RESUMO
Objective: The challenges of an aging population worldwide are the increased number of people needing medical and nursing care and inadequate medical resources. Information and communication technologies have progressed remarkably, leading to innovations in various areas. 5G communication systems are capable of high-capacity, high-speed communication with low latency and are expected to transform medicine. We aimed to report a demonstration experiment of telerehabilitation and telemedicine using a mobile ultrasound system in a depopulated area in a mountainous terrain, where 32% of the population are 65 years or older. Methods: At the core hospital, a physician or physical therapist remotely performed ultrasonography or rehabilitation on a subject in a clinic. Five general residents participated in the telerehabilitation as subjects. The delay time and video quality transmitted with 5G and long-term evolution (LTE) communication systems were compared. The physician or physical therapist subjectively evaluated the quality and delay of the transmitted images and subject acceptability. Results: Of seven physical therapists, six and three responded that the video quality was "good" for telerehabilitation with 5G/4K resolution and LTE, respectively. Five physical therapists and one physical therapist reported that the delay time was "acceptable" with 5G/4K resolution and LTE, respectively. For telemedicine using a mobile ultrasound system, the responses for 5G were "the delay was acceptable" and "rather acceptable." In contrast, both respondents' responses for LTE were "not acceptable." Conclusions: Multiple high-definition images can be transmitted with lower latency in telerehabilitation and telemedicine using mobile ultrasound imaging systems with a 5G communication system. These differences affected the subjective evaluation of the doctors and physical therapists.
RESUMO
AIMS: This study aimed to ascertain the number of patients with chronic myelogenous leukemia (CML) and transplant-ineligible patients with multiple myeloma (MM) not recommended by their physicians for optimal drug treatment or who refuse, discontinue, reduce, or skip treatment owing to cost in Japan. METHODS: A cross-sectional survey was conducted among hematologists, hematologic oncologists, and oncologists in Japan treating ≥1 patient with CML or ≥5 transplant-ineligible patients with MM per year. RESULTS: A total of 212 physicians participated: 105 treating patients with CML and 107 treating transplant-ineligible patients with MM. While treatment cost did not lead to non-optimal treatment most patients, physicians reported that they recommended non-optimal treatment to 6.53% of their patients with CML and 1.41% of their transplant-ineligible patients with MM, that 1.51 and 0.35% of their patients, respectively, refused treatment and that 1.97 and 0.71% discontinued treatment owing to treatment cost. However, no significant differences in the effect of treatment cost on recommendation, discontinuation, refusal, or reduction of treatment were observed. Non-recommendation of optimal treatment owing to treatment cost was most common for third-line CML and fourth-line transplant-ineligible MM treatment. Discontinuation due to treatment cost was most common in third-line treatment for both. CONCLUSION: Our results show that non-optimal treatment due to treatment cost occurs among some physicians in Japan for patients with CML and transplant-ineligible patients with MM, but it may be limited to a small percentage of patients. Further research is needed to identify the drivers of treatment decisions for physicians and patients, including those involving treatment cost.
Assuntos
Leucemia Mielogênica Crônica BCR-ABL Positiva , Mieloma Múltiplo , Estudos Transversais , Humanos , Japão , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Mieloma Múltiplo/tratamento farmacológico , Inibidores de Proteínas Quinases/uso terapêuticoRESUMO
Eight strains characterised as Gram-stain-positive, non-spore-forming and non-motile rods were isolated from samples collected from stone chambers of the Takamatsuzuka and Kitora tumuli in Asuka village, Nara Prefecture, Japan. Among them, one strain, T7528-3-6bT, was shown to form a novel lineage within the genus Microbacterium. The most closely phylogenetically related species to T7528-3-6bT was Microbacterium panaciterrae, with 97.8â% sequence similarity. The major isoprenoid quinones of T7528-3-6bT were MK-12, MK-13 and MK-11. The predominant cellular fatty acids for this isolate were anteiso-C15â:â0, anteiso-C17â:â0, iso-C16â:â0 and iso-C15â:â0. The diagnostic diamino acid of the peptidoglycan of this isolate was ornithine. Major polar lipids of the isolate were phosphatidylglycerol, diphosphatidylglycerol and an unknown glycolipid. The G+C content of the genomic DNA of this isolate was 70.1 mol%. On the basis of the results of physiological, biochemical and chemotaxonomic tests and molecular phylogenetic analysis, T7528-3-6bT is considered to represent a novel species of the genus Microbacterium, for which the name M. tumbae sp. nov. has been proposed. The type strain is T7528-3-6bT (=JCM 28836T=NCIMB 15039T). The results of comparisons of both phenotypic and genotypic (16S rRNA gene sequence) characteristics indicated that the remaining seven isolates were very closely related to Microbacterium shaanxiense. Although the sequence similarity between the two was 99.2â%, further detailed multifaceted comparisons are needed to determine their accurate taxonomic assignment.
