The Making of a Flight Feather: Bio-architectural Principles and Adaptation.

The evolution of flight in feathered dinosaurs and early birds over millions of years required flight feathers whose architecture features hierarchical branches. While barb-based feather forms were investigated, feather shafts and vanes are understudied. Here, we take a multi-disciplinary approach to study their molecular control and bio-architectural organizations. In rachidial ridges, epidermal progenitors generate cortex and medullary keratinocytes, guided by Bmp and transforming growth factor ß (TGF-ß) signaling that convert rachides into adaptable bilayer composite beams. In barb ridges, epidermal progenitors generate cylindrical, plate-, or hooklet-shaped barbule cells that form fluffy branches or pennaceous vanes, mediated by asymmetric cell junction and keratin expression. Transcriptome analyses and functional studies show anterior-posterior Wnt2b signaling within the dermal papilla controls barbule cell fates with spatiotemporal collinearity. Quantitative bio-physical analyses of feathers from birds with different flight characteristics and feathers in Burmese amber reveal how multi-dimensional functionality can be achieved and may inspire future composite material designs. VIDEO ABSTRACT.

Gamma-oryzanol supplemented in extender enhances the quality of semen cryopreservation and alters proteomic profile in Thai swamp buffalo.

Reactive oxygen species (ROS) exert an adverse effect on sperm quality during the freezing process. Gamma-oryzanol is an effective antioxidant and has the ability to inhibit lipoperoxidation in various cells. Therefore, this study aims to investigate the effect of gamma-oryzanol supplementation in extender on post-thawed motility and proteomic profiles of swamp buffalo spermatozoa. Each ejaculate of an individual bull was divided into four equal aliquots. Gamma-oryzanol was supplemented at 0 (control), 0.1, 0.25, and 0.5 mM in tris-citrate egg yolk extender. The parameters of sperm motility were evaluated using computer assisted semen analyzer (CASA). The results showed that the progressive motility was significantly higher in 0.5 mM of gamma-oryzanol supplementation group when compared with the control group (p < 0.05), but no significant differences were observed among the treatments. In addition, a proteomic approach was applied to analyze the differentially expressed proteins in post-thawed sperm with or without gamma-oryzanol supplementation in extender. We confirmed that 2-phospho-d-glycerate hydro-lyase (ENO1), glutathione s-transferase mu 1 (GSTM1), phospholipid hydroperoxide glutathione peroxidase (GPX4), outer dense fiber protein 2 (ODF2), tektin-4 (TEKT4), tubulin beta-4B chain (TUBB4B), and ATP synthase subunit beta (ATP5B) were up-regulated in 0.5 mM of gamma-oryzanol supplementation group, which might be associated with the improved post-thawed motility observed in this treatment group. These results demonstrate the beneficial effect of gamma-oryzanol on post-thawed survival of swamp buffalo spermatozoa and help advance the understanding about molecular metabolism of sperm in this species.

Derivation and characterization of putative embryonic stem cells isolated from blastoderms of Taiwan Country chicken for the production of chimeric chickens.

The conservation of Taiwan Country chicken (TCC) is important due to concerns for the local breed's adaptability to the area and disease resistance. Furthermore, the genetic resource base of native chickens can be used to improve egg and meat production efficiency in commercial TCC. As the embryonic stem cells (ESCs) hold great potential for regenerative medicine and species conservation, the aims of this study were to isolate and characterize ESCs of TCC. The blastodermal cells (BCs) were isolated from the zona pellucida of stage X chicken embryos and cultured in conditioned medium for the proliferation and maintenance of BCs in vitro. The quantitative real-time polymerase chain reaction (qPCR) results showed that POUV, SOX2 and NANOG were expressed in the putative ESCs. In addition, the expression of pluripotent markers, SSEA-1 and SSEA-4, was detected. The DiI-stained ESCs were injected into the dorsal aorta of the E3.5 recipient fetuses soon after staining and the injected embryos were continuously incubated and checked on day 7 of incubation. It was shown that some DiI-positive cells were found in the 7-d-old chimeric embryos. The results demonstrated that some pluripotent cells existed in the cultured BCs for the production of germline chimeric embryos from TCC.

