Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
Mais filtros








Base de dados
Intervalo de ano de publicação
1.
J Anim Sci Biotechnol ; 15(1): 138, 2024 Oct 10.
Artigo em Inglês | MEDLINE | ID: mdl-39385285

RESUMO

BACKGROUND: Aflatoxin B1 (AFB1) is a prevalent contaminant in agricultural products, presenting significant risks to animal health. CotA laccase from Bacillus licheniformis has shown significant efficacy in degrading mycotoxins in vitro test. The efficacy of Bacillus CotA laccase in animals, however, remains to be confirmed. A 2 × 2 factorial design was used to investigate the effects of Bacillus CotA laccase level (0 or 1 U/kg), AFB1 challenge (challenged or unchallenged) and their interactions on ducks. The purpose of this study was to evaluate the efficacy of Bacillus CotA laccase in alleviating AFB1 toxicosis of ducks. RESULTS: Bacillus CotA laccase alleviated AFB1-induced declines in growth performance of ducks accompanied by improved average daily gain (ADG) and lower feed/gain ratio (F/G). Bacillus CotA laccase ameliorated AFB1-induced gut barrier dysfunctions and inflammation testified by increasing the jejunal villi height/crypt depth ratio (VH/CD) and the mRNA expression of tight junction protein 1 (TJP1) and zonula occluden-1 (ZO-1) as well as decreasing the expression of inflammation-related genes in the jejunum of ducks. Amino acid metabolome showed that Bacillus CotA laccase ameliorated AFB1-induced amino acid metabolism disorders evidenced by increasing the level of glutamic acid in serum and upregulating the expression of amino acid transport related genes in jejunum of ducks. Bacillus CotA laccase ameliorated AFB1-induced liver injury testified by suppressing oxidative stress, inhibiting apoptosis, and downregulating the expression of hepatic metabolic enzyme related genes of ducks. Moreover, Bacillus CotA laccase degraded AFB1 in digestive tract of ducks, resulting in the reduced absorption level of AFB1 across intestinal epithelium testified by the decreased level of AFB1-DNA adduct in the liver, and the reduced content of AFB1 residues in liver and feces of ducks. CONCLUSIONS: Bacillus CotA laccase effectively improved the growth performance, intestinal health, amino acid metabolism and hepatic aflatoxin metabolism of ducks fed AFB1 diets, highlighting its potential as an efficient and safe feed enzyme for AFB1 degradation in animal production.

2.
Lab Anim ; 58(5): 463-469, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39301804

RESUMO

Animal research often involves measuring the outcomes of interest multiple times on the same animal, whether over time or for different exposures. These repeated outcomes measured on the same animal are correlated due to animal-specific characteristics. While this repeated measures data can address more complex research questions than single-outcome data, the statistical analysis must take into account the study design resulting in correlated outcomes, which violate the independence assumption of standard statistical methods (e.g. a two-sample t-test, linear regression). When standard statistical methods are incorrectly used to analyze correlated outcome data, the statistical inference (i.e. confidence intervals and p-values) will be incorrect, with some settings leading to null findings too often and others producing statistically significant findings despite no support for this in the data. Instead, researchers can leverage approaches designed specifically for correlated outcomes. In this article, we discuss common study designs that lead to correlated outcome data, motivate the intuition about the impact of improperly analyzing correlated outcomes using methods for independent data, and introduce approaches that properly leverage correlated outcome data.


Assuntos
Projetos de Pesquisa , Animais , Modelos Estatísticos , Interpretação Estatística de Dados , Experimentação Animal/estatística & dados numéricos
3.
Artigo em Inglês | MEDLINE | ID: mdl-39167521

RESUMO

Precise control of strength is of significant importance in upper limb functional rehabilitation. Understanding the neuro-muscular response in strength regulation can help optimize the rehabilitation prescriptions and facilitate the relative training process for recovery control. This study aimed to investigate the inherent characteristics of neural-muscular activity during dynamic hand strength adjustment. Four dynamic grip force tracking modes were set by manipulating different magnitude and speed of force variations, and thirteen healthy young individuals took participation in the experiment. Electroencephalography were recorded in the contralateral sensorimotor cortex area, as well as the electromyography from the first dorsal interosseous muscle were collected synchronously. The metrics of the Event-related desynchronization, the electromyography stability index, and the force variation, were used to represent the corresponding cortical neural responses, muscle contraction activities, and the level of strength regulation, respectively; and further neuro-muscular coupling between the sensorimotor cortex and the first dorsal interosseous muscle was investigated by transfer entropy analysis. The results indicated a strong relationship that the increase of force regulation demand would result in a force variation increase as well as a stability reduction in muscle motor unit output. Meanwhile, the intensity of neural response increased in both the α and ß frequency bands. As the force regulation demand increased, the strength of bidirectional transfer entropy showed a clear shift from ß to the γ frequency band, which facilitate rapid integration of dynamic strength compensation to adapt to motor task changes.


