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1.
J Environ Sci (China) ; 143: 23-34, 2024 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-38644020

RESUMO

Heavy metal(loid)s (HMs) pollution has become a common and complex problem in industrial parks due to rapid industrialization and urbanization. Here, soil and groundwater were sampled from a retired industrial park to investigate the pollution characteristics of HMs. Results show that Ni, Pb, Cr, Zn, Cd, and Cu were the typical HMs in the soil. Source analysis with the positive matrix factorization model indicates that HMs in the topsoil stemmed from industrial activities, traffic emission, and natural source, and the groundwater HMs originated from industrial activities, groundwater-soil interaction, groundwater-rock interaction, and atmosphere deposition. The sequential extraction of soil HMs reveals that As and Hg were mainly distributed in the residue fraction, while Ni, Pb, Cr, Zn, Cd, and Cu mainly existed in the mobile fraction. Most HMs either in the total concentration or in the bioavailable fraction preferred to retain in soil as indicated by their high soil-water partitioning coefficients (Kd), and the Kd values were correlated with soil pH, groundwater redox potential, and dissolved oxygen. The relative stable soil-groundwater circumstance and the low active fraction contents limited the vertical migration of soil HMs and their release to groundwater. These findings increase our knowledge about HMs pollution characteristics of traditional industrial parks and provide a protocol for HMs pollution scrutinizing in large zones.


Assuntos
Monitoramento Ambiental , Água Subterrânea , Metais Pesados , Poluentes do Solo , Solo , Poluentes Químicos da Água , Metais Pesados/análise , Água Subterrânea/química , Água Subterrânea/análise , Poluentes do Solo/análise , Poluentes Químicos da Água/análise , Solo/química , China
2.
Biotechnol Appl Biochem ; 70(2): 697-706, 2023 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35906824

RESUMO

Asymmetric reduction of (R)-carvone and ketoisophorone by an engineered ene-reductase from Galdieria sulphuraria (GsOYE) combined with glucose dehydrogenase for NADPH regeneration were studied. A semi-rational protein engineering was used to enhance the activity and selectivity of GsOYE. Upon the sequence alignment and molecular docking results, two amino acid residues at positions 66 and 270 were selected as saturation mutation sites. Finally, a single substitution variant of GsOYE-N270A with complete conversion (100%) and diastereoselectivity (dep >99%) for reduction of (R)-carvone and a double substitution variant GsOYE-Y66P/N270H with improved stereoselectivity for reduction of ketoisophorone were obtained.


Assuntos
Oxirredutases , Engenharia de Proteínas , Oxirredutases/metabolismo , Simulação de Acoplamento Molecular , Biocatálise
3.
Biotechnol Appl Biochem ; 70(5): 1720-1730, 2023 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-37073879

RESUMO

The amino acid residues at the entrance of the catalytic pocket may impose steric hindrance on the substrate to enter the active center of the enzyme. Based on the analysis of the three-dimensional structure of the Saccharomyces cerevisiae old yellow enzyme 3 (OYE3), four bulky residues were chosen and mutated to small amino acids. The results showed that mutation of the W116 residue had interesting impacts on the catalytic performance. All four variants became inactive for the reduction of (R)-carvone and (S)-carvone, but inverted the stereoselectivity for the reduction of (E/Z)-citral. The mutation of the F250 residue had a more positive effect on the activity and stereoselectivity. Two variants, F250A and F250S, showed excellent diastereoselectivity and activity for the reduction of (R)-carvone (de > 99%, c > 99%) and increased diastereoselectivity and activity for the reduction of (S)-carvone (de > 96%, c > 80%). One variant of the P295 residue, P295G, displayed excellent diastereoselectivity and activity only for the reduction of (R)-carvone (de > 99%, c > 99%). Mutation of the Y375 residue had a negative impact on the activity of the enzyme. These findings provide some solutions for rational enzyme engineering of OYE3.


