Analysis of interspecies adherence of oral bacteria using a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis profiling.

Information on co-adherence of different oral bacterial species is important for understanding interspecies interactions within oral microbial community. Current knowledge on this topic is heavily based on pariwise coaggregation of known, cultivable species. In this study, we employed a membrane binding assay coupled with polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) to systematically analyze the co-adherence profiles of oral bacterial species, and achieved a more profound knowledge beyond pairwise coaggregation. Two oral bacterial species were selected to serve as "bait": Fusobacterium nucleatum (F. nucleatum) whose ability to adhere to a multitude of oral bacterial species has been extensively studied for pairwise interactions and Streptococcus mutans (S. mutans) whose interacting partners are largely unknown. To enable screening of interacting partner species within bacterial mixtures, cells of the "bait" oral bacterium were immobilized on nitrocellulose membranes which were washed and blocked to prevent unspecific binding. The "prey" bacterial mixtures (including known species or natural saliva samples) were added, unbound cells were washed off after the incubation period and the remaining cells were eluted using 0.2 mol x L(-1) glycine. Genomic DNA was extracted, subjected to 16S rRNA PCR amplification and separation of the resulting PCR products by DGGE. Selected bands were recovered from the gel, sequenced and identified via Nucleotide BLAST searches against different databases. While few bacterial species bound to S. mutans, consistent with previous findings F. nucleatum adhered to a variety of bacterial species including uncultivable and uncharacterized ones. This new approach can more effectively analyze the co-adherence profiles of oral bacteria, and could facilitate the systematic study of interbacterial binding of oral microbial species

Penta­aqua­(1H-benzimidazole-5,6-dicarboxyl­ato-κN 3)nickel(II) penta­hydrate

In the title mononuclear complex, [Ni(C9H4N2O4)(H2O)5]·5H2O, the NiII atom is six-coordinated by one N atom from a 1H-benzimidazole-5,6-dicarboxyl­ate ligand and by five O atoms from five water mol­ecules and displays a distorted octa­hedral geometry. Inter­molecular O—H⋯O hydrogen-bonding inter­actions among the coordinated water mol­ecules, solvent water mol­ecules and carboxyl O atoms of the organic ligand and additional N—H⋯O hydrogen bonding lead to the formation of a three-dimensional supra­molecular network

Diaqua­bis­(5-carb­oxy-2-propyl-1H-imidazole-4-carboxyl­ato-κ2 N 3,O 4)nickel(II) tetra­hydrate

In the title complex, [Ni(C8H9N2O4)2(H2O)2]·4H2O, the NiII ion is coordinated in a slightly distorted octa­hedral environment formed by two bis-chelating H2pimda (H3pimda is 2-propyl-1H-4,5-dicarb­oxy­lic acid) ligands and two coordinated water mol­ecules. In the crystal structure, a three-dimensional framework is formed by inter­molecular O—H⋯O and N—H⋯O hydrogen bonds involving the solvent water mol­ecules, coordinated water mol­ecules, carboxyl­ate O atoms and the protonated N atoms of the H2pimda ligands. The propyl groups of each H2pimda ligand are disordered over two sets of sites with refined occupancies of 0.50 (2):0.50 (2) and 0.762 (11):0.238 (11). In one water solvent mol­ecule, one of the H atoms was refined as disordered over two sites of equal occupancy

Diaqua­bis­(4-carb­oxy-2-propyl-1H-imidazole-5-carboxyl­ato-κ2 N 3,O 4)cobalt(II) N,N-dimethyl­formamide disolvate

In the title complex, [Co(C8H9N2O4)2(H2O)2]·2C3H7NO, the CoII cation (site symmetry ) is six-coordinated by two 5-carb­oxy-2-propyl-1H-imidazole-4-carboxyl­ate ligands and two water mol­ecules in a distorted octa­hedral environment. In the crystal structure, the complex mol­ecules and dimethyl­formamide solvent mol­ecules are linked by extensive O—H⋯O and N—H⋯O hydrogen bonding into sheets lying parallel to (21)

Hexaaqua­nickel(II) 4,4′-(1,2-dihy­droxy­ethane-1,2-di­yl)dibenzoate monohydrate

In the title compound, [Ni(H2O)6](C16H12O6)·H2O, the NiII cation is located on a mirror plane and is coordinated by six water mol­ecules, two of which are also located on the mirror plane, in a distorted octa­hedral geometry. The 4,4′-(1,2-dihy­droxy­ethane-1,2-di­yl)dibenzoate anion is centrosymmetric with the mid-point of the central ethane C—C bond located on an inversion center. The uncoordinated water mol­ecule is located on a mirror plane. Extensive O—H⋯O hydrogen bonding is present in the crystal structure