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1.
Int J Med Mushrooms ; 19(9): 759-766, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29199551

RESUMO

People seek a greater quality of life and healthy aging that culminates in improved self-esteem and vitality in the performance of daily activities; this is generating a growing number of people enrolled in gyms in search of quick results. However, this training can result in physical and metabolic damage. During physical exercise, under conditions of oxidative stress, changes take place that lead to the onset of fatigue. The Agaricus brasiliensis mushroom is native to Brazil and has therapeutic potential, with widely studied antioxidant and immunomodulatory capabilities. However, little is known about its potential benefits regarding muscular strength. Therefore, this study evaluated the possible effects of supplementation with this mushroom with respect to strength performance before and after a resistance training session. A blinded randomized trial was performed with male volunteers (n = 5) randomly divided into 2 groups (placebo and treatment with A. brasiliensis). Perceptions of muscle soreness and performance were assessed before and after high-intensity resistance training sessions. The study was executed over a 24-day period. Promising results were found related to intrasession rapid strength, most likely a result of antioxidant action and redox balance. The bioactive compounds in A. brasiliensis revealed the potential to improve conditions of muscle fatigue without altering other parameters. Thus, this mushroom has become a target of great expectations in the fields of fitness and athletics.


Assuntos
Agaricus , Antioxidantes/uso terapêutico , Suplementos Nutricionais , Fatores Imunológicos/uso terapêutico , Fadiga Muscular/efeitos dos fármacos , Humanos , Masculino , Estresse Oxidativo/efeitos dos fármacos , Condicionamento Físico Humano , Qualidade de Vida
2.
Malar J ; 14: 311, 2015 Aug 11.
Artigo em Inglês | MEDLINE | ID: mdl-26260055

RESUMO

BACKGROUND: Cerebral malaria (CM) is debilitating and sometimes fatal. Disease severity has been associated with poor treatment access, therapeutic complexity and drug resistance and, thus, alternative therapies are increasingly necessary. In this study, the effect of the administration of Agaricus blazei, a mushroom of Brazilian origin in a model of CM caused by Plasmodium berghei, strain ANKA, was investigated in mice. METHODS: C57BL/6 mice were pre-treated with aqueous extract or fractions of A. blazei, or chloroquine, infected with P. berghei ANKA and then followed by daily administration of A. blazei or chloroquine. Parasitaemia, body weight, survival and clinical signs of the disease were evaluated periodically. The concentration of pro-and anti-inflammatory cytokines, histopathology and in vitro analyses were performed. RESULTS: Mice treated with A. blazei aqueous extract or fraction C, that shows antioxidant activity, displayed lower parasitaemia, increased survival, reduced weight loss and protection against the development of CM. The administration of A. blazei resulted in reduced levels of TNF, IL-1ß and IL-6 production when compared to untreated P. berghei-infected mice. Agaricus blazei (aqueous extract or fraction C) treated infected mice displayed reduction of brain lesions. Although chloroquine treatment reduced parasitaemia, there was increased production of proinflammatory cytokines and damage in the CNS not observed with A. blazei treatment. Moreover, the in vitro pretreatment of infected erythrocytes followed by in vivo infection resulted in lower parasitaemia, increased survival, and little evidence of clinical signs of disease. CONCLUSIONS: This study strongly suggests that the administration of A. blazei (aqueous extract or fraction C) was effective in improving the consequences of CM in mice and may provide novel therapeutic strategies.


Assuntos
Agaricus/química , Anti-Inflamatórios/farmacologia , Antimaláricos/farmacologia , Produtos Biológicos/farmacologia , Malária Cerebral/tratamento farmacológico , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/uso terapêutico , Antimaláricos/química , Antimaláricos/uso terapêutico , Produtos Biológicos/química , Produtos Biológicos/uso terapêutico , Encéfalo/efeitos dos fármacos , Encéfalo/patologia , Citocinas/sangue , Feminino , Malária Cerebral/fisiopatologia , Malária Cerebral/prevenção & controle , Camundongos , Camundongos Endogâmicos C57BL
3.
Biomed Res Int ; 2014: 108913, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-25530954

