Potential of fructans as natural cryoprotectant agents in plant cryopreservation: concept validation on Arabidopsis thaliana L.

BACKGROUND: Today, synthetic chemicals are used in vitrification solutions for cryopreservation studies to mimic natural cryoprotectants that supply tolerance to organisms in nature against freezing stress. In the case of plants, PVS2, containing glycerol, dimethyl sulfoxide (Me2SO), ethylene glycol and sucrose, is considered as the golden standard for successful cryopreservation. However, Me2SO can generally cause toxicity to certain plant cells, adversely affecting viability after freezing and/or thawing. Hence, the replacement (or substantial reduction) of Me2SO by cheap, non-toxic and natural cryoprotectants became a matter of high priority to vitrification solutions or reducing their content gained escalating importance for the cryopreservation of plants. Fructans, sucrose derivatives mainly consisting of fructose residues, are candidate cryoprotectants. OBJECTIVE: Inspired by their protective role in nature, we here explored, for the first time, the potential of an array of 8 structurally different fructans as cryoprotectants in plant cryopreservation. MATERIALS AND METHODS: Arabidopsis thaliana L. seedlings were used as a model system with a one-step vitrification method. PVS2 solutions with different Me2SO and fructan contents were evaluated. RESULTS: It was found that branched low DP graminan, extracted from milky stage wheat kernels, led to the highest recovery (85%) among tested fructans with 12.5% Me2SO after cryopreservation, which was remarkably close to the viability (90%) observed with the original PVS2 containing 15% Me2SO. Moreover, its protective efficacy could be further optimized by addition of vitamin C acting as an antioxidant. CONCLUSION: Such novel formulations offer great perspectives for cryopreservation of various crop species. Doi.org/10.54680/fr24410110512.

Effective cryopreservation of human brain tissue and neural organoids.

Human brain tissue models and organoids are vital for studying and modeling human neurological disease. However, the high cost of long-term cultured organoids inhibits their wide-ranging application. It is therefore urgent to develop methods for the cryopreservation of brain tissue and organoids. Here, we establish a method using methylcellulose, ethylene glycol, DMSO, and Y27632 (termed MEDY) for the cryopreservation of cortical organoids without disrupting the neural cytoarchitecture or functional activity. MEDY can be applied to multiple brain-region-specific organoids, including the dorsal/ventral forebrain, spinal cord, optic vesicle brain, and epilepsy patient-derived brain organoids. Additionally, MEDY enables the cryopreservation of human brain tissue samples, and pathological features are retained after thawing. Transcriptomic analysis shows that MEDY can protect synaptic function and inhibit the endoplasmic reticulum-mediated apoptosis pathway. MEDY will enable the large-scale and reliable storage of diverse neural organoids and living brain tissue and will facilitate wide-ranging research, medical applications, and drug screening.

Establishment of an artificial urine model in vitro and rat or pig model in vivo to evaluate urinary crystal adherence.

The current study aimed to establish an experimental model in vitro and in vivo of urinary crystal deposition on the surface of ureteral stents, to evaluate the ability to prevent crystal adhesion. Non-treated ureteral stents were placed in artificial urine under various conditions in vitro. In vivo, ethylene glycol and hydroxyproline were administered orally to rats and pigs, and urinary crystals and urinary Ca were investigated by Inductively Coupled Plasma-Optical Emission Spectrometer. in vitro, during the 3- and 4-week immersion periods, more crystals adhered to the ureteral stent in artificial urine model 1 than the other artificial urine models (p < 0.01). Comparing the presence or absence of urea in the composition of the artificial urine, the artificial urine without urea showed less variability in pH change and more crystal adhesion (p < 0.05). Starting the experiment at pH 6.3 resulted in the highest amount of crystal adhesion to the ureteral stent (p < 0.05). In vivo, urinary crystals and urinary Ca increased in rat and pig experimental models. This experimental model in vitro and in vivo can be used to evaluate the ability to prevent crystal adhesion and deposition in the development of new ureteral stents to reduce ureteral stent-related side effects in patients.

Herbo-Mineral Medicine, Lithom Exhibits Anti-Nephrolithiasis Activity in Rat Model of Hyperoxaluria by Attenuating Calcium Oxalate Crystal Formation and Oxidative Stress.

