全文获取类型
收费全文 | 74篇 |
免费 | 12篇 |
专业分类
86篇 |
出版年
2023年 | 1篇 |
2022年 | 1篇 |
2019年 | 4篇 |
2018年 | 1篇 |
2017年 | 1篇 |
2016年 | 1篇 |
2015年 | 3篇 |
2014年 | 1篇 |
2013年 | 1篇 |
2012年 | 7篇 |
2011年 | 2篇 |
2010年 | 3篇 |
2009年 | 3篇 |
2008年 | 7篇 |
2007年 | 3篇 |
2006年 | 4篇 |
2005年 | 7篇 |
2004年 | 2篇 |
2003年 | 7篇 |
2002年 | 5篇 |
2001年 | 4篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1994年 | 1篇 |
1993年 | 2篇 |
1992年 | 3篇 |
1991年 | 2篇 |
1989年 | 1篇 |
1988年 | 1篇 |
1987年 | 2篇 |
排序方式: 共有86条查询结果,搜索用时 13 毫秒
71.
E. M. J. Salentijn N. N. Sandal R. Klein-Lankhorst W. Lange Th. S. M. De Bock K. A. Marcker W. J. Stiekema 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1994,89(4):459-466
New members of a satellite DNA family (Sat 121), specific for wild beets of the section Procumbentes of the genus Beta, were isolated. Sequence analysis showed that the members of Sat-121 fall into two distinct classes. The organization of Sat-121 in the vicinity of a beet cyst nematode (Heterodera schachtii Schm.) resistance locus (Hs1) in B. patellaris and B. procumbens was investigated by pulsed-field gel electrophoresis (PFGE) using DNA from a series of resistant monosomic fragment additions, each containing an extra chromosome fragment of B. patellaris chromosome-1 (pat-1) in B. vulgaris. In this way several clusters of Sat-121 flanking the Hs1
pat-1
locus were identified. In nematode resistant diploid introgressions (2n=18), which contain small segments of B. procumbens chromosome-1 (pro-1) in B. vulgaris, only two major Sat-121 clusters were detected near the Hs1
pro-1
locus. 相似文献
72.
Yadav Mahendra Sharma Pooja Kushwah Himanshu Sandal Nidhi Chauhan Meenakshi Kanwar 《Journal of applied phycology》2022,34(1):363-373
Journal of Applied Phycology - Chlorella is a green alga consumed as a dietary food supplement in pulverized form. In addition to its high nutritional value, it is also reported as an excellent... 相似文献
73.
Masayoshi Kawaguchi Andrea Pedrosa-Harand Koji Yano Makoto Hayashi Yoshikatsu Murooka Katsuharu Saito Toshiyuki Nagata Kiyoshi Namai Hiroshi Nishida Daisuke Shibata Shusei Sato Satoshi Tabata Masaki Hayashi Kyuya Harada Niels Sandal Jens Stougaard Andreas Bachmair William F Grant 《DNA research》2005,12(1):69-77
In order to consolidate molecular genetic system in Lotus japonicus and to further access the biological diversity in Lotea, we introduce here Lotus burttii B-303 derived from West Pakistan as the third crossing partner of the Gifu ecotype (B-129-S9) for a genetic analysis. L. burttii is a relatively small and early flowering plant with non-shattering behavior. The general chromosome morphology is very similar to Gifu, and fluorescence in situ hybridization (FISH) analysis revealed that the short arm of chromosome 1 in L. burttii is comparable to that of Gifu, indicating that the translocation event involving chromosomes 1 and 2, which was observed in L. japonicus Miyakojima MG-20, is not present in L. burttii. In addition L. burttii has a higher level of DNA polymorphism compared to Gifu and MG-20 enabling design of codominant markers such as SSR, CAPS and dCAPS. Using an F2 population from a cross between Gifu and L. burttii, codominant makers that co-segregated at the translocation site could be expanded. In order to normalize the genetic background, L. burttii was inbred for nine generations and the germplasm L. burttii B-303-S9 was established. 相似文献
74.
