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1.
Sci Adv ; 6(14): eaaz0421, 2020 04.
Artigo em Inglês | MEDLINE | ID: mdl-32284978

RESUMO

Blue natural pigments are rare, especially among plants. However, flowering species that evolved to attract Hymenoptera pollinators are colored by blue anthocyanin-metal complexes. Plants lacking anthocyanins are pigmented by betalains but are unable to produce blue hues. By extending the π-system of betalains, we designed a photostable and metal-free blue dye named BeetBlue that did not show toxicity to human hepatic and retinal pigment epithelial cells and does not affect zebrafish embryonal development. This chiral dye can be conveniently synthesized from betalamic acid obtained from hydrolyzed red beetroot juice or by enzymatic oxidation of l-dopa. BeetBlue is blue in the solid form and in solution of acidified polar molecular solvents, including water. Its capacity to dye natural matrices makes BeetBlue the prototype of a new class of low-cost bioinspired chromophores suitable for a myriad of applications requiring a blue hue.


Assuntos
Corantes/química , Corantes/isolamento & purificação , Pigmentos Biológicos/química , Plantas/química , Animais , Fenômenos Químicos , Cor , Corantes/análise , Corantes/toxicidade , Teoria da Densidade Funcional , Metais , Estrutura Molecular , Pigmentação , Análise Espectral , Peixe-Zebra
2.
Sci Adv, v. 6, n. 14, eaaz0421, abr. 2020
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: bud-3010

RESUMO

Blue natural pigments are rare, especially among plants. However, flowering species that evolved to attract Hymenoptera pollinators are colored by blue anthocyanin-metal complexes. Plants lacking anthocyanins are pigmented by betalains but are unable to produce blue hues. By extending the p-system of betalains, we designed a photostable and metal-free blue dye named BeetBlue that did not show toxicity to human hepatic and retinal pigment epithelial cells and does not affect zebrafish embryonal development. This chiral dye can be conveniently synthesized from betalamic acid obtained from hydrolyzed red beetroot juice or by enzymatic oxidation of L-dopa. BeetBlue is blue in the solid form and in solution of acidified polar molecular solvents, including water. Its capacity to dye natural matrices makes BeetBlue the prototype of a new class of low-cost bioinspired chromophores suitable for a myriad of applications requiring a blue hue.

3.
Sci. Adv. ; 6(14): eaaz0421, 2020.
Artigo em Inglês | Sec. Est. Saúde SP, SESSP-IBPROD, Sec. Est. Saúde SP | ID: but-ib17609

RESUMO

Blue natural pigments are rare, especially among plants. However, flowering species that evolved to attract Hymenoptera pollinators are colored by blue anthocyanin-metal complexes. Plants lacking anthocyanins are pigmented by betalains but are unable to produce blue hues. By extending the p-system of betalains, we designed a photostable and metal-free blue dye named BeetBlue that did not show toxicity to human hepatic and retinal pigment epithelial cells and does not affect zebrafish embryonal development. This chiral dye can be conveniently synthesized from betalamic acid obtained from hydrolyzed red beetroot juice or by enzymatic oxidation of L-dopa. BeetBlue is blue in the solid form and in solution of acidified polar molecular solvents, including water. Its capacity to dye natural matrices makes BeetBlue the prototype of a new class of low-cost bioinspired chromophores suitable for a myriad of applications requiring a blue hue.

4.
Braz J Med Biol Res ; 52(9): e8935, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31482979

RESUMO

The scientific publication landscape is changing quickly, with an enormous increase in options and models. Articles can be published in a complex variety of journals that differ in their presentation format (online-only or in-print), editorial organizations that maintain them (commercial and/or society-based), editorial handling (academic or professional editors), editorial board composition (academic or professional), payment options to cover editorial costs (open access or pay-to-read), indexation, visibility, branding, and other aspects. Additionally, online submissions of non-revised versions of manuscripts prior to seeking publication in a peer-reviewed journal (a practice known as pre-printing) are a growing trend in biological sciences. In this changing landscape, researchers in biochemistry and molecular biology must re-think their priorities in terms of scientific output dissemination. The evaluation processes and institutional funding for scientific publications should also be revised accordingly. This article presents the results of discussions within the Department of Biochemistry, University of São Paulo, on this subject.


