898 research outputs found
Effects of Exogenous Yeast and Bacteria on the Microbial Population Dynamics and Outcomes of Olive Fermentations.
In this study, we examined Sicilian-style green olive fermentations upon the addition of Saccharomyces cerevisiae UCDFST 09-448 and/or Pichia kudriazevii UCDFST09-427 or the lactic acid bacteria (LAB) Lactobacillus plantarum AJ11R and Leuconostoc pseudomesenteroides BGM3R. Olives containing S. cerevisiae UCDFST 09-448, a strain able to hydrolyze pectin, but not P. kudriazevii UCDFST 09-427, a nonpectinolytic strain, exhibited excessive tissue damage within 4 weeks. DNA sequencing of fungal internal transcribed spacer (ITS) regions and comparisons to a yeast-specific ITS sequence database remarkably showed that neither S. cerevisiae UCDFST 09-448 nor P. kudriazevii UCDFST 09-427 resulted in significant changes to yeast species diversity. Instead, Candida boidinii constituted the majority (>90%) of the total yeast present, independent of whether S. cerevisiae or P. kudriazevii was added. By comparison, Lactobacillus species were enriched in olives inoculated with potential starter LAB L. plantarum AJ11R and L. pseudomesenteroides BGM3R according to community 16S rRNA gene sequence analysis. The bacterial diversity of those olives was significantly reduced and resembled control fermentations incubated for a longer period of time. Importantly, microbial populations were highly dynamic at the strain level, as indicated by the large variations in AJ11R and BGM3R cell numbers over time and reductions in the numbers of yeast isolates expressing polygalacturonase activity. These findings show the distinct effects of exogenous spoilage and starter microbes on indigenous communities in plant-based food fermentations that result in very different impacts on product quality. IMPORTANCE Food fermentations are subject to tremendous selective pressures resulting in the growth and persistence of a limited number of bacterial and fungal taxa. Although these foods are vulnerable to spoilage by unintended contamination of certain microorganisms, or alternatively, can be improved by the deliberate addition of starter culture microbes that accelerate or beneficially modify product outcomes, the impact of either of those microbial additions on community dynamics within the fermentations is not well understood at strain-specific or global scales. Herein, we show how exogenous spoilage yeast or starter lactic acid bacteria confer very different effects on microbial numbers and diversity in olive fermentations. Introduced microbes have long-lasting consequences and result in changes that are apparent even when levels of those inoculants and their major enzymatic activities decline. This work has direct implications for understanding bacterial and fungal invasions of microbial habitats resulting in pivotal changes to community structure and function
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Do arterial stiffness and wave reflection underlie cardiovascular risk in ethnic minorities?
Increasing evidence indicates that remarkable differences in cardiovascular risk between ethnic groups cannot be fully explained by traditional risk factors such as hypertension, diabetes or dislipidemia measured in midlife. Therefore, the underlying pathophysiology leading to this “excess risk” in ethnic minority groups is still poorly understood, and one way to address this issue is to shift the focus from “risk” to examine target organs, particularly blood vessels and their arterial properties more directly. In fact, structural and functional changes of the vascular system may be identifiable at very early stages of life when traditional factors are not yet developed. Arterial stiffening, measured as aortic pulse wave velocity, and wave reflection parameters, especially augmentation index, seem to be an important pathophysiological mechanism for the development of cardiovascular disease and predict mortality independent of other risk factors. However, data regarding these arterial indices in ethnic minorities are relatively rare and the heterogeneity between populations, techniques and statistical methods make it difficult to fully understand their role
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Factors affecting cellular uptake of anthocyanins: the role of pH, glucose and anthocyanin structure
