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131.
精子介导鱼类基因转移和聚合酶链反应检测技术 总被引:18,自引:0,他引:18
金鱼精子与美洲大绵wei的抗冻蛋白基因一起保温30分钟后,再与卵子受精,共获得145尾成鱼和若干胚胎。从胚胎和成鱼中提取DNA经聚合酶链反应(PCR法)扩增和Southern blot分子杂交表明,外源的抗冻蛋白基因进入了部分受体鱼的染色体组内。测定了45尾一年龄实验鱼中,有12尾显示出明确的杂交带,阳性率为26%。 相似文献
132.
The dynamic pressure method (DPM) is used for measurement of k(L)a in a 1-m(3) pilot scale fermentor in coalescing (distilled water) and noncoalescing (0.3 M Na(2)SO(4) aqueous solution) batches. The method consists in recording oxygen concentration in a batch after a small pressure change (20 kPa) in the fermentor. The upward pressure change is brought about by temporary closing and subsequent throttling of outlet gas stream and the downward change by full reopening of the gas outlet. Absorption of pure oxygen yields the same k(L)a values as absorption of air. In noncoalescing batch, the downward k(L)a values are always higher than the upward values owing to spontaneous nucleation of bubbles. The experiments performed in a stirred cell confirm this behavior. Thus, only upward pressure change should be used for measurement. The correlation of k(L)a data measured in small (18-L) and large (1000-L) vessels based on power dissipated and superficial gas velocity are in a good agreement. Unlike the DPM, the classical dynamic methods yield, under the same conditions, excessively low values of k(L)a (the dynamic startup method) or fail to produce data at all (the dynamic method with interchange of air for N(2)). (c) 1994 John Wiley & Sons, Inc. 相似文献
133.
The influence of short draft tubes covered by perforated plates on gas-liquid mass transfer was examined in external-loop airlift bioreactors. The volumetric mass transfer coefficients in a model external-loop airlift bioreactor were measured with water and non-Newtonian media. It was found that introduction of draft tubes covered with perforated plates in the riser significantly improved the mass transfer rate, particularly in higher viscous non-Newtonian fermentation media. The enhancement of mass transfer rate might be due mainly to an increase in bubble coalescence and redispersion. (c) 1994 John Wiley & Sons, Inc. 相似文献
134.
P. D. Chen H. Tsujimoto B. S. Gill 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,88(1):97-101
Diploid-like chromosome pairing in polyploid wheat is controlled by several Ph (pairing homoeologous) genes with major and minor effects. Homoeologous pairing occurs in either the absence of these genes or their inhibition by genes from other species (Ph
I genes). We transferred Ph
I genes from Triticum speltoides (syn Aegilops speltoides) to T. aestivum, and on the basis of further analysis it appears that two duplicate and independent Ph
I genes were transferred. Since Ph
I genes are epistatic to the Ph genes of wheat, homoeologous pairing between the wheat and alien chromosomes occurs in the F1 hybrids. Using the Ph
I gene stock, we could demonstrate homoeologous pairing between the wheat and Haynaldia villosa chromosomes. Since homoeologous pairing occurs in F1 hybrids and no cytogenetic manipulation is needed, the Ph
I gene stock may be a versatile tool for effecting rapid and efficient alien genetic transfers to wheat.Contribution no. 93-435-J from the Kansas Agricultural Experiment Station, Kansas State University, Manhattan, KS 66506-5502, USA 相似文献
135.
Vladimir A. Shuvalov 《Journal of bioenergetics and biomembranes》1994,26(6):619-626
A review of a recent study of the spectral and thermodynamic properties of cytochrome b559 as well as of the electron transfer between b559 and photosystem II reaction center cofactors in isolated D1/D2/cytochrome b559 complex RC-2 is presented. Attention is paid to the existence of intermediary-potential (IP, +150 mV) and extra-low-potential (XLP, –45 mV) hemes located close to the acceptor (quinone) and donor (P680) sides of the reaction center cofactors, respectively. These hemes found in isolated RC-2 probably correspond to the high-potential and low-potential hemes in chloroplasts, respectively. The above location of the hemes is believed to allow the photoreduction of the XLP heme and photooxidation of the IP heme. The electron transfer between the two hemes is discussed in terms of the cyclic electron flow and possible involvement in water splitting. 相似文献
136.
