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21.
Sugiyama M Suzuki S Tonouchi N Yokozeki K 《Bioscience, biotechnology, and biochemistry》2003,67(12):2524-2532
Xylitol production from D-arabitol by the membrane and soluble fractions of Gluconobacter oxydans was investigated. Two proteins in the soluble fraction were found to have the ability to increase xylitol production. Both of these xylitol-increasing factors were purified, and on the basis of their NH(2)-terminal amino acid sequences the genes encoding both of the factors were cloned. Expression of the cloned genes in Escherichia coli showed that one of the xylitol-increasing factors is the bifunctional enzyme transaldolase/glucose-6-phosphate isomerase, and the other is ribulokinase. Using membrane and soluble fractions of G. oxydans, 3.8 g/l of xylitol were produced from 10 g/l D-arabitol after incubation for 40 h, and addition of purified recombinant transaldolase/glucose-6-phosphate isomerase or ribulokinase increased xylitol to 5.4 g/l respectively, confirming the identity of the xylitol-increasing factors. 相似文献
22.
Nozaki H Suzuki S Tsuyoshi N Yokozeki K 《Bioscience, biotechnology, and biochemistry》2003,67(9):1923-1929
A potent producer of D-arabitol was isolated by screening of natural sources and identified as Metschnikowia reukaufii AJ14787. Resting cells of this strain can efficiently produce D-arabitol from D-glucose with a weight yield of more than 60%, and can also produce D-arabitol from several other types of sugars such as polyols, ketoses, and aldoses. To improve productivity, various culture conditions such as temperature and the concentrations of D-glucose and nitrogen sources were examined. Under optimal conditions, 206 g/l of D-arabitol was produced from D-glucose with a weight yield of 52% in 100 hours. 相似文献
23.
Theonellamide A, a bicyclic peptide isolated from a Theonella sponge, was fixed on hydrazide-containing gel beads and screened for its binding proteins from rabbit liver tissues. Analysis
by sodium dodecyl sulfate–polyacrylamide gel electrophoresis revealed that two major proteins of 80 kDa and 55 kDa interacted
with theonellamide A. The interaction between theonellamide A and two proteins was confirmed by competition experiments in
which these two proteins failed to bind to theonellamide A–conjugated gel beads in the presence of theonellamide A or F. Amino-terminal
amino acid sequence analysis of peptide fragments derived from the binding proteins by lysylendopeptidase digestion demonstrated
that the 80-kDa and 55-kDa proteins were 17β-hydroxysteroid dehydrogenase IV and glutamate dehydrogenase, respectively. In
an in vitro assay system, amination of α-ketoglutarate by glutamate dehydrogenase was activated with theonellamide F, although
this effect was weaker than that with adenosine diphosphate, a well-known activator.
Received October 15, 1999; accepted January 4, 2000. 相似文献
24.
Ryutaro Kakinuma Noriyuki Moriyama Yukio Muramatsu Shiho Gomi Masahiro Suzuki Hirobumi Nagasawa Masahiko Kusumoto Tomohiko Aso Yoshihisa Muramatsu Takaaki Tsuchida Koji Tsuta Akiko Miyagi Maeshima Naobumi Tochigi Shun-ichi Watanabe Naoki Sugihara Shinsuke Tsukagoshi Yasuo Saito Masahiro Kazama Kazuto Ashizawa Kazuo Awai Osamu Honda Hiroyuki Ishikawa Naoya Koizumi Daisuke Komoto Hiroshi Moriya Seitaro Oda Yasuji Oshiro Masahiro Yanagawa Noriyuki Tomiyama Hisao Asamura 《PloS one》2015,10(12)
25.
Yosuke?Shida Kaori?Yamaguchi Mikiko?Nitta Ayana?Nakamura Machiko?Takahashi Shun-ichi?Kidokoro Kazuki?Mori Kosuke?Tashiro Satoru?Kuhara Tomohiko?Matsuzawa Katsuro?Yaoi Yasumitsu?Sakamoto Nobutada?Tanaka Yasushi?Morikawa Wataru?OgasawaraEmail author 《Biotechnology for biofuels》2015,8(1):230
Background
The filamentous fungus Trichoderma reesei (anamorph of Hypocrea jecorina) produces increased cellulase expression when grown on cellulose or its derivatives as a sole carbon source. It has been believed that β-glucosidases of T. reesei not only metabolize cellobiose but also contribute in the production of inducers of cellulase gene expression by their transglycosylation activity. The cellulase hyper-producing mutant PC-3-7 developed in Japan has enhanced cellulase production ability when cellobiose is used as the inducer. The comparative genomics analysis of PC-3-7 and its parent revealed a single-nucleotide mutation within the bgl2 gene encoding intracellular β-glucosidase II (BGLII/Cel1a), giving rise to an amino acid substitution in PC-3-7, which could potentially account for the enhanced cellulase expression when these strains are cultivated on cellulose and cellobiose.Results
To analyze the effects of the BGLII mutation in cellulase induction, we constructed both a bgl2 revertant and a disruptant. Enzymatic analysis of the transformant lysates showed that the strain expressing mutant BGLII exhibited weakened cellobiose hydrolytic activity, but produced some transglycosylation products, suggesting that the SNP in bgl2 strongly diminished cellobiase activity, but did not result in complete loss of function of BGLII. The analysis of the recombinant BGLII revealed that transglycosylation products might be oligosaccharides, composed probably of glucose linked β-1,4, β-1,3, or a mixture of both. PC-3-7 revertants of bgl2 exhibited reduced expression and inducibility of cellulase during growth on cellulose and cellobiose substrates. Furthermore, the effect of this bgl2 mutation was reproduced in the common strain QM9414 in which the transformants showed cellulase production comparable to that of PC-3-7.Conclusion
We conclude that BGLII plays an important role in cellulase induction in T. reesei and that the bgl2 mutation in PC-3-7 brought about enhanced cellulase expression on cellobiose. The results of the investigation using PC-3-7 suggested that other mutation(s) in PC-3-7 could also contribute to cellulase induction. Further investigation is essential to unravel the mechanism responsible for cellulase induction in T. reesei.26.
