RESUMO
Alzheimer's disease (AD) is a progressive neurodegenerative disorder marked by the accumulation of amyloid-beta plaques and hyperphosphorylated tau proteins, leading to cognitive decline and neuronal death. However, despite extensive research, there are still no effective treatments for this condition. In this study, a series of chloride-substituted Ramalin derivatives is synthesized to optimize their antioxidant, anti-inflammatory, and their potential to target key pathological features of Alzheimer's disease. The effect of the chloride position on these properties is investigated, specifically examining the potential of these derivatives to inhibit tau aggregation and beta-site amyloid precursor protein cleaving enzyme 1 (BACE-1) activity. Our findings demonstrate that several derivatives, particularly RA-3Cl, RA-4Cl, RA-26Cl, RA-34Cl, and RA-35Cl, significantly inhibit tau aggregation with inhibition rates of approximately 50%. For BACE-1 inhibition, Ramalin and RA-4Cl also significantly decrease BACE-1 expression in N2a cells by 40% and 38%, respectively, while RA-23Cl and RA-24Cl showed inhibition rates of 30% and 35% in SH-SY5Y cells. These results suggest that chloride-substituted Ramalin derivatives possess promising multifunctional properties for AD treatment, warranting further investigation and optimization for clinical applications.
Assuntos
Doença de Alzheimer , Secretases da Proteína Precursora do Amiloide , Ácido Aspártico Endopeptidases , Proteínas tau , Doença de Alzheimer/tratamento farmacológico , Doença de Alzheimer/metabolismo , Humanos , Proteínas tau/metabolismo , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/metabolismo , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/metabolismo , Cloretos/química , Antioxidantes/farmacologia , Antioxidantes/síntese química , Antioxidantes/química , Agregados Proteicos/efeitos dos fármacos , Linhagem Celular Tumoral , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/químicaRESUMO
When cells are exposed to freezing temperatures, high concentrations of cryoprotective agents (CPA) prevent ice crystal formation, thus enhancing cell survival. However, high concentrations of CPAs can also cause cell toxicity. Exopolysaccharides (EPSs) from polar marine environments exhibit lower toxicity and display effects similar to traditional CPA. In this study, we sought to address these issues by i) selecting strains that produce EPS with novel cryoprotective activity, and ii) optimizing culture conditions for EPS production. Sixty-six bacteria producing mucous substances were isolated from the Ross Sea (Antarctic Ocean) using solid marine agar plates. Among them, Pseudoalteromonas sp. RosPo-2 was ultimately selected based on the rheological properties of the produced EPS (p-CY02). Cryoprotective activity experiments demonstrated that p-CY02 exhibited significantly cryoprotective activity at a concentration of 0.8% (w/v) on mammalian cells (HaCaT). This activity was further improved when combined with various concentrations of dimethyl sulfoxide (DMSO) compared to using DMSO alone. Moreover, the survival rate of HaCaT cells treated with 5% (v/v) DMSO and 0.8% (w/v) p-CY02 was measured at 87.9 ± 2.8% after freezing treatment. This suggests that p-CY02 may be developed as a more effective, less toxic, and novel non-permeating CPA. To enhance the production of EPS with cryoprotective activity, Response Surface Methodology (RSM) was implemented, resulting in a 1.64-fold increase in production of EPS with cryoprotective activity.
