Molecular Biology of Osmoregulation

Rudulier, Daniel Le; Strøm, Arne R.; Dandekar, Abhaya M.; Smith, Linda Tombras; Valentine, Raymond C.

doi:10.1126/science.224.4653.1064

Cited by 567 publications

(349 citation statements)

References 20 publications

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“…compatível no citoplasma para neutralizar os efeitos dos sais acumulados no vacúolo (Steward et al, 1974;LeRudulier et al, 1984). O acúmulo de prolina favorece também a hidratação do protoplasma alem de funcionar como reserva, especialmente para a síntese de algumas enzimas específicas (Navari-Izzo et al, 1990;Lima et al, 1997).…”

Section: Resultsunclassified

Crescimento de calos embriogênicos de milho submetidos ao estresse salino<A NAME="top"></A>

Bezerra

Willadino

Câmara

2001

Sci. agric. (Piracicaba, Braz.)

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RESUMO: A salinidade do solo é um problema muito importante em áreas irrigadas do semi-árido brasileiro, onde o milho é uma cultura de subsistência. Este trabalho teve como objetivo estudar o efeito de concentrações de NaCl sobre calos embriogênicos, da cultivar Jatinã C3 Anão, uma importante cultivar de milho no Nordeste do Brasil. A indução dos calos foi feita a partir de embriões imaturos assepticamente retirados das sementes e inoculados em meio de cultura N6 suplementado com 2 mg L -1 de 2,4-D. Os calos embriogênicos foram submetidos a diferentes concentrações de cloreto de sódio (0; 50; 100; 150 e 200 mmol L -1 de NaCl), com três repetições durante 60 dias. Os calos submetidos a 100 mmol L -1 de NaCl apresentaram aumento no conteúdo de prolina na ordem de 37% quando comparado com o nível de 50 mmol L -1 de NaCl, sugerindo um efeito positivo da acumulação deste aminoácido em resposta ao estresse salino. Por outro lado, em elevadas concentrações salinas (150 e 200 mmol L -1 ) observou-se decréscimo no crescimento dos calos, bem como redução nos teores de prolina, provavelmente em função de um aumento da fração não embriogênica dos calos. Palavras-chave: Zea mays, salinidade, embriogênese somática, prolina EMBRYOGENIC CALLUS GROWTH OF MAIZE SUBMITTED TO SALT STRESSABSTRACT: Soil salinity is a very important problem in irrigated areas of the brazilian semi-arid area, where maize is a subsistence crop. To study the effect of NaCl concentrations in embryogenic calli of Jatinã C3 Anão, an important maize cultivar of the Northest of Brazil, calli were induced using immature embryos aseptically removed from the seeds and grown on N6 medium supplemented with 2 mg L -1 of 2,4-D. To study the effect of salinity in vitro, embryogenic calli were subjected to different concentrations of sodium chloride (0; 50; 100; 150 and 200 mmol L -1 of NaCl), in three replicates, during 60 days. Calli subjected up to100 mmol L -1 NaCl showed proline concentration 37% higher than callus treated with 50 mmol L -1 NaCl. This result suggests a positive effect of proline accumulation at salt stress conditions. However, at the highest concentration tested (150-200 mmol L -1 NaCl) as lower growth and also a lower proline accumulation was observed, probably due to an increase of the non embryogenic fraction of calli.

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Section: Resultsunclassified

Crescimento de calos embriogênicos de milho submetidos ao estresse salino<A NAME="top"></A>

Bezerra

Willadino

Câmara

2001

Sci. agric. (Piracicaba, Braz.)

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“…Therefore, media and growth conditions applied to P. rosea were tested with few modifications on the strains listed in Table 1. As a rule, we had first screened media known to support biomass production of our strains (data not shown) added with 1 g l -1 agar, and then we supplemented the best medium for each strain with appropriate concentrations of sucrose and proline (the latter acting as an osmo-protectant 25 ). The addition of sucrose and proline favored adaptation to the components of the hypertonic buffer (P medium) used for the subsequent cell wall digestion and for protoplast production.…”

