教学课程资源库 更多>>

关键词： Li ion batteries   Corncob   Li3V2(PO4)(3)   Honeycomb framework   Self-assembly  

摘要： Li3V2(PO4)(3) (LVP) is a promising cathode for Li ion batteries (LIBs). But more effort need to do to improve its electronic conductivity. Honeycomb-like LVP@C materials with continuous carbon framework and hierarchical porous structure (macropores and mesopores) are successfully fabricated based on the nature lignocellulose fibers by biochemistry-directed self-assembly. The designed LVP@C has the advantage of large surface area, superior structure stability and short ion/electrons transport pathway. As the cathode for LIBs, it exhibits the initial specific capacity of 180 mAh g(-1) (91% of the theoretical specific capacity) with the energy density of 666 Wh/kg, which is much better than those reported in most literatures. Moreover, it also displays outstanding long-cycle performance with almost 100% capacity retained after 500 cycles. And most importantly, the biomass material used in the fabricating process is low-cost, renewable and environmentally friendly, which can decrease the present cost of the Li ion batteries (LIBs) and reduce the environmental pollution caused by batteries. The honeycomb-like structure puts forward a new strategy to develop high-performance polyanion-based materials for low cost and high-power LIBs. (C) 2021 Elsevier B.V. All rights reserved.

关键词： Hemoglobin  

摘要： We report how Raman difference imaging provides insight on cellular biochemistry in vivo as a function of sub-cellular dimensions and the cellular environment. We show that this approach offers a sensitive diagnostic to address blood biochemistry at the cellular level. We examine Raman microscopic images of the distribution of the different hemoglobins in both healthy (discocyte) and unhealthy (echinocyte) blood cells and interpret these images using pre-calculated, accurate pre-resonant Raman tensors for scattering intensities specific to hemoglobins. These tensors are developed from theoretical calculations of models of the oxy, deoxy and met forms of heme benchmarked against the experimental visible spectra of the corresponding hemoglobins. The calculations also enable assignments of the electronic transitions responsible for the colour of blood: these are mainly ligand to metal charge transfer transitions.

关键词： Amnesia   Bacopa monnieri   bacosides enriched fraction   bacosides free fraction   free radicals   scopolamine  

摘要： Bacopa monnieri(L.) Wettst. (BM) has been traditionally used in Ayurveda for improving memory and cognitive deficits which is also evidenced through experimental and clinical studies. The neuropharmacological properties of BM are attributed to "bacosides", a complex mixture of saponin compounds. BM extracts enriched with bacosides offers commercial advantage due to perceived higher efficacy. However, there is no scientific data to support the same. In the present study, methanolic extract of BM (BME) was compared with bacosides enriched (BME-EF) vis a vis bacosides free fraction (BME-FF). Potential antioxidant and cholinesterase inhibitory activity has been evaluated usingin vitroandin vivomethods. BME showed not only the highest anti-amnesic efficacy but also antioxidant and cholinesterase inhibitory activity, followed by either BME-FF or BME-EF. Interestingly, no significant differences were found in between the groups. These findings dispel the notion that bacosides enrichment enhances anti-amnesic efficacy and also suggests the contribution of other components.

关键词： Cell wall   cold-induced sweetening   invertase inhibitor   potato   reducing sugars   vacuolar  