Assuntos
Sobrevivência Celular , Crioprotetores , Meios de Cultura , Polissacarídeos Bacterianos , Pseudoalteromonas , Pseudoalteromonas/metabolismo , Polissacarídeos Bacterianos/farmacologia , Polissacarídeos Bacterianos/biossíntese , Polissacarídeos Bacterianos/metabolismo , Crioprotetores/farmacologia , Crioprotetores/metabolismo , Meios de Cultura/química , Regiões Antárticas , Humanos , Sobrevivência Celular/efeitos dos fármacos , Dimetil Sulfóxido/farmacologia , Dimetil Sulfóxido/metabolismo , Células HaCaT , Linhagem Celular , Água do Mar/microbiologiaRESUMO
Sulfurtransferases transfer of sulfur atoms from thiols to acceptors like cyanide. They are categorized as thiosulfate sulfurtransferases (TSTs) and 3-mercaptopyruvate sulfurtransferases (MSTs). TSTs transfer sulfur from thiosulfate to cyanide, producing thiocyanate. MSTs transfer sulfur from 3-mercaptopyruvate to cyanide, yielding pyruvate and thiocyanate. The present study aimed to isolate and characterize the sulfurtransferase FrST from Frondihabitans sp. PAMC28461 using biochemical and structural analyses. FrST exists as a dimer and can be classified as a TST rather than an MST according to sequence-based clustering and enzyme activity. Furthermore, the discovery of activity over a wide temperature range and the broad substrate specificity exhibited by FrST suggest promising prospects for its utilization in industrial applications, such as the detoxification of cyanide.
Assuntos
Cisteína/análogos & derivados , Tiocianatos , Tiossulfatos , Sulfurtransferases/química , Tiossulfato Sulfurtransferase , Ácido Pirúvico , Cianetos , EnxofreRESUMO
Cryopreservation of human red blood cells (RBCs) is vital for regenerative medicine and organ transplantation, but current cryoprotectants (CPAs) like glycerol and hydroxyethyl starch (HES) have limitations. Glycerol requires post-thaw washing due to cell membrane penetration, while HES causes high viscosity. To address these issues, we explored exopolysaccharides (EPS) from Antarctic Pseudoalteromonas sp. strain CY01 as a non-penetrating CPA for RBC cryopreservation. The EPS, p-CY01, consisted mainly of repeating (1-4) glucose and (1-6) galactose linkages with a molecular mass of 1.1 × 107 Da. Through mild acid hydrolysis, we obtained low molecular weight p-CY01 (p-CY01 LM) with a molecular weight of 2.7 × 105 Da, offering reduced viscosity, improved solubility, and cryoprotective properties. Notably, combining low concentrations of penetrating CPAs (>1% glycerol and dimethyl sulfoxide) with 2.5% (w/v) p-CY01 LM demonstrated significant cryoprotective effects. These findings highlight the potential of p-CY01 LM as a highly effective CPA for human RBC cryopreservation, replacing HES and glycerol and enabling the long-term storage of biological materials.
RESUMO
Polar microorganisms produce biologically active compounds that enable them to survive in harsh environments. These compounds have potential biomedical applications. The green microalga Chlamydomonas latifrons KNF0041, isolated from Arctic sea ice, has been found to produce polyunsaturated fatty acids (PUFAs), including omega-3 and omega-6, which have antioxidant properties. To improve the biomass production of strain KNF0041, statistical methods such as the Plackett-Burman design, Box-Behnken design, and response surface methodology (RSM) were utilized for medium optimization. The optimized medium was designed with increased potassium phosphate content and reduced acetic acid (AcOH) content. The use of the optimized medium resulted in an increase in the cell number as biomass of strain KNF0041 by 34.18% and the omega-3 and omega-6 fatty acid (FA) content by 10.04% and 58.29%, respectively, compared to that in normal TAP medium, which is known as the growth medium for Chlamydomonas culture. In this study, Chlamydomonas latifrons was discovered for the first time in the polar region and identified using morphology and molecular phylogenetic analyses, the secondary structures of the internal transcribed spacers, and optimized culture conditions. The results of this study provide an efficient method for the application of polar microalgae for the production of bioactive compounds.
