烟田中静电喷雾和电动喷雾下噻虫嗪的防效及对昆虫群落的影响

【目的】探明静电喷雾与电动喷雾对噻虫嗪防治害虫效果及烟田昆虫群落的影响,为静电喷雾在烟草上的推广应用提供理论依据。【方法】利用静电喷雾与电动喷雾法喷施0.66 g·L~(-1)25%噻虫嗪水分散粒剂,施药1、3、7 d后,测定2种方法对烟蚜与斜纹夜蛾的防治效果、在烟株与土壤中的沉积以及对昆虫群落的影响。【结果】喷施25%噻虫嗪水分散粒剂1、3、7 d后,静电喷雾对烟蚜和斜纹夜蛾的防治效果均显著高于电动喷雾的防治效果,且防治效果均随时间的推移而升高。噻虫嗪在静电喷雾处理区烟叶上的沉积量高于电动喷雾处理区烟叶上的沉积量,而在静电喷雾处理区土壤中的沉积量低于电动喷雾处理区土壤中的沉积量,且都随时间的推移而降低。静电喷雾与电动喷雾均引起烟田昆虫群落的变化,静电喷雾引起的害虫和中性昆虫的数量变化大于电动喷雾,但天敌昆虫的数量变化小于电动喷雾,且静电喷雾区烟田的物种丰富度明显高于电动喷雾区,可见静电喷雾施药对烟田昆虫群落的影响小于电动喷雾施药。静电喷雾的S_t/S_i与S_n/S_p比值明显高于电动喷雾,说明静电喷雾烟田中昆虫群落稳定性高于电动喷雾烟田中昆虫群落的稳定性。【结论】相比电动喷雾,静电喷雾能够提高噻虫嗪在烟叶上的沉积量,从而提高噻虫嗪对害虫的防治效果,同时减少噻虫嗪在土壤中的沉积量,提高噻虫嗪的生态安全性,因此,静电喷雾在烟草病虫害防治上具有较好的应用前景。     

灵芝孢子油微胶囊制备技术

灵芝孢子油是从灵芝孢子粉中提取的具有一定药理活性的脂质成分。为提高灵芝孢子油稳定性,以大豆分离蛋白和麦芽糊精为壁材,采用喷雾干燥法和冷冻干燥法制备灵芝孢子油微胶囊。通过试验优化了制备工艺条件并比较了两者干燥方式制备微胶囊的理化性质。结果表明：最佳工艺为大豆分离蛋白和麦芽糊精质量比1:1、固形物含量20%、均质压力30MPa、壁材芯材质量比4:1。两种干燥方式微胶囊流动性、溶解性均较好,差异不显著。但两种微胶囊形态差异较大,喷雾干燥微胶囊整体呈球状、表面紧密无裂缝有凹陷,包埋率为90.84%;冷冻干燥微胶囊结构疏松呈片状,表面多孔。因此喷雾干燥法更适合包埋灵芝孢子油。     

微胶囊化蒜粉的工艺研究

蒜粉微胶囊化工艺可以保护蒜粉中的生物活性物质不被破坏.本文研究了不同的工艺条件对微胶囊化蒜粉的产率和效率的影响.结果表明最佳工艺条件为:蒜粉粒径范围30～100目,EC壁材溶液浓度3%,心材与壁材比4∶ 1,壁材与聚乙二醇(PEG)比4∶ 1,此时微胶囊化产率和效率分别达到95%和96.8%.     

拟除虫菊酯微胶囊的制备

以海藻酸钠、壳聚糖为壁材,氯氟氰菊酯为芯材,通过复凝聚法制备微胶囊。用红外光谱确定复合膜的形成,光学显微镜观察微胶囊的分散性和规整度,气相色谱法测定包封率。考察油水相体积比、搅拌速度、乳液稀释水用量及壳聚糖的浓度对氯氟氰菊酯微胶囊化的影响。结果表明,最佳的实验条件是油水相体积比为1∶10、搅拌速度为1300 r/min、乳液与水体积比为1∶1.2,壳聚糖浓度为0.1%。制备的微胶囊包封率可以达到80.3%。     

用于白蚁防治的联苯菊酯微胶囊的制备及性能研究

针对白蚁防治药剂联苯菊酯传统加工剂型存在的安全性差、持效期短等缺点,采用溶剂蒸发法制备联苯菊酯微胶囊.通过粒径大小、外观形貌、包封率以及载药量筛选出最佳芯壁比、乳化剂用量和剪切时间,并对微胶囊理化特性及释放性能进行表征,同时考察微胶囊对白蚁的杀灭效果和持效性.研究结果表明,芯壁比为1:1.5,乳化剂用量为7％,剪切时间为6 min时制备的联苯菊酯微胶囊粒径适中(97.6μm),包封率高达70.5％,缓释性能良好,与市售乳油相比,对白蚁的杀灭效果相当,但持效性能优异.该研究获得的联苯菊酯微胶囊为安全、高效防治白蚁提供了技术手段.     

