scholarly journals The Structure of Ineffective Root Nodules of Legumes: An Unusual New Type of Ineffectiveness, and an Appraisal of Present Knowledge

1957 ◽  
Vol 10 (3) ◽  
pp. 233 ◽  
Author(s):  
FJ Bergersen
Keyword(s):  
Root Nodules ◽  
Subterranean Clover ◽  
Present Knowledge ◽  
Host Tissue ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Infection Threads ◽  
New Type ◽  
Slow Growing ◽  
Nodule Tissue

A new type of symbiotic ineffectiveness in subterranean clover is described in which very slow-growing nodules are produced. In these the nodule bacteria are not released from the infection threads, where they multiply at the expense of the host tissue. Comparison of nuclear size of normal effective nodules with that of these ineffective nodules suggests that the nodule tissue is almost devoid of the disomatic cells in which the nitrogen-fixing bacteroid form of Rhizobium normally develops. The bacterial strains giving rise to these nodules were obtained as stable variants of a strain producing structurally and cytologically normal nodules.

Formation and structure of root nodules induced on Macroptilium atropurpureum inoculated with various species of Rhizobium

1991 ◽  
Vol 69 (7) ◽  
pp. 1520-1532 ◽  
Author(s):  
Michael J. Trinick ◽  
Celia Miller ◽  
Paul A. Hadobas
Keyword(s):  
Rhizobium Leguminosarum ◽  
Rhizobium Meliloti ◽  
Root Nodules ◽  
Matrix Material ◽  
Immunogold Labelling ◽  
Infection Threads ◽  
Glass Tubes ◽  
Infected Cells ◽  
Macroptilium Atropurpureum ◽  
Nodule Tissue

Fifteen strains of Rhizobium leguminosarum biovar trifolii formed ineffective nodules and (or) nodule-like structures (rhizobia were re-isolated from both structures) on Macroptilium atropurpureum grown in enclosed glass tubes. Bacteria were observed among the parenchyma cells surrounding the nodule-like structures. One variant of R. leguminosarum biovar trifolii (NGR66/ST) isolated from M. atropurpureum formed nodules on this host that exhibited abnormal intercellular and intracellular infection. The bacteria (NGR66/ST) were contained within threadlike structures, surrounded by matrix material. The identities of the Rhizobium strains were confirmed serologically after reisolation and in sections of nodule tissue using immunogold labelling. Rhizobium leguminosarum biovar phaseoli strain NGR76 isolated from Phaseolus vulgaris formed nodules on M. atropurpureum resembling those formed by effective Bradyrhizobium strains. The association was partially effective in nitrogen fixation, and this was reflected in the nodule structure. The percentage of cells infected was lower than that in fully effective nodules. There was a high frequency of infected cells showing degeneration; these were located throughout the nodule tissue and were often adjacent to healthy infected cells. The rhizobia appeared to infect new nodule cells via infection threads, which were abundant both intercellularly and intracellularly in young, mature, and degenerating host nodule cells. Strains of R. leguminosarum biovar viceae and Rhizobium meliloti were unable to induce nodule-like structures on M. atropurpureum. Key words: Macroptilium, Bradyrhizobium, Rhizobium, microscopy, nodule, structure.

scholarly journals Rhizobia and other legume nodule bacteria richness in brazilian Araucaria angustifolia forest

2007 ◽  
Vol 64 (4) ◽  
pp. 400-408 ◽  
Author(s):  
Daniel Renato Lammel ◽  
Pedro Henrique Santin Brancalion ◽  
Carlos Tadeu Santos Dias ◽  
Elke Jurandy Bran Nogueira Cardoso
Keyword(s):  
Root Nodules ◽  
Phenotypic Characterization ◽  
Growth Media ◽  
Legume Species ◽  
Araucaria Angustifolia ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Rhizobium Tropici ◽  
Ph Change ◽  
Growth Standards

The Araucaria Forest is a sub-type of the Atlantic Forest, dominated by Araucaria angustifolia, which is considered an endangered species. The understory has a high diversity of plant species, including several legumes. Many leguminous plants nodulate with rhizobia and fix atmospheric nitrogen, contributing to forest sustainability. This work aimed at bacteria isolation and phenotypic characterization from the root nodules of legumes occurring in Araucaria Forests, at Campos do Jordão State Park, Brazil. Nodule bacteria were isolated in YMA growth media and the obtained colonies were classified according to their growth characteristics (growth rate, color, extra cellular polysaccharide production and pH change of the medium). Data were analyzed by cluster and principal components analysis (PCA). From a total of eleven collected legume species, nine presented nodules, and this is the first report on nodulation of five of these legume species. Two hundred and twelve bacterial strains were isolated from the nodules, whose nodule shapes varied widely and there was a great phenotypic richness among isolates. This richness was found among legume species, individuals of the same species, different nodule shapes and even among isolates of the same nodule. These isolates could be classified into several groups, two up to six according to each legume, most of them different from the used growth standards Rhizobium tropici, Bradyrhizobium elkanii and Burkholderia sp. There is some evidence that these distinct groups may be related to the presence of Burkholderia spp. in the nodules of these legumes.

