Ultrasensitive Simultaneous Quantification of 1,N(2)-Etheno-2 `-deoxyguanosine and 1,N(2-)Propano-2 `-deoxyguanosine in DNA by an Online Liquid Chromatography-Electrospray Tandem Mass Spectrometry Assay

Exocyclic DNA adducts produced by exogenous and endogenous compounds are emerging as potential tools to study a variety of human diseases and air pollution exposure. A highly sensitive method involving online reverse-phase high performance liquid chromatography with electrospray tandem mass spectrometry detection in the multiple reaction monitoring mode and employing stable isotope-labeled internal standards was developed for the simultaneous quantification of 1,N(2)-etheno-2`-deoxyguanosine (1,N(2)-epsilon dGuo) and 1,N(2)-propano-2`-deoxyguanosine (1,N(2)-propanodGuo) in DNA. This methodology permits direct online quantification of 2`-deoxyguanosine and ca. 500 amol of adducts in 100 mu g of hydrolyzed DNA M the same analysis. Using the newly developed technique, accurate determinations of 1,N(2)-etheno-2`-deoxyguanosine and 1,N2-propano-2`-deoxyguanosine levels in DNA extracts of human cultured cells (4.01 +/- 0.32 1,N(2)-epsilon dGuo/10(8) dGuo and 3.43 +/- 0.33 1,N(2)-propanodGuo/10(8) dGuo) and rat tissue (liver, 2.47 +/- 0.61 1,N(2)-epsilon dGuo/10(8) dGuo and 4.61 +/- 0.69 1,N(2)-propanodGuo/108 dGuo; brain, 2.96 +/- 1.43,N(2)-epsilon dGuo/10(8) dGuo and 5.66 +/- 3.70 1,N(2)-propanoclGuo/10(8) dGuo; and lung, 0,87 +/- 0.34 1,N(2)-edGuo/ 10(8) dGuo and 2.25 +/- 1.72 1,N(2)-propanodGuo/10(8) dGuo) were performed. The method described herein can be used to study the biological significance of exocyclic DNA adducts through the quantification of different adducts in humans and experimental an with pathological conditions and after air pollution exposure.

Psammophilous halacarid mites (Trombidiformes, Halacaridae) from the North Coast of Sao Paulo State, Brazil

Five halacarid species are reported from the Brazilian coast for the first time. Scaptognathides delicatulus, formerly known only from its type locality in Kuwait; Scaptognathus gibbosus, known from Galapagos and Somalia; and Scaptognathus insularis known from northeastern Australia, have their distributions extended. Along with these new records, Halacaroides antoniazziae sp. nov. and Acarochelopodia caissara sp. nov. are described. Halacaroides antoniazziae sp. nov. differs from its congeners by the presence of three subgenital setae in males and none in females, 41-44 perigenital setae and two posterior external genital acetabula in males. Acarochelopodia caissara sp. nov. has a rounded anterior epimeral plate margin, the posterior epimeral plates are partially divided into two halves but anteriorly joined by a narrow band, the dorsal setae on tarsus I are grouped 1:2, and the anterior and posterior dorsal plates have a length: width ratio of 1.61-1.77 and 1.60-1.70, respectively.

Chronic resistance training decreases MuRF-1 and Atrogin-1 gene expression but does not modify Akt, GSK-3 beta and p70S6K levels in rats

Long-term adaptation to resistance training is probably due to the cumulative molecular effects of each exercise session. Therefore, we studied in female Wistar rats the molecular effects of a chronic resistance training regimen (3 months) leading to skeletal muscle hypertrophy in the plantaris muscle. Our results demonstrated that muscle proteolytic genes MuRF-1 and Atrogin-1 were significantly decreased in the exercised group measured 24 h after the last resistance exercise session (41.64 and 61.19%, respectively; P < 0.05). Nonetheless, when measured at the same time point, 4EBP-1, GSK-3 beta and eIF2B epsilon mRNA levels and Akt, GSK-3 beta and p70S6K protein levels (regulators of translation initiation) were not modified. Such data suggests that if gene transcription constitutes a control point in the protein synthesis pathway this regulation probably occurs in early adaptation periods or during extreme situations leading to skeletal muscle remodeling. However, proteolytic gene expression is modified even after a prolonged resistance training regimen leading to moderate skeletal muscle hypertrophy.

Interaction of giant extracellular Glossoscolex paulistus hemoglobin (HbGp) with zwitterionic surfactant N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS): Effects of oligomeric dissociation

The present work focuses on the interaction between the zwitterionic surfactant N-hexadecyl-N,N-dimethyl-3-ammonio-1-propanesulfonate (HPS) and the giant extracellular hemoglobin of Glossoscolex paulistus (HbGp). Electronic optical absorption, fluorescence emission and circular dichroism spectroscopy techniques, together with Gel-filtration chromatography, were used in order to evaluate the oligomeric dissociation as well as the autoxidation of HbGp as a function of the interaction with HPS. A peculiar behavior was observed for the HPS-HbGp interaction: a complex ferric species formation equilibrium was promoted, as a consequence of the autoxidation and oligomeric dissociation processes. At pH 7.0, HPS is more effective up to 1 mM while at pH 9.0 the surfactant effect is more intense above 1 mM. Furthermore, the interaction of HPS with HbGp was clearly less intense than the interaction of this hemoglobin with cationic (CTAC) and anionic (SDS) surfactants. Probably, this lower interaction with HPS is due to two factors: (i) the lower electrostatic attraction between the HPS surfactant and the protein surface ionic sites when compared to the electrostatic interaction between HbGp and cationic and anionic surfactants, and (ii) the low cmc of HPS, which probably reduces the interaction of the surfactant in the monomeric form with the protein. The present work emphasizes the importance of the electrostatic contribution in the interaction between ionic surfactants and HbGp. Furthermore, in the whole HPS concentration range used in this study, no folding and autoxidation decrease induced by this surfactant were observed. This is quite different from the literature data on the interaction between surfactants and tetrameric hemoglobins, that supports the occurrence of this behavior for the intracellular hemoglobins at low surfactant concentration range. Spectroscopic data are discussed and compared with the literature in order to improve the understanding of hemoglobin-surfactant interaction as well as the acid isoelectric point (pI) influence of the giant extracellular hemoglobins on their structure-activity relationship. (c) 2007 Elsevier B.V. All rights reserved.