Desulfurization of model and diesel oils by resting cells of Gordona sp.

The desulfurization activity of the resting cells of Gordona sp. CYKS1 was strongly depended on harvest time and the highest value when the cells had been harvested in the early growth phase (0.12 mg sulfur g^–1 cell^–1 h^–1). For the model oil, hexadecane containing dibenzothiophene, the specific desulfurization rate decreased as the reaction proceeded. Both the specific and the volumetric desulfurization rates were not significantly affected by the aqueous-to-oil phase ratio. The diesel oils, light gas oil and a middle distillate unit feed were desulfurized at higher rates (ca. 0.34 mg sulfur g^–1 cell^–1 h^–1) than the model oil (0.12 mg sulfur g^–1 cell^–1 h^–1).     

A cross-talk between epithelium and endothelium mediates human alveolar–capillary injury during SARS-CoV-2 infection

COVID-19, caused by SARS-CoV-2, is an acute and rapidly developing pandemic, which leads to a global health crisis. SARS-CoV-2 primarily attacks human alveoli and causes severe lung infection and damage. To better understand the molecular basis of this disease, we sought to characterize the responses of alveolar epithelium and its adjacent microvascular endothelium to viral infection under a co-culture system. SARS-CoV-2 infection caused massive virus replication and dramatic organelles remodeling in alveolar epithelial cells, alone. While, viral infection affected endothelial cells in an indirect manner, which was mediated by infected alveolar epithelium. Proteomics analysis and TEM examinations showed viral infection caused global proteomic modulations and marked ultrastructural changes in both epithelial cells and endothelial cells under the co-culture system. In particular, viral infection elicited global protein changes and structural reorganizations across many sub-cellular compartments in epithelial cells. Among the affected organelles, mitochondrion seems to be a primary target organelle. Besides, according to EM and proteomic results, we identified Daurisoline, a potent autophagy inhibitor, could inhibit virus replication effectively in host cells. Collectively, our study revealed an unrecognized cross-talk between epithelium and endothelium, which contributed to alveolar–capillary injury during SARS-CoV-2 infection. These new findings will expand our understanding of COVID-19 and may also be helpful for targeted drug development.Subject terms: Mechanisms of disease, Viral infection     

Selection and proliferation of rapid growing cell lines from embryo derived cell cultures of yew tree (Taxus cuspidata Sieb. et Zucc)

Calli were induced from 300,000 embryos isolated from immature to mature stage of seeds collected on late September from 14 elite trees. When the embryos were cultured onto plastic Petri-dish containing 20 mL of modified B5 basal medium supplemented with 3% (w/v) sucrose, 500 mg/L casein hydrolysate, 250 mg/L myo-inositol, 0.5% (w/v) polyvinyl polypyrrolidon (PVPP), 2×MS vitamins, 0.5 mg/L gibberellic acid, and 10 mg/L 2,4-D after 2 weeks of culture, yellowish-white calli were immediately formed on the surfaces of embryos, and subcultured for 4 weeks in same culture medium. Because most of calli maintained for more than 3 months were revealed differences in their colors, surface texture, and growth rate, visual selection was made for first round screening. When the size of visually selected calli larger than 19 mm in their diameter were inoculated, persistent proliferation was observed. Among the plating methods tested for the selection of rapid growing cell lines at single cell and/or small cell aggregate level, 2-layer spread plating revealed as the best for single cell cloning. To enhance cell growth and maintain high rate of viability for long-term culture of yew cells in bioreactor, final cell volume less than 50% in SCV seemed to be the best. Time course study revealed that 30% of inoculum density was suitable for fed batch culture. Among the tested conditional media, the rate of 1∶2 (old medium: fresh medium) was recorded at the best for cell growth.     

Modulation of Intracellular Calcium Levels by Calcium Lactate Affects Colon Cancer Cell Motility through Calcium-Dependent Calpain

Cancer cell motility is a key phenomenon regulating invasion and metastasis. Focal adhesion kinase (FAK) plays a major role in cellular adhesion and metastasis of various cancers. The relationship between dietary supplementation of calcium and colon cancer has been extensively investigated. However, the effect of calcium (Ca²⁺) supplementation on calpain-FAK-motility is not clearly understood. We sought to identify the mechanism of FAK cleavage through Ca²⁺ bound lactate (CaLa), its downstream signaling and role in the motility of human colon cancer cells. We found that treating HCT116 and HT-29 cells with CaLa immediately increased the intracellular Ca²⁺ (iCa²⁺) levels for a prolonged period of time. Ca²⁺ influx induced cleavage of FAK into an N-terminal FAK (FERM domain) in a dose-dependent manner. Phosphorylated FAK (p-FAK) was also cleaved in to its p-N-terminal FAK. CaLa increased colon cancer cells motility. Calpeptin, a calpain inhibitor, reversed the effects of CaLa on FAK and pFAK cleavage in both cancer cell lines. The cleaved FAK translocates into the nucleus and modulates p53 stability through MDM2-associated ubiquitination. CaLa-induced Ca²⁺ influx increased the motility of colon cancer cells was mediated by calpain activity through FAK and pFAK protein destabilization. In conclusion, these results suggest that careful consideration may be given in deciding dietary Ca²⁺ supplementation to patient undergoing treatment for metastatic cancer.     

Microstructures in the Organ of Corti Help Outer Hair Cells Form Traveling Waves along the Cochlear Coil

According to the generally accepted theory of mammalian cochlear mechanics, the fluid in the cochlear scalae interacts with the elastic cochlear partition to generate transversely oscillating displacement waves that propagate along the cochlear coil. Using a computational model of cochlear segments, a different type of propagating wave is reported, an elastic propagating wave that is independent of the fluid-structure interaction. The characteristics of the propagating wave observed in the model, such as the wavelength, speed, and phase lag, are similar to those observed in the living cochlea. Three conditions are required for the existence of the elastic propagating wave in the cochlear partition without fluid-interaction: 1), the stiffness gradient of the cochlear partition; 2), the elastic longitudinal coupling; and 3), the Y-shaped structure in the organ of Corti formed by the outer hair cell, the Deiters cell, and the Deiters cell phalangeal process. The elastic propagating waves in the cochlear partition disappeared without the push-pull action provided by the outer hair cell and Deiters cell phalangeal process. The results suggest that the mechanical feedback of outer hair cells, facilitated by the organ of Corti microstructure, can control the tuning and amplification by modulating the cochlear traveling wave.