Low codon bias and high rates of synonymous substitution in Drosophila hydei and D. melanogaster histone genes

We have evaluated codon usage bias in Drosophila histone genes and have obtained the nucleotide sequence of a 5,161-bp D. hydei histone gene repeat unit. This repeat contains genes for all five histone proteins (H1, H2a, H2b, H3, and H4) and differs from the previously reported one by a second EcoRI site. These D. hydei repeats have been aligned to each other and to the 5.0-kb (i.e., long) and 4.8-kb (i.e., short) histone repeat types from D. melanogaster. In each species, base composition at synonymous sites is similar to the average genomic composition and approaches that in the small intergenic spacers of the histone gene repeats. Accumulation of synonymous changes at synonymous sites after the species diverged is quite high. Both of these features are consistent with the relatively low codon usage bias observed in these genes when compared with other Drosophila genes. Thus, the generalization that abundantly expressed genes in Drosophila have high codon bias and low rates of silent substitution does not hold for the histone genes.      

Essential role for neutrophil recruitment to the liver in concanavalin A-induced hepatitis

Leukocyte infiltration into the liver is paramount to the development of liver injury in hepatitis. Hepatitis occurring after the administration of Con A in mice is felt to be a T lymphocyte-mediated disease. In this study, we report that neutrophils are the key initiators of lymphocyte recruitment and liver injury caused by Con A. The objectives of this study were to investigate the involvement of neutrophils in Con A-induced hepatitis in vivo via intravital microscopy. After Con A administration, we observed a significant increase in leukocyte rolling flux, a decrease in rolling velocity, and an increase in leukocyte adhesion to the hepatic microvasculature. Fluorescence microscopy identified that within 4 h of Con A administration only a minority of the recruited leukocytes were T lymphocytes. Furthermore, immunohistochemistry showed a significant increase in neutrophils recruited to the liver post-Con A treatment in association with liver cell damage, as reflected by elevated serum alanine aminotransferase levels. Using flow cytometry, we observed that Con A could bind directly to neutrophils, which resulted in a shedding of L-selectin, an increase in beta(2)-integrin expression, and the production of reactive oxidants. Following neutrophil depletion, a significant inhibition of Con A-induced CD4+ T lymphocyte recruitment to the liver resulted and complete reduction in hepatic injury, as assessed by serum alanine aminotransferase levels. In summary, the present data support the concept that neutrophils play an important and previously unrecognized role in governing Con A-induced CD4+ T cell recruitment to the liver and the subsequent development of hepatitis.     

A requirement for microglial TLR4 in leukocyte recruitment into brain in response to lipopolysaccharide

To study the mechanisms involved in leukocyte recruitment induced by local bacterial infection within the CNS, we used intravital microscopy to visualize the interaction between leukocytes and the microvasculature in the brain. First, we showed that intracerebroventricular injection of LPS could cause significant rolling and adhesion of leukocytes in the brain postcapillary venules of wild-type mice, while negligible recruitment was observed in TLR4-deficient C57BL/10ScCr mice and CD14 knockout mice, suggesting recruitment is mediated by TLR4/CD14-bearing cells. Moreover, we observed reduced but not complete inhibition of recruitment in MyD88 knockout mice, indicating both MyD88-dependent and -independent pathways are involved. The leukocyte recruitment responses in chimeric mice with TLR4-positive microglia and endothelium, but TLR4-negative leukocytes, were comparable to normal wild-type mice, suggesting either endothelium or microglia play a crucial role in the induction of leukocyte recruitment. LPS injection induced both microglial and endothelial activation in the CNS. Furthermore, minocycline, an effective inhibitor of microglial activation, completely blocked the rolling and adhesion of leukocytes in the brain and blocked TNF-alpha production in response to LPS in vivo. Minocycline did not affect activation of endothelium by LPS in vitro. TNFR p55/p75 double knockout mice also exhibited significant reductions in both rolling and adhesion in response to LPS, indicating TNF-alpha signaling is critical for the leukocyte recruitment. Our results identify a TLR4 detection system within the blood-brain barrier. The microglia play the role of sentinel cells detecting LPS thereby inducing endothelial activation and leading to efficient leukocyte recruitment to the CNS.     

