The Impact of Oxygen Content in O-Doped MoS2 on the Kinetics of Polysulfide Conversion in Li-S Batteries.

Polysulfide shuttle and sluggish sulfur redox kinetics remain key challenges in lithium-sulfur batteries. Previous researches have shown that introducing oxygen into transition metal sulfides helps to capture polysulfides and enhance their conversion kinetics. Based on this, further investigations are conducted to explore the impact of oxygen doping levels on the physical-chemical properties and electrocatalytic performance of MoS2. The findings reveal that MoS2 doped with high-content oxygen exhibits enhanced conductivity and polysulfides conversion kinetics compared to MoS2 with low-content oxygen doping, which can be attributed to the alteration of crystal structure from 2H-phase to the 1T-phase, the introduction of increased Li-O interactions, and the effect of defects resulting from high-oxygen doping. Consequently, the lithium-sulfur batteries using high-oxygen doped MoS2 as a catalyst deliver a high discharge capacity of 1015 mAh g-1 at 0.25C and maintain 78.5% capacity after 300 more cycles. Specifically, lithium-sulfur batteries employing paper-based electrodedemonstrate an areal capacity of 3.91 mAh cm-2 at 0.15C, even with sulfur loading of 4.1 mg cm-2 and electrolyte of 6.7 µL mg-1. These results indicate that oxygen doping levels can modify the properties of MoS2, and high-oxygen doped MoS2 shows promise as an efficient catalyst for lithium-sulfur batteries.

Robust topological insulating property in C2X-functionalized III-V monolayers.

Two-dimensional topological insulators (TIs) show great potential applications in low-power quantum computing and spintronics due to the spin-polarized gapless edge states. However, the small bandgap limits their room-temperature applications. Based on first-principles calculations, a series of C2X (X = H, F, Cl, Br and I) functionalized III-V monolayers are investigated. The nontrivial bandgaps of GaBi-(C2X)2, InBi-(C2X)2, TlBi-(C2X)2and TlSb-(C2X)2are found to between 0.223 and 0.807 eV. For GaBi-(C2X)2and InBi-(C2X)2, the topological insulating properties originate from thes-px,yband inversion induced by the spin-orbital coupling (SOC) effect. While for TlBi-(C2X)2and TlSb-(C2X)2, the topological insulating properties are attributed to the SOC effect-induced band splitting. The robust topological characteristics are further confirmed by topological invariantsZ2and the test under biaxial strain. Finally, two ideal substrates are predicted to promote the applications of these TIs. These findings indicate that GaBi-(C2X)2, InBi-(C2X)2, TlBi-(C2X)2and TlSb-(C2X)2monolayers are good candidates for the fabrication of spintronic devices.

High-pressure effects on the electronic properties and photoluminescence of Ag-doped CsCu2I3.

CsCu2I3 is a popular lead-free metal halide perovskite with good thermal and air stability. To facilitate its applications in optoelectronics, Ag doping and high pressure are employed in this work to improve the optoelectronic properties of CsCu2I3. Using first-principles calculations and experiments, the structural phase change of 10% Ag-doped CsCu2I3 is found to occur at about 4.0 GPa. This reveals the regulation of band structures by hydrostatic pressure. In addition, the high pressure not only increases the emission energy of photoluminescence of 10% Ag-doped CsCu2I3 by more than 0.2 eV, but also increases the emission intensity by multiple times. Finally, the origin of luminescence in 10% Ag-doped CsCu2I3 is attributed to the I vacancies. This work provides insight into the structure and optoelectronic properties of 10% Ag-doped CsCu2I3, and offers significant guidance for the design and manufacturing of future luminescence devices.

Oxybutynin ameliorates LPS-induced inflammatory response in human bladder epithelial cells.

