Silver uptake byAgaricus bisporus from an artificially enriched substrate

The champignon mushroomAgaricus bisporus was cultivated on compost (wheat and rye straw, hens' manure, gypsum, urea and peat) artificially fortified with silver nitrate added at four different concentrations (0.01, 0.1, 1.0 and 10.3 mg/kg) and 0 mg/kg (control) on a dry weight basis. The method of measurement was flame atomic absorption spectrophotometry after dry ashing of the samples at 420° C and dissolving the residue in 1M nitric acid. The highest concentration of silver, reaching between 120±30–150±36 mg/kg on a dry weight basis, was observed in fruit bodies grown on the most contaminated substrate containing 10.3 mg added Ag/kg dry weight. The silver concentration in caps/stalks/whole fruit bodies ofA. bisporus was positively correlated (r=0.72; P<0.001) with an increasing level of fortification of the substrate. The bioconcentration factor (BCF) of silver in caps/stalks/whole fruit bodies ofA. bisporus was inversely correlated (–0.44bisporus.

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Silberaufnahme von Champignons (Agaricus bisporus) aus künstlich angereichertem Substrat

Zusammenfassung Champignons (Agaricus bisporus) wurden auf Kompost (Weizen- und Roggenstroh, Hühnerdung, Gips, Harnstoff und Torf) gezüchtet, welcher künstlich mit Silbernitrat in vier verschiedenen Mengen-0 (Kontrolle), 0,01, 0,1, 1,0 und 10,3 mg/kg-Trockenmasse angereichert wurde. Als Meßmethode wurde die Flammen AAS verwendet nach dem trockenen Veraschen der Proben bei 420 °C und Auflösen des Rückstandes in 1 M Salpetersäure.Die größte Silberkonzentration von 12±4–14±3 mg/kg Feuchtmasse und 120±30–150±36 mg/kg Trockenmasse wurde in den Fruchtkörpern festgestellt, die auf einem 10,3 mg Ag/kg Trockenmasse enthaltendem Substrat gewachsen sind. Die Silberkonzentration in allen Teilen des Fruchtkörpers hat positiv (r=0,72; p<0,001) mit steigendem Niveau der Substratanreicherung korreliert. Der Biokonzentrationskoeffizient (BCF) von Silber in den Pilzhüten, Strünken und ganzen Fruchtkörpern zeigte eine negative Korrelation (–0,44     

Heavy metal bioaccumulation by cultivated Agaricus bisporus from artificially enriched substrates

 Cultivated Agaricus bisporus possess the ability to bioaccumulate seven heavy metals (Pb, Cd, Hg, Fe, Cu, Mn, and Zn). The cultivated champignon mushroom A. bisporus was grown in soil composts of 16 different compositions. An edible mushroom, A. bisporus was also cultivated on humic compost artificially fortified with the seven heavy metals at five different concentrations (0.1 mg/kg, 0.5 mg/kg, 1.0 mg/kg, 3.0 mg/kg, and 10.0 mg/kg) and on control substrate (0 mg/kg) on a dry weight basis. The method of measuring bioaccumulation was flame atomic absorption spectrophotometry. Received: 1 October 1997 / Revised version: 19 January 1998     

Heavy metal bioaccumulation by cultivated Agaricus bisporus from artificially enriched substrates

Cultivated Agaricus bisporus possess the ability to bioaccumulate seven heavy metals (Pb, Cd, Hg, Fe, Cu, Mn, and Zn). The cultivated champignon mushroom A. bisporus was grown in soil composts of 16 different compositions. An edible mushroom, A. bisporus was also cultivated on humic compost artificially fortified with the seven heavy metals at five different concentrations (0.1 mg/kg, 0.5 mg/kg, 1.0 mg/kg, 3.0 mg/kg, and 10.0 mg/kg) and on control substrate (0 mg/kg) on a dry weight basis. The method of measuring bioaccumulation was flame atomic absorption spectrophotometry.     

