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排序方式: 共有249条查询结果,搜索用时 15 毫秒
1.
Susanne?Abelin?T?rnblom Holger?Maul Aurelija?KlimaviciuteEmail author Robert?E?Garfield Birgitta?Bystr?m Anders?Malmstr?m Gunvor?Ekman-Ordeberg 《Reproductive biology and endocrinology : RB&E》2005,3(1):33
Background
Preterm birth is the primary cause of the neonatal mortality and morbidity. There will be no preterm birth without a cervical softening. Nitric oxide (NO) is shown to be a mediator of term cervical ripening. The aim of this study was to investigate mRNA expression of the three isomers of NO synthases (NOS) and to identify them by immunohistochemistry in the human cervix at preterm birth compared to term. 相似文献2.
A low pH method of liposome-membrane fusion (Schneider et al., 1980, Proc. Natl. Acad. Sci. U. S. A. 77:442) was used to enrich the mitochondrial inner membrane lipid bilayer 30-700% with exogenous phospholipid and cholesterol. By varying the phospholipid-to- cholesterol ratio of the liposomes it was possible to incorporate specific amounts of cholesterol (up to 44 mol %) into the inner membrane bilayer in a controlled fashion. The membrane surface area increased proportionally to the increase in total membrane bilayer lipid. Inner membrane enriched with phospholipid only, or with phospholipid plus cholesterol up to 20 mol %, showed randomly distributed intramembrane particles (integral proteins) in the membrane plane, and the average distance between intramembrane particles increased proportionally to the amount of newly incorporated lipid. Membranes containing between 20 and 27 mol % cholesterol exhibited small clusters of intramembrane particles while cholesterol contents above 27 mol % resulted in larger aggregations of intramembrane particles. In phospholipid-enriched membranes with randomly dispersed intramembrane particles, electron transfer activities from NADH- and succinate-dehydrogenase to cytochrome c decreased proportionally to the increase in distance between the particles. In contrast, these electron- transfer activities increased with decreasing distances between intramembrane particles brought about by cholesterol incorporation. These results indicate that (a) catalytically interacting redox components in the mitochondrial inner membrane such as the dehydrogenase complexes, ubiquinone, and heme proteins are independent, laterally diffusible components; (b) the average distance between these redox components is effected by the available surface area of the membrane lipid bilayer; and (c) the distance over which redox components diffuse before collision and electron transfer mediates the rate of such transfer. 相似文献
3.
4.
Murat Akkurt Leocir Welter Erika Maul Reinhard Töpfer Eva Zyprian 《Molecular breeding : new strategies in plant improvement》2007,19(2):103-111
Sequence-characterized amplified regions markers (SCARs) were developed from six randomly amplified polymorphic DNA (RAPD)
markers linked to the major QTL region for powdery mildew (Uncinula necator) resistance in a test population derived from the cross of grapevine cultivars “Regent” (resistant) × “Lemberger”(susceptible).
RAPD products were cloned and sequenced. Primer pairs with at least 21 nucleotides primer length were designed. All pairs
were tested in the F1 progeny of “Regent” × “Lemberger”. The SCAR primers resulted in the amplification of specific bands
of expected sizes and were tested in additional genetic resources of resistant and susceptible germplasm. All SCAR primer
pairs resulted in the amplification of specific fragments. Two of the SCAR markers named ScORA7-760 and ScORN3-R produced
amplification products predominantly in resistant individuals and were found to correlate to disease resistance. ScORA7-760,
in particular, is suitable for marker-assisted selection for powdery mildew resistance and to facilitate pyramiding powdery
mildew resistance genes from various sources. 相似文献
5.
6.
The relationship between microorganisms and birds has received increased attention recently. The state of knowledge of this
relationship, however, is based largely on examination of sick or dead birds, and knowledge of the prevalence and community
structure and function of microbes in healthy wild populations is limited. Using carbon substrate utilization profiles, microbial
communities were examined in 91 cloacal samples from 14 species within apparently healthy summer and winter passerine populations.
