bluuebunny/crossref_metadata_2025 huggingface dataset:
Coordinate regulation of phospholipid biosynthesis in Saccharomyces cerevisiae: pleiotropically constitutive opi1 mutant
Authors: Klig L S , Homann M J , Carman G M , Henry S A
Published: January 2020

Phospholipid metabolism in the Saccharomyces cerevisiae opi1 mutant, which excretes inositol and is constitutive for the biosynthetic enzyme inositol-1-phosphate synthase (M. Greenberg, P. Goldwasser, and S. Henry, Mol. Gen. Genet. 186:157-163, 1982), was examined and compared to that of a wild-type strain. In wild-type S. cerevisiae, the phospholipid composition and the relative rates of synthesis of individual phospholipids change in response to the availability of exogenous supplies of soluble phospholipid precursors, particularly inositol. The opi1 mutant, in contrast, displays a relatively invariant phospholipid composition, and its pattern of phospholipid synthesis does not change in response to exogenous phospholipid precursors. Phosphatidylinositol synthase was not found to be regulated in either wild-type or opi1 cells. In wild-type cells, phosphatidylserine synthase and the phospholipid N-methyltransferases are coordinately repressed in response to a combination of inositol and choline. However, in opi1 cells these activities are expressed constitutively. These results suggest that the gene product of the OPI1 locus participates in the coordinate regulation of phospholipid synthesis.
Pantothenate transport in Escherichia coli
Authors: Vallari D S , Rock C O
Published: January 2020

The transport system for pantothenic acid uptake in Escherichia coli was characterized. This transport system was specific for pantothenate, had a Kt of 0.4 microM, and had a maximum velocity of 1.6 pmol/min per 10(8) cells (45 pmol/min per mg [dry weight]). Pantothenate uptake was not reduced in osmotically shocked cells or by ATP depletion with arsenate, but was reduced greater than 90% by the dissipation of the membrane electrochemical gradient with 2,4-dinitrophenol. Sodium ions stimulated pantothenate uptake (Kt, 0.8 mM) by reducing the Kt for pantothenate by an order of magnitude. Intracellular pantothenate was rapidly phosphorylated, but phosphorylation of pantothenate was not required for uptake since pantothenate was the only labeled intracellular compound concentrated by ATP-depleted, glucose-energized cells. The data were consistent with the presence of a high-affinity pantothenate permease that concentrates the vitamin by sodium cotransport.
Control of Klebsiella pneumoniae nif mRNA synthesis
Authors: Collins J J , Brill W J
Published: January 2020

Four probes, each specific for a single nif transcript, were used for an analysis of the regulation of nif mRNA synthesis. Transcription of the nifLA operon was repressed by NH4+ but not by amino acids, O2, or temperatures above 37 degrees C. The nifA gene product was required for the activation of transcription of the other nif operons but not nifLA. Synthesis of the other nif transcripts was rapidly turned off by the addition of O2, NH4+, serine, or glutamine. These regulatory effects required the nifL product. However, the nifL product was not required for the cessation of synthesis of these transcripts at elevated temperatures.
Genetic organization of the afimbrial adhesin operon and nucleotide sequence from a uropathogenic Escherichia coli gene encoding an afimbrial adhesin
Authors: Labigne-Roussel A , Schmidt M A , Walz W , Falkow S
Published: January 2020

The uropathogenic Escherichia coli KS52 strain expresses a mannose-resistant hemagglutinin AFA-I, which recognizes a human erythrocyte site distinct from the alpha-digalactoside glycosphingolipid receptor common to uropathogenic E. coli strains specifying a P adhesin. A 6.7-kilobase chromosomal DNA fragment was cloned from KS52 into pBR322 and was shown to be necessary for host cell mannose-resistant hemagglutination expression and uroepithelial cell adherence (Labigne-Roussel et al., Infect. Immun. 46:251-259, 1984). The genetic organization of the 6.7-kilobase DNA fragment was investigated by generating derivative plasmids, and the polypeptides encoded by those plasmids in isolated minicells were analyzed on polyacrylamide gel. The 6.7-kilobase insert expresses five polypeptides of molecular mass 13,000, 16,000, 18,500, 30,000, and 100,000 daltons encoded, respectively, by the afaA, afaE, afaD, afaB, and afaC genes. The five genes were localized and were shown to belong to the same transcriptional unit. The afaB, afaC, and afaE gene products are required for mannose-resistant hemagglutination expression, whereas mutations in or deletions of either afaA or afaD do not modify host mannose-resistant hemagglutination expression. The afaE gene was identified as the structural gene encoding hemagglutinin. The gene has been sequenced; it encodes a 152-residue protein containing a typical 21-residue procaryote signal sequence and a 131-residue mature polypeptide, the AFA-I adhesin.
Photodynamic inactivation and mutagenesis by angelicin (isopsoralen) or thiopyronin (methylene red) in wild-type and repair-deficient strains of bacteriophage T4
Authors: Drake J W
Published: January 2020

Photodynamic inactivation of bacteriophage T4 particles, mediated by either angelicin or thiopyronin, is enhanced by defects in the T4 uvsW-uvsX-uvsY postreplication repair system but not by a defect in the denV pyrimidine-dimer-excision system. There was no evidence for functional interactions between the two repair systems. As observed previously with 8-methoxypsoralen, photodynamic mutagenesis with angelicin is abolished by defects in the uvsW-uvsX-uvsY system.
Morphological characteristics of colony development in Micromonospora chalcea
Authors: Suarez J E , Hardisson C
Published: January 2020

