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Microbial Ecology Jan 2018Honeybees are prone to parasite and pathogen infestations/infections due to their social colony life. Bacterial pathogens in particular lead to destructive infections of... (Review)
Review
Honeybees are prone to parasite and pathogen infestations/infections due to their social colony life. Bacterial pathogens in particular lead to destructive infections of the brood. European foulbrood is caused by the bacterium Melissococcus plutonius in combination with several other Gram-positive bacteria (Achromobacter eurydice, Bacillus pumilus, Brevibacillus laterosporus, Enterococcus faecalis, Paenibacillus alvei, Paenibacillus dendritiformis) involved as secondary invaders following the initial infection. More than a century ago, A. eurydice was discovered to be associated with European foulbrood and morphologically and biochemically characterized. However, since the 1950s-1960s, only a few studies are known covering the biological relevance of this bacterium. Here, we review the biology, ecology, morphology, and biochemistry and discuss the still unclear systematic classification of A. eurydice.
Topics: Achromobacter; Animals; Bees; Europe; Larva
PubMed: 28634639
DOI: 10.1007/s00248-017-1007-x -
Biotechnology Advances 2012The microbial production of polyhydroxybutyrate (PHB) is a complex process in which the final quantity and quality of the PHB depend on a large number of process... (Review)
Review
The microbial production of polyhydroxybutyrate (PHB) is a complex process in which the final quantity and quality of the PHB depend on a large number of process operating variables. Consequently, the design and optimal dynamic operation of a microbial process for the efficient production of PHB with tailor-made molecular properties is an extremely interesting problem. The present study investigates how key process operating variables (i.e., nutritional and aeration conditions) affect the biomass production rate and the PHB accumulation in the cells and its associated molecular weight distribution. A combined metabolic/polymerization/macroscopic modelling approach, relating the process performance and product quality with the process variables, was developed and validated using an extensive series of experiments and measurements. The model predicts the dynamic evolution of the biomass growth, the polymer accumulation, the consumption of carbon and nitrogen sources and the average molecular weights of the PHB in a bioreactor, under batch and fed-batch operating conditions. The proposed integrated model was used for the model-based optimization of the production of PHB with tailor-made molecular properties in Azohydromonas lata bacteria. The process optimization led to a high intracellular PHB accumulation (up to 95% g of PHB per g of DCW) and the production of different grades (i.e., different molecular weight distributions) of PHB.
Topics: Alcaligenaceae; Ammonium Sulfate; Biomass; Biopolymers; Bioreactors; Culture Media; Fermentation; Hydroxybutyrates; Kinetics; Models, Biological; Molecular Weight; Polyhydroxyalkanoates; Sucrose
PubMed: 21756991
DOI: 10.1016/j.biotechadv.2011.06.021 -
MBio Oct 2017Nearly all virulence factors in are activated by a master two-component system, BvgAS, composed of the sensor kinase BvgS and the response regulator BvgA. When BvgS is...
Nearly all virulence factors in are activated by a master two-component system, BvgAS, composed of the sensor kinase BvgS and the response regulator BvgA. When BvgS is active, BvgA is phosphorylated (BvgA~P), and virulence-activated genes (s) are expressed [Bvg(+) mode]. When BvgS is inactive and BvgA is not phosphorylated, virulence-repressed genes (s) are induced [Bvg(-) mode]. Here, we have used transcriptome sequencing (RNA-seq) and reverse transcription-quantitative PCR (RT-qPCR) to define the BvgAS-dependent regulon of Tohama I. Our analyses reveal more than 550 BvgA-regulated genes, of which 353 are newly identified. BvgA-activated genes include those encoding two-component systems (such as ), multiple other transcriptional regulators, and the extracytoplasmic function (ECF) sigma factor , which is needed for type 3 secretion system (T3SS) expression, further establishing the importance of BvgA~P as an apex regulator of transcriptional networks promoting virulence. Using transcription, we demonstrate that the promoter for is directly activated by BvgA~P. BvgA-FeBABE cleavage reactions identify BvgA~P binding sites centered at positions -41.5 and -63.5 in Most importantly, we show for the first time that genes for multiple and varied metabolic pathways are significantly upregulated in the Bvg(-) mode. These include genes for fatty acid and lipid metabolism, sugar and amino acid transporters, pyruvate dehydrogenase, phenylacetic acid degradation, and the glycolate/glyoxylate utilization pathway. Our results suggest that metabolic changes in the Bvg(-) mode may be participating in bacterial survival, transmission, and/or persistence and identify over 200 new s that can be tested for function. Within the past 20 years, outbreaks of whooping cough, caused by , have led to respiratory disease and infant mortalities, despite good vaccination coverage. This is due, at least in part, to the introduction of a less effective acellular vaccine in the 1990s. It is crucial, then, to understand the molecular basis of growth and infection. The two-component system BvgA (response regulator)/BvgS (histidine kinase) is the master regulator of virulence genes. We report here the first RNA-seq analysis of the BvgAS regulon in , revealing that more than 550 genes are regulated by BvgAS. We show that genes for multiple and varied metabolic pathways are highly regulated in the Bvg(-) mode (absence of BvgA phosphorylation). Our results suggest that metabolic changes in the Bvg(-) mode may be participating in bacterial survival, transmission, and/or persistence.