Increased luteal tissues after secondary corpus luteum formation leads to enhanced progesterone concentrations and improved fertility in repeat-breeder dairy cows during heat stress condition in tropical climate.

Relatively, little is known about the corpus luteum (CL) function in early pregnancy after the successful treatment of luteal phase deficiency in repeat-breeder dairy cows when exposed to extreme environments under tropical climate. To investigate the influence of increased tissues of corpora lutea (CLs) by inducing secondary CL based on progesterone (P4) concentration and fertility in repeat-breeder dairy cows undergoing the fixed-time artificial insemination (FTAI) protocol, 32 cows were treated with gonadotropin releasing hormone (GnRH) on day 5 post-induction (experiment 1). In experiment 2, 213 cows were bred using the short-term FTAI protocol. On day 5 post-FTAI, cows were divided into two groups: treatment with (GnRH5-treated group) or without (GnRH5-untreated group) GnRH. The temperature-humidity index ranged from 77.3 to 82.8. Cows bearing two CLs had greater P4 concentrations than cows bearing only one CL on their ovaries (P < 0.05). Pregnancy rates were greater in GnRH5-treated group than the GnRH5-untreated group (P < 0.01). Moreover, repeat-breeder cows bearing two CLs had a greater likelihood of pregnancy (odds ratio = 20.86) than cows bearing only one CL on their ovaries (P < 0.01). Under heat stress condition, the results highlighted that increasing luteal tissues by creating secondary CL leads to enhanced peripheral P4 concentrations and improved pregnancy outcomes in repeat-breeder dairy cows.

Melatonin supplementation improved cryopreserved Thai swamp buffalo semen.

The production of reactive oxygen species (ROS) during cryopreservation process impairs the sperm characteristics and fertilizing ability. However, melatonin, an antioxidant, could protect spermatozoa against this cell damage during cryopreservation. Therefore, we attempted to evaluate whether the melatonin supplementing in the semen extender could improve the sperm quality of swamp buffalo during cryopreservation. The semen collected from six swamp buffalo bulls were diluted with tris-citrate egg yolk extender supplementing with 0, 0.1, 0.5, 1.0, 2.0 and 3.0 mM of melatonin. The parameters of sperm viability and motility were evaluated using computer-assisted semen analyser (CASA) after cryopreservation on days 1, 7, 15 and 30. The group supplemented with 1.0 mM melatonin exhibited the higher viability after cryopreservation on days 1, 7, 15 and 30 with 58.346 ± 2.1a , 57.586 ± 2.0a , 55.082 ± 1.8a and 55.714 ± 1.8a , respectively, and showed the best results of motility parameters. However, higher concentration of melatonin at 3.0 mM impaired all the parameters. In conclusion, the addition of melatonin at 1 mM to semen extender could exert the best protection against sperm damage in swamp buffalo bull during cryopreservation.

Morpho-regulation in diverse chicken feather formation: Integrating branching modules and sex hormone-dependent morpho-regulatory modules.

Many animals can change the size, shape, texture and color of their regenerated coats in response to different ages, sexes, or seasonal environmental changes. Here, we propose that the feather core branching morphogenesis module can be regulated by sex hormones or other environmental factors to change feather forms, textures or colors, thus generating a large spectrum of complexity for adaptation. We use sexual dimorphisms of the chicken to explore the role of hormones. A long-standing question is whether the sex-dependent feather morphologies are autonomously controlled by the male or female cell types, or extrinsically controlled and reversible. We have recently identified core feather branching molecular modules which control the anterior-posterior (bone morphogenetic orotein [BMP], Wnt gradient), medio-lateral (Retinoic signaling, Gremlin), and proximo-distal (Sprouty, BMP) patterning of feathers. We hypothesize that morpho-regulation, through quantitative modulation of existing parameters, can act on core branching modules to topologically tune the dimension of each parameter during morphogenesis and regeneration. Here, we explore the involvement of hormones in generating sexual dimorphisms using exogenously delivered hormones. Our strategy is to mimic male androgen levels by applying exogenous dihydrotestosterone and aromatase inhibitors to adult females and to mimic female estradiol levels by injecting exogenous estradiol to adult males. We also examine differentially expressed genes in the feathers of wildtype male and female chickens to identify potential downstream modifiers of feather morphogenesis. The data show male and female feather morphology and their color patterns can be modified extrinsically through molting and resetting the stem cell niche during regeneration.

