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1.
Inflammopharmacology ; 27(4): 809-816, 2019 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-29943151

RESUMO

BACKGROUND: The study was conducted to scrutinize the outcome of isoliquiritigenin (ISL) against cerebral injury in septic mice. METHODS: The sepsis was introduced using cecal ligation and puncture (CLP) method in experimental mice. The effect of ISL was quantified using the content of brain water and blood brain barrier (BBB) permeability. The effect on the levels of myeloperoxidase (MPO), superoxide dismutase (SOD), malondialdehyde (MDA) and glutathione (GSH) in brain homogenates was also determined. The effect of ISL on the levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, and IL-6 in serum was also estimated. The levels of various inflammatory biomarkers (COX-2 and PGE2) were also studied. The expression of NF-κB signalling cascade and inducible nitric oxide synthase (iNOS) was estimated by Western blot. RESULTS: Compared with CLP group, the brain water content was found to be reduced significantly together with the enhanced BBB integrity in ISL treated group. The level of MDA was reduced together with enhanced level of SOD and GSH in the ISL treated group. The levels of TNF-α, IL-1ß, and IL-6 were also found to be modulated in ISL group. The level of COX-2 and PGE2 was reduced to near normal after ISL administration together with increase in the IκBα expression and reduction of p65 and p-p65 expression in a concentration-dependent manner. The expression of iNOS was also found to be reduced in ISL group. CONCLUSION: These results demonstrate that ISL causes protection of CLP-induced sepsis in experimental mice via multiple pathways.


Assuntos
Lesões Encefálicas/tratamento farmacológico , Chalconas/farmacologia , NF-kappa B/metabolismo , Substâncias Protetoras/farmacologia , Sepse/tratamento farmacológico , Animais , Biomarcadores/metabolismo , Lesões Encefálicas/metabolismo , Modelos Animais de Doenças , Glutationa/metabolismo , Inflamação/tratamento farmacológico , Inflamação/metabolismo , Interleucina-1beta/metabolismo , Interleucina-6/metabolismo , Masculino , Malondialdeído/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico Sintase Tipo II/metabolismo , Estresse Oxidativo/efeitos dos fármacos , Sepse/metabolismo , Transdução de Sinais/efeitos dos fármacos , Superóxido Dismutase/metabolismo , Fator de Necrose Tumoral alfa/metabolismo
2.
Biotechnol Lett ; 40(2): 349-358, 2018 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-29124518

RESUMO

OBJECTIVES: To investigate the efficiency of a new cascade biocatalysis system for the conversion of R, S-ß-amino alcohols to enantiopure vicinal diol and ß-amino alcohol. RESULTS: An efficient cascade biocatalysis was achieved by combination of a transaminase, a carbonyl reductase and a cofactor regeneration system. An ee value of > 99% for 2-amino-2-phenylethanol and 1-phenyl-1, 2-ethanediol were simultaneously obtained with 50% conversion from R, S-2-amino-2-phenylethanol. The generality of the cascade biocatalysis was further demonstrated with the whole-cell approaches to convert 10-60 mM R, S-ß-amino alcohol to (R)- and (S)-diol and (R)- and (S)-ß-amino alcohol in 90-99% ee with 50-52% conversion. Preparative biotransformation was demonstrated at a 50 ml scale with mixed recombinant cells to give both (R)- and (S)-2-amino-2-phenylethanol and (R)- and (S)-1-phenyl-1, 2-ethanediol in > 99% ee and 40-42% isolated yield from racemic 2-amino-2-phenylethanol. CONCLUSIONS: This cascade biocatalysis system provides a new practical method for the simultaneous synthesis of optically pure vicinal diol and an ß-amino alcohol.


