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PubMed1990

Seasonally occurring lectins from the bryozoan Bugula neritina.

Two different lectins (termed BnA-I and BnA-II) with distinct carbohydrate specificities were identified and subsequently isolated from the marine bryozoan Bugula neritina. BnA-I hemagglutinating activity was inhibited by N-acetylated hexosamines, their polymers, and glycoproteins rich in these moieties. BnA-II-induced hemagglutination was not blocked by any simple sugars but could be inhibited by several complex glycoproteins (e.g., thyroglobulin and orosomucoid). Both lectins required the presence of Ca(+)+ for reactivity and were purified by affinity chromatographic procedures. Purified BnA-I was determined to have a native molecular weight of 240 Kd and appeared to be a hexameric homopolymer while BnA-II was shown to be a 65-70 Kd monomer. Both lectins showed seasonality in expression, BnA-I appearing in animal extracts prepared in the spring and fall while BnA-II was expressed only during the summer and winter.

Animals↗
PubMed2004

Myo-anatomy of juvenile and adult loxosomatid Entoprocta and the use of muscular body plans for phylogenetic inferences.

The anatomy of the muscle bauplan in juvenile buds and adult specimens of the solitary loxosomatid entoprocts Loxosoma nielseni and L. annelidicola was studied by means of fluorescence staining of F-actin and confocal laser scanning microscopy. Although the general myo-anatomy of the body wall shows numerous similarities, both species express significant variations in the arrangement of their pedal muscles. In addition, L. annelidicola alone shows a distinct pair of rectum retractor muscles. Circular muscles are absent in the entire body wall of both species, as well as in previously investigated colonial taxa, which is therefore regarded as basal for Entoprocta. This is in striking contrast to the conditions found in other spiralian or lophotrochozoan taxa. The simple morphology of entoproct tentacle muscles, however, coincides with the phoronid-ectoproct condition and may be due to functional constraints of a simple filter-feeding system. This work shows that variations in the muscular anatomy provide useful characters for systematic analyses on species as well as phylum level and thus allow significant insight regarding metazoan body plan evolution. The phenomenon of phenotypic plasticity and its consequences for phylogenetic interpretations, however, must be carefully considered.

Actins↗
PubMed2006

Comparative anatomical study of internal brooding in three anascan bryozoans (Cheilostomata) and its taxonomic and evolutionary implications.

The anatomical structure of internal sacs for embryonic incubation was studied using SEM and light microscopy in three cheilostome bryozoans-Nematoflustra flagellata (Waters,1904), Gontarella sp., and Biflustra perfragilis MacGillivray, 1881. In all these species the brood sac is located in the distal half of the maternal (egg-producing) autozooid, being a conspicuous invagination of the body wall. It consists of the main chamber and a passage (neck) to the outside that opens independently of the introvert. There are several groups of muscles attached to the thin walls of the brood sac and possibly expanding it during oviposition and larval release. Polypide recycling begins after oviposition in Gontarella sp., and the new polypide bud is formed by the beginning of incubation. Similarly, polypides in brooding zooids degenerate in N. flagellata and, sometimes, in B. perfragilis. In the evolution of brood chambers in the Cheilostomata, such internal sacs for embryonic incubation are considered a final step, being the result of immersion of the brooding cavity into the maternal zooid and reduction of the protecting fold (ooecium). Possible reasons for this transformation are discussed, and the hypothesis of Santagata and Banta (Santagata and Banta1996) that internal brooding evolved prior to incubation in ovicells is rejected.

Animals↗
PubMed2006

Immunocytochemistry of the neuromuscular systems of Loxosomella vivipara and L. parguerensis (Entoprocta: Loxosomatidae).

