Effects of supplemental medusa (Rhopilema esculentum) on intestinal microbiota and metabolites in silver pomfret (Pampus argenteus).

Pampus argenteus demonstrates a preference for Rhopilema esculentum as prey, yet the ramifications of consuming supplemental medusa on fish microbiota and metabolism remain elusive. To elucidate these effects, 300 juvenile fish were divided into two groups: control group (C, given commercial food only) and supplemental medusa (SM) group (given supplemental medusa + commercial feed). After 15 days, fish in the SM group exhibited a significant increase in fatness, the amylase activity in the intestine significantly increased, and the intestinal microvilli were arranged more neatly. The comprehensive approach involving 16S rRNA amplicon sequencing and metabolomics was employed, leading to the identification of five genera within the SM group, namely Lactococcus, Cohaesibacter, Maritalea, Sulfitobacter, and Carnobacterium. Functional prediction analysis of the microbiota indicated that the consumption of supplemental medusa facilitated processes such as glycolysis/gluconeogenesis and amino acid absorption. Metabolomics analysis revealed significant enrichment of 85 differential metabolites, most of them belonging to fatty acids and conjugates. These differential metabolites primarily participated in processes such as amino acid metabolism, fatty acid synthesis, and disease. Notably, the consumption of medusa resulted in a significant reduction in nine lysophospholipids associated with cardiovascular disease and inflammation. Pearson's correlation coefficient analysis revealed associations between specific microorganisms and metabolites, indicating that Cobetia, Weissella, and Macrococcus exhibited an increased abundance in the SM group, positively correlating with apocynin, 12-Hete, and delta 9-THC-d3. The indicator bacteria Psychrobacter reduced in the SM group, exhibiting a negative correlation with cystathionine (a compound involved in glutathione synthesis). Overall, the supplementation of medusa may confer a beneficial effect on the immunity of the fish. This study contributes to the theoretical framework for fish feed development.

Introduction of a Hydroxyl Self-Sacrificing Surface on Ultrathin Poly(heptazine imide) Nanosheets by KCl Grafting: A New Strategy to Improve the Photocatalytic Production of H2O2.

The generation of H2O2 through photocatalysis is increasingly recognized as a viable approach for addressing the energy and environmental challenges encountered in industrial production processes. In this research, we synthesized ultrathin (1 nm) poly(heptazine imide) (PHI) nanosheets as a photocatalyst by a one-step KCl molten salt process. The utilization of Fourier transform infrared and X-ray photoelectron spectroscopy substantiated that the interlayer-bonded potassium atoms induce polarization in water molecules, facilitating the attachment of hydroxyl groups on the surfaces of nanosheets. These groups serve as self-sacrificing entities, promoting the reaction that leads to the generation of H2O2. The preparation temperature and KCl doping amount factors for the H2O2 generation rate were investigated, and the mechanism of the KCl-bonded structure on photogeneration charge separation transport was analyzed. Owing to the elevated crystallization and the presence of surface self-sacrificing hydroxyl groups, the rate of H2O2 production reaches 6117.5 and 308.35 µmol·g-1·h-1 under visible-light irradiation (λ ≥ 420 nm) in isopropanol solution and pure water, respectively. These rates are 30 and 18.7 times higher than those observed for bulk g-C3N4, respectively. The photocatalytic kinetic processes for H2O2 formation and decomposition were also calculated to investigate the catalyst activities.

Two high quality chromosome-scale genome assemblies of female and male silver pomfret (Pampus argenteus).

Pampus argenteus is a highly commercial marine fish whose population is declining sharply. Here, we generated a female P. argenteus genome, spanning 536.33 Mb with contig N50 of 1.79 Mb; 24070 genes (99.50% of 24,182) were functionally annotated. To improve quality of it, we assembled a 553.79 Mb genome of male fish with contig N50 of 24.75 Mb through HiFi and ultra-long ONT sequence technologies; 550.82 Mb were anchored onto 24 gap-free chromosomes; 22,892 genes (98.1% of 23,346) were functionally annotated; the QV value was 51.55 with 98.9% of BUSCO and 99.39% coverage of Illumina reads. Finally, we compared this genome with previous published one, revealing 37,301 SVs. 52.82 Mb and 18.05 Mb SDs were characterized in our and published assemblies, respectively, and 48.96 Mb PURs were constructed. Thus, this genome assembly exhibits excellent completeness, continuity and accuracy comparing to the published one, which can be current preferred reference genome. Overall, these works help aquaculture and wild resources recovery of P. argenteus and provide a valuable genetic resource for study.

