Life on the edge: a hybrid zone in AZbinaria hippolyti (Gastropoda: Clausiliidae) from Crete

The hybrid zone between the Greek land snails Albinaria hippolyti aphrodite and Albinaria hippolyti harmonia runs exactly along the edge of a gorge. At two localities, we analysed patterns of variation in three enzyme loci, six conchological characters, and two anatomical characters across the zone. Clines in the various characters are largely coincident and concordant. They are narrow (approximately 30 m wide) where the ecological transition is abrupt, and wider (approximately 120 m wide) where a valley cuts into the gorge, making the environmental change more gradual. In spite of the obvious correlation with an ecological transition, we do not believe the zone is maintained by a selection gradient. Instead, direct and indirect evidence for hybrid disadvantage and evidence for directional dispersal at the edge of the gorge suggest that it is a tension zone, held at the ecotone by differential dispersal of at least one of the parental types. We speculate on the possibility that reinforcement may act in the hybrid zone. Our data on dispersal and reproductive isolating mechanisms lead us to believe that reinforcement may only be possible at localities where the hybrid zone is very narrow.     

Plant Sources of Chinese Herbal Remedies: Effects on Pratylenchus vulnus and Meloidogyne javanica

More than 500 plant species, used alone or in combination, are documented in Chinese traditional medicine to have activity against helminth and micro-invertebrate pests of humans. We subjected 153 candidate medicines or their plant sources to multilevel screening for effectiveness against plant-parasitic nematodes. For extracts effective in preliminary screens, we determined time-course and concentration-response relationships. Seventy-three of the aqueous extracts of medicines or their plant sources killed either Meloidogyne javanica juveniles or Pratylenchus vulnus (mixed stages), or both, within a 24-hour exposure period. Of 64 remedies reported as antihelminthics, 36 were effective; of 21 classi- fied as purgatives, 13 killed the nematodes; of 29 indicated as generally effective against pests, 13 killed the nematodes. Sources of extracts effective against one or both species of plant-parasitic nematodes are either the whole plant or vegetative, storage or reproductive components of the plants. Effective plants include both annuals and perennials, range from grasses and herbs to woody trees, and represent 46 plant families.     

Interrelationships and evolution of the east Asian grass lizards, Takydromus (Squamata: Lacertidae)

The east Asian lacertid lizard genus, Takydromus , is well-defined but its relationships to other primitive Palaearctic lacertids are still uncertain and, although it has similarities to the lower Miocene Miolacerta, Takydromus does not appear to be identical with this. The 16 or 17 recognizable species are reviewed and a key provided for their identification; the remaining area of uncertainty about species boundaries is the Takydromus sexlineatus group in Assam. A phylogeny for Takydromus is estimated using a data set of 35 morphological characters drawn from external features, skeleton and soft-parts. There are two main constituent clades which may be informally recognized as Takydromus s.s. and Platyplacopus. Platyplacopus is subtropical and perhaps relict, whereas Takydromus ranges from temperate to tropical areas. The two clades have different ranges of eggs per clutch. In both of them, elongate forms that climb extensively in flimsy vegetation have evolved and have independently acquired similar features that confer performance advantages in this situation. Interestingly, the order of assembly of tliese features is markedly different.     

Allosteric interference in oncogenic FLI1 and ERG transactions by mithramycins

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Hard-sphere/pseudo-particle modelling (HS-PPM) for efficient and scalable molecular simulation of dilute gaseous flow and transport

Continuum methods are not accurate enough for flows at high Knudsen numbers, whereas rigorous molecular dynamics (MD) methods are too costly for simulations at practical dimensions. Hard-sphere (HS) model is a simplified MD method efficient for dilute gaseous flow but is of poor parallelism due to its event-driven nature, which sets a strong limitation to its large-scale applications. In this work, pseudo-particle modelling, a time-driven modelling approach is coupled with HS model to construct a scalable parallel method capable of simulating flows and transport processes at high Knudsen numbers without losing necessary molecular details in describing their macro-scale behaviours. The method is validated in several classical simulation cases and its performance is evaluated to be favourable. To demonstrate the potential applications of this method, we also simulate the diffusion of small molecules in multi-scale porous media which is related to catalysis, material preparation and micro chemical engineering in the long term.