Enhanced Astrocytic Nitric Oxide Production and Neuronal Modifications in the Neocortex of a NOS2 Mutant Mouse

BACKGROUND: It has been well accepted that glial cells in the central nervous system (CNS) produce nitric oxide (NO) through the induction of a nitric oxide synthase isoform (NOS2) only in response to various insults. Recently we described rapid astroglial, NOS2-dependent, NO production in the neocortex of healthy mice on a time scale relevant to neuronal activity. To explore a possible role for astroglial NOS2 in normal brain function we investigated a NOS2 knockout mouse (B6;129P2-Nos2(tm1Lau)/J, Jackson Laboratory). Previous studies of this mouse strain revealed mainly altered immune responses, but no compensatory pathways and no CNS abnormalities have been reported. METHODOLOGY/PRINCIPAL FINDINGS: To our surprise, using NO imaging in brain slices in combination with biochemical methods we uncovered robust NO production by neocortical astrocytes of the NOS2 mutant. These findings indicate the existence of an alternative pathway that increases basal NOS activity. In addition, the astroglial mutation instigated modifications of neuronal attributes, shown by changes in the membrane properties of pyramidal neurons, and revealed in distinct behavioral abnormalities characterized by an increase in stress-related parameters. CONCLUSIONS/SIGNIFICANCE: The results strongly indicate the involvement of astrocytic-derived NO in modifying the activity of neuronal networks. In addition, the findings corroborate data linking NO signaling with stress-related behavior, and highlight the potential use of this genetic model for studies of stress-susceptibility. Lastly, our results beg re-examination of previous studies that used this mouse strain to examine the pathophysiology of brain insults, assuming lack of astrocytic nitrosative reaction

SEASONAL DISTRIBUTION OF MALARIA VECTORS (DIPTERA: CULICIDAE) IN RURAL LOCALITIES OF PORTO VELHO, RONDÔNIA, BRAZILIAN AMAZON

We conducted a survey of the malaria vectors in an area where a power line had been constructed, between the municipalities of Porto Velho and Rio Branco, in the states of Rondônia and Acre, respectively. The present paper relates to the results of the survey of Anopheles fauna conducted in the state of Rondônia. Mosquito field collections were performed in six villages along the federal highway BR 364 in the municipality of Porto Velho, namely Porto Velho, Jaci Paraná, Mutum Paraná, Vila Abunã, Vista Alegre do Abunã, and Extrema. Mosquito captures were performed at three distinct sites in each locality during the months of February, July, and October 2011 using a protected human-landing catch method; outdoor and indoor captures were conducted simultaneously at each site for six hours. In the six sampled areas, we captured 2,185 mosquitoes belonging to seven Anopheles species. Of these specimens, 95.1% consisted of Anopheles darlingi, 1.8% An. triannulatus l.s., 1.7% An. deaneorum, 0.8% An. konderi l.s., 0.4 An. braziliensis, 0.1% An. albitarsis l.s., and 0.1% An. benarrochi. An. darlingi was the only species found in all localities; the remaining species occurred in sites with specific characteristics

A First Generation Microsatellite- and SNP-Based Linkage Map of Jatropha

Jatropha curcas is a potential plant species for biodiesel production. However, its seed yield is too low for profitable production of biodiesel. To improve the productivity, genetic improvement through breeding is essential. A linkage map is an important component in molecular breeding. We established a first-generation linkage map using a mapping panel containing two backcross populations with 93 progeny. We mapped 506 markers (216 microsatellites and 290 SNPs from ESTs) onto 11 linkage groups. The total length of the map was 1440.9 cM with an average marker space of 2.8 cM. Blasting of 222 Jatropha ESTs containing polymorphic SSR or SNP markers against EST-databases revealed that 91.0%, 86.5% and 79.2% of Jatropha ESTs were homologous to counterparts in castor bean, poplar and Arabidopsis respectively. Mapping 192 orthologous markers to the assembled whole genome sequence of Arabidopsis thaliana identified 38 syntenic blocks and revealed that small linkage blocks were well conserved, but often shuffled. The first generation linkage map and the data of comparative mapping could lay a solid foundation for QTL mapping of agronomic traits, marker-assisted breeding and cloning genes responsible for phenotypic variation

Epidemiologic aspects of the malaria transmission cycle in an area of very low incidence in Brazil

