Dietary Flaxseed Oil Supplementation Mitigates the Effect of Lead on the Enzymes of Carbohydrate Metabolism, Brush Border Membrane, and Oxidative Stress in Rat Kidney Tissues

Lead is a heavy metal widely distributed in the environment. Lead is a ubiquitous environmental toxin that is capable of causing numerous acute and chronic illnesses. Human and animal exposure demonstrates that lead is nephrotoxic. However, attempts to reduce lead-induced nephrotoxicity were not found suitable for clinical use. Recently, flaxseed oil (FXO), a rich source of ω-3 fatty acids and lignans, has been shown to prevent/reduce the progression of certain types of cardiovascular and renal disorders. In view of this, the present study investigates the protective effect of FXO on lead acetate (PbAc)-induced renal damage. Rats were pre-fed normal diet and the diet rich in FXO for 14 days, and then, four doses of lead acetate (25 mg/kg body weight) were administered intraperitoneally while still on diet. Various serum parameters, enzymes of carbohydrate metabolism, brush border membrane (BBM), and oxidative stress were analyzed in rat kidney. PbAc nephrotoxicity was characterized by increased serum creatinine and blood urea nitrogen. PbAc increased the activities of lactate dehydrogenase and NADP-malic enzyme, whereas it decreased malate and glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, fructose-1, 6-bisphosphatase, and BBM enzyme activities. PbAc caused oxidant/antioxidant imbalances as reflected by increased lipid peroxidation and decreased activities of superoxide dismutase, glutathione peroxidase, and catalase. In contrast, FXO alone enhanced the enzyme activities of carbohydrate metabolism, BBM, and antioxidant defense system. FXO feeding to PbAc-treated rats markedly enhanced resistance to PbAc-elicited deleterious effects. In conclusion, dietary FXO supplementation ameliorated PbAc-induced specific metabolic alterations and oxidative damage by empowering antioxidant defense mechanism and improving BBM integrity and energy metabolism.     

Dimerization of an aptamer generated from Ligand-guided selection (LIGS) yields a high affinity scaffold against B-cells

Nucleic Acid Aptamers (NAAs) are a class of synthetic DNA or RNA molecules that bind specifically to their target. We recently introduced an aptamer termed R1.2 against membrane Immunoglobulin M (mIgM) expressing B-cell neoplasms using Ligand Guided Selection (LIGS). While LIGS-generated aptamers are highly specific, their lower affinity prevents aptamers from being used for translational applications. Highly specific aptamers with higher affinity can increase targetability, boosting the application of aptamers as diagnostic and therapeutic molecules. Herein, we report that dimerization of R1.2, an aptamer generated from LIGS, leads to high affinity variants without compromising the specificity. Three dimeric aptamer analogues with variable linker lengths were designed to evaluate the effect of linker length in affinity. The optimized dimeric R1.2 against cultured B-cell neoplasms, four donor B-cell samples and mIgM-positive Waldenström's Macroglobulinemia (WM) showed specificity. Furthermore, confocal imaging of dimeric aptamer and anti-IgM antibody in purified B-cells suggests co-localization. Binding assays against IgM knockout Burkitt's Lymphoma cells utilizing CRISPR/Cas9 further validated specificity of dimeric R1.2. Collectively, our findings show that LIGS-generated aptamers can be re-engineered into dimeric aptamers with high specificity and affinity, demonstrating wide-range of applicability of LIGS in developing clinically practical diagnostic and therapeutic aptamers.     

Ten simple rules to host an inclusive conference

Conferences are spaces to meet and network within and across academic and technical fields, learn about new advances, and share our work. They can help define career paths and create long-lasting collaborations and opportunities. However, these opportunities are not equal for all. This article introduces 10 simple rules to host an inclusive conference based on the authors’ recent experience organizing the 2021 edition of the useR! statistical computing conference, which attracted a broad range of participants from academia, industry, government, and the nonprofit sector. Coming from different backgrounds, career stages, and even continents, we embraced the challenge of organizing a high-quality virtual conference in the context of the Coronavirus Disease 2019 (COVID-19) pandemic and making it a kind, inclusive, and accessible experience for as many people as possible. The rules result from our lessons learned before, during, and after the organization of the conference. They have been written mainly for potential organizers and selection committees of conferences and contain multiple practical tips to help a variety of events become more accessible and inclusive. We see this as a starting point for conversations and efforts towards building more inclusive conferences across the world. * Translated versions of the English abstract and the list of rules are available in 10 languages in S1 Text: Arabic, French, German, Italian, Japanese, Korean, Portuguese, Spanish, Tamil, and Thai.     

