摘要:

Physiological and biochemical properties of the liquid exuded from developing sclerotia ofSclerotinia sclerotiorumwere studied. In aging cultures the weight of dry matter, total proteins, free ammonia, crude lipid, potassium, and magnesium decreased, whereas sodium and the pH of the liquid increased. In general, the free amino acids decreased. Specific activities of catalase, peroxidase, polyphenoloxidase, and β-glucosidase did not follow similar trends. Catalase and β-glucosidase activities were high during the pigmentation phase of sclerotia development. Trehalase activity was not detected. Disc-gel electrophoretic patterns for proteins, peroxidases, and polyphenoloxidases are shown. Alpha-ketoglutaric, glyoxylic, malic, and succinic acids were detected. An hypothesis to account for the presence of large drops of liquid on the surface of developing sclerotia is proposed.

ISSN:0008-4166    

DOI:10.1139/m73-011

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Twelve cultures of Hyphomycetes capable of growth upon the ethane component of natural gas were isolated from raw sewage by a continuous enrichment technique. In addition, all isolates also grew on propane andn-butane but not methane. These cultures are described and their taxonomic position discussed. Four were tentatively placed inGraphium; three were identified asPhialophora jeanselmei(Langeron) Emmons; the remaining five are similar toAcremoniumsensu Gams.

ISSN:0008-4166    

DOI:10.1139/m73-012

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The biosynthesis of branched-chain fatty acids by cell-free extracts ofBacillus subtilishas been studied.The extract ofB.subtilisrequires α-ketoisovalerate, DPNH, malonyl CoA, TPNH, and dithiothreitol for the synthesis of 14-methylpentadecanoic acid (major acid). Concentrations of α-ketoisovalerate, malonyl CoA, and TPNH giving half maximum activity are 2 μM, 6 μM, and 250 μM, respectively. Relative activity of three α-keto acids, α-ketoisovalerate, α-ketoisocaproate, andL-α-keto-β-methylvalerate for the fatty acid synthesis is in the ratio of 1/2.4/5.3.TheB.subtilisextract can be divided into a heat-labile enzyme fraction and a heat-stable fraction, both of which are essential for the synthesis. The enzyme is soluble; all the activity remains in the supernatant when this fraction is treated by ultracentrifugation. The heat-stable factor can be replaced by a similar fraction from an extract ofEscherichia coli. The amount in a crude extract ofB.subtilisis, however, insufficient to give the full activity to the enzyme fraction.TheB.subtilissystem incorporates isobutyryl CoA into fatty acids, but not acetyl CoA. The reverse is true ofE.coli. Hence the absence of branched-chain acids inE.coliis due both to the lack of α-ketoisovalerate dehydrogenase and to the substrate specificity of the enzyme toward CoA esters.

ISSN:0008-4166    

DOI:10.1139/m73-013

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A mycovirus has been purified from mycelia ofPenicillium chrysogenumby isopycnic centrifugation in sucrose and in CsCl. Viral particles band with a buoyant density of 1.20 in sucrose and 1.38 in CsCl. Particles have icosohedral symmetry, are 35 nm in diameter, and have an absorption profile characteristic of nucleoprotein. One enzymatic activity, RNA polymerase, is associated with the purified mycophage. Nucleic acid extracted from purified virus has a buoyant density in CS2SO4of 1.61, a molar extinction coefficient of ϵp(258 nm) of 7200, as20,wof 13.0, and a pattern of circular dichroism characteristic of double-helical ribonucleic acid. Molecules of this double-stranded ribonucleic acid (dsRNA), examined by electron microscopy, have a mean contour length of 0.86 μm which corresponds to a molecular weight of about 2.0 × 106daltons. This dsRNA is resolved further by acrylamide gel electrophoresis into three closely spaced bands. Thermal denaturation of the viral dsRNA is dependent on ionic strength and gives a linear relationship with the negative logarithm of the sodium ion concentration.

ISSN:0008-4166    

DOI:10.1139/m73-014

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The map order of several genes on the chromosome ofStaphylococcus aureus,S.epidermidis,S.muscae, andS.lactishas been determined, revealing few significant differences. In contrast, ratios of the total number of mutants induced in various genes have demonstrated appreciable differences among these four organisms. Such ratios may be a useful taxonomic tool for comparing deoxynucleotide structure of a functionally similar gene in various strains and species.

