Carbon and nitrogen limitation increase chitosan antifungal activity in Neurospora crassa and fungal human pathogens

Chitosan permeabilizes plasma membrane and kills sensitive filamentous fungi and yeast. Membrane fluidity and cell energy determine chitosan sensitivity in fungi. A five-fold reduction of both glucose (main carbon (C) source) and nitrogen (N) increased 2-fold Neurospora crassa sensitivity to chitosan. We linked this increase with production of intracellular reactive oxygen species (ROS) and plasma membrane permeabilization. Releasing N. crassa from nutrient limitation reduced chitosan antifungal activity in spite of high ROS intracellular levels. With lactate instead of glucose, C and N limitation increased N. crassa sensitivity to chitosan further (4-fold) than what glucose did. Nutrient limitation also increased sensitivity of filamentous fungi and yeast human pathogens to chitosan. For Fusarium proliferatum, lowering 100-fold C and N content in the growth medium, increased 16-fold chitosan sensitivity. Similar results were found for Candida spp. (including fluconazole resistant strains) and Cryptococcus spp. Severe C and N limitation increased chitosan antifungal activity for all pathogens tested. Chitosan at 100 μg ml-1 was lethal for most fungal human pathogens tested but non-toxic to HEK293 and COS7 mammalian cell lines. Besides, chitosan increased 90% survival of Galleria mellonella larvae infected with C. albicans. These results are of paramount for developing chitosan as antifungal.

Using a non-invasive stable isotope tracer to measure the absorption of water in humans

The development of solutions that prevent dehydration or promote adequate re-hydration play a vital role in preventing fatigue during exercise, however, the methods commonly used to assess the hydration ability of such solutions are invasive and often assess the components of absorption separately. This paper describes using a non-invasive deuterium tracer technique that assesses gastric emptying and intestinal absorption simultaneously to evaluate the uptake of water during rest and exercise. The kinetics of absorption are further examined by mathematical modelling of the data generated. For the rest group, 0.05 g/kg of body weight of deuterium, contained in gelatine capsules, was ingested with ordinary tap water and saliva samples were collected every 5 min for one hour while the subject remained seated. The deuterium was administered as above for the exercise group but sample collection was during one hour of exercise on a treadmill at 55% of the subject's maximum heart rate. The enrichment data for each subject were mathematically modelled and the parameters obtained were compared across groups using an independent samples t-test. Compared with the rest condition, the exercise group showed delayed absorption of water as indicated by significant differences for the modelling parameters t(2), t(1/2), maximum absorption rate and solution absorption amount at t(1). Labelling with a deuterium tracer is a good measure of the relative rate ingested fluids are absorbed by the body. Mathematical modelling of the data generates rates of maximum absorption and allows calculation of the percentage of the solution that is absorbed at any given time during the testing period. Copyright (C) 2004 John Wiley Sons, Ltd.

Anodizing treatments for magnesium alloys and their effecton corrosion resistance in various environments

This paper reviews various aspects of anodizing of magnesium alloys, such as the basics, processes, properties and applications. It systematically summarises the existing fundamental studies and technical developments of anodizing of magnesium alloys, and concludes that new anodizing processes based on electrolytic plasma anodizing that convert the surface of a magnesium alloy into a hard ceramic coating in an electrolytic bath using high energy electric discharges can offer improved wear and corrosion resistance. These new anodized coatings are often claimed to perform better than the traditional ones obtained through older anodizing processes, such as DOW17 or HAE. The new anodizing techniques are chromate free and hence environment friendly. It is expected that more cost-effective, environment-friendly and non-toxic anodizing techniques will be developed and applied to magnesium alloy components in the future.

Impact of diet composition on blood glucose regulation

Abstract Nutritional management of blood glucose levels is a strategic target in the prevention and management of type 2 diabetes mellitus (T2DM). To implement such an approach it is essential to understand the effect of food on glycaemic regulation and on the underlying metabolic derangements. This comprehensive review summarises the results from human dietary interventions exploring the impact of dietary components on blood glucose levels. Included are the major macronutrients; carbohydrate, protein and fat, micronutrient vitamins and minerals, non-nutrient phytochemicals and additional foods including low-calorie sweeteners, vinegar and alcohol. Based on the evidence presented in this review, it is clear that dietary components have significant and clinically relevant effects on blood glucose modulation. An integrated approach that includes reducing excess body weight, increased physical activity along with a dietary regime to regulate blood glucose levels will not only be advantages in T2DM management, but will benefit the health of the population and limit the increasing worldwide incidence of T2DM.

