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1.
Org Biomol Chem ; 21(34): 6926-6931, 2023 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-37578205

RESUMO

Reported here is the synthesis of a naphthalene-based macrocycle bearing anionic carboxylato groups on the rims along with its complexation with cationic guests in aqueous media. The macrocycle could strongly bind guests in a molecular clip model with association constants of 106-107 M-1.

2.
Environ Res ; 209: 112732, 2022 06.
Artigo em Inglês | MEDLINE | ID: mdl-35077715

RESUMO

Decomposing cyanobacterial bloom-induced black blooms been seen as an issue in the management of freshwater ecosystems, but its effect on sulfate-reducing bacteria (SRB) in shallow freshwater lakes is not clear. The objective of this study is to present an in-depth investigation of black bloom effects on the activities and composition of SRB, as well as the interactions between SRB and other bacteria. Water and surface sediments samples were collected from a shallow freshwater lake during black and non-black blooms. Sulfate reduction rates (SRRs) in the water column were determined from the linear regression of sulfate depletion with time. Quantitative real-time polymerase chain reactions (qPCRs), targeting the dsrA gene and Illumina sequencing of 16S rDNA, were used to estimate the SRB population and SRB community structures, respectively. Our data indicate that although a higher abundance of SRB was responsible for the higher SRR in the bottom water (34.09 ±â€¯2.37 nmol mL-1 day-1) than in the surface water (14.57 ±â€¯2.91 nmol mL-1 day-1) during black blooms, cell-specific sulfate reduction rates (csSRRs) in the distinct water layers were not significantly different (P = 0.95), with the value of approximately 0.017 fmol cell-1 day-1. Additionally, Desulfomicrobium and Desulfovibrio were the two main genera of SRB in the water column during black bloom season, while Desulfobulbus, Desulfobacca and Desulfatiglans genera were identified in the sediments of both the black and non-black blooms in genera pools. Each SRB genus preferentially associated with bacteria for specific functions in the bacterial co-occurrence network, regardless of whether black booms occurred or not. These results extend our knowledge on the importance of SRB during black blooms and the adaptation of SRB to environmental changes in freshwater lakes.


Assuntos
Cianobactérias , Lagos , Ecossistema , Eutrofização , Lagos/química , Sulfatos
3.
Appl Microbiol Biotechnol ; 105(13): 5407-5417, 2021 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-34155529

RESUMO

Fungal terpenoids catalyzed by bifunctional terpene synthases (BFTSs) possess interesting bioactive and chemical properties. In this study, an integrated approach of genome mining, heterologous expression, and in vitro enzymatic activity assay was used, and these identified a unique BFTS sub-clade critical to the formation of a 5-15 trans-fused bicyclic sesterterpene preterpestacin I (1). The 5-15 bicyclic BFTS gene clusters were highly conserved but showed relatively wide phylogenetic distribution across several species of the diverged fungal classes Dothideomycetes and Sordariomycetes. Further genomic organization analysis of these homologous biosynthetic gene clusters from this clade revealed a glycosyltransferase from the graminaceous pathogen Bipolaris sorokiniana isolate BS11134, which was absent in other 5-15 bicyclic BFTS gene clusters. Targeted isolation guided by BFTS gene deletion led to the identification of two new sesterterpenoids (4, and 6) from BS11134. Compounds 2 and 4 showed moderate effects on LPS-induced nitrous oxide production in the murine macrophage-like cell line RAW264.7 with in vitro inhibition rates of 36.6 ± 2.4% and 24.9 ± 2.1% at 10 µM, respectively. The plausible biosynthetic pathway of these identified compounds was proposed as well. This work revealed that phytopathogenic fungi can serve as important sources of active terpenoids via systematic analysis of the genomic organization of BFTS biosynthetic gene clusters, their phylogenetic distribution in fungi, and cyclization properties of their metabolic products. KEY POINTS: • Genome mining of the first BFTS BGC harboring a glycosyltransferase. • Gene-deletion guided isolation revealed three novel 5-15 bicyclic sesterterpenoids. • Biosynthetic pathway of isolated sesterterpenoids was proposed.


