Arbuscular Mycorrhizal Fungi Alleviates Salt-Alkali Stress Demage on Syneilesis aconitifolia

Syneilesis aconitifolia is a potential ground cover and decorative material in gardens,which exhibits a strong salt-alkali tolerance,and also has medicinal value.In this study,the arbuscular mycorrhizal(AM)fungi community in the soil surrounding S.aconitifolia roots in the Songnen saline-alkali grassland was used as the inoculation medium for a pot cultivation experiment.After normal culture for 90 days,NaCl and NaHCO_(3) solutions were applied to subject plants to salt or alkali stress.Solution concentrations of 50,100,and 200 mmol/L were applied for 10 days,and mycorrhizal colonization,biomass,relative water content(RWC),chlorophyll concentration,malondialdehyde(MDA)concentration,antioxidant system activity,and osmomodulator concentration were determined to identify the effects of AM fungi on root colonization status and salinity tolerance in S.aconitifolia.There were three key results.(1)Compared to the controls,the intensity and rate of colonization decreased under saline-alkali stress,and the adaptability of AM fungi under low concentration alkali stress was higher than that under salt stress.(2)The AM fungi could increase the biomass,RWC,and chlorophyll concentration,and decrease the MDA concentration of S.aconitifolia to some extent.With an increase in the salt or alkali solution concentration,AM fungi not only upregulated the activity of the antioxidant system,but also increased the concentration of osmotic regulatory substances.(3)A multivariate analysis of variance(ANOVA)and radar map analysis showed that the mechanisms of resistance to salt and alkali stress were not the same in S.aconitifolia.In the salt treatment,AM fungi mainly regulated salt stress through osmotic regulatory substances such as soluble sugars,soluble proteins,and proline.In the alkali treatment,AM fungi mainly regulated alkali stress through glutathione(GSH),soluble sugars,and MDA.The results showed that the colonization rate of S.aconitifolia under low concentration alkali stress was higher than that under salt stress,and the inoculation of AM fungi could significantly reduce the MDA concentration of S.aconitifolia plants under salinity and alkali stress,and improve the antioxidant enzyme activity and osmoregulatory substance accumulation,thereby improving the salinity tolerance of S.aconitifolia.

Versatile metal graphitic nanocapsules for SERS bioanalysis

The novel graphitic nanomaterial of metal graphitic nanocapsules(MGNs) with superior stability, unique optical properties and biocompatibility possess great potential in biomedical and bioanalytical applications. The graphitic shell can quench the background fluorescence interference from external environments via a fluorescence resonance energy transfer(FRET) process and even avoid unnecessary reactions catalyzed by inner metal core. The graphitic shell with several characteristic Raman bands itself can act as Raman signal probe or internal standard(IS), especially the 2D-band within the cellular Raman-silent region helps to reduce the interference signals from external conditions. The present context attempts to give a comprehensive overview about the preparation and unique properties of MGNs as well as their applications in SERS biodetection and bioimaging.

Zinc-substituted hemoglobin with specific drug binding sites and fatty acid resistance ability for enhanced photodynamic therapy

Precisely designed protein-based nanodrugs, as a kind of colloidal drug system, have attracted significant attention in tumor therapy because of their refined drug loading ratio, controlled delivery efficacy and natural biocompatibility. However, most drugs are conjugated to the protein carriers randomly without specific binding sites. Moreover, such sites could easily be replaced by lipophilic molecules in the physiological environment and result in low delivery efficiency. With strong and specific binding locations especially comparatively narrow spatial binding sites and nonflexible structure, hemin (FePPIX)-free hemoglobin or apohemoglobin (apoHb), as a natural metalloporphyrin protein carrier, represents great potential in bioapplication. Therefore, we herein introduce a folate acid (FA) modified, zinc-substituted hemoglobin (ZnPHb-FA) as a naturally occurring protein matrix-based photosensitizer for cancer photodynamic therapy (PDT). Noncovalent inserted ZnPPIX molecules in apoHb possess an extremely stable property and significant recovered photoproperties with superior biocompatibility and phototoxicity, both in vitro and in vivo. This stability was verified by molecular docking analysis and calculation of binding constant, representing a total of five drug binding sites of apoHb for ZnPPIX molecules, four of which are energetically favorable (△G value of -11.9 kcal/mol), and one which is energetically acceptable (△G value of -9 kcal/mol). Folate acid modification has been shown to efficiently enhance the internalization and retention time of ZnPHb nanodrug. ZnPHb-FA is also an efficient depressor of hemin oxygenase-1 (HO-1), which could, in turn, lower the antioxidant ability of cancer cells by decreasing the production of biiirublin. Results in vitro and in vivo both indicated that the firmly combination of apoHb and ZnPPIX described here represents a novel and efficient protein nanodrug systems for cancer therapy.