An Ascovirus Utilizes Different Types of Host Larval Regulated Cell Death Mechanisms To Produce and Release Vesicles.

Ascoviruses are insect-specific viruses that are thought to utilize the cellular apoptotic processes of host larvae to produce numerous virion-containing vesicles. In this study, we monitored the in vivo infection processes of Heliothis virescens ascovirus 3h (HvAV-3h) to illustrate the regulated cell death (RCD) of host cells. Transmission electron microscopic observations did not reveal any morphological markers of apoptosis in the fat bodies or hemocytes of HvAV-3h-infected Helicoverpa armigera or Spodoptera exigua larvae. However, several hemocytes showed the morphological criteria for necrosis and/or pyroptosis. Further in vitro biochemical tests were performed to confirm the RCD type of host cells after infection with HvAV-3h. Different morphological characteristics were found between the early (prior to 24 hours post-infection, [hpi]) and later (48 to 120 hpi) stages in both HvAV-3h infected larval fat bodies and hemocytes. In the early stages, the virions could only be found in several adipohemocytes, and the fat bodies were cleaving their contained lipid inclusions into small lipid dots. In the later stage, both fat bodies and hemocytes were filled with numerous virions. According to the morphological characteristics of HvAV-3h infected larval fat bodies or hemocytes, the pathogenic characteristics and infection patterns of HvAV-3h in the host larvae were described, and the systematic pathogenic mode of ascovirus infection was refined in this study. This study details the complete infection process of ascoviruses, which provides insights into the relationship between a pathogenesis of an insect virus and the RCD of different host tissues at different stages of infection. IMPORTANCE Viruses and other pathogens can interrupt host cellular apoptosis to gain benefits, such as sufficient resources and a stable environment that enables them to complete their replication and assembly. It is unusual for viruses to code proteins with homology to caspases, which are commonly recognized as apoptosis regulators. Ascoviruses are insect viruses with special cytopathology, and they have been hypothesized to induce apoptosis in their host larvae via coding a caspase-like protein. This enables them to utilize the process of cellular apoptosis to facilitate vesicle formation and replication. However, our previous studies revealed different trends. The fat bodies and hemocytes of Heliothis virescens ascovirus 3h (HvAV-3h)-infected larvae did not show any morphological markers of apoptosis but did display necrosis and/or pyroptosis morphological characteristics. The pathogenic characteristics and infection patterns of HvAV-3h in the host larvae were described, which can help us understand the relationship between the pathogenesis of an insect virus and host RCD.

Semiconductor Optical Amplifiers with Wide Gain Bandwidth and Enhanced Polarization Insensitivity Based on Tensile-Strained Quantum Wells.

The paper presents a wide-bandwidth, low-polarization semiconductor optical amplifier (SOA) based on strained quantum wells. By enhancing the material gain of quantum wells for TM modes, we have extended the gain bandwidth of the SOA while reducing its polarization sensitivity. Through a combination of tilted waveguide design and cavity surface optical thin film design, we have effectively reduced the cavity surface reflectance of the SOA, thus decreasing device transmission losses and noise figure. At a wavelength of 1550 nm and a drive current of 1.4 A, the output power can reach 188 mW, with a small signal gain of 36.4 dB and a 3 dB gain bandwidth of 128 nm. The linewidth broadening is only 1.032 times. The polarization-dependent gain of the SOA is below 1.4 dB, and the noise figure is below 5.5 dB. The device employs only I-line lithography technology, offering simple fabrication processes and low costs yet delivering outstanding and stable performance. The designed SOA achieves wide gain bandwidth, high gain, low polarization sensitivity, low linewidth broadening, and low noise, promising significant applications in the wide-bandwidth optical communication field across the S + C + L bands.

Enhanced virulence of genetically engineered Autographa californica nucleopolyhedrovirus owing to accelerated viral DNA replication aided by inserted ascovirus genes.

