Evaluation of [18F]fluoroestradiol and ChRERα as a gene expression PET reporter system in rhesus monkey brain.

Positron emission tomography (PET) reporter systems are a valuable means of estimating the level of expression of a transgene in vivo. For example, the safety and efficacy of gene therapy approaches for the treatment of neurological and neuropsychiatric disorders could be enhanced via the monitoring of exogenous gene expression levels in the brain. The present study evaluated the ability of a newly developed PET reporter system [18F]fluoroestradiol ([18F]FES) and the estrogen receptor-based PET reporter ChRERα, to monitor expression levels of a small hairpin RNA (shRNA) designed to suppress choline acetyltransferase (ChAT) expression in rhesus monkey brain. The ChRERα gene and shRNA were expressed from the same transcript via lentivirus injected into monkey striatum. In two monkeys that received injections of viral vector, [18F]FES binding increased by 70% and 86% at the target sites compared with pre-injection, demonstrating that ChRERα expression could be visualized in vivo with PET imaging. Post-mortem immunohistochemistry confirmed that ChAT expression was significantly suppressed in regions in which [18F]FES uptake was increased. The consistency between PET imaging and immunohistochemical results suggests that [18F]FES and ChRERα can serve as a PET reporter system in rhesus monkey brain for in vivo evaluation of the expression of potential therapeutic agents, such as shRNAs.

N, O-Doped Walnut-Like Porous Carbon Composite Microspheres Loaded with Fe/Co Nanoparticles for Adjustable Electromagnetic Wave Absorption.

This study addresses the challenge of designing simple and environmentally friendly methods for the preparation of effective electromagnetic wave (EMW) absorbing materials with tailored microstructures and multi-component regulation. N, O doped walnut-like porous carbon composite microspheres loaded with FeCo nanoparticles (WPCM/Fe-Co) are synthesized through high-temperature carbonization combined with soap-free emulsion polymerization and hydrothermal methods, avoiding the use of toxic solvents and complex conditions. The incorporation of magnetic components enhances magnetic loss, complementing dielectric loss to optimize EMW attenuation. The unique walnut-like morphology further improves impedance matching. The proportions of Fe and Co components can be adjusted to regulate the material's reflection loss, thickness, and bandwidth, allowing for fine-tuning of absorption performance. At a low filling ratio (16.7%), the optimal WPCM/Fe-Co composites exhibit a minimum reflection loss (RLmin) of -48.34 dB (10.33 GHz, 3.0 mm) and an overall effective absorbing bandwidth (EAB) covering the entire C bands, X bands, and Ku bands. This work introduces a novel approach to composition regulation and presents a green synthesis method for magnetic carbon composite absorbers with high-performance EMW absorption at low loading.

Cell factory design with advanced metabolic modelling empowered by artificial intelligence.

Advances in synthetic biology and artificial intelligence (AI) have provided new opportunities for modern biotechnology. High-performance cell factories, the backbone of industrial biotechnology, are ultimately responsible for determining whether a bio-based product succeeds or fails in the fierce competition with petroleum-based products. To date, one of the greatest challenges in synthetic biology is the creation of high-performance cell factories in a consistent and efficient manner. As so-called white-box models, numerous metabolic network models have been developed and used in computational strain design. Moreover, great progress has been made in AI-powered strain engineering in recent years. Both approaches have advantages and disadvantages. Therefore, the deep integration of AI with metabolic models is crucial for the construction of superior cell factories with higher titres, yields and production rates. The detailed applications of the latest advanced metabolic models and AI in computational strain design are summarized in this review. Additionally, approaches for the deep integration of AI and metabolic models are discussed. It is anticipated that advanced mechanistic metabolic models powered by AI will pave the way for the efficient construction of powerful industrial chassis strains in the coming years.

Evaluation of immunoregulation and immunoprotective efficacy of Glaesserella parasuis histidine kinase QseC.

