Micro exam 4

Fungi mycology

Chemoheterotrophic- (absorbs food), cell walls contain chitin, lack chlorophyll aerobic or facultative anaerobic

Molds- multicellular - Yeasts- unicellular

Eukaryotic reproduction

DNA packaged as chromosomes in the nucleus

Algae Fungi and some protozoa. reproduce asexually and sexually

Consists of Nuclear and cytoplasmic division

Nuclear division

-Has one or two complete copies of genome

single copy- (haploid)

Two Copies (Diploid)

Cytoplasmic Division

-Cytokinesis

Schizogony

-Produce multinucleate schizont

-after cytokinesis = many daughter cells

Significance of Fungi

-Decompose dead organisms and recycle their nutrients

-help plants absorb water and minerals

-used for food and in manufacture of foods and beverages

-produce antibiotics / serve as important research tools

-can spoil pickles, jelly, and fruit

Fungal morphology

Mold- long filamentous tube can either be septate or aseptate

Yeasts- small globular spore

Mycelium

Intertwined hyphae forms tangled mass

-can spread thousands of acres and go several feet deep

-mushrooms are the vsible portion of mycelium

Dimorphic

-change shape in response to environmental conditions

Spore form

-Disease causing form

Yeasts

-Unicellular fungi

-Fission yeasts

• divide symmetrically

• Binary fission

-Budding yeast

• divide asymmetrically

• Budding

-Pseudohyphae is short chins that form when buds don’t completely separate

asexual spores of molds

-Sporangiospore - spores that form inside a sac

-conidiospores - produced at tips or sides og hyphae

-Arthocondia - formed by the fragmentation of hyphae

Blastocondia-formed by budding yeast cells

sexual reproduction (3 phases)

Plasmogamy- (+ )Haploid donor cell nucleus penetrates cytoplasm of recipient cell (-)

Karyogamy - (+) and ( - ) nuclei fuse

Meiosis - Diploid nucleus produces haploid nuclei

Sexual spores

Zygomycota: fusion of haploid cells produces one zygospore

-Fusion of hypha (+) and Hypha (-)

Ascomycota: Sac fungi

-septic hyphae, reproduces sexuallly by acospores in ascus sac

Basidiomycota: formed Externally on a pedestal (basidium)

Fungal divisions Zygomycota

-conjugation fungi

-Sexual repro by Zygospores Asexual repro by Sporangiospores

Genera

-Rhizopus -Black bread mold

Fungal Divisions Ascomycota

-Sac fungi

-Sexual repro by ascospores, Asexual Repro by conidiospores on condia

-Genera

Aspergillus - opportunistic, systemic mycosis

Basidiomycota

-Club fungi

-Septate fungi, sexual repro by basidiospores on basidium pedestal, Asexual Repro by Fragmentation

-important decomposer of lignin - puts nutrients back into soil

-SHROOMIES

Genera-

Cryptococcus neoformans - Systemic mycosis

Anamorphs / deuteromycota

-Produce asexual spores only

-septate hyphae

-asexual reproduction by conidiospores

Genera- Penicillium

Economic effects of Fungi

-Saccharomyces: bread wine HBV vaccine

-Trichoderma: cellulase starch in plants

fungal diseases (mycoses)

Systemic Mycoses- deep within body

Subcutaneous Mycoses: beneath the skin

Cutaneous Mycoses: Affect hair skin and nails

Superficial Mycoses: Localized like hair shafts

Opportunistic Mycoses: caused by normal microbiota or environmental fungi

Algae

-Photoautotrophs

-Food through diffusion

-Vegetative structures

• Thallus, holdfasts

• stipes,blades

Divisions by:

-pigments, cell wall types, food storage polymers

Brown algae (Phaeophyta)

-cellulose,alginic acid and cell walls

-chlorophyll A and C

-store carbs, harvested for algin-food thickener.

Red algea

-chlorophyll A and D phycobiliproteins

-store glucose polymer, harvested for agar

Green algae

-Cellulose cell walls

-Chlorophyll A and B store glucose polymer

store glucose polymer, gave rise to plants td

Protozoa characteristics

-eukaryotic, unicelular, lack cell wall

-food by ingestion and absorption

-Motile by cilia, flagella, and or pseudopodia

-vegetative form a trophozoite

-Asexual reproduction is by fission,budding or schizogony- sexual by conjugation

-produce cysts (like endospore)

Distribution of protozoans

-Require moist environments

-most live in ponds lakes, some like in moist like beach sand or decaying matter.

