scholarly journals AGO-unbound cytosolic pool of mature miRNAs in plant cells reveals a novel regulatory step at AGO1 loading

2019 ◽  
Vol 47 (18) ◽  
pp. 9803-9817 ◽  
Author(s):  
Ágnes Dalmadi ◽  
Péter Gyula ◽  
Jeannette Bálint ◽  
György Szittya ◽  
Zoltán Havelda
Keyword(s):  
Molecular Weight ◽  
High Throughput Sequencing ◽  
Size Range ◽  
Plant Cells ◽  
Molecular Size ◽  
Mature Mirnas ◽  
Biologically Active ◽  
Limiting Factor ◽  
Low Molecular Weight ◽  
Large Set

Abstract RNA interference (RNAi) is mediated by small, 20-24-nt-long, non-coding regulatory (s)RNAs such as micro (mi) and small interfering (si) RNAs via the action of ARGONAUTE (AGO) proteins. High-throughput sequencing of size-separated sRNA pools of plant crude extracts revealed that the majority of the canonical miRNAs were associated with high molecular weight RNA-induced silencing complexes co-migrating with AGO1 (HMW RISC). In contrast, the majority of 24-nt-long siRNAs were found in association with low molecular weight complexes co-migrating with AGO4 (LMW RISC). Intriguingly, we identified a large set of cytoplasmic sRNAs, including mature miRNA sequences, in the low molecular size range corresponding to protein-unbound sRNAs. By comparing the RISC-loaded and protein-unbound pools of miRNAs, we identified miRNAs with highly different loading efficiencies. Expression of selected miRNAs in transient and transgenic systems validated their altered loading abilities implying that this process is controlled by information associated with the diverse miRNA precursors. We also showed that the availability of AGO proteins is a limiting factor determining the loading efficiency of miRNAs. Our data reveal the existence of a regulatory checkpoint determining the RISC-loading efficiencies of various miRNAs by sorting only a subset of the produced miRNAs into the biologically active RISCs.

Characterisation of Persistent Anti-Xa Activity Following Administration of the Low Molecular Weight Heparin Enoxaparin Sodium (Clexane)

1994 ◽  
Vol 72 (02) ◽  
pp. 275-280 ◽  
Author(s):  
David Brieger ◽  
Joan Dawes
Keyword(s):  
Molecular Weight ◽  
Enoxaparin Sodium ◽  
Antithrombin Iii ◽  
Anticoagulant Activity ◽  
Active Material ◽  
Biologically Active ◽  
Size Exclusion ◽  
Low Molecular Weight ◽  
Exclusion Chromatography ◽  
Liver And Kidney

SummaryIt is widely reported that persistent anti-Xa activity follows administration of low molecular weight heparins. To identify the effectors of this activity we have injected 125I-labelled Enoxaparin sodium into rabbits and subsequently analysed the circulating radiolabelled material and anti-Xa activity by affinity and size exclusion chromatography. Antithrombin III-binding material derived from the injected drug was responsible for all the anti-Xa amidolytic activity. At early times after injection additional anticoagulant activity which was largely attributable to tissue factor pathway inhibitor was measured by the Heptest clotting assay after removal of glycosaminoglycans from plasma samples. Small radiolabelled fragments, including penta/hexasaccharide with affinity for antithrombin III, were detectable in the circulation 1 week later, and sulphated oligosaccharides persisted for 3-4 weeks. Significant quantities of radiolabel remained in the liver and kidney several weeks post-injection; these organs may sequester some of the injected drug and give rise to circulating biologically active material by degradation and secretion of catabolic products into the plasma.

