Impaired gastric accommodation in patients with postprandial distress syndrome type of functional dyspepsia assessed by 2D ultrasonography.

BACKGROUND AND PURPOSE: The pathophysiology of postprandial distress syndrome includes impaired gastric accommodation, hypersensitivity to gastric distension and delayed gastric emptying. 2D-ultrasonography is one of the methods to assess gastric accommodation by measuring proximal gastric area and we evaluated its role in calculating proximal gastric area and thus assessing gastric accommodation in Indian patients with postprandial distress syndrome. METHODS: In a hospital-based comparative analysis, proximal gastric area was measured with 2D-ultrasonography of postprandial distress syndrome (PDS) patients and compared with healthy controls. Five readings were measured every five minutes till 25 minutes after 400 mL of vegetable soup. The Patient Assessment of Upper Gastrointestinal Disorders-Quality of Life (PAGI-QOL score) and diets aggravating PDS symptoms were studied through detailed questionnaires. Sample size was calculated at 80% study power and alpha error of 0.05 to be 30 subjects in each group. RESULTS: The mean age of patients (18 males) vs. 30 healthy controls (25 males) was 40.8 ± 11.50 years vs. 36.37 ± 7.58, respectively, (p = 0.084). Proximal gastric area was significantly lower in patients versus healthy controls at five minutes (22.54 ± 2.77 vs. 30.66 ± 2.55 cm2), 10 minutes (23.03 ± 2.45 vs. 31.10 ± 2.06 cm2), 15 minutes (23.06 ± 2.27 vs. 30.31 ± 2.11 cm2), 20 minutes (22.21 ± 2.31 vs. 29.73 ± 1.71 cm2) and 25 minutes (22.02 ± 2.33 vs. 28.39 ± 1.55 cm2); p < 0.001 at all intervals of time, indicating impaired gastric accommodation. The QOL was poor in all patients with PDS with mean PAGI-QOL score of 31.30 ± 15.05, median of 30, minimum score of 12 and maximum score of 66. CONCLUSIONS: Measurement of proximal gastric area with 2D-ultrasonography is simple and non-invasive. Proximal gastric area in patients was lower than controls, indicating impaired gastric accommodation. Poor quality of life was universal in patients with postprandial distress syndrome.

Characterization of AZ31/HA Biodegradable Metal Matrix Composites Manufactured by Rapid Microwave Sintering.

This study reports the development of magnesium alloy/hydroxyapatite-based biodegradable metal matrix composites (BMMCs) through rapid microwave sintering. Magnesium alloy (AZ31) and hydroxyapatite powder were used in four compositions 0, 10, 15 and 20% by weight. Developed BMMCs were characterized to evaluate physical, microstructural, mechanical and biodegradation characteristics. XRD results show Mg and HA as major phases and MgO as a minor phase. SEM results correlate with the XRD findings by identifying the presence of Mg, HA and MgO. The addition of HA powder particles reduced density and increased the microhardness of BMMCs. The compressive strength and Young's modulus increased with increasing HA up to 15 wt.%. AZ31-15HA exhibited the highest corrosion resistance and lowest relative weight loss in the immersion test for 24 h and weight gain after 72 and 168 h due to the deposition of Mg(OH)2 and Ca(OH)2 layers at the sample surface. XRD analysis of the AZ31-15HA sintered sample after an immersion test was carried out and these results revealed the presence of new phases Mg(OH)2 and Ca(OH)2 that could be the reason for enhancing the corrosion resistance. SEM elemental mapping result also confirmed the formation of Mg(OH)2 and Ca(OH)2 at the sample surface, which acted as protective layers and prevented the sample from further corrosion. It showed that the elements were uniformly distributed over the sample surface. In addition, these microwave-sintered BMMCs showed similar properties to the human cortical bone and help bone growth by depositing apatite layers at the surface of the sample. Furthermore, this apatite layer can enhance osteoblast formation due to the porous structure type, which was observed in the BMMCs. Therefore, it is indicative that developed BMMCs can be an artificial biodegradable composite for orthopedic applications.

Microwaves can kill malaria parasites non-thermally.

