[orthosympathetic stimulation after hypercapnia in the rat]. | inhalation of a gas mixture : co2, 25% -- o2, 37.5% -- n2, 37.5%, provokes regularly in the light anaesthetized rat, an increase of catecholaminemia of central origin, associated with systemic arterial hypertension. | 1979 | 92225 |
intracellular ph transients induced by chloride substitution in cardiac purkyne fibres [proceedings]. | | 1979 | 92940 |
in vitro production of rauscher murine leukemia virus: influence of culture age on biological properties. | large-scale production and concentration procedures have been standardized to study the biological properties of rauscher leukemia virus produced from the high-passaged jls-v9-h mouse bone marrow cell line. virus produced early (days 4 to 6) in the harvest and refeed cycle contained higher levels of ribonucleic acid-directed deoxyribonucleic acid polymerase activity and was more infectious than rauscher leukemia virus produced later (days 7 to 10) in the growth period. the peak of virus producti ... | 1979 | 93428 |
characterization of the coronary vasodilator and hemodynamic actions of monensin, a carboxylic ionophore. | the effects of monensin on coronary blood flow (cbf) and other hemodynamic parameters were studied in anesthetized dogs. a dose-response relationship was established, and it was found that the lowest doses of monensin (5-25 micrograms/kg) produced a dose-dependent increase (3-5x) in cbf with a concomitant decrease in total peripheral resistance (tpr). pretreatment with diphenhydramine, atropine, indomethacin, or propranolol resulted in no reduction in peak increase in cbf or in the duration of r ... | 1979 | 94374 |
hereditary alpha 2-macroglobulin deficiency. | on screening of a normal material 1 man was found (age 37) who on repeated determinations had a low alpha 2m, namely 25 % with electroimmuno assay according to laurell. investigation of the family revealed that the mother (age 69) and one daughter (age 5) had low values too. all other coagulation and fibrinolytic components were normal. they had no signs of increased fibrinolysis and normal levels of alpha 2-antiplasmin, alpha 1-antitrypsin and antithrombin iii. liver function tests were normal. ... | 1979 | 94459 |
delayed neurotoxicity of o-alkyl o-aryl phenylphosphonothioate analogues related to leptophos administered orally to the hen. | | 1979 | 94601 |
production of anti-antipyrine antibody by immunization with 4-azoantipyrine-conjugated bovine serum albumin. | | 1978 | 103791 |
ultrastructural alterations in experimental lingual leukoplakia and carcinoma. | epidermoid carcinomas, preceded by dysplastic leukoplakic lesions, were produced on the right lateral borders of the tongues of syrian hamsters by the application, three times per week, of dmba in acetone after the area had been scratched with a root canal broach. animals were killed at 12 to 13 weeks and 15 to 16 weeks. electron microscopic studies of both the dysplastic leukoplakic lesions and the well-differentiated epidermoid carcinomas revealed clumping of tonofilaments and widening of inte ... | 1979 | 107501 |
studies on allergenic algae of delhi area: botanical aspects. | to study distribution of algae in and around delhi aerobiological surveys were undertaken for two consecutive years (september, 1972, to august, 1974). the surveys were accomplished by (a) slide exposure method and (b) culture plate exposure method. a total of 850 slides were exposed using durham's gravity sampling device. of these, 560 slides were exposed during 1973 (272 slides at two meter and 288 at ten meter height) and the rest (290 slides) were exposed during 1974 at ten meter height. a t ... | 1979 | 107835 |
[super-selective cerebral angiography. iii. diagnostic use and therapeutic possibilities of the telescopic catheterization technic in the circulation area of the external carotid artery in man]. | the diagnostic value and technical versatility of the previously described telescopic catheter system was demonstrated in 15 patients by super-selective angiography of the external carotid artery. it was possible in all patients to catheterise the individual branches with the f-catheter; the polyethylene-s-catheter could then be passed 3 to 5 cm, beyond the tip of the f-catheter. in almost half the patients, spasm of the injected artery was observed, particularly of the superficial temporal and ... | 1976 | 134945 |
effect of human immunoglobulin preparations on fc rosette formation between anti-d-coated erythrocytes and lymphocytes. | human immunoglobulin (ig) preparations were tested for their inhibitory effect on fc rosette formation between anti-d-coated human erythrocytes and lymphocytes, as compared to their complement activating capacity. both of the two biological activities ascribed to the sites in the fc portion of the igg molecules were found to be reduced in the pepsin-treated, as well as in the s-sulfonated ig preparations, as compared to the activities of the normal human ig preparation. in the plasmin-treated ig ... | 1978 | 150144 |
fine structural analysis of rabbit synovial cells. ii. fine structure and rosette-forming cells of explant and monolayer cultures. | the fine structure and plasma membrane receptors of explant and monolayer cells of normal rabbit synovium were studied. in explants about 10% of the cells were round and formed rosettes with igc and c3 markers, whereas the remaining cells were stellate, resembled young fibroblasts, and had no receptors for igg and complement. monolayer cells looked like fibroblasts, produced fine extracellular fibrils and hyaluronate, and formed no rosettes. thus early cultures contain both macrophages and fibro ... | 1976 | 181009 |
