A Laboratory-intensive Course on RNA Interference and Model Organisms

RNA interference (RNAi) is a powerful method to silence gene expression in a variety of organisms and is generating interest not only as a useful tool for research scientists but also as a novel class of therapeutics in clinical trials. Here, we report that undergraduate and graduate students with a basic molecular biology background were able to demonstrate conceptual knowledge and technical skills for using RNAi as a research tool upon completion of an intensive 8-wk RNAi course with a 2-h lecture and 5-h laboratory per week. Students were instructed on design of RNAi experiments in model organisms and perform multiweek laboratory sessions based on journal articles read and discussed in class. Using Nicotiana benthamiana, Caenorhabditis elegans, and mammalian cell culture, students analyzed the extent of silencing using both qualitative assessment of phenotypic variations and quantitative measurements of RNA levels or protein levels. We evaluated the course over two semesters, each with a separate instructor. In both semesters, we show students met expected learning outcomes as demonstrated by successful laboratory experiment results, as well as positive instructor assessments of exams and lab reports. Student self-assessments revealed increased confidence in conceptual knowledge and practical skills. Our data also suggest that the course is adaptable to different instructors with varying expertise.     

Virtual Transgenics: Using a Molecular Biology Simulation to Impact Student Academic Achievement and Attitudes

The transgenic mouse model is useful for studying the causes and potential cures for human genetic diseases. Exposing high school biology students to laboratory experience in developing transgenic animal models is logistically prohibitive. Computer-based simulation, however, offers this potential in addition to advantages of fidelity and reach. This study describes and evaluates a computer-based simulation to train advanced placement high school science students in laboratory protocols, a transgenic mouse model was produced. A simulation module on preparing a gene construct in the molecular biology lab was evaluated using a randomized clinical control design with advanced placement high school biology students in Mercedes, Texas (n?=?44). Pre-post tests assessed procedural and declarative knowledge, time on task, attitudes toward computers for learning and towards science careers. Students who used the simulation increased their procedural and declarative knowledge regarding molecular biology compared to those in the control condition (both p?<?0.005). Significant increases continued to occur with additional use of the simulation (p?<?0.001). Students in the treatment group became more positive toward using computers for learning (p?<?0.001). The simulation did not significantly affect attitudes toward science in general. Computer simulation of complex transgenic protocols have potential to provide a ??virtual?? laboratory experience as an adjunct to conventional educational approaches.     

How golden is silence? Teaching undergraduates the power and limits of RNA interference

It is hard and getting harder to strike a satisfying balance in teaching. Time dedicated to student-generated models or ideas is often sacrificed in an effort to “get through the syllabus.” I describe a series of RNA interference (RNAi) experiments for undergraduate students that simultaneously explores fundamental concepts in gene regulation, develops cutting-edge laboratory skills, and embraces student-directed learning. Students design a small interfering RNA (siRNA) against luciferase, add it to cells expressing this gene, and then quantitatively assess the siRNA's effect on both intended and unintended targets, using a luciferase assay and a DNA microarray. Because both RNAi and microarray technologies are relatively new, with no clear consensus on their analysis or limitations, students are encouraged to explore different approaches to the design of their reagents and interpretations of their data. The ability to creatively formulate a hypothesis-driven experimental approach to a scientific question and to critically evaluate collected data is stressed. Equally important, this experiment emphasizes how modern scientific ideas emerge, are debated, tested, and decided.     

From Genes to Proteins to Behavior: A Laboratory Project That Enhances Student Understanding in Cell and Molecular Biology

In the laboratory, students can actively explore concepts and experience the nature of scientific research. We have devised a 5-wk laboratory project in our introductory college biology course whose aim was to improve understanding in five major concepts that are central to basic cellular, molecular biology, and genetics while teaching molecular biology techniques. The project was focused on the production of adenine in Saccharomyces cerevisiae and investigated the nature of mutant red colonies of this yeast. Students created red mutants from a wild-type strain, amplified the two genes capable of giving rise to the red phenotype, and then analyzed the nucleotide sequences. A quiz assessing student understanding in the five areas was given at the start and the end of the course. Analysis of the quiz showed significant improvement in each of the areas. These areas were taught in the laboratory and the classroom; therefore, students were surveyed to determine whether the laboratory played a role in their improved understanding of the five areas. Student survey data demonstrated that the laboratory did have an important role in their learning of the concepts. This project simulated steps in a research project and could be adapted for an advanced course in genetics.     

