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PubMedDate not supplied

Andalucia (n. gen.)--the deepest branch within jakobids (Jakobida; Excavata), based on morphological and molecular study of a new flagellate from soil.

A new heterotrophic flagellate (Andalucia godoyi n. gen. n. sp.) is described from soil. Earlier preliminary 18S rRNA analyses had indicated a relationship with the phylogenetically difficult-to-place jakobid Jakoba incarcerata. Andalucia godoyi is a small (3-5 mum) biflagellated cell with a ventral feeding groove. It has tubular mitochondrial cristae. There are two major microtubular roots (R1, R2) and a singlet root associated with basal body 1 (posterior). The microtubular root R1 is associated with non-microtubular fibres "I,""B," and "A," and divides in two parts, while R2 is associated with a "C" fibre. These structures support the anterior portion of the groove. Several features of A. godoyi are characteristic of jakobids: (i) there is a single dorsal vane on flagellum 2; (ii) the C fibre has the jakobid multilaminate substructure; (iii) the dorsal fan of microtubules originates in very close association with basal body 2; and (iv) there is no "R4" microtubular root associated with basal body 2. Morphological analyses incorporating the A. godoyi data strongly support the monophyly of all jakobids. Our 18S rRNA phylogenies place A. godoyi and J. incarcerata as a strong clade, which falls separately from other jakobids. Statistical tests do not reject jakobid monophyly, but a specific relationship between Jakoba libera and J. incarcerata and/or A. godoyi is rejected. Therefore, we have established a new genus Andalucia n. gen. with the type species Andalucia godoyi n. sp., and transfer Jakoba incarcerata to Andalucia as Andalucia incarcerata n. comb.

Animals↗
PubMed1987

Sensory transduction in flagellate bacteria.

Flagellate bacteria can respond to a wide range of environmental chemicals and a variety of physical parameters, and integrate those responses. The most important thing for a cell is to maintain its energy level; bacteria therefore respond directly to any changes in their PMF. This has been likened to higher organisms responding to a physiological change, for example, a fall in blood glucose. In addition, if the PMF is high, the cell is free to respond to a limited range of metabolites and possibly move to an area that will allow an increased growth rate. Bacteria do not sense all amino acids, as the space available on the cytoplasmic membrane is limited, and a change in a few important metabolites is probably a good measure of the general environment around the cell. The sensory response does not require either transport into the cell or metabolism of the chemical, only the binding to the specific MCP. The cell could have a mutation in the pathway metabolizing the chemoeffector, but it would still respond to changes in the concentration of that compound. This taken with the ability of the cells to adapt to the stimulus has been considered to be the prokaryotic equivalent of smell and taste.

Bacterial Physiological Phenomena↗
PubMed1970

Transformation of Tetramitus amebae into flagellates.

Methods have beeni developed for controlling the transformation of Tetramitus rostratus, a protozoan able to reproduce either as an ameba or as a flagellate. An essential conidition for transformation is a low concentration of oxygen in the environment.

Culture Media↗
PubMed1980

Inhibition of growth and purine-metabolizing enzymes of trypanosomid flagellates by N6-methyladenine.

N6-methyladenine (6-methylaminopurine [6-MA]), a plant growth regulator and a normal constituent of nucleic acids, has been found to inhibit the growth of Trypanosoma cruzi, Leishmania braziliensis, L. donovani, L. tarentolae, L. mexicana, and Crithidia fasciculata. The extent of growth inhibition in these organisms is related to the sensitivity of guanine deaminase (guanine aminohydrolase, EC 3.5.4.3), adenine deaminase (adenine aminohydrolase, EC 3.5.4.2), and adenosine hydrolase and phosphorylase. 6-MA was not an inhibitor of the purine phosphoribosyltransferases. Of the trypanosomid flagellates tested. Trypanosoma cruzi was most susceptible to 6-MA. Neither adenine deaminase (as found in the leishmaniae and C. fasciculata) nor adenosine deaminase (as found in mammalian cells) could be demonstrated in T. cruzi. Guanine deaminase, which is strikingly inhibited by 6-MA in T. cruzi, appears to play a major role in the purine salvage pathway of this organism, as judged from growth experiments and enzyme inhibition studies. Enzyme sensitivities to 6-MA vary greatly depending upon the organism. Rabbit liver guanine deaminase was shown to be insensitive to 6-MA at the concentrations used in this study.

Adenine↗
PubMed1997

The alternative sigma factor sigma28 of Legionella pneumophila restores flagellation and motility to an Escherichia coli fliA mutant.

