Polar cardenolide monoglycosides from stems and twigs of Nerium oleander and their biological activities

Twelve polar cardenolide monoglycosides, 1, 2, 4?C13, and oleagenin (3) were isolated from the methanol extract of stems and twigs of Nerium oleander. Among these, oleagenin (3) and cardenolide monoglycosides named cardenolide B-1 (1) and cardenolide B-2 (2) were isolated from natural sources for the first time. The in vitro antiinflammatory activity of compounds 1?C13 was examined on the basis of inhibitory activity against the induction of the intercellular adhesion molecule-1 (ICAM-1). Compounds 4?C7 were active at an IC₅₀ value of less than 0.4 ??M. The cytotoxic activity of compounds 1?C13 was evaluated against three human cell lines: normal human fibroblast cells (WI-38), malignant tumor cells derived from WI-38 (VA-13), and human liver tumor cells (HepG2). Compounds 4, 6, and 7 were active toward these three cell lines at IC₅₀ values of less than 0.7 ??M, and compounds 5 and 8 were active toward the cell lines at IC₅₀ values of less than 1.5 ??M. The multidrug resistance (MDR) cancer-reversal activity of compounds 1?C13 was evaluated on the basis of the amount of calcein accumulated in MDR human ovarian cancer 2780AD cells in the presence of each compound. Compound 1 and 12 showed significant effects on calcein accumulation.     

Differences in numbers of nodules and lateral roots between soybean (Glycine max L. Merr.) cultivars,Kitamusume and Toyosuzu

Two cultivars of soybean (Glycine max L. Merr .), Kitamusume and Toyosuzu were grown with commercially-purchased granulated soil in a greenhouse. Kitamusume formed a larger number of nodules per g shoot dry weight and its nodules showed a smaller average diameter and average dry weight per nodule than Toyosuzu regardless of plant age or rhizobial strains (Bradyrhizobium japonicum (AI017, J5033, 646, J1B140), B. elkanii (USDA94), and Rhizobium fredii (MAFF210054)) inoculated at the rate of 10⁸-10⁹ cells per 3 L pot. These differences were observed in the nodules formed on both primary and lateral roots. With a lower inoculation dose of rhizobia (10² and 10⁵ cells per pot), Kitamusume formed a smaller number of larger nodules than Toyosuzu inoculated with 10⁸-10⁹ cells per pot. This result indicated that the number of nodules was the factor directly controlled by host, because the size of the nodules was not determined by the genetic background, but changed depending on the number of nodules formed. The number of the first order lateral roots of 21 d old Kitamusume was 1.49 times larger than that of Toyosuzu. The relationship between the number of nodules and the number of first order lateral roots of 14 cultivars showed a significant positive correlation. These results indicated that the formation of nodules and lateral roots may be similarly controlled by a certain factor in different cultivars.     

Enzymatic hydrolysis of diazoxon by rat tissue homogenates

The enzymatic hydrolysis of ³²P-labeled diazoxon was studied using tissue homogenates of rat and American cockroach. The order of the hydrolytic activities of rat tissues for diazoxon was as follows: liver > blood > lung > heart > kidney > brain. A liver enzyme hydrolyzing diazoxon to diethyl phosphoric acid and 2-isopropyl-4-methyl-6-hydroxypyrimidine was located in the microsomes. The activity of the microsomal enzyme was inhibited by EDTA, heavy and rare earth metal ions, and SH reagents. Ca²⁺ activated the enzyme and protected it from inactivation. Mitochondrial and soluble enzymes from liver and a serum enzyme also hydrolyzed diazoxon and they were also activated by Ca²⁺. The removal of calcium bound to the microsomal enzyme protein by dialysis against EDTA led to a partially irreversible change of the enzyme. The hydrolysis of diazoxon by the Ca²⁺-requiring microsomal and serum enzymes was more rapid than that of paraoxon. Hydrolysis of diazoxon did not occur in American cockroach homogenates. This difference in the capacity to hydrolyze diazoxon between mammals and insects is discussed in relation to the selective toxicity of diazinon.     