Clinical characteristics and outcomes of COVID-19 in pediatric patients with rheumatic diseases.

BACKGROUND: This study investigates the clinical characteristics and outcomes of pediatric patients with rheumatic diseases infected with COVID-19 in China. METHODS: We conducted a retrospective analysis of pediatric patients with rheumatic diseases who contracted COVID-19. Data were collected via a comprehensive questionnaire with a 14-day follow-up. Multivariable logistic regression was used to assess severe outcomes, and network analyses evaluated symptom correlations. RESULTS: A total of 1070 cases were collected. Fever (88.05%) and cough (62.75%) were the most common symptoms. Cough, nasal congestion, and runny nose exhibited a stronger correlation with each other. A higher incidence of fever reduced the incidence of two single symptoms (nasal congestion [r = -0.833], runny nose [r = -0.762]). Vaccinated children showed a shorter time to negative COVID-19 conversion (7.21 days vs. 7.63 days, p < 0.05) and lower hospitalization rates (p = 0.025). Prolonged symptom duration was associated with older age (OR: 1.07 [1.04-1.11]; p < 0.001) and systemic lupus erythematosus (OR: 1.47 [1.01-2.12]; p = 0.046). CONCLUSIONS: Pediatric patients with rheumatic diseases exhibited a wide range of clinical symptoms after COVID-19 infection. The infection generally did not lead to severe outcomes in this study. COVID-19 vaccination was associated with reduced hospitalization risk and expediting the time to negativity for virus. IMPACTS: This manuscript demonstrates a comprehensive analysis of the clinical characteristics and outcomes of COVID-19 infection in pediatric patients with rheumatic diseases in China. It provides critical insights into the specific challenges faced by this vulnerable population and offers practical recommendations for improving patient management during periods of increased infectious risk.

Understanding the mechanism of microplastic-associated antibiotic resistance genes in aquatic ecosystems: Insights from metagenomic analyses and machine learning.

The pervasive presence of microplastics (MPs) in aquatic systems facilitates the transmission of antibiotic resistance genes (ARGs), thereby posing risks to ecosystems and human well-being. However, owing to variations in environmental backgrounds and the limited scope of research subjects, studies on ARGs in MPs lack unified conclusions, particularly regarding whether different types of MPs selectively promote ARG enrichment. Analysing large-scale datasets can better encompass broad spatiotemporal scales and diverse samples, facilitating a more extensive exploration of the complex ecological relationships between MPs and ARGs. The present study integrated existing metagenomic datasets to conduct a comprehensive risk assessment and comparative analysis of resistance groups across various MPs. In addition, we endeavoured to elucidate potential associations between ARGs and bacterial taxa, as well as MP structural features, using machine learning (ML) methods. The findings of our research highlight the pivotal role of MP type in shaping plastispheres, accounting for 9.56 % of the biotic variation (Adonis index) and explaining 18.59 % of the ARG variance. Compared to conventional MPs, biodegradable MPs, such as polyhydroxyalkanoates (PHA) and polylactic acid (PLA), exhibit lower species uniformity and diversity but pose a higher risk of ARG occurrence. These ML approaches effectively forecasted ARG abundance by using the bacterial taxa and molecular structure descriptors (MDs) of MPs (average R2tra = 0.882, R2test = 0.759). Feature analysis showed that MDs associated with lipophilicity, solubility, toxicity, and surface potential significantly influenced the relative abundance of ARGs in the plastispheres. The interpretable multiple linear regression (MLR) model, particularly notable, elucidated a linear relationship between bacterial genera and ARGs, offering promise for identifying potential ARG hosts. This study offers novel insights into ARG dynamics and ecological risks within aquatic plastispheres, highlighting the importance of comprehensive MP monitoring initiatives.

