Preparation and Application of Nb2O5 Nanofibers in CO2 Photoconversion.

Increasing global warming due to NOx, CO2, and CH4, is significantly harming ecosystems and life worldwide. One promising methodology is converting pollutants into valuable chemicals via photocatalytic processes (by reusable photocatalysts). In this context, the present work aimed to produce a Nb2O5 photocatalyst nanofiber system by electrospinning to convert CO2. Based on the collected data, the calcination at 600 ∘C for 2 h resulted in the best condition to obtain nanofibers with homogeneous surfaces and an average diameter of 84 nm. As a result, the Nb2O5 nanofibers converted CO2 mostly into CO and CH4, reaching values around 8.5 µmol g-1 and 0.55 µmol g-1, respectively.

Lithium and memantine improve spatial memory impairment and neuroinflammation induced by ß-amyloid 1-42 oligomers in rats.

Alzheimer's disease (AD) is the most common cause of dementia in the elderly. The main hallmarks of this disease include progressive cognitive dysfunction and an accumulation of soluble oligomers of ß-amyloid (Aß) 1-42 peptide. In this research, we show the effects of lithium and memantine on spatial memory and neuroinflammation in an Aß1-42 oligomers-induced animal model of dementia in rats. Aß 1-42 oligomers were administered intrahippocampally to male wistar rats to induce dementia. Oral treatments with memantine (5mg/kg), lithium (5mg/kg), or both drugs in combination were performed over a period of 17days. 14days after the administration of the Aß1-42 oligomers, the radial arm-maze task was performed. At the end of the test period, the animals were euthanized, and the frontal cortex and hippocampus were removed for use in our analysis. Our results showed that alone treatments with lithium or memantine ameliorate the spatial memory damage caused by Aß1-42. The animals that received combined doses of lithium and memantine showed better cognitive performance in their latency time and total errors to find food when compared to the results from alone treatments. Moreover, in our study, lithium and/or memantine were able to reverse the decreases observed in the levels of interleukin (IL)-4 that were induced by Aß1-42 in the frontal cortex. In the hippocampus, only memantine and the association of memantine and lithium were able to reverse this effect. Alone doses of lithium and memantine or the association of lithium and memantine caused reductions in the levels of IL-1ß in the frontal cortex and hippocampus, and decreased the levels of TNF-α in the hippocampus. Taken together, these data suggest that lithium and memantine might be a potential therapy against cognitive impairment and neuroinflammation induced by Aß1-42, and their association may be a promising alternative to be investigated in the treatment of AD-like dementia.

A survey of indigenous microbial hydrocarbon degradation genes in soils from Antarctica and Brazil.

Total community DNA from 29 noncontaminated soils and soils impacted by petroleum hydrocarbons and chloro-organics from Antarctica and Brazil were screened for the presence of nine catabolic genes, encoding alkane monooxygenase or aromatic dioxygenases, from known bacterial biodegradation pathways. Specific primers and probes targeting alkane monooxygenase genes were derived from Pseudomonas putida ATCC 29347 (Pp alkB), Rhodococcus sp. strain Q15 (Rh alkB1, Rh alkB2), and Acinetobacter sp. ADP-1 (Ac alkM). In addition, primers and probes detecting aromatic dioxygenase genes were derived from P. putida ATCC 17484 (ndoB), P. putida F1 (todC1), P. putida ATCC 33015 (xylE and cat23), and P. pseudoalcaligenes KF707 (bphA). The primers and probes were used to analyze total community DNA extracts by using PCR and hybridization analysis. All the catabolic genes, except the Ac alkM, were detected in contaminated and control soils from both geographic regions, with a higher frequency in the Antarctic soils. The alkane monooxygenase genes, Rh alkB1 and Rh alkB2, were the most frequently detected alk genes in both regions, while Pp alkB was not detected in Brazil soils. Genes encoding the aromatic dioxygenases toluene dioxygenase (todC1) and biphenyl dioxygenase (bphA) were the most frequently detected in Antarctica, and todC1 and catechol-2,3-dioxygenase (cat23) were the most frequent in Brazil soils. Hybridization analysis confirmed the PCR results, indicating that the probes used had a high degree of homology to the genes detected in the soil extracts and were effective in detecting biodegradative potential in the indigenous microbial population.

Prevalence of alkane monooxygenase genes in Arctic and Antarctic hydrocarbon-contaminated and pristine soils.

Abstract The prevalence of four alkane monooxygenase genotypes (Pseudomonas putida GPo1, Pp alkB; Rhodococcus sp. strain Q15, Rh alkB1 and Rh alkB2; and Acinetobacter sp. strain ADP-1, Ac alkM) in hydrocarbon-contaminated and pristine soils from the Arctic and Antarctica were determined by both culture-independent (PCR hybridization analyses) and culture-dependent (colony hybridization analyses) molecular methods, using oligonucleotide primers and DNA probes specific for each of the alk genotypes. PCR hybridization of total soil community DNA detected the rhodococcal alkB genotypes in most of the contaminated (Rh alkB1, 18/20 soils; Rh alkB2, 13/20) and many pristine soils (Rh alkB1, 9/10 soils; Rh alkB2, 7/10), while Pp alkB was generally detected in the contaminated soils (15/20) but less often in pristine soils (5/10). Ac alkM was rarely detected in the soils (1/30). The colony hybridization technique was used to determine the prevalence of each of the alk genes and determine their relative abundance in culturable cold-adapted (5 degrees C) and mesophilic populations (37 degrees C) from eight of the polar soils. The cold-adapted populations, in general, possessed relatively higher percentages of the Rh alkB genotypes (Rh alkB1, 1.9% (0.55); Rh alkB2, 2.47% (0.89)), followed by the Pp alkB (1.13% (0.50)), and then the Ac alkM (0.53% (0.36)). The Rh alkB1 genotype was clearly more prevalent in culturable cold-adapted bacteria (1.9% (0.55)) than in culturable mesophiles (0.41 (0.55)), suggesting that cold-adapted bacteria are the predominant organisms possessing this genotype. Overall, these results indicated that (i) Acinetobacter spp. are not predominant members of polar alkane degradative microbial communities, (ii) Pseudomonas spp. may become enriched in polar soils following contamination events, and (iii) Rhodococcus spp. may be the predominant alkane-degradative bacteria in both pristine and contaminated polar soils.