Nitric Oxide and Abscisic Acid Mediate Heat Stress Tolerance through Regulation of Osmolytes and Antioxidants to Protect Photosynthesis and Growth in Wheat Plants

Nitric oxide (NO) and abscisic acid (ABA) play a significant role to combat abiotic stress. Application of 100 µM sodium nitroprusside (SNP, NO donor) or ABA alleviated heat stress effects on photosynthesis and growth of wheat (Triticum aestivum L.) plants exposed to 40 °C for 6 h every day for 15 days. We have shown that ABA and NO synergistically interact to reduce the heat stress effects on photosynthesis and growth via reducing the content of H2O2 and thiobarbituric acid reactive substances (TBARS), as well as maximizing osmolytes production and the activity and expression of antioxidant enzymes. The inhibition of NO and ABA using c-PTIO (2-4 carboxy-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide) and fluridone (Flu), respectively, reduced the osmolyte and antioxidant metabolism and heat stress tolerance. The inhibition of NO significantly reduced the ABA-induced osmolytes and antioxidant metabolism, exhibiting that the function of ABA in the alleviation of heat stress was NO dependent and can be enhanced with NO supplementation.Thus, regulating the activity and expression of antioxidant enzymes together with osmolytes production could act as a possible strategy for heat tolerance

The crosstalk of melatonin and hydrogen sulfide determines photosynthetic performance by regulation of carbohydrate metabolism in wheat under heat stress

Photosynthesis is a pivotal process that determines the synthesis of carbohydrates re-quired for sustaining growth under normal or stress situation. Stress exposure reduces the photosynthetic potential owing to the excess synthesis of reactive oxygen species that disturb the proper functioning of photosynthetic apparatus. This decreased photosynthesis is associated with dis-turbances in carbohydrate metabolism resulting in reduced growth under stress. We evaluated the importance of melatonin in reducing heat stress‐induced severity in wheat (Triticum aestivum L.) plants. The plants were subjected to 25 °C (optimum temperature) or 40 °C (heat stress) for 15 days at 6 h time duration and then developed the plants for 30 days. Heat stress led to oxidative stress with increased production of thiobarbituric acid reactive substances (TBARS) and hydrogen peroxide (H2O2) content and reduced accrual of total soluble sugars, starch and carbohydrate metabolism enzymes which were reflected in reduced photosynthesis. Application of melatonin not only reduced oxidative stress through lowering TBARS and H2O2 content,augmenting the activity of antioxidative enzymes but also increased the photosynthesis in plant and carbohydrate metabolism that was needed to provide energy and carbon skeleton to the developing plant under stress. However, the increase in these parameters with melatonin was mediated via hydrogen sulfide (H2S), as the inhibition of H2S by hypotaurine (HT; H2S scavenger) reversed the ameliorative effect of melatonin. This suggests a crosstalk of melatonin and H2S in protecting heat stress‐induced photosynthetic inhibition via regulation of carbohydrate metabolism

Ethylene and sulfur coordinately modulate the antioxidant system and ABA accumulation in mustard plants under salt stress

This study explored the interactive effect of ethephon (2-chloroethyl phosphonic acid; an ethylene source) and sulfur (S) in regulating the antioxidant system and ABA content and in maintaining stomatal responses, chloroplast structure, and photosynthetic performance of mustard plants (Brassica juncea L. Czern.) grown under 100 mM NaCl stress. The treatment of ethephon (200 µL L−1) and S (200 mg S kg−1 soil) together markedly improved the activity of enzymatic and non-enzymatic components of the ascorbate-glutathione (AsA-GSH) cycle, resulting in declined oxida-tive stress through lesser content of sodium (Na+) ion and hydrogen peroxide (H2O2) in salt-stressed plants. These changes promoted the development of chloroplast thylakoids and photosynthetic performance under salt stress. Ethephon + S also reduced abscisic acid (ABA) accumulation in guard cell, leading to maximal stomatal conductance under salt stress. The inhibition of ethylene action by norbornadiene (NBD) in salt-plus non-stressed treated plants increased ABA and H2O2 contents, and reduced stomatal opening, suggesting the involvement of ethephon and S in regulating sto-matal conductance. These findings suggest that ethephon and S modulate antioxidant system and ABA accumulation in guard cells, controlling stomatal conductance, and the structure and efficiency of the photosynthetic apparatus in plants under salt stress

Promising anti-microbial effect of apple vinegar as a natural decolonizing agent in healthcare workers

