The effect of slag on paddy rice

To raise more rice in Japan we have placed much fertilizers in the fields, thus the soils often have been degraded by the leaching of essential elements including Fe to such a extent as rice roots are injured by the H₂S produced by the reduction of sulphates. It has been encouraged by law to place non-sulphate fertilizers and iron compounds in these fields.     

Effect of rice straw on the composition of volatile soil gas and micro flora in the tropical paddy field

The effect of rice straw on the composition of volatile soil gas and microflora in the tropical paddy field was studied with and without fertilizer application.

The volatile soil gas most abundantly found in plots with rice straw was methane followed by other gases, nitrogen, oxygen and carbon dioxide during the early stage of rice growth, while nitrogen predominated in later stages.

The loss of soil nitrogen through volatilization increased following phosphorus application as well as rice straw application as compared with that in the control plot. In the former case, the enhancement of decomposition of organic-N was assumed to be due to the increase in population of cellulose decomposer.

Rice straw application with or without N-fertilizer increased methane gas formation by 27 to 63 times as compared with the phosphorus plot and the peak of its formation was found 5 to 7 weeks after rice straw application. However methane formation in the control plot was very low and was found only 5 to 9 weeks after flooding.

Rice straw application usually increased the number of various groups of microorganisms along with contributing to the transformation of organic-N to N₂ gas. But the stimulating effect was chiefly observed in the population of Azotobacter.     

Effects of Polybrominated Diphenol Ethers from a Marine Sponge Phyllospongia dendyi on IL-8 Production in a PMA-stimulated Promyelocytic Leukemia Cell Line

The effects of five polybrominated diphenol ethers from a Marine Sponge, Phyllospongia dendyi, on the relative plating efficiencies in V79 cells and the cell proliferation and IL-8 production in PMA-stimulated HL-60 cells were examined. Three compounds, possessing two phenol units, were reported to inhibit the assembly of microtubule proteins and showed the inhibition of colony formation of V79 cells and increase in IL-8 production. Interestingly, a monomethoxy compound exhibited the stronger activity than the three active compounds in both bioassays. This compound did not inhibit the assembly of microtubule proteins. A dimethoxy compound was not active in either bioassays. In these experimental conditions, the biological activities were not high, but in future, these compounds will be expected to be made stronger by structural modifications.     

Inhibitory Effect of N,N-Didesmethylgrossularine-1 on Inflammatory Cytokine Production in Lipopolysaccharide-Stimulated RAW 264.7 Cells

N,N-Didesmethylgrossularine-1 (DDMG-1), a compound with a rare α-carboline structure, was isolated from an Indonesian ascidian Polycarpa aurata as responsible for the observed inhibitory activity against TNF-α production in lipopolysaccharide-stimulated murine macrophage-like RAW264.7 cells. DDMG-1 inhibited the mRNA level of mTNF-α, IκB-α degradation, and binding of NF-κB to the target DNA site in LPS-stimulated RAW 264.7 cells. Moreover, DDMG-1 had an inhibitory effect on the production of IL-8, which is produced in CD14⁺-THP-1 cells stimulated by LPS. DDMG-1 is thus a promising drug candidate lead compound for the treatment of chronic inflammatory diseases, such as rheumatoid arthritis.     

Linkage analysis of RFLP markers for clubroot resistance and pigmentation in Chinese cabbage (Brassica rapa ssp. pekinensis)

A restriction fragment length polymorphism (RFLP) – based linkage map of Chinese cabbage (Brassica rapa ssp. pekinensis) (2n=20) including two agronomic traits, clubroot resistance and orange-yellow pigmentation, was constructed using doubled haploid parents. The total linkage distance was 735 cM; 63 loci were distributed into ten linkage groups. Clubroot resistance of the parental line T136-8 to the current pathotype, race 2, was predominantly controlled by a single dominant gene that originated from European turnip. The locus for clubroot resistance by the dominant major gene (CRa) was mapped on linkage group 3, and RFLP loci HC352b and HC181 were located 3 cM and 12 cM from it, respectively. The locus HC352b was identified by a 4.4 Kb Eco R I fragment, which segregated for null allele. The absence of an allelic fragment in HC352b could be interpreted by deletion in the resistance source; homozygotes for CRa could be efficiently selected by detecting null types for the marker. Orange-yellow pigmentation expressed in head inner leaves and petals was governed by a single recessive gene. The locus (Oy) for the pigmentation was mapped on linkage group 1, being located 17–19 cM from three RFLP loci that were closely linked to each other. The linkage analysis for clubroot resistance and unique pigmentation revealed some informative RFLP markers. Identification of molecular markers for clubroot resistance and other agronomically important traits would provide useful information in breeding programs of Chinese cabbage. This revised version was published online in August 2006 with corrections to the Cover Date.     

