Opercular Bones Research Articles

Threatened fishes of the world: Schizothorax (Racoma) biddulphi (Günther, 1876) (Cyprinidae)

In order to study the individual biology of endemic fish in China, lay a foundation for the conservation of its germplasm resources, and consolidate the basic biological data of endemic fish in the world. According to the ethical code and fishing permit, 21 samples of Schizothorax (Racoma) biddulphi (Günther, 1876) were collected from the Muzati River in Tarim River system from 2021 to 2022, and their morphological characteristics, age identification and anatomical observation were analyzed by classical biological methods. S. biddulphi has a long body, a conical head, a pointed snout and a lower mouth. Requires 2 pairs. The scales are small and neatly arranged; Bare or scaly chest; The lateral line scale is slightly larger. The lateral line is complete. The correlation equation between body length and body weight is: W = 4.148 × 10-5L2.791. There were 5 kinds of age identification materials: 15+ for lapillus and asteriscus, 14+ for vertebra, 11+ for opercular bone, and 9+ for anal scale. The peritoneal wall of S. biddulphi is black; The tooth type is 2·3·5-5·3·2; The gill harrow was 11~13 for laymen and 15~18 for experts. Diphysocyte; Gallbladder oval; The number of vertebrae is 4+42-43+1, and the number of ribs is 23 or 24. S. biddulphi is a special species in the Tarim River system, and its evolutionary adaptation is closely related to the uplift of the Qinghai-Tibet Plateau.

In vivo imaging of bone collagen dynamics in zebrafish

Type I collagen plays a pivotal role in shaping bone morphology and determining its physical properties by serving as a template for ossification. Nevertheless, the mechanisms underlying bone collagen formation, particularly the principles governing its orientation, remain unknown owing to the lack of a method that enables continuous in vivo observations. To address this challenge, we constructed a method to visualize bone collagen by tagging with green fluorescent protein (GFP) in zebrafish and observed the interactions between osteoblasts and collagen fibers during bone formation in vivo. When collagen type I alpha 2 chain (Col1a2)-GFP was expressed under the control of the osteoblast-specific promoters osx or osc in zebrafish, bone collagen was observed clearly enough to identify its localization, whereas collagen from other organs was not. Therefore, we determined that this method was of sufficient quality for the detailed in vivo observation of bone collagen. Next, bone collagen in the scales, fin rays, and opercular bones of zebrafish was observed in detail, when bone formation is more active. High-magnification imaging showed that Col1a2-GFP can visualize collagen sufficiently to analyze the collagen fiber orientation and microstructure of bones.Furthermore, by simultaneously observation of bone collagen and osteoblasts, we successfully observed dynamic changes in the morphology and position of osteoblasts from the early stages of bone formation. It was also found that the localization pattern and orientation of bone collagen significantly differed depending on the choice of the expression promoter. Both promoters (osx and osc) used in this study are osteoblast-specific, but their Col1a2-GFP localizing regions within the bone were exclusive, with osx region localizing mainly to the outer edge of the bone and osc region localizing to the central area of the bone. This suggests the existence of distinct osteoblast subpopulations with different gene expression profiles, each of which may play a unique role in osteogenesis.These findings would contribute to a better understanding of the mechanisms governing bone collagen formation by osteoblasts.

Length-Weight-Age Relationship of Schizothorax eurystomus Kessler, 1872 and Comparison to Other Snow Trout Species in Central Asia

This study presents a comprehensive analysis of the length-weight relationship, condition factors, and age of Schizothorax eurystomus in the Shakhimardan River basin in Central Asia, along with a comparative perspective to other Schizothorax species in the region. The study found that S. eurystomus exhibits positive allometric growth, which is consistent with similar patterns observed in this species from the Syr Darya River basin. The two analyzed condition factors showed mean values within the normal range, indicating good feeding and environmental conditions. However, significant disparities between minimum and maximum values of these factors indicated varied growth conditions which may be influenced by anthropogenic factors. Age estimation using opercular bones showed variations in the total length among fish of the same age, and a clear age distribution pattern across different sites. Younger fish predominantly inhabited the shallower, warmer, and lower sections of the river, which is impacted by agricultural water diversion, while older specimens were found in areas with higher discharge and deeper pools. Overall, this research provides valuable insights into the life history traits of S. eurystomus, underlining the need for sustainable fishery management and conservation strategies in the Shakhimardan River basin. The findings also emphasize the importance of considering habitat quality and anthropogenic pressures regarding understanding both fish population dynamics and growth patterns.