ISSN:0008-4166    

DOI:10.1139/m73-015

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

A genomic map ofBrucella abortus, strain 19, containing the relative locations of 19 genes has been derived by use of marker frequency analysis. Under the conditions used, the chromosomal replication time was approximately 60 min and the mass duplication time was 216 min.

ISSN:0008-4166    

DOI:10.1139/m73-016

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Preliminary evidence has been obtained which suggests that the intracellular invertase ofSaccharomyces cerevisiaemay not be localized in the vacuole per se. Alkaline phosphatase, an intracellular enzyme, and acid protease, a typically lysosomal enzyme, both showed high specific activity in the vacuole fraction prepared by equilibrium centrifugation of lysed sphaeroplasts in Ficoll gradients. Invertase activity has been found to be associated with vacuoles only when glucose-repressed cells are derepressed. Cells derepressed for invertase biosynthesis contained a population of vesicles which were virtually absent from the repressed cells. Evidence is presented which strongly suggests that these vesicles rather than the vacuoles are the vehicle by which invertase is secreted from the cell.

ISSN:0008-4166    

DOI:10.1139/m73-017

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Five successive generations of tumors have been produced in inbred Syrian hamsters after initial inoculation of SV40-transformed Cl2TSV5and RHaT cell lines.SV40 could be rescued by cell fusion with inactivated Sendai virus from cell cultures of all five tumor generations. T-antigen was detected in all cultures by fluorescent antibody staining.An increased capacity for fusion of SV40-transformed cells after successive passages in hamsters has been observed.In addition to monkey kidney cells, bovine and lapine kidney cells have been successfully used for SV40 rescue by cell fusion.

ISSN:0008-4166    

DOI:10.1139/m73-018

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

Submerged cultures of 10 thermophilic fungi, grown at 45° in a medium containing 4% casein, 0.4% glucose, 0.3% yeast extract and salts, were surveyed for extra- and intra-cellular protease production. The yield, thermostability, pH optimum, and inhibitor sensitivity of the crude proteases were determined in each case. The inhibitors used were diisopropylfluorophosphate (DFP), ethylenediaminetetraacetic acid (EDTA), andp-chloromercuribenzoate (pCMB).Seven of the thermophiles produced a substantial quantity of protease, particularly extracellular protease. In comparison to mesophilic fungi most proteases appeared to be unusually thermostable. Neutral and alkaline proteases were most common, as were proteases inhibited by DFP andpCMB. Finally in most of the cases a sensitivity to more than one inhibitor indicated the existence of more than one type of protease.

ISSN:0008-4166    

DOI:10.1139/m73-019

出版商:NRC Research Press    

年代:1973

数据来源: NRC

摘要:

The effects of pH on the activity of a highly purified constitutive alkaline phosphatase fromNeurospora crassawere studied. The pH optimum for the reaction was a linear function of the logarithm of the substrate concentration, as is typical for alkaline phosphatases. Other pH effects were complex andVmaxor pKmversus pH plots differed for the two substrates used and from similar plots prepared with the repressible enzyme from this or other sources. TheKmforp-nitrophenyl phosphate increased 200-fold over the pH range 7.0–8.7. Substrate inhibition was more pronounced at low than high pH. Lineweaver-Burk plots were non-linear at high substrate concentration but linear at low substrate concentration. Substrate inhibition by glucose 6-phosphate was not observed.The data are consistent with the hypothesis that hydroxyl ion is a second substrate for the enzyme and is an activator at high and an inhibitor at lowp-nitrophenyl phosphate and glucose 6-phosphate concentrations. A Bi-Bi mechanism with random substrate addition, dead-end substrate, and product inhibition, having ordered release of products is discussed and is consistent with kinetic and pH studies. A two-site model for the active center of the enzyme is presented to account for alternate product inhibition data.

ISSN:0008-4166    

DOI:10.1139/m73-020

出版商:NRC Research Press    

年代:1973

数据来源: NRC