Developing Chick Embryo Research Articles

Three-dimensional evaluation of microvascular networks using contrast-enhanced ultrasound and microbubble tracking.

Evaluating tumor microvascular networks with use of contrast-enhanced ultrasound (CEUS) imaging and one-dimensional (1D) linear array transducers have inherit limitations as tumors exist in volume space. The use of a mechanical sweep allows users to overcome this limitation. To that end, we have developed a new method by which a 1D linear array transducer can be mechanically scanned over a region-of-interest to capture a volume of data allowing for the evaluation of microvasculature structures in 3D space. After intravascular injection of a microbubble (MB) contrast agent into a developing chicken embryo, a sequence of CEUS images were acquired using a Vevo 3100 scanner (VisualSonics Inc) and taken at multiple tissue cross-sections. The CEUS images were processed with a singular value filter (SVF) to help remove any clutter signal. MB localization was performed, and frame-to-frame MB movement was analyzed to produce spatial maps depicting blood flow and velocity at each tissue cross-section. Reconstruction of all images allowed visualization of microvascular networks and blood velocity distribution in volume space.

Three-dimensional super-resolution ultrasound imaging of chicken embryos - A validation framework for analysis of microvascular morphology.

The purpose of this present study was to improve the quantification of microvascular networks depicted in three-dimensional (3D) super-resolution ultrasound (SR-US) images and compare results with matched brightfield microscopy and B-mode ultrasound (US) images. Standard contrast-enhanced US (CEUS) images were collected using a high-frequency US scanner (Vevo 3100, FUJIFILM VisualSonics Inc) equipped with an MX250 linear array transducer. Using a developing chicken embryo as our model system, US imaging was performed after administration of a custom microbubble (MB) contrast agent. Guided by stereo microscopy, MBs were introduced into a perfused blood vessel by microinjection with a glass capillary needle. Volume data was collected by mechanically scanning the US transducer throughout a tissue volume-of-interest (VOI) in 90 μm step increments. CEUS images were collected at each increment and stored as in-phase/quadrature (IQ) data (N = 2000 at 152 frames per sec). SR-US images were created for each cross-sectional plane using established data processing methods, and all were then used to form a final 3D volume for subsequent quantification of morphological features. Vessel diameter quantifications from 3D SR-US data exhibited an average error of 1.9% when compared with microscopy images, whereas measures from B-mode US images had an average error of 75.3%. Overall, 3D SR-US images clearly depicted the microvascular network of the developing chicken embryo and measurements of microvascular morphology achieved better accuracy compared to traditional B-mode US.

Effect of in ovo application of hydroxyapatite nanoparticles on chicken embryo development, oxidative status and bone characteristics

ABSTRACT Intensive selection in modern lines of fast-growing chickens has caused several skeletal disorders. Therefore, current research is focused on methods to improve the bones of birds. A new potential solution is in ovo technology using nanoparticles with a high specificity for the bone tissue. Thus, the objective of the present study was to evaluate the effect of in ovo application of hydroxyapatite nanoparticles (HA-NP) in different concentrations (50, 100 and 500 μg/ml colloids) on chicken embryo development, with a particular focus on the oxidative status and bone characteristics of the embryo. The results showed that in ovo treatment with HA-NP did not negatively affect hatchability and body weight. However, bone weight was reduced in 500 μg/ml group. The concentrations of calcium, phosphorus and crude ash were not affected. The modulatory effect of HA-NP was observed on the basis of antioxidative markers – superoxide dismutase, total antioxidant status, malondialdehyde in serum and selected tissues. Glutathione concentration in serum suggested higher metabolic stress. Among bone turnover markers, the concentration of osteocalcin was found to be significantly affected by HA-NP injection. Thus, the in ovo application of HA-NP could modify the molecular responses at the stage of embryogenesis but these changes were not reflected in embryo growth and even slowed down bone development. Nevertheless, the question for the follow-up research is whether in ovo administration of HA-NP would affect the antioxidative status and bone turnover resulting in improved bone conditions and body gain in post hatch chickens.

In the Spotlight-Established Researcher.

