Maximum Activity Research Articles

Antioxidant and Xanthine oxidase inhibitory activities of the tea (Camellia sinensis) flower

The major purpose of this study was to investigate the DPPH radical scavenging activity, hydroxyl radical scavenging activity, superoxide radical scavenging activity, reducing power, ferrous ion chelating activity, and xanthine oxidase activity for research of antioxidant and xanthine oxidase inhibitory activities using a variety of extracts of tea (Camellia sinensis) flower. Among the several extracts, when 800 μg/mL of the ethanol extract was used, the maximum DPPH radical scavenging activity was obtained, 79.2%, which was approximately 80.8% compared to L-ascorbic acid, the maximum hydroxyl radical scavenging activity, 71.3%, which was approximately 73.2% compared to BHA, and the maximum super oxide radical scavenging activity, 89.4%, which was, approximately 90.6% compared to BHT, and the maximum reducing power, 1.94 at an OD of 700 nm, which was approximately 49.2% compared to L-ascorbic acid, respectively. On the other hand, when 800 μg/mL of the hot water extract was used, the maximum activity of ferrous ion chelate was obtained, 28.6%, which was approximately 48.4% compared to EDTA and the maximum xanthine oxidase inhibitory activity, 61.4%, approximately 63.8% compared to catechin, respectively. These results indicated the application potential for industries that can produce new biomaterials that can compensate for the shortcomings of existing synthetic antioxidants and use discarded tea flower as food, pharmaceutical, and cosmetic materials.

Anti-inflammatory and antioxidant activities of Pleurotus nebrodensis extract : application in a functional tea

This study was designed to examine the nitric oxide production, hyaluronidase, and prostaglandin E2 (PGE2) inhibitory activities for the anti-inflammatory effect and DPPH and ABS radical scavenging activities for antioxidant effect using Pleurotus nebrodensis mycelium extract for a functional tea development. The cell viability was confirmed that all extracts were not cytotoxic to RAW264.7 cell within a concentration of 90 μg/mL irrespective of solvent extracts. The nitric oxide inhibitory activity in LPS-stimulated RAW264.7 cells was the highest at 43.6% using 90 μg/mL of hot water extract. The PGE2 inhibitory level was the highest 32.9% of 90 μg/mL of hot water extract. The hyaluronidase inhibitory activity as the highest 53.5% using 90 μg/mL of hot water extract. On the other hand, in the case of antioxidant activity, the maximum DPPH radical scavenging activity using 90μg/mL of ethanol extract obtained 69.6%. The maximum ABS radical scavenging activity using 90μg/mL of ethanol extract obtained 71.3%. When hot water extract was mixed in green tea, they was considered an excellent extract because the sensory evaluation showed a relatively high value. Based on the results of these experiments, it was possible to confirm the possibility of the functional material development of the tea beverage for anti-inflammatory and antioxidant agents using the hot water and ethanol extract of P. nebrodensis mycelium.

Phytochemical Screening, Antioxidant, Cytotoxic, Analgesic, Antidiarrheal Activity and GC-MS Analysis of the Leaves of Stachyphrynium Placentarium

