Cryoprotectants: the essential antifreezes to protect life in the frozen state. CryoLetters

University Department of Surgery, Royal Free and University College Medical School, London NW3 2QG, UK.
Cryo letters (Impact Factor: 1.14). 11/2004; 25(6):375-88.
Source: PubMed

ABSTRACT In the fifty years since the establishment of the cryoprotective effect of glycerol, cell banking by cryopreservation has become routine in many areas of biotechnology and medicine. Cryoprotectant addition has become a rather mundane step within the overall protocol. However, for future advances in cryobiology and to meet new challenges in the clinical use of cryopreserved cells or tissues, it will be essential to have an understanding of the development and current status of the biological and chemical knowledge on cryoprotectants (CPA). This review was undertaken to outline the history of CPA use, the important properties of CPA in relation to freezing damage, and what can be learnt from natural freezing-tolerant organisms. The conflicting effects of protection and toxicity resulting from use of CPA are discussed, and the role of CPA in enhancing glassy states in the emerging field of vitrification are also set out.

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Available from: Barry J Fuller, Sep 26, 2015
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    • "This suggests EY also has a contraceptive effect in the hen genital tract [29]. Unfortunately, the true mechanisms underlying the contraceptive effects of both GLY and EY remain unknown [1] [29]. The sperm–egg penetration (SP-holes) assay, however , could be useful in investigating them. "
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    ABSTRACT: Glycerol (GLY) and egg yolk (EY) are good cryoprotectants of avian and mammalian sperm, but in birds, they strongly inhibit the eventual fertilization of ova. Using the sperm penetration (SP-holes) assay and fertility trials, the present study investigates (1) the possible mechanism by which this contraceptive effect occurs in chickens and (2) the maximum concentrations of GLY and EY tolerated by fresh rooster sperm. Seventy Black-Barred Andaluza hens (five per treatment) were inseminated four times (twice per week) with 0.1 mL of fresh semen from roosters of the same breed diluted 1:1 (v:v) with Lake and Ravie medium containing different concentrations of GLY or EY. No adverse effects on acrosome integrity, sperm motility, or viability were seen with any concentration of GLY or EY. The number of SP-holes on perivitelline layer samples taken from above the germinal disc became progressively lower at GLY concentrations of 1.5% or greater (P > 0.05). No holes caused by sperms were seen in unfertilized eggs. The corresponding fertility results showed similar reductions when the GLY concentration was 1.5% or greater. No changes in the number of SP-holes were seen with increasing EY concentrations (0%-7.5%), nor were any differences in fertility observed, except for a reduction when 15% EY was used. The results therefore reveal that GLY affects the transit of sperms through the oviduct in their attempt to reach the infundibulum area, limiting their access to the ovum perivitelline layer. Egg yolk had no such effect, nor did it influence acrosome reaction capacity; its mechanism of contraceptive action therefore remains unknown. The maximum GLY and EY concentrations tolerated by the rooster sperm were 0.75% and 7.5%, respectively. Copyright © 2015 Elsevier Inc. All rights reserved.
    Theriogenology 02/2015; 83(9). DOI:10.1016/j.theriogenology.2015.02.002 · 1.80 Impact Factor
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    • "This might result from a competition for nitrite with AnAOB that have the best activity recovery when DMSO+TT was used as a CPA. The increased activity recovery of AnAOB could result from the effect of DMSO on the phospholipid bilayer [72] of intracytoplasmatic membranes which contain the key enzymes for ammonium oxidation [19]. Besides the autotrophic functional community members, filamentous bacteria from the phylum Bacteriodetes and bacteria belonging to the phylum Actinobacteria were described [69] in the OLAND biomass. "
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    ABSTRACT: The use of mixed microbial communities (microbiomes) for biotechnological applications has steadily increased over the past decades. However, these microbiomes are not readily available from public culture collections, hampering their potential for widespread use. The main reason for this lack of availability is the lack of an effective cryopreservation protocol. Due to this critical need, we evaluated the functionality as well as the community structure of three different types of microbiomes before and after cryopreservation with two cryoprotective agents (CPA). Microbiomes were selected based upon relevance towards applications: (1) a methanotrophic co-culture (MOB), with potential for mitigation of greenhouse gas emissions, environmental pollutants removal and bioplastics production; (2) an oxygen limited autotrophic nitrification/denitrification (OLAND) biofilm, with enhanced economic and ecological benefits for wastewater treatment, and (3) fecal material from a human donor, with potential applications for fecal transplants and pre/probiotics research. After three months of cryopreservation at -80°C, we found that metabolic activity, in terms of the specific activity recovery of MOB, aerobic ammonium oxidizing bacteria (AerAOB) and anaerobic AOB (AnAOB, anammox) in the OLAND mixed culture, resumes sooner when one of our selected CPA [dimethyl sulfoxide (DMSO) and DMSO plus trehalose and tryptic soy broth (DMSO+TT)] was added. However, the activity of the fecal community was not influenced by the CPA addition, although the preservation of the community structure (as determined by 16S rRNA gene sequencing) was enhanced by addition of CPA. In summary, we have evaluated a cryopreservation protocol that succeeded in preserving both community structure and functionality of value-added microbiomes. This will allow individual laboratories and culture collections to boost the use of microbiomes in biotechnological applications.
    PLoS ONE 06/2014; 9(6):e99517. DOI:10.1371/journal.pone.0099517 · 3.23 Impact Factor
    • "Owing to their physical protective properties many commonly employed cryoprotectants also impart additional defenses against cryoinjury (Fuller, 2004; Benson and Bremner, 2004) as they can stabilize proteins and membranes and in some cases act as antioxidants. "
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    ABSTRACT: Survival at low temperatures is a widespread phenomenon in nature and can be observed across a wide range of organisms including cyanobacteria. Low temperature slows metabolism and under appropriate conditions enhances longevity, conferring stability on living cells. Successful storage of cyanobacterial strains in cryobanks is dependent upon the use of effective cryoprotective strategies, and understanding the basic principles of cryobiology is fundamental in their development. Cryopreservation of cyanobacteria is usually undertaken by controlled-rate cooling coupled with colligative cryoprotection, but vitrification has also been successfully employed. With some exceptions, cryopreserved “collections” are housed in one of the major service-based biological resource centres (BRCs), such as the American Type Culture Collection. BRCs maintain practices, including the application of optimal cryopreservation protocols, to ensure that the samples of organisms they hold and distribute sustain these important attributes.
    Cyanobacteria, 11/2013: pages 319-327; , ISBN: 9781119941279
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