Mostra DPA 2010: entre oficio y pensamiento

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Mostra DPA 2010: entre oficio y pensamiento

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Microscopic and transcriptome analyses of early colonization of tomato roots by Trichoderma harzianum

The capacity of the fungus Trichoderma harzianum CECT 2413 to colonize roots and stimulate plant growth was analyzed. Tobacco seedlings (Nicotiana benthamiana) transferred to Petri dishes inoculated with T. harzianum conidia showed increased plant fresh weight (140%) and foliar area (300%), as well as the proliferation of secondary roots (300%) and true leaves (140%). The interaction between strain CECT 2413 and the tomato-root system was also studied during the early stages of root colonization by the fungus. When T. harzianum conidia were inoculated into the liquid medium of hydroponically grown tomato plants (Lycopersicum esculentum), profuse adhesion of hyphae to the plant roots as well as colonization of the root epidermis and cortex were observed. Confocal microscopy of a T. harzianum transformant that expressed the green fluorescent protein (GFP) revealed intercellular hyphal growth and the formation of plant-induced papilla-like hyphal tips. Analysis of the T. harzianum-tomato interaction in soil indicated that the contact between T. harzianum and the roots persisted over a long period of time. This interaction was characterized by the presence of yeast-like cells, a novel and previously undescribed developmental change. To study the molecular mechanism underlying fungal ability to colonize the tomato-root system, the T. harzianum transcriptome was analyzed during the early stages of the plant-fungus interaction. The expression of fungal genes related to redox reactions, lipid metabolism, detoxification, and sugar or amino-acid transport increased when T. harzianum colonized tomato roots. These observations are similar to those regarding the interactions of mycorrhiza and pathogenic fungi with plants. [Int Microbiol 2007; 10(1):19-27

Microscopic and transcriptome analyses of early colonization of tomato roots by "Trichoderma harzianum".

The capacity of the fungus Trichoderma harzianum CECT 2413 to colonize roots and stimulate plant growth was analyzed. Tobacco seedlings (Nicotiana benthamiana) transferred to Petri dishes inoculated with T. harzianum conidia showed increased plant fresh weight (140%) and foliar area (300%), as well as the proliferation of secondary roots (300%) and true leaves (140%). The interaction between strain CECT 2413 and the tomato-root system was also studied during the early stages of root colonization by the fungus. When T. harzianum conidia were inoculated into the liquid medium of hydroponically grown tomato plants (Lycopersicum esculentum), profuse adhesion of hyphae to the plant roots as well as colonization of the root epidermis and cortex were observed. Confocal microscopy of a T. harzianum transformant that expressed the green fluorescent protein (GFP) revealed intercellular hyphal growth and the formation of plant-induced papilla-like hyphal tips. Analysis of the T. harzianum-tomato interaction in soil indicated that the contact between T. harzianum and the roots persisted over a long period of time. This interaction was characterized by the presence of yeast-like cells, a novel and previously undescribed developmental change. To study the molecular mechanism underlying fungal ability to colonize the tomato-root system, the T. harzianum transcriptome was analyzed during the early stages of the plant-fungus interaction. The expression of fungal genes related to redox reactions, lipid metabolism, detoxification, and sugar or amino-acid transport increased when T. harzianum colonized tomato roots. These observations are similar to those regarding the interactions of mycorrhiza and pathogenic fungi with plants.Comisión Europea QLK3-CT-2002-02032Ministerio de Ciencia y Tecnologia AGL2000-0524 and BIO2003-03679Junta de Andalucía PAI CVI-10

