Comprehensive maturity of nuclear pore complexes regulates zygotic genome activation.

Nuclear pore complexes (NPCs) are channels for nucleocytoplasmic transport of proteins and RNAs. However, it remains unclear whether composition, structure, and permeability of NPCs dynamically change during the cleavage period of vertebrate embryos and affect embryonic development. Here, we report that the comprehensive NPC maturity (CNM) controls the onset of zygotic genome activation (ZGA) during zebrafish early embryogenesis. We show that more nucleoporin proteins are recruited to and assembled into NPCs with development, resulting in progressive increase of NPCs in size and complexity. Maternal transcription factors (TFs) transport into nuclei more efficiently with increasing CNM. Deficiency or dysfunction of Nup133 or Ahctf1/Elys impairs NPC assembly, maternal TFs nuclear transport, and ZGA onset, while nup133 overexpression promotes these processes. Therefore, CNM may act as a molecular timer for ZGA by controlling nuclear transport of maternal TFs that reach nuclear concentration thresholds at a given time to initiate ZGA.

Widespread Enhancer Dememorization and Promoter Priming during Parental-to-Zygotic Transition.

The epigenome plays critical roles in controlling gene expression and development. However, how the parental epigenomes transit to the zygotic epigenome in early development remains elusive. Here we show that parental-to-zygotic transition in zebrafish involves extensive erasure of parental epigenetic memory, starting with methylating gametic enhancers. Surprisingly, this occurs even prior to fertilization for sperm. Both parental enhancers lose histone marks by the 4-cell stage, and zygotic enhancers are not activated until around zygotic genome activation (ZGA). By contrast, many promoters remain hypomethylated and, unexpectedly, acquire histone acetylation before ZGA at as early as the 4-cell stage. They then resolve into either activated or repressed promoters upon ZGA. Maternal depletion of histone acetyltransferases results in aberrant ZGA and early embryonic lethality. Finally, such reprogramming is largely driven by maternal factors, with zygotic products mainly contributing to embryonic enhancer activation. These data reveal widespread enhancer dememorization and promoter priming during parental-to-zygotic transition.

A xenograft model of Kaposiform hemangioendothelioma in nude mice recapitulates Kasabach-Merritt phenomenon.

BACKGROUND: Kasabach-Merritt phenomenon (KMP) is characterized by profound thrombocytopenia and consumptive coagulopathy associated with vascular tumors, such as Kaposiform hemangioendothelioma (KHE). The pathogenesis of KMP remains unclear and its treatment is challenging. In this study, we tried to establish an animal model of KMP, which may facilitate the research on the etiology and new treatment. METHODS: A fresh sample of KHE from a one-month-old female infant with KMP was scissored into pieces and transplanted subcutaneously into the back of the nude mice. Blood routine examination was performed before the transplantation and 2, 4, 8, 12, and 16 weeks after the transplantation. Transplanted tumors were harvested 2, 4, 8, 12, and 16 weeks after the transplantation. H-E staining, immunohistochemistry staining of CD31 and α-SMA, and ultrastructural observation were performed on the plugs. RESULTS: Blood test showed a significant decrease in the number of platelets 2 weeks after transplantation. The number of platelets showed an overall trend of recovery from 2 weeks despite a slight decrease at 12 weeks after transplantation. There was no significant difference in the platelet count at 16 weeks after transplantation compared with the original state. H-E staining showed abundant irregular blood sinuses in the transplanted tumors with plenty of blood cells 2 weeks after the transplantation. 4, 8, and 12 weeks after transplantation, the density of blood sinuses decreased progressively. 16 weeks after transplantation, the plugs involuted into fibrous tissue. Immunohistochemistry staining showed the positive expression of CD31 in the endothelial cells and α-SMA in the perivascular cells. Ultrastructural observation also showed the features of KHE and progressive evolution of the tumors. CONCLUSIONS: We successfully established an experimental model of KMP by the xenograft of KHE in nude mice, which manifested profound thrombocytopenia and typical pathological structure.

Surgical Correction of Orbital Hypertelorism With Absorbable Plate Instead of Frontal and Orbital Bar and Inverted U-Shaped Osteotomy.

