Comparative mapping of QTLs for agronomic traits of rice across environments by using a doubled-haploid population

We report here the RFLP mapping of quantitative trait loci (QTLs) which affect some important agronomic traits in cultivated rice. An anther culture-derived doubled-haploid (DH) population was established from a cross between indica and japonica rice varieties. A molecular linkage map comprising 137 markers was constructed based on this population which covered the rice genome at intervals of 14.8 cM on average. The linkage map was used to locate QTLs for such important agronomic traits as heading date, plant height, number of spikelets per panicle, number of grains per panicle, 1 000-grain weight and the percentage of seed set, by interval mapping. Evidence of genotype-by-environment interaction was found by comparing QTL maps of the same population grown in three diverse environments. A total of 22 QTLs for six agronomic traits was detected which were significant in at least one environment, but only seven were significant in all three environments; seven were significant in two environments and eight could only be detected in a single environment. However, QTLs-by-environment interaction was trait dependent. QTLs for spikelets and grains per panicle were common across environments while traits like heading date and plant height were more sensitive to environment. Received: 22 February 1996 / Accepted: 10 May 1996     

A variant ECE1 allele contributes to reduced pathogenicity of Candida albicans during vulvovaginal candidiasis

Vulvovaginal candidiasis (VVC), caused primarily by the human fungal pathogen Candida albicans, results in significant quality-of-life issues for women worldwide. Candidalysin, a toxin derived from a polypeptide (Ece1p) encoded by the ECE1 gene, plays a crucial role in driving immunopathology at the vaginal mucosa. This study aimed to determine if expression and/or processing of Ece1p differs across C. albicans isolates and whether this partly underlies differential pathogenicity observed clinically. Using a targeted sequencing approach, we determined that isolate 529L harbors a similarly expressed, yet distinct Ece1p isoform variant that encodes for a predicted functional candidalysin; this isoform was conserved amongst a collection of clinical isolates. Expression of the ECE1 open reading frame (ORF) from 529L in an SC5314-derived ece1Δ/Δ strain resulted in significantly reduced vaginopathogenicity as compared to an isogenic control expressing a wild-type (WT) ECE1 allele. However, in vitro challenge of vaginal epithelial cells with synthetic candidalysin demonstrated similar toxigenic activity amongst SC5314 and 529L isoforms. Creation of an isogenic panel of chimeric strains harboring swapped Ece1p peptides or HiBiT tags revealed reduced secretion with the ORF from 529L that was associated with reduced virulence. A genetic survey of 78 clinical isolates demonstrated a conserved pattern between Ece1p P2 and P3 sequences, suggesting that substrate specificity around Kex2p-mediated KR cleavage sites involved in protein processing may contribute to differential pathogenicity amongst clinical isolates. Therefore, we present a new mechanism for attenuation of C. albicans virulence at the ECE1 locus.     

Cloning and expression of mannosylphospho dolichol synthase from bovine adrenal medullary capillary endothelial cells

Mannosylphospho dolichol synthase (DPMS) is a critical enzyme in the biosynthesis of lipid-linked oligosaccharide (LLO; Glc₃Man₉GlcNAc₂-PP-Dol), a pre-requisite for asparagine-linked (N-linked) protein glycosylation. We have shown earlier that DPMS is important for angiogenesis, i.e., endothelial cell proliferation. This is true when cAMP is used for intracellular signaling. During cAMP signaling, DPMS is activated and ER stress is reduced. To understand the activation of DPMS at the molecular level we have isolated a cDNA clone for the DPMS gene (bDPMS) from the capillary endothelial cells of bovine adrenal medulla. DNA sequencing and the deduced amino acid sequence have established that bDPMS has a motif to be phosphorylated by cAMP-dependent protein kinase (PKA). Based on the sequence information Serine 165 has been found to be the phosphorylation target in bDPMS. Hydropathy Index when plotted against amino acid number indicates the presence of a hydrophobic region around the amino acid residues 120–160, supporting that bDPMS has one membrane spanning region. The recombinant bDPMS has now been purified as His-tag protein with an apparent molecular weight of M _r 33 kDa. Additionally, we show here that overexpression of DPMS is indeed angiogenic. The capillary endothelial cells proliferate at a higher rate carrying the DPMS overexpression plasmid over the parental cells or the vector.     