Nutritional management of blood glucose levels

Background and Objectives: Nutritional management of blood glucose levels is a strategic target in the prevention and management of type 2 diabetes mellitus (T2DM), applicable across the population. To implement a successful strategy it is essential to understand the impact of dietary modulation on the postprandial rise in blood glucose concentrations. Methods: Using the highest quality data, a systematic and comprehensive literature review was undertaken. Included in this review were the major macronutrients (carbohydrate, pro-tein, fat), micronutrient vitamins and minerals, non-nutrient phytochemicals and additional foods such as low-calorie sweeteners, vinegar and alcohol. Results: The strongest corroboration of efficacy for improving glucose homeostasis was for insoluble and moderately fermentable cereal-based fiber and mono-unsaturated fatty acids as replacement of saturated fat. Postprandial glycaemia was decreased by intake of viscous soluble fiber and the predominant mechanism of action was considered to be by delaying absorption of co-ingested carbohydrates. There was weaker but substantial evidence that certain phytochemical-rich foods were likely to be effective. This may be associated with the su-ggestion that the gut microbiota plays an important role in me-tabolic regulation, which includes provision of phytochemical and other metabolites. Conclusions: Based on the evidence, it is clear that dietary components have significant and clinically relevant effects on blood glucose modulation. This suggests that employing a dietary regimen to attenuate the postprandial rise in blood glucose levels along with previously identified targets (reducing excess body weight and an increase in physical activity) will benefit the health of the population and limit the increasing worldwide incidence of T2D.

Florida Bay: Water quality status and trends, historic and emerging algal bloom problems

Florida Bay is a unique subtropical estuary that while historically oligotrophic, has been subjected to both natural and anthropogenic stressors, including hurricanes, coastal eutrophication and other impacts. These stressors have resulted in degradation of water quality in the past several decades, most evidenced by reoccurring blooms of the picocyanobacterium Synechococcus spp. Major nutrient inputs consist of freshwater flows to the eastern region from runoff and regulated canal releases, inputs from the Everglades to the central region via Taylor Slough, exchanges with the Gulf of Mexico, which include intermittent Shark River inputs to the western region, stormwater and wastewater from the Florida Keys, and atmospheric deposition. These nutrient inputs have resulted in a transition from strong phosphorus (P) limitation of phytoplankton in the eastern bay to nitrogen (N) limitation in the western bay. Large blooms of Synechococcus were most pronounced in the central bay region, in the area of transition between P and N limitation, in the mid-1990s. Although non-toxic, these blooms, which have continued intermittently through the early 2000s, resulted in significant sea-grass and benthic organism mortalities. A new suite of stressors in 2005, including the passages of Hurricanes Katrina, Rita, and Wilma, additional canal releases, and the initiation of road construction to widen the main roadway leading to the Keys, were correlated with a large Synechococcus bloom in the previously clear, strongly P- limited, northeastern region of the bay. Sustained for 3 years, this bloom was accompanied by a shift from P limitation to N limitation during its course. Nutrient bioassay experiments suggest that this bloom persisted due to the ability of Synechococcus to access organic N and P sources, microbial and geochemical cycling of organic and inorganic nutrients in the water column and between the water column and sediments (both suspended particles and benthos), and decreased grazing by benthic fauna due to their die-off.

