Frankia forms a nitrogen-fixing symbiosis with actinorhizal plants. We report a draft genome sequence for Frankia sp. strain BCU110501, a nitrogen-fixing actinobacterium isolated from nodules of Discaria trinevis grown in the Patagonia... more
Frankia forms a nitrogen-fixing symbiosis with actinorhizal plants. We report a draft genome sequence for Frankia sp. strain BCU110501, a nitrogen-fixing actinobacterium isolated from nodules of Discaria trinevis grown in the Patagonia region of Argentina.
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Research Interests: Genetics, Caenorhabditis elegans, Symbiosis, Biology, Medicine, and 15 moreMutualism, Biological Sciences, Animals, Genome, Enterobacteriaceae, Biological evolution, Serratia marcescens, Serratia, Host Pathogen Interactions, Species Specificity, EPN, Photorhabdus, Molecular Sequence Data, Urea pathway, and Medical and Health Sciences
Research Interests: Biochemistry, Chemistry, Kinetics, Membrane Proteins, Medicine, and 15 moreATPase, Escherichia coli, Microbial genetic and drug resistance, Membrane, Genotype, Cooperativity, Multienzyme complexes, Antimony, Arsenite, Protein Binding, Arsenic Poisoning, Biochemistry and cell biology, microbial drug resistance, Enzyme Induction, and Cell Membrane
Found widespread around the globe, Serratia are Gram-negative bacteria capable of thriving in a diverse number of environments that include water, soil, and the digestive tracts of various animals. Known for their ability to produce a... more
Found widespread around the globe, Serratia are Gram-negative bacteria capable of thriving in a diverse number of environments that include water, soil, and the digestive tracts of various animals. Known for their ability to produce a myriad of extracellular enzymes, these bacteria also produce various secondary metabolites that directly contribute to their survival. While the effects Serratia species have on other organisms range from parasitic to symbiotic, what these bacteria have in common is their ability to resist attack, respond appropriately to environmental conditions, and outcompete other microorganisms when colonizing their respective niche. This review highlights the mechanisms utilized by Serratia species that drive their ubiquitous nature, with emphasis on the latest findings. Also discussed is how secreted compounds drive these bacteria towards pathogenic, mutualistic, and antagonistic associations.
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ABSTRACT The actinorhizal bacteria Frankia produce vesicles, specialized cell structures that are the site of nitrogen fixation. Vesicles were isolated and purified from Frankia strain EAN1pec grown in culture. The physiological... more
ABSTRACT The actinorhizal bacteria Frankia produce vesicles, specialized cell structures that are the site of nitrogen fixation. Vesicles were isolated and purified from Frankia strain EAN1pec grown in culture. The physiological properties of these purified vesicles were characterized with respect to their metabolic capacity and compared to that of the intact mycelium. Our results indicate that the vesicle is unable to generate ATP. When compared on a protein basis, the total adenylate nucleotide pool of intact mycelium was 10-fold higher than total pool obtained with purified vesicles. Purified vesicles exhibit low rates of endogenous respiration, about 5-fold lower than the rates obtained with intact mycelia. The addition of succinate increased vesicle respiration by 1.6-fold, but several other carbon sources had no effect on respiration. Vesicle respiration showed a degree of insensitivity to cyanide. The addition of succinate, a respirable substrate, did not increase the energy charge or ATP level of purified vesicles. In the case of intact mycelium. controls, the absence or presence of an energy source directly affected the energy charge and ATP levels. These results combined with those of previous studies indicate that the vesicles is dependent on the ATP supplied from the hyphae to which they are attached.
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... Titre du document / Document title. Identification of the truncated hemoglobin gene in Frankia. Auteur(s) / Author(s). NIEMANN James M. (1) ; TJEPKEMA John D. (2) ; TISA Louis S. (1) ; Affiliation(s) du ou des auteurs / Author(s)... more
... Titre du document / Document title. Identification of the truncated hemoglobin gene in Frankia. Auteur(s) / Author(s). NIEMANN James M. (1) ; TJEPKEMA John D. (2) ; TISA Louis S. (1) ; Affiliation(s) du ou des auteurs / Author(s) Affiliation(s). ...
