首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 21 毫秒
1.
A set of modular binary vectors for transformation of cereals   总被引:2,自引:1,他引:1       下载免费PDF全文
Genetic transformation of crop plants offers the possibility of testing hypotheses about the function of individual genes as well as the exploitation of transgenes for targeted trait improvement. However, in most cereals, this option has long been compromised by tedious and low-efficiency transformation protocols, as well as by the lack of versatile vector systems. After having adopted and further improved the protocols for Agrobacterium-mediated stable transformation of barley (Hordeum vulgare) and wheat (Triticum aestivum), we now present a versatile set of binary vectors for transgene overexpression, as well as for gene silencing by double-stranded RNA interference. The vector set is offered with a series of functionally validated promoters and allows for rapid integration of the desired genes or gene fragments by GATEWAY-based recombination. Additional in-built flexibility lies in the choice of plant selectable markers, cassette orientation, and simple integration of further promoters to drive specific expression of genes of interest. Functionality of the cereal vector set has been demonstrated by transient as well as stable transformation experiments for transgene overexpression, as well as for targeted gene silencing in barley.  相似文献   

2.
Recent results suggest that the presence of common nitrogen salts (sodium nitrite and nitrate) in the irradiation medium can markedly protect filamentous blue green algae from potentially lethal ultraviolet light irradiation. Our results as well as general biological arguments as presented by Egami (above) support and extend Egami's original view that anaerobic respiratory pathways using nitrite and nitrate as terminal electron acceptors evolved prior to oxygen requiring aerobic respiratory pathways.  相似文献   

3.
近年来,通过阿米巴共培养等方法发现了一批新的病毒,统称为巨大病毒(giant virus)。它们分布广泛,不仅有很大的病毒颗粒,基因组也非常庞大,还编码许多与蛋白质合成相关的基因,突破了人们对病毒的一般认识,引发了对病毒起源和本质的讨论。巨大病毒被认为有潜在致病性。本文综述了在人体中针对两类最早发现的巨大病毒--拟菌病毒(Mimivirus)和马赛病毒(Marseillevirus)开展的血清学、分子生物学、宏基因组检测、病毒分离及其对哺乳动物感染和致病性研究的进展  相似文献   

4.
The use of Kdo thioglycosides as glycosyl donors using DMTST, IBr/AgOTf and NIS/AgOTf as promoters has been evaluated. Activation at low temperature allowed to escape the formation of 2,3-glycal byproducts to give glycosides in high yield and with good beta-anomeric selectivity. The use of diethyl ether as solvent and (especially) isopropylidene acetals as protecting groups improved the alpha-anomeric selectivity. NIS/AgOTf as promoter surprisingly yielded the 3-iodo-product via the glycal intermediate.  相似文献   

5.
The proteins belonging to different organisms as well as the natural amino acids as incorporated into proteins occurring free in tissues and lymphatic fluids are, as a rule, levorotatory. This article contains a simple explanation of this structural discrimination and of the extremely slow racemization of natural organic substances. Chirality 28:153–157, 2016. © 2015 Wiley Periodicals, Inc.  相似文献   

6.
Cyanobacteria (blue-green algae) are 02-evolving photosynthesizing prokaryotes that have an extensive history of use as a human food source and as a fertilizer in rice fields. They have also been recognized as an excellent source of vitamins and proteins and as such are found in health food stores in North America and elsewhere. Cyanobacteria have a great deal of potential as a source of fine chemicals, as a biofertilizer and as a source of renewable fuel. This potential is being realized as data from research in the areas of the physiology and chemistry of these organisms are gathered and as the knowledge of cyanobacterial genetics and genetic engineering increases. We review, here, the present (and possible future) uses of cyanobacteria and assess the state of the art with respect to the genetic manipulation of cyanobacteria.  相似文献   

7.
Recovery of Cell-Bound Interferon   总被引:5,自引:2,他引:3       下载免费PDF全文
Interferon could be recovered from homologous cells to which it was applied but could not be recovered from heterologous cells. The amount of interferon that could be recovered from cells corresponded to the sensitivity of the cells to the antiviral activity of the interferon: mouse embryo fibroblasts, which were 5 to 10 times as sensitive as L-929 cells to interferon, bound 5 to 10 times more interferon than the latter, whereas Lpa cells, which were only one-third as sensitive as L-929 cells to interferon, bound only one-third as much as the latter. The concentration of cell-bound interferon was as much as 150 times the extracellular concentration of interferon applied to the cells. Interferon bound to cells at 4 C with the same efficiency as it did to cells at 37 C, and actinomycin D-treated cells bound interferon as well as normal cells. Even though the total amount of interferon bound to cells was as much as 30% of the amount of interferon applied to them, no loss of antiviral activity was detectable from the medium.  相似文献   

