The sterols of echinoderms

1972 ◽  
Vol 180 (1059) ◽  
pp. 223-246 ◽  
Keyword(s):  
Phylogenetic Relationships ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Point Of View ◽  
Biological Origin ◽  
Sea Cucumbers ◽  
Biochemical Evidence ◽  
Modern Methods ◽  
Close Relationship ◽  
The One

The pioneering work of Bergmann and his colleagues demonstrated that marine invertebrates in many cases contain complex sterol mixtures consisting of C 27 , C 28 and C 29 sterols of varying degrees of unsaturation (Bergmann 1949, 1962). The sterols found in the phylum Echinodermata have proved of particular interest not only from the point of view of their composition and biological origin but also from phylogenetic considerations. Dorée (1909) first recognized that the sterol of a starfish differed from cholesterol, the typical sterol of higher animals. Later Kossel & Edlbacher (1915) obtained the sterol from a starfish, Asteropecten aurantiacus , and named it stellasterol. Subsequently Bergmann & Stansbury (1944) concluded that starfish sterols are mixtures which include stellastenol (1) and stellasterol, the 22, 23-dihydro derative of stellastenol (Shoppee 1964) Extending their studies Bergmann and co-workers demonstrated that the echinoderms can be divided into two groups on the basis of the types of sterol which they contain. Crinoidea (sea lilies), Ophiuroidea (brittle stars) and Echinoidea (sea urchins) contain sterols with a ∆ 5 bond while the Asteroidea (starfish) and Holothuroidea (sea cucumbers) contain mixtures in which sterols with a ∆ 7 bond predominate (Bergmann 1962). This division of echinoderms according to sterol type has recently been confirmed by Gupta & Scheuer (1968) using more modern methods of sterol analysis. Bergmann (1962) concluded that the distribution of ∆ 5 and ∆ 7 sterols in the different classes of echinoderms is a reflexion of the phylogenetic relationships which exist in the phylum. From embryological evidence there is a close relationship between the asteroids and holothuroids on the one hand and the ophiuroids and echinoids on the other (Bergmann 1962; Hyman 1955). In addition to the data on sterols other comparative biochemical evidence on the occurrence and distribution of batyl alcohol, spinochromes and phosphagens in echinoderms is in accord with these phylogenetic relationships (Singh, Moore & Scheuer 1967; Bolker 1967 α ). The validity of the embryological and biochemical evidence, however, has been contested by Fell who regards the asteroids to be more closely related to the ophiuroids while the holothuroids have some affinities with the echinoids (Fell 1948, 1963, 1965; Fell & Pawson 1966; Bolker 1967 α ).

Phylogenetic relationships of extant echinoderm classes

2001 ◽  
Vol 79 (7) ◽  
pp. 1232-1250 ◽  
Author(s):  
Daniel Janies
Keyword(s):  
Phylogenetic Relationships ◽  
Sea Urchins ◽  
Strong Support ◽  
Sensitivity Analyses ◽  
Molecular Evidence ◽  
Evolutionary Models ◽  
Sea Cucumbers ◽  
Computational Approaches ◽  
Evidential Value ◽  
Nuclear Loci

A well-supported phylogeny of echinoderm classes has eluded morphological, embryological, molecular, and combined analyses. From this body of work it is apparent that (i) echinoids (sea urchins) and holothuroids (sea cucumbers) are related, and (ii) crinoids (sea lilies) are the sister taxon to extant eleutherozoan classes (asteroids, ophiuroids, echinoids, and holothuroids). However, the relationships of asteroids and ophiuroids to other echinoderm classes have been difficult to recover. To address relationships between the asteroids and ophiuroids and other echinoderms, I have sequenced additional nuclear loci and taxa and used novel computational approaches for co-optimizing morphological with molecular evidence at the level of sequence alignment. Support for the monophyly of each class is strong. Support for a monophyletic Asteroidea + Xyloplax is as strong as for Asteroidea. Support for Asterozoa (Asteroidea + Ophiuroidea) is apparent, albeit not as strong as for other clades (e.g., Echinozoa, Eleutherozoa, and Echinodermata). I also present detailed sensitivity analyses to provide (i) a test of the monophyly of groups under a variety of evolutionary models and (ii) a statement of the evidential value of various character systems.

scholarly journals Chemosensitivity in the Sea Urchin Paracentrotus lividus (Echinodermata: Echinoidea) to Food-Related Compounds: An Innovative Behavioral Bioassay

