Period Of Embryonic Development Research Articles

Clinical and genetic characteristics of type 3 lissencephaly caused by a mutation in the TUBA1A gene (OMIM: 611603)

Background. Lissencephaly (LIS) is a spectrum of malformations of the cerebral cortex that occur as a result of impaired migration of neuronal precursors to the cortical plate and the formation of furrows and convolutions in the post‑migration period of embryonic development. In recent years, a significant role of hereditary factors in the occurrence of LIS has been shown due to the improvement of methods of molecular genetic diagnostics. Today, 13 genetic variants have been identified in the LIS group, six of which are inherited autosomal recessively, five are autosomal dominant, and two are linked to the X chromosome. It is shown that 80 % of cases of hereditary LIS is caused by mutations in two genes: PAFAH1B1 , which is responsible for the occurrence of the LIS 1 type with an au‑ tosomal dominant type of inheritance, and in the DCX gene, localized on the X chromosome. The rest of the genetic variants account for from 1 % to 5 % of cases of defects accompanied by dysgenesis of the cerebral cortex. In recent years, the number of works devoted to the analysis of clinical and genetic characteristics of monogenic variants of LIS has increased. The results of such studies will allow us to improve our understanding not only of the pathogenetic mechanisms of this group of diseases, but also of the molecular basis for the formation of brain structures in the normal embryonic period. Objective: to describe the clinical and genetic characteristics of three Russian patients with autosomal dominant LIS type 3 (OMIM: 611603) caused by mutations in the TUBA1A gene. Materials and methods. All patients were under observation in the consultative and diagnostic department of Research Centre for Medical Genetics. The diagnosis was established on the basis of clinical data, genealogical anamnesis, results of brain MRI, EEG night video monitoring and exome sequencing by NGS. The validation of the identified nucleotide substitutions and analysis of the disease segregation were performed using the Sanger direct automatic sequencing method. Results. The clinical and genetic characteristics of three patients with newly identified and previously described mutation in the TUBA1A gene were analyzed. Possible effects of new missense mutations in the gene on the function of the protein product of the gene are discussed. Conclusions. The results of the analysis of the clinical and genetic characteristics of the patients we observed contribute to the study of the polymorphism of clinical manifestations resulting from mutations in the TUBA1A gene. The previously stated assumption about a wide range of malformations of the brain in patients with mutations in this gene was confirmed, which should be taken into account when making a diagnosis.

Small RNA sequencing provides candidate miRNA-target pairs for revealing the mechanism of apomixis in Zanthoxylum bungeanum

BackgroundApomixis is a form of asexual reproduction that produces offspring without the need for combining male and female gametes, and the offspring have the same genetic makeup as the mother. Therefore, apomixis technology has great application potential in plant breeding. To identify the apomixis types and critical period, embryonic development at different flower development stages of Zanthoxylum bungeanum was observed by cytology.ResultsThe results show that the S3 stage is the critical period of apomixis, during which the nucellar cells develop into an adventitious primordial embryo. Cytological observations showed that the type of apomixis in Z. bungeanum is sporophytic apomixis. Furthermore, miRNA sequencing, miRNA-target gene interaction, dual luciferase reporter assay, and RT-qPCR verification were used to reveal the dynamic regulation of miRNA-target pairs in Z. bungeanum apomixis. The miRNA sequencing identified 96 mature miRNAs, of which 40 were known and 56 were novel. Additionally, 29 differentially expressed miRNAs were screened according to the miRNAs expression levels at the different developmental stages. Kyoto Encyclopedia of Genes and Genomes (KEGG) and Gene Ontology (GO) enrichment analyses showed that the target genes of the differentially expressed miRNAs were mainly enriched in plant hormone signal transduction, RNA biosynthetic process, and response to hormone pathways.ConclusionsDuring the critical period of apomictic embryonic development, miR172c significantly reduces the expression levels of TOE3 and APETALA 2 (AP2) genes, thereby upregulating the expression of the AGAMOUS gene. A molecular regulation model of miRNA-target pairs was constructed based on their interactions and expression patterns to further understand the role of miRNA-target pairs in apomixis. Our data suggest that miR172c may regulates AGAMOUS expression by inhibiting TOE3 in the critical period of apomixis.

