内蒙古天然草原不同放牧压力下亚洲小车蝗的食性及营养生态位（英文）

植物表皮蜡质中的饱和链烷作为内源指示剂广泛用于评价放牧家畜的食性和食量, 但用于天然草原蝗虫食性的评价研究较少。为了探讨天然草原蝗虫的食性及其生态位变化, 本研究以内蒙古天然草原为研究对象, 于2003年7-8月沿降水梯度选择3种典型植物群落（小针茅Stipa klemenzii、 羊草Leymus chinensis和大针茅Stipa grandis群落）, 在每个植物群落不同放牧压力下小区随机做20个植被样方, 样方内植物齐地面刈割, 测定其地上生物量和物种多样性, 取主要植物种测定其链烷模式, 同时采集放牧小区优势蝗虫种亚洲小车蝗Oedaleus asiaticus的粪便, 测定其链烷模式, 运用链烷技术评价蝗虫的食性及其营养生态位。结果表明： 不同植物群落中优势牧草种类及其比例不同, 其链烷模式存在种间差异, 链烷技术可以评价亚洲小车蝗的食性。亚洲小车蝗的食性在不同植物群落及不同放牧压力下存在显著的差异, 在羊草和大针茅群落中, 亚洲小车蝗是禾草采食者, 主要采食羊草和糙隐子草Cleistogenes squarrosa, 且与绵羊的营养生态位重叠指数较低, 分别为0.0619和0.0172; 在小针茅群落中亚洲小车蝗是杂类草采食者, 主要采食无芒隐子草Cleistogenes songorica、 猪毛菜Salsola collina和小针茅, 且与绵羊的营养生态位重叠指数较高, 达到0.1815。因此, 放牧不仅改变了群落的植物种类组成, 而且直接影响了亚洲小车蝗的食物组成, 二者对食物资源利用存在一定程度的竞争。     

360度群体遗传变异扫描——大豆泛基因组研究

大豆(Glycine max)是重要的油料和蛋白作物, 其丰富的遗传变异为生物学性状挖掘和育种改良提供了重要的资源基础。然而, 单个基因组信息无法全面揭示种质资源的遗传变异, 泛基因组研究为解决这一不足提供了新方案。近日, 中国科学院遗传与发育生物学研究所田志喜和梁承志研究团队从2 898份大豆种质中选取26份代表性材料, 并整合已有的3个基因组, 构建了包含野生和栽培大豆的泛基因组和图基因组(graph-based genome), 鉴定了整个群体的绝大多数结构变异数据集, 确定了大豆种质的核心、非必需和个体特异的基因集。利用这些数据系统地揭示了生育期位点E3的等位基因变异和基因融合事件、种皮颜色基因I的单体型和演化关系以及结构变异对铁离子转运基因表达和地区适应性选择的影响。该研究为作物基因组学研究提供了一个新的模式, 同时将加速推动大豆遗传变异的鉴定、性状解析和种质创新。     

Algal Population Growth Model Integrated with Toxicokinetics for Ecological Risk Assessment under Time-Varying Pesticide Exposure

An algal population growth model integrated with toxicokinetics was developed for assessing the effect of pesticides on population dynamics. This model is a simple one-compartment, first-order kinetic model in which toxicity (growth inhibition and mortality) depends on the intracellular effective concentration of a pesticide at a target site. The model's parameters were derived using an experimental study that investigated the effects of pretilachlor, bensulfuron-methyl, pentoxazone, and quinoclamine on the growth, mortality, and subsequent population recovery of the green alga Pseudokirchneriella subcapitata. Modeled and measured trajectories of algal population dynamics agreed well. The effect on population recovery was underestimated by the model that ignored the toxicokinetics. The four tested herbicides had a variety of toxicity characteristics and physicochemical properties, indicating the wide range of the model's applicability. Moreover, the developed model and the obtained model's parameters were extrapolated to predict long-term algal population dynamics under time-varying herbicide exposure. The calculated integral biomass lost compared with the control was considered a quantitative index of the population-level ecological risk. The model's prediction showed that the same exposure level (peak concentration is equivalent to EC50) indicated much different population-level effect depending on the herbicide.     

Mark‐resight abundance and survival estimation of Indo‐Pacific bottlenose dolphins,Tursiops aduncus,in the Swatch‐of‐No‐Ground,Bangladesh

A mark‐resight analysis under Pollock's robust design was applied to Indo‐Pacific bottlenose dolphins Tursiops aduncus in the Swatch‐of‐No‐Ground (SoNG) submarine canyon, Bangladesh, during the winter seasons of 2005–2009. Information from sightings of photo‐identified individuals (1,144) and unmarked individuals generated abundance estimates of 1,701 (95% confidence interval [CI]= 1,533–1,888), 1,927 (95% CI = 1,851–2,006), 2,150 (95% CI = 1,906–2,425), and 2,239 (95% CI = 1,985–2,524) individuals for seasons 1–4, respectively. This makes the population among the largest assessed of the species. Overall apparent survival was estimated as 0.958 (95% CI = 0.802–0.992). Interseasonal probabilities of transitioning to an unobservable state were estimated as 0.045, 0.363, and 0.300 for years 1–2, 2–3, and 3–4, respectively, and the overall probability of remaining in an unobservable state was 0.688. These probabilities, together with an apparent increase in abundance during the study period, indicate that the identified dolphins are part of a larger superpopulation moving throughout a more extensive geographic area. Of the photo‐identified dolphins, 28.2% exhibited injuries related to entanglements with fishing gear. This implies a strong potential for fatal interactions that could jeopardize the conservation status of the population, which otherwise appears favorable.     

