Study of obesity research using machine learning methods: A bibliometric and visualization analysis from 2004 to 2023.

BACKGROUND: Obesity, a multifactorial and complex health condition, has emerged as a significant global public health concern. Integrating machine learning techniques into obesity research offers great promise as an interdisciplinary field, particularly in the screening, diagnosis, and analysis of obesity. Nevertheless, the publications on using machine learning methods in obesity research have not been systematically evaluated. Hence, this study aimed to quantitatively examine, visualize, and analyze the publications concerning the use of machine learning methods in obesity research by means of bibliometrics. METHODS: The Web of Science core collection was the primary database source for this study, which collected publications on obesity research using machine learning methods over the last 20 years from January 1, 2004, to December 31, 2023. Only articles and reviews that fit the criteria were selected for bibliometric analysis, and in terms of language, only English was accepted. VOSviewer, CiteSpace, and Excel were the primary software utilized. RESULTS: Between 2004 and 2023, the number of publications on obesity research using machine learning methods increased exponentially. Eventually, 3286 publications that met the eligibility criteria were searched. According to the collaborative network analysis, the United States has the greatest volume of publications, indicating a significant influence on this research. coauthor's analysis showed the authoritative one in this field is Leo Breiman. Scientific Reports is the most widely published journal. The most referenced publication is "R: a language and environment for statistical computing." An analysis of keywords shows that deep learning, support vector machines, predictive models, gut microbiota, energy expenditure, and genome are hot topics in this field. Future research directions may include the relationship between obesity and its consequences, such as diabetic retinopathy, as well as the interaction between obesity and epidemiology, such as COVID-19. CONCLUSION: Utilizing bibliometrics as a research tool and methodology, this study, for the first time, reveals the intrinsic relationship and developmental pattern among obesity research using machine learning methods, which provides academic references for clinicians and researchers in understanding the hotspots and cutting-edge issues as well as the developmental trend in this field to detect patients' obesity problems early and develop personalized treatment plans.

Characterization of a multiresistance optrA- and lsa(E)-harbouring unconventional circularizable structure in Streptococcus suis.

OBJECTIVES: To identify novel genetic elements facilitating the horizontal transfer of the oxazolidinone/phenicol resistance gene optrA and the pleuromutilin-lincosamide-streptogramin A resistance gene lsa(E) in Streptococcus suis. METHODS: The complete genomes of S. suis HB18 and two transconjugants were obtained using both the Illumina and Nanopore platforms. MICs were determined by broth microdilution. Inverse PCR was performed to identify circular forms of the novel unconventional circularizable structure (UCS), genomic island (GI) and integrative and conjugative element (ICE). Conjugation experiments assessed the transferability of optrA and lsa(E) genes in S. suis. RESULTS: S. suis HB18 carried a multiresistance gene cluster optrA-lsa(E)-lnu(B)-aphA-aadE-spw. This gene cluster, flanked by intact and truncated erm(B) in the same orientation, resided on a novel ICESsuHB18. Inverse PCR revealed the existence of a novel UCS, named UCS-optrA + lsa(E), which could excise the gene cluster optrA-lsa(E)-lnu(B)-aphA-aadE-spw and one copy of erm(B) from ICESsuHB18. Two transconjugants with different characteristics were obtained. In transconjugant T-JH-GI, UCS-optrA + lsa(E) excised from ICESsuHB18 inserted into the erm(B)-positive GI, designated GISsuHB18, generating the novel GISsuHB18-1. Meanwhile, in T-JH-ICE, genetic rearrangement events occurred in ICESsuHB18 and GISsuHB18, forming the novel ICESsuHB18-1. CONCLUSIONS: This is the first report demonstrating the functionally active UCS-optrA + lsa(E) excising from ICESsuHB18 and inserting into the erm(B)-positive GISsuHB18 during the conjugation process. The location of optrA and lsa(E) on a multiresistance UCS enhances its persistence and dissemination.

Genomic insight into the diversity of Glaesserella parasuis isolates from 19 countries.

