Influence of feeding habits in the endocrine pancreas of insectivore bat Pteronotus personatus and nectarivore bat Anoura geoffroyi: A comparative stereological and immunohistochemical study

Pteronotus personatus as an insectivore bat and has a diet that consists of a high protein diet, whereas the diet of Anoura geoffroyi, a predominantly nectarivore bat, is rich in simple sugars like sucrose, glucose and fructose. Considering that diet influences the activation of different pathways, which may influence morphological adaptations in the gastrointestinal system, the aim of this study was to compare the morphology of the endocrine pancreas in P. personatus and A. geoffroyi. For this, histological, stereological and immunohistochemical methods were used. In P. personatus, the average diameter of the pancreatic islet was 40.47 μm ± 13.94, while in A. geoffroyi was 88.16 μm ± 36.40. The total number of pancreatic islets in P. personatus was 26150 ± 2346 and in A. geoffroyi was 15970 ± 1666. In P. personatus, the volume density of the pancreatic islets was 3.4%± 2.6, whereas in A. geoffroyi the volume density was 6.1% ± 3.7. In addition, the immunodensity of the α, β and δ cells, in P. personatus was 25.8% ± 11.9, 35.5% ± 13.5, 3.9% ± 0.7, respectively, and in A. geoffroyi was 33.10% ± 12.7, 55.08% ± 7.4, 6.2% ± 4.6, respectively. In conclusion, the results of this study indicate differences in the pancreatic weight/body, weight ratio, diameter and volume density of pancreatic islets and in immunodensity of the β and α cells between both species, which have different dietary habits.     

Isolation of low-pathogenic H7N3 avian influenza from wild birds in Peru

Wild birds serve as natural reservoirs and sometimes harbor low-pathogenic avian influenza viruses. However, mutation of the virus can result in highly pathogenic strains, often more common among H5 and H7 genotypes. We report the isolation of a low-pathogenic H7N3 avian influenza in a Peruvian wetland.     

IGF2 derived from SH-SY5Y neuroblastoma cells induces the osteoclastogenesis of human monocytic precursors

The insulin-like growth factors 2 (IGF2) is a peptide hormone that binds to the insulin-like growth factor 1 receptor (IGF1R) and is abundantly stored in bone. IGF1R is deeply involved in the pathogenesis of many cancers that growth within bone and is also involved in osteoclast biology. Among different cell lines representative of osteolytic tumors, we found a very high expression of IGF2 in SH-SY5Y cells derived from neuroblastoma (NB). We previously showed that NB cells induce an osteolytic process through the Osteoprotegerin/RANKL/RANK and the canonical Wnt pathway system. Here, we hypothesized that NB promotes osteoclastogenesis also via IGF2. First, we demonstrated the presence of IGF1R on the osteoclast basolateral membrane, and we observed a cyclic IGF1R activation along with the differentiation process, also when induced by SH-SY5Y. Moreover, we found that IGF2 mRNA expression in SH-SY5Y cells was further increased when co-cultured with mesenchymal stromal cells, suggesting that IGF2 is important for NB interaction with the bone microenvironment. Finally, the treatment of SH-SY5Y cells with an anti-IGF2 siRNA or the addition of anti-IGF1R molecules impaired NB-induced osteoclastogenesis, even though the chemoattraction of monocytes by NB cells was unaffected. Our findings suggest that in IGF2-producing osteolytic tumors IGF1R is a good candidate for targeted therapies in combination with conventional drugs.     

T-cell receptor Vβ repertoire of CD8+ T-lymphocyte subpopulations in cutaneous leishmaniasis patients from the state of Rio de Janeiro, Brazil

In human cutaneous leishmaniasis (CL), the immune response is mainly mediated byT-cells. The role of CD8⁺ T-lymphocytes, which are related to healing ordeleterious functions, in affecting clinical outcome is controversial. The aim ofthis study was to evaluate T-cell receptor diversity in late-differentiated effector(LDE) and memory CD8⁺ T-cell subsets in order to create a profile ofspecific clones engaged in deleterious or protective CL immune responses. Healthysubjects, patients with active disease (PAD) and clinically cured patients wereenrolled in the study. Total CD8⁺ T-lymphocytes showed a disturbance inthe expression of the Vβ2, Vβ9, Vβ13.2, Vβ18 and Vβ23 families. The analyses ofCD8⁺T-lymphocyte subsets showed high frequencies of LDECD8⁺T-lymphocytes expressing Vβ12 and Vβ22 in PAD, as well aseffector-memory CD8⁺ T-cells expressing Vβ22. We also observed lowfrequencies of effector and central-memory CD8⁺ T-cells expressing Vβ2 inPAD, which correlated with a greater lesion size. Particular Vβ expansions point toCD8⁺ T-cell clones that are selected during CL immune responses,suggesting that CD8⁺ T-lymphocytes expressing Vβ12 or Vβ22 are involved ina LDE response and that Vβ2 contractions in memory CD8⁺T-cells areassociated with larger lesions.     

