Floating Mat Formation Makes Zizania latifolia More Competitive under the Conditions of Continuous Significant Water Level Rise.

Water level rise is considered an environmental filter for the growth and reproduction of aquatic plants in lakes. Some emergent macrophytes can form floating mats, enabling them to escape from the negative effects of deep water. However, an understanding of which species can be uprooted and form floating mats easily and what factors affect these tendencies remains greatly elusive. We conducted an experiment to determine whether the monodominance of Zizania latifolia in the emergent vegetation community in Lake Erhai was related to its floating mat formation ability and to try to find the reasons for its floating mat formation ability during the continuous increase in water level over the past few decades. Our results showed that both the frequency and biomass proportion of Z. latifolia were greater among the plants on the floating mats. Furthermore, Z. latifolia was more likely to be uprooted than the other three previously dominant emergent species due to its smaller angle between the plant and the horizontal plane, rather than the root:shoot or volume:mass ratios. The dominance of Z. latifolia in the emergent community in Lake Erhai is due to its easier ability to become uprooted, allowing it to outperform other emergent species and become the single dominant emergent species under the environmental filter of deep water. The ability to uproot and form floating mats may be a competitive survival strategy for emergent species under the conditions of continuous significant water level rise.

A simple method for in vitro preparation of natural killer cells from cord blood.

BACKGROUND: Cord Blood (CB) has been considered a promising source of natural killer (NK) cells for cellular immunotherapy. However, it is difficult to expand the large numbers of highly pure NK cells from CB without cell sorting and feeder cells/multiple cytokines. In this study, we try to develop a simple, safe and economical method for ex vivo expansion and purification of NK cells from CB without cell sorting and feeder cells/multiple cytokines. RESULTS: The large numbers (mean: 1.59 × 1010) of highly pure (≥90%) NK cells from CB could be obtained through interleukin-2, group A streptococcus and zoledronate stimulation of mononuclear cells using the 21-day culture approach. When compared to resting NK cells, expanded NK cells were a higher expression of activating receptors CD16, NKG2D, NKp30, NKp44, NKp46 and activating markers CD62L and CD69, while the inhibitory receptors, CD158a and CD158b remained largely unchanged. In addition, these cells showed a higher concentration of IFN-γ, TNF-α and GM-CSF secretion and cytotoxicity to K562 cells and acute myeloid leukemia targets than resting NK cells. CONCLUSION: We develop a simple, safe and economical method to obtain high yield, purity, and functionality NK cells from CB without cell sorting and feeder cells/multiple cytokines.

Immunosuppressive Effect of Exosomes from Mesenchymal Stromal Cells in Defined Medium on Experimental Colitis.

BACKGROUND AND OBJECTIVES: The exosomes released by mesenchymal stromal cells (MSCs) in classical FBS-containing media have been demonstrated as an alternative, cell-free therapy in various diseases including inflammatory bowel disease (IBD). It has been found that the function of exosomes is affected by culture condition. We previously developed a serum-free, xeno-free and chemically defined medium, and umbilical cord-derived MSCs in this medium retained the immunosuppressive capability. METHODS: In this study, we evaluated the immunosuppressive function of exosomes from MSCs (MSC-Exo) in defined medium and their therapeutic effect on treating colitis. RESULTS AND CONCLUSIONS: In vitro studies indicated that MSC-Exo reduced the concentration of pro-inflammatory cytokines IFN-γ, TNF-α and IL-1ß, and increased the secretion of anti-inflammatory cytokines TGF-ß1 and IL-10, but no significant change of inhibitory effect on peripheral blood mononuclear cells proliferation was shown. In vivo experimental colitis showed that administration of MSC-Exo was able to significantly ameliorate the disease activity index score, weight loss, colon shortening, and the histological colitis score through up-regulation anti-inflammatory responses and down-regulation of inflammatory responses. Moreover, the use of MSC-Exo (200 µg) led to an improved therapeutic efficacy when compared with MSCs at a dose of 1×106 cells. Our findings indicate that the exosomes from MSCs in defined medium possess a certain degree of immunosuppressive effect in vitro and exhibit a therapeutic capability in a mouse model of DSS-induced colitis through suppressing inflammation mechanism.