RelA is a global regulator for stationary phase development in the model bacterium Bacillus subtilis. The relA gene forms a bicistronic operon with the downstream dtd gene. In this study, we ...evaluated the significance of RelA and DTD proteins in spore formation and toxin production by an important gastrointestinal pathogen Clostridium perfringens. Our β-glucuronidase assay showed that in C. perfringens strain SM101, relA forms a bicistronic operon with its downstream dtd gene, and the relA promoter is expressed during both vegetative and sporulation conditions. By constructing double relA dtd and single dtd mutants in C. perfringens SM101, we found that: (1) RelA is required for maintaining the efficient growth capacity of SM101 cells during vegetative conditions; (2) both RelA and DTD are required for spore formation and enterotoxin (CPE) production by SM101; (3) RelA/DTD activate CodY, which is known to activate spore formation and CPE production in SM101 by activating a key sporulation-specific σ factor F; (4) as expected, RelA/DTD activate sporulation-specific σ factors (σ
, σ
, σ
and σ
) by positively regulating Spo0A production; and finally (5) RelA, but not DTD, negatively regulates phospholipase C (PLC) production by repressing plc gene expression. Collectively, our results demonstrate that RelA modulates cellular physiology such as growth, spore formation and toxin production by C. perfringens type A strain SM101, although DTD also plays a role in these pleiotropic functions in coordination with RelA during sporulation. These findings have implications for the understanding of the mechanisms involved in the infectious cycle of C. perfringens.
Thioredoxin-interacting protein (TXNIP), which has a tumor-suppressive function, is underexpressed in some human cancers. The function of TXNIP in vivo in carcinogenesis is not fully understood. ...Here, we show TXNIP to be downregulated in human bladder cancer according to grade and stage and also that loss of TXNIP expression facilitates bladder carcinogenesis using a mouse bladder cancer model. N-butyl-N-(4-hydroxybutyl) nitrosamine (BBN)-induced bladder cancer was found in 100% of Txnip knockout (KO) mice at week 8 of 0.025% BBN administration but in only 22% of wild-type (WT) mice at the same point. Among growth stimulators, phospho-extracellular signal-regulated kinase (pERK) expression was stronger during bladder carcinogenesis in Txnip-KO mice than in WT mice. We then evaluated TXNIP's effects on ERK activation through various growth stimulators and their receptors. Overexpression of TXNIP in human bladder cancer cells attenuated pERK expression upon stimulation with stromal cell-derived factor-1 (SDF-1) but not with epidermal growth factor or insulin-like growth factor-1. In Txnip-KO mice, immunohistochemical analysis showed enhanced expression of C-X-C chemokine receptor type 4 (CXCR4), the receptor of SDF-1, and of pERK in urothelial cells during BBN-induced bladder carcinogenesis. Finally, subcutaneous injection of CXCR4 antagonist, TF14016, attenuated pERK in urothelial cells and suppressed bladder carcinogenesis. These data indicate that TXNIP negatively regulates bladder carcinogenesis by attenuating SDF-1-CXCR4-induced ERK activation. This signal transduction pathway can be a potent target in preventing or treating bladder cancer.
Abstract We investigated BRO-β-lactamase production of Moraxella catarrhalis isolates and its antimicrobial susceptibility to β-lactams. Of the 233 isolates, 232 were BRO producers and 224 were BRO-1 ...producers. Four isolates exhibited elevated ceftriaxone minimum inhibitory concentration (2 μg/mL) and different pulsed-field gel electrophoresis patterns and we expect this number to increase in the near future.