Assuntos
Oxirredutases do Álcool/metabolismo , Amino Álcoois/química , Amino Álcoois/metabolismo , Biotecnologia/métodos , Amino Álcoois/análise , Proteínas de Bactérias/metabolismo , Biocatálise , Sistema Livre de Células , Escherichia coli/enzimologia , Estereoisomerismo , Transaminases/metabolismo
3.
Pest Manag Sci ; 2024 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-39319635

RESUMO

BACKGROUND: Paracoccus marginatus has invaded many countries, spreading rapidly and causing significant economic losses to crops. Accurate detection during the monitoring process is critical to prevent its expansion into new areas, therefore it is necessary to develop efficient and reliable detection methods. Traditional detection methods are time-consuming and instrument-dependent owing to the morphological similarities and small sizes of P. marginatus and other mealybugs, therefore establishing an efficient, rapid, and sensitive method for field detection in resource-limited settings is critical. RESULTS: A sensitive and rapid detection system was developed to detect P. marginatus using recombinase polymerase amplification (RPA) combined with clustered regularly interspaced short palindromic repeats (CRISPR)/Cas12a. The RPA-CRISPR/Cas12a assay distinguished P. marginatus from 10 other mealybugs. The entire process can be completed in approximately an hour, and the identification results can be determined by the naked eye using lateral flow strips or a portable mini-UV torch. A method was developed to extract DNA from P. marginatus within 5 min. This method was combined with the RPA-CRISPR/Cas12a assay to achieve rapid and simple detection. In addition, two portable thermos cups with temperature displays were used to maintain the reagents and assay reactions in the field. CONCLUSION: This assay represents the first application of portable and easily available items (mini-UV torch and thermos cup) based on the combination of RPA and CRISPR/Cas12a for rapid pest detection. This method is rapid, highly specific, and instrument-flexible, allowing for the early monitoring of P. marginatus in the field. This study provides guidance for the development of suitable management strategies. © 2024 The Author(s). Pest Management Science published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

4.
Adv Mater ; 34(27): e2202382, 2022 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-35526081

RESUMO

The practical application of the Zn-metal anode for aqueous batteries is greatly restricted by catastrophic dendrite growth, intricate hydrogen evolution, and parasitic surface passivation. Herein, a polyanionic hydrogel film is introduced as a protective layer on the Zn anode with the assistance of a silane coupling agent (denoted as Zn-SHn). The hydrogel framework with zincophilic -SO3 - functional groups uniformizes the zinc ions flux and transport. Furthermore, such a hydrogel layer chemically bonded on the Zn surface possesses an anti-catalysis effect, which effectively suppresses both the hydrogen evolution reaction and formation of Zn dendrites. As a result, stable and reversible Zn stripping/plating at various currents and capacities is achieved. A full cell by pairing the Zn-SHn anode with a NaV3 O8 ·1.5 H2 O cathode shows a capacity of around 176 mAh g-1 with a retention around 67% over 4000 cycles at 10 A g-1 . This polyanionic hydrogel film protection strategy paves a new way for future Zn-anode design and safe aqueous batteries construction.

5.
Adv Sci (Weinh) ; 9(25): e2202204, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35748192

RESUMO

Lithium-sulfur batteries (LSBs) with extremely-high theoretical energy density (2600 Wh kg-1 ) are deemed to be the most likely energy storage system to be commercialized. However, the polysulfides shuttling and lithium (Li) metal anode failure in LSBs limit its further commercialization. Herein, a versatile asymmetric separator and a Li-rich lithium-magnesium (Li-Mg) alloy anode are applied in LSBs. The asymmetric separator is consisted of lithiated-sulfonated porous organic polymer (SPOP-Li) and Li6.75 La3 Zr1.75 Nb0.25 O12 (LLZNO) layers toward the cathode and anode, respectively. SPOP-Li serves as a polysulfides barrier and Li-ion conductor, while the LLZNO functions as an "ion redistributor". Combining with a stable Li-Mg alloy anode, the symmetric cell achieves 5300 h of Li stripping/plating and the modified LSBs exhibit a long lifespan with an ultralow fading rate of 0.03% per cycle for over 1000 cycles at 5 C. Impressively, even under a high-sulfur-loading (6.1 mg cm-2 ), an area capacity of 4.34 mAh cm-2 after 100 cycles can still be maintained, demonstrating high potential for practical application.