QseC is a membrane sensor kinase that enables bacteria to perceive autoinducers -3, adrenaline, and norepinephrine to initiate downstream gene transcription. In this study, we found that the QseC protein of Glaesserella parasuis can serve as an effective antigen to activate the host's immune response. Therefore, we investigated the immunogenicity and host protective effect of this protein. ELISA and indirect immunofluorescence results showed that QseC protein can induce high titer levels of humoral immunity in mice and regularly generate specific serum antibodies. We used MTS reagents to detect lymphocyte proliferation levels and found that QseC protein can cause splenic lymphocyte proliferation with memory and specificity. Further immunological analysis of the spleen cell supernatant revealed significant upregulation of levels of IL-1ß, IL-4 and IFN-γ in the QseC + adjuvant group. In the mouse challenge experiment, it was found that QseC + adjuvant can provide effective protection. The results of this study demonstrate that QseC protein provides effective protection in a mouse model and has the potential to serve as a candidate antigen for a novel subunit vaccine for further research.

In vivo evaluation of a novel 18F-labeled PET radioligand for translocator protein 18 kDa (TSPO) in monkey brain.

PURPOSE: [18F]SF51 was previously found to have high binding affinity and selectivity for 18 kDa translocator protein (TSPO) in mouse brain. This study sought to assess the ability of [18F]SF51 to quantify TSPO in rhesus monkey brain. METHODS: Positron emission tomography (PET) imaging was performed in monkey brain (n = 3) at baseline and after pre-blockade with the TSPO ligands PK11195 and PBR28. TSPO binding was calculated as total distribution volume corrected for free parent fraction in plasma (VT/fP) using a two-tissue compartment model. Receptor occupancy and nondisplaceable uptake were determined via Lassen plot. Binding potential (BPND) was calculated as the ratio of specific binding to nondisplaceable uptake. Time stability of VT was used as an indirect probe to detect radiometabolite accumulation in the brain. In vivo and ex vivo experiments were performed in mice to determine the distribution of the radioligand. RESULTS: After [18F]SF51 injection, the concentration of brain radioactivity peaked at 2.0 standardized uptake value (SUV) at ~ 10 min and declined to 30% of the peak at 180 min. VT/fP at baseline was generally high (203 ± 15 mL· cm-3) and decreased by ~ 90% after blockade with PK11195. BPND of the whole brain was 7.6 ± 4.3. VT values reached levels similar to terminal 180-min values by 100 min and remained relatively stable thereafter with excellent identifiability (standard errors < 5%), suggesting that no significant radiometabolites accumulated in the brain. Ex vivo experiments in mouse brain showed that 96% of radioactivity was parent. No significant uptake was observed in the skull, suggesting a lack of defluorination in vivo. CONCLUSION: The results demonstrate that [18F]SF51 is an excellent radioligand that can quantify TSPO with a good ratio of specific to nondisplaceable uptake and has minimal radiometabolite accumulation in brain. Collectively, the results suggest that [18F]SF51 warrants further evaluation in humans.

Sensitivity analysis and adaptive mutation strategy differential evolution algorithm for optimizing enzymes' turnover numbers in metabolic models.

Genome-scale metabolic network model (GSMM) based on enzyme constraints greatly improves general metabolic models. The turnover number ( k cat ${k}_{\mathrm{cat}}$ ) of enzymes is used as a parameter to limit the reaction when extending GSMM. Therefore, turnover number plays a crucial role in the prediction accuracy of cell metabolism. In this work, we proposed an enzyme-constrained GSMM parameter optimization method. First, sensitivity analysis of the parameters was carried out to select the parameters with the greatest influence on predicting the specific growth rate. Then, differential evolution (DE) algorithm with adaptive mutation strategy was adopted to optimize the parameters. This algorithm can dynamically select five different mutation strategies. Finally, the specific growth rate prediction, flux variability, and phase plane of the optimized model were analyzed to further evaluate the model. The enzyme-constrained GSMM of Saccharomyces cerevisiae, ecYeast8.3.4, was optimized. Results of the sensitivity analysis showed that the optimization variables can be divided into three groups based on sensitivity: most sensitive (149 k cat ${k}_{\mathrm{cat}}$ c), highly sensitive (1759 k cat ${k}_{\mathrm{cat}}$ ), and nonsensitive (2502 k cat ${k}_{\mathrm{cat}}$ ) groups. Six optimization strategies were developed based on the results of the sensitivity analysis. The results showed that the DE with adaptive mutation strategy can indeed improve the model by optimizing highly sensitive parameters. Retaining all parameters and optimizing the highly sensitive parameters are the recommended optimization strategy.

