RHYTHMIC SEXUAL MATURITY AND SPAWNING OF CERTAIN BIVALVE MOLLUSKS

1932 ◽  
Vol 7 (1) ◽  
pp. 255-276 ◽  
Author(s):  
HELEN I. BATTLE
Keyword(s):  
Mytilus Edulis ◽  
Germ Cells ◽  
Deep Water ◽  
Tidal Cycle ◽  
Sexual Maturity ◽  
Mya Arenaria ◽  
Bivalve Mollusks ◽  
The Sun ◽  
Passamaquoddy Bay ◽  
New Moon

From the middle of June to the middle of September the germ cells of Mytilus edulis L. and Macoma baltica L. in Passamaquoddy bay mature during the new-moon spring tides and are spawned throughout the remainder of the lunar tidal cycle. The initiation of spawning may be due to increased temperature since the low water of the neaps occurs about midday when the mud flats are heated by the rays of the sun. Mya arenaria L. shows the same phenomenon to a lesser degree from mid-June through August. Yoldia sapotilla (Gould), a deep-water form, has a bimonthly spawning on the spring tides.

Trial Control of the Greater Clam Drill (Lunatia heros) by Manual Collection

1958 ◽  
Vol 15 (6) ◽  
pp. 1355-1369 ◽  
Author(s):  
J. C. Medcof ◽  
L. W. Thurber
Keyword(s):  
Mytilus Edulis ◽  
Mya Arenaria

Soft-shelled clams (Mya arenaria) 38 mm. long were planted 172 per m.2 in three 10 m.2 plots in a sandy flat where none occurred naturally but where there were 6 drills per m.2 feeding on mussels (Mytilus edulis). After plantings, at least 300 drills entered each plot daily. After 12 days clam survival was only 19% in the plot where there was no protection; 31% where soil was raked before planting and exposed drills removed (84% efficient); 34% where this pre-planting clearance was combined with 8 post-planting, low-tide, manual collections of surfacing drills (3% to 5% efficient). These intense efforts had little effect and would be unjustified on public beds even if much more effective. Drills kill more than half their prey without boring their shells. A higher proportion of the drill population comes to the surface by night (6%) than by day (3%) and small drills are unexplainably scarce.

scholarly journals Astronomy at the service of the Islamic society

2009 ◽  
Vol 5 (S260) ◽  
pp. 514-521
Author(s):  
Ilias M. Fernini
Keyword(s):  
Proper Time ◽  
Astronomical Observatory ◽  
The Sun ◽  
The Moon ◽  
Scientific Institutions ◽  
Mathematical Astronomy ◽  
Islamic Empire ◽  
New Moon ◽  
Islamic Society

AbstractThe Islamic society has great ties to astronomy. Its main religious customs (start of the Islamic month, direction of prayer, and the five daily prayers) are all related to two main celestial objects: the Sun and the Moon. First, the start of any Islamic month is related to the actual seeing of the young crescent after the new Moon. Second, the direction of prayer, i.e., praying towards Mecca, is related to the determination of the zenith point in Mecca. Third, the proper time for the five daily prayers is related to the motion of the Sun. Everyone in the society is directly concerned by these customs. This is to say that the major impetus for the growth of Islamic astronomy came from these three main religious observances which presented an assortment of problems in mathematical astronomy. To observe these three customs, a new set of astronomical observations were needed and this helped the development of the Islamic observatory. There is a claim that it was first in Islam that the astronomical observatory came into real existence. The Islamic observatory was a product of needs and values interwoven into the Islamic society and culture. It is also considered as a true representative and an integral par of the Islamic civilisation. Since astronomy interested not only men of science, but also the rulers of the Islamic empire, several observatories have flourished. The observatories of Baghdad, Cairo, Córdoba, Toledo, Maragha, Samarqand and Istanbul acquired a worldwide reputation throughout the centuries. This paper will discuss the two most important observatories (Maragha and Samarqand) in terms of their instruments and discoveries that contributed to the establishment of these scientific institutions.