BACKGROUND: Calcium oxalate monohydrate (COM) forms the most common type of kidney stones observed in clinics, elevated levels of urinary oxalate being the principal risk factor for such an etiology. The objective of the present study was to evaluate the anti-nephrolithiatic effect of herbo-mineral formulation, Lithom. METHODS: The in vitro biochemical synthesis of COM crystals in the presence of Lithom was performed and observations were made by microscopy and Scanning Electron Microscope (SEM) based analysis for the detection of crystal size and morphology. The phytochemical composition of Lithom was evaluated by Ultra-High-Performance Liquid Chromatography (UHPLC). The in vivo model of Ethylene glycol-induced hyperoxaluria in Sprague-Dawley rats was used for the evaluation of Lithom. The animals were randomly allocated to 5 different groups namely Normal control, Disease control (ethylene glycol (EG), 0.75%, 28 days), Allopurinol (50 mg/kg, q.d.), Lithom (43 mg/kg, b.i.d.), and Lithom (129 mg/kg, b.i.d.). Analysis of crystalluria, oxalate, and citrate levels, oxidative stress parameters (malondialdehyde (MDA), catalase, myeloperoxidase (MPO)), and histopathology by hematoxylin and eosin (H&E) and Von Kossa staining was performed for evaluation of Lithom. RESULTS: The presence of Lithom during COM crystals synthesis significantly reduced the average crystal area, feret's diameter, and area-perimeter ratio, in a dose-dependent manner. SEM analysis revealed that COM crystals synthesized in the presence of 100 and 300 µg/mL of Lithom exhibited a veritable morphological transition from irregular polygons with sharp edges to smoothened smaller cuboid polygons. UHPLC analysis of Lithom revealed the presence of Trigonelline, Bergenin, Xanthosine, Adenosine, Bohoervinone B, Vanillic acid, and Ellagic acid as key phytoconstituents. In EG-induced SD rats, the Lithom-treated group showed a decrease in elevated urinary oxalate levels, oxidative stress, and renal inflammation. Von Kossa staining of kidney tissue also exhibited a marked reduction in crystal depositions in Lithom-treated groups. CONCLUSION: Taken together, Lithom could be a potential clinical-therapeutic alternative for management of nephrolithiasis.

Fomepizole use reported to United States Poison Centers from 2010 to 2021.

BACKGROUND: The diagnosis of toxic alcohol poisoning is often based on clinical presentation and nonspecific surrogate laboratory studies due to limited testing availability. Fomepizole is the recommended antidote and often administered empirically. The objective of this study is to identify substances that mimic toxic alcohols and compare key clinical factors between toxic alcohol and non-toxic alcohol exposures when fomepizole was administered. METHODS: This study was a retrospective evaluation using the National Poison Data System from January 1, 2010 through December 31, 2021. Exposures were included if fomepizole was administered. Toxic alcohol exposures had ethylene glycol or methanol as a coded substance. For exposures not coded as a toxic alcohol, the first substance was described. Paracetamol (acetaminophen) exposures from 2020 and 2021 were excluded. RESULTS: Fomepizole was reportedly used 25,110 times over 12 years. Use increased from 1,955 in 2010 to 2,710 in 2021. Most administrations were for reported toxic alcohol poisoning (60 percent) but use in reported non-toxic alcohol poisoning was greater starting in 2020. Toxic alcohol exposures were older (43.3 versus 39.8 years; P < 0.001) and more likely male (65.7 percent versus 58.2 percent). Level of care was mostly a critical care unit (67.7 percent), which was less common in toxic alcohol (63.3 percent) than non-toxic alcohol exposures (74.2 percent). The most common non-toxic alcohol substances were ethanol (24.9 percent) or an unknown drug (17.5 percent). Acidosis, increased creatinine concentration, anion gap, and osmolal gap, and kidney failure were coded in a lower proportion of toxic alcohol exposures than non-toxic alcohol exposures (P < 0.001). DISCUSSION: The inability to provide rapid clinical confirmation of toxic alcohol poisoning results in the empiric administration of fomepizole to many patients who will ultimately have other diagnoses. Although fomepizole is relative well tolerated we estimated that this practice costs between $1.5 to $2.5 million. The major limitations of this work include the biases associated with retrospective record review, and the inability to confirm the exposures which may have resulted in allocation error. CONCLUSION: Most fomepizole use was for a presumed toxic alcohol. This recently shifted to greater use in likely non-toxic alcohol poisoning. Key difference between the groups suggest fomepizole administration was likely due to the difficulty in diagnosis of toxic alcohol poisoning along with the efficacy and safety of fomepizole. Increased toxic alcohol laboratory testing availability could improve timely diagnosis, reserving fomepizole use for toxic alcohol poisoning.

