Calcareous Plates Research Articles

Phagocytosis in Marine Coccolithophore Gephyrocapsa huxleyi: Comparison between Calcified and Non-Calcified Strains.

Coccolithophores play a significant role in marine calcium carbonate production and carbon cycles, attributing to their unique feature of producing calcareous plates, coccoliths. Coccolithophores also possess a haplo-diplontic life cycle, presenting distinct morphology types and calcification states. However, differences in nutrient acquisition strategies and mixotrophic behaviors of the two life phases remain unclear. In this study, we conducted a series of phagocytosis experiments of calcified diploid and non-calcified haploid strains of coccolithophore Gephyrocapsa huxleyi under light and dark conditions. The phagocytosis capability of each strain was examined based on characteristic fluorescent signals from ingested beads using flow cytometry and fluorescence microscopy. The results show a significantly higher phagocytosis percentage on fluorescent beads in the bacterial prey surrogates of the non-calcified haploid Gephyrocapsa huxleyi strain, than the calcified diploid strain with or without light. In addition, the non-calcified diploid cells seemingly to presented a much higher phagocytosis percentage in darkness than under light. The differential phagocytosis capacities between the calcified diploid and non-calcified haploid Gephyrocapsa huxleyi strains indicate potential distinct nutritional strategies at different coccolithophore life and calcifying stages, which may further shed light on the potential strategies that coccolithophore possesses in unfavorable environments such as twilight zones and the expanding coccolithophore niches in the natural marine environment under the climate change scenario.

Superficial Calcified Plates Associated to Plaque Erosions in Acute Coronary Syndromes.

This study investigates the clinical relevance and therapeutic implications of the OCT identification of intracoronary superficial calcified plates (SCPs) in acute coronary syndromes (ACSs). In 70 consecutive ACS patients (pts), we studied the three main underlying ACS mechanisms: plaque erosion (PE), plaque rupture and eruptive calcified nodule (CN). The PE lesions, occurring on an intact fibrous cap overlying a heterogeneous substrate, were identified in 12/70 pts (17.1%). PE on superficial calcified plates (PE-SCP) represented 58.3% of the PE lesions (7/12 pts) and had a 10% overall incidence in the culprit lesions (7/70 pts). PE-SCP lesions occurred mostly on the left anterior descending artery, correlated with white thrombi (85.7%) and had a proximal intraplaque site (71.4%). PE-SCP lesions were treated conservatively, as nonsignificant lesions, in 4/7 pts. Our study emphasizes that the coronary calcium-related ACS risk is not only associated with the spotty calcifications or CN but also with the PE-SCP lesions.

Structure and Composition of the Cuticle of the Goose Barnacle Pollicipes pollicipes: A Flexible Composite Biomaterial.

Arthropods, the largest animal phylum, including insects, spiders and crustaceans, are characterized by their bodies being covered primarily in chitin. Besides being a source of this biopolymer, crustaceans have also attracted attention from biotechnology given their cuticles' remarkable and diverse mechanical properties. The goose barnacle, Pollicipes pollicipes, is a sessile crustacean characterized by their body parts covered with calcified plates and a peduncle attached to a substrate covered with a cuticle. In this work, the composition and structure of these plates and cuticle were characterized. The morphology of the tergum plate revealed a compact homogeneous structure of calcium carbonate, a typical composition among marine invertebrate hard structures. The cuticle consisted of an outer zone covered with scales and an inner homogenous zone, predominantly organic, composed of successive layers parallel to the surface. The scales are similar to the tergum plate and are arranged in parallel and oriented semi-vertically. Structural and biochemical characterization confirmed a bulk composition of ɑ-chitin and suggested the presence of elastin-based proteins and collagen. The mechanical properties of the cuticle showed that the stiffness values are within the range of values described in elastomers and soft crustacean cuticles resulting from molting. The removal of calcified components exposed round holes, detailed the structure of the lamina, and changed the protein properties, increasing the rigidity of the material. This flexible cuticle, predominantly inorganic, can provide bioinspiration for developing biocompatible and mechanically suitable biomaterials for diverse applications, including in tissue engineering approaches.

