Three new species of the genus Lathrobium Gravenhorst (Coleoptera, Staphylinidae, Paederinae) from the Jiulongshan Natural Reserve, East China

Three new species of the genus Lathrobium Gravenhorst from Jiulongshan Natural Reserve, Zhejiang, East China, Lathrobium jiulongshanensesp. n., Lathrobium shenisp. n. and Lathrobium zhaotiexiongisp. n. are described and illustrated. A key to the Lathrobium species from Zhejiang Province is provided.     

Genome-Wide Analysis of bZIP-Encoding Genes in Maize

In plants, basic leucine zipper (bZIP) proteins regulate numerous biological processes such as seed maturation, flower and vascular development, stress signalling and pathogen defence. We have carried out a genome-wide identification and analysis of 125 bZIP genes that exist in the maize genome, encoding 170 distinct bZIP proteins. This family can be divided into 11 groups according to the phylogenetic relationship among the maize bZIP proteins and those in Arabidopsis and rice. Six kinds of intron patterns (a–f) within the basic and hinge regions are defined. The additional conserved motifs have been identified and present the group specificity. Detailed three-dimensional structure analysis has been done to display the sequence conservation and potential distribution of the bZIP domain. Further, we predict the DNA-binding pattern and the dimerization property on the basis of the characteristic features in the basic and hinge regions and the leucine zipper, respectively, which supports our classification greatly and helps to classify 26 distinct subfamilies. The chromosome distribution and the genetic analysis reveal that 58 ZmbZIP genes are located in the segmental duplicate regions in the maize genome, suggesting that the segment chromosomal duplications contribute greatly to the expansion of the maize bZIP family. Across the 60 different developmental stages of 11 organs, three apparent clusters formed represent three kinds of different expression patterns among the ZmbZIP gene family in maize development. A similar but slightly different expression pattern of bZIPs in two inbred lines displays that 22 detected ZmbZIP genes might be involved in drought stress. Thirteen pairs and 143 pairs of ZmbZIP genes show strongly negative and positive correlations in the four distinct fungal infections, respectively, based on the expression profile and Pearson''s correlation coefficient analysis.     

Study on a prolyl endopeptidase from the skeletal muscle of common carp (Cyprinus carpio)

A prolyl endopeptidase (PEP) was purified to homogeneity from the skeletal muscle of common carp using a procedure involving ammonium sulfate fractionation and column chromatography involving DEAE-Sephacel, Phenyl-Sepharose, DEAE-Sepharose Fast Flow, and hydroxyapatite. The molecular weight of the PEP was 82 kDa as determined by SDS-PAGE. Using Suc-Gly-Pro-MCA as a substrate, the optimal pH and temperature of the purified enzyme were pH 6.0 and 35 °C, respectively, and the K_m and k_cat were 8.33 μM and 1.71 S^?1, respectively. The activity of the PEP was inhibited by SUAM-14746, a specific inhibitor of prolyl endopeptidases, and was partially inhibited by the serine proteinase inhibitors PMSF and Pefabloc SC. According to peptide mass fingerprinting, 12 peptide fragments with a total of 134 amino acid residues were obtained, which were highly identical to prolyl endopeptidases from zebrafish (Danio rerio) and sponge (Amphimedon queenslandica), confirming the purified enzyme was a prolyl endopeptidase. Our present study for the first time reported the existence of a prolyl endopeptidase in fish muscle.     

Novel loci for field resistance to black-streaked dwarf and stripe viruses identified in a set of reciprocal introgression lines of rice (Oryza sativa L.)

