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1.
Chemosphere ; 354: 141739, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38503383

RESUMO

Considering the persistent and covert nature of heavy metal soil contamination, the sustainable development of ecological environments and food safety is at significant risk. Our study focuses on remediating soils contaminated with chromium (Cr); we introduce an advanced remediation material, iron oxide phosphoric acid-loaded activated biochar (HFBC), synthesized through pyrolysis. This HFBC displays greater microporosity, fewer impurities, and enhanced efficiency for the remediation process. Our research utilized a comprehensive set of analytical techniques, including Scanning Electron Microscopy (SEM), Fourier Transform Infrared Spectroscopy (FTIR), and X-ray Photoelectron Spectroscopy (XPS), alongside adsorption studies to elucidate the Cr removal mechanism. The effectiveness of HFBC in remediation was influenced by several factors: the pH level, dosage of HFBC, the initial concentration of Cr, and the ambient temperature. Our results indicated an optimal chromium (VI) adsorption capacity of 55.5 mg/g by HFBC at a pH of 6.0 and a temperature of 25 °C, with the process adhering to the pseudo-second-order kinetic model and the Langmuir adsorption isotherm, thus suggesting spontaneity in the uptake method. Moreover, this mechanism encompasses both adsorption and reduction reactions. Using HFBC in pot experiments with cabbage indicated not only an increase in soil pH and cation exchange capacity (CEC), but also a surge in bacterial community abundance. Significant reductions in bioavailable chromium were also recorded. Interestingly, HFBC addition bolstered the growth of cabbage, while concurrently diminishing chromium accumulation within the plant, particularly notable as the HFBC application rate increased. In summation, the HFBC produced in our study has demonstrated convincing efficacy in removing chromium from aqueous solutions and soil. Moreover, the positive agronomic implications of its use, such as enhanced plant growth and reduced heavy metal uptake by plants, indicate its high potential for operational value in the domain of environmental remediation of heavy metals.


Assuntos
Cloretos , Compostos Férricos , Ácidos Fosfóricos , Typhaceae , Poluentes Químicos da Água , Água , Solo/química , Cromo/química , Carvão Vegetal/química , Adsorção , Poluentes Químicos da Água/análise , Cinética
2.
Int J Mol Sci ; 25(5)2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38473796

RESUMO

Histones are the core components of the eukaryote chromosome, and have been implicated in transcriptional gene regulation. There are three major isoforms of histone H3 in Arabidopsis. Studies have shown that the H3.3 variant is pivotal in modulating nucleosome structure and gene transcription. However, the function of H3.3 during development remains to be further investigated in plants. In this study, we disrupted all three H3.3 genes in Arabidopsis. Two triple mutants, h3.3cr-4 and h3.3cr-5, were created by the CRISPR/Cas9 system. The mutant plants displayed smaller rosettes and decreased fertility. The stunted growth of h3.3cr-4 may result from reduced expression of cell cycle regulators. The shorter stamen filaments, but not the fertile ability of the gametophytes, resulted in reduced fertility of h3.3cr-4. The transcriptome analysis suggested that the reduced filament elongation of h3.3cr-4 was probably caused by the ectopic expression of several JASMONATE-ZIM DOMAIN (JAZ) genes, which are the key repressors of the signaling pathway of the phytohormone jasmonic acid (JA). These observations suggest that the histone variant H3.3 promotes plant growth, including rosette growth and filament elongation.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/genética , Histonas/metabolismo , Proteínas de Arabidopsis/genética , Fatores de Transcrição/metabolismo , Reguladores de Crescimento de Plantas/metabolismo
3.
BMC Genomics ; 25(1): 136, 2024 Feb 02.
Artigo em Inglês | MEDLINE | ID: mdl-38308218