Morphology-

2 nuclei, Macro and Micro nucleuses

-contractile vacuoles

(Phyla of protozoans) - Parabasala

-Lack mitochondria

-single nucleus

-Parabasala body- golgi body structure

—Trichonympha- found in gut of termites with digestion

(Phyla of protozoans) - Diplomonadida

-Lack mitochondria, golgi bodies, peroxisomes

-Contain 2 equal sized nuclei

-Multiple flagella

Giardi lamblia

Euglenozoa

-unicellular, rigid cell membrane, no cell wall

move by flagella with crystalline rod

-photoautotrophs, chloroplasts contain chlorophyll

-reproduce by mitosis, ad form cysts

Kinetoplastids:

Trypanosoma brucei

-african sleeping sickness - Tsetse Fly

Vector bite = lesion = necrotic tissue

Alveolates-cilliates

-move by cilia

-chemoheterotrophs

• vorticella- whirlpool current w cillia

• Didinium-phagocytize other protozoa

• Balantidium coli- pathogenic to humans

Amebozoa

-lobe shaped pseudopodia, and lack shells

-Free living- Naegleria Fowleri

Animal parasites- Entamoeba histolytica

Helminths flatworms and roundworms

-Eukaryote, multicellular

Chemoheterotrophic

-Parasitic lifestyles may lack digestive system, have reduced nervous system, and reduced locomotioon

-Reproductive lifestyle

• Egg→ Larvae→ Adult

Mono vs Dio -Ecious (Helminths)

-Monoecious -Both Male and Female reproductive systems in one animal

-Dioecious - separet male and female

(parasitic worms)

Kingdom: Animalia

-Platyhelminthes (flatworms)

• Trematodes (flukes)

• Cestodes (tapeworms)

-Nematoda (roundworms)

Trematodes (flukes)

-Food by oral sucker or absorption by outer layer

Clonorchis sinensis - (asian liver fluke)

Cestodes (tapeworms)

-Scolex- head

-Proglottids- segmented body

-Monoecious

-Taenia Saginata - Beef tapeworm

Nematodes (Roundworms)

-Diecious

-Some infect humans as eggs

-Enterobius - pinworm

Arthropods as vectors

-insect that carries and transmit diseases (vector)

Kingdom: Animalia - Phylum: arthropoda

classes:

• Insecta-6 legs Lice fleas and insects

• Arachnida- 8 legs-mites and ticks

Symbiosis

-The relationship between normal microbiota and the host

-some normal microbiotas are opportunistic which means an organism that wouldn’t normally cause harm eventually does cause disease like an overgrowth-they take an opportunity

Types of symbiosis

Commensalism - one benefit’s and one is unaffected

Mutualism - both benefit

Parasitism - one benefits at the expense of the other

Normal microbiota and the host

Resident microbiota - permanently colonize the host but do not produce disease under normal circumstances

Microbial antagonism: competition between microbes

Transient microbiota - present but only temporarily

Acquisition of normal microbiota

-Development in womb free of microorganisms (axenic)

-microbiotas begin to develop during birthing process

-much of one’s resident microbiota established during first months of life

Resivoirs of infections

-Site where pathogens are maintained as a source of infection

-Most pathogens cannot survive for long outside their host

-three types of reservoirs

• Animal

• Human

• Nonliving

Animal reservoirs

Zoonoses- diseases that naturally spread from animal to human

can acquire

-them through direct contact with animal or its waste

-eating animals

-bloodsucking arthropods

Human carriers

-Infected individuals who are asymptomatic but infective to others (latent disease)

-transmit from person to person - AIDS, gonorrhea

Non living reservoirs

-Soil water and food can be reservoirs of infection

-Prescence often due to contamination by feces or urine

-Botulism, tetanus, cholera

Exposure to microbes

Contamination- the mere presence of microbes on or in the body

Infection- colonization or invasion of the body by pathogen

Pathology - the study of disease

Etiology - the study of the CAUSE of a disease

Pathogenesis - The development of a disease

Portal of entry

Major pathways

Skin - they enter through natural openings, Hair follicles, sweat glands + Hookworm Larvae

Mucous membranes - Respiratory tract, by inhaling droplets or dust particles containing microbe + common cold, tuberculosis

Placenta - pathogens may cross the placenta and infect fetus

• spontaneous abortion, birth defect, premature birth

-Parenteral route - Deposition of microbes directly into tissues beneath skin or mucus membrane

