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1.
J Cell Biochem ; 115(1): 189-98, 2014 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-24038094

RESUMO

Dendritic cells (DCs) are professional antigen-presenting cells (APCs) that play a critical role to activate immune response. They may be targeted for immunomodulation by microbes, including probiotics. In this study, chicken bone marrow dendrite cells (chi-BMDCs) were stimulated with lipopolysachride (LPS), Saccharomyces boulardii (Sb), Bacillus subtilis B10 (Bs), co-culture of Sb + Bs and phosphate buffer saline (PBS) as a control group (Ctr) at 3, 6, and 12 h intervals. Results revealed that treatment groups modulated the phenotype and biological functions of chi-BMDCs. Scan electron microscopy showed attachment of probiotics on the surface of chi-BMDCs. Additionally transmission electron microscopy (TEM) revealed efficiently engulfing and degradation of probiotics. Gene expression levels of MHC-II, CD40, CD80 and CD86 up-regulated in stimulated groups. Furthermore, toll-like receptors TLR1, TLR2, TLR4, and chicken specific TLR15 expressions were improved and downstream associated factors MyD88, TRAF6, TAB1, and NFκ-B mRNA levels increased in all treatment groups as compared to control. Surprisingly, NFκ-B response was noted significant higher in LPS treatment among all groups. Moreover, IL-1ß, IL-17, IL-4, TGF-ß, and IL-10 production levels were found higher, and lower concentration of INF-γ and IL-8 were observed in Sb, Bs, and Sb + Bs treatment groups. In contrast, LPS groups showed prominent increase in IL-12, INF-γ, and IL-8 concentration levels as compared to control group. Altogether, these results emphasize a potentially important role of Saccharomyces boulardii and Bacillus subtilis B10 in modulating immunological functions of chi-BMDCs by targeting specific toll like receptors (TLRs) and associated factors. The role of probiotics on chi-BMDCs functionality in a non-mammalian species have been presented for the first time.


Assuntos
Bacillus subtilis , Células da Medula Óssea/imunologia , Células Dendríticas/imunologia , Células Dendríticas/microbiologia , Probióticos/farmacologia , Saccharomyces , Receptores Toll-Like/metabolismo , Animais , Células da Medula Óssea/citologia , Células da Medula Óssea/microbiologia , Células Cultivadas , Quimiocinas/metabolismo , Galinhas , Citocinas/metabolismo , Células Dendríticas/efeitos dos fármacos , Regulação da Expressão Gênica , Lipopolissacarídeos/farmacologia , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , Transdução de Sinais
2.
Arch Microbiol ; 195(5): 349-56, 2013 May.
Artigo em Inglês | MEDLINE | ID: mdl-23455449

RESUMO

Depending on the microenvironment, macrophages can acquire distinct functional phenotypes, referred to as classically activated M1 and M2. M1 macrophages are considered potent effector cells that kill intracellular pathogens, and M2 macrophages promote the resolution of wound healing. In this study, we are interested to know whether probiotic Bacillus amyloliquefaciens (Ba) can induce macrophages polarization. Real-time fluorescence PCR analysis demonstrated that the expression of IL-1ß, iNOS, TNF-α and IL-6 genes for M1 macrophages was significantly increased at 1.5 h after probiotic Ba treatment compared to the probiotic Ba-free treatment (P < 0.01), whereas the expression of M2 macrophage marker genes (Arg1, Fizz1, MR, Ym1) was decreased (P < 0.05). Furthermore, the phagocytic activity was dramatically increased in the Ba-treated BMDMs using a FITC-dextran endocytosis assay. Together, these findings indicated that probiotic Ba facilitated polarization of M1 macrophages and enhanced its phagocytic capacity. The results expanded our knowledge about probiotic function-involved macrophage polarization.


Assuntos
Bacillus , Ativação de Macrófagos , Macrófagos/imunologia , Probióticos/administração & dosagem , Transcriptoma , Animais , Bacillus/classificação , Bacillus/metabolismo , Macrófagos/citologia , Macrófagos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Óxido Nítrico/metabolismo
3.
Pharm Biol ; 49(3): 256-61, 2011 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-20979538

