Functional differentiation in bryozoan colonies: a proteomic analysis

Bryozoans are typical modular organisms. They consist of repetitive structural units, the zooids. Bryozoan colonies grow by zooidal budding, with the distribution pattern of the budding loci underlying the diversity of colony forms. Budding is usually restricted to the colony periphery, where a “growing edge” or local terminal growth zones are formed. Non-budding parts of the colony can be functionally subdivided, too. In many species colonies consist of regular, often repetitive zones of feeding and non-feeding modules, associated with a periodical degeneration and regeneration of the polypide retractile tentacle crown with a gut and the accompanying musculature. The mechanisms of functional differentiation in bryozoan colonies are unknown. Presumably, budding and/or polypide recycling are induced or inhibited by certain determinants of functional specialization in different colony parts. An effective tool of their identification is the comparison of proteomes in functionally different zones. Here we report the results of proteomic analysis of three bryozoan species from the White Sea with a different colony form: Flustrellidra hispida, Terminoflustra membranaceotruncata and Securiflustra securifrons. Using differential two-dimensional electrophoresis (2D-DIGE), we compared proteomes of the growing edge, the zone with polypides and the zone without polypides. We assessed the general level of differences between the zones and revealed proteins whose relative abundance changed gradually along the proximal-distal colony axis. These proteins might be involved in the determination of the functional differentiation of the colony.     

The inference of extrazooidal feeding currents in fossil bryozoan colonies

Taylor, Paul D. 1979 01 15: The inference of extrazooidal feeding currents in fossil bryozoan colonies. Lethaia , Vol. 12, pp. 47–56. Oslo. ISSN 0024–1164.
Previous studies on live bryozoan colonies have shown that the feeding autozooids in a colony may cooperate in differing ways to produce an extrazooidal watercurrent system organised on a colony-wide or subcolony-wide basis. The presence of an extrazooidal current system may be inferred in fossil stenolaemate bryozoans which exhibit either a differential spacing of open autozooecial apertures or a systematic variation across the marial surface in the orientation of automoecial distal portions. By inference, aggregations of autozooecial apertures represented loci of inhalant extrazooidal flow whereas zoarial protuberances (e.g. monticules) with outwardly leaning autozooecia acted as loci of exhalant extrazooidal flow. Bryozoans having automoecia opening obliquely into gaps or fenestrules in their zoaria probably drew a unidirectional extrazooidal current of water through the fenestrules. Extrazooidal water currents may function to accelerate colony clearance rate, decrease the chances of recycling filtered water, aid spermatoman and larval dispersal, and clear sediment from the colony surface.     

Zooid orientation structures and water flow patterns in Paleozoic bryozoan colonies

Anstey, Robert L. 1981 12 15: Zooid orientation structures and water flow patterns in Paleozoic bryotoan colonies. Lethaia . vol. 14, pp. 287–302. Oslo. ISSN 0024–1164.
By means of direct physical evidence provided by zooecial orientation structures, active water flow systems in Paleozoic bryozoans are inferred to be variously centripetal, centrifugal, or basipetal. Monticules, previously assessed as excurrent water outlets, fall into three additional functional types: incurrent, bypassed, and funnel. In one species circular zoarial fenestrations served as excurrent water outlets. Water flow patterns are strongly correlated with zoarial growth form, which vanes in a general way with inferred habitat conditions in ancient environments. Monticular astogeny and phylogeny include a graded series of sizes, types, and functions. Analogy with zooidal polarities in extant stenolaemates suggests that colony bases and centripetal monticules in the Paleozoic orders were anally budded, but that erect branches and centrifugal monticules were orally budded, a character shared only by the freshwater Phylactolaemata. * Bryozoa, Stenolaemata, functional morphology, monticule function, hydrodynamics, feeding currents, Palaeozoic .     