RESUMO

Microbial remediation of heavy metal polluted environment is ecofriendly and cost effective. Therefore, in the present study, Shewanella putrefaciens stain 4H was previously isolated by our group from the activated sludge of secondary sedimentation tank in a dyeing wastewater treatment plant. The bacterium was able to reduce chromate effectively. The strains showed significant ability to reduce Cr(VI) in the pH range of 8.0 to 10.0 (optimum pH 9.0) and 25-42 ℃ (optimum 30 ℃) and were able to reduce 300 mg/L of Cr(VI) in 72 h under parthenogenetic anaerobic conditions. In this paper, the complete genome sequence was obtained by Nanopore sequencing technology and analyzed chromium metabolism-related genes by comparative genomics The genomic sequence of S. putrefaciens 4H has a length of 4,631,110 bp with a G + C content of 44.66% and contains 4015 protein-coding genes and 3223,  2414, 2343 genes were correspondingly annotated into the COG, KEGG, and GO databases. The qRT-PCR analysis showed that the expression of chrA, mtrC, and undA genes was up-regulated under Cr(VI) stress. This study explores the Chromium Metabolism-Related Genes of S. putrefaciens 4H and will help to deepen our understanding of the mechanisms of Cr(VI) tolerance and reduction in this strain, thus contributing to the better application of S. putrefaciens 4H in the field of remediation of chromium-contaminated environments.


Assuntos
Shewanella putrefaciens , Shewanella putrefaciens/genética , Shewanella putrefaciens/metabolismo , Oxirredução , Cromo/toxicidade , Cromo/metabolismo , Bactérias/metabolismo
4.
Environ Sci Pollut Res Int ; 30(53): 113323-113334, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37848784

RESUMO

Significant global efforts are currently underway to alleviate the presence of toxic metals in water bodies, aiming to encourage a sustainable environment. Nevertheless, the scientific community has yet to methodically inspect the performance and mechanisms underlying the interaction between nanomaterials and microorganisms in this context. Therefore, this study seeks to address this knowledge gap by developing a novel system that integrates nano zero-valent iron (nZVI) with chromium-reducing bacteria (CrRB) to efficiently remove Cr(VI) from water sources. The combined use of RBC600 and CrRB resulted in a Cr(VI) removal rate of 77.73%, displaying a substantial improvement of 17.61% compared to the use of CrRB alone. The efficacy of Cr(VI) elimination was observed to be affected by several factors within the system, such as the pH value, the quantity of nZVI added, the degree of CrRB inoculation, and the initial concentration of Cr(VI) at the onset of the experiment. When the pH was adjusted to 5, the complete removal of 200 mg/L Cr(VI) was achieved within 36 h. Increasing the dosage of nZVI to above 2 g/L resulted in the complete elimination of Cr(VI) from the solution within 72 h. This can be attributed to the availability of more reaction sites for the reduction of Cr(VI), facilitated by the higher nZVI dose. Additionally, the increased dose of nZVI allowed for the dissolution of more reactive Fe(II) ions. The characterization analysis, high-throughput sequencing, and fluorescence quantitative PCR results have established that CrRB and its extracellular polymer effectively reduce and complex Cr(VI). This process facilitated the dissolution of the passivated layer on the surface of nZVI, thus significantly enhancing the efficiency of nZVI in responding to Cr(VI). Additionally, the presence of nZVI created a favorable living environment for CrRB, resulting in increased richness and diversity within the CrRB community. These findings provide valuable preliminary insights into the mechanism underlying Cr(VI) elimination by the synergistic interaction between nZVI and CrRB. Therefore, this study establishes a solid theoretical foundations for the application of nano-bio synergy in the remediation of Cr(VI).


Assuntos
Ferro , Poluentes Químicos da Água , Ferro/química , Águas Residuárias , Poluentes Químicos da Água/análise , Cromo/química , Água/química , Adsorção
5.
Environ Res ; 225: 115588, 2023 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-36858301

RESUMO

The removal of Cr(VI) and As(V) from aqueous solutions has been a worldwide concern. In this study, Typha biochar (FBC) with magnetic iron oxide was prepared by impregnating Typha with FeCl3 and performing pyrolysis, and the possible mechanism of Cr(VI) and As(V) removal was investigated by combining characterization means and adsorption experiments. The results showed that the modified Typha biochar is rich in pores and has the potential to eliminate Cr and As through processes such as exchange and reduction. The single molecule uptake capacities of FBC for Cr(VI) and As(V) were 32.82 and 21.56 mg g-1, respectively. The adsorption process is spontaneous heat absorption, and the adsorption results are also consistent with the proposed secondary kinetic model. FBC still had >60% removal efficiency in the second and third reuse of Cr(VI), indicating its good recyclability. Therefore, this study confirms that FBC can effectively remove both Cr(VI) and As(V).


