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The interdiction of restricted and hazardous biological agents presents challenges for any detection method due to the inherent complexity of sample type and accessibility. Detection capabilities for this category of agents are limited and restricted in their mobility, adaptability and efficiency. The potential for identifying biological agents through a volatile organic compound (VOC) signature presents an opportunity to use detection dogs in a real-time mobile capacity for surveillance and screening strategies. However, the safe handling and access to the materials needed for training detection dogs on restricted or hazardous biological agents prevents its broader application in this field. This study evaluated the use of a polymer-based training aid in a viral detection model using bovine viral diarrhea virus mimicking biosafety level 3+ agent conditions. After the biological agent-based odor was absorbed into the polymer, the aid was rendered safe for handling through a rigorous sterilization process. The viral culture-based training aid was then used to train a cohort of detection dogs (n = 6) to discriminate agent-based target odor in culture from relevant distractor odors including non-target biological agent-based odors. Following culture-based training, dogs were tested for generalization to aids with infected animal sample-based odors across five sample types (fecal, blood, nasal, saliva, and urine). Within the context of the polymer-based training aid system, dogs were successfully trained to detect and discriminate a representative biological viral agent-based odor from distractor odors with a 97.22% (±2.78) sensitivity and 97.11% (±1.94) specificity. Generalization from the agent-based odor to sample-based odors ranged from 65.40% (±8.98) to 91.90 % (±6.15) sensitivity and 88.61% (±1.46) to 96.00% (±0.89) specificity across the sample types. The restrictive nature for mimicking the access and handling of a BSL 3+ agent presented challenges that required a strict study design uncommon to standard detection dog training and odor presentation. This study demonstrates the need to further evaluate the utility and challenges of training detection dogs to alert to biological samples using safe and manageable training aids.
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Recent advances in electrochemical biosensors for pathogen detection are reviewed. Electrochemical biosensors for pathogen detection are broadly reviewed in terms of transduction elements, biorecognition elements, electrochemical techniques, and biosensor performance. Transduction elements are discussed in terms of electrode material and form factor. Biorecognition elements for pathogen detection, including antibodies, aptamers, and imprinted polymers, are discussed in terms of availability, production, and immobilization approach. Emerging areas of electrochemical biosensor design are reviewed, including electrode modification and transducer integration. Measurement formats for pathogen detection are classified in terms of sample preparation and secondary binding steps. Applications of electrochemical biosensors for the detection of pathogens in food and water safety, medical diagnostics, environmental monitoring, and bio-threat applications are highlighted. Future directions and challenges of electrochemical biosensors for pathogen detection are discussed, including wearable and conformal biosensors, detection of plant pathogens, multiplexed detection, reusable biosensors for process monitoring applications, and low-cost, disposable biosensors.
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Bacterias/aislamiento & purificación , Técnicas Biosensibles/instrumentación , Técnicas Electroquímicas , Eucariontes/aislamiento & purificación , Técnicas Microbiológicas/instrumentación , Virus/aislamiento & purificación , Animales , Betacoronavirus/aislamiento & purificación , COVID-19 , Infecciones por Coronavirus/diagnóstico , Infecciones por Coronavirus/virología , Electrodos , Humanos , Técnicas Microbiológicas/normas , Técnicas Microbiológicas/tendencias , Pandemias , Neumonía Viral/diagnóstico , Neumonía Viral/virología , SARS-CoV-2RESUMEN
Destruction of bioweapon facilities due to explosion or fire could aerosolize highly pathogenic microorganisms. The post-event air quality assessment is conducted through air sampling. A bioaerosol sample (often collected on a filter for further culture-based analysis) also contains combustion products, which may influence the microbial culturability and, thus, impact the outcome. We have examined the interaction between spores deposited on collection filters using two simulants of Bacillus anthracis [B. thuringiensis (Bt) and B. atrophaeus (referred to as BG)] and incoming combustion products of Al as well as Mg and B·Ti (common ingredient of metalized explosives). Spores extracted from Teflon, polycarbonate, mixed cellulose ester (MCE), and gelatin filters (most common filter media for bioaerosol sampling), which were exposed to combustion products during a short-term sampling, were analyzed by cultivation. Surprisingly, we observed that aluminum combustion products enhanced the culturability of Bt (but not BG) spores on Teflon filters increasing the culturable count by more than an order of magnitude. Testing polycarbonate and MCE filter materials also revealed a moderate increase of culturability although gelatin did not. No effect was observed with either of the two species interacting on either filter media with products originated by combustion of Mg and B·Ti. Sample contamination, spore agglomeration, effect of a filter material on the spore survival, changes in the spore wall ultrastructure and germination, as well as other factors were explored to interpret the findings. The study raises a question about the reliability of certain filter materials for collecting airborne bio-threat agents in combustion environments.