Variation in reproductive characteristics of colonies of the freshwater bryozoan Cristatella mucedo

1. We studied relationships between different forms of reproduction and local variation in the reproductive state of colonies of a common freshwater bryozoan Cristatella mucedo Cuvier (Bryozoa: Phylactolaemata). Four sampling locations in central Finland, including both lotic and lentic habitats, were sampled by scuba diving. The traits studied were occurrence of sexual larvae, colony size, number of resting stages (statoblasts) and number of zooids. 2. While 76.9% of the sampled colonies carried statoblasts at the time of sampling, only 4.5% of the colonies were brooding sexual larvae. Most of the colonies were relatively small with a mean colony size of 16.6 mm. 3. In colonies brooding larvae, the number of statoblasts was positively correlated with the number of larvae. We did not detect a colony size threshold for sexual reproduction or formation of statoblasts. Colonies carrying statoblasts had a lower number of zooids per unit dry weight. 4. We found significant variation in reproductive traits of colonies among the sampling locations, and among lotic and lentic habitats. The observed phenotypic differences may reflect broadly distributed, phenotypically plastic clones. Differences in clonal composition of local populations cannot, however, be ruled out and factors that may provide clonal diversity are discussed.     

Patterns of resource use within a population of xanthid crabs occupying bryozoan colonies

Summary Heads, i.e. colonies, of the bryozoan Schizoporella pungens are discrete resource units which protect the xanthid crab Pilumnus sayi from predation. The heads were spatially clumped, temporally stable, and differed both qualitatively and quantitatively. The number of adult P. sayi was equal to the number of heads with preferred characteristics, yet a relative shortage of this resource is suggested with concomitant intraspecific competition. Adult crabs occupied heads individually except for infrequent cases of double occupancy by a male and female. Further spatial pattern among crabs was consistent with a hypothesis that males defend clumps of heads occupied by females.     

The distribution of colonies of the bryozoan Antarctothoa bougainvillei on the red alga Hymenena laciniata

The cheilostome bryozoan Antarctothoa bougainvillei (d’Orbigny) is the most frequent epibiont on the ribbon-like red alga Hymenena laciniata (Hooker f. & Harvey) Kylin in San Sebastián Bay (Tierra del Fuego, Argentina). Twenty-one thalli and 1,484 colonies were examined to analyse the relationship between both species. In most cases, number and area of colonies did not differ significantly at both sides of the thallus. Ancestrulae (i.e., founder zooids originating colonies by asexual budding) were mostly oriented facing the algal growing edge. Colonies were more frequent on central than on marginal zones of the thalli. The population of A. bougainvillei was mainly composed of very small colonies (<10 mm²). Larger colonies predominated and intraspecific competition was more intense near the basal portions of the thalli. Fecundity (number of ovicells) increased at a significantly higher rate in colonies with margins obstructed by conspecific neighbours than in free-growing colonies. Colonies were significantly larger on somatic than on reproductive algal tissues. As total and reproductive surfaces covered by colonies of A. bougainvillei were on average very low (4.43% and 0.53%, respectively), this epibiont is not supposed to produce a negative effect on H. laciniata. Handling editor: T. P. Crowe     

Functional morphology of the cap-like apparatus in autozooids of a Palaeozoic trepostome bryozoan

A membranous, cap-like structure was discovered in the bryozoan genus Hallopora from upper Ordovician siltstones from Sardinia. The structure is interpreted to be analogous to the perimetrical attachment organ and to the part of the membranous sac sustaining the sphincter muscle in Recent cyclostomes. The progressive mineralization of the cap-like apparatus occurred in later ontogenetic stages of the colony in order to have the function of a terminal diaphragm. This diaphragm is related to a particular degeneration—regeneration cycle very similar to the cyclic growth patterns (intracolony overgrowths) of some post-Palaeozoic cyclostomes. After this phase the colony seems to end its life cycle.     

