Dimethyl sulfoxide induces oxidative stress in the yeast Saccharomyces cerevisiae

Yeast perilipin Pet10p/Pln1p interacts with Erg6p in ergosterol metabolism

Lipid droplets (LD) are highly dynamic organelles specialized for the regulation of energy storage and cellular homeostasis. LD consist of a neutral lipid core surrounded by a phospholipid monolayer membrane with embedded proteins, most of which are involved in lipid homeostasis. In this study, we focused on one of the major LD proteins, sterol C24-methyltransferase, encoded by ERG6. We found that the absence of Erg6p resulted in an increased accumulation of yeast perilipin Pet10p in LD, while the disruption of PET10 was accompanied by Erg6p LD over-accumulation. An observed reciprocal enrichment of Erg6p and Pet10p in pet10Δ and erg6Δ mutants in LD, respectively, was related to specific functional changes in the LD and was not due to regulation on the expression level. The involvement of Pet10p in neutral lipid homeostasis was observed in experiments that focused on the dynamics of neutral lipid mobilization as time-dependent changes in the triacylglycerols (TAG) and steryl esters (SE) content. We found that the kinetics of SE hydrolysis was reduced in erg6Δ cells and the mobilization of SE was completely lost in mutants that lacked both Erg6p and Pet10p. In addition, we observed that decreased levels of SE in erg6Δpet10Δ was linked to an overexpression of steryl ester hydrolase Yeh1p. Lipid analysis of erg6Δpet10Δ showed that PET10 deletion altered the composition of ergosterol intermediates which had accumulated in erg6Δ. In conclusion, yeast perilipin Pet10p functionally interacts with Erg6p during the metabolism of ergosterol.

Mechanistic Insights into Cellular and Molecular Targets of Zinc Oxide Quantum Dots (ZnO QDs) in Fungal Pathogen, Candida albicans: One Drug Multi-Targeted Therapeutic Approach

Rationally designed multitargeted drugs, known as network therapeutics/multimodal drugs, have emerged as versatile therapeutic solutions to combat drug-resistant microbes. Here, we report novel mechanistic insights into cellular and molecular targets of ZnO quantum dots (QDs) against Candida albicans, a representative of fungal pathogens. Stable, monodispersed 4-6 nm ZnO QDs were synthesized using a wet chemical route, which exhibited dose-dependent inhibition on the growth dynamics of Candida. Treatment with 200 μg/mL ZnO QDs revealed an aberrant morphology and a disrupted cellular ultrastructure in electron microscopy and led to a 23% reduction in ergosterol content and a 53% increase in intracellular reactive oxygen species. Significant increase in steady-state fluorescence polarization and fluorescence lifetime decay of membrane probe 1,6-diphenyl-1,3,5-hexatriene (DPH) in treated cells, respectively, implied reduction in membrane fluidity and enhanced microviscosity. The observed reduction in passive diffusion of fluorescent Rhodamine 6G across the membrane validated the intricate relationship between ergosterol, membrane fluidity, and microviscosity. An inverse relationship existing between ergosterol biosynthetic genes, ERG11 and ERG3 in treated cells, related well with displayed higher susceptibilities. Furthermore, treated cells exhibited impaired functionality and downregulation of ABC drug efflux pumps. Multiple cellular targets of ZnO QDs in Candida were validated by in silico molecular docking. Thus, targeting ERG11, ERG3, and ABC drug efflux pumps might emerge as a versatile, nano-ZnO-based strategy in fungal therapeutics to address the challenges of drug resistance.

Central Carbon Metabolism in Candida albicans Biofilms Is Altered by Dimethyl Sulfoxide

The effect of dimethyl sulfoxide (DMSO) on fungal metabolism has not been well studied. This study aimed to evaluate, by metabolomics, the impact of DMSO on the central carbon metabolism of Candida albicans. Biofilms of C. albicans SC5314 were grown on paper discs, using minimum mineral (MM) medium, in a dynamic continuous flow system. The two experimental conditions were control and 0.03% DMSO (v/v). After 72 h of incubation (37 °C), the biofilms were collected and the metabolites were extracted. The extracted metabolites were subjected to gas chromatography-mass spectrometry (GC/MS). The experiment was conducted using five replicates on three independent occasions. The GC/MS analysis identified 88 compounds. Among the 88 compounds, the levels of 27 compounds were markedly different between the two groups. The DMSO group exhibited enhanced levels of putrescine and glutathione and decreased levels of methionine and lysine. Additionally, the DMSO group exhibited alterations in 13 metabolic pathways involved in primary and secondary cellular metabolism. Among the 13 altered pathways, seven were downregulated and six were upregulated in the DMSO group. These results indicated a differential intracellular metabolic profile between the untreated and DMSO-treated biofilms. Hence, DMSO was demonstrated to affect the metabolic pathways of C. albicans. These results suggest that DMSO may influence the results of laboratory tests when it is used as a solvent. Hence, the use of DMSO as a solvent must be carefully considered in drug research, as the effect of the researched drugs may not be reliably translated into clinical practice.

Bioanalytical sensors using the heat-transfer method HTM and related techniques

This review provides an overview on bio- and chemosensors based on a thermal transducer platform that monitors the thermal interface resistance R th between a solid chip and the supernatant liquid. The R th parameter responds in a surprisingly strong way to molecular-scale changes at the solid-liquid interface, which can be measured thermometrically, using for instance thermocouples in combination with a controllable heat source. In 2012, the effect was first observed during on-chip denaturation experiments on complementary and mismatched DNA duplexes that differ in their melting temperature. Since then, the concept is addressed as heat-transfer method, in short HTM, and numerous applications of the basic sensing principle were identified. Functionalizing the chip with bioreceptors such as molecularly imprinted polymers makes it possible to detect neurotransmitters, inflammation markers, viruses, and environmental pollutants. In combination with aptamer-type receptors, it is also possible to detect proteins at low concentrations. Changing the receptors to surface-imprinted polymers has opened up new possibilities for quantitative bacterial detection and identification in complex matrices. In receptor-free variants, HTM was successfully used to characterize lipid vesicles and eukaryotic cells (yeast strains, cancer cell lines), the latter showing spontaneous detachment under influence of the temperature gradient inherent to HTM. We will also address modifications to the original HTM technique such as M-HTM, inverted HTM, thermal wave transport analysis TWTA, and the hot-wire principle. The article concludes with an assessment of the possibilities and current limitations of the method, together with a technological forecast.

