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Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R.

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Presentation on theme: "Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R."— Presentation transcript:

1 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings PowerPoint ® Lecture Slide Presentation prepared by Christine L. Case M I C R O B I O L O G Y a n i n t r o d u c t i o n ninth edition TORTORA  FUNKE  CASE Part A 12 The Eukaryotes: Fungi, Algae, Protozoa, and Helminths

2 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Eukaryotic  Cells contain a nucleus  Aerobic or facultatively anaerobic  Makes ATP (energy) through respiration if oxygen is present, but can go through fermentation if oxygen is not present  Chemoheterotrophic  Must break down and absorb organic compounds for energy and carbon  Most are decomposers Fungi

3 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Types of fungi: Molds  The thallus (body) of a mold consists of long filament of cells joined together called hyphae  Grow by elongating at the tips  Every part of a hypha (singular) is capable of growing  Most fungus grown in labs is grown from fragments  When conditions are favorable for growth, hyphae will grow into a mass called a mycelium Figure 12.2

4 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Types of Hypha  Vegetative hypha  The portion of a hypha that obtains nutrients  Aerial hypha  Portion of hypha concerned with reproduction  Projects above the surface the mold is growing on  Usually produce reproductive spores

5 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Types of Fungi: Yeasts  Nonfilamentous, unicellular fungi  Typically spherical or oval in shape  Two types:  Budding yeasts - divide unevenly  A protuberance known as a bud forms on the surface of a parent cell and elongates, eventually breaking off after the nucleus divides  Some yeast buds fails to detach and instead form a small chain of cells called a pseudohypha  Ex: Candida albicans attaches to human skin cells but require pseudohypha to get to deeper tissue Figure 12.3

6 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

7  Fission yeasts  Divide evenly to produce two new identical cells  Entire parent cell elongates and splits  Similar to bacterial fission

8 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Dimorphism - The ability to take on two different forms  Can grow as either yeasts or molds  Usually temperature dependent  histoplasma capsulatum below is yeast like at 37 C (left), but mold like below 36 C (right)  Can be dependent on presence or lack of CO2 Figure 12.4

9 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fungal life cycle  Fungi reproduce both sexually and asexually through the use of spores  Formed from aerial hyphae  Asexual spores are formed by hyphae of one organism  When they germinate, they produce genetically identical organisms to the parent

10 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Types of asexual spores  Conidiospore  Uni or multicellular spore that is not enclosed in a sac Sporangiospore – formed within a sac A single sac can contain hundreds of spores

11 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Sexual spores result from fusion of the nuclei from two strands of the same species  Results in organisms with characteristics of both parental strands  Three phases  Plasmogamy: nuclues of donor cell penetrates cytoplasm of recipient cell  Karyogamy: two nuclei fuse  Meiosis: nucleus divides to form spores

12 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings

13 The difference between bacteria and fungi  Fungi are adapted to environments that would be hostile to most bacteria  Grow better in environments that are too acidic for bacterial growth  Can grow in high sugar or salt concentrations  Can grow on substances with low moisture content  Require less nitrogen  Can metabolize complex carbs

14 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Fungi Phyla  The following three phyla are telemorphs  Can reproduce both sexually and asexually  Zygomycota  Conjugation fungi  Reproduction occurs when hypha of two fungi merge together to form spores instead of using a reproductive structure such as a mushroom cap  Have coenocytic hyphae  Multinuclear  Occurs when there is mitosis but not cytokinesis

15 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Zygomycete Life Cycle Figure 12.6 Zygospores are created when two fungal hypha fuse – sexual reproduction A sporangium will form from the zygospore which produces hundreds of identical spores to be released for new fungi to grow – asexual repro.

16 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Ascomycota  Sac fungi  Septated hyphae  The hypha have a cell wall-like septa within to make it look like it is multicellular  Some are anamorphs – have lost the ability to reproduce sexually

17 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Ascomycete Life Cycle Figure 12.7 Asexual repro: spores are usually conidia that are produced in long chains and can freely detach Sexual repro: ascopores result from the fusion of two nuclei Produced in the ascus (saclike structure)

18 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Basidiomycota  Club fungi  Septate hyphae  Include fungi that produces mushrooms

19 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Basidiomycete Life Cycle Figure 12.8 Asexual repro: portion of hypha breaks off and grows into a new hypha/mycelium Sexual repro: basidiospores are produced on the basidium In cap mushrooms, these are located on the gills

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21 Fungal diseases  Mycosis: any fungal infection  Generally chronic (long-lasting) because of the slow growth of fungi  Classified into 5 groups  Based on the degree of tissue involvement and mode of entry into host  Many are difficult to treat because of the close evolutionary relationship between fungal and animal cells

22 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Systemic mycoses  Fungal infections deep within the body  Can affect a number of tissues and organs  Not restricted to any one region of the body  Usually caused by fungi found in soil  Transmitted through inhalation of spores  Typically begin in the lungs and spread to other tissue  Not contagious  Ex: histoplasmosis(aka cave disease)

23 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings  Disseminated histoplasmosis: has spread beyond the lungs and is life threatening at this point

24 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Subcutaneous mycoses  Fungal infections beneath the skin  Caused by saprophytic fungi (decomposers – break down dead/decaying matter) that live in soil and on vegetation  Ex: sporotrichosis  Common in gardeners and farmers that causes lesions on the hands (or wherever comes in contact)  Infection occurs when spores or part of the mycelium enter a puncture wound on skin

25 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Cutaneous mycoses  Aka dermatomycoses  Infect the epidermis, hair and nails  Caused by dermatophytes  Secrete keratinase, an enzyme that breaks down keratin  Transmitted human to human or animal to human by direct contact with infected hair or epidermal cells  Ex: athlete’s foot and ringworm

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27 Superficial mycoses  Infections localized along hair shafts and in surface epidermal cells  Most prevalent in tropical climates  Very similar to cutaneous  Difference is the localization – does not spread around the body

28 Copyright © 2006 Pearson Education, Inc., publishing as Benjamin Cummings Opportunistic mycoses  Caused by normal microbes or fungi that typically are harmless  Become pathogenic in a host with a compromised immune system  Examples:  Pneumocystis - most common life-threatening infection in AIDS patients  Stachybotrys – normally grows on cellulose of dead plants, can cause fatal pulmonary hemorrhage in infants when found in homes


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