6.
Nanoscale ; 13(9): 4921-4930, 2021 Mar 12.
Artigo em Inglês | MEDLINE | ID: mdl-33625417

RESUMO

Li-rich high-Mn oxides, xLi2MnO3·(1 - x)LiMO2 (x ≥ 0.5, M = Co, Ni, Mn…), have attracted extensive research interest due to their high specific capacity and low cost. However, slow Li2MnO3 activation and poor cycling stability have affected their electrochemical performance. Herein, to solve these problems, morphology regulation and LiAlF4 coating strategies have been synergistically applied to a Li-rich high-Mn material Li1.7Mn0.8Co0.1Ni0.1O2.7 (HM-811). This dual-strategy successfully promotes the activation process of the Li2MnO3 phase and thus improves the electrochemical performance of HM-811. Theoretical computation indicates that the LiAlF4 layer has a lower Li+ migration barrier than the HM-811 matrix, so it could boost the diffusion of Li+ ions and promote the activation of the Li2MnO3 phase. Benefiting from the morphology regulation and LiAlF4 coating, the HM-811 cathode shows a high initial charge capacity of >300 mA h g-1. In addition, the modified HM-811 could deliver superior electrochemical performance even at a low temperature of -20 °C. This work provides a new approach for developing high performance cathode materials for next-generation Li-ion batteries.

7.
Bioorg Med Chem ; 18(8): 2864-71, 2010 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-20363145

RESUMO

A novel series of diphenolic chromone derivatives were synthesized and their inhibitory activity on nitric oxide (NO) production and cytotoxicity were evaluated using LPS-activated murine macrophages RAW264.7 assay and MTT method, respectively. Among these compounds, (5,7-dihydroxy-4-oxo-4H-chromen-3-yl) methyl esters (6b, 6c, 6f, 6g, and 6h) showed quite potent inhibitory activities with IC(50) values of 2.20, 3.48, 0.35, 0.80, and 0.61microM, respectively. The MTT results showed that all of the active compounds exhibited no cytotoxicity at the effective concentrations. The preliminary mechanism of the most potent compounds (6b, 6c, 6f, 6g, and 6h) was further examined based on the RT-PCR results and the compounds 6f, 6g, and 6h inhibited NO production by suppressing the expression of iNOS mRNA in a dose dependent manner. Furthermore, a computational analysis of physicochemical parameters revealed that the most of the compounds possessed drug-like properties.


Assuntos
Anti-Inflamatórios/síntese química , Cromonas/química , Inibidores Enzimáticos/síntese química , Macrófagos/metabolismo , Óxido Nítrico/metabolismo , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Linhagem Celular , Cromonas/síntese química , Cromonas/farmacologia , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Lipopolissacarídeos/toxicidade , Camundongos , Óxido Nítrico Sintase Tipo II/antagonistas & inibidores , Óxido Nítrico Sintase Tipo II/metabolismo
8.
J Biotechnol ; 290: 24-32, 2019 Jan 20.
Artigo em Inglês | MEDLINE | ID: mdl-30553805

RESUMO

Chiral ß-amino alcohols are very important chiral building block for preparing bioactive compounds for use in pharmaceutical and fine chemical industries. Synthesis of chiral ß-amino alcohols by transaminase is big challenging due to the strict substrate specificities and very low activity of the enzyme. In this work, a (R)-selective ω-transaminase (MVTA) from Mycobacterium vanbaalenii was employed as a biocatalyst for the first time for the synthesis of chiral ß-amino alcohol via kinetic resolution and asymmetric reductive amination. The enzyme was purified and characterized. Kinetic resolution of a set of racemic ß-amino alcohols including two cyclic ß-amino alcohols by MVTA was demonstrated, affording (R)-ß-amino alcohols, (1S, 2S)-trans-2-aminocyclopentanol and (1R, 2S)-cis-1-amino-2-indanols in >99% ee and 50-62% conversion. Asymmetric reductive amination of three α-hydroxy ketones (10-300 mM) by MVTA was conducted, (S)-ß-amino alcohols were obtained with >99% ee and 80-99% conversion. Preparation experiment for the reductive amination of 200 mM 2-hydroxyacetophenone by the resting cells of recombinant E. coli (MVTA) was proceeded smoothly and product (S)-2-amino-2-phenylethanol was obtained with 71% isolated yield, >99% ee and 68.6 g/L/d volumetric productivity. The current research proved that the MVTA is a robust enzyme for the preparation of chiral ß-amino alcohol with high volumetric productivity.