The investigation of photocatalysts and iron based materials in the oxidation and adsorption of toxic organic and chromium materials

The presences of heavy metals, organic contaminants and natural toxins in natural water bodies pose a serious threat to the environment and the health of living organisms. Therefore, there is a critical need to identify sustainable and environmentally friendly water treatment processes. In this dissertation, I focus on the fundamental studies of advanced oxidation processes and magnetic nano-materials as promising new technologies for water treatments. Advanced oxidation processes employ reactive oxygen species (ROS) which can lead to the mineralization of a number of pollutants and toxins. The rates of formation, steady-state concentrations, and kinetic parameters of hydroxyl radical and singlet oxygen produced by various TiO2 photocatalysts under UV or visible irradiations were measured using selective chemical probes. Hydroxyl radical is the dominant ROS, and its generation is dependent on experimental conditions. The optimal condition for generation of hydroxyl radical by of TiO2 coated glass microspheres is studied by response surface methodology, and the optimal conditions are applied for the degradation of dimethyl phthalate. Singlet oxygen (1O2) also plays an important role for advanced processes, so the degradation of microcystin-LR by rose bengal, an 1O2 sensitizer was studied. The measured bimolecular reaction rate constant between MC-LR and 1O2 is ∼ 106 M-1 s-1 based on competition kinetics with furfuryl alcohol. The typical adsorbent needs separation after the treatment, while magnetic iron oxides can be easily removed by a magnetic field. Maghemite and humic acid coated magnetite (HA-Fe3O4) were synthesized, characterized and applied for chromium(VI) removal. The adsorption of chromium(VI) by maghemite and HA-Fe3O4 follow a pseudo-second-order kinetic process. The adsorption of chromium(VI) by maghemite is accurately modeled using adsorption isotherms, and solution pH and presence of humic acid influence adsorption. Humic acid coated magnetite can adsorb and reduce chromium(VI) to non-toxic chromium (III), and the reaction is not highly dependent on solution pH. The functional groups associated with humic acid act as ligands lead to the Cr(III) complex via a coupled reduction-complexation mechanism. Extended X-ray absorption fine structure spectroscopy demonstrates the Cr(III) in the Cr-loaded HA-Fe 3O4 materials has six neighboring oxygen atoms in an octahedral geometry with average bond lengths of 1.98 Å.

Dietary Quality and Comorbidities of Adults at Medical Risk for Diabetes

Background and aims: The current study evaluates following a special diet with diet quality and comorbidities (hypertension, hypercholesterolemia, and obesity) in four racial/ethnic groups diagnosed with prediabetes or “at risk for diabetes”. Methods and results: This is a cross-sectional analysis of data from the National Health and Nutrition Examination Surveys (NHANES), 2007- 2008 and 2009-2010. Sample weights were used to achieve a representative sample. Data were available for N = 2666 adults, aged ≥20 years (508 Mexican American, 294, Other Hispanic, 616 Black non-Hispanic, and 1248 White non-Hispanic) who were medically diagnosed with either prediabetes or “at risk for diabetes”. Those reporting following a special diet had greater odds of meeting saturated fat guidelines (

WARMING AND CHRONIC HIGH NUTRIENT MANIPULATIONS YIELD DIFFERING LEGACY EFECTS ON THE SOIL MICROBIAL COMMUNITY AND NUTRIENT POOLS IN THE LOW ARCTIC

Climate warming is predicted to increase summer air temperatures in the Arctic, warming soils and enhancing microbial decomposition of soil organic matter. Given the size of the soil carbon stores in the Arctic, even a fraction of its release as CO2 to the atmosphere could result in a positive feedback to climate warming. Fertilizers have been used in the past to quickly increase soil solution nutrients pools to mimic predicted concentrations under climate warming. However, because it may have inadvertent affects on the soil microbial community, fertilizer-induced patterns in microbial decomposition may be unrealistic. This study aimed to better understand the proposed mechanism of enhanced microbial decomposition under nutrient addition and warming treatments to discern whether warming alone is enough to stimulate enhanced microbial decomposition, or if nutrients in excess (i.e. chronic high nutrient additions) are necessary to yield such a response. I investigated the impacts of 10 years of greenhouse summer warming, chronic low nutrient factorial addition (5 g N and 1g P m-2 year-1, respectively), and chronic high nutrient factorial addition (10 g N and 5g P m-2 year-1, respectively) treatments on a mesic birch hummock tundra ecosystem near Daring Lake, NWT, Canada. Soil microbial nutrient pools, soil solution nutrient pools, and microbial community structure were measured in the upper organic, lower organic, and uppermost mineral soil depth intervals of all treatment plots in Spring 2014. Interestingly, the low nutrient additions did not yield any significant trends, yet the warming treatment increased soil bacterial richness suggesting a legacy effect of warming from the previous summers. Enhanced microbial nutrient uptake occurred only in the high nutrient addition treatments, and did not significantly alter soil carbon at least within the ten year period of this experiment. Together, these results and the absence of significant impacts of the low nutrient and greenhouse warming treatments suggests that nutrient and carbon cycling in these low arctic soils may be resilient against climate warming, at least over the initial decades.

