Virus Cyanobacteria

Cyanobacteria (a.k.a. blue-green algae)

TYPE: Bacterium (although considered a form of algae for years)

FAVORITE HANGOUT:WaterLIKES:Producing oxygen.

AGE:3.5 billion years. Cyanobacteria fossils are among the oldest known fossils.Cyanobacteria are the progenitors of algae and plants. The chloroplasts with which plants convert sunlight into energy derived from cyanobacteria that took up residence in eukaryotic cells millions of years ago.

DNA Discrupter and Single-Minded Mission

DNA Disrupter

Viruses can act as miniature couriers. When they infect, they may inadvertently take up a bit of their host’s DNA and have it copied into their progeny. When the offspring viruses move on to infect new cells, they may insert this bit of accidentally pilfered DNA into the new hosts’ genome. This process is called transduction.

This can sometimes create a happy outcome. For example, the soil-dwelling bacterium Bacillus subtilis has viral genes that help protect it from heavy metals and other harmful substances in the soil.

Other times, viruses can wreak havoc when they bring in new genes. For example, Vibrio cholerae, the bacterium that causes cholera, is harmless in itself. The disease-causing toxin that causes illness is actually made by a virus that at some point smuggled itself into its host’s genome.

Viruses can also influence host genes by where they insert themselves into their host’s DNA. Recent decoding of the human genome shows that viral DNA sequences have been reproducing jointly with our genes for ages.

Some of these DNA sequences stay put, but others seem to move about our genome, jumping from place to place on a chromosome or from chromosome to chromosome. These “mobile elements” take up nearly half of the human genome.

Hemophilia and muscular dystrophy are two human diseases that researchers now believe resulted from mobile elements that, while skipping about the genome, ungraciously barged right into the middle of key human genes.

Single-Minded Mission

Viruses exist for one purpose only: to reproduce. To do that, they have to take over the reproductive machinery of suitable host cells.

Upon landing on an appropriate host cell, a virus gets its genetic material inside the cell either by tricking the host cell to pull it inside, like it would a nutrient molecule, or by fusing its viral coat with the host cell wall or membrane and releasing its genes inside. Some viruses inject their genes into the host cell, leaving their empty viral coats sitting outside.

If a virus is a DNA virus, its genetic material then inserts itself into the host cell's DNA. If the virus is an RNA virus, it must first turn its RNA into DNA using the host cell's machinery before inserting into the host DNA. The viral genes are then copied many, many times, using the machinery the host cell would normally use to reproduce its own DNA. The virus uses the host cell's enzymes to build new viral capsids and other viral proteins. The new viral genes and proteins then come together and assemble into whole new viruses. The new viruses are either released from the host cell without destroying the cell or eventually build up to a large enough number that they burst the host cell like an overfilled water balloon.

How the virus Virus do contact

When viruses come into contact with host cells, they trigger the cells to engulf them, or fuse themselves to the cell membrane so they can release their DNA into the cell.Once inside a host cell, viruses take over its machinery to reproduce. Viruses override the host cell’s normal functioning with their own set of instructions that shut down production of host proteins and direct the cell to produce viral proteins to make new virus particles. Some viruses insert their genetic material into the host cell’s DNA, where they begin directing the copying of their genes or simply lie dormant for years or a lifetime. Either way, the host cell does all the actual work: the viruses simply provide the instructions. Viruses may be able to infect and reproduce in more than one kind of animal, but the same virus can cause different reactions in different hosts.
For example, flu viruses infect birds, pigs, and humans. While some types of flu viruses don’t harm birds, they can overwhelm and kill humans. Plant viruses do not infect animals or vice verse. Viruses that infect bacteria do nothing to animal or plant cells.