Assuntos
Typhaceae , Poluentes Químicos da Água , Compostos Férricos , Cromo , Carvão Vegetal , Adsorção , Poluentes Químicos da Água/análise
6.
Nanomaterials (Basel) ; 13(4)2023 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-36839013

RESUMO

The heat released from an aluminum-air battery has a great effect on its performance and operating life during the discharge process. A theoretical model was proposed to evaluate the resulting thermal effect, and the generated heat was divided into the following sources: anodic aluminum oxidation reaction, cathodic oxygen reduction reaction, heat production against the battery internal resistance, and hydrogen-evolution reaction. Quantitative analysis was conducted on each part, showing that all heat production sources increased with discharge current density. It should be noted that the heat caused by hydrogen evolution accounted for the most, up to 90%. Furthermore, the regulation strategy for inhibiting hydrogen evolution was developed by addition of hybrid additives to the electrolyte, and the hydrogen-evolution rate was greatly reduced by more than 50% as was the generated heat. This research has important guidance for the thermal effect analysis of aluminum-air batteries, together with control of the thermal management process by inhibiting hydrogen evolution, thus promoting their practical application.

7.
Nanomaterials (Basel) ; 12(19)2022 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-36234667

RESUMO

Biochar/nano-zero-valent iron (BC-nZVI) composites are currently of great interest as an efficient remediation material for contaminated soil, but their potential to remediate Cr-contaminated soils and effect on soil microecology is unclear. The purpose of this study was to investigate the effect of BC-nZVI composites on the removal of Cr(VI) from soil, and indigenous microbial diversity and community composition. The results showed that after 15 days of remediation with 10 g/kg of BC-nZVI, 86.55% of Cr(VI) was removed from the soil. The remediation of the Cr-contaminated soil with BC-nZVI resulted in a significant increase in OTUs and α-diversity index, and even a significant increase in the abundance and diversity of indigenous bacteria and unique bacterial species in the community by reducing the toxic concentration of Cr, changing soil properties, and providing habitat for survival. These results confirm that BC-nZVI is effective in removing Cr(VI) and stabilizing Cr in soil with no significant adverse effects on soil quality or soil microorganisms.

8.
Front Plant Sci ; 13: 983460, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36110360

RESUMO

Plants must reprogram gene expression to adapt constantly changing environmental temperatures. With the increased occurrence of extremely low temperatures, the negative effects on plants, especially on growth and development, from cold stress are becoming more and more serious. In this research, strand-specific RNA sequencing (ssRNA-seq) was used to explore the dynamic changes in the transcriptome landscape of Arabidopsis thaliana exposed to cold temperatures (4°C) at different times. In total, 7,623 differentially expressed genes (DEGs) exhibited dynamic temporal changes during the cold treatments. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment analysis showed that the DEGs were enriched in cold response, secondary metabolic processes, photosynthesis, glucosinolate biosynthesis, and plant hormone signal transduction pathways. Meanwhile, long non-coding RNAs (lncRNAs) were identified after the assembly of the transcripts, from which 247 differentially expressed lncRNAs (DElncRNAs) and their potential target genes were predicted. 3,621 differentially alternatively spliced (DAS) genes related to RNA splicing and spliceosome were identified, indicating enhanced transcriptome complexity due to the alternative splicing (AS) in the cold. In addition, 739 cold-regulated transcription factors (TFs) belonging to 52 gene families were identified as well. This research analyzed the dynamic changes of the transcriptome landscape in response to cold stress, which reveals more complete transcriptional patterns during short- and long-term cold treatment and provides new insights into functional studies of that how plants are affected by cold stress.

