Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:6.2.1.7 (BAL)
 1,977 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The hydrolysis of o-nitrophenyl-beta-D-galactopyranoside (ONPG) by BAL-31, a marine Pseudomonas that acts as a host for bacteriophage PM2, was studied with intact cells and with cell-free extracts. A transport system for ONPG in whole cells and a beta-galactosidase activity in extracts were evident for cells grown on lactose minimal medium. It was found that the addition of isopropylthio-beta-D-galactopyranoside (IPTG) to cells growing in rich medium induced an ONPG hydrolytic activity detectable in cell extracts but cryptic in whole cells. The existence of a transport system for IPTG, which remained cryptic for ONPG, became apparent from studies of the rates of induction of beta-galactosidase as a function of cell mass at different concentrations of IPTG. The main properties of beta-galactosidase and the lactose transport system of BAL-31 were studied in terms of how they were affected by pH, temperature, or by the presence of several sugars. IPTG competitively inhibits the hydrolysis of ONPG by cell extracts. In cells pregrown on lactose, IPTG slightly inhibits the transport of ONPG. Glucose, and with less efficiency lactose, also inhibits the hydrolysis of ONPG in cell extracts. The growth of cells on lactose minimal medium was inhibited by the addition of IPTG. A mechanism for this inhibition and for the inhibition of ONPG transport by IPTG is discussed.
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PMID:Induction and general properties of beta-galactosidase and beta-galactoside permease in Pseudomonas BAL-31. 1 11

The lipid-containing bacteriophage PM2 can produce infectious virus in cultures infected at temperatures up to 31.5 degrees C, but not at 34 degrees C. Its host, Pseudomonas BAL-31, grows at 34 degrees C and cultures infected at that temperature undergo lysis. Sucrose-gradient analysis shows that 34 degrees C lysates contain no PM2-like particles. Temperature-shift experiments establish that the thermally sensitive process is late in infection when virus assembly is taking place. Adamantanone, a small hydrophobic molecule that perturbs membrane hydrocarbon zones, prevents the production of infective virus. Concentrations which prevent virus production have no effect on host-cell growth or stability of mature virions. Adamantanone exerts its effects late in the infectious cycle, and lysates amde in its presence contain no PM2-like particles. These experiments, carried out at 25 degrees C, indicate that adamantanone prevents the assembly of stable PM2 virus. Spin-label studies suggest that the lipid alkyl chains of the host-cell membrane are in an "ordered" state at temperatures below about 33 degrees C and undergo a transition to a "disordered" state above that temperature. Furthermore, the addition of adamantanone perturbs the hydrocarbon zones, producing a greater degree of disorder even below 25 degrees C. Our findings suggest that the cell membrane can function and grow with the lipid alkyl chains in either the "ordered" or "disordered" state, but that the "ordered" state must be maintanined for PM2 assembly to occur.
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PMID:Effect of lipid alkyl chain perturbations on the assembly of bacteriophage PM2. 16 76

An unsaturated fatty acid auxotroph, strain UFA, isolated from the marine pseudomonad Pseudomonas BAL-31, host cell of the lipid-containing bacteriophage PM2, was grown in media supplemented with different unsaturated fatty acids. Under these conditions the fatty acid composition of the cell could be altered drastically. The phase transition in the native membrane and in the extracted lipids was analyzed by electron spin resonance using a nitroxide spin probe. Membranes prepared from strain UFA grown in cis16:1 or trans16:1 showed one transition at 9.4 degrees C and 12.4 degrees C respectively. Extracted lipids in both cases had almost the same transition temperature as that of the intact membrane. Membranes prepared from Pseudomonas BAL-31 had one transition at approximately 12 degrees C, on the other hand there was no clear cut phase transition using extracted lipids. Replication of bacteriophage PM2 took place below the transition temperature of the membrane lipids in the case where strain UFA was grown in tran16:1. Other cases were not studied.
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PMID:Phase transitions in the membrane of a marine bacterium, Pseudomonas BAL-31. 17 27