Urinary tract infection (UTI) mainly results from bacterial infections in the urinary tract and markedly impacts the normal lives of millions of patients worldwide. The infection and damage to urethral epithelial cells is the first and key step of UTI development and is a critical target for treating clinical UTI. Oxybutynin, an agent for treating urinary incontinence, is recently claimed with protective effects on bladder ultrastructure. Our study will assess the impact of Oxybutynin on inflammation in lipopolysaccharide (LPS)-stimulated bladder epithelial cells. Bladder epithelial T24 cells were treated with 1 µg/mL LPS with or without 10 and 20 µM Oxybutynin for 24 h. Increased levels of oxidative stress (OS) biomarkers, such as reactive oxygen species, 8-hydroxy-2'-deoxyguanosine, malondialdehyde, as well as upregulated inducible nitric oxide synthase and promoted release of nitric oxide, were observed in LPS-managed T24 cells, all of which were signally suppressed by Oxybutynin. Furthermore, severe inflammatory responses, including enhanced release of cytokines, upregulated matrix metallopeptidase-2 (MMP-2) and MMP-9, and raised monocyte chemoattractant protein-1 level, were found in LPS-challenged T24 cells, which were markedly reversed by Oxybutynin. Moreover, the activated toll-1ike receptor 4/nuclear factor-κB pathway observed in LPS-managed T24 cells was repressed by Oxybutynin. Collectively, Oxybutynin mitigated LPS-induced inflammatory response in human bladder epithelial cells.

An esculentin-1 homolog from a dark-spotted frog (Pelophylax nigromaculatus) possesses antibacterial and immunoregulatory properties.

BACKGROUND: Esculentin-1, initially discovered in the skin secretions of pool frogs (Pelophylax lessonae), has demonstrated broad-spectrum antimicrobial activity; however, its immunomodulatory properties have received little attention. RESULTS: In the present study, esculentin-1 cDNA was identified by analysing the skin transcriptome of the dark-spotted frog (Pelophylax nigromaculatus). Esculentin-1 from this species (esculentin-1PN) encompasses a signal peptide, an acidic spacer peptide, and a mature peptide. Sequence alignments with other amphibian esculentins-1 demonstrated conservation of the peptide, and phylogenetic tree analysis revealed its closest genetic affinity to esculentin-1P, derived from the Fukien gold-striped pond frog (Pelophylax fukienensis). Esculentin-1PN transcripts were observed in various tissues, with the skin exhibiting the highest mRNA levels. Synthetic esculentin-1PN demonstrated antibacterial activity against various pathogens, and esculentin-1PN exhibited bactericidal activity by disrupting cell membrane integrity and hydrolyzing genomic DNA. Esculentin-1PN did not stimulate chemotaxis in RAW264.7, a murine leukemic monocyte/macrophage cell line. However, it amplified the respiratory burst and augmented the pro-inflammatory cytokine gene (TNF-α and IL-1ß) expression in RAW264.7 cells. CONCLUSIONS: This novel finding highlights the immunomodulatory activity of esculentin-1PN on immune cells.

An Inhibitor-Monitorable Single-Tube Duplex Quantitative Real-Time PCR Assay for the Detection of 'Candidatus Liberibacter asiaticus'.

Huanglongbing (HLB) is a citrus infectious disease caused by 'Candidatus Liberibacter' spp. Recently, it has begun to spread rapidly worldwide, causing significant losses to the citrus industry. Early diagnosis of HLB relies on quantitative real-time PCR assays. However, the PCR inhibitors found in the nucleic acid extracted from plant materials pose challenges for PCR assays because they may result in false-negative results. Internal standard (IS) can be introduced to establish a single-tube duplex PCR for monitoring the influence of the PCR inhibitor, but it also brings the risk of false-negative results because the amplification of IS may compete with the target. To solve this problem, we proposed a mutation-enhanced single-tube duplex PCR (mSTD-PCR) containing IS with mutant-type primers. By introducing the 3'-terminal mutation in the primer of IS to weaken its amplification reaction and its inhibition of 'Candidatus Liberibacter asiaticus' (CLas) detection, the sensitivity and quantitative accuracy of CLas detection will not be affected by IS. In evaluating the sensitivity of CLas detection using simulation samples, the mSTD-PCR showed consistent sensitivity at 25 copies per test compared with the single-plex CLas assay. The detection result of 30 leaves and 30 root samples showed that the mSTD-PCR could recognize false-negative results caused by the PCR inhibitors and reduce workload by 48% compared with the single-plex CLas assay. Generally, the proposed mSTD-PCR provides a reliable, efficient, inhibitor-monitorable, quantitative screening method for accurately controlling HLB and a universal method for establishing a PCR assay for various pathogens.

