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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The contractile sheaths of five defective, PBS X-like bacteriophages from Bacillus subtilis and B. licheniformis were investigated by electron microscopy, dodecylsulphate gel electrophoresis and immunodiffusion. Electron microscope images of the extended and contracted sheaths were of similar appearance, although their lengths were different. The surface lattices of both the extended and the contracted sheaths were determined by optical diffraction. This showed that the quaternary structure of the sheaths of all five defective phages originated from identical surface lattices, which could be approximately expressed by the selection rules L = -2n' + 3m and L = 9N' + 17M for the extended and contracted sheaths respectively, in which 6n' = n with n = 0 or an integer multiple of 6. These results indicated that the packing of the protein subunits in these sheaths differed from those of other bacteriophages, for example T4 and millimicron [Amos and Klug, J. Mol. Biol. 99, 51--73 (1975); Admiraal and Mellema, J. Ultrastruct. Res. 56, 48--64 (1976)]. The molecular weight of the main sheath protein of the defective phages, as determined by dodecylsulphate gel electrophoresis, was approximately 50000. This value differed from that for T4, but was similar to that of millimicron [Admiraal and Mellema, J. Ultrastruct. Res. 56, 48--64 (1976); King and Laemmli, J. Mol. Biol, 75, 315--337 (1973)]. The results of immunodiffusion experiments, however, pointed to a chemical difference between the sheath proteins of the defective phages and millimicron, in addition to T4.
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PMID:The quaternary structure of the sheaths of defective phages similar to PBS X. 10 70

We have isolated a new mutant of Bacillus subtilis temperature sensitive in DNA replication; its properties are those of an initiation mutant. When liquid cultures are shifted to 48 degrees DNA replication is the first macromolecular synthesis that stops, but only after synthesis of the amount of DNA predicted for the completion of one replication round. When spores of the mutant are germinated and shifted to 48 degrees at subsequent times, one round of DNA replication is observed only when the shift occurs between 60 and 100 min; earlier shifts do not allow replication to start, later shifts allow more than one replication. The DNA replicated after a shift to high temperature is enriched in markers close to the terminus. The reinitiation of DNA replication stopped by the high temperature, takes place following a shift to a permissive temperature only if protein synthesis is allowed. Examination of DNA replication following toluene treatment shows that the elongation of DNA chains is not affected at the non-permissive temperature. This mutant is shown by PBS-1 mapping to correspond to a new gene denominated dna P, which is located between the thy A and fur A genes and is distinct from all the mapped dna and rec genes of Bacillus subtilis. The mutation confers to the cells also a deficiency in the ability to be transformed, to be transfected with SPP1 phage DNA, and to survive treatment with methyl-methane sulfonate. These deficiencies, observed at the permissive temperature, are no more temperature dependent than in the parental strain. The ability to perform homologous and heterologous transduction with PBS-1 phage and the sensitivity to ultraviolet radiation or mitomycin C are normal.
Mol Gen Genet 1975
PMID:A new mutant of Bacillus subtilis altered in the initiation of chromosome replication. 81 Jun 58

This study was designed to determine what effect electropulse parameters would have on rate of fusion, lysis, and embryo viability when embryos were subjected to electrofusion treatment in nonelectrolyte or electrolyte pulse media. Previous experiments have shown electrolyte medium (i.e., phosphate-buffered saline; PBS) to have a positive effect on electric pulse-induced murine oocyte activation. In addition, these results also indicated that pulse media containing 0.9 mM Ca2+ induced a dramatic increase in the rate of murine oocyte activation compared with oocytes pulsed in media containing 0.0 or 0.05 mM Ca2+. Pronuclear or two-cell-stage embryos were obtained from superovulated prepubertal randomly bred Swiss (albino) female mice. Embryos were randomly assigned to three nonelectrolyte and three electrolyte treatment media. Nonelectrolyte media consisted of 0.3 M mannitol (T1), 0.3 M mannitol + 0.05 mM CaCl2 (T2), and 0.3 M mannitol + 0.9 mM CaCl2 (T3). Electrolyte media consisted of Ca(2+)-free PBS (T4), PBS containing 0.05 mM CaCl2 (T5), and PBS containing 0.9 mM CaCl2 (T6). Three experiments were carried out; the objective of the first was to determine the rate of fusion and rate of lysis in murine two-cell embryos placed in the two types of (0.3 M mannitol, T1-T3; and PBS, T4-T6) fusion media and subjected to a fusion procedure (3 V, 5 sec AC alignment pulse, followed by a 1.56 kV.cm-1, 99 microsec DC fusion pulse). Control two-cell embryos were placed in T1 for 2 min and did not receive a fusion pulse.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Reprod Dev 1992 Jul
PMID:Effect of electrofusion pulse in either electrolyte or nonelectrolyte fusion medium on subsequent murine embryonic development. 149 75

