Chemical analysis of the product in acid-catalyzed solvolysis of cellulose using polyethylene glycol and ethylene carbonate

Degradation and decomposition of cellulose were studied in an acid-catalyzed solvolysis treatment of biomass using polyethylene glycol (PEG) and ethylene carbonate (EC). The solvolysis reaction was followed by a typical reaction system of wood liquefaction that uses sulfuric acid catalyst at 140° or 150°C at atmospheric pressure. The methods of fractionation and chemical analysis of the degraded cellulose in the solvolyzed product are discussed. The solvolyzed product was separated into several fractions, and they were hydrolyzed to release glucose and levulinic acid to determine the quantity of glucosides and levulinates in the solvolysis product. The data clearly showed that the solvolysis reaction had the same mechanism when using PEG or EC. Degradation of cellulose leads to the formation of glucosides, which then decompose, resulting in a levulinic acid structure, and producing a water-insoluble fraction. The conversion rates of both glucosides and levulinates strongly depend on the reaction conditions of the solvolysis. In particular, EC promotes faster conversion of the reactions. The method discussed here is a chemical analytical technique for characterization of the products of wood liquefaction.     

Preparation of antimicrobial reduced lysozyme compatible in food applications

The structural and antimicrobial functions of lysozyme reduced with food-compatible reducing agents-cysteine (Cys) and glutathione (GSH)-were investigated. The disulfide bonds were partially reduced by thiol-disulfide exchange reactions under heat-induced denaturing conditions from 55 to 90 degrees C. The results showed that treatment of lysozyme with Cys and GSH resulted in the introduction of new half-cystine residues (2-3 residues/mol of protein). The released SH groups, in turn, rendered the lysozyme molecule more flexible, being accompanied by a dramatic increase in the surface hydrophobicity and exposure of tryptophan residues. As a consequence, the resulting reduced lysozymes were more capable of binding to lipopolysaccharides (LPS) and permeabilizing the bacterial outer membrane, as evidenced by the liposome leakage experiment, than were native or heated lysozyme. Both reduced lysozymes displayed significantly higher antimicrobial activity than native or heated lysozyme against Salmonella enteritidis (SE) in sodium phosphate buffer (10 mM, pH 7.2) at 30 degrees C for 1 h. Their minimal inhibitory concentrations (MICs) against the tested bacteria were about 150- and 25-fold lower than their respective MICs of native or heated lysozyme. The results suggest that partially reduced lysozyme could be used as a potential antimicrobial agent for prevention of SE attack.     

Influence of edible fruit coatings on Drosophila suzukii (Matsumura) (Diptera: Drosophilidae) oviposition and development

Drosophila suzukii (Matsumura) is a highly invasive vinegar fly recently detected in the United States that severely threatens the viability of soft skinned fruit production. Insecticides mitigate some of this damage, but alternative methods to manage D. suzukii infestation are needed. We tested three edible coatings to determine if they could prevent or reduce oviposition by D. suzukii females or affect immature survivorship and development in two important host crops, blueberry and raspberry. None of the coatings prevented oviposition, but some reduced the number of eggs laid. Two carnauba wax-based coatings, PrimaFresh 45 and Raynox, dramatically reduced survivorship of immature D. suzukii in raspberries, but not in blueberries. Our results suggest that obtaining thorough, even coverage in the field will be essential if edible coatings are to be used as a management strategy for D. suzukii.     

Taking post‐development theory to the field: Issues in development research,Northern Thailand

Emerging post‐development literatures consider how post‐structural and post‐colonial critiques of development could form the basis for new kinds of development practices. Much of the search for such post‐development possibilities draws on new theories of discourse. This paper considers the challenges of bringing together empirical research and the experience of doing development with the often ethereal and deeply speculative work of discourse theorists. I reflect on the course taken by my own research in Northern Thailand, and discuss the possibilities that can emerge as theory confronts empirics, and conceptual frameworks are transformed through the daily politics of fieldwork.     

Swarming of bats at underground sites in Britain—implications for conservation

We investigated the extent of visitation of underground sites during late summer and autumn (‘swarming’) by bats. Bats were captured at eight cave, mine and tunnel sites in southern England over 6 years (1995-2000). A total of 3077 bats representing 11 of Britain's 16 species was caught. Myotis bats predominated in autumn. At some sites these are rarely seen during winter hibernation counts. Myotis nattereri and M. daubentonii were most common. However, species composition changed seasonally. At one site, M. brandtii dominated early in the season and at all sites peak activity of M. daubentonii was earlier than in M. nattereri. Relatively high numbers of internationally vulnerable species such as M. bechsteinii and Barbastella barbastellus were recorded. There was a strong male bias in captures of swarming species. Swarming probably has an important reproductive function, most males are reproductively active at this time and such sites may be important for outbreeding. Due to this and the large number of individuals and species concerned, the conservation of ‘swarming sites’ is vitally important. Clearly swarming sites merit special consideration in conservation management strategies for cave-dwelling bats.     

Historical change in coastal sage scrub in southern California,USA in relation to fire frequency and air pollution

Invasions resulting in the transformation of one ecosystem to another are an increasingly widespread phenomenon. While it is clear that these conversions, particularly between grassland and shrubland systems, have severe consequences, it is often less clear which factors are associated with these conversions. We resampled plots from the 1930s (Weislander VTMs) to test whether two widely assumed factors, changes in fire frequency and nitrogen deposition, are associated with the conversion of coastal sage scrublands to exotic grasslands in southern California. Over the 76-year period, coastal sage scrub cover declined by 49%, being replaced predominantly by exotic grassland species. Grassland encroachment was positively correlated with increased fire frequency and, in areas with low fire frequencies, air pollution (percent fossil carbon as indicated by ∂¹⁴C, likely correlated with nitrogen deposition). We conclude that increases in fire frequency and air pollution over the last several decades in southern California may have facilitated the conversion of coastal sage shrubland to exotic grassland systems.     

Bio-corrosion: A note on fungal solubilization of iron from stainless steels

Cultures of the fungus Penicillium italicum can extract Fe from powdered stainless steels, including highly corrosion-resistant alloys containing 11 to 13 % Ni. Physical contact of fungus with metal is unnecessary, but acidification alone fails to account for the phenomenon. Evidence from other sources suggests that fungal metabolites are involved.