Factors affecting the survival of dace, Leuciscus leuciscus (L.), in the early post-hatching period

Young dace fry were stocked into nylon mesh cages at densities ranging from 0·044 to 7·230 1^-1, and the cages anchored in a backwater area where the fry gathered naturally. The fry began feeding on small organisms drifting into the cages 2-4 days after hatching. The growth rate of the fry was inversely proportional, and the death rate directly proportional, to initial density. Soon after the exhaustion of endogenous food reserves (as determined from unfed fry), there was a period of massive mortality at the highest initial densities, probably due to starvation. After 20 weeks, the cages stocked at the two highest initial densities contained the lowest biomass of fry. Transfer of fry to cages with a larger mesh size produced increased growth and 46% survival over 20 weeks at the lowest initial density. These fry reached an overwintering length of 35·5 mm compared with 48·0 mm for naturally occurring fry.     

Behavioral thermoregulation of Bulla gouldiana (Gastropoda: Opisthobranchia: Cephalaspidea)

1. 1. The preferred temperature of Bulla gouldiana is 26.7–28.7°C.

2. 2. In constant scotophase, photophase, and light and dark photoperiod the organisms do not have a diel cycle of thermoregulation.

3. 3. It takes the animal 6–16 h to reach the preferred temperature.

4. 4. The lowest and highest temperatures visited were 11 and 33°C.

5. 5. Spawning of the species occurred in the thermal gradient between 27 and 28.5°C.

     

新疆的小麦品种（系）麦谷蛋白优质亚基分布规律研究

麦谷蛋白亚基对小麦品质有重要影响,优质亚基的利用是小麦品质遗传改良的重要途径。为了探讨新疆小麦优质亚基的分布规律,利用已开发的优质亚基和1B/1R易位系的分子标记,对新疆1242份小麦品种资源进行检测,结果表明,在新疆小麦品种资源中,优质亚基2*、7+8、5+10、glu A3d、glu B3b、glu B3d、glu B3g的分布频率依次为20.2%、22.0%、21.9%、16.9%、14.3%、11.9%、10.3%;1B/1R易位系的分布频率为12.6%。在冬小麦品种资源中,国外品种(系)5+10、1B/1R易位系的分布频率均最高,7+8、glu B3d、glu B3g的分布频率均最低;审定品种2*、glu B3d、glu B3g的分布频率均最高。在春小麦品种资源中,国外品种(系)glu B3d的分布频率最高;国内品种(系)5+10、glu A3d、1B/1R易位系的分布频率最高,2*、glu B3d的最低;审定品种2*的分布频率最高,glu B3b、glu B3g的最低。总体来看,新疆春小麦优质亚基的分布频率总体高于冬小麦;导入LMW-GS优质亚基是新疆小麦品质进一步改良的重要方向;地方品种是LMW-GS优质亚基的良好供体。从1242份新疆小麦品种(系)中挑选出兼含多个优质亚基的冬、春小麦品种(系)各21份、24份,可在小麦品质遗传改良中加强利用。     

中亚热带13种树种幼苗叶片和细根可溶性有机碳的数量特征和结构特征

植物叶片和细根输入的可溶性有机碳(Dissolved organic carbon, DOC)是森林生态系统最活跃的组成部分,对生态系统的碳循环有重要作用。以中亚热带13种典型树种为研究对象,测定其幼苗叶片和细根(0—1 mm和1—2 mm)的碳氮含量,淋溶产生的DOC浓度以及傅里叶红外光谱特征,分析不同树种和不同器官之间DOC的数量特征和结构特征。结果表明：(1)浙江桂在叶片和细根(0—1 mm和1—2 mm)的总碳含量上最高,竹柏在叶片和0—1 mm细根的总碳含量上最低,观光木在1—2 mm细根的总碳含量上最低。花榈木和罗汉松在叶片的总氮含量上分别为最高和最低,木荚红豆和观光木分别在0—1 mm和1—2 mm细根的总氮含量上最高,冬青在细根(0—1 mm和1—2 mm)的总氮含量上最低。(2)刨花楠、闽楠和浙江桂等樟科树种在叶片淋溶产生的DOC浓度上最高,而罗汉松和和竹柏等罗汉松科树种在叶片淋溶产生的DOC浓度上最低;花榈木和木荚红豆等红豆属树种在细根(0—1 mm和1—2 mm)淋溶产生的DOC浓度上最高;刨花楠、闽楠和浙江桂等樟科树种在细根(0—1 mm和1—2 mm)淋溶产生...     