基于数码相片Gamma校正的水稻叶面积指数估算

随着数码相机的日益普及,利用数码相机进行作物叶面积指数(LAI)测量不断得以应用。由于数码相机成像时会对入射光辐射强度进行Gamma编码变换,输出的相片DN(Digital Number)值与入射光辐射强度呈非线性关系,会造成在确定相片中植被叶片与背景的分割阈值时出现误差,并最终导致LAI估算存在较大不确定性。以水稻为研究对象,获取不同生长期水稻冠层相片并结合同步LAI 2000测量的LAI数据,基于相片Gamma校正原理,对水稻不同生长期冠层相片进行Gamma校正,在此基础上利用冠层孔隙率方法,估算不同生长期水稻LAI。结果表明,经过Gamma校正相片估算的水稻LAI总体精度有显著提高,相片估算的IMAGE LAI与LAI-2000测量值比较的决定系数达到0.71(P0.05)。在整个观测期内,两种方法观测的LAI值在时间变化趋势上表现一致,但在不同生长期内存在差别,在水稻分蘖期和拔节期相片估算的IMAGE LAI要高于LAI-2000测量值,孕穗期到抽穗期期间IMAGE LAI低于LAI-2000测量值,乳熟期到成熟期IMAGE LAI又高于LAI-2000的观测结果。     

渤海东部海域秋季底层游泳动物种类组成及群落多样性

根据2014年9月在渤海东部海域(37°40'—38°20'N、120°00'—121°20'E)进行的游泳动物底拖网调查数据,应用相对重要性指数、生物多样性指数、群落结构多元统计分析等方法对该海域游泳动物种类组成及群落多样性特征进行了分析。结果表明:调查海域共捕获游泳动物54种,以头足类枪乌贼(Loliolus spp.)为绝对优势种;游泳动物资源密度为28.82kg/h和5166尾/h。游泳动物种类Margalef丰富度指数(D)的变化范围为1.99—3.67,Shannon-Wiener多样性指数(H')变化范围为0.89—2.28,Pielou均匀度指数(J')变化范围为0.29—0.69。群落结构多元统计分析表明,渤海东部海域游泳动物群落结构以60%的相似性可划分为3个组群:长岛群岛海域组群(A组群)、龙口海域组群(B组群)和蓬莱海域组群(C组群);ANOSIM分析表明,组群之间差异极显著,两两之间差异亦极显著。受增殖放流影响,C组群资源密度和种类多样性均保持较高的水平,而A、B组群人为活动频繁,过度捕捞严重,对海域生态环境和渔业资源整体结构的破坏较大。     

莱州湾中国对虾生长特性及其空间分布

根据2010年5月—10月调查资料,对山东莱州湾中国对虾(Fenneropenaeus chinensis)的资源状况、生长特性及其空间分布进行了研究。莱州湾放流前本底调查资料表明,目前山东莱州湾中国对虾捕捞产量主要来源于增殖放流,且在一定条件下捕捞产量与放流数量成正相关关系。依据2010年中国对虾生物学数据,应用R语言命令对中国对虾体长体重关系和体长生长方程进行了拟合,并对拟合系数进行了显著性检验,结果表明中国对虾体长与体重系数a、b处于显著水平(P0.05),中国对虾体长生长方程拟合系数K、t_0、L_∞处于极显著水平(P0.001),故拟合效果明显,获得为中国对虾生长参数雌虾为K=0.0226、t_0=37.45d、L_∞=200.77 mm、W_∞=80.50 g、t_r=85.18d(8月4日),雄虾为:K=0.0419、t_0=40.25d、L_∞=145.81 mm、W_∞=23.37 g、tr=67.24d(7月18日),与20世纪80年代相比,中国对虾个体明显减小,生长速度加快,生长拐点提前了1个月。另外,根据大面调查体长数据,对各个站位体长组出现频率进行Ward聚类分析,利用R语言聚类树的融合水平值定义划分水平,选择具有最大跳跃的分组水平,将中国对虾虾群大致可分为两个组群,河口组和深水组,同时按照各体长组的多度值大小,探讨了各组内具有代表性的分类体长组,结果表明,河口组的中国对虾以体长125—135 mm为主,深水组以体长115—125 mm和105—115mm为主,河口组个体明显大于深水组;河口组分布区入海河流较多,饵料生物丰富,以软泥底质为主,有利于中国对虾的摄食和前期保护,深水组分布于莱州湾中东部,蟹类资源相对较高,且以沙质底质为主,对中国对虾的生长与保护产生一定的影响。     

