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酿酒酵母生产谷胱甘肽分批发酵动力学研究 总被引:2,自引:0,他引:2
以麦芽汁为发酵培养基,对7.5L 自动发酵罐中酿酒酵母Y518 分批发酵生产谷胱甘肽的实验数据进行分析,建立谷胱甘肽分批发酵动力学模型。通过对符合菌体生长的Logistic 方程、产物生成的Luedeking-Piret 方程和基质消耗的物料衡算方程进行最优参数估计和非线性拟合,分别得到了相应的动力学模型和最佳模型参数值。对动力学模型的拟合曲线进行分析,发现模型的计算值与实验值能较好地拟合,表明本实验建立的分批发酵动力学模型能较好地反映谷胱甘肽分批发酵过程。 相似文献
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对短梗霉多糖分批发酵动力学进行了研究.基于Logistic方程和Luedeking-Piret方程分别建立了短梗霉多糖发酵过程菌体生长、产物合成及底物消耗随时间变化的数学模型,同时对实验值与模型进行了验证比较.结果表明,模型模拟计算结果与实验值能较好地吻合,该模型能较好地反映短梗霉多糖分批发酵的过程. 相似文献
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Trogoderma granarium is an important quarantine insect pest of economic importance worldwide. Insecticides are heavily used against this pest that can reduce its susceptibility levels, and if left unchecked, this could lead to misuse of insecticides. Here, the susceptibility of five field strains of T. granarium in comparison to a reference strain (Lab-TG) was determined against pirimiphos-methyl, permethrin and spinosad using dose-mortality bioassays. Based on lethal dose (LD50 and LD99) values, the Lab-TG strain was the most susceptible to all the insecticides in comparison to the field strains. In the case of field strains, LD50 values varied from: 17.68–31.97 mg/kg for pirimiphos-methyl, 20.50–42.47 mg/kg for permethrin, and 1.34–5.00 mg/kg for spinosad. Whereas LD99 values for pirimiphos-methyl, permethrin and spinosad of field strains varied from 409.07 to 730.24 mg/kg, 374.24–949.48 mg/kg, and 11.41–72.25 mg/kg, respectively. The resistance ratios (RR) at LD50 and LD99 levels were in the range of 13.71–24.78 and 39.33–70.21 fold for pirimiphos-methyl; 13.49–27.94 and 37.31–94.66 fold for permethrin; 2.35–8.77 and 3.37–21.31 fold for spinosad, respectively. Considering the overall results, spinosad proved to be the most toxic insecticide to the laboratory and field strains of T. granarium when compared with toxicity of pirimiphos-methyl or permethrin. Insecticidal bioassays implementing enzyme inhibitors revealed no effect on synergizing the toxicity of all the insecticides in the Lab-TG strain; however, enzyme inhibitors significantly synergized toxicity of pirimiphos-methyl in all the field strain suggesting the major involvement of metabolic mechanism associated with pirimiphos-methyl resistance. The study demonstrates variation in susceptibility to insecticides in T. granarium strains. The results might be helpful for monitoring future variation in susceptibility to insecticides in T. granarium and for setting field rates. 相似文献
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Insecticidal effect of spinosad dust, in combination with diatomaceous earth, against two stored-grain beetle species 总被引:1,自引:1,他引:0
Laboratory bioassays were carried out to determine the efficacy of spinosad applied alone or combined with the diatomaceous earth (DE) SilicoSec against adult rice weevils, Sitophilus oryzae and confused flour beetles, Tribolium confusum. Efficacy was assessed on wheat and maize at three dosages of spinosad dust formulation (corresponding to 0.0625, 0.1875 and 0.625 ppm of active ingredient [AI] for S. oryzae and to 0.1875, 0.625 and 1.25 ppm of AI for T. confusum), alone or combined with SilicoSec at 150 ppm for S. oryzae and 250 ppm for T. confusum. The mortality of S. oryzae exposed for 14 d on wheat treated with spinosad ranged between 83% and 100%. Conversely, the mortality of S. oryzae on maize treated with DE or on maize treated with lower doses of spinosad dust did not exceed 19% and was only 59% on maize with the highest spinosad dust treatment. Generally, the presence of SilicoSec combined with spinosad did not significantly increase S. oryzae mortality compared with spinosad alone. For T. confusum, mortality on both commodities was lower than for S. oryzae. After 14 d of exposure on wheat, mortality was 14% at the highest dose of spinosad, but increased to 33% in the presence of DE. Similar results were also obtained for T. confusum exposed on treated maize, which indicated a joint action between spinosad and DE. In the case of S. oryzae, the inclusion of DE reduced progeny production in comparison with spinosad alone. Progeny production of T. confusum was relatively low in all treatments, compared to progeny production of S. oryzae. The results of the study show the potential of combination treatments of spinosad dust and DE, but efficacy varies with the target insect species and commodity. 相似文献