Di‐2‐ethylhexyl phthalate (DEHP) exposure disturbs lipid metabolism in juvenile yellow catfish Tachysurus fulvidraco

This study was conducted to determine the mechanism by which di‐2‐ethylhexyl phthalate (DEHP) exposure influences lipid metabolism of juvenile yellow catfish Tachysurus fulvidraco. Fish were exposed to three DEHP concentrations (0, 0·1 and 0·5 mg l^?1 DEHP) for 8 weeks. Fatty acid synthase (FAS) activity significantly decreased with increasing DEHP concentrations, the highest value was in the Tween control group, whereas the lowest activities of carnitine palmitoyltransferase (CPT) and lipoprotein lipase (LPL) were in this group. The messenger (m)RNA levels of 6‐phospho‐gluconate dehydrogenase (6PGD), FAS and acetyl‐CoA carboxylase a (ACCa) significantly increased with increasing DEHP concentration, the highest values were in the 0·5 mg l^?1 DEHP group. The mRNA level of peroxisome proliferator‐activated receptor γ (PPARγ) was lower in Tween control than in fish exposed to 0·1 and 0·5 mg l^?1 DEHP. The highest mRNA level of ACCb was in the 0·1 mg l^?1 DEHP group. These results indicate that DEHP exposure can disturb lipid metabolism at the enzymatic and mRNA levels in Pelteobagrus fulvidraco.     

不同土层测墒补灌对冬小麦耗水特性与光合速率和产量的影响

于2012—2014年两个冬小麦生长季,在大田条件下设置：全生育期不灌水(W₀)处理,当地定量节水灌溉(拔节期和开花期均灌水60 mm,W₁)处理,依据0～20 cm (W₂)、0～40 cm (W₃)、0～60 cm (W₄)和0～140 cm (W₅)土层土壤含水量测墒补灌处理,于拔节期和开花期补灌至土壤相对含水量为田间持水量的65%和70%,研究依据不同土层土壤含水量测墒补灌对冬小麦耗水特性、光合速率和籽粒产量的影响.结果表明：各处理拔节期灌水量为W₁、W₄＞W₃＞W₂、W₅,开花期灌水量和总灌水量均为W₅＞W₁、W₄＞W₃＞W₂,W₃总耗水量显著高于W₂处理,与W₁、W₄和W₅处理无显著差异.W₃土壤贮水消耗量高于W₁、W₄和W₅处理,其中,W₃在拔节至开花阶段和开花至成熟阶段对40～140 cm和60～140 cm土层土壤贮水消耗量均显著高于其余灌水处理.灌浆中期W₃处理小麦旗叶光合速率、蒸腾速率和水分利用效率最高,W₁和W₄处理次之,W₀处理最低.W₃处理两个生长季的籽粒产量分别为9077和9260 kg·hm^-2,水分利用效率分别为20.7和20.9 kg·hm-2·mm^-1,均显著高于其余处理,灌溉水生产效率最高.综合考虑灌水量、籽粒产量和水分利用效率,小麦拔节期和开花期适宜进行测墒补灌的土层深度为0～40 cm.     

Endometrial prostaglandin E2-binding sites in the pig: characterization and changes during the estrous cycle and early pregnancy

Because prostaglandins (PGs) are thought to mediate, in part, endometrial responses at implantation in a number of species and because pig conceptuses are capable of producing PGs, we have characterized the binding of [3H]PGE2 to endometrium obtained from pigs during the estrous cycle and early pregnancy. Binding of [3H]PGE2 to a membrane preparation obtained from endometrium was temperature- and pH-dependent, and reversible. Pretreatment of the membrane preparation with proteolytic enzymes, phospholipase A2, or heat reduced subsequent specific binding of [3H]PGE2. PGE1 and PGE2 competed equally for binding, whereas relative cross-reactivity for other prostanoids and compounds tested was less than 5%. Scatchard analysis of specific binding suggested that two classes of binding sites were present, a high-affinity binding site with an apparent dissociation constant (Kd) of approximately equal to 6 pM, and a lower-affinity site with an apparent Kd of approximately equal to 3 nM. For the high-affinity binding site, estimates of apparent Kd did not differ between days of the estrous cycle, but maximum binding capacity did change, being lowest on Day 10 and highest on Days 0-5 of the cycle. For the lower-affinity binding site, estimates of the apparent Kd differed, being lowest on Day 10 and highest on Day 15; numbers of binding sites were lowest on Day 5 and highest on Day 15. Estimates of these variables on Day 15 of pregnancy did not differ significantly from Day 15 of the cycle. These data are consistent with the presence of PGE receptors within the endometrium of the pig.     