Skeletal deformities in gilthead seabream (Sparus aurata): exploring the association between mechanical loading and opercular deformation

Fish aquaculture is frequently confronted with skeletal abnormalities. In gilthead seabream (Sparus aurata (Linnaeus, 1758)), opercular deformities are one of the most common types of deformities. Many studies point at potential causal factors, mainly genetic or nutritional. However, no clear consensus has surfaced yet, and other factors known to affect bone formation remain unexplored, including mechanical stressors by external forces or muscle contraction. In this study, we investigated whether an altered mechanical use of the gill cover could be associated with opercular deformities, by inducing a change in the respiratory rate and thus gill ventilation. Juvenile seabreams were reared under 80, 100 or 200% dissolved oxygen (DO) to trigger altered respiration behaviour, and the effect on body and opercular shape was analysed. The main hypothesis was that hypoxic conditions would increase opercular ventilation, which would result in a higher prevalence of opercular deformities. The results show that the hypoxic condition (80% DO) did not trigger a significantly higher prevalence of opercular deformations, though the opposite is true for the hyperoxic condition (200% DO). No effect of oxygen treatment was observed on overall body shape, though deformed opercles showed a pronounced, but non-significant difference in shape across treatments. Morphometric results and µCT scans reveal that deformations mainly occur in the dorsocaudal region of the opercular bone. Although no causal link could be demonstrated, we discuss how these results can indirectly suggest that an altered mechanical loading on the operculum could explain its deformation.

Age and growth assessment of the near-threatened fish Rita rita (Siluriformes: Bagridae) in the Ganges basin

Introduction: Rita rita is a freshwater catfish under threat of extinction, mainly from loss of breeding and nursing grounds. A reliable method for age and growth estimation is needed by fishery managers. Objective: To identify the best body structure for age and growth estimation. Methods: We assessed estimates precision based on Average Percent Error (APE), Coefficient Variation (CV), and Percent Agreement (PA) between readers separately analyzed each calcified structure. We used 390 fish samples from three rivers, Ganga, Yamuna and Ramganga, from September 2018 to August 2019. Results: The three indicators favored the use of vertebrae for age estimation; the growth band seems to be annual and formed from May to September. The growth equations were Lt = 90.19(1-e-0.145(t+0.51)) for Ganga; Lt = 91.19 (1-e-0.14(t+0.59)) for Yamuna and Lt = 89.63 (1-e-0.15(t+0.68)) for Ramganga. Conclusion: This species reaches moderate growth in these rivers, where vertebrae are the recommended age estimation structure, followed, in case of need, by sectioned otoliths, whole otoliths and opercular bones. Pectoral spines should be avoided, especially in older fish.

Effects of pristine or contaminated polyethylene microplastics on zebrafish development

The presence of microplastics in the aquatic ecosystem represents a major issue for the environment and human health. The capacity of organic pollutants to adsorb onto microplastic particles raises additional concerns, as it creates a new route for toxic compounds to enter the food web. Current knowledge on the impact of pristine and/or contaminated microplastics on aquatic organisms remains insufficient, and we provide here new insights by evaluating their biological effects in zebrafish (Danio rerio). Zebrafish larvae were raised in ZEB316 stand-alone housing systems and chronically exposed throughout their development to polyethylene particles of 20–27 μm, pristine (MP) or spiked with benzo[α]pyrene (MP-BaP), supplemented at 1% w/w in the fish diet. While they had no effect at 30 days post-fertilization (dpf), MP and MP-BaP affected growth parameters at 90 and 360 dpf. Relative fecundity, egg morphology, and yolk area were also impaired in zebrafish fed MP-BaP. Zebrafish exposed to experimental diets exhibited an increased incidence of skeletal deformities at 30 dpf as well as an impaired development of caudal fin/scales, and a decreased bone quality at 90 dpf. An intergenerational bone formation impairment was also observed in the offspring of parents exposed to MP or MP-BaP through a reduction of the opercular bone in 6 dpf larvae. Beside a clear effect on bone development, histological analysis of the gut revealed a reduced number of goblet cells in zebrafish fed MP-BaP diet, a sign of intestinal inflammation. Finally, exposure of larvae to MP-BaP up-regulated the expression of genes associated with the BaP response pathway, while negatively impacting the expression of genes involved in oxidative stress. Altogether, these data suggest that long-term exposure to pristine/contaminated microplastics not only jeopardizes fish growth, reproduction performance, and skeletal health, but also causes intergenerational effects.

