scholarly journals Homology of genes for exopolysaccharide synthesis in Rhizobium leguminosarum and effect of cloned exo genes on nodule formation.

1993 ◽  
Vol 40 (4) ◽  
pp. 477-482
Author(s):  
A Skorupska ◽  
M Deryło
Keyword(s):  
Rhizobium Leguminosarum ◽  
The Other ◽  
Nodule Formation ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Bamhi Fragment ◽  
Other Hand ◽  
Indeterminate Nodules ◽  
Total Dna ◽  
Rhizobium Sp

A 5.4 kb BamHI fragment of R. leguminosarum bv. trifolii TA1 was found to carry genes involved in exopolysaccharide synthesis (exo genes). This fragment was strongly hybridized to the total DNA from R. l. bv. viciae and bv. phaseoli digested with EcoRI. No homology was found with total DNA of R. meliloti and Rhizobium sp. NGR 234. The exo genes from R. l. bv. trifolii TA1 conjugally introduced into R. l. bv. viciae 1302 considerably affected the symbiosis: the nodules induced on vetch were abortive and did not fix nitrogen. On the other hand, Phaseolus beans infected with R. l. bv. phaseoli harbouring R. l. bv. trifolii exo genes formed the nitrogen-fixing nodules. It can be concluded that additional copies of exo genes introduced into wild type Rhizobium leguminosarum strains can disturb the synthesis of acidic exopolysaccharides and affect symbiosis of the plants forming indeterminate nodules, but do not affect symbiosis of the plants forming the determinate nodules.

Genetic characterization of Rhizobium sp. strain TAL1145 that nodulates tree legumes

1994 ◽  
Vol 40 (3) ◽  
pp. 208-215 ◽  
Author(s):  
M. L. C. George ◽  
J. P. W. Young ◽  
D. Borthakur
Keyword(s):  
Rhizobium Leguminosarum ◽  
Genetic Characterization ◽  
Rhizobium Meliloti ◽  
Wild Type ◽  
Tree Legumes ◽  
Wide Range ◽  
The Common ◽  
Rrna Sequences ◽  
Rhizobium Sp

Rhizobium sp. strain TALI 145 nodulates Leucaena ieucocephaia and Phaseolus vulgaris, in addition to a wide range of tropical tree legumes. Six overlapping clones that complemented nodulation defects in leucaena and bean rhizobia were isolated and a 40-kb map of the symbiosis region was constructed. The common nod and nifA genes were situated approximately 17 kb apart, with the nodlJ genes in between. These clones enabled a derivative of TAL1145 carrying a partially deleted pSym to form ineffective nodules on both leucaena and bean, and a similar derivative of Rhizobium etli TAL182 to form ineffective nodules on bean. When two representative clones, pUHR9 and pUHR114, were each transferred to wild-type rhizobial strains, they allowed ineffective nodulation by Rhizobium meliloti on both leucaena and bean and by Rhizobium leguminosarum bv. viciae on bean. Transconjugants of R. leguminosarum bv. trifolii formed effective nodules on leucaena and ineffective nodules on bean. Tn5 mutagenesis of the symbiosis region resulted in a variety of nodulation and fixation phenotypes on leucaena and bean. On the basis of 16S rRNA sequences, TAL1145 was found to be distinct from both R. tropici and NGR234, the two groups of leucaena symbionts that were previously described.Key words: Rhizobium, Leucaena leucocephala, nodulation, nitrogen fixation.

Nutritional Requirement for 4-Aminobenzoate Caused by Mutation of Dihydropteroate Synthetase

1976 ◽  
Vol 31 (5-6) ◽  
pp. 285-287 ◽  
Author(s):  
Helmut Rappold ◽  
Adelbert Bacher
Keyword(s):  
Parent Strain ◽  
The Other ◽  
Synthetase Activity ◽  
Nutritional Requirement ◽  
Wild Type ◽  
Aerobacter Aerogenes ◽  
Low Level ◽  
Other Hand ◽  
High Concentrations

Abstract Aerobacter aerogenes mutant 62-1 AC requires high concentrations of 4-aminobenzoate for growth. The mutant accumulates N-glucosyl-4-aminobenzoate and has an intact 4-aminobenzoate synthetase (Bacher, Gilch, Rappold, and Lingens, Z. Naturforsch. 28c, 614 - 617 [1973]). On the other hand the ability of the mutant to synthesize dihydropteroate is markedly reduced. The dihydropteroate synthetase level of mutant 62-1 AC is 1% as compared to the parent strain. Spontaneous revertants of mutant 62-1 AC show wild type levels of dihydropteroate synthetase. We conclude that the requirement for 4-aminobenzoate in mutant 62-1 AC is due to poor utilization of 4-aminobenzoate as a consequence of the low level of dihydropteroate synthetase activity.

