Long-term trophectoderm (TE) cell culture provides a powerful model to investigate placenta-specific factors to better understand mechanisms relevant to pregnancy establishment and placental development. However, current TE culture systems rely on costly commercial media and extracellular matrix (ECM) components, which limit their scalability and accessibility. This study evaluated cost-effective alternatives to established conditions by testing modified DMEM/F-12 and a biphasic TE culture system as substitutes for commercial Advanced DMEM/F-12 and for continuous TE culture, and by assessing 0.1% gelatine as an ECM alternative to collagen IV. Trophectoderm outgrowths cultured on collagen IV or gelatine did not differ in attachment timing (P = 0.78) or in expression of placental and differentiation markers PLAC8 (P = 0.78), GATA2 (P = 0.18), and PAG10 (P = 0.39). Similarly, blastocysts cultured in commercial Advanced DMEM/F-12 or base DMEM/F-12 exhibited no differences in attachment day (P = 0.98), TE growth area from days 10–20 (P > 0.05), or expression of PLAC8 (P = 0.35) and PAG10 (P = 0.08), although PAG7 differed between treatments (P < 0.05). Embryos cultured in continuous TE attached later (P = 0.01) than those cultured in TE media, but no differences were observed in TE growth area or expression of PLAC8, PAG7, or PAG10 (P > 0.05). Collectively, these results indicate that affordable media formulations and gelatine-coated cultureware support TE attachment, proliferation, and differentiation. This cost-effective culture framework enables broader application of TE models and supports extended studies of trophoblast function, placental signalling, and early conceptus development.

Oocyte maturation is regulated by well-orchestrated molecular mechanisms and any abnormalities during these events could result in an oocyte that cannot be fertilized or develop into normal embryos. Recently, MOS gene variants were reported to result in oocytes with large polar body (PB) or early embryonic arrest in humans leading to infertility. A thirty-year-old woman with 12 years of infertility underwent two in vitro fertilization cycles, and in both she had oocytes with large PBs and parthenogenetic activation. Clinical exome sequence was performed and revealed a novel homozygous variant in MOS (NM_005372.1):c.573C > A;p.(Phe191Leu). These findings might indicate that MOS mutation results in oocytes with a large PB and parthenogenesis in this patient. In conclusion, our data further confirms that MOS is important in proper oocyte maturation, and variant c 573 C > A results in the formation of a large PB and parthenogenetic activation as reported in animal models earlier. Patients with MOS variants need to be counselled about their fertility status.

The piracanjuba (Brycon orbignyanus) is a species threatened with extinction due to human activities, highlighting the need for genebanking and alternative propagation methods for its conservation. The objective of this study was to obtain a completely sterile yellowtail tetra (Astyanax altiparanae) and to transplant the stem spermatogonia (SSCs) of B. orbignyanus. Complete depletion of spermatogenesis in adult diploid males was successfully achieved through five applications of busulfan, using dosages of 15 mg kg−1 and 40 mg kg−1 at a high temperature of 35°C. One month after completing the busulfan treatment, spermatogenesis returned, occurring more rapidly in the 15 mg kg−1 treatment, with spermatozoa visible in the testicular lumen. In the treatment with 40 mg kg−1, only SSCs and some spermatid cysts were observed. Depletion of spermatogenesis in triploid juveniles was observed after two applications of busulfan (50 mg kg−1). One month after the end of the treatment, only a few SSCs cells were observed in the testes. The B. orbignyanus SSCs were isolated using a Percoll density gradient and identified by alkaline phosphatase activity, resulting in a cell suspension of 2.6 × 106 SSCs/mL with 93% cell viability. The cells were labeled with PKH26 and transplanted via the urogenital papilla into recipients (triploid juvenile males) previously treated with busulfan. PKH26-positive cells were visualized up to 80 days after transplantation. The combination of two sterilization methods appears to be more effective for cell transplantation after the endogenous germ cells have been eliminated from the recipient testes of triploid juveniles.

This study investigated how hormonal induction, female presence, and production system affect sperm quality in Astyanax lacustris across three experiments. In Experiment 1, males and females were kept together in the same recirculating aquaculture system (RAS) before testing. Hormonal induction consistently boosted initial motility and prolonged sperm activity, while female presence offered only a modest benefit to non-induced males and no measurable effect when males were induced. Sperm concentration remained similar across treatments. Experiment 2 evaluated the same factors using broodstock originating from different rearing environments. When males and females came from separate RAS units, hormonal induction again sustained higher motility, and induced males paired with females showed higher sperm concentration than some non-induced groups. In the RAS–biofloc technology (BFT) pairing, hormonal induction maintained motility regardless of female presence; however, in the absence of hormonal induction, both sperm motility and concentration were modulated by the rearing system of females, with non-induced males paired with BFT females exhibiting lower reproductive performance. Overall, hormonal induction proved to be the most reliable strategy for ensuring high semen quality in A. lacustris. Nonetheless, when induction was not applied, male reproductive performance became more sensitive to female origin and rearing environment, highlighting the importance of broodstock compatibility and production system history in reproductive management protocols.

Zygote wishes to inform its readers that its Editor-in-Chief has decided to retract the above article after an investigation carried out in compliance with the Committee on Publication Ethics guidelines found that the authors duplicated substantial parts of the following two articles:

1. 1. Kim H, Yamanouchi K, Nishihara M. (2006) Expression of ski in the granulosa cells of atretic follicles in the rat ovary. J. Reprod. Dev. 52, 715–721

2. 2. Kim H, Yamanouchi K, Matsuwaki T, Nishihara M. (2012) Induction of Ski protein expression upon luteinization in rat granulosa cells without a change in its mRNA expression. J. Reprod. Dev. 58, 254–259

Sloan-Kettering virus gene, a product of a cellular proto-oncogene c-Ski is a unique nuclear pro-oncoprotein and belongs to the Ski/Sno proto-oncogene family. The aim of the present study was to locate Ski protein in rat ovaries in order to find insights into the possible involvement of Ski in follicular development. First, expression of c-Ski mRNA in the ovaries of adult female rats was confirmed by RT-PCR. Then, ovaries obtained on the day of estrus were subjected to immunohistochemical analysis for Ski and proliferating cell nuclear antigen (PCNA) in combination with terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL). RT-PCR and in situ hybridization revealed that c-Ski mRNA was expressed in the ovaries of the adult rat on the day of estrous and localized mainly in the granulose cells. Ski was expressed in granulosa cells that were positive for TUNEL, but negative for PCNA, regardless of the shape and size of follicles. Expression of Ski in TUNEL-positive granulosa cells, but not in PCNA-positive granulosa cells, was also verified in rats having atretic follicles with double staining. These results indicate that Ski is profoundly expressed in the granulosa cells of atretic follicles, but not in growing follicles. Based on the present findings, Ski may play a role in the apoptosis of granulosa cells during follicular atresia.