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ABSTRACT: Bacillus licheniformis is one of the major spore-forming bacteria with great genotypic diversity in raw milk, dairy ingredients, and final dairy products; it is found throughout the dairy-processing continuum. Although being widely used as a probiotic strain, this species also serves as a potential risk in the dairy industry based on its roles in foodborne illness and dairy spoilage. Biofilm formation of B. licheniformis, combined with the heat resistance of its spores, make it impossible to prevent the presence of B. licheniformis in final dairy products by using traditional cleaning and disinfection procedures. Despite the extensive efforts to identify B. licheniformis in various dairy samples, no reviews have been written on both hazards and benefits of this sporeformer. This review discusses the prevalence of B. licheniformis from raw milk to commercial dairy products, biofilm formation and spoilage potential of B. licheniformis, and possible prevention methods. In addition, the potential benefits of B. licheniformis in the dairy industry are also summarized.

ABSTRACT: Biofilm formation is usually affected by many environmental factors, including divalent cations. The purpose of the current work was to analyze how calcium (Ca2+) affects the biofilm formation of dairy Pseudomonas fluorescens isolates by investigating their growth, swarming motility, biofilm-forming capacity, extracellular polymeric substance production, and biofilm structures. Moreover, the regulation mechanism of Ca2+ involved in its biofilm formation was explored through RNA-sequencing analysis. This work revealed that supplementation of 5, 10, 15, and 20 mM Ca2+ significantly reduced the swarming motility of P. fluorescens strains (P.F2, P.F4, and P.F17), but the biofilm-forming ability and polysaccharide production were increased after the supplementation of 5 and 10 mM Ca2+. By the supplementation of Ca2+, complex structures with more cell clusters glued together in P. fluorescens P.F4 biofilms were confirmed by scanning electron microscopy, and increased biomass and coverage of P. fluorescens P.F4 biofilms were observed by confocal laser scanning microscopy. In addition, RNA-sequencing results showed that P. fluorescens P.F4 showed a transcriptional response to the supplementation of 10 mM Ca2+, and a total of 137 genes were significantly expressed. The differential genes were represented in 4 upregulated Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways (nonribosomal peptide structures, quorum sensing, biosynthesis of siderophore group nonribosomal peptides, and phenylalanine metabolism), and 4 downregulated KEGG pathways (flagellar assembly, amino sugar and nucleotide sugar metabolism, nitrotoluene degradation, and cationic antimicrobial peptide resistance). The results indicate that Ca2+ might serve as an enhancer to substantially trigger the biofilm formation of dairy P. fluorescens isolates in the dairy industry.

Objective: Previously, our group screened a strain of Lactobacillus casei YZU01 that could efficiently remove patulin from apple juice. This article aimed to study the effect of L. casei YZU01 on the quality of apple juice during the removal of patulin from apple juice. Methods: The quality parameters of apple juice, including organic acids (citric acid, tartaric acid, fumaric acid, acetic acid and L-malic acid) and sugar content (glucose and galactose), acidity, non-enzymatic browning index, light transmittance, and color parameter, were assessed in three groups: commercial apple juice (CAJ), apple juice supplemented with patulin (CAJ-Patulin), and apple juice supplemented with patulin after degradation by L. casei YZU01 (CAJ-Patulin-L. casei YZU01). This analysis was conducted using high performance liquid chromatography (HPLC), pH meter, UV spectrophotometer, and colorimeter. Results: The content of citric acid, tartaric acid, fumaric acid and acetic acid in the group of CAJ-Patulin-L. casei YZU01 was increased from 0.18, 2.3, 0.12, and 0.00 g/kg to 2.11, 3.4, 0.15, and 0.66 g/kg, respectively. However, the content of L-malic acid, glucose and galactose in the group of CAJ-Patulin-L. casei YZU01 was decreased from 7.31, 38.59, and 67.55 g/kg to 5.26, 1.59 and 28.37 g/kg, respectively. The change of sugar and acid contents in the group of CAJ-Patulin-L. casei YZU01 had little effect on the acidity of apple juice. Furthermore, L. casei YZU01 treatment would not cause non-enzymatic browning reaction and had not adverse effects on the color of apple juice, but it would cause a fluctuation in light transmittance. In addition, after 72 hours of degradation, L. casei YZU01 had little effect on the L* and b* value of apple juice, but slightly increased the a* value, which represented that the green color of apple juice became lighter. In conclusion, the sugar and acid contents of apple juice were changed after treatment with L. casei YZU01, but no non-enzymatic browning reaction and color change was observed.