The goal of the present study is to analyze the phytochemicals, antioxidants, cytotoxic, analgesic and anti-diarrheal properties of the leaves of Stachyphrynium placentarium methanol extract as well as its dichloromethane soluble fraction using GC-MS technique. The leaves of the S. placentarium were extracted with methanol and designated as SPM. Phytochemicals investigation exhibited the presence of several important secondary metabolites. Antioxidants such as total phenolic content, flavonoids content, total antioxidant, reducing power capacity and DPPH (2,2-diphenyl-1-picrylhydrazyl) free radical scavenging assay SPM revealed non-significant antioxidant properties. The cytotoxicity study of the extract showed significant cytotoxicity (LC50 35.1093 µg/mL) compared to standard vincristine sulfate (LC50 0.482 µg/mL). Analgesic study of S. placentarium by hot plate model indicates both the doses exhibited significant central analgesic activity compared with the control. The maximum analgesic activity was observed at 90 min. SPM (500 mg/kg) is 60.21 %. SPM250 also showed a significant percentage of elongation or latency from 30 to 150 min 57.00, 59.64, 59.88, 58.07 and 53.71 %, respectively 30 min time interval. In the acetic acid writhing test, S. placentarium significantly outperformed the control and standard (SPM250 - 52.27 %, SPM500 - 34.09 and STD - 27.27 %), showing a significant increase in peripheral analgesic activity (p < 0.001). Antidiarrheal activity of SPM showed that SPM250 and SPM500 substantially decreased the feces in castor oil-induced diarrhea (p < 0.05). According to the study, the incidence and severity of diarrhea are significantly reduced by SPM500. Four chemicals are found in the dichloromethane-soluble portion of the methanol extract of S. placentarium leaves, according to GC-MS studies such as Octadecane, 6-methyl- (1.326 %), Dodecane (1.02 %), 1-Iodo-2-methylundecane (0.47 %), tetradecanoic acid 12-methyl, methyl ester (72.64 %). Tetradecanoic acid exhibits anti-inflammatory, anticancer, 5-reductase inhibitory, antioxidant, hemolytic and antifibrinolytic properties. HIGHLIGHTS The phytochemicals, antioxidants, cytotoxic, analgesic and anti-diarrheal properties of Stachyphrynium placentarium methanol extract (SPM) leaves. The dichloromethane soluble fraction is examined using Gas chromatography–mass spectrometry (GC-MS) and identified Octadecane, 6-methyl-, Dodecane, 1-Iodo-2-methylundecane, tetradecanoic acid 12-methyl, methyl ester. The brine shrimp lethality test exhibited that SPM has significant cytotoxicity (LC50 35.1093 µg/mL) compared to vincristine sulphate (LC50 0.482µg/mL), the extract showed significant cytotoxicity (LC50 35.1093 µg/mL). S. placentarium at both dosages (250 and 500 mg) provided significant central analgesia compared to the control in a hot plate model. In the acetic acid writhing test, S. placentarium showed significantly higher peripheral analgesic action (SPM250 - 52.27, SPM500 - 34.09 and STD - 27.27 %) compared to control and standard. In castor oil-induced diarrhoea, SPM250 and SPM500 (250 and 500 mg) showed significantly reduced faeces production (p < 0.05). GRAPHICAL ABSTRACT

EFFECT OF ANNEALING DURATION ON PHOTOCATALYTIC PROPERTIES OF LaFeO3 PEROVSKITE

In this paper, the effect of the annealing duration on the photocatalytic properties of lanthanum ferrite perovskite synthesized by the hydrothermal method is investigated. Lanthanum ferrite was chosen as the object of study due to its high activity under the influence of visible light. During the experiments, the structural changes occurring in the material during annealing during 2, 4 and 6 hours were studied. The main attention was paid to the analysis of the morphology of nanoparticles, phase composition, crystallinity, absorption spectra and photocatalytic activity. The results show that an increase in the annealing time leads to an improvement in the crystal structure, an increase in the size of crystallites and a higher level of oxygenation. The optimal annealing time to achieve maximum photocatalytic activity was determined to be 6 hours. The work confirms the prospects of using long-term annealing to improve the photocatalytic properties of perovskite-based materials.

Characterization of a Novel Acid-Stable Chitosanase from Lentinula edodes Suitable for Chitooligosaccharide Preparation

As high-value chitosan derivatives, chitooligosaccharides (COSs) with biodegradable, biocompatible, nontoxic, antimicrobial, and antioxidant activities have been widely applied in food-related fields. Chitosanases can hydrolyze chitosan to produce COSs. Herein, a chitosanase (LeCho1) from Lentinula edodes was successfully expressed in Escherichia coli and was then purified and characterized. LeCho1 had a low sequence identity with other chitosanases reported from the GH75 family. The recombinant protein showed a molecular mass of 27 kDa on SDS-PAGE. LeCho1 preferentially hydrolyzed chitosan with a high degree of deacetylation (DDA) and exhibited maximal activity (71.88 U/mg) towards 95% DDA chitosan at pH 3.0 and 50 °C. It possessed good stability at pH 2.0–6.0 and temperatures below 45 °C. Its hydrolytic activity was remarkably enhanced by the metal ion Mn2+ at 1 mM, while it was totally inhibited by 1 mM Fe3+ or 10 mM EDTA. Its Km and Vmax values were 0.04 μM and 76.81 μmol·min−1·mg−1, respectively, indicating good substrate affinity. LeCho1 degraded chitosan into COSs with degrees of polymerization (DPs) of 2–5, while it had no action on COSs with DPs of less than 5, revealing its endo-chitosanase activity. This study proved that chitosanase LeCho1 is a promising candidate in the industrial preparation of COSs due to its excellent properties.