OBJECTIVE: The aim of the study is to investigate the effect and feasibility of using absorbable plate instead of frontal and orbital bar and inverted U-shaped osteotomy to correct the widening of orbital distance. METHODS: The surgical effect and feasibility of using absorbable plate instead of frontal and orbital bridge plus inverted U-osteotomy for orbital widening syndrome in seven cases between January 2019 and February 2022 were retrospectively analyzed. First, the surgical procedure for orbital hypertelorism was inverted U-shaped orbital osteotomy, and a frontal bone flap was removed, exposing the superior orbital margin and the orbital circumference, and the orbital bone was directly cut off by inverted U-shaped osteotomy. The widened bone in the middle of the orbit was removed, and a long absorbable plate was used to replace the orbitofrontal bridge. The two sides of the orbit were fixed on the absorbable plate, and the absorbable plate was fixed on the rear skull. The clinical effect of treatment, complications (such as cerebrospinal fluid leakage and infection), safety, and feasibility of surgery were evaluated. RESULTS: Using absorbable plate instead of fronto-orbital bridge achieved the effect of orbitofrontal bridge, without orbital distance widening, cerebrospinal fluid leakage, and intracranial infection. Operating time was reduced. There was no metal fixation, and there was no risk of a second operation. CONCLUSIONS: The effect of replacing the frontal-orbital bridge with an absorbable plate and inverted U-shaped osteotomy is positive, the operation time is short, and the orbital distance is clearly improved. This approach can replace the traditional orbital-distance operation, and the incidence of postoperative cerebrospinal fluid leakage and infection is low. Long-term follow-up results are stable.

Impact of Anterior and Posterior Vault Distraction Osteogenesis (A-PVDO) and 3D-Printed Positioning/Shaping Templates in Apert Syndrome: A Case Series Study.

OBJECTIVE: This study seeks to examine the impact of anterior and posterior vault distraction osteogenesis (A-PVDO) in conjunction with 3D-printed positioning and shaping templates for the management of Apert syndrome. METHODS: From January 2018 to February 2022, a retrospective analysis was conducted on 6 cases of Apert syndrome employing fronto-orbital 3D-printed positioning and molding templates. The cranium underwent surgical modification in accordance with the template's configuration and was affixed with absorbable plates. Subsequently, distraction devices were applied, encompassing both anterior and posterior craniotomies. The evaluation encompassed clinical outcomes, complications (including cerebrospinal fluid leakage and infection), safety, and the feasibility of the distraction osteogenesis procedure. RESULTS: Six patients diagnosed with Apert syndrome underwent treatment involving the integration of fronto-orbital 3D-printed positioning and shaping templates in conjunction with anterior and posterior cranial distraction osteoplasty. Follow-up durations ranged from 18 to 32 months (average: 22 mo). No instances of fronto-orbital retraction, cerebrospinal fluid leakage, or intracranial infection were noted during the follow-up period. The sole reported complication entailed an infection at the extension rod site in 1 case. All patients conveyed satisfaction with the treatment outcomes. CONCLUSIONS: The application of 3D-printed positioning and shaping templates in tandem with anterior and posterior cranial distraction osteogenesis demonstrates efficacy in addressing Apert syndrome. Notably, significant enhancements in head shape and orbit were observed, and the incidence of postoperative complications such as cerebrospinal fluid leakage and infection remained minimal. Moreover, long-term follow-up affirmed stability.

Mini-III RNase-based dual-color system for in vivo mRNA tracking.

Mini-III RNase (mR3), a member of RNase III endonuclease family, can bind to and cleave double-stranded RNAs (dsRNAs). Inactive mR3 protein without the α5ß-α6 loop loses the dsRNA cleavage activity, but retains dsRNA binding activity. Here, we establish an inactive mR3-based non-engineered mR3/dsRNA system for RNA tracking in zebrafish embryos. In vitro binding experiments show that inactive Staphylococcus epidermidis mR3 (dSmR3) protein possesses the highest binding affinity with dsRNAs among mR3s from other related species, and its binding property is retained in zebrafish embryos. Combined with a fluorescein-labeled antisense RNA probe recognizing the target mRNAs, dSmR3 tagged with a nuclear localization sequence and a fluorescent protein could allow visualization of the dynamics of endogenous target mRNAs. The dSmR3/antisense probe dual-color system provides a new approach for tracking non-engineered RNAs in real-time, which will help understand how endogenous RNAs dynamically move during embryonic development.