A simple, rapid and novel method involving ultrahigh-performance liquid chromatography-electrospray ionization tandem triple quadrupole mass spectrometry (UHPLC-ESI–MS/MS) was developed to simultaneously detect erythromycin, its major metabolite and clarithromycin in chicken tissues (muscle, liver and kidney) and eggs (whole egg, albumen and yolk). Samples were extracted using acetonitrile–water (80:20, v/v), and a Cleanert MAS-Q cartridge was used to perform quick, easy, cheap, effective, rugged, and safe (QuEChERS) purification. The average recoveries were 87.78–104.22 %, and the corresponding intraday and interday relative standard deviations were less than 7.10 %. The decision limits and detection capabilities of the chicken tissues and eggs were 2.15–105.21 μg/kg and 2.26–110.42 μg/kg, respectively. For chicken tissues and eggs, the limits of detection and limits of quantification were 0.5 μg/kg and 2.0 μg/kg, respectively. The proposed method was successfully employed to analyse real samples, demonstrating its applicability.

ABSTRACT: Biofilms formed by pathogenic or spoilage microorganisms have become serious issues in the dairy industry, as this mode of life renders such microorganisms highly resistant to cleaning-in-place (CIP) procedures, disinfectants, desiccation, and other control strategies. The advent of omics techniques, especially the integration of different omics tools, has greatly improved our understanding of the features of microbial biofilms, and provided in-depth knowledge on developing effective methods that are directly against deleterious biofilms. This review provides novel insights into the single use of each omics tool and the application of multiomics tools to unravel the mechanisms of biofilm formation, specific molecular phenotypes exhibited by biofilms, and biofilm control strategies. Challenges and future perspective on the integration of omics tools for biofilm studies are also addressed.

The effect of adding a small amount of Ag on the microstructure evolution and superplastic properties of Mg-Y-Er-Zn (WEZ612) alloys was systematically studied. The basal texture of the refined WEZ612 alloy produced by equal channel angular pressing was altered to a non-basal structure upon the addition of Ag. Ag addition also refined the grain size and promoted the formation of a large number of nano-14H-long period stacking ordered phases. Using high-resolution transmission electron microscopy, many nano-precipitated phases were detected on the basal plane of the Mg-Y-Er-Zn-1Ag (WEZ612–1Ag) alloy, The nano-precipitated phases on the basal plane improved the thermal stability of the alloy, lowered the deformation activation energy (Q), and improved the stress sensitivity index (m). At 523 K with a strain rate of 10−2 s−1, the Q value of WEZ612 was higher than that of WEZ612–1Ag (299.14 and 128.5 kJ mol−1, respectively). In contrast, the m value of the WEZ612 alloy (0.16) was lower than that of the WEZ612–1Ag alloy (0.46). At 623 K with a tensile rate of 10−2 s−1, the WEZ612 and WEZ612–1Ag alloys were elongated by 182% and 495%, respectively, with the latter exhibiting high-strain-rate and low-temperature superplasticity. The improved superplasticity of the WEZ612-1Ag alloy is attributed to the nano-precipitated phases, which effectively limit the cavity extension during superplastic deformation.

