落叶松轻基质网袋扦插育苗研究

[目的]探讨不同扦插基质对落叶松扦插生根的影响。[方法]采用轻基质和河沙作为落叶松扦插的基质,对落叶松插穗的最长根长、生根数量、偏根率和生根率等4个指标进行调查分析,并探讨了不同无性系轻基质网袋扦插的生根情况。[结果]2种基质中落叶松最长根长和生根率2个指标达到极显著差异,河沙基质中落叶松最长根长是轻基质中的1.50倍;河沙基质中落叶松生根率是轻基质的1.97倍;2种基质中落叶松生根数量的差异不显著;在偏根率方面,轻基质处理要低于河沙基质处理,但两者差异未达到显著水平。落叶松无性系间扦插生根率存在显著差异,最高生根率达95.56%。[结论]河沙作为扦插基质的效果要优于轻基质作扦插基质;筛选优良无性系可显著提高落叶松轻基质扦插的生根率。     

棉花育种中黄萎病抗性连锁SSR标记辅助选择的效果

利用长江流域棉花(Gossypium spp.)育种重要亲本苏棉12和荆55173(感黄萎病)与抗黄萎病资源Sicala V1和中21373配制两套感病×抗病杂交组合(苏棉12×Sicala V1和荆55173×中21373),在其杂交组合的自交子代群体中挑选与黄萎病抗性相关的9个SSR(Simple sequence repeat)标记实施分子标记辅助选择(Marker-assisted selection,MAS)育种。结果表明,通过单标记选择,8个SSR标记的aa与AA两种基因型个体间的黄萎病校正病情指数(Correction disease index,CDI)差异达到极显著或者显著水平。利用多元逐步回归分析得到的单标记、双标记以及多标记3种筛选方法的效果,结果表明合理采取多个有效标记同时筛选能够提高选择的准确度。     

生防菌与茄病镰刀菌在黄瓜根际动态变化

应用荧光定量PCR和稀释分离法检测了枯草芽孢杆菌Bacillus subtilis和木霉菌Trichoderma spp.与茄病镰刀菌Fusariumsolani f.sp.cucurbitae在黄瓜根际动态变化及其对黄瓜根腐病的防治效果。结果表明,施用500×木霉菌肥、100×枯草芽孢杆菌7d后对黄瓜根腐病的防效分别为100%和92.5%,14和28d的防效分别为96.71%、86.76%和85.35%、79.24%;100×枯草芽孢杆菌初始拷贝数为130787 copys/μL,7d内枯草芽孢杆菌拷贝数下降到51161 copys/μL,14和28d时数量开始上升到295139和680556 copys/μL。木霉菌肥的变化趋势与枯草芽孢杆菌相同;用枯草芽孢杆菌和木霉菌肥防治黄瓜根腐病后,茄病镰刀菌变化趋势一致,初始拷贝数分别为2.61和15.34 copys/μL,7d内茄病镰刀菌DNA拷贝数增加明显,100×枯草芽孢杆菌和木霉菌DNA拷贝数分别为11.22和20.9 8copys/μL,之后茄病镰刀菌数量保持平稳。经过稀释分离法分离2种生防菌和茄病镰刀菌的数量,变化趋势与荧光定量PCR检测趋势相似。因此使生防菌快速定殖是提高其对土传病害防治效果的重要因素之一。     

Granulomatous lesions in a wild mullet population from the eastern Ligurian Sea (Italy): mycobacteriosis vs. pseudotuberculosis

Mycobacterium spp. and Photobacterium damselae subsp. piscicida are recognized as the most frequent causative agents of granulomatous lesions in fish. Although frequent episodes of mycobacterial infections have been reported in wild fish worldwide, only sporadic cases have been documented to date in Italy. To investigate for the presence of lesions referable to mycobacteriosis and to identify the mycobacterial species involved, a total of 159 wild mullets were fished from the eastern coast of the Ligurian Sea, killed and necropsied. Liver and spleen samples were collected from all fish for histopathological and microbiological analyses. Molecular investigations for identification of Photobacterium damselae subsp. piscicida were performed. Gross examination revealed granulomatous lesions in one animal; microscopically, 42.14% of fish displayed granulomas with various histological features, 19.50% resulted positive at Ziehl–Neelsen staining, and were confirmed as mycobacterial lesions by culture. The identified colonies were characterized as M. fortuitum, M. abscessus, M. flavescens, M. chelonae, M. septicum and M. nonchromogenicum. In all, 35% of animals resulted positive for Photobacterium damselae subsp. piscicida. These data suggest widespread mycobacterial infection also by Photobacterium damselae subsp. piscicida infections in wild fish. Moreover, the pathogenicity of some mycobacterial species, previously considered as saprophytic, was demonstrated.     

