Current-voltage relations during illumination: photoreceptor membrane of a barnacle

In voltage clamped photoreceptor cells of the barnacle, light-induced membrane current varied nonlinearly with membrane potential and changed sign at about + 27 millivolts (reversal potential) independently of light intensity. Instantaneous current-voltage relations were linear and intersected the voltage axis at the reversal potential. Illumination increased membrane conductance that was dependent on membrane potential, light intensity, and time.     

Giant Muscle Fibers in a Barnacle, Balanus nubilus Darwin

Cross-striated muscle fibers of very large size have been found in the scutal-tergal adductor and depressor muscles of the large barnacle B. nubilus. Adductor muscle fibers are up to 2 mm thick. They are innervated by separate nerves, each supplying one end, but not the central region, with terminals; each fiber receives two or three excitor axons. Depressor muscle fibers are up to 1.4 mm thick and receive multiterminal innervation along their entire length; they are innervated by two excitor axons. Postsynaptic potentials are of small or large size and lead to small or large twitches; they do not show facilitation. The muscle fibers shorten to as little as one-sixth resting length.     

电生理技术在昆虫学研究中的研究进展

对电生理技术在昆虫毒理学、害虫抗药性、昆虫视觉等领域中的应用研究现状进行了综述,并讨论了电生理技术在昆虫学研究上的发展前景.     

电生理技术在昆虫毒理学上的应用

对电生理技术在杀虫剂作用机制，新杀虫剂筛选及害虫防治等昆虫毒理学领域上的应用进行了综述，并讨论了电生理技术在昆虫毒理研究上的发展前景。     

Suppression of reflex postural tonus: a role of peripheral inhibition in insects

Postural reflexes act through a single excitatory motoneuron of the several that innervate a flexor muscle of the cockroach leg. A peripheral inhibitory neuron whose axon accompanies this excitatory motoneuron is able to suppress muscle tensions developed from postural reflexes without affecting centrally generated muscle tensions. The inhibitory neuron could thus serve to rapidly suppress postural tensions at the initiation of escape.     

Rate of intracellular diffusion as measured in barnacle muscle

The rate of intracellular diffusion of water, urea, and glycerol was measured in the giant barnacle Balanus nubilus. The calculated diffusion coefficients were not different from those values reported for dilute solutions.     

藤壶金星幼虫附着变态机制

藤壶属节肢动物门(Arthropoda)甲壳亚门(Crustacea)蔓足下纲(Cirripedia)围胸总目(Thoracica), 具备特殊的形态结构、生活史和种群生态特征,是最主要的海洋污损生物。其幼虫阶段通常经历6期无节幼体和1期不摄食的金星幼虫,从浮游的金星幼虫附着变态成固着的稚体是藤壶生活史中的一个关键环节。外界化学和生物因子中成体提取物、水溶性信息素、足迹、神经递质、激素、生物膜等均影响藤壶金星幼虫的附着变态;内在因子即金星幼虫的生理状态(能量储量和年龄)决定了其对外界因子的反应程度。概括了近年来藤壶附着变态生理机制和分子机制研究的进展,可为深入了解藤壶金星幼虫附着变态机制提供参考,也为开发新型、高效、环保的防污剂提供理论指导。     

Long-term habituation of a defensive withdrawal reflex in aplysia

A tactile stimulus to the siphon of Aplysia produces a defensive withdrawal reflex consisting of contraction of the siphon, the gill, and the mantle shelf. We studied long-term habituation of this reflex using two types of preparations, one focusing on the siphon component and the other on the gill component of the reflex. Siphon withdrawal, studied in unrestrained animals, showed marked habituation within a single ten-trial training session. Five daily training sessions produced habituaton that built up across days and lasted for at least 3 weeks. Furthermore, spaced training produced significantly longer lasting habituation than massed training. Gill withdrawal, studied in a restrained animal, also showed long-term retention of habituation. Since the neural circuitry of gill withdrawal is relatively well understood, it may be possible to study the cellular mechanisms underlying a long-term behavioral modification.     

Long-term sensitization of a defensive withdrawal reflex in Aplysia

When a weak tactile stimulus is applied to the siphon of Aplysia californica, the animal withdraws the siphon between the parapodia. This defensive withdrawal reflex can be facilitated (sensitized) if the animal is previously given 4 days of training, consisting of four brief noxious stimuli each day. The sensitization of this reflex can last for up to 3 weeks after training and is mediated by the abdominal ganglion which also mediates long-term habituation. This preparation may provide a system for analyzing the neural mechanism of long-term behavioral modifications of complexity which is intermediate between habituation and associative learning.     

CDC25: a component of the RAS-adenylate cyclase pathway in Saccharomyces cerevisiae

The yeast Saccharomyces cerevisiae contains two functional homologues of the ras oncogene family, RAS1 and RAS2. These genes are required for growth, and all evidence indicates that this essential function is the activation of adenylate cyclase. In contrast, ras in mammalian cells does not appear to influence adenylate cyclase activity. To clarify the relation between ras function in yeast and in higher eukaryotes, and the role played by yeast RAS in growth control, it is necessary to identify functions acting upstream of RAS in the adenylate cyclase pathway. The evidence presented here indicates that CDC25, identified by conditional cell cycle arrest mutations, encodes such an upstream function.     

Intervacuole exchange in the yeast zygote: a new pathway in organelle communication

A new pathway of vesicle traffic between organelles has been identified. The vacuoles (lysosomes) of Saccharomyces cerevisiae zygotes rapidly exchange their contents at a specific point in the cell cycle. With the use of fluorescence microscopy, "tracks" were observed that connect the original parental vacuoles to the newly forming bud vacuoles. These observations suggest that vacuole-derived vesicles rapidly move along the tracks in both directions, equilibrating vacuole contents. This rapid vesicle movement may be responsible for vacuole formation in newly developing cells.