Tamara Franz-Odendaal holds the NSERC Chair Women in Science and Engineering (Atlantic Canada) and is a Fellow of the American Association of Anatomists Tamara is a Guest Co-Editor of this special issue on Cavefish Website: www.bonedevelopmentlab.ca With whom and where did you study? I completed my undergraduate, MSc and PhD degrees at the University of Cape Town, South Africa. For my MSc degree, I studied gene expression during eye development in chicken embryos under the supervision of Dr. Susan Kidson. My PhD thesis explored paleopathologies and paleodiets of 5 million-year-old fossil herbivores from a South African locality called Langebaanweg. My PhD supervisors were paleontologist Dr. Anusuya Chinsamy-Turan and archaeologist Dr. Julia Lee-Thorpe. Notably, these three supervisors are top female scientists, two of whom had families when I was in their research groups. I completed a short-term DAAD scholarship to pursue a post-doc with Dr. Thomas Kaiser at the University of Greifswald (Germany) and then conducted a 3.5-year post-doc with Dr. Brian Hall (Dalhousie University, Canada), where I got my first true taste of the EvoDevo field. What got you interested in Biology? When did you know EvoDevo was for you? I have been interested in animals and the natural world from a young age. My MSc degree was in developmental biology and I branched out into paleontology for my PhD. Therefore, merging my fascination with embryos and fossils was a natural fit for my post-doc. To have the opportunity to do this with such a remarkable scientist as Dr. Hall was a wonderful experience. If you are amazed at animal diversity then EvoDevo may be for you too since how can you not wonder how that diversity arose both over evolutionary and over developmental time scales. What has been your biggest challenge in getting to your position? My biggest challenge to getting to my position was job searching while having a toddler, being a permanent resident of Canada, and having a degree from a university that was not well known in Canada. I received my first faculty position as an NSERC (Natural Sciences and Engineering Research Council, Canada) University Faculty Award recipient. This program provided me the mechanism for establishing my research program at Mount Saint Vincent University by giving me a reduced teaching load in my first three-years. As an active and productive researcher in Canada, I often have to justify why I chose a primarily undergraduate institution as my home. There are many benefits to teaching at a smaller university such as closer interactions with students and a sense of community. The first time I was exposed to research was during my undergraduate degree and it was an immensely rewarding experience. I view training undergraduates in research methods and analysis as incredibly important since these are the students that become our graduate students and future scientists. Or alternatively, they become our doctors, dentists, and veterinarians; professions that require an understanding of the scientific process. What advice do you have for junior EvoDevo researchers? My advice for graduate students and post-docs interested in EvoDevo is to thoroughly learn as many different techniques as possible, work on different organisms (this will become important if you need to teach EvoDevo or Developmental Biology), and pick your advisors based on how they treat their trainees and their productivity. It is okay (and the norm) to randomly email PI's to ask if they are taking on new students rather than waiting for a graduate position announcement. Do your homework though, and make sure you have read about their research and that you really want to work with them. We established PI's receive numerous applications from students for positions and are very adept at picking out the students who have done some homework about our research. Your first email to us should be to introduce yourself and tell us why your interests or past experiences align with our research group's interests. Always attach your CV or resumé.

Dynamic distribution of gut microbiota during embryonic development in chicken

The gut microbiota is a complex ecological community and widely recognized in many aspects of research, but little is known on the relation between gut microbiota and embryonic development in chickens. The aim of this study was to explore the dynamic distribution of gut microbiota in chickens' embryos during stages of developments (chicken embryos that had incubated until day 3 [E3], day 12 [E12], and day 19 [E19]). Here, 16S rRNA gene sequencing was performed on the gut microbiota in chicken embryos across different developmental stages. Twenty-one phyla and 601 genera were present in chicken embryos, and 96 genera such as Ochrobactrum, Phyllobacterium, and Amycolatopsis were the core microbiota in the 3 stages of development. Second, 94 genera of microbes were found to change significantly between E3 and E12, and 143 genera significantly differed between E12 and E19 in chicken embryos (P < 0.05). Ochrobactrum and Amycolatopsis decreased with growth changes: E3 (30.4%), E12 (25.1%), and E19 (13.6%) and E3 (11.5%), E12 (7.4%), and E19 (5.6%), respectively. Contrarily, Phyllobacterium increased to 47.9% at E19, indicating the growing trend of microbial diversity among the embryos' development. Moreover, the principal component analysis showed a high level of similarities between E3 and E12 compared with E19, whereas the alpha analysis showed more diversity of gut microbiota at E19. Furthermore, the functional predictions showed that metabolic pathways such as energy metabolism and genetic information processing were significantly enriched on day 3 and day 12 in our study, suggesting their strong influence on growth, development, and immunity of chicken embryos. Our findings provide insights into the understanding of dynamic shifts of gut microbiota during chicken embryonic growth.