Zebrafish as a Model to Unveil the Pro-Osteogenic Effects of Boron-Vitamin D3 Synergism.

The micronutrient boron (B) plays a key role during the ossification process as suggested by various in vitro and in vivo studies. To deepen our understanding of the molecular mechanism involved in the osteogenicity of B and its possible interaction with vitamin D3 (VD), wild-type AB zebrafish (Danio rerio) were used for morphometric analysis and transcriptomic analysis in addition to taking advantage of the availability of specific zebrafish osteoblast reporter lines. First, osteoactive concentrations of B, VD, and their combinations were established by morphometric analysis of the opercular bone in alizarin red-stained zebrafish larvae exposed to two selected concentrations of B (10 and 100 ng/ml), one concentration of VD (10 pg/ml), and their respective combinations. Bone formation, as measured by opercular bone growth, was significantly increased in the two combination treatments than VD alone. Subsequently, a transcriptomic approach was adopted to unveil the molecular key regulators involved in the synergy. Clustering of differentially expressed genes revealed enrichment toward bone and skeletal functions in the groups co-treated with B and VD. Downstream analysis confirmed mitogen-activated protein kinase as the most regulated pathway by the synergy groups in addition to transforming growth factor-β signaling, focal adhesion, and calcium signaling. The best-performing synergistic treatment, B at 10 ng/ml and VD at 10 pg/ml, was applied to two zebrafish transgenic lines, Tg(sp7:mCherry) and Tg(bglap:EGFP), at multiple time points to further explore the results of the transcriptomic analysis. The synergistic treatment with B and VD induced enrichment of intermediate (sp7+) osteoblast at 6 and 9 days post fertilization (dpf) and of mature (bglap+) osteoblasts at 15 dpf. The results obtained validate the role of B in VD-dependent control over bone mineralization and can help to widen the spectrum of therapeutic approaches to alleviate pathological conditions caused by VD deficiency by using low concentrations of B as a nutritional additive.

Nusaviichthys nerivelai gen. et sp. nov., an Albian crossognathiform fish from the Tlayúa lagerstätte, Mexico

The fish Nusaviichthys nerivelai gen. et sp. nov. is described here based on well-preserved fossils from the Albian deposits of the Tlayúa quarry, near Tepexi de Rodríguez, Puebla, central Mexico. The occurrence of this new fish from Tlayúa expands the taxonomical and morphological diversity of the crossognathiformes of the Caribbean region of America during the Early Cretaceous. The inclusion of the osteological features of this species into comparative and phylogenetic analyses reveal its belonging to the order Crossognathiformes, suborder Pachyrhizodontoidei, and family Notelopidae; some of the most significant of these features include the presence of a large extrascapula bone; circumorbital bones forming a completely closed ring; medioparietal condition of the skull; posterior infraorbitals hypertrophied, covering the entire cheek, and extended up to the anterior part of the opercular bones; the relative short uroneural 1 anteriorly restricted to the preural 1; and the cycloid scales with a crenulated posterior edge. This new species differs from its relatives in the presence of numerous and small conic teeth in both jaws and vomer; the large triangular gular plate, and the numerous radiating grooves ridges present in the supraorbital, dermosphenotic, skull roof bones, opercular bones, and jaws; and the almost horizontal position of the neural and hemal spines of the last caudal centra. Despite the weak support, the naturalness of this extinct teleost order is recovered in the phylogenetic analysis performed here, which includes this new Mexican fossil fish as well as other crossognathiform genera not included in previous studies.