Colonies of Micromonospora chalcea display two types of mycelia. Vegetative mycelia are nonbranched, have a propensity for parallel disposition, and possess infrequent septa. The reproductive mycelia develop on their apical portion and are characterized by branching, frequent septation, and bearing of spores that are either sessile or at the end of small sporophores.
Transmembrane permeability channels across the outer membrane of Haemophilus influenzae type b
Authors: Vachon V , Lyew D J , Coulton J W
Published: January 2020

Outer membranes of Haemophilus influenzae type b were fractionated to yield Triton X-100-insoluble material and lipopolysaccharide and phospholipids. Liposomes reconstituted from lipopolysaccharide and phospholipids were impermeable to sucrose (Mr, 342) and to a high-molecular-weight dextran (average Mr, 6,600). When the Triton X-100-insoluble material was introduced into the reconstituted liposomes, the vesicles became permeable to sucrose, raffinose (Mr, 504), and stachyose (Mr, 666) and fully retained dextrans of Mr greater than 1,500. Inulin (average Mr, 1,400) was tested for its efflux from the reconstituted outer membrane vesicles; 62% of the added inulin was trapped. The molecular weight exclusion limit for the outer membrane of H. influenzae type b was therefore estimated at approximately 1,400. A protein responsible for the transmembrane diffusion of solutes was purified from H. influenzae type b by extraction of whole cells with cetyl trimethyl ammonium bromide. When this extract was passed over DEAE-Sepharose, three protein-containing peaks (I, II, and III) were eluted. Peaks I and II contained mixtures of proteins as determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis; when tested for their pore-forming properties, these proteins were unable to render liposomes of lipopolysaccharide and phospholipid permeable to sucrose. Peak III contained only one molecular species of protein of molecular weight 40,000; this protein acted as a porin in reconstituted vesicles. The molecular weight exclusion limit for 40,000-molecular-weight protein matched the estimate of approximately 1,400 which was determined for outer membranes. A series of homologous saccharides of increasing degree of polymerization was prepared from agarose by hydrolysis with beta-agarase and fractionation on gel filtration chromatography. These oligosaccharides of Mr, 936, 1,242, 1,548, and 1,854 were assayed for retention by the complete vesicles containing 40-kilodalton protein and lipopolysaccharide and phospholipids. All of these oligosaccharides were lost by efflux through the porin. Since the molecular conformation of the largest oligosaccharide is an elongated semirigid helix, it is suggested that the pore formed by the 40-kilodalton protein does not act as a barrier to the diffusion of this compound.
Activation of the hole-forming toxin aerolysin by extracellular processing
Authors: Howard S P , Buckley J T
Published: January 2020

A precursor-product relationship between aerolysin and a protein with a higher molecular weight was observed in culture supernatants of Aeromonas hydrophila. The larger protein was isolated by ammonium sulfate precipitation and ion-exchange and hydroxyapatite chromatography and compared with purified aerolysin. It was at least 250 times less hemolytic than aerolysin. Both proteins had the same amino acid sequence at the amino terminus. Cyanogen bromide fragments obtained from the two were identical except that each protein contained one unique fragment, and the fragment from the larger protein was 2,500 daltons larger than the fragment obtained from aerolysin. Treatment with trypsin or with an extracellular Aeromonas protease resulted in rapid conversion of the larger protein to a form corresponding in molecular weight and activity to aerolysin. The results indicate that aerolysin is exported to the culture supernatant as a protoxin which is later activated by proteolytic removal of a peptide from the C terminus.
Cloning of the contiguous 165-kilobase-pair region around the terminus of Escherichia coli K-12 DNA replication
Authors: Asada K , Nakatani S , Takanami M
Published: January 2020

Escherichia coli K-12 chromosomal DNA was partially digested with either EcoRI or HindIII, and cosmid libraries were constructed. By screening these libraries, a series of partially overlapping clones which covered the terC region was isolated. The cloned area spanned about 165 kilobase pairs, corresponding to the 29.7-to-33.2-min region of the genetic map of the E. coli chromosome.
Genetics of methyl-accepting chemotaxis proteins in Escherichia coli: null phenotypes of the tar and tap genes
Authors: Slocum M K , Parkinson J S
Published: January 2020

The tar and tap genes are located adjacent to one another in an operon of chemotaxis-related functions. They encode methyl-accepting chemotaxis proteins implicated in tactic responses to aspartate and maltose stimuli. The functional roles of these two gene products were investigated by isolating and characterizing nonpolar, single-gene deletion mutants at each locus. Deletions were obtained by selecting for loss or a defective Mu d1 prophage inserted in either the tar or tap gene. The extent of the tar deletions was determined by genetic mapping with Southern hybridization. Representative deletion mutants were surveyed for chemotactic responses on semisolid agar and by temporal stimulation in a tethered cell assay to assess flagellar rotational responses to chemoeffector compounds. The tar deletion strains exhibited complete loss of aspartate and maltose responses, whereas the tap deletion strains displayed a wild-type phenotype under all conditions tested. These findings indicate that the tap function is unable to promote chemotactic responses to aspartate and maltose, and its role in chemotaxis remains unclear.
Bacillus subtilis gene involved in cell division, sporulation, and exoenzyme secretion
Authors: Sadaie Y , Kada T
Published: January 2020