• punctures, injections, bites, cuts, surgery

Portals and numbers of microbes

-Not all microbes cause disease - depends on portal of entry

• Streptococcus -pneumonia when inhaled (not through skin)

Numbers of invading microbes

-virulence or potency of toxins expressed as

• LD50 - (lethal dose) causes death in 50 % of test population

• ID50- (infectious dose) for 50% of test population

Role of adhesion in infection

-most pathogens have a method to attach to host cells

• necesary step in pathogenicty

• attaches by binding surface molecules to complimentary surface molecules on host tissues

Receptors - host cells surface molecules

Adhesions/Ligands - pathogens surface molecules

-Glycocalyx

The Nature of infections diseases

Symptom - a change in body function from a patient as a result of disease

-headache

Sign - a change in a body that can be seen measured or observed as a result of disease

-vomiting

Syndrome - a specific group of signs and symptoms that accompany a disease

Causation of Disease

-Germ theory of disease

Kochs postulates

Virulence factors and Infectious agents

Pathogenicity - ability of microorganism to cause disease

Virulence - degree of pathogenicity

Virulence factors contribute to virulence

• Adhesion factors

• Biofilms

• Extracellular enzymes

Enzymes and Increased virulence

-Some enzymes (exoenzymes) produced by bacteria and ejected from the cell can aid virulence

-Leukocidins destroy neutrophils and leukocytes active in phagocytosis

-Hemolysins cause lysis of erythrocytes

Coagulase / Kinases

Coagulase: coagulates fibrinogen

• clotting protect bacteria from phagocytosis

Kinases: Digest fibrin and breakdown clots

-releases the clot

More “ase”

Hyaluronidase: hydrolysed hyaluronic acid

Collagenase: hydrolyses collagen

Lecithinase: destroys plasma membrane

Protease- break down proteins

Toxins

-poisonous substances produced by some microorganisms

• toxemia - toxins in the bloodstream

Exotoxins: produced inside bacterium and then released into surrounding medium

Endotoxins: are part of the outer portion of the cell wall of G- bacteria released when killed -Lipid A Shock and fever

Effects of endotoxins

Response of endotoxin-shill, fever, weakness, generalized aches

Shock -life threatening loss of blood pressure

called septic shock when caused by G- organism ]

Pyrogenic response - causes fever

Antiphagocytic factors

Prevent phagocytosis

Bacterial capsule- slippery, foreign chemicals causes capsule to be camouflage

Antiphagocytic chemicals- prevent fusions of lysozyme and phagocytic vesicles

Leukocidins directly destroy phagocytic white blood cells

Plasmids / lysogeny

-virulence factors can be carried on plasmids or lysogenic phages

-plasmid encoded

-phage encoded

Pathogenic properties of fungi

Pathogenic properties of protozoa

pathogenic properties of helminths

pathogenic properties of algae

Stages of infectious disease

Incubation period -

prodromal period -

illness -

convalescence -

Transmission of diease

Direct - close association between infected and a susceptible host

Indirect by fomites - like doorknob, blanket

Vehicle - by inanimate reservoir like food, water

Vector - animals that carry vectors

• mechanical arthropod arries pathogen on feet (roach walkin on toothbrush)

• Biological - pathogens reproduce in vector

How are diseases classified

• the body system they affect

• longevity and severity

• how the disease is spread

• effect they have on population

classifying

communicable disease - disease that is spread from on host to another

Non communicable -

occurance of a disease

incidence - fraction of population that contracts a disease during a specific time

prevalence - fraction of a population having specific disease at a given time

sporadic - disease occurs occasionally

endemic

epidemic

pandemic

Emerging infectious diseases

New or changing disease showning an increased incidence in the recent past or a potential to increase in the near future.

Contributing factors to emerging

genetic recombination

evolution of new strains

inappropriate use of antibiotics and pesticides

changes in weather patterns

Extent of host involvement

Local infection: pathogen are limited to a small area of the body

Systemic infection: aninfection throughout the whole body

• bactermia

• septecimia

• toximia

• viremia

focal infection - started locally but now systemic

classification of infection

Primary infection -

Secondary infection -

Subclinical disease -

Predisposing factors

-Make the body more susceptible to disease

• short urethra in females

• inherited traits

• climate and weather

• age

• lifestyle

Types of nosocomial infections

-means hospital acquired infections

Exogenous - pathogen acquired from health care environment

Endogenous - pathogens arise from normal microbiota

Latrogenic -

Control of Nosocomial infections

• good aseptic technique

• isolation

• use of disposable or carefully sterilized equipment

• monitoring procedures to trace causes