Period Of Embryonic Development Research Articles

Формирование поверхностной грудной мышцы и четырехглавой мышцы бедра у кур мясного направления продуктивности в эмбриогенезе

Morphological and histological characteristics of the quadriceps femoral muscle and the superficial pectoral muscle in chickens of the meat productivity direction (Brama and Smena-8) on the 14th day of embryogenesis are shown. In the studied muscles, muscle fibers were identified, delimited by the endomysium and combined into bundles, between which the perimysium lies. There is no transverse striation in the muscle fibers. In the structure of the skeletal muscles of the Smena-8 cross, the division of muscle fibers into thin and thick is established. During the study, the thickness of muscle fibers and their bundles, as well as the thickness of the endomysium and perimysium were determined. According to all the studied micromorphometric indicators of the quadriceps femoral muscle and the superficial pectoral muscle, the superiority of the Smena-8 cross over the Brama breed was revealed. The presented results indicate the peculiarities of the formation of skeletal muscles on the 14th day of the embryonic period of development of the organism in chickens of the meat productivity direction, which allows using this information in predicting the productive qualities and genetic potential of crosses and breeds involved in breeding work, including in the comparative aspect. In addition, these data expand the concept of histogenesis of skeletal muscles in various representatives of poultry and can be basic in the issues of their assessment by morphological indicators in certain periods of life.

Особенности эмбрионального развития скелетных мышц у кур пород Брама и Юрловская голосистая

The article presents the histological and morphological characteristics of skeletal muscles (quadriceps femoris and superficial pectoral muscle) in meat (Brama) and egg (Yurlovskaya golosistaya) chickens of productivity on the 14th day of embryonic development: formed muscle fibers combined in bundles, as well as endomysium and perimysium, in the absence of transverse striation. The quadriceps femoral muscle of the Brama breed (meat productivity direction) surpasses the Yurlovskaya golosistaya (egg productivity direction) due to thicker muscle fibers collected in compact bundles and thin connective tissue components. The superficial pectoral muscle has no significant differences in most of the studied micromorphological parameters (thickness of muscle fibers, endomysium, area of muscle tissue and the number of muscle fibers in the field of view) in both breeds of chickens. The exception is the thickness of the bundles of muscle fibers in the superficial pectoral muscle of the Brama compared to the Yurlovskaya golosistaya, as well as a well-developed perimysium. The results obtained are basic in the formation of the concept of histogenesis of skeletal muscles in the embryonic period of development of the organism of poultry of various productivity directions and can be used.

Prenatal exposure to the phthalate DEHP impacts reproduction-related gene expression in the pituitary

Phthalates are chemicals used in products including plastics, personal care products, and building materials, leading to widespread contact. Previous studies on prenatal exposure to Di-(2-ethylhexyl) phthalate (DEHP) in mice and humans demonstrated pubertal timing and reproductive performance could be affected in exposed offspring. However, the impacts at the pituitary, specifically regarding signaling pathways engaged and direct effects on the gonadotropins LH and FSH, are unknown. We hypothesized prenatal exposure to DEHP during a critical period of embryonic development (e15.5 to e18.5) will cause sex-specific disruptions in reproduction-related mRNA expression in offspring’s pituitary due to interference with androgen and aryl hydrocarbon receptor (AhR) signaling. We found that prenatal DEHP exposure in vivo caused a significant increase in Fshb specifically in males, while the anti-androgen flutamide caused significant increases in both Lhb and Fshb in males. AhR target gene Cyp1b1 was increased in both sexes in DEHP-exposed offspring. In embryonic pituitary cultures, the DEHP metabolite MEHP increased Cyp1a1 and Cyp1b1 mRNA in both sexes and Cyp1b1 induction was reduced by co-treatment with AhR antagonist. AhR reporter assay in GHFT1 cells confirmed MEHP can activate AhR signaling. Lhb, Fshb and Gnrhr mRNA were significantly decreased in both sexes by MEHP, but co-treatment with AhR antagonist did not restore mRNA levels in pituitary culture. In summary, our data suggest phthalates can directly affect the function of the pituitary by activating AhR signaling and altering gonadotropin expression. This indicates DEHP’s impacts on the pituitary could contribute to reproductive dysfunctions observed in exposed mice and humans.

