Comparison of covalent and in situ immobilization of Candida antarctica lipase A on a flexible nanoporous material.

In this study, Candida antarctica lipase A, which has a unique applicability for the conversion of highly branched and bulky substrates, was subjected to immobilization on the flexible nanoporous MIL-53(Fe) by two approaches: covalent coupling and in situ immobilization method. The pre-synthesized support under ultrasound irradiation was incubated with N,N-dicyclohexylcarbodiimide to mediate the covalent attachment between the carboxylic groups on the support surface and amino groups of enzyme molecules. The in situ immobilization in which the enzyme molecules directly were embedded into the metal-organic framework was performed under mild operating conditions in a facile one-step manner. Both immobilized derivatives of the enzyme were characterized by scanning electron microscopy, X-ray diffraction, thermogravimetric analysis, FT-IR spectra, and energy-dispersive X-ray spectroscopy. In the in situ immobilization method, the enzyme molecules were efficiently encapsulated within the support with a high loading capacity (220 ± 5 mg/g support). On the other hand, the covalent attachment resulted in immobilizing much lower concentrations of the enzyme (20 ± 2.2 mg/g support). Although both immobilized derivatives of lipase showed broader pH and temperature tolerance relative to the soluble enzyme, the biocatalyst, which was prepared through in situ method, was more stable at elevated temperatures than the covalently immobilized lipase. Furthermore, in situ immobilized derivatives of Candida antarctica lipase A could be efficiently reused for at least eight cycles (> 70% of retained activity). In contrast, its covalently immobilized counterpart showed a drastic decrease in activity after five cycles (less than 10% of retained activity at the end of 6 rounds).

Debaryomyces hansenii F39A as biosorbent for textile dye removal.

Many industries generate a considerable amount of wastewater containing toxic and recalcitrant dyes. The main objective of this research was to examine the biosorption capacity of Reactive Blue 19 and Reactive Red 141 by the Antarctic yeast Debaryomyces hansenii F39A biomass. Some variables, including pH, dye concentration, amount of adsorbent and contact time, were studied. The equilibrium sorption capacity of the biomass increased with increasing initial dye concentration up to 350mg/l. Experimental isotherms fit the Langmuir model and the maximum uptake capacity (qmax) for the selected dyes was in the range of 0.0676-0.169mmol/g biomass. At an initial dye concentration of 100mg/l, 2g/l biomass loading and 20±1°C, D. hansenii F39A adsorbed around 90% of Reactive Red 141 and 50% of Reactive Blue 19 at pH 6.0. When biomass loading was increased (6g/l), the uptake reached up to 90% for Reactive Blue 19. The dye uptake process followed a pseudo-second-order kinetics for each dye system. As seen throughout this research study, D. hansenii has the potential to efficiently and effectively remove dyes in a biosorption process and may be an alternative to other costly materials.

Observations of Buried Lake Drainage on the Antarctic Ice Sheet.

Between 1992 and 2017, the Antarctic Ice Sheet (AIS) lost ice equivalent to 7.6 ± 3.9 mm of sea level rise. AIS mass loss is mitigated by ice shelves that provide a buttress by regulating ice flow from tributary glaciers. However, ice-shelf stability is threatened by meltwater ponding, which may initiate, or reactivate preexisting, fractures, currently poorly understood processes. Here, through ground penetrating radar (GPR) analysis over a buried lake in the grounding zone of an East Antarctic ice shelf, we present the first field observations of a lake drainage event in Antarctica via vertical fractures. Concurrent with the lake drainage event, we observe a decrease in surface elevation and an increase in Sentinel-1 backscatter. Finally, we suggest that fractures that are initiated or reactivated by lake drainage events in a grounding zone will propagate with ice flow onto the ice shelf itself, where they may have implications for its stability.

