Blue-green bacteria

bacterium /bac·te·ri·um/ (bak-tēr´e-um) pl. bacte´ria [L.] in general, any of the unicellular prokaryotic microorganisms that commonly multiply by cell division, lack a nucleus or membrane-bound organelles, and possess a cell wall; they may be aerobic or anaerobic, motile or nonmotile, free-living, saprophytic, parasitic, or pathogenic.bacter´ial

acid-fast bacterium one not readily decolorized by acids after staining.

coliform bacterium one of the facultative, gram-negative, rod-shaped bacteria that are normal inhabitants of the intestinal tract; see Escherichia, Klebsiella, and Serratia.

coryneform bacteria a group of bacteria that are morphologically similiar to organisms of the genus Corynebacterium.

gram-negative bacterium see gram-negative, under G.

gram-positive bacterium see gram-positive, under G.

hemophilic bacterium one that has a nutritional affinity for constituents of fresh blood or whose growth is stimulated by blood-enriched media.

lysogenic bacterium a bacterial cell that harbors in its genome the genetic material (prophage) of a temperate bacteriophage and thus reproduces the bacteriophage in cell division; occasionally the prophage develops into the mature form, replicates, lyses the bacterial cell, and is free to infect other cells.

bac·te·ri·um (b

k-tîr

n. pl. bac·te·ri·a (-tîr

)

Any of the unicellular, prokaryotic microorganisms of the class Schizomycetes, which vary in terms of morphology, oxygen and nutritional requirements, and motility, and may be free-living, saprophytic, or pathogenic, the latter causing disease in plants or animals.

Bacterium

A microscopic one-celled organism. Haemophilus influenzae is a specific bacterium.

Mentioned in: Cat-Scratch Disease, Hemophilus Infections

bacterium.

See bacteria.

bacterium [bak-te´re-um] (pl. bacte´ria) (L.)

any prokaryotic organism. adj., adj bacte´rial.

Bacteria are single-celled microorganisms that differ from all other organisms (the eukaryotes) in lacking a true nucleus and organelles such as mitochondria, chloroplasts, and lysosomes. Their genetic material consists of a single loop of double-stranded DNA, whereas the genetic material of eukaryotes consists of multiple chromosomes, which are complex structures of DNA and protein.

Bacteria reproduce by cell division about every 20 minutes, giving them a very high rate of population growth and evolution. Genetic material can be transferred between bacteria by three processes: transformation (absorption of naked DNA), transduction (transfer by a virus), and conjugation (transfer by independently replicating DNA molecules, called plasmids, which can be inserted into the bacterial DNA). Some bacteria can also form spores, dehydrated forms that are relatively resistant to heat, cold, lack of water, toxic chemicals, and radiation.

Most bacteria have a rigid cell wall outside of the cell membrane primarily composed of a dense layer of peptidoglycan, a network of polysaccharide chains with polypeptide crosslinks. Some antimicrobials, the penicillins and cephalosporins, act by interfering with peptidoglycan synthesis.

Bacteria can have any of three types of external structures: flagella (whiplike locomotor organelles), pili (minute filamentous appendages), or a capsule (a layer of gelatinous material around the cell). Various types of pili are involved in conjugation and in the adherence of bacteria to mucosal surfaces. The capsule protects the bacterium from phagocytosis.

Bacterial structure and morphology. From Hart and Shears, 1997.

Classification of Bacteria. Bacteria are classified into two major groups, gram-positive and gram-negative, based on their reaction to Gram stain. Other important classification characteristics are morphology and metabolic reactions. A spherical bacterium is called a coccus. Some species do not always completely separate when the cells divide and characteristically occur in pairs (see diplococcus), clusters (see staphylococcus), or chains (see streptococcus). A rod-shaped bacterium is called a bacillus. Some species have tapered ends (fusiform bacilli) or are shaped like long threads (filamentous bacilli) or spirals (spirochetes).

On the basis of their requirements for atmospheric oxygen, bacteria can be divided into obligate aerobes, which require oxygen; obligate anaerobes, which grow only in the absence of oxygen; and facultative anaerobes, which adapt to either environment. On the basis of their growth on a specific medium under aerobic and anaerobic conditions, certain groups are divided into oxidizers, those that use oxygen to metabolize sugars; fermenters, those that metabolize sugars in the absence of oxygen; and nonutilizers, which do not grow on the medium.

