果蝇胚胎石蜡切片制作方法的改良

探索一种不用在卵壳上手工打孔、适用于果蝇胚胎石蜡切片制作的方法。实验前期对果蝇胚胎进行渗透化处理,后期用琼脂糖、明胶、石蜡3种包埋辅佐剂对胚胎进行聚集、包埋、切片,最后进行HE及PASM染色。渗透化处理后的胚胎用琼脂糖或石蜡聚集并包埋后所制切片HE染色均显示胚胎形态结构正常,背景干净,而琼脂糖聚集法所制切片PASM染色背景呈灰色,明胶聚集法所制切片HE染色和PASM染色背景均显杂色且胚胎出现形变。3种包埋辅佐剂中,琼脂糖和石蜡均适于果蝇胚胎结构的保存,石蜡聚集法所制切片2种染色背景均无杂色,因此最适合做包埋辅佐剂。渗透化处理和石蜡聚集法结合后的改良方法适合于大样本且高脂含量的果蝇胚胎石蜡切片的制备。     

不同干燥方法对林下参品质的影响

目的：通过研究林下参不同干燥方法的干燥过程和对林下参物理性质及其皂苷类成分的影响，为林下参提供适宜干燥方法。方法：采用热风干燥、微波干燥、真空冷冻干燥3种干燥方法，对林下参的干燥时间、外观性状、体积收缩率、主根和芦的直径和长度收缩率、表皮和粉末的色泽及内在成分（总皂苷和8种单体皂苷）含量等指标进行分析评价。结果：微波干燥耗时最短，其次为真空冷冻干燥和热风干燥；真空冷冻干燥对林下参的外形和粉末色泽影响小，并且与热风干燥林下参的外观性状和微波干燥林下参的粉末色泽区别明显；真空冷冻干燥林下参和微波干燥林下参的体积、主根长和直径、芦长的收缩率小于热风干燥林下参，具显著差异；真空冷冻干燥林下参的表皮色差增长率最小；总皂苷含量、人参单体皂苷含量加和值、人参二醇型皂苷和人参三醇型皂苷含量的均值大小顺序为真空冷冻干燥林下参>微波干燥林下参>热风干燥林下参。结论：真空冷冻干燥较好的保留了林下参的形态和色泽，且真空冷冻干燥林下参人参皂苷含量高，真空冷冻干燥林下参具高附加值，综合考虑，真空冷冻干燥可以作为生产高档商品林下参的干燥方法。     

微波真空干燥大蒜片数学模型边界条件

本文通过确定大蒜片微波真空干燥的临界水分含量,修正Cu i等提出的胡萝卜片微波真空干燥动力学模型,使其适用于大蒜片,并对大蒜片与胡萝卜片微波真空干燥的临界水分含量不同的机理进行了探讨。采用质构仪和扫描电子显微镜分别对新鲜大蒜片、新鲜胡萝卜片以及干燥至边界条件下的大蒜片、胡萝卜片的质构和超微结构进行了测定。确定了大蒜片微波真空干燥的临界水分含量为Xw=1,在干燥后期对此模型进行了修正,修正系数为k=10.924e-3.2394Xw(0相似文献   

基于顶空-气相色谱-离子迁移谱法研究干燥方式对小米椒挥发性风味物质的影响

本研究采用顶空-气相色谱-离子迁移谱(HS-GC-IMS)技术对经热风干燥、红外干燥、真空冷冻干燥和自然晾晒4种干燥方式处理的小米椒进行挥发性风味物质分析。结果表明:这4种干燥方式获得的小米椒中共鉴定出挥发性风味物质39种,其中酯类9种、醛类10种、醇类10种、呋喃类2种、吡嗪类3种、酮类3种、有机酸类2种;小米椒干燥后的主要风味物质为酯类、醛类和醇类化合物。主成分分析(PCA)和热图聚类结果表明:相比于真空冷冻干燥与自然晾晒,热风干燥与红外干燥的挥发性风味物质具有较高的相关性;而与热风干燥和红外干燥相比,真空冷冻干燥与自然晾晒间的差异较大;干燥过程中部分挥发性风味物质间具有较强的相关性,如酯类和醇类、醇类和醛类等,其通过化学反应可实现风味物质间的转化。干燥方式对挥发性风味物质种类影响较小,热风干燥、红外干燥、真空冷冻干燥、自然晾晒的小米椒挥发性风味物质种类分别为39、37、36、34种。然而,干燥方式对小米椒挥发性风味物质的含量有明显的影响。与真空冷冻干燥和自然晾晒相比,热风干燥和红外干燥处理的样品中酯类、呋喃类和吡嗪类物质含量较高,而在真空冷冻干燥和自然晾晒处理的样品中醛类物质含量高于热风干燥和红外干燥。总之,相比于其他干燥方式,热风干燥与红外干燥对丰富干制小米椒的风味具有积极的影响。本研究将为干制小米椒的加工及风味品质调控提供理论依据。     

