BACTERIA

Author: RUZ ESTÉVEZ LÍDIA.
Year: 2003.
University: GIRONA [www.udg.es].
Place of defense: ESCUELA POLITÉCNICA SUPERIOR.
Place of preparation: UNIVERSIDAD DE GIRONA.

Author: Jurado Lobo Valme.
Year: 2004.
University: SEVILLA [www.us.es].
Place of defense: Instituto de Recursos Naturales y Agrobiología.
Place of preparation: Facultad de Biología.

Summary: In recent years he has devoted special attention to the processes of biodeterioration arising from the growth of microorganisms in environments hypogea. The environments are hypogea consist of caves, cemeteries and catacombs. They are characterized by relatively low temperatures and submit constant throughout the year, high relative humidity, being relatively poor in nutrients and organic dimly lit present or absent, except in those places where there is artificial lighting systems. The lighting systems are conducive to the development of biofilms consist mainly by microorganisms fototrofos as cyanobacteria, which also supports the growth of microorganisms hetrotrofos, such as bacteria and fungi. Using isolation techniques based on physiological and biochemical tests, together with molecular techniques based on the amplification of DNA, usually in ARNr 16S has been shown to the high diversity of microorganisms in environments hypogea. The microorganisms grown more abundant in these environments are Actinobacterias, processes involved in biodeterioration of paintings and works of art. Within the group of Actinobacterias emphasizes the presence of gender Agromyces so far linked to different environments of hypogea. The objective of this thesis is to make a taxonomic revision of the genus Agromyces and description of new species isolated environments hypogea. The testing polifásicas (phenotypic and genotypic testing) has enabled the description of 7 new species of the genus Agromyces (A. hippuratus, A. neolithicus, A. salentinus, A. italicus, A. humatus, A. lapidis and A. subbeticus ) and redescripción kind of type A. Fucosus. This has meant an increase in the number of species, ranging from 10 species start to the 17 existing, representing 47% of the total, suggesting the wide distribution of gender in most ecosystems than has been known. In addition, in order to know the role of gender Agromyces in biogeochemical cycles of environments hypogea were conducted experiments bioinducción crystals in the lab using different culture media and strains Agromyces caves and catacombs. The results showed that species Agromyces are capable of inducing precipitation of calcium, magnesium and barium in the laboratory, suggesting the importance of species of the genus Agromyces processes biomineralización typical environments hypogea of cultural interest.

Author: CARUSO PAOLA.
Year: 2005.
University: VALENCIA [www.uv.es].
Place of defense: FACULTAD DE FARMACIA - UNIVERSITAT DE VALÈNCIA.
Place of preparation: UNIVERSITAT DE VALÈNCIA.

Summary: The brown rot in potatoes or marchitez is a bacterial disease that causes significant economic losses in the cultivation of Solanaceae. It is caused by the bacterium Ralstonia solanacearum, considered quarantine in the European Union (EU), but its presence has already been officially declared in several European countries, including Spain having increased its practical significance in the past 10 years. The bacterium is classified in five races and six biovares as the host range and the ability to use oxidize sugars and alcohols. Given the lack of knowledge about the characteristics of the Spanish strains analyzed and studied through techniques biochemical, serological and molecular, a collection of them, from different origins. It was confirmed that all strains belonged to biovar 2. Its biochemical characteristics were homogeneous, whereas using serological and molecular techniques, showed some variability between them. Due to the dispersion of the disease is through the spread of plant material asymptomatic and irrigation water, were also on the verge serological and molecular methods of routine use for the sensitive and specific detection of R. Solanacearum. The serological detection protocol developed was based on the technique ELISA-DASI with monoclonal antibodies and prior enrichment. The detection limit of R. Solanacearum from samples of potato was 1-10 cfu / ml of extract potato (Caruso et al., 2002). The molecular detection method was based on the use of cooperative PCR and hybridization with specific and subsequent probe revealed color, to improve detection and facilitate its application in routine. This method was very sensitive and enabled the detection of up to a cell of R. Solanacearum, without extracting DNA from the sample (Caruso et al., 2003). The techniques developed have proved effective even in the detection of cell stress and viable state but not arable (VBNC) of R. Solanacearum. Prospecting for three years on the River Tormes (Salamanca), studied the seasonal variability of the bacterium and its behavior depending on the different environmental and climatic conditions. It showed variation estaciónal of the population of R. Solanacearum in the waters of the river Tormes, associated especially with the drop in temperature. It was also found that when the temperature dropped below 14Â ° C bacteria entered the VBNC state, and indeed the direct isolation of R. Solanacearum was only possible to water temperatures higher than 14Â ° C. Also for the first time the method was applied most probable number (MPN) to the detection and quantification of cell stress of R. Solanacearum. Applying this technique, were isolated cells that had lost the cultivabilidad amid solid since more than 25 days (Caruso et al., 2005). The inoculations tomato plants in stressed cells isolated from the river showed that they were capable of causing infections, while VBNC seemed almost completely lose their virulence (Caruso et al., 2005). Techniques developed and the information on the characteristics of the strains of R. Solanacearum isolated in Spain and its epidemiology, will contribute to better understanding and control of the disease.

