Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 53
Filtrar
Mais filtros

Base de dados
Tipo de documento
Intervalo de ano de publicação
1.
Food Microbiol ; 120: 104484, 2024 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-38431329

RESUMO

Trichothecium roseum is a typical necrotrophic fungal pathogen that not only bring about postharvest disease, but contribute to trichothecenes contamination in fruit and vegetables. Phospholipase D (PLD), as an important membrane lipid degrading enzyme, can produce phosphatidic acid (PA) by hydrolyzing phosphatidylcholine (PC) and phosphatidylinositol (PI). PA can promote the production of reactive oxygen species (ROS) by activating the activity of NADPH oxidase (NOX), thereby increasing the pathogenicity to fruit. However, the ROS mediated by TrPLD3 how to influence T. roseum infection to fruit by modulating phosphatidic acid metabolism, which has not been reported. In this study, the knockout mutant and complement strain of TrPLD3 were constructed through homologous recombination, TrPLD3 was tested for its effect on the colony growth and pathogenicity of T. roseum. The experimental results showed that the knockout of TrPLD3 inhibited the colony growth of T. roseum, altered the mycelial morphology, completely inhibited the sporulation, and reduced the accumulation of T-2 toxin. Moreover, the knockout of TrPLD3 significantly decreased pathogenicity of T. roseum on apple fruit. Compared to inoculated apple fruit with the wide type (WT), the production of ROS in apple infected with ΔTrPLD3 was slowed down, the relative expression and enzymatic activity of NOX, and PA content decreased, and the enzymatic activity and gene expression of superoxide dismutase (SOD) increased. In addition, PLD, lipoxygenase (LOX) and lipase activities were considerably decreased in apple fruit infected with ΔTrPLD3, the changes of membrane lipid components were slowed down, the decrease of unsaturated fatty acid content was alleviated, and the accumulation of saturated fatty acid content was reduced, thereby maintaining the cell membrane integrity of the inoculated apple fruit. We speculated that the decreased PA accumulation in ΔTrPLD3-inoculated apple fruit further weakened the interaction between PA and NOX on fruit, resulting in the reduction of ROS accumulation of fruits, which decreased the damage to the cell membrane and maintained the cell membrane integrity, thus reducing the pathogenicity to apple. Therefore, TrPLD3-mediated ROS plays a critical regulatory role in reducing the pathogenicity of T. roseum on apple fruit by influencing phosphatidic acid metabolism.


Assuntos
Frutas , Hypocreales , Malus , Frutas/microbiologia , Malus/microbiologia , Espécies Reativas de Oxigênio/metabolismo , Membrana Celular/metabolismo , Lipídeos de Membrana/metabolismo
2.
Int J Mol Sci ; 24(4)2023 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-36835350

RESUMO

A serious problem currently facing the field of wound healing is bacterial infection, especially Staphylococcus aureus (S. aureus) infection. Although the application of antibiotics has achieved good effects, their irregular use has resulted in the emergence of drug-resistant strains. It is thus the purpose of this study to analyze whether the naturally extracted phenolic compound, juglone, can inhibit S. aureus in wound infection. The results show that the minimum inhibitory concentration (MIC) of juglone against S. aureus was 1000 µg/mL. Juglone inhibited the growth of S. aureus by inhibiting membrane integrity and causing protein leakage. At sub-inhibitory concentrations, juglone inhibited biofilm formation, the expression of α-hemolysin, the hemolytic activity, and the production of proteases and lipases of S. aureus. When applied to infected wounds in Kunming mice, juglone (50 µL juglone with a concentration of 1000 µg/mL) significantly inhibited the number of S. aureus and had a significant inhibitory effect on the expression of inflammatory mediators (TNF-α, IL-6 and IL-1ß). Moreover, the juglone-treated group promoted wound healing. At the same time, in animal toxicity experiments, juglone had no obvious toxic effects on the main tissues and organs of mice, indicating that juglone has good biocompatibility and has the potential to be used in the treatment of wounds infected with S. aureus.