摘要： Invertase inhibitors classified as cell wall/apoplastic and vacuolar belonging to the pectin methylesterase family, play a major role in cold-induced sweetening (CIS) process of potato tubers. The CIS process is controlled at the post-translational level via an interaction between invertase (cell wall/apoplastic and vacuolar) by their compartment-specific inhibitors (cell wall/apoplastic and vacuolar). Invertase inhibitors have been cloned, sequenced and functionally characterized from potato cultivars differing in their CIS ability. The secondary structure of the invertase inhibitors consisted of seven alpha-helices and four conserved cysteine residues. The well-conserved three amino acids i.e. Pro-Lys-Phe are known to interact with invertase. Location of the genes encoding cell wall/apoplastic and vacuolar invertase inhibitors on potato chromosome number twelve in a tandem orientation without any intervening genes suggest their divergence into the cell wall and vacuole forms following the event of gene duplication. Under cold storage conditions, the vacuolar invertase inhibitor gene showed developmentally regulated alternative splicing and produce hybrid mRNAs which were the result of mRNA splicing of an upstream region of vacuolar invertase inhibitor gene to a downstream region of the apoplastic invertase inhibitor gene. Transgenic potato tubers overexpressing invertase inhibitors resulted in decreased invertase activity, low reducing sugars and improved processing quality making invertase inhibitors highly potential candidate genes for overcoming CIS. Clustered regularly interspaced short palindromic repeats (CRISPR)/CRISPR-associated protein 9 (Cas9) gene-editing technology offers transgene-free breeding for developing CIS resistant potato cultivars. Moreover, the post-transcriptional regulation of invertase inhibitors during cold storage can be warranted. This review summarizes progress and current knowledge on biochemical and molecular approaches used for the

关键词： Human transferrin   Iron transport   Iron binding and release   Site-distribution   Post-translational modifications  

摘要： Transferrin (Tf) is an essential protein, probably ubiquitous to all metazoans. The main function of this family of proteins is to bind and transport ferric ions, increasing Fe(III) solubility under physiological conditions and preventing its deleterious pro-oxidant role in aerobic environments. In humans, Tf is responsible for the safe transport of this essential micronutrient through circulation and its delivery to requiring cells. Cellular uptake occurs through endocytosis mediated by the transferrin receptor (TfR). Although there is a good understanding of the general molecular mechanisms governing Tf iron binding and cellular iron delivery, several aspects of Tf biochemistry remain unclear. In this review, we provide an overview of the inorganic biochemistry of human Tf (hTf), exploring the available structural information on hTf and the hTf/TfR complex to discuss physiologically relevant aspects, such as iron binding site distribution, mechanism of iron loading and TfR priming of iron release in vivo. In addition, we consider the role of hTf microheterogeneity on its function. Post-translational modifications such as phosphorylation, glycation and oxidation may occur at relevant hTf sites, which will compromise iron binding, inter lobe cooperativity or interaction with the TfR. Furthermore, these modifications may contribute to the deregulation of systemic iron transport and distribution on a disease specific manner. Finally, a brief review of the role of hTf as one of the main blood serum ligands for toxic and therapeutic metal ions is presented. hTf is a long known and studied protein, but it is essential to understand the factors governing its expression and catabolism and how specific modifications modulate its function, in order to fully comprehend its role in human pathology or to explore its potential as a therapeutic agent. (C) 2021 The Author(s). Published by Elsevier B.V.

关键词： Biochar   Plant growth   Root morphology   Chlorophyll content   Total sugars   Flavonoids   Soil enzymes  

摘要： Impacts of biochar on growth, root morphological traits, plant physiological properties of basil (Ocimum basilicum) were studied in connection with an assessment of soil enzymatic activities. We hypothesised that the growth of basil is enhanced by an increase in root morphological traits, improved plant biochemical and physiological properties as well as by increased soil enzymatic activities after biochar application. Different concentrations of biochar derived from black cherry wood (1, 2 and 3%) were applied in pot experiments under greenhouse conditions at for 35 days. The results showed that biochar concentrations of 2% and 3% significantly increased plant height by 38% and 48%, leaf length by 15 and 24%, leaf number by 15% and 27% and leaf width by 36% and 50%, respectively, as compared with the control. The chlorophyll content, total sugar, flavonoids and soil enzymes activities were enhanced significantly with 2 and 3% biochar treatments. The total root length significantly increased by 30%, 46% and 61% with increasing levels of biochar, (1%, 2% and 3%), respectively. The biochar treatment of 3% significantly increased root surface area by 47%, root diameter by 37% and root volume by 45% over the control. The results showed that biochar improved plant morphological and physiological properties as well asactivities of soil enzymes, and thus finally promoted the growth and yield of basil and soil fertility.