Norepinephrine regulates osteogenesis in the embryonic period of development

Sympathetic and sensory nerve fibers regulate osteosynthesis and osteoresorption processes throughout life. Fundamental research and clinical data confirm the existence of functional interactions between neurons and bone tissue cells and indicate the catabolic and anabolic effect of sympathetic nervous system mediators on bone tissue. There is practically no information about the regulation of osteoremodeling in embryogenesis. Objective: to study the effect of norepinephrine on the growth of bone tissue explants in the embryonic period of development. The studies were performed on the bone tissue explants of 12-day old chicken embryos. Norepinephrine (10-10 M - 10-4 M), propranolol (10-10 M), atenolol (10-4 M), urapidil (10-6 M) were added to the experimental Petri dishes. Norepinephrine (10-6 M) stimulates the growth of the bone tissue explants through α1-adrenoreceptors. The osteotoxic effect of high doses of the drug is realized through β2-adrenoreceptors. Embryonic osteogenesis is regulated by norepinephrine in dose-dependent manner. Physiological effect of the substance depends on the interaction with certain types of adrenoreceptors.

Challenges of stem cell application in research and clinical practice – an update

Abstract There are multiple possible applications of stem cells in medicine, from cell-based therapies for degenerative and dystrophic conditions, through novel approaches in cancer treatment, to in vitro organ printing. However, there are still several challenges that need to be overcame before stem cells therapies can be successfully introduced worldwide on a large scale. These include sourcing of stem cells, preventing their aberrant progression and ethical concerns regarding their use in animals and humans. Among the multiple stem cell types present in the human organism from the period of embryonic development to adulthood, this review focuses on the three types that gain the most attention in relation to modern research: embryonic stem cells, induced pluripotent stem cells and adult stem cells. There are a number of obstacles that need to be removed before these cells can be widely applied in clinical practice, including the choice of the perfect source of stem cells, full elucidation of the mechanisms of stem cell differentiation and plasticity, and minimization of adverse side effect potential. Nonetheless, the focus of the scientific community on the topic of stem cells remains unhindered, bringing hope that all of the possible concerns will be addressed in the future.

PSIX-11 Bacterial clinical mastitis associated with abortion in dairy cows

Abstract Within the period from 20.04.2020 to 15.02.2021 the state of 2087 pregnant cows was studied to identify the connection between abortions and the occurrence of mastitis. During the study period 97 cases of clinical mastitis and 149 cases of abortion were identified. Abortions were observed in 42 out of 97 cows with registered clinical mastitis. It was found that cows that had a clinical form of mastitis during the first 45 days of pregnancy (in the embryonic period of development) subsequently had the maximum number of abortions - 27 heads or 64.28% of abortions of cows with mastitis. Among cows that had mastitis in the period of 46–150 days of pregnancy 13 cases of abortion were revealed (30.9% of abortions of cows with mastitis). Among cows that had mastitis during pregnancy for more than 150 days 2 cases of abortion were detected (4.7% of abortions of cows with mastitis). On the basis of bacteriological analysis, Staphylococcus spp., Streptococcus spp. and Enterobacteriaceae were isolated from milk of 15 aborted cows with the diagnosis of clinical mastitis. To identify species the conventional biochemical methods were applied together with the API 20 E, API Staph, API 20 Strep test (bioMerieux SA, France). In total, 18 species of pathogens were identified, including Ps. aeruginosa (n = 5), E. coli (n = 4), S. aureus (n = 1), S. saprophyticus (n = 8). Ps. aeruginosa, E. coli, S. aureus were isolated both from the organs of the reproductive system and from the milk of the cows who had had abortions after suffering from mastitis, whereas no relationship was found between the microflora of the reproductive system and the udder of the cows whose abortions are not associated with mastitis. The study was supported by the Russian Science Foundation, project No.20-16-00106

