A biocatalytic approach has been designed for the synthesis of optically active piperazinones and 1,4‐diazepanones in aqueous medium under mild conditions. The method described herein is based on a ...biocatalytic transamination of an easily accessible N‐(2‐oxopropyl) amino acid ester and the subsequent spontaneous cyclization of the initially formed amine. Both enantiomers of the synthesized piperazinones can be prepared by the selection of amine transaminases of opposite selectivity. The reaction conditions were optimised and eight selected processes were performed on a preparative scale. Thus, seven optically active piperazinones were synthesized in high isolated yields (70–90%) and a 1,4‐diazepanone in a moderate yield (51%), being the ee ≥99% in all the cases.
•Advanced selective synthesis of CLA rich phosphatidylcholines.•Selective acydolysis of phospholipids with new immobilized Lecitase Ultra.•Rapid, selective and high yield production of structured ...phospholipids.•New immobilized phospholipase A1 speeds up phosphatidylcholine acidolysis with CLA.•Overcoming structured phospholipid synthesis drawbacks: hydrolysis/selectivity/speed.
Phospholipids (PL) rich in conjugated linolenic acid (CLA) have important health effects. Yields of phosphatidylcholine (PC) acidolysis with CLA use to be limited to <30%, due to competitive side-hydrolysis. Duolite A658–Lecitase is a very suitable biocatalyst for this reaction.
In this study, PC hydrolysis has been practically eliminated using extremely dried lyophilized PC (279 ± 4 mg water/Kg PC), obtaining close to 100% molar yield of modified PC (72.3% CLA) with Duolite-Lecitase in 24 h, the highest yield reported in the literature for this reaction. It has been better improved by changing the immobilization support, using three food grade hydrophobic supports (Styrene, and two Octadecyl methacrylates (OM and OMC)). In only 2 h, with a 1/12 PC/CLA molar ratio at 50 °C, similar almost quantitative yields of PC with 74.4% CLA content has been obtained using OM-Lecitase. The fatty acid composition of modified PCs is not affected by the enzyme immobilization protocol.
In this book, 15 papers, covering some of the latest advances in pretreatment and bioconversion of crop residues, are presented. Research results dealing with wheat straw, corn stover, sweet sorghum ...bagasse, hazelnut shells, oil palm empty fruit bunch, olive tree pruning biomass, and other residues of crop harvest and processing are discussed. Pretreatment methods, such as auto-catalyzed and acid-catalyzed hydrothermal processing, steaming, alkaline methods, and different organosolv approaches, are reported. Bioconversion with enzymes and microbes for producing fermentable sugars, xylitol, and biomethane are also included.
Collision with electric power lines is a conservation problem for many bird species. Although the implementation of flight diverters is rapidly increasing, few well-designed studies supporting the ...effectiveness of this costly conservation measure have been published.
We provide information on the largest worldwide marking experiment to date, including carcass searches at 35 (15 experimental, 20 control) power lines totalling 72.5 km, at both transmission (220 kV) and distribution (15 kV-45 kV) lines. We found carcasses of 45 species, 19 of conservation concern. Numbers of carcasses found were corrected to account for carcass losses due to removal by scavengers or being overlooked by researchers, resulting in an estimated collision rate of 8.2 collisions per km per month. We observed a small (9.6%) but significant decrease in the number of casualties after line marking compared to before line marking in experimental lines. This was not observed in control lines. We found no influence of either marker size (large vs. small spirals, sample of distribution lines only) or power line type (transmission vs. distribution, sample of large spirals only) on the collision rate when we analyzed all species together. However, great bustard mortality was slightly lower when lines were marked with large spirals and in transmission lines after marking.
Our results confirm the overall effectiveness of wire marking as a way to reduce, but not eliminate, bird collisions with power lines. If raw field data are not corrected by carcass losses due to scavengers and missed observations, findings may be biased. The high cost of this conservation measure suggests a need for more studies to improve its application, including wire marking with non-visual devices. Our findings suggest that different species may respond differently to marking, implying that species-specific patterns should be explored, at least for species of conservation concern.