9.
J Gastrointest Oncol ; 13(3): 1255-1265, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35837205

RESUMO

Background: To clarify the molecular mechanism of hepatocellular carcinoma (HCC), conducive to developing an effective HCC therapy. Owing to the severe drug resistance, the clinical use of sorafenib, which is approved for HCC treatment, is limited. The precise molecular mechanisms of sorafenib drug resistance remain unclear. In the current work, we evaluated the role of Obg-like ATPase 1 (OLA1) in sorafenib resistance in HCC. Methods: The survival of HCC patients between OLA1 expression and sorafenib treatment was analyzed by Kaplan-Meier plotter. Cell viability was measured by cell counting kit-8 (CCK-8) and colony formation assays. Cell death was detected by propidium iodide (PI) and trypan blue staining. The mRNA and protein levels were measured by real-time quantitative polymerase chain reaction (RT-qPCR) and western blot (WB), respectively. Results: We found that OLA1 was highly correlated with sorafenib resistance of HCC through a public database. Further study showed that knockdown of OLA1 enhanced cell proliferation inhibition and cell death induced by sorafenib, along with a reduction of proliferation-associated proteins (c-Myc and cyclin D1) and increase of apoptosis-related proteins (cleaved caspase-3 and cleaved PARP) in HCC cells. In addition, knockdown of OLA1 reduced the activation of glycogen synthase kinase 3ß (GSK-3ß)/ß-catenin. Conclusions: Our results proved that OLA1 can be a potential target to enhance sorafenib sensitivity in HCC.

10.
Acta Chim Slov ; 68(4): 804-810, 2021 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-34918762

RESUMO

A new dinuclear copper(II) complex [Cu2(µ-Br)2L2]·0.5MeOH with the benzohydrazone ligand 4-bromo-N'-(1-(pyridin-2-yl)ethylidene)benzohydrazide (HL) has been synthesized and characterized by elemental analysis, IR and UV-Vis spectroscopic studies. Single crystal structures of the complex and the benzohydrazone compound were studied. The Cu atoms in the complex are coordinated by two benzohydrazone ligands and two Br bridging groups, forming square pyramidal coordination. The complex has good inhibitory activity on Jack bean urease, with IC50 value of 1.38 µmol·L-1.


Assuntos
Complexos de Coordenação/síntese química , Cobre/química , Inibidores Enzimáticos/química , Hidrazinas/química , Urease/antagonistas & inibidores , Sítios de Ligação , Canavalia/enzimologia , Complexos de Coordenação/química , Complexos de Coordenação/metabolismo , Cristalografia por Raios X , Inibidores Enzimáticos/síntese química , Inibidores Enzimáticos/metabolismo , Hidrazinas/síntese química , Concentração Inibidora 50 , Conformação Molecular , Simulação de Acoplamento Molecular , Urease/metabolismo
11.
Zhongguo Zhong Yao Za Zhi ; 46(19): 5015-5019, 2021 Oct.
Artigo em Chinês | MEDLINE | ID: mdl-34738396

RESUMO

Five monoterpenoid compounds(1-5) were isolated and purified from the acetone fraction of the aqueous extract of Zingiberis Rhizoma Recens by MCI, Sephadex LH-20, silica gel, semi-preparative HPLC, and TLC. Their structures were identified with multiple spectroscopical methods including 1 D-NMR, 2 D-NMR, and MS. The five compounds were identified as(2E,6Z)-8-hydroxy-2,6-dimethylocta-2,6-dien-1-yl-(E)-3-(4-hydroxy-3-methoxyphenyl) acrylate(1),(2E,6E)-8-hydroxy-3,7-dimethylocta-2,6-die-noic acid(2),(E)-1,8-dihydroxy-3,7-dimethyl-2-octenoic acid(3), linalyl-ß-D-glucopyranoside(4), and ß-D-glucopyranoside-(2E)-3,7-dimethyl-2,6-octadien-1-yl(5), respectively.Compound 1 was a new monoterpene ester, and compounds 4-5 were isolated from this plant for the first time.


