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1.
Summary Deactivation ofCandida
rugosa lipase was found to be complex. Hydrophobic interaction induced by iso-octane influenced the initial phase of deactivation, and increased the turn-over rate of the intermediate in the transition phase. After urea-treatment the structure of the last phase was not further influenced by thermal treatment, whereas that of initial phase was more sensitive to temperature change. Charge interaction was important in maintaining the structure during the deactivation, and especially anion charge might be a major factor. 相似文献
2.
Bound atrazine was detected inElodea canadensis by an improved immunohistochemical fluorescence procedure using anti-triazine antibodies from rabbits, biotin-labelled anti-rabbit
immunoglobulin G and streptavidin-phycoerythrin conjugate. Whereas no labelling was found in control plants grown in charcoal-filtered,
atrazine-free water, the labelling of plants obtained from their natural habitat and grown in tap water was sometimes nearly
as high as in samples loaded with atrazine. The efficiency of the immunofluorescence procedure was compared using several
antisera obtained by immunizing with different hapten conjugates and purified by various purification methods. The best results
were observed with the atrazine analogue ametryn sulfoxide, which was coupled to bovine serum albumin for immunization and
to Sepharose for immunoaffinity chromatography. The procedure described in this paper may serve as a general tool for detecting
bound pesticide residues in plant material.
Dedicated to Professor Hans Mohr on the occasion of his 60th birthday 相似文献
3.
The effects of gamma irradiation on the survival and development of Clonorchis sinensis metacercariae 总被引:1,自引:0,他引:1
The effects of gamma irradiation on the survival and development of C. sinensis metacercariae were studied to evaluate the feasibility of irradiation as a control measure for clonorchiasis. Pseudorasbora parva were collected at an endemic river of clonorchiasis and were used for irradiation of the fluke in three schemes. The first (Scheme 1) was irradiation of the isolated metacercariae from the fish followed by infection to experimental rats. The second (Scheme 2) was irradiation of the fish, and then the metacercariae were isolated and infected to rats. The third (Scheme 3) was irradiation on the rat livers after infection with normal metacercariae. Irradiation doses varied from 5 to 100 Gy for Schemes 1 and 2, and 10 to 25 Gy for Scheme 3. The rats were sacrificed 2 to 6 weeks after infection. In Scheme 1, the metacercariae irradiated at 50 Gy failed to survive in the rats after 2 or 6 weeks. However, 1 to 44% of the metacercariae irradiated at 5-30 Gy survived. The estimated LD50 of Scheme 1 was 16.5 Gy. The flukes irradiated in Scheme 2 survived better than those in Scheme 1. The average worm recovery rate in 50 Gy was 28%(7-39% individually). Increasing the dose up to 100 Gy brought a remarkably low survival rate of an average 1%(0-3% individually). The LD50 of Scheme 2 was 47.5 Gy. Worm recovery rates in the 10 Gy group of Scheme 3 were 21-39%, and those in the 25 Gy group were 2% and 34%. Although the metacercariae were irradiated, all of the recovered worms were morphologically normal.(ABSTRACT TRUNCATED AT 250 WORDS) 相似文献
4.
K S Park D H Sohn R L Veech B J Song 《Biochemical and biophysical research communications》1992,185(2):676-682
Pentoxyresorufin O-depentylase activity, mainly associated with phenobarbital-inducible cytochrome P450IIB1 (designated CYP2B1), was increased after a single treatment of pyridine (250 mg/kg, i.p.), and further increased by repeated treatments for 5 days. The catalytic activity and immunoreactive protein of CYP2B recognized by polyclonal antibodies were significantly induced by a relatively high dose of pyridine (250 mg/kg, i.p.) while ethanol-inducible cytochrome P450IIE1 (CYP2E1) could be induced by a low dosage (25 mg/kg, i.p.). Unlike CYP2E1 induction without changing its mRNA level, the induction of CYP2B by pyridine was accompanied by an elevation of its mRNA, indicating a pre-translational activation of this enzyme. These results indicate that pyridine induces various isozymes of cytochromes P450 by different induction mechanisms. 相似文献
5.
Summary A heterologous gene from bloodsucking leech for anticoagulant, hirudin, has been expressed in the methylotrophic yeast Hansenula polymorpha. The addition of 1%(v/v) soybean oil to the medium as a stabilizer enhanced the expression of the hirudin gene in H. polymorpha with MOX promoter. The production of hirudin in the medium with soybean oil was 320mg/L in a 5L fermenter. 相似文献
6.
Changes in Cellular Fatty Acid Composition of Cephalosporium acremonium during Cephalosporin C Production
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Young-Sun Sohn Keun-Cheol Lee Young-Hwan Koh Gwang-Hoon Gil 《Applied microbiology》1994,60(3):947-952
Cephalosporium acremonium was cultivated in fermentation medium containing sucrose or methyl oleate as a carbon source for cephalosporin C production. The level of antibiotic production was 48 g of cephalosporin C per liter under optimum conditions when methyl oleate was used. The C18:1 (oleic acid) methyl ester appeared to be utilized faster than the C18:2 (linoleic acid) methyl ester in fermentation broth. Physiological characteristics of C. acremonium were investigated by determining the fatty acid composition of the total cellular free lipid. Significant changes in cellular fatty acid composition occurred during inoculum cultivation and fermentation. The percentage of C18:1 increased from 19.1 to 38.5%, but the percentage of C18:2 decreased from 56.7 to 36.1%, and there was an increase in pH during inoculum cultivation. The cellular fatty acid composition of C. acremonium grown in fermentation medium containing methyl oleate (methyl oleate medium) was significantly different from that in fermentation medium containing sucrose (sucrose medium). The major fatty acids detected were C16:0 (palmitic acid), C18:1, and C18:2. In methyl oleate medium, the ratio of C18:1 to C18:2 increased from 0.34 to 1.37, while the cell morphology changed from hyphae to arthrospores and conidia. In contrast, in sucrose medium, the ratio of C18:1 to C18:2 decreased from 0.70 to 0.43, and most of the cells remained hyphal at the end of fermentation. We observed that hyphae contained a higher proportion of C18:2 but arthrospores and conidia contained a higher proportion of C18:1. 相似文献
7.