Objective Laryngopharyngeal reflux (LPR) is a common illness of otolaryngology visits. Over the past few years, pepsin has become a promising marker of LPR. The objective of the present research is ...to analyze the existing literature using pepsin as a diagnostic tool of LPR through a systematic review. Data Sources PubMed (Medline), Trip Database, Cochrane Library, EMBASE, SUMsearch, and Web of Science. Review Methods The outcome assessed was the presence of pepsin in LPR patients. We included articles in which pepsin was studied in LPR patients (clinically suspected or with confirmed diagnosis). Studies with no control group, comparison group, and/or a sample size lower than 20 patients were excluded. Results Twelve studies were included. All included studies, with the exception of 2, found statistically significant differences for pepsin in cases compared with healthy controls. Conclusion Pepsin might be a reliable marker in LPR patients, although questions remain about optimal timing, location, nature, and threshold values for pepsin testing. Future investigations are necessary to clarify the best method to use pepsin in the diagnostic process of LPR.
•Lipase immobilization via interfacial activation.•Improved selective synthesis of partial glycerides of CLA.•Modulation of lipases regioselectivity via immobilization.
Lipases B from Candida ...antarctica (CALB), Rhizomucor miehei (RML) and Thermomyces lanuginosus (TLL) were immobilized on octadecyl methacylate (OM) or octadecyl methacrylate (OMC) beads. Their specific activity and regioselectivity were studied in the synthesis of conjugated linoleic acid (CLA) partial glycerides, which presented nutraceutical properties.
TLL derivatives were poor catalysts. Novozym® 435 was much better than Lipozyme® RM IM. RML activity (a GRAS enzyme) was modulated via immobilization. After only 3 h, OM−RML gave the highest CLA conversion (54% at 40 °C with 1:3 M ratio of glycerol to CLA). OM-RML reduced by a factor of 3.12 and 1.16 the activation energy of the reaction with Lipozyme® RM IM and Novozym® 435, respectively.
The new GRAS preparation OM-RML brings forth an optimal regioselective preparation of sn-1 mono and sn-1,3 diacylglycerols rich in CLA, with a ratio of sn-1,3/sn-1,2 regioisomers of 21.8, compared to 2.3 for Novozym® 435.
•Improbed performance of Acidolisis of phosphatidyl choline.•Enhanced method of synthesis of CLA rich phospholids.•Acidolysis of phosphatidyl choline with Lecitase Ultra.•Synthesis of phospholipids ...rich in conjugated linoleic acid.
Conjugated linolenic acid (CLA) has important health effects, and their phospholipids forms (PL) are advantageous vehicles of this bioactive agent. Acidolysis of soybean phosphatidylcholine (PC) with conjugated linolenic acid (CLA) catalyzed by Lecitase® Ultra immobilized on Duolite A658 was studied. This reaction is typically limited by hydrolysis, producing 60–90 % of lyso- and glycero-PC and yielding low the process efficiency. Drying the amphiphilic PC material was found the key factor for maximal diacylglycerol phosphatidylcholines (PC) production and different drying approaches were studied to maximize the formation of PC rich in CLA in a solvent free process.
PC lyophilization for 24 h getting dry solid appearance (PC; 783 ± 11 mg water/Kg PC) or other standard protocols to reduce water content/activity of reaction medium, did not improve the reaction performance. However, adding 4 extra days to the second step of lyophilization at high vacuum (1 Pa) and moderate temperature (20 °C), followed by further PC dehydration with molecular sieves, drastically reduced the hydrolysis process by achieving a extensive PC dehydration (279 ± 4 mg water/Kg PC), obtaining for the first time >99% molar yield of diacyl-PC product. After 24 h of reaction, a diacyl-PC product with 72.3% CLA content was obtained. PC molecules containing two CLA were the major species formed.
biomass is a sustainable source of bioactive products for the food, cosmetic, and medicine industries. As well as primary metabolites, different secondary metabolites can be obtained via distinct ...enzymatic degradation of biomass. In this work, different hydrophilic extracts were obtained after treating the biomass with: (i) a serine
-peptidase (Alcalase
), (ii) a mixture of amino-, dipeptidyl-, and
-peptidases (Flavourzyme
), (iii) a mixture of
-1,3(4)-β-glucanase and an
-1,4-xylanase, and β-glucanase (Ultraflo
), and (iv) an
-1,3-glucanase (Vinoflow
) (all the enzymes from Novozymes A/S (bagsvaerd, Denmark)); with subsequent extraction of the biocomponents with an isopropanol/hexane mixture. The composition of each aqueous phase extract (in terms of amino acids, peptides, oligo-elements, carbohydrates, and phenols) and their in vitro functional properties were compared. The conditions described in this work using the enzyme Alcalase
permits the extraction of eight distinctive peptides. This extract is 7.3 times more anti-hypertensive, 106 times more anti-hypertriglyceridemic, 26 times more hypocholesterolemic, has 4.4 times more antioxidant activities, and has 2.3 times more phenols, than the extract obtained without any prior enzyme biomass digestion. Alcalase
extract is an advantageous product with potential application in functional food, pharmaceutics, and cosmetics.