vestibulo-ocular reflex from the posterior canal nerve to extraocular motoneurons in the cat. | in the anesthetized cat, the posterior canal nerve (pcn) was stimulated by electric pulses and synaptic responses were recorded intracellularly in the three antagonistic pairs of extraocular motoneurons. pure reciprocal effects were obtained in the motoneurons innervating the antagonistic pair of ipsilateral oblique muscles and the antagonistic pair of contralateral vertical rectus muscles. these responses consisted of low threshold disynaptic excitatory postsynaptic potentials (epsps) in either ... | 1978 | 210032 |
stimulation of erythropoiesis in a grafted animal by mouse fetal liver culture media. | erythropoietin given to polycythemic, irradiated mice receiving a bone marrow transplant restores the number of erythroid colonies produced. in this study mouse fetal liver culture media administered to polycythemic, irradiated mice also restored the number of erythroid colonies and erythropoiesis as measured by 59fe incorporation. thus, mouse fetal liver in culture produces a factor which resembles erythropoietin. | 1977 | 321232 |
osteomyelitis and arthritis caused by salmonella typhimurium in a crow. | salmonella typhimurium was isolated from an arthritic elbow joint of a crow (corvus brachyrhynchos) which also had bilateral osteomyelitis of proximal tibias. the prevalence of salmonella organisms in wild birds is reviewed briefly. | 1978 | 368353 |
[the possibility of influenza virus reproduction in cultures of insect cells]. | | 1975 | 1214662 |
sequence and structural organization of a nif a-like gene and part of a nifb-like gene of herbaspirillum seropedicae strain z78. | the deduced amino acid sequence derived from the sequence of a fragment of dna from the free-living diazotroph herbaspirillum seropedicae was aligned to the homologous protein sequences encoded by the nifa genes from azorhizobium caulinodans, rhizobium leguminosarum, rhizobium meliloti and klebsiella pneumoniae. high similarity was found in the central domain and in the c-terminal region. the h. seropedicae putative nifa sequence was also found to contain an interdomain linker similar to that co ... | 1991 | 1840608 |
cloning and characterization of the nifa gene from herbaspirillum seropedicae strain z78. | a genomic library of herbaspirillum seropedicae was constructed and screened for the nifa gene by complementation of a nifa mutant of azospirillum brasilense (fp10). a recombinant plasmid, pems1, capable of restoring acetylene reduction activity in the mutant fp10, was isolated and found to hybridize to the nifa gene of klebsiella pneumoniae. the results suggest that nifa is involved in the regulation of nif genes in h. seropedicae. | 1991 | 1913346 |
apolipoprotein b messenger rna editing is developmentally regulated and widely expressed in human tissues. | apolipoprotein b (apob) messenger rna (mrna) undergoes posttranscriptional (c to u) editing, producing tissue-specific forms of apob from the unedited (apob100) and edited (apob48) transcripts. apob mrna editing is developmentally regulated in human fetal small intestine, producing parallel changes in the synthesis and secretion of apob100 and apob48. neither fetal nor adult liver contained detectable levels (less than 1%) of edited apob mrna. by contrast, apob mrna is incrementally edited durin ... | 1990 | 2243107 |
ammonium inhibition of nitrogenase activity in herbaspirillum seropedicae. | the effect of oxygen, ammonium ion, and amino acids on nitrogenase activity in the root-associated n2-fixing bacterium herbaspirillum seropedicae was investigated in comparison with azospirillum spp. and rhodospirillum rubrum. h. seropedicae is microaerophilic, and its optimal dissolved oxygen level is from 0.04 to 0.2 kpa for dinitrogen fixation but higher when it is supplied with fixed nitrogen. no nitrogenase activity was detected when the dissolved o2 level corresponded to 4.0 kpa. ammonium, ... | 1989 | 2498287 |
membrane protein patterns of three azospirillum species and herbaspirillum seropedicae. | membrane protein patterns in sds-page clearly characterized azospirillum amazonense, a. brasilense, a. lipoferum, and herbaspirillum seropedicae. each species showed also a typical major band with approximate molecular weights (amws) of 44, 39.5, 35.5, and 37.5 kdaltons for the four species respectively. characteristic lighter bands with amws of 63.5 and 19 kdaltons were shown by a. amazonense. similar bands of 54, 24 and 24.5 kdaltons were typical of a. brazilense, a. lipoferum and h. seropedic ... | 1989 | 2629550 |
control of diarrheal diseases. | the tremendous advances made in the control of diarrheal diseases in the past few years indicate what more can be achieved. even though the lives of an estimated three quarters of a million children are being saved each year, over three million children are still dying from readily preventable diarrheal disease. the challenge is to build on the successes thus far, to learn from experience, to promote changes in health habits that will prevent diarrhea, and to make all of these activities sustain ... | 1989 | 2655632 |
comparative study on breast milk of mothers delivering preterm and term infants--protein, fat and lactose. | milk samples were collected from 35 mothers delivering preterm infants and from 35 mothers delivering term infants at 3 time intervals over the first 3 weeks of lactation. the samples were collected by manual expression from both breasts into polyethylene containers and were frozen at -20 degrees c and stored for analysis. the protein content of preterm milks during the first and second weeks is higher than that of term milk (p less than 0.05). the fat and lactose contents during the first week ... | 1989 | 2725632 |
l-arabinose metabolism in herbaspirillum seropedicae. | the pathway for l-arabinose metabolism in herbaspirillum seropedicae was shown to involve nonphosphorylated intermediates and to produce alpha-ketoglutarate. the activities of the enzymes and the natures of several intermediates were determined. the pathway was inducible by l-arabinose, and two key enzymes, l-arabinose dehydrogenase and 2-keto-glutarate semialdehyde dehydrogenase, were present in all strains of h. seropedicae tested. | 1989 | 2768202 |
