Effects of hydration,lipids, and temperature on the binding of the volatile aroma terpenes by beta-lactoglobulin powders     

Mironov NA  Breus VV  Gorbatchuk VV  Solomonov BN  Haertlé T 《Journal of agricultural and food chemistry》2003,51(9):2665-2673

The binding properties of dry proteins are relatively poorly known. Many proteins are present in emulsions and suspensions and also in dry forms. This is particularly true of dairy proteins, which are often stored and sold in powdered form. In the present work, the binding of three terpenes (alpha-terpinene, gamma-terpinene, and terpinolene), which belong to the basic aroma components, and of decane by powdered beta-lactoglobulin (BLG) was studied at different hydration levels (0.05-0.40 g of H(2)O/g of protein) and temperatures (298 and 309.5 K), in the presence or absence of lipids and small concentrations of ethanol. Vapor sorption isotherms were determined for these systems by a static method of headspace gas chromatographic analysis. A cooperative effect of hydrophobic hydration was observed for the binding of aroma terpenes and decane by the solid BLG. The temperature increase from 298 to 309.5 K reduced the observed hydration threshold of BLG by 0.05-0.08 g of H(2)O/g of protein. Lipids (1.2% w/w) in hydrated BLG gave at least a 2-fold increase in its binding affinity for the hydrocarbons studied, and synergic effects of the hydration and lipid on this affinity were observed.  相似文献   

Comparative Analysis of Glycoside Hydrolases Activities from Phylogenetically Diverse Marine Bacteria of the Genus Arenibacter     

Irina Bakunina  Olga Nedashkovskaya  Larissa Balabanova  Tatyana Zvyagintseva  Valery Rasskasov  Valery Mikhailov 《Marine drugs》2013,11(6):1977-1998

A total of 16 marine strains belonging to the genus Arenibacter, recovered from diverse microbial communities associated with various marine habitats and collected from different locations, were evaluated in degradation of natural polysaccharides and chromogenic glycosides. Most strains were affiliated with five recognized species, and some presented three new species within the genus Arenibacter. No strains contained enzymes depolymerizing polysaccharides, but synthesized a wide spectrum of glycosidases. Highly active β-N-acetylglucosaminidases and α-N-acetylgalactosaminidases were the main glycosidases for all Arenibacter. The genes, encoding two new members of glycoside hydrolyses (GH) families, 20 and 109, were isolated and characterized from the genomes of Arenibacter latericius. Molecular genetic analysis using glycosidase-specific primers shows the absence of GH27 and GH36 genes. A sequence comparison with functionally-characterized GH20 and GH109 enzymes shows that both sequences are closest to the enzymes of chitinolytic bacteria Vibrio furnissii and Cellulomonas fimi of marine and terrestrial origin, as well as human pathogen Elisabethkingia meningoseptica and simbionts Akkermansia muciniphila, gut and non-gut Bacteroides, respectively. These results revealed that the genus Arenibacter is a highly taxonomic diverse group of microorganisms, which can participate in degradation of natural polymers in marine environments depending on their niche and habitat adaptations. They are new prospective candidates for biotechnological applications due to their production of unique glycosidases.  相似文献   

Response of CH<Subscript>4</Subscript> oxidation and methanotrophic diversity to NH<Subscript>4</Subscript><Superscript>+</Superscript> and CH<Subscript>4</Subscript> mixing ratios     

Svetlana Bykova  Pascal Boeckx  Irina Kravchenko  Valery Galchenko  Oswald Van Cleemput 《Biology and Fertility of Soils》2007,43(3):341-348

