Synthesis and insecticidal/acaricidal activity of novel 3‐(2,4,6‐trisubstituted phenyl)uracil derivatives

A series of novel 3‐(2,4,6‐trisubstituted phenyl)uracil derivatives has been synthesised and assayed for insecticidal/acaricidal activity. The assay indicated certain requirements for optimal insecticidal activity, which can be summarised as follows: (a) the substituents on the phenyl ring should possess hydrophobicity and electron‐withdrawing properties, and the sum of their volumes determines the level of activity; (b) the substituent at the 6‐position on the uracil ring should also possess electron‐withdrawing properties and hydrophobicity, together with the correct volume; (c) the 1‐position on the uracil ring should be unsubstituted for activity against Nephotettix cincticeps and Epilachna vigintioctopunctata, but substituents with length C3 to C4 may be optimal for activity against Tetranychus urticae; (d) certain substituents at the 5‐position of the uracil ring give activity against E vigintioctopunctata and T urticae, but not against N cincticeps; (e) a thiocarbonyl group at the 2‐position of the uracil ring is less effective than a carbonyl group. Of the compounds assayed, 3‐(2,6‐dichloro‐4‐trifluoromethylphenyl)‐6‐trifluoromethyluracil showed high activity against all the species assayed. © 2000 Society of Chemical Industry     

Confirmation of yessotoxin production by the dinoflagellate <Emphasis Type="Italic">Protoceratium reticulatum</Emphasis> in Mutsu Bay

ABSTRACT:   Yessotoxin (YTX) is a shellfish toxin and its contamination in bivalves has seriously damaged shellfish industries. The biogenetic origin of YTX was identified as the dinoflagellate Protoceratium reticulatum (Claparède et Lachmann) Bütschli collected in New Zealand and Yamada Bay, Iwate in Japan. Scallops cultured in Mutsu Bay, Japan, were frequently contaminated with YTX, however, occurrence of P. reticulatum in this bay and YTX production by the local strains have not been investigated. Eight strains of P. reticulatum , isolated from the bay, were cultured in the laboratory, and analyzed by fluorometric high-pressure liquid chromatography and liquid chromatography/mass spectrometry methods for YTX production and composition. All strains tested were confirmed to produce YTX, and none of them produced known YTX analogs. Toxin amount and composition differed from strain to strain. This result is also confirmation of one of the biogenetic origins of YTX in Mutsu Bay.     

In vitro assessment of the antiparasitic effect of caprylic acid against several fish parasites

The antiparasitic effect of caprylic acid against several fish parasites, i.e., the ciliate Cryptocaryon irritans (theronts), monogenean Benedenia seriolae (oncomiracidia and adults), copepod Pseudocaligus fugu (copepodids and adults) and myxosporean Kudoa shiomitsui (spores), was examined by in vitro trials.

Caprylic acid at a concentration of 1 mM had a parasiticidal effect against C. irritans theronts, B. seriolae oncomiracidia and K. shiomitsui spores and a contractile effect against B. seriolae adults, but had no clear effect against P. fugu copepodids and adults. These results suggest that caprylic acid may have an antiparasitic effect against various fish parasites, including parasites classified as monogenea, ciliates and myxosporea.     

Measurement of Indoor Sulfur Dioxide Emission from Coal–Biomass Briquettes

The coal–biomass briquette is an alternative fuel that replaces low-grade coal. It is expected that the use of coal–biomass briquettes will effectively reduce the indoor concentration of sulfur dioxide (SO₂) emitted during raw coal combustion. In this study, indoor concentrations of SO₂ emitted from combustion of either coal–biomass briquettes or low-grade coal in households in Nanchuan, which is in the rural area of Chongqing City, China, were measured. The acidic gases were collected using passive samplers, and the samplers were taken to the laboratory for extraction and measurement. The SO₂ concentrations resulting from the use of coal–biomass briquettes were clearly reduced compared with those resulting from the use of low-grade coal. The concentrations of SO₂ to which the inhabitants (housewives) of the houses were exposed were also measured, and were found to be less with coal–biomass briquettes. Although with coal–biomass briquettes exposure concentrations still exceeded the World Health Organization guideline for SO₂ (125 μ g m^?3), indoor air pollution and adverse effects on human health caused by SO₂ could be decreased by substituting coal–biomass briquettes for low-grade coal as a domestic fuel.     

Agent-based modeling of complex social–ecological feedback loops to assess multi-dimensional trade-offs in dryland ecosystem services

Context

Recent conceptual developments in ecosystem services research have revealed the need to elucidate the complex and unintended relationships between humans and the environment if we are to better understand and manage ecosystem services in practice.

