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61.
A mycological survey was carried out on wheat heads from the main production area of Argentina. The isolation frequency and relative density of species from genus Fusarium and dematiaceous fungi were calculated. F graminearum was the predominant Fusarium species; similar to that observed in the USA and Canada. An analysis of deoxynivalenol (DON) natural contamination also was performed on a limited number (44) of samples. DON contamination levels in positive samples ranged from 0.2 to 30 ppm. A stepwise regression procedure showed that, among the species analysed, F. graminearum relative density was related to the DON contamination level and that other prevalent fungi did not influence or modify that relationship. 相似文献
62.
A physical map of the locations of the 5S rDNA genes and their relative positions with respect to 18S-5.8S-26S rDNA genes and a C genome specific repetitive DNA sequence was produced for the chromosomes of diploid, tetraploid, and hexaploid oat species using in situ hybridization. The A genome diploid species showed two pairs of rDNA loci and two pairs of 5S loci located on both arms of one pair of satellited chromosomes. The C genome diploid species showed two major pairs and one minor pair of rDNA loci. One pair of subtelocentric chromosomes carried rDNA and 5S loci physically separated on the long arm. The tetraploid species (AACC genomes) arising from these diploid ancestors showed two pairs of rDNA loci and three pairs of 5S loci. Two pairs of rDNA loci and 2 pairs of 5S loci were arranged as in the A genome diploid species. The third pair of 5S loci was located on one pair of A-C translocated chromosomes using simultaneous in situ hybridization with 5S rDNA genes and a C genome specific repetitive DNA sequence. The hexaploid species (AACCDD genomes) showed three pairs of rDNA loci and six pairs of 5S loci. One pair of 5S loci was located on each of two pairs of C-A/D translocated chromosomes. Comparative studies of the physical arrangement of rDNA and 5S loci in polyploid oats and the putative A and C genome progenitor species suggests that A genome diploid species could be the donor of both A and D genomes of polyploid oats. Key words : oats, 5S rDNA genes, 18S-5.8S-26S rDNA genes, C genome specific repetitive DNA sequence, in situ hybridization, genome evolution. 相似文献
63.
E. Molina Grima A. Robles Medina A. Giménez Giménez M. J. Ibáñez González 《Journal of applied phycology》1996,8(4-5):359-367
Eicosapentaenoic acid (EPA, 20:5n-3) was obtained from the microalgaPhaeodactylum tricornutum following a three-step process: fatty acid extraction by direct saponification of wet biomass, polyunsaturated fatty acid (PUFA) concentration by formation of urea inclusion compounds and EPA isolation by preparative HPLC. Direct saponification of wet biomass was carried out with KOH-ethanol (96% v:v) (1 h, 60 °C), extracting 91% of the EPA. PUFAs were concentrated by the urea method with an urea/fatty acid ratio of 4:1 at a crystallization temperature of 28 °C using methanol as the urea solvent. An EPA concentration ratio of 1.5 (55.2/36.3) and recovery of 79% were obtained. This PUFA concentrate was used to obtain 95.8% pure EPA by preparative HPLC, using a reverse-phase column (C18, 4.7 cm i.d. × 30 cm) and methanol-water (1% AcH) 80:20 w/w as the mobile phase. Ninety-seven per cent of EPA loaded was recovered and 70% EPA present in theP. tricornutum biomass was recovered in a highly pure form by means of this three-step downstream processing. In each of the HPLC preparative runs, 635 mg PUFA concentrate were loaded, obtaining 326 mg of a highly concentrated EPA fraction (2.46 g d–1). Finally, a preliminary cost statement has been calculated. 相似文献
64.
