Effect of catechins on mutagenesis of Salmonella typhimurium TA 102 elicited by tert-butyl hydroperoxide (t-BuOOH)

Green tea, one of the most popular beverages consumed in Asian countries, has been reported to possess anticarcinogenic and antimutagenic properties. The aim in this study is to test the radical scavenging effect of catechins and caffeine, which were major components of green tea, and if they really prevent oxygen radical-induced mutagenesis. We used TA102 strain of Salmonella typhimurium which is sensitive to hydroxyl radical in the Ames mutation assay. We found that caffeine did not show any effects on mutagenesis in this system, but catechin significantly reduced mutagenesis or genotoxicity caused by hydroxyl radical. This radical-scavenging action of catechins may indeed contribute to the anticarcinogenic activity of green tea as has been proposed.     

Quantitative structure-activity studies of substituted benzyl chrysanthemates: 7. Relationship between induction of repetitive discharges and effects on the action potential

The effects of substituted benzyl (1R)-trans-chrysanthemates and related compounds on the action potential of the crayfish giant axon were investigated using an intracellular microelectrode. The effects are broadly classified into three types: deceleration of the falling-phase of the action potential (type A), elevation of the depolarizing after-potential (type B), and the combination type (type C). The potency of the type A compounds to decelerate the rate of the falling-phase was determined in terms of the concentration required for reducing the rate to a specified degree. This potency was shown to correlate with the potency to induce repetitive discharges in the cockroach central nerve cord in terms of minimum effective concentration, which was determined previously. The potency of the types B and C compounds to elevate the after-potential was, however, not related directly with the cockroach nerve repetitive activity. The elevation of the after-potential is one of the critical factors but other effects such as a depolarization of the resting potential may be involved in determining the repetitive activity.     

New approaches to wood bonding A base-activated lignin adhesive system

Current knowledge of wood surface characteristics and surface modification are briefly reviewed and the postulated effects of chemical activation are summarized. It was found that aqueous sodium hydroxide can effectively activate wood surfaces to give strong dry autohesive bonds, but only low wet strength was obtained. However, excellent dry and wet wood bond strengths, equivalent to phenol-formaldehyde bonded samples, were obtained when methylolated lignin was used in combination with 3N sodium hydroxide activation. Several mechanisms of base activation are suggested, including enhanced wood surface contact and reactivity.     

Secondary chronic respiratory acidosis in a dog following the cervical cord compression by an intradural glioma

An intradural tumor in the upper cervical region was found in a dog with quadriparesis and chronic respiratory acidosis. Surgical removal of the tumor in the atlas and intraoperative radiotherapy were attempted. The tumor was histologically diagnosed as a neural glioma. A preoperative acid-base disturbance was dramatically improved after surgery. The clinical changes appeared in this case suggest that compression of the spinal cord at this region may cause paralysis of the respiratory muscles and secondarily result in chronic respiratory acidosis following the respiratory insufficiency.     

Distribution of photoperiod-insensitive allele Ppd-A1a and its effect on heading time in Japanese wheat cultivars

The Ppd-A1 genotype of 240 Japanese wheat cultivars and 40 foreign cultivars was determined using a PCR-based method. Among Japanese cultivars, only 12 cultivars, all of which were Hokkaido winter wheat, carried the Ppd-A1a allele, while this allele was not found in Hokkaido spring wheat cultivars or Tohoku-Kyushu cultivars. Cultivars with a photoperiod-insensitive allele headed 6.9–9.8 days earlier in Kanto and 2.5 days earlier in Hokkaido than photoperiod-sensitive cultivars. The lower effect of photoperiod-insensitive alleles observed in Hokkaido could be due to the longer day-length at the spike formation stage compared with that in Kanto. Pedigree analysis showed that ‘Purple Straw’ and ‘Tohoku 118’ were donors of Ppd-A1a and Ppd-D1a in Hokkaido wheat cultivars, respectively. Wheat cultivars recently developed in Hokkaido carry photoperiod-insensitive alleles at a high frequency. For efficient utilization of Ppd-1 alleles in the Hokkaido wheat-breeding program, the effect of Ppd-1 on growth pattern and grain yield should be investigated. Ppd-A1a may be useful as a unique gene source for fine tuning the heading time in the Tohoku-Kyushu region since the effect of Ppd-A1a on photoperiod insensitivity appears to differ from the effect of Ppd-B1a and Ppd-D1a.     

