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951.
Méndez AT Roig-López JL Santiago P Santiago C García-Arrarás JE 《Marine biotechnology (New York, N.Y.)》2000,2(3):231-240
The Echinodermata is a unique animal group forming an early branch in the deuterostomes phylogenetic tree. In echinoids and
asteroids a single Hox cluster with nine cognates of the vertebrate Hox paralogous groups has been reported, but no data are available from other echinoderm classes. We report here nine Hox-type sequences from the sea cucumber Holothuria glaberrima, a member of the class Holothuroidea. Partial homeodomain sequences were amplified by polymerase chain reaction from genomic
DNA and from a regenerating gastrointestinal tract complementary DNA library. Sequence analyses suggest that the holothuroid
cluster has at least three genes of the anterior, one of the medial, and five of the posterior groups. This is the first evidence
of five posterior sequences in echinoderms.
Received July 19, 1999; accepted October 18, 1999. 相似文献
952.
Association of the low-density lipoprotein receptor gene with obesity in Native American populations 总被引:3,自引:0,他引:3
Five low-density lipoprotein receptor gene (LDLR) restriction fragment length polymorphisms (RFLPs: TaqI, intron 4; HincII, exon 12; AvaII, exon 13; MspI and NcoI, exon 18) were investigated in 131 individuals from five Brazilian Indian tribes. All markers were polymorphic in this ethnic group. In the whole sample of Amerindians, 13 (41%) of the 32 expected haplotypes were identified, but only three were shared by all tribes. The Xavante, Suruí, Zoró, and Gavi?o tribes, who had been studied for anthropometry, were grouped according to their genotypes, and the corresponding mean values were examined. Significant associations were observed between HincII *H-, AvaII *A+, MspI *M-, and NcoI *N+ and the body mass index (BMI), triceps and subscapular skinfolds, and the arm fat index (AFI). Haplotypes were derived for these four RFLPs, and (*H-/*A+/*M-/*N+) haplotype carriers were compared with noncarriers of this haplotype with equally significant results for the three parameters (BMI, P=0.021; skinfold thickness, P<0.001; AFI, P=0.005). These results suggest that the LDLR gene has some influence over adipose tissue deposition. 相似文献
953.
Benintende GB López-Meza JE Cozzi JG Piccinetti CF Ibarra JE 《Current microbiology》2000,41(6):396-401
Several isolates of Bacillus thuringiensis native to Argentina obtained in a nationwide screening program showed atypical crystal morphology. One of these strains,
INTA 51-3, was further characterized in order to determine other features like protein composition of its parasporal crystal,
plasmid pattern, identification of cry genes and toxicological properties. B. thuringiensis INTA 51-3 (serovar tohokuensis) had an amorphous inclusion containing a major protein component of ca. 130 kDa. After trypsin digestion of solubilized crystals, SDS-PAGE resolved a unique protease-resistant peptide of ca. 90 kDa. The plasmid pattern from INTA 51-3 resembled that of the standard strain HD-1. However, Southern analysis showed
no hybridization to fragments of cry1Aa, cry2Aa, cry3A, and cry11A genes. Degenerate primers were used for identification of the cry1 genes by PCR. Nevertheless, the presence of cry1 type gene(s) in B. thuringiensis INTA 51-3 was confirmed. Highly concentrated crystal suspensions showed to be weakly toxic only to lepidopteran species.
Received: 23 May 2000 / Accepted: 26 June 2000 相似文献
954.
The association of tubulin carboxypeptidase with microtubules has been demonstrated in crude brain extracts and in living non-nervous cells. Here, we studied this phenomenon in cultured brain cells. To determine the association of the enzyme with neural microtubules we isolated the cytoskeletons (detergent-extraction under microtubule-stabilizing conditions) and measured the content of Tyr, Glu, and 2 tubulin as a function of the in vitro incubation time of the cytoskeletons. The carboxypeptidase was found associated with microtubules in 2 days-cultured cells but not in 7 days-cultured cells. Quantitative analysis of digitized images after immunofluorescent staining revealed that detyrosination during the incubation of the cytoskeletons occurred preferentially in the distal regions of the neural processes. Prolonged taxol-treatment of the cells promoted higher detyrosination but Tyr tubulin was not depleted suggesting the existence of a subset of microtubules that has not associated carboxypeptidase and therefore cannot be detyrosinated even after prolonged taxol-treatment. This hypothesis was supported, although not conclusively, by additional experiments. 相似文献
955.
