A new species of Thrissina from Pakistan (Arabian Sea), with redescription of Thrissina whiteheadi (Wongratana 1983) (Clupeiformes: Engraulidae)

Ichthyological Research - Thrissina supra sp. nov. is described based on 15 specimens collected from Sindh, Pakistan. The new species is closely related to Thrissina whiteheadi (Wongratana 1983),...     

Isolation of a novel neutralizing antibody fragment against human vascular endothelial growth factor from a phage-displayed human antibody repertoire using an epitope disturbing strategy

Following the clinical success of Bevacizumab, a humanized monoclonal antibody that blocks the interaction between vascular endothelial growth factor (VEGF) and its receptors, the search for new neutralizing antibodies targeting this molecule has continued until now. We used a human VEGF variant containing three mutations in the region recognized by Bevacizumab to direct antibody selection towards recognition of other epitopes. A total of seven phage-displayed antibody fragments with diverse binding properties in terms of inter-species cross-reactivity and sensitivity to chemical modifications of the antigen were obtained from a human phage display library. All of them were able to recognize not only the selector mutated antigen, but also native VEGF. One of these phage-displayed antibody fragments, denominated 2H1, was shown to compete with the VEGF receptor 2 for VEGF binding. Purified soluble 2H1 inhibited in a dose dependent manner the ligand-receptor interaction and abolished VEGF-dependent proliferation of human umbilical vein endothelial cells. Our epitope disturbing strategy based on a triple mutant target antigen was successful to focus selection on epitopes different from a known one. Similar approaches could be used to direct phage isolation towards the desired specificity in other antigenic systems.     

Tamoxifen treatment induces protection in murine cysticercosis

Administration of tamoxifen (an antiestrogen) produced an 80% parasite load reduction in female mice, and a weaker effect of 50% in male mice. This protective effect was associated in both sexes, with an increase in the mRNA levels of interleukin (IL)-2 (a cytokine associated with protection against cysticerci) and IL-4 (no effect on infection). tamoxifen treatment modified 17-beta estradiol production in females, whereas serum testosterone was not affected. However, the expression of the 2 types of estrogen receptor (ER), i.e., ER-alpha and ER-beta, in the spleen of infected mice of both sexes, was decreased by tamoxifen treatment. In vitro, treatment of Taenia crassiceps with tamoxifen reduced reproduction and loss of motility. These results indicate that tamoxifen treatment is a new therapeutic possibility to treat cysticercosis, because it can act at both ends of the host-parasite relationship, i.e., by increasing the cellular immune response protective against the parasite and by directly affecting the parasite's reproduction and survival.     

Gender differences in ancestral contribution and admixture in Venezuelan populations

The origin of the contribution of uniparental heritage were analyzed in 615 samples of individuals proceeding from 13 towns classified according to historic differences in their emergence and development as African-derived, European-derived, and admixed/urban. Mitochondrial and Y-chromosome haplogroups were identified by PCR-restriction fragment length polymorphism. The results were compared with previous estimates of admixture made with autosomal markers and with historic aspects. The results show a predominantly indigenous genetic contribution through the female, being more prevalent in urban populations; the African contribution, although dispersed, presents a larger concentration in the African-derived towns, whereas the European contribution is limited to populations with this origin, reflecting isolation and the conservation of the distribution pattern of genes of the Colonial era. With regard to admixture through males, it is almost exclusively of European origin, whereas the African contribution is basically concentrated in the African-derived towns, and the Amerindian lineages are almost nonexistent. The genome of paternal heredity, as opposed to the autosomal and the mitochondrial, shows a homogeneous pattern of admixture that is independent of the origin of the population studied, suggesting that European genes have been introduced into the Venezuelan population through male immigrations, whereas the indigenous contribution has been preserved in the Venezuelan genetic pool through the women. These results provide evidence of the heterogeneity in the genetic origin of the Venezuelan population, which should be taken into account in forensic and epidemiologic genetic studies.     

Inhibitory role of antibodies in the development of Taenia solium and Taenia crassiceps toward reproductive and pathogenic stages.

Untreated Taenia solium cysticerci obtained from different naturally infected pigs vary notably in their capacity to develop into intestinal tapeworms in prednisolone-treated hamsters, whereas cells derived from Taenia crassiceps cysticerci after 2 mo of infection almost always develop to cysticerci in the peritoneal cavity of susceptible BALB/cAnN mice. Preincubation of whole cysticerci or parasite cells with mice immunoglobulins raised against an 18-mer peptide epitope (GK-1) common to both parasites significantly interferes with both transformations. These crippling effects of antiparasite antibodies suggest new forms of immunological interference with parasite biology other than simple killing. Antibodies that cripple biological functions of the parasite, e.g., their development to reproductive or pathogenic stages, make them important protagonists in taeniasis/cysticercosis disease as classic parasitocidal antibodies. Different serum levels of crippling antibodies in the infected pigs could be responsible for the varied ability of cysticerci to convert to tapeworms. Antigens capable of inducing crippling antibodies, e.g., GK-1, could be useful as a therapeutic vaccine for pigs in order to reduce parasite transmission.     

Homeorrhetic modifications produced by a beta-agonist in the muscle and adipose tissues of the rat]

A repartitioning effect was observed in young rats after a chronic treatment with a nonselective beta-agonist administered subcutaneously. An increase in carcass protein (P less than 0.05) accompanied by a reduction in fat stores (P less than 0.01) and an increase in back fat oxygen consumption (P less than 0.05) were found in treated animals. The muscle mass accretion should be attributed to a reduction in muscle protein degradation, based on lower activity of the proteolytic enzyme cathepsin A in treated rats, rather than to changes in protein synthesis, assessed by an amino-acid incorporation technique. The anabolic actions of this compound apparently involve changes in muscle prostaglandin E2 and reduction-oxidation state.     

IC50 of trifluoperazine and RMI 12330A for the theophylline and phloretin-induced increase in intestinal D-galactose accumulation

The effect of trifluoperazine and RMI 12330A on D-Galactose accumulation was studied in isolated rat intestinal mucosa. Both drugs inhibited the theophylline and phloretin-induced increase in tissue sugar accumulation in a concentration-dependent fashion, with IC50 values close to 10(-6) M. These findings suggest that calmodulin might mediate the theophylline and phloretin actions on galactose transport in intact rat ileum.     

Scale-free foraging by primates emerges from their interaction with a complex environment

Scale-free foraging patterns are widespread among animals. These may be the outcome of an optimal searching strategy to find scarce, randomly distributed resources, but a less explored alternative is that this behaviour may result from the interaction of foraging animals with a particular distribution of resources. We introduce a simple foraging model where individual primates follow mental maps and choose their displacements according to a maximum efficiency criterion, in a spatially disordered environment containing many trees with a heterogeneous size distribution. We show that a particular tree-size frequency distribution induces non-Gaussian movement patterns with multiple spatial scales (Lévy walks). These results are consistent with field observations of tree-size variation and spider monkey (Ateles geoffroyi) foraging patterns. We discuss the consequences that our results may have for the patterns of seed dispersal by foraging primates.