High Osmolarity Research Articles

Influence of Lifestyle Factors on Ocular Surface Parameters in Relation to Age

Purpose: To evaluate how Video Display Terminal (VDT) use, Contact Lens (CL) wear, and eyedrop use affect ocular surface parameters in participants with ocular discomfort and how these factors may vary across different age groups. Methods: The current cross-sectional study initially involved a total of 252 participants who completed a self-administered survey to collect information about ocular discomfort and lifestyle factors. This online survey was composed of an Ocular Surface Disease Index (OSDI) questionnaire and three extra questions regarding lifestyle factors (VDT use, CL wear, and eyedrop use). Only 185 symptomatic participants, those with OSDI values > 12, were scheduled to undergo a comprehensive ocular examination that included tear film osmolarity, Fluorescein Break-Up Time (FBUT), Maximum Blink Interval (MBI), and corneal staining. Results: Differences in ocular parameters and lifestyle factors across age groups (<40 years, 40–60 years, >60 years) were analyzed, along with their correlations and regression. Significant age group differences were found in OSDI, osmolarity, FBUT, and MBI (One-way ANOVA, all p ≤ 0.029). Correlations were observed between CL wear and osmolarity and MBI (Pearson’s correlation, both p ≤ 0.049). Multiple regression confirmed age associations with OSDI, osmolarity, FBUT, and MBI (Multiple linear regression, all p ≤ 0.040) and found links between VDT use and osmolarity and MBI (Multiple linear regression, both p ≤ 0.038) and between eyedrop use and OSDI (Multiple linear regression, p = 0.040). Conclusion: Aging is a primary factor affecting ocular homeostasis, with older adults showing lower FBUT and MBI values and higher osmolarity. Prolonged use of VDTs exacerbates this effect, further contributing to ocular discomfort and destabilized tear film. No associations between CL wear and any of the ocular parameters were found. Eyedrop use shows varied effects on ocular comfort across age groups, emphasizing the need for age-specific ocular care. Overall, these findings confirm that aging and extended VDT use play a significant role in ocular surface discomfort.

Novel Applications in Controlled Drug Delivery Systems by Integrating Osmotic Pumps and Magnetic Nanoparticles.

The alarming rise in chronic diseases worldwide highlights the urgent need to overcome the limitations of conventional drug delivery systems. In this context, osmotic pumps are able to release drugs by differential osmotic pressure, achieving a controlled rate independent of physiological factors and reducing the dosing frequency. As osmotic pumps are based on the phenomenon of osmosis, the choice of high osmolality draw solutions (DSs) is a critical factor in the successful delivery of the target drug. Therefore, one alternative that has received particular attention is the formulation of DSs with magnetic nanoparticles (MNPs) due to their easy recovery, negligible reverse solute flux (RSF), and their possible tailor-made functionalization to generate high osmotic gradients. In this work, the possible integration of DSs formulated with MNPs in controlled drug delivery systems is discussed for the first time. In particular, the main potential advantages that these novel medical devices could offer, including improved scalability, regeneration, reliability, and enhanced drug delivery performance, are provided and discussed. Thus, the results of this review may demonstrate the potential of MNPs as osmotic agents, which could be useful for advancing the design of osmotic pump-based drug delivery systems.

Evaluation of Plasma-Lyte Versus Lactated Ringer's in Surgical Intensive Care Unit Trauma Patients as Fluid Resuscitation.

In critically ill patients, fluid resuscitation with balanced crystalloids close to plasma osmolarity have a lower risk of electrolyte imbalances and demonstrated better clinical outcomes compared to normal saline (NS). While lactated ringer's (LR) has shown benefit over NS, plasma-lyte (PL) with a higher osmolarity and different electrolyte formulation is hypothesized to be superior. We performed a retrospective observational cohort study over 37 months at a tertiary hospital. Inclusion criteria were hospitalization in the surgical intensive care unit (SICU), trauma indication, ≥18 years old, and received either PL or LR. All PL administrations and every fifth patient with LR as resuscitation were included in order to match the sample size in each group. Primary outcomes were SICU length of stay (LOS), hospital LOS, and mortality. Secondary outcomes were biomarker changes from baseline. There were 113 patients in both PL and LR groups. The PL arm had higher APACHE II scores (16 vs 13, P = .033) and were more likely ventilated (39.3% vs 20.4%, P = .002) compared to LR. Median hospital LOS (12.0 vs 8.0, P < .001) and SICU LOS (6.0 vs 3.0, P < .001) are significantly longer in PL group compared to the LR group. However, there was no difference in in-hospital mortality (5.3% vs 3.5% P = .519) and SICU mortality (9.7% vs 5.3%, P > .208) between PL and LR. Overall, PL use was associated with prolonged hospital and SICU LOS. PL use did not demonstrate mortality benefit. However, patients were more critically ill in PL group based on higher APACHE II scores and higher rates of mechanical ventilation, which could be contributing to these unfavorable outcomes.

