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1.
Front Microbiol ; 15: 1333526, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38318338

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) is a leading threat to public health as it is resistant to most currently available antibiotics. Prodigiosin is a secondary metabolite of microorganisms with broad-spectrum antibacterial activity. This study identified a significant antibacterial effect of prodigiosin against MRSA with a minimum inhibitory concentration as low as 2.5 mg/L. The results of scanning electron microscopy, crystal violet staining, and confocal laser scanning microscopy indicated that prodigiosin inhibited biofilm formation in S. aureus USA300, while also destroying the structure of the cell wall and cell membrane, which was confirmed by transmission electron microscopy. At a prodigiosin concentration of 1.25 mg/L, biofilm formation was inhibited by 76.24%, while 2.5 mg/L prodigiosin significantly reduced the vitality of MRSA cells in the biofilm. Furthermore, the transcriptomic results obtained at 1/8 MIC of prodigiosin indicated that 235and 387 genes of S. aureus USA300 were significantly up- and downregulated, respectively. The downregulated genes were related to two-component systems, including the transcriptional regulator LytS, quorum sensing histidine kinases SrrB, NreA and NreB, peptidoglycan biosynthesis enzymes (MurQ and GlmU), iron-sulfur cluster repair protein ScdA, microbial surface components recognizing adaptive matrix molecules, as well as the key arginine synthesis enzymes ArcC and ArgF. The upregulated genes were mainly related to cell wall biosynthesis, as well as two-component systems including vancomycin resistance-associated regulator, lipoteichoic acid biosynthesis related proteins DltD and DltB, as well as the 9 capsular polysaccharide biosynthesis proteins. This study elucidated the molecular mechanisms through which prodigiosin affects the cell envelope of MRSA from the perspectives of cell wall synthesis, cell membrane and biofilm formation, providing new potential targets for the development of antimicrobials for the treatment of MRSA.

2.
Insects ; 14(4)2023 Apr 06.
Artigo em Inglês | MEDLINE | ID: mdl-37103178

RESUMO

Tuta absoluta (Meyrick) is a devastating invasive pest worldwide. The abamectin and chlorantraniliprole complex have become an alternative option for chemical control because they can enhance insecticidal activity and delay increased drug resistance. Notably, pests are inevitably resistant to various types of insecticides, and compound insecticides are no exception. To identify potential genes involved in the detoxification of abamectin and chlorantraniliprole complex in T. absoluta, PacBio SMRT-seq transcriptome sequencing and Illumina RNA-seq analysis of abamectin and chlorantraniliprole complex-treated T. absoluta were performed. We obtained 80,492 non-redundant transcripts, 62,762 (77.97%) transcripts that were successfully annotated, and 15,524 differentially expressed transcripts (DETs). GO annotation results showed that most of these DETs were involved in the biological processes of life-sustaining activities, such as cellular, metabolic, and single-organism processes. The KEGG pathway enrichment results showed that the pathways related to glutathione metabolism, fatty acid and amino acid synthesis, and metabolism were related to the response to abamectin and chlorantraniliprole complex in T. absoluta. Among these, 21 P450s were differentially expressed (11 upregulated and 10 downregulated). The qRT-PCR results for the eight upregulated P450 genes after abamectin and chlorantraniliprole complex treatment were consistent with the RNA-Seq data. Our findings provide new full-length transcriptional data and information for further studies on detoxification-related genes in T. absoluta.

