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1.
BMC Med Ethics ; 21(1): 62, 2020 07 25.
Artigo em Inglês | MEDLINE | ID: mdl-32711531

RESUMO

BACKGROUND: Large-scale, centralized data repositories are playing a critical and unprecedented role in fostering innovative health research, leading to new opportunities as well as dilemmas for the medical sciences. Uncovering the reasons as to why citizens do or do not contribute to such repositories, for example, to population-based biobanks, is therefore crucial. We investigated and compared the views of existing participants and non-participants on contributing to large-scale, centralized health research data repositories with those of ex-participants regarding the decision to end their participation. This comparison could yield new insights into motives of participation and non-participation, in particular the behavioural change of withdrawal. METHODS: We conducted 36 in-depth interviews with ex-participants, participants, and non-participants of a three-generation, population-based biobank in the Netherlands. The interviews focused on the respondents' decision-making processes relating to their participation in a large-scale, centralized repository for health research data. RESULTS: The decision of participants and non-participants to contribute to the biobank was motivated by a desire to help others. Whereas participants perceived only benefits relating to their participation and were unconcerned about potential risks, non-participants and ex-participants raised concerns about the threat of large-scale, centralized public data repositories and public institutes, such as social exclusion or commercialization. Our analysis of ex-participants' perceptions suggests that intrapersonal characteristics, such as levels of trust in society, participation conceived as a social norm, and basic societal values account for differences between participants and non-participants. CONCLUSIONS: Our findings indicate the fluidity of motives centring on helping others in decisions to participate in large-scale, centralized health research data repositories. Efforts to improve participation should focus on enhancing the trustworthiness of such data repositories and developing layered strategies for communication with participants and with the public. Accordingly, personalized approaches for recruiting participants and transmitting information along with appropriate regulatory frameworks are required, which have important implications for current data management and informed consent procedures.


Assuntos
Bancos de Espécimes Biológicos , Motivação , Humanos , Consentimento Livre e Esclarecido , Países Baixos , Confiança
2.
J Intellect Disabil Res ; 59(10): 970-9, 2015 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-26190561

RESUMO

BACKGROUND: Various studies have found that direct support professionals (DSPs) play an important role in determining the degree to which people with intellectual disabilities (ID) are included in society. However, less research has been conducted on the psychological processes that may influence the behavioural intentions of DSPs to actually engage with and invest effort in supporting their clients' inclusion. Five possible psychological variables are identified in the literature: attitudes, social norms, experienced competencies, identity and meta-evaluation. In our research, we tested whether these processes influence the (intended) efforts DSPs make to facilitate their clients' inclusion. METHOD: A structured questionnaire was sent to 927 DSPs working in one of three different locations (an ordinary non-segregated setting, a reversed non-segregated setting and a residential facility). Of these, 336 DSPs completed the questionnaire. RESULTS: Several variables revealed differences between the three locations, specifically in efforts to facilitate inclusion, attitudes, social norms, experienced competencies and professional identity. Looking at the overall means, we found (relatively) high scores for the experienced competencies, role identity and meta-evaluation. In contrast, the means were relatively negative regarding the DSPs' attitudes to inclusion and their assumed social norms. CONCLUSIONS: Direct support professionals' efforts to facilitate inclusion depend on their attitude towards inclusion, the experienced competencies, their role identity, the DSPs' meta-evaluation and, indirectly through attitudes, also on the assumed social norms of the relevant stakeholders. Organizations responsible for supporting people with ID and which may want their DSPs to make greater efforts to facilitate inclusion should pay attention to these psychological variables.


