Surface-Diffusion-Induced Amorphization of Pt Nanoparticles over Ru Oxide Boost Acidic Oxygen Evolution.

Phase transformation offers an alternative strategy for the synthesis of nanomaterials with unconventional phases, allowing us to further explore their unique properties and promising applications. Herein, we first observed the amorphization of Pt nanoparticles on the RuO2 surface by in situ scanning transmission electron microscopy. Density functional theory calculations demonstrate the low energy barrier and thermodynamic driving force for Pt atoms transferring from the Pt cluster to the RuO2 surface to form amorphous Pt. Remarkably, the as-synthesized amorphous Pt/RuO2 exhibits 14.2 times enhanced mass activity compared to commercial RuO2 catalysts for the oxygen evolution reaction (OER). Water electrolyzer with amorphous Pt/RuO2 achieves 1.0 A cm-2 at 1.70 V and remains stable at 200 mA cm-2 for over 80 h. The amorphous Pt layer not only optimized the *O binding but also enhanced the antioxidation ability of amorphous Pt/RuO2, thereby boosting the activity and stability for the OER.

A P-type pentatricopeptide repeat protein ZmRF5 promotes 5' region partial cleavages of atp6c transcripts to restore the fertility of CMS-C maize by recruiting a splicing factor.

A fast evolution within mitochondria genome(s) often generates discords between nuclear and mitochondria, which is manifested as cytoplasmic male sterility (CMS) and fertility restoration (Rf) system. The maize CMS-C trait is regulated by the chimeric mitochondrial gene, atp6c, and can be recovered by the restorer gene ZmRf5. Through positional cloning in this study, we identified the nuclear restorer gene, ZmRf5, which encodes a P-type pentatricopeptide repeat (PPR) family protein. The over-expression of ZmRf5 brought back the fertility to CMS-C plants, whereas its genomic editing by CRISPR/Cas9 induced abortive pollens in the restorer line. ZmRF5 is sorted to mitochondria, and recruited RS31A, a splicing factor, through MORF8 to form a cleaving/restoring complex, which promoted the cleaving of the CMS-associated transcripts atp6c by shifting the major cleavage site from 480th nt to 344 th nt for fast degradation, and preserved just right amount of atp6c RNA for protein translation, providing adequate ATP6C to assembly complex V, thus restoring male fertility. Interestingly, ATP6C in the sterile line CMo17A, with similar cytology and physiology changes to YU87-1A, was accumulated much less than it in NMo17B, exhibiting a contrary trend in the YU87-1 nuclear genome previously reported, and was restored to normal level in the presence of ZmRF5. Collectively these findings unveil a new molecular mechanism underlying fertility restoration by which ZmRF5 cooperates with MORF8 and RS31A to restore CMS-C fertility in maize, complemented and perfected the sterility mechanism, and enrich the perspectives on communications between nucleus and mitochondria.

Bioinformatics analysis and function prediction of NBS-LRR gene family in Broussonetia papyrifera.

Most of the currently available disease resistance (R) genes have NBS (nucleotide-binding site) and LRR (leucine-rich-repeat) domain which belongs to the NBS-LRR gene family. The whole genome sequencing of Broussonetia papyrifera provides an important bioinformatics database for the study of the NBS-LRR gene family. In this study, 328 NBS-LRR family genes were identified and classified in B. papyrifera according to different classification schemes, where there are 92 N types, 47 CN type, 54 CNL type, 29 NL types, 55 TN type, and 51 TNL type. Subsequently, we conducted bioinformatics analysis of the NBS-LRR gene family. Classification, motif analysis of protein sequences, and phylogenetic tree studies of the NBS-LRR genes in B. papyrifera provide important basis for the functional study of NBS-LRR family genes. Additionally, we performed structural analysis of the chromosomal location, physicochemical properties, and sequences identified by genetic characterization. In addition, through the analysis of GO enrichment, it was found that NBS-LRR genes were involved in defense responses and were significantly enriched in biological stimulation, immune response, and abiotic stress. In addition, we found that Bp06g0955 was the most sensitive to low temperature and encoded the RPM1 protein by analyzing the low temperature transcriptome data of B. papyrifera. Quantitative results of gene expression after 48 h of Fusarium infection showed that Bp01g3293 increased 14 times after infection, which encodes RPM1 protein. The potential of NBS-LRR gene responsive to biotic and abiotic stresses can be exploited to improve the resistance of B. papyrifera.

