Heterologous expression of MiHAK14 enhances plant tolerance to K+ deficiency and salinity stresses in Arabidopsis

As one of the most abundant ions in cells, potassium (K+) is closely related to plant growth and development and contributes to plant tolerance to various abiotic stresses. However molecular mechanisms towards K+ uptake and transport are unclear in tropic fruit trees. In this study, 18 KT/HAK/KUP family genes (MiHAKs) were isolated and characterized in mango. Results showed that MiHAKs were unevenly expressed in distinct tissues and were differentially responded to K+ depletion, PEG, and NaCl stresses in roots, in which K+ depletion and PEG treatment significantly enhanced while NaCl treatment mainly reduced responsive MiHAK genes. In particular, MiHAK14 was the most abundant KT/HAK/KUP family gene in mango, especially in roots. Functional complementation in TK2420 mutant revealed that MiHAK14 could uptake external K+. Moreover, overexpression of MiHAK14 in Arabidopsis enhanced plant tolerance to K+ depletion and NaCl stresses with strengthened K+ nutritional status and ROS scavenging ability. This study provides molecular basis for further functional studies of KT/HAK/KUP transporters in tropic fruit trees, and favorably demonstrates the essentiality of K+ homeostasis in plant tolerance to abiotic stresses, including K+ deficiency and NaCl stress.

Structural Monitoring of a Large Archaeological Wooden Structure in Real Time, Post PEG Treatment

Large archaeological wooden structures are potentially at risk of structural failure through deformation and cracking over time if they are left untreated and their structural health is not maintained. This could be in part due to, for example, the shrinkage of waterlogged wood as it dries, or time-dependent creep processes. These dimensional changes are accompanied by associated stresses. However, there are few studies analysing the movement of large wooden structures in real time as they dry, particularly after their conservation treatment. This paper follows the structural monitoring of the Mary Rose from after the conservation treatment, where it was sprayed with polyethylene glycol, through to the ship’s air-drying process and beyond to assess the effects that drying has had on the displacement of the timbers. A laser-based target system was used to collect displacement data between 2013 and 2020 and the data showed a significant slowing of displacement as the drying reached an equilibrium.

Heterologous Expression of ZmNF-YA12 Confers Tolerance to Drought and Salt Stress in Arabidopsis

Drought and salinity are serious environmental factors limiting the growth and productivity of plants worldwide. Therefore, it is necessary to develop ways to improve drought and salinity stress tolerance in plants. In this study, a drought-responsive nuclear factor Y subunit A gene, ZmNF-YA12, was cloned from maize. qPCR revealed ZmNF-YA12 transcript in all vegetative and reproductive tissues, with higher levels in young roots. Expression analyses of maize revealed that ZmNF-YA12 was induced by abscisic acid (ABA), jasmonic acid (JA), and abiotic stresses, including dehydration, high salinity, cold, and polyethylene glycol (PEG) treatment. The heterologous expression of ZmNF-YA12 in Arabidopsis plants resulted in increased root length and better plant growth than in wild-type (WT) plants under conditions of mannitol, salt, and JA stress on 1/2 MS medium. Transgenic Arabidopsis showed improved tolerance to drought and salt stresses in soil, and higher proline content and lower malondialdehyde (MDA) content than WT controls. The transgenic plants also maintained higher peroxidase (POD) activities than WT plants under conditions of NaCl stress. A yeast two-hybrid experiment demonstrated that ZmNF-YA12 interacted with ZmNF-YC1 and ZmNF-YC15. Moreover, the transcript levels of stress-responsive genes (RD29A, RD29B, RAB18, and RD22) were markedly increased in transgenic lines under conditions of drought and salt stress. These observations suggested that the ZmNF-YA12 gene confers drought and salt stress tolerance, and has potential applications in molecular breeding with maintenance of production under conditions of stress.