Section: Growth Of the Strains And Protoplast Productionmentioning

confidence: 99%

Protoplast preparation and reversion to the normal filamentous growth in antibiotic-producing uncommon actinomycetes

et al. 2010

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Protoplast preparation, regeneration and fusion represent essential tools for those poorly studied biotechnologically valuable microorganisms inapplicable with the current molecular biology protocols. The protoplast production and regeneration method developed for Planobispora rosea and using the combination of hen egg-white lysozyme (HEWL) and Streptomyces globisporus mutanolysin was applied to a set of antibiotic-producing filamentous actinomycetes belonging to the Streptosporangiaceae, Micromonosporaceae and Streptomycetaceae. 10 7 -10 9 protoplasts were obtained from 100 ml of culture, after incubation times in the digestion solution ranging from a few hours to 1 or 2 days depending on the strain. The efficiency of protoplast reversion to the normal filamentous growth varied from 0.1 to nearly 50%. Analysis of cell wall peptidoglycan in three representative strains (Nonomuraea sp. ATCC 39727, Actinoplanes teichomyceticus ATCC 31121 and Streptomyces coelicolor A3(2)) has evidenced structural variations in the glycan strand and in the peptide chain, which may account for the different response to cell digestion and protoplast regeneration treatments. Keywords: antibiotics; bacterial cell wall; glycopeptides; protoplast INTRODUCTIONThe so-called rare or uncommon actinomycetes include a group of filamentous actinomycetes other than Streptomyces spp., which are quite difficult to isolate, cultivate and genetically manipulate. 1 Members of these poorly represented and difficult-to-handle group of microorganisms produce valuable antibiotics. However, the study and the following cost-effective exploitation of uncommon actinomycetes have been slow because of the lack of genetic tools, which hamper strain and product improvement. As mobile genetic elements and conjugation systems are poorly characterized in rare actinomycetes, a crucial methodology to achieve their transformation by exogenous DNA or to recombine whole genomes arising from different cell lines (Whole Genome Shuffling-WGS) is based on protoplast manipulation and fusion. Protoplast preparation and regeneration in Streptomyces spp. were originally reported by Okanishi and co-workers. 2 The method developed for streptomycetes was then applied with uneven success to Micromonospora spp. 3 and Brevibacillus spp., 4 but it soon became clear that the protocol used later was species-or even strain-specific. In other industrially valuable actinomycetes, ad hoc techniques have been developed in some cases, 5-8 but methods endowed with a broad applicability and robustness to be applied for DNA recombination and WGS are not available. A possible explanation for the different response to protocols of protoplast

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“…Several reports have shown that osmoprotectors, such as betaine and proline, allow the bacteria to support higher concentrations of sodium chloride (Le Rudulier and Bouillard 1983;Le Rudulier et al 1984). Knochel (1990) observed a high correlation between the optimal growth temperature of several Aeromonas spp.…”

Section: -----------------------------------------------------mentioning

confidence: 99%

“…adaptation of bacterial cells to high sodium chloride concentrations has been associated with modification of the circulation of sodium ions across the membrane (Le Rudulier et al 1984). Several reports have shown that osmoprotectors, such as betaine and proline, allow the bacteria to support higher concentrations of sodium chloride (Le Rudulier and Bouillard 1983;Le Rudulier et al 1984).…”

Section: -----------------------------------------------------mentioning

confidence: 99%

Growth of Aeromonas species on increasing concentrations of sodium chloride

Delamare¹,

Costa²,

Silveira³

et al. 2000

Lett Appl Microbiol

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The growth of 16 strains of Aeromonas, representing 12 species of the genera, were examined at different salt levels (0-1·71 M NaCl). All the strains grew on media with 0·34 M NaCl, and nine on media with 0·68 M. Two strains, Aer. enteropelogenes and Aer. trota, were able to grow on media with 0·85 M and 1·02 M NaCl, respectively. Comparison of the growth curves of Aer. hydrophila ATCC7966 and Aer. trota ATCC 49657 on four concentrations of NaCl (0·08, 0·34, 0·68 and 1·02 M) confirm the high tolerance of Aer. trota, and indicate that high concentrations of salt increase the lag time and decrease the maximum growth rate. However, both strains were able to grow, slowly, in at least 0·68 M NaCl, a sodium chloride concentration currently used as food preservative.

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Molecular Biology of Osmoregulation

Cited by 567 publications

References 20 publications

Crescimento de calos embriogênicos de milho submetidos ao estresse salino<A NAME="top"></A>

Crescimento de calos embriogênicos de milho submetidos ao estresse salino<A NAME="top"></A>

Protoplast preparation and reversion to the normal filamentous growth in antibiotic-producing uncommon actinomycetes

Growth of Aeromonas species on increasing concentrations of sodium chloride

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