Spongilla Lacustris Research Articles

Colonization and evolution of lakes on the central Norwegian coast following deglaciation and land uplift 9500 to 7800 years B.P.

Invertebrate colonization of lakes following the uplift of land from the sea was studied in four lakes, currently situated between 39 and 24 m a.s.l., on the central Norwegian coast. The lakes were isolated from the sea between 9500 and 7700 years B.P. Animal and algal remains picked from core samples showed that the first colonizers preserved as fossils were usually members of the Chironomidae, Daphnidae/Chydoridae, Acarina, Porifera (Ephydatia mulleri and Spongilla lacustris), Bryozoa (Cristatella mucedo and Plumatella spp.) and Charophyta (Chara sp.). Of the chironomids, the genus Chironomus was present in the oldest lacustrine layers of all four lakes, but other genera recorded at the marine/lacustrine boundary were Dicrotendipes, Procladius (?), Einfeldia, Microtendipes, and Glyptotendipes. Remains of the caddis fly family Limnephilidae were also present in the earliest lacustrine sediments in Kvennavatnet and Kvernavatnet. The oldest invertebrate fauna is typical for mesotrophic lakes. However, chironomids and mites have been present in this area from at least about 10 500 years B.P. A diverse chironomid community was established between 300 and 800 years after isolation from the sea at Kvernavatnet on the island of Hitra, while only between 80 and 120 years passed before a comparably diverse community developed at Kvennavatnet on the mainland coast. A similar development of the invertebrate fauna occurred in Kvennavatnet, Kvernavatnet and Storkuvatnet. However, Litjvatnet deviates greatly from the ‘normal’ pattern because a tsunami disturbed the bottom sediments and fauna. The tsunami, a gigantic sea wave, was caused by a submarine slide from the Norwegian continental slope. It reached Litjvatnet, today located 24 m a.s.l., but was not traced in Storkuvatnet at 30 m a.s.l. This event happened about 7200 years B.P.

Distribution and ecology of freshwater sponges in Connecticut

A survey of Connecticut lakes and rivers revealed the presence of 7 species of freshwater sponge: Spongilla lacustris, Ephydatia muelleri, Eunapius fragilis, Anheteromeyenia ryderi, A. argyrosperma, Corvomeyenia carolinensis, and Corvospongilla novaeterrae in order of decreasing frequency of occurrence. Corvomeyenia carolinensis has not been reported previously beyond its type locality in South Carolina. In addition, microscleres of Spongilla lacustris, Anheteromeyenia-like megascleres, Ephydatia muelleri-like megascleres, and smooth megascleres (amphioxeas), which could not be assigned to a particular species, were found in surface sediments from lake cores. Spongilla lacustris inhabiting small rivers produced brown, thick-capsuled gemmules during the summer and yellow, thin-capsuled gemmules during the fall. The thick-capsuled gemmules, but not the thin-capsuled gemmules, are tolerant of desiccation; and populations of Spongilla lacustris and Ephydatia muelleri survived severe drying of their habitats during the summer.

New Records of Freshwater Sponges (Porifera) for Southern Lake Michigan

Four species of freshwater sponge were identified in southern Lake Michigan: Spongilla lacustris (Linneaus), Eunapius fragilis (Leidy), Ephydatia fluviatilis (Linneaus), and Ephydatia muelleri (Lieberkuhn). Samples were collected from artificial substrates in Calumet (IL), Hammond (IN), and Michigan City (IN) harbors and represent the first reports of sponges in these waters. Numerical densities for all species combined were as high as 698 sponge colonies/m 2 on the iron hull of the permanently moored 110-m-long ship Milwaukee Clipper in Hammond Harbor. These densities were lowest at 1-m depth and greater at 2- and 3-m depths. A positive correlation (r 2 = 0.74) was found between the density of sponge colonies and the angle of the hull as it changed from near vertical at the water line to overhanging at greater depth (toward the keel). Ephydatia muelleri was the most common species based on frequency of occurrence and percent surface area covered. Observations of epizoic growth of sponges on live zebra mussels ( Dreissena polymorpha Pallas) suggest that an ecological interaction exists between these two groups of organisms on these artificial substrates.

