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ObjectiveRandomised trials of type I anti-CD20 antibodies rituximab and ocrelizumab failed to show benefit in proliferative lupus nephritis (LN). We compared obinutuzumab, a humanised type II anti-CD20 monoclonal antibody that induces potent B-cell depletion, with placebo for the treatment of LN in combination with standard therapies.MethodsPatients with LN receiving mycophenolate and corticosteroids were randomised to obinutuzumab 1000 mg or placebo on day 1 and weeks 2, 24 and 26, and followed through week 104. The primary endpoint was complete renal response (CRR) at week 52. Exploratory analyses through week 104 were conducted. The prespecified alpha level was 0.2.ResultsA total of 125 patients were randomised and received blinded infusions. Achievement of CRR was greater with obinutuzumab at week 52 (primary endpoint, 22 (35%) vs 14 (23%) with placebo; percentage difference, 12% (95% CI −3.4% to 28%), p=0.115) and at week 104 (26 (41%) vs 14 (23%); percentage difference, 19% (95% CI 2.7% to 35%), p=0.026). Improvements in other renal response measures, serologies, estimated glomerular filtration rate and proteinuria were greater with obinutuzumab. Obinutuzumab was not associated with increases in serious adverse events, serious infections or deaths. Non-serious infusion-related reactions occurred more frequently with obinutuzumab.ConclusionsImproved renal responses through week 104 were observed in patients with LN who received obinutuzumab plus standard therapies compared with standard therapies alone. Obinutuzumab was well tolerated and no new safety signals were identified.Trial registration numberNCT02550652.

Phytoremediation techniques have been proposed as ecological methods to clean up contaminated sites. This study is aimed to evaluate the effect of the Streptomyces sp. Waksman & Henrici and Zea mays L. plant system on the dissipation of Cr(VI) and/or lindane from a co-contaminated soil, being 2 mg kg−1 of lindane and 150 mg kg−1 of chromium used. Lindane dissipation was improved in the presence of plant-microorganism association; however, Cr(VI) removal was higher when plants or the microorganism were separately. In co-contaminated systems, chromium content in plant tissues was lower than metal content in plants grown only with Cr(VI), suggesting that lindane could interfere with metal accumulation in the plant. The high malondialdehyde (MDA) concentration detected in non-inoculated plants grown with chromium could be consequence of high metal concentration in plant tissues. Interestingly, plants inoculated with Streptomyces sp. Z38 growing with Cr(VI) showed decrease in MDA concentration, indicating that the bacterium could activate defense mechanisms in the plant. Also, inoculated plants showed the highest value of superoxide dismutase activity. Lettuce plants used as bioindicators grew better in biologically treated soils compared with lettuce grown on non-treated soil. The results presented in this work provide the basis that will allow the optimization of future trials on a larger scale.

Bioremediation using actinobacterium consortia proved to be a promising alternative for the purification of co-contaminated environments. In this sense, the quadruple consortium composed of Streptomyces sp. M7, MC1, A5, and Amycolatopsis tucumanensis AB0 has been able to remove significant levels of Cr(VI) and lindane from anthropogenically contaminated soils. However, the effectiveness of the bioremediation process could not be evaluated only by analytical monitoring, which is complex mainly due to the characteristics of the matrix, producing non-quantitative analyte recoveries, or interferences in the detection stage and quantification. However, the effectiveness of the bioremediation process cannot be evaluated only through analytical monitoring, which is complex due mainly to the characteristics of the matrix, to the recoveries of non-quantitative analytes or to interferences in the detection and quantification stage. For this reason, it is essential to have tools of ecological relevance to assess the biological impact of pollutants on the environment. In this context, the objective of this work was to establish the appropriate bioassays to evaluate the effectiveness of a bioremediation process of co-contaminated soils. For this, five model species were studied: four plant species (Lactuca sativa, Raphanus sativus, Lycopersicon esculentum, and Zea mays) and one animal species (Eisenia fetida). On plant species, the biomarkers evaluated were inhibition of germination (IG) and the length of hypocotyls/steam and radicles/roots of the seedling. While on E. fetida, mortality (M), weight lost, coelomocyte concentration and cell viability were tested. These bioindicators and the battery of biomarkers quantified in them showed a different level of sensitivity, from maximum to minimum: E. fetida > L. esculentum > L. sativa > R. sativus ≫> Z. mays. Therefore, E. fetida and L. esculentum and their respective biomarkers were selected to evaluate the effectiveness of the bioremediation process due to the capability of assessing the effect on the flora and the fauna of the soil, respectively. The joint application of these bioindicators in a field scale bioremediation process is a feasible tool to demonstrate the recovery of the quality and health of the soil. Fil: Aparicio, Juan Daniel. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Garcia Velasco, Nerea. Universidad del País Vasco; España Fil: Urionabarrenetxea, Erik. Universidad del País Vasco; España Fil: Soto, Manu. Universidad del País Vasco; España Fil: Álvarez, Analía. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Polti, Marta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Old Yellow Enzymes play key roles in several cellular processes and have become an important family of enzymes withbiotechnological potential. One of the major challenges of biotechnology consists of the bioremediation of co-polluted soilswith organic and inorganic compounds. In co-contaminated areas, chromium normally exists in its more toxic and carcinogenicform Cr(VI). Microorganisms can reduce this metal to the insoluble and less toxic Cr(III).Streptomycessp. M7 is a strain able toefficiently bioremediate polluted soils withγ-hexachlorocyclohexane and Cr(VI). The complete degradation pathway for γ-hexachlorocyclohexane was recently elucidated in this strain. In the present work, we confirmed the ability ofStreptomycessp.M7 to eliminate a high percentage of Cr(VI) from a synthetic culture medium. After a transcriptional study in the presence ofCr(VI), we also report the molecular cloning of a gene coding for an Old Yellow Enzyme with chromate reductase activity. Ourresults suggest that the elimination of Cr(VI) byStreptomycessp. M7 is directly related to the activity of this Old Yellow Enzyme.The importance of our work is in identifying for the first time an Old Yellow Enzyme with chromate reductase activity inStreptomycesand Actinobacteria. Finding this enzyme helps understand chromium homeostasis inStreptomycessp. M7, inaddition to opening a new research window related to Old Yellow Enzymes from Actinobacteria. Fil: Sineli, Pedro Eugenio. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Guerrero, Daiana. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Dávila Costa, José Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Environmental contamination is a problem that currently faces the world-wide population due to extensive industrialization, urbanization, and new agricultural practices. Several and different pollutants profoundly alter water, soil, and air, producing biodiversity extinction, the decline in soil condition, and harming human health. Hence, various environmental remediation systems have been investigated, using biological and physicochemical approaches. This chapter examines new techniques for the remediation of contaminated systems using nanotechnology. General concepts about nanoparticles such as, types, methods of production, properties, and distinctive characteristics. It focuses in particular on the use of green synthesis nanoparticles for the bioremediation of soils and water.

