Flight physiology of migrating Urania fulgens (Uraniidae) moths: kinematics and aerodynamics of natural free flight

Summary Air speeds and wing kinematics were determined for the Neotropical moth Urania fulgens in natural migratory flight over Lake Gatun, Republic of Panama. Morphological parameters are presented for the same insects filmed in free flight. A quasi-steady aerodynamic analysis was used to show that unsteady mechanisms of lift generation are probably not necessary to produce the forces necessary for fast forward flight. Mechanical power requirements of forward flight were estimated from the biomechanical and morphological data. Over an airspeed range of 1.5 to 4.5 m/s, the mechanical power required to fly is predicted to increase dramatically with forward speed. A comparison of estimated metabolic rates with endogenous lipid reserves suggests that U. fulgens feeds extensively on flower nectar during migration from Central into South America.     

Aerial performance of stalk-eyed flies that differ in eye span

Stalk-eyed flies have eyes placed laterally away from the head on elongated peduncles. The elongation of eye span may increase the energetic cost of flight, reduce flight performance via aerodynamic effects or via increased load, or necessitate compensatory changes in other body dimensions. Body mass and body dimensions were measured to test the hypothesis that elongation of eye span is correlated with increased head mass in two closely related species of stalk-eyed flies. Cyrtodiopsis whitei is sexually dimorphic, with the eye span of larger males exceeding body length. Cyrtodiopsis quinqueguttata is sexually monomorphic with eye span substantially less than body length. Although eye span was significantly longer in C. whitei, head mass did not differ between species after accounting for differences in body mass. C. whitei males had longer wings, heavier thoraxes, and lighter abdomens in relation to body mass than did female C. whitei or C. quinqueguttata of either sex. Three-dimensional tracking of flight paths showed that path velocity and the horizontal component of velocity did not differ according to species or sex, but the long-eyed C. whitei males showed reduced overall aerial performance by flying at shallower ascent angles and reduced vertical velocity. Although increased mass loading does not occur in C. whitei males, increased drag, aerodynamic effects from the wake of the eye stalks, and constrained visual processing are possible mechanisms which could cause their reduced performance. Accepted: 7 June 2000     

鸟类的飞翔

本文综述了目前对鸟类飞翔的研究 ,包括飞翔机制、运动学和形态适应等问题。首先讨论动力产生的基础包括翼型运动和气体旋涡以及飞翔需要的动力 ,而后论述振翅飞翔和姿势变换的运动学原理及量化飞翔强度 ,阐明了翼部和尾部外形对飞翔的重要作用 ,并分析了始祖鸟的飞翔能力     

Optimal flight initiation distance

Decisions regarding flight initiation distance have received scant theoretical attention. A graphical model by Ydenberg and Dill (1986. The economics of fleeing from predators. Adv. Stud. Behav. 16, 229-249) that has guided research for the past 20 years specifies when escape begins. In the model, a prey detects a predator, monitors its approach until costs of escape and of remaining are equal, and then flees. The distance between predator and prey when escape is initiated (approach distance = flight initiation distance) occurs where decreasing cost of remaining and increasing cost of fleeing intersect. We argue that prey fleeing as predicted cannot maximize fitness because the best prey can do is break even during an encounter. We develop two optimality models, one applying when all expected future contribution to fitness (residual reproductive value) is lost if the prey dies, the other when any fitness gained (increase in expected RRV) during the encounter is retained after death. Both models predict optimal flight initiation distance from initial expected fitness, benefits obtainable during encounters, costs of escaping, and probability of being killed. Predictions match extensively verified predictions of Ydenberg and Dill's (1986) model. Our main conclusion is that optimality models are preferable to break-even models because they permit fitness maximization, offer many new testable predictions, and allow assessment of prey decisions in many naturally occurring situations through modification of benefit, escape cost, and risk functions.     

