scholarly journals No endospore formation confirmed in members of the phylum Proteobacteria

2020 ◽  
Author(s):  
Polina Beskrovnaya ◽  
Doaa Fakih ◽  
Danielle L. Sexton ◽  
Shipei Xing ◽  
Mona Golmohammadzadeh ◽  
...  
Keyword(s):  
Environmental Conditions ◽  
Electron Tomography ◽  
Dipicolinic Acid ◽  
Gram Positive Bacteria ◽  
Cellular Debris ◽  
Conserved Genes ◽  
Genetic Features ◽  
Morphological Transformations ◽  
Outer Membrane Biogenesis ◽  
Analytical Approaches

AbstractEndospore formation is used by members of the phylum Firmicutes to withstand extreme environmental conditions. Several recent studies have documented endospore formation in species outside of Firmicutes, particularly in Rhodobacter johrii and Serratia marcescens, members of the phylum Proteobacteria. Here, we aimed to investigate endospore formation in these two species by using advanced imaging and analytical approaches. Examination of the phase-bright structures observed in R. johrii and S. marcescens using cryo-electron tomography failed to identify endospores or stages of endospore formation. We determined that the phase-bright objects in R. johrii cells were triacylglycerol storage granules and those in S. marcescens were aggregates of cellular debris. In addition, R. johrii and S. marcescens containing phase-bright objects do not possess phenotypic and genetic features of endospores, including enhanced resistance to heat, presence of dipicolinic acid, or the presence of many of the genes associated with endospore formation. Our results support the hypothesis that endospore formation is restricted to the phylum Firmicutes.ImportanceEndospore formation is a mechanism that allows bacteria to generate resilient dormant spores under harsh environmental conditions. Although this process has been traditionally restricted to the largely Gram-positive bacteria of the phylum Firmicutes, recent studies have also described endospores in some Proteobacteria. High complexity of endosporulation, reflected in extensive morphological transformations governed by hundreds of conserved genes, hinders its facile acquisition via horizontal gene transfer. Therefore, ability of distantly related bacteria to produce endospores would imply an ancient nature of this mechanism and potentially a pivotal role in species diversification and outer membrane biogenesis.

scholarly journals No endospore formation confirmed in members of the phylum Proteobacteria

2020 ◽  
pp. AEM.02312-20
Author(s):  
Polina Beskrovnaya ◽  
Doaa Fakih ◽  
Isabelle Morneau ◽  
Ameena Hashimi ◽  
Dainelys Guadarrama Bello ◽  
...  
Keyword(s):  
Serratia Marcescens ◽  
Environmental Conditions ◽  
Electron Tomography ◽  
Dipicolinic Acid ◽  
Life Forms ◽  
Cellular Debris ◽  
Genetic Features ◽  
Storage Granules ◽  
Analytical Approaches

Endospore formation is used by members of the phylum Firmicutes to withstand extreme environmental conditions. Several recent studies have proposed endospore formation in species outside of Firmicutes, particularly in Rhodobacter johrii and Serratia marcescens, members of the phylum Proteobacteria. Here, we aimed to investigate endospore formation in these two species by using advanced imaging and analytical approaches. Examination of the phase-bright structures observed in R. johrii and S. marcescens using cryo-electron tomography failed to identify endospores or stages of endospore formation. We determined that the phase-bright objects in R. johrii cells were triacylglycerol storage granules and those in S. marcescens were aggregates of cellular debris. In addition, R. johrii and S. marcescens containing phase-bright objects do not possess phenotypic and genetic features of endospores, including enhanced resistance to heat, presence of dipicolinic acid, or the presence of many of the genes associated with endospore formation. Our results support the hypothesis that endospore formation is restricted to the phylum Firmicutes.Importance: Bacterial endospore formation is an important process that allows the formation of dormant life forms called spores. As such, organisms able to sporulate can survive harsh environmental conditions for hundreds of years. Here, we follow up on previous claims that two members of Proteobacteria, Serratia marcescens and Rhodobacter johrii, are able to form spores. We conclude that those claims were incorrect and show that the putative spores in R. johrii and S. marcescens are storage granules and cellular debris, respectively. This study concludes that endospore formation is still unique to the phylum Firmicutes.

scholarly journals Decoding the Genomic Variability among Members of the Bifidobacterium dentium Species

2020 ◽  
Vol 8 (11) ◽  
pp. 1720
Author(s):  
Gabriele Andrea Lugli ◽  
Chiara Tarracchini ◽  
Giulia Alessandri ◽  
Christian Milani ◽  
Leonardo Mancabelli ◽  
...  
Keyword(s):  
Defense Mechanisms ◽  
Ursus Arctos ◽  
Primate Species ◽  
Comparative Genomic ◽  
Glycosyl Hydrolases ◽  
Genomic Variability ◽  
Fecal Samples ◽  
Genomic Analyses ◽  
Conserved Genes ◽  
Genetic Features

