Characterization of the DNA nucleotide sequences in the genome of red sea bream iridoviruses isolated in Korea

The nucleotide sequences of DNA fragments amplified by polymerase chain reaction (PCR) from four different genomic regions of nine red sea bream iridoviruses (RSIVs) isolated from different species of fish, different areas and in different years in Korea were compared with the reported reference sequences. One isolate, RSIV Namhae, showed 100% homology to the reference sequences, while the other eight isolates, which appeared to contain identical nucleotide sequences, showed 96.6–98.9% homology with reference sequences depending upon the target regions of PCR gene amplification. However, differences in nucleotide sequences were not apparent between the RSIVs isolated in different locations, in different years or in different host species. We also cloned and sequenced the 3′ end flanking region (K1) of the DNA polymerase (DPOL) gene using the cassette ligation-mediated PCR method. This sequence was 4436-bp long and possessed two open reading frames (ORF-1 and ORF-2) oriented in opposite directions. The putative proteins encoded by these two ORFs could not be characterized by comparison with the proteins of other species in the data banks. The presence of the ribonucleotide reductase small subunit (RNRS) gene at the 3′ end of the K1 region allowed us to determine that these two genes, RNRS and DPOL, are separated 5508 bp and oriented in the same direction in the genome of RSIV. Moreover, it is of interest that a PstI-restriction fragment, of which the sequence but not the location within the RSIV genome had previously been reported, is located at nucleotide positions from 1096 to 2054, extending from within the ORF-1 region, spanning the intervening sequence between ORF-1 and ORF-2, and extending into the ORF-2 region. Various repeating sequences up to 86 bp were present at the 3′ ends of ORFs, especially within the nucleotide sequences at the 3′ terminus of ORF-2. No similarities were detected when the DNA sequences of the K1 region were compared to the DNA sequences of a repetitive element in the genome of other iridoviruses.     

Balenine,imidazole dipeptide,induces activation of superoxide dismutase in myotubes

Balenine is one of the endogenous imidazole dipeptides. It is composed of beta-alanine and 3-methyl-l-histidine, which exist mainly in the muscles and the brain. The exact biological properties of balenine are still not well known, although the antioxidant activity of carnosine, another imidazole dipeptide, is known. In this study we investigated whether balenine exhibits antioxidant activity. It was found to decrease the superoxide anion (O₂⁻) and increased hydrogen peroxide (H₂O₂) generation. We found that SOD activity increased in balenine-treated C2C12 myotubes, although balenine did not increase expression of SOD mRNA. On the other hand, there were no changes in other antioxidant enzymes, CAT and GPX activity, and mRNA levels. In an in vitro assay, the direct activation of SOD treated by balenine was significantly higher than with carnosine treatment. Moreover, balenine constituent amino acids did not have the ability to activate SOD. Our results suggest that balenine contributes to antioxidant effects through activation of SOD.

     

二十二碳六烯酸和二十碳五烯酸的代谢研究

二十二碳六烯酸(Decosahexaenoic acid,DHA)和二十碳五烯酸(Eicosapentaenoic acid,EPA)是人体不能自行合成、只能从食物中摄取的必需高度不饱和脂肪酸(HUFAs)。自Dyerberg等[1]指出EPA有益于人类健康以来,EPA和DHA受到广泛的关注,成为研究热点。对EPA和DHA的功能进行的许多研究表明,适宜的EPA、DHA绝对量和比例在人、动物的正常繁殖、生长、发育中发挥着非常重要的生理作用[2-7];而不同动物、个体和时期对EPA和DHA的需求量及适宜比例均不相同。由于以往研究主要集中于EPA和DHA生理作用方面,而且主要以哺乳动物为研究对…     

漂白粉蓄积对日本蟳4种组织超微结构的影响

根据急性毒性试验确定了漂白粉对日本蟳的安全质量浓度为0．6mg／L，采用透射电镜技术研究了该质量浓度下漂白粉蓄积对日本蟳4种组织细胞(肌肉、鳃、肝胰脏和心脏)超微结构的影响。试验结果表明：漂白粉主要损伤日本蟳的鳃和肝胰脏，其次是心脏，肌肉基本无损害。鳃细胞的损害表现为鳃丝水肿，细胞器溶解，角质层变薄，线粒体、内质网的肿胀、解体；肝胰脏细胞的主要损害特征为肝管微绒毛减少、线粒体水肿解体、内质网扩张、细胞核空泡化、核膜水肿、脂肪滴增加；心脏细胞的毒理变化为线粒体内嵴肿胀、瓦解，肌原纤维不规则，内质网溶解。安全质量浓度的漂白粉经16d蓄积后，虽没有导致日本蟳死亡，但已对其体内的鳃、肝胰脏、心脏等组织细胞的超微结构产生了不同程度的影响。     

