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81.
Agar yield and quality of Gracilaria chilensis (Gigartinales,Rhodophyta) in tank culture using fish effluents 总被引:1,自引:0,他引:1
Tank cultivation of Gracilaria using fish effluents has permitted a production of 48 kg m–2 yr–1 and can reduce the dissolved nitrogen loads in the seawater. We report the yield, gel strength, gelling and melting point of agar from Gracilaria cultivated in tanks with seawater previously utilized in intensive, land-based salmon cultures and compared to a control using directly pumped seawater, over a study period of 22 months. The results show that the highest agar yield (20 to 22%) was obtained when Gracilaria was cultivated with pure seawater as compared to the fish effluents. The gel strength, gelling and melting point were higher in the agar obtained from algae cultured with fish effluents. During the spring, the gel strength, gelling and melting point increased in tanks with fish effluents and decreased in tanks with a supply of pure seawater. 相似文献
82.
Carlos Hermenegildo Goizane Marcaida Carmina Montoliu Santiago Grisolía María-Dolores Miñana Vicente Felipo 《Neurochemical research》1996,21(10):1237-1244
We proposed that acute ammonia toxicity is mediated by activation of NMDA receptors. To confirm this hypothesis we have tested
whether different NMDA receptor antagonists, acting on different sites of NMDA receptors, prevent death of mice induced by
injection of 14 mmol/Kg of ammonium acetate, a dose that induces death of 95% of mice. MK-801, phencyclidine and ketamine,
which block the ion channel of NMDA receptors, prevent death of at least 75% of mice. CPP, AP-5, CGS 19755, and CGP 40116,
competitive antagonists acting on the binding site for NMDA, also prevent death of at least 75% of mice. Butanol, ethanol
and methanol which block NMDA receptors, also prevent death of mice. There is an excellent correlation between the EC50 for preventing ammonia-induced death and the IC50 for inhibiting NMDA-induced currents. Acute ammonia toxicity is not prevented by antagonists of kainate/AMPA receptors, of
muscarinic or nicotinic acetylcholine receptors or of GABA receptors. Inhibitors of nitric oxide synthase afford partial protection
against ammonia toxicity while inhibitors of calcineurin, of glutamine synthetase or antioxidants did not prevent ammonia-induced
death of mice. These results strongly support the idea that acute ammonia toxicity is mediated by activation of NMDA receptors. 相似文献
83.
Naoto Rikitomi Papa Salif Sow Kiwao Watanabe Duilio S. Nunez Glenda Martinez Tsuyoshi Nagatake 《Microbiology and immunology》1996,40(12):899-905
The susceptibility of 101 pneumococcal isolates from the respiratory tract during 1991–1994 was examined and compared with the susceptibility of isolates over the period of 1975–1990. A rapid increase of resistance was seen not only to penicillin but also other antimicrobial agents. During 1991–1994, 38% of all the isolates were resistant to penicillin. The rates of resistance during this period were 16–23% for three newer cephalosporins, 18% for imipenem, 69% for tetracycline, 31% for erythromycin, 20% for chloramphenicol and 9% for clindamycin. The use of antibiotics within one month prior to pneumococcal isolation was correlated with penicillin resistance (P < 0.05). Serotyping of the isolates by antiserum revealed differences in predominant types between penicillin-resistant (19F, 23F, 4) and -susceptible isolates (15, 4, 11A). Our data suggests that anti-pneumococcal antibiotics should be carefully chosen on the basis of susceptibility tests. 相似文献
84.
J. Martin Sanchez F. Ruiz Martinez J. M. Salinas Martinez de Lecea C. Sanchez Rabasco C. Acedo Sanchez M. C. Sanchiz Marin V. Delgado Florencio F. Morillas Marquez 《Systematic parasitology》1996,33(3):177-182
This study presents the results of the characterisation of 17 strains ofLeishmania by isoenzyme electrophoresis from a focus of leishmaniasis in southern Spain: two from human visceral leishmaniasis, four from human cutaneous leishmaniasis and 11 from sandflies. The 17 strains are grouped in 6 zymodemes characterised by their variability as regards to the electrophoretic mobility of the enzymes MDH, G6PD, NP and ME. Thus, we confirm the high intraspecific variability ofLeishmania (L.) infantum in a focus of southern Spain, as already suggested by previous studies. Zymodemes GR-15 and GR-17 are also described for the first time in Spain, and they characteristically possess the same relative electrophoretic mobility in the enzyme ME (93). Sixteen zymodemes of theL. infantum complex found in southern Spain were numerically analysed on the basis of the enzymatic profiles of 122Leishmania strains characterised from this area. 相似文献
85.
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
86.