关键词： Indian mustard   leaf biochemistry   photosynthesis   seed yield   stomatal size   trehalose  

摘要： Trehalose (Tre) is a nonreducing glucose disaccharide. It modulates diverse physio-biochemical processes in crop plants. A randomized pot experiment was designed to investigate whether the leaf-applied Tre could improve the growth, photosynthesis, leaf biochemistry, cell viability and yield of Indian mustard. Uniform surface sterilized seeds of mustard were sown in earthen pots. The plants were sprayed with four graded doses of Tre, viz. 0, 10, 20 or 30 mM using a hand sprayer twice at 50 and 70 days after sowing (DAS). The crop performance was assessed in terms of morpho-physiological, biochemical, microscopical and histochemical parameters at 80 DAS and yield attributes at harvest (120 DAS). The spray concentration of 10 mM Tre proved efficacious for all parameters studied, i.e. growth traits, relative water content, gas exchange parameters, enzyme activities, leaf glycine betaine and proline content, stomatal size and width, carbohydrate and mineral content, root cell viability and yield parameters. Moreover, foliar feeding of 10 mM Tre also reduced the generation of superoxide anion and hydrogen peroxide in mustard leaves, which were further confirmed with the fluorescence microscopy and histochemical localization examinations. The spray concentrations higher than 10 mM Tre were either equally or less effective. The foliar spray of 10 mM Tre increased shoot dry mass by 15.81%, chlorophyll content by 17.64%, photosynthetic rate by 17.04%, carbohydrate content by 22.40% and seed yield by 21.85% over the water -sprayed control. The data revealed the overall superiority of 10 mM Tre for improving the performance of In-dian mustard.

关键词： Upper-Division Undergraduate   Biochemistry   Enzymes   Laboratory Instruction   Hands-On Learning   Manipulatives   Fluorescence Spectroscopy   Kinetics  

摘要： Techniques and instrumentation that involve fluorescence are used in many careers related to biology and biochemistry. However, due to the expense of instrumentation, the theory and practice of fluorescence spectroscopy is commonly concentrated in instrumental analysis in most curricula, a class rarely required for biology and biochemistry majors. Biochemistry represents a course taken by these majors, providing an opportunity to expose them to the fundamentals of fluorescence. A three session laboratory series has been developed where the kinetic analysis of lactate dehydrogenase is carried out through the use of inexpensive, student-built fluorometers. These instruments are optimized for the detection of NADH fluorescence and constructed with interlocking building blocks (such as LEGO blocks), an LED source, a phototransistor detector, and other commercially available materials for a total cost of $52. Biochemistry students have built these spectrometers and used them to determine the Km of Gallus gallus lactate dehydrogenase for L-lactate and the kcat of this enzyme in accordance with literature values. Learning outcomes were assessed and indicate proficient understanding of instrument use and design.

关键词： Upper-Division Undergraduate   Biochemistry   Interdisciplinary   Multidisciplinary   Collaborative   Cooperative Learning   Communication   Writing   Inquiry-Based   Discovery Learning   Biosignaling   Metabolism   Student-Centered Learning  

摘要： Scientific knowledge is growing rapidly, particularly in biochemistry, an interdisciplinary subject in which the courses attract diverse students with varied disciplinary interests and career goals. Thus, there is a need to teach skills and concepts in biochemistry in a way that is both compelling to a variety of learners and also relevant to careers in science, health, and related areas. This article describes a pair of literature based group writing assignments developed for a two-semester biochemistry sequence with 30-50 students per section. Adaptable to application in many biochemistry courses, these projects reinforce core threshold concepts while teaching information literacy skills and connecting to biochemistry applications in medicine and technology. Strategies for structured instruction and management prior to and during work on the assignments are presented for instructors in order to maximize student success and impact. While writing assignments have become commonplace in upper-division biology courses, such a matched pair of mini-review assignments for a two-semester biochemistry sequence interweaving information literacy, core concepts, and applications has not been reported previously. Improved performance from the first to second semester indicates that these assignments help students learn skills that are useful for self-directed learning.