Gerenciamento do comportamento seguro para manutenção da vida na Estação Antártica Brasileira / Management of safe behavior to maintain life at the Brazilian Antarctic Station / Gestión del comportamiento seguro para mantenimiento de la vida en la Estación Antártica Brasileña

Em regiões polares, o gerenciamento do comportamento seguro é fundamental às operações de abastecimento para manutenção da vida (OPAMV). O objetivo deste estudo foi analisar aspectos do comportamento seguro nas OPAMV na Estação Antártica Comandante Ferraz (EACF) durante o inverno. A pesquisa foi descritiva, de abordagem qualitativa e procedimento de triangulação de observações e levantamento de dados. Foram realizadas observações da rotina de trabalho e entrevistas com a tripulação da Força Aérea Brasileira (n=12) e com o grupo-base (GB) da EACF (N=30). A autonomia do GB no trabalho minimiza o impacto das características extremas do inverno. As OPAMV na EACF repercutem diretamente na subsistência e na manutenção de laços afetivos externos. O estudo do gerenciamento do comportamento seguro aponta fatores com potencial de reduzirem riscos de acidentes e adoecimentos, impactando na permanência salutar no contexto. O aperfeiçoamento dos estudos pode contribuir para a atenção dos fatores humanos em condições polares.

In polar regions, the management of safe behavior is fundamental to supply operations to maintain life (OPML). The objective of this study was to control OPML at the Comandante Ferraz Antarctic Station during the winter. The research was descriptive, with a qualitative approach and the procedure of triangulation of observations and survey. Routine questions and interviews with the crew (n = 12) and with the base group (BG) of Ferraz Station (N = 30) were conducted. The autonomy of the BG in the work minimizes the impact of extreme winter characteristics. OPML at Ferraz Station has direct repercussions on subsistence and on the maintenance of external affective bonds. The study of safe behavior points to factors with the potential to reduce the risks of accidents and illness, having impact on healthy permanence in this context. Improvement of these studies can contribute to attending to human factors in polar conditions.

En regiones polares, la gestión del comportamiento seguro es fundamental para las operaciones de aprovisionamiento y el mantenimiento de la vida (OPAMV). El objetivo de este estudio fue analizar aspectos del comportamiento seguro en las OPAMV en la Estación Antártica Comandante Ferraz (EACF) durante el invierno. La investigación fue descriptiva, cualitativa y de triangulación de observaciones y datos. Se realizaron observaciones de rutina de trabajo y entrevistas con la tripulación de la Fuerza Aérea Brasileña (n = 12) y con el grupo base (GB) de la EACF (N = 30). La autonomía del GB minimiza el impacto de las características extremas del invierno. Las OPAMV en la EACF repercuten directamente en la subsistencia y mantenimiento de vínculos afectivos externos. El estudio de la gestión del comportamiento seguro indica riesgos de accidentes y enfermedades, afectando a la permanencia saludable en el contexto. El perfeccionamiento de los estudios puede contribuir a la atención de los factores humanos en condiciones polares.

A method to estimate pre-exploitation population size.

Antarctic fur seals (Arctocephalus gazella) were commercially exploited on the subantarctic island of South Georgia for over 100 years and nearly driven to extinction. Since the cessation of harvesting, however, their populations have rebounded, and they are now often considered a nuisance species whose impact on the terrestrial landscape should be mitigated. Any evaluation of their current population requires the context provided by their historic, pre-exploitation abundance, lest ecologists fall prey to shifting baseline syndrome in which their perspective on current abundance is compared only with an altered state resulting from past anthropogenic disturbance. Estimating pre-exploitation abundance is critical to defining species recovery and setting recovery targets, both of which are needed for the International Union for the Conservation of Nature's recent efforts to develop a green list of recovering species. To address this issue, we reconstructed the South Georgia fur seal harvest from 1786 to 1908 from ship logbooks and other historical records and interpolated missing harvest data as necessary with a generalized linear model fit to the historical record. Using an approximate Bayesian computation framework, harvest data, and a stochastic age-structured population model, we estimated the pre-exploitation abundance of Antarctic fur seals on South Georgia was 2.5 million females (95% CI 1.5-3.5 million). This estimate is similar to recent abundance estimates, and suggests current populations, and the ecological consequences of so many fur seals on the island, may be similar to conditions prior to human harvest. Although the historic archive on the fur sealing era is unavoidably patchy, the use of archival records is essential for reconstructing the past and, correspondingly, to understanding the present. Article impact statement: Defining species recovery requires an understanding of baseline population state, which can be estimated through statistical methods.