Comparative studies on age and growth patterns of cultivated and wild Catla catla (Hamilton)

Catla catla (Hamilton) is one of the fastest growing Indian major carps (IMCs) with increasing market demand. Consistent demand and exploitation invites the attention of ichthyologists for its conservation strategies. Age and growth studies play a pivotal role for managing the fishery stocks in different water bodies. Here, we studied the age and growth patterns using opercula of both farm grown as well as the wild grown C. catla adopting standard methodologies. Wild specimens were caught from Harike wetland (Ramsar site) and the cultivated one from a farm at Dhudike in Punjab. High value of correlation coefficient ‘r’ 0.976 (wetland) and 0.983 (farm) reveals the strong relationship in total length and operculum radius of the fish. C. catla achieved average total length from wetland and farm, respectively at 1st (273.44 mm) 2nd (427.44 mm) 3rd (525.49 mm) 4th (624.52 mm) 5th (744.98 mm) 6th (813.62 mm) and 1st (282.1 mm) 2nd (463 mm) 3rd (601.7 mm) year of age of opercular bones study. The growth parameters such as, index of species average size (φh) 135.6 (wetland) and 200.6 (farm), growth constant (Clt) showed two growth phases from both localities i.e. sexual immaturity up to 2 years and sexual maturity afterwards. Whereas, growth characteristic (Cth) has revealed irregular growth pattern at wetland in comparison to growth of fish from farm. The results of this study concluded that the fish experienced more growth from the farm due to better and controlled conditions but, in wetland surrounding conditions were observed to be unfavourable for survival of the fish C. catla.

New insights into benzo[⍺]pyrene osteotoxicity in zebrafish

Persistent and ubiquitous organic pollutants, such as the polycyclic aromatic hydrocarbon benzo[⍺]pyrene (BaP), represent a major threat to aquatic organisms and human health. Beside some well-documented adverse effects on the development and reproduction of aquatic organisms, BaP was recently shown to affect fish bone formation and skeletal development through mechanisms that remain poorly understood. In this work, zebrafish bone-related in vivo assays were used to evaluate the osteotoxic effects of BaP during bone development and regeneration. Acute exposure of zebrafish larvae to BaP from 3 to 6 days post-fertilization (dpf) induced a dose-dependent reduction of the opercular bone size and a depletion of osteocalcin-positive cells, indicating an effect on osteoblast maturation. Chronic exposure of zebrafish larvae to BaP from 3 to 30 dpf affected the development of the axial skeleton and increased the incidence and severity of skeletal deformities. In young adults, BaP affected the mineralization of newly formed fin rays and scales, and impaired fin ray patterning and scale shape, through mechanisms that involve an imbalanced bone remodeling. Gene expression analyses indicated that BaP induced the activation of xenobiotic and metabolic pathways, while negatively impacting extracellular matrix formation and organization. Interestingly, BaP exposure positively regulated inflammation markers in larvae and increased the recruitment of neutrophils. A direct interaction between neutrophils and bone extracellular matrix or bone forming cells was observed in vivo, suggesting a role for neutrophils in the mechanisms underlying BaP osteotoxicity. Our work provides novel data on the cellular and molecular players involved in BaP osteotoxicity and brings new insights into a possible role for neutrophils in inflammatory bone reduction.

Descriptive Study of Some Osteological Parts of Rosy Stone Lapper (Garra rossica) from Mashkid Basin of Iran

Since osteological structures of fishes provide important biological and ecological information, studying these structures is valuable. On the other hand, due to lack of data on the osteology of stone lappers, the present study was conducted to provide detailed descriptive osteology of Garra rossica from Mashkid basin, southeastern Iran, comparing it with those of G. typhlops from the Bagh-e Loveh cave, Iran, G. rossica from Nahang River, Mashkid Basin, and G. persica from Zahak River, Sistan basin. For this purpose, 15 specimens of G. rossica were captured from Ladiz River, Mashkid Basin, using an electrofishing device, and fixed in 10% buffered formalin. Then, the specimens were cleared and stained with alcian blue and alizarin red for osteological investigations. A detailed description of the osteological features of G. rossica was provided. Based on the results, several differences were observed between the four species. G. rossica can be distinguished from G. typhlops, G. persica, and G. rossica based on the shape of suspensorium and opercular series, pharyngobranchial bones, ventral and pectoral girdles, caudal, dorsal, and anal fins skeleton, and shape and number of infraorbital elements.

