The creation of a Taraxacum kok-saghyz high frequency regeneration system

The aim of this research was to study the morphogenetic ability of Taraxacum kok-saghyz root tissues and to optimize the culture medium for the subsequent genetic transformation of plants. The effects of exogenous hormone exposure on survival, in vitro shoot induction, and root formation were studied by using root tissues. For the cultivation the samples of kok-saghyz, the Murashige-Skuga nutrient medium was used as the basis, supplemented with sucrose 20 g/l, vitamins B5 1 mg/l, and also containing agar 5.5 g/l. The pH value is 5.7. For the plant regeneration induction, growth regulators, auxins and cytokinins were added in culture media. In this study, the roots of D 1 mm and two media variants were used for comparison: variant 1. MS + 6-BAP 1 mg/l; variant 2. MS + 6-BAP 1 mg/l + IAA 0.2 mg/l. An effective protocol for the regeneration of kok-saghyz explants was developed. There was a high percentage of regeneration of 87.6% on the medium containing a combination of cytokinin and auxin, as well as a high percentage of direct shoot formation, which was 65.1%, the degree of rooting was 100%, the resulting cultured plant tissues grew well and had a high survival rate after transplantation.

Is maternal thyroid hormone deposition subject to a trade-off between self and egg because of iodine? An experimental study in rock pigeon

Maternal hormones constitute a key signalling pathway for mothers to shape offspring phenotype and fitness. Thyroid hormones (THs; triiodothyronine, T3 and thyroxine, T4) are metabolic hormones known to play crucial roles in embryonic development and survival in all vertebrates. During early developmental stages, embryos exclusively rely on the exposure to maternal THs, and maternal hypothyroidism can cause severe embryonic maldevelopment. The TH molecule includes iodine, an element that cannot be synthesised by the organism. Therefore, TH production may become costly when environmental iodine availability is low. This may yield a trade-off for breeding females between allocating the hormones to self or to their eggs, potentially to the extent that it even influences the number of laid eggs. In this study, we investigated whether low dietary iodine may limit TH production and transfer to the eggs in a captive population of Rock pigeons (Columba livia). We provided breeding females with an iodine-restricted (I- diet) or iodine-supplemented diet (I+ diet) and measured the resulting circulating and yolk iodine and TH concentrations and the number of eggs laid. Our iodine-restricted diet successfully decreased both circulating and yolk iodine concentrations compared to the supplemented diet, but not circulating or yolk THs. This indicates that mothers may not be able to independently regulate hormone exposure for self and their embryos. However, egg production was clearly reduced in the I- group, with fewer females laying eggs. This result shows that restricted availability of iodine does induce a cost in terms of egg production. Whether females reduced egg production to preserve THs for themselves or to prevent embryos from exposure to low iodine and/or THs is as yet unclear.

Steroid Hormone Exposure as a Potential Hazard in Milk Consumers: A Significant Health Challenge in Iran

The presence of steroid hormones in milk is inevitable, and they can be considered as potential carcinogenic agents for consumers. The purpose of this study was to evaluate the level of 17β-estradiol, progesterone, and hydroxyprogesterone in sixty-nine bovine milk samples, collected from April to September 2020, in Hamadan, Iran. The milk samples were analyzed using enzyme-linked immunosorbent assay (ELISA). In this study, the mean contents of 17β-estradiol, progesterone, and hydroxyprogesterone in the milk samples were determined to be 330.5 ± 190.2 pg/ml, 3.57 ± 2.47 ng/ml, and 1.54 ± 0.41 ng/ml, respectively. However, the content of these steroid hormones in milk samples could be considered safe in children and adults, if the milk consumption is assumed to be in the reported range (175–240 ml/daily). Due to the effects of steroid hormones, especially 17β-estradiol, in the etiology of various cancers, regular monitoring of these hormones is recommended in milk and its dairy products in Iran.

Reproductive Deficits Induced by Prenatal Anti-Mullerian Hormone Exposure Require Androgen Receptor in Kisspeptin Cells

Polycystic ovary syndrome (PCOS) is a common reproductive disorder characterized by elevated androgens and anti-Mullerian hormone (AMH). These hormones remain elevated throughout pregnancy, and potential effects of hormone exposure on offspring from women with PCOS remain largely unexplored. Expanding on recent reports of prenatal AMH exposure in mice, we have fully characterized the reproductive consequences of prenatal AMH (pAMH) exposure throughout the lifespan of first- and second-generation offspring of both sexes. We also sought to elucidate mechanisms underlying pAMH-induced reproductive effects. There is a known reciprocal relationship between AMH and androgens, and in PCOS and PCOS-like animal models, androgen feedback is dysregulated at the level the hypothalamus. Kisspeptin neurons express androgen receptors and play a critical role in sexual development and function. We therefore hypothesized that pAMH-induced reproductive phenotypes would be mediated by androgen signaling at the level of kisspeptin cells. We tested the pAMH model in kisspeptin-specific androgen receptor knockout (KARKO) mice and found that virtually all pAMH-induced phenotypes assayed are eliminated in KARKO offspring compared to littermate controls. By demonstrating the necessity of androgen receptor in kisspeptin cells to induce pAMH phenotypes, we have advanced understanding of the interactions between AMH and androgens in the context of prenatal exposure, which could have significant implications for children of women with PCOS.

