Journal articles on the topic 'Type IV filament'
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Braun, Tatjana, Matthijn R. Vos, Nir Kalisman, Nicholas E. Sherman, Reinhard Rachel, Reinhard Wirth, Gunnar F. Schröder, and Edward H. Egelman. "Archaeal flagellin combines a bacterial type IV pilin domain with an Ig-like domain." Proceedings of the National Academy of Sciences 113, no. 37 (August 30, 2016): 10352–57. http://dx.doi.org/10.1073/pnas.1607756113.
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The bacterial flagellar apparatus, which involves ∼40 different proteins, has been a model system for understanding motility and chemotaxis. The bacterial flagellar filament, largely composed of a single protein, flagellin, has been a model for understanding protein assembly. This system has no homology to the eukaryotic flagellum, in which the filament alone, composed of a microtubule-based axoneme, contains more than 400 different proteins. The archaeal flagellar system is simpler still, in some cases having ∼13 different proteins with a single flagellar filament protein. The archaeal flagellar system has no homology to the bacterial one and must have arisen by convergent evolution. However, it has been understood that the N-terminal domain of the archaeal flagellin is a homolog of the N-terminal domain of bacterial type IV pilin, showing once again how proteins can be repurposed in evolution for different functions. Using cryo-EM, we have been able to generate a nearly complete atomic model for a flagellar-like filament of the archaeon Ignicoccus hospitalis from a reconstruction at ∼4-Å resolution. We can now show that the archaeal flagellar filament contains a β-sandwich, previously seen in the FlaF protein that forms the anchor for the archaeal flagellar filament. In contrast to the bacterial flagellar filament, where the outer globular domains make no contact with each other and are not necessary for either assembly or motility, the archaeal flagellin outer domains make extensive contacts with each other that largely determine the interesting mechanical properties of these filaments, allowing these filaments to flex.
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Goosens, Vivianne J., Andreas Busch, Michaella Georgiadou, Marta Castagnini, Katrina T. Forest, Gabriel Waksman, and Vladimir Pelicic. "Reconstitution of a minimal machinery capable of assembling periplasmic type IV pili." Proceedings of the National Academy of Sciences 114, no. 25 (June 6, 2017): E4978—E4986. http://dx.doi.org/10.1073/pnas.1618539114.
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Type IV pili (Tfp), which are key virulence factors in many bacterial pathogens, define a large group of multipurpose filamentous nanomachines widespread in Bacteria and Archaea. Tfp biogenesis is a complex multistep process, which relies on macromolecular assemblies composed of 15 conserved proteins in model gram-negative species. To improve our limited understanding of the molecular mechanisms of filament assembly, we have used a synthetic biology approach to reconstitute, in a nonnative heterologous host, a minimal machinery capable of building Tfp. Here we show that eight synthetic genes are sufficient to promote filament assembly and that the corresponding proteins form a macromolecular complex at the cytoplasmic membrane, which we have purified and characterized biochemically. Our results contribute to a better mechanistic understanding of the assembly of remarkable dynamic filaments nearly ubiquitous in prokaryotes.
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Ching, GY, and RK Liem. "Assembly of type IV neuronal intermediate filaments in nonneuronal cells in the absence of preexisting cytoplasmic intermediate filaments." Journal of Cell Biology 122, no. 6 (September 15, 1993): 1323–35. http://dx.doi.org/10.1083/jcb.122.6.1323.
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We report here on the in vivo assembly of alpha-internexin, a type IV neuronal intermediate filament protein, in transfected cultured cells, comparing its assembly properties with those of the neurofilament triplet proteins (NF-L, NF-M, and NF-H). Like the neurofilament triplet proteins, alpha-internexin coassembles with vimentin into filaments. To study the assembly characteristics of these proteins in the absence of a preexisting filament network, transient transfection experiments were performed with a non-neuronal cell line lacking cytoplasmic intermediate filaments. The results showed that only alpha-internexin was able to self-assemble into extensive filamentous networks. In contrast, the neurofilament triplet proteins were incapable of homopolymeric assembly into filamentous arrays in vivo. NF-L coassembled with either NF-M or NF-H into filamentous structures in the transfected cells, but NF-M could not form filaments with NF-H. alpha-internexin could coassemble with each of the neurofilament triplet proteins in the transfected cells to form filaments. When all but 2 and 10 amino acid residues were removed from the tail domains of NF-L and NF-M, respectively, the resulting NF-L and NF-M deletion mutants retained the ability to coassemble with alpha-internexin into filamentous networks. These mutants were also capable of forming filaments with other wild-type neurofilament triplet protein subunits. These results suggest that the tail domains of NF-L and NF-M are dispensable for normal coassembly of each of these proteins with other type IV intermediate filament proteins to form filaments.
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Ching, G. Y., and R. K. Liem. "Analysis of the roles of the head domains of type IV rat neuronal intermediate filament proteins in filament assembly using domain-swapped chimeric proteins." Journal of Cell Science 112, no. 13 (July 1, 1999): 2233–40. http://dx.doi.org/10.1242/jcs.112.13.2233.
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Type IV neuronal intermediate filament proteins consist of alpha-internexin, which can self-assemble into filaments and the neurofilament triplet proteins, which are obligate heteropolymers, at least in rodents. These IF proteins therefore provide good systems for elucidating the mechanism of intermediate filament assembly. To analyze the roles of the head domains of these proteins in contributing to their differential assembly properties, we generated chimeric proteins by swapping the head domains between rat alpha-internexin and either rat NF-L or NF-M and examined their assembly properties in transfected cells that lack their own cytoplasmic intermediate filament network. Lalphaalpha and Malphaalpha, the chimeric proteins generated by replacing the head domain of alpha-internexin with those of NF-L and NF-M, respectively, were unable to self-assemble into filaments. In contrast, alphaLL, a chimeric NF-L protein generated by replacing the head domain of NF-L with that of alpha-internexin, was able to self-assemble into filaments, whereas MLL, a chimeric NF-L protein containing the NF-M head domain, was unable to do so. These results demonstrate that the alpha-internexin head domain is essential for alpha-internexin's ability to self-assemble. While coassembly of Lalphaalpha with NF-M and coassembly of Malphaalpha with NF-L resulted in formation of filaments, coassembly of Lalphaalpha with NF-L and coassembly of Malphaalpha with NF-M yielded punctate patterns. These coassembly results show that heteropolymeric filament formation requires that one partner has the NF-L head domain and the other partner has the NF-M head domain. Thus, the head domains of rat NF-L and NF-M play important roles in determining the obligate heteropolymeric nature of filament formation. The data obtained from these self-assembly and coassembly studies provide some new insights into the mechanism of intermediate filament assembly.
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Kraljic, Katarina, Christopher Duckworth, Rita Tojeiro, Shadab Alam, Dmitry Bizyaev, Anne-Marie Weijmans, Nicholas Fraser Boardman, and Richard R. Lane. "SDSS-IV MaNGA: 3D spin alignment of spiral and S0 galaxies." Monthly Notices of the Royal Astronomical Society 504, no. 3 (April 21, 2021): 4626–33. http://dx.doi.org/10.1093/mnras/stab1109.
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ABSTRACT We investigate the 3D spin alignment of galaxies with respect to the large-scale filaments using the MaNGA survey. The cosmic web is reconstructed from the Sloan Digital Sky Survey using disperse and the 3D spins of MaNGA galaxies are estimated using the thin disc approximation with integral field spectroscopy kinematics. Late-type spiral galaxies are found to have their spins parallel to the closest filament’s axis. The alignment signal is found to be dominated by low-mass spirals. Spins of S0-type galaxies tend to be oriented preferentially in perpendicular direction with respect to the filament’s axis. This orthogonal orientation is found to be dominated by S0s that show a notable misalignment between their kinematic components of stellar and ionized gas velocity fields and/or by low-mass S0s with lower rotation support compared to their high-mass counterparts. Qualitatively similar results are obtained when splitting galaxies based on the degree of ordered stellar rotation, such that galaxies with high spin magnitude have their spin aligned, and those with low spin magnitude in perpendicular direction to the filaments. In the context of conditional tidal torque theory, these findings suggest that galaxies’ spins retain memory of their larger scale environment. In agreement with measurements from hydrodynamical cosmological simulations, the measured signal at low redshift is weak, yet statistically significant. The dependence of the spin-filament orientation of galaxies on their stellar mass, morphology, and kinematics highlights the importance of sample selection to detect the signal.
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Couturier, Marc Roger, and Markus Stein. "Helicobacter pylori produces unique filaments upon host contact in vitro." Canadian Journal of Microbiology 54, no. 7 (July 2008): 537–48. http://dx.doi.org/10.1139/w08-042.
