Engineered β-glycosidase from Hyperthermophilic Sulfolobus solfataricus with Improved Rd-hydrolyzing Activity for Ginsenoside Compound K Production

Hyperthermophilic Sulfolobus solfataricus β-glycosidase (SS-βGly), with higher stability and activity than mesophilic enzymes, has potential for industrial ginsenosides biotransformation. However, its relatively low ginsenoside Rd-hydrolyzing activity limits the production of pharmaceutically active minor ginsenoside compound K (CK). In this study, first, we used molecular docking to predict the key enzyme residues that may hypothetically interact with ginsenoside Rd. Then, based on sequence alignment and alanine scanning mutagenesis approach, key variant sites were identified that might improve the enzyme catalytic efficiency. The enzyme catalytic efficiency (kcat/Km) and substrate affinity (Km) of the N264D variant enzyme for ginsenoside Rd increased by 60% and decreased by 17.9% compared with WT enzyme, respectively, which may be due to a decrease in the binding free energy (∆G) between the variant enzyme and substrate Rd. In addition, Markov state models (MSM) analysis during the whole 1000-ns MD simulations indicated that altering N264 to D made the variant enzyme achieve a more stable SS-βGly conformational state than the wild-type (WT) enzyme and corresponding Rd complex. Under identical conditions, the relative activities and the CK conversion rates of the N264D enzyme were 1.7 and 1.9 folds higher than those of the WT enzyme. This study identified an excellent hyperthermophilic β-glycosidase candidate for industrial biotransformation of ginsenosides.

Genotype-phenotype of autosomal dominant polycystic kidney disease in Malta

BACKGROUND

Autosomal dominant polycystic kidney disease (ADPKD) is characterized by the development of multiple renal cysts causing kidney enlargement and end-stage renal disease (ESRD) in half the patients by 60 years of age. The aim of the study was to determine the genetic aetiology in Maltese patients clinically diagnosed with ADPKD and correlate the clinical features.

METHODS

A total of 60 patients over 18 years of age clinically diagnosed with ADPKD were studied using a customized panel of genes that had sufficient evidence of disease diagnosis using next generation sequencing (NGS). The genes studied were PKD1, PKD2, GANAB, DNAJB11, PKHD1 and DZIP1L. Selected variants were confirmed by bidirectional Sanger sequencing with specifically designed primers. Cases where no clinically significant variant was identified by the customized gene panel were then studied by Whole Exome Sequencing (WES). Microsatellite analysis was performed to determine the origin of an identified recurrent variant in the PKD2 gene. Clinical features were studied for statistical correlation with genetic results.

RESULTS

Genetic diagnosis was reached in 49 (82%) of cases studied. Pathogenic/likely pathogenic variants PKD1 and PKD2 gene were found in 25 and in 23 cases respectively. The relative proportion of genetically diagnosed PKD1:PKD2 cases was 42:38. A pathogenic variant in the GANAB gene was identified in 1 (2%) case. A potentially significant heterozygous likely pathogenic variant was identified in PKHD1 in 1 (2%) case. Potentially significant variants of uncertain significance were seen in 4 (7%) cases of the study cohort. No variants in DNAJB11 and DZIP1L were observed. Whole exome sequencing (WES) added the diagnostic yield by 10% over the gene panel analysis. Overall no clinically significant variant was detected in 6 (10%) cases of the study population by a customized gene panel and WES. One recurrent variant the PKD2 c.709+1G > A was observed in 19 (32%) cases. Microsatellite analysis showed that all variant cases shared the same haplotype indicating that their families may have originated from a common ancestor and confirmed it to be a founder variant in the Maltese population. The rate of decline in eGFR was steeper and progression to ESRD was earlier in cases with PKD1 variants when compared to cases with PKD2 variants. Cases segregating truncating variants in PKD1 showed a significantly earlier onset of ESRD and this was significantly worse in cases with frameshift variants. Overall extrarenal manifestations were commoner in cases segregating truncating variants in PKD1.