Assuntos
Atitude do Pessoal de Saúde , Deficiência Intelectual/reabilitação , Distância Psicológica , Adulto , Humanos
3.
Artigo em Alemão | MEDLINE | ID: mdl-23884528

RESUMO

A central objective of this study was to estimate the potential workforce for the elderly care sector in Germany and to compare it with the predicted demand for nurses in 2030. The authors describe the opportunities and obstacles in recruiting skilled professionals from EU member states and from countries outside the EU. Different scenarios of how to raise labor input are discussed so as to determine the domestic potential until 2030 in Germany. The results show that only by assuming unrealistic conditions, e. g., expectations of a high full-time working quota or far more working women, can the domestic potential meet the predicted future demands. Therefore, Germany's chances of attracting skilled foreign workers were assessed by analyzing wage differentials, unemployment probabilities, demographic developments, and professional and cultural aspects between the countries. A major finding study is that the German labor market cannot provide enough nursing care professionals for the elderly care sector by 2030. Secondly, most of the other EU member states are facing similar challenges, at least in the long run. Therefore, it is recommendable to intensify collaboration with populous Asian countries in the future.


Assuntos
Emigrantes e Imigrantes/estatística & dados numéricos , Previsões , Transição Epidemiológica , Assistência de Longa Duração , Cuidados de Enfermagem , Enfermagem , Alemanha , Assistência de Longa Duração/estatística & dados numéricos , Assistência de Longa Duração/tendências , Avaliação das Necessidades , Enfermagem/estatística & dados numéricos , Enfermagem/tendências , Cuidados de Enfermagem/estatística & dados numéricos , Cuidados de Enfermagem/tendências , Recursos Humanos
4.
Neth Heart J ; 16(6): 197-200, 2008 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-18665204

RESUMO

BACKGROUND: In patients with hypertension noncompliance with drug treatment is between 15 to 54%, and has been recognised as a relevant contributor to the burden of cardiovascular morbidity. Up to 92% of patients experience unpleasant symptoms with their condition and, particularly in these patients, the symptoms experienced may enhance compliance. OBJECTIVE: To simultaneously assess the effects of physical, social and psychological factors on noncompliance. METHODS: Patients with mild hypertension despite drug treatment, from the departments of cardiology and internal medicine, were requested to answer a self-administered questionnaire addressing the presence of physical symptoms as well as psychosocial factors. The questionnaire was based on previously used test batteries and consisted of two lists of physical complaints and four lists addressing the four domains of planned behaviour regarding medical non-adherence according to Baron and Byrne. These domains mainly assess psychosocial factors. Each list consisted of three or more items and each item was scored on fiveto seven-point scales. Mean scores were used for assessment. The lists were also separately assessed for internal consistency and reliability using Cronbach's alphas. One-way analysis of variance and multivariate analysis of variance (MANOVA) with compliance as outcome variable and the physical, social and psychological variables as indicator variables were used for data analysis. MANOVA was adjusted for multiple testing. RESULTS: Many patients experienced physical symptoms due to hypertension, such as tiredness (31%), hot flushes (28%), headache (24%), reduced daily life energy (23%), palpitations (22%), with 95% confidence intervals between 16 to 38%. Scores for physical symptoms and social factors did not differ between self-reported adherers (n=165) and nonadherers (n=11). However, the score for psychological factors was significantly larger in the adherers than in the non-adherers, 5.05 versus 3.06, p<0.018. The MANOVA showed a significant overall difference between the adherers and non-adherers in the data at p<0.012, which was mainly due to the score for psychological factors. Conclusion. The effect of physical symptoms on non-compliance in mildly hypertensive patients is negligible. So is the effect of social factors. Psychological factors such as lacking a sense of guilt, regret and shame are major determinants of non-compliance. Physicians may play an educational role in improving their patients' compliance by addressing these determinants. We should add that the conclusions should be made with reservations, given the small number of non-adherers in our sample. (Neth Heart J 2008;16:197-200.).