Localization of heparin and low-molecular-weight heparin in the rat kidney

2004 ◽  
Vol 91 (05) ◽  
pp. 927-934 ◽  
Author(s):  
Vivian Douros ◽  
Thomas Podor ◽  
Stephen Shaughnessy ◽  
Jeffrey Weitz ◽  
Edward Young
Keyword(s):  
Molecular Weight ◽  
Low Molecular Weight Heparin ◽  
Rat Kidney ◽  
Organic Anion ◽  
Molecular Size ◽  
Immunohistochemical Analysis ◽  
Immunoperoxidase Staining ◽  
Low Molecular Weight ◽  
Renal Tubular Cells ◽  
Renal Tubular

SummaryUnfractionated heparin (UFH) and low-molecular-weight heparin (LMWH) are cleared, at least in part, by the kidneys through a poorly understood process. This study was undertaken to explore the mechanism of renal clearance of these drugs. Rats were given fluorescein-5-isothiocyanate (FITC)-labeled UFH or LMWH intravenously. At intervals after injection, rats were euthanized and the kidneys were harvested and subjected to immunohistochemical analysis and fluorescence microscopy. Both UFH and LMWH were localized to renal tubular cells and no immunoperoxidase staining or fluorescence was detected in glomeruli. Autoradiography demonstrated similar intracellular distribution of radio-labeled UFH suggesting that this phenomenon is independent of the method used to label heparin. Fluoresence in the tubules increased as a function of time after UFH injection, but reached a plateau after LMWH injection suggesting that the rate of renal tubular uptake depends on the molecular size of the heparin. When administered prior to FITC-labeled UFH or LMWH, probenecid, a renal organic anion inhibitor, decreased the renal tubular uptake of the heparins, whereas cimetidine, a renal organic cation inhibitor, had no effect. These findings suggest that renal excretion of UFH and LMWH primarily reflects tubular uptake via an organic anion transport mechanism.

scholarly journals Biologically active ion exchange (BIEX) for NOM removal and membrane fouling prevention

2017 ◽  
Vol 17 (4) ◽  
pp. 1178-1184 ◽  
Author(s):  
M. Schulz ◽  
J. Winter ◽  
H. Wray ◽  
B. Barbeau ◽  
P. Bérubé
Keyword(s):  
Molecular Weight ◽  
Biological Activity ◽  
Ion Exchange ◽  
Membrane Fouling ◽  
Building Blocks ◽  
Biologically Active ◽  
Low Molecular Weight ◽  
Effective Removal ◽  
Pre Treatment ◽  
The Impact

The natural organic matter (NOM) removal efficiency and regeneration behavior of ion-exchange filters with promoted biological activity (BIEX) was compared to operation where biological activity was suppressed (i.e. abiotic conditions). The impact of BIEX pre-treatment on fouling in subsequent ultrafiltration was also investigated. Biological operation enhanced NOM removal by approximately 50% due to an additional degradation of smaller humic substances, building blocks and low molecular weight acids. Promotion of biological activity significantly increased the time to breakthrough of the filters and, therefore, is expected to lower the regeneration frequency as well as the amount of regenerate of which to dispose. Pre-treatment using BIEX filters resulted in a significant decrease in total and irreversible fouling during subsequent ultrafiltration. The decrease was attributed to the effective removal of medium and low molecular weight NOM fractions. The results indicate that BIEX filtration is a robust, affordable and easy-to-operate pre-treatment approach to minimize fouling in ultrafiltration systems and enhance the quality of the produced permeate.

scholarly journals BCG, muramylpeptides, trained immunity (part II): a low molecular weight alternative to multicomponent bacterial immunostimulants for prevention of respiratory infections during a pandemic

2021 ◽  
Vol 93 (1) ◽  
pp. 108-113
Author(s):  
Oleg V. Kalyuzhin ◽  
Tatiana M. Andronova ◽  
Alexander V. Karaulov
Keyword(s):  
Molecular Weight ◽  
Respiratory Infections ◽  
Biologically Active ◽  
Low Molecular Weight ◽  
Trained Immunity ◽  
Nonspecific Effects ◽  
Dosing Regimens ◽  
Glycolipid Fraction ◽  
Bacterial Lysates

