Convergent synthesis of (+)-carambolaflavone A, an antidiabetic agent using a bismuth triflate-catalyzed C-aryl glycosylation.

We describe a convergent total synthesis of carambolaflavone A, a natural flavonoid C-aryl glycoside with significant antihyperglycemic properties. The synthesis features a bismuth triflate-catalyzed stereoselective C-aryl glycosylation of a flavan derivative and an appropriately protected D-fucose derivative as the key step. Inexpensive and non-toxic bismuth triflate provided the best results among various other Lewis acids screened for this C-aryl glycosylation. The method can be utilized for the synthesis of other bioactive C-glycosyl flavonoids. The glycosylation partners were synthesized from commercially available (±)-naringenin and D-(+)-galactose, respectively. An oxidative bromination and elimination reaction sequence was utilized to construct the flavone. The natural product is obtained in 13 steps (longest linear sequence) from D-(+)-galactose.

Soluble Non-Starch Polysaccharides From Plantain (Musa x paradisiaca L.) Diminish Epithelial Impact of Clostridioides difficile.

Clostridioides difficile infection (CDI) is a leading cause of antibiotic-associated diarrhoea. Adhesion of this Gram-positive pathogen to the intestinal epithelium is a crucial step in CDI, with recurrence and relapse of disease dependent on epithelial interaction of its endospores. Close proximity, or adhesion of, hypervirulent strains to the intestinal mucosa are also likely to be necessary for the release of C. difficile toxins, which when internalized, result in intestinal epithelial cell rounding, damage, inflammation, loss of barrier function and diarrhoea. Interrupting these C. difficile-epithelium interactions could therefore represent a promising therapeutic strategy to prevent and treat CDI. Intake of dietary fibre is widely recognised as being beneficial for intestinal health, and we have previously shown that soluble non-starch polysaccharides (NSP) from plantain banana (Musa spp.), can block epithelial adhesion and invasion of a number of gut pathogens, such as E. coli and Salmonellae. Here, we assessed the action of plantain NSP, and a range of alternative soluble plant fibres, for inhibitory action on epithelial interactions of C. difficile clinical isolates, purified endospore preparations and toxins. We found that plantain NSP possessed ability to disrupt epithelial adhesion of C. difficile vegetative cells and spores, with inhibitory activity against C. difficile found within the acidic (pectin-rich) polysaccharide component, through interaction with the intestinal epithelium. Similar activity was found with NSP purified from broccoli and leek, although seen to be less potent than NSP from plantain. Whilst plantain NSP could not block the interaction and intracellular action of purified C. difficile toxins, it significantly diminished the epithelial impact of C. difficile, reducing both bacteria and toxin induced inflammation, activation of caspase 3/7 and cytotoxicity in human intestinal cell-line and murine intestinal organoid cultures. Dietary supplementation with soluble NSP from plantain may therefore confer a protective effect in CDI patients by preventing adhesion of C. difficile to the mucosa, i.e. a "contrabiotic" effect, and diminishing its epithelial impact. This suggests that plantain soluble dietary fibre may be a therapeutically effective nutritional product for use in the prevention or treatment of CDI and antibiotic-associated diarrhoea.

Human Acellular Dermal Matrix Is a Viable Alternative to Autologous Skin Graft in Patients with Cutaneous Malignancy.

Skin substitutes have shown success in complex wound reconstruction. We evaluate the use of a human acellular dermal matrix (ADM) as a viable alternative to autologous skin grafting for defects secondary to skin cancer excision. An institutional review board-approved, retrospective review of ADM-reconstructed defects secondary to skin cancer excision between 2012 and 2018 was conducted. ADM was indicated in patients with preclusive factors for general anesthesia, protracted procedure time, reluctance for additional donor site wound, and personal choice. We reviewed defect characteristics, healing time, postoperative outcomes, and patient demographics. The 228 participants (151 males, 77 females) had a median age of 72 years (range, 29-95 years), with melanoma diagnosed in 113 (49.6%), squamous cell carcinoma in 61 (26.8%), and basal cell carcinoma in 28 (12.2%) patients. The median interval to complete epidermal coverage was 42 days, with graft failure evident in six patients (2.6%). ADM is a viable, low-morbid alternative for reconstruction of defects secondary to skin cancer excision, with no donor site morbidity. With exception to complete healing time, outcomes are similar to those of autologous grafting.

Potent HIV-1 protease inhibitors incorporating squaramide-derived P2 ligands: Design, synthesis, and biological evaluation.

We describe the design, synthesis, and biological evaluation of novel HIV-1 protease inhibitors containing a squaramide-derived scaffold as the P2 ligand in combination with a (R)-hydroxyethylamine sulfonamide isostere. Inhibitor 3h with an N-methyl-3-(R)-aminotetrahydrofuranyl squaramide P2-ligand displayed an HIV-1 protease inhibitory Ki value of 0.51 nM. An energy minimized model of 3h revealed the major molecular interactions between HIV-1 protease active site and the tetrahydrofuranyl squaramide scaffold that may be responsible for its potent activity.

