中国栽培平菇的酯酶同工酶分析

采用电泳技术对我国大规模栽培的64个平菇商业菌株进行酯酶同工酶分析。结果表明，我国栽培平菇菌种多样性丰富，64个菌株有44个酶谱类型，不同菌株有各自特有的酯酶同工酶酶谱。聚类分析表明，供试菌株在60％相似水平上分为6大类：第一类包括以白黄侧耳为代表的21个菌株；第二类包括以德国引进菌株为代表的6个未定种名菌株；第三类包括7个白黄侧耳与佛罗里达侧耳杂交的杂交种及4个未定种名菌株；第四类包括以佛罗里达侧耳为代表的5个菌株；第五类包括以糙皮侧耳为代表的14个菌株；第六类包括以肺形侧耳为代表的7个菌株。     

三种酶制备牡蛎蛋白水解物的抗氧化活性和功能特性分析

目的：比较分析木瓜蛋白酶、胃蛋白酶和胰蛋白酶三种不同酶水解牡蛎获得的蛋白产物抗氧化活性和功能特性。方法：采用木瓜蛋白酶、胃蛋白酶和胰蛋白酶三种不同酶水解牡蛎蛋白获得水解物,并分别测定它们的在不同pH下的溶解度、乳化性以及不同浓度水解物的还原能力、DPPH自由基清除率和Fe^{2 +}螯合能力。结果：表明三种酶水解物都有较高的溶解度(p＜0.01),胰蛋白酶产生的水解物溶解高度达94.8％(p＜0.05);水解物溶解度和乳化活性指数在pH4显著降低(p＜0.05)。牡蛎蛋白质水解产物的还原能力、DPPH自由基清除能力和金属螯合活性随浓度的增加而增强,其中胰蛋白酶和胃蛋白酶抗氧化能力较强(p＜0.01)。结论：三种蛋白酶水解牡蛎蛋白可获得抗氧化活性强、溶解度高的水解物,并受浓度和pH的影响,它们的水解物可作为一种潜在的抗氧化功能多肽利用。     

Trichoderma species associated with green mould disease of Pleurotus ostreatus and their sensitivity to prochloraz

Green mould disease causes serious economic losses in Pleurotus ostreatus crops worldwide, including in Italy, where prochloraz is the only chemical fungicide allowed to control the disease. The effectiveness of the doses 0.01, 0.05, 0.25 and 1.25 μL L⁻¹ (field dose) of prochloraz (Sponix Flow, 450 g L⁻¹), against colony growth rate and spore germination of Trichoderma pleuroti, T. pleuroticola and T. guizhouense strains on wheat straw extract agar plates were evaluated. Complete inhibition of Trichoderma pleuroti and T. pleuroticola growth was shown by the field dose of prochloraz, and also by the 0.25 μL L⁻¹ dose for T. pleuroti. Complete inhibition of spore germination occurred for all Trichoderma strains at field dose, and at 0.25 μL L⁻¹ for T. pleuroti strains. In in vivo assays, the effect of prochloraz doses 0.05, 0.25 and 1.25 μL L⁻¹ on colonization of straw substrate by T. pleuroti, T. pleuroticola and T. guizhouense inoculated at two spore densities (10² and 10⁵ spores mL⁻¹) immediately after P. ostreatus spawn was studied. Trichoderma pleuroti and T. pleuroticola were both responsible for green mould disease, whereas T. guizhouense was not pathogenic. Trichoderma pleuroti was more aggressive than T. pleuroticola. Prochloraz was effective against T. pleuroti at the field dose, and against T. pleuroticola at 0.25 and 1.25 μL L⁻¹. The study on Trichoderma × Pleurotus interaction type showed that Trichoderma species were active against the mycelial growth of P. ostreatus by competition for space and nutrients, and neither hyphal interaction nor effect by volatile or nonvolatile metabolites occurred.     

ERIC-PCR技术在平菇菌株鉴定中的应用

研究了ER IC-PCR技术在平菇栽培菌株鉴定中的应用.结果表明,在22个供试平菇菌株和对照香菇菌株中,ER IC-PCR扩增出的条带清晰,重复性好,多态性高.聚类分析表明,在聚类重新标定距离为15的水平上,23个菌株聚类成8大类群:糙皮侧耳栽培菌株分别归属第1和第2大类群;秀珍菇5号、4011、白灵菇2号、杏鲍菇、鲍鱼菇和香菇分别独立地聚类为不同的大类群.在聚类重新标定距离为20时,鲍鱼菇和香菇聚类在一起,其他平菇菌株聚类在一起.这表明ER IC-PCR技术可以应用于平菇栽培菌株的鉴定,但也说明该技术在食用菌分类鉴定应用上的局限性,同时也说明食用菌需要多相分类鉴定.     