Ediacaran Corumbella has a cataphract calcareous skeleton with controlled biomineralization.

Corumbella is a terminal Ediacaran tubular, benthic fossil of debated morphology, composition, and biological affinity. Here, we show that Corumbella had a biomineralized skeleton, with a bilayered construction of imbricated calcareous plates and rings (sclerites) yielding a cataphract organization, that enhanced flexibility. Each sclerite likely possessed a laminar microfabric with consistent crystallographic orientation, within an organic matrix. Original aragonitic mineralogy is supported by relict aragonite and elevated Sr (mean= ca. 11,800 ppm in central parts of sclerites). In sum, the presence of a polarisation axis, sclerites with a laminar microfabric, and a cataphract skeletal organization reminiscent of early Cambrian taxa, are all consistent with, but not necessarily indicative of, a bilaterian affinity. A cataphract skeleton with an inferred complex microstructure confirms the presence of controlled biomineralization in metazoans by the terminal Ediacaran, and offers insights into the evolution of development and ecology at the root of the 'Cambrian radiation'.

Lost and found: Totton’s Minyaspis faroni revived and molecular evidence of paraphyly of Oxynaspis and Minyaspis

ABSTRACT The stalked barnacles Minyaspis faroni associated with antipatharians known from the southern Red Sea have been recently recorded in the northern Red Sea. Two genera of oxynaspids, Oxyaspis and Minyaspis, differ morphologically in the coverage of the capitulum. In Oxyaspis, the capitulum is covered by calcified plates, whereas in Minyaspis, the plates are reduced, and there is an uncalcified area between plates. Molecular analyses revealed that species with reduced plates do not cluster in the same clade, whereas species with full coverage and uncalcified capitula are found in the same clade. Our analysis indicates that the reduction of opercular plates in the epibiotic barnacles has occurred more than once in the barnacle evolutionary pathway. The reduction in shell plates’ number, size, shape and thickness is an adaptive character of epibiotic symbiosis. This mode of life, common in thoracican barnacles, leads to adaptive morphological changes. Hence, the morphology of shell plates is not a homologous feature but reflects parallel evolution.

Strain-specific morphological response of the dominant calcifying phytoplankton species Emiliania huxleyi to salinity change.

The future physiology of marine phytoplankton will be impacted by a range of changes in global ocean conditions, including salinity regimes that vary spatially and on a range of short- to geological timescales. Coccolithophores have global ecological and biogeochemical significance as the most important calcifying marine phytoplankton group. Previous research has shown that the morphology of their exoskeletal calcified plates (coccoliths) responds to changing salinity in the most abundant coccolithophore species, Emiliania huxleyi. However, the extent to which these responses may be strain-specific is not well established. Here we investigated the growth response of six strains of E. huxleyi under low (ca. 25) and high (ca. 45) salinity batch culture conditions and found substantial variability in the magnitude and direction of response to salinity change across strains. Growth rates declined under low and high salinity conditions in four of the six strains but increased under both low and high salinity in strain RCC1232 and were higher under low salinity and lower under high salinity in strain PLYB11. When detailed changes in coccolith and coccosphere size were quantified in two of these strains that were isolated from contrasting salinity regimes (coastal Norwegian low salinity of ca. 30 and Mediterranean high salinity of ca. 37), the Norwegian strain showed an average 26% larger mean coccolith size at high salinities compared to low salinities. In contrast, coccolith size in the Mediterranean strain showed a smaller size trend (11% increase) but severely impeded coccolith formation in the low salinity treatment. Coccosphere size similarly increased with salinity in the Norwegian strain but this trend was not observed in the Mediterranean strain. Coccolith size changes with salinity compiled for other strains also show variability, strongly suggesting that the effect of salinity change on coccolithophore morphology is likely to be strain specific. We propose that physiological adaptation to local conditions, in particular strategies for plasticity under stress, has an important role in determining ecotype responses to salinity.

The first report of Asterodiscides fourmanoiri (Echinodermata: Asteroidea) from the North Coast of Oman Sea, Iran.