We identified a Moraxella catarrhalis strain with high-level resistance to azithromycin (MIC>256 mg l(-1)), NSH1, isolated from nasopharyngeal swab samples from an inpatient with acute bronchitis in ...a Japanese hospital in 2011 and determined its mechanism of macrolide-lincosamide resistance. Antimicrobial susceptibility of M. catarrhalis strains was determined using the Etest and agar dilution methods. Mutations in the four 23S rRNA alleles, the ribosomal proteins L4 and L22, and methylase genes erm(B) and erm(F) were tested by PCR and/or sequencing. The efflux system was examined using appropriate inhibitors. Transformation experiments were performed using DNA amplicons of the 23S rRNA gene of M. catarrhalis strain NSH1. This strain showed high-level resistance to erythromycin, clarithromycin, azithromycin, clindamycin (MICs>256 mg l(-1)) and josamycin (MIC = 128 mg l(-1)), and contained the A2058T mutation (Escherichia coli numbering) in four of the 23S rRNA alleles. Mutation of the ribosomal proteins and overproduction of the efflux system were not observed, and methylase genes were not detected. When amplified DNA containing the single A2058T mutation was transformed into M. catarrhalis strains, transformants with three A2058T-mutated 23S rRNA alleles showed high-level resistance to macrolide-lincosamide, similar to strain NSH1. In contrast, transformants with two A2058T-mutated 23S rRNA alleles showed low-level MICs (azithromycin: 0.38-0.5 mg l(-1)). Thus, a single A2058T mutation occurring in at least three 23S rRNA alleles confers high-level resistance to 14-, 15- and 16-membered macrolides and lincosamides in M. catarrhalis possessing four 23S rRNA alleles. This study represents the first evidence, to our knowledge, of this effect in M. catarrhalis.
Klebsiella pneumoniae (Kp) is one of the most important nosocomial pathogens worldwide, able to cause multiorgan infections and hospital outbreaks. One of the most widely disseminated lineage of Kp ...is the clonal group 258 (CG258), which includes the highly resistant "high-risk" sequence types ST258 and ST11. Genomic investigations revealed that very large recombination events have occurred during the emergence of Kp lineages. A striking example is provided by ST258, which has undergone a recombination event that replaced over 1 Mb of the genome with DNA from an unrelated Kp donor. Although several examples of this phenomenon have been documented in Kp and other bacterial species, the significance of these very large recombination events for the emergence of either hypervirulent or resistant clones remains unclear. Here, we present an analysis of 834 Kp genomes that provides data on the frequency of these very large recombination events (defined as those involving >100 kb), their distribution within the genome, and the dynamics of gene flow within the Kp population. We note that very large recombination events occur frequently, and in multiple lineages, and that the majority of recombinational exchanges are clustered within two overlapping genomic regions, which have been involved by recombination events with different frequencies. Our results also indicate that certain lineages are more likely to act as donors to CG258. Furthermore, comparison of gene content in CG258 and non-CG258 strains agrees with this pattern, suggesting that the success of a large recombination depends on gene composition in the exchanged genomic portion.
The recently developed PCR-based open reading frame typing (POT) method is a useful molecular typing tool. Here, we evaluated the performance of POT for molecular typing of methicillin-resistant ...Staphylococcus aureus (MRSA) isolates and compared its performance to those of multilocus sequence typing (MLST) and Staphylococcus protein A gene typing (spa typing). Thirty-seven MRSA isolates were collected between July 2012 and May 2015. MLST, spa typing, and POT were performed, and their discriminatory powers were evaluated using Simpson's index analysis. The MRSA isolates were classified into 11, 18, and 33 types by MLST, spa typing, and POT, respectively. The predominant strains identified by MLST, spa typing, and POT were ST8 and ST764, t002, and 93-191-127, respectively. The discriminatory power of MLST, spa typing, and POT was 0.853, 0.875, and 0.992, respectively, indicating that POT had the highest discriminatory power.
Moreover, the results of MLST and spa were available after 2 days, whereas that of POT was available in 5 h. Furthermore, POT is rapid and easy to perform and interpret. Therefore, POT is a superior molecular typing tool for monitoring nosocomial transmission of MRSA.
Within the leading-order, single-active-electron, and frozen-nuclei approximation of the weak-field asymptotic theory, the rate of tunneling ionization of a molecule in an external static uniform ...electric field is determined by the structure factor for the highest occupied molecular orbital. We present the results of systematic calculations of structure factors for 40 homonuclear and heteronuclear diatomic molecules by the Hartree–Fock method using a numerical grid-based approach implemented in the program X2DHF.