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Filtros de Aire/microbiología , Aluminio/farmacología , Bacillus/aislamiento & purificación , Incendios , Modelos Teóricos , Esporas Bacterianas/aislamiento & purificación , Aerosoles , Bacillus/efectos de los fármacos , Bacillus/fisiología , Bacillus anthracis/aislamiento & purificación , Bacillus anthracis/fisiología , Bacillus thuringiensis/aislamiento & purificación , Bacillus thuringiensis/fisiología , Bioterrorismo , Boro/farmacología , Magnesio/farmacología , Viabilidad Microbiana/efectos de los fármacos , Esporas Bacterianas/efectos de los fármacos , Titanio/farmacologíaRESUMEN
Localized surface plasmon resonance (LSPR) spectroscopy and imaging are emerging biosensor technologies which tout label-free biomolecule detection at the nanoscale and ease of integration with standard microscopy setups. The applicability of these techniques can be limited by the restrictions that surface-conjugated ligands must be both sufficiently small and orientated to meet analyte sensitivity requirements. We demonstrate that orientated single domain antibodies (sdAb) can optimize nanoplasmonic sensitivity by comparing three anti-ricin sdAb constructs to biotin-neutravidin, a model system for small and highly orientated ligand studies. LSPR imaging of electrostatically orientated sdAb exhibited a ricin sensitivity equivalent to that of the biotinylated LSPR biosensors for neutravidin. These results, combined with the facts that sdAb are highly stable and readily produced in bacteria and yeast, build a compelling case for the increased utilization of sdAbs in nanoplasmonic applications.
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India of late has been vulnerable to Chemical, Biological, Radiological and Nuclear (CBRN) threat, on account of its unique geographic position. Biological threat is an imminent threat in the hands of a terrorist. The public health system of our country is overburdened due to its present role and bio-attack response is not a priority area. This paper suggests that as the prime focus is on the CR and N threats in the integrated CBRN preparedness strategy and that specialized and technical forces are needed to deal with a bio-threat; hence there is a need for a paradigm shift in policy. The emerging field of bio-threat needs to be delinked from the joint family of 'CBRN', with consequent structural and functional changes. A separate specialized cadre needs to be formed for dealing with bio-threat, created from the pool of doctors and non-medical scientists from the AFMS and the DRDO. Structural changes are needed in the organization, to bring in the resources of NCDC, New Delhi for enhanced disease surveillance capacity and creation of a bio-threat mitigation node in the AFMC, Pune.
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Class II viral fusion proteins are present on the envelope of flaviviruses and togaviruses, viruses that often cause tropical and subtropical diseases. These proteins use a second membrane protein as a molecular chaperone to assist their folding and to ensure proper function during viral assembly, maturation, and infection. Recent progress in structural studies of dengue viruses has revealed how the chaperone pre-membrane (prM) protein guides viral maturation and how pH is sensed in both the maturation and infection processes. Drastic conformation changes and reorganization of these viral membrane proteins occur during the transition from their metastable to stable structural states in a unidirectional, entropy-driven process.
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Virus del Dengue/enzimología , Entropía , Chaperonas Moleculares/metabolismo , Pliegue de Proteína , Proteínas del Envoltorio Viral/metabolismo , Proteínas Virales de Fusión/metabolismo , Virus del Dengue/efectos de los fármacos , Concentración de Iones de Hidrógeno , Conformación ProteicaRESUMEN
BACKGROUND: Specific screening methods for complex food matrices are needed that enable unambiguous and sensitive detection of bio threat agents (BTAs) such as Bacillus anthracis spores and microbial toxins (e.g. staphylococcal enterotoxin B (SEB) and clostridial botulinum neurotoxins (BoNTs)). The present study describes an image-based 96-well Meso Scale Discovery (MSD) electrochemiluminescence (ECL) assay for simultaneous detection of BTAs in dairy milk products. RESULTS: The limit of detection of this ECL assay is 40 pg mL⻹ for BoNT/A complex, 10 pg mL⻹ for SEB and 40000 CFU mL⻹ for Bacillus anthracis spores in dairy milk products. The ECL assay was successfully applied to screen type A Clostridium botulinum outbreak strains. CONCLUSION: The results of the study indicate that this ECL assay is very sensitive, rapid (<6 h) and multiplex in nature. The ECL assay has potential for use as an in vitro screening method for BTAs over other comparable immunoassays.