Multiple feature fusion transformer for modeling penicillin fermentation process with unequal sampling intervals.

The quality prediction of batch processes is an important task in the field of biological fermentation. However, dynamic nonlinearity, unequal sampling intervals, uneven duration, and multiple features of a batch process make this task challenging. Thus, the multiple-feature fusion transformer (MFFT) model is proposed for the time series quality prediction of a batch process. First, the application of sequence-to-sequence architecture enables MFFT to perform a wide range of sequence prediction tasks. Second, the transformer parallel operation model imposes no rigid requirement for the order of sequence input, allowing the model to deal with problems of unequal interval sampling and utilize the sequence information. Third, MFFT integrates a pretrained ResNet50 as a mycelium status classifier for fusing image information into the features. Moreover, a multiple-feature encoding structure is proposed to integrate sampling time and mycelium status. Finally, multiple tasks in penicillin fermentation have shown that MFFT significantly outperforms existing methods for time series prediction.

Dynamic analysis of rumor propagation model with media report and time delay on social networks.

When a rumor appears on social networks, the media of relevant departments need reaction time to make an authoritative announcement. Considering the effects of the media report and time delay on a rumor spreading, and the different attitudes of individuals towards media reports. We proposed a susceptible-expose-infective-media-remover (SEIMR) rumor propagation model with media reports and time delay. Firstly, the basic reproduction number of the model is obtained. Secondly, the positivity, boundedness and existence of the solutions of the model are analyzed. Then, the local asymptotic stability of the rumor free equilibrium and the boundary equilibriums is proved, and the global asymptotic stability of the equilibriums is proved by constructing Lyapunov function when the time delay is zero. Besides, the prevention and control effects of the media report on rumor spreading and the effect of time delay are analyzed. The shorter time delay in media report and the greater the impact of the media report, the more effective the suppression of rumors will be. Finally, the accuracy of the theoretical results as well as the effects of different parameters of the model have been verified through numerical simulations, and the effectiveness of the SEIMR model has been verified via comparative experiments.

Comprehensive analysis of transcriptome and metabolome analysis reveal new targets of Glaesserella parasuis glucose-specific enzyme IIBC (PtsG).

The ptsG (hpIIBCGlc) gene, belonging to the glucose-specific phosphotransferase system, encodes the bacterial glucose-specific enzyme IIBC. In this study, the effects of a deletion of the ptsG gene were investigated by metabolome and transcriptome analyses. At the transcriptional level, we identified 970 differentially expressed genes between ΔptsG and sc1401 (Padj<0.05) and 2072 co-expressed genes. Among these genes, those involved in methane metabolism, amino sugar and nucleotide sugar metabolism, starch and sucrose metabolism, pyruvate metabolism, phosphotransferase system (PTS), biotin metabolism, Two-component system and Terpenoid backbone biosynthesis showed significant changes in the ΔptsG mutant strain. Metabolome analysis revealed that a total of 310 metabolites were identified, including 20 different metabolites (p < 0.05). Among them, 15 metabolites were upregulated and 5 were downregulated in ΔptsG mutant strain. Statistical analysis revealed there were 115 individual metabolites having correlation, of which 89 were positive and 26 negative. These metabolites include amino acids, phosphates, amines, esters, nucleotides, benzoic acid and adenosine, among which amino acids and phosphate metabolites dominate. However, not all of these changes were attributable to changes in mRNA levels and must also be caused by post-transcriptional regulatory processes. The knowledge gained from this lays the foundation for further study on the role of ptsG in the pathogenic process of Glaesserella parasuis (G.parasuis).

Genome-Scale Metabolic Model's multi-objective solving algorithm based on the inflexion point of Pareto front including maximum energy utilization and its application in Aspergillus niger DS03043.