Bacillus subtilis strains carrying div-341 or sacU mutations, or both, have been characterized to reveal the roles of both genes in the initiation of sporulation, as well as in cell division and exoenzyme secretion. Both mutations were closely linked by transformation and caused the pleiotropic effects on sporulation and sporulation-associated events. Some sacU mutations (sacUh) resulted in hyperproduction of exoenzymes, reduced autolysis, and an ability to sporulate in the presence of excess nutrients. The div-341 mutation, on the other hand, resulted in filamentous growth at a higher temperature (45 degrees C) and showed spo0 properties at an intermediate permissive temperature (37 degrees C) in the usual sporulation medium. However, the div-341 strain sporulated better than wild-type strain at 37 degrees C in the presence of excess nutrients. Exoenzyme production and autolysis were reduced at 37 degrees C in the div-341 strain. A double mutant with sacUh32 and div-341 showed the complex phenotypes. It showed the sacUh32 property of autolysis and exoenyzme secretion. It showed the sacUh32 property of sporulation at 30 degrees C and the div-341 property at 37 degrees C. Slow growth and defective spore outgrowth of the div-341 strain at 37 degrees C were not observed in the double-mutant strain. Based on pleiotropic phenotypes and close linkages of both mutations, we discuss the relationship between the sacU and div-341 genes and their roles in sporulation, exoenzyme secretion, and cell division.
Heat and UV light resistance of vegetative cells and spores of Bacillus subtilis Rec-mutants
Authors: Hanlin J H , Lombardi S J , Slepecky R A
Published: January 2020

The heat and UV light resistance of spores and vegetative cells of Bacillus subtilis BD170 (rec+) were greater than those of B. subtilis BD224 (recE4). Strain BD170 can repair DNA whereas BD224 is repair deficient due to the presence of the recE4 allele. Spores of a GSY Rec+ strain were more heat resistant than spores of GSY Rec- and Uvr- mutants. The overall level of heat and UV light resistance attained by spores may in part be determined by their ability to repair deoxyribonucleic acid after exposure to these two physical mutagens.
Expression of Rhizobium trifolii early nodulation genes on maize and rice plants
Authors: Plazinski J , Innes R W , Rolfe B G
Published: January 2020

An IncQ multicopy vector (pKT230) and an IncP1 low-copy-number vector (pRK290), both carrying Rhizobium trifolii root hair curling (Hac) genes, were transferred to a Sym plasmid-cured derivative of R. trifolii ANU843. The resulting transconjugants were used to inoculate the monocotyledonous plants sorghum, maize, rice, and wheat. Transconjugants carrying the Hac genes on the multicopy vector caused a root hair curling response on maize and rice plants 14 days after inoculation.
Characterization of the diphtheria tox transcript in Corynebacterium diphtheriae and Escherichia coli
Authors: Leong D , Murphy J R
Published: January 2020

Transcription of the tox gene in lysogenic Corynebacterium diphtheriae strains C7(beta tox+), C7 (gamma tox) and the hypertoxigenic PW8 (omega tox+) was analyzed and compared with transcription of the C. diphtheriae tox gene in the recombinant strain Escherichia coli (pDT201). In all cases S1 nuclease mapping localized the 5' terminus of the tox mRNA to a site 8 or 9 base pairs (bp) downstream of a region similar to the -10 consensus sequence of E. coli promoters. In C. diphtheriae the tox transcript was observed only in strains that were grown under iron-limiting conditions; in the presence of excess iron, transcription beyond bp 38 of the tox coding region was not observed. In contrast, in E. coli(pDT201) tox was expressed at equivalent levels in both iron-depleted and iron-supplemented media. The DNA insertion in the tox gene of the nontoxigenic corynephage gamma was found to occur at bp 54 of the tox coding region. The insertion event resulted in the duplication of a 7-bp target sequence, and the ends of the insert were found to constitute an imperfect inverted repeat of approximately 26 bp. Transcription from the tox promoter in C7(gamma tox) was found to initiate at the same nucleotides as in C7(beta tox+), PW8, and E. coli(pDT201) and remained sensitive to iron inhibition. These observations are discussed in relation to the mechanism of iron-mediated regulation of the tox gene.
Characterization and solubilization of the membrane-bound ATPase of Mycoplasma gallisepticum
Authors: Linker C , Wilson T H
Published: January 2020

The membrane-bound ATPase of Mycoplasma gallisepticum selectively hydrolyzed purine nucleoside triphosphates and dATP. ADP, although not a substrate, inhibited ATP hydrolysis. The enzyme exhibited a pH optimum of 7.0 to 7.5 and an obligatory requirement for divalent cations. Dicyclohexylcarbodiimide at a concentration of 1 mM inhibited 95% of the ATPase activity at 37 degrees C, with 50% inhibition occurring at 22 microM dicyclohexylcarbodiimide. Sodium or potassium (or both) failed to stimulate activity by greater than 37%. Azide (2.6 mM), diethylstilbestrol (100 micrograms/ml), p-chloromercuribenzoate (1 mM), and vanadate (50 microM) inhibited 50, 91, 89, and 60%, respectively. The ATPase activity could not be removed from the membrane without detergent solubilization. Although most detergents inactivated the enzyme, the dipolar ionic detergent N-dodecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (0.1%) solubilized approximately 70% of the enzyme with only a minor loss in activity. The extraction led to a twofold increase in specific activity and retention of inhibition by dicyclohexylcarbodiimide and ADP. Glycerol greatly increased the stability of the solubilized enzyme. The properties of the membrane-bound ATPase are not consistent with any known ATPase. We postulate that the ATPase functions as an electrogenic proton pump.
supN ochre suppressor gene in Escherichia coli codes for tRNALys
Authors: Uemura H , Thorbjarnardóttir S , Gamulin V , Yano J , Andrésson O S , Söll D , Eggertsson G
Published: January 2020

We describe the cloning and nucleotide sequence of a new tRNALys gene, lysV, in Escherichia coli. An ochre suppressor allele of this gene, supN, codes for a tRNALys with anticodon UUA, presumably derived by a single base change from a wild-type UUU anticodon. The sequence of the supN tRNALys is identical to the sequence of ochre suppressor tRNAs encoded by mutant alleles at the lysT locus. This locus, which contains the two previously known tRNALys genes of E. coli, is located far from the lysV locus on the chromosome.
Antigenic mosaic of Methanosarcinaceae: partial characterization of Methanosarcina barkeri 227 surface antigens by monoclonal antibodies
Authors: Garberi J C , Macario A J , De Macario E C
Published: January 2020

