Caves of crystal

Geologists have explained how the giant crystals in Mexico’s Cueva de los Cristales, Naica, were formed. The 11-metre-long translucent gypsum beams are among the largest in the world.  

Subsiding volcanic activity kept the temperature at 58°C - the transition temperature between anhydrite (pure calcium sulfate) and gypsum (calcium sulfate dihydrate) - for hundreds of thousands of years, said Juan Manuel García-Ruiz, of the University of Granada, Spain, who reported his team’s analysis in Geology. Those were the perfect conditions for growing large crystals very slowly, the scientists say. 

Blood conversion 

Blood from groups A, B, and AB could be converted into the universal type O, say scientists who have identified new glycosidase enzymes which strip the sugar-based antigens ’A’ and ’B’ from red blood cells. This avoids the immune reactions which patients face if they are given a blood transfusion of the wrong group. Type-O blood is suitable for all, but stocks run low as it is always picked in an emergency. 

The team led by Henrik Clausen of the University of Copenhagen, Denmark, publishing in Nature Biotechnology, hope their research will find commercial use in blood centres. Early-stage clinical trials are underway; the technology is being developed by Boston-based company ZymeQuest. 

Poor at climate risk 

The second report from the Intergovernmental Panel on Climate Change (IPCC), focusing on impacts, adaptation and vulnerability, warned that the poorest would suffer most from the effects of climate change.  

Up to 250 million Africans could face water shortages by 2020, while drought would damage agriculture at low latitudes. 

A third report, due in May, will focus on how to curb the rise in greenhouse gas concentrations and temperatures, while a final summary is expected in November. 

Clinical trials to change 

New ’first-in-man’ (Phase I) clinical trial guidelines have been released for public consultation, following recommendations after the disastrous March 2006 monoclonal antibody trial that left six subjects fighting for their lives (see Chemistry World, September 2006, p14). 

The guidelines advise on the transition from in vitro or animal studies to humans, including calculating first doses, dose-escalation, and managing risk. For further information go to website.

Harmonising pharma 

The European Pharmacopoeia, the Strasbourg-based organisation responsible for European pharmaceutical quality standards, has opened its new €36.3 million (£24.5 million) headquarters.  

In June, 400 delegates will meet there to discuss harmonising the European, American and Japanese pharmacopoeias, establishing worldwide drug quality standards. 

Medicines authorised in Britain and 35 other countries must conform with Strasbourg standards. The Pharmacopoeia, with its parent body, the European Directorate for the Quality of Medicines and Healthcare (EDQM), operates alongside the European Commission, which determines legislation. Safety and efficacy evaluation is handled by the European Medicines Agency (EMEA). 

Joan myth debunked 

Supposed relics of St Joan of Arc - the French heroine burned at the stake in 1431 - are forgeries, French forensic scientists have revealed. 

Carbon dating placed the human rib, cat femur, and linen remains between the third and sixth centuries BC; electron microscopy showed the charred black crust on the bones was not burnt tissue, but mineral and vegetable residues; while spectrometry and electron microscopy matched the relics with Egyptian mummies.  

Philippe Charlier, of the Raymond Poincaré Hospital in Garches, near Paris, who led the research, explained that Egyptian mummies were commonly used in pharmaceutical remedies in Europe’s Middle Ages. 

Russians cling on 

The Russian Academy of Sciences has rejected government demands that it give up some of its autonomy.  

Members of the academy, which was founded in 1724 by Peter the Great, voted against an official charter requiring science funding and management to be decided by a supervisory board whose members were appointed by parliament. This insistence followed government conclusions that the academy’s structure was inefficient and required new standards. 

Instead, academy members voted for their own new charter, saying the government’s plan was a threat to independent scientific research. 

Fatty acid factory revealed 

X-ray crystallographers in Switzerland have solved the structure of one of biochemistry’s most impressive molecular machines, the multi-enzyme fatty acid synthase.  

The project took more than five years to complete and shows the protein’s 2.6 MDa structure at 3.1Å resolution; two dome-shaped reaction chambers, each housing three complete sets of enzyme activities, lie either side of a central equatorial wheel.  

A second Swiss team, also publishing in Science, have explained how the enzyme, studied in fungus and yeast, constructs the fatty acid chain from its substrate. 

Pipsqueak pipette 

The world’s smallest pipette has been developed by US scientists: it is made from a germanium nanotube surrounded by graphene sheets pierced at the tip. It can dispense drops of a molten gold-germanium alloy with a volume of a few zeptolitres (10-21 litres), smashing the previous attolitre record. 

The drops contain only a few thousand atoms, say Eli and Peter Sutter of the Brookhaven National Laboratory, New York, reporting in Nature Materials. That is too large for computers to simulate, but small enough to behave differently to bulk liquids when cooled. With no impurity for crystals to grow around, the drops solidified from the outside in.  

CO2  is air pollutant 

The US Supreme Court has forced the Environmental Protection Agency (EPA) to draw up regulations on carbon dioxide emissions from car exhausts. The legal case had been brought by 12 US states and environmental campaign groups.  

Judges brushed aside the defence that the gas was not subject to EPA restriction as it did not meet the 1970 Clean Air Act’s definition of a pollutant.  

The EPA must now either provide evidence that CO2 does not ’endanger public health or welfare’, or regulate it. But there is no timeline for this requirement. A spokesperson said the EPA was reviewing the court’s decision. 

T. rex protein record 

Palaeontologists and biochemists in the US have sequenced collagen proteins from a 68-million-year-old Tyrannosaurus Rex. The proteins are close to those of modern-day chickens, supporting the evolutionary link between birds and dinosaurs.  

The T. Rex  skeleton had been found preserved under 1000 cubic metres of sandstone in Montana, US; fibrous soft tissues discovered inside the bones were analysed with ion-trap mass spectrometers.  

The researchers, reporting in Nature, hope to extract more proteins from ancient bones, perhaps discovering some unique to dinosaurs. DNA, however, is thought far too fragile to survive, lasting at best just 30,000 years.  

Tamiflu banned for teenagers 

The Japanese Health ministry has advised doctors not to give Tamiflu (oseltamivir), to minors over the age of 10. The warning follows reports of teenagers jumping from buildings while taking the neuraminidase inhibitor, which is widely prescribed in Japan for flu, and also considered as a defence against bird flu. 

Swiss company Roche, who manufacture the drug, said large-scale statistical trials show flu patients face less risk of neuro-psychiatric disorders when they take Tamiflu.  

The European Medicines Agency recommended a labelling update for the drug, and is closely monitoring the situation, but said Tamiflu’s benefits outweighed its risks.  

Drug combos tackle resistance 

Combinations of some antibiotics can help non-resistant strains of bacteria grow at the expense of resistant ones, say US scientists. The surprising finding may provide a general strategy to cope with bacterial resistance - by promoting non-resistant growth before counterpunching with effective drugs.  

Roy Kishony and colleagues at Harvard University, publishing in Nature, found that Escherichia coli  resistant to tetracycline antibiotics wilted, compared to their non-resistant neighbours, when cultured on doxycycline and ciprofloxacin. The synergistic effect between the two drugs responsible has not yet been identified.