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1.
Nutr Rev ; 2023 Oct 31.
Artigo em Inglês | MEDLINE | ID: mdl-37930102

RESUMO

CONTEXT: Although the nutritional composition of organic food has been thoroughly researched, there is a dearth of published data relating to its impact on human health. OBJECTIVE: This systematic review aimed to examine the association between organic food intake and health effects, including changes in in vivo biomarkers, disease prevalence, and functional changes. DATA SOURCES: PubMed, EMBASE, Web of Science, the Cochrane Library, and ClinicalTrials.gov were searched from inception through Nov 13, 2022. DATA EXTRACTION: Both observational and interventional studies conducted in human populations were included, and association between level of organic food intake and each outcome was quantified as "no association," "inconsistent," "beneficial correlation/harmful correlation," or "insufficient". For outcomes with sufficient data reported by at least 3 studies, meta-analyses were conducted, using random-effects models to calculate standardized mean differences. DATA ANALYSIS: Based on the included 23 observational and 27 interventional studies, the association between levels of organic food intake and (i) pesticide exposure biomarker was assessed as "beneficial correlation," (ii) toxic metals and carotenoids in the plasma was assessed as "no association," (iii) fatty acids in human milk was assessed as "insufficient," (iv) phenolics was assessed as "beneficial", and serum parameters and antioxidant status was assessed as "inconsistent". For diseases and functional changes, there was an overall "beneficial" association with organic food intake, and there were similar findings for obesity and body mass index. However, evidence for association of organic food intake with other single diseases was assessed as "insufficient" due to the limited number and extent of studies. CONCLUSION: Organic food intake was found to have a beneficial impact in terms of reducing pesticide exposure, and the general effect on disease and functional changes (body mass index, male sperm quality) was appreciable. More long-term studies are required, especially for single diseases. SYSTEMATIC REVIEW REGISTRATION: PROSPERO registration no. CRD42022350175.

2.
Front Microbiol ; 14: 1225469, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37621401

RESUMO

Introduction: African swine fever (ASF) is an acute and highly contagious disease and its pathogen, the African swine fever virus (ASFV), threatens the global pig industry. At present, management of ASF epidemic mainly relies on biological prevention and control methods. Moreover, due to the large genome of ASFV, only half of its genes have been characterized in terms of function. Methods: Here, we evaluated a previously uncharacterized viral gene, L60L. To assess the function of this gene, we constructed a deletion strain (SY18ΔL60L) by knocking out the L60L gene of the SY18 strain. To evaluate the growth characteristics and safety of the SY18ΔL60L, experiments were conducted on primary macrophages and pigs, respectively. Results: The results revealed that the growth trend of the recombinant strain was slower than that of the parent strain in vitro. Additionally, 3/5 (60%) pigs intramuscularly immunized with a 105 50% tissue culture infectious dose (TCID50) of SY18ΔL60L survived the 21-day observation period. The surviving pigs were able to protect against the homologous lethal strain SY18 and survive. Importantly, there were no obvious clinical symptoms or viremia. Discussion: These results suggest that L60L could serve as a virulence- and replication-related gene. Moreover, the SY18ΔL60L strain represents a new recombinant live-attenuated ASFV that can be employed in the development of additional candidate vaccine strains and in the elucidation of the mechanisms associated with ASF infection.

3.
Viruses ; 15(4)2023 03 27.
Artigo em Inglês | MEDLINE | ID: mdl-37112838

RESUMO

African swine fever (ASF) is a viral haemorrhagic disease found in domestic and wild boars caused by the African swine fever virus (ASFV). A highly virulent strain was used to evaluate the efficacy of newly developed vaccine candidates. The ASFV strain SY18 was isolated from the first ASF case in China and is virulent in pigs of all ages. To evaluate the pathogenesis of ASFV SY18 following intraoral (IO) and intranasal (IN) infections, a challenge trial was conducted in landrace pigs, with intramuscular (IM) injection as a control. The results showed that the incubation period of IN administration with 40-1000 50 % tissue culture infective dose (TCID50) was 5-8 days, which was not significantly different from that of IM inoculation with 200 TCID50. A significantly longer incubation period, 11-15 days, was observed in IO administration with 40-5000 TCID50. Clinical features were similar among all infected animals. Symptoms, including high fever (≥40.5 °C), anorexia, depression, and recumbency, were observed. No significant differences were detected in the duration of viral shedding during fever. There was no significant difference in disease outcome, and all animals succumbed to death. This trial showed that IN and IO infections could be used for the efficacy evaluation of an ASF vaccine. The IO infection model, similar to that of natural infection, is highly recommended, especially for the primary screening of candidate vaccine strains or vaccines with relatively weak immune efficacy, such as live vector vaccines and subunit vaccines.