Topics: Bacterial Proteins; Bordetella pertussis; Gene Expression Regulation, Bacterial; Genes, Regulator; High-Throughput Nucleotide Sequencing; Promoter Regions, Genetic; Regulon; Reverse Transcriptase Polymerase Chain Reaction; Signal Transduction; Transcription Factors; Transcriptome; Virulence
PubMed: 29018122
DOI: 10.1128/mBio.01526-17 -
Journal of Microbiology (Seoul, Korea) Jul 2020A grey pink colored bacterium, strain t3-1-3, was isolated from the air at the foot of the Xiangshan Mountain in Beijing, China. The cells are aerobic,...
A grey pink colored bacterium, strain t3-1-3, was isolated from the air at the foot of the Xiangshan Mountain in Beijing, China. The cells are aerobic, Gram-stain-negative, non-spore-forming, motile and coccoid-rod shaped (0.9-1.2 × 1.9-2.1 μm). Strain t3-1-3 was catalase-positive and oxidase-negative and this strain grew at 4-42°C (optimum 28°C), a pH of 4.0-9.0 (optimum pH 7.0) and under 0-2% (w/v) NaCl (optimum 0-1% NaCl). A phylogenetic analysis based on 16S rRNA gene sequences revealed that strain t3-1-3 was closely related to Azohydromonas riparia UCM-11 (97.4% similarity), followed by Azohydromonas australica G1-2 (96.8%) and Azohydromonas ureilytica UCM-80 (96.7%). The genome of strain t3-1-3 contains 6,895 predicted protein-encoding genes, 8 rRNA genes, 62 tRNA genes and one sRNA gene, as well as five potential biosynthetic gene clusters, including clusters of genes coding for non-ribosomal peptide synthetase (NRPS), bacteriocin and arylpolyene and two clusters of genes for terpene. The predominant cellular fatty acids (> 10.0% of the total) in strain t3-1-3 were summed feature 3 (Cω7c and/or Cω6c, 37.8%), summed feature 8 (Cω7c and/or Cω6c, 29.7%) and C (17.3%). Strain t3-1-3 contained ubiquinone-8 (Q-8) as the predominant respiratory quinone. The polar lipids of strain t3-1-3 comprised phosphatidyl ethanolamine (PE), phosphatidyl glycerol (PG), diphosphatidyl glycerol (DPG), an unidentified glycolipid (GL), an unidentified aminophospholipid (APL), two unidentified phospholipid (PL1-2) and five unidentified lipid (L1-5). The DNA G + C content of the type strain is 70.3%. The broader range of growth temperature, assimilation of malic acid and trisodium citrate, presence of Cω6c and an unidentified glycolipid and absence of C 2-OH and Ciso differentiate strain t3-1-3 from related species. Based on the taxonomic data presented in this study, we suggest that strain t3-1-3 represents a novel species within the genus Azohydromonas, for which the name Azohydromonas aeria sp. nov. is proposed. The type strain of Azohydromonas aeria is t3-1-3 (= CFCC 13393 = LMG 30135).