RESUMO

Lipolytic potential of Aspergillus japonicus LAB01 was investigated by describing the catalytic properties and stability of a secreted extracellular lipase. Enzyme production was considered high under room temperature after 4 days using sunflower oil and a combination of casein with sodium nitrate. Lipase was partially purified by 3.9-fold, resulting in a 44.2% yield using ammonium sulphate precipitation (60%) quantified with Superose 12 HR gel filtration chromatography. The activity of the enzyme was maximised at pH 8.5, and the enzyme demonstrated stability under alkaline conditions. The optimum temperature was found to be 45°C, and the enzyme was stable for up to 100 minutes, with more than 80% of initial activity remaining after incubation at this temperature. Partially purified enzyme showed reasonable stability with triton X-100 and was activated in the presence of organic solvents (toluene, hexane, and methanol). Among the tested ions, only Cu(2+), Ni(2+), and Al(3+) showed inhibitory effects. Substrate specificity of the lipase was higher for C14 among various p-nitrophenyl esters assayed. The KM and V max values of the purified enzyme for p-nitrophenyl palmitate were 0.13 mM and 12.58 umol/(L·min), respectively. These features render a novel biocatalyst for industrial applications.


Assuntos
Aspergillus/enzimologia , Lipase/isolamento & purificação , Estabilidade Enzimática , Ésteres/química , Helianthus/química , Concentração de Íons de Hidrogênio , Lipase/química , Lipólise , Óleos de Plantas/química , Solventes/química , Especificidade por Substrato , Temperatura
4.
PLoS Negl Trop Dis ; 8(4): e2764, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24699271

RESUMO

BACKGROUND: The present study analyzed whether or not the in vitro cultivation for long periods of time of pre-isolated Leishmania amazonensis from lesions of chronically infected BALB/c mice was able to interfere in the parasites' infectivity using in vivo and in vitro experiments. In addition, the proteins that presented a significant decrease or increase in their protein expression content were identified applying a proteomic approach. METHODOLOGY/PRINCIPAL FINDINGS: Parasites were cultured in vitro for 150 days. Aliquots were collected on the day 0 of culture (R0), as well as after ten (R10; 50 days of culture), twenty (R20; 100 days of culture), and thirty (R30; 150 days of culture) passages, and were used to analyze the parasites' in vitro and in vivo infectivity, as well as to perform the proteomic approach. Approximately 837, 967, 935, and 872 spots were found in 2-DE gels prepared from R0, R10, R20, and R30 samples, respectively. A total of 37 spots presented a significant decrease in their intensity of expression, whereas a significant increase in protein content during cultivation could be observed for 19 proteins (both cases >2.0 folds). Some of these identified proteins can be described, such as diagnosis and/or vaccine candidates, while others are involved in the infectivity of Leishmania. It is interesting to note that six proteins, considered hypothetical in Leishmania, showed a significant decrease in their expression and were also identified. CONCLUSIONS/SIGNIFICANCE: The present study contributes to the understanding that the cultivation of parasites over long periods of time may well be related to the possible loss of infectivity of L. amazonensis. The identified proteins that presented a significant decrease in their expression during cultivation, including the hypothetical, may also be related to this loss of parasites' infectivity, and applied in future studies, including vaccine candidates and/or immunotherapeutic targets against leishmaniasis.


Assuntos
Perfilação da Expressão Gênica , Leishmania mexicana/química , Leishmania mexicana/patogenicidade , Proteoma/análise , Proteínas de Protozoários/análise , Fatores de Virulência/análise , Adaptação Biológica , Animais , Eletroforese em Gel Bidimensional , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Proteínas de Protozoários/genética , Inoculações Seriadas , Virulência , Fatores de Virulência/genética
6.
Clin Vaccine Immunol ; 20(6): 835-41, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23554466

