Proline excretion in Escherichia coli: A comparison of an argD + strain and a proline-excreting argD − derivative

In an attempt to deduce the physiological basis of proline excretion in argD ^– strains of Escherichia coli K12, several properties of an argD ⁺ (nonexcreting) and an argD ^– (excreting) derivative were compared. No difference was found in the transport or in the utilization of either proline or its immediate precursor, ¹-pyrroline-5-carboxylate (PCA). Furthermore, no differences were found in the physical or kinetic properties of partially purified preparations of the enzyme mediating the final step in proline biosynthesis, PCA reductase. The specific activity of PCA reductase was, however, consistently higher in crude extracts prepared from the argD ^– mutant.This work was supported by grants from the National Institutes of Allergy and Infectious Diseases (Public Health Service No. AI-10862) and The University of Connecticut Research Foundation (to C. M. B.). J. J. R. was supported by an NDEA Predoctoral Fellowship.     

Production of amylase(s) by Schwanniomyces castellii and Endomycopsis fibuligera

Schwanniomyces castellii and Endomycopsis fibuligera Produced extracellular amylase(s) when grown on various carbon sources and at different pH values. Both yeast species showed significant amylase synthesis in the presence of either maltose or soluble starch. On the other substrates tested (glucose, cellobiose, sucrose, trehalose, melezitose, raffinose, ethanol, glycerol) differences were found regarding growth and amylase production. Free glucose in the culture medium apparently inhibited enzyme synthesis. The pH range allowing maximal growth and amylase production was 4.5–6.0 for E. fibuligera and 5.5–7.0 for S. castellii.     

Partial trisomy 21 with 45 chromosomes due to translocation of two chromosomes 21 onto a chromosome 14 : 45,XX-14,-21,+t(14q21q21q) (author's transl)

A patient with the phenotype of trisomy 21 and increased activity of superoxide dismutase A is reported with partial trisomy for the distal portion of 21q. The exceptional feature in this case is a 45-chromosome karyotype due to the translocation of two chromosomes 21 onto the distal end of 14q.     

Methyl-4 formyl-7 cyclopenta(c)pyranne isole apres hydrolyse acide de Viburnum tinus

Viburtinal (4-methyl-7-formylcyclopenta(c)pyrane), yet unknown, was obtained by acid hydrolysis of the esters extracted from Viburnum tinus. Its structure was deduced by spectroscopic methods.     

Freezing of dCMP aminohydrolase in the activated conformation by glutaraldehyde.

dCMP aminohydrolase, which is an allosteric enzyme, was reacted with glutaraldehyde in the presence of the allosteric activator deoxycytidine-5′-triphosphate and of the competitive inhibitor deoxyadenosine-5′-monophosphate. The isolated modified enzyme is no longer sensitive to the effect of the allosteric ligands and shows kinetics typical of the activated enzyme. Gel electrophoresis demonstrated that glutaraldehyde, under our experimental conditions, does not produce intermolecular cross-links but fixes 80% of the enzyme in a stable hexameric form by intramolecular cross-links.The kinetic and molecular data are explained assuming that glutaraldehyde freezes the enzyme in the activated conformation.     

Parasites of Salmo trutta L. from the Tirino River. Part IV. Intermediate hosts of Cyathocephalus truncatus (Pallas, 1781) and Dentitruncus truttae Sinzar, 1955

During studies on helminth parasites of brown trout (Salmo trutta L.) from the river Tirino (L'Aquila - Italy), the intermediate hosts of Cyathocephalus truncatus (Pallas, 1781) and Dentitruncus truttae Sinzar, 1955 have been searched for. A total of 15,444 amphipoda belonging to the following 3 species: Echinogammarus roco Karman, 1973, Echinogammarus tibaldii Pinkster and Stock, 1970, and Gammarus italicus Goedmakers and Pinkster, 1977, have been dissected. E. roco, E. tibaldii and G. italicus were found infected with procercoid of Cyathocephalus truncatus (new hosts record and first procercoid record in Italy). E. roco, E. tibaldii and G. italicus were found infected with acanthella and cystacanth of Dentitruncus truttae (first record of intermediate hosts). Accordingly the ecology of the cestod C. truncatus and of the acanthocephalan D. truttae in their intermediate hosts has been studied considering principally the incidence and the seasonal occurence of the parasites.