Identification of Contractile Vacuole Proteins in Trypanosoma cruzi

Contractile vacuole complexes are critical components of cell volume regulation and have been shown to have other functional roles in several free-living protists. However, very little is known about the functions of the contractile vacuole complex of the parasite Trypanosoma cruzi, the etiologic agent of Chagas disease, other than a role in osmoregulation. Identification of the protein composition of these organelles is important for understanding their physiological roles. We applied a combined proteomic and bioinfomatic approach to identify proteins localized to the contractile vacuole. Proteomic analysis of a T. cruzi fraction enriched for contractile vacuoles and analyzed by one-dimensional gel electrophoresis and LC-MS/MS resulted in the addition of 109 newly detected proteins to the group of expressed proteins of epimastigotes. We also identified different peptides that map to at least 39 members of the dispersed gene family 1 (DGF-1) providing evidence that many members of this family are simultaneously expressed in epimastigotes. Of the proteins present in the fraction we selected several homologues with known localizations in contractile vacuoles of other organisms and others that we expected to be present in these vacuoles on the basis of their potential roles. We determined the localization of each by expression as GFP-fusion proteins or with specific antibodies. Six of these putative proteins (Rab11, Rab32, AP180, ATPase subunit B, VAMP1, and phosphate transporter) predominantly localized to the vacuole bladder. TcSNARE2.1, TcSNARE2.2, and calmodulin localized to the spongiome. Calmodulin was also cytosolic. Our results demonstrate the utility of combining subcellular fractionation, proteomic analysis, and bioinformatic approaches for localization of organellar proteins that are difficult to detect with whole cell methodologies. The CV localization of the proteins investigated revealed potential novel roles of these organelles in phosphate metabolism and provided information on the potential participation of adaptor protein complexes in their biogenesis

Cancer Biomarker Discovery: The Entropic Hallmark

Background: It is a commonly accepted belief that cancer cells modify their transcriptional state during the progression of the disease. We propose that the progression of cancer cells towards malignant phenotypes can be efficiently tracked using high-throughput technologies that follow the gradual changes observed in the gene expression profiles by employing Shannon's mathematical theory of communication. Methods based on Information Theory can then quantify the divergence of cancer cells' transcriptional profiles from those of normally appearing cells of the originating tissues. The relevance of the proposed methods can be evaluated using microarray datasets available in the public domain but the method is in principle applicable to other high-throughput methods. Methodology/Principal Findings: Using melanoma and prostate cancer datasets we illustrate how it is possible to employ Shannon Entropy and the Jensen-Shannon divergence to trace the transcriptional changes progression of the disease. We establish how the variations of these two measures correlate with established biomarkers of cancer progression. The Information Theory measures allow us to identify novel biomarkers for both progressive and relatively more sudden transcriptional changes leading to malignant phenotypes. At the same time, the methodology was able to validate a large number of genes and processes that seem to be implicated in the progression of melanoma and prostate cancer. Conclusions/Significance: We thus present a quantitative guiding rule, a new unifying hallmark of cancer: the cancer cell's transcriptome changes lead to measurable observed transitions of Normalized Shannon Entropy values (as measured by high-throughput technologies). At the same time, tumor cells increment their divergence from the normal tissue profile increasing their disorder via creation of states that we might not directly measure. This unifying hallmark allows, via the the Jensen-Shannon divergence, to identify the arrow of time of the processes from the gene expression profiles, and helps to map the phenotypical and molecular hallmarks of specific cancer subtypes. The deep mathematical basis of the approach allows us to suggest that this principle is, hopefully, of general applicability for other diseases

Assessment of the nasolabial angle in young Brazilian black subjects with normal occlusion Verificação do ângulo nasolabial em jovens brasileiros melanodermas com oclusão normal

Black individuals present craniofacial characteristics which differ from those of other races, especially the white race, whose cephalometric analyses are usually considered as the standard in routine orthodontic diagnosis and treatment planning. Further studies are therefore needed to enable more accurate and specific diagnoses for this ethnic group. The present study was conducted in order to assess average values for the nasolabial angle in young Brazilian black individuals with normal occlusion, and to assess the occurence of sexual dimorphism. Thirty-six lateral skull, extraoral radiographs from Brazilian black individuals were selected from the archives of the Scientific Recordings Department, Orthodontics Graduate Program, School of Dentistry of Piracicaba, State University of Campinas (UNICAMP). The patients' ages varied from 10 to 14 years, they presented normal occlusion upon clinical examination, and had not been submitted to orthodontic treatment. The cephalometric landmarks from which the nasolabial angle was obtained and measured were traced by a single researcher. Statistical analysis and evaluation of the results led to the conclusion that the nasolabial angle of young Brazilian black individuals is sharper, i.e., the soft tissue profile is more protruded. The average value for the whole sample was 88.14º ± 12.52º. The nasolabial angle was statistically smaller among females (p < 0.05), demonstrating the occurrence of sexual dimorphism.<br>Os indivíduos melanodermas possuem características craniofaciais diferentes das apresentadas pelas demais raças, principalmente por leucodermas que, normalmente, são considerados como padrão nas análises cefalométricas utilizadas rotineiramente no diagnóstico e planejamento dos tratamentos ortodônticos. São, portanto, necessárias novas pesquisas que permitam um diagnóstico mais acurado e específico para esse grupo étnico. Os pesquisadores desenvolveram esta pesquisa com o objetivo de verificar valores médios do ângulo nasolabial em jovens melanodermas brasileiros com oclusão clinicamente normal e de verificar a ocorrência de dimorfismo sexual. Foram selecionadas 36 telerradiografias de cabeça, tomadas em norma lateral, de indivíduos brasileiros melanodermas, na faixa etária de 10 a 14 anos, de ambos os sexos, com oclusão clinicamente normal e que nunca se submeteram a tratamento ortodôntico, provenientes dos arquivos do Setor de Documentação Científica do Curso de Pós-Graduação em Ortodontia da Faculdade de Odontologia de Piracicaba da Universidade Estadual de Campinas. Sobre essas radiografias foram delimitados os pontos e as linhas que dão origem ao ângulo nasolabial, o qual foi traçado e medido por um único pesquisador. Após análise estatística e avaliação dos resultados, concluiu-se que o ângulo nasolabial em indivíduos jovens brasileiros melanodermas apresenta-se mais agudo, ou seja, o perfil tegumentar apresenta-se mais protruso. Os valor médio obtido para a amostra toda foi 88,14º ± 12,52º. O ângulo nasolabial foi estatisticamente menor no sexo feminino (p < 0,05), demonstrando a existência de dimorfismo sexual