(August 2004) Stem cells have generated more excitement, scrutiny and controversy than any other area of recent scientific study. The first stem cells, which were discovered half a century ago, were isolated from blood. Now, scientists around the globe are researching various types of stem cells for their potential to regenerate lost tissue and revolutionize medicine. Embryonic stem (ES) cells are derived from the embryo when it exists as a blastocyst. They have the ability to develop into all the different cell types found in the body. Actually, when a sperm fertilizes an egg, the resulting single cell begins to…

(August 2003) Food spoilage has been an important problem throughout human history. Finding ways to overcome this problem was crucial as communities became larger and individuals no longer grew their own food. Some kind of system was needed to maintain the nutrient content of various food stuffs for long periods of time and prevent them from rotting and becoming inedible. Early solutions to food spoilage Food spoilage is caused by the growth of microorganisms, primarily bacteria and fungi, that convert nutrients into energy which they use for their own growth. Depletion of the nutrient content of food as well as…

(August 2004) Beer was created in 2000 B.C. when Egyptians first discovered how to ferment yeast. In 500 B.C., the Chinese invented a crude antibiotic from moldy soybeans curds and used it treat boils. These discoveries indicate an early human awareness of biology’s usefulness in creating medical and agricultural advances and for over four thousand years the industry of biotechnology has flourished, growing into a multibillion-dollar cutting edge industry over the last 30 years. The biotechnology revolution was heralded by two cornerstone discoveries: recombinant DNA and hybridomas1. Lucrative product applications had an immediate impact on industrial and agricultural developments, but…

(August 2003) “Those who cannot remember the past are condemned to repeat it.” — George Santayana “In the realm of bioethics, the evils we face are intertwined with the goods we so keenly seek. Distinguishing good and bad thus intermixed is often extremely difficult.” — Leon R. Kass MD, PhD Chairman, The President’s Council on Bioethics Since the announcement that the entire human DNA genome had been sequenced in June 2000, newspapers around the world have been rife with proclamations describing how this information is being used for the prevention and treatment of genetic disorders. Among the most promising and…

(August 2004) Aging can be characterized as: (1) an inevitable consequence of being a multicellular organism; (2) associated with a random, passive decline in function; (3) leading to a global loss of homeostasis (the state of sustained equilibrium in which all cells, and all life forms, exist) over time; and (4) mortality increasing with age [1]. Age is not a disease, but it does predispose an organism to a variety of diseases [2], in the case of humans, this includes heart disease, arthritis, osteoporosis, diabetes, cancer and Alzheimer’s. Achieving longevity is thought to be caused by a combination of factors.…

(August 2004) With the advent of the human genome project, a vast amount of information about genes and gene structure is suddenly at our fingertips. But this information is limited. Every cell within an organism has the same genetic composition (with the exception of its gametes), and yet, obviously skin tissue is very different from nervous tissue. The DNA sequence cannot provide information about these differences, which represent the next level of complexity and organization within an organism: DNA expression. Cells within a multicellular organism, such as ourselves, specialize to perform specific functions to increase the efficiency of the organism.…

(August 2003) The separation of DNA/RNA fragments or a protein sample based on size can be useful in many applications, but visualizing samples on a gel does not give any information about the identity of the sample (i.e. which gene fragment, mRNA or protein you are looking at). So how can you pick out the band you’re interested in? E.M. Southern answered this question when he developed a method that was subsequently named after him, the Southern Blot. Figure 1. The layout for a Southern Blot. The Southern Blot takes advantage of the fact that DNA fragments will stick to…

(August 2003) The Polymerase Chain Reaction (PCR) is an important tool for many applications. For example, it can be used to amplify a sample of DNA when there isn’t enough to analyze (e.g. a sample of DNA from a crime scene, archeological samples), as a method of identifying a gene of interest, or to test for disease. The method uses specifically designed primers that are complementary to the sequence to be amplified. The primers provide a starting point for the extension of the DNA by a DNA polymerase (usually Taq or Pfu polymerase). Amplification is carried out in cycles. First,…

(August 2004) Intelligence is a very difficult concept to define. Intellect is described as “the power of the mind to think in a logical manner and acquire knowledge” [1]. Even psychology experts have not agreed upon what this actually means [2]. Intelligence can be divided into various subcategories such as reasoning, problem solving, and memory, and so creating a consistent scale by which one can measure intelligence is quite difficult. Figure 1. IQ testing is a widely used measure of g. Many researchers working on intelligence use a psychometric definition for intelligence, termed “general mental ability” or the “g factor”.…