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71.
风成黄土是研究古气候变化的良好载体,在全球陆地分布广泛,而不同区域地理环境差异显著,其记录气候变化的机制亦有所不同。以色列南部黄土区地处亚热带沙漠边缘,为探究该区域黄土磁性特征及其对区域环境的响应机制,对内盖夫沙漠边缘黄土区进行野外考察并测试系统环境磁学及粒度参数。结果表明,Har Keren(HK)剖面中磁性矿物主要为碎屑磁铁矿和磁赤铁矿,磁性矿物含量较少,磁性颗粒主要为粗单畴(SD)和多畴(MD),磁性特征与中国西北干旱区黄土较为相似。HK剖面常温磁学参数整体变化范围较小,仅在剖面亚表层有所升高,可能是受现代成土作用影响。HK剖面中值粒径自底部至顶部呈减小趋势,但粒度整体偏粗,其频率分布曲线显示为正偏态,分选较差,反映出多种搬运方式的混合特征,与典型风成黄土有所差异。  相似文献   
72.
Parasites are thought to increase the risk of host extinction, but their dynamics in endangered species have not been well investigated. The free-living European bison population in Bia?owie?a Forest has recently been massively invaded by a blood-sucking nematode, Ashworthius sidemi. This nematode originated in Asia and was probably transmitted to Europe with the introduction of the sika deer. Here, we investigate the impacts of genetic factors (the Major Histocompatibility Complex class II genes responsible for extracellular parasite recognition) and management practices (supplementary feeding affecting winter population density) on the intensity of A. sidemi infections in bison. All but two out of 110 animals investigated between 2005 and 2009 were infected with A. sidemi, and the intensity of infection increased significantly with time. Due to a severe population bottleneck experienced by the bison, only four class II DRB alleles are retained in the Bia?owie?a population. We found that despite high sequence divergence, neither any of the alleles nor DRB heterozygosity was significantly associated with infection intensity. We did find, however, that winter density of bison herds was positively associated with infection intensity. Winter bison population densities were in turn predicted by the intensity of supplementary feeding.  相似文献   
73.
[目的]弄清河流弧菌对海水贝类的危害性,为预防该菌所引起的水产动物疾病提供参考依据。[方法]使用TCBS培养基从文蛤生物体内分离出1株弧菌,对其进行鉴定、致病性以及药敏试验。[结果]分离的弧菌为革兰氏阴性,根据其生理生化特性可初步鉴定为河流弧菌。动物试验结果表明,这株河流弧菌对昆明小鼠具有较强的致病性。河流弧菌对四环素、环丙沙星、头孢曲松、氟哌酸、先锋赛、先锋必、丁胺卡那高度敏感,对安卡青霉素、青霉素G、先锋霉素V、利福平耐药。[结论]临床上,应将选用四环素、环丙沙星、头孢曲松、氟哌酸、先锋赛、先锋必、丁胺卡那作为治疗河流弧菌的首选药物。  相似文献   
74.
为了适应兽医临床的简陋条件和在分散的养殖场进行联合抗药性监测,按照药敏试验中试管稀释法原理研制灵敏、准确、稳定、操作简单、无需专门仪器设备的原位吸管式药敏检测盒,4-7h快速判断11种药物对目标病原菌敏感性,指导临床用药,并在肉鸡养殖中进行了应用;同时联合六和、中慧、正大、九联、民和、春雪、益生等省内大型养殖企业,借助企业的技术体系建立山东省动物源病原菌抗药性监测网络、数据库、菌种库,利用网络技术对抗药性数据进行收集、汇总,并实现网上查询,对了解跟踪山东省动物源病原茵抗药性发展规律具有重要参考价值。  相似文献   
75.
[目的]为蒙古鲌的科学用药提供参考,促进其养殖业的发展.[方法]对蒙古鲌进行了一些常用药物的敏感性试验.[结果]蒙古鲌对氯氰菊酯十分敏感,48 h TLM为0.072 mg/L,最低致死浓度范围为0.063~0.069 mg/L,安全浓度为0.021 6 mg/L.蒙古鲌鱼苗对甲苯咪唑、敌百虫、硫酸铜、强氯精、聚维酮碘均不敏感.以安全浓度为标准,蒙古鲌鱼苗对氯氰菊酯的敏感性大于辛硫磷.[结论]该研究可为更好保护和开发蒙古鲌资源提供依据.  相似文献   
76.
从自然死亡家蚕分离得到一菌株zl1-r,回复感染确定其为家蚕病原菌。对该菌进行形态学观察及16SrRNA序列分析,结果显示该病原菌为气单胞菌属(Aeromonasspp.)。药敏试验结果显示,该病原菌对庆大霉素,强力霉素,链霉素,环丙沙星,壮观霉素,卡那霉素,氧氟沙星,多粘菌素有很强的敏感性,对交沙霉素,青霉素,新霉素,阿奇霉素,罗红霉素中度敏感,对头孢唑啉,磺胺甲基异哑唑不敏感,对乙酰螺旋霉素,氨苄西林,头孢拉定片,有耐药性。  相似文献   
77.