Cooperative Ni(Co)-Ru-P Sites Activate Dehydrogenation for Hydrazine Oxidation Assisting Self-powered H2 Production.

Water electrolysis for H2 production is restricted by the sluggish oxygen evolution reaction (OER). Using the thermodynamically more favorable hydrazine oxidation reaction (HzOR) to replace OER has attracted ever-growing attention. Herein, we report a twisted NiCoP nanowire array immobilized with Ru single atoms (Ru1 -NiCoP) as superior bifunctional electrocatalyst toward both HzOR and hydrogen evolution reaction (HER), realizing an ultralow working potential of -60 mV and overpotential of 32 mV for a current density of 10 mA cm-2 , respectively. Inspiringly, two-electrode electrolyzer based on overall hydrazine splitting (OHzS) demonstrates outstanding activity with a record-high current density of 522 mA cm-2 at cell voltage of 0.3 V. DFT calculations elucidate the cooperative Ni(Co)-Ru-P sites in Ru1 -NiCoP optimize H* adsorption, and enhance adsorption of *N2 H2 to significantly lower the energy barrier for hydrazine dehydrogenation. Moreover, a self-powered H2 production system utilizing OHzS device driven by direct hydrazine fuel cell (DHzFC) achieve a satisfactory rate of 24.0 mol h-1 m-2 .

The superposition effects of air pollution on government health expenditure in China- spatial evidence from GeoDetector.

BACKGROUND: As the fifth-largest global mortality risk factor, air pollution has caused nearly one-tenth of the world's deaths, with a death toll of 5 million. 21% of China's disease burden was related to environmental pollution, which is 8% higher than the US. Air pollution will increase the demand and utilisation of Chinese residents' health services, thereby placing a greater economic burden on the government. This study reveals the spatial impact of socioeconomic, health, policy and population factors combined with environmental factors on government health expenditure. METHODS: Spearman's correlation coefficient and GeoDetector were used to identify the determinants of government health expenditure. The GeoDetector consist of four detectors: factor detection, interaction detection, risk detection, and ecological detection. One hundred sixty-nine prefecture-level cities in China are studied. The data sources are the 2017 data from China's Economic and Social Big Data Research Platform and WorldPOP gridded population datasets. RESULTS: It is found that industrial sulfur dioxide attributed to government health expenditure, whose q value (explanatory power of X to Y) is 0.5283. The interaction between air pollution factors and other factors will increase the impact on government health expenditure, the interaction value (explanatory power of × 1âˆ©× 2 to Y) of GDP and industrial sulfur dioxide the largest, whose values is 0.9593. There are 96 simple high-risk areas in these 169 areas, but there are still high-risk areas affected by multiple factors. CONCLUSION: First, multiple factors influence the spatial heterogeneity of government health expenditure. Second, health and socio-economic factors are still the dominant factors leading to increased government health expenditure. Third, air pollution does have an important impact on government health expenditure. As a catalytic factor, combining with other factors, it will strengthen their impact on government health expenditure. Finally, an integrated approach should be adopted to synergisticly governance the high-risk areas with multi-risk factors.

Identification and Investigation of the Genetic Variations and Candidate Genes Responsible for Seed Weight via GWAS in Paper Mulberry.