5.
Biochimie ; 84(8): 705-11, 2002 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-12457558

RESUMO

The relationship between tRNA structure and function has been widely investigated by site-directed mutagenesis. This method has been a very useful tool to reveal the critical bases in tRNAs that are important for recognition and aminoacylation, but has been limited by the large number of possible base combinations in tRNA molecules. We have devised a new method that uses tRNA knockout cells for selection of functional tRNAs from a mutant tRNA gene library to overcome this limitation. To explore the mechanism of tRNA(Ala) recognition, the bases of the acceptor-stem region were randomized and active mutants were selected in a tRNA(Ala) knockout strain. Mutants of tRNA(Ala) having diverse sequence combinations in the acceptor-stem region and a broad range of functional activity to support knockout cell growth were isolated. The mutant tRNAs selected by the method included molecules containing novel base substitutions as well as extensively altered base combinations that would not be readily generated by rationally designed site-directed mutagenesis. Our results emphasize the importance of the acceptor stem as a structural unit in which some nucleotides may carry more weight than others, but in summation every nucleotide contributes to the interaction with the enzyme.


Assuntos
Escherichia coli/genética , RNA de Transferência de Alanina/genética , RNA de Transferência de Alanina/isolamento & purificação , Aminoacil-tRNA Sintetases/metabolismo , Sequência de Bases , Clonagem Molecular , Escherichia coli/citologia , Escherichia coli/metabolismo , Biblioteca Gênica , Modelos Estruturais , Dados de Sequência Molecular , Mutagênese Sítio-Dirigida , Conformação de Ácido Nucleico , Oligorribonucleotídeos/síntese química , Oligorribonucleotídeos/metabolismo , Plasmídeos/genética , RNA de Transferência de Alanina/metabolismo , Especificidade por Substrato
6.
FEMS Microbiol Lett ; 175(2): 281-9, 1999 Jun 15.
Artigo em Inglês | MEDLINE | ID: mdl-10386380

RESUMO

Listeria monocytogenes is a facultative intracellular pathogen responsible for both invasive and non-invasive food-borne illness in animals and humans. In this study, macrorestriction analysis following pulsed-field gel electrophoresis was used to show that Listeria monocytogenes serovar 1/2a strain EGD has a single chromosome containing eight NotI fragments of 1100, 850, 365, 320, 275, 40, 30 and 20 kb in size and 11 AscI fragments of 860, 470, 410, 360, 320, 250, 110, 80, 50, 30 and 20 kb. The total genome therefore comprises 3000 +/- 50 kb. The creation of a physical and genetic map of the Listeria genome was achieved by generating NotI linking clones and their use in subsequent hybridisation analysis. Using isogenic mutants harbouring additional artificial NotI restriction sites, we were able to precisely map the positions of all currently known virulence genes on the chromosome.


Assuntos
Mapeamento Cromossômico , Cromossomos Bacterianos/genética , Listeria monocytogenes/genética , Eletroforese em Gel de Campo Pulsado , Genes Bacterianos , Listeria monocytogenes/classificação , Mapeamento Físico do Cromossomo , Mapeamento por Restrição , Sorotipagem , Virulência/genética
7.
J Antibiot (Tokyo) ; 41(5): 624-37, 1988 May.
Artigo em Inglês | MEDLINE | ID: mdl-3384750

RESUMO

Antibiotic nonproducing variants of Streptomyces lasaliensis NRRL 3382R, which makes the polyether antibiotic lasalocid A (Las) and the quinoxaline antibiotic echinomycin (Ech), arose at a frequency of 3-11% after treatment with three different mutagens or regeneration of protoplasts compared with a spontaneous frequency of less than 0.1%. Cosynthesis of lasalocid A was not observed upon testing a large number of Las- mutants in different pair-wise combinations, nor did these mutants accumulate probable intermediates of lasalocid A biosynthesis. These results suggest that loss of the las genes or their expression is induced at a high frequency by mutagenic treatments. In fusions of protoplasts of a strain with the las+ ech+ spo+ nic-1 rif-3 markers with strains bearing the Las- LasS Ech- Bld- (or spo+) str-1 markers, Las+ Ech+ Spo+ StrR progeny were produced at a 61-89% frequency compared with a 1-9% frequency of StrR antibiotic producing progeny with the nic-1 or rif-3 genotypes. The more frequent restoration of antibiotic production than prototrophy or rifampicin sensitivity indicates that these antibiotic characters did not behave as normal chromosomal markers. Therefore the genetic instability might be due to the involvement of a plasmid in antibiotic production. The apparent lack of infectious transfer of the Las+ character to Las- parents in conjugal matings between the few strains tested and no correlation between the presence of a large plasmid, pKSL, and lasalocid A production in several strains of S. lasaliensis do not favor the latter hypothesis, but they do not conclusively disprove it. Consequently, we suggest that a plasmid or another mobile genetic element is controlling antibiotic production in S. lasaliensis.