Assuntos
Chlamydomonas , Ácidos Graxos Ômega-3 , Microalgas , Biomassa , Camada de Gelo , FilogeniaRESUMO
Ornithine carbamoyltransferases (OTCs) are involved in the arginine deiminase (ADI) pathway and in arginine biosynthesis. Two OTCs in a pair are named catalytic OTC (cOTC) and anabolic OTC (aOTC). The cOTC is responsible for catalyzing the third step of the ADI pathway to catabolize citrulline into carbamoyl phosphate (CP), as well as ornithine, and displays CP cooperativity. In contrast, aOTC catalyzes the biosynthesis of citrulline from CP and ornithine in vivo and is thus involved in arginine biosynthesis. Structural and biochemical analyses were employed to investigate the CP cooperativity and unidirectional function of two sequentially similar OTCs (32.4% identity) named Ps_cOTC and Ps_aOTC from Psychrobacter sp. PAMC 21119. Comparison of the trimeric structure of these two OTCs indicated that the 80s loop of Ps_cOTC has a unique conformation that may influence cooperativity by connecting the CP binding site and the center of the trimer. The corresponding 80s loop region of in Ps_aOTC was neither close to the CP binding site nor connected to the trimer center. In addition, results from the thermal shift assay indicate that each OTC prefers the substrate for the unidirectional process. The active site exhibited a blocked binding site for CP in the Ps_cOTC structure, whereas residues at the active site in Ps_aOTC established a binding site to facilitate CP binding. Our data provide novel insights into the unidirectional catalysis of OTCs and cooperativity, which are distinguishable features of two metabolically specialized proteins.
Assuntos
Carbamoil-Fosfato , Psychrobacter , Sequência de Aminoácidos , Arginina , Sítios de Ligação , Carbamoil-Fosfato/química , Catálise , Citrulina , Cicloexanonas , Ornitina/química , Ornitina Carbamoiltransferase/metabolismo , Psychrobacter/metabolismoRESUMO
Stereocalpin B, a new cyclic depsipeptide (1), and a new dibenzofuran derivative (3), were isolated from the Antarctic lichen, Ramalina terebrata (Ramalinaceae), along with a known cyclic depsipeptide (2). The structures of new compounds were characterized by comprehensive spectrometric analyses; high-resolution fast atom bombardment mass spectrometry (HR-FABMS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS). Stereocalpin B (1) existed in a rotameric equilibrium, which was confirmed using nuclear Overhauser effect spectroscopy (NOESY)/exchange spectroscopy (EXSY) spectrum. Absolute configurations of the amino acid units in 1 were assigned using the advanced Marfey's method and subsequent NOESY analysis of the 5-hydroxy-2,4-dimethyl-3-oxo-decanoic acid residue confirmed the complete stereochemistry of 1. Compounds 1-3 exhibited moderate antimicrobial activities against E. coli, with the IC50 values ranging from 18-30 µg/mL. Compound 2 exhibited cell growth inhibition against HCT116 cell lines, with the IC50 value of 20 ± 1.20 µM, and compounds 1 and 2 also showed potent anti-inflammatory activities against lipopolysaccharide (LPS)-induced RAW264.7 macrophages with the IC50 values ranging from 5-7 µM.
RESUMO
Ice-binding proteins (IBPs) are well-characterized proteins responsible for the cold-adaptation mechanisms. Despite extensive structural and biological investigation of IBPs and antifreeze proteins, only a few studies have considered the relationship between protein stabilization and thermal hysteresis (TH) activity as well as the implication of hyperactivity. Here, we investigated the important role of the head capping region in stabilization and the hyper-TH activity of FfIBP using molecular dynamics simulation. Data comparison revealed that residues on the ice-binding site of the hyperactive FfIBP are immobilized, which could be correlated with TH activity. Further comparison analysis indicated the disulfide bond in the head region is mainly involved in protein stabilization and is crucial for hyper-TH activity. This finding could also be generalized to known hyperactive IBPs. Furthermore, in mimicking the physiological conditions, bacteria with membrane-anchored FfIBP formed brine pockets in a TH activity-dependent manner. Cells with a higher number of TH-active IBPs showed an increased number of brine pockets, which may be beneficial for short- and long-term survival in cold environments by reducing the salt concentration. The newly identified conditions for hyper-TH activity and their implications on bacterial survival provide insights into novel mechanistic aspects of cold adaptation in polar microorganisms.
