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Pulsed vacuum drying (PVD) is a novel vacuum drying method that has demonstrated significant potential in improving energy efficiency and product quality in the drying of foods and agricultural products. The current work provides a comprehensive analysis of the latest advancements in PVD technology, including its historical development, fundamental principles, and mechanistic aspects. The impact of periodic pulsed pressure changes between vacuum and atmospheric pressure on heat and moisture transfer, as well as structural changes in foods at micro- and macro-scales, is thoroughly discussed. The article also highlights the influential drying parameters, the integration of novel auxiliary heaters, and the applications of PVD across various fruits, vegetables, and herbs. Furthermore, the review examines the current status and needs for mathematical modeling of PVD processes, identifying key challenges, research opportunities, and future trends for industrial application. The findings suggest that PVD not only enhances drying efficiency and reduces energy consumption but also preserves the nutritional value, color, and texture of dried products better than traditional methods. Future research should focus on optimizing process parameters and integrating advanced control systems to further improve the scalability and applicability of PVD technology in the food industry.
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Dessecação , Frutas , Verduras , Verduras/química , Vácuo , Frutas/química , Dessecação/métodos , Conservação de Alimentos/métodos , Manipulação de Alimentos/métodosRESUMO
Acquisition of new genes often results in the emergence of novel functions and is a key step in lineage-specific adaptation. As a group of sessile crustaceans, barnacles establish permanent attachment through initial cement secretion at the larval phase followed by continuous cement secretion in juveniles and adults. However, the origins and evolution of barnacle larval and adult cement proteins remain poorly understood. By performing microdissection of larval cement glands, transcriptome and shotgun proteomics and immunohistochemistry validation, we identified 30 larval and 27 adult cement proteins of the epibiotic turtle barnacle Chelonibia testudinaria, of which the majority are stage- and barnacle-specific. While only two proteins, SIPC and CP100K, were expressed in both larvae and adults, detection of protease inhibitors and the cross-linking enzyme lysyl oxidase paralogs in larvae and adult cement. Other barnacle-specific cement proteins such as CP100k and CP52k likely share a common origin dating back at least to the divergence of Rhizocephala and Thoracica. Different CP52k paralogues could be detected in larval and adult cement, suggesting stage-specific cement proteins may arise from duplication followed by changes in expression timing of the duplicates. Interestingly, the biochemical properties of larval- and adult-specific CP52k paralogues exhibited remarkable differences. We conclude that barnacle larval and adult cement systems evolved independently, and both emerged from co-option of existing genes and de novo formation, duplication and functional divergence of lineage-specific cement protein genes. Our findings provide important insights into the evolutionary mechanisms of bioadhesives in sessile marine invertebrates.
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Thoracica , Animais , Thoracica/genética , Thoracica/metabolismo , Proteínas/genética , Larva/genética , Larva/metabolismo , Transcriptoma/genéticaRESUMO
Two novel Gram-stain-negative, facultative anaerobic, non-flagellated, rod-shaped bacterial strains, designated MT13T and MT32, were isolated from sediment samples collected from the Mariana Trench at a depth of 8300 m. The two strains grew at -2-30 °C (optimum, 25 °C), at pH 5.5-10.0 (optimum, pH 7.5-8.0) and with 0-15â% (w/v) NaCl (optimum, 3-6â%). They did not reduce nitrate to nitrite nor hydrolyse Tweens 40 and 80, aesculin, casein, starch and DNA. The genomic G+C contents of draft genomes of strain MT13T and MT32 were 52.2 and 54.1 mâol%, respectively. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strains MT13T and MT32 were affiliated with the genus Halomonas, with the highest similarity to the type strain of Halomonas olivaria. The values of average nucleotide identity and in silico DNA-DNA hybridization between strain MT13T and MT32, and between strain MT13T and five closely related type strains of Halomonas species indicated that strains MT13T and MT32 belonged to the same species, but represented a novel species in the genus of Halomonas. The major cellular fatty acids of strains MT13T and MT32 were C16â:â0, summed feature 3(C16â:â1 ω7c/ω6c) and summed feature 8 (C18â:â1 ω7c/ω6c). Major polar lipids of strains MT13T and MT32 included phosphatidylglycerol, phosphatidylethanolamine and diphosphatidylglycerol. Ubiquinone-9 was the predominant respiratory quinone. Based on data from the present polyphasic study, strains MT13T and MT32 represent a novel species of the genus Halomonas, for which the name Halomonas profundi sp. nov. is proposed. The type strain is MT13T (=MCCC 1K06389T=KCTC 82923T).
