RNA-binding protein Hfq downregulates locus of enterocyte effacement-encoded regulators independent of small regulatory RNA in enterohemorrhagic Escherichia coli.

Enterohemorrhagic Escherichia coli (EHEC) causes severe human diseases worldwide. The type 3 secretion system and effector proteins are essential for EHEC infection, and are encoded by the locus of enterocyte effacement (LEE). RNA-binding protein Hfq is essential for small regulatory RNA (sRNA)-mediated regulation at a posttranscriptional level and full virulence of many pathogenic bacteria. Although two early studies indicated that Hfq represses LEE expression by posttranscriptionally controlling the expression of genes grlRA and/or ler, both of which encode LEE regulators mediating a positive regulatory loop, the detailed molecular mechanism and biological significance remain unclear. Herein, we show that LEE overexpression was caused by defective RNA-binding activity of the Hfq distal face, which posttranscriptionally represses grlA and ler expression. In vitro analyses revealed that the Hfq distal face directly binds near the translational initiation site of grlA and ler mRNAs, and inhibits their translation. Taken together, we conclude that Hfq inhibits grlA and ler translation by binding their mRNAs through the distal face in an sRNA-independent manner. Additionally, we show that Hfq-mediated repression of LEE is critical for normal EHEC growth because all suppressor mutations that restored the growth defect in the hfq mutant abolished hfq deletion-induced overexpression of LEE.

uvrY Deletion and Acetate Reduce Gut Colonization of Crohn's Disease-Associated Adherent-Invasive Escherichia coli by Decreasing Expression of Type 1 Fimbriae.

Adherent-invasive Escherichia coli (AIEC) is involved in onset and/or exacerbation of Crohn's disease (CD). AIEC adapts to the gut environment by altering gene expression programs, leading to successful gut-lumen colonization. However, the underlying mechanism of gut colonization is still far from clarified. Here, we show the role of UvrY, a response regulator of bacterial two-component signal transduction systems, in AIEC gut colonization. An AIEC mutant lacking the uvrY gene exhibited impairment of competitive colonization in the murine intestinal tract. UvrY contributes to functional expression of type 1 fimbriae by activating expression of small RNA CsrB, which confers adherence and invasion into epithelial cells on AIEC. In contrast, acetate suppresses the UvrY-dependent expression of type 1 fimbriae, resulting in less efficient cell invasion and attenuated gut colonization. Our findings might lead to therapeutic interventions for CD, in which inhibitions of UvrY activation and acetate supplementation reduce the colonization levels of AIEC by decreasing type 1 fimbria expression.

Fatty Acid Homeostasis Tunes Flagellar Motility by Activating Phase 2 Flagellin Expression, Contributing to Salmonella Gut Colonization.

Long-chain-fatty-acid (LCFA) metabolism is a fundamental cellular process in bacteria that is involved in lipid homeostasis, energy production, and infection. However, the role of LCFA metabolism in Salmonella enterica serovar Typhimurium (S. Tm) gut infection remains unclear. Here, using a murine gastroenteritis infection model, we demonstrate involvement of LCFA metabolism in S. Tm gut colonization. The LCFA metabolism-associated transcriptional regulator FadR contributes to S. Tm gut colonization. fadR deletion alters the gene expression profile and leads to aberrant flagellar motility of S. Tm. Colonization defects in the fadR mutant are attributable to altered swimming behavior characterized by less frequently smooth swimming, resulting from reduced expression of the phase 2 flagellin FljB. Notably, changes in lipid LCFA composition by fadR deletion lead to reduced expression of fljB, which is restored by exogenous LCFA. Therefore, LCFA homeostasis may maintain proper flagellar motility by activating fljB expression, contributing to S. Tm gut colonization. Our findings improve the understanding of the effect of luminal LCFA on the virulence of enteric pathogens.

Small RNA Esr41 inversely regulates expression of LEE and flagellar genes in enterohaemorrhagic Escherichia coli.

