Pitcher geometry facilitates extrinsically powered ‘springboard trapping' in carnivorous Nepenthes gracilis pitcher plants

Carnivorous pitcher plants capture insects in cup-shaped leaves that function as motionless pitfall traps. Nepenthes gracilis evolved a unique ‘springboard'' trapping mechanism that exploits the impact energy of falling raindrops to actuate a fast pivoting motion of the canopy-like pitcher lid. We superimposed multiple computed micro-tomography images of the same pitcher to reveal distinct deformation patterns in lid-trapping N. gracilis and closely related pitfall-trapping N. rafflesiana. We found prominent differences between downward and upward lid displacement in N. gracilis only. Downward displacement was characterized by bending in two distinct deformation zones whist upward displacement was accomplished by evenly distributed straightening of the entire upper rear section of the pitcher. This suggests an anisotropic impact response, which may help to maximize initial jerk forces for prey capture, as well as the subsequent damping of the oscillation. Our results point to a key role of pitcher geometry for effective ‘springboard'' trapping in N. gracilis.     

Endothelin-1 Up-Regulates p115RhoGEF in Embryonic Rat Cardiomyocytes During the Hypertrophic Response

In cardiomyocytes, certain extracellular stimuli that activate heterotrimeric G protein-coupled receptors (GPCRs) can induce hypertrophy by regulating gene expression and increasing protein synthesis. We investigated if rat embryonic cardiomyocytes (H9c2) underwent variations in the expression levels and subcellular distribution of key components of GPCR-activated signaling pathways during endothelin-1 (ET-1)-induced hypertrophic response. A significant increase of p115RhoGEF protein level was evident in ET-1-treated cells. Real-time quantitative PCR showed RhoGEF mRNA levels were significantly increased. Inhibition of the Rho-associated kinase (ROCK) caused a significant decrease of p115RhoGEF protein in the nuclear fraction, whereas an inhibitor of PKC induced a redistribution of the protein between membrane/organelle and nuclear fractions. The ROCK inhibitor also decreased H9c2 cell hypertrophic response. These results indicate that ROCK and its downstream target molecules, which are involved in inducing the hypertrophic response, are also implicated in signaling the up-regulation of the p115RhoGEF protein.     

An ethological framework for animal bioerosion trace fossils upon mineral substrates with proposal of a new class, fixichnia

Animal bioerosion trace fossils upon mineral substrates are analyzed from the point of view of the Seilacherian ethological classification. Several of the currently accepted ethological classes: cubichnia, fugichnia, repichnia, fodinichnia, agrichnia, calichnia and aedificichnia are not represented in these substrates. This fact points out a lower behavioral diversity of hard substrate trace fossils when compared with soft sediment trace fossils. Bioerosion traces can be classified in just five classes: domichnia, pascichnia, equilibrichnia, praedichnia and fixichnia. Fixichnia is here erected to gather superficial etching scars resulting from the anchoring of fixation of sessile epiliths by means of a soft or skeletal body part. Praedichnia and fixichnia are exclusive of the bioerosion realm.     

A cryptic invasion within an invasion and widespread introgression in the European water frog complex: consequences of uncontrolled commercial trade and weak international legislation

In Western Europe, many pond owners introduce amphibians for ornamental purposes. Although indigenous amphibians are legally protected in most European countries, retailers are circumventing national and international legislation by selling exotic nonprotected sibling species. We investigated to what extent non‐native species of the European water frog complex (genus Pelophylax) have become established in Belgium, using morphological, mitochondrial and nuclear genetic markers. A survey of 87 sampling sites showed the presence of non‐native water frogs at 47 locations, mostly Marsh frogs (Pelophylax ridibundus). Surprisingly, at least 19% of all these locations also harboured individuals with mitochondrial haplotypes characteristic of Anatolian water frogs (Pelophylax cf. bedriagae). Nuclear genotyping indicated widespread hybridization and introgression between P. ridibundus and P. cf. bedriagae. In addition, water frogs of Turkish origin obtained through a licensed retailer, also contained P. ridibundus and P. cf. bedriagae, with identical haplotypes to the wild Belgian populations. Although P. ridibundus might have invaded Belgium by natural range expansion from neighbouring countries, our results suggest that its invasion was at least partly enhanced by commercial trade, with origins as far as the Middle East. Also the invasion and rapid spread of Anatolian lineages, masked by their high morphological similarity to P. ridibundus, is likely the result of unregulated commercial trade. We expect that Anatolian frogs will further invade the exotic as well as the native range of P. ridibundus and other Pelophylax species elsewhere in Western and Central Europe, with risks of large‐scale hybridization and introgression.     

Two closely linked tomato HKT coding genes are positional candidates for the major tomato QTL involved in Na+/K+ homeostasis

The location of major quantitative trait loci (QTL) contributing to stem and leaf [Na⁺] and [K⁺] was previously reported in chromosome 7 using two connected populations of recombinant inbred lines (RILs) of tomato. HKT1;1 and HKT1;2, two tomato Na⁺‐selective class I‐HKT transporters, were found to be closely linked, where the maximum logarithm of odds (LOD) score for these QTLs located. When a chromosome 7 linkage map based on 278 single‐nucleotide polymorphisms (SNPs) was used, the maximum LOD score position was only 35 kb from HKT1;1 and HKT1;2. Their expression patterns and phenotypic effects were further investigated in two near‐isogenic lines (NILs): 157‐14 (double homozygote for the cheesmaniae alleles) and 157‐17 (double homozygote for the lycopersicum alleles). The expression pattern for the HKT1;1 and HKT1;2 alleles was complex, possibly because of differences in their promoter sequences. High salinity had very little effect on root dry and fresh weight and consequently on the plant dry weight of NIL 157‐14 in comparison with 157‐17. A significant difference between NILs was also found for [K⁺] and the [Na⁺]/[K⁺] ratio in leaf and stem but not for [Na⁺] arising a disagreement with the corresponding RIL population. Their association with leaf [Na⁺] and salt tolerance in tomato is also discussed.