Little detailed information exists on the anatomy of the nervous system and the musculature of Entoprocta. Herein we describe the distribution of the neurotransmitters RFamide and serotonin as well as the myo-anatomy of adults and asexually produced budding stages of the solitary entoproct species Loxosomella vivipara and L. parguerensis using immunocytochemistry and epifluorescence as well as confocal microscopy. The development of the RFamidergic and serotonergic nervous system starts in early budding stages. In the adults, RFamide is present in the bilateral symmetric cerebral ganglion, a pair of oral nerves that innervate two pairs of nerve cell clusters in the heel of the foot, a pair of aboral nerves, the paired lateral nerves, the calyx nerves, the atrial ring nerve, the tentacle nerves, the stomach nerves, and the rectal nerves. Serotonin is only found in the cerebral ganglion, the oral nerves, and in the tentacle nerves. Some differences in the distribution of both neurotransmitters were found between L. vivipara and L. parguerensis and are most obvious in the differing number of large serotonergic perikarya associated with the oral nerves. Nerves arising from the cerebral ganglion and running in a ventral direction have not been described for Entoprocta before, and the homology of these to the ventral nerve cords of other Spiralia is considered possible. The body musculature of both Loxosomella species comprises longitudinal and diagonal muscles in the foot, the stalk, and the calyx. We found several circular muscles in the calyx. The stalk and parts of the foot and the calyx are surrounded by a fine outer layer of ring muscles. In addition to the congruent details regarding the myo-anatomy of both species, species-specific muscle structures could be revealed. The comparison of our data with recent findings of the myo-anatomy of two Loxosoma species indicates that longitudinal and diagonal body muscles, atrial ring muscles, tentacle muscles, esophageal and rectal ring muscles, as well as intestinal and anal sphincters are probably part of the ancestral entoproct muscle bauplan.

Actins↗
PubMed2006

Defense of benthic invertebrates against surface colonization by larvae: a chemical arms race.

Sessile invertebrates evolved in a competitive milieu where space is a limiting resource, setting off an arms race between adults that must maintain clean surfaces and larvae that must locate and attach to a suitable substratum. I review the evidence that invertebrates chemically deter or kill the propagules of fouling animals and protists under natural conditions, and that chemosensory mechanisms may allow larvae to detect and avoid settling on chemically protected organisms. The fouling process is an ecologically complex web of interactions between basibionts, surface-colonizing microbes, and fouling larvae, all mediated by chemical signaling. Host-specific bacterial communities are maintained by many invertebrates, and may inhibit fouling by chemical deterrence of larvae, or by preventing biofilm formation by inductive strains. Larval settlement naturally occurs in a turbulent environment, yet the effects of waterborne versus surface-adsorbed chemical defenses have not been compared in flow, limiting our understanding of how larvae respond to toxic surfaces in the field. The importance of evaluating alternative hypotheses such as mechanical and physical defense is discussed, as is the need for ecologically relevant bioassays that quantify effects on larval behavior and identify compounds likely to play a defensive role in situ.

Animals↗
PubMed2006

5,6-Dichloro-1-methylgramine, a non-toxic antifoulant derived from a marine natural product.

The laboratory culture of the barnacle, Balanus amphitrite has made it possible to supply cypris larvae for antifouling assays all year round. The settlement of cyprids obtained from cultured B. amphitrite was indistinguishable from cyprids reared from field-collected barnacles. In laboratory cyprid settlement assays of extracts from marine sessile organisms, antifouling activity was expressed as the 99% inhibitory concentration (IC99), and toxicity as the 30% lethal concentration (LC30). The lipophilic extract of the marine bryozoan, Zoobotryon pellucidum, which showed promising antifouling activity, yielded 2,5,6-tribromo-1-methylgramine (TBG) by bioassay-guided isolation. The inhibitory activity of TBG was 6 times as strong as that of bis-(n-butyltin)oxide (TBTO), while its toxicity to cypris larvae was one-tenth that of TBTO. A structure-activity relationship study with 155 indole derivatives led to the discovery of the non-toxic antifoulant candidates 5,6-dichlorogramine, 5-chloro-2-methylgramine, and 5,6-dichrolo-1-methylgramine (DCMG), the latter being selected as the antifouling paint ingredient for performance evaluation tests (panel tests) following the results of a preliminary safety tests. A silicone-based antifouling paint containing 5-10% of DCMG was prepared and tested in the field; the painted surfaces remained almost barnacle-free for 1.5 years similar to silicone coatings such as Biox. Since the leaching rate of DCMG from the paint surface could be controlled by the addition of an acrylic acid-styrene copolymer (ASP), the life of the antifouling performance is expected to be improved. Thus, an extremely non-toxic silicone-based antifouling paint containing DCMG is under development.

Alkaloids↗
PubMed1977

Further observations of transport within paddle cilia.