Evaluation of harvested mushrooms and viability of Agaricus bisporus growth using casing materials made from spent mushroom substrate

The present work evaluates of harvested mushroom and viability of Agaricus bisporus growth in several casing materials based on spent mushroom substrate. The experiment consisted of eight casing layer, which six were made with spent mushroom substrate. The results confirm the usefulness of reincorporating the spent substrate in new cultivation cycles as an ingredient of casing mixtures. In general, biological efficiency was high, three of the SMS based‐casings surpassing the threshold value of 100 kg 100 kg^?1 of compost. The high electrical conductivity of mixtures containing a large proportion of spent substrate limits the extent to which it can be used, although mixing it with other materials (such as peat) reduces these values to acceptable levels. In short, it makes economic and environmental sense to reuse spent mushroom substrate as an ingredient of alternative casing materials.     

Temporal variations and controlling factors of nitrogen export from an artificially drained coastal forest

Nitrogen losses in drainage water from coastal forest plantations can constrain the long term sustainability of the system and could negatively affect adjacent nutrient sensitive coastal waters. Based on long-term (21 years) field measurements of hydrology and water quality, we investigated the temporal variations and controlling factors of nitrate and dissolved organic nitrogen (DON) export from an artificially drained coastal forest over various time scales (interannual, seasonal, and storm events). According to results of stepwise multiple linear regression analyses, the observed large interannual variations of nitrate flux and concentration from the drained forest were significantly (p < 0.004) controlled by annual mean water table depth, and annual drainage or precipitation. Annual precipitation and drainage were found to be dominant factors controlling variations of annual DON fluxes. Temporal trends of annual mean DON concentration could not be explained explicitly by climate or hydrologic factors. No significant difference was observed between nitrogen (both nitrate and DON) export during growing and nongrowing seasons. Nitrate exhibited distinguished export patterns during six selected storm events. Peak nitrate concentrations during storm events were significantly (p < 0.003) related to 30-day antecedent precipitation index and the minimum water table depth during individual events. The temporal variations of DON export within storm events did not follow a clear trend and its peak concentration during the storm events was found to be significantly (p < 0.006) controlled by the short-term drying and rewetting cycles.     

双孢蘑菇中核酸提取的研究

通过对酶解法、热回流法、超声波和微波法提取双孢蘑菇中核酸效果进行了比较,结果表明微波法优于其它方法。最终,确立采用微波破壁提取双孢蘑菇中核酸。经单因素(时间、功率、NaCl%、pH)实验和正交实验,得最佳提取条件为:30min、300W、4%NaCl、pH为11。用定磷法测得双孢蘑菇核酸提取率为2.78%。     

Bactericidal effects of negative air ions on airborne and surface Salmonella enteritidis from an artificially generated aerosol

The bactericidal effect of high levels of negative ions was studied using a custom-built electrostatic space charge device. To investigate whether the ion-enriched air exerted a bactericidal effect, an aerosol containing Salmonella Enteritidis (SE) was pumped into a sealed plastic chamber. Plates of XLT4 agar were attached to the walls, top, and bottom of the chamber and exposed to the aerosol for 3 h with and without the ionizer treatment. The plates were then removed from the chamber, incubated at 37 degrees C for 24 h, and colonies were counted. An average of greater than 10(3) CFU/plate were observed on plates exposed to the aerosol without the ionizer treatment (control) compared with an average of less than 53 CFU/plate on the ionizer-treated plates. In another series of experiments, the SE aerosol was pumped for 3 h into an empty chamber containing only the ionizer and allowed to collect on the internal surfaces. The inside surfaces of the chamber were then rinsed with 100 ml phosphate-buffered saline that was then plated onto XLT4 plates. While the rinse from the control chamber contained colony counts greater than 400 CFU/ml of wash, no colonies were found in the rinse from the ionizer-treatment chamber. These results indicate that high levels of negative air ions can have a significant impact on the airborne microbial load, and that most of this effect is through direct killing of the organisms. This technology, which also causes significant reduction in airborne dust, has already been successfully applied for poultry hatching cabinets and caged layer rooms. Other potential applications include any enclosed space such as food processing areas, medical institutions, the workplace, and the home, where reduction of airborne and surface pathogens is desired.     

