Adsorption kinetics of laterally and polarly flagellated Vibrio.

The adsorption of laterally and polarly flagellated bacteria to chitin was measured, and from the data obtained, a modified Langmuir adsorption isotherm was derived. Results indicated that the adsorption of laterally flagellated Vibrio parahaemolyticus follows the Langmuir adsorption isotherm, a type of adsorption referred to as surface saturation kinetics, when conditions are favorable for the production of lateral flagella. When conditions were not favorable for the production of lateral flagella, bacterial adsorption did not follow the Langmuir adsorption isotherm; instead, proportional adsorption kinetics were observed. The adsorption of some polarly flagellated bacteria exhibited surface saturation kinetics. However, the binding index (the product of the number of binding sites and bacterial affinity to the surface) of polarly flagellated bacteria differed significantly from that of laterally flagellated bacteria, suggesting that polarly flagellated bacteria adsorb to chitin by a different mechanism from that used by the laterally flagellated bacteria. From the results of dual-label adsorption competition experiments, in which polarly flagellated V. cholerae competed with increasing concentrations of laterally flagellated V. parahaemolyticus, it was observed that laterally flagellated bacteria inhibited the adsorption of polarly flagellated bacteria. In contrast, polarly flagellated bacteria enhanced the adsorption of V. cholerae. In competition experiments, where V. parahaemolyticus competed against increasing concentrations of other bacteria, polarly flagellated bacteria enhanced V. parahaemolyticus adsorption significantly, whereas laterally flagellated bacteria only slightly enhanced the process. The direct correlation observed between surface saturation kinetics, the production of lateral flagella, and the ability of laterally flagellated bacteria to inhibit the adsorption of polarly flagellated bacteria suggests that lateral flagella represent a component of bacterial structure that is important in the adsorption of laterally flagellated bacteria to surfaces. A model for adsorption events of laterally flagellated bacteria is proposed, based on the evidence presented.     

Metamorphosis of cinctoblastula larvae (Homoscleromorpha, porifera)

The metamorphosis of the cinctoblastula of Homoscleromorpha is studied in five species belonging to three genera. The different steps of metamorphosis are similar in all species. The metamorphosis occurs by the invagination and involution of either the anterior epithelium or the posterior epithelium of the larva. During metamorphosis, morphogenetic polymorphism was observed, which has an individual character and does not depend on either external or species specific factors. In the rhagon, the development of the aquiferous system occurs only by epithelial morphogenesis and subsequent differentiation of cells. Mesohylar cells derive from flagellated cells after ingression. The formation of pinacoderm and choanoderm occurs by the differentiation of the larval flagellated epithelium. This is possibly due to the conservation of cell junctions in the external surface of the larval flagellated cells and of the basement membrane in their internal surface. The main difference in homoscleromorph metamorphosis compared with Demospongiae is the persistence of the flagellated epithelium throughout this process and even in the adult since exo- and endopinacoderm remain flagellated. The antero-posterior axis of the larva corresponds to the baso-apical axis of the adult in Homoscleromorpha.     

Motility of flagellated bacteria in viscous environments.

The lowest viscosity that immobilized flagellated bacteria such as Psedomonas aeruginosa, Spirillum serpens, and Escherichia coli was 60 centipoise (cp). Much higher viscosities (1,000 cp and higher) were required to immobilize two flagellated bacteria selectively isolated from nature by methods based on their ability to migrate through agar gels. The latter finding indicates that certain flagellated bacteria have the ability to swim through environments of relatively high viscosity. It is suggested that these flagellated bacteria possess a specialized type of motility apparatus suited to viscous conditions present in their habitats.     