Biodegradable Grubbs-Loaded Artificial Organelles for Endosomal Ring-Closing Metathesis

The application of transition-metal catalysts in living cells presents a promising approach to facilitate reactions that otherwise would not occur in nature. However, the usage of metal complexes is often restricted by their limited biocompatibility, toxicity, and susceptibility to inactivation and loss of activity by the cell's defensive mechanisms. This is especially relevant for ruthenium-mediated reactions, such as ring-closing metathesis. In order to address these issues, we have incorporated the second-generation Hoveyda-Grubbs catalyst (HGII) into polymeric vesicles (polymersomes), which were composed of biodegradable poly(ethylene glycol)-b-poly(caprolactone-g-trimethylene carbonate) [PEG-b-P(CL-g-TMC)] block copolymers. The catalyst was either covalently or non-covalently introduced into the polymersome membrane. These polymersomes were able to act as artificial organelles that promote endosomal ring-closing metathesis for the intracellular generation of a fluorescent dye. This is the first example of the use of a polymersome-based artificial organelle with an active ruthenium catalyst for carbon-carbon bond formation.

Production of PETase by engineered Yarrowia lipolytica for efficient poly(ethylene terephthalate) biodegradation

There has been a growing interest in poly(ethylene terephthalate) PET degradation studies in the last few years due to its widespread use and large-scale plastic waste accumulation in the environment. One of the most promising enzymatic methods in the context of PET degradation is the use of PETase from Ideonella sakaiensis, which has been reported to be an efficient enzyme for hydrolysing ester bonds in PET. In our study, we expressed a codon-optimized PETase gene in the yeast Yarrowia lipolytica. The obtained strain was tested for its ability to degrade PET directly in culture, and a screening of different supplements that might raise the level of PET hydrolysis was performed. We also carried out long-term cultures with PET film, the surface of which was examined by scanning electron microscopy. The efficiency of PET degradation was tested based on the concentration of degradation products released, and the results showed that supplementation of the culture with olive oil resulted in 66 % higher release of terephthalic acid into the medium compared to the mutant culture without supplementation. The results indicate the possibility of ethylene glycol uptake by both strains, and, additionally, the PETase produced by the newly engineered strain hydrolyses MHET. The structure of the PET film after culture with the modified strain, meanwhile, had numerous surface defects, cracks, and deformations.

Synchronized, Spontaneous, and Oscillatory Detachment of Eukaryotic Cells: A New Tool for Cell Characterization and Identification

Despite the importance of cell characterization and identification for diagnostic and therapeutic applications, developing fast and label-free methods without (bio)-chemical markers or surface-engineered receptors remains challenging. Here, we exploit the natural cellular response to mild thermal stimuli and propose a label- and receptor-free method for fast and facile cell characterization. Cell suspensions in a dedicated sensor are exposed to a temperature gradient, which stimulates synchronized and spontaneous cell-detachment with sharply defined time-patterns, a phenomenon unknown from literature. These patterns depend on metabolic activity (controlled through temperature, nutrients, and drugs) and provide a library of cell-type-specific indicators, allowing to distinguish several yeast strains as well as cancer cells. Under specific conditions, synchronized glycolytic-type oscillations are observed during detachment of mammalian and yeast-cell ensembles, providing additional cell-specific signatures. These findings suggest potential applications for cell viability analysis and for assessing the collective response of cancer cells to drugs.

Comparative study of the antioxidant activity of the essential oils of five plants against the H2O2 induced stress in Saccharomyces cerevisiae

The purpose of this work was to investigate the protective effect of five essential oils (EOs); Rosmarinus officinalis, Thymus vulgaris, Origanum compactum Benth., Eucalyptus globulus Labill. and Ocimum basilicum L.; against oxidative stress induced by hydrogen peroxide in Saccharomyces cerevisiae. The chemical composition of the EOs was analyzed by gas chromatography (GC) and gas chromatography-mass spectrometry (GC/MS). The in vitro antioxidant activity was evaluated and the protective effect of EOs was investigated. Yeast cells were pretreated with different concentrations of EOs (6.25–25 µg/ml) for an hour then incubated with H₂O₂ (2 mM) for an additional hour. Cell viability, antioxidants (Catalase, Superoxide dismutase and Glutathione reductase) and metabolic (Succinate dehydrogenase) enzymes, as well as the level of lipid peroxidation (LPO) and protein carbonyl content (PCO) were evaluated. The chemical composition of EOs has shown the difference qualitatively and quantitatively. Indeed, O. compactum mainly contained Carvacrol, O. basilicum was mainly composed of Linalool, T. vulgaris was rich in thymol, R. officinalis had high α-Pinene amount and for E. globulus, eucalyptol was the major compound. The EOs of basil, oregano and thyme were found to possess the highest amount of total phenolic compounds. Moreover, they have shown the best protective effect on yeast cells against oxidative stress induced by H₂O₂. In addition, in a dose dependent manner of EOs in yeast medium, treated cells had lower levels of LPO, lower antioxidant and metabolic enzymes activity than cells exposed to H₂O₂ only. The cell viability was also improved. It seems that the studied EOs are efficient natural antioxidants, which can be exploited to protect against damages and serious diseases related to oxidative stress.

Musings in the twilight of my career

I present a summary of my research during the last few decades of research which focused on understanding the biochemical basis for maintaining an optimum metabolism to support long-term health. I realized that adequate levels of ∼40 vitamins and minerals needed as cofactors in thousands of metabolic reactions were critical for maintaining a healthy metabolism, and thus for longevity and prevention of chronic disease. Inadequate dietary intake of vitamins and minerals accelerates the risk of aging-associated diseases, leading to insidious damage. The Triage Theory provides a mechanistic rationale for such damage: shortage of a nutrient triggers a built-in rationing mechanism that allocates the scarce nutrient to proteins needed for immediate survival (survival proteins), at the expense of those needed for long-term survival (longevity proteins). Many as-yet-unknown longevity vitamins and proteins likely remain to be discovered. The fiber and nutrient-rich CHORI-bar was developed to fill gaps in inadequate diets; it yielded broadscale metabolic improvements. The health-related damages resulting from vitamin D deficiency and the positive effects of vitamin D supplementation were connected to numerous health-related problems, including the higher level of deficiency in people of color residing at northern latitudes. In general, prevention of degenerative diseases of aging requires expertise in metabolism, nutrition, biochemistry and regulatory functions.

Dosing metric in cellular experiments: The mol/cell metric has its limitations

It has been argued that the mol/cell metric is more universal than concentration of the toxic agent since in many cases the effect of dose expressed as mol/cell is independent of ex-perimental setup. We confirmed it for hemolysis of erythrocytes in phosphate-buffered saline induced by hypochlorite where the amount of femtomoles/cell of hypochlorite needed for 50% hemolysis was independent of erythrocyte concentration. However, in the presence of blood plasma this metric became dependent on cell concentration. Similarly, the effect of 3-bromopyruvic acid (3-BP) on PEO1 cells as a function of mol/cell ratio depended on the volume of the 3-BP containing medium, due to the reaction of 3-BP with components of the medium. Hemolytic amounts of sodium dodecyl sulfate and Triton X-100 expressed as mol/cell decreased with increasing cell concentration while the effect of DMSO on the viability of a constant number of fibroblasts was independent of the volume of DMSO-containing medium. These results demonstrate that the mol/cell metric is still dependent on experimental conditions when the toxic agent interacts with components of the medium or when its physical state is modified by the target cells, and the effect is independent of the mol/per cell ratio for high excess of a cell damaging agent.

