Osr1-mediated mesothelial transition of liver mesenchymal cells exacerbates fibrotic liver damage.

In chronic liver diseases, hepatic stellate cells (HSCs) are induced to form the myofibroblasts responsible for scar formation, leading to liver fibrosis and cirrhosis. Here, single-cell RNA sequencing with in vivo lineage tracing in nonalcoholic steatohepatitis (NASH) model mice reveals a subpopulation of HSCs transitioning back to a state resembling their developmental precursors, mesothelial cells (MCs), after liver injury. These damage-associated intermediates between HSCs and MCs (DIHMs) can be traced with a dual recombinase system by labeling Krt19-expressing cells within prelabeled Pdgfrb+ HSCs, and DIHMs highly express inflammation- and fibrosis-associated genes. Cre and Dre-inducible depletion of DIHMs by administering diphtheria toxin reduces liver fibrosis and alleviates liver damage in NASH model mice. Importantly, knockdown of Osr1, a zinc finger transcription factor of the OSR gene family, can block DIHM induction in vitro. Conditional knockout Osr1 in Pdgfrb-expressing mesenchymal cells in NASH model mice can reduce liver fibrosis in vivo. Our study collectively uncovers an injury-induced developmental reversion process wherein HSCs undergo what we call a mesenchymal-to-mesothelial transition, which can be targeted to develop interventions to treat chronic liver diseases.

Multiphoton Ionization/Dissociation of Molecular Sulfur S2 in the UV Region.

The multiphoton ionization/dissociation dynamics of molecular sulfur (S2) in the ultraviolet range of 205-300 nm is studied using velocity map ion imaging (VMI). In this one-color experiment, molecular sulfur (S2) is generated in a pulsed discharge and then photodissociated by UV radiation. At the three-photon level, superexcited states are accessed via two different resonant states: the B3Σu- (v' = 8-11) valence states at the one-photon level and a Rydberg state at the two-photon level. Among the decay processes of these superexcited states, dissociation to electronically excited S atoms is dominant as compared to autoionization to ionic states S2+ (X2Πg) at wavelengths λ < 288 nm. The anisotropy parameter extracted from these images reflects the parallel character of these electronic transitions. In contrast, autoionization is found to be particularly efficient at S(1D) and S(1S) detection wavelengths around 288 nm. Information obtained from the kinetic energy distributions of S atoms has revealed the existence of vibrationally excited S2+ (X2Πg (v+ > 11)) that dissociates to ionic products following one-photon absorption. This work also reveals many interesting features of S2 photodynamics compared to those of electronically analogous O2.

Photoionization cross sections measurements of the excited states of lutetium and ytterbium in the near threshold region.

In this work, the threshold photoionization cross sections from the excited states of lutetium and ytterbium atoms were investigated by the laser pump-probe scheme under the condition of saturated resonant excitation. We obtained the resonance enhanced multiphoton ionization spectra of the lutetium and ytterbium atoms of the lanthanide metals in the range of 307.50-312.50 nm and 265.00-269.00 nm, respectively; the photoionization cross sections of the 5d6s(1D)6p(2D05/2) and 5d6s(3D)6p(2P01/2) states of lutetium and the 4f13(2F0)5d6s2(J = 1) states of ytterbium above threshold regions (0.4-1.6 eV) were measured, and measured values ranged from 2.3 ± 0.2 to 17.7 ± 1.5 Mb.

Optical nanosensors based on noble metal nanoclusters for detecting food contaminants: A review.

