bluuebunny/crossref_metadata_2025 huggingface dataset:
Glycerol utilization by a mutant of Rhodopseudomonas capsulata
Authors: Lueking D , Pike L , Sojka G
Published: January 2020

The glycerol-catabolizing enzymes of a mutant of Rhodopseudomonas capsulata were found to be constitutive and modulated coordinately, although apparently not functional in the presence of malate. No difference in glycerol permeation was found between the mutant and wild type.
Effect of methionine on chemotaxis by Bacillus subtilis
Authors: Ordal G W
Published: January 2020

Bacillus subtilis, like Escherichia coli and Salmonella typhimurium, carries out chemotaxis by modulating the relative frequency of smooth swimming and tumbling. Like these enteric bacteria, methionine auxotrophs starved for methionine show an abnormally long-period of smooth swimming after addition of attractant. This "hypersensitive" state requires an hour of starvation for its genesis, which can be hastened by including alanine, a strong attractant, in starvation medium. Susceptibility to repellent, which causes transient tumbling when added, if anything, increases slightly by starvation for methionine. The results are interpreted by postulating the existence of a methionine-derived structure that hastens recovery of attractant-stimulated bacteria back to normal.
In vitro system for the synthesis of teichoic acid linked to peptidoglycan
Authors: Bracha R , Glaser L
Published: January 2020

A crude cell wall preparation from Staphylococcus aureus H prepared by the method of Mirelman and Sharon (1972) was shown to catalyze the synthesis of polyribitol phosphate linked to the cell wall peptidoglycan. The reaction used cytidine diphosphate (CDP)-ribitol as a substrate and in addition required the presence of CDP-glycerol, uridine diphosphate (UDP)-N-acetyl-D-glucosamine, and adenosine triphosphate. Incubation of radioactive CDP-glycerol with the crude cell wall preparation resulted in the transfer of glycerol phosphate residues to the cell wall; this reaction was greatly stimulated by the presence of UDP-N-acetylglucosamine. These data suggest that polyribitol phosphate is linked to the cell wall peptidoglycan by an oligomer contaning N-acetyl-D-glucosamine and glycerol phosphate.
Distribution and composition of lipopolysaccharides from mycoplasmas
Authors: Smith P F , Langworthy T A , Mayberry W R
Published: January 2020

Polymeric carbohydrates containing glycerol and fatty acids were isolated from whole cells and membranes of mycoplasmas by hot aqueous phenol extraction and gel filtration. Lipopolysaccharides were found to occur in four species of Acholeplasma, two of Anaeroplasma, and in Mycoplasma neurolyticum. None were detected in Spiroplasma citri or in five species of Mycoplasma. All lipopolysaccharides contained both neutral and N-acylated amino sugars in ratios varying from 1:1 to 3:1. The neutral sugars found in varying distribution were glucose, galactose, and mannose. The amino sugars included fucosamine, an unidentified deoxyhexosamine, galactosamine, and glucosamine. Fucosamine and glucose were the only sugars common to all lipopolysaccharides. The fatty acids were similar to those found in the lipids of each organism.
Control of inositol biosynthesis in Saccharomyces cerevisiae; inositol-phosphate synthetase mutants
Authors: Culbertson M R , Donahue T F , Henry S A
Published: January 2020

Inositol-requiring mutants of Saacharomyces cerevisiae were tested in cell extracts for the ability to convert glucose-6-phosphate to inositol-phosphate (IP synthetase) and inositol (IP phosphatase). Mutants representing any one of 10 unlinked loci conferring the inositol requirement were unable to synthesize either compound in an assay with glucose-6-phosphate as the substrate. These results indicate that the mutants lack IP synthetase activity and that at least 10 genes control the conversion of glucose-6-phosphate to inositol-phosphate. In addition, a mutation known to be unlinked with the ino1 locus interacts with a leaky ino1 allele and may play a role in the regulation of IP synthetase. This mutation causes a 47% reduction in wild-type IP synthetase activity and, when combined in a haploid strain with the leaky ino1 allele, it reduced IP synthetase activity to a level below that which is growth supporting. Wild-type and IP synthetase-deficient strains were tested for reduced nicotinamide adenine dinucleotide (NADH) accumulation, since NAD+ is required in the conversion of glucose-6-phosphate to inositol. No detectable accumulation of NADH was observed in the wild-type strain, presumably because the NADH generated is rapidly oxidized during subsequent partial reactions of IP synthetase. Mutants representing three different loci accumulate NADH and may, therefore, lack the NADH-mediated reductase activity of IP synthetase. Other mutants tested fail to accumulate NADH and may, therefore, lack the NAD+-mediated oxidase activity of IP synthetase. Phospholipid synthesis was studied by 32P pulse labeling in one mutant under conditions of inositol supplementation and starvation. Starved cells incorporate 32P into phospholipids normally for 2 h, followed by a period in which the rate of phosphatidylinositol synthesis decreases and the rate of phosphatidylcholine synthesis increases. After 5 to 6 h starvation, all cellular phospholipid synthesis ceases.
Effects of growth temperature on yield and maintenance during glucose-limited continuous culture of Escherichia coli
Authors: Mainzer S E , Hempfling W P
Published: January 2020

