New Record of Dendronephthya sp. (Family: Nephtheidae) from Mediterranean Israel: Evidence for Tropicalization?

Bio-invasions have the potential to provoke cascade effects that can disrupt natural ecosystems and cause ecological regime shifts. The Mediterranean Sea is particularly prone to bio-invasions as the changing water conditions, evoked by climate change, are creating advantageous conditions for Lessepsian migrants from the Red Sea. Recently, in May 2023, a new alien species was documented in the Mediterranean Sea-a soft coral of the genus Dendronephthya. This discovery was made by divers conducting 'Long-Term Ecological Research' surveys, along the coast of Israel, at a depth of 42 m. Genetic and morphological testing suggest that the species identity may be Dendronepthya hemprichi, an Indo-Pacific coral, common in the Red Sea. According to life history traits of this species, such as accelerated attachment to available surfaces and fast growth, we expect it to rapidly expand its distribution and abundance across the Mediterranean Sea.

Molecular and skeletal fingerprints of scleractinian coral biomineralization: From the sea surface to mesophotic depths.

Reef-building corals, the major producers of biogenic calcium carbonate, form skeletons in a plethora of morphological forms. Here we studied skeletal modifications of Stylophora pistillata (clade 4) colonies that adapt to increasing depths with decreasing ambient light. The coral show characteristic transitions from spherical morphologies (shallow depths, 5 m deep) to flat and branching geometries (mesophotic depths, 60 m deep). Such changes are typically ascribed to the algal photosymbiont physiological feedback with the coral that host them. We find specific fine-scale skeletal variability in accretion of structure at shallow- and mesophotic depth morphotypes that suggest underlying genomic regulation of biomineralization pathways of the coral host. To explain this, we conducted comparative morphology-based analyses, including optical and electron microscopy, tomography and X-ray diffraction analysis coupled with a comprehensive transcriptomic analysis of S. pistillata. The samples originated from Gulf of Eilat in the Red Sea collected along a depth gradient from shallow to mesophotic depths (5 to 60 m). Additional samples were experimentally transplanted from 5 m to 60 m and from 60 m to 5 m. Interestingly, both morphologically and functionally, transplanted corals partly adapt by exhibiting typical depth-specific properties. In mesophotic depths, we find that the organic matrix fraction is enriched in the coralla, well matching the overrepresentation of transcripts encoding biomineralization "tool-kit" structural extracellularproteins that was observed. These results provide insights into the molecular mechanisms of calcification and skeletal adaptation that repeatedly allowed this coral group to adapt to a range of environments presumably with a rich geological past. STATEMENT OF SIGNIFICANCE: Understanding the reef coral physiological plasticity under a rapidly changing climate is of crucial importance for the protection of coral reef ecosystems. Most of the reef corals operate near their upper limit of heat tolerance. A possible rescue for some coral species is migration to deeper, cooler mesophotic depths. However, gradually changing environmental parameters (especially light) along the depth gradient pose new adaptative stress on corals with largely unknown influences on the various biological molecular pathways. This work provides a first comprehensive analysis of changes in gene expression, including biomineralization "tool kit" genes, and reports the fine-scale microstructural and crystallographic skeletal details in S. pistillata collected in the Red Sea along a depth gradient spannign 5 to 60 m.

Optimization of skeletal protein preparation for LC-MS/MS sequencing yields additional coral skeletal proteins in Stylophora pistillata.

Stony corals generate their calcium carbonate exoskeleton in a highly controlled biomineralization process mediated by a variety of macromolecules including proteins. Fully identifying and classifying these proteins is crucial to understanding their role in exoskeleton formation, yet no optimal method to purify and characterize the full suite of extracted coral skeletal proteins has been established and hence their complete composition remains obscure. Here, we tested four skeletal protein purification protocols using acetone precipitation and ultrafiltration dialysis filters to present a comprehensive scleractinian coral skeletal proteome. We identified a total of 60 proteins in the coral skeleton, 44 of which were not present in previously published stony coral skeletal proteomes. Extracted protein purification protocols carried out in this study revealed that no one method captures all proteins and each protocol revealed a unique set of method-exclusive proteins. To better understand the general mechanism of skeletal protein transportation, we further examined the proteins' gene ontology, transmembrane domains, and signal peptides. We found that transmembrane domain proteins and signal peptide secretion pathways, by themselves, could not explain the transportation of proteins to the skeleton. We therefore propose that some proteins are transported to the skeleton via non-traditional secretion pathways.

A contemporary atlas of the mouse diaphragm: myogenicity, vascularity, and the Pax3 connection.

The thoracic diaphragm is a unique skeletal muscle composed of costal, crural, and central tendon domains. Although commonly described in medical textbooks, newer insights into the diaphragm cell composition are scarce. Here, using reporter mice, combined with gene expression analyses of whole tissues and primary cultures, we compared the diaphragm domains and their myogenic progenitors (i.e., Pax3/7 satellite cells). The outcomes of these analyses underscore the similarities between the myogenic aspects of the costal and crural domains. Expression levels of all myogenic genes examined (except Pax3) were strongly affected in mdx (dystrophin-null) mice and accompanied by an increase in fibrosis- and adiposity-related gene expression. Cell culture studies further indicated the presence of a non-myogenic Pax3-expressing population, potentially related to vascular mural cells. We additionally investigated the diaphragm vasculature. XLacZ4 and Sca1-GFP transgenes allowed a fine definition of the arterial and microvasculature network based on reporter expression in mural cells and capillary endothelium, respectively. We also provide insights into the organization of the diaphragm venous system, especially apparent in the central tendon and exhibiting arcades lined with fat-containing cells. The novel information in this "contemporary atlas" can be further explored in the context of diaphragm pathology and genetic disorders.

Regulatory regions in the promoter and first intron of Sparus aurata growth hormone gene: Repression of gene activity by a polymorphic minisatellite.

Transcriptional activity of the gilthead sea bream (Sparus aurata) growth hormone (saGH) gene promoter has been investigated using transient transfection assays in GH3 cells. Analysis of two fragments (1.7 kb and a 5'-deleted 0.9 kb) of saGH gene promoter directed luciferase reporter gene activity, indicating transcriptional activity of both fragments in vitro. The shorter fragment, containing five potential binding sites for the pituitary-specific transcription factor GHF-1/Pit-1, two cAMP-response elements and two glucocorticoid-response elements conferred higher reporter gene activity than the longer fragment. This result suggests presence of an inhibitory region upstream of the saGH promoter. Transient transfection assays were also used to investigate the effect of the polymorphic minisatellite saGHFIM found in the first intron of saGH gene on gene expression in four cell lines: fish pituitary (RTP-2) and non-pituitary (RTH-149) and mammalian pituitary (GH3) and non-pituitary (HEK293T). Luciferase activity was repressed by saGHFIM containing a high number of tandem repeats compared to a Control construct and to a construct with a smaller number of tandem repeats. Moreover, this repression was dependent on the orientation of the repeats relative to the viral promoter. These in vitro results imply that long GH introns might influence GH gene expression in vivo.