Algae World: Phycological Research

Image: Psammodictyon sp.

The family Bacillariaceae has been a focus of our interest since David Mann's PhD studies (1974–8), supervised by Frank Round (University of Bristol), which took advantage of a then relatively new technology, scanning electron microscopy. Since the early 2000s, another new technology – Sanger sequencing of DNA – has become highly affordable and widespread, and we have been taking advantage of this to reexamine relationships and classifications within the family.

Here we provide images to support and voucher an extensive molecular phylogenetic analysis of the Bacillariaceae that used datasets for five genes: nuclear SSU and LSU, chloroplast rbcL and psbC, and mitochondrial cox1. Each file of images documents the ultrastructure of one of the clones sequenced.

Clones are listed in alphabetical order of the clone name. The TCC clones were isolated for the Thonon Culture Collection curated by Dr Frédéric Rimet and the SZCZ clones form part of the Szczcecin University culture collection, headed by Prof. Dr. Andrzej Witkowski. Most of the remainder of the clones were isolated in the Royal Botanic Garden Edinburgh or at the Institute for Food and Agricultural Research and Technology, Sant Carles de La Ràpita, Catalonia, Spain, by the authors of the article mentioned below or by Dr Laia Rovira. Clone BA14 was kindly supplied by Dr F. Pniewski; CCMP558 is a clone isolated in the 1950s by J.C. & R.A. Lewin); the KSA clones were part of the University of Texas collections; and Belgium2 was isolated in Ghent by Dr Victor Chepurnov. Light microscope photographs of the BC (= UK barcode) clones are available online in Zenodo, in "Photos of the barcoded strains from the UK-Barcoding" version 2 (https://zenodo.org/record/2549419).

The original SEM images of all clones except the KSA and SZCZ series are held by the Royal Botanic Garden Edinburgh (RBGE). The SEM work for these images was done by Rosa Trobajo and David Mann, mostly using the Leo Supra Field Emission SEM at RBGE (usually operated at 5 kV and a working distance of c. 4 mm; specimens coated with Pt). For their presentation here, we have watermarked the originals and combined them into a single pdf for each clone. The images have not been resized, nor have they been altered in contrast, brightness or sharpness using image processing programs (e.g. Adobe Photoshop, ImageJ). If it is necessary to refer to individual images in the sets, this can be done via the image filename given in the data strip at the bottom. For example, within the set of images for clone BAC901CAT, individual images are Bac901CAT_01, Bac901CAT_02, etc. Please acknowledge these images (with the url) if you refer to them in your publications and refer also to the parent article listed below.

Reference: Mann, D.G., Trobajo, R., Sato, S., Li, C., Witkowski, A., Rimet, F., Ashworth, M.P., Hollands, R.M & Theriot, E.C. (2020). Ripe for reassessment:a synthesis of available molecular data for the speciose diatom family Bacillariaceae. Molecular Phylogenetics and Evolution