Assuntos
Bioquímica , Biologia Molecular , Publicações Periódicas como Assunto/estatística & dados numéricos , Editoração/tendências , Pesquisa , Brasil , Humanos , Publicações Periódicas como Assunto/normas , Publicações Periódicas como Assunto/tendências
5.
Braz. j. med. biol. res ; 52(9): e8935, 2019. graf
Artigo em Inglês | LILACS | ID: biblio-1019568

RESUMO

The scientific publication landscape is changing quickly, with an enormous increase in options and models. Articles can be published in a complex variety of journals that differ in their presentation format (online-only or in-print), editorial organizations that maintain them (commercial and/or society-based), editorial handling (academic or professional editors), editorial board composition (academic or professional), payment options to cover editorial costs (open access or pay-to-read), indexation, visibility, branding, and other aspects. Additionally, online submissions of non-revised versions of manuscripts prior to seeking publication in a peer-reviewed journal (a practice known as pre-printing) are a growing trend in biological sciences. In this changing landscape, researchers in biochemistry and molecular biology must re-think their priorities in terms of scientific output dissemination. The evaluation processes and institutional funding for scientific publications should also be revised accordingly. This article presents the results of discussions within the Department of Biochemistry, University of São Paulo, on this subject.


Assuntos
Humanos , Publicações Periódicas como Assunto/estatística & dados numéricos , Editoração/tendências , Pesquisa , Bioquímica , Biologia Molecular , Publicações Periódicas como Assunto/normas , Publicações Periódicas como Assunto/tendências , Brasil
6.
J Phys Chem B ; 112(27): 8188-97, 2008 Jul 10.
Artigo em Inglês | MEDLINE | ID: mdl-18558755

RESUMO

The anionic sugar-phosphate backbone of nucleic acids substantially contributes to their structural flexibility. To model nucleic acid structure and dynamics correctly, the potentially sampled substates of the sugar-phosphate backbone must be properly described. However, because of the complexity of the electronic distribution in the nucleic acid backbone, its representation by classical force fields is very challenging. In this work, the three-dimensional potential energy surfaces with two independent variables corresponding to rotations around the alpha and gamma backbone torsions are studied by means of high-level ab initio methods (B3LYP/6-31+G*, MP2/6-31+G*, and MP2 complete basis set limit levels). The ability of the AMBER ff99 [Wang, J. M.; Cieplak, P.; Kollman, P. A. J. Comput. Chem. 2000, 21, 1049-1074] and parmbsc0 [Perez, A.; Marchan, I.; Svozil, D.; Sponer, J.; Cheatham, T. E.; Laughten, C. A.; Orozco, M. Biophys. J. 2007, 92, 3817-3829] force fields to describe the various alpha/gamma conformations of the DNA backbone accurately is assessed by comparing the results with those of ab initio quantum chemical calculations. Two model systems differing in structural complexity were used to describe the alpha/gamma energetics. The simpler one, SPM, consisting of a sugar and methyl group linked through a phosphodiester bond was used to determine higher-order correlation effects covered by the CCSD(T) method. The second, more complex model system, SPSOM, includes two deoxyribose residues (without the bases) connected via a phosphodiester bond. It has been shown by means of a natural bond orbital analysis that the SPSOM model provides a more realistic representation of the hyperconjugation network along the C5'-O5'-P-O3'-C3' linkage. However, we have also shown that quantum mechanical investigations of this model system are nontrivial because of the complexity of the SPSOM conformational space. A comparison of the ab initio data with the ff99 potential energy surface clearly reveals an incorrect ff99 force-field description in the regions where the gamma torsion is in the trans conformation. An explanation is proposed for why the alpha/gamma flips are eliminated so successfully when the parmbsc0 force-field modification is used.


Assuntos
Desoxirribose/química , Elétrons , Modelos Moleculares , Ácidos Nucleicos/química , Fosfatos/química , Ribose/química , Conformação de Ácido Nucleico , Teoria Quântica , Software , Água/química
7.
Electromyogr Clin Neurophysiol ; 46(6): 355-63, 2006 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-17147078