CONCLUSIONS

This study helps to show that a customized gene panel is the first-line method of choice for studying patients with ADPKD followed by WES which increased the detection of variants present in the PKD1 pseudogene region. A founder variant in the PKD2 gene was identified in our Maltese cohort with ADPKD. Phenotype of patients with ADPKD is significantly related to the genotype confirming the important role of molecular investigations in the diagnosis and prognosis of polycystic kidney disease. Moreover, the findings also highlight the variability in the clinical phenotype and indicate that other factors including epigenetic and environmental maybe be important determinants in Autosomal Dominant Polycystic Kidney Disease.

A sulfated exopolysaccharide derived from Chlorella sp. exhibiting in vitro anti-α-D-Glucosidase activity

There is a great scientific curiosity to discover all environments sheltering microalgae, especially those with exceptional characteristics from coldest to hottest ones, the purpose remains to explore the potential of the native microalgae flora and the research for new bioactive compounds. This study aimed to isolate a polysaccharide-producing microalga from an extreme ecosystem and to evaluate its capacity to inhibit the α-D-glucosidase enzyme. Chlorella strain is isolated from hypersaline Lake in the Algerian desert. The exopolysaccharide extraction was performed by the concentration of free-cell supernatant in a rotary evaporator. The infrared analysis showed a characteristic footprint of carbohydrates with particular functional groups, such as sulfate. Gas chromatography-mass spectrometry has revealed a hetero-exopolysaccharide composed of galactose 35.75%, glucose 21.13%, xylose 16.81%, fructose 6.96%, arabinose 5.10%, and glucuronic acid 2.68%. The evaluation of the anti-hyperglycemic activity demonstrated a significant α-D-glucosidase inhibition of 80.94 ± 0.01% at 10 mg mL-1 with IC50 equal to 4.31 ± 0.20 mg mL-1. This study opens a vast prospect to use exopolysaccharides as natural nutraceutical or food additive.

Empirical evidence challenges the effectiveness of the enzymatic stoichiometry of glucosidase and phosphatase as an indicator of microbial C vs P limitation

The ratio of β-1,4-glucosidase (BG) to acid/alkaline phosphomonoesterase (AP) (BG:AP) is commonly employed as an indicator to assess the relative microbial limitations of carbon (C) and phosphorus (P), whereby a higher BG:AP ratio suggests stronger C limitations. This approach is based on the assumption that BG and AP can represent enzymes targeting C and P, respectively. Nevertheless, it is crucial to recognize that microbial C and P acquisition involves the participation of other enzymes alongside BG and AP, and thus, the capacity of BG and AP to accurately and comprehensively represent the entire spectrum of C and P acquisition is questionable. Here, analyzing previously published data, I present a piece of empirical evidence that challenges the suitability of the BG:AP ratio as an accurate indicator of microbial limitations concerning C vs P. P fertilization decreased BG:AP in up to 27 % out of the total 109 observations, which represents a clear contradiction, as this outcome is interpreted by the enzymatic stoichiometry approach as indicating an intensified P limitation arising from P fertilization. Furthermore, the effect of P fertilization on the BG:AP ratio did not show significant differences between experimental sites characterized by higher BG:AP ratios (indicative of lesser P limitation) and those with lower BG:AP ratios (indicative of greater P limitation). Consequently, I conclude that the BG:AP ratio inadequately reflects microbial C vs P limitations.

PRKCSH serves as a potential immunological and prognostic biomarker in pan-cancer

Protein kinase C substrate 80K-H (PRKCSH) plays a crucial role in the protein N-terminal glycosylation process, with emerging evidence implicating its involvement in tumorigenesis. To comprehensively assess PRKCSH's significance across cancers, we conducted a pan-cancer analysis using data from The Cancer Genome Atlas (TCGA), Genotype-Tissue Expression (GTEx), and Cancer Cell Line Encyclopedia (CCLE). We assessed aberrant PRKCSH mRNA and protein expression, examined its prognostic implications, and identified correlations with clinical features, tumor mutational burden (TMB), microsatellite instability (MSI), and tumor immunity across cancer types. We explored PRKCSH gene alterations, DNA methylation, and their impact on patient prognosis. Gene Set Enrichment Analysis (GSEA) and single-cell analysis revealed potential biological roles. Additionally, we investigated drug susceptibility and conducted Connectivity Map (Cmap) analysis. Key findings revealed that PRKCSH exhibited overexpression in most tumors, with a significant association with poor overall survival (OS) in six cancer types. Notably, PRKCSH expression demonstrated variations across disease stages, primarily increasing in advanced stages among eleven tumor types. Moreover, PRKCSH exhibited significant correlations with TMB in five cancer categories, MSI in eight, and displayed associations with immune cell populations in pan-cancer analysis. Genetic variations in PRKCSH were identified across 26 tumor types, suggesting favorable disease-free survival. Furthermore, PRKCSH methylation displayed a significant negative correlation with its expression in 27 tumor types, with a marked decrease compared to normal tissues in ten tumors. Cmap predicted 24 potential therapeutic small molecules in over four cancer types. This study highlights that PRKCSH, as a potential oncogene, may be a promising prognostic marker and therapeutic target of immunotherapy for a range of malignancies.