Biodegradable poly(ethylene glycol-glycerol-itaconate-sebacate) copolyester elastomer with significantly reinforced mechanical properties by in-situ construction of bacterial cellulose interpenetrating network.

To address the concern that biodegradable elastomers are environmental-friendly but usually associated with poor properties for practical utilization, we report a star-crosslinked poly(ethylene glycol-glycerol-itaconate-sebacate) (PEGIS) elastomer synthesized by esterification, polycondensation and UV curing, and reinforced by bacterial cellulose (BC). The interpenetrating network of primary BC backbone and vulcanized elastomer is achieved by the "in-situ secondary network construction" strategy. With the well dispersion of BC without agglomeration, the mechanical properties of PEGIS are significantly enhanced in tensile strength, Young's modulus and elongation at break. The reinforcement strategy is demonstrated to be efficient and offers a route to the development of biodegradable elastomers for a variety of applications in the future.

Antiurolithiatic effects of Cassia fistula Lin. fruit extracts on ethylene glycol-induced nephrolithiasis in rats.

Urinary stones are a growing disease that results from pathological biomineralization. Cassia fistula Lin. is traditionally used to treat urinary stones. However, no scientific evidence is available to prove its antilithiatic effect. This study evaluates the antilithiatic potential of aqueous and ethanolic extract of Cassia fistula Lin. fruit (Cff) against calcium oxalate kidney stones. Forty-two male Wistar rats were divided into seven groups (n = 6/group): Group I (control), Group II (rats treated with ethylene glycol and ammonium chloride developed nephrolithiasis after 28 days), Group III (lithiatic rats receiving distilled water for 30 days), Group IV and V (lithiatic rats receiving aqueous extract of Cff at doses of 1 and 100 mg/kg body weight for 30 days, respectively) and Group VI and VII (lithiatic rats receiving ethanolic extract of Cff at doses of 1 and 100 mg/kg body weight for 30 days, respectively). Some parameters of urine and serum, and also renal oxidative stress and histopathology were used to determine the antilithiatic effect of aqueous and ethanolic extract of Cff. Therefore, the types of extracts of Cff improved abnormal levels of urine, serum, and renal oxidative stress and histopathology parameters. This antilithiatic effect of aqueous and ethanolic extracts of Cff, can be attributed to the anti-crystallization and antioxidant properties of the extracts and the ability to improve urine and serum biochemistry. RESEARCH HIGHLIGHTS: Ethylene glycol and ammonium chloride-induced urolithiasis, aggregation of calcium oxalate deposits, increase of some urinary and serum parameters, relative kidney weight, kidney size and MDA activity, decrease of some urinary parameters, relative body weight and SOD activity. Aqueous and ethanolic extracts of Cassia fistula Lin. lead to the treatment of urolithic rats by decreasing levels of urinary oxalate, phosphate, urea, serum urea, uric acid, creatinine, calcium, phosphate, MDA, kidney weight and kidney size, increasing levels of urinary calcium, creatinine, magnesium, citrate, body weight and SOD activity in the kidney, eliminating CaOx deposition (esp. ethanolic extract).

Elevated Osmolal Gap in a Case of Multiple Myeloma.

BACKGROUND: The estimated serum osmolality is a measurement of solutes in the blood, including sodium, glucose, and urea, but also includes ethanol and toxic alcohols (e.g., methanol, ethylene glycol, diethylene glycol, isopropyl alcohol, propylene glycol) when present. These rarely measured toxic alcohols can elevate the serum osmolality, giving the true measured osmolality. The difference between that and a calculated osmolality is the osmolal gap, which can be elevated in many clinical scenarios such as renal failure, ingestion of toxic alcohols, diabetic ketoacidosis, shock, and others. CASE REPORT: We report a patient with a history of alcohol use disorder who came to the Emergency Department with an abnormally elevated osmolal gap in the setting of altered mental status. The patient's increased osmolal gap was further investigated while he was promptly treated with fomepizole, thiamine, and urgent hemodialysis. WHY SHOULD AN EMERGENCY PHYSICIAN BE AWARE OF THIS?: We discuss the differential diagnosis for substances that increase the osmolal gap with respective ranges of elevation. This case demonstrates that although osmolal gap elevation is often attributed to the presence of toxic alcohols, other common etiologies may account for the gap, including acute renal failure and multiple myeloma.