Associations between female lung cancer risk and sex steroid hormones: a systematic review and meta-analysis of the worldwide epidemiological evidence on endogenous and exogenous sex steroid hormones

Background Published findings suggest sex differences in lung cancer risk and a potential role for sex steroid hormones. Our aim was to perform a meta-analysis to investigate the effects of sex steroid hormone exposure specifically on the risk of lung cancer in women. Methods The PubMed, MEDLINE, Web of Science, and EMBASE databases were searched. The pooled odds ratios (ORs) and 95% confidence intervals (95% CIs) for female lung cancer risk associated with sex steroid hormones were calculated overall and by study design, publication year, population, and smoking status. Sensitivity analysis, publication bias, and subgroup analysis were performed. Results Forty-eight studies published between 1987 and 2019 were included in the study with a total of 31,592 female lung cancer cases and 1,416,320 subjects without lung cancer. Overall, higher levels of sex steroid hormones, both endogenous (OR: 0.92, 95% CI: 0.87–0.98) and exogenous (OR: 0.86, 95% CI: 0.80–0.93), significantly decreased the risk of female lung cancer by 10% (OR: 0.90, 95% CI: 0.86–0.95). The risk of lung cancer decreased more significantly with a higher level of sex steroid hormones in non-smoking women (OR: 0.88, 95% CI: 0.78–0.99) than in smoking women (OR: 0.98, 95% CI: 0.77–1.03), especially in Asia women (OR: 0.84, 95% CI: 0.74–0.96). Conclusions Our meta-analysis reveals an association between higher levels of sex steroid hormone exposure and the decreased risk of female lung cancer. Surveillance of sex steroid hormones might be used for identifying populations at high risk for lung cancer, especially among non-smoking women.

Spermatogonial Dio3 as a Potential Germ Line Sensor for Thyroid Hormone-Driven Epigenetic Inheritance

Summary Sentence: Thyroid hormone-clearing type 3 deiodinase is located in spermatogonia, where it may serve as a critical modulator of the thyroid hormone exposure of the male germ line and its epigenetic information, with implications for neurodevelopmental and endocrine disorders in subsequent generations.

Homeodomain Transcription Factors: Integral Modulators of Human Decidualization

Ineffective embryo implantation accounts for a significant percentage of female infertility, and often renders IVF procedures unsuccessful. Decidualization, the dramatic uterine morphological response to ovarian hormone exposure, is a prerequisite for embryo implantation. Despite its significance in reproduction, the genetic framework of decidualization was not systematically studied until our recent development of a suitable high-throughput screening tool, immortalized human endometrial stromal cells (hESCs) that carry the yellow fluorescent protein gene under the control of the progesterone-sensitive prolactin promoter (PRL-Y cells). We recently used PRL-Y cells to perform a genome-wide siRNA functional screen and results revealed that 36 members of the homeodomain-containing family of transcription factors (HDTFs) are modulators of human decidualization. To determine which HDTFs are transcriptionally sensitive to ovarian hormone exposure, RT-PCR was performed on wildtype hESCs for the 36 HDTF hits over a 72-hour time course of E2/P4/cAMP exposure. Twenty HDTF hits (55%) were both detectable by PCR and showed variable expression in response to ovarian hormone treatment. Interestingly, all of these homeodomain factors, with a few distinct exceptions, exhibited decreased transcriptional expression in response to ovarian hormone treatment. This suggests that precious energy is used to transcribe these factors during the pre-decidualized phase, and that they may be required to maintain homeostasis during times of low hormone exposure. Because siRNA is not fully efficient, in order to confirm which HDTFs are required for normal decidualization, we generated a doxycyline-inducible Cas9-expressing hESC clone in order to subsequently generate individual knockout hESC lines for each HDTF hit. Cas9 expression was turned on 5 days prior to crRNA and trRNA transfection targeting the first exon of each HDTF. Five days after transfection, the cells were treated for 72 hours with ovarian hormone induction medium before RNA was isolated for gene expression analysis. As a pool of cells prior to any cloning (which likely includes knockout and wildtype cells in different ratios) the results indicate that several HDTFs are required for proper decidualization. The reporter transcripts of PRL and EREG are significantly abrogated or entirely undetectable in certain knockout lines. Interestingly these include some original siRNA HDTF hits whose expression is undetectably low by PCR. Sequencing validation will be necessary to confirm that knocking out such low levels of these transcripts genuinely has the robust effect on the human decidualization reaction that we are witnessing in these results. Together these findings comprise significant initial steps in characterizing the intricate upstream roles of HDTFs in human decidualization and female fertility.