Differences in Distribution and Biological Effects of F3O4@PEG Nanoparticles in Normotensive and Hypertensive Rats—Focus on Vascular Function and Liver

We investigate the distribution and biological effects of polyethylene glycol (PEG)-coated magnetite (Fe3O4@PEG) nanoparticles (~30 nm core size, ~51 nm hydrodynamic size, 2 mg Fe/kg/day, intravenously, for two days) in the aorta and liver of Wistar–Kyoto (WKY) and spontaneously hypertensive rats (SHR). Fe3O4@PEG had no effect on open-field behaviour but reduced the blood pressure (BP) of Fe3O4@PEG-treated SHR (SHRu) significantly, compared to both Fe3O4@PEG-treated WKY (WKYu) and saline-treated control SHR (SHRc). The Fe3O4@PEG content was significantly elevated in the aorta and liver of SHRu vs. WKYu. Nitric oxide synthase (NOS) activity was unaltered in the aorta, but significantly increased in the liver of SHRu vs. SHRc. In the aorta, Fe3O4@PEG treatment increased eNOS, iNOS, NRF2, and DMT1 gene expression (considered main effects). In the liver, Fe3O4@PEG significantly elevated eNOS and iNOS gene expression in SHRu vs. SHRc, as well as DMT1 and FTH1 gene expression (considered main effects). Noradrenaline-induced contractions of the femoral arteries were elevated, while endothelium-dependent contractions were reduced in SHRu vs. SHRc. No differences were found in these parameters in WKY rats. In conclusion, the results indicated that the altered haemodynamics in SHR affect the tissue distribution and selected biological effects of Fe3O4@PEG in the vasculature and liver, suggesting that caution should be taken when using iron oxide nanoparticles in hypertensive subjects.

PEG-induced Drought Stress in Plants: A Review

Drought is one of the most commonly faced significant factors that impede plant productivity and growth. Especially in the context of agriculture, crop productivity and sustainable farming are most adversely affected by water shortage conditions caused by drought. Plants have several adaptations to respond to such conditions, both physiological as well as metabolic. An understanding of these adaptations is essential to develop a biotechnological solution to the problem of drought-related crop losses across the globe. This review addresses the various changes that plants undergo when subjected PEG (Polyethylene glycol). Various drought stress markers are associated with PEG induced stress are expressed in the biochemistry, physiology, photosynthesis and metabolism of the plant. Therefore PEG treatment in plants are considered as an effective model for drought stress investigation.

Effect of Polyethylene Glycol Treatment on Acetic Acid Emissions from Wood

Acetic acid is known to be emitted from sound wood and can accelerate damage to heritage materials, particularly metals. However, few studies have investigated the extent of acetic acid emissions from archaeological wood. This research utilised Solid-Phase-Micro-Extraction (SPME) GC–MS and lead coupon corrosion to identify volatile emissions from polyethylene glycol (PEG)-treated archaeological wood from the Mary Rose collection and assess if they could cause accelerated damage. In addition, the effect of PEG treatment on acetic acid emissions was investigated using sound wood samples. For sound wood, the PEG treatment acted as a barrier to acetic acid emissions, with higher-molecular-weight PEGs preventing more emissions. Archaeological wood, despite its age and high-molecular-weight PEG treatment, still emitted detectable concentrations of acetic acid. Moreover, they emitted a wider array of compounds compared to sound wood, including carbon disulphide. Like sound wood, when the archaeological wood samples were in a sealed environment with lead coupons, they caused accelerated corrosion to lead. This evidences that archaeological wood can emit high enough concentrations of volatile compounds to cause damage and further investigation should be performed to evaluate if this can occur inside museum display cases.

Efficacy and Safety of Pegcetacoplan Treatment in Complement-Inhibitor Naïve Patients with Paroxysmal Nocturnal Hemoglobinuria: Results from the Phase 3 Prince Study

