98%
921
2 minutes
20
Sugar maples (Acer saccharum Marshall) develop elevated stem pressures in springtime through the compression and expansion of gas bubbles present within xylem fibres. The stability of this gas within the fibres is hypothesised to be due to the elevated sugar concentration of maple sap and the presence of an osmotic barrier between fibres and vessels. Without this osmotic barrier gas bubbles are predicted to dissolve rapidly. In this work we investigated the existence of this osmotic barrier. We quantified the fraction of the xylem occupied by gas-filled fibres using synchrotron based microCT. After imaging fresh stem segments we perfused them with either a 2% sucrose solution or water, imaging again following perfusion. In this way we directly observed how total gas present in the fibres changed when an osmotic pressure difference should be present, with the 2% sucrose solution, and when it is absent, with the water. Following a first round of perfusion we perfused stem segments with the other perfusate, repeating this multiple times to observe how switching perfusates affected gas-filled fibres. We found that perfusing stem segments with water resulted in a significant reduction in the xylem fibre gas, but perfusing stem segments with a sucrose solution did not significantly reduce the gas in the fibres. These results support the hypothesis that an osmotic barrier exists between fibres and vessels.
Download full-text PDF |
Source |
---|---|
http://dx.doi.org/10.1093/treephys/tpae134 | DOI Listing |
ACS Synth Biol
September 2025
Engineering Research Center of Western Resource Innovation Medicine Green Manufacturing, Ministry of Education, School of Chemical Engineering, Northwest University, Xi'an 710127, China.
The environmental resistance exhibited by microorganisms is concerned with their ability to withstand and adapt to an array of detrimental environmental conditions, with their survival and reproductive success being threatened. Within the realm of biotechnology, which emphasizes stress resistance, a critical role in bacterial adaptive strategies to environmental fluctuations is assumed to be in the periplasmic space. An innovative methodology to augment bacterial tolerance to stress by employing a mucin-mimetic collagen analogue, designated as S1552 (which is secreted into the periplasmic compartment), is introduced by this investigation.
View Article and Find Full Text PDFFront Biosci (Landmark Ed)
August 2025
Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy.
Background: The global increase in diabetes mellitus has been accompanied by a significant rise in related complications. Diabetic patients frequently experience ocular surface disorders and multiple studies have demonstrated that the diabetic corneal epithelium is characterized by increased cellular fragility and compromised barrier integrity. It has been demonstrated that the processes of oxidative stress and inflammation are pivotal in causing ocular tissue damage in diabetic patients.
View Article and Find Full Text PDFJ Am Chem Soc
September 2025
Key Laboratory of Functional Inorganic Materials Chemistry, Ministry of Education of the People's Republic of China, Heilongjiang University, Harbin 150080, China.
Nanofluidics-based reverse electrodialysis offers a promising approach for harnessing the osmotic energy that exists between saline and fresh water, thereby providing a sustainable source of power. Nevertheless, the key obstacle to realizing a commercially viable power output stems from inadequate ion permselectivity in nanofluidics. Here, we engineer dual asymmetric MXene-based composite nanofluidics (DA-MXCNs) composed of a negatively charged, porous MXene layer and a positively charged, confined MXene layer, which strategically incorporates asymmetric channel dimensions and opposing charge distributions.
View Article and Find Full Text PDFRadiology
September 2025
Department of Diagnostic Radiology and Nuclear Medicine, School of Medicine, University of Maryland, 670 W Baltimore St, Baltimore, MD 21201.
Background Given the current lack of widely adopted strategies for facilitating drug penetration into the brain, developing new techniques to increase blood-brain barrier (BBB) permeability is essential to address the increasing burden of central nervous system disorders. Osmotic blood-brain barrier opening (OBBBO), achieved through intra-arterial delivery of 25% mannitol to the cerebral vasculature, is a pioneering strategy demonstrating both safety and partial efficacy. Purpose To investigate the potential of 25% mannitol with 4% NaCl, a combination that doubles the osmotic power, to safely increase OBBBO efficacy.
View Article and Find Full Text PDFJ Sci Food Agric
September 2025
School of Food Science and Technology, Dalian Polytechnic University, National Engineering Research Center of Seafood, Dalian, People's Republic of China.
Background: Constipation is a frequent chronic disease in the community, and osmotic laxatives can effectively alleviate symptoms. However, it is not suitable for long-term use. Dietary fiber is an alternative option, with a capacity to address intestinal barrier dysfunction and sustained microbial dysbiosis.
View Article and Find Full Text PDF