PEEP application during mechanical ventilation contributes to fibrosis in the diaphragm.

BACKGROUND: Positive end-expiratory airway pressure (PEEP) is a potent component of management for patients receiving mechanical ventilation (MV). However, PEEP may cause the development of diaphragm remodeling, making it difficult for patients to be weaned from MV. The current study aimed to explore the role of PEEP in VIDD. METHODS: Eighteen adult male New Zealand rabbits were divided into three groups at random: nonventilated animals (the CON group), animals with volume-assist/control mode without/ with PEEP 8 cmH2O (the MV group/ the MV + PEEP group) for 48 h with mechanical ventilation. Ventilator parameters and diaphragm were collected during the experiment for further analysis. RESULTS: There was no difference among the three groups in arterial blood gas and the diaphragmatic excursion during the experiment. The tidal volume, respiratory rate and minute ventilation were similar in MV + PEEP group and MV group. Airway peak pressure in MV + PEEP group was significantly higher than that in MV group (p < 0.001), and mechanical power was significantly higher (p < 0.001). RNA-seq showed that genes associated with fibrosis were enriched in the MV + PEEP group. This results were further confirmed on mRNA expression. As shown by Masson's trichrome staining, there was more collagen fiber in the MV + PEEP group than that in the MV group (p = 0.001). Sirius red staining showed more positive staining of total collagen fibers and type I/III fibers in the MV + PEEP group (p = 0.001; p = 0.001). The western blot results also showed upregulation of collagen types 1A1, III, 6A1 and 6A2 in the MV + PEEP group compared to the MV group (p < 0.001, all). Moreover, the positive immunofluorescence of COL III in the MV + PEEP group was more intense (p = 0.003). Furthermore, the expression of TGF-ß1, one of the most potent fibrogenic factors, was upregulated at both the mRNA and protein levels in the MV + PEEP group (mRNA: p = 0.03; protein: p = 0.04). CONCLUSIONS: We demonstrated that PEEP application for 48 h in mechanically ventilated rabbits will cause collagen deposition and fibrosis in the diaphragm. Moreover, activation of the TGF-ß1 signaling pathway and myofibroblast differentiation may be the potential mechanism of this diaphragmatic fibrosis. These findings might provide novel therapeutic targets for PEEP application-induced diaphragm dysfunction.

Cellular senescence contributes to mechanical ventilation-induced diaphragm dysfunction by upregulating p53 signalling pathways.

BACKGROUND: Mechanical ventilation can cause acute atrophy and injury in the diaphragm, which are related to adverse clinical results. However, the underlying mechanisms of ventilation-induced diaphragm dysfunction (VIDD) have not been well elucidated. The current study aimed to explore the role of cellular senescence in VIDD. METHODS: A total of twelve New Zealand rabbits were randomly divided into 2 groups: (1) spontaneously breathing anaesthetized animals (the CON group) and (2) mechanically ventilated animals (for 48 h) in V-ACV mode (the MV group). Respiratory parameters were collected during ventilation. Diaphragm were collected for further analyses. RESULTS: Compared to those in the CON group, the percentage and density of sarcomere disruption in the MV group were much higher (p < 0.001, both). The mRNA expression of MAFbx and MuRF1 was upregulated in the MV group (p = 0.003 and p = 0.006, respectively). Compared to that in the CON group, the expression of MAFbx and MuRF1 detected by western blotting was also upregulated (p = 0.02 and p = 0.03, respectively). Moreover, RNA-seq showed that genes associated with senescence were remarkably enriched in the MV group. The mRNA expression of related genes was further verified by q-PCR (Pai1: p = 0.009; MMP9: p = 0.008). Transverse cross-sections of diaphragm myofibrils in the MV group showed more intensive positive staining of SA-ßGal than those in the CON group. p53-p21 axis signalling was elevated in the MV group. The mRNA expression of p53 and p21 was significantly upregulated (p = 0.02 and p = 0.05, respectively). The western blot results also showed upregulation of p53 and p21 protein expression (p = 0.03 and p = 0.05, respectively). Moreover, the p21-positive staining in immunofluorescence and immunohistochemistry in the MV group was much more intense than that in the CON group (p < 0.001, both). CONCLUSIONS: In a rabbit model, we demonstrated that mechanical ventilation in A/C mode for 48 h can still significantly induce ultrastructural damage and atrophy of the diaphragm. Moreover, p53-dependent senescence might play a role in mechanical ventilation-induced dysfunction. These findings might provide novel therapeutic targets for VIDD.

