On the mechanism of thrombin-induced angiogenesis: involvement of alphavbeta3-integrin

Thrombin has been reported to be a potent angiogenic factor both in vitro and in vivo, and many of the cellular effects of thrombin may contribute to activation of angiogenesis. In this report we show that thrombin-treatment of human endothelial cells increases mRNA and protein levels of alphavbeta3-integrin. This thrombin-mediated effect is specific, dose dependent, and requires the catalytic site of thrombin. In addition, thrombin interacts with alphavbeta3 as demonstrated by direct binding of alphavbeta3 protein to immobilized thrombin. This interaction of thrombin with alphavbeta3-integrin, which is an angiogenic marker in vascular tissue, is of functional significance. Immobilized thrombin promotes endothelial cells attachment, migration, and survival. Antibody to alphavbeta3 or a specific peptide antagonist to alphavbeta3 can abolish all these alphavbeta3-mediated effects. Furthermore, in the chick chorioallantoic membrane system, the antagonist peptide to alphavbeta3 diminishes both basal and the thrombin-induced angiogenesis. These results support the pivotal role of thrombin in activation of endothelial cells and angiogenesis and may be related to the clinical observation of neovascularization within thrombi.     

Factors affecting laboratory bioassays with diatomaceous earth on stored wheat: effect of insect density, grain quantity, and cracked kernel containment

Laboratory bioassays were carried out to evaluate the effect of insect density (10, 30, 60, and 100 adults), wheat quantity (10, 30, 60, and 100 g), and cracked kernel containment (5, 15, 30, and 50%) on the efficacy of diatomaceous earth (DE). Three beetle species, Sitophilus oryzae (L.), Rhyzopertha dominica (F.), and Tribolium confusum Jacquelin du Val, as well as two DE formulations, Insecto and SilicoSec, and one DE enhanced with pyrethrum, PyriSec (all commercially available) were tested. In the first two series of bioassays, the three DE formulations were applied at three dose rates, 500, 1000 and 1,500 ppm. In the third series, the dose rates used were 500 and 1,000 ppm. Dead adults were counted 14 d later. For insect density, wheat quantity, and cracked kernel containment, significant differences were noted in mortality levels of the tested species among the three DE formulations and among doses. No significant differences were noted in the mortality levels among the four adult densities of any of the insects tested. The increase of wheat quantity used in the bioassays increased significantly adult mortality of T. confusum. The increase of cracked wheat containment decreased significantly adult mortality of S. oryzae.     

Association of genome variations in the renin-angiotensin system with physical performance

Background

The aim of this study was to determine the genotype distribution and allelic frequencies of ACE (I/D), AGTR1 (A +1166 C), BDKRB2 (+9/?9) and LEP (G–2548A) genomic variations in 175 Greek athletes who excelled at a national and/or international level and 169 healthy Greek adults to identify whether some particular combinations of these loci might serve as predictive markers for superior physical condition.

Results

The D/D genotype of the ACE gene (p = 0.034) combined with the simultaneous existence of BDKRB2 (+9/?9) (p = 0.001) or LEP (G/A) (p = 0.021) genotypes was the most prevalent among female athletes compared to female controls. A statistical trend was also observed in BDKRB2 (+9/?9) and LEP (G–2548A) heterozygous genotypes among male and female Greek athletes, and in ACE (I/D) only in male athletes. Finally, both male and female athletes showed the highest rates in the AGTR1 (A/A) genotype.

Conclusions

Our results suggest that the co-existence of ACE (D/D), BDKRB2 (+9/?9) or LEP (G/A) genotypes in female athletes might be correlated with a superior level of physical performance.

     

Prey‐mediated changes in the selectivity of the predator Macrolophus pygmaeus (Heteroptera: Miridae)

When foraging in communities with mixed prey, generalist predators may be confronted with prey species that differ in quality, size and mobility and interact with one another. To examine prey selection, predation by Macrolophus pygmaeus (Heteroptera: Miridae) was recorded by providing a diet of either one or two prey species of Myzus persicae (third‐instar nymphs), Aphis gossypii (fourth‐instar nymphs), Trialeurodes vaporariorum (third‐instar nymphs) and Ephestia kuehniella (eggs). In the experiments, prey mobility, prey quality and prey biomass were considered. The biomass consumed by the predator was dependent on the combination of prey species and the quantity of biomass offered. In choice experiments with diets mixed of two prey species at equal densities, the predation to A. gossypii was significantly reduced in the presence of E. kuehniella but the rate of consumption of M. persicae, T. vaporariorum and E.kuehniella was not significantly affected by the coexistence of any other species in the mixed prey diet. When equal amounts of biomass from two prey species were provided in combination, the total consumed biomass was significantly reduced in the mixed prey diets composed of E. kuehniella eggs and aphid nymphs. Thus, under the mixed‐prey situation, prey selection by predators may be affected by interactions among prey species differing in traits such as quality, mobility and size.     

Engineered Polyamine Catabolism Preinduces Tolerance of Tobacco to Bacteria and Oomycetes

Polyamine oxidase (PAO) catalyzes the oxidative catabolism of spermidine and spermine, generating hydrogen peroxide. In wild-type tobacco (Nicotiana tabacum ‘Xanthi’) plants, infection by the compatible pathogen Pseudomonas syringae pv tabaci resulted in increased PAO gene and corresponding PAO enzyme activities; polyamine homeostasis was maintained by induction of the arginine decarboxylase pathway and spermine was excreted into the apoplast, where it was oxidized by the enhanced apoplastic PAO, resulting in higher hydrogen peroxide accumulation. Moreover, plants overexpressing PAO showed preinduced disease tolerance against the biotrophic bacterium P. syringae pv tabaci and the hemibiotrophic oomycete Phytophthora parasitica var nicotianae but not against the Cucumber mosaic virus. Furthermore, in transgenic PAO-overexpressing plants, systemic acquired resistance marker genes as well as a pronounced increase in the cell wall-based defense were found before inoculation. These results reveal that PAO is a nodal point in a specific apoplast-localized plant-pathogen interaction, which also signals parallel defense responses, thus preventing pathogen colonization. This strategy presents a novel approach for producing transgenic plants resistant to a broad spectrum of plant pathogens.     

Trend in aliens species in the Mediterranean. An answer to Galil, 2009 «Taking stock: inventory of alien species in the Mediterranean Sea»

The number of marine alien species reported in Galil (Biol Invasions, 2009) is incomplete. Recent literature suggests that the number of aliens is nearly 1,000 and that the introduction rate is way off the 10 species per year suggested by Galil (Biol Invasions, 2009).