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CryoLetters is a bimonthly, international journal for low temperature science and technology |
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CryoLetters 42 (6), 309-320 (2021) PERSPECTIVE: William V. Holt1* and Pierre Comizzoli2 1 Academic Unit of Reproductive and Developmental Medicine, Department of Oncology & Metabolism, University of Sheffield, Sheffield S10 2SF, United Kingdom. Abstract The value of cryopreserved germplasm in agriculture, aquaculture and medicine was recognized in the mid-twentieth century following the discovery in the late 1940s of a method for recovering viable spermatozoa after freeze-thawing. Sir Alan Parkes (a founder of cryobiology as a discipline) remarked that “time and space has been abolished for cattle breeding”, a phrase that continues to summarise the potential value of the Genetic Resource Bank (GRB) concept for all species. The underlying principle behind these remarks was based on the recognition that spermatozoa could remain viable for many years, and still achieve pregnancies even long after the semen donor had died. Nowadays, live mammalian embryos, amphibian spermatozoa and cultured somatic cells can also be stored for future use in conservation breeding programmes, where the overarching aim is to mitigate the deleterious impacts of inbreeding on the fitness and survival of populations. Revolutionary advances in the cryobiology of coral spermatozoa, embryos and larvae are also helping to counter the damaging effects of climate change and toxic chemicals on coral reefs. In this article we review the ways in which GRBs can contribute to global conservation activities, noting that species-specific biological differences can limit the success of standard animal breeding technologies such as artificial insemination and embryo transfer. These limitations mean that there is still a need for the development of novel, and possibly species-specific, GRB technologies. Keywords: amphibians; cloning; corals; embryos; oocytes; spermatozoa; stem cells. Download the paper: GENOME RESOURCE BANKING FOR WILDLIFE CONSERVATION: PROMISES AND CAVEATS (PDF)
CryoLetters 42 (6), 321-325 (2021) POST THAW QUALITY AND VIABILITY OF VITRIFIED IMMATURE SHEEP OOCYTES USING DIFFERENT CRYOPROTECTANT CONCENTRATIONS Khursheed Ahmad Sofi1*, Beenish Qureshi1, Riaz Ahmad Shah2 and Mujeebur Rehman Fazili3 1 Div. Veterinary Clinical Complex, F.V.Sc and A.H, Shuhama, SKUAST-Kashmir, Srinagar, India Abstract BACKGROUND: The cryopreservation of oocytes through vitrification is quite successful but oocyte vitrification is still being standardized because of their structural and molecular sensitivity to the cooling and freezing processes. OBJECTIVE: To evaluate the effect of different cryoprotectant concentrations on post-thaw morphology and viability of immature oocytes in sheep. MATERIALS AND METHODS: Vitrification was achieved in three vitrification solutions comprised of different concentrations of the cryoprotectants ethylene glycol + DMSO, viz., (G1) 20%, (G2) 30%, (G3) 40% ethylene glycol + DMSO in equal ratio. Cryopreservation was in open pulled straws. Post vitrification evaluation was done after 1 week’s storage in liquid nitrogen based on morphological evaluation and viability using trypan blue dye. RESULTS: The present study revealed non-significantly higher morphologically normal oocytes in G3 (74.7%) followed by G2 (70.3%), and the lowest in G1 (66.6%). Morphological defects were observed in 33.3 %, 29.6% and 25.2% of oocytes after cryopreservation in 20% (G1), 30% (G2) and 40% (G3) vitrification solutions, respectively. The results were non-significantly different between vitrification solution groups. However, the viability of post thaw immature oocytes was 95.6%, 84.4% and 81.1% after vitrification in G1 (20%), G2 (30%) and G3 (40%), with viability being significantly highest (P˂0.05) in G1 (20%) and lowest in G3 (40%). CONCLUSION: Cryoprotectant concentrations enable the maintenance of normal morphology and minimize cryoinjury during vitrification of immature oocytes. Keywords: cryoprotectants; immature oocytes; sheep; vitrification.