These experiments were designed to monitor influx of extracellular Ca2+ into the murine ooplasm following a 1.56 kV.cm-1 direct current (DC) electrofusion pulse and subsequently to determine its effect on rate of activation. Pulse media consisted of non-electrolyte (0.3 M mannitol) and electrolyte (phosphate-buffered saline; PBS) media each containing 0.0, 0.05, or 0.9 mM Ca2+ (groups T1-T3 and T4-T6, respectively). Cumulus-free oocytes were incubated in 100 microliters drops of PBS containing 2 microM of the calcium indicator fluo-3/AM for 60 min at 37 degrees C. Fluo-3/AM-loaded oocytes were equilibrated for 7 min in assigned treatment media (T1-T6) prior to application of DC pulse. Change in fluorescent intensity was monitored for 6.5 min after DC pulse by photon counting spectrofluorometry. Fluorometric measurements demonstrate a dramatic rise in intracellular free Ca2+ (Ca2+i) following DC pulse is associated with Ca2+ ion concentration in the pulse medium. Significantly (P less than 0.01) higher Ca2+i levels were observed when 0.9 mM Ca2+ was added to the pulse medium (T3 and T6) compared with pulse medium containing lower Ca2+ ion concentrations (T1, T2, T4, and T5; P greater than 0.05). Differences (P less than 0.01) were observed in peak Ca2+i levels 18 sec after pulse with mean percent change in fluorescence of 5.1%a, 33.9%b, 112.7%c, 1.2%a, 9.3%a, and 99.9%c for T1-T6, respectively (values with different superscripts are significantly different at P less than 0.01). Increased oocyte membrane permeability to Ca2+ ion after DC pulse was observed for a minimum of 5 min after delivery of the 1.56 kV.cm-1 pulse.(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Reprod Dev 1992 Feb
PMID:Electrofusion-induced intracellular Ca2+ flux and its effect on murine oocyte activation. 159 84

Rabbit zygotes and embryos were exposed to hypertonic sucrose in phosphate-buffered saline (SPBS). In experiment one, 144 zygotes shrank to 32-36% of their initial volume in 1.0 M SPBS within 30 min. Neither hypertonic treatment with 0.5 M or 1.0 M SPBS nor micropuncture of the zona pellucida after shrinkage affected embryo development into blastocysts in vitro (88%, 83%, and 82%, respectively), compared to that of the controls (93%, P greater than .05). In experiment two, 252 two- to four-cell- and 177 morula-stage embryos were exposed to isotonic PBS control or 0.5 M, 1.0 M, or 1.5 M SPBS for 30, 60, 90, 120, and 150 min before transfer to PBS (290 mOsm). Embryo development was significantly reduced (P less than .05) when embryos were exposed in 0.5 M and 1.0 M SPBS for more than 60 min or in 1.5 M SPBS for more than 30 min. In experiment 3, morulae exposed for 60 min to 0.5 M or 1.0 M SPBS shrank to 37-39% or 32-35% of their initial volume and then expanded to 87-94% or 81-90% of their initial volume, respectively, after being returned to isotonic PBS for 60 min, but embryos in 1.5 M SPBS had erratic osmotic behavior. In experiment four, 192 two- to four-cell embryos exposed to 0.5 M SPBS for 0, 30, and 60 min before transfer to oviducts of recipients resulted in the production of 39%, 42% and 31% young, respectively (P greater than .05).(ABSTRACT TRUNCATED AT 250 WORDS)
Mol Reprod Dev 1990 Oct
PMID:Potential of hypertonic medium treatment for embryo micromanipulation: I. Survival of rabbit embryos in vitro and in vivo following sucrose treatment. 224 74

The objective of this research was to study efficiency of embryo development following transfer of blastomeres into the perivitelline space of oocytes. Single blastomeres from 8-, 16-, and 32-cell embryos were obtained following mucin coat and zona pellucida removal by combined treatments with pronase and acidic phosphate-buffered saline (PBS, pH = 2.5). Blastomeres were separated by pipetting with a fire-polished micropipette following incubation in Ca+(+)-free PBS for 15 min at 39 degrees C. This procedure resulted in over 97% blastomere separation. For ease of blastomere insertion, oocytes were placed in droplets of 0.5 M sucrose in PBS (SPBS) during micromanipulation. To functionally enucleate oocytes some were stained with Hoechst 33342 DNA stain and irradiated. A single 8- or 16-cell blastomere was aspirated into an injection pipette (35 microns or 25 microns at the tip, respectively) and inserted into the perivitelline space of an irradiated or non-irradiated oocyte, but not fused with the oocyte. This micromanipulation procedure did not affect development of individual blastomeres into blastocysts or trophectoderm vesicles when compared with cultured control single blastomeres (P greater than .05). When the inserted blastomere was induced to fuse with an intact non-irradiated oocyte under an electric field, 56-57% were fused and 39-45% of the fused and activated oocytes developed to morulae or blastocysts. When an inserted blastomere (from 8-32-cell embryos) was induced to fuse with a functionally enucleated oocyte treated by Hoechst 33342 staining, followed by washing and UV-light irradiation, 63-66% of them were fused, but only 15-22% developed to the morula or blastocyst stage. This research demonstrated that the use of hypertonic medium treated oocytes greatly improved the ease and success rate of blastomere subzona insertion, but the value of functionally enucleated oocytes as recipient cells for nuclear transfer requires further investigation.
Mol Reprod Dev 1990 Oct
PMID:Potential of hypertonic medium treatment for embryo micromanipulation: II. Assessment of nuclear transplantation methodology, isolation, subzona insertion, and electrofusion of blastomeres to intact or functionally enucleated oocytes in rabbits. 224 75