Genetic engineering technology is an ideal method to improve insecticidal efficiency by combining the advantages of different pathogenic microorganisms. Thus, six ascovirus genes were introduced into the genomic DNA of Autographa californica nucleopolyhedrovirus (AcMNPV) to possibly transfer the intrinsically valuable insecticidal properties from ascovirus to baculovirus. The viral budded virus (BV) production and viral DNA replication ability of AcMNPV-111 and AcMNPV-165 were significantly stronger than that of AcMNPV-Egfp (used as the wild-type virus in this study), whereas AcMNPV-33 had reduced ones. AcMNPV-111 and AcMNPV-165 also exhibited excellent insecticidal efficiency in the in vivo bioassays: AcMNPV-111 showed a 24.1% decrease in the LT50 value and AcMNPV-165 exhibited a 56.3% decrease in the LD50 value compared with AcMNPV-Egfp against the 3rd instar of Spodoptera exigua larvae, respectively. Furthermore, the size of the occlusion bodies (OBs) of AcMNPV-33, AcMNPV-111, and AcMNPV-165 were significantly increased compared to that of AcMNPV-Egfp. AcMNPV-111 and AcMNPV-165 had stable virulence against the 2nd to 4th instars tested larvae and higher OB yield than AcMNPV-Egfp in the 3rd and 4th instar larvae. Correlation and regression analyses indicated that it is better to use 5 OBs/larva virus to infect the 2nd instar larvae to produce AcMNPV-111 and 50 OBs/larva virus to infect the 3rd instar larvae to produce AcMNPV-165. The results of this study obtained recombinant viruses with enhanced virulence and exhibited a diversity of ascovirus gene function based on the baculovirus platform, which provided a novel strategy for the improvement of baculovirus as a biological insecticide.

A Review of High-Power Semiconductor Optical Amplifiers in the 1550 nm Band.

The 1550 nm band semiconductor optical amplifier (SOA) has great potential for applications such as optical communication. Its wide-gain bandwidth is helpful in expanding the bandwidth resources of optical communication, thereby increasing total capacity transmitted over the fiber. Its relatively low cost and ease of integration also make it a high-performance amplifier of choice for LiDAR applications. In recent years, with the rapid development of quantum-well (QW) material systems, SOAs have gradually overcome the shortcomings of polarization sensitivity and high noise. The research on quantum-dot (QD) materials has further improved the noise characteristics and transmission loss of SOAs. The design of special waveguide structures-such as plate-coupled optical waveguide amplifiers and tapered amplifiers-has also increased the saturation output power of SOAs. The maximum gain of the SOA has been reported to be more than 21 dB. The maximum saturation output power has been reported to be more than 34.7 dBm. The maximum 3 dB gain bandwidth has been reported to be more than 120 nm, the lowest noise figure has been reported to be less than 4 dB, and the lowest polarization-dependent gain has been reported to be 0.1 dB. This study focuses on the improvement and enhancement of the main performance parameters of high-power SOAs in the 1550 nm band and introduces the performance parameters, the research progress of high-power SOAs in the 1550 nm band, and the development and application status of SOAs. Finally, the development trends and prospects of high-power SOAs in the 1550 nm band are summarized.

Heliothis virescens ascovirus 3h blocks the cell cycle of Spodoptera exigua fat body cells at G2 /M phase by downregulating cyclin B1 and cyclin-dependent kinase 1.

