The COVID Crisis in Legal Education

This report examines the impact of the COVID disruption on law students and legal education.  Data draw from the responses of over 13,000 law students at 61 law schools that participated in LSSSE in 2021.  The Report also features results from two new LSSSE Modules: The Coping with COVID module, which gathered responses from 1,521 law students and the Experiences with Online Learning module, which highlights responses from 3,450 law students.The report shows that though the core of legal education remained relatively stable and overall satisfaction remained remarkably high, law students were more likely than in years past to be lonely, emotionally exhausted, and to struggle with anxiety and depression.  Furthermore, COVID also deepened ongoing disparities and inequities in legal education.  Vulnerable student populations faced even greater challenges over the past year

Omics-driven identification and elimination of valerolactam catabolism in Pseudomonas putida KT2440 for increased product titer.

Pseudomonas putida is a promising bacterial chassis for metabolic engineering given its ability to metabolize a wide array of carbon sources, especially aromatic compounds derived from lignin. However, this omnivorous metabolism can also be a hindrance when it can naturally metabolize products produced from engineered pathways. Herein we show that P. putida is able to use valerolactam as a sole carbon source, as well as degrade caprolactam. Lactams represent important nylon precursors, and are produced in quantities exceeding one million tons per year (Zhang et al., 2017). To better understand this metabolism we use a combination of Random Barcode Transposon Sequencing (RB-TnSeq) and shotgun proteomics to identify the oplBA locus as the likely responsible amide hydrolase that initiates valerolactam catabolism. Deletion of the oplBA genes prevented P. putida from growing on valerolactam, prevented the degradation of valerolactam in rich media, and dramatically reduced caprolactam degradation under the same conditions. Deletion of oplBA, as well as pathways that compete for precursors L-lysine or 5-aminovalerate, increased the titer of valerolactam from undetectable after 48 h of production to ~90 mg/L. This work may serve as a template to rapidly eliminate undesirable metabolism in non-model hosts in future metabolic engineering efforts

Omics-driven identification and elimination of valerolactam catabolism in Pseudomonas putida KT2440 for increased product titer.

Pseudomonas putida is a promising bacterial chassis for metabolic engineering given its ability to metabolize a wide array of carbon sources, especially aromatic compounds derived from lignin. However, this omnivorous metabolism can also be a hindrance when it can naturally metabolize products produced from engineered pathways. Herein we show that P. putida is able to use valerolactam as a sole carbon source, as well as degrade caprolactam. Lactams represent important nylon precursors, and are produced in quantities exceeding one million tons per year (Zhang et al., 2017). To better understand this metabolism we use a combination of Random Barcode Transposon Sequencing (RB-TnSeq) and shotgun proteomics to identify the oplBA locus as the likely responsible amide hydrolase that initiates valerolactam catabolism. Deletion of the oplBA genes prevented P. putida from growing on valerolactam, prevented the degradation of valerolactam in rich media, and dramatically reduced caprolactam degradation under the same conditions. Deletion of oplBA, as well as pathways that compete for precursors L-lysine or 5-aminovalerate, increased the titer of valerolactam from undetectable after 48 h of production to ~90 mg/L. This work may serve as a template to rapidly eliminate undesirable metabolism in non-model hosts in future metabolic engineering efforts

Massively parallel fitness profiling reveals multiple novel enzymes in Pseudomonas putida lysine metabolism

P. putida lysine metabolism can produce multiple commodity chemicals, conferring great biotechnological value. Despite much research, the connection of lysine catabolism to central metabolism in P. putida remained undefined. Here, we used random barcode transposon sequencing to fill the gaps of lysine metabolism in P. putida. We describe a route of 2-oxoadipate (2OA) catabolism, which utilizes DUF1338-containing protein P. putida 5260 (PP_5260) in bacteria. Despite its prevalence in many domains of life, DUF1338-containing proteins have had no known biochemical function. We demonstrate that PP_5260 is a metalloenzyme which catalyzes an unusual route of decarboxylation of 2OA to d-2-hydroxyglutarate (d-2HG). Our screen also identified a recently described novel glutarate metabolic pathway. We validate previous results and expand the understanding of glutarate hydroxylase CsiD by showing that can it use either 2OA or 2KG as a cosubstrate. Our work demonstrated that biological novelty can be rapidly identified using unbiased experimental genetics and that RB-TnSeq can be used to rapidly validate previous results.Despite intensive study for 50 years, the biochemical and genetic links between lysine metabolism and central metabolism in Pseudomonas putida remain unresolved. To establish these biochemical links, we leveraged random barcode transposon sequencing (RB-TnSeq), a genome-wide assay measuring the fitness of thousands of genes in parallel, to identify multiple novel enzymes in both l- and d-lysine metabolism. We first describe three pathway enzymes that catabolize l-2-aminoadipate (l-2AA) to 2-ketoglutarate (2KG), connecting d-lysine to the TCA cycle. One of these enzymes, P. putida 5260 (PP_5260), contains a DUF1338 domain, representing a family with no previously described biological function. Our work also identified the recently described coenzyme A (CoA)-independent route of l-lysine degradation that results in metabolization to succinate. We expanded on previous findings by demonstrating that glutarate hydroxylase CsiD is promiscuous in its 2-oxoacid selectivity. Proteomics of selected pathway enzymes revealed that expression of catabolic genes is highly sensitive to the presence of particular pathway metabolites, implying intensive local and global regulation. This work demonstrated the utility of RB-TnSeq for discovering novel metabolic pathways in even well-studied bacteria, as well as its utility a powerful tool for validating previous research

