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21.
The pelagic larval duration ( D PL ) for 10 temperate cryptobenthic species belonging to three families: Gobiidae, Gobiesocidae and Blenniidae was investigated. Overall, the Gobiesocidae presented short D PL s varying between 11 and 18 days, the Gobiidae's D PL ranged between 14 and 39 days, and Parablennius pilicornis (Blenniidae) had an average of 33 days (range 31–37 days). Two subtypes of settlement marks were found among individuals of the same species. 相似文献
22.
C González-Bosch V J Miralles J Hernández-Yago S Grisolía 《Biochemical and biophysical research communications》1987,146(3):1318-1323
Apocytochrome c, the cytosolic precursor of cytochrome c, competes with the precursor of ornithine carbamoyltransferase (OCT) for entry into isolated rat liver mitochondria. 相似文献
23.
Spermidine and spermine stimulate the transport of the precursor of ornithine carbamoyltransferase into rat liver mitochondria 总被引:1,自引:0,他引:1
C González-Bosch V J Miralles J Hernández-Yago S Grisolia 《Biochemical and biophysical research communications》1987,149(1):21-26
We have examined the effect of low molecular weight components of the transport mixture generally used for the import of rat liver pre-ornithine carbamoyltransferase by isolated rat liver mitochondria. These studies revealed that spermidine and spermine, at physiological concentrations, stimulate the transport of the precursor of ornithine carbamoyltransferase into mitochondria. This stimulatory effect of spermidine and spermine is concentration-dependent and is completely inhibited at higher than physiological concentrations (20 mM for spermidine and 4 mM for spermine). Magnesium ions, which also have a stimulatory effect, inhibit the stimulatory effect of spermidine. 相似文献
24.
Pedro Acevedo-Rodríguez 《Brittonia》1987,39(3):348-352
Two new Brazilian species,Serjania fluminensis andS. unidentata, are described, illustrated, and discussed. 相似文献
25.
J A García-Sáinz S M Hernández-Sotomayor J L Contreras-Rodríguez M Macías-Silva 《Biochemistry international》1989,18(1):243-249
The stimulations of ureagenesis and cyclic AMP accumulation induced by glucagon were inhibited by 10 nM vasopressin or 100 nM phorbol 12-myristate 13-acetate (PMA). The maximal accumulation of cyclic AMP induced by glucagon was clearly diminished by these agents without change in the EC50 for the peptide hormone suggesting a non-competitive type of inhibition. H-7 blocked the inhibition of glucagon-stimulated ureagenesis induced by PMA and vasopressin and diminished their effect on the accumulation of cyclic AMP induced by glucagon. It is concluded that activation of protein kinase C inhibits the stimulation of ureagenesis and the accumulation of cyclic AMP induced by glucagon in liver cells from hypothyroid rats; H-7 inhibits the effects of protein kinase C activation. 相似文献
26.
A similar protein portion for two exoglucanases secreted by Saccharomyces cerevisiae 总被引:4,自引:0,他引:4
Exoglucanase (exo-1,3-β-D-glucan glycohydrolase, EC 3.2.1.56) activity secreted by Saccharomyces cerevisiae into the culture medium was separated by ion exchange chromatography into two glycoprotein isoenzymes which contributed 10%
(exoglucanase I) and 90% (exoglucanase II) towards the total activity. Analysis of the “in vitro” deglycosylated products
by polyacrylamide gel electrophoresis under native or denaturing conditions indicated that the protein portions of both exoglucanases
exhibited identical mobility, each one consisting of two polypeptides with M
r of 47000 and 48000. The same profile was shown by the exoglucanase secreted in the presence of tunicamycin. Antibodies raised
against the protein portion of exoglucanase II did react with both native exoglucanases and their deglycosylated products
with a pattern indicative of immunological identity. Digestion of the “in vitro” deglycosylated products of both exoglucanases
with Staphylococcus aureus V-8 protease or trypsin generated the same proteolytic fragments in each case. Only exoglucanase II was secreted by protoplasts.
These and previously reported results indicate that the protein portions of both isoenzymes may be the product of the same
gene (or a family of related genes), and that exoglucanase I is a product of enzyme II, modified by a process occurring beyond
the permeability barrier of the cell. 相似文献
27.
