Genome of the Avirulent Human-Infective Trypanosome—Trypanosoma rangeli

Background: Trypanosoma rangeli is a hemoflagellate protozoan parasite infecting humans and other wild and domestic mammals across Central and South America. It does not cause human disease, but it can be mistaken for the etiologic agent of Chagas disease, Trypanosoma cruzi. We have sequenced the T. rangeli genome to provide new tools for elucidating the distinct and intriguing biology of this species and the key pathways related to interaction with its arthropod and mammalian hosts.  Methodology/Principal Findings: The T. rangeli haploid genome is ,24 Mb in length, and is the smallest and least repetitive trypanosomatid genome sequenced thus far. This parasite genome has shorter subtelomeric sequences compared to those of T. cruzi and T. brucei; displays intraspecific karyotype variability and lacks minichromosomes. Of the predicted 7,613 protein coding sequences, functional annotations could be determined for 2,415, while 5,043 are hypothetical proteins, some with evidence of protein expression. 7,101 genes (93%) are shared with other trypanosomatids that infect humans. An ortholog of the dcl2 gene involved in the T. brucei RNAi pathway was found in T. rangeli, but the RNAi machinery is non-functional since the other genes in this pathway are pseudogenized. T. rangeli is highly susceptible to oxidative stress, a phenotype that may be explained by a smaller number of anti-oxidant defense enzymes and heatshock proteins.  Conclusions/Significance: Phylogenetic comparison of nuclear and mitochondrial genes indicates that T. rangeli and T. cruzi are equidistant from T. brucei. In addition to revealing new aspects of trypanosome co-evolution within the vertebrate and invertebrate hosts, comparative genomic analysis with pathogenic trypanosomatids provides valuable new information that can be further explored with the aim of developing better diagnostic tools and/or therapeutic targets

Molecular Characterization of TP53 Gene in Human Populations Exposed to Low-Dose Ionizing Radiation

Ionizing radiation, such as that emitted by uranium, may cause mutations and consequently lead to neoplasia in human cells. The TP53 gene acts to maintain genomic integrity and constitutes an important biomarker of susceptibility. The present study investigated the main alterations observed in exons 4, 5, 6, 7, and 8 of the TP53 gene and adjacent introns in Amazonian populations exposed to radioactivity. Samples were collected from 163 individuals. Occurrence of the following alterations was observed: (i) a missense exchange in exon 4 (Arg72Pro); (ii) 2 synonymous exchanges, 1 in exon 5 (His179His), and another in exon 6 (Arg213Arg); (iii) 4 intronic exchanges, 3 in intron 7 (C → T at position 13.436; C → T at position 13.491; T → G at position 13.511) and 1 in intron 8 (T → G at position 13.958). Alteration of codon 72 was found to be an important risk factor for cancer development (P=0.024; OR=6.48; CI: 1.29–32.64) when adjusted for age and smoking. Thus, TP53 gene may be an important biomarker for carcinogenesis susceptibility in human populations exposed to ionizing radiation

Molecular characterization of TP53 gene in human populations exposed to low-dose Ionizing radiation

Ministério da Saúde. Secretaria de Vigilância em Saúde. Instituto Evandro Chagas. Ananindeua, PA, Brasil / Federal University of Pará. Biological Sciences Institute. Laboratory of Human and Medical Genetics. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Laboratory of Human and Medical Genetics. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Laboratory of Human and Medical Genetics. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Laboratory of Human and Medical Genetics. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Human Cytogenetics Laboratory. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Human Cytogenetics Laboratory. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Laboratory of Human and Medical Genetics. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Human Cytogenetics Laboratory. Belém, PA, Brazil.Federal University of Pará. Biological Sciences Institute. Laboratory of Human and Medical Genetics. Belém, PA, Brazil.Ionizing radiation, such as that emitted by uranium, may cause mutations and consequently lead to neoplasia in human cells. The TP53 gene acts to maintain genomic integrity and constitutes an important biomarker of susceptibility. The present study investigated themain alterations observed in exons 4, 5, 6, 7, and 8 of the TP53 gene and adjacent introns in Amazonian populations exposed to radioactivity. Samples were collected from 163 individuals. Occurrence of the following alterations was observed: (i) a missense exchange in exon 4 (Arg72Pro); (ii) 2 synonymous exchanges, 1 in exon 5 (His179His), and another in exon 6 (Arg213Arg); (iii) 4 intronic exchanges, 3 in intron 7 (C - T at position 13.436; C - T at position 13.491; T - G at position 13.511) and 1in intron 8 (T - G at position 13.958). Alteration of codon 72 was found to be an important risk factor for cancer development (P = 0.024; OR = 6.48; CI: 1.29¨C32.64) when adjusted for age and smoking.Thus, TP53 gene may be an important biomarker for carcinogenesis susceptibility in human populations exposed to ionizing radiation

Association of free amino acids with caries experience and mutans streptococci levels in whole saliva of children with early childhood caries

Objective: The aim of the present study was to identify the free amino acid content in whole saliva of children with (CE) and without early childhood caries (CF) (ECC), correlating these findings with caries experience and mutans streptococci (MS) levels in saliva.Design: Seventy-eight healthy children, both genders, 6-71 months age, were selected to participate in the study. Following examination for dmft scores calculation, unstimulated whole saliva was collected from all 78 participants, stored at -80 degrees C, and used for amino acid analysis, on a Biochem 20 plus amino acid analyzer. Stimulated whole saliva was collected from 52 children, transported, diluted and plated on MSB agar medium for detection of MS in cfu/mL.Results: Forty different free amino acids were identified in whole saliva, with great variation in their concentration. A statistically significant relation was found between caries experience and the presence of free proline and glycine. While proline (p = 0.0182) was more frequently absent in the CF group, the absence of glycine (p = 0.0397) was more often observed in the CE group. In the presence of higher levels of MS, free glycine reduced the risk of experiencing dental caries (p = 0.0419). Conversely, the presence of proline was found to increase the risk of experiencing the disease (p = 0.0492).Conclusions: The presence of free proline and absence of free glycine in children with ECC, highly contaminated with MS, increased the chances of experiencing dental caries in the present population. Further studies are needed to better understand this phenomenon. (C) 2008 Elsevier Ltd. All rights reserved

