scholarly journals The Earliest Japanese records of the invasive European ascidian Ascidiella aspersa (Müller, 1776) (Urochordata: Ascidiidae) from Mutsu and Ago Bays, with a brief discussion of its invasion processes

2019 ◽  
Vol 36 (1) ◽  
pp. 1-6 ◽  
Author(s):  
Teruaki Nishikawa ◽  
Akira Yasuda ◽  
Yusuke Murata ◽  
Michio Otani
Keyword(s):  
Ascidiella Aspersa

Nitrogen Excretion in Ascidiacea II. Storage Excretion and the Uricolytic Enzyme System

1965 ◽  
Vol 42 (2) ◽  
pp. 299-305
Author(s):  
IVAN GOODBODY
Keyword(s):  
Uric Acid ◽  
Calcium Carbonate ◽  
Protein Metabolism ◽  
Enzyme System ◽  
Purine Metabolism ◽  
Nitrogen Excretion ◽  
Purine Base ◽  
Purine Bases ◽  
Ascidiella Aspersa

1. The evidence for the occurrence of storage excretion in ascidians is reviewed. Most species probably store uric acid or purine bases in some form. 2. The renal concretions of Ascidia nigra and Phallusia mammillata contain 50-60% uric acid, the remainder of the concretion is unidentified but is non-nitrogenous and is not calcium carbonate. In Ascidiella aspersa the concretion is predominantly composed of calcium carbonate and there is no significant quantity of uric acid or purine base. 3. Uric acid is also identified in Molgula manhattensis, Polycarpa obtecta, Pyura vittata and Herdmania momus. 4. Storage excretion probably results from a deficiency in the uricolytic enzyme system. It is concluded that while protein metabolism is ammonotelic, purine metabolism is uricotelic or xanthotelic.

Effects of Temperature and Salinity on Egg Development of Ascidiella aspersa (Ascidiacea, Phlebobranchia, Ascidiidae)

2018 ◽  
Vol 36 (2) ◽  
pp. 232-240
Author(s):  
Donghyun Kim ◽  
Min Kyung Kim ◽  
Juun Park ◽  
Dong Gun Kim ◽  
Tae Joong Yoon ◽  
...  
Keyword(s):  
Egg Development ◽  
Effects Of Temperature ◽  
Ascidiella Aspersa

Association of the Mytilid Musculus viator with the Invasive Tunicate Ascidiella aspersa in San Matías Gulf, Argentine Patagonia

2018 ◽  
Vol 36 (2) ◽  
pp. 286
Author(s):  
Carolina Lazari ◽  
María del Socorro Doldan ◽  
Angélica Carignano ◽  
María Eugenia Orrego ◽  
Enrique M. Morsan
Keyword(s):  
Argentine Patagonia ◽  
Ascidiella Aspersa

The biology and functional morphology of Modiolarca subpicta (Bivalvia: Mytilidae: Musculinae), epizoically symbiotic with Ascidiella aspersa (Urochordata: Ascidiacea), from the Kattegat, northern Jutland, Denmark

2010 ◽  
Vol 91 (8) ◽  
pp. 1637-1649 ◽  
Author(s):  
Brian Morton ◽  
Grete E. Dinesen
Keyword(s):  
Functional Morphology ◽  
Reproductive Cycle ◽  
Intimate Relationship ◽  
Dorsal Side ◽  
Stability Characteristic ◽  
Rocky Shores ◽  
Free Living ◽  
North Eastern ◽  
Ascidiella Aspersa

This study of the little known north-eastern Atlantic mytilid Modiolarca subpicta suggests a more intimate relationship with ascidians and, especially, Ascidiella aspersa, than has hitherto been appreciated. Both live for ~18 months and the reproductive cycle of both is approximately co-ordinated so that juvenile ascidians become available as hosts to the settling spat of the symbiotically epizoic M. subpicta each summer. Settling spat of M. subpicta are thought to be attracted to the exhalant flow from the ascidian's anal siphon. After the ascidian's death, the liberated mussels may adopt a wandering, free-living, lifestyle they have occasionally been reported to pursue. Anatomically, M. subpicta is of the typical mytilid plan, albeit simplified commensurate upon its normal lifestyle of protective envelopment within the host's tunic. The foot, however, is highly mobile and in addition to being used for locomotion, especially in juveniles, is responsible for the planting of byssal threads, typically dorsally above the shell, so that each individual stimulates the ascidian to produce an epidermal pocket into which it manœuvres itself and reposes, securely attached, but dorsal side down Modiolarca subpicta, epizoic in the tests of ascidians, could have evolved from a more isomyarian, equivalve, ancestor via a nestling, epibyssate, Trichomusculus-like shaped intermediary with ventral flattening and, hence, stability characteristic of the more familiar heteromyarian mytilids of rocky shores and lotic freshwaters being achieved through living dorsal side down.

Vascular and Pericardiac Pressures in Ascidiella Aspersa (Urochordata: Ascidiacea)

1985 ◽  
Vol 65 (4) ◽  
pp. 911-922 ◽  
Author(s):  
H. D. Jones
Keyword(s):  
Blood Flow ◽  
Ascidiella Aspersa

INTRODUCTIONThe heart of tunicates is of physiological interest for several reasons: it is a simple peristaltic tube; it lacks valves; and the direction of the contractions changes periodically thus reversing the direction of blood flow. The phylogenetic importance of tunicates, being invertebrate chordates, also make physiological details of interest.

The Mechanics of the Blood Vascular Sustem of Ascidiella Aspersa

1950 ◽  
Vol 27 (1) ◽  
pp. 14-28
Author(s):  
C. A. HAYWOOD ◽  
H. P. MOON
Keyword(s):  
Back Pressure ◽  
The Other ◽  
Evidence Based ◽  
Quantitative Evidence ◽  
Ascidiella Aspersa

1. The reversal of the tunicate heart involves two problems: first, why it stops beating in a particular direction; and secondly, why having stopped it should then reverse. 2. Two types of theory have been put forward, one based on the idea that a ‘back pressure’ is gradually built up which compels the heart to stop, and the other depending on opposing centres of contraction at each end of the heart taking control alternately. 3. The present paper provides quantitative evidence, based on Ascidiella aspersa (O. F. Mueller), that a back pressure is built up. The faster the heart beats the more frequently reversals occur, a back pressure building up more rapidly when the heart beats quickly. 4. Various criticisms of the back-pressure theory are considered and discussed. 5. Examples are given of other closed contractile systems containing fluid which show reversal, the tunicate heart being by no means unique.

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