Un Método para Estimar el Tamaño Poblacional Previo a la Explotación Resumen La foca antártica (Arctocephalus gazella) fue explotada comercialmente en la isla subantártica de Georgia del Sur durante más de 100 años y esto casi la llevó a la extinción. Sin embargo, desde que se detuvo la captura de esta especie, su población se ha recuperado y actualmente se le considera con frecuencia una especie molesta cuyo impacto sobre el paisaje terrestre debería ser mitigado. Cualquier evaluación de la población actual requiere del contexto proporcionado por su abundancia histórica previa a la explotación para así evitar que los ecólogos sufran del síndrome de la línea base cambiante, en el cual la perspectiva de la abundancia contemporánea se compara solamente con un estado alterado resultante de perturbaciones antropogénicas pasadas. La estimación de la abundancia previa a la explotación es sumamente importante para definir la recuperación de una especie y para establecer los objetivos de recuperación, ambos requisitos necesarios para los esfuerzos recientes de la Unión Internacional para la Conservación de la Naturaleza (UICN) por desarrollar una lista verde de especies en recuperación. Para tratar este tema reconstruimos la captura de la foca antártica en la isla de Georgia del Sur desde 1786 hasta 1908 a partir de bitácoras de navíos y otros registros históricos e interpolamos los datos faltantes de las capturas conforme fuera necesario con un modelo lineal generalizado que se ajustara al registro histórico. Con un marco de trabajo de cómputo bayesiano aproximado, los datos de las capturas y un modelo poblacional estocástico estructurado por edades estimamos que la abundancia previa a la explotación de la foca antártica en la isla de Georgia del Sur era de 2.5 millones de hembras (95% IC1.5 - 3.5 millones). Este estimado es similar a las estimaciones recientes de abundancia y sugiere que las poblaciones actuales y las consecuencias ecológicas de la presencia de tantas focas en la isla podría ser similar a las condiciones previas a la captura. Aunque el archivo histórico sobre la era de la caza de focas antárticas presenta vacíos inevitablemente, el uso de registros archivados es esencial para la reconstrucción del pasado y, correspondientemente, para entender el presente.

Persistent organic pollutants in blubber of fin whales (Balaenoptera physalus) from the Southern Ocean.

Persistent organic pollutants (POPs) were analyzed in eighteen blubber samples biopsied from fin whales (Balaenoptera physalus) during the feeding season near the Antarctic Peninsula in the summer of 2013. POP content (in ng g-1 lipid weight) ranged from 46.4 to 708 for polychlorinated biphenyls (∑PCBs), 6.77 to 123 for hexachlorobenzene (HCB), 10.1 to 489 for dichlorodiphenyltrichloroethane and derivatives (∑DDTs), 5.38 to 52.8 for hexachlorocyclohexanes (∑HCH) and <0.40 to 2.54 for polybrominated diphenyl ethers (∑PBDEs). The presence of those compounds in Southern Ocean fin whales is related to long-range transport and their diet based mainly on euphausiids (krill). Their contents were much lower compared to the same species in other locations, especially in the Northern Hemisphere, presumably due to differences in trophic position and the proximity of POP sources and contamination of prey items.

Coping e padrões biológicos de sono em expedicionários antárticos / Coping and biological standards of sleeping in Antarctic expedicionaries

O objetivo deste estudo foi avaliar a variação das estratégias de coping e padrões de sono em 13 expedicionários do sexo masculino da aviação naval no início e ao final de uma expedição de verão à Antártica. Para investigar as variáveis de coping e de sono foram utilizadas a escala BriefCOPE, um questionário de ritmos biológicos e um formulário sociodemográfico para controle de variáveis. As estratégias de coping focadas na emoção do tipo disfuncional aumentaram de maneira significativa ao longo da exposição, e não houve relação entre as alterações nos padrões de sono e as estratégias de coping no início e no fim da exposição ao ambiente. A atenção a fatores psicológicos em ambientes polares pode prevenir acidentes no contexto.

The objective of this study was to evaluate the variation of coping strategies and sleep patterns in 13 male naval aviation expeditioners at the beginning and end of a summer expedition to Antarctica. To investigate the coping and sleep variables, the BriefCOPE scale was used, a biological rhythm questionnaire and a sociodemographic form to control variables. Emotion-focused coping strategies of the dysfunctional type increased significantly throughout the exposure and there was no relationship between changes in sleep patterns and coping strategies between the onset and end of exposure to the environment. Attention to psychological factors in polar environments can prevent accidents in context.

Skin protective effects of an antipollution, antioxidant serum containing Deschampsia antartica extract, ferulic acid and vitamin C: a controlled single-blind, prospective trial in women living in urbanized, high air pollution area.