RESUMO

CONTEXT: Scutellaria baicalensis Georgi (Labiatae) (SbG), one of the fifty fundamental herbs of Chinese herbology, has been reported to have anti-asthmatic, antifungal, antioxidative, and anti-inflammatory activities. OBJECTIVE: This study was designed to determine the protective effects of the extract of SbG against the acrolein-induced oxidative stress in cultured human umbilical vein endothelial cells (HUVEC). MATERIALS AND METHODS: The MTT reduction assay was employed to determine cell viability. The total cellular glutathione (GSH) level was detected using a colorimetric GSH assay kit. Cellular GSH production was conducted by detecting the mRNA expression levels of γ-glutamylcysteine ligase catalytic subunit and modifier subunit. RESULTS: Concentration-dependent cytotoxic effects of acrolein were observed while SbG could effectively protect the acrolein-induced oxidative damage. The protective mechanism was investigated, showing that the increased GSH content in the SbG-incubated HUVE cells was associated with the protective effects of SbG-treated cells. Further RT-PCR data confirmed the elevated mRNA expressions of GSH synthesis enzymes. DISCUSSION AND CONCLUSION: The current study strongly indicated that SbG could be a potential antioxidant against oxidative stress in treating cardiovascular diseases.


Assuntos
Acroleína/antagonistas & inibidores , Acroleína/toxicidade , Endotélio Vascular/metabolismo , Estresse Oxidativo/fisiologia , Extratos Vegetais/farmacologia , Veias Umbilicais/metabolismo , Sobrevivência Celular/efeitos dos fármacos , Sobrevivência Celular/fisiologia , Células Cultivadas , Endotélio Vascular/citologia , Endotélio Vascular/efeitos dos fármacos , Humanos , Estresse Oxidativo/efeitos dos fármacos , Substâncias Protetoras/farmacologia , Scutellaria baicalensis , Veias Umbilicais/citologia , Veias Umbilicais/efeitos dos fármacos
4.
Front Vet Sci ; 8: 679368, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34150896

RESUMO

The aim of this study was to evaluate the dietary effects of Bacillus amyloliquefaciens SC06 (SC06) instead of antibiotics on the growth performance, intestinal health, and intestinal microbiota of broilers. A total of 360 30-day-old Lingnan yellow broilers were randomly allocated into two groups with six replicates per group (30 birds per replicate). The broilers were fed either a non-supplemented diet or a diet supplemented with 108 colony-forming units lyophilized SC06 per kilogram feed for 30 days. Results showed that SC06 supplementation had no effect on the growth performance compared with that of the control group. SC06 treatment significantly (P <0.05) increased the total antioxidant capacity (T-AOC), total superoxide dismutase (T-SOD) activity in the liver, and the activities of trypsin, α-amylase (AMS), and Na+K+-ATPase in the ileum, whereas it decreased (P < 0.05) lipase, gamma glutamyl transpeptidase (γ-GT), and maltase activities in the ileum. Meanwhile, SC06 treatment also improved the immune function indicated by the significantly (P < 0.05) increased anti-inflammatory cytokine [interleukin (IL)-10] level and the decreased (P < 0.05) pro-inflammatory cytokine [IL-6 and tumor necrosis factor (TNF)-α] levels in the ileum. Furthermore, we also found that SC06 enhanced the intestinal epithelial intercellular integrity (tight junction and adhesion belt) in the ileum. Microbial analysis showed that SC06 mainly increased the alpha diversity indices in the jejunum, ileum, and cecum. SC06 treatment also significantly (P < 0.05) increased the abundances of Bacteroidetes, Bacteroidales, Bacteroides, Fusobacteria, Clostridiaceae, and Veillonellaceae in the cecum and simultaneously decreased the abundances of Planococcaceae in the duodenum, Microbacteriaceae in the jejunum, and Lachnospiraceae, [Ruminococcus] and Ruminococcus in cecum. In conclusion, these results suggested that B. amyloliquefaciens instead of antibiotics showed a potential beneficial effect on the intestinal health of broilers.

5.
Am J Cancer Res ; 11(5): 1895-1912, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34094660

RESUMO

As an important trace element, iron plays an essential role in many biology processes like cell proliferation, metabolism, and mitochondrial function. However, the disruption of iron homeostasis tends to cells death and human diseases due to it servers as mediator to promote the production of reactive oxygen species (ROS). In this review, first we introduced the mechanism of complex iron-mediated ROS involved in apoptosis, necroptosis, ferroptosis and pyroptosis. Next, we discussed the controversial role of excess iron and iron deficiency in tumor. Finally, we discussed the anti-cancer effects of iron on both sides, and novel iron-related strategies. This review outlined the mechanisms and regulation of iron homeostasis and iron-mediated ROS in tumors, and discussed the iron-related treatments.

