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At least 19 recordsLinked to original sources
PubMed1975

Cytological examination of reduction bodies of Corvomeyenia carolinensis Harrison (porifera: spongillidae).

Freshwater sponges, Corvomeyenia carolinensis Harrison, were placed into tap water to induce degenerative reduction body formation. Reduction bodies were examined using light and electron microscopy in order to define their histochemical and ultrastructural characteristics. The reduction body of freshwater sponges is an extremely simple developmental system consisting primarily of an archeocyte reserve delimited by a simple squamous pinacoderm. The freshwater sponge reduction body displays many similarities to overwintering phases of marine sponges. The system presents an unusually straightforward vehicle for investigations of degeneration and regeneration as processes in developmental biology and may represent a reasonable vehicle in which to examine the process of the genesis of lysosomes.

Animals↗
PubMed1992

An analysis of partial 28S ribosomal RNA sequences suggests early radiations of sponges.

Sequences from the 5' end terminal part of 28S ribosomal RNA were obtained and compared for 22 animals belonging to all diploblastic phyla and for a large number of representatives of triploblastic Metazoa and protists. Phylogenetic analyses undertaken using different methods showed deep radiations of phyla such as Ctenophora, Cnidaria and Placozoa but also for groups of Porifera of low taxonomic rank. Short internodes between these radiations suggested an early rapid diversification of diploblasts. A long internal branch preceding the diversification of all triploblasts analyzed could be explained either by a long period with a single ancestor or by the extinction of the earliest triploblastic radiations. Finally some unexpected relationships were revealed among Porifera.

Animals↗
PubMed1977

Origins of the nucleate organisms.

A theory regarding the early evolution of the eukaryotes is presented. It is proposed that the eukaryotes evolved through the successive stages: amoeba, flagellate, sexual flagellate. It postulated that sexuality emerged only once. A scheme relating evolution of the whiplash and tinsel forms of the flagellum to the evolution of sexuality is presented. It is suggested that sexuality first appeared in organisms capable of producing both forms of the flagellum. The phylogeny supports the hypotheses that the flagellum developed from the spindle system, and that the nucleate algae evolved from protozao through symbiosis with photosynthetic organisms related to the blue-green bacteria. It is consistent with the hypothesis that the mitochondrion was acquired by symbiosis. The phylogeny provides clearer definitions for kingdoms, and indicates the separation into seven kingdoms, as follows: Monera, Protozoa, Algae, Fungi, Porifera, Plantae, Animalia.

Animals↗
PubMed1992

Multiple src-related kinase genes, srk1-4, in the fresh water sponge Spongilla lacustris.

In one of the simplest metazoan organisms, the sponge Spongilla lacustris, at least four different src-related kinase genes (srk1-4) are expressed, all of which show a high degree of similarity to the c-src genes of vertebrates. Whereas srk2 and srk3 are clearly unrelated at the nucleic acid level, srk1 and srk4 share identical sequences in the 5' parts of their cDNAs. The cloning of several primer extension clones and genomic polymerase chain reaction experiments confirmed the hypothesis of an alternative splicing of tandemly arranged carboxy-terminal parts of srk1 and srk4. The genomic sequence encoding both proteins was found to be interrupted at the splice point by an intron which is located in the same position as one of the introns in the chicken src gene, which is the only gene conserved in invertebrates and vertebrates. All four srk genes are expressed in adult sponges as mRNA transcripts of about 2.2 kb. Tyrosine kinase activity of a src-related kinase could be detected in adult sponges but not in their resting form (gemmulae), and may reflect the activity of the srk protein products. Spongilla lacustris is the simplest organism from which a protein tyrosine kinase gene has been isolated. The presence of at least four such genes in the evolutionary ancient and primitive phylum Porifera suggests that tyrosine kinase genes arose concomitantly with or shortly after the appearance of multicellular organisms and that their activity may be involved in aggregation and cell-cell recognition.

Amino Acid Sequence↗
PubMed1977

Distribution of sulfated mucopolysaccharides in invertebrates.