Rhabdopleura has densely ciliated tentacles and cephalic shield. These cilia are of two sorts, ordinary cilia and those bearing paddle-like swellings. These swellings, about 1 micron across, are in the ciliary membrane. The axoneme bundle within the cilium remains intact, keeping the usual spatial arrangements, except that in the swelling its overall diameter is reduced. It is suggested that the mechanism for moving the paddle-like swellings along the length of the cilium is the releasing and reattaching of the side filaments from the axoneme to the ciliary membrane.

Animals↗
PubMed2002

Drugs from the seas - current status and microbiological implications.

The oceans are the source of a large group of structurally unique natural products that are mainly accumulated in invertebrates such as sponges, tunicates, bryozoans, and molluscs. Several of these compounds (especially the tunicate metabolite ET-743) show pronounced pharmacological activities and are interesting candidates for new drugs primarily in the area of cancer treatment. Other compounds are currently being developed as an analgesic (ziconotide from the mollusc Conus magus) or to treat inflammation. Numerous natural products from marine invertebrates show striking structural similarities to known metabolites of microbial origin, suggesting that microorganisms (bacteria, microalgae) are at least involved in their biosynthesis or are in fact the true sources of these respective metabolites. This assumption is corroborated by several studies on natural products from sponges that proved these compounds to be localized in symbiotic bacteria or cyanobacteria. Recently, molecular methods have successfully been applied to study the microbial diversity in marine sponges and to gain evidence for an involvement of bacteria in the biosynthesis of the bryostatins in the bryozoan Bugula neritina.

Animals↗
PubMed2003

Malacosporean-like spores in urine of rainbow trout react with antibody and DNA probes to Tetracapsuloides bryosalmonae.

Tetracapsuloides bryosalmonae is the myxozoan parasite causing proliferative kidney disease (PKD) of salmonid fishes in Europe and North America. The complete life cycle of the parasite remains unknown despite recent discoveries that the stages infectious for fish develop in freshwater bryozoans. During the course of examinations of the urine of rainbow trout (Oncorhynchus mykiss) with or recovering from PKD we identified spores with features similar to those of T. bryosalmonae found in the bryozoan host. Spores found in the urine were subspherical, with a width of 16 micro m and height of 14 microm, and possessed two soft valves surrounding two spherical polar capsules (2 microm in diameter) and a single sporoplasm. The absence of hardened valves is a distinguishing characteristic of the newly established class Malacosporea that includes T. bryosalmonae as found in the bryozoan host. The parasite in the urine of rainbow trout possessed only two polar capsules and two valve cells compared to the four polar capsules and four valves observed in the spherical spores of 19 microm in diameter from T. bryosalmonae from the bryozoan host. Despite morphological differences, a relationship between the spores in the urine of rainbow trout and T. bryosalmonae was demonstrated by binding of monoclonal and polyclonal antibodies and DNA probes specific to T. bryosalmonae.

Animals↗
PubMed2004

Links between the structure of an Antarctic shallow-water community and ice-scour frequency.

Ice is a major structuring force in marine and freshwater environments at high latitudes. Although recovery from scouring has been quantified in time, the frequency of scouring in the Antarctic has not. We placed grids of markers at 9-17 m depth at two sites, to study ice-scouring over 2 years at Adelaide island (Antarctic Peninsula). We quantified the time scale of scour frequencies, and linked this to community mortality, age and diversity. Markers were hit from zero to at least three times in 2 years. At the least disturbed site (South Cove) 24% of markers were destroyed per year, whereas in North Cove 60% of markers were destroyed. There were significant differences in scouring frequency between our two sites: a given area in North Cove was on average hit twice as often as one in South Cove. Compared with near shore environments elsewhere, faunas of both sites were characteristic of high disturbance regimes, exhibiting low percent cover, diversity, ages and a high proportion of pioneers. Aspects of the encrusting communities studied reflected the differences between site disturbance regimes. North Cove was scoured twice as often, and bryozoan communities there had half the number of species, two-thirds the space occupation and twice the mortality level of those in South Cove. Maximum age in North Cove bryozoans was also half that in South Cove. Although there are natural disturbance events that rival ice-scouring in either frequency or catastrophic power at lower latitudes, none do both nor across such a wide depth range. We suggest that ice scour effects on polar benthos are even more significant than the same magnitude of disturbance at lower latitudes as recovery rates of high latitude communities are very slow. Climate warming seems likely to increase iceloading of near shore polar waters, so that some of the world's most intensely disturbed faunas may soon suffer even more disturbance.