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Sedimentos Geológicos/microbiologia , Halomonas , Filogenia , Água do Mar/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Halomonas/classificação , Halomonas/isolamento & purificação , Hibridização de Ácido Nucleico , Oceano Pacífico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/químicaRESUMO
Most marine copiotrophic bacteria can produce extracellular enzymes to degrade biopolymers into bio-available smaller solutes, while oligotrophic bacteria usually cannot. Bacterial extracellular enzymes and enzymatic products can be a common resource that could be utilized by both copiotrophs and oligotrophs; when present, oligotrophs may outcompete the enzyme-producing copiotrophs. However, copiotrophs and oligotrophs consistently coexist in the ocean. How they maintain coexistence has still not been experimentally studied. In this study, the interaction and coexistence of a copiotroph and an oligotroph, isolated from the same surface seawater sample and utilizing the same proteinaceous substrate, were experimentally investigated. The copiotroph could secrete extracellular proteases to degrade and then utilize the proteinaceous substrate. The oligotroph was unable to utilize the proteinaceous substrate by itself, but could grow by using the hydrolysate amino acids. The copiotroph outcompeted the oligotroph by adsorbing the amino acids quickly and having a higher growth rate in the rich medium. The oligotroph survived by adapting to low concentration of nutrients. The copiotroph and oligotroph were able to maintain long-term (up to 142 days) coexistence in the laboratory. This study indicates that differences in the utilization of different concentrations of nutrients can drive the coexistence of marine copiotrophs and oligotrophs.
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Bactérias/crescimento & desenvolvimento , Interações Microbianas , Água do Mar/microbiologia , Aminoácidos/análise , Aminoácidos/metabolismo , Bactérias/metabolismo , Meios de Cultura/química , Meios de Cultura/metabolismo , Nutrientes/análise , Nutrientes/metabolismo , Água do Mar/químicaRESUMO
In the version of this article originally published, the links and files for the Supplementary Information, including Supplementary Tables 1-5, Supplementary Figures 1-25, Supplementary Note, Supplementary Datasets 1-4 and the Life Sciences Reporting Summary, were missing in the HTML. The error has been corrected in the HTML version of this article.
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Nonribosomal peptide antibiotics, including polymyxin, vancomycin, and teixobactin, most of which contain D-amino acids, are highly effective against multidrug-resistant bacteria. However, overusing antibiotics while ignoring the risk of resistance arising has inexorably led to widespread emergence of resistant bacteria. Therefore, elucidation of the emerging mechanisms of resistance to nonribosomal peptide antibiotics is critical to their implementation. Here we describe a networking-associated genome-mining platform for linking biosynthetic building blocks to resistance components associated with biosynthetic gene clusters. By applying this approach to 5,585 complete bacterial genomes spanning the entire domain of bacteria, with subsequent chemical and enzymatic analyses, we demonstrate a mechanism of resistance toward nonribosomal peptide antibiotics that is based on hydrolytic cleavage by D-stereospecific peptidases. Our finding reveals both the widespread distribution and broad-spectrum resistance potential of D-stereospecific peptidases, providing a potential early indicator of antibiotic resistance to nonribosomal peptide antibiotics.