Seeds directly determine the survival and population size of woody plants, but the genetic basis of seed weight in woody plants remain poorly explored. To identify genetic variations and candidate genes responsible for seed weight in natural woody populations, we investigated the hundred-seed weight of 198 paper mulberry individuals from different areas. Our results showed that the hundred-seed weight of paper mulberry was significantly associated with the bioclimatic variables of sampling sites, which increased from south to north along the latitudinal-temperature gradient. Using 2,414,978 high-quality SNPs from re-sequencing data, the genome-wide association analysis of the hundred-seed weight was performed under three models, which identified 148, 19 and 12 associated genes, respectively. Among them, 25 candidate genes were directly hit by the significant SNPs, including the WRKY transcription factor, fatty acid desaturase, F-box protein, etc. Most importantly, we identified three crucial genetic variations in the coding regions of candidate genes (Bp02g2123, Bp01g3291 and Bp10g1642), and significant differences in the hundred-seed weight were detected among the individuals carrying different genotypes. Further analysis revealed that Bp02g2123 encoding a fatty acid desaturase (FAD) might be a key factor affecting the seed weight and local climate adaptation of woody plants. Furthermore, the genome-wide investigation and expression analysis of FAD genes were performed, and the results suggested that BpFADs widely expressed in various tissues and responded to multiple phytohormone and stress treatments. Overall, our study identifies valuable genetic variations and candidate genes, and provides a better understanding of the genetic basis of seed weight in woody plants.

Natural population re-sequencing detects the genetic basis of local adaptation to low temperature in a woody plant.

KEY MESSAGE: Total of 14 SNPs associated with overwintering-related traits and 75 selective regions were detected. Important candidate genes were identified and a possible network of cold-stress responses in woody plants was proposed. Local adaptation to low temperature is essential for woody plants to against changeable climate and safely survive the winter. To uncover the specific molecular mechanism of low temperature adaptation in woody plants, we sequenced 134 core individuals selected from 494 paper mulberry (Broussonetia papyrifera), which naturally distributed in different climate zones and latitudes. The population structure analysis, PCA analysis and neighbor-joining tree analysis indicated that the individuals were classified into three clusters, which showed forceful geographic distribution patterns because of the adaptation to local climate. Using two overwintering phenotypic data collected at high latitudes of 40°N and one bioclimatic variable, genome-phenotype and genome-environment associations, and genome-wide scans were performed. We detected 75 selective regions which possibly undergone temperature selection and identified 14 trait-associated SNPs that corresponded to 16 candidate genes (including LRR-RLK, PP2A, BCS1, etc.). Meanwhile, low temperature adaptation was also supported by other three trait-associated SNPs which exhibiting significant differences in overwintering traits between alleles within three geographic groups. To sum up, a possible network of cold signal perception and responses in woody plants were proposed, including important genes that have been confirmed in previous studies while others could be key potential candidates of woody plants. Overall, our results highlighted the specific and complex molecular mechanism of low temperature adaptation and overwintering of woody plants.

Zidovudine enhances activity of carbapenems against NDM-1-producing Enterobacteriaceae.

OBJECTIVES: To investigate the efficacy of zidovudine in combination with carbapenems against NDM-1-producing Enterobacteriaceae. METHODS: MICs were determined using the broth microdilution method. The combinatory effects of zidovudine and carbapenems were examined using the chequerboard method and time-kill analysis. RESULTS: We found that the NDM-1-producing strains were resistant to all carbapenems tested. FIC index from chequerboard assay demonstrated that zidovudine synergized with carbapenems against all the NDM-1 strains. Time-kill analysis demonstrated significant synergistic activity when a low level of zidovudine was combined with meropenem. CONCLUSIONS: Zidovudine in combination with carbapenems produced synergistic activity against NDM-1 Enterobacteriaceae strains in vitro.

Coplanar Pt/C Nanomeshes with Ultrastable Oxygen Reduction Performance in Fuel Cells.

Developing highly stable and efficient catalysts toward the oxygen reduction reaction is important for the long-term operation in proton exchange membrane fuel cells. Reported herein is a facile synthesis of two-dimensional coplanar Pt-carbon nanomeshes (NMs) that are composed of highly distorted Pt networks (neck width of 2.05±0.72 nm) and carbon. X-ray absorption fine structure spectroscopy demonstrated the metallic state of Pt in the coplanar Pt/C NMs. Fuel cell tests verified the excellent activity of the coplanar Pt/C NM catalyst with the peak power density of 1.21 W cm-2 and current density of 0.360 A cm-2 at 0.80 V in the H2 /O2 cell. Moreover, the coplanar Pt/C NM electrocatalysts showed superior stability against aggregation, with NM structures preserved intact for a long-term operation of over 30 000 cycles for electrode measurement, and the working voltage loss was negligible after 120 h in the H2 /O2 single cell operation. Density-functional theory analysis indicates the increased vacancy formation energy of Pt atoms for coplanar Pt/C NMs, restraining the tendency of Pt dissolution and aggregation.

