Immobilization of Rhus vernicifera laccase on sepiolite; effect of chitosan and copper modification on laccase adsorption and activity

The enzyme laccase, a multi-copper oxidase found in many plants and fungi, can be used in water treatment processes for the removal of pollutants. Commercially available laccase, derived from Rhus vernicifera, was adsorbed on sepiolite, sepiolite modified with chitosan, sepiolite plus Cu(II), and sepiolite modified with both chitosan and Cu(II) to investigate enzymatic activity. Adsorption of laccase on unmodified sepiolite increased its activity by 250 +/- 40% compared to the non-adsorbed enzyme, whereas for sepiolite-Cu-chitosan and sepiolite chitosan the activity was enhanced by up to 700% and 500%, respectively. The stronger enhancement for the Cu-containing adsorbent suggests that exchangeable Cu has an effect on the adsorbed laccase. Desorption of the adsorbed laccase was < 10%, and the non-desorbed enzyme retained high activity, indicating robust adsorption. This study suggests that chitosan-sepiolite based composites might be used as efficient support for laccase scaffolding and immobilization, thus providing in an effective adsorbent surface for catalytic oxidation of organic pollutants sensitive to laccase activity.European Union's [FP7-REGPOT-2012-2013-1, 316157]24 month embargo; published online: 10 November 2017This item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]

Development and Validation of an Innovative Analytical Approach for the Quantitation of Tris(Hydroxymethyl)Aminomethane (TRIS) in Pharmaceutical Formulations by Liquid Chromatography Tandem Mass Spectrometry

A novel COVID-19 vaccine (BriLife&reg;) has been developed by the Israel Institute for Biological Research (IIBR) to prevent the spread of the SARS-CoV-2 virus throughout the population in Israel. One of the components in the vaccine formulation is tris(hydroxymethyl)aminomethane (tromethamine, TRIS), a buffering agent. TRIS is a commonly used excipient in various approved parenteral medicinal products, including the mRNA COVID-19 vaccines produced by Pfizer/BioNtech and Moderna. TRIS is a hydrophilic basic compound that does not contain any chromophores/fluorophores and hence cannot be retained and detected by reverse-phase liquid chromatography (RPLC)-ultraviolet (UV)/fluorescence methods. Among the few extant methods for TRIS determination, all exhibit a lack of selectivity and/or sensitivity and require laborious sample treatment. In this study, LC&ndash;mass spectrometry (MS) with its inherent selectivity and sensitivity in the multiple reaction monitoring (MRM) mode was utilized, for the first time, as an alternative method for TRIS quantitation. Extensive validation of the developed method demonstrated suitable specificity, linearity, precision, accuracy and robustness over the investigated concentration range (1.2&ndash;4.8 mg/mL). Specifically, the R2 of the standard curve was &gt;0.999, the recovery was &gt;92%, and the coefficient of variance (%CV) was &lt;12% and &lt;6% for repeatability and intermediate precision, respectively. Moreover, the method was validated in accordance with strict Good Manufacturing Practice (GMP) guidelines. The developed method provides valuable tools that pharmaceutical companies can use for TRIS quantitation in vaccines and other pharmaceutical products

Phage Therapy Potentiates Second-Line Antibiotic Treatment against Pneumonic Plague

Plague pandemics and outbreaks have killed millions of people during the history of humankind. The disease, caused by the bacteria Yersinia pestis, is currently treated effectively with antibiotics. However, in the case of multidrug-resistant (MDR) bacteria, alternative treatments are required. Bacteriophage (phage) therapy has shown efficient antibacterial activity in various experimental animal models and in human patients infected with different MDR pathogens. Here, we evaluated the efficiency of фA1122 and PST phage therapy, alone or in combination with second-line antibiotics, using a well-established mouse model of pneumonic plague. Phage treatment significantly delayed mortality and limited bacterial proliferation in the lungs. However, the treatment did not prevent bacteremia, suggesting that phage efficiency may decrease in the circulation. Indeed, in vitro phage proliferation assays indicated that blood exerts inhibitory effects on lytic activity, which may be the major cause of treatment inefficiency. Combining phage therapy and second-line ceftriaxone treatment, which are individually insufficient, provided protection that led to the survival of all infected animals—a synergistic protective effect that represents a proof of concept for efficient combinatorial therapy in an emergency event of a plague outbreak involving MDR Y. pestis strains

Phage Therapy Potentiates Second-Line Antibiotic Treatment against Pneumonic Plague

Plague pandemics and outbreaks have killed millions of people during the history of humankind. The disease, caused by the bacteria Yersinia pestis, is currently treated effectively with antibiotics. However, in the case of multidrug-resistant (MDR) bacteria, alternative treatments are required. Bacteriophage (phage) therapy has shown efficient antibacterial activity in various experimental animal models and in human patients infected with different MDR pathogens. Here, we evaluated the efficiency of &#1092;A1122 and PST phage therapy, alone or in combination with second-line antibiotics, using a well-established mouse model of pneumonic plague. Phage treatment significantly delayed mortality and limited bacterial proliferation in the lungs. However, the treatment did not prevent bacteremia, suggesting that phage efficiency may decrease in the circulation. Indeed, in vitro phage proliferation assays indicated that blood exerts inhibitory effects on lytic activity, which may be the major cause of treatment inefficiency. Combining phage therapy and second-line ceftriaxone treatment, which are individually insufficient, provided protection that led to the survival of all infected animals&mdash;a synergistic protective effect that represents a proof of concept for efficient combinatorial therapy in an emergency event of a plague outbreak involving MDR Y. pestis strains