
variety of metazoans commonly referred
to as helminths or worms
Infectious diseases
Usually implies replication of
the agent resulting in a growing number
of pathogens
Infection
Are characterized by a
constant number of pathogens. Severity
of disease often depends on infection
dose.
Infestation
Is by definition the one in
which the parasite reproduces sexually
Definitive host
Additional hosts are then designated
Intermediate hosts
Host which actively transmit parasites to humans
are often called
Vectors
In _____ or transport hosts no parasite
development occurs
paratenic
Are alternate animal host from
which the parasite can be transmitted to humans
(zoonosis) or domestic animals
Reservoir host
Single host (no vector or intermediate host)
Direct Life Cycle
Requires a vector or an intermediate host of another species
Indirect lifecycle
Passive entry
Feeding drinking, direct contact, congenital transmission, transfussions
Active entry
Direct skin penetration by a specialized form of the parasite
By using a vector
First animal
Protozoan
Vegetative state which feeds upon bacteria and particulate nutrients
Protozoa Trophozoite
Some protozoa produce a protective capsule under adverse conditions
Protozoa Cyst
Protozoal cells without mitochondria
Archaezoa
Cells without mitochondria and microtubules
Microsporidia
Protozoa exhibiting amoeboid movement with the help of indefinite number of pseudopodia
Rhizopoda
Protozoa have an apical complex of some special organelles known as sporozoa
Apicomplexan
Cells with numerous cilia
Ciliophora
This phylum includes two different groups of flagellated protozoa
Euglenozoa
World-wide distribution, lives in the small intestine and
results in malabsorption
Giardia lamblia
May invade the colon and cause bloody diarrhoea –
amoebic dysentery. Also causes amoebic liver abscess
Entamoeba histolytica
More prevalent in the immunocompromised
Cryptosporidium parvum
Parasitizes the small intestinal mucosa and may
cause diarrhoea for several weeks
Cyclospora cyatenensis
A large motile ciliated parasite that lives in the colon of
pigs, humans and rodents and can lead to colonic ulceration
Balantidium coli
The cause of malaria. There are 4 species
that infect man: P. falciparum, P. vivax, P. ovale and P.
malariae
Plasmodium
Transmitted by the ingestion of
oocysts from cat faeces. Infection can lead to ocular
problems and is also a cause of neonatal toxoplasmosis
Toxoplasma gondi
Transmitted by sand flies, can lead to
visceral, cutaneous and mucocutaneous leishmaniasis
Leishmania
Haemoflagellates cause
Trypanosoma
Multicellular
Kingdom: Metazoa
Bilaterally Symmetric animals
Helminthes
Dorsal ventral flattening & a definite head end – most obvious
feature
Bilateral symmetry
Unsegmented body, 3 germ layers
No circulatory & respiratory systems, no skeleton, but with
excretory system
Platyhelminths (flat worms)
Taenia (tapeworm),
Echinococcus, Diphylobotrium
Tape-like (Class Cestoda)
Fasciola (liverfluke),
Schistosoma, Chlonorcis, Paragonimus
Leaf-like (Class Trematoda)
Acquired by ingestion of
contaminated, uncooked beef
Taenia saginata
Acquired by ingestion of
contaminated, uncooked pork
that contains cystercerci
Taenia solium
A common parasite
of humans and pigs in South- east Asia.
This parasite is one of the largest
trematodes to infect man (8cm in length)
and lives in the upper intestine. Chronic
infection leads to inflammation,
ulceration and haemorrhage of the small
intestine
Fasciolopsis buski
Widespread in the Far East and South east
Asia, the parasite is acquired by ingestion of
infective metacercariae in raw or pickled
crustaceans
Paragonimus westermani ( lung fluke)
A parasite of sheep, humans become
infected when ingest metacercariae
that have encysted on watercress.
The adult trematode lives in the
intra-hepatic bile ducts of the liver.
______” can lead to severe
anaemia in humans
Fasciola Hepatica
Widespread in China, Japan, Korea
and Taiwan, this parasite is
acquired by ingestion of infective
metacercariae in raw or pickled fish
Clonorchis sinensis
Vermiform or cylindrical, unsegmented body
Bilateral symmetry
Complete digestive system but lack circulatory & respiratory
systems
Sexual reproduction
Mostly dioecious (separate sexes), some are hermaphroditic
Examples: Ascaris, Dracunculus, Encylostoma, Enterobius, Filaria,
Strongyloides,Trichinella
NEMATHELMINTHS/NEMATODES
(ROUND WORMS)
A soil transmitted helminth
prevalent in warm, humid conditions
Can cause diarrhoea, rectal prolapse and
anaemia in heavily-infected people
Trichuris (whipworm)
A major cause of anaemia in the tropics
Ancylostoma and Necator (hookworms)
inhabits the small bowel
infection more severe in
immunospressed people (e.g.
HIV/AIDS, malnutrition, intercurrent
disease)
Strongyloides
Found world-wide in conditions
of poor hygiene, transmitted by
the faecal- oral route
Adult worms lives in the small
intestine
Causes eosinophilia
Ascaris (roundworm)
prevalent in cold and temperate
climates but rare in the tropics
found mainly in children
Enterobius (pinworm or
threadworm)
Transmitted by the simulium black fly,
this microfilarial parasite can cause
visual impairment, blindness and severe
itching of the skin in those infected
Onchocerca volvulus
FILARIA WORM
The major causative agent of lymphatic
filariasis
Wuchereria bancrofti
Another microfilarial parasite that causes
lymphatic filariasis
Brugia malayi
A world-wide infection of
dogs and cats
Human infection occurs
when embryonated eggs
are ingested from dog or
cat faeces
It is common in children
and can cause visceral
larva migrans (VLM)
Toxocara
Can be defined as the study of disease
Epidemiology
Is an infectious disease that can be transmitted from one person to another
Communicable disease
Is a communicable disease that is easily transmitted from person-to-person
Contagious disease
Is one that humans acquire from animal sources
Zoonotic disease
___ of a particular disease is the number of new cases of that disease in a defined populating during a specific time period
Incidence
Is the number of new cases of a particular disease that occurred during a specified time period per a specifically defined population
Morbidity rate
Is the number of cases of the disease existing in a given population during a specific time period
Period prevalence
Is the number of cases of the disease existing in a given population at a particular moment in time
Point Prevalence
Is the ratio of the number of people who died of a particular disease during a specified time period per a specified population
Mortality rate