Food contaminants present a significant threat to public health. In response to escalating global concerns regarding food safety, there is a growing demand for straightforward, rapid, and sensitive detection technologies. Noble metal nanoclusters (NMNCs) have garnered considerable attention due to their superior attributes compared to other optical materials. These attributes include high catalytic activity, excellent biocompatibility, and outstanding photoluminescence properties. These features render NMNCs promising candidates for crafting nanosensors for food contaminant detection, offering the potential for the development of uncomplicated, swift, sensitive, user-friendly, and cost-effective detection approaches. This review investigates optical nanosensors based on NMNCs, including the synthesis methodologies of NMNCs, sensing strategies, and their applications in detecting food contaminants. Furthermore, it involves a comparative assessment of the applications of NMNCs in optical sensing and their performance. Ultimately, this paper imparts fresh perspectives on the forthcoming challenges. Hitherto, optical (particularly fluorescent) nanosensors founded on NMNCs have demonstrated exceptional sensing capabilities in the realm of food contaminant detection. To enhance sensing performance, future research should prioritize atomically precise NMNCs synthesis, augmentation of catalytic activity and optical properties, development of high-throughput and multimode sensing, integration of NMNCs with microfluidic devices, and the optimization of NMNCs storage, shelf life, and transportation conditions.

Detection of trace phosphorus in water by plasma amplification laser-induced breakdown spectroscopy.

For monitoring the extent of eutrophication in water, phosphorus (P) was detected by laser-induced breakdown spectroscopy (LIBS). A plasma amplification method was proposed and the filtered aerosol was guided to interact with the collinear laser in conjunction with a nebulizer, cyclonic spray chamber, and quartz tube. With this method, the length of the plasma was amplified from 5.27∼8.73 to 17.58 mm. Moreover, the limit of detection (LoD) values of P in water improved from 6.13∼17.75 to 3.60 ppm. Furthermore, the average relative error (REAV) values reduced from 10.23∼23.84 to 6.17%. The root mean square error of cross-validation (RMSECV) values decreased from 16.68∼64.29 to 3.24 ppm. This demonstrated that plasma amplification LIBS could improve the quantitative analysis performance of LIBS detection of trace phosphorus in water.

Elevated expression of CXCL3 in colon cancer promotes malignant behaviors of tumor cells in an ERK-dependent manner.

BACKGROUND: CXC chemokine ligand 3 (CXCL3) is a member of CXC-type chemokine family that is identified as a major regulator in immune and inflammation responses. Recently, numerous evidence indicated that CXCL3 is broadly expressed in various human tumor types, and it is also known to play a critical role in mediating tumor development and progression. However, the expression profile of CXCL3 and the exact molecular mechanism behind the role of CXCL3 in colon adenocarcinoma (COAD) has not been fully elucidated. METHODS: The expression and clinical significance of CXCL3 mRNA and protein in the tissues from COAD patients were estimated using bioinformatics and immunohistochemistry assays. The expression and roles of exogenous administration or overexpression of CXCL3 in HT-29 and SW480 COAD cells were determined using enzyme-linked immunosorbent assay(ELISA), Cell Counting Kit-8 (CCK-8) and Transwell assays. Mechanically, CXCL3-induced malignant behaviors were elucidated using western blotting assay and extracellular signal-regulated protein kinase 1/2 (ERk1/2) inhibitor PD98059. RESULTS: The cancer genome atlas (TCGA)-COAD data analysis revealed that CXCL3 mRNA is highly expressed and has high clinical diagnostic accuracy in COAD. Increased expression of CXCL3 mRNA was associated with patient's clinical stage, race, gender, age, histological subtype, nodal mestastasis and tumor protein 53 (TP53) mutation status. Similarly, immunohistochemistry assay also exhibited that CXCL3 protein in COAD tissues was significantly up-regulated. Gene expression associated assay implied that CXC chemokine ligand 1 (CXCL1) and CXC chemokine ligand 2 (CXCL2) were markedly correlated with CXCL3 in COAD. Protein-protein interaction (PPI) analysis revealed that cyclin B1 (CCNB1), mitotic arrest deficient 2 like 1 (MAD2L1), H2A family member Z (H2AFZ) and CXCL2 may be the important protein molecules involved in CXCL3-related tumor biology. Gene set enrichment analysis (GSEA) analysis revealed that CXCL3 was mainly enriched in the cell cycle, DNA replication, NOD-like receptors, NOTCH and transforming growth factor-ß (TGF-ß) Signal pathways. In vitro, exogenous administration or overexpression of CXCL3 resulted in increased malignant behaviors of HT-29 and SW480 cells, and down-regulation of CXCL3 expression inhibited the malignant behaviors of these tumor cells. In addition, overexpression of CXCL3 affected the expression of genes related to extracellular signal regulated kinase (ERK) pathway, including ERK1/2, p-ERK, B-cell lymphoma-2 (Bcl-2), Bcl-2-associated X protein (Bax) and Cyclin D1. Finally, CXCL3-induced malignant behaviors in HT-29 and SW480 cells were obviously attenuated following treatment with ERK inhibitor PD98059. CONCLUSION: CXCL3 is upregulated in COAD and plays a crucial role in the control of malignant behaviors of tumor cells, which indicated its involvement in the pathogenesis of COAD.

