Contributions of Andrée Tixier-Vidal (1923-2021) to modern cell biology.

This article illustrates the main stages of the scientific career of Dr Andrée Tixier-Vidal, a pioneer in cell biology research in France. She made important discoveries in the field of hormone secretion and neuronal morphogenesis. She played a key role in developing pituitary and neuronal cultures and using electron microscopy to study cellular structures.

One-locus-several-primers: A strategy to improve the taxonomic and haplotypic coverage in diet metabarcoding studies.

In diet metabarcoding analyses, insufficient taxonomic coverage of PCR primer sets generates false negatives that may dramatically distort biodiversity estimates. In this paper, we investigated the taxonomic coverage and complementarity of three cytochrome oxidase subunit I gene (COI) primer sets based on in silico analyses and we conducted an in vivo evaluation using fecal and spider web samples from different invertivores, environments, and geographic locations. Our results underline the lack of predictability of both the coverage and complementarity of individual primer sets: (a) sharp discrepancies exist observed between in silico and in vivo analyses (to the detriment of in silico analyses); (b) both coverage and complementarity depend greatly on the predator and on the taxonomic level at which preys are considered; (c) primer sets' complementarity is the greatest at fine taxonomic levels (molecular operational taxonomic units [MOTUs] and variants).

Salmo macrostigma (Teleostei, Salmonidae): Nothing more than a brown trout (S. trutta) lineage?

We examined specimens of the macrostigma trout Salmo macrostigma, which refers to big black spots on the flanks, to assess whether it is an example of taxonomic inflation within the brown trout Salmo trutta complex. Using new specimens, publicly available data and a mitogenomic protocol to amplify the control and cytochrome b regions of the mitochondrial genome from degraded museum samples, including one syntype specimen, the present study shows that the macrostigma trout is not a valid species. Our results suggest the occurrence of a distinct evolutionary lineage of S.

Tempo and rates of diversification in the South American cichlid genus Apistogramma (Teleostei: Perciformes: Cichlidae).

Evaluating biodiversity and understanding the processes involved in diversification are noticeable conservation issues in fishes subject to large, sometimes illegal, ornamental trade purposes. Here, the diversity and evolutionary history of the Neotropical dwarf cichlid genus Apistogramma from several South American countries are investigated. Mitochondrial and nuclear markers are used to infer phylogenetic relationships between 31 genetically identified species.

A from-benchtop-to-desktop workflow for validating HTS data and for taxonomic identification in diet metabarcoding studies.

The main objective of this work was to develop and validate a robust and reliable "from-benchtop-to-desktop" metabarcoding workflow to investigate the diet of invertebrate-eaters. We applied our workflow to faecal DNA samples of an invertebrate-eating fish species. A fragment of the cytochrome c oxidase I (COI) gene was amplified by combining two minibarcoding primer sets to maximize the taxonomic coverage.

Phylogeography of the heavily poached African common pangolin (Pholidota, Manis tricuspis) reveals six cryptic lineages as traceable signatures of Pleistocene diversification.

Knowledge on faunal diversification in African rainforests remains scarce. We used phylogeography to assess (i) the role of Pleistocene climatic oscillations in the diversification of the African common pangolin (Manis tricuspis) and (ii) the utility of our multilocus approach for taxonomic delineation and trade tracing of this heavily poached species. We sequenced 101 individuals for two mitochondrial DNA (mtDNA), two nuclear DNA and one Y-borne gene fragments (totalizing 2602 bp).

Morphology and genetics reveal an intriguing pattern of differentiation at a very small geographic scale in a bird species, the forest thrush Turdus lherminieri.

Mobile organisms are expected to show population differentiation only over fairly large geographical distances. However, there is growing evidence of discrepancy between dispersal potential and realized gene flow. Here we report an intriguing pattern of differentiation at a very small spatial scale in the forest thrush (Turdus lherminieri), a bird species endemic to the Lesser Antilles.