Effect of Thermal Manipulation During Embryonic Development on Internal and External Quality Characteristic of Quail Eggs

انتشر إنتاج بيض الفري في الآونة الأخيرة بشكل جيد كمصدر من مصادر البروتين الحيواني لسد احتياجات المستهلكين من هذا البروتين، إضافة للمواصفات التي يتميز بها كمحتواه من البروتينات والفيتامينات والعناصر المعدنية مقارنة ببيض الدجاج. هدف البحث إلى تقييم المواصفات النوعية الداخلية والخارجية لبيض أمات الفري الناتجة من بيض منابل حرارياً أثناء مراحل مختلفة من الحضانة، ومعرفة مدى تأثير برامج المنابلة في مواصفات البيضة ونوعيتها. وُزعت 200 بيضة عشوائياً إلى أربع مجموعات متساوية. حُضّنت بيضات المجموعة الأولى تحت الشروط القياسية لتفريخ بيض الفري، وعُرّضت بيضات المجموعات الثلاثة الأخرى لدرجة حرارة 41° س لمدة 3 ساعات يومياً لمدة 3 أيام متتالية في مراحل مختلفة من التطور الجنيني (مرحلة التطور الجنيني المبكرة – المتأخرة – المزدوجة). جُمعت 40 بيضة بشكل عشوائي بمعدل 10 بيضات من طيور كل مجموعة بهدف دراسة مؤشرات المواصفات النوعية الداخلية والخارجية لبيضة الفري. أظهرت النتائج تفوق مجموعة المنابلة الحرارية أثناء مرحلة التطور الجنيني المتأخر على مجموعة الشاهد بدلالات إحصائية (p<0.05) في معظم المؤشرات المدروسة، أما مجموعة المنابلة أثناء مرحلة التطور الجنيني المبكر فقد كان هناك أفضلية لها (p<0.05) في وزن البيضة ووزن البياض مقارنة بالشاهد. يمكن القول إن الأمات الناتجة عن بيضات منابلة حرارياً وفق هاتين المجموعتين تضع بيضات ذات جودة أفضل.

Temporal Transcriptome Analysis Reveals Dynamic Expression Profiles of Gametes and Embryonic Development in Japanese Flounder (Paralichthys olivaceus).

The maternal-to-zygotic transition (MZT) is a crucial event in embryo development. While the features of the MZT across species are shared, the stage of this transition is different among species. We characterized MZT in a flatfish species, Japanese flounder (Paralichthys olivaceus). In this study, we analyzed the 551.57 GB transcriptome data of two types of gametes (sperms and eggs) and 10 embryo developmental stages in Japanese flounder. We identified 2512 maternal factor-related genes and found that most of those maternal factor-related genes expression decreased at the low blastula (LB) stage and remained silent in the subsequent embryonic development period. Meanwhile, we verified that the zygotic genome transcription might occur at the 128-cell stage and large-scale transcription began at the LB stage, which indicates the LB stage is the major wave zygotic genome activation (ZGA) occurs. In addition, we indicated that the Wnt signaling pathway, playing a diverse role in embryonic development, was involved in the ZGA and the axis formation. The results reported the list of the maternal genes in Japanese flounder and defined the stage of MZT, contributing to the understanding of the details of MZT during Japanese flounder embryonic development.

