Inhibitory effect of chlorinated guaiacols on methanogenic activity of anaerobic digester sludge

Of four chlorinated guaiacols, tetrachloroguaiacol at 62 M inhibited acetate methanogenesis, the strongest decreasing activity by 50%. 4,5,6-Trichloroguaiacol, 4,5-dichloroguaiacol, and 4-chloroguaiacol showed 50% inhibition at 0.13, 0.32, and 1.50 mM, respectively. Degradation test results of volatile fatty acids (acetic, propionic, and butyric acid) by anaerobic digester sludge (stored 5 weeks) indicated that syntrophic butyrate degraders of this sludge were more sensitive to tetrachloroguaiacol than acetoclastic methanogens and syntrophic propionate degraders.     

Interaction between carbohydrate residues of alpha(1)-acid glycoprotein (orosomucoid) and progesterone. A fluorescence study

Interaction between progesterone and the carbohydrate residues of alpha(1)-acid glycoprotein was followed by fluorescence studies using calcofluor white. The fluorophore interacts with polysaccharides and is commonly used in clinical studies. Binding of progesterone to the protein induces a decrease in the fluorescence intensity of calcofluor white, accompanied by a shift to the short wavelengths of its emission maximum. The dissociation constant of the complex was found equal to 8.62 microM. Interaction between progesterone and free calcofluor in solution induces a low decrease in the fluorescence intensity of the fluorophore without any shift of the emission maximum. These results show that in alpha(1)-acid glycoprotein, the binding site of progesterone is very close to the carbohydrate residues. Fluorescence intensity quenching of free calcofluor in solution with cesium ion gives a bimolecular diffusion constant (k(q)) of 2.23 x 10(9) M(-1) s(-1). This value decreases to 0.19 x 10(9) M(-1) s(-1) when calcofluor white is bound to alpha(1)-acid glycoprotein. Binding of progesterone does not modify the value of k(q) of the cesium. Previous studies have shown that the terminal sialic acid residue is mobile, while the other glycannes are rigid [Albani, J. R.; Sillen, A.; Coddeville, B.; Plancke, Y. D.; Engelborghs, Y. Carbohydr. Res. 1999, 322, 87-94]. Red-edge excitation spectra and Perrin plot experiments performed on sialylated and asialylated alpha(1)-acid glycoprotein show that binding of progesterone to alpha(1)-acid glycoprotein does not modify the local dynamics of the carbohydrate residues of the protein.     

The effect of cold temperature exposure and long-day photoperiod on the termination of the reproductive diapause of newly emerged female Pissodes strobi (Coleoptera: Curculionidae)

Abstract

• 1 There is confusion in the literature concerning a possible reproductive diapause in the adult white pine weevil Pissodes strobi.
• 2 We evaluated the effects of temperature, photoperiod, feeding substrate and mating status on the sexual maturation and oviposition of female white pine weevils.
• 3 Less than 30% of female P. strobi became sexually mature and laid eggs without experiencing dormancy under a temperature regime of 2 °C for 4 weeks.
• 4 Among the females that experienced a cold temperature treatment after emergence, 80% laid eggs after dormancy when exposed to a long‐day (LD 16 : 8 h) photoperiod and 17.6% laid eggs when exposed to a short‐day (LD 8 : 16 h) photoperiod.
• 5 Significantly more eggs were laid by all the females (with and without a cold treatment) when subjected to a long‐day photoperiod compared with a short‐day photoperiod.
• 6 A period of cold temperature followed by exposure to a long‐day photoperiod with warmer temperatures is required to break reproductive diapause and to obtain a good oviposition response in female P. strobi.
• 7 This study reveals the existence of much intraspecific variation in the response of the white pine weevil to temperature and photoperiod with respect to the induction and termination of reproductive diapause.

