Anatomy of the larva of Amathia vidovici (Bryozoa: Ctenostomata) and phylogenetic significance of the vesiculariform larva

Amathia vidovici (Vesiculariidae) has a lecithotrophic coronate larva. The apical disc of A. vidovici larvae is more complex than that of other vesiculariids and includes a new cell type, which may be glial-like in function. A massive nerve nodule consists only of neural processes; as no ganglia or other evidence of interneurons were found, sensory cells apparently innervate their effectors directly. Putative synaptic junctions within the nerve nodule indicate that both receptor and effector cells send processes to this neuropile. Some 44 intercoronal cells of three types, two of which are new, are interspersed among the approximately 40 coronal cells. Juxtapapillary bodies, a unique sensory complex previously known only from Bowerbankia gracilis larvae, also occur in A. vidovici. A large refractile body, which is of uncertain function and is positioned near the center of the larva, is described for the first time. A comparison of vesiculariid larvae that have been studied at the ultrastructural level reveals that larvae of Amathia vidovici and Bowerbankia gracilis are more similar to each other than either is to B. imbricata. Differences between the two Bowerbankia species, however, may reflect relative detail of their study and differences in interpretation rather than intergenic plasticity. Nevertheless. a distinctive suite of larval characteristics are shared by other members of the family Vesiculariidae, justifying a specific name—vesiculariform—for their larvae. A number of the defining characteristics of vesiculariform larvae also appear in the carnosan superfamily Victorelloidae. This finding is consistent with arguments based on adult characteristics that the Victorelloidea are ancestral to the Vesicularioidea. If this geneology is correct, one can predict that those vesiculariform traits which originated in the victorellids are plesiomorphic not only to the Family Vesiculariidae but to all sister taxa placed in the Vesicularioidea. © 1993 Wiley-Liss, Inc.     

The Occurrence of Bulbella abscondita (Bryozoa,Ctenostomata) in Brackish Waters of Northern Italy

The victorellid bryozoans, Tanganella muelleri and Bulbella abscondita, have been found in the delta of the River Po, Northern Italy. Our finds seem to be the first recorded of B. abscondita in waters in Italy.     

The ontogenetical and supposed phylogenetical fate of the parietal muscles in the Ctenostomata (Bryozoa)

A new term, “trophon”, has been introduced for the feeding and sexually propagating unit in the stolonate ctenostomes; the “stolon” and the “trophon” represent “sukzooids”, because they are homologous only to parts of the autozooids in the uniserially arranged ctenostomes. – The ontogeny of the muscles, especially the parietal muscles, has been studied in 17 species of ctenostomatous bryozoans belonging to different sub-groups of this order; the main effort was directed toward the details of the differentiations in living animals (14 of the investigated species). In various species of the Ctenostomata two separate sets of parietal muscles develop – probably as a consequence of the elongation of the cystid; the functional parietal muscles in the trophons of the stolonial forms are homologous to the secondary parietal muscles found in several uniserial ctenostomes. Contrary to the supposition by Soule (1954) in the different families of the serially arranged forms the muscles appear in different sequences during the development of the zooid and partly have different ontogenetical fates. Neither the “Carnosa” nor the “Paludicellea” (s. 1.) nor the “Stolonifera” can be maintained as taxa with the argument of a similar ontogeny of the muscles. A detailed comparison regarding the fate of the parietal muscles (and the polypide anlage) showed similarities between certain of the uniserial to either some of the stolonial, the sheet like, or the cystid-fusing forms suggesting a separate evolutionary origin of the advanced forms in those groups of the serially growing forms. – A new family, Pottsiellidae fam. nov., has been introduced and defined.     

Theoretical morphology of colonial meshworks in the Fenestrata (Bryozoa): modelling hydraulic-resistance constraints and minimum fenestrule widths

Ancient fenestrate bryozoans (Fenestellidae, Polyporidae) exhibit a range of fenestrule widths that can be investigated to gain insights about constraints on meshwork morphology. Theoretical morphospace analyses of branch width and spacing reveal that there is a minimum fenestrule width common to both groups. We propose that the minimum fenestrule width observed in fenestrate colonies was constrained by hydraulic resistance (the hydraulic-resistance-constraint hypothesis). Modelling that considers both the viscous and inertial components of fluid-flow resistance through hypothetical fenestrate meshworks corroborates this hypothesis for the smaller fenestrate meshworks of the biserial fenestellids and for polyporids with branch widths less than about 0.6 mm. However, the geometry of the polyporid meshworks in species with branches wider than 0.6 mm does not appear to have been determined by a hydraulic-resistance constraint. Instead, maximum branch densities in the larger-branched polyserial polyporid colonies appear to have been constrained by a limit on the number of zooid rows that these colonies could develop on their branches (the zooid-row-limit hypothesis). The observed decrease in the minimum fenestrule width in these colonies is the indirect geometric result of the inability of the larger polyserial polyporid colonies to develop meshworks with high branch densities.     