As a natural cationic peptide, Nisin is capable of widely inhibiting the growth of Gram-positive bacteria. However, it also has drawbacks such as its antimicrobial activity being susceptible to environmental factors. Nano-encapsulation can improve the defects of nisin in food applications. In this study, nisin-loaded egg white protein nanoparticles (AH-NEn) were prepared in fixed ultrasound-mediated under pH 3.0 and 90 °C. Compared with the controls, AH-NEn exhibited smaller particle size (112.5 ± 2.85 nm), smaller PDI (0.25 ± 0.01), larger Zeta potential (24 ± 1.18 mV), and higher encapsulation efficiency (91.82%) and loading capacity (45.91%). The turbidity and Fourier transform infrared spectroscopy (FTIR) results indicated that there are other non-covalent bonding interactions between the molecules of AH-NEn besides the electrostatic forces, which accounts for the fact that it is structurally more stable than the controls. In addition, by the results of fluorescence intensity, differential scanning calorimetry (DSC), and X-ray diffraction (XRD), it was shown that thermal induction could improve the solubility, heat resistance, and encapsulation of nisin in the samples. In terms of antimicrobial function, acid–heat induction did not recede the antimicrobial activity of nisin encapsulated in egg white protein (EWP). Compared with free nisin, the loss rate of bactericidal activity of AH-NEn was reduced by 75.0% and 14.0% following treatment with trypsin or a thermal treatment at 90 °C for 30 min, respectively.

Most metals including Mg alloys have a longstanding dilemma of strength-ductility trade-off, which is hindering their wider applications. In this study, we propose a gradient heterogeneous grain (GHG) structure for evading this trade-off dilemma and ultrasonic severe surface rolling is attempted to construct this novel structure in ZE41 Mg alloy. Here, the GHG structure combine the benefits of gradient structure and heterogeneous grain structure and introduce large microstructural heterogeneities. Compared to the coarse-grain and heterogeneous-grain structured alloys, the GHG structured one exhibits dramatical enhancement in strength, ductility, and strain hardening capability. To the best of our knowledge, its strength becomes much higher than that of common ZE41 Mg alloys at no reduction in ductility. These unique mechanical properties stem from not only the individual contribution of the heterogeneous structure components including the fine/ultrafine grains and deformed coarse grains but also their synergistic effect via hetero-deformation induced strengthening and hardening effects. In summary, our study provides a feasible way to develop new Mg alloys with high strength and good ductility.

A warm equal-channel angular pressing (ECAP) procedure was applied to a new Mg–6.5Y–1.2Er–1.6Zn (WEZ612)–0.5Ag alloy with a long-period stacking ordered (LPSO) phase. The microstructure, superplasticity, and deformation mechanism of the WEZ612–0.5Ag alloy were then systematically investigated. Three different precipitation phases formed in the alloy with trace Ag addition, namely LPSO, γ, and nanoprecipitate phases. A remarkable elongation of 726% was attained at 623 K and a strain rate of 0.01 s−1. The strain rate sensitivity index (m) and activation energy (Q) under these deformation conditions were 0.461 and 133.08 kJ mol−1, respectively. These m and Q values confirm that the primary deformation mechanism of the WEZ612–0.5Ag alloy at 623 K was grain boundary sliding assisted by lattice diffusion. The highly stable LPSO phases, γ precipitates, and nanoprecipitates synergistically improved the superplasticity of the alloy by retarding crack propagation and grain growth and by promoting the basal plane slip.

Nantong Hualushao wine is a special type of traditional Huangjiu, or Chinese yellow wine. It has been added to the list of intangible cultural heritage in Nantong, Jiangsu Province. In this study, the key quality indicators of ten commercial Hualushao wines and five traditional Huangjiu products were determined. The organic acids and sugars were analysed using high-performance liquid chromatography (HPLC), and the colour was measured with a spectrophotometer. By comparing the content of the Hualushao wines and the Huangjiu samples using statistical methods, the differences between these two products were described, and the characteristics of Hualushao wine were clarified. Results revealed that the acetic acid, total sugar, glucose, alcohol, and soluble solid content, as well as the pH value of Hualushao wine, were significantly higher than those of traditional Huangjiu (P