RESUMO

The aim was to analyze the inteiference in a signal acquisition module (SAM) EMG1000 (Lynx--10(9) Ohms, 16 bits and range of +/-1 V), with active surface electrode (Lynx--gain 20, IRMC > 100 dB) placed over the belly of the brachial biceps of 18 healthy, sedentary volunteers, without osteomyoarticular pathologies in the upper members. Initially, the intrinsic noise of the SAM was assessed by means of a short-circuit between the simple differential and the reference electrodes, and a second stage consisted of collecting the electromyographic signal at rest of the brachial biceps muscle in 4 different procedures. (1) SAM and desktop in the electrical network (EN); (2) SAM in the battery and desktop in the EN; (3) SAM in the EN and desktop connected to the fibre optic (FO) and (4) SAM in the battery and desktop in the FO. The rest signal was collected for 10 seconds and repeated 3 times. RMS and median frequency were assessed with the software Matlab. Under conditions 1, 2 and 3 there was great interference in the signal by EN. Whereas under condition 4, the interference was eliminated. According to the results, the electrical insulation proposed was efficient in eliminating the noise, guaranteeing the quality of the acquired signal.


Assuntos
Artefatos , Eletromiografia/métodos , Músculo Esquelético/fisiologia , Processamento de Sinais Assistido por Computador/instrumentação , Adulto , Braço , Eletricidade , Eletrodos , Eletromiografia/instrumentação , Desenho de Equipamento , Feminino , Humanos
8.
Electromyogr Clin Neurophysiol ; 46(7-8): 391-9, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-17191731

RESUMO

The objective of this study was to assess the influence of different stimuli on the muscular response of 30 young sedentary male and female subjects. A conditioning module with A/D 16/32 signals of 12 bits (LYNX), with band-pass filter of 10-500 Hz and sampling frequency of 1000 Hz was used. A bipolar active surface electrode (LYNX), a load cell (MM-100 KRATOS) and a pressure cuff were also used. The volunteers were submitted to four conditions: Without stimulus (WS), auditive stimulus (AS), visual stimulus (VS), and auditive + visual stimuli (AVS). Matlab 6.5.1 software was used to process the signals for analyzing RMS and median frequency (MF), as well as muscular force (F) and cuff pressure (P). Statistical analysis consisted of the Wilcoxon and Mann-Whitney test with a critical level of 5%. As to RMS, females presented a significant increase in all types of stimuli compared to WS. As to MF there was no significant difference between the different groups for either sex. P in both sexes presented a significant increase when submitted to VS and AVS. F was higher for AVS in males and for any of the stimuli in females when compared to WS. In all the variables analyzed, males presented significantly higher values than females for all types of stimuli.


Assuntos
Estimulação Acústica , Eletromiografia/métodos , Músculo Esquelético/inervação , Estimulação Luminosa , Adolescente , Adulto , Braço , Nível de Alerta/fisiologia , Feminino , Humanos , Contração Isométrica/fisiologia , Masculino , Neurônios Motores/fisiologia , Força Muscular/fisiologia , Dinamômetro de Força Muscular , Fatores Sexuais
9.
J Gen Virol ; 87(Pt 8): 2423-2431, 2006 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-16847139

RESUMO

Phage P4 int gene encodes the integrase responsible for phage integration into and excision from the Escherichia coli chromosome. Here, the data showing that P4 int expression is regulated in a complex manner at different levels are presented. First of all, the Pint promoter is regulated negatively by both Int and Vis, the P4 excisionase. The N-terminal portion of Int appears to be sufficient for such a negative autoregulation, suggesting that the Int N terminus is implicated in DNA binding. Second, full-length transcripts covering the entire int gene could be detected only upon P4 infection, whereas in P4 lysogens only short 5'-end covering transcripts were detectable. On the other hand, transcripts covering the 5'-end of int were also very abundant upon infection. It thus appears that premature transcription termination and/or mRNA degradation play a role in Int-negative regulation both on the basal prophage transcription and upon infection. Finally, comparison between Pint-lacZ transcriptional and translational fusions suggests that Vis regulates Int expression post-transcriptionally. The findings that Vis is also an RNA-binding protein and that Int may be translated from two different start codons have implications on possible regulation models of Int expression.


