Biology Open最新文献

In this study, we established bovine embryonic stem cell (bESC) lines from early (eBL) and full (BL) blastocysts to determine the efficiency of bESC derivation from an earlier embryonic stage and compare the characteristics of the resulting lines. Using established medium and protocols for derivation of primed bESCs from expanded blastocysts, we derived bESC lines from eBLs and BLs with the same efficiency (4/12 each, 33%). Regardless of original blastocyst stage, bESC lines had a similar phenotype, including differentiation capacity, stable karyotype, and pluripotency marker expression over feeder-free transition and long-term culture. Transcriptome and functional analyses indicated that eBL- and BL-derived lines were in primed pluripotency. We additionally compared RNA-sequencing data from our lines to bovine embryos and stem cells from other recent reports, finding that base medium was the predominant source of variation among cell lines. In conclusion, our results show that indistinguishable bESC lines can be readily derived from eBL and BL, widening the pool of embryos available for bESC establishment. Finally, our investigation points to sources of variation in cell phenotype among recently reported bESC conditions, opening the door to future studies investigating the impact of factors aside from signaling molecules on ESC derivation, maintenance, and performance.

The five-subunit endosomal Rab5 and RNA/ribose intermediary (FERRY) complex is a newly described protein complex consisting of TBCK, PPP1R21, FERRY3 (previously C12orf4), CRYZL1, and GATD1. The FERRY complex is proposed to function as a Rab5 effector to shuttle mRNA to the cell periphery for local translation, a process especially important in cells with far reaching processes. Interestingly, three members of the FERRY complex are associated with ultra-rare neurogenetic disorders. Mutation of TBCK causes TBCK syndrome, mutation of PPP1R21 is associated with PPP1R21-related intellectual disability, and mutation of FERRY3 results in an autosomal recessive intellectual disability. Neurologic disorders have yet to be associated with mutation of GATD1 or CRYZL1. Here, we provide a review of each FERRY complex-related neurologic disorder and draw clinical comparisons between the disease states. We also discuss data from the current cellular and animal models available to study these disorders, which is notably disparate and scattered across different cell types and systems. Taken together, we explore the possibility that these three diseases may represent one shared disease class, which could be further understood by combining and comparing known information about each individual disease. If true, this could have substantial implications on our understanding of the cellular role of the FERRY complex and on treatment strategies for affected individuals, allowing researchers, clinicians, and patient organizations to maximize the utility of research efforts and resources to support patients with these disorders.

During embryonic development vascular endothelial and hematopoietic cells are thought to originate from a common precursor, the hemangioblast. An evolutionarily conserved ETS transcription factor FLI1 has been previously implicated in the hemangioblast formation and hematopoietic and vascular development. However, its role in regulating hemangioblast transition into hematovascular lineages is still incompletely understood. Its zebrafish paralog Fli1b functions partially redundantly with an ETS transcription factor Etv2 / Etsrp during vasculogenesis and angiogenesis. However, its role in embryonic hematopoiesis has not been previously investigated. Here we show that zebrafish fli1b mutants have a reduced formation of primitive erythrocytes and hematopoietic stem and progenitor cells, and display reduced expression of key regulators of hematopoiesis, including scl / tal1, gata1 and runx1. Expression of scl / tal1 was sufficient to partially rescue defects in erythroid differentiation in fli1b mutants, arguing that scl functions downstream of fli1b during primitive erythropoiesis. In addition, myelopoiesis was strongly misregulated in fli1b mutants. While the formation of the earliest myeloid progenitors, neutrophils and macrophages, was greatly reduced in fli1b mutants, this was compensated by the increased emergence of the myeloid cells from the alternative hematopoietic site, the endocardium. Intriguingly, myeloid cells in fli1b mutants retained vascular endothelial marker expression, suggesting that they are present in hemangioblast-like state. In summary, our results demonstrate a novel role of fli1b transcription factor in regulating embryonic hematopoiesis.

