Control de hongos fitopatógenos de importancia agrícola utilizando como agente a Bacillus thuringiensis (Berliner)

Numerosas especies de hongos y bacterias en el mundo son conocidas por tener un efecto antagónico sobre otros microorganismos y son utilizadas por el hombre para la regulación de patógenos cuyo hábitat es el suelo. El género Bacillus, se encuentra entre los agentes más utilizados para el control biológico debido a cualidades tanto morfológicas como fisiológicas que permiten su ubicuidad en la naturaleza, además ha tenido mucho éxito en la prevención de patologías vegetales causadas por hongos. B. thuringiensis es el organismo más exitoso en cuanto a comercialización, este produce un cuerpo paraesporal, denominado δ–endotoxina, y su espectro de hospederos es muy amplio, la especificidad, virulencia, seguridad y potencia contra insectos y organismos patógenos está bien establecida, se sabe que produce una gran diversidad de metabolitos, como bacteriocinas, antibióticos y enzimas extracelulares tales como proteasas y quitinasas, elementos clave en el fenómeno de supresión de patógenos por agentes biológicos. Sin embargo, hay poca información de su potencial antifúngico. El objetivo del presente trabajo fue seleccionar cepas de B. thuringiensis con potencial antagónico para controlar hongos fitopatógenos de importancia agrícola, con la finalidad de contar con una alternativa biológica para su control y explorar otras formas para aprovechar la biodiversidad de B. thuringiensis para la protección de cultivos agrícolas. Para esto fue evalaluada 1) La actividad antagónica de cepas de B. thuringiensis sobre hongos fitopatógenos de importancia agrícola, 2) La inocuidad de las cepas de B. thuringiensis seleccionadas por presentar efecto antagónico hacia alguno de los hongos fitopatógenos sobre plántulas de frijol, chile y tomate, 3) La actividad antagónica de las cepas de B. thuringiensis seleccionadas en el sobrenadante y en el complejo espora cristal, 4) El potencial antagónico de las cepas de B. thuringiensis seleccionadas utilizando una película a base de grenetina-almidón- cepa antagónica sobre semillas de frijol, tomate y/o chile. Los resultados mostraron que el efecto antagónico de B. thuringiensis depende de la cepa utilizada y el hongo fitopatógeno blanco. P. infestans fue el fitopatógeno mas suceptible y la cepa con mayor porcentaje de inhibición para este hongo fue la HD-263. Este trabajo demuestra que algunas cepas de B. thuringienisis pueden ser agentes efectivos de control biológico contra hongos fitopatógeno

Comparing the assimilation of dietary nitrogen supplied by animal-, plant- and microbial-derived ingredients in Pacific white shrimp Litopenaeus vannamei: A stable isotope study

In order to become a more profitable and sustainable industry, the aquaculture sector is constantly exploring alternative nutrient sources. In the present study, the natural stable isotope signatures of different animal-, plantand microbial-derived ingredients were determined to evaluate the assimilation of dietary nitrogen in Pacific white shrimp. Experimental diets were manufactured to replace fish meal and squid meal with microbial- and plant- derived ingredients (48 and 66 % dietary inclusion) and were also used as additives (4%). Ingredients were also used as additives to study their effects on growth performance and assimilation. Corn gluten, soy protein isolate, Arthrospira (Spirulina) biomass and a bacterial meal (ProFloc™) were used to formulate six, isotopic control diets containing one source of dietary nitrogen, while six combined diets had varying proportions of ingredients. At the end of the trial, survival rates were similar among treatments (88 ± 9%) but there were significant differences in mean final weight. Microbial and animal proteins promoted similar final weight when combined (1080−1537 mg), while plant ingredients and Arthrospira caused lower growth when used alone (420−970 mg). Isotopic values indicated significant differences in the assimilation proportions of dietary nitrogen, mainly attributed to the ingredients’ different amino acid profiles. The dietary nitrogen contained in microbial-derived ingredients was assimilated at similar, or even higher proportions than fish meal and squid meal. Diet formulated with 33 % fish meal, Arthrospira and corn gluten, contributed 31, 36 and 33 % of dietary nitrogen to muscle growth, respectively. The second 33 % combination supplied 42, 34 and 24 % from squid meal, bacterial meal and soy protein. When ingredients were used at 4%, additive levels, they also contributed structural nitrogen to shrimp muscle tissue despite low dietary inclusions. Results demonstrated the viable use of stable isotopes to evaluate the assimilation of dietary nitrogen supplied by emerging alternative ingredient

