Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 17 de 17
Filtrar
Más filtros










Base de datos
Intervalo de año de publicación
1.
Behav Sci (Basel) ; 14(2)2024 Feb 08.
Artículo en Inglés | MEDLINE | ID: mdl-38392474

RESUMEN

In the post-COVID-19 era, the content of work and the necessary skills are rapidly changing due to the digital transformation of the way people work. Entrepreneurial adaptability and digital capability are the most necessary competencies for exploring opportunities and quickly turning them into a professional career amid a crisis. Financial literacy is also essential for expanding skills in economic and social life. The purpose of this study is to verify the influence of university students' financial literacy and digital capability on entrepreneurial intention and the mediating effect of entrepreneurship. To this end, a survey was conducted on university students in Busan and Gyeongnam, and a sample of 162 respondents was verified using SPSS 28.0. As a result of the study, it was found that financial literacy had a partially positive effect on entrepreneurship and entrepreneurial intention. Digital capability was found to have a positive effect on entrepreneurship and entrepreneurial intention. It was found that entrepreneurship had a partially positive effect on entrepreneurial intention. It was found that entrepreneurship had a partially positive mediating effect between financial literacy and entrepreneurial intention. It was found that entrepreneurship had a positive mediating effect between digital capability and entrepreneurial intention. As a result of this study, it was confirmed that financial literacy, digital capability, and entrepreneurship are very important competencies for university students to adapt to new trends and promote start-ups in a rapidly changing job environment after COVID-19, suggesting the need for further education.

2.
Nutrients ; 9(3)2017 Mar 16.
Artículo en Inglés | MEDLINE | ID: mdl-28300786

RESUMEN

Growing evidence has indicated that supplementation with probiotics improves lipid metabolism. We aimed to investigate the beneficial effects of a probiotics mixture (PM) of three strains belonging to the species Bifidobacterium (B. longum, B. lactis, and B. breve) and two strains belonging to the species Lactobacillus (L. reuteri and L. plantarum) on cholesterol-lowering efficacy in hypercholesterolemic rats. A hypercholesterolemic rat model was established by feeding a high-cholesterol diet for eight weeks. To test the effects of PM on hypercholesterolemia, hypercholesterolemic rats were assigned to four groups, which were treated daily with low (1.65 × 108 cfu/kg), medium (5.5 × 108 cfu/kg), or high (1.65 × 1010 cfu/kg) doses of probiotic mixture or simvastatin for eight weeks. Significant reductions of serum total cholesterol (TC), triacylglycerol (TG), and low-density lipoprotein (LDL)-cholesterol levels, but increases of high-density lipoprotein (HDL)-cholesterol were observed after supplementation of PM in hypercholesterolemic rats. In PM-supplemented hypercholesterolemic rats, hepatic tissue contents of TC and TG also significantly decreased. Notably, the histological evaluation of liver tissues demonstrated that PM dramatically decreased lipid accumulation. For their underlying mechanisms, we demonstrated that PM reduced expressions of cholesterol synthesis-related proteins such as sterol regulatory element-binding protein 1 (SREBP1), fatty acid synthase (FAS), and acetyl-CoA carboxylase (ACC) in the liver. Taken together, these findings suggest that PM has beneficial effects against hypercholesterolemia. Accordingly, our PM might be utilized as a novel therapeutic agent for the management of hypercholesterolemia.


Asunto(s)
Hipercolesterolemia/terapia , Probióticos/administración & dosificación , Acetil-CoA Carboxilasa/metabolismo , Alanina Transaminasa/sangre , Animales , Aspartato Aminotransferasas/sangre , Bifidobacterium/metabolismo , HDL-Colesterol/sangre , LDL-Colesterol/sangre , Dieta , Ácido Graso Sintasas/metabolismo , Hipercolesterolemia/sangre , Lactobacillus/metabolismo , Hígado , Masculino , Ratas , Ratas Sprague-Dawley , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/genética , Proteína 1 de Unión a los Elementos Reguladores de Esteroles/metabolismo , Triglicéridos/sangre
3.
Immune Netw ; 16(2): 140-5, 2016 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-27162531