Polyethylene microplastics alter soil microbial community assembly and ecosystem multifunctionality

Although pervasive microplastics (MPs) pollution in terrestrial ecosystems invites increasing global concern, impact of MPs on soil microbial community assembly and ecosystem multifunctionality received relatively little attention. Here, we manipulated a mesocosm experiment to investigate how polyethylene MPs (PE MPs; 0, 1%, and 5%, w/w) influence ecosystem functions including plant production, soil quality, microbial community diversity and assembly, enzyme activities in carbon (C), nitrogen (N) and phosphorus (P) cycling, and multifunctionality in the maize-soil continuum. Results showed that PE MPs exerted negligible effect on plant biomass (dry weight). The treatment of 5% PE MPs caused declines in the availability of soil water, C and P, whereas enhanced soil pH and C storage. The activity of C-cycling enzymes (α/β-1, 4-glucosidase and β-D-cellobiohydrolase) was promoted by 1% PE MPs, while that of β-1, 4-glucosidase was inhibited by 5% PE MPs. The 5% PE MPs reduced the activity of N-cycling enzymes (protease and urease), whereas increased that of the P-cycling enzyme (alkaline phosphatase). The 5% PE MPs shifted soil microbial community composition, and increased the number of specialist species, microbial community stability and networks resistance. Moreover, PE MPs altered microbial community assembly, with 5% treatment decreasing dispersal limitation proportion (from 13.66% to 9.96%). Overall, ecosystem multifunctionality was improved by 1% concentration, while reduced by 5% concentration of PE MPs. The activity of α/β-1, 4-glucosidase, urease and protease, and ammonium-N content were the most important predictors of ecosystem multifunctionality. These results underscore that PE MPs can alter soil microbial community assembly and ecosystem multifunctionality, and thus development and implementation of practicable solutions to control soil MPs pollution become increasingly imperative in sustainable agricultural production.

Biochemical, Toxicological, and in Silico Aspects of Trillium govanianum Wall. ex D.Don (Trilliaceae): A Rich Source of Natural Bioactive Compounds

Trillium govanianum is a high-value medicinal herb, having multifunctional traditional and culinary uses. The present investigation was carried out to evaluate the phytochemical, biological and toxicological parameters of the T. govanianum Wall. ex D. Don (Family: Trilliaceae) roots collected from Azad Kashmir, Pakistan. Phytochemical profiling was achieved by determining total bioactive contents (total phenolic and flavonoid contents) and UHPLC-MS analysis. For biological evaluation, antioxidant activities (DPPH, ABTS, FRAP, CUPRAC, phosphomolybdenum, and metal chelation assays) and enzyme inhibition activities (against AChE, BChE, glucosidase, amylase, and tyrosinase) were performed. Moreover, cytotoxicity was assessed against three human carcinoma cell lines (MDA-MB-231, CaSki, and DU-145). The tested extract was found to contain higher total phenolics (7.56 mg GAE/g dry extract) as compared to flavonoid contents (0.45 mg RE/g dry extract). Likewise, for the antioxidant activity, higher CUPRAC activity was noted with 39.84 mg TE/g dry extract values. In the case of enzyme assays, higher activity was pointed out against the cholinesterase, glucosidase and tyrosinase enzymes. The plant extract displayed significant cytotoxicity against the cell lines examined. Moreover, the in-silico studies highlighted the interaction between the important phytochemicals and tested enzymes. To conclude, the assessed biological activity and the existence of bioactive phytochemicals in the studied plant extract may pave the way for the development of novel pharmaceuticals.

