教学课程资源库 更多>>

关键词： [1-(Butylamino)-1-methylethyl]-phosphonic acid   Vitamin B12 supplementation   Phosphorus supplementation   Adenosine nucleotides   Hypoxia   Hypothermia   Cortisol elevation   Lysozyme reduction  

摘要： Butaphosphan {[1-(butylamino)-1-methylethyl]-phosphonic acid (BTP)}-cyanocobalamin [vitamin B-12 (C)], a combination drug comprising an organic source of phosphorus and a synthetic form of vitamin B-12, is used to attenuate stress responses in livestock. This study was performed to examine the effects of BTP-C in olive flounder Paralichthys olivaceus under normal and stressful conditions. P. olivaceus was intramuscularly injected with BTP-C (50-300 mg BTP-C/kg body weight) under normal conditions and changes in muscle adenosine nucleotides examined. BTP-C increased adenosine 5 '-triphosphate (ATP) levels;this effect was more pronounced at 22 degrees C than at 13 degrees C. Serum transaminase levels were also elevated at a dose of 300 mg BTP-C/kg, which suggested possible hepatotoxicity of the drug. Effects of BTP-C on stress were examined by injecting it at a rate of 50 mg/kg. BTP-C partially prevented hypothermia- and hypoxia-induced reduction in feeding. Serum immunoglobulin M levels were increased by BTP-C in these stress tests. Although BTP-C did not affect hypothermia-induced cortisol elevation or lysozyme reduction, changes in these parameters due to hypoxia were alleviated by the drug. Stress-attenuating effects of BTP-C were also confirmed in fish farms following injection of an antibiotic. These results indicate that BTP-C may be useful against various forms of stress in fish. Accelerated ATP production following the administration of BTP-C is one possible mechanism resulting in the attenuation of stress effects. The clinically effective dose of BTP-C, 50 mg/kg, did not cause any marked toxicity in P. olivaceus.

关键词： Microorganism   Soil activity   Chlorophyll content   Enzymatic activity   Bioherbicides   Random mutagenesis  

摘要： In this study, the active metabolites from both the wild strain of Lasiodiplodia pseudotheobromae C1136 and three genetically enhanced strains of C1136 were obtained through random mutagenesis. The effect of the active metabolites from these strains was evaluated in relation to physiological, biochemical, and ultrastructural changes on the leaves of two weeds (Amaranthus hybridus and Echinochloa crus-galli). The phytotoxic metabolites secreted by the genetically enhanced strains showed a decrease in the pigments (chl a, chl b, and carotenoids), carbohydrate content, and the amino acid profile. On the other hand, an increase in total phenols of the tested leaves was observed when compared with the untreated leaves. The scanning electron microscopy showed the presence of damages, necrosis, degradation, and ultrastructural changes on the tested leaf tissues of the weeds. Also, increased lipid peroxidation and electrolyte leakage were also observed on the tested weeds treated with phytotoxic metabolites secreted by the genetically enhanced strains. We also showed that the phytotoxins from the strains of C1136 are biocompatible and that it improved soil CO2 evolution, organic carbon content, and enzymatic activity (acidic and alkaline phosphatase, dehydrogenases, cellulase, catalase). The study validates the severe pathological effects of phytotoxic metabolites from the strains of C1136 on the leaves of the weeds presented in this study. The mode of action of the phytotoxic metabolites produced from this bioherbicidal isolates will go a long way in preventing environmental hazards.

关键词： Anaerobic digestion   Alkali pretreatment   Ultrasounds   Microwaves   Lignocellulosic biomass  

摘要： This study aims to investigate the effects of microwaves, ultrasonic and alkaline pretreatments on olive pomace properties and its biomethane potential. Alkaline pretreatment was found to reduce lipid and fiber contents (especially lignin) and to increase soluble matter. The alkali pretreatment at a dose of 8% (w/w TS) under 25 degrees C and for 1 day removed 96% of initial lipids from the solid olive pomace. Unlike NaOH addition, mild microwaves and ultrasonic pretreatments had no impact on lignin. However, in the case of long microwaves pretreatment (450 W-10 min), cellulose and lignin contents were reduced by 50% and 26% respectively. Similarly, the combination of ultrasonic and alkali reagent showed a positive effect on fiber degradation and lipid solubilization as well as a positive impact on methane production. Statistical analysis highlighted the correlation between NaOH dose, solubilization and methane production. The alkaline pretreatment at ambient temperature appeared the most energetically efficient.

关键词： protein crystallization   ubiquitylation (ubiquitination)   protein degradation   autophagy   p62 (sequestosome 1(SQSTM1))   LC3B   N-end rule   NTAQ1   PRT1   UBR box  

摘要： The N-degron pathway, formerly the N-end rule pathway, is a protein degradation process that determines the half-life of proteins based on their N-terminal residues. In contrast to the well-established in vivo studies over decades, in vitro studies of this pathway, including biochemical characterization and high-resolution structures, are relatively limited. In this study, we have developed a unique fusion technique using microtubule-associated protein 1A/1B light chain 3B, a key marker protein of autophagy, to tag the N terminus of the proteins involved in the N-degron pathway, which enables high yield of homogeneous target proteins with variable N-terminal residues for diverse biochemical studies including enzymatic and binding assays and substrate identification. Intriguingly, crystallization showed a markedly enhanced probability, even for the N-degron complexes. To validate our results, we determined the structures of select proteins in the N-degron pathway and compared them with the Protein Data Bank?deposited proteins. Furthermore, several biochemical applications of this technique were introduced. Therefore, this technique can be used as a general tool for the in vitro study of the N-degron pathway.