RESUMEN

Ophiocordyceps sinensis is a natural fungus that has been valued as a health food and used in traditional Chinese medicine for centuries. The fungus is parasitic and colonizes insect larva. Naturally occurring O. sinensis thrives at high altitude in cold and grassy alpine meadows on the Himalayan mountain ranges. Wild Ophiocordyceps is becoming increasingly rare in its natural habitat, and its price limits its use in clinical practice. Therefore, the development of a standardized alternative is a great focus of research to allow the use of Ophiocordyceps as a medicine. To develop an alternative for wild Ophiocordyceps, a refined standardized extract, CBG-CS-2, was produced by artificial fermentation and extraction of the mycelial strain Paecilomyces hepiali CBG-CS-1, which originated from wild O. sinensis. In this study, we analyzed the in vitro immune-modulating effect of CBG-CS-2 on natural killer cells and B and T lymphocytes. CBG-CS-2 stimulated splenocyte proliferation and enhanced Th1-type cytokine expression in the mouse splenocytes. Importantly, in vitro CBG-CS-2 treatment enhanced the killing activity of the NK-92MI natural killer cell line. These results indicate that the mycelial culture extract prepared from Ophiocordyceps exhibits immune-modulating activity, as was observed in vivo and this suggests its possible use in the treatment of diseases caused by abnormal immune function.

4.
Orient Pharm Exp Med ; 15(1): 7-12, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-25814919

RESUMEN

Cordyceps (CS) is a traditional Chinese herb with various biological effects that include immune modulation. CBG-CS-2 is a strain, Paecilomyces hepiali, of the Cordyceps spp. The anti-inflammatory effects of CBG-CS-2 were investigated. The water-soluble fraction of CBG-CS-2 has high anti-inflammatory activity in LPS-induced Raw264.7 macrophages. We tested the role of CBG-CS-2 on the anti-inflammation cascade in LPS-stimulated Raw264.7 cells. CBG-CS-2 significantly decreased NO production, iNOS expression, and pro-inflammatory cytokine secretion in a dose-dependent manner. To investigate the mechanism by which CBG-CS-2 inhibits NO, iNOS, and pro-inflammatory cytokines, we examined the activities of NF-κB and AP-1 in LPS-activated macrophages. The results demonstrate that CBG-CS-2 suppresses the production and expression of NO, iNOS, and pro-inflammatory cytokines in LPS-activated macrophages via inhibition of NF-κB and AP-1, which may play an important role in inflammation. These findings suggest that CBG-CS-2 has modulatory effects on the inflammatory system in macrophages, and that it can serve as a useful anti-inflammatory dietary supplement or drug.

5.
Int J Med Mushrooms ; 17(12): 1189-99, 2015.
Artículo en Inglés | MEDLINE | ID: mdl-26854106

RESUMEN

Ophiocordyceps sinensis is a natural fungus that has been valued as a health food and traditional Chinese medicine for centuries. The fungus is parasitic and colonizes insect larva. Naturally occurring O. sinensis thrives at high altitude in cold and grassy alpine meadows on the Himalayan mountain ranges. Wild O. sinensis is becoming increasingly rare in its natural habitats, and its price is out of reach for clinical practice. For these reasons, development of a standardized alternative is a great focus of research to allow the use of O. sinensis as a medicine. To develop an alternative for wild O. sinensis, a refined standardized extract, CBG-CS-2, was produced by artificial fermentation and extraction of the mycelial strain Paecilomyces hepiali CBG-CS-1, which originated from wild O. sinensis. In this study, we analyzed the in vivo immune-modulating effect of CBG-CS-2 in mice. Oral administration of CBG-CS-2 supported splenocyte stimulation and enhanced Th1-type cytokine expression from the splenocytes. Importantly, the same treatment significantly enhanced the natural killer cell activity of the splenocytes. Finally, oral administration of CBG-CS-2 enhanced the potential for inflammatory responses. Together, these findings indicate that the mycelial culture extract prepared from O. sinensis exhibited immune-modulating activity and suggest its possible use in the treatment of diseases caused by abnormal immune function.