6.
Fish Shellfish Immunol ; 28(1): 49-55, 2010 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-19800009

RESUMO

The protective efficacy of oral administration of VP28 using Bacillus subtilis as vehicles (rVP28-bs) in shrimp, Fenneropenaeus chinensis, upon challenge with white spot syndrome virus (WSSV) was investigated. The calculated relative percent survival (RPS) value of rVP28-bs fed shrimp was 83.3% when challenged on the 14th day post-administration, which is significantly higher (p < 0.001) than that of the group administered recombinant Escherichia coli over-expressing rVP28 (rVP28-e21). After immunization, activities of phenoloxidase (PO), superoxide dismutase (SOD) and inducible nitric oxide synthase (iNOS) in hemolymph were analyzed. It was found that the supplementation of rVP28-bs into shrimp food pellets resulted in the most pronounced increase of iNOS activity (p < 0.001), but had the least influence on activities of PO and SOD. Besides, in the shrimp orally administered with rVP28-bs, the caspase-3 activity was one-fifth that of the control, though the signs of apoptosis (chromatin margination, nuclear fragmentation and apoptotic bodies) could not be observed by transmission electron microscope (TEM). These results suggest that by oral delivery of rVP28-bs, shrimp showed significant resistance to WSSV and an effect on the innate immune system of shrimp. The remarkably enhanced level of iNOS after rVP28-bs administration might be responsible for antiviral defense in shrimp.


Assuntos
Penaeidae/imunologia , Vírus da Síndrome da Mancha Branca 1/imunologia , Animais , Apoptose/imunologia , Bacillus subtilis/virologia , Caspase 3/metabolismo , Imunidade Inata/imunologia , Monofenol Mono-Oxigenase/metabolismo , Óxido Nítrico Sintase/metabolismo , Penaeidae/enzimologia , Penaeidae/virologia , Superóxido Dismutase/metabolismo
7.
Biotechnol Lett ; 32(7): 963-7, 2010 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-20229062

RESUMO

To elucidate the effects of C-terminal domains of LicMB (mature lichenase from Clostridium thermocellum) and terminal residues of LicMB-CD (catalytic domain of LicMB) on the properties of lichenase, a series of truncated genes were constructed and expressed in E. coli. The Thr-Pro box had a positive effect while the dockerin domain had a negative impact on the properties of LicMB. The N-terminal 10-25th and C-terminal 1-9th residues of LicMB-CD were necessary to retain high thermostability while the N-terminal 1-7th and C-terminal 1-3rd residues were not necessary to maintain enzymatic activity.


Assuntos
Proteínas de Bactérias/química , Proteínas de Bactérias/metabolismo , Clostridium thermocellum/enzimologia , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/metabolismo , Proteínas de Bactérias/genética , Domínio Catalítico , Estabilidade Enzimática , Escherichia coli/genética , Expressão Gênica , Glicosídeo Hidrolases/genética , Proteínas Mutantes/química , Proteínas Mutantes/genética , Proteínas Mutantes/metabolismo , Estabilidade Proteica , Deleção de Sequência , Temperatura
8.
Biotechnol Lett ; 31(7): 991-7, 2009 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-19277476

RESUMO

K88 (F4) fimbrial adhesin, FaeG, was expressed extracellularly in Lactococcus lactis using a nisin-controlled gene expression system. The antibody response and protective efficacy of the recombinant bacteria (L. lactis [spNZ8048-faeG]) against live enterotoxigenic E. coli (ETEC) C(83549) challenge were evaluated in ICR mice. Mice vaccinated with L. lactis [spNZ8048-faeG] had a significantly increased antigen-specific IgG level in the serum and decreased mortality rate (P < 0.05) compared with the control. This indicates that oral immunization of L. lactis [spNZ8048-faeG] can induce an immune-response protection upon challenge with live ETEC in ICR mice.


Assuntos
Adesinas de Escherichia coli/biossíntese , Escherichia coli Enterotoxigênica/imunologia , Infecções por Escherichia coli/prevenção & controle , Vacinas contra Escherichia coli/imunologia , Lactococcus lactis/genética , Adesinas de Escherichia coli/genética , Adesinas de Escherichia coli/imunologia , Administração Oral , Animais , Anticorpos Antibacterianos/sangue , DNA Bacteriano/química , DNA Bacteriano/genética , Escherichia coli Enterotoxigênica/genética , Vacinas contra Escherichia coli/administração & dosagem , Vacinas contra Escherichia coli/genética , Imunoglobulina G/sangue , Lactococcus lactis/imunologia , Lactococcus lactis/metabolismo , Camundongos , Camundongos Endogâmicos ICR , Dados de Sequência Molecular , Análise de Sequência de DNA , Análise de Sobrevida
9.
J Zhejiang Univ Sci B ; 20(2): 180-192, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-30666850

