Molecular neurophysiology of taste in <Emphasis Type="Italic">Drosophila</Emphasis>

The recent identification of candidate receptor genes for sweet, umami and bitter taste in mammals has opened a door to elucidate the molecular and neuronal mechanisms of taste. Drosophila provides a suitable system to study the molecular, physiological and behavioral aspects of taste, as sophisticated molecular genetic techniques can be applied. A gene family for putative gustatory receptors has been found in the Drosophila genome. We discuss here current knowledge of the gustatory physiology of Drosophila. Taste cells in insects are primary sensory neurons whereupon each receptor neuron responds to either sugar, salt or water. We found that particular tarsal gustatory sensilla respond to bitter compounds. Electrophysiological studies indicate that gustatory sensilla on the labellum and tarsi are heterogeneous in terms of their taste sensitivity. Determination of the molecular bases for this heterogeneity could lead to an understanding of how the sensory information is processed in the brain and how this in turn is linked to behavior.Received 12 May 2003; received after revision 9 June 2003; accepted 13 June 2003     

层叠式锂离子电池展向温度分布的分析解及基于分析解的热设计优化

大型锂离子动力电池的热相关问题是限制其在电动汽车上大规模应用的主要问题之一.单体电池的热模型是进行电池热设计、改善电池热特性的重要工具.根据热模型的求解方法,可分为数值解和分析解两类.在现有文献的研究中,数值解占据了主要地位.但是,分析解因具有计算量小、可实现设计变量的全局优化等优点,在电池热设计和电池组热管理系统中可发挥重要作用.例如,在电池热设计中,分析解可全面考察多个设计参数连续变化下对电池热特性的影响,以进行多设计参数下的全局优化.本文首先对一款大型层叠式锂离子电池进行了数值热模拟和实验验证,数值热模拟的结果与多枚热电偶的实验测量结果吻合良好;然后,基于数值热模拟的结果提取了层叠式电池温度分布和产热率分布的主要特点,进而假设温度呈展向平面分布、产热率均匀分布;针对简化后的电池热问题,利用双重积分变换方法提出了分析解;最后,使用分析解开展了电池的热设计优化工作,讨论了不同电芯尺寸和极耳布置方案下的电池热特性.     

Influence of age on epidermal growth factor receptor level in the rat brain

Summary The influence of age on¹²⁵I-epidermal growth factor (EGF) binding to rat brain plasma membranes was investigated. The specific binding of EGF to membranes decreased gradually with age in both male and female rats. There was no significant difference in the specific binding between males and females. Scatchard analysis of the binding data showed that the decrease in EGF binding with age was due to a decrease in the number of EGF receptors.     

Influence of brown adipose tissue on deep cervical temperature during sleep in the young rabbit

Summary In young rabbits the slope of the temperature in the deep cervical region close to brown adipose tissue increased during desynchronized sleep at low ambient temperature. No increase occurred at neutral ambient temperature. In control rabbits (after disappearance of brown adipose tissue), the slope of deep cervical temperature did not increase during desynchronized sleep at low or neutral ambient temperatures.Preliminary data were reported at the Association des Physiologistes, Réunion de Poitiers, 20–23 June 1983.Acknowledgments. We wish to thank Giuseppe Mancinelli and Leonida Sabattini for technical assistance. This work was supported by a grant from the Consiglio Nazionale delle Ricerche, Rome. J.P.L. wishes to thank NATO for partial financial support during his stay at the Physiology Department in Bologna.     

COPD大鼠肺组织中 LTB4水平、5 LOmRNA表达及齐留通的干预作用

目的探讨慢性阻塞性肺疾病(chronicobstructivepulmonarydisease,COPD)大鼠模型肺组织中白三烯 B4(LeukotrieneB4, LTB4)含量与5 脂氧合酶(5 LO,5 lipoxygenase)mRNA水平的变化,以及给予齐留通干预的影响.方法36只健康雄性 Wistar大鼠随机分为对照组、模型组、药物组,采用被动吸烟法制作 COPD大鼠模型,给予药物组鼻饲齐留通,测定肺功能,各组肺组织匀浆检测其 LTB4含量及髓过氧化物酶(Myeloperoxidase,MPO)活性,RT PCR法检测5 LOmRAN的表达.结果模型组、药物组的0.3秒用力呼吸容积(Forcedexpiratoryvolumeinthe0.3second,FEV0.3)/用力肺活量(Forcedvitalcapacity,FVC)%较对照组显著下降(P<0.001),吸气相阻力(Inspiratoryphaseresistance,Ri)和呼气相阻力(expiratoryphaseresistance,Re)较对照组显著增加(P<0.001,P<0.05);模型组较药物组 FEV0.3/FVC%下降程度更低,Ri、Re更高,两组间差异有显著性(P<0.05).比较各组大鼠肺组织 LTB4水平,MPO活性及5 LOmRNA表达:模型组、药物组较对照组显著升高(P<0.001);与模型组比较,齐留通干预使得三项指标均有显著降低(P<0.001).结论 LTB4及5 LO参与 COPD的气道炎症过程.5 LOX抑制剂齐留通可部分抑制减少 COPD大鼠肺组织中 LTB4产生,其机制可能为抑制5 LO表达     

Induction of cyst formation by low temperature in the dinoflagellateGonyaulax polyedra Stein: Dependence on circadian phase and requirement of light

Encystment, which at a temperature of 15°C is photoperiodically controlled inGonyaulax polyedra, can also be induced by a decrease of temperature, from 20 to 10 or 8°C in the absence of photoperiodic signals. The cyst-inducing capacity of the decrease in temperature depends on the circadian phase: in constant light, the maximum of sensitivity was found at the beginning of subjective night. In a light/dark cycle, however, cyst formation was reduced during dark phase, indicating that light is required for the process of encystment. A similar light dependence was seen in the effect of the physiologically occurring cyst inducer 5-methoxytryptamine, but not in the encystment response to the protonophores monensin and nigericin.