Effectiveness and safety of topical amphotericin B in 30% dimethyl sulfoxide cream versus 30% dimethyl sulfoxide cream for nondermatophyte onychomycosis treatment: A pilot study

BACKGROUND

Although topical amphotericin B cream is effective for the treatment of nondermatophyte mold onychomycosis in vitro, studies of its effectiveness and safety in vivo are limited.

OBJECTIVES

We studied the effectiveness and safety of topical 0.3% amphotericin B in 30% dimethyl sulfoxide cream (amphotericin B cream) in nondermatophyte mold onychomycosis using the vehicle cream 30% dimethyl sulfoxide cream as control.

METHODS

This randomized controlled study was conducted between January 2019 and November 2020. Patients diagnosed with nondermatophyte mold onychomycosis were randomly divided into two groups of ten patients each: one treated with amphotericin B cream and the other with the vehicle cream. Clinical and mycological cure as well as safety were evaluated.

RESULTS

Ten patients each treated with amphotericin B cream and the vehicle cream were included in the study, but only nine patients in the vehicle cream group were available for follow up. All the 19 evaluable patients had distal lateral subungual onychomycosis and the great toenails were affected in 18 (94.7%) of these. Mycological cure was achieved in 8 (80%) patients treated with amphotericin B cream and in 4 (44.4%) patients using the control (vehicle) cream. Clinical cure was achieved in 7 (70%) patients treated with amphotericin B cream, but only in 2 (22.2%) patients on the control cream. No adverse events were observed.

LIMITATIONS

The small sample size and the fact that PCR fungal identification that provides accurate identification of fungal species was not performed are limitations of our study.

CONCLUSION

Topical amphotericin B cream was both very effective and safe in the treatment nondermatophyte mold onychomycosis. The control (vehicle) cream containing 30% dimethyl sulfoxide also demonstrated some antifungal activity.

Genetic interaction between RLM1 and F-box motif encoding gene SAF1 contributes to stress response in Saccharomyces cerevisiae

BACKGROUND

Stress response is mediated by the transcription of stress-responsive genes. The F-box motif protein Saf1p is involved in SCF-E3 ligase mediated degradation of the adenine deaminase, Aah1p upon nutrient stress. The four transcription regulators, BUR6, MED6, SPT10, SUA7, are listed for SAF1 in the genome database of Saccharomyces cerevisiae. Here in this study, we carried out an in-silico analysis of gene expression and transcription factor databases to understand the regulation of SAF1 expression during stress for hypothesis and experimental analysis.

RESULT

An analysis of the GEO profile database indicated an increase in SAF1 expression when cells were treated with stress agents such as Clioquinol, Pterostilbene, Gentamicin, Hypoxia, Genotoxic, desiccation, and heat. The increase in expression of SAF1 during stress conditions correlated positively with the expression of RLM1, encoding the Rlm1p transcription factor. The expression of AAH1 encoding Aah1p, a Saf1p substrate for ubiquitination, appeared to be negatively correlated with the expression of RLM1 as revealed by an analysis of the Yeastract expression database. Based on analysis of expression profile and regulatory association of SAF1 and RLM1, we hypothesized that inactivation of both the genes together may contribute to stress tolerance. The experimental analysis of cellular growth response of cells lacking both SAF1 and RLM1 to selected stress agents such as cell wall and osmo-stressors, by spot assay indicated stress tolerance phenotype similar to parental strain however sensitivity to genotoxic and microtubule depolymerizing stress agents.

CONCLUSIONS

Based on in-silico and experimental data we suggest that SAF1 and RLM1 both interact genetically in differential response to genotoxic and general stressors.

Development of an automated yeast-based spectrophotometric method for toxicity screening: Application to ionic liquids, GUMBOS, and deep eutectic solvents

Saccharomyces cerevisiae has been used as a eukaryotic model organism for studying the toxic effects of various compounds. In this context, an automated spectrophotometric method based on the enzymatic reduction of methylene blue dye to a colorless product by living yeast cells was implemented in a sequential injection analysis system. Loss of yeast viability/impaired metabolic activity was monitored by an increase in optical density at 664 nm. To prove the usefulness of this approach, the toxicity of ILs (ionic liquids), GUMBOS (group of uniform materials based on organic salts), and DESs (deep eutectic solvents) was examined. Differences obtained between IC₅₀ values confirmed the impact of structural elements on each compounds' toxicity. While DESs appeared to be less toxic than ILs, GUMBOS were found to be among the most toxic compounds to yeast cells and thus can be viewed as promising antimicrobial candidates. The automated methodology showed satisfactory repeatability and reproducibility (RSD < 9%), which is in good agreement with Green Chemistry principles. In fact, the method required consumption of only 40 μL of reagents and produced less than 2 mL of effluents per cycle. Thus, the developed assay can be used as an alternative tool for toxicity screening.

Magnetic nanoparticle mediated-gene delivery for simpler and more effective transformation of Pichia pastoris

The introduction of exogenous DNA into a cell can be used to produce large quantities of protein. Here, we describe a novel gene delivery method for Pichia pastoris based on recombinant DNA delivery using magnetic nanoparticles (MNPs) under magnetic forces. For this purpose, a linear plasmid (pGKB-GFP) containing the Green Fluorescent Protein (GFP) gene is loaded on polyethyleneimine-coated iron oxide (Fe3O4@PEI) MNPs at doses that are non-toxic to the yeast cells. The pGKB-GFP loaded MNPs combined with enhancer PEI (Fe3O4@PEI + pGKB-GFP + PEI) are directly transferred to non-competent cells. An effective GFP expression was observed by the selection of antibiotic-resistant yeast cells and heterologous gene integration into the P. pastoris genome was provided. This method, which is very simple, effective, and advanced equipment-free compared to traditional methods, uses smaller amounts of DNA and the process can be performed in a shorter time. The suggested method might also be adapted for the transformation of other yeast species.