RESUMO

In Brazil, the percentage of infected dogs living in areas where canine visceral leishmaniasis (CVL) is endemic ranges from 10 to 62%; however, the prevalence of infection in dogs is probably higher than figures reported from serological studies. In addition, problems with the occurrence of false-positive or false-negative results in the serodiagnosis of CVL have been reported. The present work analyzed the potential of synthetic peptides mapped from hypothetical proteins for improvement of the serodiagnosis of Leishmania infantum infection in dogs. From 26 identified leishmanial proteins, eight were selected, considering that no homologies between these proteins and others from trypanosomatide sequence databases were encountered. The sequences of these proteins were mapped to identify linear B-cell epitopes, and 17 peptides were synthesized and tested in enzyme-linked immunosorbent assays (ELISAs) for the serodiagnosis of L. infantum infection in dogs. Of these, three exhibited sensitivity and specificity values higher than 75% and 90%, respectively, to differentiate L. infantum-infected animals from Trypanosoma cruzi-infected animals and healthy animals. Soluble Leishmania antigen (SLA) showed poor sensitivity (4%) and specificity (36%) to differentiate L. infantum-infected dogs from healthy and T. cruzi-infected dogs. Lastly, the three selected peptides were combined in different mixtures and higher sensitivity and specificity values were obtained, even when sera from T. cruzi-infected dogs were used. The study's findings suggest that these three peptides can constitute a potential tool for more sensitive and specific serodiagnosis of L. infantum infection in dogs.


Assuntos
Anticorpos Antiprotozoários/sangue , Doenças do Cão/diagnóstico , Leishmania infantum/imunologia , Leishmaniose Visceral/veterinária , Peptídeos , Medicina Veterinária/métodos , Animais , Brasil , Biologia Computacional/métodos , Doenças do Cão/parasitologia , Cães , Ensaio de Imunoadsorção Enzimática/métodos , Leishmaniose Visceral/diagnóstico , Leishmaniose Visceral/parasitologia , Sensibilidade e Especificidade , Testes Sorológicos/métodos
7.
PLoS Negl Trop Dis ; 7(3): e2148, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23573301

RESUMO

BACKGROUND: The present study aimed to evaluate a hypothetical Leishmania amastigote-specific protein (LiHyp1), previously identified by an immunoproteomic approach performed in Leishmania infantum, which showed homology to the super-oxygenase gene family, attempting to select a new candidate antigen for specific serodiagnosis, as well as to compose a vaccine against VL. METHODOLOGY/PRINCIPAL FINDINGS: The LiHyp1 DNA sequence was cloned; the recombinant protein (rLiHyp1) was purified and evaluated for its antigenicity and immunogenicity. The rLiHyp1 protein was recognized by antibodies from sera of asymptomatic and symptomatic animals with canine visceral leishmaniasis (CVL), but presented no cross-reactivity with sera of dogs vaccinated with Leish-Tec, a Brazilian commercial vaccine; with Chagas' disease or healthy animals. In addition, the immunogenicity and protective efficacy of rLiHyp1 plus saponin was evaluated in BALB/c mice challenged subcutaneously with virulent L. infantum promastigotes. rLiHyp1 plus saponin vaccinated mice showed a high and specific production of IFN-γ, IL-12, and GM-CSF after in vitro stimulation with the recombinant protein. Immunized and infected mice, as compared to the control groups (saline and saponin), showed significant reductions in the number of parasites found in the liver, spleen, bone marrow, and in the paws' draining lymph nodes. Protection was associated with an IL-12-dependent production of IFN-γ, produced mainly by CD4 T cells. In these mice, a decrease in the parasite-mediated IL-4 and IL-10 response could also be observed. CONCLUSIONS/SIGNIFICANCE: The present study showed that this Leishmania oxygenase amastigote-specific protein can be used for a more sensitive and specific serodiagnosis of asymptomatic and symptomatic CVL and, when combined with a Th1-type adjuvant, can also be employ as a candidate antigen to develop vaccines against VL.