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Antibacterianos/química , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla/genética , Peptídeo Hidrolases/química , Peptídeos/química , Peptídeos Catiônicos Antimicrobianos , Bactérias/genética , Biologia Computacional , Farmacorresistência Bacteriana , Genoma Bacteriano , Hidrólise , Cinética , Família Multigênica , Mutação , Ligação Proteica , Ribossomos/química , EstereoisomerismoRESUMO
Doxorubicin (DOX) is an effective anti-tumor drug widely used in clinics. Hernandezine (HER), isolated from a Chinese medicinal herb, has a selective inhibitory effect on DOX multidrug resistance, making DOX more effective in treating cancer. The aim of this study was to investigate the effect of the interaction of HER and DOX on pharmacokinetics. Male Sparague-Dawley rats were randomly divided into three groups: a single DOX group, a single HER group, and a combination group. Plasma concentrations of DOX and HER were determined by the LC-MS/MS method at specified time points after administration, and the main pharmacokinetic parameters were estimated. The results showed that there were significant differences in the Cmax and AUC0-∞ of DOX in the single drug group and combined drug group, indicating that HER could improve the absorption of DOX. However, DOX in combination, in turn, reduced the free drug concentration of HER, possibly because DOX enhanced the HER drug-protein binding effect. The results could be used as clinical guidance for DOX and HER to avoid adverse reactions.
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Benzilisoquinolinas/farmacocinética , Cromatografia Líquida , Doxorrubicina/farmacocinética , Interações Medicamentosas , Medicamentos de Ervas Chinesas/farmacocinética , Espectrometria de Massas em Tandem , Limite de Detecção , Estrutura MolecularRESUMO
Colibactin is an as-yet-uncharacterized genotoxic secondary metabolite produced by human gut bacteria. Here we report the biosynthetic discovery of two new precolibactin molecules from Escherichia coli, including precolibactin-886, which uniquely incorporates the highly sought genotoxicity-associated aminomalonate building block into its unprecedented macrocyclic structure. This work provides new insights into the biosynthetic logic and mode of action of this colorectal-cancer-linked microbial chemical.
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Malonatos/metabolismo , Peptídeos/metabolismo , Policetídeos/metabolismo , Escherichia coli/metabolismo , Humanos , Malonatos/química , Conformação Molecular , Peptídeos/química , Policetídeos/químicaRESUMO
Glass sponge (Hexactinellida, Porifera) is a special lineage because of its unique tissue organization and skeleton material. Structure and physiology of glass sponge have been extensively studied. However, our knowledge of the glass sponge-associated microbial community and of the interaction with the host is rather limited. Here, we performed genomic studies on the microbial community in the glass sponge Lophophysema eversa in seamount. The microbial community was dominated by an ammonia-oxidizing archaeum (AOA), a nitrite-oxidizing bacterium (NOB) and a sulfur-oxidizing bacterium (SOB), all of which were autotrophs. Genomic analysis on the AOA, NOB and SOB in the sponge revealed specific functional features of sponge-associated microorganisms in comparison with the closely related free-living relatives, including chemotaxis, phage defence, vitamin biosynthesis and nutrient uptake among others, which are related to ecological functions. The three autotrophs play essential roles in the cycles of carbon, nitrogen and sulfur in the microenvironment inside the sponge body, and they are considered to play symbiotic roles in the host as scavengers of toxic ammonia, nitrite and sulfide. Our study extends knowledge regarding the metabolism and the evolution of chemolithotrophs inside the invertebrate body.
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Archaea/isolamento & purificação , Carbono/metabolismo , Gammaproteobacteria/isolamento & purificação , Nitrogênio/metabolismo , Poríferos/microbiologia , Enxofre/metabolismo , Amônia/metabolismo , Animais , Archaea/classificação , Archaea/genética , Processos Autotróficos/fisiologia , Gammaproteobacteria/classificação , Gammaproteobacteria/genética , Genoma Arqueal/genética , Genoma Bacteriano/genética , Genômica , Microbiota/genética , Oxirredução , Filogenia , SimbioseRESUMO
Adenosine (Ado) is an important cardioprotective agent. Since endogenous Ado levels are affected by the enzyme Ado deaminase (ADA), polymorphisms within the ADA gene may exert some effect on chronic heart failure (CHF). This study applied a case-control investigation to 300 northern Chinese Han CHF patients and 400 ethnicity-matched healthy controls in which nine single-nucleotide polymorphisms (SNPs) of ADA were genotyped and association analyses were performed. Odds ratios (ORs) with 95% confidence intervals (CI) were used to assess the association. Overall, rs452159 polymorphism in ADA gene was significantly associated with susceptibility to CHF under the dominant model (p = 0.013, OR = 1.537, 95% CI = 1.10-2.16), after adjustment for age, sex, and traditional cardiovascular risk factors. No difference in genotype distribution and allele frequency for the rs452159 according to the functional New York Heart Association class was found. Furthermore, the values of left ventricular ejection fraction, left-ventricle end-diastolic diameter or left-ventricle end-systolic diameter did not differ significantly among the different rs452159 genotype CHF patients. Although further studies with larger cohorts and other ethnicities are required to validate the conclusions, the findings of this study potentially provide novel insight into the pathogenesis of CHF.
