Longer Bread Shelf-Life and Improved Noodle-Making Properties Imparted by a Novel Wheat Genotype Are Stable in Different Genetic Backgrounds

A recently developed wheat variety, known as 5-5 wheat, which has inactive GBSSI-B1, GBSSI-D1, SSIIa-B1, and SSIIa-D1 isozymes, accumulates a novel type of starch, affecting bread texture and leading to reduction in bread staling. These properties are potentially useful for commercial bakery products; thus, the 5-5 genotype represents a new resource for wheat breeding. In this study, the 5-5 alleles were backcrossed into the hard wheat variety "Minaminokaori" and the soft wheat variety "Shirogane-Komugi", which are both leading Japanese wheat varieties. In comparison to their parental varieties, the two 5-5 near-isogenic lines (NILs) showed a decrease in amylose levels, an increase in the proportion of short chains of amylopectin, a lower gelatinization temperature and enthalpy change, a higher peak viscosity and breakdown viscosity as measured by a Rapid Visco Analyzer, a reduced retrogradation rate, and an increase in grain hardness. Importantly, the 5-5 NILs also showed lower bread crumb firmness and reduced hardening after storage for 2 days at either 20 °C or 7 °C. Considering the results obtained here along with those from the original line, it is clear that the 5-5 genotype can generate specific changes in starch characteristics and staling regardless of its genetic background. Thus, we renamed the 5-5 wheat lines "Slow Staling" (SS) wheat. As expected, our results indicated that the hard wheat SS NIL was more suitable for bread-making. On the other hand, we found that white salted noodle made with the SS NIL of the soft wheat variety had a relatively shorter cooking time, a softer texture, and a reduction in textural changes during storage, all of which are potentially useful for noodle manufacturers.

Observation of Coulomb-Assisted Nuclear Bound State of Ξ^{-}-^{14}N System

In an emulsion-counter hybrid experiment performed at J-PARC, a Ξ^{-} absorption event was observed which decayed into twin single-Λ hypernuclei. Kinematic calculations enabled a unique identification of the reaction process as Ξ^{-}+^{14}N→_{Λ}^{10}Be+_{Λ}^{5}He. For the binding energy of the Ξ^{-} hyperon in the Ξ^{-}-^{14}N system a value of 1.27±0.21  MeV was deduced. The energy level of Ξ^{-} is likely a nuclear 1p state which indicates a weak ΞN-ΛΛ coupling.

Pathological assessment of osimertinib-associated cardiotoxicity in EGFR-mutated non-small cell lung cancer patients

Background

Osimertinib, a third-generation epidermal growth factor receptor (EGFR)-tyrosine kinase inhibitor (TKI), inhibits both EGFR-TKI sensitizing mutations and resistant T790M mutations detected in non-small cell lung cancer (NSCLC) patients. Cardiac adverse events (AEs) induced by osimertinib are infrequent; however, cases of severe associated cardiac dysfunction have been reported and remain poorly understood.

Purpose

To assess pathogenesis of osimertinib-associated cardiac AEs, we analyzed myocardial specimens of three NSCLC cases with osimertinib-associated cardiac dysfunction.

Results

Analysis of LVEF prior to and after osimertinb administration in 36 NSCLC patients showed significant decrease of LVEF from 69% to 63%. Within this cohort, right ventricular (RV) biopsy was performed in 2 cases to further understand the pathophysiology of cardiac dysfunction. Case 1 was 78-year-old female with advanced NSCLC harboring an EGFR L858R mutation was treated with osimertinib as second line therapy. After 3 moths of osimetinib treatment, she presented with dyspnea, high NT-proBNP and troponin I, and significantly decreased left ventricular ejection fraction (LVEF) at 28%. RV biopsy showed moderate cardiomyocyte hypertrophy without inflammatory cell infiltration. Case 2 was 52-year-old female with advanced NSCLC harboring L858R mutation. She was treated with osimertinib as first line therapy. After 2 weeks of osimertinib, screening echocardiography revealed a reduction of LVEF from 63% to 41% without cardiac symptom. RV biopsy showed mild cardiomyocyte hypertrophy with infiltration of a few inflammatory cells in interstinum. We further analyzed death case of NSCLC. Case 3 was 63-year-old female with advanced NSCLC harboring EGFR ex. 19 del. and T790M mutations. After 6 months of osimertinib, she suffered from severe respiratory failure and severely reduced LVEF at 27%. She died on the 44th day after admission. Pathological autopsy revealed mild to moderate cardiomyocyte hypertrophy without inflammatory cell infiltration in both ventricles. These pathological findings may indicate neither myocyte injury nor myocarditis was induced by osimertinib in myocardium.

