bims-polyam 2020-03-15 papers

Issue of 2020‒03‒15
four papers selected by
Alexander Ivanov
Engelhardt Institute of Molecular Biology

Biomolecules. 2020 Mar 06. pii: E406. [Epub ahead of print]10(3):

Hydroxylamine Analogue of Agmatine: Magic Bullet for Arginine Decarboxylase.

Mervi T Hyvönen, Tuomo A Keinänen, Gulgina K Nuraeva, Dmitry V Yanvarev, Maxim Khomutov, Elena N Khurs, Sergey N Kochetkov, Jouko Vepsäläinen, Alexander A Zhgun, Alex R Khomutov.

The biogenic polyamines, spermine, spermidine (Spd) and putrescine (Put) are present at micro-millimolar concentrations in eukaryotic and prokaryotic cells (many prokaryotes have no spermine), participating in the regulation of cellular proliferation and differentiation. In mammalian cells Put is formed exclusively from L-ornithine by ornithine decarboxylase (ODC) and many potent ODC inhibitors are known. In bacteria, plants, and fungi Put is synthesized also from agmatine, which is formed from L-arginine by arginine decarboxylase (ADC). Here we demonstrate that the isosteric hydroxylamine analogue of agmatine (AO-Agm) is a new and very potent (IC50 3•10-8 M) inhibitor of E. coli ADC. It was almost two orders of magnitude less potent towards E. coli ODC. AO-Agm decreased polyamine pools and inhibited the growth of DU145 prostate cancer cells only at high concentration (1 mM). Growth inhibitory analysis of the Acremonium chrysogenum demonstrated that the wild type (WT) strain synthesized Put only from L-ornithine, while the cephalosporin C high-yielding strain, in which the polyamine pool is increased, could use both ODC and ADC to produce Put. Thus, AO-Agm is an important addition to the set of existing inhibitors of the enzymes of polyamine biosynthesis, and an important instrument for investigating polyamine biochemistry.

Keywords: Acremonium chrysogenum; Escherichia coli; O-substituted hydroxylamine; Polyamines; arginine decarboxylase; nanomolar inhibitor; ornithine decarboxylase

DOI: https://doi.org/10.3390/biom10030406

Langmuir. 2020 Mar 11.

Femtomolar Detection of Spermidine using Au Decorated SiO2 Nanohybrid on Plasmon-Coupled Extended Cavity Nanointerface: A Smartphone based Fluorescence Dequenching approach.

Seemesh Bhaskar, N Charan S S Kowshik, S Prathap Chandran, Sai Sathish Ramamurthy.

Coupling of photons with molecular emitters in different nanocavities have resulted in transformative plasmonic applications. The rapidly expanding field of surface plasmon-coupled emission (SPCE) has synergistically employed subwavelength optical properties of localized surface plasmon resonance (LSPR) supported by nanoparticles (NPs) and propagating surface plasmon polaritons assisted by metal thin films for diagnostic and point-of-care analysis. Gold nanoparticles (AuNPs) significantly quench the molecular emission from fluorescent molecules (at close distances < 5 nm). More often, complex strategies are employed for providing a spacer layer around the AuNPs to avoid direct contact with fluorescent molecules, thereby preventing quenching. In this study we demonstrate a rapid and facile strategy with the use of Au-decorated SiO2 NPs (AuSil), a metal (Au)-dielectric (SiO2) hybrid material for dequenching the otherwise quenched fluorescence emission from radiating dipoles and to realize 88-fold enhancement using the SPCE platform. Different loading of AuNPs were studied to tailor fluorescence emission enhancements in spacer, cavity and extended (ext.) cavity nanointerfaces. We also present femtomolar detection of spermidine using this nanohybrid in a highly desirable ext. cavity interface. This interface serves as an efficient coupling configuration with dual benefits of spacer and cavity architectures that has been widely explored hitherto. The multifold hot-spots rendered by the AuSil nanohybrids assist in augmented electromagnetic (EM)-field intensity that can be captured using a smartphone based SPCE platform presenting excellent reliability and reproducibility in spermidine detection.