Glaesserella parasuis is a commensal bacterial organism found in the upper respiratory tract of healthy pigs and the etiological agent of Glässer's disease, which causes severe economic losses in the swine industry. This study aimed to better understand the epidemiological characteristics of this opportunistic pathogen. We investigated the prevalence and distribution of sequence types (STs), serovars, antimicrobial resistance genes (ARGs), and potential virulence factors (VFs) in 764 G. parasuis isolates collected from diseased and healthy pigs from 19 countries, including China. Multilocus sequence typing showed a high degree of variation with 334 STs, of which 93 were not previously recognized. Phylogenetic analysis revealed two major clades distinguished by isolation year, source, country, and serovar. The dominant serovars of G. parasuis were serovars 4 (19.50%), 7 (15.97%), 5/12 (13.87%), and 13 (12.30%). Serovar 7 gradually became one of the dominant serovars in G. parasuis with more VFs and fewer ARGs. Serovars 4 and 5/12 were the most frequent serovars in diseased pigs, whereas serovars 2, 8, and 11 were predominant in healthy pigs. Serovars 7 and 13 possessed more VFs than the other serovars. This study provides novel insights into the global prevalence and epidemiology of G. parasuis and valuable clues for further investigation into the pathogenicity of G. parasuis, which will facilitate the development of effective vaccines.IMPORTANCEGlaesserella parasuis is a clinically important gram-negative opportunistic pathogen, which causes serious financial losses in swine industry on a global scale. No vaccine is known that provides cross-protection against all 15 serovars; furthermore, the correlation between serovar and virulence is largely unknown. This study provides a large number of sequenced strains in 19 countries and compares the genomic diversity of G. parasuis between diseased and healthy pigs. We found a slight change in the dominant serovar of G. parasuis in the world, with serovar 7 gradually emerging as one of the predominant serovars. The observed higher average number of VFs in this particular serovar strain challenges the previously held notion that serovar 7 is non-virulent, indicating a more complex virulence landscape than previously understood. Our analysis indicating that six ARGs [tet(B), sul2, aph(3')-Ia, aph (6)-Id, blaROB-1, and aph(3'')-Ib] are likely to be transmitted horizontally in their entirety. By analyzing VFs, we provided an improved understanding of the virulence of G. parasuis, and these key findings suggest that vaccine development will be challenging.

Salmonella Typhimurium alters galactitol metabolism under ciprofloxacin treatment to balance resistance and virulence.

Ciprofloxacin-resistant Salmonella Typhimurium (S. Typhimurium) causes a significant health burden worldwide. A wealth of studies has been published on the contributions of different mechanisms to ciprofloxacin resistance in Salmonella spp. But we still lack a deep understanding of the physiological responses and genetic changes that underlie ciprofloxacin exposure. This study aims to know how phenotypic and genotypic characteristics are impacted by ciprofloxacin exposure, from ciprofloxacin-susceptible to ciprofloxacin-resistant strains in vitro. Here, we investigated the multistep evolution of resistance in replicate populations of S. Typhimurium during 24 days of continuously increasing ciprofloxacin exposure and assessed how ciprofloxacin impacts physiology and genetics. Numerous studies have demonstrated that RamA is a global transcriptional regulator that prominently perturbs the transcriptional landscape of S. Typhimurium, resulting in a ciprofloxacin-resistant phenotype appearing first; the quinolone resistance-determining region mutation site can only be detected later. Comparing the microbial physiological changes and RNA sequencing (RNA-Seq) results of ancestral and selectable mutant strains, the selectable mutant strains had some fitness costs, such as decreased virulence, an increase of biofilm-forming ability, a change of "collateral" sensitivity to other drugs, and inability to utilize galactitol. Importantly, in the ciprofloxacin induced, RamA directly binds and activates the gatR gene responsible for the utilization of galactitol, but RamA deletion strains could not activate gatR. The elevated levels of RamA, which inhibit the galactitol metabolic pathway through the activation of gatR, can lead to a reduction in the growth rate, adhesion, and colonization resistance of S. Typhimurium. This finding is supported by studies conducted in M9 medium as well as in vivo infection models. IMPORTANCE: Treatment of antibiotic resistance can significantly benefit from a deeper understanding of the interactions between drugs and genetics. The physiological responses and genetic mechanisms in antibiotic-exposed bacteria are not well understood. Traditional resistance studies, often retrospective, fail to capture the entire resistance development process and typically exhibit unpredictable dynamics. To explore how clinical isolates of S. Typhimurium respond to ciprofloxacin, we analyzed their adaptive responses. We found that S. Typhimurium RamA-mediated regulation disrupts microbial metabolism under ciprofloxacin exposure, affecting genes in the galactitol metabolic pathways. This disruption facilitates adaptive responses to drug therapy and enhances the efficiency of intracellular survival. A more comprehensive and integrated understanding of these physiological and genetic changes is crucial for improving treatment outcomes.