Assuntos
Vias Biossintéticas , Fungos , Animais , Anti-Inflamatórios , Vias Biossintéticas/genética , Fungos/genética , Camundongos , Família Multigênica , Filogenia , Terpenos
4.
Appl Microbiol Biotechnol ; 104(4): 1545-1553, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31897521

RESUMO

Increasing attention has recently been focused on complex symbiotic associations, for instance coral and its symbionts. Sea cucumber, harboring diverse fungi, has also attracted more and more attention for their functional diversity. Here, secondary metabolites produced by Chaetomium globosum associated with sea cucumber, Apostichopus japonicus, were investigated using gene mining with third-generation sequencing technology (PacBio SMRT). Nine compounds, including one new compound cytoglobosin X (1), were isolated from cultures of Chaetomium globosum. Compound 1 was identified based on NMR data, HRESIMS, and ECD, and the absolute configurations were identified as 3S, 4R, 7S, 8R, 9R, 16S, 19S, 20S, and 23S. In an antimicrobial assay, compound 4 showed moderate activity against Staphylococcus aureus and methicillin-resistant Staphylococcus aureus with MICs of 47.3 and 94.6 µM, respectively. Our results suggest that the microbiomes associated with sea cucumber could be an important resource for biodiversity and structural novelty, and the bioactive compounds may protect the host from pathogen microbial.


Assuntos
Antibacterianos/farmacologia , Bactérias/efeitos dos fármacos , Benzopiranos/farmacologia , Chaetomium/química , Alcaloides Indólicos/farmacologia , Pigmentos Biológicos/farmacologia , Stichopus/microbiologia , Animais , Antibacterianos/isolamento & purificação , Benzopiranos/isolamento & purificação , Sequenciamento de Nucleotídeos em Larga Escala , Alcaloides Indólicos/isolamento & purificação , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pigmentos Biológicos/isolamento & purificação , Metabolismo Secundário , Staphylococcus aureus/efeitos dos fármacos , Simbiose
5.
Sensors (Basel) ; 20(10)2020 May 13.
Artigo em Inglês | MEDLINE | ID: mdl-32414203

RESUMO

Soil organic matter (SOM) refers to all carbon-containing organic matter in soil and is oneof the most important indicators of soil fertility. The hyperspectral inversion analysis of SOMtraditionally relies on laboratory chemical testing methods, which have the disadvantages of beinginefficient and time-consuming. In this study, 69 soil samples were collected from the Honghufarmland area and a mining area in northwest China. After pretreatment, 10 spectral indicators wereobtained. Ridge regression, kernel ridge regression, Bayesian ridge regression, and AdaBoostalgorithms were then used to construct the SOM hyperspectral inversion model based on thecharacteristic bands, and the accuracy of the models was compared. The results showed that theAdaBoost algorithm based on a grid search had the best accuracy in the different regions. For themining area in northwest China [...].

6.
Int J Syst Evol Microbiol ; 67(6): 1813-1819, 2017 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-28604335

RESUMO

A Gram-stain-negative, rod-shaped bacterium, strain F01T, was isolated from leaves of Tamarix chinensis Lour. The isolate grew optimally at 30 °C, at pH 7.0 and with 5.0 % (w/v) NaCl, and showed a high tolerance to manganese, lead, nickel, ferrous ions and copper ions. The major fatty acids were C18 : 1ω7c and C16 : 0, and the predominant respiratory quinone was Q-9. Polar lipids were dominated by diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylglycerol, unidentified aminoglycolipids and phospholipids. The DNA G+C content was 65.8 %. Based on multilocus phylogenetic analysis, strain F01T belonged to the genus Salinicola, with highest 16S rRNA gene sequence similarity to Salinicola peritrichatus CGMCC 1.12381T (97.7 %). The level of DNA-DNA hybridization between strain F01T and closely related Salinicola strains was well below 70 %. According to the phenotypic, genetic and chemotaxonomic data, strain F01T is considered to represent a novel species in the genus Salinicola, for which the name Salinicola tamaricis sp. nov. is proposed. The type strain is F01T (=CCTCC AB 2015304T=KCTC 42855T).


