The Molecular Properties and Roles of Pannier in Harmonia axyridis's Metamorphosis and Melanin Synthesis.

The GATA transcription factor Pannier is identified as the major regulatory gene in color pattern formation in the Asian multi-colored ladybird beetle (Harmonia axyridis). however, the mechanisms of Pannier in regulating melanin synthesis and development in H. axyridis remain elusive. In this study, we identified and characterized Pannier in H. axyridis (HaPnr) and showed it to have two alternative spliced variants named HaPnr-α and HaPnr-ß. Analyses of developmental stage expression patterns revealed that HaPnr, HaPnr-α and HaPnr-ß were constitutively expressed throughout all developmental stages. To examine the role of HaPnr in H. axyridis development, RNA interference was performed in late larvae (the fourth instar) and early pupae (the first day of pupa stage). The transcript levels of HaPnr were effectively suppressed after the injection of double-stranded RNA of HaPnr (dsHaPnr). The fourth instar larvae injected with dsHaPnr reduced the pupation rates to only 61.50%, compared with 88.5% in the dsGFP-injected group. The un-pupated larvae gradually died after 1 week, and visually unaffected pupae emerged into abnormal adults with malformed hind wings and melanin absent from the cuticle. These abnormal adults gradually died 10 days after eclosion. However, when early pupae were injected with dsHaPnr, the normal eclosion rate was achieved at 88.41% on day 6 after the injection. In addition, these successful eclosion adults also showed an absence of melanin in the cuticle, but they could mate normally and have normal fecundity as compared with the control. We further demonstrated that the suppression of HaPnr-α or HaPnr-ß individually did not affect the pupation and eclosion process. The suppression of HaPnr-α expression resulted in elytra melanin decreasing in both the conspicua and the succinea subgroup in H. axyridis. Even though the suppression of HaPnr-ß expression only affected the melanin synthesis in the succinea subgroup, it significantly prolonged the time taken for melanin synthesis to occur in the conspicua subgroup in H. axyridis. These results indicate that HaPnr plays an essential role in insect development, especially during their metamorphosis, and also support our hypothesis that HaPnr could regulate melanin synthesis in H. axyridis under the combined action with its two splicing variants, HaPnr-α and HaPnr-ß.

[Successful treatment of an adult with severe chest trauma under extracorporeal membrane oxygenation: a case report].

Veno-venous extracorporeal membrane oxygenation (VV-ECMO) is a valuable treatment option for chest trauma individuals and some patients required surgery. A 35-year-old female patient with severe chest trauma was admitted to Affiliated Hospital of Zunyi Medical University on February 27, 2020. The patient was hospitalized with chest pain and dyspnea due to fall from a height. Emergency chest CT revealed a right fluid pneumothorax (60% of right lung compression), left hemothorax, little pericardial effusion, and multiple emphysemas in the lower neck, chest, back and mediastinum. Invasive ventilator was difficult to maintain oxygen saturation. After evaluation, the VV-ECMO was established, then, she received a thoracotomy. There was a 1.2 cm trachea rupture observed during operation, and the trachea was repaired. The operation lasted 4 hours with the continuous support of VV-ECMO. When the patient's haemodynamics and oxygenation was stable, ECMO was removed. Sixteen days later, the patient's chest CT showed that, the chest wall subcutaneous emphysema was reduced, and the exudative lesions of both lungs were absorbed, indicating that the patient was treated effectively and reached the discharge standard with no complication. During the treatment of this patient, VV-ECMO was applied rapidly and lasted for a short period, which provided the patient with the opportunity of emergency operation and finally the patient was fully recovered. VV-ECMO can provide support for patients with severe trauma and refractory hypoxemia.

Observation of Switchable Dual-Conductive Channels and Related Nitric Oxide Gas-Sensing Properties in the N-rGO/ZnO Heterogeneous Structure.