Rapid Identification of Brucella Genus and Species In Silico and On-Site Using Novel Probes with CRISPR/Cas12a.

Human brucellosis caused by Brucella is a widespread zoonosis that is prevalent in many countries globally. The high homology between members of the Brucella genus and Ochrobactrum spp. often complicates the determination of disease etiology in patients. The efficient and reliable identification and distinction of Brucella are of primary interest for both medical surveillance and outbreak purposes. A large amount of genomic data for the Brucella genus was analyzed to uncover novel probes containing single-nucleotide polymorphisms (SNPs). GAMOSCE v1.0 software was developed based on the above novel eProbes. In conjunction with clinical requirements, an RPA-Cas12a detection method was developed for the on-site determination of B. abortus and B. melitensis by fluorescence and lateral flow dipsticks (LFDs). We demonstrated the potential of these probes for rapid and accurate detection of the Brucella genus and five significant Brucella species in silico using GAMOSCE. GAMOSCE was validated on different Brucella datasets and correctly identified all Brucella strains, demonstrating a strong discrimination ability. The RPA-Cas12a detection method showed good performance in detection in clinical blood samples and veterinary isolates. We provide both in silico and on-site methods that are convenient and reliable for use in local hospitals and public health programs for the detection of brucellosis.

Stroke risk of COPD patients and death risk of COPD patients following a stroke: A systematic review and meta-analysis.

OBJECTIVE: Chronic obstructive pulmonary disease (COPD) is closely related to the development and progression of cardiovascular disease. The purpose of this study is to clarify the answers to the following questions through systematic evaluation: the risk of stroke in COPD patients; the risk of stroke in acute exacerbations of COPD (AECOPD) patients; and the risk of death after stroke in COPD patients. METHODS: Two reviewers independently searched EMbase, PubMed, and the Cochrane Library for relevant literature from the date of creation to February 17, 2023, for studies relating COPD to stroke patients. Of the 8039 publications retrieved, we identified 27 articles that met our selection criteria. Fixed-effects or random-effects models were used to calculate ORs and 95% confidence intervals for the combined risk. RESULTS: combining studies on stroke risk in COPD patients by random-effects model suggested that COPD was an independent risk factor for stroke-associated pneumonia (OR 1.40, 95% CI: 1.24-1.59, I2 = 98.4%, P = .000), with significant heterogeneity in the results, and subgroup analysis did not find a source of heterogeneity. In the combined 7 AECOPD studies, a significantly higher risk of stroke was found (OR 1.53, 95% CI: 1.44-1.63, I2 = 49.2%, P = .066). In the combined 6 short- term prognostic studies, the relationship between COPD and risk of death was not highly significant (OR 1.12, 95% CI: 1.08-1.16, I2 = 37.4%, P = .131). In 10 long-term observational prognosis studies, COPD was suggested to be associated with death after stroke by combining data using a random-effects model (OR 1.20, 95% CI: 1.13-1.27, I2 = 56.8%, P = .014), and there was moderate heterogeneity in the combination, with subgroup analysis showing that stroke type may be a source of heterogeneity and the risk of death from ischemic stroke: OR 1.23, 95% CI: 1.17-1.29, I2 = 45.0%, P = .191 and the risk of death from both types of stroke: OR 1.12, 95% CI: 1.07-1.18, I2 =18.9%, P = .291. CONCLUSION: COPD is an independent risk factor for stroke. The risk of stroke is significantly increased, especially during AECOPD. In addition, the association between COPD and short-term death in stroke patients is insignificant, while it is more associated with fatal events in the long-term prognosis.

Association between diabetes and venous thromboembolism: A systematic review and meta-analysis.