超声波复合酶法提取双孢菇多糖的研究

采用超声波辅助复合酶提法提取双孢菇粗多糖。实验中利用单因素实验探索并确定了超声波的最佳提取时间和料液比分别为30min,1:20。对于复合酶的反应条件,采取L9(34)正交试验确定纤维素酶和中性蛋白酶的最佳工艺条件分别为:纤维素酶加酶量480u/g,pH4.0,酶解温度50℃,酶解时间100min;中性蛋白酶的加酶量100u/g,pH7.5,酶解温度45℃,酶解时间100min。实验中采用超声波辅助破壁方法,提高了纤维素酶的破壁效率,提高了双孢菇多糖的提取率。     

双孢菇水提物抗疲劳作用研究

目的:探讨双孢菇水提物对小鼠的抗疲劳效果。方法:将新鲜双孢菇烘干、粉碎、过筛得双孢菇干粉,按一定比例水浴提取,过滤后滤液为受试样品。受试样品分别以高、中、低三个剂量给小鼠灌胃,对照组灌胃蒸馏水,连续灌胃15d后,小鼠负重5%体重的铅皮,在温度为(30±1)℃的水箱中游泳造成疲劳。拨眼球取血,并取内脏,进行血乳酸、血清尿素氮和肝糖原含量的测定。结果:双孢菇水提物能延长小鼠负重游泳时间,降低小鼠运动后血清尿素氮和血乳酸水平,提高肝糖原的储备量。结论:双孢菇水提物具有明显的抗疲劳功效。     

Dry fermented sausages enriched with lycopene from tomato peel

Tomato industries yield a high amount of by-products mainly tomato peel and seeds. Since tomato peel is rich in lycopene, the direct addition of peel to food products could be a way to use this by-product to obtain a new products enriched in lycopene. This work describes experiments performed to develop dry fermented sausages (salchichón) containing this carotene. 0%, 0.6%, 0.9% and 1.2% (w/w) of dry tomato peel was added to the meat mixture used in sausage manufacture. A slight losts of lycopene was detected after 21 days ripening, however, levels remained between 0.26 and 0.58 mg of lycopene/100 g of sausage. The sensory and textural properties and overall acceptability of all sausages were good, indicating that tomato peel could be added to dry fermented sausages to produce a meat product enriched in lycopene.     

Temperature dependence for anammox bacteria enriched from freshwater sediments

The anoxic ammonium oxidation (anammox) process has been regarded as an attractive alternative process to treat wastewater containing high ammonium concentrations. By the implementation of anammox process at moderately low temperatures (<25°C), the anammox process will be applied to more various industrial wastewater treatments. In this study, we established enrichment cultures of anammox bacteria from freshwater sediments by using an up-flow column reactor equipped with porous polyester nonwoven fabric at moderately low temperatures. Their nitrogen conversion rates reached 0.07-0.26kg-N/m(3)/d. Phylogenetic analysis based on 16S rRNA gene from enrichment cultures revealed the presence of various anammox bacteria affiliated with unknown anammox bacteria as well as known anammox candidates, i.e., Candidatus Kuenenia stuttgartiensis and Candidatus Brocadia fulgida, Candidatus Scalindua wagneri. Anammox bacterial populations were influenced by enrichment conditions, i.e., seed sediments and temperature.     