The changing pace of insular life: 5000 years of microevolution in the Orkney vole (Microtus arvalis orcadensis).

Island evolution may be expected to involve fast initial morphological divergence followed by stasis. We tested this model using the dental phenotype of modern and ancient common voles (Microtus arvalis), introduced onto the Orkney archipelago (Scotland) from continental Europe some 5000 years ago. First, we investigated phenotypic divergence of Orkney and continental European populations and assessed climatic influences.

New light on the evolutionary history of the common goby (Pomatoschistus microps) with an emphasis on colonization processes in the Mediterranean Sea.

Through the study of the phylogeographic structure and demographic history of the common goby, Pomatoschistus microps, the influence of Quaternary climatic changes on the evolutionary history of coastal and marine fishes is investigated. Because of its sedentary life cycle in Mediterranean lagoons, it is also a good model to study more specifically if the formation of lagoons during the Holocene had an impact on population structure and demography. Mitochondrial sequences of Northeastern Atlantic and Western Mediterranean specimens were used for phylogenetic reconstructions as well as divergence time estimates, demographic history and population structure analyses.

Genetic diversity and conservation of the Prespa trout in the Balkans.

The Balkans are known to have a high level of biodiversity and endemism. No less than 15 taxa have been recorded in salmonids of the Salmo genus. Among them, the Prespa trout is found in only four river systems flowing into Lake Macro Prespa, three in the Former Yugoslav Republic of Macedonia and one in Greece.

Responses of wild small mammals to arsenic pollution at a partially remediated mining site in Southern France.

Partial remediation actions at a former gold mine in Southern France led to a mosaic of contaminated and rehabilitated zones. In this study, the distribution of arsenic and its potential adverse effects on small mammals were investigated. The effectiveness of remediation for reducing the transfer of this element into wildlife was also discussed.

New insight into the colonization processes of common voles: inferences from molecular and fossil evidence.

Elucidating the colonization processes associated with Quaternary climatic cycles is important in order to understand the distribution of biodiversity and the evolutionary potential of temperate plant and animal species. In Europe, general evolutionary scenarios have been defined from genetic evidence. Recently, these scenarios have been challenged with genetic as well as fossil data.

Ancient DNA evidence for the loss of a highly divergent brown bear clade during historical times.

The genetic diversity of present-day brown bears (Ursus arctos) has been extensively studied over the years and appears to be geographically structured into five main clades. The question of the past diversity of the species has been recently addressed by ancient DNA studies that concluded to a relative genetic stability over the last 35,000 years. However, the post-last glacial maximum genetic diversity of the species still remains poorly documented, notably in the Old World.

Heterodimerization of endothelin-converting enzyme-1 isoforms regulates the subcellular distribution of this metalloprotease.

Endothelin-converting enzyme (ECE) is a membrane metalloprotease that generates endothelin from its direct precursor big endothelin. Four isoforms of ECE-1 are produced from a single gene through the use of alternate promoters. These isoforms share the same extracellular catalytic domain and contain unique cytosolic tails, which results in their specific subcellular targeting.

Phylogenetic relationships of the five extant Rhinoceros species (Rhinocerotidae, Perissodactyla) based on mitochondrial cytochrome b and 12S rRNA genes.

A major question in rhinocerotid phylogenetics concerns the position of the Sumatran rhinoceros (Dicerorhinus sumatrensis) with regard to the other extant Asian (Rhinoceros unicornis and R. sondaicus) and African (Diceros bicornis and Ceratotherium simum) species. We have examined this particular question through the phylogenetic analysis of the complete sequences of the mitochondrial 12S rRNA and cytochrome b genes.

Expression of the endothelin-converting enzyme-1 isoforms in endothelial cells.

The transformed human endothelial cell line EA.hy926 is commonly used for studying in vitro different aspects of endothelial cell biology such as signal transduction, expression or angiogenesis. These cells have the ability to process big endothelin (big-ET) into endothelin (ET), and express the endothelin-converting enzyme ECE-1.