Posterior Cranial Retraction Combined With Bilateral Parietal Distraction for Children With Nonsyndromic Craniosynostosis.

BACKGROUND: The nonsyndromic craniosynostosis is the most common of craniosynostoses in childhood. There are many treatments. We aim to treat 12 cases of nonsyndromic craniosynostosis via posterior cranial vault distraction osteogenesis combined with bilateral parietal distraction. METHODS: Data of a total of 12 patients (7 boys and 5 girls) with nonsyndromic sagittal synostosis who underwent distraction osteogenesis between January 2015 and August 2020 were retrospectively analyzed. Bilateral parietal bone flaps and posterior occipital flaps were designed and cut. Then, distraction device was placed, which was distracted at 5 days after surgery (twice per day, 0.4-0.6 mm/d, and lasting for 10-15 days). After 6 months of fixation, the secondary surgery was performed to remove the device. RESULTS: The scaphocephaly was corrected, and the appearance was satisfactory. Postoperative follow-up time was 6 to 14 months, with an average of 10 months, and the mean CI was 63.2 and 78.25 before and after surgery, respectively; the mean anterior-posterior skull diameter was shortened (12.63 ± 3.47) mm, the transverse diameter of both temporal regions was lengthened (15.4 ± 4.18) mm, and the scaphocephalic deformity was significantly improved. There was no detachment or rupture of the extender postoperatively. No severe complications, such as radiation necrosis or intracranial infection, were observed. CONCLUSION: Posterior cranial retraction combined with bilateral parietal distraction in children with nonsyndromic craniosynostosis, in which the proposed technique did not exhibit severe complications, and it is worthy of further promotion and application in clinical practice.

Occurrence of Rhabdomyosarcoma After Surgery Combined with oral Sirolimus for Mixed Vascular Malformation of the Tongue.

Vascular malformation is the general term of a kind of lesions originated from lymphatic vessels and vascular tissues, which contains a variety of components called mixed vascular malformation. Rhabdomyosarcoma (RMS) is a kind of soft tissue sarcoma, originating from striated muscle cells or mesenchymal cells. RMS and vascular malformation mostly occur in children, and common in the head and neck, but their simultaneous occurrence is rare. A 9-year-old boy who was hospitalized for a second attack of combined vascular malformation: hemolymphangioma. The child experienced severe upper airway obstruction and tongue bleeding. Postoperative pathology demonstrated hemolymphangioma combined with RMS. Subsequently, he was transferred to the oncology department for chemotherapy and lately died of RMS with lung metastasis. The secondary RMS may be related to the usage of sirolimus. Because of its uncertain border, vascular malformation in the oral and maxillofacial region is difficult to completely remove by surgical resection, and local recurrence could be often observed. Due to its rapid progress and continuous bleeding, the possibility of malignant tumor should be considered and multidisciplinary comprehensive treatment should be actively taken. Besides, family history of related malignant tumors and immune function should be investigated in detail before choosing the application of oral sirolimus.

Closure of Giant Dorsal Lumbosacral Myelomeningocele in Children Using Double Expanded Flaps: A Case Report and Literature Review.

INTRODUCTION: Myelomeningocele (MMC) is the most common neural tube defect that can occur due to neural tube's failure to fuse properly during embryonic life. To prevent this, expanded flaps can be used for closure of large MMCs. PRESENTATION OF CASE: A 4-year and 6-month girl was diagnosed with multiple congenital anomalies including hydrocephalus, dorsal lumbosacral MMC, and congenital tethered cord syndrome. Preoperative evaluation showed no lower limb movements and the size of the sacrococcygeal region was about 10 cm × 8 cm × 15 cm mass, prominent thoracic kyphosis, and no obvious urogenital or limb anomalies. The large dorsal lumbosacral MMC was treated with a double expanded flap to reconstruct, the soft tissue defect following the neurosurgical reconstruction. DISCUSSION: The expanded flap was deemed as viable as all wounds were healed without any complications, such as dehiscence, leakage of cerebrospinal fluid, or infection. The technique described in the case report offers an effective method of closure. CONCLUSION: This flap can be an effective method for reconstruction of large dorsal lumbosacral MMC defects that might improve outcomes and minimize complications. It also ensures minimal wound tension and breakdown.