3.
Virol Sin ; 36(4): 774-783, 2021 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-33689141

RESUMO

Lassa virus (LASV) belongs to the Mammarenavirus genus (family Arenaviridae) and causes severe hemorrhagic fever in humans. The glycoprotein complex (GPC) contains eleven N-linked glycans that play essential roles in GPC functionalities such as cleavage, transport, receptor recognition, epitope shielding, and immune response. We used three mutagenesis strategies (asparagine to glutamine, asparagine to alanine, and serine/tyrosine to alanine mutants) to abolish individual glycan chain on GPC and found that all the three strategies led to cleavage inefficiency on the 2nd (N89), 5th (N119), or 8th (N365) glycosylation motif. To evaluate N to Q mutagenesis for further research, it was found that deletion of the 2nd (N89Q) or 8th (N365Q) glycan completely inhibited the transduction efficiency of pseudotyped particles. We further investigated the role of individual glycan on GPC-mediated immune response by DNA immunization of mice. Deletion of the individual 1st (N79Q), 3rd (N99Q), 5th (N119Q), or 6th (N167Q) glycan significantly enhanced the proportion of effector CD4+ cells, whereas deletion of the 1st (N79Q), 2nd (N89Q), 3rd (N99Q), 4th (N109Q), 5th (N119Q), 6th (N167Q), or 9th (N373Q) glycan enhanced the proportion of CD8+ effector T cells. Deletion of specific glycan improves the Th1-type immune response, and abolishment of glycan on GPC generally increases the antibody titer to the glycan-deficient GPC. However, the antibodies from either the mutant or WT GPC-immunized mice show little neutralization effect on wild-type LASV. The glycan residues on GPC provide an immune shield for the virus, and thus represent a target for the design and development of a vaccine.


Assuntos
Vírus Lassa , Envelope Viral , Animais , Imunidade , Vírus Lassa/genética , Camundongos , Polissacarídeos , Proteínas do Envelope Viral
4.
Neurotox Res ; 39(2): 456-466, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33247828

RESUMO

Chitosan nanoparticles and valproic acid are demonstrated as the protective agents in the treatment of spinal cord injury (SCI). However, the effects of valproic acid-labeled chitosan nanoparticles (VA-CN) on endogenous spinal cord neural stem cells (NSCs) following SCI and the underlying mechanisms involved remain to be elucidated. In this study, the VA-CN was constructed and the effects of VA-CN on NSCs were assessed in a rat model of SCI. We found VA-CN treatment promoted recovery of the tissue and locomotive function following SCI. Moreover, administration of VA-CN significantly enhanced neural stem cell proliferation and the expression levels of neurotrophic factors following SCI. Furthermore, administration of VA-CN led to a decrease in the number of microglia following SCI. In addition, VA-CN treatment significantly increased the Tuj 1- positive cells in the spinal cord of the SCI rats, suggesting that VA-CN could enhance the differentiation of NSCs following SCI. In conclusion, these results demonstrated that VA-CN could improve the functional and histological recovery through promoting the proliferation and differentiation of NSCs following SCI, which would provide a newly potential therapeutic manner for the treatment of SCI.


Assuntos
Diferenciação Celular/efeitos dos fármacos , Proliferação de Células/efeitos dos fármacos , Quitosana/administração & dosagem , Nanopartículas/administração & dosagem , Células-Tronco Neurais/efeitos dos fármacos , Traumatismos da Medula Espinal/fisiopatologia , Ácido Valproico/administração & dosagem , Animais , Locomoção/efeitos dos fármacos , Masculino , Ratos Sprague-Dawley
5.
Aging (Albany NY) ; 12(10): 8953-8967, 2020 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-32463791

RESUMO

Chitosan nanoparticles have been recognized as a new type of biomaterials for treatment of spinal cord injury (SCI). To develop a novel treatment method targeted delivery injured spinal cord, valproic acid labeled chitosan nanoparticles (VA-CN) were constructed and evaluated in the treatment of SCI. Our results demonstrated that administration of VA-CN significantly promoted the recovery of the function and tissue repair after SCI. Moreover, we found treatment of VA-CN inhibited the reactive astrocytes after SCI. Furthermore, administration of VA-CN enhanced immunoreactions of neuronal related marker NF160, which suggested that VA-CN could promote the neuroprotective function in rats of SCI. The production of IL-1ß, IL-6 and TNF-α were significantly decreased following treatment of VA-CN. Meanwhile, administration of VA-CN effectively improved the blood spinal cord barrier (BSCB) disruption after SCI. Administration of VA-CN could enhance the recovery of neuronal injury, suppress the reactive astrocytes and inflammation, and improve the blood spinal cord barrier disruption after SCI in rats. These results provided a novel and promising therapeutic manner for SCI.


