Testing predictions of beetle community patterns derived empirically using remote sensing

Patterns generated from ecological surveys are rarely tested in similar habitats to assess the accuracy of predictions. Testing empirically derived predictions provides a strong tool for establishing the consistency of general patterns in ecology. We test the consistency of beetle community associations with habitat complexity in open canopy forests and make both community and morphospecies-level comparisons with results from a previous study. We use Normalized Difference Vegetation Indices (NDVIs) from remote sensing as a surrogate for habitat complexity. The positive relationships between NDVIs and site-based beetle species richness and abundance were consistent in open canopy forests both south and north of Sydney, Australia. NDVIs were also useful for predicting differences in beetle composition in open canopy forests. Taxon-specific responses to NDVI differences in 'southern forests' were very similar to responses in 'northern forests', most likely reflecting beetle trophic roles. This study shows that NDVIs can be used as rapid biodiversity indicators, when integrated with identified faunal responses to vegetation structure, provided that the lower vegetation strata may be measured by remote sensing.     

Generation of New Hairless Alleles by Genomic Engineering at the Hairless Locus in Drosophila melanogaster

Hairless (H) is the major antagonist within the Notch signalling pathway of Drosophila melanogaster. By binding to Suppressor of Hairless [Su(H)] and two co-repressors, H induces silencing of Notch target genes in the absence of Notch signals. We have applied genomic engineering to create several new H alleles. To this end the endogenous H locus was replaced with an attP site by homologous recombination, serving as a landing platform for subsequent site directed integration of different H constructs. This way we generated a complete H knock out allele H ^attP, reintroduced a wild type H genomic and a cDNA-construct (H ^gwt, H ^cwt) as well as two constructs encoding H proteins defective of Su(H) binding (H ^LD, H ^iD). Phenotypes regarding viability, bristle and wing development were recorded, and the expression of Notch target genes wingless and cut was analysed in mutant wing discs or in mutant cell clones. Moreover, genetic interactions with Notch (N ⁵⁴¹⁹) and Delta (Dl ^B2) mutants were addressed. Overall, phenotypes were largely as expected: both H ^LD and H ^iD were similar to the H ^attP null allele, indicating that most of H activity requires the binding of Su(H). Both rescue constructs H ^gwt and H ^cwt were homozygous viable without phenotype. Unexpectedly, the hemizygous condition uncovered that they were not identical to the wild type allele: notably H ^cwt showed a markedly reduced activity, suggesting the presence of as yet unidentified regulatory or stabilizing elements in untranslated regions of the H gene. Interestingly, H ^gwt homozygous cells expressed higher levels of H protein, perhaps unravelling gene-by-environment interactions.     

New Approach to Develop Optimized Sunscreens that Enable Cutaneous Vitamin D Formation with Minimal Erythema Risk

Sunscreens protect the skin against erythemal radiation (E_er). But at the same time they reduce the effective radiation dose (E_VD) responsible for the formation of previtamin D in the skin. The paper describes a calculation method for optimizing the ratio E_VD/E_er behind sunscreens e.g. with SPF 5, 15 and 30 respectively. Taking into account that a majority of people in industrialized countries suffer from a shortage in vitamin D even in summer time, the ratio E_vd/E_er is a new and important criterion for the quality of sunscreens. Furthermore the exposure time t_vd needed per day for forming the equivalent of the recommended amount of 2000 IU of vitamin D per day for skin type 2 is estimated when sunscreens with different filter compositions are used. In vitro experiments show a significant increase of the conversion of 7-dehydrocholesterol (7-DHC) to previtamin D when exposed to artificial solar radiation behind an experimental sunscreen optimized for previtamin D production compared to a commercial sunscreen having the same SPF.     

Two distinct proteolytic systems responsible for glucose-induced degradation of fructose-1,6-bisphosphatase and the Gal2p transporter in the yeast Saccharomyces cerevisiae share the same protein components of the glucose signaling pathway.

Addition of glucose to Saccharomyces cerevisiae inactivates the galactose transporter Gal2p and fructose-1,6-bisphosphatase (FBPase) by a mechanism called glucose- or catabolite-induced inactivation, which ultimately results in a degradation of both proteins. It is well established, however, that glucose induces internalization of Gal2p into the endocytotic pathway and its subsequent proteolysis in the vacuole, whereas FBPase is targeted to the 26 S proteasome for proteolysis under similar inactivation conditions. Here we report that two distinct proteolytic systems responsible for specific degradation of two conditionally short-lived protein targets, Gal2p and FBPase, utilize most (if not all) protein components of the same glucose sensing (signaling) pathway. Indeed, initiation of Gal2p and FBPase proteolysis appears to require rapid transport of those substrates of the Hxt transporters that are at least partially metabolized by hexokinase Hxk2p. Also, maltose transported via the maltose-specific transporter(s) generates an appropriate signal that culminates in the degradation of both proteins. In addition, Grr1p and Reg1p were found to play a role in transduction of the glucose signal for glucose-induced proteolysis of Gal2p and FBPase. Thus, one signaling pathway initiates two different proteolytic mechanisms of catabolite degradation, proteasomal proteolysis and endocytosis followed by lysosomal proteolysis.     

Methanogenesis in a saltern in the Bretagne (France)

Abstract Salterns in the Bretagne (France), exhibiting different stages of salinity of 5% to 33% evolved up to 0.7 mmol methane per m² per day. Methane concentrations of up to 0.4 mM were found. High methane evolution rates and increased methane concetration were restricted to basins of up to 7% and more than 15% salinity, and to the upper 10 cm of the sediments, where high sulfate concentrations (50 to 100 mM) occurred as well. Basins of 10–15% salinity exhibited only low methane evolution rates (less than 0.05 mmol methane per m² per day) and low methane concentrations (less than 0.02 mM). Gas bubbles arising during times of increased photosynthetic activity from the microbial mats covering the sediments of the saltern basins contained up to 2% methane. Addition of methylated amines and methanol, but not of H₂/CO₂, formate or acetate, to sediments slurries from basins of up to 12% salinity resulted in a rapid enrichment of methanogenic populations. Enriched methanogenic bacteria did not grow at salinities exceeding 15% or temperatures exceeding 45°C, and showed characteristics similar to those documented for Methanococcus halophilus and strain SF1 (DSM 3243). No enrichments were obtained from basins of more than 20% salinity in spite of methane being produced and evolved from those basins.