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Actinorhizal root nodules result from the interaction between a nitrogen-fixing actinomycete from the genus Frankia and roots of dicotyledonous trees and shrubs belonging to 25 genera within 8 plant families. Most actinorhizal plants can... more
Actinorhizal root nodules result from the interaction between a nitrogen-fixing actinomycete from the genus Frankia and roots of dicotyledonous trees and shrubs belonging to 25 genera within 8 plant families. Most actinorhizal plants can reach high rates of nitrogen fixation comparable to those found in root nodule symbiosis of the legumes. As a consequence, these trees are able to grow in poor and disturbed soils and are important elements in plant communities worldwide. While the basic knowledge of these symbiotic associations is still poorly understood, actinorhizal symbioses emerged recently as original systems to explore developmental strategies to form nitrogen-fixing nodules. Many tools have been developed in recent years to explore the interaction between Frankia and actinorhizal plants including molecular biology, biochemistry, and genomics. However, technical difficulties are often encountered to explore these symbiotic interactions, mainly linked to the woody nature of the plant species and to the lack of genetic tools for their bacterial symbionts. In this chapter, we report an inventory of the main recent molecular tools and techniques developed for studying actinorhizae.
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ABSTRACT Caulerpa is a tropical marine coenocytic green alga that coexists with bacteria. The exact relationship between these bacteria and the plant has not been established. The bacteria may be associated with the plant surface or exist... more
ABSTRACT Caulerpa is a tropical marine coenocytic green alga that coexists with bacteria. The exact relationship between these bacteria and the plant has not been established. The bacteria may be associated with the plant surface or exist as endosymbionts. Electron micrographs revealed the presence of at least three different bacterial morphologies within the plant cell. Four Caulerpa species were examined for the existence of bacteria by the use of a culture-independent approach. A protocol was developed to extract plant cytoplasm that was free of contaminating surface materials. DNA was extracted from the cytoplasmic fraction, washed plant pieces, and resultant wash solution. Denaturing gradient gel electrophoresis (DGGE) of PCR-amplified 16S rDNA was used as a molecular fingerprinting technique to profile the bacterial community. Individual DGGE bands representing unique bacteria were excised from the gel and sequenced to identify these organisms. Samples from four plant species were examined to determine if all Caulerpa species coexisted with same or different bacterial species. Preliminary results indicate that Caulerpa cytoplasm contains endosymbionts and the bacterial strains within individual Caulerpa species differed.
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A study was made of the ability of four strains of Frankia, representing two distinct host-compatibility groups, to utilize various carbon sources for growth. Isolates EAN1pec and EuI1c, representatives of host-compatibility group II,... more
A study was made of the ability of four strains of Frankia, representing two distinct host-compatibility groups, to utilize various carbon sources for growth. Isolates EAN1pec and EuI1c, representatives of host-compatibility group II, utilized a variety of sugars and sugar alcohols as carbon sources. Isolates CpI1 and ACN1AG, members of host-compatibility group I, did not use these substrates for growth. All of the isolates studied except for EAN1pec utilized propionate for growth. The only one of the four isolates unable to grow on dicarboxylic acids was EuI1c. Vesicles were detected microscopically during growth of EAN1pec and ACN1AG in media containing ammonia. The numbers and size of vesicles, however, were greater in media without ammonia. Strain ACN1AG did not form vesicles in any of the media when incubated at temperatures greater than 33 °C. The CpI1 isolate formed vesicles only when grown in ammoniafree media. Vesicles were not formed by strain EuI1c in any of the media. Sporulation of the four isolates was carbon-source dependent. Isolate CpI1 formed sporangia when grown in propionate-containing medium at 20 °C but formed none in the medium at 33 °C.