The diversity of cultivable bacteria associated with plants from phytomanaged soils with mixed trace metal (TM) and polycyclic aromatic hydrocarbon (PAH) contamination in Pierrelaye (France) was evaluated. The emphasis was on the cultivable bacterial community since the overall objective is to obtain inoculants to improve the remediation of this type of contaminated site. Root endophytic and rhizosphere soil bacterial counts were determined, and isolates were pooled by amplified rDNA restriction analysis and identified by 16S rDNA sequencing. Isolates were further characterized for the production of plant growth-promoting (PGP) substances, and resistance to TM. The selected strains were evaluated for their ability to degrade PAHs. The potential of cell-free microbial supernatant to increase the mobilisation of PAHs from the polluted soil of Pierrelaye was also evaluated. Proteobacteria and Actinobacteria dominated the collection of isolates, and differences in taxonomic diversity were observed between plant species (Populus or Zea mays) and depending on the remediation treatment (Populus inoculation with mycorrhizae or Populus intercropping with Alnus). The majority of isolates exhibited at least one of the tested PGP traits, as well as resistance to more than one TM. Several rhizosphere, endophyte and even one bulk soil isolate showed high rates of fluoranthene and pyrene reduction. The endophyte Rhizobium strain MR28 isolated from maize and degrading pyrene produced bioemulsifying molecules capable of improving the availability of PAHs from the soil of Pierrelaye. A selection of the most interesting strains was made for further re-inoculation experiments in order to assess their potential in rhizoremediation processes., This work was supported by the Agence Nationale de la Recherche (ANR) under the PRECODD (ANR-06-ECOT-O15-01- PHYTOPOP) and the Blanc International (ANR-10-INTB-1703-01- BIOFILTREE) projects.

Phytoremediation techniques have been proposed as ecological methods to clean up contaminated sites. This study is aimed to evaluate the effect of the Streptomyces sp. WaksmanHenrici and Zea mays L. plant system on the dissipation of Cr(VI) and/or lindane from a co-contaminated soil, being 2 mg kg

The genus Streptomyces is widely recognized for its biotechnological potential. Due to a need to improve crops,clean up the environment and produce novel antimicrobial molecules exploiting Streptomyces has become apriority. To further explore the biotechnological potential of these organisms we analyzed the genome of thestrain Streptomyces sp. Z38 isolated from contaminated roots tissues. Our analysis not only confirmed the abilityof the strain to produce plant growth promoting traits but also a range of mechanisms to cope with the toxiceffect of heavy metals through genes involved in metal homeostasis and oxidative stress response. The production of silver nanoparticles indicated that Streptomyces sp. Z38 may find utility in Green, Grey and Redbiotechnology Fil: Dávila Costa, José Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Hoskisson, Paul Alan. University of Strathclyde; Reino Unido Fil: Paterlini, Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Romero, Cintia Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Background Previous analyses identified associations between the degree of B-cell depletion and response in lupus nephritis (LN). NOBILITY tested whether enhanced B-cell depletion with the type II anti-CD20 mAb obinutuzumab could improve responses in LN. Methods 126 patients with active Class III/IV LN were randomized to obinutuzumab or placebo infusions in combination with mycophenolate and corticosteroids. Peripheral B-cells were measured using a flow cytometry method with a lower limit of 0.441 cells/μL. Sustained depletion was assessed by flow cytometry measurements at weeks 24 and 52. Results Obinutuzumab was associated with increased CRR (40% vs. 18%, P=0.007) and ORR (51% vs. 29%, P =0.015) at week 76. Obinutuzumab resulted in rapid and complete depletion of peripheral B-cells, memory and naive B-cell subsets, and plasmablasts, with 89% of obinutuzumab patients depleted to Conclusions Obinutuzumab, a type II anti-CD20 mAb, induced rapid and complete depletion of peripheral B-cells and B-cell subsets. Similar to previous reports, sustained B-cell depletion was associated with increased renal response. Further evaluation is ongoing to understand the factors associated with achievement of sustained B-cell depletion and renal response. Acknowledgements This study was funded by F. Hoffmann-La Roche.