analgesic effectiveness of topically applied dynorphin on human dental pulp. | | 1986 | 2876436 |
isolation and mapping of a polymorphic dna sequence (prmu7.4) on chromosome 7p [d7s370]. | | 1988 | 2897660 |
the epidemiology of the acquired immunodeficiency syndrome. | | 1986 | 3008169 |
sequence of the genome ends and of the junction between the ends in concatemeric dna of pseudorabies virus. | the nucleotide sequences of the termini of the mature pseudorabies virus genome and of the junction between these termini in concatemeric dna were compared. to ensure conservation of unmodified 5' and 3' termini, the end fragments obtained directly (uncloned) from mature viral dna were sequenced. the sequence obtained from 5' and 3' end labeling revealed that whereas the l terminus was blunt ended, the s terminus had a 2-base (gg) 3' overhang. the sequences spanning the junction between the term ... | 1986 | 3023670 |
relationship between guanase activity in donor blood and the incidence of posttransfusional non-a, non-b hepatitis, and a possible method for preventing posttransfusional hepatitis. | a total of 107 recipients, who did not show any evidence of hepatic disorders in pretransfusional liver function tests and gave a negative reaction for hbsag, were observed from 3 weeks to 3 months after blood transfusion of 711 units of blood. the blood was judged suitable for use in transfusion because it had a normal level of alt activity and gave a negative reaction for hbsag. the guanase activities of the blood used for transfusion were examined. cases in which an increase of alt to at leas ... | 1986 | 3093359 |
non-immune igg f(ab')2 binding to group c and g streptococci is mediated by structures on gamma chains. | the present investigation was designed to determine whether the heavy or the light immunoglobulin chain is involved in the non-immune binding of igg f(ab')2 fragments to specific surface receptors on human group c and g streptococci. purified human polyclonal igg was mildly reduced with dithiothreitol and alkylated with iodoacetamide. light (l) and heavy (h) chains were separated. intact igg and purified l and h chains of polyclonal immunoglobulin g were tested in an inhibition assay for non-imm ... | 1985 | 3156400 |
regulation of haemonchus contortus populations in sheep: mortality of established worms. | | 1988 | 3372130 |
accumulation of kupffer cells within lymphocyte aggregates in the livers of chickens injected with colloidal carbon and erythrocytes. | | 1987 | 3500351 |
glycolysis in the mouse uterus during the early post-implantation stages of pregnancy and the effects of acute doses of ethanol. | the objective of this study was to assess the possibility that, in mice, alcohol interferes with uterine glycolysis to influence indirectly embryonal development. glycolysis was found to be a major metabolic process in the mouse uterus and its pattern of activity changed during post-implantation pregnancy between days 5 and 9. this was evidenced by changes in glycolytic enzymes and intermediates, and in the capacity of endometrial preparations to consume oxygen and produce lactate during incubat ... | 1987 | 3603401 |
induction of differentiation of the human leukemia cell line, ku812. | we treated ku812 cells from different passage levels with compounds which induce differentiation of other leukemic cell lines. early passages contained small subpopulations of basophil and erythrocyte-like cells, but later passages consisted of more uniform cells with a myelomonocytic phenotype. when cultured with 1 nm actinomycin d, the cells became nonproliferative, developed pale cytoplasm and segmented nuclei, and lost nonspecific esterase activity. thus, ku812 cells can be induced to mature ... | 1987 | 3695564 |
isolation and structure of antibiotic u-68,204, a new thiolactone. | a new thiolactone-containing antibiotic u-68,204 was found to be produced by a soil actinomycete identified as streptomyces thiolactonus uc 8478 (nrrl 15,439). the production, isolation, structure determination as well as the physical, spectroscopic and antibacterial properties of this c13h17no3s compound are here reported. on the basis of these data, the antibiotic was identified as the 10-carboxamide of thiotetromycin. | 1986 | 3753968 |
[factors determining the selectivity of cytochrome p-450-catalyzed alkane oxidation]. | hexane oxidation by various liver microsomes fractions of noninduced and phenobarbitol- or methylcholantrene-induced rabbits (mr, mrpb, mrmc) has been studied. the relative reactivity of the c-h bond at the 1st, 2nd and 3rd carbon atoms has been shown to depend on the fraction nature and on the oxygen-activating system (nadph/o2 or phio). the c3/c2 hexanol ratio is determined by steric factors of the hexane oxidation reaction. according to this parameter, the forms of cytochrome p-450 can be arr ... | 1986 | 3768443 |
comparison of histones in normal and xeroderma pigmentosum lymphoblastoid cells. | histones from normal human and xeroderma pigmentosum, complementation group a (xpa), lymphoblastoid cells were compared both quantitatively, qualitatively and for binding affinity for dna. electrophoretic examination of the histones showed that all five major histone species were present in both cell groups and that there were no quantitative differences between normal and xpa histones. binding affinity to [3h] mammalian dna of the histones was determined. no significant differences were observe ... | 1986 | 3791423 |
effect of piracetam on the electrocorticogram after traumatic brain oedema in cats. | the effect of piracetam on the electrocorticogram changes caused by experimentally-induced traumatic brain oedema in cats has been studied. the trauma was evoked by sticking a needle through the parietal associative cortical area. the electrocorticogram amplitude and frequency depression of the injured cortical area was eliminated and the bioelectrical activity restored to a normal pattern 22.4 +/- 10.3 min after a single dose of piracetam (100 mg/kg i.v.). the results indicate that piracetam re ... | 1985 | 3831634 |