Assuntos
Halomonadaceae/classificação , Filogenia , Plantas Tolerantes a Sal/microbiologia , Tamaricaceae/microbiologia , Técnicas de Tipagem Bacteriana , Composição de Bases , China , DNA Bacteriano/genética , Ácidos Graxos/química , Halomonadaceae/genética , Halomonadaceae/isolamento & purificação , Metais , Hibridização de Ácido Nucleico , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/química
7.
Am J Dent ; 30(5): 262-266, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-29178729

RESUMO

PURPOSE: To evaluate the effect of simulated toothbrush abrasion on the surface gloss, the surface roughness and the color stability of incrementally-filled and bulk-fill composites. METHODS: 48 dimensionally standardized composite specimens (n= 8/group) were made from four incrementally-filled composites (Tetric EvoCeram, IPS Empress Direct Enamel, Ceram X mono and Arabesk) and two bulk-fill composites (Quix fil and Tetric EvoCeram Bulk). Before and after toothbrushing simulation the surface gloss was measured by a glossmeter, the surface roughness was evaluated with a profilometer, and the color was measured using a spectrophotometer. RESULTS: Before and after the toothbrush abrasion, IPS Empress Direct Enamel yielded the highest gloss value, while Ceram X mono exhibited the lowest gloss value. Quix fil showed the highest Ra value before the toothbrushing simulation, however, it showed similar Ra value with Ceram X mono and Arabesk after the toothbrushing simulation. IPS Empress Direct Enamel showed the lowest ΔE after the simulated toothbrushing. Tetric EvoCeram Bulk showed similar gloss value, Ra value, and ΔE to Tetric EvoCeram after the toothbrushing simulation. Simple regression analysis showed no correlation between the roughness and the gloss, but it showed a positive linear relationship between ΔE and ΔRa. (R2= 0.863, P= 0.027). CLINICAL SIGNIFICANCE: The evaluated bulk-fill composites did not exhibit significantly worse surface properties and color stability than incrementally-filled materials after toothbrush abrasion. Color changes of composites caused by toothbrush abrasion were acceptable on the premise that 3.3ΔE units were considered as acceptable threshold values.


Assuntos
Polimento Dentário , Escovação Dentária , Cor , Resinas Compostas , Teste de Materiais , Propriedades de Superfície
8.
Chin J Cancer ; 34(11): 522-30, 2015 Sep 14.
Artigo em Inglês | MEDLINE | ID: mdl-26370464

RESUMO

BACKGROUND: The regimen of cyclophosphamide, doxorubicin, vincristine, and prednisolone (CHOP) is an efficient treatment of non-Hodgkin's lymphoma (NHL). This study aimed to assess the efficacy and toxicity of dose-adjusted CHOP alone or in combination with rituximab (R-CHOP) by examining the stem cell mobilization in NHL patients. Factors affecting the collection of CD34+ cells were also explored. METHODS: Our retrospective study included 39 patients eligible for autologous stem cell transplantation: 14 patients who expressed CD20 and were financially eligible received R-CHOP for autologous peripheral blood stem cell (APBSC) mobilization; the remaining 25 patients received CHOP. RESULTS: The median CD34+ cell yield was 7.01×10(6) cells/kg body weight (range 1.49-28.39×10(6) cells/kg body weight), with only two patients failing to meet the target CD34+ cell harvest of ≥2.0×10(6) cells/kg body weight. The median number of apheresis procedures per patient was 1 (range 1-3). The APBSC mobilization yield of the CHOP group appeared to be higher than that of the R-CHOP group (P=0.005), whereas the success rate was similar between groups. R-CHOP elevated the complete response (CR) rate in B cell lymphoma patients as compared with CHOP (P=0.01). No significant differences in toxicity or engraftment were observed between the two groups. CONCLUSION: The present study demonstrated that dose-adjusted CHOP chemotherapy effectively mobilized APBSCs in NHL patients and that the addition of rituximab to dose-adjusted CHOP chemotherapy elevated the CR rate for patients with B-cell lymphoma.