RESUMO

To understand the effects of Lactobacillus rhamnosus GG (ATCC 53103) on intestinal barrier function in pre-weaning piglets under normal conditions, twenty-four newborn littermate piglets were randomly divided into two groups. Piglets in the control group were orally administered with 2 mL 0.1 g/mL sterilized skim milk while the treatment group was administered the same volume of sterilized skim milk with the addition of viable L. rhamnosus at the 1st, 3rd, and 5th days after birth. The feeding trial was conducted for 25 d. Results showed that piglets in the L. rhamnosus group exhibited increased weaning weight and average daily weight gain, whereas diarrhea incidence was decreased. The bacterial abundance and composition of cecal contents, especially Firmicutes, Bacteroidetes, and Fusobacteria, were altered by probiotic treatment. In addition, L. rhamnosus increased the jejunal permeability and promoted the immunologic barrier through regulating antimicrobial peptides, cytokines, and chemokines via Toll-like receptors. Our findings indicate that oral administration of L. rhamnosus GG to newborn piglets is beneficial for intestinal health of pre-weaning piglets by improving the biological, physical, and immunologic barriers of intestinal mucosa.


Assuntos
Mucosa Intestinal/imunologia , Lacticaseibacillus rhamnosus , Probióticos/administração & dosagem , Administração Oral , Animais , Animais Recém-Nascidos , Citocinas/genética , Feminino , Microbioma Gastrointestinal , Imunidade Inata , Masculino , Transdução de Sinais , Suínos , Desmame
10.
J Zhejiang Univ Sci B ; 19(10): 785-795, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30269446

RESUMO

OBJECTIVE: Salmonella enterica remains a major cause of food-borne disease in humans, and Salmonella Typhimurium (ST) contamination of poultry products is a worldwide problem. Since macrophages play an essential role in controlling Salmonella infection, the aim of this study was to evaluate the effect of glycyrrhizic acid (GA) on immune function of chicken HD11 macrophages. METHODS: Chicken HD11 macrophages were treated with GA (0, 12.5, 25, 50, 100, 200, 400, or 800 µg/ml) and lipopolysaccharide (LPS, 500 ng/ml) for 3, 6, 12, 24, or 48 h. Evaluated responses included phagocytosis, bacteria-killing, gene expression of cell surface molecules (cluster of differentiation 40 (CD40), CD80, CD83, and CD197) and antimicrobial effectors (inducible nitric oxide synthase (iNOS), NADPH oxidase-1 (NOX-1), interferon-γ (IFN-γ), LPS-induced tumor necrosis factor (TNF)-α factor (LITAF), interleukin-6 (IL-6), and IL-10), and production of nitric oxide (NO) and hydrogen peroxide (H2O2). RESULTS: GA increased the internalization of both fluorescein isothiocyanate (FITC)-dextran and ST by HD11 cells and markedly decreased the intracellular survival of ST. We found that the messenger RNA (mRNA) expression of cell surface molecules (CD40, CD80, CD83, and CD197) and cytokines (IFN-γ, IL-6, and IL-10) of HD11 cells was up-regulated following GA exposure. The expression of iNOS and NOX-1 was induced by GA and thereby the productions of NO and H2O2 in HD11 cells were enhanced. Notably, it was verified that nuclear factor-κB (NF-κB) and c-Jun N-terminal kinase (JNK) pathways were responsible for GA-induced synthesis of NO and IFN-γ gene expression. CONCLUSIONS: Taken together, these results suggested that GA exhibits a potent immune regulatory effect to activate chicken macrophages and enhances Salmonella-killing capacity.


Assuntos
Ácido Glicirrízico/farmacologia , Ativação de Macrófagos/efeitos dos fármacos , Salmonella/efeitos dos fármacos , Animais , Células Cultivadas , Galinhas , NF-kappa B/fisiologia , Fagocitose/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos
11.
J Zhejiang Univ Sci B ; 8(9): 686-92, 2007 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-17726751