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Helicobacter pylori exists in 2 distinct morphological states, helicoid and coccoid. Both have been observed in in vitro culture and in gastric biopsies. We visualized H. pylori during AGS cell infections using immunofluorescence microscopy. Anti-H. pylori mouse serum as well as human serum from H. pylori-positive patients recognized long, thin bacterial filaments, which formed on helicoids and more frequently on coccoids. These filaments reached lengths of 59 μm and often connected bacteria. Periodate oxidation abolished antibody recognition, suggesting that carbohydrates compose a major antigenic component of the filaments. Similar to results obtained using immunofluorescence microscopy, scanning electron microscopy imaging revealed thin filamentous structures, which were absent on uninfected cells. Both coccoid conversion and filament development increased over the time course of infection with peak filament formation at 4 h. The number of visible filaments then decreased as bacteria clustered on the apical surface of AGS cells. Since the observed filaments were clearly distinct from previously described surface structures, including flagella and the cag type IV secretion system, our results demonstrate that these filaments represent a unique, previously unrecognized, organelle.
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Sheppard, Devon, Jamie-Lee Berry, Rémi Denise, Eduardo P. C. Rocha, Steve Matthews, and Vladimir Pelicic. "The major subunit of widespread competence pili exhibits a novel and conserved type IV pilin fold." Journal of Biological Chemistry 295, no. 19 (April 9, 2020): 6594–604. http://dx.doi.org/10.1074/jbc.ra120.013316.
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Type IV filaments (T4F), which are helical assemblies of type IV pilins, constitute a superfamily of filamentous nanomachines virtually ubiquitous in prokaryotes that mediate a wide variety of functions. The competence (Com) pilus is a widespread T4F, mediating DNA uptake (the first step in natural transformation) in bacteria with one membrane (monoderms), an important mechanism of horizontal gene transfer. Here, we report the results of genomic, phylogenetic, and structural analyses of ComGC, the major pilin subunit of Com pili. By performing a global comparative analysis, we show that Com pili genes are virtually ubiquitous in Bacilli, a major monoderm class of Firmicutes. This also revealed that ComGC displays extensive sequence conservation, defining a monophyletic group among type IV pilins. We further report ComGC solution structures from two naturally competent human pathogens, Streptococcus sanguinis (ComGCSS) and Streptococcus pneumoniae (ComGCSP), revealing that this pilin displays extensive structural conservation. Strikingly, ComGCSS and ComGCSP exhibit a novel type IV pilin fold that is purely helical. Results from homology modeling analyses suggest that the unusual structure of ComGC is compatible with helical filament assembly. Because ComGC displays such a widespread distribution, these results have implications for hundreds of monoderm species.
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Daehnel, Katrin, Robin Harris, Lucinda Maddera, and Philip Silverman. "Fluorescence assays for F-pili and their application." Microbiology 151, no. 11 (November 1, 2005): 3541–48. http://dx.doi.org/10.1099/mic.0.28159-0.
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Conjugative pili are extracellular filaments elaborated by Gram-negative bacteria expressing certain type IV secretion systems. They are required at the earliest stages of conjugal DNA transfer to establish specific and secure cell–cell contacts. Conjugative pili also serve as adsorption organelles for both RNA and DNA bacteriophages. Beyond these facts, the structure, formation and function of these filaments are poorly understood. This paper describes a rapid, quantitative assay for F-pili encoded by the F plasmid type IV secretion system. The assay is based on the specific lateral adsorption of icosahedral RNA bacteriophage R17 by F-pili. Bacteriophage particles conjugated with a fluorescent dye, Alexa 488, and bound to F-pili defined filaments visible by immunofluorescence microscopy. F-pili attached to F+ cells and free F-pili were both visible by this method. For quantification, cell-bound bacteriophage were separated from free bacteriophage particles by sedimentation and released by suspending cell pellets in 0·1 % SDS. Fluorescence in cell-free supernatant fractions was measured by fluorometry. The authors present a characterization of this assay and its application to F-pilus formation by cells carrying mutations in the gene for the F-pilus subunit F-pilin. Each mutation introduced a cysteine, which F-pilin normally lacks, at a different position in its primary structure. Cysteine residues in the N-terminal domain I abolished filament formation as measured by fluorescent R17 binding. This was confirmed by measurements of DNA donor activity and filamentous DNA bacteriophage infection. With one exception (G53C), cysteines elsewhere in the F-pilin primary structure did not abolish filament formation, although some mutations differentially affected F-pilus functions.
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Uddin, Wahab, and V. K. Verma. "Eruption of a Twisted Filament and Associated Phenomena." International Astronomical Union Colloquium 167 (1998): 338–41. http://dx.doi.org/10.1017/s0252921100047874.
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AbstractIn this paper we present CCD observations between February 14–20, 1994 and analysis of the giant twisted filament evolved in the active region NOAA 7671. The dynamic eruption of the filament was accompanied by a major flare (3B/M4), CME, long duration type II, IV radio bursts, great microwave bursts, a long duration soft X-ray burst, SIDs, strong geomagnetic storms and a very energetic proton flare. We analysed and estimated the twist, length, volume, mass and energy associated with filament system between February 14 and 20, 1994. The present study shows that the magnetic energy required for the solar flare came from the filament system associated with the solar flare and associated phenomena.
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Wang, Qiang, Genrich V. Tolstonog, Robert Shoeman, and Peter Traub. "Sites of Nucleic Acid Binding in Type I−IV Intermediate Filament Subunit Proteins†." Biochemistry 40, no. 34 (August 2001): 10342–49. http://dx.doi.org/10.1021/bi0108305.
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Lamparter, Tilman, Jennifer Babian, Katrin Fröhlich, Marion Mielke, Nora Weber, Nadja Wunsch, Finn Zais, et al. "The involvement of type IV pili and the phytochrome CphA in gliding motility, lateral motility and photophobotaxis of the cyanobacterium Phormidium lacuna." PLOS ONE 17, no. 1 (January 27, 2022): e0249509. http://dx.doi.org/10.1371/journal.pone.0249509.
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Phormidium lacuna is a naturally competent, filamentous cyanobacterium that belongs to the order Oscillatoriales. The filaments are motile on agar and other surfaces and display rapid lateral movements in liquid culture. Furthermore, they exhibit a photophobotactic response, a phototactic response towards light that is projected vertically onto the area covered by the culture. However, the molecular mechanisms underlying these phenomena are unclear. We performed the first molecular studies on the motility of an Oscillatoriales member. We generated mutants in which a kanamycin resistance cassette (KanR) was integrated in the phytochrome gene cphA and in various genes of the type IV pilin apparatus. pilM, pilN, pilQ and pilT mutants were defective in gliding motility, lateral movements and photophobotaxis, indicating that type IV pili are involved in all three kinds of motility. pilB mutants were only partially blocked in terms of their responses. pilB is the proposed ATPase for expelling of the filament in type IV pili. The genome reveals proteins sharing weak pilB homology in the ATPase region, these might explain the incomplete phenotype. The cphA mutant revealed a significantly reduced photophobotactic response towards red light. Therefore, our results imply that CphA acts as one of several photophobotaxis photoreceptors or that it could modulate the photophobotaxis response.
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Laureto, John J., and Joshua M. Pearce. "Anisotropic mechanical property variance between ASTM D638-14 type i and type iv fused filament fabricated specimens." Polymer Testing 68 (July 2018): 294–301. http://dx.doi.org/10.1016/j.polymertesting.2018.04.029.
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Gimona, Mario. "An alternatively spliced exon links intermediate filaments to adhesions." Biochemical Journal 409, no. 3 (January 15, 2008): e1-e2. http://dx.doi.org/10.1042/bj20071674.
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Anchorage of the contractile actomyosin apparatus to the plasma membrane at discrete sites in muscle and non-muscle cells enables the transmission and conversion of force into work, such as muscle contraction and membrane deformation to regulate cell and tissue shape. Assembly, stabilization and turnover of adhesion sites are complex processes that involve structural components, a variety of signalling and adapter molecules, diverse kinases and phosphatases, and phospholipids. The dynamic turnover of adhesions also requires the frequent interaction with other filament systems of the cytoskeleton, in particular with microtubules. How the delivery and activation of all the required components is co-ordinated, however, remains to be fully understood. In the current issue of Biochemical Journal, Sun et al. provide evidence that a specific exon that is exclusively present in the α variant of the type IV intermediate filament protein synemin interacts directly with the focal adhesion protein vinculin in its active state. Interaction of adhesion components with intermediate filaments could serve as a general mechanism to regulate cell- and tissue-specific cytoskeleton-membrane attachment.
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Ching, G. Y., and R. K. Liem. "Roles of head and tail domains in alpha-internexin's self-assembly and coassembly with the neurofilament triplet proteins." Journal of Cell Science 111, no. 3 (February 1, 1998): 321–33. http://dx.doi.org/10.1242/jcs.111.3.321.
