Department of Molecular and Cellular Biology, Harvard University, Cambridge, MA 02138, USA.
Published: March 2020
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Article Abstract
The gliding bacterium is known to have an adhesin, SprB, that moves along the cell surface on a spiral track. Following viscous shear, cells can be tethered by the addition of an anti-SprB antibody, causing spinning at 3 Hz. Labeling the type 9 secretion system (T9SS) with a YFP fusion of GldL showed a yellow fluorescent spot near the rotation axis, indicating that the motor driving the motion is associated with the T9SS. The distance between the rotation axis and the track (90 nm) was determined after adding a Cy3 label for SprB. A rotary motor spinning a pinion of radius 90 nm at 3 Hz would cause a spot on its periphery to move at 1.5 μm/s, the gliding speed. We suggest the pinion drives a flexible tread that carries SprB along a track fixed to the cell surface. Cells glide when this adhesin adheres to the solid substratum.
One of the major age-related declines in female reproductive function is the reduced quantity and quality of oocytes. Here we demonstrate that structural changes in the zona pellucida (ZP) were associated with decreased fertilization rates from 34- to 38-week-old female mice, equivalent to the mid-reproductive of human females. In middle-aged mouse ovaries, the decline in the number of transzonal projections was accompanied by a decrease in cumulus cell-oocyte interactions, resulting in a deterioration of the oocyte quality.
The present study introduces a minimalistic and cost-effective approach to synthesising Gold nanoparticles (AuNPs) using aqueous leaf extracts of Andrographis paniculata. In this synthesis, bioactive metabolites in the leaf extract act as reducing agents, converting Au³⁺ ions to metallic Au⁰, while proteins in the extract form a stabilising layer around the nanoparticles to prevent agglomeration and maintain particle size stability. The synthesised AuNPs were systematically characterised using a range of analytical techniques.
Cellular mechanical dysregulation can lead to diseases and conditions like tumorigenesis. Drug delivery systems that recognize and respond to specific cellular mechanical characteristics are potentially useful for targeted therapy. We report here the creation of a DNA mechanical nanovehicle that is responsive to cell surface receptor-mediated tensile forces, which can then correspondingly deliver an anticancer drug in situ.
Ethnopharmacological Relevance: Acne vulgaris is a common skin disease affecting the pilosebaceous unit, in which abnormal sebum secretion and inflammation play crucial roles. The traditional Chinese medicine Tanreqing has been utilized in dermatology to effectively treat various diseases. However, its effects and underlying mechanisms in acne vulgaris remain unclear.
Cancer Center and Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee, Wisconsin 53226, United States. Electronic address:
G protein-coupled receptors (GPCRs) are the largest family of cell surface receptors in humans, playing a crucial role in regulating diverse cellular processes and serving as primary drug targets. Traditional drug design has primarily focused on ligands that uniformly activate or inhibit GPCRs. However, the concept of biased agonism-where ligands selectively stabilize distinct receptor conformations, leading to unique signaling outcomes-has introduced a paradigm shift in therapeutic development.