Assuntos
Quitosana/química , Nanopartículas/química , Recuperação de Função Fisiológica/efeitos dos fármacos , Traumatismos da Medula Espinal/metabolismo , Ácido Valproico , Animais , Masculino , Ratos , Ratos Sprague-Dawley , Medula Espinal/efeitos dos fármacos , Ácido Valproico/química , Ácido Valproico/farmacologia
6.
Materials (Basel) ; 12(15)2019 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-31357678

RESUMO

The engineered cementitious composite (ECC) mixtures were prepared with Portland cement, ground fly ash, silica sand, and polyvinyl alcohol (PVA) fibers. Accordingly, four mix design factors with five levels each were designed using the Taguchi method. The engineering properties of ECC (flow expansion, compressive strength, flexural strength, charge passed, and maximum freeze-thaw cycle) were evaluated, and the single-response optimizations were conducted separately. Unlike other studies assigning a relative weighting parameter to each response, the principal component analysis (PCA) was innovatively introduced to optimize the ECC's multiple responses so that the single principal performance was obtained from the most objective perspective. Furthermore, the weighting parameters for utility concept were determined by the PCA. Thereafter, an optimum mix formulation was estimated using the PCA-based Taguchi method and the updated utility concept, which provided the most desired balance of these engineering properties. Finally, the contribution of each mix design factor to the principal performance of ECC was examined, and the estimated mix formulation was verified via an additional experiment.

7.
Materials (Basel) ; 12(11)2019 Jun 04.
Artigo em Inglês | MEDLINE | ID: mdl-31167358

RESUMO

This paper investigates the freeze-thaw performance of engineered cementitious composites (ECC) reinforced with polyvinyl alcohol (PVA) fibers, by applying an innovative criterion for judging the specimen's working state mutation. The ECC materials are prepared into 25 mixtures using the Taguchi method. Then, the fundamental transverse frequency, the flexural performance and the internal strain variation of ECC specimens subjected to freeze-thaw cycles are measured. Unlike the existing studies, this investigation focuses on the failure behavior of ECC materials in the process of freeze-thaw. The Mann-Kendall (M-K) criterion is introduced to detect the ECC specimen's working state leap feature, leading to the updated definition of frost-induced failure concept. Furthermore, the three-level model for evaluating the freeze-thaw performance of ECC materials is established according to the revealed essential leap feature. Thus, the effect of each individual mix design factor on the frost-induced failure indices is perceived from the signal-to-noise (S/N) ratio analysis and the analysis of variance (ANOVA). Finally, a mix formulation estimated based on Taguchi method is recommended for its optimum resistance against frost-induced failure, which is verified by the confirmation experiment.

8.
Antiviral Res ; 165: 11-22, 2019 05.
Artigo em Inglês | MEDLINE | ID: mdl-30822450

RESUMO

Respiratory syncytial virus (RSV) infection causes significant disease in the lower respiratory tract of young children, and there is currently no licensed vaccine to prevent RSV infection. The F glycoprotein is considered a major antigenic target for RSV vaccine development. Recent evidence indicates that the pre-fusion F state, compared with the post-fusion F state, is a superior antigen for generation of neutralizing antibodies. In this study, we developed a novel vaccine antigen, RSV glycoprotein F fused with an IgG Fc fragment (F-Fc). The F-Fc fusion protein is predominantly a hexamer and could be recognized by the pre-fusion F-specific monoclonal antibody D25. Intranasal immunization with the F-Fc fusion protein promoted a protective Th1-biased cellular immune response relative to that promoted by immunization with the F protein. This immunization strategy significantly reduced the lung viral load in mice. Furthermore, immunization with F-Fc reduced lung pathology and the production of pro-inflammatory cytokines and chemokines in the lung after RSV infection. These results suggest that the F-Fc protein may be a safe and effective RSV vaccine candidate.


Assuntos
Anticorpos Neutralizantes/uso terapêutico , Fragmentos Fc das Imunoglobulinas/uso terapêutico , Lesão Pulmonar/virologia , Vacinas contra Vírus Sincicial Respiratório/uso terapêutico , Proteínas Virais de Fusão/imunologia , Animais , Fragmentos Fc das Imunoglobulinas/imunologia , Pulmão/virologia , Lesão Pulmonar/tratamento farmacológico , Lesão Pulmonar/patologia , Camundongos , Infecções por Vírus Respiratório Sincicial/tratamento farmacológico , Infecções por Vírus Respiratório Sincicial/imunologia , Infecções por Vírus Respiratório Sincicial/patologia , Vírus Sinciciais Respiratórios/imunologia
9.
RSC Adv ; 9(26): 14662-14669, 2019 May 09.
Artigo em Inglês | MEDLINE | ID: mdl-35516300