Objectives

This study aimed to develop a model that spatially represents a complex human–environment (H–E) system consisting of heterogeneous social–ecological components and feedback mechanisms at multiple scales, in order to assess multi-dimensional (spatial, temporal, and social) trade-offs in ecosystem services.

Methods

We constructed an agent-based model and empirically calibrated it for a semi-arid region in Northeast China, and examined ecosystem service trade-offs derived from the Sloping Land Conversion Program (SLCP), which is based on payment for ecosystem services. This paper describes our model, named Inner Mongolia Land Use Dynamic Simulator (IM-LUDAS), using the overview, design concepts, and details + decision (ODD + D) protocol and demonstrates the capabilities of IM-LUDAS through simulations.

Results

IM-LUDAS represented typical characteristics of complex H–E systems, such as secondary and cross-scale feedback loops, time lags, and threshold change, revealing the following results: tree plantations expanded by the SLCP facilitated vegetation and soil restoration and household change toward off-farm livelihoods, as expected by the government; conversely, the program caused further land degradation outside the implementation plots; moreover, the livelihood changes were not large enough to compensate for income deterioration by policy-induced reduction in cropland.

Conclusions

IM-LUDAS proved itself to be an advanced empirical model that can recreate essential features of complex H–E systems and assess multi-dimensional trade-offs in ecosystem services.

     

Recovery of canopy trees and root collar sprout growth in response to changes in the condition of the parent tree after a fire in a cool-temperate forest

The relationship between the recovery of canopy trees after fire and root collar sprout dynamics was investigated during 1998–2000 in a secondary cool-temperate broad-leaved forest consisting of Quercus mongolica var. grosseserrata and Betula platyphylla var. japonica trees, in northern Hokkaido, Japan, which burned in April 1998. All of the Betula trees that were severely damaged, two-thirds of those slightly damaged, and half of those intact in 1998, died within three growing seasons after the fire. By contrast, half of the Quercus trees that were slightly damaged and half of those severely damaged recovered their foliage, and no slightly damaged or intact trees died during the three growing seasons after the fire. Many Betula trees developed several fruiting bodies of wood-destroying fungi on their stems, irrespective of damage severity. Fungi also infected some of the surviving Quercus, although the crowns tended to recover. Although many sprouting Betula were observed in 1998, the number of sprouts declined rapidly over the study period. Multiple regression analyses showed that the survival and growth of Betula sprouts were positively influenced by the number of sprouts in 1998, damage severity in 1998, and the degree of recover or decline during the study period, and were negatively influenced by parent tree size. On the other hand, a few sprouts of Quercus remained alive. Quercus remained dominant and the dominance of Betula was rapidly reduced after the fire. However, many Betula sprouts remained alive. Stand structure will change drastically for the time being.     

Nitrification Inhibitors from the root tissues of Brachiaria humidicola, a tropical grass

Nitrification inhibitory activity was found in root tissue extracts of Brachiaria humidicola, a tropical pasture grass. Two active inhibitory compounds were isolated by activity-guided fractionation, using recombinant Nitrosomonas europaea containing luxAB genes derived from the bioluminescent marine gram-negative bacterium Vibrio harveyi. The compounds were identified as methyl-p-coumarate and methyl ferulate, respectively. Their nitrification inhibitory properties were confirmed in chemically synthesized preparations of each. The IC50 values of chemically synthesized preparations were 19.5 and 4.4 microM, respectively. The ethyl, propyl, and butyl esters of p-coumaric and ferulic acids inhibited nitrification, whereas the free acid forms did not show inhibitory activity.     

Comparative assessment of Th1 and Th2 cytokines of swamp type buffalo and other bubaline breeds by molecular cloning, sequencing and phylogenetics

Comparative assessment of Th1 and Th2 cytokines of three bubaline breeds namely swamp buffalo, its crossbreed with riverine buffalo (CB), and the improved breed of Bulgarian Murrah buffalo (BMB), was done by molecular cloning, sequencing and phylogenetic analysis. The Th1 cytokines analyzed included IL-2, IL-12p35, IL-12p40, and IFN-gamma while Th2 cytokines included IL-4 and IL-10. Both groups showed strict conservation in the putative secondary structures and amino acid residues within the tribe Bovini, which indicated functional cross-reactivity. Nucleotide sequence homology ranged from 98.6 to 100.0% and was lowest for IL-12p35. With regard to amino acid sequence, the lowest homology was observed in IL-4 with 97.8%. This substitution was mainly due to differences in mRNA splicing. The phylogenetic relationship of the buffalo breeds was analyzed and showed them as a cluster comprised mainly of species belonging to the order Artiodactyla, including cattle and pigs. A deeper knowledge of these cytokine structures will favor understanding of water buffalo immunology and how much it differs from its closest subspecies and other animals.