Conclusion

Although additional data collection of advanced NSCLC patients will be important in understanding the pathophysiology of cardiac AEs with osimertinib, osimertinib-associated cardiotoxicity may result from functional inhibition of myocyte contractility by osimertinib without induction of cell death or inflammation.

Funding Acknowledgement

Type of funding source: None

Cost-effectiveness analysis for preventing hepatitis B virus reactivation-related death in Japan

Background

There is no worldwide standard recommendation for preventing hepatitis B virus (HBV) reactivation for patients with resolved infection treated with an anti-CD20 antibody for B-cell non-Hodgkin lymphoma. This study aims to compare the cost-effectiveness between two commonly used strategies to prevent HBV reactivation-related death.

Methods

The two strategies compared were prophylactic antiviral therapy (Pro NAT) and HBV DNA monitoring followed by on-demand antiviral therapy (HBV DNA monitoring) using entecavir (Entecavir, a generic drug for Baraclude). Effectiveness was defined as the prevention of death due to HBV reactivation and costs were calculated under the health insurance system of Japan as of April 2018 using Markov model. A cost-minimization analysis, one of the cost-effectiveness analyses, was applied, since the effectiveness was the same between the two strategies according to a meta-analysis. To consider the effect of uncertainty for each parameter, probabilistic sensitivity analysis (PSA) was performed. In the scenario analysis, costs were calculated using lamivudine (Zefix) or tenofovir alafenamide (Vemlidy) instead of entecavir. All analyses were done using TreeAge Pro 2019 (TreeAge Software, Inc., MA, USA).

Results

Estimated costs per patient during the 30 months after initiation of chemotherapy for lymphoma were 1,513 USD with Pro NAT and 1,265 USD with HBV DNA monitoring. A PSA revealed that HBV DNA monitoring was more consistently cost-effective compared with Pro NAT when some parameters were set randomly according to probability distributions. In our scenario analysis, costs of Pro NAT and HBV DNA monitoring were calculated as 2,762 and 1,401 USD using lamivudine, 4,857 and 1,629 USD using tenofovir alafenamide.

Conclusions

Our cost-effectiveness analysis shows that an HBV DNA monitoring strategy using entecavir should be recommended for preventing HBV reactivation-related death in Japan.

Key messages

Cost-effectiveness analysis demonstrated that HBV DNA monitoring was more cost-effective compared to Pro NAT; this result was consistent with PSA. HBV DNA monitoring strategy should be recommended to prevent HBV reactivation-related death for the patients with resolved HBV infection in Japan.

Bone densitometry worldwide: a global survey by the ISCD and IOF

In a global survey of fracture liaison services, most reported that DXA access met needs. However, adherence to basic DXA quality and reporting procedures was confirmed by only around 50% of institutions and many required education for operators/interpreters. Overall, there is significant variability in the access to, and quality of, DXA services worldwide.

INTRODUCTION

While the use of dual-energy X-ray absorptiometry (DXA) has been widely adopted worldwide for the assessment of bone mineral density, the quality of DXA facilities is unknown. To address this, a global survey of fracture liaison services (FLS) was conducted by the International Society for Clinical Densitometry (ISCD) and the International Osteoporosis Foundation (IOF) to assess the quality of their DXA facilities.