Larval development in the Homoscleromorpha (Porifera, Demospongiae)

Abstract. Embryonic development from coeloblastula to fully developed larva was investigated in 8 Mediterranean homoscleromorph species: Oscarella lobularis, O. tuberculata, O. microlobata, O. imperialis, Plakina trilopha, P. jani, Corticium candelabrum , and Pseudocorticium jarrei. Morphogenesis of the larva is similar in all these species; however, cell proliferation is more active in species of Oscarella than in Plakina and C. candelabrum. The result of cell division is a wrinkled, flagellated larva, called a cinctoblastula. It is composed of a columnar epithelium of polarized, monoflagellated cells among which are scattered a few non-flagellated ovoid cells. The central cavity always contains symbiotic bacteria. Maternal cells are also present in O. lobularis, O. imperialis , and P. jarrei. In the fully developed larva, cell shape and dimensions are constant for each species. The cells of the anterior pole have large vacuoles with heterogeneous material; those of the postero-lateral zone have an intranuclear paracrystalline inclusion; and the flagellated cells of the posterior pole have large osmiophilic inclusions. Intercellular junctions join the apical parts of the cells, beneath which are other specialized cell junctions. A basement membrane underlying the flagellated cells lines the larval cavity. This is the first observation of a basement membrane in a poriferan larva. The basal apparatus of flagellated cells is characterized by an accessory centriole located exactly beneath the basal body. The single basal rootlet is cross striated. The presence of a basement membrane and a true epithelium in the larva of Homoscleromorpha—unique among poriferan clades and shared with Eumetazoa—suggests that Demospongiae could be paraphyletic.     

Untersuchungen zum Körperbau von Meeresschwämmen. II. Das Wasserleitungssystem vonHalichondria panicea

The water-conducting system ofHalichondria panicea (Pallas) shows the classical eurypylous type. The excurrent system consists of a multiple anastomosing network of channels, within which numerous flagellated chambers are embedded in such a way that their apopyles open into the excurrent canals. Each flagellated chamber communicates with the incurrent system by way of several prosopyles.     

Spherical forms ofTrichoplax adhaerens (Placozoa)

Summary Two types of spherical forms of this normally flattened organism appear sporadically in our cultures. Hollow spheres have an outer wall of flagellated ventral epithelium. The large fiber cells protrude into the central cavity which can include a closed compartment of flagellated dorsal epithelium. Cells of the outer wall that withdraw their flagellum and leave the epithelium are phagocytozed by fiber cells. Solid spheres consist of an outer layer of dorsal epithelium and densely packed fiber cells in the interior that may also include a closed compartment of ventral epithelium cells. Closely apposed fiber cells may form special cell contacts or pores connecting the cells.     

Colonic spirochetosis of colony-raised rhesus macaques associated with Brachyspira and Helicobacter

Colonic spirochetosis is an inflammatory bowel disease that affects a broad range of hosts, including human and non-human primates. The disease in humans and non-human primates is characterized by intimate attachment of the anaerobic spirochetes Brachyspira aalborgi and B. pilosicoli, and some unclassified flagellated microbes along the apical membrane of colonic enterocytes. Although the presence of spiral-shaped bacteria with single polar flagella and blunted ends in colonic spirochetosis is well established, the identities of many of these organisms is still unknown. Recently, Helicobacter species with a morphology similar to the flagellated bacteria present in colonic spirochetosis have been cultured from intestinal specimens obtained from rhesus macaques, some with idiopathic colitis. The purpose of the present study was to determine whether or not the flagellated bacteria seen in the colons of rhesus macaques with colonic spirochetosis are Helicobacter. The presence of flagellated bacteria alone (n=2) or together with spirochetes (n=1) in formalin-fixed and paraffin-embedded colons of three rhesus macaques with the naturally occurring disease was demonstrated by immunohistochemical staining and ultrastructural examination. Total DNA extracted from affected and control intestinal specimens was amplified by polymerase chain reaction (PCR) using Helicobacter 16S rRNA gene-specific primers. Comparative nucleotide sequence analysis of PCR products cloned from positive reactions indicated that two distinct Helicobacter genomospecies were present either alone or in combination with Brachyspira in the colons of rhesus macaques with microscopic lesions indicative of colonic spirochetosis.     