The solution of Genome-Scale Metabolic Model (GSMM) directly affects the simulation accuracy of the metabolic process in digital cells. Single-objective optimization methods, such as flux balance analysis (FBA), which is widely used in solving GSMM, have limitations when simulating actual biological processes, which leads to unrealistic results due to other biological constraints being ignored. A novel multi-objective differential evolution algorithm based on general FBA (i.e., differential evolution FBA [DEFBA]) is hence proposed to solve GSMM. First, in accordance with the assumption that cells minimize resource consumption and maximize resource utilization, the maximum specific growth rate and the minimum cellular production rate of ATP, NADPH, and NADH are defined as the multi-objective functions of DEFBA. Second, FBA is used to produce the initial individuals of DEFBA by changing the upper bound of biomass reaction in GSMM. Third, mutation and selection operations help in generating new individuals in the solution space to search the Pareto front. Finally, the optimal solution is selected by analyzing the inflexion point of the Pareto front. In DEFBA, multi-objective technology and optimal solution judging technology can introduce the biological constraints into the GSMM solving method, such that the solution can be more consistent with the essential biological mechanism. DEFBA is applied to solve Aspergillus niger's GSMM. The improved results show that DEFBA can be an effective general solving algorithm for GSMM.

Comparative transcriptome analysis reveals that deletion of CheY influences gene expressions of ABC transports and metabolism in Haemophilus parasuis.

Haemophilus (Glaesserella) parasuis is a commensal bacterium that causes Glässer's disease (GD) in swine. As a global transcriptional factor, CheY regulates the expression of hundreds of genes in H. parasuis. In this study, we measured changes in gene expression at the whole transcriptome level using RNAseq. We identified 2058 co-expressed genes, and found 624 differentially expressed genes (q < 0.05) in ΔcheY and SC1401. Several important GO annotations and signaling pathways were identified. RNA-seq results were assembled according to the reference genome, compared with the annotated gene model, and 12 new transcriptional regions were found. Finally, q-PCR results validated the RNA-seq results with 8 randomly selected genes. The present study indicated that CheY is mainly involved in the regulation of ABC transport, oxidative phosphorylation, and ß-Lactam resistance. We draw the regulatory network of CheY, which offers greater insight into the regulatory mechanism of CheY in H.parasuis.

Improving Tumor-to-Background Contrast through Hydrophilic Tetrazines: The Construction of 18 F-Labeled PET Agents Targeting Nonsmall Cell Lung Carcinoma.

Bioorthogonal reactions have been widely used in the biomedical field. 18 F-TCO/Tetrazine ligation is the most reactive radiolabelled inverse electron demand Diels-Alder reaction, but its application had been limited due to modest contrast ratios of the resulting conjugates. Herein, we describe the use of hydrophilic tetrazines to improve tumor-to-background contrast of neurotensin receptor targeted PET agents. PET agents were constructed using a rapid Diels-Alder reaction of the radiolabeled trans-cyclooctene (18 F-sTCO) with neurotensin (NT) conjugates of a 3,6-diaryltetrazine, 3-methyl-6-aryltetrazine, and a derivative of 3,6-di(2-hydroxyethyl)tetrazine. Although cell binding assays demonstrated all agents have comparable binding affinity, the conjugate derived from 3,6-di(2-hydroxyethyl)tetrazine demonstrated the highest tumor to muscle contrast, followed by conjugates of the 3-methyl-6-aryltetrazine and 3,6-diaryltetrazine.

Bacterial Signatures of "Red-Operculum" Disease in the Gut of Crucian Carp (Carassius auratus).

Fish gut microbiota play important roles in fish immunity, nutrition, and the adaptation to environmental changes. To date, few studies have focused on the interactions among environmental factors, fish diseases, and gut microbiota compositions. We compared the gut bacterial communities of healthy crucian carps (Carassius auratus) with those of individuals affected by "red-operculum" disease and corresponding water and sediment microbiota in four fish farm ponds. Distinct gut bacterial communities were observed in healthy and diseased fish. The bacterial communities of diseased fish were less diverse and stable than those of healthy individuals. The differences in bacterial community compositions between diseased and healthy fish were explained by the changes in the relative abundances of some specific bacterial OTUs, which belonged to the genera such as Vibrio, Aeromonas, and Shewanella, and they were prevalent in diseased fish, but rare or even absent in environmental samples. Water temperature and ammonia concentration were the two most important environmental factors that impacted gut microbiota in diseased fish. These results highlighted the surge of some potential pathogens as bacterial signatures that were associated with "red-operculum" disease in crucian carps.

