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371.
Did RNA editing in plant organellar genomes originate under natural selection or through genetic drift? 总被引:1,自引:0,他引:1
Background
The C↔U substitution types of RNA editing have been observed frequently in organellar genomes of land plants. Although various attempts have been made to explain why such a seemingly inefficient genetic mechanism would have evolved, no satisfactory explanation exists in our view. In this study, we examined editing patterns in chloroplast genomes of the hornwort Anthoceros formosae and the fern Adiantum capillus-veneris and in mitochondrial genomes of the angiosperms Arabidopsis thaliana, Beta vulgaris and Oryza sativa, to gain an understanding of the question of how RNA editing originated. 相似文献372.
Anne Caroline Wiik Ernst-Otto Ropstad Ellen Bjerkås Frode Lingaas 《BMC veterinary research》2008,4(1):23
Background
A genetic study was performed to identify candidate genes associated with day blindness in the standard wire haired dachshund. Based on a literature review of diseases in dogs and human with phenotypes similar to day blindness, ten genes were selected and evaluated as potential candidate genes associated with day blindness in the breed.Results
Three of the genes, CNGB3, CNGA3 and GNAT2, involved in cone degeneration and seven genes and loci, ABCA4, RDH5, CORD8, CORD9, RPGRIP1, GUCY2D and CRX, reported to be involved in cone-rod dystrophies were studied. Polymorphic markers at each of the candidate loci were studied in a family with 36 informative offspring. The study revealed a high frequency of recombinations between the candidate marker alleles and the disease.Conclusion
Since all of the markers were at the exact position of the candidate loci, and several recombinations were detected for each of the loci, all ten genes were excluded as causal for this canine, early onset cone-rod dystrophy. The described markers may, however, be useful to screen other canine resource families segregating eye diseases for association to the ten genes.373.
Ravinder Kaur Grewal Monika Lulsdorf Janine Croser Sergio Ochatt Albert Vandenberg Thomas D. Warkentin 《Plant cell reports》2009,28(8):1289-1299
This is the first report on the production of double-haploid chickpea embryos and regenerated plants through anther culture
using Canadian cultivar CDC Xena (kabuli) and Australian cultivar Sonali (desi). Maximum anther induction rates were 69% for
Sonali and 63% for CDC Xena. Under optimal conditions, embryo formation occurred within 15–20 days of culture initiation with
2.3 embryos produced per anther for CDC Xena and 2.0 embryos per anther for Sonali. For anther induction, the following stress
treatments were used: (1) flower clusters were treated at 4°C for 4 days, (2) anthers were subjected to electric shock treatment
of three exponentially decaying pulses of 50–400 V with 25 μF capacitance and 25 Ω resistance, (3) anthers were centrifuged
at 168–1,509g for 2–15 min, and finally (4) anthers were cultured for 4 days in high-osmotic pressure (563 mmol) liquid medium. Anthers
were then transferred to a solid embryo development medium and, 15–20 days later, embryo development was observed concomitant
with a small amount of callus growth of 0.1–3 mm. Anther-derived embryos were regenerated on plant regeneration medium. Electroporation
treatment of anthers enhanced root formation, which is often a major hurdle in legume regeneration protocols. Cytological
studies using DAPI staining showed a wide range of ploidy levels from haploid to tetraploid in 10–30-day-old calli. Flow cytometric
analysis of calli, embryos and regenerated plants showed haploid profiles and/or spontaneous doubling of the chromosomes during
early regeneration stages. 相似文献
374.
CHROMagar has been reported to be useful for the rapid and accurate identification of Candida species. We tested 135 isolates of Candida species isolated from oropharyngeal candidiasis in HIV patients and found that it was useful in the presumptive identification
of Candida albicans and Candida krusei. Occasional strains of C. tropicalis produced colonies with a greenish tinge making it difficult to differentiate from C. albicans. 相似文献
375.
Shunhui Wei Stephanie Li‐Ying Soh Julia Xia Wei‐Yi Ong Zhiping P. Pang Weiping Han 《Journal of neurochemistry》2014,129(2):328-338
Gain‐of‐toxic‐function mutations in Seipin (Asparagine 88 to Serine (N88S) and Serine 90 to Leucine (S90L) mutations, both of which disrupt the N‐glycosylation) cause autosomal dominant motor neuron diseases. However, the mechanism of how these missense mutations lead to motor neuropathy is unclear. Here, we analyze the impact of disruption of N‐glycosylation of Seipin on synaptic transmission by over‐expressing mutant Seipin in cultured cortical neurons via lentiviral infection. Immunostaining shows that over‐expressed Seipin is partly colocalized with synaptic vesicle marker synaptophysin. Electrophysiological recordings reveal that the Seipin mutation significantly decreases the frequency, but not the amplitudes of miniature excitatory post‐synaptic currents and miniature inhibitory post‐synaptic currents. The amplitude of both evoked excitatory post‐synaptic currents and inhibitory post‐synaptic current is also compromised by mutant Seipin over‐expression. The readily releasable pool and vesicular release probability of synaptic vesicles are both altered in neurons over‐expressing Seipin‐N88S, whereas neither γ‐amino butyric acid (GABA) nor α‐Amino‐3‐hydroxy‐5‐methyl‐4‐ isoxazolepropionic acid (AMPA) induced whole cell currents are affected. Moreover, electron microscopy analysis reveals decreased number of morphologically docked synaptic vesicles in Seipin‐N88S‐expressing neurons. These data demonstrate that Seipin‐N88S mutation impairs synaptic neurotransmission, possibly by regulating the priming and docking of synaptic vesicles at the synapse.
376.
