组织工程静脉血管种子细胞的培养

目的获取可应用于静脉血管组织工程的种子细胞内皮细胞。方法选取北京地区雄性杂种犬,取其双侧颈外静脉,采用翻转后酶消法,获取原代内皮细胞,对其进行原代培养和传代培养,冻存、复苏和鉴定,并利用光学显微镜进行观察。结果获取犬的颈外静脉后,实验采取了翻转后酶消法,所获得的内皮细胞纯度和数量得到了提高;经过鉴定确实为内皮细胞来源;活性好,增殖快,在较短的时间内能够达到后期实验所需数量。结论经体外培养的犬的颈外静脉内皮细胞可以作为组织工程血管的种子细胞。     

T淋巴细胞在小鼠肾缺血再灌注损伤中的作用

目的研究T淋巴细胞在肾缺血再灌注损伤(IRI)导致的急性肾损害中的作用。方法BALB/c小鼠和BALB/c裸小鼠各24只,分别随机分为A1-4组和B1-4组,每组6只。双肾蒂阻断45 min后恢复血流建立肾IRI模型,假手术对照组I、RI后24、48和72 h时检测Scr、尿蛋白定量及肾病理学,A组检测脾T细胞亚群;对比BALB/c小鼠和BALB/c裸小鼠的肾功能下降、组织学损害程度以及脾T淋巴细胞亚群变化。结果A2-4组和B2-4组均有Scr和尿蛋白定量明显升高(P<0.05),且A组损害程度明显重于B组(P<0.05);A2-4组出现典型的IRI组织损害表现(P<0.05),B2-4组无明显IRI组织损害(P>0.05);A2-3组脾CD3 T细胞百分比较A1组升高(P<0.05),而CD4 /CD8 比值无明显变化(P>0.05)。结论T淋巴细胞是小鼠肾IRI导致急性肾损害的重要病理生理学因素。     

TNFα-initiated oxidative/nitrative stress mediates cardiomyocyte apoptosis in traumatic animals

Whole body non-penetrating trauma causes myocardial infarction in humans and mechanical trauma (MT) results in cardiac dysfunction in animals. Our recent study demonstrated that incubation of cardiomyocytes with plasma isolated from MT animals causes significant cardiomyocyte apoptosis that can be blocked by neutralization of TNFα. The present study attempted to obtain direct in vivo evidence to support that overproduction of TNFα plays a causative role in trauma-induced cardiomyocyte apoptosis. Non-lethal MT caused significant TNFα overproduction (2.4-fold at 1.5 h after MT) and increased cardiomyocyte apoptosis (starting 3 h and peaking 12 h after MT). Pharmacological inhibition of TNFα with etanercept or TNFα gene deletion reduced post-trauma myocyte apoptosis (P < 0.01). Expression of iNOS and NADPH oxidase, overproduction of NO and , and excessive protein nitration in the MT heart were all significantly reduced in etanercept-treated or TNFα^−/− mice, suggesting that oxidative/nitrative stress may contribute to TNFα-initiated myocyte apoptosis in MT hearts. Additional experiments demonstrated that inhibiting iNOS (1400W) or NADPH oxidase (apocynin), or scavenging peroxynitrite (FP15) significantly reduced myocyte apoptosis in MT animals (P < 0.01). Collectively, these data demonstrated that non-lethal mechanical trauma caused significant TNFα production that in turn stimulated myocardial apoptosis via oxidative/nitrative stress.     

Protein-protein interaction site prediction based on conditional random fields

MOTIVATION: We are motivated by the fast-growing number of protein structures in the Protein Data Bank with necessary information for prediction of protein-protein interaction sites to develop methods for identification of residues participating in protein-protein interactions. We would like to compare conditional random fields (CRFs)-based method with conventional classification-based methods that omit the relation between two labels of neighboring residues to show the advantages of CRFs-based method in predicting protein-protein interaction sites. RESULTS: The prediction of protein-protein interaction sites is solved as a sequential labeling problem by applying CRFs with features including protein sequence profile and residue accessible surface area. The CRFs-based method can achieve a comparable performance with state-of-the-art methods, when 1276 nonredundant hetero-complex protein chains are used as training and test set. Experimental result shows that CRFs-based method is a powerful and robust protein-protein interaction site prediction method and can be used to guide biologists to make specific experiments on proteins. AVAILABILITY: http://www.insun.hit.edu.cn/~mhli/site_CRFs/index.html. SUPPLEMENTARY INFORMATION: Supplementary data are available at Bioinformatics online.     