Asunto(s)
Ascomicetos/química , Productos Biológicos/aislamiento & purificación , Factores Inmunológicos/farmacología , Preparaciones Farmacéuticas/aislamiento & purificación , Animales , Productos Biológicos/farmacología , Proliferación Celular/efectos de los fármacos , Citocinas/biosíntesis , Hypocreales/química , Células Asesinas Naturales/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Micelio/crecimiento & desarrollo , Micelio/metabolismo , Bazo/citología , Bazo/efectos de los fármacos
6.
J Microbiol ; 49(3): 418-30, 2011 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-21717328

RESUMEN

Two genes encoding MAP kinase homologs, designated as mpkB and mpkC, were isolated from Aspergillus nidulans by PCR with degenerate primers. Deletion and over-expression mutants of mpkC showed no detectable phenotypes under any external stress tested. Deletion of mpkB caused pleiotropic phenotypes including a failure in forming cleistothecia under any induction conditions for sexual development, increased Hülle cell production, slow hyphal growth and aberrant conidiophore morphology. Over-expression of mpkB led to increased cleistothecium production. While the transcripts of mpkB and mpkC were constitutively synthesized through the entire life cycle, their size and amount differed with developmental stages. An outcross test using fluorescent protein reporters showed that the mpkB deletion mutant could not form heterokaryons with wild type. Protoplast fusion experiments showed that the fusant of the mpkB mutant with wild type could undergo normal sexual development. However, heterokaryotic mycelia that were produced from a fusant between two mpkB deletion mutants could not form cleistothecia, although they did appear to form diploid nuclei. These results suggest that the MpkB MAP kinase is required for some post-karyogamy process as well as at the hyphal anastomosis stage to accomplish sexual development successfully.


Asunto(s)
Aspergillus nidulans/enzimología , Aspergillus nidulans/genética , Regulación Fúngica de la Expresión Génica , Hifa/crecimiento & desarrollo , Proteínas Quinasas Activadas por Mitógenos/metabolismo , Aspergillus nidulans/crecimiento & desarrollo , Aspergillus nidulans/fisiología , Clonación Molecular , Proteínas Fúngicas/genética , Proteínas Fúngicas/metabolismo , Eliminación de Gen , Genes Fúngicos , Hifa/genética , Hifa/metabolismo , Meiosis/genética , Proteínas Quinasas Activadas por Mitógenos/genética , Datos de Secuencia Molecular , Análisis de Secuencia de ADN
7.
BMB Rep ; 42(5): 260-4, 2009 May 31.
Artículo en Inglés | MEDLINE | ID: mdl-19470238

RESUMEN

Tumor necrosis factor-alpha (TNF-alpha) exhibits cytotoxicity towards various tumor cells in vitro and induces apoptotic necrosis in transplanted tumors in vivo. It also shows severe toxicity when used systemically for the treatment of cancer patients, hampering the development of TNF-alpha as a potential anticancer drug. In order to understand the structure-function relation of TNF-alpha with respect to receptor binding, we selected four regions on the bottom of the TNF-alpha trimer that are in close contact with the receptor and carried out mutagenesis studies and computational modeling. From the study, various TNF-alpha muteins with a high therapeutic index were identified. These results will provide a structural basis for the design of highly potent TNF-alpha for therapeutic purposes. By conjugating TNF-alpha muteins with a high therapeutic index to a fusion partner, which targets a marker of angiogenesis, it could be possible to develop TNF-alpha based anticancer drugs.


