摘要:

Different methods for disintegration ofStreptococcus mitis, strain ATCC 903 were tested for extraction of hyaluronidase and aminopeptidase. Two methods were found effective, autolysis and freeze‐pressing. Reproducible conditions for the extraction of both enzymes were autolysis for 20 hours at 37° C in 0.05 M phosphate buffer at pH 6.8 in the presence of chloramphenicol (100 μg/ml). The amounts of enzymes released per unit of autolysed cells were not affected by the incubation temperature. Disintegration by freeze‐pressing reduced the specific activity of hyaluronidase by 70 per cent as compared to the autolytic procedure. Although the yield of aminopeptidase in extracts prepared by freeze‐pressing was approximately equivalent to that in autolytic extracts, the stability of the enzyme was

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00225.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

A colorimetric method has been tested for the determination of aminopeptidase in crude extracts ofStreptococcus mitis.This was done in order to evaluate the possibility of using this enzyme as an intracellular marker in studies concerned with the quantitation of cell lysis. No purification of the enzyme was applied since the determination of cell lysis by an intracellular enzyme marker is dependent on the accurate and rapid measurement of the enzyme activity in supernatants from autolyzing cultures. Under the assay conditions used the enzymic reaction proceeded at constant rate, proportional to enzyme concentration over a wide range. The rate of the enzymatic reaction was maximal at 35–40° C. The optimum pH for activity was 7.2. The enzyme was stable in the pH‐range 5.2–9.8. The rate of the reaction was decreased at high substrate concent

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00226.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The quantity of released and cell‐bound hyaluronidase and aminopeptidase was determined in cultures ofStreptococcus mitisgrown under controlled conditions of pH, anaerobiosis, stirring and temperature. The results indicated that the formation of hyaluronidase was completely repressed during exponential growth in the presence of glucose. Synthesis of hyaluronidase occurred after the exhaustion of glucose during an autolytic phase. Aminopeptidase activity of the cells increased both in the presence of glucose and in the autolytic phase. Both enzymes were released into the medium by an autolytic process. Controlled autolysis is suggested as a physiologically useful release mechanism for intracellular enzymes directed at high molecular weight substrates which are unable to pass through the cytoplasmic membrane. Neither selective release of hyaluronidase from intact cells nor extracellular activity could be demonstrate

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00227.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Hyaluronidase synthesis inStreptococcus mitis(ATCC 903) was completely repressed during anaerobic growth in glucose‐containing media. A rapid synthesis of hyaluronidase was observed when exponentially growing, repressed cells were transferred to a proteose‐peptone medium lacking fermentable carbohydrates. The synthesis started after a lag of approximately 10 min and continued at a constant rate for about 20 min. Chloramphenicol completely inhibited the synthesis. The period of synthesis of hyaluronidase at maximal rate increased with increasing concentrations of proteose‐peptone, while the rate of synthesis was not accelerated by proteose‐peptone concentrations above 1 per cent. Aminopeptidase activity of the cells also increased in proteose‐peptone medium. This increase was not inhibited by chloramphenicol or by puromycin. The aminopeptidase activity of the cellsincreased with increasing concentrations of proteose‐peptone. The increase of both enzymes was most rapid at pH 7.4–7.7. The cells released hyaluronidase and aminopeptidase solely by autolysis. Autolysis in proteose‐peptone medium was most rapid at pH 7.4–7.7 and was not affected by variations in the proteose‐peptone concentration or

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00228.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The synthesis of hyaluronidase, which is a constitutive, cell‐bound enzyme inStreptococcus mitisATCC 903, was investigated in cultures grown on different carbohydrates. Mannose was found to repress enzyme synthesis completely. The repressive effect of glucose was concentration dependent. After a period of complete repression for less than one generation, the rate of synthesis increased rapidly in 0.06 M glucose while complete repression continued in 0.17 M glucose. Sucrose, fructose and galactose repressed enzyme synthesis only to a limited extent. Of all carbohydrates tested sucrose had the least repressive effect and supported a maximal rate of growth. Cyclic AMP partially relieved glucose repression, particularly in media of low glucose concentration. The same effect was, however, also obtained with 5′ AMP. Theophylline did not increase the effect of cyclic AMP in counteracting glucose repression. Cyclic AMP caused 30–50 per cent inhibition of the synthesis of hyaluronidase in non‐growin