CryoLetters 42 (6), 326-331 (2021) FOLLICULAR FLUID SUPPLEMENTED WITH COPPER AND ZINC INCREASE THE MATURATION RATE OF MOUSE VITRIFIED-WARMED OOCYTES Shirin Geravandi#1, Azadeh Karami#2, Mehri Azadbakht*1, 1 Department of Biology, Faculty of Basic Sciences, Razi University, Taq-e Bostan, Bagh-e Abrisham, 6714967346, Kermanshah, Iran. Abstract BACKGROUND: Immature oocyte cryopreservation is a therapeutic option in assisted reproductive technology. OBJECTIVE: To evaluate the effects of supplementing oocyte maturation medium with human follicular fluid (hFF), zinc and copper. MATERIALS AND METHODS: Four different maturation media supplemented with 10% follicular fluid, 4 μg/mL copper and 1 μg/mL zinc were used for vitrified-warmed oocytes of mouse. RESULTS: Maturation rate was the highest (63.3%) in the presence of zinc. Cleavage and blastocyst rates in groups with copper and zinc were significantly higher than the control group (39.9% and 46.4% vs. 28.8%), without any significant difference between Zn and Cu. CONCLUSION: Our findings indicate the high importance of using hFF as a natural medium, and also zinc and copper as two efficient trace elements in the maturation medium for vitrified-warmed oocytes. Key words: copper; human follicular fluid; in vitro maturation; vitrification; zinc.
CryoLetters 42 (6), 332-340 (2021) EGG YOLK CAN BE PARTIALLY REPLACED WITH CARBOXYLATED POLY-L-LYSINE (CPLL) IN EXTENDER FOR NILI- RAVI BUFFALO BULL SPERM Shamim Akhter1*, Muhammad Amjad Awan1, Bushra Allah Rakha2, Javeria Arshad1, Muhammad Sajjad Ansari3 and Sajid Iqbal4 1 Department of Zoology, Pir Mehr Ali Shah - Arid Agriculture University Rawalpindi-46300, Pakistan. Abstract BACKGROUND: Egg yolk is inevitably associated with risks of microbial contamination and anti-cryoprotectant agents that necessitate the investigation of some synthetic alternatives. OBJECTIVE: To investigate the potential of carboxylated poly-L-lysine (CPLL) as a replacement for egg yolk during the cryosurvivability of Nili-Ravi buffalo sperm. MATERIALS AND METHODS: Semen collected from four Nili-Ravi buffalo bulls (two ejaculates / bull / day; total 40 ejaculates for five replicates) was cryopreserved in different experimental extenders viz: Control (CPLL 0%, egg yolk 20%); E1 (CPLL 5%, egg yolk 15%); E2 (CPLL 10%, egg yolk 10%); E3 (CPLL 15%, egg yolk 5%) and E4 (CPLL 20%, egg yolk 0%). Post-thaw quality was assessed in terms of sperm motility, plasma membrane integrity (PMI), viability, live:dead ratio, lipid peroxidation of sperm and total antioxidant capacity of seminal plasma. RESULTS: Sperm motility improved (P<0.05) in extenders replacing 5%, 10% and 15% egg yolk with CPLL. Sperm PMI, viability and live:dead ratio also improved (P<0.05) in extenders replacing 10%, 15% and whole (20%) egg yolk with CPLL. In contrast, sperm DNA integrity was not different (P>0.05) when CPLL replaced egg yolk at any level. The lipid peroxidation level decreased with a concomitant increase in total antioxidant activity of seminal plasma when CPLL replaced egg yolk at 5%, 10%, 15% and 20%. CONCLUSION: Replacement of 15% egg yolk in the extender with CPLL improves all sperm quality parameters: motility, PMI, viability, live:dead ratio, lipid peroxidation of sperm and total antioxidant activity of seminal plasma. Keywords: buffalo; carboxylated poly-L-lysine; egg yolk; polyampholyte; sperm.
