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2.
J Int Migr Integr ; 24(Suppl 2): 407-426, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35531269

RESUMO

When emigrant families return-migrate to their homeland, what happens to their school-age children? What challenges do these children face when they switch to a different school system and language? This paper addresses these questions in the context of family return migration to Latvia, based on 40 in-depth interviews with children, their parents and key informants - teachers, school support staff and return-migration coordinators. We find that imaginings of a smooth reintegration into a parental homeland of extended family and friends may not be realised; instead, many children, particularly those of secondary and upper primary-school age, experience the move as a rupture in their lives. School may be fraught with unrealistic expectations on all sides, not helped by poor communication between parents, teachers and support staff. The lack of fluency in the Latvian language is seen by teachers as an obstacle, rather than something to be accepted and worked with. Most teachers are unfamiliar with children from different backgrounds and origins and need training in diversity, tolerance and differentiated learning. This will become increasingly necessary in a country like Latvia, with its ongoing high rates of international migration and return. Our findings show that the educational system and children's experiences of schooling play a crucial role in returnee families' overall reintegration. This raises the importance of return preparedness for the children, including language preparation and awareness of pedagogical and curriculum differences.

3.
J Int Migr Integr ; 24(Suppl 2): 369-385, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-35789700

RESUMO

The recent geo-politicisation of return migration warrants deep consideration of the politics of return and reintegration. A focus on geopolitics prefigures the study of reintegration not just as circumstantial to the lives of migrants or the formal strategies of states but also as deeply embedded in the historical socio-cultural and political contexts where it takes place. In introducing a set of papers that explore these links from different angles and based on research from around the world, this article argues that return and reintegration constitute a qualitatively different process from immigration and integration in the receiving countries, first and foremost because the sending state-a key actor in the reintegration process-is in a position of geopolitical power marginality. Indeed, the strategies of all the stakeholders implicated in reintegration are closely linked to the geopolitics of migration governance. In these contexts, migrants' intimate, as well as pragmatic, strategies of reintegration and re-migration are an expression, as well as a trigger, of multi-scale geopolitics. There is a distinct contrast between the emphasis on borders and securitisation in high-income countries and the informality and precarity of the way that migrants have to manage their ontological security in the process of return and reintegration. Reintegration should thus be understood as a process contingent upon different and, often, incongruous legal, political and socio-economic elements, as endorsed and employed by the different stakeholders involved.

4.
J Med Entomol ; 59(2): 764-771, 2022 03 16.
Artigo em Inglês | MEDLINE | ID: mdl-35064668

RESUMO

To date, Triatoma dimidiata sensu lato [Reduviidae: Triatominae (Latreille 1811)] remains the sole vector species associated with Chagas disease transmission reported from Belize. Human infection data are limited for Belize and the disease transmission dynamics have not been thoroughly investigated, yet the likelihood of autochthonous transmission is supported by the widespread collection of infected vectors from within local households. Here, we report updated infection rates of the vector population and infestation rates for villages in north and central Belize. Overall, 275 households were enrolled in an ongoing vector surveillance program. Of the 41 insects collected, 25 were PCR positive for T. cruzi, indicating an infection rate as high as 60%. To further characterize the epidemiological risk of human-vector contact, determinants of household invasion were modeled. Local households were surveyed and characterized with respect to over 25 key factors that may be associated with household infestation by T. dimidiata s.l. While final models were not strongly predictive with respect to the risk factors that were surveyed, likely due to the low number of collection observations, the presence of domestic/peri-domestic dogs, nearby light sources, and household structure materials could be the focus of continued risk assessments. In northern Belize, this vector survey lends support to T. dimidiata s.l. inhabiting sylvatic settings as opposed to the classical paradigm of domiciliated vector populations. This designation has strong implications for the local level of human exposure risk which can help guide vector surveillance and control resources.