Enterohaemorrhagic Escherichia coli (EHEC) is a life-threatening human pathogen worldwide. The locus of enterocyte effacement (LEE) in EHEC encodes a type three secretion system and effector proteins, all of which are essential for bacterial adherence to host cells. When LEE expression is activated, flagellar gene expression is down-regulated because bacterial flagella induce the immune responses of host cells at the infection stage. Therefore, this inverse regulation is also important for EHEC infection. We report here that a small regulatory RNA (sRNA), Esr41, mediates LEE repression and flagellar gene activation. Multiple copies of esr41 abolished LEE expression by down-regulating the expression of ler and pch, which encode positive regulators of LEE. This regulation led to reduced EHEC adhesion to host cells. Translational gene-reporter fusion experiments revealed that Esr41 regulates ler expression at a post-transcriptional level, and pch transcription, probably via an unknown target of Esr41. Esr41-mediated ler and pch repression was not observed in cells lacking hfq, which encodes an RNA-binding protein essential for most sRNA functions, indicating that Esr41 acts in an Hfq-dependent manner. We previously reported an increase in cell motility induced by Esr41. This motility enhancement was also observed in EHEC lacking ler, showing that Esr41-mediated enhancement of cell motility is in a ler-independent manner. In addition, Esr41 activated the expression of flagellar Class 3 genes by indirectly inducing the transcription of fliA, which encodes the sigma factor for flagellar synthesis. These results suggest that Esr41 plays important roles in the inverse regulation of LEE and flagellar gene expression.

Rattractor-Instant guidance of a rat into a virtual cage using the deep brain stimulation.

We developed "Rattractor" (rat attractor), a system to apply electrical stimuli to the deep brain of a rat as it stays in a specified region or a virtual cage to demonstrate an instant electrophysiological feedback guidance for animals. Two wire electrodes were implanted in the brains of nine rats. The electrodes targeted the medial forebrain bundle (MFB), which is a part of the reward system in the deep brain. Following the recovery period, the rats were placed in a plain field where they could move freely, but wired to a stimulation circuit. An image sensor installed over the field detected the subject's position, which triggered the stimulator such that the rat remained within the virtual cage. We conducted a behavioral experiment to evaluate the sojourn ratio of rats residing in the region. Thereafter, a histological analysis of the rat brain was performed to confirm the position of the stimulation sites in the brain. Seven rats survived the surgery and the recovery period without technical failures such as connector breaks. We observed that three of them tended to stay in the virtual cage during stimulation, and this effect was maintained for two weeks. Histological analysis revealed that the electrode tips were correctly placed in the MFB region of the rats. The other four subjects showed no apparent preference for the virtual cage. In these rats, we did not find electrode tips in the MFB, or could not determine their positions. Almost half of the rats tended to remain inside the virtual cage when position-related reward stimuli were triggered in the MFB region. Notably, our system did not require previous training or sequential interventions to affect the behavioral preferences of subjects. This process is similar to the situation in which sheep are chased by a shepherd dog in the desired direction.

The positive and negative effects of the COVID-19 pandemic on subjective well-being and changes in social inequality: Evidence from prefectures in Japan.

This study aims to specify the effects of the COVID-19 pandemic on individual subjective well-being in Japan and to clarify the mechanism generating social inequality of subjective well-being during the crisis. Data were analyzed using fixed effects ordinary least squares (OLS) regression models from the Online Panel Survey of Social Stratification and Psychology in 2020 (SSPW2020-Panel), which was conducted in four waves in June 2020, September 2020, December 2020, and March 2021. The results reveal that COVID-19 spread in a prefecture had differential effects on subjective well-being in prefectures with high infection rates: positive effects for socially advantaged individuals and negative effects for socially disadvantaged individuals. In conclusion, social inequality in Japan, in terms of subjective well-being, has been widened by the COVID-19 pandemic during 2020.

Lysogenisation of Shiga toxin-encoding bacteriophage represses cell motility.

