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The genus Oxalis contains important species worldwide with great economic and edible values. However, the testing guidelines have not been furbished, especially in China. Oxalis germplasm, including 60 species and 125 varieties, was collected from home and abroad and extensive field trials and phenotypic observations were conducted along with quantitative taxonomy, observations, correlation analysis and cluster analysis. Under the test guidelines of the International Union for the Protection of New Plant Varieties (UPOV), general guidelines for testing for distinctness, uniformity, stability (DUS) of new plant varieties, and Japanese test guidelines for DUS of Oxalis , 96 test characteristics (38 qualitative characteristics, 28 quantitative characteristics and 30 pseudo-qualitative characteristics) were determined as DUS test characteristics of Oxalis. Each test characteristic was scientifically graded and accurately described, and standard varieties and characteristic diagrams were provided for some characteristics. The guidelines for testing DUS of new plant varieties of Oxalis provide a standard for examining and testing new varieties of plants. [ABSTRACT FROM AUTHOR]

Background: Zinc deficiency is known to result in epithelial barrier leak in the GI tract. Precise effects of zinc on epithelial tight junctions (TJs) are only beginning to be described and understood. Along with nutritional regimens like methionine-restriction and compounds such as berberine, quercetin, indole, glutamine and rapamycin, zinc has the potential to function as a TJ modifier and selective enhancer of epithelial barrier function. Aims: The purpose of this study was to determine the effects of zinc-supplementation on the TJs of a well-studied in vitro GI model, CACO-2 cells. Methods: Barrier function was assessed electrophysiologically by measuring transepithelial electrical resistance (R), and radiochemically, by measuring transepithelial (paracellular) diffusion of C-D-mannitol and C-polyethyleneglycol. TJ composition was studied by Western immunoblot analyses of occludin, tricellulin and claudins-1 to -5 and -7. Results: Fifty- and 100-μM zinc concentrations (control medium is 2 μM) significantly increase R but simultaneously increase paracellular leak to D-mannitol. Claudins 2 and 7 are downregulated in total cell lysates, while occludin, tricellulin and claudins-1, -3, -4 and -5 are unchanged. Claudins-2 and -7 as well as tricellulin exhibit decreased cytosolic content as a result of zinc supplementation. Conclusions: Zinc alters CACO-2 TJ composition and modifies TJ barrier function selectively. Zinc is one of a growing number of 'nutraceutical' substances capable of enhancing epithelial barrier function, and may find use in countering TJ leakiness induced in various disease states. [ABSTRACT FROM AUTHOR]

The beneficial effects of caloric restriction in increasing longevity and forestalling age-related diseases are well known. Dietary restriction of methionine also renders similar benefits. We recently showed in a renal epithelial cell culture system that reduction of culture medium methionine by 80% resulted in altered tight junctional (TJ) claudin composition and also improved epithelial barrier function (51). In the current study, we examined the effect of dietary restriction of methionine on TJ barrier function in rat gastrointestinal tissue to see whether this phenomenon also holds true in a tissue model and for a different epithelial cell type. After 28 days on methionine-restricted (MR) diet, rats showed small but significant reductions in the plasma and (intracellular) colonocyte levels of methionine. Colon mucosal sheets from rats on the MR diet showed increased transepithelial electrical resistance with concomitant decrease in paracellular diffusion of 14C-D-mannitol, suggesting improved barrier function relative to rats on control diet. This improved barrier function could not be explained by changes in colon crypt length or frequency. Neither was the colonocyte mitotic index nor the apoptotic frequency altered significantly. However, TJ composition/structure was being altered by the MR diet. RT-PCR and Western blot analysis showed an increase in the abundance of claudin-3 and an apparent change in the posttranslational modification of occludin, data reinforcing a paracellular barrier alteration. Overall, our data suggest that reduction in dietary intake of methionine results in improved epithelial barrier function by inducing altered TJ protein composition. [ABSTRACT FROM AUTHOR]

Abstract: We compared the effectiveness of two absorption promoters, sodium caprate (C10) and melittin, in increasing the bioavailability (F) of poorly absorbed paracellular flux markers across the intestinal mucosae of rats in situ, together with examination of their effects on morphology. C10 (100mM) and melittin (50μM) significantly increased absorption of FITC-dextran-4kDa (FD4) following jejunal and colonic instillations. F of FD4 following jejunal instillations with C10 was increased from 0.07% to 2.3%, while it was increased from 0.07% to 0.53% in the presence of melittin. F of FD4 following colonic instillations with C10 was increased from 1% to 33% while melittin increased it from 1% to 7%. F of FD70 was unchanged in colonic instillations in the presence of either of the two agents, indicating size limitations of the permeability enhancement effects. In rat jejunal perfusions, C10 (50mM) and melittin (50μM) significantly increased [14C]-mannitol permeability by 9- and 1.9-fold respectively. C10 was more effective than melittin in increasing fluxes in all models. Histology of intestinal sections exposed to either promoter showed mild mucosal damage at those concentrations effective at promoting absorption. Electron microscopy revealed epithelial cell damage induced by both enhancers accompanied by truncation of microvilli, and sloughing. Overall, both melittin and C10 improved bioavailability of polar sugars across the jejunum and colon of rats in situ, which was associated with some degree of mucosal damage. [Copyright &y& Elsevier]