Assuntos
Doença de Chagas , Doenças do Cão , Triatoma , Triatominae , Trypanosoma cruzi , Animais , Belize , América Central , Doença de Chagas/epidemiologia , Cães , Insetos Vetores , Fatores de Risco
5.
Comp Migr Stud ; 8(1): 35, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33024701

RESUMO

This commentary paper starts by questioning the assumption that migration means international migration, and goes on to affirm that migration studies has indeed come of age as a coherent if highly diverse research field. Several emerging epistemic communities are identified: migration and development; gender and migration; lifestyle migration; and youth and student migrations. Finally, I argue that the role of geography in the study of migration has been under-valued.

6.
J Gerontol B Psychol Sci Soc Sci ; 74(8): 1492-1500, 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-30346616

RESUMO

OBJECTIVES: We explore and compare older adults' lived experiences and coping strategies in two postcommunist countries-Albania and Bulgaria. Wholesale youth outmigration and economic and institutional regional decline have led to decaying rural areas where older adults become "abandoned." Aging alone, as couples or widowed, they are socially marginalized and in constant search for coping mechanisms which enable them to survive. METHODS: We adopt a social-psychology theoretical framework which distinguishes between problem-focused and emotion-focused coping. Data include 28 in-depth interviews with older residents and participant observation in selected rural areas of the two countries. RESULTS: In both countries, rural social isolation is expressed as a lack of close family ties-mainly due to the removal through outmigration of children and grandchildren-and detachment from society at large. The most prevalent coping mechanism consists of practical and emotional support from non-kin ties, especially neighbors. Remittances help to resolve material needs, especially in Albania, where most rural young people migrate abroad. In both settings, a range of emotion-focused coping strategies were identified, including perceptions of decreased needs, lowered expectations about relationships, and satisfaction at the achievements of the younger generations. DISCUSSION: Similarities between research findings in Albania and Bulgaria reflect their shared political and institutional history. Although few, differences relate to a combination of contrasting migration and cultural patterns. In both settings problem- and emotion-focused adaptive strategies are overlapping, and successful aging efforts seem to be of a communal rather than an individualistic nature.


Assuntos
Adaptação Psicológica , Idoso/psicologia , Envelhecimento/psicologia , Pessoa Solteira/psicologia , Idoso de 80 Anos ou mais , Albânia , Bulgária , Família/psicologia , Feminino , Humanos , Entrevistas como Assunto , Solidão/psicologia , Masculino , Pessoa de Meia-Idade , População Rural , Pessoa Solteira/estatística & dados numéricos , Apoio Social
7.
J Vasc Interv Radiol ; 27(3): 345-53, 2016 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-26826941

RESUMO

PURPOSE: To retrospectively evaluate the safety, efficacy, and retrievability of Option inferior vena cava (IVC) filters. MATERIALS AND METHODS: All patients (N = 516; 247 women; mean age, 67.1 y ± 15.1; range, 19.5-101.6 y) who received an Option filter between August 2009 and March 2015 at a single health care system were analyzed. RESULTS: The study duration was 68 months, with median clinical follow-up of 7.1 months (range, 1 d to 61.8 mo). During follow-up, 73 of 83 patients (88.0%) underwent successful filter retrieval, 153 died (including three after successful retrieval), and 293 remained alive with filters in situ. Seventeen cases of breakthrough pulmonary embolism (PE) occurred (3.4%). Among 323 patients with direct filter imaging, there were two cases of tilt > 15°, one case of filter deformity, 16 cases of intracaval migration > 2 cm, and no cases of filter fracture. There were six cases of caval occlusion, nine cases of thrombus trapped inside the filter, and 57 cases of limb penetration on computed tomography scans or radiographs of the IVC. Retrieval failures were attributed to filter tilt or tip embedment in the caval wall (n = 4), complete IVC thrombosis (n = 3), thrombus inside the filter (n = 2), or inability to disengage filter legs (n = 1). Recurrent deep vein thrombosis occurred in 34 patients, including 32 with filters in situ and two whose filters had been removed. CONCLUSIONS: Most Option filters were left in situ for permanent indications. Rates of successful retrieval, device-related complications, and breakthrough PE were similar to those associated with other retrievable filters.


