Your browser doesn't support javascript.
loading
Show: 20 | 50 | 100
Results 1 - 16 de 16
Filter
Add more filters










Publication year range
1.
Heliyon ; 10(10): e31013, 2024 May 30.
Article in English | MEDLINE | ID: mdl-38799754

ABSTRACT

Background: Manual traction, a therapeutic technique frequently employed in healthcare, involves applying controlled pulling force by hand, usually to the spine, to stretch muscles and decompress joints, thereby alleviating pain. This method can be particularly beneficial for addressing lumbosacral spine pain exacerbated by radicular symptoms, characterized by pain radiating from the lower back due to compression or irritation of spinal nerves. Purpose: This study aimed to compare the effects of manual traction against control group in alleviating the lumbosacral spine pain caused by radicular symptoms. Methods: A randomized controlled study design was utilized with a sample of 60 patients experiencing lumbosacral spine pain, evenly distributed between an experimental group (n = 30; receiving manual traction) and a control group (n = 30). Patients underwent assessments before and after six treatment sessions, which included the Straight Leg Raise test, modified Bragard's test, Kernig's test, and the visual analogue scale for pain perception. Results: Between-group significant differences were found at post-intervention, favoring the experimental group on SLR - Left (°) (p = 0.004; medium effect size), SLR - Right (°) (p = 0.004; medium effect size), Modified Bragard test - Left (°) (p = 0.024; small effect size), Modified Bragard test - Right (°) (p = 0.003; medium effect size), Kernig's Test - Left (°) (p = 0.013; medium effect size) and Kernig's Test - Right (°) (p = 0.010; medium effect size). Additionally, between-group significant differences were found at post-intervention, favoring the experimental group on VAS scores at SLR left (p < 0.001; medium effect size), and right (p < 0.001); medium effect size, Modified Bragard test left (p < 0.001; medium effect size) and right (p < 0.001; medium effect size) and at Kernig's Test left (p < 0.001; medium effect size) and right (p < 0.001; medium effect size). Conclusions: In conclusion, manual traction is recommended as an effective approach for alleviating lumbosacral spine pain in patients experiencing symptoms resulting from irritation or compression of a spinal nerve root.

2.
J Enzyme Inhib Med Chem ; 38(1): 2158822, 2023 Dec.
Article in English | MEDLINE | ID: mdl-36629422

ABSTRACT

Alzheimer's disease (AD) is a progressive neurodegenerative brain disease. Thus, drugs including donepezil, rivastigmine, and galantamine are not entirely effective in the treatment of this multifactorial disease. The present study evaluates eight derivatives (3a-3h) as candidates with stronger anti-AD potential but with less side effects. Reactive oxygen species (ROS) assays were used to assess oxidative stress which involve in the neurodegeneration. The neuroprotective properties of 3e against oxidative stress were done in three experiments using MTT test. The anti-AD potential was determined based on their anticholinesterase inhibition ability, determined using Ellman's method, Aß aggregation potential according to thioflavin (Th) fluorescence assay, and their antioxidative and anti-inflammatory activities. Compound 3e exhibited moderate cholinesterase inhibition activity (AChE, IC50 = 0.131 µM; BuChE, IC50 = 0.116 µM; SI = 1.13), significant inhibition of Aß(1-42) aggregation (55.7%, at 5 µM) and acceptable neuroprotective activity. Extensive analysis of in vitro and in vivo assays indicates that new cyclopentaquinoline derivatives offer promise as candidates for new anti-AD drugs.