Assuntos
Actinomycetales/classificação , Filogenia , Microbiologia do Solo , Actinomycetales/genética , Actinomycetales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Glicolipídeos/química , Japão , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/químicaRESUMO
RhoA-mediated regulation of myosin-II activity in the actin cortex controls the ability of cells to contract and bleb during a variety of cellular processes, including cell migration and division. Cell contraction and blebbing also frequently occur as part of the cytopathic effect seen during many different viral infections. We now demonstrate that the vaccinia virus protein F11, which localizes to the plasma membrane, is required for ROCK-mediated cell contraction from 2 hr post infection. Curiously, F11-induced cell contraction is dependent on RhoC and not RhoA signaling to ROCK. Moreover, RhoC-driven cell contraction depends on the upstream inhibition of RhoD signaling by F11. This inhibition prevents RhoD from regulating its downstream effector Pak6, alleviating the suppression of RhoC by the kinase. Our observations with vaccinia have now demonstrated that RhoD recruits Pak6 to the plasma membrane to antagonize RhoC signaling during cell contraction and blebbing.
Assuntos
Movimento Celular/fisiologia , Quinases Ativadas por p21/metabolismo , Proteínas rho de Ligação ao GTP/metabolismo , Actinas/metabolismo , Linhagem Celular Tumoral , Humanos , Transdução de Sinais , Proteína rhoA de Ligação ao GTP/metabolismo , Proteína de Ligação a GTP rhoCRESUMO
Microbial outbreaks and related biodeterioration problems have affected the 1300-year-old multicolor (polychrome) mural paintings of the special historic sites Takamatsuzuka Tumulus (TT) and Kitora Tumulus (KT). Those of TT are designated as a national treasure. The microbiomes of these tumuli, both located in Asuka village, Nara, Japan, are critically reviewed as the central subject of this report. Using culture-dependent methods (conventional isolation and cultivation), we conducted polyphasic studies of the these microbial communities and identified the major microbial colonizers (Fusarium spp., Trichoderma spp., Penicillium spp., dark Acremonium spp., novel Candida yeast spp., Bacillus spp., Ochrobactrum spp., Stenotrophomonas tumulicola, and a few actinobacterial genera) and noteworthy microbial members (Kendrickiella phycomyces, Cephalotrichum verrucisporum (≡Doratomyces verrucisporus), Sagenomella striatispora, Sagenomella griseoviridis, two novel Cladophialophora spp., Burgoa anomala, one novel species Prototheca tumulicola, five novel Gluconacetobacter spp., three novel Bordetella spp., and one novel genus and species Krasilnikoviella muralis) involved in the biodeterioration of mural paintings, plaster walls, and stone chamber interiors. In addition, we generated microbial community data from TT and KT samples using culture-independent methods (molecular biological methods, including PCR-DGGE, clone libraries, and pyrosequence analysis). These data are comprehensively presented, in contrast to those derived from culture-dependent methods. Furthermore, the microbial communities detected using both methods are analytically compared, and, as a result, the complementary roles of these methods and approaches are highlighted. In related contexts, knowledge of similar biodeterioration problems affecting other prehistoric cave paintings, mainly at Lascaux in France and Altamira in Spain, are referred to and commented upon. Based on substrate preferences (or ecological grouping) and mapping (plotting detection sites of isolates), we speculate on the possible origins and invasion routes whereby the major microbial colonizers invaded the TT stone chamber interior. Finally, concluding remarks, lessons, and future perspectives based on our microbiological surveys of these ancient tumuli, and similar treasures outside of Japan, are briefly presented. A list of the microbial taxa that have been identified and fully or briefly described by us as known and novel taxa for TT and KT isolates since 2008 is presented in Supplementary Materials.