Assuntos
Implantação de Prótese/instrumentação , Embolia Pulmonar/prevenção & controle , Filtros de Veia Cava , Veia Cava Inferior , Trombose Venosa/terapia , Adulto , Idoso , Idoso de 80 Anos ou mais , Remoção de Dispositivo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Flebografia/métodos , Desenho de Prótese , Falha de Prótese , Implantação de Prótese/efeitos adversos , Implantação de Prótese/mortalidade , Embolia Pulmonar/diagnóstico por imagem , Embolia Pulmonar/mortalidade , Recidiva , Estudos Retrospectivos , Fatores de Risco , Fatores de Tempo , Tomografia Computadorizada por Raios X , Resultado do Tratamento , Filtros de Veia Cava/efeitos adversos , Veia Cava Inferior/diagnóstico por imagem , Trombose Venosa/diagnóstico por imagem , Trombose Venosa/mortalidade , Adulto Jovem
8.
Malar J ; 14: 184, 2015 Apr 29.
Artigo em Inglês | MEDLINE | ID: mdl-25925395

RESUMO

BACKGROUND: Campaigns for the continued reduction and eventual elimination of malaria may benefit from new and innovative vector control tools. One novel approach being considered uses a push-pull strategy, whereby spatial repellents are used in combination with outdoor baited traps. The desired effect is the behavioural manipulation of mosquito populations to elicit movement of vectors away from people and into traps. METHODS: Here, a prototype push-pull intervention was evaluated using an experimental hut methodology to test proof-of-principle for the strategy against two natural vector populations, Anopheles albimanus and Anopheles vestitipennis, in Belize, Central America. A Latin square study design was used to compare mosquito entry into experimental huts and outdoor traps across four different experimental conditions: 1) control, with no interventions; 2) pull, utilizing only outdoor traps; 3) push, utilizing only an indoor spatial repellent; and 4) push-pull, utilizing both interventions simultaneously. RESULTS: For An. vestitipennis, the combined use of an indoor repellent and outdoor baited traps reduced average nightly mosquito hut entry by 39% (95% CI: [0.37-0.41]) as compared to control and simultaneously increased the nightly average densities of An. vestitipennis captured in outdoor baited traps by 48% (95% CI: [0.22-0.74]), compared to when no repellent was used. Against An. albimanus, the combined push-pull treatment similarly reduced hut entry, by 54% (95% CI: [0.40-0.68]) as compared to control; however, the presence of a repellent indoors did not affect overall outdoor trap catch densities for this species. Against both anopheline species, the combined intervention did not further reduce mosquito hut entry compared to the use of repellent alone. CONCLUSIONS: The prototype intervention evaluated here clearly demonstrated that push-pull strategies have potential to reduce human-vector interactions inside homes by reducing mosquito entry, and highlighted the possibility for the strategy to simultaneously decrease human-vector interactions outside of homes by increasing baited trap collections. However, the variation in effect on different vectors demonstrates the need to characterize the underlying behavioral ecology of target mosquitoes in order to drive local optimization of the intervention.


Assuntos
Anopheles , Repelentes de Insetos , Insetos Vetores , Malária/prevenção & controle , Controle de Mosquitos/métodos , Animais , Belize , Feminino , Humanos , Malária/transmissão
9.
Malar J ; 14(184): [1-11], 2015. maps, ilus, tab, graf
Artigo em Inglês | MedCarib | ID: biblio-910961