RESUMO

The objectives of this study were to assess the potential of two photosynthetic bacteria (PSB), Rhodopseudomonas palustris HZ0301 and Rhodobacter sphaeroides HZ0302, as probiotics in aquaculture. The viability of HZ0301 and HZ0302 in simulated gastric transit conditions (pH 2.0, pH 3.0 and pH 4.0 gastric juices) and in simulated small intestinal transit conditions (pH 8.0, with or without 0.3% bile salts) was tested. The effects of HZ0301 and HZ0302 on the viability and permeability of intestinal epithelial cell in primary culture of tilapias, Oreochromis nilotica, were also detected. All the treatments were determined with three replicates. The simulated gastric transit tolerance of HZ0301 and HZ0302 strains was pH-dependent and correspondingly showed lower viability at pH 2.0 after 180 min compared with pH 3.0 and pH 4.0. Both HZ0301 and HZ0302 were tolerant to simulated small intestine transit with or without bile salts in our research. Moreover, there was no significant difference (P>0.05) among three treatments including the control and the groups treated with HZ0301 or HZ0302 both in intestinal epithelial cell viability and membrane permeability, showing no cell damage. In summary, this study demonstrated that HZ0301 and HZ0302 had high capacity of upper gastrointestinal transit tolerance and were relatively safe for intestinal epithelial cells of tilapias.


Assuntos
Trato Gastrointestinal/microbiologia , Viabilidade Microbiana , Rhodobacter sphaeroides/isolamento & purificação , Rhodobacter sphaeroides/fisiologia , Rodopseudomonas/isolamento & purificação , Rodopseudomonas/fisiologia , Tilápia/microbiologia , Animais , Processos Fototróficos , Especificidade da Espécie
12.
Mol Med Rep ; 16(4): 4151-4158, 2017 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-28731127

RESUMO

Pidotimod is a synthetic dipeptide with biological and immuno­modulatory properties. It has been widely used for treatment and prevention of recurrent respiratory infections. However, its impact on the regulation of allergic pulmonary inflammation is still not clear. In the current study, an ovalbumin (OVA)­induced allergic asthma model was used to investigate the immune­modulating effects of pidotimod on airway eosinophilia, mucus metaplasia and inflammatory factor expression compared with dexamethasone (positive control). The authors determined that treatment with pidotimod exacerbated pulmonary inflammation as demonstrated by significantly increased eosinophil infiltration, dramatically elevated immunoglobulin E production, and enhanced T helper 2 response. Moreover, treatment failed to attenuate mucus production in lung tissue, and did not reduce OVA­induced high levels of FIZZ1 and Arg1 expression in asthmatic mice. In contrast, administration of dexamethasone was efficient in alleviating allergic airway inflammation in OVA­induced asthmatic mice. These data indicated that pidotimod as an immunotherapeutic agent should be used cautiously and the effectiveness for controlling allergic asthma needs further evaluation and research.


Assuntos
Asma/complicações , Asma/tratamento farmacológico , Hipersensibilidade/tratamento farmacológico , Ácido Pirrolidonocarboxílico/análogos & derivados , Infecções Respiratórias/complicações , Infecções Respiratórias/tratamento farmacológico , Tiazolidinas/uso terapêutico , Animais , Arginase/metabolismo , Asma/sangue , Asma/imunologia , Líquido da Lavagem Broncoalveolar , Diferenciação Celular/efeitos dos fármacos , Modelos Animais de Doenças , Regulação para Baixo/efeitos dos fármacos , Eosinófilos/efeitos dos fármacos , Eosinófilos/patologia , Feminino , Hipersensibilidade/sangue , Hipersensibilidade/complicações , Hipersensibilidade/patologia , Imunoglobulina E/sangue , Imunoglobulina E/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Pulmão/patologia , Metaplasia , Camundongos Endogâmicos C57BL , Muco/efeitos dos fármacos , Muco/metabolismo , Ovalbumina , Ácido Pirrolidonocarboxílico/farmacologia , Ácido Pirrolidonocarboxílico/uso terapêutico , Infecções Respiratórias/sangue , Infecções Respiratórias/patologia , Células Th2/efeitos dos fármacos , Células Th2/imunologia , Tiazolidinas/farmacologia
13.
Immunol Lett ; 105(1): 68-76, 2006 May 15.
Artigo em Inglês | MEDLINE | ID: mdl-16600384