Zika Virus Infects, Activates, and Crosses Brain Microvascular Endothelial Cells, without Barrier Disruption

Zika virus (ZIKV) has been associated to central nervous system (CNS) harm, and virus was detected in the brain and cerebrospinal fluids of microcephaly and meningoencephalitis cases. However, the mechanism by which the virus reaches the CNS is unclear. Here, we addressed the effects of ZIKV replication in human brain microvascular endothelial cells (HBMECs), as an in vitro model of blood brain barrier (BBB), and evaluated virus extravasation and BBB integrity in an in vivo mouse experimental model. HBMECs were productively infected by African and Brazilian ZIKV strains (ZIKVMR766 and ZIKVPE243), which induce increased production of type I and type III IFN, inflammatory cytokines and chemokines. Infection with ZIKVMR766 promoted earlier cellular death, in comparison to ZIKVPE243, but infection with either strain did not result in enhanced endothelial permeability. Despite the maintenance of endothelial integrity, infectious virus particles crossed the monolayer by endocytosis/exocytosis-dependent replication pathway or by transcytosis. Remarkably, both viruses' strains infected IFNAR deficient mice, with high viral load being detected in the brains, without BBB disruption, which was only detected at later time points after infection. These data suggest that ZIKV infects and activates endothelial cells, and might reach the CNS through basolateral release, transcytosis or transinfection processes. These findings further improve the current knowledge regarding ZIKV dissemination pathways

Natural regeneration in abandoned fields following intensive agricultural land use in an Atlantic Forest Island, Brazil

The time required to regrowth a forest in degraded areas depends on how the forest is removed and on the type of land use following removal. Natural regeneration was studied in abandoned old fields after intensive agricultural land use in areas originally covered by Brazilian Atlantic Forests of the Anchieta Island, Brazil in order to understand how plant communities reassemble following human disturbances as well as to determine suitable strategies of forest restoration. The fields were classified into three vegetation types according to the dominant plant species in: 1) Miconia albicans (Sw.) Triana (Melastomataceae) fields, 2) Dicranopteris flexuosa (Schrader) Underw. (Gleicheniaceae) thickets, and 3) Gleichenella pectinata (Willd.) Ching. (Gleicheniaceae) thickets. Both composition and structure of natural regeneration were compared among the three dominant vegetation types by establishing randomly three plots of 1 x 3 m in five sites of the island. A gradient in composition and abundance of species in natural regeneration could be observed along vegetation types from Dicranopteris fern thickets to Miconia fields. The gradient did not accurately follow the pattern of spatial distribution of the three dominant vegetation types in the island regarding their proximity of the remnant forests. A complex association of biotic and abiotic factors seems to be affecting the seedling recruitment and establishment in the study plots. The lowest plant regeneration found in Dicranopteris and Gleichenella thickets suggests that the ferns inhibit the recruitment of woody and herbaceous species. Otherwise, we could not distinguish different patterns of tree regeneration among the three vegetation types. Our results showed that forest recovery following severe anthropogenic disturbances is not direct, predictable or even achievable on its own. Appropriated actions and methods such as fern removal, planting ground covers, and enrichment planting with tree species were suggested in order to restore the natural forest regeneration process in the abandoned old fields

Competência social de psicóticos: o comportamento de olhar nas fases de escuta e de elocução de interações sociais Social skills of psychotics: gaze during the listening and talking phases of social interactions

Investigou-se o comportamento de olhar nas fases de escuta e elocução de interações sociais de 35 pacientes psicóticos comparativamente a 35 sujeitos não-clínicos. Dois observadores treinados observaram os sujeitos em 4 situações sociais de fazer e receber críticas, em desempenho de papéis, gravados em vídeo. Variou-se o tipo de situação e o gênero do interlocutor. Os resultados mostraram maior duração e freqüência de olhar o interlocutor e maior fixidez do olhar no grupo dos pacientes. Ambos os grupos olharam mais o interlocutor na escuta do que na elocução, tal como esperado, tendo os pacientes discriminado menos as fases. Ambos os grupos olharam menos para o interlocutor aos receber do que ao fazer críticas e olharam menos para o interlocutor masculino do que feminino. Estes resultados replicam dados de outros pesquisadores e sugerem uma dificuldade dos pacientes em processos cognitivos envolvidos nas interações sociais e resolução de problemas.<br>This research investigated the characteristics of gaze in the listening and talking phases of social interactions, for 35 psychotics compared to 35 non-clinical subjects. Two judges observed them interacting with trained partners in 4 videotaped role-play situations, regarding giving and receiving criticism. Types of situations and gender of partners were varied. Results showed significant greater duration and frequencies of gaze and more fixed gaze in patients group. Both groups looked more to the partner during listening than talking phase of the interactions, as expected, the patients discriminating less between phases. Both groups looked less in the situations were they have been criticized than in situations where they criticized the partners. Both groups looked less when interacting with male partner, specially the patients. These results in general replicated data from other researchers and indicated which specific dimensions of looking need to be addressed in social skills training for psychiatric patients