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PubMed2006

Impact of environmental conditions on the marine natural product bryostatin 1.

Marine Natural Products (MNPs), such as bryostatin 1, are exposed to a range of physical and chemical conditions through the life cycle of the host organism. These include exposure to sunlight, oxidizing and reducing agents, cation binding, and adsorption to reactive metal oxide surfaces. Using Fourier Transform-Ion Cyclotron Resonance (FT-ICR), Matrix Assisted Laser Desorption Ionization Mass Spectrometry (MALDI-MS), UV/Vis absorbance spectroscopy, and molecular modeling, we studied the impact of UV light, TiO2, I2, and reaction with FeCl3 on the structure of bryostatin 1. Our results demonstrate that natural conditions transform bryostatin to a number of structures, including one with a molar mass of 806 Da, which we have previously identified in the sediment collected from the Gulf of Mexico. To date, at least 20 different structures of bryostatin have been reported in the literature. This work suggests that these variations may be products of the chemical environment in which the bryozoa Bugula neritina resides and are not the result of genetic variations within Bugula.

Animals↗
PubMed2000

Water-borne sperm trigger vitellogenic egg growth in two sessile marine invertebrates.

A diverse array of sessile marine invertebrates mate by passive dispersal of sperm which fertilize the brooded eggs of neighbours. In two such species, a sea-mat (phylum Bryozoa) and an ascidian (phylum Chordata), vitellogenic egg growth is absent in reproductively isolated specimens, but is triggered by a water-borne factor released by conspecifics. In both of these colonial, hermaphroditic species, the active factor can be removed from water by filtration. The effect involves self-/non-self-recognition: water conditioned by a separate subcolony of the same genetic individual does not prompt oocyte growth. In each species, allosperm move from the surrounding water to the ovary and are then stored in close association with the growing oocytes. We concluded that sperm themselves are the water-borne factor that triggers the major phase of female reproductive investment. This mechanism is, to our knowledge, previously undescribed in animals, but has parallels with the initiation of maternal investment in flowering plants following the receipt of compatible pollen. The species studied may be representative of many other aquatic invertebrates which mate in a similar way. The stimulation of egg growth by allosperm could lead to intersexual conflict during oogenesis.

Animals↗
PubMed1999

The rational design of potential chemotherapeutic agents: synthesis of bryostatin analogues.

The bryostatins are a unique family of cancer chemotherapeutic candidates isolated from marine bryozoa. While their molecular mode of action is not known, these macrolactones exhibit high affinities for protein kinase C (PKC) isozymes, compete for the phorbol ester binding site on PKC, and stimulate kinase activity in vitro and in vivo. Unlike the phorbol esters, they do not act as tumor promoters. Despite promising biological properties, the supply of these compounds is limited by the difficulty of their isolation from natural sources and their synthetic complexity. A new class of bryostatin analogues which retain the putative recognition domain of the bryostatins but are simplified through deletions and modifications in the C1-C14 spacer domain have been designed using computer models. A convergent synthesis has been realized for the production, in gram quantities, of these recognition and spacer domains whose coupling allows for the generation of a range of analogues. The final closure process involves a novel macrotransacetalization reaction which proceeds with complete stereoselectivity. The solution structures of two synthetic analogues were determined by NMR spectroscopy and found to be very similar to the previously reported structures of bryostatins 1 and 10. In addition, these structures appear to indicate that the stereochemistry of the C3 hydroxyl group plays a significant role in the conformation of the macrolactone. All analogues bound strongly to a mixture of PKC isozymes, and several exhibited significant levels of in vitro growth inhibitory activity against human cancer cell lines. Taken together, this work provides important steps toward the development and understanding of simplified, synthetically accessible analogues of the bryostatins as potential chemotherapeutic agents.

Adjuvants, Immunologic↗
PubMed2006

Lophotrochozoan phylogeny assessed with LSU and SSU data: evidence of lophophorate polyphyly.