Application of Computer-Assisted Preoperative Planning in Treating Congenital Bilateral Zygomatico-Maxillo-Mandibular Fusion: A Case Report and Literature Review.

Congenital fusion of the jaws (syngnathia) is a rare facial malformation with an unknown etiology. This disease may vary in severity with adhesion of soft tissue and bony fusion. It can be anterior fusion, unilateral or bilateral fusion, and complete fusion. The main problem of these patients is the difficulty of airway maintenance and feeding, and the most common postoperative complication is the relapse of bony fusion. Here, we report a young male patient with bony syngnathia, involving bilateral fusion of the ascending ramus and body of the mandible with the maxillary complex. We performed bone isolation by computer-assisted preoperative planning and used an insertional temporalis flap to fix the wound surface to prevent refusion of bone.

Abnormal ADAMTS2 and VSIG4 in Serum of HF Patients and their Relationship with CRP, UA, and HCY.

BACKGROUND: Abnormal A Disintegrin and Metalloproteinase with Thrombospondin Motifs 2 (ADAMTS2) and V-set and immunoglobulin domain-containing 4 (VSIG4) were explored in serum of heart failure (HF) patients and its association with C-reactive protein (CRP), uric acid (UA), and homocysteine (HCY) indexes was manifested. METHODS: ADAMTS2 and VSIG4 expression in serum of HF patients was analyzed. Pearson's correlation coefficient analysis was employed to evaluate the correlation between the indexes. Receiver operating characteristic (ROC) curves to assess the recognition ability of ADAMTS2, VSIG4, and brain natriuretic peptide (BNP) for HF. Kaplan-Meier survival curve and multivariate Cox regression were applied to analyze the prognostic value of ADAMTS2 and VSIG4. RESULTS: ADAMTS2 and VSIG4 were upregulated in serum of HF patients. ROC curve affirmed that ADAMTS2 and VSIG4 in serum manifested diagnostic value for HF, and the combined diagnosis accuracy of ADAMTS2, VSIG4, and BNP was greatly improved. Kaplan-Meier and multivariate Cox regression analysis suggested that reduced ADAMTS2 and VSIG4 could forecast the overall survival of HF patients. CONCLUSIONS: This study assures that ADAMTS2 and VSIG4 are strengthening in HF patients, which makes them new non-invasive biomarkers for the diagnosis and prognosis of HF.

Design, fabrication, and testing of an all-metal ultra-compact telescope.

The design, fabrication, and testing of an all-metal four-mirror telescope for high-resolution remote sensing is presented in this paper. The system works in the visible (VIS) band and is designed with a focal length of 1406 mm, an aperture of 200 mm, and a full field of view (FOV) of 1.32°. The mechanical structure is designed to realize the snap-together alignment. The primary mirror (M1) and tertiary mirror (M3) are designed as a co-substrate element to simplify the fabrication and alignment. The telescope's weight is 3.5 kg, and the volume is just φ230×220mm3. Metallic mirrors are fabricated with single-point diamond turning, and post-polishing is used to correct the mirror's surface form deviation and remove turning tool marks effectively. After polishing, the RMS value of the mirror surface form deviation of the final mirror can reach 0.02λ at λ=632.8nm, and the surface roughness Ra value is about 1.83 nm. Benefiting from the all-metal mechanical design, the alignment process of the telescope is fast and accurate. The interferometric wavefront, modulation transfer function, and focal length of the telescope are measured, and the results demonstrated that it achieves the near-diffraction-limited imaging performance.

Management of Macrocystic Lymphatic Malformation in the Cervicofacial Region: Ultrasound-Guided Iodine Tincture Cauterization Combined With Intralesional Negative Pressure.