Methane oxidising activity and community structure of 11, specifically targeted, methanotrophic species have been examined in an arable soil. Soils were sampled from three different field plots, receiving no fertilisation (C), compost (G) and mineral fertiliser (M), respectively. Incubation experiments were carried out with and without pre-incubation at elevated CH₄ mixing ratios (100 ml CH₄ l⁻¹) and with and without ammonium (100 mg N kg⁻¹) pre-incubation. Four months after fertilisation, plots C, G and M did not show significant differences in physicochemical properties and CH₄ oxidising activity. The total number of methanotrophs (determined as the sum the 11 specifically targeted methanotrophs) in the fresh soils was 17.0×10⁶, 13.7×10⁶ and 15.5×10⁶ cells g⁻¹ for treatment C, G and M, respectively. This corresponded to 0.11 to 0.32% of the total bacterial number. The CH₄ oxidising activity increased 10⁵-fold (20–26 mg CH₄ g⁻¹ h⁻¹), the total number of methanotrophs doubled (28–76×10⁶ cells g⁻¹) and the methanotrophic diversity markedly increased in treatments with a pre-incubation at elevated CH₄ concentrations. In all soils and treatments, type II methanotrophs (62–91%) outnumbered type I methanotrophs (9–38%). Methylocystis and Methylosinus species were always most abundant. After pre-incubation with ammonium, CH₄ oxidation was completely inhibited; however, no change in the methanotrophic community structure could be detected.  相似文献   

Experience in digital mapping of soil cover patterns     

N. P. Sorokina  D. N. Kozlov 《Eurasian Soil Science》2009,42(2):182-193

Methodological problems of large-scale soil mapping with the use of digital mapping technologies are discussed. Two variants of obtaining the maps of soil combinations for a test polygon (30 km²) in the area of soddy-podzolic soils with 996 studied soil pits are described. In the first variant, the initial state of soils at studied points was characterized by the taxonomic name of the soil (at the level of soil subtypes); the probability of occurrence of different subtypes within operation cells of the digital map was estimated, and the most probable soil subtypes were assigned to them. This approach was tested for the first time. In the second variant, the initial state of soils at studied points was described with the help of the grades of ecologically meaningful features of soil morphology; the degree of soil gleying and the degree of soil erosion or aggradation were indicated. The integral digital map represented the areas of different agroecological groups of soil combinations. The maps obtained with the help of these two approaches show a satisfactory agreement with the maps of soil cover patterns compiled by traditional methods earlier.  相似文献   

The Synthesis and Fungicidal Activity of 2-Substituted 1-Azol-1-ylmethyl-6-arylidenecyclohexanols     

Sergey V. Popkov  Leonid V. Kovalenko  Mikhail M. Bobylev  Oleg Yu. Molchanov  Miron Z. Krimer  Valery P. Tashchi  Yury G. Putsykin 《Pest management science》1997,49(2):125-129

A number of substituted 2,2-dimethyl-6-arylidene-1-triazol-1-ylmethylcyclohexanols and 2,2-dimethyl-6-arylidene-1-imidazol-1-ylmethylcyclohexanols were prepared from 2-methylcyclohexanone in four steps: Claisen–Schmidt condensation with substituted benzaldehydes, methylation of the resulting 2-methyl-6-benzylidenecyclohexanones, conversion to the oxiranes by interaction with dimethylsulfonium methylide and reaction of the oxiranes with triazole or imidazole. The compounds obtained were tested for antifungal activity against five phytopathogenic fungi of different taxonomic classes. EC₅₀ values were determined for all compounds. Structure–activity relationships are discussed in broad terms. Some of triazolymethyl-substituted cyclohexanols obtained are more active than triadimenol. © 1997 SCI.  相似文献   

How surface topography relates to materials' properties     

Assender H  Bliznyuk V  Porfyrakis K 《Science (New York, N.Y.)》2002,297(5583):973-976

The topography of a surface is known to substantially affect the bulk properties of a material. Despite the often nanoscale nature of the surface undulations, the influence they have may be observed by macroscopic measurements. This review explores many of the areas in which the effect of topography is macroscopically relevant, as well as introducing some recent developments in topographic analysis and control.  相似文献