Inhibitory action of dissolved humic substances on the growth of soil bacteria degrading DDT     

Yoshiki Fujimura  Arata Katayama  Shozo Kuwatsuka 《Soil Science and Plant Nutrition》2013,59(3):525-530

Abstract

Dissolved humic acid (HA) and fulvic acid (FA) prepared from a Dando brown forest soil (Typic Dystrochrept) inhibited the growth of soil bacteria degrading DDT (1,1,1-trichloro-2,2-bis(4-chlorophenyl)ethane) in the culture. The population of DDT-degrading Gram-variable rod Bll6 decreased by the application of both HA and FA, suggesting the presence of bactericidal effect. Such inhibitory effect was stronger for HA and resulted in a lower degrading activity of DDT in the culture of Bll6. No inhibitory effect was observed on the growth of DDT-degrading Bacillus sp. B75. The electron spin resonance spectra showed the presence of organic free radicals in both HA and FA. The relative concentration of the radicals was higher in HA. Storage of HA solution for 3 months at 4°C decreased the concentration of the radicals as well as the inhibitory action. The addition of catalase decreased the inhibitory effect of humic acid. It is suggested that a hydroxy radical, which is derived from free radicals of humic substances, is involved in the inhibition of bacterial growth and degradation of DDT.  相似文献   

Behavior of phenolic substances in the decaying process of plants     

Haruo Shindo  Shozo Kuwatsuka 《Soil Science and Plant Nutrition》2013,59(2):221-232

The behavior of phenolic substances in the decaying process of rice straw, ladino clover, and fanen leaves of red oak under moist conditions, and also of rice straw under various conditions were compared in the laboratory. The amounts of phenolic substances, divided into either humic acid and fulvic acid fractions, or ether-extractable, butanol-extractable and organic solvent-unextractable fractions, and the amounts of individual phenolic acids were periodically determined during incubation for 150 days. The following results were obtained.

1) The amounts and behavior of phenolic substances in various fractions differed considerably among the plant materials. The total amount of phenolic substances was remarkably larger in red oak leaves than in the others during the whole period of incubation. The amounts of phenolics in the fulvic acid fraction changed to a larger extent than those in the humic acid fraction during the decaying process of plant materials. The changes in total amount of phenolics in decaying red oak leaves and ladino clover were mainly due to changes in the level of relatively hydrophilic phenolics in the fulvic acid fraction, but the changes in decaying rice straw were mainly due to changes in the level of relatively lipophilic phenolics.

2) Rice straw and ladino clover, especially the former, contained large amounts of p-coumaric and ferulic acids, but these decreased rapidly in the early stage of the decaying process. The amounts in red oak leaves were small, but did not decrease markedly during incubation.

3) The changes in amounts of phenolics in both humic acid and fulvic acid fractions in the decaying process of rice straw were largely influenced by temperature, moisture, and pH, but not to a large extent by C/N ratio and the presence of soil. At higher temperatures under moist conditions, phenolic substances disappeared rapidly. Also, acidification of the system inhibited the degradation process.  相似文献   

Scanning electron microscopy of the nuclei isolated from chicken liver     

S Arai  Y H Nakanishi 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1988,50(4):946-948

  相似文献   

Changes of glycolytic enzyme activities and plasma insulin levels in diabetic herbivorous voles and KK mice     

T Arai  M Mochizuki  Y Oki 《Nippon juigaku zasshi. The Japanese journal of veterinary science》1988,50(4):859-864

  相似文献   

Changes in hepatic lipogenic enzyme activities in voles and mice treated with monosodium aspartate.     

T Arai  Y Hasegawa  Y Oki 《Research in veterinary science》1992,53(2):247-249

Changes in activities of hepatic lipogenic enzymes, ATP citrate lyase and acetyl-CoA carboxylase, were measured in voles and C57BL mice following neonatal administration of monosodium aspartate (MSA). Hepatic lipogenic enzyme activities in voles were considerably lower than those in mice; these low activities were considered to be one of the characteristics of voles as a herbivore. In the MSA-treated voles and mice, the plasma insulin concentrations increased significantly. The MSA-treated mice showed remarkable obesity and increased lipogenic enzyme activities. In the MSA-treated voles, signs of obesity were not observed and hepatic ATP citrate lyase activity increased significantly; acetyl-CoA carboxylase activity did not increase.  相似文献   

