摘要:

Sigmund Freud, the acclaimed founder of psychoanalysis, invested nine years of his early scientific effort investigating animal histology, cell biology and basic neuroscience prior to concentrating on human nervous and mental disorders. Through his histological studies Freud provided coherent evidence suggesting that the protoplasm consists of a contractile fibrillary network, the present‐day cytoskeleton; he was one of the original founders of the fibrillary theory on the structure of the protoplasm. Concerning the biology of the cell nucleus, Freud appears to have been the first author who documented movements of nucleoli in nerve cells, a phenomenon presently referred to as nuclear rotation. In certain instances, Freud's observations antedate later views by more than half a century and are important to our current understanding of cell structure and basic processes of intracellular motilit

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00576.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Cell nuclei may contain significant quantities of the metals Fe, Ni, Cu, Zn, since they are present in the nucleo‐enzymes and/or nucleic acids. These metals have been detected by X‐ray microanalysis in situ in dinoflagellates (Kearns et al). Aluminum was only detected in cell nuclei in cases of natural or provoked intoxication. We observed at the ultrastructural level, in situ, the presence of Al, Fe, Ni, Cu, Zn in nuclei of different types of non‐intoxicated animal cells. Moreover, we measured the concentration of these metals in the nucleolus and chromatin and compared it with the concentration of P

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00577.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Peritoneal macrophages from normal mice which do not secrete interleukin 1 (IL 1) spontaneously release a factor with an approximate m.w. of 30,000‐35,000. In contrast, in the presence of silica only IL 1 is produced. IL 1 as well as this macrophage‐replacing factor (MRF) can restore the antibody response of macrophage‐depleted spleen cells. IL 1, however, is the only one that has the capacity to increase the proliferation of thymocytes. In every strain of mice studied, including nude mice, we observed a spontaneous release of MRF and a silica‐induced shift to the secretion of IL 1, except in lipopolysaccharide (LPS)‐hyporesponsive C3H/HeJ mice. Macrophages from these mice are unable to secrete MRF spontaneously, or IL 1 when stimulated with silica. The kinetics of the secretion of MRF and IL 1 appear to be similar. Macrophages, regardless of whether they have been stimulated to secrete IL 1, produce an intracellular IL 1‐like activity with an approximate m.w. of 15,000. In contrast, the intracellular PFC‐restoring activity is widely distributed in the 15,000‐60,000 m.w. range; one of these compounds could be related to IL 1 precursor and/or to MRF itself. Chromatofocusing and chromatography on Blue Trisacryl have led to a partial purification and resolution from a possible contamination by IL 1. Purified MRF induces, in conjunction with lymphokines, the differentiation of B cells into antibod

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00578.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Highly phosphorylated proteins detectable by their ability to bind bismuth ions were localized in rabbit fibroblasts before and during infection with Herpes simplex viruses type 1 and type 2. The bismuth tartrate procedure of Locke and Huie applied to glutaraldehyde‐fixed cells revealed a low level of bismuth binding in a restricted portion of the normal nucleolus in non‐infected cells. From 2.5‐17 hr post‐infection during virus development and maturation, the phosphorylated proteins were more widespread and the intensity of reaction was augmented. Bismuth deposits were then associated with virus‐modified pre‐existing structures including all of the nucleolar fibrils, the more abundant interchromatin granules, reduplications of some areas of the inner nuclear membrane and the Golgi apparatus. Virus‐induced structures which were stained included nuclear dense bodies, the teguments of enveloped virions and the contents of extranuclear enveloped structures devoid of capsids. Following detergent‐induced destruction of membranes, staining was lost from the nuclear envelope and cytoplasmic virions, which demonstrated that the highly phosphorylated proteins were tightly bound to nuclear and viral membranes. Bismuth staining of nitrocellulose sheets containing proteins extracted from whole cells revealed no reaction in normal cells but three positive bands were found in