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The roles of the head and tail domains of alpha-internexin, a type IV neuronal intermediate filament protein, in its self-assembly and coassemblies with neurofilament triplet proteins, were examined by transient transfections with deletion mutants in a non-neuronal cell line lacking an endogenous cytoplasmic intermediate filament network. The results from the self-assembly studies showed that the head domain was essential for alpha-internexin's ability to self-assemble into a filament network and the tail domain was important for establishing a proper filament network. The data from the coassembly studies demonstrated that alpha-internexin interacted differentially with the neurofilament triplet protein subunits. Wild-type NF-L or NF-M, but not NF-H, was able to complement and form a normal filament network with the tailless alpha-internexin mutant, the alpha-internexin head-deletion mutant, or the alpha-internexin mutant missing the entire tail and some amino-terminal portion of the head domain. In contrast, neither the tailless NF-L mutant nor the NF-L head-deletion mutant was able to form a normal filament network with any of these alpha-internexin deletion mutants. However, coassembly of the tailless NF-M mutant with the alpha-internexin head-deletion mutant and coassembly of the NF-M head-deletion mutant with the tailless alpha-internexin mutant resulted in the formation of a normal filament network. Thus, the coassembly between alpha-internexin and NF-M exhibits some unique characteristics previously not observed with other intermediate filament proteins: only one intact tail and one intact head are required for the formation of a normal filament network, and they can be present within the same partner or separately in two partners.
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Reddy, T. R., X. Li, Y. Jones, M. H. Ellisman, G. Y. Ching, R. K. H. Liem, and F. Wong-Staal. "Specific interaction of HTLV tax protein and a human type IV neuronal intermediate filament protein." Proceedings of the National Academy of Sciences 95, no. 2 (January 20, 1998): 702–7. http://dx.doi.org/10.1073/pnas.95.2.702.
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Mignot, Tâm, John P. Merlie, and David R. Zusman. "Regulated Pole-to-Pole Oscillations of a Bacterial Gliding Motility Protein." Science 310, no. 5749 (November 3, 2005): 855–57. http://dx.doi.org/10.1126/science.1119052.
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Little is known about directed motility of bacteria that move by type IV pilus–mediated (twitching) motility. Here, we found that during periodic cell reversals ofMyxoccocus xanthus, type IV pili were disassembled at one pole and reassembled at the other pole. Accompanying these reversals, FrzS, a protein required for directed motility, moved in an oscillatory pattern between the cell poles. The frequency of the oscillations was controlled by the Frz chemosensory system, which is essential for directed motility. Pole-to-pole migration of FrzS appeared to involve movement along a filament running the length of the cell. FrzS dynamics may thus regulate cell polarity during directed motility.
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Jacomy, Hélène, Qinzang Zhu, Sébastien Couillard-Després, Jean-Martin Beaulieu, and Jean-Pierre Julien. "Disruption of Type IV Intermediate Filament Network in Mice Lacking the Neurofilament Medium and Heavy Subunits." Journal of Neurochemistry 73, no. 3 (December 25, 2001): 972–84. http://dx.doi.org/10.1046/j.1471-4159.1999.0730972.x.
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Luke, Nicole R., Amy J. Howlett, Jianqiang Shao, and Anthony A. Campagnari. "Expression of Type IV Pili by Moraxella catarrhalis Is Essential for Natural Competence and Is Affected by Iron Limitation." Infection and Immunity 72, no. 11 (November 2004): 6262–70. http://dx.doi.org/10.1128/iai.72.11.6262-6270.2004.
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ABSTRACT Type IV pili, filamentous surface appendages primarily composed of a single protein subunit termed pilin, play a crucial role in the initiation of disease by a wide range of pathogenic bacteria. Although previous electron microscopic studies suggested that pili might be present on the surface of Moraxella catarrhalis isolates, detailed molecular and phenotypic analyses of these structures have not been reported to date. We identified and cloned the M. catarrhalis genes encoding PilA, the major pilin subunit, PilQ, the outer membrane secretin through which the pilus filament is extruded, and PilT, the NTPase that mediates pilin disassembly and retraction. To initiate investigation of the role of this surface organelle in pathogenesis, isogenic pilA, pilT, and pilQ mutants were constructed in M. catarrhalis strain 7169. Comparative analyses of the wild-type 7169 strain and three isogenic pil mutants demonstrated that M. catarrhalis expresses type IV pili that are essential for natural genetic transformation. Our studies suggest type IV pilus production by M. catarrhalis is constitutive and ubiquitous, although pilin expression was demonstrated to be iron responsive and Fur regulated. These data indicate that additional studies aimed at elucidating the prevalence and role of type IV pili in the pathogenesis and host response to M. catarrhalis infections are warranted.
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Ralton, J. E., X. Lu, A. M. Hutcheson, and R. A. Quinlan. "Identification of two N-terminal non-alpha-helical domain motifs important in the assembly of glial fibrillary acidic protein." Journal of Cell Science 107, no. 7 (July 1, 1994): 1935–48. http://dx.doi.org/10.1242/jcs.107.7.1935.
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The non-alpha-helical N-terminal domain of intermediate filament proteins plays a key role in filament assembly. Previous studies have identified a nonapeptide motif, SSYRRIFGG, in the non-alpha-helical N-terminal domain of vimentin that is required for assembly. This motif is also found in desmin, peripherin and the type IV intermediate filament proteins. GFAP is the only type III intermediate filament protein in which this motif is not readily identified. This study has identified two motifs in the non-alpha-helical N-terminal domain of mouse GFAP that play important roles in GFAP assembly. One motif is located at the very N terminus and has the consensus sequence, MERRRITS-ARRSY. It has some characteristics in common with the vimentin nonapeptide motif, SSYRRIFGG, including its location in the non-alpha-helical N-terminal domain and a concentration of arginine residues. Unlike the vimentin motif in which even conserved sequence changes affect filament assembly, the GFAP consensus sequence, MERRRITS-ARRSY, can be replaced by a completely unrelated sequence; namely, the heptapeptide, MVRANKR, derived from the lambda cII protein. When fused to GFAP sequences with sequential deletions of the N-terminal domain, the lambda cII heptapeptide was used to help identify a second motif, termed the RP-box, which is located just upstream of the GFAP alpha-helical rod domain. This RP-box affected the efficiency of filament assembly as well as protein-protein interactions in the filament, as shown by sedimentation assays and electron microscopy. These results are supported by previous data, which showed that the dramatic reorganization of GFAP within cells was due to phosphorylation-dephosphorylation of a site located in this RP-box. The results in this study suggest the RP-box motif to be a key modulator in the mechanism of GFAP assembly, and support a role for this motif in both the nucleation and elongation phases of filament assembly. The RP-box motif in GFAP has the consensus sequence, RLSL-RM-PP. Sequences similar to the GFAP RP-box motif are also to be found in vimentin, desmin and peripherin. Like GFAP, these include phosphorylation and proteolysis sites and are adjacent to the start of the central alpha-helical rod domain, suggesting that this motif of general importance to type III intermediate filament protein assembly.
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Subakti, Yulian, Hasdiansah -, and Zaldy Kurniawan. "Pengaruh Media, Temperatur Dan Waktu Perlakuan Annealing Pada Spesimen Standar ASTM D638 Type IV Menggunakan Filamen ST PLA." SPROCKET JOURNAL OF MECHANICAL ENGINEERING 3, no. 1 (August 22, 2021): 7–14. http://dx.doi.org/10.36655/sprocket.v3i1.569.
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Fused Deposition Modeling (FDM) is a technique of 3D Printing machines that is popularly used to print products. The printed product certainly has the ideal tensile strength characteristics if it has a precise size and good shape according to the standard. One of the materials that can be processed in a 3D printing machine is ST PLA. Research in terms of tensile testing has been carried out on PLA/ABS materials. However, tensile testing with annealing process using ST PLA filament is still very rarely done. From these problems, it is necessary to research to obtain optimal process parameters on 3D printing machines, to obtain the highest tensile strength from the annealing process using ST PLA material. This research was conducted using a 3D printer DIY Prusa model with a printing area of XYZ, 300 mm x 300 mm x 350 mm. The material used is ST PLA filament with a diameter of 1.75 mm in green. The process parameters in this research are layer thickness, nozzle temperature and flow rate. For annealing media use beach sand, coffee and wheat. The shape of the test specimen follows the ASTM D638 type IV standard. As for the design of the process parameters using the Taguchi L9 method (33). The process parameter values that produce the highest tensile strength without annealing are layer thickness 0.3 mm, nozzle temperature 205oC, and flow rate 100%. The annealing process parameters that produce the highest tensile strength are annealing time of 15 minutes, oven temperature of 110oC, for annealing media using coffee.
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Chin, S. S., P. Macioce, and R. K. Liem. "Effects of truncated neurofilament proteins on the endogenous intermediate filaments in transfected fibroblasts." Journal of Cell Science 99, no. 2 (June 1, 1991): 335–50. http://dx.doi.org/10.1242/jcs.99.2.335.
