A survey of microorganisms for thermonuclease production

1980 ◽  
Vol 26 (4) ◽  
pp. 532-535 ◽  
Author(s):  
C. E. Park ◽  
A. de Melo Serrano ◽  
M. Landgraf ◽  
J. C. Huang ◽  
Z. Stankiewicz ◽  
...  

A total of 1204 cultures comprising 16 genera were surveyed for production of thermonuclease (TNase) in milk. Cultures other than Staphylococcus capable of TNase production were restricted to two genera, Streptococcus and Bacillus. Nineteen percent of 338 group D streptococci comprising four species (85% of which were Streptococcus faecalis) and 17% of 60 streptococci belonging to other groups produced TNase. Nine percent of 130 Bacillus cultures comprising six species produced the enzyme. On the other hand, 99% of coagulase-positive staphylococci produced TNase and only 18% of the coagulase-negative staphylococci produced the enzyme. The amount of TNase produced by streptococci and bacilli was significantly lower than that produced by coagulase-positive staphylococci. The pH profile of the streptococci and Bacillus TNases was similar to that of the staphylococcal TNase; each enzyme exhibited a minor peak at pH 7.0 and a broad major peak ranging from pH 8.5 to 10. The nuclease produced by coagulase-positive Staphylococcus was more heat stable than the nucleases produced by Streptococcus and Bacillus; there was little loss in activity of the staphylococcal enzyme after 60 min at 100 °C, whereas 50% of the activity of the streptococcal and Bacillus nucleases was destroyed in 40–60 min and 60–80 min, respectively.

1990 ◽  
Vol 22 (1) ◽  
pp. 113-119 ◽  
Author(s):  
William H. James

SummaryDuring the first half of this century, the seasonal pattern of births in European countries showed a major peak in the spring and a minor peak in the autumn. In contrast, the pattern in the US was of a minor peak in spring and a major peak in autumn. Over the last 20 years, the pattern in England and Wales has changed to resemble the US pattern, and the same seems to be true of several other European countries. A hypothesis is offered to account for the difference between the European and the US patterns and for the change from one to the other in some countries.The magnitude of seasonality correlates positively with latitude: it is suggested that this is partially consequent on variation in luminosity.


1991 ◽  
Vol 7 (2) ◽  
pp. 221-232 ◽  
Author(s):  
George Idodo-Umeh ◽  
Reginald Victor

ABSTRACTSome aspects of the ecology of bagrid catfishes in River Ase, southern Nigeria were studied for a period of two years. Nine species of Bagridae were recorded and these accounted for 15.0% of the number and 24.4% of the weight of all fish captured. Chrysichthys nigrodigitatus and Chrysichthys auratus longifilis were the principal species. C. nigrodigitatus was a rainy season species, while C. auratus longifilis was abundant in both dry and rainy seasons. Both species showed a major peak in catches between 0600 and 0900 h. C. nigrodigitatus exhibited a minor peak in catches between 1500 and 2100h, while C. auratus longifilis showed a minor peak between 1500 and 1800h. The spatial distribution of C. nigrodigitatus and C. auratus longifilis populations was heterogeneous. Bagrid fishes were an important component in the fish yield of the study river and its species composition has been compared with those of other Nigerian waters. The distribution and abundance of C. nigrodigitatus and C. auratus longifilis are discussed in detail.


1994 ◽  
Vol 300 (1) ◽  
pp. 229-236 ◽  
Author(s):  
T O Berg ◽  
P E Strømhaug ◽  
T Løvdal ◽  
P O Seglen ◽  
T Berg

Lysosome-disrupting enzyme substrates have been used to distinguish between lysosomal and prelysosomal compartments along the endocytic pathway in isolated rat hepatocytes. The cells were incubated for various periods of time with 125I-labelled tyramine cellobiose (125I-TC) covalently coupled to asialoorosomucoid (AOM) (125I-TC-AOM); this molecule is internalized by receptor-mediated endocytosis and degraded in lysosomes, where the degradation products (acid-soluble, radio-labelled short peptides) accumulate, Glycyl-L-phenylalanine 2-naphthylamide (GPN) and methionine O-methyl ester (MOM), which are hydrolysed by lysosomal cathepsin C and a lysosomal esterase respectively, both diffused into hepatocytic lysosomes after electrodisruption of the cells. Intralysosomal accumulation of the hydrolysis products (amino acids) of these substrates caused osmotic lysis of more than 90% of the lysosomes, as measured by the release of acid-soluble radioactivity derived from 125I-TC-AOM degradation. The acid-soluble radioactivity coincided in sucrose-density gradients with a major peak of the lysosomal marker enzyme acid phosphatase at 1.18 g/ml; in addition a minor, presumably endosomal, acid phosphatase peak was observed around 1.14 g/ml. The major peak of acid phosphatase was almost completely released by GPN (and by MOM), while the minor peak seemed unaffected by GPN. Acid-insoluble radioactivity, presumably in endosomes, banded (after 1 h of 125I-TC-AOM uptake) as a major peak at 1.14 and a minor peak at 1.18 g/ml in sucrose gradients, and was not significantly released by GPN. GPN thus appears to be an excellent tool by which to distinguish between endosomes and lysosomes. MOM, on the other hand, released some radioactivity and acid phosphatase from endosomes as well as from lysosomes.