Subject(s)
Alzheimer Disease , Neuroprotective Agents , Humans , Alzheimer Disease/drug therapy , Neuroprotection , Acetylcholinesterase/metabolism , Cholinesterase Inhibitors/pharmacology , Oxidative Stress , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use
3.
Molecules ; 27(14)2022 Jul 07.
Article in English | MEDLINE | ID: mdl-35889227

ABSTRACT

Salvia miltiorrhiza is a medicinal plant that synthesises biologically-active tanshinones with numerous therapeutic properties. An important rate-limiting enzyme in the biosynthesis of their precursors is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). This study presents the organ-specific expression profile of the S. miltiorrhiza HMGR4 gene and its sensitivity to potential regulators, viz. gibberellic acid (GA3), indole-3-acetic acid (IAA) and salicylic acid (SA). In addition, it demonstrates the importance of the HMGR4 gene, the hormone used, the plant organ, and the culture environment for the biosynthesis of tanshinones. HMGR4 overexpression was found to significantly boost the accumulation of dihydrotanshinone I (DHTI), cryptotanshinone (CT), tanshinone I (TI) and tanshinone IIA (TIIA) in roots by 0.44 to 5.39 mg/g dry weight (DW), as well as TIIA in stems and leaves. S. miltiorrhiza roots cultivated in soil demonstrated higher concentrations of the examined metabolites than those grown in vitro. GA3 caused a considerable increase in the quantity of CT (by 794.2 µg/g DW) and TIIA (by 88.1 µg/g DW) in roots. In turn, IAA significantly inhibited the biosynthesis of the studied tanshinones in root material.


Subject(s)
Salvia miltiorrhiza , Salvia , Abietanes , Acyl Coenzyme A , Coenzyme A , Furans , Oxidoreductases/metabolism , Phenanthrenes , Plant Roots/genetics , Plant Roots/metabolism , Quinones , Salvia miltiorrhiza/metabolism
4.
Plants (Basel) ; 11(14)2022 Jul 16.
Article in English | MEDLINE | ID: mdl-35890495

ABSTRACT

Salvia miltiorrhiza synthesises tanshinones with multidirectional therapeutic effects. These compounds have a complex biosynthetic pathway, whose first rate limiting enzyme is 3-hydroxy-3-methylglutaryl-coenzyme A reductase (HMGR). In the present study, a new 1646 bp fragment of the S. miltiorrhiza HMGR4 gene consisting of a promoter, 5' untranslated region and part of a coding sequence was isolated and characterised in silico using bioinformatics tools. The results indicate the presence of a TATA box, tandem repeat and pyrimidine-rich sequence, and the absence of CpG islands. The sequence was rich in motifs recognised by specific transcription factors sensitive mainly to light, salicylic acid, bacterial infection and auxins; it also demonstrated many binding sites for microRNAs. Moreover, our results suggest that HMGR4 expression is possibly regulated during flowering, embryogenesis, organogenesis and the circadian rhythm. The obtained data were verified by comparison with microarray co-expression results obtained for Arabidopsis thaliana. Alignment of the isolated HMGR4 sequence with other plant HMGRs indicated the presence of many common binding sites for transcription factors, including conserved ones. Our findings provide valuable information for understanding the mechanisms that direct transcription of the S. miltiorrhiza HMGR4 gene.

5.
Molecules ; 27(6)2022 Mar 08.
Article in English | MEDLINE | ID: mdl-35335134

ABSTRACT

The present study characterizes the 5' regulatory region of the SmMEC gene. The isolated fragment is 1559 bp long and consists of a promoter, 5'UTR and 31 nucleotide 5' fragments of the CDS region. In silico bioinformatic analysis found that the promoter region contains repetitions of many potential cis-active elements. Cis-active elements associated with the response to methyl jasmonate (MeJa) were identified in the SmMEC gene promoter. Co-expression studies combined with earlier transcriptomic research suggest the significant role of MeJa in SmMEC gene regulation. These findings were in line with the results of the RT-PCR test showing SmMEC gene expression induction after 72 h of MeJa treatment. Biphasic total tanshinone accumulation was observed following treatment of S. miltiorrhiza solid callus cultures with 50-500 µM methyl jasmonate, with peaks observed after 10-20 and 50-60 days. An early peak of total tanshinone concentration (0.08%) occurred after 20 days of 100 µM MeJa induction, and a second, much lower one, was observed after 50 days of 50 µM MeJa stimulation (0.04%). The dominant tanshinones were cryptotanshinone (CT) and dihydrotanshinone (DHT). To better understand the inducing effect of MeJa treatment on tanshinone biosynthesis, a search was performed for methyl jasmonate-responsive cis-active motifs in the available sequences of gene proximal promoters associated with terpenoid precursor biosynthesis. The results indicate that MeJa has the potential to induce a significant proportion of the presented genes, which is in line with available transcriptomic and RT-PCR data.