Thermostability enhancement of polyethylene terephthalate degrading PETase using self- and nonself-ligating protein scaffolding approaches

Polyethylene terephthalate (PET) hydrolase enzymes show promise for enzymatic PET degradation and green recycling of single-use PET vessels representing a major source of global pollution. Their full potential can be unlocked with enzyme engineering to render activities on recalcitrant PET substrates commensurate with cost-effective recycling at scale. Thermostability is a highly desirable property in industrial enzymes, often imparting increased robustness and significantly reducing quantities required. To date, most engineered PET hydrolases show improved thermostability over their parental enzymes. Here, we report engineered thermostable variants of Ideonella sakaiensis PET hydrolase enzyme (IsPETase) developed using two scaffolding strategies. The first employed SpyCatcher-SpyTag technology to covalently cyclize IsPETase, resulting in increased thermostability that was concomitant with reduced turnover of PET substrates compared to native IsPETase. The second approach using a GFP-nanobody fusion protein (vGFP) as a scaffold yielded a construct with a melting temperature of 80°C. This was further increased to 85°C when a thermostable PETase variant (FAST PETase) was scaffolded into vGFP, the highest reported so far for an engineered PET hydrolase derived from IsPETase. Thermostability enhancement using the vGFP scaffold did not compromise activity on PET compared to IsPETase. These contrasting results highlight potential topological and dynamic constraints imposed by scaffold choice as determinants of enzyme activity.     

Comparing the binding properties of peptides mimicking the Envelope protein of SARS‐CoV and SARS‐CoV‐2 to the PDZ domain of the tight junction‐associated PALS1 protein

The Envelope protein (E) is one of the four structural proteins encoded by the genome of SARS‐CoV and SARS‐CoV‐2 Coronaviruses. It is an integral membrane protein, highly expressed in the host cell, which is known to have an important role in Coronaviruses maturation, assembly and virulence. The E protein presents a PDZ‐binding motif at its C‐terminus. One of the key interactors of the E protein in the intracellular environment is the PDZ containing protein PALS1. This interaction is known to play a key role in the SARS‐CoV pathology and suspected to affect the integrity of the lung epithelia. In this paper we measured and compared the affinity of peptides mimicking the E protein from SARS‐CoV and SARS‐CoV‐2 for the PDZ domain of PALS1, through equilibrium and kinetic binding experiments. Our results support the hypothesis that the increased virulence of SARS‐CoV‐2 compared to SARS‐CoV may rely on the increased affinity of its Envelope protein for PALS1.     

Biotechnological applications of microbial bioconversions

Modern research has focused on the microbial transformation of a huge variety of organic compounds to obtain compounds of therapeutic and/or industrial interest. Microbial transformation is a useful tool for producing new compounds, as a consequence of the variety of reactions for natural products. This article describes the production of many important compounds by biotransformation. Emphasis is placed on reporting the metabolites that may be of special interest to the pharmaceutical and biotechnological industries, as well as the practical aspects of this work in the field of microbial transformations.     

The Development of the Pediatric NAFLD Fibrosis Score (PNFS) to Predict the Presence of Advanced Fibrosis in Children with Nonalcoholic Fatty Liver Disease

Background

Noninvasive hepatic fibrosis scores that predict the presence of advanced fibrosis have been developed and validated in adult patients with NAFLD. The aims of our study were to assess the utility of commonly used adult fibrosis scores in pediatric NAFLD and to develop a pediatric specific fibrosis score that can predict advanced fibrosis.

Methods

Consecutive children with biopsy-proven NAFLD were included. Fibrosis was determined by an experienced pathologist (F0–4). Advanced fibrosis was defined as fibrosis stage ≥3. The following adult fibrosis scores were calculated for each child: AST/ALT ratio, AST/platelet ratio index (APRI), NAFLD fibrosis score (NFS), and FIB-4 Index. Multivariable logistic regression analysis was performed to build a new pediatric model for predicting advanced fibrosis.

Results

Our cohort consisted of 242 children with a mean age of 12.4±3.1 years and 63% were female. 36 (15%) subjects had advanced fibrosis. APRI and FIB-4 were higher in patients with advanced fibrosis compared to those with fibrosis stage 0–2; however, AST/ALT ratio and NFS were not different between the two groups. We used our data to develop a new model to predict advanced fibrosis which included: ALT, alkaline phosphatase, platelet counts and GGT. The multivariable logistic regression model (z) was defined as follows: z = 1.1+(0.34*sqrt(ALT))+(0.002*alkaline phosphatase) – (1.1*log(platelets) – (0.02*GGT). This value was then converted into a probability distribution (p) with a value between 0 to 100 by the following formula: p = 100×exp(z)/[1+exp(z)]. The AUCROC for this model was 0.74 (95% CI: 0.66, 0.82). This was found to be significantly better than APRI, NAFLD Fibrosis Score and FIB-4 Index.

Conclusion

Noninvasive hepatic fibrosis scores developed in adults had poor performance in diagnosing advanced fibrosis in children with NAFLD. We developed a new pediatric NAFLD fibrosis score with improved performance characteristics.