Mapping the molecular and structural specialization of the skin basement membrane for inter-tissue interactions

Inter-tissue interaction is fundamental to multicellularity. Although the basement membrane (BM) is located at tissue interfaces, its mode of action in inter-tissue interactions remains poorly understood, mainly because the molecular and structural details of the BM at distinct inter-tissue interfaces remain unclear. By combining quantitative transcriptomics and immunohistochemistry, we systematically identify the cellular origin, molecular identity and tissue distribution of extracellular matrix molecules in mouse hair follicles, and reveal that BM composition and architecture are exquisitely specialized for distinct inter-tissue interactions, including epithelial–fibroblast, epithelial–muscle and epithelial–nerve interactions. The epithelial–fibroblast interface, namely, hair germ–dermal papilla interface, makes asymmetrically organized side-specific heterogeneity in the BM, defined by the newly characterized interface, hook and mesh BMs. One component of these BMs, laminin α5, is required for hair cycle regulation and hair germ–dermal papilla anchoring. Our study highlights the significance of BM heterogeneity in distinct inter-tissue interactions.

Determinants of content marketing effectiveness: Conceptual framework and empirical findings from a managerial perspective

Content marketing has gained momentum around the world and is steadily gaining importance in the marketing mix of organizations. Nevertheless, it has received comparatively little attention from the scientific community. In particular, there is very little knowledge about the effectiveness, optimal design and implementation of content marketing. In this study, the authors conceptualize content marketing as a set of activities that are embedded in and contingent on the specific organizational context. Based on this framework, the authors empirically investigate the context features determining content marketing effectiveness from a managerial perspective, using primary data collected from senior marketers in 263 organizations from various sectors and across different size categories, conducting multiple regression analysis. The empirical results indicate that clarity and commitment regarding content marketing strategy and a content production in line with the organization’s target groups’ content needs as well as normative journalistic quality criteria are context factors associated with higher content marketing effectiveness. The outcomes also reveal that regularly measuring content marketing performance and using the data obtained as guidance for improving content offerings positively influence content marketing effectiveness, as do structural specialization and specialization-enabling processes and systems. The insights provided in this study could offer important theoretical contributions for research on content marketing and its effectiveness and may help practitioners to optimize the design and implementation of content marketing initiatives.

Aerial and aquatic respiration in littoral Oniscidea (Isopoda) from Southern California, USA

The large radiation of terrestrial isopods (suborder Oniscidea) includes several families that are represented primarily in marine-littoral or riparian habitats. Among these are members of Ligiidae and Tylidae as well as several basal families within the section Crinocheta. Structural and physiological evidence supports a marine-littoral ancestry of the Oniscidea. We examined aerial and aquatic respiration (measured as VCO2) in six species of marine-littoral Oniscidea representing five families, as well as one riparian and one endogean species. Complimentary data were collected for immersion tolerance and whole-animal permeability in air, and structural specialization of the respiratory pleopods was examined using SEM. Ligia occidentalis Dana, 1853 (marine, littoral) and Ligidium lapetum Mulaik & Mulaik, 1942 (riparian) showed similar VCO2 in air and water. VCO2 in air for the other species was significantly higher than in water. Compared across species, aerial VCO2 scaled with mass in accordance with Kleiber’s law (β = 0.774) while aquatic VCO2 increased in approximate proportion to mass (β = 0.957). At least some specimens of the six marine-littoral species survived over 24 h immersion. Ligidium lapetum and the endogean trichoniscid Brackenridgia heroldi (Arcangeli, 1932) also tolerated prolonged immersion in freshwater but did not survive beyond 5–6 h, probably due to limited capacity for hyper-regulation. The upper shore sand-burrowers, Tylos punctatus Holmes & Gay, 1909 and Alloniscus perconvexus Dana, 1856 had the lowest permeability among the study species and are the only representatives with elaborated pleopodal respiratory fields (Alloniscus) and lungs (Tylos). The ventral lung spiracles of T. punctatus are surrounded by an extensive cuticle meshwork and we propose that this functions as a plastron field to enhance aquatic gas exchange. Collectively, the results show that littoral species tolerate significant periods of immersion, allowing them to withstand habitat inundation during spring high tides, storm swells and, in riparian species, rainstorms and snowmelt.