Genetic analysis of litter size in mice

We performed quantitative trait locus (QTL) mapping analysis for litter size (total number of pups born and/or number of pups born alive) in 255 backcross mice derived from C57BL/6J and RR/Sgn inbred mice. We identified one significant QTL on chromosome 7 and 4 suggestive QTLs on chromosomes 3, 5, 10 and 13. In addition, two suggestive QTLs were identified on chromosomes 1 and 4 for the number of stillbirth. These results suggested that both litter size and number of stillbirth were heritable traits, although they were controlled by distinct genes. The RR allele was associated with reduced litter size and increased stillbirth at all QTLs. Therefore, RR mothers were observed to have reduced prolificacy in this particular genetic cross.     

带单轴拖车拖拉机自动倒车行驶的研究

该研究中,应用最优控制理论设计了带单轴拖车拖拉机自动倒车行驶的控制方法。首先利用二次变分法设计了车辆自动行驶的轨道;其次,对车辆运动学方程进行了线性化处理;最后应用最优控制理论,设计了车辆沿行驶轨道自动行驶的一种时变线性二次型控制器,利用设计的行驶轨道和控制器进行了实车试验。试验表明,该控制方法能够实现带单轴拖车拖拉机自动倒车行驶控制。     

Toward sustainable harvest strategies for marine fisheries that include recreational fishing

Recreational fishing (RF) is a large yet undervalued component of fisheries globally. While progress has been made in monitoring, assessing, and managing the sector in isolation, integration of RF into the management of multi-sector fisheries has been limited, particularly relative to the commercial sector. This marginalises recreational fishers and reduces the likelihood of achieving the sector's objectives and, more broadly, achieving fisheries sustainability. We examined the nature and extent of RF inclusion in harvest strategies (HSs) for marine fisheries across 15 regions in 11 nations to define the gap in inclusion that has developed between sectors. We focused on high-income nations with a high level of RF governance and used a questionnaire to elicit expert knowledge on HSs due to the paucity of published documents. In total, 339 HSs were considered. We found that RF inclusion in HSs was more similar to the small-scale sector (i.e., artisanal, cultural, or subsistence) than the commercial sector, with explicit operational objectives, data collection, performance indicators, reference points, and management controls lacking in many regions. Where specified, RF objectives focused on sustainability, economic value and catch allocation rather than directly relating to the recreational fishing experience. Conflicts with other sectors included competition with the commercial sector for limited resources, highlighting the importance of equitable resource allocation policies alongside HSs. We propose that RF be explicitly incorporated into HSs to ensure fisheries are ecologically, economically, and socially sustainable, and we recommend that fisheries organisations urgently review HSs for marine fisheries with a recreational component to close the harvest strategy gap among sectors.     

<Emphasis Type="Italic">Tobacco mosaic virus</Emphasis> Is Transmissible from Tomato to Tomato by Pollinating Bumblebees

Tobacco mosaic virus (TMV) was detected by ELISA, electron microscopy and/or bioassay from bumblebee (Bumbus terrestris), pollen clumps, nest materials and bee-visited anthers of flowers from greenhouses in which tomatoes had been pollinated by bees and were severely infected with TMV. Experimental bee-mediated transmission of TMV in greenhouse tomatoes demonstrated that the bumblebees transported TMV from plant to plant and that they spread the virus in greenhouses. This is the first report describing TMV transmission by bumblebees. Received 11 August 1999/ Accepted in revised form 30 September 1999     

Effects of introgressions from <Emphasis Type="Italic">Festuca pratensis</Emphasis> on winter hardiness of <Emphasis Type="Italic">Lolium perenne</Emphasis>