Malaria, which infected more than 240 million people and killed around six hundred thousand only in 2021, has reclaimed territory after the SARS-CoV-2 pandemic. Together with parasite resistance and a not-yet-optimal vaccine, the need for new approaches has become critical. While earlier, limited, studies have suggested that malaria parasites are affected by electromagnetic energy, the outcomes of this affectation vary and there has not been a study that looks into the mechanism of action behind these responses. In this study, through development and implementation of custom applicators for in vitro experimentation, conditions were generated in which microwave energy (MW) killed more than 90% of the parasites, not by a thermal effect but via a MW energy-induced programmed cell death that does not seem to affect mammalian cell lines. Transmission electron microscopy points to the involvement of the haemozoin-containing food vacuole, which becomes destroyed; while several other experimental approaches demonstrate the involvement of calcium signaling pathways in the resulting effects of exposure to MW. Furthermore, parasites were protected from the effects of MW by calcium channel blockers calmodulin and phosphoinositol. The findings presented here offer a molecular insight into the elusive interactions of oscillating electromagnetic fields with P. falciparum, prove that they are not related to temperature, and present an alternative technology to combat this devastating disease.

Andrographolide Relieves Post-Operative Wound Pain but Affects Local Angiogenesis.

Andrographolide (Andro), the major constituent of Andrographis paniculata Nees (Acanthaceae), is was known to reduces inflammatory reaction. In the current study, the ability of Andro to reduce pain sensation in a rat post-operative wound model was explored. The hind paws of 18 Sprague-Dawley rats (SD) bearing post-operative wounds received the following three treatments: Saline, Andro via direct injection into the paw (Andro-injected) and Tablet containing Andro + poly (lactic-co-glycolic acid) (PLGA) (Andro-tablet). Von Frey tests assessed mechanical allodynia at 1, 3, 5 h and 1-, 2-, 3-, 4-, and 5-days post-operation. Behavioral analyses were performed to measure reaction threshold and reaction frequencies. Immunoreactivity of p-ERK and GluR1 was examined in the dorsal horn of the spinal cord. Histopathological and immunostaining studies were conducted on paw epidermis to observe the gross morphology and angiogenesis. The threshold for inducing allodynia increased and the reaction frequency reduced in the Andro-injected group compared to the saline-group, at 3 h post-surgery and the effect lasted between 3-4 days. The threshold for inducing pain and reaction frequency for the Andro-tablet group did not differ from the saline-treated group. The levels of p-ERK and GluR1 in the dorsal horn were reduced after Andro treatment. No significant difference in wound healing index was observed between saline and Andro-injected groups, but CD-31 staining showed less angiogenesis in the Andro-injected group. Andro significantly reduced mechanical allodynia compared to saline treatment, both in shorter and longer time frames. Furthermore, Andro influenced the expression of p-ERK and GluR1 in the dorsal horn, and the angiogenesis process in the wound healing area.

Nutritional Comparison of Sacha Inchi (Plukenetia volubilis) Residue with Edible Seeds and Nuts in Taiwan: A Chromatographic and Spectroscopic Study.

Sacha inchi is a source of quality commercial oil in Taiwan. Oil extraction results in sacha inchi residue have not been utilized and not much investigated. Different edible seeds and nuts have different levels of nutrients. This study aims (a) to determine the oil, moisture, ash, protein, carbohydrate, type of fatty acid, resveratrol, and type of sugar in edible seeds and nuts, including sacha inchi residue, and (b) to determine the model to predict the five macronutrients using NIR spectroscopy. The samples used were candlenut, peanut, sesame, sunflower, sacha inchi residue, and black bean. Determination was conducted using NIR spectroscopy, NMR spectroscopy, LC-MS/MS, and HPLC-ELSD. NIR spectroscopy prediction results show that candlenut is rich in oil, and sacha inchi residue is rich in minerals, protein, and moisture. The correct prediction model for oil and moisture is principal component regression, while partial least squares are for ash, protein, and carbohydrates. NMR spectroscopy results showed that all samples were rich in polyunsaturated fatty acids. Sacha inchi residue is rich in omega 3. LC-MS/MS results showed that all samples contained resveratrol, and its highest level was found in sesame. HPLC-ELSD results showed eight types of sugars in the samples. High sucrose was found in sacha inchi residue, sunflower, sesame, and candlenut. The results are expected to provide information on nutrient levels in seeds and nuts to consumers and people who deal with nutrition. Also, results are expected to increase the economic value of sacha inchi residue as a source of diversification of food products in Taiwan.