scholarly journals Localization of Superoxide Dismutases and Hydrogen Peroxide in Legume Root Nodules

2004 ◽  
Vol 17 (12) ◽  
pp. 1294-1305 ◽  
Author(s):  
Maria C. Rubio ◽  
Euan K. James ◽  
Maria R. Clemente ◽  
Bruna Bucciarelli ◽  
Maria Fedorova ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Enzyme Inhibitors ◽  
Root Nodules ◽  
Strong Support ◽  
Immunogold Electron Microscopy ◽  
Superoxide Dismutases ◽  
Signal Molecule ◽  
Infection Threads ◽  
Infected Cells ◽  
Nodule Tissue

Superoxide dismutases (SODs) catalyze the dismutation of superoxide radicals to O2 and H2O2 and thus represent a primary line of antioxidant defense in all aerobic organisms. H2O2 is a signal molecule involved in the plant's response to pathogen attack and other stress conditions as well as in nodulation. In this work, we have tested the hypothesis that SODs are a source of H2O2 in indeterminate alfalfa (Medicago sativa) and pea (Pisum sativum) nodules. The transcripts and proteins of the major SODs of nodules were localized by in situ RNA hybridization and immunogold electron microscopy, respectively, whereas H2O2 was localized cytochemically by electron microscopy of cerium-perfused nodule tissue. The transcript and protein of cytosolic CuZnSOD are most abundant in the meristem (I) and invasion (II) zones, interzone II-III, and distal part of the N2-fixing zone (III), and those of MnSOD in zone III, especially in the infected cells. At the subcellular level, CuZnSOD was found in the infection threads, cytosol adjacent to cell walls, and apoplast, whereas MnSOD was in the bacteroids, bacteria within infection threads, and mitochondria. The distinct expression pattern of CuZnSOD and MnSOD suggests specific roles of the enzymes in nodules. Large amounts of H2O2 were found at the same three nodule sites as CuZnSOD but not in association with MnSOD. This colocalization led us to postulate that cytosolic CuZnSOD is a source of H2O2 in nodules. Furthermore, the absence or large reduction of H2O2 in nodule tissue preincubated with enzyme inhibitors (cyanide, azide, diphenyleneiodonium, diethyldithiocarbamate) provides strong support to the hypothesis that at least some of the H2O2 originates by the sequential operation of an NADPH oxidase- like enzyme and CuZnSOD. Results also show that there is abundant H2O2 associated with degrading bacteroids in the senescent zone (IV), which reflects the oxidative stress ensued during nodule senescence.

Genetics of symbiosis and nitrogen fixation in legumes

1969 ◽  
Vol 172 (1029) ◽  
pp. 417-437 ◽  
Keyword(s):  
Nitrogen Fixation ◽  
Bacterial Strain ◽  
Host Plants ◽  
Strain Differences ◽  
Homogeneous Material ◽  
Developmental Sequence ◽  
Bacterial Strains ◽  
Nodule Bacteria ◽  
Microbial Genetics ◽  
Nodular Tissue

Soon after the isolation of nodule bacteria in 1888, differences were recognized in the ability of bacterial strains to form nodules on particular host plants and in the nitrogen-fixing ability of the nodules so formed. These and other symbiotic heterogeneities were attributed, sometimes correctly, to bacterial strain differences, not then thought to be open to formal genetic analysis. The realization that the host plant was an essential component of this variability came only gradually, stimulated by observations of host varietal differences and by the demand for reliable and homogeneous material for experimental work. Only within the last two decades has host variability been studied by plant breeding, and bacterial strain differences by some of the methods of microbial genetics. This review, except for a brief reference to earlier work of some historic interest, will consider only genetic problems open to investigation by these methods. The developmental sequence in all legume nodules is broadly similar. The initial infection phases are followed by the induction of the nodule, the invasion of part of the nodular tissue and culminate in bacteroid formation and nitrogen fixation; the genetics of symbiosis will be considered in this context.

scholarly journals Evaluation of Lipases from Wild Microbial Strains as Biocatalysts in Biodiesel Production

Separations ◽  
2018 ◽  
Vol 5 (4) ◽  
pp. 53 ◽  
Author(s):  
Carlos Luna ◽  
Diego Luna ◽  
Felipa Bautista ◽  
Juan Calero ◽  
Antonio Romero ◽  
...  
Keyword(s):  
Biodiesel Production ◽  
Purification Process ◽  
Bacterial Strains ◽  
Production Methods ◽  
Mild Conditions ◽  
New Type ◽  
Microbial Strains ◽  
The Stability ◽  
Microbial Strain ◽  
Biodiesel Industry

