Molecular identification and characterisation of catalase and catalase-like protein genes in urease-positive thermophilic Campylobacter (UPTC)

BACKGROUND

Thermophilic Campylobacter are important bacterial pathogens of foodborne diseases worldwide. These organisms' physiology requires a microaerophilic atmosphere. To date, little is known about the protective catalase mechanism in urease-positive thermophilic campylobacters (UPTC); hence, it was the aim of this study to identify and characterise catalase and catalase-like protein genes in these organisms.

MATERIALS AND METHODS

Catalase (katA) and catalase (Kat)-like protein genes from the Japanese UPTC CF89-12 strain were molecularly analysed and compared with C. lari RM2100 and other C. lari and thermophilic Campylobacter reference isolates.

RESULTS

A possible open reading frame of 1,422 base pairs, predicted to encode a peptide of 474 amino acid residues, with calculated molecular weight of 52.7 kilo Daltons for katA, was identified within UPTC CF89-12. A probable ribosome binding site, two putative promoters and a putative ρ-independent transcription terminator were also identified within katA. A similar katA cluster also existed in the C. lari RM2100 strain, except that this strain carries no DcuB genes. However, the Kat-like protein gene or any other homologue(s) were never identified in the C. lari RM2100 strain, or in C. jejuni and C. upsaliensis.

CONCLUSIONS

This study demonstrates the presence of catalase/catalase-like protein genes in UPTC organisms. These findings are significant in that they suggest that UPTC organisms have the protective genetic capability of helping protect the organisms from toxic oxygen stress, which may help them to survive in physiologically harsh environments, both within human and animal hosts, as well as in the natural environment.

Quantum Dephasing in a Gated GaAs Triple Quantum Dot due to Nonergodic Noise

We extract the phase coherence of a qubit defined by singlet and triplet electronic states in a gated GaAs triple quantum dot, measuring on time scales much shorter than the decorrelation time of the environmental noise. In this nonergodic regime, we observe that the coherence is boosted and several dephasing times emerge, depending on how the phase stability is extracted. We elucidate their mutual relations, and demonstrate that they reflect the noise short-time dynamics.

Uniaxial stress control of skyrmion phase

Magnetic skyrmions, swirling nanometric spin textures, have been attracting increasing attention by virtue of their potential applications for future memory technology and their emergent electromagnetism. Despite a variety of theoretical proposals oriented towards skyrmion-based electronics (that is, skyrmionics), few experiments have succeeded in creating, deleting and transferring skyrmions, and the manipulation methodologies have thus far remained limited to electric, magnetic and thermal stimuli. Here, we demonstrate a new approach for skyrmion phase control based on a mechanical stress. By continuously scanning uniaxial stress at low temperatures, we can create and annihilate a skyrmion crystal in a prototypical chiral magnet MnSi. The critical stress is merely several tens of MPa, which is easily accessible using the tip of a conventional cantilever. The present results offer a new guideline even for single skyrmion control that requires neither electric nor magnetic biases and consumes extremely little energy.

Chiral magnets can support particle-like magnetization textures called skyrmions which form in lattices and can be manipulated for potential device applications. Here, the authors demonstrate the controlled creation and annihilation of a skyrmion lattice in MnSi single crystals using mechanical stress.

Search for Nucleon and Dinucleon Decays with an Invisible Particle and a Charged Lepton in the Final State at the Super-Kamiokande Experiment

Search results for nucleon decays p→e^{+}X, p→μ^{+}X, n→νγ (where X is an invisible, massless particle) as well as dinucleon decays np→e^{+}ν, np→μ^{+}ν, and np→τ^{+}ν in the Super-Kamiokande experiment are presented. Using single-ring data from an exposure of  273.4  kton·yr, a search for these decays yields a result consistent with no signal. Accordingly, lower limits on the partial lifetimes of τ_{p→e^{+}X}>7.9×10^{32} yr, τ_{p→μ^{+}X}>4.1×10^{32} yr, τ_{n→νγ}>5.5×10^{32} yr, τ_{np→e^{+}ν}>2.6×10^{32}  yr, τ_{np→μ^{+}ν}>2.2×10^{32} yr, and τ_{np→τ^{+}ν}>2.9×10^{31} yr at a 90% confidence level are obtained. Some of these searches are novel.