Assuntos
Proteínas de Transporte , Gelo , Proteínas Anticongelantes/química , Bactérias/metabolismo , Sítios de Ligação , Proteínas de Transporte/metabolismo , Gelo/análiseRESUMO
The pathogenesis of Alzheimer's disease (AD) is still unclear, and presently there is no cure for the disease that can be used for its treatment or to stop its progression. Here, we investigated the therapeutic potential of ramalin (isolated from the Antarctic lichen, Ramalina terebrata), which exhibits various physiological activities, in AD. Specifically, derivatives were synthesized based on the structure of ramalin, which has a strong antioxidant effect, BACE-1 inhibition activity, and anti-inflammatory effects. Therefore, ramalin and its derivatives exhibit activity against multiple targets associated with AD and can serve as potential therapeutic agents for the disease.
Assuntos
Doença de Alzheimer/tratamento farmacológico , Anti-Inflamatórios/uso terapêutico , Antioxidantes/uso terapêutico , Glutamatos/uso terapêutico , Doença de Alzheimer/metabolismo , Secretases da Proteína Precursora do Amiloide/antagonistas & inibidores , Secretases da Proteína Precursora do Amiloide/metabolismo , Anti-Inflamatórios/síntese química , Anti-Inflamatórios/química , Antioxidantes/síntese química , Antioxidantes/química , Ácido Aspártico Endopeptidases/antagonistas & inibidores , Ácido Aspártico Endopeptidases/metabolismo , Compostos de Bifenilo/antagonistas & inibidores , Glutamatos/síntese química , Glutamatos/química , Humanos , Estrutura Molecular , Picratos/antagonistas & inibidoresRESUMO
Two undescribed rearranged cadinane-type sesquiterpenoids (1-2), named sinulaketol A-B, together with one new chlorinated steroid (3), one new gorgosterol (4), one known sesquiterpene (5), one known dibromoditerpene (6) and two known polyhydroxylated steroids (7-8) were isolated from the soft coral Sinularia brassica. The structures of these compounds were established by extensive spectroscopic analysis, including HRESIMS, 1D, and 2D NMR spectroscopy. Their absolute configurations were also determined by the ECD calculations and DP4+ probability analysis. Antileishmanial activity of compounds 1-8 was evaluated in vitro against the amastigote forms of Leishmania donovani, in which compounds 3, 6, and 7 inhibited the growth of L. donovani by 58.7, 74.3, 54.7%, respectively, at a concentration of 50 µM. Antimicrobial effect of the isolated compounds were also evaluated against Candida albicans, Staphylococcus aureus, and Escherichia coli. Compound 6, a brominated diterpene, exhibited antimicrobial effect against S. aureus.
Assuntos
Antozoários , Antibacterianos/química , Antiprotozoários/química , Sesquiterpenos/química , Esteroides/química , Animais , Antibacterianos/farmacologia , Antiprotozoários/farmacologia , Candida albicans/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Leishmania donovani/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Sesquiterpenos/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Esteroides/farmacologia , Relação Estrutura-AtividadeRESUMO
We report the first mitochondrial genome of the Antarctic microalga Micractinium simplicissimum KSF0127. The circular mitochondrial genome was 67,923 bp in length and contained 45 protein-coding genes, one ribosomal RNA gene, and 60 transfer RNA genes. The phylogenetic tree was constructed with eight previously reported mitogenome sequences and showed the phylogenetic position of M. simplicissimum KSF0127 within the Chlorellaceae family.
