TIFAB regulates the TIFA-TRAF6 signaling pathway involved in innate immunity by forming a heterodimer complex with TIFA.

Nuclear factor κB (NF-κB) is activated by various inflammatory and infectious molecules and is involved in immune responses. It has been elucidated that ADP-ß-D-manno-heptose (ADP-Hep), a metabolite in gram-negative bacteria, activates NF-κB through alpha-kinase 1 (ALPK1)-TIFA-TRAF6 signaling. ADP-Hep stimulates the kinase activity of ALPK1 for TIFA phosphorylation. Complex formation between phosphorylation-dependent TIFA oligomer and TRAF6 promotes the polyubiquitination of TRAF6 for NF-κB activation. TIFAB, a TIFA homolog lacking a phosphorylation site and a TRAF6 binding motif, is a negative regulator of TIFA-TRAF6 signaling and is implicated in myeloid diseases. TIFAB is indicated to regulate TIFA-TRAF6 signaling through interactions with TIFA and TRAF6; however, little is known about its biological function. We demonstrated that TIFAB forms a complex not with the TIFA dimer, an intrinsic form of TIFA involved in NF-κB activation, but with monomeric TIFA. The structural analysis of the TIFA/TIFAB complex and the biochemical and cell-based analyses showed that TIFAB forms a stable heterodimer with TIFA, inhibits TIFA dimer formation, and suppresses TIFA-TRAF6 signaling. The resultant TIFA/TIFAB complex is a "pseudo-TIFA dimer" lacking the phosphorylation site and TRAF6 binding motif in TIFAB and cannot form the orderly structure as proposed for the phosphorylated TIFA oligomer involved in NF-κB activation. This study elucidated the molecular and structural basis for the regulation of TIFA-TRAF6 signaling by TIFAB.

Idiotopes of antibodies against HIV-1 CD4-induced epitope shared with those against microorganisms.

Induction of antibodies (Abs) against the conformational CD4-induced (CD4i) epitope is frequent in HIV-1 infection. However, the mechanism of development of anti-CD4i Abs is unclear. We used anti-idiotypic (aID) monoclonal Abs (mAbs) of anti-CD4i mAbs to isolate anti-CD4i mAbs from infected subjects and track the causative antigens. One anti-aID mAb sorted from infected subjects by aID mAbs had the characteristics of anti-CD4i Abs, including IGHV1-69 usage and ability to bind to HIV-1 Env enhanced by sCD4. Critical amino acid sequences for the binding of six anti-aID mAbs, with shared idiotope to anti-CD4i mAbs, were analysed by phage display. The identified amino acid sequences showed similarity to proteins from human microbiota and infectious agents. Peptides synthesized from Caudoviricetes sp and Vibrio vulnificus based on the identified sequences were reactive to most anti-aID and some anti-CD4i mAbs. These results suggest that anti-CD4i Abs may evolve from B cells primed by microorganisms.

Contribution of Phe112, Ser114, and Tyr115 to Drug-Binding Selectivity in the A Variant of α1-Acid Glycoprotein.

The plasma protein α1-acid glycoprotein (AGP) primarily affects the pharmacokinetics of basic drugs. There are two AGP variants in humans, A and F1*S, exhibiting distinct drug-binding selectivity. Elucidation of the drug-binding selectivity of human AGP variants is essential for drug development and personalized drug therapy. Herein, we aimed to establish the contribution of amino acids 112 and 114 of human AGP to drug-binding selectively. Both amino acids are located in the drug-binding region and differ between the variants. Phe112/Ser114 of the A variant and its equivalent residues in the F1*S variant (Leu112/Phe114) were swapped with each other. Binding experiments were then conducted using the antiarrhythmic drug disopyramide, which selectively binds to the A variant. A significant decrease in the bound fraction was observed in each singly mutated A protein (Phe112Leu or Ser114Phe). Moreover, the bound fraction of the double A mutant (Phe112Leu/Ser114Phe) was decreased to that of wild-type F1*S. Intriguingly, the double F1*S mutant (Leu112Phe/Phe114Ser), in which residues were swapped with those of the A variant, showed only partial restoration in binding. The triple F1*S mutant (Leu112Phe/Phe114Ser/Asp115Tyr), where position 115 is thought to contribute to the difference in pocket size between variants, showed a further recovery in binding to 70% of that of wild-type A. These results were supported by thermodynamic analysis and acridine orange binding, which selectively binds the A variant. Together, these data indicate that, in addition to direct interaction with Phe112 and Ser114, the binding pocket size contributed by Tyr115 is important for the drug-binding selectivity of the A variant.

