Abscisic acid (ABA) is involved in seed development and plant adaptation to environmental stresses. ABA synthesized from cleaved xanthophylls zeaxanthin epoxidase (ZEP) the enzyme responsible for conversion of violaxanthin. In this study, we have characterized ABA1 gene (AtZEP) Arabidopsis thaliana L. show that complements aba1 mutant, defective epoxidation. The molecular basis two mutant alleles has been determined reduction their AtZEP transcript levels correlates with defect identified....

Cyanobacteria can utilize nitrate or ammonium as a source of fixed nitrogen for cell growth. In the filamentous Calothrix sp. strain PCC 7601, these two sources differently influenced phycobiliprotein composition phycobilisomes, major light-harvesting antennae. When compared to nitrate, growth in presence resulted intracellular steadystate levels 35% lower phycoerythrin and 46% higher phycocyanin. Besides differences pigmentation, rapid but transient accumulation cyanophycin granule...

Using degenerate primers designed by deduced amino acid sequences of known aldehyde oxidases (AO) from maize and bovine, two independent cDNA fragments were amplified reverse transcription-polymerase chain reaction (PCR). The corresponding full-length cDNAs (atAO-1 atAO-2; 4,484 4,228 bp long, respectively) cloned screening the Arabidopsis library followed rapid amplification end-PCR. These are highly homologous at both nucleotide sequence levels, showed high similarity with those tomato...

In the absence of a tight control copper entrance into cells, bacteria have evolved different systems to concentration within cytoplasm and periplasm. Central these systems, Cu(+) ATPase CopA plays major role in tolerance translocates from The fate periplasm varies among species. Copper can be sequestered, oxidized, or released outside cells. Here we describe identification CopI, periplasmic protein present many proteobacteria, show its requirement for Rubrivivax gelatinosus. ΔcopI mutant is...

The appearance of oxygen in the Earth's atmosphere via oxygenic photosynthesis required strict anaerobes and obligate phototrophs to cope with presence this toxic molecule. Here we show that anoxygenic phototroph Rubrivivax gelatinosus, terminal oxidases (cbb(3), bd, caa(3)) expand range ambient tensions under which organism can initiate photosynthesis. Unlike wild type, cbb(3)(-)/bd(-) double mutant start only deoxygenated medium or when is removed, either by sparging cultures nitrogen...

Silver (Ag+) and copper (Cu+) ions have been used for centuries in industry, as well antimicrobial agents agriculture health care. Nowadays, Ag+ is also widely the field of nanotechnology. Yet, underlying mechanisms driving toxicity vivo are poorly characterized. It known that exposure to excess metal impairs photosynthetic apparatus plants algae. Here, we show light-harvesting complex II (LH2) primary target Cu+ purple bacterium Rubrivivax gelatinosus specifically inactivate 800-nm...

Cadmium, although not redox active is highly toxic. Yet, the underlying mechanisms driving toxicity are still to be characterized. In this study, we took advantage of purple bacterium Rubrivivax gelatinosus strain with defective Cd2+-efflux system identify targets metal. Exposure cadA Cd2+ causes a decrease in photosystem amount and activity respiratory complexes. As case Cu+ toxicity, data indicated that porphyrin biosynthesis pathway at level HemN, S-adenosylmethionine CxxxCxxC...

Summary Pollution by copper (Cu 2+ ) extensively used as antimicrobial in agriculture and farming represents a threat to the environment human health. Finding ways make microorganisms sensitive lower metal concentrations could help decreasing use of Cu 2 + agriculture. In this respect, we showed that limiting iron (Fe) uptake makes bacteria much more susceptible or Cd poisoning. Using efflux mutants purple bacterium Rubrivivax gelatinosus, resistance relies on expression Fur‐regulated FbpABC...

Summary Heavy metal contamination is a serious environmental problem. Understanding the toxicity mechanisms may allow to lower concentration of metals in metal‐based antimicrobial treatments crops, and reduce content soil groundwater. Here, we investigate interplay between efflux systems superoxide dismutase (SOD) purple bacterium Rubrivivax gelatinosus other bacteria through analysis impact accumulation. Exposure Cd 2+ ‐efflux mutant Δ cadA caused an increase amount activity cytosolic...