Phlebopus portentosus is an edible and medicinal mushroom with a delicious taste and high nutritional value. The oligosaccharides derived from P. portentosus may be the material basis for its biological activity. The degradation of polysaccharide and the maintenance of its activity after degradation are key steps in related research. This study applied an acid degradation method to prepare P. portentosus refined polysaccharide (PPRP) with a smaller molecular weight, and the optimal hydrolysis conditions determined were a temperature of 80 °C, an acid concentration of 2 mol/L, and a hydrolysis time of 2 h. The polysaccharide structure and immune activity were then further investigated. The results showed that the PPRP comprised two fractions with approximate weights of 61,600 Da and 5500 Da. The monosaccharide composition of PPRP was mannose, rhamnose, glucose, and galactose, with a molar ratio of 1.00: 22.24: 2.93: 1.03. The major functional groups included O-H, C-H, C-O, and C-O-C. The glycosidic bond types were mainly α- and β-glycosidic bonds. Cell experiments demonstrated that PPRP could significantly increase the proliferation of macrophages and enhance the cytotoxicity of NK cells. Moreover, PPRP also significantly promoted the proliferation of B lymphocytes and T lymphocytes, especially at a concentration of 200 μg/mL. This study furnishes scientific evidence underlining the significant potential of PPRP in immune activity, thereby serving as a material basis and scientific bedrock for further investigations into the mechanism of P. portentosus oligosaccharide activity.

Prophages as a part of Staphylococcus aureus genome contribute to the genetic diversity as well as survival strategies of their host. Some S. aureus prophages also have an imminent risk of host cell lysis and become a lytic phage. Nonetheless, interactions among S. aureus prophages, lytic phages, and their hosts, as well as the genetic diversity of S. aureus prophages, remain unclear. We identified 579 intact and 1,389 incomplete prophages in the genomes of 493 S. aureus isolates obtained from the NCBI database. The structural diversity and gene content of intact and incomplete prophages were investigated and compared with 188 lytic phages. Mosaic structure comparison, ortholog group clustering, phylogenetic analysis, and recombination network analysis were performed to estimate genetic relatedness among S. aureus intact prophages, incomplete prophages, and lytic phages. The intact and incomplete prophages harbored 148 and 522 distinct mosaic structures, respectively. The major difference between lytic phages and prophages was the lack of functional modules and genes. Compared to the lytic phages, both the S. aureus intact and incomplete prophages harbored multiple antimicrobial resistance (AMR) and virulence factor (VF) genes. Several functional modules of lytic phages 3_AJ_2017 and 23MRA shared more than 99% nucleotide sequence identity with S. aureus intact (ST20130943_p1 and UTSW_ MRSA_55_ip3) and incomplete prophages (SA3_LAU_ip3 and MRSA_FKTN_ip4); other modules showed little nucleotide sequence similarity. Ortholog and phylogenetic analyses revealed a common gene pool shared between the prophages and lytic Siphoviridae phages. Moreover, most shared sequences existed within intact (43428/137294, 31.6%) and incomplete prophages (41248/137294, 30.0%). Therefore, the maintenance or loss of functional modules in intact and incomplete prophages is key to balance the costs and benefits of large prophages harboring various AMR and VF genes in the bacterial host. The shared identical functional modules between S. aureus lytic phages and prophages are likely to result in the exchange, acquisition, and loss of functional modules, and therefore contribute to their genetic diversity. Moreover, constant recombination events within prophages globally were responsible for the coevolution of lytic phages and their bacterial hosts.