Development and evaluation of pyramiding lines carrying early or late heading QTLs in the indica rice cultivar ‘IR64’

The heading date is an important trait for determining regional and climatic adaptability in rice. To expand the adaptability of the indica rice cultivar ‘IR64’, we pyramided multiple early or late heading quantitative trait locus (QTLs) in the ‘IR64’ genetic background by crossing previously developed near-isogenic lines (NILs) with a single QTL for early or late heading. The effects of pyramiding QTLs were observed in three different climatic zones of the Philippines, Madagascar, and Japan. The early heading pyramiding lines (PYLs) headed 6.2 to 12.8 days earlier than ‘IR64’ while the late heading PYLs headed 18.8 to 27.1 days later than ‘IR64’. The PYLs tended to produce low grain yield compared to ‘IR64’. The low yield was not improved by combining SPIKE, which is a QTL that increases the number of spikelets per panicle. Conversely, ‘IR64-PYL(7+10)’ carrying Hd5 and Hd1 headed earlier, produced more tillers, and more panicles per m² than ‘IR64’, and mitigated the yield decrease in early heading. These results suggest that the effects of pyramided QTLs on heading date were consistent across various environments and PYLs could be used to enhance the adaptation of ‘IR64’ in other rice growing environments.     

Production of a desirable Brassica oleracea CMS line using an alloplasmic B. rapa CMS line carrying Diplotaxis erucoides cytoplasm as a bridge plant

In Brassica oleracea, production of F₁ hybrid seeds mainly makes use of the improved Ogura cytoplasmic male sterile (CMS) line. However, reliance on one particular line is a risk, and it would be advantageous to develop other CMS lines. In this study, we transferred Diplotaxis erucoides cytoplasm to B. oleracea cultivars using an alloplasmic B. rapaCMS line as a bridge plant to avoid incompatibility between donor and recipient plants. The new B. oleraceaCMS lines, which were derived by four generations of backcrossing, had small rudimentary anthers with no pollen grain and showed complete male sterility. There was no functional defect in other floral organs, and the ability to receive normal pollen did not appear to be impaired. Moreover, the B. oleraceaCMS lines carrying D. erucoides cytoplasm had larger leaf areas and a normal plastochron. As a consequence, the B. oleraceaCMS lines carrying D. erucoides cytoplasm have the potential to be valuable alternatives for use in commercial B. oleracea hybrid seed production.     

Characterization of near-isogenic lines carrying QTL for high spikelet number with the genetic background of an indica rice variety IR64 (Oryza sativa L.)

Total spikelet number per panicle (TSN) is one of the most important traits associated with rice yield potential. This trait was assessed in a set of 334 chromosomal segment introgression lines (ILs: BC₃-derived lines), developed from new plant type (NPT) varieties as donor parents and having the genetic background of an indica-type rice variety IR64. Among the 334 ILs, five lines which had different donor parents and showed significantly higher TSN than IR64 were used for genetic analysis. Quantitative trait locus (QTL) analysis was conducted using F₂ populations derived from crosses between IR64 and these ILs. As a result, a QTL for high TSN (one from each NPT donor variety) was detected on common region of the long arm of chromosome 4. The effect of the QTL was confirmed by an increase in TSN of five near-isogenic lines (NILs) developed in the present study. The variation in TSN was found among these NILs, attributing to the panicle architecture in the numbers of primary, secondary and tertiary branches. The NILs for TSN and the SSR markers linked to the TSN QTLs are expected to be useful materials for research and breeding to enhance the yield potential of rice varieties.     

Effects on flowering and seed yield of dominant alleles at maturity loci E2 and E3 in a Japanese cultivar,Enrei

‘Enrei’ is the second leading variety of soybean (Glycine max (L.) Merr.) in Japan. Its cultivation area is mainly restricted to the Hokuriku region. In order to expand the adaptability of ‘Enrei’, we developed two near-isogenic lines (NILs) of ‘Enrei’ for the dominant alleles controlling late flowering at the maturity loci, E2 and E3, by backcrossing with marker-assisted selection. The resultant NILs and the original variety were evaluated for flowering, maturity, seed productivity and other agronomic traits in five different locations. Expectedly, NILs with E2 or E3 alleles flowered later than the original variety in most locations. These NILs produced comparatively larger plants in all locations. Seed yields were improved by E2 and E3 in the southern location or in late-sowing conditions, whereas the NIL for E2 exhibited almost the same or lower productivity in the northern locations due to higher degrees of lodging. Seed quality-related traits, such as 100-seed weight and protein content, were not significantly different between the original variety and its NILs. These results suggest that the modification of genotypes at maturity loci provides new varieties that are adaptive to environments of different latitudes while retaining almost the same seed quality as that of the original.