Effect of Microwave and Conventional Modes of Heating on Sintering Behavior, Microstructural Evolution and Mechanical Properties of Al-Cu-Mn Alloys.

In this research, we intended to examine the effect of heating mode on the densification, microstructure, mechanical properties, and corrosion resistance of sintered aluminum alloys. The compacts were sintered in conventional (radiation-heated) and microwave (2.45 GHz, multimode) sintering furnaces followed by aging. Detailed analysis of the final sintered aluminum alloys was done using optical and scanning electron microscopes. The observations revealed that the microwave sintered sample has a relatively finer microstructure compared to its conventionally sintered counterparts. The experimental results also show that microwave sintered alloy has the best mechanical properties over conventionally sintered compacts. Similarly, the microwave sintered samples showed better corrosion resistance than conventionally sintered ones.

Effect of Molybdenum (Mo) Addition on Phase Composition, Microstructure, and Mechanical Properties of Pre-Alloyed Ti6Al4V Using Spark Plasma Sintering Technique.

The effect of molybdenum additions on the phases, microstructures, and mechanical properties of pre-alloyed Ti6Al4V was studied through the spark plasma sintering technique. Ti6Al4V-xMo (where x = 0, 2, 4, 6 wt.% of Mo) alloys were developed, and the sintered compacts were characterized in terms of their phase composition, microstructure, and mechanical properties. The results show that the equiaxed primary alpha and Widmänstatten (alpha + beta) microstructure in pre-alloyed Ti6Al4V is transformed into a duplex and globular model with the increasing content of Mo from 0 to 6%. The changing pattern of the microstructure of the sample strongly influences the properties of the material. The solid solution hardening element such as Mo enhances mechanical properties such as yield strength, ultimate tensile strength, ductility, and hardness compared with the pre-alloyed Ti6Al4V alloy.

Effect of Nano Copper on the Densification of Spark Plasma Sintered W-Cu Composites.

In the present work, nano Cu (0, 5, 10, 15, 20, 25 wt.%) was added to W, and W-Cu composites were fabricated using the spark plasma sintering (S.P.S.) technique. The densification, microstructural evolution, tensile strength, micro-hardness, and electrical conductivity of the W-Cu composite samples were evaluated. It was observed that increasing the copper content resulted in increasing the relative sintered density, with the highest being 82.26% in the W75% + Cu25% composite. The XRD phase analysis indicated that there was no evidence of intermetallic phases. The highest ultimate (tensile) strength, micro-hardness, and electrical conductivity obtained was 415 MPa, 341.44 HV0.1, and 28.2% IACS, respectively, for a sample containing 25 wt.% nano-copper. Fractography of the tensile tested samples revealed a mixed-mode of fracture. As anticipated, increasing the nano-copper content in the samples resulted in increased electrical conductivity.

Effect of Heating Modes on Reactive Sintering of Ca3Co4O9 Ceramics.

The traditional solid-state reaction method was employed to synthesize bulk calcium cobaltite (Ca349/Ca3Co4O9) ceramics via ball milling the precursor mixture. The samples were compacted using conventional sintering (CS) and spark plasma sintering (SPS) at 850, 900, and 950 °C. The X-ray diffraction (XRD) pattern indicates the presence of the Ca349 phase for samples sintered at 850 and 900 °C. In addition, SPS fosters higher densification (81.18%) than conventional sintering (50.76%) at elevated sintering temperatures. The thermo-gravimetric analysis (TGA) and differential thermal analysis (DTA) performed on the precursor mixture reported a weight loss of ~25.23% at a temperature range of 600-820 °C. This current work aims to analyze the electrical properties (Seebeck coefficient (s), electrical resistivity (ρ), and power factor) of sintered samples as a function of temperature (35-500 °C). It demonstrates that the change in sintering temperature (conventional sintering) did not evince any significant change in the Seebeck coefficient (113-142 µV/K). However, it reported a low resistivity of 153-132 µΩ-m and a better power factor (82-146.4 µW/mK2) at 900 °C. On the contrary, the SPS sintered samples recorded a higher Seebeck coefficient of 121-181 µV/K at 900 °C. Correspondingly, the samples sintered at 950 °C delineated a low resistivity of 145-158 µΩ-m and a better power factor (97-152 µW/mK2).

