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Common carp ( Cyprinus carpio ) is an allotetraploid species derived from recent whole genome duplication and provides a model to study polyploid genome evolution in vertebrates. Here, we generate three chromosome-level reference genomes of C. carpio and compare to related diploid Cyprinid genomes. We identify a Barbinae lineage as potential diploid progenitor of C. carpio and then divide the allotetraploid genome into two subgenomes marked by a distinct genome similarity to the diploid progenitor. We estimate that the two diploid progenitors diverged around 23 Mya and merged around 12.4 Mya based on the divergence rates of homoeologous genes and transposable elements in two subgenomes. No extensive gene losses are observed in either subgenome. Instead, we find gene expression bias across surveyed tissues such that subgenome B is more dominant in homoeologous expression. CG methylation in promoter regions may play an important role in altering gene expression in allotetraploid C. carpio . The common carp is derived from recent whole genome duplication and represents a model for polyploid genome evolution, rare in vertebrates. Here, the authors generate and analyse chromosome-level reference genomes for common carp, and describe subgenome gene expression changes.

In the context of the continuous degradation of the global environment, ecological restoration has become a primary task in global environmental governance. In this process, remote sensing technology, as an advanced monitoring and analysis tool, plays a key role in monitoring ecological restoration. This article reviews the application of remote sensing technology in ecological restoration monitoring. Based on a comprehensive analysis of the literature in the field of ecological remote sensing, it systematically summarizes the major in-orbit spaceborne and airborne sensors and their related products. This article further proposes a series of evaluation indicators for ecological restoration from four aspects: forests, soil, water, and the atmosphere, and elaborates on the calculation methods for these indicators. In addition, this paper also summarizes the methods for evaluating the effectiveness of ecological restoration, including subjective evaluation, objective evaluation, and comprehensive evaluation methods. Finally, we analyze the challenges faced by remote sensing technology in evaluating ecological restoration effectiveness, such as issues with the precision of indicators extraction, the limitations of spatial resolution, and the diversity of evaluation methods. This review also looks forward to future ecological restoration technologies, such as the potential applications of integrated aerospace and terrestrial remote sensing, multi-data fusion, and machine learning technologies. This study reveals the effectiveness of remote sensing technology in ecological restoration monitoring, aiming to provide efficient tools and innovative strategies for future remote sensing monitoring and assessment of ecological restoration.

The water components affecting turbidity are complex and changeable, and the spectral response mechanism of each water quality parameter is different. Therefore, this study mainly aimed at the turbidity monitoring by unmanned aerial vehicle (UAV) hyperspectral technology, and establishes a set of turbidity retrieval models through the artificial control experiment, and verifies the model’s accuracy through UAV flight and water sample data in the same period. The results of this experiment can also be extended to different inland waters for turbidity retrieval. Retrieval of turbidity values of small inland water bodies can provide support for the study of the degree of water pollution. We collected the images and data of aquaculture ponds and irrigation ditches in Dawa District, Panjin City, Liaoning Province. Twenty-nine standard turbidity solutions with different concentration gradients (concentration from 0 to 360 NTU—the abbreviation of Nephelometric Turbidity Unit, which stands for scattered turbidity.) were established through manual control and we simultaneously collected hyperspectral data from the spectral values of standard solutions. The sensitive band to turbidity was obtained after analyzing the spectral information. We established four kinds of retrieval, including the single band, band ratio, normalized ratio, and the partial least squares (PLS) models. We selected the two models with the highest R2 for accuracy verification. The band ratio model and PLS model had the highest accuracy, and R2 was, respectively, 0.65 and 0.72. The hyperspectral image data obtained by UAV were combined with the PLS model, which had the highest R2 to estimate the spatial distribution of water turbidity. The turbidity of the water areas in the study area was 5–300 NTU, and most of which are 5–80 NTU. It shows that the PLS models can retrieve the turbidity with high accuracy of aquaculture ponds, irrigation canals, and reservoirs in Dawa District of Panjin City, Liaoning Province. The experimental results are consistent with the conclusions of the field investigation.

