NtWBC1, an ABC transporter gene specifically expressed in tobacco reproductive organs

To identify genes specifically or predominantly expressed in the stigmas/styles and to establish their possible function in the reproductive process of plants, a tobacco stigma/style cDNA library was constructed and differentially screened, resulting in the isolation of several cDNA clones. The molecular characterization of one of these clones is described here. After sequencing the cDNA and the isolated genomic clone, it was determined that the corresponding gene encodes a protein containing an ATP-binding cassette, characteristic of ABC transporters. This gene, designated as NtWBC1 (Nicotiana tabacum ABC transporter of the White-Brown Complex subfamily), encodes a protein that contains the typical structure of the 'half-transporters' of the White subfamily. To establish the spatial expression pattern of the NtWBC1 gene, northern blot and real-time RT-PCR analyses with total RNA from roots, stems, leaves, sepals, petals, stamens, stigmas/styles, ovaries, and seeds were performed. The result revealed a transcript of 2.5 kb present at high levels in stigmas and styles and a smaller transcript (2.3 kb) present at a lower level in stamens. NtWBC1 expression is developmentally regulated in stigmas/styles, with mRNA accumulation increasing toward anthesis. In situ hybridization experiments demonstrated that NtWBC1 is expressed in the stigmatic secretory zone and in anthers, at the stomium region and at the vascular bundle. NtWBC1 is the first ABC transporter gene with specific expression in plant reproductive organs to be identified and its expression pattern suggests important role(s) in the reproductive process.

FLORAL ANATOMY of XYRIDS (POALES): CONTRIBUTIONS TO THEIR REPRODUCTIVE BIOLOGY, TAXONOMY, and PHYLOGENY

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A tobacco cDNA reveals two different transcription patterns in vegetative and reproductive organs

In order to identify genes expressed in the pistil that may have a role in the reproduction process, we have established an expressed sequence tags project to randomly sequence clones from a Nicotiana tabacum stigma/style cDNA library. A cDNA clone (MTL-8) showing high sequence similarity to genes encoding glycine-rich RNA-binding proteins was chosen for further characterization. Based on the extensive identity of MTL-8 to the RGP-1a sequence of N. sylvestris, a primer was defined to extend the 5′ sequence of MTL-8 by RT-PCR from stigma/style RNAs. The amplification product was sequenced and it was confirmed that MTL-8 corresponds to an mRNA encoding a glycine-rich RNA-binding protein. Two transcripts of different sizes and expression patterns were identified when the MTL-8 cDNA insert was used as a probe in RNA blots. The largest is 1,100 nucleotides (nt) long and markedly predominant in ovaries. The smaller transcript, with 600 nt, is ubiquitous to the vegetative and reproductive organs analyzed (roots, stems, leaves, sepals, petals, stamens, stigmas/styles and ovaries). Plants submitted to stress (wounding, virus infection and ethylene treatment) presented an increased level of the 600-nt transcript in leaves, especially after tobacco necrosis virus infection. In contrast, the level of the 1,100-nt transcript seems to be unaffected by the stress conditions tested. Results of Southern blot experiments have suggested that MTL-8 is present in one or two copies in the tobacco genome. Our results suggest that the shorter transcript is related to stress while the larger one is a flower predominant and nonstress-inducible messenger.

Centroamérica y México: políticas de competencia a principios del siglo XXI

Incluye Bibliografía

Social Security in the United States: Overview and Outlook

Includes bibliography

The relationship between fiscal and current account balances in the Caribbean

Includes bibliography

Condiciones generales de competencia en Panamá

Incluye Bibliografía

Los mercados en el Istmo Centroamericano y México: ¿qué ha pasado con la competencia?

Incluye Bibliografía

Expenditures, investment and financing for sustainable development in Trinidad and Tobago

Includes bibliography

Profile evaluation of orthodontic professionals as for their legal actions

Objective: Evaluate the legal actions and behavior in the doctor/patient relationship, used by dental surgeons practicing orthodontics. Methods: The population sample of the present study consisted of dental surgeons, active in the field of orthodontics, and registered with Dental Press Publishing Company - Maringá/PR, Brazil, with a total sample size of 525 professionals. The research was conducted using a 17-question survey forwarded to these professionals. Results and Conclusions: The majority of participants in our study are specialized in orthodontics; 75% of professionals use some sort of contract at the office/clinic; 73.7% of professionals periodically request maintenance X-rays; a large percentage of professionals (58.9%) keep patient records on file for life. The interviewed professionals demonstrate good knowledge of the Brazilian Code of Ethics in Dentistry, especially of Chapter XIV - on Communication.

O teatro experimental do negro -: estudo da personagem negra em duas peças encenadas (1947-1951)

Pós-graduação em Artes - IA

Atividade física e lipodistrofia em portadores de HIV/AIDS submetidos à terapia anti-retroviral

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Ontogenia e anatomia do gineceu de espécies de Anthurium Schott (Araceae, Alismatales)

Pós-graduação em Ciências Biológicas (Biologia Vegetal) - IBRC

A epistemologia subjacente ao currículo e à formação de licenciandos em Ciências Biológicas

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

As formas do humor. Copi: um caso argentino

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)