Synthesis and structure-activity relationships of 1-phenyl-1H-1,2,3-triazoles as selective insect GABA receptor antagonists

To study the interaction of phenylheterocycles with gamma-aminobutyric acid (GABA) receptors, 4- or 5-alkyl(or phenyl)-1-phenyl-1H-1,2,3-triazoles were synthesized and examined for their ability to inhibit the specific binding of [3H]-4'-ethynyl-4-n-propylbicycloorthobenzoate (EBOB), a noncompetitive antagonist, to the housefly and rat GABA receptors, as well as to the beta3 subunit homo-oligomer of the human GABA receptor investigated as a model receptor. 4-Substituted 1-phenyl-1H-1,2,3-triazoles were found to be more potent competitive inhibitors than the 5-substituted regioisomers in the case of all receptors. The 4-tert-butyl or 4-n-propyl analogue of 1-(2,6-dichloro-4-trifluoromethylphenyl)-1H-1,2,3-triazole exhibited the highest level of inhibition of [3H]EBOB binding to all receptors. Most of the synthesized analogues were more active in terms of the inhibition of EBOB binding to the housefly and human beta3 GABA receptors than to the rat receptor. The 4-cyclohexyl analogue showed the highest (185-fold) housefly versus rat receptor selectivity. A three-dimensional quantitative structure-activity relationship (3D-QSAR) analysis demonstrated that both the 4-trifluoromethyl-2,6-dichloro substitution on the phenyl ring and a small, bulky, hydrophobic substituent at the 4-position of the triazole ring played significant roles in conferring high potency in cases involving the housefly and human beta3 receptors. The human beta3 receptor resembled the housefly receptor in terms of their recognition of phenyltriazoles, whereas 3D-QSAR analysis revealed a slight difference between the two receptors in terms of their mechanisms of recognition of the para-substituent on the phenyl moiety. Some of the triazoles synthesized here exhibited insecticidal activity, which was correlated with their ability to inhibit [3H]EBOB binding to the housefly receptor. Thus, 1-phenyl-1H-1,2,3-triazoles with the appropriate substituents exert insecticidal activity by selectively acting at the site for noncompetitive antagonism of insect GABA receptors.     

Histopathological changes of testes and eyes by neutron irradiation with boron compounds in mice

This study was performed to investigate the biological effects of boron neutron capture therapy (BNCT) on the testes and eyes in mice using HANARO Nuclear Reactor, Korea Atomic Energy Research Institute. BNCT relies on the high capacity of ¹⁰B in capturing thermal neutrons. Sodium borocaptate (BSH, 75 ppm, iv) and boronophenylalanine (BPA, 750 ppm, ip) have been used as the boron delivery agents. Mice were irradiated with neutron (flux: 1.036739E +09, Fluence 9.600200E+12) by lying flat pose for 30 (10 Gy) or 100 min (33 Gy) with or without boron carrier treatment. In 45 days of irradiation, histopathological changes of the testes and eyes were examined. Thirty-three Gy neutron irradiation for 100 min induced testicular atrophy in which some of seminiferous tubules showed complete depletion of spermatogenic germ cells. Lens epithelial cells and lens fiber were swollen and showed granular changes in an exposure time dependent manner. However, boron carrier treatment had no significant effect on the lesions. These results suggest that the examination of histopathological changes of lens and testis can be used as "biological dosimeters" for gauging radiation responses and the HANARO Nuclear Reactor has sufficient capacities for the BNCT.     

