Portal de Periódicos da CAPES

Websites of note

2003; Wiley; Volume: 31; Issue: 3 Linguagem: Inglês

10.1002/bmb.2003.494031030219

1539-3429

Graham R. Parslow,

ATP Synthase and ATPases Research

This Japanese laboratory has studied the ATP synthase from a thermophilic bacterium and from thylakoid membranes of plant chloroplasts. These workers produced the experimental evidence that ATP synthase is a rotary motor, thereby confirming the binding change hypothesis that Paul Boyer put forward in 1997. The visualization of the rotation of the γ subunit in the central cavity of the ATPase used fluorescently labeled actin filaments. These impressive results influenced the Nobel prize selection for Walker and Boyer. This experiment also opened a new field of single-molecule bioenergetics so the seminal nature of this achievement makes this web site both motivational and informative for students. There is a well chosen amount of introductory text including the assertion that “One person produces and consumes his or her own body weight in ATP in a day.” This obliged me to scribble a calculation (using Mr ATP = 507) that implied that this was at least close. There are so many ways of arriving at an answer to this problem that it should make a good class exercise to calculate ATP turnover per day. Continuing from this we are told that such rapid turnover of ATP is supported by the efficient production of ATP in mitochondria and that similar enzymes are working in plant chloroplasts and bacterial cell membranes. After working through “ATP synthase—the rotary engine in the cell” you can read some brief notes on “The Proteins Caretakers: Molecular Chaperones” and “Regulatory mechanism of the various enzymes.” For lecturing you may care to download a copy of the video showing the rotating actin filament. I have found that this direct visual evidence for the way that molecules work in biochemistry makes a valuable impression on undergraduates. If you want to delve into greater structural complexity of the ATPase then try nature.berkeley.edu/∼hongwang/. By selecting the virtual classroom you will see the range of courses taught in chemistry and biochemistry at Akron. Perhaps start at the bottom with the amusing diversion titled “why I missed the exam” that leads to a list of creative excuses from students (worth a snigger). The rest of the virtual classroom is a deceptively straightforward listing of topics that acts to open a wealth of primary teaching material. The Organic Chemistry Laboratory is a portal to experiments to develop techniques in organic chemistry and illustrate principles. Analytical Chemistry I and II leads to theoretical principles of quantitative and instrumental analysis. Concepts in Biochemistry includes discussions of proteins, carbohydrates, and lipids plus a review of enzymes, DNA, and RNA. Chemical Separations provides copies of course lecture slides and animations. More choices relate to specific chemical apparatus and experimentation. An interesting assembly of ancillary materials includes a periodic table, the major metabolic pathways, and a hazardous chemical database. This is a highly recommended site to visit, particularly for the practical technique information and instructions on performing calculations. Some of the material requires permission to copy. This is an excellent motivational site for illustrating science as a practical occupation. Follow the publications link to find Forensic Biology, a publication produced by forensic science students to illuminate the criminal justice system and the laboratory procedures available to the forensic investigator to link suspect, victim, and the crime scene. Most material here is from students who have written essays based on their referenced readings. For example Juliana Bartolini tells us that “tests indicate that President Thomas Jefferson fathered his slave Sally Hemings's youngest son. Historically, Jefferson was thought to have sired Thomas Woodson, Hemings's oldest son. But in a DNA analysis published in the British journal Nature in November 1998, Eugene Foster and his colleagues presented genetic evidence from descendants of the Jefferson and Woodson families that strongly suggests that Jefferson was not Woodson's father.” In a separate essay Julia Wang has a description of the blood and DNA evidence in the O. J. Simpson trial. There are many more articles classified by the aspect of forensic science that is the central feature (like ballistics and toxicology). There is a separate link to The Science Detective, a program developed in the Bronx to excite students and teachers in schools to learn about forensic science investigations. In learning forensic approaches students learn more generally about scientific methodology and problem solving. A separate Biology News and Information Center provides additional interesting articles. Sadly nothing seems to have been added for about a year so staff changes may have compromised this commendable site. This site features the public broadcasts of a medical practitioner, turned science publicist, as presented by the Australian Broadcasting Commission (comparable to the British Broadcasting Corp.). The range of topics is awe inspiring and always phrased to capture the dramatic. I have selected one talk to précis and hope that you will make time to locate the rest of this talk and the rest of the topics brought to life by Doctor Karl. Elvis Presley was such a great legend that even today some people claim that he is still alive. He died