Experimental warming accelerates positive soil priming in a temperate grassland ecosystem

Unravelling biosphere feedback mechanisms is crucial for predicting the impacts of global warming. Soil priming, an effect of fresh plant-derived carbon (C) on native soil organic carbon (SOC) decomposition, is a key feedback mechanism that could release large amounts of soil C into the atmosphere. However, the impacts of climate warming on soil priming remain elusive. Here, we show that experimental warming accelerates soil priming by 12.7% in a temperate grassland. Warming alters bacterial communities, with 38% of unique active phylotypes detected under warming. The functional genes essential for soil C decomposition are also stimulated, which could be linked to priming effects. We incorporate lab-derived information into an ecosystem model showing that model parameter uncertainty can be reduced by 32-37%. Model simulations from 2010 to 2016 indicate an increase in soil C decomposition under warming, with a 9.1% rise in priming-induced CO2 emissions. If our findings can be generalized to other ecosystems over an extended period of time, soil priming could play an important role in terrestrial C cycle feedbacks and climate change.

Ammonia-oxidizing bacteria and archaea exhibit differential nitrogen source preferences

Ammonia-oxidizing microorganisms (AOM) contribute to one of the largest nitrogen fluxes in the global nitrogen budget. Four distinct lineages of AOM: ammonia-oxidizing archaea (AOA), beta- and gamma-proteobacterial ammonia-oxidizing bacteria (β-AOB and γ-AOB) and complete ammonia oxidizers (comammox), are thought to compete for ammonia as their primary nitrogen substrate. In addition, many AOM species can utilize urea as an alternative energy and nitrogen source through hydrolysis to ammonia. How the coordination of ammonia and urea metabolism in AOM influences their ecology remains poorly understood. Here we use stable isotope tracing, kinetics and transcriptomics experiments to show that representatives of the AOM lineages employ distinct regulatory strategies for ammonia or urea utilization, thereby minimizing direct substrate competition. The tested AOA and comammox species preferentially used ammonia over urea, while β-AOB favoured urea utilization, repressed ammonia transport in the presence of urea and showed higher affinity for urea than for ammonia. Characterized γ-AOB co-utilized both substrates. These results reveal contrasting niche adaptation and coexistence patterns among the major AOM lineages.

Polyethylene Degradation by a Rhodococcous Strain Isolated from Naturally Weathered Plastic Waste Enrichment

Polyethylene (PE) is the most widely produced synthetic polymer and the most abundant plastic waste worldwide due to its recalcitrance to biodegradation and low recycle rate. Microbial degradation of PE has been reported, but the underlying mechanisms are poorly understood. Here, we isolated a Rhodococcus strain A34 from 609 day enriched cultures derived from naturally weathered plastic waste and identified the potential key PE degradation enzymes. After 30 days incubation with A34, 1% weight loss was achieved. Decreased PE molecular weight, appearance of C-O and C═O on PE, palmitic acid in the culture supernatant, and pits on the PE surface were observed. Proteomics analysis identified multiple key PE oxidation and depolymerization enzymes including one multicopper oxidase, one lipase, six esterase, and a few lipid transporters. Network analysis of proteomics data demonstrated the close relationships between PE degradation and metabolisms of phenylacetate, amino acids, secondary metabolites, and tricarboxylic acid cycles. The metabolic roadmap generated here provides critical insights for optimization of plastic degradation condition and assembly of artificial microbial communities for efficient plastic degradation.

[Detection rate and clinical characteristics of vulvar squamous intraepithelial lesion]

Objective: To explore the detection rate, clinical characteristics of vulvar squamous intraepithelial lesion (SIL). Methods: Women diagnosed with vulvar high-grade squamous intraepithelial lesions (HSIL) through colposcopy-guided biopsy from January 1, 2018 to August 31, 2022 in Obstetrics and Gynecology Hospital of Fudan University were included in a 1∶1 ratio with patients diagnosed with vulvar low-grade squamous intraepithelial lesions (LSIL) during the same period. Clinical characteristics including human papillomavirus (HPV) infection rate, genotype, cytology result, colposcopy impression, and lesion location were retrospectively analyzed. Results: (1) The proportion of vulvar SIL detected by colposcopy-guided biopsy increased annually from 2018 to 2022, with rates of 1.64% (740/45 057), 2.34% (1 110/47 402), 2.68% (1 108/41 335), 3.26% (1 536/47 078), 3.31% (667/20 155), with an average rate of 2.57% (5 161/201 027). (2) A total of 1 096 cases of vulvar HSIL and 1 096 cases of vulvar LSIL were included. The overall infection rate of HPV was 92.7% (1 993/2 150), with higher infection rate in vulvar HSIL patients than that in vulvar LSIL patients [96.0% (1 012/1 054) vs 89.5% (981/1 096); χ2=33.62, P<0.001]. Among vulvar HSIL patients, the common HPV genotype from high to low were HPV 16 (66.7%), HPV 52 (14.3%), and HPV 58 (10.0%). For vulvar LSIL patients, the most common HPV genotype were respectively HPV 16 (24.9%), HPV 6 (20.1%) and HPV 52 (17.1%). The overall sensitivity rate of cytology was 53.6%, with no significance difference between vulvar LSIL and HSIL groups (54.3% vs 52.9%; χ2=0.40, P=0.526). The accuracy of colposcopy impression for vulvar HSIL was lower than that for vulvar LSIL [40.2% (163/405) vs 81.7% (380/465); χ2=158.72, P<0.001]. About 57.3% (1 257/2 192) of the patients had concomitant cervical and vaginal lesions, with a higher rate in vulvar HSIL group than that in vulvar LSIL group [62.6% (686/1 096) vs 52.1% (571/1 096); χ2=24.67, P<0.001]. Unifocal lesion was the main type, with no significance difference between vulvar LSIL and HSIL groups [81.4% (381/468) vs 82.5% (386/468); χ2=0.18, P=0.671]. The most common lesion locations were the posterior commissure, followed by labia minora, vaginal vestibule, labia majora, perianal and clitoris. Conclusions: The detection rate of vulvar SIL under colposcopy is about 3%, and the infection rate of HPV is 92.7%. Vulvar SIL, especially vulvar HSIL, is likely to cause concomitant cervical and vaginal lesions. The accuracy of colposcopy in diagnosing vulvar HSIL is low. Therefore a comprehensive and careful examination of the vulva is necessary and suspicious vulvar lesions should be undergone colposcopy-guided biopsy for diagnosis.

[Comparative study of next generation sequencing and immunohistochemistry on molecular classification of endometrial carcinoma]

Objective: To investigate the differences in molecular classification of endometrial carcinoma (EC) between various technical methods and to explore molecular classification schemes suitable for Chinese population. Methods: The study used a comprehensive scheme of next generation sequencing (NGS) and immunohistochemistry for molecular classification of 254 EC cases that were obtained at Department of Pathology, Obstetrics and Gynecology Hospital of Fudan University, Shanghai, China from April 2021 to March 2022. According to the recommended threshold of Sanger sequencing which was approximate-20% variant allele fraction (VAF), NGS data were extracted to simulate the results of Sanger sequencing. Results: The 254 EC patients had a mean age of 51 years (range, 24 to 89 years). Combination of POLE (9-14 exons), TP53 total exons and microsatellite instability (MSI) detection was a better single scheme than NGS alone, while combination of MSI fragment analysis and conventional immunohistochemistry was the best solution and seemed best aligned with TCGA data and recent studies. POLE ultramuted type, mismatch repair defect type, TP53 mutant type and non-specific molecular characteristic type accounted for 11.4% (29/254), 31.5% (80/254), 22.4% (57/254) and 34.6% (88/254) of the cases, respectively. If Sanger sequencing was adopted for POLE and TP53 detection, the frequencies of these EC types were 9.1% (23/254), 31.5% (80/254), 12.9% (33/254) and 46.6% (118/254), respectively, with greatly increasing non-specific molecular characteristics cases. If POLE was detected by Sanger sequencing and others by immunohistochemistry, they were 9.1% (23/254), 42.2% (92/218), 13.8% (35/254) and 40.9% (105/254), respectively, with increasing the false positive rates of the mismatch repair defect group. Conclusions: Small and medium-sized NGS panels with MSI detection is a better solution than NGS alone. Sanger sequencing is currently available for POLE mutation detection, which is not sensitive enough for TP53 mutation detection, and seems equivalent to the efficiency of TP53 by immunohistochemistry. Further optimization of small and medium-sized NGS panels covering MSI detection and POLE and TP53 full exons may be the best choice for the future to meet national conditions.