Sweroside: An iridoid glycoside of potential neuroprotective, antidiabetic, and antioxidant activities supported by molecular docking

Oxidative stress can be a series burden on human health and may lead to many chronic diseases such as diabetes and neurological disorders. The use of natural products to scavenge the reactive oxygen species has attracted the attention of many researchers, to safely manage these conditions with fewer side effects, in available and cost-effective ways. The current study aimed at the isolation and structure elucidation of sweroside from Schenkia spicata (Gentianaceae) and the evaluation of its antioxidant, antidiabetic, neuroprotective, and enzyme inhibitory potential via in vitro and in silico studies. The antioxidant potential was evaluated by a variety of assays as ABTS, CUPRAC and FRAP, showing values of 0.34 ± 0.08, 21.14 ± 0.43, and 12.32 ± 0.20 mg TE/g, respectively, while demonstrating 0.75 ± 0.03 mmol TE/g for phosphomolybdenum (PBD) assay. Acetylcholinestrase (AChE), butyrylcholinesterase (BChE) and tyrosinase inhibitory activities were used to evaluate the neuroprotective effect, while the antidiabetic potential was evaluated by measuring α-amylase and glucosidase inhibitory activities. Results revealed that sweroside showed antioxidant and inhibitory effects on the enzymes tested with the exception of AChE. It demonstrated good tyrosinase inhibitory ability with 55.06 ± 1.85 mg Kojic acid equivalent /g. Regarding the antidiabetic ability, the compound displayed both amylase and glucosidase (0.10 ± 0.01 and 1.54 ± 0.01 mmol Acarbose equivalent/g, respectively) inhibitory activities. Molecular docking studies of sweroside on the active sites of the aforementioned enzymes in addition to NADPH oxidase were performed using Discovery Studio 4.1 software. Results revealed good binding affinities of sweroside to these enzymes mainly through hydrogen bonds and van der Waals interactions. Sweroside can be an important antioxidant and enzyme inhibitory supplement, yet further in vivo and clinical studies are required.

Cloning, expression, and molecular modification of glycoside hydrolase family 5 genes from Thermoascus aurantiacus

In this paper, a novel bifunctional cellulase gene cel1 was cloned from Thermoascus aurantiacus by PCR and heterologously expressed in Pichia pastoris GS115. Bioinformatics and other related tools were used to compare the nucleotide homology of target genes, and analyze the signal peptide, transmembrane domain, hydrophilicity, secondary and tertiary structure of proteins. It was concluded that cel1 has similar endoglucanase nucleotide sequences and falls under the GH5 family. It was also found that cel1 has nucleotide sequences similar to glucosidase, which can infer that cel1 may have the properties of glucosidase, indicating that cel1 is multifunctional. At the same time, a part of the nucleotide sequence of the gene was removed to obtain a new gene cel2, and after highly efficient heterologous expression, its specific activity was found to be 2.1 times higher. Its enhancement is related to the exposure of the protein's hollow three-dimensional structure. This paper provides good material for exploring the relationship between the structure of bifunctional enzymes and their functions, which lays a solid foundation for further research and applications, and provides useful insight for gene mining of other novel enzymes.

Antioxidant and Enzyme Inhibitory Activities of Rhoifolin Flavonoid: In Vitro and in Silico Studies

