The role of leaf surface wetness in larval behaviour of the sorghum shoot fly, Atherigona soccata

The susceptibility of sorghum to the shoot fly Atherigona soccata Rondani, (Diptera: Muscidae) is affected by seedling age and is highest when seedlings are 8–12 days old. This corresponds with high moisture accumulation on the central leaf which is the path of newly hatched larva as it moves downwards from the oviposition site, towards the growing apex. Studies showed that leaf surface wetness (LSW) of the central shoot leaf was higher in 10-day old seedlings than in seedlings of other ages. Similarly, LSW was much higher in the susceptible sorghum genotype CSH 1 than in the resistant genotype IS 2146. Larvae moved faster towards the growing point and produced deadhearts much earlier in CSH 1 than in IS 2146. They also moved faster in 10-day old seedlings than in seedlings of other ages. It was also shown that the leaf surface wetness of the central shoot leaf is a more reliable parameter of resistance than the glossy leaf trait or trichome density.

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L'influence de la humidité de la surface foliaire sur le comportement de la mouche des pousses du sorgho

Résumé La sensibilité du sorgho à la mouche des pousses du sorgho, Atherigona soccata Rondani, est liée à l'âge de la plantule. Elle est plus forte lorsque la plantule est âgée de 8 à 12 jours et la sensibilité est maximale à 10 jours. A ce stade de croissance on observe une forte accumulation d'humidité sur la feuille centrale de la tige. Les jeunes larves traversent cette zone humide lorsqu'elles descendent vers la zone de croissance à partir des pontes déposées sur la face ventrale des feuilles déroulées.Des études ont été menées à l'ICRISAT (Inde) sur la relation entre l'humidité de la feuille centrale de la tige des plantules du sorgho et les dégâts provoqués par la mouche des pousses. L'humidité de la surface des feuilles (HSF) a été estimée grâce à une échelle visuelle graduée 1 à 5 où, 1 = pas d'humidité apparente et 5 = surface de la feuille recouverte de gouttes d'eau. La HSF est plus élevée sur des pousses de sorgho âgées de 10 j que sur les pousses appartenant à d'autres classes d'âge. Les valeurs observées sont également plus fortes pour les variétés non résistantes à ce ravageur (CSH 1,4.8) que pour les variétés résistantes (IS 2146, (2)). La vitesse du déplacement larvaire entre le cornet et la zone de la croissance varie en fonction de l'âge de la plante et des cultivars. Les larves migrent plus rapidement vers la zone de croissance et provoquent la mort du coeur du sorgho plus tôt dans la variété CSH 1 que dans IS 2146. Les larves se déplacent plus rapidement dans les pousses âgées de 10 j que dans les pousses appartenant à d'autres classes d'âge.Des études ont également démontré que la HSF n'est pas directement liée au caractère feuille lisse où à la densité des trichomes. La HSF est faible pour les génotypes résistants présentent où non le caractère feuille lisse. Par contre la HSF est élevée pour les génotypes non résistants présentant le caractère feuille lisse ou non. Aucune relation directe entre la densité des trichomes et les dégâts provoqués par la mouche des pousses n'a pu être mise en évidence. L'analyse des correlations établie pour les caractères de surface des feuilles avec la mort du cur des sorghos indique que les correlations sont faibles et non-significatives pour le caractère feuille lisse (0.49) et la densité des trichomes (0.39 et 0.2). Par contre les correlations sont fortes et significatives pour la HSF (0.82).On conclue que la HSF de la feuille centrale de la tige est un facteur important dans le déterminisme de la résistance du sorgho vis à vis de la mouche des pousses. Les relations entre les processus physiologiques de la plante et les facteurs impliquées dans l'accumulation d'eau sur la surface des feuilles font actuellement l'objet d'études détaillées.

     

Substructural morphogenesis of the spindle apparatus in meiotic basidia ofCoprinus micaceus (Agaricales)

The spindle apparatus ofCoprinus micaceus begins to develop from the diglobular polar body outside the nucleus. During both meiotic divisions it operates inside the nuclear envelope and consists of two amorphous poles, a central bundle of interpolar microtubules, and chromosomal microtubules. A metaphase plate cannot exist because the interpolar strand of fibers is persistent throughout the division process. Within the spindle axis more than 100 microtubules can be estimated. They are encircled by a ring of chromatic structures. During the telophase the former spindle pole is evaginated from the nuclear envelope and contacts the plasmalemma near the cell wall.     