Rice black-streaked dwarf virus (RBSDV) and stripe virus (RSV) are the two chronic viral diseases causing great damage to rice (Oryza sativa L.) production in China, and both are transmitted by the small brown planthopper (SBPH, Laodelphax striatellus Fallén). Quantitative trait loci (QTL) affecting field resistance to these two viral diseases were identified using QTL mapping software in a set of reciprocal introgression lines derived from the cross between Lemont and Teqing. A panel of 119 landraces was used for marker confirmation and allele mining. A total of 17 quantitative resistance loci (QRL) for the infection incidences of RBSDV and RSV were discovered and belong to 16 regions on all chromosomes except chromosome 12. Among them, 12 QRL were confirmed by association mapping, and many novel alleles at these loci were mined from the set of landraces. Only one region was found to be responsible for the genetic overlap between the field resistance against RBSDV and RSV, which was reported to be associated with SBPH resistance. The favorable alleles at the above novel and/or overlapping loci should be effective for marker-assisted selection breeding for resistance against the two diseases and the insect. Different strategies of varietal development and effective deployment against the two viral diseases are also discussed.     

Calcium sensing receptor regulates cardiomyocyte function through nuclear calcium

Nuclear Ca2+ plays a pivotal role in the regulation of gene expression. IP3 (inositol-1,4,5-trisphosphate) is an important regulator of nuclear Ca2+. We hypothesized that the CaR (calcium sensing receptor) stimulates nuclear Ca2+ release through IICR (IP3-induced calcium release) from perinuclear stores. Spontaneous Ca2+ oscillations and the spark frequency of nuclear Ca2+ were measured simultaneously in NRVMs (neonatal rat ventricular myocytes) using confocal imaging. CaR-induced nuclear Ca2+ release through IICR was abolished by inhibition of CaR and IP3Rs (IP3 receptors). However, no effect on the inhibition of RyRs (ryanodine receptors) was detected. The results suggest that CaR specifically modulates nuclear Ca2+ signalling through the IP3R pathway. Interestingly, nuclear Ca2+ was released from perinuclear stores by CaR activator-induced cardiomyocyte hypertrophy through the Ca2+-dependent phosphatase CaN (calcineurin)/NFAT (nuclear factor of activated T-cells) pathway. We have also demonstrated that the activation of the CaR increased the NRVM protein content, enlarged cell size and stimulated CaN expression and NFAT nuclear translocation in NRVMs. Thus, CaR enhances the nuclear Ca2+ transient in NRVMs by increasing fractional Ca2+ release from perinuclear stores, which is involved in cardiac hypertrophy through the CaN/NFAT pathway.     

Arrhythmogenic effect of sympathetic histamine in mouse hearts subjected to acute ischemia

The role of histamine as a newly recognized sympathetic neurotransmitter has been presented previously, and its postsynaptic effects greatly depended on the activities of sympathetic nerves. Cardiac sympathetic nerves become overactivated under acute myocardial ischemic conditions and release neurotransmitters in large amounts, inducing ventricular arrhythmia. Therefore, it is proposed that cardiac sympathetic histamine, in addition to norepinephrine, may have a significant arrhythmogenic effect. To test this hypothesis, we observed the release of cardiac sympathetic histamine and associated ventricular arrhythmogenesis that was induced by acute ischemia in isolated mouse hearts. Mast cell-deficient mice (MCDM) and histidine decarboxylase knockout (HDC(-/-)) mice were used to exclude the potential involvement of mast cells. Electrical field stimulation and acute ischemia-reperfusion evoked chemical sympathectomy-sensitive histamine release from the hearts of both MCDM and wild-type (WT) mice but not from HDC(-/-) mice. The release of histamine from the hearts of MCDM and WT mice was associated with the development of acute ischemia-induced ventricular tachycardia and ventricular fibrillation. The incidence and duration of induced ventricular arrhythmias were found to decrease in the presence of the selective histamine H(2) receptor antagonist famotidine. Additionally, the released histamine facilitated the arrhythmogenic effect of simultaneously released norepinephrine. We conclude that, under acute ischemic conditions, cardiac sympathetic histamine released by overactive sympathetic nerve terminals plays a certain arrhythmogenic role via H(2) receptors. These findings provided novel insight into the pathophysiological roles of sympathetic histamine, which may be a new therapeutic target for acute ischemia-induced arrhythmias.