鹅源大肠埃希菌的分离与鉴定

从临盏床疑似大肠埃希菌感染的病雏鹅的组织分离到31株细菌,通过培养特性和生化试验确定其中27株为大肠埃希菌。血清学试验表明,其中7株（25．93％）为026型,6株（22．22％）为078型,4株（14．81％）为01型,3株（11．11％）为018型,2株（7．41％）为0117型,5株（18．52％）未能定型。应用PCR方法检测了27株大肠埃希菌的F1菌毛与毒力岛HPI基因,结果表明24株（88．89％）为F1^＋大肠埃希菌,7株（25．939／5）为HPI^＋大肠埃希菌（其中4株为F1^＋）。药敏试验表明,所有菌株均对头孢唑林、呋喃妥因敏感,部分菌株对庆大霉素、环丙沙星敏感,而对多黏菌素、四环素、林可霉素均为耐药。     

不同栽培方式下春玉米养分累积与转运特征

通过两年定位试验,研究不同栽培方式下春玉米产量、干物质累积、养分累积与转运特征,为春玉米的养分高效利用提供理论依据。2012～2013年在吉林省农安县靠山镇进行田间试验,设置3种栽培模式,分别为农户模式（TRA）、优化栽培模式1(OPT-1)、优化栽培模式2(OPT-2),供试品种均为利民33,在玉米6展叶（V6）、12展叶（V12）、开花（R1）、灌浆（R3）、成熟（R6）5个生育时期测定群体氮、磷、钾养分吸收动态,并测定产量构成。结果表明：在3种栽培模式中,两年产量的平均值表现为OPT-2>OPT-1>TRA,与TRA处理相比,OPT-2处理下的产量两年间分别增加了24.6%和24.2%;OPT-1和OPT-2处理下两年的收获穗数平均值分别增加65.4%和81.5%。OPT-2处理下的干物质累积在整个生育进程中均显著高于OPT-1和TRA处理,至成熟期,OPT-2处理下干物质累积量较OPT-1处理高10.0%,较TRA处理高24.2%;从6展叶期至成熟期,各处理下植株氮素、磷素与钾素累积量逐渐增加,累积速率均在开花期达到最大,至成熟期,OPT-2处理下整株的氮、磷、钾积...     

环境因素对淡水浮丝藻生长及产生嗅味的影响

研究温度、营养盐浓度以及光照强度对淡水浮丝藻(Planktothrix sp.)及其代谢产物二-甲基异莰醇(2-MIB)的影响,为控制丝状蓝藻生长及预警水体嗅味物质污染提供实践依据。浮丝藻由中国科学院水生生物研究所淡水藻种库分离于安徽巢湖;设置的实验温度为15、20、25、30℃,BG-11营养盐溶液体积分数为20%、30%、50%、100%,光照为1 000、2 000、3 000、4 000 lx。结果表明,温度对浮丝藻生长密度、总2-MIB生成量及胞外2-MIB分泌量影响最显著,25℃是浮丝藻最适宜生长温度,最高细胞密度可达6.04×10⁵个/mL,30℃是其最适宜的产2-MIB温度,总2-MIB生成量和胞外2-MIB分泌量均最高,分别为3.64×10³ng/L和2.78×10³ng/L;其次为营养盐浓度,增大BG-11营养盐浓度,浮丝藻生长密度和总2-MIB生成量会随之增加,低浓度营养盐时胞外2-MIB分泌量所占比例较高,表明低浓度营养盐更有利于浮丝藻进行胞外2-MIB分泌;光照对浮丝藻生长及产嗅味物质影响较小,...     

鹰爪虾形态性状和体重的通径分析及灰色关联分析

为探究鹰爪虾(Trachypenaeus curvirostirs)形态性状和体重的关系,本研究测定了体重(Y)及全长(X₁)、体长(X₂)、头胸甲长(X₃)、头胸甲宽(X₄)、头胸甲高(X₅)、第1腹节长(X₆)、第1腹节宽(X₇)、第1腹节高(X₈)、第6腹节长(X₉)、第6腹节宽(X₁₀)、第6腹节高(X₁₁)、尾节长(X₁₂)、尾扇长(X₁₃)13个形态性状,通过通径分析和灰色关联分析等方法研究了各性状之间的关系。结果显示,雌性鹰爪虾各生物学指标均大于雄性,雌、雄群体各性状之间均呈极显著正相关关系(P<0.01),体长(X₂)与体重的相关系数均最大(分别为0.972和0.969);通径分析和决定系数分析发现,雌、雄群体体长(X₂)对体重的直接影响和直接决定系数均最大(通径系数分别为0.443和0.519),雌、雄群体对体重间接作用最大的形态性状分别为第1腹节宽(X₇)(作用系数之和为0.750)和尾节长(X₁₂)(作用系数之和为0.887),雌性群体体长(X₂)和头胸甲高(X₅)的共同决定系数最大(0.167),雄性群体全长(X₁)和体长(X₂)的共同决定系数最大(0.248)。采用逐步回归法建立雌、雄群体形态性状与体重的多元回归方程分别为Y₁=–14.563+0.133X₂+0.374X₇+0.282X₅+0.225X₁₃(R₂=0.978)、Y₂=–7.947+0.092X₂+0.309X₄+0.203X₁₀+0.036X₁–0.087X₁₂(R₂=0.980)。雌性群体形态性状与体重的关联系数平均值在0.868~0.941之间,雄性群体的平均值在0.793~0.906之间,从同一形态性状来看,雌性群体与体重关联系数的平均值均大于雄性群体。雌、雄群体体长(X₂)与体重的关联度均为最高。通径分析结果和灰色关联分析结果并不完全相同,综合比较分析得出,在进行鹰爪虾选育时,雌、雄群体以体长(X₂)作为主要选择性状,雌性群体辅助选择头胸甲高(X₅)和第1腹节宽(X₇);雄性群体辅助选择头胸甲宽(X₄)和全长(X₁)。     

