提高糖基化的酶蛋白可结晶性研究 *

糖基化修饰是一类重要的翻译后修饰,对蛋白质的表达调控,折叠,分泌和功能等方面发挥着关键作用.酶是由活细胞产生的具有高度特异性和高效催化性的生物催化剂,酶的糖基化修饰对其生物催化特性和稳定性具有重要影响.研究糖基化修饰对酶蛋白的影响机制需要获取糖基化酶蛋白的结构,X-射线晶体衍射学是获得结构信息的重要技术手段,在糖基化酶蛋白的晶体衍射研究中,复杂,多样,不均一的糖基化修饰限制了该类酶的晶体生长,这是影响糖基化的酶蛋白结构解析的关键瓶颈问题.因此,如何提高糖基化的酶蛋白可结晶性是当前蛋白质结构研究的热点和难点.糖苷酶的去糖基处理,糖基转移酶抑制剂的引入和异源表达体系优化等手段都是当前研究领域提高糖基化的酶蛋白可结晶性的重要策略,这些手段可以在避免损害糖基化的酶蛋白稳定性和催化活性的同时提高其均一性.     

Application of Multiple-Locus Variable Number Tandem Repeat Analysis to Identify Outbreak-Associated Neisseria meningitides Serogroup C Sequence Type 4821 in China

Neisseria meningitidis (N. meningitidis) serogroup C sequence type (ST)-4821 caused an outbreak in 2010 in Shandong province of China. Twenty-one non-outbreak-associated strains were isolated, along with twenty-eight N. meningitides serogroup C ST-4821 isolates. Therefore, it’s essential to identify and clarify characterization of the real outbreak-associated strains with a rapid method during an outbreak investigation. In this study, multiple-locus variable number tandem repeat analysis (MLVA) was applied to analyze 84 N. meningitidis strains, among which 58 were recovered from two outbreaks and 26 were sporadic isolates. Three MLVA schemes with different combination of VNTR loci were tested, and two of them were suitable for isolates from China: scheme 2 with six loci was found to separate ST into finer resolution, and scheme 3 with five loci can be used to identify outbreak-associated isolates from the same outbreak that caused by N. meningitidis serogroup C ST-4821.     

Invariant NKT Cells Act as an Adjuvant to Enhance Th2 Inflammatory Response in an OVA-Induced Mouse Model of Asthma

Background

Invariant natural killer T cells (iNKT cells) are a unique subset of T lymphocytes and are considered to play an important role in the development of allergic bronchial asthma. Recently, iNKT cells were shown to play an immunoregulatory role in CD4⁺ and CD8⁺ T cell-mediated adaptive immune response. Allergen-specific Th2 inflammatory responses are an important part of the adaptive immune response in asthma. However, the regulatory functions of the Th2 inflammatory response in asthma have not been studied in detail.

Method

In this study, we have investigated the regulatory functions of iNKT cells on the Th2 inflammatory response in an ovalbumin (OVA)-induced murine model of asthma.

Results

Our results demonstrate that α-Galactosylceramide (α-GalCer) administration activated iNKT cells but could not induce the Th2 inflammatory response in wild-type (WT) mice. In the OVA-induced asthma model, α-GalCer administration and adoptive transfer of iNKT cells significantly augmented the Th2 inflammatory responses, including elevated inflammatory cell infiltration in the lung and bronchoalveolar lavage fluid (BALF); increased levels of IL-4, IL-5, and IL-13 in the BALF and splenocyte culture supernatant; and increased serum levels of OVA-specific IgE and IgG1. In addition, the Th2 inflammatory response was reduced, but not completely abrogated in CD1d^-/- mice immunized and challenged with OVA, compared with WT mice.

Conclusion

These results suggest that iNKT cells may serve as an adjuvant to enhance Th2 inflammatory response in an OVA-induced murine model of asthma.     

Transcriptomic Identification of ADH1B as a Novel Candidate Gene for Obesity and Insulin Resistance in Human Adipose Tissue in Mexican Americans from the Veterans Administration Genetic Epidemiology Study (VAGES)