Functional and structural diversification of incomplete phosphotransferase system in cellulose-degrading clostridia

Carbohydrate utilization is critical to microbial survival. The phosphotransferase system (PTS) is a well-documented microbial system with a prominent role in carbohydrate metabolism, which can transport carbohydrates through forming a phosphorylation cascade and regulate metabolism by protein phosphorylation or interactions in model strains. However, those PTS-mediated regulated mechanisms have been underexplored in non-model prokaryotes. Here, we performed massive genome mining for PTS components in nearly 15,000 prokaryotic genomes from 4,293 species and revealed a high prevalence of incomplete PTSs in prokaryotes with no association to microbial phylogeny. Among these incomplete PTS carriers, a group of lignocellulose degrading clostridia was identified to have lost PTS sugar transporters and carry a substitution of the conserved histidine residue in the core PTS component, HPr (histidine-phosphorylatable phosphocarrier). Ruminiclostridium cellulolyticum was then selected as a representative to interrogate the function of incomplete PTS components in carbohydrate metabolism. Inactivation of the HPr homolog reduced rather than increased carbohydrate utilization as previously indicated. In addition to regulating distinct transcriptional profiles, PTS associated CcpA (Catabolite Control Protein A) homologs diverged from previously described CcpA with varied metabolic relevance and distinct DNA binding motifs. Furthermore, the DNA binding of CcpA homologs is independent of HPr homolog, which is determined by structural changes at the interface of CcpA homologs, rather than in HPr homolog. These data concordantly support functional and structural diversification of PTS components in metabolic regulation and bring novel understanding of regulatory mechanisms of incomplete PTSs in cellulose-degrading clostridia.

[Efficacy of Hintermann calcaneal lengthening osteotomy for flexible flatfoot]

Objective: To investigate the clinical efficacy of Hintermann osteotomy (H-LCL) for flexible flatfoot. Methods: A follow-up study. Clinical data of 30 patients with flexible flatfoot treated with H-LCL operation from January 2020 to December 2021 in Sports Medical Center of the First Affiliated Hospital of Army Medical University were retrospectively analyzed. There were 8 males and 22 females, with a mean age of (39.0±15.2) years. The mean time from symptom onset to the diagnosis［M（Q₁，Q₃）］was 24.0 (5.5, 102.0) months. The functional and imaging scores of the patients before and after the last follow-up were compared to evaluate the clinical efficacy of the operation. The functional scores included American Orthopedic Foot and Ankle Society (AOFAS) score, visual analogue scale (VAS) of pain, pain interference (PI) and physical function (PF) index in Patient-Reported Outcomes Measurement Information System (PROMIS). And the imaging scores included Meary's angle, calcaneal pitch angle, calcaneal valgus angle and talonavicular coverage angle. Results: The mean operation time was (82.3±24.4) min, and the follow-up periods was (17.9±6.9) months. At the last follow-up, VAS of pain [M(Q₁, Q₃)] decreased from 5 (4, 6) to 2 (1, 2); PI decreased from 59.8±5.0 to 44.6±5.7; AOFAS increased from 65.2±10.0 to 85.8±3.3; PF increased from 50 (48.5,51.0) to 58.5 (54.0, 66.0); Meary's angle (antero-posterior image) decreased from 15.7° (10.1°, 29.2°) to 3.9° (2.6°, 5.3°); Meary's angle (lateral image) decreased from 13.5°±6.8° to 4.4°±2.6°; calcaneal pitch angle increased from 14.0°±3.3° to 18.6°±4.2°; calcaneal valgus angle decreased from 12.6°±7.3° to 4.3°±2.5°; and talonavicular coverage angle decreased from 20.9°±10.7° to 7.7°±5.2°. The up-mentioned parameters were all improved statistically significant at the last follow-up when compared with those before the operation (all P<0.05). Conclusion: H-LCL brings a significant improvement of clinical outcome scores and good radiological correction of flatfoot deformities in correcting flexible flatfoot, it conforms to the anatomical characteristics of the subtalar joint.

Target integration of an exogenous β-glucosidase enhances cellulose degradation and ethanol production in Clostridium cellulolyticum

The bacteria Clostridium cellulolyticum is a promising candidate for consolidated bioprocessing (CBP). However, genetic engineering is necessary to improve this organism's cellulose degradation and bioconversion efficiencies to meet standard industrial requirements. In this study, CRISPR-Cas9n was used to integrate an efficient β-glucosidase into the genome of C. cellulolyticum, disrupting lactate dehydrogenase (ldh) expression and reducing lactate production. The engineered strain showed a 7.4-fold increase in β-glucosidase activity, a 70% decrease in ldh expression, a 12% increase in cellulose degradation, and a 32% increase in ethanol production compared to wild type. Additionally, ldh was identified as a potential site for heterologous expression. These results demonstrate that simultaneous β-glucosidase integration and lactate dehydrogenase disruption is an effective strategy for increasing cellulose to ethanol bioconversion rates in C. cellulolyticum.

Niche Modification by Sulfate-Reducing Bacteria Drives Microbial Community Assembly in Anoxic Marine Sediments

Sulfate-reducing bacteria (SRB) are essential functional microbial taxa for degrading organic matter (OM) in anoxic marine environments. However, there are little experimental data regarding how SRB regulates microbial communities. Here, we applied a top-down microbial community management approach by inhibiting SRB to elucidate their contributions to the microbial community during OM degradation. Based on the highly replicated microcosms (n = 20) of five different incubation stages, we found that many microbial community properties were influenced after inhibiting SRB, including the composition, structure, network, and community assembly processes. We also found a strong coexistence pattern between SRB and other abundant phylogenetic lineages via positive frequency-dependent selection. The relative abundances of the families Synergistaceae, Peptostreptococcaceae, Dethiosulfatibacteraceae, Prolixibacteraceae, Marinilabiliaceae, and Marinifilaceae were simultaneously suppressed after inhibiting SRB during OM degradation. A close association between SRB and the order Marinilabiliales among coexisting taxa was most prominent. They contributed to preserved modules during network successions, were keystone nodes mediating the networked community, and contributed to homogeneous ecological selection. The molybdate tolerance test of the isolated strains of Marinilabiliales showed that inhibited SRB (not the inhibitor of SRB itself) triggered a decrease in the relative abundance of Marinilabiliales. We also found that inhibiting SRB resulted in reduced pH, which is unsuitable for the growth of most Marinilabiliales strains, while the addition of pH buffer (HEPES) in SRB-inhibited treatment microcosms restored the pH and the relative abundances of these bacteria. These data supported that SRB could modify niches to affect species coexistence. IMPORTANCE Our model offers insight into the ecological properties of SRB and identifies a previously undocumented dimension of OM degradation. This targeted inhibition approach could provide a novel framework for illustrating how functional microbial taxa associate the composition and structure of the microbial community, molecular ecological network, and community assembly processes. These findings emphasize the importance of SRB during OM degradation. Our results proved the feasibility of the proposed study framework, inhibiting functional taxa at the community level, for illustrating when and to what extent functional taxa can contribute to ecosystem services.

[Genetic variations in four geographical isolates of Gohieria fusca based on cytochrome b and internal transcribed spacer genes]

OBJECTIVE

To investigate the genetic diversity and genetic differentiation of different geographical isolates of Gohieria fusca.

METHODS

G. fusca isolates were sampled from Wuhu (WH), Bengbu (BB) and Bozhou cities (BZ) of Anhui Province and Jiaxing City of Zhejiang Province (JX). Mitochondrial cytochrome b (Cytb) and ribosomal internal transcribed spacer (ITS) genes were amplified in WH, BB, BZ and JX isolates of G. fusca using PCR assay. The gene sequences were edited and aligned using the software Chromas 2 and DNASTAR 1.00, and the haplotype, haplotype diversity (Hd) and nucleotide polymorphism (Pi) of each isolate were calculated using the software DnaSP 5.10.00. The genetic differentiation among isolates (F_st) and gene flow value (N_m) were estimated using the software MEGA 10.2, and a phylogenetic tree was built. Tests of neutrality and analysis of molecular variance (AMOVA) were performed using the software Arlequin 3.1 and a haplotype network was built based on the Median-Joining network using the software Network 10.2.

RESULTS

PCR assay showed that the sizes of the Cytb and ITS genes were 372 bp and 1 301 to 1 320 bp, respectively. All four isolates of G. fusca presented high genetic diversity based on mitochondrial Cytb and ITS genes (Hd = 0.804, Pi = 0.006 91). AMOVA showed genetic differentiation among geographical isolates of G. fusca (F_st = 0.202 40, P < 0.05), and the genetic variation was mainly caused by intra-population variations (79.76%). Gene flow analysis showed a high level of gene flow among G. fusca isolates (N_m > 1). Tests of neutrality based on Cytb gene measured a Tajima's D value of -1.796 31 (P < 0.05) and a Fu's FS value of -3.293 98 (P < 0.05) in WH isolate of G. fusca, indicating population expansion in WH isolate of G. fusca. Haplotype network analysis and phylogenetic analysis revealed no remarkable geographical distribution pattern among different geographical isolates of G. fusca. All four isolates of G. fusca presented high genetic diversity (Hd = 0.985, Pi = 0.011 97). AMOVA showed moderate level of genetic differentiation between four isolates (F_st = 0.104 62, P < 0.05). The tests of neutrality based on ITS genes measured a Tajima's D value of -6.088 20 and a Fu's FS value of -1.935 99 (both P > 0.05) in the whole isolate of G. fusca, indicating no obviously population expansion.

CONCLUSIONS

The four geographical isolates of G. fusca have high genetic diversity and remarkable genetic differentiation. Since a high level of gene flow is detected among different geographical isolates of G. fusca, no obvious geographical distribution pattern of G. fusca is found.

[Low-dose helical CT projection data restoration using noise estimation]

OBJECTIVE

To build a helical CT projection data restoration model at random low-dose levels.