Assuntos
Ésteres , Monoterpenos , Cromatografia Líquida de Alta Pressão , Rizoma
12.
Nanomaterials (Basel) ; 11(10)2021 Oct 13.
Artigo em Inglês | MEDLINE | ID: mdl-34685145

RESUMO

In this study, ramie biochar (RBC) was used to activate nano zero-valent iron (nZVI) to enhance hexavalent chromium (Cr(VI)) removal. The best results were obtained at a pyrolysis temperature of 600 °C, a biochar particle size of < 150 µm, and an iron to carbon ratio = 1:1. Under the optimal conditions, the removal of Cr(VI) by RBC600-nZVI (98.69%) was much greater than that of RBC600 (12.42%) and nZVI (58.26%). Scanning electron microscopy (SEM), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and X-ray photoelectron spectroscopy (XPS) revealed that the reaction mechanism at the Fe and Cr interface was a multiple interaction mechanism with reduction dominated, adsorption, and co-precipitation simultaneously. The enhanced performance of RBC600-nZVI resulted from the effective dispersion of nZVI on the surface of RBC600, therefore increasing the adsorption activity sites. At the same time, RBC600 and nZVI exerted a synergistic influence on the composite structure, which jointly promoted the reduction reaction of Cr(VI) and removed more Cr(VI). This study shows that RBC-nZVI is a potentially valuable remediation material that not only provides a new idea for the utilization of ramie waste, but also effectively overcomes the limitations of nZVI, thus, achieving efficient and rapid remediation of Cr(VI).

13.
Transp Res E Logist Transp Rev ; 141: 102010, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32834741

RESUMO

Motivated by United Nations' Sustainable Development Goals (SDGs) and the importance of sustainability, this study examines how the textile and apparel (TA) supply chains can comply with the SDGs. By examining the literature as well as industrial practices, we show that the current sustainable operations in TA industry are far away from realizing the goals of economic growth going hand-in-hand with the social and environmental sustainability. For instance, among the SDGs, the goals of "Responsible Consumption and Production", "Clean Water and Sanitation", and "Climate Action" receive a considerable amount of attention, while goals of "No Poverty", "Reduced Inequalities", "Life below Water" and "Life on Land" have the least attention. Balanced sustainable development actions from the stakeholders' perspective are proposed. Managerial implications and future studies are discussed.

14.
Acta Chim Slov ; 67(3): 896-903, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-33533413

RESUMO

Two new ethyl maltolato coordinated mononuclear oxidovanadium(V) complexes [VOLa(emt)]·DMF (1) and [VOLb(emt)] (2), where H2La = N'-(4-bromo-2-hydroxybenzylidene)-3-hydroxybenzohydrazide, H2Lb = N'-(4-bromo-2-hydroxybenzylidene)benzohydrazide, Hemt = ethyl maltol, have been synthesized and characterized on the basis of CHN elemental analysis, FT-IR and UV-Vis spectroscopy and powder XRD analysis. Structures of the complexes were further characterized by single crystal X-ray diffraction, which indicated that the V atoms in the complexes adopt octahedral coordination. The hydrazones behave as NOO tridentate ligands. The catalytic epoxidation properties on cyclooctene of the complexes were investigated.

15.
Opt Express ; 24(15): 16630-7, 2016 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-27464117

RESUMO

We present an all-fiber all-polarization-maintaining (PM) single mode (SM) fiber pulse nonlinear amplification system. The seed laser with a repetition rate of 200 MHz is amplified by two-section erbium-doped PM gain fibers with different peak-absorption rate. The amplified pulse duration can be compressed into 34-fs with 320-mW output power, which corresponds to 1.6-nJ pulse energy and approximate 23.5-kW peak power. In addition, the amplified and compressed pulse is further coupled into the high nonlinear fiber and an octave-spanning supercontinuum generation can be obtained. To the best of our knowledge, it is the highest peak power and the shortest pulse duration obtained in the field of all-fiber all-PM SM pulse-amplification systems.

