The aerobic biodegradation of common textiles that shed microfibers during laundering was evaluated under the action of microbes found in the environment, such as lake and seawater, and activated ...sludge at a low concentration from a wastewater treatment plant (WWTP). Under these conditions, the biodegradation potential was the same in all the experiments: Microcrystalline Cellulose (MCC) > Cotton > Rayon > Polyester/Cotton ≫ Polyester. Nevertheless, for cotton and rayon yarns, >70% biodegradation was achieved with activated sludge at low concentration and lake water, whereas in seawater, about 50% degradation was reached. Polyester did not appreciably degrade. The biodegradation results herein indicate potential not absolutes in nature. The bacterial diversity analyses in the different biodegradation inoculums show that there are distinct bacterial communities related to the assimilation and mineralization of complex carbohydrates that were promoted with the cellulosic MCC, cotton, and rayon samples different than the polyester sample.
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•The biodegradability was as follows: Microcrystalline Cellulose (MCC) > Cotton > Rayon > Polyester/Cotton >> Polyester.•The biodegradability depends on the chemical nature of the fibers and the microorganisms present in the environment.•The biodegradation achieved with activated sludge from the WWTP and lake water was higher than with the seawater.•The bacterial diversity analyses show that there are different communities developed in each inoculum system.•• There are distinct communities related to the biodegradable and non-degraded samples.
Genetically modified organisms (GMOs) are a topic of broad interest and are discussed in classes ranging from introductory biology to bioethics to more advanced methods-focused molecular biology ...courses. In most cases, GMOs are discussed in the context of introducing a single protein-coding gene to produce a single desired trait in a crop. For example, a commercially available kit allows students to test whether food products contain GMOs by detecting the
delta-endotoxin gene, which confers resistance to European corn borers. We have developed an 8-week laboratory module for upper-division undergraduates and graduate students that builds upon students' basic understanding of GMOs to introduce them to the techniques used to sustainably produce commercially valuable products in yeast through metabolic engineering. In this course, students use recombination-based methods to assemble genes encoding entire metabolic pathways in
, perform genetic screens to identify yeast genes that impact metabolite yield, and use error-prone PCR to optimize metabolic pathway function. In parallel to these laboratory-based activities, students engage with the societal impact of these approaches through case studies of products made via yeast metabolic engineering, such as opioids, omega-3 fatty acids, and the Impossible Burger. In this report, we focus on these case studies as well as an individual sustainability project assignment created for this course. This assignment, which spans the 8-week module, asks students to find examples of yeast metabolic engineering that could be used to address current sustainability challenges in their communities. By the end of the course, students synthesize this information to create a case study that could be used to teach concepts related to metabolic engineering and sustainability to their peers. Student approaches to this project have varied from literature reviews, to news searches, to directly contacting and interviewing researchers using novel metabolic engineering approaches. These student-produced projects are used as case studies in future semesters, amplifying student voices and contributing to student ownership. While developed in the context of this course, the sustainability project and case studies are broadly applicable and could be adapted for use in biology or bioethics courses at the undergraduate or graduate level. Through this report, we hope to gain collaborators interested in implementing a version of the course at their institutions, allowing for robust assessment of the impact of the course on a larger group of students.
Uropathogenic Escherichia coli (UPEC) is the leading cause of urinary tract infections (UTIs). A murine UTI model has revealed an infection cascade whereby UPEC undergoes cycles of invasion of the ...bladder epithelium, intracellular proliferation in polysaccharide-containing biofilm-like masses called intracellular bacterial communities (IBC), and then dispersal into the bladder lumen to initiate further rounds of epithelial colonization and invasion. We predicted that the UPEC K1 polysaccharide capsule is a key constituent of the IBC matrix. Compared to prototypic E. coli K1 strain UTI89, a capsule assembly mutant had a fitness defect in functionally TLR4⁺ and TLR4⁻ mice, suggesting a protective role of capsule in inflamed and noninflamed hosts. K1 capsule assembly and synthesis mutants had dramatically reduced IBC formation, demonstrating the common requirement for K1 polysaccharide in IBC development. The capsule assembly mutant appeared dispersed in the cytoplasm of the bladder epithelial cells and failed to undergo high-density intracellular replication during later stages of infection, when the wild-type strain continued to form serial generations of IBC. Deletion of the sialic acid regulator gene nanR partially restored IBC formation in the capsule assembly mutant. These data suggest that capsule is necessary for efficient IBC formation and that aberrant sialic acid accumulation, resulting from disruption of K1 capsule assembly, produces a NanR-mediated defect in intracellular proliferation and IBC development. Together, these data demonstrate the complex but important roles of UPEC polysaccharide encapsulation and sialic acid signaling in multiple stages of UTI pathogenesis.