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Adenosina Desaminase/genética , Insuficiência Cardíaca/genética , Polimorfismo de Nucleotídeo Único , Idoso , Estudos de Casos e Controles , China , Feminino , Humanos , Masculino , Pessoa de Meia-IdadeRESUMO
In the title complex, [ZnCl2(C10H9N5)2], the Zn(II) ion is coordinated by two N atoms from two 2-[(1H-1,2,4-triazol-1-yl)meth-yl]-1H-benzimidazole (tmb) ligands and by two chloride ligands in a slightly distorted tetra-hedral geometry. In the tmb ligands, the benzimidazole rings systems are essentially planar, with maximum deviations from the mean plane of 0.021â (3) and 0.030â (3)â Å, and form dihedral angles of 73.2â (2) and 83.5â (2)° with the triazole rings. In the crystal, N-Hâ¯N hydrogen bonds link complex mol-ecules into chains along [010]. In addition, weak C-Hâ¯Cl and C-Hâ¯N hydrogen bonds complete a three-dimensional network. Two weak intra-molecular C-Hâ¯Cl hydrogen bonds are also observed.
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In the current work, the effects of steam and boiling water blanching on the drying characteristics, water distribution, microstructure, and contents of bioactive substances of Gastrodia elata (G. elata) were explored. Results showed that the degree of steaming and blanching was related to the core temperature of G. elata. The steaming and blanching pretreatment increased the drying time of the samples by more than 50%. The low-field nuclear magnetic resonance (LF-NMR) of treated samples showed that the relaxation time corresponded to water molecule states (bound, immobilized, and free) and G. elata became shorter, which indicated a reduction in free moisture and increased resistance of water diffusion in the solid structure during drying. Hydrolysis of polysaccharides and gelatinization of starch granules was observed in the microstructure of treated samples, which was consistent with changes in water status and drying rates. Steaming and blanching increased gastrodin and crude polysaccharide contents and decreased p-hydroxybenzyl alcohol content. These findings will contribute to a better understanding of the effect of steaming and blanching on the drying behavior and quality attributes of G. elata.
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OBJECTIVE: To describe the clinical features and surgical outcomes in a series of patients with perforating injuries and foreign bodies located at the exit wound in posterior global wall. METHODS: Retrospective case series of 17 eyes of 17 patients were included in the study, each patient who received treatments between January 2006 and December 2010 had perforating injuries with foreign bodies located at posterior global wall. The exit wounds of perforating injuries were in the area of optic disc and macula in 8 eyes. Seventeen eyes had vitreous hemorrhage, 11 eyes had traumatic cataract, 8 eyes had retinal detachment and one eye had endophthalmitis. According to different therapeutic regimen, cases were divided into two groups. Group A (7 cases) underwent vitrectomy combined with extraction of foreign body as an emergency operation. Group B (10 cases) underwent extraction of foreign body as an emergency operation and secondary vitrectomy were performed 1 - 2 weeks later. The mean follow-up time was 18 months (ranged from 9 - 47 months). The functional and anatomical results were compared between Group A and B. Fisher's exact test were used to analyze the data. RESULTS: The foreign bodies were extracted in 17 cases. Poor final best corrected visual acuity (BCVA) (worse than or equal to 0.1) was presented in all 8 cases with the exit wound being in the area of optic disc and macula, but only in 4 of 9 cases with the exit wound located in other sites, the difference between these two groups was statistically significant (P = 0.029). At final follow-up, vision was improved in 5 cases from Group A and 7 cases from Group B (P = 1.000); BCVA were better than or equal to 0.1 in 4 cases from Group A and 3 cases from Group B (P = 0.350) the differences were statistically nonsignificant. Intraoperative leakage at the exit wound occurred in 4 cases from Group A and one from Group B, the difference was statistically significant (P = 0.015). Intraoperative retinal detachment and postoperative silicone oil leakage occurred in 2 cases from Group A and none from Group B (P = 0.154). Postoperative retinal detachment occurred in 1 case from Group A and 3 cases from Group B (P = 0.603). Silicone oil-dependent eye occurred in 1 case from Group A and 2 cases from Group B (P = 1.000); the differences were statistically nonsignificant. CONCLUSIONS: The visual prognosis is worse in cases with the exit wound being in the area of optic disc and macula. Both therapeutic regimens were effective, but each has their pros and cons. Appropriate therapeutic regimen should be selected in term of situations. To avoid leakage at the exit wound in vitrectomy, we recommend therapeutic regimen B be selected first.