Hybridomas were constructed with spleen cells from mice immunized against Methanosarcina barkeri 227. The reaction with the resulting monoclonal antibodies identified two antigenic determinants. Determinant 8A is present in M. barkeri 227, where it is accessible to antibody on whole bacterial cells. 8A is undetectable in (or absent from) M. barkeri R1M3, an immunologically closely related strain. Determinant 8C is present in both strains, but with M. barkeri 227 it is found only in extracts and cannot be demonstrated in whole cells. It therefore appears to be hidden. A soluble form of antigen 8A (antigen 227) was obtained treating whole M. barkeri 227 cells with absolute methanol. This antigen was further purified by affinity chromatography with antibody 8A. Chemical and immunochemical analyses of these preparations showed that antigen 227 is a high-molecular-weight (4 X 10(5)) structure composed mainly of one carbohydrate, glucose, and small amounts of amino acids. Its solubility properties suggest that this molecule is associated with a lipid moiety.
Mechanism of ethanol inhibition of fermentation in Zymomonas mobilis CP4
Authors: Osman Y A , Ingram L O
Published: January 2020

Accumulation of alcohol during fermentation is accompanied by a progressive decrease in the rate of sugar conversion to ethanol. In this study, we provided evidence that inhibition of fermentation by ethanol can be attributed to an indirect effect of ethanol on the enzymes of glycolysis involving the plasma membrane. Ethanol decreased the effectiveness of the plasma membrane as a semipermeable barrier, allowing leakage of essential cofactors and coenzymes. This leakage of cofactors and coenzymes, coupled with possible additional leakage of intermediary metabolites en route to ethanol formation, is sufficient to explain the inhibitory effects of ethanol on fermentation in Zymomonas mobilis.
Delineation of two distinct regulatory domains in the 5' region of the nar operon of Escherichia coli
Authors: Li S , Rabi T , DeMoss J A
Published: January 2020

A detailed restriction site map was determined for an 8.4-kilobase DNA fragment containing the 5' regulatory and promoter region of the nar operon of Escherichia coli. The 5' end of the nar operon was subcloned as a 2.5-kilobase fragment, and an intact nar operon was constructed from this subcloned fragment and an EcoRI fragment containing the remainder of the nar operon. A set of Bal 31 deletions extending into the 5' region of the intact operon was selected, mapped, and characterized. Based on the synthesis of the alpha and beta subunits of nitrate reductase in a nar::Tn5 mutant, three categories of deletions were found: (i) those which permitted normal expression, (ii) those which completely prevented expression, and (iii) those which permitted anaerobic expression of the operon but prevented any additional induction by nitrate. The nucleotide sequence was determined for a segment of the nar promoter region starting at one of the latter deletion end points and extending into the first structural gene of the operon. The position of the deletion end point relative to the translation start site for the first structural gene, narG, was defined by identifying the nucleotide sequence for the first 20 N-terminal amino acid residues of the alpha subunit of nitrate reductase. Deletions terminating 161 base pairs (bp) and approximately 200 bp upstream from the narG translation start site permitted anaerobic formation of nitrate reductase but interfered with the stimulation of nar operon expression by nitrate. A maximum size for the regulatory region was defined by two Tn5 insertions, which mapped approximately 550 bp 5' from the translation start site and did not interfere with the normal expression of nitrate reductase under anaerobic conditions with or without nitrate. We conclude that the nar operon 5' regulatory region is divided into two distinct regions: the 100 to 150 bp immediately 5' to the narG gene include a transcriptional start site and the signals necessary for anaerobic expression of the operon, and an adjacent region of 50 to 400 bp is required for the stimulation of operon expression by nitrate.
Oxidation of protoporphyrinogen in the obligate anaerobe Desulfovibrio gigas
Authors: Klemm D J , Barton L L
Published: January 2020

The anaerobic oxidation of protoporphyrinogen to protoporphyrin was demonstrated in extracts of Desulfovibrio gigas. Protoporphyrin formation occurred in the presence of nitrite, hydroxylamine, sulfite, thiosulfate, ATP plus sulfate, NAD+, NADP+, flavin adenine dinucleotide, flavin mononucleotide, fumarate, 2,6-dichlorophenol-indophenol, methyl viologen, and 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide. With dialyzed cell extracts, highest activities were observed with sulfite, NAD+, and NADP+ as electron acceptors. The enzyme for protoporphyrinogen oxidation was localized in the membrane of D. gigas and displayed optimal activity at pH 7.3 and 28 degrees C.
New view of the surface projections of Chlamydia trachomatis
Authors: Nichols B A , Setzer P Y , Pang F , Dawson C R
Published: January 2020

Two kinds of surface specializations of chlamydiae have been described: hemispheric projections and spikelike rods. We undertook the present studies to demonstrate chlamydial ultrastructure in greater detail in conventional thin-sectioned specimens. Chlamydia trachomatis (LGV strain L2/434/Bu), cultured for 40 h in L929 mouse fibroblasts, was fixed in glutaraldehyde-acrolein, p-formaldehyde-glutaraldehyde, or glutaraldehyde-osmium tetroxide mixtures, postfixed in osmium tetroxide, stained in uranyl acetate, dehydrated in ethanols, and embedded in Epon. By the use of fixatives that penetrate and fix rapidly, chlamydial outer and plasma membranes were clearly revealed. Our results indicate that the hemispheric projections are specializations of the plasma membrane of elementary bodies. The spikelike projections are found in intermediate forms, originate beneath depressions of the plasma membrane, and extend through the periplasmic space and outer membrane to end with pointed tips. Improved preservation of chlamydiae provides a new, informative view of their complex structure. Significant interactions between chlamydiae and host cells might be influenced by the surface structures shown in this study.
Regulation of the glucose phosphotransferase system in Brochothrix thermosphacta by membrane energization
Authors: Singh S P , Bishop C J , Vink R , Rogers P J
Published: January 2020