BACKGROUND: Diabetes mellitus (DM) plays a vital role in the development of cardiovascular disease. However, its association with venous thromboembolism (VTE) remains unclear, for the published study results are conflicting. We performed a meta-analysis of published cohort studies and case-control studies to assess the role of DM in the formation and prognosis of VTE. METHODS: PubMed and EMBASE databases were searched for articles from the database's establishment until September 15, 2022. Of the 15,754 publications retrieved, 50 studies were identified that met the selection criteria. The New castle-Ottawa Scale was used to evaluate the quality of the literature. Pooled odds ratios (ORs) and 95% confidence intervals were calculated using fixed- or random-effect models. RESULTS: We combined OR using a random-effects or fixed-effects model: patients with DM had an increased risk of VTE (OR 1.27, 95% confidence interval [CI]: 1.15-1.41), which still showed a partial association in studies adjusted by confounding factors (OR 1.20, 95% CI: 1.07-1.35). DM was not significantly associated with VTE when analyzed in studies adjusted by body mass index (OR 1.04, 95% CI: 0.94-1.15). VTE patients with DM had a higher risk of short-term and long-term mortality than those without DM (OR 1.58 [95% CI: 1.26-1.99] for long-term mortality and OR 1.20 [95% CI: 1.19-1.21] for short-term mortality). CONCLUSION: There was no significant association between DM and VTE risk, and body mass index may be a significant confounding factor between DM and VTE risk. However, DM can still lead to an increased risk of long-term and short-term mortality in patients with VTE.

Potential Therapeutic Options for Premature Ovarian Insufficiency: Experimental and Clinical Evidence.

Premature ovarian insufficiency (POI) is a condition in which a woman experiences premature decline in ovarian function before the age of 40 years, manifested by menstrual disorders, decreased fertility, and possibly postmenopausal symptoms such as insomnia, hot flashes, and osteoporosis, and is one of the predominant clinical syndromes leading to female infertility. Genetic, immunologic, iatrogenic and other factors, alone or in combination, have been reported to trigger POI, yet the etiology remains unknown in most cases. The main methods currently used clinically to ameliorate menopausal symptoms due to hypoestrogenemia in POI patients are hormone replacement therapy, while the primary methods available to address infertility in POI patients are oocyte donation and cryopreservation techniques, both of which have limitations to some degree. In recent years, researchers have continued to explore more efficient and safe therapies, and have achieved impressive results in preclinical trials. In this article, we will mainly review the three most popular therapies and their related signaling pathways published in the past ten years, with the aim of providing ideas for clinical applications.

DNA double-strand break genetic variants in patients with premature ovarian insufficiency.

Premature ovarian insufficiency (POI) is a clinically heterogeneous disease that may seriously affect the physical and mental health of women of reproductive age. POI primarily manifests as ovarian function decline and endocrine disorders in women prior to age 40 and is an established cause of female infertility. It is crucial to elucidate the causative factors of POI, not only to expand the understanding of ovarian physiology, but also to provide genetic counselling and fertility guidance to affected patients. Factors leading to POI are multifaceted with genetic factors accounting for 7% to 30%. In recent years, an increasing number of DNA damage-repair-related genes have been linked with the occurrence of POI. Among them, DNA double-strand breaks (DSBs), one of the most damaging to DNA, and its main repair methods including homologous recombination (HR) and non-homologous end joining (NHEJ) are of particular interest. Numerous genes are known to be involved in the regulation of programmed DSB formation and damage repair. The abnormal expression of several genes have been shown to trigger defects in the overall repair pathway and induce POI and other diseases. This review summarises the DSB-related genes that may contribute to the development of POI and their potential regulatory mechanisms, which will help to further establish role of DSB in the pathogenesis of POI and provide theoretical guidance for the study of the pathogenesis and clinical treatment of this disease.

Prevalence, Risk Factor and Clinical Characteristics of Venous Thrombus Embolism in Patients with Acute Exacerbation of COPD: A Prospective Multicenter Study.