Comparison of flagellated and nonflagellated sperm in plants

Differences among flagellated and nonflagellated sperm in land plants are striking, but close examination reveals similarities in pattern of cytoskeleton and in nuclear structure. The microtubular cytoskeleton of flowering plant sperm consists of microtubule bundles arranged obliquely around the nucleus, terminating in cellular extensions. Microtubules are linked into bundles that branch and rejoin along the axis of the sperm cell, forming a cytoskeleton that determines cell shape but does not actively participate in cell movement. Generative cells and sperm share a pattern of microtubules not found in somatic cells. This pattern is initiated in the generative cell, one division before sperm formation, a situation parallel to spermatogenous cell development in vascular plants with flagellated sperm. Chromatin in flagellated and nonflagellated sperm is condensed by specialized histones.     

Metamorphosis of coeloblastula performed by multipotential larval flagellated cells in the calcareous sponge Leucosolenia laxa

The calcareous sponge Leucosolenia laxa releases free-swimming hollow larvae called coeloblastulae that are the characteristic larvae of the subclass Calcinea. Although the coeloblastula is a major type of sponge larva, our knowledge about its development is scanty. Detailed electron microscopic studies on the metamorphosis of the coeloblastula revealed that the larva consists of four types of cells: flagellated cells, bottle cells, vesicular cells, and free cells in a central cavity. The flagellated cells, the principal cell type of the larva, are arranged in a pseudostratified layer around a large central cavity. The larval flagellated cells characteristically have glutinous granules that are used as internal markers during metamorphosis. After a free-swimming period the larva settles on the substratum, and settlement apparently triggers the initiation of metamorphosis. The larval flagellated cells soon lose their flagellum and begin the process of dedifferentiation. Then the larva becomes a mass of dedifferentiated cells in which many autophagosomes are found. Within 18 h after settlement, the cells at the surface of the cell mass differentiate to pinacocytes. The cells beneath the pinacoderm differentiate to scleroblasts that form triradiate spicules. Finally, the cells of the inner cell mass differentiate to choanocytes and are arranged in a choanoderm that surrounds a newly formed large gastral cavity. We found glutinous granules in these three principal cell types of juvenile sponges, thus indicating the multipotency of the flagellated cells of the coeloblastula.     

Larval cells of sponge Halisarca dujardini (Demospongiae, Halisarcida). II. Some cell types marked by polyclonal antibodies

The recent morphological and experimental data concerning the involvement of flagellated cells in sponge larvae are contradictory and testify to or against the germinal layers inversion. A study of morphogenetic processes in sponges, in particular larval metamorphosis, is complicated by difficulties in identification and succession of certain cell types. It is possible to trace the destiny of flagellated and other larval cells by marking them with antibodies (AB) specified for each cell type. We separated larval and adult sponge cells of Halisarca dujardini in percoll density gradient and obtained polyclonal AB for the majority of these cell types. The protein pattern of larval flagellated cells differed significantly from that of other cell types. The major proteins of flagellated, collencyte-like and spherulous cells were used to raise the corresponding AB. Immunoblot showed all AB to be specific for certain proteins and suitable for immunofluorescence. The AB for flagellated cells reacted with the apical cytoplasm, but not with the flagellum, the AB for major protein of collencyte-like cells stained cytoplasm granules. The AB for spherulous cells of the adult sponge reacted with larval spherulous cells supposed to be of maternal origin. So, the method of cell marking with specific polyclonal AB can facilitate analysis of the layers inversion problem, as well as elucidate the degree of cell differentiation in larvae, their conformity to cells of the adult sponge or their provisional destiny.     

New clade of silicified bolidophytes that belong to Triparma (Bolidophyceae,Stramenopiles)

The small phytoplankton genus Triparma belongs to the class Bolidophyceae and contains two distinct forms: silicified species and naked flagellated species (formerly Bolidomonas). Recent studies showed that four silicified species/strains (Triparma laevis f. inornata, T. laevis f. longispina, T. strigata, and T. aff. verrucosa) belong to a single clade that is paraphyletic, because it also contains an unclassified flagellated strain, and is sister to a flagellated species, T. eleuthera. In this study, we isolated and characterized two new strains of silicified species to test the phylogenetic unity of silicified bolidophytes. The isolates were identified as T. retinervis strains because they possessed fine areolation on the cell wall. 18S rDNA and rbcL phylogenetic analyses demonstrated that T. retinervis formed a new silicified clade that is sister to the flagellated species T. pacifica. This reveals that there are at least two distinct clades including both silicified and flagellated Triparma species.     