Assuntos
Equinomicina/biossíntese , Lasalocida/biossíntese , Quinoxalinas/biossíntese , Streptomyces/genética , 4-Butirolactona/análogos & derivados , Conjugação Genética , Genes , Genes Bacterianos , Substâncias de Crescimento/fisiologia , Lasalocida/genética , Mutação , Plasmídeos , Protoplastos , Recombinação Genética , Streptomyces/metabolismo
10.
Skin Pharmacol Physiol ; 19(3): 140-6, 2006.
Artigo em Inglês | MEDLINE | ID: mdl-16612141

RESUMO

Bacterial colonisation of wounds may delay wound healing. Modern silver-containing dressings are antimicrobial, yet cellular toxicity is a serious side-effect. We provide data for a newly formulated silver-containing ointment dressing, Atrauman Ag, for antimicrobial activity and cytotoxicity. Atrauman Ag effectively killed a panel of commensal skin as well as pathogenic bacterial strains while cytotoxicity for HaCaT keratinocytes was only around 10%. With these favourable in vitro tests, Atrauman Ag was analysed in 86 patients with traumatic and non-healing wounds of different aetiologies. The wound state was evaluated for 3 subsequent dressing changes. The slough score was reduced from 59.2 to 35.8%, granulation tissue increased from 27 to 40% and epithelialisation went up from 12.1 to 24%. We conclude that Atrauman Ag has a superior profile of antimicrobial activity over cellular toxicity and the low silver ion release rate may prevent interference with wound-healing mechanisms.


Assuntos
Antibacterianos/uso terapêutico , Curativos Oclusivos , Prata/administração & dosagem , Cicatrização/efeitos dos fármacos , Idoso , Bactérias/efeitos dos fármacos , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Feminino , Humanos , Masculino , Testes de Sensibilidade Microbiana , Pomadas/uso terapêutico , Pomadas/toxicidade , Prata/uso terapêutico , Prata/toxicidade
11.
J Biol Chem ; 258(3): 1610-3, 1983 Feb 10.
Artigo em Inglês | MEDLINE | ID: mdl-6822525

RESUMO

The naphthoquinones lapachol and dichloroallyl lawsone readily undergo oxidative ring fission when incubated with several fungi and streptomycetes. Penicillium notatum was employed to produce the ring fission product of dichloroallyl lawsone which was isolated and characterized by spectral analyses and chemical synthesis. The mechanism of oxidative ring fission of lapachol was studied by growing P. notatum cultures in an 18O2 atmosphere. Mass spectral analysis of the isolated and labeled metabolite indicates that ring fission occurs via a monooxygenase pathway most probably involving an epoxide intermediate.


Assuntos
Antineoplásicos Fitogênicos/metabolismo , Antineoplásicos/metabolismo , Naftoquinonas/metabolismo , Penicillium/metabolismo , Espectrometria de Massas , Oxirredução , Especificidade da Espécie
12.
Appl Environ Microbiol ; 38(2): 311-3, 1979 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-574750

RESUMO

Microbial transformation of lapachol, a naturally occurring naphthoquinone, was carried out by Curvularia lunata (NRRL 2178). The fungus brings about oxidative cyclization of the substrate to dehydro-alpha-lapachone, which was isolated and characterized by nuclear magnetic resonance and mass spectral analyses; its structure was verified by chemical synthesis. The metabolite is a naturally occurring chromene possessing antibacterial and antitumor activities.