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The expression and assembly characteristics of carboxyl- and amino-terminal deletion mutants of rat neurofilament low Mr (NF-L) and neurofilament middle Mr (NF-M) proteins were examined by transient transfection of cultured fibroblasts. Deletion of the carboxyl-terminal tail domain of either protein indicated that this region was not absolutely essential for co-assembly into the endogenous vimentin cytoskeleton. However, deletion into the alpha-helical rod domain resulted in an inability of the mutant proteins to co-assemble with vimentin into filamentous structures. Instead, the mutant proteins appeared to be assembled into unusual tubular-vesicular structures. Additionally, these latter deletions appeared to act as dominant negative mutants which induced the collapse of the endogenous vimentin cytoskeleton as well as the constitutively expressed NF-H and NF-M cytoskeletons in stably transfected cell lines. Thus, an intact alpha-helical rod domain was essential for normal IF co-assembly whereas carboxyl-terminal deletions into this region resulted in dramatic alterations of the existing type III and IV intermediate filament cytoskeletons in vivo. Deletions from the amino-terminal end into the alpha-helical rod region gave different results. With these deletions, the transfected protein was not co-assembled into filaments and the endogenous vimentin IF network was not disrupted, indicating that these deletion mutants are recessive. The dominant negative mutants may provide a novel approach to studying intermediate filament function within living cells.
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Denise, Rémi, Sophie S. Abby, and Eduardo P. C. Rocha. "Diversification of the type IV filament superfamily into machines for adhesion, protein secretion, DNA uptake, and motility." PLOS Biology 17, no. 7 (July 19, 2019): e3000390. http://dx.doi.org/10.1371/journal.pbio.3000390.
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Cohen-Krausz, Sara, and Shlomo Trachtenberg. "The Structure of the Archeabacterial Flagellar Filament of the Extreme Halophile Halobacterium salinarum R1M1 and Its Relation to Eubacterial Flagellar Filaments and Type IV Pili." Journal of Molecular Biology 321, no. 3 (August 2002): 383–95. http://dx.doi.org/10.1016/s0022-2836(02)00616-2.
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Pato, M. D., A. G. Tulloch, M. P. Walsh, and E. Kerc. "Smooth muscle phosphatases: structure, regulation, and function." Canadian Journal of Physiology and Pharmacology 72, no. 11 (November 1, 1994): 1427–33. http://dx.doi.org/10.1139/y94-206.
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Smooth muscle contraction is regulated primarily by the reversible phosphorylation of myosin by myosin light chain kinase. Secondary mechanisms that might modulate contractility are phosphorylation–dephosphorylation of myosin light chain kinase and thin-filament proteins, caldesmon and calponin. Purification of several protein phosphatases that are active toward myosin light chains and (or) myosin and heavy meromyosin from smooth muscles has been reported. All the cytosolic turkey gizzard smooth muscle phosphatases, termed SMP-I, -II, -III, and -IV, dephosphorylate myosin light chains rapidly, but only SMP-III and -IV are active toward myosin and heavy meromyosin, suggesting that SMP-III and -IV might be directly involved in the relaxation of smooth muscle. SMP-III and -IV exhibit properties typical of type 1 protein phosphatases following tryptic digestion. These enzymes appear to share structural similarity with myofibrillar phosphatase PP1M. Purified calponin phosphatase and caldesmon phosphatase from chicken gizzards are structurally and immunologically identical with SMP-I, a type 2A protein phosphatase. SMP-I dephosphorylates calponin faster than it does caldesmon, and has much higher activity toward these substrates than SMP-II, -III, and -IV. Thus, one role for SMP-I might be to regulate the activities of caldesmon and calponin. Since SMP-I is active toward myosin light chain kinase, it might also modulate this enzyme.Key words: smooth muscle, contractility, protein phosphatases, smooth muscle phosphatases.
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Bischof, Lisa Franziska, Maria Florencia Haurat, and Sonja-Verena Albers. "Two membrane-bound transcription factors regulate expression of various type-IV-pili surface structures in Sulfolobus acidocaldarius." PeerJ 7 (February 26, 2019): e6459. http://dx.doi.org/10.7717/peerj.6459.
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In Archaea and Bacteria, gene expression is tightly regulated in response to environmental stimuli. In the thermoacidophilic crenarchaeon Sulfolobus acidocaldarius nutrient limitation induces expression of the archaellum, the archaeal motility structure. This expression is orchestrated by a complex hierarchical network of positive and negative regulators—the archaellum regulatory network (arn). The membrane-bound one-component system ArnR and its paralog ArnR1 were recently described as main activators of archaellum expression in S. acidocaldarius. They regulate gene expression of the archaellum operon by targeting the promoter of flaB, encoding the archaellum filament protein. Here we describe a strategy for the isolation and biochemical characterization of these two archaellum regulators. Both regulators are capable of forming oligomers and are phosphorylated by the Ser/Thr kinase ArnC. Apart from binding to pflaB, ArnR but not ArnR1 bound to promoter sequences of aapF and upsX, which encode components of the archaeal adhesive pilus and UV-inducible pili system, demonstrating a regulatory connection between different surface appendages of S. acidocaldarius.
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Hwang, Jaiweon, David Bieber, Sandra W. Ramer, Cheng-Yen Wu, and Gary K. Schoolnik. "Structural and Topographical Studies of the Type IV Bundle-Forming Pilus Assembly Complex of Enteropathogenic Escherichia coli." Journal of Bacteriology 185, no. 22 (November 15, 2003): 6695–701. http://dx.doi.org/10.1128/jb.185.22.6695-6701.2003.
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ABSTRACT The type IV bundle-forming pili (BFP) of enteropathogenic Escherichia coli (EPEC) are required for virulence in orally challenged human volunteers and for the localized adherence and autoaggregation in vitro phenotypes. BFP filament biogenesis and function are encoded by the 14-gene bfp operon. The BFP assembly complex, containing a BfpB-His6 fusion protein, was chemically cross-linked in situ, and the complex was then purified from BFP-expressing EPEC by a combination of nickel- and BfpB antibody-based affinity chromatography. Characterization of the isolated complex by immunoblotting using BFP protein-specific antibodies showed that at least 10 of the 14 proteins specified by the bfp operon physically interact to form an oligomeric complex. Proteins localized to the outer membrane, inner membrane, and periplasm are within this complex, thus demonstrating that the complex spans the periplasmic space. A combination of immunofluorescence and immuno-gold thin-section transmission electron microscopy studies localized this complex to one pole of the cell.
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Moorer, Megan C., Atum M. Buo, Karla P. Garcia-Pelagio, Joseph P. Stains, and Robert J. Bloch. "Deficiency of the intermediate filament synemin reduces bone mass in vivo." American Journal of Physiology-Cell Physiology 311, no. 6 (December 1, 2016): C839—C845. http://dx.doi.org/10.1152/ajpcell.00218.2016.
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While the type IV intermediate filament protein, synemin, has been shown to play a role in striated muscle and neuronal tissue, its presence and function have not been described in skeletal tissue. Here, we report that genetic ablation of synemin in 14-wk-old male mice results in osteopenia that includes a more than 2-fold reduction in the trabecular bone fraction in the distal femur and a reduction in the cross-sectional area at the femoral middiaphysis due to an attendant reduction in both the periosteal and endosteal perimeter. Analysis of serum markers of bone formation and static histomorphometry revealed a statistically significant defect in osteoblast activity and osteoblast number in vivo. Interestingly, primary osteoblasts isolated from synemin-null mice demonstrate markedly enhanced osteogenic capacity with a concomitant reduction in cyclin D1 mRNA expression, which may explain the loss of osteoblast number observed in vivo. In total, these data suggest an important, previously unknown role for synemin in bone physiology.
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Yi, Hong, Norman E. Williams, Virginia M. Dress, and Kenneth C. Moore. "Immunolocalization of individual filament-forming proteins in the cytoskeleton of Tetrahymena." Proceedings, annual meeting, Electron Microscopy Society of America 48, no. 3 (August 12, 1990): 476–77. http://dx.doi.org/10.1017/s0424820100159928.
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Four polypeptides (tetrins I-IV) have been isolated from the ciliated protozoan Tetrahvmena pyriformis. These polypeptides assemble in vitro into 3-4 nm filaments identical with those present in abundance in a cytoskeletal framework associated with the feeding organelle system (oral apparatus) of this cell type. The polypeptides ranging in molecular weights from 79-89 kDa are not similar to each other in either biochemical or immunological properties. In vivo, the filaments are organized into higher order structures described as cages, cables, and networks. The specific hypothesis arises that the alternate packing arrangements may correlate with different distributions of the individual tetrin polypeptides. We report the production of monoclonal antibodies for each tetrin polypeptide, and the determination of the location of each within the cell using confocal microscopy and immunogold-silver enhancement procedures in conjunction with transmission electron microscopy (TEM).Cell samples for confocal microscopy were labelled according to conventional immunofluorescent procedures and examined with a Bio-Rad MRC-600 laser scanning confocal microscope.