Acute Heat Stress Changes Protein Expression in the Testes of a Broiler-Type Strain of Taiwan Country Chickens.

Heat stress leads to decreased fertility in roosters. This study investigated the global protein expression in response to acute heat stress in the testes of a broiler-type strain of Taiwan country chickens (TCCs). Twelve 45-week-old roosters were randomly allocated to the control group maintained at 25°C, and three groups subjected to acute heat stress at 38°C for 4 h, with 0, 2, and 6 h of recovery, respectively. Testis samples were collected for hematoxylin and eosin staining, apoptosis assay, and protein analysis. The results revealed 101 protein spots that differed significantly from the control following exposure to acute heat stress. The proteins that were differentially expressed participated mainly in protein metabolism and other metabolic processes, responses to stimuli, apoptosis, cellular organization, and spermatogenesis. Proteins that negatively regulate apoptosis were downregulated and proteins involved in autophagy and major heat shock proteins (HSP90α, HSPA5, and HSPA8) were upregulated in the testes of heat-stressed chickens. In conclusion, acute heat stress causes a change in protein expression in the testes of broiler-type B strain TCCs and may thus impair cell morphology, spermatogenesis, and apoptosis. The expression of heat shock proteins increased to attenuate the testicular injury induced by acute heat stress.

The effect of Xenopus laevis egg extracts with/without BRG1 on the development of preimplantation cloned mouse embryos.

SummaryMuch effort has been devoted to improving the efficiency of animal cloning. The aim of this study was to investigate the effect of BRG1 contained in Xenopus egg extracts on the development of cloned mouse embryos. The results showed that mouse NIH/3T3 cells were able to express pluripotent genes after treatment with egg extracts, indicating that the egg extracts contained reprogramming factors. After co-injection of Xenopus egg extracts and single mouse cumulus cells into enucleated mouse oocytes, statistically higher pronucleus formation and development rates were observed in the egg Extract- co-injected group compared with those in the no egg extract-injected (NT) group (38-66% vs 18-34%, P<0.001). Removal of BRG1 protein from Xenopus egg extracts was conducted, and the BRG1-depleted extracts were co-injected with single donor cells into recipient oocytes. The results showed that the percentages of pronucleus formation were significantly higher in both BRG1-depleted and BRG1-intact groups than that in the nuclear transfer (NT) group (94, 64% vs 50%, P<0.05). Furthermore, percentages in the BRG1-depleted group were even higher than in the BRG1-intact group (94% vs 64%). More confined expression of Oct4 in the inner cell mass (ICM) was observed in the blastocyst derived from the egg extract-injected groups. However, Nanog expression was more contracted in the ICM of cloned blastocysts in the BRG1-depleted group than in the BGR1-intact group. Based on the present study, BRG1 might not play an essential role in reprogramming, but the factors enhancing pronucleus formation and development of cloned mouse embryos are contained in Xenopus egg extracts.

Annotation of differential protein expression in the hypothalami of layer-type Taiwan country chickens in response to acute heat stress.

