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1.
目的比较BPS注塑树脂和热凝基托树脂表面细菌粘附能力的大小。方法将BPS注塑树脂和热凝基托树脂试件进行细菌体外粘附实验,采用菌落形成单位计数法测定血型链球菌、粘性放线菌和白色念珠菌粘附量的大小。结果培养24h、48h、168h后,各BPS注塑树脂试件组的细菌粘附量均少于热凝基托树脂试件组。结论BPS注塑树脂较热凝基托树脂更能减少血型链球菌、粘性放线菌和白色念珠菌在其表面的粘附。 相似文献
2.
The ultrastructure of the resin secreting cells of root ductsof young Pinus halepensis seedlings was studied. It is suggestedthat the endoplasmic reticulum (ER) in addition to taking partin resin synthesis also plays a role in transporting the resinfrom the plastids, mitochondria and nuclear envelope to theplasmalemma. By fusing with the plasmalemma the ER releasesthe resin to the outside of the protoplast. The resin producedin the ground cytoplasm and by the Golgi apparatus seems tobe eliminated by plasmalemma invaginations. Pinus halepensis, resin secretion, root ducts, endoplasmic reticulum 相似文献
3.
Three peptide fragments selected from the NS-1 region of hepatitis C-viral polyprotein (Leu-Ile-Asn-Thr-Asn-Ala-Ser-Trp-His-Ala-Asn-Arg-Thr-Ala-Leu-Ser Asn-Asp Ser-Lys Leu Asn Thr-Gly Ala NH(2), Leu-lle Asn Thr Asn Ala Ser-Trp-His-Ala-Asn-Arg-Thr Ala NH(2) and Leu-Asn-Cys(Acm)-Asn-Asp-Ser-Leu-Asn-Thr-Ala-NH(2)) have been synthesized on PS-BDODMA resin. The synthetic capability of the resin PS-BDODMA resin was compared with Merrifield resin. The peptides were synthesized by the stepwise fluoren-9-yl methoxycarbonyl (Fmoc) solid-phase method. The synthesized peptides were purified by HPLC and the identity of the peptides was established by mass spectrum and amino acid analysis. The synthesis of these peptides illustrates the application of the PS-BDODMA resin for the synthesis of long chain peptides in high yield and homogeneity compared to the Merrifield resin. 相似文献
4.
5.
Summary Changes in needle nitrogen and resin acid concentrations in young Scots pine trees fertilized with ammonium nitrate were followed over 3 years. Sawfly larvae (Neodiprion sertifer) were reared on fertilized and control trees the year after fertilization. Both nitrogen and resin acid concentrations increased in fertilized trees. The fact that resin acid concentrations increased contradicts predictions of the carbon/nutrient balance hypothesis. We suggest that needle resin-acid concentrations are limited more by the size of the resin ducts than by the availability of substrate for resin acid synthesis, and that the formation of resin ducts is limited by the availability of nitrogen. A modification of the carbon/nutrient balance hypothesis, relating compartment formation to allelochemical synthesis, is discussed. Performance of sawfly larvae was not affected by fertilization treatment, probably because concentrations of nitrogen (positively affecting performance) and resin acids (adversely affecting performance) increased simultaneously in fertilized trees. Thus, the results of this study do not support the notion that fertilization increases the resistance of trees to needle-eating insects. 相似文献
6.
发酵液中L-色氨酸分离纯化工艺研究 总被引:5,自引:0,他引:5
通过静态吸附实验,考察了温度、pH值对001×7阳离子交换树脂平衡吸附量的影响,并测定了吸附动力学曲线。通过动态实验,测定了动态吸附曲线和洗脱曲线。最后确定了001×7阳离子交换树脂分离纯化L-色氨酸的最佳工艺条件:用001×7阳离子交换树脂吸附L-色氨酸,以浓度为2 mol.L-1氨水进行洗脱,收集的流份经D315阴离子交换树脂脱色,浓缩结晶后得L-色氨酸成品,总提取率为73.0%。 相似文献
7.
Growth and defence in young pine and spruce and the expression of resistance to a stem-feeding weevil 总被引:1,自引:0,他引:1
Defence in young trees has been much less studied than defence in older ones. In conifers, resin within ducts in bark is an
important quantitative defence, but its expression in young trees may be influenced by developmental or physical constraints
on the absolute size of the resin ducts as well as by differential allocation of resources to growth and resin synthesis.
To examine these relationships, we used nitrogen fertilisation of 1- and 2-year-old pine and spruce to produce trees of different
sizes and measured the effect on the number and size of resin ducts and the amount of resin they contained. All of these variables
tended to increase with stem diameter, indicating a positive relationship between resin-based defence and growth of 1- and
2-year-old trees. In pine, however, the mass of resin flowing from severed ducts was much lower relative to duct area in 1-
than in 2-year-old trees, suggesting that the older trees allocated a higher proportion of the carbon budget to resin synthesis.
