Publications
| Title | Abstract | Year Filter | PMID(sorted descending) Filter |
|---|
| evaluation of antitumor activity of some medicinal plants of bangladesh by potato disk bioassay. | the antitumor activity of the ethanolic extracts of 12 medicinal plants of bangladesh, including the vincristine-vinblastine producing catharanthus roseus was studied using the potato disk bioassay technique. among these, 10 plant extracts at 25.0-microgram/disc exhibited significant inhibition of crown gall tumors caused by agrobacterium tumefaciens. | 2000 | 11449504 |
| rerouting the plant phenylpropanoid pathway by expression of a novel bacterial enoyl-coa hydratase/lyase enzyme function. | the gene for a bacterial enoyl-coa hydratase (crotonase) homolog (hchl) previously shown to convert 4-coumaroyl-coa, caffeoyl-coa, and feruloyl-coa to the corresponding hydroxybenzaldehydes in vitro provided an opportunity to subvert the plant phenylpropanoid pathway and channel carbon flux through 4-hydroxybenzaldehyde and the important flavor compound 4-hydroxy-3-methoxybenzaldehyde (vanillin). expression of the pseudomonas fluorescens an103 hchl gene in two generations of tobacco plants cause ... | 2001 | 11449058 |
| functional analysis of cyclin-dependent kinase inhibitors of arabidopsis. | cyclin-dependent kinase inhibitors, such as the mammalian p27(kip1) protein, regulate correct cell cycle progression and the integration of developmental signals with the core cell cycle machinery. these inhibitors have been described in plants, but their function remains unresolved. we have isolated seven genes from arabidopsis that encode proteins with distant sequence homology with p27(kip1), designated kip-related proteins (krps). the krps were characterized by their domain organization and ... | 2001 | 11449057 |
| overexpression of the heterotrimeric g-protein alpha-subunit enhances phytochrome-mediated inhibition of hypocotyl elongation in arabidopsis. | plant heterotrimeric g-proteins have been implicated in a number of signaling processes. however, most of these studies are based on biochemical or pharmacological approaches. to examine the role of heterotrimeric g-proteins in plant development, we generated transgenic arabidopsis expressing the galpha subunit of the heterotrimeric g-protein under the control of a glucocorticoid-inducible promoter. with the conditional overexpression of either the wild type or a constitutively active version of ... | 2001 | 11449056 |
| arabidopsis alf5, a multidrug efflux transporter gene family member, confers resistance to toxins. | the arabidopsis genome contains many gene families that are not found in the animal kingdom. one of these is the multidrug and toxic compound extrusion (mate) family, which has homology with bacterial efflux transporters. arabidopsis has at least 54 members of this family, which often are found in tandem repeats. analysis of alf5, one member of this arabidopsis family, suggests that its function is required for protection of the roots from inhibitory compounds. loss of alf5 function results in t ... | 2001 | 11449055 |
| repressing a repressor: gibberellin-induced rapid reduction of the rga protein in arabidopsis. | rga (for repressor of ga1-3) and spindly (spy) are likely repressors of gibberellin (ga) signaling in arabidopsis because the recessive rga and spy mutations partially suppressed the phenotype of the ga-deficient mutant ga1-3. we found that neither rga nor spy altered the ga levels in the wild-type or the ga1-3 background. however, expression of the ga biosynthetic gene ga4 was reduced 26% by the rga mutation, suggesting that partial derepression of the ga response pathway by rga resulted in the ... | 2001 | 11449051 |
| one plant actin isovariant, act7, is induced by auxin and required for normal callus formation. | during plant growth and development, the phytohormone auxin induces a wide array of changes that include cell division, cell expansion, cell differentiation, and organ initiation. it has been suggested that the actin cytoskeleton plays an active role in the elaboration of these responses by directing specific changes in cell morphology and cytoarchitecture. here we demonstrate that the promoter and the protein product of one of the arabidopsis vegetative actin genes, act7, are rapidly and strong ... | 2001 | 11449050 |
| agrobacterium tumefaciens-mediated genetic transformation of mungbean (vigna radiata l. wilczek) - a recalcitrant grain legume. | agrobacterium-mediated transformation of vigna radiata l. wilczek has been achieved. hypocotyl and primary leaves excised from 2-day-old in-vitro grown seedlings produced transgenic calli on b(5) basal medium supplemented with 5x10(-6) m bap, 2.5x10(-6) m each of 2,4-d and naa and 50 mg l(-1) kanamycin after co-cultivation with agrobacterium tumefaciens strains, lba4404 (ptok233), eha105 (pbin9gusint) and c58c1 (pig121hm) all containing beta-glucuronidase (gusa) and neomycin phosphotransferase i ... | 2001 | 11448754 |
| isolation of a flax pectin methylesterase promoter and its expression in transgenic tobacco. | pectin methylesterases (pme) catalyze the de-esterification of methoxylated pectins in plant cell walls. we have isolated a 1.9 kb regulatory region upstream from the lupme3 coding sequence of linum usitatissimum l. (flax) using a 'polymerase chain reaction (pcr) walking' strategy. two 5' truncated deletion fragments (1.5 and 0.44 kb) of this potential promoter sequence were inserted upstream of the gus reporter gene in order to study their expression in transgenic plants. these constructs were ... | 2001 | 11448746 |
| effects of ipt gene expression on the physiological and chemical characteristics of artemisia annua l. | an isopentenyl transferase gene (ipt) from t-dna was transferred into artemisia annua l. via agrobacterium tumefaciens. the ipt gene was placed in a binary vector under the control of the camv 35s promoter. leaf explants were infected with a. tumefaciens lba4404 containing pbiipt to induce the buds. nineteen shoot lines were selected, which were resistant to kanamycin. polymerase chain reactions and southern blotting confirmed that at least five shoot lines contained the foreign gene. the result ... | 2001 | 11448744 |
| potential virulence role of the legionella pneumophila ptsp ortholog. | we previously identified the legionella pneumophila ptsp (phosphoenolpyruvate phosphotransferase) ortholog gene as a putative virulence factor in a study of signature-tagged mutagenesis using a guinea pig pneumonia model. in this study, we further defined the phenotypic properties of l. pneumophila ptsp and its complete sequence. the l. pneumophila ptsp was 2,295 bases in length. its deduced amino acid sequence had high similarity with ptsp orthologs of pseudomonas aeruginosa, azotobacter vinela ... | 2001 | 11447151 |
| production of n-acyl homoserine lactones by gram-negative bacteria isolated from contact lens wearers. | the purpose of this study was to investigate the production of n-acyl-homoserine lactone (ahl) signal molecules in ocular gram-negative bacteria. a total of 91 ocular strains isolated from contact lens adverse response patients and asymptomatic subjects were used in the study. these included acinetobacter, aeromonas hydrophila, escherichia coli, haemophilus influenzae, klebsiella oxytoca, pseudomonas aeruginosa, serratia liquefaciens, serratia marcescens, and stenotrophomonas maltophilia. the bi ... | 2001 | 11446456 |
| [use of highly dispersed materials for culturing and isolation of granular agrobacterium radiobacter preparations ]. | the effects of synthetic and natural high-dispersion materials on the growth of agrobacterium radiobacter were studied. natural minerals montmorillonite and palygorskite (10 g/l nutrient medium) were more potent than high-dispersion silica and its modified forms in stimulating growth of agrobacterium radiobacter. the interaction of agrobacterium radiobacter with clay minerals increased the survival rate of bacteria at supraoptimal temperatures. we elaborated new granular bacterial preparation, w ... | 2001 | 11443910 |
