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31.
Arabinofuranosidases act synergistically with other enzymes to depolymerize arabinoxylans by cleaving arabinofuranose substituents from the β‐(1→4)‐linked d ‐xylopyranose backbone. Because arabinose feruloylation is a barrier to some, but not all, arabinofuranosidases, we investigated the actions of three α‐l ‐arabinofuranosidases from the glycoside hydrolase (GH) family 51 on feruloylated arabinoxylan‐oligosaccharide standard compounds with and without feruloyl esterase. GH51 α‐l ‐arabinofuranosidases from Clostridium thermocellum and Cellvibrio japonicus both partially released feruloylated arabinose (up to 59% for C. thermocellum). Simultaneous incubation with arabinofuranosidases and feruloyl esterase quantitatively released arabinose from feruloylated standard compounds. Therefore, although feruloylation does not completely obstruct GH51 arabinofuranosidases, synergistic approaches utilizing multiple enzymes remain the most effective tactic for enzymatic breakdown of feruloylated compounds. 相似文献
32.
Tauber E Zordan M Sandrelli F Pegoraro M Osterwalder N Breda C Daga A Selmin A Monger K Benna C Rosato E Kyriacou CP Costa R 《Science (New York, N.Y.)》2007,316(5833):1895-1898
Circadian and other natural clock-like endogenous rhythms may have evolved to anticipate regular temporal changes in the environment. We report that a mutation in the circadian clock gene timeless in Drosophila melanogaster has arisen and spread by natural selection relatively recently in Europe. We found that, when introduced into different genetic backgrounds, natural and artificial alleles of the timeless gene affect the incidence of diapause in response to changes in light and temperature. The natural mutant allele alters an important life history trait that may enhance the fly's adaptation to seasonal conditions. 相似文献
33.
Dario Di Giuseppe Massimiliano Melchiorre Umberto Tessari Barbara Faccini 《Journal of Soils and Sediments》2016,16(3):909-915
Purpose
An analytical database containing XRF chemical analyses and real density measurements of unconsolidated sediments of the Padania Plain (Northern Italy) has been used to understand the relationship that exists between the soil particle density (ρs) and their bulk chemical composition.Materials and methods
Using a linear regression, we built an equation able to link the particle density with the soil elemental composition.Results and discussion
Positive correlations were found between ρs and SiO2, MgO, CaO and Na2O and negative correlations with K2O, TiO2, Al2O3, Fe2O3 and LOI, reflecting the presence in the soils of quartz and feldspars/mineral clays respectively.Conclusions
Our equation is very useful because it helps to know the density properties of a soil when it is not possible to measure ρs with a pycnometer. On the other hand, by knowing the ρs, it is possible to have a quite precise knowledge about the chemistry of the studied soils.34.
The inhibition or delay of starch digestion by dietary compounds could help manage postprandial blood glucose levels. The objective of this study was to identify constituents from whole grain blue wheat capable of decreasing α‐amylase‐catalyzed starch digestion. An activity‐guided fractionation approach based on liquid chromatography was used to identify solvent‐ and alkaline‐extractable blue wheat constituents reducing α‐amylase‐mediated starch digestion in vitro. Fatty acids, potentially released from cell wall polymers by alkaline hydrolysis, inhibited the digestion of amylose, probably through the formation of amylose‐lipid complexes. However, the degradation of amylopectin was not affected by fatty acids. In addition, 1‐(3,5‐dihydroxyphenyl)heneicosan‐2‐one, a 5‐(2′‐oxoalkyl)resorcinol, was found to reduce starch digestion. However, because the digestion of both amylopectin and amylose was reduced, the inhibition mechanism was different from that of fatty acids. Further research is needed to evaluate whether this component also reduces starch digestion in vivo. Other phenolic compounds of blue wheat such as anthocyanins or hydroxycinnamates were not identified as major starch digestion inhibitors by using the activity‐guided fractionation approach. 相似文献
35.
Sansone Umberto Belli Maria Fernandez José A. Comans Rob N. J. Jeran Zvonka Cavolo Fabio Barbizzi Sabrina De Zorzi Paolo Jacimovic Radojko 《Water, air, and soil pollution》2002,141(1-4):313-324
Aquarium experiments were performed to quantify the inorganic fraction of suspended particles deposited on the external surface of aquatic biota. The mass of suspended particles retained on the surfaces of microalgae growing on submerged substrates and the algal biomass were determined by comparing the scandium content of suspended material with that in algal communities. Scandium, a predominantly soil-associated trace element, has been used as a ‘tracer’ for the inorganic component of suspended particles, because this element is geologically ubiquitous in soils, and it is recognized that it cannot cross natural membranes of plants and other organisms. The algal biomass determined using the scandium content was compared with biomass values calculated using phytopigments as estimates of periphyton biomass. The results indicate that the suspended particle mass adhering to the external periphyton surface may accounted for up to 55% of the total mass collected on submerged artificial substrates. 相似文献
36.
Decline of European beech (Fagus sylvatica) in Sicily and Calabria (Italy) was observed to be associated with the ascomycete Biscogniauxia nummularia. This fungus is naturally present in beech stands and to date has not been considered a primary pathogenic agent. Artificial inoculations were performed to assess its pathogenicity on beech and to determine if Sicilian and Calabrian isolates differ in virulence. Biscogniauxia nummularia played an evident primary pathogenic role under the environmental conditions studied. Virulence of the isolates was variable and did not depend neither on the geographic origin nor the environmental conditions at the sites where pathogenicity testing was performed. 相似文献
37.
