Bacterial community of sediments under the Eastern Boundary Current System shows high microdiversity and a latitudinal spatial pattern.

The sediments under the Oxygen Minimum Zone of the Eastern Boundary Current System (EBCS) along Central-South Peru and North-Central Chile, known as Humboldt Sulfuretum (HS), is an organic-matter-rich benthic habitat, where bacteria process a variety of sulfur compounds under low dissolved-oxygen concentrations, and high sulfide and nitrate levels. This study addressed the structure, diversity and spatial distribution patterns of the HS bacterial community along Northern and South-Central Chile using 16S rRNA gene amplicon sequencing. The results show that during the field study period, the community was dominated by sulfur-associated bacteria. Indeed, the most abundant phylum was Desulfobacterota, while Sva0081 sedimentary group, of the family Desulfosarcinaceae (the most abundant family), which includes sulfate-reducer and H2 scavenger bacteria, was the most abundant genus. Furthermore, a spatial pattern was unveiled along the study area to which the family Desulfobulbaceae contributed the most to the spatial variance, which encompasses 42 uncharacterized amplicon sequence variants (ASVs), three assigned to Ca. Electrothrix and two to Desulfobulbus. Moreover, a very high microdiversity was found, since only 3.7% of the ASVs were shared among localities, reflecting a highly diverse and mature community.

Genomic features of "Candidatus Venteria ishoeyi", a new sulfur-oxidizing macrobacterium from the Humboldt Sulfuretum off Chile.

The Humboldt Sulfuretum (HS), in the productive Humboldt Eastern Boundary Current Upwelling Ecosystem, extends under the hypoxic waters of the Peru-Chile Undercurrent (ca. 6°S and ca. 36°S). Studies show that primeval sulfuretums held diverse prokaryotic life, and, while rare today, still sustain species-rich giant sulfur-oxidizing bacterial communities. We here present the genomic features of a new bacteria of the HS, "Candidatus Venteria ishoeyi" ("Ca. V. ishoeyi") in the family Thiotrichaceae.Three identical filaments were micro-manipulated from reduced sediments collected off central Chile; their DNA was extracted, amplified, and sequenced by a Roche 454 GS FLX platform. Using three sequenced libraries and through de novo genome assembly, a draft genome of 5.7 Mbp, 495 scaffolds, and a N50 of 70 kbp, was obtained. The 16S rRNA gene phylogenetic analysis showed that "Ca. V. ishoeyi" is related to non-vacuolate forms presently known as Beggiatoa or Beggiatoa-like forms. The complete set of genes involved in respiratory nitrate-reduction to dinitrogen was identified in "Ca. V. ishoeyi"; including genes likely leading to ammonification. As expected, the sulfur-oxidation pathway reported for other sulfur-oxidizing bacteria were deduced and also, key inorganic and organic carbon acquisition related genes were identified. Unexpectedly, the genome of "Ca. V. ishoeyi" contained numerous CRISPR repeats and an I-F CRISPR-Cas type system gene coding array. Findings further show that, as a member of an eons-old marine ecosystem, "Ca. V. ishoeyi" contains the needed metabolic plasticity for life in an increasingly oxygenated and variable ocean.

Sulfur-cycling fossil bacteria from the 1.8-Ga Duck Creek Formation provide promising evidence of evolution's null hypothesis.

The recent discovery of a deep-water sulfur-cycling microbial biota in the ∼ 2.3-Ga Western Australian Turee Creek Group opened a new window to life's early history. We now report a second such subseafloor-inhabiting community from the Western Australian ∼ 1.8-Ga Duck Creek Formation. Permineralized in cherts formed during and soon after the 2.4- to 2.2-Ga "Great Oxidation Event," these two biotas may evidence an opportunistic response to the mid-Precambrian increase of environmental oxygen that resulted in increased production of metabolically useable sulfate and nitrate. The marked similarity of microbial morphology, habitat, and organization of these fossil communities to their modern counterparts documents exceptionally slow (hypobradytelic) change that, if paralleled by their molecular biology, would evidence extreme evolutionary stasis.

Microbial life in a fjord: metagenomic analysis of a microbial mat in Chilean patagonia.

The current study describes the taxonomic and functional composition of metagenomic sequences obtained from a filamentous microbial mat isolated from the Comau fjord, located in the northernmost part of the Chilean Patagonia. The taxonomic composition of the microbial community showed a high proportion of members of the Gammaproteobacteria, including a high number of sequences that were recruited to the genomes of Moritella marina MP-1 and Colwelliapsycherythraea 34H, suggesting the presence of populations related to these two psychrophilic bacterial species. Functional analysis of the community indicated a high proportion of genes coding for the transport and metabolism of amino acids, as well as in energy production. Among the energy production functions, we found protein-coding genes for sulfate and nitrate reduction, both processes associated with Gammaproteobacteria-related sequences. This report provides the first examination of the taxonomic composition and genetic diversity associated with these conspicuous microbial mat communities and provides a framework for future microbial studies in the Comau fjord.