Assuntos
Adaptação Fisiológica , Eletroencefalografia , Eletromiografia , Força da Mão , Voluntários Saudáveis , Músculo Esquelético , Córtex Sensório-Motor , Humanos , Força da Mão/fisiologia , Masculino , Músculo Esquelético/fisiologia , Adulto Jovem , Adaptação Fisiológica/fisiologia , Córtex Sensório-Motor/fisiologia , Adulto , Feminino , Contração Muscular/fisiologia , Entropia , Algoritmos , Ritmo beta/fisiologia , Ritmo alfa/fisiologia
4.
Int J Mol Sci ; 25(12)2024 Jun 12.
Artigo em Inglês | MEDLINE | ID: mdl-38928160

RESUMO

Aflatoxin B1 (AFB1) contamination is a serious threat to nutritional safety and public health. The CotA-laccase from Bacillus licheniformis ANSB821 previously reported by our laboratory showed great potential to degrade AFB1 without redox mediators. However, the use of this CotA-laccase to remove AFB1 in animal feed is limited because of its low catalytic efficiency and low expression level. In order to make better use of this excellent enzyme to effectively degrade AFB1, twelve mutants of CotA-laccase were constructed by site-directed mutagenesis. Among these mutants, E186A and E186R showed the best degradation ability of AFB1, with degradation ratios of 82.2% and 91.8% within 12 h, which were 1.6- and 1.8-times higher than those of the wild-type CotA-laccase, respectively. The catalytic efficiencies (kcat/Km) of E186A and E186R were found to be 1.8- and 3.2-times higher, respectively, than those of the wild-type CotA-laccase. Then the expression vectors pPICZαA-N-E186A and pPICZαA-N-E186R with an optimized signal peptide were constructed and transformed into Pichia pastoris GS115. The optimized signal peptide improved the secretory expressions of E186A and E186R in P. pastoris GS115. Collectively, the current study provided ideal candidate CotA-laccase mutants for AFB1 detoxification in food and animal feed and a feasible protocol, which was desperately needed for the industrial production of CotA-laccases.


Assuntos
Aflatoxina B1 , Bacillus licheniformis , Proteínas de Bactérias , Lacase , Aflatoxina B1/metabolismo , Bacillus licheniformis/genética , Bacillus licheniformis/metabolismo , Bacillus licheniformis/enzimologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Lacase/metabolismo , Lacase/genética , Mutagênese Sítio-Dirigida , Proteínas Recombinantes/metabolismo , Proteínas Recombinantes/genética , Saccharomycetales
5.
Heliyon ; 9(11): e22388, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38058637

RESUMO

Aflatoxin B1 (AFB1) contamination seriously threatens nutritional safety and common health. Bacterial CotA-laccases have great potential to degrade AFB1 without redox mediators. However, CotA-laccases are limited because of the low catalytic activity as the spore-bound nature. The AFB1 degradation ability of CotA-laccase from Bacillus licheniformis ANSB821 has been reported by a previous study in our laboratory. In this study, a Q441A mutant was constructed to enhance the activity of CotA-laccase to degrade AFB1. After the site-directed mutation, the mutant Q441A showed a 1.73-fold higher catalytic efficiency (kcat/Km) towards AFB1 than the wild-type CotA-laccase did. The degradation rate of AFB1 by Q441A mutant was higher than that by wild-type CotA-laccase in the pH range from 5.0 to 9.0. In addition, the thermostability was improved after mutation. Based on the structure analysis of CotA-laccase, the higher catalytic efficiency of Q441A for AFB1 may be due to the smaller steric hindrance of Ala441 than Gln441. This is the first research to enhance the degradation efficiency of AFB1 by CotA-laccase with site-directed mutagenesis. In summary, the mutant Q441A will be a suitable candidate for highly effective detoxification of AFB1 in the future.