Mapping the molecular and structural specialization of the skin basement membrane for inter-tissue interactions

Inter-tissue interaction is fundamental to multicellularity. Although the basement membrane (BM) is located at tissue interfaces, its mode of action in inter-tissue interactions remains poorly understood, mainly because the molecular and structural details of the BM at distinct inter-tissue interfaces remain unclear. By combining quantitative transcriptomics and immunohistochemistry, we systematically identify the cellular origin, molecular identity and tissue distribution of extracellular matrix molecules in mouse hair follicles, and reveal that BM composition and architecture are exquisitely specialized for distinct inter-tissue interactions, including epidermal–fibroblast, epidermal–muscle and epidermal–nerve interactions. The epidermal–fibroblast interface, namely, hair germ–dermal papilla interface, makes asymmetrically organized side-specific heterogeneity in BM, defined by the newly characterized interface, hook and mesh BMs. One component of these BMs, laminin α5, is required for the topological and functional integrity of hair germ–dermal papilla interactions. Our study highlights the significance of BM heterogeneity in distinct inter-tissue interactions.

The zooarchaeology of complexity and specialization during the Upper Palaeolithic in Western Europe

Over the last twenty years attempts have been made to determine the nature of Upper Palaeolithic hunting specialization. This chapter traces assemblage structural ‘specialization’, where faunal assemblages are dominated by a single species, vs ‘diversity’, in which all recorded species are well represented, between 45,000 and 10,000 bp (Châtelperronian to Azilian), and demonstrates regularity in the archaeozoological record. It moves away from the assumption that assemblages with at least 90% of bones attributable to a single species result from specialized hunting strategies, and seeks explanations for patterns of diversification. The study also deals with the Late Glacial Maximum with its narrowing resource base and the Magdalenian of southwest France, when specialized reindeer hunting is traditionally considered of paramount importance. The chapter uses measures of diversity and evenness to quantify variation observed through time, highlighting a peak in single-species exploitation during the Middle Upper Palaeolithic. Finally, interpretations are offered for future consideration.

The CNS connectome of a tadpole larva of Ciona intestinalis (L.) highlights sidedness in the brain of a chordate sibling

Left-right asymmetries in brains are usually minor or cryptic. We report brain asymmetries in the tiny, dorsal tubular nervous system of the ascidian tadpole larva, Ciona intestinalis. Chordate in body plan and development, the larva provides an outstanding example of brain asymmetry. Although early neural development is well studied, detailed cellular organization of the swimming larva’s CNS remains unreported. Using serial-section EM we document the synaptic connectome of the larva’s 177 CNS neurons. These formed 6618 synapses including 1772 neuromuscular junctions, augmented by 1206 gap junctions. Neurons are unipolar with at most a single dendrite, and few synapses. Some synapses are unpolarised, others form reciprocal or serial motifs; 922 were polyadic. Axo-axonal synapses predominate. Most neurons have ciliary organelles, and many features lack structural specialization. Despite equal cell numbers on both sides, neuron identities and pathways differ left/right. Brain vesicle asymmetries include a right ocellus and left coronet cells.

Pollination ecology and circadian patterns of inflorescence opening of the Madagascan climber Dalechampia aff. bernieri (Euphorbiaceae)

Floral morphology often directly influences interactions with pollinators, but less is known about the role of extrafloral structures. We studied the relationship between bract motility, floral structural specialization and pollination in Dalechampia aff. bernieri, an endemic Madagascan species with floral structures indicating specialized buzz-pollination. We measured circadian bract angles in 47 inflorescences from 11 plants of D. aff. bernieri; in addition, we recorded any flower-visiting insects observed. The inflorescences had motile bracts with mean angles varying from ~50° at 00h00 to ~90° at 10h45. They were visited by buzz-pollinating Nomia viridilimbata bees (Halictidae), but also by non-buzz-pollinating Liotrigona bees (Apidae). The temporal pattern of bract motility observed in D. aff. bernieri may represent an extra-floral specialization to reduce visitation by non-pollinating visitors while maximizing visitation by diurnal buzz-pollinating bees.