RESUMO

The effectiveness of oral, mock-, and immersion vaccination was investigated against white spot syndrome virus (WSSV) in crayfish. The most exposed WSSV envelope proteins VP19 and VP28 were used in different compositions and with different modes of applications. In experiment 1 crayfish were fed recombinant protein coated food pellets for 25 days, in experiment 2 the purified proteins were directly injected to them followed by one booster dose on 5th day and in experiment 3 the crayfish were left immersed in vaccines for 7 h. Experimental crayfish were challenged on 3rd and 21st days after last vaccination. The overall result showed that VP28 group has lowest cumulative mortality percentage accounting 39.6% at 3rd day and 39.83% at 21st day when injected and it was 43.2% and 49% when fed orally and 46.3% and 46.5% when immersed at 3rd and 21st days, respectively (p<0.05). In VP19 and VP28 (50:50) mixture, mock vaccination showed better performance (36.5%) over immersion (53%) and oral vaccination (53.2%) when challenged on 3rd day and mock vaccination (36.50%) followed by oral (51%) and immersion vaccination (56.5%) on 21st day as well. The VP19 recombinant mock vaccination group performed better (52.91% of 3rd day and 56.46% of 21st day) than oral (76% of 3rd day and 82% of 21st day) and immersion (83% of 3rd day and 86.3% of 21st day) vaccine groups. All the experimental groups except VP19 were significantly different (p<0.05) from the control groups. A positive cumulative effect was observed when VP28 was mixed with VP19 in equal proportion in all the experimental trials, which shows the effectiveness of VP19 as a vaccine component too. In the present trial on the basis of cumulative mortality percentage it is found that mock-vaccination group is more effective than the oral vaccination and immersion vaccination. It also suggests that specific memory exists in crayfish and the effects of VP28 are significant. The effect of VP19 along with VP28 has also shown significant effect against WSSV.


Assuntos
Astacoidea/imunologia , Astacoidea/virologia , Vacinas Virais/farmacologia , Vírus da Síndrome da Mancha Branca 1/imunologia , Animais , Sequência de Bases , Clonagem Molecular , DNA Viral/genética , Genes Virais , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética , Vacinas Sintéticas/farmacologia , Vacinas Virais/administração & dosagem , Vacinas Virais/genética , Viroses/imunologia , Viroses/prevenção & controle , Viroses/virologia , Vírus da Síndrome da Mancha Branca 1/genética , Vírus da Síndrome da Mancha Branca 1/patogenicidade
14.
Biotechnol Adv ; 24(3): 285-95, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16380225

RESUMO

Lactic acid bacteria are widely used in industrial fermentation. The potential use of these bacteria as homologous and heterologous protein expression hosts has been investigated extensively. The NIsin-Controlled gene Expression system (the NICE system) is an efficient and promising gene expression system based on the autoregulation mechanism of nisin biosynthesis in the Lactococcus lactis. In the NICE system, the membrane-located histidine kinase NisK senses the inducing signal nisin and autophosphorylates, then transfers phosphorous group to intracellular response regulator protein NisR which activates nisA promoter to express the downstream gene(s). The NICE system allows regulated overproduction of a variety of interest proteins by several Gram-positive bacteria, especially L. lactis. The essential elements for system construction, its application for expression of some biotechnologically important proteins and further improvements of this system are discussed.


Assuntos
Regulação Bacteriana da Expressão Gênica , Técnicas Genéticas , Nisina/genética , Expressão Gênica , Genes Bacterianos/genética , Vetores Genéticos/genética
15.
Peptides ; 27(9): 2350-9, 2006 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-16675061

RESUMO

Apidaecins (apidaecin-type peptides) refer to a series of small, proline-rich (Pro-rich), 18- to 20-residue peptides produced by insects. They are the largest group of Pro-rich antimicrobial peptides (AMPs) known to date. Structurally, apidaecins consist of two regions, the conserved (constant) region, responsible for the general antibacterial capacity, and the variable region, responsible for the antibacterial spectrum. The small, gene-encoded and unmodified apidaecins are predominantly active against many gram-negative bacteria by special antibacterial mechanisms. The mechanism of action by which apidaecins kill bacteria involves an initial non-specific binding of the peptides to an outer membrane (OM) component. This binding is followed by invasion of the periplasmic space, and by a specific and essentially irreversible combination with a receptor/docking molecule that may be a component of a permease-type transporter system on inner membrane (IM). In the final step, the peptide is translocated into the interior of the cell where it meets its ultimate target. Evidence that apidaecins are non-toxic for human and animal cells is a prerequisite for using them as novel antibiotic drugs. This review presents the biodiversity, structure-function relationships, and mechanism of action of apidaecins.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Sequência de Aminoácidos , Animais , Antibacterianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/metabolismo , Humanos , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Modelos Biológicos , Dados de Sequência Molecular , Relação Estrutura-Atividade
16.
FEMS Microbiol Lett ; 261(2): 224-30, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16907724