on the toilet of his mansion, Graceland, in Memphis, Tennessee apparently from constipation! Now one of the contributing factors to the death of Elvis Presley was his diet. When he died, in 1977 at the age of only 42, he weighed 159 kilograms! But, according to some recent research, he could have lost a lot of weight by fidgeting. With Elvis, you can forget about your average 1,500–1,800 calories per day or even the 5,500 calories per day of your average Antarctic explorer. Before he died, Elvis was eating about 100,000 calories per day! That is more than enough to keep your average multiton Asian elephant alive. Professor Leonard Storlein from the Department of Biomedical Science at Wollongong University accidentally discovered the weight loss benefits of fidgeting. He found that fidgeting energy varied from 200 calories per day (for somebody who just sat around) to 1,200 calories (for a dedicated fidgeter). This 1,000 calories is an amazingly large amount. According to Professor Storlein, “A person would normally run 10 km just to get rid of 300 calories.” So 1,000 calories is equivalent to a 33-km run. In other words, your dedicated fidgeter, twiddling their thumbs, bobbing up-and-down, and crossing and uncrossing their legs, can burn up as much energy as you would need to run 33 km! Now this would not have really helped Elvis even if he was a serious fidgeter. But one thing we do know is that Elvis Presley, The King, is really dead. In an autopsy, the doctor removes and examines the heart, the brain, and various other essential internal organs. To quote the doctor, “If he wasn't dead before I did the autopsy, he sure was afterward!” The journal Nature presents this site as part of the 50th anniversary celebrations of the publication of the structure of DNA. The core content is a collection of overviews celebrating the historical, scientific, and cultural impacts of the discovery of the double helix. Items of contemporary news will be added through 2003 as will an archive including all the classic papers from 1953. All content is free. I started by reading The double helix and immunology written for this feature by Sir Gustav Nossal whom I have long admired for his clear writing. After some familiar history I encountered the following commentary on lymphocytes and cancer. A notable example of DNA science relates to the B-cell tumor of humans known as Burkitt's lymphoma. Occasionally DNA strands break and are incorrectly repaired. Thus, a piece of a chromosome becomes attached to the broken end of another one, and vice versa, in a process known as reciprocal translocation. In the case of Burkitt's lymphoma, a tumor-promoting gene or oncogene called myc is translocated from its normal position on chromosome 8 right into the middle of the IgH chain locus on chromosome 14. In this highly active transcriptional environment, myc expression is switched on, and eventually cancer develops. The highly readable style and eminence of the contributors commends this collection of essays to the attention of students and staff alike. If you received the glossy promotional pamphlet in your mail (as I did) then you may naively expect an on-line Merck index type of report on a range of enzymes. What you do get is the rather limited technical data that you would obtain in the printed Sigma product catalogue. The advantage is that finding a target enzyme is much easier. If you start at the home page (sigma-aldrich.com) you will have access to a help service that gives technical information and service support relating to all 85,000 biochemicals and organic chemicals supplied by Sigma. The Enzyme Explorer, however, is not easily reached from the home page, so typing in the full URL is recommended. The Enzyme Explorer menu has seven main choices to recover data relating to a search: 1) an index to 1,700 enzymes categorized by areas of interest such as apoptosis, signal transduction, diagnostics, and organic synthesis; 2) enzymes indexed by their enzyme commission (EC) number or by the type of reaction they catalyze; 3) inhibitors organized by their corresponding enzymes; 4) a substrate index; 5) an enzyme cofactor index classified by functions; 6) lectins; and 7) a protein kinase explorer including phosphorylation patterns. In addition to the primary data there are links to biochemical pathways and other information sites. As you might expect it is easy to make an on-line purchase order from Sigma for any of the materials that are described. Fordyce Lux, an associate professor of biology at Lander University, has provided student resources to support his teaching in general biology, biochemistry, and genetics. Choosing Selected Biology Links leads to a well catalogued series of entries within discipline areas. Genetics sites include the Virtual Flylab, Greenwood Genetics Center, and Mendelweb featuring Mendel's classic paper on heredity plus commentaries on the significance of his work. Molecular biology sites include the National Center for Biotechnology Information and numerous human genome web resources that support tasks such as predicting restriction maps and multiple sequence alignments with DNA or protein sequences. More esoteric links include the kinesin home page and the Chlamydomonas genetics center. The site is most valuable for concentrating quality links to key learning material and serving as an example of a highly serviceable on-line aid to students. If you want to download some molecular visualization software the links here make it particularly easy.