Effect of serotonin on myocardial contractility in newborn rats with excess and deficiency of serotonin in the embryonic period

Serotonin as a neurotransmitter (5-HT) plays a crucial role in the cardiovascular system. Serotonin is a humoral system of regulators and modulators of physiological processes. Under pathological conditions, these processes can turn into factors contributing to the development of diseases such as atherosclerosis, arterial hypertension, and pulmonary hypertension. The 5-HT4 and 5-HT2B receptors are found in cardiomyocytes. During the embryonic period, serotonin acts as a growth factor and plays an important regulatory role in the crucial period of embryonic development, in particular, a heart of an embryo. Therefore, any interference with this system in the womb can disrupt the normal development of the cardiovascular system. In the given study, there is some data provided to indicate that a change in the serotonin concentration created by the serotonin synthesis and the membrane serotonin transporter blocked in the embryonic period of ontogenesis, affects the inotropic function of the right ventricular myocardium in early postnatal ontogenesis, which is caused by a change in the contraction time in the groups under the experiment. Thus, statistically the response of cardiomyocytes to serotonin is significantly higher in the group with an excess of serotonin and significantly lower in the group with a deficiency of serotonin compared to the control group.

Neurospheres: a potential in vitro model for the study of central nervous system disorders.

Neurogenesis was believed to end after the period of embryonic development. However, the possibility of obtaining an expressive number of cells with functional neuronal characteristics implied a great advance in experimental research. New techniques have emerged to demonstrate that the birth of new neurons continues to occur in the adult brain. Two main rich sources of these cells are the subventricular zone (SVZ) and the subgranular zone of the hippocampal dentate gyrus (SGZ) where adult neural stem cells (aNSCs) have the ability to proliferate and differentiate into mature cell lines. The cultivation of neurospheres is a method to isolate, maintain and expand neural stem cells (NSCs) and has been used extensively by several research groups to analyze the biological properties of NSCs and their potential use in injured brains from animal models. Throughout this review, we highlight the areas where this type of cell culture has been applied and the advantages and limitations of using this model in experimental studies for the neurological clinical scenario.

Iron overload during the embryonic period develops hyperactive like behavior and dysregulation of biogenic amines in Drosophila melanogaster

Iron (Fe) is used in various cellular functions, and a constant balance between its uptake, transport, storage, and use is necessary to maintain its homeostasis in the body. Changes in Fe metabolism with a consequent overload of this metal are related to neurological changes and cover a broad spectrum of diseases, mainly when these changes occur during the embryonic period. This work aimed to evaluate the effect of exposure to Fe overload during the embryonic period of Drosophila melanogaster. Progenitor flies (male and female) were exposed to ferrous sulfate (FeSO4) for ten days in concentrations of 0.5, 1, and 5 ​mM. After mating and oviposition, the progenitors were removed and the treatment bottles preserved, and the number of daily hatches and cumulative hatching of the first filial generation (F1) were counted. Subsequently, F1 flies (separated by sex) were subjected to behavioral tests such as negative geotaxis test, open field test, grooming, and aggression test. They have evaluated the levels of dopamine (DA), serotonin (5-HT), octopamine (OA), tryptophan and tyrosine hydroxylase (TH), acetylcholinesterase, reactive species, and the levels of Fe in the progenitor flies and F1. The Fe levels of F1 flies are directly proportional to what is incorporated during the period of embryonic development; we also observed a delay in hatching and a reduction in the number of the hatch of F1 flies exposed during the embryonic period to the 5mM Fe diet, a fact that may be related to the reduction of the cell viability of the ovarian tissue of progenitor flies. The flies exposed to Fe (1 and 5 ​mM) showed an increase in locomotor activity (hyperactivity) and a significantly higher number of repetitive movements. In addition to a high number of aggressive encounters when compared to control flies. We can also observe an increase in the levels of biogenic amines DA and 5-HT and an increase in TH activity in flies exposed to Fe (1 and 5 ​mM) compared to the control group. We conclude that the hyperactive-like behavior demonstrated in both sexes by F1 flies exposed to Fe may be associated with a dysregulation in the levels of DA and 5-HT since Fe is a cofactor of TH, which had its activity increased in this study. Therefore, more attention is needed during the embryonic development period for exposure to Fe overload.