Ricardo Barra Juan Carlos Colombo Gabriela Eguren Nadia Gamboa Wilson F. Jardim 《Neurochemical research》2000,25(1):1-1
Dedication
Special Issue Dedicated to Dr. Héctor S. Barra 相似文献956.
Astyanax scabripinnis specimens from four distinct populations in Brazil were studied with respect to their karyotype macrostructure, nucleolar
organizer regions, and 18S and 5S rRNA genes. The four populations showed a 2n = 50 chromosomes (3 M + 11 SM + 5 ST + 6 A pairs) and 1–2 B chromosomes. No chromosomal differentiations were observed between
sexes. Although a karyotypic diversity has been characterized in this fish group, the populations now analyzed presented the
same macrokaryotypic pattern. Chromosome mapping of 5S rDNA showed a total of eight sites located in four distinct chromosomal
pairs, with no apparent differences among populations. A comparative study on 18S rDNA locations and Ag-NORs showed some secondary
NOR sites that are not usually expressed in karyotypes and a probable differential NOR activity among populations. Correlations
between these data, environmental conditions and B chromosomes are discussed.
This revised version was published online in July 2006 with corrections to the Cover Date. 相似文献
957.
Specimens of Astyanax scabripinnisfrom three different altitudes (1920, 1800 and 700?m) along the Ribeirão Grande stream in the Campos do Jordão region (São Paulo State, Brazil) were investigated. The same diploid number, 2n?=?50, was detected in the three populations, with the following karyotypic constitution: 6M, 22SM, 10ST and 12A. The populations located at 1920 and 1800?m altitude presented a high incidence of B chromosomes varying in number (0–2), shape (meta- and submetacentrics), size (large and small) and sex-related frequency (they were more frequent among females). The two morphologically variant B chromosomes probably evolved from a metacentric macrochromosome, which is the most commonly observed B chromosome in several A. scabripinnispopulations. 相似文献
958.
Novozym 435 (50 g l–1) catalyzed the synthesis of n-octyl--d-glucopyranoside lactate by transesterification between n-octyl--d-glucopyranoside (30 g l–1) and ethyl lactate (100 g l–1) in acetone. In 12 h, a molar yield of 87% n-octyl -d-glucopiranoside lactate was obtained at a overall conversion of 90%. 相似文献
959.
Guglielmone AA Mangold AJ Luciani CE Viñabal AE 《Experimental & applied acarology》2000,24(12):983-989
The findings of Amblyomma tigrinum in continental Argentina north of 40°S are presented according to phytogeographic domains (Andean–Patagonic, Amazonian and Chaco) and the seasonal distribution is depicted on a monthly basis. A total of 718 adult ticks and four nymphs were found. A. tigrinum ticks were present in all domains. Adult ticks were found all year round but they were more abundant during the summer. Most ticks were found on domestic dogs but the survey has a bias to domestic hosts. It is speculated that the cycle of immature is bound to shelters that mitigate extreme climatic conditions, thus explaining the finding of this tick species in contrasting ecological areas. 相似文献
960.
Blanca Lidia Arroyo-Flores Carlos Calvo-Méndez Arturo Flores-Carreón Everardo López-Romero 《Antonie van Leeuwenhoek》1998,73(4):289-297
Incubation of a mixed membrane fraction isolated from C. albicans yeast cells with Nonidet P-40 at a detergent/protein ratio as low of 0.025 (0.016–0.019%, w/v) yielded a soluble fraction that catalyzed the transfer of mannose from GDP-[14C] Man into dolichol phosphate mannose and from this intermediate into mannoproteins. Over 95% of the sugar in mannoproteins was O-linked as judged from its release after -elimination. Mannose was identified as the sole product after this treatment. Transfer activity did not depend on exogenous lipid acceptor indicating that the latter was solubilized along with the mannosyl transferases. Synthesis of mannolipid and mannoproteins occurred at optima temperatures of 20 °C and 37 °C, respectively, and at a pH in the range of 7.5-9.5. Mannosyl transfer into the mannolipid was stimulated by Mg2+and inhibited by Ca2+and Mn2+whereas mannoprotein labeling was stimulated by Mn2+and to a lower extent by Mg2+. When measured as a function of substrate concentration, the synthesis of the mannolipid was a nearly linear function of GDP-Man concentration in the range of 5 to 32 M whereas protein mannosylation exhibited hyperbolic kinetics with saturation reached at about 10 M. The solubilized preparation was able to utilize an exogenous source of mannolipid as sugar donor for protein mannosylation. Dinucleotides and, to a higher extent trinucleotides, inhibited mannosyl transfer into the mannolipid and hence into mannoproteins. 相似文献