Clonostachys chloroleuca: A novel pathogen causing cassava root rot disease in Misiones Province, Argentina

Cassava (Manihot esculenta) is a crucial food source facing a threat from Cassava Root Rot Disease (CRRD), often caused by fungi like Fusarium, Lasiodiplodia, Phytophthora, among others. In this study, roots from cassava plants displaying CRRD symptoms were collected in Argentina. The isolated fungus, identified as Clonostachys chloroleuca through morphological and molecular methods, was confirmed as the cause of CRRD. In vitro severity tests revealed a high severity value of 22%. The fungus exhibited vigorous growth on root surfaces, causing deep dark coloration and dry pulp consistency. In vivo assays on cassava plants supported the manifestation of typical CRRD symptoms. This study marks the first report of C. chloroleuca causing CRRD, emphasizing its potential threat to cassava production. Further research is essential to understand its pathogenic mechanisms and validate findings in real-world conditions.Fil: Madrassi, Lucas Martín. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentina. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Departamento de Bioquímica Clinica; ArgentinaFil: Gonzalez, R. D.. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Departamento de Bioquímica Clinica; ArgentinaFil: Mónaco, C. I.. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Departamento de Bioquímica Clinica; ArgentinaFil: Zapata, Pedro Dario. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Departamento de Bioquímica Clinica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; ArgentinaFil: Alvarenga, Adriana Elizabet. Universidad Nacional de Misiones. Facultad de Cs.exactas Químicas y Naturales. Departamento de Bioquímica Clinica; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste; Argentin

Biocontrol de la mancha de la hoja del trigo con aislamientos de Trichoderma spp.

La mancha de la hoja de trigo, causada por Mycosphaerella graminicola (Fuckel) Schroeter, in Cohn (anamorfo Septoria tritici) es una importante enfermedad en muchas areas productoras de trigo del mundo. Diversos factores están modificando las tácticas de manejo tradicional de la enfermedades, orientandolas hacia una mayor dependencia de los métodos de control cultural y biológico en detrimento del uso de pesticidas. Entre los agentes antagonistas, Trichoderma spp. se utilizo con buenos resultados como biocontrolador de patógenos de plantas crucíferas, solanaceas y gramineas. Un aislamiento de T.harzianum biocontrolo S.tritici bajo condiciones in vitro y de invernáculo, (Perello, et al., 1997). El objetivo de este trabajo fue evaluar y comparar la severidad de la mancha de la hoja del trigo en plantas inoculadas con el patógeno y en plantas previamente tratadas con las especies de Trichoderma

Amyloid formation modulates the biological activity of a bacterial protein

The aggregation of proteins into amyloid fibrils is the hallmark feature of a group of late-onset degenerative diseases including Alzheimer, Parkinson, and prion diseases. We report here that microcin E492, a peptide naturally produced by Klebsiella pneumoniae that kills bacteria by forming pores in the cytoplasmic membrane, assembles in vitro into amyloid-like fibrils. The fibrils have the same structural, morphological, tinctorial, and biochemical properties as the aggregates observed in the disease conditions. In addition, we found that amyloid formation also occurs in vivo where it is associated with a loss of toxicity of the protein. The finding that microcin E492 naturally exists both as functional toxic pores and as harmless fibrils suggests that protein aggregation into amyloid fibrils is an evolutionarily conserved property of proteins that can be successfully employed by bacteria to fulfill specific physiological needs

Endovascular Treatment of Superior Vena Cava Syndrome in the Immediate Postoperative Period of Heart Transplantation

El trasplante cardíaco está indicado en pacientes con insuficiencia cardíaca terminal sin opción de tratamiento médico, intervencionista o quirúrgico y puede realizarse utilizando fundamentalmente tres variantes técnicas. El beneficio de la técnica bicava en términos de parámetros hemodinámicos y clínicos la ha convertido en la más utilizada, aunque es técnicamente más demandante y puede tener algunas consecuencias, como estenosis en las anastomosis de las venas cavas. (resumen completo en pdf

Leptin increases prostate cancer aggressiveness

Recent studies indicate that adipose tissue and adipocytokines might affect the development of prostate cancer (PCa). Leptin would have a stimulating effect on prostate cancer cells by inducing promotion and progression, whereas adiponectin would have a protective effect. The aim of this study was to determine the relation between body composition, leptin, and adiponectin levels with the prevalence and aggressiveness of PCa in men of Mendoza, Argentina. Seventy volunteers between 50 and 80 years (35 healthy men as control group and 35 with PCa) were selected. The PCa group was subclassified according to the Gleason Score (GS). Digital rectal examination, transrectal ultrasound, and prostatic biopsy were performed; PSA, testosterone, leptin, and adiponectin levels were determined; and a nutritional interview including anthropometric measurements and a food frequency questionnaire was carried out. Statistical analysis was performed by Student t test, ANOVA I, and Bonferroni (p < 0.05). Body mass index and percentage of body fat mass were not statistically different between PCa and control groups. However, body fat mass was higher in subjects with more aggressive tumors (p = 0.032). No differences were observed regarding leptin levels between the groups. Nevertheless, leptin levels were higher in subjects with high GS (p < 0.001). Adiponectin levels showed no statistical differences regarding the presence and aggressiveness of the tumor (p = 0.131). Finally, consumption and nutrient intake did not differ in the studied groups. In conclusion, body composition and leptin are related to the PCa aggressiveness but not with its prevalence.Fil: López Fontana, Constanza Matilde. Universidad "Juan Agustín Maza"; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; ArgentinaFil: Maselli, María Eugenia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto de Medicina y Biología Experimental de Cuyo; Argentina. Universidad "Juan Agustín Maza"; ArgentinaFil: Pérez Elizalde, Rafael F.. Laboratorio de Alta Complejidad Pérez Elizalde; Argentina. Universidad "Juan Agustín Maza"; ArgentinaFil: Di Milta Mónaco, Nicolás A.. Universidad "Juan Agustín Maza"; ArgentinaFil: Uvilla Recupero, Ana L.. Universidad "Juan Agustín Maza"; ArgentinaFil: López Laur, José D.. Universidad "Juan Agustín Maza"; Argentina. Universidad Nacional de Cuyo. Facultad de Ciencias Médicas; Argentin