Risk factors for cefmetazole-non-susceptible bacteremia in acute cholangitis.

INTRODUCTION: Cefmetazole (CMZ), an antibiotic with limited international distribution, is recommended by the Tokyo Guidelines 2018 (TG18) for non-severe cases of acute cholangitis (AC). However, the risk factors for CMZ-non-susceptible (CMZ-NS) bacteremia in AC remain unclear. Here, we aimed to investigate the risk factors for CMZ-NS bacteremia and evaluate mortality in patients with AC. METHODS: This single-center, retrospective, observational study included all patients diagnosed with definite bacteremic AC, based on TG18, from April 2019 to March 2023. Risk factors for CMZ-NS bacteremia were analyzed by univariate, and age- and sex-adjusted, logistic regression analyses. Mortality was compared by cause of obstruction, CMZ-susceptible/CMZ-NS bacteremia, and initial treatment. RESULTS: In total, 165 patients were enrolled. CMZ-NS bacteremia was diagnosed in 46 (27.9 %) patients. Histories of diabetes mellitus, hepato-biliary-pancreatic cancer, malignant biliary obstruction, and endoscopic sphincterotomy were identified as significant factors associated with the risk of CMZ-NS bacteremia. Thirteen patients died within 30 days of hospital admission. The mortality of patients with AC and malignant biliary obstruction was statistically higher than that of patients with bile duct stones. No patients with AC and bile duct stones died in the group with CMZ-NS bacteremia and inappropriate initial antibiotics. CONCLUSIONS: In AC, a history of diabetes mellitus, hepato-biliary-pancreatic cancer, malignant biliary obstruction, and endoscopic sphincterotomy are associated with an increased risk of CMZ-NS bacteremia. Therefore, the choice of empiric therapy for AC should be based on the etiology and patient background, rather than on the severity.

Catheter-related bloodstream infection caused by Lacticaseibacillus paracasei: A case report and literature review.

Catheter-related bloodstream infections (CRBSIs) caused by Lactobacillus spp. and Lacticaseibacillus spp. are rare, and their clinical course and optimal treatment remain uncertain. In this report, we present a 46-year-old male patient who experienced clinically diagnosed Lacticaseibacillus paracasei CRBSI on four separate occasions, despite receiving systemic administration of antibiotics and antimicrobial lock therapy. The patient did not develop L. paracasei bacteremia after catheter removal. This case report furthers our knowledge of CRBSI caused by Lactobacillus and related genera and highlights the need for further research.

Surgical antimicrobial prophylaxis in Japanese hospitals: Real status and challenges.