Metal and antibiotic resistance in psychrotrophic bacteria associated with the Antarctic sponge Hemigellius pilosus (Kirkpatrick, 1907)

High concentrations of heavy metals have been previously detected in Antarctic sponge tissues, but their effect on the associated bacterial assemblages has been never investigated. Metal tolerance is often linked to antibiotic resistance and can also affect biochemical activities within microbial populations. In the present work, the response to heavy metals and antibiotics, as well as the enzymatic profile, of bacteria associated with the sponge Hemigellius pilosus, was analyzed. Tolerance to mercury, cadmium and zinc (at concentrations between 10 and 10,000 ppm) was tested by the plate diffusion method. Almost all isolates completely tolerated zinc and cadmium up to 1,000 and 2,500 ppm, respectively, whereas complete tolerance to mercury was generally observed at concentrations between 10 and 500 ppm. As bacteria can develop resistance in the growing presence of toxic compounds in the environment, this finding could be related to the concentrations of metals in the sponge tissues. The susceptibility assay to 11 antibiotics revealed that multiple antibiotic resistance was generally exhibited, with gentamicin that inhibited all Antarctic isolates. The comparison of the heavy metal and antibiotic resistance patterns at phylogenetic level revealed some distinctive features, suggesting that the dissemination of heavy metal tolerance and antibiotic resistance may possess great relevance for the population dynamics. Additionally, growth patterns often highly differed among strains in the same species, thus appearing to be more likely strain specific rather than species specific. The enzyme expression by the isolates was not really affected by the heavy metal tolerance they showed, as variation in the enzymatic profiles was observed in strains within the same genus that showed different/similar heavy metal tolerance patterns.     

Pyrrolizidine alkaloids in and on the leaf surface of Senecio jacobaea L

This is the first study showing that alkaloids are present on the leaf surface of plants. A concentration of 30-230 pmol/cm2 pyrrolizidine alkaloids (PA's) was detected in 8 different samples taken from Senecio jacobaea. PA concentration on the leaves was marginally correlated with PA concentration of the total leaf tissues. The PA spectrum on the leaf differed from the PA spectrum of the total leaf.     

Iron bacteria in Devonian carbonates (Tafilalt, Anti-Atlas, Morocco)

A condensed Mid-Upper Devonian succession of the Tafilalt (Anti-Atlas) contains numerous red carbonate intervals. Bioclastic tempestites form a transition between an outer shelf and a hemipelagic setting. The red pigmentation is not related to the abundance of detrital iron oxides, but to the presence of iron bacteria and fungi. They form bioconstructions remarkably similar to those previously described in the Jurassic Ammonitico Rosso from Italy and Spain. Thus, dysaerobic microenvironments are proposed and not oxic conditions for these Fe-poor sediments.     

Immunolocalization of the Toxin Latrunculin B within the Red Sea Sponge Negombata magnifica (Demospongiae, Latrunculiidae)

The location of latrunculin B, the major toxin of the Red Sea sponge Negombata magnifica, was revealed using specific antibodies. Antibodies from rabbits immunized with a conjugate of latrunculin B with keyhole limpet hemocyanin (KLH) were purified over a latrunculin B–Sepharose affinity column. Analysis of immunohistochemical and immunogold-stained sponge sections, using light and transmission electron microscopy, revealed latrunculin B labeling mostly beneath the sponge cortex at the border between the external (ectosome) and internal (endosome) layers (ectosome-endosome border). The endosome was less labeled than the border. Immunogold localization revealed latrunculin B in the sponge cells but not in its prokaryotic symbionts. Archeocytes and choanocytes were significantly more labeled than other cells. The antibodies primarily labeled membrane-limited vacuoles within archeocytes and choanocytes that are perhaps latrunculin B secretory or storage vesicles. Peripheral latrunculin B may have a role in defense against external epibionts, predators, and competitors. Received December 21, 1999; accepted March 5, 2000.     

