Changes in the mechanical properties of compression moulded samples of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) degraded by Streptomyces omiyaensis SSM 5670

Streptomyces omiyaensis SSM 5670 was characterized by its ability to use compression moulded samples of poly(3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) as its sole carbon source. Biodegradation of PHBV in liquid mineral salts medium was investigated using scanning electron microscopy, gravimetric measurements, capillary viscometry, tensile testing and wide angle X-ray spectroscopy. The biodegradation of PHBV proceeds via surface erosion mechanism, resulting in the formation of pits by microbial attack. PHBV specimens lost about 45% of their original weight after 45 days of exposure. During the degradation process the elastic modulus reduces less than 10%. The formation of pores and microcracks initiated at the degraded pits determines the reduction of the elongation and stress at break. However, the true stress at break is practically independent of the degradation time. No significant changes of PHBV molecular weight or crystallinity were observed during biodegradation. The polymer chain cleavage occurred only at the specimen surface and does not discriminate between crystalline and amorphous states.Fil: Hermida, Elida Beatriz. Comision Nacional de Energia Atomica. Gerencia D/area de Energia Nuclear. Gerencia Materiales.; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos; ArgentinaFil: Yashchuk, Oxana. Comision Nacional de Energia Atomica. Gerencia D/area de Energia Nuclear. Gerencia Materiales.; Argentina. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Miyazaki, Silvia Susana. Universidad de Buenos Aires. Facultad de Agronomía. Departamento de Biología Aplicada y Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

PHB-degrading Streptomyces sp. SSM 5670: isolation, characterization and PHB-accumulation

New microbial bioprospecting has become an important way to find new polyhydroxyalkanoate (PHA) producers and degraders. Poly (3-hydroxybutyrate) (PHB), the best known member of the PHAs, has received much attention because it can be degraded completely in different environments without forming any toxic products. In this contribution an actinomycete, designated strain SSM 5670, showed the better response for PHB degradation by the clear-zone method. Nevertheless, it produces PHB in low amounts (5.6% dry cell weight). According to the phylogenetic analysis the strain most similar to the PHB-degrading isolate SSM 5670 was Streptomyces omiyaensis NBRC13449. The selected isolate was characterized by its cultural, morphological and physio-biochemical features and deposited in an Argentine culture collection under the name Streptomyces omiyaensis SSM 5670.Fil: Yashchuk, Oxana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; ArgentinaFil: Miyazaki, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Biología Aplicada y Alimentos; ArgentinaFil: Hermida, Elida Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Isolation, Purification and Some Properties of an Extracellular PHBV Depolymerase from Streptomyces omiyaensis SSM 5670

–Streptomyces sp. SSM 5670 with the ability to degrade a natural polymers, polyhydroxyalkanoates (PHAs), showed a high activity of the extracellular poly (3-hydroxybutyrate-co-3-hydroxyvalerate) (PHBV) depolymerase when it was grown in a basal medium containing PHBV as the sole carbon source. The extracellular PHBV depolymerase of the organism could be purified to electrophoretic homogeneity by ion exchange column chromatography and gel filtration approximately 10.5-fold. The recovery of its activity was 20.5%. The molecular mass of the PHBV depolymerase was estimated to be 24 kDa. The maximum activity was observed near pH 7.5 and 30°C, the activity was lost at temperatures above 45°C. This enzyme might be used to promote the degradation of PHBV products buried in soil, stabilized compost or other environments around room temperature.Fil: Yashchuk, Oxana. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas; ArgentinaFil: Miyazaki, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad de Buenos Aires. Facultad de Agronomia. Departamento de Biología Aplicada y Alimentos. Area de Agroalimentos; ArgentinaFil: Hermida, Elida Beatriz. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Universidad Nacional de San Martín. Escuela de Ciencia y Tecnología; Argentin

Resource selection in an apex predator and variation in response to local landscape characteristics