BamA-targeted antimicrobial peptide design for enhanced efficacy and reduced toxicity.

The emergence of drug-resistant superbugs has necessitated a pressing need for innovative antibiotics. Antimicrobial peptides (AMPs) have demonstrated broad-spectrum antibacterial activity, reduced susceptibility to resistance, and immunomodulatory effects, rendering them promising for combating drug-resistant microorganisms. This study employed computational simulation methods to screen and design AMPs specifically targeting ESKAPE pathogens. Particularly, AMPs were rationally designed to target the BamA and obtain novel antimicrobial peptide sequences. The designed AMPs were assessed for their antibacterial activities, mechanisms, and stability. Molecular docking and dynamics simulations demonstrated the interaction of both designed AMPs, 11pep and D-11pep, with the ß1, ß9, ß15, and ß16 chains of BamA, resulting in misfolding of outer membrane proteins and antibacterial effects. Subsequent antibacterial investigations confirmed the broad-spectrum activity of both 11pep and D-11pep, with D-11pep demonstrating higher potency against resistant Gram-negative bacteria. D-11pep exhibited MICs of 16, 8, and 32 µg/mL against carbapenem-resistant Escherichia coli, carbapenem-resistant Pseudomonas aeruginosa, and multi-drug-resistant Acinetobacter baumannii, respectively, with a concomitant lower resistance induction. Mechanism of action studies confirmed that peptides could disrupt the bacterial outer membrane, aligning with the findings of molecular dynamics simulations. Additionally, D-11pep demonstrated superior stability and reduced toxicity in comparison to 11pep. The findings of this study underscore the efficacy of rational AMP design that targets BamA, along with the utilization of D-amino acid replacements as a strategy for developing AMPs against drug-resistant bacteria.

Disulfiram reduces the severity of mouse acute pancreatitis by inhibiting RIPK1-dependent acinar cell necrosis.

Acute pancreatitis (AP) is a frequent abdominal inflammatory disease. Despite the high morbidity and mortality, the management of AP remains unsatisfactory. Disulfiram (DSF) is an FDA-proved drug with potential therapeutic effects on inflammatory diseases. In this study, we aim to investigate the effect of DSF on pancreatic acinar cell necrosis, and to explore the underlying mechanisms. Cell necrosis was induced by sodium taurocholate or caerulein, AP mice model was induced by nine hourly injections of caerulein. Network pharmacology, molecular docking, and molecular dynamics simulation were used to explore the potential targets of DSF in protecting against cell necrosis. The results indicated that DSF significantly inhibited acinar cell necrosis as evidenced by a decreased ratio of necrotic cells in the pancreas. Network pharmacology, molecular docking, and molecular dynamics simulation identified RIPK1 as a potent target of DSF in protecting against acinar cell necrosis. qRT-PCR analysis revealed that DSF decreased the mRNA levels of RIPK1 in freshly isolated pancreatic acinar cells and the pancreas of AP mice. Western blot showed that DSF treatment decreased the expressions of RIPK1 and MLKL proteins. Moreover, DSF inhibited NF-κB activation in acini. It also decreased the protein expression of TLR4 and the formation of neutrophils extracellular traps (NETs) induced by damage-associated molecular patterns released by necrotic acinar cells. Collectively, DSF could ameliorate the severity of mouse acute pancreatitis by inhibiting RIPK-dependent acinar cell necrosis and the following formation of NETs.

Computational biology-based study of the molecular mechanism of spermidine amelioration of acute pancreatitis.