Antrodia cinnamomea is a valuable edible and medicinal mushroom with antitumor, hepatoprotective, and antiviral effects that play a role in intestinal flora regulation. Spore-inoculation submerged fermentation has become the most efficient and well-known artificial culture process for A. cinnamomea. In this study, a specific low-molecular compound named 1,8-cineole (cineole) from Cinnamomum kanehirae Hay was first reported to have remarkably promoted the asexual sporulation of A. cinnamomea in submerged fermentation (AcSmF). Then, RNA sequencing, real-time quantitative PCR, and a literature review were performed to predict the molecular regulatory mechanisms underlying the cineole-promoted sporulation of AcSmF. The available evidence supports the hypothesis that after receiving the signal of cineole through cell receptors Wsc1 and Mid2, Pkc1 promoted the expression levels of rlm1 and wetA and facilitated their transfer to the cell wall integrity (CWI) signal pathway, and wetA in turn promoted the sporulation of AcSmF. Moreover, cineole changed the membrane functional state of the A. cinnamomea cell and thus activated the heat stress response by the CWI pathway. Then, heat shock protein 90 and its chaperone Cdc37 promoted the expression of stuA and brlA, thus promoting sporulation of AcSmF. In addition, cineole promoted the expression of areA, flbA, and flbD through the transcription factor NCP1 and inhibited the expression of pkaA through the ammonium permease of MEP, finally promoting the sporulation of AcSmF. This study may improve the efficiency of the inoculum (spores) preparation of AcSmF and thereby enhance the production benefits of A. cinnamomea.

Foodborne pathogens cause many diseases and significantly impact human health and the economy. Foodborne pathogens mainly include Salmonella spp., Escherichia coli, Staphylococcus aureus, Shigella spp., Campylobacter spp. and Listeria monocytogenes, which are present in agricultural products, dairy products, animal-derived foods and the environment. Various pathogens in many different types of food and water can cause potentially life-threatening diseases and develop resistance to various types of antibiotics. The harm of foodborne pathogens is increasing, necessitating effective and efficient methods for early monitoring and detection. Traditional methods, such as real-time polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and culture plate, are time-consuming, labour-intensive and expensive and cannot satisfy the demands of rapid food testing. Therefore, new fast detection methods are urgently needed. Electrochemical biosensors provide consumer-friendly methods to quickly detect foodborne pathogens in food and the environment and achieve extensive accuracy and reproducible results. In this paper, by focusing on various mechanisms of electrochemical transducers, we present a comprehensive overview of electrochemical biosensors for the detection of foodborne pathogens. Furthermore, the review introduces the hazards of foodborne pathogens, risk analysis methods and measures of control. Finally, the review also emphasizes the recent research progress and solutions regarding the use of electrochemical biosensors to detect foodborne pathogens in food and the environment, evaluates limitations and challenges experienced during the development of biosensors to detect foodborne pathogens and discusses future possibilities.

It is challenging to develop Mg alloys with high strength-ductility synergy and isotropic mechanical properties. An industrial-scale ultrafine-grained (UFG) Mg-10.6Gd-2Ag wt. % alloy with excellent strength-ductility synergy and near-isotropic mechanical behavior was made by an industrial-scale rotary die equal channel angular pressing (RD-ECAP). The microstructure of the UFG alloy involves the primarily submicron α-Mg grains with an average grain size of 760.5 nm and the high-density submicron β phase (Mg5Gd) precipitates (267.8 nm). Room temperature tensile tests results reveal that the UFG alloy exhibits an over three times tensile yield strength, near two times ultimate tensile strength, and more than one and a half times elongation along three orthogonal test directions than the as-cast Mg alloy. The improvement of strength is linked to the effect of the grain boundary strengthening as well as the precipitation strengthening. The enhanced ductility is ascribed to the ultrafine grains with low dislocation density, which provide a degree of dislocation storage capacity and facilitates multiple potential deformation modes. The near-isotropic mechanical behavior stems from the weak texture and multiple deformation modes.

