Genetic control of two electrophoretic variants of glucosephosphate isomerase in the mouse (Mus musculus)

The autosomal variation and the genetic control of GPI has been determined by a comparison of electrophoretic patterns of F₁ and backcross progeny of three inbred strains of mice. The locus controlling the production of GPI in the mouse has been designated Gpi-1. Two alleles at this locus have been described and designated Gpi-1 ^a and Gpi-1 ^b, which represent, respectively, the slow and fast electrophoretic forms. Twenty-seven inbred strains of mice have been classified for these two alleles. The absence of close linkage of Gpi-1 to seven other genetic loci has been determined. It has been demonstrated that the polymorphism of Gpi-1 is widely distributed in feral mice. GPI was expressed in vitro and in four types of malignant tumors.Supported by U.S. Public Health Service Grants GM-09966, from General Medical Sciences, and GY 4193.     

Euplotes Cytoskeleton: Tubulin and Microtubular Systems in Interphase1,2

The Euplotes cytoskeleton obtained by treatment with Triton X-100 in a microtubule-stabilizing buffer has been studied by electron microscopy and SDS-polyacrylamide electrophoresis. An antiserum has been prepared using the tubulin band from preparative gels of Euplotes cytoskeletons as an antigen. This antiserum reacts with the tubulin from different ciliated protozoa but fails to recognize the vertebrate tubulin by immunoblotting. Immunoblotting studies have demonstrated a slower electrophoretic mobility for the α-tubulin of Euplotes and Oxytricha than that of Paramecium and Tetrahymena. A cytoplasmic microtubular network in Euplotes has been revealed by indirect immunoftuorescence using both an anti-α-tubulin monoclonal antibody directed against chick brain tubulin and an antiserum raised against the tubulin of Euplotes.     

Endophytic fungal entomopathogens with activity against plant pathogens: ecology and evolution

Dual biological control, of both insect pests and plant pathogens, has been reported for the fungal entomopathogens, Beauveria bassiana (Bals.-Criv.) Vuill. (Ascomycota: Hypocreales) and Lecanicillium spp. (Ascomycota: Hypocreales). However, the primary mechanisms of plant disease suppression are different for these fungi. Beauveria spp. produce an array of bioactive metabolites, and have been reported to limit growth of fungal plant pathogens in vitro. In plant assays, B. bassiana has been reported to reduce diseases caused by soilborne plant pathogens, such as Pythium, Rhizoctonia, and Fusarium. Evidence has accumulated that B. bassiana can endophytically colonize a wide array of plant species, both monocots and dicots. B. bassiana also induced systemic resistance when endophytically colonized cotton seedlings were challenged with a bacterial plant pathogen on foliage. Species of Lecanicillium are known to reduce disease caused by powdery mildew as well as various rust fungi. Endophytic colonization has been reported for Lecanicillium spp., and it has been suggested that induced systemic resistance may be active against powdery mildew. However, mycoparasitism is the primary mechanism employed by Lecanicillium spp. against plant pathogens. Comparisons of Beauveria and Lecanicillium are made with Trichoderma, a fungus used for biological control of plant pathogens and insects. For T. harzianum Rifai (Ascomycota: Hypocreales), it has been shown that some fungal traits that are important for insect pathogenicity are also involved in biocontrol of phytopathogens.     

Physical mapping of the pea chloroplast DNA and localization of the ribosomal RNA genes

The closed circular DNA of pea chloroplast has been digested with restriction endonucleases SalI, SmaI, BamHI, XbaI, XhoI, HindIII, and EcoRI. A physical restriction map of pea ctDNA has been constructed by mapping the SalI and SmaI sites. The pea ctDNA has been found to contain one set of ribosomal RNA genes by Southern hybridization of restriction endonuclease digest, R-loop studies, and DNA-DNA heteroduplex mapping. The 23 S and 16 S RNA genes are confined to a DNA region of 3.0 and 1.5 kbp, respectively. The two rRNA chains are separated by a spacer region of 2.2 kbp.     