RESUMO
Umbilicaria antarctica (UA) is a member of the family Umbilicariaceae. To the best of our knowledge, no studies on its anti-inflammatory effects have been reported yet. In the present study, we examined its ability to suppress inflammatory responses and the molecular mechanisms underlying these abilities using lipopolysaccharide- (LPS-) stimulated RAW 264.7 cells and a zebrafish model of inflammation. We investigated the effects of UA on the production of nitric oxide (NO) and prostaglandin E2 (PGE2) in LPS-stimulated RAW 264.7 cells. To explore the anti-inflammatory mechanisms of UA, we measured the mRNA and protein expression of proinflammatory mediators in LPS-stimulated RAW 264.7 cells using quantitative RT-PCR and western blot analyses, respectively. UA significantly inhibited the production of NO, PGE2, interleukin- (IL-) 6, and tumor necrosis factor- (TNF-) α in the LPS-stimulated RAW 264.7 cells. It also suppressed the mRNA and protein expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and nuclear factor- (NF-) κB activation in LPS-stimulated RAW 264.7 cells and tail pin-cutting-induced zebrafish model. Collectively, these findings indicate that UA significantly inhibits LPS-stimulated inflammatory responses. These effects were considered to be strongly associated with the suppression of NF-κB activation. Overall, our results demonstrate that UA extract exerts strong anti-inflammatory activities in in vitro and in vivo models and suggest that UA may be an effective novel therapeutic agent for the treatment of inflammatory diseases.
Assuntos
Anti-Inflamatórios/farmacologia , Ascomicetos/química , Misturas Complexas/farmacologia , Líquens/química , Lipopolissacarídeos/toxicidade , Animais , Anti-Inflamatórios/química , Misturas Complexas/química , Modelos Animais de Doenças , Inflamação/induzido quimicamente , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Inflamação/patologia , Metanol/química , Camundongos , Células RAW 264.7 , Peixe-ZebraRESUMO
The aim of the present study was to determine the anti-inflammatory effect of an extracts isolated from the lichen. Amandinea sp. was collected from the Antarctic and extracted with methanol. The basic screening of the anti-inflammatory property of the extracts was done using the NO assay. The extracts showed very little cytotoxicity, and reduced NO production in LPS-stimulated RAW 264.7 cells in a dose-dependent manner. Furthermore, the extracts inhibited LPS-induced release of pro-inflammatory cytokines such as interleukin-6 (IL-6), and tumor necrosis factor-α(TNF-α), and inflammatory mediators inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). The extracts also reduced the cytosolic p-IκB-α level and the level of the nuclear factor p65. We examined the anti-inflammatory effects of the extracts using zebrafish in vivo. The extracts reduced the amount of reactive oxygen species (ROS) in LPS-induced zebrafish larvae and inhibited the mRNA expression of inflammatory cytokines and mediators in a tail-cutting induced model. These results are similar to those obtained in vitro with RAW 264.7 cells. Collectively, the data suggest that the extracts may contain one of more compounds with anti-inflammatory effects. Further studies are required to identify the candidate compound/s and to understand the mechanism of action of the extract.