Assuntos
Colífagos/genética , Proteínas de Ligação a DNA/fisiologia , Escherichia coli/virologia , Regulação Viral da Expressão Gênica , Integrases/biossíntese , Proteínas Virais/fisiologia , Fusão Gênica Artificial , Sítios de Ligação Microbiológicos , Sequência de Bases , Colífagos/enzimologia , Proteínas de Ligação a DNA/biossíntese , Proteínas de Ligação a DNA/genética , Escherichia coli/genética , Genes Reporter , Integrases/genética , Dados de Sequência Molecular , Ligação Proteica , Estrutura Terciária de Proteína , RNA Mensageiro/análise , RNA Viral/análise , beta-Galactosidase/análise , beta-Galactosidase/genética
10.
Braz. j. phys. ther. (Impr.) ; 8(1): 21-27, jan.-abr. 2004.
Artigo em Português | LILACS | ID: lil-384515

RESUMO

O objetivo deste estudo foi avaliar o conteudo de glicogenio (GLI) dos musculos soleo (S) e gastrocnemios brancos (GB) e vermelho (GV) normais e desnervados, as concentracoes plasmaticas de glicose, acidos graxos livres (AGL) e lactato, alem do peso muscular de ratos machos, submetidos a estimulacao eletrica (EE) percutanea (f=10 Hz; i=5 mA; fase= 3 ms, 20 min/dia, por 30 dias alternados) associada ou nao a metformia (MET, 1,4mg.ml-1). A glicemia e o AGL foram determinados por testes laboratoriais e o GLI, pelo metodo fenol sulfurico. Para analise estatistica foi fixado o nivel critico de 5(por cento p<0,05). A desnervacao reduz 40,91(por cento) o GLI no S,60,61(por cento) no GV e 38,77(por cento) no GB. O tratamento isolado com MET promoveu elevacao de 250(por cento)no S controle (C) e 34,61(por cento) no S desnervado (D); 184,61(por cento) no GVC e 91,30(por cento) no GVD; e 226,53(por cento) no GBC e 166,66(por cento) no GBD. Por sua vez, a EE elevou em 111,36(por cento) o GLI no SC e 103,84(por cento) no SD; 41,54(por cento) no GVC e 147,83(por cento) no GVD; 114,28(por cento) no GBC e 153,33(por cento) no GBD. O tratamento associado (MET+EE) promoveu elevacao de 279,54(por cento) no SC e 150(por cento) no SD; 184,61(por cento) no GVC e 165,22(por cento) no GVD; 285,71(por cento) no GBC e 163,33(por cento) no GBD. A desnervacao promoveu reducao de 43,73(por cento) na massa muscular do S. Observou-se que nao houve alteracoes nas concentracoes plasmaticas de glicose, AGL e lactato. O estudo mostra que tanto a EE quanto a MET mantem o perfil metabolico dos musculos analisados, no entanto, nao foram suficientes para impedir a perda de massa muscular


Assuntos
Estimulação Elétrica , Glicogênio , Metformina
11.
Minerva Pediatr ; 55(5): 447-52, 2003 Oct.
Artigo em Italiano | MEDLINE | ID: mdl-14608267

RESUMO

AIM: The aim of this paper is to determine the efficacy of a fructo-oligosaccharides (FOS)-Lactobacillus sporogenes preparation in the prevention of diarrhea due to antibiotics in childhood. METHODS: A multicentre, randomised, double-blind versus placebo study was carried out. A total of 120 children, with active infections requiring antibiotics, were enrolled in the study and treated for 10 days either in the experimental group (F) or in the placebo one (P). The results of the study were recorded from the patients' diary and from follow-up clinical examinations. RESULTS: Out of 98 evaluable patients, 71% in group F had no diarrhea versus 38% in group P. The duration of diarrhea in F and P groups was 0.7 vs 1.6 days (p=0.002), respectively. CONCLUSION: Prophylaxis with Lactobacillus sporogens, associated to FOS, significantly reduced the number of days and duration of events in children with antibiotic-induced diarrhea.


Assuntos
Antibacterianos/efeitos adversos , Diarreia/prevenção & controle , Lactobacillus , Oligossacarídeos/uso terapêutico , Probióticos , Adolescente , Criança , Pré-Escolar , Interpretação Estatística de Dados , Diarreia/induzido quimicamente , Método Duplo-Cego , Feminino , Humanos , Lactente , Masculino , Placebos
12.
J Bacteriol ; 183(23): 6801-6, 2001 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-11698368

RESUMO

The DNA region upstream of katG in Mycobacterium smegmatis was cloned and sequenced. The furA gene, highly homologous to Mycobacterium tuberculosis furA, mapped in this region. The furA-katG organization appears to be conserved among several mycobacteria. The transcription pattern of furA and katG in M. smegmatis upon oxidative stress was analyzed by Northern blotting and primer extension. Although transcription of both furA and katG was induced upon oxidative stress, transcripts covering both genes could not be identified either by Northern blotting or by reverse transcriptase PCR. Specific transcripts and 5' ends were identified for furA and katG, respectively. By cloning M. smegmatis and M. tuberculosis DNA regions upstream of a reporter gene, we demonstrated the presence of two promoters, pfurA, located immediately upstream of the furA gene, and pkatG, located within the terminal part of the furA coding sequence. Transcription from pfurA was induced upon oxidative stress. A 23-bp sequence overlapping the pfurA -35 region is highly conserved among mycobacteria and streptomycetes and might be involved in controlling pfurA activity. Transcription from a cloned pkatG, lacking the upstream pfurA region, was not induced upon oxidative stress, suggesting a cis-acting regulatory role of this region.