The rapid advancement of remote sensing technology has significantly enhanced the temporal resolution of remote sensing data. Multitemporal remote sensing image classification can extract richer spatiotemporal features. However, this also presents the challenge of mining massive data features. In response to this challenge, deep learning methods have become prevalent in machine learning and have been widely applied in remote sensing due to their ability to handle large datasets. The combination of remote sensing classification and deep learning has become a trend and has developed rapidly in recent years. However, there is a lack of summary and discussion on the research status and trends in multitemporal images. This review retrieved and screened 170 papers and proposed a research framework for this field. It includes retrieval statistics from existing research, preparation of multitemporal datasets, sample acquisition, an overview of typical models, and a discussion of application status. Finally, this paper discusses current problems and puts forward prospects for the future from three directions: adaptability between deep learning models and multitemporal classification, prospects for high-resolution image applications, and large-scale monitoring and model generalization. The aim is to help readers quickly understand the research process and application status of this field.

The combination of genome editing and primordial germ cell (PGC) transplantation has enormous significance in the study of developmental biology and genetic breeding, despite its low efficiency due to limited number of donor PGCs. Here, we employ a combination of germplasm factors to convert blastoderm cells into induced PGCs (iPGCs) in zebrafish and obtain functional gametes either through iPGC transplantation or via the single blastomere overexpression of germplasm factors. Zebrafish-derived germplasm factors convert blastula cells of Gobiocypris rarus into iPGCs, and Gobiocypris rarus spermatozoa can be produced by iPGC-transplanted zebrafish. Moreover, the combination of genome knock-in and iPGC transplantation perfectly resolves the contradiction between high knock-in efficiency and early lethality during embryonic stages and greatly improves the efficiency of genome knock-in. Together, we present an efficient method for generating PGCs in a teleost, a technique that will have a strong impact in basic research and aquaculture. Primordial germ cell (PGC) transplantation is an important technology for developmental biology and genetic breeding. Here, Wang et al. develop an approach for PGC induction that enhances the efficiency of PGC transplantation in zebrafish.

The Wnt/β-catenin signaling pathway plays key roles in development and adult tissue homeostasis by controlling cell proliferation and cell fate decisions. TCF/LEF transcription factors play a pivotal role in this pathway, acting as repressors by recruiting co-repressors in the absence of Wnt signals, and as activators via β-catenin binding in the presence of Wnt signaling. While progress has been made in our understanding of Wnt signaling regulation, the underlying mechanism that regulates the protein stability of the TCF/LEF family is far less clear. Using cultured cells and zebrafish as in vitro and in vivo models, we demonstrated that the von Hippel-Lindau protein (pVHL), the substrate recognition component of an E3 ubiquitin ligase complex, regulates the stability of TCF/LEF proteins. Unexpectedly, pVHL directly binds to TCF/LEF and promotes their proteasomal degradation independent of its E3 ubiquitin ligase activity. Notably, a human homologue of pVHL, the pVHL-like protein (pVHLL), which lacks the capability to assemble an E3 ligase complex with Elongin B/C, RBX1, and CUL2, similarly downregulates TCF/LEF protein levels. Knockout of vhl in zebrafish embryos leads to a reduction of dorsal habenular neurons and this effect is upstream of dorsal habenular neurons phenotype in tcf7l2 -null mutants. Our study uncovers a previously unknown mechanism for the protein stability regulation of TCF/LEF transcription factors and demonstrates that pVHL contains a 26S proteasome binding domain that drives ubiquitin-independent proteasomal degradation. These findings provide new insights into the ubiquitin-independent function of pVHL and uncover a novel mechanistic regulation of Wnt/β-catenin signaling.

Teleost sex differentiation largely depends on the number of undifferentiated germ cells. Here, we describe the generation and characterization of a novel transgenic zebrafish line, Tg(piwil1:egfp-UTRnanos3)ihb327Tg, which specifically labels the whole lifetime of germ cells, i.e., from primordial germ cells (PGCs) at shield stage to the oogonia and early stage of oocytes in the ovary and to the early stage of spermatogonia, spermatocyte, and spermatid in the testis. By using this transgenic line, we carefully observed the numbers of PGCs from early embryonic stage to juvenile stage and the differentiation process of ovary and testis. The numbers of PGCs became variable at as early as 1 day post-fertilization (dpf). Interestingly, the embryos with a high amount of PGCs mainly developed into females and the ones with a low amount of PGCs mainly developed into males. By using transient overexpression and transgenic induction of PGC-specific bucky ball (buc), we further proved that induction of abundant PGCs at embryonic stage promoted later ovary differentiation and female development. Taken together, we generate an ideal transgenic line Tg(piwil1:egfp-UTRnanos3)ihb327Tg which can visualize zebrafish germline for a lifetime, and we have utilized this line to study germ cell development and gonad differentiation of teleost and to demonstrate that the increase of PGC number at embryonic stage promotes female differentiation.