Assuntos
Antibacterianos , Naftoquinonas , Infecções Estafilocócicas , Infecção dos Ferimentos , Animais , Camundongos , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Testes de Sensibilidade Microbiana , Infecções Estafilocócicas/tratamento farmacológico , Staphylococcus aureus/efeitos dos fármacos , Infecção dos Ferimentos/tratamento farmacológico , Infecção dos Ferimentos/microbiologia , Naftoquinonas/farmacologia , Naftoquinonas/uso terapêutico
3.
Int J Mol Sci ; 24(10)2023 May 17.
Artigo em Inglês | MEDLINE | ID: mdl-37240243

RESUMO

Plant diseases caused by phytopathogenic fungi are a serious threat in the process of crop production and cause large economic losses to global agriculture. To obtain high-antifungal-activity compounds with novel action mechanisms, a series of 4-substituted mandelic acid derivatives containing a 1,3,4-oxadiazole moiety were designed and synthesized. In vitro bioassay results revealed that some compounds exhibited excellent activity against the tested fungi. Among them, the EC50 values of E13 against Gibberella saubinetii (G. saubinetii), E6 against Verticillium dahlia (V. dahlia), and E18 against Sclerotinia sclerotiorum (S. sclerotiorum) were 20.4, 12.7, and 8.0 mg/L, respectively, which were highly superior to that of the commercialized fungicide mandipropamid. The morphological studies of G. saubinetii with a fluorescence microscope (FM) and scanning electron microscope (SEM) indicated that E13 broke the surface of the hyphae and destroyed cell membrane integrity with increased concentration, thereby inhibiting fungal reproduction. Further cytoplasmic content leakage determination results showed a dramatic increase of the nucleic acid and protein concentrations in mycelia with E13 treatment, which also indicated that the title compound E13 could destroy cell membrane integrity and affect the growth of fungi. These results provide important information for further study of the mechanism of action of mandelic acid derivatives and their structural derivatization.


Assuntos
Antifúngicos , Fungicidas Industriais , Antifúngicos/química , Fungicidas Industriais/farmacologia , Ácidos Mandélicos/farmacologia , Oxidiazóis , Relação Estrutura-Atividade
4.
Bull Environ Contam Toxicol ; 110(4): 67, 2023 Mar 19.
Artigo em Inglês | MEDLINE | ID: mdl-36934155

RESUMO

The present study aims to signify the role of Pyxine cocoes (Sw.) Nyl. (P. cocoes) as cadmium (Cd) biomonitor in atmosphere. This was achieved by quantifying the amount of Cd accumulated in transplanted P. cocoes, when stimulated with known concentrations of Cd (5µM, 50µM, 100µM, 150µM and 200µM) at increasing intervals of time up-to 40 days. All the five concentrations exhibited increasing trend of accumulation with time. As depicted by Pearson's Correlation (at p < 0.001), anti-oxidative enzymes (superoxide dismutase r= -0.812, ascorbate peroxidase r= -0.802, catalase r= -0.757) and electrical conductivity (r = 0.693) were the most efficient parameters to depict increased Cd presence in atmosphere. In the current study, accumulation of Cd by transplanted lichen has been first time analyzed by biosorption kinetics. The uptake of Cd by P. cocoes followed pseudo-second-order kinetics (range of R22 value was 0.969-0.998). The marker parameters in combination with the ability to accrue Cd fortifies P. cocoes's role as a biomonitor.


Assuntos
Ascomicetos , Líquens , Cádmio , Líquens/metabolismo , Catalase/metabolismo , Cinética , Superóxido Dismutase/metabolismo
5.
J Basic Microbiol ; 62(8): 930-936, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35689329

RESUMO

The YJL218W open reading frame may be involved in peroxisomal biogenesis. However, whether it mediates salt tolerance is unclear. We found that after knockdown of YJL218W in Saccharomyces cerevisiae (S. cerevisiae), its salt tolerance was reduced and cell death was increased. Transcriptome sequencing and analysis further revealed that YJL218W knockdown mediated significant changes in the expression of 1432 messenger RNA (mRNAs), of which 603 were upregulated. KEGG enrichment analysis and polymerase chain reaction (PCR) assay indicated that YJL218W mediated the regulation of peroxisome-related genes. Therefore, YJL218W may regulate salt stress in S. cerevisiae by regulating peroxisome assembly.


