Virology

Role for influenza virus envelope cholesterol in virus entry and infection Sun, X. & Whittaker, G. R. J. Virol. 77, 12543–12551 (2003)

Lipid microdomains or 'rafts' rich in cholesterol have been identified as important budding sites for several different enveloped viruses, including HIV and influenza. Cholesterol levels in the host-cell membrane do not affect influenza virus entry, but depleting cholesterol from the envelopes of influenza virions showed that although virus morphology was unaffected, entry and infection were inhibited.

Anti-infectives

A genetic basis for Pseudomonas aeruginosa biofilm antibiotic resistance Mah, T. -F. et al. Nature 426, 306–310 (2003)

Antibiotic resistance in biofilms — surface-attached microbial communities — can be 10–1,000-fold greater than in planktonic bacteria. Now, Graham Walker, George O'Toole and colleagues have identified a mutant of Pseudomonas aeruginosa that can form biofilms but is susceptible to antibiotics. The mutated gene encodes a glucosyltransferase that is involved in the synthesis of cyclic periplasmic glucans that can sequester antibiotics, which might account for biofilm antibiotic resistance.

Industrial microbiology

Innovative approach for improvement of an antibiotic-overproducing industrial strain of Streptomyces albus Tamehiro, N. et al. Appl. Environ. Microbiol. 69, 6412–6417 (2003)

Using a Streptomyces albus strain that produced industrial amounts (10 mg ml−1) of salinomycin, the authors introduced drug-resistance-producing mutations. Mutants with combined resistance to streptomycin, gentamicin and rifampin produced 2.3-fold more salinomycin then the parent strain.

Evolution

Evolution of genomic diversity and sex at extreme environments: fungal life under hypersaline Dead Sea stress Kis-Papo, T. et al. Proc. Natl Acad. Sci. USA 100, 14970–14975 (2003)

The Dead Sea has non-saline, saline and hypersaline microenvironments. Eviator Nevo and his team exploited this unique habitat and assessed the diversity of coding and non-coding sequences of the filamentous fungus Aspergillus versicolor from different niches by amplified-fragment length polymorphism (AFLP). Genomic diversity was not random, and positively correlated with increasing levels of ecological stress, but diversity was reduced in the most extreme conditions because only fit genotypes can survive. The proportion of sexual fungi correlated with the patterns of genetic diversity — studying micromycete fungi might help to unravel the answers to fundamental questions about evolution and sex.