Introduction: Colonized Healthcare workers (HCWs) are an essential reservoir of nosocomial infections. This study aims to determine the prevalence of methicillin-resistant Staphylococcus aureus (MRSA) carriage rate among HCWs, to evaluate at Fayoum University Hospital the susceptibility of isolates to mupirocin and Chlorhexidine and to investigate the antimicrobial effect of different vinegars on MRSA as a natural decolonizing agent. Methods: Nasal and hand swabs were collected from 124 HCWs at Fayoum University Surgical Hospital. Isolates were identified using the standard microbiological methods. Susceptibilities to mupirocin and Chlorhexidine were determined by disk diffusion and broth micro-dilution. Screening antimicrobial effect of commercial vinegars was determined by agar well-diffusion method and microdilution method. Results: About one tenth 11.3% (14/124) of HCWs showed nasal carriage of MRSA. Workers were the predominant carriers (P = 0.013). The overall non-nasal carriage rate of MRSA was 6.5% (8/124). Among MRSA isolates Low-level Mupirocin resistance (LLMR) showed in (36.4%, 8/22). MICs ranged from 0.25 to 32 μg/ml. Also, (13.6 %, 3/22) showed Chlorhexidine resistance, MICs ranged from 0.039 to 5 μg/ml. Apple vinegar showed the highest susceptibility among vinegars (p < 0.0001) with MIC values varied from 0.058 to 1.87 μg/ml Discussion: The emergence of mupirocin (36.4%) and Chlorhexidine (13.6%) resistant Staphylococcus aureus among HCWs should be of excessive concern. Apple vinegar has a promising antimicrobial effect against MRSA isolates and could be used as a decolonizing agent

Effects of Thiamethoxam on Vespula Germanica (F.) (Hymenoptera: Vespidae)

Damage of pesticides used in agriculture on non-target organisms (except honey bees) is not sufficiently considered and neglected. Studies showed that wild bees, like honey bees, were also affected by pesticides. Wild bee species should also be protected because of their importance in pollination and biological control and also in order to protect biodiversity. Effects of pesticides on wild bees should be investigated without delay and precautions should be taken to protect the generations of wildlife. In addition, while increasing the agricultural areas, habitat for wild pollinators should be established.In this study, effect of Thiamethoxam, an agriculturally active agent in the neonicotinoid group, commonly used in agriculture fields, on the European wasp (Vespula germanica) was investigated. For this purpose, 2 molar carnation-flavored syrup in a petri dish was placed in a field where wild bees are frequent, and wild bees had got accustomed there. Trial doses were prepared with thiamethoxam dose commonly used in agricultural areas (15 ml/100 L water) and 50% dilutions of this dose (15.00, 7.50, 3.75, 1.87, 0.93, 0.46, 0.23, 0.12, 0.06 ml/100 L water) and fed in 2 molar syrup. Those who returned to the carnation petri dish after feeding were recorded at the 1st, 4th and 24th hours.At the end of the study, bees fed with 15.00, 7.50, and 3.75 ml / 100 L doses of the pesticide all died. One hour after pesticide ingestion, 84.73% of the control group and 13.33% of the bees fed with 1.87 ml / 100L dose, were alive and returned to the syrup petri dish

Tamoxifen for treatment of abnormal uterine bleeding in etonorgstrel implant users: a randomized clinical trial

Background: The current study aims to compare the use of tamoxifen and oral contraceptive pills in women using implanon and complain with irregular uterine bleeding.Methods: Women attended family planning clinic using implanon presented by bleeding were invited to participate in the study. They were randomized into two groups: Group A: 100 women received Tamoxifen 10 mg twice daily for 10 days taken at the onset of an episode of bleeding or spotting episode. Group B: 100 women received Combined oral contraceptive pills (microcept) once daily for 21 days take at the onset of an episode of bleeding or spotting episode.Results: No difference regarding the baseline criteria of both groups. No difference between both groups regarding the duration of irregular bleeding in the implanon users (p=0.090). Additionally, the number of bleeding days and spotting in the last month was similar in both groups (p=0.554). The percentage of women who stopped bleeding during the period of treatment is 84% in the tamoxifen group and 92% in the COCs group, but the COCs needs longer treatment time, where the mean of days required to stop bleeding is 5.03±1.8 days in the tamoxifen group and 6.5±2.5 in the COCs group. Headache and nausea were the most prominent adverse effects found in the COCs group (p=0.000).Conclusions: Oral administration of tamoxifen 10 mg twice daily for 10 days is effective on stopping bleeding attacks in implanon users

Salicylic acid increases photosynthesis of drought grown mustard plants effectively with sufficient-N via regulation of ethylene, abscisic acid, and nitrogen-use efficiency

An essential approach to reduce drought in plants is to maximize the use of most limited available resources. The increase in water-use efficiency (WUE) is important to maximally utilize the available water to increase photosynthesis and growth of plants under water-deficit stress. Both WUE and photosynthetic nitrogen-use efficiency (PNUE), as the indices of resource-use efficiency were studied in mustard (Brassica juncea L.) plants grown under limited water conditions with low-N (100 mg N kg−1 soil) and sufficient-N (200 mg N kg−1 soil) and sprayed with 0 or 0.5 mM salicylic acid (SA). Application of SA increased water potential, osmotic potential, WUE, and the incorporation of soil N into photosynthetic machinery by enhancing PNUE. It also increased photosynthesis of plants maximally by increasing stomatal conductance and intercellular CO2 concentration under water-deficit stress. This increase was greater in the presence of sufficient-N where 0.5 mM SA maximally enhanced the N metabolism, redox ratio that mitigated the oxidative stress. The application of SA on plants supplemented with N reduced ethylene and abscisic acid (ABA) synthesis. It could be inferred that SA enhanced N utilization through increase in NUE when it is sufficiently available, increasing the GSH content to maintain redox ratio and inhibit ABA-mediated stomatal closure to enhance the resource utilization and photosynthesis. SA also enhanced glucose utilization which prevented glucose-mediated photosynthetic repression under stress. Thus, SA application may impart a potential management tool for increasing photosynthetic NUE, WUE, and photosynthesis under drought