1988 ◽  
Vol 117 (1) ◽  
pp. 123-132 ◽  
Author(s):  
T. A. Howlett ◽  
G. M. Besser ◽  
L. H. Rees

ABSTRACT The prodynorphin-derived opioids, dynorphin (DYN) and α-neoendorphin (αNE) were studied in 24 human phaeochromocytomas and related tumours. Nineteen tumours, extracted in HCl (0·1 mol/l), contained concentrations of immunoreactive DYN (ir-DYN) ranging from < 0·5 to 794 pmol/g wet weight. None of the extracts in HCl contained ir-αNE (all < 2·4 pmol/g). Sephadex G-50 gel filtration chromatography of ir-DYN in HCl (0·1 mol/l) extracts of six tumours revealed three small peaks of ir-DYN of higher molecular size (approximately 12 000, 6000 and 3000 daltons), a minor peak of ir-DYN eluting just after DYN(1–17), and a broad major peak, consisting of at least three components, which was significantly retarded and eluted after the salt volume of the column. High-pressure liquid chromatography (HPLC) of these extracts revealed multiple peaks of ir-DYN, most of which did not coelute with any synthetic DYN peptides. On both gel filtration chromatography and HPLC, one of the minor peaks coeluted with DYN(1–32). None of the peaks of ir-DYN coeluted with DYN(1–17) which had been acetylated using acetic anhydride. Extracts of the same tumours in acetic acid (0·1 mol/l) yielded similar values for ir-DYN content, but parallelism in the assay was improved. Sephadex G-50 chromatography revealed a different pattern of ir-DYN with a major peak coeluting with DYN(1–17) and, in two tumours, a minor peak coeluting with DYN(1–8). Studies with HPLC revealed, however, that substantial degradation of synthetic DYN occurred during extraction in acetic acid (0·1 mol/l) in spite of the precautions taken. Phaeochromocytomas frequently contain ir-DYN in concentrations which may approach that of the mammalian pituitary. These tumours did not, however, contain ir-αNE and, with the possible exception of a small amount of DYN(1–32), the ir-DYN present did not correspond with any known sequences. Thus, whilst prodynorphin is expressed in phaeochromocytomas, it does not seem to be processed to the usual end-products, and post-translational modifications therefore seem likely. Enzymatic degradation of DYN may occur during extraction in acetic acid (0·1 mol/l), and this medium should, therefore, be avoided in studies of such labile peptides. J. Endocr. (1988) 117, 123–132


1980 ◽  
Vol 7 (3) ◽  
pp. 453 ◽  
Author(s):  
HA Ford

'New Holland honeyeaters Phylidonyris novaehollandiae moult their primary feathers between mid- October and late April. Most adults probably have completed their moult by February, some immatures moult later. Individual birds may take over 100 days to complete moulting their primaries. The secondary and tail feathers are moulted towards the end of the primary moult and slightly after it. Limited data for 15 other species suggest that they moult at a similar time and for a similar duration. Breeding, in the Adelaide area, occurred in all months of the year in at least some species of honeyeaters, with a major peak from July to November, and a minor peak in April and May. Insectivorous species breed somewhat later than nectarivorous species and breed less often in autumn. Breeding of the former group may be influenced chiefly by increasing temperature in spring, whereas autumn rainfall probably influences the timing of peak nectar production. Although there is some overlap between the extensive breeding seasons and moulting periods of honeyeaters I have no evidence that individual honeyeaters breed while they are moulting.


