Surface-skimming stoneflies: a possible intermediate stage in insect flight evolution

Insect wings appear to have evolved from gills used by aquatic forms for ventilation and swimming, yet the nature of intermediate stages remains a mystery. Here a form of nonflying aerodynamic locomotion used by aquatic insects is described, called surface skimming, in which thrust is provided by wing flapping while continuous contact with the water removes the need for total aerodynamic weight support. Stoneflies surface skim with wing areas and muscle power output severely reduced, which indicates that surface skimming could have been an effective form of locomotion for ancestral aquatic insects with small protowings and low muscle power output.     

真空包装草鱼片低温贮藏后微观结构及理化性质的变化

为研究真空包装草鱼片在低温条件下的变化,将真空包装草鱼片分别于-18、0、4、10℃贮藏15 d,以贮藏期间K值(ATP分解指数)的变化来评价其化学变化。结果表明:在0、4、10℃下贮藏15 d后,草鱼肌纤维间的空隙变大,由于鱼肉内水的结晶,在-18℃下肌纤维间的空隙达到最大(约100μm);随着贮藏时间的延长,鱼片的持水能力显著下降,-18℃下贮藏鱼片的持水能力最低,0、4℃贮藏鱼片的持水能力高于10℃贮藏鱼片;于较高温度(0、4、10℃)贮藏后,鱼肉的亮度值(L*)、红绿值(a*)和黄蓝值(b*)均较高,在-18℃低温贮藏后鱼肉的亮度值增加;随贮藏时间的延长,鱼片颜色(色差仪分析结果)趋向于红色值和黄色值增大;在-18℃贮藏15 d后,鱼片仍然新鲜,但质构变差。     

普通草鱼与脆化草鱼的肌肉特性比较

以9尾体重为（1 295.7±37.2）g的普通草鱼和9尾体重为（706.8±6.5）g脆化草鱼（脆肉鲩）为实验对象,对其肌肉理化及质构特性进行比较研究。结果显示：脆化草鱼肌肉粗蛋白含量高于普通草鱼（P<0.05）,粗脂肪和铁含量比普通草鱼低（P<0.05）,二者肌肉水分、粗灰分及钙、铬含量无显著差异;脆化草鱼肌肉pH、肌纤维密度和胶原蛋白含量均大于普通草鱼（P<0.05）;脆化草鱼在2 h和4 h的肌肉滴水损失低于普通草鱼（P<0.05）,但8 h后差别不大;脆化草鱼肌肉硬度和咀嚼力均比普通草鱼高（P<0.05）。对肉质性状指标分析表明,在一定范围内,肌纤维密度、pH、胶原蛋白有提高肉质品质的作用趋势;肌肉脂肪含量与肌肉硬度,肌纤维密度与肌肉滴水损失之间均呈显著负相关（P<0.05）。     

Predator-induced phenotypical change in body morphology in crucian carp

In a field experiment where the presence or absence of piscivorous pike (Esox lucius) in ponds was manipulated, the morphology of crucian carp (Carassius carassius) diverged, such that individuals became deeper bodied in pond sections with pike. A laboratory experiment confirmed that the presence of this predator induced a change in body morphology in the carp. Estimation of prey vulnerability to predation by pike, a gape-limited predator, revealed that this increase in body depth resulted in crucian carp reaching a size that provided refuge from predation. However, this change in morphology incurs a cost through an increase in drag when the carp are swimming. Because crucian carp are limited by resources in the absence of piscivores and by the substantial cost of the defensive morph in their presence, phenotypic plasticity should be the optimal strategy for this species.     