A new geopolymeric binder from hydrated-carbonated cement

This paper evaluates the use of hydrated Portland cement as the raw material in the production of geopolymers. The silicon and aluminium oxides needed for the geopolymerization process were produced by the carbonation of hydrated Portland cement, which transforms CSH and CAH (Portland cement hydrates) into silica and alumina gels. Hydrated-carbonated Portland cement was alkali activated with a NaOH/waterglass solution. Pastes and mortars were prepared, and micro-structural and mechanical properties were analyzed. It has been noted that geopolymers are mechanically stable and yield compressive strength higher than 10 MPa when mortars are cured at 65 °C for 3 days. The results have shown that there are interesting possibilities for re-using the cement-rich fraction of construction and demolition waste. Alkaline activation of hydrated-carbonated Portland cement could be considered a low CO 2-emission binder. © 2012 Elsevier B.V. All rights reserved.Paya Bernabeu, JJ.; Borrachero Rosado, MV.; Monzó Balbuena, JM.; Soriano Martinez, L.; Mitsuuchi Tashima, M. (2012). A new geopolymeric binder from hydrated-carbonated cement. Materials Letters. 74:223-225. doi:10.1016/j.matlet.2012.01.132S2232257

Modeling the compressive strength of geopolymeric binders by gene expression programming-GEP

GEP has been employed in this work to model the compressive strength of different types of geopolymers through six different schemes. The differences between the models were in their linking functions, number of genes, chromosomes and head sizes. The curing time, Ca(OH)2 content, the amount of superplasticizer, NaOH concentration, mold type, aluminosilicate source and H2O/Na2O molar ratio were the seven input parameters considered in the construction of the models to evaluate the compressive strength of geopolymers. A total number of 399 input-target pairs were collected from the literature, randomly divided into 299 and 100 sets and were trained and tested, respectively. The best performance model had 6 genes, 14 head size, 40 chromosomes and multiplication as linking function. This was shown by the absolute fraction of variance, the absolute percentage error and the root mean square error. These were of 0.9556, 2.4601 and 3.4716 for training phase, respectively and 0.9483, 2.8456 and 3.7959 for testing phase, respectively. However, another model with 7 genes, 12 head size, 30 chromosomes and addition as linking function showed suitable results with the absolute fraction of variance, the absolute percentage error and the root mean square of 0.9547, 2.5665 and 3.4360 for training phase, respectively and 0.9466, 2.8020 and 3.8047 for testing phase, respectively. These models showed that gene expression programming has a strong potential for predicting the compressive strength of different types of geopolymers in the considered range

Behavior of metakaolin-based geopolymers incorporating sewage sludge ash (SSA)

[EN] In recent years, geopolymers have become a widely researched binding material. There are technological and environmental advantages tousing this type of binder instead of Portland cement. In this study, binary systems of geopolymers were produced by using mixtures of metakaolin (MK) ,a well-known aluminosilicate raw material, and a residue from sewage sludge incineration: sewage sludge ash (SSA). This ash was used to partially replace the metakaolin in proportions of 0 20%. The mixtures were activated with alkaline solutions and they were cured by using two different conditions: at room temperature (25 °C) and in a thermal bath (65 °C). The samples were assessed by X-ray diffraction, scanning electron microscopy (pastes) and compressive strength (mortars). The results from these studies showed zeolite formation (faujasite) in geopolymers cured in the thermal bath, which caused a decrease in the compressive strength of the alkali-activated mortars.Replacement of MK with SSA caused a lower reduction in the compressive strength of mortars cured at 65 °C. However, at room temperature, similar mechanical strength was observed for the MK and MK-SSA systems. These results demonstrated that SSA is a suitable mineral precursor for partial replacement of MK in geopolymer production.The authors acknowledge Santander Universidades for the grant to Lucia Reig (program: Becas lberoamerica Jovenes Profesores Investigadores Espana 2014), CAPES (CAPES/DGU no 266/12), CNPq (no. 14/2013 processo 478057/2013-0) Scanning electron microscopy service of FEIS/UNESP and CNPq (processo 309015/2015-4).Istuque, D.; Reig Cerdá, L.; Moraes, J.; Akasaki, JL.; Borrachero Rosado, MV.; Soriano Martínez, L.; Paya Bernabeu, JJ.... (2016). Behavior of metakaolin-based geopolymers incorporating sewage sludge ash (SSA). Materials Letters. 180:192-195. https://doi.org/10.1016/j.matlet.2016.05.137S19219518

New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC)