Uptake of 2-deoxyglucose, alpha-methylglucopyranoside, and glucose into intact cells of Brochothrix thermosphacta (formerly Microbacterium thermosphactum, ATCC 11509) was stimulated by KCN or CCCP. The glucose analogs were recovered almost totally as the sugar phosphates. Membrane vesicles were isolated from protoplasts and shown to be right side out by freeze fracturing and by using ATPase as a marker for the cytoplasmic membrane surface. Uptake of glucose into vesicles was dependent on the presence of phosphoenolpyruvate. NADH oxidation, K+ -diffusion gradients, and externally directed lactate gradients (pH greater than 7 initially) were used to generate transmembrane potentials across membrane vesicles. Above a threshold value of about -50 mV, uptake of glucose into membrane vesicles was reduced. Likewise, the maximum uptake of glucose and its two analogs into cells occurred when the protonmotive force was less than about -50 mV.
Circular mitochondrial genome of Candida albicans contains a large inverted duplication
Authors: Wills J W , Troutman W B , Riggsby W S
Published: January 2020

The mitochondrial DNA (mtDNA) of the dimorphic fungus Candida albicans has a molecular size of 41 kilobase pairs as judged by summation of the fragment sizes produced by digestion with restriction endonucleases EcoRI, PvuII, and a combination of both enzymes. Five of the six EcoRI fragments comprising the mitochondrial genome have been cloned into the plasmid vector, pBR322. Restriction mapping revealed a circular map as predicted by previous observations with the electron microscope. The use of nick-translated, purified mtDNA to probe digests of mtDNA from other strains of C. albicans revealed a common restriction pattern. Use of nick-translated, cloned EcoRI fragments to probe digests of mtDNA revealed a large (at least 5 kilobase pairs), inverted duplication as well as a smaller (less than 0.4 kilobase pairs) region of related sequences.
Self-cloning in Streptomyces griseus of an str gene cluster for streptomycin biosynthesis and streptomycin resistance
Authors: Ohnuki T , Imanaka T , Aiba S
Published: January 2020

An str gene cluster containing at least four genes (strR, strA, strB, and strC) involved in streptomycin biosynthesis or streptomycin resistance or both was self-cloned in Streptomyces griseus by using plasmid pOA154. The strA gene was verified to encode streptomycin 6-phosphotransferase, a streptomycin resistance factor in S. griseus, by examining the gene product expressed in Escherichia coli. The other three genes were determined by complementation tests with streptomycin-nonproducing mutants whose biochemical lesions were clearly identified. strR complemented streptomycin-sensitive mutant SM196 which exhibited impaired activity of both streptomycin 6-phosphotransferase and amidinotransferase (one of the streptomycin biosynthetic enzymes) due to a regulatory mutation; strB complemented strain SD141, which was specifically deficient in amidinotransferase; and strC complemented strain SD245, which was deficient in linkage between streptidine 6-phosphate and dihydrostreptose. By deletion analysis of plasmids with appropriate restriction endonucleases, the order of the four genes was determined to be strR-strA-strB-strC. Transformation of S. griseus with plasmids carrying both strR and strB genes enhanced amidinotransferase activity in the transformed cells. Based on the gene dosage effect and the biological characteristics of the mutants complemented by strR and strB, it was concluded that strB encodes amidinotransferase and strR encodes a positive effector required for the full expression of strA and strB genes. Furthermore, it was found that amplification of a specific 0.7-kilobase region of the cloned DNA on a plasmid inhibited streptomycin biosynthesis of the transformants. This DNA region might contain a regulatory apparatus that participates in the control of streptomycin biosynthesis.
Integration of bacteriophage SP24 into the chromosome of group A streptococci
Authors: Spanier J G , Cleary P P
Published: January 2020

The group A streptococcal bacteriophage SP24 contains a unique phage att site and integrates into a common chromosomal locus in two unrelated group A streptococcal strains, CS24 and CS112. Southern blot analysis suggested that the terminally redundant phage DNA recombines to form the unit-length genome observed in the prophage state. Phage DNA integration appears to be required for stable lysogen formation and conversion to the M+ state; however, the precise role of the bacteriophage and the relationship of phage integration to increased M protein synthesis are unclear.
New class of limited-host-range Agrobacterium mega-tumor-inducing plasmids lacking homology to the transferred DNA of a wide-host-range, tumor-inducing plasmid
Authors: Unger L , Ziegler S F , Huffman G A , Knauf V C , Peet R , Moore L W , Gordon M P , Nester E W
Published: January 2020