Canalization and developmental instability of the fetal skull in a mouse model of maternal nutritional stress

Nutritional imbalance is one of the main sources of stress in both extant and extinct human populations. Restricted availability of nutrients is thought to disrupt the buffering mechanisms that contribute to developmental stability and canalization, resulting in increased levels of fluctuating asymmetry (FA) and phenotypic variance among individuals. However, the literature is contradictory in this regard. This study assesses the effect of prenatal nutritional stress on FA and among‐individual variance in cranial shape and size using a mouse model of maternal protein restriction. Two sets of landmark coordinates were digitized in three dimensions from skulls of control and protein restricted specimens at E17.5 and E18.5. We found that, by the end of gestation, maternal protein restriction resulted in a significant reduction of skull size. Fluctuating asymmetry in size and shape exceeded the amount of measurement error in all groups, but no significant differences in the magnitude of FA were found between treatments. Conversely, the pattern of shape asymmetry was affected by the environmental perturbation since the angles between the first eigenvectors extracted from the covariance matrix of shape asymmetric component of protein restricted and control groups were not significantly different from the expected for random vectors. In addition, among‐individual variance in cranial shape was significantly higher in the protein restricted than the control group at E18.5. Overall, the results obtained from a controlled experiment do not support the view of fluctuating asymmetry of cranial structures as a reliable index for inferring nutritional stress in human populations. Am J Phys Anthropol 154:544–553, 2014. © 2014 Wiley Periodicals, Inc.     

Kolmogorov-type competition model with finitely supported allocation profiles and its applications to plant competition for sunlight

A Kolmogorov-type competition model featuring allocation profiles, gain functions, and cost parameters is examined. For plant species that compete for sunlight according to the canopy partitioning model [R.R. Vance and A.L. Nevai, Plant population growth and competition in a light gradient: a mathematical model of canopy partitioning, J. Theor. Biol. 245 (2007), pp. 210–219] the allocation profiles describe vertical leaf placement, the gain functions represent rates of leaf photosynthesis at different heights, and the cost parameters signify the energetic expense of maintaining tall stems necessary for gaining a competitive advantage in the light gradient. The allocation profiles studied here, being supported on three alternating intervals, determine “interior” and “exterior” species. When the allocation profile of the interior species is a delta function (a big leaf) then either competitive exclusion or coexistence at a single globally attracting equilibrium point occurs. However, if the allocation profile of the interior species is piecewise continuous or a weighted sum of delta functions (multiple big leaves) then multiple coexistence states may also occur.     

Feeding dynamics of Palaemon peringueyi (Decapoda,Caridea) in the temporarily open/closed Kasouga Estuary,South Africa

The feeding ecology of the caridean shrimp Palaemon peringueyi in the temporarily open/closed Kasouga Estuary, Eastern Cape, was examined during summer and winter employing stomach fullness index (SFI) analysis. Mean SFI values for male and female shrimp during summer ranged from 0.85% to 2.36% and from 0.56% and 2.61% body dry weight, respectively. During winter, SFI values for males and females were lower, and varied between 0.23% and 1.56% and 0.36% and 1.84% body dry weight, respectively. There were no significant differences in the SFI values between males and females during the two seasons. A peak in the feeding activity for both sexes was observed during the daytime during both summer and winter. For both males and females, non-linear regression analysis best explained the change in SFI over time. The gut evacuation rate constants (k) of males and females during summer were estimated at 0.43 h^?1 and 0.30 h^?1, respectively. These values correspond to a daily food intake equivalent to 16.2% body dwt for males and 11.1% body dwt for females. During winter, the gut evacuation rates of the shrimp were estimated at 0.35 h^?1 for males and 0.28 h^?1 for females. The daily ration for adult male and female shrimp during winter was estimated at 6.1% and 6.8% body dwt, respectively. The lower estimates obtained during winter appear largely to reflect the influence of the reduced water temperatures on the metabolic activities of the shrimp.     

