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关键词： Stomach   beta-carotene   Cell wall breakdown   Softening   Mechanical forces   Human gastric simulator  

摘要： The role of biochemical and mechanical disintegration on beta-carotene release from steamed sweet potatoes (SSP) and fried sweet potatoes (FSP) during in vitro gastric digestion was investigated. Results revealed that, in the absence of mechanical forces generated by the stomach, biochemical digestion did not have a great effect on the breakdown of cell walls within the sweet potato food matrix and the release of beta-carotene was similar in both SSP and FSP. Cell wall in the plant-food may act as a physical 'barrier' towards the action of gastric juice and to the release of nutrients into the gastric digesta. However, FSP underwent quicker softening and collapse during in vitro gastric digestion compared to the compact and denser structure of SSP. This may explain the faster cell wall breakdown and subsequent beta-carotene release from FSP cellular matrix than SSP when mechanical forces are applied as in the human gastric simulator (HGS).

关键词： inhibitor   lily bulbs   polyphenol oxidase   substrate specificity   thermal inactivation  

摘要： The biochemical properties and thermal inactivation of polyphenol oxidase (PPO) from three main planted lily cultivars in China, namely,Lilium lancifoliumThunb,Lilium ***, andLilium *** cottonwere evaluated. Data indicate that the PPO from three cultivars showed two optimum pH levels of 4.0 and 6.5-7.0 and temperature of 15 degrees C and exhibited the highest affinity toward 4-methylcatechol. However, this enzyme did not exhibit monophenolase activity. Thiourea andL-cysteine were more effective than other inhibitors. The enzymatic activity ofL. lancifoliumThunb PPO crude extract was higher than that ofL. ***. *** cotton. For thermal inactivation,L. *** cottonPPO showed the best thermal resistance at 65-75 degrees C, andL. lancifoliumThunb showed stability at 45 degrees C. The deactivation of the three types of PPO followed the first-order reaction kinetics, and the activation energy (E-a) was 144.28, 138.00, and 107.12 kJ/mol forL. lancifoliumThunb PPO,L. ***, andL. *** cottonPPO, respectively. Practical applications Liliumis an ornamental and edible plant typically used for food and traditional Chinese medicine. Its flowers are used for decoration, and its underground bulbs are rich in various bioactive substances. Fresh lily bulbs easily turn brown and lose economic value during storage and processing. Polyphenol oxidase (PPO) is a crucial molecule involved in the enzymatic browning of fruit and vegetables. In this study, PPO was extracted from three main planted lily cultivars in China. Namely,Lilium lancifoliumThunb,Lilium ***,Lilium *** cottonand was partially characterized. The results are of considerable importance to further understand the PPO of lily bulbs and provide guidance for the inactivation of enzymes and the processing of lily bulb juice.

关键词： allosteric regulation   neutral position   neutral substitutions   pyruvate kinase  

摘要： Understanding how each residue position contributes to protein function has been a long-standing goal in protein science. Substitution studies have historically focused on conserved protein positions. However, substitutions of nonconserved positions can also modify function. Indeed, we recently identified nonconserved positions that have large substitution effects in human liver pyruvate kinase (hLPYK), including altered allosteric coupling. To facilitate a comparison of which characteristics determine when a nonconserved position does vs does not contribute to function, the goal of the current work was to identify neutral positions in hLPYK. However, existing hLPYK data showed that three features commonly associated with neutral positions-high sequence entropy, high surface exposure, and alanine scanning-lacked the sensitivity needed to guide experimental studies. We used multiple evolutionary patterns identified in a sequence alignment of the PYK family to identify which positions were least patterned, reasoning that these were most likely to be neutral. Nine positions were tested with a total of 117 amino acid substitutions. Although exploring all potential functions is not feasible for any protein, five parameters associated with substrate/effector affinities and allosteric coupling were measured for hLPYK variants. For each position, the aggregate functional outcomes of all variants were used to quantify a "neutrality" score. Three positions showed perfect neutral scores for all five parameters. Furthermore, the nine positions showed larger neutral scores than 17 positions located near allosteric binding sites. Thus, our strategy successfully enriched the dataset for positions with neutral and modest substitutions.