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Spinosad has recently been registered in several countries for long-term protection against a range of stored grain insects including the lesser grain borer, Rhyzopertha dominica (F.). The potential for development of resistance to spinosad is demonstrated by the existence of resistance in many insect pests of agriculture. The aim of this study was to determine the base-line susceptibility of R. dominica to spinosad, to provide a basis for future resistance monitoring. Eighteen insect populations of R. dominica were collected from field storage sites across four States within Australia, and exposed to a range of spinosad rates, including its current registered rate of 1 mg kg−1 (1 ppm). Base-line susceptibility was assessed based on adult mortality and production of F1 adults. Comparison of LC50 and LC99.9 indicated the existence of low level of variation among the tested R. dominica populations, in their susceptibility to spinosad. For adults, there was a narrow range of LC50 values with the highest (0.027 ppm) being 2.5 × the lowest (0.011 mg kg−1). Similarly, LC99.9 values showed a narrow range with the highest (0.36 mg kg−1) being 3.6 × the lowest (0.10 mg kg−1). For adult progeny produced in spinosad treated grain, there was a narrow range of LC50 values with the highest (0.025 mg kg−1) being 5 × the lowest (0.004 mg kg−1) and the highest LC99.9 values (0.67 mg kg−1) being 5 × the lowest LC99.9 (0.13 mg kg−1). Based on the data generated from this study, we recommend a dose of 1 mg kg−1(1 ppm) to be used to discriminate between susceptible and resistant populations for future resistance monitoring programs. 相似文献
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The granary and maize weevils are serious worldwide threats to stored products and their control has heavily relied on synthetic insecticides, which are largely recommended based on studies with acute lethal doses neglecting the importance of potential sublethal effects of insecticides. Deltamethrin has been widely used for managing grain weevils and other stored grain pest species, but reported control failures with this insecticide sparked the search for alternative insecticidal compounds. The bioinsecticide spinosad is one of such alternatives whose use against stored grain insect pests is relatively recent, but encompasses the control of grain weevils. Nonetheless, little is known about the sublethal effects of spinosad on these insect pest species. Here we assessed the insecticidal effects of commercial formulations of spinosad and deltamethrin against the weevil species Sitophilus granarius and S. zeamais. Both spinosad and deltamethrin were able to effectively control the insects, although the latter caused a faster mortality than the former. Behavioral pattern changes were caused by both insecticides, especially deltamethrin, triggering irritability (i.e., avoidance after contact). Different feeding and drinking responses were also detected for both weevil species, which exhibited significant avoidance to deltamethrin and to spinosad, but with a milder response to the latter. Apparently spinosad is not as easily recognizable as deltamethrin by S. zeamais and S. granarius, remaining effective against both species without minimizing as much the potential exposure as deltamethrin. 相似文献
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Manoj K. Nayak Gregory J. Daglish Valerie S. Byrne 《Journal of Stored Products Research》2005,41(4):455-467
Effectiveness of the bacterium-derived insecticide, spinosad, was determined against eight storage pests of Australia. Laboratory experiments were carried out on relevant resistant strains of four beetle and four psocid species, with the aim of determining the potential of spinosad as a new grain protectant. To explore the possibility that spinosad could have delayed effects, we exposed all insects for 14 d initially and then a further 14 and 28 d for psocids and beetles, respectively. Adult insects of each strain were exposed to untreated wheat (control) and wheat treated with spinosad at 0.1, 0.5 and 1 mg [a.i.]/kg of grain, and adult mortality and reduction of progeny were determined. Among beetles, spinosad was most effective against Rhyzopertha dominica (F.), with 100% adult mortality and progeny reduction after 14 d exposure at 1 mg [a.i.]