How animals move: an integrative view

Recent advances in integrative studies of locomotion have revealed several general principles. Energy storage and exchange mechanisms discovered in walking and running bipeds apply to multilegged locomotion and even to flying and swimming. Nonpropulsive lateral forces can be sizable, but they may benefit stability, maneuverability, or other criteria that become apparent in natural environments. Locomotor control systems combine rapid mechanical preflexes with multimodal sensory feedback and feedforward commands. Muscles have a surprising variety of functions in locomotion, serving as motors, brakes, springs, and struts. Integrative approaches reveal not only how each component within a locomotor system operates but how they function as a collective whole.     

细菌鞭毛系统的研究进展

鞭毛是许多细菌用于推动自身运动的细胞器。运动能够帮助细菌趋向有利环境或躲避有害环境。鞭毛还在细菌底物吸附、生物膜形成和病原侵染过程中起着很重要的作用。因此,鞭毛对细菌的生存和与其他细菌的竞争至关重要。鞭毛的表达需要超过40个基因的参与,其合成和工作是一个非常耗能的过程,所以其基因的表达和组装是受到严格调控的。对鞭毛系统的研究有助于更深入地了解基因的表达调控机理,认识微生物对环境的适应性和应用仿生学制造机械马达等。该研究将重点关注于鞭毛系统的表达调控。     

稻田生态系统潜在生产力的探讨

采用半旱式自然免耕法种稻养鱼,产量达到了每公顷7500kg稻、750kg鱼,较好地发挥了稻田的生产潜力。试验结果表明,(1) 稻田水体生物可作鱼类食饵的类型繁多,各类稻田所处的生态环境不同,耕作水平有差异,鱼种及其规格必须合理搭配投放;(2) 稻、鱼长期共生,互有影响,必须加强养殖管理。     

Terrestrial and aquatic orientation in the starhead topminnow, fundulus notti

Starhead topminnows from various shores of a small woodland pond were displaced to unfamiliar surroundings, and their orientation was tested in aquatic and terrestrial arenas. These fish used a sun compass to move in a direction which, at the location of their capture, would have returned them to the land-water interface. The fish accomplished directional terrestrial locomotion by using the position of the sun to align its body for each jump. On heavily overcast days many fish were unable to orient their bodies in a consistent direction from, jump to jump; this inability to orient resulted in random rather than linear movement. There was considerable individual variation in terrestrial locomotor ability.     

洪湖养殖区水环境中微生物的耐药性及其群落功能多样性研究

为探讨抗生素对水产养殖环境微生物的影响,本研究通过采集洪湖养殖区地下水、湖水和鱼塘水,分别分析其细菌、真菌、放线菌数量及相应耐药(磺胺甲恶唑)微生物的分布规律,探讨耐药微生物数量及耐药微生物占比与磺胺抗生素浓度之间的相关性,并采用Biolog法研究不同水体中微生物群落功能多样性差异。结果表明,不同水体中微生物数量分布规律为:鱼塘水湖水地下水,而湖水和鱼塘水中的微生物数量受人为活动影响差异较大。三类水体均有不同程度耐药微生物检出,耐药微生物数量分布规律为:鱼塘水湖水地下水;耐药微生物占比分布规律为:湖水鱼塘水地下水。地下水中耐药微生物数量与磺胺抗生素浓度无显著相关性,而地表水中耐药细菌、耐药真菌数量及与磺胺吡啶和磺胺二甲基嘧啶浓度呈显著正相关;地表水中耐药细菌与耐药放线菌占比均与磺胺砒啶呈显著相关。Biolog多样性分析结果表明,地表水微生物群落代谢活性和碳源利用性均高于地下水,说明洪湖湖水和鱼塘水利用不同碳源的微生物物种较丰富。研究表明,不同环境水体中微生物的数量和耐药性以及群落功能多样性均有差异,该差异与人类活动和抗生素浓度有一定相关性。     

Fish population and behavior revealed by instantaneous continental shelf-scale imaging

Until now, continental shelf environments have been monitored with highly localized line-transect methods from slow-moving research vessels. These methods significantly undersample fish populations in time and space, leaving an incomplete and ambiguous record of abundance and behavior. We show that fish populations in continental shelf environments can be instantaneously imaged over thousands of square kilometers and continuously monitored by a remote sensing technique in which the ocean acts as an acoustic waveguide. The technique has revealed the instantaneous horizontal structural characteristics and volatile short-term behavior of very large fish shoals, containing tens of millions of fish and stretching for many kilometers.     