H-Ras Is Involved in the Inside-out Signaling Pathway of Interleukin-3–Induced Integrin Activation

Blood ◽  
1999 ◽  
Vol 93 (5) ◽  
pp. 1540-1548 ◽  
Author(s):  
Hirohiko Shibayama ◽  
Naoyuki Anzai ◽  
Stephen E. Braun ◽  
Seiji Fukuda ◽  
Charlie Mantel ◽  
...  
Keyword(s):  
Signaling Pathway ◽  
Dominant Negative ◽  
The Other ◽  
Wild Type ◽  
Integrin Activation ◽  
Mapk Kinase ◽  
Interleukin 3 ◽  
Other Hand ◽  
Inside Out ◽  
Constitutively Active

Abstract The proto-oncogene product, p21ras, has been implicated in the cellular mechanism of adhesion, although its precise role has been controversial. Numerous cytokines and growth-factors activate Ras, which is an important component of their growth-promoting signaling pathways. On the other hand, the role of Ras in cytokine-induced adhesion has not been elucidated. We therefore investigated the function of H-Ras in the inside-out signaling pathway of interleukin-3 (IL-3)–induced integrin activation in the murine Baf3 cell line after transfection of cells with either constitutively active, dominant-negative, or wild-type H-Ras cDNAs. Adhesion of Baf3 cells to fibronectin was induced by IL-3 in a dose-dependent manner via very late antigen-4 (VLA-4; 4β1 integrins) and VLA-5 (5β1 integrins) activation. On the other hand, IL-4 did not induce the adhesion of Baf3 cells to fibronectin, although IL-4 did stimulate the cell proliferation of Baf3 cells. Constitutively active H-Ras–transfected Baf3 cells adhered to fibronectin without IL-3 stimulation through VLA-4 and VLA-5, whereas dominant-negative H-Ras–transfected Baf3 cells showed significantly less adhesion induced by IL-3 compared with wild-type and constitutively active H-Ras–transfected Baf3 cells. Anti-β1 integrin antibody (clone; 9EG7), which is known to change integrin conformation and activate integrins, induced the adhesion of dominant-negative H-Ras–transfected Baf3 cells as much as the other types of H-Ras–transfected Baf3 cells. 8-Br-cAMP, Dibutyryl-cAMP, Ras-Raf-1 pathway inhibitors, and PD98059, a MAPK kinase inhibitor, suppressed proliferation and phosphorylation of MAPK detected by Western blotting with anti–phospho-MAPK antibody, but not adhesion of any type of H-Ras–transfected Baf3 cells, whereas U-73122, a phospholipase C (PLC) inhibitor, suppressed adhesion of these cells completely. These data indicate that H-Ras and PLC, but not Raf-1, MAPK kinase, or the MAPK pathway, are involved in the inside-out signaling pathway of IL-3–induced VLA-4 and VLA-5 activation in Baf3 cells.

The influence of the number of nodule bacteria applied to the seed upon nodule formation in legumes

1929 ◽  
Vol 19 (2) ◽  
pp. 373-381 ◽  
Author(s):  
H. G. Thornton
Keyword(s):  
Pure Culture ◽  
Field Trial ◽  
Root Hairs ◽  
The Other ◽  
Pot Experiment ◽  
Nodule Formation ◽  
Nodule Bacteria ◽  
Soil Population ◽  
Other Hand ◽  
The Difference

In a field trial with lucerne grown from seed treated with varying doses of culture it was found that the numbers of nodules were increased as the dose was raised from 2,500 to 20,000 organisms per seed (56 to 7 Ib. of seed per culture). Storing the seed for periods up to 28 days between inoculation and sowing, caused some loss in the nodule numbers. This loss was greatest between 1 and 7 days' storage.The difference in dose of culture and in period of storage did not significantly affect the crop subsequently obtained from the inoculated plots, whose yield was, however, much above the uninoculated.In a pot experiment made with runner beans, it was found that increase in the dose of culture above 1,280,000,000 organisms per pot containing six seeds was still capable of increasing nodule numbers but not to an extent proportional to the increase in dose.The experiment does not exclude the possibility that the restriction in effect of very heavy doses may be due to the soil population becoming saturated with the bacteria. On the other hand, observations on lucerne plants grown aseptically on agar and inoculated with a pure culture, showed that even when excessive numbers of the bacteria immediately surrounded the root hairs, only 4 per cent, of these were infected.