关键词： Alpha-glucosidase   Antimicrobial activity   Capsaicin   Carotenoid   Pepper seed oil   Phenolics  

摘要： In this study, the physicochemical, functional, and antimicrobial properties of pepper seed oil (PSO) were determined. PSO was subjected to differential scanning calorimeter (DSC), fatty acid composition, carotenoid, capsaicin, and tocopherol analyses. LC-ESI-MS/MS and NMR were used to characterize and quantify phytochemicals. Resveratrol, luteolin, and 4-hydroxycinnamic acid were the principal phenolics in PSO. A high concentration of unsaturated fatty acids (85.3%), especially linoleic acid (73.7%) is present in PSO. Capsaicin, dihydrocapsaicin, alpha-tocopherol, delta-tocopherol, zeaxanthin, and capsanthin were determined in PSO at concentrations of 762.92, 725.73, 62.40, 643.23, 29.51, 16.83 ppm, respectively. PSO displayed inhibitory activity against alpha-glucosidase rather than alpha-amylase. The antimicrobial activity of PSO was tested against Escherichia coli, Staphylococcus aureus subsp. aureus, Aspergillus brasiliensis and Candida albicans. The antimicrobial potential of PSO was expressed as minimum inhibitory concentration (MIC), minimum bactericidal concentration (MBC) and inhibition zone (IZ) diameter. Polyunsaturated fatty acid, capsaicin, carotenoid, tocopherol, resveratrol contents;the antioxidant, alpha-glucosidase inhibitory and antimicrobial activities of PSO indicated its nutritional value and health promoting nature for the well-being of humans.

关键词： Acid phosphatase   Catalase   Glycine max (L.) Merrill   Glycine sofa Sieb. & Zucc.   Multiple forms   Oxidative stress   Peroxidase   Ribonuclease specific activity  

摘要： Agricultural production is becoming increasingly dependent on the environmental factors that alter soil properties, plant productivity, and product quality. Environment pollution caused by heavy metals because of human activities are among the most dangerous pollutants on the biosphere. Here, we have studied the biochemical adaptation of wild and cultivated soybeans to the simulated effects of lead nitrate and lead acetate. Lead in the form of acetate had a relevant toxic effect, as evidenced by a significant increase in the concentration of malonic dialdehyde in the treated samples relative to control samples. Catalase and peroxidase, possibly performing a signaling function, are involved in the adaptation to the toxicity of Pb salts. The studied Pb salts showed a predominant stimulating effect on the specific activity of acid phosphatases in cultivated soybean, while the ribonuclease activity changed in both Glycine species. Moreover, in wild soybean, it was mostly suppressive, except for the first day. We found that the electrophoretic spectra of acid phosphatases of soybean seedlings was highly stabile, while that of ribonucleases varied depending on the salt. On the seventh day of exposure, lead nitrate caused a decrease in the specific activity of the studied hydrolases of seedlings of cultivated and wild soybeans. A change in the number or electrophoretic mobility of multiple forms of enzymes during treatment with Pb salts was revealed, which indicates the adaptation of the plants at the molecular genetic level. These results imply that the observed enzymes can be used as sensitive indicators for predicting the effects of heavy metals on soybean.

关键词： Morphogenesis   Force   Signaling   Actomyosin   Tension   Yap   Taz   Eph   Ephrin   PIEZO   Development  

摘要： Morphogenesis is a physical process that requires the generation of mechanical forces to achieve dynamic changes in cell position, tissue shape, and size as well as biochemical signals to coordinate these events. Mechanical forces are also used by the embryo to transmit detailed information across space and detected by target cells, leading to downstream changes in cellular properties and behaviors. Indeed, forces provide signaling information of complementary quality that can both synergize and diversify the functional outputs of biochemical signaling. Here, we discuss recent findings that reveal how mechanical signaling and biochemical signaling are integrated during morphogenesis and the possible context-specific advantages conferred by the interactions between these signaling mechanisms.

