El sistema SOS és una xarxa multigènica controlada negativament per la proteïna LexA, i està format per un conjunt de gens implicats en el manteniment de la viabilitat cel·lular davant de lesions en el DNA. Aquest sistema es troba en la majoria d'espècies bacterianes, malgrat que existeixen diferències tant en la seqüència d'unió de la proteïna LexA, com en el contingut genètic del reguló. En la present memòria es descriu el sistema SOS de Pseudomonas putida, un bacteri gramnegatiu pertanyent al grup Gamma. Primerament s'han clonat els dos gens lexA, anomenats lexA1 i lexA2, i s'han obtingut els seus productes gènics mitjançant sobreexpressió i purificació per columnes d'afinitat. Ambdues proteïnes s'han utilitzat en assaigs de mobilitat electroforètica (EMSA) amb els promotors de cada un dels gens lexA. Així s'ha pogut identificar la seqüència d'unió de la proteïna LexA1 (CTGTN8ACAG) i de la proteïna LexA2 (AGTACN4GTGCT). Posteriorment, utilitzant RT-PCR, s'ha vist com el gen lexA2 constitueix una única unitat transcripcional amb els gens que el segueixen, formant el casset lexA2-imuA-imuB-dnaE2. Aquest casset s'ha vist que és induïble per danys en el DNA, i que es troba àmpliament distribuït en el domini Bacteria. Seguidament, s'han obtingut dues soques mutants defectives pels gens lexA1 i lexA2, i s'ha analitzat l'expressió gènica de cada una d'elles, respecte la soca salvatge, utilitzant xips de DNA (microarrays). Els resultats obtinguts han demostrat que la proteïna LexA1 controla la majoria de gens del sistema SOS, que a més corresponen amb la resposta convencional del seu grup filogenètic; mentre que la proteïna LexA2 només regula l'expressió de la seva pròpia unitat transcripcional, i la d'un gen (PP3901) pertanyent a un profag resident de P. putida. A més, aquest gen també es troba controlat per la proteïna LexA1, essent l'únic que comparteix les dues regulacions. L'obtenció d'un mutant defectiu pel gen PP3901 ha demostrat que l'expressió d'aquest és necessària per a la transcripció dels gens del profag resident. L'expressió d'aquest profag, però, no origina cap efecte deleteri apreciable sobre el creixement de P. putida. / The SOS system is a multigenic network negatively controlled by the LexA protein, and is composed of a set of genes involved in maintaining cell viability against DNA lesions. This system is present in most bacterial species, despite the existence of differences in the binding sequence of the LexA protein, and in the genetic content of regulon. The present report describes the SOS system of Pseudomonas putida, a Gram negative bacteria belonging to the Gamma proteobacteria group. Firstly we have cloned the two lexA genes, called lexA1 and lexA2 and we have obtained their genetic products through gene overexpression and purification by affinity columns. Both proteins have been used in electroforetic mobility shift assays (EMSA) with the promoters of each of the lexA genes. By this way we could identify the recognition sequence of the LexA1 protein (CTGTN8ACAG) and the LexA2 protein (AGTACN4GTGCT). Subsequently, using RT-PCR, we could see that the lexA2 gene forms a single transcriptional unit with the genes that follow it, forming the cassette lexA2-imuA-imuB-dnaE2. This cassette has been seen that is inducible by DNA damage, and that it is present in many Proteobacteria families. Then, we constructed two defective mutant strains of lexA1 and lexA2 genes, and their gene expression has been analyzed using DNA chips (microarrays). The results have shown that the LexA1 protein controls most of the SOS genes, which also correspond with the conventional response of its phylogenetic group; while LexA2 protein only regulates its own transcriptional unit expression, and a gene (PP3901) belonging to a resident P. putida prophage. In addition, this gene is also controlled by the LexA1 protein, being the only one who shares the two regulations. The construction of a PP3901 defective strain, dempnstrated that the expression of this gene is required for the transcription of the resident prophage genes. However, the expression of the prophage genes, do not cause any significant deleterious effect on the growth of P. putida.

No description available.

Techn. Universiẗat, Diss., 2001--Braunschweig.

Universiẗat, Diss., 2002--Stuttgart.

Proefschrift Rijksuniversiteit Groningen. / Met lit.opg. - Met samenvatting in het Nederlands.

No description available.

The complete nucleotide sequence of the region encoding the DHCDH function of the pDK1 lower operon was determined. DNA analysis has shown the presence of two open reading frames, one gene consisting of 777 nucleotides encoding a polypeptide of 27.85 kDa and another gene of 303 nucleotides encoding a polypeptide of 11.13 kDa. The results of enzymatic expression studies suggest that DHCDH activity is associated only with xy1L. However although the addition of xy1T cell-free extracts to xy1L cell-free extracts does not produce an increase in DHCDH activity, subclones carrying both xy1L and xy1T exhibit 300- 400% more DHCDH activity than subclones carrying only xy1L.

Biofertilizer (or microbial soil inoculants) may be used to reduce current fertilizer inputs (organic or conventional methods), while maintaining or improving crop plant growth and yield. Pseudomonas putida is a plant-growth promoting rhizobacterium (PGPR) that solubilizes inorganic phosphorous or mineralizes organic phosphates, produces siderophores (enhancing Fe availability for plants, reducing Fe access to pathogenic fungi), and is known to improve plant growth by assisting with nutrient availability, synthesis of plant hormones (indole acetic acid regulation production and/or degradation, or ethylene regulation through aminocyclopropane carboxylate deaminase activity), and acts as a biological control of several plant pathogens and pests (Rhizoctonia solani, Bemisia tabaci). Recommendations for inoculum population density, application timing, and species of PGPR, vary mainly based on geographic and weather conditions, and their relationship to each horticultural crop, which needs to be better understood. Two studies were conducted in 2014 and 2015 at the Southern Illinois Horticulture Research Center to determine the optimum application timing and dosage of Pseudomonas putida strains 17-29 and G11-32 to improve plant growth and yield on two important horticultural crops: field grown ‘Revolution’ bell peppers and greenhouse grown ‘Rocky Top’ determinate tomatoes. Field pepper results indicated that the inoculum population density increased early-season vigor, plant height and stem caliper (P < 0.05), as well as late-season plant vigor, height (cm), leaf chlorophyll index (SPAD), and stem caliper (mm) (P < 0.05) for inoculum population density. Although early harvests (first two harvests) fruit yield increased with rhizobacteria inoculum population density (P < 0.05) for total fruit weight (2014, 2015) and number (2014), late-season fruit yields (last three harvests) were not affected. Combined fruit yield total weight (all five harvests) also increased (P < 0.05) by inoculum population density in the order: 10^0 < 10^3 < 10^5 < 10^7 < 10^9. It appears that higher early-season and combined harvest yields were higher resulting from increasing inoculum population densities were greater due to increased early season growth from the bacterial treatments during plug growth phase. Tomato results indicated that inoculum population density increased early growth and late growth vigor, height (cm), leaf chlorophyll index (SPAD), leaf number, flower number, fresh leaf weight (g), fresh stem weight, and dry leaf weight (P < 0.05). Tomato growth was effected by inoculum population density treatment however, yields differences were not observed.

No description available.

Aspartate transcarbamoylase (ATCase) is encoded by the pyrBI genes in E. coli. Expression of these genes is reduced four-fold by attenuation when grown on uracil. Using plasmid, pRO1727. the pyrB and the pyrBI genes from E. coli were cloned into a P. putida pyrB auxotroph. A recombinant pyrB gene was recovered that encoded a functional hybrid ATCase with a molecular weight of 470 kDa.