红酵母固态发酵类胡萝卜素产物稳定性的研究

探讨了红酵母固态发酵类胡萝卜素产物的干燥及储存方法;比较了真空干燥和鼓风干燥2种方法对固态发酵产物稳定性的影响;考察了光照、空气、储藏温度对固态发酵产物稳定性的影响。结果表明:在相同温度下,真空干燥(5.67±0.58)h比鼓风干燥所需时间短(9.33±0.58)h、类胡萝卜素损失小,效果也较好;光照和空气对其储藏过程中色素稳定性影响很大,30 d后类胡萝卜素损失了53%;培养物烘干后用透明塑料袋真空避光储藏效果显著,6个月后类胡萝卜素只损失19%,不抽真空损失了46%;温度对培养产物中色素稳定性影响不显著;红酵母菌株固态发酵培养产物应选择真空避光室温储藏。     

金针菇不同萃取物对肿瘤细胞的影响

比较冷冻干燥、鼓风干燥两种不同干燥方式对金针菇挥发性成分的影响,对干燥后香味物质较丰富的鼓风干燥方式获得的金针菇样品进行不同极性溶剂萃取并进行抗氧化及体外抗肿瘤试验。结果表明：两种干燥方式得到的主要挥发性成分均为醇类和醛类,但鼓风干燥后的金针菇样品中两类物质含量明显高于真空冷冻干燥方式获得的。体外药理实验表明不同萃取物在抗氧化和抗肿瘤细胞中均表现出良好的活性。     

壶瓶枣干燥预处理及提取工艺对其多糖得率的影响

本文考察了不同的干燥预处理手段(烘箱干燥和真空冷冻干燥)及减压内部沸腾法中各因素(真空度、温度、液料比和提取时间等)对壶瓶枣多糖及蛋白质得率的影响。实验结果表明:干燥方式对原料枣粉的色差和多糖、蛋白质含量均有显著影响,对含水量无明显影响;真空冷冻干燥所得的枣粉色差小、多糖含量高、蛋白质含量低,综合考虑,选用真空冷冻干燥作为原料预处理手段;减压内部沸腾法最佳工艺参数为体系内温度60℃,液料比50∶1(mL∶g),提取时间30 min,此时外界温度为71℃,真空度为80 kPa,此条件下多糖及蛋白质得率分别为26.05 mg/g和2.14 mg/g;与传统热浸提相比,有效物质多糖得率提高了16.66%。     

真空冷冻干燥技术在食用菌加工中的应用研究

简析了食用菌冻干制品产业发展形势,概述了真空冷冻干燥技术原理及产品特点,阐述了应用真空冷冻干燥技术加工食用菌制品所需的主要设备、生产工艺流程及操作要点。探讨真空冷冻干燥过程中,各项工艺参数对食用菌干燥特性的影响。介绍食用菌冷冻干燥技术的优越性、技术壁垒及发展前景,旨在为采用真空冷冻干燥技术对食用菌进行干燥加工提供参考。     

害虫防治用玫烟色拟青霉分生孢子粉的干燥工艺优化*

用液—固两相法生产的玫烟色拟青霉Paecilomyces fumosoroseus Pfr116菌株的分生孢子粉,在高真空冷冻干燥、高真空室温抽干、35℃下烘干和低真空低热干燥条件下进行不同程序的干燥处理,以筛选适合该菌孢子粉生产的干燥工艺条件。结果表明,低真空(0.1 MPa)低热(30℃)抽干20~24 h的干燥方法最适合用于该菌孢子粉的干燥,既能保证含水量在9.0%以下,又能保证87%以上的活孢率和1130亿~1310亿/g的含孢量,而且操作简便,成本较低,可作为高纯度孢子粉生产的首选干燥工艺。高真空(15.86 Pa)条件下无论冻干还是室温抽干,虽然孢子粉的含水量(2.2%~8.7%)和含孢量(1270亿~1360亿/g)指标符合生产要求,但活孢率仅62%,说明该菌孢子不适合在高真空条件下干燥。在35℃下烘干24 h所获孢子粉含水量、24 h萌发率和含孢量分别为9.6%、82.8%和1200亿/g,该方法也可在生产中应用,但其活孢率显著低于(P<0.05)低真空低热抽干24 h的孢子粉。     