METHODS

We used a noise estimation module to achieve noise estimation and obtained a low-dose projection noise variance map, which was used to guide projection data recovery by the projection data restoration module. A filtering back-projection algorithm (FBP) was finally used to reconstruct the images. The 3D wavelet group residual dense network (3DWGRDN) was adopted to build the network architecture of the noise estimation and projection data restoration module using asymmetric loss and total variational regularization. For validation of the model, 1/10 and 1/15 of normal dose helical CT images were restored using the proposed model and 3 other restoration models (IRLNet, REDCNN and MWResNet), and the results were visually and quantitatively compared.

RESULTS

Quantitative comparisons of the restored images showed that the proposed helical CT projection data restoration model increased the structural similarity index by 5.79% to 17.46% compared with the other restoration algorithms (P < 0.05). The image quality scores of the proposed method rated by clinical radiologists ranged from 7.19% to 17.38%, significantly higher than the other restoration algorithms (P < 0.05).

CONCLUSION

The proposed method can effectively suppress noises and reduce artifacts in the projection data at different low-dose levels while preserving the integrity of the edges and fine details of the reconstructed CT images.

[An adaptive CT metal artifact reduction algorithm that combines projection interpolation and physical correction]

OBJECTIVE

To propose an adaptive weighted CT metal artifact reduce algorithm that combines projection interpolation and physical correction.

METHODS

A normalized metal projection interpolation algorithm was used to obtain the initial corrected projection data. A metal physical correction model was then introduced to obtain the physically corrected projection data. To verify the effectiveness of the method, we conducted experiments using simulation data and clinical data. For the simulation data, the quantitative indicators PSNR and SSIM were used for evaluation, while for the clinical data, the resultant images were evaluated by imaging experts to compare the artifact-reducing performance of different methods.

RESULTS

For the simulation data, the proposed method improved the PSNR value by at least 0.2 dB and resulted in the highest SSIM value among the methods for comparison. The experiment with the clinical data showed that the imaging experts gave the highest scores of 3.616±0.338 (in a 5-point scale) to the images processed using the proposed method, which had significant better artifact-reducing performance than the other methods (P < 0.001).

CONCLUSION

The metal artifact reduction algorithm proposed herein can effectively reduce metal artifacts while preserving the tissue structure information and reducing the generation of new artifacts.

Molecular basis for coordinating secondary metabolite production by bacterial and plant signaling molecules

The production of secondary metabolites is a major mechanism used by beneficial rhizobacteria to antagonize plant pathogens. These bacteria have evolved to coordinate the production of different secondary metabolites due to the heavy metabolic burden imposed by secondary metabolism. However, for most secondary metabolites produced by bacteria, it is not known how their biosynthesis is coordinated. Here, we showed that PhlH from the rhizobacterium Pseudomonas fluorescens is a TetR-family regulator coordinating the expression of enzymes related to the biosynthesis of several secondary metabolites, including 2,4-diacetylphloroglucinol (2,4-DAPG), mupirocin, and pyoverdine. We present structures of PhlH in both its apo form and 2,4-DAPG-bound form and elucidate its ligand-recognizing and allosteric switching mechanisms. Moreover, we found that dissociation of 2,4-DAPG from the ligand-binding domain of PhlH was sufficient to allosterically trigger a pendulum-like movement of the DNA-binding domains within the PhlH dimer, leading to a closed-to-open conformational transition. Finally, molecular dynamics simulations confirmed that two distinct conformational states were stabilized by specific hydrogen bonding interactions and that disruption of these hydrogen bonds had profound effects on the conformational transition. Our findings not only reveal a well-conserved route of allosteric signal transduction in TetR-family regulators but also provide novel mechanistic insights into bacterial metabolic coregulation.

In vivo Functional Characterization of Hydrophilic X2 Modules in the Cellulosomal Scaffolding Protein

As part of free cellulases or scaffolding proteins in cellulosomes, the hydrophilic non-catalytic X2 module is widely distributed in cellulolytic Clostridia or other Firmicutes bacteria. Previous biochemical studies suggest that X2 modules might increase the solubility and substrate binding affinity of X2-bearing proteins. However, their in vivo biological functions remain elusive. Here we employed CRISPR-Cas9 editing to genetically modify X2 modules by deleting the conserved motif (NGNT) from the CipC scaffoldin. Both single and double X2 mutants (X2-N: near the N terminus of CipC; X2-C: near the C terminus of CipC) presented similar stoichiometric compositions in isolated cellulosomes as the wildtype strain (WT). These X2 mutants had an elongated adaptation stage during growth on cellulose compared to cellobiose. Compared to WT, the double mutant ΔX2-NC reduced cellulose degradation by 15% and the amount of released soluble sugars by 63%. Since single X2 mutants did not present such obvious physiological changes as ΔX2-NC, there seems to be a functional redundancy between X2 modules in CipC. The in vivo adhesion assay revealed that ΔX2-NC decreased cell attachment to cellulose by 70% but a weaker effect was also overserved in single X2 mutants. These results highlight the in vivo biological role of X2 in increasing cellulose degradation efficiency by enhancing the binding affinity between cells and cellulose, which provides new perspectives for microbial engineering.

[Molecular characterization of Staphylococcus aureus ST6 and ST7 isolates from food-borne illness outbreaks]

Objective: To analyze the Staphylococcal enterotoxins, Staphylococcal enterotoxin genes, drug resistance and molecular typing of 41 Staphylococcus aureus isolates from 2 food-borne illness outbreaks on 21 August and 27 September 2020 in Guangzhou. Methods: A total of 41 Staphylococcus aureus isolates from 2 outbreaks were analyzed by multilocus sequence typing (MLST) and spa typing. The Staphylococcal enterotoxins typing and the Staphylococcal enterotoxin genes of the isolates were analyzed by ELISA and PCR, respectively. The antimicrobial susceptibility of the isolates was performed by disc diffusion. 21 Staphylococcus aureus isolates were characterized using whole genome sequencing (WGS). Based on the whole genome single nucleotide polymorphism (SNP), the phylogenetic tree was constructed by Snippy. Results: 41 Staphylococcus aureus isolates were divided into 2 types by MLST and spa typing: ST6-t701 and ST7-t091. 2 ST7-t091 isolates were identified as methicillin-resistant Staphylococcus aureus (MRSA). 25 ST7-t091 isolates and 14 ST6-t701 isolates were methicillin-sensitive Staphylococcus aureus (MSSA), and were resistant to 7 and 6 antibiotics, respectively. All isolates were positive for sea by PCR. WGS revealed all 21 isolates carried scn, sak, sea, hla, hld, hlgA, hlgB, hlgC, lukD virulence genes. The results showed the isolates contained an immune evasion cluster type D which located in bacteriophage ϕSa3. The SNP phylogenetic tree showed 2 MRSA ST7-t091 were constituted a separate clade from the 12 MSSA ST7-t091 isolates and 7 ST6-t701 isolates showed high similarity to each other. Conclusion: Base on the results of phylogenetic analysis, the 2 food-borne illness outbreaks occurred on 21 August and 27 September 2020 are caused by the combination of the MRSA ST7-t091 strain and the MSSA ST7-t091 strain, and the MSSA ST6-t701 strain, respectively. All isolates have high level of antibiotic resistance and carry high virulent genes.

[Identification of traditional Chinese drugs containing active ingredients for treating myocardial infarction and analysis of their therapeutic mechanisms by network pharmacology and molecular docking]

OBJECTIVE

To identify traditional Chinese drugs that contain active ingredients for treatment of myocardial infarction (MI) and explore their therapeutic mechanisms using network pharmacology and molecular docking technology.

METHODS

The TCMSP database was used for screening the traditional Chinese drugs containing active ingredients for treating MI, and the related targets of MI and the candidate drugs were obtained from Genecards, OMIM, PharmGkb and PharmMapper databases. The common target network of the drug targets and disease targets was established using Venny2.1.0 software. GO and KEGG signal pathway enrichment analysis of the common targets was performed, and the protein-protein interaction (PPI) network was constructed for the targets. The targets in the PPI network were analyzed to identify the key targets, for which GO and KEGG pathway enrichment analyses were performed. Molecular docking was performed for the candidate ingredients and the key targets, and a total score ≥6 was used as the criteria for screening the therapeutic ingredients and their docking binding with key targets was verified. A human umbilical vein endothelial cell (HUVEC) model of oxygen-glucose deprivation (OGD) was used to validate the candidate ingredients and the key therapeutic targets for MI by Western blotting.

RESULTS

Our analysis identified Salvia miltiorrhiza and Dalbergiae odoriferae as the candidate drugs rich in active ingredients for treatment of MI. These ingredients involved 16 key therapeutic targets for MI, which participated in such biological processes as inflammatory response, angiogenesis, energy metabolism and oxidative stress and the pathways including HIF-1, VEGF, and TNF pathways. Sclareol and PTGS2 in Salvia miltiorrhiza and formononetin and KDR in Dalbergiae odoriferae all had high docking total scores. Western blotting showed that at medium and high doses, sclareol significantly inhibited PTGS2 expression and formononetin promoted KDR expressions in the cell models in a dose-dependent manner (P < 0.05).

CONCLUSION

Both Salvia miltiorrhiza and Dalbergiae odoriferae have good therapeutic effects on MI. Sclareol in Salvia miltiorrhiza and formononetin in Dalbergiae odoriferae regulate the expressions of KDR and PTGS2, respectively, to modulate the inflammatory response, angiogenesis, oxidative stress and energy metabolism and thus produce myocardial protective effects.

