关于猫颌下腺神经支及其节前神经元的观察

用逆行溃变（Kohnstamm,1902;Yagita,et al.,1909;Torvik,1957）局部电刺激中枢（Chatfield,1942;Magoun et al.,1942;Wang,1943）等方法进行唾液中枢的定位,所得到结果很不一致。近年Satomi（1979）等用辣根过氧化酶（HRP）浸泡猫中间一面神经或鼓索神经,观察了脑干中逆行标记细胞的分布。但用HRP直接浸泡支配猫颌下腺的神经分支尚未见报道。此外,只见到关于鼓索神经纤维类别和数量的分析的光学显微镜研究（Foley,1945）,用光镜和电镜相结合分析颌下腺神经支中的纤     

猫脑干上涎核节前神经元电活动的观察

在麻醉的32只猫记录了电刺激颌下腺神经支引起的上涎核平均场电位和单位放电。逆行电刺激颌下腺神经支引起的上涎核平均场电位分布在同侧脑干背面闩部头端5.5—8mm处,与过去的组织学结果大致符合。用微电极在上涎核记录了68个对刺激颌下腺神经支有反应的单位,其中33个单位作了碰撞试验。有9个单位符合逆向反应标准,它们是真正的颌下腺节前神经元,逆行反应的潜伏期为14.4±2.5ms,其轴突传导速度为2.9±0.1m/s。其他不符合逆向反应标准的单位,对刺激颌下腺神经支仍能发生反应,估计多为中间神经元。在一部分单位观察了电刺激舌神经或味觉刺激舌引起的反应。根据这些观察对上涎核内存在复杂神经元回路的可能性作了讨论。     

Canopy development of a determinate and an indeterminate cultivar of Vicia faba L. under contrasting plant distributions and densities

Field experiments were conducted in 1987 and 1988 to quantify differences in canopy formation between an indeterminate and a determinate genotype of Vicia faba L., grown at two plant densities and three spatial distributions. The number of stems per unit area produced by determinate plants was related to the growth rate before flowering. Leaf production per stem per unit of thermal time was similar in both plant types, but twice as many leaves per stem were produced by the indeterminate cultivar. The indeterminate cultivar produced fewer and smaller leaves in the warmer and drier weather of 1988 than in 1987. The determinate genotype produced similar sizes and numbers of leaves in both years, but fewer tillers developed in 1988 than in 1987. Accordingly, leaf mass per unit ground area was greater in 1987 than in 1988 in both genotypes. Except during early flowering, relationships between leaf mass and leaf area were constant, with higher specific leaf areas in the determinate than the indeterminate genotype. Shoot dry matter partitioning into leaves was identical in both years for indeterminate plants, but differed in determinate ones.
It is concluded that canopy development is regulated through individual leaf weight and leaf number per stem in non-tillering indeterminate, and by stem numbers per unit area in tillering determinate plants.     

Interaction of ozone pollution and light effects on photosynthesis in a forest canopy experiment

Ozone pollution may reduce net carbon gain in forests, yet data from mature trees are rare and the effects of irradiance on the response of photosynthesis to ozone remain untested. We used an open-air system to expose 10 branches within the upper canopy of an 18-m-tall stand of sugar maple (Acer saccharum Marsh.) to twice-ambient concentrations of ozone (95nmol mol^?1, 0900 to 1700, 1 h mean) relative to 10 paired, untreated controls (45nmol mol^?1) over 3 months. The branch pairs were selected along a gradient from relatively high irradiance (PPFD 14.5 mol m^?2 d^?1) to deep shade (0.7mol m^?2 d^?1). Ozone reduced light-saturated rates of net photosynthesis (A_sat) and increased dark respiration by as much as 56 and 40%, respectively. Compared to sun leaves, shade leaves exhibited greater proportional reductions in A_sat and had lower chlorophyll concentrations, quantum efficiencies, and leaf absorptances when treated with ozone relative to controls. With increasing ozone dose over time, A_sat became uncoupled from stomatal conductance as ratios of internal to external concentrations of carbon dioxide increased, reducing water-use efficiency. Ozone reduced net photosynthesis and impaired stomatal function, with these effects depending on the irradiance environment of the canopy leaves. Increased ozone sensitivity of shade leaves compared to sun leaves has consequences for net carbon gain in canopies.     

Evolutionary analysis of the picornavirus family

An exhaustive evolutionary analysis of the picornavirus family has been carried out using the amino acid sequences of several proteins of the viruses including: the capsid proteins (1D, 1B, and 1C) situated at the 5 end of the genome and responsible for the serotype of the viruses, and the viral polymerase (3D), located at the 3 end of the genome. The evolutionary relationships found among the viruses studied support the new classification, recently suggested, in contrast to the classical one, and the existence of a new genus for the picornavirus family. In the new taxonomic organization, five genera form the picornavirus family: (1) aphthoviruses, (2) cardioviruses, (3) hepatoviruses (previously classified as enteroviruses), (4) renteroviruses (which mainly constitute a combination of the previous genera rhinovirus and enterovirus), and (5) a new genus, with a new and unique representative: the echovirus 22. Our analysis also allowed us, for the first time, to propose the most probable sequence of speciation events to have given rise to the current picornavirus family.The bootstrap procedure was used to check the reliability of the phylogenetic trees obtained. The application of the method of the statistical geometry in distance space to internal branches of the tree revealed a high degree of evolutionary noise, which makes the resolution of some internal branching points difficult. Correspondence to: J. Dopazo     