Background and Objective: The prevalence of venous thrombus embolism (VTE) in patients with chronic obstructive pulmonary disease (COPD) is higher than in patients without COPD. Owing to the similarity of clinical symptoms between PE and acute exacerbation COPD (AECOPD), PE is likely to be overlooked or underdiagnosed in patients with AECOPD. The aim of the study was to investigate the prevalence, risk factor, clinical characteristics, and prognostic impact of VTE in patients with AECOPD. Methods: This multicenter, prospective, cohort study was conducted in 11 research centers of China. Data on the baseline characteristics, VTE-related risk factors, clinical symptoms, laboratory examination results, computed tomography pulmonary angiography (CTPA) and lower limb venous ultrasound of AECOPD patients were collected. Patients were followed up for 1 year. Results: A total of 1580 AECOPD patients were included in the study. The mean (SD) age was 70.4 (9.9) years and 195 (26%) patients were women. The prevalence of VTE was 24.5% (387/1580) and PE was 16.8% (266/1580). VTE patients were older; had higher BMI; and longer course of COPD than non-VTE patients. The history of VTE, cor pulmonale, less purulent sputum, increased respiratory rate, higher D-dimer, and higher NT-proBNP/BNP were independently associated with VTE in hospitalized patients with AECOPD. The mortality at 1-year was higher in patients with VTE than patients without VTE (12.9% vs 4.5%, p<0.01). There was no significant difference in the prognosis of patients with PE in segmental or subsegmental arteries and in main pulmonary arteries or lobar arteries (P>0.05). Conclusion: VTE is common in COPD patients and is associated with poor prognosis. Patients with PE at different locations had poorer prognosis than patients without PE. It is necessary to perform active screening strategy for VTE in AECOPD patients with risk factors.

Functional Characterization of a Novel SMR-Type Efflux Pump RanQ, Mediating Quaternary Ammonium Compound Resistance in Riemerella anatipestifer.

Riemerella anatipestifer (R. anatipestifer) is a multidrug-resistant bacterium and an important pathogen responsible for major economic losses in the duck industry. Our previous study revealed that the efflux pump is an important resistance mechanism of R. anatipestifer. Bioinformatics analysis indicated that the GE296_RS02355 gene (denoted here as RanQ), a putative small multidrug resistance (SMR)-type efflux pump, is highly conserved in R. anatipestifer strains and important for the multidrug resistance. In the present study, we characterized the GE296_RS02355 gene in R. anatipestifer strain LZ-01. First, the deletion strain RA-LZ01ΔGE296_RS02355 and complemented strain RA-LZ01cΔGE296_RS02355 were constructed. When compared with that of the wild-type (WT) strain RA-LZ01, the mutant strain ΔRanQ showed no significant influence on bacterial growth, virulence, invasion and adhesion, morphology biofilm formation ability, and glucose metabolism. In addition, the ΔRanQ mutant strain did not alter the drug resistance phenotype of the WT strain RA-LZ01 and displayed enhanced sensitivity toward structurally related quaternary ammonium compounds, such as benzalkonium chloride and methyl viologen, which show high efflux specificity and selectivity. This study may help elucidate the unprecedented biological functions of the SMR-type efflux pump in R. anatipestifer. Thus, if this determinant is horizontally transferred, it could cause the spread of quaternary ammonium compound resistance among bacterial species.

Multisite assessment of reproducibility in high-content cell migration imaging data.

High-content image-based cell phenotyping provides fundamental insights into a broad variety of life science disciplines. Striving for accurate conclusions and meaningful impact demands high reproducibility standards, with particular relevance for high-quality open-access data sharing and meta-analysis. However, the sources and degree of biological and technical variability, and thus the reproducibility and usefulness of meta-analysis of results from live-cell microscopy, have not been systematically investigated. Here, using high-content data describing features of cell migration and morphology, we determine the sources of variability across different scales, including between laboratories, persons, experiments, technical repeats, cells, and time points. Significant technical variability occurred between laboratories and, to lesser extent, between persons, providing low value to direct meta-analysis on the data from different laboratories. However, batch effect removal markedly improved the possibility to combine image-based datasets of perturbation experiments. Thus, reproducible quantitative high-content cell image analysis of perturbation effects and meta-analysis depend on standardized procedures combined with batch correction.

EptA of Riemerella anatipestifer mediates phenotypes involved in colistin resistance and virulence.