谷氨酸菌体破碎条件的优化研究

以释放胞内物质为主要目的的细胞破碎条件,采用均质破碎法、超声波法、加酶法和碱性自溶法等对谷氨酸菌作进行破碎试验,并对其相应的工艺参数进行了优化研究。结果表明,使用碱性自溶法在pH10.0,温度70℃,干菌浓度为10％时,自溶40min后蛋白质的释放率接近80％,表明该法对释放胞内物质的作用效果较理想。     

Optimal viral immune surveillance evasion strategies

Following cell entry, viruses can be detected by cytotoxic T lymphocytes. These cytotoxic T lymphocytes can induce host cell apoptosis and prevent the propagation of the virus. Viruses with fewer epitopes have a higher survival probability, and are selected through evolution. However, mutations have a fitness cost and on evolutionary periods viruses maintain some epitopes. The number of epitopes in each viral protein is a balance between the selective advantage of having fewer epitopes and the reduced fitness following the epitope removing mutations. We discuss a bioinformatic analysis of the number of epitopes in various viral proteins and propose an optimization framework to explain these numbers. We show, using a genomic analysis and a theoretical optimization framework, that a critical factor affecting the number of presented epitopes is the expression stage in the viral life cycle of the gene coding for the protein. The early expression of epitopes can lead to the destruction of the host cell before budding can take place. We show that a lower number of epitopes is expected in early proteins even if late proteins have a much higher copy number.     

广义Logistic模型的捕获优化问题

以王寿松所提出的广义Ｌｏｇｉｓｔｉｃ模型为基础,讨论单种群生物资源的捕获优化问题,分析了被开发生物种群的动力学性质。在单位捕获努力量假定下,以最大可持续捕获量为管理目标,确定了线性捕获下的最优捕获策略,得到了最优捕获努力量,最大可持续收获及相应的最优种群水平的显式表达式,包括著名的Ｓｃｈａｅｆｅｒ模型作为特例,推广了相应的结果。     

Optimal coordination and control of posture and movements

This paper presents a theoretical model of stability and coordination of posture and locomotion, together with algorithms for continuous-time quadratic optimization of motion control. Explicit solutions to the Hamilton–Jacobi equation for optimal control of rigid-body motion are obtained by solving an algebraic matrix equation. The stability is investigated with Lyapunov function theory and it is shown that global asymptotic stability holds. It is also shown how optimal control and adaptive control may act in concert in the case of unknown or uncertain system parameters. The solution describes motion strategies of minimum effort and variance. The proposed optimal control is formulated to be suitable as a posture and movement model for experimental validation and verification. The combination of adaptive and optimal control makes this algorithm a candidate for coordination and control of functional neuromuscular stimulation as well as of prostheses. Validation examples with experimental data are provided.     

对蜱致病性球孢白僵菌培养条件的优化

对前期筛选得到的具有生防潜力的杀蜱真菌Beauveria bassiana AT17菌株进行相关生物学性状的研究,建立一套规范的实验室培养的技术和方法,同时对其液固双相发酵技术进行优化,在于提供优质高效的生防材料,为其真菌制剂的规模化生产提供实践和理论基础。通过采用单因素筛选方案对其最适基础培养基、温度、pH值、碳源、氮源、微量元素及液固双相发酵配方进行研究,发现该菌株在PDA、PPDA、PDAY、SDAY、SMAY 5种培养基上均能较好生长,在PDA上生长最快,在PDAY上产孢量最大。温度对菌丝的生长和产孢影响显著,25°C菌丝生长最快,且产孢量最大。B.bassiana AT17菌株在pH 4-10范围内均可生长,在偏碱性环境内生长最快,在pH 5-6的偏酸性环境内产孢量最大。综合评价真菌各项指标后,葡萄糖和酵母粉为菌丝生长和产孢的最佳碳源和氮源,固体物料麦麸+玉米粉+米粉与基础培养液3/4 SDAY按2:1均匀混合后,添加0.05%K+可作为菌株固体发酵的最佳物料配方组合。     

产壳聚糖酶菌株的发酵条件优化

方法:通过单因子实验,对保存的1株产壳聚糖酶的菌株C001进行发酵产酶条件优化,确定了最适产酶培养基组分.结果:温度30℃,发酵时间18h,pH5.5,接种量5%优化发酵条件后,产壳聚糖酶活力增长了37.4%.     

沼泽红假单胞菌J001产辅酶Q10摇瓶发酵条件优化

本试验对沼泽红假单胞菌J001菌株250ml摇瓶发酵辅酶Q10条件进行了优化。结果表明其最佳初始pH值为6.5-7.5,温度为28-31℃,摇床转速100 r min-1,摇瓶装液量为200ml,接种量达10%时可直接进入对数生长期;碳源以NaAc较好,氮源以(NH4)2SO4和NH4Cl较好,磷源用量对考察指标影响不明显;用中心组合设计响应曲面法对碳氮源用量进行了优化,当NaAc浓度为5.39（g l-1）,(NH4)2SO4浓度为0.385（g l-1）即碳氮比为14/1时,对菌胞生长最有利;当NaAc浓度为5.70（g l-1）,(NH4)2SO4浓度为0.365（g l-1）即碳氮比为15.6/1时,对辅酶Q10产量最有利。     