Ginsenoside Rg2 alleviates astrocyte inflammation and ameliorates the permeability of the Alzheimer's disease related blood-brain barrier.

BACKGROUND: Damage to the blood-brain barrier (BBB) is vital for the development of Alzheimer's disease (AD). Ginsenoside Rg2 (G-Rg2) has been shown to improve a variety of brain injuries, but whether G-Rg2 can improve the BBB leakage related to AD is still unclear. PURPOSE: Illuminate the effect and mechanism of G-Rg2 on AD-related BBB damage. To clarify the role of G-Rg2 in Toll-like receptor pathway and oxidative stress pathway and its effect on tight junction proteins (TJs) expression in vivo and in vitro experiments. METHODS AND RESULTS: In our research, the tightness of the BBB was improved and the inflammatory pathway was suppressed after 4 weeks of treatment with G-Rg2 (10 mg kg-1 and 20 mg kg-1) in aluminum trichloride (AlCl3) plus d-galactose (D-gal) caused AD mice (p < 0.05; p < 0.01). Concurrently, the stability of TJs in mouse brain endothelial cells (bEnd3) was improved after okadaic acid (OA) -induced AD model cells were pretreated with G-Rg2 (5 µM, 10 µM, and 20 µM) for 24 h (p < 0.05; p < 0.01). The oxidative stress pathway and Toll-like receptor pathway in mouse astrocyte-cerebellum (MA-c) were inhibited (p < 0.05; p < 0.01). Meanwhile, in vitro interaction model results showed that G-Rg2 reduced the activation of MA-c, thereby alleviating the degradation of TJs in bEnd3 (p < 0.05; p < 0.01). The co-culture system of MA-c and bEnd3 further clearly demonstrated that G-Rg2 (20 µM) could improve their interaction and enhance BBB tightness. CONCLUSION: This study suggests that G-Rg2 can inhibit the TLR4/MyD88/MMP9 inflammatory pathway by reducing the activation of MA-c and the binding of TLR4 to MyD88, thereby decreasing the secretion of inflammatory factors and matrix metalloproteinases (MMPs), hence maintaining the stability of TJs in bEnd3, which may be one of the mechanisms of G-Rg2 in reducing AD-related BBB damage.

Unlocking lysosomal acidity to activate membranolytic module for accurately cancer theranostics.

Chemotherapy drug efflux, toxic side effects, and low efficacy against drug-resistant cells have plagued safe and efficient cancer theranostics. However, the materials or methods that resolve these defects all-in-one are scarce. Here, a new cancer theranostics strategy is proposed by utilizing changes in lysosomal acidity in cancer cells to activate the membranolytic model to overcome these obstacles together. Therefore, a simple fluorescent anthracene derivative Lyso-Mito is developed, which has a perfect pKa (4.62) value that falls between the pH of lysosomes in cancer and normal cells. Lyso-Mito itself can precisely target and convert the pH perturbation of lysosomes in cancer cells to fluorescent response and membranolytic module activity to accomplish the low drug efflux, weak toxic side effects, and low drug-resistant cancer diagnosis and treatment without linking other functional units or any additional assistance. Hereby, a new cancer theranostics strategy of integrating organelle microenvironment and the membranolytic model is realized.

Progress in systematics and biogeography of Orchidaceae.

Orchidaceae are one of the largest families of angiosperms in terms of species richness. In the last decade, numerous studies have delved into reconstructing the phylogenetic framework of Orchidaceae, leveraging data from plastid, mitochondrial and nuclear sources. These studies have provided new insights into the systematics, diversification and biogeography of Orchidaceae, establishing a robust foundation for future research. Nevertheless, pronounced controversies persist regarding the precise placement of certain lineages within these phylogenetic frameworks. To address these discrepancies and deepen our understanding of the phylogenetic structure of Orchidaceae, we provide a comprehensive overview and analysis of phylogenetic studies focusing on contentious groups within Orchidaceae since 2015, delving into discussions on the underlying reasons for observed topological conflicts. We also provide a novel phylogenetic framework at the subtribal level. Furthermore, we examine the tempo and mode underlying orchid species diversity from the perspective of historical biogeography, highlighting factors contributing to extensive speciation. Ultimately, we delineate avenues for future research aimed at enhancing our understanding of Orchidaceae phylogeny and diversity.