Experimental and field studies on the effect of selected heavy metals on three freshwater sponge species: Ephydatia fluviatilis, Ephydatia muelleri and Spongilla lacustris

The present work is the first study on the effects of metals on freshwater sponges, based on field and laboratory experiments. Three species, Ephydatia fluviatilis. Ephydatia muelleri and Spongilla lacustris were implanted in variously polluted natural sites. After one month, they showed a substantial growth in spite of high metal levels in the water for Ba, Cd, Cr, Mn, Mo, Ni, Pb or Zn according to the site of transfer. Different spicule malformations were observed in specimens according to the implantation site. The quantification of their metal content showed that at the end of the experiment, sponges had accumulated many heavy metals. Some correlation was found between the metal distribution in sponges and in the ambient water. In most cases, accumulation was of the same order of magnitude as in the sediment. Energy-dispersive spectrometry (EDS) and wavelength-dispersive spectrometry (WDS) analyses revealed that metals were not accumulated in the spicules but in the organic skeleton and living tissue. In vitro experiments established that Pb was more toxic than Cu and Zn and that S. lacustris was the least sensitive of the three species. Our results showed that, in their natural habitat, freshwater sponges could grow at metal concentrations higher than the threshold concentration measured in the laboratory.

Deep Diapause and the Influence of Low Temperature on the Hatching of the Gemmules of Spongilla lacustris (L.) and Eunapius fragilis (Leidy)

Yellow, thin-capsuled gemmules of Spongilla lacustris undergo deep diapause. This is the first demonstration of deep diapause in gemmules of this species. Exposure to low temperature promotes emergence from diapause. Evidence suggesting that low temperature may be a necessary condition for breaking deep diapause in sponge gemmules is strongest for Eunapius fragilis. Gemmules stored at 30 C for 3 weeks and then maintained continuously at 20? C for 27 weeks did not hatch, whereas gemmules exposed to 3? C for 18 weeks before they were placed at 20? C hatched within 4 days. Finally, green, thin-capsuled gemmules of Spongilla lacustris and gemmules of Eunapius fragilis eventually hatch at 3? C, but only after a period of several months and only under uncrowded conditions. Additional key words: sponges, dormancy Many freshwater and some estuarine/marine sponges produce dormant propagules called gemmules. Each gemmule consists of a mass of cells enclosed by a collagenous capsule that in many cases contains siliceous spicules. Frequently gemmules are the only form of the sponge that persists during adverse environmental conditions. With the return of favorable conditions, the gemmules hatch and give rise to active sponges (Simpson & Fell 1974; Simpson 1984; Fell 1993; Pronzato & Manconi 1994). Gemmule dormancy is of two general types, quiescence and diapause. Quiescence is imposed by unfavorable environmental conditions, including low temperature, and ends when favorable conditions recur (Rasmont 1954, 1962; Mukai 1980). On the other hand, diapause is imposed by an endogenous mechanism even in the presence of favorable environmental conditions. The breaking of diapause often requires or is at least accelerated by exposure to low temperature and may be followed by a period of gemmule quiescence (Rasmont 1955, 1962; Mukai 1980; Fell 1987a). Although there have been only few studies of sponge dormancy, it appears that the depth of gemmule diapause is highly variable both among and within species. Gemmules undergoing shallow diapause hatch rapidly at warm temperatures (around 20? C) after a few days exposure to low temperature (around 5? C) and may even hatch more slowly at warm temperatures without exposure to cold, whereas gemmules in deep diapause require one or more months of cold treatment before they are capable of hatching at warm temperatures (Fell 1993). Low temperature was believed to keep nondiapausing gemmules and gemmules that have emerged from diapause in a quiescent state more or less indefinitely (Rasmont 1963; Fell 1987a). This may be true for gemmules stored under crowded conditions; however, the gemmules of some sponges do hatch eventually at low temperature under field and/or laboratory conditions (Simpson & Gilbert 1973; Barbeau et al. 1989; Fell 1994). The gemmules of Spongilla lacustris are of two types. In thick-capsuled gemmules, the brown, threelayered capsule contains spicules and a single micropyle. The cells possess few, if any, symbiotic zoochlorellae and appear white. In thin-capsuled gemmules, the single-layered capsule features multiple micropyles and no spicules (Gilbert & Simpson 1976). These gemmules range in color from bright green to golden yellow to white, reflecting both the abundance of green symbiotic algae (Williamson 1979) and the amount of yellow pigment in the capsule. Thick-capsuled gemmules of Spongilla lascustris are produced in small numbers by a few individuals during the summer, in the basal regions of encrusting specimens or along the axes of thick branches. Thin-capsuled gemmules are formed in large numbers throughout the body of the sponge during the fall; and all of the individuals within a population gemmulate at this time (Simpson & Gilbert 1973; Gilbert & Simpson 1976). Some evidence suggests that the two gemmule types of Spongilla lacustris may undergo different types of dormancy. Whereas green, thin-capsuled gemmules are quiescent, This content downloaded from 157.55.39.162 on Thu, 11 Aug 2016 05:21:04 UTC All use subject to http://about.jstor.org/terms