牡蛎壳在水质改良中的应用

牡蛎壳能有效减少水体中多种污染物的含量,具有良好的水质改良能力。本文综述了牡蛎壳的主要成分、结构,以及牡蛎壳改良水质的原理,介绍其在水处理中用来脱磷、除重金属、去染料及其他污染物的研究、应用现状,并对其开发应用前景进行了展望。     

Production of inbred larvae through self‐fertilization using oocytes and cryopreserved sperm from the same individuals after sex reversal in eastern oyster Crassostrea virginica

The eastern oyster Crassostrea virginica can change sex which makes self‐fertilization possible if sperm can be cryopreserved. In this study, small (~1 year old) and large (~2–3 years old) oysters were biopsied for sperm collection. Survival of the biopsied oysters after 1 year was 50% for small oysters and 17% for large oysters. Oocytes were collected from sex‐reversed females, and self‐fertilized with cryopreserved sperm. Of the 24 cryopreserved samples, 14 individuals had ≤1% fertility when crossed with oocytes from unrelated females, indicating that the cryopreserved sperm had reduced fertility. The other 10 individuals had a fertility of 39 ± 25% when crossed with oocytes from unrelated females (non‐selfing), but showed a significantly lower success of self‐fertilization (12 ± 16%) (P = 0.008), while aliquots of the same oocytes had a fertilization of 83 ± 11% when crossing with fresh sperm. Larvae were produced at day 3 in the self‐fertilized families (12–94% of the fertilized oocytes), and survived to eyed‐larvae stage at days 11–14. Genotyping with 9 microsatellite markers confirmed that the larvae resulted from self‐fertilization in four families. This study demonstrated the feasibility of creating self‐fertilized inbred lines of oysters by use of non‐lethal sperm collection and cryopreservation.     

硝化细菌浓度及滤料对养殖水中氨氮处理效果的影响

分别研究了不同硝化细菌浓度(0、20、60、120 mL/100 L)和不同微生物滤料(珊瑚石、锅炉煤渣、牡蛎壳)对养殖水中氨氮处理效果的影响。结果显示,添加硝化细菌后,水体中的氨氮浓度呈现下降趋势,在8～12 h出现极低值后,开始上升,但上升速度较慢;随着水体中硝化细菌添加量的增加,水体中的氨氮浓度下降速度加快;水体中亚硝酸氮浓度呈现先上升后下降的趋势,并在4～6 h出现极高值,然后迅速下降,且硝化细菌添加量越高,下降速度越快。硝化细菌对以珊瑚石和锅炉煤渣为滤料的养殖水体中氨氮和亚硝酸氮的处理效果显著优于牡蛎壳,但珊瑚石和锅炉煤渣之间无显著差异。综合试验结果,应急水质处理时,硝化细菌菌剂的添加量以一次60 mL/100 L(或以活菌计数为1.2×109个/100 L)、间隔24 h添加1次为宜;经过脱硫筛选之后的锅炉煤渣可以作为循环水养殖用滤料。     

南澳贝藻混养互利机制的初步研究

以牡蛎和龙须菜为试验材料,进行了两个阶段不同投放比例的室内模拟混养试验,试验周期均为4周,各试验组分别为:对照组、龙须菜单养组、牡蛎单养组、牡蛎龙须菜低密度混养组、牡蛎龙须菜中密度混养组和牡蛎龙须菜高密度混养组,其中除对照组和龙须菜单养组外,各试验组牡蛎密度均为27只/m3,第一阶段龙须菜密度分别为:0,47,0,47,94,188g/m3,第二阶段龙须菜密度为:0,158,0,158,316,854g/m3。定期采样测定水体中营养盐(NO2-N,NO3-N,NH4-N,PO4-P)的含量及养殖生物的生长情况。试验结果表明,第一阶段试验结束时,投放牡蛎的试验组与未投放牡蛎的试验组水体氮、磷含量差异显著(P0.05)。第二阶段试验结束时,投放牡蛎的各试验组磷酸盐和硝酸盐含量差异显著(P0.05),高密度混养组的磷酸盐含量和硝酸盐含量与牡蛎单养组相比分别降低了43%、30%,说明龙须菜明显吸收了水体中的氮、磷,混养系统氮、磷利用更为合理,其中龙须菜854g/m3,牡蛎27只/m3的高密度混养组投放密度最为合理。     

Capricious bioinvasions versus uncoordinated management strategies: how the most unlikely invaders can prosper under the current UK legislation framework

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1989—2010年广东沿海牡蛎体内锌的时空分布特征与污染水平分析

根据历史和调查资料,对1989—2010年广东沿海牡蛎体内锌(Zn)的时空分布特征和污染水平进行了分析与比较。结果表明,牡蛎体内Zn的浓度总平均值为211.5 mg/kg,从总体看其浓度出现频率呈对数正态分布。在时间上,牡蛎体内Zn总体平均浓度的分布呈阶段性变化,具体表现为1989—2007年Zn的浓度呈微弱降低的趋势,基本维持在197.0 mg/kg的水平;2007—2009年牡蛎体内Zn的浓度有明显升高的趋势,之后Zn的浓度有所降低。在空间上,粤东和粤西沿海牡蛎体内Zn浓度的变化均呈先降低后增加的趋势,且基本与广东沿海牡蛎体Zn平均浓度的变化趋势相同,而珠江口牡蛎体Zn的浓度水平相对较高并表现出趋于稳定的变化规律。单因子指数和非致癌性风险指数评价结果均表明,牡蛎体内Zn的总体不存在明显的污染,但从当前保护环境角度应当尽快设立我国水产品中Zn含量的限定标准。