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101.
102.
Exotoxins produced by Actinobacillus (A.) pleuropneumoniae (Apx) play major roles in the pathogenesis of pleuropneumonia in swine. This study investigated the role of ApxI in hemolysis and cellular damage using a novel apxIA mutant, ApxIA336, which was developed from the parental strain A. pleuropneumoniae serotype 10 that produces only ApxI in vitro. The genotype of ApxIA336 was confirmed by PCR, Southern blotting, and gene sequencing. Exotoxin preparation derived from ApxIA336 was analyzed for its bioactivity towards porcine erythrocytes and alveolar macrophages. Analysis results indicated that ApxIA336 contained a kanamycin-resistant cassette inserted immediately after 1005 bp of the apxIA gene. Phenotype analysis of ApxIA336 revealed no difference in the growth rate as compared to the parental strain. Meanwhile, ApxI production was abolished in the bacterial culture supernatant, i.e. exotoxin preparation. The inability of ApxIA336 to produce ApxI corresponded to the loss of hemolytic and cytotoxic bioactivity in exotoxin preparation, as demonstrated by hemolysis, lactate dehydrogenase release, mitochondrial activity, and apoptosis assays. Additionally, the virulence of ApxIA336 appeared to be attenuated by 15-fold in BALB/c mice. Collectively, ApxI, but not other components in the exotoxin preparation of A. pleuropneumoniae serotype 10, was responsible for the hemolytic and cytotoxic effects on porcine erythrocytes and alveolar macrophages.  相似文献   
103.
An 8‐week trial was conducted to assess the feasibility of replacing soybean meal (SBM) by lupin seed meal (LSM) in simulated commercial diets for juvenile tilapia starting at 0.3 g. Of the dietary protein (26% crude protein), 3.45% was from fishmeal and the rest came from the vegetable protein sources. The protein source of the control (C) diet came mainly from SBM and none (0%) from LSM. For the other diets, 33%, 67%, or 100% of the SBM protein was replaced by protein from either whole or dehulled LSM. One further diet was used: AW100, where alkaloid of the whole lupin seed was reduced. Survival, growth, and feed performance were compared among seven orthogonal contrasts to determine the effects of replacing SBM with whole LSM or dehulled LSM, and of reducing the alkaloid content. No differences in survival were found among all contrasts. No differences in fish growth and feed performance were found between feeding diet C and the other six diets ((whole, dehulled) × (33, 67, and 100)). Dehulled LSM diets resulted in better growth and feed performance than the whole LSM diets. Partial replacement of SBM by either dehulled LSM or whole LSM in diets obtained better growth and feed performance than total replacement. The AW100 diet resulted in equal fish growth but better feed performance than the W100 diet. This study concluded that partial, but not total, replacement of soybean protein with lupin seed protein in juvenile tilapia diets resulted in better, or at least equal, growth and feed performance. Dehulling further enhanced the growth and performance of LSM. Alkaloid removal improved feed performance but not the growth.  相似文献   
104.
Surface application of ammonium sulfate (AMS) as S source to soils with pH ≥7.0 is subjected to ammonia (NH3) volatilization. However, AMS volatilizes less NH3 than urea does. In soils with pH <7.0, unlike urea, very little NH3 volatilization from AMS occurs. The associated N with AMS may enhance early biological N fixation by leguminous crops as compared to S sources without N such as polyhalite.  相似文献   
105.
106.
Particleboard specimens with various particle sizes were conditioned into two ranges: low and high moisture content. One set was investigated for internal bond (IB) strength and acoustic emission (AE) events during tensile tests perpendicular to the plane and the other for ultrasonic wave transmission characteristics in the thickness direction. The particleboard structural mechanics were changed as a result of the moisture effect. Specimens conditioning to higher moisture content had lower IB strength and lower cumulative acoustic emission event counts (T AE). The decrease in IB strength indicated that the irreversible thickness swelling was seen when recovery forces of the particles exceed the restraining action of the adhesive. This was attributed to stress release, which resulted in internal failure of the board. The change in the internal structure caused an increased stress level at the initiation of AE generation. No events were recorded before this stress level, obeying theKaiser effect. The decrease inT AE was not only related to the decrease in IB strength but was also affected by the transformation (attenuation) of the AE signals during IB tests according to the mesh size used.Part of this paper was presented at the 45th and 50th Annual Meetings of the Japan Wood Research Society, Tokyo and Kyoto, 1995 and 2000, respectively  相似文献   
107.
