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101.
A J de Araújo L F Ferreira U E Confalonieri L Nu?ez B M Ribeiro Filho 《Memórias do Instituto Oswaldo Cruz》1985,80(2):141-143
Enterobius vermicularis eggs were found in human coprolites collected in the archaeological site of Caserones, Tarapaca Valley, Chile, dating from 400 BC to 800 AD. The human pinworm had already been found in other pre-historic archaeological sites in America, and its introduction in this continent is discussed. 相似文献
102.
Summary Studies on intercalary regeneration in several organisms have shown that a regenerate is formed when surfaces of different positional value along the proximo-distal axis are opposed. One of the main problems posed by this phenomenon is to know which piece contributes to the building of the regenerate. In the present work we have studied this problem in planarians using chimaeras made between pieces of different body levels, irradiated or not, of the sexual and asexual races ofDugesia(S)mediterranea that differ in a chromosomal marker.The results found show very clearly that intercalary regenerates in planarians are formed by cells coming from both pieces (stumps), and that irradiated pieces keep the positional values and interact with non-irradiated pieces to restore the missing parts. This means that distal and proximal transformation do actually occur at the same time during intercalary regeneration in planarians. The implications of these results as regards to the origin of cells in the regenerate and to present models of intercalary regeneration are discussed. 相似文献
103.
Salvatore Oliviero Mario DeMarchi Angelo O. Carbonara Luigi F. Bernini Giuliano Bensi Giovanni Raugei 《Human genetics》1985,71(1):49-52
Summary The protein and gene structure of the Hp Johnson variant (Hp3) were analyzed in two related heterozygous individuals. The molecular weight (23kd) and amino acid composition of Hp3 alpha chain were in agreement with the triplicated structure first suggested by Smithies in 1964. Direct gene analysis by Southern blotting showed a three-fold tandem repeat of the same 1.7 kb DNA segment implicated in the Hp2 gene duplication. On the basis of these data a nine exon model for the Hp3 gene is proposed. 相似文献
104.
Dr. Manuel Megias Miguel A. Caviedes Francisco Rodriguez-Quiñones Antonio J. Palomares Francisco Ruiz-Berraquero 《Current microbiology》1985,12(6):325-328
Rhizobium trifolii was highly resistant to the lethal effect ofN-methyl-N-nitro-N-nitrosoguanidine (MNNG), but it was sensitive to the mutagenic action of this chemical. A concentration of 500g/ml yields a survival of between 1% and 10%, which allows us to obtain a higher number of mutants than lower concentrations that yield higher survival rates. Lethal damage produced by nitrosoguanidine was repaired, and repair is inhibited by acriflavine. 相似文献
105.
Dion tomasellii sp. nov. occurs with an interrupted distribution from Guerrero to central Sonora. It is characterized by falcate to subfalcate leaflets. The populations from Sonora and northern Sinaloa are segregated asD. tomasellii var.sonorense on the basis of their narrower and glaucous leaflets. 相似文献
106.
Richard M. Epand Karen Dell Witold K. Surewicz Mario A. Moscarello 《Journal of neurochemistry》1984,43(6):1550-1555
The capacity of myelin basic protein or of poly-L-lysine to promote leakage of carboxyfluorescein from vesicles or the aggregation of vesicles was studied. The vesicles were composed of phosphatidylcholine as the sole or major lipid component. Addition of 10% sphingomyelin, 10% phosphatidylglycerol, 10% egg or bovine brain phosphatidylethanolamine, or 30% dodecanal had relatively little effect on the extent of carboxyfluorescein release in the presence of either myelin basic protein or poly-L-lysine. In contrast with these results, the extent of vesicle aggregation was very sensitive to lipid composition. Addition of 10% phosphatidylglycerol induced more aggregation than the other phospholipids tested. Admixing 10% of a partially degraded sample of bovine brain phosphatidylethanolamine also led to a large amount of aggregation induced by the myelin basic protein. This latter aggregation appeared more specific for the basic protein, as it occurred to a much smaller extent with poly-L-lysine. In general, the effects of the myelin basic protein on either carboxyfluorescein release or vesicle aggregation were similar to, although somewhat greater than, that of poly-L-lysine. The aggregation of vesicles containing degradation products of phosphatidylethanolamine can be ascribed largely to the presence of aliphatic aldehydes. The effect of aliphatic aldehydes was specific in that the aliphatic alcohol, hexadecanol, or the short-chain aldehydes, acetaldehyde or butyraldehyde, did not promote myelin basic protein-induced vesicle aggregation. In addition, poly-L-lysine was less effective than the basic protein in aggregating vesicles containing aliphatic aldehydes. (ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
107.
Mario R. Tredici Teresa Papuzzo Luisa Tomaselli 《Applied microbiology and biotechnology》1986,24(1):47-50
Summary The results of a whole year experiment on the outdoor mass culture of Spirulina maxima strain 4Mx on fertilized sea-water are reported. Carbonate and phosphate precipitation in the sea-water media was prevented by maintaining a low concentration of phosphate and by controlling the pH in the range of 8.0–8.3. The mean annual yield of biomass on sea-water plus urea as nitrogen source was 7.35 g (dry weight) m-2· day-1, a value slightly lower than that obtained on the standard bicarbonate medium (8.14 g · m-2 · day-1). On sea-water plus nitrate the yield was only 5.2 g·m-2·day-1. The nitrogen content of the biomass was higher in summer and lower in winter. The seasonal effect was more evident when nitrate was the nitrogen source. 相似文献
108.
J Diaz-Mayans R Laborda A Nu?ez 《Comp. Biochem. Physiol. C, Comp. Pharmacol. Toxicol.》1986,83(1):191-195
The effects of hexavalent chromium on the motor activity and some metabolic aspects of albino rats were studied. 0.07 g Cr(VI)/l administered in drinking water produced no effects on the motor activity of rats, at least over 28 days of treatment. 0.7 g Cr(VI)/l in drinking water and 2 mg Cr(VI)/kg body wt injected i.p. significantly decreased the motor activity of rats after 7 days and 1 day, respectively. The treated rats showed a metabolic disadvantage in relation to the controls. The effects caused by Cr(VI) on the motor activity in rats could be an indication of the neurotoxicity of this metal. 相似文献
109.
J. Fernandez-Piqueras A. Rodriguez Campos C. Sentis Castaño E. Rojo Garcis 《Genetica》1983,61(1):9-12
The chromosomal location of the active NORs has been analyzed by a silver impregnation procedure in theSteropleurus martorelli complex. A primary NOR, which is always present at the first meiotic prophase, has been found in each of the four described races. In addition to this, all races possess one or two secondary NORs which are less active than the former and can be occasionally shown. Usually only one of the two homologous chromosomes has been found to be involved with nucleolus organisation.These results are discussed in relation to hypotheses on the chromosome differentiation of this species complex. 相似文献
110.
Microheterogeneity of bovine myelin basic protein studied by nuclear magnetic resonance spectroscopy
Myelin basic protein isolated from bovine white matter is known to consist of a mixture of three or more “charge isomers”, which can be separated by cation-exchange chromatography. We are using 360-MHz 1H-nmr spectroscopy to establish the chemical and structural differences among them. Preliminary studies by difference spectroscopy between two of the isomers suggest (a) all aromatic residues, and probably their nearest-neighbors, are unchanged; (b) the less cationic isomer lacks one (or two) of its C-terminal Arg residues; and (c) a significant fraction of the two Met residues in the less cationic isomer is present as methionine sulfoxide. 相似文献