草鱼MyoD cDNA的克隆和序列分析

 用RACE技术从受精后约22 h的草鱼胚胎总RNA中扩增获得了草鱼MyoD基因的全序列,并对其序列进行了分析。结果表明，草鱼MyoD基因全长cDNA为1 597 bp,其中开放阅读框为825 bp，共编码275个氨基酸，结构分析表明该肽链第1～84个氨基酸为草鱼MyoD基因的Basic区,第98～142个氨基酸为草鱼MyoD基因的HLH结构域，该序列所编码的肽链没有信号肽；通过对比分析已知的GeneBank中其它脊椎动物MyoD基因发现，该基因编码的氨基酸肽链随动物由低等向高等进化有加长的趋势,且核苷酸以及推测的氨基酸同源性和动物之间的亲缘关系相一致；草鱼MyoD基因的克隆为研究家鱼的肌肉发育调控的机理以及肉质改良奠定了基础。     

不同饲料蛋白质水平条件下L-肉碱对鲤鱼生长和肌肉营养成分的影响

在不同饲料蛋白质水平（28％，32％，36％）条件下，于饲料中分别添加0，50，10，150，200，250mg/kgL肉碱，研究其对鲤鱼（Cyprinus carpioL.）生长和肌肉营养成分的影响。结果表明，试验期末添加150mg/kgL－肉碱处理组鲤鱼体重最大，低蛋白水平饲料添加L－肉碱后鲤鱼增重率最大，肌肉业蛋白质含量相对增加了3．13％，肌肉粗脂肪含量相对降低了11．45％，与对照组相比差异极显著。在不同饲料蛋白质含量相对增加了3．13％，肌肉粗脂肪含量相对降低了11．45％，与对照组相比差异极显著。在不同饲料蛋白质含量条件下，添加外源性L－肉碱可明显促进鲤鱼的生长，改善肉质质量，在较低蛋白质含量饲料中添加一定量L－肉碱，可使鲤鱼的生长速度和肌肉营养成分达到较高蛋白质含量饲料的水平。     

Thermoregulation in endothermic insects

On the basis of body weight, most flying insects have higher rates of metabolism, and hence heat production, than other animals. However, rapid rates of cooling because of small body size in most cases precludes appreciable endothermy. The body temperature of small flies in flight is probably close to ambient temperature, and that of flying butterflies and locusts is 5 degrees to 10 degrees C above ambient temperature. Many moths and bumblebees are insulated with scales and hair, and their metabolism during flight can cause the temperature of the flight muscles to increase 20 degrees to 30 degrees C above ambient temperature. Curiously, those insects which (because of size, insulation) retain the most heat in the thorax during flight, also require the highest muscle temperature in order to maintain sufficient power output to continue flight. The minimum muscle temperature for flight varies widely between different species, while the maximum temperature varies over the relatively narrow range of 40 degrees to 45 degrees C. As a consequence, those insects that necessarily generate high muscle temperatures during flight must maintain their thoracic temperature within a relatively narrow range during flight. Active heat loss from the thorax to the abdomen prevents overheating of the flight motor and allows some large moths to be active over a wide range of ambient temperatures. Bumblebees similarly transfer heat from the flight musculature into the abdomen while incubating their brood by abdominal contact. Many of the larger insects would remain grounded if they did not actively increase the temperature of their flight muscles prior to flight. Male tettigoniid grasshoppers elevate their thoracic temperature prior to singing. In addition, some of the social Hymenoptera activate the "flight" muscles specifically to produce heat not only prior to flight but also during nest temperature regulation. During this "shivering" the "flight" muscles are often activated in patterns different from those during flight. The muscles contract primarily against each other rather than on the wings. However, the rate of heat production during shivering and flight is primarily a function of the action potential frequency rather than of the patterns of activation. Thermoregulation is a key factor in the energetics of foraging of some of the flower-visiting insects. The higher their muscle temperature the more flowers they can visit per unit time. When food supplies are ample, bees may invest relatively large amounts of energy for thermoregulation. While shivering to maintain high body temperatures during the short intervals they are perched on flowers (as well as while in the nest), bumblebees often expend energy at rates similar to the rates of energy expenditure in flight. Unlike vertebrates, which usually regulate their body temperature at specific set points, the body temperature of insects is labile. It often appears to be maintained near the lower temperature at which the muscles are able to perform the function at hand. The insects' thermal adaptations may not differ as much from those of vertebrates as previously supposed when size, anatomy, and energy requirements are taken into account.     

