The chemistry of decayed aspen wood and perspectives on its utilization

Summary The objectives of this research were to investigate the proportion of decayed wood in mature aspen stems, its chemical composition and its potential utility as a fuel or as a substrate for conversion to fine chemicals as part of an integrated utilization scheme. Three sound and ten decayed aspen stems were sampled from a boreal forest site. Stem analysis indicate that on average, 20% of the merchantable stem volume was in advanced decay and that considerable sound wood recovery was possible. Wood specific gravity and chemical composition were determined. The holocellulose content (volumetric basis) in advanced decayed wood was reduced by 67%. Thermal analysis of the wood using a differential scanning calorimeter provided graphical evidence of a different sequence of events occurring during the combustion of decayed wood and a resulting heat content per unit weight that was 40% higher than that of sound aspen wood. A higher degree of enzymatic hydrolysis was attainable with white-rotted aspen wood. Approximately 62% of the theoretical glucose yield was obtained from decayed aspen wood after alkali-peroxide pretreatment followed by a 12 hour hydrolysis using technical grade enzymes. The above information is used to elucidate future opportunities for wood recovery and energy production from decayed wood resources.The authors would like to thank the Ontario Ministry of Natural Resources, Kirkland Lake for their cooperation; and for the technical assistance by Sally Krigstin, John Leigh, Samir Konar, Ganesh Deka and Doug Charles. We would also like to thank Dr. Morris Wayman, University of Toronto, for his advice and inspiration. We are especially grateful to the following persons and companies for supplying us with enzymes and their associated technical literature: Mr. John Bayard of Van Waters & Rogers Ltee, Canada, representing NOVO Industri, Denmark; Mr. Ian Hodge representing the Miles Biotechnology Group, Canada; and Dr. Gunther Eckert, B.A.S.F., Germany for obtaining and forwarding the products and information of Rohm GmbH, Germany. This work has been partially funded by the Edward Johnson Fellowship, University of Toronto     

Comparison of Pioneer and Native Woodland Species Growing on Top of an Engineered Landfill,Hong Kong: Restoration Programme

This study dealt with a restoration project conducted at South‐East New Territories Landfill in Hong Kong, in order to screen suitable tree and shrub species (both native and pioneer species) for revegetation. For engineered landfills, landfill gas migration and leachate contamination to the topsoil are rarely problematic, but the lack of nutrients and moisture and poor physical soil conditions may jeopardize potential woodland establishment. The growth performance of 25 woody plant species subjected to 12 different soil amelioration and seedlings planting methods was compared. The results showed that the general performance (mortality rate, apical height, crown diameter and basal diameter) of pioneer species (notably Acacia species) was much better than that of native species in all blocks of woodland mix and scrub mix. The notch planting method was effective in helping seedling roots to have better contact with soil for water uptake, which subsequently increased the survival rates of seedlings, leading to a better tree coverage. Soil ameliorations (horticultural soil with fertilizer and horse and pig manure) generally increased the seedling survival rate and improved plant growth. Tree coverage on all the plant trial blocks was mainly established by the three Acacia species. A planting distance of 1 m was recommended for woodland establishment, and such dense seedlings planting would achieve a better tree coverage under a shorter period of time (than the distance of 3 m). Difficulties in woodland establishment were discussed, and the strategies for achieving a better tree growth were recommended. Copyright © 2015 John Wiley & Sons, Ltd.     

External quality assurance system for antibiotic resistance in bacteria of animal origin in Europe (ARBAO-II), 2003

