BackgroundThe present study was conducted to investigate the possible association between gut microbes and immunity among healthy middle-aged and elderly individuals in southwest China. A total of 148 healthy adults aged ≥ 50 years were divided into two age groups: middle-aged group (50–59 years; n = 67, 54.13 ± 3.32) and elderly group (≥ 60 years; n = 81, 64.70 ± 3.93). Blood samples were collected to measure serum immune and biochemical indices. Gut microbiota compositions of the groups were characterized on the basis of faecal DNA using 16S rRNA gene sequencing.ResultsAmong the detected gut microbes, the presence of Alistipes was negatively correlated with age in both groups. In the middle-aged group, age was negatively correlated with the presence of Desulfovibrio and Faecalibacterium. In the elderly group, Coprococcus was present at significantly higher levels; age was negatively correlated with the presence of Lachnobacterium, Oxalobacter and the Chao index, whereas positively correlated with the presence of Sutterella. In the middle-aged group, the presence of Bacteroidetes was positively correlated with serum immunoglobulin G (IgG) levels and the percent of CD8+ T cells and negatively correlated with the CD4+/CD8+ ratio; the presence of Firmicutes was negatively correlated with IgM levels; Bacteroidetes/Firmicutes ratio was positively correlated with IgG and IgM levels and Simpson index was negatively correlated with the percent of CD8+ T cells and positively correlated with CD4+/CD8+ ratio. In the elderly group, the presence of Verrucomicrobia (identified as genus Akkermansia) was positively correlated with IgA levels and the percent of CD8+ T cells and negatively correlated with the percent of CD4+ T cells and CD4+/CD8+ ratio; the Chao index and observed species were positively correlated with IgA levels.ConclusionsThese results indicated that ageing could significantly correlate with the composition of gut microbiota in terms of quantity and quality. Changes in gut microbiota caused by ageing, characterized by decreased Bacteroidetes levels, might be associated with immunosenescence among healthy middle-aged and elderly people in southwest China.Electronic supplementary materialThe online version of this article (10.1186/s13099-018-0231-3) contains supplementary material, which is available to authorized users.

The substitution patterns in fluorinated tetraphenylethenes affect the emission properties, mechano- and thermofluorochromism, compared to those of the parent TPE.

Path‐guided wrinkling enables fabrication of defect‐free and arbitrary‐shaped wrinkle patterns. A new concept of unit‐wrinkle is introduced here, through which more complex wrinkle patterns can be quantitatively designed and realized by the processes of laser direct writing‐guided wrinkling. A simulation based on a composite film model agrees remarkably well with experimental data. Wavy‐surfaced devices are able to be produced by path‐guided wrinkling.

New anhydrous lanthanide metal-organic frameworks (MOFs) [Pr(tip)1.5]2n (tip-Pr), [Nd(tip)1.5]2n (tip-Nd), [Eu-(tip)1.5]2n (tip-Eu), and [Eu(OH)(mip)]n (mip-Eu) (tip=5-tert-butylisophthalate anion, mip=5-methylisophthalate ion), have been hydrothermally synthesized and structurally characterized by elemental analyses, FT-IR spectroscopy, single-crystal X-ray diffraction, thermal gravimetric analysis/differential thermal analysis (TG/DTA), and X-ray powder diffraction (XRPD) techniques. MOFs tip-Pr, tip-Nd, and tip-Eu are isostructural anhydrous compounds, and exhibit an unprecedented 3D microporous structure with hexagonal channel arrays. The selectively prepared MOF mip-Eu presents an interpenetrated 3D microporous architecture containing the hydroxyl cluster chains. Solid-state photoluminescence properties at room temperature indicate that both tip-Eu and mip-Eu display the characteristic of the Eu3+ ion spectrum dominated by the 5D0-->7F(J) (J=0-4) transition. Compared with mip-Eu, tip-Eu displays the very high solid-state quantum yield (0.62 ± 0.03) and longer lifetime value (0.94 ± 0.01 ms), which is due to the absence of the hydroxyl groups from the solid-state structure of tip-Eu. More importantly, a new method to directly investigate the potential of solid-state lanthanide MOFs for ionic sensing in aqueous solutions has been developed, and successfully applied it to study the potential sensing function of tip-Eu for polyoxometalates (POMs). The possible mechanism for the quenching effect of POMs on the fluorescence of tip-Eu is elucidated by the strongly competitive absorption of the excited light source energy between POMs and tip ligands. The very promise for the highly sensitive sensing for polyoxometalates, together with the characteristic of the reversible fluorescence response, suggest that solid-state tip-Eu can be an excellent candidate for the directly photoluminescent detection of POMs in aqueous solutions.

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