The mean time to resolution of gene duplication (Tr) is studied in this paper under the double null recessive (DNR) and haplo-insufficient (HI) models within the same analytical
and simulation framework. We show that when population size is not too small (more precisely Nμ > 0.1), Tr for unlinked duplication is usually larger than that for linked and Tr for unlinked duplication under the HI model might be greatly prolonged, which were consistent with previous observations.
Furthermore, by analytical approach we here indicate the primary underlying mechanism is that the frequency of the original
(or wild-type) chromosomal haplotype of the linked duplication decreases nearly exponential to zero with time while that of
the unlinked decreases quickly to an quasi-equilibrium; and this phenomenon is particularly profound under the HI model, because
the quasi-equilibrium frequency of the original chromosomal haplotype (x0) under the HI model is higher than that under the DNR model. These results suggest that recombination and HI model might
jointly contribute to the marked prolongation of Tr even in a modest population. The prolonged Tr and higher quasi-equilibrium frequency of the original allele at both duplicated loci might have offered more opportunities
for the emergence of novel genes. 相似文献
The aim of this study was to evaluate the impact of zeolite powders on feasibility of rapid aerobic granulation in the column-type sequencing batch reactors. After 90 days' operation, aerobic granular sludge was formed in both reactors by altering influent chemical oxygen demand/nitrogen (COD/N) ratios. R1 with zeolite powders had better removal capabilities of COD and total nitrogen than R2, which was without zeolite powders. Mixed liquor volatile suspended solid concentrations of the two reactors were 7.36 and 5.45 g/L, while sludge volume index (SVI30) values were 34.9 and 47.9 mg/L, respectively. The mean diameters of aerobic granular sludge in the above two reactors were 2.5 and 1.5 mm, respectively. Both reactors achieved the largest simultaneous nitrification and denitrification (SND) efficiency at an influent COD/N ratio of 8; however, R1 exhibited more excellent SND efficiency than R2. The obtained results could provide a novel technique for rapid aerobic granulation and N removal simultaneously, especially when treating nitrogen-rich industrial wastewater. 相似文献
Increasing reports suggest that deregulated microRNAs (miRNAs) might provide novel therapeutic targets for cancers. However, the expression and function of miR-300 in osteosarcoma is still unknown. In our study, we found that the expression of miR-300 was up-regulated in osteosarcoma tissues and cells compared with paired adjacent non-tumor bone tissues and osteoblastic cells using RT-qPCR. The enforced expression of miR-300 could promote cell proliferation, invasion and epithelial-mesenchymal transition (EMT). Moreover, we identified that bromodomain-containing protein 7 (BRD7), a new tumor suppressor gene, was a direct target of miR-300. Ectopic expression of BRD7 could significantly inhibit miR-300-promoted proliferation, invasion and EMT. Therefore, our results identify an important role for miR-300 in osteosarcoma through regulating BRD7 expression. 相似文献
Acute respiratory distress syndrome (ARDS) is a contemporary term incorporating the historic ‘acute lung injury’ and the colloquial term ‘shock lung’. ARDS remains a serious and enigmatic human disease, causing significant mortality. The mechanisms involved at the alveolar cell/capillary endothelial interface have been explored but to date we lack clarity on the role of intracellular calcium ([Ca2+]i) fluxes across this interface. To explore the mechanisms of Ca2+ induced inflammatory reaction in epithelial cells and pulmonary microvascular endothelial cells (HMVEC) located at the two sides of blood-air barrier, lung epithelial A549 and HMVEC cells were treated with LPS. Our results demonstrated that LPS evoked the increase of [Ca2+]i, TNF-α and IL-8 in both cells types. The [Ca2+]i increases involved intracellular but not extracellular Ca2+ sources in A549, but both intracellular and extracellular Ca2+ sources in HMVEC cells. The effects of LPS on both cells types were completely inhibited by the combination of LPS and CaSR-targeted siRNA. Furthermore, LPS-inhibited cell proliferations were significantly reversed by the combined treatment. Therefore, LPS induced different mechanisms of [Ca2+]i increase during the activation of CaSR in A549 and HMVEC cells, which translates into functional outputs related to ARDS. 相似文献