Fatty Acid Composition and Cytotoxic Activity of Lipid Extracts from Nannochloropsis gaditana Produced by Green Technologies

Microalgae are alternatives and sustainable sources of omega-3 long chain-polyunsaturated fatty acids (LC-PUFA). However, the eco-friendly extraction of these bioactives remains unexplored. In this work, the use of enzyme-based methods in combination with ultrasounds was evaluated as green approaches to extract the omega-3 lipids from Nannochloropsis gaditana. Three commercial enzymatic solutions (Viscozyme^® L, Celluclast^® 1.5 L, and Saczyme^®) were investigated, and results were compared with the traditional Folch method. A promising extraction approach was developed by using Saczyme^®, achieving a lipid yield of 25.7% ± 0.5, comparable to the traditional method (27.3% ± 0.7) (p > 0.05). Similar omega-3 content was found by GC–MS analysis for both lipid extracts (30.2% ± 2.4 and 29.3% ± 0.8 for the green and the traditional method, respectively), showing that the green approaches did not affect the fatty acid profile. Moreover, the cytotoxic activity of produced lipids was assessed by comparing human colon cancer cells (HCT-116) and epithelial nontumorigenic immortalized cells (HCEC-1CT). Results suggest that the lipid extracts have a selective effect, reducing the viability of the colon carcinoma cells but not the nontumorigenic cells. Thus, this study provides new eco-innovative approaches for extracting the omega-3 LC-PUFA from microalgae with promising biological properties.     

A Screening Protocol for Exploring Loop Length Requirements for the Formation of a Three Cytosine-Cytosine+ Base-Paired i-Motif

DNA sequences containing at least four runs of repetitive cytosines can fold into tetra-helical structures called i-Motifs (iMs). The interest in these DNA secondary structures is increasing due to their therapeutical and technological applications. Still, limited knowledge of their folding requirements is currently available. We developed a novel step-by-step pipeline for the systematic screening of putative iM-forming model sequences. Focusing on structures comprising only three cytosine-cytosine⁺ base pairs, we investigated what the minimal lengths of the loops required for formation of an intra-molecular iM are. Our data indicate that two and three nucleotides are required to connect the strands through the minor and majorgrooves of the iM, respectively. Additionally, they highlight an asymmetric behavior according to the distribution of the cytosines. Specifically, no sequence containing a single cytosine in the first and third run was able to fold into intra-molecular iMs with the same stability of those formed when the first and the third run comprise two cytosines. This knowledge represents a step forward toward the development of prediction tools for the proper identification of biologically functional iMs, as well as for the rational design of these secondary structures as technological devices.     

Investigating Possible Dipole-Bound States of Cyanopolyynes: the Case for the C5N− Anion Detected in Interstellar Space

We present results of quantum structure calculations aimed at demonstrating the possible existence of dipole-bound states (DBS) for the anion , a species already detected in the Interstellar medium (ISM). The positive demonstration of DBS existence using ab initio studies is an important step toward elucidating possible pathways for the formation of the more tightly bound valence bound states (VBS) in environments where free electrons from starlight ionization processes are known to be available to interact with the radical partner of the title molecule. Our current calculations show that such excited DBS states can exist in , in agreement with what we had previously found for the smallercyanopolyyne in the series: the anion. This system has a very weakly bound anion with binding energies of about 3 and 9 cm⁻¹ for the and DBS, respectively.     

Rapid estimation of chemical kinetics by implicit calibration. II

This study continues the development of a method, implicit calibration, for estimating kinetic parameters from on-line measurements of batch reactions. The basic idea of implicit calibration is to combine non-linear parameter estimation with the calibration of measured spectra with concentrations calculated by an assumed kinetic model. A new example is studied, an esterification reaction with a rather complicated kinetic mechanism, where activities, instead of concentrations, and NIR spectra are used as measurements. The emphasis in the study is on estimating the uncertainty of the kinetic parameters. Two approaches, linearization and bootstrap, are applied. In the case studied, the two approaches give closely similar estimates of the uncertainty. As well, a new way is introduced to control the rigidity of the implicit calibration, based on minimizing the lack of fit of the model. It is also shown that ‘mixed implicit calibration’, i.e. implicit calibration combined with a few off-line calibrated concentrations, greatly enhances the identifiability of the kinetic model. Copyright © 2003 John Wiley & Sons, Ltd.     

Plus-Size DiPAMP Hybrids for Advanced Rhodium(I)-Catalyzed Hydrogenation: The 2RBigFUS Model

Outfitting the P,P′-distereogenic 2MeBigFUS ligand with the characteristic branched/functionalized-alkoxy feature of the R-SMS-Phos design furnished the 2RBigFUS family (Figure 2). Rhodium(I) complexes thereof exhibited a further boosted activity and superior enantioselectivity in the hydrogenation of various functionalized olefins, including the challenging α-arylacrylic acids. The application under practical conditions to enantiomeric active pharmaceutical ingredients (APIs) and relevant synthetic building blocks capped the outcome.