Hyung-Joo Jin Jeong–Ha Kim Chul Hyun Sohn R.E. DeWreede Tae–Joo Choi G.H.N. Towers J.B. Hudson Yong–Ki Hong 《Journal of applied phycology》1997,9(4):383-388
Fifty-nine species of marine macrophytes from the coasts of British Columbia, Canada and Korea have been screened for the
presence of PCR inhibitors, namely inhibitors of Taq DNA polymerase. Eleven of the species displayed some inhibitor activity.
At the concentration of 5 μg of methanol extract in 25μL reaction mixture of PCR containing 1.5 unit of Taq DNA polymerase,
one (Ulva sp.) of 8 Chlorophyta, eight (Colpomenia bullosa, Ecklonia cava, Endarachne binghamiae, Fucus distichus, Hizikia
fusiformis, Sargassum confusum, Sargassum sagamianum, and Sargassum thunbergii) of 28 Phaeophyta, and one (Symphyocladia latiuscula)
of 34 Rhodophyta showed inhibition in PCR amplification. In the case of the water extract, two (Cladophora columbiana, Ulva
sp.) Chlorophyta, seven (Endarachne binghamiae, Fucus distichus, Hizikia fusiformis, Sargassum confusum, Sargassum sagamianum,
Sargassum horneri, Scytosiphon dotyi) Phaeophyta, no Rhodophyta and one (Phyllospadix scouleri) seagrass showed inhibition
in PCR amplification. the methanol fraction of Sargassum confusum and the water fraction of Fucus gardneri (mid–intertidal)
have been found to inhibit PCR at level as low as 0.5 μg in 25μL of PCR reaction mixture.
This revised version was published online in August 2006 with corrections to the Cover Date. 相似文献
8.
The tegumental ultrastructure of juvenile and adult Echinostoma cinetorchis (Trematoda: Echinostomatidae) was observed by scanning electron microscopy. Three-day (juvenile) and 16-day (adult) worms were harvested from rats (Sprague-Dawley) experimentally fed the metacercariae from the laboratory-infected fresh water snail, Hippeutis cantori. The worms were fixed with 2.5% glutaraldehyde, processed routinely, and observed by an ISI Korea DS-130 scanning electron microscope. The 3-day old juvenile worms were elongated and ventrally curved, with their ventral sucker near the anterior two-fifths of the body. The head crown was bearing 37-38 collar spines arranged in a zigzag pattern. The lips of the oral and ventral suckers had 8 and 5 type II sensory papillae respectively, and between the spines, a few type III papillae were observed. Tongue or spade-shape spines were distributed anteriorly to the ventral sucker, whereas peg-like spines were distributed posteriorly and became sparse toward the posterior body. The spines of the dorsal surface were similar to those of the ventral surface. The 16-day old adults were leaf-like, and their oral and ventral suckers were located very closely. Aspinous head crown, oral and ventral suckers had type II and type III sensory papillae, and numerous type I papillae were distributed on the tegument anterior to the ventral sucker. Scale-like spines, with broad base and round tip, were distributed densely on the tegument anterior to the ventral sucker but they became sparse posteriorly. At the dorsal surface, spines were observed at times only at the anterior body. The results showed that the tegument of E. cinetorchis is similar to that of other echinostomes, but differs in the number and arrangement of collar spines, shape and distribution of tegumenal spines, and type and distribution of sensory papillae. 相似文献
9.
Se-Wook Jung Tae-Kwon Kim Kwang-Woo Lee Yong-Hyun Lee 《Biotechnology and Bioprocess Engineering》2007,12(3):207-212
The catalytic properties of β-cyclodextrin glucanotransferase (β-CGTase) from alkalophilicBacillus sp. BL-12 specific for the intermolecular transglycosylation of stevioside were investigated. The molecular mass of purified
β-CGTase by ultra-filtration and β-cyclodextrin polymer affinity chromatography was estimated to be 90 kDa, which is high
compared to other known bacterial CGTases. The optimal pH and temperature were 9.0 and 50°C, respectively, and thermal stability
at 40°C was elevated 10-fold in the presence of 1% maltodextrin. The kinetic parameters of the new β-CGTase from alkalophilicBacillus sp. BL-12 indicate that it is more suitable for transglycosylation than the cyclization reaction. Maltodextrin was the most
suitable glycosyl donor for transglycosylation of stevioside. The transglycosylation of stevioside was carried out using 60
units of CGTase per gram of maltodextrin, 20 g/L stevioside as the glycosyl acceptor, and 50 g/L maltodextrin as the gycosyl
donor at 40°C for 6 h, and a conversion yield of stevioside as high as 76% was obtained. 相似文献
10.