A genome-wide portrait of pervasive drug contaminants

Using a validated yeast chemogenomic platform, we characterized the genome-wide effects of several pharmaceutical contaminants, including three N-nitrosamines (NDMA, NDEA and NMBA), two related compounds (DMF and 4NQO) and several of their metabolites. A collection of 4800 non-essential homozygous diploid yeast deletion strains were screened in parallel and the strain abundance was quantified by barcode sequencing. These data were used to rank deletion strains representing genes required for resistance to the compounds to delineate affected cellular pathways and to visualize the global cellular effects of these toxins in an easy-to-use searchable database. Our analysis of the N-nitrosamine screens uncovered genes (via their corresponding homozygous deletion mutants) involved in several evolutionarily conserved pathways, including: arginine biosynthesis, mitochondrial genome integrity, vacuolar protein sorting and DNA damage repair. To investigate why NDMA, NDEA and DMF caused fitness defects in strains lacking genes of the arginine pathway, we tested several N-nitrosamine metabolites (methylamine, ethylamine and formamide), and found they also affected arginine pathway mutants. Notably, each of these metabolites has the potential to produce ammonium ions during their biotransformation. We directly tested the role of ammonium ions in N-nitrosamine toxicity by treatment with ammonium sulfate and we found that ammonium sulfate also caused a growth defect in arginine pathway deletion strains. Formaldehyde, a metabolite produced from NDMA, methylamine and formamide, and which is known to cross-link free amines, perturbed deletion strains involved in chromatin remodeling and DNA repair pathways. Finally, co-administration of N-nitrosamines with ascorbic or ferulic acid did not relieve N-nitrosamine toxicity. In conclusion, we used parallel deletion mutant analysis to characterize the genes and pathways affected by exposure to N-nitrosamines and related compounds, and provide the data in an accessible, queryable database.

Impact of glycerol feeding profiles on STEAP1 biosynthesis by Komagataella pastoris using a methanol-inducible promoter

Currently, the lack of reliable strategies for the diagnosis and treatment of cancer makes the identification and characterization of new therapeutic targets a pressing matter. Several studies have proposed the Six Transmembrane Epithelial Antigen of the Prostate 1 (STEAP1) as a promising therapeutic target for prostate cancer. Although structural and functional studies may provide deeper insights on the role of STEAP1 in cancer, such techniques require high amounts of purified protein through biotechnological processes. Based on the results presented, this work proposes the application, for the first time, of a fed-batch profile to improve STEAP1 biosynthesis in mini-bioreactor Komagataella pastoris X-33 Mut⁺ methanol-induced cultures, by evaluating three glycerol feeding profiles-constant, exponential, and gradient-during the pre-induction phase. Interestingly, different glycerol feeding profiles produced differently processed STEAP1. This platform was optimized using a combination of chemical chaperones for ensuring the structural stabilization and appropriate processing of the target protein. The supplementation of culture medium with 6 % (v/v) DMSO and 1 M proline onto a gradient glycerol/constant methanol feeding promoted increased biosynthesis levels of STEAP1 and minimized aggregation events. Deglycosylation assays with peptide N-glycosidase F showed that glycerol constant feed is associated with an N-glycosylated pattern of STEAP1. The biological activity of recombinant STEAP1 was also validated, once the protein enhanced the proliferation of LNCaP and PC3 cancer cells, in comparison with non-tumoral cell cultures. This methodology could be a crucial starting point for large-scale production of active and stable conformation of recombinant human STEAP1. Thus, it could open up new strategies to unveil the structural rearrangement of STEAP1 and to better understand the biological role of the protein in cancer onset and progression.

Determination of the Phytochemical Composition and Antioxidant Potential of Eugenia copacabanensis and Myrciaria tenella Leaves (Myrtaceae) Using a Saccharomyces cerevisiae Model

Eugenia copacabanensis and Myrciaria tenella are present in restingas of the Atlantic Forest, but little information is available about their chemical and biological potential. In this context, the hexane, dichloromethane, ethyl acetate and butanol fractions from the leaves of methanolic extract were analyzed by GC/MS and HPLC-DAD and the antioxidant potential was determined by DPPH and ABTS assays and using a Saccharomyces cerevisiae model. Dereplication allowed the identification of 68 compounds, 42 and 41 of which, respectively, are first reported here for E. copacabanensis and M. tenella. In vivo results revealed that the ethyl acetate and butanol fractions showed expressive antioxidant protection in the BY4741 and Δgsh1 strains, with greater impact on glutathione-deficient cells. With a high diversity of phenolic compounds, these polar fractions of E. copacabanensis and M. tenella leaves are potential protectors against intracellular oxidative stress.

Replication Stress Induces Global Chromosome Breakage in the Fragile X Genome

Fragile X syndrome (FXS) is a neurodevelopmental disorder caused by mutations in the FMR1 gene and deficiency of a functional FMRP protein. FMRP is known as a translation repressor whose nuclear function is not understood. We investigated the global impact on genome stability due to FMRP loss. Using Break-seq, we map spontaneous and replication stress-induced DNA double-strand breaks (DSBs) in an FXS patient-derived cell line. We report that the genomes of FXS cells are inherently unstable and accumulate twice as many DSBs as those from an unaffected control. We demonstrate that replication stress-induced DSBs in FXS cells colocalize with R-loop forming sequences. Exogenously expressed FMRP in FXS fibroblasts ameliorates DSB formation. FMRP, not the I304N mutant, abates R-loop-induced DSBs during programmed replication-transcription conflict. These results suggest that FMRP is a genome maintenance protein that prevents R-loop accumulation. Our study provides insights into the etiological basis for FXS.

Chemical characterization and in vivo antioxidant activity of parsley (Petroselinum crispum) aqueous extract

Twenty-nine flavonoid glycosides were identified in the aqueous extract (PC) of Petroselinum crispum var. crispum leaves and apiin, the major compound, was isolated thereof. Apigenin was obtained (90% purity) by the hydrolysis of apiin. A high content of phenolics (12.49 ± 1.70 mg GAE per g of parsley extract - Folin-Ciocalteu method) and total flavonoids (15.05 ± 2.20 mg of quercetin equivalents per g of parsley extract - aluminum chloride method) was quantified in P. crispum, as well as high antioxidant activity ((EC50 - 15.50 mg mL-1, DPPH method) and (189.8 mM Fe(ii) per mg of dry plant aqueous extract - FRAP method)). In vivo analysis with Saccharomyces cerevisiae cells showed low toxicity of the aqueous extract of parsley, however, it revealed a high dose-dependent antioxidant potential, mainly in the lipoperoxidation assay. In addition, flavonoid apiin also showed antioxidant action on yeast cells under oxidative stress in the cell viability assay (0.1 mM) and lipid peroxidation (0.01 and 0.1 mM), while apigenin was slightly antioxidant. Therefore, it is likely that the antioxidant activity of apiin is related to the total antioxidant capacity of parsley.