关键词： Antioxidant   Biomarker   Crustacean   Oxidative stress   Pesticide   Toxicity  

摘要： Penconazole is one of the most widely used fungicides all over the world, and since it spreads to large environments, its toxic effects on non-target organisms are of great concern. The toxic effects of penconazole on crayfish (Astacus leptodactylus), which is a bioindicator in freshwater ecosystems and consumed economically, are not known. Therefore, in this study, the purpose was to contribute to the literature on the potential harmful effects of penconazole on a non-target species,Astacus leptodactylus. For this aim, the acute toxicity (96 h) of penconazole was examined. The 96-h LC(50)value of penconazole was detected as 18.7 mg L-1. Four concentrations of penconazole (18.7 mg L-1, 9.35 mg L-1, 4.68 mg L-1, 2.34 mg L-1) were applied to crayfish for 96 h. The results showed that penconazole had destructive effects on esterase mechanisms by inhibiting acetylcholinesterase (AChE) and carboxylesterase (CaE) activities. Significant increases were observed in all antioxidant parameters (superoxide dismutase (SOD), glutathione peroxidase (GPx), glutathione reductase (GR), glutathione S-transferase (GST), reduced glutathione (GSH), malondialdehyde (MDA)) in all doses except the lowest concentration (2.34 mg L-1). All adenosine triphosphatase (ATPase) activities (Na+/K+-ATPase, Mg2+-ATPase, Ca2+-ATPase, total ATPase) had significant dose-related inhibition in both gill and muscle tissues. In summary, our findings show that acute penconazole administration to crayfish causes significant toxic effects on esterase, antioxidative parameters, and metabolic enzymes.

关键词： antioxidant   digestive   growth   histopathology   immunity   rainbow trout   rosemary extract  

摘要： This research was designed to determine the effects of rosemary (Rosmarinus officinalis) extract on growth, blood biochemistry, immunity, antioxidant, digestive enzymes and liver histopathology of rainbow trout. In a 40-day diet experiment, rainbow trout was fed with the experimental diets containing 0.4, 0.7, 1 and 3 g/kg of rosemary. 0.4 and 0.7 g/kg rosemary extracts had no significant effect on all parameters studied (p > .05). The growth performance (SGR and WG) and feed utilization (FCR and FER) of the fish increased with the increase in the rate of rosemary in the feed (p < .001). Additionally, only the final weight levels were significant at the linear level (p < .05). Rosemary's 1 and 3 g/kg doses increased total protein, trypsin, amylase, lipase, superoxide dismutase (SOD), catalase (CAT), lysozyme, total immunoglobulin (IG) and white blood cell (WBC) levels when compared to control group. However, glucose, aspartate aminotransferase (AST), alanine aminotransferase (ALT), total cholesterol and triglyceride levels decreased significantly (p < .001). Moreover, these doses of rosemary caused a significant reduction in steatosis of liver hepatocytes compared to the control group. In conclusion, the present study showed that rosemary may be useful in reducing the stress effects by increasing the growth, antioxidant, digestive enzymes and immunity levels, as well as reducing the rate of steatosis in the liver of rainbow trout.

关键词： Talaromyces cellulolyticus   Glycoside hydrolase family 5-7 beta-mannanase   Mannanolytic system   Family 1 carbohydrate-binding module   Lignocellulosic biomass  

摘要： Talaromyces cellulolyticus is a promising fungus for providing a cellulase preparation suitable for the hydrolysis of lignocellulosic material, although its mannan-degrading activities are insufficient. In the present study, three core mannanolytic enzymes, including glycosyl hydrolase family 5-7 (GH5-7) beta-mannanase (Man5A), GH27 alpha-galactosidase, and GH2 beta-mannosidase, were purified from a culture supernatant of T. cellulolyticus grown with glucomannan, and the corresponding genes were identified based on their genomic sequences. Transcriptional analysis revealed that these genes were specifically induced by glucomannan. Two types of Man5A products, Man5A1 and Man5A2, were found as major proteins in the mannanolytic system. Man5A1 was devoid of a family 1 carbohydrate-binding module (CBM1) at the N-terminus, whereas Man5A2 was devoid of both CBM1 and Ser/Thr-rich linker region. The physicochemical and catalytic properties of both Man5A1 and Man5A2 were identical to those of recombinant Man5A (rMan5A) possessing CBM1, except for the cellulose-binding ability. Man5A CBM1 had little effect on mannan hydrolysis of pretreated Hinoki cypress. The results suggest that an improvement in Man5A CBM1 along with the augmentation of identified mannanolytic enzyme components would aid in efficient hydrolysis of softwood using T. cellulolyticus cellulase preparation.