几种淡水商品鱼背、腹肉一般成分的季节变化

本文研究了鲢、鳙、草鱼、团头鲂、鲫背、腹肉蛋白质、脂肪等的季节变化及其有关营养、风味特点，发现5种鱼背肉脂肪含量12个月平均值均低于1％；蛋白质含量平均值在17．3—18．5％之间．不存在季节变化；是一种典型的高蛋白、低脂肪食物。反之，腹肉脂肪含量在2．2—9．7％之间．具有较多的脂肪和较好的风味。针对这种特点．鲢、鳙、草鱼等大型鱼采取背部、腹部分别加工是可取的。此外还测定证实鲢肌肉中含有较多的EPA和DHA。     

几种淡水商品鱼背、腹肉一般成分的季节变化

本文研究了鲢、鳙、草鱼、团头鲂、鲫背、腹肉蛋白质、脂肪等的季节变化及其有关营养、风味特点，发现5种鱼背肉脂肪含量12个月平均值均低于1％；蛋白质含量平均值在17．3—18．5％之间．不存在季节变化；是一种典型的高蛋白、低脂肪食物。反之，腹肉脂肪含量在2．2—9．7％之间．具有较多的脂肪和较好的风味。针对这种特点．鲢、鳙、草鱼等大型鱼采取背部、腹部分别加工是可取的。此外还测定证实鲢肌肉中含有较多的EPA和DHA。     

不同减菌方式对冰温贮藏草鱼片品质的影响

分别采用紫外线照射、臭氧杀菌和柠檬酸淋洗3种方式处理草鱼片,然后在冰温(-0.7℃)下贮藏,考察了3种处理方式对草鱼片总菌数、挥发性盐基氮(TVB-N)、硫代巴比妥酸(TBA)值、pH值、总酸度和感官质量的影响。结果表明:与对照组相比,3种处理方式均能抑制细菌生长,延缓蛋白质腐败,其中以臭氧杀菌处理效果最好。由蛋白质腐败指标TVB-N值到达一级鲜度预测草鱼片货架期,臭氧杀菌、柠檬酸淋洗和紫外线照射处理后的货架期分别为15、10和9d。     

Climate extremes: observations, modeling, and impacts

One of the major concerns with a potential change in climate is that an increase in extreme events will occur. Results of observational studies suggest that in many areas that have been analyzed, changes in total precipitation are amplified at the tails, and changes in some temperature extremes have been observed. Model output has been analyzed that shows changes in extreme events for future climates, such as increases in extreme high temperatures, decreases in extreme low temperatures, and increases in intense precipitation events. In addition, the societal infrastructure is becoming more sensitive to weather and climate extremes, which would be exacerbated by climate change. In wild plants and animals, climate-induced extinctions, distributional and phenological changes, and species' range shifts are being documented at an increasing rate. Several apparently gradual biological changes are linked to responses to extreme weather and climate events.     

没食子酸对恩诺沙星在鲤体内的药代动力学及残留的影响研究

为研究没食子酸与恩诺沙星联合用药及单用恩诺沙星在福瑞鲤Cyprinus carpio体内的药代动力学参数及其残留消除规律,采用平行对照试验,将体质量为(200±30)g的鲤随机分为单用恩诺沙星组(对照)和联合用药组(没食子酸与恩诺沙星质量比为10:1),试验水温为26℃,各组均按2 mg/kg(体质量)剂量的恩诺沙星单次混饲口灌给药,于给药后不同时间点采集鲤血浆、肌肉、肝胰脏、肾脏组织,采用高效液相色谱法测定各组织中恩诺沙星的浓度,并使用DAS 3.0药物代谢动力学软件的非房室模型统计矩方法分析药时数据。结果表明,没食子酸能显著增大鲤各组织对恩诺沙星的吸收效率,提高有效药物浓度20.0%~44.9%,并加快了恩诺沙星的代谢和消除,240 h时联合用药组鲤血浆、肌肉组织中药物残留量比对照组分别降低了44.2%和34.1%。     