Assuntos
Proteínas de Saccharomyces cerevisiae , Saccharomyces cerevisiae , Peroxissomos/genética , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Proteínas de Saccharomyces cerevisiae/metabolismo , Tolerância ao Sal/genética
6.
Molecules ; 27(18)2022 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-36144641

RESUMO

The ubiquitous presence of nanoplastics (NPs) in natural ecosystems is a serious concern, as NPs are believed to threaten every life form on Earth. Micro- and nanoplastics enter living systems through multiple channels. Cell membranes function as the first barrier of entry to NPs, thus playing an important biological role. However, in-depth studies on the interactions of NPs with cell membranes have not been performed, and effective theoretical models of the underlying molecular details and physicochemical behaviors are lacking. In the present study, we investigated the uptake of polyvinyl chloride (PVC) nanoparticles by Arabidopsis thaliana root cells, which leads to cell membrane leakage and damage to membrane integrity. We performed all-atom molecular dynamics simulations to determine the effects of PVC NPs on the properties of the multicomponent lipid bilayer. These simulations revealed that PVCs easily permeate into model lipid membranes, resulting in significant changes to the membrane, including reduced density and changes in fluidity and membrane thickness. Our exploration of the interaction mechanisms between NPs and the cell membrane provided valuable insights into the effects of NPs on membrane structure and integrity.


Assuntos
Arabidopsis , Nanopartículas , Arabidopsis/metabolismo , Membrana Celular/metabolismo , Ecossistema , Bicamadas Lipídicas/química , Microplásticos , Simulação de Dinâmica Molecular , Nanopartículas/química , Cloreto de Polivinila/análise
7.
Microbiology (Reading) ; 167(6)2021 06.
Artigo em Inglês | MEDLINE | ID: mdl-34170816

RESUMO

Marine plastic pollution is a growing concern worldwide and has the potential to impact marine life via leaching of chemicals, with zinc (Zn), a common plastic additive, observed at particularly high levels in plastic leachates in previous studies. At this time, however, little is known regarding how elevated Zn affects key groups of marine primary producers. Marine cyanobacterial genera Prochlorococcus and Synechococcus are considered to be some of the most abundant oxygenic phototrophs on earth, and together contribute significantly to oceanic primary productivity. Here we set out to investigate how two Prochlorococcus (MIT9312 and NATL2A) and two Synechococcus (CC9311 and WH8102) strains, representative of diverse ecological niches, respond to exposure to high Zn concentrations. The two genera showed differences in the timing and degree of growth and physiological responses to elevated Zn levels, with Prochlorococcus strains showing declines in their growth rate and photophysiology following exposure to 27 µg l-1 Zn, while Synechococcus CC9311 and WH8102 growth rates declined significantly on exposure to 52 and 152 µg l-1 Zn, respectively. Differences were also observed in each strain's capacity to maintain cell wall integrity on exposure to different levels of Zn. Our results indicate that excess Zn has the potential to pose a challenge to some marine picocyanobacteria and highlights the need to better understand how different marine Prochlorococcus and Synechococcus strains may respond to increasing concentrations of Zn in some marine regions.


Assuntos
Prochlorococcus/efeitos dos fármacos , Synechococcus/efeitos dos fármacos , Poluentes Químicos da Água/toxicidade , Zinco/toxicidade , Prochlorococcus/crescimento & desenvolvimento , Água do Mar/análise , Água do Mar/microbiologia , Synechococcus/crescimento & desenvolvimento , Poluentes Químicos da Água/análise , Zinco/análise
8.
Ecotoxicol Environ Saf ; 207: 111264, 2021 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-32911184

RESUMO

This study investigated the effect of the herbicide metolachlor (MET) on the redox homeostasis of the freshwater green alga Pseudokirchneriella subcapitata. At low MET concentrations (≤40 µg L-1), no effects on algal cells were detected. The exposure of P. subcapitata to 45-235 µg L-1 MET induced a significant increase of reactive oxygen species (ROS). The intracellular levels of ROS were particularly increased at high (115 and 235 µg L-1) but environmentally relevant MET concentrations. The exposure of algal cells to 115 and 235 µg L-1 MET originated a decrease in the levels of antioxidants molecules (reduced glutathione and carotenoids) as well as a reduction of the activity of scavenging enzymes (superoxide dismutase and catalase). These results suggest that antioxidant (non-enzymatic and enzymatic) defenses were affected by the excess of MET. As consequence of this imbalance (ROS overproduction and decline of the antioxidant system), ROS inflicted oxidative injury with lipid peroxidation and damage of cell membrane integrity. The results provide further insights about the toxic modes of action of MET on a non-target organism and emphasize the relevance of toxicological studies in the assessment of the impact of herbicides in freshwater environments.