New Bacillus paralicheniformis strain with high proteolytic and keratinolytic activity.

Bacillus paralicheniformis T7, which exhibits high proteolytic and keratinolytic activities, was isolated from soil in Kazakhstan. Its secreted proteases were thermostable and alkaline, demonstrating maximum activity at 70°C and pH 9.0. The proteases and keratinases of this strain were sensitive to Ni2+, Co2+, Mn2+, and Cd2+, with Cu2+, Co2+ and Cd2+ negatively affecting keratinolytic activity, and Fe3+ ions have a strong inhibitory effect on proteolytic and keratinolytic activity. Seven proteases were identified in the enzymatic extract of B. paralicheniformis T7: four from the serine peptidase family and three from the metallopeptidase family. The proteases hydrolyzed 1mg of casein, hemoglobin, gelatin, ovalbumin, bovine serum albumin, or keratin within 15s to 30min. The high keratinolytic activity of this strain was confirmed through the degradation of chicken feathers, horns, hooves, wool, and cattle hide. Chicken feathers were hydrolyzed in 4 days, and the degrees of hydrolysis for cattle hide, wool, hoof, and horn after 7 days of cultivation were 97.2, 34.5, 29.6, and 3.6%, respectively. During submerged fermentation with feather medium in a laboratory bioreactor, the strain secreted enzymes with 249.20 ± 7.88 U/mL protease activity after 24h. Thus, B. paralicheniformis T7 can be used to produce proteolytic and keratinolytic enzymes for application in processing proteinaceous raw materials and keratinous animal waste.

Synthesis, Characterization and Influence of Copper Nanoparticles on Growth of Vigna mungo L. Hepper CO-7 Variety

The copper nanoparticle was synthesized by employing Cnidoscolus aconitifolius (Mill) leaf extract. The nanoparticles were characterized by UV, FTIR and SEM studies. The SEM image showed a spherical structure. The bio-stimulant effect of green synthesized copper nanoparticles on Vigna mungo L. Hepper was investigated. Seed germination, biochemical, antioxidant, and enzyme activities of the copper nanoparticles were studied. The germination and morphological characteristics were superior at 100 mg/L copper nanoparticle-treated seeds. The biochemical parameters such as chlorophyll (0.701±0.107 mg/g), carbohydrate (4.657±0.090 mg/g), protein (4.396±0.335 mg/g), amino acid (18.557±0.638 mg/g), phenol (10.824±0.53 mg/g), flavonoid (3.644±0.171 mg/g), alkaloid (6.529±0.45 mg/g), and tannin (12.159±0.218 mg/g) were higher at a nanoparticle concentration of 100 mg/L. As far as the enzymatic activities, the maximum activity of nitrate reductase (4.505±0.203 mg/g) and α-amylase (13.195±0.285 mg/g) were observed with 100 mg/L copper nanoparticle-treated seedlings. The in vitro antioxidant activities were also studied.

Cold plasma-induced covalent binding with epigallo-catechin 3-gallate: A strategy for antigenicity reduction and antioxidant improvement of β-lactoglobulin

The application of cold plasma (CP) treatment was investigated for its effectiveness in promoting the covalent grafting of β-lactoglobulin (β-LG) and epigallo-catechin 3 -gallate (EGCG), as well as improving the antioxidant capacity of β-LG and eliminating its antigenicity. The results indicated that CP treatment significantly enhanced the covalent grafting of β-LG and EGCG. The maximum EGCG content in β-LG-EGCG complexes reached 47.08 ± 0.58 mg/g (with 45 s treatment), as confirmed by SDS-PAGE analysis and FTIR spectroscopy. Additionally, LC-MS/MS identifies two binding sites (T76 and K77) of EGCG in the β-LG-EGCG conjugates. After 60 s treatments, there was a significant reduction in the IgG binding capacity of β-LG-EGCG conjugates (29.97 ± 0.05%). Further analysis suggested that the change in the conformational epitopes of β-LG, due to the conjugating with EGCG, was likely the main factor responsible for the reduced binding Immunoglobulin G (IgG) capacity. The maximum antioxidant activities of β-LG-EGCG conjugates were found to be 974.14 ± 1.94 μmol TE g−1 for ABTS and 748.48 ± 9.66 μmol TE g−1 for DPPH). These values represent an eightfold increase in DPPH activity and a twofold increase in ABTS compared to the control sample. This study demonstrated that the CP treatment is highly effective technology for facilitating the covalent grafting of polyphenols to proteins, thereby enhancing their antioxidant properties and eliminate their antigenicity.

