Zur Mikromorphologie der neuromuskulären Verbindung der afibrillär-tonischen Skeletmuskelfaser des Frosches (Rana Temporaria L.)

Zusammenfassung Morphologische Unterschiede zwischen fibrillär-phasischen und afibrillärtonischen Skeletmuskelfasern des Frosches werden elektronenmikroskopisch abgebildet und beschrieben. An Synapsen afibrillär-tonischer Fasern werden neben dem synaptischen Axon sehr viel dünnere para-Axone aufgezeigt. Ihre Bedeutung als leitende Axone der terminaisons en grappes oder als Anteile akzessorischer Fasern in der tonischen Synapse wird diskutiert.Durchgeführt mit Unterstützung durch die Deutsche Forschungsgemeinschaft und das Kultusministerium des Landes Nordrhein-Westfalen.     

Cyclic AMP-dependent regulation of activities of synthetase and phosphodiesterase of 2′,5′-oligoadenylate in NIH 3T3 cells

Summary Dihydrofolate synthetase (EC 6.3.2.12) from N. gonorrhoeae was isolated and enzyme characteristics were determined. The purified enzyme was found quite stable when stored at –60 °C. About 50% of the enzyme activity wag destroyed within 6 weeks when kept at 4 °C. Maximum velocity was observed at pH 9.3. The enzyme required a monovalent cation, K⁺ or NH₄ ⁺ , and divalent cation, Mg²⁺ or Mn²⁺ for its function. ATP at 5 mM concentration gave maximum activity. K_m values for dihydropteroate and L-glutamate at pH 9.3 were 3.5 × 10^–5 M and 6.5 × 10^–4 M, respectively. Patterns of product inhibition by dihydrofolate were found to be non-competitive with respect to dihydropteroate, having a K_i value of 5.1 ± 0.8 × 10^–4 M, and competitive with respect to L-glutamate, having a K_i value of 6.2 × 10^–4 M.     

Immunocytochemical and electrophoretic studies on the localization of the major haemolymph proteins (ceratitins) inCeratitis capitata during development

Summary The developmental profile of the major haemolymph proteins (ceratitins) inCeratitis capitata was studied. Ceratitin concentration in the haemolymph decreases dramatically during the last days of pupal life, while the amounts of ceratitins in whole organism extracts remain unchanged. By electrophoretic, immunological and immunofluorescence techniques it was revealed that ceratitins are reabsorbed by the fat body and a fraction of them is deposited in the cuticle. The possible role of ceratitins is discussed.     

Calliphorin,a major protein of the blowfly: Correlation between the amount of protein,its biosynthesis,and the titer of translatable calliphorin-mRNA during development

The amount of calliphorin, its biosynthesis, and the levels of translatable calliphorin-mRNA have been determined during the postembryonic development of Calliphora vicina R.-D. The amount of calliphorin increases in early third-instar larvae, reaching maximal levels in 6-day-old animals. It continuously decreases during late larval and pupal development to approximately one-half of the maximal levels and abruptly sinks during eclosion. The biosynthesis of calliphorin takes place only in 3- to 5-day-old larvae. Poly(A)⁺-RNA has been translated into proteins in a wheat germ cell-free system. Calliphorin-mRNA can be detected in 3- to 7-day-old larvae; maximal concentrations are observed in 4- and 5-day-old animals. No calliphorin-mRNA can be detected in prepupae, pupae, or imagos. The biosynthesis of calliphorin in blowfly larvae stops before a decrease of translatable calliphorin-mRNA is observed. This finding raises the question of the mechanism of in vivo inactivation of this specific mRNA.     

Target cells for the activity of a synthetic adjuvant: muramyl dipeptide.

Muramyl dipeptide (MDP), a synthetic adjuvant, increased the primary response of CBA mice to sheep red blood cells (SRBC). In reconstituted irradiated recipients, cooperation between T and B lymphocytes was required for the expression of adjuvant activity and MDP increased the efficiency of SRBC-educated T cells. The role of T-derived lymphocytes in mediating the MDP adjuvant activity was also demonstrated in irradiated mice and in mice reconstituted with various splenic cellular types of donors which had received SRBC and MDP 24 hr earlier. In our experiments, the macrophage did not seem to be involved, since MDP did not increase the phagocytic capacity of peritoneal exudate cells and MDP- and SRBC-pretreated macrophages had no increased ability to induce an anti-SRBC immune response. These results demonstrate the importance of T lymphocytes as mediators of the adjuvant activity of MDP.     

A rapid method for the large scale purification of the intermediate filament protein vimentin by single-stranded DNA-cellulose affinity chromatography

A new method is described for the purification of the intermediate filament protein vimentin from Ehrlich ascites tumor cells using single-stranded DNA-cellulose affinity chromatography. The procedure is rapid and allows the large scale isolation of the protein. Partial characterization of vimentin shows that it has a molecular weight of 58000 and an apparent pI of 5.3. It can be degraded by the vimentin-specific, Ca²⁺-activated proteinase which results in the production of a characteristic set of degradation products. The vimentin also cross-reacts with the intermediate filament protein monoclonal antibody, α-IFA.     

Temperature dependence of the transition enthalpy of core particle DNA and of long DNA

The denaturation of short (145 base pairs) and long (about 8000 base pairs) DNA moelucules has been studied by adiabitic differential microcalorimetry in solutions with different NaCl content. It is found that the enthalpy of denaturation of short DNA is more sensitive to changes in T_m than that of long DNA. A comparison with other data is also given.     

Specific antibodies and mycobacterial antigens in pulmonary tuberculosis patients sera. Note I

206 sera collected from different groups of subjects were analyzed by immunoenzymatic methods regarding the content of Mycobacterium tuberculosis specific antibodies and mycobacterial antigens. The results underlined that two assays offered improved serologic diagnosis of tuberculosis over a single antibody test. BCG vaccination interferes with serologic tests for tuberculosis when polyspecific antibodies or mixture of common and specific antigens are used as immunologic reagents. A mycobacterial antigens circadian variation in correlation with vesperal fever in tuberculous patients was not revealed. The mycobacterial antigens seem to become undetectable, in sera, after 6 months of efficient treatment.