The Integrator is a metazoan-conserved protein complex with endonuclease activity that functions to cleave various RNA substrates to shape transcriptome homeostasis by coordinating small nuclear RNA biogenesis to premature transcription termination. Depletion of Integrator results in developmental defects across different model systems and has emerged as a causative factor in human neurodevelopmental syndromes. Here, we use the model system Caenorhabditis elegans to enable studying the temporal effects of Integrator depletion on various physiological parameters with the auxin-inducible degron system that permitted depletion of INTS-4 (Integrator subunit) catalytic subunit of the protein complex. We found that Integrator activity is critical and required for C. elegans development within the L1 larval stage, but becomes dispensable for development and lifespan after the animals have reached the L2/L3 stage. Depletion of INTS-4 only shortened lifespan if auxin was introduced at the L1 stage, suggesting that the previously described lifespan reduction by Integrator inhibition is linked to developmental growth defects. We also found that while germline-specific degradation of Integrator results in the accumulation of misprocessed snRNA transcript, it did not impair the development or lifespan but surprisingly increased progeny production. Together, our study illustrates a temporal, and a potential tissue-specific requirement of the Integrator complex function in shaping whole organism development, aging, and reproduction.

Antipredation behaviour is of high importance for the survival of prey animals, but it is also vital for the predator to understand the antipredator behaviour of potentially dangerous prey. Venomous snakes are particularly dangerous for their predators and humans, as a defensive bite may result in death. Here we studied the behavioural response of the Mexican pigmy rattlesnake Crotalus ravus to the approach of simulated predators (birds and fox) and human, contrasting this to their predatory behaviour. Results showed that C. ravus defensive behaviour depended on the predator and was more aggressive towards humans. Mostly, for each type of behaviour the approach distance at first occurrence, was similar among trials with different predators and reduced from freezing>rattling>escape>bite. However, we did not find clear behavioural patterns. In bird and fox trials, snakes always rattled or escaped before biting, however warning signals were not always displayed before biting and bite frequency was high in human trials, suggesting that this snake is dangerous for humans. Our results demonstrate that these snakes are flexible in their response to potential threats, but that approach distance that elicit specific behaviours are mostly fixed.

As cells transition between periods of growth and quiescence, their metabolic demands change. During this transition, cells must coordinate changes in mitochondrial function with the induction of biosynthetic processes. Mitochondrial metabolism and nucleotide biosynthesis are key rate-limiting factors in regulating early growth. However, it remains unclear what coordinates these mechanisms in developmental systems. Here, we show that during quiescence, as mitochondrial activity drops, nucleotide breakdown increases. However, at fertilization, mitochondrial oxidative metabolism and nucleotide biosynthesis are coordinately activated to support early embryogenesis. We have found that the serine/threonine kinase GSK3 is a key factor in coordinating mitochondrial metabolism with nucleotide biosynthesis during transitions between quiescence and growth. Silencing GSK3 in quiescent oocytes causes increased levels of mitochondrial activity and a shift in the levels of several redox metabolites. Interestingly, silencing GSK3 in quiescent oocytes also leads to a precocious induction of nucleotide biosynthesis in quiescent oocytes. Taken together, these data indicate that GSK3 functions to suppress mitochondrial oxidative metabolism and prevent the premature onset of nucleotide biosynthesis in quiescent eggs. These data reveal a key mechanism that coordinates mitochondrial function and nucleotide synthesis with fertilization.