In vitro and in vivo pharmacological evaluation of polygonum persicaria l.

The present study was designed to investigate the in vitro antioxidant, cytotoxic, anthelmintic and in vivo analgesic, anti-diarrheal, hypoglycemic and CNS anti-depressant properties of different solvent fractions of methanol extract of leaf and flower of Polygonum persicaria L., a notable medicinal plant in Bangladesh. The crude methanol extracts were partitioned separately to petroleum-ether, carbon tetrachloride, chloroform and aqueous fractions. In DPPH scavenging assay for antioxidant test, the aqueous fraction of flower extract showed maximum antioxidant activity with IC50 of 0.60 μg/ml. Most of the fractions revealed prominent lethality (LC50) against brine shrimp nauplii. The test samples also exhibited dose-dependent anthelmintic activity against Pheretima posthuma. The leaf extract and flower extract (200-and 400 mg/kg b.w.) can decrease the painful sensation in mice. Leaf extracts and flower extracts displayed 57.69 and 50% reduction of diarrhea induced by castor oil in mice, respectively. The plant samples exhibited hypoglycemic effect and CNS anti-depressant effect in mice. Based on the possibility of bioactivity, the plant can be thoroughly examined to determine its potential efficacy and to support its traditional uses. Bangladesh J. Bot. 53(3): 475-485, 2024 (September)

Biochemical characterization of an organic solvent- and salt-tolerant xylanase and its application of arabinoxylan-oligosaccharides production from corn fiber gum

A endo-xylanase, of the glycoside hydrolase family 10 from Schizophyllum commune DB01, was expressed in P. pastoris. Recombinant xylanase (Scxyn5) retained above 80 % maximum activity in 10 % dimethyl sulfoxide and retained 90 % maximum activity in 5 M NaCl on the substrate of birchwood xylan. The effect of NaCl on the catalytic activity of Scxyn5 was significantly different toward various substrates, which was caused by the difference of monosaccharide composition and sturcture of the substrates. Furthermore, when corn fiber gum (CFG) was used as a substrate, the catalytic activity of Scxyn5 increased by 1.3–2.03 times in 1–5 M NaCl. Based on response surface methodology, the highest catalytic activity of Scxyn5 in hydrolyzing CFG were achieved with enzymatic temperature of 50 °C, pH value of 6.0, and 4 M NaCl. These properties of Scxyn5 suit the arabinoxylan-oligosaccharides (AXOs) preparation from CFG and some other potential applications in food industry.

Composite photocatalysts g-C<SUB>3</SUB>N<SUB>4</SUB>/TiO<SUB>2</SUB> for hydrogen production and dye decomposition

The photocatalytic activity of the g-C3N4 /TiO2 composite samples in the processes of dye (methylene blue) decomposition and hydrogen evolution from an aqueous ethanol solution under the action of visible radiation (400 nm) has been studied. A new original method for the synthesis of the g-C3N4 /TiO2 composite by depositing g-C3N4 /TiO2 to TiO2 nanoparticles during sol-gel synthesis is proposed. The synthesized photocatalysts were characterized by X-ray diffraction, low-temperature gas adsorption, X-ray photoelectron spectroscopy, high-resolution transmission microscopy, and diffuse reflectance spectroscopy in the UV and visible regions. The maximum activity in the hydrogen evolution reaction was 1.3 mmol h–1, which exceeds the rate of hydrogen evolution on the unmodified g-C3N4 and TiO2 samples.

