ISSN:0265-9247    

DOI:10.1002/bies.950050102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractDimorphism in the yeastCandida albicansprovides an unusually simple model system for investigating the mechanisms which regulate cellular differentiation, or cell divergence. Under the regime of pH‐regulated dimorphism, it has been demonstrated that the programs of protein synthesis accompanying bud and hypha formation are strikingly similar. Instead of dramatic differences in the repertoire of gene products possessed by bud‐ and hypha‐forming cells, subtle temporal, spatial and quantitative differences in the same architectural events appear to be basic to the genesis of alternative phenotypes. This emerging story of phenotypic regulation does not exclude differential gene expression, but rather de‐emphasizes its role and underscores other mechanisms which are not generally con

ISSN:0265-9247    

DOI:10.1002/bies.950050103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractIon channels play key roles in the generation and propagation of nerve impulses by mediating ionic fluxes across excitable membranes. Elucidation of the structure and function of these proteins is a major goal in understanding the molecular mechanisms of membrane excitability. Much work has focused on sodium channels, whose activity is of primary importance in producing nerve impulses. Despite the recent cloning and sequencing of a sodium channel structural gene, many unanswered questions remain. To address some of these question genetically,Drosophilamutants with altered sodium channels are being isolated and subjected to multidisciplinary analyses. Ultimately, these can provide novel approaches for understanding the function and regulation of sodium channels at a molecular level.

ISSN:0265-9247    

DOI:10.1002/bies.950050104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractIt now appears that the molecular events associated with the mitogenic action of growth factors are also the events perturbed in neoplastic lesions. This review outlines the relevance of our recent progress in the biochemistry of growth factors and their receptors to the induction and maintenance of the neoplastic state.

ISSN:0265-9247    

DOI:10.1002/bies.950050105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractCell lines and cell samples from patients provide opportunities for studying the mechanisms of leukemic cellular differentiation and proliferation. Phorbol esters and 1,25 dihydroxy vitamin D3can induce differentiation of myeloid leukemic cells to macrophages. Differentiation to granulocytes can be induced by several different compounds. Myeloid differentiation is associated closely with the alteration in expression of several oncogenes. These regulatory events may be associated with the extent of methylation, unfolding or association of chromatin to the nuclear matrix. Oncogene amplification, mutation, or deletion can occur with malignant transformation. Future studies point to the development of specific pharmacological agents which can modify the neoplastic transformation.

ISSN:0265-9247    

DOI:10.1002/bies.950050106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractPyridoxal 5′‐phosphate, the vitamin B6derivative, acts as the coenzyme of many enzymes involved in amino acid metabolism. Exceptionally, this compound was found covalently bound to glycogen phosphorylase, the key enzyme in the regulation of glycogen metabolism. Although it is essential for the function of phosphorylase, its direct role has remained an enigma. We have recently found that the glucose moiety of pyridoxal (5′)diphospho (1)‐α‐D‐glucose, a conjugate of pyridoxal5′‐phosphate and glucose1‐phosphate through a pyrophosphate linkage, is transferred to the nonreducing end of glycogen, forming a newα‐1,4‐glucosidic linkage. This finding emphasizes the importance of the direct phosphate‐phosphate interaction between the coenzyme and the substrate in the phosphorylase catalytic reaction. We have proposed a catalytic mechanism for phosphorylase in which the phosphate group of pyridoxal5′‐phosphate acts as an electrophile to the phosphate group of glucose1‐phosphate. This appears to represent the first instance of the direct involvement of a phosphat

ISSN:0265-9247    

DOI:10.1002/bies.950050107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractMammalian neural cells contain at least two forms of brain spectrin: brain spectrin (240/235) which is located primarily in the axons and presynaptic terminals of neurons, and brain spectrin (240/235E) which is found in the cell bodies, dendrites and postsynaptic terminals of neurones. Brain spectrin (240/235E) is also found in certain glial cell types. Antibodies against red blood cell spectrin detect only brain spectrin (240/235E), while antibodies against brain spectrin isolated from axonal and synaptic membranes detect brain spectrin (240/235). Previous apparent discrepancies in the literature concerning brain spectrin localization at the light microscope level were undoubtedly due to different laboratories detecting distinct brain spectrin subtypes, based on the particular antibody being utilized for immunohistochemistry. In this review we (1) discuss the data supporting the presence of at least two distinct subtypes of mammalian brain spectrin, (2) explain how these results reconcile previous discrepancies concerning the localization of spectrin within neural cells, and (3) suggest the future implications of these findings.

ISSN:0265-9247    

DOI:10.1002/bies.950050108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950050109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

ISSN:0265-9247    

DOI:10.1002/bies.950050110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY

摘要:

AbstractThe progressive unraveling over the past fifteen years of the structure and function of the human mitochondrial genome, taken as a prototype of all vertebrate mitochondrial genomes, has been marked by a series of startling discoveries. The history of these developments is one in which prediction often turned out to be wrong, and in which solidly established dogmas were violated. The unique features of this genome have forced a revision of our ideas about the universality of the genetic code and of the decoding mechanism, the minimal structural requirements for rRNA, tRNA and mRNA function and the mode and control of gene expression.

ISSN:0265-9247    

DOI:10.1002/bies.950050111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1986

数据来源: WILEY