Abstract
Androgen is essential for male development and cortisol is involved in reproduction in fishes. However, the in vivo roles of cortisol and specific androgens such as 11-ketotestosterone ...(11-KT) in reproductive development need to be described with genetic models. Zebrafish cyp11c1 encodes 11β-hydroxylase, which is essential for the biosynthesis of 11-KT and cortisol. In this study, we generated a zebrafish mutant of cyp11c1 (cyp11c1-/-) and utilized it to clarify the roles of 11-KT and cortisol in sexual development and reproduction. The cyp11c1-/- fish had smaller genital papilla and exhibited defective natural mating but possessed mature gametes and were found at a sex ratio comparable to the wildtype control. The cyp11c1-/- males showed delayed and prolonged juvenile ovary-to-testis transition and displayed defective spermatogenesis at adult stage, which could be rescued by treatment with 11-ketoandrostenedione (11-KA) at certain stages. Specifically, during testis development of cyp11c1-/- males, the expression of insl3, cyp17a1, and amh was significantly decreased, suggesting that 11-KT is essential for the development and function of Leydig cells and Sertoli cells. Further, spermatogenesis-related dmrt1 was subsequently downregulated, leading to insufficient spermatogenesis. The cyp11c1-/- females showed a reduction in egg spawning and a failure of in vitro germinal vesicle breakdown, which could be partially rescued by cortisol treatment. Taken together, our study reveals that zebrafish Cyp11c1 is not required for definite sex differentiation but is essential for juvenile ovary-to-testis transition, Leydig cell development, and spermatogenesis in males through 11-KT, and it is also involved in oocyte maturation and ovulation in females through cortisol.
•Constructed a new CRVI for red vegetation extraction.•Proposed an enhanced semi-automatic PVC algorithm.•The optimal PVIs reflected the phenological differences of vegetation.•The developed ...classification model had spatio-temporal stability and scalability.
Coastal salt marshes, as a globally significantintertidal ecosystem, are highly productive but extremely fragile and unstable. Mapping coastal salt marshes accurately is the basis of assessing global climate change, biological invasion, and coastal erosion. Using Landsat 8 images, this paper integrated the advantages of pixel- and phenology-based algorithms and vegetation indices in vegetation classification. An enhanced phenology-based vegetation index classification (PVC) algorithm is proposed to obtain the spatial distribution and community composition of coastal salt marshes in Bohai Sea of China accurately and quickly. The results showed that (1) the coastal redness vegetation index (CRVI) can be used to extract Suaeda spp. effectively, and the phenology-based vegetation indices (PVIs) dataset can alleviate the spatial variability of phenology in coastal salt marshes; (2) the crucial phenological periods for identifying coastal salt marshes are May, October, and November, and the optimal PVIs are consistent with the phenological characteristics of salt marshes; (3) during the year 2018–2019, the overall accuracy (OA) of the PVC algorithm in Yancheng coast of Jiangsu Province and Bohai Sea coast reached 80.49 % and 90.8 % respectively. A total of 14,763.39 ha of salt marshes were found in the coastal area of Bohai Sea, and Shandong Province had the most abundant types of salt marshes and the largest area; (4) the classification model based on the PVC algorithm is stable and scalable in 2016–2017 and 2020–2021, with the OA of 89.19% and 86.67% respectively. These results demonstrate the value of the PVC algorithm in vegetation classification, and this study can provide a referable semi-automatic vegetation classification method for other coastal areas.
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 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.
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.
•Electropolishing (EP) pretreatment avoided pitting formation during anodization of NiTi alloy.•EP pretreatment extended Ni-Ti-O nanotube length.•EP pretreatment enhanced the corrosion resistance and ...antibacterial property of the nanotubes.
Ni-Ti-O nanotubes (NTs) anodically grown on nearly equiatomic NiTi alloy are promising in biomedical field, but mechanical polishing pretreatment of the substrate usually results in severe pitting. The present work proposes to use electropolishing (EP) as pretreatment of anodization of the NiTi alloy to eliminate the side effect of mechanical polishing. Scanning electron microscopy was used to observe the morphology of the samples. Potentiodynamic polarization test was carried out to evaluate the corrosion behavior. Biological experiments were performed to assay their cytocomaptibility and antibacterial ability. Our results show pitting can be completely avoided after substrate EP pretreatment, yielding a macro smooth surface, while micro ordered nanotubular structure is well preserved. EP pretreatment enhances the corrosion resistance and antibacterial ability of the NiTi alloy when compared with that of mechanically polished sample, and all the samples show no appreciable cytotoxicity, clearly indicating EP is a promising pretreatment for fabricating Ni-Ti-O NTs on the NiTi alloy for biomedical applications.
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.
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•Zn-1 wt%Mg-β-TCP composites with different β-TCP contents were fabricated by vacuum heating-press sintering.•Mg is embedded in the Zn substrate in the form of Zn2Mg and Zn11Mg2, ...while β-TCP particles were evenly distributed in the substrate.•The composites show high yield strength, degradation rate, and osteogenic activity when compared with that of pure zinc.
Repair of bone defects remains a major challenge in the field of orthopedics. Biodegradable zinc (Zn) has been considered as a revolutionary material for bone repair. However, it exhibits relatively poor mechanical strength and cytocompatibility as well as slow degradation rate, hindering its potential application as bone repair material. In the present work, biodegradable Zn-1 wt%Mg-nvol%β-TCP (n = 0, 1, 3, 5, 10) composites are fabricated via vacuum heating-press sintering to address the above concerns. The results show that the addition of magnesium (Mg) and beta-tricalcium phosphate (β-TCP) positively regulate the mechanical properties, degradation properties, and osteogenic activity of the composites. Zn-1 wt%Mg-3 vol%β-TCP possess the highest compressive yield strength of approximately 243.9 MPa compared with about 137.6 MPa of pure Zn. The in vitro corrosion rates of the Zn-1Mg-β-TCP composites are tunable between 0.428 and 0.546 mm/y. The 24-week in vivo experiments prove that the Zn-1Mg-β-TCP composites possess better osteogenic activity than that of pure Zn. In general, the Zn-1Mg-β-TCP composites exhibit suitable mechanical strength and degradation rate, coupled with their great biological activity, which are expected to provide reliable performance for clinical bone repair.
With increased heat control requirements for high-heat-flux products in a narrow heat dissipation space, the ultra-thin micro-heat pipe (MHP) with high heat transfer performance has become an ideal ...heat dissipation component. In this study, the computational fluid dynamics (CFD) method is used to conduct three-dimensional modeling based on the geometric structure characteristics of an ultra-thin MHP. The capillary pressure of the sintered wick is represented by the modified parameter, and a simple and valuable heat and mass transfer model of the ultra-thin MHP is established by fitting the real experimental data through parameter modification. The flow situation of the working medium inside the ultra-thin MHP is analyzed based on the abovementioned parameters. The results show that when the modified parameter is α = 1.5, the temperature equalization requirements of the ultra-thin MHP can be met to the best degree. Moreover, with an increase in heating power, the error value between the surface temperature data of the model and the experimental data of the ultra-thin MHP sample decreases. Under different heating powers, the working medium inside the ultra-thin MHP has the same flow trend. In addition, a 40% increase in temperature difference is found at the junction of the heating section and the adiabatic section, leading to a fluctuation in the temperature gradient on the heat pipe surface. The research results provide a theoretical basis for the model establishment, heat and mass transfer performance investigation, and parameter optimization of ultra-thin MHPs.
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.
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