Introduction: Air pollution causes skin damage and favors skin aging processes such as dark spots and wrinkles, through oxidative stress. Pollutant substances accelerate skin aging through a specific activation of intracellular receptors called AhR (aryl-hydrocarbon receptors). Deschampsia antartica aqueous extract (DAE) has shown to counteract the pollutant-induced AhR activation. Ferulic acid (FA) and vitamin C (VC) are potent antioxidant substances. A serum containing DAE/FA/VC has been recently developed. So far, no clinical data are available regarding the protective actions of this serum against the detrimental effects of air pollution on the skin. Objective: We conducted a prospective, single-blind, 28-day study to assess efficacy and protective effects against air pollution skin damage of a new serum containing Deschampsia antartica extract. Materials and methods: Twenty, photo type I-III, women (mean age 42 years) with at least three dark spots on the face, living in a homogenous urbanized, high pollution area (Rome) were evaluated. The objectives of the study were to evaluate the effects of treatment on skin barrier function, assessed by transepidermal water loss (TEWL) measurement (Tewameter), the effect on dark spots, evaluated by means of colorimetry (Colorimeter CL 400), and the effect on squalene peroxide (SQOOH)/squalene (SQ) skin ratio assessed with face swabs. Results: The trial was conducted between November 20 and December 19, 2018. In comparison with baseline, the product induced a significant improvement of skin hydration (-19% of TEWL), a significant improvement of dark spots (+7%) and a significant improvement of SQOOH/SQ ratio (-16%). The product was evaluated very well by >90% of the treated subjects regarding cosmetic acceptability. Discussion: A serum containing DAE/FA/VC has shown to improve skin barrier function, to reduce dark spots and to counteract the skin oxidative stress in women living in high pollution urban area.

A multi-enzyme cascade reaction for the production of 6-hydroxyhexanoic acid.

Multi-enzyme cascade reactions capture the essence of nature's efficiency by increasing the productivity of a process. Here we describe one such three-enzyme cascade for the synthesis of 6-hydroxyhexanoic acid. Whole cells of Escherichia coli co-expressing an alcohol dehydrogenase and a Baeyer-Villiger monooxygenase (CHMO) for internal cofactor regeneration were used without the supply of external NADPH or NADP+. The product inhibition caused by the ε-caprolactone formed by the CHMO was overcome by the use of lipase CAL-B for in situ conversion into 6-hydroxyhexanoic acid. A stirred tank reactor under fed-batch mode was chosen for efficient catalysis. By using this setup, a product titre of >20 g L-1 was achieved in a 500 mL scale with an isolated yield of 81% 6-hydroxyhexanoic acid.

Mapeamento de Estressores no Trabalho de Expedicionários do Programa Antártico Brasileiro (PROANTAR) / Mapping of Stressors in the Work of Expeditionary Brazilian Antarctic Program (PROANTAR)

RESUMO O programa Antártico Brasileiro (PROANTAR) realiza expedições à Antártica, onde militares e civis são expostos a estressores. A presente pesquisa mapeou os estressores ambientais, ocupacionais e interpessoais percebidos por participantes do PROANTAR. Uma amostra de 38 pessoas, separadas em dois grupos, foi avaliada no início e final de uma expedição. Os resultados obtidos por meio de questionários e entrevistas indicaram prevalência de estressores ambientais (60,71%), ocupacionais (23,80%) e interpessoais (15,47%) no início, e de estressores interpessoais (55,97%), ambientais (32,08%) e ocupacionais (11,94%) ao final. Os resultados sugerem que a convivência forçada gera a percepção de estressores interpessoais se sobrepondo aos ambientais. Fenômenos psicológicos deveriam ser considerados no planejamento de futuras expedições, pois estão relacionados à saúde e desempenho das atividades.

ABSTRACT The Brazilian Antarctic Program (PROANTAR) conducts expeditions to Antarctica, where military and civilian are exposed to stressors. The present research mapped the environmental, occupational and interpersonal stressors perceived by PROANTAR participants. A sample of 38 people, separated into two groups, was evaluated at the beginning and end of an expedition. The results obtained through questionnaires and interviews indicated the prevalence of environmental (60.71%), occupational (23.80%) and interpersonal (15.47%) stressors at the beginning, and interpersonal (55.97%), environmental (32.08%) and occupational (11.94%) stressors at the end. The results suggest that the forced coexistence generates the perception of interpersonal stressors overlapping environmental ones. Psychological phenomena should be considered in the planning of future expeditions, as they are related to health and performance of activities.

