Human beings are still in the middle of evolution and human language and intelligence could be brought up to a much higher level than we are at now, say scientists from the Riken Brain Science Institute in Japan. Their monkeys, in the laboratory for symbolic cognitive development, are able to imitate humans and call for a rake, which they use to reach food--something that monkeys have seemingly never done before. Atsushi Iriki, winner of the 2004 Golden Brain Award, says that these experiments tap into neural systems monkeys have always had, but have never used. He hopes that they will contribute not only to the understanding of how monkeys think, but also of how language evolved, which may ultimately help to explain the cause of human conditions such as autism. Furthermore, he points out, if monkey brains have redundant capacity, why not human brains (www.guardian.co.uk)

Carbon nanotubes are tiny cylinders of carbon atoms, measuring just a nanometre in diameter and unique in that they emit a characteristic fluorescent light in the near infrared portion of the spectrum. American scientists have recently documented the uptake of nanotubes by living white blood cells. They incubated cells derived from mice in dilute solutions of nanotubes, whereupon the latter were actively ingested and sealed off in intracellular phagosomes. The nanotubes caused no measurable changes in cell functions or characteristics and retained their optical properties even inside the cell. This allowed the researchers to find their exact location within the cell, using a specialised microscope. Carbon nanotubes could potentially be used as novel biological imaging agents, argue the researchers (www.eurekalert.org).

A team of international scientists believes to have identified some of the key genes involved in our body's immune response to HIV and possibly other human pathogens. In a study with 375 HIV-1 infected subjects from southern Africa, they analysed the response of cytotoxic T cells to the different types of HLA (human leucocyte antigens) class I molecules. They found that HLA type B had significantly more weight in the body's immune response to HIV-1 than the other two types (A and C). Furthermore, they found that the rate of disease progression was linked to certain HLA type B alleles only, in other words, the severity of the disease depended mainly on the kind of HLA type B genes a person carried. It has previously been observed that HLA type B alleles evolve more rapidly than the other two types. The researchers argue that our immune response not only triggers mutations in HIV, but that HIV and other pathogens equally promote the evolution of HLA (Nature 2004;432:769).

Out of the millions that try, only one (lucky one) gets through. Scientists of Brown University in Providence, Rhode Island, USA, have found an enzyme that may be responsible for the hardening of the membrane occurring once a sperm has penetrated an egg and stopping further sperms from entering. By studying fertilisation in sea urchins, they discovered an enzyme they dubbed Udx1 (urchin dual oxidase 1), that catalyses the production of hydrogen peroxide, a toxic compound. When they inhibited Udx1, the egg's membrane did not harden, and many sperms entered the cell. The researchers also said that Udx1, which sits on the egg's membrane, has a dual activity, thereby preventing damage to the fertilised egg from the peroxide: They claim that it not only converts oxygen into peroxide, but also cleaves peroxide that is not used to harden the membrane into harmless water molecules. Further research still has to confirm the presence of a similar enzyme in human eggs (http://sciencenow.sciencemag.org).

Multidrug resistance in Streptococcus pneumoniae has made this pathogen more dangerous than ever. Several strains now survive exposure to vancomycin, currently one of our "last lines of defence" against bacteria. The recent discovery of a "molecular Achilles' heel," however, could signify the end of Streptococcus pneumoniae. Researchers have found a way to interrupt a pathway that determines its virulence. An intermediate in this pathway, diphosphomevalonate is a so called negative retroregulator and inhibits the first of the many enzymes responsible for the synthesis of isoprenoids. "If you switch this pathway off, the organism is in big trouble," says Prof Thomas Leyh of the Albert Einstein College of Medicine in New York. Remarkably, the corresponding human enzyme does not seem to be affected by this inhibition. However, the scientists have so far only shown that their theory works in mice. (www.eurekalert.org).

A substance derived from tofu may help to repair damaged bones and teeth, according to an international team of scientists. They are developing a gel with which surgeons and dentists will be able to fill in gaps that are too big for the body to fix itself. It works like a scaffold and, while biodegrading, allows the bone or tooth to grow into the scaffold, they found. Thanks to the release of natural anti-inflammatory agents, allegedly, this new material may also trigger less autoimmune reactions than the materials that are in use at the moment. The researchers believe that their product has potential for use as dental implants, bone implants, and also in wound healing (http://news.bbc.co.uk).

It's not chalk, it's not cheese, it's tofu

By injecting phospholipase C *, an enzyme produced by sperm, into human eggs, the latter could be fooled and persuaded to divide as if they had been fertilised, researchers have found. "It's the spark of life," says Karl Swann, from the University of Wales College of Medicine, Cardiff, who was involved in the discovery. The tricked eggs divide for four or five days until they reach the blastocyst stage. These blastocysts potentially contain embryonic stem cells. Because they are parthenogenetic (produced from the egg only and devoid of paternal chromosomes), they cannot be viewed as potential human life, according to Dr Swann. Therefore, this technique may supply embryonic stem cells by bypassing the ethical objections to existing techniques (www.newscientist.com/news).

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