BACKGROUND: Information regarding the status of surgical antimicrobial prophylaxis (SAP) in Japanese hospitals is lacking. This study aimed to explore the status of SAP prescriptions for surgeries and adherence to Japanese SAP guidelines. METHODS: From February to July 2020, a 1-day multicentre point prevalent survey was conducted at 27 hospitals in Aichi Prefecture, Japan. Patients prescribed SAP were included in this study. The appropriateness of the SAP was evaluated based on the guidelines for selection of antimicrobials and their duration. Surgery was defined as appropriate when all the items were appropriate. RESULTS: A total of 728 patients (7.1 %; 728/10,199) received antimicrobials for SAP. Among them, 557 patients (76.5 %, 557/728) underwent the surgeries described in the guidelines. The overall appropriateness of all surgeries was 33.9 % (189/557). The appropriate selection of antimicrobial before/during and after surgery and their durations were 67.5 % (376/557), 67.5 % (376/557), and 43.3 % (241/557), respectively. The overall appropriateness ranged from 0 % (0/37, oral and maxillofacial surgery) to 58.7 % (88/150, orthopaedic surgery) and 27.7 % (36/130, community hospitals with 400-599 beds) to 47.2 % (17/36, specific hospitals). Cefazolin was the most prevalent antimicrobial prescribed before/during (55.5 %, 299/539), and after (45.1 %, 249/552) surgery. In total, 101 oral antimicrobials were prescribed postoperatively. CONCLUSIONS: SAP adherence by specific surgical fields and hospitals was shown in this study. Intensive intervention and repeated surveillance are necessary to improve SAP prescriptions in Japanese hospitals.

Structure of the mammalian adenine DNA glycosylase MUTYH: insights into the base excision repair pathway and cancer.

Mammalian MutY homologue (MUTYH) is an adenine DNA glycosylase that excises adenine inserted opposite 8-oxoguanine (8-oxoG). The inherited variations in human MUTYH gene are known to cause MUTYH-associated polyposis (MAP), which is associated with colorectal cancer. MUTYH is involved in base excision repair (BER) with proliferating cell nuclear antigen (PCNA) in DNA replication, which is unique and critical for effective mutation-avoidance. It is also reported that MUTYH has a Zn-binding motif in a unique interdomain connector (IDC) region, which interacts with Rad9-Rad1-Hus1 complex (9-1-1) in DNA damage response, and with apurinic/apyrimidinic endonuclease 1 (APE1) in BER. However, the structural basis for the BER pathway by MUTYH and its interacting proteins is unclear. Here, we determined the crystal structures of complexes between mouse MUTYH and DNA, and between the C-terminal domain of mouse MUTYH and human PCNA. The structures elucidated the repair mechanism for the A:8-oxoG mispair including DNA replication-coupled repair process involving MUTYH and PCNA. The Zn-binding motif was revealed to comprise one histidine and three cysteine residues. The IDC, including the Zn-binding motif, is exposed on the MUTYH surface, suggesting its interaction modes with 9-1-1 and APE1, respectively. The structure of MUTYH explains how MAP mutations perturb MUTYH function.

Current Status of Outpatient Oral Antimicrobial Prescription and the Influence of Antimicrobial Stewardship for Inpatients: A Repeated Cross-Sectional Study at a Japanese Community Hospital.

This study aimed to clarify the details of outpatient oral antimicrobial use (AMU) at a Japanese community hospital and investigate the influence of the current inpatient-based antimicrobial stewardship (AS) on outpatients. A repeated cross-sectional study was conducted in Komaki City Hospital. Data on patients, physicians, and oral antibiotics were collected in October 2013, 2016, and 2019, and appropriateness of treatment and surgical antimicrobial prophylaxis (SAP) was evaluated. The percentage of patients receiving oral antibiotics increased significantly from 4.7% in 2013 (345/7338) to 5.9% in 2019 (365/6146), and the overall number of antimicrobial prescriptions per 1000 outpatients increased from 51.8 in 2013 to 68.0 in 2019. Prescriptions for third-generation cephalosporins per 1000 outpatients decreased (from 21.4 to 6.3), whereas the number of prescriptions for penicillin (from 3.8 to 15.3), fluoroquinolones (from 7.0 to 13.2), and co-trimoxazole (from 5.0 to 15.8) increased from 2013 to 2019. The appropriate AMU for overall infections significantly increased (from 68.4% in 2013 to 83.7% in 2019). The choice and duration of AMU significantly improved for SAP. However, even in 2019, only 29.3% of patients received antibiotics before surgery. The improved selection of antibiotics on outpatient prescription may be due to the influence of AS-which is focused on inpatients-while prescriptions for fluoroquinolones and prophylactics also increased. The challenges of antimicrobial administration after surgeries were also highlighted.