The fate of larval flagellated cells during metamorphosis of the sponge Halisarca dujardini

Sponge larval flagellated cells have been known to form the external layer of larva, but their subsequent fate and morphogenetic role are still unclear. It is actually impossible to follow flagellated cell developmental fate unless a specific marker is found. We used percoll density gradient fractionation to separate different larval cell types of Halisarca dujardini (Demospongiae, Halisarcida). A total of 5 fractions were obtained which together contained all cell types. Fraction 1 contained about 100% FC and its polypeptide composition was very different to that of the other fractions. Of all larval cell types, flagellated cells displayed the lowest in vitro aggregation capacity. We raised a polyclonal antibody against a 68 kDa protein expressed by larval flagellated cells. Its specificity was tested on total protein extract from adult sponges by Western blotting and proved to be suitable for immunofluorescence. By means of double immunofluorescence using both this polyclonal antibody and commercial anti-tubulin antibodies, we studied the distribution of the 68 kDa protein in larval flagellated cells and its fate at successive stages of metamorphosis. In juvenile sponges just after metamorphosis the choanocytes and the upper pinacoderm were labelled with both antibodies. In larval flagellated cells, the 68 kDa protein was found all over the cytoplasm appearing as granules, while in adult sponges, it was present in the apical part of choanocytes in the vicinity of collars. Direct participation of the larval flagellated cells in the development of definitive structures was demonstrated.     

Novel protein from larval sponge cells,ilborin, is related to energy turnover and calcium binding and is conserved among marine invertebrates

Sponges (phylum Porifera) are early-branching animals, whose outwardly simple body plan is underlain by a complex genetic repertoire. The transition from a mobile larva to an attached filter-feeding organism occurs by metamorphosis, a process accompanied by a radical change of the body plan and cell transdifferentiation. The continuity between larval cells and adult tissues is still obscure. In a previous study, we have produced polyclonal antibodies against the major protein of the flagellated cells covering the larva of the sponge Halisarca dujardini, used them to trace the fate of these cells and shown that the larval flagellated cells transdifferentiate into the choanocytes. In the present work, we identified the sequence of this novel protein, which we named ilborin. A search in the open databases showed that multiple orthologues of the newly identified protein are present in sponges, cnidarians, flatworms, ctenophores and echinoderms, but none of them has been described yet. Ilborin has two conserved domains: triosephosphate isomerase-barrel, which has enzymatic activity against macroergic compounds, and canonical EF-hand, which binds calcium. mRNA of ilborin is expressed in the larval flagellated cells. We suggest that the new protein is involved in the calcium-mediated regulation of energy metabolism, whose activation precedes metamorphosis.     

Population Size,Clones and Morphogenesis in Naegleria gruberi*

SYNOPSIS. The size of the population of Naegleria gruberi at the time the amoebae are offered the opportunity to become flagellated is not a critical factor in the morphogenesis of this organism. Small populations (1-15 cells) readily become flagellated. Small populations (1-5 cells) washed several times also become flagellated. Clonal populations (25) have been established. All clones yield flagellates under the usual conditions. It is suggested that the physiological state of the amoebae is a factor in determining the number of cells that will undergo morphogenesis at any given time.     

Effect of Viscosity on Bacterial Motility

The behavior of a number of motile flagellated bacteria toward viscosity characteristics of their fluid environments was observed. All showed an increase in velocity (micrometers per second) in more viscous solutions. Velocity reached a maximum at a characteristic value, however, and thereafter decreased with higher viscosities. Peritrichously flagellated bacteria had maximum velocities at higher viscosities than polarly flagellated bacteria. Effects of temperature, and possible utilization of chemical constituents in the viscous solutions, were studied and found to be negligible factors under the experimental conditions used. Different agents produced the same phenomenon, thus indicating that there probably were no chemically induced metabolic effects. Loss of available water and the possibility of a variable energy supply to the flagellar propulsive system were considered but are believed minimal. Theoretically derived thermodynamic equations were utilized and suggest that the conformation of the flagellar helix affects efficiency of propulsion. Such a relationship between helix waveform and velocity was experimentally observed with Thiospirillum jenese.     