6.
J Cosmet Sci ; 71(2): 91-109, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32271711

RESUMO

Surfactants possess the ability to reduce surface tension at low concentrations, resulting in emulsification, foaming, wetting, and solubilizing. As a versatile industrial material, surfactants can be widely used as additives in the industrial field as different as textile, metal processing, mineral processing, new materials, industrial cleaning, construction, and pharmaceuticals. The most extensive application of surfactants perhaps is in the household and cosmetic industries, such as laundry detergents, dishwashing detergents, facial and body cleansers, and preparation of emulsions and creams. However, the extensive use of detergents, cleaners, and cleansers on skin may cause itching, redness, and dryness termed as surfactant-induced irritation, which is at least, partially due to surfactant penetration into skin. To understand how surfactants penetrate into skin, this review summarizes the penetration models proposed by researchers in the past two decades, including the surfactant monomer penetration model, the surfactant micelle and submicelle penetration model, and the recently proposed surfactant charge density and penetration correlation model that demonstrates the correlation between the surfactant charge density and skin penetration.


Assuntos
Cosméticos , Dermatopatias , Pele , Detergentes , Humanos , Tensoativos
7.
Materials (Basel) ; 12(5)2019 Feb 26.
Artigo em Inglês | MEDLINE | ID: mdl-30813534

RESUMO

Porous α-SiAlON ceramics were fabricated using the camphene-based unidirectional freeze casting method, in which a gradient porous structure was formed as a result of the decreased solidification velocity in the freezing direction. Microstructure, porosity and pore size distribution of different parts of as-prepared samples were examined and compared, and correlated with their mechanical properties. For a given solid loading, the overall pore size and porosity of the top part were greater than those of the bottom part. Interestingly, despite its higher porosity, the flexural strength and fracture toughness of the top part were both higher than those of the bottom part, suggesting that apart from porosity, pore morphology and size affected mechanical properties of as-prepared porous α-SiAlON ceramics.

8.
Phys Chem Chem Phys ; 21(9): 4947-4952, 2019 Feb 27.
Artigo em Inglês | MEDLINE | ID: mdl-30758018

RESUMO

The electrochemical properties of VPO4O as a cathode for Mg batteries were studied by performing first principles calculations. Mg insertion features a plateau at about 2.8 V up to Mg0.5VPO4O and then another plateau at around 2.2 V up to MgVPO4O, with a theoretical capacity of about 154 mA h g-1 and 144 mA h g-1, respectively. MgVPO4O is found to be dynamically stable with the absence of negative frequencies in the phonon density of states. The insertion of one Mg reduced two VO6 units instead of reducing only one VO6 unit. In addition, MgVPO4O shows an energy barrier of about 0.58 eV for Mg-ion vacancy migration along the [111] direction, which is comparable to that of many other cathode materials. Our results indicated that MgVPO4O has the potential to be a promising candidate as a cathode material for Mg batteries.

9.
Genetics ; 210(4): 1317-1328, 2018 12.
Artigo em Inglês | MEDLINE | ID: mdl-30291110

RESUMO

Dealing with physiological stress is a necessity for all organisms, and the pathways charged with this task are highly conserved in Metazoa . Accumulating evidence highlights cell-nonautonomous activation as an important mode of integrating stress responses at the organism level. Work in Caenorhabditis elegans highlighted the importance of such regulation for the unfolded protein response (UPR) and for gene expression downstream of the longevity-associated transcription factor DAF-16 Here we describe a role for the JNK homolog KGB-1 in cell-nonautonomous regulation of these two response modules. KGB-1 protects developing larvae from heavy metals and from protein folding stress (which we found to be independent of canonical UPR pathways), but sensitizes adults to the same stress, further shortening life span under normal conditions. This switch is associated with age-dependent antagonistic regulation of DAF-16 Using transgenic tissue-specific KGB-1 expression or tissue-specific KGB-1 activation we examined the contributions of KGB-1 to gene regulation, stress resistance, and life span. While cell-autonomous contributions were observed, particularly in the epidermis, cell-nonautonomous contributions of neuronal KGB-1 (and also in muscle) were effective in driving intestinal gene induction, age-dependent regulation of intestinal DAF-16, and stress resistance, and did not require KGB-1 expression in the target tissue. Additional genetic analyses revealed requirement for UNC-13 in mediating neuronal contributions, indicating involvement of neurotransmission. Our results expand the role of KGB-1 in stress responses from providing local cellular protection to integrating stress responses at the level of the whole organism.