oral cyclacillin interacts with the absorption of oral ampicillin, amoxycillin, and bacampicillin. | the relative bioavailabilities of single oral doses of ampicillin, amoxycillin, and bacampicillin were compared with and without concomitant administration of a six-times higher molar dose of cyclacillin. as the absorption of cyclacillin has been shown to involve a capacity-limited transport system in animals, it was selected as the reference compound for the study. the treatments were given to 14 fasting volunteers using a randomized, complete crossover design. the drugs in plasma and urine wer ... | 1985 | 3912193 |
multipotentiality of yolk-sac carcinoma cell clones. | yolk-sac carcinoma (ysca) clones were isolated by manual cloning under visual control. by morphology, immunohistology and histochemistry the clones were shown to differentiate in vitro into visceral and parietal yolk-sac cells and in vivo into visceral and parietal yolk-sac cells, trophoblast and mesenchyme. trophoblast and mesenchyme were only recorded in rat ysca derived from displaced yolk sac but not in embryo-derived ysca. hence ysca cells displaying a visceral and parietal yolk-sac pattern ... | 1985 | 4018906 |
synchrony between cortical neurons during operant conditioning. | one hundred twenty five pairs of neurons were recorded simultaneously from precentral cortex of macaca mulatta monkeys during an operant conditioning task. at the end of 5-min behavioral periods, a cross-correlation histogram was generated to look for relationships between the firing of the two cortical neurons. eighty four (67%) unit pairs showed a significant coincidence of firing within 1 ms of each other. this relationship occurred regardless of whether the units' firing rate fluctuations we ... | 1985 | 4041789 |
[malignant tumor of testicular gonadal stroma. treatment by combined chemotherapy-radiotherapy]. | the authors report the case of a 49-years-old man with an undifferentiated malignant gonadal stromal tumor of the right testis. malignancy is confirmed by metastasis in the retroperitoneal lymph nodes. after 6 courses of chemotherapy with cis-platinum, a retroperitoneal lymphadenectomy was performed and the section of the nodes showed a muscular differentiation of the tumor. this drug regimen did nod induce a complete response and an early recurrence occurs after lymphadenectomy which included t ... | 1985 | 4045207 |
in vivo and post mortem measurements of the attenuation spectra of light in mammalian tissues. | | 1985 | 4048297 |
[studies of assisted circulation. i. methods of repetitive provoked extrasystole and slowing of effective heart rate]. | | 1967 | 4166290 |
the histochemical properties of some periodate-reactive mucosubstances of the pregnant syrian hamster before and after methylation with methanolic thionyl chloride. | | 1967 | 4168055 |
animal models of allergic diseases. monkeys. | | 1970 | 4195743 |
the use of oxyphenbutazone ('tanderil') in acute pelvic inflammatory disease. | | 1973 | 4204087 |
typing of pseudomonas aeruginosa. | | 1973 | 4210814 |
[similarity of effects (static or dynamic) exercised by single fusimotor fibers on the primary endings of several spindles in the cat]. | | 1966 | 4222233 |
effect of high fat diets on acid mucopolysaccharides of the aorta in rabbits. | | 1970 | 4246453 |
[tissue adenosine triphosphatase activity of different sections of rat and rabbit brain in normal conditions and with administration of hydrocortisone]. | | 1973 | 4265282 |
renin in experimental "toxemia of pregnancy". | | 1967 | 4290942 |
renin in experimental "toxemia of pregnancy". | | 1967 | 4290942 |
[detection and identification of cholera vibrios, with special reference to rapid diagnosis and application of kappa-type phage]. | | 1971 | 4325092 |
[detection and identification of cholera vibrios, with special reference to rapid diagnosis and application of kappa-type phage]. | | 1971 | 4325092 |
trace constituents in milk fat: isolation and identification of oxofatty acids. | | 1974 | 4437320 |
structure-property relationships of the stratum corneum of human and neonatal rat. ii. dynamic mechanical studies. | | 1973 | 4710755 |
anterior cruciate ligament repair in cattle. | | 1971 | 4925718 |
studies on liver regeneration. ii. effects of phenobarbital on the onset and pattern of rat liver regeneration following partial hepatectomy. | | 1971 | 4947050 |
pulmonary absorption and retention of kanamycin after repeated inhalation administration of kanamycin aerosol. | the absorption and retention of kanamycin by the pulmonary system was evaluated after aerosol administration to rats. tissue level concentrations of the drug were assayed by the agar-plate bioassay method. mean concentrations of 6.58 mug/g and 3.52 mug/g were found in the lung and kidney homogenates, respectively, 26 hr after the final exposure period. no detectable level was found in the plasma. | 1970 | 4986727 |
cloning of a reca-like gene from the diazotroph herbaspirillum seropedicae strain z78. | a recombinant plasmid, pbmr5, carrying a reca-like gene of herbaspirillum seropedicae, was isolated from a h. seropedicae genomic library by intergeneric complementation of escherichia coli reca mutant strain hb101. quantitative survival experiments showed that pbmr5 restored the ultraviolet radiation and methyl methanesulfonate resistances and recombinational proficiency of this strain. hybridization studies showed that there is dna sequence homology between the reca gene of e. coli k12 and tha ... | 1993 | 8131107 |
emended description of herbaspirillum; inclusion of [pseudomonas] rubrisubalbicans, a milk plant pathogen, as herbaspirillum rubrisubalbicans comb. nov.; and classification of a group of clinical isolates (ef group 1) as herbaspirillum species 3. | [pseudomonas] rubrisubalbicans, a mild plant pathogen. herbaspirillum seropedicae, and ef group 1 strains (clustered by an immunological method) were investigated by a polyphasic approach with dna-rrna and dna-dna hybridizations and auxanography on 147 substrates. our results show that they all belong to the genus herbaspirillum. in addition to h. seropedicae, two other species are described: herbaspirillum rubrisubalbicans and a new unnamed species, herbaspirillum species 3, containing mainly s ... | 1996 | 8782693 |