Cas9 Nickase-Based Genome Editing in Clostridium cellulolyticum

Clostridium cellulolyticum is a model mesophilic, cellulolytic bacterium, with the potential to produce biofuels from lignocellulose. However, the natural cellulose utilization efficiency is quite low and, therefore, metabolically engineered strains with increased efficiency can decrease both the overall cost and time required for biofuel production. Traditional genetic tools are inefficient, expensive, and time-consuming, but recent developments in the use of CRISPR-Cas genetic editing systems have greatly expanded our ability to reprogram cells. Here we describe an established protocol enabling one-step versatile genome editing in C. cellulolyticum. It integrates Cas9 nickase (Cas9n) which introduces a single nick that triggers repair via homologous recombination (SNHR) to edit genomic loci with high efficiency and accuracy. This one-step editing is achieved by transforming an all-in-one vector to coexpress Cas9n and a single guide RNA (gRNA) and carries a user-defined homologous donor template to promote SNHR at a desired target site. Additionally, this system has high specificity and allows for various types of genomic editing, including markerless insertions, deletions, substitutions, and even multiplex editing.

Permafrost thaw with warming reduces microbial metabolic capacities in subsurface soils

Microorganisms are major constituents of the total biomass in permafrost regions, whose underlain soils are frozen for at least two consecutive years. To understand potential microbial responses to climate change, here we examined microbial community compositions and functional capacities across four soil depths in an Alaska tundra site. We showed that a 5-year warming treatment increased soil thaw depth by 25.7% (p = .011) within the deep organic layer (15-25 cm). Concurrently, warming reduced 37% of bacterial abundance and 64% of fungal abundances in the deep organic layer, while it did not affect microbial abundance in other soil layers (i.e., 0-5, 5-15, and 45-55 cm). Warming treatment altered fungal community composition and microbial functional structure (p < .050), but not bacterial community composition. Using a functional gene array, we found that the relative abundances of a variety of carbon (C)-decomposing, iron-reducing, and sulphate-reducing genes in the deep organic layer were decreased, which was not observed by the shotgun sequencing-based metagenomics analysis of those samples. To explain the reduced metabolic capacities, we found that warming treatment elicited higher deterministic environmental filtering, which could be linked to water-saturated time, soil moisture, and soil thaw duration. In contrast, plant factors showed little influence on microbial communities in subsurface soils below 15 cm, despite a 25.2% higher (p < .05) aboveground plant biomass by warming treatment. Collectively, we demonstrate that microbial metabolic capacities in subsurface soils are reduced, probably arising from enhanced thaw by warming.

Materials in advanced design of personal protective equipment: a review

The outbreak of the Covid-19 pandemic has aroused tremendous attention toward personal protective equipment (PPE) in both scientific research and industrial manufacture. Despite decades of development in PPE design and fabrication, there's still much room for further optimization, in terms, of both protection performance and wear comfort. Interdisciplinary efforts have been devoted to this research field in recent years. Significantly, the innovation of materials, which brings about improved performance and versatile new functions for PPEs, has been widely adopted in PPE design. In this minireview, recent progress in the development of novel materials and structural designs for PPE application are presented in detail with the introduction of various material-based strategies for different PPE types, as well as the examples, which apply auxiliary components into face masks to enrich the functionalities and improve the personal feelings in the pandemic period.

[Mid-and-long term follow-up of autogenous tibial periosteum-bone complex transplantation for treatment of cystic osteochondral lesion of talus]

Objective: To further clarify the mid-and-long term follow-up results of self-designed tibial periosteum-bone complex transplantation in the treatment of Hepple V osteochondral lesion of the talus(OLTs). Methods: The clinical data of 30 patients with Hepple V OLTs who received treatment in the Sports Medicine Center of the First Affiliated Hospital of Army Military Medical University from October 2011 to January 2019 were analyzed. There were 19 males and 11 females with a mean age of (40±11) years. Patients were treated with autogenous tibial periosteum-bone complex transplantation and were followed up for at least 2 years. The Foot and Ankle Outcome Score (FAOS), American Orthopedic Foot and Ankle Society (AOFAS) ankle-hindfoot score, the visual analog scale score (VAS) of pain, the simplified symptomatology evaluation (SSE) and imaging results before the operation and at the follow-up were recorded and compared. Results: The cohort were followed-up for a mean of 63.9 months (range 24-110 months). Twenty-nine (96.7%) patients were satisfied with the curative effect. The FAOS score was improved from 53.5±6.2 preoperatively to 88.4±6.6 at the final follow-up (P<0.001). The AOFAS ankle-hindfoot scale improved from 61.6±8.2 preoperatively to 90.8±6.8 at the last follow-up (P<0.001). The VAS score decreased from 4.3±0.2 preoperative to 0.7±0.7 at the last follow-up (P<0.001). The SSE score was poor in 14 cases (46.7%), average in 16 cases (53.3%) before the operation; and it was excellent in 23 cases (76.7%), good in 6 cases (20%), average in 1 case (3.3%) at the last follow-up. Imaging examination showed cystic change cure rate was 83.3%, cartilage defects were completely infilled with repair tissue, which didn't show any signs of degeneration. However, repair tissue showed varying degrees of heterogeneous signal compared to the normal articular cartilage. Conclusion: The autograft of tibial periosteum-bone complex transplantation is a safe and feasible method for the treatment of osteochondral lesion of the talus in Hepple V type, with good mid-and-long term clinical effect.

[Risk stratified management of cervical adenocarcinoma in situ based on cone margin state]

Objective: To investigate the hierarchical management scheme of cervical adenocarcinoma in situ (AIS) based on cervical conization margin state. Methods: All medical records of 249 patients diagnosed as AIS by loop electrosurgical excision procedure (LEEP) conization from Jan. 2010 to Dec. 2015 in Obstetrics and Gynecology Hospital of Fudan University were retrospectively reviewed, to explore the relationship between the status of the resection margin and the residual lesion after LEEP, and the multivariate logistic regression method was used to analyze the related factors that affect the residual lesion after LEEP in cervical AIS patients. Results: (1) The age of 249 cervical AIS patients was (40±8) years old (range: 23-71 years old). Of the 249 patients, 19 (7.6%, 19/249) had residual lesions; 69 cases were pathologically diagnosed as AIS after LEEP, and the residual lesion rate was 13.0% (9/69), which was significantly higher than that of AIS + high-grade squamous intraepithelial lesion [5.6% (10/180); χ²=3.968,P=0.046]; 33 cases were multifocal lesions, the residual rate of lesions was 21.2% (7/33), which was significantly higher than that of single focal lesions patients [5.6% (12/216); χ²=7.858, P=0.005]; 181 patients underwent endocervical curettage (ECC) before surgery, the residual rate of lesions in ECC-positive patients was 14.0% (14/100) , significantly higher than that of ECC-negative patients [4.9% (4/81); χ²=4.103, P=0.043]. (2) Among 249 cases of AIS patients, the positive rate of resection margins after LEEP was 35.3% (88/249); the residual rate of lesions in patients with positive resection margins (14.8%, 13/88) was significantly higher than those with negative margins [3.8%(6/156); χ²=9.355, P=0.002]. The age of patients underwent total hysterectomy after LEEP was (43±7) years old, which was significantly higher than that of patients who did not undergo total hysterectomy [(37±8) years old; t=6.518, P<0.01].Among the patients underwent total hysterectomy after LEEP, 3 cases (2.0%, 3/152) had fertility requirements, while 38 cases (39.2%, 38/97) did not underwent total hysterectomy, the difference between the two groups was statistically significant (χ²=59.579, P<0.01). Among the 152 patients who underwent total hysterectomy after LEEP, the residual rate of lesions was 11.8% (18/152); the residual rate of lesions in patients with positive resection margins was significantly higher than that of patients with negative resection margins [18.8% (12/64) vs 7.0% (6/86); χ²=4.861, P=0.028]. The median follow-up time of 97 patients who did not undergo total hysterectomy after LEEP was 32 months (range: 4-70 months). During the follow-up period, 3 cases of cervical AIS recurrence (3.1%, 3/97) and were followed by hysterectomy,no invasive adenocarcinoma were seen. (3) Multivariate logistic regression analysis showed that the positive resection margin (OR=4.098, 95%CI: 1.235-13.595, P=0.021), multifocal lesions (OR=5.464, 95%CI: 1.494-19.981, P=0.010) were independent risk factors that affected the residual lesions in patients with cervical AIS after LEEP. Conclusions: The cervical AIS patients after LEEP conization suggested be stratified by cone margin state as the first-line stratified index, age and fertility needs as the second-line stratified management index. The individualized management plan should be developed based on comprehensive assessment of high-risk factors of residual lesions.

