Molekulare Propeller: Bakteriengeißeln und ihr Antrieb

Schmitt, Rüdiger

doi:10.1002/biuz.960270116

Cited by 3 publications

(3 citation statements)

References 12 publications

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“…It has been shown that swimming S. meliloti cells respond to tactic stimuli by modulating their flagellar rotary speed (37) and that two novel motor proteins may be essential players in speed control (27). Hence, directional changes in the tracks of swimming S. meliloti cells-imperative for any chemotactic response-are a consequence of individual flagella rotating at different speeds (31). It thus appears that complex flagellar filaments and the new mode of directional control of swimming cells have evolved in response to the specific condition of swimming in viscous fluids prevailing in the soil biotope.…”

mentioning

confidence: 99%

Mutational Analysis of the Rhizobium lupini H13-3 and Sinorhizobium meliloti Flagellin Genes: Importance of Flagellin A for Flagellar Filament Structure and Transcriptional Regulation

Scharf

Schuster-Wolff-Bühring

Rachel

et al. 2001

J Bacteriol

103

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Motile bacteria are propelled by helical flagellar filaments connected by a proximal hook to the basal body holding the flagellar rotary motor (for reviews, see references 1, 20, and 41). Traditionally, flagellar filaments are classified by their electron microscopical appearance into two types, named plain and complex (22,33). The plain filaments of Escherichia coli and Salmonella spp. have a smooth surface structure with faint striations, whereas the complex filaments of soil bacteria, like Rhizobium lupini H13-3 and Sinorhizobium meliloti, exhibit a prominent helical pattern of alternating ridges and grooves (16,32,38). Unlike the flexible plain filaments, which are capable of switching from left-handed to right-handed helicity (21), the complex filaments are more rigid and do not switch handedness. Pairwise helical perturbations result in a subunit composed of a dimer of flagellin (39). Interflagellin bonds are believed to lock the complex filament in a rigid, right-handed helical conformation suitable for propulsion in viscous media (4, 8). Concomitantly, the flagellar motor of Rhizobium rotates entirely clockwise and does not reverse its sense of rotation (9). It has been shown that swimming S. meliloti cells respond to tactic stimuli by modulating their flagellar rotary speed (37) and that two novel motor proteins may be essential players in speed control (27). Hence, directional changes in the tracks of swimming S. meliloti cells-imperative for any chemotactic response-are a consequence of individual flagella rotating at different speeds (31). It thus appears that complex flagellar filaments and the new mode of directional control of swimming cells have evolved in response to the specific condition of swimming in viscous fluids prevailing in the soil biotope.The flagellar filament consists of an assembly of about 20,000 flagellin subunits, whose molecular mass typically ranges from 40 to 60 kDa (20). Flagellins are three-domain proteins, with the N-and C-terminal domains being responsible for the quarternary interactions between subunits and the central, surfaceexposed domain performing no obvious structural role but containing all of the potent antigenic epitopes. We have previously shown that the S. meliloti genome contains four genes, flaA, flaB, flaC, and flaD, encoding four related flagellin subunits (28, 36), and we report here three flagellin genes, flaA, flaB, and flaD, as constituents of the R. lupini H13-3 flagellar regulon. The latter strain was chosen because the first 13-Å-resolution, three-dimensional density map has been generated from its complex filament using low-dose electron micrographs of negatively stained specimens (4). This constellation may provide specific handles for future sequence-structure analysis.In an effort to understand the process of assembling the complex filaments of the related soil bacteria R. lupini H13-3 and S. meliloti and to elucidate the contribution of single subunits to the filament structure, we have taken a genetic approach. Mutational analyses revealed th...