Generation, annotation and analysis of ESTs from Trichoderma harzianum CECT 2413

BACKGROUND: The filamentous fungus Trichoderma harzianum is used as biological control agent of several plant-pathogenic fungi. In order to study the genome of this fungus, a functional genomics project called "TrichoEST" was developed to give insights into genes involved in biological control activities using an approach based on the generation of expressed sequence tags (ESTs). RESULTS: Eight different cDNA libraries from T. harzianum strain CECT 2413 were constructed. Different growth conditions involving mainly different nutrient conditions and/or stresses were used. We here present the analysis of the 8,710 ESTs generated. A total of 3,478 unique sequences were identified of which 81.4% had sequence similarity with GenBank entries, using the BLASTX algorithm. Using the Gene Ontology hierarchy, we performed the annotation of 51.1% of the unique sequences and compared its distribution among the gene libraries. Additionally, the InterProScan algorithm was used in order to further characterize the sequences. The identification of the putatively secreted proteins was also carried out. Later, based on the EST abundance, we examined the highly expressed genes and a hydrophobin was identified as the gene expressed at the highest level. We compared our collection of ESTs with the previous collections obtained from Trichoderma species and we also compared our sequence set with different complete eukaryotic genomes from several animals, plants and fungi. Accordingly, the presence of similar sequences in different kingdoms was also studied. CONCLUSION: This EST collection and its annotation provide a significant resource for basic and applied research on T. harzianum, a fungus with a high biotechnological interest

All-cause mortality in the cohorts of the Spanish AIDS Research Network (RIS) compared with the general population: 1997Ł2010

Abstract Background: Combination antiretroviral therapy (cART) has produced significant changes in mortality of HIVinfected persons. Our objective was to estimate mortality rates, standardized mortality ratios and excess mortality rates of cohorts of the AIDS Research Network (RIS) (CoRIS-MD and CoRIS) compared to the general population. Methods: We analysed data of CoRIS-MD and CoRIS cohorts from 1997 to 2010. We calculated: (i) all-cause mortality rates, (ii) standardized mortality ratio (SMR) and (iii) excess mortality rates for both cohort for 100 personyears (py) of follow-up, comparing all-cause mortality with that of the general population of similar age and gender. Results: Between 1997 and 2010, 8,214 HIV positive subjects were included, 2,453 (29.9%) in CoRIS-MD and 5,761 (70.1%) in CoRIS and 294 deaths were registered. All-cause mortality rate was 1.02 (95% CI 0.91-1.15) per 100 py, SMR was 6.8 (95% CI 5.9-7.9) and excess mortality rate was 0.8 (95% CI 0.7-0.9) per 100 py. Mortality was higher in patients with AIDS, hepatitis C virus (HCV) co-infection, and those from CoRIS-MD cohort (1997. Conclusion: Mortality among HIV-positive persons remains higher than that of the general population of similar age and sex, with significant differences depending on the history of AIDS or HCV coinfection

Efecto de especies activas del oxígeno sobre el sistema asimilador del nitrato en Azotobacter chroococcum

Tesis antigu

Primary structure of Trichoderma harzianum ribosomal protein L32

Eukaryotic ribosomal proteins (rp) are found to be arranged in relatively large (8 to > 20 member) families of unlinked genes. These families are usually composed by a single intron(s)- containing expressed gene, and a number of processed, silent genes (1). One of the most studied of these families, L32, has been shown to be highly conserved among the organisms where it has been identified, i.e, mouse, human and flies (2, 3, 4, 5), but no information was available regarding the lower-eukaryote counterparts. While screening for another gene in a cDNA library from the filamentous fungus Trichoderma harzianum, we isolated a clone whose deduced amino acid sequence showed high homology (around 50% identity) with L32 rp from mouse, human, Drosophila melanogaster and D. subobscura (Figure 1). The cDNA is 562 bp in length and codes for a 137-amino-acid polypeptide. This deduced protein, termed TrpL32, is very rich in basic residues (pI = 12.41) and quite hydrophobic (data not shown) which is in agreement with the information related with the other L32 rp studied so far. From Southern analysis (data not shown) we have seen that this protein is encoded by a single gene or by several very highly homologous ones grouped in a 6 kb Hindm genomic fragment.Peer Reviewe