Leaf hydrocarbons of Phacelia species (hydrophyllaceae)

Whole leaf hydrocarbons of six species of Phacelia were investigated for their variability among natural Californian populations, and for adaptive     

A facile method to prepare C-terminal fluorescently labelled peptides by an Fmoc strategy

Summary Spectrophotometric peptide probes, derivatized at the C-terminus, are conveniently prepared by means of an Fmoc solid-phase strategy. Using a resin such as Sasrin, the fully protected peptide can be cleaved from the resin with hydrazine, yielding the protected peptide-hydrazide which is subsequently oxidized to the azide. An amino-containing chromophore or fluorophore such as 5-[(2-aminoethyl)-amino]-naphthalene sulfonic acid (EDANS) can be coupled directly to this activated carboxyl group. This allows for specific placement of the fluorophore at the C-terminal carboxyl group in the presence of trifunctional amino acids.     

Grazing in remnant wetland habitats in an arid region: direct and indirect effects on two specialist bird species

Capsule: Grazing by livestock can have complex effects on drivers of population change in the Clamorous Reed Warbler Acrocephalus stentoreus and Dead Sea Sparrow Passer moabiticus.

Aims: To investigate the effect on two specialist bird species on wetland degradation in the Jordan Valley.

Methods: The direct and indirect effects of grazing on the probability of occurrences of two specialist bird species, Clamorous Reed Warbler A. stentoreus and Dead Sea Sparrow P. moabiticus, were analysed during the breeding season at the patch scale, using path analysis.

Results: Tamarix shrub density was a strong predictor for the presence of both species. Grazing had a negative total effect on both; a significant indirect effect on Dead Sea Sparrow via its impact on the mean height of shrubs, and a significant, negative indirect effect on Clamorous Reed Warbler by reducing reed cover. Intensive grazing and browsing by livestock including goats, sheep and camels, apparently had a negative effect on the overall density of native Tamarix shrubs, while promoting encroachment by invasive Prosopis juliflora.

Conclusion: This may be part of a long-term cascade leading to an ecological transition and loss of important wetland habitats in the arid Jordan Valley.     

Promises and pitfalls of using high‐throughput sequencing for diet analysis

The application of high‐throughput sequencing‐based approaches to DNA extracted from environmental samples such as gut contents and faeces has become a popular tool for studying dietary habits of animals. Due to the high resolution and prey detection capacity they provide, both metabarcoding and shotgun sequencing are increasingly used to address ecological questions grounded in dietary relationships. Despite their great promise in this context, recent research has unveiled how a wealth of biological (related to the study system) and technical (related to the methodology) factors can distort the signal of taxonomic composition and diversity. Here, we review these studies in the light of high‐throughput sequencing‐based assessment of trophic interactions. We address how the study design can account for distortion factors, and how acknowledging limitations and biases inherent to sequencing‐based diet analyses are essential for obtaining reliable results, thus drawing appropriate conclusions. Furthermore, we suggest strategies to minimize the effect of distortion factors, measures to increase reproducibility, replicability and comparability of studies, and options to scale up DNA sequencing‐based diet analyses. In doing so, we aim to aid end‐users in designing reliable diet studies by informing them about the complexity and limitations of DNA sequencing‐based diet analyses, and encourage researchers to create and improve tools that will eventually drive this field to its maturity.     

Up-regulation of expression of translation factors – a novel molecular mechanism for cadmium carcinogenesis

The molecular mechanisms potentially responsible for cadmium carcinogenesis were investigated by differential gene expression analysis of Balb/c-3T3 cells morphologically transformed with cadmium chloride. Differential display analysis of gene expression revealed overexpression of mouse Translation Initiation Factor 3 (TIF3; GenBank Accession Number AF 271072) and Translation Elongation Factor-1delta (TEF-1delta; GenBank Accession Number AF 304351) in the transformed cells compared with the control cells. The full length cDNAs for TIF3 and TEF-1delta were cloned and sequenced. Transfection of mammalian cells with an expression vector containing either TIF3 or TEF-1delta cDNA resulted in overexpression of the encoded protein. Overexpression of the cDNA-encoded TIF3 and TEF-1delta proteins in NIH3T3 cells was oncogenic as evidenced by the appearance of transformed foci capable of anchorage-independent growth on soft agar and tumorigenesis in nude mouse. Blocking the translation of TIF3 and TEF-1delta proteins using the corresponding antisense mRNA resulted in a significant reversal of the oncogenic potential of cadmium transformed Balb/c-3T3 cells as evidenced from the suppression of anchorage-independent growth on soft agar and diminished tumorigenesis in nude mouse. These findings demonstrate that the up-regulation of expression of TIF3 and TEF-1delta is a novel molecular mechanism responsible, at least in part, for cadmium carcinogenesis.     