The green synthesis of metal nanoparticles has garnered significant attention due to its simplicity, cost-effectiveness, and environmental sustainability. Gold nanoparticles (AuNPs) and silver nanoparticles (AgNPs) are widely employed across various industries, agriculture, and medicine owing to their unique physicochemical properties. This study explores the feasibility of synthesizing metal nanoparticles through green methods using ethanolic (70%) extracts from Artemisia annua hairy roots. These extracts were found to contain reducing agents, primarily phenolic compounds, as identified by HPLC and MALDI-MS analyses. The phenolic compounds included hydroxybenzoic acids (e.g., p-coumaric and gallic acids) and hydroxycinnamic acids (e.g., caffeic acid and its derivatives such as chlorogenic, dicaffeoylquinic, and rosmarinic acids). The synthesis and structural characteristics of AuNPs and AgNPs were systematically compared. AgNPs formed a stable colloidal solution over extended periods, while AuNPs exhibited instability due to significant nanoparticle aggregation and precipitation. Furthermore, the photocatalytic activities of these nanoparticles in the degradation of methylene blue were evaluated. AuNPs demonstrated substantial photocatalytic activity, whereas AgNPs exhibited negligible catalytic effects. This study highlights the potential and limitations of A. annua hairy root extracts in the biosynthesis of AuNPs and AgNPs, providing insights into their structural and functional differences.

Animal vocalizations can evolve structural features as long-term adaptations to noisy environments. Using such signals, cetaceans could mitigate masking from vessel noise. This study investigates whether beluga whales (Delphinapterus leucas) use ultrasonic high-frequency burst pulse (HFBP) calls to communicate in noisy conditions. We identified HFBP calls in three populations: St. Lawrence Estuary, Eastern High Arctic-Baffin Bay, and Western Hudson Bay. Focusing on the industrialized St. Lawrence, we investigated the effects of vessel noise on HFBP call rates compared to other call types. Ultrasonic calls, spanning a bandwidth of 36.4±6.5 to 144 kHz (Nyquist frequency), comprised 13% of the St. Lawrence beluga repertoire (n=25,435). Noise events (n=21) were defined as periods when at least one vessel was visible within 2 km of the hydrophone while belugas were within 500 m. Sound pressure levels were measured before, during, and after exposure. Generalized linear mixed models revealed consistent HFBP call rates before, during, and after vessel noise exposure, while contact calls and other call types declined during exposure (n=4,528). These findings suggest that ultrasonic signals that evolved in the Arctic-where ice-associated noise may have created a need for high-frequency communication-remain a viable communication channel in vessel noise, allowing belugas to exploit these signals to maintain communication. Understanding how belugas utilize signals in noisy environments can inform conservation strategies for noise-impacted marine mammals.

Focal adhesion protein, paxillin plays an important role in embryonic development. We have reported that paxillin controls directional cell motility and angiogenesis. The role of paxillin in lung development remains unclear. Paxillin expression is higher in mouse pulmonary alveolar epithelial type 2 (AT2) cells at postnatal day (P)10 (alveolar stage) compared to P0 (saccular stage). The alveolar and vascular structures are disrupted, lung compliance is reduced, and the postnatal survival rate is lower in tamoxifen-induced PxniΔAT2 neonatal mice, in which the levels of paxillin in AT2 cells are knocked down. Surfactant protein expression and lamellar body structure are also inhibited in PxniΔAT2 neonatal mouse lungs. The expression of lipid transporter ABCA3 and its transcriptional regulator CEBPA that control surfactant homeostasis is inhibited in PxniΔAT2 neonatal mouse AT2 cells. These findings suggest that paxillin controls lung alveolar development through CEBPA-ABCA3 signaling in AT2 cells. Modulation of paxillin in AT2 cells may be novel interventions for neonatal lung developmental disorder.

Hovering flight helps facilitate feeding, pollination, and courtship. Observed only for smaller flying animals, the hover kinematic characteristics are diverse except for the decreasing flapping frequency with the animal size. Although studies have shown that these wing patterns enable distinct unsteady aerodynamic mechanisms, the role of flapping frequency scaling remains a source of disagreement. Here we show that negative allometry of the flapping frequency is required to sustain body attitude during hovering, consistent with the experimental data of hovering animals from fruit flies to hummingbirds reported in the literature. The derived scaling model reveals that the lift coefficient and reduced frequency remain invariant with mass, enabling leading-edge vortex formation and wake-capture for a wide range of fliers to hover.