| [isolation of genetically modified potato plant containing the gene of defensive peptide from amaranthus]. | the plants of potato (solanum tuberosum l., var. desire) have been transformed with a ph22kneo vector carrying the gene ac2, encoding the fungicidal peptide (defensin) from the seed of amaranth (amaranthus caudatus l.). the transformation involved co-cultivation of potato stem explants (excised from aseptically grown plants) and agrobacterium tumefaciens on solid ms medium. factors affecting in vitro regeneration of the explants and the transformation efficiency were optimized. regenerated potat ... | 2001 | 11443906 |
| old yellow enzyme: reduction of nitrate esters, glycerin trinitrate, and propylene 1,2-dinitrate. | the reaction of the old yellow enzyme and reduced flavins with organic nitrate esters has been studied. reduced flavins have been found to react readily with glycerin trinitrate (gtn ) (nitroglycerin) and propylene dinitrate, with rate constants at ph 7.0, 25 degrees c of 145 m(-1)s(-1) and 5.8 m(-1)s(-1), respectively. with gtn, the secondary nitrate was removed reductively 6 times faster than the primary nitrate, with liberation of nitrite. with propylene dinitrate, on the other hand, the prim ... | 2001 | 11438708 |
| cloning and functional analysis of two gibberellin 3 beta -hydroxylase genes that are differently expressed during the growth of rice. | we have cloned two gibberellin (ga) 3 beta-hydroxylase genes, osga3ox1 and osga3ox2, from rice by screening a genomic library with a dna fragment obtained by pcr using degenerate primers. we have used full-scan gc-ms and kovats retention indices to show function for the two encoded recombinant fusion proteins. both proteins show 3 beta-hydroxylase activity for the steps ga(20) to ga(1), ga(5) to ga(3), ga(44) to ga(38), and ga(9) to ga(4). in addition, indirect evidence suggests that the osga3ox ... | 2001 | 11438692 |
| molecular characterization of transgenic shallots (allium cepa l.) by adaptor ligation pcr (al-pcr) and sequencing of genomic dna flanking t-dna borders. | genomic dna blot hybridization is traditionally used to demonstrate that, via genetic transformation, foreign genes are integrated into host genomes. however, in large genome species, such as allium cepa l., the use of genomic dna blot hybridization is pushed towards its limits, because a considerable quantity of dna is needed to obtain enough genome copies for a clear hybridization pattern. furthermore, genomic dna blot hybridization is a time-consuming method. adaptor ligation pcr (al-pcr) of ... | 2001 | 11437280 |
| the transposition pattern of the ac element in tobacco cultured cells. | we investigated physical distances and directions of transposition of the maize transposable element ac in tobacco cultured cells. we introduced a t-dna construct that carried a non-autonomous derivative of ac (designated dac-i-rs) that included sites for cleavage by restriction endonuclease mlui. another cleavage site was also introduced into the t-dna region outside of the dac-i-rs transposable element. the tobacco cultured cell line by-2 was transformed with the t-dna and several transformed ... | 2001 | 11434458 |
| sequence characterization of the vir region of a nopaline type ti plasmid, pti-sakura. | we isolated a crown gall tumor-inducing nopaline type ti plasmid from agrobacterium tumefaciens on a sakura japanese cherry tree, and designated it as pti-sakura. by primer walking sequencing with long pcr and a newly developed pcr subcloning technique for long insert dna, we completed dna sequencing of the most important functional unit, the virulence (vir) region of pti-sakura, which is indispensable for t-dna transfer into the plant's chromosomes. by homology searches with the vir genes of ot ... | 2001 | 11434457 |
| highly enantioselective and regioselective biocatalytic azidolysis of aromatic epoxides. | [figure: see text] the halohydrin dehalogenase from agrobacterium radiobacter ad1 catalyzed the highly enantioselective and beta-regioselective azidolysis of (substituted) styrene oxides. by means of kinetic resolutions the remaining epoxide and the formed azido alcohol could be obtained in very high ee. in a large scale conversion, the decrease in yield and selectivity due to the uncatalyzed chemical side reaction could be overcome by slow addition of azide. | 2001 | 11429866 |
| genetic and biochemical characterization of an enantioselective amidase from agrobacterium tumefaciens strain d3. | an enantioselective amidase was purified to homogeneity from agrobacterium tumefaciens d3. the enzyme has a molecular mass of about 490000 da and is composed of identical subunits with a molecular mass of about 63000 da. the purified enzyme converted racemic 2-phenylpropionamide to the corresponding s-acid with an enantiomeric excess (ee) value >95% at almost 50% conversion of the racemic amide. the purified enzyme was digested with trypsin and the amino acid sequences of the n terminus and diff ... | 2001 | 11429459 |
| metabolic engineering of essential oil yield and composition in mint by altering expression of deoxyxylulose phosphate reductoisomerase and menthofuran synthase. | peppermint (mentha x piperita l.) was independently transformed with a homologous sense version of the 1-deoxy-d-xylulose-5-phosphate reductoisomerase cdna and with a homologous antisense version of the menthofuran synthase cdna, both driven by the camv 35s promoter. two groups of transgenic plants were regenerated in the reductoisomerase experiments, one of which remained normal in appearance and development; another was deficient in chlorophyll production and grew slowly. transgenic plants of ... | 2001 | 11427737 |
| nitrogen-fixing nodules with ensifer adhaerens harboring rhizobium tropici symbiotic plasmids. | ensifer adhaerens is a soil bacterium that attaches to other bacteria and may cause lysis of these other bacteria. based on the sequence of its small-subunit rrna gene, e. adhaerens is related to sinorhizobium spp. e. adhaerens atcc 33499 did not nodulate phaseolus vulgaris (bean) or leucaena leucocephala, but with symbiotic plasmids from rhizobium tropici cfn299 it formed nitrogen-fixing nodules on both hosts. the nodule isolates were identified as e. adhaerens isolates by growth on selective m ... | 2001 | 11425750 |
| reaction of acylated homoserine lactone bacterial signaling molecules with oxidized halogen antimicrobials. | oxidized halogen antimicrobials, such as hypochlorous and hypobromous acids, have been used extensively for microbial control in industrial systems. recent discoveries have shown that acylated homoserine lactone cell-to-cell signaling molecules are important for biofilm formation in pseudomonas aeruginosa, suggesting that biofouling can be controlled by interfering with bacterial cell-to-cell communication. this study was conducted to investigate the potential for oxidized halogens to react with ... | 2001 | 11425738 |
| quorum sensing in the dimorphic fungus candida albicans is mediated by farnesol. | the inoculum size effect in the dimorphic fungus candida albicans results from production of an extracellular quorum-sensing molecule (qsm). this molecule prevents mycelial development in both a growth morphology assay and a differentiation assay using three chemically distinct triggers for germ tube formation (gtf): l-proline, n-acetylglucosamine, and serum (either pig or fetal bovine). in all cases, the presence of qsm prevents the yeast-to-mycelium conversion, resulting in actively budding ye ... | 2001 | 11425711 |