Assuntos
Antineoplásicos Fitogênicos/metabolismo , Fungos Mitospóricos/metabolismo , Naftoquinonas/metabolismo , Biotransformação , Fenômenos Químicos , Química
13.
Appl Environ Microbiol ; 35(3): 554-7, 1978 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-637549

RESUMO

The naphthoquinone lapachol (1) is readily metabolized by several fungi and streptomycetes. Preparative-scale fermentations with Penicillium notatum (UI 1602) provided a major polar metabolite (4), which was isolated and identified as an intermediate of the Hooker oxidation. The metabolite was synthesized by reacting lapachol with hydrogen peroxide under alkaline conditions.


Assuntos
Antineoplásicos Fitogênicos/metabolismo , Naftoquinonas/metabolismo , Penicillium/metabolismo , Bactérias/metabolismo , Fenômenos Químicos , Química , Fermentação , Fungos/metabolismo , Oxirredução , Especificidade da Espécie
14.
J Bacteriol ; 177(5): 1216-24, 1995 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-7868594

RESUMO

Sequence analysis of the dnrR2 locus from the cluster of daunorubicin biosynthesis genes in Streptomyces peucetius ATCC 29050 has revealed the presence of two divergently transcribed open reading frames, dnrN and dnrO. The dnrN gene appears to encode a response regulator protein on the basis of conservation of the deduced amino acid sequence relative to those of known response regulators and the properties of the dnrN::aphII mutant. Surprisingly, amino acid substitutions (glutamate and asparagine) at the putative site of phosphorylation (aspartate 55) resulted in a reduction rather than a complete loss of DnrN activity. The deduced DnrO protein was found to be similar to the Streptomyces glaucescens tetracenomycin C resistance gene repressor (TcmR) and to two Escherichia coli repressors, the biotin operon repressor (BirA) and the tetracycline resistance gene repressor (TetR). The dnrN::aphII mutation was suppressed by introduction of the dnrI gene on a plasmid. Since the introduction of dnrN failed to restore antibiotic production to a dnrI::aphII mutant, these data suggest the presence of a regulatory cascade in which dnrN activates the transcription of dnrI, which in turn activates transcription of the daunorubicin biosynthesis genes.


Assuntos
Proteínas de Ligação a DNA , Daunorrubicina/biossíntese , Regulação Bacteriana da Expressão Gênica , Genes Bacterianos/genética , Streptomyces/genética , Fatores de Transcrição , Sequência de Aminoácidos , Antraciclinas , Antibióticos Antineoplásicos/biossíntese , Proteínas de Bactérias/genética , Sequência de Bases , Genes Reguladores/genética , Modelos Genéticos , Dados de Sequência Molecular , Mutagênese Insercional , Proteínas Repressoras/genética , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos
15.
J Bacteriol ; 167(3): 893-904, 1986 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-3017918

RESUMO

Serospecific antigens isolated by EDTA extraction from four serogroups of Legionella pneumophila were analyzed for their chemical composition, molecular heterogeneity by sodium dodecyl sulfate-polyacrylamide gel electrophoresis, and immunological properties. The antigens were shown to be lipopolysaccharides and to differ from the lipopolysaccharides of other gram-negative bacteria. The serospecific antigens contained rhamnose, mannose, glucosamine, and two unidentified sugars together with 2-keto-3-deoxyoctonate, phosphate, and fatty acids. The fatty acid composition was predominantly branched-chain acids with smaller amounts of 3-hydroxymyristic acid. The antigens contain periodate-sensitive groups; mannosyl residues were completely cleaved by periodate oxidation. Hydrolysis of the total lipopolysaccharide by acetic acid resulted in the separation of a lipid A-like material that cross-reacted with the antiserum to lipid A from Salmonella minnesota but did not comigrate with it on sodium dodecyl sulfate gels. None of the four antigens contained heptose. All of the antigen preparations showed endotoxicity when tested by the Limulus amebocyte lysate assay. The results of this study indicate that the serogroup-specific antigens of L. pneumophila are lipopolysaccharides containing an unusual lipid A and core structure and different from those of other gram-negative bacteria.