未经真空干燥处理的白芨多糖的溶液流变性

真空加热干燥处理可能使多糖分子失去结合水,因而影响多糖溶液的黏度。本实验考察了未经真空干燥处理的白芨多糖(BSG)的溶液流变性,并与经过干燥的白芨多糖样品的溶液性质相比较。两组溶液的黏度变化规律相近,干燥处理没有破坏BSG溶液的黏性。BSG溶液的表观黏度(η)随浓度增加而增大。BSG溶液η对pH值变化不敏感,并具有优良的耐盐稳定性。改变溶液pH值,或者加入电解质,BSG溶液的η没有明显变化。升高温度(T),溶液η降低,η与T的变化关系符合Arrhenius方程。     

N-butyl Methacrylate and Paraffin as an Embedding Medium for Light Microscopy

A method of tissue embedding using n-butyl methacrylate and paraffin is described. Following alcohol dehydration and infiltration with the methacrylate monomer, tissues are embedded in gelatin capsules in a mixture consisting of 3.5 g of paraffin for each 10 ml of methacrylate. Benzoyl peroxide (0.2 g for each 10 ml of monomer) is added as the catalyst and the methacrylate polymerized in a 50 C oven for 18-24 h. Following polymerization the block is trimmed and embedded in paraffin to provide a firm support during sectioning. A water trough attached to the microtome knife is essential to facilitate the handling of sections and ribbons. For serial sections a mixture of equal weights of beeswax and paraffin is used to make the sections adhere to each other. Usual staining procedures can be used since the embedding medium is readily soluble in xylene.     

N-Butyl methacrylate and paraffin as an embedding medium for light microscopy.

A method of tissue embedding using n-butyl methacrylate and paraffin is described. Following alcohol dehydration and infiltration with the methacrylate monomer, tissues are embedded in gelatin capsules in a mixture consisting of 3.5 g of paraffin for each 10 ml of methacrylate. Benzoyl peroxide (0.2 g for each 10 ml of monomer) is added as the catalyst and the methacrylate polymerized in a 50 C oven for 18--24 h. Following polymerization the block is trimmed and embedded in paraffin to provide a firm support during sectioning. A water trough attached to the microtome knife is essential to facilitate the handling of sections and ribbons. For serial sections a mixture of equal weights of beeswax and paraffin is used to make the sections adhere to each other. Usual staining procedures can be used since the embedding medium is readily soluble in xylene.     

Drying of Tribenuron,a Thermosensitive Biochemical

The extension of microwave use in the biochemical industry was explored by drying tribenuron, a thermosensitive biochemical, in a microwave oven and in a thermal vacuum oven. Tribenuron wet cakes, containing a mixture of solvents, methanol and water, were heated at 40 °C in both ovens. Nitrogen purge was used to prevent the decomposition of tribenuron from prolonged heating. Microwave heating dried tribenuron in twenty minutes while the vacuum oven heating required eighteen hours to dry the wet cakes. In addition, the tribenuron quality was maintained under microwave drying, but deteriorated in the thermal vacuum oven. Therefore, microwave technology is more effective in drying tribenuron than conventional vacuum ovens. The results of this study are important for the use of microwave drying on a large scale in biochemical companies.     

Protective Paraffin Infiltration of Soft Tissues in Insects to Facilitate Softening of Hard Exoskeletons

This technique can produce serial sections as thin as 5 μ from hard chitin-covered materials of insects or other arthropods. Procedures: Fix with alcoholic Bouin's fluid for 3 hr. Henceforth subject material to partial vacuum in each step to ensure a final proper embedding. Wash with 80% ethanol 2 or 3 times for 2 hr or until the picric acid is largely removed. Dehydrate to 90% ethanol and give 2 changes of n-butanol 2 hr each, and one of a 1:1 n-butanol-paraffin mixture in 56-57° oven for 12 hr. Finally, use 2 baths of pure paraffin, 3 hr each, to complete the infiltration. After the last bath, withdraw the specimen from the paraffin, and remove the superficial paraffin, first mechanically and then with a xylene bath for 4 min. Rinse first with n-butanol, and afterwards with absolute ethanol, 2 min each. The compound eyes are protected with a paraffin covering, the specimen is hydrated with a 1% aqueous solution of detergent for 1 hr and then washed with running tap water. The material is treated with a concentrated sulfuric-nitric mixture (H₂SO₄:HNO₃) for 4 hr to eliminate the exoskeleton. After this treatment, the specimen is washed with running tap water for 12 hr, dehydrated with acetone and then bathed in a 2% solution of celloidin in ethyl acetate to form a protective artificial cuticle. This coating is hardened with 2 quick baths of chloroform, the specimen reembedded in paraffin, and the block cast for sectioning.     

