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This paper presents methodology, concept and results of the WateReuse Foundation project WFR – 09 – 06b when developing a high pressure membrane, reverse osmosis (RO) and nanofiltration (NF) online membrane integrity testing (MIT) technique. The use of pressure-driven membrane processes, particularly RO, has grown significantly over the past few decades in water treatment and reuse applications to safeguard water supplies against harmful pathogens and impurities. In principle, RO membranes should provide a complete physical barrier to the passage of nanosize pathogens (e.g., enteric viruses). However, in the presence of imperfections and/or membrane damage, membrane breaches as small as 20 to 30 nm can allow enteric viruses to pass through the membrane and contaminate the product water stream, thereby posing a potential health hazard that is of particular concern for potable water production. This project was focused on evaluating a pulsed-marker membrane integrity monitoring (PM-MIMo) approach for RO processes on the basis of the use of a fluorescent marker. The monitoring approach employs pulsed dosing (via a precision metering pump) of a marker into the RO feed stream coupled with online marker concentration monitoring in the RO permeate by an inline spectrofluorometer. Membrane integrity is then inferred on the basis of real-time analysis of the marker permeate time − profile concentration in response. The basic concept of the PM-MIMo approach for detecting membrane breaches was successfully demonstrated, by comparing intact and damaged membranes, in a series of experiments using a diagnostic plate-and-frame RO system and spiral-wound RO pilot system. Results of the developed technique are presented in the project report to allow the industry to consider adopting this technique for RO/NF online integrity monitoring.

This paper investigated the inhibitory effect of Sesamol (Ses) on Pestalotiopsis neglecta. The potential inhibitory mechanisms were explored by observing changes in cell morphology, measuring alterations in cell membrane-related indices, as well as energy metabolism-related indices and changes in enzyme activities related to virulence. The results show that Ses completely inhibited the growth of P. neglecta at 600 μg/mL (minimum inhibitory concentration and minimum fungicidal concentration), with an EC50 of 142 ± 13.22 μg/mL. As observed with scanning electron microscopy (SEM) and transmission electron microscopy (TEM), Ses treatment resulted in the breakage and crumpling of P. neglecta cell membrane and organelle lysis. Ergosterol content and the total lipid in P. neglecta treated with 300 μg/mL Ses was 91.52% and 54% of that in the control groups, respectively. In addition, spores were stained, increased leakage of intracellular constituents at 260 nm, and decreased extracellular pH. This suggests damage to the cell membrane integrity and permeability. Furthermore, Ses decreased the ATP levels and key enzymes in the tricarboxylic acid (TCA) cycle, indicating interference with the fungal energy metabolism. Moreover, the activities of polygalacturonase (PG) and endoglucanase (EG) of P. neglecta treated with 300 μg/mL of Ses were only 28.20% and 29.13% of that in the control groups, respectively, indicating that Ses can reduce the virulence of P. neglecta. In conclusion, our results show that Ses should be considered as a potential plant-derived fungicide due to its ability to disrupt the morphology of P. neglecta, damage cell membrane integrity and permeability in P. neglecta, interfere with energy metabolism, and reduce its virulence, ultimately affecting the fungal growth.

Most multicellular organisms are freeze sensitive, but the ability to survive freezing of the extracellular fluids evolved in several vertebrate ectotherms, some plants, and many insects. Here, we test the coupled hypotheses that are perpetuated in the literature: that irreversible denaturation of proteins and loss of biological membrane integrity are two ultimate molecular mechanisms of freezing injury in freeze-sensitive insects and that seasonally accumulated small cryoprotective molecules (CPs) stabilize proteins and membranes against injury in freeze-tolerant insects. Using the drosophilid fly, Chymomyza costata, we show that seven different soluble enzymes exhibit no or only partial loss of activity upon lethal freezing stress applied in vivo to whole freeze-sensitive larvae. In contrast, the enzymes lost activity when extracted and frozen in vitro in a diluted buffer solution. This loss of activity was fully prevented by adding low concentrations of a wide array of different compounds to the buffer, including C. costata native CPs, other metabolites, bovine serum albumin (BSA), and even the biologically inert artificial compounds HistoDenz and Ficoll. Next, we show that fat body plasma membranes lose integrity when frozen in vivo in freeze-sensitive but not in freeze-tolerant larvae. Freezing fat body cells in vitro, however, resulted in loss of membrane integrity in both freeze-sensitive and freeze-tolerant larvae. Different additives showed widely different capacities to protect membrane integrity when added to in vitro freezing media. A complete rescue of membrane integrity in freeze-tolerant larvae was observed with a mixture of proline, trehalose, and BSA.