RESUMO

A histone methyltransferase G9a, encoded by euchromatic histone-lysine N-methyltransferase 2 (EHMT2), is up-regulated in various cancers, and is involved in their poor prognosis. In the study reported here, the abnormal expression of G9a in gastric cancer it was investigated in vitro and in vivo. Furthermore, the expression of G9a was revealed to have a negative correlation with chemotherapy response in gastric cancer patients. Next, the effect of G9a knockdown on fluorouracil (5-FU) induced cell apoptosis in gastric cancer cells was focused on. The results demonstrated that G9a knockdown significantly activated the expression level of phospho c-Jun N-terminal kinase (p-JNK) and increased the intracellular reactive oxygen species (ROS) levels in the gastric cancer cells. Inhibition of the ROS/JNK signaling partial reversed the effect of G9a knockdown on 5-FU treated gastric cancer cells. Down-regulation of G9a enhanced the sensitivity of 5-FU to the gastric cancer cells in vitro and in vivo, which was involved in the activation of the ROS/JNK signaling pathway. These results demonstrated that G9a could play a critical role in the sensitivity of chemotherapy for gastric cancer and might be a novel method for treating gastric cancer in the clinic.

10.
Oncol Rep ; 39(1): 425-432, 2018 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-29115562

RESUMO

Cervical cancer, resulting from infection with human papillomavirus (HPV)16, remains the fourth most common cancer in women worldwide. Recently, three prophylactic HPV vaccines targeting high-risk HPVs (particularly HPV16 and HPV18) have been implemented to protect younger women. However, individuals with pre-existing infections have no benefit from prophylactic vaccines. Thus, there is an urgent need to develop therapeutic vaccines. HPV16 E7 has been widely utilized as a target for immune therapy of HPV16-associated lesions or cancers, reflecting the sustained existence of this virus in cancerous cells. We developed mannosylated HPV16 E7 (mE7) expressed from Pichia pastoris as a therapeutic vaccine against HPV16-associated cancer. Unmannosylated E7 (E7) was also generated from Pichia pastoris as a control. Mannosylation enhanced the uptake of mE7 by mannose receptors of bone marrow-derived dendritic cells (BMDCs), while the uptake of E7 was unaffected. mE7-uptake BMDCs in vitro induced more IFN-γ secretion by splenocytes of immunized mice than E7. Vaccination of C57BL/6 mice with mE7 combined with adjuvant monophosphoryl lipid A (MPL) elicited stronger Th1 (type 1 T helper cell) responses and E7-specific T cell responses than E7. The mE7 vaccine induced the increased production of IFN-γ, IL-2 and TNF-α, elicited more E7-specific IFN-γ-secreting CD8+ T cells in spleen and peripheral blood mononuclear cells (PMBCs) and promoted stronger E7-specific cytotoxic CD8+ T cell responses compared with E7. Furthermore, TC-1 tumor challenged mice were used to confirm the antitumor activity of the vaccines. As a result, mE7 generated complete antitumor activity against TC-1 tumors, while E7 only provided partial antitumor activity. Taken together, mE7 can be a promising immunotherapy for treating cervical cancer.


Assuntos
Vacinas Anticâncer/farmacologia , Papillomavirus Humano 16/imunologia , Manose/química , Proteínas E7 de Papillomavirus/farmacologia , Infecções por Papillomavirus/prevenção & controle , Neoplasias do Sistema Respiratório/virologia , Animais , Vacinas Anticâncer/genética , Vacinas Anticâncer/imunologia , Células Dendríticas/imunologia , Feminino , Papillomavirus Humano 16/genética , Papillomavirus Humano 16/metabolismo , Humanos , Imunização , Interferon gama/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Proteínas E7 de Papillomavirus/química , Proteínas E7 de Papillomavirus/genética , Proteínas E7 de Papillomavirus/imunologia , Infecções por Papillomavirus/imunologia , Pichia/genética , Pichia/crescimento & desenvolvimento , Engenharia de Proteínas , Neoplasias do Sistema Respiratório/imunologia , Neoplasias do Sistema Respiratório/prevenção & controle , Ensaios Antitumorais Modelo de Xenoenxerto
11.
Virol Sin ; 31(2): 160-7, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-27113243