Assuntos
Proteínas de Caenorhabditis elegans/genética , Fatores de Transcrição Forkhead/genética , Proteínas Quinases JNK Ativadas por Mitógeno/genética , Longevidade/genética , Proteínas de Membrana/genética , Proteínas do Tecido Nervoso/genética , Animais , Animais Geneticamente Modificados , Caenorhabditis elegans/genética , Regulação da Expressão Gênica/genética , Larva/genética , Sistema de Sinalização das MAP Quinases/genética , Estresse Fisiológico/genética , Transmissão Sináptica/genética , Resposta a Proteínas não Dobradas/genética
10.
Cell ; 174(4): 870-883.e17, 2018 08 09.
Artigo em Inglês | MEDLINE | ID: mdl-30057120

RESUMO

The mitochondrial unfolded protein response (UPRmt) can be triggered in a cell-non-autonomous fashion across multiple tissues in response to mitochondrial dysfunction. The ability to communicate information about the presence of mitochondrial stress enables a global response that can ultimately better protect an organism from local mitochondrial challenges. We find that animals use retromer-dependent Wnt signaling to propagate mitochondrial stress signals from the nervous system to peripheral tissues. Specifically, the polyQ40-triggered activation of mitochondrial stress or reduction of cco-1 (complex IV subunit) in neurons of C. elegans results in the Wnt-dependent induction of cell-non-autonomous UPRmt in peripheral cells. Loss-of-function mutations of retromer complex components that are responsible for recycling the Wnt secretion-factor/MIG-14 prevent Wnt secretion and thereby suppress cell-non-autonomous UPRmt. Neuronal expression of the Wnt ligand/EGL-20 is sufficient to induce cell-non-autonomous UPRmt in a retromer complex-, Wnt signaling-, and serotonin-dependent manner, clearly implicating Wnt signaling as a strong candidate for the "mitokine" signal.


Assuntos
Animais Geneticamente Modificados/metabolismo , Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Mitocôndrias/metabolismo , Poliubiquitina/metabolismo , Resposta a Proteínas não Dobradas/fisiologia , Proteínas Wnt/metabolismo , Animais , Animais Geneticamente Modificados/genética , Animais Geneticamente Modificados/crescimento & desenvolvimento , Caenorhabditis elegans/genética , Caenorhabditis elegans/crescimento & desenvolvimento , Proteínas de Caenorhabditis elegans/genética , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Glicoproteínas/genética , Glicoproteínas/metabolismo , Peptídeos e Proteínas de Sinalização Intracelular , Mitocôndrias/genética , Neurônios/citologia , Neurônios/metabolismo , Proteínas de Transporte Vesicular/genética , Proteínas de Transporte Vesicular/metabolismo , Proteínas Wnt/genética
11.
J Allergy Clin Immunol ; 141(3): 927-937, 2018 03.
Artigo em Inglês | MEDLINE | ID: mdl-29103995

RESUMO

BACKGROUND: The contribution of ectopic lymphoid tissues (eLTs) to local immunoglobulin hyperproduction in patients with chronic rhinosinusitis with nasal polyps (CRSwNP) is unclear. OBJECTIVE: We sought to explore the cellular basis, formation mechanisms, and function of eLTs in patients with CRSwNP. METHODS: We graded lymphoid aggregations in sinonasal mucosa and histologically studied their structures. The expression of lymphorganogenic factors and molecules required for immunoglobulin production was measured by using real-time PCR, and their localization was analyzed by means of immunohistochemistry and immunofluorescence. The phenotype of follicular helper T cells was analyzed by performing flow cytometry. Immunoglobulin levels were quantified by using the Bio-Plex assay or ImmunoCAP system. Nasal tissue explants were challenged ex vivo with Dermatophagoides pteronyssinus group 1 (Der p 1), and the expression of Iε-Cµ and Iε-Cγ circle transcripts was detected by using seminested PCR. RESULTS: Increased formation of eLTs with germinal center-like structures was discovered in patients with eosinophilic (20.69%) and noneosinophilic (17.31%) CRSwNP compared with that in patients with chronic rhinosinusitis without nasal polyps (5.66%) and control subjects (3.70%). The presence of eLTs was associated with increased expression of lymphorganogenic and inflammatory chemokines and cytokines, as well as their receptors. The expression of molecules required for immunoglobulin production, generation of follicular helper T cells, and production of IgE in eosinophilic polyps and IgG and IgA in both eosinophilic and noneosinophilic polyps were predominantly upregulated in patients with eLTs. After Der p 1 challenge ex vivo, Iε-Cµ transcript was detected only in eosinophilic polyps with eLTs but not in polyps without eLTs and noneosinophilic polyps. CONCLUSION: eLTs might support local immunoglobulin production and therefore significantly contribute to the development of CRSwNP.