Ascoviruses are double-stranded DNA viruses that are pathogenic to noctuid larvae. In vitro infection causes the cells to fail to replicate and proliferate normally. However, the molecular mechanisms are unclear. In this study, the transmission electron microscopy data of infected-Spodoptera exigua (Hübner) fat body cells (SeFB, IOZCAS-SpexII-A cells) showed that virions were internalized in phagocytic vesicles, but not in the nucleus. FACS of cell-cycle progression was performed in SeFB cells infected with Heliothis virescens ascovirus 3h (HvAV-3h). The cell cycle phase distributions of the SeFB cells were G1 = 29.52 ± 1.10%, S = 30.33 ± 1.19%, and G2 /M = 40.06 ± 0.75%. The cell culture doubling time was approximately 24 h. The G1 , S, and G2 /M phases were each approximately 8 h. The unsynchronized or synchronized cells were arrested at G2 /M phase after infection with HvAV-3h. Our data also showed that cells with more than 4N DNA content appeared in the HvAV-3h-treated group. While the mRNA levels of cyclin B1 , cyclin H, and cyclin-dependent kinase 1 (CDK1) were downregulated after HvAV-3h infection, the mRNA expression levels of cyclin A, cyclin D, and cyclin B2 were not significantly changed. Western blotting results showed that the expression of cyclin B1 and CDK1 in infected SeFB cells within 24 h postinfection (hpi), and HvAV-3h infection inhibited the expression of cyclin B1 and CDK1 at 12-24 hpi. Overall, these data implied that HvAV-3h infection leads to an accumulation of cells in the G2 /M phases by downregulating the expression of cyclin B1 and CDK1.

Comparisons of pathogenic course of two Heliothis virescens ascovirus isolates (HvAV-3i and HvAV-3j) in four noctuid (Lepidoptera) pest species.

Ascoviruses are fatal double-stranded DNA viruses with a special pathogenesis in which cells are converted into vesicles with virions. Several closely related ascovirus isolates that shared more than 90% genomic DNA identity showed different pathogenic courses in previous studies. To investigate the pathogenic differences between the related ascovirus isolates, Heliothis virescens ascovirus 3i (HvAV-3i) and Heliothis virescens ascovirus 3j (HvAV-3j) were used to inoculate four noctuid pest species (Helicoverpa armigera, Mythimna separata, Spodoptera frugiperda, and Spodoptera litura), and the pathogenic indexes were recorded. The mortality of HvAV-3i infected H. armigera and S. frugiperda was approximately 60%, while the other HvAV-infected larvae had mortality rates above 90%. The maximum lethal dilution ratios of HvAV-3i in H. armigera, M. separata, S. frugiperda, and S. litura were 1.90 × 107, 1.90 × 103, 1.90 × 108, and 1.90 × 104 viral genome DNA copies/mL, respectively, while the ratios of HvAV-3j were 8.22 × 106, 8.22 × 102, 8.22 × 105, and 8.22 × 103 viral genome DNA copies/mL, respectively. Extended larval survival time was found in the HvAV-infected larvae; median survival time of the HvAV-infected larvae ranged from 13 to 19 days. An additional larval instar was found in HvAV-infected M. separata, S. frugiperda, and S. litura. Larval growth and food intake were significantly inhibited from 2 days post-infection (dpi) in the tested H. armigera, S. frugiperda, and S. litura after infection with HvAV-3i or HvAV-3j. The detoxification enzyme activity of host larvae was influenced after infection with HvAVs, and two different regulation patterns were detected, one in infected H. armigera and M. separata and the other in S. frugiperda and S. litura. The results obtained in this study provide insights into the pathogenic characteristics of ascoviruses.

The Role of Lanthanum Stearate on Strain-Induced Crystallization and the Mechanical Properties of Whole Field Latex Rubber.