Assuntos
Aminoácidos , NADPH Desidrogenase , NADPH Desidrogenase/química , NADPH Desidrogenase/genética , NADPH Desidrogenase/metabolismo , Monoterpenos Cicloexânicos , Catálise , Saccharomyces cerevisiae/metabolismo , Especificidade por Substrato
4.
Pestic Biochem Physiol ; 197: 105697, 2023 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-38072552

RESUMO

The improper use of deltamethrin (DM) can result in its accumulation in soil, water, food, and even the human body, which is associated with an elevated risk of neurotoxicity and behavioral abnormalities; however, the underlying mechanisms remain insufficiently investigated. Emerging evidence underscores the significance of the gut-brain axis in central nervous system (CNS) dysfunctions. Accordingly, this study investigates the role of the gut-brain axis in DM-induced behavioral anomalies in mice. The results showed that DM exposure induced depressive-like behavior, and the hippocampus, the region that is responsible for the modulation of emotional behavior, showed structural integrity disrupted (neuronal nuclear shrinkage and decreased tight junction protein expression). In addition, DM exposure led to compromised gut barrier integrity (disruptions on crypt surfaces and decreased tight junction protein expression), which might contribute to the gut bacterial-derived lipopolysaccharide (LPS) leakage into the bloodstream and reaching the brain, triggering LPS/toll-like receptor (TLR) 4 -mediated increases in brain pro-inflammatory cytokines. Subsequently, we observed a disturbance in neurotransmitter metabolic pathways following DM exposure, which inhibited the production of 5-hydroxytryptamine (5-HT). Additionally, DM exposure resulted in gut microbiota dysbiosis. Characteristic bacteria, such as Alistipes, Bifidobacterium, Gram-negative bacterium cTPY-13, and Odoribacter exhibited significant correlations with behavior, tight junction proteins, inflammatory response, and neurotransmitters. Further fecal microbiota transplantation (FMT) experiments suggested that DM-induced gut microbiota dysbiosis might contribute to depressive-like behavior. These results provide a new perspective on the toxicity mechanism of DM, indicating that its neurotoxicity may be partially regulated by the microbiota-gut-brain axis.


Assuntos
Eixo Encéfalo-Intestino , Lipopolissacarídeos , Camundongos , Humanos , Animais , Lipopolissacarídeos/toxicidade , Disbiose , Receptor 4 Toll-Like/metabolismo , Proteínas de Junções Íntimas
5.
Ecotoxicol Environ Saf ; 241: 113726, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35691195

RESUMO

The pathogenesis of brain inflammation induced by polychlorinated biphenyl 126 (PCB126) has not yet been fully illustrated. Growing evidence highlights the relevance of the microbiota-gut-brain axis in central nervous system (CNS) dysfunction. Therefore, we aimed to study the role of the gut microbiota in PCB126-induced proinflammatory cytokine increases in the mouse brain. The results showed that PCB126 exposure significantly disordered gut bacterial communities, resulting in the enrichment of gram-negative bacteria (e.g., Bacteroidetes and Proteobacteria), further leading to elevated levels of the gram-negative bacterial lipopolysaccharide (LPS). Subsequently, colonic toll-like receptor 4 (TLR-4) was activated by bacterial LPS, which promoted proinflammatory cytokine generation and inhibited tight junction (TJ) protein expression. Then, bacterial LPS translocated from the gut lumen into the blood circulation and reached the brain, triggering LPS/TLR-4-mediated increases in brain proinflammatory cytokines. Further analysis after fecal microbiota transplantation (FMT) suggested that the gut microbiota disturbance caused by PCB126 could induce elevated bacterial LPS and trigger TLR-4-mediated increases in proinflammatory cytokines in the brain. This study highlights the possibility that PCB126-induced gut microbiota disorder contributes to increased brain proinflammatory cytokines. These results provide a new perspective for identifying the toxicity mechanisms of PCB126 and open up the possibility of modulating the gut microbiota as a therapeutic target for CNS disease caused by environmental pollution.


Assuntos
Microbioma Gastrointestinal , Bifenilos Policlorados , Animais , Bactérias/metabolismo , Encéfalo/metabolismo , Eixo Encéfalo-Intestino , Citocinas/metabolismo , Disbiose/induzido quimicamente , Transplante de Microbiota Fecal , Microbioma Gastrointestinal/fisiologia , Lipopolissacarídeos , Camundongos , Bifenilos Policlorados/toxicidade , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo
6.
Environ Toxicol ; 35(4): 495-506, 2020 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31797534

