排序方式: 共有32条查询结果,搜索用时 15 毫秒
21.
RH Behrens Z Bisoffi A Björkman J Gascon C Hatz T Jelinek F Legros N Mühlberger P Voltersvik 《Malaria journal》2006,5(1):1-4
Background
Thick blood films are routinely used to diagnose Plasmodium falciparum malaria. Here, they were used to diagnose volunteers exposed to experimental malaria challenge.Methods
The frequency with which blood films were positive at given parasite densities measured by PCR were analysed. The poisson distribution was used to calculate the theoretical likelihood of diagnosis. Further in vitro studies used serial dilutions to prepare thick films from malaria cultures at known parasitaemia.Results
Even in expert hands, thick blood films were considerably less sensitive than might have been expected from the parasite numbers measured by quantitative PCR. In vitro work showed that thick films prepared from malaria cultures at known parasitaemia consistently underestimated parasite densities.Conclusion
It appears large numbers of parasites are lost during staining. This limits their sensitivity, and leads to erroneous estimates of parasite density. 相似文献22.
Djian P; Phillips M; Easley K; Huang E; Simon M; Rice RH; Green H 《Molecular biology and evolution》1993,10(6):1136-1149
The involucrin genes of the mouse (Mus musculus) and the rat (Rattus
norvegicus) have been cloned and sequenced. The coding region of each gene
contains, at site P, a segment of repeats homologous to that of other
nonanthropoid mammals. In contrast to the repeats of species belonging to
different mammalian orders, many individual repeats of the mouse and the
rat can be matched. Both before and after the divergence of the two
species, these repeats have been the site of systematic alterations in
nucleotide sequence. One of the alterations is the correction of
nucleotides of one repeat by those of another. Corrected nucleotides may be
closely linked to flanking nucleotides that are uncorrected; the systematic
correction process therefore appears to be due to gene conversion. There is
a stretch of 18 reiterated CAGs in the segment of repeats of the Mus gene;
most of these reiterations were introduced recently, supporting the idea
that the gene was generated originally from poly CAG. An antiserum to a
synthetic peptide encoded by the segment of repeats of the Mus gene reveals
differentiation- specific expression of the gene in the epidermis.
相似文献
23.
Regina Helena Geribello Priolli Philip Traldi Wysmierski Camila Pinto da Cunha José Baldin Pinheiro Natal Antonio Vello 《Genetics and molecular biology》2013,36(3):382-390
Soybean is one of the most valuable and profitable oil crop species and a thorough knowledge of the genetic structure of this crop is necessary for developing the best breeding strategies. In this study, a representative collection of soybean cultivars recommended for farming in all Brazilian regions was genotyped using 27 simple sequence repeat (SSR) loci. A total of 130 alleles were detected, with an average allelic number of 4.81 per locus. These alleles determined the core set that best represented this soybean germplasm. The Bayesian analysis revealed the presence of two clusters or subgroups within the whole collection (435 soybean cultivars) and the core set (31 entries). Cultivars of similar origin (ancestral) were clustered into the same groups in both analyses. The genetic diversity parameters, based on the SSR loci, revealed high similarity between the whole collection and core set. Differences between the two clusters detected in the core set were attributed more to the frequency of their ancestors than to their genetic base. In terms of ancestry, divergent groups were presented and a panel is shown which may foster efficient breeding programs and aid soybean breeders in planning reliable crossings in the development of new varieties. 相似文献
24.
GW Patton R Stephens IA Sidorov X Xiao RA Lempicki DS Dimitrov RH Shoemaker G Tudor 《BMC bioinformatics》2006,7(1):81
Background
Microarrays used for gene expression studies yield large amounts of data. The processing of such data typically leads to lists of differentially-regulated genes. A common terminal data analysis step is to map pathways of potentially interrelated genes. 相似文献25.
26.
Lauren RH Krumpe Kathryn M Schumacher James B McMahon Lee Makowski Toshiyuki Mori 《BMC biotechnology》2007,7(1):65
Background
Amino acid sequence diversity is introduced into a phage-displayed peptide library by randomizing library oligonucleotide DNA. We recently evaluated the diversity of peptide libraries displayed on T7 lytic phage and M13 filamentous phage and showed that T7 phage can display a more diverse amino acid sequence repertoire due to differing processes of viral morphogenesis. 相似文献27.
28.
Abreu AG Priolli RH Azevedo-Filho JA Nucci SM Zucchi MI Coelho RM Colombo CA 《Genetics and molecular biology》2012,35(1):119-121
Acrocomia aculeata is a perennial, fruit-producing palm tree, native to tropical forests. Its fruits have spurred interest because of their significant potential for use in the cosmetic industry and as feedstock for biofuel. In the present study, the genetic structure and mating system in Acrocomia aculeata were analyzed, using eight nuclear micro-satellite loci and samples from São Paulo and Minas Gerais states, Brazil. By means of Bayesian analysis, these populations were clustered into two or three groups. A high multilocus outcrossing rate suggests that outcrosses were predominant, although a certain degree of biparental inbreeding also occurred. Thus, although monoecious and self-compatible, there is every indication that A. aculeata bears a mixed reproductive system, with a predominance of outcrossing. Given the genetic structure revealed hereby, future conservation strategies and germplasm collecting should be focussed on sampling and preserving individuals from different clusters. 相似文献
29.
Degradation of extracellular matrix by mouse trophoblast outgrowths: a model for implantation 总被引:1,自引:6,他引:1 下载免费PDF全文
During implantation the embryo attaches to the endometrial surface and trophoblast traverses the uterine epithelium, anchoring in the uterine connective tissue. To determine whether trophoblast can facilitate invasion of the uterus by degrading components of normal uterine extracellular matrix, mouse blastocysts were cultured on a radio-labeled extracellular matrix that contained glycoproteins, elastin, and collagen. The embryos attached to the matrix, and trophoblast spread over the surface. Starting on day 5 of culture there was a release of labeled peptides into the medium. The radioactive peptides released from the matrix by the embryos had molecular weights ranging from more than 25,000 to more than 200. By day 7 there were areas where individual trophoblast cells had separated from one another, revealing the underlying substratum that was cleared of matrix. When trophoblast cells were lysed with NH(4)OH on day 8, it was apparent that the area underneath the trophoblast outgrowth had been cleared of matrix. Scanning electron microscopy and time-lapse cinemicrography confirmed that the digestion of matrix was highly localized, taking place only underneath the trophoblast, with no evidence of digestion of the matrix beyond the periphery of the trophoblast outgrowth. The sharp boundaries of degredation observed may be due to localized proteinase secretion by trophoblast, to membrane proteinases on the surface of trophoblast, or to endocytosis. Digestion of the matrix was not dependent on plasminogen, thus ruling out a role for plasminogen activator. Digestion was not inhibited by a variety of hormones and inhibitors, including progesterone, 17β-estradiol, leupeptin, EDTA, colchicine, NH(4)Cl, or ε-aminocaproic acid. This system of culturing embryos on extracellular matrix may be useful in determining the processes that regulate trophoblast migration and invasion into the maternal tissues during implantation.0 相似文献
30.
Timothy?RH?RegnaultEmail author Hutton?V?Oddy Colin?Nancarrow Nadarajah?Sriskandarajah Rex?J?Scaramuzzi 《Reproductive biology and endocrinology : RB&E》2004,2(1):64