Natural rubber (NR) is extensively utilized in numerous industries, such as aerospace, military, and transportation, because of its exceptional elasticity and all-around mechanical qualities. However, commercial NR made using various techniques typically has distinct mechanical characteristics. For instance, whole field latex rubber (SCR-WF) cured with accelerator 2-Mercaptobenzothiazole exhibits poor mechanical properties. This work attempts to enhance the mechanical property of SCR-WF via the addition of lanthanum stearate (LaSt). The influence of LaSt on strain-induced crystallization (SIC) and the mechanical properties of SCR-WF were investigated. The results of crosslinking density measured by the equilibrium swelling method demonstrate that the presence of LaSt significantly increases the crosslinking density of SCR-WF with lower loading of LaSt. The results of the mechanical properties show that the introduction of LaSt can enhance the tensile strength and fracture toughness of SCR-WF. To reveal the mechanism of LaSt improving the mechanical properties of SCR-WF, synchrotron radiation wide-angle X-ray diffraction (WAXD) experiments were used to investigate the SIC behaviors of SCR-WF. We found that the LaSt leads to higher crystallinity of SIC for the strain higher than 3.5. The tube model indicates the contribution of LaSt in both crosslinking and topological constraints. This work may provide an instruction for developing SCR-WF with superior mechanical properties.

Feeding Spodoptera exigua larvae with gut-derived Escherichia sp. increases larval juvenile hormone levels inhibiting cannibalism.

Feed quality influences insect cannibalistic behavior and gut microbial communities. In the present study, Spodoptera exigua larvae were fed six different artificial diets, and one of these diets (Diet 3) delayed larval cannibalistic behavior and reduced the cannibalism ratio after ingestion. Diet 3-fed larvae had the highest gut bacterial load (1.396 ± 0.556 × 1014 bacteria/mg gut), whereas Diet 2-fed larvae had the lowest gut bacterial load (3.076 ± 1.368 × 1012 bacteria/mg gut). The gut bacterial composition and diversity of different diet-fed S. exigua larvae varied according to the 16S rRNA gene sequence analysis. Enterobacteriaceae was specific to the Diet 3-fed larval gut. Fifteen culturable bacterial isolates were obtained from the midgut of Diet 3-fed larvae. Of these, ten belonged to Escherichia sp. After administration with Diet 1- or 2-fed S. exigua larvae, two bacterial isolates (SePC-12 and -37) delayed cannibalistic behavior in both tested larval groups. Diet 2-fed larvae had the lowest Juvenile hormone (JH) concentration and were more aggressive against intraspecific predation. However, SePC-12 loading increased the JH hormone levels in Diet 2-fed larvae and inhibited their cannibalism. Bacteria in the larval midgut are involved in the stabilization of JH levels, thereby regulating host larval cannibalistic behavior.

Flexible changes to the Heliothis virescens ascovirus 3h (HvAV-3h) virion components affect pathogenicity against different host larvae species.

IMPORTANCE: Different pathogenic processes of a virus in different hosts are related to the host individual differences, which makes the virus undergoes different survival pressures. Here, we found that the virions of an insect virus, Heliothis virescens ascovirus 3h (HvAV-3h), had different protein composition when they were purified from different host larval species. These "adaptive changes" of the virions were analyzed in detail in this study, which mainly included the differences of the protein composition of virions and the differences in affinity between virions and different host proteins. The results of this study revealed the flexible changes of viruses to help themselves adapt to different hosts. Also, these interesting findings can provide new insights to improve our understanding of virus adaptability and virulence differentiation caused by the adaptation process.

3H-31, A Non-structural Protein of Heliothis virescens ascovirus 3h, Inhibits the Host Larval Cathepsin and Chitinase Activities.

