Acoustic communication at the water's edge: evolutionary insights from a mudskipper

Coupled behavioural observations and acoustical recordings of aggressive dyadic contests showed that the mudskipper Periophthalmodon septemradiatus communicates acoustically while out of water. An analysis of intraspecific variability showed that specific acoustic components may act as tags for individual recognition, further supporting the sounds' communicative value. A correlative analysis amongst acoustical properties and video-acoustical recordings in slow-motion supported first hypotheses on the emission mechanism. Acoustic transmission through the wet exposed substrate was also discussed. These observations were used to support an "exaptation hypothesis", i.e. the maintenance of key adaptations during the first stages of water-to-land vertebrate eco-evolutionary transitions (based on eco-evolutionary and palaeontological considerations), through a comparative bioacoustic analysis of aquatic and semiterrestrial gobiid taxa. In fact, a remarkable similarity was found between mudskipper vocalisations and those emitted by gobioids and other soniferous benthonic fishes.     

Characterizing associations and SNP-environment interactions for GWAS-identified prostate cancer risk markers--results from BPC3

Genome-wide association studies (GWAS) have identified multiple single nucleotide polymorphisms (SNPs) associated with prostate cancer risk. However, whether these associations can be consistently replicated, vary with disease aggressiveness (tumor stage and grade) and/or interact with non-genetic potential risk factors or other SNPs is unknown. We therefore genotyped 39 SNPs from regions identified by several prostate cancer GWAS in 10,501 prostate cancer cases and 10,831 controls from the NCI Breast and Prostate Cancer Cohort Consortium (BPC3). We replicated 36 out of 39 SNPs (P-values ranging from 0.01 to 10⁻²⁸). Two SNPs located near KLK3 associated with PSA levels showed differential association with Gleason grade (rs2735839, P = 0.0001 and rs266849, P = 0.0004; case-only test), where the alleles associated with decreasing PSA levels were inversely associated with low-grade (as defined by Gleason grade <8) tumors but positively associated with high-grade tumors. No other SNP showed differential associations according to disease stage or grade. We observed no effect modification by SNP for association with age at diagnosis, family history of prostate cancer, diabetes, BMI, height, smoking or alcohol intake. Moreover, we found no evidence of pair-wise SNP-SNP interactions. While these SNPs represent new independent risk factors for prostate cancer, we saw little evidence for effect modification by other SNPs or by the environmental factors examined.     

Efficient detection of proteins retro-translocated from the ER to the cytosol by in vivo biotinylation

Retro-translocation from the ER to the cytosol of proteins within the secretory pathway takes place on misfolded molecules that are targeted for degradation by the cytosolically located 26S proteasome complex. Retro-translocation occurs also for other proteins (such as calreticulin) that, despite being synthesized and transported to the ER, are in part dislocated to the cytosol. We have taken advantage of the E. coli derived biotin-ligase (BirA) expressed in the cytosol of mammalian cells to specifically biotin-label in vivo proteins within the secretory pathway that undergo retro-translocation. We validated the method using four different proteins that are known to undergo retro-translocation upon different conditions: the human trans-membrane protein MHC class-I α chain (MHC-Iα), the Null Hong Kong mutant of the secretory α1 anti-trypsin (NHK-α1AT), the immunoglobulin heavy chain (HC) and the ER chaperone calreticulin (Crt). We observed specific mono-biotinylation of cytosolically dislocated molecules, resulting in a novel, reliable way of determining the extent of retro-translocation.     

Severe and persistent depletion of circulating plasmacytoid dendritic cells in patients with 2009 pandemic H1N1 infection

Background

Dysregulation of host immune responses plays a critical role in the pathogenesis of severe 2009 pandemic H1N1 infection. Whether H1N1 virus could escape innate immune defense in vivo remains to be investigated. The aim of this study was to evaluate the pattern of innate immune response during human 2009 H1N1 infection. We performed the enumeration of circulating myeloid dendritic cells (mDC) and plasmacytoid DC (pDC) in blood from patients with H1N1 pneumonia shortly after the onset of symptoms and during follow-up at different intervals of time. The analysis of CD4 and CD8 count, CD38 T-cell activation marker and serum cytokine/chemokine plasma levels was also done.

Methodology/Principal Findings

Blood samples were collected from 13 hospitalized patients with confirmed H1N1-related pneumonia at time of admission and at weeks 1, 4, and 16 of follow-up. 13 healthy donors were enrolled as controls. In the acute phase of the disease, H1N1-infected patients exhibited a significant depletion in both circulating pDC and mDC in conjunction with a decrease of CD4 and CD8 T cell count. In addition, we found plasmatic hyperproduction of IP-10 and RANTES, whereas increase in T-cell immune activation was found at all time points. When we assessed the changes in DC count over time, we observed a progressive normalization of mDC number. On the contrary, H1N1-infected patients did not achieve a complete recovery of pDC count as values remained lower than healthy controls even after 16 weeks of follow-up.

Conclusions

H1N1 disease is associated with a profound depletion of DC subsets. The persistence of pDC deficit for several weeks after disease recovery could be due to H1N1 virus itself or to a preexisting impairment of innate immunity.     

