Avian erythrocytes have functional mitochondria, opening novel perspectives for birds as animal models in the study of ageing.

BACKGROUND: In contrast to mammalian erythrocytes, which have lost their nucleus and mitochondria during maturation, the erythrocytes of almost all other vertebrate species are nucleated throughout their lifespan. Little research has been done however to test for the presence and functionality of mitochondria in these cells, especially for birds. Here, we investigated those two points in erythrocytes of one common avian model: the zebra finch (Taeniopygia guttata). RESULTS: Transmission electron microscopy showed the presence of mitochondria in erythrocytes of this small passerine bird, especially after removal of haemoglobin interferences. High-resolution respirometry revealed increased or decreased rates of oxygen consumption by erythrocytes in response to the addition of respiratory chain substrates or inhibitors, respectively. Fluorometric assays confirmed the production of mitochondrial superoxide by avian erythrocytes. Interestingly, measurements of plasmatic oxidative markers indicated lower oxidative stress in blood of the zebra finch compared to a size-matched mammalian model, the mouse. CONCLUSIONS: Altogether, those findings demonstrate that avian erythrocytes possess functional mitochondria in terms of respiratory activities and reactive oxygen species (ROS) production. Interestingly, since blood oxidative stress was lower for our avian model compared to a size-matched mammalian, our results also challenge the idea that mitochondrial ROS production could have been one actor leading to this loss during the course of evolution. Opportunities to assess mitochondrial functioning in avian erythrocytes open new perspectives in the use of birds as models for longitudinal studies of ageing via lifelong blood sampling of the same subjects.

Pelecitus helicinus Railliet & Henry, 1910 (Filarioidea, Dirofilariinae) and Other Nematode Parasites of Brazilian Birds

We report Pelecitus helicinus Railliet & Henry, 1910 from 13 species of birds of 2 orders and 7 families, collected from the states of São Paulo and Mato Grosso, Brazil. All 13 constitute new host records for this nematode. In addition, we report the first record of Aprocta golvani Diaz-Ungria, 1963 from Brazil and Monasa nigrifrons (Bucconidae), as well as a number of other nematode records from Neotropical birds.

Tropical cyclones as a critical phenomenon

It has been proposed that the number of tropical cyclones as a function of the energy they release is a decreasing power-law function, up to a characteristic energy cutoff determined by the spatial size of the ocean basin in which the storm occurs. This means that no characteristic scale exists for the energy of tropical cyclones, except for the finite-size effects induced by the boundaries of the basins. This has important implications for the physics of tropical cyclones. We discuss up to what point tropical cyclones are related to critical phenomena (in the same way as earthquakes, rainfall, etc.), providing a consistent picture of the energy balance in the system. Moreover, this perspective allows one to visualize more clearly the effects of global warming on tropical-cyclone occurrence.

Ixodes (Multidentatus) paranaensis n. sp. (Acari: Ixodidae) a parasite of Streptoprocne biscutata (Sclater 1865) (Apodiformes: Apodidae) birds in Brazil

During an ecological study, carried out between 1994 and 1996 with Streptoprocne biscutata (Sclater) (Apodiformes: Apodidae) birds, that inhabit caves in the Quatro Barras County, State of Paraná, Southern Brazil, a new tick species of the subgenus Multidentatus was observed. The female, male, nymph, and larva of Ixodes (Multidentatus) paranaensis n. sp., are described. Of the 12 known species of the subgenus Multidentatus, only I. (M.) auritulus Neumann, 1904 and I. (M.) murreleti Cooley and Kohls, 1945 occur in the Neartic region and only I. (M.) auritulus occurs in the Neotropical region. As such, I. (M.) paranaensis n. sp. increases the number of species and the distribution area of the subgenus Multidentatus in the Americas.

Horizontal stratification of the sand fly fauna (Diptera: Psychodidae) in a transitional vegetation between caatinga and tropical rain forest, state of Bahia, Brazil

A study about the horizontal stratification of the sand fly fauna in two distinct ecosystems, caatinga area, endemic for visceral leishmaniasis, and the tropical rain forest area, endemic for cutaneous leishmaniasis, was performed in the state of Bahia, Brazil. Lutzomyia longipalpis was predominant in the caatinga, and following it came the species L. capixaba and L. oswaldoi. In the tropical rain forest other species were found, such as L. intermedia, L. migonei, L. whitmani, L. yuilli, L.fischeri, L. damascenoi, L. evandroi, L. monticola, and L. lenti. It was found that the geographical limits of the vector species of visceral and cutaneous leishmaniasis are clearly defined by the biological and phytogeographic characteristics.

