A Simple Validated Method for the Estimation of Pepsin Activity in Microtiter Array for the INFOGEST Protocol

The INFOGEST protocol has been widely used as a static in-vitro simulation of gastrointestinal food digestion for bioaccessibility assessments on bioactive compounds. The standardization of the activity of several enzymes, such as pepsin, via UV-spectrophotometry of digested hemoglobin at 280 nm is a key step in the protocol. Standardization is a crucial stage since it is necessary to determine the quantity of enzyme to be added to the sample for digestion. However, this method is yet to be analytically validated; it requires quartz cuvettes and large volumes of samples and is time-consuming. Thus, we reviewed and adapted a well-known colorimetric method in microplates array by using the Folin-Ciocalteu reagent, and this study is the first to report for miniaturization of this method, the advantages of which include its automation, ease of use, the low volume of samples required, the minimal use of reagents, and speed. This method was compared to the traditional UV method, and the comparison results show no statistical difference between the inter day means for each group (p > 0.05). The proposed method was validated, showing high reproducibility (8% as inter-day CV) and statistically comparable results with the traditional UV spectrophotometric method.

Identification of Potential Therapeutic Targets on the Level of DNA/mRNAs, Proteins and Metabolites: A Systematic Mapping Review of Scientific Texts' Fragments from Open Targets

Database records contain useful information, which is readily available, but, unfortunately, limited compared to the source (publications). Our study reviewed the text fragments supporting the association between the biological macromolecules and diseases from Open Targets to map them on the biological level of study (DNA/RNA, proteins, metabolites). We screened records using a dictionary containing terms related to the selected levels of study, reviewed 600 hits manually and used machine learning to classify 31,260 text fragments. Our results indicate that association studies between diseases and macromolecules conducted on the level of DNA and RNA prevail, followed by the studies on the level of proteins and metabolites. We conclude that there is a clear need to translate the knowledge from the DNA/RNA level to the evidence on the level of proteins and metabolites. Since genes and their transcripts rarely act in the cell by themselves, more direct evidence may be of greater value for basic and applied research.

Bioremediation of reactive orange 16 by industrial effluent-adapted bacterial consortium VITPBC6: process optimization using response surface methodology (RSM), enzyme kinetics, pathway elucidation, and detoxification

Textile effluent is one of the most hazardous industrial pollutant sources. It is generated in huge volumes and contains a wide array of toxicants. Reactive azo dyes, which are xenobiotic compounds, are predominantly utilized by textile industries for dyeing cotton, viscose, wool, and silk. The conventional physicochemical treatments used by industrial effluent treatment plants are ineffective in dye degradation. The present study thus attempted to find a potential treatment for reactive azo dyes. A novel bacterial consortium VITPBC6 was constructed with the most potent and compatible reactive orange 16 (RO-16) decolorizing isolates of tannery and textile effluents, and the isolates were identified as Bacillus flexus VITSP6, Bacillus paraflexus VITSPB7, Bacillus megaterium VITSPB9, Bacillus firmus VITEPB1, B. flexus VITEPB2, and Bacillus aryabhattai VITEPB3. The physicochemical factors of RO-16 decolorization were optimized by response surface methodology. Consortium VITPBC6 was able to tolerate a high concentration of RO-16 up to 800 mg L^-1. A cocktail of enzymes including azoreductase, tyrosinase, laccase, lignin peroxidase, and manganese peroxidase was involved in RO-16 degradation by VITPBC6. Consortium VITPBC6 degraded RO-16 following zero-order reaction. The enzymes of consortium VITPBC6 had a V_max of 352 mg L^-1 day^-1 for RO-16 degradation; however, the K_m value was high. VITPBC6 biodegraded RO-16 resulting in the formation of small aromatic compounds. Lastly, different toxicity assays conducted with untreated RO-16 and its corresponding biodegraded metabolite revealed that the toxicity of biodegraded metabolites was significantly lower than the untreated dye.

