Bacterial laccases: some recent advances and applications

Laccases belong to the large family of multi-copper oxidases (MCOs) that couple the one-electron oxidation of substrates with the four-electron reduction of molecular oxygen to water. Because of their high relative non-specific oxidation capacity particularly on phenols and aromatic amines as well as the lack of requirement for expensive organic cofactors, they have found application in a large number of biotechnological fields. The vast majority of studies and applications were performed using fungal laccases, but bacterial laccases show interesting properties such as optimal temperature above 50 °C, optimal pH at the neutral to alkaline range, thermal and chemical stability and increased salt tolerance. Additionally, bacterial systems benefit from a wide range of molecular biology tools that facilitates their engineering and achievement of high yields of protein production and set-up of cost-effective bioprocesses. In this review we will provide up-to-date information on the distribution and putative physiological role of bacterial laccases and highlight their distinctive structural and biochemical properties, discuss the key role of copper in the biochemical properties, discuss thermostability determinants and, finally, review biotechnological applications with a focus on catalytic mechanisms on phenolics and aromatic amines.info:eu-repo/semantics/publishedVersio

Raoultella ornithinolytica Isolation in Cloacal Microbiota of Tinamus solitarius: Preliminary Data

ABSTRACT Raoultella ornithinolytica is a gram-negative aerobic bacterium belonging to Enterobacteriaceae family, an emerging pathogen that causes several pathogenic conditions in man, with little veterinary importance; however, its identification is underestimated by conventional laboratory techniques. The present study reports the identification of R. ornithinolytica in Tinamus solitaries, during a routine sanitary evaluation of aerobic enterobacteria in cloacal microbiota of birds belonging to the Güira Oga Center, Puerto Iguazu, Argentina. The sample was preliminary classified as Klebsiella spp.; however, after the use of the MALDI-TOF MS technique it was identified as R. ornithinolytica. The sample was submitted to an antimicrobial susceptibility test, where it showed a similar pattern profile as reported in the literature, with resistance to ampicillin and other β-lactam antibiotics. It is possible that Raoultella spp are more common in birds as it is reported. Therefore, review studies on bacteria collections of avian origin, as well as cases with confirmation of Klebsiella, should be deeply evaluated in laboratorial routine, mainly due to the pathogenic potential of R. ornithinolytica for Poultry, as well as for public health

Functionally Null <i>RAD51D</i> Missense Mutation Associates Strongly with Ovarian Carcinoma.

RAD51D is a key player in DNA repair by homologous recombination (HR), and RAD51D truncating variant carriers have an increased risk for ovarian cancer. However, the contribution of nontruncating RAD51D variants to cancer predisposition remains uncertain. Using deep sequencing and case-control genotyping studies, we show that in French Canadians, the missense RAD51D variant c.620C>T;p.S207L is highly prevalent and is associated with a significantly increased risk for ovarian high-grade serous carcinoma (HGSC; 3.8% cases vs. 0.2% controls). The frequency of the p.S207L variant did not significantly differ from that of controls in breast, endometrial, pancreas, or colorectal adenocarcinomas. Functionally, we show that this mutation impairs HR by disrupting the RAD51D-XRCC2 interaction and confers PARP inhibitor sensitivity. These results highlight the importance of a functional RAD51D-XRCC2 interaction to promote HR and prevent the development of HGSC. This study identifies c.620C>T;p.S207L as the first bona fide pathogenic RAD51D missense cancer susceptibility allele and supports the use of targeted PARP-inhibitor therapies in ovarian cancer patients carrying deleterious missense RAD51D variants. Cancer Res; 77(16); 4517-29. ©2017 AACR