Author's posts

Analysis of diverse eukaryotes suggests the existence of an ancestral mitochondrial apparatus derived from the bacterial type II secretion system

Nat Commun. 2021 May 19;12(1):2947. doi: 10.1038/s41467-021-23046-7. ABSTRACT The type 2 secretion system (T2SS) is present in some Gram-negative eubacteria and used to secrete proteins across the outer membrane. Here we report that certain representative heteroloboseans, jakobids, malawimonads and hemimastigotes unexpectedly possess homologues of core T2SS components. We show that at least some of them …

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Identifying biases and their potential solutions in human microbiome studies

Microbiome. 2021 May 18;9(1):113. doi: 10.1186/s40168-021-01059-0. ABSTRACT Advances in DNA sequencing technology have vastly improved the ability of researchers to explore the microbial inhabitants of the human body. Unfortunately, while these studies have uncovered the importance of these microbial communities to our health, they often do not result in similar findings. One possible reason for …

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Treasurer’s Report for Financial Year (FY) 2019

Mol Biol Evol. 2021 May 3:msab012. doi: 10.1093/molbev/msab012. Online ahead of print. NO ABSTRACT PMID:34009329 | DOI:10.1093/molbev/msab012

Genomic variation of an endosymbiotic dinoflagellate (Symbiodinium ‘fitti’) among closely related coral hosts

Mutualisms where hosts are coupled metabolically to their symbionts often exhibit high partner fidelity. Most reef-building coral species form obligate symbioses with a specific species of photosymbionts, dinoflagellates in the family Symbiodiniaceae, despite needing to acquire symbionts early in their development from environmental sources. Three Caribbean acroporids (Acropora palmata, A. cervicornis, and their F1 hybrid) are sympatric across much of their range, but often occupy different…

Maricaulis alexandrii sp. nov., a novel active bioflocculants-bearing and dimorphic prosthecate bacterium isolated from marine phycosphere

An aerobic, Gram-stain-negative, straight or curved rods and dimorphic prosthecate bacterium designated as strain LZ-16-1^(T) was isolated from phycosphere microbiota of routinely laboratory-cultured and highly-toxic marine dinoflagellate Alexandrium catenella LZT09. Strain LZ-16-1^(T) produces active bioflocculanting exopolysaccharides (EPS). Cells were dimorphic with non-motile prostheca, or non-stalked and motile by a single polar flagellum. Growth occurred at 10-40 °C, pH 5-9 and 1-8% (w/v)…

Maricaulis alexandrii sp. nov., a novel active bioflocculants-bearing and dimorphic prosthecate bacterium isolated from marine phycosphere

An aerobic, Gram-stain-negative, straight or curved rods and dimorphic prosthecate bacterium designated as strain LZ-16-1^(T) was isolated from phycosphere microbiota of routinely laboratory-cultured and highly-toxic marine dinoflagellate Alexandrium catenella LZT09. Strain LZ-16-1^(T) produces active bioflocculanting exopolysaccharides (EPS). Cells were dimorphic with non-motile prostheca, or non-stalked and motile by a single polar flagellum. Growth occurred at 10-40 °C, pH 5-9 and 1-8% (w/v)…

An in vivo genome-wide shRNA screen identifies BCL6 as a targetable biomarker of paclitaxel resistance in breast cancer

Mol Oncol. 2021 May 1. doi: 10.1002/1878-0261.12964. Online ahead of print. ABSTRACT Paclitaxel is a common breast cancer drug; however, some tumors are resistant. The identification of biomarkers for paclitaxel resistance or sensitivity would enable the development of strategies to improve treatment efficacy. A genome-wide in vivo shRNA screen was performed on paclitaxel-treated mice with …

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Genetic and spatial organization of the unusual chromosomes of the dinoflagellate Symbiodinium microadriaticum

Dinoflagellates are main primary producers in the oceans, the cause of algal blooms and endosymbionts of marine invertebrates. Much remains to be understood about their biology, including their peculiar crystalline chromosomes. We assembled 94 chromosome-scale scaffolds of the genome of the coral endosymbiont Symbiodinium microadriaticum and analyzed their organization. Genes are enriched towards the ends of chromosomes and are arranged in alternating unidirectional blocks. Some chromosomes are…

Transcription-dependent domain-scale three-dimensional genome organization in the dinoflagellate Breviolum minutum

Dinoflagellate chromosomes represent a unique evolutionary experiment, as they exist in a permanently condensed, liquid crystalline state; are not packaged by histones; and contain genes organized into tandem gene arrays, with minimal transcriptional regulation. We analyze the three-dimensional genome of Breviolum minutum, and find large topological domains (dinoflagellate topologically associating domains, which we term ‘dinoTADs’) without chromatin loops, which are demarcated by convergent…

A novel fragmented mitochondrial genome in the protist pathogen Toxoplasma gondii and related tissue coccidia

Mitochondrial genome content and structure vary widely across the eukaryotic tree of life, with protists displaying extreme examples. Apicomplexan and dinoflagellate protists have evolved highly reduced mitochondrial genome sequences, mtDNA, consisting of only three cytochrome genes and fragmented rRNA genes. Here, we report the independent evolution of fragmented cytochrome genes in Toxoplasma and related tissue coccidia and evolution of a novel genome architecture consisting minimally of 21…