Behavioral Responses of Walleye Pollock, Theragra Chalcogramma, Larvae to Experimental Gradients of Sea Water Flow: Implications for Vertical Distribution

Walleye pollock larvae under controlled laboratory conditions were exposed to vertical gradients of sea water flow in low and high light. Whether flow originated from the surface or the bottom, larvae responded by altering depth distribution, showing attraction to low flows, avoidance of higher flows and when flow was above a threshold level, loss of ability to orient, swim and feed. These results demonstrate that walleye pollock have the capability for responding to gradients of flow by adjusting their vertical distribution. Walleye pollock and many other pelagic fish larvae have weak swimming capabilities and are generally unable to directly control horizontal distributions in the sea by swimming in higher flow regimens. However, using vertical migration, larvae may select conditions of flow direction and speed which are favorable for feeding and predator avoidance and which indirectly allow them to control transport, aggregation and dispersion.     

Enhanced antibody production associated with altered amino acid metabolism in a hybridoma high-density perfusion culture established by gravity separation

A high density hybridoma perfusion culture was established by separating and recycling cells from the product stream to the reactor using a simple external sedimentation-based separator — an inclined modified Erlenmeyer flask. After 3 weeks, when the optimal perfusion rate of 1.0 day^–1 had been reached, viable cell density stabilized at around 10×10⁶ cells ml^–1, a level five times that obtained by simple batch culture. The efficiency of the separator was enhanced by cell flocculation. Specific antibody productivity, which was initially 0.4 g 1×10⁶ cells^–1 h^–1, decreased to half that value while cell density was increasing, but recovered to the initial level when the culture finally stabilized at a high cell density. During the final phase, when viable cell density and specific antibody production were high, there was a marked shift in metabolism. Consumption of the two most important substrates for energy generation, glucose and glutamine, caused their broth concentrations to decrease to 1.5 mM and 1 mM, respectively, from input medium concentrations of 25 mM and 10 mM, respectively. At the same time there was an increase in the specific production of glycine and aspartate, their broth concentrations reaching 1.5 mM and 0.02 mM, respectively. We suggest that this shift in metabolism results in enhanced production of ATP from glutamine. The specific glucose consumption and lactate production also indicate that there is a shift to more energy efficient metabolism. The mechanism whereby this leads to enhanced specific antibody production remains to be elucidated. Nevertheless, the combination of high cell density and enhanced productivity obtained with the present perfusion culture resulted in a high monoclonal antibody production –100 mg l^–1 d^–1.     

面向居民生态福祉的国土空间生态网络构建——以临沂市为例

构建面向居民福祉的生态安全体系，统筹考虑生态安全格局中的生态系统要素连通关系和生态系统服务供需关系，是强化国土空间生态修复规划成果，提升居民生态福祉的重要途径。研究基于"源-汇"理论，构建景观生态安全维育网络与生态系统服务亲近网络。结果显示：（1）45%的生态系统服务保护目标是实现高生态系统服务供给和低机会成本的合理阈值，基于此识别的生态供给源地面积为1230.89km²，中心城区及部分主要街道的生态系统服务供需关系呈现高需求-低供给现象；（2）共识别景观生态安全维育廊道75条，其中重要廊道1054km，次重要廊道1154km，一般廊道1366km；（3）生态系统服务亲近廊道分为10个组团，网络化程度低，西北部主要由森林构成，中东部主要由沿河湿地提供服务；（4）构建临沂市"三区两带五廊多组团"的国土空间生态安全格局，在保障景观生态安全的同时有效协调区域生态系统服务供求关系，促进生态-社会协同可持续发展。     

Geotaxis in the springtail Folsomia candida

Laboratory assays demonstrated the presence of a small positive geotaxis response to a 15° incline by Folsomia candida Willem (Collembola: Isotomidae). Negative phototaxis played an additive role to positive geotaxis when the experimental apparatus were exposed to light. The geotactic response was negatively affected by cold acclimation and decreasing surrounding temperature, but unaffected by food deprivation. The reduced mobility of springtails at low temperature did not seem to play a role in the corresponding decreased geotaxis. The low level of geotaxis and its further decrease with exposure to low temperature support an earlier suggestion that F. candida do not respond to cooling temperatures of fall by relocation to warmer deeper soil layers, but remain in the upper soil layers and increase their cold tolerance to continue foraging in the food‐rich upper soil layers.     

Modification of the gravitropic response of seedling roots of raneseed (Brassica napus) transformed by Agrobacterium rhizogenes A4

We have examined the growth and gravitropic response of seedling roots of rapeseed ( Brassica napus . CrGC5–1) transformed by Agrobacterium rhizogenes A4, in order to evaluate if this could constitute a new model system for the study of gravitropism. The transformed clone chosen for study had integrated full-length TL- and TR-DNA from pRi (the root inducing plasmid), and thus included all of the agrobacterial genes potentially involved in the modified phenotype of transformed plants. In the vertical position, the growth rate of transformed roots was higher than controls. During 24 h of continuous stimulation, the optimal angle for gravitropic bending in normal roots was 135° (with respect to the gravity axis), with decreasing response at 90° and 45°. For transformed roots, slight curvature developed at 45° and at 90°, and stronger curvature was observed at 135°, though transformed roots tips never reached the vertical position. The minimum stimulation time necessary to elicit a response (presentation time) was also determined: it was signficantly shorter in normal roots (80 s) than in transformed ones (120 s). The results show that pRi transformed roots are less sensitive to gravity than normal roots.     