3h-31 of Heliothis virescens ascovirus 3h (HvAV-3h) is a highly conserved gene of ascoviruses. As an early gene of HvAV-3h, 3h-31 codes for a non-structural protein (3H-31) of HvAV-3h. In the study, 3h-31 was initially transcribed and expressed at 3 h post-infection (hpi) in the infected Spodoptera exigua fat body cells (SeFB). 3h-31 was further inserted into the bacmid of Autographa californica nucleopolyhedrovirus (AcMNPV) to generate an infectious baculovirus (AcMNPV-31). In vivo experiments showed that budded virus production and viral DNA replication decreased with the expression of 3H-31, and lucent tubular structures were found around the virogenic stroma in the AcMNPV-31-infected SeFB cells. In vivo, both LD50 and LD90 values of AcMNPV-31 were significantly higher than those of the wild-type AcMNPV (AcMNPV-wt) in third instar S. exigua larvae. An interesting finding was that the liquefaction of the larvae killed by the infection of AcMNPV-31 was delayed. Chitinase and cathepsin activities of AcMNPV-31-infected larvae were significantly lower than those of AcMNPV-wt-infected larvae. The possible regulatory function of the chitinase and cathepsin for 3H-31 was further confirmed by RNAi, which showed that larval cathepsin activity was significantly upregulated, but chitinase activity was not significantly changed due to the RNAi of 3h-31. Based on the obtained results, we assumed that the function of 3H-31 was associated with the inhibition of host larval chitinase and cathepsin activities, so as to restrain the hosts in their larval stages.

Novel strategies for the biocontrol of noctuid pests (Lepidoptera) based on improving ascovirus infectivity using Bacillus thuringiensis.

Identifying novel biocontrol agents and developing new strategies are urgent goals in insect pest biocontrol. Ascoviruses are potential competent insect viruses that may be developed into bioinsecticides, but this aim is impeded by their poor oral infectivity. To improve the per os infectivity of ascovirus, Bacillus thuringiensis kurstaki (Btk) was employed as a helper to damage the midgut of lepidopteran larvae (Helicoverpa armigera, Mythimna separata, Spodoptera frugiperda, and S. litura) in formulations with Heliothis virescens ascovirus isolates (HvAV-3h and HvAV-3j). Btk and ascovirus mixtures (Btk/HvAV-3h and Btk/HvAV-3j) were fed to insect larvae (3rd instar). With the exception of S. frugiperda larvae, which exhibited low mortality after ingesting Btk, the larvae of the other tested species showed three types of response to feeding on the formulas: type I, the tested larvae (H. armigera) were killed by Btk infection so quickly that insufficient time and resources remained for ascoviral invasion; type II, both Btk and the ascovirus were depleted by their competition, such that neither was successfully released or colonized the tissue; type III, Btk was eliminated by the ascovirus, and the ascovirus achieved systemic infection in the tested larvae. The feeding of Btk/ascovirus formulas led to a great reduction in larval diet consumption and resulted in a significant decrease in the emergence rate of H. armigera, M. separata, and S. litura larvae, which suggested that the formulas exerted marked oral control effects on both the contemporary individuals and the next generation of these tested pest species.

Expression of CD44 and the survival in glioma: a meta-analysis.

BACKGROUND: Higher tumor expression of CD44, a marker of cancer stem cells (CSCs), is associated with poor overall survival (OS) in various cancers. However, the association between CD44 and poor OS remains inconsistent in glioma. We aimed to evaluate the potential predictive role of CD44 for prognosis of glioma patients in a meta-analysis. METHODS: Observational studies comparing OS of glioma patients according to the level of CD44 were identified through searching PubMed, Embase, and Cochrane's Library databases. Meta-analyses were performed with a random- or fixed-effect model according to the heterogeneity. Subgroup analyses were performed to evaluate the influences of study characteristics. RESULTS: Eleven retrospective cohort studies were included. Results showed that increased CD44 expression in tumor predicted poor OS in glioma patients (hazard ratio [HR]: 1.42, 95% confidence interval [CI]: 1.02-1.97, P=0.04). Subgroup analyses showed that higher tumor CD44 expression significantly predicted poor OS in patients with World Health Organization (WHO) stages II-III glioma (HR: 2.99, 95% CI: 1.53-5.89, P=0.002), but not in patients with glioblastoma (HR: 1.26, 95% CI: 0.76-2.08, P=0.47; P for subgroup difference = 0.03). Results were not statistically different between subgroups according to patient ethnicity, sample size, CD44 detection method, CD44 cutoff, HR estimation, univariate or multivariate analysis, or median follow-up durations (P-values for subgroup difference all >0.10). CONCLUSION: Higher tumor expression of CD44 may predict poor survival in patients with glioma, particularly in those with WHO stage II-III glioma.