The hypothalamus is the coordinating center for maintaining temperature homeostasis. In this study, global protein expression in the hypothalami of layer-type Taiwan country chickens in response to acute heat stress was investigated. Twelve 30-week-old female TCCs were divided into three acute heat-stressed groups, namely acute heat stress at 36 °C for 4 h with 0 h (without recovery, H4R0), 2 h (H4R2), or 6 h (H4R6) of recovery. A control group was maintained at 25 °C. Hypothalamus samples were collected at the end of each time point for proteomic analysis. The analysis results revealed that 134 protein spots representing 118 distinct proteins exhibited differential expressions after acute heat stress treatment. Results of gene ontology analysis showed that most of the differentially expressed proteins are involved in carbohydrate metabolism, cellular processes, actin cytoskeleton organization, and responses to stimuli. Functional pathway analysis results suggested that the proteins are associated with networks of carbon metabolism, glycolysis, and gluconeogenesis. Upregulation of the expression of triosephosphate isomerase, phosphoglycerate kinase, pyruvate kinase, alpha-enolase, glycogen phosphorylase (brain form), phosphoglucomutase, L-lactate dehydrogenase A chain and downregulation of 6-phosphogluconolactonase expression indicated an increase in the glycolytic activity and glucose supply for ATP production in the hypothalami in response to heat stress. By contrast, upregulated expressions of heat shock protein 90 alpha, glutathione S-transferase 2s, peroxiredoxin-1, and dihydropyrimidinase-like 2 suggested that acute heat stress adversely affects the hypothalamus; thus, it induces mechanisms that prevent oxidative damage and endoplasmic reticulum stress. In conclusion, acute heat stress induces differential protein expression in the hypothalami of the L2 strain Taiwan country chickens, which may manifest detrimental effects. Furthermore, differential expression is a critical response in the hypothalamus for the regulation of thermotolerance.

The phylogenetic and recombinational analysis of beak and feather disease virus Taiwan isolates.

Beak and feather disease virus (BFDV) is an avian circovirus, and it has a single-stranded DNA genome. It causes a fatal disease in parrots called psittacine beak and feather disease (PBFD). After screening of samples collected from Taiwan using PCR, complete genome sequences of isolates from 21 samples from various species of parrot were obtained. The nucleotide sequences of the replication-associated protein gene (rep) and the amino acid sequences of the replication-associated protein (Rep) were more conserved than the nucleotide sequences of the capsid protein gene (cp) and the amino acid sequences of the capsid protein (CP). In Bayesian phylogenetic analysis, the topology of the complete genome sequence was similar to that of the rep gene alone. Recombination events were identified in Taiwan isolates. Recombination hot spots were mainly located in the intergenic region between the 3' ends of the rep and cp genes and at the 5' end of the cp gene. The 5' end and the middle of the rep gene were found to be recombination cold spots. Despite the overall negative selection that was observed for the rep and cp genes, one and 18 positive selected sites were found for the rep and cp gene, respectively.

Let-7-mediated suppression of mucin 1 expression in the mouse uterus during embryo implantation.

Mucin 1 (Muc1) is an integral transmembrane mucin glycoprotein expressed on the apical surface of most epithelia. It is considered to be a barrier to the regulation of embryo implantation by inhibiting attachment of the embryo to the endometrium. Therefore, loss of Muc1 on the surface of uterine epithelial cells is necessary for embryo implantation. Studies have demonstrated that microRNAs (miRNAs) play a key role in enhancing embryo implantation in mammals. In this study, we investigated the regulatory role of two miRNAs (let-7a and let-7b) on the expression of Muc1 in mouse uteri during implantation. Western blotting indicated that Muc1 expression was highest on day1 of pregnancy and constantly decreased thereafter until day 4. In contrast to Muc1 expression, increased expression of let-7a and let-7b was evident on day 4 of pregnancy as measured by real-time reverse transcription-polymerase chain reaction (real-time RT-PCR). We demonstrated direct binding of let-7a and let-7b to the 3'untranslated region of muc1. Furthermore, Muc1 expression was suppressed after transfection of mouse uterine epithelial cells isolated from day 1 of pregnancy with let-7a and let-7b. In summary, the present study provides evidence that Muc1 is a direct target of let-7a and let-7b. Additionally, the current study suggests that miRNAs are novel targets which can be used to facilitate a successful pregnancy and repair implantation failure.

MicroRNA-199a mediates mucin 1 expression in mouse uterus during implantation.

