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We evaluated the influence of areas with dissimilar upwelling intensity along the Humboldt Current System on the morphological variation of the economically important sea silverside Odontesthes regia by using geometric morphometric (GM) and meristic data of populations sampled off Northern Peru, Central Peru, Southern Peru-Northern Chile, and Central-Southern Chile (CSCH). Multivariate analyses of variance, a UPGMA tree, and discriminant analyses of meristic counts separated CSCH individuals, which had slightly higher numbers of gill rakers and radius of the anal fin. Permutation tests and canonical variate analyses of GM data distinguished all populations and highlighted deformations in the head and fins. Variations in GM and meristic analyses were significantly correlated with values of the sea surface temperature and surface chlorophyll-a concentrations. Morphological differences among populations might be associated with the spatial coastal upwelling dynamic of the Humboldt Current System, which highlights the role that this system plays in relation to the phenotypic variation of fish.

The use of microorganisms in mining processes is a technology widely employed around the world. Leaching bacteria are characterized by having resistance mechanisms for several metals found in their acidic environments, some of which have been partially described in the Acidithiobacillus genus (mainly on ferrooxidans species). However, the response to copper has not been studied in the psychrotolerant Acidithiobacillus ferrivorans strains. Therefore, we propose to elucidate the response mechanisms of A. ferrivorans ACH to high copper concentrations (0&ndash, 800 mM), describing its genetic repertoire and transcriptional regulation. Our results show that A. ferrivorans ACH can grow in up to 400 mM of copper. Moreover, we found the presence of several copper-related makers, belonging to cop and cus systems, as well as rusticyanins and periplasmatic acop protein in the genome. Interestingly, the ACH strain is the only one in which we find three copies of copB and copZ genes. Moreover, transcriptional expression showed an up-regulation response (acop, copZ, cusA, rusA, and rusB) to high copper concentrations. Finally, our results support the important role of these genes in A. ferrivorans copper stress resistance, promoting the use of the ACH strain in industrial leaching under low temperatures, which could decrease the activation times of oxidation processes and the energy costs.

Hydrothermal systems are ideal to understand how microbial communities cope with challenging conditions. Lirima, our study site, is a polyextreme, high-altitude, hydrothermal ecosystem located in the Chilean Andean highlands. Herein, we analyze the benthic communities of three nearby springs in a gradient of temperature (42&ndash, 72 &deg, C represented by stations P42, P53, and P72) and pH, and we characterize their microbial diversity by using bacteria 16S rRNA (V4) gene metabarcoding and 16S rRNA gene clone libraries (bacteria and archaea). Bacterial clone libraries of P42 and P53 springs showed that the community composition was mainly represented by phototrophic bacteria (Chlorobia, 3%, Cyanobacteria 3%, at P42, Chlorobia 5%, and Chloroflexi 5% at P53), Firmicutes (32% at P42 and 43% at P53) and Gammaproteobacteria (13% at P42 and 29% at P53). Furthermore, bacterial communities that were analyzed by 16S rRNA gene metabarcoding were characterized by an overall predominance of Chloroflexi in springs with lower temperatures (33% at P42), followed by Firmicutes in hotter springs (50% at P72). The archaeal diversity of P42 and P53 were represented by taxa belonging to Crenarchaeota, Diapherotrites, Nanoarchaeota, Hadesarchaeota, Thaumarchaeota, and Euryarchaeota. The microbial diversity of the Lirima hydrothermal system is represented by groups from deep branches of the tree of life, suggesting this ecosystem as a reservoir of primitive life and a key system to study the processes that shaped the evolution of the biosphere.

Relatively little is known about the microbial communities present in natural environments that meet physico-chemical conditions for the development of potential leaching microorganisms such as thermal ecosystems from the Chilean Altiplano. Thermophilic leaching enrichments were obtained and identified from a high altitude solfataric pound in Lirima hot springs in the Chilean Altiplano. This ecosystem is characterized by hot underground freshwaters, enriched in sulfur compounds showing pH from neutral to acidic. Microbial diversity has been scarcely explored here, and preliminary results demonstrate that hydrothermal pounds are represented by thermophilic anaerobic and acidophilic taxa. Thermophilic leaching cultures in shake flasks were obtained using ferrous iron and pyrite as energy source. The presence of Bacteria and Archaea in oxidizing enrichments was determined by PCR amplification of 16S rRNA genes. A preliminary analysis of microbial diversity using massive sequencing revealed that Bacteria were more abundant than Archaea in both enrichments. Specifically for the iron-oxidizing culture, the majority of the sequences clustered within the Proteobacteria phylum (79%). Among Proteobacteria, the proportion of Betaproteobacteria (42.2%) and Gammaproteobacteria (21.27%) was much higher than that of Alphaproteobacteria (15.5%). Within the Betaproteobacteria class, the most frequent genus was Leptothrix-like. Similar results were obtained for the pyrite oxidizing culture. Interestingly, this study shows the presence of microorganisms close to the Leptothrix genus under low pH conditions (1.7-2.8) and their capacity to grow at high temperatures with ferrous iron or pyrite as sole energy source