Estimation of rice protein content before harvest using ground-based hyperspectral imaging and region of interest analysis

Protein content, which represents rice taste quality, must be estimated in order to create a harvesting plan as well as next year’s basal dressing fertilizer application plan. Ground-based hyperspectral imaging with high resolution (1 × 1 mm per pixel) was used for estimating the protein content of brown rice before harvest. This paper compares the estimation accuracy of rice protein content estimation models generated from the mean reflectances of five regions of interest (ROIs): the overall target area, dark area (less illuminated parts of the rice plants), canopy area (leaves, yellow leaves, and ears), leaf area, and ear and yellow leaf area. The size of the target sampling area was 0.85 × 0.85 m. An R + G + B histogram and a GNDVI–NDVI image were used to separate the target area into the individual ROIs. The values of the coefficient of determination R ² and the root mean square error of prediction (RMSE) were similar for each model: R ² ranged from 0.83 to 0.86 and RMSE ranged from 0.27 to 0.30% for all models except for the dark area model, where R ² = 0.76 and RMSE = 0.35%. There were no significant differences in the magnitude of the estimation error among all models. This result indicates that it is not necessary to obtain an image with a ground resolution that is greater than 0.85 × 0.85 m per pixel to estimate rice protein content before harvest. This result should provide useful information when deciding the altitude of platforms for imaging rice fields.     

Endosulfan Plant Uptake Suppression Effect on Char Amendment in Oriental Radish

Persistent organic pollutants (POPs) immobilization in farm land is an important issue to solve the residue in crop, and char has been considered for the remediation. In here, three commercially available chars like powdered oak char (POC), granulated oak char (GOC), and rice husk char (RHC) including powdered activated carbon (PAC) were investigated for their potential to adsorb and immobilize endosulfan in the soil. The maximum adsorption capacities (mg g^?1) of the applied chars as POC, GOC, and RHC were 714.8, 322.6, and 181.8, respectively, and the capacity of POC was similar with PAC (713.8). In addition, the pore volume (0.138 cm³ g^?1) and the surface area (270.3 m² g^?1) of POC were over 3-fold higher than GOC and RHC. The bioconcentration factor (BCF) reducing effect of α-, β-endosulfan, and endosulfan sulfate in oriental radish (Raphanus sativus var. sativus) was investigated by amendment of three commercially available chars to the contaminated soils. The BCF of total endosulfan was 0.025 in the radish root. POC treatments effectively suppressed the endosulfan uptake (BCF 0.002). However, GOC and RHC showed little BCF reducing effect of endosulfan in radish.     

Plumbagin as a new natural herbicide candidate for Sicyon angulatus control agent with the target 8-amino-7-oxononanoate synthase

A natural compound plumbagin (5-hydroxy-2-methyl-1,4-naphthoquinone) was isolated from the leaves of Plumbago auriculata and found to inhibit the enzyme, 8-amino-7-oxononanoate synthase (AONS, also known as 7-keto-8-aminopelargonate synthase, KAPAS) an IC₅₀ of 2.1 μM in vitro. Biotin supplement significantly rescued the plant injury caused by the plumbagin treatment, and this result confirmed the target site, AONS. Foliar application of 1000 ∼ 2000 μg/mL plumbagin in a greenhouse condition showed lethal activity against eight species of weeds, containing three grass species of Sorghum bicolor, Echinochloa crus-galli, Digitaria sanguinalis and five broad leaf species of Solanum nigrum, Aeschynomene indica, Abutilon avicennae, Xanthium strumarium, Calystegia japonica. Field trial of foliar application with plumbagin 2000 μg/mL have successfully controlled 10 ∼ 15 leaf-stages and 2 ∼ 3 m vine lengths of Sicyos angulatus at the natural habitats around riparian zone in the Nam-Han River in Korea. Visual symptom of desiccation might be induced by the physiological cellular leakage which was significantly dose dependent on the plumbagin treatment regardless of light.     

