Concentrations Of Galactose Research Articles

Isabgol (Plantago ovata) and lentil (Lens culinaris) intercrop responses to arbuscular mycorrhizal fungi inoculation

ABSTRACT Intercropping medicinal plants with grain legumes provides an excellent opportunity for small-scale farmers to generate more income and move towards sustainable cropping systems. The effect of arbuscular mycorrhizal fungi (AMF) inoculation on yield, quality and nutrient uptake of isabgol and lentil, when grown as monocrops or in various intercropping ratios, were evaluated. Inoculation with AMF resulted in positive effects on AMF root colonisation, yield components and seed yields (significant for lentils only) of both crops, especially in the intercropping systems, as well as in the nutrient uptake in isabgol. The highest seed yields of isabgol (743 kg ha−1) and lentil (684 kg ha−1) were obtained when these species were grown as monocrops and inoculated with AMF. The highest mucilage content (20.9%) and swelling factor (16.9 ml) of the isabgol seeds were found when the two secies were grown in the intercropping ratio of 2I:2L (2 rows isabgol: 2 rows lentil) and treated with AMF. Regarding the composition of the isabgol seed mucilage, the highest concentrations of galacturonic acid (9.0%), galactose (11.8%), glucuronic acid (18.3%), and xylose (39.0%) were recorded in intercropping with AMF treatment. AMF inoculation also increased soil basic microbial respiration, soil substrate-induced respiration and soil microbial biomass carbon. Overall, the highest land equivalent ratio (LER = 1.67) was recorded in the 4I:2L intercropping pattern with AMF inoculation. The results indicated that intercropping of isabgol and lentil together with AMF inoculation was an effective system to increase the use efficiency of resources for smallholder farmers in semi-arid regions.

Stabilization of β-Galactosidase on Modified Gold Nanoparticles: A Preliminary Biochemical Study to Obtain Lactose-Free Dairy Products for Lactose-Intolerant Individuals.

The unique chemical, optical, and electrical characteristics of nanoparticles make their utilization highly successful in every field of biological sciences as compared to their bulk counterpart. These properties arise as a result of their miniature size, which provides them an excellent surface area-to-volume ratio, inner structure, and shape, and hence increases their surface characteristics. Therefore, this study was undertaken to engineer gold nanoparticles (AuNPs) for improving their catalytic activity and stability in biotechnological processes. The characterization of AuNPs was performed by XRD, UV spectra, and TEM. The synthesized AuNPs were surface-modified by polyvinyl alcohol (PVA) for binding the enzyme in excellent yield. The developed immobilized enzyme system (PVA-AuNPs-β-galactosidase) displayed pH optima at pH 7.0 and temperature optima at 40 °C. Moreover, the stability of PVA-AuNPs-β-galactosidase was significantly enhanced at wider pH and temperature ranges and at higher galactose concentrations, in contrast to the free enzyme. β-galactosidase bound to PVA-modified AuNPs exhibited greater operational activity, even after its sixth reuse. The developed nanosystem may prove useful in producing lactose-free dairy products for lactose-intolerant patients.

A Comparative Study of Maize and Miscanthus Regarding Cell-Wall Composition and Stem Anatomy for Conversion into Bioethanol and Polymer Composites