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confidence: 99%

Mutational Analysis of the Rhizobium lupini H13-3 and Sinorhizobium meliloti Flagellin Genes: Importance of Flagellin A for Flagellar Filament Structure and Transcriptional Regulation

Scharf

Schuster-Wolff-Bühring

Rachel

et al. 2001

J Bacteriol

103

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“…The phenomenon of living at high altitudes has been discussed and dealt with in different approaches in De Lattin’s [ 38 ] chapter on the Oriental region. More recently, the interlocking of Oriental and Palearctic distribution areas was analyzed within the context of Odonata [ 39 ] and Raphidioptera (Inocelliidae) [ 40 , 41 ]. The main argument and justification for this interpretation is the fact of their present-day occurrence at high altitudes.…”

Section: Discussionmentioning

confidence: 99%

Mining the Species Diversity of Lacewings: New Species of the Pleasing Lacewing Genus Dilar Rambur, 1838 (Neuroptera, Dilaridae) from the Oriental Region

Aspöck

et al. 2021

Insects

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The species diversity of insects is extraordinarily rich, but still has been insufficiently explored or underestimated particularly for uncommon groups. The pleasing lacewings (Dilaridae) are a little known family of Neuroptera with distinct sexually dimorphic antennae. The species diversity of pleasing lacewings was recently found to be severely underestimated and requires a comprehensive investigation, as well as systematic reviews. Here, we report on 12 new species of the pleasing lacewing genus Dilar Rambur, 1838, from the Oriental region, namely D. forcipatus sp. nov. and D. laoticus sp. nov. from Laos (new country record of Dilar); D. malickyi sp. nov., D. phraenus sp. nov. and D. rauschorum sp. nov. from northern Thailand; D. striatus sp. nov. from northern Vietnam; D. cangyuanensis sp. nov., D. daweishanensis sp. nov., D. nujianganus sp. nov., D. weibaoshanensis sp. nov., D. yucheni sp. nov., and D. zhangweiae sp. nov. from Yunnan and Tibet, both in southwestern China. The new species of Dilar display several types of wing marking patterns, and the morphology of the male genitalia is highly diverse. A comprehensive examination of the species diversity and distribution of Dilar concluded that Yunnan (southwestern China) represents a biogeographic region with high endemism and the richest species diversity. The potential correlation between vertical distribution and geographical latitude in Dilar was also analyzed.

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“…With their recurrent periods of glacial advances and retreats, the Pleistocene glacial cycles are considered one of the most important drivers of current distributional patterns and patterns of genetic diversity in animals and plants [ 1 , 2 , 3 ]. This particularly applies to arctic-alpine taxa, which are characterized by a disjunct occurrence in two geographically distant areas, the subarctic to arctic plains and hills, and the high mountain ranges of the Alps and/or other Eurasian mountains [ 4 ]. This large-scale disjunction occurs in numerous species of plants and animals, typically taxa that are characterized by poor dispersal capacity [ 1 , 5 , 6 , 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps

Paill

Koblmüller

Friess³

et al. 2021

Insects

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The last ice age considerably influenced distribution patterns of extant species of plants and animals, with some of them now inhabiting disjunct areas in the subarctic/arctic and alpine regions. This arctic-alpine distribution is characteristic for many cold-adapted species with a limited dispersal ability and can be found in many invertebrate taxa, including ground beetles. The ground beetle Pterostichus adstrictus Eschscholtz, 1823 of the subgenus Bothriopterus was previously known to have a holarctic-circumpolar distribution, in Europe reaching its southern borders in Wales and southern Scandinavia. Here, we report the first findings of this species from the Austrian Ötztal Alps, representing also the southernmost edge of its currently known distribution, confirmed by the comparison of morphological characters to other Bothriopterus species and DNA barcoding data. Molecular data revealed a separation of the Austrian and Finish specimens with limited to no gene flow at all. Furthermore, we present the first data on habitat preference and seasonality of P. adstrictus in the Austrian Alps.

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Molekulare Propeller: Bakteriengeißeln und ihr Antrieb

Cited by 3 publications

References 12 publications

Mutational Analysis of the Rhizobium lupini H13-3 and Sinorhizobium meliloti Flagellin Genes: Importance of Flagellin A for Flagellar Filament Structure and Transcriptional Regulation

Mutational Analysis of the Rhizobium lupini H13-3 and Sinorhizobium meliloti Flagellin Genes: Importance of Flagellin A for Flagellar Filament Structure and Transcriptional Regulation

Mining the Species Diversity of Lacewings: New Species of the Pleasing Lacewing Genus Dilar Rambur, 1838 (Neuroptera, Dilaridae) from the Oriental Region

Relicts from Glacial Times: The Ground Beetle Pterostichus adstrictus Eschscholtz, 1823 (Coleoptera: Carabidae) in the Austrian Alps

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