The Chub mackerel (Teleostei: Scombridae) supports an important fishery in the Southeastern Pacific, however, its population genetics status is currently unknown. In the present study the population genetic structure, gene flow and historical demography of this resource in the Northern Humboldt Current System were examined. Samples were collected between 2103 and 2014 from three fishing points off the Peruvian coast (Paita, Ventanilla and Ilo) and analyzed using mitochondrial D-Loop region sequences. A total of 29 polymorphic sites and 35 haplotypes were found in 72 individuals. Moderate haplotype diversity and very low levels of nucleotide diversity were found. Analysis of gene flow showed high levels of connectivity among sampling areas. Analysis of molecular variance, pairwise comparisons and genetic differentiation tests confirmed the lack of genetic structuring. These analyses suggest that analyzed sampling locations can be considered as a single gene pool. Migratory behavior, the high dispersal potential of early stages and the lack of oceanographic barriers can explain its genetic homogeneity along the Peruvian sea. The historical demography was also examined. Neutrality testing, mismatch distribution and Bayesian skyline plot suggested a population expansion scenario that took place during the Late Pleistocene. This study provides novel information about population genetics of the chub mackerel from the Southeastern Pacific., La caballa, Scomber japonicus soporta una pesquería importante en el Pacífico Sudeste, sin embargo, su genética de poblaciones se desconoce actualmente. En el presente estudio se examinó la estructura genética, el flujo génico y la demografía histórica de esta especie en la parte norte del Sistema de la Corriente de Humboldt. Las muestras fueron colectadas en los veranos del 2013 y 2014 en tres puntos de desembarco de pesca (Paita, Ventanilla e Ilo) cubriendo 12 grados de latitud frente a la costa peruana. Se secuenció un segmento de 532 pb de la región control mitocondrial en 72 individuos, el cual permitió detectar un total de 29 sitios polimórficos, 35 haplotipos, niveles moderados altos de diversidad haplotípica (0.793 – 0.969) y muy bajos niveles de diversidad nucleotídica (0.004 – 0.008). El análisis de flujo génico mostró altos niveles de conectividad entre las poblaciones en las áreas de muestreo. El análisis de varianza molecular (ФST = 0.00868, P = 0.1837), las comparaciones ФST a pares de poblaciones y las pruebas de diferenciación genética confirmaron la carencia de estructuración genética entre las tres localidades. Estos análisis sugieren que los sitios de muestreo analizados pueden ser considerados como un solo grupo genético. El comportamiento migratorio, el alto potencial de dispersión de los estadios tempranos de desarrollo y la ausencia de barreras oceanográficas pueden explicar su homogeneidad genética a lo largo del mar peruano. También se examinó la demografía histórica. Las pruebas de neutralidad, la distribución mismatch y el Bayesian Skyline Plot sugirieron un escenario de expansión poblacional que tuvo lugar durante el Pleistoceno Superior. Este estudio provee información nueva con respecto a la genética de poblaciones de la caballa en el Pacífico Sudeste.

Mesophilic iron and sulfur-oxidizing acidophiles are commonly used for the extraction of base metals from low-grade sulfide ores in some copper Chilean mines. However, relatively little is known about their activities in cold environments. Some natural ecosystems present in the Andes Mountains, such as the Chilean Altiplano, meet environmental conditions for the growth of psychrotolerant leaching microorganisms. In this work, we obtained enrichment cultures of iron- and sulfur-oxidizing microorganisms from an acid river in the Chilean Altiplano. Molecular identification was performed using PCR products of bacterial 16S rRNA clone libraries, and the sequences analysis revealed the presence of a microorganism related to the recently described psychrotolerantAcidithiobacillus ferrivorans. TheAcidithiobacillusstrain was able to grow at temperatures ranging between 4 and 30°C, and pH values ranged between 1.7 and 2.5. According to the energy sources, this microorganism was able to grow using ferric iron, sulfur, thiosulfate and tetrathionate. Optimal growth was observed in presence of ferric ion, where the culture reached a potential redox value of 600 mV and a cellular number of 3×107cells/mL. Molecular analysis of variants of gene encoding for rusticyanin showed thatrusBgene was amplified fromA. ferrivoransstrain and no PCR product was obtained for therusAgene. Our description is consistent with data previously reported forA. ferrivoransstrains. Finally, results of this study highlight the importance and potential of novel native bacterial species proficient in mineral oxidation under low-temperature conditions.