DOI: https://doi.org/10.1021/acs.langmuir.9b03869

J Food Biochem. 2020 Mar 10. e13167

Digestive abilities, amino acid transporter expression, and metabolism in the intestines of piglets fed with spermine.

Guangmang Liu, Weiwei Mo, Wei Cao, Gang Jia, Hua Zhao, Xiaoling Chen, Caimei Wu, Ruinan Zhang, Jing Wang.

This study evaluated the effects of spermine supplementation on the digestion, transport, and metabolism of nutrients in the jejuna of piglets. Of the 80 piglets examined, 40 received 0.4 mmol/kg body weight spermine, and the other half were randomly distributed such that the restricted nutrient intake supplemented with the saline solution for 7 hr and 3, 6, or 9 days in pairs. Spermine supplementation increased the lipase and trypsin activities (p < .05), and spermine increased the mRNA levels of maltase, sucrase, and aminopeptidase N (APN) but decreased the lactase gene expression (p < .05). Moreover, spermine increased the mRNA expression levels of amino acid transporters (p < .05). Spermine increased the jejunum glycerolphosphocholine, lipid, and taurine levels and decreased the choline and amino acids levels (p < .05). In summary, spermine can promote the digestion, transport, and metabolism of nutrients in piglets. PRACTICAL APPLICATIONS: Meat, fish, dairy products, and fruits contain polyamines (i.e., spermine, spermidine, and putrescine). Spermine plays an important role in the cell proliferation, growth, and differentiation, and spermine supplementation can improve the growth of broilers, growth performance of early weaning piglets, and intestinal maturation. The results of this study suggest that spermine can improve the digestion, transport, and metabolism of nutrients in piglets.

Keywords: amino acid transporters; digestive abilities; intestine; piglets; spermine

DOI: https://doi.org/10.1111/jfbc.13167

Physiol Mol Biol Plants. 2020 Feb;26(2): 233-245

Exogenous application of spermine and putrescine mitigate adversities of drought stress in wheat by protecting membranes and chloroplast ultra-structure.

Nemat Hassan, Heba Ebeed, Alshafei Aljaarany.

Polyamines (PAs) are positively charged molecules known to mitigate drought stress; however, little is known about their mechanism of alleviating drought stress. We investigated the effects of PAs exogenously applied as a seed primer and as a foliar spray on the growth, membrane stability (MS), electrolyte leakage (EL), Na+ and K+ cations, reactive oxygen species (ROS), catalase (CAT; EC 1.11.1.6) and guaiacol peroxidase (GPX; EC 1.11.1.7) activity and chloroplast ultra-structure in wheat (Triticum aestivum L.; cv. Sakha-94) under drought stress. Three PA solutions, namely, putrescine, spermine and a mixture of the two (Mix), were each applied at a concentration of 100 µM. Our study demonstrated that the retardation of chlorophyll loss and elevation of Rubisco levels were involved in PA-enhanced growth under drought stress. These relationships were mainly reflected in elevated fresh weight and dry weight in response to foliar spraying with all PA solutions and seed priming with the Mix solution. The elevated growth seemed to be due to increased photosynthetic pigments, protein and Rubisco. In contrast, drought decreased growth, photosynthetic pigments, protein and Rubisco. MS was enhanced by PAs applied as a seed primer or foliar spray, as shown by clear reductions in EL %, malondialdehyde (MDA) content and the Na+/K+ ratio as well as reduced ROS markers and elevated CAT (but not GPX) activity. Further study showed that the Mix solution of PAs, applied either during seed priming or as a foliar spray, improved chloroplast ultra-structure, suggesting that improvements in Rubisco and photosynthetic pigments were involved in PA maintenance of chloroplast stability. Therefore, the present study showed that elevated CAT activity is the main mechanism through which PAs reduce ROS and MDA, thereby improving MS and protecting mesophyll cells structurally and functionally under drought stress in wheat.

Keywords: Chloroplast; Drought; Membrane injury; Oxidative damage; Polyamines; Wheat

DOI: https://doi.org/10.1007/s12298-019-00744-7