This paper provides information about the synthesis and mechanical properties of geopolymers based on fluid catalytic cracking catalyst residue (FCC). FCC was alkali activated with solutions containing different SiO 2/Na 2O ratios. The microstructure and mechanical properties were analysed by using several instrumental techniques. FCC geopolymers are mechanically stable, yielding compressive strength about 68 MPa when mortars are cured at 65°C during 3 days. The results confirm the viability of producing geopolymers based on FCC. © 2012 Elsevier B.V. All rights reserved.We acknowledge the Ministerio de Ciencia e Innovacion (MICINN) of the Spanish Government and FEDER funds (MAT-2011-19934 project) and the PROPG-UNESP "Universidade Estadual Paulista Julio de Mesquita Filho", Brazil.Mitsuuchi Tashima, M.; Akasaki, JL.; Castaldelli, V.; Soriano Martínez, L.; Monzó Balbuena, JM.; Paya Bernabeu, JJ.; Borrachero Rosado, MV. (2012). New geopolymeric binder based on fluid catalytic cracking catalyst residue (FCC). Materials Letters. 80:50-52. https://doi.org/10.1016/j.matlet.2012.04.051S50528

Long-term survival in patients with non-small cell lung cancer and synchronous brain metastasis treated with whole-brain radiotherapy and thoracic chemoradiation

<p>Abstract</p> <p>Background</p> <p>Brain metastases occur in 30-50% of Non-small cell lung cancer (NSCLC) patients and confer a worse prognosis and quality of life. These patients are usually treated with Whole-brain radiotherapy (WBRT) followed by systemic therapy. Few studies have evaluated the role of chemoradiotherapy to the primary tumor after WBRT as definitive treatment in the management of these patients.</p> <p>Methods</p> <p>We reviewed the outcome of 30 patients with primary NSCLC and brain metastasis at diagnosis without evidence of other metastatic sites. Patients were treated with WBRT and after induction chemotherapy with paclitaxel and cisplatin for two cycles. In the absence of progression, concurrent chemoradiotherapy for the primary tumor with weekly paclitaxel and carboplatin was indicated, with a total effective dose of 60 Gy. If disease progression was ruled out, four chemotherapy cycles followed.</p> <p>Results</p> <p>Median Progression-free survival (PFS) and Overall survival (OS) were 8.43 ± 1.5 and 31.8 ± 15.8 months, respectively. PFS was 39.5% at 1 year and 24.7% at 2 years. The 1- and 2-year OS rates were 71.1 and 60.2%, respectively. Three-year OS was significantly superior for patients with N0-N1 stage disease vs. N2-N3 (60 vs. 24%, respectively; Response rate [RR], 0.03; <it>p</it>= 0.038).</p> <p>Conclusions</p> <p>Patients with NSCLC and brain metastasis might benefit from treatment with WBRT and concurrent thoracic chemoradiotherapy. The subgroup of N0-N1 patients appears to achieve the greatest benefit. The result of this study warrants a prospective trial to confirm the benefit of this treatment.</p

Current Status of Forecasting Toxic Harmful Algae for the North-East Atlantic Shellfish Aquaculture Industry

Across the European Atlantic Arc (Scotland, Ireland, England, France, Spain, and Portugal) the shellfish aquaculture industry is dominated by the production of mussels, followed by oysters and clams. A range of spatially and temporally variable harmful algal bloom species (HABs) impact the industry through their production of biotoxins that accumulate and concentrate in shellfish flesh, which negatively impact the health of consumers through consumption. Regulatory monitoring of harmful cells in the water column and toxin concentrations within shellfish flesh are currently the main means of warning of elevated toxin events in bivalves, with harvesting being suspended when toxicity is elevated above EU regulatory limits. However, while such an approach is generally successful in safeguarding human health, it does not provide the early warning that is needed to support business planning and harvesting by the aquaculture industry. To address this issue, a proliferation of web portals have been developed to make monitoring data widely accessible. These systems are now transitioning from “nowcasts” to operational Early Warning Systems (EWS) to better mitigate against HAB-generated harmful effects. To achieve this, EWS are incorporating a range of environmental data parameters and developing varied forecasting approaches. For example, EWS are increasingly utilizing satellite data and the results of oceanographic modeling to identify and predict the behavior of HABs. Modeling demonstrates that some HABs can be advected significant distances before impacting aquaculture sites. Traffic light indices are being developed to provide users with an easily interpreted assessment of HAB and biotoxin risk, and expert interpretation of these multiple data streams is being used to assess risk into the future. Proof-of-concept EWS are being developed to combine model information with in situ data, in some cases using machine learning-based approaches. This article: (1) reviews HAB and biotoxin issues relevant to shellfish aquaculture in the European Atlantic Arc (Scotland, Ireland, England, France, Spain, and Portugal; (2) evaluates the current status of HAB events and EWS in the region; and (3) evaluates the potential of further improving these EWS though multi-disciplinary approaches combining heterogeneous sources of information.Versión del edito