密度和垄作方式对金铁锁产量和质量的影响

为确定金铁锁适宜的种植密度和垄作栽培方式,采用正交设计L16(43),研究沟宽(A)、垄宽(B)、密度(C)对金铁锁产量和质量的影响。结果表明,不同密度和垄作方式对金铁锁产量和质量的影响不同,3个因素对金铁锁根产量影响依次为C、A、B,对质量的影响依次为C、B、A。综合考虑产量和质量,金铁锁最佳垄作栽培方式为沟宽20～30 cm,垄宽60～80 cm,密度8 cm×10 cm或8 cm×15 cm。     

Genome-wide identification of WOX gene family in apple and a functional analysis of MdWOX4b during adventitious root formation

The plant-specific WUSCHEL-related homeobox(WOX) genes are crucial for plant growth and development.Here,we systematically identified the MdWOX gene family in apple at the genome-wide level,and analyzed the phylogenetic relationships,conserved motifs,gene structure,and syntenic relationships of the MdWOX genes.A total of 18 MdWOX genes were identified and phylogenetic analysis placed them into three clades.The phylogenetic relationships among the WOXs were further supported by the analyses of ge...     

Alteration of apoptotic susceptibility and bcl-2 gene in malignant transformation of human bronchial epithelial cells

AIM: To demonstrate the susceptibility of cell apoptosis varies during the progress of cell malignant transformation from human being in vitro. METHODS: A SV₄₀T-transfected human bronchial epithelial immortalized cell line (called M) was selected in this work, which has acquired some characteristics of malignant transformation at the later passage. The alterations of apoptosis and bcl-2, P53 genes between early and later passage of M cells were investigated by means of TDT labeling in situ, chromosome FISH, RNA and protein testing, etc. RESULTS: Incidence of apoptosis induced by cis-platin was significantly lower in later than in early passages of M. Levels of bcl-2 mRNA and protein in later passages were higher than early passages of M, and overexpression of bcl-2 was accumulated following the development of cellular malignancy. P53 protein level was as high in early as in later passages. CONCLUSION: Overexpression of bcl-2 decreases the cellular sensitivity to apoptotic inductors plays an important role during progress of carcinogenesis in human bronchial epithelial cancers. The inactivation of P53 protein in the SV₄₀-T transfected M cell line may be one of reasons of bcl-2 overexpression, but not associated with the accumulation of bcl-2 expressed level during cell transformation.     

Inducible nitric oxide synthase and arterial pressure regulation

AIM and METHODS:To clarify the role of inducible nitric oxide synthase (iNOS) in the regulation of blood pressure,in the present study, we examined the effect of aminoguanidine (AG), a selective inhibitor of iNOS on the hemodinamical response of Dahl salt-sensitive (DS) and Dahl salt-resistant (DR) rats to low (0.3%) or high (8%) sodium chloride (NaCl) infusion by chronical in vivo hemodynamic experiment, and the effect of NaCl or NaCl plus AG infusion on urinary nitrate (NO₃)/nitrite (NO₂), the end product of nitric oxide (NO), excretion by Greiss Reaction. Furthermore, NOS activity assay was also carried out to probe the effect of NaCl and AG on calcium-dependent or independent NOS activity in renal tissue. RESULTS:1. High or low NaCl-infused DR rats and low NaCl-infused DS rats have no hemodinamical response to AG, however, the hypertensive effect of high NaCl (8%) infusion on DS rats were greatly amplified by co-infusion of AG. 2. Administration of high NaCl significantly elevated the iNOS activity of renal tissue, and greatly increased urinary NO₃/NO₂ excretion. CONCLUSION:Inducible NOS is an important modulator of arterial pressure, especially in case of higher blood pressure.     

民勤绿洲现代农业发展对策

民勤绿洲是以农业为主的经济实体,绿洲生态环境局部好转、总体恶化,可持续发展形势严峻,在绿洲内部进行现代农业生产,尤为重要和关键。本文分析了民勤绿洲农业发展的优劣势和现代农业发展中存在的问题,提出了民勤绿洲现代农业发展的具体对策,以期为当地可持续发展提供科学依据。     

35个粳稻品种SSR指纹图谱的构建及遗传相似性分析

用68对SSR引物扩增了35个粳稻品种(系)的基因组DNA,结果有46对引物在35个品种间具有稳定多态性.有6个品种可用单一特异的SSR标记加以识别,其余29个品种则需要不同的SSR指纹组合才能识别.用12对核心引物构建的SSR指纹图谱能将35个粳稻品种逐一区别开来.35个粳稻品种间遗传相似系数的变异范围为0.27～0.98.采用类平均法进行聚类分析,在相似系数0.82处,可将35个粳稻品种分为4类.聚类分析结果基本上反映了依据系谱分析的品种间亲缘关系.