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Heterosigma akashiwo is a harmful algal bloom species that causes significant detrimental effects on marine ecosystems worldwide. The algicidal bacterium Pseudalteromonas sp. LD-B1 has demonstrated potential effectiveness in mitigating these blooms. However, the molecular mechanisms underlying LD-B1’s inhibitory effects on H. akashiwo remain poorly understood. In this study, we employed the comprehensive methodology, including morphological observation, assessment of photosynthetic efficiency (Fv/Fm), and transcriptomic analysis, to investigate the response of H. akashiwo to LD-B1. Exposure to LD-B1 resulted in a rapid decline of H. akashiwo's Fv/Fm ratio, with cells transitioning to a rounded shape within 2 hours, subsequently undergoing structural collapse and cytoplasmic leakage. Transcriptomic data revealed sustained downregulation of photosynthetic genes, indicating impaired functionality of the photosynthetic system. Additionally, genes related to the respiratory electron transfer chain and antioxidant defenses were consistently downregulated, suggesting prolonged oxidative stress beyond the cellular antioxidative capacity. Notably, upregulation of autophagy-related genes was observed, indicating autophagic responses in the algal cells. This study elucidates the molecular basis of LD-B1's algicidal effects on H. akashiwo, advancing our understanding of algicidal mechanisms and contributing to the development of effective strategies for controlling harmful algal blooms.

With the proposal of ''Carbon peaking and carbon neutrality'', Adiabatic Compressed Air Energy Storage (A-CAES) has emerged as a significant component within China's energy storage infrastructure. But its thermodynamic efficiency and economical return need yet to be raised. The present paper proposed a modified system coupling with thermal power plant to utilize the excess compression heat. Utilizing advanced transient modeling software, an A-CAES plant is modeled and validated. The operation performance of the coupled system is compared with non-coupled system, which shows that the system efficiency is raised from 54.8 % to 76.7 % and the investment return rate is improved from 9.18 % to 10.43 %.

Clock noise is one of the dominant noises in the space-borne gravitational wave (GW) detection. To suppress this noise, the clock noise-calibrated time-delay-interferometry (TDI) technique is proposed. In this technique, an inter-spacecraft clock tone transfer chain is necessary to obtain the comparison information of the clock noises in two spacecraft, during which an electro-optic-modulator (EOM) is critical and used to modulate the clock noise to the laser phase. Since the EOM sideband modulation process introduces the extra modulation noise, it may limit the experimental demonstration of the suppression effect of the clock noise, and further affect the space-borne GW detection. To solve this problem, it is significant to put forward the modulation noise requirement and test whether the experimental components meet or not. In this work, based on the typical Michelson TDI algorithm and the fundamental noise requirement of GW detectors, the analytic expression of the modulation noise requirement is strictly derived, relaxing the specification compared to the commonly used rough assessments. Furthermore, a method is provided to experimentally test EOM modulation noise, and a commercial EOM (iXblue-NIR-10 GHz) is tested. The experimental results show that it can meet the requirement of the typical GW detection mission LISA in the whole scientific frequency bandwidth by taking the optimal combination of the data streams.

In this work, we have built an experimental setup to simulate the clock noise transmission between two spacecrafts, and further demonstrated the extraction of picometer level signal drowned by the large laser frequency noise and clock noise with the data post-processing method. Laser frequency noise is almost eliminated by using the idea of time-delay interferometry (TDI) to construct an equal arm interferometer. Clock asynchronism and clock jitter noise are significantly suppressed by laser sideband transmitting the clock noise with an electro-optic modulator (EOM). Experimental results show a reduction in laser frequency noise by approximately 105 and clock noise by 102, recovering a weak displacement signal with an average amplitude about 60 picometer and period 1 s. This work has achieved the principle verification of the noise reduction function of TDI technique to some extent, serving the data processing research of space-borne gravitational wave detection.