METHODS

A questionnaire for the accessibility and quality of DXA services was co-created by representatives of the ISCD and the IOF and made available to institutions who participated in the Capture the Fracture Best Practice Framework. From a list of 331 contacted invitees, 124 FLS centres responded; analyses were based on 121 centres with suitable data.

RESULTS

Over 70% of institutions reported that, for over 90% of the time, DXA access met service needs, and the scanning/reporting quality was perceived as excellent. However, 25% of DXA facilities reported not being accredited by a professional/governmental organization, and adherence to some basic DXA quality assurance and reporting procedures was confirmed by < 50% of services. Importantly, in excess of 50% of institutions stated that they desired ongoing education in osteoporosis and DXA for operators and interpreters.

CONCLUSION

There is significant variability in the access to and quality of DXA services for established FLS worldwide. Despite two decades of training initiatives in osteoporosis densitometry, many centres are falling short of the standards of the IOF-ISCD Osteoporosis Essentials criteria.

Observation of Magnon Polarization

We measure the mode-resolved direction of the precessional motion of the magnetic order, i.e., magnon polarization, via the chiral term of inelastic polarized neutron scattering spectra. The magnon polarization is a unique and unambiguous signature of magnets and is important in spintronics, affecting thermodynamic properties such as the magnitude and sign of the spin Seebeck effect. However, it has never been directly measured in any material until this work. The observation of both signs of magnon polarization in Y_{3}Fe_{5}O_{12} also gives direct proof of its ferrimagnetic nature. The experiments agree very well with atomistic simulations of the scattering cross section.

A patient-level key performance indicator set to measure the effectiveness of fracture liaison services and guide quality improvement: a position paper of the IOF Capture the Fracture Working Group, National Osteoporosis Foundation and Fragility Fracture Network

The International Osteoporosis Foundation (IOF) Capture the Fracture® Campaign with the Fragility Fracture Network (FFN) and National Osteoporosis Foundation (NOF) has developed eleven patient-level key performance indicators (KPIs) for fracture liaison services (FLSs) to guide quality improvement.

INTRODUCTION

Fracture Liaison Services (FLSs) are recommended worldwide to reduce fracture risk after a sentinel fracture. Given not every FLS is automatically effective, the IOF Capture the Fracture working group has developed and implemented the Best Practice Framework to assess the organisational components of an FLS. We have now developed a complimentary KPI set that extends this assessment of performance to the patient level.

METHODS

The Capture the Fracture working group in collaboration with the Fragility Fracture Network Secondary Fragility Fracture Special Interest Group and National Osteoporosis Foundation adapted existing metrics from the UK-based Fracture Liaison Service Database Audit to develop a patient-level KPI set for FLSs.

RESULTS

Eleven KPIs were selected. The proportion of patients: with non-spinal fractures; with spine fractures (detected clinically and radiologically); assessed for fracture risk within 12 weeks of sentinel fracture; having DXA assessment within 12 weeks of sentinel fracture; having falls risk assessment; recommended anti-osteoporosis medication; commenced of strength and balance exercise intervention within 16 weeks of sentinel fracture; monitored within 16 weeks of sentinel fracture; started anti-osteoporosis medication within 16 weeks of sentinel fracture; prescribed anti-osteoporosis medication 52 weeks after sentinel fracture. The final KPI measures data completeness for each of the other KPIs. For these indicators, levels of achievement were set at the < 50%, 50-80% and > 80% levels except for treatment recommendation where a level of 50% was used.

CONCLUSION

This KPI set compliments the existing Best Practice Framework to support FLSs to examine their own performance using patient-level data. By using this KPI set for local quality improvement cycles, FLSs will be able to efficiently realise the full potential of secondary fracture prevention and improved clinical outcomes for their local populations.

AB0089 THE ANALYSIS FOR THE INHIBITION OF ANGIOGENESIS BY JAK INHIBITOR

Background:

Many blood vessels are generated in the hyperplastic synovial tissue of patients with rheumatoid arthritis (RA), and lead to chronic tissue inflammation and joint destruction [1]. Janus kinase (JAK) family consisting of JAK1, JAK2, JAK3 and tyrosine kinase 2 (TYK2) are chain receptors which phosphorylate signal transducers and activators of transcription (STAT) and mediate inflammatory diseases including RA [2]. Nowadays, several JAK inhibitors such as Tofacitinib (TOF), Baricitinib (BAR) and Peficitinib (PEF) have been developed and demonstrated to have the inhibitory effects on inflammatory arthritis [3-5]. However, there were few reports concerning their effects on angiogenesis in vitro.