16.
Mol Biol Rep ; 41(2): 901-7, 2014 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-24385297

RESUMO

MicroRNAs (miRNAs) are 20-24 nucleotide long non-coding RNAs that play critical regulatory roles during plant development, organ morphogenesis, and cell fate determination and differentiation. In this study, miRNA microarray chips were used to explore the expression profile of ramie miRNAs between the bast of fiber elongation phase and those of cell wall thickening and end wall dissolving phase. There are 150 and 148 credible miRNAs in the bast of fiber elongation phase and cell wall thickening and end wall dissolving phase, respectively. These miRNAs distributed in 27 species and mainly concentrated in nine species. Analysis showed that 51 miRNAs were differentially expressed: 27 up-regulated (miR166, miR172, miR396, miR482, miR894 and miR2911 families) and 24 down-regulated (miR156, miR159, miR164, miR319 and miR1450 families) in the bast of fiber elongation phase compared with the bast of cell wall thickening and end wall dissolving phase. To further confirm our results, we examined the expression of three miRNAs (zma-miR172b*, pvu-miR482 and vvi-172a) by quantitative real-time reverse transcriptase-PCR. Our results will provide a molecular basis for future research miRNA function on ramie genetics and breeding.


Assuntos
Boehmeria/genética , MicroRNAs/biossíntese , RNA de Plantas/genética , Estresse Fisiológico , Boehmeria/crescimento & desenvolvimento , Parede Celular/genética , Regulação da Expressão Gênica de Plantas , MicroRNAs/genética , Análise de Sequência com Séries de Oligonucleotídeos , RNA de Plantas/biossíntese , Transcriptoma
17.
Wei Sheng Wu Xue Bao ; 48(5): 602-7, 2008 May.
Artigo em Chinês | MEDLINE | ID: mdl-18652291

RESUMO

OBJECTIVE: Bacillus sphaericus is unable to use hexose and pentoses as the sole carbon source, due to the lack of key enzymes in Embden-Meyerhof-Parnas pathway (EMP), Hexose Monophophate Pathway (HMP) and Entner-Doudoroff (ED) pathway, such as phosphofructokinase (PFK). Based on the genome sequence annotation results of B. sphaericus C3-41, the phosphofructokinase gene pfk was verified with a single copy on chromosome, the aim of this research is to analysis the EMP pathway in B. sphaericus further, and confirm the function of phosphofructokinase. METHODS: The methods of southern-blot of pfk gene among different B. sphaericus strains, pfk ORF cloning from C3-41 and expressing in Escherichia coli, the corresponding sequence analysis and anlignment were used. RESULTS: The pfk ORF of B. sphaericus was composed of 960 bp nucleitides encoding a protein about 42 kDa, and the PFK sequence analysis showed it had the conservative amino acids-binding sites and an ATP-binding domain. The expression of pfk in recombinant E. coli strain could complement the PFK activity of a pfk mutated E. coli strain DF1020. CONCLUSION: The expressed PFK had the conventional phosphofructokinase activity, and settled the foundation for the further research of catabolism of B. sphaericus.


Assuntos
Bacillus/enzimologia , Fosfofrutoquinases/genética , Fosfofrutoquinases/metabolismo , Trifosfato de Adenosina/metabolismo , Sequência de Aminoácidos , Clonagem Molecular , Biologia Computacional , Sequência Conservada , Escherichia coli/genética , Dosagem de Genes , Expressão Gênica , Dados de Sequência Molecular , Fases de Leitura Aberta , Fosfofrutoquinases/química , Fosfofrutoquinases/isolamento & purificação , Alinhamento de Sequência
18.
Appl Environ Microbiol ; 73(23): 7744-6, 2007 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-17933917

RESUMO

Expression of a chitinase gene, chiAC, from Bacillus thuringiensis in B. sphaericus 2297 using the binary toxin promoter yielded a recombinant strain that was 4,297-fold more toxic than strain 2297 against resistant Culex quinquefasciatus. These results show that this chitinase can synergize the toxicity of the binary toxin against mosquitoes and thus may be useful in managing mosquito resistance to B. sphaericus.


Assuntos
Bacillus/metabolismo , Quitinases/metabolismo , Culex/microbiologia , Controle Biológico de Vetores/métodos , Animais , Bacillus/genética , Quitinases/genética , Cinética , Regiões Promotoras Genéticas/genética , Proteínas Recombinantes de Fusão/genética , Proteínas Recombinantes de Fusão/metabolismo
19.
Wei Sheng Wu Xue Bao ; 47(3): 392-5, 2007 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-17672293