RESUMO

BACKGROUND: Campaigns for the continued reduction and eventual elimination of malaria may benefit from new and innovative vector control tools. One novel approach being considered uses a push-pull strategy, whereby spatial repellents are used in combination with outdoor baited traps. The desired effect is the behavioural manipulation of mosquito populations to elicit movement of vectors away from people and into traps. METHODS: Here, a prototype push-pull intervention was evaluated using an experimental hut methodology to test proof-of-principle for the strategy against two natural vector populations, Anopheles albimanus and Anopheles vestitipennis in Belize, Central America. A Latin square study design was used to compare mosquito entry into experimental huts and outdoor traps across four different experimental conditions: 1) control, with no interventions; 2) pull, utilizing only outdoor traps; 3) push, utilizing only an indoor spatial repellent; and 4) push-pull, utilizing both interventions simultaneously. RESULTS: For An. vestitipennis, the combined use of an indoor repellent and outdoor baited traps reduced average nightly mosquito hut entry by 39% (95% CI: [0.37 ­ 0.41]) as compared to control and simultaneously increased the nightly average densities of An. vestitipennis captured in outdoor baited traps by 48% (95% CI: [0.22 ­ 0.74]), compared to when no repellent was used. Against An. albimanus, the combined push-pull treatment similarly reduced hut entry, by 54% (95% CI: [0.40 ­ 0.68]) as compared to control; however, the presence of a repellent indoors did not affect overall outdoor trap catch densities for this species. Against both anopheline species, the combined intervention did not further reduce mosquito hut entry compared to the use of repellent alone. CONCLUSIONS: The prototype intervention evaluated here clearly demonstrated that push-pull strategies have potential to reduce human-vector interactions inside homes by reducing mosquito entry, and highlighted the possibility for the strategy to simultaneously decrease human-vector interactions outside of homes by increasing baited trap collections. However, the variation in effect on different vectors demonstrates the need to characterize the underlying behavioral ecology of target mosquitoes in order to drive local optimization of the intervention…(AU)


Assuntos
Humanos , Masculino , Feminino , Experimentação Animal/estatística & dados numéricos , Malária/prevenção & controle , Controle de Mosquitos/métodos , Controle de Vetores de Doenças , Belize/epidemiologia
10.
Health Syst (Basingstoke) ; 3(2): 83-92, 2014 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25013721

RESUMO

Many major incidents have significant impacts on people's health, placing additional demands on health-care organisations. The main aim of this paper is to suggest a prioritised agenda for organisational and management research on emergency planning and management relevant to U.K. health care, based on a scoping study. A secondary aim is to enhance knowledge and understanding of health-care emergency planning among the wider research community, by highlighting key issues and perspectives on the subject and presenting a conceptual model. The study findings have much in common with those of previous U.S.-focused scoping reviews, and with a recent U.K.-based review, confirming the relative paucity of U.K.-based research. No individual research topic scored highly on all of the key measures identified, with communities and organisations appearing to differ about which topics are the most important. Four broad research priorities are suggested: the affected public; inter- and intra-organisational collaboration; preparing responders and their organisations; and prioritisation and decision making.

11.
J Am Mosq Control Assoc ; 30(3): 175-83, 2014 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-25843092

RESUMO

To achieve maximum success from any vector control intervention, it is critical to identify the most efficacious tools available. The principal aim of this study was to evaluate the efficacy of 2 commercially available adult mosquito traps for capturing Anopheles albimanus and An. vestitipennis, 2 important malaria vectors in northern Belize, Central America. Additionally, the impact of outdoor baited traps on mosquito entry into experimental huts was assessed. When operated outside of human-occupied experimental huts, the Centers for Disease Control and Prevention (CDC) miniature light trap, baited with human foot odors, captured significantly greater numbers of female An. albimanus per night (5.1 ± 1.9) than the Biogents Sentinel™ trap baited with BG-Lure™ (1.0 ± 0.2). The 2 trap types captured equivalent numbers of female An. vestitipennis per night, 134.3 ± 45.6 in the CDC trap and 129.6 ± 25.4 in the Sentinel trap. When compared to a matched control hut using no intervention, the use of baited CDC light traps outside an experimental hut did not impact the entry of An. vestitipennis into window interception traps, 17.1 ± 1.3 females per hour in experimental huts vs. 17.2 ± 1.4 females per hour in control huts. However, the use of outdoor baited CDC traps did significantly decrease the entry of An. albimanus into window interception traps from 3.5 ± 0.5 females per hour to 1.9 ± 0.2 females per hour. These results support existing knowledge that the underlying ecological and behavioral tendencies of different Anopheles species can influence trap efficacy. Furthermore, these findings will be used to guide trap selection for future push-pull experiments to be conducted at the study site.