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Coulon, Josiane, Monique Diano, Jean-Pierre Arsanto, and Yves Thouveny. "Remodeling processes during anterior regeneration of Owenia fusiformis (Polychaeta, Annelidae): a morphological and immunocytochemical survey." Canadian Journal of Zoology 67, no. 4 (April 1, 1989): 994–1005. http://dx.doi.org/10.1139/z89-143.
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Morphological and immunocytochemical studies were used to determine the correlations among cytoskeleton, junction complex, and basement membrane reorganization during anterior regeneration in Owenia fusiformis. Electron microscopical observations showed that, at the point of amputation, in conjunction with the disorganization of the extracellular matrix, alterations in the adhesive junctions caused dramatic changes in the distribution of intermediary filaments. Fluorescence microscopy investigations with fluorescein – phalloidin and antibodies to actin and Owenia tropomyosin visualized a basal actin network in epidermal cells, which was reorganized during regeneration. Two or three days after amputation, this cortical mat was not observed in blastema where the basal membrane was lacking. It was still incompletely reassembled after 4 or 5 days, i.e., when the thin reforming basal membrane, which stained with anti type IV collagen antibody, did not yet display collagen fibrils. In the epidermis of 6- to 7-day-old regenerates, the basal membrane, intercellular junctions, and actin and intermediary filament cytoskeletons exhibited nearly normal structural features. Use of antibody to Owenia paramyosin showed that the reorganization of the muscles during regeneration was concomitant with actin cytoskeletal reconstruction, as appeared after antitropomyosin labeling. Immunofluorescence findings were checked and (or) specified by immunogold staining.
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JIMI, NAOTO, YOSHIHIRO FUJIWARA, and HIROSHI KAJIHARA. "New annelid species from the deepest known whale-fall environment: Bathykermadeca thanatos sp. nov. (Annelida: Polynoidae)." Zootaxa 4450, no. 5 (July 27, 2018): 575. http://dx.doi.org/10.11646/zootaxa.4450.5.4.
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A new species of polynoid annelids, Bathykermadeca thanatos sp. nov., is described based on specimens collected from sunken whale bones in the Nansei-Shoto Trench in the Philippine Sea at a depth of 4974 m. The cetacean-carcass community at the site exceeds the deepest record reported to date. This new species can be distinguished from other members of the genus by the following features: i) there is only one type of neurochaetae, ii) the teeth lack serration and grow inwardly, iii) median antenna extends beyond the tip of frontal filament, iv) nephridial papillae are present in segments 12–15, and v) there are about 50 notochaetae in each parapodium.
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Kharadi, Roshni R., Kayla Selbmann, and George W. Sundin. "A complete twelve-gene deletion null mutant reveals that cyclic di-GMP is a global regulator of phase-transition and host colonization in Erwinia amylovora." PLOS Pathogens 18, no. 8 (August 1, 2022): e1010737. http://dx.doi.org/10.1371/journal.ppat.1010737.
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Cyclic-di-GMP (c-di-GMP) is an essential bacterial second messenger that regulates biofilm formation and pathogenicity. To study the global regulatory effect of individual components of the c-di-GMP metabolic system, we deleted all 12 diguanylate cyclase (dgc) and phosphodiesterase (pde)-encoding genes in E. amylovora Ea1189 (Ea1189Δ12). Ea1189Δ12 was impaired in surface attachment due to a transcriptional dysregulation of the type IV pilus and the flagellar filament. A transcriptomic analysis of surface-exposed WT Ea1189 and Ea1189Δ12 cells indicated that genes involved in metabolism, appendage generation and global transcriptional/post-transcriptional regulation were differentially regulated in Ea1189Δ12. Biofilm formation was regulated by all 5 Dgcs, whereas type III secretion and disease development were differentially regulated by specific Dgcs. A comparative transcriptomic analysis of Ea1189Δ8 (lacks all five enzymatically active dgc and 3 pde genes) against Ea1189Δ8 expressing specific dgcs, revealed the presence of a dual modality of spatial and global regulatory frameworks in the c-di-GMP signaling network.
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Lee, Yichen, Bo H. Lee, William Yip, Pingchen Chou, and Bak-Sau Yip. "Neurofilament Proteins as Prognostic Biomarkers in Neurological Disorders." Current Pharmaceutical Design 25, no. 43 (January 9, 2020): 4560–69. http://dx.doi.org/10.2174/1381612825666191210154535.
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Neurofilaments: light, medium, and heavy (abbreviated as NF-L, NF-M, and NF-H, respectively), which belong to Type IV intermediate filament family (IF), are neuron-specific cytoskeletal components. Neurofilaments are axonal structural components and integral components of synapses, which are important for neuronal electric signal transmissions along the axons and post-translational modification. Abnormal assembly of neurofilaments is found in several human neurodegenerative diseases such as amyotrophic lateral sclerosis (ALS), infantile spinal muscular atrophy (SMA), and hereditary sensory-motor neuropathy (HSMN). In addition, those pathological neurofilament accumulations are known in α-synuclein in Parkinson’s disease (PD), Aβ and tau in Alzheimer’s disease (AD), polyglutamine in CAG trinucleotide repeat disorders, superoxide dismutase 1 (SOD1), TAR DNA-binding protein 43 (TDP43), neuronal FUS proteins, optineurin (OPTN), ubiquilin 2 (UBQLN2), and dipeptide repeat protein (DRP) in amyotrophic lateral sclerosis (ALS). When axon damage occurs in central nervous disorders, neurofilament proteins are released and delivered into cerebrospinal fluid (CSF), which are then circulated into blood. New quantitative analyses and assay techniques are well-developed for the detection of neurofilament proteins, particularly NF-L and the phosphorylated NF-H (pNF-H) in CSF and serum. This review discusses the potential of using peripheral blood NF quantities and evaluating the severity of damage in the nervous system. Intermediate filaments could be promising biomarkers for evaluating disease progression in different nervous system disorders.
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Mondal, Rajesh, Zeus Saldaña-Ahuactzi, Jorge Soria-Bustos, Andrew Schultz, Jorge A. Yañez-Santos, Ygnacio Martínez Laguna, María L. Cedillo-Ramírez, and Jorge A. Girón. "The EcpD Tip Adhesin of the Escherichia coli Common Pilus Mediates Binding of Enteropathogenic E. coli to Extracellular Matrix Proteins." International Journal of Molecular Sciences 23, no. 18 (September 8, 2022): 10350. http://dx.doi.org/10.3390/ijms231810350.
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The attachment of enteropathogenic Escherichia coli (EPEC) to intestinal epithelial cells is facilitated by several adhesins; however, the individual host-cell receptors for pili-mediated adherence have not been fully characterized. In this study, we evaluated the hypothesis that the E. coli common pilus (ECP) tip adhesin protein EcpD mediates attachment of EPEC to several extracellular matrix (ECM) glycoproteins (fibronectin, laminin, collagens I and IV, and mucin). We found that the ΔecpA mutant, which lacks production of the EcpA filament but retains EcpD on the surface, adhered to these glycoproteins below the wild-type levels, while the ΔecpD mutant, which does not display EcpA or EcpD, bound significantly less to these host glycoproteins. In agreement, a purified recombinant EcpD subunit bound significantly more than EcpA to laminin, fibronectin, collagens I and IV, and mucin in a dose-dependent manner. These are compelling data that strongly suggest that ECP-producing EPEC may bind to host ECM glycoproteins and mucins through the tip adhesin protein EcpD. This study highlights the versatility of EPEC to bind to different host proteins and suggests that the interaction of ECP with the host’s ECM glycoproteins may facilitate colonization of the intestinal mucosal epithelium.
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Schmidt, Sarah A., David Bieber, Sandra W. Ramer, Jaiweon Hwang, Cheng-Yen Wu, and Gary Schoolnik. "Structure-Function Analysis of BfpB, a Secretin-Like Protein Encoded by the Bundle-Forming-Pilus Operon of EnteropathogenicEscherichia coli." Journal of Bacteriology 183, no. 16 (August 15, 2001): 4848–59. http://dx.doi.org/10.1128/jb.183.16.4848-4859.2001.
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ABSTRACT Production of type IV bundle-forming pili by enteropathogenicEscherichia coli (EPEC) requires BfpB, an outer-membrane lipoprotein and member of the secretin protein superfamily. BfpB was found to compose a ring-shaped, high-molecular-weight outer-membrane complex that is stable in 4% sodium dodecyl sulfate at temperatures of ≤65°C. Chemical cross-linking and immunoprecipitation experiments disclosed that the BfpB multimeric complex interacts with BfpG, and mutational studies showed that BfpG is required for the formation and/or stability of the multimer but not for the outer-membrane localization of BfpB. Formation of the BfpB multimer also does not require BfpA, the repeating subunit of the pilus filament. Functional studies of the BfpB-BfpG complex revealed that its presence confers vancomycin sensitivity, indicating that it may form an incompletely gated channel through the outer membrane. BfpB expression is also associated with accumulation of EPEC proteins in growth medium, suggesting that it may support both pilus biogenesis and protein secretion.
