Search

Abstract DinJ-YafQ is a bacterial type II TA system formed by the toxin RNase YafQ and the antitoxin protein DinJ. The activity of YafQ and DinJ has been rigorously studied in Escherichia coli, but little has been reported about orthologous systems identified in different microorganisms. In this work, we report an in vitro and in vivo functional characterization of YafQ and DinJ identified in two different strains of Lacticaseibacillus paracasei and isolated as recombinant proteins. While DinJ is identical in both strains, the two YafQ orthologs differ only for the D72G substitution in the catalytic site. Both YafQ orthologs digest ribosomal RNA, albeit with different catalytic efficiencies, and their RNase activity is neutralized by DinJ. We further show that DinJ alone or in complex with YafQ can bind cooperatively to a 28-nt inverted repeat overlapping the −35 element of the TA operon promoter. Atomic force microscopy imaging of DinJ-YafQ in complex with DNA harboring the cognate site reveals the formation of different oligomeric states that prevent the binding of RNA polymerase to the promoter. A single amino acid substitution (R13A) within the RHH DNA-binding motif of DinJ is sufficient to abolish DinJ and DinJ-YafQ DNA binding in vitro. In vivo experiments confirm the negative regulation of the TA promoter by DinJ and DinJ-YafQ and unveil an unexpected high expression-related toxicity of the gfp reporter gene. A model for the binding of two YafQ-(DinJ)2-YafQ tetramers to the promoter inverted repeat showing the absence of protein-protein steric clash is also presented. Key points • The RNase activity of L. paracasei YafQ toxin is neutralized by DinJ antitoxin. • DinJ and DinJ-YafQ bind to an inverted repeat to repress their own promoter. • The R13A mutation of DinJ abolishes DNA binding of both DinJ and DinJ-YafQ.

Necrotizing soft tissue infection (NSTI) due to group A Streptococcus (GAS) is a severe life-threatening microbial infection. The administration of adjunct clindamycin has been recommended in the treatment of NSTIs due to GAS. However, robust evidence regarding the clinical benefits of adjunct clindamycin in NSTI patients remains controversial. We aimed to investigate the association between early administration of adjunct clindamycin and in-hospital mortality in patients with NSTI attributed to GAS. The present study was a nationwide retrospective cohort study, using the Japanese Diagnosis Procedure Combination inpatient database focusing on the period between 2010 and 2018. Data was extracted on patients diagnosed with NSTI due to GAS. We compared patients who were administered clindamycin on the day of admission (clindamycin group) with those who were not (control group). A propensity score overlap weighting method was adopted to adjust the unbalanced backgrounds. The primary endpoint was in-hospital mortality and survival at 90 days after admission. We identified 404 eligible patients during the study period. After adjustment, patients in the clindamycin group were not significantly associated with reduced in-hospital mortality (19.2% vs. 17.5%; odds ratio, 1.11; 95% confidence interval, 0.59–2.09; p = 0.74) or improved survival at 90 days after admission (hazard ratio, 0.92; 95% confidence interval, 0.51–1.68; p = 0.80). In this retrospective study, early adjunct clindamycin does not appear to improve survival. Therefore, the present study questions the benefits of clindamycin as an adjunct to broad spectrum antibiotics in patients with NSTI due to GAS.

A polyethylenimine-grafted cellulose monolith was developed for efficient bacterial capture in a continuous flow system. The amino-functionalized monolith showed superior capture capacity for high concentration of both gram-negative (Escherichia coli) and gram-positive (Bacillus subtilis) bacteria compared with the unmodified one. The efficiency and structural stability of the monolith were consistent during bacterial filtering at a high flow velocity. Bacteria were observed to be anchored to the skeleton surface of the monolith. The performance was attributed to the well-interconnected porous structure and strong electrostatic interaction with cells, which endowed the large surface area with retention force allowing for the local adhesion of bacteria in a flow process.

納豆のネバネバの主因であるポリグルタミン酸(PGA)は、枯草菌の一種である納豆菌が分泌生産する高分子です。これまで、PGA生合成に必須なタンパク質は、PGA合成関連pgsオペロンから翻訳されるPgsB、PgsC、およびPgsAと報告されてきました。本研究では、pgsオペロンにおいてpgsAの下流に位置するpgsE遺伝子に着目し、PgsEタンパク質がPGAの生合成に与える影響を動的粘度法や多角度光散乱検出器による分子量解析を通して調べました。その結果、PgsB、PgsC、およびPgsAの3つのタンパク質で生産されたPGAは、ほとんど粘性を示さず、47,000の分子量でした。一方、PgsB、PgsC、PgsA、およびPgsEの4つのタンパク質で生産されたPGAは高粘性を示し、その分子量も2,900,000であることが判明しました。以上の結果より、PgsEは、PGAの分子量を大幅に向上させ、納豆をネバネバにさせる主因である可能性が示唆されました。, Poly(γ-glutamic acid) (PGA) is a biopolymer produced by Bacillus spp. via the γ-amide linkages of D- and/or L-glutamate. Although high-molecular-weight (HMW) PGA possesses many attractive properties, such as flocculating, wound healing, and immune-stimulating effects, no studies have reported factors useful for increasing the molecular weight of PGA during microbial production. PgsB, PgsC, and PgsA are the minimum protein sets required for PGA production in B. subtilis, and PgsE improves PGA productivity. Analysis by size-exclusion chromatography combined with multiangle laser light scattering revealed that the molecular weight of PGA was M_w = 2,900,000 g mol^−1 and predominantly M_w = 47,000 g mol^−1 in preparations derived from B. subtilis cells with and without pgsE, respectively. PgsE may be required to increase the molecular weight of PGA.