Topics: Air Microbiology; Alcaligenaceae; Bacterial Typing Techniques; Bacteriocins; Base Composition; DNA, Bacterial; Fatty Acids; Genome, Bacterial; Phylogeny; RNA, Ribosomal, 16S; Terpenes
PubMed: 32594456
DOI: 10.1007/s12275-020-9423-x -
Clinical Infectious Diseases : An... Jul 2020
Topics: Bordetella Infections; Bordetella parapertussis; Bordetella pertussis; Humans; Whooping Cough
PubMed: 31552410
DOI: 10.1093/cid/ciz842 -
Reviews of Infectious Diseases 1988Bordetella pertussis cells express multiple virulence-associated surface proteins, including adenylate cyclase, agglutinogens 2 and 3, filamentous hemagglutinin,... (Review)
Review
Bordetella pertussis cells express multiple virulence-associated surface proteins, including adenylate cyclase, agglutinogens 2 and 3, filamentous hemagglutinin, pertussis toxin, and outer-membrane protein (Omp) 30/32 and Omp91. Surface proteins that are not virulence-associated include three peptidoglycan-associated Omps of apparent molecular weights 40,000, 25,000, and 18,000. Omp40 is an anion-selective porin and is the most abundant surface protein of virulent and avirulent cells. Three independent approaches--immunomicroscopy, surface radioiodination, and isolation of Triton X-100-insoluble envelope proteins--suggest that the Triton-insoluble fraction of the B. pertussis cell envelope is the outer membrane. Agglutinogens 2 and 3 and filamentous hemagglutinin lie outside the outer membrane, the first two as fimbriae and the last as a microcapsule. Adenylate cyclase and pertussis toxin are present in the outer membrane but may be present transiently or present in small amounts.
Topics: Bacterial Proteins; Bordetella pertussis; Cell Membrane; Membrane Proteins; Virulence
PubMed: 2903539
DOI: 10.1093/cid/10.supplement_2.s327 -
Viruses Oct 2020Bacteriophages (phages), viruses that infect bacteria, are considered to be highly host-specific. To add to the knowledge about the evolution and development of...
Bacteriophages (phages), viruses that infect bacteria, are considered to be highly host-specific. To add to the knowledge about the evolution and development of bacteriophage speciation toward its host, we conducted a 21-day experiment with the broad host-range bacteriophage phage P14. We incubated the phage, which was previously isolated and enriched with the Alphaproteobacteria H14, with the Betaproteobacteria H5. During the experiment, we observed an increase in the phage's predation efficacy towards H5. Furthermore, genome analysis and the comparison of the bacteriophage's whole genome indicated that rather than being scattered evenly along the genome, mutations occur in specific regions. In total, 67% of the mutations with a frequency higher than 30% were located in genes that encode tail proteins, which are essential for host recognition and attachment. As control, we incubated the phage with the Alphaproteobacteria H8. In both experiments, most of the mutations appeared in the gene encoding the tail fiber protein. However, mutations in the gene encoding the tail tubular protein B were only observed when the phage was incubated with H5. This highlights the phage's tail as a key player in its adaptation to different hosts. We conclude that mutations in the phage's genome were mainly located in tail-related regions. Further investigation is needed to fully characterize the adaptation mechanisms of the phage P14.
Topics: Adaptation, Biological; Alcaligenaceae; Amino Acid Sequence; Bacteriophages; Evolution, Molecular; Genetic Variation; Genome, Viral; Host Specificity; Mutation; Phyllobacteriaceae; Viral Tail Proteins
PubMed: 33036277
DOI: 10.3390/v12101132 -
Le Infezioni in Medicina 2016Oligella ureolytica is an emerging bacteria rarely implicated as a human pathogen. It is mostly recovered from urinary and respiratory tract specimens as a commensal... (Review)
Review
Oligella ureolytica is an emerging bacteria rarely implicated as a human pathogen. It is mostly recovered from urinary and respiratory tract specimens as a commensal organism, but very seldom from bloodstream infections. It is rarely reported in the literature, probably due to misidentification of the organism or uncertainty of its pathogenicity.