Shunsuke Takahashi Tomohiro Usui Shohei Kawasaki Hidefumi Miyata Hirofumi Kurita Shun-ichi Matsuura Akira Mizuno Masahiko Oshige Shinji Katsura 《Analytical biochemistry》2014
T7 Exonuclease (T7 Exo) DNA digestion reactions were studied using direct single-molecule observations in microflow channels. DNA digestion reactions were directly observed by staining template DNA double-stranded regions with SYTOX Orange and staining single-stranded (digested) regions with a fluorescently labeled ssDNA-recognizing peptide (ssBP-488). Sequentially acquired photographs demonstrated that a double-stranded region monotonously shortened as a single-stranded region monotonously increased from the free end during a DNA digestion reaction. Furthermore, DNA digestion reactions were directly observed both under pulse-chase conditions and under continuous buffer flow conditions with T7 Exo. Under pulse-chase conditions, the double-stranded regions of λDNA monotonously shortened by a DNA digestion reaction with a single T7 Exo molecule, with an estimated average DNA digestion rate of 5.7 bases/s and a processivity of 6692 bases. Under continuous buffer flow conditions with T7 Exo, some pauses were observed during a DNA digestion reaction and double-stranded regions shortened linearly except during these pauses. The average DNA digestion rate was estimated to be 5.3 bases/s with a processivity of 5072 bases. Thus, the use of our direct single-molecule observations using a fluorescently labeled ssDNA-recognizing peptide (ssBP-488) was an effective analytic method for investigating DNA metabolic processes. 相似文献
27.
A simple molecular combing method for analysis of biochemical reactions, called the moving droplet method, has been developed. In this method, small droplets containing DNA molecules run down a sloped glass substrate, and this creates a moving interface among the air, droplet, and substrate that stretches the DNA molecules. This method requires a much smaller volume of sample solution than other established combing methods, allowing wider application in various fields. Using this method, λDNA molecules were stretched and absorbed to a glass substrate, and single-molecule analysis of DNA synthesis by DNA polymerases was performed. 相似文献
28.
Kongrit D Jisaka M Iwanaga C Yokomichi H Katsube T Nishimura K Nagaya T Yokota K 《Bioscience, biotechnology, and biochemistry》2007,71(2):491-498
A plant allene oxide synthase (AOS) reacting with 13S-hydroperoxy-9Z,11E,15Z-octadecatrienoic acid (13-HPOT), a lipoxygenase product of alpha-linolenic acid, provides an allene oxide which functions as an intermediate for jasmonic acid (JA) synthesis, making AOS a key enzyme regulating the JA level in plants. Although AOSs in various plants have been investigated, there is only limited information about AOSs in soybean (Glycine max). In this study, we cloned and characterized two soybean AOSs, GmAOS1 and GmAOS2, sharing 95% homology in the predicted amino acid sequences. GmAOS1 and GmAOS2 were composed of 564 and 559 amino acids respectively, with predicted N-terminal chloroplast-targeting signal peptides. Both AOSs expressed in Escherichia coli were selective for 13S-hydroperoxides of alpha-linolenic and linoleic acids, suggesting the potential of GmAOS1 and GmAOS2 to contribute to JA synthesis. GmAOS1 and GmAOS2 were expressed in leaves, stems, and roots, suggesting broad distribution in a soybean plant. 相似文献
29.
Chemoenzymatic syntheses of amylose-grafted chitin and chitosan 总被引:1,自引:0,他引:1
Amylose-grafted chitin and chitosan were synthesized by chemoenzymatic methods according to the following reaction manners. First, maltoheptaose was introduced to chitosan by a reductive amination using sodium cyanotrihydroborate in a mixed solvent of 1.0 mol/L aqueous acetic acid and methanol at room temperature to produce a maltoheptaose-grafted chitosan (1). The functionality of maltoheptaose to chitosan in 1 depended on reaction time. The phosphorylase-catalyzed enzymatic polymerization of R-D-glucose 1-phosphate was then performed from 1 to obtain amylose-grafted chitosan (2). Maltoheptaose-grafted chitin (3) was synthesized by N-acetylation of 1 using acetic anhydride in a mixed solvent of aqueous acetic acid and methanol. Then, synthesis of amylose-grafted chitin (4) was performed by the phosphorylase-catalyzed enzymatic polymerization under conditions the same as those for 2. The average DPs of amylose graft chains in 2 and 4 depended on the feed ratios of R-D-glucose 1-phosphate to maltoheptaose primers in 1 and 3. 相似文献
30.