Peripheral and central nervous responses evoked by small water movements in a cephalopod

Potentials were recorded from the epidermal head lines and from the CNS of young cuttlefish, Sepia officinalis, in response to weak water movements. 1. Within the test range 0.5-400 Hz a sinusoidal water movement elicits up to 4 components of response if the electrode is placed on a headline: (i) a positive phasic ON response; (ii) a tonic frequency-following microphonic response; (iii) a slow negative OFF response; and (iv) compound nerve impulses. 2. The amplitude of both the ON wave and the microphonic potential depends on stimulus frequency, stimulus amplitude and stimulus rise time. Frequencies around 100 Hz and short rise times are most effective in eliciting strong potentials. The minimal threshold was 0.06 microns peak-to-peak water displacement at 100 Hz (18.8 microns/s as velocity). 3. Change of direction of tangential sphere movement (parallel vs. across the head lines) has only a small effect on the microphonic and the summed nerve potentials. 4. Frequency and/or amplitude modulations of a carrier stimulus elicit responses at the onset and offset of the modulation and marked changes in the tonic microphonic response. 5. Evoked potentials can be recorded from the brain while stimulating the epidermal lines with weak water movements. The brain potentials differ in several aspects from the potentials of the head lines and show little or no onset or offset wave at the transitions of a frequency and amplitude modulation.     

Morphology of neurons and axon terminals associated with descending and ascending pathways of the lateral forebrain bundle in Rana esculenta

Summary The cells of origin of afferent and efferent pathways of the lateral forebrain bundle were studied with the aid of the cobalt-filling technique. Ascending afferents originated from the lateral thalamic nucleus, central thalamic nucleus, posterior tuberculum and the cerebellar nucleus. They terminated in the anterior entopeduncular nucleus, amygdala and the striatum. Telencephalic projection neurons, which are related to the lateral forebrain bundle, were located mainly in the ventral striatum and the anterior entopeduncular nucleus, but were not so numerous in the dorsal striatum. Irrespective of their location, most of the neurons projecting axons into the lateral forebrain bundle had piriform or pyramidal perikarya. Long apical dendrites usually arborized in a narrow space, whereas widely arborizing secondary dendrites originated from short dendritic trunks. The other neurons that contributed to the lateral forebrain bundle were fusiform or multipolar cells. Striatal efferents terminated in the pretectal area and in the anterodorsal, anteroventral and posteroventral tegmental nuclei.     

椭圆斜羽叶的解剖研究及斜羽叶的系统分类位置

本文根据对椭圆斜羽叶(Plagiozamites oblongifolius)钙质石化化石的研究,认为其主要特征如下:羽状复叶,叶肉无海绵组织和栅栏组织分化。羽片叶脉维管束外韧式,木质部外始式,与现代苏铁属叶脉特征相近。羽轴维管束为“U”形,外始式木质部、梯状纹孔管胞,与现代苏铁属的羽轴维管束相似。根据上述特征,目前可将斜羽叶属归入原始苏铁类植物。但是,如果斜羽叶的生殖器官同 Noeggerathia 一样,为异孢型孢子囊穗,则斜羽叶可能为一种与苏铁类起源有关的原裸子植物。     

On the systematic position of the family Gyrinidae (Coleoptera: Adephaga)

Various characters of adult and larval members of Adephaga and Cupedidae were analyzed, and suggest that Gyrinidae are the sister-group of the remaining Adephaga, and are not closely related to the remaining aquatic Adephaga. The aquatic families Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae seem to form a well founded monophyletic unit. The following characters are considered as synapomorphies of Adephaga excluding Gyrinidae: bifurcate condition of the muscle (= M.) tentoriopraementalis inferior, reduction of hypopharynx, strongly developed prosternal process, reduction in size and specialized modification of the ventral sclerite of the mesothorax, strongly developed mesofurcal arms, a high mesopleural ridge, globular mesocoxae restricted to rotatory movements, invaginated sternum VIII (coxostemum), the strongly curved base of the median lobe of the aedeagus, which articulates with the parameres, the rotated position of the aedeagus in repose, fusion of the larval clypeolabrum with the frons and reduction of the larval lacinia. Mesal shifting of M. episterno-coxalis prothoracis, and the fusion of the apical portions of the malpighian tubules of either side are considered as synapomorphies of Adephaga excluding Rhysodidae and Gyrinidae. Lateral reduction of the meta “sternal” transverse ridge and the presence of the subcubital setal binding patch of the hind wing are considered as synapomorphic characters of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. We postulate that the metacoxal fusion occurred independently in gyrmids and the common ancestor of Trachypachidae, Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae. Consequently we consider this character state as another synapomorphy of Trachypachidae and Hydradephaga excluding Haliplidae and Gyrinidae. The following characters are considered as synapomorphies of Noteridae, Amphizoidae, Hygrobiidae and Dytiscidae: Loss of tactile setae on the head capsule, metafurcal origin on the intercoxal wall, expansion of the intercoxal wall, elongation of the subcubital setal binding patch, loss of Mm. furca-coxale anterior and posterior, reduction of the larval abdominal segments IX and X, and the shifting of the uropmphi onto the ventral side of segment VIII. Presence of M. tentorio-mandibularis and M. stipitopalpalis intemus are certainly primitive features of adult gyrinids but the distribution of these character states among most members of Adephaga is yet unclear. Chemical defence gland constituents point towards a very isolated position of Gyrinidae. The old age of the group, documented by a larva found in upper Permian deposits, may support the hypothesis of a sister-group relation-ship between Gyrinidae and the remainder of Adephaga.     