Statistical Optimisation of Streptomyces sp. DZ 06 Keratinase Production by Submerged Fermentation of Chicken Feather Meal

This study focused on the isolation of actinobacteria capable of producing extracellular keratinase from keratin-rich residues, which led to the selection of an actinobacterial strain referenced as Streptomyces strain DZ 06 (ES41). The Plackett–Burman screening plan was used for the statistical optimization of the enzymatic production medium, leading to the identification of five key parameters that achieved a maximum activity of 180.1 U/mL. Further refinement using response surface methodology (RSM) with a Box–Behnken design enhanced enzyme production to approximately 458 U/mL. Model validation, based on the statistical predictions, demonstrated that optimal keratinase activity of 489.24 U/mL could be attained with 6.13 g/L of chicken feather meal, a pH of 6.25, incubation at 40.65 °C for 4.11 days, and an inoculum size of 3.98 × 107 spores/mL. The optimized culture conditions yielded a 21.67-fold increase in keratinase compared with the initial non-optimized standard conditions. The results show that this bacterium is an excellent candidate for industrial applications when optimal conditions are used to minimize the overall costs of the enzyme production process.

Carbon dot unravels accumulation of triterpenoid in Evolvulus alsinoides hairy roots culture by stimulating growth, redox reactions and ANN machine learning model prediction of metabolic stress response

Evolvulus alsinoides, a therapeutically valuable shrub can provide consistent supply of secondary metabolites (SM) with pharmaceutical significance. Nonetheless, because of its short life cycle, fresh plant material for research and medicinal diagnostics is severely scarce throughout the year. The effects of exogenous carbon quantum dot (CD) application on metabolic profiles, machine learning (ML) prediction of metabolic stress response, and SM yields in hairy root cultures of E. alsinoides were investigated and quantified. The range of the particle size distribution of the CDs was between 3 and 7 nm. The CDs EPR signal and spin trapping experiments demonstrated the formation of O2-•spin-adducts at (g = 2.0023). Carbon dot treatment increased the levels of hydrogen peroxide and malondialdehyde concentrations as well as increased antioxidant enzyme activity. CD treatments (6 μg mL-1) significantly enhanced the accumulation of squalene and stigmasterol (7 and 5-fold respectively). The multilayer perceptron (MLP) algorithm demonstrated remarkable prediction accuracy (MSE value = 1.99E-03 and R2 = 0.99939) in both the training and testing sets for modelling. Based on the prediction, the maximum oxidative stress index and enzymatic activities were highest in the medium supplemented with 10 μg mL-1 CDs. The outcome of this study indicated that, for the first time, using CD could serve as a novel elicitor for the production of valuable SM. MLP may also be used as a forward-thinking tool to optimize and predict SM with high pharmaceutical significance. This study would be a touchstone for understanding the use of ML and luminescent nanomaterials in the production and commercialization of important SM.

Analysis of chicken LGALSL (galectin-related protein) gene’s proximal promoter and its control by Krüppel-like factors 3 and 7

The Galectin-Related Protein (GRP), encoded by the LGALSL gene, assigned to the protein family of β-galactoside-binding Galectins, has lost carbohydrate-binding abilities. Its chicken homolog (C-GRP) occurs in the bursa of Fabricius’ epithelial and B cells. Our study investigates the unknown regulatory mechanisms controlling its expression by analyzing the promoter region of the chicken (C-)LGALSL gene in chicken cells. We aimed to identify the sequence elements of the C-LGALSL gene promoter responsible for maximum activity and transcription factors (TFs) that can modulate this activity. Using luciferase reporter assays, we investigated deletion variants of the 5′ region (−2480 bp to +26 bp). Through in silico analyses and site-directed mutagenesis, we explored potential transcription factor binding sites, identified crucial transcription factors through transient overexpression and tested its direct binding by ChIP. Our findings highlight that the region from −274 to −75 bp, conserved among bird species, is crucial for promoter regulation. Among other tested factors, only the chicken (ch) Krüppel-like factors, chKLF3 and chKLF7, modulate the promoter’s activity. The TFs chKLF3 acts as a repressor, and chKLF7 as an activator, although direct binding could not be confirmed. In conclusion, chKLF3 and chKLF7 contribute, in contrast to other factors with binding sites in the region from −274 to −75 bp, to C-LGALSL gene promoter regulation with a balanced impact on activity.

Production, Characterization, Kinetics, and Thermodynamics Analysis of Amyloglucosidase from Fungal Consortium.