RESUMO

A chimeric gene, Glu-Xyl, encoding Bacillus amyloliquefaciens glucanase (Glu, 24.4 kDa) and Bacillus subtilis xylanase (Xyl, 21.2 kDa), was constructed via end-to-end fusion and expressed successfully in Escherichia coli. The purified fusion protein (46.1 kDa) exhibited both glucanase and xylanase activities. Compared with parental enzymes, the Glu moiety was characterized by kinetic parameters of decreased K(m) (0.66-fold) and increased K(cat) (2.75-fold), whereas the Xyl moiety had an increased K(m) (1.37-fold) and decreased K(cat) (0.79-fold). These indicate a 3.15-fold net increase and a 31% decrease in catalytic efficiency (K(cat)/K(m)) of the Glu and Xyl moieties. Activities and stabilities of both moieties at 40-90 degrees C or pH 3.0-10.0 were compared with those of the parental enzymes. Despite some variations, common optima were 40 degrees C and pH 9.0 for the Glu moiety and parent, and 50-60 degrees C and pH 9.0 for the Xyl counterparts. Thus, the fusion enzyme Glu-Xyl was bifunctional, with greatly enhanced glucanase activity associated with a decrease in xylanase activity.


Assuntos
Bacillus subtilis/enzimologia , Bacillus/enzimologia , Glicosídeo Hidrolases/genética , Glicosídeo Hidrolases/metabolismo , Fusão Gênica Artificial , Bacillus/genética , Bacillus subtilis/genética , Sequência de Bases , Cromatografia , Clonagem Molecular/métodos , Escherichia coli/genética , Glicosídeo Hidrolases/química , Glicosídeo Hidrolases/isolamento & purificação , Cinética , Dados de Sequência Molecular , Proteínas Recombinantes de Fusão/química , Xilanos/metabolismo , beta-Glucanas/metabolismo
17.
J Trace Elem Med Biol ; 20(2): 83-7, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16785047

RESUMO

Thirty-two barrows (Duroc x Landrace x Yorkshire) were randomly divided into four groups, each of which included eight pigs. The groups received the same basal diet supplemented with 0, 100, 250 and 400mg/kg fluoride, respectively. The malondialdehyde (MDA) and glutathione (GSH) levels, antioxidant enzymes activities and zinc/copper superoxide dismutase (Cu/Zn SOD) mRNA content in the liver were determined to evaluate the fluoride hepatic intoxication. Results showed the increased lipid peroxides (LPO) level and the reduced GSH content, along with a concomitant decrease in the activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px). Moreover, the level of hepatic Cu/Zn SOD mRNA was also significantly reduced. We suggest the mechanism of fluoride injuring the liver as follows: fluoride causes a decrease in Cu/Zn SOD mRNA and the reduced activities of antioxidant enzymes, leads to the declined ability of scavenging free radicals with excessive production of LPO, which seriously damages the hepatic structure and function.


Assuntos
Antioxidantes/farmacologia , Fluoretos/farmacologia , Fígado/enzimologia , Superóxido Dismutase/metabolismo , Transcrição Gênica , Animais , Catalase/genética , Catalase/metabolismo , Regulação Enzimológica da Expressão Gênica , Glutationa/genética , Glutationa/metabolismo , Glutationa Peroxidase/genética , Glutationa Peroxidase/metabolismo , Peroxidação de Lipídeos , Masculino , Malondialdeído/metabolismo , Distribuição Aleatória , Superóxido Dismutase/genética , Suínos
18.
Dis Aquat Organ ; 71(2): 175-8, 2006 Jul 25.
Artigo em Inglês | MEDLINE | ID: mdl-16956066

RESUMO

The effect of hyperthermia on the development of white spot syndrome virus (WSSV) in the crayfish Procambarus clarkii was studied by competitive PCR. Crayfish were exposed to different temperatures (24 +/- 1 and 32 +/- 1 degrees C) after WSSV injection. No mortality was observed when crayfish were held at 32 +/- 1 degrees C, but mortality reached 100% when crayfish were transferred to 24 +/- 1 degrees C. Competitive PCR showed that viral levels at 32 +/- 1 degrees C remained at 10(5) copies mg(-1) tissue, while at 24 +/- 1 degrees C levels were significantly higher, rising from 10(4) to 10(10) copies mg(-1) tissue. These results suggest that hyperthermia reduces viral replication, but does not eliminate viral particles from WSSV-infected crayfish.