Resin-based defence in 1-year-old pines appears to be both positively related to growth and resource limited. In spruce, resin
production was generally lower, and age-related differences were not observed, suggesting that resin-based defence is less
important in this species. Bio-assays of 2-year-old trees with the pine weevil, Hylobius abietis, emphasised the importance of resin as a defence against this bark feeding insect. Nitrogen fertilisation had a limited influence
on resistance expression. One-year-old trees remained susceptible because of their small size, low resin production and limited
response to fertilisation. The strong growth response of 2-year-old trees to fertilisation increased resin-based defence,
but most spruce trees remained susceptible, while most pines were resistant at all levels of fertilisation. 相似文献
8.
Summary Prediapause larvae of the checkerspot butterfly Euphydryas chalcedona were raised from hatch until entrance into diapause on artificial diets. The proportions of protein and host plant leaf resin differed among the diets. Larval size growth rates and mortality were monitored and overall rates and efficiencies of food use were computed.Larval survivorship, growth rate and size of larvae at idapause were significantly enhanced by increasing dietary protein content, particularly over the range found in leaves of the host plant. In contrast, an increasing dietary content of Diplacus aurantiacus leaf resin significantly depressed larval surviviorship, growth rates and size of larvae at diapause. A simple dosedependent interaction was observed between the effects of dietary leaf resin and protein on larval success. Dietary content of leaf resin and protein significantly influenced some measures of food utilization efficiency (ECI and ECD), but not others (AD and NUE).The negative interaction between the effects of dietary leaf resin and protein content suggests the leaf resin phenolic compounds reduce the availability of protein to the larvae. The results for efficiency indices of larval food use are potentially in conflict with this interpretation.The influence of host plant leaf resin and protein on larval success, coupled with the relation between photosynthesis and leaf nitrogen content, are consistent with the hypothesis that productivity can be enhanced by herbivore deterrence resulting from leaf resin production. 相似文献
9.
Sulfonation of polyvinylidene difluoride (PVDF) resin was achieved by incubation of the resin with sulfuric acid at a moderately high temperature. The sulfonated PVDF (SPVDF) resin was studied for its ability to extract restriction enzymes from DNA digestion solutions. The SPVDF resin was effective in adsorbing restriction enzymes such as EcoRI and BamHI and the extraction procedure was easy and simple to perform. The adsorption depended upon the amount of the resin added. We found that 1 mg of the SPVDF resin could completely remove all restriction enzyme activity routinely used in DNA digestion within 2 min after its addition. Treatment of a digestion solution with the SPVDF resin did not change the reaction solution and the same digestion buffer could be used for another digestion of the same DNA with other enzymes. We also found that, in comparison with normal PVDF, the SPVDF resin adsorbed less DNA, resulting in less loss of DNA in the extraction step. The potential application of the SPVDF resin in other procedures of molecular cloning and enzyme purification is discussed. 相似文献
10.
The potential for the feedback inhibition of indole alkaloid synthesis was investigated by spiking suspension cultures of Catharanthus roseus with 0, 9, or 18 mg/L ajmalicine on day 0. The production of ajmalicine, catharanthine, and serpentine were inhibited in a dose-dependent manner. The inhibition was transient as the exogenous ajmalicine was ultimately either metabolized in the medium or within the cell. The addition of neutral resin has previously been shown to enhance ajmalicine production. To minimize product inhibition and product metabolism, Amberlite XAD-7 resin was added to immobilized cultures of C. roseus starting on either day 0, 5, or 15, and fresh resin was exchanged for spent resin every 5 days. The addition of resin did not decrease the viability of the culture. Growth was reduced only in cultures with resin added on day 0. Alkaloid production was enhanced to different extents by the timing of resin addition, suggesting that feedback inhibition or product metabolism was present throughout the culture period. Ajmalicine recovery was nearly 100% when the resin was added initially either on day 0 or day 5. Ajmalicine recovery was reduced to 55% when the resin was added later in the culture period starting on day 15, presumably because of resin saturation or the inaccessibility of alkaloids trapped in the vacuole. Delaying the addition of XAD-7 resin until 5 days after the start of the culture resulted in the highest improvement in ajmalicine production, i.e approximately 70% and also resulted in the complete recovery of ajmalicine from the cell. 相似文献
11.
