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1.
Servaas Visser Charles J. Slangen Fred A. Exterkate Gerrie J. C. M. de Veer 《Applied microbiology and biotechnology》1988,29(1):61-66
Summary The specificity of a cell wall proteinase (PI) from Streptococcus cremoris strain HP in its action on bovine -casein was determined. To this end an enzymic digest (pH 6.2; 15° C) of -casein was brought to pH 4.6 and the soluble fraction separated by semi-preparative reversed-phase HPLC. Purified peptides were analyzed by amino acid and end-group analysis. Ten chromatographic components were identified, which together accounted for at least seven cleavage sites all being located in the C-terminal fifty-residue part of -casein. In five cases it concerned a Gln-X or X-Gln peptide linkage. The specificity of this proteinase from S. cremoris HP shows similarity to that reported for a cell wall proteinase from S. lactis NCDO 763 in its action on -casein.Presented at the second FEMS Symposium on Lactic Acid Bacteria held in 1987 at Wageningen, Netherlands 相似文献
2.
High level of divergence of male-reproductive-tract proteins, between Drosophila melanogaster and its sibling species, D. simulans 总被引:1,自引:0,他引:1
We compared male-reproductive-tract polypeptides of Drosophila melanogaster
and D. simulans by using two-dimensional gel electrophoresis. Approximately
64% of male-reproductive-tract polypeptides were identical between two
randomly chosen isofemale lines from these two species, compared with 83%
identity for third-instar imaginal wing-disc polypeptides. Qualitatively
similar differences were found between reproductive tracts and imaginal
discs when D. sechellia was compared with D. melanogaster and with D.
simulans. When genic polymorphism was taken into account, approximately 10%
of male- reproductive-tract polypeptides were apparently fixed for
different alleles between D. melanogaster and D. simulans; this proportion
is the same as that found for soluble enzymes by one-dimensional gel
electrophoresis. Strikingly, approximately 20% of male-reproductive- tract
polypeptides of either D. melanogaster or D. simulans had no detectable
homologue in the other species. We propose that proteins of the Drosophila
male reproductive tract may have diverged more extensively between species
than have other types of proteins and that much of this divergence may
involve large changes in levels of polypeptide expression.
相似文献
3.
Comparative Study of Action of Cell Wall Proteinases from Various Strains of Streptococcus cremoris on Bovine αs1-, β-, and κ-Casein
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Servaas Visser Fred A. Exterkate Charles J. Slangen Gerrie J. C. M. de Veer 《Applied microbiology》1986,52(5):1162-1166
Partially purified cell wall proteinases of eight strains of Streptococcus cremoris were compared in their action on bovine αs1-, β-, and κ-casein, as visualized by starch gel electrophoresis, sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and thin-layer chromatography. Characteristic degradation profiles could be distinguished, from which the occurrence of two proteinases, represented by strain HP and strain AM1, was concluded. The action of the HP-type proteinase P1 (also detectable in strains Wg2, C13, and TR) was established by electrophoretic methods to be directed preferentially towards β-casein. The AM1-type proteinase PIII (also detectable in strain SK11) was also able to degrade β-casein, but at the same time split αs1- and κ-casein more extensively than did PI. Strain FD27 exhibited mainly PI activity but also detectable PIII degradation characteristics. The cell wall proteinase preparation of strain E8 showed low PI as well as low PIII activity. All proteinase preparations produced from κ-casein positively charged degradation products with electrophoretic mobilities similar to those of degradation products released by the action of the milk-clotting enzyme chymosin. The differences between PI and PIII in mode of action, as detected by gel electrophoresis and thin-layer chromatography, were reflected by the courses of the initial degradation of methyl-14C-labeled β-casein and by the effect of αs1- plus κ-casein on these degradations. The results are discussed in the light of previous comparative studies of cell wall proteinases in strains of S. cremoris and with respect to the growth of this organism in milk. 相似文献
4.
Pollen records of Holocene sediment cores from the Costa Rican Cordillera de Talamanca (La Chonta bog, 2310 m and La Trinidad bog, 2700 m) show the postglacial development of the montane oak forest zone from ca. 9500 to 1500 yr BP. During the early Holocene (ca. 9500–700 yr BP), alder vegetation covered the La Chonta and La Trinidad bogs and their adjacent hills. The upper forest line is inferred to be at 2800–3000 m elevation. A Podocarpus-Quercus forest characterised the middle Holocene (ca. 7000–4500 yr BP). The upper forest line is located at >3000 m reaching the present-day altitudinal distribution. A Quercus forest characterised the late Holocene (ca. 4500–1500 yr BP). Compared to modern conditions, the early Holocene has similar average temperatures, but the moisture level was probably higher. Pollen evidence for the late Holocene indicates drier environmental conditions than today. In order to improve the paleoecological interpretation, we described the local vegetation and used moss samples as pollen traps at both montane bogs along strong soil moisture gradients.The Netherlands Centre for Geo-ecological Research, ICG 相似文献
5.
Alkaline borohydride treatment is widely used for the release of carbohydrate moieties from O-glycosylated glycoproteins and mucins. We have adapted this procedure to micro quantities of glycoproteins blotted on membranes. After electrophoresis and transfer to nitrocellulose, nylon or polyvinylidene difluoride membrane, alkaline borohydride treatment was done directly on glycoprotein containing areas of membrane which were cut out with the aid of guide strips stained with Coomassie Blue or lectin-digoxigenin. In combination with standard saccharide fractionation techniques, this procedure can be used to characterize the oligosaccharides of mucins or mucin-type glycoproteins that are separated by gel electrophoresis from crude sources. Using this approach we have characterized the saccharides derived from the two species of epitectin, a malignancy-associated mucin type glycoprotein, isolated from metabolically labelled H.Ep2 cells. 相似文献
6.