Using reasoning ability as the basis for assigning laboratory partners in nonmajors biology

Students in a large one-semester nonmajors college biology course were classified into one of three groups (intuitive—I, transitional—T, reflective—R) based upon a pretest of scientific reasoning ability. Laboratory teams of two students each then were formed, such that all possible combinations of reasoning abilities were represented (i.e., I-I, I-T, I-R, T-T, T-R, R-R). Students worked with their assigned partners during each of the course's 14 laboratory sessions. Gains in reasoning ability, laboratory achievement, and course achievement, as well as changes in students' opinions of their motivation, enjoyment of the laboratory, and their own and their partner's reasoning abilities were assessed at the end of the semester. Significant pre- to posttest gains in reasoning ability by the intuitive and transitional students were found, but these gains were not significantly related to the laboratory partner's reasoning ability. Also, course achievement was not significantly related to the laboratory partner's reasoning ability. Students were perceptive of others' reasoning ability; the more able reasoners were generally viewed as being more motivated, having better ideas, and being better at doing science. Additional results also indicated that course enjoyment and motivation was significantly decreased for the transitional students when they were paired with intuitive students. Apparently, for students in transition (i.e., not at an equilibrium state with regard to reasoning level), it is frustrating to work with a less able reasoner. However, some evidence was found to suggest that reflective students may benefit from working with a less able partner.     

3-溴丙酮酸对秀丽隐杆线虫的毒性和代谢的影响（英文）

目的:通过3-溴丙酮酸(3-BrPA)处理秀丽隐杆线虫(Caenorhabditis elegans),观察3-BrPA对线虫的毒性和生存周期的影响。通过秀丽隐杆线虫RNA干扰(RNAi)和突变株,分析3-BrPA对线虫糖酵解途径己糖激酶家族和药物代谢的关键酶细胞色素P450(cytochrome P450,CYP)家族的影响。创新点:首次报道了3-BrPA对秀丽隐杆线虫有毒性作用,己糖激酶是3-BrPA对线虫作用的重要靶点,而CYP-35A家族是线虫代谢3-BrPA的主要酶类。方法:用不同浓度的3-BrPA处理秀丽隐杆线虫,每24 h监测一次存活率;用实时荧光定量聚合酶链反应(qPCR)检测代谢相关基因的表达;通过RNAi沉默己糖激酶家族基因hxk-1、hxk-2和hxk-3;计算3-BrPA处理hxk家族RNAi株和细胞色素P450 cyp-35家族突变株后的致死中浓度(LC50)。结论:3-BrPA对线虫有明显的毒性效应(图1);与对照组比较,3-BrPA处理组的线虫平均寿命明显缩短(图2);3-BrPA处理线虫后hxk-1、hxk-2和hxk-3的信使RNA(mRNA)表达明显升高(P<0.05,图5);3-BrPA处理hxk RNAi株后的LC50均减小(P<0.05,表5);3-BrPA处理cyp-35突变株后的LC50也均减小(P<0.05,表6)。综上所述,3-BrPA的毒性与其对秀丽隐杆线虫己糖激酶代谢的影响密切相关;CYP-35家族在线虫中对3-BrPA代谢中起着关键作用。     

Experimenting with spirituality: analyzing The God Gene in a nonmajors laboratory course

References linking genes to complex human traits, such as personality type or disease susceptibility, abound in the news media and popular culture. In his book The God Gene: How Faith is Hardwired into Our Genes, Dean Hamer argues that a variation in the VMAT2 gene plays a role in one's openness to spiritual experiences. In a nonmajors class, we read and discussed The God Gene and conducted on a small scale an extension of the study it describes. Students used polymerase chain reaction to replicate a portion of their VMAT2 genes, and they analyzed three polymorphic sites in the sequence of these products. Associations between particular VMAT2 alleles and scores on a personality test were assessed by t test. The course, of which this project was a major part, stimulated student learning; scores on a test covering basic genetic concepts, causation/correlation, and laboratory methodology improved after completion of the course. In a survey, students reported the laboratory project aided their learning, especially in the areas of statistics and the linking of genes to behaviors. They reported high levels of engagement with the project, citing in particular its personal nature as motivating their interest.     

Delayed benefits of learning elementary algebraic transformations through contrasted comparisons

Students studying algebra often make mistakes because of superficial similarities between addition and multiplication problems. In two experiments, we investigated whether these errors can be prevented by presenting addition and multiplication problems in such a way that students are encouraged to compare the problems at a deeper level. In Experiment 1, 72 sixth graders were assigned to two self-learning programs. In the contrast program, addition and multiplication were mixed and juxtaposed. In the sequential program, students first received only addition problems followed by multiplication problems. The results revealed that during the training, students performed worse under the contrast condition. However, in the follow-up tests (1-day, 1-week, 3-months), these findings were reversed: the contrast group clearly outperformed the sequential group. The findings were replicated under improved methodological conditions in Experiment 2 with 154 sixth graders. These experiments show that contrasted comparison of superficially similar but conceptually different material results in improved long-term learning.     