The resistance of common or resurgent pathogens to standard antibiotic therapies is a significant health problem, so the need for new antimicrobial sources is imperative. It is widely known that the most promising source of new drugs remains natural products, mainly those of microbial origin. Such is the case of microbial nanoparticles (NPs) which have unusual physical, chemical, and biological properties like as powerful antibacterial activities. While NPs synthesized by chemical methods involve hazardous and expensive processes, nano-biosynthesis is a green technology by which NPs are obtained through biological processes such as the reduction of a metal salt by the action of biomolecules.

Actinobacteria exhibit cosmopolitan distribution since their members are widely distributed in aquatic and terrestrial ecosystems. In the environment they play relevant ecological roles including recycling of substances, degradation of complex polymers, and production of bioactive molecules. Biotechnological potential of actinobacteria in the environment was demonstrated by their ability to remove organic and inorganic pollutants. This ability is the reason why actinobacteria have received special attention as candidates for bioremediation, which has gained importance because of the widespread release of contaminants into the environment. Among organic contaminants, pesticides are widely used for pest control, although the negative impact of these chemicals in the environmental balance is increasingly becoming apparent. Similarly, the extensive application of heavy metals in industrial processes lead to highly contaminated areas worldwide. Several studies focused in the use of actinobacteria for cleaning up the environment were performed in the last 15 years. Strategies such as bioaugmentation, biostimulation, cell immobilization, production of biosurfactants, design of defined mixed cultures and the use of plant-microbe systems were developed to enhance the capabilities of actinobacteria in bioremediation. In this review, we compiled and discussed works focused in the study of different bioremediation strategies using actinobacteria and how they contributed to the improvement of the already existing strategies. In addition, we discuss the importance of omic studies to elucidate mechanisms and regulations that bacteria use to cope with pollutant toxicity, since they are still little known in actinobacteria. A brief account of sources and harmful effects of pesticides and heavy metals is also given. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Dávila Costa, José Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Colin, Veronica Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Cuozzo, Sergio Antonio. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Polti, Marta Alejandra. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Restoring polluted sites by petroleum hydrocarbons is a challenge because of their complexity and persistence in the environment. The main objective of the present study was to investigate the performance of plant-actinobacteria system for the remediation of crude petroleum and pure-polycyclic aromatic hydrocarbons (PAHs) contaminated soils. The endophytic strain Streptomyces sp. Hlh1 was tested for its ability to degrade model PAHs (phenanthrene, pyrene and anthracene) in liquid minimal medium. Streptomyces sp. Hlh1 demonstrated the ability to grow on PAHs as sole carbon and energy source, reaching hydrocarbons removal of 63%, 93% and 83% for phenanthrene, pyrene and anthracene, respectively. Maize plant was chosen to study the impact of Streptomyces sp. Hlh1 inoculation on the dissipation of contaminants and plant growth. Thus, maize seedlings grown in soils contaminated with crude petroleum and pure-PAHs were inoculated with Streptomyces sp. Hlh1. Results showed that the endophyte inoculation increased contaminants removal. Maximum hydrocarbons removal (70%) was achieved in inoculated and planted soil contaminated with crude oil, while 61%, 59%, and 46% of hydrocarbons dissipation were registered for phenanthrene, pyrene and anthracene, respectively. These degradations rates were significantly higher compared to non-inoculated systems in all the treatments evaluated. Further, it was revealed that hydrocarbons (C8–C30) were efficiently degraded in plant-Streptomyces Hlh1 system. Moreover, the inoculation with the actinobacteria resulted significant plant development and enhanced photosynthetic pigments compared to plants grown in the other experimental conditions. The present study provide evidence that the inoculation of maize plants with Streptomyces sp. Hlh1 play a remarkable role in the removal of petroleum hydrocarbons, enhancing plant development in contaminated soils. Fil: Baoune, Hafida. Laboratoire de Protection Des Écosystème En Zones Aride; Argelia Fil: Aparicio, Juan Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Acuña, Adrian Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Tecnológica Nacional. Facultad Regional Santa Cruz. Centro de Investigaciones y Transferencia de Santa Cruz. Universidad Nacional de la Patagonia Austral. Centro de Investigaciones y Transferencia de Santa Cruz; Argentina Fil: El Hadj-khelil, Aminata Ould. Laboratoire de Protection Des Écosystème En Zones Aride; Argelia Fil: Sanchez, Leandro Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Polti, Marta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Alvarez, Analia. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