Objectives:

The purpose of the present study is to investigate the influence of JAK inhibitors on angiogenesis of human umbilical vein endothelial cell (HUVEC) activated by vascular endothelial growth factor (VEGF).

Methods:

The cell line of HUVECs were used for this study. The activity of proliferation and tube formation were analyzed by counting assay and tube formation assay, respectively.

In counting assay, HUVECs (5 × 104cells/ml) were seeded onto 96-well cell culture plate with 20 ng/ml VEGF including various doses (0.1µM, 1µM, 5µM) of TOF, BAR or PEF. After 48 hours incubation at 37°C in a humidified atmosphere containing 5% CO2, cell proliferation of each groups was assessed using cell counting kit. In tube formation assay, HUVECs (5 × 104cells/ml) were treated with 20ng/ml VEGF including various dose (0.1µM, 1µM, 5µM) of TOF, BAR or PEF for 00 hours, then seeded onto 48-well plate applied with Matrigel. After 24 hours incubation on Matrigel, the capillary-like tube formation of each well was photographed using phase contrast microscopy. Tube formation were quantitated by measurement of the length of branch.

Results:

HUVECs were activated in proliferation and tube formation by VEGF treatment. And, the proliferation and tube formation of HUVECs activated by VEGF were suppressed by All of TOF, BAR and PEF. In particular, TOF and PEF could suppress them highly.

Conclusion:

This study showed the inhibitory effect of JAK inhibitors on proliferation and tube formation of HUVECs activated by VEGF. In particular, the angiogenesis of HUVECs activated by VEGF was highly suppressed by TOF and PEF. VEGF is reported to regulate the angiogenesis through multi JAK-STAT signaling pathways [6]. The inhibitory effects on angiogenesis of TOF, BAR and PEF might depend on the differences in their affinity for JAKs. VEGF has been shown to a have a central involvement in the angiogenic process in RA [7]. JAK inhibitors might suppress the angiogenesis in RA synovial tissues by inhibiting VEGF signaling.

References:

[1]Scott DL, et al. Rheumatoid arthritis. Lancet. 2010.

[2]Banerjee S, et al. JAK-STAT signaling as a target for inflammatory and autoimmune diseases: current and future prospects. Drugs. 2017.

[3]William D, et al. JAK inhibitors in dermatology: the promise of a new drug class. Journal of the American Academy of Dermatology. 2017.

[4]Dhillon S. Tofacitinib: A Review in Rheumatoid Arthritis. Drugs. 2017.

[5]Markham A, et al. Peficitinib: First Global Approval. Drugs. 2019.

[6]Zhang HY, et al. Three important components in the regeneration of the cavernous nerve: brain-derived neurotrophic factor, vascular endothelial growth factor and the JAK/STAT signaling pathway. Asian journal of andrology. 2011.

[7]Paleolog EM. Angiogenesis in rheumatoid arthritis. Arthritis research. 2002.

Acknowledgments:

none

Disclosure of Interests:

None declared

SAT0019 HISTOPATHOLOGICAL CHANGES OF SYNOVIAL TISSUE IN RHEUMATOID ARTHRITIS PATIENTS TREATED WITH TNF INHIBITORS

Background:

Rheumatoid arthritis (RA) is a chronic inflammatory disease characterized by hyperplasia of synovial tissues [1]. Tumor necrosis factor (TNF)-α is one of the pro-inflammatory cytokines that play a crucial role in the pathogenesis of RA synovitis, and TNF inhibitors (TNFi) were reported to force the RA to go into remission or low disease activity and have brought revolutionary impacts on RA treatment [2]. TNFi have been shown to act on inflammatory cells and form the discoid fibrosis in the sublining layers [3,4]. However, the changes of synovial tissue and the cause of discoid fibrosis in RA patients treated with TNFi has not been determined in detail.

