Long Term Effects of Chernobyl Contamination on DNA Repair Function and Plant Resistance to Different Biotic and Abiotic Stress Factors

Thirty years after the Chernobyl explosion we still lack information regarding the genetic effects of radionuclide contamination on the plant population. For example, are plants adapting to the low dose of chronic ionising irradiation and showing improved resistance to radiation damage? Are they coping with changing/increased pathogenicity of fungi and viruses in the Chernobyl exclusion (ChE) zone? Are plant populations rapidly accumulating mutational load and should we expect rapid micro-evolutionary changes in plants in the Chernobyl area? This review will try to summarise the current knowledge on these aspects of plant genetics and ecology and draw conclusions on the importance of further studies in the area around Chernobyl

Optimization of Bacillus intermedius glutamyl endopeptidase production by recombinant strain of Bacillus subtilis and localization of glutamyl endopeptidase in Bacillus subtilis cells

The biosynthesis of glutamyl endopeptidase from Bacillus intermedius 3-19 in recombinant strain of Bacillus subtilis has been investigated. The composition of culture medium, which yielded the maximum glutamyl endopeptidase production by B. subtilis strain, was developed, employing response surface methodology. The pathways of regulation of glutamyl endopeptidase synthesis in recombinant strain in general were found to be similar to those of other serine proteinases and of glutamyl endopeptidase in B. intermedius. Biosynthesis of glutamyl endopeptidase by recombinant strain was suppressed by easily metabolizable carbon sources. Ions of Ca2+(2mM), Mg2+ (1mM), and Co2+ (5mM) stimulated production of the proteinase by B. subtilis. In case of Co2+ ions strong stimulating effect (up to 400%) possibly was due to the release of the membrane-bound enzyme into the culture liquid, according to the mechanism described earlier for B. intermedius. The addition of Fe2+, Zn2+, and Cu2+ to the medium at concentrations of 1 to 10mM led to the gradual decrease in proteinase production by B. subtilis. This study has demonstrated a requirement by recombinant strain for excess carbon, nitrogen, and inorganic phosphate for active glutamyl endopeptidase production. In contrast with B. intermedius, for the maximum yield of endopeptidase by B. subtilis the presence in the culture medium of yeast extract at concentration of 2% and one of the organic substrates of proteinase - casein or gelatin (1%) was found to be necessary. Our study has revealed the changes in the pathways of secretion of glutamyl endopeptidase of B. intermedius by B. subtilis cells, expressing the gene for glutamyl endopeptidase from the plasmids: the part of the enzyme (2-5%) remained bound to the cell wall. © 2002 Elsevier Science Inc. All rights reserved

Optimized medium for the efficient production of Bacillus intermedium glutamyl endopeptidase by the recombinant Bacillus subtilis strain AJ73

A nutrient medium was elaborated for the efficient production of glutamyl endopeptidase by the recombinant Bacillus subtilis strain AJ73 bearing the Bacillus intermedius 3-19 glutamyl endopeptidase gene within a multicopy plasmid. Optimal concentrations of the main nutrients, peptone and inorganic phosphate, were found using a multifactor approach. To provide for active growth and efficient glutamyl endopeptidase production, the cultivation medium of the recombinant strain should be enriched in phosphorus, organic and inorganic nitrogen sources, and yeast extract. Complex protein substrates, such as casein and gelatin, enhanced the biosynthesis of glutamyl endopeptidase. At the same time, easily metabolizable carbon sources suppressed it. The production of glutamyl endopeptidase was stimulated by the bivalent cations Ca2+, Mg2+, and Co2+. © 2000 MAIK "Nauka/Interperiodica"

The expression of the serine proteinase gene of Bacillus intermedius in Bacillus subtilis

The gene encoding for Bacillus intermedius serine proteinase was cloned and the complete nucleotide sequence was determined. Gene expression was explored in the protease-deficient strain Bacillus subtilis AJ73 during different stages of growth. Catabolite repression involved in control of proteinase expression during transition state and onset of sporulation was not efficient at the late stationary phase. Salt stress leads to induction of serine proteinase production during B. subtilis AJ73(pCS9) post-exponential growth. Expression of proteinase in B. subtilis deg-mutants may be controlled by DegU regulator. B. subtilis spo0-mutants failed to accomplish B. intermedius proteinase production. These data suggest complex network regulation of B. intermedius serine proteinase expression, including the action of spo0, degU, catabolite repression and demonstrate changes in control of enzyme biosynthesis at different stages of growth. © 2006 Elsevier GmbH. All rights reserved

Behavioral and Immune Responses to Infection Require Gαq- RhoA Signaling in C. elegans

Following pathogen infection the hosts' nervous and immune systems react with coordinated responses to the danger. A key question is how the neuronal and immune responses to pathogens are coordinated, are there common signaling pathways used by both responses? Using C. elegans we show that infection by pathogenic strains of M. nematophilum, but not exposure to avirulent strains, triggers behavioral and immune responses both of which require a conserved Gαq-RhoGEF Trio-Rho signaling pathway. Upon infection signaling by the Gαq pathway within cholinergic motorneurons is necessary and sufficient to increase release of the neurotransmitter acetylcholine and increase locomotion rates and these behavioral changes result in C. elegans leaving lawns of M. nematophilum. In the immune response to infection signaling by the Gαq pathway within rectal epithelial cells is necessary and sufficient to cause changes in cell morphology resulting in tail swelling that limits the infection. These Gαq mediated behavioral and immune responses to infection are separate, act in a cell autonomous fashion and activation of this pathway in the appropriate cells can trigger these responses in the absence of infection. Within the rectal epithelium the Gαq signaling pathway cooperates with a Ras signaling pathway to activate a Raf-ERK-MAPK pathway to trigger the cell morphology changes, whereas in motorneurons Gαq signaling triggers behavioral responses independent of Ras signaling. Thus, a conserved Gαq pathway cooperates with cell specific factors in the nervous and immune systems to produce appropriate responses to pathogen. Thus, our data suggests that ligands for Gq coupled receptors are likely to be part of the signals generated in response to M. nematophilum infection