Asunto(s)
Neoplasias/tratamiento farmacológico , Proteínas Recombinantes/química , Proteínas Recombinantes/uso terapéutico , Factor de Necrosis Tumoral alfa/química , Factor de Necrosis Tumoral alfa/uso terapéutico , Animales , Femenino , Humanos , Ratones , Mutagénesis Sitio-Dirigida , Receptores del Factor de Necrosis Tumoral/genética , Receptores del Factor de Necrosis Tumoral/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo
8.
BMB Rep ; 42(12): 829-33, 2009 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-20044956

RESUMEN

Angiogenin is a member of the ribonuclease superfamily that induces the formation of new blood vessels. It has been suggested that the surface loop of angiogenin defined by residues 59-71 plays a special role in angiogenic function (1); however, the mechanism of action is not clearly defined. To elucidate the role of the surface loop on the structure, function and stability of angiogenin, three surface loop mutants were produced in which 14 amino acids in the surface loop of RNase A were substituted for the 13 amino acids in the corresponding loop of angiogenin. The structure, stability and biological functions of the mutants were then investigated using biophysical and biological approaches. Even though the substitutions did not influence the overall structure of angiogenin, they affected the stability and angiogenic function of angiogenin, indicating that the surface loop of angiogenin plays a significant role in maintaining the stability and angiogenic function of angiogenin.


Asunto(s)
Ribonucleasa Pancreática/química , Ribonucleasa Pancreática/metabolismo , Estabilidad de Enzimas , Mutación , Conformación Proteica , Ribonucleasa Pancreática/genética , Relación Estructura-Actividad , Propiedades de Superficie
9.
Appl Environ Microbiol ; 72(4): 3021-5, 2006 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-16598011

RESUMEN

The three-dimensional (3D) structure of the hyperthermophilic esterase EstE1 was constructed by homology modeling using Archaeoglobus fulgidus esterase as a reference, and the thermostability-structure relationship was analyzed. Our results verified the predicted 3D structure of EstE1 and identified the ion pair networks and hydrophobic interactions that are critical determinants for the thermostability of EstE1.


Asunto(s)
Archaeoglobus fulgidus/enzimología , Esterasas/química , Esterasas/metabolismo , Calor , Estabilidad de Enzimas , Interacciones Hidrofóbicas e Hidrofílicas , Modelos Moleculares , Datos de Secuencia Molecular , Desnaturalización Proteica , Estructura Secundaria de Proteína , Alineación de Secuencia , Relación Estructura-Actividad
10.
Biotechnol Lett ; 26(19): 1501-4, 2004 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-15604787

RESUMEN

Recombinant bovine angiogenin (rbAng) was expressed in E. coli at up to 30% of total cell proteins but was produced as inclusion bodies. By investigating the effect of various factors on the refolding yield, we obtained about 60% refolding. After chromatographic purification, about 60 mg purified angiogenin was obtained from 1 l culture. The purified recombinant bovine angiogenin was identical to native bovine angiogenin (nbAng) obtained from cow's milk. Our approach is highly efficient and can be generally used for the production of various types of angiogenin for functional and structural studies as well as therapeutic purposes.


Asunto(s)
Técnicas de Cultivo de Célula/métodos , Escherichia coli/genética , Escherichia coli/metabolismo , Neovascularización Fisiológica/efectos de los fármacos , Ingeniería de Proteínas/métodos , Ribonucleasa Pancreática/biosíntesis , Ribonucleasa Pancreática/farmacología , Animales , Bovinos , Movimiento Celular/efectos de los fármacos , Células Cultivadas , Pollos , Membrana Corioalantoides/irrigación sanguínea , Membrana Corioalantoides/efectos de los fármacos , Células Endoteliales/efectos de los fármacos , Células Endoteliales/fisiología , Humanos , Cuerpos de Inclusión/metabolismo , Pliegue de Proteína , Proteínas Recombinantes/biosíntesis , Proteínas Recombinantes/química , Proteínas Recombinantes/farmacología , Ribonucleasa Pancreática/química , Ribonucleasa Pancreática/genética , Cicatrización de Heridas/efectos de los fármacos
11.
J Pept Sci ; 10(5): 304-11, 2004 May.
Artículo en Inglés | MEDLINE | ID: mdl-15160843

