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1.
Reactions of the trichloromethylperoxy free radical (Cl3COO) with tryptophan, tryptophanyl-tyrosine and lysozyme 总被引:1,自引:0,他引:1
J E Packer J S Mahood R L Willson B S Wolfenden 《International journal of radiation biology and related studies in physics, chemistry, and medicine》1981,39(2):135-141
The trichloromethyl peroxy radical Cl3COO reacts with tryptophan, tryptophanyl-tyrosine and with lysozyme to form products whose overall absorption spectrum is different from those observed following the reaction of hydroxyl, bromide, thiocyanate or azide radicals. Two spectral components have been identified: a minor component attributed to the neutral tryptophanyl radical which can react with ascorbate and intramolecularly with tyrosine residues and a major component which does not undergo either of these reactions and is probably a radical adduct. 相似文献
2.
Balancing ever-increasing agricultural and biofuel needs with biodiversity conservation is one of the greatest challenges
facing conservation biologists in the 21st century. The conversion of >75 million hectares of forests in Brazilian Amazonia
over four decades for agropastoral uses has resulted in the ‘creation’ of a similar-sized amount of non-forest ‘agricultural
matrix’ habitats. Despite extensive research on the effects of forest loss and fragmentation on the Amazonian biota, the value
of increasingly larger areas of non-forest habitat for forest wildlife remains poorly understood. We conducted 325 fixed-radius
point counts of the avifaunal assemblage of non-forest vegetation within a 1200-km2 region along the Amazonian ‘Arc of Deforestation’ in Northern Mato Grosso, Brazil. Our sampling included 2,814 records of
164 species, 15 and 54% of which were recorded in more than 10% and fewer than 2% of all sampling sites, respectively. In
particular, nearly 70% of the regional scale avifauna of 560 species failed to use the agricultural matrix, regardless of
the persistence of ameliorating structural features, such as isolated trees. At the local scale, higher species richness in
the agricultural matrix was best predicted by the presence of relictual trees, and to a lesser extent by standing water and
scrubby habitats. The presence of relictual trees, rather than scrub, predicted the occurrence of those forest-dependent species
that did use the agricultural matrix. Our results indicate that intensive agricultural production coupled with land sparing
would better suit conservation of vulnerable forest species than more extensive ‘wildlife friendly’ agricultural practices
that require more land under production to produce the same yield. 相似文献
3.
MARIÁN PERNÝ VLADISLAV KOLARIK L'UBO MAJESKÝ PAVOL MÁRTONFI 《Botanical journal of the Linnean Society. Linnean Society of London》2008,157(3):475-485
Cytogeographical variability within the Phleum pratense group in the Carpathians and adjacent part of Pannonian lowland, based on 132 populations analysed by flow cytometry, is described. Only diploid and hexaploid plants were detected among 635 samples from the studied area. Diploids were found to be less frequent (127 plants, 20%) than hexaploids (508, 80%). With the exception of the single pure diploid population, diploids always co-occured with hexaploids (30 localities, 22.7%). The majority of populations (101, 76.5%) consisted of hexaploid plants. Most mixed populations occur in the Western Carpathians (26). In the Eastern Carpathians, mixed populations are much rarer, with three populations in Ukraine and one in Romania. In the Southern Carpathians, only hexaploids occur. The conventional taxonomic concept of the two species, diploid P. bertolonii and hexaploid P. pratense , was followed in spite of their sympatric occurence. Distribution maps based on chromosome number data from previous studies and on ploidy level estimates are given for both species in the studied area. The pattern of different distribution of the two taxa within the Carpathians is discussed. © 2008 The Linnean Society of London, Botanical Journal of the Linnean Society , 2008, 157 , 475–485. 相似文献
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Dale?G.?MiquelleEmail author Colin?M.?Poole Simon?P.?Mahood Henry?Travers Matt?Linkie J.?Goodrich Joe?Walston Kenserey?Rotha Alan?Rabinowtiz 《Biodiversity and Conservation》2018,27(12):3287-3293
We comment on five aspects of Gray et al.’s (Biodivers Conserv, https://doi.org/10.1007/s10531-017-1365-1, 2017a) framework for assessing the readiness of sites for tiger reintroductions. Clarifications in numbers of tigers, available habitat and prey requirements indicate that more land and additional recovery of preferred prey species will be critical for a successful reintroduction. A focus on threat assessments and mitigations will be more important than a focus on site management tools. Local attitudes and levels of poaching require more attention than in the current assessment, as they are likely to be major obstacles to successful large carnivore reintroductions in Asia. Given the limited resources for rangewide tiger conservation, the value of such long-term initiatives must be weighed relative to the urgent need to recover and secure existing tiger populations before they also become extinct. 相似文献
6.