Studies of the Effects of Monoamines on Orexinergic Neurons in the Hypothalamus of Rat Embryos

Hypothalamic orexinergic neurons are involved in controlling various body functions, particularly energy balance, feeding behavior, wakefulness, and awakening. The direct effects of brain dopamine and serotonin on orexinergic neurons in the hypothalamus are mediated via various subtypes of the corresponding receptors, whose expression has previously been demonstrated in the bodies of orexinergic neurons. Studies were performed on 18-day rat embryos to assess the possibility that these interactions form during the embryonic period of development. Western blotting was used to demonstrate expression of dopamine D1 and serotonin 2C receptor proteins in the developing hypothalamus. Studies using double fluorescence immunolabeling and confocal microscopy confirmed the expression of dopamine D1 and serotonin 2C receptors in the bodies of developing orexin-immunopositive cells in rat embryos. These results provide evidence that the development of morphofunctional interactions between the monoaminergic systems and the orexinergic system occur during the embryonic period of development.

EDCs Reorganize Brain-Behavior Phenotypic Relationships in Rats.

All species, including humans, are exposed to endocrine-disrupting chemicals (EDCs). Previous experiments have shown behavioral deficits caused by EDCs that have implications for social competence and sexual selection. The neuromolecular mechanisms for these behavioral changes induced by EDCs have not been thoroughly explored. Here, we tested the hypothesis that EDCs administered to rats during a critical period of embryonic brain development would lead to the disruption of normal social preference behavior, and that this involves a network of underlying gene pathways in brain regions that regulate these behaviors. Rats were exposed prenatally to human-relevant concentrations of EDCs (polychlorinated biphenyls [PCBs], vinclozolin [VIN]), or vehicle. In adulthood, a sociosexual preference test was administered. We profiled gene expression of in preoptic area, medial amygdala, and ventromedial nucleus. Prenatal PCBs impaired sociosexual preference in both sexes, and VIN disrupted this behavior in males. Each brain region had unique sets of genes altered in a sex- and EDC-specific manner. The effects of EDCs on individual traits were typically small, but robust; EDC exposure changed the relationships between gene expression and behavior, a pattern we refer to as dis-integration and reconstitution. These findings underscore the effects that developmental exposure to EDCs can have on adult social behavior, highlight sex-specific and individual variation in responses, and provide a foundation for further work on the disruption of genes and behavior after prenatal exposure to EDCs.

Congenital abnormalities in dead-in-shell chicks associated with mixed bacterial infections

Determination of the chick embryonic developmental period at which embryonic mortalities occur could help in establishing the cause of such mortalities. The late stage of embryonic development has particular importance due to its dramatic effect on life after hatching. This study was conducted to investigate the occurrence, frequency and bacterial isolates from dead-in-shell chick embryos in Northern Jordan. A total of 1,000 unhatched eggs were collected at hatching day from 10 hatcheries located in Northern Jordan. Out of 1,000 eggs, 357 (35.7%) were fertile, of which 210 (58.8%) were dead-in-shell embryos. Approximately 50.5% of the dead embryos displayed abnormalities, including neck muscles with subcutaneous petechial haemorrhages (44.3%), beak abnormalities (3.8%), eye deformities (1.9%) and anencephaly (0.5%). Sixty-six bacterial isolates were identified from 82 samples from the dead-in-shell embryos. The isolates were 22 (33.3%) Escherichia coli, 18 (27.3%) Klebsiella pneumoniae, 14 (21.2%) Staphylococcus aureus, 5 (7.6%) Pseudomonas aeruginosa, 4 (6.1%) Salmonella enteritidis, 2 (3%) Bacillus cereus and 1 (1.5%) Proteus vulgaris. Mixed growth was also recorded in 16 (19.5%) samples. There was a significant (P < 0.05) association between Escherichia coli as a bacterial isolate and the occurrence of neck and beak abnormalities. In this study, infection of check embryos with several bacterial species, particularly Escherichia coli, was identified as an important cause of multiple congenital abnormalities involving the neck and beak of unhatched chicks.