The equilibration period is essential for sperm to adjust to the diluent, thereby preventing severe damage during cryopreservation. The elevation of lipid peroxidation during equilibration, indicating potential oxidative stress involvement, underscores the importance of optimizing equilibration protocols to minimize the detrimental effects of free radical production on sperm quality. This study aims to investigate the supplementation effect of adding ubiquinone to semen diluent on the membrane integrity, motility, and survivability of goat spermatozoa following an hour of equilibration. Ubiquinone supplementation was administered at varying doses: Group 2 (B) received 5 mg/dL, Group 3 (C) received 10 mg/dL, Group 4 (D) received 15 mg/dL, Group 5 (E) received 20 mg/dL, and Group 6 (F) received 25 mg/dL. Group A served as the negative control. Following one-way ANOVA examination of the research data, additional Duncan tests were conducted. The study results revealed that ubiquinone addition significantly (p<0.05) affected the percentage of motility, viability, and membrane integrity of Kacang goat spermatozoa after one hour of equilibration. According to statistical analysis, the optimal concentration of ubiquinone in egg yolk skim milk to sustain motility is 12.5 mg/dL. Conversely, the most effective concentration for preserving the viability and membrane integrity of Kacang goat spermatozoa following equilibration is 25 mg/dL. In conclusion, the addition of ubiquinone to the frozen semen diluent maintains the stability of Kacang goat spermatozoa quality after equilibration.

In this study, the role of hydrogen sulfide (H2S) in growth and metabolism of zucchini (Cucurbita pepo L.) was explored in a hydroponic culture system under both normal and nickel (Ni) stress conditions. Exposure of zucchini seedlings to 50 mg/l Ni(NO3)2 reduced root elongation and dry weight of roots and aerial parts. These reductions were attributed to Ni accumulation and depletion of essential bivalent cations in tissues. Excessive Ni resulted in the induction of oxidative stress, as evidenced by increased levels of electrolyte leakage (EL) and hydrogen peroxide (H2O2) content in roots and leaves. Moreover, Ni stress increased the endogenous H2S content in parallel with the accumulation of proline, soluble sugars, phenolics, and flavonoids in roots and leaves. Exogenous application of 100 µM sodium hydrosulfide (NaHS) as a donor of H2S singly or associated with Ni solution significantly improved zucchini growth but the impacts of NaHS were more pronounced in Ni-stressed plants than control seedlings. Notably, NaHS amplified the endogenous H2S content and maintained Ni and the homeostasis of cation in roots and aerial parts of Ni-stressed seedlings. Applying NaHS significantly lowered the accumulation of proline, whereas it elevated the content of soluble sugars in roots and leaves of Ni-stressed seedlings. Furthermore, applying NaHS decreased the EL and H2O2 content which were correlated to the enhancement of the phenolic and flavonoids content as well as 1,1-diphenyl-2-picrylhydrazyl radical and hydroxyl radical scavenging power in roots and leaves. By contrast, adding hypotaurine (HT), as a H2S scavenger, weakened the beneficial effect of NaHS on all above-mentioned traits that further confirmed the signaling role of H2S in regulating growth, membrane integrity, the content of phenolics and osmolytes, and mineral homeostasis under both control and Ni stress conditions.

Plants are frequently exposed to various environmental stressors, and their survival relies on intricate sensory mechanisms that detect and respond to these challenges. In recent years, several biomolecules have been identified as key regulators of plant responses to abiotic stresses. Lipids, one of crucial biomolecules serves as energy source, provides structural integrity and being a major component of plasma membranes forms the interface between the cell and the environment. Among the lipids, phosphatidic acid (PA), phosphoinositides, sphingolipids, lysophospholipids, oxylipins, and free fatty acids have been identified as substrates for stress-related signaling pathways. Despite the significance of these lipids, our understanding of their specific roles, interactions, and physiological impacts under conditions such as drought, salinity, and extreme temperatures remains limited. This review aims to synthesize recent advancements in our knowledge of lipid generation, distribution, and lipid-mediated signal transduction in response of plants to abiotic stresses. By exploring these processes, we seek to provide a comprehensive overview of lipid function in plant stress tolerance and identify potential avenues for future research.

Background There is speculation that beef bull semen quality is inferior to that of dairy bulls although few scientific studies are available in the literature. The aim of this study was to evaluate sperm quality in beef bull semen and to determine which parameters could be indicative of fertility after insemination. Sperm quality, assessed by computer assisted sperm motility analysis and flow cytometric evaluation of membrane integrity, levels of reactive oxygen species, mitochondrial membrane potential, acrosome status and DNA fragmentation index, was evaluated in beef and dairy bull semen. Results For beef bulls, normal morphology (r = 0.62, P < 0.05) and WOBBLE (r = 0.57, P < 0.05) were significantly correlated with 56-day non-return rate, whereas sperm quality was not significantly correlated with the fertility index score for dairy bulls. Membrane integrity (46 ± 8.0% versus 40 ± 11%, P < 0.05), normal morphology (87 ± 6% versus 76 ± 8%; P < 0.05), and high respiratory activity (52 ± 13 versus 12 ± 4%; P < 0.001) were higher for dairy bulls than for beef bulls. The DNA fragmentation index was lower for dairy bull spermatozoa than beef (3.8 ± 1.1% versus 6.1 ± 2.9%; P < 0.01), whereas some sperm kinematics were higher. Multivariate analysis indicated that type of bull (beef versus dairy) had an impact on sperm quality. Conclusions Different assays of sperm quality may be needed for appropriate analysis of beef and dairy bull semen. These finding could be important for cattle breeding stations when evaluating semen quality.