ВЛИЯНИЕ ФАКТОРОВ ВНЕШНЕЙ СРЕДЫ НА РАЗВИТИЕ ЭМБРИОНА, ЕГО ИММУННЫЙ СТАТУС И РЕЗУЛЬТАТЫ ИНКУБАЦИИ

The article is devoted to the study of the problem of external factors influence on the development of the embryo and the immune status of chickens. This is primarily due to the fact that the sensitivity of embryos to the impact of various damaging agents of the external environment, primarily abiotic factors, such as oxygen deficiency, sharp temperature fluctuations beyond the optimum, mechanical damage and other influences, affect the course of morphogenetic processes, disrupting the rate of development of individual organs, causing the appearance of malformations of embryos and, in many cases, leading to death. The object of the study is chicken embryos and chickens up to ten days old. The aim of the work was to develop the most optimal incubation technology that would help stimulate the development of chicken embryos and did not require additional equipment and training costs. The work consists of an introduction, article materials, conclusions and a list of references. The introduction includes the relevance of the research, its goals and objectives, object, subject of research and research methods. The first section describes research on the correct selection, storage of eggs and the correct use of the incubator. The second section contains data on the study of the influence of various factors on the immune system of chicken embryos and chickens. In general, the analysis of factors given in the literature allows us to conclude about the influence of these factors on the development of chickens, increasing their safety and productivity. The material of the article shows that, while studying these factors, they primarily affect the immune system.

Genomic Sequence of the New Attenuated Vaccine Strain Neethling-RIBSP of the Lumpy Skin Disease Virus.

We report here the draft genome sequence of the new attenuated strain Neethling-RIBSP of the lumpy skin disease virus, obtained by sequential and alternating passages in cell culture and developing chicken embryos. Genome sequencing allowed the identification of differentiation markers of the new strain.

Methionine improves feather follicle development in chick embryos by activating Wnt/β-catenin signaling

This study was conducted to explore the regulatory role of methionine (Met) in feather follicle and feather development during the embryonic period of chicks. A total of 280 fertile eggs (40 eggs/group) were injected with 0, 5, 10, 20 mg of L-Met or DL-Met/per egg on embryonic day 9 (E9), and whole-body feather and skin tissues were collected on E15 and the day of hatching (DOH). The whole-body feather weight was determined to describe the feather growth, and the skin samples were subjected to hematoxylin and eosin staining and Western blotting for the evaluation of feather follicle development and the expressions of Wingless/Int (Wnt)/β-catenin signaling pathway proteins, respectively. The results showed that L- or DL-Met did not affect the embryo weight (P > 0.05), but increased the absolute and relative whole-body feather weights. Specifically, 5 and 10 mg of L-Met and 5, 10, and 20 mg of DL-Met significantly increased the absolute feather weight at E15 (P < 0.05), and 10 mg of L-Met and 5 and 10 mg of DL-Met significantly increased the absolute and relative feather weight on the DOH (P < 0.05). Moreover, a main effect analysis suggested that changes in the embryo and feather weights were related to the Met levels (P < 0.05) but not the Met source (P > 0.05). The levels of L- and DL-Met were quadratically correlated with the absolute and relative feather weights of chicks on the DOH (P < 0.05). Correspondingly, all doses of L- and DL-Met significantly increased the diameter and density of feather follicles on the DOH (P < 0.05), as well as the activity of Wnt/β-catenin on E15 and the DOH (P < 0.05). In conclusion, injection of either L- or DL-Met can improve feather follicle development by activating Wnt/β-catenin signaling, and thereby promoting feather growth; furthermore, no difference in feather growth was found between L- and DL-Met treatments. Our findings might provide a nutritional intervention for regulating feather growth in poultry production.

