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.     

Chromosomal distribution of major rDNA and genome size variation in Belostoma angustum Lauck,B. nessimiani Ribeiro & Alecrim,and B. sanctulum Montandon (Insecta,Heteroptera, Belostomatidae)

Genetica - Known as "electric-light bugs", belostomatids potentially act as agents of biological control. The Belostoma genus has holokinetic chromosomes, interspecific variation in...     

Hybridization and polyploidization effects on LTR-retrotransposon activation in potato genome

Hybridization and polyploidization are major forces in plant evolution and potatoes are not an exception. It is proposed that the proliferation of Long Terminal Repeat-retrotransposons (LTR-RT) is related to genome reorganization caused by hybridization and/or polyploidization. The main purpose of the present work was to evaluate the effect of interspecific hybridization and polyploidization on the activation of LTR-RT. We evaluated the proliferation of putative active LTR-RT in a diploid hybrid between the cultivated potato Solanum tuberosum and the wild diploid potato species S. kurtzianum, allotetraploid lines derived from this interspecific hybrid and S. kurtzianum autotetraploid lines (ktz-autotetraploid) using the S-SAP (sequence-specific amplified polymorphism) technique and normalized copy number determination by qPCR. Twenty-nine LTR-RT copies were activated in the hybrid and present in the allotetraploid lines. Major LTR-RT activity was detected in Copia-27, Copia-12, Copia-14 and, Gypsy-22. According to our results, LTR-RT copies were activated principally in the hybrid, there was no activation in allotetraploid lines and only one copy was activated in the autotetraploid.

     

Effects of Ethanolic Extract of Cynara cardunculus (Artichoke) Leaves on Neuroinflammatory and Neurochemical Parameters in a Diet-Induced Mice Obesity Model

Neurochemical Research - This study aimed to evaluate the effect of Cynara cardunculus leaf ethanol extract on inflammatory and oxidative stress parameters in the hypothalamus, prefrontal cortex,...     

Reproductive biology of the lane snapper,Lutjanus synagris (Linnaeus 1758) (Perciformes,Lutjanidae), in the Maranhão continental shelf,Northeast of Brazil

Environmental Biology of Fishes - To clarify the reproductive activity of lane snapper, Lutjanus synagris, a total of 359 specimens of lane snapper were collected in partnership with an artisanal...     

Variation in behavioral responses of the South American sea lion to tourism disturbance: Implications for tourism management

Due to the highly predictable patterns of occupancy on land, pinnipeds are one of the main marine resources observed by tourists, which, in turn, could strongly perturb their behavior. We analyzed the behavioral responses of the South American sea lion (Otaria byronia) to the presence of tourists and its variation according to temporal (2012 vs. 2013 austral summer months), spatial (breeding vs. nonbreeding sites of the colony), and age/sex class (adult males vs. subadult males vs. females) factors, and determined the relationship between the degree of responses by sea lions and the distance of the vessel to the colony, visitation time, and tourist behavior. We recorded 1,232 boat visits during 2012 and 2013. Subadult males were the age/sex class most affected in the breeding site, followed by adult females at the nonbreeding site. More disturbing conduct by tourists, longer visitation time, and vessels closer to the colony caused greater responses by sea lions. The established minimum distance from the colony is not enforced, generating an adverse response by sea lions. We recommend the development of management plans with the local coastal communities to decrease the impact of ecotourism on the species and enhance the sustainability of this industry.