Aluminum/Polytetrafluoroethylene (Al/PTFE) reactive material occurs chemical reaction and release a large amount of energy under the impact load, which has the dual characteristics of strength and energy release, so it can be applied to the attack of confined space targets to enhance the damage effect on the target. In order to study the dynamic strength of enhanced Al/PTFE and the real-time impact release energy, based on the traditional formula Al/PTFE (26.5%/73.5%), enhanced Al/PTFE reactive material specimens were prepared by cold pressing and rapid cooling processes, and the dynamic mechanical properties of the specimens were tested by the Split Hopkinson Pressure Bar (SHPB) testing system. The experiments have been conducted by using two-stage light gas gun loading system combining with the impact release energy related testing system under vacuum condition. Meanwhile, the evolutionary process of reaction product was numerically simulated by ANSYS/Fluent, and the boundary conditions of the numerical simulation were defined by self-programmed UDF subroutine. Experiments, theoretical analysis and numerical simulation were adopted to obtain the real time energy release of Al/PTFE reactive materials at different impact velocities. The results show that the maximum dynamic failure strength of the enhanced Al/PTFE reactive projectile is 126 MPa, and the strain rate hardening phenomenon and viscoelastic effect are exhibited when the strain rate is in the range of 1500 ∼ 3000 s−1. When the strain rate is in the range of 3000 ∼ 4000 s−1, the specimen is insensitive to strain rate. When the impact velocities are 2.30 km/s and 2.54 km/s, the energies that the reactive projectiles release are 8.36 kJ/g and 8.38 kJ/g, respectively, and the reactive material reacts completely. When the impact velocities are 1.64 km/s, 1.80 km/s and 1.94 km/s, the projectiles have not fully reacted. The reactive degree of the reactive projectile increases with the increase of the impact velocity. For the complete reaction of Al/PTFE reactive projectile, the critical impact velocity of the enhanced reactive material is between 1.94 km/s and 2.30 km/s.

In order to clarify the electromechanical coupling characteristics of polymer materials and extend their applications in MEMS (Micro-electromechanical Systems), electromechanical responses of PDMS (Polydimethylsiloxane) with different electrodes and thicknesses under different loading conditions have been performed experimentally and numerically. Basic electrical parameters measurement and quasi-static tensile experiment of PDMS specimens were conducted. Furthermore, the dynamic mechanical properties and polarization voltage of PDMS with different electrodes and thicknesses under different loading conditions have been studied by Split Hopkinson Pressure Bar (SHPB) system integrating with electrical output measuring system. Beyond that, Abaqus/Explicit numerical simulation of PDMS specimen under different loading conditions was carried out based on Yeoh viscoelastic model and Prony series, then the strain gradient and the flexoelectric coefficients were obtained. The results show that the maximum stress of PDMS increases with increasing of loading speed and decreases with increasing of thickness, the maximum polarization voltage increases with increasing of strain rate, the maximum polarization voltages of PDMS with “C” electrode and “+” electrode are about 14 times of that with circular electrode, the flexoelectric coefficients of PDMS are within the range of 10−11–10−9C/m.

Summary: In this study, we obtained the whole genome sequence of GCRV-DY197 and investigated the localization, post-translational modifications, and host interactions of the 11 viral proteins encoded by GCRV-DY197 in grass carp ovary (GCO) cells. The whole genome sequence is 24,704 kb and contains 11 segments (S1–S11). Subcellular localization showed that the VP1, VP2, VP3, VP5, VP56, and VP35 proteins were localized in both cytoplasm and nucleus, whereas the NS79, VP4, VP41, VP6, and NS38 proteins were localized in the cytoplasm. The NS79 and NS38 proteins were phosphorylated, and the ubiquitination modification sites were identified in VP41 and NS38. An interaction network containing 9 viral proteins and 140 host proteins was also constructed. These results offer a theoretical basis for an in-depth understanding of the biochemical characteristics and pathogenic mechanism of GCRV-II.