Physical effects of 3D microenvironments on confined cell behaviors.

Cell migration is a fundamental and functional cellular process, influenced by complex microenvironment consisting of different cells and extracellular matrix (ECM). Recent research has highlighted that, besides biochemical cues from the microenvironment, physical cues can also greatly alter cellular behavior. However, due to the complexity of the microenvironment, little is known about how the physical interactions between migrating cells and surrounding microenvironment instruct cell movement. Here, we explore various examples of 3D microenvironment reconstruction models in vitro and describe how the physical interplay between migrating cells and the neighboring microenvironment controls cell behavior. Understanding this mechanical cooperation will provide key insights into organ development, regeneration, and tumor metastasis.

Inhibitory effects of phytic acid on the in vitro and in vivo growth of Trichothecium roseum in apple fruit and the underlying mechanisms involved in its action.

This study evaluated the inhibitory impacts of phytic acid on the growth of T. roseum both in vitro and in apple fruit, as well as elucidated the potential mechanisms underlying its action. Results showed that phytic acid suppressed the lesion diameter caused by T. roseum inoculation in apples, as well as spore germination and mycelial growth of T. roseum in vitro. Phytic acid reduced intracellular conductivity and soluble sugar content, while increasing malondialdehyde and soluble protein contents. Phytic acid treatment inhibited the activities of pectin lyase, pectin methyl polygalacturonase, ß-glucosidase, cellulase, xylanase, pectin methyl trans-eliminase, polygalacturonase, and polygalacturonase both in vitro and in apples. In contrast, inoculation of control and phytic acid-treated fruit with T. roseum resulted in increased enzyme activity. These findings suggest that phytic acid decrease the occurrence of heart rot in apples through inducing disruption of the cell membrane of T. roseum and mediating cell wall metabolism.

Enhanced Nitric Oxide Delivery Through Self-Assembling Nanoparticles for Eradicating Gram-Negative Bacteria.

In the current battle against antibiotic resistance, the resilience of Gram-negative bacteria against traditional antibiotics is due not only to their protective outer membranes but also to mechanisms like efflux pumps and enzymatic degradation of drugs, underscores the urgent need for innovative antimicrobial tactics. Herein, this study presents an innovative method involving the synthesis of three furoxan derivatives engineered to self-assemble into nitric oxide (NO) donor nanoparticles (FuNPs). These FuNPs, notably supplied together with polymyxin B (PMB), achieve markedly enhanced bactericidal efficacy against a wide spectrum of bacterial phenotypes at considerably lower NO concentrations (0.1-2.8 µg mL-1), which is at least ten times lower than the reported data for NO donors (≥200 µg mL-1). The bactericidal mechanism is elucidated using confocal, scanning, and transmission electron microscopy techniques. Neutron reflectometry confirms that FuNPs initiate membrane disruption by specifically engaging with the polysaccharides on bacterial surfaces, causing structural perturbations. Subsequently, PMB binds to lipid A on the outer membrane, enhancing permeability and resulting in a synergistic bactericidal action with FuNPs. This pioneering strategy underscores the utility of self-assembly in NO delivery as a groundbreaking paradigm to circumvent traditional antibiotic resistance barriers, marking a significant leap forward in the development of next-generation antimicrobial agents.

The volumes of amygdala subregions and peripheral programmed cell death protein-1 levels are associated with cognitive decline in individuals with knee osteoarthritis.