Assuntos
Protocolos de Quimioterapia Combinada Antineoplásica , Mobilização de Células-Tronco Hematopoéticas , Linfoma não Hodgkin , Rituximab , Anticorpos Monoclonais Murinos , Ciclofosfamida , Doxorrubicina , Transplante de Células-Tronco Hematopoéticas , Humanos , Linfoma de Células B , Prednisolona , Prednisona , Indução de Remissão , Estudos Retrospectivos , Vincristina
9.
Chin J Cancer Res ; 27(1): 66-73, 2015 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-25717228

RESUMO

OBJECTIVE: The study evaluated the effectiveness of autologous hematopoietic stem cell transplantation (AHSCT) in the treatment of lymphoblastic lymphoma (LL). METHODS: We retrospectively analyzed the data from 41 patients with chemotherapy-sensitive LL who underwent hematopoietic stem cell transplantation (HSCT) from December 1989 to December 2009 in a single institution. RESULTS: HSCT was conducted as first-line consolidation therapy and salvage therapy in 36 and 5 patients, respectively. The median follow-up was 97.1 months (range, 24.6-173.1 months). The 5-year overall survival (OS) and event-free survival (EFS) rate were 64% and 47% for the initially treated patients, respectively, and were both 20% for the relapsed ones. Bone marrow (BM) involvement and chemotherapy cycles prior to transplantation were identified as significant prognostic factors for EFS in multivariate analysis. CONCLUSIONS: These results confirm that AHSCT is a reasonable option for chemotherapy-sensitive LL patients in first complete remission (CR1).

10.
Cancer Innov ; 3(6): e147, 2024 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-39398261

RESUMO

The tumor microenvironment (TME) facilitates tumor development through intricate intercellular signaling, thereby supporting tumor growth and suppressing the immune response. Thyroid hormone receptor interactor 13 (TRIP13), an AAA+ ATPase, modulates the conformation of client macromolecules, consequently influencing cellular signaling pathways. TRIP13 has been implicated in processes such as proliferation, invasion, migration, and metastasis during tumor progression. Recent studies have revealed that TRIP13 also plays a role in immune response suppression within the TME. Thus, inhibiting these functions of TRIP13 could potentially enhance immune responses and improve the efficacy of immune checkpoint inhibition. This review summarizes the recent research progress of TRIP13 and discusses the potential of targeting TRIP13 to improve immune-based therapies for patients with cancer.

11.
Plants (Basel) ; 13(8)2024 Apr 12.
Artigo em Inglês | MEDLINE | ID: mdl-38674491

RESUMO

Phytolacca americana, introduced to China in the 20th century for its medicinal properties, has posed a significant ecological and agricultural challenge. Its prolific fruit production, high reproductive coefficient, adaptability, and toxic roots and fruits have led to the formation of monoculture communities, reducing native species diversity and posing threats to agriculture, human and animal health, and local ecosystems. Understanding its potential distribution patterns at a regional scale and its response to climate change is essential for effective monitoring, management, and control. In this study, we utilized the Maxent model to simulate potential habitat areas of P. americana across three timeframes (current, 2050s, and 2070s) under three climate change scenarios (SSP126, SSP245, and SSP585). Leveraging data from 556 P. americana sites across China, we employed ROC curves to assess the prediction accuracy. Our findings highlight key environmental factors influencing P. americana's geographical distribution, including the driest month's precipitation, the coldest month's minimum temperature, the wettest month's precipitation, isothermality, and temperature annual range. Under current climate conditions, P. americana potentially inhabits 280.26 × 104 km2 in China, with a concentration in 27 provinces and cities within the Yangtze River basin and its southern regions. While future climate change scenarios do not drastically alter the total suitable area, the proportions of high and low-suitability areas decrease over time, shifting towards moderate suitability. Specifically, in the SSP126 scenario, the centroid of the predicted suitable area shifts northeastward and then southwestward. In contrast, in the SSP245 and SSP585 scenarios, the centroid shifts northward.