Implementing a Hybrid Expression Method That Allows Upper-Division Biochemistry Lab Students To Engage in a Full Protein Production Experience While Allowing Ample Time for Characterization Experiments.

Protein structure, function, and signaling are a large portion of biochemistry. Because of this, proteins are often used as model systems in biochemistry laboratory courses, where a course-long project might comprise protein expression, purification, and characterization. Two common protein expression methods are isopropyl ß-d-1-thiogalactopyranoside (IPTG) induction, which utilizes easy-to-make media but requires extensive cell-growth monitoring that is time-intensive, and autoinduction, which employs multicomponent media that are time-consuming to make but require no cell-growth monitoring. A protein expression method that is a hybrid of IPTG induction and autoinduction is presented. The hybrid method utilizes the medium of IPTG induction and the no-cell-growth-monitoring induction process of autoinduction, saving hands-on time in the protein expression phase to allow more time for protein characterization while still having students execute each step.

Design and Synthesis of Potent HIV-1 Protease Inhibitors Containing Bicyclic Oxazolidinone Scaffold as the P2 Ligands: Structure-Activity Studies and Biological and X-ray Structural Studies.

We have designed, synthesized, and evaluated a new class of potent HIV-1 protease inhibitors with novel bicyclic oxazolidinone derivatives as the P2 ligand. We have developed an enantioselective synthesis of these bicyclic oxazolidinones utilizing a key o-iodoxybenzoic acid mediated cyclization. Several inhibitors displayed good to excellent activity toward HIV-1 protease and significant antiviral activity in MT-4 cells. Compound 4k has shown an enzyme Ki of 40 pM and antiviral IC50 of 31 nM. Inhibitors 4k and 4l were evaluated against a panel of highly resistant multidrug-resistant HIV-1 variants, and their fold-changes in antiviral activity were similar to those observed with darunavir. Additionally, two X-ray crystal structures of the related inhibitors 4a and 4e bound to HIV-1 protease were determined at 1.22 and 1.30 Å resolution, respectively, and revealed important interactions in the active site that have not yet been explored.

Design, synthesis, and X-ray studies of potent HIV-1 protease inhibitors incorporating aminothiochromane and aminotetrahydronaphthalene carboxamide derivatives as the P2 ligands.

We describe the design, synthesis, and biological evaluation of a series of novel HIV-1 protease inhibitors with carboxamide derivatives as the P2 ligands. We have specifically designed aminothiochromane and aminotetrahydronaphthalene-based carboxamide ligands to promote hydrogen bonding and van der Waals interactions in the active site of HIV-1 protease. Inhibitors 4e and 4j have shown potent enzyme inhibitory and antiviral activity. High resolution X-ray crystal structures of 4d- and 4k-bound HIV-1 protease revealed molecular insights into the ligand-binding site interactions.

Enantioselective total synthesis of decytospolide A and decytospolide B using an Achmatowicz reaction.

Enantioselective syntheses of decytospolide A and decytospolide B are described here. The current synthesis highlights an Achmatowicz rearrangement of an optically active furanyl alcohol followed by reduction of the resulting dihydropyranone hemiacetal with BF3·OEt2 and Et3SiH to provide the saturated tetrahydropyranyl alcohol directly. This reduction was investigated with a variety of other Lewis acids. The synthesis also features Noyori asymmetric transfer hydrogenation and Friedel-Crafts acylation. Overall, the synthesis provides ready access to the natural products and may be useful in the preparation of bioactive derivatives.

IBD: microbiota manipulation through diet and modified bacteria.

BACKGROUND/AIMS: Crohn's disease (CD) and ulcerative colitis (UC) are both typified by an altered intestinal microbiota, and gene associations imply various defects in the mucosal barrier and in the innate immune response to bacteria. This review aims to assess how alterations in diet or use of modified bacteria could have therapeutic effects in CD or UC. METHODS: A MEDLINE search using the terms 'prebiotic', 'genetically modified bacteria', 'mucosal barrier in association with ulcerative colitis', 'Crohn's disease' or 'microbiota'. RESULTS: A large body of data from in vitro and animal studies shows promise for therapeutic approaches that target the microbiota. Approaches include dietary supplementation with fermentable fibres (prebiotics) and soluble fibres that block bacterial-epithelial adherence (contrabiotics), enhancement of the mucosal barrier with phosphatidylcholine, and use of genetically modified bacteria that express IL-10 or protease inhibitors. Vitamin D supplementation also shows promise, acting via enhancement of innate immunity. Clinical trials have shown benefit with enterically delivered phosphatidylcholine supplementation in UC and near-significant benefit with vitamin D supplementation in CD. CONCLUSION: Strategies that target the microbiota or the host defence against it appear to be good prospects for therapy and deserve greater investment.