Assuntos
Vírus da Febre Suína Africana , Febre Suína Africana , Vacinas Virais , Animais , Genótipo , Sus scrofa , Suínos , Vacinas Atenuadas
4.
Front Nutr ; 9: 1040321, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36313110

RESUMO

The triacylglycerols (TAGs) of medium- and long-chain triacylglycerols (MLCT) and di-unsaturated fatty acyl-palmitoyl-glycerols (UPU) in human milk provide better nutritional effects, and should be prioritized as crucial focuses on neonatal nutrition research. However, little has been done on the influences of the lactation stage and regional diversity on MLCT and UPU. In this study, we collected 204 human milk samples during colostrum, 1st and 4th month from the north (Baotou), central (Beijing), east (Jinan), southwest (Kunming), southeast (Shenzhen), and northwest (Xining) regions of China. There were 122 species of TAGs detected with UPLC-Q-TOF-MS, including 60 kinds of MLCT and 15 kinds of UPU. The MLCT and UPU type TAGs in human milk were ~27 and ~38%, respectively. The sum content of MLCT and UPU in human milk was stable. Compared to the regional diversity, lactation stages showed more obvious influences on MLCT and UPU composition. Moreover, a summary of TAG studies indicated that Chinese human milk showed a higher ratio of O-P-L to O-P-O than in western countries.

5.
Nutrients ; 14(17)2022 Sep 03.
Artigo em Inglês | MEDLINE | ID: mdl-36079904

RESUMO

Breast milk is an unparalleled food for infants, as it can meet almost all of their nutritional needs. Breast milk in the first month is an important source of acquired immunity. However, breast milk protein may vary with the stage of lactation. Therefore, the aim of this study was to use a data-independent acquisition approach to determine the differences in the proteins of breast milk during different lactation periods. The study samples were colostrum (3-6 days), transitional milk (7-14 days), and mature milk (15-29 days). The results identified a total of 2085 different proteins, and colostrum contained the most characteristic proteins. Protein expression was affected by the lactation stage. The proteins expressed in breast milk changed greatly between day 3 and day 14 and gradually stabilized after 14 days. The expression levels of lactoferrin, immunoglobulin, and clusterin were the highest in colostrum. CTP synthase 1, C-type lectin domain family 19 member A, secretoglobin family 3A member 2, trefoil factor 3 (TFF3), and tenascin were also the highest in colostrum. This study provides further insights into the protein composition of breast milk and the necessary support for the design and production of infant formula.


Assuntos
Leite Humano , Proteômica , Aleitamento Materno , Colostro , Feminino , Humanos , Lactente , Lactação/metabolismo , Leite Humano/metabolismo , Gravidez
6.
Front Microbiol ; 13: 929202, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35910614

RESUMO

In contrast to dog-associated human rabies cases decline year by year due to the rabies vaccination coverage rates increase in China, ferret badger (FB, Melogale moschata)-associated human rabies cases emerged in the 1990s, and are now an increasingly recognized problem in southeast China. To investigate epidemiology, temporal evolution dynamics, transmission characterization, and pathogenicity of FB-associated rabies viruses (RABVs), from 2008 to 2018, we collected 3,622 FB brain samples in Jiangxi and Zhejiang Province, and detected 112 RABV isolates. Four FB-related lineages were identified by phylogenetic analysis (lineages A-D), the estimated Times to Most Recent Common Ancestor were 1941, 1990, 1937, and 1997 for lineages A-D, respectively. Furthermore, although no FB-associated human rabies case has been reported there apart from Wuyuan area, FB-RABV isolates are mainly distributed in Jiangxi Province. Pathogenicity of FB-RABVs was assessed using peripheral inoculation in mice and in beagles with masseter muscles, mortality-rates ranging from 20 to 100% in mice and 0 to 20% in beagles in the groups infected with the various isolates. Screening of sera from humans with FB bites and no post-exposure prophylaxis to rabies revealed that five of nine were positive for neutralizing antibodies of RABV. All the results above indicated that FB-RABV variants caused a lesser pathogenicity in mice, beagles, and even humans. Vaccination in mice suggests that inactivated vaccine or recombinant subunit vaccine products can be used to control FB-associated rabies, however, oral vaccines for stray dogs and wildlife need to be developed and licensed in China urgently.

