菌种冷冻干燥保藏的影响因素

菌种资源保藏是微生物学及相关学科研究的基础.冷冻干燥保藏法是菌种保藏最有效的方法之一,为进一步提高菌种保藏质量人们进行了大量的研究.本文介绍了菌种冷冻干燥保藏方法的原理和优点,同时详细介绍了菌种冷冻干燥保藏方法的影响因素.     

8种不同方法保藏病原菌效果的对比观察

采用８种不同的菌种保藏方法,对１８种常见病原菌的保藏时间及生物学特性的影响进行了对比观察。结果表明：冷冻干燥法保藏菌种时间最长（本实验室已保存１５年）;肉浸汤琼脂平板法保藏菌种时间最短（２～３月）。保藏时间由长到短依次为：冷冻干燥法＞半固体冷冻法≥半固体斜面加液体石蜡覆盖法＞半固体斜面法＞肉浸汤加液体石蜡覆盖法＞血琼脂平板法＞肉浸汤法＞肉浸汤琼脂平板法。且相同方法对不同菌种保藏时间不同。保藏时间在１年以内的菌种,其生物学特性无明显变异;而经冷冻干燥法保藏时间较长的白喉棒状杆菌、金黄色葡萄球菌、甲型副伤寒沙     

微生物冷冻干燥的抗性机理

微生物冷冻干燥的抗性机理陈声明,吕琴（浙江农业大学环保系,杭州３１００２９）微生物冷冻干燥法是长期保藏菌种的较好方法之一。因其便于批量生产、长期保藏成活力高,保藏和运输设备简单而成为一种普遍使用的保藏方法,已广泛应用于保存大部分细菌、真菌和一些病毒。...     

医学真菌菌株保藏方法概述

近年来,随着真菌感染的患者急剧增加,真菌病已经成为一个重要的公共卫生问题。对医学真菌流行病学、致病机理、耐药机理以及防治策略的研究尤为重要,而所有研究的基础都建立在对医学真菌的进行有效的保藏。医学真菌的保藏方法很多,包括传代法、蒸馏水法、冷冻干燥保藏法等,保藏方法的选择因实验室条件、菌种和研究要求不同而不同。本文对目前常用的几种医学真菌菌种保藏方法的优缺点及其应用等做了综述。     

介绍一种保藏菌种的简易方法

保藏菌种以真空冷冻干燥法最佳。但基层限于设备条件,常采用半固体覆盖液体石蜡4℃保藏,该法除必须定期转种外,菌株还容易发生变异。从1982年11月以来,我们采用简易干燥法保藏菌种,经几年观察,效果良好。现介绍于下:     

沼气高产菌群保藏条件的比较

目的：利用不同方法对沼气高产菌群进行保藏,比较各方法不同时间的保藏效果。方法：应用液体低温冷藏法、液体石蜡封存法、液氮冷冻保藏法和低温冷冻干燥保藏法保藏的菌种,分别在保藏后1个月、3个月、6个月及1年后复苏菌种,测定其产气速度、产气量。结果：以上几种方法均能够保证所保藏菌群在1个月内得到复苏并产气,低温冷冻干燥法及液氮冷冻法保藏沼气产生菌菌群可达1年以上,产气速度、产气量较为理想,优于液体低温冷藏法及液体石蜡法。     

乳酸菌冻干保藏相关影响因素的研究进展

乳酸菌在冻干保藏过程中受到多种因素的作用,采取适宜的保护措施,在很大程度上可避免或减轻冷冻干燥对细胞带来的损伤.主要介绍了影响乳酸菌冷冻干燥及保藏相关因素的研究进展,这些因素包括:菌种自身的性质、生长因素、亚致死处理、冻干保护介质和复水条件.     

用三种不同方法保藏短小芽孢杆菌的比较研究

据前人研究,不同微生物应采取不同的方法进行保藏。我们利用短小芽孢杆菌产生碱性蛋白酶的特点,以其酶活性变化为指标比较了冷冻干燥法、沙土法及定期移植法三种不同方法的优劣,考查不同保藏方法对微生物生理活性的影响,为微生物的菌种保藏工作提供依据。     

冻干菌种复活、保藏方法探讨

药品检验用的标准菌株主要来自中国药品生物制品检定所医学菌种保藏中心(China Medial Culture Collection,CMCC),由这个中心提供的冷冻干燥菌种处于休眠状态,活性低,需经过复活才可作为工作用菌。我们在工作中体会到,只有做好菌种的复活、保藏才能保持菌种的生物学特征,保证菌     

