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Salmonella is a rod-shaped, Gram-negative zoonotic pathogen that poses a serious global socioeconomic and public health threat. Rapid and accurate detection of Salmonella spp. is critical for effective control of its infection. In this study, an accurate, sensitive and specific graphene oxide-assisted accelerated strand exchange amplification (GO-ASEA) method for rapid detection of Salmonella spp. was developed and validated. The detection limit of the GO-ASEA method was 8.6 × 10

An accurate, rapid and highly sensitive graphene oxide-based accelerated strand exchange amplification method was developed for quantitative detection of African swine fever virus (ASFV).

Exosome is considered an important biomarker of liquid biopsy in early cancer screening, which can reflect the physiological and pathological status of cancer cells. Herein, we construct a novel electrochemical biosensor based on hierarchical Au nanoarray-modified 2D Ti

The novel coronavirus disease 2019 caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been surging rapidly around the world, which has exposed humanity to unprecedented economic, social and health impacts. To achieve efficient and accurate detection of SARS-CoV-2 on site, we developed and verified a rapid and sensitive fluorescence lateral flow immunoassay based on the innovative enhanced strand exchange amplification (ESEA-LFIA) in this study. With good amplification efficiency for short-sequence targets, ESEA is an ideal choice for the point-of-care testing of SARS-CoV-2 with a high mutation rate. ESEA reaction can be completed in one step and verified by restriction enzyme digestion. The design consisting of three working primers greatly improved the amplification efficiency. Amplification of the target sequences of the RdRP and N genes can be accomplished under the same reaction conditions, and does not require expensive instruments. The sensitivity of the ESEA-LFIA assay targeting the RdRP and N genes was 90 copies per μL and 70 copies per μL, respectively. Specificity tests showed that the novel assay can specifically detect SARS-CoV-2, and had no cross-reactivity with 9 closely-related human pathogenic coronaviruses and other common respiratory pathogens with similar clinical manifestations. The cutoff values of the RdRP and N gene assays are 11 and 12, respectively, and the assays can be completed within 1 h. The novel strategy proposed in this study is a sensitive and specific method for the rapid detection of SARS-CoV-2, and is suitable as an effective potential bioanalytical tool to respond to future regional or global outbreaks of emerging infectious pathogens with high mutation rates.

Salmonella spp. are zoonotic pathogens of substantial public health concern. To enable detection in the field or under instrument-free conditions, we developed a rapid and robust lateral flow fluorescent immunoassay based on strand exchange amplification (SEA-LFIA) for the quantitative detection of Salmonella spp. As far as we know, this work is the first report regarding the use of Bst DNA polymerase-assisted SEA for fluorescence sensing to detect Salmonella spp. The SEA method was further confirmed by enzymatic digestion and Sanger dideoxy sequencing. The specificity of SEA-LFIA assay was verified by 89 Salmonella strains (18 Salmonella reference strains and 71 clinical isolates) and 15 non-Salmonella reference strains (different genera). The sensitivity of SEA-LFIA assay was 6 × 100 CFU mL-1 of Salmonella pure culture or 3 × 104 CFU 25 g-1 of artificially spiked raw chicken meat. Using this assay, it was found that 37 (16%) of the 236 samples collected were positive, which was consistent with the results of conventional PCR. The cutoff value is 15 and SEA-LFIA assay only takes ∼30 min without high equipment and reagent cost. In addition, the proposed strategy can be easily extended by redesigning the corresponding amplification primers to detect target analytes. In conclusion, the optimized SEA-LFIA assay is an efficient and specific method for the detection of Salmonella spp., and can potentially serve as a new on-site diagnostic tool in life sciences.

