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21.
Gomes AA Silva-Júnior AC Oliveira EB Asad LM Reis NC Felzenszwalb I Kovary K Asad NR 《Redox report : communications in free radical research》2005,10(2):91-95
The involvement of reactive oxygen species (ROS) in the induction of DNA damage to Escherichia coli cells caused by UVC (254 nm) irradiation was studied. We verified the expression of the soxS gene induced by UVC (254 nm) and its inhibition by sodium azide, a singlet oxygen (1O2) scavenger. Additional results showed that a water-soluble carotenoid (norbixin) protects against the lethal effects of UVC. These results suggest that UVC radiation can also cause ROS-mediated lethality. 相似文献
22.
The roles of allopatric fragmentation and niche divergence in intraspecific lineage diversification in the common midwife toad (Alytes obstetricans) 下载免费PDF全文
23.
Hugo M. Botelho Sónia S. Leal Isabel Cardoso Kiran Yanamandra Ludmilla A. Morozova-Roche Günter Fritz Cláudio M. Gomes 《The Journal of biological chemistry》2012,287(50):42233-42242
S100A6 is a small EF-hand calcium- and zinc-binding protein involved in the regulation of cell proliferation and cytoskeletal dynamics. It is overexpressed in neurodegenerative disorders and a proposed marker for Amyotrophic Lateral Sclerosis (ALS). Following recent reports of amyloid formation by S100 proteins, we investigated the aggregation properties of S100A6. Computational analysis using aggregation predictors Waltz and Zyggregator revealed increased propensity within S100A6 helices HI and HIV. Subsequent analysis of Thioflavin-T binding kinetics under acidic conditions elicited a very fast process with no lag phase and extensive formation of aggregates and stacked fibrils as observed by electron microscopy. Ca2+ exerted an inhibitory effect on the aggregation kinetics, which could be reverted upon chelation. An FT-IR investigation of the early conformational changes occurring under these conditions showed that Ca2+ promotes anti-parallel β-sheet conformations that repress fibrillation. At pH 7, Ca2+ rendered the fibril formation kinetics slower: time-resolved imaging showed that fibril formation is highly suppressed, with aggregates forming instead. In the absence of metals an extensive network of fibrils is formed. S100A6 oligomers, but not fibrils, were found to be cytotoxic, decreasing cell viability by up to 40%. This effect was not observed when the aggregates were formed in the presence of Ca2+. Interestingly, native S1006 seeds SOD1 aggregation, shortening its nucleation process. This suggests a cross-talk between these two proteins involved in ALS. Overall, these results put forward novel roles for S100 proteins, whose metal-modulated aggregation propensity may be a key aspect in their physiology and function. 相似文献
24.
Alline Cristina Campos Fabricio Araújo Moreira Felipe Villela Gomes Elaine Aparecida Del Bel Francisco Silveira Guimar?es 《Philosophical transactions of the Royal Society of London. Series B, Biological sciences》2012,367(1607):3364-3378
Cannabidiol (CBD) is a major phytocannabinoid present in the Cannabis sativa plant. It lacks the psychotomimetic and other psychotropic effects that the main plant compound Δ9-tetrahydrocannabinol (THC) being able, on the contrary, to antagonize these effects. This property, together with its safety profile, was an initial stimulus for the investigation of CBD pharmacological properties. It is now clear that CBD has therapeutic potential over a wide range of non-psychiatric and psychiatric disorders such as anxiety, depression and psychosis. Although the pharmacological effects of CBD in different biological systems have been extensively investigated by in vitro studies, the mechanisms responsible for its therapeutic potential are still not clear. Here, we review recent in vivo studies indicating that these mechanisms are not unitary but rather depend on the behavioural response being measured. Acute anxiolytic and antidepressant-like effects seem to rely mainly on facilitation of 5-HT1A-mediated neurotransmission in key brain areas related to defensive responses, including the dorsal periaqueductal grey, bed nucleus of the stria terminalis and medial prefrontal cortex. Other effects, such as anti-compulsive, increased extinction and impaired reconsolidation of aversive memories, and facilitation of adult hippocampal neurogenesis could depend on potentiation of anandamide-mediated neurotransmission. Finally, activation of TRPV1 channels may help us to explain the antipsychotic effect and the bell-shaped dose-response curves commonly observed with CBD. Considering its safety profile and wide range of therapeutic potential, however, further studies are needed to investigate the involvement of other possible mechanisms (e.g. inhibition of adenosine uptake, inverse agonism at CB2 receptor, CB1 receptor antagonism, GPR55 antagonism, PPARγ receptors agonism, intracellular (Ca2+) increase, etc.), on CBD behavioural effects. 相似文献
25.
Background
Exposure of cells to environmental stress conditions can lead to the interruption of several intracellular processes, in particular those performed by macromolecular complexes such as the spliceosome. 相似文献26.
Nitric oxide plays an important role in various biological processes, such as neurotransmission, blood pressure control, immunological responses, and antioxidant action. The control of its local concentration, which is crucial for obtaining the desired effect, can be achieved with exogenous NO-carriers. Coordination compounds, in particular ruthenium(III) and (II) amines, are good NO-captors and -deliverers. The chemical and photochemical properties of several ruthenium amine complexes as NO-carriers in vitro and in vivo have been reviewed. These nitrosyl complexes can stimulate mice hippocampus slices, promote the lowering of blood pressure in several in vitro and in vivo models, and control Trypanosoma cruzi and Leishmania major infections, and they are also effective against tumor cells in different models of cancer. These complexes can be activated chemically or photochemically, and the observed biological effects can be attributed to the presence of NO in the compound. Their efficiencies are explained on the basis of the [RuIINO+]3+/[RuIINO0]2+ reduction potential, the specific rate constant for NO liberation from the [RuNO]2+ moiety, and the quantum yield of NO release. 相似文献
27.
