真核生物异染色质生化组成及超微结构研究进展

概述了异染色质生化组成及其在超微结构方面的研究进展，着重介绍了着丝粒的异染色质超微结构研究。     

广东5种家鼠染色体结构异染色质分布特征研究

本文采用骨髓细胞直接制片法和ＢＳＧ技术研究了广东５种家鼠（褐家鼠、黄胸鼠、黄毛鼠、屋顶鼠和社鼠）的Ｃ－带分布特征，结果表明：该地区５种家鼠Ｃ－带带型具有种间的差异，结构异染色质分布特点，由黄胸鼠到黄毛鼠、褐家鼠，施氏屋顶鼠、社鼠、依次呈递减的趋势，并结合有关研究，对不同地区的同一物种，其结构异染色质的多态性进行讨论。     

The largest known chromosome number for a mammal,in a South American desert rodent

Summary Tympanoctomys barrerae, a desert specialist member of the family Octodontidae, until now thought to be conservative, and ancestral to South American hystricognath rodents, presents the highest diploid chromosome number (2n=102) known in a mammal. Unexpectedly, its karyotype was found to be composed mainly of metacentric to sub-metacentric chromosomes. Mechanisms by which such a karyotype may have been derived are discussed.     

C-band differentiation between the chromosomes of two subspecies of the chironomid midgeChironomus thummi

Summary The metaphase chromosomes ofChironomus th. thummi contain approximately 17% more pericentric C-band heterochromatin than the chromosomes ofChironomus th. piger with 11% heterochromatin. InCh. th. thummi, the proportion of heterochromatin appeared to be much larger in metaphase chromosomes than in polytene chromosomes. This discrepancy is interpreted as being due to the specific chromosome organization and not as the result of an underreplication of heterochromatin during polytenization.     

C-band variability in some Lacertidae (Sauria,Reptilia)

Summary The chromosome C-banding pattern has been studied in four lacertid species possessing the same karyotype. The results obtained show a remarkable interspecific variability both in the amount and distribution of C-banded heterochromatin. This leads us to the speculation that alleged conservativeness in their karyology is probably due to inadequate resolution by the conventional cytological techniques. Moreover, it has been hypothesized that these variations of the C-bands play an important role in the evolution of this saurian family.This research was supported by a grant from the Ministero Pubblica Istruzione.     

南黄大麦染色体C带分析

采用改进的 HBSG—C 带程序,对南黄大麦染色体成功地进行了分带.南黄大麦的带型公式为2n=2x=14=2CIT+2CIT+2CIT+2CIT+2CI_+T+2CI_+TN+2CITN.一个染色体组所显带纹数量高达32条,而且较分散,可作为分析染色体结构变异的工具.本文还对南黄大麦染色体上的异染色质分布情况进行了分析.     

A comparative analysis of the cell biology of senescence and aging

Various intracellular organelles, such as lysosomes, mitochondria, nuclei, and cytoskeletons, change during replicative senescence, but the utility of these changes as general markers of senescence and their significance with respect to functional alterations have not been comprehensively reviewed. Furthermore, the relevance of these alterations to cellular and functional changes in aging animals is poorly understood. In this paper, we review the studies that report these senescence-associated changes in various aging cells and their underlying mechanisms. Changes associated with lysosomes and mitochondria are found not only in cells undergoing replicative or induced senescence but also in postmitotic cells isolated from aged organisms. In contrast, other changes occur mainly in cells undergoing in vitro senescence. Comparison of age-related changes and their underlying mechanisms in in vitro senescent cells and aged postmitotic cells would reveal the relevance of replicative senescence to the physiological processes occurring in postmitotic cells as individuals age.