Assuntos
Anopheles , Controle de Mosquitos/métodos , Mosquitos Vetores , Animais , Belize , Feminino , Malária/transmissão , Odorantes/análise , Especificidade da Espécie
12.
J Am Mosq Control Assoc ; 29(4): 319-27, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24551964

RESUMO

Anopheles darlingi is a major vector for malaria in Central and South America. Behavioral, ecological, genetic, and morphologic variability has been observed across its wide distribution. Recent studies have documented that 2 distinct genotypes exist for An. darlingi: a northern lineage (Belize, Guatemala, Colombia, Venezuela, and Panama) and a southern lineage (Amazonia and southern Brazil). In order to determine if these genotypes exhibited different behavioral traits, entrance and exit movement patterns between 2 field populations of An. darlingi that represented each genotype were evaluated using experimental huts. The Belize population exhibited bimodal entrance, with peak entry occurring between 7:00-8:00 p.m. and 5:00-6:00 a.m. and peak exiting occurring between 7:00-8:00 p.m. The Peru population exhibited unimodal entrance, with peak entry occurring between 10:00-11:00 p.m. and peak exiting occurring between 11:00-12:00 a.m. with a secondary smaller peak at 2:30 a.m. Entrance and exit behavioral patterns were significantly different between the Belize and Peru populations of An. darlingi (log-rank [Mantel-Cox] P < 0.001). Information from the present study will be used in the future to determine if there is a correlation between genotype and host-seeking behavior and can be used in the present for regional vector risk assessment.


Assuntos
Anopheles , Comportamento Animal , Insetos Vetores , Animais , Feminino , Habitação , Malária/transmissão , Peru
13.
J Am Mosq Control Assoc ; 29(4): 380-2, 2013 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-24551972

RESUMO

The first record of Aedes albopictus in northern Belize was made in Orange Walk Town, Orange Walk District, on November 3, 2011. Aedes spp. larvae were collected during a routine Ministry of Health mosquito survey and reared to adults. Upon emergence, a mixed population of Aedes aegypti (35) and Ae. albopictus (11) was observed (aegypti:albopictus = 3:1). Subsequent larval and adult surveys in Orange Walk and Corozal District, also in northern Belize, have confirmed the presence of Ae. albopictus, thereby indicating the range expansion and establishment of this nuisance biter and potential disease vector in Belize.


Assuntos
Aedes , Animais , Belize , Humanos , Insetos Vetores
14.
Journal of the American Mosquito Control Association ; 29(4): [175-183], 2013. ilus, graf, tab
Artigo em Inglês | MedCarib | ID: biblio-910888