| the functional ccpa gene is required for carbon catabolite repression in lactobacillus plantarum. | we report the characterization of the ccpa gene of lactobacillus plantarum, coding for catabolite control protein a. the gene is linked to the pepq gene, encoding a proline peptidase, in the order ccpa-pepq, with the two genes transcribed in tandem from the same strand as distinct transcriptional units. two ccpa transcription start sites corresponding to two functional promoters were found, expression from the upstream promoter being autogenously regulated through a catabolite-responsive element ... | 2001 | 11425700 |
| [ability of representatives of pantoea agglomerans, as well as bacillus subtilis and some pseudomonas species to suppress the development of phytopathgenic bacteria and micromycetes in regulating plant growth]. | the ability of representatives of pantoea agglomerans (erwinia herbicola (lohnis) dye [21]), bacillus subtilis and some species of pseudomonas genus to inhibit the growth of phytopathogenic bacteria and micromycetes and to regulate the growth of plants has been comparatively studied. the ability to inhibit the growth of mycellium of phytopathogenic fusarium avenaceum, f. gibbosum, f. oxysporum was found out in all of 13 investigated strains of p. agglomerans, while the growth of f. culmorum is i ... | 2000 | 11421000 |
| structural and functional characterization of is679 and is66-family elements. | a new insertion sequence (is) element, is679 (2,704 bp in length), has been identified in plasmid pb171 of enteropathogenic escherichia coli b171. is679 has imperfect 25-bp terminal inverted repeats (irs) and three open reading frames (orfs) (here called tnpa, tnpb, and tnpc). a plasmid carrying a composite transposon (tn679) with the kanamycin resistance gene flanked by an intact is679 sequence and an is679 fragment with only irr (ir on the right) was constructed to clarify the transposition ac ... | 2001 | 11418571 |
| accumulation of the phap phasin of ralstonia eutropha is dependent on production of polyhydroxybutyrate in cells. | polyhydroxyalkanoates (phas) are polyoxoesters that are produced by diverse bacteria and that accumulate as intracellular granules. phasins are granule-associated proteins that accumulate to high levels in strains that are producing phas. the accumulation of phasins has been proposed to be dependent on pha production, a model which is now rigorously tested for the phasin phap of ralstonia eutropha. r. eutropha phac pha synthase and phap phasin gene replacement strains were constructed. the strai ... | 2001 | 11418562 |
| indole can act as an extracellular signal in escherichia coli. | previous work has shown that lacz fusions to the cysk, astd, tnab, and gabt genes in escherichia coli are activated by self-produced extracellular signals. using a combination of ethyl acetate extraction, reversed-phase c(18) chromatography, and thin-layer chromatography, we have purified an extracellular activating signal from e. coli supernatants. mass spectrometry revealed a molecule with an m/z peak of 117, consistent with indole. nuclear magnetic resonance analysis of the purified e. coli f ... | 2001 | 11418561 |
| role of the 3'-untranslated regions of alfalfa mosaic virus rnas in the formation of a transiently expressed replicase in plants and in the assembly of virions. | alfalfa mosaic virus (amv) rnas 1 and 2 encode the replicase proteins p1 and p2, respectively, whereas rna 3 encodes the movement protein and the coat protein (cp). when rnas 1 and 2 were transiently expressed from a t-dna vector (r12 construct) by agroinfiltration of nicotiana benthamiana, the infiltrated leaves accumulated minus-strand rnas 1 and 2 and relatively small amounts of plus-strand rnas. in addition, rna-dependent rna polymerase (rdrp) activity could be detected in extracts of the in ... | 2001 | 11413311 |
| control of axillary bud initiation and shoot architecture in arabidopsis through the supershoot gene. | the aerial architecture of flowering plants is determined to a large extent by shoot growth and shoot branching arising from the initiation and growth of axillary meristems. we have identified an arabidopsis mutant, supershoot (sps), which is characterized by a massive overproliferation of shoots, such that a single plant can generate 500 or more inflorescences. analysis of the mutant plants shows that the primary defect is because of an increase in the number of meristems formed in leaf axils, ... | 2001 | 11410537 |
| characterization and sequence analysis of the replicator region of the novel plasmid palc1 from paracoccus alcaliphilus. | the replicator region of a low-copy-number plasmid, palc1, of paracoccus alcaliphilus jcm 7364 was cloned in a form of the minireplicon palc100 (3.6 kb). the host range of the minireplicon embraces several species of genus paracoccus, as well as agrobacterium tumefaciens, rhizobium leguminosarum, and rhodobacter sphaeroides (all belonging to alpha-proteobacteria), but not escherichia coli. the complete nucleotide sequence of the replicator region (2276 bp) revealed the presence of one complete o ... | 2001 | 11407917 |
| characterization of a putative rnd-type efflux system in agrobacterium tumefaciens. | sequencing of a 7277 bp fragment adjacent to the chvh locus of agrobacterium tumefaciens revealed four open reading frames (orfs), designated amer, amea, ameb and amec, respectively. these orfs exhibit amino acid similarities to components of resistance-nodulation-cell division (rnd) type efflux systems. amea and ameb show high homology to membrane fusion proteins (mfp) and rnd-type transporters, whereas amec shows similarity to nodt and other members of outer membrane factor families. mutations ... | 2001 | 11404022 |
| seed-specific over-expression of an arabidopsis cdna encoding a diacylglycerol acyltransferase enhances seed oil content and seed weight. | we recently reported the cloning and characterization of an arabidopsis (ecotype columbia) diacylglycerol acyltransferase cdna (zou et al., 1999) and found that in arabidopsis mutant line as11, an ethyl methanesulfonate-induced mutation at a locus on chromosome ii designated as tag1 consists of a 147-bp insertion in the dna, which results in a repeat of the 81-bp exon 2 in the tag1 cdna. this insertion mutation is correlated with an altered seed fatty acid composition, reduced diacylglycerol acy ... | 2001 | 11402213 |
| molecular characterization of at5ptase1, an inositol phosphatase capable of terminating inositol trisphosphate signaling. | the inositol triphosphate (ip(3))-signaling pathway has been associated with several developmental and physiological processes in plants, but we currently know little about the regulation of this pathway. inositol 5' phosphatases (5ptases) are enzymes that remove a 5' phosphate from several potential second messengers, including ip(3). in catalyzing the removal of a 5' phosphate from second messenger substrates, 5ptases can act to terminate signal transduction events. we describe the molecular a ... | 2001 | 11402208 |
| transgenic arabidopsis plants with decreased activity of fructose-6-phosphate,2-kinase/fructose-2,6-bisphosphatase have altered carbon partitioning. | the role of fructose-2,6-bisphosphate (fru-2,6-p(2)) as a regulatory metabolite in photosynthetic carbohydrate metabolism was studied in transgenic arabidopsis plants with reduced activity of fru-6-phosphate,2-kinase/fru-2,6-bisphosphatase. a positive correlation was observed between the fru-6-phosphate,2-kinase activity and the level of fru-2,6-p(2) in the leaves. the partitioning of carbon was studied by (14)co(2) labeling of photosynthetic products. plant lines with fru-2,6-p(2) levels down t ... | 2001 | 11402203 |