Altered sterol composition mediates multiple tolerance of Kluyveromyces marxianus for xylitol production

BackgroundCurrently, the synthesis of compounds based on microbial cell factories is rapidly advancing, yet it encounters several challenges. During the production process, engineered strains frequently encounter disturbances in the cultivation environment or the impact of their metabolites, such as high temperature, acid-base imbalances, hypertonicity, organic solvents, toxic byproducts, and mechanical damage. These stress factors can constrain the efficiency of microbial fermentation, resulting in slow cell growth, decreased production, significantly increased energy consumption, and other issues that severely limit the application of microbial cell factories.ResultsThis study demonstrated that sterol engineering in Kluyveromyces marxianus, achieved by overexpressing or deleting the coding genes for the last five steps of ergosterol synthase (Erg2-Erg6), altered the composition and ratio of sterols in its cell membrane, and affected its multiple tolerance. The results suggest that the knockout of the Erg5 can enhance the thermotolerance of K. marxianus, while the overexpression of the Erg4 can improve its acid tolerance. Additionally, engineering strain overexpressed Erg6 improved its tolerance to elevated temperature, hypertonic, and acid. YZB453, obtained by overexpressing Erg6 in an engineering strain with high efficiency in synthesizing xylitol, produced 101.22 g/L xylitol at 45oC and 75.11 g/L xylitol at 46oC. Using corncob hydrolysate for simultaneous saccharification and fermentation (SSF) at 46oC that xylose released from corncob hydrolysate by saccharification with hemicellulase, YZB453 can produce 45.98 g/L of xylitol, saving 53.72% of the cost of hemicellulase compared to 42oC.ConclusionsThis study elucidates the mechanism by which K. marxianus acquires resistance to various antifungal drugs, high temperatures, high osmolarity, acidity, and other stressors, through alterations in the composition and ratio of membrane sterols. By employing sterol engineering, the fermentation temperature of this unconventional thermotolerant K. marxianus was further elevated, ultimately providing an efficient platform for synthesizing high-value-added xylitol from biomass via the SSF process at temperatures exceeding 45 °C.

Suggested guide to using lactate gap as a surrogate marker in the diagnosis of ethylene glycol overdose.

Ethylene glycol (EG) poisoning, if not diagnosed rapidly, can lead to poor patient outcomes. Gas Chromatography (GC) is primarily used for EG quantitation which is rarely available, and the turn-around time may be prolonged. Most lactate results from point-of care (POCT) methods are falsely elevated in EG poisoning compared with automated chemistry analyser results. In combination the lactate gap (POCT-Automated chemistry) can be used as surrogate marker in just about all laboratories to indicate likely EG toxicity and guide treatment. A male presented by ambulance to hospital with severe agitation requiring mechanical ventilation to facilitate ongoing management. Venous blood gas analysis confirmed a high anion gap metabolic acidosis (HAGMA) with an elevated lactate. The lactate and osmolarity measured in the laboratory showed a normal lactate and high osmolarity, giving a large osmolar gap. The patient was immediately commenced on renal replacement therapy for presumed EG poisoning to minimize kidney injury, and the treatment continued for 19 hours. A very high EG concentration was confirmed by GC the next day. An elevated lactate gap along with a HAGMA and osmolar gap can provide rapid surrogate laboratory data indicating EG poisoning enabling timely treatment and better patient outcomes.

25SrRNA Methyltransferase CgBMT5 From Candida glycerinogenes Improves Tolerance and Fermentation Performance of Saccharomyces cerevisiae and Yarrowia lipolytica From Undetoxified Cellulose Hydrolysate.

