云南干热河谷旱季车桑子的光合水分生理特性的研究

对云南乡土树种车桑子(Dodonaea viscosa)在云南干热河谷旱季期间的光合水分生理特性进行了研究,研究结果表明:(1)车桑子在严重的缺水胁迫下,所产生的光合午休现象主要是由非气孔限制因素光抑制引起的,其保护光合机构免受损伤;(2)车桑子在严重的缺水胁迫下,即在PAR仍不低于1 300 umol.m-2.s-1的情况下,其Pn达到很高水平,仍能维持基本的光合生理能力。表明车桑子在干热河谷的干旱季节对缺水胁迫和高光强有很强的适应能力。     

Virulence properties of Moritella viscosa extracellular products

Moritella viscosa is the causative agent of winter ulcer disease of marine fish. Knowledge of its pathogenicity is limited and there are no reports comparing the virulence properties of a collection of bacterial isolates. The in vivo and in vitro virulence of the extracellular products (ECP) of 22 M. viscosa isolates was screened. Two non-virulent Canadian isolates and a Norwegian isolate with reduced virulence produced non-lethal ECP. Correlation was obtained between cytotoxin and haemolysin production of M. viscosa. Isolates from salmon produced ECP with lower cytotoxic and haemolytic activities than ECP of isolates originating from other hosts. Correlation was not found between lethality of ECPs in salmon and cytotoxic or haemolytic activities. All isolates secreted esterases and a metallopeptidase (MvP1), degraded starch and produced siderophores. Variable levels of ECP protein concentration, different enzymatic activities and siderophore production could not explain differences in virulence. The results show that virulent M. viscosa isolates secrete a lethal toxic factor of unknown nature and that cytotoxin production may reflect host adaptation. Cell-culture models may not be optimal for determining the virulence of M. viscosa, as no association between cytotoxicity and bacterial virulence was obtained. Non-virulent strains may be useful in future research on M. viscosa virulence, as construction of mutants has not been successful.     

坡柳种子石油醚提取物对玉米象的生物活性

研究了坡柳种子石油醚提取物对玉米象的毒杀、熏蒸和种群抑制作用。结果表明,坡柳种子石油醚提取物在处理后7 d和14 d对玉米象成虫毒杀活性的LC50分别为1.6646 g/kg和1.1994 g/kg。处理24 h后熏蒸活性的LC50为3252.80mg/L。在浓度为2000 mg/kg时,对种群的抑制率达到68.04%。     

云南干热河谷4种植物抗旱机理的研究

通过干旱胁迫试验,对云南干热河谷4种植物的抗旱机理进行了研究。选用与植物抗旱性关系密切的8个生理生化测定指标:叶片相对含水量、相对电导率、MDA、SOD、POD、荧光、叶绿素含量、Pro,运用模糊数学中的隶属函数方法对云南干热河谷的车桑子、清香木两个原生植物和山毛豆、银合欢两个引种植物容器苗的抗旱性能进行了系统地综合评价。从而克服了单项生理生化指标的片面性,使评定结果较客观全面地反映此4种干热河谷植物的抗旱机理。     

干旱胁迫下3树种苗木叶片相对含水量、质膜相对透性和脯氨酸含量的变化

以金沙江干热河谷主要造林树种坡柳、银合欢和山毛豆的苗木为实验材料,通过盆栽苗自然干旱胁迫,同时以浇水处理为对照,探讨了干旱胁迫下3树种苗木叶片的相对含水量、质膜透性以及脯氨酸含量的变化情况。结果表明,干旱胁迫后,3树种苗木叶片的相对含水量、质膜相对透性以及脯氨酸含量都发生了变化,只是变化的幅度和进程不同。经三项生理指标的综合分析并结合3树种的自然表现,得出坡柳具有较强的抗旱能力,其次为银合欢,最后是山毛豆。     

Experimental infection of turbot, Scophthalmus maximus (L.), by Moritella viscosa, vaccination effort and vaccine-induced side-effects

Moritella viscosa is the causative agent of winter ulcers in farmed salmonids and Atlantic cod in countries around the North Atlantic. The bacterium has also been isolated from various marine fish species. Bacterial diseases have been a limiting factor in farming of turbot, but M. viscosa has not so far been isolated. In this study, turbot was shown to be sensitive to M. viscosa infection in experimental challenges. Pathological changes in infected turbot were comparable with those previously described for winter ulcers in salmon. A multivalent commercial salmon vaccine, containing M. viscosa as one of five antigens and a mineral oil adjuvant, did not protect turbot against challenge 13 weeks post-vaccination. Weight gain of vaccinated turbot compared with controls was not reduced 7 weeks post-vaccination. Vaccination did not induce a specific anti-M. viscosa response, while elevated anti-M. viscosa antibody levels were detected both in vaccinated and unvaccinated fish 5 weeks post-challenge. The vaccine did, however, induce an antibody response against Aeromonas salmonicida, another vaccine component. Minor intra-abdominal adhesions were detected in vaccinated fish and fish injected with a mineral oil adjuvant. The measurement of various innate humoral immune parameters did not reveal significant differences between vaccinated and control groups.     