We have previously characterized an extracellular nuclease from Pseudomonas BAL 31 which, in addition to other activities, displays a double-strand exonuclease activity which progressively shortens both strands of linear duplex DNA molecules from both termini. This degradation is accomplished without the introduction of detectable scissions away from the ends of the duplexes. When this nuclease is used to produce a series of progressively shortened samples from a linear duplex DNA, subsequent digestion of these samples with a site-specific restriction endonuclease and analysis of the resulting fragments by gel electrophoresis permits the rapid establishment of the order of the restriction enzyme fragments through the entire genome. This is accomplished by noting from the electropherograms the order in which the various restriction enzyme fragments become noticeably shortened or disappear. Using this method, the five cleavage sites for the endonuclease Hpa I and the single cleavage sites for the nucleases Hpa II and Pst I have been mapped in PM2 bacteriophage DNA. In a more stringent test of the method, 18 of the 24 fragments produced by cleavage of coliphage lambdab2b5c DNA with the Pst I nuclease have been mapped, and five of the six remaining fragments have been assigned to small regions of the genome.
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PMID:Extracellular nucleases of pseudomonas BAL 31. III. Use of the double-strand deoxyriboexonuclease activity as the basis of a convenient method for the mapping of fragments of DNA produced by cleavage with restriction enzymes. 30 30

The lipid-containing bacteriophage PR4 is of special intest because it can replicate in various gram-negative bacteria, including Escherichia coli, that carry one of a group of drug resistance plasmids. PR4 grown in E. coli strain PS2R contains about 10% lipid by weight, with the negatively charged phospholipid phosphatidylglycerol being the most abundant lipid in the virion. We now report the following. (i) PR4 attaches to E. coli with an attachment rate constant of Ka approximately 6.2 X 10(-10) ml/min, which is about twice that of the enveloped phage phi6 (to Pseudomonas phaseolicola), but a factor of 5 less than that of phage PM2 (to Pseudomonas BAL-31). (ii) Use of an E. coli glycerol auxotroph indicated that a normal amount of PR4 replication occurs only if glycerol starvation (inhibition of all phospholipid synthesis) begins no earlier than about halfway through the lytic cycle. (iii) Use of an E. coli fatty acid synthesis temperature-sensitive mutant and an E. coli phosphatidylethanolamine synthesis temperature-sensitive mutant indicate that PR4 replication can occur in the absence of either normal fatty acid synthesis or normal phospholipid synthesis if the infection takes place prior to the termination of overall cell growth and the onset of cell death, (iv) Whereas PR4 burst size in nutrient media at 30 degrees C to 42%C is about 40, the burst size at 20 degrees C is less than 3, Temperature-shift experiments show that the temperature late in infection determines the burst size.
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PMID:Effects of temperature and host cell genetic characteristics on the replication of the lipid-containing bacteriophage PR4 in Escherichia coli. 32 29

Turnover of the acylated and unacylated glycerol moieties of phosphatidylglycerol was examined during infection of Pseudomonas BAL-31 by bacteriophage PM2. No turnover of either glycerol moiety was observed in infected or inunfected cells. The stereochemical configuration of phosphatidylglycerol from both virus and host was determined and proved to be 3-sn-phosphatidyl-1'-sn-glycerol. These results exclude a mechanism of mobilizing lipids for the virus by acylation and deacylation of 3-sn-phosphatidyl-1'-sn-glycerol in the host membrane to form 1-sn-phosphatidyl-3'-sn-glycerol in the membrane of PM2.
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PMID:Stereoconfiguration of phosphatidylglycerol in the membrane of bacteriophage PM2 and in its host, Pseudomonas BAL-31. 63 77

In an effort to understand the genetic regulation of membrane morphogenesis, twenty-nine temperature-sensitive mutants of the membrane-containing bacteriophage PM2 were isolated. Characterization at restrictive temperature revealed groups showing no lysis (Groups I--IV), partial lysis (Groups V--VIII), and full lysis (groups IX--XII) of the host Pseudomonas BAL-31. When the cell lysis data are considered in conjunction with data on stimulation of viral DNA synthesis, at least six mutant groups are defined. Analysis by gel electrophoresis of the pattern of viral proteins synthesized under restrictive conditions further divides the mutants into twelve groups. Temperature shift experiments delineate early, intermediate and late mutants. Complementation data support some of these groupings. The observed low levels of complementation and recombination are discussed in terms of gene product/genome restriction, bound to the membrane at the site of infection. It is of particular interest to membrane morphogenesis that under restrictive conditions late mutants in Groups II, III and IV make empty-appearing vesicles inside the cell that are the size of virus membranes as seen in thin sections of cells in the electron microscope. Mutants ts 1 (Group II) and ts 12 (Group III) show defects in their ability to incorporate into membranes viral structural proteins sp 13 and sp 6.6. The possibility is discussed that either of these proteins control the size and shape of the viral membrane.
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PMID:Characterization of temperature-sensitive mutants of bacteriophage PM2: membrane mutants. 73 79

