Equol inhibits growth and spore formation of Clostridioides difficile

AIMS

Equol is a nonsteroidal oestrogen of the isoflavone class. We investigated the antibacterial ability of equol with respect to the growth rate, toxin production and spore-forming abilities of Clostridioides difficile BI/027/NAP1.

METHODS AND RESULTS

Isoflavones, or female hormones, were added to bacterial culture, which was grown at 35°C. The absorbance of the culture was measured at various time points for evaluating the growth inhibition. The toxin levels in the media and morphological changes were also assessed. To evaluate the influence of equol on the sporulation of C. difficile, cells were collected at various time points from the equol-supplemented culture and the number of spores was counted. Our results show that equol inhibits bacterial growth in a concentration-dependent manner. However, it does not inhibit the production of toxin by C. difficile. Other isoflavones and female hormones did not inhibit the C. difficile growth. At the 14th day, approximately 600 spores were present in the control medium and only six were seen in the equol-containing medium.

CONCLUSION

Our results suggest that equol may directly inhibit the C. difficile growth in a concentration-dependent manner and spore formation.

SIGNIFICANCE AND IMPACT OF THE STUDY

This is the first report on the antimicrobial ability of equol.

Pressure-tuning the quantum spin Hamiltonian of the triangular lattice antiferromagnet Cs2CuCl4

Quantum triangular-lattice antiferromagnets are important prototype systems to investigate numerous phenomena of the geometrical frustration in condensed matter. Apart from highly unusual magnetic properties, they possess a rich phase diagram (ranging from an unfrustrated square lattice to a quantum spin liquid), yet to be confirmed experimentally. One major obstacle in this area of research is the lack of materials with appropriate (ideally tuned) magnetic parameters. Using Cs₂CuCl₄ as a model system, we demonstrate an alternative approach, where, instead of the chemical composition, the spin Hamiltonian is altered by hydrostatic pressure. The approach combines high-pressure electron spin resonance and r.f. susceptibility measurements, allowing us not only to quasi-continuously tune the exchange parameters, but also to accurately monitor them. Our experiments indicate a substantial increase of the exchange coupling ratio from 0.3 to 0.42 at a pressure of 1.8 GPa, revealing a number of emergent field-induced phases.

Theoretical studies of quantum magnetism typically assume idealised lattices with freely tunable parameters, which are difficult to realise experimentally. Zvyagin et al. perform challenging measurements at high pressures to tune and to accurately monitor the exchange parameters of a triangular lattice antiferromagnet.

Development and application of 2.5 GPa-25 T high-pressure high-field electron spin resonance system using a cryogen-free superconducting magnet

We have developed a high-pressure electron spin resonance probe and successfully installed into the world's highest-field cryogen-free superconducting magnet having a maximum central field of 24.6 T. The high pressure of 2.5 GPa is achieved by the specially designed piston-cylinder pressure cell using THz-wave-transparent components. In the first application of this high-pressure high-field ESR system, we observed that the orthogonal dimer spin system SrCu₂(BO₃)₂ undergoes a quantum phase transition from the dimer singlet ground to the plaquette singlet ground states.

Ser-Gln sites of SOG1 are rapidly hyperphosphorylated in response to DNA double-strand breaks

The DNA damage response system (DDR) is crucial in addressing DNA double-strand breaks (DSBs), which pose a severe threat to genomic integrity. The SOG1 transcription factor is a master regulator of the Arabidopsis thaliana DDR. We previously showed that hyperphosphorylation of five Ser-Gln sites of SOG1 is the molecular switch to activate the DDR. In this study, we determined that SOG1 is hyperphosphorylated within 20 minutes following DSB-inducing treatment, followed by activation of several SOG1 target genes. Using SOG1 phosphorylation mutants, we demonstrated that although the hyperphosphorylation sites remain unchanged over time, the amount of hyperphosphorylation gradually increases. These observations suggest that rapid SOG1 hyperphosphorylation is limited by the amount of active kinases.

ABBREVIATIONS

SOG1, suppressor of gamma response; ATM, Ataxia telangiectasia mutated; ATR, ATM and Rad3-related.

The effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament reconstruction: An animal study

Objectives

To compare the effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament (ACL) reconstruction animal model.

Methods

Anterior cruciate ligament reconstruction using the plantaris tendon as graft material was performed on both knees of 24 rabbits (48 knees) to mimic ACL reconstruction by two different suspensory fixation devices for graft fixation. For the adjustable fixation device model (Socket group; group S), a 5 mm deep socket was created in the lateral femoral condyle (LFC) of the right knee. For the fixed-loop model (Tunnel group; group T), a femoral tunnel penetrating the LFC was created in the left knee. Animals were sacrificed at four and eight weeks after surgery for histological evaluation and biomechanical testing.