specific flavonoids promote intercellular root colonization of arabidopsis thaliana by azorhizobium caulinodans ors571. | the ability of azorhizobium caulinodans ors571 and other diazotrophic bacteria to internally colonize roots of arabidopsis thaliana has been studied. strains tagged with lacz or gusa reporter genes were used, and the principal colonization sites were found to be the points of emergence of lateral roots, lateral root cracks (lrcs). high frequencies of colonization were found; 63 to 100% of plants were colonized by ors571, and 100% of plants were colonized by herbaspirillum seropedicae. after lrcs ... | 1997 | 9204562 |
cloning and sequencing of the nitrogenase structural genes nifhdk of herbaspirillum seropedicae. | the nitrogenase structural genes (nifhdk) of the endophytic diazotroph herbaspirillum seropedicae were isolated from a genomic bank by plate hybridization. sequence analysis of the dna showed a consensus promoter region upstream for the nifh gene containing a -24/-12 type promoter together with nifa- and integration host factor (ihf)- binding sites. the derived protein sequences of nifh, nifd and nifk contained conserved cysteine residues for binding iron-sulfur clusters and the iron-molybdenum ... | 1996 | 9222418 |
evidence for two possible glnb-type genes in herbaspirillum seropedicae. | two glnb-like genes have been isolated from herbaspirillum seropedicae by complementation of the klebsiella pneumoniae glnb502 mutant for growth on nitrate. one of these glnb-like genes has been sequenced and shows strong identity with glnb proteins derived from other organisms. a tn5-20 mutation of this glnb was nif negative. | 1997 | 9226275 |
control of herbaspirillum seropedicae nifa activity by ammonium ions and oxygen. | the activity of a truncated form of herbaspirillum seropedicae nifa in different genetic backgrounds showed that its regulatory domain is involved in nitrogen control but not in o2 sensitivity or fe dependence. the model for nitrogen control involving pii could thus apply to the proteobacteria at large. nifa may have a role in controlling adp-ribosylation of nitrogenase in azospirillum brasilense. | 1999 | 9882688 |
phylogenetic identification of two major nitrogen-fixing bacteria associated with sugarcane. | acetobacter diazotrophicus and herbaspirillum seropedicae were identified by genetic methods based on 16s rrna sequences. a specific pcr method in combination with probing was developed for a. diazotrophicus. the pcr system includes four primers, of which the primers named ac (ctgtttcccgcaagggac) and di (gcgccccattgctgggtt) generated an 445 bp amplicon in all of the 11 a. diazotrophicus strains tested. the phylogenetic position of h. seropedicae was determined. h. seropedicae forms with oxalobac ... | 1998 | 9924818 |
expression and functional analysis of an n-truncated nifa protein of herbaspirillum seropedicae. | in herbaspirillum seropedicae, an endophytic diazotroph, nif gene expression is under the control of the transcriptional activator nifa. we have over-expressed and purified a protein containing the central and c-terminal domains of the h. seropedicae nifa protein, n-truncated nifa, fused to a his-tag sequence. this fusion protein was found to be partially soluble and was purified by affinity chromatography. band shift and footprinting assays showed that the n-truncated nifa protein was able to b ... | 1999 | 10214962 |
anaerobic mineralization of quaternary carbon atoms: isolation of denitrifying bacteria on dimethylmalonate. | the microbial capacity to degrade simple organic compounds with quaternary carbon atoms was demonstrated by enrichment and isolation of five denitrifying strains on dimethylmalonate as the sole electron donor and carbon source. quantitative growth experiments showed a complete mineralization of dimethylmalonate. according to phylogenetic analysis of the complete 16s rrna genes, two strains isolated from activated sewage sludge were related to the genus paracoccus within the alpha-proteobacteria ... | 1999 | 10427013 |
in-trans regulation of the n-truncated-nifa protein of herbaspirillum seropedicae by the n-terminal domain. | the nifa protein is responsible for transcription activation of nif genes in the endophytic diazotroph herbaspirillum seropedicae. when expressed in escherichia coli this nifa protein is unable to activate the transcription of a klebsiella pneumoniae nifh::lacz fusion. however, a form of nifa lacking the n-terminal domain did activate transcription and its activity was not inhibited by ammonium. in this work we show that when expressed separately, the n-terminal domain of h. seropedicae nifa pro ... | 1999 | 10556706 |
sequencing and functional analysis of the nifenxorf1orf2 gene cluster of herbaspirillum seropedicae. | a 5.1-kb dna fragment from the nifhdk region of h. seropedicae was isolated and sequenced. sequence analysis showed the presence of nifenxorf1orf2 but nifty were not present. no nif or consensus promoter was identified. furthermore, orf1 expression occurred only under nitrogen-fixing conditions and no promoter activity was detected between nifk and nife, suggesting that these genes are expressed from the upstream nifh promoter and are parts of a unique nif operon. mutagenesis studies indicate th ... | 1999 | 10564803 |
two roles for integration host factor at an enhancer-dependent nifa promoter. | control of transcription in prokaryotes often involves direct contact of regulatory proteins with rna polymerase. for the sigma54 rna polymerase, regulatory proteins bound to distally located enhancers engage the polymerase via dna looping. the sigma54-dependent nifa promoter of herbaspirillum seropedicae (hs) is activated under nitrogen-limiting growth conditions. potential enhancers for the nitrogen control activators ntrc and nifa and binding sites for integration host factor (ihf) and sigma5 ... | 2000 | 10692153 |