RESUMO

To achieve maximum success from any vector control intervention, it is critical to identify the most efficacious tools available. The principal aim of this study was to evaluate the efficacy of 2 commercially available adult mosquito traps for capturing Anopheles albimanus and An. vestitipennis, 2 important malaria vectors in northern Belize, Central America. Additionally, the impact of outdoor baited traps on mosquito entry into experimental huts was assessed. When operated outside of human-occupied experimental huts, the Centers for Disease Control and Prevention (CDC) miniature light trap, baited with human foot odors, captured significantly greater numbers of female An. albimanus per night (5.1 6 1.9) than the Biogents SentinelTM trap baited with BG-LureTM (1.0 6 0.2). The 2 trap types captured equivalent numbers of female An. vestitipennis per night, 134.3 6 45.6 in the CDC trap and 129.6 6 25.4 in the Sentinel trap. When compared to a matched control hut using no intervention, the use of baited CDC light traps outside an experimental hut did not impact the entry of An. vestitipennis into window interception traps, 17.1 6 1.3 females per hour in experimental huts vs. 17.2 6 1.4 females per hour in control huts. However, the use of outdoor baited CDC traps did significantly decrease the entry of An. albimanus into window interception traps from 3.5 6 0.5 females per hour to 1.9 6 0.2 females per hour. These results support existing knowledge that the underlying ecological and behavioral tendencies of different Anopheles species can influence trap efficacy. Furthermore, these findings will be used to guide trap selection for future push­ pull experiments to be conducted at the study site...(AU)


Assuntos
Animais , Malária/epidemiologia , Controle de Mosquitos/instrumentação , Belize/epidemiologia
15.
Magn Reson Chem ; 50(9): 627-31, 2012 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-22847870

RESUMO

The normal levels and types of glycoalkaloids found in commercial varieties of potato (Solanum tuberosum) appear to present no hazard to human health. However when wild Solanum species are used in breeding endeavors, new and untested glycoalkaloids may be introduced. Recent studies of domestic crosses with a wild Solanum oplocense accession indicated that the levels of a non-indigenous glycoalkaloid appeared associated with reduced defoliation by the Colorado potato beetle. The non-indigenous glycoalkaloid was isolated from foliage of the wild S. oplocense accession and unambiguously characterized by high-resolution electrospray ionization mass spectrometry and NM analysis as the glycoalkaloid dehydrocommersonine.


Assuntos
Alcaloides de Solanáceas/química , Solanum/química , Isótopos de Carbono , Espectroscopia de Ressonância Magnética/normas , Estrutura Molecular , Folhas de Planta/química , Prótons , Padrões de Referência , Alcaloides de Solanáceas/isolamento & purificação , Espectrometria de Massas por Ionização por Electrospray
16.
Phytochemistry ; 71(17-18): 2187-9, 2010 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-21030053

RESUMO

(1)H NMR analysis established that a potential suberin intermediate isolated from potato common scab lesions contained three O-methyl groups, a phenylcoumaran-type linkage and a conjugated trans double bond. Mass spectral data determined its molecular formula as indicative of a dehydrotrimer structure formed from three feruloyltyramine units. (1)H and (13)C NMR correlation studies supported the structure as that of a grossamide unit (3) linked through its double bond to the feruloyl phenolic of a third feruloyltyramine group. Identification of the feruloyltyramine trimer (4) expands the number of cross-linked intermediates potentially involved in the suberization process and highlights the presence of a second type of inter-unit linkage available for synthesis of the poly-phenolic domains.


Assuntos
Ácidos Cumáricos/química , Ácidos Cumáricos/isolamento & purificação , Doenças das Plantas , Solanum tuberosum/química , Tiramina/análogos & derivados , Estrutura Molecular , Ressonância Magnética Nuclear Biomolecular , Tiramina/química , Tiramina/isolamento & purificação
17.
J Bacteriol ; 191(15): 4786-97, 2009 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-19465647

