Bacteria are generally simple structures. Bacterial cells
missing membrane core. Therefore, bacteria
described as prokaryotes,
to-value and to-nucleus from the Greek word for the kernel. Despite its simplicity, bacteria
is a huge range of metabolic capabilities, and can be found in some
the most extreme conditions on Earth. Only a small minority
bacteria cause disease. There are three basic shapes that bacterial cells adopt. They
or round, rod or spiral shape. Round bacteria called kokamy
(
singular: cocci) and rod
form of bacteria known as bacilli (
singular: bacillus). "Sticks" term
means bacilliform bacteria should not be confused with
genus of bacteria known as "Bacillus >> <<. Form
bacterial cells is of fundamental importance in the classification and identification of bacteria
. Although bacteria are divided into three main forms
they discover the amazing variety of forms, when viewed
microscope. Bacteria may be conveniently divided into two
additional groups based on their ability to retain crystal violet
-iodine dye complex when cells are treated with acetone or alcohol
. This reaction is called the gram reaction
named after Christian Gram, who developed the staining protocol
1884. This may seem very arbitrary basis on which its built
classification system. This reaction, however, shows a fundamental
differences in the structure of bacteria. Electron microscopy shows that
Gram-negative and gram-positive bacteria have fundamentally different structures
associated with the composition of the cell wall,
among other things. Flagellates are responsible for motility of pathogenic bacteria >> << and may play a role in producing disease. Gram-negative bacteria
pathogens can be put in a fine hair called
fimbriy (single: fringe) it helps to observe the surface of the body. Saws can connect two bacterial cells together: sex drunk required to transfer
certain plasmids between bacteria. Gram-negative bacteria have additional structures. They exchanged
genetic material in the process of communication, including cell be joined
sex drunk: tube-like structures through which DNA
passed. The surface of Gram-negative cells also seen in the manner
similar to the hair structure, called
fimbriy (some also microbiologists
call these blades, confusing them with sex drunk). They play an important role in adhesion >> << and may play a central role in virulence. If the microbe is
cause an infection in the first place should add to its surface. Some bacteria are enclosed in a capsule. This protects
, bacteria, even within phagocytes
helping to prevent cells from death. Encapsulated bacteria grow as a "smooth" colonies, while colonies of bacteria
who lost their capsules appear rough. Rough colonies do not usually cause disease. Encapsulated bacteria do
. not succumb to intracellular killing as easily as bacteria, have no capsule
Strains of Streptococcus
pnuemoniae, which lack capsule
do not cause disease. All bacteria that cause meningitis are
encapsulation. Suspension of bacteria in the ink is an easy way
showing capsule. Ink particles can not penetrate the capsule >> << Material and encapsulated cells appears to be an aura around them. This >>
<< a reaction capsule swelling reaction. In response to this "reaction swelling of capsules, bacterial cells in resuspendiruyut
serum, which has antibodies against the capsule. This causes >> << capsule swells, and it can be easily visualized
suspension in ink. Ink particles can not penetrate the capsule, which
This looks like a halo around the bacterial cells. Some bacteria produce slime to help them stay on the surface. Mucus is
production of several types of pathogenic microbes, and are usually composed of polysaccharides. Mucus production
mutans Streptococcus allows it
hold on the tooth strattera surface, where it helps form plaque, a leading
eventually to tooth decay. "Koahulazonehativnyh 'staphylococci live on the skin >> << and some strains form mucus, which allows them to adhere to plastic. These bacteria cause infections associated with implanted medical devices << plastic. >> A few species of bacteria have the ability to produce high resistance
structure, known as endospory (or simply spores). They confront some
dangerous environments and protection from exposure to heat, radiation and drying. Endospory form within (hence
endo-) special vegetative cells known as sporangia (sporangia only). Diseases caused by bacteria include sporonosni
botulism (Clostridium botulinum)
gas gangrene (Clostridium perfringens
),
tetanus (Clostridium tetanus) and acute food poisoning (Clostridium perfringens, again ) These bacteria are "anaerobic". Aerobic bacteria sporoobrazuyuschyy can also cause disease. Anthrax is caused by
anthrax bacillus. Bacillus Cereus causes two types
food poisoning. . << >>