Quantitative structure-activity studies of benzoylphenylurea larvicides: II. Effect of benzyloxy substituents at aniline moiety against Chilo suppressalis Walker

The larvicidal activity of a series of N-2,6-difluorobenzoyl-N′-[4-(substituted benzyloxy)-phenyl]-ureas against nondiapause larvae of the rice stem borer, Chilo suppressalis Walker, was measured by a topical application method under conditions in which oxidative metabolism was inhibited by piperonyl butoxide. The effects of the substituted-benzyloxy moiety on variations in the activity were analyzed quantitatively using physicochemical substituent parameters and regression analysis. Results were compared with those found previously for N-2,6-difluorobenzoyl-N′-(4-substituted phenyl)-ureas, indicating that the electron-withdrawing property of the anilide substituents participates in determining the activity through the inductive effect. The hydrophobicity of the total anilide substituents favors activity, whereas the steric dimension in terms of the width lowers it. Although inhibition of new cuticle formation on cultured integument of diapausing larva could not be determined accurately for most of the compounds because of their limited solubility in the assay medium, inhibitory activity seemed related to larvicidal activity, as was the case for previously investigated simpler congeners.     

Water Stress and Potassium Fertilization in Field Grown Maize (Zea mays L.): Effects on Leaf Water Relations and Leaf Rolling

Three cultivars of maize ( Zea mays L.) were grown in the experimental field at Hiroshima University, Japan under two levels of K fertilization with a non-irrigated water stress treatment and an irrigated control during June to August 1990. Leaf water potential, osmotic potential and stomatal conductance were measured 21 d after withholding water. Diurnal changes in degree of leaf rolling were measured on the 22nd day after withholding water. Leaf water potential and osmotic potential at full turgor were lower in the non-irrigated plants than irrigated and they were lower in the high K plants than the low K plants. Lowering of osmotic potential (osmotic adjustment) helped to maintain turgor under low water potential conditions. Turgor potential was increased by the higher K fertilization. Higher turgor potential may contribute to the higher stomatal conductance observed in non-irrigated high K plants. The degree of leaf rolling increased towards noon, and it was lower in high K plants than in low K plants. High K plants recovered from leaf rolling faster than the low K plants during the afternoon. High K. plants could maintain higher turgor potential throughout the day than the low K plants. Degree of leaf rolling was the lowest in the cultivar K-8388 which maintained the highest turgor potential via osmotic adjustment and it recovered from leaf rolling faster than the other two cultivars. Higher levels of K fertilization may be beneficial for maize plants to tolerate to water stress conditions.     

Quantitative structure—activity relationships of light-dependent herbicidal 4-pyridone-3-carboxanilides I. Effect of benzene ring substituents at the anilide moiety

A number of substituted 4-pyridone-3-carboxanilide derivatives show various degrees of light-dependent herbicidal activity. The effects of substituents at the anilide moiety on the activity against Echinochloa oryzicola were analysed quantitatively with physicochemical substituent parameters. The activity was shown to vary parabolically with total hydrophobicity (Σπ) of the anilide ring substituents as well as with the steric parameter (E_s) of the ortho-substituents. The E_s parameter for only the bulkier ortho-substituent, with the more negative value, but not for the two, was significant. The effect of substituents at the 1-position was expressible by indicator variables assigned to each 1-substituted series, the physicochemical rationalization being left for future analyses.     

Quantitative structure-activity relationships of light-dependent herbicidal 4-pyridone-3-carboxanilides III. 3-D (comparative molecular field) analysis including light-dependent diphenyl ether herbicides

Using a set of representative members selected from 4-pyridone-3-carboxanilides and ortho-chlorinated diphenyl ethers exhibiting light-dependent herbicidal activity, we examined the three-dimensional structure-activity relationships quantitatively. The most stable conformation of each compound, regarded as the ‘active conformation’, was determined by either semi-empirical or ab initio molecular orbital calculations. With a hypothesis defining a common substructural skeleton between the two different compound series. each molecule was superimposed. We first analysed the structure-activity relationship using an index for the substructure shape similarity according to the superimposed conformations. After finding the relevance of the hypothesis, we examined the three-dimensional structure-activity relationship using the comparative molecular field analysis procedure. The results suggested that the two different series of compounds have a common region of the receptor site. The variations in the light-dependent herbicidal potency were governed by hydrophobicty and three-dimensional steric and electronic field parameters of molecules participating in the transport process and the interaction with the receptor site. The result was consistent with that derived from our previous quantitative analysis with the use of free-energy-related substituent parameters and the traditional regression procedure for a large number of pyridone-carboxanilides.     

