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Single-Molecule Analysis by Biological Nanopores
Published in Shuo Huang, Single-Molecule Tools for Bioanalysis, 2022
Biological nanopores are a category of transmembrane porins with a considerably large pore lumen measuring from 1 to 5 nm in diameter, which are utilized for single-molecule sensing. Reported biological nanopores including S. aureus α-HL [19], MspA [36], Escherichia coli ferric hydroxamate uptake protein A (FhuA) [37], bacteriophage phi29 connector [38], E. coli cytolysin A (ClyA) [39], E. coli outer membrane protein G (OmpG) [40], E. coli outer membrane protein F (OmpF) [41], Actinia fragacea fragaceatoxin C (Frac) [42], E. coli curli production assembly/transport component CsgG (CsgG) [43], and human specificity protein 1 (Sp1) [44] could be similarly utilized as single-molecule sensors (Figure 1.2). The α-HL, which is the most studied biological nanopore, is the most robust nanopore sensor used to date. In nature, it is an exotoxin secreted by the human pathogen S. aureus bacterium. In its heptameric form, α-HL appears as a mushroom-shaped protein (with a cap domain and a stem domain) and a molecular weight of 232.4 kDa. The stem domain, which is embedded in the lipid membrane, is composed of 14 antiparallel β strands that form a cylindrical channel for molecular transportation. The narrowest spot of the cylindrical channel is ~1.4 nm in diameter. It serves as the recognition site for molecular identity discrimination [16] and permits passage only of ssDNA. The cap domain, which has an inner diameter of ~4.5 nm, is capable of accommodating a short fragment of dsDNA.
Walkerton
Published in Jamie Bartram, Rachel Baum, Peter A. Coclanis, David M. Gute, David Kay, Stéphanie McFadyen, Katherine Pond, William Robertson, Michael J. Rouse, Routledge Handbook of Water and Health, 2015
Steve E. Hrudey, Elizabeth J. Hrudey
By Saturday, May 20, on a holiday long weekend, the outbreak had severely overloaded the Walkerton hospital which had fielded more than 120 calls from concerned residents, with more than half reporting bloody diarrhea. Meanwhile, the Owen Sound hospital had found a presumptive positive for the serious human pathogen, E. coliO157:H7, in one of the children admitted there on Thursday, May 18. The emerging outbreak kept the public health staff fully engaged. The general manager received two more calls from the public health unit to inquire about the chlorine residuals he was measuring. Public health officials were reassured that measureable chlorine residuals were appearing in the distribution system assuming that must indicate that the water was safe. The medical officer had been out of town to spend the long weekend with his wife who had been recently diagnosed with cancer, but the health unit administrator contacted him and requested he return to help the local health unit deal with the emerging crisis.
Pathogens in Wastewater and Biosolids
Published in Eliot Epstein, LAND APPLICATION of SEWAGE SLUDGE and BIOSOLIDS, 2002
A human pathogen is any virus, microorganism, or substance capable of causing disease (Stedman’s Medical Dictionary, 1977). By this definition, bacteria, parasites, viruses, microbial substances (endotoxins), fungi and other organisms are pathogens. The two general categories are primary and secondary pathogens. Primary pathogens, such as bacteria, parasites and viruses, can invade and infect healthy humans (Burge and Millner, 1980). Secondary pathogens invade and infect a debilitated or an immunosuppressed individual. Often secondary pathogens, such as fungi, are termed opportunistic pathogens, since they infect those who have suffered disease, causing severe debilitation.
Drying of Vaccines and Biomolecules
Published in Drying Technology, 2022
Bhaskar N. Thorat, Ayantika Sett, A. S. Mujumdar
Spray drying process is a extensively used for manufacturing fine particles, those are suitable for pulmonary delivery of active pharmaceutical ingredients using breath activator device,[36] generally known as Dry Powder Inhalers (DPIs).[37] The heat sensitive biological products such as peptides and proteins are routine processed in a spray dryer.[38–41]. Spray dried products requires lesser handling and therefore fewer downstream processing steps as compared to freeze dried products and also it is more energy efficient. Matinkhoo et al.[41] Prepared spray dried powder of Myoviridaephages using a Nano Spray Dryer. The dried phage molecule has an activity against an opportunistic human pathogen, B. cepacia. The dried phage has been used in the formulation of inhalation therapy.[34] Though, it is difficult to scale up the spray dryers using ultrasonic atomizers, keeping the energy requirement to its optimum low and also due to lower recovery of the energy, the industrial scale manufacturing of mono-dispersed particles in sub-micron range has been possible with the advent of ink-jet atomization technology.[38]
Carbon nanomaterials: a new way against tuberculosis
Published in Expert Review of Medical Devices, 2019
Flavio De Maio, Valentina Palmieri, Marco De Spirito, Giovanni Delogu, Massimiliano Papi
Recently, our group proposed a new system based on GO nanoparticles for Mycobacteria entrapment [98]. Importantly this new approach was tested on the not pathogen Ms and, for the first time on the human pathogen, Mtb without functionalization with drugs. The GO is a bidimensional carbon material largely studied for its unique interactions with bacteria and fungi [99]. The flat nature of GO makes this material able to cut bacterial membranes and act as nano-knife as well as causing membrane perturbation and redox stress induction [100]. This action, however, is limited when the size of the microorganisms is exceeding the lateral size of the GO or when their cell wall is extremely thick like in fungi. Additionally, GO activity is significantly constrained when this CNM is used in solutions rich in cations or proteins [33] that cause instability and aggregation of the flakes [90]. This instability is responsible of the so-called bacteria ‘trapping effect’ GO mediated, reported also for Ms and Mtb: bacteria are blocked and confined in a carbon web [98]. GO impairs Mtb and Ms entry into macrophages and reduces the intracellular mycobacterial load by trapping without affecting host cell viability (Figure 3).
Prevalence and diversity of blaTEM, blaSHV and blaCTX-M variants among multidrug resistant Klebsiella spp. from an urban riverine environment in India
Published in International Journal of Environmental Health Research, 2019
Aftab Hossain Mondal, Mohammad Tahir Siddiqui, Insha Sultan, Qazi Mohd. Rizwanul Haq
The present study highlights high prevalence of ESBL producing Klebsiella spp. exhibiting multidrug resistance (MDR) phenotype in Delhi stretch of river Yamuna. Identification of ESBLs determinants blaTEM, blaSHV and blaCTX-M and diversity of their variants in Klebsiella spp. from natural aquatic environment suggest that this river is a potent reservoir for antibiotics resistant bacteria and their associated genes which may contribute in emergence of human pathogen with novel resistance mechanisms. To the best of our knowledge, occurrence of blaCTX-M-188 and blaTEM-206 in environmental isolates of K. pneumoniae has not been reported earlier. Furthermore, identification of variants blaTEM-206, blaSHV-27 and blaSHV-144 from Klebsiella spp. and blaTEM-116 from K. quasipneumoniae and K. variicola are the first reports from India. The results of present study suggest that serious contamination of ESBL producing MDR Klebsiella spp. in Indian river aquatic environment is potential risk to the public health and more studies are required to investigate their prevalence in other environments.