氟磺胺草醚降解菌的分离鉴定及生长特性研究

氟磺胺草醚广泛应用于大豆田防除阔叶杂草,其长残留问题十分严重,微生物降解是解决氟磺胺草醚残留问题的有效途径。利用高压富集的方法,从长期施用氟磺胺草醚的田间土壤中,分离筛选出6株能够以氟磺胺草醚为唯一碳源生长的降解菌,其中一个菌株在查氏液体培养基中培养5d,对40mg a.i./L氟磺胺草醚的降解率为92.13%。通过形态特征鉴定并对该菌株18S rRNA的部分序列进行基因测序,对其在系统发育分类学上的地位加以分析,同时研究环境条件对其生长的影响。结果表明,该菌株为真菌,初步鉴定为黄曲霉(Aspergillus flavus),实验室命名为TZ1985。菌株TZ1985最适生长温度为25℃,最适培养基pH值为7.0,生长最适葡萄糖含量为0.6%,生长最适氟磺胺草醚的浓度是10mg a.i./L。     

Modulation of broilers’ caecal microflora and metabolites in response to a potential probiotic Bacillus amyloliquefaciens

Studies have found that a dietary supplement of Bacillus amyloliquefaciens improved the growth performance, increased the nutrient digestibility of hosts and modulated the intestinal microflora. A total of 360 1‐day‐old Ross broilers were randomly divided into three treatments: a control group with a basal diet, an antibiotic group with a basal diet and added colistin sulphate, and a probiotics group with a basal diet and added Bacillus amyloliquefaciens. The HiSeq high‐throughput sequencing analysis of 16S rRNA was used to investigate the differences in birds’ caecal microflora, and metabolomics was used to analyse changes in caecal metabolites. Results showed that the supplementation of Bacillus amyloliquefaciens significantly improved the BW and ADG compared with the control birds. Results of sequencing indicated that (i) 645, 670, 596 unique operational taxonomic units (OTUs) were found in birds supplemented with Bacillus amyloliquefaciens on day 7, 21 and 42, separately, (ii) due to the diversity and relative abundance of the birds’ caecal microflora, the OTUs of the caecal microflora clustered according to age and treatment, except on day 42, (iii) among the six predominate families (Ruminococcaceae, Lachnospiraceae, Enterobacteriaceae, Erysipelotrichaceae, Lactobacillaceae and Rikenellaceae), the supplementation of Bacillus amyloliquefaciens significantly increased Enterobacteriaceae on day 42, (iv) Bacillus amyloliquefaciens increased the relative abundance of Faecalibacterium and Ruminococcus on day 21, increased the Faecalibacterium and Blautia and decreased the Ruminococcus on day 42. The metabolomics of caecal metabolites showed that the dietary Bacillus amyloliquefaciens changed the caecal metabolites involved of amino acid metabolism and glyceride metabolism, and the antibiotics changed the caecal metabolites that were related to carbohydrates and amino acid metabolism on day 21.     

上海市猪圆环病毒2型全基因组的克隆与序列分析

参照国外发表的猪圆环病毒2型(Porcine circovirus type 2,PCV-2)全基因组序列,设计合成了1对特异性引物,从上海市临床病料中提取PCV-2基因组DNA,进行PCR全基因扩增。回收PCR产物,将其插入pMD18-T载体,并对筛选出的阳性质粒进行测序。应用DNAStar序列分析软件,对所测PCV-2序列与GenBank中登录的国内外PCV-2毒株进行同源性比较。结果显示,PCV-2上海株与国内外毒株的核苷酸同源性高达95.0%～100%。进化树分析结果显示,其中9株PCV-2病毒属于PCV-2b亚型,3株PCV-2病毒属于PCV-2a亚型,且9株PCV-2b亚型毒株部分核苷酸位点显示其属于强毒力毒株。研究表明,上海市PCV-2感染以PCV-2b亚型为主,且氨基酸位点表明其具有较高的毒力。     