Biotype 1 and 2 strains of Agrobacterium tumefaciens were isolated from crown gall tumors of Lippia canescens plants growing as ground cover in Arizona. The isolates were agrocin 84 sensitive, did not catabolize octopine, nopaline, agropine, or mannopine, and were limited in their tumorigenic host range. One biotype 2 strain, AB2/73, showed the most limited host range; it incited tumors only on Lippia strains, the cucurbit family of plants, and Nicotiana glauca. Megaplasmids were detected in the isolates by vertical agarose gel electrophoresis. The unusual host range, as well as sensitivity to agrocin 84, were plasmid specified since they were conjugally cotransferred with plasmids from donor strain AB2/73. Correlation of deletions with concomitant loss of virulence and agrocin 84 sensitivity identified the megaplasmid pAtAB2/73d as the virulence element in strain AB2/73. The estimated size of this tumor-inducing plasmid was 500 kilobases. Axenic growth of tumor tissue incited by strains carrying pAtAB2/73d was phytohormone independent. Although the limited-host-range megaplasmid pAtAB2/73d lacked any detectable homology to the phytohormone-biosynthetic genes in wide-host-range transferred DNA (tms-1, tms-2, tmr), it showed homology to the wide-host-range virB, virC, virD, and virG loci. Therefore, pAtAB2/73d represents a new class of tumor-inducing plasmids distinguished by its large size, the absence of determinants for the catabolism of several known opines, the presence of agrocin 84 sensitivity, and its lack of homology to wide-host-range transferred DNA contrasted with its conservation of sequences from the wise-host-range vir region.
Inhibition of growth of Rhizobium japonicum by cyclic GMP
Authors: Jones B L , Agarwal A K , Keister D L
Published: January 2020

Exogenous cyclic guanosine-3',5'-monophosphate (cGMP) inhibited the growth of Rhizobium japonicum at less than 100 microM. Other nucleotides, including cyclic AMP, cyclic IMP, and cyclic CMP, had no inhibitory effect even at higher concentrations nor was the inhibition by cGMP reversed by cyclic AMP. The inhibitory effect was independent of the carbon and nitrogen source(s) used. cGMP did not inhibit the growth of any other species of bacterium tested, including several fast-growing Rhizobium species. The kinetics of growth inhibition are multiphasic, with no apparent effect for several hours after addition, followed by a period of total inhibition. Subsequently, growth resumed at a slower rate. Resumption of growth was not due to destruction of the nucleotide. Studies of the intracellular cGMP concentration did not reveal significant changes in cells grown under aerobic or microaerobic conditions. No effect of cGMP on the derepression of respiratory nitrate reductase was observed.
DNA supercoiling and suppression of the leu-500 promoter mutation
Authors: Pruss G J , Drlica K
Published: January 2020

top mutations (formerly supX) eliminate DNA topoisomerase I activity and suppress the leu-500 promoter mutation in Salmonella typhimurium (K. M. Overbye, S. K. Basu, and P. Margolin, Cold Spring Harbor Symp. Quant. Biol. 47:785-791, 1983). Sublethal doses of coumermycin which reduce intracellular levels of supercoiling activity in a top mutant eliminated suppression of the leu-500 mutation. This result provides evidence that increased DNA supercoiling suppresses the leu-500 promoter mutation in top mutants.
Chromosomal and plasmid locations for phosphoribulokinase genes in Alcaligenes eutrophus
Authors: Klintworth R , Husemann M , Salnikow J , Bowien B
Published: January 2020

Genes coding for phosphoribulokinase (PRK), a key enzyme of the Calvin cycle, were localized in the genome of the chemoautotroph Alcaligenes eutrophus. The NH2-terminal sequence of the PRK subunit was determined. With a synthetic oligodeoxynucleotide probe complementary to a portion of this sequence, hybridization analysis revealed PRK genes to be located on both the chromosome and the megaplasmid pHG1 of A. eutrophus H16.
Chemical and immunological analysis of the complex structure of Escherichia coli alpha-hemolysin
Authors: Bohach G A , Snyder I S
Published: January 2020

Escherichia coli alpha-hemolysin (AH) purified from culture supernatants by gel filtration and ion-exchange chromatography was heterogeneous in charge and size. A 107,000-dalton protein was identified as the product of the hlyA gene by its reactivity with anti-AH monoclonal antibodies. Proteolysis of the product of the hlyA gene occurred but was not required for transport of the protein through the cell wall. Active AH had a larger size and lower pI than analysis of the hlyA gene sequence would predict, thus suggesting that the hlyA protein is complexed with other bacterial products. Lipopolysaccharide was detected in purified hemolysin complex preparations and may be a major component of the complexes. These findings suggest several possible mechanisms for release of AH from the bacterial cell including release by outer membrane fragmentation. The existence of AH complexed with lipopolysaccharide may have important implications in understanding its toxicity.
Toxicity and mutagenicity of plumbagin and the induction of a possible new DNA repair pathway in Escherichia coli
Authors: Farr S B , Natvig D O , Kogoma T
Published: January 2020

Actively growing Escherichia coli cells exposed to plumbagin, a redox cycling quinone that increases the flux of O2- radicals in the cell, were mutagenized or killed by this treatment. The toxicity of plumbagin was not found to be mediated by membrane damage. Cells pretreated with plumbagin could partially reactivate lambda phage damaged by exposure to riboflavin plus light, a treatment that produces active oxygen species. The result suggested the induction of a DNA repair response. Lambda phage damaged by H2O2 treatment were not reactivated in plumbagin-pretreated cells, nor did H2O2-pretreated cells reactivate lambda damaged by treatment with riboflavin plus light. Plumbagin treatment did not induce lambda phage in a lysogen, nor did it cause an increase in beta-galactosidase production in a dinD::Mu d(lac Ap) promoter fusion strain. Cells pretreated with nonlethal doses of plumbagin showed enhanced survival upon exposure to high concentrations of plumbagin, but were unchanged in their susceptibility to far-UV irradiation. polA and recA mutants were not significantly more sensitive than wild type to killing by plumbagin. However, xth-1 mutants were partially resistant to plumbagin toxicity. It is proposed that E. coli has an inducible DNA repair response specific for the type of oxidative damage generated during incubation with plumbagin. Furthermore, this response appears to be qualitatively distinct from the SOS response and the repair response induced by H2O2.
SYNTHESIS AND DEGRADATION OF POLY-β-HYDROXYBUTYRIC ACID IN CONNECTION WITH SPORULATION OF
BACILLUS MEGATERIUM
Authors: Slepecky Ralph A. , Law John H.
Published: January 2020

Slepecky, Ralph
A. (Northwestern University, Evanston, Ill.),
and John H. Law
. Synthesis and degradation of poly-β-hydroxybutyric acid in connection with sporulation of
Bacillus megaterium
. J. Bacteriol.
82:
37–42. 1961.—The production of poly-β-hydroxybutyrate has been followed in
Bacillus megaterium
, a sporulating strain, and
B. megaterium
strain KM, a nonsporulating strain, by an improved assay procedure and by the use of C
14
-acetate.

