Injecting growth hormone
A cDNA encoding a cuticle protein containing the R&R Consensus was characterized in the honeybee integument. AmelCPR14 developmental expression is distinguished by an on-off-on pattern, the transition from a low to a high level of transcripts occurring as the ecdysteroid titer is declining after the peak that triggers the onset of pharate (pupal and adult) development. The transcript is abundant during cuticle tanning and sclerotization, and persists even in the adult integument, suggesting that the corresponding protein is required for differentiation and maintenance of the adult cuticle. Such developmental pattern suggested that AmelCPR14 gene might be regulated by the titer of ecdysteroids. We confirmed this hypothesis using different experimental strategies. By tying a ligature in early pupae to prevent exposure of abdominal integument to a high ecdysteroid titer, we delayed the accumulation of AmelCPR14 transcripts in the abdominal integument. This is consistent with ecdysteroid priming being required in pupae for the increase in AmelCPR14 expression in pharate adults. By injecting 20-hydroxyecdysone (20E) in early pupae we demonstrated that hormone titer decay after the peak is critical for AmelCPR14 expression induction. Exposure of pupal integument in vitro to a 20E concentration mimicking the pupal ecdysteroid peak repressed AmelCPR14 expression, which was recovered by hormone removal. Taken together, these data are consistent with an ecdysteroid pulse (increase in hormone titer followed by its decline) being critical for a high AmelCPR14 gene expression in pharate adults.
Knowledge about management of ovulation in the donkey is limited compared to that in the horse. This experiment was designed to evaluate the efficacy of injecting single doses of lecirelin (a GnRH-analogue) or of hCG to induce ovulation in the jenny and to determine whether effects are dependent upon follicular diameter at time of injection. Ovarian activity and follicular growth were monitored by rectal ultrasonography. Jennies were randomly allotted to the following groups: Group GnRH, treated with 100 microg lecirelin; Group hCG, treated with 2500 IU hCG; Group C, untreated and monitored for spontaneous ovulation. Animals were also categorized into subgroups depending upon follicular diameter: 30-35 mm (GnRH-1, hCG-1 and C-1) or 36-40 mm (GnRH-2, hCG-2 and C-2). Jennies in the two hormone treatment groups did not differ significantly for time from treatment to ovulation, but there was a significant reduction in time to ovulation as follicle size at treatment increased. Jennies treated with either lecirelin or hCG had significantly smaller follicle size at ovulation than jennies in the Control groups that underwent spontaneous ovulation. Treatment groups did not differ significantly in the proportion of jennies that ovulated within 48 h of injection or between 25 and 48 h following injection. These results highlight the usefulness of lecirelin for induction and synchronization of ovulation in the jenny, particularly since it would avoid the risk of reduced hCG response in reproductive management programs in which that hormone was repeatedly used.
The cDNA and genomic DNA of zebrafish (Danio rerio) protein kinase Cmu (PKCmu), with its promoter region, were obtained. The 508-amino acid zebrafish PKCmu has 86.17% similarity to human PKCmu. Real-time reverse-transcription polymerase chain reaction analysis with starvation and hormonal treatment found significant differences between the control group and the experimental group after 14 days of starvation. After injecting insulin-like growth factor II (IGF-II), growth hormone (GH), insulin, or human chorionic gonadotropin, significant differences were observed between the control and experimental groups 24 h after treatment. After injecting the gonadotropin-releasing hormone or luteotropin-releasing hormone, significant differences were seen between the control and experimental groups 15 h after treatment. These results suggest that in vivo PKCmu expression is regulated by the insulin family or by the GH, but other sex hormones produced a significant expression level more quickly than the insulin family and GH. The zebrafish PKCmu gene is located on zebrafish chromosome 17 and consists of 16 exons. A 2.6 kilobase pair on the 5' flanking region displayed maximal promoter activity in the zebrafish liver (ZFL) cell line after treatment with IGF-I, IGF-II, and GH. However, a 1.6 kilobase pair on the 5' flanking region displayed maximal promoter activity in the HeLa cell line after treatment with IGF-I, IGF-II, and GH. Finally, PKCmu may have important nuclear effects on cell growth and may involve nuclear localization. By transiently transfecting ZFL cells with various zebrafish PKCmu segments, we identified a nuclear localization signal: the amino acid sequence between amino acids 206 and 209 was able to predominantly direct enhanced green fluorescence protein (EGFP) into the nucleus, whereas a deletion of this motif abrogated the nuclear localization property.