应用微机对常见鱼病自动诊断

本文根据鱼病学家,总结多年实践工作所积累的经验,充分利用计算机逻辑判断的特点,用微机对常见鱼病进行诊断的初步探索。在无专家帮助的条件下,一旦发生常见鱼病,本诊断程序有助于迅速地对发生的病情作出判断,尽快采取紧措施,以避免发病后造成重大的损失。     

A self-organized vortex array of hydrodynamically entrained sperm cells

Many patterns in biological systems depend on the exchange of chemical signals between cells. We report a spatiotemporal pattern mediated by hydrodynamic interactions. At planar surfaces, spermatozoa self-organized into dynamic vortices resembling quantized rotating waves. These vortices formed an array with local hexagonal order. Introducing an order parameter that quantifies cooperativity, we found that the array appeared only above a critical sperm density. Using a model, we estimated the hydrodynamic interaction force between spermatozoa to be approximately 0.03 piconewtons. Thus, large-scale coordination of cells can be regulated hydrodynamically, and chemical signals are not required.     

On the regulation of populations of mammals, birds, fish, and insects

A key unresolved question in population ecology concerns the relationship between a population's size and its growth rate. We estimated this relationship for 1780 time series of mammals, birds, fish, and insects. We found that rates of population growth are high at low population densities but, contrary to previous predictions, decline rapidly with increasing population size and then flatten out, for all four taxa. This produces a strongly concave relationship between a population's growth rate and its size. These findings have fundamental implications for our understanding of animals' lives, suggesting in particular that many animals in these taxa will be found living at densities above the carrying capacity of their environments.     

3种不同水源粪肠球菌耐药情况

为了解水环境中粪肠球菌对常用抗生素的耐药情况,从某校鱼塘、污水沟和模型池塘中共分离出99株粪肠球菌,采用美国临床实验室标准委员会(NCCLS)推荐的微量肉汤稀释法进行药敏试验.结果显示:污水沟分离菌的耐药率最高,其中红霉素、土霉素、环丙沙星、氯霉素和氨苄西林的耐药率分别为89.3%、89.3%、82.1%、46.4%和32.1%,且多数对3-5种抗生素多重耐药;其次为鱼塘分离菌,耐药谱多为对1-2种抗生素同时耐药;模型池塘分离敏感菌较多;3处均未分离出万古霉素耐药粪肠球菌.提示不同水源粪肠球菌耐药情况与水源受抗生素污染程度存在联系,表明细菌耐药性监测及环境保护的重要性.     

半夏不同溶剂提取物镇静催眠活性比较

[目的]研究比较半夏不同溶剂提取物的镇静、催眠作用。[方法]采用连续溶剂提取法制备半夏不同溶剂提取物,通过行为药理学试验,考察半夏不同溶剂提取物对小鼠自主活动和戊巴比妥诱导睡眠的影响。[结果]半夏浓度95%乙醇提取物和浓度60%乙醇提取物能显著抑制小鼠的自主活动;对戊巴比妥诱导的睡眠表现出协同作用,不仅显著增加了催眠剂量戊巴比妥小鼠的入睡只数,而且显著缩短了睡眠剂量戊巴比妥小鼠的入睡潜伏期,延长了其睡眠时间,具有明显的镇静、催眠作用。[结论]半夏醇提物为其镇静、催眠活性部位。     

尾部溃烂与健康的半滑舌鳎血液生理生化指标的比较

[目的]通过对比健康和尾部溃烂的半滑舌鳎血液生理生化指标,为该症状的治疗提供参考。[方法]测定血液红细胞数（RBC）、血沉（ESR）、比积（Ht）、白细胞吞噬活力,血清MDA含量、SOD活力、补体C3和C4含量、溶菌酶（LZM）活力、白蛋白/球蛋白（A/G）。[结果]2组半滑舌鳎的血液生理指标无显著差异（P〉0.05）,血液生化指标中MDA含量、SOD活力、补体C3含量、A/G和吞噬率差异显著（P〈0.05）,其他指标差异不显著（P〉0.05）。[结论]尾部溃烂的半滑舌鳎在血清MDA含量、SOD活力、补体C3含量、A/G和血液白细胞吞噬率等指标上与健康的半滑舌鳎有显著差异。     

贯流泵站(前池灯泡式)进口淹没深度的试验研究

本文通过观察同一水位下各种不同的流量及保持流量不变改变淹没深度时的流态、旋涡及吸气状况,研究了泵站进水口的旋涡特性及旋涡发生、发展的影响因素,得出了旋涡类型随淹没深度的变化规律,就后壁距等边界条件对临界淹没深度的影响进行了试验研究,並导出了临界淹没深度的经验公式。     

Observation of half-height magnetization steps in Sr2RuO4

Spin-triplet superfluids can support exotic objects, such as half-quantum vortices characterized by the nontrivial winding of the spin structure. We present cantilever magnetometry measurements performed on mesoscopic samples of Sr(2)RuO(4), a spin-triplet superconductor. With micrometer-sized annular-shaped samples, we observed transitions between integer fluxoid states as well as a regime characterized by "half-integer transitions"--steps in the magnetization with half the height of the ones we observed between integer fluxoid states. These half-height steps are consistent with the existence of half-quantum vortices in superconducting Sr(2)RuO(4).     