Assuntos
Anti-Inflamatórios/farmacologia , Ascomicetos/química , Doenças dos Peixes/tratamento farmacológico , Inflamação/veterinária , Líquens/química , Peixe-Zebra/imunologia , Animais , Inflamação/tratamento farmacológico , Lipopolissacarídeos/farmacologia , Camundongos , Células RAW 264.7RESUMO
BACKGROUND: Biofuels, generated using microalgae as sustainable energy, have received a lot of attention. Microalgae can be cultivated at low cost with CO2 and solar energy without competition from edible crops. Psychrophilic microalgae can be a suitable feedstock to produce biofuels without the environmental constraints of low temperatures, because they can grow below 10 °C. However, there is a lack of efficient strategies using psychrophilic microalgae to produce biodiesel and bioethanol. Therefore, the current study aimed to optimize the production of biodiesel and bioethanol from Arctic Chlamydomonas sp. KNM0029C at low temperatures. RESULTS: After incubation in a 20-L photobioreactor, fatty acid methyl ester (FAME) was extracted using modified FAME extraction methods, producing a maximum yield of 0.16-g FAME/g KNM0029C. Residual biomass was pretreated for bioethanol production, and the yields from different methods were compared. The highest bioethanol yield (0.22-g/g residual biomass) was obtained by pretreatment with enzyme (amyloglucosidase) after sonication. Approximately 300-mg biofuel was obtained, including 156-mg FAME biodiesel and 144-mg bioethanol per g dried cells, representing the highest recorded yield from psychrophilic microalgae. CONCLUSIONS: This is the first to attempt at utilizing biomass from psychrophilic Arctic microalga Chlamydomonas sp. KNM0029C for the co-production of bioethanol and biodiesel, and it yielded the highest values among reported studies using psychrophilic organisms. These results can be used as a source for the efficient biofuel production using polar microalgae.
RESUMO
A lipid-producing microalga, Chlamydomonas sp. KNF0008, collected from the Arctic was capable of growing at temperatures ranging from 4 to 20 °C, and the highest cell density was measured at 15 °C and 100 µmol photons m-2 s-1 light intensity under continuous shaking and external aeration. KNF0008 showed the elevated accumulation of lipid bodies under nitrogen-deficient conditions, rather than under nitrogen-sufficient conditions. Fatty acid production of KNF0008 was 4.2-fold (104 mg L-1) higher than that of C. reinhardtii CC-125 at 15 °C in Bold's Basal Medium. The dominant fatty acids were C16:0, C16:4, C18:1, and C18:3, and unsaturated fatty acids (65.69%) were higher than saturated fatty acids (13.65%) at 15 °C. These results suggested that Arctic Chlamydomonas sp. KNF0008 could possibly be utilized for production of biodiesel during periods of cold weather because of its psychrophilic characteristics.
Assuntos
Chlamydomonas/metabolismo , Lipídeos/biossíntese , Microalgas/metabolismo , Regiões Árticas , Biocombustíveis , Chlamydomonas/classificação , Chlamydomonas/genética , Temperatura Baixa , Ácidos Graxos/biossíntese , Ácidos Graxos/química , Cinética , Luz , Lipídeos/química , Microalgas/classificação , Microalgas/genética , Nitrogênio/metabolismo , FilogeniaRESUMO
The first total syntheses of the natural products lobaric acid (1) and its derivatives isolated from the Antarctic lichen Stereocaulon alpinum are reported in this study. Lobarin (3), with a pseudodepsidone structure, was synthesized first in 11 steps by utilizing an Ullmann aryl ether coupling reaction, and lobaric acid was synthesized in an additional three steps by a seven-membered lactonization reaction. Various derivatives were also obtained from the prepared lobaric acid, and the synthetic compounds exhibited significant PTP1B inhibitory activities.
Assuntos
Ascomicetos/química , Lactonas/química , Líquens/química , Éteres Fenílicos/química , Salicilatos/química , Regiões Antárticas , Depsídeos/química , Proteína Tirosina Fosfatase não Receptora Tipo 1/antagonistas & inibidoresRESUMO
Lobaric acid and lobarstin, secondary metabolites derived from the antarctic lichen Stereocaulon alpnum, exert various biological activities, including antitumor, anti-proliferation, anti-inflammation, and antioxidant activities. However, the underlying mechanisms of these effects have not yet been elucidated in human cervix adenocarcinoma and human colon carcinoma. In the present study, we evaluated the anticancer effects of lobaric acid and lobarstin on human cervix adenocarcinoma HeLa cells and colon carcinoma HCT116 cells. We show that the proliferation of Hela and HCT116 cells treated with lobaric acid and lobarstin significantly decreased in a dose- and time-dependent manner. Using flow cytometry analysis, we observed that the treatment with these compounds resulted in significant apoptosis in both cell lines, following cell cycle perturbation and arrest in G2/M phase. Furthermore, using immunoblot analysis, we investigated the expression of cell cycle and apoptosis-related marker genes and found a significant downregulation of the apoptosis regulator B-cell lymphoma 2 (Bcl-2) and upregulation of the cleaved form of the poly (ADP-ribose) polymerase (PARP), a DNA repair and apoptosis regulator. These results suggest that lobaric acid and lobarstin could significantly inhibit cell proliferation through cell cycle arrest and induction of apoptosis via the mitochondrial apoptotic pathway in cervix adenocarcinoma and colon carcinoma cells. Taken together, our data suggests that lobaric acid and lobarstin might be novel agents for clinical treatment of cervix adenocarcinoma and colon carcinoma.
