Role of antioxidant treatment on DNA and lipid damage in the brain of rats subjected to a chemically induced chronic model of tyrosinemia type II

Tyrosine levels are abnormally elevated in tissues and body fluids of patients with inborn errors of tyrosine metabolism. Tyrosinemia type II, which is caused by tyrosine aminotransferase deficiency, provokes eyes, skin, and central nervous system disturbances in affected patients. However, the mechanisms of brain damage are still poorly known. Considering that studies have demonstrated that oxidative stress may contribute, along with other mechanisms, to the neurological dysfunction characteristic of hypertyrosinemia, in the present study we investigated the effects of antioxidant treatment (NAC and DFX) on DNA damage and oxidative stress markers induced by chronic administration of l-tyrosine in cerebral cortex, hippocampus, and striatum of rats. The results showed elevated levels of DNA migration, and thus DNA damage, after chronic administration of l-tyrosine in all the analyzed brain areas, and that the antioxidant treatment was able to prevent DNA damage in cerebral cortex and hippocampus. However, the co-administration of NAC plus DFX did not prevent the DNA damage in the striatum. Moreover, we found a significant increase in thiobarbituric acid-reactive substances (TBA-RS) and DCFH oxidation in cerebral cortex, as well as an increase in nitrate/nitrite levels in the hippocampus and striatum. Additionally, the antioxidant treatment was able to prevent the increase in TBA-RS levels and in nitrate/nitrite levels, but not the DCFH oxidation. In conclusion, our findings suggest that reactive oxygen and nitrogen species and oxidative stress can play a role in DNA damage in this disorder. Moreover, NAC/DFX supplementation to tyrosinemia type II patients may represent a new therapeutic approach and a possible adjuvant to the current treatment of this disease.     

Antitumor activity of resveratrol is independent of Cu(II) complex formation in MCF-7 cell line

Resveratrol (Rsv) is widely reported to possess anticarcinogenic properties in a plethora of cellular and animal models having limited toxicity toward normal cells. In the molecular level, Rsv can act as a suppressive agent for several impaired signaling pathways on cancer cells. However, Fukuhara and Miyata have shown a non-proteic reaction of Rsv, which can act as a prooxidant agent in the presence of copper (Cu), causing cellular oxidative stress accompanied of DNA damage. After this discovery, the complex Rsv-Cu was broadly explored as an antitumor mechanism in multiples tumor cell lines. The aim of the study is to explore the anticarcinogenic behavior of resveratrol–Cu(II) complex in MCF-7 cell line.Selectivity of Rsv binding to Cu ions was analyzed by HPLC and UV–VIS. The cells were enriched with concentrations of 10 and 50 µM CuSO₄ solution and treated with 25 µM of Rsv. Copper uptake after enrichment of cells, as its intracellular distribution in MCF-7 line, was scanned by ICP-MS and TEM-EDS. Cell death and intracellular ROS production were determined by flow cytometry.Different from the extracellular model, no relationship of synergy between Rsv–Cu(II) and reactive oxidative species (ROS) production was detected in vitro. ICP-MS revealed intracellular copper accumulation to both chosen concentrations (0.33 ± 0.09 and 1.18 ± 0.13 ppb) but there is no promotion of cell death by Rsv–Cu(II) complex. In addition, significant attenuation of ROS production was detected when cells were exposed to CuSO₄ after Rsv treatment, falling from 7.54% of ROS production when treated only with Rsv to 3.07 and 2.72% with CuSO₄.Based on these findings antitumor activity of resveratrol when in copper ions presence, is not mediated by Rsv-Cu complex formation in MCF-7 human cell line, suggesting that the antitumoral reaction is dependent of a cancer cellular model.     

Incidence and diversity of arbuscular mycorrhizal fungi and successor herbaceous plants in an agro-system irrigated with produced water

The purpose of this study was to evaluate the diversity of herbaceous plants and arbuscular mycorrhizal fungi following the cultivation of sunflower (Helianthus annuus L., cv. BRS 321) irrigated with produced water. The sunflower plants were irrigated during three successive cycles with different types of water: produced water obtained through simple filtration (PWSF), and secondly, produced water treated by reverse osmosis (PWRO), and the control with groundwater from the aquifer Açu (WCA). In June 2014, five months after the final harvest, the treatments were evaluated in terms of the diversity of successor plants and their roots colonized by arbuscular mycorrhiza (AM); and samples of soil, in which the following were measured: the spore abundance of AM fungi, the levels of glomalin in easily extracted glomalin and total glomalin. Of a total of eighteen species of herbaceous plants which were identified in the experimental field, Dactyloctenium aegyptium was related with the use of PWSF, Panicum sp. and Diodella apiculata with the use of PWRO, and Trianthema portulacastrum and Eragrostis tenella with the control WCA. The diversity of AM fungi was affected by irrigation with PWSF, in which two species of Acaulospora, one species of Gigaspora and species of Paraglomus were absent, compared to the treatment with PWRO. Acaulospora sp.1 was related with the WCA control as an indicator species. The use of produced water which had undergone reverse osmosis had a short-term effect on the content of glomalin which is easily extractable from the soil but did not change the mycorrhization rates of plants. These results enable us to infer that irrigation with produced water leads to a reduction in the diversity of herbaceous plants and of arbuscular mycorrhizal fungi in the soil, confirming the importance of monitoring agro-systems irrigated with residual water.     

