Brenneria spp. and Rahnella victoriana associated with acute oak decline symptoms on oak and hornbeam in Iran

Decline diseases of forest trees are complex syndromes not attributable to single causal factors. In Iran, symptoms of decline disease have been observed in a number of native forest species including Quercus castaneifolia (chestnut‐leaved oak), Q. brantii (Persian oak) and Carpinus betulus (hornbeam). The symptoms are prevalent in the northern forests and the Zagros mountain forests. There are parallels between the disease in Iran and acute oak decline (AOD) reported in the UK, specifically the presence of weeping cankers, which have been attributed to a polybacterial complex wherein Brenneria goodwinii is considered a key necrogen. Based on the AOD symptomatology, and as a first step towards discovering potential causal agents of the stem weeping symptoms of affected trees in Iran, necrotic tissues were tested primarily for the presence of B. goodwinii. Symptomatic Q. castaneifolia and C. betulus from the Mazandaran Province and symptomatic Q. brantii from Kohgiluyeh and Boyerahmad Province were sampled. Isolation and culture on a selective medium yielded uniform bacterial colonies. Isolates were characterized using phenotypic and genotypic (DNA sequencing) tests. The isolates were phenotypically identical to members of Pectobacteriaceae and Yersiniaceae, specifically Brenneria and Rahnella spp. The nucleotide sequences of the 16S rRNA and housekeeping genes gyrB, infB and atpD (MLSA) amplified via PCR demonstrated that the isolates from the trees in Iran were indeed B. goodwinii, B. roseae subsp. roseae, Rahnella victoriana and an unknown species of Brenneria. Most bacteria isolated from non‐symptomatic trees were Gram‐positive, and Pseudomonas spp. were dominant, but bacterial species isolated from the diseased trees were not detected in healthy trees. Hypersensitivity response tests were positive, but inoculation on saplings was more variable with internal necrosis developing only once in the test period. Therefore, further testing is required. This is the first report of the incidence of B. goodwinii, B. roseae subsp. roseae, R. victoriana and Brenneria sp. associated with acute oak decline‐like symptoms on Q. castaneifolia, Q. brantii and C. betulus across the western forests of Iran and in the world.     

7种稀土小檗碱配合物对4种农作物病菌的抑菌性及急性毒理性的研究

研究开发了7种新型稀土配合物。使用差热热重和红外表征了配合物,采用最低抑菌浓度实验,研究了配合物对4种（番茄溃疡病菌、向日葵菌核病菌、尖孢镰刀菌和胡萝卜黑斑病菌）农作物病原菌的敏感性;采用急性经口毒性和急性经皮毒性试验,考察其急性毒性。7种配合物均为低毒性药物,并且抑菌效果好。对向日葵菌核病菌最低抑菌浓度均为0.125 mg/mL。对番茄溃疡病菌抑菌效果最好的是Ce(NO3)3(B)3、Gd(NO3)3(B)3,最低抑菌浓度是0.125 mg/mL。对尖孢镰刀菌抑菌性最好的是La(NO3)3(B)3、Gd(NO3)3(B)3和Y(NO3)3(B)3,最低抑菌浓度是0.5 mg/mL。对胡萝卜黑斑病菌抑菌性最好的是Gd(NO3)3(B)3,最低抑菌浓度是0.5 mg/mL。结果表明7种新型稀土小檗碱配合物是一类广谱、高效、低毒的杀菌剂。     

栀子苷对小鼠急性肺损伤保护机制的研究

为了探究栀子苷能否对脂多糖(LPS)致小鼠急性肺损伤发挥保护作用及其潜在的作用机制。雄性Balb/c小鼠,于鼻腔滴注LPS前1 h腹腔注射栀子苷(50 mg/kg)或者地塞米松注射液(5 mg/kg),滴注LPS 24 h后,采用酶联免疫吸附法(ELISA)测定小鼠支气管肺泡灌洗液(BALF)中肿瘤坏死因子-α(TNF-α)、白介素(IL)-6和IL-10的浓度。通过细胞分类计数法分析BALF中细胞总数、巨噬细胞和中性粒细胞的变化。采用蛋白印迹法(Western-blot)分析核转录因子-κB（NF-κB）信号转导通路激活的程度。腹腔注射栀子苷可降低小鼠肺干湿比（W/D值）;改善肺组织病理学结构,减少肺泡出血和炎性细胞浸润且伴有髓过氧化物酶活性下降;抑制促炎性细胞因子TNF-α和IL-6分泌,促进抗炎性细胞因子IL-10生成。栀子苷通过缓减炎症反应保护LPS致小鼠急性肺损伤,其机制可能与阻止NF-κB信号转导通路的激活有关。     