Cholangitis with Sphingobacterium multivorum and Acinetobacter junii bacteremia in a patient with gastric cancer: A case report.

INTRODUCTION: Sphingobacterium is an aerobic, glucose non-fermenting, Gram-negative rod bacterium that has been isolated from soil, plants, food, and water sources, including in hospitals. Reports of systemic infections caused by Sphingobacterium multivorum (S. multivorum) are rare, and their clinical and microbiological characteristics remain unclear. Moreover, conventional microbiological methods have limited ability to identify S. multivorum. We report the first case of obstructive cholangitis with bacteremia caused by S. multivorum in a patient with gastric cancer. CASE REPORT: A 68-year-old woman with advanced gastric cancer, hypertension, and hyperlipidemia was admitted with obstructive jaundice, and subsequently developed obstructive cholangitis during the hospital stay. S. multivorum were identified by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and 16S ribosomal RNA sequencing of the patient's blood samples. Based on the antibiotic susceptibility results of the isolates, cefepime was administered intravenously for 14 days, with good therapeutic outcomes. CONCLUSIONS: S. multivorum infection is rare, and its microbiology and pathogenicity in humans is mostly unknown. Therefore, multiple diagnostic approaches should be used to identify S. multivorum, and antimicrobial therapy should be selected based on the in vitro susceptibility. This report provides clinicians with novel information on the clinical manifestations and diagnostic methods for an accurate diagnosis of S. multivorum.

Difficulties in diagnosing Malassezia furfur bloodstream infection and possibility of spontaneous resolution in a patient undergoing chemotherapy for neuroblastoma: A case report.

Malassezia furfur is a lipophilic, yeast-like fungus that forms part of the normal human skin microflora and is associated with a wide range of infections, such as pityriasis versicolor, folliculitis, and systemic infections in immunocompromised patients. Although matrix-assisted laser desorption/ionization time-of-flight mass spectrometry has enabled rapid identification of Malassezia species, it is still a challenge to diagnose systemic infections because Malassezia fungemia can often be missed by automated blood culture systems. We report a case in which M. furfur in blood was detected by the presence of yeast-like fungi in blood smears. Yeast-like organisms were observed in the blood smears of a 3-year-old boy, taken over 2 weeks without any symptoms. He had undergone several courses of chemotherapy for neuroblastoma via an indwelling central venous catheter (CVC) that was placed in his right anterior chest for 11 months. Although the blood cultures obtained from an automated blood culture system were negative, M. furfur growth was detected in the subcultured blood taken from the CVC. The CVC was removed, and the scheduled chemotherapy was postponed. No systemic M. furfur bloodstream infection occurred; the infection resolved spontaneously without any specific treatment; only prophylactic fluconazole was administered. M. furfur fungemia may not be diagnosable by an automated blood culture system. Further, M. furfur may not cause infections in humans even when administered intravenously. This report may lead to the discovery of factors related to human infectivity of this disease in the future.

Lysinibacillus fusiformis bacteremia: Case report and literature review.

A 93-year-old woman was diagnosed with Lysinibacillus fusiformis bacteremia complicated with coma blisters. Initial gram staining for L. fusiformis indicated the presence of gram-negative rods; however, subsequent staining of colonies from Mueller-Hinton agar revealed the presence of gram-positive and gram-negative rods with spherical endospores, and Matrix-Assisted Laser Desorption/Ionization Time-of-Flight Mass Spectrometry (VITEK ® MS and microflex® LT/SH) definitively identified the organism as L. fusiformis. The two-week administration of piperacillin/tazobactam and ampicillin resulted in an improvement of the patient's general condition, and the skin lesions gradually improved.

Genetic and epidemiological analysis of ESBL-producing Klebsiella pneumoniae in three Japanese university hospitals.