Sensory impairment and cognitive function among older adults in China: The mediating roles of anxiety and depressive symptoms.

OBJECTIVES: Through a cross-sectional study, we explored the association between sensory impairment and cognitive function in Chinese older adults, and tested the mediating roles of anxiety and depressive symptoms between this relationship. METHODS: Based on the 2018 Chinese Longitudinal Healthy Longevity Survey, a total of 10,895 older adults aged 65 and above were selected as samples for research. Anxiety, depressive symptoms and cognitive function were evaluated by the Generalized Anxiety Disorder, the Center for Epidemiologic Studies Depression (CES-D10) and the Chinese version of modified Mini-Mental State Examination scales, respectively. Sensory impairment was assessed from self-reported vision and hearing functions. Multiple linear regression and SPSS Macro PROCESS were used for statistical analysis. RESULTS: Compared with no sensory impairment, vision impairment (B = -1.012, 95%CI: -1.206, -0.818), hearing impairment (B = -2.683, 95%CI: -2.980, -2.386) and dual sensory impairment (B = -6.302, 95%CI: -6.585, -6.020) have a significant association with cognitive function in older adults, respectively. Anxiety and depressive symptoms not only acted as independent mediators, but also played sequential mediating effects on the relationship between sensory impairment and cognitive function. CONCLUSIONS: Greater attention should be paid to anxiety and depressive symptoms of older adults with sensory impairment, which might be beneficial to maintain cognitive function.

Far from the truth: Real-world treatment patterns among newly diagnosed metastatic prostate cancer in the era of treatment intensification.

OBJECTIVES: Real-world uptake of treatment intensification (TI) with novel hormonal agents (NHA) or chemotherapy as treatment of metastatic prostate cancer remains low outside of trial settings. We aim to report the prescription patterns and treatment outcomes of de novo metastatic hormone-sensitive prostate cancer (mHSPC) in a tertiary institution. METHODS: This is a retrospective cohort study using real-world data from a prospectively maintained prostate cancer registry. We selected patients newly diagnosed with mHSPC from January 2016 to December 2020. Clinicopathological parameters were recorded to determine their impact on prescription patterns. RESULTS: In total, 585 patients with metastatic prostate cancer were identified. Prescription of NHA increased from 10.5% (2016) to 50.4% (2020), but that of chemotherapy declined. Factors associated with TI were (1) baseline health status: Charlson Comorbidity Index 0-2, ECOG 0-1, age ≤ 65, (2) disease burden: PSA (>400, CHAARTED high volume disease, p = 0.004), development of systemic complications and (3) physician factor: primary physician being uro-oncologist and medical oncologist versus general urologist. Patients with TI had a longer mean time to castration-resistant prostate cancer (45.0 vs. 32.5 months, HR 0.567, 95% CI: 0.441-0.730, p < 0.001) and overall survival (55.3 vs. 46.8 months, HR 0.612, 95% CI, 0.447-0.837, p = 0.001). CONCLUSION: This study demonstrated the trend of treatment prescription of mHSPC and factors contributing to the use of TI. TI improved mean time to CRPC and OS.

Distributed Partial Discharge Locating and Detecting Scheme Based on Optical Fiber Rayleigh Backscattering Light Interference.