ABO alleles are linked with haplotypes of an erythroid cell-specific regulatory element in intron 1 with a few exceptions attributable to genetic recombination

Recent investigation of transcriptional regulation of the ABO genes has identified a candidate erythroid cell-specific regulatory element, named the +5·8-kb site, in the first intron of ABO. Six haplotypes of the site have been reported previously. The present genetic population study demonstrated that each haplotype was mostly linked with specific ABO alleles with a few exceptions, possibly as a result of hybrid formation between common ABO alleles. Thus, investigation of these haplotypes could provide a clue to further elucidation of ABO alleles.

Large anisotropic deformation of skyrmions in strained crystal

Mechanical control of magnetism is an important and promising approach in spintronics. To date, strain control has mostly been demonstrated in ferromagnetic structures by exploiting a change in magnetocrystalline anisotropy. It would be desirable to achieve large strain effects on magnetic nanostructures. Here, using in situ Lorentz transmission electron microscopy, we demonstrate that anisotropic strain as small as 0.3% in a chiral magnet of FeGe induces very large deformations in magnetic skyrmions, as well as distortions of the skyrmion crystal lattice on the order of 20%. Skyrmions are stabilized by the Dzyaloshinskii-Moriya interaction, originating from a chiral crystal structure. Our results show that the change in the modulation of the strength of this interaction is amplified by two orders of magnitude with respect to changes in the crystal lattice due to an applied strain. Our findings may provide a mechanism to achieve strain control of topological magnetic structures based on the Dzyaloshinskii-Moriya interaction.

Phase II/III study of second-line chemotherapy comparing irinotecan-alone with S-1 plus irinotecan in advanced gastric cancer refractory to first-line treatment with S-1 (JACCRO GC-05)

BACKGROUND

In Japan, S-1 plus cisplatin has been used as first-line therapy for advanced gastric cancer (AGC). Patients with no response to first-line treatment with S-1 often receive a taxane-alone or irinotecan-alone as second-line treatment. However, second-line treatment with S-1 plus irinotecan is widely used in patients with AGC resistant to first-line S-1-based chemotherapy. The goal of this trial was to determine whether the consecutive use of S-1 plus irinotecan improves survival when compared with irinotecan-alone as second-line treatment for AGC.

PATIENTS AND METHODS

Patients who had disease progression during first-line S-1-based chemotherapy were randomly assigned to receive S-1 plus irinotecan or irinotecan-alone. The S-1 plus irinotecan group received oral S-1 (40-60 mg/m(2)) on days 1-14 and intravenous irinotecan (150 mg/m(2)) on day 1 of a 21-day cycle. The irinotecan-alone group received the same dose of irinotecan intravenously on day 1 of a 14-day cycle. The primary end point was overall survival (OS).

RESULTS

From February 2008 to May 2011, a total of 304 patients were enrolled. The median OS was 8.8 months in the S-1 plus irinotecan group and 9.5 months in the irinotecan-alone group. This difference was not significant (hazard ratio for death, 0.99; 95% confidence interval 0.78-1.25; P = 0.92). Grade 3 or higher toxicities were more common in the S-1 plus irinotecan group than in the irinotecan-alone group.

CONCLUSION

The consecutive use of S-1 plus irinotecan is not recommended as second-line treatment in patients who are refractory to S-1-based first-line chemotherapy. ClinicalTrials.gov ID: NCT00639327.

Comparison of antibiotic susceptibility in viridans group streptococci in low and high antibiotic-prescribing General Practices

WHAT IS KNOWN AND OBJECTIVE

Antibiotic resistance has become a global public health issue. Most antibiotics are prescribed in the community, although there is less stewardship of such agents in the community compared to secondary and tertiary care. Few studies have attempted to examine the prescribing practices in General Practice and its impact on antibiotic resistance and, therefore, a study was performed in order to compare antibiotic susceptibilities of commensal viridans group streptococci (VGS) obtained from patient cohorts in General Practices (GP), who were high and low prescribers of oral antibiotics.

METHOD

Sixty-five patients (<1 month-81 years; 77% female: 23% male) were enrolled onto the study, and viridans group streptococci (n = 5/patient) were collected from each patient's nasal passages and oropharynx region and tested for antibiotic susceptibility against (i) tetracyclines (doxycycline); (ii) macrolides (erythromycin); (iii) β-lactams (penicillin G); and (iv) fluoroquinolones (ofloxacin & levofloxacin).

RESULTS AND DISCUSSION

There were no significant differences in MICs between high and low GP prescribers with doxycycline (P = 0·094), erythromycin (P = 0·122), ofloxacin (P = 0·193) and levofloxacin (P = 0·058). However, there was a significant difference between high and low GP practices with regard to penicillin G (P = 0·031). This finding is important as the β-lactams are the most commonly prescribed oral antibiotic in the community.