Experiments on the responses of the larval stages of the geometrid moth Ectropis excursaria to light and gravity

The intensity-response curve to light in a vertical plane (where gravity was a conflicting stimulus to light) and a horizontal plane (where gravity was not a conflicting stimulus) suggests that the climbing behaviour of the first instar Ectropis excursaria (Guénée) is consistent with a summation of response to gravity and a response to light. Response to gravity was affected by the curvature of the crawling surface and the level of food deprivation of the caterpillars. On a 2 cm diameter crawling surface orientation to gravity occurred at an inclination between 20° and 30° from the horizontal. In a centrifugal field, a behaviour analogous to negative geotaxis occurred at accelerations of 3.5 ms^–2. Analysis of the geotactic turning tendencies of the caterpillar on flat inclined planes suggests that they exhibit meta-geotactic behaviour from inclinations of 40 to 90°. Negative geotaxis was exhibited by the caterpillars of later stadia although a response to gravity was lacking in the prepupal wandering caterpillars. The pre-pupal stage was also characterized by a reversal of the response to light.

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Résumé Un comportement d'escalade du premier stade d'E. excursaria correspondant à l'addition des réponses à la gravité et à la lumière, est suggéré par la courbe d'intensité de la réponse à la lumière, dans un plan vertical (où la gravité constitue un stimulus en opposition avec la lumière) et un plan horizontal (où la gravité n'est pas en opposition). La réponse à la gravité a été modifiée par la courbure de la surface à escalader et du degré de privation d'aliment des chenilles. Sur une surface d'escalade de 2 cm de diamètre, l'orientation par rapport à la gravité se produit entre 20 et 30° par rapport à l'horizontale. Das run champ de centrifugation, un comportement analogue à une géotaxis négative se produit pour une accélération de 3,5 m s^–2. L'analyse des tendances géotactiques des chenilles à tourner sur des plans inclinés suggère qu'elles présentent un comportement métagéotactique pour les inclinaisons de 40 à 90°. Des expériences d'immobilisation laissent penser que les antennes jouent un rôle dans la perception de la gravité. Les chenilles de stades ultérieurs ont présenté une géotaxie négative bien que la réponse à la gravité disparaisse chez les chenilles vagabondes en prénymphe. La prénymphose est aussi caractérisée par une inversion des réponses à la lumière.

     

Biomarkers of age effect on renal function in Down syndrome

Objective: To assess differences in kidney function between Down syndrome (DS) individuals and a control group related to aging.

Methods: Creatinine (Cr) and specific gravity (SG) were assessed by spectrophotometric and refractometric assays in urine samples of 103 individuals with DS and 82 age-matched controls.

Results: Significantly lower levels of Cr and SG were found in DS after puberty. Significant correlations were found between SG and age as well as between Cr and SG in DS and controls (p?≤?0.05).

Conclusions: Premature aging in kidneys of DS patients could lead to an impaired renal function.     

Cell cultivation under different gravitational loads using a novel random positioning incubator

Important in biotechnology is the establishment of cell culture methods that reflect the in vivo situation accurately. One approach for reaching this goal is through 3D cell cultivation that mimics tissue or organ structures and functions. We present here a newly designed and constructed random positioning incubator (RPI) that enables 3D cell culture in simulated microgravity (0 g). In addition to growing cells in a weightlessness‐like environment, our RPI enables long‐duration cell cultivation under various gravitational loads, ranging from close to 0 g to almost 1 g. This allows the study of the mechanotransductional process of cells involved in the conversion of physical forces to an appropriate biochemical response. Gravity is a type of physical force with profound developmental implications in cellular systems as it modulates the resulting signaling cascades as a consequence of mechanical loading. The experiments presented here were conducted on mouse skeletal myoblasts and human lymphocytes, two types of cells that have been shown in the past to be particularly sensitive to changes in gravity. Our novel RPI will expand the horizon at which mechanobiological experiments are conducted. The scientific data gathered may not only improve the sustainment of human life in space, but also lead to the design of alternative countermeasures against diseases related to impaired mechanosensation and downstream signaling processes on earth. Biotechnol. Bioeng. 2014;111: 1180–1190. © 2013 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.     

固态间歇补料乙醇生料发酵新工艺

浓醪发酵是酒精生产的发展方向。与现行酒精厂普遍采用的热蒸煮工艺相比, 生料发酵技术的发展使得浓醪发酵更容易进行。本研究首次在生料发酵中直接采用固态原料间歇补料, 比较了STARGENTM生淀粉水解酶间歇补料工艺和传统无补料工艺, 并对不同补料方式进行了研究。结果表明: 与传统无补料生料发酵工艺相比, 在相同的干基配料浓度30%、相同的生料酶添加量0.22%(W/W)的条件下, 采用15%的起始配料浓度、发酵15~25 h进行间歇补料的新工艺, 酒精产量从17.06%提高到18.50%。该间歇补料优化工艺的建立, 丰富了生料发酵技术的应用。