BACKGROUND: Persistent pain is a prominent symptom of knee osteoarthritis (KOA) and has been associated with cognitive decline in individuals with KOA. The amygdala, a complex structure consisting of nine subnuclei, and programmed cell death protein-1 (PD-1) levels play crucial roles in pain regulation and cognitive processing. This study aims to investigate the relationships among amygdala subregion volumes, cognitive function, and PD-1 levels to elucidate the underlying mechanism of cognitive decline in KOA. METHODS: In this cross-sectional study, we recruited 36 patients with KOA and 25 age/gender-matched healthy controls for neuropsychological tests, structural magnetic resonance imaging scanning, and measurement of serum PD-1 levels. We used the atlas provided by FreeSurfer software to automatically segment the amygdala subnuclei. Subsequently, we compared the volumes of amygdala subregions between groups and explored their correlation with clinical scores and PD-1 levels. RESULTS: Compared to healthy controls, individuals with KOA exhibited significantly lower scores on global cognition tasks, such as long-delay free recall, short-delay free recall, and immediate recall tasks. Moreover, they displayed decreased volumes in lateral nucleus basal nucleus paralaminar nucleus while showing increased volumes in accessory basal nucleus, central nucleus, medial nucleus, and cortical nucleus. Within the KOA group specifically, paralaminar volume was negatively correlated with immediate recall scores; pain scores were negatively correlated with global cognition; basal volume was negatively correlated with PD-1 levels. CONCLUSION: Our findings highlight those alterations in amygdala subregion volumes along with changes in serum PD-1 levels may contribute to observe cognitive decline among individuals suffering from KOA.

Blunted Cardiac Mitophagy in Response to Metabolic Stress Contributes to HFpEF.

BACKGROUND: Metabolic remodeling and mitochondrial dysfunction are hallmarks of heart failure with reduced ejection fraction. However, their role in the pathogenesis of HF with preserved ejection fraction (HFpEF) is poorly understood. METHODS: In a mouse model of HFpEF, induced by high-fat diet and Nω-nitrol-arginine methyl ester, cardiac energetics was measured by 31P NMR spectroscopy and substrate oxidation profile was assessed by 13C-isotopmer analysis. Mitochondrial functions were assessed in the heart tissue and human induced pluripotent stem cell-derived cardiomyocytes. RESULTS: HFpEF hearts presented a lower phosphocreatine content and a reduced phosphocreatine/ATP ratio, similar to that in heart failure with reduced ejection fraction. Decreased respiratory function and increased reactive oxygen species production were observed in mitochondria isolated from HFpEF hearts suggesting mitochondrial dysfunction. Cardiac substrate oxidation profile showed a high dependency on fatty acid oxidation in HFpEF hearts, which is the opposite of heart failure with reduced ejection fraction but similar to that in high-fat diet hearts. However, phosphocreatine/ATP ratio and mitochondrial function were sustained in the high-fat diet hearts. We found that mitophagy was activated in the high-fat diet heart but not in HFpEF hearts despite similar extent of obesity suggesting that mitochondrial quality control response was impaired in HFpEF hearts. Using a human induced pluripotent stem cell-derived cardiomyocyte mitophagy reporter, we found that fatty acid loading stimulated mitophagy, which was obliterated by inhibiting fatty acid oxidation. Enhancing fatty acid oxidation by deleting ACC2 (acetyl-CoA carboxylase 2) in the heart stimulated mitophagy and improved HFpEF phenotypes. CONCLUSIONS: Maladaptation to metabolic stress in HFpEF hearts impairs mitochondrial quality control and contributed to the pathogenesis, which can be improved by stimulating fatty acid oxidation.

Application and innovation of artificial intelligence models in wastewater treatment.

At present, as the problem of water shortage and pollution is growing serious, it is particularly important to understand the recycling and treatment of wastewater. Artificial intelligence (AI) technology is characterized by reliable mapping of nonlinear behaviors between input and output of experimental data, and thus single/integrated AI model algorithms for predicting different pollutants or water quality parameters have become a popular method for simulating the process of wastewater treatment. Many AI models have successfully predicted the removal effects of pollutants in different wastewater treatment processes. Therefore, this paper reviews the applications of artificial intelligence technologies such as artificial neural networks (ANN), adaptive network-based fuzzy inference system (ANFIS) and support vector machine (SVM). Meanwhile, this review mainly introduces the effectiveness and limitations of artificial intelligence technology in predicting different pollutants (dyes, heavy metal ions, antibiotics, etc.) and different water quality parameters such as biochemical oxygen demand (BOD), chemical oxygen demand (COD), total nitrogen (TN) and total phosphorus (TP) in wastewater treatment process, involving single AI model and integrated AI model. Finally, the problems that need further research together with challenges ahead in the application of artificial intelligence models in the field of environment are discussed and presented.

