Fluorine materials scavenge excess carbon dioxide and promote Escherichia coli growth.

Fluorinated solvents have been used as oxygen carriers in closed microbial cultures to sustain aerobic conditions. However, the growth-promoting effects of fluorinated solvents remain unclear. Therefore, this study aimed to elucidate the mechanism by which fluorinated solvents promote microbial growth and to explore alternative materials that can be easily isolated after culture. Escherichia coli and HFE-7200, a fluorinated solvent, were used to explore factors other than oxygen released by fluorinated solvents that promote microbial growth. E. coli growth was promoted in gas-permeable cultures, and HFE-7200 alleviated medium acidification. Gas chromatography confirmed that HFE-7200 functioned as a scavenger of carbon dioxide produced by E. coli metabolism. Because fluorinated solvents can dissolve various gases, they could scavenge metabolically produced toxic gases from microbial cultures. Furthermore, using polytetrafluoroethylene, a solid fluorine material, results in enhanced bacterial growth. Such solid materials can be easily isolated and reused for microbial culture, suggesting their potential as valuable technologies in food production and biotechnology.

Near-field sensor array with 65-GHz CMOS oscillators can rapidly and comprehensively evaluate drug susceptibility of Mycobacterium.

Multidrug-resistant tuberculosis (MDR-TB) is a major clinical problem. Because Mycobacterium, the causative agent of tuberculosis, are slow-growing bacteria, it takes 6-8 weeks to complete drug susceptibility testing, and this delay contributes to the development of MDR-TB. Real-time drug resistance monitoring technology would be effective for suppressing the development of MDR-TB. In the electromagnetic frequency from GHz to THz regions, the spectrum of the dielectric response of biological samples has a high dielectric constant owing to the relaxation of the orientation of the overwhelmingly contained water molecule network. By measuring the change in dielectric constant in this frequency band in a micro-liquid culture of Mycobacterium, the growth ability can be detected from the quantitative fluctuation of bulk water. The 65-GHz near-field sensor array enables a real-time assessment of the drug susceptibility and growth ability of Mycobacterium bovis (BCG). We propose the application of this technology as a potential new method for MDR-TB testing.

THz irradiation inhibits cell division by affecting actin dynamics.

Biological phenomena induced by terahertz (THz) irradiation are described in recent reports, but underlying mechanisms, structural and dynamical change of specific molecules are still unclear. In this paper, we performed time-lapse morphological analysis of human cells and found that THz irradiation halts cell division at cytokinesis. At the end of cytokinesis, the contractile ring, which consists of filamentous actin (F-actin), needs to disappear; however, it remained for 1 hour under THz irradiation. Induction of the functional structures of F-actin was also observed in interphase cells. Similar phenomena were also observed under chemical treatment (jasplakinolide), indicating that THz irradiation assists actin polymerization. We previously reported that THz irradiation enhances the polymerization of purified actin in vitro; our current work shows that it increases cytoplasmic F-actin in vivo. Thus, we identified one of the key biomechanisms affected by THz waves.