Geochemistry of mafic igneous rocks of the northern Prince Charles Mountains,Antarctica

Rare mafic dykes, which intrude 1000 Ma high‐grade metamorphic rocks of the northern Prince Charles Mountains‐Mawson Coast area, are compositionally distinct from abundant early to middle Proterozoic tholeiite dykes, which are confined to Archaean or early Proterozoic terrains in the southern Prince Charles Mountains and elsewhere in East Antarctica, and which have therefore proved useful as stratigraphic markers. The younger dykes (and extrusive rocks) are a composition‐ally heterogeneous group with a wide range of ages (at least Cambrian to Eocene), although most are of K‐rich alkaline composition or have alkaline affinites. Their strong enrichment in highly incompatible elements (Rb, Ba, Th, Nb, K, Pb, Th and U) relative to less incompatible elements (La, Ce and P) suggests derivation by partial melting of more enriched mantle source regions than those of most of the Proterozoic tholeiite suites. However, unlike the latter, many incompatible element ratios have been significantly affected by fractional crystallisation and possibly also by the presence of residual minor phases during low degrees of melting.     

Effect of stocking density on performances of juvenile turbot (Scophthalmus maximus) in recirculating aquaculture systems

Limited information has been available about the influence of loading density on the performances of Scophthalmus maximus, especially in recirculating aquaculture systems (RAS). In this study, turbot (13.84±2.74 g; average weight±SD) were reared at four different initial densities (low 0.66, medium 1.26, sub-high 2.56, high 4.00 kg/m²) for 10 weeks in RAS at 23±1°C. Final densities were 4.67, 7.25, 14.16, and 17.47 kg/m², respectively, which translate to 82, 108, 214, and 282 percent coverage of the tank bottom. Density had both negative and independent impacts on growth. The final mean weight, specific growth rate (SGR), and voluntary feed intake significantly decreased and the coefficient of variation (CV) of final body weight increased with increase in stocking density. The medium and sub-high density groups did not differ significantly in SGR, mean weight, CV, food conversion rate (FCR), feed intake, blood parameters, and digestive enzymes. The protease activities of the digestive tract at pH 7, 8.5, 9, and 10 were significantly higher for the highest density group, but tended to be lower (not significantly) at pH 4 and 8.5 for the lowest density group. The intensity of protease activity was inversely related to feed intake at the different densities. Catalase activity was higher (but not significantly) at the highest density, perhaps because high density started to induce an oxidative effect in turbot. In conclusion, turbot can be cultured in RAS at a density of less than 17.47 kg/m². With good water quality and no feed limitation, initial density between 1.26 and 2.56 kg/m² (final: 7.25 and 14.16 kg/m²) would not negatively affect the turbot cultured in RAS. For culture at higher density, multi-level feeding devices are suggested to ease feeding competition.     

饲料粗蛋白含量对刺参消化酶及消化道结构的影响

本实验以鱼粉、酪蛋白以及藻粉等为主要原料配制了粗蛋白质量分数为12%、16%、20%、24%、28%、32%的6种半精制刺参(Apostichopus japonicus)饲料,研究饲料中粗蛋白含量对刺参生长、蛋白酶和淀粉酶活性以及肠道结构的影响。结果表明,刺参饲料中粗蛋白含量对刺参的生长、饲料系数、蛋白质效率以及消化道中蛋白酶和淀粉酶活性都有明显影响,肠道蛋白酶和淀粉酶活性对饲料粗蛋白含量有适应性,随饲养时间也有适应性变化。饲料中粗蛋白含量对刺参肠道结构也有一定的影响。     

