Sporopollenin Dinoflagellate Cysts

Sporopollenin Dinoflagellate Cysts PDF Author: William R. Evitt
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 360

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Sporopollenin Dinoflagellate Cysts

Sporopollenin Dinoflagellate Cysts PDF Author: William R. Evitt
Publisher:
ISBN:
Category : Medical
Languages : en
Pages : 360

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Studies on the Cell Wall of Dinoflagellate Resting Cysts

Studies on the Cell Wall of Dinoflagellate Resting Cysts PDF Author: John Peter Kokinos
Publisher:
ISBN:
Category : Biology
Languages : en
Pages : 254

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Book Description
This thesis presents a series of investigations on the specialized cell covering of a dormant stage (the resting cyst) in the life cycle of the marine dinoflagellate Lingulodinium polyedra. These cell walls, along with those of resting cysts formed by many other dinoflagellate species, are resistant to degradation and persist in the depositional environment. Selective preservation of these materials has created a rich dinoflagellate fossil record (extending back ~225 million years) which has shown great utility in biostratigraphic applications. By elucidating the nature of resting cyst walls and directly observing their development in laboratory cultures, the research presented here addresses several long-standing questions regarding both the paleontology and biology of dinoflagellates. Although resting cyst formation has been reported in other extant species, this thesis documents for the first time the morphological development of resting cysts having "fossilizable", morphologically complex cell walls. In laboratory cultures of L. polyedra, resting cyst formation is an extremely rapid phenomenon; the transition from thecate, actively swimming planozygote to spine-bearing, morphologically mature hypnozygote occurs within 10-20 minutes. The basic mechanism consists of dramatic cell expansion resulting from the widening of an interstice between the planozygotic cytoplasm and a balloon-like membrane external to the theca. Key morphological events in the development of the distinctive L. polyedra resting cyst cell covering occur within this interstice. These include early dissociation and outward migration of the theca, formation of the resistant endophragm, and growth of spines from globules on the surface of the cytoplasm. The level of morphological maturity attained by the encysting cell depends primarily on how much development occurs before rupture of the expanding outer membrane. H rupture is premature, a wide variation of resting cyst morphology may occur, particularly with respect to the size, number, and distribution of processes. The direct observation of these developmental events has shed much light on several issues regarding resting cyst morphogenesis. First, growth of L. polyedra resting cyst spines is clearly centrifugal (i.e. growing radially outward). Although not necessarily representative of spine growth in all species, this mode of formation provides a useful preliminary framework for interpreting some of the "histrichosphaerid" morphologies present in the fossil record. Second, in this species at least, the theca plays no direct role in influencing the morphology of spines. Finally, considerable variation in spine morphology is possible within one biologically-defined species. This last point has considerable significance for cyst-based taxonomy, and strongly suggests that several of the fossil morphotypes traditionally designated as separate species of Lingulodinium are, in fact, synonymous. Ultrastructural examination of L. polyedra resting cysts formed in laboratory culture has shown, for the first time, the fine structure of the cell walls enclosing a living, paleontologically-signillcant resting cyst. Unfortunately, difficulties associated with fixation and infiltration of these thick-walled structures precluded an in-depth investigation of the ultrastructural dynamics underlying the morphological development described above. Preliminary results, however, confirm earlier speculation that only the outermost wall of the L. polyedra resting cyst is normally preserved in the fossil record. This outer wall (including spines) appears constructed of closely appressed structural units, an ultrastructural style apparently widespread among species related to L. polyedra. The resistant cell walls of L. polyedra resting cysts were isolated from laboratory cultures and chemically characterized by an extensive array of analytical techniques. Both thermal (pyrolysis) and chemical (CuO oxidation) dissociation of this material yielded suites of products consistent with a macromolecular substance composed signillcantly of aromatic components. In addition, the relative abundance of carboxylated phenols among resting cyst CuO oxidation products indicated that aromatic structural units in the dinoflagellate material may be largely carbon-carbon linked, probably directly through aromatic nuclei. Such a "condensed" arrangement may be, in part, responsible for the remarkable resistance of the dinoflagellate resting cyst wall biopolymer. Overall, the aromatic signature of L. polyedra resting cyst wall material can be clearly distinguished from that of both pollen wall "sporopollenin" and classical lignin. Although some short chain carboxylic acids are generated during CuO oxidation, there is little evidence obtained by dissociation techniques to suggest the significant presence of extended polymethylenic elements in this macromolecular substance. As a result, the dinoflagellate material appears fundamentally different from the highly aliphatic "algaenans" recently identified in the cell wall of several chlorophyte species. Interestingly, pyrolysis (Py-GC/MS) of resting cyst wall material produced an abundance ofprist-1-ene, strongly suggesting the presence of bound tocopherols which may play an important structural role in the resistant cell wall biopolymer. Lipid analysis of L. polyedra culture extract revealed a series of even carbon numbered fatty acids (C14 - C24), as well as sterols (including dinosterol and cholesterol), and a full suite of tocopherols. These compounds are present during construction of the resistant outer wall of the resting cyst, and could function as precursors to the resting cyst wall biopolymer. Another possibility, given the strong aromaticity predicted by the results of pyrolysis and CuO oxidation, is some contribution by aromatic amino acids in an analogous fashion to lignin biosynthesis. The extensive chemical characterization of the outermost cell wall of L. polyedra resting cysts reported in this thesis provides the first rigorous analysis of "fossilizable" biopolymer(s) produced by an extant dinoflagellate. Furthermore, these analyses represent an unprecedented level of chemical characterization of a resistant algal cell wall biopolymer, and clearly demonstrate the unique nature of the L. polyedra resting cyst wall. As a result, this work provides the first chemical data to justify the term "dinosporin", previously proposed to distinguish the highly resistant material comprising dinoflagellate resting cyst walls from other resistant cell wall biopolymers