Assuntos
Antineoplásicos/farmacologia , Benzofuranos/farmacologia , Neoplasias do Colo/metabolismo , Hidroxibenzoatos/farmacologia , Lactonas/farmacologia , Líquens/química , Salicilatos/farmacologia , Neoplasias do Colo do Útero/metabolismo , Antineoplásicos/isolamento & purificação , Benzofuranos/química , Benzofuranos/isolamento & purificação , Pontos de Checagem do Ciclo Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Sobrevivência Celular/efeitos dos fármacos , Neoplasias do Colo/tratamento farmacológico , Depsídeos/química , Depsídeos/isolamento & purificação , Depsídeos/farmacologia , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Células HCT116 , Células HeLa , Humanos , Hidroxibenzoatos/química , Hidroxibenzoatos/isolamento & purificação , Lactonas/química , Lactonas/isolamento & purificação , Estrutura Molecular , Poli(ADP-Ribose) Polimerases/metabolismo , Proteínas Proto-Oncogênicas c-bcl-2/metabolismo , Salicilatos/química , Salicilatos/isolamento & purificação , Neoplasias do Colo do Útero/tratamento farmacológicoRESUMO
Enzymes isolated from organisms found in cold habitats generally exhibit higher catalytic activity at low temperatures than their mesophilic homologs and are therefore known as cold-active enzymes. Cold-active proteases are very useful in a variety of biotechnological applications, particularly as active ingredients in laundry and dishwashing detergents, where they provide strong protein-degrading activity in cold water. We identified a cold-active protease (Pro21717) from a psychrophilic bacterium, Pseudoalteromonas arctica PAMC 21717, and determined the crystal structure of its catalytic domain (CD) at a resolution of 1.4 Å. The Pro21717-CD structure shows a conserved subtilisin-like fold with a typical catalytic triad (Asp185, His244, and Ser425) and contains four calcium ions and three disulfide bonds. Interestingly, we observed an unexpected electron density at the substrate-binding site from a co-purified peptide. Although the sequence of this peptide is unknown, analysis of the peptide-complexed structure nonetheless provides some indication of the substrate recognition and binding mode of Pro21717. Moreover, various parameters, including a wide substrate pocket size, an abundant active-site loop content, and a flexible structure provide potential explanations for the cold-adapted properties of Pro21717. In conclusion, this is first structural characterization of a cold-adapted subtilisin-like protease, and these findings provide a structural and functional basis for industrial applications of Pro21717 as a cold-active laundry or dishwashing detergent enzyme.