The effectiveness of soaking Moringa leaves (Moringa oleifera L) on the internal quality of chicken eggs Gallus gallus domestica

The purpose of this study was to analyze the effectiveness of soaking eggs using a solution of Moringa leaves for 24 hours on the internal quality of broiler eggs. Soaking aims to provide a layer on the pores of the egg shell so that it can keep the eggs from microbes and inhibit the release of gas from the egg. This type of research is experimental with Completely Randomized Design (CRD). The number of eggs used is 1000 eggs. The egg samples used are 420 eggs. The eggs used are in good condition, namely brown eggs, clean, intact, not cracked, texture smooth and oval in shape. The randomization method used random sampling in the form of a lottery system. Each of the 420 eggs is labeled. The eggs that were taken at random were divided into 4 treatment groups. Each treatment group consisted of 5 replications. Therefore, 20 treatment replications were obtained. Measurement of storage time and internal quality of eggs will be tested for 21 days. This is done to determine the level of egg resistance accurately, because the embryonic development period of the egg occurs for 21 days. Egg parameter measurements were carried out every day, at 08.00 WITA. Egg quality parameters were taken every 7 days. Egg quality parameters analyzed were egg white index, egg yolk index, and egg weight loss. All measurement data were analyzed by analysis of variance (ANOVA). If the results of the analysis have an effect, the Tukey test is continued with 95% confidence (α> 0.05). The data that has been analyzed explains that chicken eggs that get soaked in a solution of Moringa leaves have a higher index of egg yolk and egg white than eggs that are not soaked in a solution of Moringa leaves. The most optimal concentrations in maintaining the egg yolk and egg white index are 30% and 45% Therefore, soaking eggs with Moringa leaves serves to maintain the internal quality of eggs seen from the yolk index and egg white index.

Choline acts during preimplantation development of the bovine embryo to program postnatal growth and alter muscle DNA methylation.

The preimplantation period of embryonic development can be a key window for programming of postnatal development because extensive epigenetic remodeling occurs during this time. It was hypothesized that modification of one-carbon metabolism of the bovine embryo by addition of the methyl-donor choline to culture medium would change postnatal phenotype through epigenetic modification. Embryos produced in vitro were cultured with 1.8mM choline chloride or control medium. Blastocysts were transferred into females and pregnancy outcomes and postnatal phenotype of the resultant calves determined. Exposure of embryos to choline increased gestation length and calf birth weight. Calves derived from choline-treated embryos were also heavier at weaning and had increased ratio of body weight to hip height than control calves. Choline altered muscle DNA methylation of calves 4 months after birth. A total of 670 of the 8149 CpG examined were differentially methylated, with the predominant effect of choline being hypomethylation. Among the genes associated with differentially methylated CpG were ribosomal RNAs and genes in AMPK, mTOR, integrin, and BEX2 canonical pathways and cellular functions involved in growth and proliferation. Results demonstrate that provision of the methyl-donor choline to the preimplantation embryo can alter its developmental program to increase gestation length, birth weight, and weaning weight and cause postnatal changes in muscle DNA methylation including those associated with genes related to anabolic processes and cellular growth. The importance of the nutritional status of the embryo with respect to one-carbon metabolism for ensuring health and well-being after birth is emphasized by these observations.

Seasonal fitness parameters and selection indices in the natural population of Drosophila melanogaster Meig.

Aim. The purpose of investigation was to study the seasonal selection indices and its components in the natural population of Drosophila melanogaster Meig. Methods. The material for the study was the Gaidary-spring and Gaidary-autumn lines, obtained from the natural population of Gaidary in different seasons of the year. Fecundity and mortality/survival rates in the pre-reproductive period of development were studied. Based on these indicators, the selection indices were calculated according to the Crow`s formula. Results. In terms of individual components of fitness, such as egg production of females, the number of adult offspring, embryonic and pupal mortality, the spring and autumn populations of Gaidary did not show significant differences. Selection indices (Itot) in the autumn population of Gaidary were higher than in the spring population: in the embryonic period of development – by 50.4%, in the postembryonic period – by 67.5%. Differences in the intensity of selection are due to the variance of fertility, which was higher in the autumn population. Conclusions. Seasonal changes in the intensity of selection in different periods of ontogenesis are cumulative, which leads to increased selection pressure in the population of Gaidary in the autumn compared to spring.
 Keywords: Drosophila melanogaster Meig., natural population, fecundity, embryonic mortality, pupal mortality, Crow’s indices.