Embryo implantation is a complicated process involving interactions between the blastocyst and the luminal epithelium of the receptive uterus. Mucin 1 (MUC1) is an integral membrane glycoprotein expressed apically by secretory epithelial cells and the glandular epithelium in different organs, including the uterus. It is believed that loss of MUC1 on the surface of uterine epithelial cells is necessary for embryo implantation. The endogenous non-protein coding microRNAs (miRNAs) of 21-24 nucleotides are found in diverse organisms. It has been shown that miRNAs participate in a range of cellular processes by regulating gene expression at the post-transcriptional level. In the present study, the regulatory role of miRNA-199a on the expression of MUC1 in mouse uterus during implantation was investigated for its effect on embryo implantation. Western blotting and immunohistochemistry results showed high MUC1 expression on Day 0.5 and low expression by Day 4.5 of pregnancy. In contrast with MUC1 expression, increased miRNA-199a expression was evident at Day 4.5 of pregnancy, as measured by real-time reverse transcription-polymerase chain reaction. In addition, we demonstrated direct binding of miRNA-199a to the 3'-untranslated region of MUC1. Transfection of miRNA-199a into mouse uterine epithelial cells isolated from Day 0.5 of pregnancy also downregulated expression of MUC1. Therefore, the present study provides evidence that MUC1 is a direct target of miRNA-199a and suggests that development of novel strategies to facilitate a successful pregnancy and repair implantation failure humans may include miRNA.

Improving the meiotic competence of small antral follicle-derived porcine oocytes by using dibutyryl-cAMP and melatonin.

OBJECTIVE: We increased the nuclear maturation rate of antral follicle derived oocytes by using a pre-in vitro maturation (IVM) culture system and improved the developmental potential of these porcine pathenotes by supplementing with melatonin. Furthermore, we investigated the expression patterns of genes involved in cumulus expansion (HAS2, PTGS2, TNFAIP6, and PTX3) derived from small and medium antral follicles before and after oocyte maturation. METHODS: Only the cumulus oocyte-complexes (COCs) derived from small antral follicles were induced with [Pre-SF(+)hCG] or without [Pre-SF(-)hCG] the addition of human chorionic gonadotropin (hCG) during the last 7 h of the pre-IVM period before undergoing the regular culture system. The mature oocytes were investigated on embryonic development after parthenogenetic activation (PA). Melatonin (10-7 M) was supplemented during in vitro culture (IVC) to improve the developmental potential of these porcine pathenotes. RESULTS: A pre-IVM culture system with hCG added during the last 7 h of the pre-IVM period [Pre-SF(+)hCG] effectively supported small antral follicle-derived oocytes and increased their nuclear maturation rate. The oocytes derived from medium antral follicles exhibited the highest nuclear maturation rate in a regular culture system. Compared with oocytes cultured in a regular culture system, those cultured in the pre-IVM culture system exhibited considerable overexpression of HAS2, PTGS2, and TNFAIP6. Porcine embryos treated with melatonin during IVC exhibited markedly improved quality and developmental competence after PA. Notably, melatonin supplementation during the IVM period can reduce and increase the levels of intracellular reactive oxygen species (ROS) and glutathione (GSH), respectively. CONCLUSION: Our findings indicate that the Pre-SF(+)hCG culture system increases the nuclear maturation rate of small antral follicle-derived oocytes and the expression of genes involved in cumulus expansion. Melatonin supplementation during IVC may improve the quality and increase the blastocyst formation rate of porcine embryos. In addition, it can reduce and increase the levels of ROS and GSH, respectively, in mature oocytes, thus affecting subsequent embryos.

Influence of sex hormones on the aggressive behavior during peck order establishment and stabilization in meat and egg type chickens.