Results

Histologically, both groups showed a mixture of direct and indirect healing patterns at four weeks, whereas only indirect healing patterns were observed in both groups at eight weeks. No significant histological differences were seen between the two groups at four and eight weeks in the roof zone (four weeks, S: mean 4.8 sd 1.7, T: mean 4.5 sd 0.5, p = 0.14; eight weeks, S: mean 5.8 sd 0.8, T: mean 4.8 sd 1.8, p = 0.88, Mann-Whitney U test) or side zone (four weeks, S: mean 5.0 sd 1.2, T: mean 4.8 sd 0.4, p = 0.43; eight weeks, S: mean 5.3 sd 0.8,T: mean 5.5 sd 0.8, p = 0.61, Mann-Whitney U test) . Similarly, no significant difference was seen in the maximum failure load between group S and group T at four (15.6 sd 9.0N and 13.1 sd 5.6N) or eight weeks (12.6 sd 3.6N and 17.1 sd 6.4N, respectively).

Conclusion

Regardless of bone tunnel configuration, tendon-bone healing after ACL reconstruction primarily occurred through indirect healing. No significant histological or mechanical differences were observed between adjustable and fixed-loop femoral cortical suspension methods.

Cite this article: Y. Sato, R. Akagi, Y. Akatsu, Y. Matsuura, S. Takahashi, S. Yamaguchi, T. Enomoto, R. Nakagawa, H. Hoshi, T. Sasaki, S. Kimura, Y. Ogawa, A. Sadamasu, S. Ohtori, T. Sasho. The effect of femoral bone tunnel configuration on tendon-bone healing in an anterior cruciate ligament reconstruction: An animal study. Bone Joint Res 2018;7:327–335. DOI: 10.1302/2046-3758.75.BJR-2017-0238.R2.

First Direct Mass Measurements of Nuclides around Z=100 with a Multireflection Time-of-Flight Mass Spectrograph

The masses of ^{246}Es, ^{251}Fm, and the transfermium nuclei ^{249-252}Md and ^{254}No, produced by hot- and cold-fusion reactions, in the vicinity of the deformed N=152 neutron shell closure, have been directly measured using a multireflection time-of-flight mass spectrograph. The masses of ^{246}Es and ^{249,250,252}Md were measured for the first time. Using the masses of ^{249,250}Md as anchor points for α decay chains, the masses of heavier nuclei, up to ^{261}Bh and ^{266}Mt, were determined. These new masses were compared with theoretical global mass models and demonstrated to be in good agreement with macroscopic-microscopic models in this region. The empirical shell gap parameter δ_{2n} derived from three isotopic masses was updated with the new masses and corroborates the existence of the deformed N=152 neutron shell closure for Md and Lr.

7Be and 8B reaction dynamics at Coulomb barrier energies

We investigated the reaction dynamics induced by the 7Be,8B+208Pb collisions at energies around the Coulomb barrier. Charged particles originated by both the col- lisions were detected by means of 6 ΔE-Eres telescopes of a newly developed detector array. Experimental data were analysed within the framework of the Optical Model and the total reaction cross-sections were compared together and with the 6,7Li+208Pb colli-sion data. According to the preliminary results, 7Be nucleus reactivity is rather similar to the 7Li one whereas the 8B+208Pb total reaction cross section appears to be much larger than those measured for reactions induced by the other weakly-bound projectiles on the same target.

A novel missense mutation affecting the same amino acid as the recurrent PACS1 mutation in Schuurs-Hoeijmakers syndrome

A novel causative variant (c.608G>A, p.Arg203Gln) in PACS1.

The recognition and incidence of peroneal tendon dislocation associated with a fracture of the talus

AIMS

The purposes of this study were to clarify first, the incidence of peroneal tendon dislocation in patients with a fracture of the talus and second the factors associated with peroneal tendon dislocation.

PATIENTS AND METHODS

We retrospectively examined 30 patients (30 ankles) with a mean age of 37.5 years, who had undergone internal fixation for a fracture of the talus. Independent examiners assessed for peroneal tendon dislocation using the pre-operative CT images. The medical records were also reviewed for the presence of peroneal tendon dislocation. The associations between the presence of dislocation with the patient characteristics or radiological findings, including age, mechanism of injury, severity of fracture, and fleck sign, were assessed using Fisher's exact tests.

RESULTS

The pre-operative CT images showed peroneal tendon dislocation in eight out of 30 patients. Dislocation was found later in one patient whose pre-operative CT image had not shown dislocation. The overall incidence of peroneal tendon dislocation was 30% (9/30). The presence of dislocation was associated with the presence of a fleck sign (p = 0.03).

CONCLUSIONS

Surprisingly, approximately one-third of the patients who underwent internal fixation for a fracture of the talus had peroneal tendon dislocation. This was associated with a fleck sign. Cite this article: Bone Joint J 2017;99-B:489-93.