Due to increased concerns about food safety, rapid, specific and highly sensitive monitoring of pathogen bacteria in food samples is of great importance to ensure public health. Although traditional ...detection methods are available, they are time consuming, labor intensive, unsuitable for on-site detection, and need highly trained personnel. To overcome these limitations, many efforts have been devoted to develop a new class of bioassays, aptamer-based assays, which use nucleic acid as bio-recognition elements. Aptamer-based assays and aptasensors, as emerging analytical methods, have opened new horizons for simple, specific and sensitive detection of microorganisms including pathogen bacteria. This review therefore will focus on new developed aptamer-based assays and aptasensors for pathogenic bacteria in food samples. We will also highlight advantages and drawbacks of various types of assays developed for pathogen bacteria detection.
•Detection of pathogenic bacteria in food samples is of great impotence to ensure public health.•Traditional detection methods are time consuming and labor intensive.•Development of highly sensitive analytical procedures is required.•Recently, aptamer-based assays have gained a considerable attention.•We have evaluated advantages and limitations of different strategies for the fabrication of aptamer-based assays.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UL, UM, UPCLJ, UPUK, ZRSKP
•High-throughput qPCR-based chip was developed to simultaneously quantify 27 HPBs.•The HPB-Chip showed high specificity at the species level and high sensitivity via low LoQ.•The HPB-Chip was ...successfully applied to wastewater systems in urban environment.
Waterborne pathogens are threatening public health globally, but profiling multiple human pathogenic bacteria (HPBs) in various polluted environments is still a challenge due to the absence of rapid, high-throughput and accurate quantification tools. This work developed a novel chip, termed the HPB-Chip, based on high-throughput quantitative polymerase chain reactions (HT-qPCR). The HPB-Chip with 33-nL reaction volume could simultaneously complete 10,752 amplification reactions, quantifying 27 HPBs in up to 192 samples with two technical replicates (including those for generating standard curves). Specific positive bands of target genes across different species and single peak melting curves demonstrated high specificity of the HPB-Chip. The mixed plasmid serial dilution test validated its high sensitivity with the limit of quantification (LoD) of averaged 82 copies per reaction for 25 target genes. PCR amplification efficiencies and R2 coefficients of standard curves of the HPB-Chip averaged 101 % and 0.996, respectively. Moreover, a strong positive correlation (Pearson’ r: 0.961–0.994, P < 0.001) of HPB concentrations (log10 copies/L) between HPB-Chip and conventional qPCR demonstrated high accuracy of the HPB-Chip. Subsequently, the HPB-Chip has been successfully applied to absolutely quantify 27 HPBs in municipal and hospital wastewater treatment plants (WWTPs) after PMA treatment. A total of 17 HPBs were detected in the 6 full-scale WWTPs, with an additional 19 in the hospital WWTP. Remarkably, Acinetobacter baumannii, Legionella pneumophila, and Arcobacter butzler were present in the final effluent of each municipal WWTP. Overall, the HPB-Chip is an efficient and accurate high-throughput quantification tool to comprehensively and rapidly quantify 27 HPBs in the environment.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Glaciers, which constitute the world's largest global freshwater reservoir, are also natural microbial repositories. The frequent pandemic in recent years underscored the potential biosafety risks ...associated with the release of microorganisms from the accelerated melting of glaciers due to global warming. However, the characteristics of pathogenic microorganisms in glaciers are not well understood. The glacier surface is the primary area where glacier melting occurs that is often the main subject of research on the dynamics of pathogenic microbial communities in efforts to assess glacier biosafety risks and devise preventive measures. In this study, high-throughput sequencing and quantitative polymerase chain reaction methods were employed in analyses of the composition and quantities of potential pathogenic bacteria on the surfaces of glaciers in the southeastern Tibetan Plateau. The study identified 441 potential pathogenic species ranging from 215 to 4.39 × 1011 copies/g, with notable seasonal and environmental variations being found in the composition and quantity of potential pathogens. The highest level of diversity was observed in April and snow, while the highest quantities were observed in October and cryoconite. Host analysis revealed that >70 % of the species were pathogens affecting animals, with the highest proportion of zoonotic pathogens being observed in April. Analysis of aerosols and glacial meltwater dispersion suggested that these microbes originated from West Asia, primarily affecting the central and southern regions of China. Null model analysis indicated that the assembly of potential pathogenic microbial communities on glacier surfaces was largely governed by deterministic processes. In conclusion, potential pathogenic bacteria on glacier surfaces mainly originated from the snow and exhibited significant temporal and spatial variation patterns. These findings can be used to enhance researchers' ability to predict potential biosafety risks associated with pathogenic bacteria in glaciers and to prevent their negative impact on populations and ecological systems.
