Impact of a Comprehensive Nutrition and Lifestyle Education Intervention on Body Weight and Health-Related Outcomes in Morbidly-Obese Hispanic-Americans Following Laparoscopic Roux-En Y Gastric Bypass

As morbid obesity increasingly affects Hispanic-Americans, the incidence of Roux-en-Y gastric bypass procedures (RYGB) among this population rises. Prospective research on the impact of postoperative educational interventions focused on Hispanic-Americans is needed to prevent premature weight loss plateau, weight regain, nutritional deficiencies, and relapse of obesity-related comorbidities. This randomized-controlled study evaluated the impact of a comprehensive nutrition and lifestyle education intervention (6 biweekly postoperative sessions that incorporated motivational strategies for behavioral change) as compared to a non-comprehensive approach (printed guidelines for healthy lifestyle). The variables to consider are body weight, obesity-related comorbidities (depression, diabetes, dyslipidemia, and others), nutrient status, physical activity, and eating habits in 144 morbidly-obese adult Hispanic-Americans 6 to 12 months following RYGB. Patients were randomly assigned to either the comprehensive intervention (n=72) or the comparison group (n=72). Participants (mean age 44.5 ± 13.5 years) were mainly Cuban-born females (83.3%). Intervention sessions attendance was 64%. At 12 months, both groups lost weight significantly, but those in the comprehensive intervention experienced greater excess weight loss than those in the comparison group (80% vs. 64% from preoperative excess weight, P\u3c.001). Intervention participants were significantly more involved in physical activity (+ 14 min/week vs. – 4 min/week), had decreased depression, joint illness, and required less medication for comorbidities than comparison participants. Additionally, those in the comprehensive intervention had sustained supplement intake experiencing less folate deficiency (P=.014). The non-comprehensive intervention group significantly decreased their protein and supplement intake compared to the intervention group. Patients in the comprehensive intervention had significantly better eating habits reflected by fewer episodes of dumping syndrome, constipation, and night eating, than those in the comparison group who reported greater eating in response to negative emotions (P=.003). These findings support the importance of a comprehensive educational approach to achieve more effective weight reduction and health-related outcomes to prevent relapse of obesity-related comorbidities and nutritional deficiencies in Hispanic-Americans 6 to 12 months following RYGB

The Origins of Cooperative Bacterial Communities

Bacteria live in complex multispecies communities. Intimately interacting bacterial cells are ubiquitous on biological and mineral surfaces in all habitats. Molecular and cellular biologists have unraveled some key mechanisms that modulate bacterial interactions, but the ecology and evolution of these associations remain poorly understood. One debate has focused on the relative importance of cooperation among cells in bacterial communities. Some researchers suggest that communication and cooperation, both within and among bacterial species, have produced emergent properties that give such groups a selective advantage. Evolutionary biologists have countered that the appearance of group-level traits should be viewed with caution, as natural selection almost invariably favors selfishness. A recent theory by Morris, Lenski, and Zinser, called the Black Queen Hypothesis, gives a new perspective on this debate (J. J. Morris, R. E. Lenski, and E. R. Zinser, mBio 3(2):e00036-12, 2012). These authors present a model that reshapes a decades-old idea: cooperation among species can be automatic and based upon purely selfish traits. Moreover, this hypothesis stands in contrast to the Red Queen Hypothesis, which states that species are in constant evolutionary conflict. Two assumptions serve as the core of the Black Queen model. First, bacterial functions are often leaky, such that cells unavoidably produce resources that benefit others. Second, the receivers of such by-products will tend to delete their own costly pathways for those products, thus building dependency into the interactions. Although not explicitly required in their model, an emergent prediction is that the initiation of such dependency can favor the spread of more obligate coevolved partnerships. This new paradigm suggests that bacteria might often form interdependent cooperative interactions in communities and moreover that bacterial cooperation should leave a clear genomic signature via complementary loss of shared diffusible functions