7.
Front Nutr ; 9: 804880, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35757267

RESUMO

Human breastmilk, the ideal food for healthy infants, naturally contains a high concentration of medium-chain fatty acids (MCFAs, about 15% of total fatty acids). MCFAs are an important energy source for infants due to their unique digestive and metabolic properties. MCFA-enriched oils are widely used in an infant formula, especially the formula produced for preterm infants. Recently, there has been a growing interest in the triglyceride structure of MCFAs in human milk, their metabolism, and their effects on infant health. This study summarized the MCFA composition and structure in both human milk and infant formula. Recent studies on the nutritional effects of MCFAs on infant gut microbiota have been reviewed. Special attention was given to the MCFAs digestion and metabolism in the infants. This paper aims to provide insights into the optimization of formulations to fulfill infant nutritional requirements.

8.
J Virol ; 95(23): e0119921, 2021 11 09.
Artigo em Inglês | MEDLINE | ID: mdl-34495696

RESUMO

African swine fever (ASF) is a severe hemorrhagic infectious disease in pigs caused by African swine fever virus (ASFV), leading to devastating economic losses in epidemic regions. Its control currently depends on thorough culling and clearance of the diseased and surrounding suspected pigs. An ASF vaccine has been extensively explored for years worldwide, especially in hog-intensive areas where it is highly desired, but it is still unavailable for numerous reasons. Here, we report another ASF vaccine candidate, named SY18ΔI226R, bearing a deletion of the I226R gene with a replacement of an enhanced green fluorescent protein (eGFP) expression cassette at the right end of the viral genome. This deletion results in the complete loss of virulence of SY18 as the gene-deleted strain does not cause any clinical symptoms in all pigs inoculated with a dosage of either 104.0 or 107.0 50% tissue culture infective doses (TCID50). Apparent viremia with a gradual decline was monitored, while virus shedding was detected only occasionally in oral or anal swabs. ASFV-specific antibody appeared at 9 days postinoculation. After intramuscular challenge with its parental strain ASFV SY18 at 21 days postinoculation, all the challenged pigs survived, without obvious febrile or abnormal clinical signs. No viral DNA could be detected upon the dissection of any tissue when viremia disappeared. These results indicated that SY18ΔI226R is safe in swine and elicits robust immunity to virulent ASFV infection. IMPORTANCE Outbreaks of African swine fever have resulted in devastating losses to the swine industry worldwide, but there is currently no commercial vaccine available. Although several vaccine candidates have been reported, none has been approved for use for several reasons, especially ones concerning biosafety. Here, we identified a new undescribed functional gene, I226R. When deleted from the ASFV genome, the virus completely loses its virulence in swine. Importantly, pigs infected with this gene-deleted virus were resistant to infection by intramuscular challenge with 102.5 or 104.0 TCID50 of its virulent parental virus. Furthermore, the nucleic acid of the gene-deleted virus and its virulent parental virus was rarely detected from oral or anal swabs. Viruses could not be detected in any tissues after necropsy when viremia became negative, indicating that robust immunity was achieved. Therefore, SY18ΔI226R is a novel, ideal, and efficacious vaccine candidate for genotype II ASF.


