Baculoviruses are a family of arthropod-specific viruses that produce two morphologically distinct types of virions (budded and occlusion-derived) in their lifecycle. Baculoviruses establish infection in the midgut of their host via the oral route: occlusion-derived virions have pivotal roles in these processes. This review summarizes the basic characteristics of baculoviruses, and discusses the composition and classification of baculovirus occlusion-derived virions. The latter focuses mainly on the evolution and role of multiple occlusion-derived virions in the lifecycle of baculoviruses. These achievements should aid understanding the evolution and infection mechanisms of baculoviruses.
Animals ; Baculoviridae ; genetics ; growth & development ; physiology ; Insecta ; virology ; Viral Proteins ; genetics ; metabolism ; Virion ; genetics ; growth & development ; physiology

To investigate the phenotypic characteristics of the strain of the rabies virus CTNCEC25, the strain of the China rabies virus CTN-1 adapted to primary chicken embryo cells (CECs), Vero cells, and mouse neuroblastoma N2a cells was inoculated with CTNCEC25 and parental CTN-1 strains to explore the cytopathic effect (CPE) and growth kinetics of CTNCEC25 on cultured cells. To determine the pathogenicity of CTNCEC25, suckling mice, adult mice, guinea pigs and rabbits were inoculated with CTNCEC25 via the intracerebral route and their survival monitored every day. Furthermore, the CTNCEC25 strain was passed serially in CECs for 20 passages and then 3 passages in the brains of suckling mice to determine phenotypic stability. CTNCEC25 achieved similar growth kinetics in Vero cells and N2a cells compared with parental CTN-1, but CTNCEC25 replicated more efficiently in CECs than the CTN-1 strain with a titer 72 h after infection reaching 10(7.5-7.6) FFU/mL, which was significantly higher than the 10(5.8) FFU/mL achieved by its parental strain, CTN-1. Moreover, CTNCEC25 induced apparent CPE in Vero cells, CECs and N2a cells. Analyses of intracerebral inoculation demonstrated that CTNCEC25 was attenuated profoundly in adult mice and was completely apathogenic to guinea pigs and rabbits, though it caused death in suckling mice. The CTNCEC25 strain proliferated steadily after serial passage in CECs and the brains of suckling mice, and remained avirulent in adult mice. These results suggest that CTNCEC25 is a highly attenuated and genetically stable strain of the rabies virus. CTNCEC25 replicated stably and efficiently in cultured cells and achieved high titers, so it could be a promising and safe vaccine strain for rabies prevention in China.
Animals ; Cell Line ; Cercopithecus aethiops ; China ; Guinea Pigs ; Humans ; Mice ; Rabbits ; Rabies ; virology ; Rabies virus ; genetics ; growth & development ; pathogenicity ; Serial Passage ; Viral Vaccines ; adverse effects ; genetics ; Virulence

Objective:To investigate the indication of pre-cut-endoscopic mucosal resection (pre-cut-EMR) on the treatment of colorectal laterally spreading tumors (LSTs).Methods:A retrospective study was performed on data of colorectal LSTs patients, who underwent pre-cut-EMR in Wuxi Second People’s Hospital and Zhongshan Hospital from January 2014 to June 2019. The relationships between the clinical characteristics of the lesions and the success rate and complications of pre-cut-EMR were analyzed.Results:Data of 132 colorectal LSTs cases were included in the study. Morphology of 29 (22.0%) LSTs were homogeneous granular type, 43 (32.6%) LSTs were mixed non-granular type, 58 (43.9%) LSTs were flat elevated type, and 2 (1.5%) LSTs were pseudo-depressed type. The diameter of lesions was 2.3±1.5 cm (ranged from 2.0 cm to 5.0 cm). Among the 132 LSTs, 36 (27.3%) tumors were located in rectum, 15 (11.4%) in sigmoid colon, 10 (7.6%) in descending colon, 17 (12.9%) in splenic flexure of colon, 21 (15.9%) in transverse colon, 24 (18.2%) in hepatic flexure of colon, 6 (4.5%) in ascending colon, and 3 (2.3%) in cecum. The histopathological diagnoses of the 132 LSTs included low grade intraepithelial neoplasia in 58 cases (43.9%), high grade intraepithelial neoplasia in 69 cases (52.3%), intramucosal carcinoma in 2 cases (1.5%), and canceration in 3 cases (2.3%). Pre-cut-EMR was achieved in all 132 patients, and the operation time was 25.3±13.6 min (ranged 20-65 min). The rate of en bloc resection and complete resection were 95.5% (126/132) and 100.0% (132/132), respectively. Two cases (1.5%) had intraoperative perforation, and were both located in the sigmoid colon with the diameter of 4.0 cm and 4.5 cm, respectively. Twelve cases (9.0%) had immediate bleeding during operation, and 2 cases (1.5%) had delayed bleeding after operation. Patients had been followed up for 6-24 months, the wound healed well after operation, and no local recurrence was found.Conclusion:Pre-cut-EMR is an effective and safe therapy for colorectal LSTs with diameter less than 4.0 cm.