RESUMO

Microplastics (MPs) pollution is a global paradigm that raises concern in relation to environment and human health. In order to investigate the molecular toxicity mechanisms of MPs, transcriptomic analyses were performed on in vitro Caco-2 cell model. After observing that polystyrene microplastics (PS-MPs) decreased cell viability in a dose-dependent manner, the responsible genes and involved pathways that might make contribution to PS-MBs-induced toxicity to Caco-2 cells were identified with Illumina RNA seq. A total of 442 genes including, 210 up-regulated ones and 232 down-regulated ones, showed differential expression after treatment by PS-MPs with a concentration of 12.5 mg L-1 or 50.0 mg L-1 for 24 hours. Gene Ontology (GO) annotation enriched unigenes can be grouped into three separated clusters: cellular component (CC), biological process (BP), and molecular function (MF). The dominate pathways related to NF-κB, MAPK signaling, cytokine-cytokine receptor interaction, and toll-like receptor were strongly influenced by PS-MBs. These pathways are involved in modulating cell inflammatory and proliferation. The qPCR were applied to investigate the transcriptional level of five proliferation related genes (Ras, ERK, MER, CDK4, Cyclin D1) and four inflammation related genes (TRPV1, iNOS, IL-1ß, IL-8), and the results were consistent with RNA-seq data. This study has provided new insight into the understanding of the toxicity effects of PS-MBs-induced intestinal inflammatory diseases.


Assuntos
Poluentes Ambientais/toxicidade , Microplásticos/toxicidade , Poliestirenos/toxicidade , Transcriptoma/efeitos dos fármacos , Células CACO-2 , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Regulação para Baixo , Perfilação da Expressão Gênica , Ontologia Genética , Humanos , Inflamação , Interleucina-1beta/genética , Microesferas , NF-kappa B/genética , Óxido Nítrico Sintase Tipo II/genética , Regulação para Cima
7.
J Basic Microbiol ; 60(8): 699-711, 2020 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-32510669

RESUMO

Bis(2-hydroxyethyl) terephthalate (BHET) is an important compound produced from poly(ethylene terephthalate) (PET) cleavage. It was selected as the representative substance for the study of PET degradation. A bacterial strain HY1 that could degrade BHET was isolated and identified as Enterobacter sp. The optimal temperature and pH for BHET biodegradation were determined to be 30°C and 8.0, respectively. The half-life of degradation was 70.20 h at an initial BHET concentration of 1,000 mg/L. The results of metabolites' analysis by liquid chromatograph-mass spectrometer revealed that BHET was first converted to mono-(2-hydroxyethyl) terephthalate (MHET) and then to terephthalic acid. Furthermore, an esterase-encoding gene, estB, was cloned from strain HY1, and the expressed enzyme EstB was characterized. The esterase has a molecular mass of approximately 25.13 kDa, with an isoelectric point of 4.68. Its optimal pH and temperature were pH 8.0 and 40°C, respectively. The analysis of the enzymatic products showed that EstB could hydrolyze one ester bond of BHET to MHET. To the best of authors' knowledge, this is the first report on the biodegradation characteristics of BHET by a member of the Enterobacter genus.


Assuntos
Proteínas de Bactérias/metabolismo , Enterobacter/metabolismo , Esterases/metabolismo , Ácidos Ftálicos/metabolismo , Sequência de Aminoácidos , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Biodegradação Ambiental , Enterobacter/classificação , Enterobacter/enzimologia , Enterobacter/genética , Esterases/química , Esterases/genética , Concentração de Íons de Hidrogênio , Hidrólise , Cinética , Peso Molecular , Filogenia , Especificidade por Substrato , Temperatura
8.
Microb Ecol ; 78(1): 6-19, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-30343437