Assuntos
Antígenos de Protozoários/imunologia , Leishmania infantum/imunologia , Leishmaniose Visceral/prevenção & controle , Oxigenases/imunologia , Vacinas Sintéticas/imunologia , Estruturas Animais/parasitologia , Animais , Antígenos de Protozoários/genética , Antígenos de Protozoários/isolamento & purificação , Linfócitos T CD4-Positivos/imunologia , Clonagem Molecular , Reações Cruzadas , Modelos Animais de Doenças , Doenças do Cão/imunologia , Doenças do Cão/parasitologia , Cães , Imunoensaio/métodos , Interferon gama/metabolismo , Interleucina-12/metabolismo , Leishmaniose/imunologia , Leishmaniose/prevenção & controle , Leishmaniose/veterinária , Leishmaniose Visceral/imunologia , Camundongos , Camundongos Endogâmicos BALB C , Oxigenases/genética , Oxigenases/isolamento & purificação , Carga Parasitária , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Proteínas Recombinantes/isolamento & purificação , Vacinas Sintéticas/administração & dosagem , Vacinas Sintéticas/genética
8.
Parasitol Res ; 111(4): 1807-16, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22797606

RESUMO

The development of therapeutic alternatives to treat leishmaniasis has received considerable attention. The present study aimed to investigate the efficacy of the Agaricus blazei Murill water extract (AbM) to treat BALB/c mice infected with Leishmania amazonensis. First, a dose-titration curve was performed. The most well-defined concentration able to induce the most effective results in the infected animals, considering a daily administration of the product, was that of 100 mg kg(-1) day(-1). In this context, the AbM was administered orally, beginning on day 0 up to 20 days postinfection. Additional animals were treated with amphotericin B (AmpB, 5 mg kg(-1) day(-1)) by peritoneal route for the same period of time, while the control group received distilled water. The animals were evaluated at 14 weeks post-infection, at which time the parasitological and immunological parameters were analyzed. Mice treated with the AbM presented a 60% reduction in the inflammation of infected footpads as compared to untreated control-infected mice. Moreover, in the treated mice, as compared to the untreated controls, approximately 60 and 66% reductions could be observed in the parasite burdens of the footpad and draining lymph nodes, respectively. In addition, no parasites could be detected in the spleen of treated mice at week 14 postinfection. These treated animals produced significantly higher levels of interferon gamma (IFN-γ) and nitric oxide (NO), higher levels of parasite-specific IgG2a isotype antibodies, and lower levels of interleukin (IL)-4, and IL-10 in the spleen and lymph node cell cultures than did the controls. Differences could be observed by comparing animals treated with AbM to those treated with AmpB, as indicated by a significant reduction in tissue parasitism, higher levels of IFN-γ and NO, and lower levels of IL-4 and IL-10, as well as by a decreased hepatic toxicity. In conclusion, the present study's data show that the A. blazei Murill water extract presents a high potential for the treatment of leishmaniasis, although additional studies on mice, as well as on other mammal hosts, are warranted in an attempt to determine this extract's true efficacy as compared to other known therapeutic products.


Assuntos
Agaricus/química , Produtos Biológicos/administração & dosagem , Leishmaniose/tratamento farmacológico , Administração Oral , Animais , Antiprotozoários/administração & dosagem , Antiprotozoários/isolamento & purificação , Produtos Biológicos/isolamento & purificação , Citocinas/metabolismo , Modelos Animais de Doenças , Feminino , Pé/parasitologia , Humanos , Leishmania/isolamento & purificação , Leishmaniose/parasitologia , Leishmaniose/patologia , Fígado/parasitologia , Linfonodos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/metabolismo , Carga Parasitária , Resultado do Tratamento
9.
Exp Parasitol ; 132(2): 228-36, 2012 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22824583

