Marsay, K. | Search bioRxiv

bioRxiv2021

High-resolution screening for marine prokaryotic and eukaryotic taxa with selective preference for PE and PET surfaces

Marine plastic debris serve as substrates for the colonization of a variety of prokaryote and eukaryote organisms. Of particular interest are the microorganisms that have adapted to thrive on plastic as they may contain genes, enzymes or pathways involved in the colonization or metabolism of plastics. We implemented DNA metabarcoding with nanopore MinION sequencing to compare the one-month-old biomes of hydrolysable (polyethylene terephthalate) and non-hydrolysable (polyethylene) plastics surfaces vs. those of glass and the surrounding water in a Mediterranean Sea marina. We sequenced longer 16S rRNA, 18S rRNA and ITS barcode loci for a more comprehensive taxonomic profiling of the bacterial, protist and fungal communities respectively. Long read sequencing enabled high-resolution mapping to genera and species. Using differential abundance screening we identified 32 bacteria and five eukaryotic species, that were differentially abundant on plastic compared to glass. This approach may be used in the future to characterize the plastisphere communities and to screen for microorganisms with a plastic-metabolism potential.

microbiology↗

bioRxiv2021

Tetraspanin Cd9b plays a role in fertility in zebrafish

In mice, CD9 expression on the egg is required for efficient sperm-egg fusion and no effects on ovulation or male fertility are observed in CD9 null animals. Here we show that cd9b KO zebrafish also appear to have fertility defects. In contrast to mice, fewer eggs were laid by cd9b KO zebrafish pairs and, of the eggs laid, a lower percentage were fertilised. In vitro fertilization (IVF) was used to demonstrate that factors such as courting behaviour, adult size and mate choice were not causing the unexpected decrease in clutch size. The decrease in egg numbers could be rescued by exchanging either cd9b KO partner, male or female, for a wildtype (WT) partner. However, the fertilisation defect could only be rescued by crossing a cd9b KO female with a WT male. Our results indicate that Cd9b has several roles in fish fertility, affecting both clutch size and egg fertilisation. HighlightsO_LIcd9b mutant pairs lay fewer eggs and of the eggs laid, fewer are fertilised. C_LIO_LIMutation in cd9b does not affect primordial germ cell number or migration. C_LIO_LIReduction in number of eggs and fertility is not due to courting behaviour, fish size or mate choice. C_LIO_LIcd9b mutation in either gender affects the number of eggs laid. C_LIO_LIMutation of cd9b in the males affects fertilisation efficiency but mutation of cd9b in the females does not. C_LI

developmental biology↗