Characteristics of the ultrastructural organization of Actinomyces rimosus and Actinomyces violocinereus in monocultures and in an association producing extracellular proteases

The ultrastructural organization of Actinomyces rimosus and Actinomyces violocinereus was compared in monocultures and in associations. The cells of the two species can be discriminated by certain cytological characteristics. A rimosus predominated under the studied conditions and periods of growth. This organism had growth processes disordered (intrahyphal growth). A. violocinereus was characterized by the following processes in the association: peptidoglycan hypersynthesis, formation of calloses of the cell wall which occurred in parallel to hypertrophy of mesosomes, a loss of the capability to form capsules, and delayed spore formation. The reduced synthesis of granular and fibrillar material indicated that these products were not associated with exoprotease. The enzymatic activity was higher and could be detected in earlier in the association than in the monoculture of A. rimosus.     

The relationship of common saprophytic and pathogenic fungi to the Forssman and other antigens of the sheep erythrocyte

Summary 1) Culture filtrates and mats from 20 different species of fungi cultured on Sabouraud dextrose broth and asparagine synthetic medium were examined for the presence of Forssman activity utilizing a hemolysis inhibition test.2) None of the uninoculated media contained any Forssman activity.3) Seventeen of the fungi exhibited no such activity.4) Single preparations of mats ofCandida tropicalis, Fusarium moniliforme andHistoplasma capsulatum appeared to contain Forssman activity. Further studies, however, employing different preparations of these fungi in the hemolysis inhibition test and the initial preparations in an hemagglutination inhibition test did not corroborate the original findings.5) Preparations of three of seven different fungi, none of which possessed Forssman activity, were found to contain blood group A activity.6) Preparations of six different fungi without Forssman activity, including the three with the blood group A properties, were found not to inhibit the anti-sheep erythrocyte agglutinins in the serum from a patient with infectious mononucleosis.7) The importance of the sheep erythrocyte as a heterogenetic antigen is discussed.This study was supported in part by USPHS GRANTS A1-01478-07, 5 T1 A1 52-05 and 5T1-AM-5265-05 and the Dermatologic Research Foundation of California, Inc.     

Isolation and properties of carboxypeptidase from Streptomyces spheroides, strain 35

Extracellular carboxypeptidase was isolated from culture filtrates of Str. spheroides strain 35, using affinity chromatography on bacitracin-silochrome, bacitracin-Sepharose and CABS-Sepharose. The electrophoretically homogenous enzyme was obtained with a 44% yield and 4160-fold purification. The enzyme-molecular weight is 33,000 Da; pI is 4.7. The amino acid composition of carboxypeptidase is as follows: Asp43, Thr30, Ser35, Glu33, Pro30, Gly47-50, Ala38, 1/2 Cys5-6, Val16, Met2, Ile11, Leu15, Tyr8, Phe10, Lys10, His6, Arg9. The enzyme shows an activity optimum at pH 7.5 is stable at pH 6-8, is completely inhibited with EDTA and can be reactivated by Ca2+. The carboxypeptidase from Str. spheroides strain 35 has a dual substrate specificity, i. e., it splits N-substituted di-, three- and tetrapeptides having both neutral and basic amino acids at the C-ends similar to mammalian carboxypeptidases A and B. The enzyme belongs to the family of metallocarboxypeptidases; its properties are very similar to those of carboxypeptidase S from Str. griseus K-1 and of carboxypeptidase T from Thermoactinomyces sp.     

Quantification of the pathways followed in hepatic glycogen formation from glucose

Quantitative contributions of the direct and indirect pathways to liver glycogen formation from a glucose load have been estimated from 1) the distribution of label in glycogen formed from specifically carbon-labeled loads of glucose, 2) the specific activity of the glycogen compared with that of the circulating glucose, 3) the 3H:14C ratios in glycogen formed from loads specifically labeled with 3H and 14C, 4) the incorporation of 3H from 3H2O into the glycogen, and 5) the balance of glucogenic substrates across the splanchnic bed. A number of assumptions are made in the use of each of these methods. Estimates have been made for animals and humans fasted overnight or longer. Results obtained with the different methods are compared. Under these conditions, the contribution of the pathways appears to be determined by the size of the load, with larger contributions of the indirect pathway occurring with smaller loads.