INTRODUCTION: We aimed to clarify the genetic background and molecular epidemiology of extended-spectrum beta-lactamase (ESBL)-producing Klebsiella pneumoniae (K. pneumoniae) at three geographically separated university hospitals in Japan. METHODS: From January 2014 to December 2016, 118 ESBL-producing K. pneumoniae (EPKP) strains that were detected and stored at three university hospitals were collected. Molecular epidemiological analysis was performed using enterobacterial repetitive intergenic consensus (ERIC)-polymerase chain reaction (PCR) and multi-locus sequence typing (MLST). The ESBL type was determined using the PCR-sequence method. The presence of plasmid-mediated fluoroquinolone resistance (PMQR) genes was analyzed by PCR. We compared the relationships between PMQR gene possession/quinolone resistance-determining region (QRDR) mutation and levofloxacin (LVFX)/ciprofloxacin (CPFX) susceptibility. RESULTS: The detection rate of EPKP was 4.8% (144/2987 patients). MLST analysis revealed 62 distinct sequence types (STs). The distribution of STs was diverse, and only some EPKP strains had the same STs. ERIC-PCR showed discriminatory power similar to that of MLST. The major ESBL genotypes were CTX-M-15-, CTX-M-14-, and SHV-types, which were detected in 47, 30, and 27 strains, respectively. Ninety-one out of 118 strains had PMQR genes and 14 out of 65 strains which were not susceptible to CPFX had QRDR mutations, and the accumulation of PMQR genes and QRDR mutations tended to lead to higher minimum inhibitory concentrations (MICs) of LVFX. CONCLUSIONS: At three geographically separated university hospitals in Japan, the epidemiology of EPKP was quite diverse, and no epidemic strains were found, whereas CTX-M-14 and CTX-M-15 were predominant.

Epidemiology and molecular characterization of fecal carriage of third-generation cephalosporin-resistant Enterobacterales among elderly residents in Japan.

INTRODUCTION: The spread of third-generation cephalosporin-resistant Gram-negative bacteria is a serious concern in acute and post-acute care settings. This study aimed to understand the epidemiology and molecular background of fecal colonization of resistant Enterobacterales in elderly people. METHODS: In December 2015-December 2017, stool or rectal swab samples were collected from 101 elderly patients receiving home care, using long-term care facilities (LTCF), and living in nursing homes repeatedly at 3-9-month intervals. Patient clinical background data were collected from medical records. After phenotypic screening for extended-spectrum ß-lactamase (ESBL), AmpC-type ß-lactamase or carbapenemase production, drug resistance genes of isolates were analyzed using polymerase chain reaction (PCR). ESBL-producing Escherichia coli isolates obtained from the same patients in repetitive screenings were analyzed using PCR-based ORF typing. Risk factors for persistent carriage of resistant Enterobacterales were analyzed using multivariate analysis. RESULTS: Resistant Enterobacterales isolates were detected in 37 of 101 (36.6%) and 29 of 80 (36.3%) residents in first and second screenings, respectively. ESBL-producing E. coli accounted for 80% isolates, the most common being CTX-M-9-group ß-lactamase producers. Molecular epidemiological analysis revealed probable transmissions of ESBL-producing E. coli; 58% of ESBL-producing E. coli colonizers were persistent colonizers at least after 3 -month intervals. Age > 87 years and LTCF residence were independent risk factors for persistent carriage of ESBL-producing E. coli. CONCLUSIONS: We showed, for the first time, high persistent colonization rate of ESBL-producing E. coli among elderly people in post-acute care settings with probable horizontal transmission. We also identified significant risk factors for persistent colonization.

Expression, Purification and Characterization of CAR/NCOA-1 Tethered Protein in E. coli Using Maltose-Binding Protein Fusion Tag and Gelatinized Corn Starch.