Assuntos
Vírus da Febre Suína Africana/genética , Vírus da Febre Suína Africana/imunologia , Febre Suína Africana/imunologia , Deleção de Genes , Genoma Viral , Febre Suína Africana/patologia , Febre Suína Africana/prevenção & controle , Animais , DNA Viral , Genes Virais/genética , Genótipo , Análise de Sequência , Suínos , Vacinas Virais/imunologia , Viremia/genética , Virulência/genética
9.
Viruses ; 13(4)2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33916308

RESUMO

Mink refractory diarrhea is a seasonal disease that occurs in many mink farms in China. Mink circovirus (MiCV) has been recognized as the causative agent of the disease. The aim of the study was to develop a subunit vaccine against mink refractory diarrhea. A recombinant baculovirus strain expressing the capsid protein was constructed using the baculovirus expression vector system (BEVS). A subunit vaccine was developed based on the capsid protein with appropriate adjuvant. Then, a field trial was carried out in two districts in order to evaluate the efficiency of the subunit vaccine. The field trial indicated that in total, only 1.8% of the minks developed typical diarrhea in the vaccinated group compared with 74.5% in the control group. The vaccination could significantly reduce the infection rate of MiCV among the mink herds and could restrain the virus' shedding from feces. Furthermore, the vaccinated group had a higher average litter size in the following year compared to the control group. Collectively, the results indicated that the subunit vaccine based on the capsid protein can provide reliable protection against MiCV infection.


Assuntos
Anticorpos Antivirais/sangue , Baculoviridae/genética , Proteínas do Capsídeo/genética , Infecções por Circoviridae/prevenção & controle , Infecções por Circoviridae/veterinária , Circovirus/imunologia , Diarreia/prevenção & controle , Vison/virologia , Vacinas Virais/imunologia , Animais , Capsídeo/imunologia , Capsídeo/metabolismo , Proteínas do Capsídeo/imunologia , China , Infecções por Circoviridae/imunologia , Circovirus/genética , Diarreia/virologia , Feminino , Masculino , Vacinas de Subunidades Antigênicas/imunologia , Vacinas Virais/administração & dosagem
10.
Viruses ; 14(1)2021 12 29.
Artigo em Inglês | MEDLINE | ID: mdl-35062257

RESUMO

African swine fever virus (ASFV) is the causative agent of African swine fever (ASF) which reaches up to 100% case fatality in domestic pigs and wild boar and causes significant economic losses in the swine industry. Lack of knowledge of the function of ASFV genes is a serious impediment to the development of the safe and effective vaccine. Herein, I267L was identified as a relative conserved gene and an early expressed gene. A recombinant virus (SY18ΔI267L) with I267L gene deletion was produced by replacing I267L of the virulent ASFV SY18 with enhanced green fluorescent protein (EGFP) cassette. The replication kinetics of SY18ΔI267L is similar to that of the parental isolate in vitro. Moreover, the doses of 102.0 TCID50 (n = 5) and 105.0 TCID50 (n = 5) SY18ΔI267L caused virulent phenotype, severe clinical signs, viremia, high viral load, and mortality in domestic pigs inoculated intramuscularly as the virulent parental virus strain. Therefore, the deletion of I267L does not affect the replication or the virulence of ASFV. Utilizing the fluorescent-tagged virulence deletant can be easy to gain a visual result in related research such as the inactivation effect of some drugs, disinfectants, extracts, etc. on ASFV.


Assuntos
Vírus da Febre Suína Africana/genética , Vírus da Febre Suína Africana/fisiologia , Fatores de Virulência/genética , Replicação Viral/genética , Febre Suína Africana/virologia , Animais , Anticorpos Antivirais , Deleção de Genes , Fenótipo , Sus scrofa , Suínos , Doenças dos Suínos/virologia , Proteínas Virais/genética , Vacinas Virais/imunologia , Viremia , Virulência/genética
12.
Front Microbiol ; 10: 1004, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31156571

RESUMO

African swine fever virus (ASFV), the etiological agent of African swine fever (ASF), a hemorrhagic fever of domestic pigs, has devastating consequences for the pig farming industry. More than 1,000,000 pigs have been slaughtered since 3 August 2018 in China. However, vaccines or drugs for ASF have yet to be developed. As such, a rapid test that can accurately detect ASFV on-site is important to the timely implementation of control measures. In this study, we developed a rapid test that combines recombinase polymerase amplification (RPA) of the ASFV p72 gene with lateral flow detection (LFD). Results showed that the sensitivity of recombinase polymerase amplification with lateral flow dipstick (RPA-LFD) for ASFV was 150 copies per reaction within 10 min at 38°C. The assay was highly specific to ASFV and had no cross-reactions with other porcine viruses, including classical swine fever virus (CSFV). A total of 145 field samples were examined using our method, and the agreement of the positive rate between RPA-LFD (10/145) and real-time PCR (10/145) was 100%. Overall, RPA-LFD provides a novel alternative for the simple, sensitive, and specific identification of ASFV and showed potential for on-site ASFV detection.