Assuntos
Amino Álcoois/metabolismo , Proteínas de Bactérias/metabolismo , Mycobacterium/enzimologia , Proteínas Recombinantes/metabolismo , Transaminases/metabolismo , Amino Álcoois/análise , Amino Álcoois/química , Proteínas de Bactérias/química , Proteínas de Bactérias/genética , Reatores Biológicos , Escherichia coli/genética , Cinética , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Estereoisomerismo , Transaminases/química , Transaminases/genética
9.
Pest Manag Sci ; 75(3): 639-647, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-30066468

RESUMO

BACKGROUND: Knowledge of the compatibility between spirodiclofen and the predator Oligota flavicornis is an important aspect for the management of spider mites. RESULTS: We used the age-stage, two-sex life table to assess the effects of spirodiclofen on the life history traits and population growth of O. flavicornis. At the maximum recommended concentration (60 mg a.i. L-1 ) and also at twice the maximum recommended dosage (120 mg a.i. L-1 ), the preadult stages of O. flavicornis were significantly lengthened, while the adult longevity and fecundity decreased significantly. The finite rate (λ), intrinsic rate of increase (r), and net reproduction rate (R0 ) decreased, while the mean generation time (T) was longer after both the 60 and 120 mg a.i. L-1 treatments than it was in the control and 30 mg a.i. L-1 treatments. Life expectancy and reproductive value were higher in the control and 30 mg a.i. L-1 treatment than in the 60 and 120 mg a.i. L-1 treatments; the two higher concentrations were detrimental to the development of O. flavicornis. CONCLUSION: A proper combination of the O. flavicornis and spirodiclofen to control the spider mite, while avoiding the side effect of spirodiclofen, could be achieved based on the knowledge of life tables. © 2018 Society of Chemical Industry.


Assuntos
4-Butirolactona/análogos & derivados , Acaricidas/efeitos adversos , Besouros/efeitos dos fármacos , Compostos de Espiro/efeitos adversos , 4-Butirolactona/efeitos adversos , Animais , Besouros/crescimento & desenvolvimento , Feminino , Fertilidade , Características de História de Vida , Masculino , Controle Biológico de Vetores , Crescimento Demográfico , Comportamento Predatório , Tetranychidae
10.
Steroids ; 150: 108431, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31229507

RESUMO

ß-Triazoly enones are biologically interesting scaffolds, incorporation of such scaffolds into the steroid nucleus may generate new bioactive steroids and further enrich structural types of steroids. In this work, a series of new steroidal ß-triazoly enones were synthesized based on click chemistry and Claisen-Schmidt condensation reaction and further evaluated for their antiproliferative activity against a panel of cancer cells. Most of these compounds showed better potency against PC-3 and MGC-803 cells. Particularly, compound 5a inhibited PC-3 and MGC-803 cells potently with the IC50 values of 1.61 and 1.16 µM, respectively, and was less toxic toward GES-1 with an IC50 value of 20.72 µM. Further mechanistic studies showed that compound 5a inhibited migration and invasion of MGC-803 and PC-3 dose-dependently. Treatment with compound 5a varied mRNA levels and protein expression of EMT markers in both cells. Collectively, the steroidal ß-triazoly enones could be potentially utilized to develop new anticancer agents with the ability of inhibiting cell migration and invasion.


Assuntos
Antineoplásicos/síntese química , Antineoplásicos/farmacologia , Movimento Celular/efeitos dos fármacos , Desenho de Fármacos , Cetonas/farmacologia , Esteroides/farmacologia , Triazóis/farmacologia , Antineoplásicos/química , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Cetonas/síntese química , Cetonas/química , Estrutura Molecular , Invasividade Neoplásica , Esteroides/síntese química , Esteroides/química , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/química
11.
Eur J Med Chem ; 181: 111520, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404863