Initiated in 2003 by the European Union, ARBAO-II aims to establish a monitoring of antimicrobial susceptibility among the veterinary laboratories in all European countries based on validated methodologies. This includes an external quality control system for the most important bacterial pathogens. In 2003 two trials were performed. The first on Salmonella and Escherichia coli involved 31 laboratories in 18 countries and the second on Staphylococcus and Streptococcus included 22 laboratories in 15 countries. For the E. coli strains, 92.8% of the results complied with the reference MICs, for Salmonella 93.7%, for Streptococcus 80.4% and for Staphylococcus 93.1%. Most problems were observed when testing florfenicol (79.2% correct), gentamicin (84.2%) and amoxicillin + cl (84.9%) in E. coli; streptomycin in Salmonella (62.5%); gentamicin (56.7%), lincomycin (71.4%), clindamycin (75.4%), TMP + sulfonamides (75.7%) and chloramphenicol (78.5%) in Streptococcus; erythromycin (81.5%) and oxacillin (78.2.5%) in Staphylococcus. A few laboratories caused most deviations. However, there was no correlation between good performance for one bacterial group and good performance for other groups. This study showed that most laboratories are capable of performing correct susceptibility testing for E. coli and Salmonella, even though performance of some laboratories can be improved, and that some problems exist for Staphylococcus and Streptococcus. This clearly shows the need for continuous harmonisation of methodologies within the EU.     

Recurrence rate, clinical outcome, and cellular proliferation indices as prognostic indicators after incomplete surgical excision of cutaneous grade II mast cell tumors: 28 dogs (1994-2002)

The objectives of this study were to determine local recurrence rate, clinical outcome, and prognostic value of the number of argyrophylic nucleolar organizer regions (AgNORs), presence of proliferating cell nuclear antigen (PCNA), and number of Ki-67-positive nuclei after incomplete surgical excision of canine cutaneous grade II mast cell tumors (MCTs). This retrospective study included 30 MCTs in 28 dogs. Medical records were examined and follow-up information was obtained from owners and referring veterinarians. Only cases in which excision was incomplete and no anvcillary therapy (other than prednisone) for MCT was given were included. Paraffin-embedded tumor tissues were retrieved for AgNORs, PCNA, and Ki-67 staining. Median follow-up time was 811.5 days. Seven (23.3%) tumors recurred locally. Median time to local recurrence was not reached with a mean of 1,713 days. The estimated proportions of tumors that recurred locally at 1, 2, and 5 years were 17.3, 22.1, and 33.3%, respectively. Eleven (39.3%) dogs developed MCTs at other cutaneous locations. Median progression-free survival was 1,044 days. Median overall survival was 1,426 days. The combination of Ki-67 and PCNA scores was prognostic for local recurrence (P = .03) and development of local recurrence was prognostic for decreased overall survival (P = .04). Results suggest that a minority of incompletely excised MCTs recur. Therefore, ancillary local therapies may not always be necessary. However, local recurrence can negatively affect survival of the affected dogs. Cellular proliferation indices may indicate the likelihood of MCT recurrence after incomplete excision.     

Pigments in avocado tissue and oil

Pigments are important contributors to the appearance and healthful properties of both avocado fruits and the oils extracted from these fruits. This study determined carotenoid and chlorophyll pigment concentrations in the skin and three sections of the flesh (outer dark green, middle pale green, and inner yellow flesh-nearest the seed) and anthocyanin concentrations in the skin of Hass avocado during ripening at 20 degrees C. Pigments were extracted from frozen tissue with acetone and measured using high-performance liquid chromatography. Pigments were also measured in the oil extracted from freeze-dried tissue sections by an accelerated solvent extraction system using hexane. Carotenoids and chlorophylls identified in the skin, flesh, and oil were lutein, alpha-carotene, beta-carotene, neoxanthin, violaxanthin, zeaxanthin, antheraxanthin, chlorophylls a and b, and pheophytins a and b with the highest concentrations of all pigments in the skin. Chlorophyllides a and b were identified in the skin and flesh tissues only. As the fruit ripened and softened, the skin changed from green to purple/black, corresponding to changes in skin hue angle, and a concomitant increase in cyanidin 3-O-glucoside and the loss of chlorophyllide a. In flesh tissue, chroma and lightness values decreased with ripening, with no changes in hue angle. The levels of carotenoids and chlorophylls did not change significantly during ripening. As fruit ripened, the total chlorophyll level in the oil from the flesh sections remained constant but declined in the oil extracted from the skin.     