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00229.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Fusiformis necrophoruswas studied during growth in stirred fermentors at different pH levels and temperatures. At all studied conditions of cultivation a poly‐glucose compound, probably glycogen, was formed by the cells. There was an inverse relationship between cell growth and polysaccharide deposition, maximum glycogen content amounted to 60 per cent of the cell dry weight. In addition, carbohydrate storage was lower at pH 7 than at pH 5.5–6.0 and at 33° C in comparison with 37 and 39° C, indicating that both pH and temperature of the cultivation influence polysaccharide formation. In experiments with accelerated cell growth rate—induced by altered growth conditions—glycogen storage approached zero. It is concluded thatF. necrophoruspossess a previously unrecognized capacity for polysaccharide storage of such magnitude that it should be considered quantitatively in calculations of substrate grow

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00230.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The activity and distribution of proteinases and their inhibitors, lipases and amylases as well as the composition of the bacterial flora throughout small intestines of 20 slaughter pigs were investigated. It was demonstrated that the intestines were partly in contraction, partly in relaxation and that the contracted regions had no ingesta, only a scarce and mucous content. This type of content possessed no proteolytic activity while lipolytic and starch‐splitting activities as well as inhibitory substances against proteinase were always present. The contracted parts, which presented no regularity as to their length and localization, often appeared to be sterile. In the feed‐containing, relaxed regions of the intestines, the digestive enzymes examined were always present in high concentrations. Their activity was quite constant in all segments of the intestine. The proteolytic activity was partly based on trypsin. The main microorganisms found wereLactobacillussps., α‐haemolytic streptococci and lactosepositive enterobacteria (coliform). The quantitative bacteriological findings varied consid

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00231.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

The mycoplasmal flora of the urinary tract of 19 men and 21 women was investigated at autopsy. Mycoplasmas were isolated from the urethra of 9 bodies. One of the isolates was identified biochemically and serologically asM. primatum.This is the second isolation from man of this simian mycoplasma species. Three of the remaining isolates from the urethra were identified asM. hominis, one asM. fermentansand four asU. urealyticum. U. urealyticumwas isolated twice from the bladder urine. In one case, a strain ofU. urealyticumwas isolated from the cortex of a kidney with histologically demonstrable non‐specific inflammatio

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00232.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Seventeen mutants of a strain ofArthrobacter, producing altered amounts of extracellular protease, were isolated. One mutant had lost the ability to form wild type extracellular protease. Despite this loss, the mutant demonstrated proteolytic activity due to leakage of a thermolabile intracellular proteinase. Chemical, immunological and catalytic properties of this enzyme show that it is not related to the extracellular protease of the wild type.

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00233.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY

摘要:

Arvicola terrestris(vole rats), which belong to the vole family, have not been used previously for infection experiments with tubercle bacilli. In the present study the susceptibility of these animals toM. tuberculosisandM. bovishas been examined by intraperitoneal, subcutaneous and intravenous injection of varying doses of finely dispersed bacterial suspensions. Characteristic for the infection withM. bovisis a strong multiplication of the bacteria and the development of macroscopically visible caseous processes in liver, spleen and lungs, and in the enlarged lymph glands. The organs—in particular spleen, lungs and lymph glands—contain enormous numbers of tubercle bacilli. Doses as small as a few viable units are able to induce lethal infection. In contrast, the virulence ofM. tuberculosisis slight. The bacteria multiply sparsely and cause insignificant macroscopical changes in the organs. The course is markedly chronic unless use is made of giant doses administered intravenously. The susceptibility of vole rats to the two bacterial species resembles that of rabbits, and thus these animals can be used for differentiation purpo

ISSN:0365-5563    

DOI:10.1111/j.1699-0463.1974.tb00234.x

出版商:Blackwell Publishing Ltd    

年代:1974

数据来源: WILEY