Rho kinase is required for CCR7-mediated polarization and chemotaxis of T lymphocytes

A chemokine receptor, CXCR4, and its endogenous ligand, stromal cell-derived factor-1 (SDF-1), have been recognized to be involved in the metastasis of several types of cancers. T140 analogs are peptidic CXCR4 antagonists composed of 14 amino acid residues that were previously developed as anti-HIV agents having inhibitory activity against HIV-entry through its co-receptor, CXCR4. Herein, we report that these compounds effectively inhibited SDF-1-induced migration of human breast cancer cells (MDA-MB-231), human leukemia T cells (Sup-T1) and human umbilical vein endothelial cells at concentrations of 10–100 nM in vitro. Furthermore, slow release administration by subcutaneous injection using an Alzet osmotic pump of a potent and bio-stable T140 analog, 4F-benzoyl-TN14003, gave a partial, but statistically significant (P≤0.05 (t-test)) reduction in pulmonary metastasis of MDA-MB-231 in SCID mice, even though no attempt was made to inhibit other important targets such as CCR7. These results suggest that T140 analogs have potential use for cancer therapy, and that small molecular CXCR4 antagonists could potentially replace neutralizing antibodies as anti-metastatic agents for breast cancer.     

D-Peptides as inhibitors of the DnaK/DnaJ/GrpE chaperone system

DnaK, a Hsp70 homolog of Escherichia coli, together with its co-chaperones DnaJ and GrpE protects denatured proteins from aggregation and promotes their refolding by an ATP-consuming mechanism. DnaJ not only stimulates the gamma-phosphate cleavage of DnaK-bound ATP but also binds polypeptide substrates on its own. Unfolded polypeptides, such as denatured luciferase, thus form ternary complexes with DnaJ and DnaK. A previous study has shown that d-peptides compete with l-peptides for the same binding site in DnaJ but do not bind to DnaK (Feifel, B., Sch?nfeld, H.-J., and Christen, P. (1998) J. Biol. Chem. 273, 11999-12002). Here we report that d-peptides efficiently inhibit the refolding of denatured luciferase by the DnaK/DnaJ/GrpE chaperone system (EC50 = 1-2 microM). The inhibition of the chaperone action is due to the binding of d-peptide to DnaJ (Kd = 1-2 microM), which seems to preclude DnaJ from forming ternary (ATP.DnaK)m.substrate.DnaJn complexes. Apparently, simultaneous binding of DnaJ and DnaK to one and the same target polypeptide is essential for effective chaperone action.     

Stratification of solids,nitrogen and phosphorus in swine manure in deep pits under slatted floors

Manure slurries stored in pits under slatted floors of both finishing and nursery barns were sampled at four different depths to study stratifications of total solids (TS) and nutrients (nitrogen and phosphorus), and to determine the relationship between the stratification of TS and nutrients. The results obtained can be used to improve the management and handling of swine manure in the under-slat storage pits. A management scheme that can be adopted for both the finishing and the nursery barns' pits is the layer-by-layer harvesting of the manure. The thinner manure, which is lower in nutrients, can be spread on land near the production units in larger volumes or it may pumped to land remote from the production units without causing many clogging problems. The thicker manure, higher in nutrients, can be transported to land further away and spread in smaller volumes. The TS content of each stratum can be used to accurately estimate the nitrogen and phosphorus levels in the respective strata so that application rates can easily be adjusted accordingly during the time of land application.     

Changes in Saccharide Metabolism Induced by Infection of Camellia Sinensis by Exobasidium Vexans

Changes in saccharide contents of tea leaves during infection with blister blight fungus Exobasidium vexans Masse was studied. Saccharose and glucose contents decreased in the blistered portions when compared to the normal regions until sporulation and remained constant during the entire period of sporulation. Fructose content increased abruptly during the initiation of sporulation and remained constant up to the end of sporulation in both blistered and non-blistered regions. Starch content continuously decreased in the blistered region. Peroxidase activity was highly enhanced during the final stages of leaf senescence. The activity of acid invertase was inversely proportional to the starch content and closely related to the changes in the saccharose and glucose contents. Protein and chlorophyll contents gradually decreased in the blistered regions. This revised version was published online in July 2006 with corrections to the Cover Date.