The effects of growth temperature on the aerobic growth yield with respect to oxygen consumption (Y0-grams [dry weight] per gram-atom of O) and the rate of maintenance respiration (m0-milligram-atoms of O/gram [dry weight] per hour) are reported for Escherichia coli B cultivated continuously in the presence of oxygen with limiting glucose. During anaerobic continuous culture, YATP(max) (grams [dry weight] per mole of ATP corrected for maintenance) increases from 10.3 to 12.7 as the growth temperature is lowered from 37 to 25 C. Over this same range, Y0(max) (Y0 corrected for maintenance respiration) rises from 12.5 to 28.8 and remains at the higher value down to 17.5 C. From 37 to 32 C, m0 increases from 0.9 to 4.4 but then falls to 1.5 as the temperature is lowered to 17.5 C. The value of m0 sharply rises some 13-fold as the temperature is raised to 42 C without a significant change in the value of Y0(max). Changes of Y0(max) are consistent with a temperature-sensitive doubling of the efficiency of oxidative phosphorylation, but the reasons for the changes of the rate of maintenance respiration are not known.
Genetics and complementation of Haemophilus influenzae mutants deficient in adenosine 5'-triphosphate-dependent nuclease
Authors: Kooistra J , Small G D , Setlow J K , Shapanka R
Published: January 2020

Eight different mutations in Haemophilus influenzae leading to deficiency in adenosine 5'-triphosphate (ATP)-dependent nuclease have been investigated in strains in which the mutations of the originally mutagenized strains have been transferred into the wild type. Sensitivity to mitomycin C and deoxycholate and complementation between extracts and deoxyribonucleic acid (DNA)-dependent ATPase activity have been measured. Genetic crosses have provided information on the relative position of the mutations on the genome. There are three complementation groups, corresponding to three genetic groups. The strains most sensitive to mitomycin and deoxycholate, derived from mutants originally selected on the basis of sensitivity to mitomycin C or methyl methanesulfonate, are in one group. Apparently all these sensitive strains lack DNA-dependent ATPase activity, as does a strain intermediate in sensitivity to deoxycholate, which is the sole representative of another group. There are four strains that are relatively resistant to deoxycholate and mitomycin C, and all of these contain the ATPase activity. Three of these are in the same genetic and complementation group, whereas the other incongruously belongs in the same group as the sensitive strains. It is postulated that there are three cistrons in H. influenzae that code for the three known subunits of the ATP-dependent nuclease.
Relationship of structure to function in bacterial endotoxins. IX. Differences in the lipid moiety of endotoxic glycolipids
Authors: Ng A K , Butler R C , Chen C L , Nowotny A
Published: January 2020

Chemical, immunochemical, chromatographic, and endotoxic properties of five chromatographically pure glycolipids were compared. The preparations were extracted by chloroform-methanol from three Escherichia coli, one Salmonella minnesota, and one S. typhimurium Re heptoseless mutant strains. The local Shwartzman skin assay, the nonspecific resistance-enhancing effect, and the Limulus assays could not distinguish among the five glycolipids, all five being active in all three assays. Significant differences could be seen when the tumor resistance-enhancing effect of the glycolipids in mice was compared with the nonspecific TA3-Ha murine mammary adenocarcinoma growing in ascites form. Even greater variation was observed in the capacity of the preparations to enhance the nonspecific resistance of mice to virulent S. typhi 0901 infections. The data show that the five glycolipids are quite dissimilar in their biological effects. Similarly, thin-layer chromatography and molecular ratio determinations showed that differences exist in the chemical structure of the glycolipids. Accordingly, we claim that not only the polysaccharide but the lipid moiety as well may vary in various gram-negative endotoxin preparations.
Effect of colicin K on a membrane-associated, energy-linked function
Authors: Sabet S F
Published: January 2020

The purpose of this work was in investigate the capability of cell extracts of Escherichia coli and E. coli treated with colicin K to catalyze the following energy-dependent reverse transhydrogenase reaction: NADP + NADH + ATP in equilibrium NADPH + NAD +ADP + Pi. Under anaerobic conditions this reaction requires the presence of a specific portion of the electron transport chain, a functional energy coupling system, including an adenosine triphosphatase, enzyme, and ATP as energy source. The ATP-linked reaction was partially inhibited in French press extracts of E. coli K-12 C600 cells that had been pretreated with colicin K but not in extracts from similarly treated cells of a colicin-tolerant mutant. Ultracentrifugation of extracts yielded particulate fractions competent in catalyzing the reaction; this reaction is substantially inhibited in fractions from colicin-treated cells. The extent of inhibition increased with increasing concentration of colicin. Supernatants also supported ATP-linked formation of NADPH, but this reaction was insensitive to the colicin effect. A comparison between the requirement of the reaction in supernatant and particulate fractions suggests that the reaction in the supernatant is different from the one inhibited by colicin. The ATP-hydrolyzing ability of particulate fractions from the control or treated bacteria was identical. Likewise, the electron transport chain was not affected by colicin treatment, as evidenced from lack of effect on NADH oxidase, succinic dehydrogenase, and NADPH-NAD transhydrogenase. It is concluded that colicin K interferes with the coupling of ATP the utilization of the intermediate for the ATP-linked transdehydrogenase reaction.
Purification and properties of chorismate mutase-prephenate dehydratase and prephenate dehydrogenase from Alcaligenes eutrophus
Authors: Friedrich B , Friedrich C G , Schlegel H G
Published: January 2020