Trace element differentiation in ferruginous accumulation soil patterns under tropical rainforest of southern Cameroon, the role of climatic change

Regions under tropical rainforest cover, such as central Africa and Brazil are characterised by degradation and dismantling of old ferricrete structures. In southern Cameroon, these processes are relayed by present-day ferruginous accumulation soil facies, situated on the middle and the lower part of hill slopes. These facies become progressively harder towards the surface, containing from bottom to top, mainly kaolinite, kaolinite-goethite and Al-rich goethite-hematite, and are discontinuous to the relictic hematite-dominated ferricrete that exist in the upper part of the hill slope. These features were investigated in terms of geochemical differentiation of trace elements. It appears that, in contrast to the old ferricrete facies, the current ferruginous accumulations are enriched in transitional trace elements (V, Cr, Co, Y, Sc) and Ph, while alkali-earth elements are less differentiated. This recent chemical accumulation is controlled both by intense weathering of the granodiorite bedrock and by mobilisation of elements previously accumulated in the old ferricrete. The observed processes are clearly linked to the present-day humid climate with rising groundwater tables. They slowly replace the old ferricretes formed during Cretaceous time under more seasonal climatic conditions, representing an instructive case of continuos global change. (C) 2002 Elsevier Science B.V. All rights reserved.

Standardization of in-house polymerase chain reaction for the identification of Mycobacterium tuberculosis at the reference tropical disease hospital in the State of Goiás, Brazil

This study compares smear, growth in Lowenstein-Jensen medium, and in-house polymerase chain reaction (PCR) techniques for the detection of Mycobacterium tuberculosis. A total of 72 specimens from 72 patients with clinical symptoms of tuberculosis, including 70 sputum and two bronchial aspirate samples, were tested in parallel by smear, culture, and in-house PCR techniques. From these, 48 (66.6%) were negative by the 3 methods, 2 (2.8%) were smear positive and negative by culture and in-house PCR, 11 (15.3%) were both smear and culture negative, and in-house PCR positive, 7 (9.7%) were positive by the 3 methods, 2 (2.8%) were positive by smear and culture, and negative by PCR, 2 (2.8%) were positive by culture and PCR, but smear negative. After the resolution of discrepancies in PCR results, the sensitivity and specificity for in-house PCR technique to M. tuberculosis relative to the culture, were 81.8% and 81.9%, respectively. These results confirm that this method, in-house PCR, may be a sensitive and specific technique for M. tuberculosis detection, occurring in both positive and negative smear and negative cultures.

Isolation and characterization of the full-length cDNA encoding a member of a novel cytochrome p450 family (CYP320A1) from the tropical freshwater snail, Biomphalaria glabrata, intermediate host for Schistosoma mansoni

Cytochrome p450s (cyp450s) are a family of structurally related proteins, with diverse functions, including steroid synthesis and breakdown of toxins. This paper reports the full-length sequence of a novel cyp450 gene, the first to be isolated from the tropical freshwater snail Biomphalaria glabrata, an important intermediate host of Schistosoma mansoni. The nucleotide sequence is 2291 bp with a predicted amino acid sequence of 584aa. The sequence demonstrates conserved cyp450 structural motifs, but is sufficiently different from previously reported cyp450 sequences to be given a new classification, CYP320A1. Initially identified as down-regulated in partially resistant snails in response to S. mansoni infection, amplification of this gene using RT-PCR in both totally resistant or susceptible snail lines when exposed to infection, and all tissues examined, suggests ubiquitous expression. Characterization of the first cyp450 from B. glabrata is significant in understanding the evolution of these metabolically important proteins.