LED Lights Affecting Morphogenesis and Isosteroidal Alkaloid Contents in Fritillaria cirrhosa D. Don-An Important Chinese Medicinal Herb.

Investigations were carried out to study the effects of light-emitting diode (LED) lights on growth and development of isosteroidal alkaloids in embryogenic calli of Fritillaria cirrhosa D. Don, an important traditional Chinese medicine herb. Calli were cultured in glass bottles, each containing 100 mL of Murashige and Skoog's basal medium supplemented with 2% sucrose and 0.4% gellan gum powder, a gelling agent. These bottles were incubated in a specially designed plant growth chamber equipped with eight different LED lights consisting of single or combinations of four different light spectra emitting blue (450 nm), green (525 nm), red (660 nm), and far-red (730 nm) light. After three months of incubation, morphological changes in embryogenic calli were recorded, and LC-MS/MS analysis of cultures was carried out for peimisine, sipeimine, peiminine, and peimine. The highest number of somatic embryos and the maximum fresh weight was recorded in calli incubated under red (9R), infrared (9IR), and a combination of red+blue+infrared (3R3B3IR), respectively, in decreasing order. The highest contents of peimisine, peiminine, and peimine were recorded under red (9R) and infrared (9IR) lights, respectively. Eight LED lights had significant effects on the morphogenesis of embryogenic calli of F. cirrhosa D. Don and contents of isosteroidal alkaloids.

The protective ability and cellular mechanism of Koelreuteria henryi Dummer flower extract against hydrogen peroxide-induced cellular oxidative damage

BACKGROUND: Koelreuteria henryi Dummer is an indigenous plant in Taiwan. The species has been used in traditional folk medicine for the promotion of liver functions and for treating malaria and urethritis. The present study investigated the antioxidant activity of the flower extract of Koelreuteria henryi Dummer. The extraction conditions were optimized by the contents of total phenolic acids and total flavonoids, and antioxidant activity assays. Moreover, an in vitro study for investigating antioxidant activity of K. henryi flower extract was demonstrated by hydrogen peroxide (H2O2)-induced apoptosis. RESULTS: K. henryi flower extracted for 150 min showed high contents of total phenolic acids and total flavonoids. In an in vitro model, L929 cells were pretreated with K. henryi flower extract, and then treated with H2O2 to induce oxidative damage. Results demonstrated that H2O2-induced apoptosis was inhibited by the treatment of 200 µg/ml K. henryi flower extract through the mitochondria-mediated pathway and mitogen-activated protein kinase (MAPK) pathway. The caspase 8/9 activity and expression of p-p38 and pERK were repressed by K. henryi flower extract. In addition, the prevention of H2O2-induced apoptosis by K. henryi flower extract activated the nuclear factor-erythroid 2-related factor (Nrf2) stress response pathway to transcript heme oxygenase 1 (HO-1). Also, K. henryi flower extract prevented H2O2-induced apoptosis through HO-1 production, as evident by the use of HO-1 inhibitor. CONCLUSIONS: The present study demonstrated that K. henryi flower extract could inhibit the H2O2-induced apoptosis in L929 cells through the activation of the Nrf2/HO-1 pathway.

Toxicity evaluation of water extract of tissue-cultured Taraxacum formosanum by acute, subacute administration, and Ames test

BACKGROUND: Taraxacum species (commonly known as dandelion) used as herbal medicine have been reported to exhibit an antiproliferative effect on hepatoma cells and antitumor activity in non-small-cell lung cancer cells. Although several investigations have demonstrated the safety of Taraxacum officinale, the safety of tissue-cultured plants of T. formosanum has not been assessed so far. Therefore, the present study examines the safety of the water extract of the entire plant of tissue cultured T. formosanum based on acute and subacute toxicity tests in rats, as well as the Ames tests. RESULTS: No death or toxicity symptoms were observed in the acute and subacute tests. The results of the acute test revealed that the LD50 (50% of lethal dose) value of the T. formosanum water extract for rats exceeded 5 g/kg bw. No abnormal changes in the body weight, weekly food consumption, organ weight, or hematological, biochemical, and morphological parameters were observed in the subacute toxicity test. Thus, the no observed adverse effect level (NOAEL) of T. formosanum water extract was estimated to be higher than 2.0 g/kg. Finally, the results of the Ames test revealed that T. formosanum water extract was not genotoxic at any tested concentration to any of five Salmonella strains. CONCLUSIONS: The water extract of tissue-cultured T. formosanum was non-toxic to rats in acute and subacute tests and exhibited no genotoxicity to five Salmonella strains.