Optical fiber sensors are used for partial discharge detection in many applications due their advantage of strong anti-electromagnetic interference capability. Multi-point distributed partial discharge detection and location are important for electrical equipment. In this paper, a distributed partial discharge location and detection scheme based on optical fiber Rayleigh backscattering light interference is experimentally demonstrated. At the same time, the location and extraction algorithm is used to demodulate the partial discharge signal; furthermore, the high-pass filter is used to reduce the system low-frequency noise and environment noise. It is clear that the proposed system can detect a partial discharge signal generated by metal needle sensitivity, and the detectable frequency range is 0-2.5 kHz. We carried out 10 locating tests for two sensing units, the experimental results show that the maximum location error is 1.0 m, and the maximum standard deviation is 0.3795. At same time, the signal-to-noise ratio (SNR) of sensing unit 1 and sensing unit 2 are greatly improved after demodulation, which are 39.7 and 38.8, respectively. This provides a new method for a multipoint-distributed optical fiber sensor used for detecting and locating a long-distance electrical equipment partial discharge signal.

Nucleic acid amplification-based strategy to detect foodborne pathogens in milk: a review.

Milk contaminated with trace amounts of foodborne pathogens can considerably threaten food safety and public health. Therefore, rapid and accurate detection techniques for foodborne pathogens in milk are essential. Nucleic acid amplification (NAA)-based strategies are widely used to detect foodborne pathogens in milk. This review article covers the mechanisms of the NAA-based detection of foodborne pathogens in milk, including polymerase chain reaction (PCR), loop-mediated isothermal amplification (LAMP), recombinase polymerase amplification (RPA), rolling circle amplification (RCA), and enzyme-free amplification, among others. Key factors affecting detection efficiency and the advantages and disadvantages of the above techniques are analyzed. Potential on-site detection tools based on NAA are outlined. We found that NAA-based strategies were effective in detecting foodborne pathogens in milk. Among them, PCR was the most reliable. LAMP showed high specificity, whereas RPA and RCA were most suitable for on-site and in-situ detection, respectively, and enzyme-free amplification was more economical. However, factors such as sample separation, nucleic acid target conversion, and signal transduction affected efficiency of NAA-based strategies. The lack of simple and effective sample separation methods to reduce the effect of milk matrices on detection efficiency was noteworthy. Further research should focus on simplifying, integrating, and miniaturizing microfluidic on-site detection platforms.

Patient-reported outcomes of a phase II neoadjuvant apalutamide (ARN-509) and radical prostatectomy in treatment of intermediate- to high-risk prostate cancer (NEAR) trial.

OBJECTIVE: The NEAR trial is a single-arm phase II trial investigating the efficacy of neoadjuvant apalutamide and radical prostatectomy in the treatment of D'Amico intermediate- to high-risk prostate cancer. This publication focuses on health-related quality of life (HRQoL) during 12 weeks of neoadjuvant apalutamide treatment. METHODS: From 2017 to 2019, 30 suitable patients received neoadjuvant apalutamide 240 mg once daily for 12 weeks followed by radical prostatectomy (ClinicalTrials.gov Identifier: NCT03124433). Patient-reported quality of life outcomes was analyzed using European Organisation for Research and Treatment of Cancer Quality of Life Questionnaire Core Module (EORTC QLQ-C30), EORTC Quality of Life Questionnaire Prostate Module (QLQ-PR25), and Sexual Health Inventory for Men questionnaire (SHIM) at weeks 0,4,12, and 20 of the study. RESULTS: Thirty patients completed 12 weeks of apalutamide therapy and data analyzed for 29 with complete datasets. Neoadjuvant apalutamide therapy was associated with no clinically significant negative impact on patients' global health and QoL scores. Deteriorations in mean scores of functional and symptom scales of QLQ-C30 questionnaire were statistically significant (p = 0.011 and p = 0.008, respectively) but were not clinically meaningful. Patients were also affected by fatigue (p = 0.012), cognitive function (p = 0.038), reduced role functioning (p = 0.025), and lower SHIM scores (p < 0.001). Median daily step count reduced from 8228/day to 6001/day per day (p = 0.063), while BMI and body weight reduction were observed (statistically but not clinically significant). CONCLUSION: During 12 weeks of neoadjuvant apalutamide in organ-confined prostate cancer, the overall patient-reported HRQoL outcomes were maintained, but fatigue and sexual dysfunction were observed in those patients.

