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541.
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Julio Pérez-Díaz Angeles Martín Requero Matilde S. Ayuso-Parrilla Roberto Parrilla 《Life sciences》1977,20(9):1599-1605
Glucose decreases the oxygen utilization by isolated rat lung cells. Its effect displays saturation type kinetics with a “Ki” of 2.2. mM. The similarity of this value with the reported “Km” of 2.4 mM described for glucose uptake by these cells, suggests that both processes may be intimately related and both of them are under the control of the same rate limiting step. Several arguments point to glucose transport into these cells as the most important rate limiting step for its utilization: 1) Phloridzin prevented glucose inhibition of oxygen uptake while mannoheptulose did not; 2) The activity of hexokinase which is the least active glycolytic enzyme in these cells far exceeded the observed rates of glucose utilization and a decrease of 45 per cent in its activity in starved animals did not affect the rate of glucose uptake; 3) The “Km” of hexokinase for glucose is two orders of magnitude below the observed “Km” for glucose uptake and the “Ki” for glucose inhibition of respiration. 相似文献
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545.
Paenibacillus larvae is the causative agent of American Foulbrood (AFB), the most severe bacterial disease that affects honeybee larvae. AFB causes a significant decrease in the honeybee population affecting the beekeeping industry and agricultural production. After infection of larvae, P. larvae secretes proteases that could be involved in the pathogenicity. In the present article, we present the secretion of different proteases by P. larvae. Inhibition assays confirmed the presence of metalloproteases. Two different proteases patterns (PP1 and PP2) were identified in a collection of P. larvae isolates from different geographic origin. Forty nine percent of P. larvae isolates showed pattern PP1 while 51% exhibited pattern PP2. Most isolates belonging to genotype ERIC I - BOX A presented PP2, most isolates belonging to ERIC I - BOX C presented PP1 although relations were not significant. Isolates belonging to genotypes ERIC II and ERIC III presented PP2. No correlation was observed between the secreted proteases patterns and geographic distribution, since both patterns are widely distributed in Uruguay. According to exposure bioassays, isolates showing PP2 are more virulent than those showing PP1, suggesting that difference in pathogenicity could be related to the secretion of proteases. 相似文献
546.
Javier Velasco-Vázquez Matilde Arnay-de-la-Rosa Emilio González-Reimers Oscar Hernández-Torres 《Biological trace element research》1997,60(3):235-241
In order to deepen our knowledge of the dietary habits of the prehispanic inhabitants of El Hierro, we have determined bone
strontium (Sr), manganese (Mn), magnesium (Mg), copper (Cu), zinc (Zn), and calcium (Ca) in 52 human tibiae (23 belonging
to males and 20 to females individuals) buried in a single burial cave; in 21 modern individuals who served as controls; and
in 11 bones of herbivores found at archeological sites of the Canary Islands. Results suggest that females consumed a more
vegetarian diet, although site-corrected Sr/Ca ratio of both males and females speaks for a mixed-diet consumption. 相似文献
547.
Lucio Cocco Matilde Y. Follo Irene Faenza Alberto Bavelloni Anna Maria Billi Alberto M. Martelli Lucia Manzoli 《Advances in enzyme regulation》2007,47(1):2-9
Location impinges on function of some of the main players of nuclear inositol lipid cycle. Here we have discussed the behavior of PI-PLCβ1 in myelodysplastic and cultured leukemia cells.The presence of a cryptic deletion of PI-PLCβ1 gene in high-risk MDS patients is accompanied by altered expression of its mRNA in that the overall decrease of mRNA is characterized by a dramatic decrease of the splicing variant 1a, which is cytosolic and partially nuclear, whilst the splicing variant 1b is still highly represented. This suggests that altered expression of nuclear PI-PLCβ1 could be involved in a disregulation of the cell cycle and have also important effects on cell apoptotic pathways.Moreover, in cultured leukemia cells (Felc) it has been reported by means of a proteomic approach that the splicing factor SRp20 interacts with nuclear PI-PLCβ1 and its expression is modulated by this signaling molecule.All in all, it appears more and more evident that nuclear signaling elicited by PI-PLCβ1 is a key event in the control of cell cycle progression. 相似文献
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549.
Empar Vengut-Climent Montserrat Terrazas Ricardo Lucas Matilde Arévalo-Ruiz Ramón Eritja Juan Carlos Morales 《Bioorganic & medicinal chemistry letters》2013,23(14):4048-4051
Oligoribonucleotide conjugates carrying apolar carbohydrates at the 5′-end and the corresponding siRNA duplexes have been prepared using phosphoramidite chemistry. All the carbohydrate-siRNA derivatives were compatible with RNA interference machinery if transfected with oligofectamine. In the absence of a transfection agent, some of them exerted certain reduction of gene expression. Double-tailed permethylated glucose conjugated to siRNA through a long spacer inhibited gene expression up to 26% compared to the scrambled duplex. Such modifications contribute positively to the stability of oligoribonucleotides against 5′-exonuclease degradation. 相似文献