Pseudo-nitzschia Peragallo (Bacillariophyceae) diversity and domoic acid accumulation in tuberculate cockles and sweet clams in M’diq Bay, Morocco

The diversity of Pseudo-nitzschia (Bacillariophyceae) and accumulation of the neurotoxin domoic acid (DA) in two types of shellfish; tuberculate cockles (Acanthocardia tuberculata) and sweet clams (Challista chione) was explored in M’diq Bay,Morocco during 2007. The highest abundances of Pseudo-nitzschia were found during the period from March to October, with peaks occurring in May and September. Toxin analysis showed an accumulation of domoic acid in shellfish sampled during spring and autumn. The maximum toxin concentration was 4.9 mg DAg–1 of the whole tissue recorded in sweet clam during spring. Using transmission electron microscopy, thirteen Pseudo-nitzschia species were identified, eight of which are known as producers of domoic acid: P. multistriata, P. cuspidata, P. galaxiae, P. multiseries, P. pseudodelicatissima, P. pungens var. aveirensis, P. calliantha and P. fraudulenta. The five non- toxic species observed were P. subpacifica, P. arenysensis, P. dolorosa, P. subfraudulenta, and P. cf. caciantha

A New Role for SAG12 Cysteine Protease in Roots of Arabidopsis thaliana

Senescence associated gene (SAG) 12, which encodes a cysteine protease is considered to be important in nitrogen (N) allocation to Arabidopsis thaliana seeds. A decrease in the yield and N content of the seeds was observed in the Arabidopsis SAG12 knockout mutants (sag12) relative to the wild type (Col0) under limited nitrogen nutrition. However, leaf senescence was similar in both lines. To test whether SAG12 is involved in N remobilization from organs other than the leaves, we tested whether root N could be used in N mobilization to the seeds. Root architecture, N uptake capacity and 15N partitioning were compared in the wild type and sag12 under either high nitrogen (HN) or low nitrogen (LN) conditions. No differences in root architecture or root N uptake capacity were observed between the lines under HN or LN. However, under LN conditions, there was an accumulation of 15N in the sag12 roots compared to the wild type with lower allocation of 15N to the seeds. This was accompanied by an increase in root N protein contents and a significant decrease in root cysteine protease activity. SAG12 is expressed in the root stele of the plants at the reproductive stage, particularly under conditions of LN nutrition. Taken together, these results suggest a new role for SAG12. This cysteine protease plays a crucial role in root N remobilization that ensures seed filling and sustains yields when nitrogen availability is low

Revisiting the Complementarity between Education and Training: The Role of Personality, Working Tasks and Firm Effects

This paper addresses the question to which extent the complementarity between education and training can be attributed to differences in observable characteristics, i.e. to individual, job and firm specific characteristics. The novelty of this paper is to analyze previously unconsidered characteristics, in particular, personality traits and tasks performed at work which are taken into account in addition to the standard individual specific determinants. Results show that tasks performed at work are strong predictors of training participation while personality traits are not. Once working tasks and other job related characteristics are controlled for, the skill gap in training participation drops considerably for off-the-job training and vanishes for on-the-job training

Genomic Characterization of the Taylorella Genus

The Taylorella genus comprises two species: Taylorella equigenitalis, which causes contagious equine metritis, and Taylorella asinigenitalis, a closely-related species mainly found in donkeys. We herein report on the first genome sequence of T. asinigenitalis, analyzing and comparing it with the recently-sequenced T. equigenitalis genome. The T. asinigenitalis genome contains a single circular chromosome of 1,638,559 bp with a 38.3% GC content and 1,534 coding sequences (CDS). While 212 CDSs were T. asinigenitalis-specific, 1,322 had orthologs in T. equigenitalis. Two hundred and thirty-four T. equigenitalis CDSs had no orthologs in T. asinigenitalis. Analysis of the basic nutrition metabolism of both Taylorella species showed that malate, glutamate and alpha-ketoglutarate may be their main carbon and energy sources. For both species, we identified four different secretion systems and several proteins potentially involved in binding and colonization of host cells, suggesting a strong potential for interaction with their host. T. equigenitalis seems better-equipped than T. asinigenitalis in terms of virulence since we identified numerous proteins potentially involved in pathogenicity, including hemagluttinin-related proteins, a type IV secretion system, TonB-dependent lactoferrin and transferrin receptors, and YadA and Hep_Hag domains containing proteins. This is the first molecular characterization of Taylorella genus members, and the first molecular identification of factors potentially involved in T. asinigenitalis and T. equigenitalis pathogenicity and host colonization. This study facilitates a genetic understanding of growth phenotypes, animal host preference and pathogenic capacity, paving the way for future functional investigations into this largely unknown genus

