条锈菌诱导的抗锈小麦种质的基因表达分析

以条锈菌接种前后的抗条锈病种质N 95175的小麦幼苗叶片为材料,利用抑制消减杂交技术,构建了条锈菌接种初期小麦抗性种质叶片的SSH-cDNA文库。通过对文库中随机选取的50个阳性克隆提取质粒,进行测序,共获得已知功能的EST序列14条,如蛋白激酶、锌指蛋白、细胞色素P 450和OM T 1等抗病相关基因,它们涉及植物的信号传导、转录调控、丙烷代谢途径及防卫反应等方面。     

A bioinformatics-based update on microRNAs and their targets in rainbow trout (Oncorhynchus mykiss)

MicroRNAs (miRNAs) participate in various vitally biological processes via controlling target genes activity and thousands of miRNAs have been identified in many species to date, including 18,698 known animal miRNA in miRBase. However, there are only limited studies reported in rainbow trout (Oncorhynchus mykiss) especially via the computational-based approaches. In present study, we systematically investigated the miRNAs in rainbow trout using a well-developed comparative genome-based homologue search. A total of 196 potential miRNAs, belonging to 124 miRNA families, were identified, most of which were firstly reported in rainbow trout. The length of miRNAs ranged from 17 to 24 nt with an average of 20 nt while the length of their precursors varied from 47 to 152 nt with an average of 85 nt. The identified miRNAs were not evenly distributed in each miRNA family, with only one member per family for a majority, and multiple members were also identified for several families. Nucleotide U was dominant in the pre-miRNAs with a percentage of 30.04%. The rainbow trout pre-miRNAs had relatively high negative minimal folding free energy (MFE) and adjusted MFE (AMFE). Not only the mature miRNAs but their precursor sequences are conserved among the living organisms. About 2466 O. mykiss genes were predicted as potential targets for 189 miRNAs. Gene Ontology (GO) analysis showed that nearly 2093, 2107, and 2081 target genes are involved in cellular component, molecular function, and biological processes respectively. KEGG pathway enrichment analysis illuminated that these miRNAs targets might regulate 105 metabolic pathways, including those of purine metabolism, nitrogen metabolism, and oxidative phosphorylation. This study has provided an update on rainbow trout miRNAs and their targets, which represents a foundation for future studies.     

32份辣椒种质遗传多样性的同工酶分析

基于叶片的过氧化物酶(POD)、超氧化物歧化酶(SOD)及花蕾的酯酶(EST)同工酶酶谱的聚丙烯酰胺凝胶电泳(PAGE)分析,对32份辣椒种质的遗传多样性进行了研究。结果表明:(1)共产生29种谱带,其中POD谱带13种234条,多态性位点比例(PPL)和相对迁移率(Rf)变化范围分别为50.0%~80.0%和0.05~0.69;SOD谱带8种140条,PPL、Rf分别为100.0%、0.38~0.88;EST谱带8种163条,PPL、Rf分别为50.0%~87.5%、0.16~0.89。(2)共发现多态位点26个,PPL、总基因频率(Pt)、等位基因平均数(A)、Nei基因多样性指数(He)、Shannon信息指数(SII)、平均遗传一致度(GI)和遗传距离(GD)分别为89.66%、0.578 7、1.896 6、0.272 2、0.415 2、0.736 6和0.314 3;32份辣椒材料的Jaccard遗传相似系数为0.348~0.905,并聚类为4个栽培种群。(3)4个栽培种群内基因多样度(HS)为0.143 6;种群间基因多样度(DST)、基因分化系数(GST)、GI和GD分别为0.149 4、0.51、0.784 4和0.246 6。(4)9份紫色辣椒种质共发现多态位点16个,PPL、Pt、A、He、SII、GI和GD分别为55.17%、0.611 1、1.551 7、0.194 1、0.291 9、0.781 6和0.249 4。研究认为,32份辣椒材料的总体、栽培种间和种内以及紫色材料间遗传分化程度大,为紫色辣椒杂交育种的亲本选配与绿色品种的遗传改良提供了参考依据。     

Analysis of genetic variability of South American wild rice populations (Oryza glumaepatula) with isozymes and RAPD markers

The knowledge of population structure and genetic diversity of wild relatives of rice is needed to investigate their evolutionary history and potential use in breeding programs. Very little is known about the wild rice species ( Oryza spp.), particularly those that are native to South America. A study using isozyme and RAPD markers was conducted to estimate the level of genetic diversity of four South American wild rice populations ( Oryza glumaepatula ) recently collected in the Amazon forest and western Brazil rivers. F -statistics and genetic diversity parameters calculated from isozyme and RAPD markers indicated high values for inbreeding coefficients and differentiation among the four populations. In agreement with this, a pattern of greater variation between than within populations was observed with both types of markers. These findings were corroborated by an AMOVA analysis, which indicated that a large portion of the total genetic variation was attributed to regional divergence. The partition of the AMOVA analysis among populations showed that most of the genetic diversity was due to differences among populations. This distribution pattern of genetic variation of O. glumaepatula populations is in agreement with the expectation for an autogamous species and provides important baseline data for conservation and collection strategies for this species.     