Chemistry Collection Development Policy

The chemistry collection exists to support the teaching, research, and service endeavors of the Department of Chemistry and the University of Nebraska-Lincoln community. The public may benefit from the chemistry collection, although specific materials are not collected to meet their needs. Chemistry-related materials not available in the library’s collection are generally readily available through Interlibrary Loan. The collection is focused on QD Library of Congress call number range, although the heavily interdisciplinary nature of scientific study necessitates some overlap with other Q call number ranges, R, S, T, and other areas

Biological Sciences Collection Development Policy

The biological sciences collection exists to support the teaching, research, and service functions of the School of Biological Sciences and the University of Nebraska-Lincoln community. The public may benefit from the biological sciences collection, although specific materials are not collected to meet their needs. Biology-related materials not available in the library’s collection are generally readily available through Interlibrary Loan. The collection is focused on the biologically-based subsections of the Q Library of Congress call number range, although the heavily interdisciplinary nature of scientific study necessitates some overlap with R, S, T, and other areas

Diversity in the structure of signals produced by South American weakly electric knifefish

Natural and sexual selection shape animal communication signals according to the demands of social context and the environment, which results in enormous variation in signal properties. My dissertation uses the electrocommunication signals of South American weakly electric knifefish to compare signal structure across several closely related species, with particular emphasis on signals that are extreme or unusual. Weakly electric fish continuously generate an electric field using an electric organ discharge (EOD). During short-range social interactions, fish produce chirps by rapidly and transiently increasing EOD frequency. I used recordings with playbacks of conspecific signals and hormone manipulation to characterize the sexually dimorphic chirp duration of Parapteronotus hasemani, a species of electric fish with high-frequency, long-duration chirps and huge variation in male morphology. I also described signaling behavior in Distocyclus conirostris , a species of electric fish with a low-frequency EOD and an unusual asymmetrical behavioral response to “jamming” created when EODs of similar frequencies interact. Next, I compared across species to examine how signal properties (EODs and chirping) interact to influence each other’s detection and evolution. Certain signal parameters such as chirp frequency modulation and EOD frequency difference have substantial effects on chirp conspicuousness. Contrary to expectations, there was little support for a strict co-evolution in which a species’ chirps are most conspicuous on their own EOD waveforms. Thus, although EOD properties influence chirp conspicuousness, other factors such as the social or physical environment also likely shape chirp structure. Additionally, I show that EOD waveform may differ in perceptibility based on the EOD waveform complexity of the interacting fish. I consider how chirp conspicuousness could drive the evolution of sexually dimorphic chirps (such as those produced by P. hasemani), and I raise questions about whether low-frequency EODs (such as those produced by D. conirostris) contain sufficient information for fish to detect conspecific EOD frequencies using the neural mechanisms described in fish with high-frequency EODs. Taken together, these results show how the properties of multi-component signals shape each other and impact signal detectability. Finally, my dissertation concludes with a description of an innovative approach to teaching scientific communication skills in a highly structured undergraduate introductory biology lab

Chirping and asymmetric jamming avoidance responses in the electric fish Distocyclus conirostris

Electrosensory systems of weakly electric fish must accommodate competing demands of sensing the environment (electrolocation) and receiving social information (electrocommunication). The jamming avoidance response (JAR) is a behavioral strategy thought to reduce electrosensory interference from conspecific signals close in frequency. We used playback experiments to characterize electric organ discharge frequency (EODf), chirping behavior and the JAR of Distocyclus conirostris, a gregarious electric fish species. EODs of D. conirostris had low frequencies (∼80-200 Hz) that shifted in response to playback stimuli. Fish consistently lowered EODf in response to higher-frequency stimuli but inconsistently raised or lowered EODf in response to lower-frequency stimuli. This led to jamming avoidance or anti-jamming avoidance, respectively. We compare these behaviors with those of closely related electric fish (Eigenmannia and Sternopygus) and suggest that the JAR may have additional social functions and may not solely minimize the deleterious effects of jamming, as its name suggests. © 2018. Published by The Company of Biologists Ltd | Journal of Experimental Biology