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关键词： Catalytic efficiency   Chitin-binding domain endochitinase   FITC-chitin   Heterologous expression   Plant defense  

摘要： DrChit is class I chitinase involved in the digestion of insect prey of Drosera rotundifolia plants. Herein, we cloned the DrChit(-S) open reading frame lacking the 5'- sequence coding signal peptide into the pET32a vector and its derivate lacking the thioredoxin tag. After DrChit(-S) Trx and DrChirs-Trx overexpression in Escherichia coli cells and purification on Ni-NTA agarose, both enzymes exhibited maximum activity at pH 6.0 and 38 degrees C. Surprisingly, the DrChit(-S) + Trx exerted double enzyme activity and improved all kinetic parameters for FITC-chitin substrate degradation resulting in catalytic efficiency three times higher (46.2 mM(-1). s(-1)) than DrChit(-S) + Trx (13.63 mM(-1). s(-1)). The 3D-structure of DrChit(-S) + Inc revealed different spatial arrangement of the three tyrosine residues in chitin-binding site, while their aromatic rings showed better stacking geometry for CH/pi interactions with the carbohydrate substrate. In contrast, there were no significant differences between both enzymes when the effect of metal ions and their antifungal potential were tested. Quantitative in vitro assays showed growth suppression of Fusarium poae (40%), Trichoderma viride (43.8%), and Alternaria solani (52.6%) but not Rhizoctonia solani (sp.). Our study indicates that sundew chitinase has potential in biotechnology either for degradation of chitin to oligomers applicable in medicine or for plant defense fortification. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Biochemical sensor   Microfluidic chip   Fiber-optic sensor   Application  

摘要： An overview of applications of fiber-optic biochemical sensor in microfluidic chips was carried out with a specific focus on different fiber-optic sensors used on chip, detection methods and biochemical application. First, the structure and sensing mechanism of different fiber-optic sensors used on chip was introduced. Second, optical detection methods in microfluidic chips combined with optical fibers and the advantages and disadvantages of each method were introduced and analyzed in detail. Then, applications of fiber-optic biochemical sensors in microfluidic sensor chips in detecting nucleic acids, proteins, cells, chemicals and microfluidic flow rate were classified and introduced, and different fiber-optic biochemical sensors in microfluidic chip were compared. Finally, a prospect of future development of fiber-optic biochemical sensor combined with microfluidic chip was addressed.

关键词： Substance use disorder   FTIR   Serum   Blood   MDA   GSH  

摘要： Substance abuse such as opioids, cannabis, and alcohol causes activation on the immune system and the release of reactive oxygen species (ROS) into the blood and serum. These substances cause an effect on oxidant and an-tioxidant status in patients with substance abuse. Mainly, wide-open to the ROS are lipids and proteins included blood, which suffers peroxidation. In this study, for the first-time differentiation of the effects of cannabis, alcohol and other synthetic substances on blood and serum samples, were performed. For this purpose, the level of the malondialdehyde (MDA) and glutathione (GSH) in serum and red blood cells, was measured using biochemical assay methods and Fourier Transform InfraRed spectroscopy (FTIR). The results showed, that peroxidation which is dignified as the production of MDA was increased for substance use disorder (SUD) patients (18.01 +/- 2.97) compared to the control group (10.75 +/- 2.28) (p < 0.001) and for antioxidant capacity, GSH level were signifi-cantly increased for SUD patients (p < 0.001). For the discrimination of protein and lipid region obtained from FTIR spectroscopy, we extracted features by principal component analyze (PCA) of protein (1800 cm(-1) to 900 cm(-1)) and lipid (3200 cm(-1) to 2800 cm(-1)) regions for blood and serum samples collected from patients with different types of SUD and healthy control (HC) participants. For the consideration of lipid oxidation, lipid satu-ration, lipid desaturation and protein aggregation the peak heights at 1740 cm(-1) to 2960 cm(-1), 2920 cm(-1) to 2960 cm(-1), 3012 cm(-1) to 2960 cm(-1), and 1630 cm(-1) to 1650 cm(-1) regions were studied for SUD and HC. More-over, more visible changes were noticed for proteins region, than for lipids. The most notice structural changes were observed in amide II in serum spectra. Then we classified protein and lipid region's PCA results of blood and serum by Linear discriminant analysis (LDA) and Support vector machine (SVM). Confidence of th