/kg. Efficacy of spinosad was less with Sitophilus oryzae (L.), and least with Tribolium castaneum (Herbst) and Oryzaephilus surinamensis (L.). Against the psocids, spinosad was most effective against Liposcelis entomophila (Enderlein), with 100% adult mortality after 28 d exposure at 1 mg [a.i.]/kg and 92% progeny reduction after 14 d exposure and 100% subsequently. Spinosad was only moderately effective against Liposcelis bostrychophila Badonnel, L. decolor (Pearman) and L. paeta Pearman. Our findings suggest spinosad to be a potential protectant against R. dominica and L. entomophila in stored grain in Australia. This potential use would be in combination with another protectant capable of controlling other members of the pest complex. 相似文献
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多杀菌素是一种安全、高效的新型生物杀虫剂。对多杀菌素的来源、结构、作用机理、在储粮害虫防治中的研究及应用、残留检测等进行综述,以期为多杀菌素的深入研究和推广应用提供参考,并促进多杀菌素在我国储粮害虫防治领域的研究和应用。 相似文献
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The bacterial formulations, spinosad and spinetoram, were evaluated for their efficacy in suppressing development and mating success in Cadra cautella (Walk.) (Lepidoptera: Pyralidae), the almond moth. A dilution series of spinosad and spinetoram was sprayed on rice flour. Rice flour samples sprayed with water served as the control. Late instar C. cautella larvae were introduced onto spinosad-, spinetoram-, or water-treated rice flour. The first experiment tested the effects of spinosad and spinetoram on larval mortality, as well as emergence of adults and progeny at different insecticide concentrations. In the second experiment, the mating success of C. cautella adults that had emerged from larvae exposed to spinosad was tested inside a cubicle. Both spinosad and spinetoram increased larval mortality, whereas both compounds reduced adult emergence and progeny production. Natural mating was reduced in the presence of the synthetic sex pheromone (Z,E)-9,12-tetradecadienyl acetate. However, exposure of C. cautella larvae to spinosad did not alter mating in adult progeny. Spinosad was more effective than spinetoram at suppressing C. cautella development. The study concludes that both spinosad and spinetoram suppress the development of immatures of C. cautella to the adult stage as well as mating. Thus, the both compounds can be used to protect stored grains from infestation by C. cautella. 相似文献
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Sitophilus oryzae and Rhyzopertha dominica are serious insect pests of stored products in Sri Lanka. Currently pirimiphos methyl and phosphine fumigation are used as control measures but grain handlers seek for alternatives. Exposure to high or low temperature is popular in stored-product insect pest management but is expensive. Spinosad is effective against certain stored-product insects but has not yet been tested for its synergy with heat or cold. This experiment was conducted to evaluate the effect of spinosad on the heat tolerance and cold tolerance of S. oryzae and R. dominica adults. The experiment was a two-factor factorial, complete randomized design with four replicates. The spinosad concentration and exposure period were changed. Adults of S. oryzae and R. dominica were first exposed to a series of spinosad concentrations. Later they were held at higher (40 °C) or lower (6–11 °C) temperatures than room temperature for different durations.Pre exposure of S. oryzae adults to Spinosad at 18 ppm or above synergized the adult mortality at high or low temperature showing a dose response. Pre-exposure of R. dominica adults to spinosad concentrations 12.5 ppm or higher synergized the mortality at high temperature whereas the spinosad synergized the mortality of R. dominica at low temperature when exposed to 6.25 ppm or higher concentrations; the effects followed a dose response. This study shows that heat and cold tolerance of S. oryzae and R. dominica adults are reduced by pre-exposure to spinosad. Therefore, spinosad is a potential grain protectant at high or low temperatures against these two insect species. 相似文献
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通过2种途径向菌株ASAGF W2引入链霉素、庆大霉素、利福平和氯霉素抗性,研究抗生素抗性筛选技术对选育多杀菌素高产菌株的作用效果。途径一是将4种抗生素的抗性通过含有抗生素的平板逐级引入,标记为非GYM组;途径二是将分离得到的抗性突变菌进行纯培养后通过抗生素平板引入下一种抗性,标记为GYM组,利用摇瓶发酵进行多杀菌素高产菌株的选育。结果显示非GYM组的方法是进行抗生素抗性筛选的较适途径;通过对高产菌株连续转接5次,最终获得4株遗传稳定的高产突变菌,其中突变菌13-8-1来自非GYM组,具有Str~(0.5)Gen~(10)双重抗性,多杀菌素平均发酵产量较出发菌株ASAGF W2提高了23.87%。利用抗生素抗性筛选技术选育多杀菌素高产菌株,简单易行且效果显著。 相似文献