双孢菇废弃菇柄核酸超声提取工艺优化

为了提高核酸得率,增加双孢菇废弃菇柄的经济价值。本文以双孢菇废弃菇柄为原料,通过单因素试验研究了超声功率、超声工作/间歇时间、超声时间、液固比对核酸提取的影响,并采用响应面法对核酸超声提取工艺进行优化。结果表明,在单因素试验结果基础上,再采用响应面分析法对主要工艺参数进行优化,得到双孢菇废弃菇柄中核酸提取最优工艺参数为:超声功率580 W,液固比34∶1 m L/g,超声时间15 min,理论核酸得率3.49 g/100 g。通过验证试验,实际核酸得率可达3.43 g/100 g,实验证明模型拟合程度良好,误差较小。与传统工艺相比,超声波提取核酸不仅快速高效,且反应过程无物料损失和无副反应发生,是一种安全、经济和简便的提取方法。     

Importance of an N-terminal extension in ribonuclease HII from Bacillus stearothermophilus for substrate binding

The gene encoding ribonuclease HII from Bacillus stearothermophilus was cloned and expressed in Escherichia coli. The overproduced protein, Bst-RNase HII, was purified and biochemically characterized. Bst-RNase HII, which consists of 259 amino acid residues, showed the highest amino acid sequence identity (50.2%) to Bacillus subtilis RNase HII. Like B. subtilis RNase HII, it exhibited Mn2+-dependent RNase H activity. It was, however, more thermostable than B. subtilis RNase HII. When the Bst-RNase HII amino acid sequence is compared with that of Thermococcus kodakaraensis RNase HII, to which it shows 29.8% identity, 30 residues are observed to be truncated from the C-terminus and there is an extension of 71 residues at the N-terminus. The C-terminal truncation results in the loss of the alpha9 helix, which is rich in basic amino acid residues and is therefore important for substrate binding. A truncated protein, Delta59-Bst-RNase HII, in which most of the N-terminal extension was removed, completely lost its RNase H activity. Surface plasmon resonance analysis indicated that this truncated protein did not bind to the substrate. These results suggest that the N-terminal extension of Bst-RNase HII is important for substrate binding. Because B. subtilis RNase HII has an N-terminal extension of the same length and these extensions contain a region in which basic amino acid residues are clustered, the Bacillus enzymes may represent a novel type of RNase H which possesses a substrate-binding domain at the N-terminus.     

Silver content of wild-grown mushrooms from Northern Poland

Wild-grown and mostly edible species of higher mushrooms collected in 1989–1992 from the districts of Gdansk, Elblag and Pia (northern part of Poland) have been investigated with regard to their silver content. In total, 527 samples including 25 mushroom species of six families (Agaricaceae, Boletaceae, Cantharellaceae, Hygrophoraceae, Coprinaceae andRussulaceae) were examined. Among the fungi examined onlyAgaricus campestris andA. augustus were heavy bioaccumulating species and showed the highest concentrations of 35 mg Ag/kg dry weight (1.1–150) and 2.0–6.9 mg/kg, respectively. Silver concentrations exceeding 1.0 mg/kg dry weight were noted inBoletus aestivalis, Lepista nuda, L. personata, and in some specimens ofB. edulis, Leccinum scrabum, L. vulpinum, Cantharellus cibarius andCoprinus comatus.

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Silbergehalt in wildwachsenden Pilzen Nordpolens

Zusammenfassung Der Silbergehalt in wildwachsenden und vorwiegend eßbaren, auf dem Gebiet der Woiwodschaften Gdask, Elblag und Pia (Nordpolen) in den Jahren 1889–1992 gesammelten Pilzsorten wurde untersucht. Im ganzen wurden 527 Proben von 25 Arten der 6 Familien (Agaricaceae, Boletaceae, Cantharellaceae, Hygrophoraceae, Coprinaceae, Russuulaceae) zugehörenden Pilzen untersucht. Von diesen Pilzen waren nurAgaricus campestris undA. augustus stark bioanreichernde Arten mit höchsten Konzentrationen von 35 mg Ag/kg Trockenmasse (1.5–150) und 2.0–6.9 mg/kg. Eine Silberkonzentration von über 1.0 mg/kg Trockenmasse wurde inBoletus aestivalis, Lepista nuda, L. personata und in einigen Exemplaren vonB. edulis, Leccinum scrabum, L. vulpinum, Cantharellus cibarius undCoprinus comatus feststellt.