Dietary supplementation with soluble plantain non-starch polysaccharides inhibits intestinal invasion of Salmonella Typhimurium in the chicken.

Soluble fibres (non-starch polysaccharides, NSP) from edible plants but particularly plantain banana (Musa spp.), have been shown in vitro and ex vivo to prevent various enteric pathogens from adhering to, or translocating across, the human intestinal epithelium, a property that we have termed contrabiotic. Here we report that dietary plantain fibre prevents invasion of the chicken intestinal mucosa by Salmonella. In vivo experiments were performed with chicks fed from hatch on a pellet diet containing soluble plantain NSP (0 to 200 mg/d) and orally infected with S.Typhimurium 4/74 at 8 d of age. Birds were sacrificed 3, 6 and 10 d post-infection. Bacteria were enumerated from liver, spleen and caecal contents. In vitro studies were performed using chicken caecal crypts and porcine intestinal epithelial cells infected with Salmonella enterica serovars following pre-treatment separately with soluble plantain NSP and acidic or neutral polysaccharide fractions of plantain NSP, each compared with saline vehicle. Bacterial adherence and invasion were assessed by gentamicin protection assay. In vivo dietary supplementation with plantain NSP 50 mg/d reduced invasion by S.Typhimurium, as reflected by viable bacterial counts from splenic tissue, by 98.9% (95% CI, 98.1-99.7; P<0.0001). In vitro studies confirmed that plantain NSP (5-10 mg/ml) inhibited adhesion of S.Typhimurium 4/74 to a porcine epithelial cell-line (73% mean inhibition (95% CI, 64-81); P<0.001) and to primary chick caecal crypts (82% mean inhibition (95% CI, 75-90); P<0.001). Adherence inhibition was shown to be mediated via an effect on the epithelial cells and Ussing chamber experiments with ex-vivo human ileal mucosa showed that this effect was associated with increased short circuit current but no change in electrical resistance. The inhibitory activity of plantain NSP lay mainly within the acidic/pectic (homogalacturonan-rich) component. Supplementation of chick feed with plantain NSP was well tolerated and shows promise as a simple approach for reducing invasive salmonellosis.

Why does the fallopian tube fail in ectopic pregnancy? The role of activins, inducible nitric oxide synthase, and MUC1 in ectopic implantation.

OBJECTIVE: To investigate the role of activin-ßA subunit, activin type II receptors, inducible nitric oxide synthase (iNOS), and MUC1 in the pathogenesis of ectopic pregnancy (EP) and their involvement in the determination of the implantation site. DESIGN: Observational study. SETTING: Academic unit of reproductive and developmental medicine. PATIENT(S): Four women at the luteal phase, three pseudopregnant women at the time of hysterectomy for benign disease, and 10 archived cases of EP. We collected 14 Fallopian tubes were collected from four women at the luteal phase and three pseudopregnant women at the time of hysterectomy for benign disease; specimens from implantation site, trophoblast and remote sites from the implantation site were collected from 10 archived cases of EP. INTERVENTION(S): Immunohistochemistry and quantitative reverse-transcriptase polymerase chain reaction (RT-PCR). MAIN OUTCOME MEASURE(S): Comparison of the expression of candidate molecules between the different groups. RESULT(S): The expression of activin-ßA subunit, activin type II receptors, and iNOS was statistically significantly increased and expression of MUC1 statistically significantly decreased in tubes bearing an EP. There was no statistically significant difference in the expression of the candidate molecules between the implantation and remote sites. Candidate molecules were also expressed in the trophoblast. CONCLUSION(S): The pathological expression of candidate molecules by tubes bearing an EP is not involved in the determination of implantation site. Additionally, candidate molecules may play a role in the regulation of trophoblast cells in vivo during early pregnancy.

Cyanobacteria cultivation in industrial wastewaters and biodiesel production from their biomass: a review.

As an alternative fuel biodiesel has become increasingly important due to diminishing petroleum reserves and adverse environmental consequences of exhaust gases from petroleum-fueled engines. Recently, research interest has focused on the production of biofuel from microalgae. Cyanobacteria appeared to be suitable candidates for cultivation in wastes and wastewaters because they produce biomass in satisfactory quantity and can be harvested relatively easily due to their size and structure. In addition, their biomass composition can be manipulated by several environmental and operational factors to produce biomass with concrete characteristics. Herein, we review the culture of cyanobacteria in wastewaters and also the potential resources that can be transformed into biodiesel successfully for meeting the ever-increasing demand for biodiesel production.