Retinoic acid acts as a morphogen in freshwater sponges

Summary The effect of retinoic acid [RA] on the morphogenesis of freshwater sponges (Spongilla lacustris, Ephydatia fluviatilis, Ephydatia muelleri) was studied. At a concentration of 2 μM, RA had no overt effect on pinacocytes and choanocytes but had already altered mesohyl cell movement and adhesion after 1 h treatment. It interfered with morphogenesis of sponges developing both from larvae and gemmules, inhibiting the formation of the aquiferous system, and promoting formation of reduction bodies. The same was observed in treatment of functional sponges with RA. We conclude that RA induces modifications in mesohyl cell adhesion and interaction, analogous to that observed in induction of reduction bodies formation or gemmulogenesis.

Photosynthesis by symbiotic algae in the freshwater sponge, Spongilla lacustris

Photosynthesis by symbiotic algae in the freshwater sponge, Spongilla lacustris

Ingestion, digestion, and egestion in Spongilla lacustris (Porifera, Spongillidae) after pulse feeding with Chlamydomonas reinhardtii (Volvocales)

The route followed by food particles in Spongilla lacustris was clarified by light and electron microscopic examination of sponges fed with Chlamydomonas reinhardtii. The algal cells are phagocytosed by prosendopinacocytes and choanocytes. After some time they are transferred to archaeocytes, amoebocytes, and lophocytes. Changes in algal structure during digestion were observed and the egestion of algal remnants was documented in life for the first time. In light micrographs, digestion of the algal cells is manifest first in shrinkage of the cells, then in disintegration to form several spherical green fragments 2–3 μm in diameter, and finally, after 12–18 h, in a reddish brown discoloration of the fragments. Signs of the digestive process in electron micrographs include disappearance of the cell-wall layers, the flagella, and the pyrenoid and its starch sheath, as well as a progressive increase in the density of the cytoplasm and karyoplasm.

Preparation and karyotype analysis of mitotic chromosomes of the freshwater sponge Spongilla lacustris.

The present study documents for the first time the karyotype and mitotic chromosomes of a sponge. For the studies the freshwater sponge Spongilla lacustris (Lin. 1758) was used. Its karyotype comprises nine different chromosome pairs ranging in size from 2.1 to < or = 0.7 microns. Changes in size and shape of the chromosomes during the progression of mitosis are documented both light and electron microscopically. The data reveal that the lowest multicellular eukaryotes, the sponges, have already reached a high level of evolution of the mitotic mechanism.