Évaluation écotoxicologique de la baie des Anglais à Baie-Comeau (Québec)

1993 ◽  
Vol 28 (4) ◽  
pp. 665-686 ◽  
Author(s):  
Jocelyne Pellerin-Massicotte ◽  
Bruno Vincent ◽  
Émilien Pelletier
Keyword(s):  
Mytilus Edulis ◽  
Mya Arenaria

Résumé La baie des Anglais à Baie-Comeau (Québec) est un site industriel reconnu comme étant contaminé aux hydrocarbures et aux biphényls polychlorés (BPC). Une expérience de transfert à moyen terme de deux bivalves marins, Mya arenaria et Mytilus edulis L., a été réalisée entre un site de référence en aval de la baie des Anglais (Franquelin) et des sites contaminés près de Baie-Comeau suivant un gradient de contamination déterminé selon des données physico-chimiques antérieures. Les analyses chimiques de contaminants ont montré qu’il n’y a pas eu d’enrichissement en hydrocarbures, au mercure et en BPC pour toute la durée du protocole mais, parmi les sondes bioanalytiques choisies pour évaluer l’état de santé de cet écosystème, celles qui se sont avérées les plus sensibles chez Mya arenaria furent le glycogène et les lipides dans les gonades, et pour les deux bivalves, la fragilité de la membrane lysosomale de la glande digestive qui est un excellent indicateur de stress toxique. Les présents résultats sont compatibles avec un modèle qui consisterait à établir une évaluation ecotoxicologique d’un écosystème que l’on soupçonne perturbé par la pollution par (i) l’analyse de la bioaccumulation des substances toxiques que l’on croit présentes dans l’écosystème (hydrocarbures, BPC et métaux lourds) et (ii) l’évaluation des effets physiologiques et biochimiques des polluants à l’aide de sondes bioanalytiques appropriées.

The Effect of Synchronous Moulting on Body Copper and Zinc Concentrations in Four Species of Talitrid Amphipods (Crustacea)

1991 ◽  
Vol 71 (2) ◽  
pp. 481-488 ◽  
Author(s):  
J. M. Weeks ◽  
P. G. Moore
Keyword(s):  
Tidal Cycle ◽  
Zinc Content ◽  
Lunar Cycle ◽  
Moult Cycle ◽  
Metal Concentrations ◽  
Total Copper ◽  
Copper And Zinc ◽  
Talitrus Saltator ◽  
Zinc Concentrations ◽  
New Moon

Analysis of the total copper and zinc content of four species of talitrid amphipods, Orchestia gammarellus, O. mediterranea, Talitrus saltator and Talorchestia deshayesii throughout a complete spring/neap tidal cycle failed to reveal any significant effects of moulting upon body copper or zinc in any species. Moulting was synchronized to the lunar cycle only in T. saltator, taking place 5–7 days prior to a new moon. The fact that no significant changes in body metal concentrations took place with the moult cycle is discussed in relation to the use of talitrid amphipods in copper and zinc biomonitoring programmes.

A Graphical Approach to Some Problems in Maya Astronomy

1946 ◽  
Vol 12 (1) ◽  
pp. 35-46 ◽  
Author(s):  
Robert H. Merrill
Keyword(s):  
Graphical Methods ◽  
The Sun ◽  
The Moon ◽  
Graphical Approach ◽  
New Moon ◽  
Dresden Codex

Although graphical methods are in common use by engineers and astronomers, they are less familiar to archaeologists. To portray the rhythm of celestial motions, astronomers often use “elongation” diagrams to show angular distances of moon and planets from the sun on each day of the calendar year.The Maya recognized a zone within which the planets could not be seen because of proximity to the brilliant disk of the sun. The moon cannot be seen on the day of conjunction with the sun, and is generally invisible on the day before and the day after this “new moon day.” The three consecutive days in the lunar table of the Dresden Codex may represent the 3-day phase of moon disappearance.