Ethylene signaling under stressful environments: analyzing collaborative knowledge

Ethylene is a gaseous plant growth hormone that regulates various plant developmental processes, ranging from seed germination to senescence. The mechanisms underlying ethylene biosynthesis and signaling involve multistep mechanisms representing different control levels to regulate its production and response. Ethylene is an established phytohormone that displays various signaling processes under environmental stress in plants. Such environmental stresses trigger ethylene biosynthesis/action, which influences the growth and development of plants and opens new windows for future crop improvement. This review summarizes the current understanding of how environmental stress influences plants’ ethylene biosynthesis, signaling, and response. The review focuses on (a) ethylene biosynthesis and signaling in plants, (b) the influence of environmental stress on ethylene biosynthesis, (c) regulation of ethylene signaling for stress acclimation, (d) potential mechanisms underlying the ethylene-mediated stress tolerance in plants, and (e) summarizing ethylene formation under stress and its mechanism of action

Montelukast jest skutecznym lekiem w zapobieganiu zespołowi hiperstymulacji jajników: badania eksperymentalne

Objectives: To determine the efficacy of montelukast in comparison with cabergoline in the prevention of ovarian hyperstimulation syndrome (OHSS) in rats. Material and methods: An experimental OHSS model was formed in 35 female Wistar rats. Rats (22 days old) were randomized into 5 groups, each containing 7 animals. The control group received no therapy; the mild OHSS group was administered pregnant mare serum gonadotropin (PMSG) 10 IU for 4 days, hCG 10 IU on the 5th day; the severe OHSS group received PMSG 10 IU for 4 days, hCG 30 IU on the 5th day. The montelukast group: received montelukast 10 mg/kg/day and the cabergoline group was administered cabergoline 100μg/kg/day via oral gavage for 6 days (days 22–27), in addition to those of severe OHSS. All groups were sacrificed on 28th day. Body weight, ovarian diameter and weight, vascular permeability, vascular endothelial growth factor (VEGF), semiquantitative VEGF receptor-1, and VEGF receptor-2 (VEGFR-2) immunohistochemistry were evaluated. Results: Ovarian diameter and VEGF expression were significantly lower in the montelukast and cabergoline groups than in the severe OHSS group. While montelukast was more effective in limiting vascular permeability in the severe OHSS, cabergoline was superior to montelukast with respect to the limiting effect on increased body weight and VEGFR-2 expression. Conclusions: The VEGF/VEGFR-2 interaction plays an important role in OHSS pathogenesis. Montelukast limits VEGF expression, and cabergoline reduces both VEGF and VEGFR-2 expressions; they are both effective therapies for the prevention of severe OHSS.Cel: Ocena skuteczności montelukastu w porównaniu z kabergoliną w zapobieganiu zespołowi hiperstymulacji jajników (OHSS) u szczurów. Materiał i metoda: Model doświadczalny OHSS stanowiło 35szczurów rasy Wistar, płci żeńskiej. Szczury (22 dniowe) podzielono na 5 grup, każda zawierająca 7 zwierząt. Grupa kontrolna nie otrzymała żadnej terapii. Grupa z łagodnym OHSS otrzymała gonadotropinę z surowicy ciężarnych klaczy (PMSG) w ilości 10IU przez 4 dni, hCG 10IU w 5 dniu, grupa z ciężkim OHSS otrzymała PMSG 10IU przez 4 dni, hCG 30IU w 5 dniu. Grupa z montelukastem otrzymała montelukast w dawce 10mg/kg/dzień a grupa z kabergoliną otrzymała kabergolinę 100μg/kg/dzień przez doustny zgłębnik przez 6 dni (dni 22-27). Wszystkie zwierzęta zabito w 28 dniu. Oceniono masę ciała, wymiar i wagę jajników, przepuszczalność naczyń, czynnik wzrostu śródbłonka naczyń (VEGF) oraz w immunohistochemii półilościowo receptor – 1 VEGF i receptor-2 VEGF. Wyniki: Wymiar jajnika oraz ekspresja VEGF były istotnie niższe w grupach z monelukastem i kabergoliną niż w grupie z ciężkim OHSS. Podczas gdy montelukast był bardziej skuteczny w ograniczaniu przepuszczalności śródbłonków w ciężkim OHSS, to kabergolina okazała się lepsza od montelukastu po uwzględnieniu ograniczającego efektu zwiększonej masy ciała i ekspresji VEGFR-2. Wnioski: Wzajemne oddziaływanie VEGF/VEGFR-2 odgrywa istotną role w patogenezie OHSS. Montelukast ogranicza ekspresję VEGF, a kabergolina zmniejsza zarówno ekspresję VEGF jak i VEGFR-2; obie terapie są skuteczne w zapobieganiu ciężkiemu OHSS