In the poultry industry, broiler and layer strains are genetically selected for different purposes (e.g., high meat-yield and high egg-production). Genetic selection for productivity can have unintended consequences on the behavioral repertoire of the birds, including aggression. Alongside the increasing societal concern regarding the welfare of animal in agriculture, the number of countries that are advocating the prohibition of using battery cages for laying hens has resulted in the transition and adoption of cage-free or free-range systems. Thus, both broiler and layer chickens are housed in large flocks rather than housed individually in cages. Housing birds in groups increases the opportunity for birds to engage in social behaviors, including aggression, that are used to establish social status. Aggressive interactions are associated with the risk of injury and the potential for a subordinate animal to have unmet needs (e.g., access to feed). The aim of this study was to characterize the relationships among aggressive behavior, neurobiology, and hormones during peck order establishment and social hierarchy stabilization of 2 divergently selected strains (meat- and egg-type chicken). Meat-type strains performed more male on male (P < 0.001), male on female (P < 0.0001), and female on female (P < 0.0001) non-reciprocal aggression behavior (NRA) than egg-type strains. Greater serum testosterone and estradiol concentrations in the weeks after the peck order establishment were observed in meat-type birds compared those in egg-type birds for both males and females (all P < 0.05). Greater (P < 0.05) cellular densities of androgen receptors, but not estrogen receptors, were observed in the hypothalamus of meat-type birds compared to egg-type birds. These findings suggest that greater sex hormone concentrations in the meat-type birds may be a consequence of genetic selection for rapid growth resulting in more sex hormones-induced aggressive behavior.

Impact of metformin on neocortical development during pregnancy: Involvement of ERK and p35/CDK5 pathways.

Metformin, the most commonly prescribed drug for the treatment of diabetes, is increasingly used during pregnancy to address various disorders such as diabetes, obesity, preeclampsia, and metabolic diseases. However, its impact on neocortex development remains unclear. Here, we investigated the direct effects of metformin on neocortex development, focusing on ERK and p35/CDK5 regulation. Using a pregnant rat model, we found that metformin treatment during pregnancy induces small for gestational age (SGA) and reduces relative cortical thickness in embryos and neonates. Additionally, we discovered that metformin inhibits neural progenitor cell proliferation in the sub-ventricular zone (SVZ)/ventricular zone (VZ) of the developing neocortex, a process possibly mediated by ERK inactivation. Furthermore, metformin induces neuronal apoptosis in the SVZ/VZ area of the developing neocortex. Moreover, metformin retards neuronal migration, cortical lamination, and differentiation, potentially through p35/CDK5 inhibition in the developing neocortex. Remarkably, compensating for p35 through in utero electroporation partially rescues metformin-impaired neuronal migration and development. In summary, our study reveals that metformin disrupts neocortex development by inhibiting neuronal progenitor proliferation, neuronal migration, cortical layering, and cortical neuron maturation, likely via ERK and p35/CDK5 inhibition. Consequently, our findings advocate for caution in metformin usage during pregnancy, given its potential adverse effects on fetal brain development.

Bone Morphogenetic Protein 15 (BMP-15) Improves In Vitro Mouse Folliculogenesis.

Multilayered secondary follicles were encapsulated in a 0.5% alginate matrix and cultured in a 3D culture system supplemented with bone morphogenetic protein 15 (BMP-15; 15 ng/mL) for 12 days. The in vitro development of ovarian follicles was evaluated. On day 12, the follicle diameter, follicle survival rate, and antrum formation rate were significantly higher for follicles cultured in BMP-15-supplemented medium than those cultured in regular medium. The percentage of ovulated metaphase II oocytes retrieved from follicles cultured in BMP-15-supplemented medium was greater than that of oocytes retrieved from follicles cultured in regular medium. The secretion of P4 was significantly higher on days 6, 8, and 10 in follicles cultured in BMP-15-supplemented medium. The result for E2 tended toward significance on day 12. Intracellular reactive oxygen species levels were higher and glutathione levels were lower in mature oocytes from the in vitro culture than in mature oocytes from an in vivo control. A 3D culture system using an alginate matrix and supplemented with BMP-15 effectively improves the outcomes of in vitro ovarian follicle culture.

Comparison of Immune-Related Gene Expression in Two Chicken Breeds Following Infectious Bronchitis Virus Vaccination.

This study aims to identify the immune-related genes and the corresponding biological pathways following infectious bronchitis virus vaccination in Taiwan Country and White Leghorn chicken breeds. Transcriptomic analyses of the spleen of these two breeds were conducted by next-generation sequencing. Compared to White Leghorn chicken, Taiwan Country chicken showed a significantly higher level of anti-infectious bronchitis virus (IBV) antibodies at 14 and 21 days pos vaccination. At 7 days post vaccination, in the Taiwan Country chicken, higher expression of mitogen-activated protein kinase 10, Major histocompatibility complex class 1, and V-set pre-B cell surrogate light chain 3 were found. In contrast, the White Leghorn chicken had a high expression of interleukin 4 induced 1, interleukin 6, and interleukin 22 receptor subunit alpha 2. These findings have highlighted the variations in immune induction between chickens with distinct genetic background and provided biological pathways and specific genes involved in immune responses against live attenuated IBV vaccine.