RESUMO

Fasting influences the overall physiology of fish, and the knowledge how the gut microbiota, growth performances, and immune function in response to intermittent and long-term fasting is still insufficient. Here, we characterized the effects of fasting on the host-gut microbiota in crucian carp, which would enhance our insight into physiological adaptation to fasting. To achieve this, we investigated the gut microbial communities of crucian carp with different fasting stress, and corresponding immune and growth parameters. The gut microbial communities were structured into four clusters according to different fasting stress, namely one control group (feed regularly), two intermittent fasting groups (fasting period and re-feeding period, respectively), and one long-term fasting group. Intermittent fasting significantly improved the activity of superoxide dismutase (SOD) and lysozyme (LZM) (ANOVA, p < 0.05) and significantly increased alpha diversity and ecosystem stability of gut microbiota (ANOVA, p < 0.05). Gut length (GL) and condition factor (CF) showed no significant difference between the control group (CG) and intermittent fasting group under re-feeding period (RIF) (ANOVA, p = 0.11), but relative gut length (RGL) in group RIF was higher than that in the CG (ANOVA, p = 0.00). The bacterial genera Bacteroides, Akkermansia, and Erysipelotrichaceae were enriched in fishes under intermittent fasting. Two Bacteroides OTUs (OTU50 and OTU1292) correlated positively with immune (SOD, complement, and LZM) and growth (GL and RGL) parameters. These results highlight the possible interplay between growth performances, immune function, and gut microbiota in response to fasting.


Assuntos
Bactérias/isolamento & purificação , Carpas/imunologia , Carpas/microbiologia , Microbioma Gastrointestinal , Intestinos/microbiologia , Adaptação Fisiológica , Animais , Bactérias/classificação , Bactérias/genética , Carpas/metabolismo , Jejum , Intestinos/imunologia
9.
Appl Microbiol Biotechnol ; 103(23-24): 9723-9737, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31728586

RESUMO

Gut microbiome critically contributes to host health status. Thus, investigating the relationship between the gut microbiome and toxic chemicals is a hot topic in toxicology research. Exposure to malachite green (MG) has been linked to various health disorders. Thus, exploring the gut microbiota changes in response to MG would provide a new perspective on the toxicity effects of this chemical substance. MG exposure resulted in the significantly lower alpha diversity (Mann-Whitney U test, z = - 6.83, p = 0.00) but higher beta diversity (Mann-Whitney U test, z = - 1.98, p = 0.04) of gut microbiota, and significantly decreased ecosystem stability (alpha and beta variability; Mann-Whitney U test, all p < 0.05) of gut microbial communities. Gut bacterial networks showed that the interactions became more complex and stronger after MG exposure, which could decrease the stability of the network. Changes in gut microbiota composition were mainly reflected in the enrichment of opportunistic bacteria (i.e., Aeromonas and Vibrio) and the depression of fermentative bacteria (i.e., Bacteroides and Paludibacter). MG exposure leads to a significantly increased gut permeability (lipopolysaccharide-binding protein; Mann-Whitney U test, z = - 6.92, p = 0.00), which could reduce the host selective pressures on particular bacterial species (such as members in Aeromonas and Vibrio). This result was further supported by the weakened importance of a deterministic microbial assembly after MG exposure. All these findings indicated that MG exposed fishes might have more possibilities to be infected, as demonstrated by the enrichment of opportunistic pathogenic bacteria, high-level immune responses, and increased gut permeability. These findings greatly improve our understanding of the toxicity effects of MG.


Assuntos
Bactérias/efeitos dos fármacos , Microbioma Gastrointestinal/efeitos dos fármacos , Corantes de Rosanilina/toxicidade , Animais , Peixes/microbiologia , RNA Ribossômico 16S
10.
Biotechnol Lett ; 41(10): 1223-1232, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31456128

RESUMO

OBJECTIVE: To purify an esterase which can selectively hydrolyze (R,S)-ethyl indoline-2-carboxylate to produce (S)-indoline-2-carboxylic acid and characterize its enzymatic properties. RESULTS: An intracellular esterase from Bacillus aryabhattai B8W22 was isolated and the purified protein was identified as a carboxylesterase by MALDI-TOF mass spectrometry. The enzyme (named BaCE) was 59.03-fold purification determined to be of approximately 35 kDa. Its specific activity was 0.574 U/mL with 20% yield. The enzyme showed maximum activity at pH 8.5 and 30 °C and was stable at 20-30 °C using pNPB as the substrate. The Km, Vmax, kcat and kcat/Km of the esterase were 0.52 mM, 6.39 µM/min, 26.87 min-1 and 51.67 mM/min, respectively. The esterase demonstrated high enantioselectivity toward (S)-ethyl indoline-2-carboxylate with 96.55% e.e.p at 44.39% conversion, corresponding to an E value of 133.45. CONCLUSIONS: In this study, a new esterase BaCE with an apparent molecular mass of 35 kDa was purified to homogeneity for the first time. The esterase from Bacillus aryabhattai B8W22 was isolated with a purification more than 59-fold and a yield of 20% by anion exchange chromatography and hydrophobic interaction chromatography. And its biochemical characterization were described in detail with pNPB as substrate. It displayed high enantioselectivity toward (S)-ethyl indoline-2-carboxylate. We next plan to highly express esterase BaCE in Escherichia coli, and apply it to industrial production of (S)-indoline-2-carboxylic acid.