RESUMO

A series of novel triazole nucleobase analogues containing steroidal/coumarin/quinoline moieties have been synthesized based on copper-catalyzed azide-alkyne cycloaddition (CuAAC). The anti-cancer activity of the new triazole nucleobase analogues was studied in gastric cancer cell lines (MGC-803, SGC-7901) and normal gastric epithelial cells (GES-1) in vitro. Some of the synthesized compounds could significantly inhibit the proliferation of these tested cancer cells. Among the tested compounds, compound 20c demonstrated good anti-proliferation activity against MGC-803 cells (IC50 = 1.48 µM) and SGC-7901 (IC50 = 2.28 µM) cells as well as the best selectivity between the cancer and normal cells. Further mechanistic studies indicated that compound 20c could down-regulate the expression of TGF ß1 both in the tested gastric cancer cell lines and inhibit the cell migration and invasion. The results of the study indicate that compound 20c could be used as a promising skeleton for anti-gastric cancer agents with improved efficacy and less side effects.


Assuntos
Antineoplásicos/farmacologia , Cumarínicos/farmacologia , Quinolinas/farmacologia , Esteroides/farmacologia , Neoplasias Gástricas/tratamento farmacológico , Triazóis/farmacologia , Antineoplásicos/síntese química , Antineoplásicos/química , Proliferação de Células/efeitos dos fármacos , Cumarínicos/química , Relação Dose-Resposta a Droga , Ensaios de Seleção de Medicamentos Antitumorais , Humanos , Estrutura Molecular , Quinolinas/química , Esteroides/química , Neoplasias Gástricas/patologia , Relação Estrutura-Atividade , Triazóis/síntese química , Triazóis/química , Células Tumorais Cultivadas
12.
Neurosci Res ; 62(2): 123-30, 2008 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-18675857

RESUMO

In the present study, protective effect of five isoflavones (formononetin, daidzein, pratensein, calycosin and irilone) from Trifolium pratense on lipopolysaccharide-induced dopaminergic neurodegeneration was studied for the first time. The results showed that all five isoflavones attenuated LPS-induced decrease in dopamine uptake and the number of dopaminergic neurons in a dose-dependent manner in rat mesencephalic neuron-glia cultures. Moreover, they also significantly inhibited LPS-induced activation of microglia and production of tumor necrosis factor-alpha, nitric oxide and superoxide in mesencephalic neuron-glia cultures and microglia-enriched cultures. In addition, the rank order of protective potency of five isoflavones was: pratensein>daidzein>calycosin>formononetin>irilone. This study suggested that all five isoflavones protected dopaminergic neurons against LPS-induced injury through inhibition of microglia activation and proinflammatory factors generation.


Assuntos
Isoflavonas/farmacologia , Degeneração Neural/prevenção & controle , Neurônios/efeitos dos fármacos , Extratos Vegetais/farmacologia , Trifolium/química , Animais , Dopamina/metabolismo , Imuno-Histoquímica , Inflamação/prevenção & controle , Lipopolissacarídeos/toxicidade , Microglia/efeitos dos fármacos , Degeneração Neural/induzido quimicamente , Neurônios/metabolismo , Ratos
13.
Neurosci Lett ; 448(2): 175-9, 2008 Dec 26.
Artigo em Inglês | MEDLINE | ID: mdl-18952146

RESUMO

Parkinson's disease is a neurodegenerative disorder characterized by progressive degeneration of dopaminergic neurons in the substantia nigra. Accumulating evidence has suggested that inflammation in the brain participates in the pathogenesis of Parkinson's disease. Luteolin, a polyphenolic compound found in foods of plant origin, belongs to the flavone subclass of flavonoids, and has been shown to possess antimutagenic, antitumorigenic, antioxidant and antiinflammatory properties. In this study, we found that luteolin concentration-dependently attenuated the lipopolysaccharide (LPS)-induced decrease in [(3)H]dopamine uptake and loss of tyrosine hydroxylase-immunoreactive neurons in primary mesencephalic neuron-glia cultures. Moreover, luteolin also significantly inhibited LPS-induced activation of microglia and excessive production of tumor necrosis factor-alpha, nitric oxide and superoxide in mesencephalic neuron-glia cultures and microglia-enriched cultures. Our results demonstrate that luteolin may protect dopaminergic neurons from LPS-induced injury and its efficiency in inhibiting microglia activation may underlie the mechanism.


