Irreducibility of the moduli space of orthogonal instanton bundles on Pn

In order to obtain existence criteria for orthogonal instanton bundles on $\mathbb{P}^n$, we provide a bijection between equivalence classes of orthogonal instanton bundles with no global sections and symmetric forms. Using such correspondence we are able to provide explicit examples of orthogonal instanton bundles with no global sections on $\mathbb{P}^n$ and prove that every orthogonal instanton bundle with no global sections on $\mathbb{P}^n$ and charge $c \geq 2$ has rank $r \leq(n-1) c$. We also prove that when the rank $r$ of the bundles reaches the upper bound, $\mathcal{M}_{\mathbb{P}}^{\mathcal{O}}(c, r)$, the coarse moduli space of orthogonal instanton bundles with no global sections on $\mathbb{P}^n$, with charge $c \geq 2$ and rank $r$, is affine, smooth, reduced and irreducible. Last, we construct Kronecker modules to determine the splitting type of the bundles in $\mathcal{M}_{\mathbb{P} n}^{\mathcal{O}}(c, r)$, whenever is non-empty

Renin-Angiotensin System and Renal Allograft Long-Term Outcome: A Review

Recent developments in immunosuppressive therapy have reduced the loss of allografts from acute rejection, with a significant improvement in the one-year allograft survival. However, the introduction of more potent and selective new drug, had no effect on the development of chronic allograft dysfunction and the long-term outcome remains unchanged. Several and repeated different types of allograft insults such as delayed graft function, rejection episodes, drug nephrotoxicity, hypertension, dislipidemia determines a progressive damage with graft failure within a decade. There is no established maintenance immunosuppressive therapy that decreases chronic allograft dysfunction. The renin-angiotensin system is an important mediator in the pathogenesis of chronic progressive kidney diseases. Although the pathogenesis of chronic allograft nephropathy (CAN) is poorly understood, a reduced nephron function with hemodynamic changes associated with a cascade of inflammatory mediators, result in a chronic inflammatory process, progressive fibrosis and tissue remodeling. Recent evidence has shown beneficial effects of renin-angiotensin system blockade in the posttransplant with a decrease of blood pressure, proteinuria and inflammatory process

Xanthone biosynthesis and accumulation in calli and suspended cells of Hypericum androsaemum

Calli and suspended cells of Hypericum androsaemum accumulated high levels of 1,3,5,6 and 1,3,6,7 oxygenated xanthones. The major compounds include simple oxygenated xanthones or derivatives with prenyl, pyran or methoxyl groups, four of them being new natural compounds. A hypothetical biosynthetic scheme is proposed based on the isolated compounds and statistical analysis. Xanthone accumulation was influenced greatly by medium factors, namely hormone supplementation. Calli grown with 4.5 mM a-naphtaleneacetic acid (NAA) 2.3 mM kinetin (KIN) had the highest specific xanthone production (1.3% biomass dry weight (DW)), whereas suspended cells grown in similar medium accumulated a lower amount (0.87% DW). Calli displayed a negative linear relationship between total xanthone accumulation and NAA concentration, in the range of 4.5–22.5 mM. However, in this range the xanthone 1,3,6,7:1,3,5,6 ratio and the biomass production showed a positive linear relationship with NAA concentration. Substitution of 4.5 mM of NAA by the same molar amount of 2,4-dichlorophenoxyacetic acid (2,4-D), in the presence of 2.3 mM of KIN, caused a decrease in xanthone accumulation in calli. The use of N6-benzyladenine (BA) instead of KIN reduced xanthone production, independently of the auxin used. This effect was attenuated when both hormones were present.Fundação para a Ciência e a Tecnologia (FCT

The drinking of a Salvia officinalis infusion improves liver antioxidant status in mice and rats

In this study we evaluate the biosafety and bioactivity (antioxidant potential) of a traditional water infusion (tea) of common sage (Salvia officinalis L.) in vivo in mice and rats by quantification of plasma transaminase activities and liver GST and GR enzyme activities. The replacement of water by sage tea for 14 days in the diet of rodents did not affect the body weight and food consumption and did not induce liver toxicity. On the other hand, a significant increase of liver GST activity was observed in rats (24%) and mice (10%) of sage drinking groups. The antioxidant potential of sage tea drinking was also studied in vitro in a model using rat hepatocytes in primary culture. The replacement of drinking water with sage tea in the rats used as hepatocyte donors resulted in an improvement of the antioxidant status of rat hepatocytes in primary culture, namely a significant increase in GSH content and GST activity after 4 hours of culture. When these hepatocyte cultures were exposed to 0.75 or 1 mM of tert-butyl hydroperoxide for 1 hour, some protection against lipid peroxidation and GSH depletion was conferred by sage tea drinking. However, the cell death induced by t-BHP as shown by LDH leakage was not different from that observed in cultures from control animals. This study indicates that the compounds present in this sage preparation contain interesting bioactivities which improve the liver antioxidant potential.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/6942/2001, Programa Operacional “Ciência, Tecnologia, Inovação” (POCTI) - POCTI/AGR/43482/2001

Are the effects induced by increased temperature enhanced in Mytilus galloprovincialis submitted to air exposure?