氧含量急剧变化对冷血脊椎动物氧化压力的影响

氧气对大多生物体至关重要,但是氧气能转变为活性氧从而对机体产生毒性。多种冷血脊椎动物可耐受自然条件下产生的氧化压力,如某些鱼、蛙、龟和蛇等。综述了缺氧/低氧耐受性动物在环境、代谢产生供氧不足时的应对方式。对比这些动物的应对方式后发现了某些抗氧化能力提高的规律。机体一般采用关键抗氧化酶的酶活增强、谷胱甘肽含量增多来抵御氧化压力。     

有氧运动对小鼠心肌、骨骼肌线粒体SOD、MDA、LDH的影响

探讨了有氧运动对小鼠心肌、骨骼肌线粒体SOD、MDA、LDH的影响.结果表明,在3 h游泳运动后,试验组与对照组小鼠心肌中SOD的活性无显著差异(P>0.05),而骨骼肌中SOD活性显著降低(P<0.05);试验组小鼠心肌、骨骼肌线粒体中MDA的含量均有所升高,差异显著(P<0.05):LDH活性有所降低,但差异不显著(P>0.05).说明有氧运动对小鼠骨骼肌中SOD活性和小鼠心肌、骨骼肌线粒体中MDA含量的影响显著,但对LDH活性无显著影响.     

有氧发酵增温育苗对烤烟农艺性状和经济性状的影响

为解决南方烟区育苗时温度过低影响烟苗后期生长的问题,进行了在育苗池底部铺设有氧发酵材料(稻草秸秆、稻草秸秆+猪粪、稻草秸秆+花生麸)的增温育苗试验,对育苗池温度、烟苗生长状况和移栽后的大田农艺性状、干物质积累及产量产值等经济性状进行了测定.结果表明,有氧发酵增温育苗,尤其是稻草秸秆+花生麸处理,可以有效提高育苗池温度(...     

冷藏条件下鳙鱼阻抗特性与鲜度的关系

研究鳙鱼（Aristichthys nobilis）在冷藏（3℃）条件下鱼体阻抗特性及鱼片鲜度指标的变化。对鱼体相对阻抗变化率Q和鱼片鲜度指标（K值、w（TVB-N）、细菌总数及感官评分）进行测定,分析Q与K、w（TVB-N）、细菌总数和感官评分的相关性,建立其相关性模型。结果表明：鳙鱼鱼片在3℃贮藏至第12天感官评分为14,K值为74.1%;w（TVB-N）为16.1mg/100g;细菌总数1.30×105 CFU/g;鱼体Q降至12.7%,失去感官食用价值。Q与K、w（TVB-N）、细菌总数和感官评分的相关性系数r分别为0.993、0.971、0.977和0.981,达极显著水平,表明Q与各鲜度指标具有良好的相关性,在3℃贮藏条件下采用Q快速、无损伤地评估鳙鱼鱼片鲜度是可行的。     

夏秋季太湖4个控藻区鳙体内微囊藻毒素累积分析

为探讨微囊藻毒素(Microcystin,MCs)对水产品食用安全性的影响,于2015年6月向太湖4个控藻区(竺山湖、月亮湾、三国城、乌龟山)水体中投放规格约3 g/尾的鳙Aristichthys nobilis幼鱼,8—11月每月中旬从各控藻区固定采集鳙样本15尾,分别测定水体、鳙不同组织和器官中MCs的含量,并结合各控藻区的水质指标分析了MCs在鳙体内的累积规律及影响因子。结果表明:4个控藻区鳙不同组织和器官中总MCs含量依次为肌肉肝胰脏血清,且肌肉、肝胰脏中累积的总MCs极显著高于血清(P0.01);肌肉、肝胰脏和血清中MCs的累积在不同控藻区间均无显著性差异(P0.05);鳙肌肉、肝胰脏和血清中MCs的累积月份间有极显著性差异(P0.01);水温和藻类胞内MCs含量对血清、肝胰脏和肌肉中MCs的累积均有极显著影响(P0.01),体长对血清、肝胰脏中的MCs累积也有极显著影响(P0.01);蓝藻爆发期间,MCs含量较高,据世界卫生组织(WHO)建议的MC-LR日允许摄入量,4个湖区中每日人均可摄入鳙肉229.62~977.20 g,并不会给人类健康造成危害。本研究可为微囊藻毒素在鳙体内不同组织、器官的积累效应和水产品食用安全风险评估提供理论依据。     