Modifications of Lebowich's Soap-Wax Technic

Lebowich's technic is outlined for simultaneous dehydration and infiltration of tissues by a medium composed of stearic acid, 56° C. paraffin, diethylene glycol, and monoethanolamine. The prices and places where these materials may be purchased are given.

Tissue for sectioning is placed in acetone, C.P., for 1 hour, then put directly into the soap-wax medium at 60° C. under reduced pressure, and finally embedded in new soap-wax.

Modifications include a simplification of the apparatus used by Lebowich. A preserving jar fitted with a rubber stopper serves as a vacuum chamber, and use of an aspirator accomplishes the reduction of pressure. With invertebrate embryos up to 1000 μ diameter no reduction of pressure is needed. Embryos are fixed, washed, placed in acetone, infiltrated in soap-wax, and embedded.

By this soap-wax method the alcohols, xylene, and overnight drying of affixed ribbons are eliminated. Tissue may be fixed, sectioned, stained, and permanently mounted within 6 to 8 hours.     

A Tissue Basket for Paraffin Infiltration

The processes of washing, dehydration and paraffin infiltration when large numbers of tissues must be individually identified are always laborious. Washing and dehydration can be carried out in individual glass vials with relative ease and fairly rapidly if gravity flow reagent bottles are used to fill the vials. The use of similar vials for paraffin infiltration is usually complicated by hardening of the paraffin if too many vials are removed from the oven at once, or by cooling of the oven itself if it is too frequently opened. The same criticism applies to the process of embedding tissues when large numbers of vials must be handled simultaneously.     

A Tissue Basket for Paraffin Infiltration

The processes of washing, dehydration and paraffin infiltration when large numbers of tissues must be individually identified are always laborious. Washing and dehydration can be carried out in individual glass vials with relative ease and fairly rapidly if gravity flow reagent bottles are used to fill the vials. The use of similar vials for paraffin infiltration is usually complicated by hardening of the paraffin if too many vials are removed from the oven at once, or by cooling of the oven itself if it is too frequently opened. The same criticism applies to the process of embedding tissues when large numbers of vials must be handled simultaneously.     

Staining and Coating Roller-Tube Tissue Cultures

Decanted roller-tube tissue cultures are fixed either by oven drying (60-63°C) for 3 hr or by methyl alcohol for 5 min and stained within the tube with Harris hematoxylin (diluted 1:1) and 4.4% alcoholic eosin. Oven drying before staining emphasizes cytoplasmic detail, whereas methyl alcohol produces distinct nuclear detail. After dehydrating and clearing by alcohols and xylene, 1.0 ml of Fisher's Permount is pipetted into the roller tube which is held at a 5-10 angle, rotated until the tissue sheet is covered, and placed in a paraffin oven at this angle for 16-20 hr. With a few exceptions, a majority of tubes showed no tissue drying and only minimal fading after 4-6 mo.     

Improvement of the butyl methacrylate-paraffin embedment

The excellent butyl methacrylate-paraffin method as an embedment for light microscopy has been technically improved. More uniform and reproducible polymerization has been obtained by using a vacuum oven to degas the polymerizing mixture and to replace the air with nitrogen at 650 Torr. The amount of benzoyl peroxide required must be determined for each batch of butyl methacrylate. A teflon lined, reusable metal mold and a method of one-step blocking of tissues in preparation for sectioning are also described.     

Improvement of the Butyl Methacrylate-Paraffin Embedment

The excellent butyl methacrylate-paraffin method as an embedment for light microscopy has been technically improved. More uniform and reproducible polymerization has been obtained by using a vacuum oven to degas the polymerizing mixture and to replace the air with nitrogen at 650 Torr. The amount of benzoyl peroxide required must be determined for each batch of butyl methacrylate. A teflon lined, reusable metal mold and a method of one-step blocking of tissues in preparation for sectioning are also described.