P. van't Veer I. E. Lobbezoo J. M. Martín-Moreno E. Guallar J. Gómez-Aracena A. F. Kardinaal L. Kohlmeier B. C. Martin J. J. Strain M. Thamm P. van Zoonen B. A. Baumann J. K. Huttunen F. J. Kok 《BMJ (Clinical research ed.)》1997,315(7100):81-85
OBJECTIVE: To examine any possible links between exposure to DDE (1,1-dichloro-2,2-bis (p-chlorophenyl)ethylene), the persistent metabolite of the pesticide dicophane (DDT), and breast cancer. DESIGN: Multicentre study of exposure to DDE by measurement of adipose tissue aspirated from the buttocks. Laboratory measurements were conducted in a single laboratory. Additional data on risk factors for breast cancer were obtained by standard questionnaires. SETTING: Centres in Germany, the Netherlands, Northern Ireland, Switzerland, and Spain. SUBJECTS: 265 postmenopausal women with breast cancer and 341 controls matched for age and centre. MAIN OUTCOME MEASURE: Adipose DDE concentrations. RESULTS: Women with breast cancer had adipose DDE concentrations 9.2% lower than control women. No increased risk of breast cancer was found at higher concentrations. The odds ratio of breast cancer, adjusted for age and centre, for the highest versus the lowest fourth of DDE distribution was 0.73 (95% confidence interval 0.44 to 1.21) and decreased to 0.48 (0.25 to 0.95; P for trend = 0.02) after adjustment for body mass index, age at first birth, and current alcohol drinking. Adjustment for other risk factors did not materially affect these estimates. CONCLUSIONS: The lower DDE concentrations observed among the women with breast cancer may be secondary to disease inception. This study does not support the hypothesis that DDE increases risk of breast cancer in postmenopausal women in Europe. 相似文献
7.
This paper describes several technical improvements in the sucrose-plasmolyzed cell system used in earlier experiments on DNA synthesis in situ with Escherichia coli infected by DNA-defective mutants of bacteriophage T4 (W. L. Collinsworth and C. K. Mathews, J. Virol. 13:908-915, 1974). Using this system, which is based primarily on that of M. G. Wovcha et al. (Proc. Natl. Acad. Sci. U.S.A. 70:2196-2200, 1973), we reinvestigated the properties of mutants bearing lesions in genes 1, 41, and 62, and we resolved some disagreements with data reported from that laboratory. We also asked whether the DNA-delay phenotype of T4 mutants is related to possible early leakage of DNA precursors from infected cells. Such cells display defective DNA synthesis in situ, even when ample DNA precursors are made available. Thus, the lesions associated with these mutations seem to manifest themselves at the level of macromolecular metabolism. Similarly, we examined an E. coli mutant defective in its ability to support T4 production, apparently because of a lesion affecting DNA synthesis (L. Simon et al., Nature [London] 252:451-455). In the plasmolyzed cell system, reduced nucleotide incorporation is seen, indicating also that the genetic defect does not involve DNA precursor synthesis. The plasmolyzed cell system incorporates deoxynucleotide 5'-monophosphates into DNA severalfold more rapidly than the corresponding 5'-triphosphates. This is consistent with the idea that DNA precursor-synthesizing enzymes are functionally organized to shuttle substrates to their sites of utilization. 相似文献
8.
A double blind study was undertaken to determine the effectiveness or oral prostaglandin E2 as a means of improving the pelvic score prior to induction of labour. 48 patients who were greater than 37 were gestation and who had Bishop scores of less than 6 entered the study. Ten tablets were given on an hourly regime. Of 25 patients in the prostaglandin group, 17 were considered successes (68.0%), whereas of 23 patients who received a placebo, 9 were successes (39.1%). No adverse effects were recorded. Prostaglandin E2 is therefore considered a safe and effective method for priming the unfavourable cervix prior to induction of labour. 相似文献
9.
Cytochrome P-448 (mol wt 55,000 Daltons) from rabbit liver was purified to a specific content of 16.6 nmol/mg. Mice were immunised with this preparation, their spleens removed and dissociated lymphocytes hybridised with myeloma cells. Four monoclonal antibodies against cytochrome P-448 were raised and partially characterised. All four antibodies interacted with cytochrome P-448 in intact microsomal fractions and selectively immunoadsorbed cytochrome P-448 from solubilised microsomal preparations. One of the antibodies inhibited benzo[a] pyrene hydroxylase activity in a reconstituted system, one had no effect on activity and two increased activity. The possible applications of such antibodies are discussed. 相似文献
10.
Anneleen Daemen Obi L Griffith Laura M Heiser Nicholas J Wang Oana M Enache Zachary Sanborn Francois Pepin Steffen Durinck James E Korkola Malachi Griffith Joe S Hur Nam Huh Jongsuk Chung Leslie Cope Mary Jo Fackler Christopher Umbricht Saraswati Sukumar Pankaj Seth Vikas P Sukhatme Lakshmi R Jakkula Yiling Lu Gordon B Mills Raymond J Cho Eric A Collisson Laura J van’t Veer Paul T Spellman Joe W Gray 《Genome biology》2013,14(10):R110