Assuntos
Bactérias/classificação , Fungos/classificação , Microbiota , Pinturas , Bactérias/isolamento & purificação , Biodegradação Ambiental , DNA Bacteriano/isolamento & purificação , DNA Fúngico/isolamento & purificação , Fungos/isolamento & purificação , Japão , Filogenia , Reação em Cadeia da Polimerase , RNA Ribossômico 16S/isolamento & purificação , Análise de Sequência de DNARESUMO
A Gram-stain-positive, facultatively anaerobic actinomycete, designated strain T6220-5-2bT, was isolated from a sample taken from a mouldy spot on the surface of a mural painting (the white tiger, Byakko) inside the stone chamber of Takamatsuzuka Tumulus in Asuka village, Nara Prefecture, Japan. Based on 16S rRNA gene sequence analysis of the isolate, it was closely related to the genus Promicromonospora, but formed of a novel lineage within the family Promicromonosporaceae. The closest related species to strain T6220-5-2bT was Promicromonospora flava, with which it shared 99.1â% 16S rRNA gene sequence similarity. The isoprenoid quinone systems were menaquinones MK-9(H2), MK-9(H0) and MK-9(H4). The predominant cellular fatty acids for the isolate were anteiso-C15 : 0 and iso-C15 : 0. The peptidoglycan contained glutamic acid, aspartic acid, alanine and lysine, with the last named being the diagnostic diamino acid. The cell-wall acyl type was acetyl. The major polar lipids of the isolate were phosphatidylglycerol, diphosphatidylglycerol, phosphatidylinositol, phosphatidylinositolmannoside, two unknown phospholipids and an unknown phosphoglycolipid. Whole-cell sugars of the isolate were galactose, glucose and ribose. The DNA G+C content of the genomic DNA was 75.2 mol%. Based on the results of phylogenetic, physiological and biochemical analyses and DNA-DNA hybridization experiments, the isolate was considered to represent a novel species of a new genus in the family Promicromonosporaceae, for which the name Krasilnikoviella muralis gen. nov., sp. nov. is proposed. The type strain of Krasilnikoviella muralis is T6220-5-2bT (=JCM 28789T=NCIMB 15040T). The reclassification of Promicromonospora flava as Krasilnikoviella flava comb. nov. is also proposed with the emended description of this species.
Assuntos
Actinomycetales/classificação , Pinturas , Filogenia , Actinomycetales/genética , Actinomycetales/isolamento & purificação , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Japão , Hibridização de Ácido Nucleico , Peptidoglicano/química , Fosfolipídeos/química , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
During investigation of the biological contamination of the 1300-year-old mural paintings and plaster walls inside the stone chambers of the Takamatsuzuka and Kitora Tumuli (TT and KT) in Asuka-mura, Nara Prefecture, Japan, the identity of 17 bacterial isolates from blackish mouldy spots and viscous gels (biofilms) collected from both tumuli (16 isolates from TT and one from KT) during our 2005-2007 microbiological survey was systematically elucidated. One cluster of the major bacterial isolates was assigned to the genus Stenotrophomonas (class Gammaproteobacteria) by phylogenetic analysis of the 16S rRNA gene sequences. These isolates were divided into two groups A and B. Group A comprised 15 TT isolates that took a phylogenetic position near Stenotrophomonas chelatiphaga LPM-5T. Based on our analysis of the phenotypic (cultural, morphological, physiological and chemotaxonomic) characteristics and genotypic/molecular characteristics (DNA base composition, DNA-DNA relatedness, and 16S rRNA and gyrB gene sequences), the novel species name Stenotrophomonas tumulicola sp. nov. is proposed for the group A isolates with the type strain T5916-2-1bT ( = JCM 30961T = NCIMB 15009T). Group B, which contained only one TT and one KT isolate, was closely related to [Pseudomonas] geniculata, [P.] hibiscicola, [P.] beteli, Stenotrophomonas maltophilia and Stenotrophomonas pavanii. The two isolates were genotypically and phenotypically assignable to S. maltophilia.