CryoLetters 42 (6), 341-352 (2021) SCREENING, IDENTIFICATION, PURIFICATION AND HOMOLOGOUS MODELING OF MARINE COLD-ACTIVE ALPHA-AMYLASE Mingjie Lu, Chuanbo Li, Chunying Liu, Naiyu Chi and Shaohua Dou* School of Life Science and Technology, Dalian University, Dalian 116622, China Abstract BACKGROUND: Cold-active α-amylase is essential in industrial production. However, the number of cold-active α-amylases available for use is limited. Screening microbial strains would lay the groundwork for the future development of the food and pharmaceutical industries. OBJECTIVE: To screen microbial strains for cold-active α-amylase based on physiological and biochemical identification, as well as homology modelling. MATERIALS AND METHODS: Cold-active α-amylase strains were screened from water and mud obtained from the Yellow Sea. Colony morphology, Gram staining, scanning electron microscopy and transmission electron microscopy, physiological and biochemical identification and 16S rRNA gene analysis were used to identify strains. A series of steps, including DEAE-anion exchange column chromatography, SephadexG-100 column chromatography, and SDS-PAGE electrophoresis, were used to produce cold-active α-amylase of relatively high purity. Finally, the homology of amylase was modeled to explore the structure and activity site of the enzyme. RESULTS: The named dsh19-1 strain of cold-active α-amylase was screened and identified as Bacillus. The cold-active α-amylase produced by Bacillus was named AmyD-1. The protein with PDB sequence number 5A2B was found to have 40.6% homology with AmyD-1. The verification score of the 3-D model was 137.07 points. We discovered that the six sites are potential sites for amylase to decompose starch by building a 3-D AmyD-1 model. AmyD-1 has a molecular weight of 1515 bp, and hydrogen bonding may be the primary interaction force between AmyD-1 and glucose molecules. CONCLUSION: A cold-active α-amylase produced by Bacillus strain dsh19-1 was successfully obtained and named AmyD-1. This enzyme has potential uses in the food and pharmaceutical industries. Keywords: cold-active α-amylase; homologous modelling; identification; purification.
CryoLetters 42 (6), 353-365 (2021) SEED LONGEVITY AND CRYOBIOTECHNOLOGY IN THE ORCHID GENUS Cattleya Jessica Fontes Fileti1, Mariane M. Hengling1, Thiago M.R. Gianeti2, Hugh W. Pritchard3#, Silvério T. Hosomi1, Nelson B. Machado-Neto4 and Ceci C. Custódio4* 1 Unoeste Campus II, Biology College, Rod. Raposo Tavares Km 572, Bairro Limoeiro, Presidente Prudente SP, Brazil, 19067175. Abstract BACKGROUND: Orchid seeds are reputed to be relatively short-lived, although comparative studies across a wide range of storage temperatures and moisture contents are few. OBJECTIVE: To explore how a wide range of temperature and moisture contents affects seed longevity in the orchid genus Cattleya. MATERIALS AND METHODS: Seeds of three Brazilian orchid species in the genus Cattleya (C. amethystoglossa, C. kautskyana and C. tigrina) were subjected to controlled deterioration (CD) and seeds at three moisture levels were stored for up to 270 days at temperatures as low as -196°C. Seed ageing curves were constructed and seed quality assessed as germination level and speed index in vitro, and by tetrazolium staining. Seed morphometry, lipid content and composition were also determined. RESULTS: Seeds were found to be lipid rich (54-70% DW) and short-lived under CD, with P50s varying less than two-fold (42 to 69 h) at 41°C. At cold (5°C) to ultracold (-196°C) temperatures longevity was greatest after pre-drying seeds to 15% RH, with germination varying by c. 6% after 270 days storage at these temperature limits. However, storage at -20°C resulted in a 5-46% reduction in germination, indicating a dry-seed sensitivity to conventional seed bank temperature. Ultra-dry (silica gel) and high humidity (82% RH) storage, in combination with various temperatures, compromised viability in one or more species. Overall, seed longevity in C. kautskyana > C. tigrina > C. amethystoglossa, which also reflected the pattern of embryo volume. The prospect that the generally shorter lifespans in orchid seeds may relate to stochastic processes the negative impact of which reach criticality sooner in smaller embryos requires further testing. CONCLUSION: Further evidence is provided that cryobiotechnology provides a biobanking option for orchid seeds with relatively short lifespans. Keywords: conservation; cryopreservation; longevity; Orchidaceae; seed banking; seed lipid content; storage.
CryoLetters 42 (6), 366-379 (2021) ABSTRACTS: 56th MEETING OF THE SOCIETY FOR LOW TEMPERATURE BIOLOGY 7-9 OCTOBER 2020 (ONLINE) IN ASSOCIATION WITH UCLOUVAIN, BELGIUM ABSTRACTS (PDF) |
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For Abstracts published from meetings, such as SLTB meetings, go to the
relevant Volume Year of the journal (above). For Full text Free Access Content (from 2000 onwards) go to CryoLetters at Ingenta and look for the blue symbol. |
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