Moving a Journal Article-Based Upper-Level Microbiology Dry Lab from In-Person to Online Instruction.

During the spring semester of 2020, a journal article-based upper-level microbiology laboratory course was offered through Western New Mexico University at Glendale Community College in Glendale, AZ. Because most of the students had taken a lower-level microbiology class with a traditional wet laboratory, a dry lab format was used instead. In the first period of each 2-week cycle, a microbiology article selected by the instructor from the primary literature was discussed using a PowerPoint presentation and a detailed study sheet.

Genomic sequencing of Gracilibacillus dipsosauri reveals key properties of a salt-tolerant α-amylase.

Gracilibacillus dipsosauri is a moderately-halophilic Gram-positive bacterium which forms an extracellular α-amylase that is induced by starch, repressed by D-glucose, and active in 2.0 M KCl. Previous studies showed that while enzyme activity could be measured with the synthetic substrate 2-chloro-4-nitrophenyl-α-D-maltotrioside (CNPG3), other assays were inconsistent and the protein showed aberrant mobility during nondenaturing gel electrophoresis.

Inhibition of urease activity in the urinary tract pathogens Staphylococcus saprophyticus and Proteus mirabilis by dimethylsulfoxide (DMSO).

Aims: Urease is a virulence factor for the urinary tract pathogens Staphylococcus saprophyticus and Proteus mirabilis. Dimethylsulfoxide (DMSO) is structurally similar to urea, used as a solvent for urease inhibitors, and an effective treatment for interstitial cystitis/bladder pain syndrome (IC/BPS). The aims of this study were to test DMSO as a urease inhibitor and determine its physiological effects on S.

Biochemistry laboratory reports: Filling in the introduction and discussion.

Laboratory reports written in the style of a standard scientific article are commonly used to assess student learning in biochemistry laboratory courses. While most students can complete the Materials and Methods or Results sections successfully, many have difficulty with the Introduction and Discussion. They fail to place their data in a larger experimental context or to compare their results to those previously published.

L-Proline catabolism by the high G + C Gram-positive bacterium Paenarthrobacter aurescens strain TC1.

Paenarthrobacter aurescens (formerly called Arthrobacter aurescens) strain TC1 is a high G + C Gram-positive aerobic bacterium that can degrade the herbicide atrazine. Analysis of its genome indicated strain TC1 has the potential to form a bifunctional PutA protein containing L-proline dehydrogenase and L-glutamate-γ-semialdehyde dehydrogenase (L-Δ-pyrroline-5-carboxylate dehydrogenase) activities. P.

Browning in apples: Exploring the biochemical basis of an easily-observable phenotype.

Many fruits and vegetables undergo browning when they are cut and the tissue is exposed to the air. This is due to the activity of the enzyme polyphenol oxidase (PPO, EC 1.14.

Analysis of strains lacking known osmolyte accumulation mechanisms reveals contributions of osmolytes and transporters to protection against abiotic stress.

Osmolyte accumulation and release can protect cells from abiotic stresses. In Escherichia coli, known mechanisms mediate osmotic stress-induced accumulation of K(+) glutamate, trehalose, or zwitterions like glycine betaine. Previous observations suggested that additional osmolyte accumulation mechanisms (OAMs) exist and their impacts may be abiotic stress specific.

L-Malate dehydrogenase activity in the reductive arm of the incomplete citric acid cycle of Nitrosomonas europaea.

The autotrophic nitrifying bacterium Nitrosomonas europaea does not synthesize 2-oxoglutarate (α-ketoglutarate) dehydrogenase under aerobic conditions and so has an incomplete citric acid cycle. L-malate (S-malate) dehydrogenase (MDH) from N. europaea was predicted to show similarity to the NADP(+)-dependent enzymes from chloroplasts and was separated from the NAD(+)-dependent proteins from most other bacteria or mitochondria.

L-Proline nutrition and catabolism in Staphylococcus saprophyticus.

Staphylococcus saprophyticus strains ATCC 15305, ATCC 35552, and ATCC 49907 were found to require L-proline but not L-arginine for growth in a defined culture medium. All three strains could utilize L-ornithine as a proline source and contained L-ornithine aminotransferase and Δ(1)-pyrroline-5-carboxylate reductase activities; strains ATCC 35552 and ATCC 49907 could use L-arginine as a proline source and had L-arginase activity. The proline requirement also could be met by L-prolinamide, L-proline methyl ester, and the dipeptides L-alanyl-L-proline and L-leucyl-L-proline.

Oxidation of 3,4-dehydro-D-proline and other D-amino acid analogues by D-alanine dehydrogenase from Escherichia coli.

3,4-Dehydro-DL-proline is a toxic analogue of L-proline which has been useful in studying the uptake and metabolism of this key amino acid. When membrane fractions from Escherichia coli strain UMM5 (putA1::Tn5 proC24) lacking both L-proline dehydrogenase and L-Delta(1)-pyrroline-5-carboxylate reductase were incubated with 3,4-dehydro-DL-proline, pyrrole-2-carboxylate was formed. There was no enzyme activity with 3,4-dehydro-L-proline, but activity was restored after racemization of the substrate.