RESUMO

Bacillus thuringiensis is a member of the B. cereus group, which also contains B. cereus, B. mycoides, B. pseudomycoides , B. anthracis and B. weihenstephanensis. Among them, B. thuringiensis and B. cereus share a high level chromosomal similarity and are phenotypically similar except that B. thuringiensis has insecticidal plasmid encoding crystal proteins. Twenty-six B. cereus group strains were surveyed in this study for the presence of enterotoxin genes and other toxin genes related to pathogenicity. PCR results showed that the pleiotropic virulence regulator plcR was presented in 17 B. cereus group strains. About 73% of the B. cereus group strains and 83% of the B. thuringiensis strains contained at least one of the three hbl genes and one of the three nhe genes, indicating that B. thuringiensis, including strains used commercially, had enterotoxin encoding genes. Additionally, B. cereus DBt248 was proved to be devoid of all three hbl genes, three nhe genes or plcR. Thus this strain might be a potential candidate as a host strain for expressing B. thuringiensis crystal toxins to construct safety insecticidal engineering strains without enterotoxic activity.


Assuntos
Bacillus cereus/genética , Bacillus cereus/patogenicidade , Proteínas de Bactérias/genética , Enterotoxinas/genética , Proteínas Hemolisinas/genética , Fatores de Virulência/genética , Bacillus/genética , Bacillus/metabolismo , Bacillus/patogenicidade , Bacillus cereus/metabolismo , Proteínas de Bactérias/metabolismo , Enterotoxinas/metabolismo , Proteínas Hemolisinas/metabolismo , Dados de Sequência Molecular , Fatores de Virulência/metabolismo
20.
Wei Sheng Wu Xue Bao ; 47(3): 456-60, 2007 Jun.
Artigo em Chinês | MEDLINE | ID: mdl-17672305

RESUMO

Mosquitocidal toxin 1 (Mtx1) was synthesized during vegetative phase of Bacillus sphaericus and it had been proved to have higher activity to Aedes spp. larvae and Binary toxin (Bin) resistance Culex larvae. The truncated 97 kDa Mtx1 with a deletion of the signal peptide and the Cyt1 Aa crystal protein, a 27.3 kDa delta-endotoxin from Bacillus thuringiensis subsp. israelensis (Bti), were purified from Escherichia coli and B. thuringiensis recombinant strains respectively. Both purified toxins had high toxicity against Culex quinquefasciatus larvae. Bioassay result revealed the purified Mtx1 toxin had high toxicity against the target mosquito larvae, with LCso of 45.2 ng/mL. However, the mixture of Mtx1 and Cytl Aa exhibited higher toxicity against the mosquito larvae, with a lowest LC50 value of 20.19 ng/mL at the ratio of 1:3. (Mtx1:Cyt1 Aa). The calculated synergistic factor of different mixtures suggested a strong synergistic effect between Cyt1 Aa toxin and Mtx1. Furthermore, the presence of Cyt1Aa in the mixture could induce early larval mortality, enhancing the activity of Mtx1 to the target mosquito larvae. The synergistic effect of Cyt1 Aa on mortality of Mtx1 to mosquito larvae might be caused by the damage of the larval midgut-hemocoel barrier induced by the activated CytlAa toxin, which enhanced the specific pathogenesis of Mtx1 on mosquito larvae. It is suggested that the co-application of Mtx1 and Cyt1 Aa in future will be integrated for mosquito management.


Assuntos
Proteínas de Bactérias/farmacologia , Toxinas Bacterianas/farmacologia , Culex/efeitos dos fármacos , Endotoxinas/farmacologia , Proteínas Hemolisinas/farmacologia , Inseticidas/farmacologia , Animais , Toxinas de Bacillus thuringiensis , Proteínas de Bactérias/genética , Proteínas de Bactérias/isolamento & purificação , Proteínas de Bactérias/metabolismo , Toxinas Bacterianas/genética , Toxinas Bacterianas/isolamento & purificação , Toxinas Bacterianas/metabolismo , Sinergismo Farmacológico , Endotoxinas/genética , Endotoxinas/isolamento & purificação , Endotoxinas/metabolismo , Proteínas Hemolisinas/genética , Proteínas Hemolisinas/isolamento & purificação , Proteínas Hemolisinas/metabolismo , Inseticidas/metabolismo , Larva/efeitos dos fármacos
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