530 research outputs found
Effects of Probiotics on Zebrafish Reproduction
No full textRecent studies have demonstrated that probiotics can infuence reproductive performance, however, the mechanisms infuencing oogenesis remain poorly explored. In this study, the effects of dietary probiotic Lactobacillus rhamnosus IMC 501® administration was investigated on female zebrafish (D. rerio) reproductive performance and ovarian development (both growth and maturation phases). After feeding the zebrafish experimental diets for 10 days, real-time PCR and culture based methods revealed alterations on gut microbiota, characterised by high levels of L. rhamnosus IMC 501® in the gut of probiotic treated zebrafish, which were absent in the control. The microbial modulation in the gut was related with a signifcant increase of the gonadosomatic-index (GSI) associated, at the molecular level, to a signifcant increase of ovarian expression of cytochrome p 19 (cyp19a), hepatic vitellogenin (vtg) and the α isoform of the estradiol receptor (erα) genes evidencing a positive role of probiotic administration on the ovarian growth phase. Concomitantly, a signifcant increase of signals which positively control the maturation phase such as, cyclin B, activinβA1 and small mother against decapentaplegic 2 (smad2) genes in the ovary led us to confirm the beneficial role of the probiotic on maturation processes. Next to the enhancement of oocyte development processes by probiotic administration, an improvement of fecundity was evidenced which was associated with the increase of cyclooxygenase 2a (co×2a) gene expression in the ovary. The significance of the results obtained herein underlines the importance of diet and gut microbes in the reproductive processes, supporting the hypothesis that feed additives could improve fecundit
An alternative mechanism of clathrin-coated pit closure revealed by ion conductance microscopy
Get PDFCurrent knowledge of the structural changes taking place during clathrin-mediated endocytosis is largely based on electron microscopy images of fixed preparations and x-ray crystallography data of purified proteins. In this paper, we describe a study of clathrin-coated pit dynamics in living cells using ion conductance microscopy to directly image the changes in pit shape, combined with simultaneous confocal microscopy to follow molecule-specific fluorescence. We find that 70% of pits closed with the formation of a protrusion that grew on one side of the pit, covered the entire pit, and then disappeared together with pit-associated clathrin-enhanced green fluorescent protein (EGFP) and actin-binding protein-EGFP (Abp1-EGFP) fluorescence. This was in contrast to conventionally closing pits that closed and cleaved from flat membrane sheets and lacked accompanying Abp1-EGFP fluorescence. Scission of both types of pits was found to be dynamin-2 dependent. This technique now enables direct spatial and temporal correlation between functional molecule-specific fluorescence and structural information to follow key biological processes at cell surfaces
Effect of dietary alginic acid on juvenile tilapia (Oreochromis niloticus) intestinal microbial balance, intestinal histology and growth performance.
No full text1,3 proton transfer catalysts supported by Merrifield resin or Jeffamine gel
No full text6-Chloronicotinic acid was coupled by an amide linkage to Merrifield resin or Jeffamine gel. Nucleophilic displacement of the 6-chloride group by hydroxide gave novel Merrifield resin catalyst 6 or Jeffamine gel catalyst 9 that were successfully used for Henry condensations. The condensation of 4,6-O-benzylidene-β-D-glucopyranose 11 with nitromethane gave 4,6-O-benzylidene-D-glucopyranosyl-l-nitromethane 12; the condensation of 11 with nitroethane gave α-R-(4,6-O-benzylidene-β-D-glucopyranosyl)-1-nitroethane 13 and its diastereomer 15; the condensation of 11 with nitropropane, followed by acetylation, gave α-R-(2,3-di-O-acetyl-4,6-O-benzylidene-β- D-glucopyranosyl)-1 -nitropropane 16 and its diastereomer 17; the condensation of 4,6- O-isopropylidene-β-D-glucopyranose 19 with nitromethane gave 4,6-O-isopropylidene- β-D-glucopyranosyl-1-nitromethane 20; the condensation of 4,6-O-isopropylidene-α- D-mannopyranose 21 with nitromethane gave 4,6-O-isopropylidene-β-D-mannopyranosyl- 1-nitromethane 23. These known compounds were obtained with improved yields compared to protocols with 1,3 proton transfer catalysts that were not bound to polymers. A new monomeric 1,3 proton transfer catalyst, 2,4 (1,3)-quinazolinedione 10, was also introduced
Dietary modulation of immune response and related gene expression profiles in mirror carp (Cyprinus carpio) using selected exotic feed ingredients
No full textMicrobial manipulations to improve fish health and production--a Mediterranean perspective.
