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Maneesakorn P An R Daneshvar H Taylor K Bai X Adams BJ Grewal PS Chandrapatya A 《Molecular phylogenetics and evolution》2011,59(2):271-280
Mutualistic association between entomopathogenic Photorhabdus bacteria and Heterorhabditis nematodes represents one of the emerging model systems in symbiosis studies, yet little is known about this partnership from a coevolutionary perspective. Herein, we investigated phylogenetic and cophylogenetic relationships of Heterorhabditis and Photorhabdus strains using molecular markers Internal Transcribed Spacer and gyrase B gene sequences, respectively. The phylogenies presented consistent, well supported, monophyletic groups in the parsimonious and likelihood analyses for both the nematode and bacterial strains and supported the placement of currently recognized taxa, from which a potentially new Heterorhabditis species represented by a Thailand strain MP68 was identified. While the nematode strains with distant geographic distributions showed no detectable phylogenetic divergence within H. bacteriophora or H. georgiana monophyletic groups, their respective symbiotic bacteria speciated into two Photorhabdus species: P. luminescens and P. temperata, indicating the occurrence of duplication. Although such evolutionary process reduces the phylogenetic congruence between Heterorhabditis nematodes and Photorhabdus bacteria, global cophylogenetic tests using ParaFit detected a highly significant correlation between the two phylogenies (ParaFitGlobal = 0.001). Further, the associations between H. zealandica, H. indica and H. megidis strains and their symbiotic bacteria exhibited significant contribution to the overall cophylogenetic structure. Overall, this study reveals evidence of coevolution between Photorhabdus bacteria and Heterorhabditis nematodes and provides a framework for further examination of the evolution of these associations. 相似文献
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Wanida Donpunha Upa Kukongviriyapan Kwanjit Sompamit Poungrat Pakdeechote Veerapol Kukongviriyapan Patchareewan Pannangpetch 《Biometals》2011,24(1):105-115
Cadmium (Cd) is one of the most important environmental pollutants that cause a number of adverse health effects in humans
and animals. Recent studies have shown that Cd-induced oxidative damage within the vascular tissues results in vascular dysfunction.
The current study was aimed to investigate whether ascorbic acid could protect against Cd-induced vascular dysfunction in
mice. Male ICR mice were received CdCl2 (100 mg/l) via drinking water for 8 weeks alone or received ascorbic acid supplementation at doses of 50 and 100 mg/kg/day
for every other day. Results showed that Cd administration increased arterial blood pressure and blunted the vascular responses
to vasoactive agents. These alterations were related to increased superoxide production in thoracic aorta, increased urinary
nitrate/nitrite, increased plasma protein carbonyl, elevated malondialdehyde (MDA) concentrations in plasma and tissues, decreased
blood glutathione (GSH), and increased Cd contents in blood and tissues. Ascorbic acid dose-dependently normalized the blood
pressure, improved vascular reactivities to acetylcholine (ACh), phenylephrine (Phe) and sodium nitroprusside (SNP). These
improvements were associated with significant suppression of oxidant formation, prevention of GSH depletion, and partial reduction
of Cd contents in blood and tissues. The findings in this study provide the first evidence in pharmacological effects of ascorbic
acid on alleviation of oxidative damage and improvement of vascular function in a mouse model of Cd-induced hypertension and
vascular dysfunction. Moreover, our study suggests that dietary supplementation of ascorbic acid may provide beneficial effects
by reversing the oxidative stress and vascular dysfunction in Cd-induced toxicity. 相似文献
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