Proteomic analysis reveals the mechanism of different environmental stress-induced tolerance of Pseudomonas aeruginosa to monochloramine disinfection

Although drinking water disinfection proved to be an effective strategy to eliminate many pathogens, bacteria can still show disinfection tolerance in drinking water distribution systems. To date, the molecular mechanisms on how environmental stress affects the tolerance of Pseudomonas aeruginosa to monochloramine are not well understood. Here, we investigated how three stress conditions, namely starvation, low temperature, and starvation combined with low temperature, affected the monochloramine tolerance of Pseudomonas aeruginosa, an opportunistic pathogen commonly found in drinking water distribution systems. All stress conditions significantly promoted monochloramine tolerance, among which starvation had the most drastic effects. Proteomic analyses suggested that the three conditions not only triggered a positive antioxidant defense against oxidative damages but also prepared the bacteria to employ a passive defense mechanism against disinfectants via dormancy. Moreover, the expression of antioxidant enzymes reached the maximum under the starvation condition and further low temperature treatment had little effect on bacterial response to oxidative stress. Instead, we found further treatment of the starved cells with low temperature decreased the osmotic stress response and the stringent response, which generally play pivotal roles in disinfection tolerance. Taken together, these findings shed light on how abiotic factors influence the bacterial disinfection tolerance and will aid design of efficient strategies to eliminate Pseudomonas aeruginosa from drinking water.

P–563 Assessing ovarian age: Could we use leukocyte telomere length as a surrogate marker of cumulus cells telomere content?

Study question

Is leukocyte telomere length (LTL) correlated with cumulus cells telomere length (CCTL) in an age-heterogeneous women population?

Summary answer

LTL showed a positive correlation with CCTL in the studied population. Hence, its potential value as indicator of ovarian age would deserve further evaluation.

What is known already

Progressive telomere shortening has been related to ovarian aging and genomic instability during early development. A positive correlation between short telomere length of the first polar body and aneuploidy rate has been reported. CCTL has shown to be a biomarker of oocyte and embryo quality, but its assessment is impractical. LTL has been proposed as a surrogate of TL of follicular cells, but telomere lengthening through folliculogenesis could be controlled by different mechanisms. Thus, we aimed to determine if LTL in an age-heterogeneous population is correlated with CCTL and therefore considered an accurate surrogate for telomere length in the ovary.

Study design, size, duration

In this prospective non-interventional cohort study, 35 egg donors and 17 women undergoing Preimplantation Genetic Testing for Aneuploidy (PGT-A) treatment were included during sixteen months. Following controlled ovarian stimulation determined by treating physicians, oocyte retrieval was performed 36 hours after final maturation induction. Cumulus cells (CC) for telomere length (TL) measurement were obtained after the pick-up and oocyte stripping. A blood sample was collected through peripheral venous access for LTL measurement.

Participants/materials, setting, methods

Genomic DNA of CC and leukocytes from the 52 subjects was isolated. Average delta cycle threshold (ΔCt) was determined using a SYBR green quantitative real-time PCR protocol for relative TL. For normalization of measurements, a Taqman assay for the multicopy gene Alu was performed. ΔCtL and ΔCtCC were compared by a paired t-test analysis and the fold change was calculated. Additionally, the association between them and patient age was analyzed by a Pearson correlation test.

Main results and the role of chance

Mean participant’s age was 29.94 ± 7.55 years and mean values for ΔCtL and ΔCtCC were 7.99 ± 0.53 and 7.46 ± 0.75, respectively. A positive significant correlation was found between age and ΔCt (ΔCtL: R2=0.71, p-value=5.18e–09; ΔCtCC: R2=0.47, p-value=0.00049). Since ΔCt values are inversely proportional to the amount of nucleic acids amplified and, therefore, to the telomere length, this correlation means that TL in both cell types decreases as women age. Additionally, ΔCtL was significantly higher than ΔCtCC (ΔCt fold change: 0.93, p-value=9e–07), meaning that CC showed significantly longer telomeres than leukocytes, thus supporting our previous published results in young egg donors. When analyzing the ΔCtL and ΔCtCC in these age-heterogeneous sample, a positive moderate and significant correlation was observed (R2=0.42, p-value=0.002). Thus, LTL could be suggested as a potential indicator of CCTL and therefore as a candidate for a biological marker of ovarian aging.

Limitations, reasons for caution

The sample size of this study was moderate and perhaps increasing the number of subjects might give additional strength to our findings. In addition, although relative telomere length allowed for adequate comparison between subjects, this method did not allow for absolute TL measurement.

Wider implications of the findings: While reproductive implications of LTL measurement need to be further studied, our results support the potential usefulness of LTL measurement as an indicator of CCTL and ovarian aging when analyzing an age-heterogeneous population. Further, our findings suggest that CC could possess different mechanisms to cope against telomere length shortening.

Trial registration number

Not applicable

Comparison of long non-coding RNAs in adipose and muscle tissues between seven indigenous Chinese and the Yorkshire pig breeds

lncRNAs play crucial roles in fat metabolism in animals. Previously, we have compared the mRNA transcriptome profiles between seven fat-type Chinese pig breeds and one lean-type Western breed (Yorkshire, YY). The associations between differentially expressed (DE) genes and phenotypical traits were investigated. In the present study, to further explore the underlying regulatory mechanisms, lncRNAs were sequenced and compared between YY and Chinese indigenous breeds. The results showed 9114 and 7538 DE lncRNAs between at least one Chinese breed and the YY breed in the adipose and muscle tissue respectively. KEGG enrichment analysis revealed that the target genes of these DE lncRNAs mainly influenced the glucolipid metabolism, which is an important process affecting meat quality. Correlation analyses between the DE lncRNA and DE mRNA genes related to meat quality and growth traits were performed. The results showed that LTCONS_00073280 was associated with intramuscular fat content. Four lncRNAs (LTCONS_00101781, LTCONS_00037879, LTCONS_00088260 and LTCONS-00128343) might mediate backfat thickness. Overall, this study provides candidate lncRNAs that potentially affect meat quality, which might be useful for molecular breeding of pig breeds in future.

[Early clinical efficacy analysis of personalized three-dimensional printing talus prosthesis in the treatment of collapse talus necrosis]

Object To examine the preliminary clinical efficacy of custom-made three-dimensional(3D) printed talus prosthesis in the treatment of collapse talus necrosis. Methods: The clinical data of 8 patients who received 3D printed custom-made talus prostheses replacement for severe collapsed necrosis of the talus at the Orthopaedic Sports Medical Center, the First Affiliated Hospital to Army Medical University were analyzed retrospectively.All patients were male,with an average age of 38.0 years (range:22 to 65 years).There were 5 cases of left talus collapse and 3 cases of right talus collapse,with the course of disease of 29.7 weeks (range:6 to 96 weeks).The CT data of contralateral healthy talus were used for mirror image design references for the prosthesis,and the electron-beam 3D printing technology was used to prepare the prosthesis.Titanium alloy (Ti6Al4V) was taken as the material for the preparation of the talus body prosthesis,and Co-Cr-Mo material was used as the material for the preparation of the tibialis talus lateral joint surface prosthesis,and the subtalar joint surface of the prosthesis was made from a microporous casting technique.The prosthesis was analyzed preoperatively by digital three-dimensional finite element analysis and solid comparison techniques to measure anatomic match of the prosthesis.A longitudinal incision on medial ankle was made.The necrotic talus was completely removed and the prosthesis was then implanted.The patient was reexamined in the outpatient department 3, 6, and 12 months after surgery.Primary outcome measures were the American Orthopaedic Foot and Ankle Society(AOFAS) ankle-hind foot score,visual analogue scale(VAS) and ankle range of motion.Changes in imaging data and plantar pressure were also assessed.Repeated measures analysis of variance and paired-t test were used to compare the data. Results: The talus prosthesis measure preoperatively was completely consistent with that contralateral healthy talus and there was no operation-related complication. All the wounds healed primarily. The patients were followed up effectively for 23.17 months (range:12 to 48 months).The preoperative dorsiflexion of patients was (7.6±5.7)°,it increased to(14.2±6.6)° at 12 month after surgery (t=-2.67,P=0.03).The plantar flexion increased from (22.0±9.9)°preoperatively to (29.2±8.7)° at 12 month after surgery (t=-8.95,P<0.01).Preoperative AOFAS ankle-hind foot score was 26.3±6.6,and it increased to 70.1±2.2,76.0±3.4 and 79.3±4.2 at 3 month,6 month and 12 month after surgery(F=56.81,P<0.01);Pre-operative VAS was[M(Q_R)]3.0(0.8),and it increased to 2.5(1.0),1.5(1.0),1.0(1.0)at 3 month,6 month and 12 month after surgery(F=20.00,P<0.01).At the last follow-up,imaging reexamination showed that the prosthesis of all patients were in stable position with no sign of subsidence.No secondary ankle fusion or revision was required.The talus height increased from (27.6±6.0)mm preoperatively to (34.6±3.5)mm (t=-2.94,P<0.01).The plantar pressure showed that the maximum pressure on the healthy ankle was(629.9±26.1)N,and that on the affected side was(521.4±14.4)N.The pressure on the healthy ankle was(350.6±29.6)N,and that on the necrotic side was (212.3±9.7)N.The load on the contralateral forefoot was(38.1±2.8)% and that on the necrotic side was(11.5±2.0)%.The load on the contralateral hindfoot was (24.6±2.5)% and that on the necrotic side was (21.1±1.8)%. Conclusions: The custom-made 3D printed talus prosthesis could restore the talus anatomy,recover the ankle joint function,relieve the pain of patients and improve the life quality of patients.The effect on plantar pressure is mainly achieved by adjusting the center of gravity of plantar pressure backwards and the increase of weight bearing of the healthy foot.