Dimethyl sulfoxide stimulates the AhR-Jdp2 axis to control ROS accumulation in mouse embryonic fibroblasts

The aryl hydrocarbon receptor (AhR) is a ligand-binding protein that responds to environmental aromatic hydrocarbons and stimulates the transcription of downstream phase I enzyme–related genes by binding the cis element of dioxin-responsive elements (DREs)/xenobiotic-responsive elements. Dimethyl sulfoxide (DMSO) is a well-known organic solvent that is often used to dissolve phase I reagents in toxicology and oxidative stress research experiments. In the current study, we discovered that 0.1% DMSO significantly induced the activation of the AhR promoter via DREs and produced reactive oxygen species, which induced apoptosis in mouse embryonic fibroblasts (MEFs). Moreover, Jun dimerization protein 2 (Jdp2) was found to be required for activation of the AhR promoter in response to DMSO. Coimmunoprecipitation and chromatin immunoprecipitation studies demonstrated that the phase I–dependent transcription factors, AhR and the AhR nuclear translocator, and phase II–dependent transcription factors such as nuclear factor (erythroid-derived 2)–like 2 (Nrf2) integrated into DRE sites together with Jdp2 to form an activation complex to increase AhR promoter activity in response to DMSO in MEFs. Our findings provide evidence for the functional role of Jdp2 in controlling the AhR gene via Nrf2 and provide insights into how Jdp2 contributes to the regulation of ROS production and the cell spreading and apoptosis produced by the ligand DMSO in MEFs.

Dimethyl Sulfoxide: Morphological, Histological, and Molecular View on Developing Chicken Liver

Dimethyl sulfoxide (DMSO) is widely used as a solvent for small hydrophobic drug molecules. However, the safe volume allowing to avoid its embryotoxic effect has been poorly studied. In this study, we documented the effects of dimethyl sulfoxide (DMSO) in the developing chicken embryo at morphological, histological, and molecular levels. We focused on the developing chicken liver as the main organ involved in the process of detoxification. In our study, 100% DMSO was administered subgerminally onto the eggshell membrane (membrana papyracea) at various volumes (5, 10, 15, 20, 25, 30, 35, and 50 µL) on 4th embryonic day (ED). We focused on histopathological alterations of the liver structure, and noticed the overall impact of DMSO on developing chicken embryos (embryotoxicity, malformation). At the molecular level, we studied cytochrome P450 complex (CYP) isoform's activities in relation to changes of CYP1A5, CYP3A37, and CYP3A80 gene expression. Total embryotoxicity after application of different doses of DMSO on ED 4, and the embryo lethality increased with increasing DMSO amounts. Overall mortality after DMSO administration ranged below 33%. Mortality was increased with higher amounts of DMSO, mainly from 20 µL. The highest mortality was observed for the highest dose of DMSO over 35 µL. The results also showed a decrease in body weight with increased application volumes of DMSO. At the histological level, we observed mainly the presence of lipid droplets and dilated bile canaliculi and sinusoids in samples over the administration of 25 µL of DMSO. While these findings were not statistically significant, DMSO treatment caused a significant different up-regulation of mRNA expression in all studied genes. For CYP1A5, CYP3A37, and CYP3A80 DMSO volumes needed were 15 µL, 10 µL, and 20 µL, respectively. A significant down-regulation of all studied CYP isoform was detected after application of a DMSO dose of 5 µL. Regarding the morphological results, we can assume that the highest safe dose of DMSO without affecting chicken embryo development and its liver is up to 10 µL. This conclusion is corroborated with the presence of number of malformations and body weight reduction, which correlates with histological findings. Moreover, the gene expression results showed that even the lowest administered DMSO volume could affect hepatocytes at the molecular level causing down-regulation of cytochrome P450 complex (CYP1A5, CYP3A37, CYP3A80).

Chemical Composition, Antioxidant and Antimicrobial Activity of Raspberry, Blackberry and Raspberry-Blackberry Hybrid Leaf Buds

In our investigation, the chemical composition and bioactive potential of leaf buds of raspberry, blackberry, and a raspberry-blackberry hybrid were determined. Antioxidant and antimicrobial properties were tested in water (W), ethanol-water (EW), and glycerol-water (GW) extracts from the buds. These plant organs contain relatively large amounts of minerals, especially Fe. The total antioxidant capacity (TAC) measured by the ABTS and DPPH methods ranged from 2.86 to 12.19 and 6.75 to 24.26 mmol per 100 g fresh weight (FW) of buds, respectively. TAC values were generally higher in the raspberry than in the case of blackberry and raspberry-blackberry hybrid extracts. The antioxidant properties of the extracts were strongly positively correlated with their content of total phenolic (TP). No such relationship was noted for ascorbic acid (AA), whose concentration in all extracts was at a similarly low level. Antioxidant properties determined in vitro were confirmed for the GW extract from raspberry leaf buds in biological test based on the growth parameters of Δsod1 Saccharomyces cerevisiae mutant cells in hypertonic medium. The extracts also exhibited strong antibacterial properties against Staphylococcus aureus and Enterococcus faecalis and weaker against Enterobacter aerogenes. The studied leaf buds could be therefore an unconventional source of minerals, natural antioxidants and antibacterial compounds with potential applications in the food, pharmaceutical, and cosmetics industries.

Characterization of Novel Synthetic Polyphenols: Validation of Antioxidant and Vasculoprotective Activities

Antioxidant compounds, including polyphenols, have therapeutic effects because of their anti-inflammatory, antihypertensive, antithrombotic and antiproliferative properties. They play important roles in protecting the cardiovascular and neurological systems, by having preventive or protective effects against free radicals produced by either normal or pathological metabolism in such systems. For instance, resveratrol, a well-known potent antioxidant, has a counteracting effect on the excess of reactive oxygen species (ROS) and has a number of therapeutic benefits, like anti-inflammatory, anti-cancer and cardioprotective activities. Based on previous work from our group, and on the most frequent OH substitutions of natural polyphenols, we designed two series of synthetically accessible bis-polyhydroxyphenyl derivatives, separated by amide or urea linkers. These compounds exhibit high antioxidant ability (oxygen radical absorbance capacity (ORAC) assay) and interesting radical scavenging activity (RSA) values (2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) and α,α-diphenyl-β-picrylhydrazyl (DPPH) tests). Some of the best polyphenols were evaluated in two biological systems, endothelial cells (in vitro) and whole aorta (ex vivo), highly susceptible for the deleterious effects of prooxidants under different inflammatory conditions, showing protection against oxidative stress induced by inflammatory stimuli relevant in cardiovascular diseases, i.e., Angiotensin II and IL-1β. Selected compounds also showed strong in vivo antioxidant properties when evaluated in the model organism Saccharomyces cerevisiae.