Trichoderma spp. as elicitors of wheat plant defense responses against Septoria tritici

Leaf blotch of wheat is a widespread and highly active disease that affects wheat production. In addition to the use of chemicals and proper cultivation methods, microbial antagonists are used to control plant pathogens. Trichoderma spp. stimulate a systemic induced response in plants. Therefore, the efficacy of Trichoderma spp. against wheat leaf blotch was evaluated under greenhouse conditions. The susceptible plants were sprayed with Septoria tritici conidiospores. In order to select an efficient method of pretreatment with Trichoderma spp., leaf spraying and seed coating with 14 isolates were tested in 2003 and 2004. The extent of leaf necrosis area and pycnidial coverage was estimated. Antagonism was assessed by the capacity of each Trichoderma spp. isolate to restrict the progress of leaf blotch, 21 days after inoculation. Of the two methods, seed coating was more efficacious against leaf blotch than leaf spraying. Amongst the 14 isolates tested, the isolate prepared from T. harzianum (Th5) produced the highest level of protection. None of the treatments caused changes in plant stem diameter or dry weight. Trichoderma spp. did not get into leaves while S. tritici was present, even in asymptomatic leaf extracts. In addition, the leaf apoplast antifungal proteolytic activity was measured in plants 7, 15, and 22 days after sowing. This antifungal action decreased in plants only inoculated with S. tritici, but increased in those grown from seeds coated with the T. harzianum (Th5) isolate. This increase conferred resistance to the susceptible wheat cultivar. The endogenous germin-like protease inhibitor coordinated the proteolytic action. These results suggest that T. harzianum stimulates a biochemical systemic induced response against leaf blotch

Bacterial tubulins A and B exhibit polarized growth, mixed-polarity bundling, and destabilization by GTP hydrolysis

Bacteria of the genus Prosthecobacter express homologs of eukaryotic alpha- and beta-tubulin, called BtubA and BtubB (BtubA/B), that have been observed to assemble into filaments in the presence of GTP. BtubA/B polymers are proposed to be composed in vitro by two to six protofilaments in contrast to that in vivo, where they have been reported to form 5-protofilament tubes named bacterial microtubules (bMTs). The btubAB genes likely entered the Prosthecobacter lineage via horizontal gene transfer and may be derived from an early ancestor of the modern eukaryotic microtubule (MT). Previous biochemical studies revealed that BtubA/B polymerization is reversible and that BtubA/B folding does not require chaperones. To better understand BtubA/B filament behavior and gain insight into the evolution of microtubule dynamics, we characterized in vitro BtubA/B assembly using a combination of polymerization kinetics assays and microscopy. Like eukaryotic microtubules, BtubA/B filaments exhibit polarized growth with different assembly rates at each end. GTP hydrolysis stimulated by BtubA/B polymerization drives a stochastic mechanism of filament disassembly that occurs via polymer breakage and/or fast continuous depolymerization. We also observed treadmilling (continuous addition and loss of subunits at opposite ends) of BtubA/B filament fragments. Unlike MTs, polymerization of BtubA/B requires KCl, which reduces the critical concentration for BtubA/B assembly and induces it to form stable mixed-orientation bundles in the absence of any additional BtubA/B-binding proteins. The complex dynamics that we observe in stabilized and unstabilized BtubA/B filaments may reflect common properties of an ancestral eukaryotic tubulin polymer. IMPORTANCE Microtubules are polymers within all eukaryotic cells that perform critical functions; they segregate chromosomes, organize intracellular transport, and support the flagella. These functions rely on the remarkable range of tunable dynamic behaviors of microtubules. Bacterial tubulin A and B (BtubA/B) are evolutionarily related proteins that form polymers. They are proposed to be evolved from the ancestral eukaryotic tubulin, a missing link in microtubule evolution. Using microscopy and biochemical approaches to characterize BtubA/B assembly in vitro, we observed that they exhibit complex and structurally polarized dynamic behavior like eukaryotic microtubules but differ in how they self-associate into bundles and how this bundling affects their stability. Our results demonstrate the diversity of mechanisms through which tubulin homologs promote filament dynamics and monomer turnover.Fondecyt 1095121 1130711 CONICYT MECESUP UCH0604 NS