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31.
Dr. Moyra M. McConnell Linda V. Thomas Sylvia M. Scotland Bernard Rowe 《Current microbiology》1986,14(1):51-54
A total of 134 enterotoxigenicEscherichia coli (ETEC) of serogroups O25, O27, O148, and O159 were tested in the enzyme-linked immunosorbent assays for the colonization factor antigens I (CFA/I), CFA/II (coli surface antigens CS1, 2 and 3) and putative colonization factor (PCF) 8775 (CS4, 5 and 6). CS6 was detected without CS4 or CS5 in 94% of the strains of serogroup O25, 86% of strains of serogroup O27, 87% of strains of serogroup O148, and 29% of strains of serogroup, O159. The frequency with which CS6 occurs in ETEC of common serotypes without the antigens CS4 or CS5 suggests that it might be a colonization factor. 相似文献
32.
Linda J. Van Eldik D.Martin Watterson Kam-Fook Fok Bruce W. Erickson 《Archives of biochemistry and biophysics》1983,227(2):522-533
The heptapeptide AsnTyrGluGluPheValGlnNH2 corresponding to residues 137–143 of vertebrate calmodulin is as immunoreactive as the entire 148-residue protein. A reproducible and rapid procedure for producing antisera against vertebrate calmodulin has been previously described (L. J. Van Eldik and D. M. Watterson (1981) J. Biol. Chem.256, 4205–4210). Most of the antisera elicited by this method react with a major immunoreactive region (residues 127–144) in the COOH-terminal domain of vertebrate calmodulin. In this report, the minimum segment of calmodulin required for reactivity with an antiserum that readily distinguishes various types of calmodulins is defined. These studies demonstrate that a linear segment of seven amino acid residues shows a competition curve in radioimmunoassay resembling the competition curve of intact calmodulin. This heptapeptide is the smallest calmodulin segment and the only sevenresidue segment in the 135–145 region that shows quantitative immunoreactivity with the anti-calmodulin serum. These data demonstrate that this heptapeptide is a major immunoreactive site of calmodulin. However, when this immunoreactive site heptapeptide is conjugated to a carrier and injected into rabbits, it does not elicit antisera that react with the native protein. These studies demonstrate that quantitative immunoreactivity of antisera produced in animals can be found in small peptide segments and that, for calmodulin, the requirements for production of anti-peptide antibodies that react with the native protein molecule are not as simple as surface exposure of the peptide region. 相似文献
33.
34.
Transduction and Plasmid Deoxyribonucleic Acid Analysis in a Multiply Antibiotic-Resistant Strain of Staphylococcus epidermidis 总被引:8,自引:1,他引:7 下载免费PDF全文
A genetic analysis of a multiply antibiotic-resistant strain of Staphylococcus epidermidis was performed. Experiments designed to show reversion of organisms to antibiotic susceptibility, as well as studies of the influence of ultraviolet irradiation of phage on the transduction frequencies of the resistance markers, indicated that determinants of chloramphenicol (cml), tetracycline (tet), and neomycin (neo) resistance are present on separate plasmids, but the streptomycin marker is chromosomal. In 2 to 6% of tetracycline-resistant transductants, co-transduction of cml was also observed. By using CsCl-dye density gradients followed by neutral sucrose gradients, the plasmids carrying cml, tet, and neo could be isolated and their molecular weights could be determined. The tetracycline plasmid is shown to be incompatible with one of the cryptic plasmids of a recipient strain. 相似文献
35.
Biochemical Localization of Alkaline Phosphatase in the Cell Wall of a Marine Pseudomonad 总被引:8,自引:5,他引:3 下载免费PDF全文
The various layers of the cell envelope of marine pseudomonad B-16 (ATCC 19855) have been separated from the cells and assayed directly for alkaline phosphatase activity under conditions established previously to be optimum for maintenance of the activity of the enzyme. Under conditions known to lead to the release of the contents of the periplasmic space from the cells, over 90% of the alkaline phosphatase was released into the medium. Neither the loosely bound outer layer nor the outer double-track layer (cell wall membrane) showed significant activity. A small amount of the alkaline phosphatase activity of the cells remained associated with the mureinoplasts when the outer layers of the cell wall were removed. Upon treatment of the mureinoplasts with lysozyme, some alkaline phosphatase was released into the medium and some remained with the protoplasts formed. Cells washed and suspended in 0.5 M NaCl were lysed by treatment with 2% toluene, and 95% of the alkaline phosphatase in the cells was released into the medium. Cells washed and suspended in complete salts solution (0.3 M NaCl, 0.05 M MgSO(4), and 0.01 M KCl) or 0.05 M MgSO(4) appeared intact after treatment with toluene but lost 50 and 10%, respectively, of their alkaline phosphatase. The results suggest that the presence of Mg(2+) in the cell wall is necessary to prevent disruption of the cells by toluene and may also be required to prevent the release of alkaline phosphatase by toluene when disruption of the cells by toluene does not take place. 相似文献
36.