A transdisciplinary research of coastal fisheries co-management: the case of the hairtail <Emphasis Type="Italic">Trichiurus japonicus</Emphasis> trolling line fishery around the Bungo Channel,Japan

Under the coastal fisheries co-management regime in Japan, local fishers play important roles in deciding on and implementing local management measures. Therefore, using the case study of a hairtail trolling line fishery, we conducted a transdisciplinary research with fishers, processors, government officers, etc. Taking social and biological factors into account, we defined management criteria and targets (resource, economic, human community, and local food culture) in collaboration with local fishers. We chartered local fishing vessels to determine parameters that were easily understood by local fishers. We established a local consultative committee comprising fishers, processors, and distributors, and developed a fish distribution strategy to nurture the local hairtail food culture. The integrated effects of various management scenarios were evaluated by the operating model. We found that co-ordinated management by both the trolling line fishery and purse seiners in the neighbouring prefecture was required to achieve targets. Two realistic scenarios are recommended: a conservative scenario that could achieve targets even with few strong year classes, and an adaptive scenario that protects strong year classes, but relies on a higher frequency of these. We shared these results with the local fishers and government officers, which led to actual improvements in management measures.     

Conservation of small hairtail <Emphasis Type="Italic">Trichiurus japonicas</Emphasis> by using hooks with large artificial bait: effect on the trolling line fishery

Overfishing has reduced the stock of hairtail Trichiurus japonicus around the Bungo Channel, Japan. To determine whether using larger bait in the trolling line fishery could avoid catching small/undersize hairtail, we developed and trialled a new large artificial bait (a soft plastic bait, 6 inches long). A traditional lure with natural bait (type-1), a new lure of the new artificial bait hook without natural bait (type-2), and a new lure with natural bait (type-3) were tested in fishing operations around the Bungo Channel. Compared with type-1, type-2 and type-3 caught fewer undersized and immature female individuals. The number of fish caught, yield, and composition of commercial size grades per recruitment were calculated from field data for each lure and compared. The catch sizes (number of fish per recruitment) were smaller for type-2 and type-3 than for type-1, but yield per recruitment was higher for type-3 than for type-1. Compared with type-1, type-2 and type-3 caught more large individuals, which are more valuable. The newly developed artificial bait conserves hairtail stocks by targeting larger fish, which is economically beneficial for the hairtail trolling line fishery.     

Age validation,growth and annual reproductive cycle of chub mackerel <Emphasis Type="Italic">Scomber japonicus</Emphasis> off the waters of northern Kyushu and in the East China Sea

The age and growth of chub mackerel Scomber japonicus collected from the East China Sea and the northern waters off Kyushu between June 2000 and June 2001 were determined by observing the otolith surface after dipping it in xylene. The translucent and opaque zones on the otolith surface were identified, and the number of translucent zones was counted. Monthly changes in the frequency of fish with translucent zones on the otolith margin, and in the marginal increments, indicated that the translucent zones were formed between April and June. The seasonal pattern of annulus formation on the otolith became clear by observing the otoliths of fish with known ages, and the otolith formation in wild fish was consistent with that of fish with known ages. The mean gonadosomatic index of male and female fish was high from March to May, and spawning females were observed from mid-March to mid-May. The estimated ages were 1–5 years for males and 1–6 years for females. The von Bertalanffy growth parameters did not significantly differ between male and female. The model was obtained as FL _t=406×{1−exp[−0.372×(t+1.68)]