产几丁质酶菌株SWCH-6的筛选、鉴定及其产酶条件的优化研究

从汕头海湾养殖区域的海底沉积物中分离到1株几丁质酶活性较高的菌株, 命名为SWCH-6, 根据菌株的形态特征、生理生化特征和16S rDNA 序列, 确定该菌株为嗜水气单胞菌(Aeromonas hydrophlilla)。采用单因素优化方法结合正交实验, 得到菌株SWCH-6产几丁质酶的最佳发酵条件：胶体几丁质25.0 g/L, 胰蛋白胨10.0 g/L, 陈海水1.0 L, pH 8.5, 32℃, 150 r/min培养72 h; 在该条件下酶活力达0.39 U/mL。此外, 菌株所产几丁质酶的最适催化pH 5.0; 最适催化温度为40℃; Cu2+、Fe3+及表面活性剂Tween-80能增强该酶的催化活性; Zn2+、Mn2+及表面活性剂SDS、洗衣粉对该酶的催化活性有抑制作用, 与其它几丁质酶存在着一些不同。     

产几丁质酶菌株SWCH-6的筛选、鉴定及其产酶条件的优化研究

从汕头海湾养殖区域的海底沉积物中分离到1株几丁质酶活性较高的菌株,命名为SWCH-6,根据菌株的形态特征、生理生化特征和16S Rdna序列,确定该菌株为嗜水气单胞茵(Aeromonas hydrophlilla).采用单因素优化方法结合正交实验,得到菌株SWCH-6产几丁质酶的最佳发酵条件:胶体几丁质25.0g/L,胰蛋白胨10.0g/L,陈海水1.0L, Ph 8.5,32℃,150 r/min培养72h;在该条件下酶活力达0.39U/Ml.此外,菌株所产几丁质酶的最适催化Ph 5.0;最适催化温度为40℃;Cu2、Fe3及表面活性剂Tween-80能增强该酶的催化活性;Zn2 、Mn2 及表面活性剂SDS、洗衣粉对该酶的催化活性有抑制作用,与其它几丁质酶存在着一些不同.     

Optimal biocatalyst loading in a fixed bed

The optimal distribution of biocatalyst in a fixed bed operating at steady state was determined to minimize the length of the bed for a fixed conversion of 95%. The distribution in terms of the biocatalyst loading on an inert support depends upon the axial distance from the bed entrance (continuous solution) as well as a set of dimensionless parameters that reflect the bed geometry, the bulk flow, reaction kinetics and diffusional characteristics. A mathematical model of the system with the following features was used to obtain the results: (1) convective mass transfer and dispersion in the bulk phase; (2) mass transfer from the bulk phase to the surface of the catalyst particle; and (3) simultaneous diffusion and chemical reaction in the catalyst particle with Michaelis–Menton kinetics and a reliable diffusion model (Zhao and DeLancey in Biotechnol Bioeng 64:434–441, 1999, 2000). The solution to the mathematical model was obtained with Mathematica utilizing the Runge Kutta 4–5 method. The dimensionless length resulting from the continuous solution was compared with the optimal length restricted to a uniform or constant cell loading across the entire bed. The maximum difference in the dimensionless length between the continuous and uniform solutions was determined to be 6.5%. The model was applied to published conversion data for the continuous production of ethanol that included cell loading (Taylor et al. in Biotechnol Prog 15:740–751, 2002). The data indicated a minimum production cost at a catalyst loading within 10% of the optimum predicted by the mathematical model. The production rate versus cell loading in most cases displayed a sufficiently broad optimum that the same (non-optimal) rate could be obtained at a significantly smaller loading such as a rate at 80% loading being equal to the rate at 20% loading. These results are particularly important because of the renewed interest in ethanol production (Novozymes and BBI International, Fuel ethanol: a technological evolution, 2004).     