Physiology, phylogenetic relationships, and ecology of filamentous sulfate-reducing bacteria (genus Desulfonema)

Microscopy of organic-rich, sulfidic sediment samples of marine and freshwater origin revealed filamentous, multicellular microorganisms with gliding motility. Many of these neither contained sulfur droplets such as the Beggiatoa species nor exhibited the autofluorescence of the chlorophyll-containing cyanobacteria. A frequently observed morphological type of filamentous microorganism was enriched under anoxic conditions in the dark with isobutyrate plus sulfate. Two strains of filamentous, gliding sulfate-reducing bacteria, Tokyo 01 and Jade 02, were isolated in pure cultures. Both isolates oxidized acetate and other aliphatic acids. Enzyme assays indicated that the terminal oxidation occurs via the anaerobic C₁ pathway (carbon monoxide dehydrogenase pathway). The 16S rRNA genes of the new isolates and of the two formerly described filamentous species of sulfate-reducing bacteria, Desulfonema limicola and Desulfonema magnum, were analyzed. All four strains were closely related to each other and affiliated with the δ-subclass of Proteobacteria. Another close relative was the unicellular Desulfococcus multivorans. Based on phylogenetic relationships and physiological properties, Strains Tokyo 01 and Jade 02 are assigned to a new species, Desulfonema ishimotoi. A new, fluorescently labeled oligonucleotide probe targeted against 16S rRNA was designed so that that it hybridized specifically with whole cells of Desulfonema species. Filamentous bacteria that hybridized with the same probe were detected in sediment samples and in association with the filamentous sulfur-oxidizing bacterium Thioploca in its natural habitat. We conclude that Desulfonema species constitute an ecologically significant fraction of the sulfate-reducing bacteria in organic-rich sediments and microbial mats. Received: 30 December 1998 / Accepted: 19 July 1999     

Ingestion of bacteria in suspension Indian major carps (Catla catla,Labeo rohita) and Chinese carps (Hypophthalmichthys molitrix,Aristichthys nobilis)

Single-species groups of fry of the planktivorous, filter-feeding carps (silver carp Hypophthalmichthys molitrix, bighead carp Aristichthys nobilis, rohu Labeo rohita and catla Catla catla) were exposed to the bacterium Chromobacterium violaceum to assess if they could detect or ingest unattached bacteria. The results indicate that planktivorous carp fry are able to ingest unattached bacteria and that the numbers ingested increase with time and with bacterial concentration in the media, although probably by passive means. It is also suggested that unattached bacteria are of little nutritional significance to carps.     

Isolation,characterization and pathogenicity of bacteria from Rhynchites bacchus (Coleoptera: Rhynchitidae)

The leafroller weevil beetle (Rhynchites bacchus L., Coleoptera: Rhynchitidae) is one of the most serious pests of apple, plum, apricot, cherry and peach (nectarine) fruit worldwide. The aim of this study was to isolate and characterize pathogenic bacteria from this pest for possible use in biocontrol, and to determine their pathogenicity. R. bacchus were collected from the Eastern Black Sea Region of Turkey in 2007. Based on their morphological, physiological and biochemical features, five different bacterial isolates were obtained from adults and larvae. In addition, 16S rRNA gene was amplified and sequenced to confirm isolate identification. According to the numerical and molecular data, the culturable bacterial flora of R. bacchus was determined as Bacillus licheniformis (Rb1), Serratia marcescens (Rb2), Enterobacter hormaechei (Rb3), Paenibacillus sp. (Rb4), and Enterobacter sp. (Rb5). Isolate Rb2 produced the highest mortality (73%) against larvae within 10 days after inoculation (P<0.05). The others, Rb1, Rb3, Rb4 and Rb5, caused 20, 13, 26 and 13% mortality in the larvae within the same period. These results indicate that S. marcescens Rb2 seems to be the most promising biocontrol agent againts this pest.     

Tissue distribution and biosynthesis of 1,2-saturated pyrrolizidine alkaloids in Phalaenopsis hybrids (Orchidaceae)