Colistin (polymyxin E) is a group of cationic antimicrobial cyclic peptides and is recognized as a last-resort defense against lethal infections with carbapenem-resistant pathogens. In addition to the plasmid-borne mobilized phosphoethanolamine (PEA) transferases, the functional expression of lipid A-modifying enzymes encoded on chromosomes has been attributed to intrinsic bacterial colistin resistance. However, the mechanisms of colistin resistance in Riemerella anatipestifer remain unknown. Herein, the GE296_RS09715 gene-encoded Lipid A PEA transferases (RaEptA) was identified in R. anatipestifer. Genetic and structural analyses revealed that the amino acid sequence of RaEptA shared 26.6%-33.1% similarities with the family of Lipid A PEA transferases (EptA) and MCR-like proteins and have defined 12 residues that contribute to the formation of phosphatidylethanolamine (PE)-recognizable cavities. Comparative analyses of colistin resistance in RA-LZ01 and RA-LZ01ΔRaEptA showed the level of colistin has fallen from 96 µg mL-1 down to 24 ~ 32 µg mL-1 . Site-directed mutagenesis assay of the PE-binding cavity and expression of the mutants reveals that K309-rRaEptA can remodel the surface of Escherichia coli and rendering it resistant to colistin, suggesting this point-mutation of P309K is necessary for EptA-mediated lipid A modification. Moreover, the virulence of RA-LZ01ΔRaEptA was attenuated compared with RA-LZ01 both in vivo and vitro. Taken together, the results represent the RaEptA involved in the colistin resistance and pathogenicity, and the P309K mutation might alter bacterial adaptation and increase the spread of colistin resistance from R. anatipestifer to other gram-negative bacteria. The findings of this study suggest another scenario for the spread of colistin resistance genes and should be considered by a wide audience.

SMURF1 inhibits the Th17 and Th17.1 polarization and improves the Treg/Th17 imbalance in systemic lupus erythematosus through the ubiquitination of RORγt.

Systemic lupus erythematosus (SLE) is a systemic autoimmune disease. This study aimed to investigate the role of SMAD specific E3 ubiquitin protein ligase 1 (SMURF1) in the Th17 and Th17.1 differentiation and Treg/Th17 imbalance, which are major factors contributing to the pathogenesis of SLE. SLE patients and healthy individuals were recruited to detect the SMURF1 levels in naïve CD4+ cells from peripheral blood. Purified and expanded naïve CD4+ T cells were employed to evaluate the effects of SMURF1 on Th17 and Th17.1 polarization in vitro. MRL/lpr lupus model was employed to explore the disease phenotype as well as Treg/Th17 balance in vivo. The results showed that SMURF1 was down-regulated in naïve CD4+ T cells in peripheral blood of patients with SLE and in spleen of MRL/lpr mice. SMURF1 overexpression suppressed the polarization of naïve CD4+ T cells toward Th17 and Th17.1 phenotype and down-regulated the expression of retinoid-related orphan receptor-gammat (RORγt). Subsequently, SMURF1 down-regulation aggravated the disease phenotype, inflammation, and the Treg/Th17 imbalance in MRL/lpr mice. Furthermore, we found that SMURF overexpression promoted the ubiquitination and decreases the stability of RORγt. In conclusion, SMURF1 inhibited the polarization of Th17 and Th17.1 cells and improved the Treg/Th17 imbalance in SLE, which was mediated as least partly by the ubiquitination of RORγt.

OmpA is involved in the invasion of duck brain microvascular endothelial cells by Riemerella anatipestifer.

Bacterial meningitis is a major cause of morbidity and mortality. Despite advances in antimicrobial chemotherapy, the disease remains detrimental to humans, livestock, and poultry. Riemerella anatipestifer is a gram-negative bacterium causing duckling serositis and meningitis. However, the virulence factors contributing to its binding and invasion of duck brain microvascular endothelial cells (DBMECs) and penetration of the blood-brain barrier (BBB) have never been reported. In this study, immortalized DBMECs were successfully generated and used as an in vitro-model of duck BBB. Furthermore, ompA gene deletion mutant of the pathogen and multiple complemented strains carrying the complete ompA gene and its truncated forms were constructed. Bacterial growth, invasion, and adhesion assays and animal experiments were performed. The results show that the OmpA protein of R. anatipestifer had no effect on bacterial growth and adhesion ability to DBMECs. The role of OmpA in the invasion of R. anatipestifer into DBMECs and duckling BBB was confirmed. The amino acids 230-242 of OmpA represents a key domain involved in R. anatipestifer invasion. In addition, another OmpA1164 protein constituted by the amino acids 102-488 within OmpA could function as a complete OmpA. The signal peptide sequence from amino acids 1-21 had no significant effect on OmpA functions. In conclusion, this study illustrated that OmpA is an important virulence factor mediating R. anatipestifer invasion of DBMECs and penetration of the duckling BBB.