Denaturant Induced Equilibrium Unfolding and Conformational Transitional Studies of Germinated Fenugreek ß-Amylase Revealed Molten Globule like State at Low pH.

BACKGROUND: ß-Amylase (EC 3.2.1.2) is a maltogenic enzyme, which releases ß-maltose from the non-reducing end of the substrates. The enzyme plays important roles for the production of vaccine, maltiol and maltose rich syrups. Apart from these applications the enzyme protects cells from abiotic as well as oxidative damage. The enzyme is ßwell characterized in ßplants and microbes and crystal structures of ß-amylases ßhave been ßobtained from sweet potato, soybean and Bacillus cereus. OBJECTIVE: Find out correlation between structural and functional stability induced by change in pH, temperature and chaotropes. METHODS: Activity, intrinsic fluorescence, extrinsic fluorescence, near- and far- ultraviolet circular dichroism spectroscopic measurements were performed. RESULTS: Peaks about 208 nm and 222 nm obtained by near-ultraviolet circular dichroism correspond to α-helix whereas peak at 215 nm shows presence of ß-sheet. At pH 2.0, absence of tertiary structures, exposed of hydrophobic regions and presence of substantial secondary structures, revealed the existence of molten globule like state. Temperature induced denaturation studies showed that the enzyme was stable up to 75 ºC and the process was found to be irreversible in nature. Chaotropes dependent equilibrium unfolding studies revealed that at low concentration of chaotropes, ellipticity and intrinsic fluorescence ßintensity were ßdecreased ßwhereas ßenzymatic activity remained unchanged, which revealed fenugreek ß-amylase is multi-domains enzyme and catalytic ßdomain ßis more ßstable compare to non-catalytic domain. Moreover, the transition was sigmoidal and non-coincidental. CONCLUSION: Results indicate the probable existence of intermediate states that might perform significant role in physiological process and biotechnological applications.

Tunable thermal quenching properties of Na3Sc2(PO4)3:Eu2+ phosphors tailored by phase transformation details.

Luminescence thermal quenching of phosphors is one of the prominent problems in restricting their application in high-power LED devices. In the current work, tunable luminescence thermal quenching behaviors, including abnormal negative thermal quenching and normal thermal quenching, were demonstrated for Na3Sc2(PO4)3:Eu2+ phosphors tailored by phase transformation details. A series of ionic substitution schemes were employed to synthesize α-, ß- and γ-Na3Sc2(PO4)3:Eu2+ phosphors, which show discrepant phase transformations during heating. The thermal event associated with phase transformation is perceived to be responsible for the observations of abnormal negative thermal quenching performances, in view of the suppression of non-radiative paths by consuming thermal energy during the phenomenon of phase transformation. Our results provide an insight into the relationship between the thermal quenching behaviors and phase transformation details of the Na3Sc2(PO4)3:Eu2+ phosphor and offer a useful clue to exploit high thermal stability phosphors.

In vitro propagation of bulblets and LC-MS/MS analysis of isosteroidal alkaloids in tissue culture derived materials of Chinese medicinal herb Fritillaria cirrhosa D. Don.

