Phytochrome-Mediated Photoorientation of Chloroplasts in Protonemal Cells of the Fern Adiantum Can be Induced by Brief Irradiation with Red Light

Measuring the ratio of the number of photooriented chloroplaststo the total number of chloroplasts, we found that photoorientationof chloroplasts in protonemata of the fern Adiantum capillus-veneriscould be induced by brief irradiation with polarized red light.After irradiation with red light (R) of 3 or 10 min, orientationalmovement was detected as early as 10 min after the irradiation;it continued during the subsequent dark period for 30–60min, after which chloroplasts gradually dispersed again. WhenR-treated protonemata were irradiated briefly with a second10-min pulse of R, 60 min after the onset of the first irradiation,the orientational response of chloroplasts was again observed.Typical red/far-red photoreversibility was apparent in the response,indicating the involvement of phytochrome. By contrast, irradiationwith polarized blue light for 10 min was ineffective, whileirradiation with blue light (B) at the same fluence for a longerperiod of time clearly induced the photoorientation of chloroplasts.It is likely that longterm irradiation is necessary for theresponse mediated by a blue-light receptor. When protonemata were irradiated with far-red light (FR) immediatelyafter R or after a subsequent dark period of 10 min, the magnitudeof the orientational response was smaller and chloroplasts dispersedmore quickly than those exposed to R alone. When FR was appliedat 50 min, when the response to R had reached the maximum level,chloroplasts again dispersed rapidly to their dark positions.These results indicate that P_FR not only induces the photoorientationmovement of chloroplasts but also fixes the chloroplasts atthe sites to which they have moved as a result of photoorientation. (Received June 2, 1993; Accepted January 11, 1994)     

Prevention of PERV infections in pig to human xenotransplantation by the RNA interference silences gene

The possibility of preventing the transmission of porcine endogenous retrovirus (PERV) to human cells using short interfering RNAs (siRNA) was investigated. The siRNA for the p30 of PERV gag region was cloned into pSUPER, the polymerase-III H1-RNA gene promoter. A green fluorescence protein (GFP) was also cloned into pSUPER to establish pSXGH. Pig endothelial cells (PEC) were transduced with the LacZ gene by pseudotype infection, and infected with PERV subtype B, resulting in the formation of PEC(LacZ)/PB. The PEC(LacZ)/PB was next transfected with pSXGH-siRNA. The expression of siRNA was provisionally checked by determining the level of expression of GFP. Culture supernatants of infected cells were then inoculated into HEK293 cells. The siRNA clearly destroyed the PERV infectivity of PEC(LacZ)/PB in both transient cell lines and stable clones. Moreover, the decreased levels of mRNA and gag protein were evidenced in the stable clones by real-time PCR and Western blotting, respectively. The final goal of our study was to establish a transgenic pig expressing the siRNA for PERV. The results suggest that siRNA represents a novel approach for controlling PERV infections in clinical xenotransplantation.     

Who will desire upper airway stimulation as a treatment of obstructive sleep apnea in the Japanese patient population?

Sleep and Biological Rhythms -     

Specificity of Enzyme System Producing C6-Aldehyde in Tea Chloroplasts

The substrate specificity of enzyme system producing C₆-aldehyde in Thea chloroplasts was clarified with an entire series of synthesized positional isomers, in which the position of cis-1, cis-4-pentadiene system varies from C-3 to C-13 in C₁₈ fatty acid and geometrical isomers of linoleic acid. The structural requirement for the substrate of enzyme system producing C₆-aldehyde is the presence of cis-1, cis-4-pentadiene system between ω-6 and ω-10.     

Formation of Threonine Aldolase by Bacteria and Yeasts

Threonine aldolase was found to be formed in various strains of bacteria and yeasts when they were grown in media containing l-threonine as a sole source of carbon. As the other sources of carbon, d, l-allothreonine, l-serine and glycine were effective but glucose and sucrose were inert for the formation of the enzyme.

The maximal formation of the enzyme was observed in the initial of stationary phase of growth and, thereafter, the enzyme disappeared with the consumption of l-threonine. It seems that the enzyme is adaptive in nature and that it is responsible for the growth in threonine as the carbon source.     

Adenosine A2A receptor deficiency attenuates the somnogenic effect of prostaglandin D2

Sleep and Biological Rhythms -     

Sex Allocation by a Parasitoid Wasp (Hymenoptera: Ichneumonidae) to Different Host Species: A Question for the Mechanism of Host Size Estimation

Sex allocation by the polyphagous solitary pupal parasitoid wasp Pimpla luctuosa Smith to a small host species, Galleria mellonella (L.), and a large host species, Mamestra brassicae L., was investigated to test whether female wasps responded to hosts of different sizes across different host species. In the experiments, both host species were presented to each test female wasp. Primary and secondary sex ratio experiments revealed that female wasps laid more female eggs in larger pupae of each host species, indicating that female wasps recognized size differences within host species. The wasp sex ratio (male ratio) from M. brassicae, however, was much higher than that expected on the basis of the sex ratio curve from different-sized G. mellonella. Larger hosts of each host species yielded larger wasps, indicating that the host size estimation by female wasps across different host species was incomplete or was not simple. These results suggested that P. luctuosa evaluated host size not only by physical measures such as dimension but also by other unknown measures. A possible explanation for the adaptiveness of different sex ratio responses by Pimpla luctuosa to different host species was discussed.     

稻瘟病抗病基因Pi15的精细定位

稻瘟病抗病基因Pi15曾被作者鉴定为与已知抗病基因Pii具有连锁关系,但是,Pii基因究竟位于染色体6还是9上存在争议。为了确定Pi15基因的染色体位置,利用分子标记在由15个抗病个体和141个感病个体组成的F_2群体中,通过混合群体分离法(BSA)与隐性群体分析法(RCA)相结合的手段,对目标基因进行了连锁分析。首先,从染色体6和9分别选择10个微卫星标记进行了分析,结果表明,只有位于染色体9的RM316与目标基因连锁,重组率为(19.1±3.7)％。为了进一步确定这种连锁关系,从染色体9选择了4个序列标定位点(STS)标记进行分析,结果表明,只有G103与目标基因连锁,重组率为(5.7±2.1)％。为了获得与目标基因更加紧密连锁的分子标记,对目标基囚进行了RAPD分析。在筛选、分析了1000个随机引物之后,从中获得了3个目标基因紧密连锁的分子标记BAPi15_(486)、BAPi15_(782)、BAPi15_(844)。它们与目标基因的重组率分别为0.35％、0.35％和1.1％。这些紧密连锁的分子标记可作为分子标记辅助基因聚合和克隆的出发点。