Peroxynitrite oxidizes erythrocyte membrane band 3 protein and diminishes its anion transport capacity

We describe an altered membrane band 3 protein-mediated anion transport in erythrocytes exposed to peroxynitrite, and relate the loss of anion transport to cell damage and to band 3 oxidative modifications. We found that peroxynitrite down-regulate anion transport in a dose dependent relation (100–300 μmoles/l). Hemoglobin oxidation was found at all peroxynitrite concentrations studied. A dose-dependent band 3 protein crosslinking and tyrosine nitration were also observed. Band 3 protein modifications were concomitant with a decrease in transport activity. ( ? )-Epicatechin avoids band 3 protein nitration but barely affects its transport capacity, suggesting that both processes are unrelated. N-acetyl cysteine partially reverted the loss of band 3 transport capacity. It is concluded that peroxynitrite promotes a decrease in anion transport that is partially due to the reversible oxidation of band 3 cysteine residues. Additionally, band 3 tyrosine nitration seems not to be relevant for the loss of its anion transport capacity.     

Renoprotection by α-mangostin is related to the attenuation in renal oxidative/nitrosative stress induced by cisplatin nephrotoxicity

Cisplatin (CDDP) is a chemotherapeutic agent that produces nephrotoxicity associated with oxidative/nitrosative stress. α-Mangostin (α-M) is a xanthone extracted from mangosteen with antioxidant and anti-inflammatory properties. The purpose of this study was to evaluate the renoprotective effect of α-M on the CDDP-induced nephrotoxicity. α-M was administered (12.5 mg/kg/day, i.g.) for 10 days (7 days before and 3 days after CDDP injection). On day 7, rats were treated with a single injection of CDDP (7.5 mg/Kg, i.p.); 3 days after the rats were killed. α-M attenuated renal dysfunction, structural damage, oxidative/nitrosative stress, decrease in catalase expression and increase in mRNA levels of tumour necrosis factor alpha and transforming growth factor beta. In conclusion the renoprotective effect of α-M on CDDP-induced nephrotoxicity was associated with the attenuation in oxidative/nitrosative stress and inflammatory and fibrotic markers and preservation of catalase activity.     

Acute Phase Immune Response to Exercise Coexists with Decreased Neutrophil Antioxidant Enzyme Defences

Long-duration or damaging exercise initiates reactions that resemble the acute phase response to infection and induces neutrophil priming for oxidative activity. Our objective was to establish the status of the antioxidant defences and of the oxidative equilibrium in the neutrophils of sportsmen prior to and after intense physical exercise. Nine voluntary male professional cyclists participated in this study. The exercise was a cycling mountain stage (171 km) and the cyclists took a mean &#45 SEM of 270 &#45 12 min to complete it. We determined the activities of catalase (CAT), glutathione reductase (GR), glutathione peroxidase (GPx), the levels and activity of superoxide dismutase (SOD), the concentrations of ascorbate, glutathione and glutathione disulphide (GSSG) and DNA levels in neutrophils. The cycling stage decreased enzyme activities expressed per DNA units: CAT (33%), SOD (38%), GPx (65%); increased ascorbate concentration in neutrophils and decreased the GSH/GSSG ratio and the enzyme activities expressed per DNA units. Neutrophils could contribute to plasma antioxidant defences against oxidative stress induced by exercise because they probably provide antioxidant enzymes and ascorbate.     

Relationship between environmental variables and surface activity of scorpions in the Arid Chaco ecoregion of Argentina

Many environmental factors may influence the activity of scorpions in arid ecosystems. In this study, we examined the effects of such factors on scorpion activity at a mature and a secondary forest site in the Chancaní Reserve (Arid Chaco ecoregion in Córdoba, Argentina). Scorpions were collected using pitfall traps, and their nocturnal activity was observed by means of UV light during 14 nights. Temperature, air humidity, atmospheric pressure, and wind velocity were measured, and the percentage of visible moon was estimated. A total of 440 scorpions, representing seven species belonging to two families (Bothriuridae and Buthidae), were observed in the study area. Brachistosternus ferrugineus was the species most commonly observed using both methods. Mature and secondary forest shared slightly more than 50% of species. Surface activity of scorpions observed with the two methods differed significantly between the two areas. Surface activity of all scorpions and of B. ferrugineus were negatively related to the phase of the moon and positively related to air temperature. Physical factors thus have important effects on scorpion activity.     

