Comparative immunocytological study of prolactin and somatotropin cells in Alytes obstetricans (Laur.) tadpoles raised in groups or isolated]

In the anterior pituitary of Alytes obstetricans Tadpoles in premetamorphic stages, two cell types were localized by cytoimmunological techniques: orangeophilic cells secreting a prolactin-like hormone in the anterior and median region and erythrosinophilic cells secreting growth hormone in a more caudal situation. Both cells are more numerous and stimulated in grouped Tadpoles than in isolated ones.     

以决定为基础的软件开发:设计和维护

软件维护是由一系列活动组成的:对所需改变的理解、评价、分析、实现和检验等等。我们为软件维护提出了一种以决定为基础的开发方法.在这个方法中,根据各种软件实体所涉及的决定把这些实体联系在一起。用决定把问题与结论相连,给出开发、维护过程中考虑过的各种选择方案,并对特定的选择做出评价.一个决定,或者相关的一组决定,提供了与那个决定有关的软件系统的一个视图,并且可以让用户获取根据那个决定产生的原程序.这篇文章介绍以决定为基础的越级软件工程工具(D-HyperCase)的设计.D-HyperCase是以决定为基础的软件开发支撑系统的原型。由于我们正在使用以决定为基础的方法开发这个系统,所以,也介绍一下我们使用这种方法的体验.     

Beobachtungen zur Beschleunigung der Geschlechtsreife junger Mäuseweibchen durch die Gegenwart adulter Männchen und durch exogenes Oestrogen

Summary The influence of the presence of adult males on the acceleration of sexual maturation of female mice was examined under various experimental conditions and compared with the influence of exogenous oestrogen. The criteria of sexual maturation were not equally influenced. It is concluded that sexual maturation is a complex feature and that acceleration of single criteria does not signify sexual maturation.     

GABA regulates synaptic integration of newly generated neurons in the adult brain

Adult neurogenesis, the birth and integration of new neurons from adult neural stem cells, is a striking form of structural plasticity and highlights the regenerative capacity of the adult mammalian brain. Accumulating evidence suggests that neuronal activity regulates adult neurogenesis and that new neurons contribute to specific brain functions. The mechanism that regulates the integration of newly generated neurons into the pre-existing functional circuitry in the adult brain is unknown. Here we show that newborn granule cells in the dentate gyrus of the adult hippocampus are tonically activated by ambient GABA (gamma-aminobutyric acid) before being sequentially innervated by GABA- and glutamate-mediated synaptic inputs. GABA, the major inhibitory neurotransmitter in the adult brain, initially exerts an excitatory action on newborn neurons owing to their high cytoplasmic chloride ion content. Conversion of GABA-induced depolarization (excitation) into hyperpolarization (inhibition) in newborn neurons leads to marked defects in their synapse formation and dendritic development in vivo. Our study identifies an essential role for GABA in the synaptic integration of newly generated neurons in the adult brain, and suggests an unexpected mechanism for activity-dependent regulation of adult neurogenesis, in which newborn neurons may sense neuronal network activity through tonic and phasic GABA activation.     

Human chromosome 11 DNA sequence and analysis including novel gene identification

Chromosome 11, although average in size, is one of the most gene- and disease-rich chromosomes in the human genome. Initial gene annotation indicates an average gene density of 11.6 genes per megabase, including 1,524 protein-coding genes, some of which were identified using novel methods, and 765 pseudogenes. One-quarter of the protein-coding genes shows overlap with other genes. Of the 856 olfactory receptor genes in the human genome, more than 40% are located in 28 single- and multi-gene clusters along this chromosome. Out of the 171 disorders currently attributed to the chromosome, 86 remain for which the underlying molecular basis is not yet known, including several mendelian traits, cancer and susceptibility loci. The high-quality data presented here--nearly 134.5 million base pairs representing 99.8% coverage of the euchromatic sequence--provide scientists with a solid foundation for understanding the genetic basis of these disorders and other biological phenomena.