Salmonella enterica serovar Indiana (S. Indiana) is a newly emerging pathogen with high levels of drug resistance. It has become one of the most common Salmonella serovars in China with a worldwide distribution, posing significant public health concerns. Detection of S. Indiana by traditional bacteriological methods is time-consuming and laborious, which prevents timely surveillance and effective control of the pathogen. In this study, comparative genomics was used to identify an A7P63_13850 gene that is uniquely present in S. Indiana, but not in other Salmonella serovars or any non-Salmonella bacteria. Then, a polymerase chain reaction (PCR) assay targeting this serovar-specific gene was established for specific detection of S. Indiana. The detection limit of this method is 10 pg per reaction for bacterial genomic DNA, being equivalent to 100 colony-forming units (CFU) per reaction. The established PCR amplifies all S. Indiana strains (n = 56), but none of other Salmonella serovars (n = 146) and non-Salmonella species (n = 14). The assay established in this study was also used to detect clinical samples from poultry, showed a positivity of 14.7% (23/156) for S. Indiana, which were verified by bacteriological methods. The highly sensitive and serovar-specific PCR for S. Indiana established in this study is suitable and convenient for detection of S. Indiana which aids in surveillance and control of the pathogen.

Interventional embolization is a popular minimally invasive vascular therapeutic technique and has been widely applied for hepatocellular carcinoma (HCC) therapy. However, harmful effects caused by transcatheter arterial chemoembolization (TACE) and radioembolization, such as the toxicity of chemotherapy or excessive radiation damage, are serious disadvantages and significantly reduce the therapeutic efficacy. Here, a synergistic therapeutic strategy combined transcatheter arterial embolization and magnetic ablation (TAEMA) by using poly(lactic-co-glycolic acid) (PLGA)-magnetic microspheres (MMs) has been successfully applied to orthotopic VX2 liver tumors of rabbits. These MMs fabricated by novel rotating membrane emulsification system with well-controlled sizes (100-1000 μm) exhibited extremely low hemolysis ratio and excellent biocompatibility with HepG2 cells and L02 cells. Moreover, experimental results demonstrated that, while exposed to alternating magnetic field (AMF) after TAE, the tumor edge could be heated up by more than 15 °C both in vivo and in vitro, whereas only a negligible increase of temperature was observed in the normal hepatic parenchyma (NHP) nearby. Sufficient temperature increase induces apoptosis of tumor cells. This can further inhibit the tumor angiogenesis and results in necrosis compared to the rabbits only treated with TAE. In stark contrast, tumors rapidly grow and subtotal metastasis occurs in the lungs or kidneys, causing severe complications for rabbits only irradiated under AMF. Importantly, the results from the biochemical examination and the gene expression of relative HCC markers further confirmed that the treatment protocol using PLGA-MMs could achieve good biosafety and excellent therapeutic efficacy, which are promising for liver cancer therapy.

BACKGROUND: Bacillary dysentery caused by Shigella genus is a major cause of morbidity and mortality worldwide. In China, the popular strain was mainly Shigella flexneri (S. flexneri). Therefore, fluorescent microspheres (FMs)-based immunochromatographic test strip (ICTS), as a novel, reliable, sensitive and uncomplicated method, was evaluated to detect S. flexneri. METHODS: Sixty-three clinical samples of S. flexneri were collected in this paper. Polymerase chain reaction (PCR) combined with FMs-ICTS based on magnetic purification assay was developed for the quantitative detection of Shigella. And the genus-specific gene of ipaH and drug resistant gene of CTX-M-9 from Shigella were selected to investigate the potential of this new method. The sensitivity and specificity of this method were demonstrated by classical microbiological methods (API Coryne System), PCR assay based on agarose gel electrophoresis (PCR-GE) and the real-time fluorescent quantitative PCR (RTFQ-PCR) method. RESULTS: Under optimized conditions, the lower detection limits of PCR-ICTS, PCR-GE and RTFQ-PCR were 2.5×10(−7), 2.5×10(−5) and the 3.2×10(−7) ng/µL, respectively. Experiments demonstrated the PCR-ICTS has a diagnostic agreement of 100% with conventional PCR and RTFQ-PCR on detection of clinical samples and could correctly recognize Shigella and non-Shigella from different microbial samples. After the purification of PCR products with Silicon coated magnetic nanoparticles (Si-MNPs), the false positive results were removed because of the strong screening ability of the purification process. Our results showed that FM-based ICTS was promising for measurable and sensitive detection of S. flexneri within 3 h. CONCLUSIONS: The results from immunochromatographic test were agreement with those from API Coryne system and RTFQ-PCR. Hence, this developed method might be useful for screening and monitoring clinical sample of S. flexneri, due to its speed, non-poisonous, simplicity and low-cost and helpful for promoting the prevention and control of communicable diseases caused by enteric pathogens such as S. flexneri.