Assuntos
Antígenos de Bactérias/imunologia , Legionella/imunologia , Lipopolissacarídeos/imunologia , Antígenos de Bactérias/isolamento & purificação , Carboidratos/análise , Eletroforese em Gel de Poliacrilamida , Hidrólise , Legionella/análise , Legionella/classificação , Lipopolissacarídeos/isolamento & purificação , Ácido Periódico , Pronase
16.
Antonie Van Leeuwenhoek ; 64(2): 165-76, 1993.
Artigo em Inglês | MEDLINE | ID: mdl-8092857

RESUMO

The genetic control of polyketide metabolite biosynthesis in Streptomyces sp. producing actinorhodin, daunorubicin, erythromycin, spiramycin, tetracenomycin and tylosin is reviewed. Several examples of positively-acting transcriptional regulators of polyketide metabolism are known, including some two-component sensor kinase-response regulator systems. Translational and posttranslational control mechanisms are only briefly mentioned since very little is known about either of these processes. Examples of how enzyme levels and substrate supply affect polyketide metabolism also are discussed.


Assuntos
Antibacterianos/biossíntese , Proteínas de Bactérias/biossíntese , Furanos/síntese química , Lactonas/síntese química , Streptomyces/metabolismo , Sequência de Aminoácidos , Sequência Consenso , Daunorrubicina/biossíntese , Genes Bacterianos , Dados de Sequência Molecular , Família Multigênica , Óperon , Mapeamento por Restrição , Homologia de Sequência de Aminoácidos , Streptomyces/genética
17.
J Bacteriol ; 177(22): 6688-92, 1995 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-7592454

RESUMO

The dnrQS genes from the daunorubicin producer Streptomyces peucetius were characterized by DNA sequencing, complementation analysis, and gene disruption. The dnrQ gene is required for daunosamine biosynthesis, and dnrS appears to encode a glycosyltransferase for the addition of the 2,3,6-trideoxy-3-aminohexose, daunosamine, to epsilon-rhodomycinone.


Assuntos
Proteínas de Bactérias/genética , Daunorrubicina/biossíntese , Genes Bacterianos/genética , Glicosiltransferases , Hexosaminas/biossíntese , Streptomyces/genética , Sequência de Aminoácidos , Antraciclinas/metabolismo , Sequência de Bases , Clonagem Molecular , Sistema Enzimático do Citocromo P-450 , Teste de Complementação Genética , Hexosaminas/metabolismo , Modelos Químicos , Dados de Sequência Molecular , Mutagênese Insercional , Análise de Sequência de DNA , Homologia de Sequência de Aminoácidos , Streptomyces/enzimologia
18.
J Bacteriol ; 174(1): 144-54, 1992 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-1729206

RESUMO

Two DNA segments, dnrR1 and dnrR2, from the Streptomyces peucetius ATCC 29050 genome were identified by their ability to stimulate secondary metabolite production and resistance. When introduced into the wild-type ATCC 29050 strain, the 2.0-kb dnrR1 segment caused a 10-fold overproduction of epsilon-rhodomycinone, a key intermediate of daunorubicin biosynthesis, whereas the 1.9-kb dnrR2 segment increased production of both epsilon-rhodomycinone and daunorubicin 10- and 2-fold, respectively. In addition, the dnrR2 segment restored high-level daunorubicin resistance to strain H6101, a daunorubicin-sensitive mutant of S. peucetius subsp. caesius ATCC 27952. Analysis of the sequence of the dnrR1 fragment revealed the presence of two closely situated open reading frames, dnrI and dnrJ, whose deduced products exhibit high similarity to the products of several other Streptomyces genes that have been implicated in the regulation of secondary metabolism. Insertional inactivation of dnrI in the ATCC 29050 strain with the Tn5 kanamycin resistance gene abolished epsilon-rhodomycinone and daunorubicin production and markedly decreased resistance to daunorubicin. Sequence comparison between the products of dnrIJ and the products of the Streptomyces coelicolor actII-orf4, afsR, and redD-orf1 genes and of the Streptomyces griseus strS, the Saccharopolyspora erythraea eryC1, and the Bacillus stearothermophilus degT genes reveals two families of putative regulatory genes. The members of the DegT, DnrJ, EryC1, and StrS family exhibit some of the features characteristic of the protein kinase (sensor) component of two-component regulatory systems from other bacteria (even though none of the sequences of these four proteins show a significant overall or regional similarity to such protein kinases) and have a consensus helix-turn-helix motif typical of DNA binding proteins. A helix-turn-helix motif is also present in two of the proteins of the other family, AfsR and RedD-Orf1. Both sets of Streptomyces proteins are likely to be trans-acting factors involved in regulating secondary metabolism.