The feature of papers and citation analysis of eleven journals in tropical medicine indexed by Science Citation Index Expanded

To determine the features of papers, authors, and citation of eleven journals in tropical medicine indexed by Science Citation Index Expanded, the database of the Institute for Scientific Information, we analyzed original articles, editorials, reviews, corrections, letters, biographies, and news published in these journals. The results show that these journals covered 107 countries or regions on six continents. The average number of reference was 23.05, with 87.89% of the references from periodicals. The Price Index was 31.43% and the self-citing rate was 7.02%. The references in the first 20 journals ranked by the amount of citation accounted for 36.71% of the total citations. Brazil, United States, India, and England are more advanced in tropical medicine research. The conclusion is that these journals covered most research done in these countries or regions. Most researches were done by cooperation of the researchers, but many of the publications used outdated articles and should include newer information.

Lack of tax diversity for tropical spastic paraparesis/human T-cell lymphotropic virus type 1 (HTLV-I) associated myelopathy development in HTLV-I-infected subjects in São Paulo, Brazil

The product of human T-cell lymphotropic virus type 1 (HTLV-1) tax gene has a transactivating effect of the viral and cellular gene expression. Genetic variations in this gene have been correlated with differences in clinical outcomes. Based upon its diversity, two closely related substrains, namely tax A and tax B, have been described. The tax A substrain has been found at a higher frequency among human T-cell leukemia virus type 1 (TSP/HAM) patients than among healthy HTLV-I-infected asymptomatic subjects in Japan. In this study, we determined the distribution of tax substrains in HTLV-I-infected subjects in the city of São Paulo, Brazil. Using the ACCII restriction enzyme site, we detected only tax A substrain from 48 TSP/HAM patients and 28 healthy HTLV-I carriers. The sequenced tax genes from nine TSP/HAM patients and five asymptomatic HTLV-I carriers showed a similar pattern of mutation, which characterizes tax A. Our results indicate that HTLV-I tax subtypes have no significant influences on TSP/HAM disease progression. Furthermore, monophyletic introduction of HTLV-I to Brazil probably occurred during the African slave trade many years ago.

Molecular and morphological characterization of heterorhabditid entomopathogenic nematodes from the tropical rainforest in Brazil

Despite massive losses of primary forest, the Amazonian rainforest remains an extremely rich source of biodiversity. In recent years, entomopathogenic nematodes (EPNs) have been isolated from soil in various parts of the world and used successfully as biological control agents against numerous insect pests. Therefore, a sampling in the rainforest of Monte Negro, Rondônia, Brazil was conducted with the aim of discovering new strains and/or species of EPNs for future development as biological control agents. From 156 soil samples taken at nine collecting sites, 19 isolates were obtained, all of them belonging to the genus Heterorhabditis. Four strains were subjected to detailed morphological and molecular evaluation. Based on morphometrics and internal transcribed spacer (ITS) sequence data, the strains LPP1, LPP2 and LPP4 were identified as Heterorhabditis indica, whereas LPP7 was considered Heterorhabditis baujardi. Comparative analysis of the ITS1 sequence of H. indica and H. baujardi isolates showed a polymorphic site for the restriction enzyme Tth 111 that could be used to distinguish the two species. Consequently, strains LPP1, LPP2, LPP3, LPP4, and LPP9 were identified as H. indica, whereas LPP5, LPP7, LPP8 and LPP10 were identified as H. baujardi.

The Quest for the Oracle Birds: Researching the Chinese Community in Colonial Mexico (1565-1700)

The Asian Diaspora in the Americas in the 16th and 17th has been neglected by scholars for a long time. This fact is baffling, not only for the great interest of this topic in of itself, but also because it could provide new knowledge of colonial Mexico, especially in terms of the interaction among the many groups that populated the colony. This early movement of people and ideas across the largest extension of water in the planet is characteristic of what has been called the ¿archaic globalization,¿ and thus research on these matters could contribute to the history of globalization.In this presentation, I seek to further elaborate on the themes outlined by Edward Slack in The Chinos in New Spain: A Corrective Lens for a Distorted Image, an article published in 2009 in the Journal of World History. Firstly, I would like to bring forth some evidence that indicates that Asian religious practices were present in Mexico in the 1600s. Furthermore, I will argue that the traces of these practices are still visible today, in the form of a popular fortune-telling tradition. Secondly, I intend to provide some information about the arrival, settlement and distribution of the Asian Diaspora. I will focus on their distribution within Mexico City. Thirdly, I will elaborate on their occupations, social status and daily life, as well as in the patterns in marriages and relations with other groups. And lastly, I will show how the guild of barbers served as an Asian immigrant reception network.