Echinoderms with around 7,000 species can be found at all depths of the marine ecosystems. Body shape is radially symmetrical, covered by calcareous plates and five body parts are around a central axis. The class of Asteroidea (also known as starfish or sea star) is one of the most diverse groups within the phylum Echinodermata, including nearly 1900 extant species grouped into 36 families, and approximately 370 extant genera (Blake and Mah, 2014). They generally have a central disc from which radiate five arms. The aboral disk surface (the top surface opposite the mouth) could be smooth and leathery, granular, spiny, and is coated with different plates (Lambert, 2000). Many species found in a variety of colors such as red, orange, blue, grey or brown (O’Loughlin et al., 2003).

RECORD OF THE BARNACLE OCTOLASMISANGULATA (AURIVILLIUS, 1894) FROM THE GILLS OF THE CRAB PORTUNUS SEGNIS (FORSKÅL, 1775) OF IRAQI MARINE WATERS

Ten blue swimming crabs Portunus segnis (Forskal, 1775) were collected from the north west of the Arabian Gulf off the Iraqi marine waters from October to November 2017 at 29ᵒ 37′ N to 48ᵒ 47′ E. The barnacle Octolasmis angulata (Aurivillius, 1894) was found on the gills of the present species of crab, the mean incidence of infestation was 30%, while the mean Intensity of infestation was 12.3. The barnacle have a long and slim shaped calcareous plate with the presence of carina and the absence of tergum, in addition to the elongated shape of carina and scutum. The current study represents the first record of the barnacle O. angulata in the Arabian Gulf.

Abstract WMP39: Laser Angioscopy in Carotid Artery Disease: Imaging Findings and Histopathological Correlation

Our understanding and management of carotid artery disease has largely relied on angiography, US and MR. However, existing modalities cannot accurately identify the spectrum of thrombogenic lesions on the vascular surface or reliably detect structural markers of instability. Thus, the natural history of the different histopathological hallmarks of advanced or complicated plaques is unknown, and many patients with culprit substenotic plaques are misdiagnosed with cryptogenic stroke. An intraluminal approach to directly inspect the endovascular surfaces at unprecedented resolutions would enable detailed structural analysis of carotid plaques and the identification of the root cause of carotid-related strokes. A scanning fiber angioscope (SFA), a high-definition 1.2-mm forward-viewing camera that generates videos by spirally scanning low-power laser beams, was developed for clinical use and employed to analyze the endovascular surfaces of ex vivo human carotid arteries (n=95) and endarterectomized plaques (n=20). Specimens were then imaged with US and micro-CT, and all vascular diagnostic tests obtained in the patients undergoing carotid revascularization were accessed. Imaging findings in the vascular surfaces were then validated by histomorphological analysis of >300 lesions, and an angioscopic classifier for atherosclerosis was generated. Full-color videos at 30Hz and at a resolution >200,000 pixels were generated from the entire endovascular circumference in all specimens with depth-of-focus larger than 5cm in saline solution. The ability to analyze the surface anatomy with unparalleled detail allowed the identification of early, intermediate, advanced and complex atherosclerotic lesions, including ulceration of fibrotic cap, excavation of the necrotic core leading to pseudolumens, intimal flaps, exposed necrotic core to the lumen, erosions, recent and remote intimal hemorrhages, luminal thrombus, eruptive calcified nodules and calcified intimal sheaths and plates. SFA offers a direct view of the endoluminal surfaces with unparalleled resolution and has the potential to revolutionize research, diagnosis, prognosis and image-guided therapy in carotid atherosclerosis.

Chronic Kidney Disease Is Linked to Carotid Nodular Calcification, An Unstable Plaque Not Correlated to Inflammation.