Disposition of glycolic acid into the embryo following oral administration of ethylene glycol during placentation in the rat and rabbit.

In order to evaluate the role of the placenta in the etiology of ethylene glycol (EG) developmental toxicity, the distribution of EG and its main metabolites, glycolic acid (GA) and oxalic acid (OX), into the conceptus was determined at the beginning and completion of placentation in the rat and rabbit. Two groups (n = 28) of timed-pregnant Wistar rats were administered EG (1000 mg/kg bw/day, oral gavage) from gestation day (GD) 6 to either GD 11 or GD 16; similarly, two groups (n = 28) of timed-pregnant New Zealand White rabbits were administered EG from GD 6 to either GD 10 or GD 19. Four animals from each group were sacrificed at 1, 3, 6, 9, 12, 18, or 24 h after the final administration, and maternal blood, extraembryonic fluid, and embryonic tissue were removed for analysis of EG, GA, and OX. The three analytes were predominantly cleared from all compartments in both species within 24 h. Neither EG nor OX preferentially accumulated into the conceptus compartments, compared with the maternal blood, in either species. Critically, GA was preferentially accumulated from the maternal blood only into the rat embryo at GD 11, but not at GD 16 and not into the rabbit embryo at either GD 10 or GD 19. The accumulation of GA into the rat embryo, and its decline over the course of placentation, is discussed in relation to the expression of monocarboxylate transporter isoforms across the syncytiotrophoblast.

A mycofactocin-associated dehydrogenase is essential for ethylene glycol metabolism by Rhodococcus jostii RHA1.

Ethylene glycol is an industrially important diol in many manufacturing processes and a building block of polymers, such as poly(ethylene terephthalate). In this study, we found that a mycolic acid-containing bacterium Rhodococcus jostii RHA1 can grow with ethylene glycol as a sole source of carbon and energy. Deletion of a putative glycolate dehydrogenase gene (RHA1_ro03227) abolished growth with ethylene glycol, indicating that ethylene glycol is assimilated via glycolate in R. jostii RHA1. Transcriptome sequencing and gene deletion analyses revealed that a gene homologous to mycofactocin (MFT)-associated dehydrogenase (RHA1_ro06057), hereafter referred to as EgaA, is essential for ethylene glycol assimilation. Furthermore, egaA deletion also negatively affected the utilization of ethanol, 1-propanol, propylene glycol, and 1-butanol, suggesting that EgaA is involved in the utilization of various alcohols in R. jostii RHA1. Deletion of MFT biosynthetic genes abolished growth with ethylene glycol, indicating that MFT is the physiological electron acceptor of EgaA. Further genetic studies revealed that a putative aldehyde dehydrogenase (RHA1_ro06081) is a major aldehyde dehydrogenase in ethylene glycol metabolism by R. jostii RHA1. KEY POINTS: • Rhodococcus jostii RHA1 can assimilate ethylene glycol via glycolate • A mycofactocin-associated dehydrogenase is involved in the oxidation of ethylene glycol • An aldehyde dehydrogenase gene is important for the ethylene glycol assimilation.

Neurologic Complications in Critically Ill Patients with Toxic Alcohol Poisoning: A Multicenter Population-Based Cohort Study.