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Corpos Estranhos no Olho/cirurgia , Ferimentos Oculares Penetrantes/cirurgia , Adulto , Humanos , Masculino , Pessoa de Meia-Idade , Prognóstico , Estudos Retrospectivos , VitrectomiaRESUMO
Dimethylsulfide (DMS) and dimethylsulfoxide (DMSO) are widespread in marine environment, and are important participants in the global sulfur cycle. Microbiol oxidation of DMS to DMSO represents a major sink of DMS in marine surface waters. The SAR11 clade and the marine Roseobacter clade (MRC) are the most abundant heterotrophic bacteria in the ocean surface seawater. It has been reported that trimethylamine monooxygenase (Tmm, EC 1.14.13.148) from both MRC and SAR11 bacteria likely oxidizes DMS to generate DMSO. However, the structural basis of DMS oxidation has not been explained. Here, we characterized a Tmm homolog from the SAR11 bacterium Pelagibacter sp. HTCC7211 (Tmm7211). Tmm7211 exhibits DMS oxidation activity in vitro. We further solved the crystal structures of Tmm7211 and Tmm7211 soaked with DMS, and proposed the catalytic mechanism of Tmm7211, which comprises a reductive half-reaction and an oxidative half-reaction. FAD and NADPH molecules are essential for the catalysis of Tmm7211. In the reductive half-reaction, FAD is reduced by NADPH. In the oxidative half-reaction, the reduced FAD reacts with O2 to form the C4a-(hydro)peroxyflavin. The binding of DMS may repel the nicotinamide ring of NADP+, and make NADP+ generate a conformational change, shutting off the substrate entrance and exposing the active C4a-(hydro)peroxyflavin to DMS to complete the oxidation of DMS. The proposed catalytic mechanism of Tmm7211 may be widely adopted by MRC and SAR11 bacteria. This study provides important insight into the conversion of DMS into DMSO in marine bacteria, leading to a better understanding of the global sulfur cycle.
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OBJECTIVE: To investigate the modification function of visual experience onto synapses by recording developmental changes of spontaneous excitatory postsynaptic currents (sEPSC) in layer 2 and 3 pyramidal neurons of rat visual cortex, and to observe the spontaneous synaptic activities during the earlier postnatal period. METHODS: This was an experimental study. By combining infrared differential interference contrast (IR-DIC) technique and a CCD-camera system with visual patch clamp whole-cell recording technique, spontaneous EPSCs of P2 approximately 7, P8 approximately 14, P15 approximately 21 and P22 approximately 28 groups were observed and analyzed. The neurons were stained by adding 0.3% Lucifer yellow to the pipette solution simultaneously. RESULTS: The amplitude of sEPSC was enhanced when aging (F = 20.69, P < 0.01). The sEPSC frequency increased with age (F = 87.46, P < 0.01). There was no significant difference between P2 approximately 7 groups and P8 approximately 14 groups (P > 0.05). The electrophysiology and dendrite of neuron became mature whilst development. CONCLUSIONS: During the early postnatal days neurons were relatively immature, and became mature during development. Visual experience played an important role in this process. In spite of most synapses were taken silent at early postnatal days, and NMDA receptor-mediated function was revealed exclusively, these results suggested that early AMPA receptor-mediated functional activities existed in layer 2 and 3 pyramidal neurons. Synapses were not completely silent, but had early spontaneous activities.