FGF18 modulates CTGF mRNA expression in cumulus-oocyte complexes and early bovine embryos: preliminary data.

The Hippo pathway is involved in the proliferation of intrafollicular cells and in early embryonic development, mainly because effectors of this pathway are key transcription regulators of genes such as CTGF and CYR61, which are involved in cell proliferation. Recent studies by our group found that fibroblast growth factor 18 (FGF18) is present in the fallopian tube during early embryonic development, leading to the hypothesis that FGF18 may have a role during embryonic development. Therefore, the aim of the following study was to determine whether FGF18 modulates the expression of Hippo pathway target genes, CTGF and CYR61, during oocyte maturation and early embryonic development. Three experiments were carried out, with in vitro maturation (IVM) of cumulus-oocyte complexes (COCs) and embryo culture. In experiment one, FGF18 (100 ng/ml) induced an increase (P < 0.05) in CTGF gene expression at 12 h post-exposure. In experiment two, FGF18 (100 ng/ml) induced a reduction (P < 0.05) in CTGF expression at 3 h post-exposure. In the third experiment, day 7 embryos exposed to FGF18 during oocyte IVM expressed greater CTGF mRNA abundance, whereas FGF18 exposure during embryo in vitro embryo culture did not alter CTGF expression in comparison with untreated controls. The preliminary data presented here show that FGF18 modulates CTGF expression in critical periods of oocyte nuclear maturation, cumulus expansion and early embryonic development in cattle.

Developmental changes of the digestive capacity and hormones levels in developing embryos and yolk‐sac larvae of tongue sole, Cynoglossus semilaevis

Developmental changes in enzymatic activities of alkaline phosphatase (AKP), acid phosphatase (ACP), amylase (AMY), pyruvate kinase (PK), Leucine aminopeptidase N (LAP), Lipase (LIP), Glutamic oxalo acetic transaminase (GOT), Lactate dehydrogenase (LDH), Chymotrypsin (CHY) and Trypsin (TRY) and levels of thyroid hormones and cortisol were measured in developing embryos and yolk-sac larvae of tongue sole, Cynoglossus semilaevis. During embryonic developmental periods, the fastest growth occurred in blastula stage and hatching appeared at 38.8 hours after fertilization (HAF). Besides PK which appeared in cleavage stage onwards, the other enzymes were observed in fertilized egg. Changeable patterns of enzymatic activities presented five types including upward trend for AMY and CHY, M-shaped trend for LIP and PK, V-shaped trend for LAP and GOT, W-shaped trend for LDH and TRY, and an oscillation trend for ACP and AKP. As for hormones, patterns were M-shaped trend for T3, oscillation trend for T4 and downward trend for cortisol. Furthermore, LDH, LIP, PK, TRY, ACP, GOT and T4 showed relatively high levels in blastula stage, which may be an important factor leading to the most rapid growth of embryo. Regression analysis revealed that AMY, GOT and ACP were significantly correlated with embryonic mass, which may provide an effective way to evaluate development of embryos. During yolk-sac larval periods, mouth-opening day appeared at 3 days after hatching (DAH). Besides LAP, GOT, T4 and cortisol which showed downward tendency, the other enzymes and T3 displayed upward tendency and reached the peak at 3 DAH, preparing well for upcoming exogenous digestion.

Mercury Toxicity and Neurogenesis in the Mammalian Brain

The mammalian brain is formed from billions of cells that include a wide array of neuronal and glial subtypes. Neural progenitor cells give rise to the vast majority of these cells during embryonic, fetal, and early postnatal developmental periods. The process of embryonic neurogenesis includes proliferation, differentiation, migration, the programmed death of some newly formed cells, and the final integration of differentiated neurons into neural networks. Adult neurogenesis also occurs in the mammalian brain, but adult neurogenesis is beyond the scope of this review. Developing embryonic neurons are particularly susceptible to neurotoxicants and especially mercury toxicity. This review focused on observations concerning how mercury, and in particular, methylmercury, affects neurogenesis in the developing mammalian brain. We summarized information on models used to study developmental mercury toxicity, theories of pathogenesis, and treatments that could be used to reduce the toxic effects of mercury on developing neurons.