Invited review: Stress resistance of Cronobacter spp. affecting control of its growth during food production.

Members of the Cronobacter genus include food-borne pathogens that can cause infections in infants, with a mortality rate as high as 40 to 80%. The high fatality rate of Cronobacter and its isolation from numerous types of food, especially from powdered infant formula, demonstrate the serious nature of this organism. The source tracking of Cronobacter spp. and the analysis of high-frequency species from different sources are helpful for a more targeted control. Furthermore, the persistence during food processing and storage may be attributed to strong resistance of Cronobacter spp. to environment stresses such as heat, pH, and desiccation. There are many factors that support the survival of Cronobacter spp. in harsh environments, such as some genes, regulatory systems, and biofilms. Advanced detection technology is helpful for the strict monitoring of Cronobacter spp. In addition to the traditional heat treatment, many new control techniques have been developed, and the ability to control Cronobacter spp. has been demonstrated. The control of this bacteria is required not only during manufacture, but also through the selection of packaging methods to reduce postprocessing contamination. At the same time, the effect of inactivation methods on product quality and safety must be considered. This review considers the advances in our understanding of environmental stress response in Cronobacter spp. with special emphasis on its implications in food processing.

Assessment of the production of Bacillus cereus protease and its effect on the quality of ultra-high temperature-sterilized whole milk.

Bacillus cereus is one of the most important spoilage microorganisms in milk. The heat-resistant protease produced is the main factor that causes rotten, bitter off-flavors and age gelation during the shelf-life of milk. In this study, 55 strains of B. cereus were evaluated, of which 25 strains with protease production ability were used to investigate proteolytic activity and protease heat resistance. The results showed that B. cereus C58 had strong protease activity, and its protease also had the highest thermal stability after heat treatment of 70°C (30 min) and 100°C (10 min). The protease was identified as protease HhoA, with a molecular mass of 43.907 kDa. The protease activity of B. cereus C58 in UHT-sterilized whole milk (UHT milk) showed an increase with the growth of bacteria, especially during the logarithmic growth phase. In addition, the UHT milk incubated with protease from B. cereus C58 at 28°C (24 h) and 10°C (6 d) were used to evaluate the effects of protease on the quality of UHT milk, including protein hydrolysis and physical stability. The results showed that the hydrolysis of casein was κ-CN, ß-CN, and αS-CN successively, whereas whey protein was not hydrolyzed. The degree of protein hydrolysis, viscosity, and particle size of the UHT milk increased. The changes in protein and fat contents indicated that fat globules floated at 28°C and settled at 10°C, respectively. Meanwhile, confocal laser scanning microscopy images revealed that the protease caused the stability of UHT milk to decrease, thus forming age gelation.

A novel smartphone-based colorimetric aptasensor for on-site detection of Escherichia coli O157:H7 in milk.

Effective testing tools for Escherichia coli O157:H7 can prevent outbreaks of foodborne illness. In this paper, a smartphone-based colorimetric aptasensor was developed using functionalized gold nanoparticles (GNP) and multi-walled carbon nanotubes (MWCNT) for monitoring E. coli O157:H7 in milk. The maximum absorption peak of GNP bonded with aptamer (Apt) generated evident transformation from 518 to 524 nm. The excess GNP-Apt was removed by functionalized MWCNT magnetized with carbonyl iron powder (CIP) and hybridized with a DNA probe, whereas the GNP-Apt immobilized on E. coli O157:H7 remained in the system. In the presence of a high-salt solution, the GNP-Apt that captured E. coli O157:H7 remained red, but the free GNP-Apt aggregated and appeared blue. The chromogenic results were analyzed by a smartphone-based colorimetric device that was fabricated using acrylic plates, a light-emitting diode, and a mobile power pack. To our knowledge, this was the first attempt to use a smartphone-based colorimetric aptasensor employing the capture of GNP-Apt coupled with separation of MWCNT@CIP probe to detect E. coli O157:H7. The aptasensor exhibited good reproducibility and no cross-reaction for other bacteria. A concentration of 8.43 × 103 cfu/mL of E. coli O157:H7 could be tested in pure culture, and 5.24 × 102 cfu/mL of E. coli O157:H7 could be detected in artificially contaminated milk after 1 h of incubation. Therefore, the smartphone-based colorimetric aptasensor was an efficient tool for the detection of E. coli O157:H7 in milk.