The production of polymer in the KM strain follows the growth curve very slowly and reaches a peak at the time the cells are entering the stationary phase of growth. Slow utilization of polymer follows.

When the sporulating strain is grown under conditions favorable for polymer production, no spores are formed; polymer production and utilization follow kinetics similar to those observed with asporogenous strains.

When the sporulating strain is grown under conditions unfavorable for polymer production but favorable for sporulation, less polymer is produced and peak production occurs during the log phase of growth. Rapid utilization of the polymer precedes sporulation.

If the medium is made favorable for polymer production by the addition of glucose and acetate and vigorous aeration conditions are used, sporulation can be obtained after good polymer production and subsequent utilization.
SPONTANEOUS AND MUTATOR-INDUCED REVERSIONS OF AN
ESCHERICHIA COLI
AUXOTROPH II
Authors: Bacon Donald F. , Treffers Henry P.
Published: January 2020

Bacon, Donald
F. (Yale University, New Haven, Conn.),
and Henry P. Treffers
. Spontaneous and mutator-induced reversions of an
Escherichia coli
auxotroph. II. Acetylornithinase activity associated with the different revertant types. J. Bacteriol.
82:
48–53. 1961.—In a preceding communication it was shown that three principal groups of spontaneous revertants from an ornithine-requiring strain of
Escherichia coli
could be distinguished on the basis of their growth characteristics. They were designated as fast (F) (identical with the wild type), slow-48 (
S
48
), and slow-72 (
S
72
). The present paper presents data on the acetylornithinase activities as well as precursor accumulations of typical revertants from each group.

The enzymatic activity associated with extracts of F revertants did not differ significantly from those of the wild type; the mean activity of extracts from the wild-type and F revertants was 23 units per mg of protein; the mean activity of S
48
revertant extracts was 0.4 units per mg of protein and, similarly, that of the S
72
revertant extracts was 0.06 units per mg of protein. These are, respectively, 1/50 and 1/350 of the wild-type activity.

It was estimated that an S
48
culture in minimal broth accumulated 16 μg of
N
α
-acetylornithine per ml and that an S
72
culture accumulated 60 μg per ml of this compound. Accumulation of this precursor in an F revertant culture was not detected by the assay procedure employed.

In an earlier communication we reported that both the S
48
and S
72
revertant types exhibited increasing rates of growth when the growth in minimal broth was followed photometrically Supplements of
N
α
-acetylornithine and of a sterile supernatant from an S
48
revertant culture which were incorporated into minimal broth failed to modify the unusual curvilinear nature of the growth curve.

The data on the enzymatic activities and precursor accumulations support the original classification of revertant groups on the basis of growth rates. The total information at hand is consistent with the notion that reversion from an auxotrophic requirement may result in at least three distinct revertant types, each characterized by a unique growth rate, enzymatic activity, and precursor accumulation.
ENZYME SYSTEMS IN THE MYCOBACTERIA XI
Authors: Bastarrachea Fernando , Anderson David G. , Goldman Dexter S.
Published: January 2020

Bastarrachea, Fernando
(University of Wisconsin, Madison),
David G. Anderson, and Dexter S. Goldman
. Enzyme systems in the mycobacteria. XI. Evidence for a functional glycolytic system. J. Bacteriol.
82:
94–100. 1961.—Cell-free extracts of the H37Ra strain of
Mycobacterium tuberculosis
contain the enzymes, aldolase, phosphohexokinase, phosphohexoisomerase, and phosphoglucomutase. The first three enzymes have been purified; the characteristics of all these enzymes have been studied. The enzymes are similar to those isolated from animal tissue. A functional glycolytic system in the mycobacteria provides a mechanism for the formation of other metabolites from glycerol.
EFFECTS OF DEOXYRIBONUCLEIC ACID PRODUCTS ON RESPIRATION OF VIRULENT AND AVIRULENT PNEUMOCOCCI
Authors: Firshein W.
Published: January 2020

Firshein
, W. (Wesleyan University, Middletown, Conn.). Effects of deoxyribonucleic acid products on respiration of virulent and avirulent pneumococci. J. Bacteriol.
82:
181–186. 1961.—In the presence of deoxyribonucleic acid (DNA) + deoxyribonuclease + mixtures of deoxynucleosides and deoxynucleotides (supplement-1) which had previously been shown to enhance DNA synthesis in virulent (S) pneumococci without affecting such synthesis in avirulent (R) pneumococci, a significant enhancement of glucose oxidation was observed over control levels in S cells of types I, II, and III. In contrast, this supplement either depressed oxygen uptake or had no effect when R or weakly virulent (I) pneumococci were present. In the absence of glucose, S cells were unable to oxidize supplement-1 extensively, whereas R cells exhibited definite activity in this respect. Supplement-1 enhanced glucose oxidation specifically and was not oxidized in the process. The selective advantage produced by the DNA products in S cells could not be explained on the basis of nitrogen content, since a substance containing twice as much of this element as that found in the entire supplement did not enhance oxygen uptake to the extent that was observed with supplement-1.
TAXONOMICALLY SIGNIFICANT COLOR REACTIONS OF
BREVIBACTERIUM LINENS
Authors: Grecz Nicholas , Dack Gail M.
Published: January 2020

Grecz, Nicholas
(University of Chicago, Chicago, Ill.), and
Gail M. Dack
. Taxonomically significant color reactions of
Brevibacterium linens
. J. Bacteriol.
82:
241–246. 1961.—
Brevibacterium linens
was observed to give characteristic color reactions with certain bases and acids.

