Cytological and cytochemical investigations of development from dormant gemmules of the marine sponge,Haliclona loosanoffi

Vernalized gemmules of the marine sponge Haliclona loosanoffi were cultured at 20°C, fixed at 24-hour intervals (0–11 days), and processed for light microscopy by using a variety of absorption and fluorescent staining methods. The cytochemistry and morphology of development were compared to the well-studied developmental patterns of freshwater sponges and to the patterns described in the marine sponge Suberites domuncula. The precocious development of H. loosanoffi gemmules involves early morphogenesis occurring within the unhatched gemmule, as opposed to the patterns in freshwater sponges, where most development occurs after the gemmule hatches. Definitive sponge tissue surrounding a single osculum is present 9 days after release from dormancy.     

Correlation of cyclic GMP and cyclic AMP immunofluorescence with cytochemical patterns during dormancy release and development from gemmules in Spongilla lacustris L. (Porifera: Spongillidae)

The spongillid freshwater sponges asexually produce an encapsulated dormant stage, the gemmule. With release from dormancy, internal, yolk-laden, binucleate thesocytes differentiate into histoblasts or archeocytes. The histoblasts emerging first from the gemmule form the initial pinacoderm of the hatching sponge. Immunohistochemistry was employed to examine the distribution of cyclic GMP (cGMP) and cyclic AMP (cAMP) following dormancy release and during gemmule germination and hatching in the freshwater sponge, Spongilla lacustris L. Cyclic nucleotide fluorescence patterns were analyzed in relation to the distribution of cytochemically demonstrable macromolecular constituents and intracellular organelles. Twenty-four hours following temperature-activated release from dormancy, cGMP fluorescence levels are elevated in thesocytes at the gemmule periphery prior to histoblast formation. The cAMP fluorescence in the gemmule also occurs first in those thesocytes differentiating into histoblasts. Cytochemical patterns in germinating gemmules are comparable with those described by Ruthmann ('65) and Tessenow ('69). However, cytochemically demonstrable events of cytodifferentiation follow the earlier appearance of cGMP and cAMP in the histoblast precursors by approximately 12 hours. In addition, cGMP appears to be associated with the membranes of cytoplasmic organelles, possibly lysosomes or lipid inclusions, in the region of vitelline platelets and with symbiotic algae. cAMP is located primarily on the membranes of the vitelline platelets and on membranes of vacuoles involved in forming the spicular skeleton These observations suggest that cGMP and cAMP are involved in the mobilization of nutrient reserves and in ion transport during dormancy release and development from gemmules in freshwater sponges.     

Gemmules of sponges from a warm lake

1. Two types of gemmules were found, each in a different species of sponge, from the warm monomictic Lake Kinneret: (i) clustered gemmules, sharing the pneumatic layer of the gemmular capsule and resembling gemmules of Eunapius ; (ii) gemmules that develop non-synchronously, containing amphidisc spicules within the gemmular capsule and resembling those of Ephydatia . Algal cells were not detected within either type of gemmule although they exist in the developed sponges.
2. Sponges began producing gemmules in the lake with the onset of lake drawdown and ceased when lake level was minimal. The gemmules hatched when the lake level began to rise.
3. Under experimental conditions gemmules hatched between 13 and 35 °C. Germination was optimal at 20–25 °C. Chilling of young gemmules prior to incubation at 25 °C improved germination rate.
4. The percentage of germinating dry gemmules diminished 4–6 months after their collection from the lake. None germinated after 10 months. Submerged gemmules maintained high viability with ageing (up to 100% germination 18 months after collection). Desiccation influenced gemmule viability over time, by both decreasing the percentage of germinating gemmules and increasing the lag time before onset of germination.
5. Gemmules kept in the dark germinated significantly less than those illuminated for 12 h day     

Gemmules of sponges from a warm lake

1. Two types of gemmules were found, each in a different species of sponge, from the warm monomictic Lake Kinneret: (i) clustered gemmules, sharing the pneumatic layer of the gemmular capsule and resembling gemmules of Eunapius ; (ii) gemmules that develop non-synchronously, containing amphidisc spicules within the gemmular capsule and resembling those of Ephydatia . Algal cells were not detected within either type of gemmule although they exist in the developed sponges.
2. Sponges began producing gemmules in the lake with the onset of lake drawdown and ceased when lake level was minimal. The gemmules hatched when the lake level began to rise.
3. Under experimental conditions gemmules hatched between 13 and 35 °C. Germination was optimal at 20–25 °C. Chilling of young gemmules prior to incubation at 25 °C improved germination rate.
4. The percentage of germinating dry gemmules diminished 4–6 months after their collection from the lake. None germinated after 10 months. Submerged gemmules maintained high viability with ageing (up to 100% germination 18 months after collection). Desiccation influenced gemmule viability over time, by both decreasing the percentage of germinating gemmules and increasing the lag time before onset of germination.
5. Gemmules kept in the dark germinated significantly less than those illuminated for 12 h day     

