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A Review on L-Asparaginase
Published in Se-Kwon Kim, Marine Biochemistry, 2023
Assessing cell membrane integrity is one of the most common ways to determine the viability of the cell and its cytotoxic effects. Compounds that possess cytotoxic effects often compromise cell membrane integrity. Vital dyes, such as propidium iodide or trypan blue, are normally excluded from the inside of healthier cells; however, if the cell membrane is negotiated, they easily cross the membrane and stain the intracellular components (Riss et al., 2004). The extracellular enzyme possessed a cytotoxic effect on HL60 cell line (Hari Krishnan et al., 2016). The traditional methods of identifying the bacterial strain rely on culturing technique. Such techniques have certain limitations. In order to overcome those limitations, molecular characterization came into force. 16s rRNA sequencing can give much more information than culturing methods. Metagenomics is another field that involves the study and analysis of microbial communities from the surrounding environment without culturing. It also affords the potential to determine novel enzymes through function-based screening. Hence, metagenomics has given the scientific community with a range of novel enzymes (Zhang and Kim, 2010).
Probiotics as HRV Vaccine Adjuvants in Gn Pigs
Published in Lijuan Yuan, Vaccine Efficacy Evaluation, 2022
The Gn pig model is a valuable animal model for the study of probiotic−virus host interaction because of the many similarities between human and porcine intestinal physiology and mucosal immune system (Meurens et al., 2012). The Gn status prevents confounding factors from commensal microflora that are present in conventionally reared animals or humans. Unlike Gn mice, Gn pigs are devoid of maternal antibodies, thus providing an immunologically naive background that allows clear identification of the immune responses to a single vaccine in hosts colonized with a qualitatively and quantitatively defined probiotic bacterial strain (Butler, 2009; Yuan and Saif, 2002). Although data from studies of Gn animal models may not be generalized directly to normal animals or humans, Gn animals provide a medium in which investigating the complex interrelationships of the host and its associated microbes become possible (Coates, 1975). Our findings provide a good starting point for the identification of the optimal dosage of a probiotic adjuvant. Nonetheless, the optimal dosage needs to be confirmed in conventionalized or humanized Gn pigs and human clinical trials to achieve the appropriate adjuvant effect for rotavirus and other vaccines.
Infectious Diseases
Published in Lyle D. Broemeling, Bayesian Analysis of Infectious Diseases, 2021
Once in every several million cell divisions, a mutation produces immune bacteria, which is immune to an antibiotic drug. This occurs because the mutation changes the bacteria’s genetic code, and consequently its ability to use certain chemicals for its activities. Some of the causes of mutations are radiation from space that enter the earth’s environment, as well as some atmospheric chemicals. As a result of the mutation, all bacteria that stem from the immune germ will be resistant to the drug unless it mutates again to make the strain susceptible again. Thus, whenever a new antibiotic is developed, there is a small probability the bacteria will develop an immunity against it. Since mutations are fairly rare, there is a good chance of fighting a bacterial disease with another drug before future strains become resistant. Some members of the bacterial strain are resistant to certain drugs naturally. In time, they can eventually become selected via evolution and become the dominant drug-resistant forms of a pathogenic strain. More importantly, some bacteria can pass on their drug resistance to another stain by “infection”. Since the passing of resistance factors does not depend upon the lengthy process of mutation, it poses a much greater problem of drug immunity. Thus, doctors must prescribe more than one antibiotic to fight certain diseases, in the hope that this will retard bacterial resistance.
Mechanistic study of copper oxide, zinc oxide, cadmium oxide, and silver nanoparticles-mediated toxicity on the probiotic Lactobacillus reuteri
Published in Drug and Chemical Toxicology, 2023
Aya M. Eid, Osama M. Sayed, Walaa Hozayen, Tarek Dishisha
L. reuteri, a member of gut microbiota, has antimicrobial, anti-inflammatory, and immunoregulatory functions. It is crucial to eliminate infections and prevent gastrointestinal disorders and diseases in other tissues. Therefore, factors that affect their growth and metabolic activity will harm their host (Mu et al.2018). Nanomaterials, with their growing diversity, unique features, and unlimited applications, pose a threat to the environment and human health, which has become a growing topic of research (Rekulapally et al.2019). To our knowledge, no studies have been performed on the same bacterial strain (L. reuteri) yet; however, several studies have been performed on different lactobacilli strains (Tian et al.2018) and other bacteria (Chen et al.2019, Liao et al.2019, Leareng et al.2020).
Lessons from a mature acellular pertussis vaccination program and strategies to overcome suboptimal vaccine effectiveness
Published in Expert Review of Vaccines, 2022
Ousseny Zerbo, Bruce Fireman, Nicola P. Klein
Developing strategies for the best use of current pertussis vaccines is key to preventing and mitigating outbreaks, however the ideal long-term goal is to have pertussis vaccines that protect all vaccinated individuals for a long period of time, possibly leading to disease eradication. In the pursuit of new pertussis vaccines, developers should consider taking advantage of the new platforms used to develop COVID-19 vaccines such as mRNA vaccines, which induce broad immune response and appear to be highly effective against COVID-19 [99–101]. Although the duration of protection following primary doses of mRNA COVID-19 vaccines seems to be short [102], additional booster might provide long-term immunity. If needed, the use of mRNA platforms would also allow for rapid development of vaccines against new Bordetella pertussis strains. We hope that mRNA vaccines can prevent colonization in order to prevent bacterial strain selection pressure as seen with acellular pertussis vaccines. In addition, other subunits and viral vector platforms used to develop COVID-19 vaccines should also be explored as the basis for new pertussis vaccines.
The war against bacteria, from the past to present and beyond
Published in Expert Review of Anti-infective Therapy, 2022
Lucrezia Bottalico, Ioannis Alexandros Charitos, Maria Assunta Potenza, Monica Montagnani, Luigi Santacroce
A bacterial strain is resistant to a drug when it can multiply in the presence of drug concentrations inhibitory for most of the stems of the same species, or equal to the maximum ones achievable during therapeutic use. The incidence and selection of resistance-inducing mutations in several bacterial strains has progressively increased due to the misuse of antibiotics, depending on their empirical use (treatment of a disease from unknown etiological agents), prophylaxis in surgery, inappropriate use of molecules with a broad spectrum of action, auxinic use in farm animals, administration in pediatric patients with viral infections and improper patient compliance [3]. Clinical significance of resistance implies that resistant strains survive in the presence of antibiotic serum concentrations reached with administration of standard therapeutic doses. Resistance predicts the possible failure of antibiotic therapy (Table 3) [126].