关键词： Noise   Toluene   Toxicology   Nephrology   Occupational health   Pathology  

摘要： The biological and renal effects made by simultaneous and non-simultaneous exposure to toluene and noise were investigated. Twenty-four New Zealand white rabbits were exposed to 100 dB of white noise and 1000 ppm of toluene vapor for two weeks. The examined biochemical factors were urea, uric acid, creatinine, glucose, tri-glyceride, cholesterol, and albumin serum levels, measured on different days after the end of the exposure. Moreover, glutathione peroxidase activity (GPX), malondialdehyde dismutase activity (MDA), and superoxide dismutase (SOD) parameters were measured in the kidney tissue. The hematoxylin and eosin staining method was used for histopathological experiments. Overall, the noise increased albumin, uric acid, creatinine, and glucose levels, but it decreased urea, cholesterol, and triglyceride levels. Toluene decreased albumin, uric acid, and urea levels, while it increased creatinine, triglyceride, cholesterol, and glucose levels. Simultaneous exposure to noise and toluene decreased albumin, uric acid, cholesterol, and urea levels, whereas it increased creatinine, glucose, and triglyceride levels. GPX, MDA, and SOD levels increased by simultaneous and non simultaneous exposure to noise and toluene. Furthermore, massive tubular degeneration, tubular cell vacuolization, glomerular disorganization, congestion, glomerular cell shrinkage, and unclear brush border were detected in the kidney tissue.

关键词： Novel lectin   Characterization and purification   Antiviral and anticancer  

摘要： In the present study, a novel lectin was purified from the newly isolated cyanobacterium, Lyngabya confervoides MK012409 and tested for its antiviral and anticancer activity. Out of 30 isolates, Mabroka-s isolate which identified as Lyngabya confervoides MK012409 showed the highest agglutination titer. Lyngabyal lectin showed the greatest haemagglutination activity with pigeon/rabbit erythrocytes with a minimum concentration of 2.4 mu g/ml. Physical characterization of Lyngabyal lectin showed ability to keep the activity at a higher temperature up to 80 degrees C with stability over a wide pH range (4-8) as well as its stability toward chemical denaturants. Carbohydrate specificity test revealed that the sugar alcohols completely inhibited the lectin haemagglutination activity. The electrophoretic analysis revealed that the lyngabyal lectin is a 140 kDa composed of two 70 kDa subunits. Lyngabyal lectin was able to inhibit the proliferation of MCF-7 and Caco-2 cancer cell lines with IC50 values of 246 +/- 0.17 and 376.4 +/- 0.34 mu g/ml, respectively. Lyngabyal lectin also showed virucidal activity against HSV-1 with EC50 of 167 +/- 0.52 ng/ml and inhibited plaque formation in the HSV-1 infected Vero cells with EC50 of 84.94 +/- 0.34 ng/ml. These findings emphasize the ability of the lyngabyal lectin to fight breast and colon cancer besides it represents a promising antiviral agent. (C) 2020 Elsevier B.V. All rights reserved.

关键词： Stabilization  

摘要： Carbocations are important intermediates in the biosynthesis of terpenes and steroids, and it is challenging to try to understand how these relatively unstable species survive even transiently during biochemical reactions. Carbocation-pi interaction with aromatic amino acid residues is an important factor in helping to stabilize these positively charged species. However, the short lifetimes of these active site carbocations makes experimental evaluation of the stabilization afforded by such interaction impossible. Computational studies, however, have provided some insight into this phenomenon. Herein we report a simple, computationally efficient method to estimate such stabilization energies afforded by phenylalanine to biochemical carbocation intermediates. A model is constructed in which the biochemical carbocation is replaced by an appropriate carbocation mimic (t-butyl or dimethylallyl). This substitute carbocation is then aligned with an ethylbenzene serving as a surrogate for each proximate phenylalanine in a geometry that replicates as closely as possible the orientation of that phenylalanine using measurements made on an X-ray structure of an enzyme active site in which a carbocation surrogate is bound. Density functional theory computations on such models were then used to yield estimates of stabilization energies. Application of this method to the tertiary carbocation formed in the reaction catalyzed by geranyl diphosphate C-methyl transferase gave a stabilization energy (-12.3 kcal mol(-1)) that was essentially identical to that obtained previously by analysis of a much more computationally demanding model of the active site. As a check on the accuracy of the simpler method, it was applied with similar success to the farnesyl cation formed in the reaction catalyzed by aristolochene synthase that is stabilized by cation-pi interaction with two phenylalanines. Application of this method is also described to estimate carbocation-pi stabilization, by the same