Due to an increasing demand for environmentally sustainable products, miscanthus and maize stover represent interesting lignocellulosic resources for conversion into biofuels and biomaterials. The overall purpose was to compare miscanthus and maize regarding cell-wall composition and stem anatomy for conversion into bioethanol and polymer composites using partial least squares regressions. For each of the two crops, six contrasted genotypes were cultivated in complete block design, and harvested. Internodes below the main cob for maize, and on the first aboveground internode for miscanthus, were analyzed for biochemistry and anatomy. Their digestibility was predicted using crop-specific near infrared calibrations, and the mechanical properties were evaluated in stem-based composites. On average, the internode cross-section of miscanthus anatomy was characterized by a thick rind (26.2%) and few but dense pith-bundles (3.5 nb/mm2), while cell-wall constituted 95.2% of the dry matter with high lignin (243.2 mg/g) and cellulose concentrations (439.7 mg/g). Maize internode-anatomy showed large cross-sections (397.5 mm2), pith with the presence of numerous bundles and non-lignified-pith fractions (22.3% of the section). Its cell-wall biochemistry displayed high concentrations of hemicelluloses, galactose, arabinose, xylose, and ferulic acid. Cell-wall, lignin, and cellulose concentrations were positively correlated with rind-fraction and pith-bundle-density, which explained strong mechanical properties as shown in miscanthus. Hemicelluloses, galactose, arabinose, and ferulic acid concentrations were positively correlated with pith fraction and stem cross-section, revealing high digestibility as shown in maize. This underlines interesting traits for further comparative genetic studies, as maize represents a good model for digestibility and miscanthus for composites.

Supplementation of enzyme cocktail in chickens diet is an effective approach to increase the utilization of nutrient in wheat-based diets.

This experiment was conducted to evaluate the effect of supplementing enzyme cocktail on growth performance, digestibility of nutrients, and monosaccharide concentration in ileum and ceca of broiler chickens fed wheat-based diets. A total of 600 male broilers (42.26 ± 1.76 g, 0 day old) were used for 35 days of feeding trial consisting of 2 phases (starter phase from d 0 to 21 and finisher phase from d 21 to 35). Four dietary treatments were prepared based on wheat diets containing four levels of enzyme cocktail supplementation at 0, 0.2, 0.3, and 20 g/kg. Overall, dietary enzyme cocktail supplementation decreased feed conversion ratio (linear p = 0.007; quadratic p = 0.013) and improved (linear p < 0.05) the apparent ileal digestibility of dry matter (DM), crude protein, and soluble and insoluble non-starch polysaccharides. The apparent total tract digestibility of DM and gross energy were increased (linear p < 0.01) with increasing supplementation levels of the dietary enzyme cocktail. The concentrations of arabinose, xylose, mannose, and glucose in ileal digesta were linearly increased (p < 0.01) with increasing enzyme cocktail supplementation levels. In addition, the quadratic effect was observed (quadratic p = 0.046) in mannose concentration of ileal digesta. The concentration of arabinose, xylose, mannose, and galactose in cecal digesta was increased (linear p < 0.05) with increasing dietary enzyme cocktail supplementation levels. The supplementation of enzyme cocktail efficiently increased the utilization of nutrients in broiler and there was no adverse effects of high dosage supplementation level.

Simultaneous Presence of Bacteriochlorophyll and Xanthorhodopsin Genes in a Freshwater Bacterium.

Photoheterotrophic bacteria represent an important part of aquatic microbial communities. There exist two fundamentally different light-harvesting systems: bacteriochlorophyll-containing reaction centers or rhodopsins. Here, we report a photoheterotrophic Sphingomonas strain isolated from an oligotrophic lake, which contains complete sets of genes for both rhodopsin-based and bacteriochlorophyll-based phototrophy. Interestingly, the identified genes were not expressed when cultured in liquid organic media. Using reverse transcription quantitative PCR (RT-qPCR), RNA sequencing, and bacteriochlorophyll a quantification, we document that bacteriochlorophyll synthesis was repressed by high concentrations of glucose or galactose in the medium. Coactivation of photosynthesis genes together with genes for TonB-dependent transporters suggests the utilization of light energy for nutrient import. The photosynthetic units were formed by ring-shaped light-harvesting complex 1 and reaction centers with bacteriochlorophyll a and spirilloxanthin as the main light-harvesting pigments. The identified rhodopsin gene belonged to the xanthorhodopsin family, but it lacks salinixanthin antenna. In contrast to bacteriochlorophyll, the expression of xanthorhodopsin remained minimal under all experimental conditions tested. Since the gene was found in the same operon as a histidine kinase, we propose that it might serve as a light sensor. Our results document that photoheterotrophic Sphingomonas bacteria use the energy of light under carbon-limited conditions, while under carbon-replete conditions, they cover all their metabolic needs through oxidative phosphorylation.IMPORTANCE Phototrophic organisms are key components of many natural environments. There exist two main phototrophic groups: species that collect light energy using various kinds of (bacterio)chlorophylls and species that utilize rhodopsins. Here, we present a freshwater bacterium Sphingomonas sp. strain AAP5 which contains genes for both light-harvesting systems. We show that bacteriochlorophyll-based reaction centers are repressed by light and/or glucose. On the other hand, the rhodopsin gene was not expressed significantly under any of the experimental conditions. This may indicate that rhodopsin in Sphingomonas may have other functions not linked to bioenergetics.