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Potenciais Pós-Sinápticos Excitadores/fisiologia , Neurônios/fisiologia , Células Piramidais/metabolismo , Córtex Visual/crescimento & desenvolvimento , Córtex Visual/fisiologia , Animais , Técnicas de Patch-Clamp , Células Piramidais/fisiologia , Ratos , Ratos Wistar , Receptores de AMPA/fisiologiaRESUMO
Colibactin is an assumed human gut bacterial genotoxin, whose biosynthesis is linked to the clb genomic island that has a widespread distribution in pathogenic and commensal human enterobacteria. Colibactin-producing gut microbes promote colon tumour formation and enhance the progression of colorectal cancer via cellular senescence and death induced by DNA double-strand breaks (DSBs); however, the chemical basis that contributes to the pathogenesis at the molecular level has not been fully characterized. Here, we report the discovery of colibactin-645, a macrocyclic colibactin metabolite that recapitulates the previously assumed genotoxicity and cytotoxicity. Colibactin-645 shows strong DNA DSB activity in vitro and in human cell cultures via a unique copper-mediated oxidative mechanism. We also delineate a complete biosynthetic model for colibactin-645, which highlights a unique fate of the aminomalonate-building monomer in forming the C-terminal 5-hydroxy-4-oxazolecarboxylic acid moiety through the activities of both the polyketide synthase ClbO and the amidase ClbL. This work thus provides a molecular basis for colibactin's DNA DSB activity and facilitates further mechanistic study of colibactin-related colorectal cancer incidence and prevention.
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Cobre/farmacologia , Quebras de DNA de Cadeia Dupla/efeitos dos fármacos , Compostos Macrocíclicos/farmacologia , Peptídeos/farmacologia , Policetídeos/farmacologia , Cobre/química , Compostos Macrocíclicos/química , Conformação Molecular , Estresse Oxidativo/efeitos dos fármacos , Peptídeos/química , Policetídeos/químicaRESUMO
The worldwide prevalence of infections caused by antibiotic-resistant Gram-negative bacteria poses a serious threat to public health due to the limited therapeutic alternatives. Cationic peptides represent a large family of antibiotics and have attracted interest due to their diverse chemical structures and potential for combating drug-resistant Gram-negative pathogens. Here, we analyze 7395 bacterial genomes to investigate their capacity for biosynthesis of cationic nonribosomal peptides with activity against Gram-negative bacteria. Applying this approach, we identify two novel compounds (brevicidine and laterocidine) showing bactericidal activities against antibiotic-resistant Gram-negative pathogens, such as Pseudomonas aeruginosa and colistin-resistant Escherichia coli, and an apparently low risk of resistance. The two peptides show efficacy against E. coli in a mouse thigh infection model. These findings may contribute to the discovery and development of Gram-negative antibiotics.
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Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Genoma Bacteriano , Bactérias Gram-Negativas/efeitos dos fármacos , Ribossomos/metabolismo , Animais , Peptídeos Catiônicos Antimicrobianos/química , Células HeLa , Humanos , Camundongos , Testes de Sensibilidade MicrobianaRESUMO
The development of multidrug resistance (MDR) is the major obstacle in the chemotherapy of breast cancer, and it restricts the application of antitumor drugs in the clinic. Therefore it is urgent to search for ways to reverse MDR and restore sensitivity to chemotherapeutics in breast carcinoma. Currently, histone deacetylase inhibitors (HDACIs) offer a promising strategy for tumor therapy as the effective anticancer drugs. Based on the potential resistant target of nucleophosmin (NPM), the purpose of this study was to explore the reversal effect of a new synthetic histone deacetylase inhibitor, FA17, on MDR in methotrexate-resistant breast cancer cells (MCF-7/MTX) and xenograft tumors. It was shown that the abnormal expression of NPM induced MDR and inhibited downstream mitochondrial apoptotic pathway by activating PI3K/Akt signaling pathway in MCF-7/MTX cells. The reversal effect and molecular mechanism of FA17 were investigated both in vitro and in vivo. We found that FA17 could significantly reverse resistance and sensitize MCF-7/MTX cells to methotrexate. FA17 obviously enhanced resistant cell apoptosis, inhibited expressions of NPM and efflux transporters. Additionally, FA17 could reverse MDR via inactivating PI3K/Akt pathway and accelerating mitochondrial apoptotic pathway both in MCF-7/MTX cells and in xenograft tumors. Taken together, the novel histone deacetylase inhibitor could effectively reverse drug resistance due to suppressing the activity of NPM and drug efflux pumps by PI3K/Akt and mitochondrial apoptotic pathway. The above not only indicated the potential applied value of FA17 in reversing MDR and enhancing the sensitivity of chemotherapy, but also confirmed the role of NPM in the development of MDR in breast cancer.