RESUMO

Organisms belonging to the genus Streptomyces produce numerous important secondary metabolites and undergo a sophisticated morphological differentiation program. In many instances these processes are under the control of gamma-butyrolactone (GBL) autoregulatory systems. Streptomyces acidiscabies strain 84.104 produces the secondary metabolite aromatic angucyclinone polyketide WS5995B. In order to explore the role of GBL regulatory circuitry in WS5995B production and morphogenesis in S. acidiscabies, a gene cluster encoding GBL autoregulatory signaling homologs was identified and characterized. Two GBL receptor homologs, sabR and sabS, were found flanking a GBL synthase homolog sabA. Strains carrying mutations in sabS produced elevated levels of WS5995B and displayed conditional morphological defects reminiscent of defects seen in Streptomyces bldA mutants. Notably, sabS possesses a TTA codon predicted to be recognized by tRNA(leu). sabA mutants produced higher levels of WS5995B than the wild-type strain but to a lesser extent than the levels of WS5995B seen in sabS mutants. Purified recombinant SabR and SabS were tested for their abilities to bind predicted AT-rich autoregulatory element (ARE) boxes within the sabRAS region. SabS did not bind any DNA sequences in this region, while SabR bound an ARE box in the region upstream of sabS. Quantitative reverse transcription-PCR analysis revealed higher levels of sabS transcript in sabR mutants than in the wild-type strain, suggesting that sabS expression is repressed by SabR. Based on these data, we propose that the S. acidiscabies sabRAS genes encode components of a signaling pathway which participates in the regulation of WS5995B production and morphogenesis.


Assuntos
4-Butirolactona/metabolismo , Antraquinonas/metabolismo , Proteínas de Bactérias/genética , Macrolídeos/metabolismo , Família Multigênica/fisiologia , Streptomyces/genética , Streptomyces/metabolismo , Antraquinonas/química , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/fisiologia , Códon , Regulação Bacteriana da Expressão Gênica , Macrolídeos/química , Dados de Sequência Molecular , Estrutura Molecular , Família Multigênica/genética , Mutação , Ligação Proteica , RNA de Transferência de Leucina/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Reação em Cadeia da Polimerase Via Transcriptase Reversa
18.
Phytochemistry ; 70(7): 833-41, 2009 May.
Artigo em Inglês | MEDLINE | ID: mdl-19467551

RESUMO

Thaxtomin phytotoxins, first reported in 1989, are cyclic dipeptides (2,5-diketopiperazines) formed from the condensation of 4-nitrotrytophan and phenylalanine groups. Inclusion of a 4-nitroindole moiety that is an essential requirement for their phytotoxicity makes them unique amongst microbial generated metabolites. Individual thaxtomins differ only in the presence or absence of N-methyl and hydroxyl groups and their respective substitution sites. The name "thaxtomin" was assigned to these compounds in honor of the eminent American phytopathologist Roland Thaxter who first described the nature of the microorganisms responsible for their production. The great interest in the thaxtomins derives mainly from their established roles as virulence factors in the common scab of potato disease and their apparent ability to inhibit cellulose synthesis in developing plant cells. Surveys of comparable scab-inducing organisms from potato producing regions throughout the world have confirmed the generality of the phytotoxin associated process. Descriptions of the isolation, chemical structure determination, total synthesis, biosynthesis, transformation by microorganisms and biological activity of the thaxtomins are comprehensively reviewed.


Assuntos
Indóis/síntese química , Indóis/farmacologia , Piperazinas/síntese química , Piperazinas/farmacologia , Doenças das Plantas/microbiologia , Solanum tuberosum/microbiologia , Biotransformação , Indóis/química , Estrutura Molecular , Piperazinas/química , Streptomyces/metabolismo
20.
Magn Reson Chem ; 47(3): 273-6, 2009 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-19040195

RESUMO

N-acetyl-4-nitrotryptophan methyl ester (2), N-acetyl-5-nitrotryptophan methyl ester (3), N-acetyl-6-nitrotryptophan methyl ester (4) and N-acetyl-7-nitrotryptophan methyl ester (5) were synthesized through a modified malonic ester reaction of the appropriate nitrogramine analogs followed by methylation with BF(3)-methanol. Assignments of the (1)H and (13)C NMR chemical shifts were made using a combination of (1)H-(1)H COSY, (1)H-(13)C HETCOR and (1)H-(13)C selective INEPT experiments.


Assuntos
Ésteres/química , Compostos de Nitrogênio/síntese química , Acetilação , Ésteres/síntese química , Espectroscopia de Ressonância Magnética , Estrutura Molecular , Compostos de Nitrogênio/química , Triptofano/química
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