scholarly journals Glucomannan-Mediated Attachment of Rhizobium leguminosarum to Pea Root Hairs Is Required for Competitive Nodule Infection

2008 ◽  
Vol 190 (13) ◽  
pp. 4706-4715 ◽  
Author(s):  
Alan Williams ◽  
Adam Wilkinson ◽  
Martin Krehenbrink ◽  
Daniela M. Russo ◽  
Angeles Zorreguieta ◽  
...  
Keyword(s):  
Biofilm Formation ◽  
Rhizobium Leguminosarum ◽  
Root Hairs ◽  
The Other ◽  
Plant Interactions ◽  
Wild Type ◽  
Polysaccharide Synthesis ◽  
Surface Polysaccharides

ABSTRACT The Rhizobium leguminosarum biovar viciae genome contains several genes predicted to determine surface polysaccharides. Mutants predicted to affect the initial steps of polysaccharide synthesis were identified and characterized. In addition to the known cellulose (cel) and acidic exopolysaccharide (EPS) (pss) genes, we mutated three other loci; one of these loci (gmsA) determines glucomannan synthesis and one (gelA) determines a gel-forming polysaccharide, but the role of the other locus (an exoY-like gene) was not identified. Mutants were tested for attachment and biofilm formation in vitro and on root hairs; the mutant lacking the EPS was defective for both of these characteristics, but mutation of gelA or the exoY-like gene had no effect on either type of attachment. The cellulose (celA) mutant attached and formed normal biofilms in vitro, but it did not form a biofilm on root hairs, although attachment did occur. The cellulose-dependent biofilm on root hairs appears not to be critical for nodulation, because the celA mutant competed with the wild-type for nodule infection. The glucomannan (gmsA) mutant attached and formed normal biofilms in vitro, but it was defective for attachment and biofilm formation on root hairs. Although this mutant formed nodules on peas, it was very strongly outcompeted by the wild type in mixed inoculations, showing that glucomannan is critical for competitive nodulation. The polysaccharide synthesis genes around gmsA are highly conserved among other rhizobia and agrobacteria but are absent from closely related bacteria (such as Brucella spp.) that are not normally plant associated, suggesting that these genes may play a wide role in bacterium-plant interactions.

scholarly journals Symbiotic Plasmid Rearrangement in Rhizobium leguminosarum bv. viciae VF39SM

2001 ◽  
Vol 183 (6) ◽  
pp. 2141-2144 ◽  
Author(s):  
Xue-Xian Zhang ◽  
Bob Kosier ◽  
Ursula B. Priefer
Keyword(s):  
Parent Strain ◽  
Rhizobium Leguminosarum ◽  
Plasmid Profile ◽  
The Other ◽  
Dna Fragments ◽  
Symbiotic Genes ◽  
Symbiotic Plasmid ◽  
Other Hand

ABSTRACT A rearrangement between the symbiotic plasmid (pRleVF39d) and a nonsymbiotic plasmid (pRleVF39b) in Rhizobium leguminosarumbv. viciae VF39 was observed. The rearranged derivative showed the same plasmid profile as its parent strain, but hybridization to nod, fix, and nif genes indicated that most of the symbiotic genes were now present on a plasmid corresponding in size to pRleVF39b instead of pRleVF39d. On the other hand, some DNA fragments originating from pRleVF39b now hybridized to the plasmid band at the position of pRleVF39d. These results suggest that a reciprocal but unequal DNA exchange between the two plasmids had occurred.

Abstract 16603: Appropriate Timing of Pacemaker Implantation in Patients With Wild-Type and Variant Amyloidogenic Transthyretin Cardiac Amyloidosis

Circulation ◽  
2020 ◽  
Vol 142 (Suppl_3) ◽  
Author(s):  
Yusei Kawahara ◽  
Miwa Ito ◽  
Tadashi Hoshiyama ◽  
Hisanori Kanazawa ◽  
Kenichi Tsujita
Keyword(s):  
Cardiac Amyloidosis ◽  
Pacemaker Implantation ◽  
The Other ◽  
Cardiac Conduction ◽  
Wild Type ◽  
Conduction Disorders ◽  
Other Hand ◽  
Conduction Disorder ◽  
Second Degree