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Research Interests: Biology, Membrane Proteins, Biological Chemistry, Medicine, Biological Sciences, and 15 moreATPase, Escherichia coli, Bacteria, Alkaline phosphatase, Membrane, CHEMICAL SCIENCES, Molecular cloning, Multienzyme complexes, Protein Conformation, Amino Acid Sequence, Base Sequence, Membrane Protein, Membrane topology, Molecular Sequence Data, and Medical and Health Sciences
Three resting stages (spores, microcysts, and macrocysts) of the Dictyosteliaceae were found to possess low levels of trehalase activity. A significant increase in the activity of trehalase was detected upon germination. The increase in... more
Three resting stages (spores, microcysts, and macrocysts) of the Dictyosteliaceae were found to possess low levels of trehalase activity. A significant increase in the activity of trehalase was detected upon germination. The increase in activity appeared to be dependent on protein synthesis.
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Spores may be reversibly activated by the application of heat, dimethyl sulfoxide, urea, or ethylene glucol. Severe changes in four environmental variables (high osmotic pressure, low oxygen tension, low or high pH, and low or high... more
Spores may be reversibly activated by the application of heat, dimethyl sulfoxide, urea, or ethylene glucol. Severe changes in four environmental variables (high osmotic pressure, low oxygen tension, low or high pH, and low or high temperature) interfere with the germination process. Spores at the end of the postactivation lag phase of germination were usually deactivated if exposed to severe environmental conditions and thus did not swell; spores in the swelling and emergence stages of germination were killed if exposed to severe environmental conditions. The oxygen uptake which began during spore activation was primarily attributable to a cyanide-sensitive pathway and secondarily to a salicylhydroxamic acid (SHAM) sensitive pathway. Inhibition of the SHAM-sensitive pathway did not cause spore deactivation while the addition of cyanide resulted in rapid spore deactivation. Treatment of activated spores with azide or environmental shifts also resulted in inhibition of oxygen uptake and spore deactivation. Deactivating spores did not demonstrate the amino acid incorporation, uridine incorporation, and expression of trehalase activity which is found in the later stages of germinating control spores. Protein synthesis inhibitors did not cause spore deactivation or a decrease in oxygen uptake but they inhibited amino acid incorporation and the expression of trehalase activity in swollen spores. It is concluded that control of respiratory activity is involved in regulation of reversible activation.
Research Interests: Biochemistry, Microbiology, Medical Microbiology, Biology, Medicine, and 15 moreFungal Spores, Temperature, Osmotic pressure, Fluorides, Dictyostelium, Germination, Veterinary Sciences, Cyanides, Spore, Hydroxamic Acids, Oxygen Consumption, Cycloheximide, trehalase, Dictyostelium discoideum, and Azides
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R-factor mediated bacterial resistance to arsenical salts occurs by active extrusion of the toxic oxyanions from cells of gram negative bacteria. The ars operon of the conjugative plasmid R773 encodes an anion pump. The pump has two... more
R-factor mediated bacterial resistance to arsenical salts occurs by active extrusion of the toxic oxyanions from cells of gram negative bacteria. The ars operon of the conjugative plasmid R773 encodes an anion pump. The pump has two polypeptide components. The catalytic subunit, the ArsA protein, is an oxyanion-stimulated ATPase. The membrane component, the ArsB protein, has been localized in the inner membrane of Escherichia coli. The ArsA and ArsB proteins have been postulated to form a membrane complex which functions as an anion-translocating ATPase. In this study evidence is presented showing that expression of the arsB gene is required to anchor the ArsA protein to the inner membrane. Binding studies with purified ArsA to membranes with and without the arsB gene product confirm this requirement. Membranes of uncA mutants containing both the ArsA and ArsB proteins exhibit arsenite(antimonite)-stimulated ATPase activity. These results support the model in which the ArsA protein is the catalytic energy transducing component of the anion pump, whereas the integral membrane ArsB protein serves as both the anion channel and membrane binding site for the ArsA protein.