Analysis of Variance↗
PubMed1981

A clarification of the two types of invertebrate pleated septate junction.

It is confirmed that there are two distinct variations septate junction. The first of these, the 'lower invertebrate pleated septate junction', is described fully using conventional thin section, lanthanum tracer and freeze-fracture techniques. The second type, the well-known pleated septate junction characteristic of the molluscs and arthropods, is renamed the 'mollusc-arthropod pleated septate junction', and is described briefly to allow easier comparison between the two variations. As both types have not been studied in a range of invertebrate phyla the results can be used as a basis for discussing their respective phylogenetic positions. The lower invertebrate pleated septate junction occurs in several groups in the minor phyla immediately above the Coelenterata and in the lower phyla of both the deuterostome and proterostome lineages. The mollusc-arthropod pleated septate junction is restricted to the Mollusca and Arthropoda as its name implies.

Animals↗
PubMedDate not supplied

Bryostatins trigger human polymorphonuclear neutrophil and monocyte oxidative metabolism: association with in vitro antineoplastic activity.

Bryostatin-1-but not bryostatin-13-a macrocyclic lactone isolated from the marine bryozoan Bugula neritina, triggered human polymorphonuclear neutrophil (PMN) and monocyte release of reactive oxygen radicals, as measured by the generation of lucigenin chemiluminescence and by the ferricytochrome c reduction assay. The release of oxygen radicals by bryostatins was sensitive to inhibitors of protein kinases, but resistant to the inhibition of phospholipase A2 activity and arachidonic acid metabolism (prior treatment with mepacrine or indomethacin). Comparison of the effect of protein kinase (PK) inhibitors H-8, H-7 and staurosporine on bryostatin-1-induced neutrophil oxygen radical release further suggested a requirement for activation of phospholipid-dependent PKC, but not for cGMP- or cAMP-dependent PK. In cytostatic assays, PMNs treated with bryostatin-1 inhibited the growth of the erythroleukaemic cell line K562 in a concentration-dependent manner. These findings suggest that the reported antineoplastic effect of bryostatins may result at least in part from activation of PMNs and monocytes.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed2004

bryA: an unusual modular polyketide synthase gene from the uncultivated bacterial symbiont of the marine bryozoan Bugula neritina.

"Candidatus Endobugula sertula," the uncultivated bacterial symbiont of Bugula neritina, is the proposed source of the bryostatin family of anticancer compounds. We cloned a large modular polyketide synthase (PKS) gene complex from "Candidatus Endobugula sertula" and characterized one gene, bryA, which we propose is responsible for the initial steps of bryostatin biosynthesis. Typical PKS domains are present. However, acyltransferase domains are lacking in bryA, and beta-ketoacyl synthase domains of bryA cluster with those of PKSs with discrete, rather than integral, acyltransferases. We propose a model for biosynthesis of the bryostatin D-lactate starter unit by the bryA loading module, utilizing atypical domains homologous to FkbH, KR, and DH. The bryA gene product is proposed to synthesize a portion of the pharmacologically active part of bryostatin and may be useful in semisynthesis of clinically useful bryostatin analogs.

Amino Acid Sequence↗
PubMed2006

Heavy metal contamination and antioxidant response of a freshwater bryozoan (Lophopus crystallinus Pall., Phylactolaemata).

Monthly variations of total glutathione, glutathione-S-transferases, glutathione peroxidase, glutathione reductase, glyoxalase I, glyoxalase II, and catalase were studied in Lophopus crystallinus, a freshwater bryozoan, collected from Lake Piediluco. Specimens were sampled during the vegetative period from November to April for two different cycles: cycle I from 1996 to 1997 and cycle II from 1999 to 2000. Simultaneously, analyses of heavy metal content such as lead, cadmium, chromium, nickel, copper, iron, and zinc were determined in the samples of L. crystallinus. Specimens of cycle II displayed highest chromium and iron accumulation and elevated levels of biochemical parameters. Total glutathione content, catalase, and glutathione peroxidase activities, were related with the highest metal concentrations in L. crystallinus from Lake Piediluco.

Animals↗