Assuntos
Bacillus/enzimologia , Esterases/isolamento & purificação , Esterases/metabolismo , Indóis/metabolismo , Biotransformação , Estabilidade Enzimática , Esterases/química , Concentração de Íons de Hidrogênio , Cinética , Peso Molecular , Especificidade por Substrato , Temperatura
11.
Environ Toxicol ; 34(6): 742-752, 2019 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-30835936

RESUMO

Brominated flame retardants (BFRs) are supposed to act as disruptors of cell signaling, but the underlying mechanisms remain less clear. Human bronchial epithelial cells (BEAS-2B) were used to investigate the toxic effect and gene expression changes induced by tetrabromobisphenol A (TBBPA). By genome-wide approaches with Illumina RNA-seq, 87 genes were identified to exhibit ≥1.5-fold changes in expression after treatment by TBBPA for 48 h, among which, 79 were upregulated and 8 were downregulated. Gene ontology (GO) annotation enriched unigenes were divided into three clusters: biological process (BP), cellular component (CC) and molecular function (MF). Pathway analysis showed that NF-κB, TNF signaling, toll-like receptor, MAPK signaling and B-cell receptor were the most prominent pathways affected by TBBPA, which play key roles in regulating cell proliferation and cell differentiation, inflammatory response. Finally, for verifying the accuracy of microarray analysis, qRT-PCR was used to analyze the transcription level of key genes in the above signaling pathways, and ELISA assay confirmed the effect of TBBPA on the levels of CXCL-2, CCL-3, CCL-4, IL-1ß, TNF-α, and IL-6. These findings provided important information for further exploitation of the mechanisms under-lying BFR-induced adverse health effects.


Assuntos
Células Epiteliais/efeitos dos fármacos , Retardadores de Chama/toxicidade , Bifenil Polibromatos/toxicidade , Transcriptoma/efeitos dos fármacos , Linhagem Celular , Células Epiteliais/metabolismo , Perfilação da Expressão Gênica , Ontologia Genética , Estudo de Associação Genômica Ampla , Humanos , Transdução de Sinais , Regulação para Cima
12.
Environ Toxicol ; 33(12): 1245-1253, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30098271

RESUMO

The cellular toxicity response of human airway epithelial cells (A549) to tetrabromobisphenol (TBBPA) was assessed in vitro. Cell viability, levels of intracellular reactive oxygen species (ROS), lipid peroxidation (MDA), and caspase-3 activity were determined after A549 treated with varying concentrations of TBBPA. A comparative proteomic analysis was performed in cells treated with different concentrations of TBBPA (0, 10, and 40 µg/mL). Two-way anova analysis showed that cell viability was significantly decreased after treatment by TBBPA with a concentration of 16 µg/mL for 48 hr, however, the caspase-3 activities, ROS generation, and MDA content increased. Ultrastructural observation revealed that the cell was morphological damaged after exposure to 64 µg/mL TBBPA, with mitochondria seriously injured and the smooth endoplasmic reticulum dilated. There was a good correlation between ROS generation and mitochondrial dysfunction. Seventeen differentially expressed proteins involved in various biological processes were identified. These findings provide a basis for understanding the mechanisms of cell dysfunction and perturbation of antioxidant status induced by additive flame retardant on airway epithelial cells.