亲本对后代群体的不均等遗传贡献及其优化控制

由于自然选择和人工选择的共同作用,使不同亲本的基因在后代基因库中所占比例有所不同,即亲本对后代群体的不均等遗传贡献。本文分析表明,不均等遗传贡献通过实现选择差和群体有效含量对遗传进展产生影响,并使传统的预估选择反应公式出现误差。育种的目标首先是找出在遗传上真正优秀的个体,同时还应当使越优秀的个体对后代基因库的遗传贡献越大。但后一方面尚未得到系统的研究。本文针对这一点,提出了以加快群体遗传进展为总目标、充分考虑育种约束条件的优化控制遗传贡献率的方法。对蛋鸡育种实际资料的计算结果表明,在同等群体含量水平下,优化不均等遗传贡献模式下所获得的实现选择差可比实际值提高34.27—216.57%。     

年龄相关的种群系统的最优生育率控制

讨论了一类与年龄相关的时变种群系统最优生育率控制的非线性问题,利用Ba- nach空间的Saks-Masur引理,证明了系统最优生育率控制的存在唯一性,并得到了控制为最优的必要条件和最优性组．所得结果可为种群系统控制问题的实际研究提供必要的数学理论基础．     

重组中华仓鼠卵巢细胞培养过程控制的研究进展

中华仓鼠卵巢细胞(Chinese Hamster Ovary Cells,CHO)是科研及生产中用于蛋白表达的常用体系。与大肠杆菌相比,CHO获得高表达的细胞株所需时间更长,蛋白产量更低。因此,大规模培养细胞所需的成本较高,培养条件也不易掌握。但该体系产生的蛋白纯度高,因而被广泛用于工业生产中。本文对CHO细胞的培养方式、pH值测定、渗透压、溶氧及培养液成分的选择等多方面条件进行综述,为优化中华仓鼠卵巢细胞培养的策略及具体方法提供理论依据。     

重组巴斯德毕赤酵母发酵生产几丁质酶的条件优化研究

研究了利用重组巴斯德毕赤酵母诱导表达重组几丁质酶的条件。在摇瓶水平上研究了诱导时间、pH、甲醇流加量、油酸等因素对重组几丁质酶表达的影响。结果发现诱导108h蛋白表达量最高;偏酸性环境不利于蛋白表达,维持在pH5.5～6.0最佳;甲醇最佳诱导浓度为1%;添加0.05%的油酸有助于提高蛋白表达量。在此基础上通过正交试验设计优化了培养基配方,在优化条件下,蛋白表达量达171.99mg/L,酶活达49.58U/mL。     

优化重叠PCR法进行单链抗体基因扩增和点突变

利用重叠PCR技术扩增单链抗体基因或位点突变是抗体文库构建或稳定表达的关键和难点,国内外文献未见其方法学的系统报道.以不同VH、VL和Linker基因为拼接模板进行重叠PCR,针对影响重叠PCR扩增的拼接类型,引物设计,反应条件等进行优化.结果表明两段重叠连接比三段更容易实现,且扩增效果好;引物的互补序列长度一般应大于15 bp,且在18～24 bp 时扩增效果最好;退火温度在52～60℃,Mg2+浓度在1.5～2.5 mM时对拼接的效果影响较小;直接或间接使用拼接模板均可以实现重叠PCR的扩增.利用优化策略,首次构建了抗除虫菊酯的scFv基因文库并引入抗XAC糖蛋白scFv基因的点突变,为除虫菊酯抗体文库构建和抗XAC重组抗体的稳定表达奠定了基础.     

Optimal escape theory predicts escape behaviors beyond flight initiation distance： risk assessment and escape by striped plateau lizards Sceloporus virgatus

Escape theory predicts that flight initiation distance (FID=distance between predator and prey when escape begins) is longer when risk is greater and shorter when escape is more costly. A few tests suggest that escape theory applies to distance fled. Escape models have not addressed stochastic variables, such as probability of fleeing and of entering refuge, but their economic logic might be applicable. Experiments on several risk factors in the lizard Sceloporus virgatus confirmed all predictions for the above escape variables. FID was greater when approach was faster and more direct, for lizards on ground than on trees, for lizards rarely exposed to humans, for the second of two approaches, and when the predator turned toward lizards rather than away. Lizards fled further during rapid and second consecutive approaches. They were more likely to flee when approached directly, when a predator turned toward them, and during second approaches. They were more likely to enter refuge when approached rapidly. A novel finding is that perch height in trees was unrelated to FID because lizards escaped by moving out of sight, then moving up or down unpredictably. These findings add to a growing body of evidence supporting predictions of escape theory for FID and distance fled. They show that two probabilistic aspects of escape are predictable based on relative predation risk levels. Because individuals differ in boldness, the assessed optimal FID and threshold risks for fleeing and entering refuge are exceeded for an increasing proportion of individuals as risk increases[Current Zoology 55(2):123-131,2009].