Inland waters consist of multiple concentrations of constituents, and solving the interference problem of chlorophyll-a and colored dissolved organic matter (CDOM) can help to accurately invert total suspended matter concentration (Ctsm). In this study, according to the characteristics of the Multispectral Imager for Inshore (MII) equipped with the first Sustainable Development Goals Science Satellite (SDGSAT-1), an iterative inversion model was established based on the iterative analysis of multiple linear regression to estimate Ctsm. The Hydrolight radiative transfer model was used to simulate the radiative transfer process of Lake Taihu, and it analyzed the effect of three component concentrations on remote sensing reflectance. The characteristic band combinations B6/3 and B6/5 for multiple linear regression were determined using the correlation of the three component concentrations with different bands and band combinations. By combining the two multiple linear regression models, a complete closed iterative inversion model for solving Ctsm was formed, which was successfully verified by using the modeling data (R2 = 0.97, RMSE = 4.89 g/m3, MAPE = 11.48%) and the SDGSAT-1 MII image verification data (R2 = 0.87, RMSE = 3.92 g/m3, MAPE = 8.13%). And it was compared with iterative inversion models constructed based on other combinations of feature bands and other published models. Remote sensing monitoring Ctsm was carried out using SDGSAT-1 MII images of Lake Taihu in 2022–2023. This study can serve as a technical reference for the SDGSAT-1 satellite in terms of remote sensing monitoring of Ctsm, as well as monitoring and improving the water environment.

Although the metabolism of yolk lipids such as docosahexaenoic acid (DHA) is pivotal for embryonic development, the underlying mechanism remains elusive. Here we find that the zebrafish hydroxysteroid (17-β) dehydrogenase 12a ( hsd17b12a ), which encodes an intestinal epithelial-specific enzyme, is essential for the biosynthesis of long-chain polyunsaturated fatty acids in primitive intestine of larval fish. The deficiency of hsd17b12a leads to severe developmental defects in the primitive intestine and exocrine pancreas. Mechanistically, hsd17b12a deficiency interrupts DHA synthesis from essential fatty acids derived from yolk-deposited triglycerides, and consequently disrupts the intestinal DHA-phosphatidic acid (PA)-phosphatidylglycerol (PG) axis. This ultimately results in developmental defects of digestive organs, primarily driven by ferroptosis. Our findings indicate that the DHA-PA-PG axis in the primitive intestine facilitates the uptake of yolk lipids and promotes the expansion of digestive organs, thereby uncovering a mechanism through which DHA regulates embryonic development. Lipid utilization from the yolk sac plays a crucial role in embryonic development. Here, Chen et al. generate hsd17b12a mutant zebrafish and discover that a docosahexaenoic acid (DHA)-phosphatidic acid (PA)-phosphatidylglycerol (PG) (DHA-PA-PG) axis facilitates the uptake of yolk lipids and promotes the expansion of digestive organs.

Maternal β-catenin activity is essential and critical for dorsal induction and its dorsal activation has been thoroughly studied. However, how the maternal β-catenin activity is suppressed in the nondorsal cells remains poorly understood. Nanog is known to play a central role for maintenance of the pluripotency and maternal -zygotic transition (MZT). Here, we reveal a novel role of Nanog as a strong repressor of maternal β-catenin signaling to safeguard the embryo against hyperactivation of maternal β-catenin activity and hyperdorsalization. In zebrafish, knockdown of nanog at different levels led to either posteriorization or dorsalization, mimicking zygotic or maternal activation of Wnt/β-catenin activities, and the maternal zygotic mutant of nanog (MZnanog) showed strong activation of maternal β-catenin activity and hyperdorsalization. Although a constitutive activator-type Nanog (Vp16-Nanog, lacking the N terminal) perfectly rescued the MZT defects of MZnanog, it did not rescue the phenotypes resulting from β-catenin signaling activation. Mechanistically, the N terminal of Nanog directly interacts with T-cell factor (TCF) and interferes with the binding of β-catenin to TCF, thereby attenuating the transcriptional activity of β-catenin. Therefore, our study establishes a novel role for Nanog in repressing maternal β-catenin activity and demonstrates a transcriptional switch between β-catenin/TCF and Nanog/TCF complexes, which safeguards the embryo from global activation of maternal β-catenin activity.