E. M. J. Salentijn N. N. Sandal W. Lange Th. S. M. De Bock F. A. Krens K. A. Marcker W. J. Stiekema 《Molecular & general genetics : MGG》1992,235(2-3):432-440
Summary In cultivated beet no useful level of resistance of the beet cyst nematode (BCN) Heterodera schachtii Schm. has been found, unlike the situation in wild species of the section Procumbentes. Stable introgression of resistance genes from the wild species into Beta vulgaris has not been achieved, but resistant monosomic additions (2n =18 + 1), diploids of B. vulgaris with an extra alien chromosome carrying the resistance locus, have been obtained. Here we describe a new series of resistant monosomic fragment addition material of B. patellaris chromosome 1 (pat-1). We further describe the cloning of a single-copy DNA marker that specifically hybridizes with a monosomic addition fragment of approximately 8 Mb (AN5-90) carrying the BCN resistance locus. This marker and another fragment-specific, single-copy DNA marker probably flank the BCN locus on the addition fragment present in the AN5-203 material, which is approximately 19 Mb in size. Furthermore, several specific repetitive DNA markers have been isolated, one of which hybridizes to AN5-90 and also to DNA from a smaller DNA segment of Beta procumbens, present in line B883, carrying a BCN resistance locus introgressed into the B. vulgaris genome. This suggests that the specific repetitive marker is closely linked to the BCN locus. 相似文献
75.
Massimo Sandal Francesco Valle Isabella Tessari Stefano Mammi Elisabetta Bergantino Francesco Musiani Marco Brucale Luigi Bubacco Bruno Samorì 《PLoS biology》2008,6(1)
Human α-Synuclein (αSyn) is a natively unfolded protein whose aggregation into amyloid fibrils is involved in the pathology of Parkinson disease. A full comprehension of the structure and dynamics of early intermediates leading to the aggregated states is an unsolved problem of essential importance to researchers attempting to decipher the molecular mechanisms of αSyn aggregation and formation of fibrils. Traditional bulk techniques used so far to solve this problem point to a direct correlation between αSyn''s unique conformational properties and its propensity to aggregate, but these techniques can only provide ensemble-averaged information for monomers and oligomers alike. They therefore cannot characterize the full complexity of the conformational equilibria that trigger the aggregation process. We applied atomic force microscopy–based single-molecule mechanical unfolding methodology to study the conformational equilibrium of human wild-type and mutant αSyn. The conformational heterogeneity of monomeric αSyn was characterized at the single-molecule level. Three main classes of conformations, including disordered and “β-like” structures, were directly observed and quantified without any interference from oligomeric soluble forms. The relative abundance of the “β-like” structures significantly increased in different conditions promoting the aggregation of αSyn: the presence of Cu2+, the pathogenic A30P mutation, and high ionic strength. This methodology can explore the full conformational space of a protein at the single-molecule level, detecting even poorly populated conformers and measuring their distribution in a variety of biologically important conditions. To the best of our knowledge, we present for the first time evidence of a conformational equilibrium that controls the population of a specific class of monomeric αSyn conformers, positively correlated with conditions known to promote the formation of aggregates. A new tool is thus made available to test directly the influence of mutations and pharmacological strategies on the conformational equilibrium of monomeric αSyn. 相似文献
76.
An efficient liquid culture system for tea shoot proliferation 总被引:3,自引:0,他引:3
Sandal Indra Bhattacharya Amita Singh Ahuja Paramvir 《Plant Cell, Tissue and Organ Culture》2001,65(1):75-80
The efficiency of thidiazuron in promoting tea shoot proliferation in liquid medium was evaluated. As compared to 6-benzyl
adenine which induced hyperhydricity in the proliferated shoots in liquid medium, a progressive increase in the multiplication
rate together with healthy shoot growth was achieved when thidiazuron (2.5 to 5.0 μM) was used instead of 6-benzyl adenine.
Of the different liquid volumes compared in 250 ml Erlenmyer flasks, 20 ml was the most effective. While an increase in the
multiplication rate coupled with normal but healthy shoots was observed under static and agitated conditions at this volume
of liquid medium, hyperhydricity was induced in 50 ml liquid medium. Therefore, 20 ml static liquid medium with subculture
periods at an interval six to eight weeks seems to be a cost and labour effective process as compared to the existing protocols
involving solid media with subculture periods at 4 weeks interval.
This revised version was published online in June 2006 with corrections to the Cover Date. 相似文献
77.