Produção de L-asparaginase pela levedura Leucosporidium muscorum CRM 1648 isolada de sedimento marinho coletado na Península Antártica / L-asparaginase production by the yeast Leucosporidium muscorum CRM 1648 isolated from marine sediments collected in Antarctic Peninsula

L-asparaginase (L-ASNase) é uma enzima com propriedades interessantes para a indústria médica, farmacêutica e de alimentos, que tem recebido atenção especial, inclusive no Brasil, por fazer parte do protocolo de tratamento de distúrbios linfoproliferativos, como a leucemia linfoblástica aguda (LLA). No mercado desde a década de 1970, as enzimas de origem bacteriana enfrentam algumas limitações por provocarem reações adversas graves em quase 80% dos pacientes em tratamento. Nesse contexto, L-ASNases provenientes de leveduras se destacam como alternativa, por serem mais próximas às congêneres humanas. A Antártica ainda é um ambiente pouco explorado, com grande diversidade de microrganismos com potencial para a produção de moléculas biológicas de interesse industrial. Nesse contexto, 150 leveduras isoladas de amostras de sedimento marinho coletadas na Península Antártica como parte do projeto MICROSFERA (PROANTAR/CNPq) foram avaliadas para a produção de L-ASNase. A triagem resultou em 9 isolados produtores, dos quais 7 pertencem ao gênero Leucosporidium. A linhagem L. muscorum CRM 1648 foi a que produziu mais enzima (540 U.L-1), com maior produtividade (5,6 U.L-1.h-1) e, por isso, foi alvo deste estudo. A análise univariada de fontes de carbono e nitrogênio indicou maior crescimento desse microrganismo e produção de L-ASNase em meio CD com extrato de levedura, prolina e sacarose. Ureia, cloreto de amônio e sulfato de amônio resultaram em baixa ou nenhuma produção da enzima, sugerindo que a metabolização de fontes de nitrogênio por essa linhagem está sob a influência do fenômeno de repressão catabólica pelo nitrogênio (RCN). Dois delineamentos experimentais do tipo fatorial completo resultaram em um aumento de 10 vezes na produção e produtividade da enzima (4582,5 U.L-1 e 63,6 U.L-1.h-1, respectivamente). A análise univariada da concentração inicial de inóculo (X0), pH inicial do meio, temperatura e adição de água do mar mostrou que a melhor condição para a produção foi: pH = 5,5 ou 6,5, cultivo a 15°C com adição de água do mar (25-50% m/v). A variável X0 não foi significativa nas concentrações avaliadas. Cultivos em biorreator (batelada) foram conduzidos em quatro diferentes níveis de oxigênio dissolvido (OD): (1) OD não controlado e abaixo de 20%, (2) OD não controlado e acima de 20%, (3) OD controlado em 80% e (4) OD controlado em 20%. Os resultados mostraram que OD é fator limitante para o crescimento de L. muscorum CRM 1648 e produção de L-ASNase por essa levedura e deve ser mantido acima de 35% para maior produção da enzima.Neste trabalho, a composição do meio e condições de cultivo foram estabelecidas para favorecer a produção de uma nova L-ASNase livre de atividade glutaminásica por levedura adaptada ao frio, abrindo espaço para novos estudos acerca de seu potencial antileucêmico e possível uso como alternativa às enzimas já existentes no mercado no tratamento de LLA

