Efficacy of novel organotin(IV) complexes on non-durable tropical wood against decay fungi

Interest in organotin(IV) compounds is increasing due to their interesting structural features and possession of biological activities. The objective of this study was to determine the efficacy of novel organotin(IV) complexes against Trametes versicolor and Gloeophyllum trabeum decay fungi. Soil block decay test was performed using T. versicolor and G. trabeum for 16 weeks. Ten 19 × 19 × 19 mm³ sized wood cubes of Alstonia scholaris, Macaranga triloba and Hevea brasiliensis were treated with three levels of concentration (0.1, 0.5 and 1 %) of monomethyltin(IV) (MMT) and monophenyltin(IV) (MPT) of monosubstituted organotin(IV) and dimethyltin(IV) (DMT), diphenyltin(IV) (DPT) and dibutyltin(IV) (DBT) of disubstituted organotin(IV) complexes with 2-acetylpyridine-N(4)-cyclohexyl thiosemicarbazone (APCT) ligand and their respective retention uptake was determined. The best protection against decay fungi was provided by dibutyltin(IV) complex followed by diphenyltin(IV), dimethyltin(IV), monophenyltin(IV) and monomethyltin(IV) complexes with mean weight loss ranging from 4 to 5, 5 to 7, 8 to 9, 10 to 11 and 14 to 19 percent, respectively while the weight loss of the untreated wood cubes varied from 51 to 65 %. Wood densities decreased with increased weight loss. Density reduction of monosubstituted organotin(IV) treated wood cubes was higher than disubstituted organotin(IV) treated wood cubes. Soil block test showed that selected organotin(IV) complexes are effective and among all of them dibutyltin(APCT) complex gave the best protection against the tested T. versicolor and G. trabeum decay fungi.     

The efficacy of commercial silicones against blue stain and mould fungi in wood

Scots pine (Pinus sylvestris L.) samples were vacuum pressure impregnated with quaternary ammonium (quat)-silicone micro-emulsion (<40 nm particle size), amino-silicone macro-emulsion (110 nm) and silicone macro-emulsion with alkyl modified side groups (740 nm). Quat-silicone micro-emulsion caused highest cell wall bulking (4.8%) and anti-swelling efficiency (21.8%) in wood when treated with 30% concentration of silicone in the treatment solution. All three formulations made wood hydrophobic which was evident from a capillary (longitudinal, tangential and radial) water uptake test. Amino-silicone macro-emulsion (10% silicone in treatment solution) resulted in strong resistance to blue stain attack with both pre-weathered and not pre-weathered wood samples. Signs of blue staining were more evident on the pre-weathered samples. Treatment with amino-silicone macro-emulsion (10% silicone in treatment solution) resulted in a certain resistance to mould growth on wood surfaces, whereas wood treated with the same concentration of quat-silicone micro-emulsion and alkyl-modified silicone macro-emulsion exhibited comparatively lower resistance.     

Resistance of European and hybrid aspen wood against two brown-rot fungi

The decay resistance of European (Populus tremula L.) and hybrid (P. tremula x tremuloides) aspen wood against brown-rot fungi was investigated after three different treatments, i.e. conventional drying, press drying and heat treatment. For both aspen species, the mass loss after exposure to Gloeophyllum trabeum was higher than after exposure to Coniophora puteana, regardless of the wood treatment. Conventionally and press dried aspen wood had similar mass losses. However, heat treatment appears to be an effective method to improve the decay resistance of aspen wood, reducing the mass loss by about 30% compared with conventional and press drying. As a function of mass loss, wood exposed to G. trabeum had lower moisture content than wood exposed to C. puteana. This is thought to be due to differences in the degradation pattern between the two brown-rot fungi. On the other hand, European aspen appears to be slightly more resistant to decay than hybrid aspen.     

The impact of the postharvest environment on the viability and virulence of decay fungi

Postharvest decay of fruits, vegetables, and grains by fungal pathogens causes significant economic losses. Infected produce presents a potential health risk since some decay fungi produce mycotoxins that are hazardous to human health. Infections are the result of the interplay between host resistance and pathogen virulence. Both of these processes, however, are significantly impacted by environmental factors, such as temperature, UV, oxidative stress, and water activity. In the present review, the impact of various physical postharvest treatments (e.g., heat and UV) on the viability and virulence of postharvest pathogens is reviewed and discussed. Oxidative injury, protein impairment, and cell wall degradation have all been proposed as the mechanisms by which these abiotic stresses reduce fungal viability and pathogenicity. The response of decay fungi to pH and the ability of pathogens to modulate the pH of the host environment also affect pathogenicity. The effects of the manipulation of the postharvest environment by ethylene, natural edible coatings, and controlled atmosphere storage on fungal viability are also discussed. Lastly, avenues of future research are proposed.     

Influence of fungal decay by different basidiomycetes on the structural integrity of Norway spruce wood

The potential influence of diverse decay patterns caused by different brown rot causing basidiomycetes on the structural integrity of wood was investigated. Therefore, decayed Norway spruce (Picea abies Karst.) specimens representing a wide range of mass loss, caused by four different brown-rot fungi and one white-rot fungus, were applied to a high-energy multiple impact (HEMI)-test series. The relationship between the resistance to impact milling (RIM) and the mass loss by fungal decay could be subdivided into three areas: 1. Prior to measurable mass loss, a strength reduction was detectable due to the depolymerisation of wood cell wall components. 2. Between 0 and 25–30% mass loss, RIM decreased with increasing mass loss. 3. Above 30% mass loss, RIM increased again due to gluing effects of the fungal mycelium. The influence of the different brown rot fungi on the structural integrity of the wood differed slightly, but partly significantly.     