Expression of phytoene synthase gene (Psy) is enhanced during fruit ripening of Cara Cara navel orange (Citrus sinensis Osbeck)

Citrus is an important fruit crop as regards accumulation of carotenoids. In plant carotenoid biosynthesis, phytoene synthase gene (Psy) plays a key role in catalyzing the head-to-head condensation of geranylgeranyl diphosphate molecules to produce colorless phytoene. In the present paper, we reported the phytoene contents determination and characterization of Psy during fruit ripening of “Washington” navel orange and its red-fleshed mutant “Cara Cara”. Results showed that phytoene was exclusively accumulated in peel and pulp of “Cara Cara”. Although phytoene was observed accumulating with fruit ripening of “Cara Cara”, the contents in pulp were 10 times higher than those in peel. The isolated two Psy cDNAs were both 1520 bp in full length, containing 436 deduced amino acid residues, with a different amino acid at 412th. Genomic hybridization results showed that one or two copies might be present in “Cara Cara” and “Washington” genomes. During “Cara Cara” and “Washington” fruit coloration, expression of Psy was observed to be up-regulated, as revealed by tissue specific profiles in the flavedo, albedo, segment membrane and juice sacs. However, Psy expression in albedo of “Cara Cara” was higher than that in “Washington”, as evidenced by phytoene accumulation in the peel.     

Localization of QTLs for seed color using recombinant inbred lines of Brassica napus in different environments.

Yellow seed is one of the most important traits of Brassica napus L. Efficient selection of the yellow-seed trait is one of the most important objectives in oilseed rape breeding. Two recombinant inbred line (RIL) populations (RIL-1 and RIL-2) were analyzed for 2 years at 2 locations. Four hundred and twenty SSR, RAPD, and SRAP marker loci covering 1744 cM were mapped in 26 linkage groups of RIL-1, while 265 loci covering 1135 cM were mapped in 20 linkage groups of RIL-2. A total of 19 QTLs were detected in the 2 populations. A major QTL was detected adjacent to the same marker (EM11ME20/200) in both maps in both years. This major QTL could explain 53.71%, 39.34%, 42.42%, 30.18%, 24.86%, and 15.08% of phenotypic variation in 6 combinations (location x year x population). BLASTn analysis of the sequences of the markers flanking the major QTL revealed that the homologous region corresponding to this major QTL was anchored between genes At5g44440 and At5g49640 of Arabidopsis thaliana chromosome 5 (At C5). Based on comparative genomic analysis, the bifunctional gene TT10 is nearest to the homologue of EM11ME20/200 on At C5 and can be considered an important candidate gene for the major QTL identified here. Besides providing an effective strategy for marker-assisted selection of the yellow-seed trait in B. napus, our results also provide important clues for cloning of the candidate gene corresponding to this major QTL.     

Neuregulin-1 enhances depolarization-induced GABA release

Neuregulin-1 (NRG1), a regulator of neural development, has been shown to regulate neurotransmission at excitatory synapses. Although ErbB4, a key NRG1 receptor, is expressed in glutamic acid decarboxylase (GAD)-positive neurons, little is known about its role in GABAergic transmission. We show that ErbB4 is localized at GABAergic terminals of the prefrontal cortex. Our data indicate a role of NRG1, both endogenous and exogenous, in regulation of GABAergic transmission. This effect was blocked by inhibition or mutation of ErbB4, suggesting the involvement of ErbB4. Together, these results indicate that NRG1 regulates GABAergic transmission via presynaptic ErbB4 receptors, identifying a novel function of NRG1. Because both NRG1 and ErbB4 have emerged as susceptibility genes of schizophrenia, these observations may suggest a mechanism for abnormal GABAergic neurotransmission in this disorder.     

A new method of defense response analysis using a transient expression system in rice protoplasts

We established a new plant defense response assay using a transient expression system in rice protoplasts. The assay system sensitively detected defense induction by flagellin, which had previously been assigned to a specific elicitor. Our assay system provides a rapid and efficient way to dissect rice defense mechanisms.