Subject(s)
Salvia miltiorrhiza , Abietanes , Acetates , Cyclopentanes/metabolism , Cyclopentanes/pharmacology , Oxylipins/metabolism , Oxylipins/pharmacology
6.
Genes (Basel) ; 14(1)2022 12 24.
Article in English | MEDLINE | ID: mdl-36672795

ABSTRACT

The presented study describes the regulation of the promoter region of the Salvia miltiorrhiza kaurene synthase-like gene (SmKSL) by ethylene and yeast extract. The isolated fragment is 897 bp and is composed of a promoter (763 bp), 5'UTR (109 bp), and a short CDS (25 bp). The initial in silico analysis revealed the presence of numerous putative cis-active sites for trans-factors responding to different stress conditions. However, this study examines the influence of ethylene and yeast extract on SmKSL gene expression and tanshinone biosynthesis regulation. The results of 72h RT-PCR indicate an antagonistic interaction between ethylene, provided as ethephon (0.05, 0.10, 0.25, and 0.50 mM), and yeast extract (0.5%) on SmKSL gene expression in callus cultures of S. miltiorrhiza. A similar antagonistic effect was observed on total tanshinone concentration for up to 60 days. Ethylene provided as ethephon (0.05, 0.10, 0.25, and 0.50 mM) is a weak inducer of total tanshinone biosynthesis, increasing them only up to the maximum value of 0.67 ± 0.04 mg g-1 DW (60-day induction with 0.50 mM ethephon). Among the tanshinones elicited by ethephon, cryptotanshinone (52.21%) dominates, followed by dihydrotanshinone (45.00%) and tanshinone IIA (3.79%). In contrast, the 0.5% yeast extract strongly increases the total tanshinone concentration up to a maximum value of 13.30 ± 1.09 mg g-1 DW, observed after 50 days of induction. Yeast extract and ethylene appear to activate different fragments of the tanshinone biosynthesis route; hence the primary tanshinones induced by yeast extract were cryptotanshinone (81.42%), followed by dihydrotanshinone (17.06%) and tanshinone IIA (1.52%).


Subject(s)
Salvia miltiorrhiza , Salvia miltiorrhiza/genetics , Salvia miltiorrhiza/chemistry
7.
Med Pr ; 71(5): 539-549, 2020 Sep 24.
Article in English | MEDLINE | ID: mdl-32667294

ABSTRACT

BACKGROUND: When assessing physical activity (PA), particular attention should be paid to medical university students who are taught to be health care professionals (HCPs) responsible for maintaining health in humans. However, different studies have shown that HCPs exhibit the same unhealthy behaviors as the general population. This study analyzed PA among medical university students of different faculties and their adherence to current PA recommendations. MATERIAL AND METHODS: Data from 216 medical university students of physiotherapy, dietetics and pharmacy, including males (N = 44) and females (N = 172), the mean age of 22.3±1.8 years, were collected. The International Physical Activity Questionnaire in its long form (IPAQ-LF) was used to assess and classify PA behaviors. The results were analyzed in accordance with World Health Organization recommendations regarding PA. RESULTS: Over 60% of all the students were classified as active during all-day activity. However, while analyzing PA in different domains, the same shares of all the students were still insufficiently active during leisure time, and so they did not meet the recommendation of >75 min/week of vigorous PA, >150 min/week of moderate PA or an equivalent combination. All the students self-reported PA mainly in the work and transport domains. Generally, physiotherapy students were the most active and performed PA with higher intensity. CONCLUSIONS: This study revealed a low level of leisure time PA among the students, and no habit of regular PA. Some changes in medical education should be suggested to include physical education as a long-term subject in medical school curricula. Future research is needed to investigate the exercise barriers that students perceive, which can guide future interventions aimed at improving their PA, and thereby impact on the quality of health care which they will provide. Med Pr. 2020;71(5):539-49.