1986 ◽  
Vol 64 (4) ◽  
pp. 315-322 ◽  
Author(s):  
Thomas-Louis Tremblay ◽  
Jacques Lapointe

A single peak of tRNAGlu is obtained upon chromatography of unfractionated tRNA from Escherichia coli on DEAE-Sephadex A-50 if this tRNA was previously renatured, whereas two peaks of tRNAGlu are resolved if the sample chromatographed is a mixture of native (renatured) and denatured tRNA. Higher resolution analysis of native E. coli tRNA by RPC-5 chromatography showed that most of the tRNAGlu is present in one peak, eluted shortly after a minor peak containing about or less than 5% of the total amount of tRNAGlu; these two peaks were also observed with commercially available tRNAGlu purified from E. coli. When denatured, the tRNAGlu present in each of these two peaks was eluted from the RPC-5 column at a much lower salt concentration. The properties of the denatured conformers obtained from native tRNAGlu present in the major and minor peaks, and the variation, with growth conditions of E. coli, in the relative amount of tRNAGlu in the minor peak suggest that the tRNAGlu present in the minor peak is an undermodified form of the tRNAGlu present in the major peak. This [Formula: see text] (or [Formula: see text] when modified in the anticodon) would then be the only tRNA species acceptor of glutamate in E. coli.


2017 ◽  
Vol 13 (12) ◽  
pp. 84
Author(s):  
Vincent Kadjo ◽  
Assoi O. Etchian ◽  
Jean-Noel Yapi ◽  
Atcho Otchoumou ◽  
Aka Jean-Paul Agnissan ◽  
...  

The parameters of growth, mortality, the exploitation and the recruitment of Atya scabra (Leach, 1815) as traditionally fished in the Bia river, were studied. These parameters were determined from the size frequencies by the FiSAT II software. The results obtained at the specimens of Aboisso were:= 156,45 mm, K = 1,50 year -1, Φ' = 4,56, Z = 5,72 year -1, M = 1,48 year -1, F = 4,24 year -1 and E = 0,74 year -1. In Biaka, theestimated values were: L = 140,7 mm, K = 0,68 year -1, Φ' = 4,13, Z = 1,52year -1, M = 0,91 year -1, F = 0,61 year -1 and E = 0,40 year -1 . Aboisso specimens have a higher growth performance index (Φ') than Biaka's and a weak longevity (tmax = 2 years) compared to Biaka (tmax = 4.41 years). Shrimps are under exploited in the locality of Biaka (E 0.5). Total mortality is higher in Aboisso than in Biaka. However, the survival rate recorded in Aboisso (S = 0.003 years) is lower than that of Biaka (S = 0.22 years). Recruitment is continuous throughout the year, with two peaks (a major peak in September and a minor peak in February) in Aboisso. As for Biaka, the presence of a normal distribution indicates that recruitment is single. These results will serve as a database for rational management of A. scabra.


1989 ◽  
Vol 21 (3) ◽  
pp. 321-327 ◽  
Author(s):  
S. S. Halli

SummaryEarlier studies on the seasonality of births indicate that a major peak occurs in August and September and a minor peak in January and February. This study uses the 1984 Canadian Fertility Survey data on reproductive history to examine birth and pregnancy seasonalities, and shows that the ‘worst’ months for births are January and February and the ‘best’ months are March, April and May. There is no systematic pattern in the seasonality of pregnancies, possibly because effective birth control allows couples to plan the timing of births.


1963 ◽  
Vol 9 (1) ◽  
pp. 93-101 ◽  
Author(s):  
Takamasa Shimizu ◽  
B. W. Griffiths ◽  
L. Greenberg

Coagulase-positive staphylococci produce discrete compact colonies when grown in a semisolid medium containing rabbit serum or plasma. In contrast, the same organisms produce elongated diffuse colonies when grown in the basal medium. Coagulase-negative staphylococci, on the other hand, produce diffuse colonies in both media, but were found to produce compact colonies when the basal medium was enriched with homologous antibody-containing serum.Sixty-three strains were studied, 56 of which were coagulase positive. The strains were from different sources—human, canine, bovine, and equine. A number of strains did not conform to the normal pattern. Attempts were made to establish the relationship between agglutinin titers and colony-compacting antibodies.


1980 ◽  
Vol 26 (6) ◽  
pp. 722-725 ◽  
Author(s):  
N. Bissonnette ◽  
R. A. Lachance ◽  
J. Goulet ◽  
M. Landgraf ◽  
C. E. Park

Of 105 thermonuclease-positive (TNase-positive) cheese samples comprising 13 types, 92 (87.6%) contained coagulase-positive staphylococci, whereas 9 (8.6%) contained microorganisms other than staphylococci as the major contaminants. Of the latter group, six samples contained Bacillus spp. comprising three species (B. cereus, B. licheniformis, and B. subtilis), and three contained mainly enterococci (Streptococcus faecalis), which were proven to be TNase producers. The organisms responsible for TNase production in the other four samples (3.8%) are not known, because isolates from these samples failed to produce the enzyme. Unlike staphylococcal TNase, a greater part of nonstaphylococcal TNase remains in the cheese homogenate after extraction of the enzyme at pH 3.8 instead of pH 4.5.


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