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1.
J Exp Zool A Comp Exp Biol ; 305(6): 459-71, 2006 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-16489556

RESUMEN

Hatching of embryos in the estuarine crab Sesarma haematocheir is highly synchronized with nocturnal high tide and completes within 1 hr among all embryos incubated by the female. This highly synchronized hatching is induced by a "Hatching-Program Inducing Factor (HPIF)" released from the female. To further define the cues involved in synchronized hatching, experiments were designed to characterize this factor and to determine possible sites of release and temporal release patterns using strategies involving isolation of egg masses, perfusion, and ablation experiments on fully developed embryos that had not yet entered the hatching program. Embryo transplantations indicate that not only HPIF may be released from the branchial chamber, but that it is extraordinarily unstable, and loses activity within 15 min, which frustrates further attempts at characterization. Nevertheless, with regard to temporal release patterns, it was established that HPIF activity was detected during short periods over three consecutive nights prior to release of larvae. This activity did not explain the gated response of embryo release in this crab, which might correspond with circatidal larval release events in the field.


Asunto(s)
Braquiuros/embriología , Braquiuros/fisiología , Embrión no Mamífero/fisiología , Oviparidad/fisiología , Animales , Braquiuros/anatomía & histología , Braquiuros/crecimiento & desarrollo , Ecosistema , Femenino , Factores de Tiempo , Movimientos del Agua
2.
J Agric Food Chem ; 53(25): 9800-4, 2005 Dec 14.
Artículo en Inglés | MEDLINE | ID: mdl-16332134

RESUMEN

Three porphyran preparations with high emulsifying ability and varying molecular mass, 3,6-anhydrogalactose content, and sulfate content without any protenaceous component were prepared from dried nori processed from Porphyra yezoensis, a red alga. Each of these preparations was applied to demonstrate adsorption or binding to the surface of oil droplets. The decrease in porphyran concentration of the aqueous phase of O/W emulsions prepared with porphyran and with toluidine blue (TB)-porphyran complex formed by adding TB to the O/W emulsions indicated ready adsorption to the surface of oil droplets. The decrease in zeta-potential of the O/W emulsions suggested that the sulfate groups of the adsorbed porphyran were oriented toward the external aqueous phase. A biomolecular interaction analysis exhibited rapid binding of porphyran to C16-alkane, probably through 3,6-anhydrogalactose. Porphyran-coated liposomes were tolerant to digestion with phospholipase D. The increased molecular weight of the porphyran preparations had an increased effect on these characteristics. The results of this study demonstrate that the emulsifying ability of porphyran is derived from the adequate adsorption to the surface of oil droplets and that porphyran could be effectively applied to stabilize liposomes.


Asunto(s)
Liposomas/química , Sefarosa/análogos & derivados , Adsorción , Fenómenos Químicos , Química Física , Estabilidad de Medicamentos , Emulsiones/química , Interacciones Hidrofóbicas e Hidrofílicas , Fosfolipasa D/farmacología , Porphyra/química , Sefarosa/administración & dosificación , Sefarosa/análisis , Sefarosa/química
3.
Appl Microbiol Biotechnol ; 66(3): 243-8, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15300418

RESUMEN

Five mutants were obtained, Y11, Y135, Y164, Y180 and Y61, capable of accumulating higher amounts of arachidonic acid (AA) than Mortierella alpina 1S-4, an industrial strain for the production of AA-rich triacylglycerol (TG). This is thought to be due to low or no activity of n-3 desaturation with conversion of AA to eicosapentaenoic acid, which functions at a cultural temperature below 20 degrees C. In small-scale cultivation under optimum conditions, Y11 and Y61 respectively accumulated 4.97 mg/ml and 4.11 mg/ml of AA, using a high concentration of glucose at 20 degrees C, compared with 3.74 mg/ml for M. alpina 1S-4. In a 5-1 jar fermentor, the AA content in Y11 and Y61 kept increasing during cultivation, with consumption of the glucose in the medium; and this reached 1.48 mg/ml and 1.77 mg/ml (118 mg/g, 120 mg/g of dry mycelia) at day 10, respectively, compared with 0.95 mg/ml (86 mg/g of dry mycelia) for M. alpina 1S-4. From the results of lipid analysis, the TG contents of Y11 and Y61 in the major lipids were significantly higher than that of M. alpina 1S-4; and the AA percentages in TG of Y11 and Y61 were also higher. Both Y11 and Y61 are potential producers of TG rich in AA.