Suicidal process,suicidal communication and psychosocial situation of young suicide attempters in a rural Vietnamese community

The study aimed to explore the suicidal process, suicidal communication and psychosocial situation of young suicide attempters in a rural community in Hanoi, Vietnam. Semi-structured interviews were conducted, in a community setting, with 19 suicide attempters aged 15-24 who had been consecutively hospitalized in an intensive care unit. In 12 of 19 cases, the first pressing, distinct and constant suicidal thoughts appeared less than one day before the suicide attempt in question. However, distress and mild, fleeting suicidal thoughts had been present up to six months before the suicide attempt in 16 cases. Five respondents had a suicide plan one to three days before attempting suicide. Altogether, 13 engaged in some form of suicidal communication before their attempt. This communication was, however, difficult for outsiders to interpret. Twelve of the respondents were victims of regular physical abuse and 16 had suffered psychological violence for at least one year before attempting suicide. Eighteen of the respondents used pesticides or raticides in their suicide attempts. None sought advice or consultation in the community despite long-standing psychosocial problems. The strategy of reducing the availability of suicide means (e.g., pesticides or raticides) in Asian countries should be complemented with a long-term suicide-preventive strategy that targets school dropouts and domestic violence, and promotes coping abilities and communication about psychological and social problems as well as recognition of signs of distress and suicidal communication.     

Proof-of-concept human laboratory study for protracted abstinence in alcohol dependence: effects of gabapentin

There is a need for safe medications that can effectively support recovery by treating symptoms of protracted abstinence that may precipitate relapse in alcoholics, e.g. craving and disturbances in sleep and mood. This proof-of-concept study reports on the effectiveness of gabapentin 1200 mg for attenuating these symptoms in a non-treatment-seeking sample of cue-reactive, alcohol-dependent individuals. Subjects were 33 paid volunteers with current Diagnostic and Statistical Manual of Mental Disorders-IV alcohol dependence and a strength of craving rating 1 SD or greater for alcohol than water cues. Subjects were randomly assigned to gabapentin or placebo for 1 week and then participated in a within-subjects trial where each was exposed to standardized sets of pleasant, neutral and unpleasant visual stimuli followed by alcohol or water cues. Gabapentin was associated with significantly greater reductions than placebo on several measures of subjective craving for alcohol as well as for affectively evoked craving. Gabapentin was also associated with significant improvement on several measures of sleep quality. Side effects were minimal, and gabapentin effects were not found to resemble any major classes of abused drugs. Results suggest that gabapentin may be effective for treating the protracted abstinence phase in alcohol dependence and that a randomized clinical trial would be an appropriate next step. The study also suggests the value of cue-reactivity studies as proof-of-concept screens for potential antirelapse drugs.     

A recently silenced, duplicate PgiC locus in Clarkia

Previous electrophoretic analysis showed that 17 diploid species of the wildflower Clarkia (Onagraceae) have two cytosolic isozymes of phosphoglucose isomerase (PGIC; EC 5.3.1.9), whereas 15 other diploid species have a single PGIC. Molecular studies revealed that the two isozymes in the former species are encoded by duplicate genes, PgiC1 and PgiC2, whereas the single isozyme in the latter is always encoded by PgiC1. Phylogenetic analysis of the nucleotide sequences implied that PgiC2 was silenced four times independently in the genus. Here we describe a psi PgiC2 from C. mildrediae, a species in which only PgiC1 is expressed. The discovery of the psi PgiC2 is significant because it confirms a formal prediction of the phylogenetic analysis. The psi PgiC2 includes 5,039 nucleotides corresponding to 18 of the 23 exons of PgiC, as well as the intervening introns and 3' nontranslated region. The absence of an increase of nucleotide substitutions in its "exons" suggests that the gene was silenced recently. The present study appears to be the first to establish that a specific duplicate gene locus regularly expressed in a group of related plant species has been silenced in one of them. The multiple independent silencings of PgiC2 suggest that it remained functional but inessential in ancestral lineages. We discuss the possibility that PgiC2 may have been preserved in these lineages by selection against mutants causing defective PGIC1- PGIC2 heterodimers.      