Phalaenopsis hybrids contain two 1,2-saturated pyrrolizidine monoesters, T-phalaenopsine (necine base trachelanthamidine) and its stereoisomer Is-phalaenopsine (necine base isoretronecanol). T-Phalaenopsine is the major alkaloid accounting for more than 90% of total alkaloid. About equal amounts of alkaloid were genuinely present as free base and its N-oxide. The structures were confirmed by GC-MS. The quantitative distribution of phalaenopsine in various organs and tissues of vegetative rosette plants and flowering plants revealed alkaloid in all tissues. The highest concentrations were found in young and developing tissues (e.g., root tips and young leaves), peripheral tissues (e.g., of flower stalks) and reproductive organs (flower buds and flowers). Within flowers, parts that usually attract insect visitors (e.g., labellum with colorful crests as well as column and pollinia) show the highest alkaloid levels. Tracer feeding experiments with (14)C-labeled putrecine revealed that in rosette plants the aerial roots were the sites of phalaenopsine biosynthesis. However active biosynthesis was only observed in roots still attached to the plant but not in excised roots. There is a slow but substantial translocation of newly synthesized alkaloid from the roots to other plant organs. A long-term tracer experiment revealed that phalaenopsine shows neither turnover nor degradation. The results are discussed in the context of a polyphyletic molecular origin of the biosynthetic pathways of pyrrolizidine alkaloids in various scattered angiosperm taxa. The ecological role of the so called non-toxic 1,2-saturated pyrrolizidine alkaloids is discussed in comparison to the pro-toxic 1,2-unsaturated pyrrolizidine alkaloids. Evidence from the plant-insect interphase is presented indicating a substantial role of the 1,2-saturated alkaloids in plant and insect defense.     

The effects of ambient flow velocity,colony size,and upstream colonies on the feeding success of Bryozoa. II. Conopeum reticulum (Linnaeus), an encrusting species

The effects of ambient flow velocity, colony size, and the presence of an actively-feeding colony upstream on the feeding success of the encrusting bryozoan Conopeum reticulum (Linnaeus) were studied. Zooids from both large and small colonies showed a reduction in feeding as flow velocity increased, however, the reduction in feeding was less for zooids from large colonies except at very fast ambient flow velocities. The greater pumping capacity of large colonies may result in a relatively greater per zooid feeding success from moving water. The presence of an actively-feeding colony upstream was found to enhance the feeding of zooids on downstream colonies. Diversion of flowing water by actively-feeding colonies upstream may account for the observed enhancement of feeding by zooids on colonies downstream.The results from this study on an encrusting species are compared with results from a previous study on feeding from flow by an arborescent bryozoan, and the feeding performances of these two colony types are related to their respective flow microhabitats.     

Redescription of Alcyonidium my till Dalyell, 1848 (Bryozoa: Gtenostomatida)

Reproduction in the ctenostomate bryozoan Alcyonidium mytili Dalyell, 1848, was studied over 2 years, revealing confusion in the literature over the diagnostic characters of the species and incorrect assumptions about the mode of reproduction. The literature is briefly reviewed and an approximate type locality from the Firth of Forth, Scotland, is identified. Alcyonidium mytili is comprehensively redescribed from material collected in the Firth of Forth and from 2 years' collections in the Daugleddau estuary, near Pembroke Dock, South Wales. Zooid and polypide dimensions and modal tentacle number (16) have been determined from large samples. Most importantly A. mytili possesses a conspicuous intertentacular organ when reproductive; is oviparous, with eggs discharged through the intertentacular organ developing into cyphonautes larvae; and has a prolonged winter reproductive period. The contrary indications in the literature are a consequence of confusion with a superficially similar but larviparous species.     

Ultrastructure of the body cavities in Phylactolaemata (Bryozoa)

Only species belonging to the bryozoan subtaxon Phylactolaemata possess an epistome. To test whether there is a specific coelomic cavity inside the epistome, Fredericella sultana, Plumatella emarginata, and Lophopus crystallinus were studied on the ultrastructural level. In F. sultana and P. emarginata, the epistome contains a coelomic cavity. The cavity is confluent with the trunk coelom and lined by peritoneal and myoepithelial cells. The lophophore coelom extends into the tentacles and is connected to the trunk coelom by two weakly ciliated coelomic ducts on either side of the rectum. The lophophore coelom passes the epistome coelom on its anterior side. This region has traditionally been called the forked canal and hypothesized to represent the site of excretion. L. crystallinus lacks an epistome. It has a simple ciliated field where an epistome is situated in the other species. Underneath this field, the forked canal is situated. Compared with the other species, it is pronounced and exhibits a dense ciliation. Despite the occurrence of podocytes, which are prerequisites for a selected fluid transfer, there is no indication for an excretory function of the forked canal, especially as no excretory porus was found. J. Morphol. 2009. © 2008 Wiley‐Liss, Inc.     