СРАВНИТЕЛЬНАЯ ХАРАКТЕРИСТИКА МОРФОМЕТРИЧЕСКИХ ПОКАЗАТЕЛЕЙ РОСТА И РАЗВИТИЯ ЭМБРИОНОВ КУР ЯИЧНЫХ КРОССОВ «ХАЙСЕКС КОРИЧНЕВЫЙ» И «ЛОМАНН БРАУН» В РАЗНЫЕ ПЕРИОДЫ ЭМБРИОГЕНЕЗА ПРИ ПЕРЕМЕННЫХ ТЕМПЕРАТУРАХ ИНКУБАЦИИ ЯИЦ

The results of experimental studies on the influence of variable temperatures of egg incubation (37.8°C - 1...14 days; 39.5°C for 2 hours daily - 15-17 days; 37.5°C - 18 days; 37.0 °C - 19-20 days) on the growth and development of chicken embryos of egg crosses "Hisex Brown" and "Lohmann Brown" in different periods of embryogenesis. Under conditions of variable temperature incubation of eggs in the embryos of hens of the Lohmann Brown cross, compared with the Hisex Brown, there was a statistically significant increase in the absolute values of body weight by 12 (p=0.011), 14 (p=0.001), 15 (p= 0.000), 20 (p=0.000) days, body length - on days 6 (p=0.000), 8 (p=0.000), 9 (p=0.025), 13…16 (p=0.000) days. Differences in the rhythm of the growth of chicken embryos were established, accompanied by 5 critical stages of the growth rate of body weight and 6 critical stages of the growth rate of body length in the Haysex Brown cross, and in the embryos of the Lohmann Brown cross - 4 and 1 critical stages, respectively. Throughout the studied period of embryogenesis in the studied crosses, the highest intensity of the growth rate of weight and body length was noted in the embryonic period of development with a decrease towards the hatching period. The highest specific weight growth rate in the embryonic period is typical for embryos of chickens "Hisex Brown" (p=0.000), and body length - for embryos of the cross "Lohmann Brown" (p=0.047). In subsequent periods of embryonic development, the specific rate of growth in body weight and length decreased in both crosses. Differences in the specific rate of body weight growth in embryos of chickens "Hisex Brown" and "Lohmann Brown" in the prefetal (p=0.680) and fetal periods (p=0.477) were not found, and in the specific rate of body length growth - in the prefetal (p= 0.709), fetal periods (p=0.942) and hatching period (p=0.918). By the hatching period, the specific body weight growth rate prevailed in the Lohmann Brown embryos (p=0.000). The effect of exposure to variable incubation temperatures was accompanied by a higher percentage of chick hatchability of the Lohmann Brown cross (94.90%) compared to the Highsex Brown cross (91.90%). The results obtained indicate the feasibility of using the proposed mode of incubation with variable temperatures for cross-country chickens "Lohmann Brown".

Short term temperature fluctuations affect embryonic and larval development of yellow perch (Perca flavescens)

Early life stages of fishes are critical stages due to their importance in enhancing recruitment. Given the high mortality through the embryonic and larval stages, managers have started investigating factors that impact these stages. Environmental factors, such as water temperature, have been found to play a larger role in early life survival. Climate change predications will be more apparent in northern temperate systems like the Great Lakes. Yellow perch Perca flavescens are an important sport fish in the region whose populations have been declining since the 1980s. Yellow perch recruitment is highly erratic due to the species dependence on spring water temperatures. With warming waters occurring earlier in the seasons, it is unsure how wild yellow perch will adapt. The objective of this study was to determine how variations in temperature regimes during the egg incubation period would impact embryonic and larval development in yellow perch. Four different temperature treatments were used in this study: steady temperature at 16°C, a gradient starting at 12°C increasing by 1-2°C every 3-4 days, a heat shock on day six of 20°C for 16 hours to mimic a heat wave event, and finally, a cold shock on day six of 10°C temperatures for 16 hours to mimic a cold snap event. The results of this study confirm that water temperatures severely impact embryonic development and incubation periods of yellow perch, having a significant impact on the percent of failed larvae at the end of the incubation period (P= 0.0005), with the cold shock affecting the lowest percent of failed larvae (0.8%) while the steady treatment had the highest percent (22.9%). Temperature treatment did have a significant impact on the time it took for larvae to successfully hatch out (P&lt;0.001), but no significant effect on observed mortality and estimated mortality (P= 0.96), percent of surviving larvae (P=0.35), or average growth rate of larvae (P=0.16).This study reveals that yellow perch are better adapted to withstand acute cold shifts in water temperature than acute warming events. Climate change could potentially hinder an already struggling Lake Michigan yellow perch population.