A fish from the upper cambrian of north america

Phosphatic dermal fragments of Anatolepis, interpreted as a heterostracan fish (class Agnatha), have been discovered in the Deadwood Formation of Late Cambrian age in northeastern Wyoming. This discovery extends back the age of the earliest known vertebrate fossils by approximately 40 million years. Other occurrences of Anatolepis in North America, Greenland, and Spitzbergen show that these fish had a widespread geographic distribution in Late Cambrian and Early Ordovician marine environments.     

鲟鱼消化生理和营养需求研究进展

鲟鱼是一类古老的鱼类,其消化系统具有较为原始的特征,其消化生理也有特异性。鲟鱼消化酶的种类组成与活性及其在发育过程中的变化模式与食性密切相关。鲟鱼属于偏肉食性鱼类,对饲料蛋白质的需求量较高。鲟鱼对脂肪和糖类的消化能力较强,能够利用高水平的脂肪和糖类。     

Aluminum leaching response to Acid precipitation: effects on high-elevation watersheds in the northeast

Atmospheric inputs of sulfuric acid and nitric acid to noncalcareous higher-elevation watersheds in the White Mountain and Adirondack regions lead to comparatively high concentrations of dissolved aluminum in surface and ground waters. This phenomenon appears to result from modern increases in soil aluminum leaching. Transport of this aluminum to acidified lakes can lead to fish mortality. Combined results from areas of silicate bedrock in the United States and Europe suggest that aluminum represents an important biogeochemical linkage between terrestrial and aquatic environments exposed to acid precipitation.     

A superconducting reversible rectifier that controls the motion of magnetic flux quanta

We fabricated a device that controls the motion of flux quanta in a niobium superconducting film grown on an array of nanoscale triangular pinning potentials. The controllable rectification of the vortex motion is due to the asymmetry of the fabricated magnetic pinning centers. The reversal in the direction of the vortex flow is explained by the interaction between the vortices trapped on the magnetic nanostructures and the interstitial vortices. The applied magnetic field and input current strength can tune both the polarity and magnitude of the rectified vortex flow. Our ratchet system is explained and modeled theoretically, taking the interactions between particles into consideration.     

2种虫源性蛋白替代鱼粉对黄颡鱼幼鱼生长、体成分和蛋白酶活性的影响

以鱼粉作为对照,用黄粉虫、蚕蛹干粉半量和全量替代鱼粉,配制5组等蛋白质水平(40%)的饲料,对黄颡鱼幼鱼进行36 d的饲养.结果表明:对照组幼鱼的增重率、蛋白质消化率和饵料系数显著高于其他组(P0.05),黄粉虫和蚕蛹全量替代组的增重率显著低于半量替代组(P0.05);全黄粉虫组幼鱼的蛋白质消化率与2种半量替代组间的差异不显著(P0.05),而蚕蛹组的蛋白质消化率显著低于其他替代组;除半量黄粉虫组幼鱼的饵料系数与对照组间的差异不显著外,全量替代组和半量蚕蛹组的饵料系数均显著高于对照组(P0.05);除机体含水率外,各替代组幼鱼机体的粗蛋白含量只有全蚕蛹组显著低于其他组(P0.05),而全蚕蛹组和半量蚕蛹组幼鱼的粗脂肪含量显著高于其他组(P0.05);除半量黄粉虫组幼鱼的粗灰分含量与对照组间的差异不显著(P0.05)外,其他3组间的差异显著(P0.05);对照组幼鱼肝胰脏、胃、肠道的蛋白酶活性均最高,除胃蛋白酶活性与半量黄粉虫组间的差异显著外(P0.05),肝胰脏和肠道的蛋白酶活性与半量黄粉虫组间的差异均不显著(P0.05),但显著高于2种全量替代组(P0.05).     

枯草芽孢杆菌发酵鱼粉产蛋白酶及其酶解效果

为开发以鱼粉为原料的优质饲料蛋白源以及相关保健食品,开展了用不同鱼粉为氮源发酵枯草芽孢杆菌生产蛋白酶及其酶解效果的研究,比较了不同菌种的发酵效果,确定了最佳发酵时间.通过蛋白酶活性测定和氨基态氮含量测定分析了不同菌种的产酶能力和酶活性大小及其酶解效果.结果表明,用罗非鱼鱼粉和处理过的鳕鱼鱼粉发酵商业化的工业菌种枯草芽孢杆菌产生的酶活性显著高于鲢鱼鱼粉（P〈0.05）,发酵后上清液中的氨基态氮含量也显著高于鲢鱼鱼粉（P〈0.05）,即工业化的枯草芽孢杆菌对不同鱼粉的发酵效果不同,罗非鱼鱼粉和处理过的鳕鱼鱼粉发酵效果显著优于鲢鱼鱼粉.