Remarkably enhanced thermal properties of tobacco granules with high-thermal-conductivity nanoparticles.

Heated tobacco products (HTPs) are a novel type of cigarette that have received extensive attention. The tobacco plug could be made from tobacco granules (TGs), which are heated but not burned during the inhalation process. Thermal conductivity is an important property to evaluate the speed of heating TGs to meet the critical temperature for generating aerosol. Nevertheless, thermal physics properties of TGs is rarely reported. In this study, the thermophysical performance for the tobacco granules is systematically studied. An effective strategy of raising the thermal conductivity of TGs by introducing a small amount of nanoparticles of high-thermal-conductivity-materials (HTCMs, copper, silver, and graphene) is proposed, which not only results in a 35% improvement in the thermal conductivity but also reduces the maximum temperature for generating aerosol. In addition, introducing Cu and Ag particles in the TGs are favorable for improving the antibacterial effect. This method is worth promoting for enhancing the thermal conductivity of other plant-derived heated products.

Antimicrobial Resistance Surveillance of Tigecycline-Resistant Strains Isolated from Herbivores in Northwest China.

There is no doubt that antimicrobial resistance (AMR) is a global threat to public health and safety, regardless of whether it's caused by people or natural transmission. This study aimed to investigate the genetic characteristics and variations of tigecycline-resistant Gram-negative isolates from herbivores in northwest China. In this study, a total of 300 samples were collected from various provinces in northwest China, and 11 strains (3.67%) of tigecycline-resistant bacteria were obtained. In addition, bacterial identification and antibiotic susceptibility testing against 14 antibiotics were performed. All isolates were multiple drug-resistant (MDR) and resistant to more than three kinds of antibiotics. Using an Illumina MiSeq platform, 11 tigecycline-resistant isolates were sequenced using whole genome sequencing (WGS). The assembled draft genomes were annotated, and then sequences were blasted against the AMR gene database and virulence factor database. Several resistance genes mediating drug resistance were detected by WGS, including fluoroquinolone resistance genes (gyrA_S83L, gyrA_D87N, S83L, parC_S80I, and gyrB_S463A), fosfomycin resistance genes (GlpT_E448K and UhpT_E350Q), beta-lactam resistance genes (FtsI_D350N and S357N), and the tigecycline resistance gene (tetR N/A). Furthermore, there were five kinds of chromosomally encoded genetic systems that confer MDR (MarR_Y137H, G103S, MarR_N/A, SoxR_N/A, SoxS_N/A, AcrR N/A, and MexZ_K127E). A comprehensive analysis of MDR strains derived from WGS was used to detect variable antimicrobial resistance genes and their precise mechanisms of resistance. In addition, we found a novel ST type of Escherichia coli (ST13667) and a newly discovered point mutation (K127E) in the MexZ gene of Pseudomonas aeruginosa. WGS plays a crucial role in AMR control, prevention strategies, as well as multifaceted intervention strategies.

Construction of Prognostic Risk Model for Small Cell Lung Cancer Based on Immune-Related Genes.

