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131.
Isolation of a bacterial host selective for bacteriophage T4 containing cytosine in its DNA. 总被引:9,自引:5,他引:4 下载免费PDF全文
An Escherichia coli B strain, B834 galU56, has been isolated which supports growth of bacteriophage T4 with cytosine in its DNA while restricting growth of T4 with hydroxymethylcytosine. This host is partially deficient in uridine diphosphoglucose as determined by the ability of DNA isolated from T4 grown on it to accept glucose in an in vitro assay. In this mutant an intact rgl restriction system recognizes unglucosylated hydroxymethylcytosine residues in phage DNA, while the absence of a functional rB restriction function prevents degradation of unmodified DNA containing cytosine. 相似文献
132.
Undifferentiated callus derived from asparagus protoplast cultureshas been used for studies on organogenesis. Root and shoot formationhas been obtained with different hormonal balances. Adeninehas been found to be effective, together with a cytokinin, inpromoting the formation of somatic embryoids in this tissue. 相似文献
133.
The oligomerization of a family of four genetically clustered human gastrointestinal mucins 总被引:1,自引:0,他引:1
Mucins are synthesized and secreted by many epithelia. They are complex
glycoproteins that offer cytoprotection. In their functional configuration,
mucins form oligomers by a biosynthetic process that is poorly understood.
A family of four human gastrointestinal mucin genes (MUC2, MUC5AC, MUC5B,
and MUC6) is clustered to chromosome 11p15.5. To study oligomerization of
these related mucins, we performed metabolic labeling experiments with
[35S]amino acids in LS174T cells, and isolated mucin precursors by specific
immunoprecipitations that were analyzed on SDS-PAGE. Each of the precursors
of MUC2, MUC5AC, MUC5B, and MUC6 formed a single species of
disulfide-linked homo-oligomer within 1 h after pulse labeling. Based on
apparent molecular masses, these oligomeric precursors were most likely
dimers. Inhibition of vesicular RER-to-Golgi transport, with brefeldin A
and CCCP, did not affect the dimerization of MUC2 precursors, localizing
dimerization to the RER. O-Glycosylation of MUC2 followed dimerization.
Inhibition of N- glycosylation by tunicamycin retarded, but did not
inhibit, dimerization, indicating that N-glycans play a role in efficient
dimerization of MUC2 precursors. Based on sequence homology, the ability of
MUC2, MUC5AC, MUC5B and MUC6 to dimerize most likely resides in their
C-terminal domains. Thus, the RER-localized dimerization of secretory
mucins likely proceeds by similar mechanisms, which is an essential step in
the formation of the human gastrointestinal mucus- gels.
相似文献
134.
Used the random sampling and recommendation, 30 households of Mongolian in Horqin Juun Garon Country were selected to compare with 10 households of Han nationality which lives in the region of nearby. Forty sampling plots of homegardens were investigated. The results indicates that the perpendicular structure of homegarden plants in Mongolian and Han nationality can be classified to 0-1m, 1-2m, 2-5m, 5-10m, and higher than 10m. The perpendicular structure lower than 5m is predominance in both large and small homegardens. Comparing the cultivation pattern in two nationality, Mongolia still stay in the level of vegetable cultivation which relaled to the daily life, the plants for view and admire are very few at present. But Han nationality have started attaching importance to the view and admire homegarden plants. Besides, this research applied the software MVSP to analyze the type of homegardens and indacates that the homegarden of Mongolian in Horqin Juun Garon Country have four categories, and Han nationality have three categories. The results indicate that there are many differences between Mongolian and Han nationality. This is caused by the differences between the two nationalities in traditional farming culture, animal husbandry culture, the area of homegarden, the history of homegarden, the management of homegarden, and the traditional botanical knowledge on plant species utilization. 相似文献
135.
136.
NECATTN TÜRKMEN SALHA KIRICI MENURE ÖZGÜVEN MEMET NAN D. ALPASLAN KAYA 《Botanical journal of the Linnean Society. Linnean Society of London》2004,146(1):71-77
Plants traditionally used to dye carpets and woven matting in the eastern Mediterranean region were investigated. The survey was carried out in Kadirli, Feke, Aladağ, the surrounding villages of Adana, and in Osmaniye (Turkey). According to the survey results, 37 species of plants belonging to 29 families were used in natural dye production. The total dye contents of collected plants ranged from 1.5% to 10.0%. Mordants and dyes obtained from some of these plants were used to treat wool yarn and the yarn's dyed properties were tested. Some of the plants were also examined in terms of cultivation and fifteen were transferred to a Dye Plants Collection Garden. They were Alnus glutinosa (L.) Gaertn. ssp. antitaurica Yalt., Arctium minus ssp. pubens (Bab.) Arènes, Chrysanthemum segetum L., Cistus creticus L., Cotinus coggygria Scop., Datisca cannabina L., Galium verum ssp. glabrescens Ehrend., Isatis tinctoria ssp. tomentella (Boiss. & Balansa) P.H.Davis, Melissa officinalis ssp. inodora Bornm., Mentha longifolia (L.) Huds. ssp. longifolia , Reseda lutea var. lutea L., Rhamnus oleoides ssp. graecus (Boiss. & Reut.) Holmboe, Rhus coriaria L., Rubia tinctorum L., and Rumex patientia L. © 2004 The Linnean Society of London, Botanical Journal of the Linnean Society , 2004, 146 , 71–77. 相似文献
137.
S. B. HA S. B. LEE Y. LEE K. YANG N. LEE S. M. JANG J. S. CHUNG S. JUNG Y. S. KIM S. G. WI & K. BACK 《Plant, cell & environment》2004,27(1):79-88
Agrobacterium‐mediated gene transformation was used to introduce plastidic protoporphyrinogen IX oxidase (Protox) genes from Arabidopsis, with and without the transit sequence, into the rice genome. They were placed under the control of the constitutive and ubiquitous maize ubiquitin promoter, and their abilities to confer resistance to the diphenyl ether‐type herbicide, oxyfluorfen were compared. The integration and expression of the transgene in the T1 generation was examined by Southern, northern and western blot analyses. Surprisingly, as judged by an in vivo seed germination assay and an in vitro cellular leakage assay, both lines were similarly resistant to oxyfluorfen. The tolerance to cellular damage (lipid peroxidation and electrolyte leakage) was higher in transgenic plants than in wild‐type plants. In transgenic plants, the degree of herbicide resistance varied directly with the absolute amount of Protox protein expression. Both the intact protein and the protein with the transit sequence deleted were accumulated in plastids. 相似文献
138.
动物实验人员的素质是决定医院动物实验工作质量的重要因素.但通常被忽视。随着动物实验标准化进程的不断推进,提高动物实验工作人员的素质、增强专业技能就显得尤为重要。本文结合我院实践主要阐述综合性医院动物实验工作的特点、对动物实验工作人员基本素质的要求以及培养和提高的途径。 相似文献
139.
140.