Overexpression of fucosyltransferase IV in A431 cell line increases cell proliferation

Fucosyltransferase IV is an essential enzyme that catalyzes the synthesis of fucosylated oligosaccharides by transferring GDP-fucose to the terminal N-acetylglucosamine with the alpha1,3-linkage. Lewis Y oligosaccharide has a terminal alpha1,3-linked fucose residue and elevation of Lewis Y level is seen in many epithelial cancers. The mechanism of Lewis Y elevation in neoplastic cells is still largely unknown. To study the impact of fucosyltransferase IV on Lewis Y expression and its role on neoplastic cell proliferation, a pEGFP-N1-FUT4 recombinant plasmid was developed and stably transfected into A431 cells. We found that fucosyltransferase IV overexpression promoted cell proliferation and increased the expression of proliferating cell nuclear antigen that correlated with Lewis Y augmentation. Cell cycle analysis demonstrated that fucosyltransferase IV overexpression facilitated cell cycle progression. In conclusion, fucosyltransferase IV overexpression augments Lewis Y expression to trigger neoplastic cell proliferation. These studies suggest that fucosyltransferase IV may serve as a potential therapeutic target for the treatment of Lewis Y-positive epithelial cancers.     

鲤春病毒糖蛋白(G)基因的分离及同源性比较

通过RT-PCR和巢氏PCR方法从疑似鲤春病毒(SVCV)侵染的镜鲤肝组织中获得了鲤春病毒糖蛋白(G)基因。通过序列测定与分析,所获得的鲤春病毒糖蛋白(G)基因由606个核苷酸组成,编码一个由202个氨基酸组成的糖蛋白。通过NCBIblast与9个来自不同国家或地区的鲤春病毒糖蛋白(G)基因序列比对分析,发现获得的鲤鱼春季病毒糖蛋白G基因DNA序列与美国分离的AY527273株同源性最高为99.8%,与中国分离的AY842485株同源性次高为98.7%,与英国分离的两个序列SVI538065和SVI538066株的同源性为98.2%,而与其它国家的分离株如SVU18101、SVI318079、SVI538061、SVI538062、SVI538063的同源性最差,仅为89.4%~90.0%。氨基酸同源性分析结果与DNA同源性分析结果一致,所获得的鲤春病毒糖蛋白G基因氨基酸推导序列与其它9个分离株的氨基酸同源性在89.6%~99.5%之间。对SVCV不同分离株遗传变异和进化关系的分析为下一步开展SVCV快速诊断方法的研究和疫苗的研制奠定了基础。     

黄河调水调沙对黄河口海域双酚A的影响

于2011年6—7月黄河调水调沙前、中期、后对黄河口海域双酚A(BPA)污染情况进行调查,研究了调水调沙对黄河口海域双酚A的影响。结果表明:黄河口13个站位表层海水和沉积物中均有双酚A检出,以调水调沙前测得的海水和沉积物中双酚A含量评估黄河口附近双酚A的污染程度。海水中双酚A浓度范围为13.6—64.0 ng/L,平均浓度为26.2 ng/L;沉积物中双酚A的浓度为0.559—2.73μg/kg干重,平均浓度为1.19μg/kg,是海水中平均含量的48倍。黄河河口区域海水中双酚A浓度受调水调沙影响而呈现较大变化,调水调沙后双酚A浓度明显增加,调水调沙前、后呈显著性差异(P0.01),说明陆源输入是黄河口区域中双酚A的主要污染来源。离入海口近的站位沉积物中双酚A浓度受调水调沙影响较大,呈显著性差异(P0.01),调水调沙后含量显著降低。黄河口海域已经遭受双酚A污染,存在生态安全问题。