Apple latent spherical virus (ALSV)-induced gene silencing in a medicinal plant, Lithospermum erythrorhizon.

Lithospermum erythrorhizon is a medicinal plant that produces shikonin, a red lipophilic naphthoquinone derivative that accumulates exclusively in roots. The biosynthetic steps required to complete the naphthalene ring of shikonin and its mechanism of secretion remain unclear. Multiple omics studies identified several candidate genes involved in shikonin production. The functions of these genes can be evaluated using virus-induced gene silencing (VIGS) systems, which have been shown advantageous in introducing iRNA genes into non-model plants. This study describes the development of a VIGS system using an apple latent spherical virus (ALSV) vector and a target gene, phytoene desaturase (LePDS1). Virus particles packaged in Nicotiana benthamiana were inoculated into L. erythrorhizon seedlings, yielding new leaves with albino phenotype but without disease symptoms. The levels of LePDS1 mRNAs were significantly lower in the albino plants than in mock control or escape plants. Virus-derived mRNA was detected in infected plants but not in escape and mock plants. Quantitative PCR and deep sequencing analysis indicated that transcription of another hypothetical PDS gene (LePDS2) also decreased in the defective leaves. Virus infection, however, had no effect on shikonin production. These results suggest that virus-based genetic transformation and the VIGS system silence target genes in soil-grown L. erythrorhizon.

Convenience of the computed tomography perfusion method for cerebral vasospasm detection after subarachnoid hemorrhage.

BACKGROUND: Vasospasm is a frequent complication in the early clinical course after SAH. Although various methods have been used to measure cerebral perfusion including PET, SPECT, xenon CT, and TCD, these require the patients to remain still for a long period. In addition, TCD is operator dependent. The current study aimed to clarify the convenience of CTP for the assessment of cerebral vasospasm caused by SAH. METHODS: Nineteen patients with SAH aged 44 to 85 years (mean, 64 years) were recruited with informed consent. All patients were treated with the prevailing therapy and underwent CTP on days 6 to 9, followed by DSA and 3D-CTA to detect cerebral vasospasm. In each patient, we measured the MTT, CBF, and CBV. The reliability of CTP data was verified by comparing the data from CTP and xenon CT between the controls, and the average was calculated. Six ROIs were located symmetrically in the frontal, temporal, and occipital lobes. RESULTS: An MTT value more than 20% greater than the average indicated the progression of cerebral vasospasm, and patients with vasospasm-related infarcts exhibited an MTT more than 47% greater than the mean value (odds ratio, 50). Patients with delayed cerebral infarcts had a significantly lower mean CBF and CBV and higher MTT than patients who did not develop CI. CONCLUSION: Significant correlations between MTT and CBF values and neurovascular findings were obtained. Computed tomography perfusion can be performed in a short time and on a regular basis, and it therefore has the potential to identify cerebral vasospasm because of SAH.