Of the three major bilaterian clades, Lophotrochozoa has the greatest diversity and disparity of body forms and is the least understood in terms of phylogenetic history. Within this clade, small nuclear ribosomal subunit (SSU or 18S) studies have failed to provide resolution and other molecular markers have insufficient taxon sampling. To examine relationships within Lophotrochozoa, we collected and complied complete SSU data and nearly complete (>90%) large nuclear ribosomal subunit (LSU or 28S) data totaling approximately 5kb per taxon, for 36 lophotrochozoans. Results of LSU and combined SSU+LSU likelihood analyses provide topologies more consistent with morphological data than analyses of SSU data alone. Namely, most phyla recognized on morphological grounds are recovered as monophyletic entities when the LSU data is considered (contra SSU data alone). These new data show with significant support that "Lophophorata" (traditionally recognized to include Brachiopoda, Phoronida, and Bryozoa) is not a monophyletic entity. Further, the data suggest that Platyzoa is real and may be derived within lophotrochozans rather than a basal or sister taxon. The recently discovered Cycliophora are allied to entoprocts, consistent with their initial placement based on morphology. Additional evidence for Syndermata (i.e., Rotifera+Acanthocephala) is also found. Although relationships among groups with trochophore-like larvae could not be resolved and nodal support values are generally low, the addition of LSU data is a considerable advance in our understanding of lophotrochozoan phylogeny from the molecular perspective.

Animals↗
PubMed2005

Ultrastructural and molecular characterization of Bacillidium vesiculoformis n. sp. (Microspora: Mrazekiidae) in the freshwater oligochaete Nais simplex (Oligochaeta: Naididae).

The development of a new species, Bacillidium vesiculoformis n. sp. (Microspora, Mrazekiidae), is described from the freshwater oligochaete Nais simplex (Oligochaeta, Naididae). Initial stages of parasite development consist of a monokaryotic merogony within a haemocyte of the intestinal blood sinus. The resulting hypertrophied haemocyte is attached to the chloragocytes of the sinus by fine cytoplasmic extensions with the sinus around the cell becoming greatly enlarged. The meronts within the haemocyte form diplokaryotic sporonts that undergo sporogenesis directly within the cytoplasm of the host cell. The infected cell becomes packed with spores and developmental stages, causing it dramatically to increase in size, eventually rupturing the oligochaete and cell. Sporogony appears to be disporoblastic. Released spores were observed to have an adhesive quality. Transmission studies conducted with mature spores failed to transmit the parasite horizontally although vertical transmission was observed. Phylogenetic analysis of the parasite demonstrated that B. vesiculoformis clustered with microsporidian parasites of bryozoa and two other microsporidians, Janacekia debaiseuxi and an unidentified Bacillidium sp.

Animals↗
PubMed1990

Inducible morphology, heterochrony, and size hierarchies in a colonial invertebrate monoculture.

Conditional or inducible strategies are a powerful tool for analyzing the evolution of aggressive behavior. Structures such as stolons and nematocyst-laden tentacles, induced to deter encroachment by competitors, are proportionately better represented in clonal and colonial marine invertebrates than in aclonal animals. Stolons can be produced by colonies of Membranipora membranacea (Bryozoa) within 48 hr after contact with conspecifics. Absolute size and relative size of interacting colonies determine whether stolons will be produced. Although individual stolons are eventually overgrown by conspecifics, they reduce the size of affected zooids by 27%. Since stolon production is primarily a strategy of large colonies, we suggest that stolons function to limit space occupied by small colonies and may also trigger early and localized reproduction. Thus large colonies can surround multiple small mates and, because they reproduce only locally where induced by contact with small colonies, still maintain high growth rates on free colony perimeters. Stolons appear to be juvenilized zooids and to originate through a process of heterochrony. These induced facultative polymorphisms may be one pathway by which fixed polymorphisms arise in colonial invertebrates. We attribute the unique production of inducible structures against competitors by clonal and colonial invertebrates to both unusually high levels of development plasticity and an energetically favorable architecture for perimeter defense.

Journal Article↗
PubMed1998

The design, computer modeling, solution structure, and biological evaluation of synthetic analogs of bryostatin 1.

The bryostatins are a unique family of emerging cancer chemotherapeutic candidates isolated from marine bryozoa. Although the biochemical basis for their therapeutic activity is not known, these macrolactones exhibit high affinities for protein kinase C (PKC) isozymes, compete for the phorbol ester binding site on PKC, and stimulate kinase activity in vitro and in vivo. Unlike the phorbol esters, they are not first-stage tumor promoters. The design, computer modeling, NMR solution structure, PKC binding, and functional assays of a unique class of synthetic bryostatin analogs are described. These analogs (7b, 7c, and 8) retain the putative recognition domain of the bryostatins but are simplified through deletions and modifications in the C4-C14 spacer domain. Computer modeling of an analog prototype (7a) indicates that it exists preferentially in two distinct conformational classes, one in close agreement with the crystal structure of bryostatin 1. The solution structure of synthetic analog 7c was determined by NMR spectroscopy and found to be very similar to the previously reported structures of bryostatins 1 and 10. Analogs 7b, 7c, and 8 bound strongly to PKC isozymes with Ki = 297, 3.4, and 8.3 nM, respectively. Control 7d, like the corresponding bryostatin derivative, exhibited weak PKC affinity, as did the derivative, 9, lacking the spacer domain. Like bryostatin, acetal 7c exhibited significant levels of in vitro growth inhibitory activity (1.8-170 ng/ml) against several human cancer cell lines, providing an important step toward the development of simplified, synthetically accessible analogs of the bryostatins.