WHAT IS NEW AND CONCLUSION

This study demonstrates that high prescribing practices may lead to an altered (higher) level of resistance to these agents in the commensal VGS population, which may be important as reservoirs of antibiotic resistance determinants in subsequent horizontal gene transfer events, particularly with newly colonizing pathogens, including pneumococci. Primary care physicians should be aware that increased prescribing of antibiotics may led to increased level of penicillin resistance.

Fast electrical control of single electron spins in quantum dots with vanishing influence from nuclear spins

We demonstrate fast universal electrical spin manipulation with inhomogeneous magnetic fields. With fast Rabi frequency up to 127 MHz, we leave the conventional regime of strong nuclear-spin influence and observe a spin-flip fidelity >96%, a distinct chevron Rabi pattern in the spectral-time domain, and a spin resonance linewidth limited by the Rabi frequency, not by the dephasing rate. In addition, we establish fast z rotations up to 54 MHz by directly controlling the spin phase. Our findings will significantly facilitate tomography and error correction with electron spins in quantum dots.

Blood group B gene is barely expressed in in vitro erythroid culture of Bm-derived CD34+ cells without an erythroid cell-specific regulatory element

BACKGROUND AND OBJECTIVES

Previously, a weak phenotype Am or Bm was assumed to be caused by a reduction of A or B gene expression in bone marrow cells, but not in mucus-secreting cells. However, ABO expression has not been examined in erythroid progenitor cells of Am or Bm individuals.

MATERIALS AND METHODS

We carried out in vitro erythroid differentiation of CD34(+) cells from peripheral blood of a Bm individual harbouring a 3.0-kb deletion including an erythroid cell-specific regulatory element, named the +5.8-kb site, in intron 1 of the human ABO blood group gene.

RESULTS

During the in vitro differentiation of CD34(+) cells from this Bm individual into erythroid cells, B-antigens were not detectable on the cultured cells by flow cytometric analysis, and allele-specific RT-PCR consistently detected the transcripts from the O allele, but not from the B allele. Moreover, chromatin immunoprecipitation assay demonstrated that both RUNX1 and GATA-2 or GATA-1 were bound to the +5.8-kb site in cultured erythroid cells expressing ABO.

CONCLUSION

It is likely that the +5.8-kb site enhances transcription from the ABO promoter in erythroid cells through binding of RUNX1 and GATA-2 or GATA-1.

High-symmetry polarization domains in low-symmetry ferroelectrics

We present experimental evidence for polygonal domain faceting in the ferroelectric polymer poly(vinylidene fluoride-trifluoroethylene) (PVDF-TrFE) films with the lower orthorhombic crystallographic symmetry. It is proposed that this effect can arise from purely electrostatic depolarizing forces. We show that, in contrast to magnetic bubble shape domains, where such type of deformation instability has a predominantly elliptical character, the emergence of more symmetrical circular harmonics is favored in ferroelectrics with high dielectric constants.

Efficient utilization of EBUS-TBNA samples for both diagnosis and molecular analyses

BACKGROUND

The assessment of an increasing number of molecular markers is becoming a standard requirement from endobronchial ultrasound-guided transbronchial needle aspiration (EBUS-TBNA) specimens. However, it is unclear how many needle passes should be performed and the amount of lung cancer cells that should be sent for molecular analyses. The objective of this study was to determine if it is feasible to divide the material obtained by EBUS-TBNA to allow for molecular analysis without compromising the accuracy of mediastinal staging.

OBJECTIVE

We aimed to determine if dividing EBUS-TBNA specimens has a negative impact on either histopathological diagnosis or molecular analysis.

METHODS

EBUS-TBNA was performed in 249 enlarged lymph nodes. Negative or ambiguous histopathological results were confirmed by surgical means and clinical follow-up over 6 months. The tissue obtained by EBUS-TBNA was placed onto a glass slide and divided for histopathological workup and molecular analysis. The number of passes was recorded. Both the accuracy of the mediastinal lymph node staging and the applicability of the sample division for molecular analysis were assessed.

RESULTS

Each lymph node was punctured an average of 3.18 times and division of the obtained material for diagnosis and molecular analysis was feasible in all cases. The sensitivity and accuracy of the mediastinal lymph node staging were 96.6% and 97.6%, respectively. A cytokeratin (CK)-19-mRNA concentration-based molecular test was feasible in 74.1% of cases.

CONCLUSION

Dividing EBUS-TBNA samples for both histopathological diagnosis and molecular testing is feasible and does not compromise the accuracy of mediastinal staging. This method may be an alternative to taking additional needle passes for molecular analyses.