The aim of the present study was to investigate care and risk practices carried out in nightlife settings with massive presence of people in the Autonomous City of Buenos Aires. In addition to this, the perceived reasons behind the consumption of psychoactive substances were investigated. For this purpose, 16 young people between 21 and 35 years of age were interviewed. The data was analyzed following the approach proposed in the grounded theory and using the Atlas.Ti program. Practices were studied at individual, group and environmental levels. Among the risk practices, substance availability, excessive intake and substance mixing were frequently mentioned. Regarding care practices, the value of the group was highlighted by keeping together and providing help to its members. Practical implications of these results are discussed, and limitations and future lines of research are presented.El objetivo del presente estudio fue indagar las prácticas de cuidado y de riesgo que se despliegan en escenarios nocturnos de presencia masiva de la Ciudad Autónoma de Buenos Aires. Asimismo, se indagaron los motivos percibidos para el consumo de sustancias psicoactivas. Para ello se entrevistó a 16 jóvenes de entre 21 a 35 años de edad. Los datos fueron analizados siguiendo la propuesta de la teoría fundamentada y con el soporte del programa Atlas.Ti. Se analizaron prácticas individuales, prácticas grupales, y a nivel del entorno. Entre las prácticas de riesgo se mencionaron con frecuencia la disponibilidad de las sustancias, la ingesta excesiva y las mezclas. Respecto de las prácticas de cuidado, se destacó el valor del grupo al mantenerse todos juntos y brindar ayuda a sus miembros. Se discuten las implicancias prácticas de estos resultados, y se presentan las limitaciones y líneas futuras de investigación.

The present work reports the production of bioemulsifiers (BEs) by an environmental bacterium closely related to Bacillus spp., using agro-industrial wastes and by-products as low-cost carbon sources. Maximum emulsifying activity was detected using crude glycerol (CG) (E 24 = 59%), producing 2.8 g/L of BE at 24 h of incubation. The microbial product presented significantly higher biodegradability in comparison to three commercial emulsifying agents (sodium dodecyl sulfate, SDS; Tween 80; and Arabic gum, AG). Interestingly, BE proved to be innocuous for Caco-2 cells and wheat seedlings, used as toxicological indicators. The BE and AG showed (in most of the cases) higher stability to changes in temperature (37 °C–100 °C), pH (3–10), and salt concentration (5% and 10%, w/v) in comparison to the SDS and Tween 80. Finally, the microbial product displayed a large affinity to a wide range of hydrophobic substrates showing emulsifying activities similar to or even better than SDS, Tween 80 and AG. The results presented in this study demonstrate the potential of a bioproduct obtained from CG to be used for environmental purposes. Fil: Rulli, Macarena María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Colin, Veronica Leticia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

RESUMEN El objetivo del presente estudio fue indagar las prácticas de cuidado y de riesgo que se despliegan en escenarios nocturnos de presencia masiva de la Ciudad Autónoma de Buenos Aires. Asimismo, se indagaron los motivos percibidos para el consumo de sustancias psicoactivas. Para ello se entrevistó a 16 jóvenes de entre 21 a 35 años de edad. Los datos fueron analizados siguiendo la propuesta de la teoría fundamentada y con el soporte del programa Atlas.Ti. Se analizaron prácticas individuales, prácticas grupales, y a nivel del entorno. Entre las prácticas de riesgo se mencionaron con frecuencia la disponibilidad de las sustancias, la ingesta excesiva y las mezclas. Respecto de las prácticas de cuidado, se destacó el valor del grupo al mantenerse todos juntos y brindar ayuda a sus miembros. Se discuten las implicancias prácticas de estos resultados, y se presentan las limitaciones y líneas futuras de investigación. ABSTRACT The aim of the present study was to investigate care and risk practices carried out in nightlife settings with massive presence of people in the Autonomous City of Buenos Aires. In addition to this, the perceived reasons behind the consumption of psychoactive substances were investigated. For this purpose, 16 young people between 21 and 35 years of age were interviewed. The data was analyzed following the approach proposed in the grounded theory and using the Atlas.Ti program. Practices were studied at individual, group and environmental levels. Among the risk practices, substance availability, excessive intake and substance mixing were frequently mentioned. Regarding care practices, the value of the group was highlighted by keeping together and providing help to its members. Practical implications of these results are discussed, and limitations and future lines of research are presented.

Microbial mineralization offers an efficient alternative to obtain metallic nanoparticles. The aim of this work was to synthesize green silver nanoparticles (AgNPs) using the metal resistant strain Streptomyces sp. M7. In addition, molecular modeling and docking studies were performed in order to understand how stabilizing proteins interact with the nanoparticle’s surface. The production of AgNPs was influenced by the incubation time. AgNPs showed a moderate polydispersity of size and spherical shape. The hydrodynamic diameter was determined by Dynamic Light Scattering (DLS). Fourier Transform Infrared Spectroscopy (FTIR) and Raman analysis showed that organic molecules such as oxide-reduction enzymes coated the AgNPs surface. Molecular modeling and docking studies indicated that actually different enzymes may be simultaneously bound to the nanoparticle surface forming a layer capping-protein with different affinities. Thermogravimetric analysis (TGA) showed high thermal resistance of AgNPs, probably by the presence of organic residues on the surface. The green synthesized AgNPs showed antimicrobial activity against several multidrug-resistant bacteria, particularly Serratia marcescens SmCR371. This strain belongs to a cluster with epidemic behavior, harboring an extended spectrum of β -lactamases and carbapenemase. AgNPs produced by Streptomyces sp. M7 could be considered as a new line of defense against microbial resistance or as a complement of traditional antibiotics.