BACKGROUND: Fritillaria cirrhosa, an important Chinese medicinal herb, is a Class-III protected and highly exploited species by pharmaceutical industry. Dwindling wild populations of species are unable to meet market demand. Therefore, this study was carried out to develop an in vitro propagation method for bulblet production. Also, the study aimed to carry out LC-MS/MS analysis of tissue culture-derived bulblets and callus for the presence of isosteroidal alkaloids (peimissine, verticine, and verticinone), and compare its quantities with commercially available crude drug samples. RESULTS: In vitro seed germination (91%) of F. cirrhosa was achieved on Murashige and Skoog's basal medium (MSBM) supplemented with 6-benzylaminopurine (1 mg L-1) and α-naphthalene-acetic-acid (0.4 mg L-1). On transfer of germinated seeds from Petri-dishes to glass bottles containing hormone-free MSBM, 37.5% of seedlings developed bulblets after 3 months of incubation. Regeneration and multiplication of bulblets were achieved by culture of transverse sections of bulblets on 1/2 X MSBM. By repeated subcultures at an interval of 2 months, 3072 bulblets weighing 1270 g could be produced at the end of 5th subculture. LC-MS/MS analysis showed a significant presence of peimissine in in vitro bulblets while callus incubated in the dark showed presence of peimissine and verticine. CONCLUSION: The study reports an efficient in vitro propagation method of bulblets production of F. cirrhosa and presence of some isosteroidal alkaloids in tissue culture-derived bulblets and callus. The study could be of immense help in production of F. cirrhosa bulblets and callus under laboratory conditions round the year. Also, these results can be used further to investigate production of isosteroidal alkaloids in bioreactors at commercial scale using liquid and cell suspension cultures. Thus, we not only can reduce our dependence on collections from natural habitats, but also can help in in situ conservation of this important species.

Nanoparticles decorated carbon nanotubes as novel matrix: A comparative study of influences of immobilization on the catalytic properties of Lensculinarisß-galactosidase (Lcß-gal).

In the present study, Multiwalled carbon nanotubes (MWCNT) decorated with two different nanoparticles namely tungsten disulfide (WS2) and tin oxide (SnO2), nanocomposites (NCs) were synthesized via hydrothermal method. Spectroscopic studies showed that both synthesized NCs possess nearly same functional groups but MWCNT-SnO2 NCs are rich in O-functional group. Microscopic studies revealed that both NCs have different morphological microstructure. Lens culinaris ß-galactosidase (Lcß-gal) was immobilized using glutaraldehyde cross-linker resulted in immobilization efficiency of 91.5% and 88% with MWCNT-WS2 and MWCNT-SnO2 NCs, respectively. Remarkable increase in rate of hydrolysis of whey lactose has been observed with both NCs i.e. Lcß-gal immobilized MWCNT-WS2 hydrolyzes the 97% whey lactose in 1.5 h while MWCNT-SnO2 showed maximum 92% of whey hydrolysis in 2 h at optimum conditions. Both nanobiocatalyst could serve as a promising candidates for dairy industries and would offer a potential platform for enzyme based biosensor fabrication.

Immobilization of fenugreek ß-amylase onto functionalized tungsten disulfide nanoparticles using response surface methodology: Its characterization and interaction with maltose and sucrose.

In this communication, fenugreek ß-amylase was immobilized onto functionalized tungsten disulfide nanoparticles through cross-linker glutaraldehyde and successful immobilization was confirmed by SEM, AFM and FTIR spectroscopy. To make the process economical and efficient, optimization of independent variables was carried out using Box-Behnken design of response surface methodology. Approximately similar predicted (85.6%) and experimental (84.2%) immobilization efficiency revealed that the model is suitable for design of space. Optimum temperature was calculated to be 60 °C. After immobilization, an increased Km (2.12 times) and a decreased Vmax (0.58 times), indicated inaccessibility of active site residues to the substrate. The immobilized enzyme retained 77% relative activity after 10 uses whereas 40% residual activity was obtained after 120 days. An increased half-life with concomitantly decreased kinetic rate constant revealed that the immobilized enzyme is more stable at a higher temperature and the process followed first-order kinetics (R2 > 0.93). The limit of detection for maltose and sucrose fluorescence biosensor was found to be 0.052 and 0.096 mM, respectively. Thermodynamic parameters such as changes in Gibbs free energy (ΔG < 0), enthalpy (ΔH > 0) and entropy (ΔS >0) revealed that the process is spontaneous and endothermic, driven by hydrophobic interactions. Thermo-stability data at higher temperature for the immobilized enzyme makes it a suitable candidate for industrial applications in the production of maltose in food and pharmaceutical industries. Furthermore, fluorescence biosensor could be used to detect and quantify maltose and sucrose to maintain the quality of industrial products.

Immobilization of fenugreek ß-amylase onto functionalized graphene quantum dots (GQDs) using Box-Behnken design: Its biochemical, thermodynamic and kinetic studies.