生姜精油喷雾干燥法微胶囊化的研究

本文研究了以阿拉伯胶、麦芽糊精及大豆分离蛋白作为包埋生姜精油的壁材,采用三因子单形重心法优化确定壁材的最佳配方及工艺条件,采用喷雾干燥技术进行生姜精油的微胶囊包埋处理以获得固化的生姜精油微胶囊产品。     

乳酸菌的安全性研究

乳酸菌通常被认为是安全的,但在机体免疫抑制、肠道发育未成熟、肠上皮受损等情况下,可以导致心内膜炎、菌血症、局部性感染等临床症状.本文综述了国外有关乳酸菌的致病性、抗药性基因转移方面研究的一些新进展,以期引起国内对乳酸菌安全性问题的重视.     

乳酸菌素对指示菌作用方式的研究

利用指示菌生长曲线法和琼脂再培养法研究了乳酸杆菌ＡＴ－１产生的乳酸菌素对指示菌（Ｅｓｃｈｅｒｉｃｈｉａｃｏｌｉ．ｓｐ．４４４７）的作用方式。与大多数抑菌剂的作用规律相似,乳酸菌素在极低浓度（＜２４ＷＵ：１０６个Ｅ．ｃｏｌｉｓｐ．４４４７）时,能刺激指示菌的生长;达到一定浓度之后,开始表现出抑菌作用,并且随其浓度逐渐增高（４０～８０ＷＵ：１０６个Ｅ．ｃｏｌｉｓｐ．４４４７）,抑菌作用更加显著直至完全抑制指示菌的生长。取检测平板上透明圈区域的琼脂块于肉汤液体培养基中３７℃再培养２４ｈ,指示菌仍能生长,该结果表明：由乳酸杆菌ＡＴ－１产生的乳酸菌素对指示菌的生长呈现抑制作用。     

Preservation of probiotic strains isolated from kefir by spray drying

Aims:  This work aims to investigate the survival of Lactobacillus kefir CIDCA 8348, Lactobacillus plantarum CIDCA 83114 and Saccharomyces lipolytica CIDCA 812, all isolated from kefir, during spray drying and subsequent storage.
Methods and Results:  Micro-organisms were grown in De Man, Rogosa, Sharpe (MRS) or yeast medium (YM) medium and harvested in the stationary phase of growth. The thermotolerance in skim milk ( D and Z values), the survival of spray drying at different outlet air temperatures and subsequent storage in different conditions during 150 days were studied. The resistance to the heat treatments was higher in Lact. plantarum compared to Lact. kefir and S. lipolytica . The three micro-organisms studied varied considerably in their ability to survive to spray drying processes . Lactobacillus plantarum showed the highest survival rate for all the tested outlet air temperatures and also to the further storage in the dried state. The survival rates of Lact. kefir and S. lipolytica through drying and subsequent storage in the dried state decreased when the drying outlet air temperatures increased.
Conclusions:  Spray drying is a suitable method to preserve micro-organisms isolated from kefir grains. A high proportion of cells were still viable after 80 days of storage at refrigerated temperatures
Significance and Impact of Study:  It is the first report about spray-dried probiotic strains isolated from kefir grain and contributes to the knowledge about these micro-organisms for their future application in novel dehydrated products.     

乳杆菌吸附苯并芘的特性

[目的]探讨植物乳杆菌(Lactobacillus plantarum)121和戊糖乳杆菌(Lactobacillus pentosus)ML32的苯并芘吸附作用与机制.[方法]采用高效液相色谱检测菌体对苯并芘的吸附率.[结果]菌株121和ML32对苯并芘的吸附率分别为65.9%和64.9%,这种吸附特性与菌体活力无关,随培养时间延长、温度提高以及细胞浓度的上升而增加.菌株121和ML32的吸附率在pH 4和5时达到最大,分别为87.6%和89.0%.当培养液中Ca2+或Mg2+浓度大于0.05mol/L时,菌体吸附率与盐离子浓度呈正相关.苯洗脱会导致乳杆菌所吸附的苯并芘减少90%.经碱性蛋白酶、中性蛋白酶、溶菌酶及TCA和SDS等方法处理后,菌体吸附率上升,且不易被苯去除.在胆盐及胃酸环境下,两株菌的吸附率均提高至70%以上,而胰蛋白酶的存在仅对菌株121的吸附率有较大影响.[结论]两株乳杆菌可以通过吸附作用从环境中清除苯并芘,其吸附效果与细菌细胞壁的结构和组成有关.     

Electrostatic interactions in proteins: Calculations of the electrostatic term of free energy and the electrostatic potential field

The pH-dependence of the electrostatic energy of interactions between titratable groups is calculated for some well studied globular proteins: basic pancreatic trypsin inhibitor, sperm whale myoglobin and tuna cytochrome c. The calculations are carried out using a semi-empirical appraach in terms of the macroscopic model based on the Kirkwood-Tanford theory. The results are discussed in the light of their physicochemical and biological properties. It was found that the pH-dependence of the electrostatic energy correlates with the III–IV transition of cytochrome c. The electrostatic field of the cysteine proteinase inhibitor, cystatin, was calculated in two ways. In the first one, the electrostatic field created by the pH dependent charges of the ionizable groups and peptide dipoles was calculated using the approach proposed. In the second one, the finite-difference method was used. The results obtained by the two methods are in overall agreement. The calculated field was discussed in terms of the binding of cystatin to papain.     