Acute pancreatitis (AP) is an acute inflammatory gastrointestinal disease, the mortality and morbility of which has been on the increase in the past years. Spermidine, a natural polyamine, has a wide range of pharmacological effects including anti-inflammation, antioxidation, anti-aging, and anti-tumorigenic. This study aimed to investigate the reliable targets and molecular mechanisms of spermidine in treating AP. By employing computational biology methods including network pharmacology, molecular docking, and molecular dynamics (MD) simulations, we explored the potential targets of spermidine in improving AP with dietary supplementation. The computational biology results revealed that spermidine had high degrees (degree: 18, betweenness: 38.91; degree: 18, betweenness: 206.41) and stable binding free energy (ΔGbind: - 12.81 ± 0.55 kcal/mol, - 15.00 ± 1.00 kcal/mol) with acetylcholinesterase (AchE) and serotonin transporter (5-HTT). Experimental validation demonstrates that spermidine treatment could reduce the necrosis and AchE activity in pancreatic acinar cells. Cellular thermal shift assay (CETSA) results revealed that spermidine could bind to and stabilize the 5-HTT protein in acinar cells. Moreover, spermidine treatment impeded the rise of the expression of 5-HTT in pancreatic tissues of caerulein induced acute pancreatitis mice. In conclusion, serotonin transporter might be a reliable target of spermidine in treating AP. This study provides new idea for the exploration of potential targets of natural compounds.

Three-dimensional quantitative structural-activity relationship and molecular dynamics study of multivariate substituted 4-oxyquinazoline HDAC6 inhibitors.

3D-QSAR models were established by collecting 46 multivariate-substituted 4-oxyquinazoline HDAC6 inhibitors. The relationship of molecular structure and inhibitory activity was studied by comparative molecular field analysis (CoMFA) and comparative molecular similarity index analysis (CoMSIA). The results showed the models established by CoMFA (q2 = 0.590, r2 = 0.965) and CoMSIA (q2 = 0.594, r2 = 0.931) had good prediction ability. At the same time, 3D-QSAR models met the internal verification, external verification and AD test. Ten new compounds were designed based on CoMFA and CoMSIA contour maps and their pharmacokinetic/toxic properties (ADME/T) were evaluated. It was found that most compounds have well safety profile and pharmacokinetic property. Then, we explored the interaction between HDAC6 and compounds by molecular docking. The results showed that the binding mode of the new compounds with HDAC6 was the same as the template compound 46, and the hydrogen bond and hydrophobic bond played a vital role in the binding process. Molecular dynamics simulation results showed that residues Ser531, His574 and Tyr745 played key roles in the binding process. All newly designed compounds had lower energy gap and binding energy than compound 46 according to DFT analysis and free energy analysis. This study provided a theoretical reference for designing compounds of higher activity and a new idea for the development of novel HDAC6 inhibitors.

Bioactive Dimeric Diterpenoids from Taiwania cryptomerioides (Hayata) and Their Biological Activities.

Taiwania cryptomerioides Hayata is an endangered relict plant belonging to Taxodiaceae, and it is also an endemic plant to China. The decay-resistant of Taiwania timber can provide highly quality wood for building and furniture. Plenty of regenerative of leaves of T. cryptomerioides also has been used as a resource for the discovery of new dimeric diterpenoids. In a search for structurally diverse dimeric diterpenoids and potent bioactive isolates, ten new heterodimeric diterpenoids, taiwaniadducts K-T (1-4, 6, 8-11, and 14), along with five known ones (5, 7, 12, 13, and 15), were isolated from the leaves of T. cryptomerioides. These new compounds were defined by comprehensive spectroscopic analyses, putative biosynthetic pathways, and the values of optical. Biologically, anti-multidrug resistance (MDR) activities of compounds were evaluated. Compounds 4 and 10 exerted a 9.18-fold potentiation effect on bortezmib (BTZ) susceptibility at a tested concentration (20 µM) better than the positive control verapamil. The research of the leaves of T. cryptomerioides not only added the new data to the structural diversity and activities of dimeric diterpenoids but also could provide support for the medical and industrial application of the leaves of this endangered relict plant.

Genome-wide identification and characterization of superoxide dismutases in four oyster species reveals functional differentiation in response to biotic and abiotic stress.