PURPOSE: The purpose of our study was to evaluate the efficacy and safety of ultrasound-guided iodine tincture cauterization combined with postoperative intralesional negative pressure in the management of cervicofacial cystic lymphatic malformation (cLM). METHOD: From January 2019 to July 2021, indocyanine green lymphography was performed preoperatively to confirm the lymph inflow, and this treatment was administered in 71 patients with cervicofacial cLM in our center. All cases were evaluated by curative effects, treatment frequency, and adverse events. The duration of posttreatment follow-up was from 12 to 14 months. RESULTS: Indocyanine green lymphography indicated at least one lymphatic inflow in each cLM lesion. Excellent resolution was observed in 87.3% of cases, and good improvement of the treated cLM occurred in 9.9% of cases, and 2 cases with fair outcomes required subsequent treatment. It is noteworthy that no case was treated more than 3 times. Some minor adverse effects, including localized itch and scar, were managed by symptomatic treatment. CONCLUSIONS: Because of satisfactory outcomes and low treatment frequency, ultrasound-guided iodine tincture cauterization combined with intralesional negative pressure represents an efficacious, safe, and feasible method for the management of macro-cLM in the cervicofacial region.

Treatment of Syndromic Craniosynostosis by Anterior and Posterior Vault Distraction Osteogenesis (A-PVDO).

OBJECTIVE: To explore the feasibility and therapeutic effect of anterior and posterior vault distraction osteogenesis (A-PVDO) in the treatment of infantile syndromic craniosynostosis. METHODS: Between January 2017 and December 2019, 7 children with syndromic craniosynostosis underwent osteotomy with Piezo-surgery at our hospital. The first step was to harvest the frontal bone flap and the orbitofrontal bone flap. The second step was to separate the scalp and expose the posterior occipital. Osteotomy was performed on the occipital tubercle. Thereafter, 2 distractors were horizontally installed on the upper edge of the anterior cranial orbit, 2 distractors of 3 cm were installed on the posterior cranial bone. Meanwhile, lambdoidal sutures were fixed by titanium plates. Bone distraction was initiated on postoperative day 5 at the rate of 0.4 to 0.6 mm/day, twice per-day, for a total of 10 to 15 days. After 6 months, the distractors and the titanium plates were removed by secondary surgery. RESULTS: The intracranial volume and posterior cranial morphology were recorded during the follow-up of 6 to 14 months (average = 12 months). The posterior craniums of 7 cases with lambdoidal sutures fixation were completely extended. The anterior cranial morphology was normal. All the cranial deformities were significantly improved. There were no severe complications, such as death, cranial necrosis, and intracranial infection. CONCLUSIONS: A-PVDO is an ideal method for the treatment of severe syndromic craniosynostosis, which can achieve more natural appearance than anterior vault distraction osteogenesis or posterior vault distraction osteogenesis. Moreover, A-PVDO causes no severe complications and is suitable for the treatment of severe syndromic craniosynostosis.

Intermittent Administration Regimen of Sirolimus for Refractory Cervicofacial Lymphatic Malformation.

BACKGROUND: The cervicofacial lymphatic malformations (LMs) often have poor outcomes due to their microcystic component and diffuse infiltration. Mostly, traditional treatments are inadequate for these refractory cases. Recent researches have shown that sirolimus is effective in the treatment of complicated LMs, however, there is still no standard strategy. OBJECTIVE: To evaluate the efficacy and safety of intermittent oral sirolimus in treating refractory cervicofacial LMs as a second-line treatment. METHODS: Fifteen pediatric patients of refractory cervicofacial LMs were retrospectively analyzed in this study. All the cases had received traditional therapy before, but could not completely control the symptoms and eliminate lesions. As a remedy, sirolimus was then proceeded with an intermittent administration regimen, that is 3 continuous months as a course and started the next course after 1 month interval. The clinical characteristics, imaging data of patients, the changes in the signs and symptoms observed, and associated adverse effects were collected and analyzed. RESULTS: The patients initiated sirolimus therapy at the average age of 2.3 years (range 28 days-8 years 9 months). At the end point of the study, 2 patients remained on sirolimus in continuous courses of treatment. Of 13 patients who withdrawn therapy, 4 had restarted due to recurrence of symptoms and re-expansion of LMs. All patients demonstrated reduction in residual LMs and complete disappearance of symptoms during treatment, and 2 patients with complete resolution on imaging. Toxicity was tolerant in this series. There was no patient develop opportunistic or systemic bacterial infection. CONCLUSIONS: Sirolimus is commended as a second-line treatment to treat intractable cervicofacial LMs after failure of traditional therapy. The intermittent administration regimen is efficacious to completely control symptoms and partially reduce residual lesions with good tolerance and limited side effects.