The formation of the [NiFe] metallocenter of Escherichia coli hydrogenase 3 requires the participation of proteins encoded by the hydrogenase pleiotropy operon hypABCDEF. The insertion of Ni(II) into the precursor enzyme follows the incorporation of the iron center and is the function of HypA, a Zn(II)-binding protein, and HypB, a GTPase. The Ni(II) donor and the mechanism of transfer of Ni(II) into the hydrogenase precursor protein are not known. In this study, we demonstrate that HypB is a nickel-binding protein capable of binding 1 equiv of Ni(II) with a K(d) in the sub-picomolar range. In addition, HypB has a weaker metal-binding site that is not specific for Ni(II) over Zn(II). Examination of the isolated C-terminal GTPase domain revealed that the high-affinity metal binding capability was severely abrogated but the low-affinity site was intact. By mutating conserved cysteine and histidine residues in E. coli HypB, we have localized the high-affinity Ni(II)-binding site to an N-terminal CXXCGC motif and the low-affinity metal-binding site to the GTPase domain. A model for the function of HypB during the Ni(II) loading of hydrogenase is proposed. 相似文献
78.
J Ferreira S Mendes M Dall'agnol N Sandal S Sato A Pedrosa-Harand 《Cytogenetic and genome research》2012,137(1):42-49
A comparative cytogenetic map was built for Lotusuliginosus (2n = 12), expanding previous analyses that revealed intra- and interspecific chromosomal rearrangements in the model legume L. japonicus, L. filicaulis, and L. burttii. This species is positioned in a sister clade of the previously-mapped species and is proposed as one of the progenitors of L. corniculatus, the main forage crop of the genus. The cytogenetic map allowed the location of 12 genomic regions to be compared between these species. A high macrosynteny was revealed, but it was interrupted by a translocation involving chromosomes 3 and 5, a new rearrangement for the genus. Also, a transposition on chromosome 2 was found in L. japonicus 'Miyakojima'. Furthermore, changes in the number, size, and position of rDNA sites were observed, as well as an intraspecific size heteromorphism of the 5S rDNA site on L. uliginosus chromosome 6. The karyotype differences observed are proportional to the phylogenetic distance among these species. 相似文献
79.
ÜLKÜ NIHAN TAVŞANOĞLU AYŞE IDIL ÇAKIROĞLU ŞEYDA ERDOĞAN MARIANA MEERHOFF ERIK JEPPESEN MERYEM BEKLIOGLU 《Freshwater Biology》2012,57(4):795-802
1. Different behavioural responses of planktonic animals to their main predators, fish, have been reported from shallow lakes. In north temperate lakes, large‐bodied zooplankton may seek refuge from predation among macrophytes, whereas in subtropical lakes, avoidance of macrophytes has been observed. The prevalent behaviour probably depends on the characteristics of the fish community, which in Mediterranean lakes is typically dispersed in both the open water zone and in the littoral, as in temperate lakes, and is dominated by small size classes, as in subtropical lakes. 2. We performed ‘habitat choice’ experiments to test the response of Daphnia magna to predation cues at both the horizontal and vertical level by mimicking a ‘shallow littoral’ zone with plants and a ‘deeper pelagic’ zone with sediments. 3. Initial separate response experiments showed that natural plants, artificial plants and predation cues all repelled D. magna in the absence of other stimuli, while sediments alone did not trigger any significant response by D. magna. 4. The habitat choice experiments showed that, in the presence of predation cues and absence of plants, Daphnia moved towards areas with sediment. In the presence of both plants and sediments, Daphnia moved away from the plants towards the sediments under both shallow and deep water treatment conditions. 5. Based on these results, we suggest that Daphnia in Mediterranean shallow lakes avoid submerged macrophytes and instead prefer to hide near the sediment when exposed to predation risk, as also observed in subtropical shallow lakes. This pattern is not likely to change with water level alterations, a common feature of lakes in the region, even if the effectiveness of the refuge may be reduced. 相似文献
80.
Jakob Fredslund Lene H Madsen Birgit K Hougaard Anna Marie Nielsen David Bertioli Niels Sandal Jens Stougaard Leif Schauser 《BMC genomics》2006,7(1):1-10