Research progress on reproductive biology of important economic shrimps of Palaemonoidea

Palaemonoidea is one of the most important economic shrimps in China, belonging to Caridea, Decapoda, Crustacea. Reproductive biology mainly focuses on the information related to species reproduction, especially to shrimp artificial breeding. At present, <italic>Macrobrachium rosenbergii</italic>, <italic>Macrobrachium nipponense</italic> and <italic>Exopalaemon carinicauda</italic> have been comprehensively studied and cultured on a large scale. There are still a large number of species to be explored in Palaemonoidea, such as <italic>Palaemon gravieri</italic>, <italic>Macrobrachium hainanense</italic>, <italic>Exopalaemon modestus</italic> and <italic>Exopalaemon annandalei</italic>, etc. The purpose of this review is to understand the common and unique reproductive habits of species of Palaemonidae, and to compare the differences and similarities of reproductive habits between Penaeidae, Cambarus and Palaemonidae, as the results might provide a scientific basis for the follow-up study of species of Palaemonoidea. We found that shrimps of Palaemonoidea had a long reproductive period, usually from April to October, and there were usually more than one active reproductive period during the reproductive season. They were able to be sexually mature multiple times during the breeding period and participate in reproduction. And they had generally higher sex ratio(usually higher than 1), which ensured the ability of the groups to breed the next generation. In conclusion, the species of Palaemonoidea had strong fecundity. The female reproductive system of species of Palaemonoidea showed no obvious similarity, according to the existing research data. On the contrary, we found that the gonad structure of some species of Palaemonoidea was similar to that of other families. By summarizing and analyzing various viewpoints, we designed a method for the division of embryonic development period, which might be more reasonable and scientific. There were eight stages in the embryonic development of Palaemonoidea shrimp, which were fertilized egg stage, cleavage stage, blastocyst stage, gastrula stage, pre nauplius stage, post nauplius stage, pro zoea stage and intramembranous zoea stage. After eight periods of development, the larvae hatched from the mother. Due to the weak motility and predation ability of early larvae, the residual yolk was the main source of nutrition. Then the movement ability and predation ability of the larvae gradually formed and improved, and they could start to filter and feed on all kinds of algae. The whole development process was affected by many environmental factors, such as temperature, salinity and pH value. In addition, a variety of genes have been found to participate in the reproductive process of species of Palaemonoidea. Among these, genes related to gonadogenesis, sexual differentiation, development of embryo and larvae, molt, immunity process have been reported, and these genes play important roles in reproduction by affecting group sex ratio, survival rate and growth rate of embryo larvae.

Schwann cell precursors generate sympathoadrenal system during zebrafish development.

The autonomic portion of the peripheral nervous system orchestrates tissue homeostasis through direct innervation of internal organs, and via release of adrenalin and noradrenalin into the blood flow. The developmental mechanisms behind the formation of autonomic neurons and chromaffin cells are not fully understood. Using genetic tracing, we discovered that a significant proportion of sympathetic neurons in zebrafish originates from Schwann cell precursors (SCPs) during a defined period of embryonic development. Moreover, SCPs give rise to the main portion of the chromaffin cells, as well as to a significant proportion of enteric and other autonomic neurons associated with internal organs. The conversion of SCPs into neuronal and chromaffin cells is ErbB receptor dependent, as the pharmacological inhibition of the ErbB pathway effectively perturbed this transition. Finally, using genetic ablations, we revealed that SCPs producing neurons and chromaffin cells migrate along spinal motor axons to reach appropriate target locations. This study reveals the evolutionary conservation of SCP-to-neuron and SCP-to-chromaffin cell transitions over significant growth periods in fish and highlights relevant cellular-genetic mechanisms. Based on this, we anticipate that multipotent SCPs might be present in postnatal vertebrate tissues, retaining the capacity to regenerate autonomic neurons and chromaffin cells.