马泰勒虫不同PCR检测方法的比较

为寻求一种快速、有效的马泰勒虫PCR检测方法，用Bec-UF2、Equi-R；EMA-1F、EMA-1R两对引物对56份马血液样本中马泰勒虫的核蛋白体基因和表面蛋白基因进行了常规PCR方法检测，用EMA-5、EMA-6；EMA-7、EMA-8两对引物对56份马血液样本中马泰勒虫的表面蛋白基因进行了PCR和套式PCR方法检测。结果显示，以Bec-UF2、Equi-R为引物的PCR方法的阳性检出率为57．1％（32／56），以EMA-5、EMA-6；EMA-7、EMA-8为引物的套式PCR方法的阳性检出率为51．8％（29／56），以EMA-1F、EMA-1R为引物的PCR方法的阳性检出率为17．9％（10／56）。结果表明，以Bec-UF2、Equi-R为引物的常规PCR方法为检测马泰勒虫的最佳方法。     

高邮鸭和金定鸭胸肌早期发育及MyoD1基因表达分析

 
采用qPCR分析生肌调节因子MyoD1基因在高邮鸭和金定鸭胚胎期及初生早期(13、17、21、25、27胚龄和出雏后7日龄)胸肌发育中的表达模式以及与胚胎和胸肌发育的相关性。结果表明,MyoD1 mRNA在两个品种鸭胸肌早期发育中表现出一致的表达规律,均呈“波浪形”,在13胚龄时表达量相对较高,17胚龄时下降,21胚龄时上升到最高,随后下降,出雏后又维持较高水平;品种间比较结果显示除了在25胚龄时金定鸭胸肌中MyoD1 mRNA表达量稍低于高邮鸭,在其他所检测的胚龄/日龄中,金定鸭胸肌中MyoD1 mRNA表达量均高于高邮鸭胸肌中的表达量(P>0.05);高邮鸭胸肌MyoD1 mRNA表达与胚胎和胸肌发育无显著相关性,而金定鸭胸肌中MyoD1 mRNA的表达与其胚胎和胸肌发育呈强负相关(P胚重=0.048;P胸肌重=0.006)。MyoD1基因参与鸭胚胎期及出雏早期胸肌的发育,胸肌中MyoD1基因表达分析研究为进一步深入研究MyoD1基因在胚胎期胸肌发生过程及其调控机理中的功能提供一定的理论依据     

NaC1和Na2C03胁迫对水稻籼粳杂交后代群体发芽与幼苗生育的影响

针对内陆苏打盐碱土pH值高的特点,分别利用0.30mmol·L-1NaC1和0.15mmol·L-1Na2CO3作为胁迫条件,研究了籼梗杂交形成的DH群体的芽期和苗期相关性状的伤害率.结果表明:各性状盐碱伤害率株系间存在明显分离,且Na2C03伤害率明显高于NaC1.NaC1胁迫条件下芽期和苗期伤害率平均值为8.70和24.93,Na2CO3胁迫条件下分别为19.38和59.73.芽期和苗期的综合伤害率分为高、中、低3个等级,比较发现芽期和苗期的耐盐碱性并不一致.NaC1和Na2CO3伤害差株系间存在很大差异,说明不同株系对碱性胁迫反应存在遗传差异,芽期和苗期的伤害差分为4个级别,其中芽期和苗期分别有36和30个株系的盐碱伤害差较小,平均值分别为-0.33和23.15.这些株系属于碱低敏感型,从中筛选出15个芽期和苗期对碱性环境均相对不敏感株系,两个时期的盐碱伤害差平均数分别为-0.62和23.03.籼粳杂交后代在耐碱性上表现出遗传分离,说明水稻存在抵御高pH胁迫的基因调控系统,通过遗传重组可以获得耐碱性强的品种.     