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Girón, María E., Irma Aguilar, and Alexis Rodríguez-Acosta. "Immunohistochemical changes in kidney glomerular and tubular proteins caused by rattlesnake (Crotalus vegrandis) venom." Revista do Instituto de Medicina Tropical de São Paulo 45, no. 5 (October 2003): 239–44. http://dx.doi.org/10.1590/s0036-46652003000500001.
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Renal damage is an important cause of death in patients who have survived the early effects of severe crotalid envenomation. Extracellular matrix of renal tissue is altered by Crotalus toxin activities. The aim of this study was to describe how cytoskeletal proteins and basal membrane components undergo substantial alterations under the action of Crotalus vegrandis crude venom and its hemorrhagic fraction (Uracoina-1) in mice. To detect the proteins in question, the immunoperoxidase method with monoclonal and polyclonal antibodies was used. Cell types within renal lesions were characterized by phenotypic identification, by means of immunohistologic analysis of marker proteins using different primary antibodies against mesangial cells, endothelial cells, cytoskeletal proteins (intermediate filament), extracellular matrix and basal membranes. Samples for morphological study by standard procedures (biotin-streptavidin-peroxidase technique) using light microscopy were processed. Positive and negative controls for each antigen tested in the staining assay were included. After crude venom and hemorrhagic fraction inoculation of mice, the disappearance of cytoskeletal vimentin and desmin and collagen proteins in the kidney was observed. In extracellular matrix and basal membranes, collagen type IV from envenomed animals tends to disappear from 24 h to 120 h after venom injection.
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Zhang, Q. M., Z. H. Huang, Y. J. Hou, D. Li, Z. J. Ning, and Z. Wu. "Spectroscopic observations of a flare-related coronal jet." Astronomy & Astrophysics 647 (March 2021): A113. http://dx.doi.org/10.1051/0004-6361/202038924.
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Context. Coronal jets are ubiquitous in active regions and coronal holes. Aims. In this paper, we study a coronal jet related to a C3.4 circular-ribbon flare in the active region 12434 on 2015 October 16. Methods. The flare and jet were observed in ultraviolet and extreme ultraviolet wavelengths by the Atmospheric Imaging Assembly on board the Solar Dynamics Observatory (SDO). The line-of-sight magnetograms of the photosphere were observed by the Helioseismic and Magnetic Imager on board SDO. The whole event was covered by the Interface Region Imaging Spectrograph during its imaging and spectroscopic observations. Soft X-ray fluxes of the flare were recorded by the GOES spacecraft. Hard X-ray (HXR) fluxes at 4−50 keV were obtained from observations of RHESSI and Fermi. Radio dynamic spectra of the flare were recorded by the ground-based stations belonging to the e-Callisto network. Results. Two minifilaments were located under a 3D fan-spine structure before flare. The flare was generated by the eruption of one filament. The kinetic evolution of the jet was divided into two phases: a slow rise phase at a speed of ∼131 km s−1 and a fast rise phase at a speed of ∼363 km s−1 in the plane-of-sky. The slow rise phase may correspond to the impulsive reconnection at the breakout current sheet. The fast rise phase may correspond to magnetic reconnection at the flare current sheet. The transition between the two phases occurred at ∼09:00:40 UT. The blueshifted Doppler velocities of the jet in the Si IV 1402.80 Å line range from −34 to −120 km s−1. The accelerated high-energy electrons are composed of three groups. Those propagating upward along the open field generate type III radio bursts, while those propagating downward produce HXR emissions and drive chromospheric condensation observed in the Si IV line. The electrons trapped in the rising filament generate a microwave burst lasting for ≤40 s. Bidirectional outflows at the base of jet are manifested by significant line broadenings of the Si IV line. The blueshifted Doppler velocities of outflows range from −13 to −101 km s−1. The redshifted Doppler velocities of outflows range from ∼17 to ∼170 km s−1. Conclusions. Our multiwavelength observations of the flare-related jet are in favor of the breakout jet model and are important for understanding the acceleration and transport of nonthermal electrons.
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Warburton, M. J., S. A. Ferns, C. M. Hughes, and P. S. Rudland. "Characterization of rat mammary cell types in primary culture: lectins and antisera to basement membrane and intermediate filament proteins as indicators of cellular heterogeneity." Journal of Cell Science 79, no. 1 (November 1, 1985): 287–304. http://dx.doi.org/10.1242/jcs.79.1.287.
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Three morphologically distinct major cell types were observed in primary cultures obtained from the mammary parenchyma of glands from virgin rats. These cell types consisted of small cuboidal epithelial cells, larger epithelioid cells and elongated cells. We have investigated the distribution of the basement membrane proteins laminin and type IV collagen, and the intermediate filament proteins vimentin and prekeratin, in these three cell types using immunofluorescence techniques. Antisera to the basement membrane proteins stain the large epithelioid cells and the elongated cells, but do not stain the small cuboidal cells. Polyclonal antiserum to keratin stains all the small cuboidal and large epithelioid cells, but only a small subpopulation of the elongated cells. However, a monoclonal antibody to keratin, LP34, stains only the large cuboidal and a proportion of the elongated cells. Vimentin antiserum fails to stain the small cuboidal cells but stains all the large epithelioid and elongated cells. In addition, peanut lectin, which binds only to ductal lining epithelial cells in the virgin rat mammary gland in vivo after their treatment with neuraminidase, binds to the small cuboidal cells after neuraminidase treatment but not to the other cell types. However, Griffonia simplicifolia agglutinin I, which specifically stains myoepithelial cells in vivo, binds to the large epithelioid and elongated cells but not to the small cuboidal cells. These results suggest that the small cuboidal cells are related to mammary ductal epithelial cells whereas the large epithelial and elongated cells have some characteristics of myoepithelial cells.
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BRIGITTE, PLANADE, BAIN ODILE, LENA JEAN-PAUL, and JOLY PIERRE. "Gyrinicola chabadamsoni n. sp. and G. tba (Dinnik 1933) (Nematoda, Oxyuroidea) from tadpoles of the hybridogenetic complex Rana lessonae-esculenta (Amphibia, Ranoidea)." Zootaxa 1764, no. 1 (May 7, 2008): 25. http://dx.doi.org/10.11646/zootaxa.1764.1.3.
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Two morphological types of the viviparous oxyurid nematode Gyrinicola were recovered from waterfrog tadpoles in France (Ain department, Rhône-Alpes region) and assigned to two species: G. tba (Dinnik 1930), redescribed, and G. chabadamsoni n. sp. Gyrinicola tba is close to G. batrachiensis (Walton 1929) and G. chabaudi Araujo and Artigas 1982 in that the female possesses a long tail and few cuticular buccal flaps. The new species, type host Rana kl. esculenta, is distinct by several characters: in females, by the 12 cuticular buccal flaps with internal crests, short caudal filament, short ovary producing embryonated eggs and large uterine pouch containing males and embryos, like in G. japonica Yamaguti 1938, and narrower thick-shelled eggs with subapical elongated operculum; in males, by the round genital cone, the third caudal pair of papillae at mid tail, length of the body and caudal part. Gyrinicola tba and the new species were found in R. lessonae and in the hybrid R. kl. esculenta but each with different seasonal infection rates. Comparative analyses of the data from the five Gyrinicola species were done. All females have one genital tract producing thick-shelled female eggs. The second genital tract is one of four types corresponding to different reproductive patterns: i) it forms a uterine pouch containing males in G. chabadamsoni and G. japonica; ii) it forms a slender uterus containing numerous autoinfective larval stages in G. batrachiensis from R. clamitans; iii) it forms a slender uterus containing only a few embryos in G. tba and G. chabaudi; and iv) it has regressed in G. batrachiensis from Bufo americanus. Haplodiploidy is expected or proved for types i) and ii) and thelytoky for types iii) and iv).
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Mooney, D. J., R. Langer, and D. E. Ingber. "Cytoskeletal filament assembly and the control of cell spreading and function by extracellular matrix." Journal of Cell Science 108, no. 6 (June 1, 1995): 2311–20. http://dx.doi.org/10.1242/jcs.108.6.2311.
