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.     

Field and mesocosm trials on passive sampling for the study of adsorption and desorption behaviour of lipophilic toxins with a focus on OA and DTX1

It has been demonstrated that polymeric resins can be used as receiving phase in passive samplers designed for the detection of lipophilic marine toxins at sea and was referred to as solid phase adsorption toxin tracking (SPATT). The present study describes the uptake and desorption behaviour of the lipophilic marine toxins okadaic acid (OA) and dinophysistoxin-1 (DTX1) from Prorocentrum lima cultures by five styrene—divinylbenzene based polymeric resins Sepabeads^® SP850, Sepabeads^® SP825L, Amberlite^® XAD4, Dowex^® Optipore^® L-493 and Diaion^® HP-20. All resins accumulated OA and DTX1 from the P. lima culture with differences in adsorption rate and equilibrium rate. Following statistical evaluation, HP-20, SP850 and SP825L demonstrated similar adsorption rates. However, possibly due to its larger pore size, the HP-20 did not seem to reach equilibrium within 72 h exposure as opposed to the SP850 and SP825L. This was confirmed when the resins were immersed at sea for 1 week on the West Coast of Ireland. Furthermore, this work also presents a simple and efficient extraction method suitable to SPATT samplers exposed to artificial or natural culture media.     

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.     

Independence between modification of genetic position effects and formation of lampbrush loops by the Y chromosome of Drosophila hydei

Summary The phenotype of the variegation position effect white-mottled-2 in Drosophila hydei is modified by supernumerary Y chromosomes and by fractions thereof. Different translocated Y fragments have varying degrees of effectiveness in suppressing the mutant phenotype in the mottled eyes. In fragments derived from similar regions of the Y chromosome the suppressive ability is related to their cytological lengths. In contrast, fragments derived from distinctive regions of the Y chromosome differ markedly in their effectiveness, and these differences are not necessarily correlated with the cytological length. In particular, fragments of the distal region of Y^L are more effective in enhancing the wild phenotype than are proximal fragments of similar size.The mutation white-mottled-2 is accompanied by a complex rearrangement of the X chromosome. This inhibits crossing over between large regions of the X chromosome in structural heterozygotes; it causes also a delay of development and a considerable reduction of viability in homozygous females and hemizygous males. XO males are inviable. The inviability of these males is partially covered by Y fragments. With respect to viability, the fragments show similar regional differences in effectiveness as in the modification of the mottled phenotype.There is also a parental effect on the modulation of the white-mottled-2 phenotype.There is no correlation between the activity of Y chromosomal factors on spermiogenesis and the activity of Y factors on the modification of the variegation position effect. Suppression of Y chromosomal sites which normally unfold lampbrush loops during the spermatocyte stage and whose activity has previously been shown to be indispensible for normal differentiation of the male germ line cells does not result in any visible alterations of the effectiveness on the mottling. So there is obviously independence between these two different genetic activities of Y chromosomal factors.     

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.