Rhoifolin (apigenin-7-O-β-neohesperidoside) belongs to the class of flavonoids and was reported to exhibit anti-inflammatory, cytotoxic, antidiabetic, hepatoprotective, and cardioprotective activities. The current study presents the in-vitro evaluation of the antioxidative effects of rhoifolin by many assays, namely DPPH, CUPRAC, ABTS, phosphomolybdenum, and FRAP. Enzyme inhibitory potential was also evaluated for acetylcholinesterase (AChE), butyrylcholinesterase (BChE), tyrosinase, amylase, and glucosidase enzymes. While results revealed weak antioxidant activities for rhoifolin, the compound demonstrated some promising enzyme inhibitory effects against BChE (4.03 mg GALAE/g) and tyrosinase (7.44 mg KAE/g) but was not active on AChE. Regarding anti-diabetic enzymes, the compound was active on amylase but did not show any inhibition effect on glucosidase. In-silico molecular docking study was performed for rhoifolin on the active site of NADPH oxidase, BChE, and amylase enzymes to verify the observed enzyme inhibitory effect. Good binding affinities were observed for rhoifolin on all the docked enzymes, revealing numerous hydrogen bonds, carbon-hydrogen, van der Waals interactions. This is the first study to evaluate the enzyme inhibition potential of rhoifolin. We concluded that the increase in the degree of glycosylation might decrease the antioxidant abilities of flavonoids and that rhoifolin had moderate enzyme inhibition abilities to be investigated in future studies.

Evaluation of hypoglycemic and antioxidant effects of Brickellia eupatorioides, Citrus limettioides and Gochnatia hypoleuca

Diabetes is a chronic metabolic condition with a rapidly increasing prevalence. It comes with a rise in the generation of free radicals, potentially leading to additional health issues. Further studies and creative approaches are required to address this. Natural products are potential new antidiabetic drugs that are worth exploring. The aim of the present study is to assess the antihyperglycemic and antioxidant effects of ethanolic extracts of Brickellia eupatorioides, Citrus limettioides and Gochnatia hypoleuca. The antihyperglycemic activity of the extracts was tested on Wistar rats (diabetes induced by alloxan, 150mg/kg), as well as the inhibitory effect on a-glucosidase and a-amylase (in vitro assay). The antioxidant potential was evaluated using DPPH and ABTS assays. The total phenolic and flavonoid contents were also determined. The results indicated that ethanolic extracts of B. eupatorioides induced a powerful hypoglycemic in vivo effect with a significant decrease at 6h after administration, similar to that produced by glibenclamide; the decrease could be related to a-glucosidase inhibition. Moreover, the extract exhibited a potent scavenging activity (IC50 values 33±6mg/mL and 15±2mg/mL in the DPPH and ABTS methods, respectively). The results demonstrated antihyperglycemic and antioxidant activity of ethanolic extracts of B. eupatorioides.

Modeling and evaluation of the sucrose-degrading activity of recombinantly produced oligo-1,6-glucosidase from A. gonensis

Fructose is the most preferred sugar to provide benefits for sweetening and health. As many industrial enzymes are used to produce High Fructose Syrup (HFS), it is vital to explore alternative enzymes for fructose production. Oligo-α-1,6-glucosidase (O-1-6-glucosidase) hydrolyzes non-reducing ends of isomaltooligosaccharides, panose, palatinose, and an a-limit dextrin by breaking α-1,6-glucoside bonds, although it generally has no activity on α-1,4-glucoside bonds of maltooligosaccharides. In this study, sucrose-hydrolyzing activity of O-1-6-glucosidase of thermophilic A. gonensis was evaluated. For this purpose, O-1-6-glucosidase gene region of A. gonensis was cloned in the pET28(a)+ expression vector, the expression product was purified, modeled, and biochemically characterized. The optimal activity of the enzyme was to be at pH 7.0 and 60 °C. The enzyme activity was halved at the end of the 276th h at 60 °C. The enzyme maintained its activity even after 300 h at pH 6.0-10.0. The values of Km, Vmax, kcat, and kcat/Km were determined as 44.69 ± 1.27 mM, 6.28 ± 0.05 µmoL/min/mg protein, 6.70 1/s and 0.15 1/mMs-1, respectively. While Zn2+, Cu2+, Pb2+, Ag2+, Fe3+, Hg2+, and Al2+ metal ions inhibited O-1-6-glucosidase, Mn2+, Fe2+, and Mg2+ ions activated the enzyme. Consequently, A. gonensis O-1-6-glucosidase (rAgoSuc2) has interesting properties, especially for HFS production.