Gas sensors based on hybrid materials of graphene oxide/metal oxide semiconductors are an effective way to improve sensor performance. In this paper, we demonstrate a high-performance nitric oxide (NO) gas sensor based on nitrogen-doped reduced graphene oxide/ZnO nanocrystals (N-rGO/ZnO) operating at a low work temperature. ZnO nanocrystals, with an average size of approximately 5 nm, can be uniformly and compactly anchored on the surface of N-rGO using a facile two-step hydrothermal synthesis with an appropriate amount of ammonia as the nitrogen source. The sensor based on the N-rGO/ZnO composite with 0.3 mL of ammonia (N-rGO/ZnO-0.3), in comparison with N-rGO/ZnO with different amounts of ammonia, N-rGO, and rGO/ZnO, exhibited a significantly higher sensitivity (S = Rg/Ra) at the parts per billion (ppb) level for NO gas at 90 °C. The maximum sensitivity at 800 ppb NO was approximately 22, with much faster response and recovery times. In addition, the N-rGO/ZnO-0.3 sensor revealed great stability, a low detection limit of 100 ppb, and an excellent selectivity toward NO versus other gases (NO2, H2, CO, NH3, and CH4), especially at the ppb level. More interestingly, when exposed to oxidizing and reducing gases, unlike conventional semiconductor sensitive materials with resistances that normally change in the opposite direction, only the increase in the resistance is surprisingly and incomprehensibly observed for the N-rGO/ZnO-0.3 sensor. The peculiar sensing behaviors cannot be explained by the conventional theory of the adsorption process, redox reactions on the surfaces, and the well-defined p-n junction between N-rGO and ZnO, originating from the chemical bonding of Zn-C. We propose here for the first time that switchable contribution from dual-conduction paths including the corresponding ZnO channel with the p-n junction and the corresponding N-rGO channel to the sensitivity may exist in the interaction between gases and N-rGO/ZnO-0.3 material. When an oxidizing gas (such as NO) is exposed to the N-rGO/ZnO-0.3 sensor, the contribution from the conductive channel of ZnO nanoparticles and the p-n junction to the sensitivity is dominant. On the contrary, as for a reducing gas (such as H2), the contribution alters to the N-rGO channel as the dominating mode for sensitivity. For gas-sensing behavior of the NGZ-0.1 and NGZ-0.5 sensors, there is only one conduction path from the N-rGO channel for the sensitivity. The model of switchable dual-conduction paths has addressed the mysterious response observed for different gases, which may be utilized to enlighten the understanding of other application problems in nanoscale hybrid materials with a heterogeneous structure.

Molecular and Potential Regulatory Mechanisms of Melanin Synthesis in Harmonia axyridis.

Melanization is a common phenomenon in insects, and melanin synthesis is a conserved physiological process that occurs in epidermal cells. Moreover, a comprehensive understanding of the mechanisms of melanin synthesis influencing insect pigmentation are well-suited for investigating phenotype variation. The Asian multi-colored (Harlequin) ladybird beetle, Harmonia axyridis, exhibits intraspecific polymorphism based on relative levels of melanization. However, the specific characteristics of melanin synthesis in H. axyridis remains elusive. In this study, we performed gene-silencing analysis of the pivotal inverting enzyme, tyrosine hydroxylase (TH), and DOPA decarboxylase (DDC) in the tyrosine metabolism pathway to investigate the molecular and regulatory mechanism of melanin synthesis in H. axyridis. Using RNAi of TH and DDC genes in fourth instar larvae, we demonstrated that dopamine melanin was the primary contributor to the overall body melanization of H. axyridis. Furthermore, our study provides the first conclusive evidence that dopamine serves as a melanin precursor for synthesis in the early pupal stage. According to transcription factor Pannier, which is essential for the formation of melanic color on the elytra in H. axyridis, we further demonstrated that suppression of HaPnr can significantly decrease expression levels of HaTH and HaDDC. These results in their entirety lead to the conclusion that transcription factor Pannier can regulate dopamine melanin synthesis in the dorsal elytral epidermis of H. axyridis.