Anthocyanins have poor bioavailability but factors affecting this remain unclear. Uptake into cells could impact the bioavailability and therefore, understanding factors affecting antho-cyanin uptake is pivotal to improve their bioavailability as well as reveal the mechanism for their uptake. This study aimed to investigate the effect of anthocyanin structure, pH and glucose on the uptake of anthocyanins by Caco-2 cells. Anthocyanin extract from strawberry and red grape at 10 or 20 µM was added to Caco-2 cells. Anthocyanin toxicity to the cells was firstly examined to ensure the same cell viability. The uptake was carried out at pH 7 and 6.5 to evaluate the effect of pH. Glucose of 1mM was used to investigate the effect of glucose. The result shows that anthocyanins toxicity was dependent on the concentration and length of exposure. Anthocyanin uptake was concentration-dependent and affected by their structures in which cyanidin-3-glucoside uptake was higher than pelargonidin-3-glucoside. No metabolites from Caco-2 cell activity were detected. An increased uptake with the decrease in pH was observed which may be linked to the increase in anthocyanins stability and may indicate the role of proton co-transporter. This also suggests that the jejunum would be the favorable section of small intestine for anthocyanin uptake. Reduced anthocyanin uptake in the presence of glucose suggested that facilitative glucose transporter could be involved in the uptake of anthocyanins by Caco-2 cells
The impact of processing and matrix on the antibody level, specificity and avidity raised against the peanut allergen Ara h 1
Diatoms in a sediment core from a flood pulse wetland in Malaysia record strong responses to human impacts and hydro‐climate over the past 150 years
Rapid development and climate change in southeast Asia is placing unprecedented pressures on freshwater ecosystems, but long term records of the ecological consequences are rare. Here we examine one basin of Tasik Chini (Malaysia), a UNESCO?designated flood pulse wetland, where human disturbances (dam installation, iron ore mining, oil palm and rubber cultivation) have escalated since the 1980s. Diatom analysis and organic matter geochemistry (?13Corg and C/N ratios) were applied to a sediment sequence to infer ecological changes in the basin since c. 1900 CE. As the Tasik Chini wetland is a rare ecosystem with an unknown diatom ecology, contemporary diatom habitats (plant surfaces, mud surfaces, rocks, plankton) were sampled from across the lake to help interpret the sedimentary record. Habitat specificity of diatoms was not strongly defined and, although planktonic and benthic groupings were distinctive, there was no difference in assemblages among the benthic habitat surfaces. An increase in the proportion of benthic diatom taxa suggests that a substantial decrease in water level occurred between c. 1938 and 1995 CE, initiated by a decline in rainfall (supported by regional meteorological data), which increased the hydrological isolation of the sub?basin. Changes in the diatom assemblages were most marked after 1995 CE when the Chini dam was installed. After this time both ?13Corg and C/N decreased, suggesting an increase in autochthonous production relative to allochthonous river flood pulse inputs. Oil palm plantations and mining continued to expand after c. 1995 CE and we speculate that inputs of pollutants from these activities may have contributed to the marked ecological change. Together, our work shows that this sub?basin of Tasik Chini has been particularly sensitive to, and impacted by, a combination of human and climatically induced changes due to its hydrologically isolated position
Circulating anthocyanin metabolites mediate vascular benefits of blueberries:insights from randomized controlled trials, metabolomics, and nutrigenomics
Potential health benefits of blueberries may be due to vascular effects of anthocyanins which predominantly circulate in blood as phenolic acid metabolites. We investigated which role blueberry anthocyanins and circulating metabolites play in mediating improvements in vascular function and explore potential mechanisms using metabolomics and nutrigenomics. Purified anthocyanins exerted a dose-dependent improvement of endothelial function in healthy humans, as measured by flow-mediated dilation (FMD). The effects were similar to those of blueberries containing similar amounts of anthocyanins while control drinks containing fiber, minerals, or vitamins had no significant effect. Daily 1-month blueberry consumption increased FMD and lowered 24h-ambulatory-systolic-blood-pressure. Of the 63 anthocyanin plasma metabolites quantified, 14 and 17 correlated with acute and chronic FMD improvements, respectively. Injection of these metabolites improved FMD in mice. Daily blueberry consumption led to differential expression (>1.2-fold) of 608 genes and 3 microRNAs, with Mir-181c showing a 13-fold increase in peripheral blood mononuclear cells. Patterns of 13 metabolites were independent predictors of gene expression changes and pathway enrichment analysis revealed significantly modulated biological processes involved in cell adhesion, migration, immune response, and cell differentiation. Our results identify anthocyanin metabolites as major mediators of vascular bioactivities of blueberries and changes of cellular gene programs