The aims of this study were (1) to isolate new multi-resistant actinobacteria from soil, rhizosphere and plant samples collected from an ancient illegal pesticide storage and (2) to elucidate the effects of these microorganisms developed with maize root exudates on lindane and Cr(VI) removal. Fifty-seven phenotypically different actinobacteria were isolated and four of them, belonging to the genus Streptomyces exhibit tolerance to a mixture of lindane and Cr(VI). Two rhizospheric strains named as Streptomyces sp. Z38 and Streptomyces sp. Z2 were selected to be grown with root exudates because they showed the highest Cr(VI) and lindane removal in co-contaminated medium. When root exudates were the only carbon source, metal dissipation increased significantly either as single or mixed contaminant, compared to metal dissipation with glucose. No significant differences were found on lindane removal with root exudates or glucose, so a higher lindane concentration was evaluated. Despite of this, lindane removal remained stable while metal dissipation was notoriously lower when lindane concentration was enhanced. In addition to a good performance growing with mixed contaminants, Streptomyces strains showed plant growth promoting traits that could improve plant establishment. The results presented in this study show the importance of the screening programs addressed to find new actinobacteria able to grow in co-contaminated systems. It was also evidenced that root exudates of maize improve the growth of Streptomyces strains when they were used as carbon source, being the dissipation of Cr(VI) considerably improved in presence of lower lindane concentration. Fil: Simón Solá, María Zoleica. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Lovaisa, Nadia Carolina. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto Superior de Investigaciones Biológicas. Universidad Nacional de Tucumán. Instituto Superior de Investigaciones Biológicas; Argentina Fil: Dávila Costa, José Sebastián. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Benimeli, Claudia Susana. Universidad Nacional de Catamarca; Argentina Fil: Polti, Marta Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Alvarez, Analia. Universidad Nacional de Tucumán; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Nanotechnology is a wide developing area of the biotechnology since the important applications of nanoparticles (NPs) in different technologies. The NPs produced by green technologies have many advantages such as greater surface area, high catalytic activity, in addition to providing a suitable contact between the metal salt and enzyme. Fungi secrete proteins, enzymes and reducing agents which can be used for the synthesis of metal NPs from metal salts. The biosynthesis of metal NPs by fungi has been explored in recent years, evaluating the extracellular and intracellular chemistry of formation. Emphasis has been given to the potential of metal NPs as an antimicrobial agent to inhibit the growth of pathogenic bacteria and fungi and other potential applications such as their cytotoxic activity against cancer cell lines. Further, the metal NPs are being explored as promising candidates for several biomedical, pharmaceutical, and agricultural applications. Fil: Romero, Cintia Mariana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Martinez, Maria Alejandra. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Chavez Clemente, Mónica Silvina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina

The impact of plant species invasions onthe abundance, composition and activity of fungaldecomposers of leaf litter is poorly understood. In thisstudy, we isolated and compared the relative abundanceof ligninocellulolytic fungi of leaf litter mixturesfrom a native forest and a forest invaded byLigustrum lucidum in a lower mountain forest ofTucuman, Argentina. In addition, we evaluated therelationship between the relative abundance ofligninocellulolytic fungi and properties of the soil ofboth forest types. Finally, we identified lignin degradingfungi and characterized their polyphenol oxidaseactivities. The relative abundance of ligninocellulolyticfungi was higher in leaf litter mixtures from thenative forest. The abundance of cellulolytic fungi wasnegatively related with soil pH while the abundance ofligninolytic fungi was positively related with soilhumidity. We identified fifteen genera of ligninolyticfungi; four strains were isolated from both forest types,six strains only from the invaded forest and five strainswere isolated only from the native forest. The resultsfound in this study suggest that L. Lucidum invasioncould alter the abundance and composition of fungaldecomposers. Long-term studies that include ananalysis of the nutritional quality of litter are needed,for a more complete overview of the influence ofL. Lucidum invasion on fungal decomposers and onleaf litter decomposition. Fil: Fernandez, Romina Daiana. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional.; Argentina Fil: Bulacio Gil, Natalia María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Pajot, Hipolito Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Aragón, Myriam Roxana. Universidad Nacional de Tucumán. Instituto de Ecología Regional. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Instituto de Ecología Regional.; Argentina

Lindane is a cyclic, saturated and highly chlorinated pesticide with a broad spectrum, which has been used worldwide for many decades to control a variety of pests, and also in human health and veterinary. Afterward, it has been demonstrated that lindane and its isomers may cause serious damage to health in the short and long term. Besides, lindane is known to be persistent in the environment and tends to bioaccumulate along the food chain. Thus, lindane residues remain in the environment for a long time and have been recently found in water, soil, sediments, plants, and animals all over the world, and even in human fluids and tissues. In this context, nowadays, scientists, working all over the world, are involved in developing lindane remediation technologies including physical, chemical, and biological techniques. This article provides updated information on the biologic degradation of lindane using different microorganisms such as bacteria, fungi, and algae, under both aerobic and anaerobic conditions.