Two groups of prokaryotic organisms are sometimes not classified as bacteria. These are Cyanobacteria (the blue-green bacteria), which have aerobic photosynthesis like plants; and Mycoplasma, which lack cell walls.

Bacterial Infection. The skin, respiratory tract, and gastrointestinal tract are inhabited by a variety of bacteria. These normal flora are harmless or even helpful, protecting their host by interference with the growth of harmful bacteria. An opportunistic infection occurs when an organism indigenous to one part of the body invades another part where it is pathogenic. A commonly occurring example is infection of the urinary tract with Escherichia coli or other enteric bacilli.

There are many mechanisms by which pathogenic bacteria can be transmitted from person to person, including airborne infection, direct contact, contact with animals, transmission by insect vectors, or indirect transmission in drinking water, milk, or food or on inanimate objects. Although some diseases, such as cholera and botulism, are caused by toxins absorbed in the intestine, most diseases occur from bacteria that can attach to a mucosal surface, multiply, and invade tissue. To be pathogenic, bacteria must also be able to resist the host defenses: bactericidins, such as complement and lysozyme in the blood, and phagocytosis and subsequent intracellular destruction by leukocytes.

Bacteria can cause disease by producing toxins, by causing inflammation or the formation of granulomas, or by inducing a hypersensitivity reaction. exotoxins are extremely potent poisons produced by some gram-positive bacteria. These include neurotoxins, such as tetanus toxin and botulinum toxin; enterotoxins, such as cholera toxin; and diphtheria toxin, which blocks protein synthesis, thereby causing tissue necrosis. endotoxins are lipopolysaccharides that are components of the outer membrane of gram-negative cell walls and are released on cell lysis. They can cause hypotension, fever, disseminated intravascular coagulation, and shock. Other toxins include hemolysins and leukocidins, which destroy red and white blood cells; kinases, which lyse blood clots; and enzymes that attack tissue.

Host resistance to infection is lowered in weak and debilitated patients and in those with a decreased ability to mount an effective immune response because of disease or the effects of drugs (such as corticosteroids, immunosuppressive agents, or cytotoxic agents).

A major problem in antimicrobial therapy is the evolution of antibiotic-resistant strains of bacteria, which are an important cause of serious nosocomial infections. Unnecessary overuse of antimicrobial agents speeds up the evolution of resistant strains. This problem is exacerbated by the transfer of resistance between different species by plasmids, producing multiple drug-resistant strains.

Diseases Caused by Bacteria. The different kinds of bacteria tend to affect different organs and systems of the body, producing infectious diseases, each with its own group of symptoms.

Staphylococci are generally found on the surface of the skin. When they invade the body tissue, for instance through a cut, they usually produce a local infection with inflammation and pus. Occasionally a strain of staphylococcus develops that can cause an infection affecting more than a local area of the body, but this is relatively rare.

The diseases produced by streptococci are often more serious. Streptococci tend to resist localization and may spread through the bloodstream. Among the diseases caused by streptococci are streptococcal sore throat, rheumatic fever, and scarlet fever.

Pneumonia, meningitis, and gonorrhea are produced by different types of diplococci. The pneumococcus, which produces pneumonia, has its special effect on the lungs; the meningococcus has an affinity for the meninges of the brain and spinal cord. Both types of bacteria enter the body via the respiratory tract. gonorrhea, spread by bacteria called gonococci, is usually spread by coitus.

Cholera, caused by a spirillum and spread by unsanitary water supplies, was formerly a dread epidemic disease. syphilis, like gonorrhea, is spread most often by coitus. It also is caused by a spirillum.

Bacilli are responsible for many serious diseases, including plague, diphtheria, leprosy, tuberculosis, and typhoid fever. Prevention and control of the spread of many infectious diseases can be accomplished through immunization and proper sanitary conditions.

Q. My left foot is swollen and painful. Can it be flesh eating bacteria? I am a 24 years old lady and my left foot is swollen and painful. To be more specific it is not just swollen it's red, painful and hot. I just saw a TV show few days ago about "flesh eating bacteria". I know it sounds like I have hypochondria but I am very afraid.