Topics: Aged; Alcaligenaceae; Anti-Bacterial Agents; Aortic Valve Stenosis; Bacteremia; Drug Therapy, Combination; Gram-Negative Bacterial Infections; Humans; Male; Penicillanic Acid; Piperacillin; Risk Factors; Tazobactam; Treatment Outcome
PubMed: 27031899
DOI: No ID Found -
Advances in Microbial Physiology 2001The success of a bacterial pathogen may depend on its ability to sense and respond to different environments. This is particularly true of those pathogens whose survival... (Comparative Study)
Comparative Study Review
The success of a bacterial pathogen may depend on its ability to sense and respond to different environments. This is particularly true of those pathogens whose survival depends on adaptation to different niches both within and outside the host. Members of the genus Bordetella cause infections in humans, other animals and birds. Two closely related species, B. pertussis and B. bronchiseptica, cause respiratory disease and express a similar range of virulence factors during infection, but exhibit different host ranges and responses to environmental change. B. pertussis has no known reservoir other than humans and is assumed to be transmitted directly via aerosol droplets between hosts. B. bronchiseptica, on the other hand, has the potential to survive and grow in the natural environment. Comparison of the manner in which these two organisms respond to external signals has provided important insights into the co-ordinate regulation of gene expression as a response to a changing environment. During infection, both species produce a range of virulence factors whose expression is co-ordinated by two members of the two-component family of signal transduction proteins, the bvg (bordetella virulence gene) and ris (regulator of intracellular stress response) loci. When active, the bvg locus directs the activity of a number of virulence determinants in both species whose products, such as adhesins and toxins, establish colonization of the host by the bacteria, although each organism has evolved a slightly different strategy during pathogenesis. B. pertussis, the causative agent of whooping cough, promotes an acute disease and tends to be more virulent than B. bronchiseptica which generally causes chronic and persistent asymptomatic colonization of the respiratory tract. The recently identified ris locus appears to control the expression of factors important for intracellular survival of B. bronchiseptica, but a role for this regulatory locus in B. pertussis infection has not been established. Expression of the virulence determinants controlled by the bvg and ris loci is subject to modulation by different environmental signals, such as low temperature, which act through these two-component systems. Evidence indicates that, for B. bronchiseptica, bvg-controlled determinants expressed under modulating conditions, such as motility, facilitate adaptation and survival in environments outside the host. With B. pertussis, however, there is no apparent requirement for prolonged survival outside the host and this difference is reflected in the expression of different, as yet uncharacterized, determinants as a response to modulating signals. The nature of the gene products involved and their assumed role in the life cycle of B. pertussis remains to be determined. Thus, comparative analysis of these species provides an excellent model for understanding the genetic requirements for pathogenesis of respiratory infection and adaptation to changing environments, both within and outside the host.
Topics: Adaptation, Biological; Animals; Bordetella Infections; Bordetella bronchiseptica; Bordetella pertussis; Environment; Gene Expression Regulation, Bacterial; Humans; Signal Transduction; Virulence
PubMed: 11407112
DOI: 10.1016/s0065-2911(01)44013-6 -
International Journal of Systematic and... Feb 2022The genus encompasses five validly described species belonging to the betaproteobacterial class. Recognized for their potential biotechnological uses, they were first...
The genus encompasses five validly described species belonging to the betaproteobacterial class. Recognized for their potential biotechnological uses, they were first described as belonging to the genus . The phylogeny of the 16S rRNA gene of the original strains as well as newly described species led to a description of these strains within a new bacterial genus, . However, the phylogenetic position of this genus remains described as part of the family , even those some authors have placed it within the order . To unravel the precise position of the genus , a wide phylogenomic analysis was performed. The results of 16S rRNA gene phylogeny, as well as those obtained by the multilocus analysis of homologous proteins and overall genome relatedness indices, support the reclassification of in the lineage of the family , so the transfer of this genus is proposed.
Topics: Alcaligenaceae; Bacterial Typing Techniques; Base Composition; Comamonadaceae; DNA, Bacterial; Phylogeny; RNA, Ribosomal, 16S; Sequence Analysis, DNA
PubMed: 35138242
DOI: 10.1099/ijsem.0.005234