Altered reactivity of gastric fundus smooth muscle in the mouse with targeted disruption of the kinin B(1) receptor gene

Relaxing action of sodium nitroprusside (SNP) was significantly reduced in the stomach fundus of mice lacking the kinin B(1) receptor (B(1)(-/-)). Increased basal cGMP accumulation was correlated with attenuated SNP induced dose-dependent relaxation in B(1)(-/-) when compared with wild type (WT) control mice. These responses to SNP were completely blocked by the guanylate cyclase inhibitor ODQ(10 mu M). It was also found that Ca(2+)-dependent, constitutive nitric oxide synthase (cNOS) activity was unchanged but the Ca(2+)-independent inducible NOS (iNOS) activity was greater in B(1)(-/-) mice than in WT animals. Zaprinast (100 mu M), a specific phosphodiesterase inhibitor, increased the nitrergic relaxations and the accumulation of the basal as well as the SNP-stimulated cGMP in WT but not in B(1)(-/-) stomach fundus. From these findings it is concluded that the inhibited phosphodiesterase activity and high level of cGMP reduced the resting muscle tone, impairing the relaxant responses of the stomach in B(1)(-/-) mice. In addition, it can be suggested that functional B(2) receptor might be involved in the NO compensatory mechanism associated with the deficiency of kinin B(1) receptor in the gastric tissue of the transgenic mice. (C) 2009 Elsevier Inc. All rights reserved.

Neurodegeneration and Increased Production of Nitrotyrosine, Nitric Oxide Synthase, IFN-gamma and S100 beta Protein in the Spinal Cord of IL-12p40-Deficient Mice Infected with Trypanosoma cruzi

Background/Aim: Chagas` disease is caused by Trypanosoma cruzi and occurs in most Latin American countries. The protozoan may colonize the central nervous system (CNS) of immune-compromised human hosts, thus causing neuronal disorders. Systemic control of the intracellular forms of the parasite greatly depends on the establishment of a TH1 response and subsequent nitric oxide (NO) release. At the CNS, it is known that low concentrations of NO promote neuronal survival and growth, while high concentrations exert toxic effects and neuron death. Accounting for NO production by astrocytes is the glia-derived factor S100 beta, which is overproduced in some neurodegenerative diseases. In the current work, we studied the expression of NO, interferon (IFN)-gamma and S100 beta in the spinal cord tissue of IL-12p40KO mice infected with T. cruzi, a model of neurodegenerative process. Methods: IL-12p40KO and wild-type (WT) female mice infected with T. cruzi Sylvio X10/4 (10(5) trypomastigotes, intraperitoneally) were euthanized when IL-12p40KO individuals presented limb paralysis. Spinal cord sections were submitted to immunohistochemical procedures for localization of neurofilament, laminin, nitrotyrosine, NO synthases (NOS), IFN-gamma and S100 beta. The total number of neurons was estimated by stereological analysis and the area and intensity of immunoreactivities were assessed by microdensitometric/morphometric image analysis. Results: No lesion was found in the spinal cord sections of WT mice, while morphological disarrangements, many inflammatory foci, enlarged vessels, amastigote nests and dying neurons were seen at various levels of IL-12p40KO spinal cord. Compared to WT mice, IL-12p40KO mice presented a decrement on total number of neurons (46.4%, p<0.05) and showed increased values of immunoreactive area for nitrotyrosine (239%, p<0.01) and NOS (544%, p<0.001). Moreover, the intensity of nitrotyrosine (16%, p<0.01), NOS (38%, p<0.05) and S100 beta (21%, p<0.001) immunoreactivities were also augmented. No IFN-gamma labeled cells were seen in WT spinal cord tissue, contrary to IL-12p40KO tissue that displayed inflammatory infiltrating cells and also some parenchymal cells positively labeled.Conclusion: We suggest that overproduction of NO may account for neuronal death at the spinal cord of T. cruzi-infected IL-12p40KO mice and that IFN-gamma and S100 beta may contribute to NOS activation in the absence of IL-12. Copyright (C) 2009 S. Karger AG, Basel

5-Lipoxygenase plays a role in the control of parasite burden and contributes to oxidative damage of erythrocytes in murine Chagas` disease