Pavlova Veron

Pavlova Butcher emend. Véron Fig. 13 Included species Pavlova gyrans Butcher 1952: pl. II, figs 35–38. Chrysocapsa granifera Mack 1954: fig. 1. – Chrysocapsella granifera (Mack) Bourrelly 1957. – Pavlova granifera (Mack) Green 1973. Pavlova pinguis Green 1967: fig. 1. Emended description Motile, free-swimming, highly metabolic cells with two unequal flagella and a short haptonema. Longer anterior flagellum with fine non-tubular hairs and tiny knob-scales (i.e., ʻdense bodiesʼ), which may or may not be present on the cell body. A pit or canal penetrating the cell near the long anterior flagellum. Chloroplast with a central, large and campylotropous pyrenoid bulging posteriorly and a conspicuous E located on the inner side near the flagellar bases. Non-motile cells in unstratified mucilage with incomplete appendages. Key to the genera The hierarchisation of cytomorphological criteria to provide a simple key to the identification of taxa is not always easy. In his proposal based on characters of the motile cells, Green (1980) used the morphology of the flagella and haptonema as the first criterion, followed by the characters of the stigma, knob-scales, metabolism and the general shape of the cells. It appears today that the combined characters of the pyrenoid, the stigma and the thylakoids are sufficient to discriminate between the four genera (Fig. 14).Published as part of Véron, Benoît, Rougier, Etienne, Taylor, Anthony & Goux, Didier, 2023, New species of Pavlovophyceae (Haptophyta) and revision of the genera Exanthemachrysis, Rebecca and Pavlova, pp. 21-47 in European Journal of Taxonomy 861 on page 40, DOI: 10.5852/ejt.2023.861.2063, http://zenodo.org/record/771025

New species of Pavlovophyceae (Haptophyta) and revision of the genera Exanthemachrysis, Rebecca and Pavlova

International audienceThe justification of the 4 genera that currently compose the class Pavlovophyceae is based on a low number of species and a relative paucity of available, traceable and referenced cultures. Previous integrative phylogeny work revealed strains that can refine and strengthen our knowledge of the genera in the class. The application of multiple light and electron microscopy techniques allowed us to prioritize the cytomorphological characters (pyrenoid, thylakoid, stigma, knob-scales, life stage / life cycle) used for the taxonomy of these algae and to describe two new species: Exanthemachrysis fresneliae Véron sp. nov. and Rebecca billardiae Véron sp. nov. Consequently, revisions of the two genera Exanthemachrysis Lepailleur emend. Véron and Rebecca Green emend. Véron were made. In addition, the genus Pavlova Butcher emend Véron is revised in the light of these characters. Particular emphasis is placed on the life stages and habitat of the species

Rebecca Veron

Rebecca Green emend. Véron Figs 7–9 Included species Rebecca salina (Carter) Green 2000. – Nephrochloris salina Carter 1937: pl. 2, figs 10–22. – Pavlova mesolychnon van der Veer 1969: figs 1–21. – Pavlova salina (Carter) Green 1976: pls. 1–2. Rebecca helicata (van der Veer) Green 2000. – Pavlova helicata van der Veer 1972: figs 1–8. Rebecca billardiae sp. nov. Emended description Cells solitary, free-swimming, sometimes immobile, elongated and slightly compressed or angular to almost cubic, with two unequal flagella and short haptonema. Longer anterior flagellum with fine nontubular hairs, posterior flagellum vestigial. A pit or canal penetrating the cell near the long anterior flagellum. Clavate or mono-constricted scales on the cell body and rows of di- or trimeric scales on the anterior flagellum. Pale yellow-green to golden-brown bilobed single chloroplast with parallel and helicoidal thylakoid arrangement, stigma and pyrenoid absent.Published as part of Véron, Benoît, Rougier, Etienne, Taylor, Anthony & Goux, Didier, 2023, New species of Pavlovophyceae (Haptophyta) and revision of the genera Exanthemachrysis, Rebecca and Pavlova, pp. 21-47 in European Journal of Taxonomy 861 on page 35, DOI: 10.5852/ejt.2023.861.2063, http://zenodo.org/record/771025

Design of Non-Haemolytic Nanoemulsions for Intravenous Administration of Hydrophobic APIs

Among advanced formulation strategies, nanoemulsions are considered useful drug-delivery systems allowing to improve the solubility and the bioavailability of lipophilic drugs. To select safe excipients for nanoemulsion formulation and to discard any haemolytic potential, an in vitro miniaturized test was performed on human whole blood. From haemolysis results obtained on eighteen of the most commonly used excipients, a medium chain triglyceride, a surfactant, and a solubilizer were selected for formulation assays. Based on a design of experiments and a ternary diagram, the feasibility of nanoemulsions was determined. The composition was defined to produce monodisperse nanodroplets with a diameter of either 50 or 120 nm, and their physicochemical properties were optimized to be suitable for intravenous administration. These nanoemulsions, stable over 21 days in storage conditions, were shown to be able to encapsulate with high encapsulation efficiency and high drug loading, up to 16% (w/w), two water practically insoluble drug models: ibuprofen and fenofibrate. Both drugs may be released according to a modulable profile in sink conditions. Such nanoemulsions appear as a very promising and attractive strategy for the efficient early preclinical development of hydrophobic drugs

Optimising extraction of extracellular polymeric substances (EPS) from benthic diatoms: comparison of the efficiency of six EPS extraction methods

