Micro Part 1

7/31/2019 Micro Part 1

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Mary Rose H. GarciaBSMedTechFar Eastern University


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Significance Classification/ Taxonomy

Comparison of prokaryotic and eukaryotic

cell structure Bacterial morphology

Microbial growth and nutrition

Bacterial biochemistry and metabolism

Bacterial genetics


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Isolate,identify and analyze the bacteria thatcause diseases in humans

Knowledge of microbial structure and physiology(areas):

Culture of organisms from patient specimens

Classification and identification of organisms Prediction and interpretation of antimicrobial

susceptibility patterns

ecological niches-way in which organism uses its

resources habitats-organisms location and where its

resources may be found


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Understanding the growth requirements of a

particular bacterium-enables the to select the for and optimize the chance of the

.

Determination of staining characteristics (basedon different cell wall structure)-the

Metabolic biochemical differences b/worganisms-form the for

today.Cell structure and biochemical pathways of an

organism- determine its to various.


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-discovery of

beasties in a water droplet in hishomemade microscopeFather ofprotozoology and bacteriology

*Many of the microbes do not cause disease.

1. Bacteria

2. Parasites3. Fungi

4. Viruses


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Unicellular organisms Lack a nuclear membrane and true nucleus

Classified as [Gk. Kernel-

nucleus, pro-signifying before in time] No mitochondria, endoplasmic reticulum, or

Golgi bodies


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- unicellular organismsofmicroscopic size are multicellularorganisms

Protozoa-unicellular organisms within thekingdom Protista(obtain nutrition from

ingestion) Some are capable of locomotion (motile,

whereas others are nonmotile)

Categorized by :

*flagella- [Lt. whiplike]*pseudopodia- [Gk.false feet]

*cilia-[Lt. eyelash]


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> Many multicellular parasites may be as long

as .


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Heterotrophic eukaryotes (obtain nutrients

through absorption) Yeasts are a group of unicellular fungi that

reproduce asexually (no sex organ)

True yeasts do not form hyphae or mycelia

Most fungi are multicellular and many canproduce asexually or sexually.icellularorganisms

The bodies of multicellular fungi-composed

of filaments (hyphae) w/c interweave to formmats (mycelia)


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Moulds are filamentous forms that canreproduce asexually and sexually

Yeast and hyphae/mycelial forms growing asyeast at incubator or human temperature

Filamentous form at room temperature- fungi

are dimorphic Many dimorphic fungi produce systematic

diseases in human hosts


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Smallest infectious particles (virions)

Cannot be sen under an ordinary lightmicroscope

Neither prokaryotic nor eukaryotic

Many times, effects are seen on cell lines

(inclusions, rounding up of cells andsynctium) where these characteristics becomediagnostic for many viral diseases.

*synctium- cell fusion into multinucleated

infected forms)


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Characteristics that distinguish viruses fromliving things:

Consist of but ; theirmay be

)

(not composed of cells), lackcytoplasmic membranes, surrounded by a

that require

for inc. in number doesnot involve mitosis, meiosis or binary fission)and


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Obligate intracellular plants take over hostcell function to produce virus

(inc. in size) inviruses.

Viruses are mostly host and/or host cell

specificEx.1. HIV T helper cells (not muscle cells in

humans)


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2. Rabies virus dogs, skunks, bats, humans

Bacteriophage- virus that infects and possiblydestroys bacterial cells

[Gk. Phage-to eat]

Viruses are becoming better known by theirDNA or RNA makeup, host disease signs andsymptoms, chemical makeup, geographicdistribution, resistance to lipid solvents and

detergents, resistance to changes in pH andtemperature, and antigenicity (serologicmethods)


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Organization and type (either DNA or RNA), of

the viruss genome, how the virus replicatesand the viruss virion (virus outside of a cell)structureused to differentiate virus order,family and genera

* The Universal Virus Database of theInternational Committee on Taxonomy ofViruses-2000 description of viruses


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Taxonomy

the academic discipline of defining groups oforganisms on the basis of shared commoncharacteristics and giving names to those

group

[Gk. Taxes-arrangement; nomos-law]

Is the orderly classification and grouping oforganisms into (taxa) categories


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3 CATEGORIES OF TAXONOMY (based onsimilarities and differences in genotype andphenotype)

i. Classification/ Taxonomyii. Nomenclature

iii. Identification


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Genotype & Phenotype

*genotype-genetic make up of an organism orcombinations of forms of 1 or few genesunder scrutiny in an organisms genome

*phenotype- readily observable physical and

functional features of an organism expressedby its genotype


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Taxa-pl. of taxum

Formal levels of bacterial classification insuccessively smaller taxa or subsets:

(domain, kingdom, division (phylum in

kingdom Animalia), class, order, family, tribe,genus , species and subspecies)

Below subspecies level, designations(serotype or biotype) may be given to

organisms that share specific minorcharacteristics


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Protists (protozoans) of clinical importanceare named like animals, instead of divisions,one uses phyla (pl. of phylum) but the namesof others remain the same.

Bacteria are placed in domains Bacteria andArchaea,(include unicellular prokaryoticorganisms) separate from animals

Plants and protists are placed in domainEukarya


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Traditionally, diagnostic microbiologistsemphasize placement and naming of bacterial

species into 3 categories (ocassionally 4 or 5)1. family-sim. To human clan

2. Genus- human last name (pl.=Genera)

3. Species-human first name

*the proper word for species is an*order and tribe- for classification of plants and

animals; not always used for the classificationof bacteria

Eg. Staphylococcus(genus) aureus(species) epithetbelongs to the family Micrococcaceae

*there are usually different strains w/in a givenspecies of the same genus


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-provides naming assignments for eachorganism

Binomial System- every organism is assigned agenus and a species name

Family name-is capitalized and has an -aceaeending (e.g Micrococcacaceae)

Genus name-capitalized and followed byspecies epithet (begins with lowercase)

(e.g. Staphlococcus aureus/Staphylococcusaureus)

*often the genus name is abbreviated by usingthe first letter of the genus (capitalized)followed by a period and the species epithet

e.g. S. aureus


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To elimininate confusion, first two letters / thefirst two syllable-used when 2 or more generabegins w/ the same first letter

Species abbreviated sp.-singular/ spp. pluralspecies are not specified

When bacteria are referred to as a group- namesare neither capitalized nor underlined (e.g.staphylococci)

COMMON NAMES

* Gonococcus-Neissera gonorrhea*Pneumococcus-Streptococcus pneumoniae

*Tubercle bacilli- Mycobacteriumtuberculosis


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Process by w/c the microorganisms keyfeatures are delineated so that it can beassigned a genus and a species name

*genotyping

*phenotyping


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nucleus No nuclear membrane Membrane-bound

Chromosomal DNA In the nucleoid in the nucleus

Organelles absent Present

Cell wall peptidoglycan Polysaccharides

Pili and fimbriae present absent


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>bacteria vary in size fr. 0.4 to 2 m

>occur in 3 basic shapes: cocci,bacilli,spirochets

Cocci-sphericalBacilli-rod shaped

Spirochetes-spiralz

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Micro Part 1