Genes belonging to the same metabolic route are usually organized in operons microbial genomes. For instance, most genes involved photosynthesis were found clustered and photosynthetic Alpha- Betaproteobacteria. The discovery of Gammaproteobacteria with a conserved gene cluster revives questions on role maintenance such organization proteobacteria. In this paper, we report analysis structure expression 14 kb (crtEF-bchCXYZ-pufBALMC-crtADC) betaproteobacterium Rubrivivax gelatinosus, purpose...

The xanthine oxidoreductase (XOR) family are metal-containing enzymes that use the molybdenum cofactor (Moco), 2Fe-2S clusters, and flavin adenine dinucleotide (FAD) for their catalytic activity. This large molybdoenzyme includes xanthine, aldehyde, CO dehydrogenases. XORs widely distributed from bacteria to humans due key roles in catabolism of purines, aldehydes, drugs, xenobiotics, as well interconversions between CO2. Assessing effect excess metals on Rubrivivax gelatinosus bacterium, we...

Bacteria respond to metal pollution through sensors that control the uptake and detoxification machineries. Specificity in recognition is therefore a prerequisite for triggering appropriate response, particularly when facing mixture of metals. In response Cu+, purple bacterium Rubrivivax gelatinosus induces efflux Cu+-ATPase CopA by Cu+ regulator CopR. However, genetic analyses have suggested presence additional regulators. Here, we show CadR, Cd2+ sensor, involved tolerance demonstrate CopR...

Summary Characterization of a copA − mutant in the purple photosynthetic bacterium R ubrivivax gelatinosus under low oxygen or anaerobic conditions, as well human pathogen N eisseria gonorrhoeae identified HemN copper toxicity target enzyme porphyrin synthesis pathway. Heme is, however, unaffected by high tension because aerobic coproporphyrinogen III oxidase HemF . Nevertheless, aerobiosis, we show that chlorophyll biosynthesis pathway is affected excess resulting substantial decrease...

In the filamentous cyanobacterium Calothrix PCC 7504, which fixes N2 aerobically, modification state of regulatory PII protein (GlnB) was shown to depend on nitrogen and carbon availability, as observed in unicellular non-fixing strain Synechococcus 7942. However, conditions for modifications, time dependence process electrophoretic behavior native isoforms differed somewhat between two strains. another strain, 7601, has lost capability fix N2, modified only if ammonia plus an inhibitor...

Abstract Photosynthetic bacteria can switch from planktonic lifestyle to phototrophic biofilm in mats response environmental changes. The mechanisms of formation are, however, not characterized. Herein, we report a two‐component system EmbRS that controls the photosynthetic member Burkholderiales order, purple bacterium R ubrivivax gelatinosus . inactivation results cells form conspicuous bacterial veils and fast‐sinking aggregates liquid. Biofilm analyses indicated represses production an...

In the filamentous cyanobacterium Calothrix PCC 7504, which fixes N2 aerobically, modification state of regulatory PII protein (GlnB) was shown to depend on nitrogen and carbon availability, as observed in unicellular non-fixing strain Synechococcus 7942. However, conditions for modifications, time dependence process electrophoretic behavior native isoforms differed somewhat between two strains. another strain, 7601, has lost capability fix N2, modified only if ammonia plus an inhibitor...

Abstract The use of silver (Ag + ) as an antimicrobial under different forms and at scales, appears in numerous applications such health care, food industry, clothing, fabrics disinfectants. Yet, there is still important gaps regarding the complete comprehension mechanisms its actions on bacteria. In a previous work, we demonstrated that, copper severly damage membrane proteins involved photosynthesis respiration bacteria exposed to metal excess. Here, are presenting complementary data using...

Abstract The use of silver (Ag + ) as an antimicrobial under different forms and at scales, appears in numerous applications such health care, food industry, clothing, fabrics disinfectants. Yet, there is still important gaps regarding the complete comprehension mechanisms its actions on bacteria. In a previous work, we demonstrated that, copper severly damage membrane proteins involved photosynthesis respiration bacteria exposed to metal excess. Here, are presenting complementary data using...