Comparative analysis of the parasphenoid bone development in Mexican tetra ( Astyanax mexicanus)

Astyanax mexicanus is a teleost fish that belongs to the order Characiform. Ithas two distinct eye morphs as surface-dwelling, pigmented eyed surface fish population, and an eyeless cavefish population. Accumulation of functional mutations in the genes which are important for eye development led to the loss of eyes in cavefish. Some cranial changes have occurred from the direct effect of eye loss in cavefish including size and position of the circumorbital bones, ossified sclera, and the shape of both suborbital 3 and the supraorbital bone. The maxillary teeth, the positions of suborbital 4 to suborbital 6, and the shape of the opercular bone were found to be unaffected by the eye loss. Unlike higher vertebrates, the teleost eyeball does not cover by a bony socket and it has direct communication with the inner neurocranium. However, the influence of eye development on the inner neurocranial bones has gained little attention in research. In A. mexicanus palate bones are mainly made of a series of bones such as parasphenoid bone, basioccipital, vomer, and ethmoid. Among them, parasphenoid bone makes the largest part of the palate. This study was designed to understand the effect of eye loss in cavefish on parasphenoid bone development, shape determination, and bone remodeling activity. A. mexicanus populations; Surface fish and Pachon cavefish at 5dpf, 10 dpf, 20 dpf, 35 dpf, and 60 dpf subjected to alizarin red bone staining. Adult surface fish and two cave populations Pachon and Tinaja cavefish were subjected to micro-CT imaging and morphometric analysis was carried out using those images to compare the parasphenoid bone anatomy amongst these three morphs. TRAP and ALP staining were used to determine the bone remodeling activity in 60 dpf, A. mexicanus populations of surface and Pachon cavefish. A. mexicanus cavefish and surface are similar to each other in bone development, articulation, and ossification with certain exceptions such as late protrusion of lateral wings in cavefish. The straightened parasphenoid bone observed in cavefish and curved parasphenoid bone observed in surface fish beneath the eye orbit. Bone remodeling activity in cavefish was found to be increased compared to the surface fish. Cavefish have a direct or indirect effect on eye loss on the development of bones in the cranial region. Differential bone remodeling activity observed in cave and surface fish may result from the limited resources in the cave environment and as a long-term adaptation into troglomorphic cave environment.

Comparison of Aging Structures and Life History of a Historical Population of Roundtail Chub (Cyprinidae) in the Yampa River, Colorado

The Gila robusta complex includes 3 large cyprinid species native to the Colorado River drainage. All 3 members of this complex, Humpback Chub G. cypha, Bonytail Chub G. elegans, and Roundtail Chub G. robusta, historically occurred in the Yampa River Canyon of Colorado and Utah. Both Humpback Chub and Bonytail Chub are federally listed as endangered, and the Roundtail Chub is now considered either imperiled or vulnerable to extinction by all state management agencies in the Colorado River basin. In late June or early July of 1998, 1999, 2001, and 2002, we collected Roundtail Chub from the Yampa River in Dinosaur National Monument. Our objectives were to determine the efficacy of scales, opercular bones, and otoliths as aging structures, and to describe age, mortality, growth, and tuberculation patterns relative to reproductive stages. We obtained interpretable annuli for 111 fish by using otoliths, 91 fish by using opercles, and 111 fish by using scales. Otolith annuli showed the least measurement error; scale annuli generally agreed with otolith annuli up to approximately 7–8 years, after which scale annuli consistently underestimated otolith annuli. Opercular annuli closely agreed with otolith annuli up to 10–12 years before underestimating otolith annuli. Based on otoliths, the oldest fish was aged at 22 years, with 7 fish exceeding 15 years. Using a linearized catch-curve, Roundtail Chub had an instantaneous mortality rate of –0.158, corresponding to 85% survivorship. Growth in length was initially high and then declined at older ages. Slopes of mass versus length differed between sexes, and females had a slightly greater body mass per unit length than males for lengths above 398 mm TL. Both sexes have similar ages at first reproduction (5–6 years), and both develop tubercles. The greatest tubercle development occurred in males with maturing or running ripe testes, and in females with maturing ovaries.

Craniological Divergence of Two Genetically Closely Related Caucasian Spined Loaches: Cobitis saniae and C. derzhavini (Cobitidae)

The craniological analysis of Cobitis derzhavini from the Mingechaur Reservoir system and C. saniae from the Malyi Kyzylagach Bay drainage and the Alvady River in Azerbaijan did not reveal any fundamental differences in the general morphology of the neurocranium and cranial bones between these species, as well as from the previously studied C. taenia, C. melanoleuca and C. taurica. However, C. derzhavini showed high level of diversity from other Cobitis species in the proportions of some bones, at first, operculum. The results confirm that C. derzhavini is a separate species characterized by a predominance of opercular bone with weakly excised posterior margin, in contrast to opercular bone with deeply excised posterior margin observed in other craniologically studied species of Cobitis and Sabanejewia.