Chorismate mutase and prephenate dehydratase from Alcaligenes autophus H16 were purified 470-fold with a yield of 24%. During the course of purification, including chromatography on diethylaminoethyl (DEAE)-cellulose, phenylalanine-substituted Sepharose, Sephadex G-200 and hydrogyapatite, both enzymes appeared in association. The ratio of their specific activities remained almost constant. The molecular weight of chorismate mutase-prephenast dehydratase varied from 144,000 to 187,000 due to the three different determination methods used. Treatment of electrophoretically homogeneous mutase-dehydratase with sodium dodecyl sulfate dissociated the enzyme into a single component of molecular weight 47,000, indicating a tetramer of identical subunits. The isoelectric point of the bifunctional enzyme was 5.8. Prephenate dehydrogenase was not associated with other enzyme activities; it was separated from mutasedehydratase by DEAE-cellulose chromatgraphy. Chromatography on DEAE Sephadex, Sephadex G-200, and hydroxyapatite resulted in a 740-fold purification with a yield of 10%. The molecular weight of the enzyme was 55,000 as determined by sucrose gradient centrifugation and 65,000 as determined by gel filtration or electrophoresis. Its isoelectric point was pH 6.6. In the overall conversion of chorismate to phenylpyruvate, free prephenate was formed which accumulated in the reaction mixture. The dissociation of prephenate allowed prephenate dehydrogenase to compete with prephenate dehydratase for the substrate.
Relationship between cortex content and properties of Bacillus sphaericus spores
Authors: Imae Y , Strominger J L
Published: January 2020

The muramic lactam content of spores of Bacillus sphaericus mutants defective in meso-diaminopimelic acid synthesis increases almost linearly with an increase of meso-diaminopimelic acid concentration in the medium. Since muramic lactam content is a measure of cortex content, the amount of cortex in spores of the mutants can be easily varied by changing the meso-diaminopimelic acid concentration in the medium. Characteristic properties were tested in spores containing different amounts of cortex. Critical amounts of cortex were associated with different spore properties. Refractility and dipicolinic acid accumulation in the spores both required about 20% of the maximum cortex content (although refractility is independent of dipicolinic acid content). For xylene octanol resistance, about 25% of the maximum cortex content was required.
Development of Microbodies in the yeast Kloeckera growing on methanol
Authors: Tanaka A , Yasuhara S , Kawamoto S , Fukui S , Osumi M
Published: January 2020

A number of microbodies appear regularly in methanol-grown yeast cells, but rarely in ethanol- or glucose-grown cells. When one of representative methanol-utilizing yeasts, Kloeckera sp.no. 2201 (also known as Candida bodinii), was cultured on glucose and then transferred into a methanol medium, microbodies of small size could be observed in 2-h old cells. The number of microbodies per sectioned cell reached five to six after 4 h of cultivation. Though the number of microbodies did not change during prolonged cultivation, their size became larger with the passage of cultivation time. The activities of catalase and alcohol oxidase were confirmed in the particulate fractions throughout the cultivation period, whereas the activities of formaldehyde dehydrogenase and formate dehydrogenase were not detected in the particles. The activity of isocitrate lyase was detected in the particulate fractions only at the early growth phase.
Calcium-requiring step in the uptake of deoxyribonucleic acid molecules through the surface of competent pneumococci
Authors: Seto H , Tomasz A
Published: January 2020

The conversion of surface-adsorbed deoxyribonucleic acid (DNA) molecules to a state in which they are inaccessible to exogenous deoxyribonuclease requires specifically calcium ions; magnesium ions cannot replace calcium ions. Virtually maximal levels of nuclease-resistant DNA binding and genetic transformation can be obtained in media free from magnesium and containing only calcium ions. It is suggested that the calcium-requiring process is the transport of DNA molecules across the plasma membrane. Magnesium ions stimulate both the loss of surface-adsorbed DNA to the medium and the extracellular degradation of DNA.
Escherichia coli mutants deficient in guanine-xanthine phosphoribosyltransferase
Authors: Holden J A , Harriman P D , Wall J D
Published: January 2020

We studied the purine phosphoribosyltransferases (PRTases) of Escherichia coli and were able to isolate a mutant that is defective in its ability to convert guanine and xanthine to their respective ribonucleotides. The affected gene (gpt) lies between metD and proA and is 78.6% co-transducible with proA. Both this point mutant and a strain with a pro-lac deletion contain less than 2% of wild-type xanthine PRTase activity, yet still contain about 30% of wild-type guanine PRTase activity. Thus, the gpt gene is only one of at least two genes responsible for guanine PRTase activity in E. coli.
Magnitude of the protonmotive force in respiring Staphylococcus aureus and Escherichia coli
Authors: Collins S H , Hamilton W A
Published: January 2020

The membrane potential and pH gradient developed across the plasma membranes of whole cells of Staphylococcus aureus and spheroplasts of Escherichia coli were estimated. The distributions of potassium ions in the presence of valinomycin and the pH gradient across the membrane were determined from the changes in pK and pH observed in the external medium during transition from the energized respiring state to the de-engerized resting condition. The protonmotive force in respiring cells was estimated at 211 mV for S. aureus and 230 mV for E. coli at external pH values of approximately 6.5. The adequacy of these protonmotive forces as a driving force for substrate accumulation or adenosine 5'-triphosphate synthesis is discussed.
Role of L-threonine dehydrogenase in the catabolism of threonine and synthesis of glycine by Escherichia coli
Authors: Newman E B , Kapoor V , Potter R
Published: January 2020

The enzyme L-threonine dehydrogenase was demonstrated in extracts of Escherichia coli K-12, and was shown to be the first enzyme of the pathway converting threonine to glycine. The enzyme was induced by L-leucine, but not by its substrate, L-threonine. The metabolic significance of leucine as a catabolic signal for amino acid degradation is considered.
Membranes of Rhodospirillum rubrum: physicochemical properties of chromatophore fractions isolated from osmotically and mechanically disrupted cells
Authors: Collins M L , Niederman R A
Published: January 2020

