• Pick up a fistful of garden soil and you're holding hundreds if not thousands of different kinds of microbe in your hand. A single teaspoon of that soil contains over 1,000,000,000 bacteria, about 120,000 fungi and 25,000 algae.
• Antony van Leeuwenhoek (1632-1723) and his microscope.
• Louis Pasteur (1822-1895) working in his laboratory.
• Robert ch (18431910)
Examining a specimen in his laboratory.
called the Galapagos Vent.
• Some scientists even believe there is the possibility bacteria may have once lived on Mars. This photograph taken through a microscope shows what some scientists believe may be the fossils of tiny bacteria in a rock that formed on Mars about 4.5 billion years ago. The rock crash-landed on Earth as a meteorite thousands of years ago.
• Bacteria consist of only a single cell, but don't let their small size and seeming simplicity fool you. They're an amazingly complex and fascinating group of creatures. Bacteria have been found that can live in temperatures above the boiling point and in cold that would freeze your blood. They "eat" everything from sugar and starch to sunlight, sulfur and iron. There's even a species of bacteria—Deinococcus radiodurans—that can withstand blasts of radiation 1,000 times greater than would kill a human being.
• Two fundamentally different types of cells exist. Procaryotic cells have a much simpler morphology than eucaryotic cells and lack a true membrane-delimited nucleus. All bacteria are procaryotic. In contrast, eucaryotic have a membraneenclosed nucleus; they are more complex morphologically and are usually larger than prokaryotes. Algae, fungi, protozoa, higher plants, and animals are eucaryotic. Procaryotic and eucaryotic cells differ in many other ways as well.
pollution break up.
• We're using bacteria, like those pictured here, as one of the tools to clean up oil spills, like the Exxon Valdez mess. These bacteria chow on the oil, turning it into carbon dioxide and other harmless by-products.
• Other heat-loving microbes live in volcanic cracks miles under the ocean surface where there is no light and the water is a brew of poisonous arsenic, sulfur and other nasty chemicals. The little blobs shown in this photo are bacteria that live on mussel shells around a volcanic vent
• Diatoms have hard shells made up in part by silica, or glass. When diatoms die, these shells sink to the bottom. They are mined and used to make products we use everyday. For example, diatom shells are the grit in your toothpaste and the stuff that makes painted stripes on the road shiny.
• This is a cowpea virus, which infects certain bean plants including snap peas, pinto beans, green beans and, of course, cowpeas.
• This image was created by a computer.
• This is protozoan called paramecium (pair-ah-me-see-um). It looks hairy because it's covered by long, thin projections called cilia (silly-uh). The cilia beat in a regular, continuous pattern, moving the paramecium through its freshwater home and sweeping food into the mouth-like opening you can see on its side.
Early Bacterial Exposure May Extend Fly Life
Exposure to bacteria during the first week of adult life increased Drosophila lifespan, but exposure late in life decreased longevity, new research reports. All animals develop in at least partially sterile environments and are colonized by bacteria soon after birth. In model organisms such as zebrafish, paramecia, and various mammals, scientists have noted that microorganisms can have a profound effect on the animal’s health, especially on digestion, conditioning the immune system, and longevity. Seymour Benzer from the California Institute of Technology and colleagues investigated a possible connection between the microscopic fauna on Drosophila and longevity by growing the fruit flies in sterile environments, then periodically exposing them to non-sterile conditions. The researchers report that flies grown only under sterile conditions had a 30% decrease in mean lifespan. Further, Benzer’s team discovered a window of time during which bacterial exposure is beneficial: exposure to bacteria during the first 4-7 days of adult life produced the full life-extending effect, while exposure after 7 days had no beneficial effect. Alternatively, the researchers found that transferring adult flies from normal conditions to a sterile environment, effectively removing bacteria late in life, showed a 10% increase in longevity. Additional experiments with mutant fruit flies provided evidence that microscopic fauna interact with the host on a genetic level. Benzer and his team indicate that model organisms such as Drosophila may give important clues to understanding longevity in humans and other animals.