Cooperation between Broussonetia papyrifera and Its Symbiotic Fungal Community To Improve Local Adaptation of the Host.

The genetic basis of plant local adaptation has been extensively studied, yet the interplay between local adaptation, plant genetic divergence, and the microbial community remains unclear. Our study used the restriction-site associated DNA sequencing (RAD-seq) approach to explore genetic divergence in Broussonetia papyrifera and used internal transcribed spacers (ITS) to characterize fungal community. RAD-seq results show that B. papyrifera individuals could be divided into three genotypes; this genotyping result was consistent with the classification of climate type at the sample site. Most of the 101 highly differentiated genes were related to stress resistance and the microbiome. Moreover, ß-diversity results indicated that genetic divergence had a significant effect on fungal community across all compartments (P < 0.01). At genus and operational taxonomic unit (OTU) level, Mortierella, Hannaella oryzae, OTU81578 (Mortierella), and OTU1665209 (H. oryzae) were found to be the major OTUs that contribute to differences in fungal community. The properties of cooccurrence networks vary greatly among three genotypes. The results of redundancy analysis (RDA) indicated that B. papyrifera-associated fungal community was significantly related to its local adaptability. Our findings suggest that genetic divergence of B. papyrifera is closely related to local adaptation, with significant effects on the associated fungal community, which in turn would enhance host local adaptability. This improves present understanding about the coevolution of microbial communities and the host plant.IMPORTANCE The coevolution of plants with the associated fungal community and its effect on plant adaptability are not clear, especially for native trees. This study focuses on the genetic basis of local adaptation in plants and the effect of genetic divergence of Broussonetia papyrifera on the associated fungal community. We identified genes related to the microbiome that are important for local adaptation of the host. Our results show that genetic divergence in B. papyrifera significantly affects the fungal community, which has a close connection with local adaptation. This helps us to understand the relationship between local adaptation, genetic divergence, and associated fungal communities. This study highlights the effect of plant genetic divergence on associated fungal community for native trees and establishes a close connection between this effect and local adaptability in the host. In addition, these observations lay a foundation for the research of coevolution of plants and their symbiotic microbiome through genome-wide association study (GWAS).

Atomically Dispersed Pt on Screw-like Pd/Au Core-shell Nanowires for Enhanced Electrocatalysis.

Engineering noble metal nanostructures at the atomic level can significantly optimize their electrocatalytic performance and remarkably reduce their usage. We report the synthesis of atomically dispersed Pt on screw-like Pd/Au nanowires by using ultrafine Pd nanowires as seeds. Au can selectively grow on the surface of Pd nanowires by an island growth pattern to fabricate surface defect sites to load atomically dispersed Pt, which can be confirmed by X-ray absorption fine structure measurements and aberration corrected HRTEM images. The nanowires with 2.74 at % Pt exhibit superior HER properties in acidic solution with an overpotential of 20.6 mV at 10 mA cm-2 and enhanced alkaline ORR performance with a mass activity over 15 times greater than the commercial platinum/carbon (Pt/C) catalysts.

The effect of plant compartments on the Broussonetia papyrifera-associated fungal and bacterial communities.

