Function of the Neural Sheath in Marine and Freshwater Molluscs. Evidence for Restriction of Sodium Loss in Freshwater Species

1972 ◽  
Vol 56 (2) ◽  
pp. 433-439
Author(s):  
BETTY M. TWAROG ◽  
T. HIDAKA
Keyword(s):  
Action Potentials ◽  
Marine Bivalve ◽  
Common Denominator ◽  
Freshwater Species ◽  
Freshwater Bivalve ◽  
Elliptio Complanata ◽  
Freshwater Molluscs ◽  
Freshwater Clams ◽  
Sodium Loss ◽  
Neural Sheath

1. Action potentials were observed in cerebrovisceral connectives of a marine bivalve, Mytilus edulis L., and two species of freshwater bivalve, Anodonta cataracta and Elliptio complanata. 2. In Mytilus nerve, responses to stimulation in both the intact and the de-sheathed nerve were blocked after two minutes in a sodium-free saline. Restoration of normal sodium levels reversed the block within 5 min. 3. In nerves of the freshwater species, Anodonta and Elliptio, the action potential of the sheathed nerve altered very slightly after one hour of stimulation in a sodium-free solution. The completely de-sheathed nerve, however, was blocked within one minute in sodium-free saline. The block was rapidly reversible. 4. It is concluded, contrary to conclusions of previous investigators, that the neural sheath in freshwater clams is just as vital to restriction of sodium loss as it is in amphibia and insects, and it would seem logical to seek out a common denominator of sheath function. Several possible mechanisms are put forth and discussed.

scholarly journals Evaluation of a nonlethal technique for hemolymph collection in Elliptio complanata, a freshwater bivalve (Mollusca: Unionidae)

2005 ◽  
Vol 65 ◽  
pp. 159-165 ◽  
Author(s):  
LL Gustafson ◽  
MK Stoskopf ◽  
AE Bogan ◽  
W Showers ◽  
TJ Kwak ◽  
...  
Keyword(s):  
Freshwater Bivalve ◽  
Elliptio Complanata

A new freshwater species of the genus Dolops (Crustacea : Branchiura) parasitic on a galaxiid fish of Tasmania - with comments on disjunct distribution patterns in the southern hemisphere

1969 ◽  
Vol 17 (1) ◽  
pp. 49 ◽  
Author(s):  
G Fryer
Keyword(s):  
New Species ◽  
Southern Hemisphere ◽  
Continental Drift ◽  
Distribution Patterns ◽  
Disjunct Distribution ◽  
Freshwater Species ◽  
Bivalve Molluscs ◽  
Freshwater Bivalve ◽  
A New Species

A new species of Dolops is described from Lake Surprise, Tasmania, where it has been found on a galaxiid fish. Hitherto the genus has been known only from freshwater in S. America and Africa. Taxonomic errors involving an alleged Asiatic member of the genus are rectified and recent gross mistreatment of the classification of the Branchiura is discussed. The genus Dolops is re-defined. Evidence bearing on the history and dispersal of Dolops and other organisms is reviewed, particular attention being directed to the freshwater bivalve molluscs formerly assigned to the Mutelidae. While the African and S. American muteloids belong to closely related families of the Muteloidea, the Australasian forms formerly thought of as representatives of this group have no place in this superfamily. They, and certain S. American bivalves, however, show unambiguous trans-Antarctic affinities as they belong to a common family, the Hyriidae. Taking into account recent work, both geological and biological, and in spite of powerful voices raised in objection, the disjunct distribution of several groups of animals in the Southern Hemisphere seems to be most plausibly explained as a result of continental drift, though no dogmatic claims are made.

The effects of source and destination on growth and metal uptake in freshwater clams reciprocally transplanted among south central Ontario lakes

1989 ◽  
Vol 67 (4) ◽  
pp. 855-863 ◽  
Author(s):  
Scott G. Hinch ◽  
Roger H. Green
Keyword(s):  
Metal Uptake ◽  
Soft Tissues ◽  
Common Source ◽  
Transplant Experiment ◽  
Reciprocal Transplant Experiment ◽  
Post Transplant ◽  
Elliptio Complanata ◽  
South Central ◽  
Freshwater Clams ◽  
Strong Source

The relative contributions of genotype and environment to growth and metal uptake in freshwater unionid clams (Elliptio complanata) were evaluated using a reciprocal transplant experiment. In August 1985, comparable sites were selected in three south central Ontario lakes with alkalinities of 22, 153, and 238 μequiv.∙L−1. Shell length, height, and width varied in a manner that could not be related to lake alkalinities. There were differences among the clam populations in allelic frequencies (at the Pgm and Lap-2 loci). Clams were marked, measured, and reciprocally transplanted among the three lakes. In August 1986, marked individuals were recovered, remeasured, and analysed for levels of Cu, Zn, Mn, and Cd in soft tissues. The transplant source had a strong influence on clam growth during the post-transplant year. This source effect may result from genetic differences among the populations. Tissue metal concentrations at the end of the post-transplant year were a function of both source and destination. The use of freshwater clams as transplant biomonitors must be reassessed since there is a strong source component to growth and metal uptake. In transplant experiments a common source (a particular site within a particular lake) should be used, and post-transplant periods of more than 1 year may be necessary for the influence of the destination environment to dominate the influence of the source environment.