     

The development of potential screens based on shoot calcium and iron concentrations for the evaluation of tolerance in Egyptian genotypes of white lupin (Lupinus albus L.) to limed soils

European cultivars of white lupin (Lupinus albus L.) grow poorly in limed or calcareous soils. However, Egyptian genotypes are grown successfully in highly calcareous soil and show no stress symptoms. To examine their physiological responses to alkaline soil and develop potential screens for tolerance, three experiments were conducted in limed and non-limed (neutral pH) soil. Measurements included net CO2 uptake, and the partitioning of Fe2+ and Fe3+ and soluble and insoluble Ca in stem and leaf tissue. Intolerant plants showed clear symptoms of stress, whereas stress in the Egyptian genotypes and in L pilosus Murr. (a tolerant species) was less marked. Only the intolerant plants became chlorotic and this contributed to their reduced net CO2 uptake in the limed soil. In contrast, Egyptian genotypes and L pilosus showed no change in net CO2 uptake between the soils. The partitioning of Ca and Fe either resulted from the stress responses, or was itself a stress response. L pilosus and some Egyptian genotypes differed in soluble Ca concentrations compared with the intolerant cultivars, although no significant difference was apparent in the Ca partitioning of the Egyptian genotype Giza 1. In a limed soil, Giza 1 maintained its stem Fe3+ concentration at a level comparable with that of plants grown in non-limed soil, whereas stem [Fe3+] of an intolerant genotype increased. Gizal increased the percentage of plant Fe that was Fe2+ in its leaf tissue under these conditions; that of the intolerant genotype was reduced. The potential tolerance of the Egyptian genotypes through these mechanisms and the possibility of nutritional-based screens are discussed.     

X-ray microanalytical studies of mineral localization in the needles of white pine (Pinus strobus L.)

Eastern white pine (Pinus strobus L.) shoots from mature trees were collected from two sites of contrasting soil pH: the Glendon campus of York University in Toronto, Ontario (pH 6.7 at 40 cm); and Muskoka near Huntsville, Ontario (pH 4.2 at 40 cm). Needles of ages 1-3 years were removed from the shoots, and the percentage of ash and silica was determined for all ages. Other needles were frozen in liquid nitrogen and kept in a cryo-biological storage system before x-ray microanalysis. Percentages of ash and silica were higher in the needles from Muskoka. Ash and silica increased with needle age for trees from the Muskoka site, but less so at the Toronto site. Of the 13 elements (Na, Mg, Al, Si, P, S, Cl, K, Ca, Mn, Fe, Cu and Zn) detected by microanalysis, Mn, Fe, Cu and Zn were detected in small amounts in the epidermis, endodermis and transfusion tissue (the layer of tracheids and parenchyma immediately surrounding the vascular bundles), and K, P, S and Cl were almost ubiquitous in distribution. Sodium was occasionally detected in the transfusion tissue, and magnesium was concentrated in the endodermal cells. The epidermal walls, transfusion tissue and endodermis were major sites of calcium localization. Silicon was concentrated in the extreme tips of the needles in all tissues, but particularly in the transfusion tissue, and more so in the Muskoka samples. Microanalysis revealed a higher Al content in the Muskoka needles, that Al was concentrated in the needle tips and that the transfusion tissues were major sites of accumulation.     

Extraction buffer effects on detection of transient gene expression in white spruce

β-Glucuronidase (GUS) and luciferase (LUC) reporter genes were introduced into white spruce (Picea glauca [Moench] Voss) cultured cells via particle bombardment. Transient expression of these genes was evaluated by extracting the enzymes using 3 buffers. Different buffers resulted in significantly different sensitivities of GUS and LUC detection. In the case of cobombardment, the buffer that gave high levels of expression of one reporter gene did not necessarily result in a better detection of the second reporter gene. This study indicates that appropriate buffers should be used for maximum detection of reporter genes.     

Use of a fluorescence labelled,carbohydrate-binding module from Phanerochaete chrysosporium Cel7D for studying wood cell wall ultrastructure

The -amino group of the carbohydrate-binding module (CBM) from Phanerochaete chrysosporium cellulase Cel7D was covalently labelled with fluorescein isothiocyanate. The fluorescein-labelled CBM was characterised regarding substrate binding, showing specificity only to cellulose and not to mannan and xylan. Conjugation of fluorescein isothiocyanate to CBM did not affect its binding to cellulose. The labelled CBM was successfully used as a probe for detecting cellulose in lignocellulose material such as never dried spruce and birch wood as well as pulp fibres.     