Background: Paroxysmal nocturnal hemoglobinuria (PNH) is a rare and life-threatening disease characterized by hemolysis and thrombosis. Many patients with PNH use C5-inhibitors (i.e., eculizumab/ravulizumab) to control their symptoms. Although C5-inhibition prevents intravascular hemolysis (IVH), it fails to prevent extravascular hemolysis (EVH). Because of persistent EVH, up to 72% of eculizumab-treated patients remain anemic, and up to 36% require at least one transfusion per year. Pegcetacoplan (PEG), a C3-inhibitor recently approved by the US FDA to treat adults with PNH, controls IVH and prevents EVH. Studies of PEG treatment in patients with PNH that remained anemic despite eculizumab treatment demonstrated that PEG was superior to eculizumab in achieving improvements in hemoglobin (Hb) levels (Hillmen P, et al., N Engl J Med, 2021 384 (11):1028-1037). Additionally, two early phase open-label trials demonstrated the efficacy of PEG in complement-inhibitor naïve patients with PNH (Wong RS, et al., Blood, 2020 136 [Supplement 1]). Aims: To present results from the Phase 3 PRINCE study (NCT04085601), a multicenter, randomized, open-label, controlled study evaluating the efficacy and safety of PEG compared to standard of care (SOC; excluding complement-inhibitors) in complement-inhibitor naïve patients with PNH. Methods: Fifty-three adult (≥18 years old), complement-inhibitor naïve (no complement-inhibitor treatment [i.e., eculizumab/ravulizumab] within 3 months prior to screening) patients with PNH and Hb levels below the lower limits of normal (males: ≤13.6 g/dL; females: ≤12.0 g/dL), and lactate dehydrogenase (LDH) levels ≥1.5 times the upper limit of normal (1.5x ULN; ≥339 U/L) were enrolled. Patients were randomized 2:1 to receive PEG (1080 mg subcutaneously twice weekly [n=35]) or SOC (excluding complement-inhibitors eculizumab/ravulizumab [n=18]) through Week 26. Patients on SOC had the option to switch to the PEG group if their Hb decreased by ≥2 g/dL from baseline. Co-primary endpoints were Hb stabilization (avoidance of a >1 g/dL decrease in Hb levels in the absence of transfusions) and change from baseline (CFB) in LDH level from baseline to Week 26. Secondary endpoints included CFB in Hb levels, transfusion avoidance (defined as the proportion of subjects who did not require a transfusion through Week 26), and the incidence of adverse events (AEs). Statistical analyses were performed using the Cochran-Mantel-Haenszel test and ANCOVA model. Results: PEG was superior to SOC in both co-primary endpoints. Hb stabilization was achieved by 85.7% (n=30) of PEG-treated patients and 0.0% of SOC patients through Week 26 (p<0.0001). PEG-treated patients demonstrated superior reductions in mean LDH levels from baseline to Week 26 compared to SOC patients (least-squares mean CFB: PEG, -1870.5 U/L; SOC, -400.1 U/L; p<0.0001), and mean LDH levels in PEG-treated patients at Week 26 (mean level: 204.6 U/L) were below the ULN for LDH (226.0 U/L). PEG was also superior to SOC in the secondary endpoints: mean CFB in Hb levels (least-squares mean CFB: PEG, 2.9 g/dL; SOC, 0.3 g/dL; p=0.0019; Week 26 mean Hb: PEG, 12.8 g/dL; SOC, 9.8 g/dL) (Figure) and transfusion avoidance (PEG, 91.4%, n=32; SOC, 5.6%, n=1; p<0.0001). Serious AEs were reported by 8.7% (n=4) of PEG-treated patients and 16.7% (n=3) of SOC patients through Week 26. Two deaths (PEG, 2.9%, n=1, septic shock related to medullary aplasia; SOC, 5.6%, n=1, respiratory failure), both deemed unrelated to treatment, occurred. No events of meningitis or thrombosis were reported in either group. The most common AEs reported during the study were injection site reaction (PEG, 30.4%, n=14; SOC, 0.0%), hypokalemia (PEG, 13.0%, n=6; SOC, 11.1%, n=2), and fever (PEG, 8.7%, n=4; SOC, 0.0%). There were no AEs leading to discontinuation of PEG. Conclusions: Patients with PNH that were naïve to complement-inhibitor treatment demonstrated meaningful hematological and clinical improvements following 26 weeks of PEG treatment. The safety profile of PEG was similar to previous study results and represent a favorable risk-benefit profile. These results provide evidence for the safety and efficacy of PEG treatment in complement-inhibitor naïve patients with PNH. Figure 1 Figure 1. Disclosures Wong: Roche: Consultancy, Honoraria, Research Funding, Speakers Bureau; Apellis Pharmaceuticals: Research Funding, Speakers Bureau; Alexion: Consultancy, Honoraria, Research Funding, Speakers Bureau. Al-Adhami: Apellis Pharmaceuticals: Current Employment. Ajayi: Apellis Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Alvarenga: Apellis Pharmaceuticals: Consultancy. Deschatelets: Apellis Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company, Membership on an entity's Board of Directors or advisory committees, Patents & Royalties. Francois: Apellis Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company. Grossi: Apellis Pharmaceuticals: Current Employment, Current equity holder in publicly-traded company.