Maternal Ybx1 safeguards zebrafish oocyte maturation and maternal-to-zygotic transition by repressing global translation.

Maternal mRNAs and proteins dictate early embryonic development before zygotic genome activation. In the absence of transcription, elaborate control of maternal mRNA translation is of particular importance for oocyte maturation and early embryogenesis. By analyzing zebrafish ybx1 mutants with a null allele, we demonstrate an essential role of maternal ybx1 in repressing global translation in oocytes and embryos. Loss of maternal Ybx1 leads to impaired oocyte maturation and egg activation. Maternal ybx1 (Mybx1) mutant embryos fail to undergo normal cleavage and the maternal-to-zygotic transition (MZT). Morpholino knockdown of ybx1 also results in MZT loss and epiboly failure, suggesting the postfertilization requirement of Ybx1. In addition, elevated global translation level and the unfolded protein response were found in Ybx1-depleted embryos. Supplementing translational repression by eIF4E inhibition markedly rescues the Mybx1 phenotype. Mechanistically, Ybx1 in embryos may associate with processing body components and repress translation when tethered to target mRNAs. Collectively, our results identify maternal Ybx1 as a global translational repressor required for oocyte maturation and early embryogenesis.

Design and manufacture of miniaturized immersed imaging spectrometer for remote sensing.

A miniaturized immersed imaging spectrometer possessing long slit and large relative aperture is proposed. It is integrated monolithically with three concentric optical components. Through the chief ray tracing, we analyzed its astigmatism characteristic and then deduced the anastigmatic condition for long slit. Meanwhile, it is athermal by matching the suitable lens materials to compensate thermal defocus. Based on the anastigmatic and athermal conditions, we have designed a miniaturized VNIR immersed imaging spectrometer and developed the prototype. Its slit is 48 mm long and it is optically fast with an F-number of 2.5. The new form shows about 12 times smaller in volume than the classic Offner-Chrisp imaging spectrometer and weighs only 2 kg, and has excellent thermal adaptability while temperature changes between -40 °C and 60 °C. Meanwhile, fabrication of core elements and gluing process of the immersed imaging spectrometer are presented. Test results of the prototype show superior performance with high imaging quality and small smile and keystone distortions. Such miniaturized immersed imaging spectrometer will greatly improve the performance and reduce the costs of wide swath hyperspectral remote sensing, and is desirable for usage on small plane or satellite platforms.

Long-slit polarization-insensitive imaging spectrometer for wide-swath hyperspectral remote sensing from a geostationary orbit.

To improve the swath width and quantitative accuracy of hyperspectral payloads on a geostationary orbit, a long-slit polarization-insensitive imaging spectrometer is designed and demonstrated in this paper. For the wide swath, several long-slit spectrometers with the same specification have been designed and compared. The result shows that the Wynne-Offner spectrometer has advantages in increasing slit length and reducing volume, and it is suitable for being spliced for ultra-wide swath. To solve the problem of inaccurate radiation measuring caused by the polarization of imaging spectrometers, the requirement for linear polarization sensitivity (LPS) is theoretically analyzed and assessed. As diffraction grating is the main polarization-sensitive element in an imaging spectrometer, we propose to increase the apical angle of the grating groove to reduce its LPS and compensate its residual polarization by specially polarized optical films coated on lens surfaces, thus the polarization-insensitive system is achieved. At last, a VNIR spectrometer with superior spatial and spectral performance is developed, and its slit is 61.44 mm long. The maximum LPS of this system is reduced from 10.0% to 2.3% (test 2.5%) after the depolarization design, which greatly reduces the uncertainty of the measuring radiation caused by polarization. The developed imaging spectrometer can play a role in quantitative hyperspectral remote sensing, especially in wide-swath applications on geostationary orbit.