Gene expression in Legionella pneumophila, the etiological agent of Legionnaires' disease, can be controlled by alternative forms of RNA polymerase programmed by distinct sigma factors. To understand the regulation of L. pneumophila flagellin expression, we cloned the sigma factor (FliA) of RNA polymerase responsible for the transcription of the flagellin gene, flaA. FliA is a member of the sigma28 class of alternative sigma factors identified in several bacterial genera. The gene fliA has been isolated from an expression library of L. pneumophila isolate Corby in Escherichia coli K-12. This library was transformed into a fliA mutant of E. coli K-12 containing a plasmid carrying the L. pneumophila-specific flaA promoter fused to the reporter gene luxAB. Screening the obtained transformants for luciferase activity, we isolated the major part of the fliA gene on a 1.64-kb fragment. This fragment was sequenced and used for reverse PCR in order to recover the complete fliA gene. The resulting 1.03-kb fragment was shown to contain the entire fliA gene. L. pneumophila FliA has 55 and 43% amino acid identity with the homologous sequences of Pseudomonas aeruginosa and E. coli. Furthermore, the L. pneumophila fliA gene was able to restore the flagellation and the motility defect of an E. coli fliA mutant. This result suggests that the L. pneumophila sigma28 protein can bind to the E. coli core RNA polymerase to direct transcription initiation from the flaA-specific promoter.

Amino Acid Sequence↗
PubMed2005

Magnesium promotes flagellation of Vibrio fischeri.

The bacterium Vibrio fischeri requires bacterial motility to initiate colonization of the Hawaiian squid Euprymna scolopes. Once colonized, however, the bacterial population becomes largely unflagellated. To understand environmental influences on V. fischeri motility, we investigated migration of this organism in tryptone-based soft agar media supplemented with different salts. We found that optimal migration required divalent cations and, in particular, Mg2+. At concentrations naturally present in seawater, Mg2+ improved migration without altering the growth rate of the cells. Transmission electron microscopy and Western blot experiments suggested that Mg2+ addition enhanced flagellation, at least in part through an effect on the steady-state levels of flagellin protein.

Agar↗
PubMed1967

Genetic control of flagellation in Bacillus subtilis.

Flagellation in Bacillus subtilis was shown to involve at least three loci: a gene H controlling the specificity of the flagellar antigen; a gene fla controlling the presence or absence of flagella; and a gene mot controlling the function of the flagella. The loci were shown to be nonallelic and unlinked in transformation tests. Strains W 23 and SB 108-b, a derivative of strain 168, were shown to differ in their major flagellar antigen.

Antigens↗
PubMed1993

Use of monoclonal antibodies to distinguish pathogenic Naegleria fowleri (cysts, trophozoites, or flagellate forms) from other Naegleria species.

Monoclonal antibodies (MAbs) reactive to the pathogenic amoeba Naegleria fowleri were analyzed by enzyme-linked immunosorbent assay (ELISA), indirect immunofluorescence assay, Western blotting (immunoblotting), and radioimmunoprecipitation assay (RIPA). Two MAbs (3A4 and 5D12) showed reactivity by ELISA with all N. fowleri strains tested and no reactivity with the five other Naegleria species, N. lovaniensis, N. gruberi, N. australiensis, N. jadini, and N. andersoni. These MAbs reacted with the three morphological forms of N. fowleri (trophozoites, cysts, and flagellates). The reactivity on Western blots was suppressed by treatment with metaperiodate, suggesting a carbohydrate epitope. Differences in reactivity patterns between trophozoites and cysts observed with radioimmunoprecipitation assay might reflect differences in biological properties. The formalin stability of the epitope may be useful in detecting N. fowleri in fixed biopsies and in investigating the pathological process.

Animals↗
PubMed1982

Attachment of the flagellate Giardia lamblia: role of reducing agents, serum, temperature, and ionic composition.

The flagellated protozoan Giardia lamblia has been grown only in highly complex media under reduced oxygen tension. Therefore, the organic and physiological requirements for in vitro attachment and short-term (12-h) survival of this organism were determined. In defined maintenance media, a thiol reducing agent (e.g., cysteine) was absolutely required for attachment and survival of this aerotolerant anaerobe. The crude bovine serum Cohn III fraction greatly stimulated attachment and survival. Attachment was decreased at a reduced temperature (24 degrees C as compared with 35.5 degrees C) and absent at 12 degrees C or below. Attachment and survival were strongly dependent upon pH and ionic strength, with optima at pH 6.85 to 7.0 and 200 to 300 mosmol/kg. Sodium chloride was better tolerated than KC1. Reduction of Ca2+ and Mg2+ to below 10(-8) M did not significantly affect attachment.

Animals↗
PubMed1973

Non-flagellate Pseudomonas aeruginosa in pathological material.