Asunto(s)
Ácidos Araquidónicos/biosíntesis , Ácido Graso Desaturasas/fisiología , Mortierella/metabolismo , Glucosa/metabolismo , Mortierella/crecimiento & desarrollo , Mutación , Temperatura , Triglicéridos/biosíntesis
4.
J Morphol ; 259(1): 55-68, 2004 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-14666525

RESUMEN

A pair of rosette glands (one of the tegumental glands in crustaceans) is present at the root of the dorsal spine of the thorax in mature embryos of the estuarine crab Sesarma haematocheir. Each rosette gland is spherical, 45-50 microm in diameter. This gland consists of three types of cells: 18-20 secretory cells, one central cell, and one canal cell. The secretory cells are further classified into two types on the basis of the morphology of secretory granules. There are 17-19 a cells, and only one b cell per rosette gland. An a cell contains spherical secretory granules of 2-3 microm in diameter. The granules are filled with highly electron-dense materials near the nucleus but have lower electron-density near the central cell. The secretory granules contained in the b cell have an irregular shape and are 1-1.5 microm in diameter. The density of the materials in the granules is uniform throughout the cytoplasm. The secretory granules contained in both the a and b cells are produced by the rough endoplasmic reticulum. Materials in the granules are exocytotically discharged into the secretory apparatus inside the secretory cell, sent to the extracellular channels in the central cell, and secreted through the canal cell. The rosette gland can be distinguished from the epidermal cells 2 weeks after egg-laying and the gland matures just before hatching. Materials produced by this gland are secreted after hatching and secretion continues through five stages of zoeal larvae. These rosette glands were never found in the megalopal larva. Rosette glands are found in the embryos of Sesarma spp. and Uca spp. In other crabs, tegumental glands are also found at the same position as in the embryo of S. haematocheir, but the fine structure of their glands is largely different from that of the rosette gland. On the basis of the morphology of secretory cells (a-g cell types), the tegumental glands of a variety of crab embryos can be classified into four types, including rosette glands (type I-IV). The function of these tegumental glands is not yet known, but different types of the gland seem to reflect the phylogeny of the crabs rather than differences of habitat.


Asunto(s)
Braquiuros/embriología , Embrión no Mamífero/embriología , Glándulas Exocrinas/ultraestructura , Larva/crecimiento & desarrollo , Animales , Secreciones Corporales/fisiología , Braquiuros/citología , Braquiuros/crecimiento & desarrollo , Diferenciación Celular/fisiología , Citoplasma/metabolismo , Citoplasma/ultraestructura , Embrión no Mamífero/ultraestructura , Desarrollo Embrionario , Retículo Endoplásmico/metabolismo , Retículo Endoplásmico/ultraestructura , Células Epiteliales/metabolismo , Células Epiteliales/ultraestructura , Glándulas Exocrinas/metabolismo , Exocitosis/fisiología , Femenino , Larva/ultraestructura , Organogénesis/fisiología , Vesículas Secretoras/metabolismo , Vesículas Secretoras/ultraestructura , Especificidad de la Especie
5.
Protein Expr Purif ; 30(2): 171-8, 2003 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-12880765

RESUMEN

A gene coding for an esterase (PsEst1, 1911bp in length) of the psychrotrophic bacterium Pseudomonas sp. B11-1 isolated from Alaskan soil was cloned and sequenced. The deduced amino acid sequence revealed a protein of 637 amino acid residues with a molecular mass of 69 kDa. Although the expression product, PsEst1, showed no appreciable sequence similarity (less than 15% identity) to any known proteins with the established biochemical functions, it is expected to be related to the alpha/beta hydrolase superfamily because it shared sequence motifs that have been identified with this superfamily. For example, a unique 'nucleophilic elbow' motif, -Gly(36)-Asp-Ser-Leu-Asn(40)-, was identified, and Ser(38) was predicted to constitute a catalytic triad with Asp(162) and His(303). PsEst1 was overexpressed using a T7 RNA polymerase transcription (pET21a) system in the Escherichia coli BL21(DE3) cells as an inclusion body. A soluble denatured form of the enzyme was purified to homogeneity in the presence of 8M urea, and the catalytically active form of the enzyme could be obtained by subsequent removal of urea by dialysis, where the addition of 0.1% Triton X-100 was essential for the efficient renaturation of the enzyme. To our knowledge, this was the first example of the successful renaturation of the recombinant cold-adapted enzyme. The enzyme efficiently hydrolyzed vinyl and aryl esters with the C4-C6 acyl chain. The activation energy of the enzymatic p-nitrophenyl butyrate hydrolysis (20.1 kcal/mol at 10 degrees C) was significantly lower than the value (79.9 kcal/mol) of the mesophilic lipase. It was observed that the K(m) values for p-nitrophenyl butyrate in the growth temperature range of strain B11-1 (5-15 degrees C) were lower than those at higher temperatures.


Asunto(s)
Frío , Esterasas/biosíntesis , Esterasas/metabolismo , Pseudomonas/enzimología , Adaptación Fisiológica , Secuencia de Aminoácidos , Clonación Molecular , Estabilidad de Enzimas , Escherichia coli/genética , Esterasas/química , Esterasas/genética , Cinética , Datos de Secuencia Molecular , Renaturación de Proteína , Especificidad por Sustrato
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