Functional morphology and taxonomy of branch dimorphism in the Paleozoic bryozoan genus Rhabdomeson

Silicified maria of the widespread cylindrical genus Rhabdomeson have been discovered that bear conical branches traditionally assignable to Coeloconus . Other, conical stems gave rise to cylindrical branches. That the dimorphic branches are not encrustations is shown by the absence of overgrowths and the regular alignment of apertures between parent stem and branch. A similar relationship is true of the type species of Coeloconus , which is synonymized with Rhabdomeson . Both conical and cylindrical branches were broken but survived to resume growth; this is shown by basal healing patterns and growth reversals. Colony fragmentation has been described in certain Cenozoic and modern bryozoans as a mode of increase, and is inferred to have been important in Rhabdomeson . The presence of fragmentation in taxonomically and stratigraphically widely separated bryozoans suggests that this mode of increase may be more important than realized.     

Functional differences between cells from MLR colonies grown in soft agar cultures

This report describes a method of growing soft agar colonies of human T lymphocytes activated in the MLR. Two types of colonies were demonstrated: lower colonies grew within the agar layer, and upper colonies grew on the surface of the agar layer. Three days of priming the lymphocytes in the MLR and the use of supernatants of day-3 MLR cultures to provide T cell colony growth factor were necessary for optimal colony formation. Lymphocytes obtained from colonies were grown in long-term (2 to 4 weeks) cultures to generate sufficient numbers of cells to be tested in different functional assays. Cells from both types of colonies exhibited PLT activity. Upper colony cells showed considerably higher CML activity than lower colony cells (mean percent cytotoxicity 37 +/- 5 vs 6 +/- 3). Cells from both types of colonies contained radiosensitive suppressor cell activity that inhibited the primary MLR. The suppressor cell effect of lower colony cells was specific for the original stimulator, but upper colony cells displayed nonspecific suppressive effects. For both types of colony cells, it appeared that suppressive effects were unrelated to the CML activity of these cells. These data suggest that the soft agar colony assay offers a promising approach to separate subpopulations of lymphocytes activated in the MLR.     

Asymptotic analysis of a chemotactic model of bacteria colonies

An estimate of the distance between spots generated by a bacterial colony model is obtained. The model describes the morphogenesis of a spot pattern in colonies of chemotactic strains of Escherichia coli. Asymptotic methods for other cell-chemotaxis models, which have been successfully used by previous researchers, can be applied also to this model. However the calculations and the result is more complicated for this model. The result is verified by comparing it with the results by numerical computations of solutions of the model.     

Toward organism identification through analysis of bacterial colonies.

The clinical problem of bacterial identification has been approached by applying pattern-recognition techniques to multi-wavelength surface-scattering and reflectance data derived from real-time scans of isolated colonies. Preliminary results, obtained from blood-agar plates inoculated with a mixture of staphylococci, streptococci and escherichieae, indicate that these organisms can be differentiated with better than 90% certainty, provided the colonies are physically separated and their growth conditions closely controlled. Data collection and classification characteristics of the experimental system are briefly described; it is felt that the technique, possibly expanded to include boundary characteristics of the colonies, may offer a viable means of identifying clinically important bacteria.     

Acquisition of small colonies ofTrichoderma viride for genetic analysis

Growth and mutual interlacing of colonies of T. viride is affected by concentration of nutrients and presence of inhibitors in the culture medium. The most convenient colony restrictors were Bengal red, Ox Gall and sodium deoxycholate while L-sorbose and 2-deoxy-D-arabino-hexose were less efficient.     

Pattern analysis in bryozoan and spirorbid communities. II. Distance sampling methods