Assuntos
Dopamina/metabolismo , Inflamação/fisiopatologia , Luteolina/farmacologia , Microglia/efeitos dos fármacos , Neurônios/efeitos dos fármacos , Fármacos Neuroprotetores/farmacologia , Análise de Variância , Animais , Técnicas de Cocultura , Lipopolissacarídeos , Mesencéfalo , Microglia/fisiologia , Neurônios/fisiologia , Óxido Nítrico/metabolismo , Ratos , Ratos Sprague-Dawley , Superóxidos/metabolismo , Trillium/metabolismo , Fator de Necrose Tumoral alfa/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo
14.
Water Sci Technol ; 58(5): 1079-84, 2008.
Artigo em Inglês | MEDLINE | ID: mdl-18824807

RESUMO

The presence of microystins (MCs) in water has the potential to harm people's health. In the MCs various isomers, MC-LR has the strongest toxicity and is the most harmful one. At present, several kinds of pre-oxidants, which are commonly used in water treatment process, are effective to remove MC-LR. However, it is still not clear about their degeneration mechanisms. Chlorine and potassium permanganate were selected in the present work since they are used worldwide for preoxidation treatment. Using the testing method of HPLC-MS, studies on the degeneration of MC-LR were conducted. The results indicate that HPLC-MS is creditable and sensitive. It was also found that linear relationship between concentration of MC-LR and peak area holds in the range of 5-500 microg.L(-1) on the calibration curves, the correlation coefficient (R2) is 0.9993. Under the general condition of oxidant dose and reaction time, MC-LR was degraded rapidly. With active chlorine and potassium permanganate the degradation reaction followed the mode of first-order kinetics. The molecular weight of the degradation product was determined through analyzing the full-scan mass spectrum of MC-LR. And the oxidative degradation mechanism of MC-LR was discussed as well.


Assuntos
Compostos Clorados/química , Cromatografia Líquida de Alta Pressão/métodos , Compostos de Manganês/química , Microcistinas/química , Óxidos/química , Permanganato de Potássio/química , Espectrometria de Massas em Tandem/métodos , Cinética , Purificação da Água/métodos
15.
J Environ Sci (China) ; 19(4): 464-8, 2007.
Artigo em Inglês | MEDLINE | ID: mdl-17915711

RESUMO

The pollutant loads of surface runoff in an urban tourist area have been investigated for two years in the Wuhan City Zoo, China. Eight sampling sites, including two woodlands, three animal yards, two roofs and one road, were selected for sampling and study. The results indicate that pollutants ranked in a predictable order of decreasing load (e.g. animal yard > roof > woodland > road), with animal yards acting as the key pollution source in the zoo. Pollutants were transported mainly by particulate form in runoff. Particulate nitrogen and particulate phosphorous accounted on average for 61%, 78% of total pollutant, respectively, over 13 monitored rainfall events. These results indicate the treatment practices should be implemented to improve particulate nutrient removal. Analysis of the M(V) curve indicate that no first flush effect existed in the surface runoff from pervious areas (e.g. woodland, animal ground yard), whereas a first flush effect was evident in runoff from impervious surfaces (e.g. animal cement yard, roof, road).


Assuntos
Nitrogênio/análise , Fósforo/análise , Chuva , Movimentos da Água , Poluentes Químicos da Água/análise , China , Cidades , Monitoramento Ambiental
16.
Sci Rep ; 7: 40803, 2017 01 23.
Artigo em Inglês | MEDLINE | ID: mdl-28112233