Опыт термического мечения отолитов личинок щуки обыкновенной

The article provides a detailed review of the marking methods of juvenile fish and discusses the mechanisms of the microstructure pike otoliths’ formation. The feasibility of thermal otolith marking of larvae and early juvenile fish with a short period of embryonic development is shown on the example of the common pike. The objectives of the study were to determine the most suitable age of pike juveniles for marking, and the optimal duration of temperature exposure. Three marking protocols were tested, in which the water temperature gradient was 7-12 °C, and the exposure time was 5, 6 and 10 hours, respectively. The pike larvae were marked at the age of 4 days and 11 days (after the start of the exogenous feeding) at least four times. The results of marking were evaluated on the first day and on the 10 th day after marking, as well as at later stages of development (in the age of 21-44 days). Most visible marks were noted in short heating cycles (5-6 hours) in larvae before the start of the exogenous feeding.

Expression of Connexins 37, 43 and 45 in Developing Human Spinal Cord and Ganglia.

Direct intercellular communication via gap junctions has an important role in the development of the nervous system, ranging from cell migration and neuronal differentiation to the formation of neuronal activity patterns. This study characterized and compared the specific spatio-temporal expression patterns of connexins (Cxs) 37, 43 and 45 during early human developmental stages (since the 5th until the 10th developmental week) in the spinal cord (SC) and dorsal root ganglia (DRG) using double immunofluorescence and transmission electron microscopy. We found the expression of all three investigated Cxs during early human development in all the areas of interest, in the SC, DRG, developing paravertebral ganglia of the sympathetic trunk, notochord and all three meningeal layers, with predominant expression of Cx37. Comparing the expression of different Cxs between distinct developmental periods, we did not find significant differences. Specific spatio-temporal pattern of Cxs expression might reflect their relevance in the development of all areas of interest via cellular interconnectivity and synchronization during the late embryonic and early fetal period of human development.

HEMATOLOGICAL INDICES AND THE RATE OF GROWTH DEPENDING ON DURATION OF EMBRYONIC GROWTH OF PIGS OBTAINED BY COMMERCIAL CROSS-BREEDING

The studies were performed in pigs obtained by commercial cross-breeding under conditions of pig-breeding complex of Agricultural Open Joint-Stock Company Agrokombinat Kalyta. 115 crossbred breeding sows (Big White x Landras) – of similar age and development – were selected for the study; they were mated with purebred Big White boars. Three groups by five animals were selected from these breeding sows by pregnancy duration. The first one (control group, the pregnancy duration was the farm average) – 112-116 days; the second one (study group, reduced pregnancy duration) – 103-111 days; the third one (study group, extended pregnancy duration) – 117-120 days. The authors studied the growth duration and hematological parameters of these breeding sows’ offsprings after ablactation until the end of fattening. The piglets were ablactated at the age of 26 days. The young stock were fed with dry feed stuff according to the conventional technology. The feed level for the pigs of all groups was the same. The pigs were weighted upon birth at 1, 2, 4, 6 months, and the relative weight gain and actual growth rate of the pigs were determined by Shmalgauzen and Brody formula. Hematological tests were performed at the age of 2, 4 and 6 months in four animals from each group (two gilts and two boars). Blood for tests was collected from auricular veins before feeding. Red blood cell count and hemoglobin concentration were measured by hemascope, total protein, albumin and globulins were measured refractometrically. It has been established that the piglets obtained from the breeding sows with reduced pregnancy duration had the lowest body weight at birth, and the piglets obtained from the extended pregnancy had the highest body weight. From the age of two months, the young stock with the reduced embryonic growth duration were superior to the age-mates with the average and extended pregnancy in terms of body weight. The animals with reduced embryonic growth duration had higher relative weight gain and the actual growth rate factor, which characterizes their high growth intensity. The pigs obtained at commercial cross-breeding with different embryonic development duration had different blood composition. Thus, the piglets with reduced and average embryonic growth duration, had higher red blood cells count, hemoglobin and total protein content. Higher hematological indicators in pigs with reduced embryonic period coincide with the period of their higher growth energy which indicates the interrelation between the intensity of the animals’ growth and the red blood cell count, hemoglobin and total protein in blood. Therefore, the embryonic development period reduction positively affects the growth energy, that is associated with improved hematological indicators, which is advisable to consider in pigs selection program.