During a pandemic, nonspecific immunoprophylaxis of SARS-CoV-2 infection and other acute respiratory infections (ARI), which can worsen the course of COVID-19, is increasingly in demand in addition to specific immunization. BCG vaccine appears to be one of the candidate immunostimulants in this regard. At the same time, other microbe-derived preparations capable of inducing a state of trained immunity deserve attention. BCG and other bacterial immunostimulatory agents containing a large number of biologically active subunits have long been considered as objects of search for promising pharmacological substances. The review analyzes the linkages between BCG, mycobacterial adjuvants, bacterial lysates, trained immunity, muramylpeptides (MPs) and NOD2 receptors in light of the choice of a low molecular weight alternative to multicomponent bacterial immunostimulants for ARI prevention during the COVID-19 pandemic. The search for key molecules by which bacteria stimulate innate and adaptive immune responses proceeds in a spiral. On different loops of this spiral, MPs have repeatedly reproduced the nonspecific effects of multicomponent bacterial adjuvants, vaccines and immunostimulants. MPs and peptidoglycans containing MPs determine the adjuvant properties of the cell walls of mycobacteria and their peptide-glycolipid fraction (wax D). MPs were able to replace Mycobacterium tuberculosis in complete Freunds adjuvant. MPs determine the NOD2-dependent ability of BCG to induce trained immunity. Probably, MPs provide NOD2-mediated long-term prophylactic action of bacterial lysates. All of the above has prompted revisiting the previously obtained evidence of the efficacy of glucosaminylmuramyl dipeptide (GMDP) as a NOD2 agonist in treatment/prevention of respiratory infections. We speculate here that MPs, in particular GMDP, at rational dosing regimens will be able to reproduce many aspects of the nonspecific effects of BCG and multicomponent bacterial immunostimulants in preventing ARI during the COVID-19 pandemic and in the post-pandemic period.

scholarly journals Comparative study of technologies for extraction of biologically active substances from the raw material of animal origin

2021 ◽  
Vol 6 (3) ◽  
pp. 226-235
Author(s):  
E. R. Vasilevskaya ◽  
M. A. Aryuzina ◽  
E. S. Vetrova
Keyword(s):  
Molecular Weight ◽  
Trichloroacetic Acid ◽  
Biologically Active Substances ◽  
Biologically Active ◽  
Animal Origin ◽  
Low Molecular Weight ◽  
Acid Extraction ◽  
Trichloroacetic Acid Solution ◽  
Wide Range ◽  
Active Substances

Technologies of isolation and concentration of biologically active substances, developed in the middle of the 20th century, need adjustment and adaptation to modern conditions both to increase the activity of substances and for greater economic efficiency. The aim of the research is the comparison of dynamics of biologically active compounds extraction from porcines pancreas in two methods: the saline method based on 0.9% sodium chloride solution, and the acidic method based on 2.4% trichloroacetic acid solution. Also the purpose of research is to assess the possibilities for further optimization of technologies. The total protein concentration based on the biuret reaction in the samples taken during the extraction, as well as the calculation and analysis of the point degrees and rates of extraction are chosen as the controlled parameters. Local maxima of the protein yields into the extractant media at the 60th, 135th and 255th minute were recorded during saline extraction; and at the 75th and 135th minute during acid extraction. Also the proteomic profile of the extracts was studied. Wide range of compounds with molecular weight of less than 52 kDa was found in extracts based on physiological saline solution, and protein substances of whole presented range of molecular weights in trichloroacetic acid based extracts were considered. The predominance of low molecular weight protein fraction of interest was noted also in this method of extraction in comparison with the other methods of extraction. According to the UniProt database, we assume availability of probable compounds with a molecular weight of less than 30 kDa in the purified acidic extract. The presence of some proteins absent in the final saline extract was noted. The acidic erythrograms showed a weak degrading effect of both types of extracts on the membranes of rat erythrocytes, as well as the cytoprotective effect of acidic ultrafiltrates (less than 3 kDa). The obtained results prove a better efficiency of trichloroacetic acid extraction method used for obtaining a mixture of a wide range of compounds, including biologically active substances of low molecular weight.

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