The hydrolysis of cellulose generates inhibitors like acetate, suppressing fermentation performance. Here, 25SrRNA methyltransferase CgBMT5 from stress-tolerant yeast Candida glycerinogenes was used as an anti-stress gene element in Saccharomyces cerevisiae and Yarrowia lipolytica. Expression of CgBMT5 in S. cerevisiae increased cell tolerance to acetate, high osmolarity, and heat stress and rescued the delay in cell growth under acetate stress. Ethanol productivity was improved from 0.52 g·(L/h) to 0.69 g·(L/h). CgBMT5 improved GFP expression. The transcription factor ARG81 binds to the promoter of CgBMT5. CgBMT5 upregulated HOG1, GPD1, HAA1, and PMA1 and reduced ROS level, thereby improving cell resistance to acetate. CgBMT5 also improved resistance of Y. lipolytica Po1g to multiple-stress. The lipid titer was improved by 37% in the typical medium. Y. lipolytica-CgBMT5 produced 94mg/L lipid in the undetoxified cellulose hydrolysate.

Association between serum osmolality and deteriorating renal function in patients with acute myocardial infarction: analysis of the MIMIC- IV database

BackgroundTo investigate the association between serum osmolality and deteriorating renal function in patients with acute myocardial infarction (AMI).MethodsThree thousand eight hundred eighty-five AMI patients from the Medical Information Mart for Intensive Care IV were enrolled for this study. The primary outcome was deteriorating renal function. Secondary outcomes included the new-onset of acute kidney injury (AKI) and progress of AKI. < 293.2725 mmol/L was defined as low serum osmolality, and ≥ 293.2725 mmol/L as high serum osmolality based on upper quartile. Univariate and multivariate logistic regression models were used to explore the associations between serum osmolality and the development of deteriorating renal function, the new-onset of AKI and progress of AKI among AMI patients. Subgroup analysis was also conducted.ResultsOne thousand three hundred ninety-three AMI patients developed deteriorating renal function. After adjusting all confounding factors, high serum osmolality was associated with increased risk of deteriorating renal function [odds ratio (OR) = 1.47, 95% confidence interval (CI): 1.22–1.78], new-onset of AKI (OR = 1.31, 95% CI: 1.01–1.69), and progress of AKI risk (OR = 1.26, 95% CI: 1.01–1.59) among AMI patients. In addition, when the stratified analysis was performed for age, AMI type, cardiogenic shock, and estimated glomerular filtration rate (eGFR), high serum osmolality was risk factor for the risk of deteriorating renal function among patients aged 65 years or older, without cardiogenic shock, and with an eGFR ≥ 60 mL/min/1.73m2.ConclusionHigher serum osmolality increased the risk of deteriorating renal function among AMI patients.

A novel approach for perfusion process design based on a "Grey-Box" kinetic model.

Perfusion cell-culture mode has caught industrial interest in the field of biomanufacturing in recent years. Thanks to new technology, perfusion-culture processes can support higher cell densities, higher productivities and longer process times. However, due to the inherent operational complexity and high running costs, the development and design of perfusion-culture processes remain challenging. Here, we present a model-based approach to design optimized perfusion cultures of Chinese Hamster Ovary cells. Initially, four batches of bench-top reactor continuous-perfusion-culture data were used to fit the model parameters. Then, we proposed the model-based process design approach, aiming to quickly find out the "theoretically optimal" operational parameters combinations (perfusion rate and the proportion of feed medium in perfusion medium) which could achieve the target steady-state VCD while minimizing both medium cost and perfusion rate during steady state. Meanwhile, we proposed a model-based dynamic operational parameters-adjustment strategy to address the issue of cell-growth inhibition due to the high osmolality of concentrated perfusion medium. In addition, we employed a dynamic feedback control method to aid this strategy in preventing potential nutrient depletion scenarios. Finally, we test the feasibility of the model-based process design approach in both shake flask semi-perfusion culture (targeted at 5 × 107 cells/ml) and bench-top reactor continuous perfusion culture (targeted at 1.1 × 108 cells/ml). This approach significantly reduces the number of experiments needed for process design and development, thereby accelerating the advancement of perfusion-mode cell-culture processes.

PCL-gelatin honey scaffolds promote Staphylococcus aureus agrA expression in biofilms with Pseudomonas aeruginosa.