8.
DNA has been found between bands, in puffs, and in RNA-rich lamellae of bands as dispersed DNA double helices coiled to form secondary helices with a diameter and period of about 400Å. In the bands and heterochromatic regions the secondary helix is further coiled or folded into compact masses. RNA-containing granules are present in interbands and RNA-rich lamellae as well as in puffs. The dispersed DNA of puffs, interbands and the RNA-rich lamellae of bands may all represent the part of the genome that is active in the salivary gland nucleus, while the compact DNA of bands as well as heterochromatic parts may comprise inactive genes.  相似文献   

9.
This paper reports the preliminary findings on the reproductive performance of 52 Bhotia women from the Mana Valley (Uttar Pradesh; elevation 10 560 ft.), who had approached menopause. The total amount of time available for reproduction and the total time used for effective reproduction as well as the period, which has been wasted as a result of sociocultural and biological factors, have been calculated. The total time available to Bhotia women for reproduction is found to be 1584 years, out of which 1563 years (98.67%) were used for effective reproduction. The reproductive wastage as a result of socio-economic and biological circumstances is calculated as 21 years only or 0.40 years per woman. All pregnancies as well as lactation operate to reduce fecundability. The various family limiting methods also lower the reproductive performance. A comparison has been made with the results of similar studies in other populations.  相似文献   

10.
Detached glandular trichome head preparations and epidermal strips with and without trichome heads were used to identify glandular trichome heads as the site of sucrose ester biosynthesis in tobacco. Carbon dioxide in solution as well as sucrose, glucose, and acetate were shown to serve as precursors to both sucrose esters and duvatrienediol diterpenes in detached trichome heads or epidermal strips, and gaseous CO2 was also efficiently utilized by epidermal strips. Thus, glandular heads can biosynthesize these principal exudate components from a molecule as simple as CO2. While formation of duvatriendiols from all precursors tested and conversion of sucrose and glucose to sucrose esters was light dependent, utilization of acetate to label the 6-O-acetyl group of the glucose moiety of sucrose esters occurred equally well in light and dark. The data suggest that CO2 and/or monosaccharides produced in trichome head cells and perhaps that supplied by other epidermal cells can act as carbon sources for sucrose ester and duvatrienediol biosynthesis which occurs in the glandular trichome head.  相似文献   

11.
Studies of L, D and DL-forms of glutamic acid as the sole nitrogen source or as a supplement to the major nitrogen source--ammonium sulphate have demonstrated that in the first case all forms of glutamic acid are assimilated by auxotrophic mutants--lysine producers. However, the lysine synthesis was very low, when L-glutamic acid was used as the only nitrogen source. Glutamic acid at a concentration of 0.01 M applied as a supplement to the major source of nitrogen acted as a stimulator of lysine synthesis, slightly inhibiting biomass increment. That was true of every form of glutamic acid, especially of DL-glutamic acid.  相似文献   

12.
张晓蓉 《微生物学报》2011,51(3):297-304
基于发展纳米材料"绿色合成技术"重要性,生物合成纳米材料已成为纳米合成技术研究热点。微生物具有廉价、易培养、繁殖快等优点被应用于多种纳米材料的生物合成研究,成为生物合成纳米材料的重要生物类群。本文综述了细菌、放线菌、酵母菌以及真菌等微生物应用于纳米生物合成技术的发展;着重评述了纳米材料微生物合成生物方法、纳米材料微生物合成相关机制、纳米材料形貌和尺寸微生物调控合成方法以及应用研究进展;并对纳米材料微生物合成技术未来发展趋势进行了展望。  相似文献   

13.
In this essay, based on qualitative research with Latino and Irish-American caregivers of demented elders, we argue that spatially and culturally constituted definitions of personhood, the moral life, and justice shape perceptions of normative aging, the agency of the demented persons and their place in the community, the appropriate care of the aged and demented, as well as partially determine the concrete resources which will be available to elders and their families. We review how ties to homelands and neighborhood institutions act as mediators and shapers of anticipatory grief, caregiver burdens, and caregiver resources, serving as a buffer against exhaustion and despair for some families (primarily the Irish-American sample), and as an additional site of loss or stress for others (primarily the Latino sample).  相似文献   