Use of lysozyme for treatment of bacterial contamination in <Emphasis Type="Italic">in vitro</Emphasis> shoot cultures of fruit plants

Summary Use of lysozyme was tested for treatment of bacterial contaminations in in vitro shoot cultures of quince (Cydonia oblonga) ‘BA 29’ and the hybrid (Prunus persica × P. amygdalus) rootstock ‘GF 677’. Shoots which had been contaminated for about 1 yr by Bacillus circulans and Sphingomonas paucimobilis were treated in liquid culture, at pH 4.5, with 9–36 mg ml⁻¹ egg white lysozyme (EWL), and compared to each other and to untreated cultures for their growth, proliferation, and number of bacterial colony-forming units in the tissues. EWL did not negatively affect shoot growth up to 18 mg ml⁻¹; furthermore, the proliferation rates of EWL-treated shoots were sometimes higher than those of controls. In contrast, the concentration of 36 mg ml⁻¹ had some deleterious effect on the regrowth capacity and shoot production of ‘GF 677’ at the first subculture to solid medium after EWL, treatments. EWL had a simple bacteriostatic effect against Sphingomonas paucimobilis; in contrast, it was effective at 18 mg ml⁻¹ in eliminating Bacillus circulans in both ‘BA 29’ and ‘GF 677’ cultures, after optimal treatment duration.     

Exercise and recovery metabolism in the pacific spiny dogfish (<Emphasis Type="Italic">Squalus acanthias</Emphasis>)

We examined the effects of exhaustive exercise and post-exercise recovery on white muscle substrate depletion and metabolite distribution between white muscle and blood plasma in the Pacific spiny dogfish, both in vivo and in an electrically stimulated perfused tail-trunk preparation. Measurements of arterial-venous lactate, total ammonia, -hydroxybutyrate, glucose, and l-alanine concentrations in the perfused tail-trunk assessed white muscle metabolite fluxes. Exhaustive exercise was fuelled primarily by creatine phosphate hydrolysis and glycolysis as indicated by 62, 71, and 85% decreases in ATP, creatine phosphate, and glycogen, respectively. White muscle lactate production during exercise caused a sustained increase (~12 h post-exercise) in plasma lactate load and a short-lived increase (~4 h post-exercise) in plasma metabolic acid load during recovery. Exhaustive exercise and recovery did not affect arterial PO₂, PCO₂, or PNH₃ but the metabolic acidosis caused a decrease in arterial HCO₃^– immediately after exercise and during the first 8 h recovery. During recovery, lactate was retained in the white muscle at higher concentrations than in the plasma despite increased lactate efflux from the muscle. Pyruvate dehydrogenase activity was very low in dogfish white muscle at rest and during recovery (0.53±0.15 nmol g wet tissue^–1 min^–1; n=40) indicating that lactate oxidation is not the major fate of lactate during post-exercise recovery. The lack of change in white muscle free-carnitine and variable changes in short-chain fatty acyl-carnitine suggest that dogfish white muscle does not rely on lipid oxidation to fuel exhaustive exercise or recovery. These findings support the notion that extrahepatic tissues cannot utilize fatty acids as an oxidative fuel. Furthermore, our data strongly suggest that ketone body oxidation is important in fuelling recovery metabolism in dogfish white muscle and at least 20% of the ATP required for recovery could be supplied by uptake and oxidation of -hydroxybutyrate from the plasma.Abbreviations CoA-SH free coenzyme A - CPT-1 carnitine palmitoyltransferase-1 - CrP creatine phosphate - H⁺_m metabolic proton load - Lac lactate load - PDH pyruvate dehydrogenase - PVP polyvinylpyrrolidone - SCFA-carnitine short-chain fatty acyl-carnitine - TAG triacylglycerol - TENS trancutaneous electrical nerve stimulator Communicated by: L.C.-H. Wang     

Using LCA to examine greenhouse gas abatement policy

The site-generic approach currently adopted by the Life Cycle Assessment (LCA) methodology introduces uncertainties into the impact assessment phase of an LCA study. These uncertainties are greatest for localised and short-lived problems but are less significant for long lasting, cumulative environmental effects. Indeed, the reliability of LCA results is high for problems that manifest at a global scale. Nevertheless, even though these results are considered accurate, it is still often unclear as to their relevance in terms of policy development and decision-making. Therefore, this paper demonstrates how LCA can be used to determine the efficacy of policies aimed at reducing a product system’s contribution to global environmental problems. We accomplish this aim by presenting a case study that evaluates the greenhouse gas contributions of each stage in the life cycle of containerboard packaging and the potential impact on emissions of various policy options available to decision makers. Our analysis showed that in general the most useful strategy was to recycle the used packaging. However, our analysis also indicated that when measures are taken to eliminate sources of methane emissions and encourage the use of plantation timber then recycling is no longer beneficial from a greenhouse perspective. This is because the process energy required in the form of gas and electricity is substantially greater for containerboard manufactured from recycled material than it is for virgin fibre.