Bacterial infection and biofilm formation contribute to impaired healing in chronic diabetic wounds. Staphylococcus aureus and Pseudomonas aeruginosa are found in human diabetic wound biofilms. They may develop antibiotic resistance, increasing the urgency for alternative or complementary therapies. Diabetic wound healing may be improved with the use of biomedically engineered scaffolds, which can also serve as delivery systems for antibacterial compounds. Manuka honey is a potent antibacterial and wound care agent due to its high osmolarity, low pH, and constituents (such as methylglyoxal). Honey exhibits bacteriostatic and bactericidal effects, modulates the expression of biofilm forming genes, and restores antibiotic susceptibility in previously drug resistant pathogens. In this study, we created a dermal regeneration template (DRT) composed of polycaprolactone-gelatin (PCL-gelatin) and Manuka honey to retain honey in the wound and also provide a scaffold for tissue regeneration. Soluble Manuka honey inhibited the planktonic and biofilm growth of both S. aureus (UWH3) and P. aeruginosa (PA14) co-cultures. Manuka honey embedded PCL-gelatin scaffolds did not exhibit bacteriostatic or bactericidal effects on cocultures of UHW3 and PA14; however, they promoted the expression of AgrA, a gene associated with dispersal of S. aureus biofilms.

Adverse effects of human milk fortifier on preterm neonates in a neonatal intensive care unit of a tertiary care hospital, Karachi.

Objective: To determine adverse effects of Human Milk Fortifier on Preterm neonates in a Neonatal Intensive Care Unit. Study Design: Descriptive study. Setting: Indus Hospital NICU in Karachi. Period: Mar 2022 to September 2023. Methods: Aimed to investigate the adverse effects of HMF on 139 preterm neonates. The study excluded infants with congenital anomalies. Adverse effects, including Necrotizing Enterocolitis (NEC), metabolic acidosis, feeding intolerance, and other complications, were monitored. Results: The findings revealed that feeding intolerance was the most common adverse effect of HMF. Mild metabolic acidosis and NEC were also observed. These results are consistent with previous studies and may be attributed to the high osmolality of feeds following fortification with HMF. Despite the well-established role of HMF in promoting weight gain in preterm infants, the study underscores the importance of closely monitoring its use. Conclusion: Careful consideration of the potential risks and benefits of HMF is essential before prescribing it to preterm neonates. Future research with larger sample sizes and controlled designs is needed to validate these findings and explore strategies to mitigate the adverse effects of HMF in NICU settings.

Integrated sperm movement, proteomics, and phosphoproteomics elucidate the roles of osmolality, ions, and key proteins in sperm activation of Nile tilapia (Oreochromis niloticus)

Nile tilapia (Oreochromis niloticus) is an important aquaculture fish around the world and has a wide range of tolerance to salinity, providing great economic value in aquaculture industry and showing an excellent ecological adaptation. However, the best sperm activation condition and sperm activation mechanism of this euryhaline fish remains unclear. In this study, we applied the sperm movement analysis, proteomics, and phosphoproteomics to explore the effects of osmolality and ions and to reveal sperm activation mechanism of Nile tilapia. Our results showed that low osmolality contributed to sperm activation compared with high osmolality. Adding Na+ and Ca2+ enhanced sperm motility after sperm activation. Under 100 mOsm·kg−1, adding 44 mM Na+ and 4 mM Ca2+ was a successful protocol for sperm activation. Proteomics and phosphoproteomics analyses identified 677 differentially expressed proteins and 245 differentially expressed phosphorylated proteins, respectively, among which 21 proteins and 11 phosphorylated proteins as key molecules were involved in Ca2+ mediated signal transduction, glucose metabolism, lipid metabolism, and apoptotic cell death. Key protein ORAI1 promoted extracellular Ca2+ influx to activate Ca2+ mediated signal transduction. Converting glycogenolysis and glycolysis to pyruvate metabolism and fatty acid β-oxidation was a critical energy metabolic adaptation mechanism. The Hsp90 was a critical sperm activation biomarker in loosing of sperm motility and apoptosis. A putative proteomic and phosphoproteomic response network was constructed to reveal the sperm activation mechanism of Nile tilapia. Our study provides a new insight into sperm activation mechanism of this euryhaline fish and facilitates future application of best activation protocol to the fertilization and breeding of Nile tilapia.

A Buffered Local Anesthetic Without Epinephrine: Development, Characterization, and In Vivo Efficacy and Toxicity Analysis.

