Occurrence of Aedes (Stegomyia) albopictus (Skuse) in urban area of Tocantins state, Brazil

This is the first report of the presence of Aedes albopictus (Skuse) in the Tocantins State, Brazil, in urban area of the Mateiros city. Immature specimens (aquatic stages) of this vector were collected in water reservoirs, treeholes, old tires and others. The existence of Ae. albopictus in the metropolitan area poses a potential risk for the interaction of this mosquito species with the urban human population.     

Oxidative responses of human and murine macrophages during phagocytosis of Leishmania chagasi.

Leishmania chagasi, the cause of South American visceral leishmaniasis, must survive antimicrobial responses of host macrophages to establish infection. Macrophage oxidative responses have been shown to diminish in the presence of intracellular leishmania. However, using electron spin resonance we demonstrated that murine and human macrophages produce O2-during phagocytosis of opsonized promastigotes. Addition of the O2- scavenger 4-hydroxy-2,2,6,6-tetramethylpiperidine-N-oxyl to cultures resulted in increased infection, suggesting that O2- enhances macrophage leishmanicidal activity. The importance of NO. produced by inducible NO synthase (iNOS) in controlling murine leishmaniasis is established, but its role in human macrophages has been debated. We detected NO. in supernatants from murine, but not human, macrophages infected with L. chagasi. Nonetheless, the iNOS inhibitor N(G)-monomethyl-L-arginine inhibited IFN-gamma-mediated intracellular killing by both murine and human macrophages. According to RNase protection assay and immunohistochemistry, iNOS mRNA and protein were expressed at higher levels in bone marrow of patients with visceral leishmaniasis than in controls. The iNOS protein also increased upon infection of human macrophages with L. chagasi promastigotes in vitro in the presence of IFN-gamma. These data suggest that O2- and NO. each contribute to intracellular killing of L. chagasi in human and murine macrophages.     

Characterization of photodamage to escherichia coli in optical traps

Optical tweezers (infrared laser-based optical traps) have emerged as a powerful tool in molecular and cell biology. However, their usefulness has been limited, particularly in vivo, by the potential for damage to specimens resulting from the trapping laser. Relatively little is known about the origin of this phenomenon. Here we employed a wavelength-tunable optical trap in which the microscope objective transmission was fully characterized throughout the near infrared, in conjunction with a sensitive, rotating bacterial cell assay. Single cells of Escherichia coli were tethered to a glass coverslip by means of a single flagellum: such cells rotate at rates proportional to their transmembrane proton potential (. J. Mol. Biol. 138:541-561). Monitoring the rotation rates of cells subjected to laser illumination permits a rapid and quantitative measure of their metabolic state. Employing this assay, we characterized photodamage throughout the near-infrared region favored for optical trapping (790-1064 nm). The action spectrum for photodamage exhibits minima at 830 and 970 nm, and maxima at 870 and 930 nm. Damage was reduced to background levels under anaerobic conditions, implicating oxygen in the photodamage pathway. The intensity dependence for photodamage was linear, supporting a single-photon process. These findings may help guide the selection of lasers and experimental protocols best suited for optical trapping work.     

Striped catfish (Pangasianodon hypophthalmus) could be suitable for coastal aquaculture

Salinity intrusion in the coastal freshwater rivers due to climate change and construction of the dam in the upstream rivers are alarming in aquaculture. Hence, an experiment was conducted to know the effects of salinity on growth performance, hemato‐biochemical parameters and erythrocytes structure in a commercially cultivable catfish species, striped catfish (Pangasianodon hypophthalmus). Firstly, median lethal concentration (LC₅₀) of salinity for striped catfish was determined and then the fish were exposed to three salinity conditions (4, 8 and 12‰) and a control (0‰). Fish were sacrificed at day 7, 14, 28 and 56 after the start of salinity exposure. The 96 hr LC₅₀ value was found to be 14.87‰. Salinity levels from freshwater to 8‰ showed optimal conditions with high survival rate and good growth performances of fish in terms of weight gain and specific growth rate (SGR). Interestingly, the lowest food conversion ratio (FCR) was found in 4‰ group. The hemoglobin (Hb) level and number of red blood cells (RBCs) were found to be decreased significantly in 8 and 12‰ compared to 0 and 4‰ at the initial days of exposure, while number of white blood cells (WBCs) and glucose level showed opposite scenario. Frequencies of ENA (erythrocytic nuclear abnormalities) and ECA (erythrocytic cellular abnormalities) were significantly increased with increasing salinities in the initial days of exposure. Overall, findings of the present study revealed that striped catfish might be suitable fish species for culture in the brackish water containing salinity up to 10‰.     

Molecular Detection of Leishmania in Phlebotomine Sand Flies (Diptera: Psychodidae) from a Cutaneous Leishmaniasis Focus at Xakriabá Indigenous Reserve,Brazil

Autochthonous cases of American cutaneous leishmaniasis (ACL) have been reported since 2001 in the Xakriabá Indigenous Reserve located in the municipality of São João das Missões in northern Minas Gerais state, Brazil. In order to study the presence of Leishmania DNA in phlebotomine sand flies, six entomological collections were carried out from July 2008 through July 2009, using 40 light traps placed in peridomicile areas of 20 randomly selected houses. From October 2011 through August 2012, another six collections were carried out with 20 light traps distributed among four trails (five traps per trail) selected for a previous study of wild and synanthropic hosts of Leishmania. A total of 4,760 phlebotomine specimens were collected belonging to ten genera and twenty-three species. Single female specimens or pools with up to ten specimens of the same locality, species and date, for Leishmania detection by molecular methods. Species identification of parasites was performed with ITS1 PCR-RFLP using HaeIII enzyme and genetic sequencing for SSU rRNA target. The presence of Leishmania DNA was detected in eleven samples from peridomicile areas: Lu. longipalpis (two), Nyssomyia intermedia (four), Lu. renei (two), Lu. ischnacantha, Micropygomyia goiana and Evandromyia lenti (one pool of each specie). The presence of Leishmania DNA was detected in twelve samples from among the trails: Martinsmyia minasensis (six), Ny. intermedia (three), Mi. peresi (two) and Ev. lenti (one). The presence of Leishmania infantum DNA in Lu. longipalpis and Leishmania braziliensis DNA in Ny. intermediasupport the epidemiological importance of these species of sand flies in the cycle of visceral and cutaneous leishmaniasis, respectively. The results also found other species associated with Leishmania DNA, such as Mt. minasensis and Ev. lenti, which may participate in a wild and/or synanthropic cycle of Leishmania transmission in the studied area.