RESUMO

The present study aimed to investigate the in vitro antileishmanial activity of five fractions obtained from Agaricus blazei water extract (AbM), namely, Fab1, Fab2, Fab3, Fab4, and Fab5; and use the selected leishmanicidal fraction to treat BALB/c mice infected with Leishmania chagasi. A curve dose-titration was performed to obtain the concentration to be test in infected animals. In this context, Fab5 fraction and AbM were used in the doses of 20 and 100 mg/kg/day, respectively, with the product been administered once a day. The effect induced by a chemo-prophylactic regimen, based on the administration Fab5 fraction and AbM 5 days before infection, and maintained for an additional 20 days post-infection was compared to a therapeutic regimen, in which the compounds were administered from 0 to 20 days of infection. Control animals were either treated with amphotericin B deoxycholate (AmpB) or received distilled water. All groups were followed up for 10 weeks post-infection, when parasitological and immunological parameters were analyzed. The Fab5 presented the best results of in vitro leishmanicidal activity. In the in vivo experiments, the use of Fab5 or AbM, as compared to control groups, resulted in significant reduced parasite burdens in the liver, spleen, and draining lymph nodes of the infected animals, as compared to control groups. A Type 1 immune response was observed in the Fab5 or AbM treated animals. No significant toxicity was observed. The chemo-prophylactic regimen proved to be more effective to induce theses responses. In this context, the data presented in this study showed the potential of the purified Fab5 fraction of AbM as a therapeutic alternative to treat visceral leishmaniasis. In addition, it can be postulated that this fraction can be also employed in a chemo-prophylactic regimen associated or not with other therapeutic products.


Assuntos
Agaricus/química , Antiprotozoários/farmacologia , Leishmania infantum/efeitos dos fármacos , Leishmaniose Visceral/tratamento farmacológico , Animais , Antiprotozoários/isolamento & purificação , Antiprotozoários/uso terapêutico , Citocinas/análise , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Hemólise/efeitos dos fármacos , Concentração Inibidora 50 , Leishmaniose Visceral/prevenção & controle , Fígado/parasitologia , Linfonodos/parasitologia , Macrófagos Peritoneais/efeitos dos fármacos , Macrófagos Peritoneais/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Organismos Livres de Patógenos Específicos , Baço/imunologia , Baço/parasitologia
10.
Parasitol Int ; 60(4): 357-63, 2011 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21723957

RESUMO

Leishmaniasis is a major public health problem, and the alarming spread of parasite resistance underlines the importance of discovering new therapeutic products. The present study aims to investigate the in vitro leishmanicidal activity of an Agaricus blazei Murill mushroom extract as compared to different Leishmania species and stages. The water extract proved to be effective against promastigote and amastigote-like stages of Leishmania amazonensis, L. chagasi, and L. major, with IC(50) (50% inhibitory concentration) values of 67.5, 65.8, and 56.8 µg/mL for promastigotes, and 115.4, 112.3, and 108.4 µg/mL for amastigotes-like respectively. The infectivity of the three Leishmania species before and after treatment with the water extract was analyzed, and it could be observed that 82%, 57%, and 73% of the macrophages were infected with L. amazonensis, L. major, and L. chagasi, respectively. However, when parasites were pre-incubated with the water extract, and later used to infect macrophages, they were able to infect only 12.7%, 24.5%, and 19.7% of the phagocytic cells for L. amazonensis, L. chagasi, and L. major, respectively. In other experiments, macrophages were infected with L. amazonensis, L. chagasi, or L. major, and later treated with the aforementioned extract, presented reductions of 84.4%, 79.6%, and 85.3% in the parasite burden after treatment. A confocal microscopy revealed the loss of the viability of the parasites within the infected macrophages after treatment with the water extract. The applied extract presented a low cytotoxicity in murine macrophages and a null hemolytic activity in type O(+) human red blood cells. No nitric oxide (NO) production, nor inducible nitric oxide syntase expression, could be observed in macrophages after stimulation with the water extract, suggesting that biological activity may be due to direct mechanisms other than macrophage activation by means of NO production. In conclusion, the results demonstrate that the A. blazei Murill water extract can potentially be used as a therapeutic alternative on its own, or in association with other drugs, to treat Visceral and Cutaneous Leishmaniasis.