Bioimpedance-Measurement-Based Non-Invasive Method for In Ovo Chicken Egg Sexing.

Day-old male chick culling is one of the world's most inhumane problems in the poultry industry. Every year, seven billion male chicks are slaughtered in laying-hen hatcheries due to their higher feed exchange rate, lower management than female chicks, and higher production costs. This study describes a novel non-invasive method for determining the gender of chicken eggs. During the incubation period of fourteen days, four electrodes were attached to each egg for data collection. On the last day of incubation, a standard polymerase chain reaction (PCR)-based chicken gender determination protocol was applied to the eggs to obtain the gender information. A relationship was built between the collected data and the egg's gender, and it was discovered to have a reliable connection, indicating that the chicken egg gender can be determined by measuring the impedance data of the eggs on day 9 of incubation with the four electrodes set and using the self-normalization technique. This is a groundbreaking discovery, demonstrating that impedance spectroscopy can be used to sex chicken eggs before they hatch, relieving the poultry industry of such an ethical burden.

Let-7b-mediated suppression of basigin expression and metastasis in mouse melanoma cells.

Basigin (Bsg), also called extracellular matrix metalloproteinase inducer (EMMPRIN), is highly expressed on the surface of tumor cells and stimulates adjacent fibroblasts or tumor cells to produce matrix metalloproteinases (mmps). It has been shown that Bsg plays an important role in growth, development, cell differentiation, and tumor progression. MicroRNAs (miRNAs) are a class of short endogenous non-protein coding RNAs of 20-25 nucleotides (nt) that function as post-transcriptional regulators of gene expression by base-pairing to their target mRNAs and thereby mediate cleavage of target mRNAs or translational repression. In this study, let-7b, one of the let-7 family members, was investigated for its effect on the growth and invasiveness of the mouse melanoma cell line B16-F10. We have shown that let-7b can suppress the expression of Bsg in B16-F10 cells and also provided evidence that this suppression could result in the indirect suppression of mmp-9. The ability of B16-F10 cells transfected with let-7b to invade or migrate was significantly reduced. In addition, let-7b transfected B16-F10 cells displayed an inhibition of both cellular proliferation and colony formation. Furthermore, it was shown that the overexpression of let-7b in B16-F10 cells could reduce lung metastasis. Taken together, the present study identifies let-7b as a tumor suppressor that represses cancer cell proliferation and migration as well as tumor metastasis in mouse melanoma cells.

Genome Assembly and Evolutionary Analysis of the Mandarin Duck Aix galericulata Reveal Strong Genome Conservation among Ducks.

The mandarin duck, Aix galericulata, is popular in East Asian cultures and displays exaggerated sexual dimorphism, especially in feather traits during breeding seasons. We generated and annotated the first mandarin duck de novo assembly, which was 1.08 Gb in size and encoded 16,615 proteins. Using a phylogenomic approach calibrated with fossils and molecular divergences, we inferred that the last common ancestor of ducks occurred 13.3-26.7 Ma. The majority of the mandarin duck genome repetitive sequences belonged to the chicken repeat 1 (CR1) retroposon CR1-J2_Pass, which underwent a duck lineage-specific burst. Synteny analyses among ducks revealed infrequent chromosomal rearrangements in which breaks were enriched in LINE retrotransposons and DNA transposons. The calculation of the dN/dS ratio revealed that the majority of duck genes were under strong purifying selection. The expanded gene families in the mandarin duck are primarily involved in olfactory perception as well as the development and morphogenesis of feather and branching structures. This new reference genome will improve our understanding of the morphological and physiological characteristics of ducks and provide a valuable resource for functional genomics studies to investigate the feather traits of the mandarin duck.