RESUMEN

The antinematodal activity and mechanism of a 23-mer antimicrobial peptide, PMAP-23, derived from pig myeloid was investigated. PMAP-23 displayed a strong antinematodal activity against the eggs and worms of Caenorhabditis elegans. To investigate the antinematodal mechanism of PMAP-23, fluorescence activated flow cytometry and confocal laser scanning microscopy were performed. C. elegans treated with PMAP-23 showed higher fluorescence intensity by propidium iodide (PI) staining than normal cells. Confocal microscopy showed that the peptide was localized in the egg's shell and cell membrane. The action of the peptide against C. elegans membranes was examined by testing the membrane disrupting activity using liposome (PC/PS; 3:1, w/w). The result suggests that PMAP-23 may exert its antinematodal activity by disrupting the structure of the cell membrane via pore formation or via direct interaction with the lipid bilayers.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/farmacología , Antinematodos/farmacología , Caenorhabditis elegans/efectos de los fármacos , Membrana Celular/efectos de los fármacos , Huevos , Animales , Caenorhabditis elegans/crecimiento & desarrollo , Membrana Dobles de Lípidos , Porcinos
12.
Biotechnol Lett ; 26(6): 493-8, 2004 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-15127790

RESUMEN

To develop novel antibiotic peptides useful as therapeutic drugs, a number of analogues were designed to increase the hydrophobic helix region either by Trp-substitution or net positive charge increase by Lys-substitution, from HP(2-9)-ME(1-12). The antibiotic activities of these peptides were evaluated using bacterial (Salmonella tryphimurium, Proteus vulgaris, Bacillus subtilis and Staphylococcus aureus), fungi (Saccharomyces cerevisiae, Trichosporon beigelii and Candida albicans), tumor and human erythrocyte cells. The substitution of Lys for Thr at position 18 and 19 of HP(2-9)-ME(1-12) (HM5) increased activity against Proteus vulgaris and fungal strains without hemolysis. In contrast, substitution of Trp for Lys and Thr at positions 2, 15 and 19 of HP(2-9)-ME(1-12), respectively (HM3 and HM4), decreased activity but increased hemolysis against human erythrocytes. This suggests that an increase in positive charge increases antimicrobial activity whereas an increase in hydrophobicity by introducing Trp residues at C-terminus of HP(2-9)-ME(1-12) causes a hemolytic effect. Circular dichroism spectra suggested that the alpha-helical structure of these peptides plays an important role in their antibiotic effect but that the alpha-helical property is not connected with the enhanced antibiotic activity.


Asunto(s)
Antibacterianos/química , Proteínas Bacterianas/química , Diseño de Fármacos , Meliteno/análogos & derivados , Meliteno/química , Péptidos , Proteínas Ribosómicas/química , Antibacterianos/síntesis química , Proteínas Bacterianas/síntesis química , Helicobacter pylori/química , Meliteno/síntesis química , Pruebas de Sensibilidad Microbiana , Estructura Secundaria de Proteína , Proteínas Ribosómicas/síntesis química , Relación Estructura-Actividad
13.
Biotechnol Lett ; 26(4): 287-91, 2004 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-15055763

RESUMEN

The peptide HP (2-20), derived from the N-terminal sequence of Helicobacter pylori ribosomal protein L1 (RPL1), has a nematicidal activity against eggs and worms of Caenorhabditis elegans. Eggs treated with HP (2-20) (69%) has a higher fluorescence intensity with propidium iodide staining, which was similar to that of melittin (82%) but higher than untreated cells (5.7%). Confocal microscopy showed that the peptides were located in the shell of the eggs and the inner and outer surfaces of the worms. HP (2-20) therefore may exert its antinematodal activity by disrupting the structure of the egg's shell and the cell membrane via pore formation or by direct interaction with the lipid bilayers in a detergent-like manner.


