Comparative analysis of the human saliva microbiome from different climate zones: Alaska, Germany, and Africa

Background: Although the importance of the human oral microbiome for health and disease is increasingly recognized, variation in the composition of the oral microbiome across different climates and geographic regions is largely unexplored. Results: Here we analyze the saliva microbiome from native Alaskans (76 individuals from 4 populations), Germans (10 individuals from 1 population), and Africans (66 individuals from 3 populations) based on next-generation sequencing of partial 16S rRNA gene sequences. After quality filtering, a total of 67,916 analyzed sequences resulted in 5,592 OTUs (defined at ≥97% identity) and 123 genera. The three human groups differed significantly by the degree of diversity between and within individuals (e.g. beta diversity: Africans > Alaskans > Germans; alpha diversity: Germans > Alaskans > Africans). UniFrac, network, ANOSIM, and correlation analyses all indicated more similarities in the saliva microbiome of native Alaskans and Germans than between either group and Africans. The native Alaskans and Germans also had the highest number of shared bacterial interactions. At the level of shared OTUs, only limited support for a core microbiome shared across all three continental regions was provided, although partial correlation analysis did highlight interactions involving several pairs of genera as conserved across all human groups. Subsampling strategies for compensating for the unequal number of individuals per group or unequal sequence reads confirmed the above observations. Conclusion: Overall, this study illustrates the distinctiveness of the saliva microbiome of human groups living under very different climatic conditions

Comparative analysis of the human saliva microbiome from different climate zones: Alaska, Germany, and Africa

Background: Although the importance of the human oral microbiome for health and disease is increasingly recognized, variation in the composition of the oral microbiome across different climates and geographic regions is largely unexplored. Results: Here we analyze the saliva microbiome from native Alaskans (76 individuals from 4 populations), Germans (10 individuals from 1 population), and Africans (66 individuals from 3 populations) based on next-generation sequencing of partial 16S rRNA gene sequences. After quality filtering, a total of 67,916 analyzed sequences resulted in 5,592 OTUs (defined at ≥97% identity) and 123 genera. The three human groups differed significantly by the degree of diversity between and within individuals (e.g. beta diversity: Africans > Alaskans > Germans; alpha diversity: Germans > Alaskans > Africans). UniFrac, network, ANOSIM, and correlation analyses all indicated more similarities in the saliva microbiome of native Alaskans and Germans than between either group and Africans. The native Alaskans and Germans also had the highest number of shared bacterial interactions. At the level of shared OTUs, only limited support for a core microbiome shared across all three continental regions was provided, although partial correlation analysis did highlight interactions involving several pairs of genera as conserved across all human groups. Subsampling strategies for compensating for the unequal number of individuals per group or unequal sequence reads confirmed the above observations. Conclusion: Overall, this study illustrates the distinctiveness of the saliva microbiome of human groups living under very different climatic conditions. Electronic supplementary material The online version of this article (doi:10.1186/s12866-014-0316-1) contains supplementary material, which is available to authorized users

Synthesis and structural characterization of bis(salicylaldiminato) magnesium complexes of varying aggregation and coordination state

A series of salicylaldiminato ligands [C6H5N=CHC 6H4OH (1L), 2,6-iPrC6H 3N=CHC6H4OH (2L), and 2,6-iPrC 6H3N=CH-3,5-tBu2C6H2OH (3L)] were treated with Bu2Mg in the presence of the appropriate solvent system to yield the crystalline compounds [( 1L6Mg3)·thf] (1), [(2L 2Mg·thf)] (2), and [3L2Mg] (3). The products were characterized by 1H and 13C NMR spectroscopy and single-crystal X-ray diffraction. X-ray crystallographic analysis revealed that 1 adopts a unique trimeric aggregation state consisting of six-coordinate magnesium centers. Substitution of the ligand backbone resulted in the formation of the monomeric species 2 and 3. X-ray crystallographic analyses revealed 2 as a five-coordinate, distorted square-pyramidal magnesium complex and 3 as a four-coordinate, distorted tetrahedral species. Inspection of the metrical parameters in 1-3 indicates a decrease in the Mg-O and Mg-N bond lengths and an increase in the N-Mg-O bite angle with a decreasing coordination number at magnesium. A series of bis(salicylaldiminato)magnesium complexes have been synthesized and characterized in the solid state. Substitution of the ligand backbone was found to influence both the aggregation and the magnesium coordination state in these complexes. Copyright © 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

High-Throughput Assessment of Structural Continuity in Biologics

We demonstrate a high-throughput chemoprinting platform that confirms the consistency in the higher-order structure of protein biologics and is sensitive enough to detect single-point mutations. This method addresses the quality and consistency of the tertiary and quaternary structure of biologic drug products, which is arguably the most important, yet rarely examined, parameter. The method described uses specific small-molecule ligands as molecular probes to assess protein structure. Each library of probe molecules provides a “fingerprint” when taken holistically. After proof-of-concept experiments involving enzymes and antibodies, we were able to detect minor conformational perturbations between four 48 kDa protein mutants that only differ by one amino acid residue