Microarray analysis of a microbe–mineral interaction

The weathering of volcanic minerals makes a significant contribution to the global silicate weathering budget, influencing carbon dioxide drawdown and long‐term climate control. Basalt rocks may account for over 30% of the global carbon dioxide drawdown in silicate weathering. Micro‐organisms are known to play a role in rock weathering yet the genomics and genetics of biological rock weathering are unknown. We apply DNA microarray technology to determine putative genes involved in weathering using the heavy metal‐resistant organism, Cupriavidus metallidurans CH34; in particular we investigate the sequestering of iron. The results show that the bacterium does not depend on siderophores. Instead, the up‐regulation of porins and transporters which are employed concomitantly with genes associated with biofilm formation suggests that novel passive and active iron uptake systems are involved. We hypothesize that these mechanisms induce rock weathering by changes in chemical equilibrium at the microbe–mineral interface, reducing the saturation state of iron. We also demonstrate that low concentrations of metals in the basalt induce heavy metal‐resistant genes. Some of the earliest environments on the Earth were volcanic. Therefore, these results not only elucidate the mechanisms by which micro‐organisms might have sequestered nutrients on the early Earth but also provide an explanation for the evolution of multiple heavy metal resistance genes long before the creation of contaminated industrial biotopes by human activity.     

Neumann’s Warbler Hemitesia neumanni (Sylvioidea): the sole African member of a Palaeotropic Miocene avifauna

We present molecular evidence that Neumann’s Warbler Hemitesia neumanni is deeply nested within the Cettiidae. The species’ distribution in the Albertine Rift of East Africa is intriguing, as the family Cettiidae is principally an Asian radiation. This disjunct distribution could be a result of colonization of Africa by long‐distance dispersal, or the Cettiidae may at some point in the past have had a much larger geographical distribution that also covered parts of Africa.     

Degradation of Chitotetraose to Chitobiose in the Axenic Rape Rhizosphere

In the presence of intact roots of 2-week-old axenic rape seedlings,added N, N', N', N'-tetraacetylchitotetraose was degradedto N, N'-diacetylchitobiose during 48 h of incubation. Onlyminute amounts of monomer (N-acetyglucosamine) were formed fromadded chitotetraose or chitobiose. The addition of a purifiedchitin suspension caused no measurable formation of degradationproducts. The formation of chitobiose from added chitotetraose was linear,suggesting the action of a constitutive enzyme during the incubationperiod. Key words: Brassica napus (L.) cv. Brink, rhizosphere, N, N'-diacetylchitobiose, N,N',N',N', tetraacetylchitotetraose     

Rapid Sustainability Modeling for Raptors by Radiotagging and DNA-Fingerprinting

Abstract: Sustainable use of wildlife is crucial to ensuring persistence of natural resources. We used age-specific survival and breeding data to parameterize a demographic model for a harvested Kazakh saker falcon (Falco cherrug) population by radiotagging juveniles and estimating adult turnover with DNA-fingerprinting during 1993–1997. We gathered similar data during 1990–1998 to model populations of British buzzards (Buteo buteo), and during 1980–1998 to model populations of Swedish goshawks (Accipiter gentilis). Leg-bands and implanted microtransponders provided ways to test for bias and to estimate the harvest of sakers for falconry. Despite an estimated minimum first-year survival of only 23%, the observed productivity of 3.14 young per clutch would sustain a saker population (i.e., λ = 1) with a breeding rate (at laying) of only 0.63 for adults or with a residual juvenile yield of 37% if all adults breed. Higher first-year survival rates for goshawks and buzzards correlated with juvenile yields of up to 71%, but no more than half as many individuals if adults also were harvested. An annual population decline of 40% for sakers in southern Kazakhstan could be explained by observed productivity of only 0.71 young per clutch if there was also an estimated harvest of 55% of adults. This study shows that demographic models such as these can now be built rapidly if nestlings are fitted with reliable and safe radiotags and adult turnover is estimated from genetic analyses or other techniques.     

Genetic studies on resistance to clubroot in Brassica napus

The rate of softening of apples of the variety Spartan was reduced by addition of 6 or 8% CO₂ to a storage atmosphere of 2% O₂ at 1 -5 ^oC. This effect was observed in three seasons and in samples from five sources. Sensory assessments suggested that addition of carbon dioxide to the storage atmosphere had no adverse effect on eating quality. Storage in 2% O₂ at – 1 ^oC was as effective in maintaining flesh firmness as 8% CO₂+ 2%O₂ at 1–5 ^oC. Strategies for further reductions in firmness loss during storage of Spartan apples are discussed.