Assuntos
Agaricus/química , Misturas Complexas/farmacologia , Leishmania major/efeitos dos fármacos , Leishmania mexicana/efeitos dos fármacos , Leishmania/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Leishmaniose Visceral/tratamento farmacológico , Macrófagos/efeitos dos fármacos , Animais , Células Cultivadas , Misturas Complexas/química , Misturas Complexas/uso terapêutico , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Feminino , Hemólise/efeitos dos fármacos , Humanos , Leishmania/crescimento & desenvolvimento , Leishmania major/crescimento & desenvolvimento , Leishmania mexicana/crescimento & desenvolvimento , Leishmaniose Cutânea/parasitologia , Leishmaniose Visceral/parasitologia , Macrófagos/citologia , Macrófagos/parasitologia , Camundongos , Camundongos Endogâmicos BALB C , Óxido Nítrico/análise , Óxido Nítrico Sintase Tipo II/metabolismo , Água
11.
Arch Biochem Biophys ; 436(1): 168-77, 2005 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-15752722

RESUMO

The work in the literature on apomyoglobin is almost equally divided between horse and sperm whale myoglobins. The two proteins share high homology, show similar folding behavior, and it is often assumed that all folding phenomena found with one protein will also be found with the other. We report data at equilibrium showing that horse myoglobin was 2.1 kcal/mol less stable than sperm whale myoglobin at pH 5.0, and aggregated at high concentrations as measured by gel filtration and analytical ultracentrifugation experiments. The higher stability of sperm whale myoglobin was identified for both apo and holo forms, and was independent of pH from 5 to 8 and of the presence of sodium chloride. We also show that the substitution of sperm whale myoglobin residues Ala15 and Ala74 to Gly, the residues found at positions 15 and 74 in horse myoglobin, decreased the stability by 1.0 kcal/mol, indicating that helix propensity is an important component of the explanation for the difference in stability between the two proteins.


Assuntos
Mioglobina/química , Dobramento de Proteína , Animais , Sequência de Bases , Cromatografia em Gel , Relação Dose-Resposta a Droga , Cavalos , Concentração de Íons de Hidrogênio , Dados de Sequência Molecular , Mioglobina/metabolismo , Desnaturação Proteica , Especificidade da Espécie , Temperatura , Ultracentrifugação , Ureia/farmacologia , Baleias
12.
Arch Biochem Biophys ; 427(2): 135-42, 2004 Jul 15.
Artigo em Inglês | MEDLINE | ID: mdl-15196987

RESUMO

We report here on the stability and folding of the 91 residue alpha-helical F29W N-terminal domain of chicken skeletal muscle troponin C (TnC(1-91)F29W), the thin filament calcium-binding component. Unfolding was monitored by differential scanning calorimetry, circular dichroism, and intrinsic fluorescence spectroscopy using urea, pH, and temperature as denaturants, in the absence and in the presence of calcium. The unfolding of TnC(1-91)F29W was reversible and did not follow a two-state transition, suggesting that an intermediate may be present during this reaction. Our results support the hypothesis that intermediates are likely to occur during the folding of small proteins and domains. The physiological significance of the presence of an intermediate in the folding pathway of troponin C is discussed.


Assuntos
Cálcio/química , Troponina C/química , Ureia/química , Concentração de Íons de Hidrogênio , Mutagênese Sítio-Dirigida , Conformação Proteica , Desnaturação Proteica , Dobramento de Proteína , Estrutura Terciária de Proteína , Temperatura
13.
J Biol Chem ; 279(13): 13018-26, 2004 Mar 26.
Artigo em Inglês | MEDLINE | ID: mdl-14715660