Assessment of the Sensitizing Potential of Processed Peanut Proteins in Brown Norway Rats: Roasting Does Not Enhance Allergenicity
Background: IgE-binding of process-modified foods or proteins is the most common method for examination of how food processing affects allergenicity of food allergens. How processing affects sensitization capacity is generally studied by administration of purified food proteins or food extracts and not allergens present in their natural food matrix. [br/]
Objectives: The aim was to investigate if thermal processing increases sensitization potential of whole peanuts via the oral route. In parallel, the effect of heating on sensitization potential of the major peanut allergen Ara h 1 was assessed via the intraperitoneal route. Methods: Sensitization potential of processed peanut products and Ara h 1 was examined in Brown Norway (BN) rats by oral administration of blanched or oil-roasted peanuts or peanut butter or by intraperitoneal immunization of purified native (N-), heated (H-) or heat glycated (G-) Ara h 1. Levels of specific IgG and IgE were determined by ELISA and IgE functionality was examined by rat basophilic leukemia (RBL) cell assay. [br/]
Results: In rats dosed orally, roasted peanuts induced significant higher levels of specific IgE to NAra h 1 and 2 than blanched peanuts or peanut butter but with the lowest level of RBL degranulation. However, extract from roasted peanuts was found to be a superior elicitor of RBL degranulation. Process-modified Ara h 1 had similar sensitizing capacity as NAra h 1 but specific IgE reacted more readily with process-modified Ara h 1 than with native. [br/]
Conclusions: Peanut products induce functional specific IgE when dosed orally to BN rats. Roasted peanuts do not have a higher sensitizing capacity than blanched peanuts. In spite of this, extract from roasted peanuts is a superior elicitor of RBL cell degranulation irrespectively of the peanut product used for sensitization. The results also suggest that new epitopes are formed or disclosed by heating Ara h 1 without glucose
Defining biodiverse reforestation: Why it matters for climate change mitigation and biodiversity
Mixed species plantings present an attractive alternative to monoculture reforestation through their added benefits to biodiversity. Yet there is ambiguity in the use of the term ‘biodiversity’ in carbon and biodiversity markets, which may create perverse outcomes when designing schemes and projects. Here, we review how the concept of biodiversity is defined and applied in reforestation projects, and restoration more broadly. Improved transparency around the use of the term biodiversity is urgently needed to provide rigour in emerging market mechanisms, which seek to benefit the environment and people. Summary: Reforestation to capture and store atmospheric carbon is increasingly championed as a climate change mitigation policy response. Reforestation plantings have the potential to provide conservation co-benefits when diverse mixtures of native species are planted, and there are growing attempts to monetise biodiversity benefits from carbon reforestation projects, particularly within emerging carbon markets. But what is meant by ‘biodiverse’ across different stakeholders and groups implementing and overseeing these projects and how do these perceptions compare with long-standing scientific definitions? Here, we discuss approaches to, and definitions of, biodiversity in the context of reforestation for carbon sequestration. Our aim is to review how the concept of biodiversity is defined and applied among stakeholders (e.g., governments, carbon certifiers and farmers) and rights holders (i.e., First Nations people) engaging in reforestation, and to identify best-practice methods for restoring biodiversity in these projects. We find that some stakeholders have a vague understanding of diversity across varying levels of biological organisation (genes to ecosystems). While most understand that biodiversity underpins ecosystem functions and services, many stakeholders may not appreciate the difficulties of restoring biodiversity akin to reference ecosystems. Consequently, biodiversity goals are rarely explicit, and project goals may never be achieved because the levels of restored biodiversity are inadequate to support functional ecosystems and desired ecosystem services. We suggest there is significant value in integrating biodiversity objectives into reforestation projects and setting specific restoration goals with transparent reporting outcomes will pave the way for ensuring reforestation projects have meaningful outcomes for biodiversity, and legitimate incentive payments for biodiversity and natural capital accounting
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