2021 ◽  
Vol 9 ◽  
Author(s):  
Paolo Solari ◽  
Viviana Pasquini ◽  
Marco Secci ◽  
Angelica Giglioli ◽  
Roberto Crnjar ◽  
...  
Keyword(s):  
Sea Urchin ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Paracentrotus Lividus ◽  
Arthrospira Platensis ◽  
Point Of View ◽  
Dependent Manner ◽  
Chemical Sensitivity ◽  
Blue Green Algae ◽  
Related Compounds

Like other animals, echinoderms rely on chemical senses to detect and localize food resources. Here, we evaluate the chemical sensitivity of the sea urchin Paracentrotus lividus to a number of stimuli possibly related to food, such as a few sugars, compared to the blue-green algae Spirulina (Arthrospira platensis). To do this we developed a simple, innovative method based on the recording of “urchinograms” estimating the movements of spines, pedicellariae, tube feet, and eventually of the whole sea urchin, in response to chemicals, while keeping both the whole animal and the stimulus in their natural environment, underwater. Our results show that Spirulina is a highly stimulating compound for the sea urchin, by acting in a dose-dependent manner. The animals resulted also sensitive, even if to a lesser extent, to some sugars, such as the monosaccharide glucose, but not to its isomer fructose, while among disaccharides, they sensed cellobiose, but not sucrose or trehalose. From an applied point of view, any insight into the chemical sensitivity of sea urchins toward potential food-related compounds may lead to the discovery of key chemicals that would help improve the efficiency and reduce the costs of dietary substrates for optimization of intensive rearing strategies. Although this method has been developed for P. lividus, it will be suitable to evaluate the chemical sensitivity of other echinoderms and other marine invertebrates characterized by low mobility.

scholarly journals Triterpenoids in Echinoderms: Fundamental Differences in Diversity and Biosynthetic Pathways

Marine Drugs ◽  
2019 ◽  
Vol 17 (6) ◽  
pp. 352 ◽  
Author(s):  
Emily J. S. Claereboudt ◽  
Guillaume Caulier ◽  
Corentin Decroo ◽  
Emmanuel Colson ◽  
Pascal Gerbaux ◽  
...  
Keyword(s):  
Defense Mechanism ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Animal Kingdom ◽  
Sea Stars ◽  
Sea Cucumbers ◽  
Specific Chemical ◽  
Chemical Signatures ◽  
Triterpenoid Glycosides ◽  
Self Protection

Echinoderms form a remarkable phylum of marine invertebrates that present specific chemical signatures unique in the animal kingdom. It is particularly the case for essential triterpenoids that evolved separately in each of the five echinoderm classes. Indeed, while most animals have Δ5-sterols, sea cucumbers (Holothuroidea) and sea stars (Asteroidea) also possess Δ7 and Δ9(11)-sterols, a characteristic not shared with brittle stars (Ophiuroidea), sea urchins (Echinoidea), and crinoids (Crinoidea). These particular Δ7 and Δ9(11) sterols emerged as a self-protection against membranolytic saponins that only sea cucumbers and sea stars produce as a defense mechanism. The diversity of saponins is large; several hundred molecules have been described in the two classes of these saponins (i.e., triterpenoid or steroid saponins). This review aims to highlight the diversity of triterpenoids in echinoderms by focusing on sterols and triterpenoid glycosides, but more importantly to provide an updated view of the biosynthesis of these molecules in echinoderms.

Skeletal elements of crinoid echinoderms: High-resolution structural and microanalytical results

1983 ◽  
Vol 41 ◽  
pp. 194-195
Author(s):  
D. F. Blake ◽  
L. F. Allard ◽  
D. R. Peacor
Keyword(s):  
High Resolution ◽  
Marine Invertebrates ◽  
Sea Urchins ◽  
Structural Features ◽  
Sea Stars ◽  
High Resolution Tem ◽  
Relationship Of ◽  
The Relationship ◽  
Insight Into

Echinodermata is a phylum of marine invertebrates which has been extant since Cambrian time (c.a. 500 m.y. before the present). Modern examples of echinoderms include sea urchins, sea stars, and sea lilies (crinoids). The endoskeletons of echinoderms are composed of plates or ossicles (Fig. 1) which are with few exceptions, porous, single crystals of high-magnesian calcite. Despite their single crystal nature, fracture surfaces do not exhibit the near-perfect {10.4} cleavage characteristic of inorganic calcite. This paradoxical mix of biogenic and inorganic features has prompted much recent work on echinoderm skeletal crystallography. Furthermore, fossil echinoderm hard parts comprise a volumetrically significant portion of some marine limestones sequences. The ultrastructural and microchemical characterization of modern skeletal material should lend insight into: 1). The nature of the biogenic processes involved, for example, the relationship of Mg heterogeneity to morphological and structural features in modern echinoderm material, and 2). The nature of the diagenetic changes undergone by their ancient, fossilized counterparts. In this study, high resolution TEM (HRTEM), high voltage TEM (HVTEM), and STEM microanalysis are used to characterize tha ultrastructural and microchemical composition of skeletal elements of the modern crinoid Neocrinus blakei.