Effects of a blend of mannan and glucan on growth performance, apparent nutrient digestibility, energy status, and whole-blood immune gene expression of beef steers during a 42-d receiving period.

We examined the effects of dietary supplementation of a blend of mannan and glucan on the growth performance, energy status, and whole-blood immune gene expression of newly weaned beef steers during a 42-d receiving period. Forty-eight newly weaned Angus crossbred steers (2-d post-weaning; 199 ± 13 kg of initial body weight [BW]) from a single source were stratified by BW and randomly assigned to one of the two treatments: basal diet with no additive (CON; n = 24) or a basal diet top-dressed with 5 g of a blend of mannan and glucan (MANGLU; n = 24). Average daily gain (ADG) and feed efficiency (FE) from days 1 to 14, 15 to 42, and 1 to 42 were calculated from daily dry matter intake (DMI) and weekly BW. Blood samples were collected on days 0, 14, and 42 for measurement of plasma glucose and nonesterified fatty acids (NEFA). Blood samples collected on days 14 and 42 were composited for each steer for untargeted carbonyl-metabolome analysis (measurement of carbonyl-containing metabolites). Expression of 84 immune-related genes was analyzed on blood samples collected on day 42. Beginning on days 37 to 42, total mixed ration, refusals, and fecal samples were collected once daily to determine apparent total tract digestibility of DM, CP, NDF, and ADF using indigestible NDF as an internal marker. Over the 42-d feeding trial, supplemental MANGLU tended to increase final BW (P = 0.07) and ADG (P = 0.06). Compared to CON, beef steers fed supplemental MANGLU had greater (P = 0.01) DMI during the first 14 d, greater DM digestibility (P = 0.03), and tended to have greater NDF digestibility (P = 0.09). No treatment effects (P > 0.10) on plasma glucose and NEFA on days 14 and 42 were detected; however, carbonyl-metabolome analysis revealed increased (FDR ≤ 0.05) plasma concentrations of galactose and glyceraldehydes, and altered (FDR ≤ 0.05) concentrations of some microbiome-derived metabolites in beef steers fed MANGLU. Compared with CON, MANGLU increased (P ≤ 0.05) the expression of five immune-related genes involved in recognition of and mounting immune defense against microbial pathogens. In conclusion, the results of this study demonstrated that supplemental MANGLU enhances beef cattle immunocompetence and productivity during feedlot receiving period.

Acid hydrolysis conditions for the production of fine chemicals from Gracilaria birdiae alga biomass

Gracilaria birdiae is a tropical agarophytes species of red seaweed that is rich in carbohydrates and presents a great potential for mariculture and economic use. However, it is still understudied as a potential renewable resource. In this study, the hydrolysis conditions of G. birdiae algal biomass, reaction time, and sulfuric acid concentration for obtaining monosaccharides, organic acids, and furanic compounds were optimized. Glucose and galactose concentrations were found to be more affected by algal biomass concentration, while the production of 5-hydroxymethylfurfural (5-HMF) and organic acid were most affected by sulfuric acid concentration. The most suitable conditions to produce glucose (28.56 ± 0.72 g·L−1) and galactose (108.03 ± 1.32 g·L−1) were at 121 °C, with sulfuric acid 1.3 mol·L−1, 841.59 g·L−1 of algal biomass and time of 20 min. For cellobiose (25.39 ± 0.43 g·L−1), the condition was sulfuric acid 0.6 mol·L−1, 680 g·L−1 of biomass, and 10 min. For 5-HMF (19.82 ± 0.43 g·L−1), it was sulfuric acid 0.6 mol·L−1, 680 g·L−1 of biomass and 30 min. Finally, for levulinic (38.88 ± 0.58 g·L−1) and formic acids (26.75 ± 0.54 g·L−1) and, the best conditions were sulfuric acid 2.0 mol·L−1, 680 g·L−1 of biomass and 30 min. Thus being, Gracilaria birdiae is a promising renewable resource to produce fine chemicals and fermentable compounds by optimizing its acid hydrolysis conditions.

