Teaching molecular techniques at home: Molecular biology labs that can be performed anywhere and enable hands-on learning of restriction digestion/ligation and DNA amplification.

COVID 19 has changed about every aspect of life including how we teach in higher education. Laboratory experiments vital for learning hands-on techniques are limited due to social distancing requirements and increased numbers of distance-learning students. The solution to loss of hands-on activities has been to compensate with virtual laboratory modules.

Unraveling the role of the enigmatic MatK maturase in chloroplast group IIA intron excision.

Maturases are prokaryotic enzymes that aid self-excision of introns in precursor RNAs and have evolutionary ties to the nuclear spliceosome. Both the mitochondria and chloroplast, due to their prokaryotic origin, encode a single intron maturase, MatR for the mitochondria and MatK for the chloroplast. MatK is proposed to aid excision of seven different chloroplast group IIA introns that reside within precursor RNAs for essential elements of chloroplast function.

Alternative translation initiation codons for the plastid maturase MatK: unraveling the pseudogene misconception in the Orchidaceae.

Background: The plastid maturase MatK has been implicated as a possible model for the evolutionary "missing link" between prokaryotic and eukaryotic splicing machinery. This evolutionary implication has sparked investigations concerning the function of this unusual maturase. Intron targets of MatK activity suggest that this is an essential enzyme for plastid function.

Alterations in the mitochondrial alternative NAD(P)H Dehydrogenase NDB4 lead to changes in mitochondrial electron transport chain composition, plant growth and response to oxidative stress.

The branched respiratory electron transport chain of plants contains a non-phosphorylating alternative pathway consisting of type II NAD(P)H dehydrogenases on both sides of the inner membrane linked through the ubiquinone pool to an alternative oxidase (AOX). T-DNA and RNA interference (RNAi) were used to reduce gene expression to characterize the external NAD(P)H dehydrogenase NDB4 in Arabidopsis. The ndb4 lines showed different levels of suppression of NDB4 protein, leading to increases in NBD2 and AOX1a mRNA and protein levels in all lines.

Phospholipase D family interactions with the cytoskeleton: isoform delta promotes plasma membrane anchoring of cortical microtubules.

Phospholipase D (PLD) is a key enzyme in signal transduction - mediating plant responses to various environmental stresses including drought and salinity. Isotype PLDδ interacts with the microtubule cytoskeleton, although it is unclear if, or how, each of the 12 PLD isotypes in Arabidopsis may be involved mechanistically. We employed RNA interference in epidermal cells of Allium porrum L.

Type II NAD(P)H dehydrogenases are targeted to mitochondria and chloroplasts or peroxisomes in Arabidopsis thaliana.

We found that four type II NAD(P)H dehydrogenases (ND) in Arabidopsis are targeted to two locations in the cell; NDC1 was targeted to mitochondria and chloroplasts, while NDA1, NDA2 and NDB1 were targeted to mitochondria and peroxisomes. Targeting of NDC1 to chloroplasts as well as mitochondria was shown using in vitro and in vivo uptake assays and dual targeting of NDC1 to plastids relies on regions in the mature part of the protein. Accumulation of NDA type dehydrogenases to peroxisomes and mitochondria was confirmed using Western blot analysis on highly purified organelle fractions.

Dynamic changes in the mitochondrial electron transport chain underpinning cold acclimation of leaf respiration.

We examined the effect of short- and long-term changes in temperature on gene expression, protein abundance, and the activity of the alternative oxidase and cytochrome oxidase pathways (AOP and COP, respectively) in Arabidopsis thaliana. The AOP was more sensitive to short-term changes in temperature than the COP, with partitioning to the AOP decreasing significantly below a threshold temperature of 20 degrees C. AOP activity was increased in leaves, which had been shifted to the cold for several days, but this response was transient, with AOP activity subsiding (and COP activity increasing) following the development of leaves in the cold.

Evaluating evolutionary constraint on the rapidly evolving gene matK using protein composition.

The rapidly evolving chloroplast matK gene has nucleotide and amino acid substitution rates suggestive of progression toward a pseudogene state. However, molecular evidence has demonstrated that matK is expressed and functional. We explore in this paper the underlying factors behind the mode and tempo of matK evolution that allow this protein coding gene to accommodate such elevated rates of substitution and yet maintain functionality.

Expression of matK: functional and evolutionary implications.

Strong phylogenetic signal from matK has rendered it an invaluable gene in plant systematic and evolutionary studies at various evolutionary depths. Further, matK is proposed as the only chloroplast-encoded group II intron maturase, thus implicating MATK in chloroplast posttranscriptional processing. For a protein-coding gene, matK has an unusual evolutionary mode and tempo, including relatively high substitution rates at both the nucleotide and amino acids levels.