Calculations of modulus of elasticity for extended-and folded-chain configurations have been compared with the experimental observations of mechanical properties of native cellulosic fibers. A recent folded-chain proposal is incompatible with the experimental evidence.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1126/science.164.3875.72 | DOI Listing |
mSystems
February 2024
Department of Bacteriology, University of Wisconsin-Madison, Madison, Wisconsin, USA.
Disturbance events can impact ecological community dynamics. Understanding how communities respond to disturbances and how those responses can vary is a challenge in microbial ecology. In this study, we grew a previously enriched specialized microbial community on either cellulose or glucose as a sole carbon source and subjected them to one of five different disturbance regimes of varying frequencies ranging from low to high.
View Article and Find Full Text PDFPhysiol Mol Biol Plants
August 2023
California Baptist University, Riverside, CA 92504 USA.
Sucrose synthase (SUS), an enzyme that breaks down sucrose, is known to play an important role in the production of UDP-glucose and ADP-glucose. An established and highly debated theory holds that SUS is necessary for providing UDP-glucose and ADP-glucose for the biosynthesis of cellulose and starch, respectively. This article is focused on two recent reports which refuted the long-held theory that SUS is the sole regulator in cellulose and starch synthesis.
View Article and Find Full Text PDFPlant J
June 2022
Department of Forest Genetics and Plant Physiology, Umeå Plant Science Centre, Swedish University of Agricultural Sciences, SE 901 83, Umeå, Sweden.
Biosynthesis of plant cell walls requires UDP-glucose as the substrate for cellulose biosynthesis, and as an intermediate for the synthesis of other matrix polysaccharides. The sucrose cleaving enzyme sucrose synthase (SUS) is thought to have a central role in UDP-glucose biosynthesis, and a long-held and much debated hypothesis postulates that SUS is required to supply UDP-glucose to cellulose biosynthesis. To investigate the role of SUS in cellulose biosynthesis of Arabidopsis thaliana we characterized mutants in which four or all six Arabidopsis SUS genes were disrupted.
View Article and Find Full Text PDFInt J Gynaecol Obstet
October 2022
Department of Pharmacology, University of Pretoria, Pretoria, South Africa.
Objective: To assess the effects of "sperm-friendly" coital lubricants on sperm motility.
Methods: This study compared the effects of five lubricants (Optilube®, Pre-Seed®, Yes Baby®, olive oil, and egg white) on sperm motility in 60 normozoospermic semen samples obtained from men attending a private fertility clinic. Samples were exposed to each of the lubricants, with untreated samples serving as controls, and were examined microscopically at four defined time-points from 2 to 72 h after liquefaction.
J Exp Bot
June 2017
Department of Chemistry and Biochemistry, Loyola University Chicago, 1068 West Sheridan Road, 60660 Chicago, IL, USA.
Nucleoside diphosphate sugars (NDP-sugars) are the substrates for biosynthesis of oligo- and polysaccharides, such as starch and cellulose, and are also required for biosynthesis of nucleotides, ascorbic acid, several cofactors, glycoproteins and many secondary metabolites. A controversial study that questions the generally accepted pathway of ADP-glucose and starch synthesis in plants is based, in part, on claims that NDP-sugars are unstable at alkaline pH in the presence of Mg2+ and that this instability can lead to unreliable results from in vitro assays of enzyme activities. If substantiated, this claim would have far-reaching implications for many published studies that report on the activities of NDP-sugar metabolizing enzymes.
View Article and Find Full Text PDFEnter search terms and have AI summaries delivered each week - change queries or unsubscribe any time!