Within each season, gradient lengths and eigenvalues from ordination analyses suggested that many samples differed in their
carbon substrate utilization and several had very different communities. Cloacal microbe carbon utilization profiles were
distinguishable among host species, season-specific diet, and study site in the ordination analyses. However, these patterns
were only observed for the analysis of the summer data set. The results of this study support the idea that the avian host’s
microbial community, relative to carbon substrate utilization, is related to host diet. Previously, this pattern had only
been reported for potential pathogens isolated from the avian cloaca. Study site–specific patterns in the ordination analysis
suggest that environmental conditions at a particular study site may influence cloacal microbial communities in birds. Results
of this study indicate that examination of community-level physiological profiles may be a useful technique for distinguishing
among avian cloacal samples, similar to that already established for discriminating aqueous and soil samples. Future studies
that correlate microbe physiological profiles to condition-based indices of avian hosts may be most useful for eventually
using the profile as an indicator of environmental conditions experienced by hosts. 相似文献
7.
8.
Timothy M. Maul Drew D. Dudgeon Michael T. Beste Daniel A. Hammer John S. Lazo Flordeliza S. Villanueva William R. Wagner 《Biotechnology and bioengineering》2010,107(5):854-864
Diagnosis of cardiovascular disease is currently limited by the testing modality. Serum tests for biomarkers can provide quantification of severity but lack the ability to localize the source of the cardiovascular disease, while imaging technology such as angiography and ultrasound can only determine areas of reduced flow but not the severity of tissue ischemia. Targeted imaging with ultrasound contrast agents offers the ability to locally image as well as determine the degree of ischemia by utilizing agents that will cause the contrast agent to home to the affected tissue. Ultrasound molecular imaging via targeted microbubbles (MB) is currently limited by its sensitivity to molecular markers of disease relative to other techniques (e.g., radiolabeling). We hypothesize that computational modeling may provide a useful first approach to maximize microbubble binding by defining key parameters governing adhesion. Adhesive dynamics (AD) was used to simulate the fluid dynamic and stochastic molecular binding of microbubbles to inflamed endothelial cells. Sialyl LewisX (sLex), P‐selectin aptamer (PSA), and ICAM‐1 antibody (abICAM) were modeled as the targeting receptors on the microbubble surface in both single‐ and dual‐targeted arrangements. Microbubble properties (radius [Rc], kinetics [kf, kr], and densities of targeting receptors) and the physical environment (shear rate and target ligand densities) were modeled. The kinetics for sLex and PSA were measured with surface plasmon resonance. Rc, shear rate, and densities of sLex, PSA, or abICAM were varied independently to assess model sensitivity. Firm adhesion was defined as MB velocity <2% of the free stream velocity. AD simulations revealed an optimal microbubble radius of 1–2 µm and thresholds for (>102 s?1) and (<10?3 s?1) for firm adhesion in a multi‐targeted system. State diagrams for multi‐targeted microbubbles suggest sLex and abICAM microbubbles may require 10‐fold more ligand to achieve firm adhesion at higher shear rates than sLex and PSA microbubbles. The AD model gives useful insight into the key parameters for stable microbubble binding, and may allow flexible, prospective design, and optimization of microbubbles to enhance clinical translation of ultrasound molecular imaging. Biotechnol. Bioeng. 2010;107: 854–864. © 2010 Wiley Periodicals, Inc. 相似文献
9.
M Matsuda A Tazumi S Kagawa T Sekizuka O Murayama JE Moore BC Millar 《BMC veterinary research》2006,2(1):1-4
Background
At present, six accessible sequences of 16S rDNA from Taylorella equigenitalis (T. equigenitalis) are available, whose sequence differences occur at a few nucleotide positions. Thus it is important to determine these sequences from additional strains in other countries, if possible, in order to clarify any anomalies regarding 16S rDNA sequence heterogeneity. Here, we clone and sequence the approximate full-length 16S rDNA from additional strains of T. equigenitalis isolated in Japan, Australia and France and compare these sequences to the existing published sequences.Results
Clarification of any anomalies regarding 16S rDNA sequence heterogeneity of T. equigenitalis was carried out. When cloning, sequencing and comparison of the approximate full-length 16S rDNA from 17 strains of T. equigenitalis isolated in Japan, Australia and France, nucleotide sequence differences were demonstrated at the six loci in the 1,469 nucleotide sequence. Moreover, 12 polymorphic sites occurred among 23 sequences of the 16S rDNA, including the six reference sequences.Conclusion
High sequence similarity (99.5% or more) was observed throughout, except from nucleotide positions 138 to 501 where substitutions and deletions were noted. 相似文献10.