Polymerase chain reaction (PCR) plays an increasingly important role in microbial detection. However, the existing methods are difficult to be widely applied due to factors such as instruments, reagents, and experimental conditions. In this study, we developed a robust and reliable fluorescent lateral flow immunoassay combined with polymerase chain reaction (PCR-LFIA) based on magnetic beads purification for rapid detection of Salmonella app. The PCR-LFIA assay can avoid false positives caused by primer dimers. The sensitivity of PCR-LFIA method was 6×100 CFU/mL of Salmonella pure culture or 6×102 CFU/mL of artificially spiked chicken faeces. The specificity of PCR-LFIA assay was verified by eighteen Salmonella and non-Salmonella reference strains. Six of the eighty-five (7.1%) samples collected were positive by PCR-LFIA assay and the results were further confirmed by biochemical characteristics. This assay allows quantitative detection of Salmonella with a cutoff value of 175 and can be completed in 80 minutes. In conclusion, the optimized PCR-LFIA method can potentially serve as an effective diagnostic tool for timely response to disease outbreaks.

In this study, a simple approach was described for the fabrication of CaSO4/Fe0 composite used as a novel adsorbent for the reductive removal of Cu2+ from aqueous solutions. The magnetic CaSO4/Fe0 composite was prepared by a solid state reaction at 550 °C in the H2 atmosphere using CaSO4·2H2O/α-FeOOH as a precursor. The structure and morphology of the as-synthesized magnetic composite were characterized by X-ray diffraction, field emission scanning electron microscopy and a superconducting quantum interference device, respectively. Results showed that the CaSO4/Fe0 composite with a rod-like shape could be easily acquired from the CaSO4·2H2O/α-FeOOH precursor with the ratio of 1:0.5 at 550 °C in the H2 atmosphere for 1 h. The CaSO4/Fe0 composite exhibited enhanced performance relevant to the reductive removal of Cu2+. The removal amount of Cu2+ increased linearly with increasing of concentration of Cu2+ in wastewater. Possible removal mechanisms were proposed as follows: (1) the formation of Cu2O by fast reduction of Cu2+ with Fe0 nanoparticles on interface of CaSO4/Fe0 composite, (2) proper adsorption of Cu2+ on the surface of CaSO4/Fe0 composite, (3) the hydrous iron oxide (HIO) such as Fe (OH)3 and FeOOH in situ generated on the rest of CaSO4/Fe0 composite could further adsorb Cu2+ from wastewater.

Chemotherapy has been major and standard strategy that is widely used in the treatment of acute myeloid leukemia (AML). However, for the lack of specificity of free drugs, patients are suffering from the non-specific toxicity and high recurrence rate. The C-X-C chemokine receptor type 4 (CXCR4) and cluster determinant 44 (CD44) are becoming highly appealing target candidates as the markers for AML relapse. Here, we designed and fabricated pH-responsive CXCR4 and CD44 dual-targeted nanosystems, based on Prussian blue nanoparticles (PBNPs) for AML therapy. The polyethylene glycol-grafted polyethylenimine with benzoic-imine bond modified PBNPs were synthesized and then functionalized with CXCR4 targeting peptide E5 and CD44 targeting moiety hyaluronic acid (HA). Daunorubicin (DNR) was selected as a model anti-AML drug. The dual-targeted PBNPs achieved not only effective endosomal escape but also prolonged blood retention time in physiological condition. Moreover, the cleavage of PEG chain in the endosome enabled to rapidly release DNR. The dual-targeted PBNPs exhibited increased internalization, improved anti-HL60 cells effect, and reduced HL60 cells migration and adhesion induced by bone marrow stroma cells compared with mono-targeted PBNPs. The in vivo results showed that DNR-loaded dual-targeted PBNPs displayed more powerful capability to block the proliferation of leukemia blasts in bone marrow, peripheral blood and spleen in AML mice xenograft model. More importantly, the dual-targeted PBNPs also inhibited leukemia blasts metastatic to liver and spleen, reversed splenomegaly, and extended the overall survival. Therefore, the dual-targeted PBNPs represent a promising strategy for advancing therapeutics for AML therapy.