•Periodontal pathogens studied showed complete susceptibility to moxifloxacin.•Isolates had reduced susceptibility to amoxicillin, azithromycin and metronidazole.•Moxifloxacin is a favourable option ...against periodontal pathogens.
Administration of systemic antimicrobials as an adjunct to mechanical treatment of periodontitis and sites with adverse clinical results leads to improved outcomes. This study aimed to assess the antimicrobial susceptibility of Aggregatibacter actinomycetemcomitans, Porphyromonas gingivalis and Tannerella forsythia isolated from periodontitis patients to amoxicillin, metronidazole, azithromycin and moxifloxacin.
A total of 76 patients diagnosed with generalised periodontitis were included in the study. Subgingival samples were processed by culture. Etest was used to determine susceptibility to amoxicillin, metronidazole, azithromycin and moxifloxacin.
A total of 141 isolates from 76 patients were evaluated, including 61 P. gingivalis, 43 T. forsythia and 37 A. actinomycetemcomitans. Etest results showed complete susceptibility of A. actinomycetemcomitans, P. gingivalis and T. forsythia to moxifloxacin. However, the isolates presented reduced susceptibility to the other antimicrobial agents investigated. Of the A. actinomycetemcomitans isolates, 70.3%, 40.5% and 89.2% were resistant to amoxicillin, azithromycin and metronidazole, respectively. The P. gingivalis samples showed relatively similar rates of resistance to amoxicillin (24.6%), azithromycin (21.3%) and metronidazole (24.6%). Similarly, 25.6%, 21.0% and 25.6% of the T. forsythia isolates were resistant to amoxicillin, azithromycin, and metronidazole, respectively.
These findings show that moxifloxacin may be a promising antimicrobial agent against P. gingivalis, T. forsythia and A. actinomycetemcomitans for the treatment of periodontitis. However, amoxicillin, azithromycin and metronidazole were less effective, especially against A. actinomycetemcomitans in vitro.
To evaluate the accuracy of the macular retinal layer segmentation software of the Spectralis spectral-domain (SD) optical coherence tomography (OCT) device (Heidelberg Engineering, Inc., Heidelberg, ...Germany) to discriminate between healthy and early glaucoma (EG) eyes.
Prospective, cross-sectional study.
Forty EG eyes and 40 healthy controls were included.
All participants were examined using the standard posterior pole and the peripapillary retinal nerve fiber layer (pRNFL) protocols of the Spectralis OCT device. Using an Early Treatment Diagnostic Retinopathy Study circle at the macular level, the automated retinal segmentation software was applied to determine thicknesses of the following parameters: total retinal thickness, inner retinal layer (IRL), macular retinal nerve fiber layer (mRNFL), macular ganglion cell layer (mGCL), macular inner plexiform layer (mIPL), macular inner nuclear layer (mINL), macular outer plexiform layer (mOPL), macular outer nuclear layer (mONL), photoreceptors (PR), and retinal pigmentary epithelium (RPE). The ganglion cell complex (GCC) was determined by adding the mRNFL, mGCL, and mIPL parameters and the ganglion cell layer-inner plexiform layer (mGCL-IPL) was determined by combining the mGCL and mIPL parameters. Thickness of each layer was compared between the groups, and the layer and sector with the best area under the receiver operating characteristic curve (AUC) were identified.
Comparison of pRNFL, IRL, mRNFL, mGCL, mIPL, mGCC, mGCL-IPL, mINL, mOPL, mONL, PR, and RPE parameters and total retinal thicknesses between groups for the different areas and their corresponding AUCs.
Peripapillary RNFL was significantly thinner in the EG group globally and in all 6 sectors assessed (P < 0.0005). For the macular variables, retinal thickness was significantly reduced in the EG group for total retinal thickness, mIRL, mRNFL, mGCL, and mIPL. The 2 best isolated parameters to discriminate between the 2 groups were pRNFL (AUC, 0.956) and mRNFL (AUC, 0.906). When mRNFL, mGCL, and mIPL measurements were combined (mGCC and mGCL plus mIPL), then its diagnostic performance improved (AUC, 0.940 and 0.952, respectively).
Macular RNFL, mGCL-IPL, and mGCC measurements showed a high diagnostic capability to discriminate between healthy and EG participants. However, macular intraretinal measurements still have not overcome standard pRNFL parameters.
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