ABSTRACT
In this study, the nitrate transporter gene CmNRT1 was isolated from the chrysanthemum variety 'Nannongxuefeng'. The full-length cDNA contains an open reading frame of 1761 bp encoding 587 residues. Using qRT-PCR, we found that CmNRT1 was induced by 10 mM NO3(-) in roots and shoots. Two Arabidopsis thaliana transgenic plants expressing CmNRT1 were selected for functional analyses. Root (15)N influx in wild-type and transgenic A. thaliana lines under 10 or 0.2 mM (15)NO3 was tested. Our results indicate that CmNRT1 encodes a constitutive component for a low-affinity transporter.
Subject(s)
Anion Transport Proteins/metabolism , Chrysanthemum/metabolism , Plant Proteins/metabolism , Plant Roots/metabolism , Amino Acid Sequence , Anion Transport Proteins/chemistry , Anion Transport Proteins/genetics , Anion Transport Proteins/isolation & purification , Arabidopsis/genetics , Molecular Sequence Data , Nitrate Transporters , Phylogeny , Plant Proteins/chemistry , Plants, Genetically Modified , Sequence AlignmentABSTRACT
BACKGROUND: Sometimes the diagnosis of recurrent cancer in patients with a previous malignancy can be challenging. This prospective cohort study assessed the clinical utility of (18)F-fluorodeoxyglucose positron-emission tomography-computed tomography ((18)F-FDG PET-CT) in the diagnosis of clinically suspected recurrence of cancer. METHODS: Patients were eligible if cancer recurrence (non-small-cell lung (NSCL), breast, head and neck, ovarian, oesophageal, Hodgkin's or non-Hodgkin's lymphoma) was suspected clinically, and if conventional imaging was non-diagnostic. Clinicians were asked to indicate their management plan before and after (18)F-FDG PET-CT scanning. The primary outcome was change in planned management after (18)F-FDG PET-CT. RESULTS: Between April 2009 and June 2011, 101 patients (age, median 65 years; 55% female) were enroled from four cancer centres in Ontario, Canada. Distribution by primary tumour type was: NSCL (55%), breast (19%), ovarian (10%), oesophageal (6%), lymphoma (6%), and head and neck (4%). Of the 99 subjects who underwent (18)F-FDG PET-CT, planned management changed after (18)F-FDG PET-CT in 52 subjects (53%, 95% confidence interval (CI), 42-63%); a major change in plan from no treatment to treatment was observed in 38 subjects (38%, 95% CI, 29-49%), and was typically associated with (18)F-FDG PET-CT findings that were positive for recurrent cancer (37 subjects). After 3 months, the stated post-(18)F-FDG PET-CT management plan was actually completed in 88 subjects (89%, 95% CI, 81-94%). CONCLUSION: In patients with suspected cancer recurrence and conventional imaging that is non-diagnostic, (18)F-FDG PET-CT often provides new information that leads to important changes in patient management.
