During embryogenesis in Danio rerio (zebrafish), the earliest morphological patterning events are dependent on the precise temporal translation and/or localization of specific maternal mRNAs/proteins. Dorsoventral patterning in particular requires the translocation of maternal factors that are present in the Balbiani Body from the vegetal region of the unfertilized egg to the future dorsal side of the embryo (Fuentes et al., 2020), leading to the localized activation of the β-catenin pathway in the cells in that region. Since zebrafish are chordates, this dorsoventral patterning then leads to the formation of neural tissue on the dorsal side of the embryo. What is not yet clear is the identity of all maternal and zygotic factors that first establish dorsoventral patterning, and which factors lead to the establishment of neural versus non-neural tissue. Taking an evolutionary approach to this question, we investigated a gene in zebrafish, zsquidlike-A (hnrnpaba), that is homologous to a key dorsoventral patterning gene in fruit flies (Drosophila melanogaster) called squid (Kelley, 1993). While dorsoventral patterning in flies and fish looks quite different both morphologically and at the molecular level, we demonstrate that not only has a key dorsoventral patterning gene in flies been conserved in fish, maternal fish zsquidlike-A protein is synthesized precisely as dorsoventral patterning is unfolding in fish embryos, and in its absence, dorsoventral patterning is severely disrupted.

Recently, the World Health Organization recommendation for abstinence time for semen analysis has been challenged in some studies and many of them have supported the advantages of a second short abstinence ejaculation. More evidence is needed to approve this for clinical use. This study aimed to compare the average routine abstinence time (2–7 days) with the short time (1–2 h) on sperm quality based on functional parameters in a population of oligo-astheno-teratozoospermia (OAT) men. The semen samples were retrieved from 50 men with OAT two times: one standard 2–7 days (long ejaculation) and short duration trimming (1–2 hours later the first ejaculation). All semen parameters as well as sperm DNA integrity were compared between groups. Results showed that mean sperm concentration (10.40 vs. 8.76), total sperm count (28.53 vs. 12.24) and mean semen volume (2.69 vs. 1.40) were higher in the first ejaculation (2–7 days of abstinence), while progressive motility (20.52 vs. 13.32), non-progressive motility (53.46 vs. 48.86), morphology (2.46 vs. 1.46) and viability (83.90 vs. 77.96) were significantly higher in the second ejaculation (P < 0.05). The second sample also showed lower immotile (26.82 vs. 38.02) and DNA fragmentation (19.5 vs. 26.96) (P < 0.05). Taking all data into account, an additional short abstinence period (AP) may be a simple and helpful strategy to obtain better sperm quality in couples with male infertility causes, especially in OAT patients. The recommended current guidelines regarding the AP may need to be revisited in severe male factors.

In cattle, maternal metabolic health has been suggested to influence oocyte and embryo quality. Here, we examined whether maternal liver abnormalities affected in vitro oocyte maturation by screening meiotic maturation, spindle morphology, actin filaments, and lysosomes. In oocytes from the abnormal liver group, the maturation rate (80.2%) was significantly lower compared to a control group with healthy livers (90.8%; P < 0.05). Mean spindle area in oocytes of the abnormal group (50.4 ± 3.4 μm2) was significantly larger than in the control (40.8 ± 1.6 μm2; P < 0.05). Likewise, mean spindle width in the abnormal group (8.8 ± 0.3 μm) was significantly larger than in the control group (7.8 ± 0.2 μm; P < 0.05). The proportion of cells with correctly aligned chromosomes in the abnormal group (48.0%) was significantly lower than in the control (78.3%; P < 0.05). The number of cortical actin filaments in mature oocytes of the abnormal group (299.3 ± 3.7) was significantly lower than in the control (314.7 ± 3.2; P < 0.05). The number of lysosomes in mature oocytes of the abnormal group (1363.6 ± 39.0) was significantly higher than in the control (1123.4 ± 26.3; P < 0.05). In conclusion, our findings indicate that the quality of in vitro matured oocytes is lower in cattle with liver abnormalities than in healthy cattle.

Introduction: Long non-coding RNAs (lncRNAs) are a subset of RNA molecules that have been shown to be involved in gene regulation. A lot of different pathways are involved during gametogenesis and any disturbance to these pathways may have a derogatory impact on producing a haploid gamete and thus a euploid embryo. Steroidogenesis pathway plays a crucial role in gametogenesis. The purpose of this work was to quantify the levels of lnc-CYP11A1-1 and RP11573D15.8 expression levels in aneuploid and euploid embryos. Materials and methods: A total of 20 surplus human embryos, of which 10 euploid and ten aneuploid embryos, were collected from an IVF centre. The expression levels of two lncRNAs, which have been hypothesized to regulate expression of CYP11A1, were evaluated in these embryos. RNA was extracted and used to synthesize cDNA for the experiments. Real-time polymerase chain reaction was performed to evaluate the expression levels of each lncRNA in aneuploid and euploid embryos, respectively. Results and discussion: This study shows that lnc-CYP11A1-1 was more expressed in aneuploid than in euploid embryos. RP11-573D15.8 is expressed more in aneuploid embryos than in euploid ones. The results for RP11-573D15.8 were statistically significant with a p-value of 0.02 (less than the standard threshold of p 0.05), whereas the results for lnc-CYP11A1-1 were not statistically significant with a p-value of 0.07 (greater than the standard threshold of p 0.05). Thus, the result of this study demonstrates that lncRNAs may have a role in gametogenesis and formation of aneuploid gametes.