The role of sulfur cycle and enzyme activity in dissimilatory nitrate reduction processes in heterotrophic sediments

The dissimilatory nitrate (NO₃^-) reduction processes (DNRPs) play an important role in regulating the nitrogen (N) balance of aquatic ecosystem. Organic carbon (OC) and sulfur are important factors that influence the DNRPs. In this study, we investigated the effects of sulfur cycle and enzyme activity on DNRPs in the natural and human-modified heterotrophic sediments. Quarterly monitoring of anaerobic ammonium oxidation, denitrification (DNF), and dissimilatory NO₃^- reduction to ammonium (DNRA) in sediments was conducted using ¹⁵N isotope tracing method. qPCR and high-throughput sequencing were applied to characterize the DNF and DNRA microbial abundances and communities. Results showed that instead of the OC, the glucosidase activity (GLU) was the key driver of the DNRPs. Furthermore, instead of the ratio of OC to NO₃^-, the GLU and the ratio of OC to sulfide (C/S) correctly indicated the partitioning of DNRPs in this study. We deduced that the sulfur reduction processes competed with the DNRPs for the available OC. In addition, the inhibitory effect of sulfide (final product of the sulfur reduction processes) on the DNRPs bacterial community were observed, which suggested a general restrictive role of the sulfur cycle in the regulation and partitioning of the DNRPs in heterotrophic sediments.

COVID-19 lockdown-driven changes in the Ganga River ecosystem in response to human perturbations

We examined 10 subsurface water, 5 benthic water and 19 sediment (02 cm) samples along a 518 km of the middle segment of the Ganga River to assess the possible improvements that resulted from the industrial shutdown during the COVID-19 pandemic. The sites included the main stem river, tributary confluences, and two point sources, one of which releases metal-rich effluents and the other flushes municipal sewage. We found significant declines in the carbon, nutrient and metal concentrations in both the water and sediment. Even the most polluted zones did not show hypoxia (dissolve oxygen; DO < 2.0 mg L^-1) that had been observed in the previous year. Despite a significant decline in carbon and nitrogen as substrates, the activities of extracellular enzymes (EEs), such as β-D-glucosidase, FDAase and protease in sediment (0-2 cm depth), increased significantly (p < 0.05) in response to the declining metal concentrations resulting from the industrial shutdown. We found strong negative correlations between EE activity and the concentrations of metal pollutants measured in 2019, but the correlations between these variables appeared poor in 2020 (lockdown period). Also, we found large variances (low stability coefficients) during the period of strong anthropogenic effects (2019). The study indicates that industrial sources are important contributors of metal pollution in the Ganga River and has relevance exploring river ecosystem recovery windows for management decisions.

[Effects of moss biocrusts on soil-microbe-ectoenzyme stoichiometric characteristics in a subtropical area]

The formation and development of biological soil crusts (biocrusts) potentially affect the cycles and stoichiometric characteristics of soil carbon (C), nitrogen (N), and phosphorus (P). However, it is still unclear how soil microbes adapt to such changes. In this study, we examined the effects of moss-dominated biocrusts coverage (0, 1%-20%, 20%-40%, 40%-60%, 60%-80%, and 80%-100%) on soil physicochemical properties, soil microbial biomass, and ectoenzyme activities [β-1, 4-glucosidase (BG), β-1, 4-N-acetyl glucosidase (NAG), acid phosphatase (AP)] in two soil layers (0-5 and 5-10 cm) in the Three Gorges Reservoir area, as well as the covariations of soil-microbe-ectoenzyme C:N:P stoichiometry. The results showed that biocrust development significantly increased soil clay content, water stable aggregates, soil C, N, P contents, and significantly decreased soil bulk density and sand content. Microbial biomass C, N, P and ectoenzyme activities were significantly increased with increasing biocrust coverage. Soil depth did not affect soil physicochemical properties and C:N:P, but significantly affected microbial biomass, ectoenzyme activities, BG:AP and NAG:AP. Soil C, N and P contents were significantly positively correlated with microbial biomass and ectoenzyme activities, negatively correlated with BG:NAG, while positively correlated with NAG:AP, but had no significant correlation with microbial biomass C:N:P. There was no significant correlation between soil-microbe and microbial-ectoenzyme C:N:P. BG:NAG:AP decreased gradually with the increase of C:N:P stoichiometric imbalance between microbe and soil. This study indicated that the microbial metabolism was co-limited by N and P and with stronger P limitation. Microbes could maintain homeostasis by adjusting their own biomass and ectoenzyme C:N:P to adapt to changes in soil ecological stoichiometry driven by biocrust development.

