Immersive virtual reality in STEM: is IVR an effective learning medium and does adding self-explanation after a lesson improve learning outcomes?

The goal of the current study was to investigate the effects of an immersive virtual reality (IVR) science simulation on learning in a higher educational setting, and to assess whether using self-explanation has benefits for knowledge gain. A sample of 79 undergraduate biology students (40 females, 37 males, 2 non-binary) learned about next-generation sequencing using an IVR simulation that lasted approximately 45 min. Students were randomly assigned to one of two instructional conditions: self-explanation (n = 41) or control (n = 38).

Nucleotides, Nucleosides, and Nucleobases.

We review literature on the metabolism of ribo- and deoxyribonucleotides, nucleosides, and nucleobases in Escherichia coli and Salmonella,including biosynthesis, degradation, interconversion, and transport. Emphasis is placed on enzymology and regulation of the pathways, at both the level of gene expression and the control of enzyme activity. The paper begins with an overview of the reactions that form and break the N-glycosyl bond, which binds the nucleobase to the ribosyl moiety in nucleotides and nucleosides, and the enzymes involved in the interconversion of the different phosphorylated states of the nucleotides.

Xanthosine utilization in Salmonella enterica serovar Typhimurium is recovered by a single aspartate-to-glycine substitution in xanthosine phosphorylase.

xapABR from Salmonella enterica was analyzed and compared with the corresponding Escherichia coli genes. xapB and xapR, but not xapA, encode functional proteins. An S.

Escherichia coli purine nucleoside phosphorylase II, the product of the xapA gene.

Purine nucleoside phosphorylases (PNPs, E. C. 2.

Purification and characterization of RihC, a xanthosine-inosine-uridine-adenosine-preferring hydrolase from Salmonella enterica serovar Typhimurium.

Salmonella enterica serovar Typhimurium normally salvage nucleobases and nucleosides by the action of nucleoside phosphorylases and phosphoribosyltransferases. In contrast to Escherichia coli, which catabolizes xanthosine by xanthosine phosphorylase (xapA), Salmonella cannot grow on xanthosine as the sole carbon and energy source. By functional complementation, we have isolated a nucleoside hydrolase (rihC) that can complement a xapA deletion in E.

Regulation of expression of the 2-deoxy-D-ribose utilization regulon, deoQKPX, from Salmonella enterica serovar typhimurium.

Salmonella enterica, in contrast to Escherichia coli K12, can use 2-deoxy-D-ribose as the sole carbon source. The genetic determinants for this capacity in S. enterica serovar Typhimurium include four genes, of which three, deoK, deoP, and deoX, constitute an operon.

A new type of dihydroorotate dehydrogenase, type 1S, from the thermoacidophilic archaeon Sulfolobus solfataricus.

Dihydroorotate dehydrogenase (DHOD) (EC 1.3.3.