Ensuring the public has a fundamental understanding of human–microbe interactions, immune responses, and vaccines is a critical challenge in the midst of a pandemic. These topics are commonly taught ...in undergraduate- and graduate-level microbiology and immunology courses; however, creating engaging methods of teaching these complex concepts to students of all ages is necessary to keep younger students interested when science seems hard. Building on the Tactile Teaching Tools with Guided Inquiry Learning (TTT-GIL) method we used to create an interactive
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operon molecular puzzle, we report here two TTT-GIL activities designed to engage diverse learners from middle schoolers to masters students in exploring molecular interactions within the immune system. By pairing physical models with structured activities built on the constructivist framework of Process-Oriented Guided Inquiry Learning (POGIL), TTT-GIL activities guide learners through their interaction with the model, using the Learning Cycle to facilitate construction of new concepts. Moreover, TTT-GIL activities are designed utilizing Universal Design for Learning (UDL) principles to include all learners through multiple means of engagement, representation, and action. The TTT-GIL activities reported here include a web-enhanced activity designed to teach concepts related to antibody–epitope binding and specificity to deaf and hard-of-hearing middle and high school students in a remote setting and a team-based activity that simulates the evolution of the Major Histocompatibility Complex (MHC) haplotype of a population exposed to pathogens. These activities incorporate TTT-GIL to engage learners in the exploration of fundamental immunology concepts and can be adapted for use with learners of different levels and educational backgrounds.
Scientific literacy is built on critical thinking. The postbaccalaureate workforce enhances our economies and societies by contributing a wealth of knowledge and skill sets to local communities, ...respective industries, and beyond as our world becomes increasingly interconnected. Education in scientific literacy should teach students how to learn about science and how to cultivate and communicate a positive attitude about science. Learners in a 200-level nonmajors biotechnology course engaged with a series of ethical dilemmas after mastering the basic elements of argument structure and advanced tools in argument evaluation. To introduce collaboration as a constructive process in undergraduate education, student interactions with peers require guidance, flexibility, and compassion to learn from each other. Students gain critical thinking mastery from two modules addressing how we argue and evaluate claims. Students apply these critical thinking skills to various ethical arguments involving responsible conduct of research training. Using our structured and interdisciplinary approach, new scholars learn through practice how to read, analyze, and evaluate research scenarios and respond to potential ethical situations. This strategy allows students to develop important scholarly skills, including a systematic approach to evaluating credibility and applying generosity to theirs and others' understanding of their circumstances.
Collaborative group learning and peer teaching are robust active learning techniques. Students and instructors interact with technology extensively in their lives and in the classroom. Technology ...facilitates collaborative group learning by enabling synchronous interaction with digital documents and immediate access to information. Though it is widely accepted that group learning is an improvement to traditional lectures, challenges in the design, execution, and evaluation of group learning can be a barrier to implementing this pedagogy in the higher education classroom. Divide and Conquer is a simple, easy-to-use, and modern technique that faculty and instructors can use to rapidly transform traditional lecture content into collaborative small group learning and peer-teaching experiences. Students are divided into groups that complete instructor-prescribed activities on a shared Google Slide deck, and then teach the class what they learned. This technique can be used to explore a range of topics including science and non-science content and is particularly amenable to self-contained, related mini-research topics (i.e. the lowest level of organization on the outline of a lecture). This innovative technique was inspired primarily by the Jigsaw technique. However, it is distinct in that it deliberately builds technology skills and includes a class-level presentation. It is recommended for any higher education classroom across disciplines.
Rising antibiotic resistance among Escherichia coli, the leading cause of urinary tract infections (UTIs), has placed a new focus on molecular pathogenesis studies, aiming to identify new therapeutic ...targets. Anti-virulence agents are attractive as chemotherapeutics to attenuate an organism during disease but not necessarily during benign commensalism, thus decreasing the stress on beneficial microbial communities and lessening the emergence of resistance. We and others have demonstrated that the K antigen capsule of E. coli is a preeminent virulence determinant during UTI and more invasive diseases. Components of assembly and export are highly conserved among the major K antigen capsular types associated with UTI-causing E. coli and are distinct from the capsule biogenesis machinery of many commensal E. coli, making these attractive therapeutic targets. We conducted a screen for anti-capsular small molecules and identified an agent designated "C7" that blocks the production of K1 and K5 capsules, unrelated polysaccharide types among the Group 2-3 capsules. Herein lies proof-of-concept that this screen may be implemented with larger chemical libraries to identify second-generation small-molecule inhibitors of capsule biogenesis. These inhibitors will lead to a better understanding of capsule biogenesis and may represent a new class of therapeutics.
Metagenomics is a tool that enables researchers to study genetic material recovered directly from microbial communities or microbiomes. Fueled by advances in sequencing technologies, bioinformatics ...tools, and sample processing, metagenomics studies promise to expand our understanding of human health and the use of microorganisms for agriculture and industry. Therefore, teaching students about metagenomics is crucial to prepare them for modern careers in the life sciences. However, the increasing number of different approaches makes teaching metagenomics to students a challenge. This 8‐week metagenomics laboratory course has the objective of introducing upper‐level undergraduate and graduate students to strategies for designing, executing, and analyzing microbiome investigations. The laboratory component begins with sample processing, library preparation, and submission for high‐throughput sequencing before transitioning to computer‐based activities, which include an introduction to several fundamental computational metagenomics tools. Students analyze their sequencing results and deposit findings in sequence databases. The laboratory component is complemented by a weekly lecture, where active learning sessions promote retrieval practice and allow students to reflect on and diagram processes performed in the laboratory. Attainment of student learning outcomes was assessed through the completion of various course assignments: laboratory reports, presentations, and a cumulative final exam. Further, students' perceptions of their gains relevant to the learning outcomes were evaluated using pre‐ and postcourse surveys. Collectively, these data demonstrate that this course results in the attainment of the learning outcomes and that this approach provides an adaptable way to expose students to the cutting‐edge field of metagenomics.
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