RESUMO

The whitefly Bemisia tabaci (Gennadius) is an important agricultural insect pest worldwide. The B and Q biotypes are the two most predominant and devastating biotypes prevalent across China. However, there are few studies regarding the occurrence of the Q biotype in Fujian Province, China, where high insecticide resistance has been reported in the B biotype. Differences in some biological characteristics between the B and Q biotypes, especially insecticide resistance, are considered to affect the outcome of their competition. Extensive surveys in Fujian revealed that the B biotype was predominant during 2005-2014, whereas the Q biotype was first detected in some locations in 2013 and widely detected throughout the province in 2014. Resistance to neonicotinoids (that have been used for more than 10 years) exhibited fluctuations in open fields, but showed a continual increasing trend in protected areas. Resistance to lambda-cyhalothrin, chlorpyrifos, and abamectin exhibited a declining trend. Resistance to novel insecticides, such as nitenpyram, pymetrozine, sulfoxaflor, and cyantraniliprole, in 2014 was generally below a moderate level. A decline in insecticide resistance in the B biotype and the rapid buildup of protected crops under global temperature increase may have promoted the establishment of the Q biotype in Fujian.


Assuntos
Biodiversidade , Hemípteros/classificação , Hemípteros/efeitos dos fármacos , Resistência a Inseticidas , Inseticidas/farmacologia , Animais , China , Demografia , Ecossistema , Geografia
17.
J Econ Entomol ; 110(6): 2334-2341, 2017 12 05.
Artigo em Inglês | MEDLINE | ID: mdl-29220518

RESUMO

The effect of nine constant temperatures on developmental time of Oligota flavicornis (Boisduval and Lacordaire) preying on Tetranychus cinnabarinus (Boisduval) (Acari: Tetranychidae) eggs was determined under laboratory conditions of 75 ± 5% RH and a 16:8 (L:D) h photoperiod. O. flavicornis survival rates were highest between 18 and 30°C, although O. flavicornis eggs developed successfully to adults at 12-32°C, and the developmental durations to adult at the seven temperatures (12, 15, 18, 20, 25, 30, and 32°C) were 114.41, 51.66, 33.45, 23.21, 13.43, 11.54, and 17.18 d, respectively. Two linear and seven nonlinear models (Logan-6 and Logan-10, Taylor, Lactin-1 and Lactin-2, and Brière-1 and Brière-2) were fit to the developmental rates of the immature predatory stages to estimate the thermal constant (K) and critical temperatures. The lower temperature threshold (T0) and K for the immature stages using the common linear model were 9.96°C and 225.73 degree-days and Ikemoto-Takai linear model were 11.01°C and 167.14 degree-days, respectively. The upper temperature threshold values estimated by the Logan-6 and Lactin-1 models were both 34.86°C. The T0 values estimated by the Brière-1 and Brière-2 models were 10.67 and 9.32°C for all immature stages, respectively, and the estimated optimal temperature according to the Brière-2 model was 29.59°C. Therefore, the two linear models and Brière-2 model estimates approximated the actual relationship between the temperature and developmental rate of immature O. flavicornis.


Assuntos
Besouros/crescimento & desenvolvimento , Controle Biológico de Vetores , Comportamento Predatório , Tetranychidae , Animais , Besouros/fisiologia , Larva/crescimento & desenvolvimento , Larva/fisiologia , Modelos Lineares , Longevidade , Modelos Biológicos , Dinâmica não Linear , Pupa/crescimento & desenvolvimento , Pupa/fisiologia , Temperatura , Tetranychidae/crescimento & desenvolvimento
18.
Small ; 1(4): 422-8, 2005 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-17193467

RESUMO

Novel flowerlike nanostructures consisting of MgO nanofibers were successfully synthesized by a simple chemical route with H(2)O at 950 degrees C in an Ar atmosphere. Various durations of heating gave different growth stages that led to varied product morphologies. The synthesized products were systematically studied by X-ray powder diffraction, scanning electron microscopy, high-resolution transmission electron microscopy, and energy-dispersive X-ray analysis. The results show that the nucleation and growth process of the nanoflowers seems to be a vapor-solid mechanism, and that the total heating time during the reaction process is a critical factor for the development of MgO nanoflowers. Initially, Mg particles formed on the Si substrate, followed by the formation of MgO clusters as nucleation centers on the magnesium melt surface and the nucleation of short MgO nanofibers, then growth of the MgO nanofibers occurred, and finally MgO nanoflowers were formed. Besides nanoflowers, novel hierarchical MgO nanostructures were also observed. These nanostructures may be used as three-dimensional composite materials and as supports for other materials.