Plants associate with numerous microbes, but little is known about how microbiome components, especially fungi, adapt to specific plant compartments. The adaptability of microbial function to the plant compartment is also not clear especially for woody species. Here, we characterized the bacterial and fungal communities in root endosphere, stems, and rhizospheres of 33 Broussonetia papyrifera seedlings, based on amplification of 16S and ITS rRNA. Results showed that the α-diversity indexes of the bacterial community were significantly different in different plant compartments and they significantly increased from stem to root endosphere to the rhizosphere, whereas those of the fungal community were similar (p > 0.05). However, the result of constrained PCoA (CPCoA) and analysis of similarity (ANOSIM) showed that both bacterial and fungal compositions were significantly affected by plant compartments (p < 0.01). In detail, the operational taxonomic units (OTUs) distribution of the bacterial community was significantly different, but 249 of 252 fungal OTUs were shared in different plant compartments. Both the bacterial and fungal compositions were significantly influenced by plant compartments, based on the result on phyla, core OTUs, and indicator OTUs level. Further, 40 of 42 enriched KEGG pathways involving the bacteria also differed significantly among plant compartments (p < 0.01). This study provides an understanding of the influence of plant compartments on the microbiome and confirms that the disperse limitation of fungal OTUs across different plant compartments is smaller. This study sheds light on how the microbial community adapts to and thrives in different plant compartments.

A model-based analysis identifies differences in phenotypic resistance between in vitro and in vivo: implications for translational medicine within tuberculosis.

Proper characterization of drug effects on Mycobacterium tuberculosis relies on the characterization of phenotypically resistant bacteria to correctly establish exposure-response relationships. The aim of this work was to evaluate the potential difference in phenotypic resistance in in vitro compared to murine in vivo models using CFU data alone or CFU together with most probable number (MPN) data following resuscitation with culture supernatant. Predictions of in vitro and in vivo phenotypic resistance i.e. persisters, using the Multistate Tuberculosis Pharmacometric (MTP) model framework was evaluated based on bacterial cultures grown with and without drug exposure using CFU alone or CFU plus MPN data. Phenotypic resistance and total bacterial number in in vitro natural growth observations, i.e. without drug, was well predicted by the MTP model using only CFU data. Capturing the murine in vivo total bacterial number and persisters during natural growth did however require re-estimation of model parameter using both the CFU and MPN observations implying that the ratio of persisters to total bacterial burden is different in vitro compared to murine in vivo. The evaluation of the in vitro rifampicin drug effect revealed that higher resolution in the persister drug effect was seen using CFU and MPN compared to CFU alone although drug effects on the other bacterial populations were well predicted using only CFU data. The ratio of persistent bacteria to total bacteria was predicted to be different between in vitro and murine in vivo. This difference could have implications for subsequent translational efforts in tuberculosis drug development.

Thermal Emitting Strategy to Synthesize Atomically Dispersed Pt Metal Sites from Bulk Pt Metal.

Developing a facile route to access active and well-defined single atom sites catalysts has been a major area of focus for single atoms catalysts (SACs). Herein, we demonstrate a simple approach to generate atomically dispersed platinum via a thermal emitting method using bulk Pt metal as a precursor, significantly simplifying synthesis routes and minimizing synthesis costs. The ammonia produced by pyrolysis of Dicyandiamide can coordinate with platinum atoms by strong coordination effect. Then, the volatile Pt(NH3) x can be anchored onto the surface of defective graphene. The as-prepared Pt SAs/DG exhibits high activity for the electrochemical hydrogen evolution reaction and selective oxidation of various organosilanes. This viable thermal emitting strategy can also be applied to other single metal atoms, for example, gold and palladium. Our findings provide an enabling and versatile platform for facile accessing SACs toward many industrial important reactions.

Azidothymidine Produces Synergistic Activity in Combination with Colistin against Antibiotic-Resistant Enterobacteriaceae.

