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1.
Topological patterns in the development and evolution of metazoa, from sponges to chordates, are considered by means of previously elaborated methodology, with the genus of the surface used as a topological invariant. By this means metazoan morphogenesis may be represented as topological modification(s) of the epithelial surfaces of an animal body. The animal body surface is an interface between an organism and its environment, and topological transformations of the body surface during metazoan development and evolution results in better distribution of flows to and from the external medium, regarded as the source of nutrients and oxygen and the sink of excreta, so ensuring greater metabolic intensity. In sponges and some Cnidaria, the increase of this genus up to high values and the shaping of topologically complicated fractal-like systems are evident. In most Bilateria, a stable topological pattern with a through digestive tube is formed, and the subsequent topological complications of other systems can also appear. The present paper provides a topological interpretation of some developmental events through the use of well-known mathematical concepts and theorems; the relationship between local and global orders in metazoan development, i.e., between local morphogenetic processes and integral developmental patterns, is established. Thus, this methodology reveals a “topological imperative”: A certain set of topological rules that constrains and directs biological morphogenesis.  相似文献   

2.
Marine sponges in the genus Ircinia are known to be good sources of secondary metabolites with biological activities. A major obstacle in the development of sponge-derived metabolites is the difficulty in ensuring an economic, sustainable supply of the metabolites. A promising strategy is the ex situ culture of sponges in closed or semiclosed aquaculture systems. In this study, the marine sponge Ircinia strobilina (order Dictyoceratida: family Irciniidae) was collected from the wild and maintained for a year in a recirculating aquaculture system. Microbiological and molecular community analyses were performed on freshly collected sponges and sponges maintained in aquaculture for 3 months and 9 months. Chemical analyses were performed on wild collected sponges and individuals maintained in aquaculture for 3 months and 1 year. Denaturing gradient gel electrophoresis was used to assess the complexity of and to monitor changes in the microbial communities associated with I. strobilina. Culture-based and molecular techniques showed an increase in the Bacteroidetes and Alpha- and Gammaproteobacteria components of the bacterial community in aquaculture. Populations affiliated with Beta- and Deltaproteobacteria, Clostridia, and Planctomycetes emerged in sponges maintained in aquaculture. The diversity of bacterial communities increased upon transfer into aquaculture.  相似文献   

3.
Abstract. Four copepod species of the genus Asterocheres (A. echinicola, A. latus, A. suberitis and A. complexus ) are recorded for the first time as associated with Mediterranean sponges of the classes Calcarea and Demospongiae (orders Dictyoceratida, Dendroceratida, and Poecilosclerida). Individuals of A. suberitis are described for the first time as inhabiting sponges other than Suberites domuncula . The copepods seemed to use their trunk to suck the material (cuticles or excreted cells) produced at the sponge periphery (ectosome), which indicates that their feeding habits are similar to those observed in species of the same genus that feed on exfoliated tissues of echinoderms. In the laboratory, copepods fed on young sponges (rhagons) of the species Crambe crambe, Cacospongia mollior , and Dysidea avara without reducing the rhagon biomass. In contrast, rhagons of the species Haliclona sp., Hymedesmia spp., and Phorbas tenacior were consumed and their biomass reduced. This may be because the latter group does not produce external proteinaceous material. Copepod offspring were continuously released (∼6 nauplii every 48 h) and the larval stages were capable of limited swimming. We found significantly more copepods over the surface of the sponges than inside them. Copepod abundance was positively correlated with the sponge surface area while not with the sponge biomass. These results indicate that the copepods live preferentially over the sponge surface and that their abundance is surface-area dependent. The behavioral traits described here indicate that the interactions between asterocherid species and sponges are worthy of future study.  相似文献   

4.
It was found that cells of different color morphs of the cold-water marine sponges Halichondria panicea (Pallas, 1766) of the class Demospongiae differ in the content of epibionts of bacteria of the genus Pseudoalteromonas. The sponge cells with elevated levels of epibionts of bacteria of the genus Pseudoalteromonas showed an increased expression of Hsp70 proteins but had a reduced level of the proteasomal catalytic beta 5 subunit, which was accompanied by a change in their activity. Probably, epibionts of bacteria of the genus Pseudoalteromonas may affect the ubiquitin–proteasome system in the cells of cold-water marine sponges and, thereby, ensure their adaptive plasticity.  相似文献   