International audienc

Pavlova Veron

Genus Pavlova Butcher emend. Véron Figs 10–13 The unidentified strains of Pavlova (AC248 and AC250) were chosen for study because none had ever been examined within the sub-clade 3.2 (Bendif et al. 2011); both strains were found to have the same cytomorphological characteristics as the genus Pavlova. Description of strains AC248 and AC250 Non-motile cells are occasionally present in cultures, clustered to a few in a loose mucilage (Fig. 11A) and showing a reduced flagellar appendage. Motile cells are slightly ovoid (5.9 µm ± 0.5 × 5.2 µm ± 0.4, n = 49), free swimming and highly metabolic (Fig. 10). Emergence of the appendages is from a narrow, shallow sub-apical pit (Fig. 12A). Except at its base (Fig. 12E), the AF (9.5 µm ± 3.8, n = 12) is coated with several layers of regularly spaced (Fig. 12D) flat and ovoid KS (≈ 47 × 34 nm, n = 4) with a slight median constriction and with fine non-tubular hairs (Fig. 12C). The smooth and short PF (1.9 µm ± 0.5, n = 6) is tapered distally (Fig. 12B). The bipartite H (1.1 µm ± 0.2, n = 7) consists of a proximal part of constant diameter and a distal part of equal length and smaller diameter. The single cup-shaped parietal C (Fig. 11B) contains bundles of thylakoids grouped in stacks three to five (Fig. 11C). One end of the C, near the pit and F bases, contains a conspicuous orange E (Fig. 10A–B) consisting of a cluster of osmiophilic globules located along its inner surface (Fig. 11B, D). In the centre of the C, opposite the F base, is a PY forming an ovoid bulge at the cell surface (Figs 10C, 11B, 12A). In transverse section, this protruding PY has the unusual aspect of a thick, wide utricle (Fig. 13A–B, D) curving in on itself (Fig. 13B–C) and entirely surrounded by the C-membrane bordered by the periplastic ER. Details of the pyrenoid of Pavlova spp. This particular form of PY, present in strains AC248, AC250 and also AC33 (Fig. 13D), had previously been observed in various species of Pavlova (i.e., P. pinguis, P. gyrans and P. granifera) but had not been retained as a marker of the genus. It turns out that with all strains of Pavlova for which we now have sections, this PY is a very distinctive feature of the genus. Indeed, at the time of the revision of the species P. pinguis, Green (1980) observed this pyrenoid very clearly in posterior position which he described as “large and conspicuous, frequently being pushed into a bulge at the posterior end of the cell.”. He also noted that this PY is “...frequently penetrated by a tubular invagination containing cytoplasmic material...”. In fact, his illustrations (see his figs 8, 44, 45) clearly show the curved shape of this PY in P. pinguis, as does fig. 7F of Bendif et al. (2011). In their revision of P. gyrans, Green & Manton (1970) noted the central position of the PY within the C as well as its prominent bulging shape but did not examine thin-sections in TEM allowing them to see its curved shape. In their revision of the genus Pavlova they retained the fact that the C is bilobed with a prominent PY. Bendif et al. (2011) also showed this recurving PY in P. gyrans (see their fig. 6G) but retained only the bulge it forms on the cell. For P. granifera, Green (1973) showed the same shape and organisation of the PY (see his fig. 4) with an extension this time towards the interior of the cell (see his fig. 35), a situation we also observed only in the case of Pavlova AC 250 (Fig. 13C). Green (1973) did not retain the singular shape of this PY but reports in his revision of the P. granifera, that the PY is “discretely bulging towards the interior of the cell” (Green 1980). Bendif et al. (2011) also observe this pyrenoid in P. granifera but with less detail. The singular shape of this PY that we describe as campylotropous is indeed a distinctive feature of the species of the genus Pavlova since in Exanthemachrysis (the other genus of Pavlovophyceae with a bulging pyrenoid) the two species now described do not show such a recurving shape, but a simple sphero-ovoid PY (see for E. gayraliae: Gayral & Fresnel 1979: figs 11–12, 21–22 and Bendif et al. 2011: fig. 4E; for E. fresneliae sp. nov.: Fig. 3). When Butcher (1952) erected the genus Pavlova, he noted the presence of “leucosin bodies” in the posterior part of the cells and his drawings (see Butcher 1952: pl. II, figs 35–37) clearly show what is now known to be this type of PY. He did not retain this character as distinctive of the genus, nor did Green (1967), as cited above, when describing P. pinguis and his subsequent revision of the genus Pavlova. Bendif et al. (2011) introduced a more detailed description of the single C in their revised description by stating that it had a “posterior bulging pyrenoid and conspicuous eyespot on the inner surface near the flagellar pit”. Taxonomic outcome: a revised description of Pavlova The particular and very characteristic shape of the pyrenoid in all species of Pavlova makes it a very distinctive feature that leads us to a revision of the genus description.Published as part of Véron, Benoît, Rougier, Etienne, Taylor, Anthony & Goux, Didier, 2023, New species of Pavlovophyceae (Haptophyta) and revision of the genera Exanthemachrysis, Rebecca and Pavlova, pp. 21-47 in European Journal of Taxonomy 861 on pages 36-40, DOI: 10.5852/ejt.2023.861.2063, http://zenodo.org/record/771025