Development of unconventional biocatalytic strategies for the synthesis of sulfoxides

The synthesis of sulfoxides represents an ongoing challenge for the scientific community as these molecules find many applications in chemistry, varying from organic synthesis to medicinal chemistry. With the aim of providing a solution to the toxic and hazardous methods classically used for the synthesis of sulfoxides, biocatalysis has emerged in the past several decades as an alternative green and sustainable strategy to obtain both racemic and enantiopure sulfoxides. However, the use of enzymes still has some drawbacks, especially in terms of industrial applicability, as they often work on laboratory scale only, may lead to the production of other oxidative side products, or require the use of expensive cofactors and effective oxygenation. In this thesis, three different biocatalytic approaches for the synthesis of sulfoxides applicable in both academic and industrial settings are illustrated. First, the immobilised enzyme Candida antarctica lipase B was exploited to develop a mild, chemoselective and sustainable biocatalytic method, suitable for industrial use, for the preparation of sulfoxides from sulfides. Second, Baeyer-Villiger and flavine monooxygenases were investigated for the production of enantiopure sulfoxides that display multiple functional groups. Lastly, the reductive enzyme methionine sulfoxide reductase A (MsrA) from Saccharomyces cerevisiae was employed for the kinetic resolution of racemic sulfoxides using the inexpensive recycling co-substrate dithiothreitol and a total of 23 (R)-sulfoxides were obtained with excellent enantiomeric excess and yields. Additionally, the catalytic mechanism of the enzyme was investigated in depth via structural biology, mutagenesis, and in silico studies, which also led to the development of a new engineered MsrA biocatalyst capable of reducing bulky substrates

Effects of aqueous-supplementing artificial tears in wearers of biweekly replacement contact lenses vs wearers of daily disposable contact lenses

Purpose: To compare the effects of artificial tears (ATs) in wearers of biweekly replacement silicone hydrogel contact lenses (BW-Ws) and wearers of daily disposable contact lenses (DD-Ws) of the same material. Materials and Methods: The aqueous-supplementing ATs, OPTOyalA and OPTOidro, were assigned to be used for 2 weeks to healthy and young subjects: 1) 20 (8 and 12, respectively) BW-Ws wearing silicone hydrogel somofilcon A CLs (Clariti Elite), 2) 18 (9 and 9, respectively) DD-Ws wearing silicone hydrogel somofilcon A CLs (Clarity 1 Day), and 3) a control group of 33 (16 and 17, respectively) N-Ws. Ocular symptoms and comfort, tear volume and stability, and ocular surface condition were assessed by Ocular Surface Disease Index (OSDI), 5-Item Dry Eye Questionnaire (DEQ5), tear meniscus height (TMH), non-invasive tear break-up time (NIBUT), and evaluation of ocular redness (OR). The assessment was performed before and after 15 days of use of the ATs in the 3 groups (BW-Ws, DD-Ws, and N-Ws). Results: No clear significant difference was noted in symptoms and signs between OPTOyalA and OPTOidro irrespectively of the group of people studied. ATs use for 15 days produced a significant improvement in DEQ5 and OR in DD-Ws (Δ=-34%, p=0.006; Δ=-23%, p<0.001) and in N-Ws (Δ=-21%, p=0.001; Δ=-10%, p=0.006) but not in BW-Ws (Δ=-5%, p=0.072; Δ=-2%, p=0.257). No significant change was noted for TMH. Conclusion: In young and healthy subjects, the aqueous-supplementing effect of the ATs under consideration is more a rinsing and tear replacem ent effect than an increase in tear volume, and it produces an improvement of the eye redness and ocular symptoms. Contact lens wear influenced the effectiveness of ATs in a way which is correlated with the CL replacement schedule

Superspace approach to anomalous dimensions in {\cal N}=4 SYM

In a {\cal N}=1 superspace setup and using dimensional regularization, we give a general and simple prescription to compute anomalous dimensions of composite operators in {\cal N}=4, SU(N) supersymmetric Yang-Mills theory, perturbatively in the coupling constant g. We show in general that anomalous dimensions are responsible for the appearance of higher order poles in the perturbative expansion of the two-point function and that their lowest contribution can be read directly from the coefficient of the 1/\epsilon^2 pole. As a check of our procedure we rederive the anomalous dimension of the Konishi superfield at order g^2. We then apply this procedure to the case of the double trace, dimension 4, superfield in the 20 of SU(4) recently considered in the literature. We find that its anomalous dimension vanishes for all N in agreement with previous results.Comment: 23 pages, 8 figures; v2: conclusions about O_20 are change

Synthesis, Structural Elucidation, and Biological Evaluation of NSC12, an Orally Available Fibroblast Growth Factor (FGF) Ligand Trap for the Treatment of FGF-Dependent Lung Tumors

NSC12 is an orally available pan-FGF trap able to inhibit FGF2/FGFR interaction and endowed with promising antitumor activity. It was identified by virtual screening from a NCI small molecule library, but no data were available about its synthesis, stereochemistry, and physicochemical properties. We report here a synthetic route that allowed us to characterize and unambiguously identify the structure of the active compound by a combination of NMR spectroscopy and in silico conformational analysis. The synthetic protocol allowed us to sustain experiments aimed at assessing its therapeutic potential for the treatment of FGF-dependent lung cancers. A crucial step in the synthesis generated a couple of diastereoisomers, with only one able to act as a FGF trap molecule and to inhibit FGF-dependent receptor activation, cell proliferation, and tumor growth when tested in vitro and in vivo on murine and human lung cancer cells

KRAS Codons 12 and 13 Mutation Analysis: A Comparative Study between Direct Sequencing and a New Sensitive Real-Time PCR Assay

KRAS somatic mutations are found in 30–40% of colorectal cancer (CRC). Seven mutations in codons 12 and 13 of KRAS (95% of the observed human mutations) preclude the efficacy of anti-EGFR therapy for the treatment of CRC. Assessment of KRAS mutational status has become a standard procedure in the management of patients with CRC. Technically, KRAS mutation testing can be performed with different methods, characterized by distinct sensitivities and specificities. The present study analyzed KRAS in 182 CRC histological samples by using direct sequencing and a new kit based on a Real-Time Sequence-Specific Primers-PCR technology. The kit allowed to recover as positive 17 samples that were negative or unclear by sequencing, with a recovery rate equal to 13.82%. This study proposes a fast, sensitive, and high-throughput system to identify such seven described mutations of KRAS gene in CRC samples

Multiscale integration of satellite, airborne and field data for Mediterranean vegetation studies in the natural area of the Castelporziano Estate (Rome)

A new experimental approach to land analysis has recently been developed, based on the integration of information acquired on different scales; it enables the structure and the functionality of the vegetation in natural ecosystems to be analysed. This research aims at assessing the potentiality of the experimental approach by the integration of airborne and satellite remotely sensed data with ground measurements of structural parameters. In July 1999 a joint campaign for the acquisition of airborne (MIVIS, spatial resolution 3 in) and satellite remotely sensed data (Landsat 5TM, spatial resolution 30 in) and measures taken at ground (PAI), was deployed in the Presidential Estate at Castelporziano (Rome, Italy). The spectral signatures of the main vegetational types of the Estate were examined and the PAI were related to NDVI values, calculated by means of satellite and airborne images. The adopted approach enabled PAI maps to be produced. The linear relation between measured PAI and estimated PAI showed a higher coefficient of determination when the MIVIS data were used. The sensor high spectral resolution has moreover allowed to better describe the structural characteristics of the main plant typologies at Castelporziano Estate