[Clinicopathological features of adenocarcinoma of the rete testis]

Objective: To investigate the clinicopathological features, immunophenotype, and differential diagnosis of adenocarcinoma of the rete testis. Methods: Four adenocarcinoma cases of the rete testis diagnosed at West China Hospital, Chengdu, China (3 cases, including 2 consultation cases) and the First Affiliated Hospital of Fujian Medical University, Fuzhou, China (1 case) between January 2009 and December 2017 were included. Their clinical, morphologic and immunohistochemical features were analyzed using histological analysis and immunohistochemical staining. Related literature was reviewed to reveal the characteristics of this tumor. Results: The 4 patients' age range was 26-64 years. The maximum diameters of the tumors were 3.0 and 4.5 cm in 2 cases, respectively. On gross examination, adenocarcinomas of the rete testis appeared as a solid, white to gray or tan to yellow mass that raised at the hilum of the testis. Microscopically, all tumors showed multiple histologic patterns, including corded/trabecular (4/4), glandular, nested, sarcomatoid (3/4), solid (2/4), papillary, cribriform, and slit-like (1/4). Three types of adenocarcinoma cells included cuboidal to columnar (4/4), polygonal (4/4) and spindle-shaped (2/4) with pale eosinophilic and clear cytoplasm. The tumor cell nuclei appeared moderately to markedly atypical and pleomorphic, with a various number of mitoses. Transition from benign to malignant rete epithelium was seen in all cases. Eosinophilic hyaloid globules were found in 1 case. On immunohistochemical study, the tumor cells were diffusely, strongly positive for CKpan (4/4), EMA (4/4), Ber-EP4 (3/3) and CAⅨ(2/2), and focally positive for CK7 (4/4), vimentin (4/4), CD10 (4/4), PAX8 (3/3), PAX2 (3/3). The Ki-67 proliferative index was all>50% (4/4). The prognosis was poor. Two of the 3 patients died within 1 year after the surgical resection. Conclusions: Adenocarcinoma of the rete testis is a rare malignant tumor with several histologic patterns. Transition from benign to malignant rete epithelium is an important diagnostic clue. Detailed clinical history, tumor growth site and immunohistochemistry are helpful for its diagnosis and differential diagnosis.

Contributions of epiphytic microbiota on the fermentation characteristics and microbial composition of ensiled six whole crop corn varieties

AIMS

The present study is aimed to reveal the variations in epiphytic microbial composition among six whole crop corn (WCC) varieties and their contributions on ensiling characteristics and microbial composition of WCC silage.

METHODS AND RESULTS

Six WCC varieties (JS06, YS23, BS20, JS39, JS40 and JS26) were ensiled for 90 days. All WCC varieties were well fermented with low pH value (<4·0) and high LA (73·6-124 g kg^-1 DM, dry matter) concentration. Of six varieties, JS40 had the highest LA (124 g kg^-1 DM) concentration, which was supported by highest relative abundance of Lactobacillus. Pantoea was the most dominant epiphytic bacteria in all fresh WCC varieties; however, the secondary dominant genera among six WCC were absolutely difference. Lactobacillus became predominant genus in 90-day silages except YS23. YS23 kept the more bacterial genus from fresh to 90-day silages than other silages, meanwhile Acinetobacter and Enterobacter were the dominant bacteria in YS23 silages.

CONCLUSIONS

Among six WCC varieties, JS40 silage had the highest LA. The variations in epiphytic microbiomes among fresh WCC affected terminal microbial community of 90-day silages. There were differences in fermentation characteristics among six WCC varieties, which might be partly attributed to variations in epiphytic microbiomes among fresh WCC.

SIGNIFICANCE AND IMPACT OF THE STUDY

The study not only enriches the research on microbial communities of plant phyllosphere but also provides theoretical basis for selecting WCC varieties and inoculants for the forage production.

Characterization and identification of cellulase-producing Enterococcus species isolated from Tibetan yak (Bos grunniens) rumen and their application in various forage silages

AIMS

Cellulase-producing Enterococcus species isolated from the rumen of Tibetan yak (Bos grunniens) were characterized, and their combined effects on the silage quality of various forages were studied.

METHODS AND RESULTS

The two isolated strains with high cellulolytic potential were identified as Enterococcus faecalis (EF85) and E. faecium (EF83) by 16S rRNA sequencing. Both EF85 and EF83 could grow well at 15-55°C, pH 3·0-6·0 and in 3·0-6·5% NaCl. The cellulase secreted by EF85 and EF83 showed good stability at temperatures from 20 to 45°C and pH from 4·5 to 7·0. A commercial inoculant (CLP), a commercial cellulase (CE) and the two cellulolytic strains (EF85 + EF83) were added to whole-crop corn, sweet sorghum and Napier grass ensiling for 120 days respectively. In Napier grass silage, all inoculants significantly increased lactic acid content and ratio of lactic to acetic acid and decreased pH, butyric acid and ammonia nitrogen contents. The acid detergent fibre and cellulose contents in EF85 + EF83 treatment were significantly lower than those in the other treatments. In whole-crop corn and sweet sorghum silages, all additives had no significant effect on the fermentation quality, while CE and EF85 + EF83 markedly enhanced cellulose degradation and increased free sugar content.

CONCLUSION

The combined inoculation of the cellulolytic strain EF85 and EF83 to various forages reduced the fibre content of the resulting silages.

SIGNIFICANCE AND IMPACT OF THE STUDY

Few studies involved inoculation of silage with Enterococcus species in different forage types. The isolated cellulolytic strains of E. faecalis EF85 and E. faecium EF83 could be a great alternative for commercial inoculants and enzymes in silage production.

EmhR is an indole-sensing transcriptional regulator responsible for the indole-induced antibiotic tolerance in Pseudomonas fluorescens

Indole is well known as an interspecies signalling molecule to modulate bacterial physiology; however, it is not clear how the indole signal is perceived and responded to by plant growth promoting rhizobacteria (PGPR) in the rhizosphere. Here, we demonstrated that indole enhanced the antibiotic tolerance of Pseudomonas fluorescens 2P24, a PGPR well known for its biocontrol capacity. Proteomic analysis revealed that indole influenced the expression of multiple genes including the emhABC operon encoding a major multidrug efflux pump. The expression of emhABC was regulated by a TetR-family transcription factor EmhR, which was demonstrated to be an indole-responsive regulator. Molecular dynamics simulation showed that indole allosterically affected the distance between the two DNA-recognizing helices within the EmhR dimer, leading to diminished EmhR-DNA interaction. It was further revealed the EmhR ortholog in Pseudomonas syringae was also responsible for indole-induced antibiotic tolerance, suggesting this EmhR-dependent, indole-induced antibiotic tolerance is likely to be conserved among Pseudomonas species. Taken together, our results elucidated the molecular mechanism of indole-induced antibiotic tolerance in Pseudomonas species and had important implications on how rhizobacteria sense and respond to indole in the rhizosphere.

[Study on the clinical significance and correlation of arginase-1 and inducible nitric oxide synthase expression in hepatocellular carcinoma]

Objective: To investigate the clinical significance and correlation of arginase 1 (Arg-1) and inducible nitric oxide synthase (iNOS) expression in hepatocellular carcinoma (HCC). Methods: The expression of Arg-1and iNOS in 146 cases of hepatocellular carcinoma tissues and corresponding adjacent tissues was detected by immunohistochemistry. The clinicopathological characteristics and the correlation between the expressions and prognosis were determined by chi square test, Spearman's rank correlation, Kaplan-Meier survival analysis and Cox regression analysis. Results: The positive rates of Arg-1 and iNOS were 18.7% (23/123) and 37.0% (54/146), respectively, which was significantly lower than the adjacent tissues [100%(146/146) and 93.8% (137/146)] and the difference was statistically significant (χ (2) = 212.521, P < 0.01, χ (2) = 104.276, P < 0.01). There was a positive correlation between the both expression (r = 0.331, P < 0.01). Arg-1 low expression was correlated with preoperative serum alpha-fetoprotein (AFP) level, tumor size, differentiation degree, histological types and Edmondson's grade. iNOS low expression was correlated with the differentiation degree and Edmondson's grade (P < 0.05). Kaplan Meier survival analysis showed that in patients with recurrence-free survival (RFs), Arg-1 (+) group > Arg-1 (-) group and Arg-1 (+) iNOS (+) group > Arg-1 (+) iNOS (-) group > Arg-1 (-) iNOS (-) group (P < 0.05). Cox multivariate analysis showed that age, tumor size, Edmondson's grade, vascular tumor emboli were significantly correlated with RFs (P < 0.05). Conclusion: There is a positive correlation between Arg-1 and iNOS expressions in HCC, and both may reflect the HCC malignant degree. The reduced/absent expression of both may participate in the occurrence and development of HCC. The combined detection of Arg-1 and iNOS on HCC may have certain significance for the judgment of differentiation degree and prognosis.