More than 31,000 protein-coding sequences (CCDS) have been identified in the human genome. Here, we analyzed codon usage in all human CCDS and found that there is a preferential usage of minor codons for Ala (CGC), Pro (CCG), Ser (UCG), and Thr (ACG) in the initial 50-codon sequences of the CCDS. These codons, with consensus XCG sequences, are most infrequently used among their synonymous codons. Thus, the tRNA concentrations per codon are considered to be highest for the minor codons for Ala, Pro, Ser and Thr in comparison with other synonymous codons for each of them to enhance the translation efficiency. This suggests that human genes are regulated at the level of translation by preferentially using minor codons within the first 50 codons of the CCDS. This hypothesis was experimentally confirmed by comparing the expression of the luciferase gene encoded by minor codons with that encoded by major codons.

Oxygen plasma arc cutting is widely employed in various industrial fields. In the case of cutting magnetized plates, the magnetic field is concentrated around the cutting front as cutting progresses, and the electromagnetic force induced by the leakage of magnetic field deflects the plasma jet. The deflected plasma jet leads to poor cutting quality and sometime causes damage to the electrode and nozzle because of double arc abnormal discharge. This phenomenon is called magnetic arc blow, and it is a critical issue when applying plasma cutting on magnetized plates. In this study, magnetic arc blow behavior is investigated, and a method to prevent it is devised. We examined the relationship between operating conditions and the double arc using external magnetic fields on a plasma jet. We found criteria regarding operation conditions that induce arc blow. In addition, we succeeded in suppressing the double arc caused by the leakage external magnetic field by using a magnetic shield cap composed of ferromagnetic material around the nozzle.

2-(N-Cyanoimino)-5-{(E)-4-styrylbenzylidene}-4-oxothiazolidine (FPFS-410) is a newly synthesized thiazolidine derivative having not only antidiabetic but also lipid-lowering activities. However, this compound has an extremely low aqueous solubility (2.8×10−8 M in phosphate buffer at 25 °C). In this study, we attempted to improve the solubility of FPFS-410 in water, by means of the complexation with 2-hydroxypropyl-β-cyclodextrin (HP-β-CyD). Further, the interaction of FPFS-410 with HP-β-CyD in 50% v/v methanol/water mixed solution was investigated by ultraviolet and 1H-nuclear magnetic resonance (NMR) spectroscopic methods, because the solubility of FPFS-410 in water was too low to study quantitatively the interaction. The results of the solubility method indicated that HP-β-CyD had a markedly high solubilizing ability to FPFS-410, e.g., the solubility of the compound was increased 200,000-fold by the addition of 40 mM HP-β-CyD. The continuous variation plot of the FPFS-410/HP-β-CyD system in 50% v/v methanol/water solution gave a maximum at a host/guest molar ratio of 1:1. 1H-NMR spectroscopic studies suggested that the stilbene moiety of FPFS-410 is preferably included in the HP-β-CyD cavity to form the 1:1 complex in 50% v/v methanol/water solution. The present results suggest that HP-β-CyD is useful for improvement of the oral bioavailability of FPFS-410.

A 21-year-old man was admitted with vomiting and abdominal pain 3 days after sustaining blunt abdominal trauma by being tackled in a game of American football. A diagnosis of intramural hematoma of the duodenum was made using computed tomography and upper gastrointestinal tract contrast radiography. The hematoma caused obstructive jaundice by compressing the common bile duct. The contents of the hematoma were laparoscopically drained. A small perforation was then found in the duodenal wall. The patient underwent laparotomy and repair of the injury. Laparoscopic surgery can be used as definitive therapy in this type of abdominal trauma.

RNA interference mediated by RNA such as antisense RNA, short interfering RNA and micro RNA is well documented to regulate specific gene expression at the level of messenger RNA. However, RNA interference mediated by proteins has not been reported. Here we identify the MazF-hw mRNA interferase from a superhalophilic archaeon that cleaves RNA at a specific seven-base sequence (UUACUCA). This sequence was found unusually abundant in the mRNAs for rhodopsin transcription activator and some membrane proteins of the archaeon, suggesting that the expression of these proteins is regulated by MazF-hw. When all of the seven-base cleavage sites in essential genes in Escherichia coli were eliminated, the cells were no longer sensitive to MazF-hw, demonstrating that specific gene expression can be regulated by a sequence-specific mRNA interferase. These findings demonstrate that mRNA interference can be mediated not only by RNA but also by proteins to effectively silence specific gene expression in cells.