几种真姬菇菌种保藏方法的保藏效果对比

【背景】菌种保藏方法与保藏效果是菌种质量的前提和保证。随着真姬菇Hypsizygus marmoreus栽培规模和产量的逐年递增,选择最佳的菌种保藏方法也越来越迫切。【目的】对真姬菇菌种的常见保藏方法及保藏效果进行分析和研究,寻找简便、高效、廉价的真姬菇菌种保藏方法。【方法】通过对比菌丝生长率、菌丝脱氢酶活性以及菌丝对色度培养基的脱色率等指标参数来评价保藏方法的保藏效果。【结果】通过对三大类27种真姬菇菌种保藏方法 3个月保藏效果的对比分析发现,三大类菌种保藏方法中保藏效果最好的是水溶液保藏法,其中以0.1%PEG6000水溶液保藏效果最佳;其次为木屑保藏法,其中以盐水浸泡过的杨木木屑保藏效果最好;斜面保藏法效果最差。正常保藏实验的效果好于加速保藏实验。【结论】与当前真姬菇菌种保藏的常规方法相对比,本实验所采用的菌种保藏方法大大拓宽了菌种保藏方法的种类与范围,提高了菌种保藏的效果。     

Key composition optimization of meat processed protein source by vacuum freeze-drying technology

Vacuum freeze-drying technology is a high technology content, a wide range of knowledge of technology in the field of drying technology is involved, it is also a method of the most complex drying equipment, the largest energy consumption, the highest cost of drying method, but due to the particularity of its dry goods: the freeze-drying food has the advantages of complex water performance is good, cooler and luster of freezing and drying food to maintain good products, less nutrient loss, light weight, easy to carry transportation, easy to long-term preservation, and on the quality is far superior to the obvious advantages of other dried food, making it become the forefront of drying technology research and development. The freeze-drying process of Chinese style ham and western Germany fruit tree tenderloin is studied in this paper, their eutectic point, melting point and collapse temperature, freeze-drying curve and its heat and mass transfer characteristics are got, then the precool temperature and the highest limiting temperature of sublimation interface are determined. The effect of system pressure on freeze-dried rate in freeze-drying process is discussed, and the method of regulating pressure circularly is determined.     

Drying of Epicoccum nigrum conidia for obtaining a shelf-stable biological product against brown rot disease

AIMS: The effects of freeze-drying, spray-drying and fluidized bed-drying on survival of Epicoccum nigrum conidia were compared. METHODS AND RESULTS: Viability of E. nigrum conidia (estimated by measuring its germination) was 100% after fluidized bed-drying and freeze-drying, but it was determined that skimmed milk must be added in the case of freeze-drying conidia. Addition of other protectants (Tween-20, peptone, sucrose, glucose, starch and peptone + starch) to skimmed milk before freeze-drying did not improve the conidial viability which was obtained with skimmed milk alone. Glycerol had a negative effect on the lyophilization of E. nigrum conidia. Epicoccum nigrum conidia freeze-dried with skimmed milk, or fluidized bed-dried alone maintained an initial viability for 30 and 90 days, respectively, for storage at room temperature. Epicoccum nigrum conidial viability after spray-drying was lower than 10%. CONCLUSIONS: The best method to dry E. nigrum conidia was fluidized bed-drying. Conidia without protectants dried by this method had 100% viability and survived for 90 days at room temperature. SIGNIFICANCE AND IMPACT OF STUDY: This paper deals with methods for the potential formulation of a biocontrol agent which is being tested for eventual commercialization.     

海藻糖载入红细胞及其冷冻干燥的实验研究

冷冻干燥保存是长期保存人体红细胞的理想方案之一。冻干保护剂海藻糖渗入细胞内后,对细胞膜和细胞内物质有保护作用,其中的一个作用是增加细胞质的浓度,使冻干过程容易形成稳定的玻璃态。应用高渗法处理红细胞,通过考察胞内海藻糖含量、红细胞冻干后的存活率、腺苷三磷酸酶(ATPase)、超氧化物歧化酶(SOD)活力以及细胞形态变化,研究胞内海藻糖含量对红细胞冻干后活性的影响。结果显示:海藻糖对红细胞冻干具有明显的保护作用,随胞内海藻糖浓度升高,其保护性能逐渐增强;43.8mmol/L的胞内海藻糖浓度对红细胞保护最好,细胞存活率达到53.6%,形态保持良好,ATP和SOD活力均在正常的范围内。     

Effect of the freeze-drying process on the phenotypic diversity of Pseudomonas putida strains isolated from the interior of healthy roots of Sida hermaphrodita: Phenotype microarrays (PMs)