BACKGROUND: Oysters inhabit in the intertidal zone and may be suffered from environmental stresses, which can increase the production of reactive oxygen species (ROS), resulting in mass mortality. Superoxide dismutases (SODs) protect oysters from ROS damage through different mechanisms compared with vertebrates. However, the molecular and functional differentiation in oyster SODs were rarely analyzed. RESULT: In this study, a total of 13, 13, 10, and 8 candidate SODs were identified in the genome of Crassostrea gigas, Crassostrea virginica, Crassostrea hongkongensis, and Saccostrea glomerata respectively. The domain composition, gene structure, subcellular locations, conserved ligands, and cis-elements elucidated the SODs into five groups (Mn-SODs, Cu-only-SODs, Cu/Zn ion ligand Cu/Zn-SOD with enzyme activity, Zn-only-SODs, and no ligand metal ions Cu/Zn-SODs). For single domain Cu/Zn-SODs, only one cytosolic Cu/Zn-SOD (cg_XM_034479061.1) may conserve enzymatic activity while most extracellular Cu/Zn-SOD proteins appeared to lose SOD enzyme activity according to conserved ligand amino acid analysis and expression pattern under biotic and abiotic stress in C. gigas. Further, multi-domain-SODs were identified and some of them were expressed in response to biotic and abiotic stressors in C. gigas. Moreover, the expression patterns of these genes varied in response to different stressors, which may be due to the cis-elements in the gene promoter. CONCLUSION: These findings revealed the most extracellular Cu/Zn-SOD proteins appeared to lose SOD enzyme activity in oysters. Further, our study revealed that only one cytosolic Cu/Zn-SOD (cg_XM_034479061.1) may conserve enzymatic activity of SOD. Moreover, the expression patterns of these genes varied in response to different stressors, which may be due to the cis-elements in the promoter. This study provides important insights into the mechanisms through which oysters adapt to harsh intertidal conditions, as well as potential biomarkers of stress response in related species.

Genomic Insights into the Origin and Evolution of Molluscan Red-Bloodedness in the Blood Clam Tegillarca granosa.

Blood clams differ from their molluscan kins by exhibiting a unique red-blood (RB) phenotype; however, the genetic basis and biochemical machinery subserving this evolutionary innovation remain unclear. As a fundamental step toward resolving this mystery, we presented the first chromosome-level genome and comprehensive transcriptomes of the blood clam Tegillarca granosa for an integrated genomic, evolutionary, and functional analyses of clam RB phenotype. We identified blood clam-specific and expanded gene families, as well as gene pathways that are of RB relevant. Clam-specific RB-related hemoglobins (Hbs) showed close phylogenetic relationships with myoglobins (Mbs) of blood clam and other molluscs without the RB phenotype, indicating that clam-specific Hbs were likely evolutionarily derived from the Mb lineage. Strikingly, similar to vertebrate Hbs, blood clam Hbs were present in a form of gene cluster. Despite the convergent evolution of Hb clusters in blood clam and vertebrates, their Hb clusters may have originated from a single ancestral Mb-like gene as evidenced by gene phylogeny and synteny analysis. A full suite of enzyme-encoding genes for heme synthesis was identified in blood clam, with prominent expression in hemolymph and resembling those in vertebrates, suggesting a convergence of both RB-related Hb and heme functions in vertebrates and blood clam. RNA interference experiments confirmed the functional roles of Hbs and key enzyme of heme synthesis in the maintenance of clam RB phenotype. The high-quality genome assembly and comprehensive transcriptomes presented herein serve new genomic resources for the super-diverse phylum Mollusca, and provide deep insights into the origin and evolution of invertebrate RB.

Ruthenium red attenuates acute pancreatitis by inhibiting MCU and improving mitochondrial function.

Acute pancreatitis (AP) is a common inflammatory disease of the digestive system. Mitochondrial calcium uniporter (MCU) mediates mitochondrial uptake of Ca2+ and plays an important role in calcium homeostasis. However, it is undefined whether AP can be relieved by inhibiting MCU. This study aimed to study the therapeutic potential of Ruthenium red (RuR), a MCU inhibitor, in AP mice model and primary acinar cells. Cell injury and AP mice model was induced by caerulein. RuR alleviated CER-AP evidenced by reduced serum lipase, TNF-α, and pancreatic MPO levels, less severe pancreatic pathology damage, and decreased inflammatory cell infiltration. In freshly isolated pancreatic acinar cells, RuR diminished cell necrosis with effect on suppressing the expression of MCU. RuR also decreased levels of cytosolic calcium and ROS, preventing mitochondrial membrane potential loss, ATP depletion and MPTP opening. The present findings indicate that inhibit MCU by RuR has a beneficial effect in AP by preventing calcium overload, mitochondrial dysfunction, and cell necrosis.