Functional coupling in the evolution of suction feeding and gill ventilation of sculpins (Perciformes: Cottoidei).

Suction feeding and gill ventilation in teleosts are functionally coupled, meaning that there is an overlap in the structures involved with both functions. Functional coupling is one type of morphological integration, a term that broadly refers to any covariation, correlation, or coordination among structures. Suction feeding and gill ventilation exhibit other types of morphological integration, including functional coordination (a tendency of structures to work together to perform a function) and evolutionary integration (a tendency of structures to covary in size or shape across evolutionary history). Functional coupling, functional coordination, and evolutionary integration have each been proposed to limit morphological diversification to some extent. Yet teleosts show extraordinary cranial diversity, suggesting that there are mechanisms within some teleost clades that promote morphological diversification, even within the highly integrated suction feeding and gill ventilatory systems. To investigate this, we quantified evolutionary integration among four mechanical units associated with suction feeding and gill ventilation in a diverse clade of benthic, primarily suction-feeding fishes (Cottoidei; sculpins and relatives). We reconstructed cottoid phylogeny using molecular data from 108 species, and obtained 24 linear measurements of four mechanical units (jaws, hyoid, opercular bones, and branchiostegal rays) from micro-CT reconstructions of 44 cottoids and 1 outgroup taxon. We tested for evolutionary correlation and covariation among the four mechanical units using phylogenetically corrected principal component analysis to reduce the dimensionality of measurements for each unit, followed by correlating phylogenetically independent contrasts and computing phylogenetic generalized least squares models from the first principle component axis of each of the four mechanical units. The jaws, opercular bones, and branchiostegal rays show evolutionary integration, but the hyoid is not positively integrated with these units. To examine these results in an ecomorphological context, we used published ecological data in phylogenetic ANOVA models to demonstrate that the jaw is larger in fishes that eat elusive or grasping prey (e.g., prey that can easily escape or cling to the substrate) and that the hyoid is smaller in intertidal and hypoxia-tolerant sculpins. Within Cottoidei, the relatively independent evolution of the hyoid likely has reduced limitations on morphological evolution within the highly morphologically integrated suction feeding and gill ventilatory systems.

Anti-Osteogenic Activity of Cadmium in Zebrafish

Among the many anthropogenic chemicals that end up in the aquatic ecosystem, heavy metals, in particular cadmium, are hazardous compounds that have been shown to affect developmental, reproductive, hepatic, hematological, and immunological functions in teleost fish. There is also evidence that cadmium disturbs bone formation and skeletal development, but data is scarce. In this work, zebrafish was used to further characterize the anti-osteogenic/osteotoxic effects of cadmium and gain insights into underlying mechanisms. Upon exposure to cadmium, a reduction of the opercular bone growth was observed in 6-days post-fertilization (dpf) larvae and an increase in the incidence of skeletal deformities was evidenced in 20-dpf post-larvae. The extent and stiffness of newly formed bone was also affected in adult zebrafish exposed to cadmium while regenerating their caudal fin. A pathway reporter assay revealed a possible role of the MTF-1 and cAMP/PKA signaling pathways in mechanisms of cadmium osteotoxicity, while the expression of genes involved in osteoblast differentiation and matrix production was strongly reduced in cadmium-exposed post-larvae. This work not only confirmed cadmium anti-osteogenic activity and identified targeted pathways and genes, but it also suggested that cadmium may affect biomechanical properties of bone.

A 3D quantitative method for analyzing bone mineral densities: a case study on skeletal deformities in the gilthead sea bream, Sparus aurata (Linnaeus, 1758)

Skeletal deformities, one of the major threats for aquaculture, have been studied extensively. These include opercular malformations in gilthead sea bream (Sparus aurata), a key fish species for Mediterranean aquaculture. What is causing it and at what morphogenetic level it arises, however, is still unclear. Here we focus on bone formation, at the level of bone mineralization. Several methods have been used to study bone mineralization density (BMD), however, these are frequently limited when targeting a high-resolution, three-dimensional mapping of BMD. We used micro-computed tomography (micro-CT) data to perform such a 3D quantification of BMD levels in gilthead sea bream that showed different levels of opercular bone deformations. This approach has the advantage of not having to rely on calibration phantoms, as long as relative BMD values are needed. The results show an increased BMD in deformed opercles compared to normal ones, especially in a bilaterally-deformed specimen. Furthermore, we show that opercular deformations are not necessarily associated with similar mineralization patterns in other mineralized cranial elements, except for the otoliths. Also, mineralization seems to occur left-right independently, matching earlier observations of such an independency of the opercular phenotype as a whole. This study confirms that a quantitative characterization of BMD patterns in 3D is feasible, even in smaller specimens, and that it has several advantages over other commonly used approaches.