5.
In order to investigate the relationships between species of the genus Pasteurella sensu stricto such as Pasteurella multocida, Pasteurella canis, Pasteurella stomatis, Pasteurella dagmatis, Pasteurella avium, Pasteurella volantium, Pasteurella gallinarum, Pasteurella species A, Pasteurella species B and "Pasteurella leonis" MCCM 00659 their genomic fingerprints and ARDRA profiles were compared and their quinone systems were analysed. Visual comparison of band patterns from rep-PCR (ERIC-, REP- and BOX-PCR) and the analyses of the combined band patterns by UPGMA (unweighted pair group method with averages) dendrogram derived from the combined fingerprint profiles demonstrated that each strain displays a distinct genomic fingerprint. In members of the same species several similarities in the band patterns were observed. Combined ARDRA profiles, obtained after digestion of amplified 23S rRNA coding genes with the enzymes DdeI, MseI and RsaI, revealed a dissection of the members of the genus Pasteurella sensu stricto into two groups which was in agreement with the two groups obtained from our analyses of the quinone systems. These two groups corresponded with the two phylogenetically determined subclusters 3A and 3B described previously. The species of subcluster 3A displayed a quinone system with ubiquinone Q-7 (32-56%) and ubiquinone Q-8 (44-63%) as major compounds. Members of subcluster 3B had a quinone system with ubiquinone Q-8 (86-97%) as the major compound. Based on these results it can be suggested that the genus Pasteurella sensu stricto should be restricted to the species of subcluster 3B including the species Pasteurella multocida, Pasteurella canis, Pasteurella stomatis, Pasteurella dagmatis and Pasteurella species B. In addition, evidence was found which would indicate that: 1) Pasteurella canis MCCM 00927 is misnamed and should be reclassified with Pasteurella multocida; 2) Pasteurella multocida subsp. septica may be classified as a separate species; and 3) "Pasteurella leonis" MCCM 00659 represents a separate species within subcluster 3B and thus could be described as a species of Pasteurella sensu stricto (also in a redefined genus) when more strains become available.  相似文献   

6.
Freshwater sponges play a major role in freshwater ecological system as important filter-feeding organisms and bioindicators. There are only few data about their ecological diversity and population genetic structure available, though a deeper knowledge is needed to propose proper conservation and effective management. The aim of this study was to assess data on distribution patterns of freshwater sponges to study the connectivity of genotypes of Ephydatia fluviatilis in a river system. We sampled specimens from River-Sieg system (River Agger and River Sieg, Germany). We hypothesized that strong anthropogenic influence would cause a uniform distribution of population structures. The genetic structure of E. fluviatilis populations was analysed with a set of eleven microsatellite loci from seven locations in River-Sieg system. Besides of E. fluviatilis, three other species co-occurred (Ephydatia mülleri, Spongilla lacustris, Eunapius fragilis). In contrast to our hypothesis, we observed an overall correlation between genetic and geographic distances among populations of this sessile species, which follows a clear isolation-by-distance pattern. A significant microsatellite polymorphism and high levels of genetic divergence between populations (FST) in upstream reaches were present. These results will provide important information for conservation management of populations with limited dispersal ability in connected river systems.  相似文献   

7.
Abundant and well-preserved assemblages of disarticulated sponge spicules occur in Middle and Late Cambrian platform carbonates of western Hunan, China. Assemblages recovered from 11 stratigraphic horizons include calcisponges, demosponges, and hexactinellids. Hexactinellida, in particular, are both abundant and diverse in Upper Cambrian carbonates. Comparison with spicule assemblages from Australia indicates that many of these taxa have long stratigraphic ranges, limiting their use in correlation. The morphological diversity of these spicules exceeds that known for living siliceous sponges, supporting the observation that during the Cambrian radiation, sponges, like other metazoans, evolved a variety of architectural forms not observed in later periods. Like conodonts, individual sponges can produce more than one spicule form; thus, an "apparatus genus" concept based on multiple co-occurring elements may eventually prove useful in the biostratigraphic and paleobiological interpretation of disarticulated sponge spicules. Four distinctive forms are recognized as new taxa: Australispongia sinensis new genus and species, Flosculus gracilis new genus and species, Pinnatispongia bengtsoni new genus and species, and Nabaviella paibiensis new species.  相似文献   