Stochastic processes driving cyanobacterial temporal succession in response to typhoons in a coastal reservoir.

Typhoons associated with heavy rainfall events, potentially triggering harmful algal blooms (cyanoHABs) dominated by cyanobacteria in coastal reservoirs. These blooms deteriorate water quality and produce toxins, posing a threat to aquatic ecosystems. However, the ecological mechanisms driving cyanobacteria communities in response to typhoons remain unclear. To address this gap, we investigated a coastal reservoir with high-frequency sampling during two typhoon seasons. We employed comprehensive statistical methods under neutral and evolutionary theories to analyze environmental dynamics and cyanobacterial genus succession. Our findings revealed a significant increase in nutrient loads following typhoons, with concentrations of total nitrogen (TN), total phosphorus (TP), and ammonia-nitrogen (NH4+-N) rising from 0.4 mg/L to 1.0 mg/L, 0.02 mg/L to 0.63 mg/L, and 0.03 mg/L to 0.26 mg/L, respectively. These changes coincided with fluctuations in other physicochemical parameters under changing hydrometeorological conditions. Despite significant environmental disturbances, the cyanobacterial community exhibited a remarkable recovery within 15-25 days following the typhoons. This recovery progressed through four distinct successional phases, with a notable shift in community composition from Raphidiopsis and Pseudoanabaena to Aphanocapsa, subsequently replaced by Raphidiopsis and Microcystis, before reverting to the pre-typhoon community structure. During the entire successional phase, the availability of TN and the TN/TP ratio played a dominant role, as indicated by PLS-PM analysis (total effects = -0.6; p < 0.05). Pre-typhoon, environmental factors primarily influenced community structure (54 %) based on modified stochasticity ratio. However, following the typhoons, stochastic fluctuations took precedence (71 %-91 %). The rapid recovery of cyanobacterial communities and the shift in driving mechanisms from deterministic to stochastic processes underscore the complex ecological responses to typhoon events. This study provides essential insights for biodiversity preservation and ecosystem restoration, emphasizing the need to consider both stochastic and deterministic processes in ecological management strategies.

Buddleoside-rich Chrysanthemum indicum L. extract modulates macrophage-mediated inflammation to prevent metabolic syndrome induced by unhealthy diet.

BACKGROUND: Metabolic syndrome (MetS) is a precursor to the development of many diseases (atherosclerosis, diabetes, etc.). It is marked by disruptions in glucose and lipid metabolism, along with hypertension. Numerous types of risk factors contribute to the development of the MetS, inflammation and insulin resistance are present throughout the metabolic abnormalities. Chrysanthemum indicum L. is a traditional Chinese plant used for both tea and medicine, known for its high content of total flavonoids, which are important secondary metabolites. Our research led to the extraction of a Buddleoside-Rich Chrysanthemum indicum L. extract (BUDE) which has demonstrated anti-inflammatory properties. Nonetheless, the specific role and mechanism of BUDE in preventing MetS remain unclear. METHODS: The study initially evaluated the role of BUDE in preventing MetS. Subsequently, it investigated the anti-inflammatory properties of BUDE in the liver and pancreas in response to unhealthy diets. It then examined the level of insulin resistance and pancreatic ß-cell function induced by inflammation. Additionally, an lipopolysaccharide (LPS)-induced macrophage inflammation model was used to further investigate the ameliorative effects of BUDE in inflammation. RESULTS: BUDE has hypotensive, hypoglycemic and hypolipidemic effects. It can also resolve the imbalance between macrophage subpopulations, impede the triggering of the NF-κB signaling pathway, reduce the secretion of inflammatory mediators, ameliorate insulin resistance, and safeguard organs such as the liver and pancreas from inflammatory damage. These effects collectively contribute to preventing the development of MetS. DISCUSSION: BUDE has the ability to modulate macrophage-mediated inflammation, leading to improved insulin resistance. Additionally, it delivers antihypertensive, hypoglycemic, and hypolipidemic effects, offering a potential for preventing MetS.

Fibroblast growth factor 8 promotes in vitro neurite outgrowth of placode-derived petrosal and nodose ganglia to varying degrees.

