instruction:
Given a passage with a context and an answer, construct a question on the basis of the information present in the passage. Construct the question in such a way that (i) it is unambiguous, (ii) it is answerable from the passage, (iii) its answer is unique (iv) it answer uses text phrases from the passage. Avoid creating questions that (i) can't be answered correctly without actually understanding the passage and (ii) uses the same words or phrases given in the passage.
question:
Context: Brassica napus (AACC) is self-compatible, although its ancestor species Brassica rapa (AA) and Brassica oleracea (CC) are self-incompatible. Most B.napus accessions have dominant self-compatibility (SC) resulting from an insertion of 3.6 kb in the promoter region of BnSCR-1 on the A genome, while recessive SC in B.napus has rarely been observed. Expression and cloning of SRK and SCR genes and genetic analysis were carried out to dissect bases of recessive SC in B.napus.', 'Eleven accessions were screened to identify stable recessive SC and had the S genotype BnS-7 on the A genome and BnS-6 on the C genome similarly to BrS-29 and BoS-15, respectively. In eight SC accessions, BnSCR-7 and BnSCR-6 were nearly undetectable and harbored no structural mutations in the promoters, while SRK genes were expressed at normal levels and contained intact CDS, with the exception of BnSRK-7 in line C32. SRK and SCR genes were expressed normally but their CDSs had no mutations in three SC accessions. In self-incompatible S-1300 and 11 F1 hybrids, SRK genes and BnSCR-1300 transcripts were present at high levels, while expression of the BnSCR-7 and BnSCR-6 were absent. Plants of S genotype S1300S1300 were completely SI, while SI phenotypes of SBnS-7SBnS-7 and S1300SBnS-7 plants were segregated in BC1 and F2 populations.
Answer: The recessive SC in eight accessions is caused by the loss of function of BnSCR-7 and BnSCR-6 in pollen. Translational repression contributes to the recessive SC in three accessions, whose SRK and SCR genes were expressed normally and had identical CDSs to BrS-29 or BoS-15. SI in 11 F1 hybrids relies on the expression of BnSCR-1300 rather than SRK genes. Other factor(s) independent of the S locus are involved in recessive SC. Therefore, diverse causes underlie recessive SC in B. napus, yielding insight into these complex mechanisms.
answer:
Do gene expression and genetic analysis reveal diverse causes of recessive self-compatibility in Brassica napus L?


question:
Context: Magnetic fields have been shown to affect cell proliferation and growth factor expression in cultured cells. Although the activation of endorphin systems is a recurring motif among the biological events elicited by magnetic fields, compelling evidence indicating that magnetic fields may modulate opioid gene expression is still lacking. We therefore investigated whether extremely low frequency (ELF) pulsed magnetic fields (PMF) may affect opioid peptide gene expression and the signaling pathways controlling opioid peptide gene transcription in the adult ventricular myocyte, a cell type behaving both as a target and as a source for opioid peptides.', 'Prodynorphin gene expression was investigated in adult rat myocytes exposed to PMF by the aid of RNase protection and nuclear run-off transcription assays. In PMF-exposed nuclei, nuclear protein kinase C (PKC) activity was followed by measuring the phosphorylation rate of the acrylodan-labeled MARCKS peptide. The effect of PMF on the subcellular distribution of different PKC isozymes was assessed by immunoblotting. A radioimmunoassay procedure coupled to reversed-phase high performance liquid chromatography was used to monitor the expression of dynorphin B.', 'Here, we show that PMF enhanced myocardial opioid gene expression and that a direct exposure of isolated myocyte nuclei to PMF markedly enhanced prodynorphin gene transcription, as in the intact cell. The PMF action was mediated by nuclear PKC activation but occurred independently from changes in PKC isozyme expression and enzyme translocation. PMF also led to a marked increase in the synthesis and secretion of dynorphin B.
Answer: The present findings demonstrate that an opioid gene is activated by myocyte exposure to PMF and that the cell nucleus and nuclear embedded PKC are a crucial target for the PMF action. Due to the wide ranging importance of opioid peptides in myocardial cell homeostasis, the current data may suggest consideration for potential biological effects of PMF in the cardiovascular system.
answer:
Do elf-pulsed magnetic fields modulate opioid peptide gene expression in myocardial cells?


question:
Context: A transgenic mouse model has revealed parameters of the angiogenic switch during multistep tumorigenesis of pancreatic islets, and demonstrated efficacy of antiangiogenic therapies. Pericytes have been revealed as functionally important for tumor neovasculature, using kinase inhibitors targeting their platelet-derived growth factor receptors (PDGFRs). Additionally, vascular endothelial growth factor receptor (VEGFR) inhibitors and metronomic chemotherapy show modest benefit against early- but not late-stage disease.', 'Seeking to improve efficacy against otherwise intractable end-stage pancreatic islet tumors, two receptor tyrosine kinase inhibitors, imatinib and SU11248, were used to disrupt PDGFR-mediated pericyte support of tumor endothelial cells in concert with maximum-tolerated dose (MTD) or metronomic chemotherapy and/or VEGFR inhibition.', 'Imatinib, despite equivocal efficacy as monotherapy, reduced pericyte coverage of tumor vessels and enhanced efficacy in combination with metronomic chemotherapy or VEGFR inhibition. A regimen involving all three was even better. MTD using cyclophosphamide caused transitory regression, but then rapid regrowth, in contrast to metronomic cyclophosphamide plus imatinib, which produced stable disease. The MTD regimen elicited apoptosis of tumor cells but not endothelial cells, whereas the other regimens increased endothelial cell apoptosis concordant with efficacy. A "chemo-switch" protocol, involving sequential MTD and then metronomic chemotherapy, overlaid with multitargeted inhibition of PDGFR and VEGFR, gave complete responses and unprecedented survival advantage in this model.
Answer: This study demonstrates a potentially tractable clinical strategy in a stringent preclinical model, wherein standard-of-care chemotherapy is followed by a novel maintenance regimen: PDFGR is targeted to disrupt pericyte support, while metronomic chemotherapy and/or VEGFR inhibitors target consequently sensitized endothelial cells, collectively destabilizing pre-existing tumor vasculature and inhibiting ongoing angiogenesis.
answer:

Is a multitargeted , metronomic , and maximum-tolerated dose `` chemo-switch '' regimen antiangiogenic , producing objective responses and survival benefit in a mouse model of cancer?