Verónica Lipperheide Guillermo Quindós Yolanda Jiménez José Pontón José Vicente Bagán-Sebastián José Manuel Aguirre 《Mycopathologia》1996,134(2):75-82
Prevalence of yeasts in 35 leukoplakia and 34 oral lichen planus patients was compared with that observed in persons without oral diseases. Serotype and morphotype were determined on Candida albicans isolates. Yeasts were isolated from the oral cavity specimens of 43.7% of the patients. C. albicans (serotype A) was the predominant species (76% in leukoplakia, 88.2% in lichen planus and 60.8% in healthy persons). Sixteen morphotypes were encountered on malt extract agar, being 732, 733, 734, 753 and 754 the most frequently found. Morphotypes SP1N and SP1Y were the most common on Sabouraud-trypheniltetrazolium agar (68.4% of the isolates from leukoplakia and 73.3% from lichen planus, but only 46.6% of the isolates from healthy oral mucosa showed SP1N morphotype). Presence of oral lesions was associated with a marked reduction in the yeast species and C. albicans biotypes, suggesting that C. albicans and particularly some of its biotypes, show a high potential of adaptation to the changes associated with the development of oral leukoplakia and lichen planus. 相似文献
87.
I Martinez de la Fuente L Martinez J Veguillas J M Aguirregabiria 《Biophysical journal》1996,71(5):2375-2379
The numerical study of a glycolytic model formed by a system of three delay differential equations reveals a quasiperiodicity route to chaos. When the delay changes in our biochemical system, we can observe the emergence of a strange attractor that replaces a previous torus. This behavior happens both under a constant input flux and when the frequency of the periodic substrate input flux changes. The results obtained under periodic input flux are in agreement with experimental observations. 相似文献
88.
Jean-Alain Fehrentz Corine Genu-Dellac Muriel Amblard Franclois Winternitz Albert Loffet Jean Martinez 《Journal of peptide science》1995,1(2):124-131
N-Urethane-protected N-carboxyanhydrides (UNCAs) are very reactives. They have been successfully used in peptide synthesis, in both solution and solid phase. We have demonstrated that UNCAs are interesting starting materials for the synthesis of various amino acid derivatives. Chemoselective reduction of UNCAs with sodium borohydride led the corresponding N-protected β amino alcohols. Reaction of UNCAs with Meldrum's acid, followed by cyclisation, yielded enantiomerially pure tetramic acid derivatives. Diastereoselective reduction of tetramic acid derivatives produced (4S,5S)-N-alkoxycarbonyl-4-hydroxy-5-alkylpyrrolidin-2-ones derived from amino acids, which after hydrolysis yielded statine and statine analogues. Tetramic acid derivatives could also be obtained by reaction of UNCAs with benzyl ethyl followed by hydrogenolytic deprotection and decarboxylation. UNCAs also reacted with phosphoranes to produce the ketophosphorane in excellent yields. Subsequent oxidation with oxone or with [bis(acetoxy)-iodol]-benzene produced vicinal tricarbonyl derivatives. These reactions usually proceeded smoothly and with high yields. 相似文献
89.
Iciar Martinez Bent Dreyer Aasta Agersborg Annick Leroux Gilles Boeuf 《Comparative biochemistry and physiology. Part B, Biochemistry & molecular biology》1995,112(4)
Rearing of 1-year-old Arctic charr (Salvelinus alpinus) at 12°C, as well as the administration of 50 or 75 mgT3/kg feed, accelerated the neonatal to adult fast myosin heavy chain transition, but the effect of temperature was more dramatic than the effect of T3 administration. The endogenous plasma levels of T3 in charrs reared at 12°C were higher than those of analogous groups reared at natural temperature, which in the period under study was between 0.5 and 12°C. As in other species, T3 seemed to play a role in the regulation of the neonatal to adult fast myosin isoform transition by down-regulating the levels of the neonatal and increasing the levels of an adult fast myosin heavy chain. Temperature seemed to accelerate this transition at least, but not only, by inducing an increase in the endogenous levels of T3 in the Arctic charr. 相似文献
90.
Francisco M. Pinto Yves Chupeau Vicente M. Cabrera 《In vitro cellular & developmental biology. Plant》1995,31(2):96-100
An efficient and easy method for genetic characterization of plant somatic hybrids is proposed. In a first qualitative approach,
four somatic hybrids and their parental species (Nicotiana tabacum andN. plumbaginifolia) were characterized by DNA fingerprinting and Random Amplification of Polymorphic DNA (RAPD). After this, a quantitative
estimation of the degree of parental contribution to the hybrids was carried out by means of a slot-blot analysis. Both qualitative
methods, showed one hybrid identical toN. tabacum, two almost identical toN. plumbaginifolia, and a fourth similar to this parental species, but with someN. tabacum admixture. The quantitative method, for the same hybrids, gave 83%, 7%, 7%, and 37%N. tabacum DNA contribution, respectively. 相似文献