Analysis of two pheromone-responsive conjugative multiresistance plasmids carrying the novel mobile optrA locus from Enterococcus faecalis

Background: The acquired optrA gene, which encodes a ribosomal protection protein of the ABC-F family, can confer cross-resistance to linezolid and florfenicol, posing a serious therapeutic challenge to both human and veterinary medicine. Purpose: The objective of this study was to investigate the two Enterococcus faecalis (E. faecalis) plasmids for their fine structure, their transferability and the presence of mobile antimicrobial resistance loci. Methods: To elucidate their fine structure, the two plasmids were completely sequenced and the sequences analysed. Besides conjugation experiments, inverse PCR assays were conducted to see whether minicircles are produced from the mobile antimicrobial resistance loci. Results: Two pheromone-responsive conjugative optrA-carrying plasmids from E. faecalis, pE211 and pE508 were identified, which can transfer with frequencies of 2.6 ×10−2 and 3.7 ×10−2 (transconjugant per donor), respectively. In both plasmids, optrA was located on the novel mobile optrA locus with different sizes (12,834 bp in pE211 and 7,561 bp in pE508, respectively), flanked by two copies of IS1216 genes in the same orientation. Inverse PCR revealed that circular forms can be generated, consisting of optrA and one copy of IS1216, indicating they are all active. The 77,562 bp plasmid pE211 also carried Tn558 and a mobile bcrABDR locus, and the 84,468 bp plasmid pE508 also harbored the genes fexA, tet(L), tet(O/W/32/O) and a mobile aac(A)-aph(D) locus. Conclusion: The presence of mobile genetic elements in these plasmids renders them flexible and these elements will aid to the persistence and dissemination of these plasmids among enterococci and potentially also other gram-positive bacteria

Bis[N′-(3-cyano­benzyl­idene)isonicotino­hydrazide]silver(I) trifluoro­acetate

In the title compound, [Ag(C14H10N4O)2]CF3CO2, the AgI ion is coordinated by two N atoms of the pyridine rings of two N′-(3-cyano­benzyl­idene)isonicotinohydrazide ligands in a nearly linear geometry. In the crystal structure, a combination of close contacts formed via Ag⋯N inter­actions [Ag⋯N = 3.098 (2) and 3.261 (2) Å] from symmetry-related mol­ecules and inter­molecular N—H⋯O hydrogen bonds between CF3CO2 − anions and the hydrazone groups of two ligands give rise to chains. Furthermore, there are Ag⋯O inter­actions with a separation of 2.765 (2) Å between chains. The F atoms of the CF3CO2 − anion are disordered over two sites with refined occupancies of 0.593 (5) and 0.407 (5)

Studies on the protective effect of total flavonoids from Cichorium glandulosum roots against carbon tetrachloride-induced liver fibrosis in rats

Purpose: To study the protective influence of total flavonoids from Cichorium glandulosum roots (TFCG) against carbon tetrachloride-mediated hepatic fibrosis in rats, and the probable mechanism of action involved.Methods: Rats with liver fibrosis were orally administered TFCG (50, 100 or 200 mg/kg) once a day for 13 weeks. Liver index and liver injury indices in serum alanine aminotransferase (ALT), aspartate aminotransferase (AST), alkaline phosphatase (AKP), lactate dehydrogenase (LDH), γ-glutamyl transpeptidase (γ-GT), hydroxyproline (HYP), albumin (ALB) and malondialdehyde (MDA) were determined using electronic balance or corresponding assay kits, as appropriate. Following staining with hematoxylin and eosin and Van Gieson, histopathological changes in liver tissues were examined by light microscopy. TGF-β/Smad pathway-related protein expressions in liver tissues, viz, transforming growth factor-β1 (TGF-β1), mothers against decapentaplegic homolog 3 (Smad3), Smad7, toll-like receptor 4 (TLR4) and α-smooth muscle actin (α-SMA) were determined using immunohistochemical techniques.Results: Exposure to TFCG significantly reversed abnormal serum levels of ALT, AST, AKP, LDH, γ- GT, HYP, ALB and MDA rats with liver fibrosis to normal levels, and also decreased their liver index values (p < 0.01). Moreover, TFCG improved histopathological changes in the liver tissues of fibrotic rats, and significantly reversed abnormal TGF-β1, Smad3, Smad7, TLR4 and α-SMA protein expressions in the liver tissues of fibrotic rats to normal levels (p < 0.05 or 0.01).Conclusion: These results indicate that TFCG exerts protective effect against liver fibrosis via a mechanism related to inactivation of TGF-β/Smad pathway. Thus, TFCG may find application in liver fibrosis therapy.Keywords: Cichorium glandulosum, Flavonoids, Liver, Fibrosis, TGF-β/Smad pathwa

Isolation and Characterization of Polymorphic Microsatellite Markers for Two Subterranean Termites

We isolated 15 and 18 highly polymorphic genomic microsatellite markers from two subterranean termites, Reticulitermes aculabialis and R. labralis, respectively. A total of 53 alleles were detected in 15 microsatellite loci of R. aculabialis, and the alleles were 3.533±1.302 (mean±SD), while the corresponding data of R. labralis were 115 detected alleles in 18 microsatellite loci with 6.389±1.754 alleles. The observed and expected heterozygosity was 0.496±0.236 and 0.564±0.125 in R. aculabialis, and 0.368±0.263 and 0.702±0.115 in R. labralis, respectively. Seven loci were highly polymorphic (PIC>0.5) in R. aculabialis, and 15 loci were highly polymorphic (PIC>0.5) in R. labralis. All loci showed Hardy–Weinberg equilibrium. These polymorphic markers provide useful tools for population genetic and breeding system studies of subterranean termites

{μ-N-[(Diphenyl­phosphino)meth­yl]pyridin-2-amine-κ2 N 1:P}bis­{[2-(2,2′-bipyridin-6-yl)phenyl-κ3 N,N′,C 1]platinum(II)} bis­(perchlorate)

The title compound, [Pt2(C16H11N2)2(C18H17N2P)](ClO4)2, contains two PtII atoms, bridged by an N-[(diphenyl­phosphino)meth­yl]pyridin-2-amine (dppmp) ligand. One Pt atom is coordinated by one P atom from the dppmp ligand, and one C atom and two N atoms from a 6-phenyl-2,2′-bipyridine (pbpy) ligand in a square-planar geometry. The other Pt atom is coordinated by one N atom from the dppmp ligand, and one C atom and two N atoms from another pbpy ligand in a square-planar geometry. There are intra­molecular π–π inter­actions between the pbpy ligands, with a centroid–centroid distance of 3.62 (1) Å between two pyridyl rings. The oxygen atoms of both perchlorate anions are disordered, each over two different positions [occupanicies 0.49 (3)/0.51 (3) and 0.48 (2)/0.52 (2)]