Autointoxication in residues ofAsparagus officinalis L.

Summary In a greenhouse experiment the growth of asparagus seedlings was retarded by the residue treatments in both vermiculite and sand cultures. In general, the retardation of asparagus root by residues was slightly greater than the retardation of shoot in both cultures. The retardation of the growth of asparagus seedlings by root and stem treatments was usually higher than that by old root litter. Root and stem extracts strongly inhibited the development of asparagus seedlings in the seed bioassay. The inhibition of extracts to the growth of shoot was greater than that to the growth of root. The quantities in the total phenolics and catachol type phenolics from root, stem and old root litter extracts corresponded to the autotoxicity in the seed bioassay. The soil extracts obtained from using acetone, methanol, and XAD-4 extractions strongly inhibited the shoot and root development of asparagus seedlings in the bioassay. The efficiency of phenolics extraction by the XAD-4 method was significantly higher than that by acetone and methanol extractions. The results obtained in the greenhouse experiment and bioassay revealed that phytotoxic substances present in the residues and the soil of asparagus and may be partially responsible for the asparagus replanting problems.     

The role of forest residues in the accounting for the global warming potential of bioenergy

Bioenergy makes up a significant portion of the global primary energy pie, and its production from modernized technology is foreseen to substantially increase. The climate neutrality of biogenic CO₂ emissions from bioenergy grown from sustainably managed biomass resource pools has recently been questioned. The temporary change caused in atmospheric CO₂ concentration from biogenic carbon fluxes was found to be largely dependent on the length of biomass rotation period. In this work, we also show the importance of accounting for the unutilized biomass that is left to decompose in the resource pool and how the characterization factor for the climate impact of biogenic CO₂ emissions changes whether residues are removed for bioenergy or not. With the case of Norwegian Spruce biomass grown in Norway, we found that significantly more biogenic CO₂ emissions should be accounted towards contributing to global warming potential when residues are left in the forest. For a 100‐year time horizon, the global warming potential bio factors suggest that between 44 and 62% of carbon‐flux, neutral biogenic CO₂ emissions at the energy conversion plant should be attributed to causing equivalent climate change potential as fossil‐based CO₂ emissions. For a given forest residue extraction scenario, the same factor should be applied to the combustion of any combination of stem and forest residues. Life cycle analysis practitioners should take these impacts into account and similar region/species specific factors should be developed.     

PONDR-FIT: A meta-predictor of intrinsically disordered amino acids

Protein intrinsic disorder is becoming increasingly recognized in proteomics research. While lacking structure, many regions of disorder have been associated with biological function. There are many different experimental methods for characterizing intrinsically disordered proteins and regions; nevertheless, the prediction of intrinsic disorder from amino acid sequence remains a useful strategy especially for many large-scale proteomic investigations. Here we introduced a consensus artificial neural network (ANN) prediction method, which was developed by combining the outputs of several individual disorder predictors. By eight-fold cross-validation, this meta-predictor, called PONDR-FIT, was found to improve the prediction accuracy over a range of 3 to 20% with an average of 11% compared to the single predictors, depending on the datasets being used. Analysis of the errors shows that the worst accuracy still occurs for short disordered regions with less than ten residues, as well as for the residues close to order/disorder boundaries. Increased understanding of the underlying mechanism by which such meta-predictors give improved predictions will likely promote the further development of protein disorder predictors. Access to PONDR-FIT is available at www.disprot.org.     