Brønsted Acid-Catalyzed Carbonyl-Olefin Metathesis: Synthesis of Phenanthrenes via Phosphomolybdic Acid as a Catalyst.

Compared with the impressive achievements of catalytic carbonyl-olefin metathesis (CCOM) mediated by Lewis acid catalysts, exploration of the CCOM through Brønsted acid-catalyzed approaches remains quite challenging. Herein, we disclose a synthetic protocol for the construction of a valuable polycycle scaffold through the CCOM with the inexpensive, nontoxic phosphomolybdic acid as a catalyst. The current annulations could realize carbonyl-olefin, carbonyl-alcohol, and acetal-alcohol in situ CCOM reactions and feature mild reaction conditions, simple manipulation, and scalability, making this strategy a promising alternative to the Lewis acid-catalyzed COM reaction.

Transcriptomic identification of key genes in Pacific oysters Crassostrea gigas responding to major abiotic and biotic stressors.

Oysters are commercially important intertidal filter-feeding species. Mass mortality events of oysters often occur due to environmental stresses, such as exposure to fluctuating temperatures, salinity, and air, as well as to metal pollution and pathogen infection. Here, RNA-seq data were used to identify shared and specific responsive genes by differential gene expression analysis and weighted gene co-expression network analysis. A total of 18 up-regulated and 10 down-regulated shared responsive genes were identified corresponding to five different stressors. Total 27 stressor-specific genes for temperature, 11 for salinity, 80 for air exposure, 51 for metal pollution, and 636 for Vibrio mediterranei pathogen stress were identified in oysters. Elongin-ß was identified as a crucial gene for thermal stress response. Some HSP70s were determined to be shared responsive genes while others were specific to thermal tolerance. The proteins encoded by these stress-related genes should be further investigated to characterize their physiological functions. In addition, the uncharacterized proteins and ncRNAs that were identified may be involved in species-specific stress-response and regulatory mechanisms. This study identified specific genes related to stressors relevant to oyster cultivation. These findings provide useful information for new selective breeding strategies using a data driven method.

Genome-wide identification and characteristic analysis of PGRP gene family in Tegillarca granosa reveals distinct immune response of the invasive pathogen.

The peptidoglycan recognition proteins (PGRPs) are conserved innate immune molecular in invertebrates and vertebrates, which play important roles in immune system by recognize the peptidoglycans of bacterial cell walls. Although PGRPs have been extensively characterized in insects, a systematic analysis of PGRPs in bivalves is lacking. In the present study, the phylogenic relationships, gene structures and expression profiles of PGRPs in marine bivalves were analyzed. The results indicated that the most PGRPs of bivalves were predicted to degrade the peptidoglycans and prevent excessive immunostimulation of bacteria. In addition, the results of the present study showed that the protein diversity of PGRPs in most marine bivalves was mainly generated by the alternative splicing of genes, however the alternative splicing of PGRP gene family was absent in Tegillarca granosa. The differences of PGRPs might be related to the genetic and environmental differences of marine bivalves. Spatiotemporal expression profiling in T. granosa suggested that PGRPs play important roles in the immune response of invasive pathogens. The present study describes a comprehensive view of PGRPs in the blood clam T. granosa and provides a foundation for functional characterization of this gene family in innate immune of marine bivalves.

Genome-wide identification and immune response analysis of serine protease inhibitor genes in the blood clam Tegillarca granosa.