Processing of vibratory and acoustic signals by ventral cord neurones in the cricket Gryllus campestris

The responses of single vibratory receptors and ascending ventral cord interneurones were studied extracellularly in Gryllus campestris L. The physiology of the vibration receptors resembled those found in tettigoniids and locusts. The frequency responses of the subgenual receptors provide two possible cues for central frequency discrimination: differences in mean tuning between groups of receptors in the different leg pairs and a range of receptors tuned to different frequencies within one subgenual organ.Most of the ascending vibratory interneurones were highly sensitive in either the low or high frequency range. Broadbanded neurones were less sensitive. The characteristic sensitivity peaks of these units are due mainly to receptor inputs from a particular leg pair, although most central neurones receive inputs from all 6 legs. Only one neurone type, TN1 received excitatory inputs from both auditory and vibratory receptors; its responses were greatly enhanced by the simultaneous presentation of both stimulus modes. The responses to sound stimuli of AN2, on the other hand, were inhibited by vibration. No other auditory interneurones investigated were influenced by inputs from vibration receptors. Central processing of vibratory information in the cricket is compared with that of tettigoniids and locusts.     

Homarus Americanus Stomatogastric Nervous System Dissection

With the goal of understanding how nervous systems produce activity and respond to the environment, neuroscientists turn to model systems that exhibit the activity of interest and are accessible and amenable to experimental methods. The stomatogastric nervous system (STNS) of the American lobster (Homarus americanus; also know was the Atlantic or Maine lobster) has been established as a model system for studying rhythm generating networks and neuromodulation of networks. The STNS consists of 3 anterior ganglia (2 commissural ganglia and an oesophageal ganglion), containing modulatory neurons that project centrally to the stomatogastric ganglion (STG). The STG contains approximately 30 neurons that comprise two central pattern generating networks, the pyloric and gastric networks that underlie feeding behaviors in crustaceans^1,2. While it is possible to study this system in vivo³, the STNS continues to produce its rhythmic activity when isolated in vitro. Physical isolation of the STNS in a dish allows for easy access to the somata in the ganglia for intracellular electrophysiological recordings and to the nerves of the STNS for extracellular recordings. Isolating the STNS is a two-part process. The first part, dissecting the stomach from the animal, is described in an accompanying video article⁴. In this video article, fine dissection techniques are used to isolate the STNS from the stomach. This procedure results in a nervous system preparation that is available for electrophysiological recordings.     

中心静脉导管引流对单孔胸腔镜肺癌根治术患者术后胸腔引流的应用分析

目的:探讨中心静脉导管引流对单孔胸腔镜肺癌根治术患者术后胸腔引流的应用效果。方法:回顾性选取2019年1月至2019年12月期间我院收治的行单孔胸腔镜肺癌根治术患者80例的临床资料,根据引流方式的不同分为A组(n=40,传统引流)和B组(n=40,中心静脉导管引流),对比两组患者临床指标、生活质量、炎性因子及并发症发生情况。结果:B组引流操作时间、术后住院时间短于A组(P0.05)。两组术后3个月生活质量简表(SF-36)各维度评分均较术前升高,且B组高于A组(P0.05)。两组术前、术后3d、术后7d白介素-6(IL-6)、C反应蛋白(CRP)、肿瘤坏死因子-α(TNF-α)呈先升高后下降趋势,且术后3d、术后7d B组以上指标低于A组(P0.05)。两组术后并发症发生率比较无差异(P0.05)。结论:与传统引流相比,单孔胸腔镜肺癌根治术患者术后采用中心静脉导管引流,效果显著,可减少炎性刺激,安全可靠,有效改善患者术后生活质量。     

超连续谱激光可见谱段致人眼眩目效应研究

本文采用超连续谱激光光源滤除其红外部分仅输出可见谱段部分,在不超过国家安全标准允许的最大辐照量条件下,以正入射方式照射人眼后,记录并分析在明、暗适应条件下中心极限视力恢复时间、中心近极限视力恢复时间和视觉后像持续时间,明确超连续谱激光可见谱段对人眼的眩目效果。明适应下激光照射0.1 s导致人眼中心极限视力恢复时间为31~119 s,中心近极限视力恢复时间为19~76 s;暗适应下激光照射0.1 s导致人眼中心极限视力恢复时间为26~223 s,中心近极限视力恢复时间为13~123 s;明、暗适应下导致人眼眩目效应的最小功率密度值分别为0.055 mW/cm^2和0.005 mW/cm^2。结果表明,超连续谱激光可见谱段对人眼有良好的眩目效果,可导致数十秒至数百秒的中心视力下降,随着照射功率密度增高,眩目效应增强,显示出较好的量效关系,且相同功率密度时暗适应下人眼的眩目效果优于明适应。该研究探究了明、暗适应条件下超连续谱激光对人眼眩目效应,明确了超连续谱激光与人眼眩目的量效关系。     