Split Renilla Luciferase Protein Fragment-assisted Complementation (SRL-PFAC) to Characterize Hsp90-Cdc37 Complex and Identify Critical Residues in Protein/Protein Interactions

Hsp90 requires cochaperone Cdc37 to load its clients to the Hsp90 superchaperone complex. The purpose of this study was to utilize split Renilla luciferase protein fragment-assisted complementation (SRL-PFAC) bioluminescence to study the full-length human Hsp90-Cdc37 complex and to identity critical residues and their contributions for Hsp90/Cdc37 interaction in living cells. SRL-PFAC showed that full-length human Hsp90/Cdc37 interaction restored dramatically high luciferase activity through Hsp90-Cdc37-assisted complementation of the N and C termini of luciferase (compared with the set of controls). Immunoprecipitation confirmed that the expressed fusion proteins (NRL-Hsp90 and Cdc37-CRL) preserved their ability to interact with each other and also with native Hsp90 or Cdc37. Molecular dynamic simulation revealed several critical residues in the two interaction patches (hydrophobic and polar) at the interface of Hsp90/Cdc37. Mutagenesis confirmed the critical residues for Hsp90-Cdc37 complex formation. SRL-PFAC bioluminescence evaluated the contributions of these critical residues in Hsp90/Cdc37 interaction. The results showed that mutations in Hsp90 (Q133A, F134A, and A121N) and mutations in Cdc37 (M164A, R167A, L205A, and Q208A) reduced the Hsp90/Cdc37 interaction by 70–95% as measured by the resorted luciferase activity through Hsp90-Cdc37-assisted complementation. In comparison, mutations in Hsp90 (E47A and S113A) and a mutation in Cdc37 (A204E) decreased the Hsp90/Cdc37 interaction by 50%. In contrast, mutations of Hsp90 (R46A, S50A, C481A, and C598A) and mutations in Cdc37 (C54S, C57S, and C64S) did not change Hsp90/Cdc37 interactions. The data suggest that single amino acid mutation in the interface of Hsp90/Cdc37 is sufficient to disrupt its interaction, although Hsp90/Cdc37 interactions are through large regions of hydrophobic and polar interactions. These findings provides a rationale to develop inhibitors for disruption of the Hsp90/Cdc37 interaction.     

Fusarium mycotoxins: a review of global implications for animal health, welfare and productivity

Trichothecenes, zearalenone (ZEN) and fumonisins are the major Fusarium mycotoxins occurring on a worldwide basis in cereal grains, animal feeds and forages. Other important Fusarium mycotoxins include moniliformin and fusaric acid. Spontaneous outbreaks of Fusarium mycotoxicoses have been recorded in Europe, Asia, New Zealand and South America and, in addition, chronic exposure occurs on a regular and more widespread scale. The metabolism and adverse effects of the Fusarium mycotoxins are considered in this review with particular reference to recent data on specific and proposed syndromes and to interactions among co-occurring mycotoxins. Within the trichothecene group, deoxynivalenol (DON) is associated with emesis, feed refusal and depressed feed intake in pigs, while T-2 toxin and diacetoxyscirpenol (DAS) are now clearly linked with oral lesions in poultry. The gut microflora of farm livestock are able to transform DON to a de-epoxy derivative. In contrast, the ovine metabolism of ZEN results in the production of five metabolites and relatively high levels of these forms may be excreted in the urine as glucuronides. There is now undisputed evidence that ZEN and its metabolites possess estrogenic activity in pigs, cattle and sheep, but T-2 toxin has also been implicated in reproductive disorders in farm livestock. Fumonisins are positively linked with pulmonary edema in pigs, leukoencephalomalacia in equines and with deranged sphingolipid metabolism in these animals. Fusarium mycotoxins have also been provisionally implicated in ovine ill-thrift, acute mortality of poultry and in duodenitis/proximal jejunitis of horses. Several Fusarium mycotoxins may co-occur in a particular feed ingredient or in compound feedingstuffs. In general, combinations of Fusarium mycotoxins result in additive effects, but synergistic and/or potentiating interactions have been observed and are of greater concern in livestock health and productivity. Synergistic effects have been reported between DON and fusaric acid; DON and fumonisin B₁ (FB₁); and DAS and the Aspergillus-derived aflatoxins. Limited evidence of potentiation between FB₁ and DON or T-2 toxin has also emerged recently. Additive and synergistic effects between known and unidentified mycotoxins may account for enhanced adverse effects observed on feeding Fusarium-contaminated diets. The potential for transmission of DON into eggs and of ZEN into porcine kidney and liver has been demonstrated. However, lactational carry-over of FB₁ appears not to occur, at least in cows and sows. It is concluded that livestock health, welfare and productivity may be severely compromised by consumption of DON, T-2 toxin, DAS, ZEN and fumonisins and by interactions among these mycotoxins. Safety of some animal products may also be at risk. Furthermore, in view of the limited options available for remediation, it is concluded that exploitation of crops resistant to Fusarium infection offers the most viable strategy for reducing mycotoxin contamination of grain and animal feed.     