Villalba J. M. Navarro F. Roldán J. M. González-Reyes J. A. Navas P. 《Protoplasma》1994,178(3-4):87-96
Summary Expression of various sugar residues on the plasma membrane of frog (Rana perezi) epidermal cells at different stages of differentiation has been monitored with the use of a battery of HRP-conjugated lectins. In paraffin-embedded tissue, mannose residues (stained by Concanavalin A) were detected at the keratinocyte cell surface in all epidermal strata. However,Lens culinaris agglutinin (LCA), also specific for mannose, specifically stained the plasma membrane of cells from the stratum germinativum. Expression of N-acetyl-glucosamine (GlcNAc), labelled with wheat germ agglutinin (WGA), was maximum at the cell surface of basal cells and progressively decreased through the stratum spinosum. Galactose (Gal) and N-acetyl-galactosamine (GalNAc) residues, labelled withGriffonia simplicifolia I (GS I) andGlycine max (SBA) agglutinins, respectively, were expressed according to the degree of differentiation in amphibian epidermal cells. Sialic acid-containing glycoproteins, labelled withLimax flavus agglutinin (LFA), were found in the outermost plasma membrane of the replacement cell layer and stratum corneum. Glycoproteins responsible for the observed lectin-binding patterns have been identified by staining on nitrocellulose filters after electrophoresis of solubilized plasma membrane fractions and Western blotting. Changes at the level of glycosylation of plasma membrane glycoproteins as epidermal cells differentiate are discussed on the basis of a progressive addition of Gal residues. Integral membrane proteins have been solubilized with the non-denaturing detergent CHAPS and glycoproteins containing terminal Gal residues, that are expressed according to the degree of differentiation in frog epidermis, have been partially purified by affinity chromatography on a GS I-Sepharose 4 B column. The purified fraction was composed by four acidic glycoproteins with isoelectric points between 4.6 and 5.2 and, in SDS-gels gave five major protein bands with approximate molecular weights of 148, 140, 102, 60, and 52 kDa in SDS-gels. The 102 and 52 kDa bands correspond to the a and subunits of amphibian epidermal Na+,K+-ATPase as demonstrated by specific staining with a polyclonal antibody against the catalytic subunit of pig kidney proton pump and staining with lectins GS I, GS II, and WGA. Possible relationships between higher molecular weight proteins and the constituents of intramembranous particles from the outermost plasma membranes of the replacement cell layer and the stratum corneum are also discussed.Abbreviations BSA
bovine serum albumin
- CHAPS
(3-[(cholamidopropyl) dimethyl-ammonio] 1-propanesulfonate)
- Con A
Canavalia ensiformis agglutinin
- DTT
dithiothreitol
- Gal
galactose
- GalNAc
N-acetyl-D-galactosamine
- GlcNAc
N-acetyl-D-glucosamine
- GS I
Griffonia simplicifolia agglutinin I
- GS II
Griffonia simplicifolia agglutinin II
- HRP
horseradish peroxidase
- LFA
Limax flavus agglutinin
- LCA
Lens culinaris agglutinin
- NDPAGIF
non-denaturing polyacrylamide gel isoelectric focusing
- PAGE
polyacrylamide gel electrophoresis
- PAP
peroxidase-antiperoxidase
- PBS
phosphate buffered saline
- PMSF
phenyl methyl sulphonyl fluoride
- RCL
replacement cell layer
- SBA
soybean agglutinin (Glycine max)
- SB
stratum basal
- SDS
sodium dodecyl sulphate
- SG
stratum granulosum
- SS
stratum spinosum
- UEA I
Ulex europaeus agglutinin I
- WGA
wheat germ (Triticum vulgaris) agglutinin 相似文献
65.
Simultaneous high-biomass protein production and nutrient removal using Spirulina maxima in sea water supplemented with anaerobic effluents 总被引:1,自引:0,他引:1
E. J. Olguín B. Hernández A. Araus R. Camacho R. González M. E. Ramírez S. Galicia G. Mercado 《World journal of microbiology & biotechnology》1994,10(5):576-578
Maximum protein accumulation (71%, w/w) and nutrient removal by a mutant strain of Spirulina maxima growing on sea water supplemented with anaerobically treated pig slurry was achieved at 30°C with constant illumination (60 to 70 Em-2s-1), using a flow rate of 14.5 cm s-1 (20 rev. min-1 of a paddle wheel). Total phosphates were decreased by 99% and all ammonia-N was removed under these conditions.The authors are with the Department of Environmental Biotechnology, Institute of Ecology, Aptd Postal 63, Xalapa, Ver., Mexico 相似文献
66.