Isolation of highly purified membrane fractions from phototrophically grown Rhodospirillum rubrum was achieved by velocity and isopyknic sedimentation under carefully controlled ionic conditions. Bacteriochlorophyll-rich and succinic dehydrogenase-rich chromatophores that were essentially devoid of contamination by non-chromatophore protein were separated from a denser fraction in extracts disrupted in a French pressure cell. Highly purified chromatophores and a nearly photopigment-free envelope fraction were also obtained from cells lysed by treatment with ethylenediaminetetraacetate-lysozyme-Brij 58. After lysis with lysozyme and ethylenediaminetetraacetate alone, about 50% of the total photosynthetic pigment was released in chromatophores similar to those isolated by the above procedures. Chromatophores prepared by each method were found to have very similar near-infrared absorption spectra, overall chemical composition, equilibrium buoyant densities in CsCl, and protein patterns in sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The protein profiles of the dense, outer membrane-rich fractions were different from those of the chromatophores. The release of much of the photosynthetic apparatus as discrete chromatophores is osmotically lysed extracts necessitates a reevaluation of the concept that isolated chromatophores arise only from mechanical comminution of a larger membrane structure.
Metabolism of the reserve polysaccharide of Streptococcus mitior (mitis): is there a second alpha-1,4-glucan phosphorylase?
Authors: Pulkownik A , Walker G J
Published: January 2020

The alpha-1,4-glucan phosphorylase (alpha-1,4-glucan: orthophosphate glucosyltransferase; EC 2.4.1.1) associated with the particulate cell fraction of Streptococcus mitior strain S3 was compared with the soluble maltodextrin phosphorylase that had been previously isolated from the same organism (Walker et al., 1969). The particulate enzyme was more sensitive to the glycogen content of the cell than the soluble euzyme; its activity was highest when the cells were grown under conditions favoring high glycogen storage. Substrate specificities of the two high activity towards endogenous glycogen, whereas low-molecular-weight maltodextrins were the preferred substrates for the soluble phosphorylase. The purification of the particulate phosphorylase included incubation of the particulate fraction in 160 mM sodium phosphate-10 mM sodium citrate-0.1% (wt/vol) Triton X-100 buffer (pH 6.7) and ion-exchange chromatography on diethylamino-ethyl- Sephadex A-50. The purified enzyme was fully soluble. The value for the purification factor was variable and depended on (i) the substrate used and (ii) whether the synthetic or the degradative reaction was being measured. The solubilization resulted in considerable changes in the properties of the phosphorylase: the pH optimum for activity was raised from 6.0 to 7.0-7.5 and the substrate specificity was altered. Consequently, the purified enzyme bore greater similarity to the soluble maltodextrin phosphorylase. The reported results are best explained in terms of a single phosphorylase, the specificity which is determind by its binding state in the cell. The enzyme acts as a glycogen phosphorylase in the particulate state and as a maltodextrin phosphorylase when soluble. The equilibrium between the two forms is related to the glycogen content of the cells.
Amidase activity involved in peptidoglycan biosynthesis in membranes of Micrococcus luteus (sodonensis)
Authors: Jensen S E , Campbell J N
Published: January 2020

Membrane suspensions prepared from Micrococcus luteus (sodonensis) in both the exponential and stationary phases of growth contained a transglycosidase activity capable of synthesizing linear peptidoglycan. Exponential-phase membranes also contained an N-acetylmuramyl-L-alanine amidase activity which degraded the peptidoglycan as it was formed. The product of this amidase was purified and found to be free pentapeptide. The amidase was specific for peptidoglycan and could not attack lower-molecular-weight substrates even though the susceptible bond was present. Crude cell wall preparations isolated from exponential-phase cells also contained high levels of amidase. This cell wall-bound amidase would preferentially degrade in vitro-synthesized peptidoglycan over its own cell wall. Amidase activity could be solubilized from both cell walls and membranes by Triton X-100 treatment, butanol extraction, or LiCl extraction. Both membrane- and cell wall-derived amidases, solubilized by LiCl extraction, appeared to be of high molecular weight (greater than 150,000). Once solubilized, these wall- and membrane-derived amidases could attack the cross-bridged peptidoglycan of purified native cell walls, whereas bound amidases could not.
Isolation and characterization of T-even ghost-tolerant mutants of Escherichia coli
Authors: Nishikawa Y , Maruo B
Published: January 2020

Mutants of Escherichia coli tolerant to the ghosts of T-even phages (T2, T4, and T6) have been isolated from a strain supersensitive to T6 phage. First, T6 supersensitive mutants were isolated from mutagenized E. coli W2252 by replica plating to T6 phage-overlaid agar. One of them, strain NM101, was mutagenized again, grown, and then plated with a high multiplicity of T4 and T6 ghosts. Surviving cells were checked for tolerance to ghosts and adsorption of phages. One such ghost-tolerant mutant, strain GT29, was tolerant to ghosts of both T4 and T6 phages and sensitive to T2 ghosts. This mutant was also sensitive to ethylenediaminetetraacetic acid and penicillin G and intermediately sensitive to acriflavine, sodium dodecyl sulfate, sodium deoxycholate, actinomycin D, and lysozyme. Another mutant, strain GT62, was tolerant not only to T4 and T6 ghosts but also to T2 ghosts. It was sensitive to sodium dodecyl sulfate, sodium deoxycholate, penicillin G, acridine orange, actinomycin D, phenethyl alcohol, and novobiocin and intermediately sensitive to acriflavine and lysozyme. Spontaneous revertants of strain GT62 were isolated with a frequency of 2.7 X 10(-9). It is suggested that ghosts attack host bacteria indirectly through the cell surface by a mechanism similar to the transmission hypothesis that was originally adopted by Nomura (1967) to explain the mechanism of the action of colicins, and that our ghost-tolerant mutants presumably have defects in the cell surface.
Catechol 1,2-dioxygenase from Acinetobacter calcoaceticus: purification and properties
Authors: Patel R N , Hou C T , Felix A , Lillard M O
Published: January 2020