Metabolite profiling reveals the involvement of aberrant metabolic changes in Gentiana triflora seed showing poor germination

Gentians are alpine plants and two endemic species, Gentiana triflora and G. scabra, are cultivated as ornamentals in Japan. Because most of the Japanese cultivars are F₁ hybrids, seed germination rate is an important factor for maintaining these cultivars. However, germination rates frequently differ among cultivars. Poor germination is a severe problem for gentian production, although there is almost no difference in their germination period and growth rate. In this study, we compared seed germination rates among three cultivars of G. triflora. A high rate of seed germination was observed in ‘Majel’ (MJ) and ‘Iwate’ (IW), but a low rate was recorded in ‘Iwate-Yumeminori’ (YM). We conducted a targeted metabolome analysis using these cultivars to elucidate the potential cause of inhibited seed germination. Multivariate analysis revealed that the aberrant accumulation of specific amino acids and a decrease in energy metabolites were observed in YM seed. Furthermore, protein concentrations and proteolytic activities in YM seed were lower than in MJ seed. These results imply that energy depletion was the main reason for the decreased rate of germination and that this depletion inhibited processes involved in seed germination, including de novo synthesis of the proteins necessary for germination.     

Quantitative structure-activity study of herbicidal N-aryl-3,4,5,6-tetrahydrophthalimides and related cyclic imides

The quantitative relationship between structure and inhibitory activity against the root growth of sawa millet of 30 N-aryl-3,4,5,6-tetrahydrophthalimides and 88 related N-aryl cyclic imide compounds (3-aryl-1,5-tetramethylenehydantoins, 4-aryl-1,2-tetramethylenetriazolidine-3,5-diones, and their thiocarbonyl analogs) was analyzed by means of physicochemical parameters of the aryl substituents and regression analysis. The results showed that, in each series of these classes of compounds, the position-specific steric effects of aromatic substituents, as represented by Verloop's STERIMOL values, are highly important in determining the inhibitory potency of the compound.     

Effects of a rice diet and phytase addition on growth performance,tissue weights,phosphorus and nitrogen retention,and on liver threonine dehydrogenase,malic enzyme and fatty acid synthase activities in broiler chicks

This experiment was conducted to clarify the nutritional functions of rice and phytase addition for broiler chicks. Thirty‐six 7‐day‐old male chicks (ROSS 308 strain) were assigned to one of the four treatment groups: corn‐ or rice‐based diet groups and each diet with added phytase (2000 phytase units/kg diet) groups (corn + P or rice + P groups). The non‐phytate phosphorus (npP) content in the diets with added phytase was approximately half of the requirement. Body weight gain and feed intake in the rice group was significantly higher than those in the corn group. Breast and thigh muscle weights and nitrogen retention in the rice group were significantly higher than that in the corn group. Although the efficiency of phosphorus retention (%) in the corn + P group was significantly higher than that in the corn group, no significant difference was observed between the rice and rice + P groups. Liver threonine dehydrogenase activity in the corn group was significantly higher than in the other three groups. These results indicate that rice is superior to corn as a starter diet in broiler chicks, and that phytase action in the rice‐based diet was less than that in the corn‐based diet.     

Development of an on-site plum pox virus detection kit based on immunochromatography

Sharka disease, caused by plum pox virus (PPV), is the most serious viral disease of stone fruit trees. Among the eight known strains of the virus, PPV-D is the most important due to its recent global spread. Although enzyme-linked immunosorbent assay (ELISA) is the most common approach for diagnosing sharka, it involves time-consuming steps and requires expensive equipment and trained technicians. In this study, an on-site PPV detection kit based on immunochromatography was developed using polyclonal antibodies against the coat protein (CP) of a PPV-D isolate. The immunochromatographic (IC) assay kit was as sensitive as a commercial ELISA system for detecting Japanese PPV-D isolates. Moreover, it was easy to use (a one-step procedure), and results could be obtained on-site within 15 min without special laboratory equipment. The IC assay kit detected the virus from every aerial part of symptomatic Japanese apricot trees. In a detailed study of viral localization in leaves, the most suitable plant parts for use in the IC assay were symptomatic mesophyll tissues and the region from the petiole to the main vein. A positive reaction was also observed using the CP of other major (PPV-M and PPV-Rec) and minor (PPV-EA, PPV-W, and PPV-T) strains.     

Morphological features and dietary functional components in fruit bodies of two strains of <Emphasis Type="Italic">Pholiota adiposa</Emphasis> grown on artificial beds

 The morphological features and dietary functional components of two strains (FPF-13 and Oninome-B) of Pholiota adiposa (numerisugitake mushroom) grown on artificial bed blocks were examined. The components examined were chitin, mannitol, trehalose, guanosine 5′-monophosphate, ergosterol, and β-glucan. There was a significant difference in the external shape of the two strains. However, the differences in the contents of functional components between the two strains, as well as between the pilei and stipes of the strains, were small. In both strains the trehalose content was much higher than the mannitol content, in contrast to those of Lentinula edodes. From a commercial point of view, Oninome-B has a clear advantage over other strains of P. adiposa owing to its less removable scale. Received: May 15, 2002 / Accepted: June 10, 2002 Acknowledgment The authors thank Dr. F. Eguchi (Takasaki University of Health and Welfare) for his technical advice on the β-glucan analysis. Part of this report was presented at the 51st Annual Meeting of the Japan Wood Research Society, Tokyo, April 2001 Correspondence to:K. Shimizu