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•Annually, approximately 1.7 × 1020 cells of potential pathogenic bacteria are released downstream.•Snow is the main carrier of potential pathogenic bacteria on glaciers.•Animals are the potential primary hosts for pathogenic bacteria on glaciers.•Pathogens found on glacier surfaces shows notable seasonal and environmental variations.•Deterministic processes dominated the potential pathogenic bacteria community assembly.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
We investigated the dynamics of feces-associated microorganisms in areas with wrack accumulation in the southeastern part of the Baltic Sea. Our study covered single-day (2021 ) and multi-day (2022) ...observations during the recreational season. We collected water, sand, and wrack samples and assessed the abundance of fecal indicator bacteria (FIB), as well metagenomic analysis was conducted to monitor changes in microbial composition. Based on metagenomic data we identified taxa associated with feces, sewage, and ruminant sources. Human-related fecal pollution based on genetic markers correlated with the presence of Lachnospiraceae, Prevotellaceae and Rickenellacea abundance. Higher abundance and diversity of feces-associated and ruminant-associated taxa and the presence of enteric pathogens were observed when wrack accumulated near the river outflow in 2021, suggesting a potential link with fecal pollution from the river. As a preventive measure, it is recommended to remove the wrack to reduce the risk of exposure to potential enteric pathogens if it is accumulated next to the river outflow.
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•Fecal pollution levels and sources were studied in wrack-affected environment.•Fecal pollution levels were estimated by cultivation.•Host-specific genetic markers and metagenomics were used to determine the source.•Humans, birds, ruminants and sewage were identified as sources of fecal pollution.•Feces-associated taxa and enteric pathogens were more abundant near river outflow.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Major histocompatibility complex II (MHCII) is a critical immune molecule that plays an essential role in combating external pathogens in fish. To investigate MHCII in the economically significant ...fish species, silver pomfret, we firstly identified three PaMHCIIs, including one PaMHCIIa and two PaMHCIIbs, all closely related to Trachinotus ovatus MHCII. Ig superfamily, C1-set and IGc1 domain were identified in PaMHCIIs, with MHCII alpha and MHCII beta domians found in PaMHCIIa and PaMHCIIbs, respectively. To further elucidate their immune function, we analyzed three transcriptomes from fish infected with a primary pathogenic bacterium, discovering that MHCII was highly enriched in Antigen processing and presentation (map04612). To explore the regulatory relationships of these differentially expressed genes (DEGs) in vitro, we established a Pampus argenteus kidney cell line (PaK) and construct a main pathogenic bacteria-Photobacterium damselae subsp. Damselae (PDD) infection PaK model according to the change of cell viability. In this model, the TUNEL signal did not exhibit significant changes at 6 h but increased gradually; compared to 0 h, tested genes were up-regulated at 6 h; All genes, except PaMHCIIs, GILT and CTSB, were up-regulated at 12 h. At 18 h, TCR was up-regulated while Ii and CTSL were significantly down-regulated. By 24 h, TCR, Ii and CTSL were down-regulated. These results suggest that the MHCII pathway is activated during the early stages of infection, but PDD may suppress it later through immune evasion mechanisms. This data enhances our understanding of the origin, evolution, and function of MHCII and provides guidance for disease control in silver pomfret aquaculture.
•We identified one MHCII a and two MHCII bs in silver pomfret.•We constructed Pampus argenteus kidney cell line (PaK).•MHCII were enriched in MHCII pathway in transcriptomes under exogenous stresses.•Acquired immunity regulated by MHCII was activated in early PDD infection in vitro.•PDD depressed the whole antigen processing and presentation through immune escape.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
A novel surface-enhanced Raman scattering (SERS)-based analytical technique was proposed to simultaneously detect two highly pathogenic bacteria, namely, Staphylococcus aureus (S. aureus) and ...Listeria monocytogenes (L. mono) by using a dual-recognition pattern with wheat germ agglutinin (WGA) and nucleic acid aptamers. WGA was modified onto Fe3O4@Au magnetic nanoparticles (MNPs) for the efficient capture of S. aureus and L. mono in complex samples (orange juice, extracts of lettuce, and human urine) within 15 min. The streptavidin (SA)/aptamers co-functionalized SERS tags were fabricated by covalent attaching two different Raman reporters and SA molecules onto 45 nm Au NPs and then conjugated with two biotin-aptamers that specifically bind to their target bacteria with high affinity and stability. The combined use of high-sensitive SERS tags, WGA-mediated magnetic enrichment, and SA-mediated aptamer conjugation remarkably improved the assay sensitivity. Under optimized conditions, the developed SERS biosensor can simultaneously detect the two target bacteria with high detection sensitivity (<6 cells/mL), favorable linear relation (10-107 cells/mL), and high accuracy (recovery rate <7.03%). Therefore, the proposed SERS platform is rapid, sensitive, easy to use, and thus show potential as a tool for the timely identification of pathogenic bacteria in real samples.