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00579.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The subcellular localization of beta‐lactamase produced by a secretion‐cloning vector pIN‐III was studied by immunolabelling of frozen thin sections of Escherichia coli. Using double immuno‐gold detections and internal reference proteins, it is shown here that beta‐lactamase encoded by this vector can be exported and that its overproduction leads to aggregation within the periplasm. This aggregation induces the appearance of electron‐dense areas immunolabelled by the antiserum directed against the beta‐lactamase at the external side of the cytoplasmic membrane. The overproduced enzyme is also secreted to the medium in vesicles budding from the outer membrane o

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00580.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

Differentiation of preadipose 3T3‐F442A cells into adipose cells is accelerated by the addition of dihydrocytochalasin B. The effect of the drug on 3T3‐C2 cells is more marked: these cells are practically unable to differentiate in the absence of H2CB but a long‐term exposure to the drug enables the cells to accumulate lipid droplets in medium supplemented with fetal calf serum and insulin. During their differentiation under these conditions the 3T3‐C2 cells develop markers typical of adipose cells: glycerophosphate dehydrogenase, ATP‐citrate lyase, fatty acid synthetase and glycerophosphate acyltr

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00581.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The presence and abundance of calbindin in rat pancreatic islet cells was assessed by immunohistochemistry of either whole islets or purified B and non‐B islet cells, as well as by Western blotting of extracts derived from whole islets and purified B and non‐B islet cells. Immunohistochemistry of pancreatic sections indicated a higher calbindin content in non‐B cells, located at the periphery of the islets, than in the centrally located insulin‐producing B cells. Comparable results were obtained in purified islet cells. Likewise, scanning densitometry of the Western blots indicated that, relative to cell volume, the single calbindin band (Mr 27 kDa) was 5‐7 times higher in non‐B than in B cells. In the splenic lobe of chick pancreas, however, the opposite situation prevailed. Thus, insulin‐producing cells clustered in small roundish islets were more intensely labelled after exposure to anti‐calbindin serum than non‐B islet cells located in large and irregularly shaped islets. Nevertheless, even in the chick pancreas, non‐B islet cells contained an appreciable

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00582.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

In chicken, the main characteristic properties of muscle fibre types in slow anterior (ALD) and fast posterior (PLD) latissimus dorsii are acquired during post‐hatching development. At day 4 it becomes possible to distinguish between alpha' and beta' fibre types in ALD muscle. At the same time, mATPase staining and NADH‐TR activity permit recognition of alpha w and alpha R fibres within PLD muscle. During further development, muscle fibre typology progressively changes towards the adult slow and fast type. Chronic stimulation at a slow rhythm (5 Hz) of PLD prevents the change in relative proportions of alpha R and alpha W fibres within the muscle that occurs in normal post‐hatching development and increases the number of beta R fibres. Moreover, oxidative activity is increased in all muscle fibre types following stimulation. In ALD muscle, chronic stimulation at a fast rhythm (40 Hz) results in a decrease in oxidative activity and inhibits the differentiation of alpha' and beta' muscle fibre types. This study demonstrates that in young chicken, the pattern of activity influences the differenciation of fibre types in slow and fast mu

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00583.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY

摘要:

The energetic growth yields of Candida parapsilosis were compared with those of Saccharomyces cerevisiae as a function of the energy source in the presence or absence of antimycin A, an inhibitor of the second phosphorylation site. When glycerol was used as energy source, the energetic growth yields were quite similar in C. parapsilosis and S. cerevisiae. On the other hand, when experiments were carried out with glucose as energy source, although three phosphorylation sites were available, glucose was found to be a poor energy source for C. parapsilosis. When C. parapsilosis was grown in the presence of antimycin A, on glucose: YGluS = 3YGlu + AS and on glycerol: YGlyS = 2 YGly + AS. It was concluded that growth in the presence of antimycin A could occur due to the functioning of the third phosphorylation site. This result agrees with previous works indicating that in C. parapsilosis the alternative pathway merges into the main respiratory chain at the cytochrome c level. Although the doubling time of C. parapsilosis was much less temperature‐sensitive than that of S. cerevisiae, the energetic growth yield was the same at 13 degrees C and 28 degrees C, and consequently, the secondary pathway did not seem to be thermogeni

ISSN:0248-4900    

DOI:10.1111/j.1768-322X.1987.tb00584.x

出版商:Blackwell Publishing Ltd    

年代:1987

数据来源: WILEY