Assuntos
Formação de Anticorpos , Pólipos Nasais , Rinite Alérgica , Sinusite , Estruturas Linfoides Terciárias , Adulto , Doença Crônica , Eosinófilos/imunologia , Eosinófilos/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Pólipos Nasais/imunologia , Pólipos Nasais/patologia , Rinite Alérgica/imunologia , Rinite Alérgica/patologia , Sinusite/imunologia , Sinusite/patologia , Linfócitos T Auxiliares-Indutores/imunologia , Linfócitos T Auxiliares-Indutores/patologia , Estruturas Linfoides Terciárias/imunologia , Estruturas Linfoides Terciárias/patologia
12.
Cell Signal ; 30: 1-8, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27864060

RESUMO

JNK proteins are conserved stress-activated MAP kinases. In C. elegans, the JNK-homolog KGB-1 plays essential roles in protection from heavy metals and protein folding stress. However, the contributions of KGB-1 are age-dependent, providing protection in larvae, but reducing stress resistance and shortening lifespan in adults. Attenuation of DAF-16 was linked to the detrimental contributions of KGB-1 in adults, but its involvement in KGB-1-dependent protection in larvae remains unclear. To characterize age-dependent contributions of KGB-1, we used microarray analysis to measure gene expression following KGB-1 activation either in developing larvae or in adults, achieved by knocking down its negative phosphatase regulator vhp-1. This revealed a robust KGB-1 regulon, most of which consisting of genes induced following KGB-1 activation regardless of age; a smaller number of genes was regulated in an age-dependent manner. We found that the bZIP transcription factor FOS-1 was essential for age-invariant KGB-1-dependent gene induction, but not for age-dependent expression. The latter was more affected by DAF-16, which was further found to be required for KGB-1-dependent cadmium resistance in larvae. Our results identify FOS-1 as a transcriptional activator mediating age-invariant contributions of KGB-1, including a regulatory loop of KGB-1 signaling, but also stress the importance of DAF-16 as a mediator of age-dependent contributions.


Assuntos
Proteínas de Caenorhabditis elegans/metabolismo , Caenorhabditis elegans/metabolismo , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Proteínas Proto-Oncogênicas c-fos/metabolismo , Homologia de Sequência de Aminoácidos , Transativadores/metabolismo , Envelhecimento/genética , Animais , Cádmio/toxicidade , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/genética , Regulação da Expressão Gênica/efeitos dos fármacos , Ontologia Genética , Anotação de Sequência Molecular , Regulon/genética , Transdução de Sinais/efeitos dos fármacos
13.
Sci Rep ; 6: 35178, 2016 10 12.
Artigo em Inglês | MEDLINE | ID: mdl-27731377

RESUMO

Francisella-like endosymbionts (FLEs) with significant homology to Francisella tularensis (γ-proteobacteria) have been characterized in several tick species, whereas knowledge on their distribution and population dynamics in ticks remains meager. Hence, in the current study, we identified a novel Francisella-like endosymbiont (FLEs-Hd) from the tick Haemaphysalis doenitzi and evaluated the putative functions of this symbiont. Results indicated that FLEs-Hd had 100% infection rate and a perfect vertical transmission in H. doenitzi, and that it is distributed in ovaries, malpighian tubules, salivary glands and midguts of the ticks, suggesting that FLEs-Hd presumably is a crucial symbiont of the host without specific tissue tropism. To further explore the function of the symbiont, the population dynamics of FLEs-Hd at each developmental stage of ticks and in tissues at different reproductive statuses were determined by real-time quantitative polymerase chain reaction (real-time qPCR). Results showed that the high density and regular population dynamics of FLEs-Hd appeared in female ovaries, suggesting that the symbiont may provide necessary nutrients or regulators to ensure normal ovary development of ticks.


