A review of cyanobacterial odorous and bioactive metabolites: Impacts and management alternatives in aquaculture

Increased demand has pushed extensive aquaculture towards intensively operated production systems, commonly resulting in eutrophic conditions and cyanobacterial blooms. This review summarizes those cyanobacterial secondary metabolites that can cause undesirable tastes and odors (odorous metabolites) or are biochemically active (bioactive metabolites) in marine and freshwater, extensive and intensive aquaculture systems. For the scope of this paper, biochemically active metabolites include (1) toxins that can cause mortality in aquaculture organisms or have the potential to harm consumers via accumulation in the product (hepatotoxins, cytotoxins, neurotoxins, dermatoxins, and brine shrimp/molluskal toxins), (2) metabolites that may degrade the nutritional status of aquaculture species (inhibitors of proteases and grazer deterrents) or (3) metabolites that have the potential to negatively affect the general health of aquaculture species or aquaculture laborers (dermatoxins, irritant toxins, hepatotoxins, cytotoxins). Suggestions are made as to future management practices in intensive and extensive aquaculture and the potential exposure pathways to aquaculture species and human consumers are identified.     

Increase of in vitro regeneration in Malus domestica by the application of phosphatase inhibitors

The effect of the phosphatase inhibitors sodium fluoride and sodium orthovanadaate on adventitious shoot regeneration from primary leaf explants was tested in eight genotypes of apple Malus domestica Borkh. Ten different concentrations between 0.5 and 100μM of each substance were added to a modified Murashige and Skoog regeneration medium containing 0.9 μM TDZ and 0.5 μM IBA. In general, all the con-centrations tested were able to promote shoot formation, although distinct maxima could be observed depending upon the genotype and the inhibitor. Shoot yield was influenced mostly by the genotype and by the concentration of the inhibitor, as well as the interaction between these two factors. In six of the eight genotypes the total number of regenerated shoots increased significantly compared with the control. This was achieved by an increase of the number of regenerating explants as well as the number of shoots per regenerating explant Comparing these results with those of former publications, application of the two phosphatase inhibitors resulted in an improved regeneration response in the corresponding genotypes. This method may also contribute to the understanding of in vitro regeneration in plants.     

缺失SBTi—A2大豆杂交后代品系籽粒化学成分分析

对一个杂交组合后代１０个稳定缺失胰蛋白酶抑制剂（ＳＢＴｉ－Ａ２）品系及其亲本籽粒化学成分组成进行的分析比较表明，大豆籽粒中缺失ＳＢＴｉ－Ａ２对其蛋白质含量及天门冬氨酸、甘氨酸和丙氨酸含量有一定影响，表现为缺失ＳＢＴｉ－Ａ２品系显著低于高亲和双亲平均值；而对其他氨基酸和脂肪含量及脂肪酸组成基本没有显著的影响。     

Alpha-amylase/subtilisin Inhibitor Levels in Australian Barleys

An enzyme-linked immunosorbent assay (ELISA) was used to determine the bifunctional alpha-amylase/subtilisin inhibitor (BASI) content of barley grain from 11 cultivars grown in six diverse locations in Australia. The inhibitor ranged from 119 to 254 μg/g in 57 barley samples. Genotype had a significant (P<0·05) effect on BASI content but there was no effect due to environment. Total protein varied independently of BASI and was influenced by environment and genotype. BASI content was higher (P<0·05) in malting barley than in feed barley and was correlated positively (r=0·29;P<0·05) with alpha-amylase activity in corresponding malts. The ELISA used monoclonal and polyclonal antibodies raised against purified BASI. In immunoblot analysis the monoclonal antibody showed high specificity for the inhibitor in barley and also detected the inhibitor in wheat. Low levels of inhibitor (mean 3·2 μg/g) were found in 12 Australian wheat cultivars using the ELISA developed for barley. The assay had a linear working range of 5–50 ng/mL with a detection limit of 2 ng/mL. Reproducibility between assays was good (CV=4·9%) but mean recoveries were high, ranging from 116–129% when purified inhibitor was added to barley extracts. The ELISA may have useful applications in brewing research and barley breeding programmes.     