Genetics and physiology of the rel system of Bacillus subtilis

Summary Stringent factor (ATP:GTP-3 pyrophosphotransferase) has been purified from wild type Bacillus subtilis and it has been shown that guanosine tetra- and pentaphosphate (ppGpp and pppGpp) are synthesized in vitro in the presence of ribosomes, unacylated tRNA and its specific codon, as has been demonstrated in Escherichia coli. relA, the genetic determinant for the stringent factor, has been mapped on the B. subtilis chromosome by transduction and is found between aroD and leu.The relC locus, defined by mutations which were originally selected by resistance to thiostrepton, has been mapped adjacent to spoOH in the order cysA, spoOH, relC, rif.Stringent factor and ribosomes are functional for the in vitro synthesis of (p)ppGpp in early stages of sporulation (up to at least 4 h). This contradicts the findings of other laboratories.     

Analysis of the 5′ non-coding region of rat liver S-adenosylmethionine synthetase mRNA and comparison of the Mr deduced from the cDNA sequence and the purified enzyme

A 3 kb cDNA coding for rat liver S-adenosylmethionine (AdoMet) synthetase has been isolated. The M_r of the protein has been unequivocally determined by cDNA sequencing and enzyme purification on a thiopropyl-Sepharose column. The length of the mRNA 5′ non-coding region has been defined by primer-extension analysis. The rat liver cloned cDNA has been also used to detect S-adenosylmethionine synthetase mRNA in human liver.     

Kinetics of batch-wise enzymatic cycling system for mass production of chiral compound

Kinetics of batch-wise enzymatic cycling system (oxidoreductase-catalyzed reaction system involving enzyme-coupled cofactor regeneration) has been studied covering a broad range of the conserved total cofactor concentration, [C]₀ (=NAD(P)⁺?+?NAD(P)H), based on reasonable several assumptions. It is composed of two elementary reactions, i.e. product synthesis reaction and cofactor regeneration reaction, both of which have been expressed by Michaelis–Menten type rate equations. A novel dimensionless variable, r, has been introduced, which is defined as the concentration of one of the two cofactor components, [X] (NADH⁺ or NADPH⁺), divided by [C]₀, i.e. r .e[X]/[C]₀. The following results have been obtained. (1) The fundamental equation of the batch-wise enzymatic cycling system has been transformed to a differential equation whose formula is: dr/dT?=?N(r)/D(r) (N(r) and D(r) are quadratic equations of r having different coefficients). (2) It has been elucidated that the batch-wise enzymatic cycling system has two phases, an early short transient phase followed by a long phase in quasi-steady state (QSS). (3) In the enzymatic cycling system, r converges to a definite level regardless of any initial value of r. (4) In QSS, the definite level of r nearly equals the singular solution, r_singular, of the differential equation. (5) The actual rate of the targeted product (chiral compound) formation can be calculated by Michaelis–Menten equation in which the cofactor concentration is [C]₀×r_singular instead of [C]₀. r_singular has been proposed to name “redistribution factor”. (6) It is recommended that the “unit” of the cofactor regeneration enzyme be 2–3 times more used than the “unit” of the synthesis enzyme and that [C]₀ be 15–25 times more than the K_m value. Four special cases relating to the batch-wise enzymatic cycling system have been discussed.     

Control of minicell producing cell division by cAMP-receptor protein complex in Escherichia coli.

Summary It has been established that the strain CA8000 of Escherichia coli K 12 produces minicells. This phenotype of CA8000 has been shown to be suppressed by additional mutations in cya or crp genes. Minicell production by cya ⁺ crp ⁺ min bacteria is probably a consequence of error, introduced by horizontal growth, in the selection of site on the envelope for initiation of hemispherical growth.     

Studies on the Formation of Glucosamine Acid by Acetobacter melanogenum Beijerinck and Pseudomonas fluorescens liquefaciens

d-Glucosaminic acid has recently been found to be an oxidized product of d-glucosamine formed by Ps. fluorescens. It has been revealed that many strains of oxidative bacteria can oxidize glucosamine. The formation of glucosamine acid has been recognized among a large number of strains of Pseudomonas, Acetobacter and Gluconobacter, by means of paper chromatography. Furthermore, one of these strains, A. melanogenum Beijerinck, oxidized glucosamine to glucosaminic acid with the theoretical consumption of oxygen as Ps. fluorescens liquefaciens. Glucosaminic acid was proved by isolation and identification by means of using resting cells.

The experiment of growth shows that Ps. fluorescens liq. could not secure any energy by means of the oxidation of glucosamine.     