Herbivory-induced glucose transporter gene expression in the brown planthopper,Nilaparvata lugens

Nilaparvata lugens, the brown planthopper (BPH) feeds on rice phloem sap, containing high amounts of sucrose as a carbon source. Nutrients such as sugars in the digestive tract are incorporated into the body cavity via transporters with substrate selectivity. Eighteen sugar transporter genes of BPH (Nlst) were reported and three transporters have been functionally characterized. However, individual characteristics of NlST members associated with sugar transport remain poorly understood. Comparative gene expression analyses using oligo-microarray and quantitative RT-PCR revealed that the sugar transporter gene Nlst16 was markedly up-regulated during BPH feeding. Expression of Nlst16 was induced 2 h after BPH feeding on rice plants. Nlst16, mainly expressed in the midgut, appears to be involved in carbohydrate incorporation from the gut cavity into the hemolymph. Nlst1 (NlHT1), the most highly expressed sugar transporter gene in the midgut was not up-regulated during BPH feeding. The biochemical function of NlST16 was shown as facilitative glucose transport along gradients. Glucose uptake activity by NlST16 was higher than that of NlST1 in the Xenopus oocyte expression system. At least two NlST members are responsible for glucose uptake in the BPH midgut, suggesting that the midgut of BPH is equipped with various types of transporters having diversified manner for sugar uptake.     

Isozyme differentiation of aldolase and pyruvate kinase in fetal,regenerating, preneoplastic,and malignant rat hepatocytes during culture

Summary Aldolase and pyruvate kinase isozymes were investigated in cultured hepatocytes from fetal, regenerating, and 2-acetyl-aminofluorene-fed rat liver as well as in some epithelial liver cell lines. Our results show that: (a) cell proliferation and prolonged expression of specific isozymes were found only in cultured hepatocytes from 17-day old fetuses; (b) the fetal type of pyruvate kinase expressed in regenerating and carcinogen-treated liver was temporarily lost only in cultured hepatocytes from regenerating liver; (c) the adult type of aldolase and pyruvate kinase was absent in one epithelial cell line derived from a carcinogen-treated liver and in the hepatoma tissue cell (HTC) line but was found in the Faza clone of the Reuber H₃₅ cell line during the 50 first passages in vitro; and (d) the isozyme pattern of pyruvate kinase was always more strongly shifted than that of aldolase. The observations suggest that: (a) hepatocytes from carcinogen-treated liver exhibit the same lack of ability to proliferate in primary culture as normal adult hepatocytes; (b) adult hepatocytes can produce fetal isozymes without prior cell division; (c) pyruvate kinase is a stronger marker of dedifferentiation (retrodifferentiation) than aldolase; and (d) regulatory processes of isozyme expression are different during ontogenesis, regeneration, and hepatocarcinogenesis. This work was supported by the “Institut National de la Santé et de la Recherche Médicale” and the “Fondation pour la Recherche Medicale Fran?aise”     

Purification and Properties of α-Glucosidase and Glucoamylase from Lentinus edodes (Berk.) Sing.

An α-glucosidase and a glucoamylase have been isolated from fruit bodies of Lentinus edodes (Berk.) Sing., by a procedure including fractionation with ammonium sulfate, DEAE-cellulose column chromatography, and preparative gel electrofocusing. Both of them were homogeneous on gel electrofocusing and ultracentrifugation. The molecular weight of α-glucosidase and glucoamylase was 51,000 and 55,000, respectively. The α-glucosidase hydrolyzed maltose, maltotriose, phenyl α-maltoside, amylose, and soluble starch, but did not act on sucrose. The glucoamylase hydrolyzed maltose, maltotriose, phenyl α-maltoside, soluble starch, amylose, amylopectin, and glycogen, glucose being the sole product formed in the digests of these substrates. Both enzymes hydrolyzed phenyl a-maltoside into glucose and phenyl α-glucoside. The glucoamylase hydrolyzed soluble starch, amylose, amylopectin, and glycogen, converting them almost completely into glucose. It was found that β-glucose was liberated from amylose by the action of glucoamylase, while α-glucose was produced by the α-glucosidase.

Maltotriose was the main α-glucosyltransfer product formed from maltose by the α-glucosidase.     

5,7-Dodecadien-1-ol: Candidate for the Sex Pheromone of the Pine Moth

Ferredoxin-nitrite reductase (EC 1.7.7.1), an enzyme which catalyzes the 6-electron reduction of nitrite to ammonia, has been isolated from Spinacia oleracea. The isolated enzyme was homogeneous by disc electrophoresis with polyacrylamide gel. The molecular weight of the enzyme was estimated to be 86,000 by Ultrogel AcA 34 gel filtration. In the oxidized form, the enzyme had absorption maxima at 278, 388 (Soret band), 573 (α band) and 690 nm, indicating that siroheme is directly involved in the catalysis of nitrite reduction. This absorption spectrum was modified by sulfite, hydroxylamine and cyanide. The enzyme exhibited electron paramagnetic resonance signals with g values of 6.9 and 5.2, which are characteristic of a high spin Fe³⁺ -siroheme in the molecule. These signals disappeared upon the addition of dithionite or nitrite. This isolated enzyme also contained four moles of labile sulfide and 7 g-atoms of iron per 86,000 g of protein.