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1.
Leaf surfaces of non-tissue-cultured, vitrified and non-vitrified plantlets of Gypsophila paniculata (Babies Breath) were examined using an environmental scanning electron microscope. Non-tissue-cultured plants had a complete epidermal surface, recessed stomata and wax present on the leaf surface. The surface of tissue-cultured plantlets appeared similar to non-tissue-cultured plants excepting stomata were slightly protruding and less wax appeared to be present. In both non-tissue-cultured and tissue-cultured plants stomata were found both opened and closed and were observed closing. In contrast vitrified plantlets had abnormal, malformed stomata which appeared non-functional. The ventral surfaces of leaves seemed more normal than the dorsal, this may be due to the former receiving more light. Additionally, discontinuities were found in the epidermis. Often epidermal holes were found in association with stomatal apertures. It is suggested that the main cause of desiccation of vitrified G. paniculata plantlets ex vitro is due to loss of water from the discontinuity in epidermis and not because of non-functional stomata. Liquid water could be seen through the epidermal holes indicating that at least some of the extra water in vitrified plantlets is contained in the intercellular spaces.Abbreviations ESEM
Environmental scanning election microscope
- IAA
Indole acetic acid
- NTC
Non-tissue-cultured
- TC
Tissue-cultured
- V
vitrified 相似文献
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Susan M. Gribble Frances K. Wiseman Stephen Clayton Elena Prigmore Elizabeth Langley Fengtang Yang Sean Maguire Beiyuan Fu Diana Rajan Olivia Sheppard Carol Scott Heidi Hauser Philip J. Stephens Lucy A. Stebbings Bee Ling Ng Tomas Fitzgerald Michael A. Quail Ruby Banerjee Kai Rothkamm Victor L. J. Tybulewicz Elizabeth M. C. Fisher Nigel P. Carter 《PloS one》2013,8(4)
Down syndrome (DS) is caused by trisomy of chromosome 21 (Hsa21) and presents a complex phenotype that arises from abnormal dosage of genes on this chromosome. However, the individual dosage-sensitive genes underlying each phenotype remain largely unknown. To help dissect genotype – phenotype correlations in this complex syndrome, the first fully transchromosomic mouse model, the Tc1 mouse, which carries a copy of human chromosome 21 was produced in 2005. The Tc1 strain is trisomic for the majority of genes that cause phenotypes associated with DS, and this freely available mouse strain has become used widely to study DS, the effects of gene dosage abnormalities, and the effect on the basic biology of cells when a mouse carries a freely segregating human chromosome. Tc1 mice were created by a process that included irradiation microcell-mediated chromosome transfer of Hsa21 into recipient mouse embryonic stem cells. Here, the combination of next generation sequencing, array-CGH and fluorescence in situ hybridization technologies has enabled us to identify unsuspected rearrangements of Hsa21 in this mouse model; revealing one deletion, six duplications and more than 25 de novo structural rearrangements. Our study is not only essential for informing functional studies of the Tc1 mouse but also (1) presents for the first time a detailed sequence analysis of the effects of gamma radiation on an entire human chromosome, which gives some mechanistic insight into the effects of radiation damage on DNA, and (2) overcomes specific technical difficulties of assaying a human chromosome on a mouse background where highly conserved sequences may confound the analysis. Sequence data generated in this study is deposited in the ENA database, Study Accession number: ERP000439. 相似文献
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Anne M. Bronikowski Richard P. Meisel Peggy R. Biga James
R. Walters Judith E. Mank Erica Larschan Gerald S. Wilkinson Nicole Valenzuela Ashley Mae Conard Joo Pedro de Magalhes Jingyue
Duan Amy E. Elias Tony Gamble Rita
M. Graze Kristin E. Gribble Jill A. Kreiling Nicole C. Riddle 《Aging cell》2022,21(2)
Sex differences in aging occur in many animal species, and they include sex differences in lifespan, in the onset and progression of age‐associated decline, and in physiological and molecular markers of aging. Sex differences in aging vary greatly across the animal kingdom. For example, there are species with longer‐lived females, species where males live longer, and species lacking sex differences in lifespan. The underlying causes of sex differences in aging remain mostly unknown. Currently, we do not understand the molecular drivers of sex differences in aging, or whether they are related to the accepted hallmarks or pillars of aging or linked to other well‐characterized processes. In particular, understanding the role of sex‐determination mechanisms and sex differences in aging is relatively understudied. Here, we take a comparative, interdisciplinary approach to explore various hypotheses about how sex differences in aging arise. We discuss genomic, morphological, and environmental differences between the sexes and how these relate to sex differences in aging. Finally, we present some suggestions for future research in this area and provide recommendations for promising experimental designs. 相似文献
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Fenwick AE Garnier B Gribble AD Ife RJ Rawlings AD Witherington J 《Bioorganic & medicinal chemistry letters》2001,11(2):195-198
Using solid-phase synthesis, a library of novel cyclic alkoxyketones has been constructed which show strong inhibitory activity against the cysteine protease, cathepsin K (EC 3.4.22.38). 相似文献
6.