13.
Vaccine ; 37(16): 2224-2231, 2019 04 10.
Artigo em Inglês | MEDLINE | ID: mdl-30878247

RESUMO

In China, cats cause about 5% of human rabies cases. Rabies control in cats plays a role in achieving the ultimate goal of elimination of dog rabies-mediated human deaths. However, there is no cat-specific rabies vaccine in China yet. In this study, we constructed a recombinant rabies vaccine by using a felid herpesvirus 1 (FHV-1) isolate, and deleted the gI/E in the FHV-1 and replaced the region with a glycoprotein (G) of rabies virus (RABV) strain BD06 through homologous recombination. The recombinant virus FHV-RVG was recovered and purified, and the expression of RABV glycoprotein was verified by indirect immunofluorescent assay. For potency in cats, each animal was inoculated intranasally with 1 ml FHV-RVG at 106.5 TCID50. Blood samples were collected at defined intervals for antibody titration. The animals were challenged by herpes and rabies after completion of vaccination on day 180 and day 194, respectively. Our results demonstrated all vaccinated cats generated antibodies against both FHV-1 and RABV, and reached an arbitrary protective titer > 0.5 IU/ml for rabies viral neutralizing antibody (VNA) by day 14 post inoculation (dpi) and titer peaked on 30 dpi with VNA at 24.5 ±â€¯10.23 IU/ml. All vaccinated cats presented no clinical signs of FHV-1 infection and survived rabies challenge, while the control cats had severe rhinotracheitis and died from rabies after challenge. All this demonstrated that the FHV-based recombinant vaccine is effective in protection against both FHV-1 and RABV infections.


Assuntos
Vetores Genéticos , Vacina Antirrábica/imunologia , Vírus da Raiva/imunologia , Raiva/imunologia , Varicellovirus , Animais , Anticorpos Neutralizantes , Anticorpos Antivirais/sangue , Anticorpos Antivirais/imunologia , Doenças do Gato/imunologia , Doenças do Gato/prevenção & controle , Gatos , Linhagem Celular , Cães , Expressão Gênica , Genes Reporter , Vetores Genéticos/genética , Recombinação Homóloga , Humanos , Imunização , Testes de Neutralização , Raiva/prevenção & controle , Vacina Antirrábica/administração & dosagem , Vacina Antirrábica/genética , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/imunologia , Varicellovirus/genética
14.
Arch Virol ; 159(8): 2059-67, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24643334

RESUMO

Ferret badger (FB) rabies viruses JX09-17(fb), JX09-18 and JX10-37 were isolated from three different regions in Jiangxi province, China, in 2009 and 2010. The complete nucleotide sequence identity between these three isolates was 87-93 %. Compared with the other Chinese rabies virus isolates and vaccine strains, 101 substitutions (53 in JX10-37, 23 in JX09-17(fb) and 25 in JX09-18) in the five structural proteins were observed, and 47 of these substitutions (27 in JX10-37, 14 in JX09-17(fb) and 6 in JX09-18) were unique among lyssaviruses. Amino acid substitutions of S231 and Q333 were noted respectively in the G protein antigenic site I of JX10-37 and site III in JX09-17(fb). Phylogenetic analysis showed that JX09-17(fb) is rooted within the China I lineage, JX09-18 is in China II, and JX10-37 is independent. Evolutionary analysis and comparative sequence data indicate that isolate JX10-37 is a variant virus that diverged from canine rabies viruses around 1933 (range 1886-1963).