Effect of abamectin on development of chick embryo

Effect of abamectin on development of chick embryo

Effect of zinc nanoparticles on embryo and chicken growth, and the content of zinc in tissues and faeces

The hypothesis was that owing to their high bioavailability, zinc oxide nanoparticles (NanoZnO) can effectively replace (Zn) salts and reduce Zn excretion with faeces. The objective of this study was to investigate the effects of NanoZnO on the development of chicken embryos, the growth of broiler chickens, and Zn excretion with faeces. At day 1 of incubation, 120 eggs were randomly divided between a control group (not injected) and groups injected with a hydrocolloid of NanoZnO in increasing concentrations (50, 100, 500 mg/L). At day 19 of incubation, no differences were observed in the bodyweight, but 100 and 500 mg/L affected liver and heart weights, indicating that high levels of NanoZnO may induce differential organ development. In the subsequent experiment, 308 chickens were randomly divided into six groups. The control diet was supplemented with 55 mg Zn/kg (standard level), the 0 group received no Zn supplement, and groups fed NanoZnO received 25%, 50%, 75%, and 100% of the standard level. The 100% replacement of ZnO with NanoZnO increased the chickens’ bodyweight compared with the standard level of ZnO, but to the same level as the diet without ZnO supplementation. Furthermore, NanoZnO did not reduce the content of Zn in faeces, which was only significantly lower in the group without ZnO supplementation in comparison with other groups. The results indicate that the replacement of ZnO with NanoZnO had no negative effects on chicken growth. Compared with ZnO, NanoZnO did not reduce Zn excretion with faeces.&#x0D; Keywords: broiler, development, excretion, mineral, nanonutrition

Growth and cardiovascular development are repressed by florfenicol exposure in early chicken embryos

Florfenicol (FLO) is one of the most popular antibacterial drugs used in veterinary clinics and aquaculture. The drug was found to decrease the hatchability of eggs laid by treated hens in veterinary clinics and research work. However, the pathological changes in developing embryos and their cardiovascular system and the mechanism underlying FLO-induced embryonic death remain unclear. In the present study, fertilized eggs laid by hens treated with a therapeutic dose of FLO were collected and incubated. Results showed that FLO exposure repressed embryonic development and induced early embryonic death. As a result, FLO decreased the hatchability and increased the proportion of weak chicks. Moreover, FLO exposure led to embryonic lethality and inhibited the development of chick embryos as characterized by decreased weights, lagging distribution of Hamburger–Hamilton stages, and dysplastic eyes. Pathological examination indicated that FLO exposure affected the normal development of the heart in 4.5-day-old chick embryos, as characterized by shorter transverse cardiac diameter, disordered arrangement of trabecular muscles in ventricles, and reduced thickness of ventricular walls. Furthermore, FLO decreased blood vascular densities and downregulated the expression levels of key angiogenesis-related genes, including the vascular endothelial growth factor and fibroblast growth factor, in the yolk sac membrane. These findings indicated that FLO exposure restricted vascular development during early embryonic development. In summary, our data suggest that the restricted growth and abnormal cardiovascular development may be responsible for FLO-induced early embryonic death. Thus, these findings can be useful for guiding the proper use of FLO and in laying a foundation for further studies on the mechanism of FLO-induced embryonic toxicity.

Smokeless tobacco ‘sadagura’ and areca nut extract exposure induces extensive embryotoxicity in chick embryo, Gallus gallus domesticus

Areca nut (AN) and sadagura (SG, homemade smokeless tobacco) are often consumed alone or in combination irrespective of gender including pregnant women in the southern region of Assam, India. However, very few studies have been carried out so far to evaluate its ill effect during embryogenesis. The present study aims to determine the effects of AN, SG, and combination of both (AN + SG) in developing chick embryos as it serves as an excellent model for teratogenic and developmental toxicity study owing to its similarity with the human embryo. Fertile White Leghorn chicken eggs (Gallus gallus domestucus) were exposed to different concentrations of 0.125, 0.25, 0.5, and 1 mg/egg of AN, SG, and AN + SG extract, respectively. The eggs were divided into four groups: control, AN extract-, SG extract-, and AN + SG-treated group. Three different parameters, viz. mortality rate, morphometric measurements, and qualitative anomalies, were studied to observe teratogenic effects. Results indicated a dose-dependent increase in mortality rate in all the treatment groups. Also, quantitative measures suggested significant decrease (p < 0.001) in wet body weight, crown–rump length, anterior–posterior head length, and eyeball diameter in all the concentration of AN, SG and AN + SG of treatment groups when compared to control group. Compared to control, anomalies like microcephaly, microphthalmia, deformed beak, hemorrhage, omphalocele, flexed limbs, and ectopia cordis were prominent in treated groups. Our findings depict organ-specific as well as systemic defects in the developing embryos. Our results suggest that exposure to AN, SG, and AN + SG causes adverse developmental abnormalities and embryo mortality in the chick embryo.