8.
9.
Among 1,236 colony-forming units (CFU) associated with 11 species of marine sponges collected from a Brazilian coast, a total of 100 morphologically different bacterial strains were analyzed. The phylogenetic diversity of the bacterial isolates was assessed by 16S rRNA gene amplification—restriction fragment length polymorphism (RFLP) analysis, using AluI restriction endonuclease. The RFLP fingerprinting resulted in 21 different patterns with good resolution for the identification of the bacterial isolates at the genus level. The genus Bacillus was the most commonly encountered genus, followed by Kocuria. Regarding the relationship between the morphotypes and species of marine sponges, Mycale microsigmatosa presented major diversity, followed by Dragmacidon reticulatum and Polymastia janeirensis. An antibiotic susceptibility profile of the 100 sponge-associated bacterial strains was determined by the disk diffusion method, and we observed a variable resistance profile, with 15 % of the bacteria being multiresistant. In addition, 71 of 100 strains were able to produce biofilm. These 71 strains were divided into 20 strong biofilm producers, 10 moderate biofilm producers, and 41 weak biofilm producers. The plasmid profile of the 100 bacterial strains was analyzed and 38 (38 %) of these samples possessed one or more plasmids. Studies like this are important to increase the information on these associated bacteria found off the coastline of Brazil, a place which has rich biodiversity that is still unknown.  相似文献   

10.
Helicobacter pylori is one of the most prevalent human pathogens in the world and is the aetiological agent of gastritis, peptic ulcer disease and gastric malignancies. In addition H. pylori and other novel members of the genus are capable of successfully colonising the bile-rich niche of the upper intestine and are associated with a diverse range of intestinal pathologies. Surface-enhanced laser desorption/ionisation-time of flight mass spectrometry was used to analyse surface extracts from H. pylori, Helicobacter bilis, Helicobacter pullorum and "Helicobacter sp. flexispira" to characterise cell surface changes following bile stress. The system detected two distinct response patterns to bile stress on the cell surface of Helicobacter spp. in vitro. The first involved the increase under bile stress of peaks at 7.6 and 7.9 kDa for H. billis and H. pullorum, respectively. In contrast both "Helicobacter sp. flexispira" and a clinical isolate of H. pylori had similar response profiles to bile stress. Both strains had at least three low mass peaks decreased under bile stress and a single peak induced by bile stress. The present study has established the use of ProteinChip(R) technology to analyse helicobacter-related proteomics. Specifically this study has established that different patterns are generated in response to bile stress among various pathogenic Helicobacter spp. which may give insights into the ability of these strains to colonise different niches.  相似文献   

11.
Resolving the infrageneric classification of species-rich genera has been challenging in plant taxonomy. Ilex L. is a subcosmopolitan genus with over 600 species of dioecious trees and shrubs. Many classification systems based on morphological data have been proposed during the past 250 years. However, these systems (such as Loesener's and Galle's systems) may not truly reflect Ilex's evolutionary trajectories because most of those system's infrageneric hierarchies are not monophyletic. In this study, we reconstructed a phylogeny of Ilex L. comprising 15 moderately to highly supported clades using rigorously identified samples (202 species) and closely authenticated gene sequences of three nuclear genes [internal transcribed spacer (ITS), external transcribed spacer (ETS), and nepGS]. The newly generated phylogenetic tree resembles essentially that of the nuclear tree of Manen et al., but shows conspicuous topological differences with the phylogeny of Yao et al. Closely scrutinizing morphological variation and distributional patterns of 202 species, this study found that most lineages of Ilex identified herein are well defined by a particular trait or a combination of morphological and distributional traits, displaying phylogeny–morphology–distribution conformity that has seldom been uncovered in previous studies. Given the general phylogeny–morphology–distribution conformity revealed in this genus, we put forward an updated sectional classification system for Ilex that temporarily contains 14 sections. The new classification will provide a robust framework for studying the evolution and diversification of this ecologically and economically important genus.  相似文献   

12.
Bacterial communities associated with the surfaces of several Mediterranean sponge species (Agelas oroides, Chondrosia reniformis, Petrosia ficiformis, Geodia sp., Tethya sp., Axinella polypoides, Dysidea avara, and Oscarella lobularis) were compared to those associated with the mesohyl of sponges and other animate or inanimate reference surfaces as well as with those from bulk seawater. Denaturing gradient gel electrophoresis (DGGE) analysis of PCR-amplified bacterial 16S ribosomal RNA genes obtained from the surfaces and tissues of these sponges demonstrated that the bacterial communities were generally different from each other. The bacterial communities from sponges were different from those on reference surfaces or from bulk seawater. Additionally, clear distinctions in 16S rDNA fingerprint patterns between the bacterial communities from mesohyl samples of "high-microbial abundance (HMA) sponges" and "low-microbial abundance sponges" were revealed by DGGE and cluster analysis. A dominant occurrence of particularly GC-rich 16S ribosomal DNA (rDNA) fragments was found only in the DGGE banding pattern obtained from the mesohyl of HMA sponges. Furthermore, sequencing analysis of 16S rDNA fragments obtained from mesohyl samples of HMA sponges revealed a dominant occurrence of sponge-associated bacteria. The bacterial communities within the mesohyl of HMA sponges showed a close relationship to each other and seem to be sponge-specific.  相似文献   