Sialic acid in lipopolysaccharides (LPS) of mucosal pathogens is known to be an important virulence factor. Few strains of Helicobacter pylori express sialyl-Lewis-X and we have reported that human and canine Helicobacter bizzozeronii strains express sialyl-lactoseamine in their LPS. However, the role of sialyation of Helicobacter LPS in the interaction with the host cells is still unknown. In this study H. bizzozeronii LPS is shown to activate the TLR2 in a dose and strain dependent manner in the in vitro HEK-293 cells model expressing TLR2, but not the cells expressing TLR4. These results indicate that TLR2 is the specific receptor for H. bizzozzeronii LPS, as previously described for H. pylori. To further explore the role of sialylation of H. bizzozeronii LPS on TLR2 response, H. bizzozeronii Δhbs2 mutant strains deficient in sialyltransferase activity were constructed by homologous recombination. LPS from H. bizzozeronii Δhbs2 strains enhanced the NF-ĸB induction via TLR2 compared to the respective wild types, leading to the conclusion that the sialylation of H. bizzozeronii LPS in wild-type strains may modulate host immune response.
Electronic supplementary material
The online version of this article (doi:10.1186/s13567-014-0133-4) contains supplementary material, which is available to authorized users. 相似文献38.
Castritius S Geier M Jochims G Stahl U Harms D 《Journal of agricultural and food chemistry》2012,60(25):6341-6348
A new approach for the determination of the attenuation limit of beer samples using the specific fingerprint region of middle-infrared (MIR) spectroscopy in combination with multiple regression by partial least-squares (PLS) was developed using an attenuated total reflectance (ATR) module. A specific spectral region between 1200 and 800 cm(-1) was identified as highly informative for the quantification of the limit of attenuation. The absorptions in this region are induced by vibrational bands of ethanol (1080, 1040, and 880 cm(-1)) and dissolved extract, in majority maltotriose (1160-1140 and 1040-980 cm(-1)). The multivariate calibration results in a root mean squared error of calibration (RMSEC) of 0.40% and a validation procedure with independent samples results in a root mean squared error of validation (RMSEV) of 0.50%. A repeatability test, concerning the precision of the developed MIR method as well as the reference method, was analyzed using Student's t test. The test has shown no significant difference between the two random samples. 相似文献
39.
Speranza L Pesce M Patruno A Franceschelli S de Lutiis MA Grilli A Felaco M 《Marine drugs》2012,10(4):890-899
It has been suggested that oxidative stress activates various intracellular signaling pathways leading to secretion of a variety of pro-inflammatory cytokines and chemokines. SHP-1 is a protein tyrosine phosphatase (PTP) which acts as a negative regulator of immune cytokine signaling. However, intracellular hydrogen peroxide (H(2)O(2)), generated endogenously upon stimulation and exogenously from environmental oxidants, has been known to be involved in the process of intracellular signaling through inhibiting various PTPs, including SHP-1. In this study, we investigated the potential role of astaxanthin, an antioxidant marine carotenoid, in re-establishing SHP-1 negative regulation on pro-inflammatory cytokines secretion in U-937 cell line stimulated with oxidative stimulus. ELISA measurement suggested that ASTA treatment (10 μM) reduced pro-inflammatory cytokines secretion (IL-1β, IL-6 and TNF-α) induced through H(2)O(2), (100 μM). Furthermore, this property is elicited by restoration of basal SHP-1 protein expression level and reduced NF-κB (p65) nuclear expression, as showed by western blotting experiments. 相似文献
40.
Dalia Aiello Vladimiro Guarnaccia Alessandro Vitale Gabriella Cirvilleri Giovanni Granata Filomena Epifani Giancarlo Perrone Giancarlo Polizzi Johannes Z. Groenewald Pedro W. Crous 《European journal of plant pathology / European Foundation for Plant Pathology》2014,138(2):347-359
During surveys conducted in 2010–2013, a complete breakage or bending of the trunk and a dry basal stem rot were observed on containerised Brahea armata, B. edulis, Howea forsteriana and Trachycarpus princeps plants in different nurseries located in eastern Sicily (southern Italy). A cylindrocarpon-like species was consistently obtained from diseased palm tissues, while known pathogens of these hosts such as Ganoderma, Phytophthora and Thielaviopsis were not found associated with symptomatic tissues or isolated on standard or selective media. A total of 40 cylindrocarpon-like isolates were collected and characterised based on morphology and DNA phylogeny. Multigene analyses based on the β-tubulin, histone H3, translation elongation factor 1-α, and the internal transcribed spacers (ITS1, 5.8S, ITS2) genes facilitated the identification of a new species, described here as Ilyonectria palmarum. The pathogenicity of one representative isolate collected from each palm species was tested on plants cultivated under nursery conditions and in a growth chamber. All isolates were pathogenic to B. armata, B. edulis, H. forsteriana, and T. princeps and symptoms identical to that observed in nurseries were reproduced. Dry basal stem rot and stem bending caused by Ilyonectria palmarum represents a potentially serious problem for nurseries cultivating containerised palms. 相似文献