Distribution of Hydrogen Peroxide In the Northwest Pacific Ocean

[1] Hydrogen peroxide (H2O2) is a reactive oxygen intermediate involved in the cycling of metals and dissolved organic matter. Because little is known of its distribution in the North Pacific Ocean, we determined H2O2 in surface waters continuously and obtained vertical profiles at nine stations during a cruise from Japan to Hawaii. Surface water H2O2 varied from less than 10 to more than 250 nmol dm(-3). A diel cycle in surface water H2O2 (similar to 25 nmol dm(-3)) was observed only on one day during the monthlong cruise. This is contrary to expectations based on the usual assumption of photo-production as the dominant input of H2O2. Experiments were also conducted during the cruise to examine both photo-production and dark decay. The net rate of photo-production at a station near Hawaii was determined to be 8 nmol dm(-3) h(-1), similar to rates reported for the central Atlantic Ocean and Antarctic. However, this maximum estimate of photo-production is also similar to probable rates of H2O2 input by other mechanisms ( biological production and rain). The pseudo-first-order rate constant for dark decay varied from 0.1 to 0.2 d(-1), which is toward the low end of previous reports of H2O2 decay rates, and was observed to increase proportionately to the dissolved organic carbon concentration. Taken together, these results suggest that photo-production of H2O2 in open ocean waters may be less important than previously thought and therefore H2O2 is likely less of an indicator of the photo-chemical reactivity of surface waters than hoped for. Furthermore, we observed that the H2O2 inventory for the upper 200 m of the water column has a maximum at midlatitudes. We suggest that this results from diminished inputs at high latitude as well as increased decay rates at low latitudes

The Black Queen Hypothesis: Evolution of Dependencies through Adaptive Gene Loss

Reductive genomic evolution, driven by genetic drift, is common in endosymbiotic bacteria. Genome reduction is less common in free-living organisms, but it has occurred in the numerically dominant open-ocean bacterioplankton Prochlorococcus and “Candidatus Pelagibacter,” and in these cases the reduction appears to be driven by natural selection rather than drift. Gene loss in free-living organisms may leave them dependent on cooccurring microbes for lost metabolic functions. We present the Black Queen Hypothesis (BQH), a novel theory of reductive evolution that explains how selection leads to such dependencies; its name refers to the queen of spades in the game Hearts, where the usual strategy is to avoid taking this card. Gene loss can provide a selective advantage by conserving an organism’s limiting resources, provided the gene’s function is dispensable. Many vital genetic functions are leaky, thereby unavoidably producing public goods that are available to the entire community. Such leaky functions are thus dispensable for individuals, provided they are not lost entirely from the community. The BQH predicts that the loss of a costly, leaky function is selectively favored at the individual level and will proceed until the production of public goods is just sufficient to support the equilibrium community; at that point, the benefit of any further loss would be offset by the cost. Evolution in accordance with the BQH thus generates “beneficiaries” of reduced genomic content that are dependent on leaky “helpers,” and it may explain the observed nonuniversality of prototrophy, stress resistance, and other cellular functions in the microbial world

Measurement and cycling of hydrogen peroxide in seawater

Hydrogen peroxide is a redox active chemical transient present in the marine photic zone. Its formation and decomposition in seawater we re studied in order to gain an understanding of its role in marine biogeochemical processes. The study of hydrogen peroxide in seawater required a highly sensitive and specific assay. The horseradish peroxidase-scopoletin method, previously used in natural waters, was rigorously tested for the unequivocal determination of nanomolar concentrations of hydrogen peroxide in seawater. Fluorometric detection of the enzymatic oxidation of scopoletin is correlated to the peroxide content of the sample. The lack of substrate specificity of the enzyme made the study of potential artefacts in natural waters critical. Hydrogen peroxide was measured in the presence of low molecular weight organic peroxides, which are known to act as substrates for horseradish peroxidase. A relatively rapid (minutes),simple, and highly sensitive (10 -9 M) field assay was developed for hydrogen peroxide. Optimizing assay parameters and technique allows measurements of detailed profiles of traces of hydrogen peroxide, well below the sea surface. Hydrogen peroxide accumulated in seawater samples exposed to sunlight. Average midday photochemical formation rates of hydrogen peroxide were 3X 10 -7 M hr -l in coastal waters and 2Xl0-B H hr -l in oligotrophic waters. Production rates correlated we]] with the near UV opt I cal absorbance of the samples. Analogous to findings in other natural waters, light absorbing natural organic compounds in seawater were identified as the primary precursors of hydrogen peroxide production. This in situ abiotic photochemical process was found to be the predominant source of hydrogen peroxide in seawater. Contributions from biological processes were negligible, but may be important below the photic zone where photochemistry is not competitive.The major hydrogen peroxide decomposition pathway in seawater follows first order kinetics. Half-lives were found to range from 10 to 120 hours in coastal and oligotrophic surface waters surrounding South Florida, respectively. At oligotrophic stations, lifetimes below the photic zone were on the order of 10 to 40 days. Filtering seawater samples through 0. 2 μm filters increased the lifetimes dramatically. Evidence suggests that hydrogen peroxide decomposition is controlled enzymatically by the particulate fraction in natural seawater. Marine microorganisms, particularly prokaryotes, added to seawater mediated hydrogen peroxide decomposition very efficiently. The results indicate the existence of a delicate balance between abiotic sources and biological sinks of hydrogen peroxide in seawater. Interestingly, turnover is much higher in coastal waters than in oligotrophic waters, maintaining similar steady state concentrations of -7 10 M hydrogen peroxide in both environments