Subject(s)
Exercise/psychology , Guideline Adherence/statistics & numerical data , Health Personnel/psychology , Health Personnel/statistics & numerical data , Health Promotion/standards , Students, Medical/psychology , Students, Medical/statistics & numerical data , Adult , Cross-Sectional Studies , Female , Humans , Male , Poland , Self Report , Surveys and Questionnaires , Young Adult
8.
Int J Mol Sci ; 21(11)2020 May 26.
Article in English | MEDLINE | ID: mdl-32466601

ABSTRACT

A series of new tetrahydroacridine and 3,5-dichlorobenzoic acid hybrids with different spacers were designed, synthesized, and evaluated for their ability to inhibit both cholinesterase enzymes. Compounds 3a, 3b, 3f, and 3g exhibited selective butyrylcholinesterase (EqBuChE) inhibition with IC50 values ranging from 24 to 607 nM. Among them, compound 3b was the most active (IC50 = 24 nM). Additionally, 3c (IC50 for EeAChE = 25 nM and IC50 for EqBuChE = 123 nM) displayed dual cholinesterase inhibitory activity and was the most active compound against acetylcholinesterase (AChE). Active compound 3c was also tested for the ability to inhibit Aß aggregation. Theoretical physicochemical properties of the compounds were calculated using ACD Labs Percepta and Chemaxon. A Lineweaver-Burk plot and docking study showed that 3c targeted both the catalytic active site (CAS) and the peripheral anionic site (PAS) of AChE. Moreover, 3c appears to possess neuroprotective activity and could be considered a free-radical scavenger. In addition, 3c did not cause DNA damage and was found to be less toxic than tacrine after oral administration; it also demonstrated little inhibitory activity towards hyaluronidase (HYAL), which may indicate that it possesses anti-inflammatory properties. The screening for new in vivo interactions between 3c and known receptors was realized by yeast three-hybrid technology (Y3H).


Subject(s)
Alzheimer Disease/drug therapy , Chlorobenzoates/chemistry , Cholinesterase Inhibitors/chemical synthesis , Neuroprotective Agents/chemical synthesis , Tacrine/analogs & derivatives , Amyloid beta-Protein Precursor/metabolism , Animals , Catalytic Domain , Cell Line, Tumor , Cells, Cultured , Cholinesterase Inhibitors/adverse effects , Cholinesterase Inhibitors/pharmacology , Cholinesterase Inhibitors/therapeutic use , Cholinesterases/chemistry , Cholinesterases/metabolism , Free Radical Scavengers/adverse effects , Free Radical Scavengers/chemical synthesis , Free Radical Scavengers/pharmacology , Free Radical Scavengers/therapeutic use , Humans , Hyaluronoglucosaminidase/antagonists & inhibitors , Mice , Molecular Docking Simulation , Neuroprotective Agents/adverse effects , Neuroprotective Agents/pharmacology , Neuroprotective Agents/therapeutic use , Protein Binding , Protein Multimerization/drug effects
9.
Interdiscip Sci ; 12(1): 32-43, 2020 Mar.
Article in English | MEDLINE | ID: mdl-31309397