Assuntos
Proteínas de Bactérias/genética , Mycobacterium smegmatis/genética , Estresse Oxidativo , Peroxidases/genética , Proteínas Repressoras/genética , Transcrição Gênica , Sequência de Bases , Clonagem Molecular , Dados de Sequência Molecular , Mycobacterium smegmatis/metabolismo , Regiões Promotoras Genéticas
13.
Plasmid ; 45(1): 1-17, 2001 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-11319927

RESUMO

P4 is a natural phasmid (phage-plasmid) that exploits different modes of propagation in its host Escherichia coli. Extracellularly, P4 is a virion, with a tailed icosahedral head, which encapsidates the 11.6-kb-long double-stranded DNA genome. After infection of the E. coli host, P4 DNA can integrate into the bacterial chromosome and be maintained in a repressed state (lysogeny). Alternatively, P4 can replicate as a free DNA molecule; this leads to either the lytic cycle or the plasmid state, depending on the presence or absence of the genome of a helper phage P2 in the E. coli host. As a phage, P4 is thus a satellite of P2 phage, depending on the helper genes for all the morphogenetic functions, whereas for all its episomal functions (integration and immunity, multicopy plasmid replication) P4 is completely autonomous from the helper. Replication of P4 DNA depends on its alpha protein, a multifunctional polypeptide that exhibits primase and helicase activity and binds specifically the P4 origin. Replication starts from a unique point, ori1, and proceeds bidirectionally in a straight theta-type mode. P4 negatively regulates the plasmid copy number at several levels. An unusual mechanism of copy number control is based on protein-protein interaction: the P4-encoded Cnr protein interacts with the alpha gene product, inhibiting its replication potential. Furthermore, expression of the replication genes cnr and alpha is regulated in a complex way that involves modulation of promoter activity by positive and negative factors and multiple mechanisms of transcription elongation-termination control. Thus, the relatively small P4 genome encodes mostly regulatory functions, required for its propagation both as an episomal element and as a temperate satellite phage. Plasmids that, like P4, propagate horizontally via a specific transduction mechanism have also been found in the Archaea. The presence of P4-like prophages or cryptic prophages often associated with accessory bacterial functions attests to the contribution of satellite phages to bacterial evolution.


Assuntos
Bacteriófago T4/fisiologia , Escherichia coli/virologia , Vírus Satélites/fisiologia , Proteínas Virais , Bacteriófago T4/genética , DNA Helicases/genética , Replicação do DNA , Proteínas de Ligação a DNA/genética , Regulação Viral da Expressão Gênica , Genoma Viral , Plasmídeos/genética , RNA Nucleotidiltransferases/genética , Vírus Satélites/genética
14.
Braz. j. med. biol. res ; 33(10): 1133-40, Oct. 2000. ilus
Artigo em Inglês | LILACS | ID: lil-270216

RESUMO

This article reviews recent results of studies aiming to elucidate modes of integrating signals initiated in ACTH receptors and FGF2 receptors, within the network system of signal transduction found in Y1 adrenocortical cells. These modes of signal integration should be central to the mechanisms underlying the regulation of the G0->G1->S transition in the adrenal cell cycle. FGF2 elicits a strong mitogenic response in G0/G1-arrested Y1 adrenocortical cells, that includes a) rapid and transient activation of extracellular signal-regulated kinases-mitogen-activated protein kinases (ERK-MAPK) (2 to 10 min), b) transcription activation of c-fos, c-jun and c-myc genes (10 to 30 min), c) induction of c-Fos and c-Myc proteins by 1 h and cyclin D1 protein by 5 h, and d) onset of DNA synthesis stimulation within 8 h. ACTH, itself a weak mitogen, interacts with FGF2 in a complex manner, blocking the FGF2 mitogenic response during the early and middle G1 phase, keeping ERK-MAPK activation and c-Fos and cyclin D1 induction at maximal levels, but post-transcriptionally inhibiting c-Myc expression. c-Fos and c-Jun proteins are mediators in both the strong and the weak mitogenic responses respectively triggered by FGF2 and ACTH. Induction of c-Fos and stimulation of DNA synthesis by ACTH are independent of PKA and are inhibited by the PKC inhibitor GF109203X. In addition, ACTH is a poor activator of ERK-MAPK, but c-Fos induction and DNA synthesis stimulation by ACTH are strongly inhibited by the inhibitor of MEK1 PD98059.