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This study was undertaken to analyze how cell binding to extracellular matrix produces changes in cell shape. We focused on the initial process of cell spreading that follows cell attachment to matrix and, thus, cell ‘shape’ changes are defined here in terms of alterations in projected cell areas, as determined by computerized image analysis. Cell spreading kinetics and changes in microtubule and actin microfilament mass were simultaneously quantitated in hepatocytes plated on different extracellular matrix substrata. The initial rate of cell spreading was highly dependent on the matrix coating density and decreased from 740 microns 2/h to 50 microns 2/h as the coating density was lowered from 1000 to 1 ng/cm2. At approximately 4 to 6 hours after plating, this initial rapid spreading rate slowed and became independent of the matrix density regardless of whether laminin, fibronectin, type I collagen or type IV collagen was used for cell attachment. Analysis of F-actin mass revealed that cell adhesion to extracellular matrix resulted in a 20-fold increase in polymerized actin within 30 minutes after plating, before any significant change in cell shape was observed. This was followed by a phase of actin microfilament disassembly which correlated with the most rapid phase of cell extension and ended at about 6 hours; F-actin mass remained relatively constant during the slow matrix-independent spreading phase. Microtubule mass increased more slowly in spreading cells, peaking at 4 hours, the time at which the transition between rapid and slow spreading rates was observed. However, inhibition of this early rise in microtubule mass using either nocodazole or cycloheximide did not prevent this transition. Use of cytochalasin D revealed that microfilament integrity was absolutely required for hepatocyte spreading whereas interference with microtubule assembly (using nocodazole or taxol) or protein synthesis (using cycloheximide) only partially suppressed cell extension. In contrast, cell spreading could be completely inhibited by combining suboptimal doses of cytochalasin D and nocodazole, suggesting that intact microtubules can stabilize cell form when the microfilament lattice is partially compromised. The physiological relevance of the cytoskeleton and cell shape in hepatocyte physiology was highlighted by the finding that a short exposure (6 hour) of cells to nocodazole resulted in production of smaller cells 42 hours later that exhibited enhanced production of a liver-specific product (albumin). These data demonstrate that spreading and flattening of the entire cell body is not driven directly by net polymerization of either microfilaments or microtubules.(ABSTRACT TRUNCATED AT 400 WORDS)
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Brown, Daniel R., Sophie Helaine, Etienne Carbonnelle, and Vladimir Pelicic. "Systematic Functional Analysis Reveals That a Set of Seven Genes Is Involved in Fine-Tuning of the Multiple Functions Mediated by Type IV Pili in Neisseria meningitidis." Infection and Immunity 78, no. 7 (May 3, 2010): 3053–63. http://dx.doi.org/10.1128/iai.00099-10.
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ABSTRACT Type IV pili (Tfp), which mediate multiple phenotypes ranging from adhesion to motility, are one of the most widespread virulence factors in bacteria. However, the molecular mechanisms of Tfp biogenesis and associated functions remain poorly understood. One of the underlying reasons is that the roles played by the numerous genes involved in Tfp biology are unclear because corresponding mutants have been studied on a case-by-case basis, in different species, and using different assays, often generating heterogeneous results. Therefore, we have recently started a systematic functional analysis of the genes involved in Tfp biology in a well-characterized clinical isolate of the human pathogen Neisseria meningitidis. After previously studying 16 genes involved in Tfp biogenesis, here we report the characterization of 7 genes that are dispensable for piliation and potentially involved in Tfp biology. Using a battery of assays, we assessed piliation and each of the Tfp-linked functions in single mutants, double mutants in which filament retraction is abolished by a concurrent mutation in pilT, and strains overexpressing the corresponding proteins. This showed that each of the seven genes actually fine-tunes a Tfp-linked function(s), which brings us one step closer to a global view of Tfp biology in the meningococcus.
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Hamann, Gerhard F., Helmut Schröck, Dorothe Burggraf, Nathalie Wunderlich, Martin Liebetrau, and Wolfgang Kuschinsky. "Microvascular Basal Lamina Damage after Embolic Stroke in the Rat: Relationship to Cerebral Blood Flow." Journal of Cerebral Blood Flow & Metabolism 23, no. 11 (November 2003): 1293–97. http://dx.doi.org/10.1097/01.wcb.0000090682.07515.5a.
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Microvascular basal lamina damage has been demonstrated after balloon occlusion of the middle cerebral artery in the nonhuman primate and after intravascular filament occlusion in the rat. The aim of the present study was to investigate in the rat whether microvascular damage can be found in the stroke model of intracarotid clot injection as early as 3 hours after clot injection and whether microvascular damage relates to the level of regional cerebral blood flow (rCBF). Microvascular densities and total stained microvascular areas were determined by immunohistochemistry of collagen type IV in cortex and basal ganglia and automatic video-imaging analysis. rCBF was measured by autoradiography in the same brain areas. Compared with the corresponding areas in the nonischemic hemisphere, a significant loss of microvascular density (−16%) and total stained microvascular areas (−10%) was observed in these areas. The reduction of microvascular basal lamina staining was comparable in all animals and was not related to the value of rCBF when measured 3 hours after onset of embolic stroke. In conclusion, microvascular damage occurs as soon as 3 hours after intracarotid clot injection, even in brain areas in which rCBF has returned to normal values.
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Enemuoh, Emmanuel Ugo, Venkata Gireesh Menta, Abdulaziz Abutunis, Sean O’Brien, Labiba Imtiaz Kaya, and John Rapinac. "Energy and Eco-Impact Evaluation of Fused Deposition Modeling and Injection Molding of Polylactic Acid." Sustainability 13, no. 4 (February 9, 2021): 1875. http://dx.doi.org/10.3390/su13041875.
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There is limited knowledge about energy and carbon emission performance comparison between additive fused deposition modeling (FDM) and consolidation plastic injection molding (PIM) forming techniques, despite their recent high industrial applications such as tools and fixtures. In this study, developed empirical models focus on the production phase of the polylactic acid (PLA) thermoplastic polyester life cycle while using FDM and PIM processes to produce American Society for Testing and Materials (ASTM) D638 Type IV dog bone samples to compare their energy consumption and eco-impact. It was established that energy consumption by the FDM layer creation phase dominated the filament extrusion and PLA pellet production phases, with, overwhelmingly, 99% of the total energy consumption in the three production phases combined. During FDM PLA production, about 95.5% of energy consumption was seen during actual FDM part building. This means that the FDM process parameters such as infill percentage, layer thickness, and printing speed can be optimized to significantly improve the energy consumption of the FDM process. Furthermore, plastic injection molding consumed about 38.2% less energy and produced less carbon emissions per one kilogram of PLA formed parts compared to the FDM process. The developed functional unit measurement models can be employed in setting sustainable manufacturing goals for PLA production.
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Popa, Cristina, Carmen Ciobanu, Simona Iconaru, Miruna Stan, Anca Dinischiotu, Constantin Negrila, Mikael Motelica-Heino, Regis Guegan, and Daniela Predoi. "Systematic investigation and in vitro biocompatibility studies on mesoporous europium doped hydroxyapatite." Open Chemistry 12, no. 10 (October 1, 2014): 1032–46. http://dx.doi.org/10.2478/s11532-014-0554-y.
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AbstractThis paper reports the systematic investigation of europium doped hydroxyapatite (Eu:HAp). A set of complementary techniques, namely Fourier Transform Infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), transmission electron microscopy (TEM) and the Brunauer-Emmett-Teller (BET) technique were used towards attaining a detailed understanding of Eu:HAp. The XPS analysis confirmed the substitution of Ca ions by Eu ions in the Eu:HAp samples. Secondly, Eu:HAp and pure HAp present type IV isotherms with a hysteresis loop at a relative pressure (P/P0) between 0.4 and 1.0, indicating the presence of mesopores. Finally, the in vitro biological effects of Eu:HAp nanoparticles were evaluated by focusing on the F-actin filament pattern and heat shock proteins (Hsp) expression in HEK293 human kidney cell line. Fluorescence microscopy studies of the actin protein revealed no changes of the immunolabelling profile in the renal cells cultured in the presence of Eu:HAp nanoparticles. Hsp60, Hsp70 and Hsp90 expressions measured by Western blot analysis were not affected after 24 and 48 hours exposure. Taken together, these results confirmed the lack of toxicity and the biocompatibility of the Eu:HAp nanoparticles. Consequently, the possibility of using these nanoparticles for medical purposes without affecting the renal function can be envisaged.
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TEKİN, MEHMET, and ŞEMSETTİN CİVELEK. "A taxonomic revision of the genus Anthriscus (Apiaceae) in Turkey." Phytotaxa 302, no. 1 (March 28, 2017): 1. http://dx.doi.org/10.11646/phytotaxa.302.1.1.
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A taxonomic revision of Anthriscus (Apiaceae, tribe Scandiceae) in Turkey was carried out. The genus Anthriscus is represented by four sections and eight taxa, including six species with three non-typical infraspecific taxa in that territory, grouped into four sections: i) A. sect. Anthriscus (A. caucalis var. caucalis and A. tenerrima var. tenerrima); ii) A. sect. Cerefolium (A. cerefolium var. trichocarpa); iii) A. sect. Caroides (A. kotschyi); and iv) A. sect. Cacosciadium (A. lamprocarpa subsp. lamprocarpa, A. lamprocarpa subsp. chelikii, A. sylvestris subsp. sylvestris and A. sylvestris subsp. nemorosa). A new taxon, A. lamprocarpa subsp. chelikii, was found and published as a preliminary result of the present revisionary study. Some new characters such as length of filament and petal, and the ratio of fruit length to its beak length are used in the identification key for the first time. New localities of some taxa were found and their distribution areas are expanded. According to all morphological findings on Turkish Anthriscus, a new description of the genus was carried out. The taxonomic treatments for all taxa include type, synonyms (when present), morphological descriptions, phenology, and distribution areas (worldwide and local), habitats, phytogeographic region, conservation assessment and specimens examined. A new identification key for the sections and all Turkish species of the genus Anthriscus is reported, and illustrations and distribution maps in Turkey are also given for eight taxa.