Research Interests: Chemistry, Arsenic, Biology, Membrane Proteins, Biological Chemistry, and 15 moreMedicine, Gene expression, Ion Channels, Biological Sciences, Escherichia coli, Microbial genetic and drug resistance, Plasmids, CHEMICAL SCIENCES, Anions, Multienzyme complexes, Antimony, Immunoblotting, Cell Membrane, Medical and Health Sciences, and Arsenites
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ABSTRACT
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Research Interests: Microbiology, Carbon Dioxide, Medical Microbiology, Biology, Medicine, and 15 moreStructural Analysis, Quantitative analysis, Genetic Diversity, Nitrogen Fixation, Bacteria, Nitrogen, Hemoglobin, Frankia, Oxygen, Genetic variation, Quantitative Analysis, Molecular weight, Culture Media, Hemoglobins, and Carboxyhemoglobin
Research Interests: Microbiology, Bacteriology, Biology, Regulation, Medicine, and 15 moreGene expression, Biological Sciences, Mycobacterium tuberculosis, Gram Positive, Nitric oxide, Bacteria, Polymerase Chain Reaction, Nitrogen, Plant sciences, Hemoglobin, Frankia, Oxygen Transport, Oxygen, Amino Acid Sequence, and Medical and Health Sciences
Research Interests: Chemistry, Hydrogen, Kinetics, Melanin, Algae, and 15 moreMedicine, Biological Sciences, Electron Transfer, Bacteria, Iron Oxide, Hydrous Ferric Oxide, Iron, Electron Transport, Fourier transform infrared spectroscopy, Melanine, Cell Surface Markers, Ferric Compounds, Shewanella, Cell Surface Hydrophobicity, and Medical and Health Sciences
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The family Frankiaceae, within the order Actinomycetales, contains bacteria isolated mainly from root nodules and occasionally from soil. Members of the genus Frankia have been found associated with the roots of 23 genera of dicots... more
The family Frankiaceae, within the order Actinomycetales, contains bacteria isolated mainly from root nodules and occasionally from soil. Members of the genus Frankia have been found associated with the roots of 23 genera of dicots belonging to eight families. Historically, strains isolated in pure culture were grouped into two physiological categories, those that use carbohydrates and those that do not. Newer genomic information indicated that frankiae in general differ markedly in their complements of genes. Besides physiological grouping, these isolates were placed into four plant-compatibility groups (1-infective on Alnus and Myrica, 2-infective on Casuarina and Myrica, 3-infective on Elaeagnaceae and Myrica, 4-infective only on Elaeagnaceae). A 16S rRNA gene-based phylogenetic study, comprising non-isolated endophytes, yielded four clusters or clades, three of which are symbiotic (1-infective on Alnus and Casuarinaceae except Gymnostoma, 2-non-isolated strains in nodules of Rosaceae-Datisca-Coriaria-Rhamnaceae, 3-infective on Elaeagnaceae and Gymnostoma) and a fourth cluster that groups non-infective and non-effective strains. These groupings have been confirmed on the whole by analysis of other loci. DNA-DNA hybridization studies have yielded 12–15 genospecies, only one of which has been named, Frankia alni; one Candidatus Frankia datiscae was recently named to accommodate the genome of an endophyte in nodules of Datisca glomerata. The family Frankiaceae is close to Acidothermus, Cryptosporangium, Geodermatophilaceae (Geodermatophilus, Modestobacter, Blastococcus), Nakamurella, Sporichthya, and Fodinicola and was grouped into suborder Frankineae. A recent rearrangement has resulted in the elevation of suborder Frankineae to order Frankiales (Normand and Benson 2012b) containing families Acidothermaceae, Cryptosporangiaceae, Frankiaceae, Geodermatophilaceae, Nakamurellaceae, and Sporichthyaceae as well as the incertae sedis Fodinicola feengrottensis