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排序方式: 共有69条查询结果,搜索用时 46 毫秒
41.
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43.
The taste of polycose in hamsters 总被引:2,自引:2,他引:0
Hamsters show a preference for Polycose, a mixture of starch-derived
glucose polymers, that is as strong as their preference for sucrose.
However, in the hamster, taste aversions to Polycose may be less easily
acquired than taste aversions to sucrose and the qualitative aspects of
Polycose are unknown in this species. In order to examine the taste of
Polycose in the hamster, we utilized a taste-aversion protocol with two
conditioning trials. Animals were trained to avoid one of three different
conditioning stimuli: 50 mM sucrose, 100 mM Polycose and a mixture of 50 mM
sucrose with 100 mM Polycose. Control animals were conditioned with
deionized water. After the second conditioning trial, generalization
testing began for the three conditioning stimuli plus 3 mM citric acid, 300
mM KCI and 30 mM NaCl. The results showed that aversions to Polycose,
sucrose or the Polycose/sucrose mixture cross- generalized, demonstrating
that Polycose and sucrose share a common taste percept in the hamster. None
of the aversions generalized to NaCl, citric acid or KCI. In addition,
comparisons among the patterns of taste generalizations indicated that the
tastes of Polycose and sucrose also had distinct qualitative components.
Finally, although the taste of 100 mM Polycose was more salient than the
taste of 50 mM sucrose, the taste of sucrose could still be detected in a
mixture with Polycose.
相似文献
44.
Purification of galectin-3 from ovine placenta: developmentally regulated expression and immunological relevance 总被引:1,自引:1,他引:1
Iglesias MM; Rabinovich GA; Ambrosio AL; Castagna LF; Sotomayor CE; Wolfenstein-Todel C 《Glycobiology》1998,8(1):59-65
Galectins, beta-galactoside-binding lectins, are extensively distributed in
the animal kingdom and share some basic molecular properties. Galectin-3, a
member of this family, is generally associated with differentiation,
morphogenesis, and metastasis. In this study, galectin-3 was isolated from
ovine placental cotyledons round the middle of the gestation period by
lactose extraction followed by affinity chromatography on lactosyl-agarose,
and separated from galectin-1 by size exclusion chromatography on a
Superose 12 column. Under native conditions this lectin behaved as a
monomer with an apparent molecular weight of approximately 29,000 and an
isoelectric point of 9.0. The partial amino acid sequence of the peptides
obtained by tryptic digestion of this protein followed by HPLC separation
showed striking homology with other members of the galectin-3 subfamily.
Furthermore, ovine placental galectin-3 exhibited specific mitogenic
activity toward rat spleen mononuclear cells. Besides, this protein
strongly reacted with a rabbit antiserum raised against a chicken galectin.
Results obtained by Western blot analysis showed that its expression was
greatly decreased in term placenta with respect to the middle of the
gestation period, suggesting a regulated expression throughout development.
相似文献
45.
Marvin Djukic Dominik Becker Anja Poehlein Sonja Voget Rolf Daniel 《Journal of bacteriology》2012,194(22):6365
Paenibacillus alvei is known as a secondary invader during European foulbrood of honeybees. Here, we announce the 6.83-Mb draft genome sequence of P. alvei type strain DSM 29. Putative genes encoding an antimicrobial peptide, a binary toxin, a mosquitocidal toxin, alveolysin, and different polyketides and nonribosomal peptides were identified. 相似文献
46.
47.
Vogel Rudi F Pavlovic Melanie Ehrmann Matthias A Wiezer Arnim Liesegang Heiko Offschanka Stefanie Voget Sonja Angelov Angel Bcker Georg Liebl Wolfgang 《Microbial cell factories》2011,10(1):1-11
Background
The Ala-Pro-rich O-glycoprotein known as the 45/47 kDa or APA antigen from Mycobacterium tuberculosis is an immunodominant adhesin restricted to mycobacterium genus and has been proposed as an alternative candidate to generate a new vaccine against tuberculosis or for diagnosis kits. In this work, the recombinant O-glycoprotein APA was produced by the non-pathogenic filamentous bacteria Streptomyces lividans, evaluating three different culture conditions. This strain is known for its ability to produce heterologous proteins in a shorter time compared to M. tuberculosis.Results
Three different shake flask geometries were used to provide different shear and oxygenation conditions; and the impact of those conditions on the morphology of S. lividans and the production of rAPA was characterized and evaluated. Small unbranched free filaments and mycelial clumps were found in baffled and coiled shake flasks, but one order of magnitude larger pellets were found in conventional shake flasks. The production of rAPA is around 3 times higher in small mycelia than in larger pellets, most probably due to difficulties in mass transfer inside pellets. Moreover, there are four putative sites of O-mannosylation in native APA, one of which is located at the carboxy-terminal region. The carbohydrate composition of this site was determined for rAPA by mass spectrometry analysis, and was found to contain different glycoforms depending on culture conditions. Up to two mannoses residues were found in cultures carried out in conventional shake flasks, and up to five mannoses residues were determined in coiled and baffled shake flasks.Conclusions
The shear and/or oxygenation parameters determine the bacterial morphology, the productivity, and the O-mannosylation of rAPA in S. lividans. As demonstrated here, culture conditions have to be carefully controlled in order to obtain recombinant O-glycosylated proteins with similar "quality" in bacteria, particularly, if the protein activity depends on the glycosylation pattern. Furthermore, it will be an interesting exercise to determine the effect of shear and oxygen in shake flasks, to obtain evidences that may be useful in scaling-up these processes to bioreactors. Another approach will be using lab-scale bioreactors under well-controlled conditions, and study the impact of those on rAPA productivity and quality. 相似文献48.