Objectives:

The purpose of this study is to demonstrate the histological changes and the types of cells around discoid fibrosis in RA synovium treated with TNFi.

Methods:

Synovial tissues were obtained from 30 patients with RA during joint surgeries. 6 patients were treated with TNFi (1 patient with golimumab, 3 patients with etanercept, 2 patients with infliximab). As a control, synovial tissues were obtained from 6 patients who were treated only with csDMARDs (6 patients with MTX). The frozen sections were stained by hematoxylin and eosin (HE). To detect the apoptosis, TdT-mediated dUTP nick end labeling (TUNEL) was performed. The immunohistochemical characterization of the synovial cells was performed by using following antibodies: CD20 and CD3 for detecting B and T lymphocytes respectively, CD163 and CD86 for detecting M1 and M2 macrophage respectively.

Results:

In the sections stained with HE, the formation of discoid fibrosis and the other characteristic changes including hydropic degeneration, vacuolation, sclerosis of small vasculature, and the number of multilayered synovial cells was decreased in synovium from RA patients treated with TNFi. In the sections with TUNEL stain, apoptosis of lining cells around the discoid fibrosis was detected in RA synovium treated with TNFi (Figure 1a, 1b). In the sections with immunohistochemistry stain, CD86 expression increased in lining layer of RA synovium treated with TNFi. CD163 positive cells showed diffuse expression in RA synovium treated with TNFi. In contrast, CD20 and CD3 positive cells decreased around discoid fibrosis compared to control sections. These results showed indicated that the types of cells in lining and sublining layers were mainly macrophages and that the apoptosis of macrophages might form the discoid fibrosis in lining layers.

Conclusion:

This study showed the apoptosis of lining cells derived from macrophages resulted in the formation of the discoid fibrosis. These findings indicated TNFi might induce apoptosis of macrophage leading to the suppression of RA synovitis.

References:

[1] Scott Dl, et al. Progression of radiological changes in rheumatoid arthritis. Ann Rheum Dis. 1984.

[2]van der Heijde D,et al. Comparison of etanercept and methotrexate, alone and combined, in the treatment of rheumatoid arthritis: two-year clinical and radiographic results from the TEMPO study, a double-blind, randomized trial. Arthritis Rheum. 2006.

[3] Hirohata S,et al. TNF inhibitors induce discoid fibrosis in the sublining layers of the synovium with degeneration of synoviocytes in rheumatoid arthritis. Rheumatol Int. 2013.

[4] Yamanaka H,et al. Scoring evaluation for histopathological features of synovium in patients with rheumatoid arthritis during anti-tumor necrosis factor therapy. Rheumatol Int. 2010.

Acknowledgments :

This research did not receive any specific grant from funding agencies in the public, commercial, or not-for-profit sectors.

Disclosure of Interests:

None declared

Erratum: Publisher Correction: A TonB-dependent receptor constitutes the outer membrane transport system for a lignin-derived aromatic compound

[This corrects the article DOI: 10.1038/s42003-019-0676-z.].

A TonB-dependent receptor constitutes the outer membrane transport system for a lignin-derived aromatic compound

TonB-dependent receptors (TBDRs) mediate substrate-specific transport across the outer membrane, utilizing energy derived from the proton motive force transmitted from the TonB-ExbB-ExbD complex located in the inner membrane (TonB system). Although a number of TonB systems involved in the uptake of siderophores, vitamin B12 and saccharides have been identified, their involvement in the uptake and catabolism of aromatic compounds was previously unknown. Here, we show that the outer membrane transport of a biphenyl compound derived from lignin is mediated by the TonB system in a Gram-negative bacterium capable of degrading lignin-derived aromatic compounds, Sphingobium sp. strain SYK-6. Furthermore, we found that overexpression of the corresponding TBDR gene enhanced the uptake of this biphenyl compound, contributing to the improved rate of platform chemical production. Our results will provide an important basis for establishing engineered strains optimized for use in lignin valorisation.