Three isolates of non-flagellate Pseudomonas aeruginosa obtained from pathological material of human cases are described. Two were found in urinary tract infections and the third in a respiratory infection. They were shown by typing methods to be distinct strains.

Aged↗
PubMed1974

Further isolations of non-flagellate Pseudomonas aeruginosa.

Three strains of non-flagellate Ps. aeruginosa isolated from pathological specimens have already been described. The purpose of this paper is to report further isolates. All strains have been shown to be different types isolated from a variety of infections.

Cell Movement↗
PubMed1981

Intestinal and urogenital flagellates.

Although the human alimentary and urogenital tracts are parasitized by seven species of flagellate protozoa [115], only two, Giardia lamblia and Trichomonas vaginalis, are generally considered to be pathogens. This review, therefore, concentrates on these organisms and in particular on the experimental and clinical chemotherapy of trichomoniasis and giardiasis. Due to the limited space and the availability of excellent recently published reviews, topics such as life cycles, epidemiology, prevalence and pathology are only briefly discussed in the sections entitled 'Biological Aspects'. The reader seeking comprehensive reference lists and more information on Trichomonas and Giardia and the diseases they cause is referred to these reviews.

Animals↗
PubMed1976

Rotary movements and fluid membranes in termite flagellates.

We previously described a remarkable type of cell motility that provided direct, visual evidence for the fluid nature of cell membranes. The movement involved continual, unidirectional rotation of one part of a protozoan, including the plasma membrane and cytoplasmic organelles, in relation to a neighbouring part. The cell membrane in the 'shear zone' appeared continuous with that of the rest of the cell. The rotary motor consisted, at least in part, of a non-contractile, microtubular axostyle which extended centrally through the cell. The protozoan was a devescovinid flagellate found in the hindgut of a Florida termite. In this paper, we have confirmed earlier reports of this type of motility in other kinds of devescovinids from Australian termites. By demonstrating continuity of the plasma membrane in the shear zone of the Australian devescovinids as well, we have obtained additional examples that provide direct, visual evidence for fluid membranes. A comparative analysis of rotational motility in various devescovinids revealed 2 different kinds of rotary mechanisms. Hyperdevescovina probably have an internal motor, in which one part of the cell exerts forces against another part, as in the Florida termite devescovinid. Devescovina species, on the other hand, have an external motor, in which flagellar and/or papillar movements exert forces against the surrounding medium. The structure of the axostyle in different devescovinids was compared, and its role in rotational motility discussed with respect to the behavioural data.

Animals↗
PubMed1980

Origin and development of free kinetosomes in the flagellates Deltotrichonympha and Koruga.

The formation of more than half a million free (non-flagellated) kinetosomes in post-mitotic Deltotrichonympha and Koruga from Mastotermes is described. Ladder-like configurations of prokinetosomes extend from the 2 fibrous walls of the centriolar apparatus in the rostrum. The prokinetosomes within the ladders are arranged side by side in 2 layers. Because the fibrous walls are oriented perpendicular to each other, the 2 groups of prokinetosomal ladders are also mutually perpendicular. The prokinetosomes arise continuously next to the fibrous walls, and migrate outward along the ladders as they develop. Consequently, progressive stages in kinetosome formation occur sequentially along the ladders in a polarized fashion. A cartwheel-structure appears first. This is followed by the formation of A tubules, B tubules and C tubules in an orderly sequence around the cartwheel (counter-clockwise, viewed from the distal end). The cartwheel ring disappears after the triplets have formed. The new free kinetosomes accumulate in a disorganized mass at the ends of the ladders. Later, the kinetosomes become organized end to end into the polarized chains found in interphase cells. The fibrous wall of the centriolar apparatus is thus a new type of intermediate structure associated with the mass production of basal bodies. It appears to determine the spatial organization of the 'assembly lines' of developing kinetosomes.

Animals↗
PubMedDate not supplied

The Glu-modification of alpha-tubulin in the feeding apparatus of the primitive flagellate Entosiphon sulcatum is only apparent after detergent treatment.

