Functional differentiation determines the molecular basis of the symbiotic lifestyle of Ca. Nanohaloarchaeota.

BACKGROUND: Candidatus Nanohaloarchaeota, an archaeal phylum within the DPANN superphylum, is characterized by limited metabolic capabilities and limited phylogenetic diversity and until recently has been considered to exclusively inhabit hypersaline environments due to an obligate association with Halobacteria. Aside from hypersaline environments, Ca. Nanohaloarchaeota can also have been discovered from deep-subsurface marine sediments. RESULTS: Three metagenome-assembled genomes (MAGs) representing a new order within the Ca. Nanohaloarchaeota were reconstructed from a stratified salt crust and proposed to represent a novel order, Nucleotidisoterales. Genomic features reveal them to be anaerobes capable of catabolizing nucleotides by coupling nucleotide salvage pathways with lower glycolysis to yield free energy. Comparative genomics demonstrated that these and other Ca. Nanohaloarchaeota inhabiting saline habitats use a "salt-in" strategy to maintain osmotic pressure based on the high proportion of acidic amino acids. In contrast, previously described Ca. Nanohaloarchaeota MAGs from geothermal environments were enriched with basic amino acids to counter heat stress. Evolutionary history reconstruction revealed that functional differentiation of energy conservation strategies drove diversification within Ca. Nanohaloarchaeota, further leading to shifts in the catabolic strategy from nucleotide degradation within deeper lineages to polysaccharide degradation within shallow lineages. CONCLUSIONS: This study provides deeper insight into the ecological functions and evolution of the expanded phylum Ca. Nanohaloarchaeota and further advances our understanding on the functional and genetic associations between potential symbionts and hosts. Video Abstract.

Studies on quality specification of Zishen Yangyin Granules / 中草药

Objective: To establish methods of qualitative identification and quantitative determination for Zishen Yangyin Granules (ZYG). Methods: The TLC method was used to identify the herb by mixture of chloroform-methanol (31) as a developing solvent on high performance silica gel precoated plate (HSGF254) and using 5% vanillic aldehyde sulfuric acid as a chromogenic reagent for qualitative identification of Corni Fructus; TLC identification of Eclipta prostrata, Alismatis Rhizoma, and Moutan Cortex was performed on high performance silica gel precoated plate (HSGF254) with petroleum ether (60-90 ℃)-chloroform-ethyl acetate (312) as developing solvent. The same developing method was used to identify E. prostrata, A. Rhizoma, and paneol in M. Cortex of ZYG by different detected method at the same time. The contents of morroniside, loganin, hyperoside, specnuezhenide, and paeonol were analyzed by high performance liquid chromatography on C18 column (250 mm × 4.6 mm, 5 μm) with the mobile phase of acetonitrile-0.1% trifluoroacetic acid by gradient elution. The detection wavelength was set at 254 nm. Results: Morroniside and loganin were used to identify C. Fructus in ZYG, paeonol in M. Cortex can be identified at 254 nm; Some substances in E. prostrata can be identified at 366 nm; Some substances in A. Rhizoma can be detected in sunlight, with 5% phosphomolybdic acid in ethanol as a chromogenic reagent. The TLC separation was desirable with moderate Rf value and clear spot. The methodology validation for the assay of morroniside, loganin, hyperoside, specnuezhenide, and paeonol presented that they were in good linear correlation in the ranges of 4.432-110.8, 4.192-104.8, 4.040-101.0, 4.132-103.3, and 4.076-101.9 μg/mL, The correlation coefficients of indicator were over 0.999 7. The average recoveries were between 96.57% and 98.67%. The RSD value of intra-day precision was less than 2% and the RSD value of inter-day precision was less than 3%. The method has good stability and reproducibility. Conclusion: The methods of quality control are specific, reproducible, accurate, and suitable, which can be successfully applied to the quality control of ZYG.