An aptamer-exonuclease III (Exo III)-assisted amplification-based lateral flow assay for sensitive detection of Escherichia coli O157:H7 in milk.

Escherichia coli O157:H7 (E. coli O157:H7), one of the most widespread foodborne pathogens, can cause a series of diseases and even lead to death. In this study, a highly sensitive method was developed by combining aptamer-exonuclease III (Exo III)-assisted amplification with lateral flow assay (LFA) based on gold nanoparticles (AuNP). The compound of single-stranded (ss) DNA-anti-E. coli O157:H7 aptamer (ssDNA-aptamer) was formed by hybridization between designed target ssDNA and aptamer. When E. coli O157:H7 was present, target bacteria were bound with the aptamer, and the free target ssDNA was hybridized with the probes of the designed hairpin (HP) structure. Exo III digests the 3' double-stranded blunt end of the complex and releases the enzyme product. Because the remaining sequence of the HP of the designed enzyme product was the same as the target ssDNA sequence, the target ssDNA could be amplified. Finally, the enhanced target ssDNA was combined with AuNP-LFA to achieve visual detection of E. coli O157:H7. The quantitative ability of this platform for E. coli O157:H7 was 7.6 × 101 cfu/mL in pure culture, and the detection limit in milk was 8.35 × 102 cfu/mL. This LFA was highly specific to E. coli O157:H7, and the time for detection of E. coli O157:H7 in milk was 4 h. Hence, this system has important application prospects in the detection of pathogenic bacteria in dairy products.

Screening of specific nucleic acid targets for Cronobacter sakazakii and visual detection by loop-mediated isothermal amplification and lateral flow dipstick method in powdered infant formula.

Due to the lack of specific genes for rapid detection methods of Cronobacter sakazakii in food samples, whole genome sequence analysis was performed in this investigation using the basic local alignment search tool. Forty-two DNA fragments unique to C. sakazakii were mined, then primers were designed and screened by PCR and loop-mediated isothermal amplification (LAMP). Two primer sets, CS1 and CS31, were found as specific and stable primers, with their corresponding nucleic acid targets the CSK29544_00235 gene and CSK29544_03484 gene, respectively. Furthermore, compared with 3 genes reported previously, these 2 genes were verified as more specific to C. sakazakii among Cronobacter species, by sequence similarity alignment using Cronobacter MLST databases (http://pubmlst.org/cronobacter). The specificity of the LAMP reaction approached 100% by using 48 bacterial strains, which included 22 C. sakazakii strains. Subsequently, LAMP was combined with visual lateral flow dipstick (LFD) based on the above 2 nucleic acid targets, and was demonstrated as a rapid, efficient method with high specificity. Finally, the detection sensitivity of this assay system for pure cultures and artificially contaminated milk was measured as 4.5 × 100 cfu/mL and 5.7 × 101 cfu/g, respectively. Total time to detection for this assay was within 2 h. Thus, the establishment of this LAMP-LFD method shows great significance and potential for rapid detection of C. sakazakii in powdered infant formula.

Physicochemical and transcriptomic responses of Lactobacillus brevis JLD715 to sodium selenite.

