52 research outputs found

    Lectin-mediated bacterial modulation by the intestinal nematode Ascaris suum

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    Ascariasis is a global health problem for humans and animals. Adult Ascaris nematodes are long-lived in the host intestine where they interact with host cells as well as members of the microbiota resulting in chronic infections. Nematode interactions with host cells and the microbial environment are prominently mediated by parasite-secreted proteins and peptides possessing immunomodulatory and antimicrobial activities. Previously, we discovered the C-type lectin protein AsCTL-42 in the secreted products of adult Ascaris worms. Here we tested recombinant AsCTL-42 for its ability to interact with bacterial and host cells. We found that AsCTL-42 lacks bactericidal activity but neutralized bacterial cells without killing them. Treatment of bacterial cells with AsCTL-42 reduced invasion of intestinal epithelial cells by Salmonella. Furthermore, AsCTL-42 interacted with host myeloid C-type lectin receptors. Thus, AsCTL-42 is a parasite protein involved in the triad relationship between Ascaris, host cells, and the microbiota

    Mental health of UK hospitality Workers: Shame, self-criticism and self-reassurance

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    This study aimed to evaluate shame for mental health problems, and explore relationships between shame, self-criticism, self-reassurance, and mental health among UK hospitality workers, because this group of workers suffer from poor mental health yet report strong shame. An opportunity sample of 114 UK hospitality workers completed measures examining shame for mental health problems, self-criticism, self-reassurance, and mental health problems. A high proportion of workers scored over the midpoint in almost all the shame subscales. Shame, self-criticism, self-reassurance, and mental health were related to one another. External shame and self-criticism were positive predictors, and self-reassurance was a negative predictor for mental health problems. While self-criticism moderated the relationship between shame and mental health problems, self-reassurance did not. Online compassion training was recommended as it can reduce self-criticism and shame, can be undertaken without colleagues knowing and tailored to specific work patterns.N/

    Rearrangements of Acyl, Thioacyl, and Imidoyl (Thio)cyanates to Iso(thio)cyanates, Acyl Iso(thio)cyanates to (Thio)acyl Isocyanates, and Imidoyl Iso(thio)cyanates to (Thio)acyl Carbodiimides, RCX-YCN reversible arrow RCX-NCY reversible arrow RCY-NCX rever

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    Two types of rearrangements have been investigated computationally at the B3LYP/6-311+G(d,p) level. The activation barriers for rearrangement of acyl thiocyanates RCO-SCN to the corresponding isothiocyanates RCO-NCS are 30-31 kcal/mol in agreement with the observation that the thiocyanates are in some cases isolable albeit very sensitive compounds. Alkoxycarbonyl-, (alkylthio)carbonyl- and carbamoyl thiocyanates are isolable and have higher calculated barriers (ca. 40 kcal/mol) toward rearrangement to isothiocyanates, whereas all thioacyl thiocyanate derivatives are rather unstable compounds with barriers in the range 20-30 kcal/mol for rearrangement to the isothiocyanates. Acyl-, alkoxycarbonyl-, and carbamoyl cyanates R-CO-OCN are predicted to be in some cases isolable compounds with barriers up to ca. 40 kcal/mol for rearrangement to the isocyanates RCO-NCO. All of the rearrangements of this type involve the HOMO of a nearly linear (thio)cyanate anion and the LUMO of the acyl cation, in particular the acyl =X π* orbital. The second type of rearrangement involves 1,3-shifts of the groups R attached to the (thio)acyl groups, that is, acyl isothiocyanate-thioacyl isocyanate and imidoyl isothiocyanate-thioacyl carbodiimide rearrangements. These reactions involve four-membered cyclic, zwitterionic transition states facilitated by lone pair-LUMO interactions between the migrating R group and the neighboring iso(thio)cyanate function. Combination of the two rearrangements leads to the general reaction scheme RCX-YCN ⇌ RCX-NCY ⇌ RCY-NCX ⇌ RCY-XCN (X and Y = O, S, NR′)

    Visible-light mediated oxidative ring expansion of anellated cyclopropanes to fused endoperoxides with antimalarial activity

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    A visible light mediated ring expansion of readily available carbo- and heterocyclic anellated cyclopropanes by molecular oxygen at ambient pressure has been developed. Tolerating a variety of functional groups, the reaction yields fused 1,2-dioxolanes, which were tested for antimalarial activity given their close analogy to the active principle of approved drugs such as artemisinin

    Reaction of aminosulfenates with chloramine B

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    Generation of glycan-specific nanobodies

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    The development of antibodies that target specific glycan structures on cancer cells or human pathogens poses a significant challenge due to the immense complexity of naturally occurring glycans. Automated glycan assembly enables the production of structurally homogeneous glycans in amounts that are difficult to derive from natural sources. Nanobodies (Nbs) are the smallest antigen-binding domains of heavy-chain-only antibodies (hcAbs) found in camelids. To date, the development of glycan-specific Nbs using synthetic glycans has not been reported. Here, we use defined synthetic glycans for alpaca immunization to elicit glycan-specific hcAbs, and describe the identification, isolation, and production of a Nb specific for the tumor-associated carbohydrate antigen Globo-H. The Nb binds the terminal fucose of Globo-H and recognizes synthetic Globo-H in solution and native Globo-H on breast cancer cells with high specificity. These results demonstrate the potential of our approach for generating glycan-targeting Nbs to be used in biomedical and biotechnological applications
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