Antrodia cinnamomea is a precious edible and medicinal fungus with activities of antitumor, antivirus, and immunoregulation. Fe2+ was found to promote the asexual sporulation of A. cinnamomea markedly, but the molecular regulatory mechanism of the effect is unclear. In the present study, comparative transcriptomics analysis using RNA sequencing (RNA-seq) and real time quantitative PCR (RT-qPCR) were conducted on A. cinnamomea mycelia cultured in the presence or absence of Fe2+ to reveal the molecular regulatory mechanisms underlying iron-ion-promoted asexual sporulation. The obtained mechanism is as follows: A. cinnamomea acquires iron ions through reductive iron assimilation (RIA) and siderophore-mediated iron assimilation (SIA). In RIA, ferrous iron ions are directly transported into cells by the high-affinity protein complex formed by a ferroxidase (FetC) and an Fe transporter permease (FtrA). In SIA, siderophores are secreted externally to chelate the iron in the extracellular environment. Then, the chelates are transported into cells through the siderophore channels (Sit1/MirB) on the cell membrane and hydrolyzed by a hydrolase (EstB) in the cell to release iron ions. The O-methyltransferase TpcA and the regulatory protein URBS1 promote the synthesis of siderophores. HapX and SreA respond to and maintain the balance of the intercellular concentration of iron ions. Furthermore, HapX and SreA promote the expression of flbD and abaA, respectively. In addition, iron ions promote the expression of relevant genes in the cell wall integrity signaling pathway, thereby accelerating the cell wall synthesis and maturation of spores. This study contributes to the rational adjustment and control of the sporulation of A. cinnamomea and thereby improves the efficiency of the preparation of inoculum for submerged fermentation.

Antrodia cinnamomea is a precious edible and medicinal mushroom with various biological activities, such as hepatoprotection, antitumor, antivirus, immunoregulation, and intestinal flora regulation. However, the wild fruiting bodies of A. cinnamomea are scarce and expensive. Submerged fermentation based on spore inoculation has become the most efficient and popular artificial culture method for A. cinnamomea. In order to complement the mechanism of asexual sporulation of A. cinnamomea in submerged fermentation, and provide a theoretical basis to further improve the sporulation, comparative transcriptomics analysis using RNA-seq and RT-qPCR were conducted on A. cinnamomea mycelia cultured under different nutritional conditions to reveal the regulatory mechanism underlying the asexual sporulation induced by nutrient limitation. The obtained mechanism is as follows: under nitrogen starvation, the corresponding sensors transmit signals to genes, such as areA and tmpA, and promote their expression. Among these genes, AreA has a direct or indirect effect on flbD and promotes its expression, further enhancing the expression of brlA. Meanwhile, TmpA has a direct or indirect effect on brlA and promotes its expression; under carbon starvation, transport protein Rco-3, as a glucose sensor, directly or indirectly transmits signals to brlA and promotes its expression. BrlA promotes the expression of abaA gene, which further enhances the expression of wetA gene, and wetA then directly leads to asexual sporulation and promotes spore maturation; meanwhile, gulC can also promote cell autolysis, which provides energy and raw materials for sporulation.

Non-coding RNAs (ncRNAs) have gained increasing attention as their diverse roles in virulence and environmental stress in Listeria monocytogenes have become clearer. The ncRNA rliB is an atypical member of the CRISPR family, conserved at the same genomic locus in all analyzed L. monocytogenes genomes and also in other Listeria species. In this study, rliB defective mutants (Lm3-22-ΔrliB) were constructed by homologous recombination. The growth cycle of Lm3-22-ΔrliB mutants was slower than that of wild-type Lm3-22. The sensitivity of Lm3-22-ΔrliB to the Listeria phage vB-LmoM-SH3-3 was significantly increased, and the efficiency of plaque formation was enhanced by 128 fold. Compared with wild type, the adhesion and invasion of Lm3-22-ΔrliB decreased significantly (9.3% and 1.33%, respectively). After 4 hours of infection, the proliferation of Lm3-22-ΔrliB in RAW264.7 cells also decreased significantly. Transcription level of invasion-related surface proteins showed that the internalin genes lmo0610 and lm0514, and the peptidoglycan binding protein gene lmo1799 in Lm3-22-ΔrliB were significantly increased. In addition, after interaction with phage, the transcription levels of inlA, lmo0610, lmo1799, lmo2085, and lmo0514 in Lm3-22-ΔrliB cells were significantly upregulated, while inlB was downregulated, compared with Lm3-22 control group with phage treatment. Therefore, rliB deletion effectively regulated the interaction between Listeria and phage, weaken its invasion ability, and provided a new theoretical basis for biocontrol of phage.