The current study aimed to produce an amyloglucosidase enzyme from the fungal consortium. The best amylolytic fungal consortia were identified as Alternaria alternata and Aspergillus niger through the 18S rDNA technique. Fermentation kinetics and various nutritional and cultural parameters were analyzed. Maximum production was obtained in M4 media, pH 5.5, 30°C, and 4mL inoculum at 150rpm after 72h of incubation. Along with that, sodium nitrate at 2.5%, maltose, beef extract 1%, zinc sulfate (0.1%), and Tween 80 (0.1%) supported the maximum amyloglucosidase production. Amyloglucosidase was partially purified up to 1.6 purification fold with a specific activity of 1.84 Umg-1 in a stepwise manner by ammonium sulfate purification, dialysis, and ion exchange chromatography. The AMG enzyme also revealed maximum activity at 50°C with 5.0 pH. Upon the kinetic analysis, the specific yield coefficient Yp/x and volumetric rates Qp and Qx were also found to be significant in the above optimized conditions. The Km value 0.33mgmL-1 and Vmax 26.31 U mL-1 were obtained at 1% soluble starch substrate. Thermodynamic parameters for soluble starch hydrolysis were as follows: ΔH = 48.78kJmol-1, (Ea) = - 46.0kJmol-1, and ΔS = - 43.10Jmol-1K-1. This finding indicates the indigenously isolated fungal consortium can be the best candidate for industrial applications.

Nutmeg vs mace: Evaluation of functional, nutritional, antioxidant and antimicrobial traits to employ as a food preservative

Nutmeg and mace from Myristica fragrans Houtt. are renowned for their culinary significance and medicinal properties. This study was designed to analyze the functional properties, proximate and mineral composition of nutmeg and mace, phytochemical estimation, antioxidant and antimicrobial potential of nutmeg and mace essential oils and oleoresins. The study was further elaborated by testing their synergistic interaction with streptomycin and antibiofilm potential of the most effective treatment. Results revealed better functional properties, higher fiber (35.2%) and mineral (K, Mg, P, Ca, Mn, Zn) content in nutmeg than mace. Nutmeg and mace essential oils were isolated by hydrodistillation and their respective oleoresins were prepared by the Soxhlet extraction method. Phytochemical screening showed a greater phenolic content in mace oleoresin (43.85 mg GAE/g of dw) and terpenoid content in mace essential oil (75.4%). Among all the treatments, mace oleoresin revealed best antioxidant potential against mustard oil degradation during its accelerated oxidation at 70 °C when stored for 7–28 days with minimum increase in peroxide, anisidine, thiobarbituric acid and total oxidation values of mustard oil. Mace oleoresin also revealed the maximum antibacterial activity against Staphylococcus aureus, Bacillus spp., Escherichia coli and Yersinia enterocolitica (MIC values; 180–530 μg/ml). It also revealed synergistic interaction with streptomycin against all the test bacteria along with a notable decrease in biofilm formation (50% of MIC.) GC-MS studies of mace oleoresin showed the presence of terpenoids, phenylpropanoids, phenols and fatty acids and their esters. Hence, mace oleoresins may be used as a natural and safe food preservative.

Improved levan production by novel Calidifontibacillus erzurumensis LEV207 using one variable at a time approach.

Levan, an exopolysaccharide, has applications in the medical and food sectors. Under natural conditions, levan is produced at a low concentration by microorganisms. This current study focuses on optimizing levan production by a one-variable-at-a-time approach from a novel marine bacterium, Calidifontibacillus erzurumensis LEV207. The growth and levansucrase production by C. erzurumensis LEV207 were studied to optimize the media components and conditions. Sucrose and yeast extract proved to be a good levansucrase inducer. The pH of 6.0 and temperature of 30°C, along with MgSO4 as salt, increased the enzyme activity. Sucrose and yeast extract at the concentration of 50% and 1%, respectively, produced the maximum enzyme activity of 427.4µmol/mL/min after 48h of incubation. Sevag reagent was used for the purification of levan. The optimization process increased the levan (EPSLEV207) production sevenfold with a final yield of 65.58g/L. To confirm the structure and nature of EPSLEV207, NMR and XRD were performed, and the functional groups present in EPSLEV207 were determined using FTIR. Chemical hydrolysis of levan confirmed fructose as the monomer, making EPSLEV207 a homopolysaccharide. EPSLEV207 exhibited 49% and 22% radical scavenging activity against DPPH and ABTS radicals, respectively, and promoted the growth of probiotic strain. EPSLEV207 showed an 88% water solubility index and 78% water retention capacity. The optimization process has increased the yield of levan, highlighting the potential of C. erzurumensis LEV207 to be a viable option for industrial applications.