Assuntos
Francisella/classificação , Ixodidae/microbiologia , Animais , DNA Bacteriano/genética , DNA Ribossômico/genética , Feminino , Francisella/genética , Francisella/fisiologia , Genes Bacterianos , Ixodidae/crescimento & desenvolvimento , Ixodidae/fisiologia , Masculino , Microscopia Eletrônica de Transmissão , Filogenia , Simbiose
14.
Ticks Tick Borne Dis ; 7(1): 188-192, 2016 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-26565930

RESUMO

Previously, we reported that Coxiella-like, Rickettsia-like and Arsenophonus-like symbionts could simultaneously coexist in Dermacentor silvarum. In this study, we examined their burdens and population dynamics in a single host during the host life cycle using quantitative PCR. Our results showed that multiple symbionts exhibited different abundances and varying trends in the tick host. Coxiella-like and Rickettsia-like symbionts were found at high densities in large quantities that fluctuated with time. This may coincide with oogenesis and mating of the host. Our findings provide insight into symbiont-tick interactions that lay the foundation for future studies.


Assuntos
Bactérias/isolamento & purificação , Dermacentor/microbiologia , Simbiose/fisiologia , Animais , Bactérias/genética , DNA Bacteriano/genética
15.
Phytother Res ; 29(3): 357-65, 2015 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-25418925

RESUMO

Studies have shown chemopreventive and/or chemotherapeutic effects of several curcumin-based combinatorial treatments on colorectal cancer cells. However, their in vivo effects remain unclear. This study has demonstrated the therapeutic effect of curcumin and oxaliplatin, alone or in combination, on subcutaneously xenografted LoVo human colorectal cancer cells in immunodeficient (nu/nu) mice in vivo. Combinatorial administration of curcumin and oxaliplatin evidently inhibited the growth of colorectal cancer in nude mice, which was significantly more effective than either agent alone. Curcumin combined with oxaliplatin treatment induced apoptosis, accompanied by ultrastructural changes and cell cycle arrest in S and G2/M phases. Further mechanism analysis indicated that while the number of apoptotic tumor cells and the expression of Bax, caspase-3, and poly (ADP-ribose) polymerase (PARP) increased significantly, the expression of Bcl-2, survivin, HSP70, pro-caspase-3, and pro-PARP were dramatically suppressed in tumor cells after the treatment with combinatorial curcumin and oxaliplatin for 22 days. Taken together, the present study has demonstrated that administration of combined curcumin and oxaliplatin effectively suppressed colorectal carcinoma in vivo through inducing apoptosis and thus may provide an effective treatment for colorectal carcinoma.


Assuntos
Apoptose/efeitos dos fármacos , Neoplasias Colorretais/tratamento farmacológico , Curcumina/farmacologia , Compostos Organoplatínicos/farmacologia , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Pontos de Checagem do Ciclo Celular , Linhagem Celular Tumoral , Neoplasias Colorretais/patologia , Sinergismo Farmacológico , Quimioterapia Combinada , Humanos , Masculino , Camundongos , Camundongos Nus , Oxaliplatina , Ensaios Antitumorais Modelo de Xenoenxerto
16.
Infect Genet Evol ; 21: 308-14, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24316292

RESUMO

As an obligate hematophagous ectoparasite, the hard tick Haemaphysalis longicornis exhibits two reproductive strategies, bisexual reproduction, and obligate parthenogenesis, which have attracted a widespread attention. However, the speciation of parthenogenetic population remained ambiguous due to its similarity in morphology but the remarkable differences in cytogenetics as compared with those of the bisexual ones. In the present study, we explored several new lines of genetic evidence to resolve this controversial issue. The number of the chromosomes in two lineages was checked by classical methods and their total DNA levels were determined utilizing flowcytometry. In addition, the sequences of 12S rDNA, 16S rDNA, cytochrome c oxidase I and II (COI, COII) and internal transcribed spacer-2 (ITS-2) genes were used to assess their phylogenetic relationship. We observed that the chromosome ploidy of bisexual and parthenogenetic H. longicornis collected by our laboratory was diploid and triploid, respectively. Flowcytometry analysis indicated a ratio close to 2:3 in the DNA contents of bisexual to parthenogenetic H. longicornis. Although the chromosome ploidy is different, their gene sequences are extremely similar. Analogous to the intra-species genetic difference of other invertebrates, sequence differences of all loci examined are below 2%. Phylogenetic trees constructed from 12S rDNA, 16S rDNA, COI, and ITS-2 genes revealed that they were all in the same monophyletic clade instead of splitting independently into evolutional branches. Moreover, according to 4× Rule, the K/θ ratio of two reproductive populations calculated based on COI was much smaller than four, strongly supporting that they belong to the same species. Therefore, we conclude that the evolutionary process just disturbs the chromosome ploidy and the sexual determination of parthenogenetic population and that it would be better to consider parthenogenetic H. longicornis as a metapopulation rather than a cryptic species.