不同热处理对黑豆干物质消化率,蛋白质消化率的影响

为了研究热处理的温度和时间对黑豆干物质消化率(DMD)、蛋白质消化率(PD)及脲酶活性的影响规律,对经过110℃和121℃下分别处理3,9和15min的饲用黑豆进行了离体干物质消化率和离体蛋白质消化率及脲酶活性的测定。结果表明:在121℃处理15min的样本干物质消化率和蛋白质消化率最高,分别为75.13%,90.91%,脲酶活性最低,为0.04mg/min·g。作者认为:在本研究范围内,湿热处理最适宜的温度是121℃,时间是15min。     

油菜(B.juncea L.)温敏核不育的温度敏感基因分析

温敏核不育是雄性育性可受温度调节的一种不育类型.1999年云南省农科院从油菜(Brassica juncea L.)核不育材料"05S"中同时选育得到一个温敏核不育系"K121S"和一个不具温敏性的核不育两型系"116A".遗传试验表明,它们的雄性不育基因等位,不育性由核内2对隐性重叠基因控制,对温度敏感与否与另一对同不育基因互作的抑制基因有关,携带隐性纯合抑制基因的不育系(K121S),低温条件下其不育基因的作用被抑制而表现可育,高温条件下抑制基因作用失活,不育系仍表现雄性不育;携带显性纯合抑制基因的不育系(116A)其育性则不受温度影响.因此,在油菜温敏核不育"K121S"中,隐性抑制基因作用的温敏性导致了不育性的温敏性.     

烘烤过程多酚氧化酶抑制剂对烤烟多酚的影响

 选用4种多酚氧化酶抑制剂处理备烤烟叶,与对照进行烘烤比较试验。通过对烤后烤烟样品总酚、绿原酸、芸香苷含量及烘烤前鲜烟匀浆中多酚氧化酶活性的检测。比较结果显示：常规烘烤条件下4种抑制剂对烤烟多酚含量无明显影响;在不当的烘烤条件下,4种处理样品的多酚含量明显高于对照,其中对烤烟多酚降解抑制作用最强的是NaDiCa,聚乙烯吡咯烷酮相对弱些但无异味,它们可能是防止不当烘烤导致烟叶褐变的有效抑制剂。鲜活烤烟匀浆中4种抑制剂对多酚氧化酶活性抑制作用由强到弱依次为NaDiCa,聚乙烯吡咯烷酮,EDTA和硫脲。匀浆酶活性检测结果与整叶烘烤处理后烤烟样品总酚含量高低顺序不完全一致,可能是不同抑制剂在烟叶组织中渗透性不一致引起,值得进一步研究。     

小分子植物病毒抑制物质研究进展

论述了小分子病毒抑制物的结构及对病毒的抑制机理 ,讨论了植物病毒抑制剂研究中存在的问题及研究前景     

大白菜开花基因 LFY的克隆及dsRNA抑制载体的构建

以中国大白菜花蕾为材料，通过RT-PCR方法，参照GeneBank公布的序列克隆了Leafy(简称LFY)基因片段，测序分析结果表明，该基因与国外已经报道的序列具有94％的同源性。将此序列以相反方向插入到植物表达载体pROK2 35S启动子之间，并在2反向重复片段之间插入小麦乙酰辅酶A羧化酶的第20内舍子，从而构建了dsRNA抑制双元载体，该载体的构建为通过农杆菌介导转化大白菜进而解决早春扣反季栽培大白菜的先期抽薹问题创造了条件。     

外源基因在不结球白菜转基因植株后代中的表达

应用农杆菌介导法将含有豇豆胰蛋白酶抑制剂基因和新霉素磷酸转移酶基因的重组质粒导入不结球白菜地方品种———“中脚黑叶”和“矮脚黑叶”中 ,获得抗虫转基因植株。卡那霉素抗性和抗虫性在转基因植株自交后代T1代植株中发生分离 ;在T2 代中出现 3种不同类型的株系 :抗性纯合、杂合型和敏感性纯合株系。卡那霉素抗性和抗虫性在转基因植株自交后代中的表现基本符合孟德尔显性单基因的分离规律。从T2 、T3 、T4代中选择出抗虫性纯合株系 ,并获得一批对 1～ 2龄鳞翅目小菜蛾、斜纹夜蛾幼虫的校正死亡率达 6 0 %左右的单株