Duration and Timing of Spermatogenesis in a Stock of the Mussel Mytilus Californianus

1982 ◽  
Vol 62 (3) ◽  
pp. 509-519 ◽  
Author(s):  
R. Norman Kelley ◽  
Michael J. Smith-Ashwood ◽  
Derek V. Ellis
Keyword(s):  
Mytilus Edulis ◽  
Dose Response ◽  
Marine Invertebrates ◽  
Mytilus Californianus ◽  
Pilot Test ◽  
Reproductive Timing ◽  
Gonadal Tissue ◽  
Response Measures ◽  
Γ Ray ◽  
Key Questions

Determining the duration and timing of spermatogenesis in Mytilus californianus Conrad became key questions in our study of carcinogen-mutagen indices in the marine environment. We had postulated that the murine sperm deformation assay of Bruce, Furrer & Wyrobek (1974) should have marine analogues, and we assayed a number of marine invertebrates sampled near potentially carcinogenic waste flows, and by γ-ray dose-response experiments. Our field results demonstrated some deformation but only at a very low level (less than 5 % in Mytilus edulis L.). Development of a γ-ray doseresponse (90–900 rads) procedure for M. californianus by radium needle inserted through a drilled hole closed with a plastic plug, and subsequent biopsy of gonadal tissue at measured distances from the site of irradiation, did not show deformations from a pilot test in June 1979. If a viable dose-response procedure was to be developed it was necessary to establish seasonal reproductive timing so that specimens could be collected or cultured to maximize spermatogenesis and hence response potential, and also to establish the duration of spermatogenesis so that response measures via a gonadal tissue extraction could be appropriately timed.

Abrupt mortality of marine invertebrates at the Younger Dryas-Holocene transition in a shallow inlet of the Goldthwait Sea

The Holocene ◽  
2018 ◽  
Vol 28 (12) ◽  
pp. 1894-1908
Author(s):  
Andréanne Bourgeois-Roy ◽  
Hugo Crites ◽  
Pascal Bernatchez ◽  
Denis Lacelle ◽  
André Martel
Keyword(s):  
Mytilus Edulis ◽  
Marine Invertebrates ◽  
Transition Period ◽  
Marine Invertebrate ◽  
Laurentide Ice Sheet ◽  
The North ◽  
Invertebrate Diversity ◽  
Shell Deposit ◽  
The Impact ◽  
Rapid Environmental Change

The late Pleistocene–early Holocene transition period was characterized by rapid environmental change. Here, we investigate the impact of these changes on the marine invertebrates living in a shallow inlet of the post-glacial Goldthwait Sea. The site is located near Baie-Comeau (QC, Canada), where a number of remarkably well-preserved shell deposits are found along the Rivière aux Anglais Valley on the north shore of the St. Lawrence maritime estuary. Seven phyla of marine invertebrates with a minimum of 25 species or taxa were inventoried in a shell deposit, dominated by a community of Hiatella arctica with Mytilus edulis and barnacles composing the subcommunity. The majority of taxa identified in the shell deposit are boreal and sub-Arctic species; however, temperate species that exist today in the St. Lawrence maritime estuary have not been found. Based on marine invertebrate diversity and δ18O(CaCO3) of Mytilus edulis, the water in the shallow inlet of the Goldthwait Sea must have been cold and saline. The range of AMS 14C ages from 15 Mytilus edulis, constrained to 10,900 and 10,690 cal. yr BP, and exceptional state of preservation of adult and juvenile molluscan specimens suggest the abrupt mortality of entire invertebrate communities due to changing hydrodynamic conditions that included the combined effect of freshwater discharge from the receding Laurentide Ice Sheet and rapid isostatic uplift.

MUTAGENESIS IN CAENORHABDITIS ELEGANS. II. A SPECTRUM OF MUTATIONAL EVENTS INDUCED WITH 1500 R OF γ-RADIATION

Genetics ◽  
1985 ◽  
Vol 109 (3) ◽  
pp. 493-511
Author(s):  
Raja E Rosenbluth ◽  
Cheryl Cuddeford ◽  
David L Baillie
Keyword(s):  
Dose Response ◽  
Response Curve ◽  
Chromosomal Rearrangements ◽  
Γ Radiation ◽  
Recessive Lethal ◽  
C Elegans ◽  
Chromosome Breaks ◽  
Additional Chromosome ◽  
Γ Ray ◽  
Do So