Assessing the genetic diversity of Panicum coloratum var. makarikariense using agro‐morphological traits and microsatellite‐based markers

Panicum coloratum var. makarikariense is a perennial C₄ grass native to South Africa with relatively good forage production under limited‐resource conditions. Genetic characterisation and breeding efforts have been scant, thus limiting its use in cattle raising systems. The goal of the present study was to assess the genetic diversity of a collection of P. coloratum var. makarikariense using agro‐morphological traits and molecular markers, in comparison with one accession of var. coloratum and one population of Panicum bergii. Agro‐morphological variability between and within accessions of var. makarikariense in a common garden setting was observed, showing that there is still opportunity for selection. Some accessions performed better than the commercialised material in relation to potential forage production. A total of 117 ISSR bands and 48 SSR alleles allowed the detection of genetic variability between and within accessions. The presence of accession‐specific bands suggested distinctness and limited gene flow. The genetic variability encountered in the commercialised material suggested that it is a stabilised population which has not undergone a strong selection process. Low correlation between agro‐morphologic and molecular variability was observed indicating that both approaches provide complementary information. Both morphological and molecular markers reveal genetic differentiation between varieties and species. This study provides a set of new SSR markers available for diversity assessment and valuable information that can be applied directly in collection management for breeding and conservation programmes.     

NAADP mobilizes Ca(2+) from reserve granules,lysosome-related organelles,in sea urchin eggs

Nicotinic acid adenine dinucleotide phosphate (NAADP) mobilizes Ca(2+) in many cells and species. Unlike other Ca(2+)-mobilizing messengers, NAADP mobilizes Ca(2+) from an unknown store that is not the endoplasmic reticulum, the store traditionally associated with messenger-mediated Ca(2+) signaling. Here, we demonstrate the presence of a Ca(2+) store in sea urchin eggs mobilized by NAADP that is dependent on a proton gradient maintained by an ATP-dependent vacuolar-type proton pump. Moreover, we provide pharmacological and biochemical evidence that this Ca(2+) store is the reserve granule, the functional equivalent of a lysosome in the sea urchin egg. These findings represent an unsuspected mechanism for messenger-mediated Ca(2+) release from lysosome-related organelles.     

Allelic diversity for neutral markers retains a higher adaptive potential for quantitative traits than expected heterozygosity

The adaptive potential of a population depends on the amount of additive genetic variance for quantitative traits of evolutionary importance. This variance is a direct function of the expected frequency of heterozygotes for the loci which affect the trait (QTL). It has been argued, but not demonstrated experimentally, that long‐term response to selection is more dependent on QTL allelic diversity than on QTL heterozygosity. Conservation programmes, aimed at preserving this variation, usually rely on neutral markers rather than on quantitative traits for making decisions on management. Here, we address, both through simulation analyses and experimental studies with Drosophila melanogaster, the question of whether allelic diversity for neutral markers is a better indicator of a high adaptive potential than expected heterozygosity. In both experimental and simulation studies, we established synthetic populations for which either heterozygosity or allelic diversity was maximized using information from QTL (simulations) or unlinked neutral markers (simulations and experiment). The synthetic populations were selected for the quantitative trait to evaluate the evolutionary potential provided by the two optimization methods. Our results show that maximizing the number of alleles of a low number of markers implies higher responses to selection than maximizing their heterozygosity.     

Perturbation of the dimer interface of triosephosphate isomerase and its effect on Trypanosoma cruzi

Background

Chagas disease affects around 18 million people in the American continent. Unfortunately, there is no satisfactory treatment for the disease. The drugs currently used are not specific and exert serious toxic effects. Thus, there is an urgent need for drugs that are effective. Looking for molecules to eliminate the parasite, we have targeted a central enzyme of the glycolytic pathway: triosephosphate isomerase (TIM). The homodimeric enzyme is catalytically active only as a dimer. Because there are significant differences in the interface of the enzymes from the parasite and humans, we searched for small molecules that specifically disrupt contact between the two subunits of the enzyme from Trypanosoma cruzi but not those of TIM from Homo sapiens (HTIM), and tested if they kill the parasite.

Methodology/Principal Findings

Dithiodianiline (DTDA) at nanomolar concentrations completely inactivates recombinant TIM of T. cruzi (TcTIM). It also inactivated HTIM, but at concentrations around 400 times higher. DTDA was also tested on four TcTIM mutants with each of its four cysteines replaced with either valine or alanine. The sensitivity of the mutants to DTDA was markedly similar to that of the wild type. The crystal structure of the TcTIM soaked in DTDA at 2.15 Å resolution, and the data on the mutants showed that inactivation resulted from alterations of the dimer interface. DTDA also prevented the growth of Escherichia coli cells transformed with TcTIM, had no effect on normal E. coli, and also killed T. cruzi epimastigotes in culture.

Conclusions/Significance

By targeting on the dimer interface of oligomeric enzymes from parasites, it is possible to discover small molecules that selectively thwart the life of the parasite. Also, the conformational changes that DTDA induces in the dimer interface of the trypanosomal enzyme are unique and identify a region of the interface that could be targeted for drug discovery.     

Aporphine alkaloids from Phoebe pittieri

The wood and bark of Phoebe pittieri afforded 1,2,3-trimethoxy-9,10-methylenedioxynoraporphine and 1,2,9-trimethoxy-10-hydroxynoraporphine (noraporphine), which are new alkaloids, and norpurpureine and reticuline, which have not been reported from this source before.