Previous studies reported that some genotypes with introgressed Festuca chromosome segment(s) in Lolium genome showed enhanced winter hardiness compared to Lolium. The aim of this study was to search comprehensively for the Festuca pratensis chromosome regions affecting winter hardiness-related traits when introgressed into the Lolium perenne genome. Association between F. pratensis introgression and winter hardiness-related traits (fall and winter hardiness indexes, early-spring dry matter yield, and freezing tolerance) were screened in the diploid introgression populations (n = 203) that had some F. pratensis chromosome segments introgressed. Eighty-four intron markers corresponding to unique rice genes randomly distributed across the genome were used for genotyping. Winter hardiness of almost all plants in the introgression populations was lower than that of the F. pratensis and triploid hybrid parents, but the average was higher than that of L. perenne. A significant positive effect of F. pratensis introgression on early-spring dry matter yield was detected on chromosome 7. This quantitative trait locus (QTL) was confirmed by linkage analysis using a backcross population with F. pratensis introgression in the target region of chromosome 7. However, the contribution of the newly identified QTL was rather small (6.7–9.6%), suggesting that superior winter hardiness of F. pratensis compared to L. perenne is conferred by multiple small-effect QTLs. We also detected a previously unreported negative effect of Festuca introgression on winter hardiness. Newly obtained QTL information in this study would contribute to the design of Festuca/Lolium hybrid breeding.     

Genetic analysis of low survival rate of pups in RR/Sgn inbred mice

Newborn offspring of the inbred mouse RR/Sgn strain have a low survival rate prior to weaning. We hypothesized that this is a consequence of an inferior nurturing ability of RR/Sgn mothers and that RR/Sgn mothers have a tendency to lose their pups. We performed quantitative trait locus (QTL) mapping for inferior nurturing ability and tendency to lose pups in RR/Sgn mothers. The number of pups was adjusted to 6 per dam on the day of delivery, and the number of surviving pups and their total weight (litter weight) were scored at 12 days after birth. Nurturing ability was evaluated by litter weight, and tendency to lose pups was evaluated by scoring whether or not the mothers lost their pups. For litter weight, we identified one significant QTL on chromosome 4 and three suggestive QTLs on chromosomes 7, 9 and 17. The RR/Sgn allele was associated with lower litter weight at all loci. For the tendency to lose pups, we identified three suggestive QTLs on chromosomes 4, 9 and 16. The RR/Sgn allele was associated with an increased tendency to lose pups at all loci. These results supported our hypothesis that the low survival rate phenotype was attributable, at least in part, to a phenotype whereby mothers display inferior nurturing ability and a tendency to lose pups. Thus, it suggests that these two traits share genetic basis.     

The biological activities of cardenolide triglycosides from stems, twigs, and leaves of Nerium oleander

Sixteen cardenolide triglycosides (1?C16) were isolated from stems, twigs, and leaves of Nerium oleander. Among them, 3??-O-(4-O-gentiobiosyl-d-diginosyl)-7??,8-epoxy-14-hydroxy-5??,14??-card-20(22)-enolide, named cardenolide B-3 (16), was isolated from natural sources for the first time. The in vitro anti-inflammatory activities of compounds 1?C16 were examined on the basis of inhibitory activity against the induction of intercellular adhesion molecule-1 (ICAM-1). Compounds 1?C5 were active at an IC50 value of less than 7 ??M. The cytotoxic activity of isolated compounds was evaluated against three human cell lines: normal human fibroblast cells (W-38), malignant tumor cells induced from WI-38 (VA-13), and human liver tumor cells (HepG2). Compounds 1?C5 were active toward WI-38 cells; compounds 1, 3, and 5 were active toward VA-13 cells; and compounds 1?C5 were active toward HepG2 cells at IC₅₀ values of less than 10 ??M. The multidrug-resistant (MDR) cancer-reversal activity of compounds 1?C16 was evaluated on the basis of the amount of calcein accumulated in MDR human ovarian cancer 2780AD cells in the presence of each compound. Compounds 13 and 14 showed significant effects on calcein accumulation.