印尼热泉中产嗜热碱性蛋白酶菌株筛选及酶学性质研究

采用MSM寡营养培养基从印度尼西亚Pantai cermin,Kalianda和Banyuwedang三个地区的热泉水样、泥样以及沉积物样品中分离获得细菌菌株,通过检测蛋白酶产生透明圈和福林酚蛋白酶活性测定相结合的方法,从中筛选出1株产嗜热蛋白酶的菌株PBI,该菌株经初步鉴定为短杆菌属(Brevibacillus),并对其酶学性质进行了研究。结果表明,菌株PBI产蛋白酶的最适酶活温度为60℃,最适pH值为8.0～9.0,具有较好的热稳定性和pH稳定性,60℃时酶的半衰期为30min,70℃条件下20min仍保持46.1%的酶活,该酶在pH值为5.0～9.0范围的缓冲液中酶活相对稳定。其产嗜热蛋白酶的酶活力最高可达到60.53U/mL,在100℃条件下仍能保留26.37%的相对酶活。Fe2+,Fe3+,Cu2+和Zn2+对嗜热蛋白酶活性具有明显的抑制作用。该嗜热蛋白酶对EDTA敏感,苯甲基磺酰氟(PMSF)、亮抑酶肽(Leupeptin)、苄眯(Benzamidine)和胃蛋白酶抑制剂(Pepstain A)对该嗜热蛋白酶都有一定的抑制作用,说明其酶活性受到丝氨酸、半胱氨酸残基的影响。结果表明,该菌株是1株具有进一步改造利用价值的产蛋白酶菌株。     

氨氮慢性胁迫对刺参免疫酶活性及热休克蛋白表达的影响

以初始体重为(50.50±1.67)g左右的刺参(Apostichopus Japonicus Selenka)为研究对象,研究了不同氨氮浓度对刺参体壁和体腔液中酸性磷酸酶(ACP)、碱性磷酸酶(AKP)、超氧化物歧化酶(SOD)和过氧化氢酶(CAT)活性及HSP70表达的影响。20d慢性毒性实验研究结果表明:(1)刺参体壁和体腔液ACP、AKP活性在0.51和2.04mg/L氨氮浓度下表现出先上升后降低的趋势,而在5.09、10.19和50.93mg/L下,则表现出降低的趋势;(2)不同浓度氨氮胁迫下,刺参体壁CAT活性均呈现降低趋势,且与氨氮浓度呈现显著的负相关性(P<0.05),而刺参体腔液CAT活性在0.51、5.09、10.19和50.93mg/L浓度下则均随取样时间而降低;(3)在氨氮浓度0.51～5.09mg/L时,刺参体壁和体腔液SOD活性均表现出不同程度的先增高后降低的趋势,而在高浓度下则与氮氮浓度显著负相关;(4)在氨氮胁迫下,刺参体壁、呼吸树、肠道和体腔液中HSP70表达量迅速升高,氨氮胁迫第5天时检测到达到最高;随后各组织HSP70的表达量缓慢降低,但在氨氮胁迫第20天时,各组织HSP70的表达量仍显著高于氨氮胁迫前的水平(P<0.05)。各组织中HSP70最高表达量与氨氮浓度呈现明显的正相关性。综合本研究结果可以看出,随着氨氮胁迫浓度的增加和胁迫时间的延长,刺参免疫酶活性趋于降低,同时机体清除自由基的能力下降,机体非特异性免疫防御系统遭到损伤。而HSP70表达量维持在较高水平,可能对于增强机体的抗逆性具有重要的作用。     

不同灌水量对碱化土的影响

碱化土壤上不同定额灌水量试验研究表明,电导率与可溶性盐是成正比关系,电导率、可溶性盐与pH成反比关系。灌水量对土壤总盐及盐分组成中CT、SO4^2-的影响较人;随着灌水量的增加,表层土壤中HCO3^-增加,pH上升。灌水量必须大于一定的量才具有洗盐作用。     

金雀异黄素对金鱼消化酶活性的影响

本文研究了0.2、2、20μg/g金雀异黄素腹腔注射金鱼(Carassius auratus) 7d后,金鱼肝胰脏和肠蛋白酶、淀粉酶和碱性磷酸酶活性的变化.结果表明:随金雀异黄素浓度的升高,金鱼肝胰脏和肠蛋白酶、淀粉酶及肠碱性磷酸酶活性都有所降低.0.2μg/g金雀异黄素处理组,金鱼蛋白酶和淀粉酶活力降低并不显著,而肠碱性磷酸酶活力显著下降(P＜0.05);2μg/g金雀异黄素处理组,金鱼蛋白酶和淀粉酶活力显著下降,碱性磷酸酶活力表现极显著下降(P＜0.01),仅为对照组的44％;20μg/g金雀异黄素处理组,金鱼蛋白酶和淀粉酶活力极显著下降,其中肠蛋白酶活性降了90％以上.本文证实了较高浓度的金雀异黄素能显著降低金鱼主要消化酶的活性,进而影响金鱼正常生长,但较低浓度的金雀异黄素对金鱼消化酶无显著影响.研究结果为大豆蛋白在水产养殖中的适量应用提供了参考数据.     

