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Abstract

The 6′-carboxylic acid derivative of neplanocin A 3 was synthesized from NPA, and was converted to the corresponding methyl ester 4 and amides 5 and 6. These were evaluated for their anti-RNA-virus activities. Of the derivatives synthesized, only 5 was active against RNA viruses within the concentration range of 0.14-4.88 μg/mL. Compounds 3 and 5 showed a potent inhibitory effect on S-adenosylhomocysteine (AdoHcy) hydrolase from rabbit erythrocytes. Although a close correlation between the inhibitory effect of adenosine analogues on AdoHcy hydrolase and their antiviral potency has been demonstrated, 3 did not show any anti-RNA-virus activities.

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Morphological differences in body shape between females of different reproductive conditions (in terms of insemination and ovarian development) were examined in two species of the Neotropical polistine genus Parachartergus: P. smithii and P. fraternus. The present study shows, for the first time, that non‐size‐based morphological divergence between queens and workers occurs in Parachartergus, an epiponine genus once believed to have little or no morphological caste differences. In the P. smithii colony examined, queens were significantly larger than workers in five of the eight body parts measured (head width, eye width, genal width, mesosomal length, wing length, first metasomal tergum width, and width and length of the second tergum), but the mean values of wing length and first and second tergum widths were not significantly different between them. The queen : worker size ratios tended to be greater anteriorly and smaller posteriorly, although the size ratio was greatest in second tergum length. Analysis of covariance (ancova ) with mesosomal length as covariate showed that queens had proportionally wider heads and narrower first terga than did workers. In the P. fraternus colony, size differences between queens and workers were not significant, and there was little or no difference in shape, but queens had significantly proportionally wider first terga than did workers.  相似文献   
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1. A type of arms race that includes predation, counterattacks and cross‐counterattacks occurs between the phytophagous mite Stigmaeopsis nanjingensis (Ma et Yuan), which lives in self‐woven nests and exhibits cooperative sociality, and its specialised phytoseiid mite predator, Typhlodromus bambusae Ehara. 2. First, the efficiency of the S. nanjingensis (prey) counterattacking T. bambusae (predator) was observed. The prey females frequently locked the immature predators out of their nests using silk web, and the predators subsequently died of starvation. Furthermore, the prey males often killed immature T. bambusae mites after they invaded the nests. 3. This reversal of roles in the predator–prey system was then re‐reversed (returned to a normal state) by the behaviour of T. bambusae females. Immature predators could maintain their predacious natures due to the presence of attending adult females, which are able to cope with the prey counterattack behaviours.  相似文献   
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本文报告小鼠GDP岩藻糖:β半乳糖苷α1,2-岩藻糖基转移酶(α1,2-fucosyltansferase,α1,2-FT)基因的克隆,并进行功能鉴定。利用RT—PCR方法克隆小鼠α1,2-岩藻糖基转移酶基因编码区MFUT-II,测序后将其插入表达载体pcDNA3.1的多克隆位点,构建表达载体pcDNA3.1-MFUT-II;采用磷酸钙法将其转染于COS-7细胞进行表达,通过对底物特异性比较研究酶的性质;应用Northern印迹杂交法研究基因在小鼠组织中的表达情况;应用Southern印迹杂交法分析基因存在状态。结果证实MFUT-II为小鼠α1,2-岩藻糖基转移酶基因家族的新成员。含有一个完整的开放读码框。可编码347个氨基酸。其估计分子质量为39kDa,和小鼠日及Sec1基因具有序列同源性。分别与人类Se基因(79.O%)、大鼠Ratrrs(89%)基因、兔Rabbit FT-III基因(77%)具有较高的序列同源性。用MFUT-II基因转染的COS-7细胞具有α1,2-FT活性。MFUT-II可在多种组织中产生3.5kb大小的mRNA转录产物。基因Southern印迹杂交分析结果显示:基因MFUT-II仅为一个拷贝。这些结果证明MFUT-II为小鼠的Se基因。  相似文献   
9.
Of the 22 species of Ropalidia occurring in Australia, only R. plebeiana is distributed in temperate areas. This wasp is abundant in the south‐eastern coastal regions of Australia, where it forms huge nest aggregations. Based on our observations in late autumn and early spring, as well as information in the literature, we outline the colony cycle of R. plebeiana in the south‐eastern coastal area of New South Wales. The nesting period lasts for approximately 9.5 months, which is unusually long for temperate polistine wasps. Most foundresses seem to return to their natal nests in early spring (mid‐August to early September) to start their own colonies by reusing pre‐existing nest combs, and the pre‐emergence stage (before the emergence of the first adult brood) lasts for approximately 3.5 months. Reproductives (gynes and males) start to emerge as adults in early March, and the reproductive‐producing period lasts until the end of May. Both the pre‐emergence stage and the reproductive‐producing period are much longer than in other temperate polistine wasps, which is discussed in terms of fluctuating temperature conditions in the area and the formation of nest aggregations, a peculiar habit for temperate populations of R. plebeiana.  相似文献   
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Floret elongation and levels of precarthamin were investigatedin freshly collected flowers of Carthamus tinctorius. Accumulationof precarthamin was found to be induced at the early stagesof floret elongation. [U-14C]Acetate and [U-14C]phenylalaninewere incorporated into precarthamin in the detached floretsfrom the flower bud. The results suggest that precarthamin issynthesized via the acetate-shikimate pathway. Carthamus tinctorius L, floret elongation, pigment synthesis, precarthamin  相似文献   
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