Bacterial type II toxin-antitoxin systems acting through post-translational modifications

The post-translational modification (PTM) serves as an important molecular switch mechanism to modulate diverse biological functions in response to specific cues. Though more commonly found in eukaryotic cells, many PTMs have been identified and characterized in bacteria over the past decade, highlighting the importance of PTMs in regulating bacterial physiology. Several bacterial PTM enzymes have been characterized to function as the toxin component of type II TA systems, which consist of a toxin that inhibits cell growth and an antitoxin that protects the cell from poisoning by the toxin. While TA systems can be classified into seven types based on nature of the antitoxin and its activity, type II TA systems are perhaps the most studied among the different TA types and widely distributed in eubacteria and archaea. The type II toxins possessing PTM activities typically modify various cellular targets mostly associated with protein translation and DNA replication. This review mainly focuses on the enzymatic activities, target specificities, antitoxin neutralizing mechanisms of the different families of PTM toxins. We also proposed that TA systems can be conceptually viewed as molecular switches where the 'on' and 'off' state of the system is tightly controlled by antitoxins and discussed the perspective on toxins having other physiologically roles apart from growth inhibition by acting on the nonessential cellular targets.

Protective effects of Lactobacillus plantarum strain P1 against toxicity of the environmental oestrogen di-n-butyl phthalate in rats

Phthalates are contaminants widely distributed in the food-chain, and they are considered as important environmental oestrogens in our lives. In the present study, eight strains of lactic acid bacteria were isolated for their ability to adsorb di-n-butyl-phthalate (DBP), and one of the strains, Lactobacillus plantarum strain P1, was selected for more detailed analyses of its phthalate adsorption capacity in vitro. This study also evaluated the in vivo protective effects of strain P1 against DBP toxicity in rats. Sixteen rats were divided into four groups, and animals received by oral gavage every other day for a period of one month saline with or without strain P1 at 2×10¹¹ cfu/kg followed by maize oil with or without DBP (50 mg/kg). Strain P1 could adsorb more DBP than saline alone, and the concentration of mono-n-butyl phthalate in urine was decreased in animals receiving P1. Furthermore, oestrogenic effects of the different treatments were assessed through counting of sperm and observation of testis, and strain P1 could protect the sexual organs of male rats. Our results suggested that P1 is effective against phthalate toxicity due to its ability to adsorb DBP in vivo and could be considered as a new dietary therapeutic strategy against environmental phtalate toxicity.

Effect of sorbic acid and dual-purpose inoculants on the fermentation quality and aerobic stability of high dry matter rice straw silage

AIMS

This study aimed to evaluate the feasibility of sorbic acid (SA) as a silage additive and its effects on fermentation quality and aerobic stability of high dry matter (DM) silage.

METHODS AND RESULTS

High DM rice straw was ensiled with distilled water (C), 1 × 10⁶  CFU per gram fresh weight (FW) Lactobacillus plantarum and 1 × 10⁶  CFU per gram FW Lactobacillus buchneri (LP+LB) or SA for 45 days with a subsequent aerobic stability test. After ensiling, LP+LB silage had the highest lactic acid (LA) content and the lowest pH value, whereas SA silage had the highest DM and water-soluble carbohydrate (WSC) contents, and the lowest ethanol and ammonia nitrogen (NH₃ -N) contents among all silages (P < 0·001). Compared to C silage, SA significantly (P < 0·01) reduced the counts of yeasts but not lactic acid bacteria (LAB). During 6-day aerobic exposure, the continuous pH increase and LA decrease were observed in C and LP+LB silages, and there was no significant change in pH, DM, NH₃ -N and WSC contents of SA silage over the whole aerobic exposure. The SA addition slowed the decline of LA and acetic acid (AA) contents as well as the growth of yeasts and aerobic bacteria under aerobic exposure.

CONCLUSION

In this study, L. buchneri could not function in high DM rice straw silage while SA effectively improved both the fermentation quality and aerobic stability.

SIGNIFICANCE AND IMPACT OF THE STUDY

The SA was more effective than dual-purpose inoculants to improve the aerobic stability of high DM rice straw silage. Thus, SA can be served as a potential antifungal additive for silage with high DM.

Childhood COVID-19: a multicentre retrospective study

Objectives

To investigate the clinical and epidemiological characteristics of paediatric patients with coronavirus disease-19 (COVID-19).

Methods

Paediatric patients diagnosed with COVID-19 between January 15 and March 15, 2020, from seven hospitals in Zhejiang Province, China, were collected retrospectively and analysed.

Results

Thirty-two children with COVID-19, ranging in age from 3 months to 18 years, were enrolled. Family aggregation occurred in 87.5% of infant and preschool-aged children (7/8), and also school-aged children (14/16), but in only 12.5% (1/8) of adolescents (p < 0.05, p < 0.001). Most of these patients had mild symptoms: mainly fever (20/32) followed by cough (10/32) and fatigue (4/32). The average durations of viral RNA in respiratory samples and gastrointestinal samples were 15.8 d and 28.9 d, respectively. Detox duration in faeces decreased with age: 39.8 d, 27.5 d and 20.4 d in infants and preschool children, school children, and adolescents respectively (p_{0–6, –18} <0.01, p_{0–6, –14} <0.05). Pneumonia was found in 14 children, but there was no statistical significance in the incidence of pneumonia between different age groups. Thirty patients were treated with antiviral drugs, and all patients were stable and gradually improved after admission.

Conclusions

Most children with COVID-19 had a mild process and a good prognosis. More attention should be paid to investigation of household contact history in the diagnosis of COVID-19 in young children. Viral RNA lasts longer in the gastrointestinal system than in the respiratory tract, especially in younger children.

Winter warming in Alaska accelerates lignin decomposition contributed by Proteobacteria

BACKGROUND

In a warmer world, microbial decomposition of previously frozen organic carbon (C) is one of the most likely positive climate feedbacks of permafrost regions to the atmosphere. However, mechanistic understanding of microbial mediation on chemically recalcitrant C instability is limited; thus, it is crucial to identify and evaluate active decomposers of chemically recalcitrant C, which is essential for predicting C-cycle feedbacks and their relative strength of influence on climate change. Using stable isotope probing of the active layer of Arctic tundra soils after depleting soil labile C through a 975-day laboratory incubation, the identity of microbial decomposers of lignin and, their responses to warming were revealed.

RESULTS

The β-Proteobacteria genus Burkholderia accounted for 95.1% of total abundance of potential lignin decomposers. Consistently, Burkholderia isolated from our tundra soils could grow with lignin as the sole C source. A 2.2 °C increase of warming considerably increased total abundance and functional capacities of all potential lignin decomposers. In addition to Burkholderia, α-Proteobacteria capable of lignin decomposition (e.g. Bradyrhizobium and Methylobacterium genera) were stimulated by warming by 82-fold. Those community changes collectively doubled the priming effect, i.e., decomposition of existing C after fresh C input to soil. Consequently, warming aggravates soil C instability, as verified by microbially enabled climate-C modeling.

CONCLUSIONS

Our findings are alarming, which demonstrate that accelerated C decomposition under warming conditions will make tundra soils a larger biospheric C source than anticipated. Video Abstract.

THU0544 MULTIMODAL PHOTOACOUSTIC/ULTRASONIC IMAGING SYSTEM: A NEW IMAGING METHOD FOR EVALUATING RA

Background:

Photoacoustic imaging (PAI), a new imaging technique which can be integrating with ultrasound (US) imaging, has shown potential in visualizing small joints. We have developed a multimodal photoacoustic/ultrasound (PA/US) imaging system, equipped with a handheld probe, which can provide dual-wavelength PA/US imaging to identify the micro-vessels of the inflamed articular regions and measure the oxygenation level of human inflamed synovium.

Objectives:

To validate the potential value for RA of the imaging system.

Methods:

A total of 32 RA patients received PA/US examination on seven small joints (MCP2, MCP3, PIP2, PIP3, MTP2, MTP5, and wrist of the clinically dominant side). The 0-3 score was used to semi-quantify the PA and PD signals of the inflammatory articular lesions, and the sums of PA and PD scores (PA-sum and PD-sum) were utilized. The relative oxygen saturation (SO2) values of the inflamed regions were measured by calculating the ratio of PA signals at the wavelength of 750nm and 830nm. All the patients were classified to 3 PA+SO2 patterns (Pattern 1: no or minimal PA signals; Pattern 2: evident PA signals and hyperoxia; Pattern 3: evident PA signals and hypoxia). The correlations between imaging scores and laboratory data, as well as clinical scoring systems were assessed.

Results:

A total of 32 patients of RA were recruited aged from 25-71 years-old were examined. PD-sum had moderate correlation with the clinical scores (r=0.529, 0.546, 0.490, 0.493 for DAS28ESR, DAS28CRP, SDAI, CDAI), moderate correlations with TJC (r=0.575) and SJC (r=0.491), fair correlation with VAS (r=0.239), poor correlation with PGA (r=0.153), and moderate correlation with EGA (r=0.457). The PA-sum had substantial correlations with the clinical scores (r= 0.699, 0.746, 0.723, 0.736 for DAS28ESR, DAS28CRP, SDAI, CDAI), substantial correlations with TJC (r=0.787) and SJC (r=0.694), moderate correlations with VAS (r=0.544) and PGA (r=0.529), and substantial correlation with EGA (r=0.708).