BACKGROUND: Elemental selenium, as a new type of selenium supplement, can be prepared by microorganisms reducing inorganic selenium. In this study, Lactobacillus brevis JLD715 was incubated in broth containing different concentrations of sodium selenite (Na2 SeO3 ). RESULTS: The results showed that the bacterial biomass of L. brevis JLD715 decreased due to the inhibition of Na2 SeO3 . The cell membrane of L. brevis JLD715 treated with Na2 SeO3 was damaged, as evidenced by the reduction of intracellular ATP concentration, depolarization of cell membrane, reduction of intracellular pH and impairment of membrane integrity. In addition, we investigated the metabolism mechanism of Na2 SeO3 by L. brevis JLD715 based on transcriptome sequencing. A total of 461 genes were significantly differentially expressed under Na2 SeO3 treatment, of which 231 genes were up-regulated and 230 genes were down-regulated. These genes were involved in pathways such as pyruvate metabolism, fatty acid biosynthesis, selenocompound metabolism and nucleotide-binding oligomerization domain-like (NOD-like) receptor signaling. Meanwhile, the genes related to sulfhydryl oxidoreductase, electron carrier proteins and transmembrane transport proteins synthesis were significantly up-regulated. CONCLUSION: To sum up, the findings of this research will contribute to providing support for the application of L. brevis JLD715 in selenium-enriched functional foods. © 2021 Society of Chemical Industry.

Self-absorption reduction in laser-induced breakdown spectroscopy using laser-stimulated absorption: publisher's note.

This publisher's note contains corrections to Opt. Lett.40, 5224 (2015).OPLEDP0146-959210.1364/OL.40.005224.

Multiplex loop-mediated isothermal amplification-based lateral flow dipstick for simultaneous detection of 3 food-borne pathogens in powdered infant formula.

In this study, we established a rapid, simple, and sensitive method for visual and point-of-care detection of Salmonella spp., Cronobacter spp., and Staphylococcus aureus in powdered infant formula (PIF) based on multiplex loop-mediated isothermal amplification (mLAMP) combined with lateral flow dipstick (LFD). Three different species-specific target genes, siiA of Salmonella spp., internal transcribed space (ITS) of Cronobacter spp., and nuc of Staph. aureus, were applied in the mLAMP with biotin-, digoxin-, and Texas Red-modified forward inner primers and fluorescein isothiocyanate (FITC)-modified backward inner primers. After mLAMP, a large number of modified amplicons were detected with LFD; one end of the amplicon was conjugated to the anti-FITC antibody on gold nanoparticles and the other end to streptavidin (anti-digoxin or anti-Texas Red antibody) on test lines. Visual inspection of the device relies on the presence of a red band formed by accumulation of sandwich composites. The detection limits of this mLAMP-LFD assay for Salmonella spp., Cronobacter spp., and Staph. aureus in PIF without enrichment were 4.2, 2.6, and 3.4 cfu/g, respectively. The whole method can be completed in less than 1 h. Thus, mLAMP-LFD is a rapid and efficient method for simultaneously detecting Salmonella spp., Cronobacter spp., and Staph. aureus in PIF.

Electricity-free amplification and visual detection of Cronobacter species in powdered infant formula.

Due to the lack of electricity and thermostatic instruments in certain settings for convenient detection of Cronobacter species in powdered infant formula (PIF), a novel investigation was conducted to establish an electricity-free visual detection system for rapid detection of Cronobacter species in PIF. This system included a portable electricity-free heater that could use the exothermic reaction of calcium oxide and water and 3 kinds of phase change materials to supply 3 constant temperatures for immunomagnetic separation, DNA extraction, and loop-mediated isothermal amplification assay. Meanwhile, the amplified reaction combined with hydroxynaphthol blue could achieve rapid visual detection. Primers designed based on the 16S-23S ribosomal RNA internal transcribed spacer were used in loop-mediated isothermal amplification to specifically monitor Cronobacter species, and the detection limit can reach 4.2 × 102 cfu/g in PIF by an electricity-free heater in 2 h 30 min. Moreover, 2 h of pre-enrichment was necessary when the level of the PIF samples with Cronobacter spp. was 100 cfu/g. The stability of the system was evaluated in ambient temperature at 4°C, 25°C, and 37°C. The results suggested that the electricity-free heater can maintain 3 constant temperatures to support different processes. Therefore, this amplification and visual system is applicable for use in many fields for rapid and specific detection of Cronobacter species in PIF.