SELECTIVE CULTURES FOR THE ISOLATION OF BIOSURFACTANT PRODUCING BACTERIA: COMPARISON OF DIFFERENT COMBINATIONS OF ENVIRONMENTAL INOCULA AND HYDROPHOBIC CARBON SOURCES

The potential of estuarine microniches as reservoirs of biosurfactant-producing bacteria was evaluated by testing different combinations of inocula and hydrophobic carbon sources. Selective cultures using diesel, petroleum, or paraffin as hydrophobic carbon sources were prepared and inoculated with water from the surface microlayer, bulk sediments, and sediment of the rhizosphere of Halimione portulacoides. These inocula were compared regarding the frequency of biosurfactant-producing strains among selected isolates. The community structure of the selective cultures was profiled using denaturing gradient gel electrophoresis (DGGE) of the 16S rRNA gene fragments at the end of the incubation. The DGGE profiles corresponding to the communities established in selective cultures at the end of the incubation revealed that communities were different in terms of structural diversity. The highest diversity was observed in the selective cultures containing paraffin (H ^' = 2.5). Isolates were obtained from the selective cultures (66) and tested for biosurfactant production by the atomized oil assay. Biosurfactant production was detected in 17 isolates identified as Microbacterium, Pseudomonas, Rhodococcus, and Serratia. The combination of estuarine surface microlayer (SML) water as inoculum and diesel as carbon source seems promising for the isolation of surfactant-producing bacteria. Supplemental materials are available for this article. Go to the publisher's online edition of Preparative Biochemistry and Biotechnology to view the supplemental file.     

Resistance to freezing temperatures in Aedes (Ochlerotatus) albifasciatus (Macquart) eggs (Diptera: Culicidae) from two different climatic regions of Argentina

Aedes (Ochlerotatus) albifasciatus (Macquart) has the capacity to proliferate in different kinds of climates within its distribution range in South America. With the aim of studying local thermal adaptations of eggs, we exposed egg stocks from two climatically different localities: temperate humid pampa (Buenos Aires) and cold arid Patagonian (Sarmiento), to freezing conditions and then evaluated the effect on some features at this level. First, we thermally described the substrate where this species lays its eggs in the arid region. A typical thermal condition during winter was 10 h at ?12° C. Second, we evaluated the effect of freezing on primary hatching (vs total hatching) and embryo survival. We also compared the proportion of embryonated eggs from both populations. The proportions of embryonated eggs were not different between localities, with averages of 78% and 83% in Sarmiento and Buenos Aires, respectively. Survival was equally successful after freezing in the two localities with an average range between 94–99%. Whether or not the eggs from Buenos Aires and Sarmiento were under freezing conditions, hatching was more than 98% after the first flooding. The results suggest that eggs of Ae. albifasciatus from Sarmiento and Buenos Aires have the same ability to survive at extreme temperatures (<0° C), showing a regional thermal adaptation rather than a local one.     

Intestinal perfusion indicates high reliance on paracellular nutrient absorption in an insectivorous bat Tadarida brasiliensis

Flying vertebrates have been hypothesized to have a high capacity for paracellular absorption of nutrients. This could be due to high permeability of the intestines to nutrient-sized molecules (i.e., in the size range of amino acids and glucose, MW 75–180 Da). We performed intestinal luminal perfusions of an insectivorous bat, Tadarida brasiliensis. Using radio-labeled molecules, we measured the uptake of two nutrients absorbed by paracellular and transporter-mediated mechanisms (l-proline, MW 115 Da, and d-glucose, MW 180 Da) and two carbohydrates that have no mediated transport (l-arabinose, MW 150 Da, and lactulose, MW 342 Da). Absorption of lactulose (0.61 ± 0.06 nmol min^? 1 cm^? 1) was significantly lower than that of the smaller arabinose (1.09 ± 0.04 nmol min^? 1 cm^? 1). Glucose absorption was significantly lower than that of proline at both nutrient concentrations (10 mM and 75 mM). Using the absorption of arabinose to estimate the portion of proline absorption that is paracellular, we calculated that 25.1 ± 3.0% to 66.2 ± 7.8% of proline absorption is not transporter-mediated (varying proline from 1 mM to 75 mM). These results confirm our predictions that 1) paracellular absorption is molecule size selective, 2) absorption of proline would be greater than glucose absorption in an insectivore, and 3) paracellular absorption represents a large fraction of total nutrient absorption in bats.     

Genital microsporidiosis in women with AIDS: A post-mortem study

BackgroundMicrosporidiosis is a life threatening opportunistic infection of AIDS patients. The infection is usually restricted to specific anatomical areas, but could become systemic depending on the involved species. Genital microsporidiosis in female patients is rare.ObjectiveTo report genital microsporidiosis in female AIDS patients.MethodsTissues samples from the genital tract (ovary, fallopian tubes and uterus) of eight deceased women who died of wasting syndrome associated to AIDS and disseminated microsporidiosis at the Institute of Tropical Medicine Pedro Kourí were collected between 1997 and 2005. Using an indirect immunohistochemistry assay the microsporidia species involved in those cases were identified.ResultsWe report several cases of microsporidial infection of the female genital tract. Six out of eight women with the disseminated form of the disease showed the presence of microsporidia in the genital tract. Encephalitozoon cuniculi and Encephalitozoon hellem were identified in the internal lining epithelium of the fallopian tubes and endometrium.ConclusionsMicrosporidia species could disseminate to other organs and become systemic in severe immunocompromised cases. To our knowledge this is the greatest number of female genital tract microsporidiosis cases so far reported in humans.