Infectious PM2 virus paticles could be reconstituted in vitro from a mixture of nucleocapsid, phospholipids containing cis fatty acids, and proteins I and II. The presence or absence of acyl phosphatidylglycerol, a minor lipid component of thevirion, did not affect the reconstitution of infectious particles, even though it was incorporated into the particles when present. When phosphatidylglycerol was completely replaced by acyl phosphatidylglycerol in the reconstitution mixture, no infections particles were formed. Lipids containing either cis or trans fatty acids were also used for reconstitution in vitro of the lipid-containing bacteriophage PM2. Regardless of the ratio of phosphatidlyglycerol to phospatidylethanolamine in the reconstitution mixture, infectious particles were formed and had almost the same phospholipid composition when lipids containing cis-palmitoleic acid were used; no infectious particles were obtained when lipids containing trans-palmitoleic acid were used. In the latter case, virus-like particles were, however, formed. Reconstituted particles containing cis fatty acids were infectious when tested on wild type Pseudomonas BAL-31 as well as on the unsaturated fatty acid auxotroph grown in the presence of either cis or trans-palmitoleic acid. Reconstituted particles containing trans fatty acids were not infectious on any of these cells. When trans fatty acids as well as cis fatty acids were present in the reconstitution mixture, then there was a lower yield of infectious particles. Particles with either cis or trans fatty acids had all four viral proteins and adsorbed to BAL-31 host cells in a specific manner.
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PMID:Structure and synthesis of a lipid-containing bacteriophage. Effects of lipids containing cis or trans fatty acids on the reconstitution of bacteriophage PM2. 84 43

Endolysin was induced in Pseudomonas BAL-31 infected with bacteriophage PM2 and was also associated with the purified virion. This enzyme required divalent cations for its activity, Ca2+ being the most effective cation. Endolysin activity in the virion increased up to three-fold upon disruption and the activity could be localized in the viral nucleocapsid. Thus the enzyme is localized within the virion. After purification of the structural proteins of bacteriophage PM2, only the nucleocapsid protein (III) had endolysin activity.
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PMID:Structure and synthesis of a lipid-containing bacteriophage. An endolysin activity associated with bacteriophage PM2. 89 52

The highly single strand-specific extracellular nuclease of Pseudomonas BAL 31 is shown to cleave non-supercoiled closed circular duplex PM2 bacteriophage DNA containing regions of altered helix structure produced in vitro by irradiation with ultraviolet light or by treatment with the carcinogen, N-acetoxy-N-2-acetylaminofluorene. Untreated samples of this DNA are affected very little by the nuclease. The unwinding of the DNA helix associated with the above treatment renders the closed circular DNA positively supercoiled compared to untreated samples. The extent of unwinding can be accurately measured and correlated with the average number of lesions per molecule of DNA by monitoring the alterations of the electrophoretic patterns, relative to those observed for untreated DNA, of such DNA in agarose gels. Interstrand cross-links and mismatched base pairs produced by treatment of non-supercoilded circular duplex DNA with the mutagen, nitrous acid, do not detectably unwind the DNA helix. The nitrous acid-treated DNA provides substrates for cleavage by the Pseudomonas nuclease which are likely to be the interstrand cross-links rather than the mismatched base pairs. Use of the Pseudomonas nuclease in conjunction with agarose gel electrophoresis can provide a powerful method for the detection of damage in duplex DNA such as that introduced by carcinogenic and mutagenic agents.
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PMID:A sensitive endonuclease probe for lesions in deoxyribonucleic acid helix structure produced by carcinogenic or mutagenic agents. 92 19


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