Fibroblast growth factors (FGFs) are required for the specification and formation of the epibranchial placodes, which give rise to the distal part of the cranial sensory ganglia. However, it remains unclear whether FGFs play a role in regulating the neurite outgrowth of the epibranchial placode-derived ganglia during further development. Previous studies have shown that Fibroblast growth factor 8 (FGF8) promotes neurite outgrowth from the statoacoustic ganglion in vitro. However, these studies did not distinguish between the neural crest- and placode-derived components of the sensory ganglia. In this study, we focused on the petrosal and nodose ganglia as representatives of the epibranchial ganglia and investigated their axonal outgrowth under the influence of FGF8 signaling protein in vitro. To precisely isolate the placode-derived ganglion part, we labeled the placode and its derivatives with enhanced green fluorescent protein (EGFP) through electroporation. The isolated ganglia were then collected for qRT-PCR assay and cultured in a collagen gel with and without FGF8 protein. Our findings revealed that both placode-derived petrosal and nodose ganglia expressed FGFR1 and FGFR2. In culture, FGF8 exerted a neural trophic effect on the axon outgrowth of both ganglia. While the expression levels of FGFR1/2 were similar between the two ganglia, the petrosal ganglion exhibited greater sensitivity to FGF8 compared to the nodose ganglion. This indicates that the placode-derived ganglia have differential responsiveness to FGF8 signaling during axonal extension. Thus, FGF8 is not only required for the early development of the epibranchial placode, as shown in previous studies, but also promotes neurite outgrowth of placode-derived ganglia.

Substrate access tunnel engineering of a Fe-type nitrile hydratase from Pseudomonas fluorescens ZJUT001 for substrate preference adjustment and catalytic performance enhancement.

Substrate access tunnel engineering is a useful strategy for enzyme modification. In this study, we improved the catalytic performance of Fe-type Nitrile hydratase (Fe-type NHase) from Pseudomonas fluorescens ZJUT001 (PfNHase) by mutating residue Q86 at the entrance of the substrate access tunnel. The catalytic activity of the mutant PfNHase-αQ86W towards benzonitrile, 2-cyanopyridine, 3-cyanopyridine, and 4-hydroxybenzonitrile was enhanced by 9.35-, 3.30-, 6.55-, and 2.71-fold, respectively, compared to that of the wild-type PfNHase (PfNHase-WT). In addition, the mutant PfNHase-αQ86W showed a catalytic efficiency (kcat/Km) towards benzonitrile 17.32-fold higher than the PfNHase-WT. Interestingly, the substrate preference of PfNHase-αQ86W shifted from aliphatic nitriles to aromatic nitrile substrates. Our analysis delved into the structural changes that led to this altered substrate preference, highlighting an expanded entrance tunnel region, theenlarged substrate-binding pocket, and the increased hydrophobic interactions between the substrate and enzyme. Molecular dynamic simulations and dynamic cross-correlation Matrix (DCCM) further supported these findings, providing a comprehensive explanation for the enhanced catalytic activity towards aromatic nitrile substrates.

Identification, molecular profiling and immune functions of cystatin M in silver pomfret (Pampus argenteus).

Cystatins play an important role in various physiological and pathological processes of organisms, including regulating protein metabolism, antigen processing, inflammatory response, nutritional disorders, and controlling enzyme activity. However, research on immunity functions of fish cystatin M is limited. In this study, Pampus argenteus cystatin M (Pacystatin M) was identified and analyzed. Its amino acid sequence was highly conserved in teleosts, and included the conserved cystatin cysteine protease inhibitor motifs. Pacystatin M was highly expressed in the gill, spleen, and intestine, whereas the expression levels of liver and kidney were lower. Furthermore, Nocardia seriolae infection up-regulated the expression of Pacystatin M in the kidney, spleen and liver, with particularly significant expression observed in the liver on day 15 post-infection. Functional analysis indicated that the recombinant Pacystatin M showed increasing inhibitory activity against papain within a certain concentration range, suggesting that the inhibition was likely competitive. Additionally, Pacystatin M demonstrated the ability to inhibit bacterial growth and high thermal stability. These results suggested that Pacystatin M might be involved in the immune response to microbial invasion and provided new reference addressing disease issues in the large-scale farming of silver pomfret.