Okino Luci Kimie Machado Kátia Maria Gomes Fabris Carla Bononi Vera Lúcia Ramos 《World journal of microbiology & biotechnology》2000,16(8-9):889-893
A total of 116 strains of Brazilian tropical rainforest basidiomycetes were evaluated in terms of their ability to oxidize
the dye rhemazol brilliant blue R (RBBR) and guaiacol. Laccase and peroxidase activities were detected by the drop test using
solutions of α-naphthol and pyrogallol, respectively. RBBR and guaiacol oxidation occurred in 96.6 and 87.1% of the strains
tested, respectively. One hundred strains oxidized both substrates. In the drop test, most strains presented laccase (96.6%)
and peroxidase (92.2%) activity. The quick screening method used here can be useful to identify ligninolytic fungal strains
to be used in various biotechnological applications.
This revised version was published online in November 2006 with corrections to the Cover Date. 相似文献
28.
Alexandre Medeiros do Carmo Fabiana Maria Santos Carmen Lucia Ortiz-Agostinho Iêda Nishitokukado Cintia S. Frota Flavia Ubeda Gomes André Zonetti de Arruda Leite Claudio Sérgio Pannuti Lucy Santos Vilas Boas Magaly Gemio Teixeira Aytan Miranda Sipahi 《PloS one》2014,9(11)
Background
Cytomegalovirus is highly prevalent virus and usually occurs in immunocompromised patients. The pathophysiology and treatment of inflammatory bowel disease often induce a state of immunosuppression. Because this, there are still doubts and controversies about the relationship between inflammatory bowel disease and cytomegalovirus.Aim
Evaluate the frequency of cytomegalovirus in patients with inflammatory bowel disease and identify correlations.Methods
Patients with inflammatory bowel disease underwent an interview, review of records and collection of blood and fecal samples. The search for cytomegalovirus was performed by IgG and IgM blood serology, by real-time PCR in the blood and by qualitative PCR in feces. Results were correlated with red blood cell levels, C-reactive protein levels, erythrocyte sedimentation rates and fecal calprotectin levels for each patient.Results
Among the 400 eligible patients, 249 had Crohn''s disease, and 151 had ulcerative colitis. In the group of Crohn''s disease, 67 of the patients had moderate or severe disease, but 126 patients presented with active disease, based on the evaluation of the fecal calprotectin. In patients with ulcerative colitis, only 21 patients had moderate disease, but 76 patients presented with active disease, based on the evaluation of the fecal calprotectin. A large majority of patients had positive CMV IgG. Overall, 10 patients had positive CMV IgM, and 9 patients had a positive qualitative detection of CMV DNA by PCR in the feces. All 400 patients returned negative results after the quantitative detection of CMV DNA in blood by real-time PCR. Analyzing the 19 patients with active infections, we only found that such an association occurred with the use of combined therapy (anti-TNF-alpha + azathioprine)Conclusion
The findings show that latent cytomegalovirus infections are frequent and active cytomegalovirus infection is rare. We did not find any association between an active infection of CMV and inflammatory bowel disease activity. 相似文献29.
Santos ME das C L E Silva F Gomes KB Fernandes AP Freitas FR Faria MC Mota AP Carvalho MG 《Molecular biology reports》2011,38(5):3361-3366
Peripheral arterial disease (PAD) is an atherosclerotic disturbance characterized by a progressive obstruction of lower limb
arteries. Many risk factors associated with PAD development have being reported in the literature. The present study aimed
to investigate whether mutations in the methylenetetrahydrofolate reductase (MTHFR) or in the cystathionine beta synthase
(CBS) genes are associated with higher levels of homocysteine and the risk of PAD in patients from Brazil. This study analyzed
39 patients with PAD and 32 without PAD in whom risk factors and C677T mutations in the MTHFR gene and both 844ins68 and T833C
mutations in the CBS gene were investigated. Although higher levels of homocysteine could be observed in patients with PAD
compared to controls, no association between the increase of homocysteine and the frequency of C677T, 844ins68, and T833C
mutations could be observed. The results suggest that these mutations do not appear to be related to either homocysteine levels
or the development of the disease. However, hyperhomocysteinemia and smoking are important factors in PAD development. 相似文献
30.
Lopes M Gomes N Gonçalves C Coelho MA Mota M Belo I 《Letters in applied microbiology》2008,46(2):255-260
Aims: To study the cellular growth and morphology of Yarrowia lipolytica W29 and its lipase and protease production under increased air pressures. Methods and Results: Batch cultures of the yeast were conducted in a pressurized bioreactor at 4 and 8 bar of air pressure and the cellular behaviour was compared with cultures at atmospheric pressure. No inhibition of cellular growth was observed by the increase of pressure. Moreover, the improvement of the oxygen transfer rate (OTR) from the gas to the culture medium by pressurization enhanced the extracellular lipase activity from 96·6 U l?1 at 1 bar to 533·5 U l?1 at 8 bar. The extracellular protease activity was reduced by the air pressure increase, thereby eliciting further lipase productivity. Cell morphology was slightly affected by pressure, particularly at 8 bar, where cells kept the predominant oval form but decreased in size. Conclusions: OTR improvement by total air pressure rise up to 8 bar in a bioreactor can be applied to the enhancement of lipase production by Y. lipolytica. Significance and Impact of the Study: Hyperbaric bioreactors can be successfully applied for yeast cells cultivation, particularly in high‐density cultures used for enzymes production, preventing oxygen limitation and consequently increasing overall productivity. 相似文献