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1.
The promotion of anthocyanin synthesis in red-cabbage seedlings by 5 min exposure to R light is inhibited by subsequent application of CaCl2. The stimulation of dark synthesis of anthocyanin by n-PrOH and by kinetin is also reduced by Ca2+ and by cholesterol, both of which are well known to stabilize cell membranes. By contrast, EDTA, which chelates Ca2+, promotes dark synthesis of anthocyanin. Assay of native Ca2+ extractable from seedlings immersed in EDTA demonstrates that R light exposure promotes a highly significant increase in extractable Ca2+. It is suggested that the molecular configuration of the phytochrome molecule affects the ability of a membrane to bind Ca2+ and that this in turn affects the permeability to substrates which are required for anthocyanin biosynthesis. 相似文献
2.
Patrone Vania Al-Surrayai Tahani Romaniello Francesco Fontana Alessandra Milani Giovanni Sagheddu Valeria Puglisi Edoardo Callegari Maria Luisa Al-Mansour Hamad Kishk Mohamed Waheed Morelli Lorenzo 《Probiotics and antimicrobial proteins》2021,13(3):809-823
Probiotics and Antimicrobial Proteins - Probiotics represent a possible strategy for controlling intestinal infections in livestock. Members of the Weissella genus are increasingly being studied... 相似文献
3.
Kinetin stimulates the synthesis of anthocyanin in dark-grown seedlings of red-cabbage. When applied for only 15 min its effect resembles that of 5 min R light and can be nullified by a subsequent exposure to 5 min FR. However, kinetin fails to stimulate PAL activity in the dark-grown seedlings. It is suggested that the effect of kinetin, like that of R light, may be to increase membrane permeability, allowing a pool of endogenous substrate to reach the site of anthocyanin biosynthesis. 相似文献
4.
Jameel M. Al-Khayri Feng H. Huang Teddy E. Morelock Tahani A. Busharar 《In vitro cellular & developmental biology. Plant》1992,28(2):64-66
Summary A system for the regeneration of spinach (Spinacia oleracea L.) from mature dry seed explants has been established. The response of two commercial spinach cultivars, ‘Grandstand’ and
‘Baker’, was examined. Callus proliferation was most prominent on MS medium supplemented with 9.3 μM of 6-furfurylaminopurine (kinetin) and 3.39 μM 2,4-dichlorophenoxyacetic acid (2,4-D). Adventitious shoot formation was observed within 8 wk after callus was transferred
onto regeneration medium. Shoot regeneration was best from callus induced on 9.3 μM kinetin and 4.56 μM 2,4-D. The regeneration medium contained 9.3 μM kinetin, 0.045 μM 2,4-D, and 2.89 μM gibberellic acid (GA3). Shoots were rooted on hormone-free medium, and plants grown in a greenhouse showed normal phenotype. This system is beneficial
in rapid propagation of spinach plants, particularly when only a limited number of seeds are available. 相似文献
5.
Possible protective mechanisms exerted by metformin or metformin and vitamin E in isoproterenol‐induced cardiac injury 下载免费PDF全文
6.
This article reports on a qualitative investigation of 15 young Muslim-American women living in New York City, after 9/11 and in the midst of the Patriot Act. Participants completed surveys about identity, discrimination, and coping; drew “identity maps” to represent their multiple identities and alliances; and participated in focus groups on several college campuses in the New York metropolitan area. Focus groups were conducted to investigate collectively their sense of hyphenated identities, their experiences of surveillance and their responses to scrutiny in families, communities, on the streets and in the political public sphere. Implications for the theoretical and empirical study of immigrant youth “under siege” are developed, with a particular focus on the burdens and responsibilities embodied by daughters of the second generation of Muslim-Americans. 相似文献
7.
How do species barriers decay? Concordance and local introgression in mosaic hybrid zones of mussels
Alexis Simon Christelle Fraïsse Tahani El Ayari Cathy Liautard‐Haag Petr Strelkov John J. Welch Nicolas Bierne 《Journal of evolutionary biology》2021,34(1):208-223
The Mytilus complex of marine mussel species forms a mosaic of hybrid zones, found across temperate regions of the globe. This allows us to study ‘replicated’ instances of secondary contact between closely related species. Previous work on this complex has shown that local introgression is both widespread and highly heterogeneous, and has identified SNPs that are outliers of differentiation between lineages. Here, we developed an ancestry‐informative panel of such SNPs. We then compared their frequencies in newly sampled populations, including samples from within the hybrid zones, and parental populations at different distances from the contact. Results show that close to the hybrid zones, some outlier loci are near to fixation for the heterospecific allele, suggesting enhanced local introgression, or the local sweep of a shared ancestral allele. Conversely, genomic cline analyses, treating local parental populations as the reference, reveal a globally high concordance among loci, albeit with a few signals of asymmetric introgression. Enhanced local introgression at specific loci is consistent with the early transfer of adaptive variants after contact, possibly including asymmetric bi‐stable variants (Dobzhansky‐Muller incompatibilities), or haplotypes loaded with fewer deleterious mutations. Having escaped one barrier, however, these variants can be trapped or delayed at the next barrier, confining the introgression locally. These results shed light on the decay of species barriers during phases of contact. 相似文献
8.