Assuntos
Astacoidea/virologia , Temperatura Alta , Replicação Viral/fisiologia , Vírus da Síndrome da Mancha Branca 1/fisiologia , Animais , Primers do DNA/química , Brânquias/virologia , Reação em Cadeia da Polimerase/métodos , Análise de Sobrevida , Fatores de Tempo
19.
J Zhejiang Univ Sci B ; 16(6): 487-95, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26055910

RESUMO

While a high-fat diet (HFD) is assumed to be related to fat-mediated oxidative stress decreasing antioxidant enzyme activity, probiotics are believed to have positive effects on the regulation of HFD-induced obesity as well as lipid metabolism, energy homeostasis, and anti-oxidation. Because Bacillus subtilis B10 has beneficial effects on the abnormal lipid metabolism and the oxidative stress in HFD-induced obese mice, ICR mice were randomly assigned into an HFD group and the HFD was supplemented with 0.1% (w/w) Bacillus subtilis B10 (HFD+B10 group). Thereafter, 30-d treatments were run, and then hepatic lipid level and antioxidant status were measured. The expression of genes related to lipid metabolism and oxidative stress in the liver was determined by reverse-transcription quantitative polymerase chain reaction (RT-qPCR). We found that HFD-induced obese mice treated with B10 showed a decrease in weight gain, serum glucose activity as well as hepatic triglyceride (TG), glutamic oxaloacetic transaminase (GOT), and glutamic pyruvic transaminase (GPT) activities. In addition, the gene expressions of antioxidant genes, glutathione reductase (GR), xanthine oxidase (XO), heat-shock protein 90 (Hsp90), and lipid synthesis gene 3ß-hydroxysteroid-∆24 reductase (DHCR24) in the HFD+B10 group were down-regulated, suggesting alleviation of oxidative stress, while the lipolysis gene 3-hydroxy-3-methylglutaryl-CoA synthase 2 (HMGCS2), energy metabolism gene peroxisome proliferator-activated receptor α (PPARα) and the gene encoding tumor-suppressor protein p53 were up-regulated. The regulatory and positive effect of dietary supplementation of probiotic B10 suggests that it has a beneficial effect on the homeostasis of the lipid metabolism and on alleviating oxidative stress in HFD-induced obese mice.


Assuntos
Bacillus subtilis/fisiologia , Metabolismo dos Lipídeos , Obesidade/metabolismo , Obesidade/microbiologia , Probióticos/administração & dosagem , Espécies Reativas de Oxigênio/metabolismo , Administração Oral , Animais , Gorduras na Dieta , Metabolismo Energético , Masculino , Camundongos , Camundongos Endogâmicos ICR , Obesidade/dietoterapia , Espécies Reativas de Oxigênio/sangue , Resultado do Tratamento
20.
World J Gastroenterol ; 10(6): 856-9, 2004 Mar 15.
Artigo em Inglês | MEDLINE | ID: mdl-15040032

RESUMO

AIM: To investigate effects of non-starch polysaccharides(NSP) enzymes on pancreatic and small intestinal digestive enzyme activities in piglet fed diets containing high amounts of barley. METHODS: Sixty crossbred piglets averaging 13.5 kg were randomly assigned to two treatment groups with three replications (pens) based on sex and mass. Each group was fed on the diet based on barley with or without added NSP enzymes (0.15%) for a 40-d period. At the end of the experiment the pigs were weighed. Three piglets of each group were chosen and slaughtered. Pancreas, digesta from the distal end of the duodenum and jejunal mucosa were collected for determination. Activities of the digestive enzymes trypsin, chymotrypsin, amylase and lipase were determined in the small intestinal sections as well as in homogenates of pancreatic tissue. Maltase, sucrase, lactase and gamma-glutamyl transpeptidase (gamma-GT) activities were analyzed in jejunal mucosa. RESULTS: Supplementation with NSP enzymes improved growth performance of piglets. It showed that NSP enzymes had no effect on digestive enzyme activities in pancreas, but decreased the activities of proteolytic enzyme, trypsin, amylase and lipase in duodenal contents by 57.56%, 76.08%, 69.03% and 40.22%(P<0.05) compared with control, and increased gamma-GT activities in jejunal mucosa by 118.75%(P<0.05). CONCLUSION: Supplementation with NSP enzymes in barley based diets could improve piglets' growth performance, decrease activities of proteolytic enzyme, trypsin, amylase and lipase in duodenal contents and increase gamma-GT activities in jejunal mucosa.


Assuntos
Animais Recém-Nascidos/metabolismo , Dieta , Enzimas/farmacologia , Hordeum , Intestino Delgado/metabolismo , Pâncreas/metabolismo , Polissacarídeos/metabolismo , Animais , Digestão/fisiologia , Enzimas/metabolismo , Suínos
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