The incidence and the different type of carotid calcifications, nodular and non-nodular, and their role in the acute cerebrovascular disease has not yet been defined. Various studies have correlated the presence of specific risk factors, in particular the chronic kidney disease, with the presence of calcification, but not with the type of calcification. Since it is likely that carotid nodular calcifications rather than those with non-nodular aspect may represent a plaque at high risk of rupture, the purpose of our study was to evaluate the role of nodular calcification in the pathogenesis of cerebrovascular syndromes and their possible correlation with specific risk factors. A total of 168 carotid plaques from symptomatic and asymptomatic patients submitted to endarterectomy, whom complete clinical and laboratory assessment of major cardiovascular risk factors was available, were studied. In 21 endarterectomies (5 from symptomatic and 16 from asymptomatic patients) an eruptive calcified nodule, consisting of calcified plates associated to a small amount of fibrous tissue without extracellular lipids and inflammatory cells, was found protruding into the lumen. Nodular calcifications were significantly observed in patients affected by chronic kidney disease (with GFR<60 ml / min / 1.73 m2), with a normal lipidic and glycemic profile. On the contrary, non-nodular calcification, mainly correlated to diabetes, were stable lesions. Results of our study suggest that the mechanisms and the clinical significance of carotid atherosclerotic calcification may be different. The nodular calcification could represent a type of unstable plaque, significantly related to chronic kidney disease, without inflammation, morphologically different from the classical vulnerable plaques.

Aortic homograft replacement in a patient with a porcelain aorta: A case report

Patients with a severely calcified (porcelain) aorta are often unsuitable candidates for cardiac surgery because of the high risk of neuroembolic complications from loose calcified particles.We describe a surgical technique in a patient with a porcelain aorta undergoing an aortic homograft replacement for infective endocarditis that used an oscillating saw and a surgical hand drill for suturing the calcified plates.

New Insights onXylopholas(Mollusca: Xylophagaidae): Diversity, Growth and Reproduction

Abstract: Deep-sea wood-boring bivalves of the genus Xylopholas Turner, 1972 are unified by a plate-like elaboration lateral to the siphon tips; this genus, known only from specimens under 4 mm in shell length, may provide essential clues to the group's phylogeny. Here three aspects of their biology are treated. A new species, Xylopholas dostwous sp. nov., is distinguished by the absence of a siphonal collar, gills that extend into the incurrent siphon, a curved posterior valve margin and a fleshy cover over the anterior adductors. Second, specimens nearly eight times larger than any in the type series of X. crooki Voight, 2007 show strong positive allometry of the fleshy Anterior Adductor Cover, forcing a reconsideration of the mesoplax (calcified plates over the anterior adductor muscle). Third, apparent dwarf males of Xylopholas may fuse with the female's mantle, allowing sperm to be released inside the mantle near the oviducts. Dramatic differences among hypothesized dwarf xylophagaid males suggest ma...

Skeleton growth under uniformly distributed force conditions: producing spherical sea urchins

AbstractSea urchin skeletons, or tests, comprise rigid calcareous plates, interlocked and sutured together with collagen fibres. The tests are malleable due to mutability in the collagen fibres that loosen during active feeding, yielding interplate gaps. We designed an extraterrestrial simulation experiment wherein we subjected actively growing sea urchins toone factorassociated with zero-gravity environments, by growing them under conditions in which reactionary gravitational forces were balanced, and observed how their tests responded. Preventing tests from adhering to surfaces during active growth produced more-spherical bodies, realized as increased height-to-diameter ratios. Sea urchin tests constitute ideal systems for obtaining data that could be useful in extraterrestrial biology research, particularly in how skeletons grow under altered-gravity conditions.

Ex vivo comparison of angioscopy and histopathology for the evaluation of coronary plaque characteristics