Effects of Locus Coeruleus Activation on n-Back Performance and Frontoparietal Activity.

Previous studies have linked working memory capacity to restricted hemodynamic responses within critical nodes of the frontoparietal network. Emerging evidence suggests a potential role of the locus coeruleus (LC) in modulating activation of key regions essential for working memory function. This study investigated this hypothesis by examining changes in BOLD signal within the LC and cortex during a parametrically designed verbal working memory task (n-back). fMRI revealed load-dependent task activation, with maximum activation of presumed LC neurons positively correlating with working memory capacity. Furthermore, increased hemodynamic responses in the superior parietal lobes and dorsolateral pFC corresponded with the magnitude of LC activation near working memory capacity limits. An exploratory functional connectivity analysis suggests improvements in working memory performance rely on negative functional connectivity between the LC and cortical regions not primarily involved in task completion. On the basis of previous evidence, this association may represent inhibitory input from cortical regions, enabling phasic bursts of activity from LC neurons, thereby facilitating enhanced cortical activation. This result may also indicate noradrenergic suppression of cortical regions that are not crucial for task completion, leading to enhanced network efficiency. These findings suggest a mechanism by which the LC may improve verbal working memory performance by facilitating enhanced activation in regions critical for visual working memory capacity and active maintenance, potentially enhancing network efficiency.

PRODUCTION AND CHARACTERIZATION OF CELLULASES FROM ASPERGILLUS NIGER UNDER STATIC FERMENTATION

The ever-increasing uses of cellulase in various industries have made it popular among researchers. Annually, a large amount of fruit wastes go into vain, which is a great source of cellulases. The objective of this study is to use grape wastes as substrate for production of cellulases from Aspergillus niger using static fermentation. CMCase and FPase assays were performed to characterize the cellulases. The cellulases’ CMCase and FPase activities and stabilities were analyzed for optimum temperature and pH. The effect of substrate concentration and kinetic constants Km and Vmax, along with thermodynamic analysis, were determined. The effects of several metals on the activity of the enzyme were observed. The optimal temperatures were found as 40 °C and 50 °C for CMCase and FPase activity, respectively. CMCase activity shows stability at 20 °C-60 °C, FPase shows low thermal stability as its activity starts to decrease after 50 °C. CMCase and FPase both show maximum activity at pH 6, and maintain their stability at pH 6-7. The values of Km and Vmax obtained from Lineweaver and Burk plot for CMCase are 0.648 mM and 12.953 mM/min, and for FPase are 0.975 mM and 41.493 mM/min. The Arrhenius plot was used to calculate activation energy (Ea) as -19 kJ/mol, and enthalpy of reaction (ΔH) as 16.4 kJ/mol, while entropy ΔS -16.4 kJ/mol was obtained from the plot of ln(Vmax/T) versus the inverse of temperature (1/T). Most metals induce enzyme activities, whereas EDTA inhibits enzyme activities. The findings suggest A. niger has remarkable cellulase production potential from grape wastes in static fermentation, at optimum temperature and pH levels for achieving enzyme activity and stability.

Identification of a thermostable L-asparaginase from Pyrococcus yayanosii CH1 and its application in the reduction of acrylamide.

L-asparaginase (ASNase, E.C. 3.5.1.1) catalyzes the deamination of L-asparagine to L-aspartic acid and ammonia and is widely used in medicine to treat acute lymphocytic leukemia. It also has significant applications in the food industry by inhibiting acrylamide formation. In this study, we characterized a thermostable ASNase from the hyper thermophilic strain, Pyrococcus yayanosii CH1. The recombinant enzyme (PyASNase) exhibited maximal activity at pH 8.0 and 85°C. Moreover, PyASNase demonstrated promising thermostability across temperatures ranging from 70 to 95°C. The kinetic parameters of PyASNase for L-asparagine were a Km of 6.3mM, a kcat of 1989s-1, and a kcat/Km of 315.7mM-1s-1. Treating potato samples with 10 U/mL of PyASNase at 85°C for merely 10min reduced the acrylamide content in the final product by 82.5%, demonstrating a high efficiency and significant advantage of PyASNase in acrylamide inhibition.