Soil biofilms:microbial interactions,challenges,and advanced techniques for ex-situ characterization

Soil is inhabited by a myriad of microorganisms,many of which can form supracellular structures,called biofilms,comprised of surface-associated microbial cells embedded in hydrated extracellular polymeric substance that facilitates adhesion and survival.Biofilms enable intensive inter-and intra-species interactions that can increase the degradation efficiency of soil organic matter and materials commonly regarded as toxins.Here,we first discuss organization,dynamics and properties of soil biofilms in the context of traditional approaches to probe the soil microbiome.Social interactions among bacteria,such as cooperation and competition,are discussed.We also summarize different biofilm cultivation devices in combination with optics and fluorescence microscopes as well as sequencing techniques for the study of soil biofilms.Microfluidic platforms,which can be applied to mimic the complex soil environment and study microbial behaviors at the microscale with highthroughput screening and novel measurements,are also highlighted.This review aims to highlight soil biofilm research in order to expand the current limited knowledge about soil microbiomes which until now has mostly ignored biofilms as a dominant growth form.

Cell softness reveals tumorigenic potential via ITGB8/AKT/glycolysis signaling in a mice model of orthotopic bladder cancer

Background:Bladder cancer,characterized by a high potential of tumor recurrence,has high lifelong monitoring and treatment costs.To date,tumor cells with intrinsic softness have been identified to function as cancer stem cells in several cancer types.Nonetheless,the existence of soft tumor cells in bladder tumors remains elusive.Thus,our study aimed to develop a microbarrier microfluidic chip to efficiently isolate deformable tumor cells from distinct types of bladder cancer cells.Methods:The stiffness of bladder cancer cells was determined by atomic force microscopy(AFM).The modified microfluidic chip was utilized to separate soft cells,and the 3D Matrigel culture system was to maintain the softness of tumor cells.Expression patterns of integrinβ8(ITGB8),protein kinase B(AKT),and mammalian target of rapamycin(mTOR)were determined by Western blotting.Double immunostaining was conducted to examine the interaction between F-actin and tripartite motif containing 59(TRIM59).The stem-cell-like characteristics of soft cells were explored by colony formation assay and in vivo studies upon xenografted tumor models.Results:Using our newly designed microfluidic approach,we identified a small fraction of soft tumor cells in bladder cancer cells.More importantly,the existence of soft tumor cells was confirmed in clinical human bladder cancer specimens,in which the number of soft tumor cells was associated with tumor relapse.Furthermore,we demonstrated that the biomechanical stimuli arising from 3D Matrigel activated the F-actin/ITGB8/TRIM59/AKT/mTOR/glycolysis pathways to enhance the softness and tumorigenic capacity of tumor cells.Simultaneously,we detected a remarkable up-regulation in ITGB8,TRIM59,and phospho-AKT in clinical bladder recurrent tumors compared with their non-recurrent counterparts.Conclusions:The ITGB8/TRIM59/AKT/mTOR/glycolysis axis plays a crucial role in modulating tumor softness and stemness.Meanwhile,the soft tumor cells become more sensitive to chemotherapy after stiffening,that offers new insights for hampering tumor progression and recurrence.