Procedures for the purification of catechol 1,2-dioxygenase from extracts of Acinetobacter calcoaceticus strain ADP-96 are described. The purified enzyme was homogeneous as judged by ultracentrifugation and acrylamide gel electrophoresis. The enzyme contained 2 g-atoms of iron per mol of protein. The enzyme had a broad substrate specificity and catalyzed the oxidation of catechol, 4-methylcatechol, 3-methylcatechol, and 3-isopropyl catechol. The activity of the enzyme was inhibited by heavy metals, sulfhydryl inhibitors, and substrate analogues. The molecular weight of the enzyme was 85,000 as estimated by filtration on Bio-Gel agarose and 81,000 as estimated by sedimentation equilibrium analysis. The subunit size determined by sodium dodecyl sulfate-gel electrophoresis was 40,000. The amino terminal amino acid was methionine. The amino acid composition and spectral properties of 1,2-dioxygenase are also presented. Antisera prepared against the purified enzyme cross-reacted and inhibited enzyme activity in crude extracts from the other strain of A. calcoaceticus, but failed to cross-react and inhibit isofunctional enzyme from organisms of the genera Pseudomonas, Alcaligenes, and Nocardia.
Isolation, by tetracycline selection, of small plasmids derived from R-factor R12 in Escherichia coli K-12
Authors: Mickel S , Bauer W
Published: January 2020

The examination, by agarose gel electrophoresis, of tetracycline-resistant colonies of Escherichia coli K-12 carrying R-factor R12 reveals the presence of smaller plasmid deoxyribonucleic acids (DNAs), incompatible with R12, in many of the clones. These plasmids are demonstrated to be homologous with R12 DNA by electron microscope heteroduplex experiments and by the production of consistent fragment patterns upon digestion with various restriction endonucleases. These autonomously replicating plasmids form a related series of covalently closed circular DNA molecules ranging in size from 3.6 X 10(6) to 61 X 10(6) daltons. Plasmids of molecular weight between 3.6 X 10(6) and 37 X 10(6) confer no antibiotic resistances, but when jointly present with R12 by nonetheless enhance the expression of the tetracycline resistance associated with this latter molecule.
Outgrowth of
Bacillus megaterium
Spores in the Presence of Nitrate and Ammonium Ions
Authors: Feeherry Florence E. , Levinson Hillel S.
Published: January 2020

Nitrate or ammonium ions, but not nitrite ion, supplied the nitrogen required for outgrowth of
Bacillus megaterium
QM B1551 spores through the first cell division. This outgrowth was markedly favored by K
+
.
Genetic control of the glp system in Bacillus subtilis
Authors: Lindgren V , Rutberg L
Published: January 2020

In pleiotropic negative glycerol utilization mutants (GlpPI mutants) of Bacillus subitilis, glycerol kinase and sn-glycerol 3-phosphate (G3P) dehydrogenase are noninducible. GlpPI mutants also fail to take up exogenous [14C]G3P. To study the regulation of the glp system in B. subtilis phenotypically, Glp+ revertants were isolated from GlpPI mutants. Four classes of revertants were identified: phenotypically, wild type; R1 type, which contains an informational suppressor, R2 type, which produced G3P dehydrogenase constitutively; and R3 type, with a temperature-sensitive Glp phenotype producing G3P dehydrogenase constitutively at permissive temperature (32 degrees C). The properties of the revertants indicate that the glpPI locus codes for a protein with a positive regulatory function.
Membrane-bound respiratory of Spirillum itersonii
Authors: Dailey H A
Published: January 2020

The membrane-bound respiratory system of the gram-negative bacterium Spirillum itersonii was investigated. It contains cytochromes b (558), c (550), and o (558) and beta-dihydro-nicotinamide adenine dinucleotide (NADH) and succinate oxidase activities under all growth conditions. It is also capable of producing D-lactate and alpha-glycerophosphate dehydrogenases when grown with lactate or glycerol as sole carbon source. Membrane-bound malate dehydrogenase was not detectable under any conditions, although there is high activity of soluble nicotinamide adenine dinucleotide: malate dehydrogenase. When grown with oxygen as the sole terminal electron acceptor, approximately 60% of the total b-type cytochrome is present as cytochrome o, whereas only 40% is present as cytochrome o in cells grown with nitrate in the presence of oxygen. Both NADH and succinate oxidase are inhibited by azide, cyanide, antimycin A, and 2-n-heptyl-4-hydroxyquinoline-N-oxidase at low concentrations. The ability of these inhibitors to completely inhibit oxidase activity at low concentrations and their effects upon the aerobic steady-state reduction levels of b- and c-type cytochromes as well as the aerobic steady-state reduction levels obtained with NADH, succinate, and ascorbate-dichlorophenolindophenol suggest that presence of an unbranched respiratory chain in S. itersonii with the order ubiquinone leads to b leads to c leads to c leads to oxygen.
Localization of ampicillin-sensitive sites in Escherichia coli by electron microscopy
Authors: Staugaard P , van den Berg F M , Woldringh C L , Nanninga N
Published: January 2020

