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BACTERIA
Spherical
Rod-shaped
Spiral

Structure

Cell-Surface
1. Cell wall is made of peptidoglycan.
2. In Gram strain...
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

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.

Endospores
When environments lack essential nutrient.
Bacillus anthracis

Conjugation
Bacteria have both beneficial and harmful impacts
on humans.
Benefit : environment
medical
mutualistic
Harm : diease
 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

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
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


some of Actinobacteria can cause diseases
(1) Mycobacterium --Mycobacterium tuberculosis cause
Tuberculosis(肺結核)
Mycobacterium leprae cause
Leprosy(痲瘋病)

some of Actinobacteria can cause diseases
(2) Corynebacterium diphtheriae cause
Diphtheria (白喉)

some of Actinobacteria can cause diseases
(3) Nocardia can cause Nocardiosis(諾卡氏菌病)
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


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)