AIM To investigate the potential associations between the single nucleotide polymorphisms (SNPs) of long noncoding RNA (lncRNA) H19/HOTAIR and the susceptibility to gastric carcinoma, especially to Epstein-Barr virus (EBV)-associated gastric carcinoma (EBVaGC). METHODS Peripheral blood samples from 65 cases of EBV-negative gastric carcinoma (EBVnGC), 50 cases of EBVaGC and 115 cases of healthy people were collected. A total of 4 TagSNPs, H19 rs3024270 and rs3741219, as well as HOTAIR rs4759314 and rs874945, were selected. The Taq-Man MGB allele typing kit was used to detect the genotype of each SNP locus, and the experimental results were statistically analyzed. RESULTS (1) There were significant differences of both genotypic and allelic frequencies at H19 rs3024270 locus between gastric carcinoma group and control group (P<0.05). Individuals carrying the G allele at H19 rs3024270 locus had significantly low risk of gastric carcinoma (P<0.01), indicating that the G allele was protective. (2) People with the GG genotype at HOTAIR rs4759314 locus had significantly high risk of gastric carcinoma (P<0.05). Carrying the G allele increased the risk of gastric carcinoma, which indicated that the risk gene for gastric carcinoma might be the G allele. (3) No significant difference of the genotypic and allelic frequencies at H19 rs3741219 and HOTAIR rs874945 loci between gastric carcinoma group and control group was observed (P>0.05).(4) The G allele frequency at HOTAIR rs4759314 locus in EBVaGC group was significantly higher than that in EBVnGC group. However, no difference of the other 3 SNPs was found between EBVaGC group and EBVnGC group (P>0.05). CONCLUSION The SNPs at H19 rs3024270 and HOTAIR rs4759314 loci are related to the risk of gastric carcinoma, but not significantly related to the risk of EBVaGC.  相似文献   
78.
奶牛乳腺炎是危害奶牛养殖业最常见的疾病之一,给奶牛生产造成巨大的经济损失。其乳腺防御机理、发病机理虽取得了一定的研究成果,但深层次的一些问题仍然未能弄清楚,在这方面还需继续进行大量的研究工作。现就国内外奶牛乳腺自我防御方面的一些机理进行讨论,从乳汁血液当中的免疫活性细胞、体液因子、细胞因子等对乳腺防御方面的功能作详尽的叙述,尤其对泌乳周期中各种白细胞群的分布、功能以及影响奶牛围产期阶段免疫机能下降的一些因素作了分析,对了解和预防奶牛乳腺炎的发生具有一定的参考和应用价值。  相似文献   
79.
In countries like Spain or France, quarantine rules force researchers to evaluate the resistance to Sharka (Plum pox virus, PPV) in controlled, isolated conditions. This evaluation method shows important limitations resulting from the management of plants in the controlled conditions, grown in pots with artificial cycles of growth in the greenhouse and cold chamber, alternately. The objective of this study is to analyse different factors that affect the efficiency of the method of evaluation of PPV resistance in controlled greenhouse conditions. The cultivars evaluated as model genotypes were the resistant ‘Stark Early Orange’ and the susceptible ‘Real Fino’ apricot. Furthermore the ‘GF305’ peach was used as a susceptible control. The different studied factors were the inoculation protocol (rootstock or variety inoculation), the grafting success (depending on inoculation method, rootstock–variety combination and date of grafting), and the efficiency of the process in each artificial cycle of growth. Results showed that rootstock inoculation was more effective than inoculation of the variety. As rootstock, the ‘GF305’ seedlings were slightly better than the ‘Real Fino’ seedlings in the inoculation process, but they were quite similar in terms of effectiveness in the evaluation and grafting process. Grafting can be carried out in spring or autumn without having important differences. The global efficiency of the evaluation process was much higher with rootstock inoculation.  相似文献   
80.
In the United States, fall armyworm, Spodoptera frugiperda (J. E. Smith) (Lepidoptera: Noctuidae), is a target species of transgenic corn (Zea mays L.) expressing pyramided Bacillus thuringiensis proteins. In 2011, a total of 150 F2 two-parent families of S. frugiperda were established using single-pair matings of feral individuals collected from three locations in Louisiana and Florida. The objective of this study was to determine the susceptibility of these field derived families of S. frugiperda to a pyramided Bt corn hybrid containing Agrisure®Viptera™ 3111 traits. For each F2 family, 96 neonates were assayed on leaf tissue of Agrisure®Viptera™ 3111 corn in the laboratory. None of the 150 families survived for 7 days on leaf tissue of the Bt corn plants. The results demonstrate that the field populations of S. frugiperda collected from Louisiana and Florida were susceptible to the pyramided Bt corn product containing Agrisure®Viptera™ 3111 traits. The data generated in this study can be used as baseline data for resistance monitoring.  相似文献   
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