ABSTRACT We previously established a γ-ray dose-response curve for recessive lethal events (lethals) captured over the eT1 balancer. In this paper we analyze the nature of lethal events produced, with a frequency of 0.04 per eT1 region, at a dose of 1500 r. To do so, we developed a protocol that, in the absence of cytogenetics, allows balanced lethals to be analyzed for associated chromosomal rearrangements. A set of 35 lethal strains was chosen for the analysis. Although the dosage was relatively low, a large number of multiple-break events were observed. The fraction of lethals associated with rearrangements was found to be 0.76. Currently most X- and γ-ray dosages used for mutagenesis in C. elegans are 6000-8000 r. From our data we conservatively estimated that 43% of rearrangements induced with 8000 r would be accompanied by additional chromosome breaks in the genome. With 1500 r the value was 5%.—The 35 lethals studied were derived from 875 screened F1's. Among these lethals there were (1) at least two unc-36 duplications, (2) at least four translocations, (3) at least six deficiencies of chromosome V (these delete about 90% of the unc-60 to unc-42 region) and (4) several unanalyzed rearrangements. Thus, it is possible to recover desired rearrangements at reasonable rates with a dose of only 1500 r.—We suggest that the levels of ionizing radiation employed in most published C. elegans studies are excessive and efforts should be made to use reduced levels in the future.

Sodium absorption coupled to ammonia excretion in osmoconforming marine invertebrates

1986 ◽  
Vol 251 (5) ◽  
pp. R957-R962 ◽  
Author(s):  
K. C. Hunter ◽  
L. B. Kirschner
Keyword(s):  
Cation Exchange ◽  
Marine Invertebrates ◽  
Ammonia Excretion ◽  
Mytilus Californianus ◽  
Sodium Absorption ◽  
Proton Efflux ◽  
Petrolisthes Cinctipes ◽  
Na Uptake

Evidence was sought for the presence of amiloride-sensitive Na-NH4 and NaH exchange systems in four species of marine osmoconformers. When the crabs Cancer antennarius and Petrolisthes cinctipes were in seawater (SW), amiloride (10(-4) M) reduced NH3 efflux by approximately 33 and 60%. Inhibition was reversible on removing the amiloride. In dilute (60%) SW, inhibition of NH3 output by C. antennarius was even greater than in SW. Na+ uptake by P. cinctipes was reduced by approximately 20% in the presence of amiloride (the measurement was not made on C. antennarius). Amiloride had no effect on proton efflux in either crab. The data suggest that Na-NH4 exchange occurs in these animals but that Na-H exchange does not occur. The inhibitor had no effect on NH+4 excretion by the polychaete worm Nephtys caecoides and the mussel Mytilus californianus; it was also without effect on proton output by the worm. The data suggest that the exchange systems are absent from these animals. Implications of these observations for the evolution of such cation exchange systems are discussed.

Fecundity and Reproductive Effort in the Blue Mussel (Mytilus edulis), the Sea Urchin (Strongylocentrotus droebachiensis), and the Snow Crab (Chionoecetes opilio) from Populations in Nova Scotia and Newfoundland

1979 ◽  
Vol 36 (8) ◽  
pp. 955-964 ◽  
Author(s):  
R. J. Thompson
Keyword(s):  
Mytilus Edulis ◽  
Sea Urchin ◽  
Reproductive Effort ◽  
Marine Invertebrates ◽  
Blue Mussel ◽  
Strongylocentrotus Droebachiensis ◽  
Snow Crab ◽  
Recent Theory ◽  
Chionoecetes Opilio ◽  
Reproductive Phases

Fecundity varies from year to year in blue mussels (Mytilus edulis) from Petpeswick Inlet, N.S., and from Bellevue, Nfld. This observation is consistent with recent theory that suggests that reproductive effort (that proportion of the energy budget allocated to reproduction) should be variable in animals such as marine bivalves that are unable to "predict" the quality of the environment for their juveniles. Estimates of fecundity in the sea urchin (Strongylocentrotus droebachiensis) and the snow crab (Chionoecetes opilio) are also presented. Reproductive effort increases with advancing age in the three species of invertebrates studied, although in the mussel the transition from growth to reproduction is more gradual than it is in the sea urchin or the female snow crab, which exhibit early growth and delayed reproduction. The degree to which the growth and reproductive phases are separated in each species may be determined in part by the predictability of the food supply. The allocation of resources primarily to growth rather than to reproduction in young (small) individuals may be seen as a response to selective pressure resulting from higher mortality and from competition. Key words: growth, production, reproductive strategy, energy partitioning, marine invertebrates, gametes

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