Scientific Foundations

In nature, there are insects that feed on crops. Humans consider these insects to be pests. There are also other insects and diseases that naturally kill those insect pests. Biological pest control uses these natural killers to target the pests that are damaging crops. Predators, parasitoids, and pathogens are considered the natural enemies of crop pests. Predators are insects, such as ladybugs or spiders, which kill specific types of insects. These predators can be used to control insect...

Fantastical Experiment

In 1952, scientists Robert Briggs and Thomas J. King used nuclear transfer to clone frogs. Although they later claimed to be unaware of Hans Spemann's work their experiment was similar to what Spemann proposed in 1938 as ''a 'fantastical' experiment.'' Briggs and King tried to clone tadpoles using donor nuclei obtained from older cells (differentiated cells) but found that the embryos did not develop or that they developed abnormally and that genetic potential diminished as cells from older and...

The Unintended Side Effects of Introduced Predators

Sometimes introduced predators become a bigger problem than the pests they were introduced to control. For example, barn owls were introduced in Mauritius in the 1940s and 1950s to control rats. They certainly ate the rats, but also preyed upon native species of birds, such as fairy terns, and there is now a reward for killing barn owls. The small Indian mongoose was introduced to a number of Caribbean islands in the nineteenth century to kill the rats and snakes that infested sugarcane fields....

Development

Fingerprints were used to sign legal documents in ancient times. Czech physiologist Jan Evangelista Purkinje (1787-1869) is considered the first person to study fingerprints scientifically, and in 1823, he proposed a system for their classification. The Scottish physician Henry Faulds (1843-1930) published a paper in 1880 in which he recommended that bloody finger impressions left on porous materials be used to identify criminals. Although English police rejected his idea, his work is...

Description

Enzymes are substances that speed chemical reactions occurring in living organisms. These chemical reactions control all the functions of the body, and enzymes play a vital role. In the absence of appropriate enzymes, reactions slow down and negatively affect a living system. For example, the human digestive system maintains energy levels by breaking down food into forms easily absorbed and distributed by blood. Helping in the digestion process are gut enzymes such as trypsin and pepsin that...

Current Issues

Biochips are being used today to do DNA screening and to study gene expression in cancer cells, as well as for many other purposes. In 2005, the U.S. Food and Drug Administration approved a biochip test system called the AmpliChip Cytochrome P450 Genotyping Test, made by Roche Molecular Systems, Inc. Cytochrome P450 genes affect how the liver breaks down some drugs. Every person has slightly different P450 genes. The AmpliChip contains different versions of the P450 genes on its surface. DNA...

Preventing Citrus Canker with Sentinel Like Plants

Scientists use this plant as a model for sentinel plants because it has a simple structure, it is found commonly around the world, and its entire gene sequence has been worked out. Arabidopsis, along with other plants, notices and responds to things through cellular proteins called receptor-like kinases (RLKs). (Proteins are substances in cells that control their functions.) Arabidopsis has more than six hundred RLKs, but scientists have identified only about ten...

What Causes Holes in Swiss Cheese

Three kinds of bacteria are used in the production of Swiss cheese. One of these, Propionibacter shermani, is introduced late in the cheese-making process. It consumes the lactic acid excreted by other bacteria and releases carbon dioxide gas. This gas slowly forms bubbles and gives the cheese its characteristic holes (known as eyes). Although the basic process for making cheese remains the same, advancements in biotechnology have enabled dairy farmers to improve the quality of cattle. These...

Developlment

Experiments proving that some animals have the sense of mag-netoreception were not done until the 1960s. It was also shown in the 1960s that some bacteria contain tiny particles of magnetite that they use as compasses. Today, many questions remain unanswered about how some animals sense the Earth's magnetic field. (Humans, as far as anyone knows, cannot.) The magnetic field of the heart was first measured in 1967 by physicist David Cohen. In 1968, Cohen first measured the magnetic field of the...

Words to Know

Immune rejection Immune system rejection of a foreign substance. Xenograft Tissues and organs used for transplantation that come from different animal species, like pigs or baboons. Xenotransplantation Transplantation of tissue or an organ from one species to another, for example from pig to human. called acute vascular rejection. Furthermore, transplant studies using pigs as the donors and non-human primates as the recipients have demonstrated that suppression of the immune system is not...

Developzment

Green chemistry was created in the 1980s to minimize the environmental problems and economic costs that sometimes occur with products and services. Governments of developed countries began making companies accountable for the products and services they introduce. Based on government regulations, companies are forced to clean up problems that they create with respect to such activities as chemical storage and disposal and environmental emissions. In the United States, the use of green chemistry...

Retroviruses Rejected for Gene Therapy

In 2000, French researcher Alain Fischer was able to cure children of a similar kind of immune system disorder. Fischer used retroviruses as gene carriers. Retroviruses are a type of virus that uses ribonucleic acid (RNA) as its genetic material, instead of DNA. Retroviruses produce an enzyme (a protein that controls a biochemical reaction) that builds DNA upon a strand of RNA (the opposite of what normally happens in humans where RNA is made on sections of DNA). The most well known of these...

Ancient Roman Cosmetic Unearthed

In 2004 archaeologists in London found a pot with a lid containing a Roman beauty cream. The pot has been dated to the middle of the second century ce. An analysis of the cream showed that it was made of refined animal fat (probably from a cow or sheep), starch, and tin oxide. Although the Romans had traditionally used lead acetate as the coloring agent in their face creams, this cream contained tin oxide, probably from the ancient Cornish tin industry in western England. Unlike lead, tin had...

Eurofresh Farms Produce Hydroponic Tomatoes

Various fruits and flowers without the use of soil. In 1937, Gericke created the word hydroponics from two Greek words hydro (water) and ponos (labor). Although his way of performing hydroponics was considered too difficult for commercial farming, his work is still considered the foundation for all types of hydroponics. In the late 1940s, American horticulturists Robert B. Withrow and Alice P. Withrow, of Purdue University, designed a practical hydroponic system. The U.S. and British militaries...

Silk Making Goats

Why would scientists focus on goats to make spider's silk Because goats already contain the basic machinery for producing the silk proteins in their milk. Plus, a goat can make silk proteins in much larger quantities than a spider can. A single goat can produce about 1,000 quarts 950 liters of milk per year. Each quart can contain between one and ten grams of spider's silk, a significant amount considering one gram can stretch 9,000 yards 8,200 meters . of silk. To produce larger amounts,...

What Are The Current Issues Beekeepers Face

Beekeepers face at least two serious problems in maintaining their hives. Many diseases occur when bees are placed in hives more crowded than their natural environment. Consequently, the bees are more likely to die. Fewer bees means fewer colonies of bees, which results in less honey produced and less crops pollinated. Also, the expensive equipment used for beekeeping can easily become contaminated. In many cases, such equipment must be destroyed when contamination cannot be removed. Because of...