Jérôme Dumur Gérard Branlard Anne-Marie Tanguy Mireille Dardevet Olivier Coriton Virginie Huteau Jocelyne Lemoine Joseph Jahier 《Planta》2009,231(1):57-65
In an attempt to improve the bread-making quality within hexaploid wheat by elaborating novel high-molecular weight glutenin
subunits (HMW-GS) combinations useful in wheat-breeding programmes, a 1A chromosome fragment carrying the Glu-A1 locus encoding the subunit Ax2*, was translocated to the long arm of chromosome 1D. The partially isohomoeoallelic line,
designated RR239, had a meiotic behaviour as regular as cv. Courtot. It was characterised using genomic in situ hybridization
and microsatellite markers as well as biochemical and proteomic approaches. The translocated 1D chromosome had an interstitial
1AL segment representing in average 30% of the recombinant arm length that was confirmed by molecular analysis. The genetic
length of the removed segment in chromosome 1DL was estimated to be at least 51 cM, and that of the interstitial 1AL translocation
to be at least 33 cM. Proteome analysis performed on total endosperm proteins revealed variation in amounts, 8 spots and 1
spot being up- and downregulated, respectively. Quantitative variations in HMW-GS were observed for the Glu-A1 (Ax2*) and Glu-B1 (Bx7 + By8) loci in response to duplication of the Glu-A1 locus. 相似文献
377.
Varisa Pongrakhananon Ubonthip Nimmannit Sudjit Luanpitpong Yon Rojanasakul Pithi Chanvorachote 《Apoptosis : an international journal on programmed cell death》2010,15(5):574-585
Anoikis, an apoptosis triggered by loss of cell anchorage, has been shown to be a principal mechanism of inhibition of tumor
metastasis. Recently, anti-apoptotic Bcl-2 and Cav-1 proteins have been demonstrated to be highly associated with tumor metastasis
and apoptosis resistance. Curcumin, a major active component of turmeric, Curcuma longa, has been shown to inhibit neoplastic evolution and tumor progression; however, the underlying mechanisms are unclear. In
this study, we investigated the effect of curcumin on cell anoikis as a possible mechanism of anti-tumorigenic action of curcumin,
and evaluated the potential role of Bcl-2 and Cav-1 in this process. Our results showed that ectopic expression of either
Bcl-2 or Cav-1 induced anoikis resistance of lung carcinoma H460 cells. Curcumin downregulated Bcl-2 protein during anoikis
and sensitized the cells to detachment-induced apoptosis, whereas it had no significant effect on Cav-1 protein expression.
Bcl-2 down-regulation as well as anoikis enhancement by curcumin were inhibited by superoxide anion scavenger, Mn(III)tetrakis(4-benzoic
acid) porphyrin chloride, but were unaffected by other ROS scavengers including catalase and deferoxamine, suggesting that
superoxide anion is a key player in the downregulation of Bcl-2 by curcumin. Furthermore, we provided evidence that curcumin
decreased Bcl-2 level through ubiquitin-proteasomal degradation which sensitized cells to detachment-induced apoptosis. These
findings indicate a novel pathway for curcumin regulation of Bcl-2 and provide a key mechanism of anoikis regulation that
may be exploited for metastatic cancer treatment. 相似文献
378.
379.
To investigate the evolutionary history of mesoderm in the bilaterian lineage, we are studying mesoderm development in the
polychaete annelid, Capitella sp. I, a representative lophotrochozoan. In this study, we focus on the Twist and Snail families as candidate mesodermal
patterning genes and report the isolation and in situ expression patterns of two twist homologs (CapI-twt1 and CapI-twt2) and two snail homologs (CapI-sna1 and CapI-sna2) in Capitella sp. I. CapI-twt1 is expressed in a subset of mesoderm derivatives during larval development, while CapI-twt2 shows more general mesoderm expression at the same stages. Neither twist gene is detected before the completion of gastrulation. The two snail genes have very distinct expression patterns. At cleavage and early gastrula stages, CapI-sna1 is broadly expressed in precursors of all three germ layers and becomes restricted to cells around the closing blastopore
during late gastrulation; CapI-sna2 expression is not detected at these stages. After gastrulation, both snail genes are expressed in the developing central nervous system (CNS) at stages when neural precursor cells are internalized,
and CapI-sna1 is also expressed laterally within the segmental mesoderm. Based on the expression patterns in this study, we suggest a putative
function for Capitella sp. I twist genes in mesoderm differentiation and for snail genes in regulating CNS development and general cell migration during gastrulation.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
380.
Replicate harvest simulations were conducted in a large natural population of Panax quinquefolius L.␣(Araliaceae) to determine the selective effects of harvest. We investigated how minimum size requirements and the influence
of size on apparency to human harvesters could result in preferential removal of large plants. To determine which plants were
encountered in the large population, harvesters were tracked using GPS as they searched for every legally harvestable, adult
plant they could find. Plants were assigned stage-specific fitness measures based on their contributions to population growth
rate (λ) under three demographically based harvest regimes: no harvest, harvest and harvest removing seeds. Plant size was
codified into a size-index equal to the product of total leaf area and stem height. Heterogeneity of slopes was tested to
determine if the selection gradients (β) describing the relationship between fitness and size varied among the three harvest
regimes. Harvest differentially reduced the fitness of larger plants in one of four individual harvest simulations. The combined
harvest simulation significantly altered the selection regime for size in the population of juvenile and adult (harvestable)
plants. Seed removal by harvesters intensified fitness declines for larger plants. Because larger plants contribute most to
population growth, the selective effects of harvest could result in a shift in the evolutionary dynamics of this species with
significant conservation implications. 相似文献