Bacterial infections remain a leading killer worldwide, which is worsened by the continuous emergence of antibiotic resistance. In particular, antibiotic-resistant Enterobacteriaceae are prevalent and extremely difficult to treat. Repurposing existing drugs and improving the therapeutic potential of existing antibiotics represent an attractive novel strategy. Azidothymidine (AZT) is an antiretroviral drug which is used in combination with other antivirals to prevent and to treat HIV/AIDS. AZT is also active against Gram-negative bacteria but has not been developed for that purpose. Here, we investigated the in vitro and in vivo efficacy of AZT in combination with colistin against antibiotic-resistant Enterobacteriaceae, including strains producing extended-spectrum beta-lactamases (ESBLs) or New Delhi metallo-beta-lactamase 1 (NDM) or carrying mobilized colistin resistance (mcr-1). The MIC was determined using the broth microdilution method. The combined effect of AZT and colistin was examined using the checkerboard method and time-kill analysis. A murine peritoneal infection model was used to test the therapeutic effect of the combination of AZT and colistin. The fractional inhibitory concentration index from the checkerboard assay demonstrated that AZT synergized with colistin against 61% and 87% of ESBL-producing Escherichia coli and Klebsiella pneumoniae strains, respectively, 100% of NDM-1-producing strains, and 92% of mcr-1-producing E. coli strains. Time-kill analysis demonstrated significant synergistic activities when AZT was combined with colistin. In a murine peritoneal infection model, AZT in combination with colistin showed augmented activities of both drugs in the treatment of NDM-1 K. pneumoniae and mcr-1 E. coli infections. The AZT and colistin combination possesses a potential to be used coherently to treat antibiotic-resistant Enterobacteriaceae infections.

Bedaquiline kills persistent Mycobacterium tuberculosis with no disease relapse: an in vivo model of a potential cure.

OBJECTIVES: Non-replicating persistent Mycobacterium tuberculosis is difficult to kill since the organisms become undetectable using our conventional diagnostic methods and tolerant to anti-TB drugs. Resuscitation-promoting factors (RPFs) have been used to 'wake up' non-replicating persisters, making them easy to detect. Bedaquiline is a novel bactericidal and sterilizing anti-TB drug with the potential to eradicate RPF-dependent persistent M. tuberculosis. We present the first head-to-head comparison between the standard anti-TB regimen and a bedaquiline-modified regimen in eradicating RPF-dependent persistent M. tuberculosis, using the well-defined Cornell Model. METHODS: M. tuberculosis-infected mice were treated for 14 weeks with either the standard regimen (rifampicin, isoniazid, pyrazinamide and ethambutol) or the same regimen where ethambutol was replaced by bedaquiline. The efficacy of both drug regimens was measured by cfu count elimination and eradication of persistent bacteria, which was evaluated using culture filtrate (CF) containing RPFs. At the end of treatment, the remaining cfu count-negative mice were administered hydrocortisone for 8 weeks. The induced disease relapse rates were determined by the percentage of mice that became positive for M. tuberculosis in the lung, spleen or both. RESULTS: The bedaquiline-containing regimen achieved total organ cfu count clearance at 8 weeks after treatment initiation, faster than the standard regimen (14 weeks). Importantly, the bedaquiline-containing regimen removed CF-dependent persistent bacilli at 8 weeks, leading to no disease relapse. CONCLUSIONS: A bedaquiline regimen eradicated persistent TB infections and completely prevented disease relapse in mice. These findings offer the potential for a faster cure for TB, with reduced relapse rate.

Calibration of position and orientation for point light source synchronously with single image in photometric stereo.

In this paper, a calibration method for non-isotropic point light source is developed, which is capable of calibrating position and orientation of the point light source with a single image synchronously. Based on the bidirectional reflectance distribution function (BRDF), the relationship between the shape of observed surface and the recorded grayscale image is firstly investigated in a more accurate way. Based on this model, a cost function is proposed to evaluate the estimation error, and a new cumulative, error-free iteration method is designed to recursively estimate the point light source parameters. The average simulation rebuilding root mean square error (RMSE) is below 0.9. The experiments are performed by calibrating a point light source in a photometric stereo measurement system, and the corresponding RMSE is below 1.2 in the unit of grayscale. Further analysis shows one image is enough to achieve the precision calibration using our proposed method.

The effect of environment on the microbiome associated with the roots of a native woody plant under different climate types in China.