Artificial propagation and embryonic growth in Stinging catfish, Heteropneustes fossilis (Bloch, 1794) using S-GnRHa (salmon gonadotropin releasing hormone analogue)

An experiment was performed to observe the potentiality of synthetic hormone analogue in artificial propagation i.e., the embryonic and larval development of Heteropneustes fossilis. Broodfish were injected with S-GnRHa according to the following concentration: 1, 2.5 and 5 ml kg-1 of body weight (BW) to females and 0.5, 1.125 and 2.5 ml kg-1 BW to males, in treatment groups T1, T2 and T3, respectively each with three replicates. The fishes were ovulated at about 10-11 hours after the hormone injection. Result showed the highest fertilization (83.11±1.36) and hatching rate (89.56±1.04) in T2, whereas ovulation rate was 100% in all treatment groups. First cleavage was observed in 30 minutes of post-fertilization. Embryonic developmental period sequentially for 2-cell, 4-cell, 8-cell, 16-cell, 32-cell, 64-cell, Morula, Blastula, Gastrula, somatic formation, yolk-plug, twisting movement and pre-hatching were 00:30, 00:45, 01:10, 01:30, 02:00, 02:30, 03:00, 04:00, 06:40, 09:00-18:00, 19:00, 20:00-21:00 and 22:00 hours, respectively. Hatching occurred after 23:00 hours of fertilization. Finally, the current result suggested that S-GnRHa might be an effective synthetic hormone in artificial propagation of H. fossilis.

Amblypygi parthenogenesis, embryonic and post-embryonic development: a case study with the Amazonian species Charinus guto Giupponi and Miranda, 2016 (Amblypygi: Charinidae)

ABSTRACT Parthenogenesis is documented in a few species of Amblypygi, but it is unknown how widespread in the order this reproductive behaviour is, and little has been researched regarding aspects of embryonic and post-embryonic development in the group. Here, we studied the parthenogenetic capacity of an Amazonian whip spider (Charinus guto) evaluating the time of egg and embryonic development and inter-moult period. We also provide a review on embryonic and post-embryonic development in Amblypygi, compiling and analysing data from 43 species in three families. Fifty-two females and 42 juveniles of C. guto were collected in fragments of a secondary forest in Belém (Brazil); specimens were kept in captivity and observed weekly from 2018 to 2020. Nineteen specimens were collected with and 32 without egg sacs. Fourteen of the non-ovigerous females developed eggs in captivity, six of them moulted (i.e. lost stored sperm from previous contacts with males) before developing an egg sac, proving to be parthenogenetic. The mean time between the first day in captivity and moult was 96 days. In both adults and juveniles, a mean of 147 days passed between first day in captivity and first moult, and 125 days for a second moult. After moulting, a mean of 113 days passed for the females to develop an egg sac; the embryonic development took a mean of 59 days. Juveniles left the mother’s abdomen after 10 days of hatching from the egg and the mean number of live free-living protonymphs was five. Other amblypygids, especially charinids, have similar embryonic development and post-embryonic growth and a detailed discussion with all known information for whip spiders is presented. We also demonstrate a positive correlation between clutch size and female size across Amblypygi, in which larger females carry more eggs and have larger offspring regardless of climate and habitat.