expression of the nifa gene of herbaspirillum seropedicae: role of the ntrc and nifa binding sites and of the -24/-12 promoter element. | the nifa promoter of herbaspirillum seropedicae contains potential ntrc, nifa and ihf binding sites together with a -12/-24 sigma(n)-dependent promoter. this region has now been investigated by deletion mutagenesis for the effect of ntrc and nifa on the expression of a nifa::lacz fusion. a 5' end to the rna was identified at position 641, 12 bp downstream from the -12/-24 promoter. footprinting experiments showed that the g residues at positions -26 and -9 are hypermethylated, and that the regio ... | 2000 | 10846219 |
biocontrol of the sugarcane borer eldana saccharina by expression of the bacillus thuringiensis cry1ac7 and serratia marcescens chia genes in sugarcane-associated bacteria. | the cry1ac7 gene of bacillus thuringiensis strain 234, showing activity against the sugarcane borer eldana saccharina, was cloned under the control of the tac promoter. the fusion was introduced into the broad-host-range plasmid pkt240 and the integration vector pjff350 and without the tac promoter into the broad-host-range plasmids pml122 and pkmm0. these plasmids were introduced into a pseudomonas fluorescens strain isolated from the phylloplane of sugarcane and the endophytic bacterium herbas ... | 2000 | 10877771 |
azospirillum, a free-living nitrogen-fixing bacterium closely associated with grasses: genetic, biochemical and ecological aspects. | azospirillum represents the best characterized genus of plant growth-promoting rhizobacteria. other free-living diazotrophs repeatedly detected in association with plant roots, include acetobacter diazotrophicus, herbaspirillum seropedicae, azoarcus spp. and azotobacter. four aspects of the azospirillum-plant root interaction are highlighted: natural habitat, plant root interaction, nitrogen fixation and biosynthesis of plant growth hormones. each of these aspects is dealt with in a comparative ... | 2000 | 10978548 |
the transcriptional activator ntrc controls the expression and activity of glutamine synthetase in herbaspirillum seropedicae. | the role of the ntr system in herbaspirillum seropedicae was determined via ntrb and ntrc mutants. three phenotypes were identified in these mutants: nif(-), deficiency in growth using nitrate, and low glutamine synthetase (gs) activity. all phenotypes were restored by the plasmid pkrt1 containing the intact glna, ntrb and ntrc genes of h. seropedicae. the promoter region of glna was subcloned into a beta-galactosidase fusion vector and the results suggested that ntrc positively regulates the gl ... | 2000 | 11064198 |
use of lactose to induce expression of soluble nifa protein domains of herbaspirillum seropedicae in escherichia coli. | overexpression and purification are procedures used to allow functional and structural characterization of proteins. many overexpressed proteins are partially or completely insoluble, and can not be easily purified. the nifa protein is an enhancer-binding protein involved in activating the expression of nif and some fix genes. the nifa protein from many organisms is usually insoluble when over-expressed, and therefore difficult to work with in vitro. in this work we have overexpressed the centra ... | 2000 | 11109500 |
herbaspirillum frisingense sp. nov., a new nitrogen-fixing bacterial species that occurs in c4-fibre plants. | the enrichment of nitrogen-fixing bacteria from the c4-fibre plants, spartina pectinata, miscanthus sinensis, miscanthus sacchariflorus and pennisetum purpureum, with nitrogen-free semi-solid media led to the isolation of herbaspirillum-like strains among other diazotrophic bacteria. on the basis of physiological properties, phylogenetic analysis comparing 16s rdna sequences and dna-dna hybridization experiments of chromosomal dna the new isolates could be grouped together in a new species with ... | 2001 | 11211253 |
16s ribosomal dna characterization of nitrogen-fixing bacteria isolated from banana (musa spp.) and pineapple (ananas comosus (l.) merril). | nitrogen-fixing bacteria isolated from banana (musa spp.) and pineapple (ananas comosus (l.) merril) were characterized by amplified 16s ribosomal dna restriction analysis and 16s rrna sequence analysis. herbaspirillum seropedicae, herbaspirillum rubrisubalbicans, burkholderia brasilensis, and burkholderia tropicalis were identified. eight other types were placed in close proximity to these genera and other alpha and beta proteobacteria. | 2001 | 11319127 |
uridylylation of the pii protein from herbaspirillum seropedicae. | the pii protein is apparently involved in the control of nifa activity in herbaspirillum seropedicae. to evaluate the probable role of pii in signal transduction, uridylylation assays were conducted with purified h. seropedicae pii and escherichia coli glnd, or a cell-free extract of h. seropedicae as sources of uridylylating activity. the results showed that alpha-ketoglutarate and atp stimulate uridylylation whereas glutamine inhibits uridylylation. deuridylylation of pii-ump was dependent on ... | 2001 | 11358170 |
recent developments in the structural organization and regulation of nitrogen fixation genes in herbaspirillum seropedicae. | herbaspirillum seropedicae is a nitrogen-fixing bacterium found in association with economically important gramineae. regulation of nitrogen fixation involves the transcriptional activator nifa protein. the regulation of nifa protein and its truncated mutant proteins is described and compared with that of other nitrogen fixation bacteria. nitrogen fixation control in h. seropedicae, of the beta-subgroup of proteobacteria, has regulatory features in common with klebsiella pneumoniae, of the gamma ... | 2001 | 11566390 |