No full textVERSATILE FMOC-ACETAL MERRIFIELD RESINS: SYNTHESES OF BICYCLIC LACTAMS & LACTONES
No full textposter abstractThe preparation of Merrifield resins 5, which represent versatile intermediates
in the syntheses of lactones, lactams, and bicyclic, tricyclic, and
tetracyclic scaffolds, is described. The presence of Fmoc and acetal
protecting groups allows for the eventual incorporation of ozone-labile
groups at R2 (as in III) such as alkenes, alkynes, electron-rich aromatics
and pi-excessive heterocycles whereas the previously reported route can
only accommodate ozone-compatible groups.
An extension of the current methodology to include bicyclic lactams,
which features elaboration at each of R1, R2, and R3 of III including
fragment condensation examples 10a-c, is described. In all cases
separation and characterization of two of the four possible diastereomers
was achieved. Using 2-D NMR methods the relative configuration of the two
diastereomers is being established. Structures such as III are of interest
since the thiazabicycloalkane ring system is a known bioactive scaffold that
mimics the beta-turn (reverse turn) in polypeptides and proteins
VERSATILE FMOC-ACETAL MERRIFIELD RESINS: SYNTHESES OF BICYCLIC LACTAMS & LACTONES
No full textposter abstractThe preparation of Merrifield resins 5, which represent versatile intermediates
in the syntheses of lactones, lactams, and bicyclic, tricyclic, and
tetracyclic scaffolds, is described. The presence of Fmoc and acetal
protecting groups allows for the eventual incorporation of ozone-labile
groups at R2 (as in III) such as alkenes, alkynes, electron-rich aromatics
and pi-excessive heterocycles whereas the previously reported route can
only accommodate ozone-compatible groups.
An extension of the current methodology to include bicyclic lactams,
which features elaboration at each of R1, R2, and R3 of III including
fragment condensation examples 10a-c, is described. In all cases
separation and characterization of two of the four possible diastereomers
was achieved. Using 2-D NMR methods the relative configuration of the two
diastereomers is being established. Structures such as III are of interest
since the thiazabicycloalkane ring system is a known bioactive scaffold that
mimics the beta-turn (reverse turn) in polypeptides and proteins
Synthesis of the small peptide analogues of cyclin dependent kinase (CDK4) for cancer treatment
No full textCyclin-dependent kinases (CDKs) are a group of enzymes that are involved in cell cycle progression regulation. The CDKs activate host proteins through phosphorylation on serine or threonine using adenosine triphosphate as a phosphate donor. Especially, cyclindependent kinase 4 (CDK4) has attracted much attention as a potential therapeutic target in treating cancer because it is the key player in the control of cell proliferation. Comparison of the best model of CDK4 with the structures of CDK6 and CDK2 is shown difference in the cyclin-binding region and in overall electrostatic potential. A partially hydrophobic, externalized loop structure present in CDK4, but absent in CDK2 and CDK6 is identified. The hypothesis is that should CDK4 be involved in binding to an additional unidentified protein partner, this fragment provides the most likely candidate for the binding site. This has led to the discovery of a peptide 1, N-Ac-L-Pro-L-Arg(H)-Gly-L-Pro-L-Arg(H)-L-Pro- NH2, from a previously uncharacterized structural domain on CDK4. In this work, solution phase peptide synthetic method is optimized and developed to synthesize linear peptide 64, N-Boc-L-Pro-L-Arg(NO2)-Gly-L-Pro-L-Arg(NO2)-L-Pro-OMe. A series of side chain modification peptides of compound 64 was synthesized and found that peptide 71, N-Ac-LPro- L-Arg(NO2)-Gly-L-Pro-L-Arg(NO2)-L-Pro-OMe had the most potent for anticancer activity. Therefore, alanine scanning compounds of hexapeptide 71 were synthesized by replacing each amino acid residue with L-alanine to investigate which amino acid residue had shown anticancer activity. Solid phase method was also optimized to synthesized peptide 1 and its alanine scanning compounds. To improve anticancer activity, cyclic peptides are synthesized by solution phase method. Biological assays were optimized. Clonogenic assay was chosen to test with our synthetic peptides against RT112 bladder cancer and MRC5-hTERT fibroblast cell
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