Life Cycle, Reproduction, and Ecology of Freshwater Sponges in a South Carolina Pond. I. Life Cycle and Reproduction of Spongilla lacustris

Life Cycle, Reproduction, and Ecology of Freshwater Sponges in a South Carolina Pond. I. Life Cycle and Reproduction of Spongilla lacustris

Life cycle of Spongilla lacustris (Porifera, Spongillidae): a cue for environment-dependent phenotype

We studied the life cycle and growth of Spongilla lacustris in a stream with three distinct habitats. Sponge populations in the habitats exhibited different adaptive strategies. Growth forms of S. lacustris ranged from encrusting to digitate and branched. Environmental factors controlled the appearance of each growth form. In the most hospitable habitat, a variety of colonization strategies and different growth forms were present. In the less hospitable habitat growth was restricted to small and encrusting specimens. In the optimal habitat, the largest and most luxuriant specimens developed. Gemmulation and hatching were dephased among specimens in the three habitats; hence gemmules were present for long periods of time. S. lacustris was found capable of displaying two life strategies: r in the short run, K in the long run.

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.

Cytoskeletal organization and cell organelle transport in basal epithelial cells of the freshwater sponge Spongilla lacustris

Different antibodies against actin, tubulin and cytokeratin were utilized to demonstrate the spatial organization of the cytoskeleton in basal epithelial cells of the freshwater sponge Spongilla lacustris. Accordingly, actin is localized in a cortical layer beneath the plasma membrane and in distinct fibers within the cytoplasmic matrix. Microtubules exhibit a different distributional pattern by radiating from a perinuclear sheath and terminating at, the cell periphery; in contrast, intermediate filaments are lacking. Cytoplasmic streaming activity was studied by in-vivo staining of mitochondria and endoplasmic reticulum by means of fluorescent dyes. Single-frame analysis of such specimens revealed a regular shuttle movement of mitochondria and other small particles between the cell nucleus and the plasma membrane, which can be stopped in a reversible manner with the use of colcemid or colchicine but not with cytochalasin D. The results point to the microtubular system as a candidate for cell organelle transport, whereas the actomyosin system rather serves for changes in cellular shape and motility.

Variability of the immune response in freshwater sponges

AbstractThe variability of the immune response of four species of freshwater sponges, common in Belgium, Ephydatia fluviatilis, Ephydatia mulleri, Spongilla lacustris, and Eunapius fragilis, has been analyzed at the cellular level.For each species, strains, which are the collection of all the sponge individuals able to fuse compatibly their aquiferous system, were collected in natural ponds and isolated.In most cases, the general immune response corresponds to a three‐step process restricted to the zone of contact. This process includes: the fusion of the sponges coming into contact, a local cell accumulation, and the separation of the alien sponges.The variability of the immune reaction mainly concerns the existence and the duration of the fusion step and the possible secretion of a collagen barrier between the separated alien sponges. In contrast, for all the combinations studied, the accumulated cells differentiate and organize themselves in two facing layers of pinacocytes.In some allocombinations, involving S. lacustris strain δ, a general reaction was recorded. In these pairings, after the initial fusion, the alien sponges undergo a temporary involution followed by the segregation and reconstitution of two separated functional sponges.Our exhaustive analysis leads to the conclusion that the alloimmune responses vary according to the species and even within a single species, according to the strains paired. In contrast, all the xenocombinations undergo a similar process consisting in the direct and complete separation of the sponges.These results demonstrate the possibility for freshwater sponges to diversify their responses to nonself and consequently to discriminate between different nonself.

Ultrastructural investigation of spermatogenesis in Spongilla lacustris and Ephydatia fluviatilis (Porifera, Spongillidae)

Spermatogenesis of the spongillids investigated here is similar in Spongilla lacustris and Ephydatia fluviatilis and proceeds, on the whole, as in other Eumetazoa. Sponges however lack true sex organs, the germ cells developing from somatic cells. The male germ cells originate in spongillids from choanocytes and the female ones from archaeocytes. In Spongilla lacustris single choanocytes leave the flagellated chambers and transform into spermatogonia; in Ephydatia fluviatilis they result from differential cell division. The spermatogonia gather in distinct mesenchyme regions and are surrounded by cyst-building cells. Thus spermatocysts are built in which spermatogenesis proceeds. The spermatogonia in the spermatocysts differentiate into flagellated spermatocytes of I. order. In this process, the early appearance of the flagellum and its mode of formation are uncommon. The following meiotic divisions generate spermatocytes of II. order in the first step and spermatids in the second. In both developmental stages the cells remain connected by cytoplasmic bridges. In the subsequent spermiocytogenesis the cytoplasm of the spermatids is reduced. The reduced parts of the cytoplasm appear as cell fragments in the lumen of the spermatocysts and are eventually ingested by the cystwall cells. The mature spermatozoa arrange in the spermatocysts in a characteristic pattern. Later the spermatocysts open into the excurrent canal system and the spermatozoa leave the sponge with the egestive water stream.