A. Don't feel bad for caring for yourself. Yes, the risk that this situation is flesh eating bacteria (FEB) is small (maybe we saw the same show :)) but it's important to find out. I had cellulites (the thing that mimic FEB)once, and you sound to me like you have it too.
FEB is a more systemic illness with fever and with rapid enlargement of the swelling. Mark the red area on your foot. If it grows go to the ER for antibiotic therapy.

Q. Can Cholera outbreak here in the U.S? I looked for information about Cholera and couldn’t find much…

A. You can find any information in wikipedia. here is a link about Cholera :
http://en.wikipedia.org/wiki/Cholera
and here is all the info about Cholera outbreaks in the world:
http://www.who.int/cholera/en/

Q. Are superbugs contagious through the air? Last week we visited my dad in the hospital, and we noticed that on the next room’s door there was a warning sign. After asking, we were told it was a denoting that the patient inside had a superbug (called klebsiella). On our way out we passed against this patient in the hallway – is it possible that I also carry this superbag? Is it dangerous?

A. Usually these bacteria are transmitted from person to person through direct contact, and less through the air. Moreover, these germs are dangerous in ill and debilitated patients, and not in normal healthy individuals.

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abortive transduction abscess aerobic bacteria Aminoglycosides Anaerobic bacteria Anaerobic Infections bacteremia bacteria bacterial vaginosis bactericidal bacteriuria Bdellovibrio blood culture cellulitis Escherichia coli Flesh-Eating Disease food poisoning Gram stain gram-negative			Schopf, a paleo-biologist at the University of California, Los Angeles, was struck 30 years ago by the apparent similarities between some 1-billion-year-old fossils of blue-green bacteria and their modern microbial counterparts, which often form a living film on stagnant water. Static evolution: is pond scum the same now as billions of years ago? by Pennsi, Elizabeth / Science News			blue squill Blue Suit Blue Tabs Blue Tag blue tick Blue Toe Syndrome Blue Tongue Sign Blue Tongues in Children Blue Top Tube blue tulp Blue V dye Blue Valve Syndrome Blue Velvet Blue Vials blue vitriol blue wildebeeste blue wing disease blue, methylene blue-black blue-eared pheasant blue-eared pig disease blue-gray Blue-gray cattle blue-green algae blue-green algae poisoning Blue-green bacteria blue-point blue-roan bluebag bluebell (South Africa) blueberry Blueberry Muffin Appearance Blueberry Muffin Baby bluebonnet bluebottle bluebush pea bluecomb bluegrass bluenose blues Blues & Reds bluesedge bluestem bluestone Bluetick coonhound bluetongue Blumberg Blumberg's sign Blunt blunt dissection blunt duct adenosis			blue-eyed Mary blue-eyed Marys Blue-eyed soul Blue-Eyed White Blue-Eyes Shining Dragon Blue-Eyes Ultimate Dragon Blue-Eyes White Dragon Blue-faced Leicester Blue-faced Leicester Blue-faced Leicester Blue-faced Leicesters Blue-faced Leicesters Blue-faced Leicesters Blue-faced parrot finch blue-flowered blue-fruited Blue-grass State blue-gray blue-gray Blue-gray cattle Blue-gray Gnatcatcher blue-green blue-green alga blue-green alga blue-green alga blue-green algae blue-green algae blue-green algae blue-green algae poisoning blue-green algal virus Blue-green bacteria Blue-Green Bile blue-green flame blue-grey Blue-headed Hummingbird blue-headed vireo Blue-headed Wagtail Blue-headed wrasse blue-high-fluence Blue-jacking blue-jeaned Blue-jeans Blue-jeans Blue-john Blue-leg Blue-Light Radiation Blue-Light-Regulated Promoter blue-lilac Blue-Line Copy Blue-note Blue-on-blue Blue-on-blue Blue-on-blue Blue-on-blue Blue-on-blue blue-pencil blue-pencil blue-penciled blue-penciled blue-penciling blue-penciling

bacterium (redirected from Blue-green bacteria)

bacterium
(redirected from Blue-green bacteria)