12.
Bioresour Technol ; 393: 130029, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-37977495

RESUMO

The effects of biodegradable plastics of different thicknesses (30 and 40 µm) and sizes (20 × 20, 2 × 2, and 1 × 1 mm) on anaerobic digestion of food waste and digestate phytotoxicity were investigated. Methane productions (38 days) for the groups with 20 × 20, 2 × 2, and 1 × 1 mm of 30 µm plastics were 92.46, 138.27, and 259.95 mL/gVSremoval, respectively which are nearly 58 % higher than the control group (58.86 mL/gVSremoval). Methane production in 40 µm plastics groups was lower than in 30 µm groups of equal size. All sizes of 30 µm plastics promoted substrate hydrolysis, acidification, and relative abundance of key hydrolytic bacteria and methanogens. Phytotoxicity tests results showed that seed root elongation was inhibited in groups with 40 µm plastics. In conclusion, 30 µm biodegradable plastics were more suitable for anaerobic digestion with food waste than 40 µm.


Assuntos
Plásticos Biodegradáveis , Eliminação de Resíduos , Eliminação de Resíduos/métodos , Esgotos/microbiologia , Perda e Desperdício de Alimentos , Anaerobiose , Alimentos , Estudos de Viabilidade , Plásticos , Metano , Digestão , Reatores Biológicos
13.
Environ Technol ; 44(18): 2781-2794, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35188433

RESUMO

The addition of carbonaceous materials into anaerobic digestion (AD) has gained widespread attention due to their significant effects on anaerobic performance and antibiotic resistance gene (ARG) removal. This study selected graphite, graphene, and graphene oxide (GO) as additives to investigate variations in AD performance, ARG removal, microbial community diversity and structure in wet AD systems. The results indicated that the addition of graphite-based materials in wet AD systems could increase degradation of solid organic matters by 0.91%-3.41% and utilization of soluble organic fractions by 10.43%-13.67%, but could not stimulate methane production. After the addition of graphite and graphene, ARG removal rates were effectively increased to 90.85% and 94.22%, respectively. However, the total ARG removal rate was reduced to 77.46% with the addition of GO. In addition, the microbial diversity in the wet AD process was enhanced with the addition of GO only, graphite and graphene led to a reduction in it. As for bacterial community, graphite and graphene increased the abundance of Thermotogae from 43.43% to 57.42% and 58.74%, while GO increased the abundance of Firmicute from 49.90% to 56.27%. For the archaeal community, the proportion of hydrogenotrophic methanogens was improved when adding each graphite-based material; however, only GO increased Methanosaeta that was acetoclastic methanogens. Finally, methanogens were found as the ARG host, and ARGs that belong to the same subtype might exist in the same host bacteria.


Assuntos
Grafite , Microbiota , Anaerobiose , Antibacterianos/farmacologia , Bactérias/genética , Resistência Microbiana a Medicamentos/genética , Microbiota/genética , Metano
14.
RSC Adv ; 13(43): 30269-30272, 2023 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-37881211

RESUMO

Reported here is the efficient macrocyclization facilitated by skeleton preorganization. A pyridylcarbazole macrocycle and a phenylpyridylcarbazole macrocycle was synthesized in yield up to 75%. Single-crystal structures and theoretic computation uncovered that the skeleton preorganization promoted the formation of cyclization-favorable conformation of noncyclic precursors via π⋯π interactions. This result provided a new approach for the efficient syntheses of macrocycles.

15.
J Environ Public Health ; 2022: 1900301, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36225755

RESUMO

Aiming at the livelihood of fishermen under the fishing prohibition policy, quantitative research methods were used to explore the relationship between the willingness to quit fishing and livelihood capital. With reference to 609 survey data from 20 fishing grounds in 2 counties and cities of Hubei Province, this paper explores the necessity of convincing fishermen in the Yangtze River to quit fishing and evaluates the impact of livelihood mode on Honghu fishermen's willingness to quit fishing by means of structural equation model based on the sustainable livelihood framework developed by the UK Department for International Development. The results showed the following conclusions: (1) The proportion of fishermen who are willing to participate in quitting fishing is 66.7%, indicating that fishery production is still the main source of livelihood for many fishermen. The overall willingness of fishermen to quit fishing is strong, and fishermen have realized the importance of protecting fishery resources. (2) There is a strong correlation between the indicators of livelihood capital and the willingness of fishermen to quit fishing. Among them, the human capital has the most significant impact on fishermen's willingness to quit fishing for some compensation from public power. The research conclusion is helpful for the government to improve the fishing prohibition policy in a targeted manner and mobilize the enthusiasm of fishermen to protect fishery resources.


