Microbial diversity: Protists and Fungi

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Microbial diversity: Protists and Fungi by Mind Map: Microbial diversity:  Protists and Fungi

1. The Protists

1.1. Introduction

1.1.1. Eukaryotes with the taxonomic classification in flux

1.1.2. is artificial grouping of over 64,000 different single celled life forms

1.1.3. A polyphyletic collection of organisms

1.1.4. Most are unicellular

1.1.5. Lack the level of tissue organization present in higher eukaryotes

1.1.6. Distribution grow in a wide variety of moist habitats most are free living chemoorganotrophic forms play role in recycling nitrogen and phosphorus terrestrial and planktonic forms parasitic forms cause disease in humans and domesticated animals

1.2. Morphology

1.2.1. Plasma membrane structure similar to multicellular plants/animals

1.2.2. Cytoplasm sometimes subdivided into Outer gelatinous ectoplasm just underneath plasma membrane Inner fluid region termed endoplasm

1.2.3. Pellicle structure provides support

1.3. Taxonomy

1.3.1. Difficult to define due to vast differences in protists

1.3.2. Very much in flux and an area of active research

1.3.3. New classification scheme is based on that of the International Society of Protistologists doesn’t utilize hierarchical ranks (class and order)

1.4. Super-group

1.4.1. Excavata Includes some of most primitive, or deeply branching eukaryotes most have a cytostome Clades Fornicata Parabasilia Euglenozoa

1.4.2. Amoebozoa Amoeboid motility use of pseudopodia for locomotion and feeding Naked amoebae are surrounded only by a plasma membrane Testate amoebae plasma membrane covered by material made by amoeba or obtained from the environment Reproduce by binary or multiple fission

1.4.3. Rhizaria Amoeboid in morphology distinguished by fine pseudopodia (filopodia) axopodia Clades Stramenopila Alveolata

1.4.4. Archaeplastida Includes organisms containing a photosynthetic plastid that arose through an ancient endosymbiosis with a cyanobacterium all higher plants and many algal species are included

2. The Fungi (Eumycota)

2.1. Introduction

2.1.1. Eukaryotic, spore bearing

2.1.2. Chemoorganoheterotrophs with absorptive metabolism

2.1.3. Saprophytes absorb nutrients from dead organic material by releasing degradative enzymes osmotrophy - absorb soluble products

2.1.4. Lack chlorophyll

2.1.5. Reproduce sexually and asexually

2.1.6. 90,000 fungal species have been described, possible 1.5 million

2.2. Terminology

2.2.1. Mycology - study of fungi

2.2.2. Mycologists - scientists who study fungi

2.2.3. Mycoses - diseases caused by fungi

2.2.4. Mycotoxicology - study of fungal toxins and their effects

2.3. Taxonomy

2.3.1. Major fungal groups Chytridiomycota Simplest fungi, also called chytrids Produce a zoospore with single, posterior, whiplash flagellum Asexual and sexual reproduction Many members degrade cellulose and keratin Zygomycota Zygomycetes Most are saprophytes Form coenocytic hyphae containing numerous haploid nuclei Some of industrial importance Usually reproduce asexually by spores that develop at the tips of aerial hyphae Sexual reproduction occurs when environmental conditions are not favorable Genus Glomeromycota Aseptate flat hyphae ( appressoria ) to penetrate host plants; produce large, multinucleate spores and only reproduce asexually Major importance as mycorrhizal symbionts of vascular plants Ascomycota Introduction Genus More Pathogenic Ascomycota Basidiomycota Introduction Impact on Human Beings Urediniomycetes and Ustilaginomycetes Microsporidia Introduction Pathogenesis

2.3.2. Basidiomycota and Ascomycota are dikarya two parental nuclei are initially paired nuclei fuse, undergo meiosis, produce haploid progeny

2.3.3. Zygomycota and Chytridiomycota are paraphyletic taxonomic group includes some descendants of a single common ancestor

2.4. Distribution and Importance

2.4.1. Distribution Primarily terrestrial, few aquatic global from polar to tropical Some form associations mycorrhizae lichens Primarily terrestrial few aquatic species Many are pathogenic in plants or animals Decomposers degrade complex organic material in the environment to simple organic compounds and inorganic molecules carbon, nitrogen, phosphorus, and other critical constituents are recycled for other living organisms

2.4.2. Importance Industrial importance fermentation organic acids certain drugs antibiotics immunosuppressive agents Research use geneticists, cytologists, biochemists, biophysicists, and microbiologists Saccharomyces cerevisiae

2.5. General characteristics

2.5.1. Unicellular - few species

2.5.2. Multicellular - Mostly

2.5.3. Hyphae: Coenocytic (not divided into separate cells) and Septate (cells separated by septa)

2.5.4. Mycelium: large collection network of hyphae

2.5.5. Cell walls made of chitin