RESUMO

Synthetic biology is a newly developed field of research focused on designing and rebuilding novel biomolecular components, circuits, and networks. Synthetic biology can also help understand biological principles and engineer complex artificial metabolic systems. DNA manipulation on a large genome-wide scale is an inevitable challenge, but a necessary tool for synthetic biology. To improve the methods used for the synthesis of long DNA fragments, here we constructed a novel shuttle vector named pGF (plasmid Genome Fast) for DNA assembly in vivo. The BAC plasmid pCC1BAC, which can accommodate large DNA molecules, was chosen as the backbone. The sequence of the yeast artificial chromosome (YAC) regulatory element CEN6-ARS4 was synthesized and inserted into the plasmid to enable it to replicate in yeast. The selection sequence HIS3, obtained by polymerase chain reaction (PCR) from the plasmid pBS313, was inserted for screening. This new synthetic shuttle vector can mediate the transformation-associated recombination (TAR) assembly of large DNA fragments in yeast, and the assembled products can be transformed into Escherichia coli for further amplification. We also conducted in vivo DNA assembly using pGF and yeast homologous recombination and constructed a 31-kb long DNA sequence from the cyanophage PP genome. Our findings show that this novel shuttle vector would be a useful tool for efficient genome-scale DNA reconstruction.


Assuntos
Sequência de Bases , DNA/metabolismo , Escherichia coli/genética , Vetores Genéticos/genética , Saccharomyces cerevisiae/genética , Cromossomos Artificiais de Levedura , Clonagem Molecular , DNA/genética , DNA/isolamento & purificação , DNA Bacteriano/genética , DNA Fúngico/genética , Eletroporação/métodos , Escherichia coli/metabolismo , Vetores Genéticos/metabolismo , Hidroliases/genética , Plasmídeos/genética , Recombinação Genética , Elementos Reguladores de Transcrição , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/genética , Biologia Sintética/métodos , Transformação Genética
12.
Biochim Biophys Acta ; 1864(4): 346-58, 2016 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-26779934

RESUMO

Prion diseases are a group of neurodegenerative diseases caused by prion protein (PrP) conformational changes. More than 30 PRNP gene mutations have been associated with familial prion diseases. E200K-associated familial Creutzfeldt-Jakob disease (fCJD) is the most common inherited prion disease. One of the hallmarks of prion diseases is the accumulation of oxidative damage. The mechanism by which oxidative modification of methionine (Met) residues influence the E200K PrP misfolding remains unclear. Here, we examined the stability, structural change, oligomerization and proteinase K resistance of unoxidized/oxidized E200K PrP and Met-to-Leu mutants. We found that oxidation of surface-exposed Met109/112/129/134/154/166 residues significantly destabilized E200K PrP but had a limited impact on the protein's structure. The oxidation of Met213 was the initial step in the conformational conversion of E200K PrP and facilitated the further oxidation of Met205/206. The oxidation of Met213/205/206 led to the exposure of the inner hydrophobic core, disrupted the overall structure of E200K PrP and induced the formation of large soluble multimers at low pH. In addition, the aggregation behavior of oxidized E200K PrP at the cellular level was investigated using E200K PrP Met-to-Ser mutants. The results showed that M109/112/129/154S or M134/166S mutants were efficiently localized on the cell membrane, whereas the M213/205/206S mutant generated many of aggregated fluorescent dots in the cytoplasm. The present work provides important clues for understanding the special roles of methionine oxidation in E200K PrP misfolding and links oxidative stress and consequent misfolding of oxidative damaged E200K PrP with the pathogenic mechanism of E200K-associated fCJD.


Assuntos
Síndrome de Creutzfeldt-Jakob/etiologia , Metionina/química , Príons/química , Dobramento de Proteína , Humanos , Concentração de Íons de Hidrogênio , Oxirredução , Agregados Proteicos , Multimerização Proteica
13.
Biochim Biophys Acta ; 1842(12 Pt A): 2345-56, 2014 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-25281825