Mycoplasma genitalium Biofilms Contain Poly-GlcNAc and Contribute to Antibiotic Resistance.

Mycoplasma genitalium is an important etiologic agent of non-gonococcal urethritis (NGU), known for chronicity and multidrug resistance, in which biofilms may play an integral role. In some bacterial species capable of forming biofilms, extracellular polymeric substances (EPS) composed of poly-N-acetylglucosamine (PNAG) are a crucial component of the matrix. Monosaccharide analysis of M. genitalium strains revealed high abundance of GlcNAc, suggesting a biofilm-specific EPS. Chromatograms also showed high concentrations of galactose and glucose as observed in other mycoplasma species. Fluorescence microscopy of M. genitalium biofilms utilizing fluor-coupled lectins revealed differential staining of biofilm structures. Scanning electron microscopy (SEM) showed increasing maturation over time of bacterial “towers” seen in biofilm development. As seen with Mycoplasma pneumoniae, organisms within fully mature M. genitalium biofilms exhibited loss of cell polarization. Bacteria associated with disrupted biofilms exhibited decreased dose-dependent viability after treatment with antibiotics compared to bacteria with intact biofilms. In addition, growth index analysis demonstrated decreases in metabolism in cultures with disrupted biofilms with antibiotic treatment. Taken together, these data suggest that M. genitalium biofilms are a contributing factor in antibiotic resistance.

Microbial Diversity and Nutritional Properties of Persian "Yellow Curd" (Kashk Zard), a Promising Functional Fermented Food.

“Yellow curd” (YC) is one of the most popular homemade Persian fermented foods and is consumed by many people. Notwithstanding, no studies are available to date on its nutritional and microbiological composition. In this study, we examined YC samples obtained from different local markets of Sistan and Baluchestan province, Iran. The results of the chemical analyses revealed a homogenous content of protein (13.71% ± 1.07), lipids (4.09% ± 0.73), and carbohydrates (61% ± 2.13) among the samples. By comparing the average mineral content of YC with yogurt, many relevant differences were detected. Apart from the calcium content, which was similar on average to that of YC, all other minerals tested are present in higher amounts in YC than in yogurt. The analysis of the main sugars present (i.e., lactose, galactose and glucose) highlighted relevant differences among samples, indicating that different YC samples contain natural strains with different capabilities to metabolize sugars. The concentration of galactose in YC samples should be taken into consideration by galactose intolerant people. From the microbiological perspective, the metagenomics analysis revealed that lactic acid bacteria, and particularly the genera Lactobacillus, Pediococcus, and Streptococcus, were dominant in YC. The information provided shows that YC is an interesting base for the preparation of novel functional foods with a good content of beneficial bacteria.

Relationship between lactose utilization of lactic acid bacteria and browning of cheese during storage.

To produce processed cheese turning hardly brown during transportation and storage at room temperature, natural cheese showing less discoloration should be used as a raw material. The purpose of this study was to clarify the relationship between the lactose utilization of lactic acid bacteria and the browning of cheese during storage. Three type-cultures (Lactobacillus plantarum and Streptococcus thermophilus) and five isolates from Japanese pickles (Lactobacillus spp.) were used. Cheese curds inoculated with these bacteria were prepared and stored. The L. plantarum-inoculated curds showed smaller ΔE-values after storage, an indicator for the browning, compared to the others. Accumulation of galactose was observed in the curd to which S. thermophilus was inoculated. The sample showed larger ΔE-value after storage. These results showed the lactose utilization of bacteria affected galactose concentration in cheese and its browning during storage. L. plantarum might be a good starter for preparing cheese turning hardly brown.