Backgrounds
This study aimed to describe the morbidity and mortality in older patients undergoing laparoscopic radical cystectomy (LRC) and compare the outcomes of LRC between octogenarians and ...younger patients (< 80 years) in a Japanese multicenter cohort.
Methods
We identified 433 patients (80 octogenarians) who underwent LRC in a retrospective multicenter database from 10 institutions. The perioperative outcomes and the 90-day and late (> 90-day) complications according to the Clavien–Dindo classification were compared between the octogenarians and younger patients. Recurrence-free survival (RFS), overall survival (OS), and cancer-specific survival (CSS) were measured by the Kaplan–Meier method.
Results
Compared with the younger group, the octogenarian group included a significantly higher proportion of women, patients with a lower body mass index, patients with a lower preoperative albumin level, and patients with a history of abdominal surgery. The 90-day rates of all complications and major complications (grades III–V) were 50.0% and 20.0% among octogenarians and 54.7% and 16.4% among younger patients. The 90-day mortality rate among octogenarians was 3.8%. The 2-year RFS, CSS, and OS rates for octogenarians stratified by pathological stage was 95.2, 100, and 100% for ≤ pT1; 50.7, 76.6, and 56.1% for pT2; 33.6, 82.5, and 72.6% for ≥ pT3; and 23.1, 42.2, and 37.5% for pN + or distant metastasis, respectively. There was significant difference between octogenarians and younger patients only in 2-year OS for pT2 (56.1% vs 87.7%,
p
= 0.03).
Conclusions
This study revealed that LRC can be performed for selected octogenarians with a complication rate similar to that of younger patients. Appropriate risk evaluation and modification of surgical procedures are necessary for octogenarians.
Background
Although the introduction of multiple agents targeting immune and oncogenic signaling pathways has substantially changed the treatment strategies for urothelial carcinoma (UC), these drugs ...still have some limitations, such as adverse effects and limited responses depending on the molecular subtype of UC. Therefore, the development of novel molecular‐targeted therapies is required. Munc18‐1‐interacting protein 3 (Mint3), which specifically activates hypoxia inducible factor‐1 (HIF‐1) during normoxia in cancer and some stromal cells, might be a good target for UC treatment without severe adverse effects. However, the expression and function of Mint3 in UC remain unclear.
Methods
We prepared bladder cancer (n = 117) and upper tract UC (n = 207) cohorts and analyzed the correlation between Mint3 expression in the tissue microarray and the clinicopathological factors/prognosis. To clarify the function of Mint3 in UC cells, control and Mint3‐depleted UC cells were analyzed for HIF‐1 activity, HIF‐1 target gene expression, cell proliferation, glycolysis, motility and invasion in vitro. Tumorigenicity and angiogenesis in control and Mint3‐depleted UC cells were analyzed in mouse xenograft models. A Mint3 inhibitor, naphthofluorescein and gemcitabine were administrated into UC xenograft‐bearing mice.
Results
Mint3 was expressed at various levels in UC cells; high expression was correlated with a poor prognosis but not with the molecular subtype of UC in two independent UC cohorts. Mint3 depletion did not affect cell proliferation but attenuated HIF‐1 activity, HIF‐1 target gene expression, glycolysis and motility/invasion in both luminal‐ and basal‐molecular‐subtype UC cells in vitro. Mint3 depletion in UC cells also attenuated tumour growth and angiogenesis in xenograft models. In addition, pharmacological inhibition of Mint3 sensitized chemo‐resistant UC xenografts to gemcitabine.
Conclusions
Our findings indicate that Mint3 is a potential target for UC therapy with or without chemotherapy, independent of the molecular subtype of UC.
Graphical Headlights
• Munc18‐1‐interacting protein 3 (Mint3) showed higher expression in urothelial carcinoma (UC) than normal urothelium.
• The expression level of Mint3 correlated with the malignancy of UC.
• Depletion of Mint3 suppressed a progression of UC in vivo.
• Mint3 inhibitor, Naphthofluorescein enhanced anti‐tumour activity of gemcitabine.
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