Seven new species of Cis Latreille (Coleoptera: Ciidae) from southern Africa

Here we describe seven new species of Cis Latreille from southern Africa: Cis aster sp. nov., Cis makebae sp. nov., Cis mandelai sp. nov., Cis masekelai sp. nov., Cis neserorum sp. nov., Cis stalsi sp. nov. and Cis urbanae sp. nov. We also provide information on their host fungi and geographic distributions.     

Abiotic barriers limit tree invasion but do not hamper native shrub recruitment in invaded stands

The interplay between the invasion of alien plant species and re-colonization of native plant species is important for conservation. Sandy coastal plains (called restinga in Brazil) were used as a model system to explore the abiotic barriers that potentially limit the initial establishment of alien and native woody plants in invaded and non-invaded areas. The study tested the influence of light availability, soil type and litter layer on recruitment of a wind-dispersed alien tree (Casuarina equisetifolia) and two bird-dispersed native shrubs under a Casuarina stand and in the preserved restinga. The effect of soil type and the physical and allelopathic effects of Casuarina litter on seedling emergence of the three species were also evaluated under greenhouse conditions. Low dispersal associated with low seedling emergence and zero survival of young plants (mainly due to microhabitat conditions) apparently prevents the spread of Casuarina in the preserved restinga. The main cause of low recruitment of native species in the Casuarina stand was the physical barrier of the litter. However, if seeds overcome this physical barrier, the presence of litter improves seedling emergence and survival of young plants, mainly because the litter increases soil moisture. Sowing seeds below litter and planting young plants of native shrubs on litter can improve the re-colonization of native plants in invaded areas. In conclusion, Casuarina invasion on sandy coastal plains is strongly limited by abiotic barriers, but anthropogenic disturbances are altering the key processes that naturally make the restinga resistant to invasion.     

Biochemical studies with DNA polymerase beta and DNA polymerase beta-PAK of Trypanosoma cruzi suggest the involvement of these proteins in mitochondrial DNA maintenance

Mammalian DNA polymerase beta is a nuclear enzyme involved in the base excision and single-stranded DNA break repair pathways. In trypanosomatids, this protein does not have a defined cellular localization, and its function is poorly understood. We characterized two Trypanosoma cruzi proteins homologous to mammalian DNA polymerasebeta, TcPolbeta and TcPolbetaPAK, and showed that both enzymes localize to the parasite kinetoplast. In vitro assays with purified proteins showed that they have DNA polymerization and deoxyribose phosphate lyase activities. Optimal conditions for polymerization were different for each protein with respect to dNTP concentration and temperature, and TcPolbetaPAK, in comparison to TcPolbeta, conducted DNA synthesis over a much broader pH range. TcPolbeta was unable to carry out mismatch extension or DNA synthesis across 8-oxodG lesions, and was able to discriminate between dNTP and ddNTP. These specific abilities of TcPolbeta were not observed for TcPolbetaPAK or other X family members, and are not due to a phenylalanine residue at position 395 in the C-terminal region of TcPolbeta, as assessed by a site-directed mutagenesis experiment reversing this residue to a well conserved tyrosine. Our data suggest that both polymerases from T. cruzi could cooperate to maintain mitochondrial DNA integrity through their multiple roles in base excision repair, gap filling and translesion synthesis.     

Variability in essential-oil composition of Piper marginatum sensu lato

This paper contains data on the chemical composition of the essential oils of 22 leaf samples of Piper marginatum Jacq. collected in different areas and ecosystems of the brazilian Amazon, as well as an overview of the available literature. The species presents a large synonymy based on their different leaf characteristics and distinct scents where some of them smell like anise or very close compounds. By GC, GC/MS, and cluster analysis, we identified seven chemotypes for the leaf oils. The main components found in chemotype I were safrole (1) and 3,4-(methylenedioxy)propiophenone (2). The chemotype II was dominated by 3,4-(methylenedioxy)propiophenone (2) and p-mentha-1(7),8-diene (10). The major compounds identified in chemotype III were 3,4-(methylenedioxy)propiophenone (2), myristicin (3), (E)-beta-ocimene (11), and gamma-terpinene (12). In the chemotype IV, the principal constituents were beta-caryophyllene (13), alpha-copaene (14), and 3,4-(methylenedioxy)propiophenone (2). The chemotype V was dominated by (E)-isoosmorhizole (6), (E)-anethole (8), and isoosmorhizole (7). The main compounds found in the chemotype VI were 2-methoxy-4,5-(methylenedioxy)propiophenone (4), methoxy-4,5-(methylenedioxy)propiophenone isomer 5, and (E)-isoosmorhizole (6). The major constituents in chemotype VII were beta-caryophyllene (13), bicyclogermacrene (15), and (E)-asarone (9).     

Intra- and interspecific variation of cuticular hydrocarbon composition in two Ectatomma species (Hymenoptera: Formicidae) based on Fourier transform infrared photoacoustic spectroscopy

We have been able to discriminate different castes and sexes of ants in the same colony by measuring cuticular hydrocarbon levels with Fourier transform infrared photoacoustic spectroscopy, compared by canonical discriminant function analysis. We have now applied this methodology to various colonies of two species of ants of the genus Ectatomma in the Brazilian Cerrado. There were clear interspecific differences in cuticular hydrocarbons of these ants, with a small intraspecific variation. The differences between colonies were greater in E. brunneum than in E. vizottoi. Genetic differences among the colonies and species were well estimated by Fourier transform infrared photoacoustic spectroscopy and statistical analyses.