Ten patients were classified as Pattern 1, 12 as Pattern 2, 9 as Pattern 3. The PA+ SO2 patterns presented substantial correlations with the clinical scores (DAS28ESR r=0.690, DAS28CRP r=0.782, SDAI r=0.805, CDAI r=0.799, SJC r=647, TJC r=0.676, respectively), substantial correlation with VAS (r=0.714), and moderate correlation with PGA (r=0.476) and EGA (r=0.502). Significant differences between those who were classified as hypoxia and hyperoxia with evident PA signals, were detected in VAS (p=0.020) and PGA (p=0.026).

Conclusion:

The PA-sum scores and the PA+SO2 patterns can be utilized as objective imaging parameters reflecting the disease activity of RA. PAI may serve as a supplement to conventional US examinations for RA patients.

References:

[1]Backhaus, M., et al., Evaluation of a novel 7-joint ultrasound score in daily rheumatologic practice: a pilot project. Arthritis Rheum, 2009. 61(9): p. 1194-201.

[2]Colebatch, A.N., et al., EULAR recommendations for the use of imaging of the joints in the clinical management of rheumatoid arthritis. Ann Rheum Dis, 2013. 72(6): p. 804-14.

Figure 1.

the photo of the multimodal PA/US imaging system

Figure 2.

an example of the PA/US imaging

Disclosure of Interests:

Chenyang Zhao: None declared, Qian Wang: None declared, Xixi Tao: None declared, Chen Yu: None declared, Sirui Liu: None declared, Mengtao Li: None declared, Xinping Tian: None declared, Zhenhong Qi: None declared, Jianchu Li: None declared, Fang Yang: None declared, Lei Zhu: None declared, Xiaofeng Zeng Consultant of: MSD Pharmaceuticals, Meng Yang: None declared, Yuxin Jiang: None declared

Precise promoter integration improves cellulose bioconversion and thermotolerance in Clostridium cellulolyticum

Lignocellulose has been used for production of sustainable biofuels and value-added chemicals. However, the low-efficiency bioconversion of lignocellulose greatly contributes to a high production cost. Here, we employed CRISPR-Cas9 editing to improve cellulose degradation efficiency by editing a regulatory element of the cip-cel gene cluster in Clostridium cellulolyticum. Insertion of a synthetic promoter (P4) and an endogenous promoter (P2) in the mspI-deficient parental strain (Δ2866) created chromosomal integrants, P4-2866 and P2-2866, respectively. Both engineered strains increased the transcript abundance of downstream polycistronic genes and enhanced in vitro cellulolytic activities of isolated cellulosomes. A high cellulose load of 20 g/L suppressed cellulose degradation in the parental strain in the first 150 h fermentation; whereas P4-2866 and P2-2866 hydrolyzed 29% and 53% of the cellulose, respectively. Both engineered strains also demonstrated a greater growth rate and a higher cell biomass yield. Interestingly, the Δ2866 parental strain demonstrated better thermotolerance than the wildtype strain, and promoter insertion further enhanced thermotolerance. Similar improvements in cell growth and cellulose degradation were reproduced by promoter insertion in the wildtype strain and a lactate production-defective mutant (LM). P2 insertion in LM increased ethanol titer by 65%. Together, the editing of regulatory elements of catabolic gene clusters provides new perspectives on improving cellulose bioconversion in microbes.

Warming-induced permafrost thaw exacerbates tundra soil carbon decomposition mediated by microbial community

BACKGROUND

It is well-known that global warming has effects on high-latitude tundra underlain with permafrost. This leads to a severe concern that decomposition of soil organic carbon (SOC) previously stored in this region, which accounts for about 50% of the world's SOC storage, will cause positive feedback that accelerates climate warming. We have previously shown that short-term warming (1.5 years) stimulates rapid, microbe-mediated decomposition of tundra soil carbon without affecting the composition of the soil microbial community (based on the depth of 42684 sequence reads of 16S rRNA gene amplicons per 3 g of soil sample).

RESULTS

We show that longer-term (5 years) experimental winter warming at the same site altered microbial communities (p < 0.040). Thaw depth correlated the strongest with community assembly and interaction networks, implying that warming-accelerated tundra thaw fundamentally restructured the microbial communities. Both carbon decomposition and methanogenesis genes increased in relative abundance under warming, and their functional structures strongly correlated (R² > 0.725, p < 0.001) with ecosystem respiration or CH₄ flux.

CONCLUSIONS

Our results demonstrate that microbial responses associated with carbon cycling could lead to positive feedbacks that accelerate SOC decomposition in tundra regions, which is alarming because SOC loss is unlikely to subside owing to changes in microbial community composition. Video Abstract.

Comparison of microRNAs in adipose and muscle tissue from seven indigenous Chinese breeds and Yorkshire pigs

Elucidation of the pig microRNAome is essential for interpreting functional elements of the genome and understanding the genetic architecture of complex traits. Here, we extracted small RNAs from skeletal muscle and adipose tissue, and we compared their expression levels between one Western breed (Yorkshire) and seven indigenous Chinese breeds. We detected the expression of 172 known porcine microRNAs (miRNAs) and 181 novel miRNAs. Differential expression analysis found 92 and 12 differentially expressed miRNAs in adipose and muscle tissue respectively. We found that different Chinese breeds shared common directional miRNA expression changes compared to Yorkshire pigs. Some miRNAs differentially expressed across multiple Chinese breeds, including ssc-miR-129-5p, ssc-miR-30 and ssc-miR-150, are involved in adipose tissue function. Functional enrichment analysis revealed that the target genes of the differentially expressed miRNAs are associated mainly with signaling pathways rather than metabolic and biosynthetic processes. The miRNA-target gene and miRNA-phenotypic traits networks identified many hub miRNAs that regulate a large number of target genes or phenotypic traits. Specifically, we found that intramuscular fat content is regulated by the greatest number of miRNAs in muscle tissue. This study provides valuable new candidate miRNAs that will aid in the improvement of meat quality and production.

[A comparative study of the calcaneal closing-wedge calcaneal osteotomy versus posterior-superior prominence removal in both sides with Haglund syndrome]

Objective: To compare the clinical outcome of removal of calcaneal posterior-superior prominence and that of calcaneal closing-wedge osteotomy for Haglund syndrome. Methods: From February 2009 to July 2014, 36 patients with Haglund syndrome were included.They were divided into two groups, and each group included 18 patients and underwent removal of calcaneal posterior-superior prominence and calcaneal closing-wedge osteotomy respectively.They were evaluated preoperatively and after 6 , 12 months and 24 months postoperatively by American Orthopedic Foot & Ankle Society (AOFAS) score, VAS score, VISA-A questionnaire and Maryland Foot Score.Fowler-Philip angle and calcaneal posterior slope of the two groups were compared preoperatively and after 6 months.All data were analysis utilizing SPSS 18.0. Results: At six months of follow-up, the weight-bearing lateral X-rays reveals that removal of calcaneal posterior-superior prominence did not change Fowler-Philip angle and calcaneal posterior slope and calcaneal closing-wedge osteotomy decreased Fowler-Philip angle and calcaneal posterior slope significantly[from preoperation (56.5±5.4)°, (120.0±1.3)°to postoperation (48.4±4.6)°, (109.0±5.3)°]. At six months of follow-up, the AOFAS score, VAS score, VISA-A questionnaire and Maryland Foot Score were worse in the wedge calcaneal osteotomy group.At twelve months of follow-up, no significant difference (P>0.05)was found between the two groups in terms of VAS score, and Maryland Foot Score, while the AOFAS score, and VISA-A questionnaire in the wedge calcaneal osteotomy group were better than those of posterior-superior prominence removal group.At twenty-four months of follow-up, the AOFAS score, VAS score, VISA-A questionnaire and Maryland Foot Score were better in the wedge calcaneal osteotomy group (P<0.05). Conclusions: Both the two surgical methods are effective for Haglund syndrome.Calcaneal closing-wedge osteotomy decreased Fowler-Philip angle and calcaneal posterior slope of calcaneus and its clinical outcome appears better than that removal of calcaneal posterior-superior prominence.

The antitoxin MqsA homologue in Pseudomonas fluorescens 2P24 has a rewired regulatory circuit through evolution

The mqsRA operon encodes a toxin-antitoxin pair that was characterized to participate in biofilm and persister cell formation in Escherichia coli. Notably, the antitoxin MqsA possesses a C-terminal DNA-binding domain that recognizes the [5'-AACCT(N)_2-4 AGGTT-3'] motif and acts as a transcriptional regulator controlling multiple genes including the general stress response regulator RpoS. However, it is unknown how the transcriptional circuits of MqsA homologues have changed in bacteria over evolutionary time. Here, we found mqsA in Pseudomonas fluorescens (PfmqsA) is acquired through horizontal gene transfer and binds to a slightly different motif [5'-TACCCT(N)₃ AGGGTA-3'], which exists upstream of the PfmqsRA operon. Interestingly, an adjacent GntR-type transcriptional regulator, which was termed AgtR, is under negative control of PfMqsA. It was further demonstrated that PfMqsA reduces production of biofilm components through AgtR, which directly regulates the pga and fap operons involved in the synthesis of extracellular polymeric substances. Moreover, through quantitative proteomics analysis, we showed AgtR is a highly pleiotropic regulator that influences up to 252 genes related to diverse processes including chemotaxis, oxidative phosphorylation and carbon and nitrogen metabolism. Taken together, our findings suggest the rewired regulatory circuit of PfMqsA influences diverse physiological aspects of P. fluorescens 2P24 via the newly characterized AgtR.