Wafa Bouzid Jan Štefka Lilia Bahri-Sfar Peter Beerli Géraldine Loot Sovan Lek Noura Haddaoui Václav Hypša Tomáš Scholz Tahani Dkhil-Abbes Rafik Meddour Oum Kalthoum Ben Hassine 《Biological invasions》2013,15(9):1907-1923
Introduced species have the potential to outperform natives via the introduction of new parasites to which the native ecosystem is vulnerable. Cryptic diversity within an invasive species can obscure invasion patterns and confound proper management measures. The aim of this study is to use coalescent theory based methodology to trace recent routes of invasion in populations of Ligula intestinalis, a globally distributed fish parasite possessing both native and recently introduced populations in North Africa. Molecular analyses of mitochondrial DNA discerned a pronounced genetic divergence between introduced and native populations. Distribution of mitochondrial haplotypes demonstrated common origin of European populations with North African parasites sampled from introduced fish species in Tunisia. To test the suggested pathway of introduction, microsatellite data were examined in a model-based coalescent analysis using the software MIGRATE, where Europe to Tunisia direction of migration was favoured over alternative hypotheses of gene flow. Specificity of Tunisian populations to different host species was assessed in an epidemiologic survey confirming prevailing host-based division between introduced and native parasites in North Africa. This approach combining advanced analysis of molecular markers with host-specificity data allows revealing the evolution of host-parasite interactions following biological invasion and provides basis for devising future management measurements. 相似文献
9.
A. Mesut Erzurumluoglu Muslim M. Alsaadi Santiago Rodriguez Tahani S. Alotaibi Philip A. I. Guthrie Sian Lewis Aasiya Ginwalla Tom R. Gaunt Khalid K. Alharbi Fahad M. Alsaif Basma M. Alsaadi Ian N. M. Day 《PloS one》2015,10(3)
Papillon-Lefevre syndrome (PLS) is an autosomal recessive disorder characterised by severe early onset periodontitis and palmoplantar hyperkeratosis. A previously reported missense mutation in the CTSC gene (NM_001814.4:c.899G>A:p.(G300D)) was identified in a homozygous state in two siblings diagnosed with PLS in a consanguineous family of Arabic ancestry. The variant was initially identified in a heterozygous state in a PLS unaffected sibling whose whole exome had been sequenced as part of a previous Primary ciliary dyskinesia study. Using this information, a proxy molecular diagnosis was made on the PLS affected siblings after consent was given to study this second disorder found to be segregating within the family. The prevalence of the mutation was then assayed in the local population using a representative sample of 256 unrelated individuals. The variant was absent in all subjects indicating that the variant is rare in Saudi Arabia. This family study illustrates how whole-exome sequencing can generate findings and inferences beyond its primary goal. 相似文献
10.
Florentine Riquet Cathy Liautard‐Haag Lucy Woodall Carmen Bouza Patrick Louisy Bojan Hamer Francisco Otero‐Ferrer Philippe Aublanc Vickie Bduneau Olivier Briard Tahani El Ayari Sandra Hochscheid Khalid Belkhir Sophie Arnaud‐Haond Pierre‐Alexandre Gagnaire Nicolas Bierne 《Evolution; international journal of organic evolution》2019,73(4):817-835
Diverging semi‐isolated lineages either meet in narrow clinal hybrid zones, or have a mosaic distribution associated with environmental variation. Intrinsic reproductive isolation is often emphasized in the former and local adaptation in the latter, although both reduce gene flow between groups. Rarely are these two patterns of spatial distribution reported in the same study system. Here, we report that the long‐snouted seahorse Hippocampus guttulatus is subdivided into discrete panmictic entities by both types of hybrid zones. Along the European Atlantic coasts, a northern and a southern lineage meet in the southwest of France where they coexist in sympatry—i.e., in the same geographical zone—with little hybridization. In the Mediterranean Sea, two lineages have a mosaic distribution, associated with lagoon‐like and marine habitats. A fifth lineage was identified in the Black Sea. Genetic homogeneity over large spatial scales contrasts with isolation maintained in sympatry or close parapatry at a fine scale. A high variation in locus‐specific introgression rates provides additional evidence that partial reproductive isolation must be maintaining the divergence. We find that fixed differences between lagoon and marine populations in the Mediterranean Sea belong to the most differentiated SNPs between the two Atlantic lineages, against the genome‐wide pattern of structure that mostly follow geography. These parallel outlier SNPs cluster on a single chromosome‐wide island of differentiation. Since Atlantic lineages do not map to lagoon‐sea habitat variation, genetic parallelism at the genomic island suggests a shared genetic barrier contributes to reproductive isolation in contrasting contexts–i.e., spatial versus ecological. We discuss how a genomic hotspot of parallel differentiation could have evolved and become associated both with space and with a patchy environment in a single study system. 相似文献