Bau und Funktion des Süßwasserschwamms Ephydatia fluviatilis L. (Porifera)

Zusammenfassung Die Kragengeißelkammern von Ephydatia fluviatilis entstehen frei im Mesenchym. An den Entstehungsorten trifft man auf Anhäufungen rundlicher Zellen, die allem Anschein nach von Archäocyten stammen, jedoch kleiner sind als diese und einen nukleoluslosen Kern besitzen. Hierbei handelt es sich um Choanoblasten, die zunächst eine Geißel, später den Kragen ausbilden und sich als Choanocyten zu Kragengeißelkammern zusammenfügen.Die im Mesenchym vorläufig fertiggestellten Kragengeißelkammern gelangen an das Endopinacocytenepithel des ausführenden Kanalysystems. Daraufhin bilden sich die tangierten Choanocyten zu Konuszellen um. Das Endopinacocytenepithel antwortet seinerseits mit der Ausbildung einer Poruszelle pro Kragengeißelkammer. Die Porocyten gehen mittels der konfrontierten Konuszellen dauerhafte Verbindungen mit den zugehörigen, nunmehr funktionstüchtigen Kragengeißelkammern ein.

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Structure and function of the fresh-water sponge Ephydatia fluviatilis L. (Porifera)VIII. The origin and development of the flagellated Chambers and their junction with the excurrent canal system

Summary The flagellated chambers of Ephydatia fluviatilis arise at scattered sites within the mesenchyme. Each such site is marked by an accumulation of rounded cells, which appear to be derived from archaeocytes in most respects except that they are smaller than the latter and have no nucleoli in the nucleus. These are choanoblasts, which first develop a flagellum and later a collar; eventually, as choanocytes, they become arranged so as to form a flagellated chamber.Having reached this preliminary stage of completion in the mesenchyme, the flagellated chambers migrate to the endopinacocyte epithelium of the excurrent canal system. Then the choanocytes at the contact point are converted to cone cells. The endopinacocyte epithelium in turn responds by developing one pore cell for each flagellated chamber. The porocytes become permanently joined to the chamber by way of the adjacent cone cells, and from this time on the flagellated chamber is functional.

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Abkürzungen A Archäocyte - aK ausführender Kanal - B Bakterien - Ch Choanocyte - eK einführender Kanal - G Geißel - GK Kragengeißelkammer - GK-A Anlage von Kragengeißelkammern - K Zellkern - Kr Kragen - KZ Konuszelle - M Mesenchym - N SiO₂-Nadel - PC Endopinacocyten - PD Pinacoderm - PV pulsierende Vakuole - PZ Porenzelle - S Gemmulaschale - Sk Skleroblast - Sp Spongin - SR Subdermalraum     

Differential localization of membrane receptor chemotaxis proteins in the Caulobacter predivisional cell

The methyl-accepting chemotaxis proteins (MCPs) are membrane receptors that initiate signal transduction to the flagellar rotor upon ligand binding. The synthesis of these proteins occurs only in the Caulobacter crescentus predivisional cell coincident with the biosynthesis of the polar flagellum. Both the flagellum and the MCPs are partitioned to only one daughter cell, the swarmer cell, upon division. We report the results of experiments designed to determine the distribution of these MCPs within swarmer cells and predivisional cells. Flagellated and non-flagellated vesicles were prepared from these cells by immunoaffinity chromatography and the level of MCPs that had been labeled either in vivo or in vitro with methyl-3H was determined. Small membrane vesicles from swarmer cells contained [methyl-3H]MCPs both in the flagellated and non-flagellated vesicles, which indicates that the region immediately surrounding the flagellum, as well as the rest of the surface of the swarmer cell, contains [methyl-3H]MCP. Thus, the MCPs are not specifically localized to the immediate vicinity of the flagellar rotor. The distribution of MCPs was examined in flagellated and non-flagellated vesicles isolated from predivisional cells. The analysis of small predivisional vesicles showed that the MCP content is higher in the flagellated vesicles, and analysis of large flagellated vesicles showed that the MCPs are positioned preferentially in the swarmer cell portion of the predivisional cell. This positional bias of MCPs within predivisional cells could reflect either a large compartment or membrane domain within the incipient swarmer cell, or a gradient of MCPs, with the highest concentration in the vicinity of the flagellum.     