The study of bacteriophages is experiencing a resurgence owing to their antibacterial efficacy, lack of side effects, and low production cost. Nonetheless, the interactions between Staphylococcus aureus bacteriophages and their hosts remain unexplored. In this study, whole-genome sequences of 188 S. aureus bacteriophages—20 Podoviridae, 56 Herelleviridae, and 112 Siphoviridae—were obtained from the National Center for Biotechnology Information (NCBI, USA) genome database. A phylogenetic tree was constructed to estimate their genetic relatedness using single-nucleotide polymorphism analysis. Comparative analysis was performed to investigate the structural diversity and ortholog groups in the subdividing clusters. Mosaic structures and gene content were compared in relation to phylogeny. Phylogenetic analysis revealed that the bacteriophages could be distinguished into three lineages (I–III), including nine subdividing clusters and seven singletons. The subdividing clusters shared similar mosaic structures and core ortholog clusters, including the genes involved in bacteriophage morphogenesis and DNA packaging. Notably, several functional modules of bacteriophages 187 and 2368A shared more than 95% nucleotide sequence identity with prophages in the S. aureus strain RJ1267 and the Staphylococcus pseudintermedius strain SP_11306_4, whereas other modules exhibited little nucleotide sequence similarity. Moreover, the cluster phages shared similar types of holins, lysins, and DNA packaging genes and harbored diverse genes associated with DNA replication and virulence. The data suggested that the genetic diversity of S. aureus bacteriophages was likely due to gene replacement, acquisition, and loss among staphylococcal phages, which may have crossed species barriers. Moreover, frequent module exchanges likely occurred exclusively among the subdividing cluster phages. We hypothesize that during evolution, the S. aureus phages enhanced their DNA replication in host cells and the adaptive environment of their host.

Introduction Unhealthy diet has been identified as the number one attributor of total mortality in China, accounting for more than 20% of total deaths. Although the Dietary Approach to Stop Hypertension (DASH) and Mediterranean diets have been proven beneficial in managing cardiovascular risk factors in Western countries, whether healthy diets with similar cardiovascular benefits can be developed that are consistent with Chinese food culture remains unknown.Methods/design The Diet, ExerCIse and CarDiovascular hEalth (DECIDE)-Diet trial is a multicentre, single-blind, randomised controlled feeding trial to evaluate the effect of the Chinese Healthy Heart (CHH) diet, in comparison with the Chinese usual diet, in lowering cardiovascular risk factors among community residents with the increased cardiovascular risk. A total of 360 adults aged between 25 and 75 years old and with systolic blood pressure between 130 and 159 mm Hg will be recruited from four centres located in four areas representing four major Chinese cuisines: Beijing, Shanghai, Guangzhou and Chengdu. After 1 week of run-in period with local usual diet, the compliant participants will be randomised to the intervention group with the CHH diet or the control group with the usual local diet, on a 1:1 ratio, for 4 weeks. Body weight of study participants will be maintained during the entire study period. The primary outcome is the change in SBP from the baseline to the end of the study. DECIDE-Diet trial will be the first randomised controlled feeding trial to evaluate the effect of a CHH diet in lowering cardiovascular risk factors. This trial will provide compelling evidence on the CHH diet in effect of improving cardiovascular health among Chinese food consumers all around the world.Ethics and dissemination This trial adheres to the Declaration of Helsinki and guidelines of Good Clinical Practice. Signed informed consent will be obtained from all participants. The trial has been approved by the Peking University Institutional Review Board (approval number: IRB00001052-18094). The results will be disseminated through academic conferences and publications in international peer-reviewed journals.Trail registration number ClinicalTrials.gov Registry (NCT03882645); Pre-results.

