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1.
Hardies SC; Martin SL; Voliva CF; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1986,3(2):109-125
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G. M. Fahmy 《Biologia Plantarum》1993,35(4):603-608
The angiosperm root parasiteCynomorium coccineum and the halophytic hostsLimonium delicatulum andArthrocnemum glaucum were invesrigated under natural conditions in a Mediterranean salt marsh in March 1992. The diurnal transpiration rate of the parasite was low and parallel to the climatic factors. The non-infected plants showed higher transpiration rates than the parasite and its hosts. Compared to the non-infected plants, it is apparent that the perennial herbL. delicatulum is more sensitive to infection since its reduction in the fresh and dry mass was higher than that found inA. glaucum. 相似文献
4.
A major difference between the divergence patterns within the lines-1 families in mice and voles 总被引:3,自引:0,他引:3
Vanlerberghe F; Bonhomme F; Hutchison CA d; Edgell MH 《Molecular biology and evolution》1993,10(4):719-731
L1 retroposons are represented in mice by subfamilies of interspersed
sequences of varied abundance. Previous analyses have indicated that
subfamilies are generated by duplicative transposition of a small number of
members of the L1 family, the progeny of which then become a major
component of the murine L1 population, and are not due to any active
processes generating homology within preexisting groups of elements in a
particular species. In mice, more than a third of the L1 elements belong to
a clade that became active approximately 5 Mya and whose elements are >
or = 95% identical. We have collected sequence information from 13 L1
elements isolated from two species of voles (Rodentia: Microtinae: Microtus
and Arvicola) and have found that divergence within the vole L1 population
is quite different from that in mice, in that there is no abundant
subfamily of homologous elements. Individual L1 elements from voles are
very divergent from one another and belong to a clade that began a period
of elevated duplicative transposition approximately 13 Mya. Sequence
analyses of portions of these divergent L1 elements (approximately 250 bp
each) gave no evidence for concerted evolution having acted on the vole L1
elements since the split of the two vole lineages approximately 3.5 Mya;
that is, the observed interspecific divergence (6.7%-24.7%) is not larger
than the intraspecific divergence (7.9%-27.2%), and phylogenetic analyses
showed no clustering into Arvicola and Microtus clades.
相似文献
5.
Ahmed Gamal El-Din Fahmy 《Vegetation History and Archaeobotany》1997,6(4):241-247
Macrofossils of weeds retrieved from archaeological sediments in Egypt are discussed in terms of their presence, preservation and representation significance. The study reveals 112 field weeds from 61 archaeological sites dating from Predynastic times (4500 B.C.) up to the Graeco-Roman period (A.D. 395). Most of the remains were preserved by desiccation. The 112 listed species include 24 taxa from Predynastic Hierakonpolis (3800–3500 B.C.) identified for the first time. This study is based on a selection of 97 species from the entire list. Interpretation of field weed finds from the archaeological contexts is discussed. The highest number of species, 63, is recorded from the Pharaonic period. The Predynastic era is represented by 46 species and the Graeco-Roman period by 34. The intensive archaeological excavation of Pharaonic settlements may explain the rich flora of that period compared with the two others. Floristic analysis shows that 57 species were introduced in association with crops from the Middle East and 40 may belong to the native vegetation of the Nile valley. 相似文献
6.