PSVIII-16 Interferon-TAU in the pathogenesis and prevention of intrauterine growth restriction and embryonic death in dairy cows

Abstract The aim of the research was to assess the state of the hormonal and cytokine blood profiles of Holstein dairy cows during the early period of gestation with physiological formation of the embryo, its intrauterine growth restriction and death, clarify the pathogenetic mechanisms of these embryopathologies development and identify the efficacy of their prevention using recombinant bovine INFT. The dynamics of serum concentration of P4, cortisol (F) and cytokines: INFT, interleukin IL-2, tumor necrosis factor (TNFα), interferon-γ (INF-γ) at the physiological formation of the embryo (n = 9), its growth restriction (n = 9) and death (n = 8) were studied. The blood samples were obtained on the day of artificial insemination, during early blastogenesis (days 8–9), implantation of the embryo (days 15–16), the formation of primary genital organs (days 32–33), and at the end of the embryonic period of development (days 60–65). In cows with intrauterine growth restriction and embryonic death, serum concentration of P4, compared with the cows demonstrating their physiological formation, was lower by 14.0–30.1%, F - by 11.2–35.5%, INFT - by 21.0–37.7% when the content of IL-2 was exceeded by 46.5–310.5%, TNFα - by 11.7–36.2%, INF-γ - by 58.0–296.0%. A statistically significant positive correlative relationship between the content of INFT, P4, F and a negative one with the indices of the concentration of proinflammatory cytokines was found. Violation of the hormonal-cytokine balance in the organisms of fertilized animals is a universal pathogenetic mechanism for the development of early embryopathies. Injections of recombinant bovine INFT to inseminated cows during the pre- and implantation periods increased the level of progesterone production and reduced the synthesis of proinflammatory cytokines. The efficacy of insemination of cows increased by 1.96 times, the manifestation of fetal/embryonic intrauterine growth restriction syndrome decreased by 2.35 times in comparison with the control animals.

Ontogeny of hepatic methionine catabolic enzyme activities (Transmethylation and Transsulphuration) and associated physiological amino acids in E10-21 chick embryos and D1-49 broilers.

Developmental changes in hepatic methionine adenosyltransferase, cystathionine β-synthase, cystathionase, and glycine N-methyltransferase were determined in broiler chick embryos and hatched chicks by using radiometric and spectrometric methods. Hepatic free methionine, S-adenosylmethionine, S-adenosylhomocysteine, homocysteine, cystathionine, and cysteine levels were also investigated. Results showed an increase in hepatic MAT activity from E10 to E21 during embryogenesis, suggesting greater transmethylation rates throughout the rapid embryonic growth and development period. A strong positive correlation between embryo BW and MAT activity also supports this idea. The MAT specific activity continued to increase after hatching, but there was a negative correlation between chick BW and MAT activities from D1 to D49. This may indicate different MAT isozymes exist for chick embryo hepatic tissue compared to hepatic tissue of hatched chick and growing broilers. The developmental pattern of MAT isozymes could be critical for methionine metabolism to cope with the demand imposed on the embryo, chicks, and growing broilers. Additionally, the specific activity of hepatic CBS in chick embryos was determined to be lower compared to that observed in older broilers (35 and 49days). Since liver CBS specific activity is at the lowest point from D1-7 in young chicks, the ability to convert adequate homocysteine to cysteine through transsulphuration may be limiting for cysteine synthesis at this time. Steady-state hepatic homocysteine levels in chick embryos and chicks may be a function of the rates of homocysteine formation, remethylation, and catabolism via the transsulphuration pathway. The present study indicates young chicks from D1 to D7 may have a limited ability for adequate transsulphuration; therefore, dietary cystine may be needed for optimum performance.