Type 2 diabetes (T2D) is a complex metabolic disease that is more prevalent in ethnic groups such as Mexican Americans, and is strongly associated with the risk factors obesity and insulin resistance. The goal of this study was to perform whole genome gene expression profiling in adipose tissue to detect common patterns of gene regulation associated with obesity and insulin resistance. We used phenotypic and genotypic data from 308 Mexican American participants from the Veterans Administration Genetic Epidemiology Study (VAGES). Basal fasting RNA was extracted from adipose tissue biopsies from a subset of 75 unrelated individuals, and gene expression data generated on the Illumina BeadArray platform. The number of gene probes with significant expression above baseline was approximately 31,000. We performed multiple regression analysis of all probes with 15 metabolic traits. Adipose tissue had 3,012 genes significantly associated with the traits of interest (false discovery rate, FDR ≤ 0.05). The significance of gene expression changes was used to select 52 genes with significant (FDR ≤ 10^-4) gene expression changes across multiple traits. Gene sets/Pathways analysis identified one gene, alcohol dehydrogenase 1B (ADH1B) that was significantly enriched (P < 10^-60) as a prime candidate for involvement in multiple relevant metabolic pathways. Illumina BeadChip derived ADH1B expression data was consistent with quantitative real time PCR data. We observed significant inverse correlations with waist circumference (2.8 x 10^-9), BMI (5.4 x 10^-6), and fasting plasma insulin (P < 0.001). These findings are consistent with a central role for ADH1B in obesity and insulin resistance and provide evidence for a novel genetic regulatory mechanism for human metabolic diseases related to these traits.     

CRISPR-CAS9 D10A nickase target-specific fluorescent labeling of double strand DNA for whole genome mapping and structural variation analysis

We have developed a new, sequence-specific DNA labeling strategy that will dramatically improve DNA mapping in complex and structurally variant genomic regions, as well as facilitate high-throughput automated whole-genome mapping. The method uses the Cas9 D10A protein, which contains a nuclease disabling mutation in one of the two nuclease domains of Cas9, to create a guide RNA-directed DNA nick in the context of an in vitro-assembled CRISPR-CAS9-DNA complex. Fluorescent nucleotides are then incorporated adjacent to the nicking site with a DNA polymerase to label the guide RNA-determined target sequences. This labeling strategy is very powerful in targeting repetitive sequences as well as in barcoding genomic regions and structural variants not amenable to current labeling methods that rely on uneven distributions of restriction site motifs in the DNA. Importantly, it renders the labeled double-stranded DNA available in long intact stretches for high-throughput analysis in nanochannel arrays as well as for lower throughput targeted analysis of labeled DNA regions using alternative methods for stretching and imaging the labeled long DNA molecules. Thus, this method will dramatically improve both automated high-throughput genome-wide mapping as well as targeted analyses of complex regions containing repetitive and structurally variant DNA.     

陕西省汉中地区中国种子植物特有属的分析

汉中地区种子植物区系自然分布有中国特有属48属,隶属于33科,包括裸子植物1属,被子植物47属,其中单种属24属,少种属18属,多种属6属,从其生活习性上看,木本习性有25属,草本习性的有23属。本文主要分析了汉中地区分布的中国种子植物特有属的地理分布及特点,分析结果表明：其特点主要为显著的温带性质,众多的特有属和丰富的珍稀濒危物种,在地理分布上与华中,西南地区联系密切。     

Prevalence of Post-Stroke Cognitive Impairment in China: A Community-Based,Cross-Sectional Study

International hospital-based studies have indicated a high risk of cognitive impairment after stroke, evidence from community-based studies in China is scarce. To determine the prevalence of post-stroke cognitive impairment (PSCI) and its subtypes in stroke survivors residing in selected rural and urban Chinese communities, we conducted a community-based, cross-sectional study in 599 patients accounting for 48% of all stroke survivors registered in the 4 communities, who had suffered confirmed strokes and had undergone cognitive assessments via the Montreal Cognitive Assessment (MoCA), Mini-Mental State Examination (MMSE), and Hachinski Ischemia Scale (HIS). Detection of PSCI was based on scores in these neuropsychological scales. Factors potentially impacting on occurrence of PSCI were explored by comparing demographic characteristics, stroke features, and cardiovascular risk factors between patients with and without PSCI. The overall prevalence of PSCI was 80.97% (95%CI: 77.82%-84.11%), while that of non-dementia PSCI (PSCI-ND) and post-stroke vascular dementia (PSD) was 48.91% (95%CI: 44.91%-52.92%) and 32.05% (95%CI: 28.32%-35.79%), respectively. Prior stroke and complications during the acute phase were independent risk factors for PSCI. The risk of recurrent stroke survivors having PSCI was 2.7 times higher than for first-episode survivors, and it was 3 times higher for those with complications during the acute phase than for those without. The higher prevalence of PSCI in this study compared with previous Chinese studies was possibly due to the combined effects of including rural stroke survivors, a longer period from stroke onset, and different assessment methods. There is an urgent need to recognize and prevent PSCI in stroke patients, especially those with recurrent stroke and complications during the acute phase.