A new mechanism of heteroclinic tangency is investigated by using two-dimensional maps. First, it is numerically shown that the unstable manifold from a hyperbolic fixed point accumulates to the stable manifold of a nearby period-2 hyperbolic point in a piecewise linear map and that the unstable manifold from a hyperbolic fixed point accumulates to the accumulation of the stable manifold of a nearby period-2 hyperbolic point in a cubic map. Second, a theorem on the impossibility of heteroclinic tangency (in the usual sense) is given for a particular type of map. The notions ofdirect andasymptotic heteroclinic tangencies are introduced and heteroclinic tangency is classified into four types.

Spherical particles with diameters of 2-5 μm are prepared from partially aminated poly(L-glutamic acid) by coacervation. They are shown to be excellent carriers for immunoassay, showing high sensitivity and a lack of non-specific agglutination.

Using the properties of the Jordan curve, the following theorem on the heteroclinic tangency in orientation-preserving two-dimensional maps is proved: LetT μ :R 2 →R 2 be a one-parameter family ofC 1 diffeomorphisms andJ=DetDT μ be such that 0μ c ,W andW s/m have a transversal heteroclinic point. Then atμ=μ c ,W andW are in the first asymptotic heteroclinic tangency except for the following three cases: (1)n=m; both cycles are without reflection. (2)m=2n; then- andm-cycles are with and without reflection, respectively; (3)n=2m; then- andm-cycles are without and with reflection, respectively.

Improvement of photovoltaic performance for dye sensitized solar cells (DSC) is discussed in terms of electron-path and ion-path. In order to make electron path, we focused on passivation of TiO2 surface states which are observed by thermally stimulated current (TSC). The TiO2 surface was well-passivated with dye molecules under pressurized CO2 atmosphere. It was found that DSC cells prepared by a CO2 process (Cell-CO2) had higher efficiency than those prepared by a conventional dipping process (Cell-DIP) and the higher efficiency was associated with low TiO2-surface state, high electron diffusion coefficient and long electron life time in TiO2 for the Cell-CO2. In addition, dye-staining under pressurized CO2 atmosphere had advantages over a conventional dipping process on rapid dye-uptake and less dye aggregation. In order to fabricate ion-path in solidified electrolyte, we focused on surface modification of nano-materials. Surface of nano-materials such as TiO2-nanoparticles and porous alumina films were modified with imidazolium iodide moieties consisting of long alkyl chains which render surface-molecules self-organized. Redox-species are concentrated on the self-organized molecules and make ion-path. We propose quasi-solid electrolyte system consisting of two layers having different charge carrier concentration to keep high photoconversion efficiencies even after solidification.

A direction to increasing photovoltaic performances of dye sensitized solar cells (DSC) is proposed. An interface between TiO2/dye and an electrolyte layer is focused on. It is proved that better coverage of TiO2layers with dye molecules increases photovoltaic performances, where dye staining is carried out in pressurized CO2atmosphere. This is explained by decreases in the amount of surface traps on TiO2nano-particles, which is discussed by thermally stimulated current (TSC). The decrease in the surface trap density increases electron diffusion coefficient and improves electron lifetime in TiO2layers. In addition, the TiO2-staining with dye molecules having the larger dipole moment seems to leave less amount of electron trap. Another crucial research item is solidification. Quasi-solidification is carried out by using surface modified anodically-oxidized Al2O3films filled with ionic liquids, where ion paths are fabricated on the surface-modified Al2O3walls by concentrating iodine and iodide molecules on the walls. Because of the fabrication of the ion path, photovoltaic performances increased even after solidification. Grötthuss type mechanism is introduced to explain the increase in the photovoltaic performances after the solidification.

To validate the Japanese Association for Acute Medicine (JAAM) disseminated intravascular coagulation (DIC) scoring system in patients with severe sepsis, we conducted a multicenter, prospective study at 15 critical care centers in tertiary care hospitals. This study included 624 severe sepsis patients. JAAM DIC was scored on the day of diagnosis of severe sepsis (day 1) and day 4. Scores for disease severity and organ dysfunction were also evaluated. The prevalence of JAAM DIC was 46.8% (292/624), and 21% of the DIC patients were scored according to the reduction rate of platelets. The JAAM DIC patients were more seriously ill and exhibited more severe systemic inflammation, a higher prevalence of multiple organ dysfunction syndrome (MODS) and worse outcomes than the non-DIC patients. Disease severity, systemic inflammation, MODS and the mortality rate worsened in accordance with an increased JAAM DIC score on day 1. The Kaplan-Meier curves demonstrated lower 1-year survival in the JAAM DIC patients than in those without DIC (log-rank test P