关键词： Sediment   soil   Cucurbitaceae   plant condition   PCBs   Microtox  

摘要： Approximately 200 million m(3) of sediments are dredged every year in the United States. Of this amount, 2.3-9 million m(3) are contaminated to the extent that they require special, and often costly, handling. Therefore, there is a pressing need to develop appropriate technology for the safe utilization of these sediments, especially in the case of the Hudson River, which is well known to demonstrate significant polychlorinated biphenyls (PCBs) contamination. Hence, the aim of the present study was to examine the influence of different doses of Hudson River sediments (10%, 25%, 50%, 75% and 100% admixtures) on soil quality and on the biochemical and growth response of cucumber (Cucumis sativus L. cv 'Wisconsin SMR 58'), used as potential phytoremediation tool for sediment-borne PCBs. A sediment/soil admixture was found to significantly decrease the nitrogen (N) content in the substratum;in addition, phosphorus (P) content was significantly increased by 50-100% sediment, while potassium (K) content was significantly increased by 10% sediment, and significantly decreased by >50% sediment. Although sediment treatment resulted in a gradual increase in PCB content in the soil-sediment substratum, exceeding the threshold effect concentration (TEC) for the >= 50% sediment admixture, the Microtox assay did not suggest toxicity to microorganisms. The results demonstrated also that admixture of 10-25% Hudson River sediment increased cucumber growth;however, higher doses led to growth inhibition, manifested as lower biomass and smaller leaves. Also, chlorophyll a and b content decreased with increasing doses of sediment. Phenylpropanoid and flavonol contents were significantly higher in plants grown in soil amended with 10% of sediment, but significantly lower in soil treated with a 100% sediment admixture. The anthocyanin content in plants was lower at admixtures of 50% and higher. The obtained results corresponded with the decreasing content of N and K.

摘要： Advances in molecular biology continue to help us uncover how information written into genes provides a blueprint for the initiation and orchestration of programs and processes that control cell division, cell-type specification, cellmigration, cellular differentiation, and cell death. Clearly, molecular elements into which information is written must "talk to one another'' and "work with each other'' to generate appropriate cellular responses to cues and signals.

关键词： Propionic acidemia   Prenatal diagnosis   Amniotic fluid   Metabolite analysis   Propionylcarnitine  

摘要： Background Propionic acidemia (PA) is a serious metabolic disorder, and different approaches have been applied to its prenatal diagnosis. To evaluate the reliability and validity of a biochemical strategy in the prenatal diagnosis of PA, we conducted a retrospective study of our 11-year experiences at a single center. Methods We accumulated data from 78 pregnancies from 58 families referred to our center and provided prenatal diagnosis by directed genetic analysis and/or metabolite measurement using tandem mass spectrometry (MS/MS) and gas chromatography/mass spectrometry (GC/MS) of amniotic fluid (AF) samples. Results Sixty-five unaffected fetuses (83.33%) and 13 affected fetuses (16.67%) were confirmed in our study. The characteristic metabolites including propionylcarnitine (C3) level, C3/acetylcarnitine (C2) ratio and 2-methylcitric acid (2MCA) level in unaffected and affected groups showed significant differences (P < 0.0001), while the level of 3-hydroxypropionic acid (3HPA) showed no significant difference between the two groups (P > 0.05).Of the 78 pregnancies, 24 fetuses were found to have either one causative pathogenic variant or were without genetic information in the proband. Three of these fetuses had elevated AF levels of C3, C3/C2 ratio, and 2MCA and, thus, were determined to be affected, while the remaining fetuses were determined to be unaffected based on a normal AF metabolite profile. Our genetic and biochemical results were highly consistent with postnatal follow-up results on all unaffected fetuses. Conclusions We conclude that a biochemical approach can serve as a fast and convenient prenatal diagnostic method for pregnancies at an increased risk for PA, which could be used in conjunction with genetic testing for precise prenatal diagnosis of this disorder. In our analysis, the characteristic metabolites C3 level, C3/C2 ratio, and 2MCA level in AF supernatant were dependable biochemical markers for diagnosis, of which the C3/C2 ratio appears t