Assuntos
Acetamidas/toxicidade , Clorofíceas/efeitos dos fármacos , Herbicidas/toxicidade , Poluentes Químicos da Água/toxicidade , Antioxidantes/metabolismo , Catalase/metabolismo , Clorofíceas/fisiologia , Água Doce , Glutationa/metabolismo , Homeostase/efeitos dos fármacos , Peroxidação de Lipídeos/efeitos dos fármacos , Oxirredução , Estresse Oxidativo/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Superóxido Dismutase/metabolismo
9.
Andrologia ; 53(2): e13907, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33263218

RESUMO

In many cell types, the potential of reactive oxygen species to induce death processes has been largely demonstrated. Studies in spermatozoa have associated the imbalance of reactive oxygen species and phosphatidylserine externalisation as an apoptosis marker. However, the lack of consensus about time effect in the joint expression of these and other death markers has made it difficult to understand the set of mechanisms influenced beyond the concentration effect of reactive oxygen species to stimulate cell death. Here, the plasma membrane permeability and integrity, phosphatidylserine externalisation and mitochondrial membrane potential were jointly evaluated as death markers in human spermatozoa stimulated with H2 O2 . The results showed a profound and sustained effect of dissipation in the mitochondrial membrane potential and an increased phosphatidylserine externalisation in human spermatozoa exposed to 3 mmol-1 of H2 O2 at 30 min. This was followed by an increased membrane permeability after 45 min. The last observed event was the loss of cell membrane integrity at 60 min. In conclusion, mitochondria are rapidly affected in human spermatozoa exposed to reactive oxygen species, with the barely detectable mitochondrial membrane potential coexisting with the high phosphatidylserine externalisation in cells with normal membrane permeability.


Assuntos
Mitocôndrias , Espermatozoides , Morte Celular , Membrana Celular/metabolismo , Humanos , Masculino , Potencial da Membrana Mitocondrial , Mitocôndrias/metabolismo , Espécies Reativas de Oxigênio/metabolismo
10.
J Food Sci Technol ; 58(5): 1655-1662, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33897004

RESUMO

Button mushrooms (Agaricus bisporus) were put under stimulated storage and transportation environments with different amounts of phase-change materials (PCM). Results showed that the addition of PCM effectively maintained a cooler environment and delayed a rise in temperature. And the addition of PCM, especially in a ratio 1:2 PCM:mushroom, had a significant effect on delaying the increase in cell membrane permeability, malondialdehyde and H2O2 levels, and also delayed superoxide dismutase and catalase activity. These results suggest that PCM may be candidate in postharvest mushroom during storage and transportation.

11.
Microb Pathog ; 142: 104056, 2020 Feb 11.
Artigo em Inglês | MEDLINE | ID: mdl-32058023

RESUMO

Luteolin (LUT) is a naturally occurring compound found in a various of plants. Few recent studies have reported LUT antimicrobial activities against bacterial pathogens, however, the fundamental LUT mediated antimicrobial mechanism has never been elucidated. This study aimed to investigate the antimicrobial activities of LUT and its mode of action against Staphylococcus aureus and Listeria monocytogenes, either as planktonic cells or as biofilms. Here, minimum inhibitory concentration (MIC), and minimum bactericidal concentration (MBC) of LUT against S. aureus and L. monocytogenes were determined using the broth microdilution method, and the antimicrobial mode of LUT was elucidated by evaluating the variations in both cell membrane integrity and cell morphology. Moreover, the biofilm inhibition was measured by crystal violet staining assay, while its qualitative imaging was achieved by confocal laser scanning microscope and field emission scanning electron microscope. MIC and MBC values of LUT against S. aureus were 16-32 and 32-64 µg/mL, and 32-64 and 64-128 µg/mL for L. monocytogenes. LUT destroyed the cell membrane integrity, as evidenced by a significant increase in the number of non-viable cells, and well-defined variations in cell morphology. Moreover, LUT presented robust inhibitory effects on the biofilm formation, enhanced antibiotics diffusion within biofilms and killed efficiently mono- and dual-species biofilm cells. Overall, LUT demonstrates potent antimicrobial properties on planktonic and biofilm cells, and the biofilm formation, and thus has the potential use as a natural food preservative in foods.

