scholarly journals Assessment of the population of Ostrea edulis in Sweden: A marginal population of significance?

2019 ◽  
Vol 9 (24) ◽  
pp. 13877-13888
Author(s):  
Linnea Thorngren ◽  
Per Bergström ◽  
Thomas Dunér Holthuis ◽  
Mats Lindegarth
Keyword(s):  
Ostrea Edulis ◽  
Marginal Population

scholarly journals Phylogeography in an “oyster” shell provides first insights into the genetic structure of an extinct Ostrea edulis population

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sarah Hayer ◽  
Dirk Brandis ◽  
Alexander Immel ◽  
Julian Susat ◽  
Montserrat Torres-Oliva ◽  
...  
Keyword(s):  
Large Scale ◽  
Wadden Sea ◽  
Atlantic Coast ◽  
Phylogenetic Reconstruction ◽  
Oyster Shell ◽  
Glacial Refugia ◽  
Late Nineteenth Century ◽  
Ostrea Edulis ◽  
Geographic Ranges ◽  
The North

AbstractThe historical phylogeography of Ostrea edulis was successfully depicted in its native range for the first time using ancient DNA methods on dry shells from museum collections. This research reconstructed the historical population structure of the European flat oyster across Europe in the 1870s—including the now extinct population in the Wadden Sea. In total, four haplogroups were identified with one haplogroup having a patchy distribution from the North Sea to the Atlantic coast of France. This irregular distribution could be the result of translocations. The other three haplogroups are restricted to narrow geographic ranges, which may indicate adaptation to local environmental conditions or geographical barriers to gene flow. The phylogenetic reconstruction of the four haplogroups suggests the signatures of glacial refugia and postglacial expansion. The comparison with present-day O. edulis populations revealed a temporally stable population genetic pattern over the past 150 years despite large-scale translocations. This historical phylogeographic reconstruction was able to discover an autochthonous population in the German and Danish Wadden Sea in the late nineteenth century, where O. edulis is extinct today. The genetic distinctiveness of a now-extinct population hints at a connection between the genetic background of O. edulis in the Wadden Sea and for its absence until today.

MICROECOLOGICAL FACTORS IN OYSTER EPIZOOTICS

1961 ◽  
Vol 39 (4) ◽  
pp. 449-485 ◽  
Author(s):  
Marshall Laird
Keyword(s):  
Crassostrea Virginica ◽  
Relevant Literature ◽  
Organic Pollution ◽  
Direct Effects ◽  
Ostrea Edulis ◽  
New Host ◽  
Lethal Temperatures ◽  
Canadian Data ◽  
Dead Animal ◽  
Favorable Conditions

On oyster beds as elsewhere, mud–water interfaces exhibit a biological film harboring saprobic microorganisms. The abundance of these is directly proportional to the amount of decomposing organic matter present. Different communities of protozoa and bacteria characterize each of the levels of organic pollution, which may be defined biologically in terms of a modification of the "Saprobiensystem" of Kolkwitz and Marsson. While the microorganisms concerned are not conspicuous on clean substrata except where especially favorable conditions are afforded certain of them by some dead animal or plant, their general abundance is indicative of pollution. This follows overaccumulation of reducible deposits, initiated by irregular tidal flushing, freshets, and winter icing, and rendering the microenvironment anaerobic. Ostrea edulis and Crassostrea virginica survive temporary exposure to the direct effects of such conditions as well as to near-lethal temperatures, but, weakened thereby, become vulnerable to invasion by saprobes from the enriched biological film. Unless environmental conditions improve before the oysters lose ability to recover, abnormal mortalities will be hastened by the activities of these microorganisms, notably Hexamita inflata (Protozoa). Relevant literature is reviewed, and possible local remedies are discussed. Canadian data are supported by original observations from Wales and Pakistan. Among other new host and locality records, Cristispira balbianii (Spirochaetales) and cercariae of a bucephalid trematode are listed from Ostrea belcheri from Karachi.

scholarly journals Sustainable large‐scale production of European flat oyster ( Ostrea edulis ) seed for ecological restoration and aquaculture: a review