Assuntos
Furões/virologia , Vírus da Raiva/genética , Vírus da Raiva/isolamento & purificação , Raiva/veterinária , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , China , Doenças do Cão/transmissão , Doenças do Cão/virologia , Cães , Dados de Sequência Molecular , Filogenia , Raiva/virologia , Vírus da Raiva/classificação , Proteínas Virais/genética
15.
Arch Virol ; 159(6): 1481-6, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-24352434

RESUMO

A canine rabies virus, Shaanxi-HZ-6, was isolated in Shaanxi Province, China, in 2009. Its genome has been completely sequenced and found to be closely related to the China I rabies virus strains widely circulating in China. The genomic length was 11,923 base pairs, and the overall organization of the genome was similar to that of other rabies virus isolates. Compared with isolates CQ92 and J, 84 amino acid substitutions (7 in the N gene, 15 in P, 6 in M, 25 in G, 31 in L) were observed in strain Shaanxi-HZ-6. Amino acid substitutions of R264H and V332I were noted in the G protein antigenic site I and site III, respectively. Residue 333 of the G protein, which is considered to be associated with pathogenicity, was Arg in Shaanxi-HZ-6. These and other substitutions may help provide an explanation why the China I lineage strain maintains its prevalence in China.


Assuntos
Doenças do Cão/virologia , Genoma Viral , RNA Viral/genética , Vírus da Raiva/genética , Vírus da Raiva/isolamento & purificação , Raiva/veterinária , Análise de Sequência de DNA , Substituição de Aminoácidos , Animais , China , Análise por Conglomerados , Cães , Dados de Sequência Molecular , Filogenia , Raiva/virologia , Vírus da Raiva/classificação , Homologia de Sequência , Proteínas Virais/genética
16.
Integr Biol (Camb) ; 4(10): 1155-63, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22907590

RESUMO

Polymerase chain reaction (PCR) has become a standard and important molecular biological technique with numerous applications in genetic analysis, forensics and in vitro diagnostics. Since its invention in the 1980s, there has been dramatic performance improvement arising from long-lasting efforts to optimize amplification conditions in both academic studies and commercial applications. More recently, a range of nanometer-sized materials including metal nanoparticles, semiconductor quantum dots, carbon nanomaterials and polymer nanoparticles, have shown unique effects in tuning amplification processes of PCR. It is proposed that these artificial nanomaterials mimic protein components in the natural DNA replication machinery in vivo. These so-called nanomaterials-assisted PCR (nanoPCR) strategies shed new light on powerful PCR with unprecedented sensitivity, selectivity and extension rate. In this review, we aim to summarize recent progress in this direction and discuss possible mechanisms for such performance improvement and potential applications in genetic analysis (particularly gene typing and haplotyping) and diagnostics.


Assuntos
Nanotecnologia/métodos , Reação em Cadeia da Polimerase/métodos , Dano ao DNA , Primers do DNA/genética , Técnicas Genéticas , Genótipo , Ouro/química , Haplótipos , Humanos , Nanopartículas Metálicas/química , Pontos Quânticos , Reprodutibilidade dos Testes , Semicondutores , Análise de Sequência de DNA/métodos , Telomerase/metabolismo
17.
Nanoscale ; 3(9): 3888-92, 2011 Sep 01.
Artigo em Inglês | MEDLINE | ID: mdl-21829836

RESUMO

Investigation into the interactions between graphene oxide (GO) and biomolecules is very important for broad applications of GO in bioassay and bioanalysis. In this work, we describe the interactions between double-stranded DNA (dsDNA) and GO. We demonstrated that dsDNA can bind to GO forming complexes (dsDNA/GO) in the presence of certain salts, which protects dsDNA from being enzymatically digested. On the other hand, we found that a nonionic surfactant, such as triton X-100, can block the formation of dsDNA/GO complexes, so that the enzymatic digestion of dsDNA is restored. These results lead us to believe that the reason for GO protecting dsDNA from enzymatic digestion is the formation of dsDNA/GO complexes hindering the access of DNA enzymes to dsDNA, rather than direct inactivation of the DNA enzymes.