Chagas` disease is accompanied by severe anemia and oxidative stress, which may contribute to mortality. In this study, we investigated the role of 5-lipoxygenase (5-LO) in the control of parasitism and anemia associated with oxidative damage of erythrocytes in experimental Trypanosoma cruzi infection. Wild-type C57BL/6, 129Sv mice treated or not with nordihydroguaiaretic acid (NDGA, 5-LO inhibitor), mice lacking the 5-LO enzyme gene (5-LO(-/-)) and inducible nitric oxide synthase gene (iNOS(-/-)) were infected with the Y strain of T cruzi. impairment of 5-LO resulted in increased numbers of trypomastigote forms in the blood and amastigote forms in the heart of infected mice. We assessed oxidative stress in erythrocytes by measuring oxygen uptake, induction time and chemiluminescence following treatment with tert-butyl hydroperoxide (TBH). Our results show that 5-LO metabolites increased lipid peroxidation levels in erythrocytes during the early phase of murine T cruzi infection. NDGA treatment reduced oxidative damage of erythrocytes in C57BL/6 T cruzi-infected mice but not in C57BL/6 iNOS-/- infected mice, showing that the action of NDGA is dependent on endogenous nitric oxide (NO). In addition, our results show that 5-LO metabolites do not participate directly in the development of anemia in infected mice. We conclude that 5-LO products may not only play a major role in controlling heart tissue parasitism, i.e., host resistance to acute infection with T cruzi in vivo, but in the event of an infection also play an important part in erythrocyte oxidative stress, an NO-dependent effect. (C) 2009 Elsevier B.V. All rights reserved.

Capillariaisis (Trichurida, Trichinellidae, Capillaria hepatica) in the Brazilian Amazon: low pathogenicity, low infectivity and a novel mode of transmission

Background: Human capillariasis caused by Capillaria hepatica (syn. Calodium hepaticum) is a rare disease with no more than 40 cases registered around the world. Classically, the disease has severe symptoms that mimic acute hepatitis. Natural reservoirs of C. hepatica are urban rodents (Mus musculus and Rattus novergicus) that harbor their eggs in the liver. After examining the feces of 6 riverine inhabitants (Rio Preto area, 8 degrees 03`S and 62 degrees 53`W to 8 degrees 14`S and 62 degrees 52`W) of the State of Rondonia, Brazil, and identifying C. hepatica eggs in their feces, the authors decided to investigate the real dimension of these findings by looking for two positive signals. Methods: Between June 1(st) and 15(th), 2008, 246 out of 304 individuals were clinically examined. Blood samples were collected, kept under -20 degrees C, and test by the indirect immunofluorescence technique. Results: The first positive signal was the presence of specific antibodies at 1: 150 dilution, which indicates that the person is likely to have been exposed to eggs, most likely non-infective eggs, passing through the food chain or via contaminated food (total prevalence of 34.1%). A second more specific signal was the presence of antibodies at higher titers, thus indicating true infection. Conclusions: The authors concluded that only two subjects were really infected (prevalence of 0.81%); the rest was false-positives that were sensitized after consuming non-embryonated eggs. The present study is the first one carried out in a native Amazonian population and indicates the presence of antibodies against C. hepatica in this population. The results further suggest that the transmission of the parasite occurs by the ingestion of embryonated eggs from human feces and/or carcasses of wild animals. The authors propose a novel mode of transmission, describing the disease as a low pathogenic one, and showing low infectivity.

Species diversity of Leishmania (Viannia) parasites circulating in an endemic area for cutaneous leishmaniasis located in the Atlantic rainforest region of northeastern Brazil