Biological and Geological Perspectives of Dinoflagellates

Biological and Geological Perspectives of Dinoflagellates PDF Author: F. Marret
Publisher: Geological Society of London
ISBN: 9781862393684
Category : Science
Languages : en
Pages : 386

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Book Description
This volume provides an overview of current research on fossil and modern dinoflagellates, as well as highlighting research areas for future collaboration, following the DINO9 International Conference in Liverpool. The volume is organized into four themes, with a review paper for each theme written by the key-note speaker. Each theme also includes a future research foci note following discussion during the conference. The contributions are organized into the following sections: environmental change, ecology/palaeoecology, life cycles and diversity, and stratigraphy and evolution. Also included are notes from two workshops: culture experiments and dinocysts as palaeoceanographic tracers. This volume will be of interest to both the biological and micropalaeontological communities.

Dinoflagellate Cysts and Acritarchs from the Upper Vardekløft Formation (Jurassic) of Jameson Land, East Greenland

Dinoflagellate Cysts and Acritarchs from the Upper Vardekløft Formation (Jurassic) of Jameson Land, East Greenland PDF Author: William Antony S. Sarjeant
Publisher:
ISBN:
Category :
Languages : en
Pages : 70

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Identifying Marine Diatoms and Dinoflagellates

Identifying Marine Diatoms and Dinoflagellates PDF Author: Grethe R. Hasle
Publisher: Elsevier
ISBN: 0080534414
Category : Science
Languages : en
Pages : 613

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Book Description
Identifying Marine Diatoms and Dinoflagellates is the second identification manual created from the literature developed for the Advanced International Phytoplankton Course. This version, enlarged and modified from the earlier literature, deals with the identification of marine diatoms and dinoflagellates. The data and references presented here should allow the researcher to pursue the question of valid species and how they can be verified. This volume comprises three chapters, beginning with an introductory chapter discussing the subject's historical background. The next chapter focuses on marine diatoms, providing an introduction that describes their general characteristics, life cycles, morphology and terminology, and classification. It is followed by a discussion of genera represented in marine plankton, a description of taxa, and methodology. The third and final chapter focuses on dinoflagellates, beginning with an introduction that describes their general characteristics and eukaryotic unicells. The discussion continues with terminology and morphology, identification of species, techniques for preparation of dinoflagellates for identification, common dinoflagellate synonyms, and an index of dinoflagellate taxa. This book will be of interest to practitioners in the fields of biology, zoology, and environmental protection.