Assuntos
Células Epiteliais/efeitos dos fármacos , Retardadores de Chama/toxicidade , Bifenil Polibromatos/toxicidade , Proteoma/efeitos dos fármacos , Mucosa Respiratória/efeitos dos fármacos , Células A549 , Animais , Sobrevivência Celular/efeitos dos fármacos , Células Epiteliais/metabolismo , Humanos , Peroxidação de Lipídeos/efeitos dos fármacos , Mitocôndrias/metabolismo , Proteoma/metabolismo , Proteômica , Espécies Reativas de Oxigênio/metabolismo , Mucosa Respiratória/metabolismo , Mucosa Respiratória/fisiologia , Testes de Toxicidade
13.
Appl Microbiol Biotechnol ; 100(8): 3735-45, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26695154

RESUMO

The environmental risk of fluoride and chloride pollution is pronounced in soils adjacent to solar photovoltaic sites. The elevated levels of fluoride and chloride in these soils have had significant impacts on the population size and overall biological activity of the soil microbial communities. The microbial community also plays an essential role in remediation of these soils. Questions remain as to how the fluoride and chloride contamination and subsequent remediation at these sites have impacted the population structure of the soil microbial communities. We analyzed the microbial communities in soils collected from close to a solar photovoltaic enterprise by pyrosequencing of the 16S rRNA tag. In addition, we used multivariate statistics to identity the relationships shared between sequence diversity and heterogeneity in the soil environment. The overall microbial communities were surprisingly diverse, harboring a wide variety of taxa and sharing significant correlations with different degrees of fluoride and chloride contamination. The contaminated soils harbored abundant bacteria that were probably resistant to the high acidity, high fluoride and chloride concentration, and high osmotic pressure environment. The dominant genera were Sphingomonas, Subgroup_6_norank, Clostridium sensu stricto, Nitrospira, Rhizomicrobium, and Acidithiobacillus. The results of this study provide new information regarding a previously uncharacterized ecosystem and show the value of high-throughput sequencing in the study of complex ecosystems.


Assuntos
Bactérias/isolamento & purificação , Bactérias/efeitos da radiação , Biodiversidade , RNA Ribossômico 16S/genética , Microbiologia do Solo , Bactérias/classificação , Bactérias/genética , Sequenciamento de Nucleotídeos em Larga Escala , Filogenia , Energia Solar
14.
Guang Pu Xue Yu Guang Pu Fen Xi ; 35(1): 65-70, 2015 Jan.
Artigo em Zh | MEDLINE | ID: mdl-25993822

RESUMO

The seal stone is a kind of artwork with historical and cultural characteristics of China, which has been playing an important role in Chinese traditional culture. "Gaozhou stone", a new kind of the seal stone, has been found in the market recently. To investigate the mineralogical and spectral characterastics of "Gaozhou stone", samples were studied by using XRF, XRD, FTIR, SEM and DTA. Measurements by XRD reveal that kaolin minerals (kaolinite, dickite), pyrophyllite and minor sericite and illite occur in the ores. When kaolinite and dickite are associated, it is not easy to differentiate them from each other. Although some reflections overlap others, kaolin polytypes can be differentiated by XRD patterns in the range 18°-40° (2θ), the reflections at 0. 395, 0. 379, 0. 343, 0. 326, 0. 294, 0. 280, 0. 232 and 0. 221 nm are diagnostic of dickite. The XRD results indicate the presence of transitional mineral of kaolinite and dickite in these samples. The main chemical components of "Gaozhou stone" are SiO2 and Al2O3 with minor Fe2O3, K2O and Na2O, corresponding with that of kaolin minerals. The OH groups in kaolin group minerals have attracted considerable attention as a sensitive indicator of structural disorder. In principle, dickite has three bands, whereas kaolinite has four bands at the OH-stretching region. According to the results of FTIR, transitional mineral of kaolinite and dickite in "Gaozhou stone" has 3 absorption bands of 3 670, 3 650 and 3 620 cm-1 in high frequency region. The intensity of 3 670 cm-1 band that belongs to outer layer hydroxyl vibration is approximately equal to the intensity of 3 620 cm band ascribing to inner layer OH vibration. This value will only have subtle changes due to the different component ratio of kaolinite and dickite layers. Micro-morphology viewed by SEM presents irregular platy or pseudo-hexagonal platy particles with an average diameter of 0. 5-4 µm of "Gaozhou stone". Such morphologies are quite similar to other seal stones of China that the formation environments of all these stones are of the same kind. DTA curves demonstrate that the disparity of dehydroxylation temperature can be seen as a differential feature for identifying kaolin group minerals, but that is not undoubted. And what's more, the size of the mineral grains seems has a greater effect on the disparity of dehydroxylation temperature. This research shows that the mineral type of "Gaozhou stone" is similar to "Four Famous stones of China", and it could be a viable substitute of other famous seal stones. In this point, "Gaozhou stone" has a broad market prospect.