黄檗丛枝菌根真菌鉴定 总被引:1,自引:0,他引:1
目的:利用形态学特征与Nested-PCR技术鉴定黄檗丛枝菌根真菌。方法:采用酸性品红染色法挑选黄檗丛枝菌根。同时,利用湿筛法获得AM真菌孢子,进行形态学鉴定。运用Nested-PCR技术,对黄檗粗提DNA进行特异性扩增,采用blastn进行序列相似性比较。并构建系统进化树,确定侵染黄檗根系的AM真菌。结果:编号为HDAM-1的AM真菌孢子,形态特征与G.intraradices的特征描述一致。Nested-PCR检测到约455bp的目的片段,其序列与G.intraradices(DQ469118)相似性最高,达97.8%,有11个碱基的差异。系统进化树显示该序列在基于25S rDNA的进化树中与G.intraradices(DQ469118.1)处于同一分支,确定G.intraradices侵染黄檗根系。结论:将形态学特征与Nested-PCR技术相结合鉴定AM真菌,不仅简易、经济,而且能够提高研究结果的可靠性。 相似文献
49.
Marjolijn CE Bragt Jogchum Plat Marco Mensink Patrick Schrauwen Ronald P Mensink 《BMC endocrine disorders》2009,9(1):1-9
Background
The aim of this study is to perform a cost-effectiveness comparison between palpation-guided thyroid fine-needle aspiration biopsies (P-FNA) and ultrasound-guided thyroid FNA biopsies (USG-FNA).Methods
Each nodule was considered as a case. Diagnostic steps were history and physical examination, TSH measurement, Tc99m thyroid scintigraphy for nodules with a low TSH level, initial P-FNA versus initial USG-FNA, repeat USG-FNA for nodules with initial inadequate P-FNA or USG-FNA, hemithyroidectomy for inadequate repeat USG-FNA. American Thyroid Association thyroid nodule management guidelines were simulated in estimating the cost of P-FNA strategy. American Association of Clinical Endocrinologists guidelines were simulated for USG-FNA strategy. Total costs were estimated by adding the cost of each diagnostic step to reach a diagnosis for 100 nodules. Strategy cost was found by dividing the total cost to 100. Incremental cost-effectiveness ratio (ICER) was calculated by dividing the difference between strategy cost of USG-FNA and P-FNA to the difference between accuracy of USG-FNA and P-FNA. A positive ICER indicates more and a negative ICER indicates less expense to achieve one more additional accurate diagnosis of thyroid cancer for USG-FNA.Results
Seventy-eight P-FNAs and 190 USG-FNAs were performed between April 2003 and May 2008. There were no differences in age, gender, thyroid function, frequency of multinodular goiter, nodule location and diameter (median nodule diameter: 18.4 mm in P-FNA and 17.0 mm in USG-FNA) between groups. Cytology results in P-FNA versus USG-FNA groups were as follows: benign 49% versus 62% (p = 0.04), inadequate 42% versus 29% (p = 0.03), malignant 3% (p = 1.00) and indeterminate 6% (p = 0.78) for both. Eleven nodules from P-FNA and 18 from USG-FNA group underwent surgery. The accuracy of P-FNA was 0.64 and USG-FNA 0.72. Unit cost of P-FNA was 148 Euros and USG-FNA 226 Euros. The cost of P-FNA strategy was 534 Euros and USG-FNA strategy 523 Euros. Strategy cost includes the expense of repeat USG-FNA for initial inadequate FNAs and surgery for repeat inadequate USG-FNAs. ICER was -138 Euros.Conclusion
Universal application of USG-FNA for all thyroid nodules is cost-effective and saves 138 Euros per additional accurate diagnosis of benign versus malignant thyroid nodular disease.Trial registration
ClinicalTrials.gov, NCT00571090 相似文献50.
Summary The use of apple pomace for butanol production was studied by employing strains ofClostridium acetobutylicum andbutylicum. Yields of butanol between 1.9 and 2.2 % of fresh apple pomace are reported. 相似文献