ABSTRACT

Ent-copalyl diphosphate synthase controls the biosynthesis of gibberellin plant hormones, which in turn coordinate the expression of numerous enzymes. Some gibberellin-dependent genes encode enzymes coordinating the biosynthesis of tanshinones: diterpene derivatives with broad medical applications. New biotechnological approaches, such as metabolic engineering using naturally occurring or mutated enzymes, have been proposed to meet the growing demand for tanshinones which is currently met by the Chinese medicinal plant Salvia miltiorrhiza Bunge. These mutants may be prepared by directed evolution, saturation mutagenesis or rational enzyme design. In the presented paper, 15,257 non-synonymous variants of Arabidopsis thaliana ent-copalyl diphosphate synthase were obtained using the SNAP2 tool. The obtained forms were screened to isolate variants with potentially improved biological functions. A group of 455 mutants with potentially improved stability was isolated and subjected to further screening on the basis of ligand-substrate affinity, and both secondary structure and active site structure stability. Finally, a group of six single mutants was obtained, which were used to construct double mutants with potentially improved stability and ligand affinity. The potential influence of single mutations on protein stability and ligand affinity was evaluated by double mutant cycle analysis. Finally, the procedure was validated by in silico assessment of the experimentally verified enzyme mutants with reduced enzymatic activity.


Subject(s)
Alkyl and Aryl Transferases/metabolism , Arabidopsis/enzymology , Arabidopsis/genetics , Plant Proteins/metabolism , Alkyl and Aryl Transferases/genetics , Amino Acid Sequence , Catalytic Domain/genetics , Catalytic Domain/physiology , Mutagenesis/genetics , Mutagenesis/physiology , Phylogeny , Plant Proteins/genetics
10.
Int J Mol Sci ; 20(6)2019 Mar 15.
Article in English | MEDLINE | ID: mdl-30875925

ABSTRACT

Panax quinquefolium hairy root cultures synthesize triterpenoid saponins named ginsenosides, that have multidirectional pharmacological activity. The first rate-limiting enzyme in the process of their biosynthesis is 3-hydroxy-3-methylglutaryl CoA reductase (HMGR). In this study, a 741 bp fragment of the P. quinquefolium HMGR gene (PqHMGR), consisting of a proximal promoter, 5'UTR (5' untranslated region) and 5'CDS (coding DNA sequence) was isolated. In silico analysis of an isolated fragment indicated a lack of tandem repeats, miRNA binding sites, and CpG/CpNpG elements. However, the proximal promoter contained potential cis-elements involved in the response to light, salicylic, and abscisic acid (ABA) that was represented by the motif ABRE (TACGTG). The functional significance of ABA on P. quinquefolium HMGR gene expression was evaluated, carrying out quantitative RT-PCR experiments at different ABA concentrations (0.1, 0.25, 0.5, and 1 mg·L-1). Additionally, the effect of abscisic acid and its time exposure on biomass and ginsenoside level in Panax quinquefolium hairy root was examined. The saponin content was determined using HPLC. The 28 day elicitation period with 1 mg·L-1 ABA was the most efficient for Rg2 and Re (17.38 and 1.83 times increase, respectively) accumulation; however, the protopanaxadiol derivative content decreased in these conditions.


Subject(s)
Abscisic Acid/pharmacology , Ginsenosides/biosynthesis , Hydroxymethylglutaryl CoA Reductases/genetics , Panax/metabolism , Promoter Regions, Genetic , Chromatography, High Pressure Liquid , Cloning, Molecular , Computer Simulation , Gene Expression Regulation, Plant/drug effects , Ginsenosides/analysis , Panax/drug effects , Panax/genetics , Plant Proteins/genetics , Plant Roots/drug effects , Plant Roots/genetics , Plant Roots/metabolism
11.
Int J Mol Sci ; 20(3)2019 Jan 24.
Article in English | MEDLINE | ID: mdl-30678364

ABSTRACT

Here we report the two-step synthesis of 8 new cyclopentaquinoline derivatives as modifications of the tetrahydroacridine structure. Next, the biological assessment of each of them was performed. Based on the obtained results we identified 6-chloro-N-[2-(2,3-dihydro-1H-cyclopenta[b]quinolin-9-ylamino)-hexyl]]-nicotinamide hydrochloride (3e) as the most promising compound with inhibitory potencies against EeAChE and EqBuChE in the low nanomolar level 67 and 153 nM, respectively. Moreover, 3e compound is non-hepatotoxic, able to inhibit amyloid beta aggregation, and shows a mix-type of cholinesterase's inhibition. The mixed type of inhibition of the compound was confirmed by molecular modeling. Then, yeast three-hybrid (Y3H) technology was used to confirm the known ligand-receptor interactions. New derivatives do not show antioxidant activity (confirmed by the use of two different tests). A pKa assay method was developed to identify the basic physicochemical properties of 3e compound. A LogP assay confirmed that 3e compound fulfills Lipinsky's rule of five.