2021 ◽  
Author(s):  
Bérenger Colsoul ◽  
Pierre Boudry ◽  
María Luz Pérez‐Parallé ◽  
Ana Bratoš Cetinić ◽  
Tristan Hugh‐Jones ◽  
...  
Keyword(s):  
Ecological Restoration ◽  
Large Scale ◽  
Scale Production ◽  
Ostrea Edulis ◽  
Large Scale Production ◽  
Flat Oyster

Flow cytometric analysis of European flat oyster, Ostrea edulis, haemocytes using a monoclonal antibody specific for granulocytes

2001 ◽  
Vol 11 (3) ◽  
pp. 269-274 ◽  
Author(s):  
Tristan Renault ◽  
Qing-Gang Xue ◽  
Stefan Chilmonczyk
Keyword(s):  
Monoclonal Antibody ◽  
Flow Cytometric Analysis ◽  
Ostrea Edulis ◽  
Flow Cytometric ◽  
Flat Oyster

Presence of the parasite Marteilia sp. in the flat oyster (Ostrea edulis L) in Greece

Aquaculture ◽  
2006 ◽  
Vol 259 (1-4) ◽  
pp. 1-5 ◽  
Author(s):  
C. Virvilis ◽  
P. Angelidis
Keyword(s):  
Ostrea Edulis ◽  
Flat Oyster

In vivo immunostimulation of the flat oyster Ostrea edulis and tissue targeting by microspheres uptake

2013 ◽  
Vol 34 (6) ◽  
pp. 1731
Author(s):  
M. Prado-Alvarez ◽  
G. Darmody ◽  
S. Lynch ◽  
A. Maloy ◽  
J. Cotterill ◽  
...  
Keyword(s):  
Ostrea Edulis ◽  
Tissue Targeting ◽  
Flat Oyster

scholarly journals Identifying the causal effect of child marriage on unmet needs for modern contraception and unintended pregnancy in Nepal: a cross-sectional study using propensity score matching

BMJ Open ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. e043532
Author(s):  
Kazutaka Sekine ◽  
Rogie Royce Carandang ◽  
Ken Ing Cherng Ong ◽  
Anand Tamang ◽  
Masamine Jimba
Keyword(s):  
Propensity Score ◽  
Propensity Score Matching ◽  
Unintended Pregnancy ◽  
Unmet Needs ◽  
Causal Effect ◽  
Secondary Data ◽  
Child Marriage ◽  
Cross Sectional ◽  
Marginal Population ◽  
Modern Contraception

ObjectivesThis study aimed to investigate whether child marriage had causal effects on unmet needs for modern contraception, and unintended pregnancy, by estimating the marginal (population-averaged) treatment effect of child marriage.DesignThis study used secondary data from the Nepal Demographic and Health Survey 2016. Applying one-to-one nearest-neighbour matching with replacement within a calliper range of ±0.01, 15–49 years old women married before the age of 18 were matched with similar women who were married at 18 or above to reduce selection bias.SettingNationally representative population survey data.ParticipantsThe sample consisted of 7833 women aged 15–49 years who were married for more than 5 years.Outcome measuresUnmet needs for modern contraception and unintended pregnancy.ResultsThe matching method achieved adequate overlap in the propensity score distributions and balance in measured covariates between treatment and control groups with the same propensity score. Propensity score matching analysis showed that the risk of unmet needs for modern contraception, and unintended pregnancy among women married as children were a 14.3 percentage point (95 % CI 10.3 to 18.2) and a 10.1 percentage point (95 % CI 3.7 to 16.4) higher, respectively, than among women married as adults. Sensitivity analysis indicated that the estimated effects were robust to unmeasured covariates.ConclusionsChild marriage appears to increase the risk of unmet needs for modern contraception and unintended pregnancy. These findings call for social development and public health programmes that promote delayed entry into marriage and childbearing to improve reproductive health and rights.

