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71.
Phylogenetic utility of the nuclear gene arginine decarboxylase: an example from Brassicaceae 总被引:10,自引:2,他引:8
Arginine decarboxylase (ADC) is an important enzyme in the production of
putrescine and polyamines in plants. It is encoded by a single or low-copy
nuclear gene that lacks introns in sequences studied to date. The rate of
Adc amino acid sequence evolution is similar to that of ndhF for the
angiosperm family studied. Highly conserved regions provide several target
sites for PCR priming and sequencing and aid in nucleotide and amino acid
sequence alignment across a range of taxonomic levels, while a variable
region provides an increased number of potentially informative characters
relative to ndhF for the taxa surveyed. The utility of the Adc gene in
plant molecular systematic studies is demonstrated by analysis of its
partial nucleotide sequences obtained from 13 representatives of
Brassicaceae and 3 outgroup taxa, 2 from the mustard oil clade (order
Capparales) and 1 from the related order Malvales. Two copies of the Adc
gene, Adc1 and Adc2, are found in all members of the Brassicaceae studied
to data except the basal genus Aethionema. The resulting Adc gene tree
provides robust phylogenetic data regarding relationships within the
complex mustard family, as well as independent support for proposed tribal
realignments based on other molecular data sets such as those from
chloroplast DNA.
相似文献
72.
The formation of a blastema during regeneration of an axolotl limb involves important changes in the behavior and function of cells at the site of injury. One of the earliest events is the formation of the wound epithelium and subsequently the apical epidermal cap, which involves in vivo dedifferentiation that is controlled by signaling from the nerve. We have investigated the role of epigenetic modifications to the genome as a possible mechanism for regulating changes in gene expression patterns of keratinocytes of the wound and blastema epithelium that are involved in regeneration. We report a modulation of the expression DNMT3a, a de novo DNA methyltransferase, within the first 72 hours post injury that is dependent on nerve signaling. Treatment of skin wounds on the upper forelimb with decitabine, a DNA methyltransferase inhibitor, induced changes in gene expression and cellular behavior associated with a regenerative response. Furthermore, decitabine-treated wounds were able to participate in regeneration while untreated wounds inhibited a regenerative response. Elucidation of the specific epigenetic modifications that mediate cellular dedifferentiation likely will lead to insights for initiating a regenerative response in organisms that lack this ability. 相似文献
73.
Md. Mahiuddin Ahmed A. Ranjitha Dhanasekaran Aaron Block Suhong Tong Alberto C. S. Costa Melissa Stasko Katheleen J. Gardiner 《PloS one》2015,10(3)
Down syndrome (DS) is caused by an extra copy of human chromosome 21 (Hsa21). Although it is the most common genetic cause of intellectual disability (ID), there are, as yet, no effective pharmacotherapies. The Ts65Dn mouse model of DS is trisomic for orthologs of ∼55% of Hsa21 classical protein coding genes. These mice display many features relevant to those seen in DS, including deficits in learning and memory (L/M) tasks requiring a functional hippocampus. Recently, the N-methyl-D-aspartate (NMDA) receptor antagonist, memantine, was shown to rescue performance of the Ts65Dn in several L/M tasks. These studies, however, have not been accompanied by molecular analyses. In previous work, we described changes in protein expression induced in hippocampus and cortex in control mice after exposure to context fear conditioning (CFC), with and without memantine treatment. Here, we extend this analysis to Ts65Dn mice, measuring levels of 85 proteins/protein modifications, including components of MAP kinase and MTOR pathways, and subunits of NMDA receptors, in cortex and hippocampus of Ts65Dn mice after failed learning in CFC and after learning was rescued by memantine. We show that, compared with wild type littermate controls, (i) of the dynamic responses seen in control mice in normal learning, >40% also occur in Ts65Dn in failed learning or are compensated by baseline abnormalities, and thus are considered necessary but not sufficient for successful learning, and (ii) treatment with memantine does not in general normalize the initial protein levels but instead induces direct and indirect responses in approximately half the proteins measured and results in normalization of the endpoint protein levels. Together, these datasets provide a first view of the complexities associated with pharmacological rescue of learning in the Ts65Dn. Extending such studies to additional drugs and mouse models of DS will aid in identifying pharmacotherapies for effective clinical trials. 相似文献
74.
Renia Coghlan Elizabeth Gardiner Farhana Amanullah Chikwe Ihekweazu Rina Triasih Malgorzata Grzemska Charalambos Sismanidis 《PloS one》2015,10(10)
MethodologyExploratory assessments were carried out in Indonesia, Nigeria and Pakistan, reaching a range of facility types in two selected areas of each country. Record reviews and interviews of healthcare providers were carried out to assess numbers of unreported paediatric TB cases, diagnostic pathways followed and treatment regimens prescribed.