Microfossils

Microfossils PDF Author: Howard Armstrong
Publisher: John Wiley & Sons
ISBN: 1118685458
Category : Science
Languages : en
Pages : 446

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Book Description
This is a new and completely rewritten edition of the well-known text Microfossils (first published in 1980) covering all the major microfossil groups, with information on taxonomy, phylogeny, ecology and palaeoecology. particular attention is given to the uses of microfossils in environmental reconstruction and biostratigraphy numerous line and half-tone illustrations emphasis on practical applications of micropalaeontology only student-friendly micropaleontology text available

Encyclopedia of Quaternary Science

Encyclopedia of Quaternary Science PDF Author: Cary Mock
Publisher: Newnes
ISBN: 0444536426
Category : Science
Languages : en
Pages : 3883

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Book Description
The second revised edition of the Encyclopedia of Quaternary Science, Four Volume Set, provides both students and professionals with an up-to-date reference work on this important and highly varied area of research. There are lots of new articles, and many of the articles that appeared in the first edition have been updated to reflect advances in knowledge since 2006, when the original articles were written. The second edition will contain about 375 articles, written by leading experts around the world. This major reference work is richly illustrated with more than 3,000 illustrations, most of them in colour. Research in the Quaternary sciences has advanced greatly in the last 10 years, especially since topics like global climate change, geologic hazards and soil erosion were put high on the political agenda. This second edition builds upon its award-winning predecessor to provide the reader assured quality along with essential updated coverage Contains 357 broad-ranging articles (4310 pages) written at a level that allows undergraduate students to understand the material, while providing active researchers with a ready reference resource for information in the field. Facilitates teaching and learning The first edition was regarded by many as the most significant single overview of Quaternary science ever, yet Editor-in-Chief, Scott Elias, has managed to surpass that in this second edition by securing even more expert reviews whilst retaining his renowned editorial consistency that enables readers to navigates seamlessly from one unfamiliar topic to the next

Introduction to Marine Micropaleontology

Introduction to Marine Micropaleontology PDF Author: B.U. Haq
Publisher: Elsevier
ISBN: 0080534961
Category : Science
Languages : en
Pages : 385

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Book Description
This beautifully illustrated text book, with state-of-the-art illustrations, is useful not only for an introduction to the subject, but also for the application of marine microfossils in paleoceanographic, paleoenvironmental and biostratigraphic analyses. The recent revival of interest in marine micropaleontology worldwide in the wake of the development of sequence stratigraphic models has led to the decision to reissue the volume in its original, but paperback, form. The ideas expressed in various chapters of this second edition remain as valid today as they were when the book was first issued. The text, however, includes an updated Phanerozoic geologic time which has been considerably modified since the 1980s.

Dinoflagellate Cysts from Marine Jurassic Deposits of Denmark and Poland

Dinoflagellate Cysts from Marine Jurassic Deposits of Denmark and Poland PDF Author: Niels Erik Poulsen
Publisher:
ISBN:
Category : Dinoflagellate cysts
Languages : en
Pages : 250

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Stratigraphy & Timescales

Stratigraphy & Timescales PDF Author:
Publisher: Academic Press
ISBN: 0128115505
Category : Science
Languages : en
Pages : 520

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Book Description
Stratigraphy and Timescales covers current research across a wide range of stratigraphic disciplines, providing information on recent developments for the geoscientific research community. This fully commissioned review publication aims to foster and convey progress in stratigraphy, including geochronology, magnetostratigraphy, lithostratigraphy, event-stratigraphy, isotope stratigraphy, astrochronology, climatostratigraphy, seismic stratigraphy, biostratigraphy, ice core chronology, cyclostratigraphy, palaeoceanography, sequence stratigraphy, and more. - Contains contributions from leading authorities in the field - Informs and updates on all the latest developments in the field - Aims to foster and convey progress in stratigraphy, including geochronology, magnetostratigraphy, lithostratigraphy, event-stratigraphy, and more