Quantitative Real-time PCR (qRT-PCR) is one of the most widely used methods for gene quantification because it is extremely sensitive, can be highly sequence specific, and has high precision while being easily reproducible in samples. The stability of the reference genes used for data normalization is crucial for exact experimental results and conclusions. In this study, qRT-PCR was used to analyze the expression of eight candidate reference genes including β-actin (ACTB), α-tubulin (TUBA), Elongation factor-1-α (EF1A), Glyceraldehyde-3-phosphate dehydrogenase (GAPDH1, GAPDH2), Hypoxanthine guanine phosphoribosyl transferase1 (HPRT), Ribosomal protein L7 (RPL7), and RNA polymerase II (RNA PoL Ⅱ) in largemouth bass. The expression and stability of above genes were evaluated among eight tissues with or without largemouth bass virus (LMBRaV) infection and assessed using BestKeeper, GeNorm, NormFinder statistical softwares and comparative Ct method, and then analyzed the comprehensive ranking by ReFinder. Our results showed that ACTB was identified as the most suitable genes of different tissues, while TUBA was ranked as the best reference gene in tissues infection with LMBRaV. To verify the screened reference genes, the expression pattern of IFN in spleen during LMBRaV infection was examined. This study provides useful information for gene expression characterization using qRT-PCR, which will benefit for future studies of gene regulation in largemouth bass.

Largemouth bass ranavirus (LMBRaV), a double-stranded DNA (dsDNA) virus, leads to considerable mortality and significant economic impacts in the largemouth bass (Micropterus salmoides) aquaculture sector. This study evaluated and screened compounds from Chinese herbs for their activity against LMBRaV. Esculin exhibited the highest rate (73 %) of inhibition on LMBRaV major capsid protein (MCP) gene expression at a concentration of 60 mg/L in a cellular environment. It also significantly reduced the cytopathic effect (CPE), protecting infected cells from LMBRaV-induced nuclear damage and hindering LMBRaV infection by modulating viral entry mechanisms. For in vivo study, esculin increased the survival rate of LMBRaV-infected largemouth bass by 60.0 % and 53.3 %, in prevention experiment and treatment experiment, respectively. Concurrently, esculin significantly reduced viral loads and induced the upregulation of antiviral-associated genes, indicating its potential for immunoregulation. In summary, esculin holds potential for both preventing and treating LMBRaV infections in the aquaculture context.

B-cell lymphoma-2 (BCL-2) superfamily molecules play crucial roles in mitochondrial apoptosis induced by Chinese giant salamander iridovirus (GSIV). As an anti-apoptotic molecule in the BCL-2 family, the molecular mechanism of Bcl-w during GSIV infection remains unknown. In this study, we characterized for the first time an amphibian Bcl-w from Chinese giant salamander Andrias davidianus (AdBcl-w), and its function and regulatory mechanism during GSIV infection were investigated. AdBcl-w possesses the conserved structural features of Bcl-w and shares 35–54% sequence identities with other Bcl-w. mRNA expression of AdBcl-w was most abundant in liver and muscle. The AdBcl-w mRNA expression was regulated during GSIV infection. Western blotting assays revealed that the level of Bcl-w protein was downregulated markedly as the infection progresses. Confocal microscopy showed that overexpressed AdBcl-w was translocated to the mitochondria after infection with GSIV. Flow cytometry analysis demonstrated that compared with control, the apoptotic progress in cells transfected with AdBcl-w was reduced while that in cells transfected with AdBcl-w siRNA was enhanced. The number of virus major capsid protein gene copies was lower and protein synthesis was reduced in AdBcl-w overexpressing cells. In addition, AdBcl-w could bind directly to the pro-apoptotic molecule AdBak, while this interaction was weakened with GSIV infection. Moreover, p53 level was reduced and the mRNA expression levels of crucial regulatory molecules in the p53 pathway were regulated in AdBcl-w overexpressing cells during GSIV infection. These results suggested that AdBcl-w inhibit GSIV replication by regulating the virus induced mitochondrial apoptosis.

Fusion-associated small transmembrane (FAST) proteins can promote cell fusion, alter membrane permeability and trigger apoptosis to promote virus proliferation in orthoreoviruses. However, it is unknown whether FAST proteins perform these functions in aquareoviruses (AqRVs). Non-structural protein 17 (NS17) carried by grass carp reovirus Honghu strain (GCRV-HH196) belongs to the FAST protein family, and we preliminarily explored its relevance to virus infection. NS17 has similar domains to FAST protein NS16 of GCRV-873, comprising a transmembrane domain, a polybasic cluster, a hydrophobic patch and a polyproline motif. It was observed in the cytoplasm and the cell membrane. Overexpression of NS17 enhanced the efficiency of cell-cell fusion induced by GCRV-HH196 and promoted virus replication. Overexpression of NS17 also led to DNA fragmentation and reactive oxygen species (ROS) accumulation, and it triggered apoptosis. The findings illuminate the functions of NS17 in GCRV infection, and provide a reference for the development of novel antiviral strategies.

