Landscape context matters: local habitat and landscape effects on the abundance and patch occupancy of collared lizards in managed grasslands

The distribution and abundance of a species may be simultaneously influenced by both local-scale habitat features and the broader patch and landscape contexts in which these populations occur. Different factors may influence patch occupancy (presence–absence) versus local abundance (number of individuals within patches), and at different scales, and thus ideally both occupancy and abundance should be investigated, especially in studies that seek to understand the consequences of land management on species persistence. Our study evaluated the relative influences of variables associated with the local habitat patch, hillside (patch context), and landscape context on patch occupancy and abundance of the collared lizard (Crotaphytus collaris) within tallgrass prairie managed under different fire and grazing regimes in the northern Flint Hills of Kansas, USA. Using a multi-model information-theoretic approach that accounted for detection bias, we found that collared lizard abundance and occupancy was influenced by factors measured at both the local habitat and landscape scales. At a local scale, collared lizard abundance was greatest on large rock ledges that had lots of crevices, high vegetation complexity, and were located higher up on the hillslope. At the landscape scale, collared lizard abundance and occupancy were both higher in watersheds that were burned frequently (1–2 year intervals). Interestingly, grazing only had a significant effect on occupancy and abundance within less frequently burned (4-year burn interval) watersheds. Our results suggest that, in addition to the obvious habitat needs of this species (availability of suitable rock habitat), land-management practices have the potential to influence collared lizard presence and abundance in the grasslands of the Flint Hills. Thus, mapping the availability of suitable habitat is unlikely to be sufficient for evaluating species distributions and persistence in such cases without consideration of landscape management and disturbance history.     

Sterilization of exopolysaccharides produced by deep-sea bacteria: impact on their stability and degradation

Polysaccharides are highly heat-sensitive macromolecules, so high temperature treatments are greatly destructive and cause considerable damage, such as a great decrease in both viscosity and molecular weight of the polymer. The technical feasibility of the production of exopolysaccharides by deep-sea bacteria Vibrio diabolicus and Alteromonas infernus was previously demonstrated using a bioproduct manufacturing process. The objective of this study was to determine which sterilization method, other than heat sterilization, was the most appropriate for these marine exopolysaccharides and was in accordance with bioprocess engineering requirements. Chemical sterilization using low-temperature ethylene oxide and a mixture of ionized gases (plasmas) was compared to the sterilization methods using gamma and beta radiations. The changes to both the physical and chemical properties of the sterilized exopolysaccharides were analyzed. The use of ethylene oxide can be recommended for the sterilization of polysaccharides as a weak effect on both rheological and structural properties was observed. This low-temperature gas sterilizing process is very efficient, giving a good Sterility Assurance Level (SAL), and is also well suited to large-scale compound manufacturing in the pharmaceutical industry.     

Acute effects of chlorogenic Acid on nitric oxide status, endothelial function, and blood pressure in healthy volunteers: a randomized trial

There is mounting evidence that specific dietary polyphenols can enhance vascular health by augmenting nitric oxide. Our aim was to investigate the acute effects of chlorogenic acid, an important dietary phenolic acid present in coffee (400 mg, equivalent to 2 cups of coffee), on nitric oxide status, endothelial function, and blood pressure. Healthy men and women (n = 23) were recruited to a randomized, double-blind, placebo-controlled, crossover trial. Chlorogenic acid resulted in significantly higher plasma concentrations of chlorogenic acid (P < 0.001). Relative to control, the mean post-treatment systolic blood pressure (-2.41 mmHg, 95% CI: -0.03, -4.78; P = 0.05) and diastolic blood pressure (-1.53 mmHg, 95% CI: -0.05, -3.01; P = 0.04) were significantly lower with chlorogenic acid. Markers of nitric oxide status (P > 0.10) and the measure of endothelial function (P = 0.60) were not significantly influenced. Chlorogenic acid can lower blood pressure acutely, an effect that, if sustained, would benefit cardiovascular health.     