Analyses of Factors Affecting the Browning of Model Processed Cheese during Storage.

The purpose of this study was to clarify factors affecting the browning of a model processed cheese during storage. Model processed cheese samples (pH 4.5-6.0) which were composed of sugars (galactose, glucose, or lactose; 0-1.8%), amino acids (0-2.8%), sodium caseinate (26.0-31.2%), fat from butter (22.0-28.5%), water (44.1%), emulsifying salts (trisodium citrate, disodium tartrate dihydrate, or disodium hydrogen phosphate; 0 or 1.4%), and salt (0-5.0%) were prepared. Each model processed cheese was stored at 50ºC for 4-7 d. The L*-, a*-, and b*-values of model cheese samples before and after storage were measured and the ΔE-value was calculated to estimate the browning. All model cheese samples turned brown during storage. The ΔE-value strongly correlated with the concentration of galactose (r=0.99), and pH (r=0.94), respectively. The galactose-added model cheese turned more intensively brown than glucose or lactose-added ones. The browning was not dependent on the amount of free amino acids, but on the amount of added sodium caseinate. The browning was repressed by the addition of 1 to 3% of NaCl. The model cheese added with disodium hydrogen phosphate as an emulsifying salt turned more intensively brown than those added with disodium tartrate dihydrate or trisodium citrate. The ΔE-values of model cheese samples containing galactose strongly correlated with the decrease in galactose. These results showed that galactose was one of the most important factors for regulating the browning of processed cheese during storage and that the browning was also dependent on pH, protein, NaCl, and an emulsifying salt.

Lactose-Induced Chronic Diarrhea Results From Abnormal Luminal Microbial Fermentation and Disorder of Ion Transport in the Colon.

Diarrhea is one of the major abdominal symptoms in lactose-intolerant subjects. The changes in the large intestinal luminal environment and disorder of the epithelial ion transport in lactose-induced diarrhea remain unclear. The present study aimed to investigate the effect of an incremental high-lactose diet (IHLD, 30%/40%/50%) on luminal microbiota, microbiota-derived metabolite concentrations and colonic ion transport. Gut microbiota were analyzed by 16S rRNA amplicon sequencing and the concentration of SCFAs by gas chromatography, galactose, lactose and lactic acid through assay kit; Ussing chamber was performed to detect basal and stimulated ion transport; The expression and location of SCFA transporters, the Na-H exchanger 3(NHE3), cystic fibrosis transporter regulater (CFTR) and NKCC1 in the colon mucosa were analyzed by western and immunostaining. The concentrations of lactose, galactose and lactic acid of the cecal content were markedly increased (P < 0.01) and SCFA concentration was significantly decreased (P < 0.01). This was associated with depletion of the Lachnospiraceae NK4A136 group and Ruminococcaceae UCG-005 and increased relative abundance of Lactobacillus, escherichia-shigella and megamonas in the cecal microbiota. The expression of monocarboxylate transporter 1 was decreased in the colonic mucosa of the IHLD group. Low NHE3 expression and phosphorylation levels, and decreases in delta basal short circuit current after apical Na+ removal in the colonic mucosa of the IHLD group contributed to Na+ accumulation in the lumen and decrease stimulated Cl– secretion with low CFTR and NKCC1 expression would compensate for water and electrolyte loss during the diarrhea process. These results indicated that the persistence of the diarrhea state was maintained by abnormal colonic microbiota fermentation leading to high concentrations of lactose, galactose and lactic acid and low SCFAs in the lumen, and decreased Na+ absorption with the low NHE3 expression and phosphorylation levels.