Scanning electron microscopy of taxonomic diagnostic criteria of the freshwater sponge,Heteromeyenia tubisperma (Potts, 1881) (Porifera : Spongillidae)

Taxonomic diagnostic criteria of the spongillid freshwater sponge, Heteromeyenia tubisperma (Potts, 1881) were examined using scanning electron microscopy. The species is characterized by a gemmule which bears an unusually long, prominent porous tube. The application of SEM to the systematic studies of the freshwater sponges provides diagnostic capabilities not available with the light microscope. It is desirable that a key, coupled with a reference atlas of scanning electron micrographs illustrating taxonomic diagnostic criteria of freshwater sponge species, particularly utilizing type specimens, be developed.     

Molecular phylogeny of the freshwater sponges in Lake Baikal

The phylogenetic relationship of the freshwater sponges (Porifera) in Lake Baikal is not well understood. A polyphyletic and/or monophyletic origin have been proposed. The (endemic) Baikalian sponges have been subdivided into two families: endemic Lubomirskiidae and cosmopolitan Spongillidae. In the present study, two new approaches have been made to resolve the phylogenetic relationship of Baikalian sponges; analysis of (1) nucleotide sequences from one mitochondrial gene, the cytochrome oxidase subunit I (COI) and of (2) one selected intron from the tubulin gene. Specimens from the following endemic Baikalian sponge species have been studied; Lubomirskia baicalensis , Baikalospongia intermedia, Baikalospongia recta , Baikalospongia bacillifera and Swartschewskia papyracea . They are all grouped to the family of Lubomirskiidae. Sequence comparisons were performed with the ubiquitously distributed freshwater sponge Spongilla lacustris (family Spongillidae) as well as with one marine sponge, Suberites domuncula . A sequence comparison * * The sequences reported here are being deposited in the EMBL data base. of the mitochondrial COI gene revealed a monophyletic grouping of the endemic Baikalian sponges with S. lacustris as the most related species to the common ancestor. The sequences of the COI gene from B. recta , B. intermedia , B. bacillifera and L. baicalensis were found to be identical and separated from those of S. lacustris and S. papyracea . In a second approach, the exon/intron sequences framing the intron‐2 of the sponge tubulin gene were chosen for the phylogenetic analysis. The intron sequences were aligned and used for construction of a phylogenetic tree. This analysis revealed again a monophyletic grouping with S. lacustris as the closest related species to the common ancestor. It is concluded that the Baikalian sponges, which have been studied here, are of monophyletic origin. Furthermore, the data suggest that the endemic species S. papyracea is the phylogenetically oldest, extant, endemic Baikalian sponge species.     

Clypeatula cooperensis gen. n., sp. n., a new freshwater sponge (Porifera,Spongillidae) from the Rocky Mountains of Montana,USA

A new genus and species of freshwater sponge, Clypeatula cooperensis , collected from three lakes in the Northern Rocky Mountains of Montana, USA, are described. The sponge grows as a hard, disc-shaped encrustation on the undersides of rocks and logs. It lacks microscleres and has amphioxeal megascleres that often show a slight midregion bulb and are usually covered with short, conical spines except at their tips. The sponge is also non-gemmulating, overwintering in a regressed state in which choanocyte chambers are reduced in number. Phylogenetic analyses of complete 18S rDNA sequences of C. cooperensis , Ephydatia muelleri , Spongilla lacustris and Eunapius fragilis suggest that C. cooperensis is more closely related to Ephydatia muelleri than to Spongilla lacustris or Eunapius fragilis . Our data, nonetheless, do not rule out the possibility that C. cooperensis is more closely related to the non-gemmulating sponges of Lake Baikal (Russia) than it is to Ephydatia muelleri . These phylogenetic analyses support the erection of a new genus, the monophyly of freshwater sponges belonging to the families Spongillidae and Lubomirskiidae, and the monophyly of demosponges.     

Role of cAMP in the release from dormancy of freshwater sponge gemmules.

The role of 3′5′-cyclic AMP (cAMP) in the release from dormancy of gemmules from the freshwater sponge Spongilla lacustris was investigated. During the first 2 hr of germination a significant decrease in the gemmule cAMP content was observed. In the presence of amino-phylline, at concentrations which inhibit the gemmule-cAMP-phosphodiesterase, the cAMP content did not decrease and germination was arrested at a stage prior to nuclear separation and cell division. The findings suggest that inhibition of cell division by cAMP participates in the control of dormancy.     