Ethanol and H2O2 stresses enhance lipid production in an oleaginous Rhodotorula toruloides thermotolerant mutant L1-1

Stress tolerance is a desired characteristic of yeast strains for industrial applications. Stress tolerance has been well described in Saccharomyces yeasts but has not yet been characterized in oleaginous Rhodotorula yeasts even though they are considered promising platforms for lipid production owing to their outstanding lipogenicity. In a previous study, the thermotolerant strain L1–1 was isolated from R. toruloides DMKU3-TK16 (formerly Rhodosporidium toruloides). In this study, we aimed to further examine the ability of this strain to tolerate other stresses and its lipid productivity under various stress conditions. We found that the L1–1 strain could tolerate not only thermal stress but also oxidative stress (ethanol and H2O2), osmotic stress (glucose) and a cell membrane disturbing reagent (DMSO). Our results also showed that the L1–1 strain exhibited enhanced ability to maintain ROS homeostasis, stronger cell wall strength and increased levels of unsaturated membrane lipids under various stresses. Moreover, we also demonstrated that ethanol-induced stress significantly increased the lipid productivity of the thermotolerant L1–1. The thermotolerant L1–1 was also found to produce a higher lipid titer under the dual ethanol-H2O2 stress than under non-stress conditions. This is the first report to indicate that ethanol stress can induce lipid production in an R. toruloides thermotolerant strain.

Characterization of Antimicrobial, Antioxidant, and Leishmanicidal Activities of Schiff Base Derivatives of 4-Aminoantipyrine

Our main interest is the characterization of compounds to support the development of alternatives to currently marketed drugs that are losing effectiveness due to the development of resistance. Schiff bases are promising biologically interesting compounds having a wide range of pharmaceutical properties, including anti-inflammatory, antipyretic, and antimicrobial activities, among others. In this work, we have synthesized 12 Schiff base derivatives of 4-aminoantipyrine. In vitro antimicrobial, antioxidant, and cytotoxicity properties are analyzed, as well as in silico predictive adsorption, distribution, metabolism, and excretion (ADME) and bioactivity scores. Results identify two potential Schiff bases: one effective against E. faecalis and the other with antioxidant activity. Both have reasonable ADME scores and provides a scaffold for developing more effective compounds in the future. Initial studies are usually limited to laboratory in vitro approaches, and following these initial studies, much research is needed before a drug can reach the clinic. Nevertheless, these laboratory approaches are mandatory and constitute a first filter to discriminate among potential drug candidates and chemical compounds that should be discarded.

A dose-dependent effect of dimethyl sulfoxide on lipid content, cell viability and oxidative stress in 3T3-L1 adipocytes

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Depending on the concentration, dimethyl sulfoxide (DMSO) can be toxic to cells.

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3T3-L1 adipocytes are a well-established model to study anti-obesity properties.

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DMSO doses ≥1% reduced cell viability and promoted cell damage in 3T3-L1 adipocytes.

Dimethyl sulfoxide (DMSO) is an effective solvent and cytoprotectant agent that can induce diverse actions in experimental settings, ranging from metabolic stress to cytotoxic effects depending on the concentration used. Therefore, for the quality of experiments and reproducibility of results it is essential to establish a precise and non-toxic dose of DMSO within a specific cell system. 3T3-L1 adipocytes, represent a well-established in vitro cell model used to assess the anti-obesity potential of extracts and compounds. Although DMSO is commonly used as a solvent for these experiments, there is limited data available on the compounding effects of using DMSO. The purpose of this study was to assess a concentration-dependent effect of DMSO on lipid content, cell viability and oxidative damage in 3T3-L1 adipocytes. Results showed that DMSO at doses ≥ 0.1% increased mitochondrial membrane potential as measured by JC-1 fluorescent staining, while doses ≥ 10% reduced the lipid content in matured adipocytes. Consistently, higher doses significantly reduced cell viability, elevated reactive oxygen species levels, depleted intracellular glutathione levels, and accelerated apoptosis and cell necrosis. An interesting finding was that a DMSO dose of 0.01% improved glutathione content of 3T3-L1 adipocytes and had minimal effects on cell viability, apoptosis or and necrosis, supporting its antioxidant effect. Therefore, this study provides compelling evidence that precaution should be taken when assessing compounds dissolved in DMSO, particularly doses ≥1% that were shown to induce oxidative stress in 3T3-L1 adipocytes.

CD4+ T cell activation, function, and metabolism are inhibited by low concentrations of DMSO

Dimethyl sulfoxide (DMSO) is a polar organic solvent used in a wide range of biological applications. DMSO is routinely used as a cryoprotectant for long-term cell freezing as well as to dissolve peptides and drugs for immune cell functional assays. Here, human CD4⁺ T cell activation, cytokine production, proliferation, and metabolism were investigated after stimulation in the presence of 0.01% to 1%, DMSO, representing concentrations commonly used in vitro. Surface expression of the activation markers CD69, CD25 and CD154 after polyclonal activation of CD4⁺ T cells was inhibited by 0.25% or higher concentrations of DMSO. The frequencies of IL-21⁺, IL-4⁺, and IL-22⁺ CD4⁺ T cells, following polyclonal activation were variably inhibited by DMSO at concentrations ranging from 0.25% to 1%, whereas IFNγ⁺ cells were unaffected. CD4⁺ T cell proliferation after anti-CD3 or antigen stimulation was inhibited by 0.5% DMSO and abolished by 1% DMSO. After polyclonal stimulation, glucose uptake was inhibited in the presence of 1% DMSO, but only minor effects on CD4⁺ T cell respiration were observed. Consistent with the immune effects, the gene expression of early signaling and activation pathways were inhibited in CD4⁺ T cells in the presence of 1% DMSO. Our study revealed that DMSO at concentrations generally used for in vitro studies of T cells impacts multiple features of T cell function. Therefore, we urge care when adding DMSO-containing preparations to T cell cultures.

Importance of Proteasome Gene Expression during Model Dough Fermentation after Preservation of Baker's Yeast Cells by Freezing