Bacteriophages are genetic elements that play key roles in the evolution and diversification of bacterial genomes. The Shiga toxin (Stx)-encoding phage plays an important role in the horizontal transfer of the stx gene. However, the influence of the Stx phage integration on the physiological properties and gene expression pattern of the host have not been clearly resolved. In this study, we constructed the Sp5 lysogen through lysogenisation of E. coli K-12 by Sp5, an Stx2 phage in enterohaemorrhagic E. coli (EHEC) O157:H7 Sakai, and examined the effect of the resulting lysogen on cell motility under various growth conditions. Sp5 lysogenisation decreased cell motility and the expression of fliC, which encodes flagellin, under anaerobic conditions at 37°C. Sp5 also lowered the expression of fliA, which encodes the FliA-sigma factor responsible for the transcription of fliC, and flhD, which facilitates the expression of fliA. Sp5 lysogenisation reduced the amount of FlhD and FlhC expressed from the araBAD promoter, suggesting that one or more genes present in Sp5 represses flhDC at the post-transcriptional level. Flagellin is highly antigenic and triggers an immune response in the host. Thus, Sp5 might enhance its viability by repressing the expression of the flagellar regulon to circumvent the immune response of host cells.

[A CASE REPORT OF PRIMARY MUCOSA ASSOCIATED LYMPHOID TISSUE LYMPHOMA OF THE PROSTATE].

The patient was a 53-year-old man who was referred to the department of urology of our hospital after screening results indicated elevated prostate-specific antigen (PSA) levels. The PSA level was 5.33 ng/ml, and rectal examination revealed that the prostate was elastic and hard with mild prostatic hyperplasia. Because magnetic resonance imaging revealed abnormal signals in the prostatic transition area, prostate cancer was suspected and the patient underwent transrectal prostate needle biopsy. The pathological diagnosis was adenocarcinoma (Gleason score 5+5 = 10). After using thoracic, abdominal, and pelvic computed tomography (CT) and bone scintigraphy to confirm that metastasis had not occurred, robot-assisted radical prostatectomy (RARP) was performed. Prostate cancer was not detected during pathologic diagnosis of the surgical specimen, and on the basis of the results of re-examination with immunostaining, a diagnosis of mucosa-associated lymphoid tissue (MALT) lymphoma was made. In addition, an upper and lower endoscopy examination, positron emission tomography (PET) -CT, and bone marrow biopsy confirmed that generalized tumor lesions and lymph node swelling were not present, and the patient was diagnosed with primary MALT lymphoma of the prostate. Currently, 12 months since surgery, the patient continues to undergo follow-up as an outpatient and no recurrence has been observed. There have been only a few reports of primary MALT lymphoma of the prostate, in English or Japanese, and herein, we present our experience with a patient for whom a definitive diagnosis was difficult, along with a review of the literature.

A novel small regulatory RNA enhances cell motility in enterohemorrhagic Escherichia coli.

Small regulatory RNAs (sRNAs) are conserved among a wide range of bacteria. They modulate the translational efficiency of target mRNAs through base-pairing with the help of RNA chaperone Hfq. The present study identified a novel sRNA, Esr41 (enterohemorrhagic Escherichia coli O157 small RNA #41), from an intergenic region of an enterohemorrhagic E. coli (EHEC) O157:H7 Sakai-specific sequence that is not present in the nonpathogenic E. coli K-12. Esr41 was detected as an RNA molecule approximately 70 nucleotides long with a 3' GC-rich palindrome sequence followed by a long poly(U), which is a characteristic of rho-independent terminators and is also a structural feature required for the action of Hfq. EHEC O157 harboring a multicopy plasmid carrying the esr41 gene increased cell motility and the expression of fliC, a gene encoding a major flagellar component. These results indicate that Esr41 stimulates fliC expression in EHEC O157. Furthermore, the increase in cell motility induced by Esr41 was also observed in the E. coli K-12, suggesting that target genes controlled by Esr41 are present in both EHEC O157 and K-12.

Bilateral testicular tumors in an infertile man previously treated with follicle-stimulating hormones.

A 43-year-old infertile man with oligozoospermia and normal serum gonadotropin and cytogenetic findings was treated with follicle-stimulating hormone for 1 year at our institution. Two years later, the patient presented with bilateral palpable testicular tumors. His beta-human chorionic gonadotropin and lactate dehydrogenase levels were elevated. Pathologic examination disclosed a pure seminoma in each testis (pT1N0M0). Adjuvant radiotherapy was administered. The tumors might have been induced by follicle-stimulating hormone treatment. Careful follow-up examination of the testis is necessary in men who have received hormonal treatment for infertility.