Heterogeneous duplications in patients with Pelizaeus-Merzbacher disease suggest a mechanism of coupled homologous and nonhomologous recombination 下载免费PDF全文
Woodward KJ Cundall M Sperle K Sistermans EA Ross M Howell G Gribble SM Burford DC Carter NP Hobson DL Garbern JY Kamholz J Heng H Hodes ME Malcolm S Hobson GM 《American journal of human genetics》2005,77(6):966-987
We describe genomic structures of 59 X-chromosome segmental duplications that include the proteolipid protein 1 gene (PLP1) in patients with Pelizaeus-Merzbacher disease. We provide the first report of 13 junction sequences, which gives insight into underlying mechanisms. Although proximal breakpoints were highly variable, distal breakpoints tended to cluster around low-copy repeats (LCRs) (50% of distal breakpoints), and each duplication event appeared to be unique (100 kb to 4.6 Mb in size). Sequence analysis of the junctions revealed no large homologous regions between proximal and distal breakpoints. Most junctions had microhomology of 1-6 bases, and one had a 2-base insertion. Boundaries between single-copy and duplicated DNA were identical to the reference genomic sequence in all patients investigated. Taken together, these data suggest that the tandem duplications are formed by a coupled homologous and nonhomologous recombination mechanism. We suggest repair of a double-stranded break (DSB) by one-sided homologous strand invasion of a sister chromatid, followed by DNA synthesis and nonhomologous end joining with the other end of the break. This is in contrast to other genomic disorders that have recurrent rearrangements formed by nonallelic homologous recombination between LCRs. Interspersed repetitive elements (Alu elements, long interspersed nuclear elements, and long terminal repeats) were found at 18 of the 26 breakpoint sequences studied. No specific motif that may predispose to DSBs was revealed, but single or alternating tracts of purines and pyrimidines that may cause secondary structures were common. Analysis of the 2-Mb region susceptible to duplications identified proximal-specific repeats and distal LCRs in addition to the previously reported ones, suggesting that the unique genomic architecture may have a role in nonrecurrent rearrangements by promoting instability. 相似文献
7.
The genera Protoperidinium Bergh, Diplopsalis Bergh, and Preperidinium Mangin, comprised of species of marine, thecate, heterotrophic dinoflagellates in the family Protoperidinaceae Balech, have had a confused taxonomic history. To elucidate the validity of morphological groupings within the Protoperidinium and diplopsalids, and to determine the evolutionary relationships between these and other dinoflagellates, we undertook a study of molecular phylogeny using the D1–D3 domains of the large subunit (LSU) of the rDNA. Based on morphology, the 10 Protoperidinium species examined belonged to three subgenera and five morphological sections. Two diplopsalid species were also included. Single‐cell PCR, cloning, and sequencing revealed a high degree of intraindividual sequence variability in the LSU rDNA. The genus Protoperidinium appeared to be recently divergent in all phylogenetic analyses. In maximum parsimony and neighbor joining analyses, Protoperidinium formed a monophyletic group, evolving from diplopsalid dinoflagellates. In maximum likelihood and Bayesian analyses, however, Protoperidinium was polyphyletic, as the lenticular, diplopsalid heterotroph, Diplopsalis lenticula Bergh, was inserted within the Protoperidinium clade as basal to Protoperidinium excentricum (Paulsen) Balech, and Preperidinium meunieri (Pavillard) Elbrächter fell within a separate clade as a sister to the Oceanica and Protoperidinium steidingerae Balech. In all analyses, the Protoperidinium were divided into two major clades, with members in the Oceanica group and subgenus Testeria in one clade, and the Excentrica, Conica, Pellucida, Pyriforme and Divergens sections in the other clade. The LSU rDNA molecular phylogeny supported the historical morphologically determined sections, but not a simple morphology based model of evolution based on thecal plate shape. 相似文献
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Ian P. Holmes Richard J. Blunt Olivier E. Lorthioir Stephen M. Blowers Andy Gribble Andrew H. Payne Ian G. Stansfield Martyn Wood Patrick M. Woollard Charlie Reavill Claire M. Howes Fabrizio Micheli Romano Di Fabio Daniele Donati Silvia Terreni Dieter Hamprecht Luca Arista Angela Worby Steve P. Watson 《Bioorganic & medicinal chemistry letters》2010,20(6):2013-2016
The identification of a highly selective D2 partial agonist, D3 antagonist tool molecule which demonstrates high levels of brain exposure and selectivity against an extensive range of dopamine, serotonin, adrenergic, histamine, and muscarinic receptors is described. 相似文献