ß-Amylase was immobilized onto GQDs using 3-aminopropyltriethoxysilane and glutaraldehyde. Optimization was carried out by Box-Behnken design and binding was confirmed by SEM, AFM, FTIR and fluorescence microscopy. Predicted optimum immobilization efficiency (88.64%) was very close to actual (87.98%), which confirmed the success of the immobilization process. The immobilized enzyme showed maximum activity at pH 5.0 and 57 °C, whereas Km and Vmax were found to be 6.40 mg/mL and 714.28 µmol/min/mg, respectively. The enzyme retained 75% activity after 12 uses at 30 °C. Increased values of ΔG° ΔH°, half-life and activation energy of the enzyme inactivation (ΔEd) revealed that thermo-stability increases after immobilization and the process followed first-order kinetics (r2 > 0.96). The activation energy of catalysis (ΔEa) and ΔEd for immobilized enzyme were 22.58 and 158.99 ± 1.10 kJ/mol, respectively which revealed that denaturation of the enzyme requires a higher amount of energy rather than catalysis. Thermodynamic and fluorescence spectroscopic studies revealed that the process is non-spontaneous (ΔG > 0) and endothermic (ΔH > 0) and occurred through protein unfolding rather than aggregation (ΔS > 0). Thus increase in thermo-stability of immobilized fenugreek ß-amylase and non-toxic nature of GQDs could be exploited for maltose production in beverage, food and pharmaceutical industries.

Carbon nanotubes molybdenum disulfide 3D nanocomposite as novel nanoscaffolds to immobilize Lens culinaris ß-galactosidase (Lsbgal): Robust stability, reusability, and effective bioconversion of lactose in whey.

Multiwalled carbon nanotubes molybdenum disulfide 3D nanocomposite (MWCNT-MoS2 NC) was successfully synthesized via eco-friendly hydrothermal method. The microstructural characterization of synthesized nanocomposite was carried out using different spectroscopic and microscopic techniques. Nanocomposite was activated using glutaraldehyde chemistry and used as a platform to immobilize Lens culinaris ß-galactosidase (Lsbgal) which resulted in 93% of immobilization efficiency. Attachment of Lsbgal onto nanocomposite was confirmed by AFM, FE-SEM, FTIR, and CLSM. The nanobiocatalyst showed broadening in operational pH and temperature working range. Remarkable increase in thermal stability was observed as compared to soluble enzyme. Nanobiocatalyst showed outstanding increase in storage stability, retained 92% of residual activity over a period of 8 months. This offers good reusability as it retained ∼50% residual activity up to 21 reuses and exhibited higher rate of lactose hydrolysis in whey. MWCNT-MoS2 NC conjugated to biomolecules can serve as a potential platform for fabrication of lactose biosensor.

Biochemical and thermodynamic characterization of de novo synthesized ß-amylase from fenugreek.

ß-Amylase has been de novo synthesized from germinating fenugreek seeds. Enzyme has been isolated and purified from 36 h germinated seeds with 226-fold purification and specific activity of 763 U/mg. Homogeneity of the purified ß-amylase has been confirmed with size-exclusion chromatography, SDS-PAGE and MALDI MS/MS analysis. The isoelectric point, optimum pH and temperature of the enzyme were found to be pH 5.2, 5.7 and 57 °C, respectively. The enzyme was specific for soluble starch with Km and Vmax of 2.4 mg/mL and 833.3 U/mg, respectively. Maltose was found to be competitive inhibitor of the enzyme with inhibition constant (Ki) of 14 mM. However, metallic ions like Ag+ and Hg2+ were found to be non-competitive inhibitors of the enzyme. Thermodynamic parameters like Gibbs free energy (ΔG), enthalpy (ΔH) and entropy (ΔS) changes have further revealed that thermal denaturation of the enzyme has followed first-order with the enzyme unfolding rather an aggregation with the process being irreversible. The activation energy of ß-amylase during thermal activation and denaturation were 27.5 kJ/mol and 145.23 kJ/mol, respectively at R2 > 0.92. Thus, the enzyme was stable even at higher temperature with ability of undergoing catalysis making it commercially exploitable, particularly in food and pharmaceutical industries.