Microbial-Diversity.pdf

Microbial diversity Microorganisms come all different shapes and sizes protozoa bacteria/archaea viruses fungi cyanobacteria/algae...

Microbial diversity Microorganisms come all different shapes and sizes protozoa bacteria/archaea viruses fungi cyanobacteria/algae diversity we see is as a result of 3.8 billion years of evolution Bacteria Bacteria most abundant group of “living” organisms on Earth (all metabolic diversities observed) relatively simple unicellular (chains, clusters) prokaryotic cell structure no organelle structure usually 1, circular chromosome (haploid), some contain plasmids DNA is not associated with histones genes contain no introns many bacteria swim (flagella) divide by binary fission, exponential growth characteristic ribosomes (70S) Bacteria several shapes reported  Bacteria several shapes reported individual bacteria may form pairs, chains, clusters Diplococci Tetrad Staphylococci Streptococci Coccus Sarcina (Neisseria) (Micrococcus) (Staphylococcus) (Streptococcus) Archaea Archaea live in extreme environments – 3 main groups 1. methanogens (strict anaerobes, produce methane) 2. extreme halophiles (salt loving) 3. extreme thermophiles (heat loving) predominantly chemoautotrophs share many properties with Bacteria unicellular, prokaryotes, no organelle structure divide by binary fission, usually 1, circular chromosome, genes contain no introns were originally classified with bacteria (Prokaryotes) Woese & Fox (1977) proposed that Archaea were distinct grouping Archaea ribosomes (70S) unique to the Archaea DNA associated with histones (eukaryotic-like) enclosed by a plasma membrane and rigid cell wall cell walls lack peptidoglycan - some have “S-layer” (proteins/glycoproteins, 5-25 nm thick, poorly conserved), - some have pseudopeptidoglycan (similar to peptidoglycan) membranes composed of branched hydrocarbon chains attached to glycerol by ether linkages (R-O-R) (different to bacteria) Fungi Fungi chemoheterotrophs degrade complex carbon chains (e.g. (lignin, cellulose) to produce energy typical eukaryotes features membrane bound organelles multiple linear chromosomes some haploid, some diploid genes contain introns & exons DNA associated with histones 80S ribosomes rigid cell wall containing chitin Unicellular Fungi bakers, brewers & fission yeast Candida albicans generally oval shaped yeast budding yeast can form spores much larger than bacteria (asexual) (sexual) buds form and pinch off of the parent cell Multicellular Fungi Form mycelia long branched filaments called vegetative hyphae Reproduction spores hyphal fragmentation sporangia gametangia asexual asexual sexual Dimorphic Fungi grow either unicellular (yeast) or as mycelium (mold) switch can be environmental stimulus Blastomyces dermatitidis survives in soil that infects mammals contains organic debris myceliu unicellular m Switch at 37oC triggers change to yeast-like form causes Blastomycosis Protozoa Protozoa predominantly chemoheterotrophs - “hunters” and “grazers” feed on other microbes free living (Paramecium, Amoeba) parasitic (Plasmodium, Trypanosoma, Giardia) unicellular typical eukaryotes features membrane bound organelles multiple linear, chromosomes DNA associated with histones eukaryotes genes contain introns & exons 80S ribosomes Protozoa lack cell walls They move by… pseudopodia flagella cilia Protozoa Asexual reproduction binary fission one cell splits into two schizogony nucleus divides many times before cell divides the single cell separates into daughter cells budding buds from and pinches off of the parent cell some protozoa reproduce sexually by fusion of gametes (e.g. Plasmodium) some produce cysts (Giardia, Entamoeba) Algae Algae Photoautotrophs oxygenic (produce oxygen via photosynthesis) photosynthetic machinery derived from cyanobacteria different pigmentation (red, green, brown) They are Eukaryotes and have… organelles multicellular unicellular (seaweeds) multiple linear chromosomes genes have intron & exon structure DNA associated with histones 80S ribosomes Cell walls contain cellulose BUT: they lack organs found in plants (roots, leaves)