排序方式: 共有19条查询结果,搜索用时 31 毫秒
1.
Occurrence of Bacillus subtilis with High Heat Resistance 总被引:4,自引:3,他引:1
2.
Purification and characterization of Dolichos lablab lectin 总被引:1,自引:0,他引:1
The mannose/glucose-binding Dolichos lablab lectin (designated DLL) has
been purified from seeds of Dolichos lablab (hyacinth bean) to
electrophoretic homogeneity by affinity chromatography on an ovalbumin-
Sepharose 4B column. The purified lectin gave a single symmetric protein
peak with an apparent molecular mass of 67 kDa on gel filtration
chromatography, and five bands ranging from 10 kDa to 22 kDa upon SDS-PAGE.
N-Terminal sequence analysis of these bands revealed subunit heterogeneity
due to posttranslational proteolytic truncation at different sites mostly
at the carboxyl terminus. The carbohydrate binding properties of the
purified lectin were investigated by three different approaches:
hemagglutination inhibition assay, quantitative precipitation inhibition
assay, and ELISA. On the basis of these studies, it is concluded that the
Dolichos lablab lectin has neither an extended carbohydrate combining site,
nor a hydrophobic binding site adjacent to it. The carbohydrate combining
site of DLL appears to most effectively accommodate a nonreducing terminal
alpha-d-mannosyl unit, and to be complementary to the C-3, C-4, and C-6
equatorial hydroxyl groups of alpha-d-mannopyranosyl and
alpha-d-glucopyranosyl residues. DLL strongly precipitates murine IgM but
not IgG, and the recent finding that this lectin interacts specifically
with NIH 3T3 fibroblasts transfected with the Flt3 tyrosine kinase receptor
and preserves human cord blood stem cells and progenitors in a quiescent
state for prolonged periods in culture, make this lectin a valuable tool in
biomedical research.
相似文献
3.
不同胁迫预处理提高水稻幼苗抗寒性期间蛋白质的变化 总被引:13,自引:0,他引:13
水稻(Oryza sativa L.)幼苗经盐、热激和冷三种不同胁迫预处理均提高了幼苗的抗寒性。与未预处理苗相比,在处理后、低温伤害后和常温下恢复2d的三个时期,不同胁迫预处理苗的可溶性和热不稳定蛋白含量变化趋势甚为相似,但热稳定蛋白含量变化则各有异同。SDS-PAGE图谱分析显示,不同胁迫预处理提高水稻幼苗抗寒性时,其可溶性蛋白、热稳定和热不稳定蛋白组成变化亦各有异同。除诱导出共有的新多肽外,还各自诱导出特有的新多肽。结果表明,植物对不同胁迫的交叉适应存在一定的共同机理,但亦可看出植物对同一种环境胁迫似乎不是以同一的机理去适应。 相似文献
4.
Emilia Grecka Malgorzata Statkiewicz Agnieszka Gorska Marzena Biernacka Monika Anna Grygorowicz Marek Masnyk Marek Chmielewski Katarzyna Gawarecka Tadeusz Chojnacki Ewa Swiezewska Maciej Malecki 《PloS one》2016,11(4)
PurposePrenyl ammonium iodides (Amino-Prenols, APs), semi-synthetic polyprenol derivatives were studied as prospective novel gene transfer agents.MethodsAP-7, -8, -11 and -15 (aminoprenols composed of 7, 8, 11 or 15 isoprene units, respectively) were examined for their capacity to form complexes with pDNA, for cytotoxicity and ability to transfect genes to cells.ResultsAll the carriers were able to complex DNA. The highest, comparable to commercial reagents, transfection efficiency was observed for AP-15. Simultaneously, AP-15 exhibited the lowest negative impact on cell viability and proliferation—considerably lower than that of commercial agents. AP-15/DOPE complexes were also efficient to introduce pDNA to cells, without much effect on cell viability. Transfection with AP-15/DOPE complexes influenced the expression of a very few among 44 tested genes involved in cellular lipid metabolism. Furthermore, complexes containing AP-15 and therapeutic plasmid, encoding the TIMP metallopeptidase inhibitor 2 (TIMP2), introduced the TIMP2 gene with high efficiency to B16-F10 melanoma cells but not to B16-F10 melanoma tumors in C57BL/6 mice, as confirmed by TIMP2 protein level determination.ConclusionObtained results indicate that APs have a potential as non-viral vectors for cell transfection. 相似文献
5.
6.