Animals↗
PubMed2000

Triploblastic relationships with emphasis on the acoelomates and the position of Gnathostomulida, Cycliophora, Plathelminthes, and Chaetognatha: a combined approach of 18S rDNA sequences and morphology.

Triploblastic relationships were examined in the light of molecular and morphological evidence. Representatives for all triploblastic "phyla" (except Loricifera) were represented by both sources of phylogenetic data. The 18S ribosomal (rDNA) sequence data for 145 terminal taxa and 276 morphological characters coded for 36 supraspecific taxa were combined in a total evidence regime to determine the most consistent picture of triploblastic relationships for these data. Only triploblastic taxa are used to avoid rooting with distant outgroups, which seems to happen because of the extreme distance that separates diploblastic from triploblastic taxa according to the 18S rDNA data. Multiple phylogenetic analyses performed with variable analysis parameters yield largely inconsistent results for certain groups such as Chaetognatha, Acoela, and Nemertodermatida. A normalized incongruence length metric is used to assay the relative merit of the multiple analyses. The combined analysis having the least character incongruence yields the following scheme of relationships of four main clades: (1) Deuterostomia [((Echinodermata + Enteropneusta) (Cephalochordata (Urochordata + Vertebrata)))]; (2) Ecdysozoa [(((Priapulida + Kinorhyncha) (Nematoda + Nematomorpha)) ((Onychophora + Tardigrada) Arthropoda))]; (3) Trochozoa [((Phoronida + Brachiopoda) (Entoprocta (Nemertea (Sipuncula (Mollusca (Pogonophora (Echiura + Annelida)))))))]; and (4) Platyzoa [((Gnathostomulida (Cycliophora + Syndermata)) (Gastrotricha + Plathelminthes))]. Chaetognatha, Nemertodermatida, and Bryozoa cannot be assigned to any one of these four groups. For the first time, a data analysis recognizes a clade of acoelomates, the Platyzoa (sensu Cavalier-Smith, Biol. Rev. 73:203-266, 1998). Other relationships that corroborate some morphological analyses are the existence of a clade that groups Gnathostomulida + Syndermata (= Gnathifera), which is expanded to include the enigmatic phylum Cycliophora, as sister group to Syndermata.

Animals↗
PubMed1991

Distinct modulatory effects of bryostatin 1 and staurosporine on the biosynthesis and expression of the HIV receptor protein (CD4) by T cells.

A family of structurally related macrocyclic lactones, bryostatins, have recently been shown to display several intriguing pharmacologic properties. Bryostatins are biosynthetic products of bryozoa phyllum of marine animals. To extend the analyses of the biological activities of these highly unusual biosynthetic animal products, we have examined the effect of bryostatin 1 (bryo-1) on the steady-state expression of the human immunodeficiency virus receptor, CD4, by normal peripheral blood T lymphocytes. Incubation of the cells with 5 nM bryo-1 caused a substantial loss of CD4 from the cell surface, as analyzed by flow cytometry using anti-CD4 monoclonal antibody. The modulation of CD4 expression by bryo-1 was not due to a cytotoxicity effect: in the culture conditions where it modulated CD4, bryo-1 also stimulated the expression of the interleukin 2 gene, as indicated by northern blot hybridization. In addition, incubation of the lymphocytes with nanomolar amounts of protein kinase C antagonist, staurosporine, resulted in the inhibition of the bryo-1-induced modulation of CD4 expression. The results of radioimmunoprecipitation analysis of detergent lysates of [35S] methionine-labeled lymphocytes strongly suggest that bryo-1 inhibits the glycosylation and expression of CD4 in a manner similar to that of tunicamycin.

Adjuvants, Immunologic↗
PubMed2000

[Distribution and origin of plastic resin pellets as environmental pollutants at the East China Sea area].

Plastic debris are important marine pollutants. Plastic debris consist of resin pellets and waste plastics. We are particularly interested in resin pellets. We made field survey of resin pellets at nearly 400 sites in 200 beaches in Japan and neighboring countries. The pellets were found at all most all Japan coasts we surveyed and at some beaches of Macao, Hong Kong, Xiamen, the north of Taipei, and Cheju Island in Korea. The number of pellets was more than 1000 pieces per m2 on the most abundant beach in Japan. Through further analysis using GC/ECD, endocrine disrupting chemicals, PCBs, DDTs, HCHs and Nonylphenol were detected in selected samples. Biota such as Bryozoa were observed on the surface of pellets washed up on the beaches in subtropical areas. Pellets has been suspected to affect wildlife and human health, but we have no report on affection to human.