Molecular mechanisms of homeostatic plasticity in central pattern generator networks

Central pattern generator (CPG) networks rely on a balance of intrinsic and network properties to produce reliable, repeatable activity patterns. This balance is maintained by homeostatic plasticity where alterations in neuronal properties dynamically maintain appropriate neural output in the face of changing environmental conditions and perturbations. However, it remains unclear just how these neurons and networks can both monitor their ongoing activity and use this information to elicit homeostatic physiological responses to ensure robustness of output over time. Evidence exists that CPG networks use a mixed strategy of activity‐dependent, activity‐independent, modulator‐dependent, and synaptically regulated homeostatic plasticity to achieve this critical stability. In this review, we focus on some of the current understanding of the molecular pathways and mechanisms responsible for this homeostatic plasticity in the context of central pattern generator function, with a special emphasis on some of the smaller invertebrate networks that have allowed for extensive cellular‐level analyses that have brought recent insights to these questions.     

Assessing the effectiveness of foraging radius models for seabird distributions using biotelemetry and survey data

Relatively simple foraging radius models have the potential to generate predictive distributions for a large number of species rapidly, thus providing a cost-effective alternative to large-scale surveys or complex modelling approaches. Their effectiveness, however, remains largely untested. Here we compare foraging radius distribution models for all breeding seabirds in Ireland, to distributions of empirical data collected from tracking studies and aerial surveys. At the local/colony level, we compared foraging radius distributions to GPS tracking data from seabirds with short (Atlantic puffin Fratercula arctica, and razorbill Alca torda) and long (Manx shearwater Puffinus puffinus, and European storm-petrel Hydrobates pelagicus) foraging ranges. At the regional/national level, we compared foraging radius distributions to extensive aerial surveys conducted over a two-year period. Foraging radius distributions were significantly positively correlated with tracking data for all species except Manx shearwater. Correlations between foraging radius distributions and aerial survey data were also significant, but generally weaker than those for tracking data. Correlations between foraging radius distributions and aerial survey data were benchmarked against generalised additive models (GAMs) of the aerial survey data that included a range of environmental covariates. While GAM distributions had slightly higher correlations with aerial survey data, the results highlight that the foraging radius approach can be a useful and pragmatic approach for assessing breeding distributions for many seabird species. The approach is likely to have acceptable utility in complex, temporally variable ecosystems and when logistic and financial resources are limited.     

Trigonostemons G and H,dinorditerpenoid dimers with axially chiral biaryl linkage from Trigonostemon chinensis

Trigonostemons G and H, two novel dimeric dinorditerpenoids, were isolated from the stem barks of Trigonostemon chinensis. Their planar structures and relative configurations were established by extensive analysis of spectroscopic data. Trigonostemons G and H possess a homodimeric biaryl skeleton obtained from two rearranged chiral nonracemic abietane-type dinorditerpenes through an axially chiral biaryl 11,11′-linkage. Torsional scan and computation of the transition states were carried out to estimate the rotational energy barrier, and the axial chirality (aS) was determined by time-dependent density functional theory (TDDFT) electronic circular dichroism (ECD) calculations. The positive n-π* ECD transitions of the isolated carbonyl chromophore above 300 nm could be used to determine the central chirality of trigonostemon G independently by ECD calculations of the diastereomers.     

Male flowers in Tulipa pumila Moench (Liliaceae) potentially originate from gender diphasy

We found functionally male individuals in an otherwise hermaphroditic population of Tulipa pumila (Liliaceae) located in Tuscany (central Italy). We investigated the sex ratio of this population, followed by morphometric analyses of the scape, leaves and flowers, and tests on pollen germinability and seed number and mass, in order to infer which sexual strategy produced the observed co-occurrence of male and hermaphrodite individuals. We found that sex ratio deviated from 1:1, and functionally male individuals showed a smaller plant size and a reduced pollen fitness (germinability and siring ability) compared to hermaphrodites. These findings point to a resource-dependent sexual allocation strategy, probably associated with gender diphasy.