Peroxidase-like activity of Fe–N–C single-atom nanozyme based colorimetric detection of galactose

Single atom nanozymes are the artificial enzymes with enzyme-like activity, which have attracted a great deal attention in recent years due to their unique merits such as remarkable stability, excellent atom utilization and low cost. Herein, a convenient and sensitive colorimetric strategy was developed for the sensing of galactose based on Fe–N–C single-atom nanozyme (Fe-SAzyme). The Fe-SAzyme was prepared through “isolation-pyrolysis” method that exhibited intrinsic peroxidase mimicking activity, which can quickly catalyze the oxidation of 3,3′,5,5′-tetramethylbenzidine (TMB) to produce blue-colored oxTMB in the presence of hydrogen peroxide (H2O2). Galactose can be oxidized by galactose oxidase (Gal Ox) to generate H2O2, and Fe-SAzyme can be utilized for quantitative colorimetric detection of galactose. A good linearity between absorbance and the galactose concentration in the range of 50–500 μM was obtained with a detection limit of (LOD) 10 μM. The Fe-SAzyme based colorimetric strategy offered a rapid, convenient and economic way for galactose quantification detection, which could be used as an alternative method for galactosemia diagnosis.

Analysis of the polysaccharide fractions isolated from pea (Pisum sativum L.) at different levels of purification.

Crude pea (Pisum sativum L.) polysaccharides (CPPs) were extracted under ultrasound assistance, and CPP yield was highest to 6.27381%, which optimized using response surface methodology. Enzymatic method was more effective in deproteinization than Trichloroacetic acid and Sevag method, when considering the polysaccharide retention value as well as the protein clearance. Three-phase partitioning deproteinization indicated that the combination of the enzyme and Sevag method was more effective than their single use. Pea polysaccharide fractions were obtained by diethylaminoethyl-52 cellulose (W-DE-PP, N-DE-PP1, and N-DE-PP2) and Sephadex G-100 size-exclusion chromatography (W-DE-GPP, N1-DE-GPPa, and N1-DE-GPPb) in that order. Polysaccharide fractions W-DE-GPP and N1-DE-GPPa were showed a smooth surface with many cavities by Scanning electron microscopy (SEM) in 1,000 folds. All polysaccharides, characterized by high-performance liquid chromatography (HPLC), were composed of rhamnose, arabinose, galactose, glucose, and mannose, with the highest concentrations of galactose and glucose. Compared with different purification levels, N-DE-GPP showed the strongest activity against 2,2-diphenyl-1-picrylhydrazyl and 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and the highest ferric reducing antioxidant power, which were similar to the results of W-DE-GPP. Therefore, W-DE-GPP and N-DE-GPP may be promising natural sources of antioxidants. PRACTICAL APPLICATIONS: Recently, numerous studies on the extraction, purification, characteristics, and bioactivities of polysaccharides have been conducted. We mainly focused on the functional compounds of legumes. Comprehensive studies on pea polysaccharides are limited. Therefore, in the present study, extraction of CPPs was performed to optimize conditions using response surface methodology. Polysaccharide fractions were obtained from different purification levels and were chemically characterized using HPLC and SEM. Antioxidant activities of polysaccharides with different purification levels were determined. All the conventional methods, described in previous studies, were applied in the study. Furthermore, we analyzed and compared the characteristics of polysaccharides at different purification levels. We believe that our results would likely supplement the fundamental studies on pea polysaccharides.