Growth of Escherichia coli B/r ATCC 12407 (doubling time, 65 to 70 min) in the presence of 500 mug of ampicillin per ml for 15 to 20 min induces a sphere alongside the cell. The position was determined with respect to the length axis of the cell by electron microscopy. Although spheres may be found anywhere, some prominent sites do occur. In the shortest cells, which have a length of about 1.5 mum, they are found at the presumed new cell pole. In slightly older cells (length, about 1.8 mum), the position of the sphere is not well defined. Later on spheres occur predominantly at the cell center. In dividing cells (average length, 2.5 mum) a sphere may also occur at about one-quarter of the cell length. The position of the spheres bears resemblance to sites where a pulse of 3H-labeled diaminopimelic acid is incorporated into the peptidoglycan, as has been found by others.
Missense mutations in the lacZ gene that result in degradation of beta-galactosidase structural protein
Authors: Zipser D , Bhavsar P
Published: January 2020

Thirty-two missenese mutations were found among more than 200 independently induced mutations in the lacZ gene of Escherichia coli. Twenty of these missense mutations were induced by nitrosguandine, and 12 were induced by aminopurine. The lacZ structural protein was endogenously degradable in seven of the mutant strains; the mutations in these strains were found to lie at only three sites in the lacZ gene. Five of the seven independent mutations were at a single site, and some heterogeneity in the degradation of the lacZ protein was observed within these mutant strains.
Independence of deoxyribonucleic acid replication and initiation from membrane fluidity and the supply of unsaturated fatty acids in Escherichia coli
Authors: Thilo L , Vielmetter W
Published: January 2020

Mutant derivatives of the unsaturated fatty acid auxotroph K1062 were employed to investigate whether the supposedly membrane-bound bacterial replication machinery requires for its replicatory functions a fluid membrane environment as is known for several membrane-associated protein functions. Temperatures Tt for fluid reversible nonfluid phase transitions of membrane phospholipids are raised from below 18 to 38 degrees C when mutant cells are supplemented with elaidate instead of with oleate. In this experimental system current or synchroneously initiated new rounds of DNA replication are shown in vivo to continue 8 degrees below Tt, provided appropriate corrections for the concurrent cellular metabolic breakdown are considered. Temperature rate profiles for in vitro deoxyribonucleic acid replication rates measured in lysates of either oleate- or elaidate-supplemented cells yield congruent Arrhenius plots without discontinuities at corresponding Tt positions. We conclude that neither the start nor the propagation of replication forks depends on a fluid membrane. The capacity for the assembly of new replication complexes was studied in replication-aligned cells either shifted from oleate to elaidate (at temperatures below Tt for newly synthesized phospholipids) or starved for oleate. Regardless of whether unsaturated fatty acids are exchanged or completely withheld, new replication complexes can be normally assembled and initiated. These results do not support the conclusions reached by Fralick and Lark (1973) that the availability of unsaturated fatty acids is a prerequisite for the assembly of a functional replication complex.
Septum formation-defective mutant of Escherichia coli
Authors: Normark S , Norlander L , Grundström T , Bloom G D , Boquet P , Frelat G
Published: January 2020

Mutants of Escherichia coli defective in septum initiation, as well as in septum formation were obtained spontaneously, without mutagenic treatment, by selection of rifampin-tolerant mutants of an antibiotic-permeable strain carrying the envA mutation. The disturbed phenotype was in all mutants aggrevated the low incubation temperatures. One allele, sefA1, was studied in detail. Septum initiation, as well as septum formation, was promoted by high cell densities or by the addition of low concentrations of certain antibiotics, e.g., rifampin and chloramphenicol, to low-density cultures. The observed rifampicin depencence was studied in detail. These experiments indicated that a very modest shift-down situation suppressed the phenotype and enabled constrictions to proceed to cell separation. The rifampicin sensitivity of the partially purified deoxyribonucleic acid polymerase was not affected by the sefA1 allele, which is located close to proA and is thus distinct from envA. Growth parameters during the shift to 25 degrees C were followed in a transductant carrying HE SEFA1 allele. This constriction was characteristically blunt and did not lead to cell separation. At the time of formation of these frozen constrictions, clear zones representing a separation of wall from cytoplasmic membrane appeared. These polar tips did not inhibit expansion of the cell envelope. The phenotype of cells carrying the sefA1 allele suggests a disturbed relationship among protoplasm expansion, envelope growth, and septum formation. It is thought that the blunt constrictions observed are caused by an inability of the two septal peptidoglycan layers to fuse during an early stage of septation.
Rate of Synthesis of Polyadenylate-Containing Ribonucleic Acid During the Yeast Cell Cycle
Authors: Hynes Nancy E. , Phillips Stephen L.
Published: January 2020

The rate of synthesis of polyadenylate-containing ribonucleic acid is constant throughout the cell cycle of
Saccharomyces cerevisiae
.
Enzyme secretion in Escherichia coli: synthesis of alkaline phosphatase and acid hexose phosphatase in the absence of phospholipid synthesis
Authors: Beacham I R , Taylor N S , Youell M
Published: January 2020

De novo synthesis of two periplasmic enzymes in Escherichia coli, alkaline phosphatase and acid hexose phosphatase, have been studied in the presence and absence of new phospholipid synthesis. Alkaline phosphatase synthesis was initiated by a temperature shift in a strain carrying a phoA amber mutation and a temperature-sensitive suppressor mutation; acid hexose phosphatase was studied after relief of catabolite repression. Glycerol auxotrophs (gpsA) were used to control phospholipid synthesis. Synthesis of both enzymes proceeded at a normal rate for 0.5 to 1.0 generation of growth, although it was then curtailed. It is concluded that secretion of these enzymes is not obligatorily coupled to new net phospholipid synthesis.
Isolation of dicarboxylic acid- and glucose-binding proteins from Pseudomonas aeruginosa
Authors: Stinson M W , Cohen M A , Merrick J M
Published: January 2020