Atypical expression of circadian clock genes in denervated mouse skeletal muscle

Muscle force production and power output in active males, regardless of the site of measurement (hand, leg, or back), are higher in the evening than in the morning. This diurnal variation is attributed to motivational, peripheral and central factors, and higher core and, possibly, muscle temperatures in the evening. This study investigated whether increasing morning rectal temperatures to evening resting values, by active or passive warm-ups, leads to muscle force production and power output becoming equal to evening values in motivated subjects. Ten healthy active males (mean ± SD: age, 21.2 ± 1.9 yrs; body mass, 75.4 ± 8 kg; height, 1.76 ± .06 m) completed the study, which was approved by the University Ethics Committee. The subjects were familiarized with the techniques and protocol and then completed four sessions (separated by at least 48 h): control morning (07:30 h) and evening (17:30 h) sessions (with an active 5-min warm-up) and then two further sessions at 07:30 h but proceeded by an extended active or passive warm-up to raise rectal temperature to evening values. These last two sessions were counterbalanced in order of administration. During each trial, three measures of handgrip strength, isokinetic leg strength measurements (of knee flexion and extension at 1.05 and 4.19 rad.s^?1 through a 90° range of motion), and four measures of maximal voluntary contraction (MVC) on an isometric ergometer (utilizing the twitch-interpolation technique) were performed. Rectal and intra-aural temperatures, ratings of perceived exertion (RPE) and thermal comfort (TC) were measured. Measurements were made after the subjects had reclined for 30 min and after the warm-ups and prior to the measurement of handgrip and isokinetic and isometric ergometry. Muscle temperature was taken after the warm-up and immediately before the isokinetic and MVC measurements. Warm-ups were either active (cycle ergometer at 150 W) or passive (resting in a room at 35°C, relative humidity 45%). Data were analyzed using analysis of variance models with repeated measures. Rectal and intra-aural temperatures were higher at rest in the evening (.56°C and .74°C; p < .05) than in the morning, but there were no differences after the active or passive warm-ups, the subjects' ratings of thermal comfort reflecting this. Muscle temperatures also displayed significant diurnal variation, with higher values in the evening (～.31°C; p < .05). Grip strength, isokinetic knee flexion for peak torque and peak power at 1.05 rad.s^?1, and knee extension for peak torque at 4.19 rad.s^?1 all showed higher values in the evening. All other measures of strength or power showed a trend to be higher in the evening ( .10 > p > .05). There was no significant effect of active or passive warm-ups on any strength or power variable, and subjects reported maximal values for effort for each strength measure. In summary, effects of time of day were seen in some measures of muscle performance but, in this population of motivated subjects, there was no evidence that increasing morning rectal temperature to evening values by active or passive warm-up increased muscle strength to evening values. (Author correspondence: B.J.Edwards@ljmu.ac.uk)     

An improved OpenSim gait model with multiple degrees of freedom knee joint and knee ligaments

Musculoskeletal models are widely used to investigate joint kinematics and predict muscle force during gait. However, the knee is usually simplified as a one degree of freedom joint and knee ligaments are neglected. The aim of this study was to develop an OpenSim gait model with enhanced knee structures. The knee joint in this study included three rotations and three translations. The three knee rotations and mediolateral translation were independent, with proximodistal and anteroposterior translations occurring as a function of knee flexion/extension. Ten elastic elements described the geometrical and mechanical properties of the anterior and posterior cruciate ligaments (ACL and PCL), and the medial and lateral collateral ligaments (MCL and LCL). The three independent knee rotations were evaluated using OpenSim to observe ligament function. The results showed that the anterior and posterior bundles of ACL and PCL (aACL, pACL and aPCL, pPCL) intersected during knee flexion. The aACL and pACL mainly provided force during knee flexion and adduction, respectively. The aPCL was slack throughout the range of three knee rotations; however, the pPCL was utilised for knee abduction and internal rotation. The LCL was employed for knee adduction and rotation, but was slack beyond 20° of knee flexion. The MCL bundles were mainly used during knee adduction and external rotation. All these results suggest that the functions of knee ligaments in this model approximated the behaviour of the physical knee and the enhanced knee structures can improve the ability to investigate knee joint biomechanics during various gait activities.     

Floral and vegetative morphometrics of three Platonia insignis Mart. (Clusiaceae) populations,a native tree from the Brazilian Amazon

Platonia insignis Mart. (Clusiaceae), the bacurizeiro, is a native tree species from the Brazilian Amazon forests. Three populations of P. insignis have been observed in the north-east region of the state of Maranhão that differ in flower color: the red population that produces dark pink flowers, the pink population that produces light pink flowers, and the white population with yellowish-white flowers. From multivariate statistical analysis, we aimed at characterizing such populations using morpho-anatomical leaf and flower morphology parameters. A total of 40 P. insignis individuals have been sampled in the cities of São Luís and Chapadinha. The morphological traits varied more than the anatomical traits. Area, fresh mass, and dry mass were the leaf parameters that show more variations. Platonia insignis have hypostomatic or amphihypostomatic leaves. The length of the gynoecium+the length of the nectary, the total length and the length of gynoecium were the principal components considering flower analysis. The three populations did not show significant differences nor did they group using Ward's method. Individuals from the Chapadinha and São Luís red population have been separated according to leaf and flower morphological traits, and the morphological difference between individuals may represent early stages of geographical speciation.