Abstract: Salmon calcitonin (sCT) was conjugated via its N-terminal cysteine to a comb-shaped end-functionalized poly(poly(ethylene glycol) methyl ether methacrylate) (PolyPEG®, 6.5 kDa), and to linear PEG (5 kDa). Conjugate molecular weight and purity was assessed by SEC–HPLC and MALDI–TOF MS. Bioactivity of conjugates was measured by cyclic AMP assay in T47D cells. Calcium and calcitonin levels were measured in rats following intravenous injections. Stability of conjugates was tested against serine proteases, intestinal and liver homogenates and serum. Cytotoxicity of conjugates was assessed by lactate dehydrogenase (LDH) assay and by haemolytic assay of rat red blood cells. Results showed that the two conjugates were of high purity with molecular weights similar to predictions. Both conjugates retained more than 85% bioactivity in vitro and had nanomolar EC50 values similar to sCT. While both sCT-PolyPEG®6.5 K and sCT-PEG5 K were resistant to metabolism by serine proteases, homogenates and serum, PolyPEG®6.5 K was more so. Although both conjugates reduced serum calcium to levels similar to those achieved with sCT, PolyPEG®6.5 K extended the T 1/2 and AUC of serum sCT over values achieved with sCT-PEG and sCT itself. None of PolyPEG®, PEG or methacrylic acid displayed significant cytotoxicity. PolyPEG® may therefore have potential to improve pharmacokinetic profiles of injected peptides. [Copyright &y& Elsevier]

Abstract: Salmon calcitonin (sCT) was conjugated via cysteine-1 to novel comb-shaped end-functionalised (poly(PEG) methyl ether methacrylate) (sCT-P) polymers, to yield conjugates of total molecular weights (MW) inclusive of sCT: 6.5, 9.5, 23 and 40kDa. The conjugates were characterised by HPLC and their in vitro and in vivo bioactivity was measured by cAMP assay on human T47D cells and following intravenous (i.v.) injection to rats, respectively. Stability against endopeptidases, rat serum and liver homogenates was assessed. There were linear and exponential relationships between conjugate MW with potency and efficacy respectively, however the largest MW conjugate still retained 70% of Emax and an EC50 of 3.7nM. In vivo, while free sCT and the conjugates reduced serum [calcium] to a maximum of 15–30% over 240min, the half-life (T1/2) was increased and the area under the curve (AUC) was extended in proportion to conjugate MW. Likewise, the polymer conferred protection on sCT against attack by trypsin, chymotrypsin, elastase, rat serum and liver homogenates, with the best protection afforded by sCT-P (40kDa). Mathematical modelling accurately predicted the MW relationships to in vitro efficacy, potency, in vivo PK and enzymatic stability. With a significant increase in T1/2 for sCT, the 40kDa MW comb-shaped PEG conjugate of sCT may have potential as a long-acting injectable formulation. [ABSTRACT FROM AUTHOR]

Abstract: The effects of two absorption promoters, (sodium caprate (C10) and melittin), on intestinal permeability and viability were measured in intact rat and human colonic epithelia mounted in Ussing chambers. Apical-side addition of C10 (10mM) and melittin (10–50μM) rapidly reduced the transepithelial electrical resistance (TEER) and increased the apparent permeability coefficient (Papp) of [14C]-mannitol and FITC-dextran-4kDa (FD4) across colonic mucosae from both species. Effects of C10 on flux were greater than those of melittin at the concentrations selected. C10 irreversibly decreased TEER, but the effects of melittin were partially reversible. Enhanced permeability of polar sugars (0.18–70kDa) in colonic mucosae with C10 was accompanied by significant release of lactate dehydrogenase (LDH) from the luminal surface as well as by inhibition of electrogenic chloride secretion induced by the muscarinic agonist, carbachol (0.1–10μM). Although melittin did not alter electrogenic chloride secretion in rat or human colonic mucosae, it caused leakage of LDH from rat tissue. Gross histology and electron microscopy of rat and human colonic mucosae demonstrated that each permeation enhancer can induce colonic epithelial damage at concentrations required to increase marker fluxes. C10 led to more significant mucosal damage than melittin, characterised by sloughing and mucosal erosion. Overall, these results indicate that while C10 and melittin increase transport of paracellular flux markers across isolated human and rat colonic mucosae in vitro, these effects are associated with some cytotoxicity. [Copyright &y& Elsevier]

We employ water-soluble organic phosphines as key reagents in a one-pot synthetic protocol where a (poly)peptide disulfide bridge is first reduced followed by subsequent reaction of the two thiols in situwith poly(monomethoxy ethylene glycol)(meth)acrylates (p(mPEG)(M)A); we use salmon calcitonin (sCT) as a disulfide bridge-containing peptide, which contains a disulfide bridge—Cys1–Cys7—that can be reduced to give two sulfhydryl units available for thiol functionalisation; bioactivity is retained. [ABSTRACT FROM AUTHOR]