Virus

What They Are?
A virus is basically a tiny bundle of genetic material—either DNA or RNA—carried in a shell called the viral coat, or capsid, which is made up of bits of protein called capsomeres. Some viruses have an additional layer around this coat called an envelope. That's basically all there is to viruses. Microbes are single-celled organisms that can perform the basic functions of life — metabolism, reproduction, and adaptation. Except viruses. Viruses can’t metabolize nutrients, produce and excrete wastes, move around on their own, or even reproduce unless they are inside another organism’s cells. They aren’t even cells. Yet viruses have played key roles in shaping the history of life on our planet by shuffling and redistributing genes in and among organisms and by causing diseases in animals and plants. Viruses have been the culprits in many human diseases, including smallpox, flu, AIDS, certain types of cancer, and the ever-present common cold.

What is Microbiology?

Microbiology is the study of microorganisms - little, really little, And, please take a look at some relative sizes of different living cells at Jim Sullivan's page. These "bugs" include: bacteria "that's the Latin plural for bacterium"; viruses "that's the non-Latin plural for virus - virii sounds weird, so I don't say it"; and, fungi "that's the Latin plural for fungus - which by now you have guessed, or already knew, and may not be all that interested to know, anyway". Microbiology is actually made up of several sub-disciplines which individually may stand alone, because there is so much to learn in each. These disciplines include: Immunology "the study of the immune system and how it works to protect us from harmful organisms and harmful substances produced by them - is what I, Marci, and Larry work on; Virology, the study of viruses, and how they function inside cells - Marci does some of this, too; Pathogenic Microbiology, the study of disease-causing critters and the disease process - is what Eric does; Microbial Genetics, the study of gene function, expression, and regulation - is what Susan and Del do - although Del mostly examines mutations in genes and substances which appear to prevent mutations; Physiology, the study of biochemical mechanisms - is what Jim and Clarence do. I'll focus on bacteria right now, not because this group of critters is necessarily more interesting, but because I know very little about fungi, and because I don't want to talk about viruses just now.
Bacteria are absolutely necessary for all life on this planet - for every known ecosystem - including the human ecosystem! Without bacteria, there would be no life, as we call life, on the earth. However, it is a good thing that most bacteria die-out. Here is why: bacteria are single-cell organisms, that produce more of their kind by cell-division, alone. So, if one begins with a single bacterial cell like E. coli for example, in 20 minutes there will be two, and 20 minutes later, four, etc., E. coli cells. At this rate, even though most bacteria are several hundred-times smaller than we can see with our naked eye (never seen a clothed eye), in only 43 hours, from that one cell at the beginning, there would be enough E. coli to occupy the entire volume of the earth (1,090,000,000,000,000,000,000 cubic meters)! In only about two additional hours, these bacteria would weigh as much as the earth - 6,600,000,000,000,000,000,000 tons! Bummer! Luckily for us, most bacterial cells die because of the enormous competition for food, and because of other tiny organisms which produce substances (antibiotics) that kill them - you know, like penicillin, which is made by a particular fungus, the mold - Penicillium). Thank goodness for that one, huh? Actually, many antibiotics are made by certain bacteria too, and, we get many of our necessary vitamins and nutrients from bacteria by allowing the bacteria to multiply in number, and isolating the things that they make, that we cannot make. For example, amino acid supplements are available ("enriched" bread simply means that the amino acid, lysine, which we absolutely need, but cannot make ourselves, is added to the flour used to make the bread), to provide one additional source which most people will eat. This amino acid is produced by certain bacteria grown in huge vats (can be 20,000 liters at one time - that's about 1,500 gallons!), and purified for our use. Antibiotic production is similarly done.
With the advent of molecular genetics and recombinant DNA technology, bacteria now play a very important role as producers of human substances. Since we have learned how genes function, we are able to introduce a human gene into a bacterium and have the product of the human gene expressed. Consequently, a hormone called erythropoietin, which is absloutely necessary for the proper development of red blood cells (erythrocytes), but very, very, difficult to isolate, is now available in high quantity. People who do not have kidneys cannot make this hormone; however, because the hormone has been cloned into bacteria, plenty of this hormone can be made, purified, and given to these people. Human insulin can be similarly made. These are only two examples of the many substances now available to treat human disorders because of our understanding of bacteria.