Variability of hydrolysis of β-, αs1-, and αs2-caseins by 10 strains of Streptococcus thermophilus and resulting bioactive peptides

Milk proteins contain numerous potential bioactive peptides, which may be released by digestive proteases or by the proteolytic system of lactic acid bacteria during food processing. The capacity of Streptococcus thermophilus to generate peptides, especially bioactive peptides, from bovine caseins was investigated. Strains expressing various levels of the cell envelope proteinase, PrtS, were incubated with α(s1)-, α(s2)-, or β-casein. Analysis of the supernatants by LC-ESI-MS/MS showed that the β-casein was preferentially hydrolyzed, followed by α(s2)-casein and then α(s1)-casein. Numbers and types of peptides released were strain-dependent. Hydrolysis appeared to be linked with the accessibility of different casein regions by protease. Analysis of bonds hydrolyzed in the region 1-23 of α(s1)-casein suggests that PrtS is at least in part responsible for the peptide production. Finally, among the generated peptides, 13 peptides from β-casein, 5 from α(s2)-casein, and 2 from α(s1)-casein have been reported as bioactive, 15 of them being angiotensin-converting enzyme inhibitors.     

Process,structure and texture of extruded whole wheat

Whole wheat is well known by consumers as a health-providing ingredient. Nevertheless, in extruded products it leads to textures that are less favorable to consumer preference compared to its refined flour. An understanding of the effect of extrusion on whole wheat properties is therefore necessary to improve its texture. Whole wheat flour was extruded under varying conditions of water content (18 or 22%), screw speed (400 or 800 rpm) and barrel temperature (140 or 180 °C) and its physicochemical properties were measured. Changing the extrusion conditions significantly modified the volumetric expansion index (between 9.1 and 20.6) and longitudinal expansion (between 0.93 and 2.98) of the samples. Interestingly, changing the extrusion conditions did not significantly modify the sectional expansion. Increasing barrel temperature, water content or screw speed decreased the shear viscosity of the melt. This can be explained by plasticizing effects and modification of starch properties. The change in shear viscosity at the die can mostly explain the effect of process conditions on volumetric expansion of the extruded whole wheat. The stress at rupture of the extruded samples was varied between 0.49 and 1.86 MPa depending on process conditions. It was the lowest at high water content and low screw speed.     

Chemical Composition and Anti-inflammatory Properties of the Unsaponifiable Fraction from Awara (Astrocaryum vulgare M.) Pulp Oil in Activated J774 Macrophages and in a Mice Model of Endotoxic Shock

Awara (Astrocaryum vulgare M.) pulp oil has been shown to possess anti-inflammatory properties in vivo, and contains an unsaponifiable matter rich in bioactive compounds. This study focused on the ethanolic unsaponifiable fraction (EUF) of awara pulp oil. Its chemical composition has been characterized: carotenoid, phytosterol, and tocopherol contents represent 125.7, 152.6, and 6.8?μg/mg of EUF, respectively. We further evaluated this fraction for anti-inflammatory properties in J774 macrophages activated by lipopolysaccharide (LPS) plus interferon (IFN) γ to understand the biological effects of awara pulp oil. EUF strongly decreased nitric oxide (NO), prostaglandin E₂, tumour necrosis factor (TNF) α, and interleukin (IL) -6 and -10 production in activated J774 cells. Moreover, it inhibited expression of inducible NO synthase and cyclooxygenases-2 in vitro. The anti-inflammatory properties of EUF were also confirmed in vivo by modulation of TNFα, IL-6 and IL-10 serum concentration in an endotoxic shock model. Pre-treatment with awara oil fraction offers promise as a protective means to lower the production of excessive amounts of pro-inflammatory molecules.     

Assessment of PCR-based tools for the specific identification of some temperate Meloidogyne species including M. chitwoodi,M. fallax and M. minor

Several conventional PCR tests have been developed for the identification of the European quarantine root-knot nematodes Meloidogyne chitwoodi and M. fallax but data are lacking for the evaluation of their performance in terms of sensitivity, repeatability, reproducibility and specificity against a large range of populations. This study evaluated the performance criteria of three conventional PCR tests recommended by the consensus diagnostic protocol for Meloidogyne chitwoodi and Meloidogyne fallax published by the European and Mediterranean Plant Protection Organization (EPPO): a species-specific PCR (IGS target), a SCAR PCR, and a rDNA ITS PCR-RFLP. Evaluation was carried out with DNA extracts from juveniles, males and females according to EPPO recommendations for test validation. A minimum of 34 populations of target and non target nematode species were tested to check the specificity of these three PCR assays. The three PCR tests were ranked according to their specificity (with regard to cross reaction with other nematodes species or genus) and their sensitivity (detection of a single juvenile or mixed with other species). The species-specific PCR proved to be more sensitive but less specific than the SCAR PCR. The PCR-RFLP enables the identification of several Meloidogyne species but profile analysis can be difficult when several species are present in the mixture. Specific PCR products and RFLP profiles were also observed for M. arenaria and M. enterolobii, and described for M. minor and M. artiellia.