15.
Biotechnol Appl Biochem ; 61(5): 549-54, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24372644

RESUMO

The metabolic peculiarities of anthracene and pyrene by Pycnoporus sanguineus H1 were investigated. The fungus H1 could grow on potato dextrose agar plates with anthracene and anthraquinone as carbon sources. In liquid medium, the strain degraded 8.5% of anthracene as the sole carbon source, with no ligninolytic enzymes detected, indicating that intracellular catabolic enzymes might be responsible for the initial oxidation of anthracene. When bran was added to the medium, the degradation rate of anthracene and pyrene increased to 71.3% and 30.2%, respectively, and the laccase activities increased to a maximal value of 501.2 and 587.6 U/L, respectively. By gas chromatography-mass spectrometry analysis, anthraquinone was detected as the unique intermediate product of anthracene oxidation, with a yield molar ratio of 0.3. In vitro experiments showed that the extracellular culture fluid containing laccase transformed anthracene to anthraquinone with a yield molar ratio of 1.0, which was less than that of the in vivo experiment, indicating that anthraquinone could be further metabolized by the strain. Pyrene could not be oxidized by culture fluid. These results showed that both extracellular laccase and intracellular catabolic enzymes might play an important role in the initial oxidation of anthracene, whereas pyrene could be only oxidized by intracellular catabolic enzymes through cometabolism.


Assuntos
Antracenos/metabolismo , Proteínas Fúngicas/metabolismo , Lacase/metabolismo , Pycnoporus/enzimologia , Pirenos/metabolismo , Biodegradação Ambiental , Meios de Cultura , Proteínas Fúngicas/química , Lacase/química , Eletroforese em Gel de Poliacrilamida Nativa , Oxirredução
16.
Bioprocess Biosyst Eng ; 37(7): 1377-84, 2014 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-24385153

RESUMO

In the present study, the ability of a newly isolated strain, Methylobacterium sp. XJLW to degrade formaldehyde was investigated in shake flasks and in a bioreactor. The resting cells of Methylobacterium sp. XJLW showed high formaldehyde tolerance (60 g L(-1)) and high degradation rate (1,687.5 mg L(-1) h(-1)) in shake flasks. This biodegradation was initiated by a dismutation reaction since formic acid was formed and caused significant dropping of pH in the media. The addition of CaCO(3) to the media was found as an effective strategy to control the pH and keep the cells in high degradation bioactivity. A three-phase fluidized bed reactor (TPFBR) was designed to test the formaldehyde-biodegrading ability of immobilized Methylobacterium sp. XJLW. Using a repeated-batch degradation mode, the immobilized cells were able to degrade 5 g L(-1) formaldehyde (with a maximal degradation rate of 464.5 mg L(-1) h(-1) under the optimum conditions) and showed stable bioactivity after 20 batches of reuse in the TPFBR.


Assuntos
Reatores Biológicos/microbiologia , Biotecnologia/métodos , Formaldeído/química , Methylobacterium/metabolismo , Biodegradação Ambiental , Carbonato de Cálcio/química , Células Imobilizadas , Meios de Cultura/química , Desenho de Equipamento , Formiatos/química , Concentração de Íons de Hidrogênio , Fatores de Tempo
17.
Environ Eng Sci ; 31(1): 9-17, 2014 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-24550665

RESUMO

The aim of this study was to evaluate the acute toxicity effects of dichloromethane and dichloroethane on Chlorella vulgaris at the physiological and molecular level. Data showed that the cell number, chlorophyll a, and total protein content gradually decreased with increasing dichloromethane and dichloroethane concentrations over a 96-h exposure. Lower doses of two organic solvents had stimulatory effects on catalase and superoxide dismutase activity. Malondialdehyde showed a concentration-dependent increase in response to dichloromethane and dichloroethane exposure. Electron microscopy also showed that there were some chloroplast abnormalities in response to different concentrations of dichloromethane and dichloroethane exposure. Real-time polymerase chain reaction assay demonstrated that dichloromethane and dichloroethane reduced the transcript abundance of psaB, whereas that of psbC changed depending on the toxicant after 24 h of exposure. Dichloromethane and dichloroethane affected the activity of antioxidant enzymes, disrupted the chloroplast ultrastructure, and reduced transcription of photosynthesis-related genes in C. vulgaris, leading to metabolic disruption and cell death.