Antibacterial dihydrobenzopyran and xanthone derivatives from Garcinia cowa stem barks

Two new compounds, garciniacowol (1) and garciniacowone (2) along with 15 known compounds were isolated from the stem barks of Garcinia cowa. Their structures were determined by intensive spectroscopic methods. The structure of 1 was a symmetrical dimeric dihydrobenzopyran derivative, whereas the framework of 2 was a triprenyl caged-xanthone precursor. The antibacterial activities against Escherichia coli TISTR 780, Salmonella typhimurium TISTR 292, Staphylococcus aureus TISTR 1466, and methicillin-resistant S. aureus (MRSA) SK1 of the isolated compounds were also evaluated. Compounds 2 and 9 exhibited good antibacterial activity against MRSA SK1 with the same minimum inhibitory concentration (MIC) value of 2 μg/mL. Moreover, compound 2 also showed good antibacterial activity against S. aureus with an MIC value of 2 μg/mL.     

Neuroprotective activity of galloylated cyanogenic glucosides and hydrolysable tannins isolated from leaves of Phyllagathis rotundifolia

The galloylated cyanogenic glucosides based on prunasin (1-7), gallotannins (8-14), ellagitannins (15-17), ellagic acid derivatives (18, 19) and gallic acid (20) isolated from the leaves of Phyllagathis rotundifolia (Melastomataceae) were investigated for their neuroprotective activity against hydrogen peroxide (H₂O₂)-induced oxidative damage in NG108-15 hybridoma cell line. Among these compounds, the gallotannins and ellagitannins exhibited remarkable neuroprotective activities against oxidative damage in vitro as compared to galloylated cyanogenic glucosides and ellagic acid derivatives in a dose-dependent manner. They could be explored further as potential natural neuroprotectors in various remedies of neurodegenerative diseases.     

Molecular characterization of low pathogenic avian influenza viruses, isolated from food products imported into Singapore

We have completed the genetic characterization of all eight gene segments for four low pathogenic avian influenza (LPAI) viruses. The objective of this study was to detect the presence of novel signatures that may serve as early warning indicators of the conversion of LPAI viruses to high pathogenic avian influenza (HPAI) viruses. This study included three H5N2 and one H5N3 viruses that were isolated from live poultry imported into Singapore as part of the national avian influenza virus (AIV) surveillance program. Based on the molecular criterion of the World Organisation for Animal Health (OIE), sequence analysis with the translated amino acid (aa) sequence of the hemagglutinin (HA) gene revealed the absence of multibasic aa at the HA cleavage site, identifying all four virus isolates as LPAI. Detailed phylogenetic tree analyses using the HA and neuraminidase (NA) genes clustered these isolates in the Eurasian H5 lineage, but away from the HPAI H5 subtypes. This analysis further revealed that the internal genes clustered to different avian and swine subtypes, suggesting that the four isolates may possibly share their ancestry with these different influenza subtypes. Our results suggest that the four LPAI isolates in this study contained mainly avian signatures, and the phylogenetic tree for the internal genes further suggests the potential for reassortment with other different circulating avian subtypes. This is the first comprehensive report on the genetic characterization of LPAI H5N2/3 viruses isolated in South-East Asia.     

大麦感染黄花叶病毒后过氧化物酶、酯酶同工酶的变化

大麦黄花叶病毒(BYMV)是一种多粘菌介体传播的土传病毒,筛选抗病品种及建立简便有效的检测方法是选育工作中急需解决的问题。利用等电聚焦凝胶电泳技术分析同工酶的变化,可为育种学家提供生化分析参考。     

Mercury(II) ion-promoted hydrolysis of some organophosphorus pesticides

The promotion of hydrolysis of some organophosphorus pesticides by mercury(II) ion was studied. The presence of mercuric chloride at 20 mg litre^?1 increased the initial hydrolysis rates of malathion, fenitrothion, fenthion and parathion-methyl in pH 5.5 buffer by two to three orders of magnitude. The hydrolysis was found to be first order with respect to both mercury(II) ion and the pesticide. The main hydrolysis product was 3-methyl-4-nitrophenol for fenitrothion, and 4-nitrophenol for parathion-methyl. It is postulated that the reaction involves the formation of a 1:1 complex and a very slow regeneration of the mercury(II) ion from the reacted complex. Mercury(II) ion had little effect on the organophosphorus pesticide dichlorvos.