RESUMO
Ten strains of Gram-stain-negative, non-spore-forming, non-motile coccobacilli were isolated from the plaster wall surface of 1300-year-old mural paintings inside the stone chamber of the Takamatsuzuka tumulus in Asuka village (Asuka-mura), Nara Prefecture, Japan. Based on 16S rRNA gene sequence analysis of the isolates, they belonged to the proteobacterial genus Bordetella (class Betaproteobacteria) and could be separated into three groups representing novel lineages within the genus Bordetella. Three isolates were selected, one from each group, and identified carefully using a polyphasic approach. The isolates were characterized by the presence of Q-8 as their major ubiquinone system and C16 : 0 (30.0-41.8 %), summed feature 3 (C16 : 1ω7c and/or C16 : 1ω6c; 10.1-27.0 %) and C17 : 0 cyclo (10.8-23.8 %) as the predominant fatty acids. The major hydroxy fatty acids were C12 : 0 2-OH and C14 : 0 2-OH. The DNA G+C content was 59.6-60.0 mol%. DNA-DNA hybridization tests confirmed that the isolates represented three separate novel species, for which the names Bordetella muralis sp. nov. (type strain T6220-3-2bT = JCM 30931T = NCIMB 15006T), Bordetella tumulicola sp. nov. (type strain T6517-1-4bT = JCM 30935T = NCIMB 15007T) and Bordetella tumbae sp. nov. (type strain T6713-1-3bT = JCM 30934T = NCIMB 15008T) are proposed. These results support previous evidence that members of the genus Bordetella exist in the environment and may be ubiquitous in soil and/or water.
Assuntos
Bordetella/classificação , Pinturas , Filogenia , Arqueologia , Técnicas de Tipagem Bacteriana , Composição de Bases , Bordetella/genética , Bordetella/isolamento & purificação , DNA Bacteriano/genética , Ácidos Graxos/química , Japão , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/químicaRESUMO
A phylogenetically novel proteobacterium, strain Shr3(T), was isolated from sand gravels collected from the eastern margin of the Sahara Desert. The isolation strategy targeted bacteria filterable through 0.2-µm-pore-size filters. Strain Shr3(T) was determined to be a Gram-negative, aerobic, non-motile, filamentous bacterium. Oxidase and catalase reactions were positive. Strain Shr3(T) showed growth on R2A medium, but poor or no growth on nutrient agar, trypticase soy agar and standard method agar. The major isoprenoid quinone was menaquinone-7. The dominant cellular fatty acids detected were C16:1ω5c and C16:0, and the primary hydroxy acid present was C12:0 3-OH. The DNA G+C content was 54.0 mol%. Phylogenetic analysis based on 16S rRNA gene sequences revealed that strain Shr3(T) was affiliated with an uncultivated lineage of the phylum Proteobacteria; the nearest known type strain, with 83% sequence similarity, was Desulfomicrobium orale DSM 12838(T) in the class Deltaproteobacteria. The isolate and closely related environmental clones formed a novel class-level clade in the phylum Proteobacteria with high bootstrap support (96-99%). Based on these results, the novel class Oligoflexia classis nov. in the phylum Proteobacteria and the novel genus and species Oligoflexus tunisiensis gen. nov., sp. nov. are proposed for strain Shr3(T), the first cultivated representative of the Oligoflexia. The type strain of Oligoflexus tunisiensis is Shr3(T) ( = JCM 16864(T) = NCIMB 14846(T)). We also propose the subordinate taxa Oligoflexales ord. nov. and Oligoflexaceae fam. nov. in the class Oligoflexia.
Assuntos
Filogenia , Proteobactérias/classificação , Microbiologia do Solo , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Clima Desértico , Ácidos Graxos/química , Bactérias Gram-Negativas/classificação , Dados de Sequência Molecular , Proteobactérias/genética , Proteobactérias/isolamento & purificação , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Tunísia , Vitamina K 2/análogos & derivados , Vitamina K 2/químicaRESUMO
A carbon-felt-based multi-enzyme immobilized bioanode for biofuel cells has been successfully developed. The combination of four enzymes, namely, invertase, mutarotase, glucose oxidase, and fructose dehydrogenase, makes it possible to use sucrose--a disaccharide--as fuel for the bioanode. The new electrode exhibits a high oxidation current density of about 12 mA cm(-2) (0.25 V vs. Ag/AgCl) in a McIlvaine buffer solution containing sucrose at pH 6.0 in the half-cell configuration. A sucrose/O(2) biofuel cell composed of the bioanode and an opposite biocathode, including bilirubin oxidase as the enzymatic electrocatalyst, was fabricated, and the new device demonstrated a maximum power density of 2.90 mW cm(-2) with an open-circuit voltage of 0.69 V in the McIlvaine buffer solution. The biofuel cell fabricated using our multi-enzyme anode operates in commercially available beverages that contain only sugar, even without glucose.