Cigarette smoke has been reported to contain free radicals and free radical generators in both the gas and particulate phases. Studies in our laboratory have shown that both cigarette smoke condensate (CSC) and smoke bubbled through phosphate buffered saline solution (smoke-PBS) increased sister chromatid exchanges (SCE) in Chinese hamster ovary cells in a dose-dependent manner. Since oxygen free radicals have been shown to cause SCEs and other chromosomal damage, we investigated the role of these radicals in the induction of SCEs by CSC and smoke-PBS. Addition of the antioxidant enzymes catalase and superoxide dismutase or the oxygen-radical scavenger ascorbic acid failed to reduce the SCE frequency in the presence of either CSC or smoke-PBS. Additional studies indicated that the quantity of hydrogen peroxide produced in CSC or smoke-PBS is too small to account for the observed SCE induction. It appears, therefore, that SCE induction by CSC or smoke-PBS does not involve the participation of oxygen free radicals.
Environ Mol Mutagen 1989
PMID:Role of oxygen free radicals in the induction of sister chromatid exchanges by cigarette smoke. 264 5

Trichomonas vaginalis growing in complex medium produced volatile thiols at a rate of 0.7 nmol min-1 (mg protein)-1 and the parasite suspended in PBS with L-methionine excreted volatile thiols, including methanethiol, and alpha-keto acid. Cell-free extracts of the parasite also produced volatile thiols from L-methionine, at the rate of 5.4 nmol min-1 (mg protein)-1. Thiol production was not detectable with living cells or cell-free extracts of Tritrichomonas foetus, Trichomitus batrachorum or Pentatrichomonas hominis and homogenates of a range of trypanosomatids and mouse liver also failed to produce volatile thiols from L-methionine. Approximately equimolar concentrations of alpha-keto acid and volatile thiols were produced from L-methionine by cell-free extracts of Trichomonas vaginalis; the release of ammonia, however, was not detectable. The parasite enzyme catabolised a range of substrates and was inhibited by several compounds, including bithionol and DL-propargylglycine. Parasites grown in the presence of 10(-5) M DL-propargylglycine had no detectable L-methionine-catabolising enzyme activity. These findings indicate that T. vaginalis is significantly different from other trichomonads, a range of trypanosomatids and mouse liver in L-methionine catabolism, and that the parasite enzyme responsible for the breakdown of L-methionine in T. vaginalis appears to be similar in several ways to bacterial L-methionine-gamma-lyase (EC 4.4.1.11) and trichomonal homocysteine desulphurase (EC 4.4.1.2).
Mol Biochem Parasitol 1987 Apr
PMID:L-methionine catabolism in trichomonads. 349 35

A mutation causing an alteration in Bacillus subtilis ribosomal protein S4 was mapped by transformation and PBS-1 transduction to a site between aroG and argA, a region of the B. subtilis chromosome not previously demonstrated to contain ribosomal protein genes. The S4 mutation conferred a spore-plus phenotype in a streptomycin-resistant, spore-minus genetic background. The altered protein was detectable by polyacrylamide gel electrophoresis of ribosomal proteins of recombinants scored for the spore-plus phenotype in genetic crosses.
Mol Gen Genet 1984
PMID:Genetic mapping of a mutation causing an alteration in Bacillus subtilis ribosomal protein S4. 642 Jun 47

Interleukin-2 (IL-2) prepared from Con A-activated rat spleen cells was partially purified using hydroxylapatite chromatography (HTP) and chromatofocusing on Mono P. IL-2 eluted in a major peak between 0.1 and 0.25 M NaCl in PBS (purification factor 36-fold) and in a second peak in the high salt elution (purification factor 5-fold). When analysed on Mono P, the major peak was found to resolve into four components with apparent pI values in the range of 7.05-5.80; further activity eluted in the high salt fraction. Similar patterns were observed using high salt eluted activity with minor variations in the apparent pI values. Neuraminidase treatment caused a shift in IL-2 charge towards more basic pI values. This analysis of the multiple species of IL-2 suggests that part of the heterogeneity may be due to variation in the degree of sialylation of the peptide chain.
Mol Immunol 1984 Apr
PMID:Heterogeneity of rat TCGF defined by Mono P isoelectric focusing. 661 Jan 4


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