Main Findings
A total of 985 unreported diagnosed paediatric TB cases were identified over a three month period in 2013 in Indonesia from 64 facilities, 463 in Pakistan from 35 facilities and 24 in Nigeria from 20 facilities. These represent an absolute additional annualised yield to 2013 notifications reported to WHO of 15% for Indonesia, 2% for Nigeria and 7% for Pakistan. Only 12% of all facilities provided age and sex-disaggregated data. Findings highlight the challenges of confirming childhood TB. Diagnosis patterns in Nigeria highlight a very low suspicion for childhood TB. Providers note the need for paediatric medicines aligned to WHO recommendations.Conclusion: How Market Data Can Support Better Public Health Interventions
This study emphasises the impact of incomplete reporting on the estimation of disease burden and potential market size of paediatric TB medicines. Further studies on “hubs” (facilities treating large numbers of childhood TB cases) will improve our understanding of the epidemic, support introduction efforts for new treatments and better measure markets for new paediatric medicines. 相似文献75.
We have modified and optimized the technique of organotypic slice culture in order to study the mechanisms regulating growth and pattern formation in regenerating axolotl limb blastemas. Blastema cells maintain many of the behaviors that are characteristic of blastemas in vivo when cultured as slices in vitro, including rates of proliferation that are comparable to what has been reported in vivo. Because the blastema slices can be cultured in basal medium without fetal bovine serum, it was possible to test the response of blastema cells to signaling molecules present in serum, as well as those produced by nerves. We also were able to investigate the response of blastema cells to experimentally regulated changes in BMP signaling. Blastema cells responded to all of these signals by increasing the rate of proliferation and the level of expression of the blastema marker gene, Prrx-1. The organotypic slice culture model provides the opportunity to identify and characterize the spatial and temporal co-regulation of pathways in order to induce and enhance a regenerative response. 相似文献
76.
77.
Competitive exclusion as a mode of action of a novel Bacillus cereus aquaculture biological agent 总被引:1,自引:0,他引:1
R. Lalloo G. Moonsamy S. Ramchuran J. Görgens N. Gardiner 《Letters in applied microbiology》2010,50(6):563-570
Aims: To determine the contribution of potential modes of action of a Bacillus cereus aquaculture biological control agent in inhibition of the fish pathogen, Aeromonas hydrophila. Methods and Results: When B. cereus was tested in plate well inhibition studies, no production of antimicrobial compounds was detected. Bacillus cereus had a high growth rate (0·96 h?1), whereas Aer. hydrophila concentration decreased by c. 70% in co‐culture experiments. In nutrient limitation studies, B. cereus had a significantly higher growth rate when cultured under glucose (P < 0·05) and iron (P < 0·01) limitation in comparison with Aer. hydrophila. Bacillus cereus glucose (0·30 g l?1 h?1) and iron (0·60 mg l?1 h?1) uptake rates were also significantly higher (P < 0·01) than the Aer. hydrophila glucose (0·14 g l?1 h?1) and iron (0·43 mg l?1 h?1) uptake rates. Iron uptake was facilitated by siderophore production shown in time profile studies where relative siderophore production was c. 60% through the late exponential and sporulation phases. Conclusions: Competitive exclusion by higher growth rate, competition for organic carbon and iron, facilitated by siderophore production, could be identified as mechanisms of pathogen growth inhibition by B. cereus. Significance and Impact of the Study: This study is the first elucidation of the mechanism of action of our novel B. cereus biological agent in growth attenuation of pathogenic Aer. hydrophila. This study enhances the application knowledge and attractiveness for adoption of B. cereus NRRL 100132 for exploitation in aquaculture. 相似文献
78.
79.
Donald M Gardiner Kemal Kazan Sebastien Praud Francois J Torney Anca Rusu John M Manners 《BMC plant biology》2010,10(1):289
Background
The fungal pathogen Fusarium graminearum causes Fusarium Head Blight (FHB) disease on wheat which can lead to trichothecene mycotoxin (e.g. deoxynivalenol, DON) contamination of grain, harmful to mammalian health. DON is produced at low levels under standard culture conditions when compared to plant infection but specific polyamines (e.g. putrescine and agmatine) and amino acids (e.g. arginine and ornithine) are potent inducers of DON by F. graminearum in axenic culture. Currently, host factors that promote mycotoxin synthesis during FHB are unknown, but plant derived polyamines could contribute to DON induction in infected heads. However, the temporal and spatial accumulation of polyamines and amino acids in relation to that of DON has not been studied. 相似文献80.
Gyrodinium estuariale Hulburt has ultrastructural features typical for a dinoflagellate including a particularly well developed pusule and numerous prominent trichocysts. The amphiesma is relatively simple with thecal vesicles containing thecal membranes. The epicone is embellished with two concentric raised ridges reminiscent of the form typical for more heavily thecate genera. 相似文献