14.
Membrane preparations from Acer pseudoplatanus suspension cultures were demonstrated to incorporate radioactivity from GDP-[U-14C]mannose and UDP-N-acetyl-[6-(3)H]glucosamine into high-molecular-weight polymers characterized as glycoprotein. From 20 to 25% of the 14C was incorporated as fucose with the remainder as mannose, whereas 90% of the 3H was incorporated as N-acetylglucosamine with the remainder as N-acetylgalactosamine. Pronase digestion yielded radioactive glycopeptides that were separated into four fractions by gel-permeation chromatography and paper electrophoresis. The isolated glycopeptides differed in molecular weight and isotopes incorporated, as well as in amino-acid and monosaccharide composition. The membrane preparation also incorporated radioactivity from the added nucleotides into chloroform/methanol (2:1, v/v)- and chloroform/methanol/water (10:10:3, by vol.)-soluble lipids, and into an insoluble pellet.  相似文献   

15.
T Shikimi  T Kobayashi  K Hattori 《Enzyme》1979,24(5):348-352
Potassium thiocyanate inhibited the activities of trypsin and chymotrypsin. The inhibition was mixed type on both enzymes with casein as substrate and on trypsin with tosyl-L-arginine methyl ester as substrate, but was uncompetitive on chymotrypsin with benzoyl-L-tyrosine p-nitroanilide as substrate.  相似文献   

16.
In order to elucidate whitening mechanisms of arbutin (hydroquinone-O-beta-D-glucopyranoside), its effects on mushroom tyrosinase were analyzed by spectrophotometric, polarographic, and HPLC experiments. It was found that as soon as catalytic amounts of L-DOPA become available as a cofactor, arbutin acts as a monophenol substrate. A significant enzymatic product was identified as 3,4-dihydroxyphenyl-O-beta-D-glucopyranoside by NMR and MS experiments.  相似文献   

17.
The article presents some data on teaching Biochemistry at the Nature Department of Kharkiv Imperial University Physico-Mathematical Faculty, as well as restoration of biochemical education and scientific researches as a result of the University reorganization in the Soviet period and foundation of the Biochemistry Chair at the Biological Faculty in the renovated Kharkiv State University. The analysis of scientific biochemical investigations conducted in the Kharkiv University till now is revealed. The special attention is paid to development of such a scientific trend as age physiology and biochemistry. The article deals with the comprehensive information on scientific and pedagogical activity of the outstanding scientists such as O. V. Nagorny and I. M. Bulankin as founders of the Kharkiv school of age physiology and biochemistry. The work has utilized some archive data.  相似文献   

18.
This article investigates the ways in which a group of enthusiasts for London constitute their city. The 'personality' attributed to London is described, as well as the interpretive acts that reveal it. These people, who also lead walking tours across the city, privilege 'detail' as their term of analysis. The article examines the identified qualities of that category, in particular its perceived capacity to animate the plural time-spaces of the city. This sensitivity to detail is presented as part of a sensing of place, which allows people to regard themselves as uniquely able to see the city. The article is intended as a contribution to the ethnography of London.  相似文献   

19.
Nuclear magnetic resonance spectroscopy, fast-atom bombardment mass spectrometry, gas chromatography-mass spectrometry, as well as chemical degradations were used to elucidate the structure of the major glycolipids of Mycobacterium fortuitum. Three main glycoconjugates were detected and their structures established as 2,3-diacyl, 2,3,4- and 2,3,6-triacyl trehalose. The characteristic infrared spectrum which led to their original designation as mycoside F, a family of glycolipids limited in distribution to M. fortuitum, was due to the nature of the fatty acyl substiuents identified primarily as 2-methyl-octadecen-2-oyl. The antigenic glycolipids typified the biovar. fortuitum, thus allowing its easy recognition from the C-mycoside glycopeptidolipid-containing biovar. peregrinum.  相似文献   

20.
The degree of deacetylation (DDA) of chitosan determines the biopolymer's physico-chemical properties and technological applications. pH-Potentiometric titration seems to offer a simple and convenient means of determining DDA. However, to obtain accurate pH-potentiometric DDA values, several factors have to be taken into consideration. We found that the moisture content of the air-dry chitosan samples can be as high as 15%, and a reasonable fraction of this humidity cannot be removed by ordinary drying. Corrections have to be made for the ash content, as in some samples it can be as high as 1% by weight. The method of equivalence point determination was also found to cause systematic variations in the results and in some samples extra acid as high as 1 mol% of the free amino content was also identified. To compensate for the latter effect, the second equivalence point of the titration has to be determined separately and the analytical concentration of the acid be corrected for it. All the corrections listed here are necessary to obtain DDA values that are in reasonable agreement with those obtained from (1)H NMR and IR spectroscopic measurements. The need for these corrections severely limits the usefulness of pH-metry for determining accurate DDA values and thus potentiometry is hardly able to compete with other standard spectroscopic procedures, that is, (1)H NMR spectroscopy.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号