Background and Objectives: It has been shown that cardiac conduction disorders can be seen in patients with wild-type amyloidogenic transthyretin (ATTRwt) and variant ATTR (ATTRv) cardiac amyloidosis. However, its appropriate timing of pacemaker implantation has not been clarified yet. Methods and Results: The consecutive 100 patients with ATTRwt cardiac amyloidosis who diagnosed by myocardium biopsy and/or technetium-99m-pyrophosphate scintigraphy and 62 patients with ATTRv cardiac amyloidosis who diagnosed by means of genetic screening were included in this study. In patients with ATTRwt cardiac amyloidosis, 21 patients have normal conduction at the time of diagnosis. However, conduction disorder had seen in only 5 patient (first degree atrioventricular block (AVB); 4 patients, complete AVB; 1 patients) and only one patient underwent cardiac implantable electric device (CIED) implantation during follow-up period. On the other hand, in patients with ATTRv cardiac amyloidosis, 36 patients have normal conduction at the time of diagnosis. However, conduction disorder had seen in 13 patient (first degree AVB; 8 patients, second degree AVB; 3 patients, trifascicular block; 1 patients, complete AVB; 1 patients) (5/21 vs 13/36, p=0.335) and 6 patients underwent CIED implantation during follow-up period (1/21 vs 6/36, p=0.186). Furthermore, in ATTRwt cardiac amyloidosis, 10 patients (first degree AVB; 2 patients, second degree AVB; 1 patient, trifascicular block; 7 patients) had underwent CIED implantation because of cardiac conduction disorders and/or prevention of sudden cardiac death. However, only 4 patients with trifascicular block progressed to complete AVB.On the other hand, In ATTRv cardiac amyloidosis, 14 patients (first degree AVB; 2 patients, second degree AVB; 4 patient, trifascicular block; 8 patients) had underwent CIED implantation for same reason. However, only 3 patients with trifascicular block progressed to complete AVB. Conclusions: Patients with ATTRv cardiac amyloidosis were more likely to progress conduction disorders than those with ATTRwt cardiac amyloidosis. However, prophylactic pacemaker implantation might had not need in both ATTRwt and ATTRv patients with first or second degree AVB.

scholarly journals Suppression of Viral Replication by Stress-Inducible GADD34 Protein via the Mammalian Serine/Threonine Protein Kinase mTOR Pathway

2007 ◽  
Vol 81 (20) ◽  
pp. 11106-11115 ◽  
Author(s):  
Kahori Minami ◽  
Yukihiro Tambe ◽  
Ryosuke Watanabe ◽  
Takahiro Isono ◽  
Masataka Haneda ◽  
...  
Keyword(s):  
Viral Replication ◽  
Critical Role ◽  
Cellular Protein ◽  
Mtor Pathway ◽  
The Other ◽  
Mtor Signaling Pathway ◽  
Wild Type ◽  
Other Hand ◽  
Vesicular Stomatitis ◽  
Pathway Inhibition

ABSTRACT GADD34 is a protein that is induced by a variety of stressors, including DNA damage, heat shock, nutrient deprivation, energy depletion, and endoplasmic reticulum stress. Here, we demonstrated that GADD34 induced by vesicular stomatitis virus (VSV) infection suppressed viral replication in wild-type (WT) mouse embryo fibroblasts (MEFs), whereas replication was enhanced in GADD34-deficient (GADD34-KO) MEFs. Enhanced viral replication in GADD34-KO MEFs was reduced by retroviral gene rescue of GADD34. The level of VSV protein expression in GADD34-KO MEFs was significantly higher than that in WT MEFs. Neither phosphorylation of eIF2α nor cellular protein synthesis was correlated with viral replication in GADD34-KO MEFs. On the other hand, phosphorylation of S6 and 4EBP1, proteins downstream of mTOR, was suppressed by VSV infection in WT MEFs but not in GADD34-KO MEFs. GADD34 was able to associate with TSC1/2 and dephosphorylate TSC2 at Thr1462. VSV replication was higher in TSC2-null cells than in TSC2-expressing cells, and constitutively active Akt enhanced VSV replication. On the other hand, rapamycin, an mTOR inhibitor, significantly suppressed VSV replication in GADD34-KO MEFs. These findings demonstrate that GADD34 induced by VSV infection suppresses viral replication via mTOR pathway inhibition, indicating that cross talk between stress-inducible GADD34 and the mTOR signaling pathway plays a critical role in antiviral defense.