Zagrodzki Paweł Mietelski Jerzy W. Krośniak Mirosław Petelenz Barbara 《Biological trace element research》1994,(1):273-277
The aim of this work was to check whether the stable cesium content in forest litter affects the value of radiocesium from
litter-to-mushroom transfer factorTf or not. Total cesium in litter, measured by AAS, varied from 0.1–2.7 μg/g. These data, combined with earlier results for
mushrooms, showed no simple correlation forTf. More complex relationships provided very high correlation coefficients, but their validity needs further investigation. 相似文献
137.
Incubation of thylakoid membranes from spinach with low concentrations of mercuric chloride induces the loss of one of the iron-sulfur centers, FB, in Photosystem I (PS I) and inhibits the electron transfer from PS I to the soluble electron carrier, ferredoxin. Reconstitution of this damaged iron-sulfur center has been carried out by incubating treated thylakoid membranes with exogenous FeCl3 and Na2S in the presence of-mercaptoethanol under anaerobic conditions. Low temperature EPR measurements indicate that center FB is largely restored. Kinetic experiments show that the restored FB can be photoreduced from P700. However, these reconstituted thylakoid membranes are still incompetent in the photoreduction of ferredoxin and NADP+, even though ferredoxin binding to the modified membranes was not impaired, indicating additional changes in the structure of the PS I complex must have occurred. 相似文献
138.
Abstract: Changes of the main hydrodynamic and oxygen transfer parameters during Aspergillus niger cultivation in an external-loop air-lift bioreactor of 200 dm3 operating capacity were investigated. The final average concentrations of biomass and citric acid obtained in batch fermentations were about 17 g 1-1 and 90 g 1-1 , respectively. Significant influence of the increasing biomass concentration on the rheological properties of the broth and operating parameters was found. Volumetric oxygen transfer coefficient. k L a , was found to be dependent on the apparent viscosity of the broth with an exponent of -0.984. 相似文献
139.
Alexander N. Glazer Yvonne M. Gindt Crystal F. Chan Kenneth Sauer 《Photosynthesis research》1994,40(2):167-173
Efficient production of ATP and NADPH by the light reactions of oxygen-evolving photosynthesis demands continuous adjustment of transfer of absorbed light energy from antenna complexes to Photosystem I (PS I) and II (PS II) reaction center complexes in response to changes in light quality. Treatment of intact cyanobacterial cells with N-ethylmaleimide appears to disrupt energy transfer from phycobilisomes to Photosystem I (PS I). Energy transfer from phycobilisomes to Photosystem II (PS II) is unperturbed. Spectroscopic analysis indicates that the individual complexes (phycobilisomes, PS II, PS I) remain functionally intact under these conditions. The results are consistent with the presence of connections between phycobiliproteins and both PS II and PS I, but they do not support the existence of direct contacts between the two photosystems.Abbreviations Chl
chlorophyll
- EPR
electron paramagnetic resonance
- NEM
N-ethylmaleimide
- PBS
phycobilisome
- PS
photosystem 相似文献
140.
Anneli Ritala Kristian Aspegren Ulrika Kurtén Marjatta Salmenkallio-Marttila Leena Mannonen Riitta Hannus Veli Kauppinen Teemu H. Teeri Tor-Magnus Enari 《Plant molecular biology》1994,24(2):317-325
Transgenic, fertile barley (Hordeum vulgare L.) from the Finnish elite cultivar Kymppi was obtained by particle bombardment of immature embryos. Immature embryos were bombarded to the embryonic axis side and grown to plants without selection. Neomycin phosphotransferase II (NPTII) activity was screened in small plantlets. One out of a total of 227 plants expressed the transferred nptII gene. This plant has until now produced 98 fertile spikes (T0), and four of the 90 T0 spikes analyzed to date contained the nptII gene. These shoots were further analyzed and they expressed the transferred gene. From green grains, embryos were isolated and grown to plantlets (T1). The four transgenic shoots of Toivo (the T0 plant) produced 25 plantlets as T1 progeny. Altogether fifteen of these T1 plants carried the transferred nptII gene as detected with the PCR technique, fourteen of which expressed the nptII gene. The integration and inheritance of the transferred nptII gene was confirmed by Southern blot hybridization. Although present as several copies, the transferred gene was inherited as a single Mendelian locus into the T2 progeny. 相似文献