Topography strongly affects atmospheric deposition and canopy exchange processes in different types of wet lowland rainforest,Southwest Costa Rica

Bulk precipitation and throughfall were collected in a wet lowland rainforest in SW Costa Rica on an event basis to allow modelling the contributions of dry deposition and canopy exchange to nutrient inputs and internal cycling of nutrients. Estimates based on bulk precipitation underestimated total atmospheric deposition to tropical rainforests by up to 10-fold ignoring the contributions of dry deposition. Canopy exchange contributed most of the aboveground inputs to the forest soil of Na⁺, about half for K⁺, 10% for P and Mg²⁺ and negligible for N, C and other elements. Tree species composition did not account for the differences found in net throughfall between forest sites, and vegetation structure (plant area index) had only a small effect on net throughfall. Forest regrowth affected net throughfall through reduced soil fertility and differences in leaf traits. Topography most significantly affected net throughfall via increased dry deposition at sites of higher elevation and via soil fertility and increased canopy exchange at down slope sites.     

Somatostatin receptor interacting protein defines a novel family of multidomain proteins present in human and rodent brain.

By using the yeast two-hybrid system we identified a novel protein from the human brain interacting with the C terminus of somatostatin receptor subtype 2. This protein termed somatostatin receptor interacting protein is characterized by a novel domain structure, consisting of six N-terminal ankyrin repeats followed by SH3 and PDZ domains, several proline-rich regions, and a C-terminal sterile alpha motif. It consists of 2185 amino acid residues encoded by a 9-kilobase pair mRNA; several splice variants have been detected in human and rat cDNA libraries. Sequence comparison suggests that the novel multidomain protein, together with cortactin-binding protein, forms a family of cytoskeletal anchoring proteins. Fractionation of rat brain membranes indicated that somatostatin receptor interacting protein is enriched in the postsynaptic density fraction. The interaction of somatostatin receptor subtype 2 with its interacting protein was verified by overlay assays and coimmunoprecipitation experiments from transfected human embryonic kidney cells. Somatostatin receptor subtype 2 and the interacting protein display a striking overlap of their expression patterns in the rat brain. Interestingly, in the hippocampus the mRNA for somatostatin receptor interacting protein was not confined to the cell bodies but was also observed in the molecular layer, suggesting a dendritic localization of this mRNA.     

Identifying essential genes in bacterial metabolic networks with machine learning methods

Background  

Identifying essential genes in bacteria supports to identify potential drug targets and an understanding of minimal requirements for a synthetic cell. However, experimentally assaying the essentiality of their coding genes is resource intensive and not feasible for all bacterial organisms, in particular if they are infective.     

State-of-the art data normalization methods improve NMR-based metabolomic analysis

Extracting biomedical information from large metabolomic datasets by multivariate data analysis is of considerable complexity. Common challenges include among others screening for differentially produced metabolites, estimation of fold changes, and sample classification. Prior to these analysis steps, it is important to minimize contributions from unwanted biases and experimental variance. This is the goal of data preprocessing. In this work, different data normalization methods were compared systematically employing two different datasets generated by means of nuclear magnetic resonance (NMR) spectroscopy. To this end, two different types of normalization methods were used, one aiming to remove unwanted sample-to-sample variation while the other adjusts the variance of the different metabolites by variable scaling and variance stabilization methods. The impact of all methods tested on sample classification was evaluated on urinary NMR fingerprints obtained from healthy volunteers and patients suffering from autosomal polycystic kidney disease (ADPKD). Performance in terms of screening for differentially produced metabolites was investigated on a dataset following a Latin-square design, where varied amounts of 8 different metabolites were spiked into a human urine matrix while keeping the total spike-in amount constant. In addition, specific tests were conducted to systematically investigate the influence of the different preprocessing methods on the structure of the analyzed data. In conclusion, preprocessing methods originally developed for DNA microarray analysis, in particular, Quantile and Cubic-Spline Normalization, performed best in reducing bias, accurately detecting fold changes, and classifying samples.

     

Toll-like receptor 4 deficiency: Smaller infarcts,but nogain in function

Backgound  

It has been reported that Toll-like receptor 4 (TLR4) deficiency reduces infarct size after myocardial ischemia/reperfusion (MI/R). However, measurement of MI/R injury was limited and did not include cardiac function. In a chronic closed-chest model we assessed whether cardiac function is preserved in TLR4-deficient mice (C3H/HeJ) following MI/R, and whether myocardial and systemic cytokine expression differed compared to wild type (WT).     

Analytik Atypischer Fettsäuren in biologischen Matrizes

By combined application of chemical pretreatments, capillary gas-chromatography and mass spectrometry it was possible to enlighten the structure of atypical fatty acids with hydroxy groups and cyclopropane rings under the use of only a few of reference substances. The direct alkaline saponification of the sample with liberation of fatty acids and following methylation with boron trifluoride/methanol or diazomethane was proved to be the best method regarding to precision and speed of the sample cleanup.     

Conserved exon-intron organization in two different caerulein precursor genes of Xenopus laevis. Additional detection of an exon potentially coding for a new peptide

From a genomic library of Xenopus laevis, two genes coding for different preprocaeruleins have been isolated and sequenced. These correspond to the type I and type III precursors analyzed previously at the cDNA level [Richter, K., Egger, R. and Kreil, G. (1986) J. Biol. Chem. 261, 3676-3680]. The type III gene comprises eight exons; the type I apparently contains eight exons as well, of which six have been sequenced. The genetic information for the dekapeptide caerulein is present on small exons of 45 base pairs. The two genes are highly homologous in their 5'-flanking region, the exon/intron boundaries, and long stretches of intron sequences. A possible scheme for the evolution of this small family of genes through exon and gene duplications is presented. In the type I gene, in place of one of the caerulein exons, a potential exon with conserved splice sites was discovered. If expressed in some frog cells, this exon would code for a new peptide 60% homologous to caerulein.     

A portable,adjustable finger printing stand

A lightweight finger printing stand is described which can be adjusted to the proper printing height. Based upon experience printing over 1,100 subjects, 12 advantages of using the stand are suggested.