Drought Stress Study on Nicotiana tabacum L., “Baladi”, an In Vitro Experimental Model

Crops drought tolerance is a trait of outmost importance for agriculture especially today when climate change is affecting more the production for food and feed. The scope of this article is to evaluate in vitro drought stress response of Nicotiana tabacum L., “Baladi”. The experiment was set up for four successive stages starting with in vitro seedling development, hypocotyl cultivation, three generations of micropropagation, pre-acclimatization and acclimatization. The effect of abscisic acid (ABA) and/or polyethylene-glycol 6000 (PEG) on tobacco hypocotyl caulogenesis and micropropagation were investigated. Superoxide-dismutases (SODs) and peroxidases (POXs) are more active and different isoforms patterns have been identified compared to the control for cualogenesis. A decrease of internodes length and a higher shoots multiplication rate were observed. However, under PEG treatment plantlets expressed hyperhydration and ceased rooting. Pre-treatments effects study of ABA and/or PEG were finalized in acclimatization phase for 18 tobacco clones. A summary of our results revealed that ABA and/or PEG induce among others a higher oxidative stress compared to the control in the first stage that is not maintained for all clones until acclimatization. Certain clones expressed a lower SOD activity compared to the control during acclimatization but maintaining higher POX activity.

Effects of Drought and Salt Stress on Activities of Antioxidant Protective Enzymes and Expression of Stress Genes in Alfalfa (Medicago sativa L.) Seedlings

Drought and salt are main environmental factors that affect the growth, development, productivity and distribution of plants of plants. Alfalfa has a strong ability of early and salt resistance. In this work, the varieties Xinjiang Daye was used as material, the effects of drought (simulated with PEG, polyethylene glycol-6000) and salt stress (with NaCl solution) on the antioxidant capacity of alfalfa seedlings and stress resistance genes was studied, to select alfalfa varieties with strong resistance and study its functional principle of resistance related genes. The results showed that with the increase of drought stress, the contents of H2O2, O2−, MDA increased by 323, 247 and 235 (15% PEG treatment). The activities of SOD, CAT and APX increased by 18.01, 15.56 and 587% (15% PEG treatment), respectively. The expression of drought resistance genes increased significantly. With the increase in NaCl stress, the activities of SOD, cat, pod and APX increased by 132.14, 315.60, 102.78 and 27.61%, respectively. The expression of two genes related to salt stress increased significantly. In conclusion, alfalfa leaves have good survival ability under high stress, and the activities of antioxidant enzymes and the expression of related genes have adaptive changes under drought and salt stress.

Polyethylene Glycol Treatment for Peripheral Nerve Repair in Preclinical Models

Introduction: Peripheral nerve injuries commonly result from trauma and can lead to devastating loss of sensory and motor function. A novel strategy to improve peripheral nerve regeneration is a chemical fusogen known as polyethylene glycol (PEG). Several animal studies have illustrated PEG’s potential to help prevent axon loss after peripheral nerve injury. However, the relative rate of success and potential complications of these studies have not been definitively shown in the literature. The purpose of this systematic review is to evaluate the literature regarding the success of PEG adjunct treatment after peripheral nerve injury in preclinical models. Materials and Methods: The MEDLINE database was queried using the PubMed search engine with the following keywords and phrases: “polyethylene glycol” OR “PEG” AND “nerve” AND “fusion”. All resulting articles were screened by two reviewers. Animal type, nerve type, injury type, type(s) of analyses, and overall superiority of outcomes were assessed. Results: One-hundred and seventy-nine articles were identified, and thirteen studies remained after the application of inclusion and exclusion criteria. Twelve of the thirteen studies utilized rats as the preclinical model, while one utilized a guinea pig. Superiority of peripheral nerve repair outcomes with adjunct PEG treatment compared to a control group was reported in eleven of thirteen studies. Conclusions: The majority of studies reported positive outcomes when using PEG; this indicates that PEG treatment has the potential to enhance peripheral nerve regeneration after injury. However, the results of some of these studies indicated several uncertainties that need to be addressed in future studies. These preclinical models may help guide clinicians regarding the use of PEG treatment in peripheral nerve repair.