The constitutive active/androstane receptor (CAR) is a nuclear receptor that functions as a xenobiotic sensor, which regulates the expression of enzymes involved in drug metabolism and of efflux transporters. Evaluation of the binding properties between CAR and a drug was assumed to facilitate the prediction of drug-drug interaction, thereby contributing to drug discovery. The purpose of this study is to construct a system for the rapid evaluation of interactions between CAR and drugs. We prepared recombinant CAR protein using the Escherichia coli expression system. Since isolated CAR protein is known to be unstable, we designed a fusion protein with the CAR binding sequence of the nuclear receptor coactivator 1 (NCOA1), which was expressed as a fusion protein with maltose binding protein (MBP), and purified it by several chromatography steps. The thus-obtained CAR/NCOA1 tethered protein (CAR-NCOA1) was used to evaluate the interactions of CAR with agonists and inverse agonists by a thermal denaturation experiment using differential scanning fluorometry (DSF) in the presence and absence of drugs. An increase in the melting temperature was observed with the addition of the drugs, confirming the direct interaction between them and CAR. DSF is easy to set up and compatible with multiwell plate devices (such as 96-well plates). The use of DSF and the CAR-NCOA1 fusion protein together allows for the rapid evaluation of the interaction between a drug and CAR, and is thereby considered to be useful in drug discovery.

Nonlinear ICA of fMRI reveals primitive temporal structures linked to rest, task, and behavioral traits.

Accumulating evidence from whole brain functional magnetic resonance imaging (fMRI) suggests that the human brain at rest is functionally organized in a spatially and temporally constrained manner. However, because of their complexity, the fundamental mechanisms underlying time-varying functional networks are still not well understood. Here, we develop a novel nonlinear feature extraction framework called local space-contrastive learning (LSCL), which extracts distinctive nonlinear temporal structure hidden in time series, by training a deep temporal convolutional neural network in an unsupervised, data-driven manner. We demonstrate that LSCL identifies certain distinctive local temporal structures, referred to as temporal primitives, which repeatedly appear at different time points and spatial locations, reflecting dynamic resting-state networks. We also show that these temporal primitives are also present in task-evoked spatiotemporal responses. We further show that the temporal primitives capture unique aspects of behavioral traits such as fluid intelligence and working memory. These results highlight the importance of capturing transient spatiotemporal dynamics within fMRI data and suggest that such temporal primitives may capture fundamental information underlying both spontaneous and task-induced fMRI dynamics.

Albumin domain mutants with enhanced Aß binding capacity identified by phage display analysis for application in various peripheral Aß elimination approaches of Alzheimer's disease treatment.

Deposition of amyloid protein, particularly Aß1-42 , is a major contributor to the onset of Alzheimer's disease (AD). However, almost no deposition of Aß in the peripheral tissues could be found. Human serum albumin (HSA), the most abundant protein in the blood, has been reported to inhibit amyloid formation through binding Aß, which is believed to play an important role in the peripheral clearance of Aß. We identified the Aß binding site on HSA and developed HSA mutants with high binding capacities for Aß using a phage display method. HSA fragment 187-385 (Domain II) was found to exhibit the highest binding capacity for Aß compared with the other two HSA fragments. To elucidate the sequence that forms the binding site for Aß on Domain II, a random screening of Domain II display phage biopanning was constructed. A number of mutants with higher Aß binding capacities than the wild type were identified. These mutants exhibited stronger scavenging abilities than the wild type, as revealed via in vitro equilibrium dialysis of Aß experiments. These findings provide useful basic data for developing a safer alternative therapy than Aß vaccines and for application in plasma exchange as well as extracorporeal dialysis.

Fungal endocarditis after transcatheter aortic valve replacement (TAVR): Case report and review of literature.

The reported number of transcatheter aortic valve replacement-associated infective endocarditis (TAVR-IE) cases has been increasing worldwide, but information about the incidence and clinical features of fungal TAVR-IE is quite limited. We present a patient who acquired TAVR-IE caused by Candida parapsilosis four month after TAVR, who was successfully treated redo-aortic valve replacement and prolonged antifungal therapy.