Animals↗
PubMed2005

Aquaculture of "non-food organisms" for natural substance production.

Marine invertebrates are already sources of commercially important secondary metabolites and may become even more so as knowledge on marine natural products and chemical ecology develops. Among the producers of these compounds predominantly sponges, bryozoa and molluscs have received the attention of academic and industrial research and development. For all these invertebrate groups culture techniques have been developed encompassing in situ, laboratory and cell culture approaches for the production of natural products. Potential applications of these are not restricted to pharmaceuticals but include marine cements, biominerals and antifouling compounds. In addition, markets exist for ornamental species. All culture approaches require sound ecological knowledge about the organisms to be cultured and possible symbiotic interactions between host invertebrates and microheterotrophs.

Animals↗
PubMedDate not supplied

[The shell of invertebrate and plant propagules: selective permeability and barriers].

In the experiments with seeds of Ericaceae, gemmuls of Spongia, statoblasts of Bryozoa, resting eggs and ephippia of Crustacea the hypothesis on selective permeability of propagule shells was tested. It was shown that the propagules are activated and develop until the moment of destruction of shell in the solutions of phenols, formaldehyde, CuSO4, K2Cr2O7, HgCl2, Ag2SO4, AgNO3, CoCl2 and NiSO4. It means that propagule shell is impermeable for these poisons but permeable for water and oxygen. The effectiveness of barrier can be various in different species but in some cases it is very high. The development of resistance to poisons of anthropogenic origin that were not familiar to organism earlier can be considered as an example of the rule (Rasnitzyn, 1971) according which relation between environmental variability and power of regulator is shifted to the priority of regulator. Selectively permeable shell for many organisms is a common adaptation that allows colonization of land and continental waters.

Adaptation, Physiological↗
PubMed1990

[Anti-tumor marine natural products].

In anticipation of developing new anti-cancer drugs from marine organisms of rich species, a variety of anti-tumor substances having diverse chemical structures have been discovered. Among those marine anti-tumor substances, which were reviewed in a previous paper [Jpn. J. Cancer Chemother., 16, 1-8 (1989)], several compounds promising as anti-cancer drugs are detailed in this article. They are didemnin B from marine tunicate, bryostatin 1 from marine bryozoa, and dolastatin 10 from sea hare. In addition, several anti-tumor marine sponge constituents: halichondrin B, calyculin A, and mycalamides A and B, are briefly reviewed.

Animals↗
PubMed1988

Diagnostic positive and negative ion fast atom bombardment mass spectrometry of low-molecular-weight ammonium compounds of marine origin.

Five ammonium compounds--betaine, taurine, homarine, trigonelline and tetramethylammonium chloride--were investigated by positive and negative ion fast atom bombardment (FAB) mass spectrometry. Observation of the parent cation [M + H]+ together with series of clusters (e.g. [nM + H]+, n = 2-5) and fragmentation patterns in the positive FAB mode may be used diagnostically as a fingerprint of the compound. The shifts in mass and relative intensity by addition of trichloroacetic acid and metal salts offer corroborating information of the identity of a compound in a mixture. The FAB negative ion spectra were characterized by clusters incorporating the anion (e.g. [M + Cl]-) but are generally less informative than the spectra obtained in the positive mode.

Alkaloids↗
PubMed2006

Natural products from marine organisms and their associated microbes.

The marine environment is distinguished by unique groups of organisms being the source of a wide array of fascinating structures. The enormous biodiversity of marine habitats is mirrored by the molecular diversity of secondary metabolites found in marine animals, plants and microbes. The recognition that many marine invertebrates contain endo- and epibiotic microorganisms and that some invertebrate-derived natural products are structurally related to bacterial metabolites suggests a microbial origin for some of these compounds. Other marine natural products, however, are clearly located in invertebrate tissue and microbial involvement in the biosynthetic process seems unlikely. The complexity of associations in marine organisms, especially in sponges, bryozoans and tunicates, makes it extremely difficult to definitively state the biosynthetic source of many marine natural products or to deduce their ecological significance. Whereas many symbiotic marine microorganisms cannot be isolated and cultured, numerous epi- and endobiotic marine fungi produce novel secondary metabolites in laboratory cultures. The potent biological activity of many marine natural products is of relevance for their ecological function but is also the basis of their biomedical importance.

Animals↗