Assuntos
Carbono/química , Enzimas Imobilizadas/química , Sacarose/química , Fontes de Energia Bioelétrica , Carboidratos Epimerases/química , Eletrodos , Frutose/química , Glucose/química , Glucose Oxidase/química , Nanotubos de Carbono/química , Oxirredução , Oxirredutases/química , Oxirredutases atuantes sobre Doadores de Grupo CH-CH/química , Oxigênio/química , beta-Frutofuranosidase/químicaRESUMO
The vaccinia F11 protein promotes viral spread by modulating the cortical actin cytoskeleton by inhibiting RhoA signaling via an unknown mechanism. PDZ domains are widely conserved protein interaction modules whose occurrence in viral proteins is unprecedented. We found that F11 contains a central PDZ-like domain that is required to downregulate RhoA signaling and enhance viral spread. The PDZ-like domain interacts with the PDZ binding motif of the Rho GTPase-activating protein (GAP) Myosin-9A. In the absence of Myosin-9A, RhoA signaling is not inhibited, resulting in fewer actin tails and reduced virus release concomitant with less viral spread. The loss of Myosin-9A GAP activity or its ability to bind F11 also reduces actin tail formation. Furthermore, the ability of Myosin-9A to promote viral spread depends on F11 binding RhoA. Thus, F11 acts as a functional PDZ-containing scaffolding protein to inhibit RhoA signaling by binding Myosin-9A.
Assuntos
Miosinas/metabolismo , Transdução de Sinais , Vaccinia virus/metabolismo , Vacínia/enzimologia , Proteínas Virais/metabolismo , Proteína rhoA de Ligação ao GTP/metabolismo , Regulação para Baixo , Interações Hospedeiro-Patógeno , Humanos , Miosinas/genética , Domínios PDZ , Ligação Proteica , Vacínia/genética , Vacínia/virologia , Vaccinia virus/química , Vaccinia virus/genética , Proteínas Virais/química , Proteínas Virais/genética , Proteína rhoA de Ligação ao GTP/genéticaRESUMO
In May 2012, strain HNN-6 (=JCM 18566) , a Gram-negative, non-spore-forming, motile and strictly aerobic rod, which produces a pale orange pigment, was isolated from a hot spring water sample obtained in Kagoshima, Japan, by a plating method using R2A medium at 30°C for 7 d. The 16S rRNA gene sequences (1,437bp) of this strain (accession number: AB731137) had a close similarity (99.1%) to Hydrotalea sandarakina AF-51T (JF739858) . Growth occurred at 25-45°C and pH 5.0-8.0, with optimal growth at 40°C and pH 6.0-7.0. Growth did not occur in the presence of â§2% NaCl. The API 20NE identification system gave positive results for nitrate, aesculin, gelatin, 4-nitrophenyl-ß-D-galactopyranoside, D-glucose, D-mannose, maltose and oxidase (API code number 1472204) . The dominant cellular fatty acids of strain HNN-6 were iso-C15:0 (32.6%) , iso-C17:0 3-OH (24.2%) and iso-C16:0 (8.4%) . The guanine-plus-cytosine (G+C) content of DNA was 36.2 mol%. This article is the first report to describe the characteristics of an orange-pigmented bacterium isolated from a hot spring water sample in Japan.