Prenatal Exposure to the Endocrine Disrupting Chemical DEHP Impacts Reproduction-Related Gene Expression in the Pituitary

Abstract Phthalates are chemicals used in various common products including plastics and medical devices, leading to widespread contact. Phthalate exposure during embryonic development can cause changes in puberty timing, reduced fertility and genital abnormalities. Previous studies on prenatal exposure to Di-(2-ethylhexyl) phthalate (DEHP) in mice indicated that it disrupts pituitary-gonadal feedback and alters reproductive performance in the offspring, however, the mechanism behind this is unknown. We hypothesize that prenatal exposure to DEHP during a critical period of embryonic development (e15.5 to e18.5) will cause sex-specific disruptions in reproduction-related functions in the pituitary in offspring due to interference with androgen and aryl hydrocarbon receptor (AhR) signaling. In order to discover the direct effects of DEHP on the reproduction-related functions in the pituitary, we performed both in vivo dosing and in vitro pituitary culture experiments. First, we dosed pregnant CD-1 mice with corn oil, the antiandrogen flutamide or DEHP from gestational day 15.5 to 18.5, then collected the pituitaries of the offspring on postnatal day 0. We found that prenatal DEHP exposure caused a significant increase in Fshb specifically in males, and flutamide caused significant increases in both Lhb and Fshb in males. Besides, DEHP exposure significantly increased AhR pathway related gene Cyp1b1 in both males and females. In the in vitro experiment, we took whole pituitaries from e16.5 embryos and cultured them in media containing DEHP, MEHP and/or AhR antagonist for 72hrs. We found that the DEHP metabolite MEHP was actually the chemical that exerted the effects directly at the level of the pituitary. Similar to in vivo experiments, Cyp1a1 and Cyp1b1 mRNA level were increased in pituitaries treated with MEHP in both sexes and the induction could be reduced by co-treatment with AhR antagonist. The mRNA level of Lhb, Fshb and Gnrhr were significantly decreased in both sexes by MEHP and co-treatment with AhR antagonist did not restore mRNA levels. The induction of Cyp1a1/Cyp1b1 gene in both in vivo and in vitro experiments indicates the possible activation of AhR by DEHP/MEHP. The in vitro experiment with AhR antagonist further proved that the induction of Cyp1a1/Cyp1b1 was indeed due to AhR activation directly at the level of the pituitary. The difference between in vivo and in vitro experiments in terms of gonadotropin gene expression indicates multiple mechanisms should be involved in the regulation of gonadotropin gene expression in vivo including androgen-related pathways and possibly AhR-related pathways. In summary, our data suggest that phthalates can directly affect the function of the pituitary in terms of regulation of reproductive- related genes. This indicates that pituitary impacts of phthalates could contribute to reproductive dysfunction observed in exposed mice and humans.

The ALK inhibitors, alectinib and ceritinib, induce ALK‐independent and STAT3‐dependent glioblastoma cell death

Glioblastoma (GBM) is the most common, but extremely malignant, brain tumor; thus, the development of novel therapeutic strategies for GBMs is imperative. Many tyrosine kinase inhibitors (TKIs) have been approved for various cancers, yet none has demonstrated clinical benefit against GBM. Anaplastic lymphoma kinase (ALK) is a receptor tyrosine kinase (RTK) that is confirmed only during the embryonic development period in humans. In addition, various ALK gene alterations are known to act as powerful oncogenes and therapeutic targets in various tumors. The antitumor activity of various TKIs was tested against three human GBM cell lines (U87MG, LN229, and GSC23), which expressed substantially low ALK levels; second‐generation ALK inhibitors, alectinib and ceritinib, effectively induced GBM cell death. In addition, treatment with either alectinib or ceritinib modulated the activation of various molecules downstream of RTK signaling and induced caspase‐dependent/‐independent cell death mainly by inhibiting signal transducer and activator of transcription 3 activation in human GBM cells. In addition, alectinib and ceritinib also showed antitumor activity against a U87MG cell line with acquired temozolomide resistance. Finally, oral administration of alectinib and ceritinib prolonged the survival of mice harboring intracerebral GBM xenografts compared with controls. These results suggested that treatment with the second‐generation ALK inhibitors, alectinib and ceritinib, might serve as a potent therapeutic strategy against GBM.