Understanding functional illiteracy from a policy, adult education, and cognition point of view: Towards a joint referent framework

2019 ◽  
Vol 30 (2) ◽  
pp. 109-122
Author(s):  
Aleksandar Bulajić ◽  
Miomir Despotović ◽  
Thomas Lachmann
Keyword(s):  
Adult Education ◽  
Operational Definition ◽  
Literacy Skills ◽  
Point Of View ◽  
Industrialized Countries ◽  
Functional Illiteracy ◽  
Scale Levels ◽  
Components Of Reading ◽  
The One ◽  
Definition Of

Abstract. The article discusses the emergence of a functional literacy construct and the rediscovery of illiteracy in industrialized countries during the second half of the 20th century. It offers a short explanation of how the construct evolved over time. In addition, it explores how functional (il)literacy is conceived differently by research discourses of cognitive and neural studies, on the one hand, and by prescriptive and normative international policy documents and adult education, on the other hand. Furthermore, it analyses how literacy skills surveys such as the Level One Study (leo.) or the PIAAC may help to bridge the gap between cognitive and more practical and educational approaches to literacy, the goal being to place the functional illiteracy (FI) construct within its existing scale levels. It also sheds more light on the way in which FI can be perceived in terms of different cognitive processes and underlying components of reading. By building on the previous work of other authors and previous definitions, the article brings together different views of FI and offers a perspective for a needed operational definition of the concept, which would be an appropriate reference point for future educational, political, and scientific utilization.

Use of a Lyophilized Reference Plasma to Compare Coagulation Test Procedures

1975 ◽  
Vol 34 (02) ◽  
pp. 426-444 ◽  
Author(s):  
J Kahan ◽  
I Nohén
Keyword(s):  
Oral Anticoagulant Therapy ◽  
Repeated Measurements ◽  
Test Procedures ◽  
Coagulation Activity ◽  
Close Relationship ◽  
Measured Activity ◽  
Test Materials ◽  
The Difference ◽  
The Stability ◽  
The One

SummaryIn 4 collaborative trials, involving a varying number of hospital laboratories in the Stockholm area, the coagulation activity of different test materials was estimated with the one-stage prothrombin tests routinely used in the laboratories, viz. Normotest, Simplastin-A and Thrombotest. The test materials included different batches of a lyophilized reference plasma, deep-frozen specimens of diluted and undiluted normal plasmas, and fresh and deep-frozen specimens from patients on long-term oral anticoagulant therapy.Although a close relationship was found between different methods, Simplastin-A gave consistently lower values than Normotest, the difference being proportional to the estimated activity. The discrepancy was of about the same magnitude on all the test materials, and was probably due to a divergence between the manufacturers’ procedures used to set “normal percentage activity”, as well as to a varying ratio of measured activity to plasma concentration. The extent of discrepancy may vary with the batch-to-batch variation of thromboplastin reagents.The close agreement between results obtained on different test materials suggests that the investigated reference plasma could be used to calibrate the examined thromboplastin reagents, and to compare the degree of hypocoagulability estimated by the examined PIVKA-insensitive thromboplastin reagents.The assigned coagulation activity of different batches of the reference plasma agreed closely with experimentally obtained values. The stability of supplied batches was satisfactory as judged from the reproducibility of repeated measurements. The variability of test procedures was approximately the same on different test materials.

Sea Urchins and Circuses: The Modernist Natural Histories of Jean Painlevé and Alexander Calder

2018 ◽  
Vol 13 (2) ◽  
pp. 187-211
Author(s):  
Patricia E. Chu
Keyword(s):  
New Media ◽  
Sea Urchins ◽  
Life Sciences ◽  
Three Dimensional ◽  
Machine Age ◽  
Avant Garde ◽  
History Of ◽  
And Performance ◽  
The One ◽  
Natural Historian