L-asparaginase (L-ASNase) is an enzyme with interesting properties for medical, pharmaceutical and food industry, which has received special consideration, especially in Brazil, for being part of lymphoproliferative disorders treatment, such as acute lymphoblastic leukemia (ALL). Bacterial enzymes are on the market since the 1970s and face some limitations related to theirserious adverse reactions that reach almost 80% of all patients in treatment. In this context, L-ASNases from yeasts are highlighted as important alternative to bacterial enzymes, due to the closerphylogeny to human congeners. Antarctic environment has much to be explored, with a vast diversity of microorganisms with potential to produce biomolecules with industrial interest. A total of 150 yeasts isolated from Antarctic marine sediments as part of MICROSFERA project (PROANTAR/CNPq) were evaluated for L-ASNase production. The screening resulted in 9 producers, 7 species from the genus Leucosporidium. L. muscorum CRM 1648 was the strain that yielded the highest L-ASNase activity (540 U.L-1) and volumetric productivity (5.6 U.L-1.h-1). Carbon and Nitrogen sources were evaluated by a method of one-factor at a time (OFAT). From the gather results, sucrose, yeast extract and proline resulted in a maximal growth and highest enzyme production.The absence or low production of L-ASNase in medium with urea, ammonium chloride and ammonium sulfate suggests the presence of nitrogen catabolic repression (NCR). Carbon and nitrogen concentration were evaluated by full factorial design and yielded about ten times higher enzyme and volumetric productivity (4582.5 U.L-1 and 63.6 U.L-1.h-1, respectively). Initial inoculum concentration (X0), initial pH, temperature and concentration of seawater in the culture were evaluated by OFAT analysis and the best condition for L-ASNase production was: pH = 5.5 or 6.5, at 15 °C with addition of seawater (25-50 wt%). X0 was not considered a significant variable. Bioreactor assays (in batch regime) were performed in four different dissolved oxygen (DO) levels: (1) without DO control (DO remained under 20%), (2) without DO control (DO remained above 20%), (3) DO controlled at 80%, and (4) DO controlled at 20%.The results showed that DO is a key factor for growth of L. muscorum CRM 1648 and production of L-ASNase by this yeast and should be maintained above 35% for higher production of this enzyme.At this work, the medium and culture conditions were established to support the production of a novel glutaminase-free L-ASNase by a cold adapted yeast, opening a new path for further studies regarding its antileukemic potential and possible use as an alternative for ALL treatment

Immobilization of Candida antarctica Lipase B onto organically-modified SBA-15 for efficient production of soybean-based mono and diacylglycerols.

In this study, SBA-15 was modified by a series of silane coupling reagents and later used to immobilize Candida antartica lipase B (CALB). The enzymatic properties of the immobilized CALB samples were studied. In addition, the catalytic performance in glycerolysis of soybean oil for diacylglycerols (DAG) production was also investigated. The highest enzymatic activity up to 6100.00 ±â€¯246.41 U/g was observed from the propyl methacrylate group modified SBA-15 supported CALB. No loss of activity was observed from the propyl methacrylate group modified SBA-15 supported CALB, but a higher-than-initial activity was notably found from 3-aminopropyl group and n-octyl group modified SBA-15 supported CALB after a 4-h incubation in air at 70 °C. 1-isocyanatopropane group modified SBA-15 supported CALB exhibited selectivity for DAG production. DAG content up to 61.90 ±â€¯2.38 wt% and a DAG/MAG ratio at 3.11 ±â€¯0.08 was obtained after a 24-h reaction at 60 °C in a solvent-free system.

Optimization of enzymatic esterification of dihydrocaffeic acid with hexanol in ionic liquid using response surface methodology.

BACKGROUND: Developing an efficient lipophilization reaction system for phenolic derivatives could enhance their applications in food processing. Low solubility of phenolic acids reduces the efficiency of phenolic derivatives in most benign enzyme solvents. The conversion of phenolic acids through esterification alters their solubility and enhances their use as food antioxidant additives as well as their application in cosmetics. RESULTS: This study has shown that lipase-catalyzed esterification of dihydrocaffeic acid with hexanol in ionic liquid (1-butyl-3-methylimidazoliumbis (trifluoromethylsulfonyl) imide) was the best approach for esterification reaction. In order to achieve the maximum yield, the process was optimized by response surface methodology (RSM) based on a five-level and four independent variables such as: dosage of enzyme; hexanol/dihydrocaffeic acid mole ratio; temperature and reaction time. The optimum esterification condition (Y = 84.4%) was predicted to be obtained at temperature of 39.4 °C, time of 77.5 h dosage of enzyme at 41.6% and hexanol/dihydrocaffeic acid mole ratio of 2.1. CONCLUSION: Finally, this study has produced an efficient enzymatic esterification method for the preparation of hexyl dihydrocaffeate in vitro using a lipase in an ionic liquid system. Concentration of hexanol was the most significant (p < 0.05) independent variable that influenced the yield of hexyl dihydrocaffeate. Graphical abstract Synthesis of different Hexyl dihydrocaffeates in ionic liquid.