Using comparative genomics for inquiry-based learning to dissect virulence of Escherichia coli O157:H7 and Yersinia pestis

Genomics and bioinformatics are topics of increasing interest in undergraduate biological science curricula. Many existing exercises focus on gene annotation and analysis of a single genome. In this paper, we present two educational modules designed to enable students to learn and apply fundamental concepts in comparative genomics using examples related to bacterial pathogenesis. Students first examine alignments of genomes of Escherichia coli O157:H7 strains isolated from three food-poisoning outbreaks using the multiple-genome alignment tool Mauve. Students investigate conservation of virulence factors using the Mauve viewer and by browsing annotations available at the A Systematic Annotation Package for Community Analysis of Genomes database. In the second module, students use an alignment of five Yersinia pestis genomes to analyze single-nucleotide polymorphisms of three genes to classify strains into biovar groups. Students are then given sequences of bacterial DNA amplified from the teeth of corpses from the first and second pandemics of the bubonic plague and asked to classify these new samples. Learning-assessment results reveal student improvement in self-efficacy and content knowledge, as well as students' ability to use BLAST to identify genomic islands and conduct analyses of virulence factors from E. coli O157:H7 or Y. pestis. Each of these educational modules offers educators new ready-to-implement resources for integrating comparative genomic topics into their curricula.     

The effectiveness of using incorrect examples to support learning about decimal magnitude

Comparing common mathematical errors to correct examples may facilitate learning, even for students with limited prior domain knowledge. We examined whether studying incorrect and correct examples was more effective than studying two correct examples across prior knowledge levels. Fourth- and fifth-grade students (N = 74) learned about decimal magnitude in a brief tutoring session. Students were randomly assigned to two conditions: 1) comparing correct and incorrect examples (incorrect condition) or 2) comparing correct examples only (correct condition). The incorrect condition helped students learn correct procedures and key concepts more than the correct condition, including reducing misconceptions. Students’ prior knowledge of decimals did not interact with condition. Students’ explanations during the intervention revealed that those in the incorrect condition more frequently discussed correct concepts (e.g., the magnitude of a decimal and identifying misconceptions). Overall, contrasting incorrect examples with correct examples can help students learn correct concepts and procedures.     

The Python Project: A Unique Model for Extending Research Opportunities to Undergraduate Students

Undergraduate science education curricula are traditionally composed of didactic instruction with a small number of laboratory courses that provide introductory training in research techniques. Research on learning methodologies suggests this model is relatively ineffective, whereas participation in independent research projects promotes enhanced knowledge acquisition and improves retention of students in science. However, availability of faculty mentors and limited departmental budgets prevent the majority of students from participating in research. A need therefore exists for this important component in undergraduate education in both small and large university settings. A course was designed to provide students with the opportunity to engage in a research project in a classroom setting. Importantly, the course collaborates with a sponsor''s laboratory, producing a symbiotic relationship between the classroom and the laboratory and an evolving course curriculum. Students conduct a novel gene expression study, with their collective data being relevant to the ongoing research project in the sponsor''s lab. The success of this course was assessed based on the quality of the data produced by the students, student perception data, student learning gains, and on whether the course promoted interest in and preparation for careers in science. In this paper, we describe the strategies and outcomes of this course, which represents a model for efficiently providing research opportunities to undergraduates.     

A semester-long project for teaching basic techniques in molecular biology such as restriction fragment length polymorphism analysis to undergraduate and graduate students

Several reports on science education suggest that students at all levels learn better if they are immersed in a project that is long term, yielding results that require analysis and interpretation. I describe a 12-wk laboratory project suitable for upper-level undergraduates and first-year graduate students, in which the students molecularly locate and map a gene from Drosophila melanogaster called dusky and one of dusky's mutant alleles. The mapping strategy uses restriction fragment length polymorphism analysis; hence, students perform most of the basic techniques of molecular biology (DNA isolation, restriction enzyme digestion and mapping, plasmid vector subcloning, agarose and polyacrylamide gel electrophoresis, DNA labeling, and Southern hybridization) toward the single goal of characterizing dusky and the mutant allele dusky(73). Students work as individuals, pairs, or in groups of up to four students. Some exercises require multitasking and collaboration between groups. Finally, results from everyone in the class are required for the final analysis. Results of pre- and postquizzes and surveys indicate that student knowledge of appropriate topics and skills increased significantly, students felt more confident in the laboratory, and students found the laboratory project interesting and challenging. Former students report that the lab was useful in their careers.     