Javier Francisco-Ortega Richard H. Ellis Eduardo González-Feria Arnoldo Santos-Guerra 《Biodiversity and Conservation》1994,3(4):341-353
Germplasm of 21 diverse Argyranthemum taxa was collected from contrasting ecological zones in the Canary Islands. Seed dormancy was considerable in the majority of taxa. Extensive investigations, based on a germination test procedure algorithm for Asteraceae, with achenes from ray and disc florets of five contrasting taxa identified a procedure to promote full (85%) germination of the seeds from both ray and disc florets of all five taxa; viz, excision of the seeds from the achenes, followed by testing at 15°C with 2.6×10-3
m GA3 co-applied. Subsequent tests showed that this regime was effective in promoting full germination in seeds from both ray and disc florets of the remaining 16 taxa. The results are discussed in the context of ex situ plant germplasm conservation. 相似文献
67.
R. Hudson A. I. Melo G. González-Mariscal 《Journal of comparative physiology. A, Neuroethology, sensory, neural, and behavioral physiology》1994,175(5):573-579
It was the purpose of this study to test whether inhibition of estrus in the rabbit by short photoperiod could be simulated by subcutaneous implants of the pineal hormone melatonin. By measuring two non-invasive and readily quantifiable correlates of estrus, emission of the so-called nipple-search pheromone and scent-marking behavior (chinning), it was found that:
- In intact does kept in stimulatory long photoperiod, melatonin suppressed chinning but had no effect on emission of nipple-search pheromone.
- In intact, melatonin-treated does which were returned from inhibitory short day to stimulatory long day, chinning remained suppressed, whereas pheromone emission increased as for the vehicle-treated, control does.
- In ovariectomized does, estradiol administration stimulated both pheromone emission and chinning whereas melatonin failed to suppress these effects.
68.
Jesús Manuel de la Fuente Amalia Vázquez M. Mar González Miguel Sánchez María Molina César Nombela 《Applied microbiology and biotechnology》1993,38(6):763-769
Thermosensitive mutant strains of Saccharomyces cerevisiae that fail to generate an osmotically stable cell wall when grown at a non-permissive temperature release their cell contents upon expression of the mutation. Therefore, they may represent an alternative for the production of homologous or heterologous protein preparations. In order to analyse the expression of two of these mutations, lyt2 and slt2, we grew the corresponding strains under precisely defined conditions in batch and continuous fermentors. A switch in the temperature of batch cultures from 24° C to 37° C determined lysis of the cells with a significant release of intracellular enzymes. These include alkaline phosphatase and periplasmic proteins such as glucan-degrading enzymes, the pattern of cell lysis and protein release being maintained for about 6 h. One-stage continuous cultures of a lyt2 mutant were maintained for long periods at 37° C; a fraction of the population lysed and released the indicated proteins, but eventually a revertant of the lytic phenotype was selected. To avoid this, a two-stage continuous culture system was developed by connecting two fermentors in series, the effluent from the first one at 24°C being fed to the second one adjusted to 37° C. A steady state of cell lysis and protein liberation was reached in the second-stage fermentor without any evidence of selection of revertants. This system can be very useful for developing conditions for the use of yeast strains to produce protein preparations.
Correspondence to: C. Nombela 相似文献
69.
We present the results of a floristic study of intertidal species of Gelidiaceae collected in ten localities in the Bahía de Banderas region. The study area is within an extensive overlapping transitional zone between the tropical and subtropical regions of the Mexican Pacific coast. Species of the genera Gelidium and Pterocladia were found, G. microdentatum and G. pusillum being the most abundant and widely distributed in the Bay. The local and Mexican Pacific distribution for each species is given. The number of species found in this study is compared with the numbers reported in the literature for the Mexican Pacific. 相似文献
70.
Sonja K. Glasser Martín Hesajim de Santiago-Hernández Oliverio Delgado-Carrillo Luis Alberto Villanueva Espino Adonaji Cortés Pérez Antonio González-Rodríguez Rafael Lira-Saade Mauricio Quesada 《American journal of botany》2023,110(5):e16170