Gemmules of Anheteromeyenia ryderi and Heteromeyenia tubisperma (Porifera: Spongillidae) from southern New England undergo diapause

SUMMARY. 1. The annual cycle of the freshwater sponge, Anheteromeyenia ryderi , was studied in a seepage pond in Connecticut. The adult form of the sponge persisted throughout the year, although some specimens at the edge of the pond degenerated by late summer. During the middle of the winter, adult sponges had a simplified tissue morphology with reduced numbers of flagellated chambers.
2. Gemmules of A. ryderi were also present during all seasons. Gemmule germination occurred during the spring, and some specimens produced new gemmules by late spring.
3. The gemmules of A. ryderi underwent a protracted diapause which was broken under both natural and laboratory conditions by several months exposure to low temperatures (≤5°C).
4. The gemmules of Heteromeyenia tubisperma were also shown to undergo diapause, but in this case diapause was broken by a relatively short cold treatment (1 month).     

Cytochemical Observations of Gemmule Development in Eunapius fragilis (Leidy): Porifera; Spongillidae

The cytology and cytochemistry of gemule formation in the freshwater sponge Eunapius fragilis (Leidy) is investigated. The aggregation of ameboid cells which initiates gemmulation is composed of three distinct cell types, two of these fitting the morphological criteria of the archeocyte class. The third cell type, the granular cell, is a differentiated cell type which undergoes cytolysis during gem-mule coat synthesis. Following early polarisation of the aggregate into an internal reproductive area and a peripheral coat region, a structurally and chemically heterogeneous gemmule coat is synthesis-ed. The coat is formed through secretory activities involving several cell types including, possibly, the internal endothelium. The coat is composed of "collagenous" fibers embedded in a matrix of varying degrees of density–showing close structural and cytochemical similarities to vertebrate chondroid tissue. Vitelline platelets of thesocytes of E. fragilis do not cytochemically resemble any previously reported vitelline inclusions from other sponges. Outer valves of the platelets contain components stained by basic dyes at acidic pH which are not extracted by RNase. Distinct differences in developmental processes and morphological–including cytochemical–characteristics of gemmules of different spongillid species are apparent.     

Cellular src gene product detected in the freshwater sponge Spongilla lacustris.

Serum from Rous sarcoma virus tumor-bearing rabbits immunoprecipitated from extracts of the freshwater sponge Spongilla lacustris a tyrosine-specific protein kinase with characteristics similar to the chicken pp60c-src kinase activity. An immune competition assay confirmed the relationship between the protein from sponges and viral pp60v-src.     

Cold hardiness of the green gemmules of Spongilla lacustris L. (Porifera: Spongillidae)

Most green gemmules of Spongilla lacustris survived enclosure in ice at –20 °C for up to 30 days; however, their rate of germination at 20 °C was less rapid than that of control gemmules. The length of time spent at low temperature had little effect on gemmule survival. In contrast, repeated cooling to –20 °C and warming to 4 °C led to a progressive decline in gemmule viability. These results indicate that cold injury occurs primarily during transitions between high and low temperatures.     

Trophic ecology of a freshwater sponge (Spongilla lacustris) revealed by stable isotope analysis

The vital roles that sponges play in marine habitats are well-known. However, sponges inhabiting freshwaters have been largely ignored despite having widespread distributions and often high local abundances. We used natural abundance stable isotope signatures of carbon and nitrogen (δ ¹³C and δ ¹⁵N) to infer the primary food source of the cosmopolitan freshwater sponge Spongilla lacustris. Our results suggest that S. lacustris feed largely on pelagic resources and may therefore link pelagic and benthic food webs. A facultative association between S. lacustris and endosymbiotic green algae caused S. lacustris to have significantly depleted carbon and nitrogen signatures that may reflect carbon and nitrogen exchange between sponges and their symbiotic algae. Isotopic data from specialist sponge consumers demonstrated that sponges hosting zoochlorellae were the major component of the diet of the spongillafly Climacia areolaris and the sponge-eating caddisfly Ceraclea resurgens suggesting that the symbiosis between freshwater sponges and algae is important to sponge predator trophic ecology. Our results help define the role of sponges in freshwater ecosystems and shed new light on the evolution and ecological consequences of a complex tri-trophic symbiosis involving freshwater sponges, zoochlorellae, and spongivorous insects.     

Survival of the gemmules of Anheteromeyenia ryderi (Potts) following aerial exposure during winter in New England

Gemmules of Anheteromeyenia ryderi survived 24 h exposure to air temperatures as low as –20 °C under laboratory conditions. Drying the gemmules of A. ryderi at 5 °C under laboratory conditions resulted in a reduced viability and a slower germination rate following rehydration compared with undried control gemmules. Only 25% of the gemmules germinated after drying for one month. Up to 25% of the gemmules of A. ryderi that were tested survived aerial exposure from early November to early April when a pond in Connecticut inhabited by this sponge was drained. During this period air temperatures dropped to as low as –16 °C. Continued aerial exposure of the gemmules during the summer resulted in nearly complete gemmule mortality.     