Few studies have investigated the effect of environment on the root-associated microbiome, especially for woody plants in their native environment. The roots and rhizosphere soils of a native woody species (Broussonetia papyrifera) sampled across four different climate types in China were used to elucidate the influence of environment on the root-associated microbiome. Our results showed that the B. papyrifera root-associated microbiome contained abundant Proteobacteria and Basidiomycota, especially Pseudomonas and Rhizobium. The root-associated microbiomes were found to be significantly different under different climate types except for the bacterial community in the rhizosphere, and the proportion of bacterial operational taxonomic units (OTUs) shared among different climate types was lower than that of fungi. More than 50% of the total variance between microbiomes could be explained by 15 environmental factors, six of which, especially soil concentration phosphate and nitrate, had a significant effect. This study provided a comprehensive understanding of the root-associated microbiome of B. papyrifera and further confirmed the effect of environment on the root-associated microbiome of B. papyrifera under different climate types, with some exceptions in the rhizobacterial community and fungal OTUs. Our findings advanced knowledge of the effect of environment through an exploration of environmental factors and found that the nitrogen and phosphorus content represented the key factors.

Moxifloxacin Replacement in Contemporary Tuberculosis Drug Regimens Is Ineffective against Persistent Mycobacterium tuberculosis in the Cornell Mouse Model.

Tuberculosis (TB), which is caused by Mycobacterium tuberculosis, remains a leading killer worldwide, and disease control is hampered by the ineffective control of persistent infections. Substitution of moxifloxacin for isoniazid or ethambutol in standard anti-TB regimens reduces the treatment duration and relapse rates in animal studies, and 4-month regimens were not noninferior in clinical trials. Resuscitation-promoting factor (RPF)-dependent bacilli have recently been implicated in M. tuberculosis persistence. We aimed to investigate the therapeutic effects of the substitution of moxifloxacin for a drug used in the standard drug regimen in eradicating CFU count-positive and RPF-dependent persistent M. tuberculosis using the Cornell murine model. M. tuberculosis-infected mice were treated with regimens in which either isoniazid or ethambutol was replaced by moxifloxacin in the standard regimen. The efficacy of the regimens for bacterial CFU count elimination and removal of persistent tubercle bacilli, evaluated using culture filtrate (CF) derived from M. tuberculosis strain H37Rv, was compared to that of the standard regimen. We also measured disease relapse rates. The regimen in which moxifloxacin replaced isoniazid achieved total organ CFU count clearance at 11 weeks posttreatment, which was faster than that by the standard regimen (14 weeks), and showed a 34% lower relapse rate. The regimen in which moxifloxacin replaced ethambutol was similar to standard regimens in these regards. Importantly, neither the regimen in which moxifloxacin replaced isoniazid or ethambutol nor the standard regimen could remove CF-dependent persistent bacilli. The finding of CF-dependent persistent M. tuberculosis in TB treatment requires confirmation in human studies and has implications for future drug design, testing, and clinical applications.

Optimal doses of rifampicin in the standard drug regimen to shorten tuberculosis treatment duration and reduce relapse by eradicating persistent bacteria.

Objectives: Although high-dose rifampicin holds promise for improving tuberculosis disease control by eradication of persistent bacteria, the optimal dose of rifampicin that kills persistent bacteria and shortens the treatment duration is unknown. Methods: The Cornell mouse model was used to test the efficacy of rifampicin at elevated doses combined with isoniazid and pyrazinamide to kill actively growing and persistent bacilli and to measure relapse rate. Persistent bacteria were evaluated using Mycobacterium tuberculosis culture supernatant containing resuscitation-promoting factors. Pharmacokinetic parameters and dose-dependent activity for cultivable and persistent bacilli were determined. Results: Increasing doses of rifampicin in combination with isoniazid and pyrazinamide resulted in dose-dependent faster bacterial clearance. Evaluated both on solid media and in culture filtrate containing resuscitation-promoting factors, a regimen containing a standard dose of rifampicin at 10 mg/kg over 14 weeks failed to achieve organ sterility. In contrast, higher doses of rifampicin achieved organ sterility in a much shorter time of 8-11 weeks. Disease relapse, which occurred in 86% of mice treated with the standard regimen for 14 weeks, was completely prevented by rifampicin doses of ≥ 30 mg/kg. Conclusions: In the treatment of murine tuberculosis, a rifampicin dose of 30 mg/kg was sufficient to eradicate persistent M. tuberculosis, allowing shorter treatment duration without disease relapse.