In the last few decades, highly toxic organic compounds like the organochlorine pesticide (OP) hexachlorocyclohexane (HCH) have been released into the environment. All HCH isomers are acutely toxic to mammals. Although nowadays its use is restricted or completely banned in most countries, it continues posing serious environmental and health concerns. Since HCH toxicity is well known, it is imperative to develop methods to remove it from the environment. Bioremediation technologies, which use microorganisms and/or plants to degrade toxic contaminants, have become the focus of interest. Microorganisms play a significant role in the transformation and degradation of xenobiotic compounds. Many Gram-negative bacteria have been reported to have metabolic abilities to attack HCH. For instance, several Sphingomonas strains have been reported to degrade the pesticide. On the other hand, among Gram-positive microorganisms, actinobacteria have a great potential for biodegradation of organic and inorganic toxic compounds. This review compiles and updates the information available on bacterial removal of HCH, particularly by Streptomyces strains, a prolific genus of actinobacteria. A brief account on the persistence and deleterious effects of these pollutant chemical is also given.

The organochlorine pesticide (OP) lindane was removed from minimal medium (MM) by two Streptomyces native strains, while growing on maize root exudates (REs) as a primary carbon and energy source. REs supported 55 and 35% of lindane removal by Streptomyces sp. strains A5 and M7, respectively, corroborating the hypothesis that co-metabolism may be a plant/microbe interaction important to bioremediation. In addition, residual lindane concentration was more than half of the amount in MM supplemented with glucose compared to MM supplemented with REs, suggesting that exudates could be more appropriate carbon source to support aerobic dehalogenation of the pesticide. Lindane-degrading activity was detected in REs, which could explain 42% of lindane removal in REs-lindane assay, without microorganisms. Because Streptomyces sp. A5 showed maximum biomass and the highest pesticide removal in REs-lindane assay, it was found to be the most promising strain regarding their future application. These results showed that phytostimulation of OP-degrading actinobacteria by maize REs are therefore likely to be a successful strategy for the remediation of lindane-contaminated environments. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Yañez, M. L.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina Fil: Amoroso, Maria Julia del R.. Universidad del Norte Santo Tomás de Aquino. Facultad de Ciencias de la Salud; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina

The aim of this research was to identify the existence of different Spodoptera frugiperda (J.E. Smith) (FAW) host strains in Argentina, and to determine their behaviors in the presence of different mortality factors. Populations belonging to these strains were tested with the pesticides chlorpyriphos and cypermethrin, transgenic corn germplasms expressing Cry proteins 1Ab or 1F, and an indigenous Bacillus thuringiensis strain. The relation of these strains with the host plant species and crop utilization, subsistence or commercial ones, is discussed. The response to the assayed insecticides, Bt transgenic corn and Bt suspension was diverse, showing wide variability in mortality rates. This research validates the need of intensive studies relating resistance phenomena with the differential behavior of the host strains inhabiting Argentina. Host plant and crop utility is not a determinant for the identity of the colonizing strain, so molecular identification of the strains is highly recommended bef...

Background and aims: Plants and contaminant-degrading microbes are a suitable combination for the remediation of pesticides. The aim of this study was to evaluate the effectiveness of Streptomyces strains cultured with maize plants in relation to lindane removal.Methods: Four Streptomyces strains were cultured and added as both single and mixed cultures, along with maize plants, to artificially polluted hydroponic systems and soils. The effectiveness of the resulting soil bioremediation was then evaluated through phytotoxicity testing using lettuce seedlings.Results: In the hydroponic and soil experiments, similar levels of lindane removal were recorded in the inoculated and non-inoculated systems where maize plants were introduced. However, the vigor index (VI) of the maize plants was highest when grown in inoculated and artificially polluted soil. In the phytotoxicity assay, the VI of the lettuce seedlings increased with increasing bioremediation time for the soils, thus indicating the effectiveness of the process.Conclusions: Similar levels of lindane removal were recorded in both inoculated and non-inoculated planted systems, indicating that pesticide removal was not significantly affected by the bacterial inoculant. However, inoculation an actinobacteria consortium led to an increase in the VI of the maize and protected the plants against the existing toxicity. Furthermore, maize plants may attenuate the transient toxic effects of microbial lindane degradation. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina Fil: Giuliano, Agostina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina

Lindane is a chlorinated insecticide which was used worldwide. Nowadays its persistence, bioaccumulation and toxicity are well known. One of the strategies for its elimination is bioremediation. For this purpose, the use of slurry reactors for contaminated soils is considered an efficient technology. Moreover, using immobilized cells in this process could provide protection for microorganisms against the contaminants and also allows reuse. The aim of this study was to assess lindane removal from soil slurry by a Streptomyces consortium immobilized in cloth sachets, at different inoculum, lindane and slurry concentrations. In concentrated slurry, the higher lindane removal (35.3 mg Kg-1) was obtained with the medium inoculum (107 CFU g-1) and the higher lindane concentration tested, at 7 days of incubation. Although, lindane removal was also detected in abiotic controls, probably due to a physical phenomenon of adsorption of the pesticide to soil particles. Thus, these parameters were selected for evaluating the pesticide removal in a more diluted slurry. After 14 days of incubation, 28.7 mg Kg-1 of lindane was removed. Besides, phytotoxicity assay demonstrated that seeds grown on diluted slurries bioremediated during 7 and 14 days showed an improvement in biological paramethers, respect to non-bioremediated slurry. Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Benimeli, Claudia Susana. Universidad del Norte Santo Tomás de Aquino; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman; Argentina Fil: Amoroso, Maria Julia del R.. Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucuman. Planta Piloto de Procesos Industriales Microbiologicos; Argentina. Universidad del Norte Santo Tomás de Aquino; Argentina

