Herawati et al. developed a long-term and high-resolution live imaging system for cultured mouse tracheal multiciliated cells. Using both experimental and theoretical studies, they reveal the developmental principle of ciliary basal body alignment directed by apical cytoskeletons.

Gram-positive bacteria of the genus Streptomyces are industrially important microorganisms, producing >70% of commercially important antibiotics. The production of these compounds is often regulated by low-molecular-weight bacterial hormones called autoregulators. Although 60% of Streptomyces strains may use γ-butyrolactone–type molecules as autoregulators and some use furan-type molecules, little is known about the signaling molecules used to regulate antibiotic production in many other members of this genus. Here, we purified a signaling molecule (avenolide) from Streptomyces avermitilis —the producer of the important anthelmintic agent avermectin with annual world sales of $850 million—and determined its structure, including stereochemistry, by spectroscopic analysis and chemical synthesis as (4 S ,10 R )-10-hydroxy-10-methyl-9-oxo-dodec-2-en-1,4-olide, a class of Streptomyces autoregulator. Avenolide is essential for eliciting avermectin production and is effective at nanomolar concentrations with a minimum effective concentration of 4 nM. The aco gene of S. avermitilis, which encodes an acyl-CoA oxidase, is required for avenolide biosynthesis, and homologs are also present in Streptomyces fradiae , Streptomyces ghanaensis , and Streptomyces griseoauranticus , suggesting that butenolide-type autoregulators may represent a widespread and another class of Streptomyces autoregulator involved in regulating antibiotic production.

Abstract. Herawati E, Ramadhan R, Ariyani F, Marjenah, Kusuma IW, Suwinarti W, Mardji D, Amirta R, Arung ET. 2021. Phytochemical screening and antioxidant activity of wild mushrooms growing in tropical regions. Biodiversitas 22: 4716-4721. This study aims to determine the presence of secondary metabolites which generally have bioactivity that is antioxidant with phytochemical tests and antioxidant tests in Auricularia auricula, Schyzophyllum commune, Microporus xanthopus, and Trametes versicolor fungi that grow in the wild. Phytochemical analysis was carried out by testing color changes and modifications, while antioxidant tests were carried out by using a UV-Vis spectrophotometer and a DPPH solution (1,1-diphenyl-2-picrylhydrazyl). This research found that edible wood fungus that grows, wild such as A. auricula, contains secondary metabolites, namely flavonoids, triterpenoids, saponins, and tannins, but does not contain steroids, alkaloids, carotenoids, or coumarin, while S. commune contains secondary metabolites, namely flavonoids, steroids, tannins, and coumarin, but does not contain triterpenoids, alkaloids, carotenoids, or saponins and non-edible wood fungus, such as M. xanthopus, contains secondary metabolites, namely, flavonoids, saponins, tannins, coumarin, and steroids, but does not contain triterpenoids, alkaloids, or carotenoids, while T. versicolor contains compounds, secondary metabolites, flavonoids, saponin, tannins, coumarin, and triterpenoids, but does not contain steroids, alkaloids, or carotenoids. The antioxidant test results are based on IC50 calculations; it is known that the IC50 value of A. auricula is 499.25 g/mL, while S. commune is 121.37 g/mL, M. xanthopus is 251.20 g/mL, and T. versicolor is 493.04 g/mL. Based on the research results, edible and inedible wood mushroom extracts contain several phytochemicals and show potential for antioxidant activity.

Multiciliated cells (MCCs) in tracheas generate mucociliary clearance through coordinated ciliary beating. Apical microtubules (MTs) play a crucial role in this process by organizing the planar cell polarity (PCP)–dependent orientation of ciliary basal bodies (BBs), for which the underlying molecular basis remains elusive. Herein, we found that the deficiency of Daple, a dishevelled-associating protein, in tracheal MCCs impaired the planar polarized apical MTs without affecting the core PCP proteins, causing significant defects in the BB orientation at the cell level but not the tissue level. Using live-cell imaging and ultra-high voltage electron microscope tomography, we found that the apical MTs accumulated and were stabilized by side-by-side association with one side of the apical junctional complex, to which Daple was localized. In vitro binding and single-molecule imaging revealed that Daple directly bound to, bundled, and stabilized MTs through its dimerization. These features convey a PCP-related molecular basis for the polarization of apical MTs, which coordinate ciliary beating in tracheal MCCs.