Mary J. Kurtz Peter Polgar Linda Taylor Alexander M. Rutenburg 《The Biochemical journal》1974,142(2):339-344
Inhibition of growth and DNA synthesis was observed in WI 38 cells incubated with 8-methylthioadenosine 3':5'-cyclic monophosphate or prostaglandin E(1). The effect of both compounds on cell growth was reversible. On removal of these compounds from culture media the cells initiated DNA synthesis and divided. In addition, prostaglandin E(1) stimulated cyclic AMP formation in these cells to over 40 times the normal basal value. The increase in cyclic AMP concentration in WI 38 cells after addition of prostaglandin E(1) showed a marked variation. Cells that had recently been treated with trypsin and plated at a lower cell density exhibited a smaller response to addition of prostaglandin E(1) than cells that had divided and reached confluence. 相似文献
37.
Zusammenfassung Bei einem Patienten mit multiplen Mißbildungen wurde eine Duplikation für die distale Hälfte vom kurzen Arm des Chromosoms 2 und eine Defizienz an einem C-Chromosom gefunden. In der Literatur sind vier Fälle mit ähnlicher Duplikation, jedoch jeweils einer klein n Defizienz am Chromosom 3 beschrieben worden. Ein Vergleich der klinischen Merkmale bei den fünf Patienten zeigt weitgehende Übereinstimmungen. Es wird gefolgert, daß die gleichartige Duplikation für das einheitliche klinische Bild der Patienten verantwortlich ist. Es wurden Chromosomenmessungen, Analysen der Replikationsmuster und Meioseuntersuchungen durchgeführt. Die Genloci für das Ss- und das Rh-System konnten von einer Lokalisierung auf dem duplizierten Segment ausgeschlossen werden.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
2/C translocation in father and daughter: 46,XY t (2p-;Cp+) and 46,XX Cp+
Summary In a patient with multiple anomalies, a duplication comprising the distal half of the short arm of chromosome 2 and a small deficiency of a C-chromosome was found. Four other cases from the literature exhibit a similar duplication combined with a small deficiency each of chromosome 3. Comparison of the clinical pictures of the five patients revealed a conformity in the major features. It is concluded that the duplication is responsible for the uniform appearance of these patients. The studies performed include chromosome measurements, examination of replication patterns and meiosis. The gene loci for the Ss and Rh systems could be excluded from localization on the duplicated segment.
Mit Unterstützung durch die Deutsche Forschungsgemeinschaft. 相似文献
38.
39.
Temperature dependence of inorganic nitrogen uptake and assimilation in Antarctic sea-ice microalgae 总被引:3,自引:0,他引:3
John C. Priscu Anna C. Palmisano Linda R. Priscu Cornelius W. Sullivan 《Polar Biology》1989,9(7):443-446
Summary The influence of temperature on NO
3
-
and NH
4
+
uptake, and the activity of the assimilatory enzyme NO
3
-
reductase (NR) was compared to inorganic C uptake (photosynthesis) in natural assemblages of Antarctic sea-ice microalgae. NO
3
-
and NH
4
+
uptake reached a maximum between 0.5°–2.0°C and 2.0°–3.0°C, respectively, which was close to that for photosynthesis (2.5°–3.0°C). NR showed a distinctly higher temperature maximum (10.0°–12.0°C) and a lower Q10 value than inorganic N and C transport. Our data imply that, owing to differential temperature characteristics between N transport and N assimilation at in situ temperature (-1.9°C), the incorporation of extracellular NO
3
-
into cellular macromolecules, may be limited by transport of NO
3
-
into the cell rather than the intracellular reduction of NO
3
-
to NH
4
+
. Despite differences in temperature maxima between N transport and N assimilation, the overall low temperature maxima of inorganic N metabolism characterizes Antarctic sea-ice microalgae as psychrophilic. Our study is the first to examine the temperature dependence of inorganic N uptake and assimilation in sea-ice microbial communities. 相似文献
40.
AP-1-Related Proteins Bind to the Enkephalin CRE-2 Element in Adrenal Chromaffin Cells 总被引:1,自引:0,他引:1
Linda MacArthur 《Journal of neurochemistry》1996,67(6):2256-2264