Microwave-Assisted Degradation of Biomass with the Use of Acid Catalysis

The aim of the study was to assess the effectiveness of microwave pretreatment combined with acid catalysis in the decomposition of various types of biomass (pine and beech chips and hemp stems). It was clearly demonstrated that sulfuric acid was a catalyst enabling the most effective decomposition of the tested plant biomass, guaranteeing the highest concentrations of simple sugars released. Acid catalysis with 1% v/v sulfuric acid combined with microwave radiation provided high glucose concentrations of 89.8 ± 3.4, 170.4 ± 2.4 and 164.6 ± 4.6 mg/g for pine chips, beech chips and hemp stems, respectively. In turn, the use of nitric acid promoted the degradation of hemicellulose, which resulted in high concentrations of galactose and xylose, i.e., 147.6 ± 0.6, 163.6 ± 0.4 and 134.9 ± 0.8 mg/g of pine chips, beech chips and hemp stems, respectively, while glucose levels remained relatively low. It was also demonstrated that the undesirable dehydration of sugars such as glucose and xylose is more pronounced in sulfuric acid than nitric acid processes. The use of H2SO4 and increased pressure generated 5-hydroxymethylfurfural (5-HMF) and furfural at a concentration of ca. 12 and 6 mg/g, 10 and 45 mg/g and 14 and 30 mg/g, of pine chips, beech chips and hemp shoots, respectively. Our studies confirmed the usefulness of the combined use of microwaves and acid catalysis in the degradation of softwood, hardwood and non-wood plant biomass. It should be emphasized that obtaining high concentrations of released simple sugars (as potential substrates in biosynthesis), while maintaining low levels of toxic by-products (inhibitors), requires precise selection of process parameters such as pressure, exposition time and type of acid catalyst.

Localized surface plasmon resonance coupled single-particle galactose assay with dark-field optical microscopy

Galactosemia as a metabolic disease is associated with the increase of galactose concentration in blood. Hence, it is important to detect the amount of galactose for the early discovery of diseases. In this study, we demonstrate a convenient and sensitive localized surface plasmon resonance (LSPR) coupled method for the quantification of galactose by single- particle detection (SPD) with dark-field optical microscopy (DFM). The design is based on the specific boronate affinity interaction between the boronic acid ligands and cis-diol groups. The mercaptophenylboronic acid (MPBA) functionalized gold nanoparticles (MPBA-GNPs) served as the signal probe were prepared. In the presence of galactose, MPBA can react with the cis-diol groups of the galactose, resulting in the occurrence of MPBA-GNPs plasmon oscillations coupling and the apparent change of particle scattering color from green to yellow. By quantifying the ratio of yellow particles by SPD with DFM, the trace amount of galactose in solution can be accurately detected. Limit-of-detection (LOD) as low as 0.83 nM is achieved in the linear range of 1–75 nM, which is more sensitive than that of the previous reported ensemble measurement methods. The satisfactory spike recoveries in human urine sample are successfully obtained, which indicates the potential applications of this proposed method in practical sample. As a consequence, this study provides a prospect platform for the ultra-sensitive biomolecules detection in the future.

Reagent-Free Colorimetric Assay for Galactose Using Agarose Gel Entrapping Nanoceria and Galactose Oxidase

A reagent-free colorimetric method for galactose quantification using a composite of cerium oxide nanoparticles (nanoceria) and galactose oxidase (Gal Ox) entrapped in an agarose gel was developed. In the presence of galactose, the Gal Ox entrapped within the agarose gel catalyzed the oxidation of galactose to generate H2O2, which induced a color change from white to intense yellow. This reaction occurred without any chromogenic substrate. This color transition is presumed to be due to the H2O2-mediated alteration of the oxidation state of cerium ions present on the surface of the nanoceria. The intensity of color change was quantified by acquiring an image with a conventional smartphone, converting the image to cyan-magenta-yellow-black (CMYK) mode, and subsequently analyzing the image using the ImageJ software. Using this strategy, galactose concentration was specifically determined with excellent sensitivity of as low as 0.05 mM. The analytical utility of the assay was successfully verified by correctly determining diverse levels of galactose in human serum, which is enough to diagnose galactosemia, a genetic disorder characterized by the malfunctioning of enzymes responsible for galactose metabolism. The assay employing a hydrogel composite with entrapped nanoceria and Gal Ox, is a simple, cost-effective, and rapid colorimetric assay for galactose quantification, without using any chromogenic reagent. This cost-effective method has great potential for the diagnosis of galactosemia and is highly promising in comparison to the laborious instrumentation-based methods currently in use.