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García-Pelagio, Karla P., Joaquin Muriel, Andrea O'Neill, Patrick F. Desmond, Richard M. Lovering, Linda Lund, Meredith Bond, and Robert J. Bloch. "Myopathic changes in murine skeletal muscle lacking synemin." American Journal of Physiology-Cell Physiology 308, no. 6 (March 15, 2015): C448—C462. http://dx.doi.org/10.1152/ajpcell.00331.2014.
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Diseases of striated muscle linked to intermediate filament (IF) proteins are associated with defects in the organization of the contractile apparatus and its links to costameres, which connect the sarcomeres to the cell membrane. Here we study the role in skeletal muscle of synemin, a type IV IF protein, by examining mice null for synemin (synm-null). Synm-null mice have a mild skeletal muscle phenotype. Tibialis anterior (TA) muscles show a significant decrease in mean fiber diameter, a decrease in twitch and tetanic force, and an increase in susceptibility to injury caused by lengthening contractions. Organization of proteins associated with the contractile apparatus and costameres is not significantly altered in the synm-null. Elastimetry of the sarcolemma and associated contractile apparatus in extensor digitorum longus myofibers reveals a reduction in tension consistent with an increase in sarcolemmal deformability. Although fatigue after repeated isometric contractions is more marked in TA muscles of synm-null mice, the ability of the mice to run uphill on a treadmill is similar to controls. Our results suggest that synemin contributes to linkage between costameres and the contractile apparatus and that the absence of synemin results in decreased fiber size and increased sarcolemmal deformability and susceptibility to injury. Thus synemin plays a moderate but distinct role in fast twitch skeletal muscle.
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Zhang, Xuefang, Guangming Cao, Xiaoli Diao, Wenyu Bai, Yang Zhang, and Shuzhen Wang. "Vimentin Protein In Situ Expression Predicts Less Tumor Metastasis and Overall Better Survival of Endometrial Carcinoma." Disease Markers 2022 (March 14, 2022): 1–12. http://dx.doi.org/10.1155/2022/5240046.
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Background. Vimentin, a cytoplasmic intermediate filament protein, has been recently identified to be a prognostic biomarker in some cancers. However, the function of vimentin in endometrial carcinoma (EC) remains unclear. Our study aimed at evaluating vimentin expression in EC and preliminarily exploring the role of vimentin in EC progression. Methods. In total, 341 EC patients who underwent surgical follow-up were enrolled in the retrospective study. Vimentin expression levels in EC tissues were analyzed using immunohistochemistry. Furthermore, the vimentin (VIM) gene expression levels in 547 samples in The Cancer Genome Atlas (TCGA) were analyzed. To examine the prognostic value of vimentin in EC, Kaplan-Meier survival analysis was performed, and a Cox model was established. Gene set enrichment analysis (GSEA) was also conducted using the Kyoto Encyclopedia of Genes and Genomes (KEGG) database to explore the role of vimentin in EC progression. Results. Negative vimentin expression in EC correlated significantly with lymph node metastasis, deep myometrium invasion (MI), lymph vascular space invasion (LVSI), advanced Federation International of Gynecology and Obstetrics Association (FIGO) stages (III and IV), and high tumor grade. Vimentin negativity was more common in type 2 EC than that in type 1 EC, and vimentin-negative patients had poorer overall survival compared with vimentin-positive patients. The results of GSEA suggested that vimentin may interact with classical pathways in EC. Conclusions. Negative vimentin expression correlates with tumor metastasis and worse overall survival in EC, suggesting that it may be an excellent prognostic biomarker for this disease. The mechanism by which vimentin contributes to EC progression needs to be explored in the future.
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Inoue, S. "Possible continuity of subplasmalemmal cytoplasmic network with basement membrane cord network: ultrastructural study." Journal of Cell Science 108, no. 5 (May 1, 1995): 1971–76. http://dx.doi.org/10.1242/jcs.108.5.1971.
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The ultrastructure of the subplasmalemmal cytoplasm of the cell and the associated basement membrane as well as the area of the cell-basement membrane border were observed with high resolution electron microscopy after preparation of the tissues with cryofixation or glutaraldehyde fixation followed by freeze substitution. The subplasmalemmal cytoplasm of the smooth muscle cells of rat epididymal tubules and the podocyte processes of the mouse glomerular visceral epithelium were found to be composed of a fine network of irregular anastomosing strands. This network closely resembled the previously characterized cord network of the basement membrane. The cords are known to be composed of a 1.5 to 3 nm thick core filament made up of type IV collagen which is surrounded by an irregular ‘sheath’ of other components. The strands in the subplasmalemmal network showed ultrastructural features similar to those of the cord network. Ribbon-like, 4.5 nm wide heparan sulfate proteoglycan ‘double tracks’ were previously reported to be associated with the cord network. Structures similar in size and appearance to the double tracks were also found in the subplasmalemmal network. At the cell-basement membrane border, the lamina densa of the basement membrane was in contact with the cell without the intervening space of a lamina lucida which was recently found to be an artefact caused by conventional tissue processing. Furthermore, the subplasmalemmal network appeared to be continuous through the plasma membrane, with the cord network of the basement membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
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Mangan, Erin K., Jaleh Malakooti, Anthony Caballero, Paul Anderson, Bert Ely, and James W. Gober. "FlbT Couples Flagellum Assembly to Gene Expression in Caulobacter crescentus." Journal of Bacteriology 181, no. 19 (October 1, 1999): 6160–70. http://dx.doi.org/10.1128/jb.181.19.6160-6170.1999.
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ABSTRACT The biogenesis of the polar flagellum of Caulobacter crescentus is regulated by the cell cycle as well as by atrans-acting regulatory hierarchy that functions to couple flagellum assembly to gene expression. The assembly of early flagellar structures (MS ring, switch, and flagellum-specific secretory system) is required for the transcription of class III genes, which encode the remainder of the basal body and the external hook structure. Similarly, the assembly of class III gene-encoded structures is required for the expression of the class IV flagellins, which are incorporated into the flagellar filament. Here, we demonstrate that mutations inflbT, a flagellar gene of unknown function, can restore flagellin protein synthesis and the expression offljK::lacZ (25-kDa flagellin) protein fusions in class III flagellar mutants. These results suggest that FlbT functions to negatively regulate flagellin expression in the absence of flagellum assembly. Deletion analysis shows that sequences within the 5′ untranslated region of the fljK transcript are sufficient for FlbT regulation. To determine the mechanism of FlbT-mediated regulation, we assayed the stability of fljKmRNA. The half-life (t 1/2) of fljKmRNA in wild-type cells was approximately 11 min and was reduced to less than 1.5 min in a flgE (hook) mutant. A flgE flbT double mutant exhibited an mRNA t 1/2of greater than 30 min. This suggests that the primary effect of FlbT regulation is an increased turnover of flagellin mRNA. The increasedt 1/2 of fljK mRNA in aflbT mutant has consequences for the temporal expression offljK. In contrast to the case for wild-type cells,fljK::lacZ protein fusions in the mutant are expressed almost continuously throughout the C. crescentus cell cycle, suggesting that coupling of flagellin gene expression to assembly has a critical influence on regulating cell cycle expression.
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Amenta, P. S., J. Gil, and A. Martinez-Hernandez. "Connective tissue of rat lung. II: Ultrastructural localization of collagen types III, IV, and VI." Journal of Histochemistry & Cytochemistry 36, no. 9 (September 1988): 1167–73. http://dx.doi.org/10.1177/36.9.3403967.
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We localized collagen types III, IV, and VI in normal rat lung by light and electron immunohistochemistry. Type IV collagen was present in every basement membrane examined and was absent from all other structures. Although types III and VI had a similar distribution, being present in the interstitium of major airways, blood vessels, and alveolar septa, as in other organs, they had different morphologies. Type III collagen formed beaded fibers, 15-20 nm in diameter, whereas type VI collagen formed fine filaments, 5-10 nm in diameter. Both collagen types were found exclusively in the interstitium, often associated with thick (30-35 nm) cross-banded type I collagen fibers. Occasionally, type III fibers and type VI filaments could be found bridging from the interstitium to the adventitial aspect of some basement membranes. Furthermore, the association of collagen type VI with types I and III and basement membranes suggests that type VI may contribute to integration of the various components of the pulmonary extracellular matrix into a functional unit.
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Steinert, Peter M., Lyuben N. Marekov, and David A. D. Parry. "Molecular Parameters of Type IV α-Internexin and Type IV-Type III α-Internexin-Vimentin Copolymer Intermediate Filaments." Journal of Biological Chemistry 274, no. 3 (January 15, 1999): 1657–66. http://dx.doi.org/10.1074/jbc.274.3.1657.
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