RESUMO

Amphibian skin secretions constitute an important source of molecules for antimicrobial drug research in order to combat the increasing resistance of pathogens to conventional antibiotics. Among the various types of substances secreted by the dermal granular amphibian glands, there is a wide range of peptides and proteins, often displaying potent antimicrobial activities and providing an effective defense system against parasite infection. In the present work, we report the NMR solution structure and the biological activity of a cationic 14-residue amphiphilic alpha-helical polypeptide named Hylaseptin P1 (HSP1), isolated from the skin secretion of the hylid frog Hyla punctata. The peptide antimicrobial activity was verified against Candida albicans, Staphylococcus aureus, Escherichia coli, and Pseudomonas aeruginosa, whereas no significant lytic effect was detected toward red or white blood cells.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Anuros/metabolismo , Pele/metabolismo , Sequência de Aminoácidos , Animais , Candida albicans/metabolismo , Cromatografia Líquida de Alta Pressão , Dicroísmo Circular , Relação Dose-Resposta a Droga , Eritrócitos/efeitos dos fármacos , Escherichia coli/metabolismo , Íons , Leucócitos/efeitos dos fármacos , Espectroscopia de Ressonância Magnética , Espectrometria de Massas , Microscopia de Força Atômica , Modelos Moleculares , Dados de Sequência Molecular , Peptídeos/química , Conformação Proteica , Prótons , Pseudomonas aeruginosa/metabolismo , Staphylococcus aureus/metabolismo , Fatores de Tempo
14.
Biopolymers ; 69(4): 470-9, 2003 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12879493

RESUMO

The hemoglobin from Biomphalaria glabrata is an extracellular respiratory protein of high molecular mass composed by subunits of 360 kDa, each one containing two 180 kDa chains linked by disulfide bridges. In this work, small angle x-ray scattering (SAXS) measurements were performed with the hemoglobin at pH 5.0 and 7.5. Radii of gyration of 98.6 +/- 0.5 and 101.8 +/- 0.2 A and maximum diameters of 300 +/- 10 and 305 +/- 10 A, respectively, were obtained from Guinier plot extrapolation and analytical curve fitting. The pair distance distribution functions p(r) corresponded to globular particles with a somewhat anisotropic shape for both preparations. Computer analysis of the low angle part of the scattering curve led to the determination of the low resolution envelope of the protein, revealing a P(222) symmetry. Shape reconstruction from ab initio calculations using the complete scattering curve furnished a compact prolate three-dimensional (3D) bead model for the protein. Hydrodynamic parameters were obtained from experiments and theoretical calculations using the 3D model. The results of the structural and biochemical studies reported herein indicate that the multisubunit structure of this hemoglobin is compatible with a tetrameric arrangement.


Assuntos
Biomphalaria/química , Hemoglobinas/química , Difração de Raios X/métodos , Animais , Hemolinfa/química , Conformação Proteica
15.
Protein Expr Purif ; 28(1): 202-8, 2003 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-12651126

RESUMO

As molecular biology has developed it has become possible to abundantly produce heterologous proteins in bacteria and to design serial amino acid substitutions for the generation of modified proteins, an approach also known as protein engineering. Sperm whale myoglobin, a protein of broad interest, has been cloned for several years now and a large collection of mutants has been produced. The presence of heme stabilizes the protein, which is recovered soluble from the bacterial pellet, and most purification protocols take advantage of this property for myoglobin purification directly from the pellet. However, recovery from the column resin is poor with these methods making them expensive and the procedure for removing heme is laborious and drastic when the apo form of Mb is required. In the case of proteins with severe mutations, which bind heme weakly or do not bind it at all, such methods cannot be employed without massive loss of productivity. Here, we describe a modified method, which is both low cost and rapid, for the purification of the soluble apo form of Mb from Escherichia coli inclusion bodies. Biophysical characterization of the protein after purification shows that the purified apoMb retains its native conformation and is soluble. This modified method is also used for the purification of a non-heme-binding apoMb mutant, demonstrating its efficiency when dealing with drastic mutations.


Assuntos
Apoproteínas/isolamento & purificação , Heme/metabolismo , Mutação/genética , Mioglobina/genética , Mioglobina/isolamento & purificação , Sequência de Aminoácidos , Animais , Apoproteínas/química , Dados de Sequência Molecular , Mioglobina/química , Mioglobina/metabolismo , Subunidades Proteicas , Proteínas Recombinantes/química , Proteínas Recombinantes/isolamento & purificação , Proteínas Recombinantes/metabolismo , Fatores de Tempo , Baleias
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