Characterization of a protease-resistant α-galactosidase from Aspergillus oryzae YZ1 and its application in hydrolysis of raffinose family oligosaccharides from soymilk

The α-galactosidase gene (galC) was cloned from Aspergillus oryzae YZ1 and expressed in Pichia pastoris. The galC (2319 bp) containing two introns encoded a protein of 726 amino acids. The activity of the α-galactosidase (GalC) increased 1-fold after coding sequence optimization. Purified GalC exhibited a single protein band (100 kDa) in SDS-PAGE. The optimum pH and temperature of GalC were pH 4.66 and 50 °C, respectively. Like many GH36 family α-galactosidases, GalC displayed its activities towards raffinose and stachyose. The Km values for pNPG, raffinose and stachyose were 2.16, 4.63 and 8.54 mM, respectively. The GalC retained about 90% activity within the pH range 3.0–8.0. The activity of GalC was inhibited by Cu2+, while Ca2+ increased the enzyme activity. Different concentrations of glucose, mannose, galactose, xylose and sucrose slightly affected the activity of GalC. The GalC displayed strong resistance to trypsin, α-chymotrypsin, and proteinase K. Under simulated gastric conditions, GalC maintained most of its native activity after pepsin treatment for 3 h. The GalC could also effectively degrade raffinose and stachyose in soymilk. The GalC with high hydrolysis efficiency towards raffinose family oligosaccharides (RFOs) and strong resistance to proteases is considered to have great potential in food and feed industries.

The effect of carbohydrates on nutritional preference and development of Mediterranean flour mouth, Ephestia kuehniella Zeller (Lepidoptera: Pyralidae)

In this study, the effect of different carbohydrates on food consumption, growth and development duration of Ephestia kuehniella Zeller (Lepidoptera:Pyralidae) larvae was investigated. 13 diets containing different carbohydrates were prepared. Control diet did not contain carbohydrates. The 8 diet contains 3% concentration of glucose, galactose, maltose, starch, arabinose, mannose, sucrose or fructose. 2 of the diets contains 10% or 30% starch. 2 of the diets contain a mixture of carbohydrates (2 Glucose: 1Fructose; 2 Fructose: 1 Glucose). According to the results, only the increase in food consumption does not indicate that a carbohydrate is a feeding stimulus. The conversion of carbohydrates is also important. Although the dietary consumption of arabinose is high, pupa dry weight, pupa lipid and pupa protein are not high. Conversely, although the consumption of the glucose-containing diet is low, the pupa dry weight and pupa lipid content are high. The glucose-fructose mixture is stimulant for E. kuehniella larvae. G2-F1 diet is the diet with high food consumption and growth performance. In addition, it was determined that as the starch concentration in the diet increased, the amount of consumption increased but the pupa dry weight, which is an indicator of fecundity, decreased. It is important result that the amount of pupa protein does not differ in diets except carbohydrate free diet and G2-F1 diet.

A photoelectrochemical biosensor based on the direct electron transfer to galactose oxidase

A novel photoelectrochemical biosensor for quantitative detection of galactose was successfully developed by immobilizing galactose oxidase on TiO2 nanorod arrays modified F-doped tin oxide (FTO) electrode. Specifically, the direct electron transfer to galactose oxidase was achieved. TiO2 nanorod arrays directly grew on FTO electrode from peroxotitanium complex precursor under low-temperature and normal-pressure conditions. The large surface area and good uniformity of TiO2 nanorod arrays facilitated direct electron transfer between the electrode surface and galactose oxidase. The photocurrent spectra of as-prepared biosensor showed an obvious photocurrent response under UV light irradiation. The generated photocurrent of the stable platform was significantly enhanced after the addition of galactose in solution and the photocurrent intensity possessed linear relationship with the galactose concentration. Moreover, CaCl2, uric acid and ascorbic acid had no interference with the detection of galactose on the working electrode. This sensor can be reused and measure the concentration of galactose in lactose-free milk.