Aims: To investigate the petroleum hydrocarbon (HC)‐degrading potential of indigenous micro‐organisms in a sandy Mediterranean coast, accidentally contaminated with petroleum‐derived HCs.
Methods and Results: Using culturable methods, a population of Gram‐positive n‐alkane degraders was detected in the contaminated soil. Five isolates, identified as one Nocardia, two Rhodococcus and two Gordonia strains, were able to degrade medium‐ and long‐chain n‐alkanes up to C36 as assessed by growth assays and gas chromatography‐mass spectrometry analysis. Diverging alkane hydroxylase‐encoding genes (alkB) were detected by PCR, using degenerated primers, in all the strains; multiple sequences were obtained from the Nocardia strain, while only one alkB gene was detected in the Rhodococcus and Gordonia strains. The majority of the alkB sequences were related to Rhodococcus alkB2, but none was identical to it.
Conclusions: Actinomycetes might have a key role in bioremediation of n‐alkane‐contaminated sites under dry, resource‐limited conditions, such as those found in the Mediterranean shorelines.
Significance and Impact of the Study: To our knowledge, this is the first study on the bioremediation potential in Mediterranean contaminated beaches.
a Halloysite (HNT) is a promising natural nanosized tubular clay mineral that has many important uses in different industrial fields. It is naturally occurring, biocompatible, and available in thousands of tons at low cost. As a consequence of a hollow cavity, HNT is mainly used as nanocontainer for the controlled release of several chemicals. Chemical modification of both surfaces (inner lumen and outer surface) is a strategy to tune the nanotube's properties. Specifically, chemical modification of HNT surfaces generates a nanoarchitecture with targeted affinity through outer surface functionalization and drug transport ability from functionalization of the nanotube lumen. The primary focus of this review is the research of modified halloysite nanotubes and their applications in biological and medical fields.
A simple synthetic methodology for the preparation of a polystyrene-supported L-proline material is reported, and this material has been used as catalyst in direct asymmetric aldol reactions between several ketones and arylaldehydes to furnish aldol products in high yields and stereoselectivities. Screening of solvents showed that these reactions take place only in the presence of water or methanol, at lower levels of conversion in the latter case. This solvent effect, coupled with the observed high stereoselectivities, has been ex-
The interaction of native calf thymus DNA with the Zn(II) and Cu(II) complexes of 5-triethyl ammonium methyl salicylidene ortophenylendiimine (ZnL 2+ and CuL 2+ ), in 1 mM Tris-HCl aqueous solutions at neutral pH, has been monitored as a function of the metal complex-DNA molar ratio by UV absorption spectrophotometry, circular dichroism (CD) and fluorescence spectroscopy. The results support for an intercalative interaction of both ZnL 2+ and CuL 2+ with DNA, showing CuL 2+ an affinity of approximately 10 times higher than ZnL 2+ . In particular, the values of the binding constant, determined by UV spectrophotometric titration, equal to 7.3 · 10 4 and 1.3 · 10 6 M À1 , for ZnL 2+ and CuL 2+ , respectively, indicate the occurrence of a marked interaction with a binding size of about 0.7 in base pairs. The temperature dependence of the absorbance at 258 nm suggests that both complexes strongly increase the DNA melting temperature (Tm) already at metal complex-DNA molar ratios equal to 0.1. As evidenced by the quenching of the fluorescence of ethidium bromide-DNA solutions in the presence of increasing amounts of metal complex, ZnL 2+ and CuL 2+ are able to displace the ethidium cation intercalated into DNA. A tight ZnL 2+ -DNA and CuL 2+ -DNA binding has been also proven by the appearance, in both metal complex-DNA solutions, of a broad induced CD band in the range 350-450 nm. In the case of the CuL 2+ -DNA system, the shape of the CD spectrum, at high CuL 2+ content, is similar to that observed for w-DNA solutions. Such result allowed us to hypothesize that CuL 2+ induces the formation of supramolecular aggregates of DNA in aqueous solutions.
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