Different substrate regimes determine transcriptional profiles and gene co-expression in Methanosarcina barkeri (DSM 800).

Methanosarcina barkeri (DSM 800) is a metabolically versatile methanogen and shows distinct metabolic status under different substrate regimes. However, the mechanisms underlying distinct transcriptional profiles under different substrate regimes remain elusive. In this study, based on transcriptional analysis, the growth performances and gene expressions of M. barkeri fed on acetate, H2 + CO2, and methanol, respectively, were investigated. M. barkeri showed higher growth performances under methanol, followed by H2 + CO2 and acetate, which corresponded well with the variations of gene expressions. The α diversity (evenness) of gene expressions was highest under the acetate regime, followed by H2 + CO2 and methanol, and significantly and negatively correlated with growth performances. The gene co-expression analysis showed that "Energy production and conversion," "Coenzyme transport and metabolism," and "Translation, ribosomal structure, and biogenesis" showed deterministic cooperation patterns of intra- and inter-functional classes. However, "Posttranslational modification, protein turnover, chaperones" showed exclusion with other functional classes. The gene expressions and especially the relationships among them potentially drove the shifts of metabolic status under different substrate regimes. Consequently, this study revealed the diversity-related ecological strategies that a high α diversity probably provided more fitness and tolerance under natural environments and oppositely a low α diversity strengthened some specific physiological functions, as well as the co-responses of gene expressions to different substrate regimes.

Novel Method for Radiolabeling and Dimerizing Thiolated Peptides Using (18)F-Hexafluorobenzene.

Hexafluorobenzene (HFB) reacts with free thiols to produce a unique and selective perfluoroaromatic linkage between two sulfurs. We modified this chemical reaction to produce dimeric (18)F-RGD-tetrafluorobenzene (TFB)-RGD, an integrin αvß3 receptor ligand. (18)F-HFB was prepared by a fluorine exchange reaction using K(18)F/K2.2.2 at room temperature. The automated radiofluorination was optimized to minimize the amount of HFB precursor and, thus, maximize the specific activity. (18)F-HFB was isolated by distillation and subsequently reacted with thiolated c(RGDfk) peptide under basic and reducing conditions. The resulting (18)F-RGD-TFB-RGD demonstrated integrin receptor specific binding, cellular uptake, and in vivo tumor accumulation.(18)F-HFB can be efficiently incorporated into thiol-containing peptides at room temperature to provide novel imaging agents.

Identification of Sex Chromosomes by Means of Comparative Genomic Hybridization in a Lizard, Eremias multiocellata.

Eremias multiocellata is a viviparous lizard that is known to exhibit temperature-dependent sex determination (TSD). Conventional Giemsa staining under light microscope examination has identified the karyotype of this species to be 2 n=36 I+2 m, with no detectable heteromorphic sex chromosomes. However, a highly differentiated female-specific chromosome, W, which is homomorphic with the Z chromosome, is found in the present study by the high-resolution cytogenetic method of comparative genomic hybridization (CGH). The results show that E. multiocellata is a viviparous lizard with both TSD and ZW heterogametic sex chromosomes. Despite the fact that a different sex ratio of male offspring was found in two populations (separated by an altitude of 1400 m) in previous incubation experiments, we demonstrate, using genomic in situ hybridization (GISH), that there is no significant chromosomal loss or acquisition between the two populations. This suggests that temperature may play a more important role in lowland populations. These results most likely indicate that E. multiocellata is transitioning between the evolutionary processes of TSD and genotypic sex determination (GSD) systems, and also give clues to the effect of TSD versus GSD in this process.

Triphase interface synthesis of plasmonic gold bellflowers as near-infrared light mediated acoustic and thermal theranostics.

We present a novel gold bellflower (GBF) platform with multiple-branched petals, prepared by a liquid-liquid-gas triphase interface system, for photoacoustic imaging (PAI)-guided photothermal therapy (PTT). Upon near-infrared (NIR) laser irradiation, the GBFs, with strong NIR absorption, showed very strong PA response and an ultrahigh photothermal conversion efficiency (η, ∼74%) among the reported photothermal conversion agents. The excellent performance in PAI and PTT is mainly attributed to the unique features of the GBFs: (i) multiple-branched petals with an enhanced local electromagnetic field, (ii) long narrow gaps between adjacent petals that induce a strong plasmonic coupling effect, and (iii) a bell-shaped nanostructure that can effectively amplify the acoustic signals during the acoustic propagation. Besides the notable PTT and an excellent PAI effect, the NIR-absorbing GBFs may also find applications in NIR light-triggered drug delivery, catalysis, surface enhanced Raman scattering, stealth, antireflection, IR sensors, telecommunications, and the like.