Methoxychlor (MTX) is an organochlorine pesticide which has been banned in most countries; however, it is still being used in agricultural products and against mosquito. This pesticide has estrogenic activity and mimics endocrine hormone functions. Thus, it is important to analyze its behavior in different matrices.

Methoxychlor is an organochlorine pesticide used worldwide against several insect pests, resulting in human exposure. This pesticide mimics endocrine hormone functions, interfering with normal endocrine activity in humans and wildlife. For this reason, it is imperative to develop methods to remove this pesticide from the environment, and though, bioremediation using microorganisms results as an excellent strategy. Five Streptomyces spp. strains previously isolated from organochlorine-polluted sites and capable to grow and remove methoxychlor were combined as different mixed cultures to increase methoxychlor removal. From the 39 consortia tested, one consortium (Streptomyces spp. A6, A12, A14, M7) was selected because of its high pesticide removal and specific dechlorinase activity to be assayed on slurry and soil systems. This consortium showed higher biomass values (8.3 9 106 ± 5.7 9 105 CFU mL-1) and methoxychlor removal (56.2 ± 2.3 %) on enriched slurry than in nonenriched slurry (7.3 9 105 ± 1.2 9 105 CFU mL-1 and 45.6 ± 7.4 % of pesticide removal). In soil systems, Streptomyces consortium showed higher growth (1.0 9 1011 ± 5.0 9 1010 CFU g-1) than in enriched slurry, although differences in methoxychlor removal between both culture conditions were not statistically significant. Therefore, the selected Streptomyces consortium may be suitable for the development of in situ (soil) and ex situ (slurry bioreactor) bioremediation methods because of their potential to remove methoxychlor from different systems. Fil: Fuentes, María Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina; Fil: Sáez, Juliana María. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Fil: Benimeli, Claudia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Unidad de Administración Territorial; Argentina; Universidad del Norte Santo Tomás de Aquino; Argentina; Fil: Amoroso, Maria Julia del R.. Universidad del Norte Santo Tomás de Aquino; Argentina; Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina; Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina

The genus Streptomyces comprises a group of bacteria species with high economic importance. Several of these species are employed at industrial scale for the production of useful compounds. Other characteristic found in different strains within this genus is their capability to tolerate high level of substances toxic for humans, heavy metals among them. Although several studies have been conducted in different species of the genus in order to disentangle the mechanisms associated to heavy metal resistance, little is known about how they have evolved along Streptomyces phylogeny. In this study we built the largest Streptomyces phylogeny generated up to date comprising six genes, 113 species of Streptomyces and 27 outgroups. The parsimony-based phylogenetic analysis indicated that (i) Streptomyces is monophyletic and (ii) it appears as sister clade of a group formed by Kitasatospora and Streptacidiphilus species, both genera also monophyletic. Streptomyces strains resistant to heavy metals are not confined to a single lineage but widespread along Streptomyces phylogeny. Our result in combination with genomic, physiological and biochemical data suggest that the resistance to heavy metals originated several times and by different mechanisms in Streptomyces history. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina; Fil: Catalano, Santiago Andres. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina; Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo. Instituto Superior de Entomología; Argentina; Fil: Amoroso, Maria Julia del R.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico - CONICET - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos (i); Argentina; Universidad Nacional de Tucumán. Facultad de Bioquímica, Química y Farmacia; Argentina; Universidad del Norte Santo Tomás de Aquino; Argentina