Assuntos
DNA/metabolismo , Enzimas/metabolismo , Grafite/química , Óxidos/química , Adsorção , DNA/química , Desoxirribonuclease I/metabolismo , Desoxirribonucleases de Sítio Específico do Tipo II/metabolismo , Endodesoxirribonucleases/metabolismo , Nanoestruturas/química , Octoxinol/química
18.
Small ; 5(22): 2597-600, 2009 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-19722185

RESUMO

A new gold-nanoparticle (AuNP)-based strategy to dynamically modulate the activity of DNA polymerases and realize a hot-start (HS)-like effect in the polymerase chain reaction (PCR) is reported, which effectively prevents unwanted nonspecific amplification and improves the performance of PCRs. A high-fidelity Pfu DNA polymerase is employed as the model system. Interestingly, AuNPs inactivate the polymerase activity of Pfu at low temperature, thus resembling an antibody-based HS PCR. This inhibition effect of AuNPs is demonstrated for the preamplification polymerization activity of the PCR, which largely suppresses nonspecific amplification at temperatures between 30 and 60 degrees C and leads to highly specific and sensitive PCR amplification with Pfu. Significantly, the fidelity of Pfu is not sacrificed in the presence of AuNPs. Therefore, this AuNP-based HS strategy provides a straightforward and potentially versatile approach to realize high-performance PCR amplification.


Assuntos
DNA Polimerase Dirigida por DNA/química , DNA Polimerase Dirigida por DNA/ultraestrutura , Ouro/química , Nanopartículas/química , Nanopartículas/ultraestrutura , Reação em Cadeia da Polimerase/métodos , Teste de Materiais
19.
J Nanosci Nanotechnol ; 9(4): 2247-55, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19437962

RESUMO

Nanomaterials, with their diverse dimensions, shapes and surface functional groups, may interact with biomolecules in various ways. In this paper, we reviewed recent advances on the research of the effect of nanomaterials on biomolecular reactions and the use of nano-bio-complexes in biosensors. Much evidence has clearly indicated that nanomaterials are excellent matrixes for the immobilization of enzymes and such complexes often exhibits even higher activities than native enzymes. Consequently, a large amount of highly sensitive biosensors have been developed based on such nano-bio-complexes. We also stressed the importance of nanomaterials on the reactions of nucleic acids. By exploiting the interactions between AuNPs and DNA, several groups have developed a series of novel biosensors for the detection of DNA target and other biologically important molecules. While the state-of-the-art researches are mainly focused on the study of one nanomaterial and one biomolecule, there has been evidence that integration of nano-bio-complexes might lead to much more interesting findings. For example, nanomaterials have been found to exert great impact on complicated systems such as PCR. One might expect that the realization of highly cooperated nano-bio-machines that comprise of different nanomaterials and different biomolecules would lead to highly promising diagnostic tools both in-vivo and in-vitro.


Assuntos
Técnicas Biossensoriais/métodos , Enzimas Imobilizadas/metabolismo , Nanoestruturas , Ácidos Nucleicos/metabolismo , Técnicas Biossensoriais/tendências , Enzimas Imobilizadas/química , Nanoestruturas/química , Nanotecnologia/métodos , Nanotecnologia/tendências , Ácidos Nucleicos/química
20.
Nanotechnology ; 19(25): 255101, 2008 Jun 25.
Artigo em Inglês | MEDLINE | ID: mdl-21828643

RESUMO

Gold nanoparticles (AuNPs) have been proven to be able to improve the specificity or increase the efficiency of a polymerase chain reaction (PCR) when a suitable amount of AuNPs was used. However, there is still a lack of systematic evaluation of AuNPs in real-time PCR. In this study, DNA degradation and the fluorescence quenching effect of AuNPs were first tested in real-time PCR. Then two different kinds of Taq DNA polymerase, native and recombinant Taq polymerase, were employed to evaluate the AuNPs' effect on the threshold cycle (C(T)) values, standard curves and melting curves in real-time PCR. Different ratios of the amount of native Taq DNA polymerase to the amount of AuNPs were also tested. It was found that AuNPs could be applied in real-time PCR with correlation coefficient R(2)>0.989. The combination of 2.09 nM AuNPs with 3.75 U of native Taq DNA polymerase could make the amplification curves shift to the left and enhance the efficiency of the real-time PCR (0.628 39 without AuNPs compared with 0.717 89 with 2.09 nM AuNPs), thus enabling faster detection in comparison with those of control samples. However, no improvement ability of AuNPs was found in real-time PCR based on recombinant rTaq DNA polymerase. Besides, the results suggest that a complex interaction exists between AuNPs and native Taq DNA polymerase.

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