OBJECTIVES To identify the aetiological agents of cutaneous leishmaniasis and to investigate the genetic polymorphism of Leishmania (Viannia) parasites circulating in an area with endemic cutaneous leishmaniasis (CL) in the Atlantic rainforest region of northeastern Brazil. METHODS Leishmania spp. isolates came from three sources: (i) patients diagnosed clinically and parasitologically with CL based on primary lesions, secondary lesions, clinical recidiva, mucocutaneous leishmaniasis and scars; (ii) sentinel hamsters, sylvatic or synanthropic small rodents; and (iii) the sand fly species Lutzomyia whitmani. Isolates were characterised using monoclonal antibodies, multilocus enzyme electrophoresis (MLEE) and polymerase chain reaction-restriction fragment length polymorphism of the internal transcribed spacer region rDNA locus. RESULTS Seventy-seven isolates were obtained and characterised. All isolates were identified as Leishmania (Viannia) braziliensis serodeme 1 based on reactivity to monoclonal antibodies. MLEE identified 10 zymodemes circulating in the study region. Most isolates were classified as zymodemes closely related to L. (V.) braziliensis, but five isolates were classified as Leishmania (Viannia) shawi. All but three of the identified zymodemes have so far been observed only in the study region. Enzootic transmission and multiclonal infection were observed. CONCLUSIONS Our results confirm that transmission cycle complexity and the co-existence of two or more species in the same area can affect the level of genetic polymorphism in a natural Leishmania population. Although it is not possible to make inferences as to the modes of genetic exchange, one can speculate that some of the zymodemes specific to the region are hybrids of L. (V.) braziliensis and L. (V.) shawi.

Singlet oxygen generation in the reaction centers of Rhodobacter sphaeroides

Singlet oxygen ((1)O(2)) generation in the reaction centers (RCs) of Rhodobacter sphaeroides wild type was characterized by luminescent emission in the near infrared region (time resolved transients and emission spectra) and quantified to have quantum yield of 0.03 +/- 0.005. (1)O(2) emission was measured as a function of temperature, ascorbate, urea and potassium ferricyanide concentrations and as a function of incubation time in H(2)O: D(2)O mixtures. (1)O(2) was shown to be affected by the RC dynamics and to originate from the reaction of molecular oxygen with two sources of triplets: photoactive dimer formed by singlet-triplet mixing and bacteriopheophytin formed by direct photoexcitation and intersystem crossing.

Role of sigma(54) in the regulation of genes involved in type I and type IV pili biogenesis in Xylella fastidiosa

The phytopathogen Xylella fastidiosa produces long type IV pili and short type I pili involved in motility and adhesion. In this work, we have investigated the role of sigma factor sigma(54) (RpoN) in the regulation of fimbrial biogenesis in X. fastidiosa. An rpoN null mutant was constructed from the non-pathogenic citrus strain J1a12, and microarray analyses of global gene expression comparing the wild type and rpoN mutant strains showed few genes exhibiting differential expression. In particular, gene pilA1 (XF2542), which encodes the structural pilin protein of type IV pili, showed decreased expression in the rpoN mutant, whereas two-fold higher expression of an operon encoding proteins of type I pili was detected, as confirmed by quantitative RT-PCR (qRT-PCR) analysis. The transcriptional start site of pilA1 was determined by primer extension, downstream of a sigma(54)-dependent promoter. Microarray and qRT-PCR data demonstrated that expression of only one of the five pilA paralogues, pilA1, was significantly reduced in the rpoN mutant. The rpoN mutant made more biofilm than the wild type strain and presented a cell-cell aggregative phenotype. These results indicate that sigma(54) differentially regulates genes involved in type IV and type I fimbrial biogenesis, and is involved in biofilm formation in X. fastidiosa.

Conformational differences between the wild type and V30M mutant transthyretin modulate its binding to genistein: Implications to tetramer stability and ligand-binding

Transthyretin (TTR) is a tetrameric beta-sheet-rich transporter protein directly involved in human amyloid diseases. It was recently found that the isoflavone genistein (GEN) potently inhibits TTR amyloid fibril formation (Green et al., 2005) and is therefore a promising candidate for TTR amyloidosis treatment. Here we used structural and biophysical approaches to characterize genistein binding to the wild type (TTRwt) and to its most frequent amyloidogenic variant, the V30M mutant. In a dose-dependent manner, genistein elicited considerable increases in both mutant and TTRwt stability as demonstrated by high hydrostatic pressure (HHP) and acid-mediated dissociation/denaturation assays. TTR:GEN crystal complexes and isothermal titration calorimetry (ITC) experiments showed that the binding mechanisms of genistein to the TTRwt and to V30M are different and are dependent on apoTTR structure conformations. Furthermore, we could also identify potential allosteric movements caused by genistein binding to the wild type TTR that explains, at least in part, the frequently observed negatively cooperative process between the two sites of TTRwt when binding ligands. These findings show that TTR mutants may present different ligand recognition and therefore are of value in ligand design for inhibiting TTR amyloidosis. (C) 2010 Elsevier Inc. All rights reserved.