Intertidal mussel species are frequently exposed to changes of environmental parameters related to tidal regimes that include a multitude of stressors that they must avoid or tolerate by developing adaptive strategies. In particular, besides air exposure during low tides, intertidal mussels are also subjected to warming and, consequently, to higher risk of desiccation. However, scarce information is available regarding the responses of mussels to tidal regimes, particularly in the presence of other stressors such as increased temperature. Investigating the impacts of such combination of conditions will allow to understand the possible impacts that both factors interaction may generate to these intertidal organisms. To this end, the present study evaluated the impacts of different temperatures (18 ºC and 21 ºC) on Mytilus galloprovincialis when continuously submersed or exposed to a tidal regime for 14 days. Results showed that in mussels exposed to increased temperature under submersion conditions, the stress induced was enough to activate mussels’ antioxidant defenses (namely glutathione peroxidase, GPx), preventing oxidative damage (lipid peroxidation, LPO; protein carbonylation, PC). In mussels exposed to tides at control temperature, metabolic capacity increased (electron transport system activity, ETS), and GPx was induced, despite resulting in increased LPO levels. Moreover, the combination of tides and temperature increase led to a significant decrease of lipid (LIP) content, activation of antioxidant defenses (superoxide dismutase, SOD; GPx) and increase of oxidized glutathione (GSSG), despite these mechanisms were not sufficient to prevent increased cellular damage. Therefore, the combination of increased temperature and air exposure induced higher oxidative stress in mussels. These findings indicate that increasing global warming could be more impacting to intertidal organisms compared to organisms continuously submersed. Furthermore, our results indicate that air exposure can act as a confounding factor when assessing the impacts of different stressors in organisms living in coastal systemspublishe

Water and methanolic extracts of Salvia officinalis protect HepG2 cells from t-BHP induced oxidative damage

Common sage (Salvia officinalis L., Lamiaceae) is an aromatic and medicinal plant well known for its antioxidant properties. Some in vivo studies have shown the biological antioxidant effects of sage. However, the intracellular antioxidant mechanisms of action are still poorly understood. In this study, we evaluated the cytoprotective effects of two sage extracts (a water and a methanolic extract) against tert-butyl hydroperoxide (t-BHP)-induced toxicity in HepG2 cells. The most abundant phenolic compounds present in the extracts were rosmarinic acid and luteolin-7-glucoside. Both extracts, when co-incubated with the toxicant, protected significantly HepG2 cells against cell death. The methanolic extract, with a higher content of phenolic compounds than the water extract, conferred better protection in this in vitro model of oxidative stress with liver cells. Both extracts, tested in a concentration that protects 80% against cell death (IC80), significantly prevented t-BHP-induced lipid peroxidation and GSH depletion, but not DNA damage assessed by the comet assay. The ability of sage extracts to reduce t-BHP-induced GSH depletion by 62% was probably the most relevant contributor to the observed cytoprotection. A good correlation between the above cellular effects of sage and the effects of their main phenolic compounds was found. When incubated alone for 5 h, sage extracts induced an increase in basal GSH levels of HepG2 cells, which indicates an improvement of the antioxidant potential of the cells. Compounds present in sage extracts other than phenolics may also contribute to this latter effect. Based in these results, it would be of interest to investigate whether sage has protective effects in suitable in vivo models of liver diseases, where it is known that oxidative stress is involved.Fundação para a Ciência e a Tecnologia (FCT) - SFRH/BD/6942/2001, POCI/AGR/62040/200

Synergistic Effects of Ocean Warming and Cyanide Poisoning in an Ornamental Tropical Reef Fish

UIDP/50017/2020 UIDB/50017/2020 UID/MAR/04292/2019 SFRH/BPD/117491/2016 SFRH/BPD/115298/2016 SFRH/BPD/99819/2014 PD/BD/52568/2014An array of anthropogenic pressures is affecting tropical ecosystems, posing major conservation challenges for scientists, stakeholders and populations. Illegal cyanide fishing is one of the major threats to Indo-Pacific coral reefs, targeting a multitude of colorful species for the marine aquarium trade as well as large-sized groupers and wrasses for the food fish trade. Ultimately, the continued use of this destructive practice as oceans warm may overload tropical ecosystems and result in irreversible ecological damage. Here we show that the impact of cyanide poisoning in an ornamental tropical marine fish is magnified under increased temperatures. A sole pulse exposure of 60 s to 50 mg L–1 of cyanide under current temperature (26°C) caused substantial mortality (50–100%) in eight species of Pomacentridae. The clownfish Amphiprion ocellaris was the most resistant, especially medium-sized fish [average total length and weight of 38 mm and 1.12 g; LC50 (95% CI) = 50.00 (46.76 − 53.24) mg L–1] that showed shorter recovery times and higher survival rates (%) when compared to small-sized ones [average total length and weight of 25 mm and 0.30 g; LC50 (95% CI) = 28.45 (20.17 − 36.72) mg L–1]. However, when the most resistant size-class was concomitantly exposed to a sub-lethal dosage of cyanide (25 mg L–1 instead of 50 mg L–1) and ocean warming scenarios for 2100 (+3°C and heat wave +6°C), survival rates (%) decreased to 60 and 20%, respectively, and recovery times increased in the worst case scenario. Mortality outbreaks, as well as vulnerability to predation, will likely expand in fish inhabiting coral reefs exposed to cyanide fishing unless stronger conservation measures are taken in tropical reefs to limit this destructive practice now and in the oceans of tomorrow.publishersversionpublishe