Assuntos
Humanos , Animais , Córtex Suprarrenal/citologia , Receptores da Corticotropina/fisiologia , Transdução de Sinais/fisiologia , Neoplasias do Córtex Suprarrenal , Ciclo Celular/fisiologia , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteína Quinase C/metabolismo , Receptores de Fatores de Crescimento de Fibroblastos/fisiologia , Células Tumorais Cultivadas/fisiologia
15.
Braz J Med Biol Res ; 33(10): 1133-40, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11004713

RESUMO

This article reviews recent results of studies aiming to elucidate modes of integrating signals initiated in ACTH receptors and FGF2 receptors, within the network system of signal transduction found in Y1 adrenocortical cells. These modes of signal integration should be central to the mechanisms underlying the regulation of the G0-->G1-->S transition in the adrenal cell cycle. FGF2 elicits a strong mitogenic response in G0/G1-arrested Y1 adrenocortical cells, that includes a) rapid and transient activation of extracellular signal-regulated kinases-mitogen-activated protein kinases (ERK-MAPK) (2 to 10 min), b) transcription activation of c-fos, c-jun and c-myc genes (10 to 30 min), c) induction of c-Fos and c-Myc proteins by 1 h and cyclin D1 protein by 5 h, and d) onset of DNA synthesis stimulation within 8 h. ACTH, itself a weak mitogen, interacts with FGF2 in a complex manner, blocking the FGF2 mitogenic response during the early and middle G1 phase, keeping ERK-MAPK activation and c-Fos and cyclin D1 induction at maximal levels, but post-transcriptionally inhibiting c-Myc expression. c-Fos and c-Jun proteins are mediators in both the strong and the weak mitogenic responses respectively triggered by FGF2 and ACTH. Induction of c-Fos and stimulation of DNA synthesis by ACTH are independent of PKA and are inhibited by the PKC inhibitor GF109203X. In addition, ACTH is a poor activator of ERK-MAPK, but c-Fos induction and DNA synthesis stimulation by ACTH are strongly inhibited by the inhibitor of MEK1 PD98059.


Assuntos
Córtex Suprarrenal/citologia , Divisão Celular/fisiologia , Receptores da Corticotropina/fisiologia , Transdução de Sinais/fisiologia , Neoplasias do Córtex Suprarrenal , Animais , Ciclo Celular/fisiologia , Humanos , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Proteína Quinase C/metabolismo , Receptores de Fatores de Crescimento de Fibroblastos/fisiologia , Células Tumorais Cultivadas/fisiologia
16.
Endocr Res ; 26(4): 825-32, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11196459

RESUMO

In G0/G1 cell cycle arrested mouse Y1 adrenocortical tumor cells ACTH39, a weak mitogen and strong anti-mitogenic agent, blocks FGF2 mitogenic activity at G1 phase, keeping untouched ERK-MAPK activation and c-Fos protein induction. Here we report two anti-mitogenic mechanisms initiated in ACTH receptors and mediated by cAMP/PKA: a) post-transcriptional down regulation of c-Myc protein; b) dephosphorylation of AKT/PKB. In Y-1 cells the activity of the Mad/Max/Myc network of transcription factors seems to be regulated by c-Myc levels. FGF2 induces c-myc gene and stabilizes c-Myc protein by a process dependent on ERK-MAPK (PD98059 sensitive), but not on PI3K (Wortmannin resistant). ACTH39, on the other hand, causes rapid decrease in c-Myc levels induced by FGF2 in wild type Y1 cells, but not in PKA-deficient Y1 clones. The ACTH inhibition of DNA synthesis stimulated by FGF2 is reversed by transient transfection and induction of the MycER chimera (fusion of c-Myc and estrogen-receptor), suggesting that c-Myc down regulation is an efficient anti-mitogenic mechanism activated by ACTH. Y1 cells display high constitutive levels of AKT/PKB, that is dependent on elevated Ras x GTP. FGF2 up regulates Ras x GTP, PI3K and AKT/PKB. ACTH antagonizes this mitogenic effect of FGF2, promoting rapid dephosphorylation of AKT/PKB.