Assuntos
Óxido de Magnésio/química , Nanopartículas/química , Nanoestruturas/química , Nanotecnologia/instrumentação , Nanotecnologia/métodos , Química/métodos , Cristalização , Teste de Materiais , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Conformação Molecular , Nanotubos/química , Oxigênio/química , Tamanho da Partícula , Silício/química , Difração de Raios X
19.
Huan Jing Ke Xue ; 36(8): 2809-16, 2015 Aug.
Artigo em Zh | MEDLINE | ID: mdl-26592007

RESUMO

Six kinds of impermeable underlying surface, cement tile roof, asbestos roof, cement flat roof, residential concrete pavement, asphalt pavement of restaurants, asphalt pavement of oil depot, and a combined sewer overflow canal in the Jiansheng town of Dadukou district in Chongqing city were chosen as sample plots to study the characteristics of nutritional pollutants and heavy metals in town runoff. The research showed that the average mass concentrations of TSS, COD, TN, TP in road runoff were (1681.2 +/- 677.2), (1154.7 +/- 415.5), (12.07 +/- 2.72), (3.32 +/- 1.15) mgL(-1), respectively. These pollutants were higher than those in roof runoff which were (13.3 +/- 6.5), (100.4 +/- 24.8), (3.58 +/- 0.70), (0.10 +/- 0.02) mg x L(-1), respectively. TDN accounted for 62.60% +/- 34.38% of TN, and TDP accounted for 42.22% +/- 33.94% of TP in the runoff of impermeable underlying surface. Compared with the central urban runoff, town runoff in our study had higher mass concentrations of these pollutants. The mass concentrations of TSS, COD, TDN, TN, TDP and TP in the combined sewer overflow were (281.57 +/- 308.38), (231.21 +/- 42.95), (8.16 +/- 2.78), (10.60 +/- 3.94), (0.38 +/- 0.23) and (1.51 +/- 0.75) mg x L(-1), respectively. The average levels of heavy metals in this kind of runoff did not exceed the class VI level of the surface water environmental quality standard. Most pollutants in the combined sewer overflow had first flush. However, this phenomenon was very rare for TSS. There was a significant positive correlation between TSS and COD, TP in the combined sewer overflow. And this correlation was significant between NH4+ -N and TP, TDP, TN, TDP. However, a negative correlation existed between NO3- -N and all other indicators.


Assuntos
Chuva , Movimentos da Água , Poluentes Químicos da Água/análise , China , Cidades , Monitoramento Ambiental , Metais Pesados/análise , Qualidade da Água
20.
Chemosphere ; 128: 49-55, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25655818

RESUMO

Given expectations for a booming usage of thiamethoxam and increasing availability of the promising biological agent Serangium japonicum for the control of Bemisia tabaci in China, an evaluation of their compatibility is crucial for integrated pest management (IPM). This study examined the lethal and sublethal effects of thiamethoxam on S. japonicum through three exposure routes. An acute toxicity bioassay showed that LC50 values of thiamethoxam for S. japonicum through residue contact, egg-dip, and systemic treatment were 6.65, 4.37, and 2.43 mg AI L(-1), respectively. The prey consumption of S. japonicum given different densities of B. tabaci eggs under control, discontinuous, egg-dip and systemic exposure scenarios showed a good fit to a Type II functional response. Predation of S. japonicum was most affected under systemic exposure, followed by egg-dip, and discontinuous, which was only slightly affected. In all cases tested, however, predators recovered their predation capacity rapidly, either after 24h of exposure or 24h after the end of exposure. Thiamethoxam was highly toxic to S. japonicum regardless of exposure routes. Sublethal effects of thiamethoxam applied systemically or foliar both impaired the biological control of S. japonicum on B. tabaci. Therefore, thiamethoxam should be used with caution in IPM of B. tabaci.


Assuntos
Besouros/efeitos dos fármacos , Inseticidas/toxicidade , Nitrocompostos/toxicidade , Oxazinas/toxicidade , Comportamento Predatório/efeitos dos fármacos , Tiazóis/toxicidade , Animais , China , Feminino , Neonicotinoides , Tiametoxam
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