Testosterone Promotes the Proliferation of Chicken Embryonic Myoblasts Via Androgen Receptor Mediated PI3K/Akt Signaling Pathway.

Testosterone (T) is essential for muscle fiber formation and growth. However, the specific mechanism by which T regulates skeletal muscle development in chicken embryos remains unclear. In this study, the role of T in myoblast proliferation both in vivo and in vitro was investigated. Results showed that the T administration significantly increased the ratio of breast muscle and leg muscle. T induced a significant increase in the cross-sectional area (CSA) and density of myofiber and the ratio of PAX7-positive cells in the skeletal muscle. Exogenous T also induced the upregulation of myogenic regulatory factors (MRFs) and cyclin-dependent kinases (CDK2)/Cyclin D1 (CCND1) and protein levels of androgen receptor (AR), p-Akt and PAX7. Furthermore, T treatment significantly promoted myoblasts cultured in vitro entering a new cell cycle and increased PAX7-positive cells. The mRNA and protein expression of AR and PAX7 were upregulated when treated with T compared to that of the control. The addition of T induced proliferation accompanied by increasing AR level as well as PI3K (Phosphoinositide 3-kinase)/Akt activation. However, T-induced proliferation was attenuated by AR, PI3K, and Akt-specific inhibitors. These data indicated that the pro-proliferative effect of T was regulated though AR in response to the activation of PI3K/Akt signalling pathway.

Preliminary evaluation of application of a 3-dimensional network structure of siloxanes Dergall preparation on chick embryo development and microbiological status of eggshells

The spatial network structure of Dergall is based on substances nontoxic to humans and the environment which, when applied on solid surfaces, creates a coating that reduces bacterial cell adhesion. The bacteriostatic properties of siloxanes are based on a purely physical action mechanism which excludes development of drug-resistant microorganisms. The aims of the present study were to 1) evaluate a Dergall layer formed on the eggshell surface regarding the potential harmful effects on the chick embryo; 2) evaluate antimicrobial activity and estimate the prolongation time of Dergall's potential antimicrobial activity. Dergall at a concentration of 0.6% formed a layer on the eggshell surface. In vitro testing of the potential harmful effects of Dergall by means of a hen embryo test of the chorioallantoic membrane showed no irritation reaction at a concentration of 3% and lower. The hatchability of the groups sprayed with a Dergall water solution with a concentration of 0 to 5% was 89.1 to 93.8% for fertilized eggs (P > 0.05) but decreased to 63.7% (P < 0.05) in the group sprayed with a 6% concentration of the solution. This phenomenon was caused by embryo mortality in the first week of incubation. At the concentration of 0.6%, Dergall exhibited strong antibacterial properties against bacteria such as Staphylococcus aureus, Escherichia coli, Shigella dysenteriae, Shigella flexneri, and Salmonella typhimurium. For Streptococcus pyogenes, the highest antibacterial activity of Dergall was reported in the concentrations of 100 and 50%. For Pseudomonas aeruginosa, no antibacterial activity of Dergall was generally observed, but in vivo testing showed a strong decrease of all gram-negative bacteria growth. Moreover, a prolonged antimicrobial effect lasting until 3 D after disinfection was observed, which makes Dergall a safe and efficient disinfectant.

