Search results for "Atom"
showing 10 items of 31559 documents
Biological films adhering to the oral soft tissues: Structure, composition, and potential impact on taste perception
2018
The role of free-flowing saliva in taste perception is increasingly recognized, but saliva is also present in the mouth as films intimately associated to soft or hard tissues. On mucosal surfaces, particularly on the tongue, the structure and composition of such films (including its microbial constitutive part) may play a particular role in the sense of taste due to their proximity with the taste anatomical structures. This review compiles the current knowledge on the structure of biological films adhering to oral mucosae and on their biochemical and microbiological composition, before presenting possible implications for taste perception. PRACTICAL APPLICATIONS: The understanding of the ro…
Records and Distribution Corrections on Palaearctic Tenebrionoidea (Coleoptera)
2020
Records and faunistic information are provided for 96 Palaearctic species of tenebrionoid beetles of the families Aderidae, Anthicidae, Melandryidae, Mordellidae, Mycetophagidae, Oedemeridae, Prostomidae, Pyrochroidae, Tenebrionidae and Tetratomidae. The first records of Agnathus decoratus Germar, 1818, Cynaeus angustus (Le Conte, 1851), Mordella huetheri Ermisch, 1956 and Prostomis mandibularis (Fabricius, 1801) for the whole Baltic region of Europe are presented.
Is maternal thyroid hormone deposition subject to a trade-off between self and egg because of iodine?
2021
ABSTRACT Maternal hormones constitute a key signalling pathway for mothers to shape offspring phenotype and fitness. Thyroid hormones (THs; triiodothyronine, T3; and thyroxine, T4) are metabolic hormones known to play crucial roles in embryonic development and survival in all vertebrates. During early developmental stages, embryos exclusively rely on exposure to maternal THs, and maternal hypothyroidism can cause severe embryonic maldevelopment. The TH molecule includes iodine, an element that cannot be synthesised by the organism. Therefore, TH production may become costly when environmental iodine availability is low. This may yield a trade-off for breeding females between allocating the …
The role of heterochrony in Schizanthus flower evolution- a quantitative analysis
2021
Abstract Changes in the timing of development within a lineage (heterochrony) have an enormous impact on floral diversification. However, comparative quantitative studies in a broad range of ontogenetic stages are still needed to identify the role of different heterochronic processes shaping diversification patterns. In this study, changes in petal development were compared across species in the genus Schizanthus showing floral diversification mediated by pollinators. In this genus, transitions from bee- to hummingbird- and moth- pollination are associated with lower lip diversification. Variation in size and shape of petals was quantified at key ontogenetic stages by using a traditional an…
Medium-size droplets of methyl ricinoleate are reduced by cell-surface activity in the gamma-decalactone production by Yarrowia lipolytica.
2000
International audience; Size of methyl ricinoleate droplets during biotransformation into gamma-decalactone by Yarrowia lipolytica was measured in both homogenized and non-homogenized media. In non-homogenized but shaken medium, droplets had an average volume surface diameter d32 of 2.5 microm whereas it was 0.7 microm in homogenized and shaken medium. But as soon as yeast cells were inoculated, both diameters became similar at about 0.7 microm and did not vary significantly until the end of the culture. The growth of Y. lipolytica in both media was very similar except for the lag phase which was lowered in homogenized medium conditions.
Relation of lenacil metabolism with growth inhibition of acer pseudoplatanus cell suspension
1983
Abstract The action of lenacil, a herbicide which inhibits photosynthesis, was studied on Acer pseudoplatanus cell suspensions. The compound was quickly and thoroughly metabolized by cells into two major chloroform-extractable metabolites, but cell growth was temporarily inhibited while some cells were killed. As cell suspensions were non-photosynthetic, the data suggest that lenacil has site(s) of action other than that of photosynthesis. However, as the effects on photosynthesis occur at much lower concentrations (Hilton et al., Weeds, 12 (1964) 129), the effects on cell growth may be considered as secondary.
Effects of magnesium deprivation on development and biomineralization in the sea urchin Arbacia lixula
2019
Echinoderms have an extensive endoskeleton composed of magnesian calcite and occluded matrix proteins. As biomineralization in sea urchin larvae is sensitive to the Magnesium:Calcium ratio of seawater, we investigated the effects of magnesium deprivation on development and skeletogenesis in the sea urchin Arbacia lixula. We focused on the localization of the skeletogenic cells (primary mesenchyme cells) and the spatial expression of associated genes. Embryos reared in Mg-free seawater exhibited developmental delay from 6-h post-fertilization and at 24 h embryos showed complete lack of biomineral formation. Larvae (48–72 h) exhibited severe skeleton malformations. Fluorescent labelling revea…
Vascular bundle modifications in nodes and internodes of climbing Marantaceae
2020
AbstractNodes are interfaces between stems and leaves. Vascular bundles originate here and elongate into leaves and internodes. In Marantaceae, internodal bundles are highly diverse, including inverted bundles in the climbing genus Haumania. The objective of this paper is to characterize bundle forms, their position across the stem and their connection to leaves and short shoots in Haumania spp. and other unrelated African branch-angle climbers in the family (Hypselodelphys, Trachyphrynium). We question whether bundle inversion is a genus-specific trait in Haumania or related to the climbing growth form. Vascular bundles in internodes are scattered across the stem diameter in a characterist…
A harvestman with elaborate palpal pliers, Thunbergia gretae n. gen. n. sp. from China (Opiliones: Sclerosomatidae: Gagrellinae)
2020
Abstract Based on the unusual characteristics of the male pedipalp and male genital morphology, a new genus and new species of Gagrellinae harvestmen, Thunbergia gretae n. gen. n. sp. (male and female) from Shaanxi Province, China, is proposed. The tibia and tarsus of the pedipalp form elaborate palpal claws, resembling gaspipe pliers, probably used to grasp the legs or the pedipalps of the female during courtship. There is no comparable modification of the pedipalp in the female. The penis lacks wing or sac-like (saccate) elements normally present in Gagrellinae, and the penis base is markedly inflated to form a bulb-like structure harbouring the penis muscle. Two or three opisthosomal ter…
<p><strong>In BOLD we trust? A commentary on the reliability of specimen identification for DNA barcoding: a case study on burrower bugs …
2016
An assessment was performed regarding the accuracy of various types of data deposited in the Barcode of Life Data system (BOLD) related to the true bug family Cydnidae (Hemiptera: Heteroptera). Taxonomic nomenclature and classification, identification reliability, and the correctness of the data provided in the "Taxon description" were analyzed and commented on with respect to both available versions of the BOLD system, i.e. version 3 and beta version 4. Numerous mistakes in taxonomy, the relevance of the taxa names, and species misidentifications in BOLD version 3 were found and, more importantly, similar errors were detected in BOLD version 4 as well. We suggest that if the BOLD system is…