Assuntos
Cromossomos de Insetos , Ixodidae/classificação , Ixodidae/genética , Partenogênese , Animais , DNA/análise , Genes de Insetos , Especiação Genética , Cariótipo , Filogenia , Ploidias
17.
Appl Environ Microbiol ; 79(7): 2450-4, 2013 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-23354701

RESUMO

We report that multiple symbionts coexist in Dermacentor silvarum. Based on 16S rRNA gene sequence analyses, we prove that Coxiella-like and Arsenophonus-like symbionts, with 95.6% and 96.7% sequence similarity to symbionts in the closest taxon, respectively, are novel. Moreover, we also provide evidence that the Coxiella-like symbiont appears to be the primary symbiont.


Assuntos
Coxiella/isolamento & purificação , Dermacentor/microbiologia , Enterobacteriaceae/isolamento & purificação , Rickettsia/isolamento & purificação , Animais , Análise por Conglomerados , Coxiella/classificação , Coxiella/genética , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Enterobacteriaceae/classificação , Enterobacteriaceae/genética , Dados de Sequência Molecular , Filogenia , RNA Ribossômico 16S/genética , Rickettsia/classificação , Rickettsia/genética , Análise de Sequência de DNA , Simbiose
18.
Parasit Vectors ; 6(1): 310, 2013 Oct 28.
Artigo em Inglês | MEDLINE | ID: mdl-24499619

RESUMO

BACKGROUND: Close relationships between ticks and microbial communities are important for tick fitness and pathogen colonization and transmission. Haemaphysalis longicornis, distributed widely in China, can carry and transmit various pathogens and pose serious damages to public health and economics. However, little is known about the broader array of microbial communities and symbionts in H. longicornis under natural conditions. In the present study, we investigated the composition of bacterial communities associated with H. longicornis and evaluated the putative symbionts. METHODS: The eubacterial 16S rRNA gene clone libraries of H. longicornis were constructed and analyzed by restriction fragment length polymorphism (RFLP) and DNA sequencing. In addition, diagnostic PCR was performed to assess the prevalence, vertical transmission and infection sites of the symbionts in H. longicornis. RESULTS: Vertically-transmitted symbionts, potential pathogens and allochthonous nonpathogenic bacteria were identified from the field-collected H. longicornis. Three types of symbionts (Coxiella-like, Arsenophonus-like and Rickettsia-like symbionts) were identified in a single host simultaneously. A series of analyses revealed the vertical transmission, prevalence, and infection sites of these symbionts. However, only Coxiella-like bacteria were transmitted stably in the laboratory-reared ticks. In addition, we identified a novel Coxiella-like agent with 95.31% sequence similarity to the taxon described previously. CONCLUSIONS: The present study demonstrated that natural H. longicornis harboured a diverse array of microbial communities. Three types of symbionts were identified in a single host simultaneously. Moreover, high prevalence, vertical transmission and the infection sites supported an obligate symbiotic association between Coxiella symbiont and its host. The role of Coxiella symbiont in the host fitness and the interaction among microbial communities remained to be elucidated. Our investigation of microbial communities in the ticks revealed the complexity of ecological interactions between host and microbe and provided insight for the biological control of ticks.


Assuntos
Bactérias/classificação , Bactérias/genética , Biota , Coxiella/fisiologia , Ixodidae/microbiologia , Simbiose , Animais , China , Análise por Conglomerados , DNA Bacteriano/química , DNA Bacteriano/genética , DNA Ribossômico/química , DNA Ribossômico/genética , Feminino , Masculino , Dados de Sequência Molecular , Filogenia , Polimorfismo de Fragmento de Restrição , RNA Ribossômico 16S/genética , Análise de Sequência de DNA
19.
Peptides ; 35(2): 285-90, 2012 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-22450466

