Immobilized microalgae: principles, processes and its applications in wastewater treatment

Microalgae have emerged as potential candidates for biomass production and pollutant removal. However, expensive biomass harvesting, insufficient biomass productivity, and low energy intensity limit the large-scale production of microalgae. To break through these bottlenecks, a novel technology of immobilized microalgae culture coupled with wastewater treatment has received increasing attention in recent years. In this review, the characteristics of two immobilized microalgae culture technologies are first presented and then their mechanisms are discussed in terms of biofilm formation theories, including thermodynamic theory, Derjaguin-Landau-Verwei-Overbeek theory (DLVO) and its extended theory (xDLVO), as well as ionic cross-linking mechanisms in the process of microalgae encapsulated in alginate. The main factors (algal strains, carriers, and culture conditions) affecting the growth of microalgae are also discussed. It is also summarized that immobilized microalgae show considerable potential for nitrogen and phosphorus removal, heavy metal removal, pesticide and antibiotic removal in wastewater treatment. The role of bacteria in the cultivation of microalgae by immobilization techniques and their application in wastewater treatment are clarified. This is economically feasible and technically superior. The problems and challenges faced by immobilized microalgae are finally presented.

Research progress of neural stem cells as a source of dopaminergic neurons for cell therapy in Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease, the most characteristic pathological feature is the progressive loss of dopaminergic (DA) neurons in the substantia nigra pars compactus (SNpc) of the mesencephalon, along with reduced dopamine content in the striatum. Researchers have been searching for drugs and therapies to treat PD in decades. However, no approach could stop the progression of the disease, and even some of them caused adverse clinical side effects. PD has a well-defined lesion. Therefore, it is considered to be one of the most curable central nervous system diseases by cell replacement treatment. Fetal ventral mesencephalic tissue transplantation has been used to treat patients with PD and obtained positive treatment results. However, ethical issues, such as limited donor tissue, and side effects including graft-induced dyskinesias, limit its clinical applications. Neural stem cell (NSC) transplantation is a viable therapy choice because it possesses multipotency, self-renewal ability, and differentiation into DA neurons, which may substitute for lost DA neurons and slow down the neurodegenerative process in PD. Studies that investigated the delivery of NSCs by using animal models of PD revealed survival, migration, and even amelioration of behavioral deficits. Here, the research progress of NSCs or NSC-derived DA neurons in treating PD was reviewed, and the practicability of present manufacturing processes for clinical testing was considered. This review is expected to offer ideas for practical strategies to solve the present technical and biological problems related to the clinical application of NSCs in PD.

FGL1 Promotes Tumor Immune Escape in Stomach Adenocarcinoma via the Notch Signaling Pathway

Immune escape is the major reason for immunotherapy failure in stomach adenocarcinoma (STAD). We tried to reveal the underlying mechanism of FGL1 influencing STAD in this study. Bioinformatics analyses were conducted to analyze the expression of FGL1, the signaling pathways affected by FGL1, and the relation between FGL1 and immune cell infiltration. Quantitative real-time PCR (qRT-PCR), cell counting kit-8 assay, colony formation assay, flow cytometry and Transwell assay were adopted to analyze FGL1 expression, cell viability, cell proliferation, cell apoptosis, and cell invasion, respectively. Enzyme-linked immunosorbent assay, lactate dehydrogenase method, qRT-PCR and Western blot were adopted to reveal proinflammatory cytokine expression, cytotoxicity and mRNA and protein expression of the Notch signaling-related genes, respectively, after co-culture of STAD cells and CD8+T cells. Nude mice experiment was conducted to validate the results obtained above. FGL1 expressed highly in STAD and could activate the Notch signaling pathway, and it was negatively correlated with CD8+T cell infiltration. Cell experiments confirmed that high expression of FGL1 facilitated proliferation and hindered apoptosis of STAD cells. Knockdown of FGL1 could facilitate expression of pro-inflammatory factors and the cytotoxicity of CD8+T cells in co-culture system of STAD and CD8+ T cells. Knockdown of FGL1 could suppress the expression of the Notch signaling pathway-related genes, and the addition of Notch inhibitor proved that FGL1 promoted immune escape via the Notch signaling pathway. This study investigated the influence of FGL1 on STAD immune escape and demonstrated that FGL1 inhibited CD8+ T cell activation by activating the Notch signaling pathway and thus promoted tumor immune escape in STAD, providing a new potential diagnostic marker and therapeutic target for the immunotherapy of STAD patients.

Evolutionary Diversification of Prey and Predator Species Facilitated by Asymmetric Interactions

We investigate the influence of asymmetric interactions on coevolutionary dynamics of a predator-prey system by using the theory of adaptive dynamics. We assume that the defense ability of prey and the attack ability of predators all can adaptively evolve, either caused by phenotypic plasticity or by behavioral choice, but there are certain costs in terms of their growth rate or death rate. The coevolutionary model is constructed from a deterministic approximation of random mutation-selection process. To sum up, if prey's trade-off curve is globally weakly concave, then five outcomes of coevolution are demonstrated, which depend on the intensity and shape of asymmetric predator-prey interactions and predator's trade-off shape. Firstly, we find that if there is a weakly decelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species may occur, but after branching further coevolution may lead to extinction of the predator species with a larger trait value. However, if there is a weakly accelerating cost and a weakly accelerating benefit for predator species, then evolutionary branching in the predator species is also possible and after branching the dimorphic predator can evolutionarily stably coexist with a monomorphic prey species. Secondly, if the asymmetric interactions become a little strong, then prey and predators will evolve to an evolutionarily stable equilibrium, at which they can stably coexist on a long-term timescale of evolution. Thirdly, if there is a weakly accelerating cost and a relatively strongly accelerating benefit for prey species, then evolutionary branching in the prey species is possible and the finally coevolutionary outcome contains a dimorphic prey and a monomorphic predator species. Fourthly, if the asymmetric interactions become more stronger, then predator-prey coevolution may lead to cycles in both traits and equilibrium population densities. The Red Queen dynamic is a possible outcome under asymmetric predator-prey interactions.