Biosorbents for solid-phase extraction of toxic elements in waters

Some trace metals are highly toxic for the environment. There is therefore a need for reliable methods for the determination of metals at trace levels. To this end, new sample pretreatment methods such as separation, preconcentration and speciation prior to the determination of metal ions have developed rapidly. Biosorption has become a major tool for solid-phase extraction methods. This review covers selected biosorbents such as algae, bacteria, filamentous fungi and yeasts, as new sorbents used in the solid-phase extraction of metal ions from various water sample matrices. A survey of the literature over 2004-2014 shows possible applications of selected new sorbents available for use in trace metal analysis in waters using solidphase extraction. We highlight the preconcentration of the toxic elements prior to their determination by atomic spectrometry.     

A motley of possible therapies of the COVID-19: reminiscing the origin of the pandemic

Environmental Science and Pollution Research - The 2019 outbreak of corona virus disease began from Wuhan (China), transforming into a leading pandemic, posing an immense threat to the global...     

TiO2-NPs and cadmium co-exposure: in vitro assessment of genetic and genomic DNA damage on Dicentrarchus labrax embryonic cells

Environmental Science and Pollution Research - The increased titanium dioxide nanoparticles (TiO2-NPs) spread and their interaction with organic and inorganic pollutants arouses concern for the...     

Vitellogenesis in the deep-sea shark Centroscymnus coelolepis

At present, information on the reproductive physiology of Centroscymnus coelolepis, which is one of most important and widespread deep-sea shark species, is completely lacking. In this study, we investigated vitellogenesis, a key step in the reproduction biology of fishes. Specimens of C. coelolepis were collected at 2850 m depth in the Western Mediterranean Sea. The size of the collected sharks (range: 35.5–65.0 cm TL) was much lower than those typically reported for the Atlantic and Pacific Oceans. The marked distinctiveness of Mediterranean and Atlantic/Pacific populations was reflected by the achievement of sexual maturity at a smaller size in Mediterranean specimens. The examination of cytoplasmatic components of oocytes indicated that vitellogenin uptake in the ovary started when oocytes reached 14 mm in diameter. Only reproductive females displayed a significant relationship between plasmatic vitellogenin and gonadal development, suggesting that vitellogenesis in C. coelolepis is a discontinuous process. Oestradiol levels were tightly coupled with gonadal development, underlining the importance of this hormone in controlling vitellogenesis. All these findings suggest that vitellogenesis in this yolk-sac viviparous shark might occur with similar mechanisms of oviparous vertebrates.     

Non-invasive prenatal testing (NIPT): Combination of copy number variant and gene analyses using an “in-house” target enrichment next generation sequencing—Solution for non-centralized NIPT laboratory?

Objective

Recent studies have integrated copy number variant (CNV) and gene analysis using target enrichment. Here, we transferred this concept to our routine genetics laboratory, which is not linked to centralized non-invasive prenatal testing (NIPT) facilities.

Method

From a cohort of 100 pregnant women, 22 were selected for the analysis of maternal genomic DNA (gDNA) along with fetal cell-free DNA. Using targeted enrichment, 135 genes were analyzed, combined with aberrations of chromosomes 21, 18, 13, X, and Y. The data were subjected to specificity and sensitivity analyses, and correlated with the results from invasive testing methods.

Results

The sensitivity/specificity was determined for the CNV analysis of chromosomes: 21 (80%/75%), 18 (-/82%), 13 (100%/67%), and Y (100%/100%). The gene detection was valid for maternal gDNA. However, for cell-free fetal DNA, it was not possible to determine the boundary between an artifact and a real sequence variant.

Conclusion

The target enrichment method combining CNV and gene detection seems feasible in a regular laboratory. However, this method can only be responsibly optimized with a sufficient number of controls and further validation on a strong bioinformatic background. The present results showed that NIPT should be performed in specialized centers, and that its introduction to isolated laboratories may not provide valid data.     

Microbial and kinetic characterization of pure and mixed cultures aerobically degrading 4-nitrophenol

The molecular and kinetic characterization of a microorganism able to aerobically degrade 4-nitrophenol (4NP) is presented. The microorganism was isolated from a mixed culture operating in a laboratory-scale sequencing batch reactor with an aerobic anoxic cycle. It was identified as a member of Ralstonia genus within Betaproteobacteria. It is a gram negative coccobacillum (cell length of 2-3 microm) able to aerobically store lipid inclusions when grown aerobically on nitrophenol as the sole carbon source in the range of tested concentrations (80-320 mg l(-1)). Batch kinetic tests were performed with the pure culture, while the kinetics of the mixed biomass was directly investigated in the reactor. For pure cultures exponential growth was observed, with growth rate values in the range of 2-6 d(-1); in experiments with the mixed cultures 4NP concentrations were correlated with growth using the Haldane equation (k(max) = 0.30 mg 4NP mg(-1) VSSh(-1); K(s) = 55 mg 4NPl(-1) and K(I) = 15 mg 4NPl(-1)). Observed pure culture growth rates were higher than those of mixed cultures. This result can be explained by considering that in mixed culture the biomass is evaluated as volatile suspended solids, including both specialized biomass for 4NP removal and denitrifying bacteria.