Assuntos
Pesqueiros , Caça , Cidades , Humanos , Inquéritos e Questionários
16.
Bioresour Technol ; 362: 127843, 2022 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-36031136

RESUMO

In the present study, a biochemical strategy for improving propionic acid production from kitchen waste acidification by bioaugmentation with Propionibacterium acidipropionici (P. acidipropionici) was investigated. When the inoculum of P. acidipropionici was 30% (w/w) of the seeding sludge, the propionic acid production increased by 79.57%. Further, bioaugmentation improved the relative abundance of Firmicute and Actinobacteria. The results of metagenomic analysis further reveal that the ATP-binding cassette (ABC) transporters and all related pathways of Propanoate metabolism (ko00640) were enriched when P. acidipropionici was added. For Propanoate metabolism, most functional genes involved in the conversion from Glycolysis / Gluconeogenesis (ko00010) to Propanoyl-CoA and conversion from Propanoyl-CoA to propionic acid were enhanced after bioaugmentation with P. acidipropionici, thereby promoting propionic acid production. As such, bioaugmentation with P. acidipropionici was effective in the anaerobic acidification of kitchen waste for propionic acid production.


Assuntos
Propionatos , Propionibacterium , Anaerobiose , Coenzima A/metabolismo , Concentração de Íons de Hidrogênio , Metagenômica , Propionatos/metabolismo , Propionibacteriaceae , Propionibacterium/genética , Propionibacterium/metabolismo
17.
Mamm Genome ; 21(7-8): 361-9, 2010 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-20686773

RESUMO

To date around 140 genetic alleles have been identified as being responsible for mouse cataract pathology, including Crya, Cryb, Cryg, Maf, Pax6, Pitx3, Sox, Connexins, MIP, and Lim-2. We obtained a dominant cataract mouse model from a spontaneous mutation in the F1 hybrids of outbred strain ICR mice crossed to the inbred strain BALB/cJ mice. Heterozygous and homozygous mutants expressed a nuclear cataract in both eyes. In 8-day-old mice, histological analysis showed that polygon epithelial cells were in the equatorial region and cortex underneath, and vacuole and sponge-like degeneration were in the cortical area underneath the posterior lens capsule. The nucleus of the lens was a deeply stained pink, with the shorter fibers losing their normal arrangement. For the entire eye, there was a blank zone in the equatorial region in 8-day-old mice; however, there was a certain degree of atrophy in cornea tension and retina in the lens in 3-month-old mice. The lens had been serious damaged in the homozygous mutants. For mutation mapping, heterozygous carriers were mated to wild-type C3H/HeJ mice, and offspring (F1 generation) with cataracts were backcrossed to the wild-type C3H/HeJ mice again. N2 mice with cataracts were used for genotyping. Using genome-wide linkage analysis, the mutation was mapped to chromosome 1 and the Cryg gene cluster between two markers was confirmed as the candidate gene. After direct sequencing the cDNA of the Cryg gene cluster, a 1-bp deletion was found in exon 3 of the Crygc gene, leading to a stop codon at the 76th amino acid of exon 3 which results in production of a truncated protein in mutant mice (Leu160Stop). Bioinformatic analysis of the mutant gammaC-crystallin reveals that the COOH-terminal of the mutant protein deletes a beta-sheet, which affects the function of the lens proteins and leads to the development of cataracts.


Assuntos
Pareamento Incorreto de Bases , Catarata/genética , gama-Cristalinas/genética , Animais , Pareamento Incorreto de Bases/fisiologia , Catarata/patologia , Feminino , Genes Dominantes , Ligação Genética , Cristalino/patologia , Masculino , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C3H , Camundongos Endogâmicos ICR , Camundongos Mutantes , Análise de Sequência de DNA , Deleção de Sequência/fisiologia
18.
Chemosphere ; 256: 127101, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32450355