Freeze-thaw stress causes various types of cellular damage, survival and/or proliferation defects, and metabolic alterations. However, the mechanisms underlying how cells cope with freeze-thaw stress are poorly understood. Here, model dough fermentations using two baker's yeast strains, 45 and YF, of Saccharomyces cerevisiae were compared after 2 weeks of cell preservation in a refrigerator or freezer. YF exhibited slow fermentation after exposure to freeze-thaw stress due to low cell viability. A DNA microarray analysis of the YF cells during fermentation revealed that the genes involved in oxidative phosphorylation were relatively strongly expressed, suggesting a decrease in the glycolytic capacity. Furthermore, we found that mRNA levels of the genes that encode the components of the proteasome complex were commonly low, and ubiquitinated proteins were accumulated by freeze-thaw stress in the YF strain. In the cells with a laboratory strain background, treatment with the proteasome inhibitor MG132 or the deletion of each transcriptional activator gene for the proteasome genes (RPN4, PDR1, or PDR3) led to marked impairment of model dough fermentation using the frozen cells. Based on these data, proteasomal degradation of freeze-thaw-damaged proteins may guarantee high cell viability and fermentation performance. We also found that the freeze-thaw stress-sensitive YF strain was heterozygous at the PDR3 locus, and one of the alleles (A148T/A229V/H336R/L541P) was shown to possess a dominant negative phenotype of slow fermentation. Removal of such responsible mutations could improve the freeze-thaw stress tolerance and the fermentation performance of baker's yeast strains, as well as other industrial S. cerevisiae strains.IMPORTANCE The development of freezing technology has enabled the long-term preservation and long-distance transport of foods and other agricultural products. Fresh yeast, however, is usually not frozen because the fermentation performance and/or the viability of individual cells is severely affected after thawing. Here, we demonstrate that proteasomal degradation of ubiquitinated proteins is an essential process in the freeze-thaw stress responses of S. cerevisiae Upstream transcriptional activator genes for the proteasome components are responsible for the fermentation performance after freezing preservation. Thus, this study provides a potential linkage between freeze-thaw stress inputs and the transcriptional regulatory network that might be functionally conserved in higher eukaryotes. Elucidation of the molecular targets of freeze-thaw stress will contribute to advances in cryobiology, such as freezing preservation of human cells, tissues, and embryos for medical purposes and breeding of industrial microorganisms and agricultural crops that adapt well to low temperatures.

Multi-environment fitness landscapes of a tRNA gene

A fitness landscape (FL) describes the genotype-fitness relationship in a given environment. To explain and predict evolution, it is imperative to measure the FL in multiple environments because the natural environment changes frequently. Using a high-throughput method that combines precise gene replacement with next-generation sequencing, we determine the in vivo FL of a yeast tRNA gene comprising over 23,000 genotypes in four environments. Although genotype-by-environment interaction (G×E) is abundantly detected, its pattern is so simple that we can transform an existing FL to that in a new environment with fitness measures of only a few genotypes in the new environment. Under each environment, we observe prevalent, negatively biased epistasis between mutations (G×G). Epistasis-by-environment interaction (G×G×E) is also prevalent, but trends in epistasis difference between environments are predictable. Our study thus reveals simple rules underlying seemingly complex FLs, opening the door to understanding and predicting FLs in general.

Quantification of differential efficacy of chemical chaperones in ameliorating solubilization and folding of zebrafish dihydrofolate reductase

Protein aggregation is a major hindrance in many in vivo and in vitro studies of proteins. It results in the formation of inclusion bodies and non-functional aggregates. Chemical chaperones also known as osmolytes which are accumulated during the stress conditions in the cells can influence the protein stability through various mechanisms. They act as osmoprotectants and contribute to the protein folding by enabling the protein to bury the backbone into the core of protein fold. In the current study, we observed the effect of chemical chaperones from four different classes on the stability and functionality of aggregation prone protein zebrafish dihydrofolate reductase (zDHFR). We also used UV-visible and circular dichroism (CD) spectroscopy to explore the protecting action of chemical chaperones on the structure and activity of zDHFR in vitro and in vivo conditions.

The cytotoxic effects of dimethyl sulfoxide in mouse preimplantation embryos: a mechanistic study

Rationale: Dimethyl sulfoxide (DMSO) is commonly used as a solvent for water-insoluble substances, a vehicle for drug therapy, and a cryoprotectant for cultured cells. DMSO induced embryonic defects and its mechanism of action remains unclear. The rationale is based on the assumption that DMSO supplementation should induce long-term negative effects on both pre- and post-implantation embryo development.

Methods: DMSO induced oxidative stress, ER stress, autophagy, mitophagy, signaling responsible genes and proteins were determined by RT-qPCR, Western blotting, immunofluorescence, and confocal microscopy. DMSO induced mitochondrial dysfunction was measured by transmission electron microcopy and JC-1 assay. Apoptosis was estimated using TUNEL and comet assay. Post-implantation embryo developmental capability was estimated by implantation site and fetus numbers.

Results: Exposure to DMSO induced an early oxidative stress response within 0.5 to 2 h in 1-cell zygotes by disrupting the balance of pro- and anti-oxidants. Notably, DMSO-treated 2-cell embryos showed increased expression of unfolded protein response genes such as Hspa5, Hsp90b1, Ddit3, Atf4, and Xbp1. As a result, the development of many embryos is arrested at the 2-cell, 4-cell, or morula stages in a dose-dependent manner. Further, DMSO-induced endoplasmic reticulum stress increased mitochondrial Ca²⁺ levels, induced mitochondrial depolarization/dysfunction, and induced apoptotic cell death via the JNK/ATF2-dependent pathway. Consequently, treatment with DMSO increased the expression of autophagy initiation-, phagophore elongation-, and autophagosome formation-related genes, as well as localization of PINK1/Parkin, which are the main mediators of mitophagy, in mitochondria. Interestingly, DMSO causes cytotoxic effects in preimplantation embryos by inducing extensive mitophagy and autophagy. Especially, DMSO treatment decreased the inner cell mass and trophectoderm cell numbers as well as mRNA expression of B3gnt5 and Wnt3a in developed blastocysts, which decreased the implantation and developmental rates of full-term offspring after being transferred into pseudopregnant mice.

Conclusion: These results provide a significant contribution to finding effective protective agents to combat DMSO mediated reproductive toxicity for application in human embryos in the near future.

Wine Phenolic Compounds: Antimicrobial Properties against Yeasts, Lactic Acid and Acetic Acid Bacteria

Microorganisms play an important role in the conversion of grape juice into wine. Yeasts belonging the genus Saccharomyces are mainly responsible for the production of ethanol, but members of other genera are known as producers of off-flavors, e.g., volatile phenols. Lactic acid and acetic acid bacteria also occur regularly in must and wine. They are mostly undesirable due to their capacity to produce wine-spoiling compounds (acetic acid, biogenic amines, N-heterocycles, diacetyl, etc.). In conventional winemaking, additions of sulfite or lysozyme are used to inhibit growth of spoilage microorganisms. However, there is increasing concern about the health risks connected with these enological additives and high interest in finding alternatives. Phenols are naturally occurring compounds in grapes and wine and are well known for their antimicrobial and health-promoting activities. In this study, we tested a selection of phenolic compounds for their effect on growth and viability of wine-associated yeasts and bacteria. Our investigations confirmed the antimicrobial activities of ferulic acid and resveratrol described in previous studies. In addition, we found syringaldehyde highly efficient against wine-spoiling bacteria at concentrations of 250–1000 µg/mL. The promising bioactive activities of this aromatic aldehyde and its potential for winemaking deserves further research.