Studies of foetuses from cows clinically affected with bovine leucosis     

Y. Kono  H. Sentsui  K. Arai  W. Irishio  A. Fujigaki 《Veterinary microbiology》1983,8(5):505-509

Five foetuses varying stages of gestation were recovered from cows showing clinical signs of infection with bovine leukaemia virus (BLV). No pathological changes were found in the foetuses although BLV was isolated from 2 of these foetuses. No antibody to BLV could be detected by virus-neutralisation or immunodiffusion (ID) techniques in these two foetuses, although neutralising antibody alone was detected in one of the other 3 foetuses which were all negative for virus.  相似文献   

Antibacterial Efficacy of Several Surgical Hand Preparation Products Used by Veterinary Students          下载免费PDF全文

Po‐Yen Chou  Aimie J. Doyle  Shiori Arai  Pierre J. Burke  Trina R. Bailey 《Veterinary surgery : VS》2016,45(4):515-522

  相似文献   

A Survey for the Microfilariae of the Canine Heartworm, Dirofilaria immitis, in the Calgary Region of Southern Alberta          下载免费PDF全文

Frimeth JP  Arai HP 《The Canadian veterinary journal. La revue veterinaire canadienne》1984,25(1):14-16

A blood survey for the prevalence of the microfilariae of the canine heartworm, Dirofilaria immitis was conducted in the Calgary area of southern Alberta between November 1977 and August 1979. A total of 514 blood samples was examined by the modified Knott's test. All of the samples were negative for D. immitis microfilariae. Wright's stained blood smears taken from 19 animals at the Calgary Zoo also proved negative. One smear from a male two-toed sloth (Choloepus didactylus) contained sheathless microfilariae which were distinguishable from those of D. immitis. These results, as well as mail survey data indicate that D. immitis is not endemic in the Calgary area.

It is recommended that the modified Knott's test be used for similar large scale sampling studies. In addition, it is suggested that the testing of both native and exotic zoo animals which could serve as definitive hosts of D. immitis be continued. These animals may become local sources of infection or introduce other species of microfilariae which will have to be differentiated from those of D. immitis.

  相似文献   

PCR-RFLP genotypes associated with quinolone resistance in isolates of Flavobacterium psychrophilum     

Izumi S  Ouchi S  Kuge T  Arai H  Mito T  Fujii H  Aranishi F  Shimizu A 《Journal of fish diseases》2007,30(3):141-147

A novel genotyping method for epizootiological studies of bacterial cold-water disease caused by Flavobacterium psychrophilum and associated with quinolone resistance was developed. Polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) was performed on 244 F. psychrophilum isolates from various fish species. PCR was performed with primer pair GYRA-FP1F and GYRA-FP1R amplifying the A subunit of the DNA gyrase (GyrA) gene, which contained the quinolone resistance determining region. Digestion of PCR products with the restriction enzyme Mph1103I showed two genotypes, QR and QS. The difference between these genotypes was amino acid substitutions at position 83 of GyrA (Escherichia coli numbering). The genotype QR indicated an alanine residue at this position associated with quinolone resistance in F. psychrophilum isolates. Of the 244 isolates tested in this study, the number of QR genotype isolates was 153 (62.7%). In isolates from ayu (n=177), 146 (82.5%) were genotype QR. With combination of this technique and previously reported PCR-RFLP genotyping, eight genotypes were observed in F. psychrophilum isolates. Using this genotyping system, the relationships between genotype and host fish species, or locality of isolation, were analysed and are discussed.  相似文献   

Physical and mechanical properties of wood after moisture conditioning   总被引：1，自引：0，他引：1  

Yutaka Ishimaru  Kazutoshi Arai  Masato Mizutani  Katsuhito Oshima  Ikuho Iida 《Journal of Wood Science》2001,47(3):185-191

Some properties of wood (hinoki:Chamaecyparis obtusa) moisture-conditioned by an adsorption process from a dry state and by two desorption processes (from a water-saturated state and from a state with a moisture content slightly below the fiber saturation point) were investigated. The moisture contents of wood conditioned by the adsorption process and by the desorption process continued to approach to one another for the moisture-conditioning period of over 50 weeks. Accordingly, sorption hysteresis should be regarded as a transitional phenomenon that occurs during the process of approaching the true equilibrium, which requires a long time. The wood conditioned by the desorption process beginning from a water-saturated state showed slightly smaller dimensions than those conditioned by the adsorption process with the same moisture content; however, the wood conditioned by the desorption process from a moisture content below the fiber saturation point showed slightly larger dimensions than those conditioned by the adsorption process. The wood conditioned by the adsorption process from a dry state showed a higher modulus of elasticity and modulus of rupture than did the wood conditioned from a water-saturated state with the same moisture content. The mechanical properties of the wood also varied based on the states at which the desorption process was started. This is a notable characteristic of the relation between the drying condition and the mechanical properties of wood.  相似文献