Polyesters Based on Linoleic Acid for Biolubricant Basestocks: Low-Temperature,Tribological and Rheological Properties

Presently, plant oils which contain high percentage of linoleic acid 1 are perceived to be a viable alternative to mineral oil for biolubricant applications due to their biodegradability and technical properties. In order to get biodegradable lubricant, triester derivatives compounds (1–5) were synthesized and characterized. The processes involved were monoepoxidation of linoleic acid 2, oxirane ring opening 3, esterification 4 and acylation 5. The structures of the products were confirmed by FTIR, ¹H and ¹³C-NMR and LC-MS. The results that showed lowest temperature properties were obtained for triester 5, with a pour point value (PP) of -73°C, highest onset temperature (260°C) and lowest volatility at 0.30%. Viscosity index (VI) increased for the ester’s synthetic compounds (2, 3, 4, 5), while the PP decreased. This behavior is the result of the increase of the chain length of the branching agents. Triester based linoleic acid has improved properties such as low-temperature and tribological properties. These results will make it feasible for plant oil to be used for biolubricants, fuels in chain saws, transmission oil and brake fluid.     

三种高盐苯胺废水对细菌群落结构的影响

采用PCR-DGGE技术分析了含有不同CODCr、盐、总磷、氨态氮、氯离子、苯胺浓度的3种高盐苯胺废水(1#、2#、3#)驯化的细菌群落结构变化,从分子水平阐明高盐苯胺废水对细菌群落结构的影响.结果表明,不同浓度高盐苯胺废水驯化过程中,2#废水随着浓度的升高,细菌群落多样性逐渐下降;1#废水驯化的细菌群落多样性指数以5%的废水最高,20%与40%的废水最低;3#废水驯化的细菌群落多样性指数以0%和5%的废水最高,20%的废水最低.不同废水对细菌群落多样性有不同的影响,表明适应和突变是驯化过程中细菌适应环境的一个重要作用力.3种不同高盐苯胺废水驯化的细菌群落多样性指数与CODCr、盐含量之间均存在显著负相关,但与氯离子和苯胺含量之间相关不显著.3种废水驯化的细菌的遗传多样性有较大差异,多态位点百分率、Shannon's信息指数和Nei's指数均以3#废水最高,1#废水次之,2#废水最低.但遗传多样性指标与CODCr、盐含量、氯离子和苯胺含量之间均相关不显著.可知细菌群落多样性的变化是由于废水中所含的污染物质的综合作用结果,而非单一的因素.3种废水的5种不同浓度驯化细菌之间的平均遗传距离分别为0.4724、0.4350和0.4902,其中3#废水驯化的细菌遗传变异最大.聚类分析表明,5种不同浓度高盐苯胺废水驯化细菌均可明显地分为两组.1#和2#废水均为0%、5%和10%废水驯化细菌聚成一组,而20%和40%废水驯化细菌聚成另一组; 3#废水为0%与5%废水驯化细菌聚成一组,而10%、20%和40%废水驯化细菌聚成另一组.不同的废水由于水质背景值不同,选择压力不同,导致细菌突变的阈值不同,使得诱导细菌变异程度不同,从而最终引起细菌群落结构的不同.驯化过程中微生物种群的变化使得整个微生物群落能够快速适应外部环境变化.     

The influence of biomass temperature on biostabilization-biodrying of municipal solid waste

A laboratory study was carried out to obtain data on the influence of biomass temperature on biostabilization-biodrying of municipal solid waste (initial moisture content of 410 g kg wet weight (w.w.)(-1)). Three trials were carried out at three different biomass temperatures, obtained by airflow rate control (A = 70 degrees C, B = 60 degrees C and C = 45 degrees C). Biodegradation and biodrying were inversely correlated: fast biodrying produced low biological stability and vice versa. The product obtained from process A was characterized by the highest degradation coefficient (166 g kg TS0(-1); TS0(-1) = initial total solid content) and lowest water loss (409 g kg W0(-1); W0 = initial water content). Due to the high reduction of easily degradable volatile solid content and preservation of water, process A produced the highest biological stability (dynamic respiration index, DRI = 141 mg O2 kg VS(-1); VS = volatile solids) but the lowest energy content (EC = 10,351 kJ kg w.w.(-1)). Conversely, process C which showed the highest water elimination (667 g kg W0(-1)), and lowest degradation rate (18 g kg TS0(-1)) was optimal for refuse-derived fuel (RDF) production having the highest energy content (EC = 14,056 kJ kg w.w.(-1)). Nevertheless, the low biological stability reached, due to preservation of degradable volatile solids, at the end of the process (DRI = 1055 mg O2 kg VS(-1)), indicated that the RDF should be used immediately, without storage. Trial B showed substantial agreement between low moisture content (losses of 665 g kg W0(-1)), high energy content (EC = 13,558 kJ kg w.w.(-1)) and good biological stability (DRI = 166 mg O2 kg VS(-1)), so that, in this case, the product could be used immediately for RDF or stored with minimum pollutant impact (odors, leaches and biogas production).