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Neoplasias da Mama/tratamento farmacológico , Resistência a Múltiplos Medicamentos/genética , Resistencia a Medicamentos Antineoplásicos/genética , Inibidores de Histona Desacetilases/administração & dosagem , Animais , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Feminino , Regulação Neoplásica da Expressão Gênica/efeitos dos fármacos , Humanos , Células MCF-7 , Camundongos , Fosfatidilinositol 3-Quinases/genética , Proteínas Proto-Oncogênicas c-akt/genética , Transdução de Sinais/efeitos dos fármacos , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Horizontal gene transfer (HGT) of operational genes has been widely reported in prokaryotic organisms. However, informational genes such as those involved in transcription and translation processes are very difficult to be horizontally transferred, as described by Woese's complexity hypothesis. Here, we analyzed all of the completed prokaryotic genome sequences (2,143 genomes) in the NCBI (National Center for Biotechnology Information) database, scanned for genomes with high intragenomic heterogeneity of 16S rRNA gene copies, and explored potential HGT events of ribosomal RNA genes based on the phylogeny, genomic organization, and secondary structures of the ribosomal RNA genes. Our results revealed 28 genomes with relatively high intragenomic heterogeneity of multiple 16S rRNA gene copies (lowest pairwise identity <98.0%), and further analysis revealed HGT events and potential donors of the heterogeneous copies (such as HGT from Chlamydia suis to Chlamydia trachomatis) and mutation events of some heterogeneous copies (such as Streptococcus suis JS14). Interestingly, HGT of the 16S rRNA gene only occurred at intragenus or intraspecies levels, which is quite different from the HGT of operational genes. Our results improve our understanding regarding the exchange of informational genes.
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Transferência Genética Horizontal , Genes Arqueais , Genes Bacterianos , RNA Ribossômico 16S/genética , Chlamydia/genética , Escherichia coli/genética , Dosagem de Genes , Variação Genética , Genoma Arqueal , Genoma Bacteriano , Mutação , Filogenia , Thermoanaerobacter/genéticaRESUMO
A hypoxic/suboxic brine pool at a depth of about 850 m was discovered near the Thuwal cold seeps in the Red Sea. Filled with high concentrations of hydrogen sulfide and ammonia, such a brine pool might limit the spread of eukaryotic organisms. Here, we compared the communities of the eukaryotic microbes in a microbial mat, sediments and water samples distributed in 7 sites within and adjacent to the brine pool. Taxonomic classification of the pyrosequenced 18S rRNA amplicon reads showed that fungi highly similar to the species identified along the Arabic coast were almost ubiquitous in the water and sediment samples, supporting their wide distribution in various environments. The microbial mat displayed the highest species diversity and contained grazers and a considerable percentage of unclassified species. Phylogeny-based methods revealed novel lineages representing a majority of the reads from the interface between the sea water and brine pool. Phylogenetic relationships with more reference sequences suggest that the lineages were affiliated with novel Alveolata and Euglenozoa inhabiting the interface where chemosynthetic prokaryotes are highly proliferative due to the strong chemocline and halocline. The brine sediments harbored abundant species highly similar to invertebrate gregarine parasites identified in different oxygen-depleted sediments. Therefore, the present findings support the uniqueness of some microbial eukaryotic groups in this cold seep brine system.