Author: Maggiorani Valecillos Alfredo Emilio.
Year: 2005.
University: POLITÉCNICA DE MADRID [www.upm.es].
Place of defense: E.T.S. de Ingenieros Agrónomos.
Place of preparation: E.T.S. Ingenieros Agrónomos.

Summary: Two important aspects were studied in the plant pathogen interaction. One has been the study of the bacterial disease resistance in potato, which are based on the production of toxic substances from the plant. The most important results were: an inhibitor was isolated from trypsin and chymotrypsin of potato tuber of the variety Arbolona Black, called AN-PinII. It is active in vitro, in concentrations of 100 Â µ g / ml, compared with the bacteria fitopatógena Ralstonia solanacearum, describing for the first time the antimicrobial activity of this protein in a bacterium fitopatógena. The presence of this inhibitor (AN-PinII) in tissues of the cell wall of potato tubers, plays an important role in the formation of barriers to defend against the attack of bacterial pathogens as R. Solanacearum. These findings will address studies in plant expression in order to corroborate the results obtained with this inhibitor. Another study was the analysis of genes involved in various functions of MDR bacteria fitopatógena Erwinia chrysanthemi. The most important results were: were selected 9 gene homologues systems MDRs of several identified in the genome of the bacterium. They were selected by two systems with bioinformatics methods similar to a bomb transport Acr (family RND), two systems similar to the bomb Emr (MFS family), and another candidate (Mlr) belonging to the family MFS. We cloned and corresponding mutants were constructed in E. Chrysanthemi, for the effect on pathogenicity of these mutations. The virulence tests were carried out on sheets African violet (Saintpaulia ionantha) and endive leaves (Cichorium intybus L. var. Foliosum). The mutants presented different levels of susceptibility to toxic substances, as well as varying degrees of virulence depending on the host. All results indicate that mutations in different systems MDR affect the virulence of different ways different hosts.

Author: NAVASCUÉS ORTEGA CARMEN BEATRIZ.
Year: 2006.
University: GRANADA [www.ugr.es].
Place of defense: FACULTAD DE CIENCIAS.
Place of preparation: ESTACIÓN EXPERIMENTAL DEL ZAIDÍN, CSIC-GRANADA.

Summary: While classic has been considered the microorganism as isolated individuals who do not interact with each other, it has demonstrated its ability to communicate through chemical compounds. At intercellular communication system that regulates the expression of a set of genes specialized in response to the density of their populations is called quorum-sensing or perception of a quorum. Bradyrhizobium japonicum is the microsimbionte of soybeans (Glycine-max). Since it has been shown that the genes of nodulation in this bacterium could be controlled by perception of a quorum and considering that were unknown genes involved in the production of autoinductores, in this paper we develop the following objectives: 1Â º identification and regulation of genes involved in producing autoinductores in Bradyrhizobium japonicum. 2 Â º Study of the effect of the inoculation of soybean plants inoculated with strains of Bradyrhizobium japonicum involved in the production

Author: QUESADA PÉREZ JOSÉ MIGUEL.
Year: 2006.
University: POLITÉCNICA DE VALENCIA [www.upv.es].
Place of defense: Universidad Politécnica de Valencia.
Place of preparation: Universidad Politécnica de Valencia.

Summary: Pseudomonas savastanoi pv. Savastanoi (Psv) is the causative agent of tuberculosis olive characterized by the formation of tumors in different parts of the tree. Although the disease is prevalent in most countries of the Mediterranean, there are few studies on the epidemiology of the disease in Spain, as well as their chemical control. Moreover, the molecular characterization of the isolated Psv has great potential value for basic and epidemiological studies. A worldwide collection of isolated Psv tumor olive, was analyzed to determine the distribution, variation in the positions and number of copies of element insertion IS53. Analysis of genetic diversity based on the profiles IS53-RFLP has allowed grouping different strains Psv isolated olive and groups do not appear to be associated with geographic origin in the isolated Spaniards. Because of its presence in all strains of Psv, high stability shown both in vitro and in vivo and its high degree of polymorphism, typing through IS53-RFLP is an excellent tool for future epidemiological studies on tuberculosis olive. Due to the limited information available on stocks epiphytes of Psv in naturally infected trees in plots Spanish, was an appropriate methodology for the analysis of populations Psv in outbreaks without symptoms of infected trees naturally, for three consecutive years. Psv has shown in infected plants uneven distribution between sheets of the same outbreak, epiphytes populations may vary by several orders of magnitude between different leaves. Psv had colonized in infected plants, stalks and leaves showing low population averages. Stocks epiphytes of Psv have shown a clear seasonal variation in the climatic parameters that can have a major influence.