Energy distribution in biomass estimates within a freshwater bivalve community

1982 ◽  
Vol 60 (11) ◽  
pp. 2753-2756 ◽  
Author(s):  
C. G. Paterson
Keyword(s):  
Energy Distribution ◽  
New Brunswick ◽  
Standing Stock ◽  
Freshwater Bivalve ◽  
Elliptio Complanata ◽  
Stock Biomass ◽  
Shell Fragments

In an association of the bivalves Elliptio complanata, Anodonta cataracta, and Lampsilis ochracea in a New Brunswick lake, the distribution of standing stock biomass is among tissue (64.6%), shells of living individuals (19.4%), and empty shells and shell fragments (16.0%). Failure to consider the latter two energy compartments would result in serious underestimates of standing stock biomass.

scholarly journals Výsledky průzkumu měkkýšů (Mollusca: Gastropoda, Bivalvia) v okolí města Blatná v jihozápadních Čechách [Results of the faunistic survey of molluscs in the vicinity of Blatná town in south-western Bohemia]

2008 ◽  
Vol 7 ◽  
pp. 33-46
Author(s):  
Petr Bogusch ◽  
Libor Dvořák ◽  
Jaroslav Č. Hlaváč
Keyword(s):  
Czech Republic ◽  
Ecological Group ◽  
Freshwater Species ◽  
Forest Species ◽  
Steppe Species ◽  
Small Water ◽  
Freshwater Molluscs ◽  
Rare Elements ◽  
Western Bohemia ◽  
The Town

Results of the faunistic survey on molluscs in the vicinity of the town of Blatná (south-western Bohemia, Czech Republic) are presented. This research was carried out in 2004–2007 at 28 sites complemented by other older unpublished records. Altogether 87 species (76 gastropods, 11 bivalves) have been recorded that the freshwater molluscs represented the most abundant ecological group in this region (about 40% of all species recorded). However, the rare species (e.g. Aplexa hypnorum, Physa fontinalis, Pisidium obtusale) have been found usually in small water bodies while the majority of common freshwater molluscs was recorded predominantly in large and mid-sized ponds. The snail Gyraulus acronicus is the rarest freshwater species found only at one locality. Important proportion of investigated malacofauna consisted of wetland and floodplain species with rare elements such as Vertigo antivertigo, V. substriata, Euconulus praticola or even V. angustior, the former being protected in the whole Europe. Occurrence of this endangered species in the studied region represents one of the most important clusters of its populations in Bohemia. Only several forest species have been recorded, the species Acanthinula aculeata and Vertigo pusilla are of particular importance. Unique are finds of the steppe species Chondrula tridens on old slacking walls in the town of Blatná.

Tissue Extraction Methods for Metabolic Profiling of a Freshwater Bivalve,Elliptio complanata(Lightfoot, 1786)

2016 ◽  
Vol 33 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Jennifer L. Hurley-Sanders ◽  
Michael K. Stoskopf ◽  
Stacy A. C. Nelson ◽  
William Showers ◽  
J. Mac Law ◽  
...  
Keyword(s):  
Metabolic Profiling ◽  
Extraction Methods ◽  
Freshwater Bivalve ◽  
Tissue Extraction ◽  
Elliptio Complanata

Ammonia dynamics during and after prolonged emersion in the freshwater clam Corbicula fluminea (Müller) (Bivalvia: Corbiculacea)

1991 ◽  
Vol 69 (3) ◽  
pp. 676-680 ◽  
Author(s):  
Roger A. Byrne ◽  
Thomas H. Dietz ◽  
Robert F. McMahon
Keyword(s):  
Ammonia Excretion ◽  
Corbicula Fluminea ◽  
Freshwater Species ◽  
Protein Catabolism ◽  
Freshwater Bivalve ◽  
Ammonia Content ◽  
Ammonia Accumulation ◽  
Metabolic Switching ◽  
Clam Corbicula ◽  
Excretion Rates

Hemolymph ammonia content during emersion and ammonia fluxes on reimmersion were examined in the freshwater bivalve Corbicula fluminea (Müller). Hemolymph ammonia levels remained at pre-emersion levels over a 5-day emersion period at 25 °C, but thereafter levels increased prior to death. On resubmergence after 3 days emersion, the initial rates of ammonia excretion were low and took 15 h to reach maximum levels. Duration of emergence did not affect postemergence ammonia excretion rates in individuals emersed for less than 3–4 days. These results indicate a lack of ammonia accumulation in aerially exposed specimens. Rather, C. fluminea appeared to suppress protein catabolism during emergence and avoided ammonia accumulation. Death on emergence occurred coincidentally with an increase in ammonia accumulation. After reimmersion, the delay in development of ammonia efflux maxima may represent metabolic "switching" from catabolism dominated by nonprotein energy stores to one partially supported by protein. Suppression of protein catabolism in air is an adaptation to the prolonged and unpredictable emergence not previously reported for any freshwater species.

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