RESUMO

The D178N mutation of the prion protein (PrP) results in the hereditary prion disease fatal familial insomnia (FFI). Little is known regarding the effects of methionine oxidation on the pathogenesis of D178N-associated FFI. In the present study, we found that the D178N variant was more susceptible to oxidation than wild-type PrP, as indicated by reverse-phase high performance liquid chromatography (RP-HPLC) and mass spectrometry (MS) analysis. Circular dichroism (CD), differential scanning calorimetry (DSC), thioflavin T (ThT) binding assay studies demonstrated that methionine oxidation decreased the structural stability of the D178N variant, and the oxidized D178N variant exhibited a greater propensity to form ß-sheet-rich oligomers and aggregates. Moreover, these aggregates of oxidized D178N PrP were more resistant to proteinase K (PK) digestion. Additionally, using fluorescence confocal microscopy, we detected a high degree of aggregation in D178N-transfected Neuro-2a (N2a) cells after treatment with hydrogen peroxide (H2O2). Furthermore, the oxidation and consequent aggregation of the D178N variant induced greater apoptosis of N2a cells, as monitored using flow cytometry. Collectively, these observations suggest that methionine oxidation accelerates the aggregation and enhances the neurotoxicity of the D178N variant, possibly providing direct evidence to link the pathogenesis of D178N-associated FFI with methionine oxidation.


Assuntos
Metionina/metabolismo , Mutação de Sentido Incorreto , Síndromes Neurotóxicas/genética , Príons/genética , Animais , Apoptose/efeitos dos fármacos , Apoptose/genética , Linhagem Celular Tumoral , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Endopeptidase K/metabolismo , Predisposição Genética para Doença/genética , Humanos , Peróxido de Hidrogênio/farmacologia , Insônia Familiar Fatal/genética , Insônia Familiar Fatal/metabolismo , Espectrometria de Massas/métodos , Microscopia Confocal , Síndromes Neurotóxicas/metabolismo , Oxidantes/farmacologia , Oxirredução , Príons/química , Príons/metabolismo , Conformação Proteica/efeitos dos fármacos , Estrutura Secundária de Proteína/efeitos dos fármacos
14.
Ying Yong Sheng Tai Xue Bao ; 25(9): 2563-8, 2014 Sep.
Artigo em Chinês | MEDLINE | ID: mdl-25757306

RESUMO

Mangrove wetland ecosystem in Quanzhou Bay in Fujian Province is newly restored with a regular semidiurnal tide. Soil CO2 concentration in the mangrove soil was determined by Li-840 portable gas analyzer, and periodic characteristics of soil CO2 emission was investigated. The soil CO2 flux in the wetland soil was relatively small because the mangrove was young. The change trends of soil CO2 concentration and flux with time were consistent in Kandelia obovate and Aegiceras corniculatum communities in the intertidal periods. The CO2 concentration and flux in the wetland soil were 557.08-2211.50 µmol · mol(-1) and -0.21-0.40 µmol · m(-2) · s(-1), respectively. The average CO2 flux in the wetland soil was 0.26 µmol · mol(-1) · s(-1) in the intertidal of morning and evening tides (early intertidal) and -0.01 µmol · m(-2) · s(-1) in the intertidal of evening and morning tides (late intertidal), respectively. At the same time after the tide, the concentration and flux of CO2 in the mangrove soil in early intertidal was higher than that in late intertidal. In early intertidal, the relationship between the flux and instantaneous concentration of CO2 in the wetland soil was expressed as a bell-shaped curve, and CO2 flux increased first and then decreased with the increasing CO2 concentration, which was in conformity with Gaussian distribution.


Assuntos
Dióxido de Carbono/análise , Solo/química , Áreas Alagadas , Baías , China , Rhizophoraceae
15.
Zhongguo Fei Ai Za Zhi ; 9(5): 399-404, 2006 Oct 20.
Artigo em Chinês | MEDLINE | ID: mdl-21176458