Homologies in Cambrian Onychophora

Marine animals related to Recent onychophorans form a significant component in Cambrian faunas. Twelve characters are analysed for homologies in the seven best known Cambrian onychophorans. New morphological evidence and homology analyses for several characters indicate an anteroposterior reversal of Hallucigenia and Microdictyon . Proposed expansion of the trunk in Microdietyon during compaction is rejected. A jaw is tentatively identified in Onychodictyon . The shape of the annulations and the disposition of the tenth leg pair in Aysheaia are reinterpreted, and the suggestion of two somites to the first appendage pair is rejected. A suggested morphocline may mirror the phylogeny of the group. The taxonomic confusion surrounding the supposed radiolarian family Eoconchariidae is cleared     

Different domains of Pseudomonas aeruginosa exoenzyme S activate distinct TLRs

Some bacterial products possess multiple immunomodulatory effects and thereby complex mechanisms of action. Exogenous administration of an important Pseudomonas aeruginosa virulence factor, exoenzyme S (ExoS) induces potent monocyte activation leading to the production of numerous proinflammatory cytokines and chemokines. However, ExoS is also injected directly into target cells, inducing cell death through its multiple effects on signaling pathways. This study addresses the mechanisms used by ExoS to induce monocyte activation. Exogenous administration resulted in specific internalization of ExoS via an actin-dependent mechanism. However, ExoS-mediated cellular activation was not inhibited if internalization was blocked, suggesting an alternate mechanism of activation. ExoS bound a saturable and specific receptor on the surface of monocytic cells. ExoS, LPS, and peptidoglycan were all able to induce tolerance and cross-tolerance to each other suggesting the involvement of a TLR in ExoS-recognition. ExoS activated monocytic cells via a myeloid differentiation Ag-88 pathway, using both TLR2 and the TLR4/MD-2/CD14 complex for cellular activation. Interestingly, the TLR2 activity was localized to the C-terminal domain of ExoS while the TLR4 activity was localized to the N-terminal domain. This study provides the first example of how different domains of the same molecule activate two TLRs, and also highlights the possible overlapping pathophysiological processes possessed by microbial toxins.     

CD34 mediates intestinal inflammation in Salmonella‐infected mice

CD34 is a highly glycosylated sialomucin expressed on a variety of cells, ranging from vascular endothelial cells to haematopoietic stem cells. Depending on its glycosylation state, CD34 has been shown to promote or inhibit cell adhesion and migration; however, a functional role for CD34 in the gut has not been determined. Using a model of Salmonella‐induced gastroenteritis, we investigated the role of CD34 in the context of infection. Upon oral infection, the number of CD34+ cells detected in the submucosa, vascular endothelium and lamina propria significantly increased in S. Typhimurium‐infected C57Bl/6 mice. The pathology of S. Typhimurium‐infected C57Bl/6 mice was characterized by recruitment of neutrophils to the site of inflammation, submucosal oedema and crypt destruction. In contrast, Cd34^?/? mice showed a delayed pathology, a defect in inflammatory cell migration into the intestinal tissue and enhanced survival. Importantly, this was not due to a lack of chemotactic signals in Cd34^?/? mice as these mice had either similar or significantly higher levels of pro‐inflammatory cytokines and chemokines post infection when compared with infected C57/Bl6 control mice. In summary, we demonstrate a novel role for CD34 in enhancing migration of inflammatory cells and thereby exacerbating host‐mediated immunopathology in the intestine of S. Typhimurium‐infected mice.     

Design of a bovine low-density SNP array optimized for imputation

The Illumina BovineLD BeadChip was designed to support imputation to higher density genotypes in dairy and beef breeds by including single-nucleotide polymorphisms (SNPs) that had a high minor allele frequency as well as uniform spacing across the genome except at the ends of the chromosome where densities were increased. The chip also includes SNPs on the Y chromosome and mitochondrial DNA loci that are useful for determining subspecies classification and certain paternal and maternal breed lineages. The total number of SNPs was 6,909. Accuracy of imputation to Illumina BovineSNP50 genotypes using the BovineLD chip was over 97% for most dairy and beef populations. The BovineLD imputations were about 3 percentage points more accurate than those from the Illumina GoldenGate Bovine3K BeadChip across multiple populations. The improvement was greatest when neither parent was genotyped. The minor allele frequencies were similar across taurine beef and dairy breeds as was the proportion of SNPs that were polymorphic. The new BovineLD chip should facilitate low-cost genomic selection in taurine beef and dairy cattle.