Stezhko VA Buglova EE Danilova LI Drozd VM Krysenko NA Lesnikova NR Minenko VF Ostapenko VA Petrenko SV Polyanskaya ON Rzheutski VA Tronko MD Bobylyova OO Bogdanova TI Ephstein OV Kairo IA Kostin OV Likhtarev IA Markov VV Oliynik VA Shpak VM Tereshchenko VP Zamotayeva GA Beebe GW Bouville AC Brill AB Burch JD Fink DJ Greenebaum E Howe GR Luckyanov NK Masnyk IJ McConnell RJ Robbins J Thomas TL Voillequé PG 《Radiation research》2004,161(4):481-492
The thyroid gland in children is one of the organs that is most sensitive to external exposure to X and gamma rays. However, data on the risk of thyroid cancer in children after exposure to radioactive iodines are sparse. The Chornobyl accident in Ukraine in 1986 led to the exposure of large populations to radioactive iodines, particularly (131)I. This paper describes an ongoing cohort study being conducted in Belarus and Ukraine that includes 25,161 subjects under the age of 18 years in 1986 who are being screened for thyroid diseases every 2 years. Individual thyroid doses are being estimated for all study subjects based on measurement of the radioactivity of the thyroid gland made in 1986 together with a radioecological model and interview data. Approximately 100 histologically confirmed thyroid cancers were detected as a consequence of the first round of screening. The data will enable fitting appropriate dose-response models, which are important in both radiation epidemiology and public health for prediction of risks from exposure to radioactive iodines from medical sources and any future nuclear accidents. Plans are to continue to follow-up the cohort for at least three screening cycles, which will lead to more precise estimates of risk. 相似文献
7.
In order to evaluate the impact of the lesser weever on the ecosystem of the southern North Sea, geographical distribution, density, growth, production and food requirements have been estimated. High densities were found on and around the Brown Ridge, an area with high tidal current velocities, medium grain-size of the sediment and a poor benthic fauna. Growth is restricted to the months of June October. During the winter cessation of growth a considerable loss of weight (about 20%) takes place. Mortality has been estimated by using the average size frequency distribution of all catches made from 1972 to 1984. The resulting convex type of survival curve indicates a high survival rate of the II to IV-group fishes. The production (estimated with Allen's graphical method) of a population of 100 individuals including all age groups (0-VI) amounts to 123.7 g AFDW-year'. In areas with highest densities, consequently, production amounts to 0.018–0.078 g AFDW-m2 -year-1 . With an assumed transfer efficiency of 10% through the year, food requirements amounts to 0.18–0.78 g AFDW-m 2 -year -1 . Since the lesser weever feeds mainly on fish (85.6%), almost exclusively on gobies (Pomatoschistus sp.), and with an assumed transfer efficiency of approximately 10%, the indirect predatory pressure exerted by it may amount to 1.6 6.7g AFDW-m 2 .year -1 . A possible feeding by gobies on pelagic organisms (calanoids, mysids) is discussed. 相似文献
8.
9.
This work presents results of methyl 7-oxoabiet-13(14)-en-18-oate ( 3 ) self-oxidation with air-oxygen in the presence of various bases such as triethylamine or sodium t-butoxide. While under aerobic conditions, the use of sodium t-butoxide as a base results in the formation of four isomeric alcohols, an addition of triethylamine into reaction medium directs the enone 3 oxidation to hydroperoxides. To clarify this base dependence and to obtain more in-depth information about this reaction additional studies with cyclohexenone as a reference enone have been undertaken. Their results demonstrated the predisposition of abietane hydroperoxides to oxidize α,β-unsaturated ketones to epoxides in the presence of t-butoxide while reducing the hydroperoxide group to hydroxyl. This ability of hydroperoxides to epoxidize conjugated double bonds and confirmed by the present study intermolecular course allowed proposing a plausible mechanism for this reaction. 相似文献
10.
Hexose-6-phosphate dehydrogenase (H6PDH-A2; beta-D-glucose:NAD(P)+
oxido-reductase; E.C. 1.1.1.47) of the teleost Fundulus heteroclitus (L.)
shows clinal allelic variation along the east coast of North America. Three
of the major allelic isozymes have been purified and compared for native
molecular weight, subunit molecular weight, isoelectric point, thermal
stability, and steady-state kinetic properties (pH 8.0 and 25 degrees C).
Significant differences were found among the allelic isozymes for
isoelectric point, thermal stability, and some kinetic parameters. The
predominant allelic isozyme in northern populations (H6PDH-AcAc) was found
to be more sensitive to heat denaturation than were the predominant
homozygous allelic isozymes isolated from southern populations (H6PDH-AaAa
and H6PDH-AbAb). The H6PDH-AcAc allelic isozyme had both a significantly
greater Km for glucose-6-phosphate than did either of the southern
phenotypes and a significantly greater Km for NADP+ and Ki of NAD+ than did
one of the southern phenotypes (H6PDH-AaAa). While the allelic isozymes are
functionally nonequivalent, it is not yet known whether these differences
are reflected at higher levels of biological organization.
相似文献