Background Canine parvovirus 2 (CPV-2) is one of the most common etiological agents that cause severe gastroenteritis in puppies. Early accurate diagnosis is important for infected dogs. In recent years, magnetic separation has become an efficient and useful tool for bioassays. In this study, polymerase chain reaction (PCR) combined with fluorescent lateral flow immunoassay (LFIA) based on magnetic purification assay was developed for the quantitative detection of CPV-2. Results The optimum working reaction volume and reaction time for LFIA was 100 μL and 2 min, respectively. The PCR-LFIA assay only detected CPV-2, and did not show cross-detection of non-CPV strains. Experiments showed analytical sensitivity of 3 × 101 copies/μL and demonstrated the PCR-LFIA has a diagnostic agreement of 100% with conventional PCR on detection of clinical samples (22.6% positive, 14/62). Cutoff value is 146. The results were further verified by sequencing and BLAST software. The entire process from PCR step only takes ~ 80 min. Conclusions This approach provides an attractive platform for rapid and quantitative detection of CPV-2, indicating great promise as a convenient molecular detection tool to facilitate disease outbreak investigations and response timely.

Nota de investigación- Distribución de genes de virulencia de los aislamientos de Salmonella pullorum recuperados de los pollos en China (1953–2015). Salmonella enterica subespecie enterica serovar Gallinarum biovar Pullorum (Salmonella Pullorum) tiene una estricta especificidad de hospedador en la avicultura y la enfermedad por S. Pullorum es una seria amenaza para la industria avícola. Los genes de virulencia desempeñan un papel central en la patogenicidad de Salmonella, pero hay muy pocos reportes disponibles sobre la distribución de los genes de virulencia en Salmonella Pullorum. En este estudio, se investigaron 304 aislamientos de Salmonella Pullorum recuperados de pollos en China entre los años 1953 y 2015 para detectar la presencia de 25 genes de virulencia de Salmonella (invA, orgA, prgH, sitC, spaN, sifA, spiA, ttrC, mgtB, misL, siiE, spi4D, pipA, sipB, sopB, sefA, cdtB, pagC, shdA, msgA, lpfC, tolC, iroN, pefA y spvB), incluidos los genes de las islas de patogenicidad, los genes de fimbrias y los genes de plásmidos de virulencia. Los métodos de PCR mostraron que 15 de los 25 genes de virulencia estaban presentes en todos los aislamientos analizados, mientras que el gene cdtB no estaba presente en ninguno de los aislados. Las tasas de prevalencia de los genes restantes oscilaron entre 97.7% y 99.7%. Las tasas de variación de estos genes de virulencia fueron bajas y no se identificaron diferencias significativas en la distribución de los genes de virulencia a lo largo del tiempo. Sobre la base de la distribución de estos genes de virulencia, los 304 aislamientos de Salmonella Pullorum se dividieron en 10 genotipos de virulencia. El genotipo principal, que comprendía al 93.4% de todos los aislamientos, incluía aislamientos que llevaban 24 de los genes de virulencia evaluados. Los resultados de este estudio ayudarán en la caracterización de Salmonella Pullorum y al estudio de la correlación entre los genotipos de virulencia y la patogenicidad.