Study design and protocol for evaluating the long-term prognosis of patients receiving his bundle pacing: A multicenter observational study

BACKGROUND

His bundle pacing (HBP) is a recently developed pacing technique that can achieve an ideal physiological pattern of ventricular activation via stimulation of the native His-Purkinje system. Despite the widespread introduction of HBP in clinical practice, its appropriate indications are yet to be determined clearly. Moreover, the efficacy and safety of HBP and long-term prognosis of patients undergoing such are unknown.

METHODS

We conducted a multicenter observational prospective study in patients undergoing HBP in Japan. Patients with atrioventricular block or conduction delay and estimated ventricular pacing of ≥ 40% scheduled for HBP implantation are included. All patients are followed up until 3 years after the implantation. The primary endpoints are all-cause death, heart failure-related hospitalization, and upgrade to cardiac resynchronization therapy. The secondary endpoint is changes in cardiac function based on echocardiographic findings and laboratory data after the implantation.

RESULTS

The results are currently under investigation.

CONCLUSIONS

This multicenter observational study evaluates the long-term prognosis and changes in cardiac function of patients undergoing HBP implantation in a clinical setting. Considering the large number of patients included, the cumulative results would be helpful in establishing evidence on HBP application in this area and consequently allow accurate management and treatment of patients undergoing HBP.

P1570Cardiac strain detects subclinical decline of cardiac function after hematopoietic stem cell transplantation in patients with hematologic malignancies

Background

Hematopoietic stem cell transplantation (HSCT) has been established as a treatment of various hematologic malignancies and improved their prognoses. HSCT includes intensive chemotherapy and systemic radiation, which occasionally induces cardiac dysfunction. However, early predictor of cardiac dysfunction associated with HSCT is still elusive. Recently, left ventricular (LV) global longitudinal strain (GLS) has been recognized as an early detector of cardiotoxicity. In this study, we retrospectively analyzed GLS and cardiac parameters in patients with hematologic malignancies before and after HSCT to explore HSCT-induced cardiac dysfunction.

Methods

Thirty-one consecutive patients undergone HSCT were enrolled and reviewed their cardiac comorbidities, medications, chemotherapy, and radiotherapy before HSCT. Transthoracic echocardiographic variables including GLS, cardiac troponin-I, and B-type natriuretic peptide were analyzed prior to and 1 month after HSCT.

Results

The patients were 49.7±13.5 years of age, 61% were male, and 52% had cardiovascular risk factors. Cardiac troponin-I was significantly increased following HSCT from 0.010±0.002 ng/ml to 0.016±0.014 ng/ml (P=0.02), indicating that HSCT should have certain impact on cardiac myocytes. Echocardiographic analyses revealed that LV GLS was significantly decreased after HSCT from −19.4±0.8% to −18.8±0.8% (P<0.001), whereas there was no significant difference in LV ejection fraction between these time points of HSCT (63.6±5.5% vs. 64.7±4.6%; P=0.13). Although there was no correlation between the decline of GLS and the increase of troponin-I in this cohort, these results clearly indicated that GLS, but not LVEF, predicted HSCT-induced early and subclinical cardiac dysfunction at 1 month after the HSCT.

Conclusion

GLS detected early decline of cardiac function after HSCT in the patients with hematologic malignancies. Further follow-up investigations will reveal relationship between GLS, troponin-I and prognosis of cardiac function after HSCT in patients with hematologic malignancies.