| the arabidopsis embryo mutant schlepperless has a defect in the chaperonin-60alpha gene. | we identified a t-dna-generated mutation in the chaperonin-60alpha gene of arabidopsis that produces a defect in embryo development. the mutation, termed schlepperless (slp), causes retardation of embryo development before the heart stage, even though embryo morphology remains normal. beyond the heart stage, the slp mutation results in defective embryos with highly reduced cotyledons. slp embryos exhibit a normal apical-basal pattern and radial tissue organization, but they are morphologically r ... | 2001 | 11402200 |
| the rop gtpase switch controls multiple developmental processes in arabidopsis. | g proteins are universal molecular switches in eukaryotic signal transduction. the arabidopsis genome sequence reveals no ras small gtpase and only one or a few heterotrimeric g proteins, two predominant classes of signaling g proteins found in animals. in contrast, arabidopsis possesses a unique family of 11 rop gtpases that belong to the rho family of small gtpases. previous studies indicate that rop controls actin-dependent pollen tube growth and h(2)o(2)-dependent defense responses. in this ... | 2001 | 11402196 |
| the heme-oxygenase family required for phytochrome chromophore biosynthesis is necessary for proper photomorphogenesis in higher plants. | the committed step in the biosynthesis of the phytochrome chromophore phytochromobilin involves the oxidative cleavage of heme by a heme oxygenase (ho) to form biliverdin ixalpha. through positional cloning of the photomorphogenic mutant hy1, the arabidopsis ho (designated atho1) responsible for much of phytochromobilin synthesis recently was identified. using the atho1 sequence, we identified families of ho genes in a number of plants that cluster into two subfamilies (ho1- and ho2-like). the t ... | 2001 | 11402195 |
| the arabidopsis athb-8 hd-zip protein acts as a differentiation-promoting transcription factor of the vascular meristems. | athb-8, -9, -14, -15, and ifl1/rev are members of a small homeodomain-leucine zipper family whose genes are characterized by expression in the vascular tissue. athb-8, a gene positively regulated by auxin (baima et al., 1995), is considered an early marker of the procambial cells and of the cambium during vascular regeneration after wounding. here, we demonstrate that although the formation of the vascular system is not affected in athb8 mutants, ectopic expression of athb-8 in arabidopsis plant ... | 2001 | 11402194 |
| the mitochondrial isovaleryl-coenzyme a dehydrogenase of arabidopsis oxidizes intermediates of leucine and valine catabolism. | we recently identified a cdna encoding a putative isovaleryl-coenzyme a (coa) dehydrogenase in arabidopsis (ativd). in animals, this homotetrameric enzyme is located in mitochondria and catalyzes the conversion of isovaleryl-coa to 3-methylcrotonyl-coa as an intermediate step in the leucine (leu) catabolic pathway. expression of ativd:smgfp4 fusion proteins in tobacco (nicotiana tabacum) protoplasts and biochemical studies now demonstrate the in vivo import of the plant isovaleryl-coa dehydrogen ... | 2001 | 11402190 |
| atcsld3, a cellulose synthase-like gene important for root hair growth in arabidopsis. | a member of the cellulose synthase-like (subfamily d) gene family of arabidopsis, atcsld3, has been identified by t-dna tagging. the analysis of the corresponding mutant, csld3-1, showed that the atcsld3 gene plays a role in root hair growth in plants. root hairs grow in phases: first a bulge is formed and then the root hair elongates by polarized growth, the so-called "tip growth." in the mutant, root hairs were initiated at the correct position and grew into a bulge, but their elongation was s ... | 2001 | 11402188 |
| the biological functions of glutathione revisited in arabidopsis transgenic plants with altered glutathione levels. | a functional analysis of the role of glutathione in protecting plants from environmental stress was undertaken by studying arabidopsis that had been genetically modified to have altered glutathione levels. the steady-state glutathione concentration in arabidopsis plants was modified by expressing the cdna for gamma-glutamyl-cysteine synthetase (gsh1) in both the sense and antisense orientation. the resulting plants had glutathione levels that ranged between 3% and 200% of the level in wild-type ... | 2001 | 11402187 |
| proliferating cell nuclear antigen transcription is repressed through an e2f consensus element and activated by geminivirus infection in mature leaves. | the geminivirus tomato golden mosaic virus (tgmv) amplifies its dna genome in differentiated plant cells that lack detectable levels of dna replication enzymes. earlier studies showed that tgmv induces the accumulation of proliferating cell nuclear antigen (pcna), the processivity factor for dna polymerase delta, in mature cells of nicotiana benthamiana. we sought to determine if pcna protein accumulation reflects transcriptional activation of the host gene. rna gel blot analysis detected an app ... | 2001 | 11402171 |
| fpa, a gene involved in floral induction in arabidopsis, encodes a protein containing rna-recognition motifs. | fpa is a gene that regulates flowering time in arabidopsis via a pathway that is independent of daylength (the autonomous pathway). mutations in fpa result in extremely delayed flowering. fpa was identified by means of positional cloning. the predicted fpa protein contains three rna recognition motifs in the n-terminal region. fpa is expressed most strongly in developing tissues, similar to the expression of fca and luminidependens, two components of the autonomous pathway previously identified. ... | 2001 | 11402170 |
| a clock- and light-regulated gene that links the circadian oscillator to lhcb gene expression. | we have identified and characterized a novel tobacco gene, called zgt (from the chinese phrase zhong guang tiaokong, or clock and light controlled), that is regulated by the circadian clock and light. zgt transcripts have alternate forms that are differentially expressed in different tissues. zgt is expressed rhythmically in light/dark cycles and in constant light. constitutive expression of zgt sustains the expression of the clock-controlled lhcb1*1 gene in constant darkness, when it would norm ... | 2001 | 11402169 |
| production of 6-methylsalicylic acid by expression of a fungal polyketide synthase activates disease resistance in tobacco. | salicylic acid (sa) has been shown to act as a signal molecule that is produced by many plants subsequent to the recognition of potentially pathogenic microbes. increases in levels of sa often trigger the activation of plant defenses and can result in increased resistance to subsequent challenge by pathogens. we observed that the polyketide 6-methylsalicylic acid (6-mesa), a compound that apparently is not endogenous to tobacco, can mimic sa. tobacco leaves treated with 6-mesa show enhanced accu ... | 2001 | 11402168 |
| adf proteins are involved in the control of flowering and regulate f-actin organization, cell expansion, and organ growth in arabidopsis. | based mostly on the results of in vitro experiments, adf (actin-depolymerizing factor) proteins are thought to be key modulators of the dynamic organization of the actin cytoskeleton. the few studies concerned with the in vivo function of adf proteins that have been reported to date were performed almost exclusively using single-cell systems and have failed to produce consistent results. to investigate adf functions in vivo and during the development of multicellular organs, we generated transge ... | 2001 | 11402164 |