Spatial and temporal variations of hydrogen peroxide in Gulf of Mexico waters

Hydrogen peroxide concentrations in the Gulf of Mexico were measured on two cruises in May and August, 1982, in a variety of locations ranging from oligotrophic oceanic stations to highly productive coastal sites. Measurements were made using a fluorescence decay technique. Depth profiles of H2O2 exhibit surface maxima of 1-2 × 10-7 mol L-1 and decreasing concentrations with depth. Peroxide concentrations decreased only slightly or were invariant with depth in the mixed layer but decreased sharply to below the limit of detection (5 × 10-9 mol L-1) in the region of the pycnocline at the base of the mixed layer. Surface concentrations were generally highest in coastal regions but did not vary by more than a factor of three among all stations studied. There was a marked diel variation in peroxide profiles, with the highest values occurring during the late afternoon, and the lowest values occurring at dawn. Diel variations were more pronounced in coastal surface waters than in oligotrophic waters. The observations are consistent with photochemical formation of H2O2 by photooxidation of dissolved organic matter. However, other formation pathways, such as biological formation or atmospheric deposition, cannot be ruled out at this point. © 1985

Spatial and temporal variations of hydrogen peroxide in Gulf of Mexico waters

Hydrogen peroxide concentrations in the Gulf of Mexico were measured on two cruises in May and August, 1982, in a variety of locations ranging from oligotrophic oceanic stations to highly productive coastal sites. Measurements were made using a fluorescence decay technique. Depth profiles of H2O2 exhibit surface maxima of 1-2 × 10-7 mol L-1 and decreasing concentrations with depth. Peroxide concentrations decreased only slightly or were invariant with depth in the mixed layer but decreased sharply to below the limit of detection (5 × 10-9 mol L-1) in the region of the pycnocline at the base of the mixed layer. Surface concentrations were generally highest in coastal regions but did not vary by more than a factor of three among all stations studied. There was a marked diel variation in peroxide profiles, with the highest values occurring during the late afternoon, and the lowest values occurring at dawn. Diel variations were more pronounced in coastal surface waters than in oligotrophic waters. The observations are consistent with photochemical formation of H2O2 by photooxidation of dissolved organic matter. However, other formation pathways, such as biological formation or atmospheric deposition, cannot be ruled out at this point. © 1985

Estimación de la evapotranspiración de dos cultivares de Gerbera jamesonii en condiciones de hidroponia.

La producción comercial de Gerbera jamesonii para flor de corte ocupa un lugar destacado a nivel mundial. En Argentina la superficie de cultivo bajo invernadero está en aumento y no cubre la demanda del mercado. La introducción de nuevas tecnologías de riego y cultivo que están llevando a cabo los productores, requiere del conocimiento de las necesidades hídricas del cultivo para que el sistema resulte eficiente. El objetivo de este trabajo es caracterizar el consumo hídrico de dos cultivares de Gerbera en hidroponía, mediante el ajuste de modelos de uso corriente, para el área de influencia de la ciudad de Buenos Aires, en el ciclo de primavera. En este ensayo se evalúa el consumo de agua mediante bandejas de drenaje a fin dedeterminar el coeficiente del cultivo (Kc) para cada una de las fórmulas empleadas; también secaracteriza el clima del invernadero a fin de hallar los valores de evapotranspiración potencial o de referencia (Eto) para esa situación empleando fórmulas de uso corriente y se selecciona la relación entre Eto y Kc que determine la evapotranspiración del cultivo (Etc) que mejor se ajuste al consumo medido. No se han detectado diferencias significativas entre ETc y ETo calculada por el método de Penman-Monteith, modificado por FAO, siendo el que mejor se ajusta a la estimación de Eto en las condiciones de invernadero; por el contrario, se han hallado diferencias significativas utilizando el método de Blaney-Criddle. Asimismo, se han detectado diferencias significativas entre la ETc de las dos variedades ensayadas