12.
J Appl Microbiol ; 129(2): 278-286, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32097516

RESUMO

AIMS: The aim of the study was to investigate the antifungal effects of a quorum sensing-molecule, 2-phenylethanol, against the food spoilage moulds Penicillium expansum and Penicillium nordicum. METHODS AND RESULTS: Conidial germination of the tested Penicillium spp. (three strains in total) were inhibited by treatments with 2-phenylethanol in a concentration-dependent manner. Germinated conidia was significantly reduced from 4·4-16·7% at 7·5 mmol l-1 and completely inhibited at 15 mmol l-1 2-phenylethanol. Integrity of conidial cell membranes was unaffected by 2-phenylethanol resulting in reversible inhibition pattern of germination. In contrast, membrane permeability of actively growing hyphae was severely compromised, showing 63·5 - 75·7% membrane damage upon treatment with 15 mmol l-1 2-phenylethanol. The overall inhibitory effect of 2-phenylethanol on colony development and growth of P. expansum and P. nordicum was additionally confirmed. CONCLUSIONS: 2-phenylethanol inhibits conidial germination and growth of P. expansum and P. nordicum in a nonlethal, reversible and concentration-dependent manner. SIGNIFICANCE AND IMPACT OF THE STUDY: The study indicates that 2-phenylethanol can find potential application as an antifungal agent for biological control of moulds in the food industry.


Assuntos
Antifúngicos/farmacologia , Penicillium/efeitos dos fármacos , Álcool Feniletílico/farmacologia , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Hifas/efeitos dos fármacos , Penicillium/crescimento & desenvolvimento , Percepção de Quorum , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento
13.
Biofouling ; 36(1): 56-72, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31997658

RESUMO

The effects of two prominent copper oxide nanoparticles (CuO-NP and Cu2O-NP), with the oxidation state of Cu++ (cupric) and Cu+ (cuprous), on Candida albicans were evaluated. CuO-NP and Cu2O-NP were synthesized and characterized by XRD, FESEM, HR-TEM and Zeta potential. At sub-MIC (50 µg ml-1), both cupric and cuprous oxide NPs prevented yeast-to-hyphae switching and wrinkling behaviour in C. albicans. The mechanism for the antifungal action of the two NPs differed; CuO-NP significantly elicited reactive oxygen species, whereas membrane damage was more pronounced with Cu2O-NP. Real time PCR analysis revealed that CuO-NP suppressed the morphological switching of yeast-to-hyphae by down-regulating cph1, hst7 and ras1 and by up-regulation of the negative regulator tup1. In comparison, Cu2O-NP resulted in down-regulation of ras1 and up-regulation of the negative regulators nrg1 and tup1. Between the two NPs, CuO exhibited increased antifungal activity due to its stable oxidation state (Cu++) and its smaller dimensions compared with Cu2O-NP.


Assuntos
Antifúngicos/farmacologia , Candida albicans/efeitos dos fármacos , Cobre/farmacologia , Hifas/efeitos dos fármacos , Nanopartículas Metálicas/química , Candida albicans/crescimento & desenvolvimento , Candida albicans/metabolismo , Membrana Celular/efeitos dos fármacos , Hifas/crescimento & desenvolvimento , Hifas/metabolismo , Testes de Sensibilidade Microbiana , Espécies Reativas de Oxigênio/metabolismo
14.
Molecules ; 25(5)2020 Feb 28.
Artigo em Inglês | MEDLINE | ID: mdl-32121062

RESUMO

Herein we report the synthesis of two novel series of 1,3-thiazole derivatives having a lipophilic C4-substituent on account of the increasing need for novel and versatile antifungal drugs for the treatment of resistant Candida sp.-based infections. Following their structural characterization, the anti-Candida activity was evaluated in vitro while using the broth microdilution method. Three compounds exhibited lower Minimum Inhibitory Concentration (MIC) values when compared to fluconazole, being used as the reference antifungal drug. An in silico molecular docking study was subsequently carried out in order to gain more insight into the antifungal mechanism of action, while using lanosterol-C14α-demethylase as the target enzyme. Fluorescence microscopy was employed to further investigate the cellular target of the most promising molecule, with the obtained results confirming its damaging effect towards the fungal cell membrane integrity. Finally, the distribution and the pharmacological potential in vivo of the novel thiazole derivatives was investigated through the study of their binding interaction with bovine serum albumin, while using fluorescence spectroscopy.