Serine protease inhibitors (SPIs) are the main regulators of serine protease activities. In this study, we present a genome-wide identification of SPI genes in T. granosa（TgSPI genes）and their expression characteristics in respond to Vibrio stress. A total of 102 TgSPI genes belonging to eight families, including Serpin, TIL (trypsin inhibitor like cysteine rich domain), Kunitz, Kazal, I84, Pacifastin, WAP (whey acidic protein) and A2M (Alpha-2-macroglobulin) were identified, while no genes belonging to Bowman-Birk, amfpi and Antistasin families were identified. The Kazal family has the most TgSPI genes with 38, and 11 TgSPI genes belong to the mollusc-specific I84 family. The TgSPI genes were found to be randomly distributed on 17 chromosomes with 12 tandem duplicate gene pairs. Expression profiles showed that most TgSPI genes were mainly expressed in immune-related tissues such as hepatopancreas, gill and mantle. In the hepatopancreas, most of TgSPI genes were sensitive to Vibrio stress, 28 and 29 TgSPI genes were up-regulated and down-regulated, respectively. Some up-regulated genes with signal peptides, such as the TgSPIs of I84 family, may act as a mechanism to directly prevent Vibrio from invasion. Six Kazal-type TgSPIs (TgSPI29, 45, 49, 50, 51 and 52) were intracellular proteins and their expression was down-regulated in hemocytes after Vibrio stress. This may have boosted protease activity in hemocytes to the point that more hemoglobin derived peptides were produced and secreted into the hemolymph to exert their anti-Vibrio effects. These findings may provide valuable information for further clarifying the roles of SPIs in the immune defense and will benefit future exploration of the immune function of SPIs in molluscs.

PDIA6 involves the thermal stress response of razor clam, Sinonovacula constricta.

Protein disulfide isomerases A6 (PDIA6), an oxidoreductase and isomerase, catalyzes the oxidation reduction and isomerization of disulfide bonds, and serves as molecular chaperone to prevent the buildup of misfolded proteins under various environmental insults. However, the role of PDIA6 in mollusks remains largely obscure, although its multifunctional protein has been reported in other species under adverse conditions. To fill this gap, we identified PDIA6 from the razor clam Sinonovacula constricta (ScPDIA6) and investigated its expression patterns in response to thermal stress. Tissue distribution showed that the mRNA transcript of ScPDIA6 was ubiquitously expressed in nine tested tissues. Temporal expression profiles by qPCR revealed that ScPDIA6 in the gill and mantle was significantly increased by hyper-thermic treatment. Further, Western blot and immunofluorescence indicated that ScPDIA6 was significantly upregulated by thermal treatment at the protein level. Additionally, the survival test demonstrated that the viability of E. coli cells expressing recombinant ScPDIA6 protein increased at 42 °C compared with empty vector. Overall, these findings suggested that ScPDIA6 may play a pivotal role in counteracting thermal stress. This study will provide valuable reference data resource for understanding the potential role of PDIA6 in mollusks.

The complete mitochondrial genome of Crassostrea hongkongensis from East China Sea indicates species' range may extend northward.

BACKGROUND: Crassostrea hongkongensis is an important mariculture shellfish with a relatively narrow distribution range. Recently, larger wild oysters were identified as C. hongkongensis from Sanmen bay in East China Sea. No natural distribution had been reported for this species here, and its origin remains unknown. METHODS AND RESULTS: We assembled the complete 18,617 bp circular mitochondrial genome of C. hongkongensis from Sanmen bay by next generation sequencing. It included 12 protein-coding genes, 23 tRNAs, and two rRNAs. The A/T content of the mitogenome was higher than its G/C content. Similar values and features were previously found for five other specimens of C. hongkongensis, and were comparable to those of other congeneric species. A phylogenetic analysis based on the 12 protein-coding genes and complete mitochondrial sequence indicated that the six specimens of C. hongkongensis formed a monophyletic group and shared a sister group relationship with C. ariakensis, C. nippona, C. sikamea, C. angulata, C. gigas, and C. iredalei, whereas specimens from the Sanmen bay area clustered later with the five other C. hongkongensis individuals, sharing a sub-clade. The newly sequenced mitogenome had more singleton sites than previously published C. hongkongensis mitogenomes. CONCLUSIONS: Crassostrea hongkongensis may be a native species, and the species' range extends further to the north than previously known. Our data may therefore contribute to a better understanding of the species diversity and conservation of Crassostrea oysters.