Corrigendum to: Ammonium metabolism in Selaginella bryopteris in response to dehydration-rehydration and characterisation of desiccation tolerant, thermostable, cytosolic glutamine synthetase from plant

Water deficit (WD) has adverse effects on plant growth, and acclimation requires responses allowing primary metabolism to continue. Resurrection plants can serve as model system to gain insight into metabolic regulation during WD. We herein report the response of a resurrection lycophyte, Selaginella bryopteris, to dehydration-rehydration cycle with emphasis on ammonium metabolism. Dehydration of S. bryopteris fronds resulted in decrease of total protein and increase of free ammonium levels and the effect was reversed on rehydration. The proline content increased twice after 24 h of dehydration, which again recovered to background levels comparable to that at full turgor state. The specific activity of glutamine synthetase (GS) didn’t change significantly till 6 h and then declined by 21% after 24 h of dehydration, whereas specific activities of glutamate synthase (GOGAT) and aminating glutamate dehydrogenase (GDH) were enhanced significantly during dehydration. The deaminating activity of GDH also increased during dehydration albeit at a slower rate. Immunoblot analysis indicated overexpression of GS and GDH polypeptides during dehydration and their levels declined on rehydration. The results suggested significant role of GDH along with GS/GOGAT in production of nitrogen-rich amino acids for desiccation tolerance. Unlike higher plants S. bryopteris expressed GS only in cytosol. The enzyme had pH and temperature optima of 5.5 and 60°C, respectively, and it retained 96% activity on preincubation at 60°C for 30 min indicating thermostability. Hence, like higher plants the cytosolic GS from S. bryopteris has a conserved role in stress tolerance.

Utilization of Different Probiotics on Growth and Survival Rate of Blacktail Zebra fish (Dascyllus melanurus)

Blacktail Zebra fish (Dascyllus melanurus) is more caught the sea by fishermen. There are several limitations which are lower growth and feet effisincy trought the natural habitat. Hence, an optimal feed combination is consideret to be provided during fish rearing to increase their growth. One of ideas was to use probiotic, which is bacteria that are able to decompose organic materials to change toxic compounds is valauable matter to the environment. For instance, ammonia and nitrite can be converted into free ammonium. The additional in an artificial feed is exfected to gain aquaculture activities. The study was conducted for 56 days from August to October 2019 in Wetlab Kastela FPK of Khairun University. Experiment and four treatments were applied using Filling Randomized Design (RAL). The result shows that different additional probiotic effected the growth and survival rate of Blacktail zebra fish. The highest was found in probio7 15 ml/kg feed, which gave 0,88g of total growth’; and the lowest was 0,27g which was found in the treatment A ((control)/ Water quality was checked weekly and in normal condition for the growth of the growth of blacktail zebra fish.

Carbon and nitrogen metabolism in young Tachigali vulgaris plants subjected to water deficit

Plants’ biochemical responses to water deficit are associated with their ability to synthesize accumulate osmolytes compatible to regulatory properties of water potential. The aim of the current study is to evaluate carbon and nitrogen metabolism in Tachigali vulgaris plants subjected to three water suspension periods. The experiment was carried out in greenhouse and followed a completely randomized design, at 3 x 2 factorial arrangement (three times: zero, five and ten water suspension days; and two water conditions: control and water deficit), with 4 repetitions; results were subjected to analysis of variance and means were compared through t-test at 5% probability level, in statistical package (Assistat 7.7 beta). The following variables recorded decreased values: relative water content RWC in leaf tissue (by 32.14%); nitrate ion in leaves (by 18.67%) and in roots (by 14.40%); nitrate reductase enzyme activity in leaves (by 17.06%) and roots (by 15.77%); starch concentration in leaf tissue (by 44.98%) and roots (by 21.07%). On the other hand, the following variables recorded increased values: free ammonium concentration in leaves (by 64.83%) and roots (by 1.61%); total soluble amino acids in leaf tissue (by 28.03%) and roots (by 8.42%); total soluble carbohydrates in leaves (by 3.12%) and roots (by 11.05%); sucrose in leaves (by 4.77%) and roots (by 24.77%); proline in leaves (by 193.58%) and roots (by 57.26%). Biochemical processes observed in T. vulgaris plants were affected by water deficit, which indicated that this species is capable of adopting mechanisms and strategies in order to survive under stressful conditions.

Endogenous ABA alleviates rice ammonium toxicity by reducing ROS and free ammonium via regulation of the SAPK9–bZIP20 pathway

Ammonium (NH4+) is one of the principal nitrogen (N) sources in soils, but is typically toxic already at intermediate concentrations. The phytohormone abscisic acid (ABA) plays a pivotal role in responses to environmental stresses. However, the role of ABA under high-NH4+ stress in rice (Oryza sativa L.) is only marginally understood. Here, we report that elevated NH4+ can significantly accelerate tissue ABA accumulation. Mutants with high (Osaba8ox) and low levels of ABA (Osphs3-1) exhibit elevated tolerance or sensitivity to high-NH4+ stress, respectively. Furthermore, ABA can decrease NH4+-induced oxidative damage and tissue NH4+ accumulation by enhancing antioxidant and glutamine synthetase (GS)/glutamate synthetasae (GOGAT) enzyme activities. Using RNA sequencing and quantitative real-time PCR approaches, we ascertain that two genes, OsSAPK9 and OsbZIP20, are induced both by high NH4+ and by ABA. Our data indicate that OsSAPK9 interacts with OsbZIP20, and can phosphorylate OsbZIP20 and activate its function. When OsSAPK9 or OsbZIP20 are knocked out in rice, ABA-mediated antioxidant and GS/GOGAT activity enhancement under high-NH4+ stress disappear, and the two mutants are more sensitive to high-NH4+ stress compared with their wild types. Taken together, our results suggest that ABA plays a positive role in regulating the OsSAPK9–OsbZIP20 pathway in rice to increase tolerance to high-NH4+ stress.

Catalyst-Free [2,3]-Sigmatropic Rearrangement Reactions of Photochemically Generated Ammonium Ylides

The rearrangement reaction of ammonium ylides furnishes valuable α,α-disubstituted amino esters. In this work, we describe the visible-light photolysis reaction of aryldiazoacetates in the presence of tertiary amines that react via a free ammonium ylide in a sigmatropic rearrangement reaction to provide amino esters in moderate to very good yields (33 examples, up to 97% yield).