Genome-wide association mapping in a wild avian population identifies a link between genetic and phenotypic variation in a life-history trait

Understanding the genetic basis of traits involved in adaptation is a major challenge in evolutionary biology but remains poorly understood. Here, we use genome-wide association mapping using a custom 50 k single nucleotide polymorphism (SNP) array in a natural population of collared flycatchers to examine the genetic basis of clutch size, an important life-history trait in many animal species. We found evidence for an association on chromosome 18 where one SNP significant at the genome-wide level explained 3.9% of the phenotypic variance. We also detected two suggestive quantitative trait loci (QTLs) on chromosomes 9 and 26. Fitness differences among genotypes were generally weak and not significant, although there was some indication of a sex-by-genotype interaction for lifetime reproductive success at the suggestive QTL on chromosome 26. This implies that sexual antagonism may play a role in maintaining genetic variation at this QTL. Our findings provide candidate regions for a classic avian life-history trait that will be useful for future studies examining the molecular and cellular function of, as well as evolutionary mechanisms operating at, these loci.

Beyond the Threshold: Life in the New Russia

Amanda Sprang spent nine months, from September of 1995 to May of 1996, studying at Colby College's program in St. Petersburg, Russia. Through contacts made during previous trips to Russia in middle and high school, Amanda was able to quickly rekindle her old friendships and make new ones with many young Russians from different backgrounds. The following work is a collection of twelve essays about life in the New Russia. The essays are framed by a foreword and an epilogue that help place the entire work in a historical context. Although the theme of each essay emerges from a particular incident, within every story Amanda has addressed numerous topics relating to Russian life in today’s changing society. Her first essay, “Art Klinika," takes place in an avant-garde night club in St. Petersburg, and includes a brief yet impressionable, encounter with three young Russian men. “The Birthday Party” recalls a wild evening at the home of her close friend, showing how the Russians greet special occasions. Both the third and fourth essays take place in Moscow, where Amanda returns to visit old friends. These two essays portray the lives of the new economic elite in comparison with the average citizen, as well as show how young Russians face the new challenges that greet them. "Politics Russian Style" recalls a political rally in St. Petersburg, and attempts to shed light on the wacky political world of an infant democracy. Chapters Six through Ten take place away from the western cities of St. Petersburg and Moscow, as Amanda brings us to the cold, mysterious land of Siberia in the dead of winter. She recounts her five day train ride with a retired, high-powered, Communist party official, her experiences in the provincial city of Irkutsk, and a brief trip to a Buddhist monastery and, later, an excursion to Lake Baikal. Back in St. Petersburg, Chapter Eleven gives a humorous account of a ski trip with several Russian friends. Amanda finishes her work with her final chapter, “The Dacha," which describes a weekend spent at a Russian country home with her friend's family.

A Preliminary Habitat Suitability Analysis for the Restoration of South China Tigers in the Hupingshan Reserve, China

The South China tiger, Panthera tigris amoyensis, once roamed the greater part of southern China. However, expanding human populations and other anthropogenic effects have resulted in the extinction of the wild population. The Chinese government has expressed interest in a reintroduction program for this species of tigers. Recent studies suggest that the Hupingshan preserve is potentially a good candidate for a tiger reintroduction program. Hupingshan is located on the border of the Hunan and Hubei provinces in Southern China. This study was a preliminary habitat suitability analysis, for the restoration of South China tigers in the Hupingshan reserve, China. ArcGIS 9.0 was used to develop a model that combined roads, railroads, slope, land cover, park classification, and population density. The tiger habitat suitability analysis was performed by weighting and combining the various layers. Preliminary results suggest that the Hupingshan reserve is suitable habitat for the reintroduction of South China tigers.