| antisense expression of a cell wall-associated protein kinase, wak4, inhibits cell elongation and alters morphology. | the arabidopsis cell wall-associated receptor-like kinase (wak) gene family contains five highly related members whose products are suited for exchanging signals between the intracellular and extracellular compartments. wak members are expressed in specific organs and regulated differentially by various biotic and abiotic factors. to gain further insight into how waks function during development, we used a glucocorticoid-inducible system to express ectopically the wak4 antisense gene. the induce ... | 2001 | 11402163 |
| elf3 modulates resetting of the circadian clock in arabidopsis. | the arabidopsis early flowering 3 (elf3) mutation causes arrhythmic circadian output in continuous light, but there is some evidence of clock function in darkness. here, we show conclusively that normal circadian function occurs with no alteration of period length in elf3 mutants in dark conditions and that the light-dependent arrhythmia observed in elf3 mutants is pleiotropic on multiple outputs normally expressed at different times of day. plants overexpressing elf3 have an increased period le ... | 2001 | 11402162 |
| early flowering3 encodes a novel protein that regulates circadian clock function and flowering in arabidopsis. | higher plants use photoperiodic cues to regulate many aspects of development, including the transition from vegetative to floral development. the early flowering3 (elf3) gene is required for photoperiodic flowering and normal circadian regulation in arabidopsis. we have cloned elf3 by positional methods and found that it encodes a novel 695-amino acid protein that may function as a transcriptional regulator. elf3 transcript level is regulated in a circadian manner, as is expected of a zeitnehmer ... | 2001 | 11402160 |
| an evolutionist visits the 43rd annual maize genetics conference. | 2001 | 11402157 | |
| distribution of quorum-sensing genes in the burkholderia cepacia complex. | the distribution of quorum-sensing genes among strains from seven genomovars of the burkholderia cepacia complex was examined by pcr. cepr and cepi were amplified from b. cepacia genomovars i and iii, b. stabilis, and b. vietnamiensis. cepr was also amplified from b. multivorans and b. cepacia genomovar vi. bviir were amplified from b. vietnamiensis. all genomovars produced n-octanoyl-l-homoserine lactone and n-hexanoyl-l-homoserine lactone. b. vietnamiensis and b. cepacia genomovar vii produced ... | 2001 | 11402012 |
| brucella abortus cyclic beta-1,2-glucan mutants have reduced virulence in mice and are defective in intracellular replication in hela cells. | null cyclic beta-1,2-glucan synthetase mutants (cgs mutants) were obtained from brucella abortus virulent strain 2308 and from b. abortus attenuated vaccinal strain s19. both mutants show greater sensitivity to surfactants like deoxycholic acid, sodium dodecyl sulfate, and zwittergent than the parental strains, suggesting cell surface alterations. although not to the same extent, both mutants display reduced virulence in mice and defective intracellular multiplication in hela cells. the b. abort ... | 2001 | 11401996 |
| establishing a direct role for the bartonella bacilliformis invasion-associated locus b (ialb) protein in human erythrocyte parasitism. | the invasion-associated locus a and b genes (ialab) of bartonella bacilliformis were previously shown to confer an erythrocyte-invasive phenotype upon escherichia coli, indirectly implicating their role in virulence. we report the first direct demonstration of a role for ialb as a virulence factor in b. bacilliformis. the presence of a secretory signal sequence and amino acid sequence similarity to two known outer membrane proteins involved in virulence suggested that ialb was an outer membrane ... | 2001 | 11401976 |
| effect of cell membrane of agrobacterium radiobacter on enhancing d-amino acids production from racemic hydantoins. | an interesting phenomenon was observed that the existence of the intact cell membrane can enhance the d-amino acids production from d,l-5-substituted hydantoins by reacting with the whole cells of agrobacterium radiobacter. two intracellular enzymes were involved in the reaction process. the first enzyme d-hydantoinase converted hydantoins to carbamoyl derivatives which were further converted to d-amino acids by d-amidohydrolase. the amount of d-amino acids produced from hydantoins by the intact ... | 2001 | 11397462 |
| efficient vir gene induction in agrobacterium tumefaciens requires vira, virg, and vir box from the same ti plasmid. | the vir genes of octopine, nopaline, and l,l-succinamopine ti plasmids exhibit structural and functional similarities. however, we observed differences in the interactions between octopine and nopaline vir components. the induction of an octopine vire(a6)::lacz fusion (psm358cd) was 2.3-fold higher in an octopine strain (a348) than in a nopaline strain (c58). supplementation of the octopine virg(a6) in a nopaline strain with psm358 did not completely restore vire(a6) induction. however, addition ... | 2001 | 11395473 |
| global versus local regulatory roles for lrp-related proteins: haemophilus influenzae as a case study. | lrp (leucine-responsive regulatory protein) plays a global regulatory role in escherichia coli, affecting expression of dozens of operons. numerous lrp-related genes have been identified in different bacteria and archaea, including asnc, an e. coli gene that was the first reported member of this family. pairwise comparisons of amino acid sequences of the corresponding proteins shows an average sequence identity of only 29% for the vast majority of comparisons. by contrast, lrp-related proteins f ... | 2001 | 11395465 |
| the agrobacterium tumefaciens rnd homolog is required for trar-mediated quorum-dependent activation of ti plasmid tra gene expression. | conjugal transfer of agrobacterium tumefaciens ti plasmids is regulated by quorum sensing via trar and its cognate autoinducer, n-(3-oxo-octanoyl)-l-homoserine lactone. we isolated four tn5-induced mutants of a. tumefaciens c58 deficient in trar-mediated activation of tra genes on ptic58deltaaccr. these mutations also affected the growth of the bacterium but had no detectable influence on the expression of two tester gene systems that are not regulated by quorum sensing. in all four mutants tn5 ... | 2001 | 11395455 |
| activities of vire1 and the vire1 secretion chaperone in export of the multifunctional vire2 effector via an agrobacterium type iv secretion pathway. | agrobacterium tumefaciens uses a type iv secretion system to deliver oncogenic nucleoprotein particles and effector proteins, such as the multifunctional vire2 protein, to plant cells. in this study, we examined the function of vire1 and its product, the vire1 secretion chaperone, in mediating vire2 export. a nonpolar vire1 null mutant accumulated low levels of vire2, and trans expression of vire1 in this mutant only partially restored vire2 abundance. deletion of vire1 did not affect transcript ... | 2001 | 11395448 |
| transcription factor rf2a alters expression of the rice tungro bacilliform virus promoter in transgenic tobacco plants. | the promoter from rice tungro bacilliform badnavirus (rtbv) is expressed only in phloem tissues in transgenic rice plants. rf2a, a b-zip protein from rice, is known to bind to the box ii cis element near the tata box of the promoter. here, we report that the full-length rtbv promoter and a truncated fragment e of the promoter, comprising nucleotides -164 to +45, result in phloem-specific expression of beta-glucuronidase (gus) reporter genes in transgenic tobacco plants. when a fusion gene compri ... | 2001 | 11390974 |