13.
14.
Two models of wound repair compared the effect of defined, recombinant growth factors on the rate of wound repair in both normal and streptozotocin-induced diabetic rats: subcutaneous implantation of polyvinyl alcohol sponges and incisional wounding. Transverse incisional wounds were made on the dorsal surface of rats and closed with steel sutures. Three days postwounding the rats received a single injection of either transforming growth factor-beta or vehicle alone directly into the wound site. Animals were sacrificed 7, 14, and 21 days postwounding, and fresh and formalin-fixed wound tensile strength were measured. Diabetic rats had expected defects in wound repair, including decreased granulation tissue and reduced amounts of collagen, protein, and DNA. Fresh tensile strength of the diabetic incisions was 53% of normal on Day 7 (p < or = .01) and 29% of normal on Day 21. Fixed tensile strength was 41% of normal on Day 7 (p < or = .01) and fell to 78% of normal by Day 21 (p < or = .01), suggesting that collagen concentrations of diabetic wounds increased towards normal but did not undergo maturation. TGF beta produced a moderate increase in tensile strength of fresh and fixed wounds of diabetic rats, but not to the levels of wounds in untreated normal rats. Sponges fill with granulation tissue, their reproducible rate of organization being measured by histological and biochemical methods. A single injection into sponges 3 days postimplantation of basic fibroblast growth factor, transforming growth factor-beta, or vehicle only, was evaluated at 7 and 9 days postimplantation. In the sponge model, bFGF and TGF beta were each able to induce significant increases in the accumulation of granulation tissue in both diabetic and normal rats. TGF beta increased the collagen content of sponges by 136% in sponges from diabetic animals (p < or = .001), thereby raising the collagen content to that of normal control wounds, while stimulating a 49% (p < or = .02) increase in sponges from normal animals on Day 9. By contrast, the response to bFGF was predominantly an increase in the protein and DNA content of the sponges. These results emphasize the differential effects of the two cytokines in accelerating healing under conditions of defective wound repair.  相似文献   

15.
Here we report, for the first time, a very rich and diversified sponge assemblage from late Early Miocene deposits of a central part of the Vienna Basin (Paratethys) in Slovakia. Bodily preserved sponges are described as a new genus and species Paracinachyrella fossilis (Tetiliidae, Demospongiae). Dissociated spicules reveal the presence of the “soft” demosponges that belong to families Tetillidae, Theneidae, Geodiidae, Samidae, Thrombidae, Thoosidae, Agelasidae, Myxillidae, Bubaridae, and Tedaniidae, the lithistid family Pleromidae, and an undetermined rhizoclone-bearing lithistid. Fragments of dictyonal skeleton indicate the presence of hexactinellid sponges that belong to the families Farreidae and Euretidae, and lychniscosan sponges. We estimate that at least 16–19 different species of siliceous sponges inhabited this region of the Central Paratethys during the latest Burdigalian. Most of these sponges are reported for the first time from the Miocene of the Paratethys. This sponge fauna has clear Tethyan affinities and indicates the existence of connection between Paratethys and Tethys during the latest Burdigalian, as well as the presence of open marine, deep-water, bathyal conditions in this part of the Vienna Basin.  相似文献   

16.
Summary The compensatory optomotor turning reaction as well as the turning response towards objects play an important role in visual orientation. On the basis of behavioural experiments under precisely defined stimulus conditions it is concluded that in female house-flies these motion-dependent responses are mediated by two parallel control systems with different dynamic and spatial integration properties. One of them (large-field system) is most sensitive to the motion of large textured patterns and controls the yaw torque mainly at low oscillation frequencies (below 0.1 Hz) of the stimulus panorama. In contrast, the other control system (small-field system) is tuned to the detection of relatively small moving patterns and shows its strongest responses at high oscillation frequencies (between 1 and 4 Hz), i.e. in a frequency range where the large-field system contributes to the turning response with only a relatively small gain.In free flight, house-flies do not curve smoothly but in sequences of rapid turns which induce retinal large-field motion of continually changing sign (Wagner 1986b). The dynamic properties of the large-field system might thus be interpreted as a simple strategy to almost eliminate the unwanted optomotor yaw torque induced by active self-motion. In contrast, the small-field system might still be operational under these conditions.  相似文献   