Subject(s)
Alzheimer Disease/drug therapy , Cholinesterase Inhibitors/chemical synthesis , Neuroprotective Agents/chemical synthesis , Quinolines/chemistry , Amyloid beta-Peptides/metabolism , Cell Line , Cell Line, Tumor , Cholinesterase Inhibitors/pharmacology , Humans , Molecular Docking Simulation , Neuroprotective Agents/pharmacology , Protein Binding
12.
Molecules ; 23(10)2018 Oct 17.
Article in English | MEDLINE | ID: mdl-30336634

ABSTRACT

In vitro cultivation is an effective way to increase pharmaceutical production. To increase ginsenoside production in hairy root cultures of American ginseng, the present study uses trans-anethole as an elicitor. The content of nine triterpene saponins was determined: Rb1, Rb2, Rb3, Rc, Rd, Rg1, Rg2, Re and Rf. Trans-anethole was found to stimulate saponin synthesis regardless of exposure time (24 and 72 h). Twenty-four hour exposure to 1 µmol trans-anethole in the culture medium resulted in the highest increase of total saponin content (twice that of untreated roots), and optimum accumulation of Rb-group saponins, with ginsenoside Rc dominating (8.45 mg g-1 d.w.). In contrast, the highest mean content of protopanaxatriol derivatives was obtained for 10 µmol trans-anethole. The Re metabolite predominated, reaching a concentration of 5.72 mg g-1 d.w.: a 3.9-fold increase over untreated roots. Elicitation with use of trans-anethole can therefore be an effective method of increasing ginsenoside production in shake flasks.


Subject(s)
Anisoles/pharmacology , Panax/metabolism , Saponins/biosynthesis , Triterpenes/chemistry , Allylbenzene Derivatives , Chromatography, High Pressure Liquid , Culture Media/chemistry , Panax/growth & development , Plant Roots/drug effects , Plant Roots/growth & development , Saponins/chemistry , Triterpenes/metabolism
13.
Gene ; 644: 38-48, 2018 Feb 20.
Article in English | MEDLINE | ID: mdl-29104165

ABSTRACT

The complete exploration of the regulation of gene expression remains one of the top-priority goals for researchers. As the regulation is mainly controlled at the level of transcription by promoters, study on promoters and findings are of great importance. This review summarizes forty selected databases that centralize experimental and theoretical knowledge regarding the organization of promoters, interacting transcription factors (TFs) and microRNAs (miRNAs) in many eukaryotic and prokaryotic species. The presented databases offer researchers valuable support in elucidating the regulation of gene transcription.


Subject(s)
Eukaryota/genetics , Eukaryotic Cells/physiology , Prokaryotic Cells/physiology , Promoter Regions, Genetic/genetics , Transcription, Genetic/genetics , Animals , Databases, Nucleic Acid , Humans , MicroRNAs/genetics , Transcription Factors/genetics
14.
Molecules ; 22(6)2017 May 26.
Article in English | MEDLINE | ID: mdl-28587128