Effect of electrostatic spray parameters on the viability of two bacterial biocontrol agents and their deposition on blueberry flower stigmas

The fungus Monilinia vaccinii-corymbosi infects blueberry flowers via the stigma-style ovary pathway to cause mummy berry disease. Previous laboratory experiments documented considerable activity of stigma-applied biofungicides containing the bacteria Bacillus subtilis and, to a lesser extent, Pseudomonas fluorescens against flower infection by the pathogen. However, adequate and targeted delivery of the biocontrol agents to the stigmatic surfaces of open flowers in the field has remained problematic. Here we consider the application of the biofungicides Serenade AS (containing B. subtilis QST713) and BlightBan A506 (containing P. fluorescens A506) to blueberry flowers by air-assisted electrostatic spraying. In laboratory experiments with typical field-use rates, viability of B. subtilis and P. fluorescens was unaffected by different levels of induction-charging voltage (0–1.2 kV) and atomizing pressure (138–276 kPa) applied to an electrostatic spray-charging nozzle, showing that the bacteria in both formulations readily survived exposure to the intense electrical fields and near-sonic atomizing air shear encountered during electrostatic spraying. Electrostatically charged application significantly (P<0.0001) increased deposition of B. subtilis on the stigmatic surfaces of detached blueberry flower clusters by a factor of 4.5 compared with conventional hydraulic spraying; a similar comparison showed that population densities of P. fluorescens on the stigma were increased by a factor of 2.9, but this effect was not statistically significant (P=0.1487). For Serenade, the increased coverage and/or retention on the flower stigma, along with the excellent bacterial survival, portend well for electrostatic application for mummy berry disease control in the field.     

人胃粘膜乳酸杆菌与幽门螺杆菌感染的相关性

目的:探讨胃内正常菌群乳酸杆菌对幽门螺杆菌(Helicobacter pylori,HP)的影响。方法:51例胃粘膜活检标本均取自于行胃镜检查的胃炎患者,分离培养乳酸杆菌,通过扩增其16S rRNA基因并测序来鉴定乳酸杆菌的种类;胃炎程度及活动度的分类依据悉尼分类系统,运用改良Gimesa染色鉴定HP感染。结果:胃粘膜中共分离出9种乳酸杆菌,分离阳性率为49.0%;乳酸杆菌阳性病人与阴性病人的HP感染率、胃炎程度的差异及胃炎活动度的差异均无统计学意义(P>0.05);HP阳性病人的胃炎程度较HP阴性病人更严重(P<0.05);有益生菌作用的乳酸杆菌与非益生菌类乳酸杆菌的HP感染率差异无统计学意义(P>0.05)。结论:胃内乳酸杆菌的存在对HP感染无影响。     

The electrostatic field of the component units of DNA and its relationship to hydration

The electrostatic fields of the subunits of DNA are presented and compared with the corresponding electrostatic potentials. Differences are observed between these two properties, due to their different dependence on distance, which are of considerable interest since, whereas the potential may be used in studying the reactivity of molecules towards charged species the field can be a similar guide to attack by neutral dipolar molecules such as water. It is demonstrated, for the example of the purine and pyrimidine bases that the field may indeed be used to detect preferential hydration sites.     

Control of redox properties of cytochrome c by special electrostatic interactions

An assessment is made of the proposal: electrostatic interactions between the ferric ion of oxidised cytochrome c and its haem propionate sidechains assists in determining the value of the redox potential and plays an important role in the redox state conformation change. Differences between the properties of homologous cytochromes are proposed to be due to differences associated with the charge on their haem propionates.     

Investigating the dielectric effects of channel pore water on the electrostatic barriers of the permeation ion by the finite difference Poisson-Boltzmann method

In this paper, the finite difference Poisson-Boltzmann (FDPB) method with four dielectric constants is developed to study the effect of dielectric saturation on the electrostatic barriers of the permeation ion. In this method, the inner shape of the channel pore is explicitly represented, and the fact that the dielectric constant inside the channel pore is different from that of bulk water is taken into account. A model channel system which is a right-handed twist bundle with four α-helical segments is provided for this study. From the FDPB calculations, it is found that the difference of the ionic electrostatic solvation energy for wider domains depends strongly on the pore radius in the vicinity of the ion when the pore dielectric constant is changed from 78 to 5. However, the electrostatic solvation energy of the permeation ion can not be significantly affected by the dielectric constant in regions with small pore radii. Our results indicate that the local electrostatic interactions inside the ion channel are of major importance for ion electrostatic solvation energies, and the effect of dielectric saturation on the electrostatic barriers is coupled to the interior channel dimensions. Received: 28 January 1997 / Accepted: 24 September 1997