RESUMO

BACKGROUND: With the development of patch clamp and molecular biology technique, and the application of them in the investigation of tumor cellular membrane ion channnel, the ion channel is becoming the hot spot of the tumor base research gradually. The aim of this study is to investigate the electrophysiological properties of human lung adenocarcinoma cell line A-549 and the role of K+ channel in inhibition of cell proliferation by the recombinant mutant human tumor necrosis factor (rmhTNF). METHODS: Ionic currents were recorded using the whole-cell patch clamp recording technique. The proliferation activity of A-549 cells was measured by MTT assay. The cell cycle and apoptosis rates of the carcinoma cells were measured by flow cytometric analysis (FCM). RESULTS: Whole-cell patch clamp recording revealed a voltage-gated K+ current in A-549 cells, which could be blocked by the K+ channel blocker, TEA and CsCl. The amplitude of K+ current was markedly diminished in all cells incubated with different concentration of rmhTNF (P < 0.01). Obvious inhibitive effect of rmhTNF on proliferation of the cells was found in vitro in a dose-dependent manner (P < 0.01), the maximal inhibitory rate was 38.68% when the concentration was 400U/mL. The rmhTNF inhibited the cell cycle shifting from G1 phase to S phase and promoted apoptosis as determined by FCM analysis. The proportion of G1 cells increased from 53.02% to 72.93%, and the apoptosis rate increased from 2.08% to 8.68%. The difference were significant between the control and the high concentration groups ( 200U/mL and 400U/mL) (P < 0.01). CONCLUSIONS: rmhTNF exerts its cytotoxic effects on A-549 cells through inhibiting cell cycle shifting and inducing apoptosis. The K+ channels on the A-549 cell membrane can be blocked by rmhTNF partly, and the effect of inhibiting proliferation and activating apoptosis on A-549 cells is a result of depression of the K+ channel.

16.
Ying Yong Sheng Tai Xue Bao ; 14(7): 1073-80, 2003 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-14587325

RESUMO

Five typical stations in the Changjiang River estuary and adjacent waters of the East China Sea, were chosen as the sites to study phytoplankton growth and microzooplankton ingestion by on-deck-incubation dilution experiment from 25th April to 25th May 2002. The results showed that microzooplankton ingestion was a key process for controlling red tide event. Strombidium sulcatum, Noctiluca scintillans and Mesodinium robudium were dominant microzooplankton species. In this study, the ingestion rate of microzooplankton ranged from 0.28 to 1.13 d-1; ingestion pressure on percentage of phytoplankton standing crop ranged from 35.14% to 811.69%; ingestion pressure on percentage of potential production ranged from 74.04% to 203.25%; and ingestion rate of phytoplankton carbon ranged from 9.58 to 97.91 C.L-1.d-1. The microzooplankton grazing rate, ingestion pressure on percentage of phytoplankton standing crop, and ingestion rate of phytoplankton carbon were higher near coastal area, but lower at open sea, and the microzooplankton ingestion pressure on percentage of phytoplankton potential production was no the contrary. Compared with the similar studies around the world, the ingestion pressure of microzooplankton in the East China Sea was at a higher level. The primary deduction was that Strombidium was the key microzooplankton species on controlling Prorocentrum dentatum, the most important red tide species in the East China Sea.


Assuntos
Dinoflagelados/crescimento & desenvolvimento , Ecossistema , Proliferação Nociva de Algas , Fitoplâncton/crescimento & desenvolvimento , Água do Mar , Zooplâncton/fisiologia , Animais , China , Oceanos e Mares , Rios , Estações do Ano
17.
Ying Yong Sheng Tai Xue Bao ; 14(7): 1147-50, 2003 Jul.
Artigo em Chinês | MEDLINE | ID: mdl-14587340

RESUMO

Studies on the distribution and germination of Alexandrium sp. (A. tamarense + A. catenella) cysts in coastal areas of Southeast China showed that the cysts were only found at X1 and X2 of Xiamen Harbor, whose density was quite low (0.4 ind.g-1). In Guangxi, the cysts were found at G2 station, with a density of 2.5 ind.g-1. There were cysts at three stations at Minjiang River estuary. The density reaches maximum value at 4-6 cm sediment of M4 station, up to 6 ind.g-1. In Changjiang River estuary, the cysts distributed widely and had the largest density, up to 23.2 ind.g-1 at 8-10 cm sediment of DG-26 station. The distribution of Alexandrium sp.cysts was relevant to sediment type, sedimentation rate and current. Light had no effect on germination. With increasing temperature, germination and survival rates also increased, while the germination time decreased. Anoxia (0.01 mg O2.L-1) inhibited germination completely. Alexandrium sp. cysts could germinate throughout the year under favorable conditions.


Assuntos
Dinoflagelados/crescimento & desenvolvimento , Rios , Água do Mar , China , Sedimentos Geológicos , Luz , Oceanos e Mares , Oxigênio , Temperatura , Movimentos da Água
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