Comparative proteomic analysis of the membrane proteins of two Haemophilus parasuis strains to identify proteins that may help in habitat adaptation and pathogenesis.

BACKGROUND: Haemophilus parasuis is the causative agent of Glässer's disease characterized by polyserositis, arthritis, and meningitis in pig, leading to serious economic loss. Despite many years of study, virulence factors and the mechanisms of the entire infection process remain largely unclear. So two-dimensional gel electrophoresis and mass spectrometry were used to search for distinctions at the membrane protein expression level between two H. parasuis isolates aimed at uncovering some proteins potentially involved in habitat adaption and pathogenesis. RESULTS: A comparative proteomic approach combining two-dimensional gel electrophoresis with mass spectrometry and tandem mass spectrometry was employed to explore the differences among membrane proteomes of a virulent Haemophilus parasuis strain isolated from the lung of a diseased pig and an avirulent strain isolated from the nasal swab of a healthy pig. Differentially expressed protein spots identified by mass spectrometry were annotated and analyzed by bioinformatic interpretation. The mRNA level was determined by quantitative real-time PCR. Proteins representing diverse functional activities were identified. Among them, the tonB-dependent siderophore receptor was a new discovery highlighted for its activity in iron uptake. In addition, periplasmic serine protease and putrescine/spermidine ABC transporter substrate-binding protein were given focus because of their virulence potential. This study revealed that the differentially expressed proteins were important in either the habitat adaption or pathogenesis of H. parasuis. CONCLUSIONS: The outcome demonstrated the presence of some proteins which raise the speculation for their importance in helping in habitat adaption or pathogenesis within the host.

One-pot two-step radiosynthesis of a new (18)F-labeled thiol reactive prosthetic group and its conjugate for insulinoma imaging.

N-(2-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)ethyl)-6-fluoronicotinamide ([(18)F]FNEM), a novel prosthetic agent that is thiol-specific, was synthesized using a one-pot two-step strategy: (1) (18)F incorporation by a nucleophilic displacement of trimethylammonium substrate under mild conditions; (2) amidation of the resulting 6-[(18)F]fluoronicotinic acid 2,3,5,6-tetrafluorophenyl ester with N-(2-aminoethyl)maleimide trifluoroacetate salt. The radiosynthesis of the maleimide tracer was completed in 75 min from [(18)F]fluoride with 26 ± 5% decay uncorrected radiochemical yield, and specific activity of 19-88 GBq/µmol (decay uncorrected). The in vitro cell uptake, in vivo biodistribution, and positron emission tomography (PET) imaging properties of its conjugation product with [Cys(40)]-exendin-4 were described. [(18)F]FNEM-Cys(40)-exendin-4 showed specific targeting of glucagon-like peptide 1 receptor (GLP-1R) positive insulinomas and comparable imaging results to our recently reported [(18)F]FPenM-Cys(40)-exendin-4.

Biomimetic RNA-silencing nanocomplexes: overcoming multidrug resistance in cancer cells.

RNA interference (RNAi) is an RNA-dependent gene silencing approach controlled by an RNA-induced silencing complex (RISC). Herein, we present a synthetic RISC-mimic nanocomplex, which can actively cleave its target RNA in a sequence-specific manner. With high enzymatic stability and efficient self-delivery to target cells, the designed nanocomplex can selectively and potently induce gene silencing without cytokine activation. These nanocomplexes, which target multidrug resistance, are not only able to bypass the P-glycoprotein (Pgp) transporter, due to their nano-size effect, but also effectively suppress Pgp expression, thus resulting in successful restoration of drug sensitivity of OVCAR8/ADR cells to Pgp-transportable cytotoxic agents. This nanocomplex approach has the potential for both functional genomics and cancer therapy.