Assuntos
Bactérias/isolamento & purificação , Fontes Termais/microbiologia , Pigmentos Biológicos/metabolismo , Bactérias/classificação , Bactérias/genética , Bactérias/metabolismo , Composição de Bases , Ácidos Graxos/metabolismo , Japão , Dados de Sequência Molecular , FilogeniaRESUMO
Ten strains of Gram-stain-negative, rod-shaped, non-spore-forming bacteria were isolated from the burial mound soil collected before the dismantling and samples collected during the dismantling work on the Takamatsuzuka Tumulus in Asuka village, Nara Prefecture, Japan in 2007. On the basis of the 16S rRNA gene sequence analysis of the isolates, they were accommodated in the genus Gluconacetobacter (class Alphaproteobacteria) and can be separated into four groups within the cluster containing the genus Gluconacetobacter. One of the groups demonstrated a phylogenetic position identical to that of Gluconacetobacter asukensis, which was isolated from small holes on plaster walls of the stone chamber interior of Kitora Tumulus in Asuka village, Nara Prefecture, Japan. The remaining three groups consisted of novel lineages within the genus Gluconacetobacter. A total of four isolates were selected from each group and carefully identified using a polyphasic approach. The isolates were characterized on the basis of their possessing Q-10 as the major ubiquinone system and C18â:â1ω7c (58.5-65.2â%) as the predominant fatty acid. A DNA-DNA hybridization test was used to determine that the three lineages represented novel species, for which the names Gluconacetobacter tumulisoli sp. nov., Gluconacetobacter takamatsuzukensis sp. nov. and Gluconacetobacter aggeris sp. nov. are proposed. The type strains are T611xx-1-4a(T) (â=âJCM 19097(T)â=âNCIMB 14861(T)), T61213-20-1a(T) (â=âJCM 19094(T)â=âNCIMB 14859(T)) and T6203-4-1a(T) (â=âJCM 19092(T)â=âNCIMB 14860(T)), respectively.
Assuntos
Gluconacetobacter/classificação , Filogenia , Microbiologia do Solo , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/química , Gluconacetobacter/genética , Gluconacetobacter/isolamento & purificação , Japão , Dados de Sequência Molecular , Hibridização de Ácido Nucleico , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/químicaRESUMO
Six Gram-negative, rod-shaped, non-spore-forming bacterial strains were isolated from small holes on plaster walls of the stone chamber interior of the Kitora Tumulus in Asuka village, Nara Prefecture, Japan. These were investigated by means of a polyphasic approach. All the isolates were strictly aerobic and motile by peritrichous flagella. Phylogenetic trees generated based on 16S rRNA gene sequences identified two novel lineages (comprising five isolates and one isolate, respectively) within the genus Gluconacetobacter. The isolates were characterized by having Q-10 as the major ubiquinone system and C(18:1)ω7c (58.7-63.1% of the total) as the predominant fatty acid. DNA-DNA hybridization experiments endorsed the species rank for the two lineages, for which the names Gluconacetobacter tumulicola sp. nov. (type strain K5929-2-1b(T)â=âJCM 17774(T)â=âNCIMB 14760(T)) and Gluconacetobacter asukensis sp. nov. (type strain K8617-1-1b(T)â=âJCM 17772(T)â=âNCIMB 14759(T)) are proposed.
Assuntos
Gluconacetobacter/classificação , Pinturas , Filogenia , Técnicas de Tipagem Bacteriana , Composição de Bases , DNA Bacteriano/genética , Ácidos Graxos/análise , Gluconacetobacter/genética , Gluconacetobacter/isolamento & purificação , Japão , Dados de Sequência Molecular , RNA Ribossômico 16S/genética , Análise de Sequência de DNA , Ubiquinona/análogos & derivados , Ubiquinona/análiseRESUMO
When Shigella infect the intestinal epithelium, they deliver several effectors through the type III secretion system (T3SS) into the surrounding space and directly into the host-cell cytoplasm, where they can mimic and usurp host cellular functions or subvert host-cell signalling pathways and the immune response. Although bacterial strategies and mechanisms of infection vary greatly, recent studies of Shigella effectors have revealed that Shigella possess a highly evolved strategy for infection.