328 X-linked recessive lethal mutations induced in late spermatids by hycanthone methanesulfonate were tested for coverage by duplications that comprised, in total, about 24% of the euchromatic X chromosome; 78 lethals appeared to be covered. Crossover localization tests of a random sample of 38 non-covered lethals revealed 4 chromosomes carrying a lethal within a duplicated segment. Lethals localized to a particular region were crossed to reference deficiencies and single-locus mutations, and inter se, to ascertain their genetic extent. The proportion of multi-locus deletions among these 78 covered and 4 non-covered lethals was 3/48, 1/10 and 13/24 for the distal, medial and proximal regions, respectively. A storage period of 9 days did not noticeably influence these proportions. In the sample of 38 non-covered lethals, and among 17 of the covered single-site lethals, 4 cases of strong crossover suppression were detected. Comparison of these results with data obtained with other mutagens suggests that induction of multi-locus deletions, and possibly of other types of chromosome rearrangement, could in part depend on other mechanisms than those acting in the formation of translocations and chromosome loss. For the purpose of mutagen testing, these findings imply that, in Drosophila, results in the regular genetic tests for chromosome breakage events do not always accurately predict the capacity of a mutagen to induce multi-locus deletions. This is of importance since transmissible multi-locus deletions have been considered a significant source of genetic damage in man. 相似文献
7.
Aylin
ZDEMR BAHADIR Bertan Koray BALCIOLU Müge SERHATLI eyma IIK Berrin ERDA 《Turkish Journal of Biology》2021,45(6):674
Gelatinases A and B, which are members of the matrix metalloproteinase (MMP) family, play essential roles in cancer development and metastasis, as they can break down basal membranes. Therefore, the determination and inhibition of gelatinases is essential for cancer treatment. Peptides that can specifically block each gelatinase may, therefore, be useful for cancer treatment. In this study, subtractive panning was carried out using a 12-mer peptide library to identify peptides that block gelatinase A activity (MMP-2), which is a key pharmacological target. Using this method, 17 unique peptide sequences were determined. MMP-2 inhibition by these peptides was evaluated through zymogram analyses, which revealed that four peptides inhibited MMP-2 activity by at least 65%. These four peptides were synthesized and used for in vitro wound healing using human umbilical vein endothelial cells, and two peptides, AOMP12 and AOMP29, were found to inhibit wound healing by 40%. These peptides are, thus, potential candidates for MMP-2 inhibition for cancer treatment. Furthermore, our findings suggest that our substractive biopanning screening method is a suitable strategy for identifying peptides that selectively inhibit MMP-2. 相似文献
8.
Sinem DEMRBA-SARIKAYA Hatice AKIR Devrim G
ZÜAIK Yunus AKKO 《Turkish Journal of Biology》2021,45(3):235
Autophagy and DNA repair are two essential biological mechanisms that maintain cellular homeostasis. Impairment of these mechanisms was associated with several pathologies such as premature aging, neurodegenerative diseases, and cancer. Intrinsic or extrinsic stress stimuli (e.g., reactive oxygen species or ionizing radiation) cause DNA damage. As a biological stress response, autophagy is activated following insults that threaten DNA integrity. Hence, in collaboration with DNA damage repair and response mechanisms, autophagy contributes to the maintenance of genomic stability and integrity. Yet, connections and interactions between these two systems are not fully understood. In this review article, current status of the associations and crosstalk between autophagy and DNA repair systems is documented and discussed. 相似文献
9.
J.E. Packer J.S. Mahood V.O. Mora-Arellano T.F. Slater R.L. Willson B.S. Wolfenden 《Biochemical and biophysical research communications》1981,98(4):901-906
The ‘singlet oxygen scavengers’. 1,4-diazobicyclo(2,2,2)-octane (DABCO), diphenyl furan and β-carotene react rapidly with the organic peroxyradical CCl3O2?. The absolute reaction rate constants k = 1.2 ± 0.2 × 107, 6 ± 2 × 107 at 1.5 ± 0.2 × 109 M?1s?1 respectively have been determined by pulse radiolysis. Comparison with other data suggest that other free radicals are also likely to react with these compounds; in the case of the hydroxyl radical and DABCO k = 1.25 × 109 M?1s?1 has been determined. 相似文献
10.
Genya Mitani Masato Sato Jeong IK Lee Nagatoshi Kaneshiro Miya Ishihara Naoshi Ota Mami Kokubo Hideaki Sakai Tetsutaro Kikuchi Joji Mochida 《BMC biotechnology》2009,9(1):17-11