Changes in fish species composition in Lake Naivasha,Kenya

The fish species composition in Lake Naivasha has been modified during recent years. Out of seven introduced and one indigenous species reported in 1962, only three introduced ones are found today. The elimination of species has been brought about by predation and changing ecological conditions. The most common fish species today is Sarotherodon leucosticuus. The hybridization found by previous workers between S. leucostictus x S. spilurus niger has stopped, as S. s. niger is no longer found in the lake. Most of the hybrid characters have been lost by the few surviving hybrids due to backcrossing between hybrids and between hybrids and S. leucostictus. The hybrids now mostly resemble S. leucostictus.     

Transposon mutagenesis of nuclear photosynthetic genes in Zea mays

The discovery of a new maize (Zea mays L.) transposon system, Mutator, and the cloning of the 1.4 kilobase transposon, Mul, have made feasible the isolation of nuclear photosynthetic genes which are recognized only by their mutant phenotype. Mutant maize plants which express a high chlorophyll fluorescent (hcf) phenotype due to a defect in the electron transport or photophosphorylation apparatus have been isolated following mutagenesis with an active Mutator stock. The affected genes and their products in these mutants are inaccessible to classical methods of analysis. However, mutagenesis with the Mutator transposon makes it possible to isolate these genes.Although the PSII-deficient mutant hcf3 has been thoroughly studied by classical photo-biological methods, the nature of the lesion which results in the observed phenotype has not been established. A Mutator-induced allele of hcf3 has been isolated. A fragment of genomic DNA has been identified which is homologous to Mul and co-segregates with the mutant phenotype. This fragment is expected to contain a portion of the hcf3 locus which will be used to clone the normal gene. Direct study of the gene can provide insight into the nature and function of its polypeptide product.This approach can be used to study any photosynthetic gene which has been interrupted by a transposon. The isolation of more than 100 different chemically-induced hcf mutants, most of which can not be fully characterized using classical means, indicates the wealth of information which can be obtained using a transposon tagging technique.     

Resistance to organic hydroperoxides requires ohr and ohrR genes in Sinorhizobium meliloti

Background  

Sinorhizobium meliloti is a symbiotic nitrogen-fixing bacterium that elicits nodules on roots of host plants Medicago sativa. During nodule formation bacteria have to withstand oxygen radicals produced by the plant. Resistance to H₂O₂ and superoxides has been extensively studied in S. meliloti. In contrast resistance to organic peroxides has not been investigated while S. meliloti genome encodes putative organic peroxidases. Organic peroxides are produced by plants and are highly toxic. The resistance to these oxygen radicals has been studied in various bacteria but never in plant nodulating bacteria.     

IS4 at its chromosomal site in E. coli K12

Summary IS4 DNA has been isolated in pure form. Hybridization of this DNA against restricted DNA of several E.coli K12 strains by Southern's blotting technique has shown that, in most strains, only one copy of IS4 is present. Though the restriction fragments around this site differ in size, IS4 can be shown always to be located at the same site. In one strain, one additional copy has been found in a new location. In this strain, IS4 in its original location has been retained.     

Effective Anomerisation of 2′‐Deoxyadenosine Derivatives During Disaccharide Nucleoside Synthesis

The formation of a disaccharide nucleoside (11) by O3′‐glycosylation of 5′‐O‐protected 2′‐deoxyadenosine or its N ⁶‐benzoylated derivative has been observed to be accompanied by anomerisation to the corresponding α‐anomeric product (12). The latter reaction can be explained by instability of the N‐glycosidic bond of purine 2′‐deoxynucleosides in the presence of Lewis acids. An independent study on the anomerisation of partly blocked 2′‐deoxyadenosine has been carried out. Additionally, transglycosylation has been utilized in the synthesis of 3′‐O‐β‐d‐ribofuranosyl‐2′‐deoxyadenosines and its α‐anomer.     

Loach Sperm Cells Transfer Foreign DNA Expressed in Early Development

The transfer of plasmid pcDNA3-lacZ by electrotrasfected sperm cells into loach (Misgurnus fossilis L.) ova has been studied. The lacZ gene has been found to express in 3- to 5-day-old prelarvae.     