Effects of cooldown methods and durations on equine physiological traits following high-intensity exercise

This study was initiated to investigate the physiologic effects of cooldown methods and durations on recovery following high-intensity exercise (3000 m, 10 m/s) of 25 Jeju crossbred horses. Heart rate (HR) was measured and blood samples were collected for glucose, blood lactate concentration, packed cell volume (PCV), total protein (TP), and hemoglobin (Hb) analysis. The cooldown methods employed involved walk rest (WR) or trot rest (TR), and the durations compared were 15, 30, and 60 min. A passive rest group (PR) was used as a control. According to the analysis, HR decreased after a 15 min rest in all groups, showing a faster recovery in the active rest groups, WR and TR, than in the PR group after 30 min (P < 0.05). In the case of glucose, the decrease was faster in the WR15 group then the WR30 group suggesting that active rest is more effective in controlling this parameter (P < 0.05). As for lactate, TR15 showed a 75% decrease which was a significantly positive effect. There were no differences in PCV between the groups. Horses in the PR group showed faster recovery for TP and Hb than those in the active rest groups (P < 0.05), while lactate removal was faster in active rest groups than in the PR group, suggesting that the cooldown process plays an important role in recovery. This study showed that the cooldown method and duration employed after high-intensity exercise of horses makes a difference with regard to their physiologic status. Also, 15 min rest after exercise appears to be the most significant period in terms of duration. In conclusion, active rest was necessary for rapid recovery and a 15 to 30 min cooldown walk or trot was beneficial to the horses in which physical fatigue had accumulated. In particular, the active exercise method of trotting was found to be more effective than walking to remove lactate. In addition, the cooldown duration is expected to be more effective when adjusted according to the individual training state of the horse.     

Immunolocalization of anion exchanger 1 (Band 3) in the renal collecting duct of the common marmoset

The purpose of this study was to determine the expression and distribution of band 3 in the collecting duct and connecting tubules of the kidney of the marmoset monkey (Callithrix jacchus), and to establish whether band 3 is expressed in type A intercalated cells. The intracellular localization of band 3 in the different populations of intercalated cells was determined by double-labeling immunohistochemistry. Immunohistochemical microscopy demonstrated that band 3 is located in the basolateral plasma membranes of all type A intercalated cells in the connecting tubule (CNT), cortical collecting duct (CCD), and outer medullary collecting duct (OMCD) of the marmoset. However, type B intercalated cells and non-A/non-B intercalated cells did not show band 3 labeling. Electron microscopy of the CNT, CCD and OMCD confirmed the light microscopic observation of the basolateral plasma membrane staining for band 3 in a subpopulation of interacted cells. Basolateral staining was seen on the plasma membrane and small coated vesicles in the perinuclear structure, some of which were located in the Golgi region. In addition, there was no labeling of band 3 in the mitochondria of the CNT, CCD and in OMCD cells. The intensity of the immunostaining of the basolateral membrane was less in the CNT than in the CCD and OMCD. In contrast, band 3 immunoreactivity was greater in the intracellular vesicles of the CNT. From these results, we suggest that the basolateral Cl^-/HCO₃^- exchanger in the monkey kidney is in a more active state in the collecting duct than in the CNT.     

Studies on the Susceptibility of Water Buffaloes to Leptospira

Eight mature farming type, Taiwan, water buffaloes were inoculate with L. australis A while six received L. canicola. Before inoculation all animals were negative to the microscopic-agglutination test (agglutinationlysis test) using the above species as antigen.

No sign of clinical leptospirosis was observed although four animals developed temperatures.

Cultures made from buffalo blood, kidneys and urine and from blood of guinea pigs inoculated with kidney emulsion and urine from the inoculated buffalo were all negative for leptospiral organisms.

Blood samples drawn from the water buffalo 2, 3 and 4 weeks post inoculation were negative to the microscopic-agglutination test except for one animal. Blood from the animal taken two weeks post-inoculation was positive at 1:100 dilution with L. australis A antigen but that taken at 3 and 4 weeks was negative.

     

Serum Fractions Inhibitory to the Growth of Leptospires

It is known that the growth inhibitory substance of animal sera on Leptospires exists in the albumin fraction. Since the globulin fraction obtained from animal sera having growth inhibitory property may support, though variable individually, some degree of leptospiral growth, it may be added, with 5% of pooled rabbit serum, to the medium to be used for the propagation of Leptospires.