Moderate grazing promotes the root biomass in Kobresia meadow on the northern Qinghai–Tibet Plateau

Grazing is an important modulator of both plant productivity and biodiversity in grassland community, yet how to determine a suitable grazing intensity in alpine grassland is still controversy. Here, we explore the effects of different grazing intensities on plant biomass and species composition, both at community level and functional group level, and examines the productivity–species richness relationship under four grazing patterns: no grazing (CK), light grazing (LG), moderate grazing, (MG) and heavy grazing (HG), attempt to determine a suitable grazing intensity in alpine grassland. The results were as follows. The total aboveground biomass (AGB) reduced with increasing grazing intensity, and the response of plant functional groups was different. AGB of both sedges and legumes increased from MG to HG, while the AGB of forbs reduced sharply and the grass AGB remained steady. There was a significant positive relationship between productivity and species richness both at community level and functional group level. In contrast, the belowground biomass (BGB) showed a unimodal relationship from CK to HG, peaking in MG (8,297.72 ± 621.29 g/m²). Interestingly, the grassland community tends to allocate more root biomass to the upper soil layer under increasing grazing intensities. Our results suggesting that moderate levels of disturbance may be the optimal grassland management strategy for alpine meadow in terms of root production.     

Bovine colostrum promoted ileal health in newborn lambs at 24 h after birth: insight from intestinal morphology and innate immunity

The contribution of colostrum to passive immunity transfer and intestinal protection in newborn ruminants is well known; however, it is currently unclear how colostrum intake affects intestinal innate immunity. We investigated the effects of bovine colostrum intake on ileal morphology, expression of genes involved in intestinal innate immunity, and serum concentrations of inflammatory cytokines in newborn lambs. Twenty-seven newborn male Hu lambs were used, of which 18 were bottle-fed either bovine colostrum (C24h; n = 9) or bovine mature milk (M24h; n = 9) within the first 2 h after birth at an intake of approximately 8% of BW; the remaining nine lambs did not receive any feeding (N24h). Blood and ileal tissue samples were collected after the lambs were slaughtered at 24 h after birth. Ileal villus height and villus height-to-crypt depth ratio were significantly higher in C24h than those in N24h and M24h lambs (P < 0.01). Messenger RNA (mRNA) abundance of toll-like receptor (TLR)-2, TLR3, TLR4, TLR6, TLR7, TLR8 and tumour necrosis factor alpha in the ileum was lower in C24h than that in N24h lambs (P < 0.05). Moreover, C24h lambs had a lower TLR3 mRNA abundance (P < 0.01) and a trend of lower TLR6 (P = 0.06) and interleukin 1 beta (P = 0.08) expression compared with those in M24h lambs. We also observed strong positive correlations of tumour necrosis factor alpha expression with that of TLR2 (r = 0.71; P < 0.001), TLR4 (r = 0.88; P < 0.001) and TLR8 (r = 0.83; P < 0.001). Interestingly, the expression of barrier-related molecules, including mucin-13, lysozyme, claudin (CLDN)-1, CLDN2, CLDN4, CLDN7, CLDN12, occludin, zonula occluden-1 and junctional adhesion molecule-1, was consistently lower in C24h lambs than that in N24h and M24h lambs (P < 0.05). These results indicated that the beneficial roles of colostrum intake on intestinal protection in newborn lambs were associated with low TLR expression, which was reflected by improved intestinal development and reduced inflammatory response. Further studies using fluorescence in situ hybridisation and immunohistochemical methods are needed to further explore the mechanisms underlying the lower expression of intestinal barrier-related molecules due to colostrum feeding.     

Isolation and characterization of microsatellite DNA loci from Russell's snapper (Lutjanus russellii)

A total of 37 microsatellite loci from the Russell's snapper, Lutjanus russellii, were successfully isolated and characterized. Thirty‐four loci were polymorphic in L. russellii samples. Twenty of the 37 markers did not differ significantly from Hardy–Weinberg expected genotype proportions. Significant linkage disequilibrium was detected in one pairwise comparison. The numbers of alleles and observed heterozygosities in polymorphic loci ranged from two to 16 and from 0.41 to 0.95, respectively. These markers will be useful for studying the population genetic structure of this species.     