inter-domain cross-talk controls the nifa protein activity of herbaspirillum seropedicae. | herbaspirillum seropedicae is an endophytic diazotroph, which colonizes sugar cane, wheat, rice and maize. the activity of nifa, a transcriptional activator of nif genes in h. seropedicae, is controlled by ammonium ions through a mechanism involving its n-terminal domain. here we show that this domain interacts specifically in vitro with the n-truncated nifa protein, as revealed by protection against proteolysis, and this interaction caused an inhibitory effect on both the atpase and dna-binding ... | 2001 | 11707257 |
herbaspirillum seropedicae signal transduction protein pii is structurally similar to the enteric glnk. | pii-like proteins are signal transduction proteins found in bacteria, archaea and eukaryotes. they mediate a variety of cellular responses. a second pii-like protein, called glnk, has been found in several organisms. in the diazotroph herbaspirillum seropedicae, pii protein is involved in sensing nitrogen levels and controlling nitrogen fixation genes. in this work, the crystal structure of the unliganded h. seropedicae pii was solved by x-ray diffraction. h. seropedicae pii has a gly residue, g ... | 2002 | 12084071 |
control of autogenous activation of herbaspirillum seropedicae nifa promoter by the ihf protein. | analysis of the expression of the herbaspirillum seropedicae nifa promoter in escherichia coli and herbaspirillum seropedicae, showed that nifa expression is primarily dependent on ntrc but also required nifa for maximal expression under nitrogen-fixing conditions. deletion of the ihf (integration host factor)-binding site produced a promoter with two-fold higher activity than the native promoter in the h. seropedicae wild-type strain but not in a nifa strain, indicating that ihf controls nifa a ... | 2002 | 12113931 |
infection and colonization of rice seedlings by the plant growth-promoting bacterium herbaspirillum seropedicae z67. | a beta-glucoronidase (gus)-marked strain of herbaspirillum seropedicae z67 was inoculated onto rice seedling cvs. ir42 and ir72. internal populations peaked at over 10(6) log cfu per gram of fresh weight by 5 to 7 days after inoculation (dai) but declined to 10(3) to 10(4) log cfu per gram of fresh weight by 28 dai. gus staining was most intense on coleoptiles, lateral roots, and at the junctions of some of the main and lateral roots. bacteria entered the roots via cracks at the points of latera ... | 2002 | 12236596 |
expression, purification, and functional analysis of the c-terminal domain of herbaspirillum seropedicae nifa protein. | the herbaspirillum seropedicae nifa protein is responsible for nif gene expression. the c-terminal domain of the h. seropedicae nifa protein, fused to a his-tag sequence (his-tag-c-terminal), was over-expressed and purified by metal-affinity chromatography to yield a highly purified and active protein. band-shift assays showed that the nifa his-tag-c-terminal bound specifically to the h. seropedicae nifb promoter region in vitro. in vivo analysis showed that this protein inhibited the central + ... | 2003 | 12597891 |
fnr is involved in oxygen control of herbaspirillum seropedicae n-truncated nifa protein activity in escherichia coli. | herbaspirillum seropedicae is an endophytic diazotroph belonging to the beta-subclass of the class proteobacteria, which colonizes many members of the gramineae. the activity of the nifa protein, a transcriptional activator of nif genes in h. seropedicae, is controlled by ammonium ions through its n-terminal domain and by oxygen through mechanisms that are not well understood. here we report that the nifa protein of h. seropedicae is inactive and more susceptible to degradation in an fnr escheri ... | 2003 | 12620839 |
the recx gene product is involved in the sos response in herbaspirillum seropedicae. | the reca and the recx genes of herbaspirillum seropedicae were sequenced. the recx is located 359 bp downstream from reca. sequence analysis indicated the presence of a putative operator site overlapping a probable sigma70-dependent promoter upstream of reca and a transcription terminator downstream from recx, with no apparent promoter sequence in the intergenic region. transcriptional analysis using lacz promoter fusions indicated that reca expression increased three- to fourfold in the presenc ... | 2003 | 12718403 |
expression, purification, and dna-binding activity of the solubilized ntrc protein of herbaspirillum seropedicae. | ntrc is a bacterial enhancer-binding protein (ebp) that activates transcription by the sigma54 rna polymerase holoenzyme. ntrc has a three domain structure typical of ebp family. in herbaspirillum seropedicae, an endophytic diazotroph, ntrc regulates several operons involved in nitrogen assimilation, including glnantrbc. in order to over-express and purify the ntrc protein, dna fragments containing the complete structural gene for the whole protein, and for the n-terminal+central and central+c-t ... | 2003 | 12821329 |
nitrogenase activity of herbaspirillum seropedicae grown under low iron levels requires the products of nifxorf1 genes. | herbaspirillum seropedicae strains mutated in the nifx or orf1 genes showed 90% or 50% reduction in nitrogenase activity under low levels of iron or molybdenum respectively. mutations in nifx or orf1 genes did not affect nif gene expression since a nifh::lacz fusion was fully active in both mutants. nifx and the contiguous gene orf1 are essential for maximum nitrogen fixation under iron limitation and are probably involved in synthesis of nitrogenase iron or iron-molybdenum clusters. | 2003 | 12892890 |
significance of herbaspirillum seropedicae inoculation and/or straw amendment on growth and dinitrogen fixation of wheat using 15n-dilution method. | the effect of herbaspirillum seropedicae inoculation and/or maize straw (0, 5 and 10 mg/hm2) amendment on the growth and n2 fixation of wheat was determined in pot experiments using 15n-dilution method. inoculation resulted in accumulation of fixed nitrogen, and % n from atmosphere being 24.6 and 26.5% in wheat shoot and grain, respectively. straw amendment reduced % natm to 16.1 and 20.2% at high straw level (10 mg/hm2). rational nitrogen fertilization (180 kg n/hm2) completely inhibited n2 fix ... | 2003 | 15058193 |
