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71.
Z Zhong A Toukdarian D Helinski V Knauf S Sykes J E Wilkinson C O'Bryne T Shea C DeLoughery R Caspi 《Applied and environmental microbiology》2001,67(12):5771-5779
An agar-degrading marine bacterium identified as a Microscilla species was isolated from coastal California marine sediment. This organism harbored a single 101-kb circular DNA plasmid designated pSD15. The complete nucleotide sequence of pSD15 was obtained, and sequence analysis indicated a number of genes putatively encoding a variety of enzymes involved in polysaccharide utilization. The most striking feature was the occurrence of five putative agarase genes. Loss of the plasmid, which occurred at a surprisingly high frequency, was associated with loss of agarase activity, supporting the sequence analysis results. 相似文献
72.
Grape thaumatin-like proteins (TLPs) play roles in plant-pathogen interactions and can cause protein haze in white wine unless removed prior to bottling. Different isoforms of TLPs have different hazing potential and aggregation behavior. Here we present the elucidation of the molecular structures of three grape TLPs that display different hazing potential. The three TLPs have very similar structures despite belonging to two different classes (F2/4JRU is a thaumatin-like protein while I/4L5H and H2/4MBT are VVTL1), and having different unfolding temperatures (56 vs. 62°C), with protein F2/4JRU being heat unstable and forming haze, while I/4L5H does not. These differences in properties are attributable to the conformation of a single loop and the amino acid composition of its flanking regions. 相似文献
73.
Tomohiro Hamasaki Takahiro Matsumoto Naoya Sakamoto Akiko Shimahara Shiori Kato Ayumi Yoshitake Ayumi Utsunomiya Hisayoshi Yurimoto Esteban C. Gabazza Tadaaki Ohgi 《Nucleic acids research》2013,41(12):e126
Radioisotopes and fluorescent compounds are frequently used for RNA labeling but are unsuitable for clinical studies of RNA drugs because of the risk from radiation exposure or the nonequivalence arising from covalently attached fluorophores. Here, we report a practical phosphoramidite solid-phase synthesis of 18O-labeled RNA that avoids these disadvantages, and we demonstrate its application to quantification and imaging. The synthesis involves the introduction of a nonbridging 18O atom into the phosphate group during the oxidation step of the synthetic cycle by using 18O water as the oxygen donor. The 18O label in the RNA was stable at pH 3–8.5, while the physicochemical and biological properties of labeled and unlabeled short interfering RNA were indistinguishable by circular dichroism, melting temperature and RNA-interference activity. The 18O/16O ratio as measured by isotope ratio mass spectrometry increased linearly with the concentration of 18O-labeled RNA, and this technique was used to determine the blood concentration of 18O-labeled RNA after administration to mice. 18O-labeled RNA transfected into human A549 cells was visualized by isotope microscopy. The RNA was observed in foci in the cytoplasm around the nucleus, presumably corresponding to endosomes. These methodologies may be useful for kinetic and cellular-localization studies of RNA in basic and pharmaceutical studies. 相似文献
74.
Savignin, a potent thrombin inhibitor isolated from the salivary glands of the tick Ornithodoros savignyi (Acari: Argasidae). 总被引:4,自引:0,他引:4
A thrombin (E.C. 3.4.21.5) inhibitor, savignin, was isolated from the salivary glands of Ornithodoros savignyi by a combination of size exclusion, anion-exchange, and reversed-phase chromatography. The inhibitor has a molecular mass of 12,430.4 Da as determined by electrospray mass spectrometry. The behavior of savignin during anion-exchange chromatography indicated that it has an acidic pI. The available N-terminal sequence (residues 1-11) differed from that of ornithodorin with only one residue. Savignin inhibits thrombin-induced platelet aggregation, but has no effect on ADP- or collagen-induced aggregation. Kinetic studies indicated that savignin is a competitive, slow-, tight-binding inhibitor of alpha-thrombin (K(i) = 4.89 +/- 1.39 pM). Tight-binding kinetics showed that the inhibitor has a lower affinity for gamma-thrombin (K(i) = 22.3 +/- 5.9 nM). Plasmin, factor Xa, and trypsin are not inhibited by savignin. 相似文献
75.
D S Faffe G H Silva P M Kurtz E M Negri V L Capelozzi P R Rocco W A Zin 《Journal of applied physiology》2001,90(4):1400-1406
The dynamic mechanical properties of lung tissue and its contents of collagen and elastic fibers were studied in strips prepared from mice instilled intratracheally with saline (C) or silica [15 (S15) and 30 days (S30) after instillation]. Resistance, elastance, and hysteresivity were studied during oscillations at different frequencies on S15 and S30. Elastance increased from C to silica groups but was similar between S15 and S30. Resistance was augmented from C to S15 and S30 and was greater in S30 than in S15 at higher frequencies. Hysteresivity was higher in S30 than in C and S15. Silica groups presented a greater amount of collagen than did C. Elastic fiber content increased progressively along time. This increment was related to the higher amount of oxytalan fibers at 15 and 30 days, whereas elaunin and fully developed elastic fibers were augmented only at 30 days. Silicosis led not only to pulmonary fibrosis but also to fibroelastosis, thus assigning a major role to the elastic system in the silicotic lung. 相似文献
76.
Disseminated nocardiosis in three macaque monkeys 总被引:1,自引:0,他引:1
Extrapulmonary nocardiosis was diagnosed at necropsy in two rhesus monkeys (Macaca mulatta) and one pigtailed monkey (M. nemestrina) over a four-year period in a large primate center. Typical lesions were multiple pyogranulomatous foci in the liver, intestines, peritoneum, lung and brain. Partially acid-fast, branching, filamentous organisms were seen in all lesions. Nocardia sp. was isolated from two cases. We postulate that two of the monkeys were infected by the oral route because of the distribution of lesions. 相似文献
77.
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80.
The marine bacteriumVibrio anguillarum causes disease in fish worldwide and is particularly devastating in aquaculture. Little is known about the ecology ofV. anguillarum in the environment and how this may relate to the pathogenicity of this organism. Combining membrane filtration and a species-specific DNA probe, culturableV. anguillarum cells were detected in water from three habitats and in chinook salmon (Onchorynchus tshawytscha) tissue samples. Results show that different marine habitats have a marked effect on cell numbers and that water temperature may play a role in the culturability and distribution ofV. anguillarum. Vibrio anguillarum was detected from the gills of salmon within 24 h of transfer of fingerlings from freshwater to seawater, with cell numbers reaching a concentration of 1.9 × 102 cells g–1 tissue 28 days post transfer.Vibrio anguillarum cell numbers were low in the colon throughout the study, andV. anguillarum was not detected in healthy kidney samples. The methodology reported in this paper allows the accurate quantification of culturableV. anguillarum cells and has allowed a preliminary study of the ecology of this species. 相似文献