Counterintuitive effects of online feedback in middle school math: results from a randomized controlled trial in ASSISTments

This study compared the effects of three different feedback formats provided to sixth grade mathematics students within a web-based online learning platform, ASSISTments. A sample of 196 students were randomly assigned to one of three conditions: (1) text-based feedback; (2) image-based feedback; and (3) correctness only feedback. Regardless of condition, students solved a set of problems pertaining to the division of fractions by fractions. This mathematics content was representative of challenging sixth grade mathematics Common Core State Standard (6.NS.A.1). Students randomly assigned to receive text-based feedback (Condition A) or image-based feedback (Condition B) outperformed those randomly assigned to the correctness only group (Condition C). However, these differences were not statistically significant (F(2,108) = 1.394, p = .25). Results of this study also demonstrated a completion-bias. Students randomly assigned to Condition B were less likely to complete the problem set than those assigned to Conditions A and C. To conclude, we discuss the counterintuitive findings observed in this study and implications related to developing and implementing feedback in online learning environments for middle school mathematics.     

Inquiry-Based Laboratory Activities in Electrochemistry: High School Students’ Achievements and Attitudes

This study aimed to investigate the effects of inquiry-based laboratory activities on high school students’ understanding of electrochemistry and attitudes towards chemistry and laboratory work. The participants were 62 high school students (average age 17 years) in an urban public high school in Turkey. Students were assigned to experimental (N?=?30) and control groups (N?=?32). The experimental group was taught using inquiry-based laboratory activities developed by the researchers and the control group was instructed using traditional laboratory activities. The results of the study indicated that instruction based on inquiry-based laboratory activities caused a significantly better acquisition of scientific concepts related to electrochemistry, and produced significantly higher positive attitudes towards chemistry and laboratory. In the light of the findings, it is suggested that inquiry-based laboratory activities should be developed and applied to promote students’ understanding in chemistry subjects and to improve their positive attitudes.     

Incorporating a new bioinformatics component into genetics at a historically black college: outcomes and lessons

Many students at minority-serving institutions are underexposed to Internet resources such as the human genome project, PubMed, NCBI databases, and other Web-based technologies because of a lack of financial resources. To change this, we designed and implemented a new bioinformatics component to supplement the undergraduate Genetics course at Clark Atlanta University. The outcomes of the Bioinformatics course were assessed. During the first week of the semester, students were assigned the Felder-Soloman's Index of Learning Styles Inventory. The overwhelming majority of students were visual (82.1%) and sequential (75.0%) learners. Furthermore, pre- and postcourse surveys were administered during the first and the last week of the course to assess learning, confidence level, and mental activity. These indicated students increased the number of hours spent using computers and doing homework. Students reported confidence in using computers to study genetics increased, enabling them to better visualize and understand genetics. Furthermore, students were more mentally engaged in a more social learning environment. Although the students appreciated the value of the bioinformatics component, they reported the additional work load was substantial enough to receive additional course credit.     

The continuity of college students’ autonomous learning motivation and its predictors: A three-year longitudinal study

This study examined change in Chinese students’ autonomous learning motivation in the first three years of college and how this change is accounted for by intra- and inter-individual variables. The sample included 633 (328 female) college freshmen. Results showed that students’ autonomous learning motivation decreased over years in college. Students’ perceived parental autonomy support and peer relatedness demonstrated different change patterns over time, but each variable positively predicted students’ autonomous learning motivation. Students majoring in science showed a more rapid decline in motivation than liberal arts students. Students studying a major of their own choice showed a higher initial level of motivation than students who were studying a major not of their own choice, but no group difference in the declining trend of motivation was observed. The positive effects of students' perceived institutional support on motivation were limited to the freshmen year.     

Approaches to studying and perceptions of academic quality in a short web-based course

Both the Course Experience Questionnaire (CEQ) and the Revised Approaches to Studying Inventory (RASI) were administered to students who were taking an introductory web‐based course in computing. The constituent structure of both questionnaires was preserved in this distinctive context, and the students’ scores on the individual scales of the CEQ and the RASI shared over 80% of their variance. Students’ perceptions of academic quality were positively associated with their adoption of desirable approaches to studying and negatively associated with their adoption of undesirable approaches. Students’ academic attainment was positively associated with their perceptions of academic quality and their adoption of a strategic approach to studying and negatively associated with their adoption of a surface approach to studying.     

Marginal utility of social capital: the assistance of family and friends in choosing university studies

Abstract

We focus on transition from school or employment to university and analyze how social network characteristics and the quantity of social capital (SC) influence the assessment of help in selecting a program of study. We analyze data of undergraduate students at a German university and find that SC has an amount and a context effect. First, we assume that in networks where students find a lot of SC, they also receive helpful advice. Second, a social network close to academia offers useful help. Our multivariate analyses support the context effect, but also indicate a marginal utility of SC. Students with academically educated parents rate their parents’ help as more useful, and students with studying friends rate their friends’ advice as helpful. However, students who are rich in SC among family and friends rate their help lower than students who are rich in SC among only one part of their network.