BACTERIA

2 types of cell wall Gram negative -Thin layer of peptidoglycan Gram positive -Thick layer of peptidoglycan

Gram negative Bacteria with cell wall contain most Bacteria have 2 groups Nonphototrophic phototrophic -oxygen and anoxygenic

Nonphototrophic14 subgroup where 6 subgroups are pathogenSubgroups that are pathogenEnteric group facultative anaerobic short rods example: E.coli caused urinary tract infection and gastrointestinal illness 2. Campylobacter and Helicobacter Aerobic or microaerophilic motile example: Campylobacter jejuni caused diarrhea and Helicobacter pylori caused ulcer 3. Spirochetes morphology: slender and long with flexible and helical shape mechanism of motility: corkscrew movement caused syphilis and lyme disease 4. Chlamydias obligate intracellular parasite resemble virus: intracellular parasites and small size differ from virus: have both DNA nand RNA, plasma membrane, functioning ribosomes, metabolic pathway and reproduce by binary fission caused eye/genitourinary tract infection

Subgroup that are non pathogenic1. Pseudomonas, Azobacter, Rhizhobium Pseudomonas sp used to degrade complex organic molecules in soil Azobacter and Rhizobium used for Nitrogen fixation in soil.

PhototrophicAnoxygenic Photosynthesis under anaerobic condition H2S, Sulfur, H2 and organic matter as electron donor no chlorophyll but with bacteriochlorophyll do not release oxygen during photosynthesis habitat: deep inside ponds and lakes non pathogenic examples: Chromatium, Chlorobium and Rhodospirillium Chromatium violet/purple red internal sulfur granules purple sulfur bacteria Chlorobium green external sulfur granules green sulfur bacteria green sulfur bacteria Rhodobium red do not form sulfur granules purple non-sulfur bacteria

Oxygenic photosynthesis under aerobic condition water as electron donor with chlorophyll release oxygen during photosynthesis habitat: surface of ponds and lakes non pathogenic example: cyanobacteria (blue-green pigment)

Gram positive Bacteria with cell wallHave 6 groups 1. Gram positive cocci In pair,chain or cluster Example: Streptococcus pneumonia and Staphylococcus

2. Endospore forming gram positive Bacteria Rod-shaped Habitat: in soil Genus: Bacillus and ClostridiumBacillus Aerobes and facultative anaerobes Application: biological insecticides Examples: Bacillus sphaericus and Bacillus thuringiiensis Clostridium Obligate anaerobesClostridium botulinum caused botulism food borne pathogenexotoxin produced –neurotoxinflaccid paralysis –inhibition nerve excitationplastic surgeryClostridium tetani caused paralysis infect deep wounds potent neurotoxin spastic paralysis –inhibition nerve relaxation Clostridium perfringens gas gangrene, gas that clogs blood vessels

3. Regular nonspore forming gram positive Bacteria Rod-shapedExample: LactobacillusHomofermentative: produce lactic acid through Embden-pathwayHeterofermentative: produce lactic acid, ethanol and carbon dioxide through pentose phosphate pathway

4. Irregular nonspore forming gram positive Bacteria Club-shapedNapping binary fissionExample: Corynobacteriunm diphtherine

5. Mycobacteria Slightly curved to straight rodsAcid-fast stainSlow growerCell wall containing mycolic acidGrowth stimulated by lipid and fatty acidsExample: Mycobacteria tuberculosis

6. Actinomycetes Branching bacteriaSoil inhabitantAntibiotic producer –Chloromphenical, Erythromycin and TetracyclineExample: Streptomyces

Bacteria lacking cell wall MycoplasmaNo peptidoglycan and stained pink with Gram stainingDNA sequences similar to gram positive bacteria Irregular shapeProtoplast but resistant to osmotic lysisStrong plasma membrane –have sterol or lipoglycanRequire organic growth factors such as cholesterol, fatty acids, vitamin, amino acids and nucleotides/growth