RESUMO

Previous studies of the dynamics of sulfate-reducing bacteria (SRB) and sulfur-oxidizing bacteria (SOB) have focused on deep stratified lakes. The objective of this study is to present an in-depth investigation of the structure and dynamics of sulfur bacteria (including SRB and SOB) in the water column of shallow freshwater lakes. A cyanobacterial bloom biomass (CBB)-amended mesocosm experiment was conducted in this study, in which water was taken from a shallow eutrophic lake with sulfate levels near 40 mg L-1. Illumina sequencing was used to investigate SRB and SOB species involved in CBB decomposition and the effects of the increases in sulfate input on the water column microbial community structure. The accumulation of dissolved sulfide (∑H2S) produced by SRB during CBB decomposition stimulated the growth of SOB, and ∑H2S was then oxidized back to sulfate by SOB in the water column. Chlorobaculum sequences (the main SOB species in the study) were significantly influenced by increases in sulfate input, with relative abundance increasing approximately four-fold in treatments amended with 40 mg L-1 sulfate (referred to as 40S) when compared to the treatment without additional sulfate addition (referred to as CU). Additionally, an increase in SOB number was observed from day 26-37, concurrent with the decrease in SRB number, indicating the succession of sulfur bacteria. These findings suggest that biological sulfur oxidation and succession of sulfur bacteria occur in the water column during CBB decomposition in shallow freshwater ecosystems, and the increases in sulfate input stimulate microbial sulfur oxidation.


Assuntos
Cianobactérias/crescimento & desenvolvimento , Lagos/microbiologia , Biomassa , Chlorobi , Ecossistema , Oxirredução , Sulfatos , Sulfetos , Enxofre/química
19.
Front Microbiol ; 10: 2958, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-32010075

RESUMO

Cycloaddition reactions such as intramolecular Diels-Alder (IMDA) are extremely important in constructing multicyclic scaffolds with diverse bioactivities. Using MycB as a biomarker, three new polyketides - Chaetolivacines A (1), B (3), and C (4) - with one known compound Myceliothermophin E (2) comprising of decalin and 4-hydroxy-2-pyridones were obtained from the culture of Chaetomium olivaceum SD-80A under the guidance of gene mining. The structures of these compounds were established using detailed 1D, 2D NMR, and high-resolution electron spray ionization mass spectroscopy (HRESIMS) analysis. The relative and absolute configurations of the compounds 1, 3, and 4 were elucidated by NOESY and ECD. The biosynthesis pathways of these compounds were proposed, which involves in three key genes ChaA [polyketide synthase-non-ribosomal peptide synthetases (PKS-NRPS)], ChaB, and ChaC. Compounds 1-4 were tested for their antimicrobial activities, and compounds 2 and 3 showed moderate bioactivity against Staphylococcus aureus (SA) and methicillin-resistant S. aureus (MRSA) with MIC values of 15.8 and 27.1 µM. The results showed that configuration of C-21 in 3 and 4 is important for anti-SA and anti-MRSA activities. This study reveals the significant potential of the genus Chaetomium in producing new PKS-NRPS, therefore increasing the speed in the mining for new sources of antimicrobial agents.

20.
Dent Mater J ; 37(5): 717-724, 2018 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-29998939

RESUMO

This study evaluated surface gloss, roughness and color change of six current flowable composites after simulated toothbrushing, including four traditional flowable composites (i.e. GrandioSO Flow, Arabesk Flow, Kerr Revolution Formula 2 and Gradia Direct LoFlo), one self-adhering flowable composite (Kerr Vertise Flow) and one universal injectable composite (G-ænial Universal Flo). Forty-eight dimensionally standardized specimens (n=8/group) were made from six composites. Before and after 1 h toothbrushing simulation, surface gloss was measured with a glossmeter, and surface roughness was evaluated with a profilometer, and color was measured with a spectrophotometer. In this study, G-ænial Universal Flo, termed as universal injectable composite by the manufacturer, presented excellent surface properties after toothbrush abrasion; Gradia Direct LoFlo showed excellent color stablity after toothbrush abrasion; color alteration of composites caused by toothbrush abrasion was acceptable on the premise that 3.3∆E units were considered as acceptable threshold values.


Assuntos
Cor , Resinas Compostas/química , Escovação Dentária , Adesivos Dentinários , Teste de Materiais , Espectrofotometria , Propriedades de Superfície
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