bims-polyam 2020-01-05 papers

J Chromatogr B Analyt Technol Biomed Life Sci. 2019 Dec 15. pii: S1570-0232(19)31435-7. [Epub ahead of print]1137 121936

Simultaneous determination of eight arginine-related metabolites in cellular extracts using liquid chromatography-tandem mass spectrometry.

Sarmila Amatya, Yumi Shin, Jeong Yeop Ha, Su-Jun Lee, Sang Wook Kang, Byungsuk Kwon, Dong Hyun Kim.

A simple, sensitive, and rapid liquid chromatography (LC)-tandem mass spectrometry (MS/MS) method was developed for the simultaneous determination of arginine and its pathway-related metabolites (ornithine, proline, citrulline, glutamate, agmatine, spermidine, and spermine) in cellular extracts. Cells were lysed and cellular proteins precipitated by the addition of acetonitrile followed by ultra-sonication. Supernatants were analyzed using a Chromolith High Resolution RP-18 endcapped column (100 × 4.6 mm, 1.15 μm, 150 Å), with mobile phases of 0.1% formic acid solution and 0.1% formic acid in acetonitrile. Detection was carried out in multiple reaction monitoring (MRM) mode. Calibration curves showed linearity (r2 > 0.99) for all metabolites over the calibration ranges used. The intra- and inter-day precision was less than 13.5%, and the accuracy was between 91.3 and 114.7%. The method developed in this study was successfully applied to measure arginine and its pathway-related metabolites, which are related to nitric oxide synthase/arginase pathways in mouse bone marrow-derived dendritic cells (BMDCs). The ability to simultaneously measure arginine and its pathway-related metabolites is valuable for better understanding local and systemic inflammatory processes.

Keywords: Analysis; Arginine and its metabolites; Bone marrow-derived dendritic cells; Liquid chromatography (LC)–tandem mass spectrometry (MS/MS)

DOI: https://doi.org/10.1016/j.jchromb.2019.121936

Mol Plant. 2019 Dec 28. pii: S1674-2052(19)30407-1. [Epub ahead of print]

Identification of naturally-occurring polyamines as nematode Meloidogyne incognita attractants.

Morihiro Oota, Allen Yi-Lun Tsai, Dan Aoki, Yasuyuki Matsushita, Syuuto Toyoda, Kazuhiko Fukushima, Kentaro Saeki, Kei Toda, Laetitia Perfus-Barbeoch, Bruno Favery, Hayato Ishikawa, Shinichiro Sawa.

Root-knot nematodes (RKN, genus Meloidogyne) are a class of plant parasites that seek out and infect roots of many plant species. It is believed that RKN target certain signaling molecules derived from plants to locate their hosts, however currently no plant compound has been unambiguously identified as a universal RKN attractant. To address this question, we screened a chemical library of synthetic compound for M. incognita attractants. Break-down product of aminopropylamino-anthraquinone, 1,3-diaminopropane, as well as related compounds putrescine and cadaverine were found to attract M. incognita. After examining various polyamines, M. incognita were found to be attracted specifically by natural compounds that possess three to five methylene groups between two terminal amino groups. Using cryo-TOF-SIMS/SEM, cadaverine was indeed detected in soybean root cortex cells and the surrounding rhizosphere, establishing a chemical gradient. In addition to cadaverine, putrescine and 1,3-diaminopropane were also detected in root exudate by HPLC-MS/MS. Furthermore, exogenously applied cadaverine is sufficient to enhance M. incognita infection of Arabidopsis seedlings. These results suggest M. incognita may indeed target polyamines to locate the appropriate host plants, and these naturally-occurring polyamines may have viable applications in agriculture to develop protection strategies for crops from RKN infections.

DOI: https://doi.org/10.1016/j.molp.2019.12.010

Genomics. 2019 Dec 26. pii: S0888-7543(19)30673-1. [Epub ahead of print]

Molecular characterization and ornithine-urea cycle genes expression in air-breathing magur catfish (Clarias magur) during exposure to high external ammonia.

Bodhisattwa Banerjee, Debaprasad Koner, Rubaiya Hasan, Nirmalendu Saha.

The air-breathing magur catfish (Clarias magur) is a potential ureogenic teleost because of its functional ornithine-urea cycle (OUC), unlike typical freshwater teleosts. The ability to convert ammonia waste to urea was a significant step towards land-based life forms from aquatic predecessors. Here we investigated the molecular characterization of some OUC genes and the molecular basis of stimulation of ureogenesis via the OUC in magur catfish. The deduced amino acid sequences from the complete cDNA coding sequences of ornithine transcarbamyolase, argininosuccinate synthase, and argininosuccinate lyase indicated that phylogenetically magur catfish is very close to other ureogenic catfishes. Ammonia exposure led to a significant induction of major OUC genes and the gene products in hepatic and in certain non-hepatic tissues of magur catfish. Hence, it is reasonable to assume that the induction of ureogenesis in magur catfish under hyper-ammonia stress is mediated through the activation of OUC genes as an adaptational strategy.

Keywords: Gene induction; Hyper-ammonia stress; Molecular phylogenetics; Protein expression; Sequence analysis; Ureogenesis

DOI: https://doi.org/10.1016/j.ygeno.2019.12.021

Sci Rep. 2019 Dec 31. 9(1): 20409

Nafamostat and sepimostat identified as novel neuroprotective agents via NR2B N-methyl-D-aspartate receptor antagonism using a rat retinal excitotoxicity model.