The vertical resin ducts in Corsican pine sapwood made the majorcontribution to resin yields as assessed by sampling tubes.Resin yields from roots appeared to be influenced by soil physicalfactors which affect vertical duct frequency. Yields from stemswere not affected by soil pH, as had been suggested previously,and the greater resistance of pines to Heterobasidion annosumattack on acidic soils does not seem to be due to an effectof soil pH on the resin response. Considerations of the infectionhabit suggested that the tube sampling method did not measurethe most relevant parameters of resin production in the contextof host resistance. 相似文献
12.
油松茎次生木质部中树脂道的发育过程和组织化学研究 总被引:4,自引:0,他引:4
利用组织化学方法对油松茎次生木质部树脂道发育过程中上皮细胞内树脂滴和淀粉粒的动态变化进行了研究。发现在树脂道原始细胞阶段,每个原始细胞含淀粉粒较少,含树脂滴稀少。在树脂道形成阶段,淀粉粒数目较多,体积增大,树脂滴也呈递增趋势。在树脂道成熟阶段,淀粉粒数目变化不大,而体积明显变小,树脂滴的体积增大,数目减少。 相似文献
13.
目的:通过自体诱导信号分子抑制剂的生产获得部分分离纯化的酰化高丝氨酸内酯(AHL)抑制剂。方法:病原菌铜绿假单胞菌经摇床培养后获得AHL抑制剂,采用溶解度差异性和树脂进行分离纯化。结果:铜绿假单胞菌PAO1不仅分泌自体诱导信号分子,而且在生长的后期还合成一种信号分子抑制剂,该信号分子抑制剂对群体感应中的AHL类信号分子有明显的抑制作用;该抑制剂具有醇溶性和水溶性,采用乙醇溶解可以除去糖类和无机小分子等不溶于醇的物质;大孔吸附树脂不具有吸附抑制剂的能力,但可以除去醇溶性糖类物质;阴离子交换树脂能够吸附信号分子抑制剂,具有较好的分离效率。结论:获得了除去大部分杂质,得到部分分离纯化的AHL抑制剂。 相似文献
14.
A Sticky Affair: Resin Collection by Bornean Stingless Bees 总被引:2,自引:0,他引:2
Plant resins are used by stingless bees for nest construction and maintenance. To reveal factors that influence the bees' decision about where and when to collect resin, resin collection was studied in ten stingless bee species (Apidae, Meliponini) collecting resin at natural and artificially induced wounds of nine tree species in Borneo. Artificially induced wounds were found by bees within 1–2 d. The number of foragers at artificial wounds increased during the subsequent 5 d until resin secretion stopped or the resin hardened. At natural resin wounds, species identity and number of foragers remained constant during the observation period. Bees collected resin from some trees and ignored others. Agathis borneensis (Araucariaceae) was the most attractive resin source. The bees' visitation rate did not correlate significantly with resin wound size. Inter- and intraspecific aggression occurred at ten resin wounds. In Tetragonilla collina and Tetragonula melanocephala , we additionally recorded resin intake at colony entrances. The proportion of workers retuning with resin varied considerably between colonies. We observed attacks by ants at three of our eight focal colonies, which resulted in a significant increase in resin intake while the nest was under attack and until 1–2 d after the attack had stopped. The increase in resin collection triggered by ant attacks was even stronger than the increase following a manual destruction of the nest entrance tube. 相似文献
15.
Jian-Hui Ye Jing Jin Yi-Wen Luo Xian-Yang Luo Xin-Qiang Zheng Hui-Ling Liang Jian-Liang Lu Yue-Rong Liang 《Biotechnology and Bioprocess Engineering》2011,16(2):256-263
L-Theanine, a bioactive compound in tea, was isolated from tea solution using cation exchange resin no.732. The adsorption
of L-theanine by cation exchange resin no.732 fit the Langmuir isotherm model and was a monolayer molecular interaction process.
Thermodynamic studies revealed that the adsorption of L-theanine by resin no.732 was an exothermic and spontaneous physically
driven process. The adsorption capacity was influenced by temperature, initial concentration, and pH. The L-theanine adsorption
capacity under conditions at room temperature, pH 4.73, and initial L-theanine concentration 18 g/L was 241.731 ± 3.679 mg/g.
The Thomas model was fit to describe the column adsorption data at different flow rates and initial concentrations. The L-theanine
adsorbed by resin no.732 could be desorbed by 0.134 mol/L Na2HPO4 aqueous solution with a recovery rate of 84.96%. These findings indicate that resin no.732 was a promising material for isolating
L-theanine from tea solution. 相似文献
16.