Inducible binding proteins for C4-dicarboxylic acids (DBP) and glucose (GBP) were isolated from Pseudomonas aeruginosa by extraction of exponential-phase cells with 0.2 M MgC12 (pH 8.5) and by an osmotic shock procedure without affecting cell viability. DBP synthesis was induced by growth on aspartate, alpha-ketoglutarate, succinate, fumarate, malate, and malonate but not by growth on acetate, citrate, pyruvate, or glucose. Binding of succinate by DBP was competitively inhibited by 10-fold concentrations of fumarate and malate but not by a variety of related substances. GBP synthesis and transport of methyl alpha-glucoside by whole cells were induced by growth on glucose or pyruvate plus galactose, 2-deoxyglucose, or methyl alpha-glucoside but not by growth on gluconate, succinate, acetate, or pyruvate. The binding of radioactive glucose by GBP was significantly inhibited by 10-fold concentrations of glucose, galactose, and glucose-1-phosphate but not by the other carbohydrates tested. The binding of glucose by GBP or succinate by DBP did not result in any chemical alteration of the substrates.
TolF locus in Escherichia coli: chromosomal location and relationship to loci cmlB and tolD
Authors: Foulds J
Published: January 2020

The tentative map position on the Escherichia coli chromosome of the tolF locus, determining tolerance to colicins A, E2, E3, K, and L, has been confirmed by three-point transduction. It lies between the aroA and pyrD loci at about 21 min on the linkage map of Bachmann et al. (1976). The cmlB locus, determining increased resistance to the antibiotics chloramphenicol and tetracycline, also lies in this region (Reeve, 1966). Phenotypic and genetic comparison of isogenic strains that carry a mutation in either the tolF or cmlB locus makes it likely that these loci are closely related or identical. The tolD locus determining tolerance to colicins E2 and E3 as well as increased resistance to antibiotics has been reported to be located close to the aroA locus as a result of conjugation experiments (Eriksson-Grennberg et al. 1965). However, tolD did not cotransduce with any of several loci in this region, indicating that the mutation is not located within the region of the genetic map corresponding to approximately 19 to 22.5 min.
Bacterial cis-dihydrodiol dehydrogenases: comparison of physicochemical and immunological protperties
Authors: Patel T R , Gibson D T
Published: January 2020

Cells of Pseudomonas putida NP, Pseudomonas species (NCIB 9816), and a Nocardia species, after growth on naphthalene as sole source of carbon and energy, contain a nicotinamide adenine dinucleotide (NAD+)-dependent enzyme that oxidizes cis-dihydrodiols of mono- and polycyclic aromatic compounds. Similarly, cells of a strain of P. putida biotype A, when grown either on toluene or benzene vapors, were found to contain a dehydrogenase that oxidized dihydrodiols of aromatic hydrocarbons with cis stereochemistry and required NAD+ as an electron acceptor. In all these cases, no enzymatic activity was detected when trans-naphthalene dihydrodiol was used as a substrate. Purified cis-naphthalene dihydrodiol dehydrogenase was injected into rabbits to obtain antibodies. Physiocochemical and immunological properties of cis-dihydrodiol:NAD+ oxidoreductases from four different organisms were examined. Kinetic analysis showed that, in all the cases, enzymes exhibited higher affinity for cis-dihydrodiols than for NAD+ and had pH optima between 8.8 and 9.0. except in the case of the enzyme from Nocarida sp., which showed maximum activity at pH 8.4. Molecular-weight determination of the dehydrogenases from the four different organisms by gel filtration on a Sephadex G-200 column gave values ranging from 92,000 for the enzyme from Nocardia sp. to 160,000 for that from P. putida biotype A. All the dehydrogenases, except the one from Nocardia sp., exhibited immunological cross-reaction with the antibodies prepared against the enzyme purified from P. putida NP.
Purification and characterization of cytochrome c3, ferredoxin, and rubredoxin isolated from Desulfovibrio desulfuricans Norway
Authors: Bruschi M , Hatchikian C E , Golovleva L A , Gall J L
Published: January 2020

Different electron carriers of the non-desulfoviridin-containing, sulfate-reducing bacterium Desulfovibrio desulfuricans (Norway strain) have been studied. Two nonheme iron proteins, ferredoxin and rubredoxin, have been purified. This ferredoxin contains four atoms of non-heme iron and acid-labile sulfur and six residues of cysteine per molecule. Its amino acid composition suggests that it is homologous with the other Desulfovibrio ferredoxins. The rubredoxin is also an acidic protein of 6,000 molecular weight and contains one atom of iron and four cysteine residues per molecule. The amino acid composition and molecular weight of the cytochrome c3 from D. desulfuricans (strain Norway 4) are reported. Its spectral properties are very similar to those of the other cytochromes c3 (molecular weight, 13,000) of Desulfovibrio and show that it contains four hemes per molecule. This cytochrome has a very low redox potential and acts as a carrier in the coupling of hydrogenase and thiosulfate reductase in extracts of Desulfovibrio gigas and Desulfovibrio desulfuricans (Norway strain) in contrast to D. gigas cytochrome c3 (molecular weight, 13,000). A comparison of the activities of the cytochrome c3 (molecular weight, 13,000) of D. gigas and that of D. desulfuricans in this reaction suggests that these homologous proteins can have different specificity in the electron transfer chain of these bacteria.
Two polypeptides associated with the ribonucleic acid polymerase core of Bacillus subtilis during sporulation
Authors: Fukuda R , Doi R H
Published: January 2020