Assuntos
Antibióticos Antineoplásicos/biossíntese , Daunorrubicina/biossíntese , Streptomyces/metabolismo , Sequência de Aminoácidos , Antraciclinas , Antibióticos Antineoplásicos/análise , Sequência de Bases , Daunorrubicina/análise , Resistência Microbiana a Medicamentos , Expressão Gênica , Dados de Sequência Molecular , Mutagênese Insercional , Conformação Proteica , Mapeamento por Restrição , Homologia de Sequência do Ácido Nucleico , Streptomyces/genética , Transformação Genética
19.
J Bacteriol ; 179(13): 4446-50, 1997 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-9209071

RESUMO

Characterization of the dnmZ, dnmU, and dnmV genes from the daunorubicin-producer Streptomyces peucetius by DNA sequence analysis indicated that these genes encode a protein of unknown function plus a putative thymidine diphospho-4-keto-6-deoxyglucose-3(5)-epimerase and thymidine diphospho-4-ketodeoxyhexulose reductase, respectively. Inactivation of each of the three genes by gene disruption and replacement in the wild-type strain demonstrated that all of them are required for daunosamine biosynthesis.


Assuntos
Proteínas de Bactérias , Desidrogenases de Carboidrato/genética , Carboidratos Epimerases/genética , Daunorrubicina/biossíntese , Genes Bacterianos , Complexos Multienzimáticos/genética , Família Multigênica , Streptomyces/enzimologia , Sequência de Aminoácidos , Sequência de Bases , Clonagem Molecular , Dados de Sequência Molecular , Análise de Sequência de DNA , Streptomyces/genética
20.
J Bacteriol ; 172(6): 3427-34, 1990 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-2345153

RESUMO

Genes for the biosynthesis of daunorubicin (daunomycin) and doxorubicin (adriamycin), important antitumor drugs, were cloned from Streptomyces peucetius (the daunorubicin producer) and S. peucetius subsp. caesius (the doxorubicin producer) by use of the actI/tcmIa and actIII polyketide synthase gene probes. Restriction mapping and Southern analysis of the DNA cloned in a cosmid vector established that the DNA represented three nonoverlapping regions of the S. peucetius subsp. caesius genome. These three regions plus an additional one that hybridized to the same probes are present in the S. peucetius genome, as reported previously (K. J. Stutzman-Engwall and C. R. Hutchinson, Proc. Natl. Acad. Sci. USA 86:3135-3139, 1989). Functional analysis of representative clones from some of these regions in S. lividans, S. peucetius ATCC 29050, S. peucetius subsp. caesius ATCC 27952, and two of its blocked mutants (strains H6101 and H6125) showed that many of the antibiotic production genes reside in the region of DNA represented by the group IV clones. This conclusion is based on the production of epsilon-rhodomycinone, a key intermediate of the daunorubicin pathway, in certain S. lividans transformants and on the apparent complementation of mutations that block daunorubicin biosynthesis in strains H6101 and H6125. Some of the transformants of strains 29050, 27952, and H6125 exhibited substantial overproduction of epsilon-rhodomycinone and daunorubicin.


Assuntos
Clonagem Molecular , Daunorrubicina/biossíntese , Expressão Gênica , Genes Bacterianos , Streptomyces/genética , Antraciclinas , Antibióticos Antineoplásicos/biossíntese , Teste de Complementação Genética , Mutação , Streptomyces/metabolismo
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