BackgroundGreat saphenous vein (GSV) reflux is the most frequent form of venous insufficiency in symptomatic patients and is commonly responsible for varicose veins of the lower extremity. This non-randomized prospective controlled study was designed to test the hypothesis that 1) endovenous laser treatment is more effective than foam sclerotherapy in the closure of the refluxing GSV (as measured by degree of great saphenous vein reflux and venous clinical severity score changes) and 2) to record the associated complications of echo-guided endovenous chemical ablation with foam and endovenous laser therapy for the treatment of great saphenous vein reflux and to further identify risk factors associated with treatment failure.MethodsBetween January 1, 2006 and June 25, 2006, patients seeking treatment of varicose veins at a private practice of vascular medicine were assessed for the study. Inclusion criteria were: 1) presence of great saphenous vein reflux and 2) C2-6, Epr, A s, according to the CEAP classification. The selected patients consented into the study and were allowed to choose between foam (53 patients) or laser (45 patients) treatment. Duplex examinations were performed prior to treatment and at seven and 14 days, four weeks, six months, and one year after treatment. Venous clinical severity score was assessed pre-treatment and at one year post-procedure.ResultsThe cohorts showed no statistically significant differences in age, sex, clinical and anatomical presentation, great saphenous vein diameter, and venous clinical severity score before the treatments. After one year follow up, occlusion of the great saphenous vein was confirmed in 93.4% (42/45) of limbs studied in the laser group and 77.4% (41/53) of limbs in the foam group (P < .0465). Venous clinical severity score significantly improved in both groups (P < .0001). Procedure associated pain was higher in the laser group (P < .0082). Induration, phlebitis, and ecchymosis were the most common complications. Logistical regression and subgroups analysis shown that a larger great saphenous vein diameter measured before treatment was associated with treatment failure in the foam (odds ratio 1.68, 95% CI 1.24-2.27, P < .0008) and in the laser group (odds ratio 1.91, 95% CI 1.02-3.59, P < .0428). A 90% treatment success is predicted for veins 90%. A larger patient cohort followed and compared over a longer period of time would be required to confirm these findings.

Some results of the analysis of the pictures taken along the performance of the Análisis de Propiedades Inerciales de Sólidos, Analysis of the Inertia Properties of Solid Bodies (APIS) experiment carried out in the Cervantes mission on board ISS, are presented. APIS was an educational experiment devoted to take advantage of the unique conditions of absence of relative gravity forces of a space platform such as ISS, to show some of the characteristics of the free rotational motion of a solid body, which are impossible to carry out on earth. This field of experimental research has application to aerospace engineering science (e.g. attitude control of spacecrafts), to astrophysical sciences (e.g. state of rotation and tumbling motions of asteroids) and to engineering education. To avoid the effect of the ambient atmosphere loads on the motion, the test body is placed inside a sphere, which reduces the effect of the aerodynamic forces to just friction. The drastic reduction of the effect of the surrounding air during the short duration of the experimental sequences allows us to compare the actual motion with the known solutions for the solid body rotation in vacuum. In this paper, some selected, relevant sequences of the sphere enclosing a body with a nominal cylindrical inertia tensor, put into rotation by the astronaut, are shown; the main problems to extract the information concerning the characteristic parameters of the motion are outlined, and some of the results obtained concerning the motion of the test probe are included, which show what seems to be a curious and unexpected solution of the Euler equations for the solid body rotation in vacuum, without energy dissipation, when the angular momentum is almost perpendicular to the axisymmetry axis.

Microorganisms are used to aid the extraction of valuable metals from low-grade sulfide ores in mines worldwide, but relatively little is known about this process in cold environments. This study comprises a preliminary analysis of the bacterial diversity of the polyextremophilic acid River Aroma located in the Chilean Altiplano, and revealed that Betaproteobacteria was the most dominant bacterial group (Gallionella-like and Thiobacillus-like). Taxa characteristic of leaching environments, such Acidithiobacillus and Leptospirillum, were detected at low abundances. Also, bacteria not associated with extremely acidic, metal-rich environments were found. After enrichment in iron- and sulfur-oxidizing media, we isolated and identified a novel psychrotolerant Acidithiobacillus ferrivorans strain ACH. This strain can grow using ferrous iron, sulfur, thiosulfate, tetrathionate and pyrite, as energy sources. Optimal growth was observed in the presence of pyrite, where cultures reached a cell number of 6.5 · 10(7) cells mL(-1). Planktonic cells grown with pyrite showed the presence of extracellular polymeric substances (10 °C and 28 °C), and a high density of cells attached to pyrite grains were observed at 10 °C by electron microscopy. The attachment of cells to pyrite coupons and the presence of capsular polysaccharides were visualized by using epifluorescence microscopy, through nucleic acid and lectin staining with Syto(®)9 and TRITC-Con A, respectively. Interestingly, we observed high cell adhesion including the formation of microcolonies within 21 days of incubation at 4 °C, which was correlated with a clear induction of capsular polysaccharides production. Our data suggests that attachment to pyrite is not temperature-dependent in At. ferrivorans ACH. The results of this study highlight the potential of this novel psychrotolerant strain in oxidation and attachment to minerals under low-temperature conditions.