This study explores the efficacy of a novel microfluidic device in isolating rheotactic sperm and assesses their advantages compared with other motile sperm. Two microfluidic devices were used in this study: the microfluidic device we designed to separate sperm based on rheotaxis and a simple passive microfluidic device. We compared the results with the density gradient centrifugation technique. Sperm attributes including concentration, morphology, viability and motility were assessed using related procedures. Statistical analyses were conducted using one-way analysis of variance. Results showed differences in sperm concentration, motility, morphology and vitality using different sperm separation techniques. The sperms separated using our microfluidic device demonstrated the highest motilities, normal morphology percentages and higher sperm vitality but significantly lower sperm concentrations. These findings suggest the potential of our microfluidic design in enhancing sperm quality. Our findings are in agreement with previous research, emphasizing the capability of microfluidics in enhancing sperm quality. Specifically, our designed microfluidic device exhibited exceptional efficacy in isolating highly motile sperm, a critical factor for successful fertilization.

Rainbow trout (Oncorhynchus mykiss) is a promising cultivable fish species with significant potential for expansion. As a cold-water fish belonging to the Salmonidae family, it requires an optimal temperature range of 10–15°C for optimal growth. This study explores a method for producing sterile rainbow trout with maximum survival rates by using heat shock treatment to enhance growth characteristics and improve aquaculture practices. A control group and four heat shock treatments were given at 26°C and 28°C for 10 min, applied 15 and 20 min after the mixing of eggs and milt, using a water bath. Among the treated groups, the highest fertilisation, hatching and yolk sac absorption rates were 90.3 ± 0.3%, 81.8 ± 0.8% and 83.9 ± 0.5%, respectively. The highest triploidy rate of 76.6 ± 3.3% was observed with a heat shock at 28°C, 20 min after fertilisation. In contrast, none of the fish from the control group were triploids. The control group demonstrated higher survival rates at fertilisation (93.1 ± 0.4%), hatching (84.2 ± 0.4%) and complete yolk sac absorption (86.2 ± 0.5%) compared to the heat-shocked groups. The diploid and triploid chromosome numbers in rainbow trout were determined to be 2n = 60 and 3n = 91, respectively. This study confirms that heat shock treatment can effectively induce triploidy in rainbow trout, with significant variations in triploidy rates depending on the temperature and timing of the shock. While heat shock can enhance the production of sterile fish, it is essential to balance the treatment parameters to maintain high survival rates. These findings contribute to the optimisation of triploidy induction techniques and support the advancement of aquaculture practices by improving the growth, management and survival rates of rainbow trout which could significantly benefit aquaculture efficiency and sustainability.

Treatment with follicle-stimulating hormone (FSH) and testosterone (T2) and their combination have been observed to be influential on ovarian follicles of 1-day-old mice ovaries cultured for 8 days. Given that extension of the culture period could positively impact the development of follicles in cultured ovaries, the present study was conducted to evaluate the main and interaction effects of FSH by T2 on the development of ovarian follicles in 1-day-old mice ovaries cultured for 12 days. One-day-old mice ovaries were initially cultured with base medium for 4 days; thereafter, different hormonal treatments were added to the culture media, and the culture was continued for 8 additional days until day 12. Ovaries were collected for histological and molecular assessments on day 12. The greatest activation of primordial follicles and progression of activated follicles to the preantral stage was detected in ovaries treated with the combination of FSH and T2 (P < 0.05). This positive effect on the morphology of ovarian follicles was accompanied by upregulation of Pi3k, Gdf9, Bmp15, Cx37 and Fshr in the ovaries cultured with the combination of FSH and T2 (P < 0.05). Nonetheless, treatment with FSH and T2 led to a diminished proportion of intact follicles (P < 0.05), even though Bax/Bcl2 gene expression ratio, as an apoptotic index, was less in hormone-treated ovaries (P < 0.05). In conclusion, the combination of FSH and T2 could improve the activation of primordial follicles and the growth of activated follicles towards the preantral stage. This positive effect of FSH plus T2 appeared to be at least partly mediated through the upregulation of Pi3k and oocyte-derived growth factors including Gdf9 and Bmp15.

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.