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•A rapid and ultrasensitive SERS platform for S. aureus and L. mono detection was reported.•WGA modified-Fe3O4@Au MNP was proposed for broad-spectrum capture of multiple bacteria.•The SA/aptamer co-functionalized SERS tags exhibited higher affinity and stability.•The LODs for S. aureus and L. mono were 3 and 5 cells/mL, respectively.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
Spider-derived peptides with insecticidal, antimicrobial and/or cytolytic activities, also known as spider venom antimicrobial peptides (AMPs), can be found in the venoms of RTA-clade spiders. They ...show translational potential as therapeutic leads. A set of 52 AMPs has been described in the Chinese wolf spider (Lycosa shansia), and many have been shown to exhibit antibacterial effects. Here we explored the potential to enhance their antimicrobial activity using bioengineering. We generated a panel of artificial derivatives of an A-family peptide and screened their activity against selected microbial pathogens, vertebrate cells and insects. In several cases, we increased the antimicrobial activity of the derivatives while retaining the low cytotoxicity of the parental molecule. Furthermore, we injected the peptides into adult Drosophila suzukii and found no evidence of insecticidal effects, confirming the low levels of toxicity. Our data therefore suggest that spider venom linear peptides naturally defend the venom gland against microbial colonization and can be modified into more potent antimicrobial agents that could help to battle infectious diseases in the future.
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•Bioengineering of three derivatives of a natural Lycosa shansia short linear venom peptide.•Enhanced charge and/or hydrophobicity in the engineered peptides.•Bioengineered modifications translate into increased antimicrobial activity.•Retained low toxicity to insects and vertebrate cells.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
The transmission of insect-borne plant pathogens, including viruses, bacteria, phytoplasmas, and fungi depends upon the abundance and behavior of their vectors. These pathogens should therefore be ...selected to influence their vectors to enhance their transmission, either indirectly, through the infected host plant, or directly, after acquisition of the pathogen by the vector. Accumulating evidence provides partial support for the occurrence of vector manipulation by plant pathogens, especially for plant viruses, for which a theoretical framework can explain patterns in the specific effects on vector behavior and performance depending on their modes of transmission. The variability in effects of pathogens on their vectors, however, suggests inconsistency in the occurrence of vector manipulation but also may reflect incomplete information about these systems. For example, manipulation can occur through combinations of specific effects, including direct and indirect effects on performance and behavior, and dynamics in those effects with disease progression or pathogen acquisition that together constitute syndromes that promote pathogen spread. Deciphering the prevalence and forms of vector manipulation by plant pathogens remains a compelling field of inquiry, but gaps and opportunities to advance it remain. A proposed research agenda includes examining vector manipulation syndromes comprehensively within pathosystems, expanding the taxonomic and genetic breadth of the systems studied, evaluating dynamic effects that occur during disease progression, incorporating the influence of biotic and abiotic environmental factors, evaluating the effectiveness of putative manipulation syndromes under field conditions, deciphering chemical and molecular mechanisms whereby pathogens can influence vectors, expanding the use of evolutionary and epidemiological models, and seeking opportunities to exploit these effects to improve management of insect-borne, economically important plant pathogens. We expect this field to remain vibrant and productive in its own right and as part of a wider inquiry concerning host and vector manipulation by plant and animal pathogens and parasites.
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•Biofilm formation by pathogenic bacteria is one of the major resistance mechanisms.•Chitosan is a natural product exploited for combating bacterial infections.•Several alternative ...strategies have been developed for the application of chitosan.•Strategies include chemical modifications or combination with another active agent.
Biofilm formed by several pathogenic bacteria results in the development of resistance against antimicrobial compounds. The polymeric materials present in the biofilm architecture hinder the entry of antimicrobial compounds through the surface of bacterial cells which are embedded as well as enclosed beneath the biofilm matrix. Recent and past studies explored the alternative approaches to inhibit the formation of biofilm by different agents isolated from plants, animals, and microbes. Among these agents, chitosan and its derivatives have got more attention due to their properties such as biodegradability, biocompatibility, non-allergenic and non-toxicity. Recent researches have focused on employing chitosan and its derivatives as effective agents to inhibit biofilm formation and attenuate virulence properties by various pathogenic bacteria. Such antibiofilm activity of chitosan and its derivatives can be further enhanced by conjugation with a wide range of bioactive compounds. The present review describes the antibiofilm properties of chitosan and its derivatives against the pathogenic bacteria. This review also summarizes the mechanisms of biofilm inhibition exhibited by these molecules. The knowledge of the antibiofilm activities of chitosan and its derivatives as well as their underlying mechanisms provides essential insights for widening their applications in the future.
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GEOZS, IJS, IMTLJ, KILJ, KISLJ, NLZOH, NUK, OILJ, PNG, SAZU, SBCE, SBJE, UILJ, UL, UM, UPCLJ, UPUK, ZAGLJ, ZRSKP