The Structure, Development, and Operation of the Hinge Ligament of Ostrea edulis

1951 ◽  
Vol s3-92 (18) ◽  
pp. 129-140
Author(s):  
E. R. TRUEMAN
Keyword(s):  
Surface Area ◽  
Outer Layer ◽  
Tensile Strain ◽  
Central Position ◽  
Ostrea Edulis ◽  
Structure Development ◽  
Dorsal Region ◽  
Larval Stages ◽  
Adult Oyster

1. The ligamental structure of Ostrea edulis is briefly described. The ligament is situated between the valves of the shell immediately below the urtibo and may be divided into two main layers, the outer and the inner, the principal features of which appear to correspond with those of other bivalves. The outer layer is divided into anterior and posterior halves by the inner layer, which occupies a central position. 2. The axis (hinge or pivotal axis) about which the valves open is situated in the adult oyster along a line drawn through the outer layer and the upper part of the inner layer. When the valves are closed the ligament above this axis is subjected to a tensile strain andthat portion below to compression, the force s so produced causing the opening of the valves. An attempt has been made t o measure this force in relation to the surface area of the valves and it is found to be approximately 4.5 gm.mm./mm.2 This figure is comparable to those obtained when certain other species of bivalves are used. 3. Th eligament is shown to develop from the simple outer layer of the early larval stages, first by the addition of aninner layer and then by growth of this structure chiefly in a ventral direction. The initial dorsal region of the ligamentsoon degenerates and at the same time the pivotal axis moves ventrally between the valves, thus increasing in length. This method of growth is compared with that of an elongate external ligament and the mechanical implications are suggested.

Επίδραση του πρωτόζωου Marteilia sp. στην ανάπτυξη του δίθυρου μαλακίου Mytilus galloprovincialis L. στο Θερμαϊκό κόλπο

2014 ◽  
Author(s):  
Δημήτριος Καραγιάννης
Keyword(s):  
Heat Shock ◽  
Heat Shock Proteins ◽  
Mytilus Galloprovincialis ◽  
Von Bertalanffy ◽  
Ostrea Edulis ◽  
Shock Proteins

