In vitro protective effect and antioxidant mechanism of Resveratrol induced by Dapsone Hydroxylamine in human cells

Dapsone (DDS) hydroxylamine metabolites cause oxidative stress- linked adverse effects in patients, such as methemoglobin formation and DNA damage. This study evaluated the ameliorating effect of the antioxidant resveratrol (RSV) on DDS hydroxylamine (DDSNHOH) mediated toxicity in vitro using human erythrocytes and lymphocytes. The antioxidant mechanism was also studied using in-silico methods. In addition, RSV provided intracellular protection by inhibiting DNA damage in human lymphocytes induced by DDS-NHOH. However, whilst pretreatment with RSV (10-1000 μM significantly attenuated DDS-NHOH-induced methemoglobinemia, but it was not only significantly less effective than methylene blue (MET), but also post-treatment with RSV did not reverse methemoglobin formation, contrarily to that observed with MET. DDS-NHOH inhibited catalase (CAT) activity and reactive oxygen species (ROS) generation, but did not alter superoxide dismutase (SOD) activity in erythrocytes. Pretreatment with RSV did not alter these antioxidant enzymes activities in erythrocytes treated with DDS-NHOH. Theoretical calculations using density functional theory methods showed that DDS-NHOH has a pro-oxidant effect, whereas RSV and MET have antioxidant effect on ROS. The effect on methemoglobinemia reversion for MET was significantly higher than that of RSV. These data suggest that the pretreatment with resveratrol may decrease heme-iron oxidation and DNA damage through reduction of ROS generated in cells during DDS therapy

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear un derstanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5–7 vast areas of the tropics remain understudied.8–11 In the American tropics, Amazonia stands out as the world’s most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepre sented in biodiversity databases.13–15 To worsen this situation, human-induced modifications16,17 may elim inate pieces of the Amazon’s biodiversity puzzle before we can use them to understand how ecological com munities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple or ganism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region’s vulnerability to environmental change. 15%–18% of the most ne glected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lostinfo:eu-repo/semantics/publishedVersio

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Pervasive gaps in Amazonian ecological research

Biodiversity loss is one of the main challenges of our time,1,2 and attempts to address it require a clear understanding of how ecological communities respond to environmental change across time and space.3,4 While the increasing availability of global databases on ecological communities has advanced our knowledge of biodiversity sensitivity to environmental changes,5,6,7 vast areas of the tropics remain understudied.8,9,10,11 In the American tropics, Amazonia stands out as the world's most diverse rainforest and the primary source of Neotropical biodiversity,12 but it remains among the least known forests in America and is often underrepresented in biodiversity databases.13,14,15 To worsen this situation, human-induced modifications16,17 may eliminate pieces of the Amazon's biodiversity puzzle before we can use them to understand how ecological communities are responding. To increase generalization and applicability of biodiversity knowledge,18,19 it is thus crucial to reduce biases in ecological research, particularly in regions projected to face the most pronounced environmental changes. We integrate ecological community metadata of 7,694 sampling sites for multiple organism groups in a machine learning model framework to map the research probability across the Brazilian Amazonia, while identifying the region's vulnerability to environmental change. 15%–18% of the most neglected areas in ecological research are expected to experience severe climate or land use changes by 2050. This means that unless we take immediate action, we will not be able to establish their current status, much less monitor how it is changing and what is being lost

Potential environmental and host gender influences on prevalence of Haemogregarina platessae (Adeleorina:Haemogregarinidae) and suspected Haemohormidium terraenovae (incertae sedis) in Brazilian flounder from the Patos Lagoon Estuary, southern Brazil

Flounder, Paralichthys orbignyanus (Valenciennes), were captured in polluted and non-polluted sites within the Patos Lagoon Estuary, southern Brazil, over four seasons. Blood films showed a high prevalence of infection with a haemogregarine, or mixed parasitaemias of this and an organism resembling Haemohormidium terraenovae So, 1972. Haemogregarine gamont stages conformed to existing descriptions of Desseria platessae (Lebailly, 1904) Siddall, 1995 from flatfishes, but intraerythrocytic division of meronts was observed, leading to the recommendation for nomenclatural correction, placing the haemogregarine in the genus Haemogregarina (sensu lato) Danilewsky, 1885. Statistical analyses suggested that although sample sizes were small, infections with meront stages, immature and mature gamonts were all influenced by site, and possibly therefore, by pollution. Season also appeared to determine likelihood of infection with meronts and immature gamonts, but not mature gamonts, while adult fish gender apparently affected infection with immature and mature gamonts, but not meronts. The H. terraenovae-like organism exhibited unusual extracellular forms and did not match closely with the type description of H. terraenovae; precise identification was therefore difficult. Data analyses suggested that parasitism by this organism was influenced by site and fish gender, since females and males from non-polluted water were infected, but only females from the polluted site. Season was also important and significantly more adult fish of both sexes were infected with this parasite in the Brazilian summer and autumn, compared with winter and spring. Finally, these appeared to be the first observations of Haemogregarina platessae, and possibly H. terraenovae, from the southern hemisphere

Sedimentary PAH and oxidative stress biomarkers responses on Namalycastis abiuma (Polychaeta: Nereididae) from an urbanized Amazon estuary