| kinetics and mechanism of dna uptake into the cell nucleus. | gene transfer to eukaryotic cells requires the uptake of exogenous dna into the cell nucleus. except during mitosis, molecular access to the nuclear interior is limited to passage through the nuclear pores. here we demonstrate the nuclear uptake of extended linear dna molecules by a combination of fluorescence microscopy and single-molecule manipulation techniques, using the latter to follow uptake kinetics of individual molecules in real time. the assays were carried out on nuclei reconstituted ... | 2001 | 11390964 |
| intracellular accumulation of mannopine, an opine produced by crown gall tumors, transiently inhibits growth of agrobacterium tumefaciens. | pydh208, a cosmid clone from the octopine-mannityl opine-type tumor-inducing (ti) plasmid pti15955 confers utilization of mannopine (mop) and agropine (agr) on agrobacterium tumefaciens strain nt1. nt1 harboring pydh208 with an insertion mutation in mocc, which codes for mop oxidoreductase, not only fails to utilize mop as a sole carbon source, but also was inhibited in its growth by mop and agr. in contrast, the growth of mutants with insertions in other tested moc genes was not inhibited by ei ... | 2001 | 11386375 |
| agrobacterium rhizogenes-transformed roots of medicago truncatula for the study of nitrogen-fixing and endomycorrhizal symbiotic associations. | medicago truncatula, a diploid autogamous legume, is currently being developed as a model plant for the study of root endosymbiotic associations, including nodulation and mycorrhizal colonization. an important requirement for such a plant is the possibility of rapidly introducing and analyzing chimeric gene constructs in root tissues. for this reason, we developed and optimized a convenient protocol for agrobacterium rhizogenes-mediated transformation of m. truncatula. this unusual protocol, whi ... | 2001 | 11386364 |
| toxicity and mutagenesis of chrysotile asbestos to agrobacterium radiobacter. | the mutation of agrobacterium radiobacter cells exposed to chrysotile asbestos was examined by the random amplified polymorphic dna (rapd) method. approximately 1.4 kbp of dna in a. radiobacter, which was not amplified strongly in the cells that were not exposed to asbestos, was amplified in the cells that were exposed to asbestos. mutation in genomic dna of a. radiobacter was found to be induced by asbestos. specific dna that was amplified by asbestos present in pcr products and that which exis ... | 2001 | 11381330 |
| abrogation of disease development in plants expressing animal antiapoptotic genes. | an emerging topic in plant biology is whether plants display analogous elements of mammalian programmed cell death during development and defense against pathogen attack. in many plant-pathogen interactions, plant cell death occurs in both susceptible and resistant host responses. for example, specific recognition responses in plants trigger formation of the hypersensitive response and activation of host defense mechanisms, resulting in restriction of pathogen growth and disease development. sev ... | 2001 | 11381106 |
| tetracycline antibiotics: mode of action, applications, molecular biology, and epidemiology of bacterial resistance. | tetracyclines were discovered in the 1940s and exhibited activity against a wide range of microorganisms including gram-positive and gram-negative bacteria, chlamydiae, mycoplasmas, rickettsiae, and protozoan parasites. they are inexpensive antibiotics, which have been used extensively in the prophlylaxis and therapy of human and animal infections and also at subtherapeutic levels in animal feed as growth promoters. the first tetracycline-resistant bacterium, shigella dysenteriae, was isolated i ... | 2001 | 11381101 |
| replicating potato spindle tuber viroid rna is accompanied by short rna fragments that are characteristic of post-transcriptional gene silencing. | the low molecular weight fraction of tomato plants inoculated with potato spindle tuber viroid (pstvd) contains a population of short pstvd-specific rnas of either polarity. the main constituents were rnas of 22 and 23 nt representing different domains of the viroid genome. the occurrence of such distinct rna species indicated that the nuclear replicating pstvd rna induces post-transcriptional gene silencing. the short rnas were slightly more abundant at 30 days post-inoculation than at later st ... | 2001 | 11376158 |
| ecological fitness, genomic islands and bacterial pathogenicity. a darwinian view of the evolution of microbes. | the compositions of bacterial genomes can be changed rapidly and dramatically through a variety of processes including horizontal gene transfer. this form of change is key to bacterial evolution, as it leads to 'evolution in quantum leaps'. horizontal gene transfer entails the incorporation of genetic elements transferred from another organism-perhaps in an earlier generation-directly into the genome, where they form 'genomic islands', i.e. blocks of dna with signatures of mobile genetic element ... | 2001 | 11375927 |
| exploitation of plasmid pmrc01 to direct transfer of mobilizable plasmids into commercial lactococcal starter strains. | genetic analysis of the 60.2-kb lactococcal plasmid pmrc01 revealed a 19.6-kb region which includes putative genes for conjugal transfer of the plasmid and a sequence resembling an origin of transfer (orit). this orit-like sequence was amplified and cloned on a 312-bp segment into pci372, allowing the resultant plasmid, prh001, to be mobilized at a frequency of 3.4 x 10(-4) transconjugants/donor cell from an mg1363 (reca mutant) host containing pmrc01. all of the resultant chloramphenicol-resist ... | 2001 | 11375207 |
| quantitative pcr method for diagnosis of citrus bacterial canker. | for diagnosis of citrus bacterial canker by pcr, an internal standard is employed to ensure the quality of the dna extraction and that proper requisites exist for the amplification reaction. the ratio of pcr products from the internal standard and bacterial target is used to estimate the initial bacterial concentration in citrus tissues with lesions. | 2001 | 11375206 |
| requirement for phosphoglucomutase in exopolysaccharide biosynthesis in glucose- and lactose-utilizing streptococcus thermophilus. | to study the influence of phosphoglucomutase (pgm) activity on exopolysaccharide (eps) synthesis in glucose- and lactose-growing streptococcus thermophilus, a knockout pgm mutant and a strain with elevated pgm activity were constructed. the pgma gene, encoding pgm in s. thermophilus ly03, was identified and cloned. the gene was functional in escherichia coli and was shown to be expressed from its own promoter. the pgma-deficient mutant was unable to grow on glucose, while the mutation did not af ... | 2001 | 11375188 |
| complete denitration of nitroglycerin by bacteria isolated from a washwater soakaway. | four axenic bacterial species capable of biodegrading nitroglycerin (glycerol trinitrate [gtn]) were isolated from soil samples taken from a washwater soakaway at a disused gtn manufacturing plant. the isolates were identified by 16s rrna gene sequence homology as pseudomonas putida, an arthrobacter species, a klebsiella species, and a rhodococcus species. each of the isolates utilized gtn as its sole nitrogen source and removed nitro groups sequentially from gtn to produce glycerol dinitrates a ... | 2001 | 11375172 |
| natural transformation of pseudomonas fluorescens and agrobacterium tumefaciens in soil. | little information is available concerning the occurrence of natural transformation of bacteria in soil, the frequency of such events, and the actual role of this process on bacterial evolution. this is because few bacteria are known to possess the genes required to develop competence and because the tested bacteria are unable to reach this physiological state in situ. in this study we found that two soil bacteria, agrobacterium tumefaciens and pseudomonas fluorescens, can undergo transformation ... | 2001 | 11375171 |