Microscopical aspects on symbiosis of Spongilla lacustris (Porifera, Spongillidae) and green algae

When growing in the sunlight, some specimens of Spongilla lacustris are coloured green due to the presence of symbiotic unicellular chlorellae. The algae live inside most sponge cells. The chlorellae were extracted from green sponges, cultivated, added to algae-free sponges and fixed after different incubation times. In this way the uptake of the algae, their distribution and their final whereabouts in the mesenchymatic cells could be followed by in vivo microscopy, phase-contrast microscopy and electron microscopy. A few minutes after addition, the chlorellae can be found inside the choanocyte chambers. Here they are taken up by the cell bodies and collars of the choanocytes. Pinacocytes are also involved in the uptake. The distribution of algae results from a specific transmission from the donor cell to the receiver cell. The chlorellae are not released from their host vacuoles until they are extensively enclosed by the cell taking them up. Six hours after addition, all sponge cells contain algae except granulocytes, microscleroblasts, the pinacocytes of the peripheral rim region and those of the pinacoderm. The chlorellae are able to divide inside the sponge cells.

Steroids in porifera, sterols from freshwater sponges Ephydatia fluviatilis (L.) and Spongilla lacustris (L.)

1. 1. The sterols of the freshwater sponges Ephydatia fluviatilis and Spongilla lacustris were isolated and characterized by reverse phase HPLC, silver nitrate-silica gel TLC, mass spectrometry and 1H NMR. 2. 2. Ephydatia fluviatilis and S. lacustris have rather similar sterol composition and contain almost exclusively Δ 5-sterols. Cholesterol is the major sterol. In addition to the Δ 5-sterols E. fluviatilis contains a small amount of 24-methyl-5α-cholestan-3β-ol. 3. 3. The C-24 configuration of 24-alkyl sterols was determined. Sterols with the 24β configuration predominate over the 24α epimers. 4. 4. A summary on uncommon sterols in sponges is reported.

Canal systems and choanocyte chambers in freshwater sponges (Porifera, Spongillidae)

The spongillid species Spongilla lacustris and Ephydatia fluviatilis possess choanocyte chambers of the classical eurypylous type. They are surrounded by the mesenchymal tissue and connected to the incurrent canal system by prosopyles and to the excurrent canal system by wide apopyles. Each apopyle is sealed against spaces between the basal choanocyte collar parts by a ring of uniflagellated cone cells. The functional aspects of the choanocyte chamber and canal structure are discussed.

Logical Synthesis of an Animals Environment - Sponges to Non-Human Primates .1. Primitive Terms and Definitions

This paper is the first in a series on the environment of the freshwater sponge, Spongilla lacustris, the rat tapeworm, Hymenolepis diminuta, the common octopus, Octopus vulgaris, the cane toad, Bufo marinus, and the chimpanzee, Pan troglodytes. A new version is given of the formal symbolic definition of total environment, which was published by Niven (Erkenntnis, 1982, 17, 307-20). Informal defining equations are then presented, with examples from the environments of the five species of the study.

The development of Spongilla lacustris from the oocyte to the free larva (Porifera, Spongillidae)

During June and July oocytes appear in well-developed specimens of Spongilla lacustris. These differentiate from archeocytes, and during the first growth phase they reach a diameter of ca. 50 μm. At this time each oocyte is enclosed in a single-layered follicle epithelium, which is retained until emergence of the larva.