Ministry of Science, Brazil, Technology and Innovation/National Council of Scientific and Technological Development/National Institute of Technology:Tropical Marine Environments, Brazil (565054/2010-4; MCTI / CNPq/INCT-Ambientes Marinhos Tropicais).Universidade Federal do Pará. Instituto de Geociências. Faculdade de Oceanografia. Laboratório de Oceanografia Química. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Geociências. Faculdade de Oceanografia. Laboratório de Oceanografia Química. Belém, PA, Brazil.Universidade Federal do Pará. Laboratório de Pesquisa e Monitoramento Ambiental. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Geociências. Faculdade de Oceanografia. Laboratório de Oceanografia Química. Belém, PA, Brazil.Universidade Federal do Pará. Instituto de Geociências. Faculdade de Oceanografia. Laboratório de Oceanografia Química. Belém, PA, Brazil.Ministério da Saúde. Secretaria de Ciência, Tecnologia, Inovação e Insumos Estratégicos. Instituto Evandro Chagas. Ananindeua, PA, Brasil.Universidade Federal do Pará. Instituto de Geociências. Faculdade de Oceanografia. Laboratório de Oceanografia Física. Belém, PA, Brazil.Universidade Federal do Pará. Laboratório de Pesquisa e Monitoramento Ambiental. Belém, PA, Brazil.Contamination by polycyclic aromatic hydrocarbons (PAH) in sediments and oxidative stress biomarkers responses (glutathione-S-transferase activity—GST and lipoperoxidation—LPO) on the polychaetes Namalycastis abiuma were screened along the urbanized margin of the Guajará Estuary, Brazilian Amazon coast, during dry and rainy seasons. Total 16 priority PAH concentrations ranged from 17 to 386 ng g−1 dry sediment, with higher values during the dry season. High molecular weight PAHs predominated during dry season and were probably originated from fossil fuel burning. Increased naphthalene and anthracene concentrations were noted when the maximum river flow was recorded and suggest diffuse sources from drainage of contaminated surfaces. Ecotoxicological PAH risks were low according to international sediment quality indices. Nevertheless, PAH toxicity equivalency was around 10-fold higher nearer the oil terminal than alongside the estuary. Highest GST activities at the oil terminal and industrial sites coincided with the rainy season, and combined with hydrochemical and sedimentary conditions thought to promote PAH bioavailability and a prolonged toxicant exposure. LPO approached similar levels in both seasons, suggesting that enzymatic activities were sufficient to uphold the prooxidants exposure. This result indicates that the overall estuarine condition exerts subtle oxidative stress on a keystone species and matches the low PAH ecotoxicological risks. Depositional margins within the mangrove areas and port operation are susceptible to an enhanced PAH accumulation and need special surveillance

In Vitro Protective Effect and Antioxidant Mechanism of Resveratrol Induced by Dapsone Hydroxylamine in Human Cells.

Dapsone (DDS) hydroxylamine metabolites cause oxidative stress- linked adverse effects in patients, such as methemoglobin formation and DNA damage. This study evaluated the ameliorating effect of the antioxidant resveratrol (RSV) on DDS hydroxylamine (DDS-NHOH) mediated toxicity in vitro using human erythrocytes and lymphocytes. The antioxidant mechanism was also studied using in-silico methods. In addition, RSV provided intracellular protection by inhibiting DNA damage in human lymphocytes induced by DDS-NHOH. However, whilst pretreatment with RSV (10-1000 μM significantly attenuated DDS-NHOH-induced methemoglobinemia, but it was not only significantly less effective than methylene blue (MET), but also post-treatment with RSV did not reverse methemoglobin formation, contrarily to that observed with MET. DDS-NHOH inhibited catalase (CAT) activity and reactive oxygen species (ROS) generation, but did not alter superoxide dismutase (SOD) activity in erythrocytes. Pretreatment with RSV did not alter these antioxidant enzymes activities in erythrocytes treated with DDS-NHOH. Theoretical calculations using density functional theory methods showed that DDS-NHOH has a pro-oxidant effect, whereas RSV and MET have antioxidant effect on ROS. The effect on methemoglobinemia reversion for MET was significantly higher than that of RSV. These data suggest that the pretreatment with resveratrol may decrease heme-iron oxidation and DNA damage through reduction of ROS generated in cells during DDS therapy

Chemoprotection of lipoic acid against microcystin-induced toxicosis in common carp (Cyprinus carpio, Cyprinidae)

This paper evaluated the chemoprotective effect of lipoic acid (LA) against microcystin (MC) toxicity in carp Cyprinus carpio. To determine the LA dose and the time necessary for the induction of three different classes (alpha, mu and pi) of glutathione S-transferase (GST) gene transcription, carp were i.p. injected with 40 mg/kg lipoic acid solution. A group was killed 24 h after the first i.p. injection (condition 1); another group received two i.p. injections with a 24 h of interval between each one and was killed 48 h after the first injection (condition 2) and a third group received one i.p. injection and was killed 48 h latter (condition 3).Results showed that LA was effective in promoting an increase in GSTs gene transcription in liver only in the condition 2. A second experiment was done, where carp pre-treated with LA (condition 2) were gavaged twice with a 24 h interval with 50 μg MC/kg. Ninety-six hours after experiment beginning, carp were killed, and organs were dissected. Results of GST activity in liver and brain suggest that LA can be a useful chemoprotection agent against MC induced toxicity, stimulating detoxification through the increment of GST activity (brain) or through reversion of GST inhibition (liver)

Comparative effect of post-treatment with resveratrol (RSV) or methylene blue (MET) on methemoglobin formation induced by DDS-NHOH.

<p>Erythrocytes were incubated for 1 h with DDS-NHOH (2.5 μg/mL), then these cells were incubated with RSV (100μM) for 1 h or MET(40 nM). Data are reported as mean ± S.E.M. *P < 0.05 compared to methanol group. ^#P < 0.05 compared to DDS-NHOH group.</p