利用速冻蓝莓酿制蓝莓酒的技术研究

以速冻蓝莓为原料,通过对冻藏和常温蓝莓汁发酵进行比较,研究菌种及接种量、发酵温度、澄清方法,确定最佳工艺。结果表明：经冻藏处理的蓝莓与新鲜果实发酵的果酒品质没有太大区别。采用果酒酵母3#,接种量3％,主发酵温度控制在10-15℃,发酵时间12d,硅藻土用量为2．5％时,能生产出优质的蓝莓酒。     

山东潍坊市园林植物病虫害可持续控制研究

对潍坊园林植物主要病虫害进行调查,分析其发生特点,并提出相应对策:强调以生态学为基础,以生物防治为主导,综合采用植物检疫、栽培管理、化学防治等方法,达到对病虫害可持续控制的目的。     

黄瓜苗期生长及育苗方式的研究

为了探究黄瓜苗期生长发育规律和育苗方式,以华南型黄瓜‘沪杂7号’和荷短型黄瓜‘春秋王2号’为试材,用卡尺对植株高度、茎粗度、子叶大小、叶片大小进行测量,用天平称量地上部、根鲜质量,电子秤称量产量,利用LI-6400型光合仪对气体交换参数净光合速率(Pn)、气孔导度(Gs)、胞间CO2浓度(Ci)与蒸腾速率(Tr)进行测量。结果表明,黄瓜植株高度、茎粗度增长均似线形,育苗后期生长速度更快,叶片长度、宽度增长速度前期较快,后期略慢;定植前大苗光合作用明显好于小苗,地上部、根鲜质量均显著高于小苗;华南型、荷短型黄瓜大苗定植,较小苗定植采收期均提前10 d以上,同时总产量明显增加。大苗定植对黄瓜提前上市及增加收入有明显效果。     

不同饵料及其组合对黑鲍幼鲍生长及存活的影响

试验研究人工配合饲料、细基江蓠繁枝变种(Gracilaria tenuistipitata)(下称江蓠)、江蓠 裂片石莼(Ulva faxciata)、江蓠 肠浒苔(Enteromorpha intesinalis)、江蓠 裂片石莼 肠浒苔共5种饵料搭配方式对黑鲍幼鲍生长和存活的影响。试验进行35d,结果表明:(1)不同试验组之间的幼鲍的存活没有显著影响(P>0.05)。(2)不同试验处理对幼鲍的生长有显著影响(P<0.05)。江蓠 浒苔组、人工配合饲料组的黑鲍的特定生长率都显著大于其它饵料组(P<0.05);饲喂混合海藻的黑鲍的特定生长率显著大于单一海藻组(P<0.05)。壳长增长率、湿重增重率和干重增重率亦呈相似趋势。(3)幼鲍对不同饵料组合的转化效率存在显著差异(P<0.05)。试验结果表明,在水温较高时用江蓠、石莼和浒苔组成的混合饵料代替人工配合饲料饲养幼鲍,同样可以达到高的生长率。     

超声波在水产养殖中的应用

超声波具有机械传质、加热和空化作用。高强度的超声会破碎生物的细胞,降低酶活性等;合适的低强度超声波可以促进鱼卵孵化,提高鱼类的生长速度,去除有害藻类,并能增强鱼类的免疫功能,有利于鱼病防治。     

海南省琼中县橡胶园土壤磷素空间变异特征及磷肥分区管理分析

运用地统计学和GIS相结合对琼中县橡胶园土壤磷素营养进行了空间变异特征及分区管理研究。结果表明,琼中县胶园各土层土壤全磷和有效磷含量的最大相关距离是17.23~52.09 km,全磷含量以大块状变异为主,有效磷含量各等级的分布为大、小块状交叉分布;琼中县橡胶园0~20 cm土层、20~40 cm土层全磷含量处于第五等级的极低水平的比例分别为91.22%和82.8%,0~20 cm土层有效磷含量多数处于中等偏上水平,而20~40 cm土层有效磷含量处于第5等级及以下的极低水平的比例为60.6%;应用空间叠加方法,进行了橡胶园土壤磷素管理分区,琼中县胶园可分为11个管理分区,在胶园施肥管理中应根据不同管理分区的特点采取不同的磷素营养管理措施。