Structural characteristics and distribution of satellite cells along crayfish muscle fibers.

The distribution of satellite cells (sc) in long-sarcomere muscle fibers from the carpopod extensor muscle of the crayfish (Astacus fluviatilis) has been studied electron-microscopically. The sc are spindle-shaped and are oriented parallel to the long axis of a fiber. The mean lengths of sc nuclei (17.00 microns) and that of myonuclei (18.35 microns) differ non-significantly. In older animals, the mean ratio of the number of sc nuclei to the total number of nuclei (sc nuclei + myonuclei) is 0.0716, 0.0848, and 0.034 for the tendon, central and shell segments, respectively. The corresponding values for younger animals are 0.158, 0.166, and 0.081. The mean numbers of sc nuclei per mm of a fiber are 94, 117, and 47 (older animals), and 164, 117, and 94 (younger animals) for the tendon, central and shell segments, respectively. The high incidence of sc per unit fiber length in crayfish may be related to the fact that crayfish muscle fibers have a much larger diameter than vertebrate muscle cells.     

Insoluble zinc-precipitated phosphomonoesterase from rat kidney

Summary The insoluble form of phosphomonoesterase precipitated by means of Zn²⁺-ions was prepared from the partially purified extract of rat kidney. The freeze-dried preparation of the precipitated enzyme is highly active and is stable on heating at 100°C.     

Lack of evidence for involvement of known human retroviruses in multiple sclerosis

The recent report by Koprowski et al. that human T-cell lymphotropic retroviruses (HTLVs) may be involved in the development of multiple sclerosis (MS) has aroused much interest. The report was based largely on immunological evidence, using enzyme-linked immunosorbent assays (ELISAs) with viral antigens or disrupted virions. We have accordingly sought confirmation by screening sera and cerebrospinal fluid (CSF) samples from MS patients against cell lines infected respectively with adult T-cell leukaemia (ATL) virus (ATLV/HTLV-I) of Japanese cells (MT-1 and MT-2 lines), our own isolate from British black patients with ATL, the MoT cell line which produce HTLV-II, and our own T-cell line containing a local isolate of acquired immune deficiency syndrome (AIDS) virus (C-LAV/HTLV-III). We have failed to find antibodies against these retroviruses in the sera or CSF. Furthermore, neither virus could be isolated from the peripheral white blood cells of two MS patients.     

Preadult lethality in four populations of Drosophila melanogaster treated with formaldehyde

Samples from 4 populations of D. melanogaster were treated with formaldehyde by the larval feeding method, and induced lethality was scored. The results showed relevant differences among the populations analyzed.     

The effect of hexosamine inhibitors on the secretion ofγ-globulin

Zusammenfassung Hemmung von Hexosamin vermag die Sekretion von-Globulin durch antikörperproduzierende Zellen unter in vitro Bedingungen nicht zu verhindern. Dies könnte darauf hinweisen, dass unter den gewählten Bedingungen kohlehydratfreie-Globulinmoleküle sezerniert werden.     

The mechanism of action of glyceraldehyde-3-phosphate dehydrogenase

Zusammenfassung Zur Erforschung des Wirkungsmechanismus einer komplexen Enzymreaktion vom Typus der GAPD können die mit der Wirkung dieses Enzyms verknüpften hypokatalytischen Vorgänge gewisse Anhaltspunkte geben. Als hypokatalytische Vorgänge werden die Reaktionen bezeichnet, die durch einen Teil des natürlichen aktiven Enzyms GAPD auf unspezifische Substrate ausgeübt werden. Auf Grund der Analyse einer solchen Reaktion, d. h. der Hydrolyse desp-NPA durch GAPD, wird die natürliche Funktion des Enzyms diskutiert.Während der Hydrolyse desp-NPA wird die-Aminogruppe eines Lysinrestes der GAPD spezifisch acetyliert, die möglicherweise einen Teil des Bindungsortes der GAPD bildet.Auf Grund unserer Experimente und mit Hinblick auf frühere Publikationen anderer Forscher wird ein mögliches Modell des aktiven Bereichs der GAPD vorgeschlagen.     

Ein Beitrag über die Art der Wirkung einiger Antituberkulotika

Summary The direct effect of any antituberculotics on pancreatic lipase was studied by the modified method ofWillstätter. The antituberculotics were found to activate the pancreatic lipase in the presence of Ca⁺⁺. Any cations, especially copper, decreases the lipase activity. Increasing antituberculotics concentration is accompanied by an increasing effect on the lipolytic action of lipase.