Assuntos
Antifúngicos , Candida/crescimento & desenvolvimento , Soroalbumina Bovina/química , Tiazóis , Antifúngicos/síntese química , Antifúngicos/química , Antifúngicos/farmacologia , Avaliação Pré-Clínica de Medicamentos , Testes de Sensibilidade Microbiana , Relação Estrutura-Atividade , Tiazóis/síntese química , Tiazóis/química , Tiazóis/farmacologia
15.
Microb Pathog ; 107: 254-260, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28389345

RESUMO

Biofilm formation, low membrane permeability and efflux activity developed by Pseudomonas aeruginosa, play an important role in the mechanism of infection and antimicrobial resistance. In the present study we evaluate the antibacterial effect of Zingiber officinale against multi-drug resistant strain of P. aeruginosa. The study explores antibacterial efficacy and time-kill study concomitantly the effect of herbal extract on bacterial cell physiology with the use of flow cytometry and inhibition of biofilm formation. Z. officinale was found to inhibit the growth of P. aeruginosa, significantly. A major decline in the Colony Forming Units was observed with 3 log10 at 12 h of treatment. Also it is found to affect the membrane integrity of the pathogen, as 70.06 ± 2.009% cells were found to stain with Propidium iodide. In case of efflux activity 86.9 ± 2.08% cells were found in Ethidium bromide positive region. Biofilm formation inhibition ability was found in the range of 68.13 ± 4.11% to 84.86 ± 2.02%. Z.officinale is effective for killing Multi-Drug Resistant P. aeruginosa clinical isolate by affecting the cellular physiology and inhibiting the biofilm formation.


Assuntos
Antibacterianos/farmacologia , Citometria de Fluxo/métodos , Extratos Vegetais/farmacologia , Pseudomonas aeruginosa/efeitos dos fármacos , Pseudomonas aeruginosa/fisiologia , Zingiber officinale/química , Alcaloides/análise , Biofilmes/efeitos dos fármacos , Biofilmes/crescimento & desenvolvimento , Membrana Celular/efeitos dos fármacos , Contagem de Colônia Microbiana , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Flavonoides/análise , Peróxido de Hidrogênio/análise , Testes de Sensibilidade Microbiana , Viabilidade Microbiana/efeitos dos fármacos , Óxido Nítrico/análise , Propídio/metabolismo , Pseudomonas aeruginosa/crescimento & desenvolvimento , Rizoma/química , Taninos/análise , Fatores de Tempo
16.
Biotechnol Bioeng ; 114(6): 1241-1251, 2017 06.
Artigo em Inglês | MEDLINE | ID: mdl-28112406

RESUMO

Tools that allow cost-effective screening of the susceptibility of cell lines to operating conditions which may apply during full scale processing are central to the rapid development of robust processes for cell-based therapies. In this paper, an ultra scale-down (USD) device has been developed for the characterization of the response of a human cell line to membrane-based processing, using just a small quantity of cells that is often all that is available at the early discovery stage. The cell line used to develop the measurements was a clinically relevant human fibroblast cell line. The impact was evaluated by cell damage on completion of membrane processing as assessed by trypan blue exclusion and release of intracellular lactate dehydrogenase (LDH). Similar insight was gained from both methods and this allowed the extension of the use of the LDH measurements to examine cell damage as it occurs during processing by a combination of LDH appearance in the permeate and mass balancing of the overall operation. Transmission of LDH was investigated with time of operation and for the two disc speeds investigated (6,000 and 10,000 rpm or ϵmax ≈ 1.9 and 13.5 W mL-1 , respectively). As expected, increased energy dissipation rate led to increased transmission as well as significant increases in rate and extent of cell damage. The method developed can be used to test the impact of varying operating conditions and cell lines on cell damage and morphological changes. Biotechnol. Bioeng. 2017;114: 1241-1251. © 2017 The Authors. Biotechnology and Bioengineering Published by Wiley Periodicals, Inc.


