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关键词： Upper-Division Undergraduate   Biochemistry   Testing/Assessment   Internet/Web-Based Learning   Student-Centered Learning  

摘要： Oral exams may be as old as academia itself, but they are now rare in STEM undergraduate courses in the U.S. Can they be resurrected to help students develop oral communication skills, foster a sense belonging to a scholarly community, and change how students approach learning? This past spring, as we transitioned to emergency remote learning, my 50 students and I tried group oral exams as a primary assessment method in a survey of biochemistry course. The reasons for changing the assessment method were (1) to create the need for students to talk and connect to each other and (2) to have an assessment that is resistant to cheating. In group oral exams, students have to both talk and listen;they not only demonstrate their learning but also learn from each other. More importantly, preparation for group oral exams creates the need for students to work with their teammates to construct a shared understanding of the concepts and engage in learning together. During oral exams, the instructor can provide immediate feedback and support students in their learning journey by nudging them to reach deeper into their stored knowledge and to connect related ideas. Implementation of group oral exams proved to be challenging for the following reasons: (1) students were anxious about the unfamiliar testing method;(2) it was difficult to assess some of the course learning objectives;and (3) it was difficult to assess the broad range of learning objectives because of time constraints. Despite these concerns, I believe that the alignment of team learning activities with group oral exams helped students engage in deeper learning and build a supportive community in a time of crisis.

关键词： Second-Year Undergraduate   Organic Chemistry   Demonstrations   Biochemistry   Distance Learning/Self Instruction   Inquiry-Based/Discovery Learning   Acids/Bases   Proteins/Peptides   Carbohydrates   Noncovalent Interactions  

摘要： The COVID-19 pandemic has placed pressure on institutions, and especially instructors, to deliver course content in innovative ways, often with limited resources. In face-to-face learning, many chemistry instructors value inquiry-based learning with real-world applications. These types of learning activities cultivate student interest and, thus, motivate students to achieve their best. However, inquiry-based learning can be more challenging in an online environment, especially given limited resources and preparation time. This paper describes an inquiry-based laboratory demonstration that is inexpensive and easy to conduct outside of the traditional laboratory setting and yet provides a valuable learning experience for second-semester organic chemistry students. In this activity, students apply their knowledge of chemistry to the proteins, carbohydrates, and lipids in bovine milk, studying the casein protein, lactose, fatty acids, and more. Students complete a pre-lab assignment individually, watch prerecorded demonstrations via the Zoom video-conferencing platform, and complete a guided inquiry worksheet in groups, via breakout rooms. These activities help students review concepts such as solubility, hydrogen bonding, and acidity and invite them to apply new material on carbonyl chemistry, hydrolysis, and the relationship between protein structure and function. Because this learning activity challenges students to explore real-world implications, it deepens their understanding of the intricate interplay between organic chemistry, biochemistry, and microbiology and thus prepares them for further scientific inquiry in these areas.

关键词： Upper-Division Undergraduate   Biochemistry   History/Philosophy   Internet/Web-Based Learning   Student-Centered Learning   Metabolism  

摘要： The combination of the COVID-19 pandemic and social unrest turned education on its head this quarter. To keep students engaged, a plethora of techniques were employed, ranging from synchronous lectures and activities via the Zoom platform to the asynchronous online discussion board Piazza. Consideration of students nonacademic struggles also resulted in course modifications. This last method may have been the most effective in promoting student engagement, especially during the remaining 2 weeks of the quarter with increasing worldwide social unrest.