Interventional embolization is a popular minimally invasive vascular therapeutic technique and has been widely applied for hepatocellular carcinoma (HCC) therapy. However, harmful effects caused by transcatheter arterial chemoembolization (TACE) and radioembolization, such as the toxicity of chemotherapy or excessive radiation damage, are serious disadvantages and significantly reduce the therapeutic efficacy. Here, a synergistic therapeutic strategy combined transcatheter arterial embolization and magnetic ablation (TAEMA) by using poly(lactic-co-glycolic acid) (PLGA)-magnetic microspheres (MMs) has been successfully applied to orthotopic VX

Background: Bacillary dysentery caused by Shigella genus is a major cause of morbidity and mortality worldwide. In China, the popular strain was mainly Shigella flexneri ( S. flexneri ). Therefore, fluorescent microspheres (FMs)-based immunochromatographic test strip (ICTS), as a novel, reliable, sensitive and uncomplicated method, was evaluated to detect S. flexneri . Methods: Sixty-three clinical samples of S. flexneri were collected in this paper. Polymerase chain reaction (PCR) combined with FMs-ICTS based on magnetic purification assay was developed for the quantitative detection of Shigella . And the genus-specific gene of ipaH and drug resistant gene of CTX-M-9 from Shigella were selected to investigate the potential of this new method. The sensitivity and specificity of this method were demonstrated by classical microbiological methods (API Coryne System), PCR assay based on agarose gel electrophoresis (PCR-GE) and the real-time fluorescent quantitative PCR (RTFQ-PCR) method. Results: Under optimized conditions, the lower detection limits of PCR-ICTS, PCR-GE and RTFQ-PCR were 2.5×10 −7 , 2.5×10 −5 and the 3.2×10 −7 ng/µL, respectively. Experiments demonstrated the PCR-ICTS has a diagnostic agreement of 100% with conventional PCR and RTFQ-PCR on detection of clinical samples and could correctly recognize Shigella and non- Shigella from different microbial samples. After the purification of PCR products with Silicon coated magnetic nanoparticles (Si-MNPs), the false positive results were removed because of the strong screening ability of the purification process. Our results showed that FM-based ICTS was promising for measurable and sensitive detection of S. flexneri within 3 h. Conclusions: The results from immunochromatographic test were agreement with those from API Coryne system and RTFQ-PCR. Hence, this developed method might be useful for screening and monitoring clinical sample of S. flexneri , due to its speed, non-poisonous, simplicity and low-cost and helpful for promoting the prevention and control of communicable diseases caused by enteric pathogens such as S. flexneri .

Salmonella enterica subspecies enterica serovar Gallinarum biovar Pullorum (Salmonella Pullorum) has strict host specificity for poultry, and pullorum disease seriously threatens the poultry industry. Virulence genes play a central role in Salmonella pathogenicity, but very few reports are available on the distribution of virulence genes in Salmonella Pullorum. In this study, we investigated 304 Salmonella Pullorum isolates recovered from chickens in China between 1953 and 2015 for the presence of 25 Salmonella virulence genes (invA, orgA, prgH, sitC, spaN, sifA, spiA, ttrC, mgtB, misL, siiE, spi4D, pipA, sipB, sopB, sefA, cdtB, pagC, shdA, msgA, lpfC, tolC, iroN, pefA, and spvB), including pathogenicity island genes, fimbriae genes, and virulence plasmid genes. PCR showed that 15 of the 25 virulence genes were present in all isolates tested, whereas cdtB was not present in any isolate. The presence rates of the remaining genes ranged from 97.7% to 99.7%. The variation rates of these virulence genes was low, and no significant differences were identified in the distribution of virulence genes over time. On the basis of the distribution of these virulence genes, the 304 Salmonella Pullorum isolates were divided into 10 virulence genotypes. The major genotype, which comprised 93.4% of all isolates, included isolates that carried 24 of the virulence genes assessed. The results of this study will help in the characterization of Salmonella Pullorum and in the study of the correlation between virulence genotypes and pathogenicity.

Torque teno virus is a nonenveloped single-stranded DNA virus infecting humans and nonprimate species. We report the complete genome sequence of a pigeon torque teno virus isolated from pigeons in Jiangsu Province, China, in 2012. This genome sequence will be useful for viral diagnostics and disease control.