18.
Ther Adv Psychopharmacol ; 14: 20451253241227772, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38322010

RESUMO

Bipolar disorder (BD) is a severe mental disorder with various hypotheses regarding its pathogenesis. This article provides a summary of numerous studies on the variations in inflammatory cytokine levels in patients with BD and the effects of treatment with antipsychotics, mood stabilizers, and antidepressants on these levels. In addition, patients with autoimmune diseases who use anti-inflammatory monoclonal antibodies experience symptoms, such as depression, anxiety, and insomnia. These pieces of evidence suggest a potential association between immune inflammation and BD and offer new possibilities for therapy. Building upon this relationship, the authors propose an innovative approach for treating BD through individualized and precise therapy using anti-inflammatory monoclonal antibody drugs. To support this proposal, the authors compile information on pharmacological effects and relevant studies, including trials of various anti-inflammatory therapeutic monoclonal antibody drugs (e.g. infliximab, tocilizumab, and canakinumab) for the potential treatment of BD and its associated side effects in psychiatry. The authors categorize these anti-inflammatory monoclonal antibody drugs into levels I-IV through a comprehensive analysis of their advantages and disadvantages. Their potential is examined, and the need for further exploration of their pharmaceutical effects is established.

19.
Int J Biol Macromol ; 264(Pt 1): 130427, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38428763

RESUMO

The asymmetric reduction of α, ß-unsaturated compounds conjugated with electron-withdrawing group by ene-reductases (ERs) is a valuable method for the synthesis of enantiopure chiral compounds. This study introduced an ER from Corynebacterium casei (CcER) which was heterologously expressed in Escherichia coli BL21(DE3), and the purified recombinant CcER was characterized for its biocatalytic properties. CcER exhibited the highest specific activity at 40 °C and pH 6.5, and showcased appreciable stability below 40 °C over a pH range of 6.0-7.0. The enzyme displayed high resistance to methanol. CcER accepted NADH or NADPH as a cofactor and exhibited a broad substrate spectrum towards α, ß-unsaturated compounds. It achieved complete conversion of 2-cyclohexen-1-one and good performance for stereoselective reduction of (R)-carvone (conversion 98 %, diastereoselectivity 96 %). This study highlights the robustness and potential of CcER.


Assuntos
Corynebacterium , Oxirredutases , Oxirredutases/metabolismo , NADP/metabolismo , Especificidade por Substrato
20.
Microb Biotechnol ; 16(4): 827-837, 2023 04.
Artigo em Inglês | MEDLINE | ID: mdl-36722318

RESUMO

Bloodstream infections are serious and complex infectious diseases that often require a rapid diagnosis. Polymerase chain reaction coupled with quantum dot fluorescence analysis (PCR-QDFA) is a novel diagnostic technique. This study aimed to evaluate the diagnostic performance of PCR-QDFA for pathogen detection in patients with suspected bloodstream infections (BSIs). It evaluates 29 kinds of common pathogens (24 bacteria and 5 yeasts) from blood culture bottles. The results of PCR-QDFA identification and traditional microbial laboratory identification were compared, and the latter was used as the 'gold standard' to analyse the diagnostic performance of the PCR-QDFA. In total, 517 blood culture bottles were included in this study. The PCR-QDFA identified microorganisms in 368/422 (87.2%) samples with monomicrobial growth. For the pathogens on the PCR-QDFA list, the assay showed a higher sensitivity of 97.4% (368/378). When polymicrobial growth was analysed, the PCR-QDFA successfully detected 19/25 (76%) microorganisms on the PCR-QDFA list. In addition, 82/82 negative blood culture bottles also showed no pathogens by PCR-QDFA with a specificity of 100%. In conclusion, the PCR-QDFA assay could identify a majority of the common pathogens encountered in clinical practice, showing excellent diagnostic performance for pathogen detection in patients with suspected BSIs.


Assuntos
Pontos Quânticos , Sepse , Humanos , Sepse/diagnóstico , Bactérias/genética , Reação em Cadeia da Polimerase/métodos , Leveduras/genética , Sensibilidade e Especificidade
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