Habitat loss and fragmentation represent major threats for the conservation of apex predators, such as the jaguar (Panthera onca). Investigating species’ resource selection behavior in response to landscape alteration is critical for developing relevant conservation management plans. The jaguar is found across a variety of habitats with different gradients of human disturbance, making them a good candidate to study how apex predators respond to increasing intensity of human land use. We developed resource selection models to characterize patterns of jaguar resource selection at two different spatial scales, home range (coarse) and foraging scale (fine). This analysis was based on the largest existing GPS-location dataset for jaguars (n = 40 individuals, n = 87,376 locations), spanning the species’ geographic range in Brazil and Argentina. We found that both males and females jaguars exhibited an overall preference for forests and areas close to watercourses at both the home range and foraging scale. At the foraging scale, areas of high livestock density “attracted” male jaguars. We also performed a follow-up analysis to test for context-dependent resource selection (i.e., functional responses) by relating individual behavior to local habitat characteristics. We found that jaguars in heavily-forested landscapes showed strong avoidance of non-forest. Furthermore, we found that only the individuals in closest proximity to watercourses showed positive selection for water. Our results highlight that jaguars display different patterns of resource selection in different areas, demonstrating a considerable ability to use or tolerate a wide variety of different conditions across the species geographic range. This plasticity may allow jaguars to adjust their behavior according to land use changes but also increases human-jaguar conflict and jaguar mortality, especially in areas with high livestock density.Fil: Morato, Ronaldo G.. Instituto Chico Mendes de Conservação da Biodiversidade; Brasil. Smithsonian Conservation Biology Institute. Conservation Ecology Center; Estados Unidos. Instituto Pró-carnívoros; BrasilFil: Connette, G.M.. Smithsonian Conservation Biology Institute. Conservation Ecology Center; Estados UnidosFil: Stabach, J.A.. Smithsonian Conservation Biology Institute. Conservation Ecology Center; Estados UnidosFil: De Paula, R.C.. Instituto Chico Mendes de Conservação da Biodiversidade; Brasil. Instituto Pró-carnívoros; BrasilFil: Ferraz, K.M.P.M.. Universidade de Sao Paulo; Brasil. Instituto Pró-carnívoros; BrasilFil: Kantek, D.L.Z.. Instituto Chico Mendes de Conservação da Biodiversidade; BrasilFil: Miyazaki, Silvia Susana. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentina. Instituto Chico Mendes de Conservação da Biodiversidade; BrasilFil: Pereira, T.D.C.. Instituto Chico Mendes de Conservação da Biodiversidade; BrasilFil: Silva, L.C.. Universidade Federal de Viçosa; BrasilFil: Paviolo, Agustin Javier. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: de Angelo, Carlos Daniel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: Di Bitetti, Mario Santiago. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: Cruz, María Paula. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Nordeste. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú | Universidad Nacional de Misiones. Instituto de Biología Subtropical. Instituto de Biología Subtropical - Nodo Puerto Iguazú; Argentina. Centro de Investigaciones del Bosque Atlántico; ArgentinaFil: Lima, F.. Univesidade Estadual de São Paulo; Brasil. Instituto de Pesquisas Ecológicas; BrasilFil: Cullen Jr., Laury. Univesidade Estadual de São Paulo; BrasilFil: Sana, D.A.. Instituto Pró-carnívoros; Brasil. Universidade Federal do Rio Grande do Sul; BrasilFil: Ramalho, E.E.. Instituto Pró-carnívoros; Brasil. Instituto de Desenvolvimento Sustentável Mamirauá; BrasilFil: Carvalho, M.M.. Instituto de Defesa e Preservação dos Felídeos Brasileiros; BrasilFil: da Silva, M.X.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Moraes, M.D.F.. Universidade Estadual Paulista Julio de Mesquita Filho; BrasilFil: Vogliotti, Ana. Instituto Pró-carnívoros; Brasil. Universidade Federal da Integração Latino-Americana; BrasilFil: May Jr., J.A.. Universidade do Sul de Santa Catarina; Brasil. Associação Onçafari; BrasilFil: Haberfeld, M.. Associação Onçafari; BrasilFil: Rampim, L.. Associação Onçafari; BrasilFil: Sartorello, L.. Associação Onçafari; BrasilFil: Araujo, G.R.. Universidade Federal do Mato Grosso do Sul; BrasilFil: Wittemyer, G.. State University of Colorado - Fort Collins; Estados UnidosFil: Ribeiro, M.C.. Univesidade Estadual de São Paulo; BrasilFil: Leimgruber, P.. Smithsonian Conservation Biology Institute. Conservation Ecology Center; Estados Unido

Guidelines for the use and interpretation of assays for monitoring autophagy (4th edition)

In 2008, we published the first set of guidelines for standardizing research in autophagy. Since then, this topic has received increasing attention, and many scientists have entered the field. Our knowledge base and relevant new technologies have also been expanding. Thus, it is important to formulate on a regular basis updated guidelines for monitoring autophagy in different organisms. Despite numerous reviews, there continues to be confusion regarding acceptable methods to evaluate autophagy, especially in multicellular eukaryotes. Here, we present a set of guidelines for investigators to select and interpret methods to examine autophagy and related processes, and for reviewers to provide realistic and reasonable critiques of reports that are focused on these processes. These guidelines are not meant to be a dogmatic set of rules, because the appropriateness of any assay largely depends on the question being asked and the system being used. Moreover, no individual assay is perfect for every situation, calling for the use of multiple techniques to properly monitor autophagy in each experimental setting. Finally, several core components of the autophagy machinery have been implicated in distinct autophagic processes (canonical and noncanonical autophagy), implying that genetic approaches to block autophagy should rely on targeting two or more autophagy-related genes that ideally participate in distinct steps of the pathway. Along similar lines, because multiple proteins involved in autophagy also regulate other cellular pathways including apoptosis, not all of them can be used as a specific marker for bona fide autophagic responses. Here, we critically discuss current methods of assessing autophagy and the information they can, or cannot, provide. Our ultimate goal is to encourage intellectual and technical innovation in the field