Emerging Biosensing Technologies towards Early Sepsis Diagnosis and Management

Sepsis is defined as a systemic inflammatory dysfunction strictly associated with infectious diseases, which represents an important health issue whose incidence is continuously increasing worldwide. Nowadays, sepsis is considered as one of the main causes of death that mainly affects critically ill patients in clinical settings, with a higher prevalence in low-income countries. Currently, sepsis management still represents an important challenge, since the use of traditional techniques for the diagnosis does not provide a rapid response, which is crucial for an effective infection management. Biosensing systems represent a valid alternative due to their characteristics such as low cost, portability, low response time, ease of use and suitability for point of care/need applications. This review provides an overview of the infectious agents associated with the development of sepsis and the host biomarkers suitable for diagnosis and prognosis. Special focus is given to the new emerging biosensing technologies using electrochemical and optical transduction techniques for sepsis diagnosis and management.

Glucose Oxidase and Catalase Activities in Honey Samples from the Southwestern Region of Saudi Arabia

The activity of honey enzymes are affected by floral and geographical origins, climate conditions, honeybee species, health and nutrition. This article investigated the effect of floral and geographical origins on the activity of glucose oxidase (GOx) and catalase (CAT) enzymes in honey samples from the southwestern region of Saudi Arabia. Moreover, the moisture, total sugars, pH and conductivity were measured as quality parameters. The floral origin of the honey samples was determined microscopically while the quality parameters were measured according to the methods of international honey commission. The activity of the honey enzyme was determined following the instructions of the Megazyme International kits. The obtained results were statistically analyzed by the statistical Package for Social Sciences (SPSS, v.20). The GOx activity of the Acacia, Ziziphus and polyfloral honey samples of the Asir region were (5.19 ± 2.33 U/g), (4.01 ± 1.17 U/g) and (5.69 ± 1.67 U/g), respectively. The Acacia, Ziziphus and polyfloral honey samples from the Jazan region had GOx activities of (6.85 ± 0.47 U/g), (10.48 ± 9.22 U/g) and (5.31 ± 2.7 U/g), respectively. The geographical origin significantly affected the GOx activity of Ziziphus honey (p-value = 0.005) and the GOx activity of the Ziziphus honey was significantly more than that of the polyfloral honey of the Jazan region (p-value = 0.009). With regard to the CAT activity in Asir region honey samples, the mean values of the Acacia, Ziziphus and polyfloral honeys were (2.89 ± 1.08 U/g), (3.58 ± 1.59 U/g) and (2.84 ± 1.24 U/g), respectively. The mean values of the CAT activity in the Jazan honey samples were Acacia (4.35 ± 1.01 U/g), Ziziphus (3.94 ± 0.04 U/g) and polyfloral (3.43 ± 0.67 U/g). The geographical origin significantly affected the CAT activity in Acacia honey (p-value = 0.014). The geographical and floral origins had significant effects on the activity of the honey GOx and CAT enzymes.

Production, Optimization, and Partial Purification of Alkali-Thermotolerant Proteases from Newly Isolated Bacillus subtilis S1 and Bacillus amyloliquefaciens KSM12

Proteases that can remain active under extreme conditions such as high temperature, pH, and salt concentration are widely applicable in the commercial sector. The majority of the proteases are rendered useless under harsh conditions in industries. Therefore, there is a need to search for new proteases that can tolerate and function in harsh conditions, thus improving their commercial value. In this study, 142 bacterial isolates were isolated from diverse alkaline soil habitats. The two highest protease-producing bacterial isolates were identified as Bacillus subtilis S1 and Bacillus amyloliquefaciens KSM12, respectively, based on 16S rRNA sequencing. Optimal protease production was detected at pH 8, 37 °C, 48 h, 5% (w/v) NaCl for Bacillus subtilis S1 (99.8 U/mL) and pH 9, 37 °C, 72 h, 10% (w/v) NaCl for Bacillus amyloliquefaciens KSM12 (94.6 U/mL). The molecular weight of these partially purified proteases was then assessed on SDS-PAGE (17 kDa for Bacillus subtilis S1 and 65 kDa for Bacillus amyloliquefaciens KSM12), respectively. The maximum protease activity for Bacillus subtilis S1 was detected at pH 8, 40 °C, and for Bacillus amyloliquefaciens KSM12 at pH 9, 60 °C. These results suggest that the proteases secreted by Bacillus subtilis S1 and Bacillus amyloliquefaciens KSM12 are suitable for industries working in a highly alkaline environment.

Glossary of terms used in physical organic chemistry (IUPAC Recommendations 2021)

This Glossary contains definitions, explanatory notes, and sources for terms used in physical organic chemistry. Its aim is to provide guidance on the terminology of physical organic chemistry, with a view to achieving a consensus on the meaning and applicability of useful terms and the abandonment of unsatisfactory ones. Owing to the substantial progress in the field, this 2021 revision of the Glossary is much expanded relative to the previous edition, and it includes terms from cognate fields.