Masahiro Fuwa, Masaaki Kageyama, Koji Ohashi, Masaaki Sasaoka, Ryuichi Sato, Masami Tanaka, Kei Tashiro.

In addition to its role in the treatment of pancreatitis, the serine protease inhibitor nafamostat exhibits a retinal protective effect. However, the exact mechanisms underlying this effect are unknown. In this study, the neuroprotective effects of nafamostat and its orally active derivative sepimostat against excitotoxicity were further characterised in vitro and in vivo. In primary rat cortical neurons, nafamostat completely suppressed N-methyl-D-aspartate (NMDA)-induced cell death. Intravitreal injection of nafamostat and sepimostat protected the rat retina against NMDA-induced degeneration, whereas the structurally related compounds, gabexate and camostat, did not. The neuroprotective effects of nafamostat and the NR2B antagonist ifenprodil were remarkably suppressed by spermidine, a naturally occurring polyamine that modulates the NR2B subunit. Both nafamostat and sepimostat inhibited [3H]ifenprodil binding to fractionated rat brain membranes. Thus, nafamostat and sepimostat may exert neuroprotective effects against excitotoxic retinal degeneration through NMDA receptor antagonism at the ifenprodil-binding site of the NR2B subunit.

DOI: https://doi.org/10.1038/s41598-019-56905-x

BMC Genomics. 2019 Dec 30. 20(1): 1034

Hydrogen cyanamide induces grape bud endodormancy release through carbohydrate metabolism and plant hormone signaling.

Dong Liang, Xiaojing Huang, Yanqiu Shen, Tian Shen, Huifen Zhang, Lijin Lin, Jin Wang, Qunxian Deng, Xiulan Lyu, Hui Xia.

BACKGROUND: Grape buds exhibit non-uniform, or delayed, break in early spring in subtropical regions because the accumulation of chilling is insufficient. Hydrogen cyanamide (H2CN2, HC) can partially replace chilling to effectively promote bud sprouting and is used widely in warm winter areas. However, the exact underlying mechanism of grape bud release from endodormancy induced by HC remains elusive.
RESULTS: In this study, the transcriptome of grape winter buds under in vitro conditions following HC and water treatment (control) was analyzed using RNA-seq technology. A total of 6772 differentially expressed genes (DEGs) were identified. Furthermore, the gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analysis revealed that starch and sucrose metabolism and plant hormone signaling transduction were most enriched out of the 50 total pathways. HC treatment induced the upregulated expression of sucrose synthase (SUS), sucrose phosphate synthase (SPS), α-amylase (AM), and β-amylase (BM) and downregulated expression of sucrose invertase (INV), hexokinase (HK), fructokinase (FK), soluble starch synthase (SS), and granule-bound starch synthase (GBSS). Hence, the starch concentration in the HC-treated group was significantly lower than that in control, whereas soluble sugar content in the HC-treated group increased quickly and was higher than that in control between 0 and 8 d. The concentration of indoleacetic acid (IAA) and zeatin (ZT) increased, whereas that of abscisic acid (ABA) and gibberellin (GA) decreased in HC treated group, which coincided with the expression level of genes involved in above hormone signals. The content of hydrogen peroxide (H2O2) and enzyme activity of superoxide dismutase (SOD) and peroxidase (POD) were increased in grape buds with HC treatment, whereas catalase (CAT) activity was decreased. HC treatment increased the expression of POD, SOD, primary amine oxidase (PAO), polyamine oxidase (PAOX), and glutathione peroxidase (GSH-Px).
CONCLUSION: Based on these results, it is possible to propose a mechanistic model that underlies the regulation of endodormancy release in grapevine buds by exogenous HC application.

Keywords: Carbohydrate; Endodormancy release; Grape; Hydrogen cyanamide; Plant hormone

DOI: https://doi.org/10.1186/s12864-019-6368-8

J Biosci. 2019 Dec;pii: 136. [Epub ahead of print]44(6):

Involvement of putrescine in osmotic stress-induced ABA signaling in leaves of wheat seedlings.

H Y DU, G S Chen, J M Yu, Y Y Bao, G T Liu, H P Liu, R Gupta.

To elucidate one mechanism by which putrescine (Put) functions in plant signaling under osmotic stress, Put and ABA contents, and plasma membrane-NADPH oxidase (PM-NOX) activity were detected in wheat seedling leaves. Under osmotic stress, ABA and Put contents, PM-NOX activity, and PM-NOX-dependent O2.- production all increased. The inhibitor tungstate (T) of ABA bio-synthesis reduced the increases in ABA and Put contents under osmotic stress. The inhibitor D-arginine (D-Arg) of Put bio-synthesis didn't reduce osmotic-induced increase of ABA, but it inhibited the increases of PM-NOX activity and O2 . - production, and the inhibitory effects were reversed by exogenous Put. These findings suggested that ABA might regulate Put biosynthesis, and Put might regulate PM-NOX activity. Treatments with three inhibitors imidazole (I), diphenylene iodonium (DPI) and pyridine (P) of PM-NOX reduced significantly not only O2 . - production, but also the stress-induced increase of Put content, which indicated that O2 . - production might regulate Put biosynthesis. Treatments with EGTA (Ca2+ chelator), La3+ and verapamil (V) (Ca2+ channel blockers) reduced significantly the stress-induced increase of Put content, which suggested that Ca2+ might regulate Put biosynthesis. With these findings, it could be concluded that Put was involved in ABA signaling induced by osmotic stress via regulating PM-NOX activity in wheat seedling leaves.