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Protozoa That Cause Disease

Diseases caused by protozoan parasites are among the leading causes of death and disease in tropical and subtropical regions of the world. Developing countries within these areas contain three-quarters of the world's population, and their populations suffer the most from these diseases. Controlling parasitic diseases is a problem because there are ...

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ProtozoaThatCauseDisease
Biology

When A Bass Isn't A Bass

Chilean Sea Bass, a very popular though overfished deep-sea fish, is not a bass at all. It is actually a Patagonian Toothfish (Dissostichus eleginoides), or sometimes its cousin, the Antarctic ... Continue reading

SeaBass
Engineering

A Shear Mystery

Everyone has had problems with a ketchup bottle at one time or another. After struggling and only getting a few drops, a flood suddenly gushes out and buries your food. With perfect timing, the ... Continue reading

ShearMystery
Geology

The Importance of Cave and Karst Systems

Cave and karst systems are important for two major reasons. First, the overwhelming majority of the nation's freshwater resources is groundwater. About 25% of the groundwater is located in cave and ... Continue reading

ImportanceofCaveaKarstSystems
Physics

Ultraviolet Light

Ultraviolet light is a form of radiation which is not visible to the human eye. It's in an invisible part of the 'electromagnetic spectrum'. Radiated energy, or radiation, is given off by many ... Continue reading

UltravioletLight

Resistance is NOT Futile!

ResistanceisNOTFutileMaybe if you are a Star Trek heroine up against the Borg, 'resistance is futile.' But if you are a germ that makes people sick, resistance - to antibiotics - is not futile at all.

When penicillin began to be widely used over fifty years ago, it could kill most of the bacteria that made us sick. Such bacteria are called 'pathogens,' to distinguish them from the many bacteria that are harmless or even useful. Nowadays, many pathogens are 'resistant' to a lot of the antibiotics we use to combat them. They have evolved the ability to fight off the effects of the drugs, so the drugs cannot cure you. This can be very dangerous in hospitals, where drug-resistant pathogens can spread rapidly and kill many people.

How can bacteria evolve drug resistance so quickly? The genes for drug resistance are usually not carried as part of the regular chromosome, but on extra rings of DNA called plasmids. These can be passed on to the bacterial cell's descendants, and can also sometimes be passed around to any other bacteria that happen to be in the area, even those of other species. If a drug kills all the susceptible bacteria, any few that are resistant will be free to multiply without competition and take over the population. So we are involved in an 'arms race' between biologists and chemists inventing new antibiotics, and pathogens inventing new ways to resist them.