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151.
Background
Retrotransposons are heterogeneous sequences, widespread in eukaryotic genomes, which refer to the so-called mobile DNA. They resemble retroviruses, both in their structure and for their ability to transpose within the host genome, of which they make up a considerable portion. Copia- and Gypsy-like retrotransposons are the two main classes of retroelements shown to be ubiquitous in plant genomes. Ideally, the retrotransposons life cycle results in the synthesis of a messenger RNA and then self-encoded proteins to process retrotransposon mRNA in double stranded extra-chromosomal cDNA copies which may integrate in new chromosomal locations. 相似文献152.
Cuzzoni Elena; Giordani Chiara; Stampacchia Otello; Bolchi Angelo; Malcevschi Aliosha; Ottonello Simone; Ferretti Luca; Sala Francesco 《Plant & cell physiology》1995,36(4):717-725
Sequence analysis of twelve DNA fragments, which had previouslybeen found to be extensively amplified in suspension-culturedrice cells, revealed that two of them, isolated on plasmidsdesignated pE10 and pE11, have sequences identical to distinctregions of chloroplast DNA (ct-DNA). Both sequences are partof an extrachromosomal circular DNA molecule (ECD). The molecularstructure of the ECD was investigated by a combination of restrictionanalysis, standard and pulsed-field gel electrophoresis, hybridizationwith ct-DNA probes and amplification by the polymerase chainreaction in the presence of oligonucleotide primers homologousto selected regions of rice ct-DNA. The results showed thata continuous and unrearranged stretch of ct-DNA from the longsingle-copy region, of at least 28 kbp in length, is presentin the ECD. It was estimated that the number of copies of theECD in cultured cells was almost equivalent to that of ct-DNAmolecules in rice leaves, while the ratio of ECD to ct-DNA moleculesin the cultured cells was approximately 200: 1. (Received December 12, 1994; Accepted April 4, 1995) 相似文献
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154.
A beta-fucosidase located in the latex serum of Lactuca sativa has been isolated and purified to homogeneity. This enzyme greatly differs from the other fucosidases already known in that it is strictly specific for the fucosyl residue and for the anomeric beta carbon. It is the first time that such an enzyme is shown to exist. The enzyme is a monomer and its molecular mass is close to 37 kDa. Its sedimentation constant is equal to 2.8 S. It is very stable at pH 5.5 in citrate/phosphate buffer but extensive denaturation occurs up to pH 7.5. Kinetic studies have shown that two ionization steps probably control the rate of the enzymatic hydrolysis. No precise information could be obtained about the possible in vivo role of this beta-fucosidase. However, the pure enzyme can release fucose from the cell walls obtained from hypocotyls of L. sativa. This result may be taken as evidence for the presence of beta-fucosidic links in these walls so that the enzyme could be involved in the differentiation of articulated laticifers. 相似文献
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156.
G. Astuti S. Brullo G. Domina R. El Mokni T. Giordani L. Peruzzi 《Plant biosystems》2017,151(6):1120-1128
In the south-central Mediterranean four tetraploid species of Bellevalia occur: B. dolichophylla, B. galitensis, B. mauritanica, and B. pelagica. Another group of plants, morphologically similar to B. dolichophylla, has been recently recovered in Zembra Island (Tunisia). A phylogenetic reconstruction involving all these tetraploid taxa was performed using both plastidial and nuclear markers (trnL-trnF and ITS, respectively). For all these taxa, an allopolyploid origin involving B. romana and B. dubia is supported. Regarding plants from Zembra, they may fall within the variability of B. dolichophylla. 相似文献
157.
Piyali Sabui Sadhucharan Mallick Kshitij RB Singh Arunadevi Natarajan Ranjana Verma Jay Singh Ravindra Pratap Singh 《Luminescence》2023,38(7):1047-1063
Food safety and quality are among the most significant and prevalent research areas worldwide. The fabrication of appropriate technical procedures or devices for the recognition of hazardous features in foods is essential to safeguard food materials. In the recent era, developing high-performance sensors based on carbon nanomaterial for food safety investigation has made noteworthy progress. Hence this review briefly highlights the different detection approaches (colorimetric sensor, fluorescence sensor, surface-enhanced Raman scattering, surface plasmon resonance, chemiluminescence, and electroluminescence), functional carbon nanomaterials with various dimensions (quantum dots, graphene quantum dots) and detection mechanisms. Further, this review emphasizes the assimilation of carbon nanomaterials with optical sensors to identify multiple contaminants in food products. The insights of carbon-based nanomaterials optical sensors for pesticides and insecticides, toxic metals, antibiotics, microorganisms, and mycotoxins detection are described in detail. Finally, the opportunities and future perspectives of nanomaterials-based optical analytical approaches for detecting various food contaminants are discussed. 相似文献
158.
L. Natali T. Giordani E. Polizzi C. Pugliesi M. Fambrini A. Cavallini 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》1998,97(8):1240-1247
The genome of a Helianthus annuus (2n=34) ×Helianthus tuberosus (2n=102) hybrid was studied at cytological, biochemical and molecular levels and compared to those of the parental species.
Cytophotometric analyses showed that the hybrid has a 4C DNA content higher than expected and with a larger variability than
in the parents. This high variability is probably not related to chromosome-number variations since the hybrid always had
2n=68 chromosomes. Moreover, hybrid interphase nuclei showed lower heterochromatin condensation than the parental ones. Thermal
denaturation of genomic DNAs indicated that quantitative variation of some DNA families occurred in the hybrids compared to
parents. Finally, molecular analyses of DNAs restricted with different enzymes, after Southern blotting and hybridization
with HR probes, showed restriction patterns in the hybrid different from those observed in parents. These results indicate
that interspecific hybridization between H. annuus and H. tuberosus may determine quantitative variation of some DNA families and differential DNA methylations that probably modify the nuclear
structure. These phenomena are probable responses to a “genomic shock” following the interspecific cross.
Received: 22 May 1998 / Accepted: 4 June 1998 相似文献
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