Influence of inoculated gut bacteria on the development of Bactrocera dorsalis and on its susceptibility to the entomopathogenic fungus, Metarhizium anisopliae

BackgroundSymbiotic interactions between insects and bacteria have been associated with a vast variety of physiological, ecological and evolutionary consequences for the host. A wide range of bacterial communities have been found in association with the oriental fruit fly, Bactrocera dorsalis (Hendel) (Diptera: Tephritidae), an important pest of cultivated fruit in most regions of the world. We evaluated the diversity of gut bacteria in B. dorsalis specimens from several populations in Kenya and investigated the roles of individual bacterial isolates in the development of axenic (germ-free) B. dorsalis fly lines and their responses to the entomopathogenic fungus, Metarhizium anisopliae.ResultsWe sequenced 16S rRNA to evaluate microbiomes and coupled this with bacterial culturing. Bacterial isolates were mono-associated with axenic B. dorsalis embryos. The shortest embryonic development period was recorded in flies with an intact gut microbiome while the longest period was recorded in axenic fly lines. Similarly, larval development was shortest in flies with an intact gut microbiome, in addition to flies inoculated with Providencia alcalifaciens. Adult B. dorsalis flies emerging from embryos that had been mono-associated with a strain of Lactococcus lactis had decreased survival when challenged with a standard dosage of M. anisopliae ICIPE69 conidia. However, there were no differences in survival between the germ-free lines and flies with an intact microbiome.ConclusionsThese findings will contribute to the selection of probiotics used in artificial diets for B. dorsalis rearing and the development of improved integrated pest management strategies based on entomopathogenic fungi.

The Effects of Different Concentrations of Retinoic Acid on the Histological Structure of Liver of Adult Albino Female Mice and Their Prenatal Fetuses

Retinoic acid (RA) an active metabolite of vitamin A, plays essential signaling roles in mammalian embryonic development and adult homeostasis through concentration-dependent activity but in excess, RA is teratogenic. The present study was designed to evaluate the harmful effect of RA on the: liver tissues of the adult pregnant female albino mice and their prenatal fetuses and adult morphological and behavior changes. Forty-five pregnant adult female albino mice were divided into three groups (n=15 for each group). Group I, the control group orally received 0.1ml of olive oil. Group II and III received 25 and 50mg RA/kg B.W. respectively. RA was dissolved in 0.1ml of olive oil and orally given on 7 th , 8 th , and 9 th days of pregnancy. On the 18 th day of gestation, these females were sacrificed and the liver from mother and their prenatal were removed, weighed, and prepared for histological study. The RA treated adult group exhibited behavior changes including general fatigue and loss of appetite, in addition to the morphological changes which included weight loss, change in normal red eye color towards black, and redness in the mouth and chin area associated with loss of hair (fur) around this area. These observations were showed to be more severe in the 50 mg RA group. The results showed that treatment with 25 and 50mg RA caused no significant decrease in the adult liver weight, while in their prenatal fetuses 50mg RA caused a higher significant decrease in the liver weight, but 25 mg RA caused no significant effects on this weight. Treated with 50mg/kg RA caused a highly significant increase in the number of aborted and dead fetuses as compared with other groups. The results of the histological study showed that treatment with both concentrations of RA caused several degrees of the liver damage with disrupted the normal architecture pattern along with hepatocellular steatosis, hypertrophy, and inflammation. In conclusions, RA caused variable degrees of degeneration and destruction of the liver tissues of adult female (mother) and their prenatal. The most important effects of RA are causing hepatocellular steatosis, hypertrophy, and inflammation, and when RA giving during the critical periods of embryonic development, caused harmful effects on the developing liver, therefore treatment with RA should be avoided at any stage of gestation. Keywords: Liver, retinoic acid, embryonic development, vitamin A, histological study. DOI: 10.7176/JBAH/10-18-04 Publication date: September 30 th 2020