纤维乙醇研究现状及展望

介绍了近年来国内外纤维乙醇的研究现状,阐述了目前纤维乙醇生产存在的问题,分析了纤维乙醇产业化亟待解决的关键技术,展望了纤维乙醇的发展。     

EB病毒潜伏膜蛋白1调控鼻咽癌中转录因子c-Jun/Ets1间相互作用的实验研究

目的:探讨LMP1对鼻咽癌中转录因子c-Jun和Etsl表达的影响,以及对Etsl和AP-1间相互作用的调控,为LMP1的致瘤机制提供新的依据。方法:选用可调控表达LMP1的鼻咽癌细胞系pTet-on-LMP1 HNE2(L7细胞),通过针对c-Jun、Ets1的硫代反义寡核苷酸进行阻断,观察LMP1对c-Jun、Ets1表达的影响及其相互作用,蛋白质印迹法检测Ets-1、c-Jun蛋白质表达。免疫共沉淀(IP)结合Western blot研究c-Jun和Ets1相互结合的情况。结果:在不同浓度Dox诱导24 h后,Dox为0.6μg/mL时的c-Jun和Ets1表达均最强。随着Dox诱导时间的延长,L7细胞中c-Jun和Ets1的表达上调,至4 h达到最高。阻断c-Jun表达后,Ets1表达显著降低;阻断Ets1表达后,c-Jun表达显著降低。在Dox诱导的L7细胞总蛋白中,在IP沉淀的Ets1中存在c-Jun表达,并且在Dox 0.6μ/mL时最强;在IP沉淀的c-Jun中存在Ets1表达,同样在Dox 0.6μg/mL时最强。结论:EBV-LMP1可以调控转录因子c-Jun和Ets1表达,且在调控过程中可能存在c-Jun和Ets1间的相互作用。     

Shotgun glycopeptide capture approach coupled with mass spectrometry for comprehensive glycoproteomics

We present a robust and general shotgun glycoproteomics approach to comprehensively profile glycoproteins in complex biological mixtures. In this approach, glycopeptides derived from glycoproteins are enriched by selective capture onto a solid support using hydrazide chemistry followed by enzymatic release of the peptides and subsequent analysis by tandem mass spectrometry. The approach was validated using standard protein mixtures that resulted in a close to 100% capture efficiency. Our capture approach was then applied to microsomal fractions of the cisplatin-resistant ovarian cancer cell line IGROV-1/CP. With a Protein Prophet probability value greater than 0.9, we identified a total of 302 proteins with an average protein identification rate of 136 +/- 19 (n = 4) in a single linear quadrupole ion trap (LTQ) mass spectrometer nano-LC-MS experiment and a selectivity of 91 +/- 1.6% (n = 4) for the N-linked glycoconsensus sequence. Our method has several advantages. 1) Digestion of proteins initially into peptides improves the solubility of large membrane proteins and exposes all of the glycosylation sites to ensure equal accessibility to capture reagents. 2) Capturing glycosylated peptides can effectively reduce sample complexity and at the same time increase the confidence of MS-based protein identifications (more potential peptide identifications per protein). 3) The utility of sodium sulfite as a quencher in our capture approach to replace the solid phase extraction step in an earlier glycoprotein chemical capture approach for removing excess sodium periodate allows the overall capture procedure to be completed in a single vessel. This improvement minimizes sample loss, increases sensitivity, and makes our protocol amenable for high throughput implementation, a feature that is essential for biomarker identification and validation of a large number of clinical samples. 4) The approach is demonstrated here on the analysis of N-linked glycopeptides; however, it can be applied equally well to O-glycoprotein analysis.     

脑血管内皮细胞敲除Prmt5导致脑血管损伤及星形胶质细胞活化*

目的: 研究蛋白质精氨酸甲基转移酶5(protein arginine methyltransferase 5,Prmt5)在小鼠脑血管发育、稳态维持中的功能,并考察脑血管内皮细胞特异性敲除Prmt5后对中枢神经系统的影响。方法: 利用脑血管内皮细胞特异性表达SP-A-Cre转基因小鼠和Prmt5条件基因打靶小鼠交配,构建脑血管内皮细胞特异性Prmt5敲除小鼠。利用H-E染色、免疫荧光染色、激光散斑成像、Sulfo-NHS-Biotin染料灌注等方法评价脑血管内皮细胞特异性Prmt5敲除小鼠脑血管结构、脑血流量、血脑屏障渗透性等;利用实时定量PCR进一步检测补体C1q(complement C1q,C1q)、肿瘤坏死因子-α(tumor necrosis factor-α,TNF-α)和白细胞介素-1β(interleukin 1β,IL-1β)等细胞因子的表达水平。通过免疫荧光、Western blot等检测胶质纤维酸性蛋白(glial fibrillary acidic protein,GFAP)、S100钙结合蛋白β(S100 calcium-binding protein β protein,S100β)和补体C3(complement C3,C3)的表达,检测小鼠皮层、丘脑和小脑中星形胶质细胞活化水平。结果: 脑血管内皮细胞特异性敲除Prmt5导致血管损伤, C1q、TNF-α和IL-1β等炎症因子表达水平上调,活化星形胶质细胞比例明显增加。结论: 脑血管内皮细胞中Prmt5在小鼠脑血管稳态维持中发挥了重要功能。