Gaseous elemental mercury in the marine boundary layer and air-sea flux in the Southern Ocean in austral summer.

Gaseous elemental mercury (GEM) in the marine boundary layer (MBL), and dissolved gaseous mercury (DGM) in surface seawater of the Southern Ocean were measured in the austral summer from December 13, 2014 to February 1, 2015. GEM concentrations in the MBL ranged from 0.4 to 1.9ngm-3 (mean±standard deviation: 0.9±0.2ngm-3), whereas DGM concentrations in surface seawater ranged from 7.0 to 75.9pgL-1 (mean±standard deviation: 23.7±13.2pgL-1). The occasionally observed low GEM in the MBL suggested either the occurrence of atmospheric mercury depletion in summer, or the transport of GEM-depleted air from the Antarctic Plateau. Elevated GEM concentrations in the MBL and DGM concentrations in surface seawater were consistently observed in the ice-covered region of the Ross Sea implying the influence of the sea ice environment. Diminishing sea ice could cause more mercury evasion from the ocean to the air. Using the thin film gas exchange model, the air-sea fluxes of gaseous mercury in non-ice-covered area during the study period were estimated to range from 0.0 to 6.5ngm-2h-1 with a mean value of 1.5±1.8ngm-2h-1, revealing GEM (re-)emission from the East Southern Ocean in summer.

Lipase mediated synthesis of rutin fatty ester: Study of its process parameters and solvent polarity.

Lipophilization of antioxidants is recognized as an effective strategy to enhance solubility and thus effectiveness in lipid based food. In this study, an effort was made to optimize rutin fatty ester synthesis in two different solvent systems to understand the influence of reaction system hydrophobicity on the optimum conditions using immobilised Candida antartica lipase. Under unoptimized conditions, 52.14% and 13.02% conversion was achieved in acetone and tert-butanol solvent systems, respectively. Among all the process parameters, water activity of the system was found to show highest influence on the conversion in each reaction system. In the presence of molecular sieves, the ester production increased to 62.9% in tert-butanol system, unlike acetone system. Under optimal conditions, conversion increased to 60.74% and 65.73% in acetone and tert-butanol system, respectively. This study shows, maintaining optimal water activity is crucial in reaction systems having polar solvents compared to more non-polar solvents.

Accelerated freshening of Antarctic Bottom Water over the last decade in the Southern Indian Ocean.

Southern Ocean abyssal waters, in contact with the atmosphere at their formation sites around Antarctica, not only bring signals of a changing climate with them as they move around the globe but also contribute to that change through heat uptake and sea level rise. A repeat hydrographic line in the Indian sector of the Southern Ocean, occupied three times in the last two decades (1994, 2007, and, most recently, 2016), reveals that Antarctic Bottom Water (AABW) continues to become fresher (0.004 ± 0.001 kg/g decade-1), warmer (0.06° ± 0.01°C decade-1), and less dense (0.011 ± 0.002 kg/m3 decade-1). The most recent observations in the Australian-Antarctic Basin show a particularly striking acceleration in AABW freshening between 2007 and 2016 (0.008 ± 0.001 kg/g decade-1) compared to the 0.002 ± 0.001 kg/g decade-1 seen between 1994 and 2007. Freshening is, in part, responsible for an overall shift of the mean temperature-salinity curve toward lower densities. The marked freshening may be linked to an abrupt iceberg-glacier collision and calving event that occurred in 2010 on the George V/Adélie Land Coast, the main source region of bottom waters for the Australian-Antarctic Basin. Because AABW is a key component of the global overturning circulation, the persistent decrease in bottom water density and the associated increase in steric height that result from continued warming and freshening have important consequences beyond the Southern Indian Ocean.

Comparative studies of immobilized lipase- and acid-catalyzed fatty acid methyl ester synthesis for seed lipid analysis.

Fatty acids are one of the most important nutrients in food. Acid- or base-catalyzed transesterification methods are commonly used for the analysis of fatty acids. However, several drawbacks were reported for these methods, including the isomerization and degradation of fatty acids. Lipase-catalyzed reactions are usually undertaken at mild conditions, preventing such problems. In this study, commercial resin-bound lipase from Candida antartica was tested for possible application in fatty acid methyl ester analysis. Experimental parameters, including temperature, reaction time, and re-cycling were evaluated. The optimized condition was (5-10 mg lipid, 0.5 mL of MeOH, and 50 mg Novozyme 435 in 2 mL toluene, 80°C for 1 h). In optimized condition, the lipase-catalyzed methods yielded similar results with the chemical method. In overall, lipase-catalyzed transesterification can be a useful alternative to acid-catalyzed methods for fatty acid analysis.