Evaluation of cell wall damage by dimethyl sulfoxide in Candida species

Studies dealing with the response of microorganisms to oxidative stress require the dissolution of oxidant agents in an appropriate solvent. A commonly used medium is dimethyl sulfoxide, which has been considered as an innocuous polar solvent. However, we have observed significant differences between control, untreated cells and those receiving increasing amounts of the oxidant and hence increasing amounts of DMSO, to the maximum allowed of 1%. Here we show that, while this solvent does not influence yeast cell viability, it does affect expression of cell wall proteins as well as catalase activity. Therefore, its use in future studies of oxidative stress as an innocuous solvent should be reconsidered.

Chromatin Regulation by the NuA4 Acetyltransferase Complex Is Mediated by Essential Interactions Between Enhancer of Polycomb (Epl1) and Esa1

Enzymes that modify and remodel chromatin act in broadly conserved macromolecular complexes. One key modification is the dynamic acetylation of histones and other chromatin proteins by opposing activities of acetyltransferase and deacetylase complexes. Among acetyltransferases, the NuA4 complex containing Tip60 or its Saccharomyces cerevisiae ortholog Esa1 is of particular significance because of its roles in crucial genomic processes including DNA damage repair and transcription. The catalytic subunit Esa1 is essential, as are five noncatalytic NuA4 subunits. We found that of the noncatalytic subunits, deletion of Enhancer of polycomb (Epl1), but not the others, can be bypassed by loss of a major deacetylase complex, a property shared by Esa1 Noncatalytic complex subunits can be critical for complex assembly, stability, genomic targeting, substrate specificity, and regulation. Understanding the essential role of Epl1 has been previously limited, a limitation now overcome by the discovery of its bypass suppression. Here, we present a comprehensive in vivo study of Epl1 using the powerful tool of suppression combined with transcriptional and mutational analyses. Our results highlight functional parallels between Epl1 and Esa1 and further illustrate that the structural role of Epl1 is important for promotion of Esa1 activity. This conclusion is strengthened by our dissection of Epl1 domains required in vivo for interaction with specific NuA4 subunits, histone acetylation, and chromatin targeting. These results provide new insights for the conserved, essential nature of Epl1 and its homologs, such as EPC1/2 in humans, which is frequently altered in cancers.

Proteome targets of ubiquitin-like samp1ylation are associated with sulfur metabolism and oxidative stress in Haloferax volcanii

Small archeal modifier proteins (SAMPs) are related to ubiquitin in tertiary structure and in their isopeptide linkage to substrate proteins. SAMPs also function in sulfur mobilization to form biomolecules such as molybdopterin and thiolated tRNA. While SAMP1 is essential for anaerobic growth and covalently attached to lysine residues of its molybdopterin synthase partner MoaE (K240 and K247), the full diversity of proteins modified by samp1ylation is not known. Here, we expand the knowledge of proteins isopeptide linked to SAMP1. LC-MS/MS analysis of -Gly-Gly signatures derived from SAMP1 S85R conjugates cleaved with trypsin was used to detect sites of sampylation (23 lysine residues) that mapped to 11 target proteins. Many of the identified target proteins were associated with sulfur metabolism and oxidative stress including MoaE, SAMP-activating E1 enzyme (UbaA), methionine sulfoxide reductase homologs (MsrA and MsrB), and the Fe-S assembly protein SufB. Several proteins were found to have multiple sites of samp1ylation, and the isopeptide linkage at SAMP3 lysines (K18, K55, and K62) revealed hetero-SAMP chain topologies. Follow-up affinity purification of selected protein targets (UbaA and MoaE) confirmed the LC-MS/MS results. 3D homology modeling suggested sampy1ylation is autoregulatory in inhibiting the activity of its protein partners (UbaA and MoaE), while occurring on the surface of some protein targets, such as SufB and MsrA/B. Overall, we provide evidence that SAMP1 is a ubiquitin-like protein modifier that is relatively specific in tagging its protein partners as well as proteins associated with oxidative stress response.

Dimethyl sulphoxide modifies growth and senescence and induces the non-revertible petite phenotype in yeast

Dimethyl sulphoxide is extensively used in chemical, pharmaceutical and biomedical applications, but its specific biological actions remain largely elusive. The aim of this study was to comprehensively explore the effects of dimethyl sulphoxide on eukaryotic growth and senescence by using the budding yeast Saccharomyces cerevisiae as a reliable model organism. Rather than focusing on single cells or on either the replicative or the chronological lifespan approach, well-established microbiological procedures were integrated to monitor a combination of physiological parameters. Cell proliferation, survival, reproductive competence and morphology were recorded at various time points during incubation of asynchronous yeast populations with increasing concentrations of dimethyl sulphoxide. The findings demonstrated a dose-dependent inhibitory effect of the compound on yeast proliferation, survival and reproduction. In parallel, dimethyl sulphoxide induced the acquisition of the non-revertible petite phenotype and promoted morphological alterations that characterize senescence, driving the yeast populations towards the reproductive incompetent state. These findings point to the need for the investigation of the complex cellular and/or molecular mechanisms underlying the actions of dimethyl sulphoxide in eukaryotic cells and for the evaluation of their exploitation potential.

Cepharanthine alleviates liver injury in a rodent model of limb ischemia-reperfusion

OBJECTIVES

Limb ischemia-reperfusion (I/R) causes remote organ injury (e.g., liver injury). Oxidation and inflammation are crucial mechanisms. We investigated the effects of cepharanthine, a potent antioxidative and anti-inflammatory drug, on alleviating liver injury induced by limb I/R.

METHODS

Twenty-four adult male Sprague-Dawley rats were randomized to receive sham operation (Sham), Sham plus cepharanthine, I/R, or I/R plus cepharanthine and designated as the Sham, Sham+Cep, I/R, or I/R+Cep group, respectively (n = 6 in each group). I/R was induced by applying rubber band tourniquets high around each hind limb for 3 hours followed by reperfusion for 24 hours.

RESULTS

The plasma levels of aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of the Sham and Sham+Cep groups were low, and the levels of AST and ALT of the I/R group were significantly higher than those of the Sham group (both p<0.001). By contrast, the AST and ALT of the I/R+Cep group were significantly lower than those of the I/R group (both p<0.001). The hepatic levels of nitric oxide (NO), malondialdehyde (MDA), macrophage inflammatory protein 2 (MIP-2), interleukin-6 (IL-6), and cyclooxygenase-2 (COX-2)/prostaglandin E2 (PGE2) of the Sham and Sham+Cep groups were also low. As expected, the NO, MDA, MIP-2, IL-6, and COX-2/PGE2 of the I/R group were significantly higher than those of the Sham group (all p<0.001). By contrast, the NO, MDA, MIP-2, IL-6, and COX-2/PGE2 of the I/R+Cep group were significantly lower than those of the I/R group (all p<0.05).

CONCLUSION

Cepharanthine alleviates liver injury in a rodent model of limb I/R. The mechanisms may involve reducing oxidation and inflammation.