The spatial pattern of settlements of the bryozoan Alcyonidium polyoum (Hassall) and of Spirorbis spirorbis (L.) on plastic (Perspex) disks has been examined using nearest-neighbour analysis. Cumulative frequency distributions of ω = r², where r is the distance from each individual to its nearest neighbour, have been set up and compared with those expected assuming random settlement on each disk. Deviation above the expected line indicates aggregation and deviation below it indicates regularity or spacing apart. At low densities (< 7.4 cm^?2) Spirorbis settlements were demonstrably aggregated and at high densities (> 18.2 cm^?2) they displayed spacing apart. Alcyonidium ancestrulae showed aggregation at all densities (1.4–45.6 cm^?2) under the null hypothesis that when a larva encounters an ancestrula it moves away and settles randomly elsewhere. Truncating the cumulative distributions to consider only the settlement within aggregations still showed no evidence of spacing apart. Under a different null hypothesis, that a larva encountering an ancestrula settles contiguously to it, spacing apart was demonstrated only at unnaturally high densities (> 13 cm^?2). It is concluded, on the basis of observed larval exploratory behaviour and naturally occurring settlement densities, that settling Alcyonidium larvae do not space apart. The biological significance of this finding is discussed.     

Genetic analysis of mutagenesis in aging Escherichia coli colonies

Bacteria live in unstructured and structured environments, experiencing feast and famine lifestyles. Bacterial colonies can be viewed as model structured environments. SOS induction and mutagenesis have been observed in aging Escherichia coli colonies, in the absence of exogenous sources of DNA damage. This cAMP-dependent mutagenesis occurring in Resting Organisms in a Structured Environment (ROSE) is unaffected by a umuC mutation and therefore differs from both targeted UV mutagenesis and recA730 (SOS constitutive) untargeted mutagenesis. As a recB mutation has only a minor effect on ROSE mutagenesis it also differs from both adaptive reversion of the lacI33 allele and from iSDR (inducible Stable DNA Replication) mutagenesis. Besides its recA and lexA dependence, ROSE mutagenesis is also uvrB and polA dependent. These genetic requirements are reminiscent of the untargeted mutagenesis in λ phage observed when unirradiated λ infects UV-irradiated E. coli. These mutations, which are not observed in aging liquid cultures, accumulate linearly with the age of the colonies. ROSE mutagenesis might offer a good model for bacterial mutagenesis in structured environments such as biofilms and for mutagenesis of quiescent eukaryotic cells. Received: 30 April 1997 / Accepted: 1 July 1997     

Functional analysis of protein ubiquitination

Alterations in the protein ubiquitination can lead to the development of serious pathological conditions and diseases and, therefore, are under extensive investigation. Here we detail the revised/updated version of two approaches for analyzing the functional activities of the ubiquitin transferring system and target protein ubiquitination. These approaches permit the analysis of protein ubiquitination within the cellular environment as well as in a tube when the purified components are used. The updates introduced in the protocols allow both to increase the sensitivity of the assays and to reduce the false positives often experienced in the analyses.     

Functional analysis of beef tenderness

Meat tenderness represents a complex assembly of different cellular pathways. As a consequence, genomics studies have revealed many different proteins considered as tenderness markers. So it is difficult to have an overview of tenderness in terms of cellular pathways. In this work cellular pathways of tenderness were analyzed, an interactome of 330 proteins was designed, and explanations of tenderization processes were proposed.     

Functional analysis of zebrafish GDNF

We have identified zebrafish orthologues of glial cell line-derived neurotrophic factor (GDNF) and the ligand-binding component of its receptor GFRalpha1. We examined the mRNA expression pattern of these genes in the developing spinal cord primary motor neurons (PMN), kidney, and enteric nervous systems (ENS) and have identified areas of correlated expression of the ligand and the receptor that suggest functional significance. Many aspects of zebrafish GDNF expression appear conserved with those reported in mouse, rat, and avian systems. In the zebrafish PMN, GFRalpha1 is only expressed in the CaP motor neuron while GDNF is expressed in the ventral somitic muscle that it innervates. To test the functional significance of this correlated expression pattern, we ectopically overexpressed GDNF in somitic muscle during the period of motor axon outgrowth and found specific perturbations in the pattern of CaP axon growth. We also depleted GDNF protein in zebrafish embryos using morpholino antisense oligos and found that GDNF protein is critical for the development of the zebrafish ENS but appears dispensable for the development of the kidney and PMN.