17.
Ise Y  Vacelet J 《Zoological science》2010,27(11):888-894
Two new species of carnivorous sponges of the genus Abyssocladia are described. These sponges were collected from Myojin Knoll, Izu-Ogasawara (Izu-Bonin) Arc, in southern Japan. Detailed morphological observation based on specimen both in situ and preserved revealed functional differentiation of spicule distribution. Abyssocladia natsushimae sp. nov. is distinct within the genus in its mop-like gross morphology, large body size, and soft tissue packed with numerous microspined microstrongyles. Abyssocladia myojinensis sp. nov. is characterized by possession of both typical abyssochelae and palmate abyssochelae. This is the first record of the genus from Japan.  相似文献   

18.
To better understand the developmental mechanisms of color pattern variation in butterfly wings, it is important to construct an accurate representation of pattern elements, known as the "nymphalid groundplan". However, some aspects of the current groundplan remain elusive. Here, I examined wing-wide elemental patterns of various nymphalid butterflies and confirmed that wing-wide color patterns are composed of the border, central, and basal symmetry systems. The central and basal symmetry systems can express circular patterns resembling eyespots, indicating that these systems have developmental mechanisms similar to those of the border symmetry system. The wing root band commonly occurs as a distinct symmetry system independent from the basal symmetry system. In addition, the marginal and submarginal bands are likely generated as a single system, referred to as the "marginal band system". Background spaces between two symmetry systems are sometimes light in coloration and can produce white bands, contributing significantly to color pattern diversity. When an element is enlarged with a pale central area, a visually similar (yet developmentally distinct) white band is produced. Based on the symmetric relationships of elements, I propose that both the central and border symmetry systems are comprised of "core elements" (the discal spot and the border ocelli, respectively) and a pair of "paracore elements" (the distal and proximal bands and the parafocal elements, respectively). Both core and paracore elements can be doubled, or outlined. Developmentally, this system configuration is consistent with the induction model, but not with the concentration gradient model for positional information.  相似文献   

19.
A possibility of correlative formation in ontogenesis of central mechanisms of stereognosis and speech function is considered in the paper by example of comparison of changes in spatial organization of interregional interaction of various cortex areas in children of three ages (5-6, 7-8 and 9-10 years) and in adult examinees during their performances of stereognostical, verbal-mnestical and motor manual activity (tepping-test). With age dynamics of children there is observed a significant increase of the degree of similarity of the spatial structure of EEG interrelations characteristic of periods of performance of stereognostical test with patterns of changes of the EEG distant connections revealed at performance of speech tasks. In turn, the similarity of patterns of interregional EEG relations characteristic of stereognostical tasks with the patterns revealed at the periods of performance of the tepping-test is not increased with age. On the whole, the obtained data allow believing that with increase of children's age there rises the degree of topological similarity of the spatial structure of systemic interactions of the cortex zones, on which there are "supported" processes of realization of stereognostical and speech functions. Progressing increase with children's age of the degree of similarity of distributive organization of neurophysiological mechanisms of central provision of the speech and stereognosis functions can indicate in favor of concept of correlative formation of these higher psychical functions in postnatal ontogenesis. The obtained results show that the correlative interfunctional interactions promoting progressive development of cognitive functions in the child ontogenesis can be realized through long fiber associated and commissural pathways composing the morphofunctional longitudinal-transversal "skeleton" ofneocortex in the close interaction with thalamo-cortical integrative systems.  相似文献   

20.
The 2016 Nobel Prizes were awarded to Yoshinori Ohsumi for autophagy and to David Thouless, Duncan Haldane and Michael Kosterlitz for topological transitions. Both of these phenomena are intrinsically related when it comes to membranes. Here, we give a brief account on topological transformations of lipid membranes, commonly known as membrane fusion and membrane scission, and introduce the underlying topological invariant, the genus. The genus of a shape is a useful concept to distinguish unambiguously the processes of membrane fusion/scission and offers a simple method to describe complex, cellular membrane structures, such as fenestrated cristae. We distinguish and highlight the connection between topological transformations of lipid membranes and the recent awards, and point out the extraordinarily large number of topological changes during autophagy.   相似文献   

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