Glycyrrhizic acid protects juvenile epileptic rats against hippocampal damage through activation of Sirtuin3.

Glycyrrhizic acid (GA) and Sirtuin3 (Sirt3) were both found to be involved in epilepsy (EP), but their interaction was rarely studied. Herein, we aim to investigate the underlying mechanism of GA with the interaction of Sirt3 in juvenile EP rats. The EP model in juvenile rats was established by lithium chloride-pilocarpine and treated with different concentrations of GA, GA + DMSO or GA + 3-TYP [a selective inhibitor of Sirtuin3 (Sirt3)]. The expression of Sirt3, mitochondrial autophagy-related genes (C-III core 1, COX IV, LC3-I, LC3-II), apoptosis-related genes (Bcl-2, Bax, Caspase-3), glutathione (GSH), superoxide dismutase (SOD), malondialchehyche (MDA) and reactive oxygen species (ROS) as well as mitochondrial membrane potential were subsequently detected. The juvenile EP rats treated with GA showed increased level of C-III core 1 and COX IV, increased LC3-I/LC3-II, GSH and SOD, decreased MDA, increased expression of Sirt3, and Bcl-2, and decreased expression of Bax and Caspase-3. However, inhibition of Sirt3 caused reverse results. Collectively, GA could alleviate hippocampal pathological damage, promote mitochondrial autophagy and reduce oxidative stress in juvenile EP rats through activation of Sirt3. Understanding of these mechanisms may allow devising of novel therapeutics for pediatric EP.

Synthesis of nano-sized urchin-shaped LiFePO4 for lithium ion batteries.

In this article, the facile synthesis of sea urchin-shaped LiFePO4 nanoparticles by thermal decomposition of metal-surfactant complexes and application of these nanoparticles as a cathode in lithium ion secondary batteries is demonstrated. The advantages of this work are a facile method to synthesize interesting LiFePO4 nanostructures and its synthetic mechanism. Accordingly, the morphology of LiFePO4 particles could be regulated by the injection of oleylamine, with other surfactants and phosphoric acid. This injection step was critical to tailor the morphology of LiFePO4 particles, converting them from nanosphere shapes to diverse types of urchin-shaped nanoparticles. Electron microscopy analysis showed that the overall dimension of the urchin-shaped LiFePO4 particles varied from 300 nm to 2 µm. A closer observation revealed that numerous thin nanorods ranging from 5 to 20 nm in diameter were attached to the nanoparticles. The hierarchical nanostructure of these urchin-shaped LiFePO4 particles mitigated the low tap density problem. In addition, the nanorods less than 20 nm attached to the edge of urchin-shaped nanoparticles significantly increased the pathways for electronic transport.

Effects of ionic liquid molecules in hybrid PbS quantum dot-organic solar cells.

We investigated the effect of ionic liquid molecules (ILMs) in hybrid quantum dot-organic solar cells (HyQD-OSCs). The insertion of an ILM layer between PbS and phenyl-C61-butyric acid methyl ester (PCBM) can shift the band edge of PCBM closer to the vacuum level of PbS due to spontaneous dipole polarization. Because of this new architecture, improvements in device performance were achieved, including increases in open-circuit voltage (VOC, from 0.41 V to 0.49 V), fill factor (FF, from 0.48 to 0.59), and power conversion efficiency (PCE, from 1.62% to 2.21%), compared to reference devices under AM 1.5G illumination at 100 mW cm(-2). We observed that treatment of the PbS layer with ILMs causes a significant increase in work function from 3.58 eV to 3.93 eV. Furthermore, the ILMs layer minimizes the contact resistance between PbS and PCBM due to the improved compatibility between the two layers, confirmed as a decrease in charge transfer resistance, as measured by electrical impedance spectroscopy.