Selective enrichment of green sulfur bacteria in the presence of 4-aminobenzenesulfonate (sulfanilate)

A novel selective enrichment method is described for phototrophic green sulfur bacteria even in the presence of purple sulfur and purple nonsulfur bacteria using sulfanilate, which was discovered during efforts to selectively isolate sulfanilate-metabolizing anoxygenic phototrophic bacteria from marine habitats. Samples for these experiments were obtained from beaches, saltpans, subsurface mangrove soils, fish and prawn aquaculture ponds and backwaters of the East and West coasts of India. Photoorganoheterotrophic and photolithoautotrophic enrichments in the absence of sulfanilate predominantly yielded purple bacterial enrichments. In contrast, photolithoautotrophic enrichments in the presence of sulfanilate yielded green-colored enrichments from the same samples. Whole cell absorption spectra of the enrichment cultures revealed the presence of bacteriochlorophyll c and thus green phototrophic bacteria. Microscopic observation demonstrated the presence of sulfur globules outside the bacterial cells and the presence of non-motile cells, some of which had prosthecae. 16S rDNA sequences obtained from green sulfur bacterial strains isolated from enrichment cultures confirmed the presence of representatives of the green sulfur bacterial genera Prosthecochloris and Chlorobaculum. The selective pressure of sulfanilate exerted through inhibition of phototrophic purple sulfur bacteria was demonstrated by inhibition studies using the purple sulfur bacteria Marichromatium indicum JA100 and Marichromatium sp. JA120 (JCM 13533) and the green sulfur bacterium Prosthecochloris sp. JAGS6 (JCM 13299).     

Ecological distribution of the shrimp Pleoticus muelleri (Bate, 1888) (Decapoda: Penaeoidea) in southeastern Brazil

The abundance and ecological distribution of the shrimp Pleoticus muelleri as a function of certain environmental factors were investigated from January 1998 through December 1999 in the region of Ubatuba, São Paulo, Brazil. The collections were made monthly in the bays of Ubatumirim (UBM), Ubatuba (UBA) and Mar Virado (MV). Each bay was divided into six sampling transects, four transects parallel to the shoreline and two near the rocky shores on the opposite side. We employed a commercial shrimp boat equipped with two double-rig nets. A total of 6252 shrimp were collected, including 3321 from MV, 1467 from UBM, and 1464 from UBA. Most of the shrimp were caught in the deeper, higher-salinity areas. The high abundance of P. muelleri observed in the southern part of the region studied was related to a sediments with a higher percentage of silt and clay. The numbers of P. muelleri were positively correlated with periods of cooler temperatures. Thus, temperature and the type of sediment were determinant factors in the distribution of P. muelleri in this region.     

暗黑鳃金龟甲幼虫肠道细菌分离及鉴定

目的从微生态学角度研究暗黑鳃金龟甲幼虫营养生理活动,探讨其肠道菌群的构成,为其资源开发及生物防治提供理论依据。方法按传统分离方法,从暗黑鳃金龟甲幼虫肠道环境中分离纯化获得10个细菌菌株,对其菌体形态、染色反应、培养性状、生理生化反应进行了系统研究。结果研究结果表明,上述10个细菌菌株分别属于鲁氏耶尔森菌（Yersinia．ruckeri）、侧胞芽胞杆菌（Bacilluslaterosporus）、坚强芽胞杆菌（Bacillus．firmus）、放线杆菌属（Actinobacillus）、飞虫杀雄菌（Arsenophonusllasoniae）、不动杆菌属（Acinetobacter）、气单胞菌Aeromonas）、沙门菌属（Sal—moneUa）、短芽胞杆菌（Bacillusbrevis）、变形菌属（Proteus）。结论通过对暗黑鳃金龟甲幼虫肠道细菌的鉴定,其肠道细菌在培养性状、生理性状、生理生化测定等方面存在较多差异。     

Cystid Structure and Protrusion of the Polypide in Crisia (Bryozoa, Cyclostomata)

The ultrastructure of the cystid of Crisia eburnea has been studied. The cystid wall comprises an outer periostracum, a calcified layer and one inner cell layer, the ectoderm. The membranous sac, which consists of an outer basement membrane, a series of very thin annular muscle cells and an inner layer of epithelial cells, is interpreted as the detached mesoderm of the cystid wall. Accordingly, the atrial sphincter and the generally eight branched, longitudinal muscle cells connecting the terminal membrane and the membranous sac are interpreted as ectoderm. The membranous sac is attached to the cystid wall with two lateral ligaments and at four abfrontal areas: 1) a wide distal area, 2) an area at the origin of the retractor muscles, 3) a small area between 1 and 2, and 4) a small basal area at the origin of a pair of small muscle cells attached to the lowermost part of the caecum.
We infer that the protrusion of the polypide is caused by a sequential contraction of the annular muscle cells of the membranous sac, starting basally and aided by the contraction of the longitudinal ectodermal muscle cells.