Exposure to toxic Alexandrium minutum activates the detoxifying and antioxidant systems in gills of the oyster Crassostrea gigas

Harmful algal blooms of Alexandrium spp. dinoflagellates regularly occur in French coastal waters contaminating shellfish. Studies have demonstrated that toxic Alexandrium spp. disrupt behavioural and physiological processes in marine filter-feeders, but molecular modifications triggered by phycotoxins are less well understood. This study analyzed the mRNA levels of 7 genes encoding antioxidant/detoxifying enzymes in gills of Pacific oysters (Crassostrea gigas) exposed to a cultured, toxic strain of A. minutum, a producer of paralytic shellfish toxins (PST) or fed Tisochrysis lutea (T. lutea, formerly Isochrysis sp., clone Tahitian (T. iso)), a non-toxic control diet, in four repeated experiments. Transcript levels of sigma-class glutathione S-transferase (GST), glutathione reductase (GR) and ferritin (Fer) were significantly higher in oysters exposed to A. minutum compared to oysters fed T. lutea. The detoxification pathway based upon glutathione (GSH)-conjugation of toxic compounds (phase II) is likely activated, and catalyzed by GST. This system appeared to be activated in gills probably for the detoxification of PST and/or extra-cellular compounds, produced by A. minutum. GST, GR and Fer can also contribute to antioxidant functions to prevent cellular damage from increased reactive oxygen species (ROS) originating either from A. minutum cells directly, from oyster hemocytes during immune response, or from other gill cells as by-products of detoxification.

Alcohol consumption and Mediterranean Diet adherence among health science students in Spain: the DiSA-UMH Study

Objective: To describe the association between consumption of different alcoholic beverages and adherence to the Mediterranean diet. Methods: A cross-sectional analysis was conducted of the baseline data of the DiSA-UMH study, an ongoing cohort study with Spanish health science students (n = 1098) aged 17-35 years. Dietary information was collected by a validated 84-item food frequency questionnaire. Participants were grouped into non-drinkers, exclusive beer and/or wine drinkers and drinkers of all types of alcoholic beverages. Mediterranean diet adherence was determined by using a modification of the relative Mediterranean Diet Score (rMED; score range: 0-16) according to consumption of 8 dietary components. We performed multiple linear and multinomial regression analyses. Results: The mean alcohol consumption was 4.3 g/day (SD: 6.1). A total of 19.5%, 18.9% and 61.6% of the participants were non-drinkers, exclusive beer and/or wine drinkers and drinkers of all types of alcoholic beverages, respectively. Participants who consumed beer and/or wine exclusively had higher rMED scores than non-drinkers (β: 0.76, 95%CI: 0.25-1.27). Drinkers of all types of alcoholic beverages had similar rMED scores to non-drinkers. Non-drinkers consumed less fish and more meat, whereas drinkers of all types of alcoholic beverages consumed fewer fruits, vegetables and more meat than exclusive beer and/or wine drinkers. Conclusions: The overall alcohol consumption among the students in our study was low-to-moderate. Exclusive beer and/or wine drinkers differed regarding the Mediterranean diet pattern from non-drinkers and drinkers of all types of alcohol. These results show the need to properly adjust for diet in studies of the effects of alcohol consumption.