Phylogenetic position of sponges from Chagytaĭ and Tore-Khol' lakes

Morphological and molecular genetic data for freshwater sponges from the lakes of Tuva Depression, Baikalospongia dzhegatajensis (Rezvo, 1936), forms Dzh05 and Dzh06, from Chagatai Lake, as well as forms TKhl and TKh2, from the Lake Tore-Khol, were obtained and examined. In the sponges examined, which on phylogenetic tree clustered together with the Ephydatia fluviatilis (Linneaus, 1758) sponge from the family Spongillidae, the ITS rDNA regions were sequenced. Comparison of highly variable interal spacer regions of the mitochondrial genome was performed using corresponding sequences of three sponges from the family Spongillidae (E. fluviatilis, E. muelleri and Spongilla lacustris), sponges from the Chagatai and Tore-Khol lakes (Dzh06 and TKh2) with an unknown status, and sponges from the Baikalian family Lubomirskiidae. Minimum genetic differences were observed between E. fluviatilis, Dzh06, and TKh2 (from 0.003 to 0.01% of nucleotide substitutions), while maximum differences were found between the species of Lubomirskiidae and Spongillidae (from 0.928 to 2.06%). The data obtained indicated that sponges from Chagatai and Tore-Khol lakes were most close to E. fluviatilis.     

The influence of an eucaryotic intranuclear cell parasite on the production of gemmules inEphydatia fluviatilis (Porifera,Spongillidae)

Summary A prerequisite for the production of gemmules is the presence of intact archaeocytes and trophocytes, which give rise to the thesocytes with which the gemmule is eventually filled. The coat enclosing the gemmule requires spongioblasts for its formation and incorporates amphidisk spicules, which develop in amphidiskoblasts. The cell parasite, the development of which is described here, infects mainly archaeocytes but also spongioblasts and amphidiskoblasts. Even a moderate infection results in significant malformation of the gemmule covering. In the thesocyte nucleus, the parasite can survive the resting phase of the gemmule. After the gemmule has hatched, the parasite, again in the virulent form, is present in the young, developing sponge. The parasite may be a microsporidian of the primitive type, close to the genusMetchnikovella, which typically occurs in gregarines.Abbreviations for the microscopic procedures PhM phase-contrast microscopy - TEM transmission electron microscopy - SEM scanning electron microscopy     

Histology and histochemistry of developing outgrowths of Corvomeyenia carolinensis harrison (Porifera: Spongillidae)

Laboratory-reared outgrowths of the freshwater sponge Corvomeyenia carolinensis Harrison were examined using histological and histochemical techniques, supplemented by phase contrast observations of cellular behavior. The tissue and cellular components of the spongillid outgrowth region were defined in terms of function and morphogenic state. Archeocytes differ considderably, in both histochemical and morphological characteristics, from other cell types of the adult sponge, being histochemically similar to stem cells reported from a variety of developmental series. Archeocytes exhibit cytological characteristics of unspecialized cells capable of high levels of synthetic activity while other cell types of C. carolinensis, for the most part, can be characterized as fully differentiated cells displaying more restricted synthetic capabilities but often accumulating neutral mucoproteins. The presence of aggregates of amebocytes, not identifiable as archeocytes and possibly engaged in gemmule formation, is discussed in terms of current concepts of gemmulation and cellular developmental capabilities in sponges.     

Nutrient translocation from green algal symbionts to the freshwater sponge Ephydatia fluviatilis

The symbiosis between the freshwater sponge Ephydatia fluviatilis and a chlorella-like green alga is not obligate and only occurs when the sponge grows in the light. The algae accumulate intracellular pools of sucrose and glucose and translocate between 9 and 17% of the total photosynthate to the host. The principal product translocated is glucose which is fed directly into the sponge metabolic pool. White sponges transplanted back into the river in the shade grew logarithmically with a mean doubling time of 12 days. Sponges transplanted into illuminated habitats did not grow. It is unknown how the sponge acquires its algal symbiont.     

The effects of cadmium and mercury on gemmule formation and gemmosclere morphology in Ephydatia fluviatilis (Porifera : Spongillidae)

A laboratory study of the effects of cadmium and mercury on the freshwater sponge, Ephydatia fluviatilis, was conducted. Sponge cuttings were exposed to concentrations of cadmium or mercury which ranged from 1.000 to 0.001 ppm for one month. The responses exhibited by the specimens resulted in four groups characterized as follows: sponge colony survived and produced gemmules with normal gemmoscleres; sponge colony survived and produced gemmules with malformed gemmoscleres; sponge colony survived but did not gemmulate; sponge colony died. A direct discriminant functions analysis of the four sponge groups, metal concentrations and other chemical data established a highly significant correlation between increasing metal concentrations and amount of damage to the sponge.