The protective effect of caseinomacropeptide against dental erosion using hydroxyapatite as a model system

Tooth loss due to dental erosion, particularly among children, has increased in many countries and has been linked to increased consumption of acidic drinks. A number of compounds, including bioactive peptides, are therefore being assessed for their potential to improve dental health. Caseinomacropeptide (CMP) contains two major fractions, glycosylated (gCMP) and non-glycosylated (aCMP), both possessing bioactive properties. This study aimed to determine the ability of CMP and its individual fractions to protect teeth against acidic erosion. Hydroxyapatite (HA) as the tooth model was pretreated with CMP peptides before exposure to citrate buffers (as the erosive solution) at pH 2.5, 3.5 and 4.5. A reduction in the dissolution of calcium and phosphate from the treated HA compared with untreated HA demonstrated the protective effect of these peptides, and indicated that whole CMP and its fractions have the potential to reduce the erosive effect of acidic drinks by 30–45%.     

天然虾青素对辐射损伤小鼠辅助保护作用

目的:探讨天然虾青素对小鼠辐射损伤的保护作用。方法:将144只小鼠随机分为3个实验组,剂量分别为100、200、600mg/kg·bw,另设一个辐射对照组,每天灌胃1次,连续20d后,各组均以60Co射线进行一次全身照射,并继续给样品。辐照前、辐照后第3d和14d进行外周血细胞计数;辐照后第3d进行骨髓有核细胞计数和骨髓细胞微核实验;辐照后第14d测定血清溶血素。结果:与辐照模型对照组比较,600mg/kg·bw剂量组能增加外周血白细胞计数,增加小鼠血清溶血素含量,200mg/kg·bw和600mg/kg·bw剂量组能增加小鼠骨髓有核细胞数,降低骨髓细胞微核率。结论:天然虾青素对辐射损伤具有一定的保护作用。     

Biodegradation of wood in dual cultures of selected two fungi determined by chopstick method

Wood was more effectively degraded in dual cultures of Pycnoporus coccineus with either Flammulina velutipes, Pleurotus ostreatus or Polyporus arcularius than in their single cultures based on the weight losses of chopsticks. The similar effects were attained in dual cultures of the selected Basidiomycetes and various soil fungi.     

四氢嘧啶对冷冻面团的保护作用研究

目的 探究四氢嘧啶对冷冻面团的保护作用。方法 以添加四氢嘧啶和未添加四氢嘧啶面团为研究对象,置于-20℃冰箱冷冻0、15、30、60 d,探究酵母菌存活率、酵母菌发酵力、面团比容、水分含量、可冻结水含量和面团二级结构随冷冻时间的变化。结果 在冷冻过程中添加四氢嘧啶面团各指标均优于未添加四氢嘧啶面团,且整体变化趋势较平缓。在冷冻环境下,四氢嘧啶与面团中的水及蛋白质之间发生相互作用,从而抑制冰晶对酵母菌及面筋蛋白的伤害,使面团结构更稳定。结论 四氢嘧啶对冷冻面团中酵母菌活性和面筋蛋白同时起到保护作用且性质稳定,可将其作为一种新型抗冻剂用于冷冻面团生产中,同时也为四氢嘧啶潜在的食品领域应用提供理论基础。     

The effect of acetylation on the Janka hardness of pine wood

This paper addressed the effect of chemical modification with acetic anhydride on Janka hardness of pine wood, a less studied mechanical property. It was found that acetylation did not significantly affect the hardness of wood.     

Promising antifungal effect of some Euro-Asiatic plants against dangerous pathogenic and toxinogenic fungi

BACKGROUND: Increasing evidence of fungicide‐resistant toxinogenic and pathogenic fungal species is obvious. Looking for new possibilities of antifungal treatment or sources of antifungal substances is a major problem. Some medicinal plants exert strong antifungal properties and could be conveniently used as a promising alternative source for presently problematic antifungal treatment in many areas with respect to their natural origin. Methanol extracts of 46 medicinal plants from the Eurasian area were used in a screening assay for antifungal activity in this study. The growth inhibitory effect was tested against six significant pathogenic and toxinogenic fungal species: Fusarium oxysporum, F. verticillioides, Penicillium expansum, P. brevicompactum, Aspergillus flavus and A. fumigatus. RESULTS: For 14 plant species, the possibility of using them as natural fungicides was indicated. The extract from Grindelia camporum showed significant activity against all target fungal species. The most sensitive target fungus was the toxinogenic and human pathogenic species A. fumigatus. CONCLUSION: This study has identified 14 extracts of medicinal plants with a potential use as an antifungal treatment in various areas. One of them showed promising efficiency against all selected significant pathogenic and toxinogenic fungal species. Copyright © 2010 Society of Chemical Industry     

The effect of acetylation on the Janka hardness of pine wood

This paper addressed the effect of chemical modification with acetic anhydride on Janka hardness of pine wood, a less studied mechanical property. It was found that acetylation did not significantly affect the hardness of wood.