A fourth isoform of endothelin-converting enzyme (ECE-1) is generated from an additional promoter molecular cloning and characterization.

Human endothelin-converting enzyme (ECE-1) has been shown to exist as three isoforms (ECE-1a, ECE-1b and ECE-1c) diverging in their N-terminal sequence and displaying different patterns of subcellular localization. We report here the cloning of ECE-1d, a novel isoform of 767 amino acids, which is generated from the same gene via the existence of an additional promoter located upstream from the third exon of the ECE-1 gene. ECE-1d converting activity is comparable to that of the other three isoenzymes.

Two di-leucine-based motifs account for the different subcellular localizations of the human endothelin-converting enzyme (ECE-1) isoforms.

Endothelin-converting enzyme (ECE-1) is a type II integral membrane protein which plays a key role in the biosynthetic pathway of the vasoconstricting endothelins. Three ECE-1 isoforms, differing by their N-terminal cytoplasmic tails, are generated from a single gene. When expressed in CHO cells, they display comparable enzymatic activity but whereas ECE-1a is strongly expressed at the cell surface, ECE-1b is exclusively intracellular and ECE-1c presents an intermediate distribution.

Discovery of Homo sp. tooth associated with a mammalian cave fauna of Late Middle Pleistocene age, northern Thailand.

In the context of a Thai-French paleontological project, a single human tooth, a right upper fourth premolar, has been discovered in Northern Thailand among mammalian fossil remains excavated from the "Thum Wiman Nakin" cave. Based on the fauna associated with the human tooth and the Uranium/Thorium datings from the overlying calcite beds, we attribute this site to the Late Middle Pleistocene. The human tooth was compared with teeth of Chinese and Javanese Homo erectus, Homo sapiens neanderthalensis and Homo sapiens sapiens as well as teeth of apes (Orang-utan).

A 21-kDa polypeptide belonging to a new family of proteins is expressed in the Golgi apparatus of neural and germ cells.

We have isolated a full-length murine clone corresponding to the rat neuronal p1A75 partial cDNA (Sutcliffe, J. G., Milner, R.

Aminopeptidase B: a processing enzyme secreted and associated with the plasma membrane of rat pheochromocytoma (PC12) cells.

Aminopeptidase B (Ap-B) is a Zn2+-dependent exopeptidase which selectively removes Arg and/or Lys residues from the N terminus of several peptide substrates. Isolated and characterized from rat testes, this ubiquitous enzyme may participate in the final stages of precursor processing mechanisms. To test this hypothesis, we have investigated the secretion and subcellular localization of this enzyme in a rat cell line of pheochromocytoma (PC12 cells).

Immunocytochemical localization of the prohormone convertases PC1 and PC2 in rat prolactin cells.

The prohormone convertases PC1 and PC2 are subtilisin-related endopeptidases that process prohormone and neuropeptide precursors. Using different ultrastructural immunocytochemical approaches, we have investigated their intracellular distribution in a neuroendocrine cell type that has not been examined thus far, the rat anterior pituitary lactotrope. These cells secrete mainly prolactin and also express the neuroendocrine-specific protein secretogranin II, which is considered a peptide precursor.

Cleavage-secretion of angiotensin I-converting enzyme in yeast.

Angiotensin I-converting enzyme (ACE) is a type I transmembrane protein composed of two domains (N and C domains) which undergoes a post-translational proteolytic cleavage in mammalian cells to release the soluble ectodomain. The protease involved in ACE cleavage-secretion (ACE-secretase) is not well characterised and eludes isolation: the presence of a yeast homologue, thus more amenable to genetic manipulation, would facilitate its identification. We have expressed a secreted form of the ACE C domain, lacking the C-terminal membrane anchor (C domain(deltaCOOH)), and the membrane-anchored C domain (C domain) in the yeast Pichia pastoris by fusion to prepro-alpha-factor.