Using specific monoclonal antibodies, we investigated the distribution of post-translational modified Tyr- and Glu-tubulins during interphase of the primitive flagellate Entosiphon sulcatum. Immunofluorescence studies of simultaneously permeabilized and fixed cells revealed that microtubular structures comprising Ca(2+)-labile subpellicular and flagellar MTs and Ca(2+)-stable MTs in the siphon complex (feeding organelle) reacted surprisingly unorthodox with antibodies against Tyr- and Glu-tubulin: Unexpectedly, the siphon complex consisting of Ca(2+)-stable MTs appeared exclusively Tyr-positive, whereas the Ca(2+)-labile subpellicular and flagellar MTs reacted with the Glu- as well as with the Tyr-antibody. That the siphon MTs were indeed Ca(2+)-stable and all other MTs had become solubilized, was verified by EM-observation. This surprising result contrasting considerably with the permanent nature of the siphon complex, was reconsidered after preceding lysis and extraction procedures. Depending on the type of detergent used and on extraction times applied, the MTs of the siphon complex now always showed also Glu-positivity, indicating the presence of detyrosinated alpha-tubulin as a biochemical marker of stabilized MTs. Since saponin, irrespective of subsequent extraction times, always produced a Glu-positive reaction and ultrastructural analysis never gave compelling evidence for a drastic MAP-removal, we conclude that the Glu-epitope became freely accessible due to conformational changes in the tubulin polymeres.

Animals↗
PubMed2005

A fluid-dynamic interpretation of the asymmetric motion of singly flagellated bacteria swimming close to a boundary.

The singly flagellated bacterium, Vibrio alginolyticus, moves forward and backward by alternating the rotational direction of its flagellum. The bacterium has been observed retracing a previous path almost exactly and swimming in a zigzag pattern. In the presence of a boundary, however, the motion changes significantly, to something closer to a circular trajectory. Additionally, when the cell swims close to a wall, the forward and backward speeds differ noticeably. This study details a boundary element model for the motion of a bacterium swimming near a rigid boundary and the results of numerical analyses conducted using this model. The results reveal that bacterium motion is apparently influenced by pitch angle, i.e., the angle between the boundary and the swimming direction, and that forward motion is more stable than backward motion with respect to pitching of the bacterium. From these results, a set of diagrammatic representations have been created that explain the observed asymmetry in trajectory and speed between the forward and backward motions. For forward motion, a cell moving parallel to the boundary will maintain this trajectory. However, for backward motion, the resulting trajectory depends upon whether the bacterium is approaching or departing the boundary. Fluid-dynamic interactions between the flagellum and the boundary vary with cell orientation and cause peculiarities in the resulting trajectories.

Biological Clocks↗
PubMed2003

Screening effect diverts the swimming directions from diaphototactic to positive phototactic in a disk-shaped green flagellate Mesostigma viride.

We found diaphototactic behavior (i.e. the cells swim perpendicularly with respect to the incident light) in a strain with colorless eyespot of a unicellular disk-shaped green flagellate Mesostigma viride. Lacking pigments completely in the eyespot, the screening effect in this strain was due only to the central part of the chloroplast whose cross section was thin. The diaphototaxis was most obvious when unilateral green stimulus light (520-580 nm) was given, whereas positive phototaxis appeared when given blue light (430-490 nm). The choice between diaphototaxis and (ordinary) phototaxis depended entirely on the transmission (%T) of the cell body against each wavelength of the stimulus: the green light penetrated well (%T > 90%), whereas the blue light was considerably shaded by the chloroplast (50% < %T < 70%). The fraction of positive phototactically behaving cells against each wavelength was in proportion to the front-to-back contrast value obtained at each individual wavelength. The fraction of diaphototaxis was inversely proportional to it. In addition, bilateral stimulus irradiations to wild-type cell with colored eyespot provided useful information about the principle of the diaphototactic steering.

Animals↗
PubMedDate not supplied

Heterologous expression of photoactivated adenylyl cyclase (PAC) genes from the flagellate Euglena gracilis in insect cells.

The unicellular, green flagellate wild-type Euglena gracilis (strain Z) possesses two genes of the photoactivated adenylyl cyclase (PAC) family. The corresponding gene products were found to be responsible for step-up (but not step-down) photophobic responses as well as both positive and negative phototaxis. The proteins consist of two PACalpha (Mr 105 kDa) and two PACbeta (90 kDa) subunits. In an effort to produce sufficient amounts of PAC proteins, several routes of over-expression have been tried including homologous expression in Euglena and heterologous expression in Escherichia coli. All these approaches were hampered by low yield or formation of inclusion bodies. Therefore we decided to attempt a heterologous expression in an insect cell line. PACalpha and PACbeta were separately cloned in the transfer vector pBacPAK9 with a His tag attached. The transfer vector was subsequently cotransfected via baculovirus into the insect cells and amplified. For the expression both recombinant viruses (containing PACbeta and PACbeta, respectively) were cotransfected simultaneously into insect cells. The expressed proteins were analyzed in Western blots using PACalpha and PACbeta antibodies. Most of the proteins were found to be in soluble form in high yield. The recombinant PAC proteins were purified via their attached His tag on an anti-His resin. Adenylyl cyclase activity was quantified after blue-light excitation using a cAMP enzyme immunoassay kit.

Adenylyl Cyclases↗