Assuntos
Córtex Suprarrenal/patologia , Hormônio Adrenocorticotrópico/farmacologia , Fator 2 de Crescimento de Fibroblastos/farmacologia , Fase G1/fisiologia , Proteínas Serina-Treonina Quinases , Fase de Repouso do Ciclo Celular/fisiologia , Transdução de Sinais/efeitos dos fármacos , Córtex Suprarrenal/efeitos dos fármacos , Animais , Regulação para Baixo , Camundongos , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Proteínas Proto-Oncogênicas c-myc/metabolismo , Células Tumorais Cultivadas
17.
Endocr Res ; 26(4): 911-4, 2000 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-11196470

RESUMO

Mouse Y1 adrenocortical tumor cells harbor amplified and overexpressed c-Ki-ras gene, displaying relatively high constitutive levels of Ras x GTP. Here we report that Y1 cells also constitutively display high levels of phosphorylated AKT/PKB, that are dependent on Ras x GTP and PI3K. ACTH rapidly causes dephosphorylation of AKT/PKB in a cAMP/PKA dependent maner. This ACTH inhibition of the anti-apoptic and mitogenic AKT/PKB pathway is likely to be relevant in ACTH growth inhibitory effects in Y-adrenocortical cells.


Assuntos
Córtex Suprarrenal/fisiologia , Hormônio Adrenocorticotrópico/farmacologia , Apoptose/efeitos dos fármacos , Apoptose/fisiologia , Mitógenos/fisiologia , Proteínas Serina-Treonina Quinases , Sulfonamidas , Proteínas ras/fisiologia , Córtex Suprarrenal/citologia , Androstadienos/farmacologia , Animais , Proteínas Quinases Dependentes de AMP Cíclico/fisiologia , Dexametasona/farmacologia , Inibidores Enzimáticos/farmacologia , Fator 2 de Crescimento de Fibroblastos/farmacologia , Glucocorticoides/farmacologia , Isoquinolinas/farmacologia , Camundongos , Fosfatidilinositol 3-Quinases/fisiologia , Inibidores de Fosfoinositídeo-3 Quinase , Fosforilação/efeitos dos fármacos , Proteínas Proto-Oncogênicas/metabolismo , Proteínas Proto-Oncogênicas c-akt , Proteínas Proto-Oncogênicas p21(ras)/fisiologia , Células Tumorais Cultivadas , Wortmanina , Proteínas ras/antagonistas & inibidores
18.
J Bacteriol ; 181(17): 5225-33, 1999 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-10464191

RESUMO

In phage P4, transcription of the left operon may occur from both the constitutive PLE promoter and the regulated PLL promoter, about 400 nucleotides upstream of PLE. A strong Rho-dependent termination site, timm, is located downstream of both promoters. When P4 immunity is expressed, transcription starting at PLE is efficiently terminated at timm, whereas transcription from PLL is immunity insensitive and reads through timm. We report the identification of two nested genes, kil and eta, located in the P4 left operon. The P4 kil gene, which encodes a 65-amino-acid polypeptide, is the first translated gene downstream of the PLE promoter, and its expression is controlled by P4 immunity. Overexpression of kil causes cell killing. This gene is the terminal part of a longer open reading frame, eta, which begins upstream of PLE. The eta gene is expressed when transcription starts from the PLL promoter. Three likely start codons predict a size between 197 and 199 amino acids for the Eta gene product. Both kil and eta overlap the timm site. By cloning kil upstream of a tRNA reporter gene, we demonstrated that translation of the kil region prevents premature transcription termination at timm. This suggests that P4 immunity might negatively control kil translation, thus enabling transcription termination at timm. Transcription starting from PL proceeds through timm. Mutations that create nonsense codons in eta caused premature termination of transcription starting from PLL. Suppression of the nonsense mutation restored transcription readthrough at timm. Thus, termination of transcription from PLL is prevented by translation of eta.