The objective of this study was to research the effect of the freeze-drying process on the metabolic changes of Pseudomonas putida strains (E41, E42, R85) isolated from the interior of Sida hermaphrodita roots with the use of the phenotypic microarrays (PM) technology.The proposed method of the freeze-drying process with inulin as component lycoprotectant demonstrated a high bacterial survival ratio (BSR) immediately after freeze-drying and storage after 12 months. While, after 360 days of freeze-drying BSR decreased to value of 74.38.Pseudomonas putida strains were assayed on microplates PM1-PM5, and PM9-PM13 testing 664 different substrates. However, no significant differences in the use of C substrates were observed either before or after the freeze drying process. An insignificant negative effect of the freeze-drying on the use of these substrates was observed. The utilization of N, P and S sources was low or showed no metabolic activity for most of the compounds after freeze-drying. The freeze-drying process increased the sensitivity of the bacteria to antibiotics and selected chemicals.In this study, the freeze-drying process decreased the metabolic activities of the tested strains and their resistance to antibiotics and chemicals.     

Successful long-term preservation of rat sperm by freeze-drying

Background

Freeze-drying sperm has been developed as a new preservation method where liquid nitrogen is no longer necessary. An advantage of freeze-drying sperm is that it can be stored at 4°C and transported at room temperature. Although the successful freeze-drying of sperm has been reported in a number of animals, the possibility of long-term preservation using this method has not yet been studied.

Methodology/Principal Findings

Offspring were obtained from oocytes fertilized with rat epididymal sperm freeze-dried using a solution containing 10 mM Tris and 1 mM EDTA adjusted to pH 8.0. Tolerance of testicular sperm to freeze-drying was increased by pre-treatment with diamide. Offspring with normal fertility were obtained from oocytes fertilized with freeze-dried epididymal sperm stored at 4°C for 5 years.

Conclusions and Significance

Sperm with –SS– cross-linking in the thiol-disulfide of their protamine were highly tolerant to freeze-drying, and the fertility of freeze-dried sperm was maintained for 5 years without deterioration. This is the first report to demonstrate the successful freeze-drying of sperm using a new and simple method for long-term preservation.     

Freeze-drying vegetative mycelium of Laccaria fraterna and its subsequent regeneration

Laccaria fraterna, a basidiomycetous, filamentous, non-sporulating (in vitro) fungus, was subjected to freeze-drying and tested for viability after rehydration. The optimization of the freeze-drying protocol included selection of the candidate fungus; optimizing physiological growth conditions and age; standardizing the protectant type and concentration; optimizing the pre-freezing method, freeze-drying run and extent of drying; choice of the rehydrant and the extent of rehydration. The culture retained its viability after lyophilization and when subjected to quality assurance tests gave consistent results similar to the non-lyophilized culture, indicating the stability of the product and the applicability of the developed process to freeze-dry vegetative mycelium of filamentous non-sporulating fungi.     

Optimisation of initial cell concentration enhances freeze-drying tolerance of Pseudomonas chlororaphis

The freeze-drying tolerance of Pseudomonas chlororaphis, an antifungal bacterium used as biocontrol agent was investigated. P. chlororaphis is freeze-drying sensitive and the viability drops more than 3 log units in the absence of protective freeze-drying medium. Of the freeze-drying media tested, lactose, sucrose, trehalose, glutamate, sucrose with glutamate, skimmed milk, and skimmed milk with trehalose, skimmed milk gave the lowest survival (0.6+/-0.2%) and sucrose the highest (6.4+/-1.2%). Cellular accumulation of sucrose from the freeze-drying medium and the protective effect of sucrose were dependent on sucrose concentration. The effect of initial cell concentration, from 1 x 10(7) to 5 x 10(10) CFU/ml, on survival after freeze-drying was studied for carbon starved cells with sucrose as freeze-drying medium. The highest freeze-drying survival values, 15-25%, were obtained for initial cell concentrations between 1 x 10(9) and 1 x 10(10) CFU/ml. For cell concentrations outside this window more than 10 times lower survival values were observed. P. chlororaphis was cultivated to induce stress response that could confer protection against freeze-drying inactivation. Carbon starvation and, to a lesser extent, heat treatment enhanced freeze-drying tolerance. By combining optimal cell concentration, optimal sucrose concentration and carbon starvation the survival after freeze-drying was 26+/-6%.     

A Simple Apparatus for the Freeze-Drying of Biological Specimens Preparatory to Scanning Electron Microscopy

In this paper an apparatus is described which facilitates the freeze-drying of specimens prior to their examination by scanning electron microscopy (SEM). The apparatus has been constructed following the principle of a Dewar flask. It enables the operator to keep his SEM specimens free from contamination until immediately prior to coating and examination in the microscope. Examples of a human dental plaque and of a pure colony of Bacterionema matruchotii as prepared by this method are illustrated.