Assuntos
Disenteria Bacilar/microbiologia , Enteropatias/microbiologia , Shigella/fisiologia , Animais , Proteínas de Bactérias/fisiologia , Interações Hospedeiro-Patógeno , Humanos , Mucosa Intestinal/microbiologia , Shigella/patogenicidadeAssuntos
Actinas/metabolismo , Bactérias/patogenicidade , Endocitose/fisiologia , Proteínas de Membrana/metabolismo , Adenosina Trifosfatases/metabolismo , Animais , Bactérias/metabolismo , Clatrina/fisiologia , Citoesqueleto/metabolismo , Proteínas Ativadoras de GTPase/fisiologia , Humanos , Ligação Proteica , Transporte Proteico , Transdução de Sinais/fisiologia , Fatores de Virulência/metabolismo , Fatores de Virulência/fisiologiaRESUMO
Shigella use a special mechanism to invade epithelial cells called 'the trigger mechanism of entry', which allows epithelial cells to trap several bacteria simultaneously. On contact, Shigella deliver effectors into epithelial cells through the type III secretion system. Here, we show that one of the effectors, IpgB1, has a pivotal role in producing membrane ruffles by exploiting the RhoG-ELMO-Dock180 pathway to stimulate Rac1 activity. Using pulldown assays, we identified engulfment and cell motility (ELMO) protein as the IpgB1 binding partner. IpgB1 colocalized with ELMO and Dock180 in membrane ruffles induced by Shigella. Shigella invasiveness and IpgB1-induced ruffles were less in ELMO- and Dock180-knockdown cells compared with wild-type cells. Membrane association of ELMO-Dock180 with ruffles were promoted when cells expressed an IpgB1-ELMO chimera, establishing that IpgB1 mimics the role of RhoG in producing membrane ruffles. Taken together, our findings show that IpgB1 mimicry is the key to invasion by Shigella.
Assuntos
Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Aderência Bacteriana , Shigella/patogenicidade , Proteínas rac de Ligação ao GTP/metabolismo , Proteínas rac1 de Ligação ao GTP/metabolismo , Proteínas Adaptadoras de Transdução de Sinal/genética , Animais , Linhagem Celular , Membrana Celular/metabolismo , Cães , Células HeLa , Humanos , Imunoprecipitação , Camundongos , Modelos Biológicos , Células NIH 3T3 , Transporte Proteico , Interferência de RNA , Shigella/fisiologia , Transdução de Sinais , Transdução Genética , Transfecção , Proteínas rac de Ligação ao GTP/genética , Proteínas rac1 de Ligação ao GTP/fisiologiaRESUMO
Some pathogenic bacteria actually invade the cytoplasm of their target host cells. Invasive bacteria acquire the propulsive force to move by recruiting actin and inducing its polymerization. Here we show that Shigella movement within the cytoplasm was severely hindered by microtubules and that the bacteria destroyed surrounding microtubules by secreting VirA by means of the type III secretion system. Degradation of microtubules by VirA was dependent on its alpha-tubulin-specific cysteine protease-like activity. virA mutants did not move within the host cytoplasm and failed to move into adjacent cells.
Assuntos
Cisteína Endopeptidases/metabolismo , Citoplasma/microbiologia , Microtúbulos/metabolismo , Shigella flexneri/fisiologia , Shigella flexneri/patogenicidade , Tubulina (Proteína)/metabolismo , Fatores de Virulência/metabolismo , Actinas/metabolismo , Animais , Células COS , Chlorocebus aethiops , Disenteria Bacilar/microbiologia , Camundongos , Camundongos Endogâmicos C57BL , Microscopia de Fluorescência , Microtúbulos/efeitos dos fármacos , Microtúbulos/ultraestrutura , Movimento , Mutação , Nocodazol/farmacologia , Shigella flexneri/enzimologia , Shigella flexneri/genéticaRESUMO
Enterohaemorrhagic Escherichia coli (EHEC) contains a 36-kb pathogenicity island termed the locus of enterocyte effacement (LEE), which encodes a type III secretion system (TTSS) and virulence proteins. In this paper, we show that the O157:H7 Sakai clpPX mutant strongly impaired the secretion of virulence proteins by TTSS and repressed transcription from all the LEE promoters. The rpoS mutation in O157:H7 Sakai enhanced the transcription from all the LEE promoters and the secretion of virulence proteins, and it could partially suppress the defects of the clpPX mutation. These data indicate that the O157:H7 Sakai ClpXP protease is a positive regulator for LEE expression and that this regulation occurs by two pathways: the sigma(S)-dependent and -independent pathways.