Antioxidant, Antibacterial, and Anti-diabetic Activity of Green Synthesized Copper Nanoparticles of Cocculus hirsutus (Menispermaceae)

The emergence of new technologies has led to the discovery of the biological properties of nanoparticles through green approach. In the present investigation, we report the potential antibacterial, antioxidant, and anti-diabetic properties of copper nanoparticle (CuNPs) synthesized by reducing 3 mM copper acetate solution with aqueous leaf extract of Cocculus hirsutus. A colour change from deep brown to dark greenish brown indicated the formation of copper nanoparticles. The so-formed CuNPs were characterized by employing UV spectroscopy, FTIR, SEM, and EDX analyses which described sheet-like structure morphology having typical size of 63.46 nm. Later, the synthesized CuNPs efficiency was evaluated against bacterial pathogens, and was found highly toxic to B. subtilis and S. aureus strains. The synthesized CuNPs were examined through H₂O₂ and PMA assays which demonstrated the highest free radical scavenging activity. Besides, the resulted CuNPs revealed the higher anti-diabetic efficacy in both the [Formula: see text]-amylase and [Formula: see text] -glucosidase inhibition assays (64.5% ± 0.11 and 68.5% ± 0.11, respectively). Finally, our findings report that C. hirsutus can be exploited as a source for green synthesis of CuNPs, having potent in vitro antioxidant, antibacterial, and anti-diabetic properties.

Inhibition Mechanism of α-Amylase/α-Glucosidase by Silibinin, Its Synergism with Acarbose, and the Effect of Milk Proteins

As a natural flavonolignan, silibinin is reported to possess multiple biological activities, while the inhibitory potential of silibinin on carbohydrate-hydrolyzing enzymes is still unclear. Therefore, in this study, the inhibitory effect and underlying mechanism of silibinin against α-amylase/α-glucosidase were investigated. The results indicated that silibinin showed a strong inhibitory efficiency against α-amylase/α-glucosidase in noncompetitive manners and exhibited synergistic inhibition against α-glucosidase with acarbose. However, interestingly, the inhibitory effect of silibinin was significantly hindered in various milk protein-rich environments, but this phenomenon disappeared after simulated gastrointestinal digestion of milk proteins in vitro. Furthermore, silibinin could combine with the inactive site of α-amylase/α-glucosidase and change the microenvironment and secondary structure of the enzymes, thereby influencing the catalytic efficiency of enzymes. This research suggested that silibinin could be used as a novel carbohydrate-hydrolyzing enzyme inhibitor, and milk beverages rich in silibinin had the potential for further application in antidiabetic dietary or medicine.

Glucose tolerant and glucose stimulated β-glucosidases - A review

The β-glucosidases (β-D-glucoside glucohydrolase, EC 3.2.1.21) hydrolyze glycosidic bonds of alkyl-, amino-, or aryl-β-D-glucosides, cyanogenic glucosides, disaccharides and short oligosaccharides and can also catalyze the synthesis of glycosyl-bonds between different molecules via transglycosylation. Due to their ubiquitous phylogenetic distribution, substrate diversity and ability to both hydrolyze and synthesize glycosidic bonds, the catalysis and regulation of β-glucosidases have been extensively studied. Many β-glucosidases are inhibited by the reaction product glucose, and reduced catalytic activity may limit the biotechnological and industrial applications of these enzymes and this has stimulated the search for β-glucosidases that maintain their activity at high glucose concentrations. Studies of many glucose tolerant enzymes have been reported and due to the ongoing interest in these enzymes, here it has been reviewed this accumulated body of knowledge which provides valuable insights as to the kinetics, structure, regulation and evolution of glucose tolerant and glucose stimulated β-glucosidases.

