Presentation is loading. Please wait.

Presentation is loading. Please wait.

BACTERIA.

Similar presentations


Presentation on theme: "BACTERIA."— Presentation transcript:

1 BACTERIA

2 Spherical Rod-shaped Spiral

3 Structure

4 Cell-Surface 1. Cell wall is made of peptidoglycan. 2. In Gram strain...

5

6 The lipid portions of the lipopolysaccharides in the walls of many gram-negative bacteria are toxic,causing fever or shock. Ther outer membrane of a gram-negative bacteria helps protect it from the body′s defenses. Some capsule protect against dehydration,and some prokaryotes from attacks by their host′s immune system. Frimbriae(singular,fimbria), pili(singular,pilus) and flagellum

7 DNA Because lack a membran-bounded nucleus,the chromosome is located in the nucleoid. In addition to its single chromosome,a typical prokaryotic cell have much smaller rings of independently replicating DNA molecules called plasmids.

8 Endospores When environments lack essential nutrient. Bacillus anthracis

9 Conjugation

10 Bacteria have both beneficial and harmful impacts on humans
Bacteria have both beneficial and harmful impacts on humans. Benefit : environment medical mutualistic Harm : diease

11 Actinobacteria (放線菌)---one example of bacteria
(1) Actinobacteria are a group of Gram-positive bacteria (2) Actinobacteria have high guanine and cytosine content in their DNA (3) terrestrial or aquatic (4) Actinobacteria are one of the dominant phyla of Bacteria

12 Characteristics of Actinobacteria
(1) Include some of the most common soil life, freshwater life, and marine life (2) Decomposition of organic materials, such as cellulose and chitin (3) Supply of nutrients an important part of humus formation

13 Actinobacteria --- bacteria or fungi??
fungi characteristics : 1. Some Actinobacteria form branching filaments,resemble the mycelia (絲狀體) of fungi 2. Some Actinobacteria species produce external spores. ---> Originally classified under the older name Actinomycetes bacteria characteristics : 1. Actinobacteria have no nuclear envelope 2. Cell wall is made of peptidoglycan

14 some of Actinobacteria can cause diseases
(1) Mycobacterium Mycobacterium tuberculosis cause Tuberculosis(肺結核) Mycobacterium leprae cause Leprosy(痲瘋病)

15 some of Actinobacteria can cause diseases
(2) Corynebacterium diphtheriae cause Diphtheria (白喉)

16 some of Actinobacteria can cause diseases
(3) Nocardia can cause Nocardiosis(諾卡氏菌病)

17 Some of Actinobacteria can produce antibiotics ---
There are more than 2000 kinds of antibiotics in the world,and almost 56% produce by Actinobacteria In 1942 Selman Waksman discovered that the soil bacteria he was studying made actinomycin(放線菌素) --->Streptomyces (鏈黴菌屬) (1) Streptomycin(鏈黴素) : Streptomyces griseus

18 some of Actinobacteria can cause diseases
(2) Oxytetracycline(土黴素) : Streptomyces rimosus (3) Gentamicin(慶大黴素) : Micromonospora(微單孢 菌屬)


Download ppt "BACTERIA."

Similar presentations


Ads by Google