Identification of miR-9 as a negative factor of insulin secretion from beta cells

MicroRNA is a novel class of small noncoding RNA that has been implicated in a variety of physiological and pathological processes, including glucose homeostasis and diabetes mellitus. So far, a few studies have reported that miRNAs may be an important regulator in glucose-stimulated insulin secretion (GSIS) pathway. However, the role of miRNAs in this process remains unclear. The levels of miRNAs in mouse islets and MIN6 cells were determined by quantitative RT-PCR. Concentration of insulin was determined by ELISA, and the expression of the target protein was determined with western blot assay. The overexpression and downregulation of miRNAs in MIN6 were conducted using cell transfection methods. And luciferase assay was used to measure the direct interaction between miRNAs and target messenger RNAs 3′UTR. miR-9 was screened out for it was downregulated under the effects of short-term high glucose, while long-term high glucose relatively increased miR-9 expression. The Stxbp1 expression was decreased with the overexpression of miR-9 in MIN6 cells and increased when miR-9 was downregulated. Moreover, it was verified by luciferase assay that miR-9 regulated Stxbp1 gene expression by directly targeting Stxbp1 messenger RNA 3′UTR. This study suggests that the pathway consisting of miR-9 and Stxbp1 plays a key role in β-cell function, thus contributing to the network of miRNA-insulin secretion and offering a new candidate for diabetes therapy.     

Effects of Rahnella aquatilis JZ-GX1 on Treat Chlorosis Induced by Iron Deficiency in Cinnamomum camphora

Journal of Plant Growth Regulation - With the increasing popularity of urban landscaping, there is a greater need to address iron deficiency and chlorosis in Cinnamomum camphora. Beneficial...     

Steroidal saponins from roots of Asparagus officinalis

Sarsasapogenin M (1) and sarsasapogenin N (2), two new oligospirostanosides with a unique aglycone moiety, (25S)-5beta-spirostan-3beta, 17alpha-diol, along with seven known compounds (25S)-5beta-spirostan-3beta-ol-3-O-beta-d-glucopyranosyl-(1,2)-[beta-d-xylopyranosyl-(1,4)]-beta-d-glucopyranoside (3), (25S)-5beta-spirostan-3beta-ol-3-O-beta-d-glucopyranosyl-(1,2)-beta-d-glucopyranoside (4), (25S)-5beta-spirostan-3beta-ol-3-O-alpha-l-rhamnopyranosyl-(1,2)-[alpha-l-rhamnopyranosyl-(1,4)]-beta-d-glucopyranoside (5), (25S)26-O-beta-d-glucopyranosyl-5beta-furost-20 (22)-ene-3beta,26-diol-3-O-beta-d-glucopyranosyl-(1,2)-beta-d-glucopyranoside (6), yamogenin (7), beta-sitosterol (8), and sitosterol-beta-d-glucoside (9) were isolated from the roots of Asparagus officinalis L. Their structures were determined by spectral analysis, including extensive 1D and 2D NMR experiments.     

Increase trend of correlation and phase synchrony of microwire iEEG before macroseizure onset

Micro/macrowire intracranial EEG (iEEG) signals recorded from implanted micro/macroelectrodes in epileptic patients have received great attention and are considered to include much information of neuron activities in seizure transition compared to scalp EEG from cortical electrodes. Microelectrode is contacted more close to neurons than macroelectrode and it is more sensitive to neuron activity changes than macroelectrode. Microwire iEEG recordings are inevitably advantageous over macrowire iEEG recordings to reveal neuronal mechanisms contributing to the generation of seizures. In this study, we investigate the seizure generation from microwire iEEG recordings and discuss synchronization of microwire iEEGs in four frequency bands: alpha (1−30 Hz), gamma (30−80 Hz), ripple (80–250 Hz), and fast ripple (>250 Hz) via two measures: correlation and phase synchrony. We find that an increase trend of correlation or phase synchrony exists before the macroseizure onset mostly in gamma and ripple bands where the duration of the preictal states varied in different seizures ranging up to a few seconds (minutes). This finding is contrast to the well-known result that a decrease of synchronization in macro domains exists before the macroseizure onset. The finding demonstrates that it is only when the seizure has recruited enough surrounding brain tissue does the signal become strong enough to be observed on the clinical macroelectrode and as a result support the hypothesis of progressive coalescence of microseizure domains. The potential ramifications of such an early detection of microscale seizure activity may open a new window on treatment by making possible disruption of seizure activity before it becomes fully established.     

The complete mitochondrial genomes of six heterodont bivalves (Tellinoidea and Solenoidea): variable gene arrangements and phylogenetic implications

Background

Taxonomy and phylogeny of subclass Heterodonta including Tellinoidea are long-debated issues and a complete agreement has not been reached yet. Mitochondrial (mt) genomes have been proved to be a powerful tool in resolving phylogenetic relationship. However, to date, only ten complete mitochondrial genomes of Heterodonta, which is by far the most diverse major group of Bivalvia, have been determined. In this paper, we newly sequenced the complete mt genomes of six species belonging to Heterodonta in order to resolve some problematical relationships among this subclass.

Principal Findings

The complete mt genomes of six species vary in size from 16,352 bp to 18,182. Hairpin-like secondary structures are found in the largest non-coding regions of six freshly sequenced mt genomes, five of which contain tandem repeats. It is noteworthy that two species belonging to the same genus show different gene arrangements with three translocations. The phylogenetic analysis of Heterodonta indicates that Sinonovacula constricta, distant from the Solecurtidae belonging to Tellinoidea, is as a sister group with Solen grandis of family Solenidae. Besides, all five species of Tellinoidea cluster together, while Sanguinolaria diphos has closer relationship with Solecurtus divaricatus, Moerella iridescens and Semele scaba rather than with Sanguinolaria olivacea.

Conclusions/Significance

By comparative study of gene order rearrangements and phylogenetic relationships of the five species belonging to Tellinoidea, our results support that comparisons of mt gene order rearrangements, to some extent, are a useful tool for phylogenetic studies. Based on phylogenetic analyses of multiple protein-coding genes, we prefer classifying the genus Sinonovacula within the superfamily Solenoidea and not the superfamily Tellinoidea. Besides, both gene order and sequence data agree that Sanguinolaria (Psammobiidae) is not monophyletic. Nevertheless, more studies based on more mt genomes via combination of gene order and phylogenetic analysis are needed to further understand the phylogenetic relationships in subclass Heterodonta.     

Inactivation of Giardia lamblia and Giardia canis cysts by combined and free chlorine

Free chlorine and a combined organic N-chloramine (3-chloro-4,4-dimethyl-2-oxazolidinone, compound 1) were compared for efficacy as disinfectants against an admixture of cysts of Giardia lamblia and Giardia canis in water solution under a variety of test conditions; variables were pH, temperature, and water quality. In general, compound 1 was found to reduce the giardial excystation in the solutions at lower concentration or shorter contact time at a given total chlorine concentration than did free chlorine.