Elevated 80K-H Protein in Breast Cancer: A Role for FGF-1 Stimulation of 80K-H

An increase in fibroblast growth factor-1 (FGF-1) is established as part of the cause of several important cancers including breast cancer, but the mechanisms by which it induces malignant behavior are not known. We now report that the protein 80K-H, a substrate for PKC, appears to be part of this mechanism and that it is increased in breast cancer and localizes to the nucleus as part of the mechanism. Our conclusion is based on an examination of a total of 58 biopsy specimens from human breast cancer patients for the presence of relationships between the 80K-H protein and the following: fibroblast growth factor receptor-1 (FGFR-1), tumor grade, microvessel counts (MVC), estrogen receptor (ER) and progesterone receptor (PgR) status. Based on histological grading and immunohistochemical (IHC) assays, we found strong direct relationships between 80K-H and FGFR-1 (r=0.49, p=0.003) and tumor grade (r=0.42, p=0.006). A trend for a direct relationship was observed with PgR (r=0.27, p=0.087). Notably, 80K-H immunostaining was largely limited to the epithelial cells of the mammary ducts.

Subsequently, we studied the effects of FGF-1 on 80K-H in cultured human mammary carcinoma epithelial cells in order to establish a more direct relationship between these two molecules. We observed that FGF-1 treatment of MCF-7 cells stimulated translocation of 80K-H protein to the cell nucleus, as demonstrated by subcellular fractionation studies. Maximal intranuclear 80K-H was observed approximately 30 minutes following FGF-1 treatment. In addition, FGF-1 treatment of MCF-7 cells increased growth and invasion of MCF-7 cells, as demonstrated by cell proliferation and a modified Boyden chamber assay, respectively. Further support for 80K-H nuclearization was provided by the immunostaining of human breast cancer specimens and computer-assisted identification of a putative nuclear localization signal (NLS) near the amino terminus of 80K-H protein structure.

These data support the existence of a previously unrecognized FGF-1/80K-H nuclear pathway in progression of human breast cancer and suggest that 80K-H may be useful for the assessment of breast tumor progression.

THE HISTOCHEMICAL DEMONSTRATION OF α-d-GLUCOSIDASE IN MAMMALIAN TISSUES

A histochemical method for the demonstration of α-d-glucosidase is presented. The procedure and the problems encountered in its development are discussed. Surveys of mammalian tissues showed that this enzyme is generally demonstrable by this method only in the mucosa of the duodenum and upper jejunum and in the kidney cortex. Starvation resulted in decreased enzymatic activity in the intestinal mucosa, whereas increased activity was observed after the ingestion of food.

Extensive mutational analysis of PRKCSH and SEC63 broadens the spectrum of polycystic liver disease

Autosomal dominant polycystic liver disease (PCLD) is characterized by progressive development of multiple (> 20) liver cysts. Two separate genes, PRKCSH and SEC63, have been identified to cause familial PCLD. We designed this study with two goals: to assess the relative contribution of PRKCSH and SEC63 mutations in a cohort of unrelated patients with a variable number of liver cysts, and to assess the effect of these mutations on the severity of the PCLD phenotype. We selected patients with two or more liver cysts on radiological studies and excluded those with renal cysts. A total of 51 patients entered the study and three groups were distinguished: A, 2-10 cysts (18 patients); B, 11-20 cysts (nine patients); and C, more than 20 cysts (24 patients). In total we found that eight patients with multiple liver cysts (16%) had PRKCSH (5) or SEC63 (3) mutations. Two patients (11%) from group A had missense mutations (1 PRKCSH and 1 SEC63). Six patients (25%) with more than 20 liver cysts had mutations (4 PRKCSH and 2 SEC63), of which five mutations were chain-terminating. In conclusion, both PRKCSH and SEC63 mutations are associated with polycystic liver disease. Frequency and severity of mutations is higher among patients with more than 20 liver cysts, but also patients with as few as eight liver cysts can be mutation carriers.

Regulation of TRPV5 and TRPV6 by associated proteins

The epithelial Ca2+ channels TRPV5 and TRPV6 are the most Ca2+-selective members of the TRP channel superfamily. These channels are the prime target for hormonal control of the active Ca2+ flux from the urine space or intestinal lumen to the blood compartment. Insight into their regulation is, therefore, pivotal in our understanding of the (patho)physiology of Ca2+ homeostasis. The recent elucidation of TRPV5/6-associated proteins has provided new insight into the molecular mechanisms underlying the regulation of these channels. In this review, we describe the various means of TRPV5/6 regulation, the role of channel-associated proteins herein, and the relationship between both processes.