expression, purification, and dna-binding activity of the herbaspirillum seropedicae recx protein. | the herbaspirillum seropedicae recx protein participates in the sos response: a process in which the reca protein plays a central role. the recx protein of the h. seropedicae, fused to a his-tag sequence (recx his-tagged), was over-expressed in escherichia coli and purified by metal-affinity chromatography to yield a highly purified and active protein. dna band-shift assays showed that the recx his-tagged protein bound to both circular and linear double-stranded dna and also to circular single-s ... | 2004 | 15135406 |
effect of t- and c-loop mutations on the herbaspirillum seropedicae glnb protein in nitrogen signalling. | proteins of the pii family are found in species of all kingdoms. although these proteins usually share high identity, their functions are specific to the different organisms. comparison of structural data from escherichia coli glnb and glnk and herbaspirillum seropedicae glnb showed that the t-loop and c-terminus were variable regions. to evaluate the role of these regions in signal transduction by the h. seropedicae glnb protein, four mutants were constructed: y51f, g108a/p109a, g108w and q3r/t ... | 2005 | 15950123 |
history on the biological nitrogen fixation research in graminaceous plants: special emphasis on the brazilian experience. | this review covers the history on biological nitrogen fixation (bnf) in graminaceous plants grown in brazil, and describes research progress made over the last 40 years, most of which was coordinated by johanna döbereiner. one notable accomplishment during this period was the discovery of several nitrogen-fixing bacteria such as the rhizospheric (beijerinckia fluminensis and azotobacter paspali), associative (azospirillum lipoferum, a. brasilense, a. amazonense) and the endophytic (herbaspirillu ... | 2005 | 16127558 |
characterization of the orf1glnkamtb operon of herbaspirillum seropedicae. | herbaspirillum seropedicae is an endophytic nitrogen-fixing bacterium that colonizes economically important grasses. in this organism, the amtb gene is co-transcribed with two other genes: glnk that codes for a pii-like protein and orf1 that codes for a probable periplasmatic protein of unknown function. the expression of the orf1glnkamtb operon is increased under nitrogen-limiting conditions and is dependent on ntrc. an amtb mutant failed to transport methylammonium. post-translational control ... | 2006 | 16331441 |
iron depletion affects nitrogenase activity and expression of nifh and nifa genes in herbaspirillum seropedicae. | herbaspirillum seropedicae z67 is a nitrogen-fixing bacterium able to colonize the rhizosphere and the interior of several plants. as iron is a key element for nitrogen fixation, we examined the response of this microorganism to iron deficiency under nitrogen fixing conditions. we identified a h. seropedicae exbd gene that was induced in response to iron limitation and is involved in iron homeostasis. we found that an exbd mutant grown in iron-chelated medium is unable to fix nitrogen. moreover, ... | 2006 | 16640576 |
adsorption of protein glnb of herbaspirillum seropedicae on si(111) investigated by afm and xps. | the protein glnb-hs (glnb of herbaspirillum seropedicae) in diazotroph micro-organisms signalizes levels of nitrogen, carbon, and energy for a series of proteins involved in the regulation of expression and control of the activity of nitrogenase complex that converts atmospheric nitrogen in ammonia, resulting in biological nitrogen fixation. its structure has already been determined by x-ray diffraction, revealing a trimer of (36 kda) with lateral cavities having hydrophilic boundaries. the inte ... | 2006 | 16679538 |
expression, purification and biochemical characterization of a single-stranded dna binding protein from herbaspirillum seropedicae. | an open reading frame encoding a protein similar in size and sequence to the escherichia coli single-stranded dna binding protein (ssb protein) was identified in the herbaspirillum seropedicae genome. this open reading frame was cloned into the expression plasmid pet14b. the ssb protein from h. seropedicae, named hs_ssb, was overexpressed in e. coli strain bl21(de3) and purified to homogeneity. mass spectrometry data confirmed the identity of this protein. the apparent molecular mass of the nati ... | 2007 | 17223357 |
identification of nh4+-regulated genes of herbaspirillum seropedicae by random insertional mutagenesis. | random mutagenesis using transposons with promoterless reporter genes has been widely used to examine differential gene expression patterns in bacteria. using this approach, we have identified 26 genes of the endophytic nitrogen-fixing bacterium herbaspirillum seropedicae regulated in response to ammonium content in the growth medium. these include nine genes involved in the transport of nitrogen compounds, such as the high-affinity ammonium transporter amtb, and uptake systems for alternative n ... | 2007 | 17323064 |
effects of the inoculation of burkholderia vietnamensis and related endophytic diazotrophic bacteria on grain yield of rice. | during a survey of endophytic diazotrophic bacteria associated with different rice varieties in tamilnadu, some "endophytes" were obtained. thirteen bacterial isolates from surface-sterilized roots and shoots were obtained in pure culture, which produced indole acetic acid (iaa) and reduced acetylene to ethylene. polymerase chain reaction (pcr) amplification confirmed the presence of nif-h gene in all the isolates. morphological, biochemical, and molecular characteristics indicated that all of t ... | 2008 | 17406771 |