Vacuolar ion channels: Roles in plant nutrition and signalling

Vacuoles play various roles in many physiologically relevant processes in plants. Some of the more prominent are turgor provision, the storage of minerals and nutrients, and cellular signalling. To fulfil these functions a complement of membrane transporters is present at the tonoplast. Prolific patch clamp studies have shown that amongst these, both selective and non-selective ion channels participate in turgor regulation, nutrient storage and signalling. This article reviews the physiological roles, expression patterns and structure function properties of plant vacuolar anion and cation channels that are gated by voltage and ligands.     

Fostering equity,diversity, and inclusion in large,first‐year classes: Using reflective practice questions to promote universal design for learning in ecology and evolution lessons

Instructors can deliberately design for equity, diversity, and inclusion, including for large first‐year classes, and now instructors have added challenges given COVID‐19. Our paper explores the question: How do we integrate equity, diversity, and inclusion and universal design for learning (UDL) into first‐year, undergraduate ecology and evolution introductory lessons given the COVID‐19 pandemic? Given the large field exploring equity, diversity, and inclusion, we chose to focus on developing reflective practice question rubrics for before, during, and after lessons to encourage UDL for instructors, teaching assistants, and learners. We conducted a focus group within our team and discussed ideas related to online learning, including related pitfalls and solutions. Lastly, we created a figure to illustrate ideas and end with a general discussion. Our reflective practice questions for UDL rubrics, figure, focus group, and discussion aim to increase positive action for equity, diversity, and inclusion in the classroom and beyond.     

miR-25 alleviates polyQ-mediated cytotoxicity by silencing ATXN3

MicroRNAs (miRNAs) have been reported to play significant roles in the pathogenesis of various polyQ diseases. This study aims to investigate the regulation of ATXN3 gene expression by miRNA. We found that miR-25 reduced both wild-type and polyQ-expanded mutant ataxin-3 protein levels by interacting with the 3′UTR of ATXN3 mRNA. miR-25 also increased cell viability, decreased early apoptosis, and downregulated the accumulation of mutant ataxin-3 protein aggregates in SCA3/MJD cells. These novel results shed light on the potential role of miR-25 in the pathogenesis of SCA3/MJD, and provide a possible therapeutic intervention for this disorder.     

NAD+ boosting reduces age-associated amyloidosis and restores mitochondrial homeostasis in muscle

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THE EFFECT OF BIASED INCLUSION OF TAXA ON THE CORRELATION BETWEEN DISCRETE CHARACTERS IN PHYLOGENETIC TREES

In a published paper, a method for testing the correlation between two discrete characters was presented and applied to test whether in butterfly larvae origins of gregariousness are concentrated to lineages with aposematic coloration. The relationship was found to be nonsignificant. However, the butterfly data on which the test was applied had been compiled in another study to investigate evolutionary sequences and was biased, because there was an overrepresentation of aposematic, as compared to cryptic, branches in the sample. In the paper presented here, aposematic and cryptic clades of the original phylogeny were resolved to the same degree, and the resulting set of branches may be regarded as unbiased with respect to the hypothesis being tested. A method for testing the contingency of states in two characters was then applied to the new data set, resulting in a highly significant relationship between origins of gregariousness and aposematic coloration. I argue that when using statistical methods on phylogenetic data, it is crucial to resolve various parts of the phylogeny to the same comparable systematic unit in order not to get a distorted sample of taxa/branches.     

Mass spectrometry investigation of glycosylation on the NXS/T sites in recombinant glycoproteins

We used a targeted proteomics approach to investigate whether introduction of new N-linked glycosylation sites in a chimeric protein influence the glycosylation of the existing glycosylation sites. To accomplish our goals, we over-expressed and purified a chimeric construct that contained the Fc region of the IgG fused to the exons 7 & 8 of mouse ZP3 (IgG-Fc-ZP3E7 protein). Immunoglobulin heavy chain (IgG-HC protein) was used as control. We then analyzed the IgG-HC and IgG-Fc-ZP3E7 proteins by liquid chromatography-tandem mass spectrometry (LC–MS/MS) and by Western blotting (WB). We concluded that in control experiments, the glycosylation site was occupied as expected. However, in the IgG-Fc-ZP3E7 protein, we concluded that only one out of three NXS/T glycosylation sites is occupied by N-linked oligosaccharides. We also concluded that in the IgG-Fc-ZP3E7 protein, upon introduction of additional potential NXS/T glycosylation sites within its sequence, the original NST/S glycosylation site from the Fc region of the IgG-Fc-ZP3E7 protein is no longer glycosylated. The biomedical significance of our findings is discussed.     

Lectin activity of Bacillus thuringiensis parasporal inclusion proteins

Parasporal inclusion proteins from a total of 151 Bacillus thuringiensis strains, consisting of 139 Japanese isolates and the type strains of 12 H serovars, were screened for haemagglutination (HA) activity against sheep erythrocytes. Of 58 B. thuringiensis strains with HA activity, nine strains exhibited high activity and the remaining 49 strains were moderately active. The strains with high HA activity were derived from phylloplanes and soils of five geographically different localities, and belonged to H serovars kurstaki and other undefined serotype(s). The HA activities in the four selected strains were generated only when alkali-solubilised parasporal inclusion proteins were proteolytically processed. Furthermore, the lectin activity of the four strains was strongly inhibited by preincubation with N-acetylgalactosamine. The lectin-producing B. thuringiensis strains were heterogeneous in other biological activities of parasporal inclusions: insecticidal activity and cytocidal action on human leukaemia T cells.     

An improved method for large-scale purification of recombinant human glucagon

Glucagon was expressed inEscherichia coli as a fusion protein including the glucagon sequence [Ishizakiet al. (1992),Appl. Microbiol. Biotechnol.36, 483–486]. The high-level expression of a protein inE. coli often results in an insoluble aggregate called an inclusion body containing a fusion protein. In our previous report [Yoshikawaet al. (1992),J. Protein Chem. 11, 517–525], we solubilized this inclusion body by using guanidinium chloride. However, the existence of denaturant caused problems such as a low proteolytic activity for transforming the fusion protein into glucagon and complicated purification methods. We tried to improve the method to enable large-scale purification. At alkaline pH, the inclusion body could be solubilized to a high concentration and cleaved by amino acid-specific endopeptidases. By utilizing isoelectric precipitations as a new economical purification method for glucagon from intermediates, the glucagon obtained was shown to be over 99.5% pure by analytical RP-HPLC. The yield was almost equal that of our previous method, and the glucagon produced was chemically and biochemically equivalent to natural glucagon.