The reproductive potential of Pseudobatos productus: Intraspecific and interspecific variation

The reproductive potential of the shovelnose guitarfish, Pseudobatos productus, was described for Bahía Sebastián Vizcaíno, a bay in the western coast of the Baja California peninsula, Mexico, and contrasted with other commercially important fishing sites for this species. The reproductive cycle of P. productus at this bay is annual. Ovulation and fertilization occur during summer and are followed by an eight-month period of embryonic diapause that takes place from September until April of the following year. Subsequently, a four-month period of embryonic development takes place from May to August, after which birth occurs. The approximate length at birth in this study was 20 cm, while the length at sexual maturity for males and females was 90 and 92 cm, respectively. Pseudobatos productus embryos presented a 1:1 sex ratio at birth and the observed mean fecundity (11 pups) is the highest that has been reported for this species. The fecundity of Pseudobatos productus is higher on Bahía Sebastián Vizcaíno than in the Gulf of California and greater than that of other Pseudobatos species. In Mexico, the development of specific management strategies that consider the differences in reproductive parameters between geographical regions are necessary to ensure that P. productus fisheries are sustainable.

Non-Invasive PPG-Based System for Continuous Heart Rate Monitoring of Incubated Avian Embryo.

The chicken embryo is a widely used experimental animal model in many studies, including in the field of developmental biology, of the physiological responses and adaptation to altered environments, and for cancer and neurobiology research. The embryonic heart rate is an important physiological variable used as an index reflecting the embryo’s natural activity and is considered one of the most difficult parameters to measure. An acceptable measurement technique of embryonic heart rate should provide a reliable cardiac signal quality while maintaining adequate gas exchange through the eggshell during the incubation and embryonic developmental period. In this paper, we present a detailed design and methodology for a non-invasive photoplethysmography (PPG)-based prototype (Egg-PPG) for real-time and continuous monitoring of embryonic heart rate during incubation. An automatic embryonic cardiac wave detection algorithm, based on normalised spectral entropy, is described. The developed algorithm successfully estimated the embryonic heart rate with 98.7% accuracy. We believe that the system presented in this paper is a promising solution for non-invasive, real-time monitoring of the embryonic cardiac signal. The proposed system can be used in both experimental studies (e.g., developmental embryology and cardiovascular research) and in industrial incubation applications.

Analysis of the rates of development and growth of Brachymystax lenok Savinovi during artificial reproduction by the industrial method

The article presents the results of the first research on artificial reproduction in industrial conditions of the endemic, narrow-areal subspecies of Brachymystax lenok Savinovi, which lives in lake Markakol, East Kazakhstan region. The indicators of the heat sum characteristic for each stage of development, the rate of development and growth of the Markakolsky lenok from the moment of pre-breeding to late juveniles are described. To develop technological approaches for artificial fish reproduction, one of the most important points is to determine the optimal conditions for each stage and assess the risks (loss of fish products). At the stage of insemination and transportation of eggs to the place of incubation, the loss was 50 %. The largest losses of fish products were registered during the incubation stage. The most painlessly passed the period of holding and lifting on the float, where the loss was only 3 %. When growing pre-larvae and larvae in the pool, the daily waste did not exceed 1 %. Small-sized animals that were unable to adapt to artificial feeds fell into the waste. Losses during this period amounted to 15 % of the previous stage. In General, the yield of juveniles from the moment of fertilization to the end of the experiment was 16 %. The crucial factor in the development and growth of Lenok Markakolosky is the temperature regime. For the period of embryonic development, the most favorable water temperature is 7–8 °C. From the moment of hatching, the water temperature must be increased to 10–12 °C, and the optimal temperature for the cage growing of fingerlings varies from 12 to 14 °C.