关键词： Upper-Division Undergraduate   Biochemistry   Laboratory Instruction   Computer-Based Learning   Distance Learning/Self Instruction   Inquiry-Based/Discovery Learning   Internet/Web-Based Learning   Enzymes   Molecular Modeling   Undergraduate Research  

摘要： Campus shutdowns during the SARS-CoV-2 pandemic posed unique challenges to faculty and students engaged in laboratory courses. Formerly hands-on experiments had to be quickly pivoted to emergency remote learning. While some resources existed prior to this period, many currently available online modules and/or simulations focus on a single technique. The Biochemistry Authentic Scientific Inquiry Lab (BASIL) curriculum has, for several years, provided a robust, linked, holistic inquiry experience that allows students to make connections between multiple techniques, both computational in nature as well as wet-lab-based. As a course-based undergraduate research experience (CURE), this flexible, module-based curriculum allows students to generate original hypotheses based on analysis of proteins of unknown function. We have taught this curriculum as the upper-level laboratory course on our campuses and were obliged to transition to remote instruction at various points in the course sequence. We report on the experiences of faculty and students over the transition period in this course. Additionally, we report as a case study results of one of our campus ongoing discipline-based education research (DBER) on the BASIL curriculum prior to and during remote delivery.

关键词： Detergents   Monomers   Surfmers   Extraction   Membrane proteins  

摘要： Three monomers with a maltose polar head, an alkyl hydrogenated chain, and an acrylamide-based polymerizable moiety were synthesized. The self-assembly properties in aqueous solutions of these monomers were studied by means of isothermal titration calorimetry (ITC), surface tension (SFT) measurements, and dynamic light scattering (DLS), which indicated the formation of small micellar aggregates of about 6 nm diameter. The critical micellar concentration (CMC) was found to depend on the length of the alkyl chain and on the nature of the polymerizable moiety, ranging from 0.35 mmto ca. 10 mm. The monomers were found to solubilize phospholipid vesicles and to extract a broad range of proteins fromEscherichia colimembranes. Finally, the extraction of two membrane proteins, namely, the full-length, wild-type human G-protein-coupled receptor (GPCR) adenosine A2A receptor (A(2A)R) and the bacterial transporter AcrB was demonstrated.

关键词： Akkermansia muciniphila   beta-N-acetylhexosaminidases   Mucin degradation   Crystal structure   Catalytic mechanism   Enzymatic characteristics  

摘要： beta-N-acetylhexosaminidases from the gut microbes are found to be capable of cleaving the specific glycoside linkages in the process of mucin degradation that has relevance for human health. However, features of the enzyme used in regulating the sugar-degrading capacities of Akkermansia muciniphila have not been well defined. Here we reported the crystal structure of a novel beta-N-acetylhexosaminidase from Akkermansia muciniphila (Am0868), which displayed a typical (beta/alpha)(8) barrel fold with a GlcNAc bound to the active center. Crystallographic and subsequent mutagenic analyses confirmed that Asp326 and Glu327 are the key catalytic residues of Am0868. Furthermore, Am0868 exhibited high specificity to beta-GlcNAc supporting the substrate-assisted catalytic mechanism. Am0868 was also active in a broad pH and temperature range but inhibited strongly by metal ions Zn2+ and Cu2+ . Collectively, these results indicate that Am0868 has the potential for mucin hydrolysis under some severe conditions, which highlight the superiority of A. muciniphila surviving in gut. (c) 2020 Elsevier Inc. All rights reserved.

关键词： Post-mortem   biochemistry   cerebral spinal fluid   CSF   vitreous humour  

摘要： Cerebrospinal fluid (CSF) and vitreous humour (VH) can be biochemically analysed post-mortem. CSF can be aspirated from the ventricular system (VA) and from lumbar puncture (LP), whereas, VH is aspirated from the orbits. This study compared the biochemical constituents between CSF and VH in 20 post-mortem subjects as well as the effect post-mortem interval and subject age have on these variables. VH samples had significantly higher sodium (Na) and chloride (Cl) and lower magnesium (Mg), potassium (K), urea (Ur) and creatinine (Cr) compared with CSF samples. No statistically significant difference was demonstrated with beta-hydroxybutyrate (BHB) and glucose levels in both VH and both CSF samples. Interestingly, some of the differences in the biochemical analysis correlated with age, but none with post-mortem interval. In addition to sampling and pre-analytical sample processing differences, there may also be ante- and post-mortem factors explaining these observations. This study suggests that post-mortem CSF and VH are biochemically different and reference ranges for VH are not recommended for use in CSF samples.