BACKGROUND: Toxic alcohol poisoning is regularly encountered in emergency departments and intensive care units (ICUs). Most patients present with an altered level of consciousness, but the subsequent course and spectrum of neurologic complications and outcomes is highly variable. METHODS: We performed a population-based, multicenter retrospective cohort study of critically ill patients with toxic alcohol poisoning admitted to ICUs in Alberta, Canada, between 2007 and 2019 to describe neurologic sequelae, including seizures, coma, neuroimaging abnormalities, persistent cognitive or visual impairment, and mortality. Multivariate analysis was performed to identify predictors of poor outcome. RESULTS: We identified 104 patients, including 55 (53%) with methanol ingestion, 36 (35%) with ethylene glycol ingestion, and 13 (13%) with isopropanol ingestion. In patients who underwent neuroimaging, abnormalities were detected in 9 of 24 (38%) with methanol toxicity, 5 of 20 (25%) with ethylene glycol toxicity, and 0 of 10 with isopropanol toxicity (p = 0.07). Basal ganglia were commonly involved with both methanol and ethylene glycol poisoning, but prominent subcortical involvement and restricted diffusion were observed only with methanol poisoning. The composite of death, persistent cognitive impairment, or visual loss occurred in 13 (24%) patients with methanol poisoning, compared with one (3%) with ethylene glycol poisoning and none with isopropanol poisoning (p = 0.006). Among patients with methanol toxicity, greater elevation of the anion gap and lower Glasgow Coma Scale score were independent predictors of poor outcome. No patient with an anion gap ≥ 28 at presentation had a favorable recovery. Progression to death by neurologic criteria occurred in 3 of 55 (5%) patients with methanol poisoning and in none with other toxic alcohols. CONCLUSIONS: Methanol overdose is the most common form of toxic alcohol poisoning to result in ICU admission. Poor neurologic outcomes may occur especially with methanol poisoning, with more than one in five patients dying or having persistent cognitive or visual impairment. A wide anion gap independently predicts poor outcome, emphasizing the importance of expeditious recognition and treatment.

Use of Antifreeze Protein from Tenebrio molitor (TmAFP) in Vitrification of In Vitro-Produced Bovine Embryos: An Ultrastructural Study.

The objective of this study was to evaluate the effects of different concentrations of antifreeze protein (AFP) extracted from the larva of the beetle, Tenebrio molitor (TmAFP), on vitrification of in vitro-produced bovine embryos. In vitro-produced blastocysts were divided into three experimental groups and vitrified using a cryotop. TmAFP was added to the equilibrium solution (ES) and vitrification solution (VS) at a concentration of 0 ng/mL (control), 500 ng/mL (500TmAFP), or 1000 ng/mL (1000TmAFP). Vitrification was carried out by first placing the blastocysts in ES for 2 minutes (7.5% ethylene glycol [EG] and 7.5% dimethyl sulfoxide [DMSO]). The blastocysts were then transferred to VS (15% EG and 15% DMSO) and promptly deposited on a cryotop stem and submerged in liquid nitrogen. Warming was carried out in three steps with decreasing sucrose concentrations. After warming, the blast cells were cultured for 24 hours for subsequent survival analysis and ultrastructural evaluation. There was a significant difference in the survival rate and expansion in the 500TmAFP group compared with the other groups. The ultrastructural analysis revealed intracellular lesions in all vitrified embryos; however, the embryos of the 500TmAFP and 1000TmAFP groups showed fewer cytoplasmic lesions compared with the control group. Taken together, addition of TmAFP can mitigate cellular changes that involve organelles and cellular components essential for proper functioning and improve the viability of warmed and vitrified in vitro-produced bovine embryos.

Mild Quantitative One Step Removal of Macrophages from Cocultures with Human Umbilical Vein Endothelial Cells Using Thermoresponsive Poly(Di(Ethylene Glycol)Methyl Ether Methacrylate) Brushes.

The authors report on a mild, label-free, and fast method for the separation of human umbilical vein endothelial cells (HUVEC), which are relevant cells, whose use is not limited to studies of endothelial dysfunction, from cocultures with macrophages to afford HUVEC in ≈100% purity. Poly(di(ethylene glycol)methyl ether methacrylate) (PDEGMA) brushes with a dry thickness of (5 ± 1) nm afford the highly effective one-step separation by selective HUVEC detachment, which is based on the brushes' thermoresponsive behavior. Below the thermal transition at 32 °C the brushes swells and desorbs attached proteins, resulting in markedly decreased cell adhesion. Specifically, HUVEC and macrophages, which are differentiated from THP-1 monocytes, are seeded and attached to PDEGMA brushes at 37°C. After decreasing the temperature to 22°C, HUVEC shows a decrease in their cell area, while the macrophages are not markedly affected by the temperature change. After mild flushing with a cell culture medium, the HUVEC can be released from the surface and reseeded again with ≈100% purity on a new surface. With this selective cell separation and removal method, it is possible to separate and thereby purify HUVEC from macrophages without the use of any releasing reagent or expensive labels, such as antibodies.