Asunto(s)
Antinematodos/farmacología , Proteínas Bacterianas/farmacología , Fragmentos de Péptidos/farmacología , Animales , Antiinfecciosos/farmacología , Caenorhabditis elegans , Detergentes/farmacología , Citometría de Flujo , Helicobacter pylori/metabolismo , Membrana Dobles de Lípidos/química , Meliteno/farmacología , Microscopía Confocal , Péptidos/química , Péptidos/farmacología , Propidio/farmacología
14.
Biochem Biophys Res Commun ; 305(2): 305-10, 2003 May 30.
Artículo en Inglés | MEDLINE | ID: mdl-12745074

RESUMEN

The fungicidal effect and mechanism of a tryptophan-rich 13-mer peptide, indolicidin derived from granules of bovine neutrophils, were investigated. Indolicidin displayed a strong fungicidal activity against various fungi. In order to understand the fungicidal mechanism(s) of indolicidin, we examined the interaction of indolicidin with the pathogenic fungus Trichosporon beigelii. Fluorescence confocal microscopy and flow cytometry analysis revealed that indolicidin acted rapidly on the plasma membrane of the fungal cells in an energy-independent manner. This interaction is also dependent on the ionic environment. Furthermore, indolicidin caused significant morphological changes when tested for the membrane disrupting activity using liposomes (phosphatidylcholine/cholesterol; 10:1, w/w). The results suggest that indolicidin may exert its fungicidal activity by disrupting the structure of cell membranes, via direct interaction with the lipid bilayers, in a salt-dependent and energy-independent manner.


Asunto(s)
Antifúngicos/farmacología , Péptidos Catiónicos Antimicrobianos/farmacología , Fosfolípidos/metabolismo , Secuencia de Aminoácidos , Antifúngicos/síntesis química , Antifúngicos/química , Péptidos Catiónicos Antimicrobianos/síntesis química , Péptidos Catiónicos Antimicrobianos/química , Membrana Celular/efectos de los fármacos , Membrana Celular/ultraestructura , Permeabilidad de la Membrana Celular/efectos de los fármacos , Colesterol , Citometría de Flujo , Liposomas/química , Microscopía Confocal , Datos de Secuencia Molecular , Fosfatidilcolinas , Sales (Química)/farmacología , Trichosporon/efectos de los fármacos , Trichosporon/metabolismo , Trichosporon/ultraestructura
15.
Biochim Biophys Acta ; 1645(2): 172-82, 2003 Feb 21.
Artículo en Inglés | MEDLINE | ID: mdl-12573247

RESUMEN

To develop novel antibiotic peptides useful as therapeutic drugs, the analogues were designed to increase not only net positive charge by Lys substitution but also hydrophobic helix region by Leu substitution from cecropin A (1-8)-magainin 2 (1-12) hybrid peptide (CA-MA). In particular, CA-MA analogue P5 (P5), designed by flexible region (GIG-->P) substitution, Lys (positions 4, 8, 14, 15) and Leu (positions 5, 6, 12, 13, 16, 17, 20) substitutions, showed an enhanced antimicrobial and antitumor activity without hemolysis. Confocal microscopy showed that P5 was located in the plasma membrane. The antibacterial effects of analogues were further confirmed by using 1,6-diphenyl-1,3,5-hexatriene as a plasma membrane probe. Flow cytometric analysis revealed that P5 acted in an energy-independent manner. This interaction is also independent of the ionic environment. Furthermore, P5 causes significant morphological alterations of the bacterial surfaces as shown by scanning electron microscopy and showed strong membrane disrupting activity when examined using liposomes (phosphatidyl choline/cholesterol; 10:1, w/w). Its potent antibiotic activity suggests that P5 is an excellent candidate as a lead compound for the development of novel antiinfective agents.