碱式水解法提取红土分子化石: 以安徽宣城更新世网纹红土为例

红土中种类丰富的分子化石为红土古生态研究提供了直接证据, 但较低含量的分子化石限制了传统索氏抽提方法的推广应用.本次研究尝试性地运用碱式水解法提取安徽宣城更新世红土中的分子化石, 在25g样品中检测到了含量明显、种类丰富的有机物, 且该方法可以显著地降低空白污染, 这说明碱式水解法在分子化石含量低的地质体(如红土) 研究中具有一定的应用潜力.本次研究检测出除了传统索式抽提得到的正构烷烃、脂肪酸、脂肪醇等以外, 还提取到了二元羧酸这一重要化合物, 它的存在为网纹红土可能形成于多水环境提供了新的证据.测试样品中各类分子化石组合信息显示出红土有机物以微生物为主的来源特征, 表明网纹红土形成过程受到了微生物活动的影响, 同时伴有大量低等菌、藻来源有机质的输入, 初步结果为红土形成环境研究提供了新的证据.      

山东城顶山地区牛山旋回火山岩地球化学特征及幔源分析

通过探讨山东城顶山地区牛山旋回火山岩地球化学特征,对其幔源特征进行分析。地球化学特征分析结果表明城顶山地区的岩石为高钾岩石,具有贫硅铝、富镁钙的特征及明显的富钛特征;微量元素分析结果显示,大离子亲石元素Sr含量较高,牛山旋回火山岩的稀土元素总量∑REE在140～177μg/g之间,LREE/HREE在3.58～4.90之间,显示出岩浆分异程度低、分馏不明显的特点,分配型式为轻稀土弱富集型平缓的右倾曲线,与裂谷玄武岩相似,指示了其源区的特点,推测其来源为地幔物质熔融形成的原生岩浆。分析结果可作为进一步研究山东大陆碱性玄武岩的参考。     

准噶尔盆地西北缘二叠系风城组硅质岩地球化学特征及成因

准噶尔盆地西北缘二叠系风城组内的云质岩、硅质岩是致密油藏重要的储集岩,目前对云质岩和与之伴生的硅质岩成因存在较大争议。通过岩心观察和对硅质岩的主量、微量、稀土及硅同位素的综合研究,以期揭示硅质岩的成因。研究表明,风城组中的硅质岩SiO2含量变化范围为55.15%~85.61%,为不纯的云质硅质岩,其内含有较多热水沉积矿物和碱湖沉积成因的盐类矿物。云质硅质岩主要围绕热液喷口分布,它们常与白云岩呈纹层状、条带状互层。云质硅质岩中硼异常富集,硼含量介于90×10^-6~10000×10^-6之间,平均680×10^-6,与盐类矿物硅硼钠石有关,反映了碱湖沉积成因;Sr/Ba值均大于1,Th/U值多在0.62~2.06之间,Sm/Nd值多在0.20~0.24之间。云质硅质岩的稀土配分显示出Eu负异常、Ce负异常或弱正异常及轻稀土相对重稀土富集的特征。δ^30Si值介于0.39‰~1.88‰之间,其δ^30Si和微量元素特征不反映典型热水成因。云质硅质岩的地质产状和地球化学特征共同表明,风二段和风三段云质硅质岩主要为热水和碱湖的混合沉积成因。硅质岩形成受喷口的位置、热水喷流期和各喷口喷流热水的温度等多方面因素的控制,硅质岩形成时存在多个喷口,在相对封闭的高盐度—碱性还原环境下的热水喷流期,热水与碱湖湖水混合,混合水沉积形成硅质、盐类矿物及白云石,最终形成含盐的云质硅质岩;热水喷流间歇期形成碱湖成因的含盐云质岩。