Serotonergic chemosensory neurons modify the <i>C. elegans</i> immune response by regulating G-protein signaling in epithelial cells

The nervous and immune systems influence each other, allowing animals to rapidly protect themselves from changes in their internal and external environment. However, the complex nature of these systems in mammals makes it difficult to determine how neuronal signaling influences the immune response. Here we show that serotonin, synthesized in Caenorhabditis elegans chemosensory neurons, modulates the immune response. Serotonin released from these cells acts, directly or indirectly, to regulate G-protein signaling in epithelial cells. Signaling in these cells is required for the immune response to infection by the natural pathogen Microbacterium nematophilum. Here we show that serotonin signaling suppresses the innate immune response and limits the rate of pathogen clearance. We show that C. elegans uses classical neurotransmitters to alter the immune response. Serotonin released from sensory neurons may function to modify the immune system in response to changes in the animal's external environment such as the availability, or quality, of food

Isolation, characterization and complete nucleotide sequence of a novel temperate bacteriophage Min1, isolated from the nematode pathogen Microbacterium nematophilum.

We report the discovery, properties and complete sequence (46,365bp) of Min1, the first bacteriophage to be reported for the coryneform genus Microbacterium. This temperate phage is normally integrated into a stable plasmid, pMN1, found in cells of Microbacterium nematophilum, a pathogen of certain soil nematodes including Caenorhabditis elegans, but it can also grow lytically. The phage is lambdoid in morphology and in sequence, belonging to the family Siphoviridae. General and specific features of the genome are discussed, together with possible contributions of the phage to host virulence

Optimization of Bacillus intermedius glutamyl endopeptidase production by recombinant strain of Bacillus subtilis and localization of glutamyl endopeptidase in Bacillus subtilis cells

The biosynthesis of glutamyl endopeptidase from Bacillus intermedius 3-19 in recombinant strain of Bacillus subtilis has been investigated. The composition of culture medium, which yielded the maximum glutamyl endopeptidase production by B. subtilis strain, was developed, employing response surface methodology. The pathways of regulation of glutamyl endopeptidase synthesis in recombinant strain in general were found to be similar to those of other serine proteinases and of glutamyl endopeptidase in B. intermedius. Biosynthesis of glutamyl endopeptidase by recombinant strain was suppressed by easily metabolizable carbon sources. Ions of Ca2+(2mM), Mg2+ (1mM), and Co2+ (5mM) stimulated production of the proteinase by B. subtilis. In case of Co2+ ions strong stimulating effect (up to 400%) possibly was due to the release of the membrane-bound enzyme into the culture liquid, according to the mechanism described earlier for B. intermedius. The addition of Fe2+, Zn2+, and Cu2+ to the medium at concentrations of 1 to 10mM led to the gradual decrease in proteinase production by B. subtilis. This study has demonstrated a requirement by recombinant strain for excess carbon, nitrogen, and inorganic phosphate for active glutamyl endopeptidase production. In contrast with B. intermedius, for the maximum yield of endopeptidase by B. subtilis the presence in the culture medium of yeast extract at concentration of 2% and one of the organic substrates of proteinase - casein or gelatin (1%) was found to be necessary. Our study has revealed the changes in the pathways of secretion of glutamyl endopeptidase of B. intermedius by B. subtilis cells, expressing the gene for glutamyl endopeptidase from the plasmids: the part of the enzyme (2-5%) remained bound to the cell wall. © 2002 Elsevier Science Inc. All rights reserved

Optimization of Bacillus intermedius glutamyl endopeptidase production by recombinant strain of Bacillus subtilis and localization of glutamyl endopeptidase in Bacillus subtilis cells

The biosynthesis of glutamyl endopeptidase from Bacillus intermedius 3-19 in recombinant strain of Bacillus subtilis has been investigated. The composition of culture medium, which yielded the maximum glutamyl endopeptidase production by B. subtilis strain, was developed, employing response surface methodology. The pathways of regulation of glutamyl endopeptidase synthesis in recombinant strain in general were found to be similar to those of other serine proteinases and of glutamyl endopeptidase in B. intermedius. Biosynthesis of glutamyl endopeptidase by recombinant strain was suppressed by easily metabolizable carbon sources. Ions of Ca2+(2mM), Mg2+ (1mM), and Co2+ (5mM) stimulated production of the proteinase by B. subtilis. In case of Co2+ ions strong stimulating effect (up to 400%) possibly was due to the release of the membrane-bound enzyme into the culture liquid, according to the mechanism described earlier for B. intermedius. The addition of Fe2+, Zn2+, and Cu2+ to the medium at concentrations of 1 to 10mM led to the gradual decrease in proteinase production by B. subtilis. This study has demonstrated a requirement by recombinant strain for excess carbon, nitrogen, and inorganic phosphate for active glutamyl endopeptidase production. In contrast with B. intermedius, for the maximum yield of endopeptidase by B. subtilis the presence in the culture medium of yeast extract at concentration of 2% and one of the organic substrates of proteinase - casein or gelatin (1%) was found to be necessary. Our study has revealed the changes in the pathways of secretion of glutamyl endopeptidase of B. intermedius by B. subtilis cells, expressing the gene for glutamyl endopeptidase from the plasmids: the part of the enzyme (2-5%) remained bound to the cell wall. © 2002 Elsevier Science Inc. All rights reserved