Two new compounds, macrolactin XY (1) and (5R, 9S, 10S)-5-(hydroxymethyl)-1,3,7-decatriene-9,10-diol (2), together with nine known compounds (3–11) were isolated from the marine Bacillus subtilis sp. 18 by the OSMAC strategy. These compounds were evaluated for antibacterial activity against six tested microorganisms. Compounds 1–5 and 7–10 showed varied antibacterial activity, with the minimum inhibitory concentration (MIC) ranging from 3 to 12 μg/mL. Macrolactin XY (1) was found to possess superior antibacterial activity, especially exhibiting significant effectiveness against Enterococcus faecalis. The antibacterial activity mechanism against E. faecalis was investigated. The mechanism may disrupt bacterial cell membrane integrity and permeability, and also inhibit the expression of genes associated with bacterial energy metabolism, as established by the experiments concerning cell membrane potential, SDS-PAGE electrophoresis, cell membrane integrity, and key gene expressions. This study offers valuable insights and serves as a theoretical foundation for the future development of macrolactins as antibacterial precursors.

To explore the mechanistic underpinnings of caffeine as a potent antibacterial against Staphylococcus aureus ATCC 25923 via in vitro functional assays, whole-genome sequencing, and in silico docking studies. In vitro studies established that caffeine’s minimum inhibitory concentration (MIC) against S. aureus ATCC 25923 is 0.01544 mmol/mL. Functional assays along with Scanning Electron Microscopy confirmed that caffeine at 0.030089 mmol/mL (2MIC) released nucleotide constituents (nucleotide leakage assay) and effluxed potassium ions (potassium efflux assay) thereby, further validating caffeine’s role as a membrane-active antimicrobial agent. Whole genome sequencing of control versus caffeine treated samples revealed a significant drop in read mapping percentage from 99.96 to 23.68% and GC content from 30.69 to 6.93%. This massive reduction in the treated sample was a consequence of single nucleotide polymorphisms (SNPs, 50,303), along with insertions and deletions (InDels, 62). Several of these caffeine-induced mutations were found to be harbouring the coding regions of genes involved in processes such as cell membrane organization, bacterial virulence, and DNA repair processes. Thus, implying a caffeine-mediated genomic rearrangement and instability . In silico docking studies revealed a strong binding affinity of caffeine to key cell wall proteins ltaA (-6.9 kcal/mol) and ltaS (-6.5 kcal/mol) respectively. The dynamic simulation studies revealed caffeine’s interaction with receptor ltaS remained stable, with low deviations and minimal fluctuations. Although caffeine has been widely investigated for its antibacterial properties, its specific mechanisms of action, notably its effects on the cell membrane and genomic integrity in S. aureus ATCC 25923, are little understood. This study thus offers a comprehensive functional genomic analysis of caffeine as an antibacterial against S. aureus .

Background Construction of microbial biocatalysts for the production of biorenewables at economically viable yields and titers is frequently hampered by product toxicity. Membrane damage is often deemed as the principal mechanism of this toxicity, particularly in regards to decreased membrane integrity. Previous studies have attempted to engineer the membrane with the goal of increasing membrane integrity. However, most of these works focused on engineering of phospholipids and efforts to identify membrane proteins that can be targeted to improve fatty acid production have been unsuccessful. Results Here we show that deletion of outer membrane protein ompF significantly increased membrane integrity, fatty acid tolerance and fatty acid production, possibly due to prevention of re-entry of short chain fatty acids. In contrast, deletion of fadL resulted in significantly decreased membrane integrity and fatty acid production. Consistently, increased expression of fadL remarkably increased membrane integrity and fatty acid tolerance while also increasing the final fatty acid titer. This 34% increase in the final fatty acid titer was possibly due to increased membrane lipid biosynthesis. Tuning of fadL expression showed that there is a positive relationship between fadL abundance and fatty acid production. Combinatorial deletion of ompF and increased expression of fadL were found to have an additive role in increasing membrane integrity, and was associated with a 53% increase the fatty acid titer, to 2.3 g/L. Conclusions These results emphasize the importance of membrane proteins for maintaining membrane integrity and production of biorenewables, such as fatty acids, which expands the targets for membrane engineering.