An intensive carmine-red color appeared immediately after addition of a drop of 5
n
sodium hydroxide, 5
n
potassium hydroxide, and saturated barium hydroxide. A light carmine-red was given by lithium hydroxide, and a light orange-red with a milky suspension of calcium hydroxide. No discernible color change was given with weak bases such as ammonium hydroxide, aniline, and pyridine.

A characteristic salmon-pink color was produced when
B. linens
was rubbed with a glass rod in a drop of glacial acetic acid or filter paper; a brick-red color was produced with aniline under these conditions. With syrupy phosphoric acid a green color appeared within 3 to 4 min which turned blue after approximately 3 hr. The blue color was stable for several days.

On the basis of these color reactions,
B. linens
could be distinguished from other microorganisms possessing yellow-orange pigmentation, i.e.,
Staphylococcus aureus, Staphylococcus epidermidis, Micrococcus flavus, Micrococcus citreus, Mycobacterium phlei, Sarcina lutea
. Therefore, these color changes may be used for the identification of
B. linens
. Original isolates of
B. linens
from cheese were tested by these spot reactions and all presumptive identifications could be subsequently confirmed by conventional methods. Blue and green colors appeared in all yellow-orange chromogens treated with sulfuric, perchloric, and hydrochloric acids and hence these colors were not specific for
B. linens
.
DEBARYOMYCES PHAFFII
SP. N., A NEW YEAST ISOLATED FROM A FINNISH SOIL
Authors: Capriotti Augusto
Published: January 2020

Capriotti, Augusto
(Università di Perugia, Perugia, Italy).
Debaryomyces phaffii
sp. n., a new yeast isolated from a Finnish soil. J. Bacteriol.
82:
326–330. 1961.—A new species of
Debaryomyces
is described; it was isolated from Finnish soil, and is named
Debaryomyces phaffii
sp. n., in honor of Herman J. Phaff.
SPECIFIC EFFECT OF LIMITING NUTRIENT ON PHYSIOLOGICAL EVENTS DURING CULTURE GROWTH
Authors: Ecker R. E. , Lockhart W. R.
Published: January 2020

Ecker
, R. E. (Iowa State University, Ames),
and W. R. Lockhart
. Specific effect of limiting nutrient on physiological events during culture growth. J. Bacteriol.
82:
511–516. 1961.—In cultures of
Escherichia coli
strain K12, the sequence of physiological events at the time of growth cessation in populations limited by availability of carbon source (glucose), nitrogen source (ammonium sulfate), and oxygen was observed to differ in several respects. These included differences in the relationship between mass synthesis and cell division, the utilization of nonlimiting nutrients, and the nature of changes in energy metabolism. These observations are discussed with reference to problems involved in the experimental control of variables in growth studies.
ENTHALPY CHANGES ASSOCIATED WITH THE LACTIC FERMENTATION OF GLUCOSE
Authors: Forrest W. W. , Walker D. J. , Hopgood M. F.
Published: January 2020

Forrest
, W. W. (University of Adelaide, Adelaide, South Australia), D. J.
Walker, and M. F. Hopgood
. Enthalpy changes associated with the lactic fermentation of glucose. J. Bacteriol.
82:
685–690. 1961.—The heat produced during the fermentation of glucose by growing cultures and by washed cells of
Streptococcus faecalis
has been measured by direct calorimetry. The heat production of growing cultures gives a direct measure of the rate and amount of growth which has occurred. The enthalpy change when glucose is fermented essentially to lactic acid at 37 C is −29.1 cal per mmole of glucose, which is in agreement with the calculated value for the mixture of products formed.
PERMEABILITY OF BACTERIAL SPORES I
Authors: Black S. H. , Gerhardt Philipp
Published: January 2020

Black
, S. H. (The University of Michigan, Ann Arbor)
and Philipp Gerhardt
. Permeability of bacterial spores. I. Characterization of glucose uptake. J. Bacteriol.
82:
743–749. 1961.—The total uptake of glucose by masses of clean, dormant spores was measured to assess their permeability. After correction for intercellular space, packed spores of
Bacillus cereus
strain terminalis were found in 87 determinations to be permeated by glucose to 40% of their weight. The glucose uptake was relatively independent of environmental variables, and thus was concluded to occur principally through a process of passive diffusion.
SURVEY OF FOURTEEN METABOLIC INHIBITORS FOR THEIR EFFECT ON ENDOSPORE GERMINATION IN
BACILLUS SUBTILIS
Authors: Curran Harold R. , Knaysi Georges
Published: January 2020

Curran, Harold
R. (U. S. Department of Agriculture, Washington, D. C.)
and Georges Knaysi
. Survey of fourteen metabolic inhibitors for their effect on endospore germination in
Bacillus subtilis
. J. Bacteriol.
82:
793–797. 1961.—Phase contrast microscopy was used to study the effects of metabolic antagonists upon incipient spore germination in glucose agar-film microcultures. The period of observation was 1 to 2 hr. Of 14 compounds tested, only ethanol in 10% concentration (v/v) caused almost complete inhibition. Oxamic acid and
dl
-ethionine were slightly stimulatory; 6-methyl thiouracil and octyl aldehyde were without effect. The inhibiting effect of the remainder depended upon the concentration of the antagonist. The stimulating effect of glucose on germination is discussed.