| hydrolysis of 4-hydroxybenzoic acid esters (parabens) and their aerobic transformation into phenol by the resistant enterobacter cloacae strain em. | enterobacter cloacae strain em was isolated from a commercial dietary mineral supplement stabilized by a mixture of methylparaben and propylparaben. it harbored a high-molecular-weight plasmid and was resistant to high concentrations of parabens. strain em was able to grow in liquid media containing similar amounts of parabens as found in the mineral supplement (1,700 and 180 mg of methyl and propylparaben, respectively, per liter or 11.2 and 1.0 mm) and in very high concentrations of methylpara ... | 2001 | 11375144 |
| regulation of rpos gene expression in pseudomonas: involvement of a tetr family regulator. | the rpos gene encodes the sigma factor which was identified in several gram-negative bacteria as a central regulator during stationary phase. rpos gene regulation is known to respond to cell density, showing higher expression in stationary phase. for pseudomonas aeruginosa, it has been demonstrated that the cell-density-dependent regulation response known as quorum sensing interacts with this regulatory response. using the rpos promoter of p. putida, we identified a genomic tn5 insertion mutant ... | 2001 | 11371535 |
| reconstitution of acetosyringone-mediated agrobacterium tumefaciens virulence gene expression in the heterologous host escherichia coli. | the ability to utilize escherichia coli as a heterologous system in which to study the regulation of agrobacterium tumefaciens virulence genes and the mechanism of transfer dna (t-dna) transfer would provide an important tool to our understanding and manipulation of these processes. we have previously reported that the rpoa gene encoding the alpha subunit of rna polymerase is required for the expression of lacz gene under the control of virb promoter (virbp::lacz) in e. coli containing a constit ... | 2001 | 11371534 |
| virb7 lipoprotein is exocellular and associates with the agrobacterium tumefaciens t pilus. | agrobacterium tumefaciens transfers oncogenic t-dna and effector proteins to plant cells via a type iv secretion pathway. this transfer system, assembled from the products of the virb operon, is thought to consist of a transenvelope mating channel and the t pilus. when screened for the presence of virb and vire proteins, material sheared from the cell surface of octopine strain a348 was seen to possess detectable levels of virb2 pilin, virb5, and the virb7 outer membrane lipoprotein. material sh ... | 2001 | 11371529 |
| functional analysis of the agrobacterium tumefaciens t-dna transport pore protein virb8. | the virb8 protein of agrobacterium tumefaciens is essential for dna transfer to plants. virb8, a 237-residue polypeptide, is an integral membrane protein with a short n-terminal cytoplasmic domain. it interacts with two transport pore proteins, virb9 and virb10, in addition to itself. to study the role of these interactions in dna transfer and to identify essential amino acids of virb8, we introduced random mutations in virb8 by the mutagenic pcr method. the putative mutants were tested for virb ... | 2001 | 11371528 |
| ralstonia solanacearum needs motility for invasive virulence on tomato. | ralstonia solanacearum, a widely distributed and economically important plant pathogen, invades the roots of diverse plant hosts from the soil and aggressively colonizes the xylem vessels, causing a lethal wilting known as bacterial wilt disease. by examining bacteria from the xylem vessels of infected plants, we found that r. solanacearum is essentially nonmotile in planta, although it can be highly motile in culture. to determine the role of pathogen motility in this disease, we cloned, charac ... | 2001 | 11371523 |
| tnt1 transposition events are induced by in vitro transformation of arabidopsis thaliana, and transposed copies integrate into genes. | tissue culture has been shown to induce the transposition of plant transposable elements; their insertion at novel sites results in somaclonal variation. introduction of the tobacco retrotransposon tnt1 into arabidopsis thaliana by co-cultivation of root explants with agrobacterium tumefaciens induces its transposition at a high frequency, but no transposed copies are found in plants transformed by the in planta procedure. transposition occurs in the transformed root cells or in the calli derive ... | 2001 | 11370870 |
| generation of pcr-based dna fragments for specific detection of streptomyces saraceticus n45. | streptomyces saraceticus strain n45, a saprophytic gram-positive bacteria, has been shown to harbor high chitinase activity. due to its potential use in biological control, the cloning of chitinase genes and the development of methods to quickly and precisely detect its presence have become necessary. in this study, pcr-based random amplified polymorphic dna (rapd) and pcr strategies were used to amplify random dna fragments from the genome of s. saraceticus n45. three amplified dna fragments, 4 ... | 2001 | 11370759 |
| transient gfp expression in nicotiana plumbaginifolia suspension cells: the role of gene silencing, cell death and t-dna loss. | the transient nature of t-dna expression was studied with a gfp reporter gene transferred to nicotiana plumbaginifolia suspension cells from agrobacterium tumefaciens. individual gfp-expressing protoplasts were isolated after 4 days' co-cultivation. the protoplasts were cultured without selection and 4 weeks later the surviving proto-calluses were again screened for gfp expression. of the proto-calluses initially expressing gfp, 50% had lost detectable gfp activity during the first 4 weeks of cu ... | 2001 | 11352457 |
| phytochrome-mediated photoperiod perception, shoot growth, glutamine, calcium, and protein phosphorylation influence the activity of the poplar bark storage protein gene promoter (bspa). | in poplars (populus), bspa encodes a 32-kd bark storage protein that accumulates in the inner bark of plants exposed to either short-day (sd) photoperiods or elevated levels of nitrogen. in this study, poplars transformed with a chimeric gene consisting of the bspa promoter fused to beta-glucuronidase (uida) were used to investigate the transcriptional regulation of the bspa promoter. photoperiodic activation of the bspa promoter was shown to involve perception by phytochrome and likely involves ... | 2001 | 11351097 |
| temperature-sensitive alleles of rsw2 link the korrigan endo-1,4-beta-glucanase to cellulose synthesis and cytokinesis in arabidopsis. | an 8.5-kb cosmid containing the korrigan gene complements the cellulose-deficient rsw2-1 mutant of arabidopsis. three temperature-sensitive alleles of rsw2 show single amino acid mutations in the putative endo-1,4-beta-glucanase encoded by kor. the f1 from crosses between kor-1 and rsw2 alleles shows a weak, temperature-sensitive root phenotype. the shoots of rsw2-1 seedlings produce less cellulose and accumulate a short chain, readily extractable glucan resembling that reported for rsw1 (which ... | 2001 | 11351091 |
| sugar-binding activity of pea lectin enhances heterologous infection of transgenic alfalfa plants by rhizobium leguminosarum biovar viciae. | transgenic alfalfa (medicago sativa l. cv regen) roots carrying genes encoding soybean lectin or pea (pisum sativum) seed lectin (psl) were inoculated with bradyrhizobium japonicum or rhizobium leguminosarum bv viciae, respectively, and their responses were compared with those of comparably inoculated control plants. we found that nodule-like structures formed on alfalfa roots only when the rhizobial strains produced nod factor from the alfalfa-nodulating strain, sinorhizobium meliloti. uninfect ... | 2001 | 11351077 |