The ribonucleic acid (RNA) polymerase from log-phase and sporulating cells of Bacillus subtilis was analyzed to determine whether any structural changes occurred during sporulation. The elution pattern of RNA polymerase from a deoxyribonucleic acid (DNA)-cellulose column revealed that sporulating cells at stages III and IV contained a new RNA polymerase fraction in addition to the vegetative holoenzyme (alpha2betabeta'sigma). Stage III cells contained the vegetative holoenzyme and a new enzyme with the composition alpha2betabeta'delta1; the molecular weight of delta1 was 28,000. Stage IV cells contained the vegetative holoenzyme, the delta1-containing enzyme, and another enzyme with the composition alpha2betabeta'delta2. The delta2 factor had a molecular weight of around 20,000. The delta-containing enzymes have a higher affinity for the DNA-cellulose column and a higher specific activity on various templates than vegetative holoenzyme. The simultaneous appearance of these enzymes with vegetative holoenzymes in sporulating cells is consistent with the data found previously with DNA-RNA hybridization studies, which showed that sporulating cells contained both vegetative and sporulation messenger RNAs.
Role of the rel gene product in the control of cyclic adenosine 3',5'-monophosphate accumulation
Authors: Braedt G , Gallant J
Published: January 2020

The presence of a relA mutant allele affects the kinetics of cyclic adenosine 3',5'-monophosphate accumulation during downshift from glucose to succinate. The nucleotide accumulates at the normal rate early in the downshift transition but continues to accumulate for a longer time in the relA mutant, leading to a two- to threefold excess by the end of the diauxic lag. Evidence is presented that this effect occurs independently of the accumulation of ppGpp.
Tyramine oxidase and regulation of arylsulfatase synthesis in Klebsiella aerogenes
Authors: Okamura H , Murooka Y , Harada T
Published: January 2020

The participation of tyramine oxidase in the regulation of arylsulfatase synthesis in Klebsiella aerogenes was studied. Arylsulfatase was synthesized when this organism was grown with methionine or taurine as the sulfur source (nonrepressing conditions) and was repressed by inorganic sulfate or cysteine; this repression was relieved by tyramine and related compounds (derepressing conditions). Under nonrepressing conditions, arylsulfatase synthesis was not regulated by tyramine oxidase synthesis. However, derepression of arylsulfatase and induction of tyramine oxidase synthesis by tyramine were both antagonized by glucose and other carbohydrate compounds. The derepressed synthesis of arylsulfatase, like that of tyramine oxidase, was released from catabolite repression by use of tyramine as the sole source of nitrogen. A mutant strain that exhibits constitutive synthesis of glutamine synthetase and high levels of histidase when grown in glucose-ammonium medium was subject to the catabolite repression of both tyramine oxidase and arylsulfatase syntheses. Mutants in which repression of arylsulfatase could not be relieved by tyramine could not utilize tyramine as the sole source of nitrogen and were defective in the gene for tyramine oxidase.
Relationships between cotransducible plasmids in Staphylococcus aureus
Authors: Iordănescu S
Published: January 2020

Cotransduction of two or even three plasmids was observed when a Staphylococcus aureus strain, carrying five distinct, compatible plasmids, was used as donor. An active host recombination system did not seem to be indispensable for plasmid cotransduction, since RecA+ and RecA- donors gave similar cotransduction frequencies. Analysis of plasmids carried by cotransductant clones demonstrated that a genetic interaction can take place between cotransduced plasmids, leading to new plasmids. Some of the properties of these new plasmids are discussed. Another set of experiments tested the ability of a cotransducible plasmid to allow a significant degree of multiplication of a temperature-sensitive plasmid at restrictive temperature. In an attempt to explain the results obtained, a working hypothesis suggesting a transient and reversible association of cotransducible plasmids is presented.
Stability of the plasma membrane in Saccharomyces cerevisiae enriched with phosphatidylcholine or phosphatidylethanolamine
Authors: Hossack J A , Sharpe V J , Rose A H
Published: January 2020

Spheroplasts from Saccharomyces cerevisiae NCYC 366, enriched in phosphatidylethanolamine after growth in medium supplemented with 1 mM ethanolamine, were more resistant to osmotic lysis than were spheroplasts from cells grown in the presence of 1 mM choline and enriched in phosphatidylcholine.
Transposition of a beta-lactamase locus from RP1 into Pseudomonas putida degradative plasmids
Authors: Benedik M , Fennewald M , Shapiro J
Published: January 2020

The beta-lactamase gene from the RP1 plasmid transposes into at least two Pseudomonas putida degradative plasmids. Donor strains that carry RP1 (bla+ tet+ aphA+) and a degradative plasmid yield transconjugants that have only the bla+ marker of RP1. This occurs in up to 80% of all bla+ transconjugants. Segregation of the bla+ marker requires the presence of a degradative plasmid in the donor and is only observed in transconjugants that have received degradative markers. The bla+ tet aphA transconjugants show 100% linkage of bla+ to degradative markers in conjugation,transduction, and transformation crosses. A transduction cross of an (RP1), (SAL) donor shows that 8% of all SAL plasmids also carry the transposed bla+ marker. Tn401 is the name we assign to the bla+ transposon from RP1 observed in Pseudomonas. Its identity with the RP1 bla+ transposon observed in Escherichia coli is not known. In four cases, Tn401 has inserted into the camphor genes of the CAM-OCT plasmid.