关键词： Biochemistry  

摘要： Despite being recognized as a therapeutic target in the processes of cancer cell proliferation and metastasis for over 50 years, the interaction of the urokinase plasminogen activator uPA with its receptor uPAR still needs an improved understanding. High resolution crystallographic data (PDB 2FD6) of the uPA-uPAR binding geometry was used to perform quantum biochemistry computations within the density functional theory (DFT) framework. A divide to conquer methodology considering a mixed homogeneous/inhomogeneous dielectric model and explicitly taking water molecules into account was employed to obtain a large set of uPA-uPAR residue-residue interaction energies. In order of importance, not only were Phe25 > Tyr24 > Trp30 > Ile28 shown to be the most relevant uPA residues binding it to uPAR, but the residues Lys98 > His87 > Gln40 v Asn22 > Lys23 > Val20 also had significant interaction energies, which helps to explain published experimental mutational data. Furthermore, the results obtained with the uPA-uPAR in/homogeneous dielectric function show that a high dielectric constant value epsilon = 40 is adequate to take into account the electrostatic environment at the interface between the proteins, while using a smaller value of epsilon (<10) leads to an overestimation of the uPA-uPAR binding energy. Hot spots of the uPA-uPAR binding domain were identified and a quantum biochemistry description of the uPAR blockers uPA(21 30) and cyclo(21,29)uPA(21-29)[(S21C;H29C)] was performed, demonstrating that cyclization improves the stability of mimetic peptides without compromising their binding energies to uPAR.

关键词： Blood   Snakes   Blood plasma   Hematology   Biochemistry   Gas analysis   Glucose   Reptiles  

摘要： Hematology, plasma biochemistry, and blood gas analysis were performed on venous samples obtained from free-ranging Eastern Copperheads (Agkistrodon contortrix) and Eastern Ratsnakes (Pantherophis alleghaniensis) in central North Carolina during a mark-recapture study conducted from April to October 2015 at the North Carolina Zoo. Blood samples were collected from 31 (15 male and 16 female) free-ranging copperheads and 34 (20 male and 14 female) free-ranging ratsnakes at the beginning and end of restraint. Restraint was performed for morphometric measurements, sex determination, and identification via placement of intracelomic passive integrated transponder (PIT) tags and marking of ventral scutes with a handheld electrocautery unit. Blood gas analytes were measured at the beginning of restraint and compared to analytes measured at the end to evaluate for changes secondary to handling. Total restraint time prior to the first blood sampling was 1.4 +/- 0.4 mins (mean +/- SD) and 1.0 +/- 0.2 mins (mean +/- SD) and restraint time prior to second blood sampling was 12.5 +/- 2.4 mins (mean +/- SD) and 13.5 +/- 3.4 mins (mean +/- SD) for copperheads and ratsnakes, respectively. Blood lactate concentrations at the beginning of restraint were similar for both species. Lactate concentrations increased significantly and pH decreased significantly for both species at the end of restraint when compared to the beginning of restraint. Furthermore, lactate concentrations at the end of restraint were significantly elevated in ratsnakes compared to copperheads. This study provides guidelines for interpretation of venous hematology, plasma biochemistry, and blood gas values for free-ranging copperheads and ratsnakes in central North Carolina and demonstrates the physiological response to venous blood gas analytes secondary to capture and restraint.

关键词： Chromium   Triticum aestivum L   seedlings   attenuated total reflectance Fourier transform infrared spectroscopy and synchrotron radiation induced X-ray fluorescence  

摘要： With mounting pressure of heavy metal pollution on agriculture, the demand of practical tools and protocols for nondestructive, pre-visual detection of plant response towards heavy metals has received great impetus. Advances in modern spectroscopic techniques such as synchrotron radiation X-ray fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy have the capability of providing a complete picture of the metabolic events taking place in plants stressed with heavy metals without subjecting the sample to pre-processing. The present study explores the utility of synchrotron radiation X-ray fluorescence and attenuated total reflectance Fourier transform infrared spectroscopy along with multivariate analysis for the detection of the response as spectral indices of wheat seedlings towards chromium treatment. For this, wheat has been grown under optimized growth conditions and exposed to chromium at concentrations from 20 to 100 mu M. The synchrotron radiation X-ray fluorescence spectra of control and chromium exposed seedlings show that exposure to chromium leads to its accumulation in the leaves of wheat seedlings which results in a reduction of the uptake of calcium, potassium, manganese iron, copper and zinc by the seedlings. The alterations in the biochemicals of wheat seedlings as a result of chromium exposure have been assessed by attenuated total reflectance Fourier transform infrared spectroscopy. Analysis of the infrared data reveals that chromium significantly alters the spectral signatures of cellulose, pectin, hemicelluloses, lignin, amide II, amide I and lipid in the leaves of wheat seedlings. The observed changes are dependent on the dose of chromium. The spectral signatures obtained in this study serve as important monitoring indices for observing alterations in the physiological, biochemical and metabolic status of plants under heavy metal stress.

关键词： 高职院校   生物化学   教学改革  

摘要： 本文笔者针对高职院校生物化学课程教学现状,结合自身教学实践,从培养学生兴趣、改革教学方法、改进实验教学和建立科学课程评价体系等方面对生物化学课程教学改革进行了初步探讨。