| regulation of flowering in arabidopsis by an flc homologue. | the arabidopsis flc gene encodes a mads domain protein that acts as a repressor of flowering. late-flowering vernalization-responsive ecotypes and mutants have high steady-state levels of flc transcript, which decrease during the promotion of flowering by vernalization. therefore, flc has a central role in regulating the response to vernalization. we have isolated an arabidopsis gene, maf1, which encodes a protein that is closely related to flc. overexpression studies demonstrate that maf1 produ ... | 2001 | 11351076 |
| constitutive overexpression of cytosolic glutamine synthetase (gs1) gene in transgenic alfalfa demonstrates that gs1 may be regulated at the level of rna stability and protein turnover. | glutamine synthetase (gs) catalyzes the atp-dependent condensation of nh4+ with glutanate to yield glutamine. gene constructs consisting of the cauliflower mosaic virus (camv) 35s promoter driving a cytosolic isoform of gs (gs1) gene have been introduced into alfalfa (medicago sativa). although transcripts for the transgene were shown to accumulate to high levels in the leaves, they were undetectable in the nodules. however, significant amounts of beta-glucuronidase activity could be detected in ... | 2001 | 11351075 |
| intracellular survival of brucella spp. in human monocytes involves conventional uptake but special phagosomes. | brucella spp. are facultative intracellular parasites of various mammals, including humans, typically infecting lymphoid as well as reproductive organs. we have investigated how b. suis and b. melitensis enter human monocytes and in which compartment they survive. peripheral blood monocytes readily internalized nonopsonized brucellae and killed most of them within 12 to 18 h. the presence of brucella-specific antibodies (but not complement) increased the uptake of bacteria without increasing the ... | 2001 | 11349069 |
| type ii secretion and pathogenesis. | 2001 | 11349009 | |
| chvd, a chromosomally encoded atp-binding cassette transporter-homologous protein involved in regulation of virulence gene expression in agrobacterium tumefaciens. | a yeast two-hybrid screen searching for chromosomally encoded proteins that interact with the agrobacterium tumefaciens virb8 protein was carried out. this screen identified an interaction candidate homologous to the partial sequence of a gene that had previously been identified in a transposon screen as a potential regulator of virg expression, chvd. in this report, the cloning of the entire chvd gene is described and the gene is sequenced and characterized. insertion of a promoterless lacz gen ... | 2001 | 11344138 |
| isolation of a new broad-host-range incq-like plasmid, ptc-f14, from the acidophilic bacterium acidithiobacillus caldus and analysis of the plasmid replicon. | a moderately thermophilic (45 to 50 degrees c), highly acidophilic (ph 1.5 to 2.5), chemolithotrophic acidithiobacillus caldus strain, f, was isolated from a biooxidation process used to treat nickel ore. trans-alternating field electrophoresis analysis of total dna from the a. caldus cells revealed two plasmids of approximately 14 and 45 kb. the 14-kb plasmid, designated ptc-f14, was cloned and shown by replacement of the cloning vector with a kanamycin resistance gene to be capable of autonomo ... | 2001 | 11344137 |
| staphylococcus aureus resistance to human defensins and evasion of neutrophil killing via the novel virulence factor mprf is based on modification of membrane lipids with l-lysine. | defensins, antimicrobial peptides of the innate immune system, protect human mucosal epithelia and skin against microbial infections and are produced in large amounts by neutrophils. the bacterial pathogen staphylococcus aureus is insensitive to defensins by virtue of an unknown resistance mechanism. we describe a novel staphylococcal gene, mprf, which determines resistance to several host defense peptides such as defensins and protegrins. an mprf mutant strain was killed considerably faster by ... | 2001 | 11342591 |
| hyperosmotic stress induces the rapid phosphorylation of a soybean phosphatidylinositol transfer protein homolog through activation of the protein kinases spk1 and spk2. | although phosphatidylinositol transfer proteins (pitps) are known to serve critical functions in regulating a varied array of signal transduction processes in animals and yeast, the discovery of a similar class of proteins in plants occurred only recently. here, we report the participation of ssh1p, a soybean pitp-like protein, in the early events of osmosensory signal transduction in plants, a function not attributed previously to animal or yeast pitps. exposure of plant tissues to hyperosmotic ... | 2001 | 11340192 |
| arabidopsis plc1 is required for secondary responses to abscisic acid signals. | the role of inositol 1,4,5-trisphosphate (ins[1,4,5]p3) in transducing the abscisic acid (aba) signal during seed germination and in the stress responses of mature plants is poorly understood. we have considered the contributions of the phospholipase c1 (encoded by atplc1) and an ins(1,4,5)p3 5-phosphatase (encoded by atip5pii) to aba signaling by using a modified version of the glucocorticoid-inducible system to regulate transgene expression. in the presence of the dexamethasone (dex) inducer, ... | 2001 | 11340187 |
| influence of kdel on the fate of trimeric or assembly-defective phaseolin: selective use of an alternative route to vacuoles. | the tetrapeptide kdel is commonly found at the c terminus of soluble proteins of the endoplasmic reticulum (er), and it contributes to their localization by interacting with a receptor that recycles between the golgi complex and the er. we investigated the effects of the addition of kdel to phaseolin, a protein normally delivered from the er to storage vacuoles via the golgi complex. we show that kdel prevents acquisition of trans-golgi-specific glycan modifications and causes interactions with ... | 2001 | 11340185 |
| identification of arabidopsis histone deacetylase hda6 mutants that affect transgene expression. | a mutant screen was conducted in arabidopsis that was based on deregulated expression of auxin-responsive transgenes. two different tightly regulated (i.e., very low expression in the absence of auxin treatment and very high expression after exogenous auxin treatment) auxin-responsive promoters were used to drive the expression of both a beta-glucuronidase (gus) reporter gene and a hygromycin phosphotransferase (hph)-selectable marker gene. this screen yielded several mutants, and five of the mu ... | 2001 | 11340181 |
| overexpression of the tobacco tsi1 gene encoding an erebp/ap2-type transcription factor enhances resistance against pathogen attack and osmotic stress in tobacco. | using mrna differential display analysis, we isolated a salt-induced transcript that showed a significant sequence homology with an erebp/ap2 dna binding motif from oilseed rape plants. with this cdna fragment as a probe, cdna clone tsi1 (for tobacco stress-induced gene1) was isolated from a tobacco cdna library. rna gel blot analysis indicated that transcripts homologous with tsi1 were induced not only in nacl-treated leaves but also in leaves treated with ethephon or salicylic acid. transient ... | 2001 | 11340180 |
| the arabidopsis mutant cev1 has constitutively active jasmonate and ethylene signal pathways and enhanced resistance to pathogens. | jasmonates (jas) inhibit plant growth and induce plant defense responses. to define genes in the arabidopsis ja signal pathway, we screened for mutants with constitutive expression of a luciferase reporter for the ja-responsive promoter from the vegetative storage protein gene vsp1. one mutant, named constitutive expression of vsp1 (cev1), produced plants that were smaller than wild type, had stunted roots with long root hairs, accumulated anthocyanin, had constitutive expression of the defense- ... | 2001 | 11340179 |