Assuntos
Separação Celular/instrumentação , Centrifugação/instrumentação , Fibroblastos/citologia , Fibroblastos/fisiologia , Citometria de Fluxo/instrumentação , Ultrafiltração/instrumentação , Linhagem Celular , Separação Celular/métodos , Tamanho Celular , Sobrevivência Celular/fisiologia , Centrifugação/métodos , Desenho de Equipamento , Análise de Falha de Equipamento , Humanos , Membranas Artificiais , Reologia/instrumentação , Reologia/métodos , Resistência ao Cisalhamento/fisiologia , Estresse Mecânico , Ultrafiltração/métodos
17.
Biosci Biotechnol Biochem ; 80(12): 2325-2333, 2016 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-27684739

RESUMO

Glucolipids in Bacillus subtilis are synthesized by UgtP processively transferring glucose from UDP-glucose to diacylglycerol. Here we conclude that the abnormal morphology of a ugtP mutant is caused by lack of glucolipids, since the same morphology arises after abolition of glucolipid production by disruption of pgcA and gtaB, which are involved in UDP-glucose synthesis. Conversely, expression of a monoglucosyldiacylglycerol (MGlcDG) produced by 1,2-diacylglycerol 3-glucosyltransferase from Acholeplasma laidlawii (alMGS) almost completely suppressed the ugtP disruptant phenotype. Activation of extracytoplasmic function (ECF) sigmas (SigM, SigV, and SigX) in the ugtP mutant was decreased by alMGS expression, and was suppressed to low levels by MgSO4 addition. When alMGS and alDGS (A. laidlawii 1,2-diacylglycerol-3-glucose (1-2)-glucosyltransferase producing diglucosyldiacylglycerol (DGlcDG)) were simultaneously expressed, SigX activation was repressed to wild type level. These observations suggest that MGlcDG molecules are required for maintenance of B. subtilis cell shape and regulation of ECF sigmas, and DGlcDG regulates SigX activity.


Assuntos
Acholeplasma laidlawii/enzimologia , Bacillus subtilis/citologia , Bacillus subtilis/genética , Glucosiltransferases/genética , Mutação , Fator sigma/metabolismo , Acholeplasma laidlawii/genética , Bacillus subtilis/metabolismo , Expressão Gênica , Glucosiltransferases/metabolismo , Uridina Difosfato Glucose/metabolismo
18.
Aquaculture ; 463: 71-78, 2016 10 01.
Artigo em Inglês | MEDLINE | ID: mdl-27818535

RESUMO

Fluorescent dyes that binds irreversibly to cellular amines, come in several available emission spectra, and do not poses health concerns were used to evaluate membrane integrity in fish sperm cells. The objectives of the present study were to determine: (1) a working dye concentration for fish sperm samples, and (2) if the traditional propidium iodide/SYBR-14 staining combination was comparable with the amine reactive dye (ARD) methods at identifying cell populations with intact and compromised membranes after sperm activation, refrigerated storage, and exposure to cryoprotectant and surfactant. Zebrafish (Danio rerio) sperm were obtained by stripping, and pooled samples (in triplicate) were used in all tests. Six dilutions of the amine dye (ranging from 0.625 to 0.02 µL/mL) were evaluated, and compared with the traditional staining protocol. A concentration of 0.5 µL/mL ARD was selected to be used in subsequent assays. Sperm suspensions were activated with deionized water to simulate urine contamination. After 10 sec, osmolality was increased to stop activation, and the procedure was repeated in 10-sec intervals until the sperm remained activated for 120 consecutive sec; membrane integrity was analyzed at each time interval. For the storage assay, sperm suspensions were prepared in Hanks' balanced salt solution at 302 mOsm/kg osmolality (HBSS302), HBSS354 and HBSS402, and evaluated every 2 hr for 8 hr, and every 24 hr for 72 hr. Cryoprotectant toxicity was tested by diluting sperm suspensions in HBSS340 with methanol at 5, 10 and 15% final concentrations. Surfactant toxicity was tested by diluting sperm suspensions in HBSS354 with Triton X-100 at 0.2, 0.15 and 0.1 mM final concentrations. In each toxicity assay, membrane integrity was tested every 20 min for 80 min. The number of membrane-intact cells significantly decreased across time in all treatments (p < 0.05). Significant differences between staining protocols were observed after activation and after exposure to methanol at 10 and 15%, and to Triton X-100 (p < 0.05). The average difference, however, was minor (between 1 and 6% in average) in relation to the typical values used for decision making based on this assay. Results showed that this method has the potential to contribute greatly to the standardization of cryopreservation in aquatic species.