Bacillus thuringiensis (Bt) is a spore-forming bacterium well-known for its insecticidal properties associated with its ability to produce crystal inclusions during sporulation. These inclusions are proteins encoded by cry genes and have shown to be toxic to a variety of insects and other organisms like nematodes and protozoa . The primary action of Cry proteins is to lyse midgut epithelial cells through insertion into the target membrane and form pores . Once ingested, crystals are solubilized in the alkaline environment of midgut lumen and activated by host proteases . On the other hand, the involvement of Bt proteases in processing inactive protoxins is also reported. These toxins are also highly specific and completely biodegradable, hence no toxic products are accumulated in the environment. In fact, Calderón et al. suggest the potential use of some crystal proteins as adjuvants for the administration of heterologous antigens.The activity spectrum of Bt toxins continually increases as result of the ongoing isolation of new strains around the world. The fall armyworm, Spodoptera frugiperda (S. frugiperda) (Lepidoptera: Noctuidae), and the variegated cutworm, Peridroma saucia (P. saucia) (Lepidoptera: Noctuidae), are two lepidopteran pests that cause severe damage to a variety of crops. While the first one mainly attacks corn, rice, peanuts, cotton, soybeans, alfalfa and forage grasses, the second one targets peanuts, sunflowers, soybeans and grapevines, among others . Currently, control of this pest relies on chemical insecticides. Nevertheless, the rapid increases in resistance to insecticides together with the potential adverse environmental effects produced by these chemicals have encouraged the development of alternative methods for Lepidoptera control . Among these methods the use of Bt as a biocontrol agent has shown to be extremely valuable. The diversity of Cry toxins produced by Bt allows the formulation of a variety of bioinsecticides by using the bacteria themselves or by expressing their toxin genes in transgenic plants. To date, many plant species have been genetically modified with cry genes, resulting in transgenic plants with a high level of resistance to insect . However, it has been reported that several pests have developed resistance against Cry proteins . The current approach used to delay evolution of resistance to transgenic crops uses a "high dose" and "refuge" strategy . In addition, it is important to use a combination of cry genes and/or other genes encoding insecticidal proteins within the same transgenic crop . Due to extensive use of transgenic crops in developing countries based on cry-type genes, there is a need for alternative cry gene sequences to meet the challenge of novel insect resistance . Crucial to this development is the identification of novel and more active strains with respect to insect pests of economically important crops. The cry genes of Bt strains are known to be related to their toxicity and identification of these genes by means of PCR has been used to characterize and predict insecticidal activity of the strains . Nevertheless, a more complete characterization should include alternative methods. Phenotypical analysis such as protein profile determination provides useful information for typing and comparative studies. The literature data report the possibility of using the whole-cell protein profile as a discriminating method with potency similar to RAPD with combined DNA patterns. However, there is not always a good correlation between these factors and insecticidal activity of Bt strains. In addition, there is a need to develop knowledge about the biological properties and diversity of Bt isolates since these data allow a better understanding of the biological factors that determine insecticidal properties. Extracellular factors such as phospholipases, proteases and chitinases have shown to contribute to insecticidal activity of Bt . During a screening programme of Bt isolates native to Argentina and toxic against Lepidoptera, several strains were characterized according to different biological parameters. In addition, promising isolates regarding their useful in biological control programmes -an environmentally safe technology of pest control- were exhaustively studied . The present work showed most relevant results obtained during a course of those investigations. The discovery of highly pathogenic isolates against devastating insect pests reveals the usefulness of screening studies for novel Bt strains. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Loto, Flavia del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Two Bacillus thuringiensis strains isolated from diseased Spodoptera frugiperda larvae collected in the northwest of Argentina were molecularly and phenotypically characterized. Insecticidal activity against Spodoptera frugiperda larvae was also determined. Both strains were highly toxic against first instar larvae. One strain (Bacillus thuringiensis LSM) was found to be even more toxic than the reference strain Bacillus thuringiensis var. kurstaki 4D1. This strong biological effect was represented by both a higher mortality which reached 90%, and a shorter LT50. Molecular characterization showed that Bacillus thuringiensis LSM carried a cry gene profile identical to that of Bacillus thuringiensis var. kurstaki 4D1. Evaluation of length polymorphism of the intergenic transcribed spacers between the 16S and 23S rDNA genes revealed an identical pattern between native strains and Bacillus thuringiensis var. kurstaki 4D1. In contrast, phenotypic characterization allowed differentiation among the isolates by means of their extracellular esterase profiles. Lytic activity that would contribute to Bacillus thuringiensis effectiveness was also studied in both strains. Analyses like those presented in the current study are essential to identify the most toxic strains and to allow the exploitation of local biodiversity for its application in biological control programmes. © 2011 Springer Science+Business Media B.V. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina. Universidad Nacional de Tucumán. Facultad de Ciencias Naturales e Instituto Miguel Lillo; Argentina Fil: Virla, Eduardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Pera, Licia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Baigori, Mario Domingo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Twelve Bacillus thuringiensis (Bt) strains, isolated from larvae and soil samples in Argentina, were molecularly and phenotypically characterized and their insecticidal activities against Spodoptera frugiperda and Peridroma saucia were determined. One isolate—Bt RT—produced more than 93% mortality on first instar larvae of both species, which was higher than that produced by the reference strain Bt 4D1. Bt RT carried a different cry gene profile than Bt 4D1. Scanning electron microscopy showed the presence of bipyramidal and cuboidal crystals. Phenotypic characterization revealed lytic enzymes that could contribute to Bt pathogenicity. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Virla, Eduardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Pera, Licia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Baigori, Mario Domingo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina

Fourteen strains of Bacillus thuringiensis collected from both larvae showing disease symptoms and soil samples in northwest Argentina were characterized by insecticidal activity against Spodoptera frugiperda. First instar larvae and protein profile SDS-PAGE analysis of whole cell proteins not only allowed the differentiation of native Bacillus thuringiensis but also revealed the possibility of applying protein profile analysis in classification of toxicity patterns. Cluster analysis showed that there were two main groups. Interestingly, one of them only contained the most pathogenic native strains. The biomass-bound protease activity of native pathogenic isolates and the reference strain Bt 4D1 is also reported. Fil: Alvarez, Analia. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Pera, Licia Maria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Loto, Flavia del Valle. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Virla, Eduardo Gabriel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina Fil: Baigori, Mario Domingo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tucumán. Planta Piloto de Procesos Industriales Microbiológicos; Argentina