Synthesis, characterization, and application of PHB-based gels for cultural heritage conservation

The aim of my master thesis is developing novel, greener approaches for the cleaning of artworks: such treatment consists in the removal of old varnish layers which tend to discolor or darken with time, thus allowing replacement with a new protecting coat. While protocols presently applied can be effective in the cleaning of the artworks, none of them take into account conservators’ health safety and environmental issues. Thus, using biomass-derived components, which are non-toxic and reusable and/or compostable might bring into the heritage conservation an additional awareness about safety and environmental claiming. The laboratory work for the thesis is a collaborative work between different groups. The biggest part of the work was at the Polymer group where gels were synthesized using Polyhydroxybutyrate (PHB) from sustainable resources and green solvents. The use of the gels might help to reduce the volatilization of solvents and contributes to the localization of the cleaning action. After the preparation of the gels, different characterization methods were used in order to estimate their properties and shelf-life. Finally, the work was completed on the application of the gels on sculpture, coated with undesired layers to be removed. Here, pre-mapping of the areas of interest was realized with different optical techniques, followed by the application of the gels for the cleaning and analyzing the effectiveness of cleaning.

Aquatic Toxicity Of Dyes Before And After Photo-fenton Treatment.

This study evaluated the ecotoxicity of five dyes to freshwater organisms before and during their photo-Fenton degradation. EC50 (48h) of the five tested dyes ranged from of 6.9 to >1000mgL(-1) for Daphnia similis. In the chronic tests IC50 (72h) varied from 65 to >100mgL(-1) for Pseudokirchneriella subcapitata and IC50 (8 days) from 0.5 to 410mgL(-1) for Ceriodaphnia dubia. Toxicity tests revealed that although the applied treatment was effective for decolorization of the dye, the partial mineralization may be responsible for the presence of degradation products which can be either more toxic than the original dye, as is the case of Vat Green 3 and Reactive Black 5, lead to initially toxic products which may be further degraded to non toxic products (acid Orange 7 and Food Red 17), or generate non toxic products as in the case of Food Yellow 3. The results highlighted the importance of assessing both acute and chronic toxicity tests of treated sample before effluent discharge.

Biocompósitos de matriz glioxal-fenol reforçada com celulose microcristalina

Glioxal pode ser obtido a partir de biomassa (como da oxidação de lipídeos) e não é tóxico ou volátil, tendo sido por isso utilizado no presente trabalho como substituto de formaldeído na preparação de resina fenólica do tipo novolaca, sendo usado como catalisador o ácido oxálico, que também pode ser obtido de fontes renováveis. A resina glioxal-fenol foi utilizada na preparação de compósitos reforçados com celulose microcristalina (CM, 30, 50 e 70% em massa), uma celulose com elevada área superficial. As imagens de microscopia eletrônica de varredura (MEV) das superfícies fraturadas demonstraram que os compósitos apresentaram boa interface reforço/matriz, consequência da elevada área superficial da CM e presença de grupos polares (hidroxilas) tanto na matriz como na celulose, o que permitiu a formação de ligações hidrogênio, favorecendo a compatibilidade entre ambas. A análise térmica dinâmico-mecânica (DMTA) demonstrou que todos os compósitos apresentaram elevado módulo de armazenamento à temperatura ambiente. Além disso, o compósito reforçado com 30% de CM apresentou baixa absorção de água, comparável à do termorrígido fenólico, que é utilizado em escala industrial. Os resultados demonstraram que compósitos com boas propriedades podem ser preparados usando elevada proporção de materiais obtidos de biomassa.

Sources of variation of energy and nutrient intake among adolescents in São Paulo, Brazil

The aim of the current study was to describe the sources of variation of energy and nutrient intake and to calculate the number of repetitions of diet measurements to estimate usual intake in adolescents from São Paulo, Brazil. Data was collected using 24-hour dietary recalls (24hR) in 273 adolescents between 2007 and 2008. Individuals completed a repeat 24hR around two months later. The sources of variation were estimated using the random effect model. Variance ratios (within-person to between-person variance ratio) and the number of repetitions of 24hR to estimate usual intake were calculated. The principal source of variation was due to within-person variance. The contribution of day of week and month of year was less than 8%. Variations ranged from 1.15 for calcium to 7.31 for vitamin E. The number of 24hR repeats required to estimate usual intake varied according to nutrient and gender, numbering 15 for males and 8 for females.