Molecular and biological characterization of a bunyavirus infecting the brown planthopper (Nilaparvata lugens).

A negative-strand symbiotic RNA virus, tentatively named Nilaparvata lugens Bunyavirus (NLBV), was identified in the brown planthopper (BPH, Nilaparvata lugens). Phylogenetic analysis indicated that NLBV is a member of the genus Mobuvirus (family Phenuiviridae, order Bunyavirales). Analysis of virus-derived small interfering RNA suggested that antiviral immunity of BPH was successfully activated by NLBV infection. Tissue-specific investigation showed that NLBV was mainly accumulated in the fat-body of BPH adults. Moreover, NLBV was detected in eggs of viruliferous female BPHs, suggesting the possibility of vertical transmission of NLBV in BPH. Additionally, no significant differences were observed for the biological properties between NLBV-infected and NLBV-free BPHs. Finally, analysis of geographic distribution indicated that NLBV may be prevalent in Southeast Asia. This study provided a comprehensive characterization on the molecular and biological properties of a symbiotic virus in BPH, which will contribute to our understanding of the increasingly discovered RNA viruses in insects.

[Effects of electroacupuncture on long-term potentiation of synaptic transmission in spinal dorsal horn in rats with neuropathic pain].

OBJECTIVE: To observe the effect of electroacupuncture (EA) of "Huantiao" (GB 30) and "Weizhong" (BL 40) on the mechanical pain threshold and the long-term potentiation (LTP) of the spinal dorsal horn in rats with neuropathic pain. METHODS: Thirty SD rats were randomized into control (sham-operation), model and electroacupuncture (EA) groups, with 10 cases in each. The neuropathic pain model was established by ligature and transaction of the popliteal nerve and common peroneal nerve. EA (2 Hz, 1 mA) was applied to "Huantiao" (GB 30) and "Weizhong" (BL 40) on the affected side for 30 min, once daily for 7 days. The mechanical pain threshold of the paw was detected before and after modeling and EA. LTP of C-fiber stimulation (2 mA, 0.5 ms, 100 Hz, interval 10 s, 4 strains) evoked field potentials in spinal dorsal horn (L4/L5) was recorded in rats under anesthesia. RESULTS: Compared with control group, the pain threshold of model group reduced significantly from the 1st day on after ligature and transaction of the nerve (P<0.01), while 14 days after EA, it elevated evidently in comparison with model group (P<0.01), suggesting an increase of the mechanical pain threshold after EA. Comparison of the variance rates of C-fiber induced LTP of the field potential among the 3 groups showed that the variance rate of EA group was significantly lower than that of model group (P<0.01). Self-comparison of EA group showed that after EA, the variance rate of LTP reduced significantly (P<0.01). CONCLUSION: EA of "Huantiao" (GB 30) and "Weizhong" (BL 40) can significantly relieve neuropathic pain in rats with nerve injury, and inhibit C-fiber high-frequency-stimulation induced LTP due to central sensitization induced abnormality synaptic transmission.