Emerging progressive atypical acute kidney injury in young children linked to ethylene glycol and diethylene glycol intoxication.

BACKGROUND: There had been a sudden surge of unusually severe and rapidly progressing acute kidney injury (AKI) incidence in Indonesia since August 2022 which did not correspond to the rise of COVID-19 incidence. We suspected this was related to ethylene glycol (EG) and diethylene glycol (DEG) intoxication. This study is aimed at describing the clinical and laboratory characteristics of AKI related to D(EG) intoxication in order to spread awareness of the possibility of intoxication in cases of rapidly progressing AKI with unknown etiology. METHODS: We conducted a cross-sectional study by collecting secondary data from the pediatric AKI registry at a national referral hospital in Jakarta, Indonesia. Data on children admitted from January to November 2022 with diagnosis of stage 3 AKI based on KDIGO criteria were included. Data regarding demographics, symptoms prior to anuria, laboratory results, infection panel including COVID-19 status, treatment administered, and mortality were analyzed. RESULTS: Sixteen patients tested positive for EG and DEG, all with history of consuming syrup-based medications. High anion gap metabolic acidosis was observed in majority of patients with mean pH 7.33 ± 0.07 and mean anion gap 15.6 ± 7.8 mEq/L. No patient had high osmolal gap (mean osmolal gap 3.46 ± 4.68). One deceased patient, who had kidney biopsy performed, showed severe damage and calcium oxalate crystals in the kidney tissue. Mortality was recorded in six patients (37.5%). CONCLUSION: Careful history taking of patient's clinical course, including consumption of syrup-based medications and laboratory findings, might aid clinicians to establish a working diagnosis of D(EG) intoxication without needing to wait for blood toxicology test. Early diagnosis and therapy are crucial to prevent substantial mortality.

Valorization of single-carbon chemicals by using carboligases as key enzymes.

Single-carbon (C1) biorefinery plays a key role in the consumption of global greenhouse gases and a circular carbon economy. Thereby, we have focused on the valorization of C1 compounds (e.g. methanol, formaldehyde, and formate) into multicarbon products, including bioplastic monomers, glycolate, and ethylene glycol. For instance, methanol, derived from the oxidation of CH4, can be converted into glycolate, ethylene glycol, or erythrulose via formaldehyde and glycolaldehyde, employing C1 and/or C2 carboligases as essential enzymes. Escherichia coli was engineered to convert formate, produced from CO via CO2 or from CO2 directly, into glycolate. Recent progress in the design of biotransformation pathways, enzyme discovery, and engineering, as well as whole-cell biocatalyst engineering for C1 biorefinery, was addressed in this review.

Minding the osmol gap: a sentinel event and subsequent laboratory investigation.

INTRODUCTION: Many hospitals are unable to determine toxic alcohol concentrations in a clinically meaningful time frame. Thus, clinicians use surrogate markers when evaluating potentially poisoned patients. INDEX CASE: A patient presented after an intentional antifreeze (ethylene glycol) ingestion with an osmol gap of -10.6 that remained stable one hour later. Further investigation revealed that the serum osmolality was calculated and not measured. The true osmol gap was 16.4, which correlated to a measured ethylene glycol concentration of 808 mg/L (80.8 mg/dL, 13.0 mmol/L). SURVEY: A telephone survey of hospital laboratories in our catchment area was performed to investigate the potential for similar events. RESULTS: Thirty-eight (47 percent) hospitals responded. No laboratories were able to test for toxic alcohols. One hospital (2.6 percent) reported routinely calculating osmolality based on chemistries, while two hospitals (5.3 percent) reported scenarios in which this might occur. Thirty-five (92.1 percent) hospitals could directly measure osmolality. Two hospitals (5.3 percent) were reliant on outside laboratories for osmolality measurement. LIMITATIONS: The 47 percent response rate and one geographic area are significant limitations. DISCUSSION: Over 10 percent of hospitals that responded could have significant difficulty assessing patients with toxic alcohol ingestion. CONCLUSIONS: Until the standard of rapidly obtaining toxic alcohol concentrations is broadly implemented, we recommend that policies and procedures be put in place to minimize errors associated with the determination of the osmol gap.

The cryoprotective effect of Guar gum co-supplemented with ethylene glycol and glycerol in Simmental bull semen.