Mutagenesis-induced conformational change in domain B of a pullulan-hydrolyzing α-amylase TVA I

Amylase ◽  
2018 ◽  
Vol 2 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Takashi Tonozuka ◽  
Takanori Nihira ◽  
Masahiro Mizuno ◽  
Atsushi Nishikawa ◽  
Shigehiro Kamitori
Keyword(s):  
Kinetic Analysis ◽  
Crystal Structures ◽  
Conformational Change ◽  
The Other ◽  
Wild Type ◽  
Other Hand ◽  
Thermoactinomyces Vulgaris ◽  
Catalytic Cleft

Abstract An α-amylase from Thermoactinomyces vulgaris, TVA I, hydrolyzes both α-1,4- and α-1,6-glucosidic linkages. Two variants of TVA I have been previously constructed, one containing a substitution of three residues, Ala357- Gln359-Tyr360, with Val-Asn-Glu (AQY/VNE), and the other bearing a deletion of 11 residues from Ala363 to Asn373 (Del11). The activities of both AQY/VNE and Del11 for the α-1,4-glucosidic linkage of maltotriose were decreased compared to that of wild-type TVA I, while the activities of the two variants for the α-1,6-glucosidic linkage of a trisaccharide, isopanose, were less significantly altered. Here, we determined the crystal structures of AQY/VNE and Del11. The structure of AQY/VNE was almost isomorphous with that of wild-type TVA I. On the other hand, the structure of Del11 showed that a conformational change in domain B was induced by the 11-residue deletion, causing narrowing of the catalytic cleft. Taken together with the results of kinetic analysis, this narrower catalytic cleft is likely responsible for the preference of the TVA I enzyme for the α-1,6-glucosidic linkage.

scholarly journals Sinorhizobium meliloti Mutants Deficient in Phosphatidylserine Decarboxylase Accumulate Phosphatidylserine and Are Strongly Affected during Symbiosis with Alfalfa

2008 ◽  
Vol 190 (20) ◽  
pp. 6846-6856 ◽  
Author(s):  
Miguel Angel Vences-Guzmán ◽  
Otto Geiger ◽  
Christian Sohlenkamp
Keyword(s):  
Sinorhizobium Meliloti ◽  
Minimal Medium ◽  
Root Nodule ◽  
Membrane Lipids ◽  
Nodule Formation ◽  
Deficient Mutant ◽  
Nitrogen Fixing ◽  
Wild Type ◽  
Root Nodule Symbiosis ◽  
Nodule Symbiosis

ABSTRACT Sinorhizobium meliloti contains phosphatidylglycerol, cardiolipin, phosphatidylcholine, and phosphatidylethanolamine (PE) as major membrane lipids. PE is formed in two steps. In the first step, phosphatidylserine synthase (Pss) condenses serine with CDP-diglyceride to form phosphatidylserine (PS), and in the second step, PS is decarboxylated by phosphatidylserine decarboxylase (Psd) to form PE. In this study we identified the sinorhizobial psd gene coding for Psd. A sinorhizobial mutant deficient in psd is unable to form PE but accumulates the anionic phospholipid PS. Properties of PE-deficient mutants lacking either Pss or Psd were compared with those of the S. meliloti wild type. Whereas both PE-deficient mutants grew in a wild-type-like manner on many complex media, they were unable to grow on minimal medium containing high phosphate concentrations. Surprisingly, the psd-deficient mutant could grow on minimal medium containing low concentrations of inorganic phosphate, while the pss-deficient mutant could not. Addition of choline to the minimal medium rescued growth of the pss-deficient mutant, CS111, to some extent but inhibited growth of the psd-deficient mutant, MAV01. When the two distinct PE-deficient mutants were analyzed for their ability to form a nitrogen-fixing root nodule symbiosis with their alfalfa host plant, they behaved strikingly differently. The Pss-deficient mutant, CS111, initiated nodule formation at about the same time point as the wild type but did form about 30% fewer nodules than the wild type. In contrast, the PS-accumulating mutant, MAV01, initiated nodule formation much later than the wild type and formed 90% fewer nodules than the wild type. The few nodules formed by MAV01 seemed to be almost devoid of bacteria and were unable to fix nitrogen. Leaves of alfalfa plants inoculated with the mutant MAV01 were yellowish, indicating that the plants were starved for nitrogen. Therefore, changes in lipid composition, including the accumulation of bacterial PS, prevent the establishment of a nitrogen-fixing root nodule symbiosis.

Sign in / Sign up

Export Citation Format

Share Document