Screening for osteogenic activity in extracts from Irish marine organisms: The potential of Ceramium pallidum.

Extracts and compounds derived from marine organisms have reportedly shown some osteogenic potential. As such, these bioactives may aid in the treatment of musculoskeletal conditions such as osteoporosis; helping to address inefficacies with current treatment options. In this study, 72 fractions were tested for their in vitro osteogenic activity using a human foetal osteoblast (hFOB) cell line and bone marrow derived mesenchymal stem cells (MSCs), focusing on their cytotoxic, proliferative and differentiation effects. Extracts dissolved in dimethyl sulfoxide and ethanol showed no significant osteogenic potential. However, two extracts derived from powder residues (left over from original organic extractions) caused a significant promotion of MSC differentiation. Bioactivity from powder residues derived from the epiphytic red algae Ceramium pallidum is described in detail to highlight its treatment potential. In vitro, C. pallidum was shown to promote MSC differentiation and extracellular matrix mineralisation. In vivo, this extract caused a significant increase in opercular bone growth of zebrafish larvae and a significant increase in bone density of regenerated adult caudal fins. Our findings therefore show the importance of continued screening efforts, particularly of novel extract sources, and the presence of bioactive compounds in C. pallidum extract.

Personal adornments in the Romanian Eneolithic: Local versus exotic raw materials

Prehistoric personal adornments have benefited from detailed studies because they are an inexhaustible source of reflection. From these objects can be identified the symbolic and religious behaviour of prehistoric groups; they may also reflect the socio-economic aspects of these communities and may even serve as markers of cultural boundaries and exchange networks in prehistory. Appreciating the considerable potential of personal adornments, the central purpose of this study is to analyse and compare the types of ornaments used by Eneolithic communities (c. 5000-3500 BC) in the area to the north of the Danube, to provide an integrated image on the ways in which the use of certain types of ornaments had socio-economic effects. Among local species, the shells of Lithoglyphus sp. gastropod were used to make bracelets and necklaces and the valves of Unio sp. were processed into small circular beads. Alsoidentified were beads made of Cyprinus carpio opercular bones, a unique find for this stage of European prehistory. Exotic raw materials are represented by various forms of Spondylus adornments, bracelets of Glycymeris valve or tubular beads of scaphopod shells. While in the first case, we have identified pieces in various processing stages, from entire valves, shells or bones, simply perforated, and irregular fragments, to finished beads, used as decorative objects – certainly processed in situ; the artefacts of exotic raw materials arrived at the communities north of the Danube in a finished form, as a result of inter-community exchanges. Very interesting is the fact that the ornaments of exotic raw materials (e. g., Spondylus sp., Glycymeris sp., Antalis sp.) were identified mainly in funerary contexts and less in settlements, proving they were prestige goods and accompanying the deceased to "the other world". Therefore, it seems, apparently depending on the local or exotic origin of the raw material, that these personal adorments had differing socio-economic meanings.

Red algal extracts from Plocamium lyngbyanum and Ceramium secundatum stimulate osteogenic activities in vitro and bone growth in zebrafish larvae

Through the current trend for bioprospecting, marine organisms - particularly algae - are becoming increasingly known for their osteogenic potential. Such organisms may provide novel treatment options for osteoporosis and other musculoskeletal conditions, helping to address their large healthcare burden and the limitations of current therapies. In this study, extracts from two red algae – Plocamium lyngbyanum and Ceramium secundatum – were tested in vitro and in vivo for their osteogenic potential. In vitro, the growth of human bone marrow stromal cells (hBMSCs) was significantly greater in the presence of the extracts, particularly with P. lyngbyanum treatment. Osteogenic differentiation was promoted more by C. secundatum (70 µg/ml), though P. lyngbyanum had greater in vitro mineralisation potential. Both species caused a marked and dose-dependent increase in the opercular bone area of zebrafish larvae. Our findings therefore indicate the presence of bioactive components in P. lyngbyanum and C. secundatum extracts, which can promote both in vitro and in vivo osteogenic activity.