五氯酚钠在鲫体内的毒性及代谢动力学的研究

在实验室条件下,研究了不同浓度的五氯酚钠溶液（0、1、2、3、4、5、10mg／L）对鲫Carassiusaurtlgt~的毒性作用,并采用药浴的方式研究了五氯酚钠在鲫体内不同时间段的药代谢动力学。结果表明：五氯酚钠对鲫的毒性作用很强,当药物浓度为10mg／L时,药浴1h后试验动物100％死亡;当药物浓度为2mg／L时,试验动物健康存活,药浴96h无死亡现象;将鲫在2mg／L的五氯酚钠溶液中浸浴24h后,药物迅速被鲫吸收,血浆中0．5h五氯酚钠浓度就能达到11．5ng／mL,1h达到峰值12．0ng／mL,但药物的代谢较慢,给药70d后才检测不到药物;药物在肌肉中的代谢与血浆中类似,1h达到峰值（11．84ng／mL）,比血浆中的峰浓度略低,药动学参数t1／2α、t1/2β,MRT0-1、Tmax、Cmax、AUC0-4和MAT分别为12．6h、186．8h、260．4h、1h、11．84ng／mL、1106．5ng／（mL·h）、222．5h。     

Fuel-powered artificial muscles

Artificial muscles and electric motors found in autonomous robots and prosthetic limbs are typically battery-powered, which severely restricts the duration of their performance and can necessitate long inactivity during battery recharge. To help solve these problems, we demonstrated two types of artificial muscles that convert the chemical energy of high-energy-density fuels to mechanical energy. The first type stores electrical charge and uses changes in stored charge for mechanical actuation. In contrast with electrically powered electrochemical muscles, only half of the actuator cycle is electrochemical. The second type of fuel-powered muscle provides a demonstrated actuator stroke and power density comparable to those of natural skeletal muscle and generated stresses that are over a hundred times higher.     

野生和养殖鲤鱼肌肉营养成分的比较研究

对野生和养殖鲤鱼肌肉常规营养成分、氨基酸含量和脂肪酸组成进行了测定和比较。常规营养成分测定结果表明,野生鲤鱼肌肉中粗蛋白含量显著高于养殖鲤鱼(P<0.01),而粗脂肪含量显著低于养殖鲤鱼(P<0.05)。氨基酸含量测定结果表明,野生鲤鱼氨基酸总量和必需氨基酸总量显著高于养殖鲤鱼(P<0.05),鲜味氨基酸总量差异不显著。脂肪酸组成测定结果表明,野生和养殖鲤鱼肌肉中均含有丰富的不饱和脂肪酸(UFA),分别占脂肪酸总量的95.63%和87.96%,野生和养殖鲤鱼肌肉脂肪酸组成有较大差异,野生鲤鱼肌肉中饱和脂肪酸(SFA)和单不饱和脂肪酸(MUFA)总量显著低于养殖鲤鱼(P<0.01);而多不饱和脂肪酸(PUFA)总量显著高于养殖鲤鱼(P<0.01)。同时,野生与养殖鲤鱼肌肉中n-3和n-6族多不饱和脂肪酸组成有较大差异,野生鲤鱼n-3和n-6族多不饱和脂肪酸总量均显著高于养殖鲤鱼(P<0.01),表明鲤鱼饲料配方中n-3和n-6族多不饱和脂肪酸的添加量可能不足。总的来说,野生鲤鱼肌肉的营养价值稍优于养殖鲤鱼。