关键词： Broiler   gut health and function   microbiome   plasma biochemical profile   seaweed blend  

摘要： 1. A total of 864 d old (male) Ross x Ross 708 broiler chicks were allocated to 48 floor pens (12 pens/treatment and 18 birds/pen) to investigate dose-response of a blend of seaweeds (SB) on growth performance, breast yield, jejunal histomorphology, microbial metabolites and community and plasma biochemical profile. 2. A maize-soybean meal diet was formulated with 0, 5, 10 or 20 g/kg of SB. Diets were formulated for a three-phase feeding programme (starter: d 0-10, grower: d 11-24, and finisher: d 25-42) and met or exceeded Aviagen nutrient specifications. Diets were allocated to pens (n = 12) balanced for body weight (BW). Birds had free access to feed and water, BW and feed intake (FI) were monitored by phase. One bird per pen was randomly selected on d 42, bled for plasma, and samples for intestinal tissue and caecal digesta were taken. Microbial DNA was extracted and submitted for microbial community profile using the Illumina Miseq (R) platform. 3. In the starter phase, SB linearly (P <= 0.01) improved BW, body weight gain (BWG), and FCR. However, the improvement was quadratic, such that there was no further improvement beyond 5 g/kg SB inclusion. Growth performance response to SB in the grower phase was similar to the starter phase, with the exception of FCR (P> 0.05). Overall, from d 0-42, a linear and quadratic (P< 0.01) response was observed for final BW (d 42), whereby birds fed 5, 10 and 20 g/kg SB were heavier than control by 166, 183 and 180 g, respectively. A quadratic (P= 0.03) effect was observed for breast yield in response to SB. There was a quadratic reduction (P< 0.05) in gamma-glutamyl transferase (GGT) and a linear increase in glutamate dehydrogenase (GDH) in response to SB. Supplemental SB linearly reduced (P <= 0.04) the relative abundance of phylumBacteroidetesandProteobacteria, and increased the abundance of phylumFirmicutes(linearly;P= 0.02) andActinobacteria(quadratically;P= 0.03). 4. The data indicated that the optimal inclusion for SB w

关键词： Post-mortem biochemistry   post-mortem interval   nature of death   vitreous humour  

摘要： Post-mortem biochemistry as a tool for the establishment of post-mortem interval (PMI) and the nature of death is very useful in Legal Medicine. Currently, several matrices are used for these investigations, although vitreous humour is the most useful for biochemical analysis due to its stability and low susceptibility to autolytic changes. The purpose of this study was to analyse to what extent the nature of death could influence in the measurement of parameters such us potassium (K+), hypoxanthine (Hx) and uric acid in the establishment of PMI. Samples of vitreous humour were collected from the eyes of 250 dead bodies (174 males, 76 females) with a mean age of 58.75 +/- 20.84 years, mean PMI of 15.56 +/- 6.21 hours post-mortem (hpm) and different causes of death, including natural (n = 148) and violent (n = 101) deaths. The vitreous humour was treated and the resultant supernatant was used for the biochemical analysis. Multichannel Autoanalyser was used to determine the concentrations of K+ and uric acid (mmol/L), and Hx (mu mol/L) was quantified by HPLC-UV. The results showed the measurement of K+, Hx and uric acid together could be a complementary tool for establishing the PMI because these parameters provide good results.

关键词： computational chemistry   dynamics   force-field   molecular modeling   molecular structures  

摘要： Modern chemistry seems to be unlimited in molecular size and elemental composition. Metal-organic frameworks or biological macromolecules involve complex architectures and a large variety of elements. Yet, a general and broadly applicable theoretical method to describe the structures and interactions of molecules beyond the 1000-atom size regime semi-quantitatively is not self-evident. For this purpose, a generic force field named GFN-FF is presented, which is completely newly developed to enable fast structure optimizations and molecular-dynamics simulations for basically any chemical structure consisting of elements up to radon. The freely available computer program requires only starting coordinates and elemental composition as input from which, fully automatically, all potential-energy terms are constructed. GFN-FF outperforms other force fields in terms of generality and accuracy, approaching the performance of much more elaborate quantum-mechanical methods in many cases.