High-yield synthesis and purification of recombinant human GABA transaminase for high-throughput screening assays

Many studies have focussed on modulating the activity of γ-aminobutyric acid transaminase (GABA-T), a GABA-catabolizing enzyme, for treating neurological diseases, such as epilepsy and drug addiction. Nevertheless, human GABA-T synthesis and purification have not been established. Thus, biochemical and drug design studies on GABA-T have been performed by using porcine GABA-T mostly and even bacterial GABA-T. Here we report an optimised protocol for overexpression of 6xHis-tagged human GABA-T in human cells followed by a two-step protein purification. Then, we established an optimised human GABA-T (0.5 U/mg) activity assay. Finally, we compared the difference between human and bacterial GABA-T in sensitivity to two irreversible GABA-T inhibitors, gabaculine and vigabatrin. Human GABA-T in homodimeric form showed 70-fold higher sensitivity to vigabatrin than bacterial GABA-T in multimeric form, indicating the importance of using human GABA-T. In summary, our newly developed protocol can be an important first step in developing more effective human GABA-T modulators.

Functional and structural characterization of a novel GH3 β-glucosidase from the gut metagenome of the Brazilian Cerrado termite Syntermes wheeleri

In this study, a GH3 family β-glucosidase (Bgl7226) from metagenomic sequences of the Syntermes wheeleri gut, a Brazilian Cerrado termite, was expressed, purified and characterized. The enzyme showed two optimum pHs (pH 7 and pH 10), and a maximum optimum temperature of about 40 °C using 4-Nitrophenyl β-D-glucopyranoside (pNPG) as substrate. Bgl7226 showed higher enzymatic activity at basic pH, but higher affinity (K_m) at neutral pH. However, at neutral pH the Bgl7226 enzyme showed higher catalytic efficiency (k_cat/K_m) for pNPG substrate. Predictive analysis about the enzyme structure-function relationship by sequence alignment suggested the presence of multi-domains and conserved catalytic sites. Circular dichroism results showed that the secondary structure composition of the enzyme is pH-dependent. Small conformational changes occurred close to the optimum temperature of 40 ^o C, and seem important for the highest activity of Bgl7226 observed at pH 7 and 10. In addition, the small transition in the unfolding curves close to 40 ^o C is typical of intermediates associated with proteins structured in several domains. Bgl7226 has significant β-glucosidase activity which could be attractive for biotechnological applications, such as plant roots detoxification; specifically, our group is interested in cassava roots (Manihot esculenta) detoxification.

Vocabulary of radioanalytical methods (IUPAC Recommendations 2020)

These recommendations are a vocabulary of basic radioanalytical terms which are relevant to radioanalysis, nuclear analysis and related techniques. Radioanalytical methods consider all nuclear-related techniques for the characterization of materials where ‘characterization’ refers to compositional (in terms of the identity and quantity of specified elements, nuclides, and their chemical species) and structural (in terms of location, dislocation, etc. of specified elements, nuclides, and their species) analyses, involving nuclear processes (nuclear reactions, nuclear radiations, etc.), nuclear techniques (reactors, accelerators, radiation detectors, etc.), and nuclear effects (hyperfine interactions, etc.). In the present compilation, basic radioanalytical terms are included which are relevant to radioanalysis, nuclear analysis and related techniques.

Sensors and microarrays in protein biomarker monitoring: an electrochemical perspective spots

The development of clinically applicable portable sensors and multiplex protein biomarker assays is one of the most important goals of laboratory medicine today. Sensing strategies based on electrochemical devices are discussed in this overview, with special emphasis on detection principles derived from voltammetry, electrogenerated chemiluminescence, bipolar electrochemistry and impedance-based measurements. Up-to-date examples of electrochemical methods in biomedical research and development are highlighted here, including critical evaluation and future directions of the analysis, development and validation of new protein biomarkers.

Terminology of electrochemical methods of analysis (IUPAC Recommendations 2019)

Recommendations are given concerning the terminology of methods used in electroanalytical chemistry. Fundamental terms in electrochemistry are reproduced from previous PAC Recommendations, and new and updated material is added for terms in electroanalytical chemistry, classification of electrode systems, and electroanalytical techniques.