Lidocaine hydrochloride (HCl) 2% with 1:100,000 epinephrine (LW/E) is widely used to prevent pain during dental procedures and has been associated with injection sting, jittering effects, slow onset, and a bitter aftertaste. Since LW/E's introduction in 1948, no significant modifications have been proposed. This study aims to design and characterize an improved dental lidocaine HCl injectable formulation without epinephrine (LW/O/E) via buffers, sweeteners, and amino acids. LW/O/E injections were prepared with pH and osmolality values of 6.5-7.0 and 590-610 mOsm/kg. Using the electronic tongue (ETongue), the LW/O/E injectable formulations were characterized for viscosity, injectability, and taste analysis. The results were compared with the LW/E control. In vivo efficacy and anesthetic duration of the samples were measured through radiant heat tail-flick latency (RHTFL) and hot plate (HP) tests and local toxicity was assessed after a single intra-oral injection in Sprague Dawley rats (SDR). The viscosity and injectability values of the LW/O/E samples were found to be comparable to the LW/E injection. ETongue taste analysis showed an improvement in bitterness reduction of the LW/O/E samples compared to the LW/E formulation. Toxicity studies of samples in SDR showed minor and transient signs of erythema/eschar and edema. Anesthetic duration via RHTFL and HP paw withdrawal latency time in SDR were found to be comparable for the LW/O/E Sample 3A and the LW/E injection (p < 0.05). In conclusion, the buffered, higher osmolality and reduced bitterness developed LW/O/E formulation (Sample 3A) could be considered a promising alternative to the LW/E formulation for dental use.

Shared and redundant proteins coordinate signal cross-talk between MAPK pathways in yeast.

All cells must detect, interpret, and adapt to multiple and concurrent stimuli. While signaling pathways are highly specialized, different pathways often share components or have components with overlapping functions. In the yeast Saccharomyces cerevisiae, the high osmolarity glycerol (HOG) pathway has two seemingly redundant branches, mediated by Sln1 and Sho1. Both branches are activated by osmotic pressure, leading to phosphorylation of the MAPKs Hog1 and Kss1. The mating pathway is activated by pheromone, leading to phosphorylation of the MAPKs Fus3 and Kss1. Given that Kss1 is shared by the two pathways, we investigated its role in signal coordination. We activated both pathways with a combination of salt and pheromone, in cells lacking the shared MAPK and in cells lacking either of the redundant branches of the HOG pathway. By systematically evaluating MAPK activation, translocation, and transcription programs, we determined that Sho1 mediates cross talk between the HOG and mating pathways and does so through Kss1. Further, we show that Kss1 initiates a transcriptional program that is distinct from that induced by Hog1 and Fus3. Our findings reveal how redundant and shared components coordinate concurrent signals and thereby adapt to sudden environmental changes.

Osmotic stress response of the coral and oyster pathogen Vibrio coralliilyticus: acquisition of catabolism gene clusters for the compatible solute and signaling molecule myo-inositol.

Marine bacteria experience fluctuations in osmolarity that they must adapt to, and most bacteria respond to high osmolarity by accumulating compatible solutes also known as osmolytes. The osmotic stress response and compatible solutes used by the coral and oyster pathogen Vibrio coralliilyticus were unknown. In this study, we showed that to alleviate osmotic stress V. coralliilyticus biosynthesized glycine betaine (GB) and transported into the cell choline, GB, ectoine, dimethylglycine, and dimethylsulfoniopropionate, but not myo-inositol. Myo-inositol is a stress protectant and a signaling molecule that is biosynthesized and used by algae. Bioinformatics identified myo-inositol (iol) catabolism clusters in V. coralliilyticus and other Vibrio, Photobacterium, Grimontia, and Enterovibrio species. Growth pattern analysis demonstrated that V. coralliilyticus utilized myo-inositol as a sole carbon source, with a short lag time of 3 h. An iolG deletion mutant, which encodes an inositol dehydrogenase, was unable to grow on myo-inositol. Within the iol clusters were an MFS-type (iolT1) and an ABC-type (iolXYZ) transporter and analyses showed that both transported myo-inositol. IolG and IolA phylogeny among Vibrionaceae species showed different evolutionary histories indicating multiple acquisition events. Outside of Vibrionaceae, IolG was most closely related to IolG from a small group of Aeromonas fish and human pathogens and Providencia species. However, IolG from hypervirulent A. hydrophila strains clustered with IolG from Enterobacter, and divergently from Pectobacterium, Brenneria, and Dickeya plant pathogens. The iol cluster was also present within Aliiroseovarius, Burkholderia, Endozoicomonas, Halomonas, Labrenzia, Marinomonas, Marinobacterium, Cobetia, Pantoea, and Pseudomonas, of which many species were associated with marine flora and fauna.IMPORTANCEHost associated bacteria such as Vibrio coralliilyticus encounter competition for nutrients and have evolved metabolic strategies to better compete for food. Emerging studies show that myo-inositol is exchanged in the coral-algae symbiosis, is likely involved in signaling, but is also an osmolyte in algae. The bacterial consumption of myo-inositol could contribute to a breakdown of the coral-algae symbiosis during thermal stress or disrupt the coral microbiome. Phylogenetic analyses showed that the evolutionary history of myo-inositol metabolism is complex, acquired multiple times in Vibrio, but acquired once in many bacterial plant pathogens. Further analysis also showed that a conserved iol cluster is prevalent among many marine species (commensals, mutualists, and pathogens) associated with marine flora and fauna, algae, sponges, corals, molluscs, crustaceans, and fish.