RESUMO

Long time geographical isolation of Hainan Island from the China continent has resulted in appearance of many novel frog species. As one of them, Hainan odorous frog, Odorrana hainanensis possesses some special antimicrobial peptides distinct from those found in other Odorrana. In this study, three antimicrobial peptides have been purified and characterized from the skin secretion of O. hainanensis. With the similarity to the temporin family, two peptides are characterized by amidated C-terminals, so they are named as temporin-HN1 (AILTTLANWARKFL-NH(2)) and temporin-HN2 (NILNTIINLAKKIL-NH(2)). The third antimicrobial peptide belongs to the brevinin-1 family which is widely distributed in Eurasian ranids, and thus, it is named as brevinin-1HN1 (FLPLIASLAANFVPKIFCKITKKC). Furthermore, after sequencing 68 clones, eight cDNAs encoding antimicrobial peptide precursors were cloned from the skin-derived cDNA library of O. hainanensis. These eight cDNAs can encode seven mature antimicrobial peptides including the above three, as well as brevinin-1V, brevinin-2HS2, odorranain-A6, and odorranain-B1. Twelve different species of microorganisms were chosen, including Gram-positive, Gram-negative and fungi, to test the antimicrobial activities of temporin-HN1, temporin-HN2, brevinin-1HN1, brevinin-1V, and brevinin-2HS2. The result shows that, in addition to their activities against Gram-positive bacteria, temporin-HN1 and temporin-HN2 also possess activities against some Gram-negative bacteria and fungi. However, the two antimicrobial peptides, brevinin-1HN1 and brevinin-1V of the brevinin-1 family have stronger antimicrobial activities than temporin-HN1 and temporin-HN2 of the temporin family. Brevinin-1HN1 possesses activity against Staphylococcus aureus (ATCC25923), Rhodococcus rhodochrous X15, and Slime mould 090223 at the concentration of 1.2 µM.


Assuntos
Proteínas de Anfíbios/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Fungos/efeitos dos fármacos , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Ranidae/metabolismo , Sequência de Aminoácidos , Proteínas de Anfíbios/química , Proteínas de Anfíbios/isolamento & purificação , Animais , Anti-Infecciosos/química , Anti-Infecciosos/isolamento & purificação , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Feminino , Masculino , Testes de Sensibilidade Microbiana , Estrutura Secundária de Proteína , Proteínas/isolamento & purificação , Proteínas/farmacologia , Pele/metabolismo
20.
Int J Syst Evol Microbiol ; 56(Pt 10): 2405-2408, 2006 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-17012570

RESUMO

Two novel Pediococcus strains, Z-9(T) and Z-17, were isolated from a distilled-spirit-fermenting cellar in Hebei Province, China. The cells were Gram-positive, non-spore-forming, non-motile cocci and occurred in pairs or tetrads. The strains were facultatively anaerobic and produced only lactic acid [d(-) and l(+) isomers in the ratio 50 : 50] from glucose fermentation. Catalase activity was not present. Both strains were able to grow in 6.5 % ethanol and at pH 3.5, but not in 4 % NaCl. The mean genomic G+C content of the two strains was 39.5+/-0.5 mol% (39 mol% for the type strain, Z-9(T)). The levels of 16S rRNA gene sequence similarity between the two novel strains and related species of the genus Pediococcus ranged from 98.3 to 98.7 %. The levels of DNA-DNA relatedness between strain Z-9(T) and the phylogenetically closely related pediococci Pediococcus damnosus LMG 11484(T), Pediococcus inopinatus LMG 11409(T), Pediococcus parvulus LMG 11486(T) and Pediococcus cellicola LMG 22956(T) were 14.6, 33, 28.7 and 16.8 %, respectively. On the basis of phenotypic, genotypic and phylogenetic analyses, a novel species, Pediococcus ethanolidurans sp. nov., is proposed, with strain Z-9(T) (=AS 1.3889(T)=LMG 23354(T)) as the type strain.


Assuntos
Bebidas Alcoólicas/microbiologia , Pediococcus/classificação , Pediococcus/isolamento & purificação , Composição de Bases , China , DNA Bacteriano/análise , DNA Ribossômico/análise , Etanol/metabolismo , Fermentação , Genes de RNAr , Genótipo , Ácido Láctico/metabolismo , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , Pediococcus/genética , Pediococcus/fisiologia , Fenótipo , Filogenia , RNA Ribossômico 16S , Análise de Sequência de DNA
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA