Expression Pattern of ALOXE3 in Mouse Brain Suggests Its Relationship with Seizure Susceptibility.

Arachidonic acid (AA), a polyunsaturated fatty acid, is involved in the modulation of neuronal excitability in the brain. Arachidonate lipoxygenase 3 (ALOXE3), a critical enzyme in the AA metabolic pathway, catalyzes the derivate of AA into hepoxilins. However, the expression pattern of ALOXE3 and its role in the brain has not been described until now. Here we showed that the levels of Aloxe3 mRNA and protein kept increasing since birth and reached the highest level at postnatal day 30 in the mouse hippocampus and temporal cortex. Histomorphological analyses indicated that ALOXE3 was enriched in adult hippocampus, somatosensory cortex and striatum. The distribution was restricted to the neurites of function-specific subregions, such as mossy fibre connecting hilus and CA3 neurons, termini of Schaffer collateral projections, and the layers III and IV of somatosensory cortex. The spatiotemporal expression pattern of ALOXE3 suggests its potential role in the modulation of neural excitability and seizure susceptibility. In fact, decreased expression of ALOXE3 and elevated concentration of AA in the hippocampus was found after status epilepticus (SE) induced by pilocarpine. Local overexpression of ALOXE3 via adeno-associated virus gene transfer restored the elevated AA level induced by SE, alleviated seizure severities by increasing the latencies to myclonic switch, clonic convulsions and tonic hindlimb extensions, and decreased the mortality rate in the pilocarpine-induced SE model. These results suggest that the expression of ALOXE3 is a crucial regulator of AA metabolism in brain, and potentially acts as a regulator of neural excitability, thereby controlling brain development and seizure susceptibility.

Valproate-Induced Epigenetic Upregulation of Hypothalamic Fto Expression Potentially Linked with Weight Gain.

Valproate (VPA), a widely-used antiepileptic drug, is a selective inhibitor of histone deacetylase (HDAC) that play important roles in epigenetic regulation. The patient with different diseases receiving this drug tend to exhibit weight gain and abnormal metabolic phenotypes, but the underlying mechanisms remain largely unknown. Here we show that VPA increases the Fto mRNA and protein expression in mouse hypothalamic GT1-7 cells. Interestingly, VPA promotes histone H3/H4 acetylation and the FTO expression which could be reversed by C646, an inhibitor for histone acetyltransferase. Furthermore, VPA weakens the FTO's binding and enhances the binding of transcription factor TAF1 to the Fto promoter, and C646 leads to reverse effect of the VPA, suggesting an involvement of the dynamic of histone H3/H4 acetylation in the regulation of FTO expression. In addition, the mice exhibit an increase in the food intake and body weight at the beginning of 2-week treatment with VPA. Simultaneously, in the hypothalamus of the VPA-treated mice, the FTO expression is upregulated and the H3/H4 acetylation is increased; further the FTO's binding to the Fto promoter is decreased and the TAF1's binding to the promoter is enhanced, suggesting that VPA promotes the assembly of the basal transcriptional machinery of the Fto gene. Finally, the inhibitor C646 could restore the effects of VPA on FTO expression, H3/H4 acetylation, body weight, and food intake; and loss of FTO could reverse the VPA-induced increase of body weight and food intake. Taken together, this study suggests an involvement of VPA in the epigenetic upregulation of hypothalamic FTO expression that is potentially associated with the VPA-induced weight gain.

Transmission and evolution of OXA-48-producing Klebsiella pneumoniae ST11 in a single hospital in Taiwan.

OBJECTIVES: Epidemic spread of OXA-48-producing Klebsiella pneumoniae, mainly mediated by the transmission of a blaOXA-48-carrying plasmid, has threatened global health during the last decade. Since its introduction to Taiwan in 2013, OXA-48 has become the second most common carbapenemase. We described the transmission and evolution of an OXA-producing K. pneumoniae clone in a single hospital. METHODS: Twenty-two OXA-48 K. pneumoniae were isolated between October 2013 and December 2015. Comparative genomic analysis was performed based on the WGS data generated with Illumina and MinION techniques. RESULTS: Seventeen of the 22 OXA-48 K. pneumoniae that belonged to ST11, with the same capsular genotype, KL64, and differed from each other by seven or fewer SNPs, were considered outbreak strains. Eight of the 17 outbreak strains harboured a 65499 bp blaOXA-48-carrying IncL plasmid (called pOXA48). pOXA48 was absent from the remaining nine strains. Instead, a 24.9 kb blaOXA-48-carrying plasmid fragment was integrated into a prophage region of their chromosomes. Transmission routes of the ST11_KL64 K. pneumoniae sublineages, which carried either pOXA48 or chromosomally integrated blaOXA-48, were reconstructed. CONCLUSIONS: Clonal expansion of ST11_KL64 sublineages contributed to the nosocomial outbreak of OXA-48 K. pneumoniae. The chromosome-borne blaOXA-48 lineage emerged during a 2 year period in a single hospital. Dissemination of OXA-48, which is vertically transmitted in K. pneumoniae even in the absence of selective pressure from antimicrobials, deserves public health attention.

Cadmium and arsenic accumulation during the rice growth period under in situ remediation.

Rice (Oryza sativa L.) planted in cadmium (Cd)- and arsenic (As)-contaminated soil is considered the main source of dietary Cd and As intake for humans in Southeast Asia and thereby poses a threat to human health. Minimizing the transfer of these pollutants to rice grain is an urgent task for environmental researchers. The main objective of this study was to investigate the effects and the mechanisms of a combined amendment (hydroxyapatite + zeolite + biochar, HZB) on decreasing Cd and As accumulation in rice. In situ remediation and aqueous solution adsorption experiments were conducted. The results showed that after application of HZB, Cd and As concentrations of the exchangeable fraction and TCLP extraction in soil decreased with the growth of rice plants. Cd concentrations in rice tissues were decreased at the tillering, filling and maturing stages after in situ remediation, while As concentrations in rice tissues were decreased only at the maturing stage. When 8 kg·plot-1 (9000 kg ha-1) HZB was applied, concentrations of Cd and inorganic As in brown rice were decreased to 0.18 and 0.16 mg kg-1, respectively, lower than the levels permissible for grain in China, i.e., 0.2 mg kg-1. Application of HZB reduced Cd accumulation in rice tissues, and the suppression of Cd accumulation was significantly greater than that of As. Furthermore, HZB significantly increased rice grain yield. An aqueous solution adsorption experiment demonstrated that HZB could adsorb and covalently bind Cd and As (V) via -OH, -COOH, -Si-O-Si and CO32- groups to produce carboxylates, silicates and carbonates, thereby promoting in situ immobilization of Cd and As in soil solution.

MDH2 is an RNA binding protein involved in downregulation of sodium channel Scn1a expression under seizure condition.

Voltage-gated sodium channel α-subunit type I (NaV1.1, encoded by SCN1A gene) plays a critical role in the excitability of brain. Downregulation of SCN1A expression is associated with epilepsy, a common neurological disorder characterized by recurrent seizures. Here we reveal a novel role of malate dehydrogenase 2 (MDH2) in the posttranscriptional regulation of SCN1A expression under seizure condition. We identified that MDH2 was an RNA binding protein that could bind two of the four conserved regions in the 3' UTRs of SCN1A. We further showed that knockdown of MDH2 or inactivation of MDH2 activity in HEK-293 cells increased the reporter gene expression through the 3' UTR of SCN1A, and MDH2 overexpression decreased gene expression by affecting mRNA stability. In the hippocampus of seizure mice, the upregulation of MDH2 expression contributed to the decrease of the NaV1.1 levels at posttranscriptional level. In addition, we showed that the H2O2 levels increased in the hippocampus of the seizure mice, and H2O2 could promote the binding of MDH2 to the binding sites of Scn1a gene, whereas ß-mercaptoethanol decreased the binding capability, indicating an important effect of the seizure-induced oxidation on the MDH2-mediated downregulation of Scn1a expression. Taken together, these data suggest that MDH2, functioning as an RNA-binding protein, is involved in the posttranscriptional downregulation of SCN1A expression under seizure condition.

Damxungmacin A and B, Two New Amicoumacins with Rare Heterocyclic Cores Isolated from Bacillus subtilis XZ-7.

Two new amicoumacins, named Damxungmacin A (1) and B (2), were isolated from the culture broth of a soil-derived bacterium Bacillus subtilis XZ-7. Their chemical structures were elucidated by spectroscopic studies (UV, IR, NMR and HR-ESI-MS). Compound 1 possessed a 1,4-diazabicyclo[2.2.1]heptane-2-one ring system in its structure, which was reported for the first time, while 2 had a 1-acetylmorpholine-3-one moiety, which was naturally rare. Compound 1 exhibited moderate to weak cytotoxic activities against three human tumor cell lines (A549, HCT116 and HepG2) with IC50 values of 13.33, 14.34 and 13.64 µM, respectively. Meanwhile, compound 1 showed weak antibacterial activities against some strains of Staphylococcus epidermidis, while compound 2 at 16 µg/mL did not show antibacterial activity.

The Clinical Features and Prognosis of Gastric Remnant Carcinoma after Treatment.

BACKGROUND/AIMS: The incidence of gastric remnant carcinoma does not decrease after partial gastrectomy The aim of this study was to evaluate the clinical features and prognosis of gastric remnant carcinoma after treatment. METHODOLOGY: Among 412 gastric carcinoma patients who were admitted to our hospital 21 were found to have gastric remnant carcinoma. We analyzed their clinicopathological features and prognosis. RESULTS: Prognosis did not differ significantly in terms of gender, age, tumor-lymph node-metastasis stage, tumor location, and time interval between first and subsequent operations. However, it was influenced by intensive curative gastrectomy with or without resection of local lymph nodes. CONCLUSION: Long-term follow-up after gastrectomy, appropriate curative resection, as well as prevention and management of hypertensive disease co-mobility are important to improve survival rate of gastric remnant carcinoma operation.

Hydrogen sulfide attenuates depression-like behaviours in Parkinson's disease model rats by improving synaptic plasticity in a hippocampal Warburg effect-dependent manner.

BACKGROUND: Depression is a highly prevalent comorbidity arising in patients with Parkinson's disease (PD). However, depression in patients with PD is poorly treated. Hydrogen sulfide (H2S), a neuromodulator, has the potential to relieve depression. OBJECTIVE: To investigate whether H2S attenuates depression-like behaviours in a rat model of PD and examine the underlying mechanisms. METHODS: We utilised rotenone to develop a PD model with subcutaneous injections in the dorsal cervical region of Sprague-Dawley rats. The depression-like behaviours in the rotenone-induced PD model rats were assessed through forced swimming, tail suspension, open field, novelty-suppressed feeding, and elevated plus-maze tests. The expression of postsynaptic density protein-95 and synapsin-1, related to synaptic plasticity, was detected using Western blot in the hippocampus. The hippocampal ultrastructure, including the synaptic density, length of the synaptic active zone, postsynaptic density thickness, and synaptic gap width, was detected using transmission electron microscopy. RESULTS: We proved that sodium hydrosulfide (NaHS; a donor of H2S) significantly attenuated the depression-like behaviours and disorders of hippocampal synaptic plasticity in rotenone-induced PD rats. Furthermore, inhibition of the hippocampal Warburg effect by 2-deoxyglucose abolished NaHS-enhanced hippocampal synaptic plasticity and reversed NaHS-attenuated depression-like behaviours in the rotenone-induced PD rats. CONCLUSION: H2S attenuates PD-associated depression by improving the hippocampal synaptic plasticity in a hippocampal Warburg effect-dependent manner.

Donepezil combined with traditional Chinese medicine has promising efficacy on mild cognitive impairment: a systematic review and meta-analysis.

Objective: Prior research has shown mixed results regarding the effectiveness of combining donepezil and traditional Chinese medicine (TCM) to treat mild cognitive impairment (MCI). In light of this, our study aims to examine the efficacy and safety of this treatment approach for patients with MCI. Methods: We conducted a comprehensive search of various databases, including Medline (via PubMed), Cochrane, Embase, Web of Science, Chinese National Knowledge Infrastructure, Chinese Biomedical Literature Database, Chinese Scientific Journal Database, and Wanfang Database from their inception to November 16, 2022. The selection of studies, risk of bias assessment, and data extraction were carried out independently by two authors. The statistical analysis was performed using STATA. Results: Our meta-analysis included a total of 35 studies with 2,833 patients, published between 2008 and 2022, with intervention durations ranging from 4 weeks to 12 months. However, most of the studies had a high risk of detection bias. Our findings indicated that the combination of donepezil and TCM significantly improved the Montreal Cognitive Assessment (MoCA) score (weighted mean difference [WMD] = 2.79, 95% confidence interval [CI]: 1.82 to 3.75) and the Barthel Index score (WMD = 9.20, 95% CI: 5.39 to 13.00) compared to donepezil alone. However, subgroup analyses showed that the MoCA score did not increase significantly in patients with MCI resulting from cerebrovascular disease (WMD = 1.47, 95% CI: -0.02 to 2.96). Conclusion: The combination of donepezil and TCM may have a more positive effect on cognitive function and activities of daily living in patients with MCI compared to the use of donepezil alone. However, due to the limited quality of the studies included in our analysis, these findings should be interpreted with caution.

Distinct evolution of ST11 KL64 Klebsiella pneumoniae in Taiwan.

Carbapenem-resistant ST11_KL64 Klebsiella pneumoniae emerged as a significant public health concern in Taiwan, peaking between 2013 and 2015, with the majority of isolates exhibiting OXA-48 as the sole carbapenemase. In this study, we employed whole-genome sequencing to investigate the molecular underpinnings of ST11_KL64 isolates collected from 2013 to 2021. Phylogenomic analysis revealed a notable genetic divergence between the ST11_KL64 strains in Taiwan and those in China, suggesting an independent evolutionary trajectory. Our findings indicated that the ST11_KL64_Taiwan lineage originated from the ST11_KL64 lineage in Brazil, with recombination events leading to the integration of ICEKp11 and a 27-kb fragment at the tRNAASN sites, shaping its unique genomic landscape. To further elucidate this unique sublineage, we examined the plasmid contents. In contrast to ST11_KL64_Brazil strains, which predominantly carried blaKPC-2, ST11_KL64_Taiwan strains exhibited the acquisition of an epidemic blaOXA-48-carrying IncL plasmid. Additionally, ST11_KL64_Taiwan strains consistently harbored a multi-drug resistance IncC plasmid, along with a collection of gene clusters that conferred resistance to heavy metals and the phage shock protein system via various Inc-type plasmids. Although few, there were still rare ST11_KL64_Taiwan strains that have evolved into hypervirulent CRKP through the horizontal acquisition of pLVPK variants. Comprehensive characterization of the high-risk ST11_KL64 lineage in Taiwan not only sheds light on its epidemic success but also provides essential data for ongoing surveillance efforts aimed at tracking the spread and evolution of ST11_KL64 across different geographical regions. Understanding the molecular underpinnings of CRKP evolution is crucial for developing effective strategies to combat its emergence and dissemination.

Hydrogen Sulfide Attenuates the Cognitive Dysfunction in Parkinson's Disease Rats via Promoting Hippocampal Microglia M2 Polarization by Enhancement of Hippocampal Warburg Effect.

Identification of innovative therapeutic targets for the treatment of cognitive impairment in Parkinson's disease (PD) is urgently needed. Hydrogen sulfide (H2S) plays an important role in cognitive function. Therefore, this work is aimed at investigating whether H2S attenuates the cognitive impairment in PD and the underlying mechanisms. In the rotenone- (ROT-) established PD rat model, NaHS (a donor of H2S) attenuated the cognitive impairment and promoted microglia polarization from M1 towards M2 in the hippocampus of PD rats. NaHS also dramatically upregulated the Warburg effect in the hippocampus of PD rats. 2-Deoxyglucose (2-DG, an inhibitor of the Warburg effect) abolished NaHS-upregulated Warburg effect in the hippocampus of PD rats. Moreover, the inhibited hippocampal Warburg effect by 2-DG abrogated H2S-excited the enhancement of hippocampal microglia M2 polarization and the improvement of cognitive function in ROT-exposed rats. Our data demonstrated that H2S inhibits the cognitive dysfunction in PD via promoting microglia M2 polarization by enhancement of hippocampal Warburg effect.

A nosocomial salmonellosis outbreak caused by blaOXA-48-carrying, extensively drug-resistant Salmonella enterica serovar Goldcoast in a hospital respiratory care ward in Taiwan.

OBJECTIVES: A nosocomial salmonellosis outbreak caused by Salmonella enterica serovar Goldcoast occurred in a respiratory care ward (RCW) of a hospital in central Taiwan between December 24, 2020, and January 21, 2021. Ten isolates recovered from 10 RCW residents were resistant to extended-spectrum cephalosporins. The resistance mechanism needs to be investigated. METHODS: Whole-genome sequencing and antimicrobial susceptibility testing were conducted to determine the genetic resistance determinants and the phenotypic resistance in the isolates. RESULTS: Each of the 10 outbreak isolates harbored an IncHI2 plasmid that carried 15 antimicrobial resistance genes aac(3)-IId, aadA22, aph(3')-Ia, aph(6)-Id, arr-2, blaCTX-M-55, blaLAP-2, blaTEM-1, dfrA14, floR, lnu(F), qnrS13, sul2, sul3, tet(A), an efflux pump regulatory gene ramAp and an IncL plasmid carried a blaOXA-48. The outbreak strains were expected to be resistant to numerous antimicrobials, including aminoglycosides, b-lactams /inhibitors, tetracycline, rifamycin, lincosamide, sulfonamides, trimethoprim, phenicols, fluoroquinolones, and carbapenems. Two outbreak isolates displayed higher minimum inhibitory concentrations than the other eight isolates to cefmetazole and carbapenems, which was linked to a deficiency of a major facilitator superfamily transporter in the two isolates. CONCLUSION: The carbapenem-resistant outbreak strains could have been derived from extensively drug-resistant S. enterica Goldcoast strains, which have been a major pathogen in Taiwan since 2018, through the acquisition of a blaOXA-48-carrying plasmid. Special efforts are needed in Taiwan to monitor the spread of extremely resistant strains.

Microevolution of CG23-I Hypervirulent Klebsiella pneumoniae during Recurrent Infections in a Single Patient.

CG23-I lineage constitutes the majority of hypervirulent Klebsiella pneumoniae. A diabetic patient suffered six episodes of infections caused by CG23-I K. pneumoniae. A total of nine isolates were collected in 2020. We performed whole-genome sequencing to elucidate the within-patient evolution of CG23-I K. pneumoniae. The maximum pairwise difference among the nine longitudinally collected isolates was five single nucleotide polymorphisms. One of the mutations was at the Asp87 position of GyrA. Four indels were identified, including an initiator tRNAfMet duplication, a tRNAArg deletion, a 7-bp insertion, and a 22-bp deletion. All 9 isolates had the genomic features of CG23-I K. pneumoniae, a chromosome-borne ICEKp10, and a large virulence plasmid. The carriage of a complete set of genes for the biosynthesis of colibactin by ICEKp10 gave the nine isolates an ability to cause DNA damage to RAW264.7 cells. Compared with the initial isolate, the last isolate with an additional copy of initiator tRNAfMet grew faster in a nutrient-limiting condition and exhibited enhanced virulence in BALB/c mice. Collectively, we characterized the within-patient microevolution of CG23-I K. pneumoniae through an in-depth comparison of genome sequences. Using the in vitro experiments and mouse models, we also demonstrated that these genomic alterations endowed the isolates with advantages to pass through in vivo selection. IMPORTANCE CG23-I is a significant lineage of hypervirulent Klebsiella pneumoniae. This study characterizes the within-patient microevolution of CG23-I K. pneumoniae. Selective pressures from continuous use of antibiotics favored point mutations contributing to bacterial resistance to antibiotics. The duplication of an initiator tRNAfMet gene helped CG23-I K. pneumoniae proliferate to reach a maximal population size during infections. For longer persistence inside a human host, the large virulence plasmid evolved with more flexible control of replication through duplication of the iteron-1 region. With the genomic alterations, the last isolate had a growth advantage over the initial isolate and exhibited enhanced virulence in BALB/c mice. This study gives us a deeper understanding of the genome evolution during the within-patient pathoadaptation of CG23-I K. pneumoniae.

Assessment of hypermucoviscosity as a virulence factor for experimental Klebsiella pneumoniae infections: comparative virulence analysis with hypermucoviscosity-negative strain.

BACKGROUND: Klebsiella pneumoniae displaying the hypermucoviscosity (HV) phenotype are considered more virulent than HV-negative strains. Nevertheless, the emergence of tissue-abscesses-associated HV-negative isolates motivated us to re-evaluate the role of HV-phenotype. RESULTS: Instead of genetically manipulating the HV-phenotype of K. pneumoniae, we selected two clinically isolated K1 strains, 1112 (HV-positive) and 1084 (HV-negative), to avoid possible interference from defects in the capsule. These well-encapsulated strains with similar genetic backgrounds were used for comparative analysis of bacterial virulence in a pneumoniae or a liver abscess model generated in either naïve or diabetic mice. In the pneumonia model, the HV-positive strain 1112 proliferated to higher loads in the lungs and blood of naïve mice, but was less prone to disseminate into the blood of diabetic mice compared to the HV-negative strain 1084. In the liver abscess model, 1084 was as potent as 1112 in inducing liver abscesses in both the naïve and diabetic mice. The 1084-infected diabetic mice were more inclined to develop bacteremia and had a higher mortality rate than those infected by 1112. A mini-Tn5 mutant of 1112, isolated due to its loss of HV-phenotype, was avirulent to mice. CONCLUSION: These results indicate that the HV-phenotype is required for the virulence of the clinically isolated HV-positive strain 1112. The superior ability of the HV-negative stain 1084 over 1112 to cause bacteremia in diabetic mice suggests that factors other than the HV phenotype were required for the systemic dissemination of K. pneumoniae in an immunocompromised setting.

[Orographic Influences on the Spatial Distribution of PM2.5 on the Fen-Wei Plain].

Topography not only has an effect on the spatial distribution of pollutants by restricting populations and industrial activities, but also affects the formation, transmission, accumulation, diffusion, and sedimentation of PM2.5. Topography is, therefore, an essential variable for understanding the spatial distribution of PM2.5, especially in basin areas. Based on gridded data and both natural and human indexes, this paper examines orographic effects on the distribution of PM2.5 on the Fen-Wei Plain based on the change point method, regression, the geographical detector method, and bivariate spatial autocorrelation. The results indicate that:① The relief amplitude of the plain is generally lower in its central part than at its edge, which is similar to the attitudinal distribution in this region; ② The distribution of PM2.5 is negatively related to relief amplitude, with high concentrations in central area and lower concentrations at the edge; ③ Based on the geographical detector analysis, PM2.5 patterns in this region are shaped by human factors including population, gross domestic product(GDP), and energy consumption, as well as natural factors including meteorological conditions and vegetation; and ④ Topography has a significant effect on both human and natural factors; an increase of relief amplitude is associated with a decrease in population, GDP, and energy consumption based on power function. Accordingly, temperature goes down linearly; precipitation, relative moisture, and wind speed increase linearly; and the vegetation index increases based on a logarithmic function.

Two ST11 Klebsiella pneumoniae strains exacerbate colorectal tumorigenesis in a colitis-associated mouse model.

Sequence type (ST) 11 is one of the major lineages of carbapenem-resistant Klebsiella pneumoniae (CRKP). Although the gastrointestinal (GI) carriage of CRKP predisposes individuals to subsequent infections, little is known for its impact on gut homeostasis. In this study, we investigated the association between ST11 CRKP colonization and colorectal cancer (CRC). Two ST11 CRKP, KPC160111 (KL47) and KPC160132 (KL64), were selected as the representative strains. We used azoxymethane (AOM) and dextran sodium sulfate (DSS) to initiate a colitis-associated CRC model. Both strains established prolonged colonization in the GI tract of the AOM-DSS-treated BALB/c mice and aggravated gut dysbiosis. Under this AOM-DSS-induced setting, ST11 K. pneumoniae colonization significantly promoted the growth and progression of colorectal adenomas to high-grade dysplasia. Numerous crypts were formed inside the enlarged adenomas, in which CD163+ tumor-associated macrophages accumulated. Similarly, ST11 K. pneumoniae also increased the population size of the CD163+ macrophages with the M2 phenotype in the peritoneal cavity of LPS-primed BALB/c mice. When applied to RAW264.7 cells, ST11 K. pneumoniae polarized the macrophages toward an M2 phenotype through the inhibition of IKK-NFκB and the activation of STAT6-KLF4-IL-10. Through the M2-skewing ability, ST11 K. pneumoniae promoted the accumulation of CD163+ macrophages in the adenomatous crypts to create an immunosuppressive niche, which not only accommodated the extended stay for its own sake but also deteriorated colorectal tumorigenesis.

Colonization dynamics of Klebsiella pneumoniae in the pet animals and human owners in a single household.

Klebsiella pneumoniae resides in the gastrointestinal (GI) microbiota of humans and animals. To characterize the population dynamics of GI-colonizing K. pneumoniae, we examined the clonality of K. pneumoniae isolates, which were longitudinally collected from the fecal samplings of a healthy married couple and their pet animals during Sep. 2015 to Oct. 2016. As revealed by XbaI-PFGE analysis, the K. pneumoniae populations detected in the male owner and in one of the dogs, consisted of clonally diverse K. pneumoniae isolates; whereas, a dominant clone persisted in the GI tract of the female owner who was prone to chronic diarrhea. Whole-genome sequencing analysis of a representative strain of this pathobiont clone revealed a sequence type (ST) 29 lineage with the carriage of KL54 cps locus and a 192,603 bp IncHIB-type virulence plasmid. After probiotics intervention, the pathobiont K. pneumoniae diminished. The vacant niche was transiently occupied by other clones of K. pneumoniae, one of which was also present in the male owner. Besides the dog, the fecal carriage of K. pneumoniae was also detected in a pet turtle. This turtle isolate was resistant to multiple antimicrobials, including carbapenems. Possible transmission of drug-resistant K. pneumoniae through human-pet bonds warrants our attention.

The ALOXE3 gene variants from patients with Dravet syndrome decrease gene expression and enzyme activity.

Aberrant expression or dysfunction of a number of genes in the brain contributes to epilepsy, a common neurological disorder characterized by recurrent seizures. Local overexpression of arachidonate lipoxygenase 3 (ALOXE3), a key enzyme for arachidonic acid (AA) metabolic pathway, alleviates seizure severities. However, the relationship between the ALOXE3 gene mutation and epilepsy has not been reported until now. Here we firstly characterized the promoter of human ALOXE3 gene and found that the ALOXE3 promoter could drive luciferase gene expression in the human HEK-293 and SH-SY5Y cells. We then screened the ALOXE3 promoter region and all coding exons from those patients with Dravet syndrome and identified 5 variants c.-163T > C, c.-50C > G, c.-37G > A, c. + 228G > A and c. + 290G > T in the promoter region and one missense variant c.1939A > G (p.I647 V) in the exon. Of these variants in the promoter region, only -50C > G was a novel variant located on the transcriptional factor NFII-I binding element. Luciferase reporter gene analyses indicated that the c.-50C > G could decrease gene expression by preventing the TFII-I's binding. In addition, the variant p.I647 V was conserved among all analyzed species and located within the ALOXE3 functional domain for catalyzing its substrate. In cultured cell lines, overexpression of ALOXE3 significantly decreased the cellular AA levels and overexpression of ALOXE3-I647 V could restore the AA levels, suggesting that the p.I647 V mutant led to a decrease in enzyme activity. Taken together, the present study proposes that the identified ALOXE3 variants potentially contribute to the AA-pathway-mediated epileptogenesis, which should provide a novel avenue for clinical diagnosis of epilepsy.