Reproductive indices in natural nests of giant Amazon river turtles Podocnemis expansa (Schweigger, 1812) (Testudines, Podocnemididae) in the Environmental Protection Area Meanders of the Araguaia river

Realizou-se a contagem dos ovos não eclodidos, dos filhotes vivos e mortos de Podocnemis expansa oriundos de 327 ninhos naturais, localizados nas praias da Área de Proteção Ambiental (APA) - Meandros do Rio Araguaia, onde se determinou a porcentagem de eclosão dos ovos (94,63%); não eclosão (5,37%); sobrevivência (94,24%) e mortalidade dos filhotes (5,76%), e a média de filhotes mortos durante os 15 dias no berçário (0,97%). A média do total de filhotes por ninho foi determinada pela soma do número de filhotes vivos e mortos divididos pelo total de ninhos, enquanto que a média do total de ovos por ninho foi determinada pela soma do número de filhotes vivos, mortos e ovos não eclodidos divididos pelo total de ninhos. Com isso, obtiveram-se os valores médios do número de filhotes vivos (88,98 ± 23,94); mortos (0,37 ± 0,93); ovos não eclodidos (5,07 ± 9,57), e total de ovos (94,42 ± 21,30). A eficiência reprodutiva da população selvagem de P. expansa pode ser afetada por muitos fatores ambientais, como temperatura, umidade e precipitação. Além disso, fatores influenciados pelo homem, como a presença de produtos químicos na água e a possibilidade de doenças infecciosas, também têm impacto significativo. Os dados dos índices reprodutivos obtidos neste estudo são indispensáveis para futuras investigações de anomalias de incubação.

Chlamydophila psittaci in free-living Blue-fronted Amazon parrots (Amazona aestiva) and Hyacinth macaws (Anodorhynchus hyacinthinus) in the Pantanal of Mato Grosso do Sul, Brazil

Chlamydophila psittaci (C. psittaci) infection was evaluated in 77 free-living nestlings of Blue-fronted Amazon parrots (Amazona aestiva) and Hyacinth macaws (Anodorhynchus hyacinthinus) in the Pantanal of Mato Grosso do Sul, Brazil. Tracheal and cloacal swab samples from 32 wild parrot and 45 macaw nestlings were submitted to semi-nested PCR, while serum samples were submitted to complement fixation test (CFT). Although all 32 Amazon parrot serum samples were negative by CFT, cloacal swabs from two birds were positive for Chlamydophila DNA by semi-nested PCR (6.3%); these positive birds were 32 and 45 days old. In macaws, tracheal and cloacal swabs were positive in 8.9% and 26.7% of the samples, respectively. Complement-fixing antibodies were detected in 4.8% of the macaw nestlings; macaw nestlings with positive findings were between 33 and 88 days old. These results indicate widespread dissemination of this pathogen in the two evaluated psittacine populations. No birds had clinical signs suggestive of chlamydiosis. To the best of our knowledge, this is the first report on C. psittaci in free-living Blue-fronted Amazon parrots and Hyacinth macaws in Brazil. (c) 2006 Elsevier B.V. All rights reserved.

Molecular and serological detection of Leishmania spp. in captive wild animals from Ilha Solteira, SP, Brazil

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PREVALENCE of SALMONELLA SPP. ANTIBODIES TO TOXOPLASMA GONDII, and NEWCASTLE DISEASE VIRUS IN FERAL PIGEONS (COLUMBA LIVIA) IN THE CITY of JABOTICABAL, BRAZIL

The rock pigeon (Columba livia) may serve as a reservoir for several pathogenic agents that can be transmitted to poultry, wildlife, domesticated pets, and/or humans via excreta, secretions, or dust from feathers. In addition, ingestion of infected pigeons by wild and domestic animals can also transmit these pathogenic agents. The health status of 126 free-living pigeons in an urban area was evaluated by microbiologic culture for Salmonella and serologic testing for the presence of antibodies for Toxoplasma gondii and for Newcastle disease virus (NDV) from 120 and 109 pigeons, respectively. After drawing blood, the birds were euthanized, and fragments of the liver, spleen, lungs, and gonads, and feces were cultured for Salmonella spp. Salmonella spp. was isolated from 10 birds (7.94%), of which 8 were Salmonella typhimurium, one was Salmonella enterica subsp. enterica serotype 4,12 and one was Salmonella enterica subsp. enterica serotype 4,12,i. Six of 109 pigeons (5.50%) were positive for NDV antibodies when using the hemagglutination inhibition test. Toxoplasma gondii antibodies were detected by immunofluorescence in one of 120 sera tested (0.83%). The results indicate that feral rock pigeons were exposed to NDV and T gondii, although the exposure was low. In addition, these birds had Salmonella spp. and could disseminate this pathogen in the environment.