Η δραματική μείωση του πληθυσμού του πλατιού στρειδιού Ostrea edulis στο Θερμαϊκό κόλπο και η διακοπή της εξαλίευσής του στα τέλη της δεκαετίας του ‘90, ανέδειξε για πρώτη φορά το πρόβλημα της μαρτελίωσης στις οστρακοκαλλιέργειες του Θερμαϊκού κόλπου. Η μαρτελίωση ανήκει στα νοσήματα υποχρεωτικής δηλώσεως της Ευρωπαϊκής Ένωσης, γεγονός που την καθιστά νόσο ιδιαίτερης σημασίας τόσο από βιολογικής όσο και οικονομικής απόψεως. Σκοπός της παρούσας διατριβής ήταν η μελέτη της επίδρασης της Marteilia sp. στην ανάπτυξη και τη φυσιολογία του καλλιεργούμενου μυδιού Mytilus galloprovincialis. Τα αποτελέσματα της παρούσας εργασίας δείχνουν ότι η Marteilia sp. έχει σημαντικά αρνητική επίδραση στην αύξηση του μυδιού M. galloprovincialis. Το μήκος, το πάχος, το ύψος και το βάρος των προσβεβλημένων μυδιών ήταν σημαντικά μικρότερο σε σχέση με τα μη προσβεβλημένα. Μάλιστα, η μείωση αυτή ήταν ανάλογη της έντασης προσβολής των μυδιών από το παράσιτο. Επιπλέον, οι συντελεστές κλίσης των αλλομετρικών σχέσεων μήκους-βάρους, ύψους-βάρους και πλάτους-βάρους ανέδειξαν σημαντικά ταχύτερη αύξηση για τα υγιή μύδια σε σύγκριση με τα προσβεβλημένα. Την αρνητική επίδραση της μαρτελίωσης στην αύξηση των προσβεβλημένων μυδιών επιβεβαίωσαν και οι εξισώσεις von Bertalanffy, σύμφωνα με τις οποίες το μέγιστο μήκος και το μέγιστο βάρος των μυδιών ήταν σημαντικά μικρότερο για τα προσβεβλημένα. Όσον αφορά το εποχικό πρότυπο προσβολής των μυδιών από τη Marteilia sp., η παρούσα έρευνα ανέδειξε την παρουσία της μαρτελίωσης καθ’ όλη τη διάρκεια του έτους, με τα ποσοστά προσβολής χαμηλά κατά τη διάρκεια του χειμώνα (3,34%) και σταδιακά να αυξάνονται φτάνοντας στα υψηλότερα (30%) κατά τους καλοκαιρινούς μήνες, όπου η θερμοκρασία του νερού ήταν στο μέγιστο. Από τη σύγκριση των δύο συστημάτων καλλιέργειας των μυδιών προέκυψε ότι τα πασσαλωτά παρουσιάζουν σημαντικά μεγαλύτερα ποσοστά προσβολής σε σχέση με τα πλωτά. Τα στελέχη της Marteilia sp. που απομονώθηκαν από το Θερμαϊκό κόλπο και ταυτοποιήθηκαν με τη μέθοδο της ένθετης PCR, όλα ανήκουν στο ίδιο στέλεχος και κατατάσσονται στον τύπο ‘O’. Μεταξύ των μεθόδων ανίχνευσης του παρασίτου (κυτταρολογικής, ιστολογικής και μοριακής) η μοριακή μέθοδος της ένθετης PCR παρουσίασε τη μεγαλύτερη ευαισθησία (88,9%), ενώ η κυτταρολογική τη μικρότερη (33,3%). Επιπλέον, σημαντικές διαφορές παρατηρήθηκαν στις τιμές του δείκτη SFG μεταξύ προσβεβλημένων και μη-προσβεβλημένων μυδιών από τη Marteilia sp. Ειδικότερα, ο δείκτης SFG ήταν σημαντικά μικρότερος στα προσβεβλημένα άτομα από ότι στα υγιή. Αναφορικά με τις φυσιολογικές παραμέτρους που προσδιορίστηκαν, οι διαφορές που διαπιστώθηκαν αποδόθηκαν στον υψηλότερο ρυθμό διήθησης και το χαμηλότερο συντελεστή απορρόφησης των προσβεβλημένων μυδιών. Αντίθετα, η κατανάλωση οξυγόνου και η απέκκριση αμμωνίας δεν επηρεάστηκαν από το βαθμό προσβολής των μυδιών. Όσον αφορά το γλυκολυτικό ρυθμιστικό ένζυμο ΡΚ, τα αποτελέσματα μετά από εγκλιματισμό στους 18°C έδειξαν μια τάση μείωσης της δραστικότητας του παρουσία της Marteilia sp. Η μείωση της δραστικότητας της ΡΚ πιθανόν να δείχνει μείωση του γλυκολυτικού ρυθμού στους αντίστοιχους ιστούς του M. galloprovincialis. Αντίθετα, στους 28°C το ένζυμο αυξάνει τη δραστικότητά του, δείχνοντας σαφή αύξηση του γλυκολυτικού ρυθμού και της παραγόμενης βιολογικής ενέργειας (ΑΤΡ), η οποία αποδίδεται στη γονιδιακή ενεργοποίηση της έκφρασης των πρωτεϊνών θερμικού πλήγματος (Hsps-heat shock proteins), προκειμένου τα κύτταρα να διατηρήσουν την πρωτεϊνική ομοιόσταση.

In the Name ofAdat: Regional Perspectives on Reform, Tradition, and Democracy in Indonesia

2008 ◽  
Vol 42 (4) ◽  
pp. 815-852 ◽  
Author(s):  
DAVID HENLEY ◽  
JAMIE S. DAVIDSON
Keyword(s):  
Indigenous Peoples ◽  
International Organizations ◽  
New Order ◽  
Political Imagination ◽  
Authoritarian Rule ◽  
Positive Role ◽  
Marginal Population ◽  
The Past ◽  
Fourth Root ◽  
Reform Tradition

AbstractThis article examines the revival ofadat(custom) in post-Suharto Indonesia, a movement which few Indonesia-watchers predicted. Four general reasons for the rise ofadatrevivalism are identified. The first is the support, both ideological and concrete, of international organizations and networks committed to the rights of indigenous peoples. The second is the uncertainty, together with the opportunities, attendant on the processes of democratization and decentralization which followed the end of Suharto's authoritarian rule. The third is the oppression of marginal population groups under the New Order. The fourth root is historical, having to do with the positive role whichadathas played in the country's political imagination since the beginning of Indonesian nationalism.Adatas a political cause involves a set of loosely related ideals which, rightly or wrongly, are associated with the past: authenticity, community, order, and justice. These ideals have been invoked in varying proportions to pursue a wide variety of political ends, including the control of resources and the exclusion of rivals as well as the protection, empowerment, and mobilization of underprivileged groups.

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