Tailoring the morphology and distribution of the Al2Ca second phase is important for improving mechanical properties of Al2Ca-containing Mg-Al-Ca based alloys. This work employed the industrial-scale multi-pass rotary-die equal channel angular pressing (RD-ECAP) on an as-cast Mg-3.7Al-1.8Ca-0.4Mn (wt %) alloy and investigated its microstructure evolution and mechanical properties under three different processing parameters. The obtained results showed that RD-ECAP was effective for refining the microstructure and breaking the network-shaped Al2Ca phase. With the increase of the ECAP number and decrease of the processing temperature, the average sizes of Al2Ca particles decreased obviously, and the dispersion of the Al2Ca phase became more uniform. In addition, more ECAP passes and lower processing temperature resulted in finer α-Mg grains. Tensile test results indicated that the 573 K-12p alloy with the finest and most dispersed Al2Ca particles exhibited superior mechanical properties with tensile yield strength of 304 MPa, ultimate tensile strength of 354 MPa and elongation of 10.3%. The improved comprehensive mechanical performance could be attributed to refined DRX grains, nano-sized Mg17Al12 precipitates and dispersed Al2Ca particles, where the refined and dispersed Al2Ca particles played a more dominant role in strengthening the alloys.

Metallic nanowires usually exhibit ultrahigh strength but low tensile ductility, owing to their limited strain hardening capability. Here, our larger scale molecular dynamics simulations demonstrated that we could rebuild the highly desirable strain hardening behavior at a large strain (0.21 to 0.31) in twinned Au nanowires by changing twin orientation, which strongly contrasts with the strain hardening at the incipient plastic deformation in low stacking-fault energy metals nanowires. Because of this strain hardening, an improved ductility is achieved. With the change of twin orientation, a competing effect between partial dislocation propagation and twin migration is observed in nanowires with slant twin boundaries. When twin migration gains the upper hand, the strain hardening occurs. Otherwise, the strain softening occurs. As the twin orientation increases from 0° to 90°, the dominating deformation mechanism shifts from slip-twin boundary interaction to dislocation slip, twin migration, and slip transmission in sequence. Our work could not only deepen our understanding of the mechanical behavior and deformation mechanism of twinned Au nanowires, but also provide new insights into enhancing the strength and ductility of nanowires by engineering the nanoscale twins.

In this work, it is presented for the first time that nitrogen and chlorine co-doped carbon nanodots (N,Cl-CDs) were synthesized by simply mixing glucose, concentrated hydrochloric acid (HCl), and 1,2-ethylenediamine (EDA). No external heat was employed; the neutralization reaction served as the heat source. The glucose served as the carbon source while EDA and HCl were the N and Cl dopants, respectively. The fluorescence of N,Cl-CDs was adequately quenched by hexavalent chromium Cr(VI) based on a combination of dynamic quenching and inner filter effect (IFE). Accordingly, an efficient N,Cl-CDs-based fluorescence probe was established for sensitive and selective detection of Cr(VI). The proposed fluorescence sensor provides a linear recognition range for Cr(VI) determination from 3 to 40 µM with a limit of detection (LOD) of 0.28 µM (14.6 µg/L). The proposed fluorescence method was successfully utilized to detect Cr(VI) in different water samples with satisfactory results. The spike recoveries vary from 97.01% to 103.89% with relative standard deviations (RSDs) of less than 0.82%. This work highlights the development of a simple, ultrafast, and energy-saving one-step synthetic route to fabricate N,Cl-CDs for highly selective and sensitive detection of Cr(VI) in real water samples. It is anticipated that the proposed fluorescence method could be further explored and widely used for Cr(VI) detection in the environmental industry.

Developing cost-effective magnesium alloys with high strength and good ductility is a long-standing challenge for lightweight metals. Here we present a multimodal grain structured AZ91 Mg alloy with both high strength and good ductility, prepared through a combined processing route of low-pass ECAP with short-time aging. This multimodal grain structure consisted of coarse grains and fine grains modified by heterogeneous precipitates, which resulted from incomplete dynamic recrystallization. This novel microstructure manifested in both superior high strength (tensile strength of 360 MPa) and good ductility (elongation of 21.2%). The high strength was mainly attributed to the synergistic effect of grain refinement, back-stress strengthening, and precipitation strengthening. The favorable ductility, meanwhile, was ascribed to the grain refinement and multimodal grain structure. We believe that our microstructure control strategy could be applicable to magnesium alloys which exhibit obvious precipitation strengthening potential.