Assuntos
Colífagos/genética , Regulação Viral da Expressão Gênica , Biossíntese de Proteínas , Transcrição Gênica , Proteínas Virais/biossíntese , Sequência de Aminoácidos , Sequência de Bases , DNA Viral , Escherichia coli/virologia , Genes Virais , Dados de Sequência Molecular , Mutagênese , Fases de Leitura Aberta , Homologia de Sequência de Aminoácidos , Proteínas Virais/genética
19.
Endocr Res ; 24(3-4): 433-7, 1998.
Artigo em Inglês | MEDLINE | ID: mdl-9888521

RESUMO

The entire ACTH receptor (ACTH-R) cDNA was amplified by RT/PCR from mouse Y-1 adrenocortical cells, subcloned into the pMOSBlue T vector, sequenced and inserted into the pSVK3 mammalian vector to obtain pSVACTHR. Balb 3T3 fibroblasts were co-transfected with pSVACTHR plus pSV2-neo and the transfectants were selected with G418 and cloned. Genomic integration of pSVACTHR and transcription of ACTH-R cDNA were checked by Southern blot and RT/PCR respectively. Expression of active ACTH-R protein was tested by measuring cAMP production in response to ACTH. Two ACTH-R expressing transfectants (clones 03 and 07) increased cAMP accumulation in response to ACTH. They were morphologically identical to parental 3T3 cells, but required 10-20% FCS to grow. In these transfectants, ACTH induced c-FOS protein expression, but did not activate the ERK isoforms of MAP Kinase and did not stimulate DNA synthesis. Apparently, the ACTH-R in Balb 3T3 cells induces the c-fos gene by a pathway independent of cAMP/protein kinase A and ERK/MAP Kinase.


Assuntos
Hormônio Adrenocorticotrópico/farmacologia , Fibroblastos/fisiologia , Regulação da Expressão Gênica/fisiologia , Proteínas Proto-Oncogênicas c-fos/genética , Proto-Oncogenes/genética , Receptores da Corticotropina/metabolismo , Células 3T3 , 8-Bromo Monofosfato de Adenosina Cíclica/farmacologia , Adenilil Ciclases/metabolismo , Animais , Bucladesina/farmacologia , Proteínas Quinases Dependentes de Cálcio-Calmodulina/metabolismo , Linhagem Celular , DNA/biossíntese , Fibroblastos/metabolismo , Camundongos , Fosforilação/efeitos dos fármacos , Transfecção/fisiologia
20.
Hum Mol Genet ; 6(11): 1961-71, 1997 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-9302277

RESUMO

The survival motor neuron (SMN) gene is the putative disease gene for human spinal muscular atrophy (SMA), an autosomal recessive disorder characterized by progressive degeneration of lower motor neurons. Two copies of the gene, centromeric and telomeric, are present in the same 5q13 chromosomal region in humans. However, only the telomeric gene is affected in SMA. The SMN gene(s) encode(s) a novel protein of unknown function. To gain insights into the role of SMN in neurons, we have identified the SMN gene ortholog in the rat, and investigated SMN expression in the CNS of rat, monkey and humans by immunocytochemistry and in situ hybridization experiments. Antibodies against the SMN amino-terminus specifically recognized a single protein identical to the in vitro translation products of human and rat SMN cDNAs. The SMN gene transcript and product were widely but unevenly expressed throughout cerebral and spinal cord areas. The SMN protein was localized mainly in the cytoplasm of specific neuronal systems, and it was particularly expressed in lower motor neurons of newborn and adult animals. Likewise, a strong hybridization signal was detected in lamina IX of the spinal ventral horn. These results support the relevance of SMN for the motor neuron function and the pathogenetic role of the SMN gene in the neuronal degeneration associated with SMA.


Assuntos
Sistema Nervoso Central/metabolismo , Expressão Gênica , Atrofia Muscular Espinal/genética , Proteínas do Tecido Nervoso/genética , Sequência de Aminoácidos , Animais , Especificidade de Anticorpos , Sequência de Bases , Células COS , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico , DNA Complementar , Células HeLa , Humanos , Técnicas Imunoenzimáticas , Hibridização In Situ , Macaca nemestrina , Masculino , Dados de Sequência Molecular , Proteínas do Tecido Nervoso/biossíntese , Proteínas do Tecido Nervoso/imunologia , RNA Mensageiro/metabolismo , Proteínas de Ligação a RNA , Coelhos , Ratos , Proteínas do Complexo SMN , Proteína 1 de Sobrevivência do Neurônio Motor
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