Prevention of apoptosis by mitochondrial phosphatase PGAM5 in the mushroom body is crucial for heat shock resistance in Drosophila melanogaster

The heat shock (HS) response is essential for survival of all organisms. Although the machinery of the HS response has been extensively investigated at the cellular level, it is poorly understood at the level of the organism. Here, we show the crucial role of the mushroom body (MB) in the HS response in Drosophila. Null mutants of the mitochondrial phosphatase Drosophila PGAM5 (dPGAM5) exhibited increased vulnerability to HS, which was reversed by MB-specific expression of the caspase inhibitor p35, and similar vulnerability was induced in wild-type flies by knockdown of MB dPGAM5. Elimination of the MB did not affect the HS response of wild-type flies, but did increase the resistance of dPGAM5-deficient flies to HS. Thus, the MB may possess an apoptosis-dependent toxic function, the suppression of which by dPGAM5 appears to be crucial for HS resistance.     

Proteomic analysis of gingival crevicular fluid for discovery of novel periodontal disease markers

The protein composition of gingival crevicular fluid (GCF) may reflect the pathophysiology of periodontal diseases. A standard GCF proteomic pattern of healthy individuals would serve as a reference to identify biomarkers of periodontal diseases by proteome analyses. However, protein profiles of GCF obtained from apparently healthy individuals have not been well explored. As a step toward detection of proteomic biomarkers for periodontal diseases, we applied both gel-based and gel-free methods to analyze GCF obtained from healthy subjects as compared with supragingival saliva. To ensure optimized protein extraction from GCF, a novel protocol was developed. The proteins in GCF were extracted with high yield by urea buffer combined with ultrafiltration and the intensity of spots with supragingival saliva and GCF was compared using agarose two-dimensional electrophoresis. Eight protein spots were found to be significantly more intense in GCF. They included superoxide dismutase 1 (SOD1), apolipoprotein A-I (ApoA-I), and dermcidin (DCD). Moreover, GCF proteins from healthy subjects were broken down into small peptide fragments and then analyzed directly by LC-MS/MS analysis. A total of 327 proteins including ApoA-I, SOD1, and DCD were identified in GCF. These results may serve as reference for future proteomic studies searching for GCF biomarkers of periodontal diseases.     

Synthesis and PDF inhibitory activities of novel benzothiazolylidenehydroxamic acid derivatives

A novel series of benzothiazolylidenehydroxamic acid derivatives has been designed and synthesized as PDF inhibitors. Some of this novel class of PDF inhibitors exhibited micromolar order enzyme inhibitory activity and antibacterial activity.     

Capsicum frutescens L. in Southeast and East Asia, and its dispersal routes into Japan

Isozyme analyses were conducted to study the geographic variation ofCapsicum frutescens L. in Southeast and East Asia, and to investigate its dispersal routes into Japan. Eight enzymes (EST, EM, G6PD, GR, ME(A), PGI, PGM, ShDH) were variable among accessions ofC. frutescens in Southeast and East Asia. Accessions from the Ryukyu Islands were closely related to those in Indonesia, whereas accessions from the Bonin Islands showed exactly the same isozyme patterns as those from Indonesia and Northern Thailand. Accessions in the Ryukyu Islands were different from those in the Bonin Islands, suggesting that there may be two independent dispersal routes into Japan. One route was from Indonesia via the Philippines or Taiwan, or directly to the Ryukyu Islands, and another was from Indonesia via the Mariana Islands, or other islands in the Pacific, to the Bonin Islands.     

An algorithm for inferring complex haplotypes in a region of copy-number variation

Recent studies have extensively examined the large-scale genetic variants in the human genome known as copy-number variations (CNVs), and the universality of CNVs in normal individuals, along with their functional importance, has been increasingly recognized. However, the absence of a method to accurately infer alleles or haplotypes within a CNV region from high-throughput experimental data hampers the finer analyses of CNV properties and applications to disease-association studies. Here we developed an algorithm to infer complex haplotypes within a CNV region by using data obtained from high-throughput experimental platforms. We applied this algorithm to experimental data and estimated the population frequencies of haplotypes that can yield information on both sequences and numbers of DNA copies. These results suggested that the analysis of such complex haplotypes is essential for accurately detecting genetic differences within a CNV region between population groups.     

Thymidine phosphorylase inhibits the expression of proapoptotic protein BNIP3

An angiogenic factor, thymidine phosphorylase (TP), confers resistance to apoptosis induced by hypoxia. We investigated the molecular basis for the suppressive effect of TP on hypoxia-induced apoptosis using Jurkat cells transfected with TP cDNA, Jurkat/TP, and a mock transfectant, Jurkat/CV. TP and 2-deoxy-d-ribose, a degradation product of thymidine generated by TP enzymatic activity, suppressed hypoxia-induced apoptosis. They also inhibited the upregulation of hypoxia-inducible factor (HIF) 1α and the proapoptotic factor, BNIP3, and caspase 3 activation induced by hypoxia. Introduction of siRNA against BNIP3 in Jurkat cells decreased the proportion of apoptotic cells under hypoxic condition. These findings suggest that the suppression of BNIP3 expression by TP prevents, at least in part, hypoxia-induced apoptosis. Expression levels of TP are elevated in many malignant solid tumors and thus 2-deoxy-d-ribose generated by TP in these tumors might play an important role in tumor progression by preventing hypoxia-induced apoptosis.     

IL-1beta promotes neurite outgrowth by deactivating RhoA via p38 MAPK pathway

Expression of the pro-inflammatory cytokine interleukin-1 beta (IL-1β) is increased following the nervous system injury. Generally IL-1β induces inflammation, leading to neural degeneration, while several neuropoietic effects have also been reported. Although neurite outgrowth is an important step in nerve regeneration, whether IL-1β takes advantages on it is unclear. Now we examine how it affects neurite outgrowth. Following sciatic nerve injury, expression of IL-1β is increased in Schwann cells around the site of injury, peaking 1 day after injury. In dorsal root ganglion (DRG) neurons and cerebellar granule neurons (CGNs), neurite outgrowth is inhibited by the addition of myelin-associated glycoprotein (MAG), activating RhoA. IL-1β overcomes MAG-induced neurite outgrowth inhibition, by deactivating RhoA. Intracellular signaling experiments reveal that p38 MAPK, and not nuclear factor-kappa B (NF-κB), mediated this effect. These findings suggest that IL-1β may contribute to nerve regeneration by promoting neurite outgrowth following nerve injury.