Sperm cryopreservation often reduces sperm quality by forming of intra- and extracellular ice crystals. Various compounds widely used to counteract this effect. The guar gum was considered as an extracellular cryoprotective substance. The present study evaluated the impact of the co-supplementation of guar gum with ethylene glycol or glycerol in the cryopreservation of bull sperm. Four ejaculates from 4 bulls were pooled and divided into ten groups consisting of 4 controls (glycerol 6%, ethylene glycol 6%, glycerol 3.5%, and ethylene glycol 3.5%, and six treatment groups including guar gum in 0.001% and 0.002% alone and or co-supplemented either with 3.5% glycerol or 3.5% ethylene glycol and frozen in liquid nitrogen. The sperm motility, viability, plasma membrane and DNA integrity, apoptotic-like changes, antioxidant capacity (TAC), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities evaluated. The groups contained 3.5% glycerol + 0.001% guar gum, 3.5% ethylene glycol + 0.001% guar gum, and 0.001% guar gum alone showed higher values for live sperm, antioxidant enzymes, membrane integrity, mitochondrial membrane potential (MMP), fertilization, cleavage, and blastocyst rates; and lower values for apoptotic-like changes, H2O2 level, and DNA damage than the control groups. In conclusion, adding guar gum to the bull sperm diluent either alone or combined with glycerol or ethylene glycol ameliorated sperm viability and kinematic parameters and antioxidant capacity while reducing DNA damage and apoptotic-like changes. Guar gum also has improved embryo development. Due to its cost-effectiveness and physicochemical properties, guar gum is a promising supplement for bull sperm cryopreservation.

Next-generation feedstocks methanol and ethylene glycol and their potential in industrial biotechnology.

Microbial fermentation processes are expected to play an important role in reducing dependence on fossil-based raw materials for the production of everyday chemicals. In order to meet the growing demand for biotechnological products in the future, alternative carbon sources that do not compete with human nutrition must be exploited. The chemical conversion of the industrially emitted greenhouse gas CO2 into microbially utilizable platform chemicals such as methanol represents a sustainable strategy for the utilization of an abundant carbon source and has attracted enormous scientific interest in recent years. A relatively new approach is the microbial synthesis of products from the C2-compound ethylene glycol, which can also be synthesized from CO2 and non-edible biomass and, in addition, can be recovered from plastic waste. Here we summarize the main chemical routes for the synthesis of methanol and ethylene glycol from sustainable resources and give an overview of recent metabolic engineering work for establishing natural and synthetic microbial assimilation pathways. The different metabolic routes for C1 and C2 alcohol-dependent bioconversions were compared in terms of their theoretical maximum yields and their oxygen requirements for a wide range of value-added products. Assessment of the process engineering challenges for methanol and ethylene glycol-based fermentations underscores the theoretical advantages of new synthetic metabolic routes and advocates greater consideration of ethylene glycol, a C2 substrate that has received comparatively little attention to date.

Determination of cell membrane permeability coefficients: Comparison of models in the case of oocytes.

Values of cell membranes permeability coefficients for water and molecules of cryoprotective agents (CPAs) are the necessary characteristics for developing physical-mathematical models describing mass transfer processes through cell membranes in order to predict optimal cell cooling rates. We carried out a comparative analysis of the permeability coefficients of mouse oocyte membranes for molecules of water, ethylene glycol (EG), propane-1,2-diol (1,2-PD) and dimethyl sulfoxide (Me2SO), determined by applying the classical Kedem-Katchalsky model, which considers only the penetration of non-electrolyte molecules (water and CPA) through the membrane, and the model developed by us, which takes into account the transmembrane transfer of ions and the associated changes in the transmembrane electric potential. We shown that calculations based on the developed modified model provide lower values of the permeability coefficients of the oocyte membrane for water and CPA molecules. What is important that the obtained by our modified model permeability coefficients for water molecules do not depend on the type of cryoprotectant, while the application of the classical model both in our studies and works of other authors always gave different values of these coefficients in solutions with different cryoprotectants. Our modified model also makes it possible to determine the dynamics of the transmembrane electric potential of the cell under the conditions of transmembrane mass transfer and the duration of the membrane being influenced by the changes in electric potential, that is a parameter that can directly affect the viability of cells.