A suggested bisphenol A metabolite (MBP) interfered with reproductive organ development in the chicken embryo while a human-relevant mixture of phthalate monoesters had no such effects

ABSTRACTBisphenol A (BPA) and phthalate diesters are ubiquitous environmental contaminants. While these compounds have been reported as reproductive toxicants, their effects may partially be attributed to metabolites. The aim of this study was to examine reproductive organ development in chicken embryos exposed to the BPA metabolite, 4-methyl-2,4-bis(4-hydroxyphenyl)pent-1-ene (MBP; 100 µg/g egg) or a human-relevant mixture of 4 phthalate monoesters (85 µg/g egg). The mixture was designed within the EU project EDC-MixRisk based upon a negative association with anogenital distance in boys at 21 months of age in a Swedish pregnancy cohort. Chicken embryos were exposed in ovo from an initial stage of gonad differentiation (embryonic day 4) and dissected two days prior to anticipated hatching (embryonic day 19). No discernible effects were noted on reproductive organs in embryos exposed to the mixture. MBP-treated males exhibited retention of Müllerian ducts and feminization of the left testicle, while MBP-administered females displayed a diminished the left ovary. In the left testicle of MBP-treated males, mRNA expression of female-associated genes was upregulated while the testicular marker gene SOX9 was downregulated, corroborating a feminizing effect by MBP. Our results demonstrate that MBP, but not the phthalate monoester mixture, disrupts both male and female reproductive organ development in an avian embryo model.

Stable integration of an optimized inducible promoter system enables spatiotemporal control of gene expression throughout avian development.

ABSTRACTPrecisely altering gene expression is critical for understanding molecular processes of embryogenesis. Although some tools exist for transgene misexpression in developing chick embryos, we have refined and advanced them by simplifying and optimizing constructs for spatiotemporal control. To maintain expression over the entire course of embryonic development we use an enhanced piggyBac transposon system that efficiently integrates sequences into the host genome. We also incorporate a DNA targeting sequence to direct plasmid translocation into the nucleus and a D4Z4 insulator sequence to prevent epigenetic silencing. We designed these constructs to minimize their size and maximize cellular uptake, and to simplify usage by placing all of the integrating sequences on a single plasmid. Following electroporation of stage HH8.5 embryos, our tetracycline-inducible promoter construct produces robust transgene expression in the presence of doxycycline at any point during embryonic development in ovo or in culture. Moreover, expression levels can be modulated by titrating doxycycline concentrations and spatial control can be achieved using beads or gels. Thus, we have generated a novel, sensitive, tunable, and stable inducible-promoter system for high-resolution gene manipulation in vivo.

The ameliorative effect of curcumin extract on the morphological and skeletal abnormalities induced by sunset yellow and tartrazine in the developing chick embryo Gallus domesticus

Previous studies have suggested that food dyes are responsible for causing number of health problems. The study under consideration aims to show the possible morphological and skeletal malformation induced due to in ovo administration of sunset yellow (SY) and tartrazine (Tz) with or without curcumin (Cur) during organogenesis of developing chick embryo at doses 1.575mg/egg, 0.375mg/egg and 3mg/kg eggs for SY, Tz and Cur comparing with control. The investigation revealed evident reduction in the weight and length of embryos as well as malformations in feather, head, and limbs. Most of the congenital malformations were seen in SY and Tz injected groups such as short beak, excencephaly, kniked tail and pygostyle, curved scapula and retardation in the degree of ossification were the most evident in endoskeleton malformation. In addition, the length of ossified long bones in SY and Tz groups was affected. Co-administration of Cur with SY and Tz ameliorate the reversed effect of SY and Tz on the shape, length, body weight and skeleton of embryos.

Effects of Quetiapine on Neural Tube Development in the Early Stage of Chicken Embryos.

To investigate the effects of quetiapine exposure on neural tube development in early stage chicken embryos. Eighty-four fertilised specific pathogen-free chicken eggs were divided into four equal groups (groups 1?4). Three experimental groups (groups 2, 3 and 4) and a single control group (group 1) were used. Each egg in group 2 (n=21) was injected with 20 ?L of saline after 30 hours of incubation. Eggs in groups 3 and 4 were injected with 0.02 ml of a solution containing 400 and 800 ?g of quetiapine dose, respectively. Incubation was continued until the end of 72 hours. All embryos were then removed from the eggs and histopathologically examined. Normal development and the closed neural tubes were shown in 18, 16, 13 and 9 embryos in groups 1 2, 3 and 9, respectively, of the 84 embryos incubated. Open neural tubes were found in one, three and five embryos in groups 2, 3 and 5, respectively. Also, developmental anomalies were found in three, four, five and seven embryos in groups 1, 2, 3 and 4, respectively. Moreover, no significant relationship between NTD and quetiapine exposure had been found. Quetiapine has no significant effect on the occurrence of neural tube defects in the chicken embryo model.

