Cryo letters最新文献

Background: Successful cryopreservation of bovine oocytes is very important for research and commercial applications. However, the survival and development rate of vitrified-thawed (VT) oocytes are lower than those of non-vitrified-thawed (non-VT) oocytes.

Objective: To investigate the effect of adding hydroxypropyl cellulose (HPC) to the vitrification solution for bovine oocytes.

Materials and methods: For vitrification, bovine metaphase II oocytes were pretreated with a solution containing 10% ethylene glycol supplemented with 0, 10, 50, or 100 ug/mL HPC for 5 min, exposed to a solution containing 30% ethylene glycol supplemented with 0, 10, 50, or 100 ug/mL HPC for 30 s, and then directly plunged into liquid nitrogen.

Results: The survival rate of oocytes was significantly higher in the 50 HPC group than in the 0, 10, and 100 HPC groups. The reactive oxygen species level was lower in the non-VT and 50 HPC groups than in the other groups. The mRNA levels of proapoptotic genes (Bax) were lower in the non-VT, 0, and 50 HPC groups than in the other groups. The mRNA levels of antiapoptotic genes (BCl2) were higher in the non-VT than in the other groups. The development rates of embryos (day 8) obtained via parthenogenetic activation (PA) were determined in the non-VT, 0 HPC, and 50 HPC groups. The cleavage rate was significantly higher in the non-VT group.

Conclusion: Supplementation of vitrification solution with HPC improves the survival of VT bovine oocytes and the development capacity of embryos derived from these oocytes via PA. doi.org/10.54680/fr23110110212.

Cryopreservation of pollen grains is an effective means of conserving desired germplasm of crop plants. Cryoconserved pollen are expected to be long-lived and thus can be suitably retrieved to overcome hybridization constraints imposed by a variety of reasons. We ascertained the performance of oil palm pollen grains (Tenera hybrids) that were cryobanked 23 years ago using liquid nitrogen (-196 degree C). Cryostored pollen were assessed for viability, in-vitro germinability and vigour. Our analysis showed a marginal decline in viability, assessed through fluorochromatic reaction test, of cryopreserved pollen as compared to fresh ones (pre-storage assessment); however, the viability did not decline in the cryostate since it was last tested 15 years back. On the other hand, germinability and vigour of cryopreserved pollen were maintained to the levels of fresh pollen. Our study, for the first time, demonstrates the amenability of pollen grains for cryopreservation of any plant species beyond a period of two decades in general, and that for oil palm in particular. doi.org/10.54680/fr23110110512.

Background: Longan honey (LH) has the potential as a natural extracellular cryoprotectant to maintain the integrity of intact preantral follicles against the cryoinjury during ovarian vitrification.

Objective: This research determined the cryoprotective effects of logan honey on preantral follicles integrity of rat ovary post-vitrification.

Materials and methods: After vitrification, the follicle index was determined by observing the ovarian histological sections made using the paraffin method with hematoxylin-eosin staining and analyzed using Optilab 3.0 and Image Raster software.

Results: The results showed that the combination of ethylene glycol (EG) with LH and a dose variation of 7.5 %-15 % (KP1-KP4) increased the density of follicles, the number of intact follicles in G2 and G3, with a decrease in the atretic follicles in G1 better compared to the use of EG only (KKP1-KKP2). The differences in the histological structur e of preantral follicles affected the doses of LH needed by each type of follicle to maintain the integrity of the follicular structure from cryoinjury effects. The comparison of the G2 total follicle index values were KKP1 (90.7 ± 18.3), KKP2 (115.6 ± 9.9) < KP1 (193.6 ± 10.7), KP2 (189.3 ± 10.5), KP3 (182.2 ± 27.1) and KP4 (169.4±8.8). Among the variations in the dose of LH 7.5 % - 15%, the highest increase in the G3 index value was found in primary (51.7 ± 9.8), tertiary (43.1 ± 8.8), secondary (33.9 ± 4.7), and primordial (28.7 ± 2.5) follicles of KP3 (7.5 % of LH).

Conclusion: The primary and tertiary follicular stages maintain the best integrity and can be used after the vitrification of rat ovaries. doi.org/10.54680/fr23110110712.

Background: The bacterial contaminants in the semen are a major concern for most of the semen production laboratories because they adversely affect the semen quality. During sperm cryopreservation, the inclusion of antimicrobials in extenders may help to minimize bacterial growth. However, due to bacterial resistance to commonly used antimicrobials, they cannot fully assure microbiological safety to the frozen semen.

Objective: To estimate the microbial load and antibiogram of microorganisms isolated from the fresh and frozen bull semen.

Materials and methods: The bacterial load was estimated in fresh and frozen semen samples of crossbred Frieswal bulls by the pour plate method. Microorganisms were identified as Gram positive and Gram negative by Gram staining. The representative bacterial colonies were streaked onto different specific media which were further confirmed by biochemical tests. Bacterial isolates were subjected to in vitro antibiotic sensitivity test.

Results: The average microbial load of fresh and frozen semen samples was found to be 8397.4 ± 524.3 cfu per mL and 680.9 ± 105.4 cfuper mL, respectively. Microorganisms belonging to Staphylococcus aureus, Staphylococcus epidermidis, Proteus, Klebsiella, Bacillus cereus, Bacillus subtilis, Actinomyces, E. coli, Rhodococcus, Neisseria and Micrococcus were identified in the semen samples. The antibiotic sensitivity testing of the bacterial isolates revealed that benzyl penicillin was found to be the least effective against the isolated organisms while gentamicin and spectinomycin were found to be most effective among the antibiotics used. Lincomycin, tylosin and streptomycin showed moderate efficacy against the bacterial isolates.

Conclusion: Gentamicin, tylosin, lincomycin, and spectinomycin (GTLS) antibiotic combination is more effective against bacterial isolates and may be added to semen extender to better control bacterial load and semen quality. doi.org/10.54680/fr22610110512.