     

Distribution of aflatoxin M1 in cheese obtained from milk artificially contaminated

Small-scale manufacture of cheese using artificially AFM1 contaminated milk as raw material to study the distribution of such toxin both in whey and in cheese, was carried out. Whole milk with undetectable levels of AFM1 was used. The toxin was added in concentration that varied from 1.7 to 2.0 microg/l of milk. After the home-made production of cheese, the concentration of AFM1 was determined both in whey and in cheese, using the enzymatic immunoassay technique. The greatest proportion, 60%, was detected in whey while 40% AFM1 remained in cheese.     

Characterizing dissolved Cu and Cd uptake in terms of the biotic ligand and biodynamics using enriched stable isotopes

The biotic ligand model considers the biological and geochemical complexities that affect metal exposure. It relates toxicity to the fraction of physiological active sites impacted by reactive metal species. The biodynamic model is a complementary construct that predicts bioaccumulation and assumes that toxicity occurs when influx rates exceed rates of loss and detoxification. In this paper we presume that metal influx rates are mechanistically the resulting processes that characterize transmembrane transport. We use enriched stable isotopes to characterize, both in terms of the biotic ligand and biodynamics, dissolved metal uptake by a freshwater snail at water hardness varying up to 180-fold. Upon 24 h exposure, metal uptake was linear over a range encompassing most environmental concentrations; although saturation kinetics were observed at higher concentrations. Cadmium influx rates correlate with changes in the affinity of the biotic ligand, whereas those of Cu correlate with changes in both site affinity and capacity. A relationship between metal influx rate and ligand character asks whether toxicity is the result of accumulation at the biotic ligand or the rate at which metal is transported by that ligand.     

菠萝酪氨酸酶抑制活性组分的研究

以酶抑制动力学为跟踪方法,考察了菠萝中具双孢菇酪氨酸酶抑制作用的活性成分,并将之用于双孢菇的抗褐变,结果显示对酪氨酸酶有抑制作用的活性成分存在于乙醇组分中,且该活性成分对双孢菇酪氨酸酶的抑制作用属于不可逆抑制;5%菠萝汁对双苞菇浆褐变的抑制率54.8%,0.4%乙醇组分65.1%.     

Beef hamburgers enriched in lycopene using dry tomato peel as an ingredient

The direct addition of dry tomato peel (DTP) to hamburgers may be useful both to obtain a new product enriched in lycopene and for providing a use for this by-product from the tomato industry. In this study, different amounts of DTP (0–6.0% w/w) were added to raw and cooked hamburgers, and the effects on the meat’s physico–chemical and sensorial characteristics were studied. The maximum DTP concentration compatible with good sensory acceptability and high lycopene content was determined. Addition of DTP increased the colour parameters a^∗ and b^∗ of raw and cooked hamburgers, and modified all textural properties probably because of the presence of fibre. The hardness values of cooked samples was significantly higher in the batch containing 6% DTP (67.6 N) than in a control batch (50.9 N, p < 0.05). The addition of DTP to 4.5% results in hamburgers with good overall acceptability and a lycopene content of 4.9 mg/100 g of cooked hamburger.     

水浴振荡辅助酶法提取双孢蘑菇多糖的工艺研究

为了提高双孢蘑菇多糖的提取率,本实验初步通过单因素实验和正交实验研究水浴振荡辅助酶法提取双孢蘑菇多糖的工艺条件,研究结果表明:其最佳工艺条件为:料液比为1∶40、振荡频率为40r/min、酶用量为1.2%、pH为6.5、酶解温度为65℃、酶解时间为120min。实验结果表明,双孢蘑菇多糖的提取率可达2.31%。