Ail Proteins of Yersinia pestis and Y. pseudotuberculosis Have Different Cell Binding and Invasion Activities

The Yersinia pestis adhesin Ail mediates host cell binding and facilitates delivery of cytotoxic Yop proteins. Ail from Y. pestis and Y. pseudotuberculosis is identical except for one or two amino acids at positions 43 and 126 depending on the Y. pseudotuberculosis strain. Ail from Y. pseudotuberculosis strain YPIII has been reported to lack host cell binding ability, thus we sought to determine which amino acid difference(s) are responsible for the difference in cell adhesion. Y. pseudotuberculosis YPIII Ail expressed in Escherichia coli bound host cells, albeit at ∼50% the capacity of Y. pestis Ail. Y. pestis Ail single mutants, Ail-E43D and Ail-F126V, both have decreased adhesion and invasion in E. coli when compared to wild-type Y. pestis Ail. Y. pseudotuberculosis YPIII Ail also had decreased binding to the Ail substrate fibronectin, relative to Y. pestis Ail in E. coli. When expressed in Y. pestis, there was a 30–50% decrease in adhesion and invasion depending on the substitution. Ail-mediated Yop delivery by both Y. pestis Ail and Y. pseudotuberculosis Ail were similar when expressed in Y. pestis, with only Ail-F126V giving a statistically significant reduction in Yop delivery of 25%. In contrast to results in E. coli and Y. pestis, expression of Ail in Y. pseudotuberculosis led to no measurable adhesion or invasion, suggesting the longer LPS of Y. pseudotuberculosis interferes with Ail cell-binding activity. Thus, host context affects the binding activities of Ail and both Y. pestis and Y. pseudotuberculosis Ail can mediate cell binding, cell invasion and facilitate Yop delivery.     

Caffeoylquinic Acids,Cytotoxic, Antioxidant,Acetylcholinesterase and Tyrosinase Enzyme Inhibitory Activities of Six Inula Species from Bulgaria

Chlorogenic (5‐CQA), 1,5‐, 3,5‐, 4,5‐ and 3,4‐dicaffeoylquinic (DCQA) acids were identified and quantified in the methanol extracts of Inula oculus‐christi L., I. bifrons L., I. aschersoniana Janka var. aschersoniana, I. ensifolia L., I. conyza (Griess .) DC. and I. germanica L. by HPLC analysis. The amount of 5‐CQA varied from 5.48 to 28.44 mg/g DE and the highest content was detected in I. ensifolia. 1,5‐DCQA (4.05–55.25 mg/g DE) was the most abundant dicaffeoyl ester of quinic acid followed by 3,5‐DCQA, 4,5‐DCQA and 3,4‐DCQA. The extract of I. ensifolia showed the highest total phenolic content (119.92±0.95 mg GAE/g DE) and exhibited the strongest DPPH radical scavenging activity (69.41±0.55 %). I. bifrons extract was found to be the most active sample against ABTS^.+ (TEAC 0.257±0.012 mg/mL) and the best tyrosinase inhibitor. The studied extracts demonstrated a low inhibitory effect towards acetylcholinesterase and possessed low cytotoxicity in concentration range from 10 to 300 μg/mL toward non‐cancer (MDCK II) and cancer (A 549) cells.     

Photosynthesis supported by a chlorophyll f-dependent,entropy-driven uphill energy transfer in Halomicronema hongdechloris cells adapted to far-red light

Photosynthesis Research - The phototrophic cyanobacterium Halomicronema hongdechloris shows far-red light-induced accumulation of chlorophyll (Chl) f, but the involvement of the pigment in...     

Phenotyping of isogenic chlorophyll-less bread and durum wheat mutant lines in relation to photoprotection and photosynthetic capacity

Photosynthesis Research - In our experiments, we examined high light responses and photosynthetic capacity of chlorophyll-less isogenic mutant lines of hexaploid bread wheat (Triticum aestivum L.)...     

Crop photosynthesis for the twenty-first century

Photosynthesis Research -     

SANS (USH1G) regulates pre-mRNA splicing by mediating the intra-nuclear transfer of tri-snRNP complexes

Splicing is catalyzed by the spliceosome, a compositionally dynamic complex assembled stepwise on pre-mRNA. We reveal links between splicing machinery components and the intrinsically disordered ciliopathy protein SANS. Pathogenic mutations in SANS/USH1G lead to Usher syndrome—the most common cause of deaf-blindness. Previously, SANS was shown to function only in the cytosol and primary cilia. Here, we have uncovered molecular links between SANS and pre-mRNA splicing catalyzed by the spliceosome in the nucleus. We show that SANS is found in Cajal bodies and nuclear speckles, where it interacts with components of spliceosomal sub-complexes such as SF3B1 and the large splicing cofactor SON but also with PRPFs and snRNAs related to the tri-snRNP complex. SANS is required for the transfer of tri-snRNPs between Cajal bodies and nuclear speckles for spliceosome assembly and may also participate in snRNP recycling back to Cajal bodies. SANS depletion alters the kinetics of spliceosome assembly, leading to accumulation of complex A. SANS deficiency and USH1G pathogenic mutations affects splicing of genes related to cell proliferation and human Usher syndrome. Thus, we provide the first evidence that splicing dysregulation may participate in the pathophysiology of Usher syndrome.     

Curcumin prevents liver fat accumulation and serum fetuin-A increase in rats fed a high-fat diet

Fetuin-A is synthesized in the liver and is secreted into the bloodstream. Clinical studies suggest involvement of fetuin-A in metabolic disorders such as visceral obesity, insulin resistance, diabetes, and fatty liver. Curcumin is extracted from the rhizome Curcuma longa and has been shown to possess potent antioxidant, anticarcinogenic, anti-inflammatory, and hypoglycemic properties. In this study, we investigated the effect of curcumin treatment on serum fetuin-A levels as well as hepatic lipids and prooxidant–antioxidant status in rats fed a high-fat diet (HFD). Male Sprague–Dawley rats were divided into six groups. Group 1 was fed control diet (10 % of total calories from fat). Groups 2 and 3 were given curcumin (100 and 400 mg/kg bw/day, respectively ) by gavage for 8 weeks and were fed control diet. Group 4 was fed with HFD (60 % of total calories from fat). Groups 5 and 6 received HFD together with the two doses of curcumin, respectively. Curcumin treatment appeared to be effective in reducing liver triglycerides and serum fetuin-A levels. These findings suggest that the reduction of fetuin-A may contribute to the beneficial effects of curcumin in the pathogenesis of obesity.