The yellow plaque has been considered to be a vulnerable and high risk for acute coronary syndrome events but not fully evaluated. The aim of this study was to evaluate the relationship between angioscopic color grade and histological features in coronary autopsy specimens. We longitudinally sectioned 110 coronary arteries from 40 autopsy hearts with non-cardiovascular death. Harvested arteries were imaged with intravascular ultrasound to identify the focal plaque (plaque burden >50%). An angioscopic examination of each focal plaque evaluated its color intensity as follows: 0 (white), 1 (light yellow), 2 (yellow), or 3 (dark yellow). The corresponding histological assessment was classified according to a modified version of the American Heart Association classification of atherosclerosis. Two hundred six plaques were matched to the histological analysis. Of these, 82 (40%) were categorized as yellow (≥grade 1). Although, yellow plaque often includes thin-cap fibroatheroma (TCFA), the sensitivity, specificity, positive predictive value, negative predictive value, and overall diagnostic accuracy for histological TCFA were 83, 91, 22, 99 and 91%, respectively. The false-positive coronary angioscopic diagnoses for TCFA that contributed to the low positive predictive value consisted of the following plaques: thick FA (>65μm), accumulations of large quantities of foam cells on the luminal surface, or dense calcified plates at the surface of the intima. Vulnerable coronary plaques were detected with high sensitivity and low positive predictive value from their yellow color on angioscopy. Not only fibroatheroma but also various types of plaques and their components, such as immature lipidic components and superficial calcium plates, appeared yellow on coronary angioscopy.

Quantitative Analysis of Carbon Flow into Photosynthetic Products Functioning as Carbon Storage in the Marine Coccolithophore, Emiliania huxleyi

The bloom-forming coccolithophore Emiliania huxleyi (Haptophyta) is a dominant marine phytoplankton, cells of which are covered with calcareous plates (coccoliths). E. huxleyi produces unique lipids of C37–C40 long-chain ketones (alkenones) with two to four trans-unsaturated bonds, β-glucan (but not α-glucan) and acid polysaccharide (AP) associated with the morphogenesis of CaCO3 crystals in coccoliths. Despite such unique features, there is no detailed information on the patterns of carbon allocation into these compounds. Therefore, we performed quantitative estimation of carbon flow into various macromolecular products by conducting 14C-radiotracer experiments using NaH14CO3 as a substrate. Photosynthetic 14C incorporation into low molecular-mass compounds (LMC), extracellular AP, alkenones, and total lipids except alkenones was estimated to be 35, 13, 17, and 25 % of total 14C fixation in logarithmic growth phase cells and 33, 19, 18, and 18 % in stationary growth phase cells, respectively. However, less than 1 % of 14C was incorporated into β-glucan in both cells. 14C-mannitol occupied ca. 5 % of total fixed 14C as the most dominant LMC product. Levels of all 14C compounds decreased in the dark. Therefore, alkenones and LMC (including mannitol), but not β-glucan, function in carbon/energy storage in E. huxleyi, irrespective of the growth phase. Compared with other algae, the low carbon flux into β-glucan is a unique feature of carbon metabolism in E. huxelyi.Electronic supplementary materialThe online version of this article (doi:10.1007/s10126-015-9632-1) contains supplementary material, which is available to authorized users.

Anal sac of a cladid crinoid from Permo-Carboniferous Talchir Formation, Talchir basin, Odisha

A calcareous anal sac of a probable cladid crinoid, referable to Cyathocrinitacea family is reported for the first time from late Carboniferous-early Permian siliciclastics of Talchir basin, Angul district, Odisha. A cladid affinity for this crinoid specimen is confirmed from tubular, anteriorly tapered anal sac with slightly alternating, multiple rows of calcified plates, hexagonal or modified hexagonal, pentagonal and polygonal plate sutures with pitted plate surface. Generic identification is not attempted due to the incomplete preservation of the specimen. The preservation of this exclusive marine organism in the fine siliciclastics attests to a marine depositional milieu.

外来種ナンオウフジツボ&lt;i&gt;Perforatus perforatus&lt;/i&gt;の北九州市洞海湾における1992年の発見は東アジア初記録

Perforatus perforatus was originally distributed from England to the Mediterranean and West Africa. It was first reported from the East Asia following its discovery in three ports near Ulsan Port, Korea, on 24 June 2006 and some other ports along the southeast coast of Korea. In Japan, this species was first reported on the basis of specimens collected at 2012 from buoys for the cultivation of rock-oysters, and thereafter was found to be widely distributed in northern Honshu. Here we re-identify as Perforatus perforatus a Japanese specimen that had been collected on 11 May 1992 from the Dokai Bay of Kitakyushu in northern Kyushu. We also provide photographs of its calcareous plates. This specimen represents the oldest record of P. perforatus from the East Asia and thereby provides an excellent example of the importance of the preservation of historical collections and preserved in the Kitakyushu Museum of Natural History and Human History, Kitakyushu, Fukuoka, Japan (KMNH IvR 500844).