Cyclization of Single-Chain Fv Antibodies Markedly Suppressed Their Characteristic Aggregation Mediated by Inter-Chain VH-VL Interactions.

Single-chain Fv (scFv) antibodies are recombinant proteins in which the variable regions of the heavy chain (VH) and light chain (VL) are connected by a short flexible polypeptide linker. ScFvs have the advantages of easy genetic manipulation and low-cost production using Escherichia coli compared with monoclonal antibodies, and are thus expected to be utilized as next-generation medical antibodies. However, the practical use of scFvs has been limited due to low homogeneity caused by their aggregation propensity mediated by inter-chain VH-VL interactions. Because the interactions between the VH and VL domains of antibodies are generally weak, individual scFvs are assumed to be in equilibrium between a closed state and an open state, in which the VH and VL domains are assembled and disassembled, respectively. This dynamic feature of scFvs triggers the formation of dimer, trimer, and larger aggregates caused by the inter-chain VH-VL interactions. To overcome this problem, the N-terminus and C-terminus were herein connected by sortase A-mediated ligation to produce a cyclic scFv. Open-closed dynamics and aggregation were markedly suppressed in the cyclic scFv, as judged from dynamic light scattering and high-speed atomic force microscopy analyses. Surface plasmon resonance and differential scanning fluorometry analysis revealed that neither the affinity for antigen nor the thermal stability was disrupted by the scFv cyclization. Generality was confirmed by applying the present method to several scFv proteins. Based on these results, cyclic scFvs are expected to be widely utilized in industrial and therapeutic applications.

Characterization of Non-amyloidogenic G101S Transthyretin.

Transthyretin (TTR) is a tetrameric beta-sheet-rich protein that is important in the plasma transport of thyroxine and retinol. Mutations in the TTR gene cause TTR tetramer protein to dissociate to monomer, which is the rate-limiting step in familial amyloid polyneuropathy. Amyloidogenicity of individual TTR variants depends on the types of mutation that induce significant changes in biophysical, biochemical and/or biological properties. G101S TTR variant was previously identified in a Japanese male without amyloidotic symptom, and was considered as a non-amyloidogenic TTR variant. However, little is known about G101S TTR. Here, we found slight but possibly important biophysical differences between wild-type (WT) and G101S TTR. G101S TTR had slower rate of tetramer dissociation and lower propensity for amyloid fibril formation, especially at mild low pH (4.2 and 4.5), and was likely to have strong hydrophobic interaction among TTR monomers, suggesting relatively higher stability of G101S TTR compared with WT TTR. Cycloheximide (CHX)-based assay in HEK293 cells revealed that intracellular G101S TTR expression level was lower, but extracellular expression was higher than WT TTR, implying enhanced secretion efficiency of G101S TTR protein compared with WT TTR. Moreover, we found that STT3B-dependent posttranslational N-glycosylation at N98 residue occurred in G101S TTR but not in other TTR variants, possibly due to amino acid alterations that increase N-glycosylation preference or accelerate rigid structure formation susceptible to N-glycosylation. Taken together, our study characterizes G101S TTR as a stable and N-glycosylable TTR, which may be linked to its non-amyloidogenic characteristic.

Active surveillance in response to the identification of a single carbapenemase-producing Escherichia coli at a Japanese university hospital.

This report described the experience of active surveillance culture implemented in response to the identification of a single carbapenemase-producing Escherichia coli in a Japanese university hospital. It revealed a horizontal transmission event and an additional asymptomatic carrier of carbapenemase-producing Escherichia coli with unique drug susceptibility and resistance gene profiles. Early implementation of active surveillance culture as a part of multifaceted infection control measures appeared to be useful to control further transmission of carbapenemase-producing Escherichia coli even in the low endemic facility. Further investigations on the timing and usefulness of active surveillance culture in the control of carbapenemase-producing Enterobacteriaceae would be warranted.