车桑子和白刺花种子质量分级标准初步研究

车桑子(Dodonaea viscosa(L.)Jacq.)和白刺花(Sophora viciifolia Hance)是我省飞机播种造林的主要树种。由于在判定这两个树种种子质量时既无国家标准,又无地方标准作为依据,因此给种子质量评价和监督造成一定困难。本文通过对2001-2005年四川省林木种苗质量监督检测中心及凉山州林业种子种苗管理站车桑子和白刺花种子样品检测数据进行处理与分析,初步提出这两个树种种子质量分级标准的指标体系。     

A comparative study of susceptibility and induced pathology of cod, Gadus morhua (L.), and halibut, Hippoglossus hippoglossus (L.), following experimental infection with Moritella viscosa

In this study experimental challenges with Moritella viscosa, the causative agent of winter ulcers in salmonids, were performed on juvenile Atlantic cod and Atlantic halibut. The challenges involved both intramuscular (i.m.) and intraperitoneal (i.p.) injections and bath with a strain originally isolated from Atlantic salmon. Cod was found to be significantly more sensitive than halibut to the infection. Both fish species were found to be more sensitive to i.m. than i.p. challenges. Both challenges induced a systemic disease in cod and halibut, but only cod was infected with an experimental bath challenge. Pathognomonic signs were found to be comparable with those described in M. viscosa-infected salmon and turbot. The main distinguishing pathological sign was that the cod showed host response to M. viscosa infection resulting in granuloma formation in infected tissues, which is a known response of cod to a infection with another Gram-negative bacterium, Aeromonas salmonicida. Re-isolation of M. viscosa from kidneys of cod and halibut with clear disease signs was problematic and optimization of isolation measures is needed. The results of this study indicate that M. viscosa infection may be a risk factor in cod farming, but that halibut is more resistant.     

锰胁迫对黄花草种子萌发及幼苗生理生化特征的影响

为探明锰胁迫下黄花草的抗性生理适应机制,以该植物种子为试验材料,研究了不同浓度锰(0,1000,5000,10000,15000和20000 μmol·L^-1)胁迫对黄花草种子萌发、幼苗生长的影响及胁迫7、15、30 d生理生化特征的变化。结果表明:1)随着锰浓度的增加,黄花草种子的发芽势、发芽率、发芽指数和活力指数均呈下降趋势;幼苗芽长、根长、生物量和根冠比则先增加后下降,呈现出“低促高抑”现象;2)1000~5000 μmol·L^-1锰处理增加了黄花草幼苗叶片叶绿素a、叶绿素b、叶绿素a+b含量和叶绿素a/b值;当浓度继续增加且胁迫时间延长时,叶绿素含量和叶绿素a/b值降低;3)在胁迫第7天,黄花草叶片超氧化物歧化酶(SOD)活性随锰浓度增加逐渐下降,过氧化物酶(POD)和过氧化氢酶(CAT)活性随锰浓度增加呈上升趋势;在胁迫第30天,SOD和POD活性均显著下降,CAT活性无明显下降;4)黄花草幼苗叶片中脯氨酸、可溶性蛋白和可溶性糖含量在胁迫第7、15天随锰浓度增加而增加,在胁迫30 d后则均下降;5)丙二醛(MDA)含量随着锰浓度的增加和胁迫时间的延长而显著增加。研究结果表明,1000~5000 μmol·L^-1锰处理会促进黄花草幼苗的生长;该植物可以通过不同抗氧化酶差异化响应及渗透调节物质含量的提高,减轻高浓度锰胁迫所造成的损伤,提高对锰的耐性。     

Impact of co-infection with Lepeophtheirus salmonis and Moritella viscosa on inflammatory and immune responses of Atlantic salmon (Salmo salar)

This study was conducted to determine the effects of a co-infection with Moritella viscosa at different exposure levels of sea lice Lepeophtheirus salmonis in Atlantic salmon (Salmo salar). M. viscosa (1.14 × 10⁶ cfu/ml) was introduced to all experimental tanks at 10 days post-lice infection (dpLs). Mean lice counts decreased over time in both the medium lice co-infection (31.5 ± 19.0 at 7 dpLs; 16.9 ± 9.3 at 46 dpLs) and high lice co-infection (62.0 ± 10.8 at 7 dpLs; 37.6 ± 11.3 at 46 dpLs). There were significantly higher mortalities and more severe skin lesions in the high lice co-infected group compared to medium lice co-infected group or M. viscosa-only infection. Quantitative gene expression analysis detected a significant upregulation of genes in skin from the high lice co-infection group consistent with severe inflammation (il-8, mmp-9, hep, saa). Skin lesions retrieved throughout the study were positive for M. viscosa growth, but these were rarely located in regions associated with lice. These results suggest that while M. viscosa infection itself may induce skin lesion development in salmon, co-infection with high numbers of lice can enhance this impact and significantly reduce the ability of these lesions to resolve, resulting in increased mortality.