BACKGROUND: Extra-Amazonian autochthonous Plasmodium vivax infections have been reported in mountainous regions surrounded by the Atlantic Forest in Espírito Santo state, Brazil. METHODS: Sixty-five patients and 1,777 residents were surveyed between April 2001 and March 2004. Laboratory methods included thin and thick smears, multiplex-PCR, immunofluorescent assay (IFA) against P. vivax and Plasmodium malariae crude blood-stage antigens and enzyme-linked immunosorbent assay (ELISA) for antibodies against the P. vivax-complex (P. vivax and variants) and P. malariae/Plasmodium brasilianum circumsporozoite-protein (CSP) antigens. RESULTS: Average patient age was 35.1 years. Most (78.5%) were males; 64.6% lived in rural areas; 35.4% were farmers; and 12.3% students. There was no relevant history of travel. Ninety-five per cent of the patients were experiencing their first episode of malaria. Laboratory data from 51 patients were consistent with P. vivax infection, which was determined by thin smear. Of these samples, 48 were assayed by multiplex-PCR. Forty-five were positive for P. vivax, confirming the parasitological results, while P. malariae was detected in one sample and two gave negative results. Fifty percent of the 50 patients tested had IgG antibodies against the P. vivax-complex or P. malariae CSP as determined by ELISA. The percentages of residents with IgM and IgG antibodies detected by IFA for P. malariae, P. vivax and Plasmodium falciparum who did not complain of malaria symptoms at the time blood was collected were 30.1% and 56.5%, 6.2% and 37.7%, and 13.5% and 13%, respectively. The same sera that reacted to P. vivax also reacted to P. malariae. The following numbers of samples were positive in multiplex-PCR: 23 for P. vivax; 15 for P. malariae; 9 for P. falciparum and only one for P. falciparum and P. malariae. All thin and thick smears were negative. ELISA against CSP antigens was positive in 25.4%, 6.3%, 10.7% and 15.1% of the samples tested for "classical" P. vivax (VK210), VK247, P. vivax-like and P. malariae, respectively. Anopheline captures in the transmission area revealed only zoophilic and exophilic species. CONCLUSION: The low incidence of malaria cases, the finding of asymptomatic inhabitants and the geographic separation of patients allied to serological and molecular results raise the possibility of the existence of a simian reservoir in these areas

Gene polymorphisms against DNA damage induced by hydrogen peroxide in leukocytes of healthy humans through comet assay: a quasi-experimental study

<p>Abstract</p> <p>Background</p> <p>Normal cellular metabolism is well established as the source of endogenous reactive oxygen species which account for the background levels of oxidative DNA damage detected in normal tissue. Hydrogen peroxide imposes an oxidative stress condition on cells that can result in DNA damage, leading to mutagenesis and cell death. Several potentially significant genetic variants related to oxidative stress have already been identified, and angiotensin I-converting enzyme (ACE) inhibitors have been reported as possible antioxidant agents that can reduce vascular oxidative stress in cardiovascular events.</p> <p>Methods</p> <p>We investigate the influences of haptoglobin, manganese superoxide dismutase (MnSOD Val9Ala), catalase (CAT -21A/T), glutathione peroxidase 1 (GPx-1 Pro198Leu), ACE (I/D) and gluthatione S-transferases GSTM1 and GSTT1 gene polymorphisms against DNA damage and oxidative stress. These were induced by exposing leukocytes from peripheral blood of healthy humans (N = 135) to hydrogen peroxide (H₂O₂), and the effects were tested by comet assay. Blood samples were submitted to genotyping and comet assay (before and after treatment with H₂O₂at 250 μM and 1 mM).</p> <p>Results</p> <p>After treatment with H₂O₂at 250 μM, the GPx-1 polymorphism significantly influenced results of comet assay and a possible association of the Pro/Leu genotype with higher DNA damage was found. The highest or lowest DNA damage also depended on interaction between GPX-1/ACE and Hp/GSTM1T1 polymorphisms when hydrogen peroxide treatment increased oxidative stress.</p> <p>Conclusions</p> <p>The GPx-1 polymorphism and the interactions between GPX-1/ACE and Hp/GSTM1T1 can be determining factors for DNA oxidation provoked by hydrogen peroxide, and thus for higher susceptibility to or protection against oxidative stress suffered by healthy individuals.</p