The in‐vitro antibacterial effects of organic salts,chemical disinfectants and antibiotics against pathogens of black disease in fairy shrimp of Thailand

The antibacterial effects of organic salts, chemical disinfectants and antibiotics were evaluated on cultures of Aeromonas hydrophila C03, Aeromonas sobria C26, A. sobria C29, Aeromonas caviae C24 and Acinetobacter sp. SH‐94B, the pathogens that cause black disease found in fairy shrimps (Streptocephalus sirindhornae Sanoamuang et al. (2000) and Branchinella thailandensis Sanoamuang, Saengphan & Murugan) of Thailand. The minimal inhibitory concentrations (MICs) of organic salts (sodium chloride and potassium chloride) and antibiotics (oxytetracycline dihydrate, streptomycin sulphate, kanamycin monosulphate, chloramphenicol and ampicillin) were determined using the agar‐dilution method. The effect of chemical disinfectants (sodium hypochlorite and chlorine dioxide) was evaluated by exposing bacteria to different concentrations of these chemicals for different periods of time. Interestingly, all strains were intrinsically resistant to 0.25–3% sodium chloride and potassium chloride. The effect of sodium hypochlorite was greater than that of chlorine dioxide, and 5–20 μg mL^?1 of sodium hypochlorite was sufficient to inhibit the growth of these bacteria, but the exposure time varied, depending on the bacterial species. Of the antibiotics tested, chloramphenicol and oxytetracycline dihydrate completely inhibited the selected strains. Chloramphenicol showed the highest antibacterial effect against all pathogenic species – the MIC and minimal bactericidal concentration (MBC) ranged from 0.8 to 3.1 μg mL^?1 from 3.1 to 6.25 μg mL^?1, respectively. To achieve control of black disease during cultivation of fairy shrimp, data derived from this study can be used as a basis for further toxicity tests in vivo.     

基于文献计量统计分析中国棉花研究学术发展

运用文献计量方法,以SCIE数据库为数据源基础,检索了有关棉花研究的文献,从文献量、学科、期刊、著者和引文等角度进行了统计和分析,以定量数据从侧面反映10多年来中国棉花研究领域学术发展状况,揭示了中国加入WTO后棉花研究领域的蓬勃发展态势,年载文量稳步快速增长,学科研究领域广泛,基础科学研究取得了长足进步,国际交流与合作普遍,形成了较强的棉花研究团队,具有较强的学术研究领军人物,带动了中国棉花学术领域的发展。     

陕西设施蔬菜根结线虫特异性分子检测

为明确陕西设施蔬菜根结线虫的主要种类,利用已报道的花生根结线虫[Meloidogyne arenaria (Neal.) Chitwood]、南方根结线虫[Meloidogyne incognita (Kofold & White) Chitwood]、北方根结线虫(Meloidogyne hapla Chitwood)和爪哇根结线虫[Meloidogyne javanica (Treub)]的特异性引物,对陕西省20个县市区的24个样区的根结线虫进行PCR检测。样品中检测到了南方根结线虫、北方根结线虫、花生根结线虫和爪哇根结线虫,其中南方根结线虫为优势种群,大部分样区为单一种群为害,但个别样区存在2种种群。     

河南省某地区健康人源及动物源肠球菌种属分布及耐药性差异研究

为了解河南省某地区社区健康人源及动物(鸡、猪)源肠球菌种属分布及对多种抗菌药物的耐受情况,以及研究不同来源肠球菌的流行分布和抗菌药物耐药表型特点,本试验应用肠球菌选择性培养基对220份人源及动物源粪便样本进行肠球菌的分离培养,并对分离菌株采用16S rDNA序列分析结合API生化板条进行种属鉴定,纸片扩散法对分离肠球菌进行9种抗菌药物的敏感性检测.肠球菌分离及鉴定结果显示肠球菌总分离率、粪肠球菌分离率及屎肠球菌分离率在人源、鸡源、猪源3种来源间均差异显著(P<0.05):肠球菌总分离率为70.91%(156/220),猪源肠球菌分离率最高(86.00%),人源肠球菌分离率最低(62.63%),且人源与猪源肠球菌分离率差异显著(P<0.018);人源粪便样本中分离率最高的为屎肠球菌(31.36%),鸡源、猪源肠球菌中粪肠球菌分离率最高,分别为28.17%和32.00%.抗菌药物敏感性结果显示肠球菌对多种药物的耐药率在人源、鸡源、猪源3种来源间差异显著(P<0.05),且3种来源肠球菌的多药耐药率差异有统计学意义(P<0.05).人源肠球菌对红霉素(69.35%)、环丙沙星(37.10%)、氨苄西林(19.35%)等抗菌药物耐药率较其他来源的肠球菌要高;鸡源肠球菌对四环素(88.24%)、氟苯尼考(11.76%)、氯霉素(21.57%)等抗菌药物耐药率较其他来源的肠球菌要高;猪源肠球菌对抗菌药物耐药率总体较低,且其多药耐药率(7.84%)也低于人源(35.48%)及鸡源肠球菌(30.19%).提示,健康人及动物粪便样本中肠球菌种属分布不同及对抗菌药物耐药率有差别,并对多种常见抗菌药物耐药率较高,有关部门应加强社区人群及动物等非临床来源肠球菌耐药检查、监测,进而更好的了解中国耐药肠球菌的流行现状,更有效的控制耐药肠球菌的传播.