Genomic sequencing of a frog virus 3 strain from cultured American bullfrogs (Lithobates catesbeianus) in Brazil.

Frog virus 3 (FV3) was detected in cultured bullfrogs in Southeast Brazil. Phylodynamic analysis revealed recombination events in this strain that were nearly identical to those detected in North American and Brazilian FV3 strains. These data suggest that international trade of live bullfrogs has spread recombinant strains of FV3.

Direct evidence of singlet molecular oxygen generation from peroxynitrate, a decomposition product of peroxynitrite.

The decomposition of peroxynitrite to nitrite and dioxygen at neutral pH follows complex kinetics, compared to its isomerization to nitrate at low pH. Decomposition may involve radicals or proceed by way of the classical peracid decomposition mechanism. Peroxynitrite (ONOOH/ONOO(-)) decomposition has been proposed to involve formation of peroxynitrate (O(2)NOOH/O(2)NOO(-)) at neutral pH (D. Gupta, B. Harish, R. Kissner and W. H. Koppenol, Dalton Trans., 2009, DOI: 10.1039/b905535e, see accompanying paper in this issue). Peroxynitrate is unstable and decomposes to nitrite and dioxygen. This study aimed to investigate whether O(2)NOO(-) formed upon ONOOH/ONOO(-) decomposition generates singlet molecular oxygen [O(2) ((1)Delta(g))]. As unequivocally revealed by the measurement of monomol light emission in the near infrared region at 1270 nm and by chemical trapping experiments, the decomposition of ONOO(-) or O(2)NOOH at neutral to alkaline pH generates O(2) ((1)Delta(g)) at a yield of ca. 1% and 2-10%, respectively. Characteristic light emission, corresponding to O(2) ((1)Delta(g)) monomolecular decay was observed for ONOO(-) and for O(2)NOOH prepared by reaction of H(2)O(2) with NO(2)BF(4) and of H(2)O(2) with NO(2)(-) in HClO(4). The generation of O(2) ((1)Delta(g)) from ONOO(-) increased in a concentration-dependent manner in the range of 0.1-2.5 mM and was dependent on pH, giving a sigmoid profile with an apparent pK(a) around pD 8.1 (pH 7.7). Taken together, our results clearly identify the generation of O(2) ((1)Delta(g)) from peroxynitrate [O(2)NOO(-) --> NO(2)(-) + O(2) ((1)Delta(g))] generated from peroxynitrite and also from the reactions of H(2)O(2) with either NO(2)BF(4) or NO(2)(-) in acidic media.

Biological hydroperoxides and singlet molecular oxygen generation.

The decomposition of lipid hydroperoxides (LOOH) into peroxyl radicals is a potential source of singlet molecular oxygen ((1)O(2)) in biological systems. Recently, we have clearly demonstrated the generation of (1)O(2) in the reaction of lipid hydroperoxides with biologically important oxidants such as metal ions, peroxynitrite and hypochlorous acid. The approach used to unequivocally demonstrate the generation of (1)O(2) in these reactions was the use of an isotopic labeled hydroperoxide, the (18)O-labeled linoleic acid hydroperoxide, the detection of labeled compounds by HPLC coupled to tandem mass spectrometry (HPLC-MS/MS) and the direct spectroscopic detection and characterization of (1)O(2) light emission. Using this approach we have observed the formation of (18)O-labeled (1)O(2) by chemical trapping of (1)O(2) with anthracene derivatives and detection of the corresponding labeled endoperoxide by HPLC-MS/MS. The generation of (1)O(2) was also demonstrated by direct spectral characterization of (1)O(2) monomol light emission in the near-infrared region (lambda = 1270 nm). In summary, our studies demonstrated that LOOH can originate (1)O(2). The experimental evidences indicate that (1)O(2) is generated at a yield close to 10% by the Russell mechanism, where a linear tetraoxide intermediate is formed in the combination of two peroxyl radicals. In addition to LOOH, other biological hydroperoxides, including hydroperoxides formed in proteins and nucleic acids, may also participate in reactions leading to the generation (1)O(2). This hypothesis is currently being investigated in our laboratory.

Description of novel microsatellite loci in the Neotropical fish Prochilodus argenteus and cross-amplification in P. costatus and P. lineatus

Prochilodus is one of the most important fish resources of South America, in addition to the important role it plays in nutrient cycling of Neotropical rivers. In the present study, we describe the isolation and characterization of nine novel microsatellite loci in Prochilodus argenteus. The number of alleles per polymorphic locus varied from 5 (Par76) to 21 (Par85), revealing a total of 116 alleles. The values of observed and expected heterozygosities ranged from 0.629 (Par69) to 0.926 (Par85 and Par86) and from 0.643 (Par66) to 0.931 (Par80), respectively. Furthermore, the ability of these and other previously described microsatellite markers to amplify orthologous loci was tested in two related species, Prochilodus costatus and Prochilodus lineatus. These loci will be useful for studies of population genetic structure in this group of fishes, and in aiding future genetic mapping studies of P. argenteus.