牙齿残留物反映的闽西新石器时代人类食谱

本项目对福建闽西地区奇和洞与南山两处新石器时代遗址出土古人类牙齿进行了表面残留物提取与鉴定,通过对其中淀粉粒残留物的种类与数量对比,讨论了全新世初期至中期闽西地区古人类对植物资源的利用方式。这些古人类牙齿表面包含四大类形态不同的淀粉粒:1)多面体形;2)圆形或椭圆形;3)圆锥形;4)水滴形。这些淀粉粒分别代表了禾本科植物种子、植物地下根茎部分和疑似的坚果类,这些都是古人类容易获得的野生食物资源,在新石器时代古人类的饮食中占据着重要的地位。     

葡萄糖淀粉酶色氨酸残基及底物结合位点的研究

 本文用N-溴代琥珀酰亚胺(NBS)对葡萄糖淀粉酶进行特异性修饰,当酶分子表面有3个色氨酸残基被修饰后,酶活力完全丧失。用邹氏图解法测得酶活性中心有一个色氨酸残基是必需的。如果在酶液中加入不同的底物再用NBS氧化,用荧光发射和荧光猝灭光谱检测表明,底物对酶分子有不同程度的保护作用。在被测试的三种底物中,这种保护能力依为糊精>淀粉>麦芽糖。     

Simultaneous determination of triclabendazole and its metabolites in bovine and goat tissues by liquid chromatography-tandem mass spectrometry

A sensitive liquid chromatography–tandem mass spectrometry method for the simultaneous determination of triclabendazole, its main metabolites (triclabendazole sulphone and triclabendazole sulphoxide) and a marker residue (ketotriclabendazole) in bovine and goat muscle, liver, and kidney samples is developed and validated. Analyte extraction from samples is effectively performed using liquid–liquid extraction by acetonitrile. Chromatographic separation is performed on a C₁₈ reversed-phase column with gradient elution. The analytes are detected by tandem quadrupole mass spectrometry after positive electrospray ionization by multiple reaction monitoring. The limits of detection for analytes are found to be 0.25–2.5 μg/kg in muscle tissues and 1–10 μg/kg in liver and kidney tissues, respectively. The recoveries of edible bovine and goat tissues range from 84.9% to 109.5% when spiked at different levels with analytes, with relative standard deviations generally below 12.8%.     

Bromine in soils and peats

Summary Determinations were made by an iodometric method and by gas-liquid chromatography (g.l.c.) of inorganic bromide and total bromine in two soils of widely differing organic matter content, and in eight types of peat. The volumetric method is responsive to both bromide and iodide and gave a combined value. The g.l.c. method is halogen specific and gave individual values for bromide and iodide. Inorganic bromide represented only a small fraction (1.1% and 8%) of the total bromine in the soils, and was an even smaller fraction (0–1%) in the peats. The highly organic soil contained 141 μg total Br/g dry wt compared with 14 μg/g in the other soil. Total Br in the peats ranged from 11–116 μg/g. The organic soil contained an appreciable amount of total I (46 μg/g), while the total I content of the peats ranged from 3–18 μg/g. The possibility is considered that during the decomposition of peat added to soil, organic Br is released which might act as a potential source of inorganic bromide available to plants, so contributing to bromide residues in edible crops.