Small cell lung cancer (SCLC) is a highly invasive and fatal malignancy. Research at the present stage implied that the expression of immune-related genes is associated with the prognosis in SCLC. Accordingly, it is essential to explore effective immune-related molecular markers to judge prognosis and treat SCLC. Our research obtained SCLC dataset from Gene Expression Omnibus (GEO) and subjected mRNAs in it to differential expression analysis. Differentially expressed mRNAs (DEmRNAs) were intersected with immune-related genes to yield immune-related differentially expressed genes (DEGs). The functions of these DEGs were revealed by Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment analyses. Thereafter, we categorized 3 subtypes of immune-related DEGs via K-means clustering. Kaplan-Meier curves analyzed the effects of 3 subtypes on SCLC patients' survival. Single-sample gene set enrichment analysis (ssGSEA) and ESTIMATE validated that the activation of different immune gene subtypes differed significantly. Finally, an immune-related-7-gene assessment model was constructed by univariate-Lasso-multiple Cox regression analyses. Riskscores, Kaplan-Meier curves, receiver operating characteristic (ROC) curves, and independent prognostic analyses validated the prognostic value of the immune-related-7-gene assessment model. As suggested by GSEA, there was a prominent difference in cytokine-related pathways between high- and low-risk groups. As the analysis went further, we discovered a statistically significant difference in the expression of human leukocyte antigen (HLA) proteins and costimulatory molecules expressed on the surface of CD274, CD152, and T lymphocytes in different groups. In a word, we started with immune-related genes to construct the prognostic model for SCLC, which could effectively evaluate the clinical outcomes and offer guidance for the treatment and prognosis of SCLC patients.

Characteristics of a new carotenoid cleavage dioxygenase NtCCD10 derived from Nicotiana tabacum.

MAIN CONCLUSION: A new carotenoid cleavage dioxygenase NtCCD10 from tobacco was characterized. There is some difference between NtCCD10 and CCD1 in structure. NtCCD10 can cleave the C5-C6 (C5'-C6') and C9-C10 (C9'-C10') double bonds of carotenoids and has high catalytic activity. Carotenoid cleavage dioxygenases (CCDs) cleave carotenoids to produce a variety of apocarotenoids, which have important biological functions for organisms in nature. There are eleven CCDs subfamilies in the plant kingdom, many of which have been extensively characterized in their functions. However, as a newly classified subfamily, the function of CCD10 has rarely been studied. In this work, the function of an NtCCD10 gene from dicotyledonous Nicotiana tabacum was cloned and characterized, and its phylogeny, molecular structural modeling and protein structure were also systematically analyzed. Like other CCDs, NtCCD10 also possesses a seven bladed ß-propeller with Fe2+ cofactor in its center constituting the active site of the enzyme. The Fe2+ is also coordinated bonding with four conserved histidine residues. Meanwhile, NtCCD10 also has many unique features, such as its α1 and α3 helixes are not anti-parallel, a special ß-sheet and a longer access tunnel for substrates. When expressed in engineered Escherichia coli (producing phytoene, lycopene, ß-carotene, and zeaxanthin) and Saccharomyces cerevisiae (producing ß-carotene), NtCCD10 could symmetrically cleave phytoene and ß-carotene at the C9-C10 and C9'-C10' positions to produce geranylacetone and ß-ionone, respectively. In addition, NtCCD10 could also cleave the C5-C6 and C5'-C6' double bonds of lycopene to generate 6-methyl-5-heptene-2-one (MHO). NtCCD10 has higher catalytic activity than PhCCD1 in yeast, which provides a good candidate CCD for biosynthesis of ß-ionone and has potential applications in biotechnological industry. This study identified the taxonomic position and catalytic activity of the first NtCCD10 in dicotyledonous plants. This will provide a reference for the discovery and functional identification of CCD10 enzymes in dicotyledons.

Characteristics of NtCCD1-3 from tobacco, and protein engineering of the CCD1 to enhance ß -ionone production in yeast.

Biosynthesis of ß-ionone by microbial cell factories has become a promising way to obtain natural ß-ionone. The catalytic activity of carotenoid cleavage dioxygenase 1 (CCD1) in cleavage of ß-carotene to ß-ionone severely limits its biosynthesis. In this study, NtCCD1-3 from Nicotiana tabacum with high ability to cleave ß-carotene was screened. Multiple strategies for improving the ß-ionone yield in Saccharomyces cerevisiae were performed. The results showed that NtCCD1-3 could cleave a variety of caroteniods at the 9,10 (9',10') double bonds and lycopene at the 5,6 (5',6') positions. The insertion site delta for NtCCD1-3 gene was more suitable for enhancing the yield of ß-ionone, showing 19.1-fold increase compared with the rox1 site. More importantly, mutant K38A of NtCCD1-3 in membrane-bonding domains could greatly promote ß-ionone production by more than 3-fold. We also found that overexpression of the NADH kinase Pos5 could improve ß-ionone yield up to 1.5 times. These results may provide valuable references for biosynthesis of ß-ionone.