纳米氧化锌和纳米二氧化钛对尾草履虫急性毒性效应的比较研究

[目的][方法] 本研究以原生动物尾草履虫（Paramecium caudatum）为实验对象, 对目前广泛应用的两种纳米材料,纳米二氧化钛（TiO2）和纳米氧化锌（ZnO）的24小时急性毒性进行了比较研究,分析了草履虫在两种纳米材料胁迫下抗氧化酶活性的改变,并结合两种纳米材料的超微形态,探讨了纳米材料毒性效应的机制,为两种纳米材料的环境毒性监测与评价提供依据。[结果]结果显示：对尾草履虫的24小时半数效应浓度(24h-EC50)分别为51.580mg·L-1（TiO2）、0.444mg·L-1（ZnO）;最低有影响浓度(24h-LOEC)分别为1.712mg·L-1（TiO2）、0.352mg·L-1（ZnO）;以EC50浓度24小时胁迫尾草履虫,获得抗氧化酶活性改变为：超氧化物歧化酶(SOD),过氧化氢酶(CAT)和过氧化物酶(POD)活性与对照组相比有不同程度的改变,经成对检验分析,两种纳米材料对尾草履虫的POD酶表现出较为明显的抑制作用。[结论]上述结果表明：纳米氧化锌对草履虫的24小时急性毒性大于纳米二氧化钛,这与纳米氧化锌对草履虫抗氧化酶的抑制作用更强,以及纳米氧化锌(30nm)的超微形态相较于纳米二氧化钛(25nm)更加纤细和尖锐有关;本研究获得的24小时急性毒性指标可用于监测和评价两种纳米材料的环境毒性,并为纳米材料的环境容量和生态安全阈值确定提供参考。     

1株猪丹毒杆菌的分离与鉴定

为确定导致安徽和县某猪场猪只发病的病原,从该猪场送检病料(心、肺、脾、肝)中分离并纯化细菌,根据其形态特征、PCR鉴定及生化试验结果,确诊为猪丹毒杆菌。spa A基因序列分析结果显示该菌与猪丹毒杆菌G4T10(Gen Bank登录号:KF150604.1)有99%的同源性。全自动生化反应报告该菌为丹毒丝菌的概率高达95%。小鼠攻毒试验表明,试验组小鼠在腹股沟皮下注射该菌后,4 d内全部死亡;死亡小鼠剖检可见全身败血性出血,各脏器均有病变,从死亡小鼠的血液、心、肝、脾、肺等组织中分离到与该感染菌株形态特征完全一致的细菌。药敏试验结果表明,该菌对β-内酰胺类和大环内酯类抗生素敏感,对链霉素、卡那霉素、四环素、多西环素、林可霉素和磺胺异恶唑耐受。     

Adhesion of bone marrow stromal cell in children with acute lymphoblastic leukemia

AIM and METHOD: The adhesion behavior of bone marrow stromal cells(BMSC) in children with acute lymphoblastic leukemia(ALL) to bone marrow mononuclear cells(BMMC) and Raji cells were investigated by MTT method. The expression of adhesion molecules ICAM-1 and VCAM-1 were detected by flow cytometry. RESULTS: The adhesion ability of BMSC in acute period of ALL to BMMC was lower than that of control group. The adhesion ability of BMSC in long term remission period of ALL to Raji cells higher than that of control group. The expression of ICAM-1 on the surface of BMSC in acute period of ALL is much lower than that of control group. CONCLUSIONS: The adhesion of BMSC to BMMC or tumor cells in children with ALL was abnormal. The abnormal adhesion behavior might be partially due to the changed expression of adhesion molecules on BMSC.