White abdominal disease is one of the major diseases in Chinese soft-shelled turtle (Pelodiscus sinensis, SST) aquaculture. To clarify the pathological characteristics of white abdominal disease, 24 SSTs with typical white abdominal symptoms were collected from a farm in Hubei Province, China. First, the pathogens of the SSTs were detected, including viruses and bacteria. No virus was detected. A variety of bacteria have been isolated. The pathological characteristics of the diseased SSTs were then studied using hematological analysis, histopathological observation, intestinal microbial analysis, and immunity-related gene expression. Compared with the healthy SST, the number of red blood cells reduced from 1.2 ± 0.5 × 1013 /L to 1.5 ± 0.2 × 1012 /L in the diseased SSTs. Meanwhile, the number of white blood cells increased by nearly four-fold (from 1.8 ± 0.5 × 1010 /L to 7.1 ± 3.5 × 1010 /L). In the diseased SSTs, the liver displayed several abnormalities, such as hepatocyte vacuolation and changes in nonparenchymal tissue. Some glomeruli of the kidney showed necrosis and disintegration. Cavities and loose muscles were observed in the gastric muscle layer. The blurred boundary between the red pulp and white pulp of the spleen was accompanied by massive invasion of inflammatory cells. Significant differences were detected in the relative abundances of Proteobacteria (from 29% to 7%) and Fusobacteria (from 12% to 28%) between the diseased and healthy SSTs. Compared with those in the healthy SSTs, the gene expression levels of toll-like receptor 2(TLR), TLR3, and myeloid differentiation primary response 88 (MyD88) were increased, by more than 4-fold, 7-fold, and 5-fold, respectively (P

Coreius guichenoti is a rare fish found in the upper reaches of the Yangtze River in China and has significant ecological and economic value. In this study, a bacterial strain (F416) was isolated from diseased C. guichenoti and was identified as Staphylococcus warneri. Its median lethal dose (LD50) was 6.31 × 106 colony-forming units/mL. Histopathological observation revealed that substantial inflammatory cell infiltration occurred in the tissues of diseased fish, and the muscle fibers had lesions. Strain F416 is resistant to aminoglycosides, sulfonamides, and tetracyclines used in aquaculture. This is the first study, to the best of our knowledge, to isolate S. warneri from cultured C. guichenoti and to describe its biological characteristics and the histopathological changes that cause disease in C. guichenoti post-infection.

Intestinal microbiota influence host health. Numerous pathogens have been reported in crayfish (Procambarus clarkii) breeding systems. White spot disease, which is caused by white spot syndrome virus (WSSV), is the most severe disease observed in crayfish aquaculture systems. The present study investigated changes in intestinal morphology and gut microbiota in crayfish under WSSV infection. WSSV infection caused intestinal villi and hepatopancreas damage. In addition, intestinal microbiota diversity and richness decreased significantly under WSSV infection, and some functions of the intestinal microbiota were altered. Proteobacteria and Firmicutes abundance increased and decreased significantly, respectively, under WSSV infection. At the genus level, the relative abundance of an opportunistic pathogen, Aeromonas, increased significantly, and the abundances of Acinetobacter and Kurthia decreased significantly, in WSSV-infected crayfish. Additionally, according to the results of metagenomics analyses using PICRUSt, the altered microbiota was mainly linked to metabolism, diseases, environmental information processing, organismal systems, and cellular processes. Microbiome phenotype analyses based on BugBase revealed that the potential pathogenicity of intestinal flora in WSSV-infected crayfish was higher than in healthy crayfish. Overall, WSSV infection influenced intestinal and hepatopancreatic morphology, in addition to gut microbiota structure in crayfish.