Red cell glutamic-pyruvic transaminase gene frequencies in the region of the Po delta (Ferrara,Northern Italy)

Summary The red cell glutamic-pyruvic transaminase phenotype has been determined in 294 individuals from the region of the Po delta (Ferrara, Northern Italy). No correlation with past malarial morbidity has been detected. The gene frequencies found in this survey are similar to those reported for other Caucasian populations. One GPT ³ GPT ¹ individual has been found.Supported by a grant of the Consiglio Nazionale delle Ricerche (CNR).     

Premeiotic disruption of the Neurospora crassa malate synthase gene by native and divergent DNAs

Summary Repeat-induced point mutation (RIP) has been used to generate new mutations in the previously uncharacterised gene for malate synthase in Neurospora crassa. Molecular clones carrying the am (NADP-glutamate dehydrogenase) gene and the malate synthase gene from either N. crassa or Aspergillus nidulans have been introduced into Neurospora as ectopic duplicate copies by transformation, selecting for the am function in a deletion host. A number of meiotic progeny derived from these transformants were unable to use acetate as sole carbon source, yielded no detectable malate synthase activity and demonstrated extensive cytosine methylation of their duplicated sequences. The new locus has been designated acu-9 and has been assigned to linkage group VII.     

Cytogenetic characterization of the 4BC region on the X chromosome of Drosophila melanogaster: Localization of the mei-9, norpA and omb genes

Thirty genetic alterations, which involve the 4BC region of the Drosophila X chromosome, have been induced by ionizing radiation or by an endogenous mutator element. These mutations were recovered by screening for reversion of the dominant mutants Oce and Qd or for induction of the recessive mutants bi and rb. Among the 23 mutants generated by ionizing radiation, 20 have proven to be cytologically detectable chromosomal aberrations. Seven additional unique aberrations were generated in the Uc mutator strain. In total, 22 cytologically detectable deficiencies, 3 translocations, 1 inversion, 1 transposition, and 3 cytologically normal mutants have been recovered. Complementation analysis has permitted the cytogenetic localization of eight genes in the 4BC region. The mei-9 locus has been assigned to region 4B4-6, because this function is carried by Df (1)rb ⁴¹ but not by Df(1)bi ^D1. The norpA locus has been placed in the 4B6-C1 region based on its location between the distal breakpoints of Df(1)bi ^D2 and Df(1)rb ⁴¹. The genes lac, Qd, bi, and omb are localized to bands 4C5,6, rb to 4C6 and amb to 4C7,8. With one exception the complementation analysis has also permitted a determination of the linear sequence of these genes. This cytogenetic localization of these loci will facilitate the cloning and molecular analysis of genes controlling a key function in DNA repair and recombination (mei-9), and two fundamental neural functions (norpA and omb).     

Yolk formation in Locusta migratoria and Schistocerca gregaria: Related ligands and oocyte receptors

During vitellogenesis the transport of yolk precursor proteins, the vitellogenins (VTG), from the hemolymph into the oocyte is achieved by receptor-mediated endocytosis. Recently the receptor for the VTG of Locusta migratoria has been isolated. Now a new protocol has been developed for the purification of the VTG receptor of this locust from ovarian membranes. By CHAPS solubilization of the membranes followed by ion exchange and immunoaffinity chromatography, a 100-fold purification of the VTG receptor was achieved. The amino acid composition of the receptor protein has been determined. However, first attempts to sequence the receptor failed due to the N-terminal blocking of the molecule. With the same methods the VTG receptor of another locust, Schistocerca gregaria, has been isolated, purified, and characterized. This receptor has an apparent M_r of 186 kDa under nonreducing conditions. It recognizes L. migratoria VTG and vice versa. However, in cross-competition experiments in which the Schistocerca VTG competed with Locusta VTG for binding to the Locusta VTG receptor, the Schistocerca VTG was less efficient. Furthermore, the VTG receptor proteins of S. gregaria and L. migratoria are immunologically related as revealed by Western blotting with anti-Locusta VTG receptor antibodies. It appears that important structural elements required for efficient and specific endocytosis of VTG have been conserved. © 1994 Wiley-Liss, Inc.     

Genetic mapping of chromosomal mutations affecting the replication of the F-factor of Escherichia coli

Summary A genetic study has been performed on a set of mutations which prevent the replication of F-factors in Escherichia coli K-12. The gene affected is designated seg and has been located by transduction in the serB-thr segment of the chromosome. The seg gene does not appear to be related to the dnaC locus.