Side branch formation and orientation in the caulonema of the moss,Funaria hygrometrica: Normal development and fine structure

Summary The regular branching of theFunaria caulonema filaments is partly related to rhythms in nuclear and cell division. The formation and development of the branches were studied by light and electron microscopy with particular attention directed to the distribution of microtubules and the polar organization of the cytoplasm. The new side branch breaks through the wall of the mother cell. The site of branch development is determined by the position of the nucleus of the mother cell. In protonemata which grow in vertically placed Petri dishes gravity influences the position of nuclei and side branches, and also the direction of oblique cross walls in the caulonema filaments to a certain extent.     

Phylogeny of snakes (Serpentes): Combining morphological and molecular data in likelihood,Bayesian and parsimony analyses

Abstract

The phylogeny of living and fossil snakes is assessed using likelihood and parsimony approaches and a dataset combining 263 morphological characters with mitochondrial (2693 bp) and nuclear (1092 bp) gene sequences. The ‘no common mechanism’ (NCMr) and ‘Markovian’ (Mkv) models were employed for the morphological partition in likelihood analyses; likelihood scores in the NCMr model were more closely correlated with parsimony tree lengths. Both models accorded relatively less weight to the molecular data than did parsimony, with the effect being milder in the NCMr model. Partitioned branch and likelihood support values indicate that the mtDNA and nuclear gene partitions agree more closely with each other than with morphology. Despite differences between data partitions in phylogenetic signal, analytic models, and relative weighting, the parsimony and likelihood analyses all retrieved the following widely accepted groups: scolecophidians, alethinophidians, cylindrophiines, macrostomatans (sensu lato) and caenophidians. Anilius alone emerged as the most basal alethinophidian; the combined analyses resulted in a novel and stable position of uropeltines and cylindrophiines as the second‐most basal clade of alethinophidians. The limbed marine pachyophiids, along with Dinilysia and Wonambi, were always basal to all living snakes. Other results stable in all combined analyses include: Xenopeltis and Loxocemus were sister taxa (fide morphology) but clustered with pythonines (fide molecules), and Ungaliophis clustered with a boine‐erycine clade (fide molecules). Tropidophis remains enigmatic; it emerges as a basal alethinophidian in the parsimony analyses (fide molecules) but a derived form in the likelihood analyses (fide morphology), largely due to the different relative weighting accorded to data partitions.     

Outflow-tract ventricular tachycardia: Can 12 lead ECG during sinus rhythm identify underlying cardiac sarcoidosis?

BackgroundPatients with outflow tract ventricular tachycardia (OTVT) with normal echocardiogram are labeled as idiopathic VT (IVT). However, a subset of these patients is subsequently diagnosed with underlying cardiac sarcoidosis (CS). Objective:Whether electrocardiogram (ECG) abnormalities in sinus rhythm (SR) can differentiate underlying CS from IVT.MethodsWe retrospectively analyzed the SR-ECGs of 42 patients with OTVT/premature ventricular complexes (PVC) and normal echocardiography. All underwent advanced imaging with cardiac magnetic resonance (CMR)/¹⁸FDG PET-CT for screening of CS. Twenty-two patients had significant abnormalities in cardiac imaging and subsequently had biopsy-proven CS (Cases). Twenty patients had normal imaging and were categorized as IVT (Controls). SR-ECGs of all patients were analyzed by 2 independent, blinded observers.ResultsBaseline characteristics were comparable. Among the ECG features analyzed – fascicular (FB) or bundle branch block (BBB) was seen in 9/22 Cases vs. 1/20 controls (p = 0.01). Among patients without FB or BBB, fragmented QRS (fQRS) was present in 9/13 cases but in none of the controls (p < 0.001). Low voltage QRS was more often seen among cases as compared to controls (10/22 vs. 3/20 p = 0.03). A stepwise algorithm based on these 3 sets of ECG findings helped to diagnose CS among patients presenting with OTVT/PVC with sensitivity of 91%, specificity of 75%, a PPV of 80%, and a NPV of 88%.ConclusionsIn patients presenting with OTVT/PVC: FB/BBB, fQRS, and low QRS voltage on the baseline ECG were more often observed among patients with underlying CS as compared to true IVT. These findings may help to distinguish underlying CS among Cases presenting with OTVT/PVC.     

Two new species of the genus Rhyacophila Pictet (Trichoptera: Rhyacophilidae) from India

Two new species of the genus Rhyacophila Pictet from the Indian Himalayas, i.e. Rhyacophila himalayensis n. sp. from Badrinath (Uttarakhand) of the R. divaricata branch and Rhyacophila indica n. sp. from Gangtok (Sikkim) of the R. vulgaris branch are described and illustrated.