Chemical Offense by Means of Toxicysts in the Freshwater Ciliate, Coleps hirtus

Coleps hirtus is a small common freshwater ciliate belonging to the protostomatid group, its body covered by calcified plates assembled to form an armor. Coleps feeds on bacteria, algae, flagellates, living and dead ciliates, animal and plant tissues. To assist its carnivorous feeding the ciliate is equipped with offensive extrusomes (toxicysts), clustering mainly in and around its oral aperture. In this study, we isolated the discharge of the toxicysts from living cells, evaluating its cytotoxic effects against various ciliate species, and demonstrating that it is essential for the effectiveness of Coleps' predatory behavior. The analysis of the toxicyst discharge performed by liquid chromatography-electrospray-mass spectrometry and gas chromatography-mass spectrometry, revealed the presence of a mixture of 19 saturated, monounsaturated and polyunsaturated free fatty acids with the addition of a minor amount of a diterpenoid (phytanic acid).

Present Distribution Of Pedunculate Barnacle Of Wild Mud Crab Scylla Olivacea From Setiu Wetland, Terengganu Coastal Water, Malaysia

Pedunculate, Goose or Stalked barnacles are commonly found in the hard substrate of marine or brackish area and it also recorded found attached on the living organisms as their host. Thirty seven wild mud crabs (Scylla olivacea) were sampled from Setiu Wetland (5°40’47.93”N, 102°42’45.04”E), Terengganu, Malaysia. The 625 sample of barnacles were collected and the samples were preserved in 70% alcohol and observed by using Table Top Scanning Electron Microscope (Hitachi TM1000). The morphology and characteristic of the barnacle were recorded based on the observation of their peduncle, capitulum, calcareous plates, carina, tergum and branched scutum. To our knowledge, there is no morphological study about the species of pedunculate barnacle that attached on gill of S. olivacea in Malaysia. Thus, this study provides the first report of pedunculate barnacle attached on S. olivacea in the east coast of peninsular Malaysia.

Aluminum inhibits the growth of hydroxyapatite crystals developed on a biomimetic methacrylic polymer

ProjectAluminum (Al) is an increasing problem in biomedicine since it can interact with phosphates. Bone is one of the preferential target tissues of Al deposition: Al interacts with mineralization and/or bone cell activities. We searched the influence of Al deposition in hydroxyapatite developed on a biomimetic polymer (carboxymethylated poly(2-hydroxyethyl-methacrylate)) which mimics bone mineralization in the absence of cells. ProceduresPellets of polymer were incubated for 5 days in a synthetic body fluid (SBF) to induce mineralization, then 21 days in SBF containing 20, 40 and 60μg/L Al3+. Other pellets were incubated in SBF containing commercial Al foil (33mg/vial) either in 1, 2 or 6 pieces. The mineral deposits were dissolved in HCl and Ca2+, PO43− and Al3+ content was measured. Hydroxyapatite was characterized by SEM and X energy-dispersive X-ray analysis (EDX). ResultsThe amount of Al3+ was dose-dependently increased in Ca/P deposits on the polymer pellets. At high concentration (or with the 6 Al foils) growth of hydroxyapatite calcospherite was inhibited; only calcified plates emerging from the polymer were observed. Pellets incubated with 1 and 2 Al foils exhibited a reduction in calcospherite diameter and an increase in the Al3+/Ca2+ ratio. EDX identified Al in the mineral deposits. ConclusionsIn this acellular model, Al3+ altered the growth of calcospherites at low concentration and inhibited their development at high concentration. In SBF, a release of Al3+ from aluminum foils also inhibited mineralization. This study emphasizes the importance of Al in bone pathology and stresses the question of its release from biomaterials.