Activation of the Alpha 7 Nicotinic Acetylcholine Receptor by GTS-21 Mitigates Contrast Nephropathy in a Rat Model.

Contrast nephropathy (CN) is characterized by oxidative stress, vasoconstriction, tubular toxicity, and hypoxia of the renal medulla. We aimed to test the therapeutic effects of an α7 nicotinic acetylcholine receptor (nAChR) agonist, GTS-21, in an experimental CN model. Male Sprague-Dawley rats (n = 40) were divided into 4 groups: saline-treated control, GTS-21-treated control, contrast, and GTS-21-treated contrast groups. Starting on the 1st day, GTS-21 (4 mg/kg, intraperitoneally) or saline was administered twice a day for 3 days. CN was induced on the second day by intravenous injection of indomethacin (10 mg/kg), <sc>l</sc>-NAME (10 mg/kg), and a contrast agent with high osmolarity (6 mL/kg; Urografin 76%). At the 72nd hour, blood and kidney samples were obtained for the determination of biochemical, histological, and gene expression parameters. Compared to those in control rats, the elevated serum BUN level in the contrast group decreased with GTS-21 treatment, while H&amp;E staining and TUNEL assays showed that contrast-induced renal injury was improved by GTS-21. Moreover, GTS-21 treatment in the CN also increased the antioxidant glutathione level. In the contrast group, a significant increase in IL-6 expression and a decrease in TGF-β expression were observed; however, GTS-21 treatment decreased IL-6 expression and increased TGF-β expression. GTS-21 significantly alleviated renal injury parameters through antioxidant, anti-inflammatory, and antiapoptotic mechanisms in the CN model.

The target of rapamycin signaling pathway regulates vegetative development, aflatoxin biosynthesis, and pathogenicity in Aspergillus flavus.

The target of rapamycin (TOR) signaling pathway is highly conserved and plays a crucial role in diverse biological processes in eukaryotes. Despite its significance, the underlying mechanism of the TOR pathway in Aspergillus flavus remains elusive. In this study, we comprehensively analyzed the TOR signaling pathway in A. flavus by identifying and characterizing nine genes that encode distinct components of this pathway. The FK506-binding protein Fkbp3 and its lysine succinylation are important for aflatoxin production and rapamycin resistance. The TorA kinase plays a pivotal role in the regulation of growth, spore production, aflatoxin biosynthesis, and responses to rapamycin and cell membrane stress. As a significant downstream effector molecule of the TorA kinase, the Sch9 kinase regulates aflatoxin B1 (AFB1) synthesis, osmotic and calcium stress response in A. flavus, and this regulation is mediated through its S_TKc, S_TK_X domains, and the ATP-binding site at K340. We also showed that the Sch9 kinase may have a regulatory impact on the high osmolarity glycerol (HOG) signaling pathway. TapA and TipA, the other downstream components of the TorA kinase, play a significant role in regulating cell wall stress response in A. flavus. Moreover, the members of the TapA-phosphatase complexes, SitA and Ppg1, are important for various biological processes in A. flavus, including vegetative growth, sclerotia formation, AFB1 biosynthesis, and pathogenicity. We also demonstrated that SitA and Ppg1 are involved in regulating lipid droplets (LDs) biogenesis and cell wall integrity (CWI) signaling pathways. In addition, another phosphatase complex, Nem1/Spo7, plays critical roles in hyphal development, conidiation, aflatoxin production, and LDs biogenesis. Collectively, our study has provided important insight into the regulatory network of the TOR signaling pathway and has elucidated the underlying molecular mechanisms of aflatoxin biosynthesis in A. flavus.