Bt转基因抗虫棉田昆虫群落结构研究

选用3个转Bt基因抗虫棉品种DP99B、20B、1560BG和2个非抗虫棉对照品种鄂杂棉1号、湘杂棉2号,比较研究了不同棉花群体中昆虫群落结构特征。结果表明,在未采取任何防治措施的情况下,3个转Bt基因抗虫棉对棉铃虫种群,尤其是在棉花生育前期有很好的抑制作用;同时对其他鳞翅目害虫种群也有一定控制效果,这使得棉蚜、棉叶蝉、烟粉虱等刺吸式害虫上升为主要害虫。但抗虫棉棉田昆虫群落、害虫亚群落以及天敌亚群落的多样性、均匀性均较对照棉田小,而优势集中性比对照棉田高,反映出抗虫棉棉田昆虫群落结构稳定性较差。相对来说,DP99B和20B抗虫性能较好,其棉田昆虫群落结构也比较稳定。因此,转Bt基因抗虫棉的大面积应用中,除了要关注抗毒性棉铃虫的产生和危害以外,还应特别注意其他可能上升为主要害虫(如棉蚜、棉叶蝉、烟粉虱等)的防治工作。     

西南冷凉高地苹果园土壤养分状况分析

为了解我国西南地区冷凉高地苹果园土壤养分状况,对昭通市70个具有代表性的果园土壤进行实地取样研究,分析了昭通苹果园土壤养分存在的问题。结果表明：西南冷凉高地苹果园土壤整体呈酸性,有机质含量达到我国丰产优质果园水平;果园土壤大量营养元素氮、磷和钾含量比较丰富,中量元素交换性钙和交换性镁含量处于高量水平,微量元素有效铁、有效锌、有效铜和有效锰含量都存在过量现象,果园土壤养分之间易出现拮抗现象,且养分分布不均。生产实践中应加强测土配方施肥技术的研究与应用,充分利用丰富的土壤肥力资源,提高土壤养分利用率,从而为西南冷凉高地苹果提质增效,产业升级奠定基础。     

Fabrication of hydrophobic/oleophilic cotton fabric by mussel-inspired chemistry for oil/water separation

A straightforward approach was proposed to modify cotton fabric for oil/water separation based on musselinspired reaction. The poly(DMA-Octadecyl acrylate) was designed to contain key chemical constituents present in mussel adhesive proteins by free radical polymerization of dopamine hydrochloride and octadecyl acrylate, which strongly adsorbed to fabric substrates, providing a special surface for fabric. The chemical structure, surface topography, and surface wettability of the fabric were characterized. The results showed that as-prepared cotton fabric displayed a high CA of >150° when dripped water droplets were on the modified fabric surface, and the oil contact angle (OCA) was close to 0°, it had excellent potential to be used in practical applications and has created a new method of fabric modification for oil/water separation.     

华北平原冬小麦-夏玉米轮作体系中标记15N的去向及残效

A field experiment was conducted to investigate the fate of ¹⁵N-labeled urea and its residual effect under the winter wheat (Triticum aestivum L.) and summer maize (Zea mays L.) rotation system on the North China Plain. Compared to a conventional application rate of 360 kg N ha^-1 (N360), a reduced rate of 120 kg N ha^-1 (N120) led to a significant increase (P < 0.05) in wheat yield and no significant differences were found for maize. However, in the 0-100 cm soil profile at harvest, compared with N360, N120 led to significant decreases (P < 0.05) of percent residual N and percent unaccounted-for N, which possibly reflected losses from the managed system. Of the residual fertilizer N in the soil profile, 25.6%-44.7% and 20.7%-38.2% for N120 and N360, respectively, were in the organic N pool, whereas 0.3%-3.0% and 11.2%-24.4%, correspondingly, were in the nitrate pool, indicating a higher potential for leaching loss associated with application at the conventional rate. Recovery of residual N in the soil profile by succeeding crops was less than 7.5% of the applied N. For N120, total soil N balance was negative; however, there was still considerable mineral N (NH₄⁺-N and NO₃^--N) in the soil profile after harvest. Therefore, N120 could be considered agronomically acceptable in the short run, but for long-term sustainability, the N rate should be recommended based on a soil mineral N test and a plant tissue nitrate test to maintain the soil fertility.