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Filoviruses, including Ebola virus (EBOV) and Marburg virus (MARV), cause severe hemorrhagic fever in humans and nonhuman primates with high mortality rates. There is no approved therapy against these deadly viruses. Antiviral drug development has been hampered by the requirement of a biosafety level (BSL)-4 facility to handle infectious EBOV and MARV because of their high pathogenicity to humans. In this study, we aimed to establish a surrogate animal model that can be used for anti-EBOV and -MARV drug screening under BSL-2 conditions by focusing on the replication-competent recombinant vesicular stomatitis virus (rVSV) pseudotyped with the envelope glycoprotein (GP) of EBOV (rVSV/EBOV) and MARV (rVSV/MARV), which has been investigated as vaccine candidates and thus widely used in BSL-2 laboratories. We first inoculated mice, rats, and hamsters intraperitoneally with rVSV/EBOV and found that only hamsters showed disease signs and succumbed within 4 days post-infection. Infection with rVSV/MARV also caused lethal infection in hamsters. Both rVSV/EBOV and rVSV/MARV were detected at high titers in multiple organs including the liver, spleen, kidney, and lungs of infected hamsters, indicating acute and systemic infection resulting in fatal outcomes. Therapeutic effects of passive immunization with an anti-EBOV neutralizing antibody were specifically observed in rVSV/EBOV-infected hamsters. Thus, this animal model is expected to be a useful tool to facilitate in vivo screening of anti-filovirus drugs targeting the GP molecule.

Although Japanese morning glory (Ipomoea nil (L.) Roth.) has been used intensively for genetic studies, DNA markers have not been developed in Ipomoea nil sufficient to cover all chromosomes. Therefore, we conducted microsatellite (simple sequence repeats, SSR) marker development in I. nil for future genetic studies. From 92,662 expressed sequence tag (EST) sequences, 514 unique microsatellite-containing ESTs were identified. Primer pairs were designed automatically in 326 SSRs. Of 150 SSRs examined, 75 showed polymorphisms among strains. A phenogram based on the SSR genotypes revealed the genetic relation among seven Japanese morning glories from five different regions of the world and an ivyleaf morning glory (I. hederacea Jacq.). The developed SSR markers might be applicable for genetic studies of morning glories and their relatives.

An agravitropic mutant of morning glory (Pharbitis nil.), weeping, has defect in shoot gravitropism. The previous results showed that weeping also showed defect in proper endodermis development and in shoot circumnutation, and such defect in circumnutation was also observed in similar endodermis-less Arabidopsis mutant, scarecrow (scr). In search of the mutated gene of weeping, cDNAs for SCR homolog from morning glory (PnSCR) were cloned from both wild type and weeping, respectively, and analyzed. An amino acid insertion was found in PnSCR from weeping. To investigate whether this insertion inactivates the PnSCR functions, complementation test was performed by introducing wild and weeping type PnSCR to the different Arabidopsis scr mutants respectively. As a result, endodermis-less and shoot agravitropic phenotypes were rescued by wild type introducing PnSCR, whereas introduction of weeping type PnSCR did not rescue them. Moreover, shoot circumnutation was also restored in scr mutant to which wild type PnSCR was transformed, but transformed weeping type PnSCR did not restore shoot circumnutation. These results strongly suggest that defects in gravitropism, proper endodermis development, and circumnutation observed in weeping are attributable to the loss of function of PnSCR. Possibility for usage of weeping morning glory as a new model plant in space biology is discussed., 資料番号: AA0048095069

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