The Paris avant-garde milieu from which both Cirque Calder/Calder's Circus and Painlevé’s early films emerged was a cultural intersection of art and the twentieth-century life sciences. In turning to the style of current scientific journals, the Paris surrealists can be understood as engaging the (life) sciences not simply as a provider of normative categories of materiality to be dismissed, but as a companion in apprehending the “reality” of a world beneath the surface just as real as the one visible to the naked eye. I will focus in this essay on two modernist practices in new media in the context of the history of the life sciences: Jean Painlevé’s (1902–1989) science films and Alexander Calder's (1898–1976) work in three-dimensional moving art and performance—the Circus. In analyzing Painlevé’s work, I discuss it as exemplary of a moment when life sciences and avant-garde technical methods and philosophies created each other rather than being classified as separate categories of epistemological work. In moving from Painlevé’s films to Alexander Calder's Circus, Painlevé’s cinematography remains at the forefront; I use his film of one of Calder's performances of the Circus, a collaboration the men had taken two decades to complete. Painlevé’s depiction allows us to see the elements of Calder's work that mark it as akin to Painlevé’s own interest in a modern experimental organicism as central to the so-called machine-age. Calder's work can be understood as similarly developing an avant-garde practice along the line between the bestiary of the natural historian and the bestiary of the modern life scientist.

Recommendations of The Ombudsman’s Dilemma: Between Law Enforcement Officials and Protection of Credibility

2018 ◽  
Vol 2 ◽  
pp. 1-12
Author(s):  
Dyah Adriantini Sintha Dewi
Keyword(s):  
Law Enforcement ◽  
Public Service ◽  
Public Services ◽  
Point Of View ◽  
Law Enforcement Officials ◽  
Muslim Majority ◽  
The Republic ◽  
The Government ◽  
The One ◽  
Oversight Body

The Ombudsman as an external oversight body for official performance, in Fikih Siyasah (constitutionality in Islam) is included in the supervision stipulated in legislation (al-musahabah al-qomariyah). Supervision is done so that public service delivery to the community is in accordance with the rights of the community. This is done because in carrying out its duties, officials are very likely to conduct mal administration, which is bad public services that cause harm to the community. The Ombudsman is an institution authorized to resolve the mal administration issue, in which one of its products is by issuing a recommendation. Although Law No. 37 of 2018 on the Ombudsman of the Republic of Indonesia states that the recommendation is mandatory, theombudsman's recommendations have not been implemented. This is due to differences in point of view, ie on the one hand in the context of law enforcement, but on the other hand the implementation of the recommendation is considered as a means of opening the disgrace of officials. Recommendations are the last alternative of Ombudsman's efforts to resolve the mal administration case, given that a win-win solution is the goal, then mediation becomes the main effort. This is in accordance with the condition of the Muslim majority of Indonesian nation and prioritizes deliberation in resolving dispute. Therefore, it is necessary to educate the community and officials related to the implementation of the Ombudsman's recommendations in order to provide good public services for the community, which is the obligation of the government.

Albrecht Durer and the 16TH Century Melancholy

2020 ◽  
Vol 2 ◽  
pp. 37-49
Author(s):  
Marcel Henrique Rodrigues
Keyword(s):  
Religious Culture ◽  
The Other ◽  
16Th Century ◽  
Other Hand ◽  
Close Relationship ◽  
The One ◽  
Deep Sense

Little has been discussed in academia about the close relationship between the Renaissance of the 16th century and melancholy humor, and esoteric elements arising mainly from Florentine Neoplatonism. The link between melancholy and esotericism becomes very clear when we analyze the gravure “Melencolia I” by Albrecht Dürer (1471-1528), composed of a significant number of symbols that refer to an esoteric religious culture that then emerged. Renaissance melancholy gained several nuances. On the one hand, it was considered a sin, a despicable mood characteristic of witches; on the other hand, a deep sense of inspiration typical of men of “genius”. This ambivalence also occurred in the firmament, as the melancholic people were guided by the dark planet Saturn, according to astrological belief. We also have the cultural scenario of the 16th century, especially in Dürer's Germany, which contributed to strengthening the melancholy issues.

Defending the Difference

2017 ◽  
Keyword(s):  
Social Sciences ◽  
Natural Sciences ◽  
Point Of View ◽  
True Nature ◽  
Natural Entities ◽  
The Social ◽  
The World ◽  
Methodological Difference ◽  
The Difference ◽  
The One

Dreyfus argues that there is a basic methodological difference between the natural sciences and the social sciences, a difference that derives from the different goals and practices of each. He goes on to argue that being a realist about natural entities is compatible with pluralism or, as he calls it, “plural realism.” If intelligibility is always grounded in our practices, Dreyfus points out, then there is no point of view from which one can ask about or provide an answer to the one true nature of ultimate reality. But that is consistent with believing that the natural sciences can still reveal the way the world is independent of our theories and practices.

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