Decapitated Lunar Goddesses in Aztec Art, Myth, and Ritual

1997 ◽  
Vol 8 (2) ◽  
pp. 185-206 ◽  
Author(s):  
Susan Milbrath
Keyword(s):  
Solar Eclipse ◽  
Seasonal Cycle ◽  
Full Moon ◽  
The Sun ◽  
The Moon ◽  
Seasonal Transition ◽  
The Earth ◽  
New Moon ◽  
The Demonic

AbstractAztec images of decapitated goddesses link the symbolism of astronomy with politics and the seasonal cycle. Rituals reenacting decapitation may refer to lunar events in the context of a solar calendar, providing evidence of a luni-solar calendar. Decapitation imagery also involves metaphors expressing the rivalry between the cults of the sun and the moon. Huitzilopochtli's decapitation of Coyolxauhqui can be interpreted as a symbol of political conquest linked to the triumph of the sun over the moon. Analysis of Coyolxauhqui's imagery and mythology indicates that she represents the full moon eclipsed by the sun. Details of the decapitation myth indicate specific links with seasonal transition and events taking place at dawn and at midnight. Other decapitated goddesses, often referred to as earth goddesses with “lunar connections,” belong to a complex of lunar deities representing the moon within the earth (the new moon). Cihuacoatl, a goddess of the new moon, takes on threatening quality when she assumes the form of a tzitzimime attacking the sun during a solar eclipse. The demonic new moon was greatly feared, for it could cause an eternal solar eclipse bringing the Aztec world to an end.

scholarly journals Extracellular Vesicles and Post-Translational Protein Deimination Signatures in Mollusca—The Blue Mussel (Mytilus edulis), Soft Shell Clam (Mya arenaria), Eastern Oyster (Crassostrea virginica) and Atlantic Jacknife Clam (Ensis leei)

Biology ◽  
2020 ◽  
Vol 9 (12) ◽  
pp. 416
Author(s):  
Timothy J. Bowden ◽  
Igor Kraev ◽  
Sigrun Lange
Keyword(s):  
Mytilus Edulis ◽  
Crassostrea Virginica ◽  
Blue Mussel ◽  
Binding Protein ◽  
Pdz Domain ◽  
Eastern Oyster ◽  
Mya Arenaria ◽  
Beta Catenin ◽  
Soft Shell Clam ◽  
Soft Shell

Oysters and clams are important for food security and of commercial value worldwide. They are affected by anthropogenic changes and opportunistic pathogens and can be indicators of changes in ocean environments. Therefore, studies into biomarker discovery are of considerable value. This study aimed at assessing extracellular vesicle (EV) signatures and post-translational protein deimination profiles of hemolymph from four commercially valuable Mollusca species, the blue mussel (Mytilus edulis), soft shell clam (Mya arenaria), Eastern oyster (Crassostrea virginica), and Atlantic jacknife clam (Ensis leei). EVs form part of cellular communication by transporting protein and genetic cargo and play roles in immunity and host–pathogen interactions. Protein deimination is a post-translational modification caused by peptidylarginine deiminases (PADs), and can facilitate protein moonlighting in health and disease. The current study identified hemolymph-EV profiles in the four Mollusca species, revealing some species differences. Deiminated protein candidates differed in hemolymph between the species, with some common targets between all four species (e.g., histone H3 and H4, actin, and GAPDH), while other hits were species-specific; in blue mussel these included heavy metal binding protein, heat shock proteins 60 and 90, 2-phospho-D-glycerate hydrolyase, GTP cyclohydrolase feedback regulatory protein, sodium/potassium-transporting ATPase, and fibrinogen domain containing protein. In soft shell clam specific deimination hits included dynein, MCM3-associated protein, and SCRN. In Eastern oyster specific deimination hits included muscle LIM protein, beta-1,3-glucan-binding protein, myosin heavy chain, thaumatin-like protein, vWFA domain-containing protein, BTB domain-containing protein, amylase, and beta-catenin. Deiminated proteins specific to Atlantic jackknife clam included nacre c1q domain-containing protein and PDZ domain-containing protein In addition, some proteins were common as deiminated targets between two or three of the Bivalvia species under study (e.g., EP protein, C1q domain containing protein, histone H2B, tubulin, elongation factor 1-alpha, dominin, extracellular superoxide dismutase). Protein interaction network analysis for the deiminated protein hits revealed major pathways relevant for immunity and metabolism, providing novel insights into post-translational regulation via deimination. The study contributes to EV characterization in diverse taxa and understanding of roles for PAD-mediated regulation of immune and metabolic pathways throughout phylogeny.

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