Gypsum-permineralized microfossils and their relevance to the search for life on Mars.

Orbital and in situ analyses establish that aerially extensive deposits of evaporitic sulfates, including gypsum, are present on the surface of Mars. Although comparable gypsiferous sediments on Earth have been largely ignored by paleontologists, we here report the finding of diverse fossil microscopic organisms permineralized in bottom-nucleated gypsums of seven deposits: two from the Permian (∼260 Ma) of New Mexico, USA; one from the Miocene (∼6 Ma) of Italy; and four from Recent lacustrine and saltern deposits of Australia, Mexico, and Peru. In addition to presenting the first report of the widespread occurrence of microscopic fossils in bottom-nucleated primary gypsum, we show the striking morphological similarity of the majority of the benthic filamentous fossils of these units to the microorganisms of a modern sulfuretum biocoenose. Based on such similarity, in morphology as well as habitat, these findings suggest that anaerobic sulfur-metabolizing microbial assemblages have changed relatively little over hundreds of millions of years. Their discovery as fossilized components of the seven gypsiferous units reported suggests that primary bottom-nucleated gypsum represents a promising target in the search for evidence of past life on Mars. Key Words: Confocal laser scanning microscopy-Gypsum fossils-Mars sample return missions-Raman spectroscopy-Sample Analysis at Mars (SAM) instrument-Sulfuretum.

New communities of large filamentous sulfur bacteria in the eastern South Pacific.

New complex communities of morphologically diverse and sometimes abundant large, multicellular, filamentous bacteria were discovered in the oxygen-deficient, organically laden, shelf sediments under the oxygen minimum zone off the coast of the eastern Pacific, i.e., off the coasts of central and northern Chile; central and northern Perú; Roca Redonda, Galápagos Archipielago, Ecuador; and off the Pacific coasts of Panamá and Costa Rica. Similar microbial communities were also observed in the reduced layer of a muddy-sand beach adjacent to a mangrove swamp on Coiba Island, Pacific Panamá, and in the organically laden bottom underneath a salmon culture pen in southern Chile (region X). Of varying morphology, the diameters of the bacteria range from 1 to 10 mum, and their lengths from around 10 mum to usually several hundreds but at times several thousands of micrometers. The new filamentous bacterial component is at least one order of magnitude smaller than the also multicellular "megabacteria" Thioploca spp. and Beggiatoa spp., and is collectively referred to as "macrobacteria". A recent review only mentioned a few of these free-living filamentous bacteria, remarking on their scarcity despite the obvious advantages of a large size. This prokaryote size-window has been rarely investigated optically by researchers; thus, assemblages that appear to have had world-wide distribution probably since pre-Cambrian times have been overlooked.

Usos clínicos de neurolépticos orales y de depósito / Clinical uses of oral and depot neuroleptics

Se efectúa una revisión de las características farmacológicas y del uso clínico de los neurolépticos orales y de depósito más utilizados. Se analizan las principales causas de fracaso terapéutico, enfatizando los factores de riesgo de las complicaciones de mayor importancia y en particular de las diskinesias tardías y del síndrome neuroléptico maligno

Evaluación del apoyo afectivo en estudiantes de medicina con la prueba de Apgar de Smilksteina / Assesment of effect support in students of medicine through Smilkstein's Apgar tests

La evaluación rápida del apoyo afectivo individual es necesaria y útil en la práctica médica. Esta se ha hecho, en adolescentes, aplicando el Apgar Familiar y el de las amistades de Smilkstein. El presente trabajo mide, con estos instrumentos, el apoyo familiar y de las amistades en estudiantes de medicina, quienes por su sistema de estudio se ven sometidos a una fuerte presión curricular. Ambos Apgar se aplicaron a 499 alumnos correspondientes al 90,7% del total de 550 de la División de Ciências Médicas Occidente de la Universidad de Chile. El 39,1% de ellos eran menores de 21 años (n = 195) y el 40% (n = 200) eran mujeres. Las encuestas se realizaron entre Octubre de 1986 y Mayo de 1987. El Apgar satisfactorio (8 puntos o más) se encontró en el 59,9% de los casos encuestados en AF y AA. El intermedio (4-7 puntos) fue 32,3% en el Apgar familiar y 35,5% en el Apgar de las amistades. El bajo (-4 puntos) fue 7,8% en Apgar familiar y 4,6% en Apgar de las amistades (Diferencia significativa). El Apgar familiar bajo fue 9,4% en hombres y 5,5% en mujeres. El Apgar familiar bajo fue más frecuente que el Apgar de amistades bajo en cinco de los siete cursos y dos cursos destacaron por tener más de 10% de Apgar familiar bajo. Las mujeres tuvieron frecuencia significativamente más alta de Apgar de amistades satisfactorio. En total de 499 estudiantes un 19,2% tuvo Apgar familiar inferior a 6 puntos; cifra significativamente menor que la encontrada en adolescentes del área Oriente de Santiago. Se post