The diterpenoid kaurenoic acid is the main component of the resin from the medicinal plant Pseudognaphalium vira vira. As some diterpenoids have antimicrobial properties, the effect of this resin and the kaurenoic acid on soil bacteria was studied. The resin of P. vira vira and purified kaurenoic acid were two to four times more effective as antibacterial agents with Gram-positive than with Gram-negative soil isolates. The chemical stability of kaurenoic acid and the antibacterial activity of both the resin and the diterpenoid were studied in microcosms containing plant-associated soil. After 15 days of incubation, the diterpenoid was stable, as determined by 1H nuclear magnetic resonance and thin-layer chromatography, and soil extracts still exhibited antibacterial activity. However, after 30 days of incubation, loss of antibacterial activity of soil extracts correlated with removal or chemical modification of kaurenoic acid. The effect of the resin or this diterpenoid on the soil bacteria community was analyzed by the terminal restriction fragment length polymorphisms technique. After 15 days of incubation, the resin and the pure compound caused significant changes in the soil bacterial community. The relative abundance of specific bacterial groups was differentially affected by the resin components, being the effects with the resin stronger than with the kaurenoic acid. After 30 days of incubation, these changes mostly reverted. These results indicate that a plant resin containing diterpenoid compounds plays a significant role controlling specific groups of microorganisms in the soil associated with the plant. 相似文献
17.
Characterization of soil phosphorus by anion exchange resin adsorption and P32-equilibration 总被引:4,自引:1,他引:3
Summary Adsorption of phosphate by the anion-exchange resin Dowex-2 was investigated. The resin adsorbed small quantities of P from solution quantitatively. The rate of P-adsorption by resin agitated in solution was proportional to the P-concentration in solution, and was independent of the rate of diffusion of adsorbed P in the resin. When 1 g of soil was shaken continuously with 1 g of resin in 100 ml of water, the rate of P-adsorption by the resin was controlled by the rate of P-release from the soil. Quantities of P adsorbed from soil by resin after different lengths of time were less than those equilibrated with P32 during the same time intervals. The curves showing quantity of P adsorbed vs. time could be satisfactorily described by the hypothesis that there were three simultaneous reactions differing in rate, each reaction being first-order with respect to P. The same was true of the P32-equilibration data, except that the rate of the slowest reaction was apparently independent of time. In a group of 16 soils, the correlation between P adsorbed by the resin in 2 hours and P-availability to plants in the greenhouse, measured by the isotope-dilution method of Fried and Dean, was 0.95. The corresponding correlation between P extracted by the 0.25N HCl — 0.03N NH4F extractant of Bray and Kurtz was 0.91.Joint contribution from the Iowa Agricultural Experiment Station and the Eastern Soil and Water Management Section, U.S. Department of Agriculture. Journal Paper No. J-2639 of the Iowa Agricultural Experiment Station, Ames, Iowa. Project No. 1183.Graduate Assistants, Professor of Soils, and Associate Professor of Chemistry, respectively. 相似文献
18.
The purpose of this research was to mask the bitter taste of Diphenhydramine Hydrochloride (DPH) using cation exchange resins.
Indion 234 and Tulsion 343 that contained crosslinked polyacrylic backbone were used. The drug resin complexes (DRC) were
prepared by batch process by taking drug: resin ratios 1:1, 1:2, and 1:3. The optimum drug: resin ratio and the time required
for maximum complexation was determined. The drug resinates were evaluated for the drug content, taste, micromeritic properties
drug release and X-ray diffraction (PXRD). Effervescent and dispersible tablets were developed from optimum drug: resin ratios
of 1:2 and 1:1. The formulations were evaluated for uniformity of dispersion, disintegration time, and in vitro dissolution. The X-ray diffraction study confirmed the monomolecularity of entrapped drug in the resin beads. The taste evaluation
depicted the successful taste masking of DPH with drug resin complexes. The drug release of 95% in 15 min was observed for
effervescent and dispersible tablets. 相似文献
19.
Infiltrating and Embedding Tissues with Mixtures of Polyethylene Glycols and Polyvinylacetate Resins
The use of water-soluble polyethylene glycol polymers (Carbowax, Hydrowax) as embedding media can be extended and facilitated by incorporating a water insoluble polyvinylacetate resin, AYAF (Union Carbide Co.). A combination of 7.5% resin added by heating to a 3:1 mixture of polyethylene glycols 1540 and 4000 gives blocks which may be cut at 2-3 μ. Sections can be floated and properly expanded on an ordinary water bath in a manner which may be impossible with Carbowax alone because of section fragility. This may require judicious adjustment of surface tension by the prior addition of minute quantities of the wax. On water, polyethylene glycol dissolves out of tissues, which remain supported by the resin. After attachment to albumen-coated slides, residual resin may, at option, be removed by a 1-2 min immersion in methyl alcohol without visible impairment of fat content. Abopon is used for mounting. The method appears suitable for the study of intracellular lipids, particularly in tissues which cannot be conveniently handled after Carbowax alone. 相似文献
20.