Diffuse Pulmonary Meningotheliomatosis with Sarcomatous Transformation in a Shiba Dog

A 2-year-old neutered female Shiba dog exhibited laboured breathing for 1 month. Computed tomography of the thoracic cavity revealed multiple nodules (2-5 mm diameter) in the lungs. Grossly, the lungs were firm and normal in shape. The nodules were grey-white in colour. Microscopically, the nodules were non-encapsulated and exhibited an irregular shape. They were composed of polygonal or spindle cells with indistinct cell borders arranged in sheets. The cells had large, round, hyperchromatic nuclei and abundant pale eosinophilic cytoplasm with no atypia. Intrapulmonary arterial emboli and infiltration into the bronchioles were observed. Immunohistochemically, the cells were positive for vimentin and negative for cytokeratin, glial fibrillary acidic protein and α-smooth muscle actin. Ultrastructurally, the cells displayed cytoplasmic processes, desmosomes and intermediate filaments. These findings led to a diagnosis of diffuse pulmonary meningotheliomatosis with sarcomatous transformation. To the best of our knowledge, this is the first report of diffuse pulmonary meningotheliomatosis in a dog.

Observation of two types of charge-density-wave orders in superconducting La2-xSrxCuO4

The discovery of charge- and spin-density-wave (CDW/SDW) orders in superconducting cuprates has altered our perspective on the nature of high-temperature superconductivity (SC). However, it has proven difficult to fully elucidate the relationship between the density wave orders and SC. Here, using resonant soft X-ray scattering, we study the archetypal cuprate La_2-xSr_xCuO₄ (LSCO) over a broad doping range. We reveal the existence of two types of CDW orders in LSCO, namely CDW stripe order and CDW short-range order (SRO). While the CDW-SRO is suppressed by SC, it is partially transformed into the CDW stripe order with developing SDW stripe order near the superconducting T_c. These findings indicate that the stripe orders and SC are inhomogeneously distributed in the superconducting CuO₂ planes of LSCO. This further suggests a new perspective on the putative pair-density-wave order that coexists with SC, SDW, and CDW orders.

To fully elucidate the relationship between density wave orders and superconductivity in high-T_c cuprates remains difficult. Here, the authors reveal two types of charge-density-wave orders and their intertwined relationship with spin-density-wave order and superconductivity in La_2-xSr_xCuO_4.

An Engineered B. subtilis Inducible Promoter System with over 10 000-Fold Dynamic Range

Bacillus subtilis is the leading model Gram-positive bacterium, and a widely used chassis for industrial protein production. However, B. subtilis research is limited by a lack of inducible promoter systems with low leakiness and high dynamic range. Here, we engineer an inducible promoter system based on the T7 RNA Polymerase (T7 RNAP), the lactose repressor LacI, and the chimeric promoter P_T7lac, integrated as a single copy in the B. subtilis genome. In the absence of IPTG, LacI strongly represses T7 RNAP and P_T7lac and minimizes leakiness. Addition of IPTG derepresses P_T7lac and simultaneously induces expression of T7RNAP, which results in very high output expression. Using green fluorescent and β-galactosidase reporter proteins, we estimate that this LacI-T7 system can regulate expression with a dynamic range of over 10 000, by far the largest reported for an inducible B. subtilis promoter system. Furthermore, LacI-T7 responds to similar IPTG concentrations and with similar kinetics as the widely used P_hy-spank IPTG-inducible system, which we show has a dynamic range of at most 300 in a similar genetic context. Due to its superior performance, our LacI-T7 system should have broad applications in fundamental B. subtilis biology studies and biotechnology.

Optogenetic control of Bacillus subtilis gene expression

The Gram-positive bacterium Bacillus subtilis exhibits complex spatial and temporal gene expression signals. Although optogenetic tools are ideal for studying such processes, none has been engineered for this organism. Here, we port a cyanobacterial light sensor pathway comprising the green/red photoreversible two-component system CcaSR, two metabolic enzymes for production of the chromophore phycocyanobilin (PCB), and an output promoter to control transcription of a gene of interest into B. subtilis. Following an initial non-functional design, we optimize expression of pathway genes, enhance PCB production via a translational fusion of the biosynthetic enzymes, engineer a strong chimeric output promoter, and increase dynamic range with a miniaturized photosensor kinase. Our final design exhibits over 70-fold activation and rapid response dynamics, making it well-suited to studying a wide range of gene regulatory processes. In addition, the synthetic biology methods we develop to port this pathway should make B. subtilis easier to engineer in the future.