Mechanisms of endothelial dysfunction with development of type 1 diabetes mellitus: role of insulin and C-peptide

Complications associated with insulin-dependent diabetes mellitus (type-1diabetes) primarily represent vascular dysfunction that has its origin in the endothelium. While many of the vascular changes are more accountable in the late stages of type-1diabetes, changes that occur in the early or initial functional stages of this disease may precipitate these later complications. The early stages of type-1diabetes are characterized by a diminished production of both insulin and C-peptide with a significant hyperglycemia. During the last decade numerous speculations and theories have been developed to try to explain the mechanisms responsible for the selective changes in vascular reactivity and/or tone and the vascular permeability changes that characterize the development of type-1diabetes. Much of this research has suggested that hyperglycemia and/or the lack of insulin may mediate the observed functional changes in both endothelial cells and vascular smooth muscle. Recent studies suggest several possible mechanisms that might be involved in the observed decreases in vascular nitric oxide (NO) availability with the development of type-1 diabetes. In addition more recent studies have indicated a direct role for both endogenous insulin and C-peptide in the amelioration of the observed endothelial dysfunction. These results suggest a synergistic action between insulin and C-peptide that facilitates increase NO availability and may suggest new clinical treatment modalities for type-1 diabetes mellitus.     

Bone medullary arterioles from ovariectomized rats have smaller baseline diameters but normal eNOS expression and NO-mediated dilation

This study was designed to test the hypothesis that endogenous estrogens decrease the expression of endothelial nitric oxide synthase (eNOS) in resistance-size bone arterioles, thereby reducing endothelium-dependent vasodilator function. Sexually mature female rats were ovariectomized to reduce endogenous estrogens. Age-matched female rats served as controls. Seven to ten days after ovariectomy, bone marrow tissue was collected from the femoral canal. Immuno-histochemistry was performed to detect expression of estrogen receptors, alpha and beta and eNOS. eNOS protein content in medullary bone arterioles was compared using Western blot analysis. Endothelial cell function was assessed by quantitating the dilation of isolated, pressurized bone arterioles in response to acetylcholine. The results indicate that the endothelium of bone arterioles from ovariectomized and control rats express ER-alpha, ER-beta and eNOS. eNOS protein content in the two groups of arterioles did not differ. However, the baseline diameter of arterioles from ovariectomized rats (63+/-4 microm) was significantly smaller than the diameter of arterioles from control rats (75+/-3 microm, p<0.05). The two groups of arterioles dilated equally in response to acetylcholine. L-NAME, an inhibitor of eNOS, almost completely abolished the dilator responses to acetylcholine, but not to sodium nitroprusside. L-Arginine restored acetylcholine-induced dilation after L-NAME treatment. Thus, arteriole dilation to acetylcholine appears to be mediated almost exclusively by NO. The smaller diameter of arterioles from ovariectomized rats suggests that endogenous estrogens exert a significant dilator influence on bone arterioles. However, the dilator influence does not appear to be mediated by an increase in eNOS expression or enhanced NO-dependent vasodilation. These results indicate that estrogens do not decrease eNOS expression or diminish NO-mediated dilation of bone medullary arterioles.     

Substrate-induced conformational changes of the mitochondrial oxoglutarate carrier: a spectroscopic and molecular modelling study

The structural and dynamic properties of the oxoglutarate carrier were investigated by introducing a single tryptophan in the Trp-devoid carrier in position 184, 190 or 199 and by monitoring the fluorescence spectra in the presence and absence of the substrate oxoglutarate. In the absence of substrate, the emission maxima of Arg190Trp, Cys184Trp and Leu199Trp are centered at 342, 345 and 348 nm, respectively, indicating that these residues have an increasing degree of solvent exposure. The emission intensity of the Arg190Trp and Cys184Trp mutants is higher than that of Leu199Trp. Addition of substrate increases the emission intensity of Leu199Trp, but not that of Cys184Trp and Arg190Trp. A 3D model of the oxoglutarate carrier was built using the structure of the ADP/ATP carrier as a template and was validated with the experimental results available in the literature. The model identifies Lys122 as the most likely candidate for the quenching of Trp199. Consistently, the double mutant Lys122Ala-Leu199Trp exhibits a higher emission intensity than Leu199Trp and does not display further fluorescence enhancement in response to substrate addition. Substitution of Lys122 with Cys and evaluation of its reactivity with a sulphydryl reagent in the presence and absence of substrate confirms that residue 122 is masked by the substrate, likely through a substrate-induced conformational change.     

5-Alkyl-2-alkylamino-6-(2,6-difluorophenylalkyl)-3,4-dihydropyrimidin-4(3H)-ones, a new series of potent, broad-spectrum non-nucleoside reverse transcriptase inhibitors belonging to the DABO family

2-Alkylamino-6-[1-(2,6-difluorophenyl)alkyl]-3,4-dihydro-5-alkylpyrimidin-4(3H)-ones (F(2)-NH-DABOs) 4, 5 belonging to the dihydro-alkoxy-benzyl-oxopyrimidine (DABO) family and bearing different alkyl- and arylamino side chains at the C(2)-position of the pyrimidine ring were designed as active against wild type (wt) human immunodeficiency virus type 1 (HIV-1) and some relevant HIV-1 mutants. Biological evaluation indicated the importance of the further anchor point of compounds 4, 5 into the non-nucleoside binding site (NNBS): newly synthesized compounds were highly active against both wild type and the Y181C HIV-1 strains. In anti-wt HIV-1 assay the potency of amino derivatives did not depend on the size or shape of the C(2)-amino side chain, but it associated with the presence of one or two methyl groups (one at the pyrimidine C(5)-position and the other at the benzylic carbon), being thymine, alpha-methyluracil or alpha-methylthymine derivatives almost equally active in reducing wt HIV-1-induced cytopathogenicity in MT-4 cells. Against the Y181C mutant strain, 2,6-difluorobenzyl-alpha-methylthymine derivatives 4d, 5h'-n' showed the highest potency and selectivity among tested compounds, both a properly sized C(2)-NH side chain and the presence of two methyl groups (at C(5) and benzylic positions) being crucial for high antiviral action.