Effects of Total Parenteral Nutrition on Serum Osmolality and Patent Ductus Arteriosus.

The persistence of high serum osmolality in the early postnatal period is a risk for developing patent ductus arteriosus (PDA). Early aggressive nutrition (EAN), involving total parenteral nutrition (TPN), by which enough concentrations of glucose and amino acids are administered intravenously, is recommended postnatally to improve the neurological prognosis in preterm infants. However, the effects of EAN involving TPN on serum osmolality and the development of a PDA have not been adequately studied. Thus, in this study, we aimed to investigate the impact of TPN on serum osmolality and determine whether increased serum osmolality could be associated with a higher incidence of PDA in preterm infants. In this single-center retrospective observational study, preterm infants born at <28 weeks of gestation who had been admitted to our neonatal intensive care unit (NICU) before (pre-TPN period) and after the introduction of TPN (post-TPN) were included. We reviewed the medical records of these patients, compared the changes in serum osmolality from birth to five days after birth, the clinical background, and the incidence of PDA between these two periods, and analyzed the risk factors. Additionally, the factors affecting the serum osmolality in very preterm infants were examined. The patients who met the intervention criteria of our NICU and received a cyclooxygenase (COX) inhibitor, Indacin® (Nobelpharma, Tokyo, Japan), within seven days after birth were classified as PDA+; those who could not be identified to have PDA flow by echo and did not receive a COX inhibitor were classified as PDA-. The postnatal day and serum sodium (Na+) were statistically significantly correlated with a higher serum osmolality. Serum osmolality remained statistically significantly higher in the PDA+ cohort compared with the PDA- cohort after the first day of life. However, no statistically significant differences were observed in serum osmolality after 24 hours of age, weeks of gestational age, birth weight, or incidence of PDA between the pre- and post-TPN periods. The results of the multiple logistic regression analyses revealed that the increased serum osmolality correlated with PDA development. In this study, the serum Na+ statistically significantly correlated with a higher serum osmolality. Moreover, the increased serum osmolality correlated with PDA development. Thus, the prevention of hypernatremia might reduce the incidence of PDA. Nonetheless, the findings in this study revealed that no statistically significant differences in serum osmolality were observed between the pre-and post-TPN periods, indicating that TPN had little effect on serum osmolality.

Optimizing extenders for short-term storage of Sterlet (Acipenser ruthenus) sperm

Considering endangered fish, storage of sterlet (Acipenser ruthenus) gamete is crucial, and investigating the most suitable extender for short-term storage of sperm is necessary. Therefore, the present study aimed to optimize suitable extenders for short-term storage of sterlet spermatozoa and determine the effects of storage periods and different extenders on spermatozoa motility parameters. The sperm of five mature males with good spermatozoa motility (∼80 %) were diluted with 20 different extenders having various Na+ and K+ concentrations and osmolality. Spermatozoa motility performances were assessed using a CASA system within 144 h storage at 0–2 °C. Undiluted sperm was used as a control. Seminal plasma Na+, K+, Ca2+ and Cl- concentrations were 17.56±10.12, 2.48±1.14, 0.11±0.06, and 6.20±3.42 mmol/L with osmolality of 35.60±20.70 mOsm/kg. A two-way ANOVA showed significant effects of storage time, extender, and their interaction on spermatozoa motility, curvilinear velocity (VCL), and straight-line velocity (VSL) (p<0.001). The model was decomposed into one-way ANOVA to study the effects of storage time and extenders. Excluding 1 h post-storage, spermatozoa motility, VCL, and VSL were lower in the non-diluted sperm than those diluted with E18-E20 at 24 h post-storage (p<0.05). The osmolality of these extenders was respectively 46, 55, and 62 mOsmol/kg and contained 1 mM KCl. Increasing the extender KCl concentrations to >3 mM resulted in lower spermatozoa motility performance. When the effects of storage time were studied, spermatozoa motility, VCL, and VSL in non-diluted sperm and those diluted with E18-E20 were decreased at 24–48 h and 72–96 h post-storage, respectively. This study shows that extenders with higher osmolality (39–62 mOsm/kg) and lower K+ (1 mmol/L) are the most suitable for storing sterlet sperm for a short period.

Genetic evidence for a regulated cysteine protease catalytic triad in LegA7, a Legionella pneumophila protein that impinges on a stress response pathway.