Structural investigation of bacteriorhodopsin and some of its photoproducts by polarized Fourier transform infrared spectroscopic methods-difference spectroscopy and photoselection 总被引:1,自引:1,他引:0
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The direction of selected IR-transition moments of the retinal chromophore of bacteriorhodopsin (BR) and functional active amino acid residues are determined for light- and dark-adapted BR and for the intermediates K and L of the photocycle. Torsions around single bonds of the chromophore are found to be present in all the investigated BR states. The number of twisted single bonds and the magnitude of these torsions decreases in the order K, L, light-adapted BR, dark-adapted BR. In the last, only the C14—C15 single bond is twisted. The orientation of molecular planes and chemical bonds of such protein side chains, which are perturbed during the transition of light-adapted BR to the respective intermediates, are deduced and the results compared with the current three dimensional model of BR. Trp 86 and Trp 185 are found to form a rigid part of the protein, whereas Asp 96 and Asp 115 perform molecular rearrangements upon formation of the L-intermediate. 相似文献
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The genetic properties of the hepatocarcinogen N,N-dimethylnitrosamine (DMN) were examined in Drosophila for the assessment of the role of dose, cellular metabolism and genic target in its mutagenicity. Genetic activity was assayed with respect to the induction of the non-specific X-chromosome recessives (lethals and visibles) relative to the effects on specific genic sites, especially rDNA, which yields bobbed (bb) mutations.Dose dependence followed a quadratic course for all mutational classes and germ cell types, which indicated that DMN induced at least some multiple-hit mutagenic events. The genetic activity of DMN was favoured by cellular metabolism for all mutational classes, as was indicated by the progressive increase in mutation yield during spermatogenesis — from the metabolically inert mature sperm to the actively metabolizing spermatocytes and spermatogonia.The role of DNA methylation in the mutagenicity of DMN was deduced from quantitative assays of its genetic activity relative to the methylating nitrosamide — N-methyl-N-nitrosourethane (MNUr) — over the same dose range (1–10 mM) and on identical cell types and genic targets. In the metabolically inert cells (mature sperm), the two compounds were equally active with respect to the non-specific effects (X-recessives), but MNUr was considerably more effective on rDNA (bb's). Conversely, in the metabolically active cells (spermatocytes and spermatogonia), DMN exerted a much higher non-specific mutagenicity than MNUr, but the two compounds were equally effective on rDNA. These results could not be entirely interpreted by the methylation hypothesis and indicated that a DMN aldehydic metabolite, structurally analogous to MNUr, might be responsible for the induction of the rDNA mutations.The rDNA selectivity index of DMN was significantly lower than for MNUr, which paralleled their relative carcinogenic versatilities. However, DMN was comparatively more effective on the tRNA genes, a feature which might be associated with its oncogenic specificity. 相似文献
9.
Md. Ashraful Alam Milan Skalicky Muhammad Rezaul Kabir Md. Monwar Hossain Md. Abdul Hakim Md. Siddikun Nabi Mandal Rabiul Islam Md. Babul Anwar Akbar Hossain Fahmy Hassan Amaal Mohammadein Muhammad Aamir Iqbal Marian Brestic Mohammad Anwar Hossain Khalid Rehman Hakeem Ayman EL Sabagh 《Phyton》2021,90(4):1301-1320
Globally among biotic stresses, diseases like blight, rust and blast constitute prime constraints for reducing wheat
productivity especially in Bangladesh. For sustainable productivity, the development of disease-resistant lines and
high yielding varieties is vital and necessary. This study was conducted using 122 advanced breeding lines of
wheat including 21 varieties developed by Bangladesh Wheat and Maize Research Institute (BAMRI) with aims
to identify genotypes having high yield potential and resistance to leaf blight, leaf rust and blast diseases. These
genotypes were evaluated for resistance against leaf blight and leaf rust at Dinajpur and wheat blast at Jashore
under field condition. Out of 122 genotypes tested, 20 lines were selected as resistant to leaf blight based on
the area under the diseases progress curve (AUDPC) under both irrigated timely sown (ITS) and irrigated late
sown (ILS) conditions. Forty-two genotypes were found completely free from leaf rust infection, 59 genotypes
were identified as resistant, and 13 genotypes were identified as moderately resistant to leaf rust. Eighteen genotypes were immune against wheat blast, 42 genotypes were categorized as resistant, and 26 genotypes were identified as moderately resistant to wheat blast. Molecular data revealed that the 16 genotypes showed a positive 2NS
segment among the 18 immune genotypes selected against wheat blast under field conditions. The genotypes
BAW 1322, BAW 1295, and BAW 1203 can be used as earlier maturing genotypes and the genotypes BAW
1372, BAW 1373, BAW 1297 and BAW 1364 can be used for lodging tolerant due to short plant height. The genotypes WMRI Gom 1, BAW 1349 and BAW 1350 can be selected for bold grain and the genotypes WMRI Gom 1,
BAW 1297, BAW 1377 can be used as high yielder for optimum seeding condition but genotypes BAW 1377
and BAW 1366 can be used for late sown condition. The selected resistant genotypes against specific diseases can be used in the further breeding program to develop wheat varieties having higher disease resistance and
yield potential. 相似文献
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