V J Miralles C González-Bosch M J Marcote J Hernández-Yago S Grisolía 《Archives of biochemistry and biophysics》1989,275(1):224-227
The precursor of ornithine carbamoyltransferase can be transported in vitro into rat liver mitochondria using the postmitochondrial supernatant from rat liver, a more homologous medium than the commonly used rabbit reticulocyte lysate. The transport of the precursor in the case of reticulocyte lysate requires a standard translation mixture. In the presence of the postmitochondrial supernatant the same is true. However, when the components of the translation mixture were added individually to the postmitochondrial supernatant, it was found that spermidine or spermine, at physiological concentrations, sufficed for the transport of the precursor of ornithine carbamoyltransferase. The activity of the postmitochondrial supernatant was inactivated by trypsin and slightly decreased by RNase treatment; it was not lost by dialysis or by heating at 100 degrees C. 相似文献
28.
Pedro J. N. Silva Richard K. Koehn Walter J. Diehl III Robin P. Ertl Elaine B. Winshell Mauro Santos 《Biochemical genetics》1989,27(7-8):451-467
Four samples of the musselMytilus edulis were taken between 1984 and 1987 from Stony Brook, New York, and used to study the glucose-6-phosphate isomerase (GPI) polymorphism
in this species.In vitro specific activity andin vivo flux measured in the same animals were found to be significantly correlated. A significant effect of GPI genotype on flux
was observed in one of the samples; overall, significant evidence of effect of genotype on enzyme activity was also obtained.
GPI activities of common genotypes tend to deviate less from the population mean than those of rare (frequency less than 5%)
genotypes. This suggests the possibility that rare GPI genotypes are rare as a consequence of having biochemical properties
that deviate from an optimum level and, therefore, having a lower fitness. In support of this hypothesis, we found in one
of our samples that shell length is a concave function of GPI activity with an intermediate optimum activity level.
The financial support provided to P.J.N.S. by the Luso-American Educational Commission (Fulbright Program), the Instituto
Nacional de Investigacao Científica (Portugal), and the Faculdade de Ciências da Universidade de Lisboa during several stages
of this research is gratefully acknowledged. Financial support from the Ministerio de Educatión y Ciencia (Spain) in the form
of a postdoctoral Fulbright/MEC fellowship to M.S. is also gratefully acknowledged. Research was supported by National Science
Foundation Grant BSR-8415060 to R.K.K. This is contribution No. 736 from the Program in Ecology and Evolution, State University
of New York at Stony Brook.
On leave from Departamento de Biologia Vegetal, Faculdade de Ciências, Universidade de Lisboa, Campo Grande C2, Lisboa, Portugal. 相似文献
29.
J M Afonso M Hernández J M Larruga V M Cabrera A M González 《Human biology; an international record of research》1989,61(4):543-549
We analyzed the genetic polymorphism of eight red cell enzymes in samples from different geographical areas of Tenerife and the Iberian peninsula. The gene frequency heterogeneity found within the Tenerife samples was at the same level as that of Tenerife-mainland comparisons. The presence of the Negroid G6PD A+ allele in the Tenerife samples is evidence of an African admixture with a mean estimation of 4.5%. 相似文献
30.
Enrique Palacián Pedro J. González Manuel Piñeiro Francisco Hernández 《Molecular and cellular biochemistry》1990,97(2):101-111
Dissociation of protein-containing structures by modification of protein amino groups with dicarboxylic acid anhydrides is a mild procedure which, in some cases, offers advantages over treatment with alternative dissociating agents, such as urea, guanidine hydrochloride, detergents, high ionic strength, and extremes of pH: In addition to dissociating multimeric proteins and protein aggregates, dicarboxylic acid anhydrides are effective dissociating agents for membrane-bound proteins and nucleoprotein particles. With most dicarboxylic acid anhydrides reviewed, the introduced reagent residues can be eliminated under moderate acid conditions, which allows the purification of unmodified individual components, and the use of disassembly-reconstitution systems valuable for investigating the structural and functional roles played by the individual components of complex particles:Each reagent can be suitable for a particular purpose, depending on the required specificity of the modification and stability of the modified groups: The stability of the acylated amino groups ranges from the very stable succinylated amino groups to the very labile acylation obtained with dimethylmaleic anhydride: Between these extremes, the stability of the modified amino groups decreases stepwise in the following order: maleic, exo-cis-3,6-endoxo-4-tetrahydrophthalic, citraconic, and 3,4,5,6-tetrahydrophthalic anhydride. With respect to the selectivity of the produced modification, little or no modification of hydroxyamino acid and cysteine residues has been observed with dimethylmaleic, exo-cis-3,6-endoxo-4-tetrahydrophthalic, and 3,4,5,6-tetrahydrophthalic anhydrides: With the other reagents, the extent of modification of hydroxyamino acid residues increases in the order citraconic, maleic and succinic anhydride: Citraconic and maleic anhydrides can produce irreversible modification of cysteine residues, the reactivity of sulfhydryl groups being higher with maleic anhydride: 相似文献