Assessing the effectiveness of specially protected areas for conservation of Antarctica's botanical diversity.

Vegetation is sparsely distributed over Antarctica's ice-free ground, and distinct plant communities are present in each of the continent's 15 recently identified Antarctic Conservation Biogeographic Regions (ACBRs). With rapidly increasing human activity in Antarctica, terrestrial plant communities are at risk of damage or destruction by trampling, overland transport, and infrastructure construction and from the impacts of anthropogenically introduced species, as well as uncontrollable pressures such as fur seal (Arctocephalus gazella) activity and climate change. Under the Protocol on Environmental Protection to the Antarctic Treaty, the conservation of plant communities can be enacted and facilitated through the designation of Antarctic Specially Protected Areas (ASPAs). We examined the distribution within the 15 ACBRs of the 33 ASPAs whose explicit purpose includes protecting macroscopic terrestrial flora. We completed the first survey using normalized difference vegetation index (NDVI) satellite remote sensing to provide baseline data on the extent of vegetation cover in all ASPAs designated for plant protection in Antarctica. Large omissions in the protection of Antarctic botanical diversity were found. There was no protection of plant communities in 6 ACBRs, and in another 6, <0.4% of the ACBR area was included in an ASPA that protected vegetation. Protected vegetation cover within the 33 ASPAs totaled 16.1 km(2) for the entire Antarctic continent; over half was within a single protected area. Over 96% of the protected vegetation was contained in 2 ACBRs, which together contributed only 7.8% of the continent's ice-free ground. We conclude that Antarctic botanical diversity is clearly inadequately protected and call for systematic designation of ASPAs protecting plant communities by the Antarctic Treaty Consultative Parties, the members of the governing body of the continent.

Rich bacterial assemblages from Maritime Antarctica (Potter Cove, South Shetlands) reveal several kinds of endemic and undescribed phylotypes.

Bacterial richness in maritime Antarctica has been poorly described to date. Phylogenetic affiliation of seawater free-living microbial assemblages was studied from three locations near the Argentinean Jubany Station during two Antarctic summers. Sixty 16S RNA cloned sequences were phylogenetically affiliated to Alphaproteobacteria (30/60 clones), Gammaproteobacteria(19/60 clones), Betaproteobacteria and Cytophaga-Flavobacteriia-Bacteroides (CFB), which were (2/60) and (3/60) respectively. Furthermore, six out of 60 clones could not be classified. Both, Alphaproteobacteria and Gammaproteobacteria, showed several endemic and previously undescribed sequences. Moreover, the absence of Cyanobacteria sequences in our samples is remarkable. In conclusion, we are reporting a rich sequence assemblage composed of widely divergent isolates among themselves and distant from the most closely related sequences currently deposited in data banks.

Rich bacterial assemblages from Maritime Antarctica (Potter Cove, South Shetlands) reveal several kinds of endemic and undescribed phylotypes / Una rica colección de bacterias marinas antárticas (Caleta Potter, islas Shetlands del Sur) revela diversos filotipos endémicos y previamente no descritos

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Bacterial richness in maritime Antarctica has been poorly described to date. Phylogenetic affiliation of seawater free-living microbial assemblages was studied from three locations near the Argentinean Jubany Station during two Antarctic summers. Sixty 16S RNA cloned sequences were phylogenetically affiliated to Alphaproteobacteria (30/60 clones), Gammaproteobacteria(19/60 clones), Betaproteobacteria and Cytophaga-Flavobacteriia- Bacteroides (CFB), which were (2/60) and (3/60) respectively. Furthermore, six out of 60 clones could not be classified. Both, Alphaproteobacteria and Gammaproteobacteria, showed several endemic and previously undescribed sequences. Moreover, the absence of Cyanobacteria sequences in our samples is remarkable. In conclusion, we are reporting a rich sequence assemblage composed of widely divergent isolates among themselves and distant from the most closely related sequences currently deposited in data banks.