ABSTRACT

One of the most effective strategies to enhance metabolite biosynthesis and accumulation in biotechnological systems is the use of elicitation processes. This study assesses the influence of different concentrations of yeast extract (YE) on ginsenoside biosynthesis in Panax quinquefolium (American ginseng) hairy roots cultivated in shake flasks and in a nutrient sprinkle bioreactor after 3 and 7 days of elicitation. The saponin content was determined using HPLC. The maximum yield (20 mg g-1 d.w.) of the sum of six examined ginsenosides (Rb1, Rb2, Rc, Rd, Re and Rg1) in hairy roots cultivated in shake flasks was achieved after application of YE at 50 mg L-1 concentration and 3 day exposure time. The ginsenoside level was 1.57 times higher than that attained in control medium. The same conditions of elicitation (3 day time of exposure and 50 mg L-1 of YE) also favourably influenced the biosynthesis of studied saponins in bioreactor cultures. The total ginsenoside content was 32.25 mg g-1 d.w. and was higher than that achieved in control medium and in shake flasks cultures. Obtained results indicated that yeast extract can be used to increase ginsenoside production in hairy root cultures of P. quinquefolium.


Subject(s)
Bioreactors , Cell Extracts/pharmacology , Ginsenosides/biosynthesis , Panax/drug effects , Panax/physiology , Plant Roots/drug effects , Plant Roots/physiology , Yeasts/chemistry
15.
Z Naturforsch C J Biosci ; 68(11-12): 482-8, 2013.
Article in English | MEDLINE | ID: mdl-24601086

ABSTRACT

The content of six ginsenosides (Rb1, Rb2, Rc, Rd, Rg1, and Re) was studied in the roots of field-grown plants, as well as in root-forming callus cultures and adventitious root cultures of Panax quinquefolium using high-performance liquid chromatography (HPLC). The highest level of saponins was isolated from root hairs (128 mg/g dry weight). The examined in vitro culture synthesized all identified saponins, although in smaller amounts than those obtained from field cultivation. Metabolites Rb1 and Re dominated in the ginseng biomass from both field crops and in vitro culture.


Subject(s)
Ginsenosides/biosynthesis , Panax/metabolism , Plant Roots/metabolism , Chromatography, High Pressure Liquid
16.
Mol Membr Biol ; 24(2): 121-34, 2007.
Article in English | MEDLINE | ID: mdl-17453419

ABSTRACT

Lysenin is 297 amino acid long toxin derived from the earthworm Eisenia foetida which specifically recognizes sphingomyelin and induces cell lysis. We synthesized lysenin gene supplemented with a polyhistidine tag, subcloned it into the pT7RS plasmid and the recombinant protein was produced in Escherichia coli. In order to obtain lysenin devoid of its lytic activity, the protein was mutated by substitution of tryptophan 20 by alanine. The recombinant mutant lysenin-His did not evoke cell lysis, although it retained the ability to specifically interact with sphingomyelin, as demonstrated by immunofluorescence microscopy and by dot blot lipid overlay and liposome binding assays. We found that the lytic activity of wild-type lysenin-His was correlated with the protein oligomerization during interaction with sphingomyelin-containing membranes and the amount of oligomers was increased with an elevation of sphingomyelin/lysenin ratio. Blue native gel electrophoresis indicated that trimers can be functional units of the protein, however, lysenin hexamers and nanomers were stabilized by chemical cross-linking of the protein and by sodium dodecyl sulfate. When incorporated into planar lipid bilayers, wild type lysenin-His formed cation-selective channels in a sphingomyelin-dependent manner. We characterized the channel activity by establishing its various open/closed states. In contrast, the mutant lysenin-His did not form channels and its correct oligomerization was strongly impaired. Based on these results we suggest that lysenin oligomerizes upon interaction with sphingomyelin in the plasma membrane, forming cation-selective channels. Their activity disturbs the ion balance of the cell, leading eventually to cell lysis.


Subject(s)
Cation Transport Proteins/chemistry , Cell Membrane/metabolism , Sphingomyelins/metabolism , Toxins, Biological/chemistry , Tryptophan/physiology , Animals , Dimerization , Erythrocytes/metabolism , Gene Expression , Histidine/chemistry , In Vitro Techniques , Oligochaeta/genetics , Protein Binding , Sheep , Toxins, Biological/genetics , Toxins, Biological/metabolism
SELECTION OF CITATIONS
SEARCH DETAIL
...