Legionella pneumophila grows within membrane-bound vacuoles in phylogenetically diverse hosts. Intracellular growth requires the function of the Icm/Dot type-IVb secretion system, which translocates more than 300 proteins into host cells. A screen was performed to identify L. pneumophila proteins that stimulate MAPK activation, using Icm/Dot translocated proteins ectopically expressed in mammalian cells. In parallel, a second screen was performed to identify L. pneumophila proteins expressed in yeast that cause growth inhibition in MAPK pathway-stimulatory high osmolarity medium. LegA7 was shared in both screens, a protein predicted to be a member of the bacterial cysteine protease family that has five carboxyl-terminal ankyrin repeats. Three conserved residues in the predicted catalytic triad of LegA7 were mutated. These mutations abolished the ability of LegA7 to inhibit yeast growth. To identify other residues important for LegA7 function, a generalizable selection strategy in yeast was devised to isolate mutants that have lost function and no longer cause growth inhibition on high osmolarity medium. Mutations were isolated in the two carboxyl-terminal ankyrin repeats, as well as an inter-domain region located between the cysteine protease domain and the ankyrin repeats. These mutations were predicted by AlphaFold modeling to localize to the face opposite from the catalytic site, arguing that they interfere with the positive regulation of the catalytic activity. Based on our data, we present a model in which LegA7 harbors a cysteine protease domain with an inter-domain and two carboxyl-terminal ankyrin repeat regions that modulate the function of the catalytic domain.

(045) A PHYSICIAN'S GUIDE TO LUBRICANT FOR SEX

Abstract Introduction Lubricant use during sexual activity has numerous benefits, minimal harms, and can play a role in managing common concerns in primary care. However, navigating evidence-based conversations about lubricant use can be challenging since there is a lack of easily accessible and reliable information. As a result, physicians are often hesitant to discuss the topic and can only offer anecdotal advice. Objective To review literature on lubricants used during sexual activity to (1) inform the development of an inclusive and practical evidence-based tool for physicians to help incorporate patient-specific recommendations for lubricants into clinical practice, and (2) create accessible materials for patients. Methods We conducted a scoping review of peer-reviewed literature using the Arksey and O’Malley framework. Using relevant keywords, we searched two electronic databases, one search engine, and reference lists for articles published in 2003 and onward. Articles generated were manually reviewed for relevance with further inclusion criteria: (1) identifies patient populations most likely to benefit from using lubricant during sexual activity, (2) addresses benefits and drawbacks of different lubricant classes, or (3) describes ingredients in or properties of lubricants that may cause harm. All sexually active individuals were deemed eligible for inclusion in the study, with no restrictions placed on location, age, gender, or sexual orientation. Following the completion of our scoping review, we used an evidence-based approach to develop a clinical practice tool and patient handout. During their development and to validate our findings, family physicians, nurses, psychologists specializing in sexual concerns, and sexual health educators provided iterative review. Results 27 articles were deemed eligible for inclusion in our scoping review. Results showed lubricant use to be especially beneficial for patients who (1) experience dryness, pain, or sexual dysfunction during any type of sex, (2) are at a higher risk of STI transmission (by reducing condom breakage), or (3) want to reduce the risk of having an unplanned pregnancy (by reducing condom breakage). There are three main types of lubricant available: oil, water, and silicone-based. Oil-based lubricant is not recommended since it is incompatible with latex condoms and is more likely to irritate genital epithelium and negatively impact genital microbiota. When comparing silicone and water-based lubricant, silicone-based lubricant lasts longer but is more difficult to wash off. Silicone-based lubricant is not compatible with silicone-based sex toys, whereas water-based lubricant is compatible with all types of sex toys. Water-based lubricant is also more likely than silicone-based lubricant to contain potentially irritating ingredients and properties, such as glycerol, propylene glycol, parabens, or a high osmolality. For patients who are struggling with infertility, most lubricants should be avoided as they can negatively affect sperm motility and viability. Conclusions Numerous patients can benefit from lubricant use during sexual activity. In particular, silicone and water-based lubricant without harmful additives or properties are recommended. Our guide on lubricants will assist physicians in identifying patients who may benefit from using lubricant and incorporating patient-specific recommendations into clinical practice. This, in addition to our patient handout, will help to improve discussions between patients and healthcare providers regarding sexual well-being and lubricant use. Disclosure No.