Asunto(s)
Péptidos Catiónicos Antimicrobianos/química , Péptidos Catiónicos Antimicrobianos/farmacología , Diseño de Fármacos , Secuencia de Aminoácidos , Antiinfecciosos/farmacología , Péptidos Catiónicos Antimicrobianos/síntesis química , Antineoplásicos/farmacología , Candida albicans/efectos de los fármacos , Supervivencia Celular/efectos de los fármacos , Difenilhexatrieno , Citometría de Flujo , Fluoresceína-5-Isotiocianato , Leucina/química , Lisina/química , Pruebas de Sensibilidad Microbiana , Microscopía Confocal , Datos de Secuencia Molecular , Azida Sódica , Células Tumorales Cultivadas/efectos de los fármacos
16.
Mol Cells ; 16(3): 323-30, 2003 Dec 31.
Artículo en Inglés | MEDLINE | ID: mdl-14744022

RESUMEN

Insulin contains two inter-chain disulfide bonds between the A and B chains (A7-B7 and A20-B19), and one intra-chain linkage in the A chain (A6-A11). To investigate the role of each disulfide bond in the structure, function and stability of the molecule, three des mutants of human insulin, each lacking one of the three disulfide bonds, were prepared by enzymatic conversion of refolded mini-proinsulins. Structural and biological studies of the three des mutants revealed that all three disulfide bonds are essential for the receptor binding activity of insulin, whereas the different disulfide bonds make different contributions to the overall structure of insulin. Deletion of the A20-B19 disulfide bond had the most substantial influence on the structure as indicated by loss of ordered secondary structure, increased susceptibility to proteolysis, and markedly reduced compactness. Deletion of the A6-A11 disulfide bond caused the least perturbation to the structure. In addition, different refolding efficiencies between the three des mutants suggest that the disulfide bonds are formed sequentially in the order A20-B19, A7-B7 and A6-A11 in the folding pathway of proinsulin.


Asunto(s)
Cistina/metabolismo , Insulina/química , Cromatografía Líquida de Alta Presión , Dicroismo Circular , Cistina/genética , Electroforesis en Gel de Poliacrilamida , Humanos , Insulina/genética , Insulina/metabolismo , Mutación , Proinsulina/genética , Proinsulina/metabolismo , Unión Proteica , Pliegue de Proteína , Receptor de Insulina/metabolismo
17.
J Pept Sci ; 8(8): 453-60, 2002 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12212808

RESUMEN

The fungicidal effects of the peptide HP (2-20). derived from the N-terminal sequence of Helicobacter pylori ribosomal protein L1 (RPL1). have been investigated. HP (2-20) displays a strong fungicidal activity against various fungi, without haemolytic activity against human erythrocyte cells, and the fungicidal activity is inhibited by Ca2+ and Mg2+ ions. In order to investigate the fungicidal mechanism(s) of HP (2-20). the amount of intracellular trehalose was measured in C. albicans. It was found that the amounts of intracellular trehalose were decreased when HP (2-20) was used. The action of the peptide against fungal cell membranes was further examined by the potassium-release test; HP (2-20) was found to increase the amount of K+ released from the cells. Furthermore, HP (2-20) caused significant morphological changes, as shown by scanning electron microscopy, and by testing the membrane disrupting activity using liposomes (phosphatidyl choline/cholesterol; 10: 1, w/w). Our results suggest that HP (2-20) may exert its antifungal activity by disrupting the structure of cell membranes, via pore formation or direct interaction with the lipid bilayers.


Asunto(s)
Antifúngicos/farmacología , Proteínas Bacterianas/farmacología , Candida albicans/efectos de los fármacos , Fragmentos de Péptidos/farmacología , Secuencia de Aminoácidos , Antifúngicos/química , Proteínas Bacterianas/química , Candida albicans/ultraestructura , Membrana Celular/efectos de los fármacos , Membrana Celular/ultraestructura , Helicobacter pylori/química , Humanos , Técnicas In Vitro , Meliteno/química , Meliteno/farmacología , Microscopía Electrónica de Rastreo , Datos de Secuencia Molecular , Fragmentos de Péptidos/química , Proteínas Ribosómicas/química
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...