The sulfated mucopolysaccharide composition of 22 species of invertebrates belonging to the phyla Arthropoda, Mollusca, Annelida, Tunicata, Echinodermata, Coelenterata, and Porifera was analyzed. It is shown that all the species contain variable amounts of one or more types of sulfated mocopolysaccharides, most of which similar to the ones found in vertebrates. It is shown also that each species has a characteristic composition, differing from each other regarding the relative amount and type of chondroitin sulfates A, B, and C, heparitin sulfate, and heparin. The possible biological role of the sulfated mucopolysaccharides in cell recognition or aggregation or both is discussed in view of the present findings.

Animals↗
PubMed1976

The activator of human cerebroside sulphatase. Activating effect on the acidic forms of the sulphatases from invertebrates.

1) Acidic forms of the sulphatase were partially purified from the following invertebrate species: Tethya aurantium (Porifera), Patella vulgata (mollusca), Maja squinado (Arthropoda), Marthasterias glacialis (Echinodermata) and Microcosmus sulcatus (Tunicata). Enzyme preparations thus obtained cleaved cerebroside sulphates (sulphatides) only in the presence of either specific detergents (e.g. taurodeoxycholate) or an activator protein isolated from human liver. This corresponds to the findings on purified sulphatase A of human origin. 2) At low concentrations, the activating effect was proportional to the amount of activator protein applied; at higher concentrations, proportionality was obtained only in some cases. On a molar basis, less of the activator protein was required to achieve the same activation as taurodeoxycholate. At optimum concentrations of the detergent however, the activation was much higher. 3) The enzyme specificity of the activator and some evolutionary implications are discussed.

Acetylglucosaminidase↗
PubMed1992

Secondary metabolites from marine organisms.

Marine macroorganisms and microorganisms, like terrestrial species, produce a dizzying array of secondary metabolites, including terpenes, steroids, polyketides, peptides, alkaloids and porphyrins. Most of the marine metabolites are found in terrestrial species as such or have close counterparts in land-based species, but some are sufficiently unusual to constitute a separate class (e.g. marine sterols). Although in many cases the functions of these secondary metabolites in the marine species themselves are unclear, other compounds play well-defined roles-for example as trail markers, sexual attractants, antifouling substances or antifeedants. What is clear is that many of the most interesting marine secondary metabolites have potent activities largely unrelated to their in situ roles. Examples abound of antitumour, antiviral, immunosuppressive and antimicrobial agents, as well as neurotoxins, hepatotoxins and cardiac stimulants. Relatively few biosynthetic studies of marine secondary metabolites have been done because of the logistical problems of working under water and the primitive state of techniques for growing marine invertebrates in culture. However, recent studies indicate that many compounds isolated from marine macrospecies (e.g. sponges) may instead be produced by microorganisms (e.g. bacteria or phytoplankton). Studies of these symbionts may facilitate efforts to understand the biosyntheses of these metabolites.

Amino Acid Sequence↗
PubMed1975

Feulgen microspectrophotometric analysis of deoxyribonucleoprotein organization in larval and adult freshwater sponge nuclei.

Microspectrophotometric measurements of nuclei of adult choanocytes and archeocytes and larval archeocytes and flagellated ectodermal epithelia from stages III and IV were undertaken on tissues from the freshwater sponge, Eunapius fragilis (Leidy). The condensed nuclei of differentiated choanocytes and state IV flagellated epithelial cells presented integrated extinction values about 64% of those obtained for either adult or larval archeocytes. This suggests that such measurements represent sensitive indicators of deoxyribonucleoprotein-complex organization; thus, nuclear differentiation. Further, no large population of G2 (4C) nuclei was found among these populations as has been reported in two classes of coelenterates.

Animals↗
PubMed1976

Sex reversal in a freshwater sponge.

Spongilla lacustris exhibits a type of alternative hermaphroditism, new to the phylum, in which a sponge may be exclusively male or female during the period of sexual reproduction one year and the opposite sex the next year. This form of sexuality may facilitate larva production and thus dispersal following colonization of a new habitat. Gametogenesis occurs shortly after gemmule hatching in both males and females but slightly later in males.

Animals↗