Effect of Pinkwater BioSolve on expression of proinflammatory cytokines and histological changes in Gallus domesticus embryo

Pinkwater Biosolve (BioSolve®) is one bioremediating chemical which has been widely used for cleanup of crude oil spill in Nigeria. It is a water-based formulation of nonionic surfactants and other specialty chemicals. The level of toxicity resulting from environmental exposure to this chemical has not been well understood.The level of expression of proinflammatory cytokines and histological changes in Gallus domesticus embryo were investigated.The embryo were pretreated with different doses of BioSolve, soil water from remediated soil sample, 10% soluble crude oil portion and a combination of the BioSolve with the soluble crude portion all constituted in normal saline solution. Reverse transcriptase PCR technique was used to assess the expression of hepatic proinflammatory cytokines. Histological examination was also carried out on liver fragments. The results showed that the pretreatment caused lesion on hepatocytes of all tested chick embryos except in the group administered with normal saline solution when compared with the normal control. The chick embryo exposed to 0.5 mg/kg BioSolve, 5% decanted soil water (v/v) obtained from crude oil remediated (using BioSolve) soil, and 10% (v/v) decanted crude oil remediated (using BioSolve) soil water all showed significant expression (at p < 0.05) of IFNγ, TGFβ1, IL-1β, IL-2 and TNF. The group treated with 10% soluble portion of crude oil showed significant changes in their expression pattern when compared with the control; TNF was up regulated, while IL-1β, IFNγ and TGFβ1 were down regulated. Only TNF was upregulated at p < 0.05 indicating the chances of soluble portion of crude oil causing cancer. IFNγ, TGFβ1, IL-1β and IL-2 were all down regulated significantly at p < 0.05 due to exposure to a combination of 10% soluble crude and 0.036 mg/kg BioSolve. The combination of 10% soluble crude and 0.36 mg/kg BioSolve caused lethal effect to the developing chick embryo.

Canonical Wnt signaling promotes pacemaker cell specification of cardiac mesodermal cells derived from mouse and human embryonic stem cells.

Cardiac differentiation of embryonic stem cells (ESCs) can give rise to de novo chamber cardiomyocytes and nodal pacemaker cells. Compared with our understanding of direct differentiation toward atrial and ventricular myocytes, the mechanisms for nodal pacemaker cell commitment are not well understood. Taking a cue from the prominence of canonical Wnt signaling during cardiac pacemaker tissue development in chick embryos, we asked if modulations of Wnt signaling influence cardiac progenitors to bifurcate to either chamber cardiomyocytes or pacemaker cells. Omitting an exogenous Wnt inhibitor, which is routinely added to maximize cardiac myocyte yield during differentiation of mouse and human ESCs, led to increased yield of spontaneously beating cardiomyocytes with action potential properties similar to those of native sinoatrial node pacemaker cells. The pacemaker phenotype was accompanied by enhanced expression of genes and gene products that mark nodal pacemaker cells such as Hcn4, Tbx18, Tbx3, and Shox2. Addition of exogenous Wnt3a ligand, which activates canonical Wnt/β-catenin signaling, increased the yield of pacemaker-like myocytes while reducing cTNT-positive pan-cardiac differentiation. Conversely, addition of inhibitors of Wnt/β-catenin signaling led to increased chamber myocyte lineage development at the expense of pacemaker cell specification. The positive impact of canonical Wnt signaling on nodal pacemaker cell differentiation was evidenced in direct differentiation of two human ESC lines and human induced pluripotent stem cells. Our data identify the Wnt/β-catenin pathway as a critical determinant of cardiac myocyte subtype commitment during ESC differentiation: endogenous Wnt signaling favors the pacemaker lineage, whereas its suppression promotes the chamber cardiomyocyte lineage.