余建章 Palm.  RG 《作物学报》1989,15(4):397-304
该新三体于1983年发现,1984年鉴定。新三体的超数染色体为带随体的染色体,命名为Trisomic E(简写为 Tri E),其四体应称为随体四体(Satellite tetrasomic)。非整倍体的原始真叶较小,生长势较弱,单株结荚数比二倍体少得多。控制茸毛色的基因(t)可以定位在新三体的超数染色体上。  相似文献   
108.
The wet scrubbing combined SOx/NO removal system is one ofthe advanced air pollution control devices. This study tries tounderstand the kinetics of the absorption in the system. The absorption of SO2 and simultaneous absorption of SO2 and NO, whose concentrations are typical for flue gases emittedfrom coal-fired power plants, in a stirred tank reactor with NaClO2/NaOH solutions were carried out at 50 °C.The liquid-side and gas-side mass transfer coefficients of the system were determined. The results indicate that the absorptionof SO2 is completely gas-film controlled if the NaOH concentration is greater than 0.1 M or the NaClO2 concentration is greater than 0.2 M. Adding SO2 would decrease the absorption rate of NO; however, the addition of NO has no effect on the absorption rate of SO2. The existence of O2 has no significant effect on the absorption rate of SO2 and NO in the combined SOx/NO removal tests.  相似文献   
109.
NO X is a major pollutant that causes acid deposition and photochemical smog. A large amount of NO X is emitted from combustion sources such as power plants. As some articles have indicated, NO X removal with NaClO2 solution in an absorption column is an effective control approach. In this approach, first insoluble NO is oxidized into water-soluble NO2 under acidic conditions, then NO2 is removed in alkaline NaClO2 solutions. The results indicate that the reaction rate constant is 9.1×104 (L)4.4/cm6/s/mol2.4 in the first absorption column with acidic conditions, and the reaction orders with respect to NO and NaClO2 are 1.4 and 2, respectively. In the second absorption column with alkaline conditions, the reaction rate constant is 3.2×107 (L)5.2/cm6/s/mol3.2 and the reaction orders with respect to NO and NaClO2 are 1.6 and 2.5, respectively. The activation energies in the first and second absorption column are 71.8 and 139.6 kJ/mol, respectively.  相似文献   
110.
The objectives of this study were to develop a high-performance liquid chromatography method for analysis of carotenoids in spear shrimp shells (Parapenaeopsis hardwickii) and to compare the extraction efficiency of carotenoids by supercritical carbon dioxide (SCD) and solvents. Results showed that the most appropriate HPLC method was accomplished by employing a Cosmosil 5C18-AR-II column and a mobile phase of methanol-dichloromethane-acetonitrile (90:5:5, v/v/v) (A) and water (100%) (B) with the following gradient elution: 92% A and 8% B in the beginning, decreased to 4% B in 9.5 min, 1% B in 26 min, 0% B in 35 min, maintained for 25 min, and returned to 92% A and 8% B in 61 min. All-trans-astaxanthin and its two cis isomers, as well as five astaxanthin monoesters and 11 diesters were resolved within 60 min with a flow rate at 2 mL/min and detection at 480 nm. Astaxanthin diesters were found to contain 12 fatty acids, of which palmitic acid and stearic acid constituted a large portion, whereas astaxanthin monoesters were found to contain 10 fatty acids with arachidonic acid dominating. Solvent extraction could generate a higher content of trans-astaxanthin and astaxanthin esters, while SCD extraction could produce greater levels of 9-cis-astaxanthin and 13-cis-astaxanthin.  相似文献   
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