In this study, the evaluation of the catalytic behavior of several wild bacterial strains in the 1,3-selective ethanolysis of triglycerides with ethanol to produce a new type of biodiesel (Ecodiesel) that integrates glycerol as monoacylglycerols was carried out. The Ecodiesel production not only avoids the elimination of glycerol, which is largely generated as a by-product in the biodiesel industry, but also results in an increase in the biofuel yield. The wild microbial strain samples were obtained from several lipophilic organisms. In addition to evaluate the enzymatic extracts, the minimum grade of purification of the strains, necessary to obtain similar results to those attained with commercial lipases was studied. This purification treatment included a dialysis followed by a lyophilization process. Such extracts were directly used as biocatalysts in the transesterification reaction of sunflower oil with ethanol, attaining much better results (yield close to 100%) than those obtained with strains which were not submitted to the purification process (yields lower than 10%). Furthermore, the results here obtained are similar to those obtained with commercial lipases but were achieved under mild conditions and lower reaction time (2 h). In addition, the stability of the enzymatic extracts was corroborated by subsequent reactions, showing no loss of activity. Thus, this study brings to light that enzymatic extracts obtained by a very simple purification process can be economically competitive with the conventional biodiesel production methods.

scholarly journals EVALUATION OF PHOSPHATE SOLUBILIZING ABILITY OF THE BACTERIAL STRAINS ISOLATED FROM ROOT NODULES OF PIGEON PEA (CAJANUS CAJAN)

2021 ◽  
Vol 21 (Suppliment-1) ◽  
pp. 1562-1566
Author(s):  
Santosh Kumar ◽  
Ramesh Kumar Singh ◽  
Shiv Charan Kumar ◽  
Umakant Banjare ◽  
Arun Kumar Patel ◽  
...  
Keyword(s):  
Cajanus Cajan ◽  
Root Nodules ◽  
Pigeon Pea ◽  
Bacterial Strains ◽  
Phosphate Solubilizing

scholarly journals Heteroaryl-Ethylenes as New Lead Compounds in the Fight against High Priority Bacterial Strains

2021 ◽  
Author(s):  
Dafne Bongiorno ◽  
Nicolò Musso ◽  
Paolo Giuseppe Bonacci ◽  
Dalida A. Bivona ◽  
Mariacristina Massimino ◽  
...  
Keyword(s):  
Bacterial Infections ◽  
Rectal Adenocarcinoma ◽  
Molecular Structures ◽  
Bacteriostatic Activity ◽  
Bacterial Strains ◽  
Biological Assays ◽  
Antibiotic Compounds ◽  
Stilbene Derivatives ◽  
New Type ◽  
Activity Spectrum

The widespread use of antibiotics has led to a gradual increase in drug-resistant bacterial infections, which severely weakens the clinical efficacy of antibacterial therapies. In recent decades, stilbenes aroused great interest because of their high bioavailability, as well as for their manifold biological activity. Our research efforts are focused on synthetic heteroaromatic stilbene deriva-tives as they represent a potentially new type of antibiotic with a wide antibacterial spectrum. Herein, a preliminary molecular modeling study and a versatile synthetic scheme allowed us to define eight heteroaromatic stilbene derivatives with potential antimicrobial activity. In order to evaluate our compound’s activity spectrum and antibacterial ability, Minimum Inhibitory Con-centration (MIC) and Minimum Bactericidal Concentration (MBC) tests have been performed on Gram-positive and Gram-negative ATCC strains. Compounds PB4, PB5, PB7 and PB8 showed the best values in terms of MIC and were also evaluated for MBC, which however was found to be greater than MIC, confirming a bacteriostatic activity. For all compounds, we evaluated toxici-ty on colon-rectal adenocarcinoma cells tumor cells (CaCo2), once established that the whole se-lected set was more active than 5-Fluorouracil in reducing CaCo-2 cells viability. To the best of our knowledge, the biological assays have shown for these derivatives an excellent bacteriostatic activity, compared to similar molecular structures previously reported, thus paving the way for a new class of antibiotic compounds.

scholarly journals Burkholderia phymatum Strains Capable of Nodulating Phaseolus vulgaris Are Present in Moroccan Soils

2010 ◽  
Vol 76 (13) ◽  
pp. 4587-4591 ◽  
Author(s):  
C. Talbi ◽  
M. J. Delgado ◽  
L. Girard ◽  
A. Ramírez-Trujillo ◽  
J. Caballero-Mellado ◽  
...  
Keyword(s):  
Phylogenetic Analysis ◽  
Phaseolus Vulgaris ◽  
16S Rrna ◽  
Root Nodules ◽  
Bacterial Strains

ABSTRACT Phylogenetic analysis of 16S rRNA, nodC, and nifH genes of four bacterial strains isolated from root nodules of Phaseolus vulgaris grown in Morocco soils were identified as Burkholderia phymatum. All four strains formed N2-fixing nodules on P. vulgaris and Mimosa, Acacia, and Prosopis species and reduced acetylene to ethylene when cultured ex planta.

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