Autecological investigations on marine diatoms. 5:Coscinodiscus concinnus W. Smith andRhizosolenia setigera Brightwell

The cold oligo-eurytherm diatomsCoscinodiscus concinnus W. Smith andRhizosolenia setigera Brightwell were cultured to determine their best competitive position by growth. Comparison of their generation times with those of other diatoms indicate that they reach this position between 6°C and 12°C. Both species grew between –1.5°C and about 20°C. The experiments indicate thatC. concinnus flowerings are possible in a deep water column, during periods of high light intensities. The simultaneous death of species in the upper layer is also caused by high light intensities.C. concinnus appeared in two morphological forms; the normal voluminous form, and a flatter form with a few intercalary bands only, filled with large oil-droplets. The latter appeared at 0°C and below, and at the upper temperature limit for growth of about 19°C–20°C. The separation of nov. spec. fromC. concinnus based on the absence or presence of a hyaline area and intercalary bands as identification characteristics should be reconsidered.     

Waterstriders (Gerris paludum F.) compensate for drift with a discontinuously working visual position servo

Waterstriders on ponds and creeks compensate for displacement caused by wind or water current with periodical jumps against the direction of drift. This behavior is mediated by visual stimuli.

A Bioluminescence Method for the Measurement of l-Glutamate: Applications to the Study of Changes in the Release of l-Glutamate from Lateral Geniculate Nucleus and Superior Colliculus After Visual Cortex Ablation in Rats

We have developed a rapid, simple, specific, and very sensitive bioluminescence method for the measurement of L-glutamate (L-Glu). Oxidation of L-Glu by glutamate dehydrogenase has been coupled with bacterial FMN reductase and luciferase. Light production (i.e., peak height or integral) was linear from less than 0.5 to 500 pmol of L-Glu. Potential interfering substances that may be encountered in brain tissue have been identified. The most potent inhibitors were ascorbate and the biogenic amines. Procedures that conferred long-term stability of the reagent mixture (greater than 8 h) were established. Bioluminescence analysis of L-Glu content in brain tissue extracts, fractions from release experiments, and human CSF corroborated respective results obtained by HPLC analysis. In this study, we have applied the method to monitor changes in the KCl-evoked release of endogenous L-Glu from milligram amounts of brain tissue, i.e., from lateral geniculate nucleus and superior colliculus after visual cortex ablation.     

关于保留球毛壳与橄榄色毛壳作为不同种的见解

球毛壳(Chaetomium globosum Kze.)系 Kunze 于1817年报道见于丹麦石竹(Dianthus carthusianorum L.)茎上的毛壳菌属(Chaetomium)的第一个种(模式种)。Cooke and Ellis 在1878年描述了见于飞蓬属(Erigeron L.)腐茎上的橄榄色毛壳(C.oliaceum C.et E.)。在 Chivers(1915)、Skolko and Groves(1953)、Udagawa(1960)、Ames(1963)和 Seth(1972)关于毛壳菌属的专著都曾指出很难划分这两个种的界限。Skolk and Groves(1953)区分此两个种时以橄榄色毛壳具有较大的子囊壳、较宽的顶附属丝和较大的子囊孢子,而 Chivers(1915)则认为橄榄色毛壳是球毛壳的异名,Udagawa(1960)区分此两个种仅根据子囊孢子的长度和宽度,他认为橄榄色毛壳的子囊孢子大于球毛壳的子囊孢子。Seth(1972)在他的专著中虽保留此两个种作为独立种,但他指出限于他镜检过的标本材料及根据 Chivers 专著中的球毛壳的特征辑要概括了橄榄色毛壳的特征,对这两个种的区分界限确实是很难划分的。最近我们在北京采集和分离了来源于不同的植物和动物材料上的毛壳菌种类,以期进行北京地区毛壳菌种类调查研究。我们分离获得许多球毛壳——橄榄色毛壳类的毛壳菌菌株。参考了不同作者对这两个种的子囊壳、顶附属丝、侧附属丝、子囊及子囊孢子的特征记载,对北京的这一类型菌株进行了细致研究,认为球毛壳与橄榄色毛壳确有形态学特征区别,表现在橄榄色毛壳的子囊壳、顶附属丝和子囊孢子较球毛壳的更为粗壮,兼之球毛壳的顶附属丝较橄榄色毛壳的为窄且有分隔和微粗糙,球毛壳的子囊孢子呈浅橄榄褐色至暗橄榄褐色,含两个折光性油滴而橄榄色毛壳的子囊孢子呈暗橄榄褐色,量度亦较大,凭依经验即可鉴别此两个不同种。