19.
FEBS J ; 291(14): 3191-3210, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38602252

RESUMO

Adaptation to hypoxia has attracted much public interest because of its clinical significance. However, hypoxic adaptation in the body is complicated and difficult to fully explore. To explore previously unknown conserved mechanisms and key proteins involved in hypoxic adaptation in different species, we first used a yeast model for mechanistic screening. Further multi-omics analyses in multiple species including yeast, zebrafish and mice revealed that glycerophospholipid metabolism was significantly involved in hypoxic adaptation with up-regulation of lysophospholipid acyltransferase (ALE1) in yeast, a key protein for the formation of dipalmitoyl phosphatidylcholine [DPPC (16:0/16:0)], which is a saturated phosphatidylcholine. Importantly, a mammalian homolog of ALE1, lysophosphatidylcholine acyltransferase 1 (LPCAT1), enhanced DPPC levels at the cell membrane and exhibited the same protective effect in mammalian cells under hypoxic conditions. DPPC supplementation effectively attenuated growth restriction, maintained cell membrane integrity and increased the expression of epidermal growth factor receptor under hypoxic conditions, but unsaturated phosphatidylcholine did not. In agreement with these findings, DPPC treatment could also repair hypoxic injury of intestinal mucosa in mice. Taken together, ALE1/LPCAT1-mediated DPPC formation, a key pathway of glycerophospholipid metabolism, is crucial for cell viability under hypoxic conditions. Moreover, we found that ALE1 was also involved in glycolysis to maintain sufficient survival conditions for yeast. The present study offers a novel approach to understanding lipid metabolism under hypoxia and provides new insights into treating hypoxia-related diseases.


Assuntos
1-Acilglicerofosfocolina O-Aciltransferase , Membrana Celular , Glicerofosfolipídeos , Animais , 1-Acilglicerofosfocolina O-Aciltransferase/metabolismo , 1-Acilglicerofosfocolina O-Aciltransferase/genética , Camundongos , Membrana Celular/metabolismo , Glicerofosfolipídeos/metabolismo , Saccharomyces cerevisiae/genética , Saccharomyces cerevisiae/metabolismo , Saccharomyces cerevisiae/crescimento & desenvolvimento , Humanos , Adaptação Fisiológica/genética , Hipóxia/metabolismo , Hipóxia/genética , Peixe-Zebra/metabolismo , Peixe-Zebra/genética , 1,2-Dipalmitoilfosfatidilcolina/metabolismo , 1,2-Dipalmitoilfosfatidilcolina/química , Mucosa Intestinal/metabolismo
20.
Pharmaceuticals (Basel) ; 17(1)2024 Jan 09.
Artigo em Inglês | MEDLINE | ID: mdl-38256922

RESUMO

The aim of this study was to investigate the antifungal activity of biochanin A (BCA) against planktonic growth and biofilms of six Candida species, including C. albicans, C. parapsilosis, C. glabrata, C. tropicalis, C. auris, and C. krusei. We applied various assays that determined (a) the antimicrobial effect on growth of Candida species, (b) the effect on formation of hyphae and biofilm, (c) the effect on the expression of genes related to hyphal growth and biofilm formation, (d) the influence on cell wall structure, and (e) the effect on cell membrane integrity and permeability. Moreover, disk diffusion tests were used to investigate the effect of a combination of BCA with fluconazole to assess their possible synergistic effect on drug-resistant C. albicans, C. glabrata, and C. auris. Our results showed that the BCA MIC50 values against Candida species ranged between 125 µg/mL and 500 µg/mL, and the MIC90 values were in a concentration range from 250 µg/mL to 1000 µg/mL. The treatment with BCA inhibited adhesion of cells, cell surface hydrophobicity (CSH), and biofilm formation and reduced hyphal growth in all the analyzed Candida species. Real-time qRT-PCR revealed that BCA down-regulated the expression of biofilm-specific genes in C. albicans. Furthermore, physical destruction of C. albicans cell membranes and cell walls as a result of the treatment with BCA was observed. The combination of BCA and fluconazole did not exert synergistic effects against fluconazole-resistant Candida.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA