关于林边新藏羊和边新藏羊产毛性状和体性状的比较

用林肯羊与边新藏羊(边区来斯特、新疆细毛羊和藏羊的杂交后代)进行级进杂交,其后代(林边新藏羊)的毛丛长度、细度、剪毛量、初生重、断奶重等育种指标均优于边新藏羊,而且其在育成时期的体重与边新藏羊接近.     

Expression of the mutant gene for L-gulono-γ-lactone oxidase in scurvy-prone rats

A mutant strain of Wistar rats with L-gulono--lactone oxidase deficiency has recently been established. To investigate this deficiency by DNA and RNA blot hybridization analyses, a fragment of a previously cloned cDNA encoding rat L-gulono--lactone oxidase was used as a probe. When genomic DNA of the mutant rat was digested with several restriction enzymes, the probe hybridized to fragments of the same sizes as those produced from DNA of normal rats. Poly(A)⁺RNA from the liver of the mutant rat was found to contain an L-gulono--lactone oxidase-specific mRNA of a normal size at a comparable level to that of normal rats. An in vitro translation experiment revealed that the mRNA programmed the synthesis of an enzyme protein which had the same molecular weight as that of the translational product of the normal mRNA, although the amount synthesized was markedly reduced as compared with that synthesized with the normal mRNA. In accordance with this observation, a very low but definite degree of L-gulono--lactone oxidase activity was detected in the microsomes of the mutant rat by a newly developed, highly sensitive method.Acknowledgments. The authors thank Dr Susumu Makino, Shionogi Research Laboratories, Shionogi & Co., Ltd, Japan, for his kind donation of normal (ODS- +/+) and ODS (ODS-od/od) rats. This work was supported in part by Grant-in-Aid (59570103) for Scientific Research from the Ministry of Education, Science and Culture of Japan.     

生物素标记核酸探针杂交检测灵敏度的比较研究

用Biotin-11-dUTP进行缺口翻译缺备生物素标记的人β-珠蛋白基因探针并用该探针进行了斑点杂交，硝酸纤维素膜印迹杂交 及琼脂糖凝胶直接染交方法学比较，结果表明：经ABAP法显色后，上述三种杂交法中，DNA最低可检测量依次为5，10，50pg，以斑点杂交法最灵敏。     

由分子的“不饱和度”判断中心原子的杂化类型

提出了由分子的＂不饱和度＂判断中心原子轨道杂化方式的方法、应用及规律。     

绽放在加拿大英语文坛的《玉牡丹》——论崔维新获奖小说《玉牡丹》、加拿大华裔文本和杂糅

加拿大著名华裔作家崔维新数获大奖的英语小说《玉牡丹》,描述了华人金山梦如何破灭的过程。加拿大华裔文本通过杂糅化来解决身份问题的历史性努力值得赞赏。     

Heterospecific mating between distantly related species of stink bugs and its evolutionary implications

The copulatory process in animals is preceded by a series of integrated communication processes which are often under selection to guarantee species-specific courtship and copula. However, individuals of species supposedly in reproductive isolation frequently copulate in nature, which has sparked the attention of evolutionary biologists for decades. While studies on this topic have strongly focused on recently diverged species or populations, few instances of heterospecific copula between distantly related species are known. Here we report an intriguing case of interspecific copula between two distantly related species of stink bugs in nature. We replicated this observation in laboratory conditions and revealed an asymmetric relation: males of Chinavia obstinata copulated with females of C. erythrocnemis but the reverse combination did not occur. We propose a series of hypotheses to explain our observations in the light of the current knowledge on mate recognition and reproductive isolation in stink bugs, considering the potential pre- and postcopulatory barriers involved. Once these two species have probably evolved in allopatry and contacted secondarily, the absence of directional selection against mating signals differentiation is a probable process. We argue that similarities in genital shape and size, most likely a result of convergent evolution, may have played a fundamental role in guaranteeing that these species achieved proper coupling.     

In situ localization of ACTH receptor-like mRNA in molluscan and human immunocytes

Adrenocorticotropin hormone (ACTH) receptor-like messenger RNA was localized in molluscan hemocytes and human peripheral blood mononuclear cells by in situ hybridization using a digoxigenin-labelled bovine complementary DNA probe. These findings suggest that the ACTH receptor gene has been highly conserved during evolution. Moreover, these data represent further support for a relationship between the immune and neuroendocrine systems in invertebrates, as documented in our previous studies [1]. Received 25 September 1997; received after revision 12 November 1997; accepted 12 November 1997