Assuntos
Temperatura Baixa , Detergentes/química , Peptídeo Hidrolases/química , Pseudoalteromonas/enzimologia , Sequência de Aminoácidos , Domínio Catalítico , Clonagem Molecular , Cristalografia por Raios X , Concentração de Íons de Hidrogênio , Lavanderia , Peptídeo Hidrolases/genética , Peptídeo Hidrolases/metabolismo , Conformação Proteica , Proteólise , Homologia de Sequência de Aminoácidos , Especificidade por SubstratoRESUMO
BACKGROUND: Cancer is a leading cause of human death around the world and occurs through the highly complex coordination of multiple cellular pathways. Recent studies have revealed that microalgal extracts exhibit considerable pharmaceutical activities, including those against various cancer cells. Thus, microalgae are promising candidates as novel cancer therapeutic drugs. In this study, we evaluated the biological functions of the ethanolic extract of the Antarctic freshwater microalga, Bo tryidiopsidaceae sp., such as its antioxidant, anti-proliferative, apoptotic and anti-invasive properties. METHODS: To estimate antioxidant capacity of ethanol extract of Bo tryidiopsidaceae sp. (ETBO), free radical 2,2'-azino-bis (3-ethylbenzthiazoline-6-sulphonic acid) (ABTS) and 1,1-diphenyl-2-picrylhydrazyl (DPPH) assays were used. The anti-proliferative activity of ETBO was assessed in several cancer cell lines (A375, Hs578T and HeLa) and non-tumorigenic keratinocyte cells (HaCaT), using MTT assay. In addition, Annexin V binding was performed to detect ETBO-induced apoptotic cells, and the expression levels of apoptosis-regulating proteins, caspase-3, p53, and Bcl-2, were determined by western blot. Boyden chamber assays were used to determine anti-migratory and anti-invasive properties of ETBO. RESULTS: ETBO exhibited antioxidant activity and concentration-dependent anticancer activities, such as anti-proliferation and pro-apoptotic activities against cancer cells. Furthermore, the expression of the apoptosis-inducing proteins, p53 and caspase-3, significantly increased in response to ETBO, whereas the expression of the anti-apoptotic protein, Bcl-2, decreased. These data imply that ETBO induces apoptosis by caspase activation through the modulation of pro-apoptotic and anti-apoptotic gene, p53 and Bcl-2, respectively. In addition, ETBO significantly inhibited migration and invasion of cervical cancer cells in a concentration-dependent manner. CONCLUSION: In this study, ETBO exhibited considerable anticancer activities, such as inhibition of proliferation, invasion, and migration, as well as induction of apoptosis. These data suggest that ETBO is a promising therapeutic agent in cancer therapy and drug discovery.
Assuntos
Antineoplásicos/farmacologia , Microalgas/química , Extratos Vegetais/farmacologia , Estramenópilas/química , Regiões Antárticas , Antineoplásicos/química , Apoptose/efeitos dos fármacos , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Água Doce , Células HeLa , Humanos , Extratos Vegetais/químicaRESUMO
Colorectal cancer is a leading cause of death worldwide and occurs through the highly complex coordination of multiple cellular pathways, resulting in carcinogenesis. Recent studies have increasingly revealed that constituents of lichen extracts exhibit potent pharmaceutical activities, including anticancer activity against various cancer cells, making them promising candidates for new anticancer therapeutic drugs. The main objective of this study was to evaluate the anticancer capacities of ramalin, a secondary metabolite from the Antarctic lichen Ramalina terebrata, in the human colorectal cancer cell line HCT116. In this study, ramalin displayed concentration-dependent anticancer activity against HCT116 cells, significantly suppressing proliferation and inducing apoptosis. Furthermore, ramalin induced cell cycle arrest in the gap 2/mitosis (G2/M) phase through the modulation of hallmark genes involved in the G2/M phase transition, such as tumour protein p53 (TP53), cyclin-dependent kinase inhibitor 1A (CDKN1A), cyclin-dependent kinase 1 (CDK1) and cyclin B1 (CCNB1). At both the transcriptional and translational level, ramalin caused a gradual increase in the expression of TP53 and its downstream gene CDKN1A, while decreasing the expression of CDK1 and CCNB1 in a concentration-dependent manner. In addition, ramalin significantly inhibited the migration and invasion of colorectal cancer cells in a concentration-dependent manner. Taken together, these data suggest that ramalin may be a therapeutic candidate for the targeted therapy of colorectal cancer.