Ectothiorhodospira halophila: A new species of the genus Ectothiorhodospira

Summary A halophilic purple sulfur spirillum, previously reported by the authors and called SL-1, has been characterized as a new species of the genus Ectothiorhodospira, E. halophila. The organism can grow in media containing from 9% NaCl to 30% NaCl. It needs no vitamins. Succinate or acetate can be used as hydrogen donors, but a reduced sulfur source is necessary for growth. The temperature optimum is 47°C. The cells are bipolarly flagellated, not monopolarly flagellated as previously reported.     

Taxonomy of Aerobic Marine Eubacteria

Two hundred and eighteen strains of nonfermentative marine bacteria were submitted to an extensive morphological, physiological, and nutritional characterization. All the strains were gram-negative, straight or curved rods which were motile by means of polar or peritrichous flagella. A wide variety of organic substrates served as sole sources of carbon and energy. The strains differed extensively in their nutritional versatility, being able to utilize from 11 to 85 carbon compounds. Some strains had an extracellular amylase, gelatinase, lipase, or chitinase and were able to utilize n-hexadecane and to denitrify. None of the strains had a yellow, cell-associated pigment or a constitutive arginine dihydrolase system, nor were they able to hydrolyze cellulose or agar. The results of the physiological and nutritional characterization were submitted to a numerical analysis which clustered the strains into 22 groups on the basis of phenotypic similarities. The majority of these groups were separable by a large number of unrelated phenotypic traits. Analysis of the moles per cent guanine plus cytosine (GC) content in the deoxyribonucleic acid of representative strains indicated that the peritrichously flagellated groups had a GC content of 53.7 to 67.8 moles%; polarly flagellated strains had a GC content of 30.5 to 64.7 moles%. The peritrichously flagellated groups were assigned to the genus Alcaligenes. The polarly flagellated groups, which had a GC content of 43.2 to 48.0 moles%, were placed into a newly created genus, Alteromonas; groups which had a GC content of 57.8 to 64.7 moles% were placed into the genus Pseudomonas; and the remaining groups were left unassigned. Twelve groups were given the following designations: Alteromonas communis, A. vaga, A. macleodii, A. marinopraesens, Pseudomonas doudoroffi, P. marina, P. nautica, Alcaligenes pacificus, A. cupidus, A. venustus, and A. aestus. The problems of assigning species of aerobic marine bacteria to genera are discussed.     

Experimental metamorphosis of Halisarca dujardini larvae (Demospongiae, Halisarcida): evidence of flagellated cell totipotentiality

The potency of flagellated cells of Halisarca dujardini (Halisarcida, Demospongiae) larvae from the White Sea (Arctic) was investigated experimentally during metamorphosis. Two types of experiments were conducted. First, larvae were maintained in Ca2+ free seawater (CFSW) until the internal cells were released outside through the opening of the posterior pole. These larvae that only composed of flagellated cells (epithelial larvae) were then returned to sea water (SW) to observe their metamorphosis. The posterior aperture closed before they settled on a substratum and started a metamorphosis similar to intact larvae. Secondly, epithelial larvae were, first, further treated in CFSW and then mechanically dissociated. Separated cells or groups of cells were returned to SW, where they constituted large friable conglomerates. After 12-17 h in SW, flagellated cells showed the first steps of dedifferentiation, and regional differentiation was noticeable within conglomerates after approximately 24-36 h. External cells differentiated into pinacocytes while internal cells kept their flagella and became united in a layer. Within 48-72 h, internal cells of the conglomerates formed spherical or ovoid clusters with an internal cavity bearing flagella. These clusters further fused together in a rhagon containing one or two large choanocyte chambers. The sequence of cellular processes in epithelial larvae and in flagellated cell conglomerates was similar. Previous observations indicating the totipotentiality of larval flagellated cells during normal metamorphosis of H. dujardini are thus confirmed.