Members of the Bifidobacterium dentium species are usually identified in the oral cavity of humans and associated with the development of plaque and dental caries. Nevertheless, they have also been detected from fecal samples, highlighting a widespread distribution among mammals. To explore the genetic variability of this species, we isolated and sequenced the genomes of 18 different B. dentium strains collected from fecal samples of several primate species and an Ursus arctos. Thus, we investigated the genomic variability and metabolic abilities of the new B. dentium isolates together with 20 public genome sequences. Comparative genomic analyses provided insights into the vast metabolic repertoire of the species, highlighting 19 glycosyl hydrolases families shared between each analyzed strain. Phylogenetic analysis of the B. dentium taxon, involving 1140 conserved genes, revealed a very close phylogenetic relatedness among members of this species. Furthermore, low genomic variability between strains was also confirmed by an average nucleotide identity analysis showing values higher than 98.2%. Investigating the genetic features of each strain, few putative functional mobile elements were identified. Besides, a consistent occurrence of defense mechanisms such as CRISPR–Cas and restriction–modification systems may be responsible for the high genome synteny identified among members of this taxon.

scholarly journals Elucidating the genome of Emydura subglobosa through manual annotation and computational biology tools

2021 ◽  
Author(s):  
Megan R Yu
Keyword(s):  
High Frequency ◽  
Manual Annotation ◽  
Genomic Technologies ◽  
Consensus Models ◽  
Functional Localization ◽  
Genes Encoding ◽  
Conserved Genes ◽  
Genetic Features ◽  
Fatty Acid Catabolism ◽  
Olfactory Gene

Rapid advancements in automated genomic technologies have uncovered many unique findings about the turtle genome and its associated features including olfactory gene expansions and duplications of toll-like receptors. However, automated technologies often result in a high frequency of errors through the process of assembly and annotation and highlight the need for manual annotation. In this study, we have manually annotated four genes of the red-bellied short-neck turtle (Emydura subglobosa), an understudied outgroup of turtles representing a diverse lineage. We improved upon initial ab initio gene predictions through homology-based evidence and generated refined consensus models. Through functional, localization, and structural analyses of the predicted proteins, we have discovered conserved genes encoding proteins that play a role in C21-steroid hormone biosynthetic processes, Vitamin A uptake, collagen/elastin integrity, tumor suppression, and fatty acid catabolism. Overall, these findings further our knowledge about the genetic features underlying turtle physiology, morphology, and longevity, which could have important implications for the treatment of human diseases and evolutionary studies.

scholarly journals Conceptual Design and Multi-Disciplinary Computational Investigations of Multirotor Unmanned Aerial Vehicle for Environmental Applications

2021 ◽  
Vol 11 (18) ◽  
pp. 8364
Author(s):  
Vijayanandh Raja ◽  
Senthil Kumar Solaiappan ◽  
Parvathy Rajendran ◽  
Senthil Kumar Madasamy ◽  
Sunghun Jung
Keyword(s):  
Conceptual Design ◽  
Unmanned Aerial Vehicle ◽  
Environmental Conditions ◽  
Dynamic Pressure ◽  
Suitable Material ◽  
Flow Mixing ◽  
Fluid Properties ◽  
Aerial Vehicle ◽  
Microphysical Processes ◽  
Analytical Approaches

This study focuses on establishing a conceptual design for a multirotor unmanned aerial vehicle (UAV). The objectives of this octocopter are to reduce the number of flight cancelations and car accidents owing to low-visibility issues and to improve abnormal environmental conditions due to the presence of smoke. The proposed octocopter contains a convergent–divergent [CD] duct-based storage tank, which provides a platform to store saltwater and allows it to fly in foggy zones. Fine saltwater is sprayed from the octocopter and dispersed into the low clouds, thereby altering the vapor’s microphysical processes to break it up and improve visibility. The nature of the seawater and its enhanced fluid properties, due to the involvement of octocopter, creates the fluid flow mixing between atmospheric fluids and spraying particles, which increases the settling of foggy and smokey content groundward. For deployment, the conceptual design of the octocopter was initially constructed through analytical approaches. Additionally, three unique historical relationships were created. The standard engineering approaches involved in this work were stability analysis through MATLAB and fluid-property analysis through computational fluid dynamics (CFD) cum multiple reference frame (MRF) tools. The systematic model of this octocopter was developed by CATIA, and thereafter CFD and fluid–structure-interaction (FSI) analyses were computed, in ANSYS Workbench, on the octocopter for various environmental conditions. The aerodynamic forces on the drone, the enhancement of dynamic pressure by the presence of high amounts of rotors and nozzle sprayer, suitable material to resist aerodynamic loadings, and tests on the efficiency of the controller and its electronic components were investigated in detail. Finally, the proposed octocopter-based dynamic system was conceptually constructed.

scholarly journals Nocturnal Production of Endospores in Natural Populations of Epulopiscium-Like Surgeonfish Symbionts

2005 ◽  
Vol 187 (21) ◽  
pp. 7460-7470 ◽  
Author(s):  
Joseph F. Flint ◽  
Dan Drzymalski ◽  
W. Linn Montgomery ◽  
Gordon Southam ◽  
Esther R. Angert
Keyword(s):  
Intestinal Tract ◽  
Dipicolinic Acid ◽  
Phylogenetic Analyses ◽  
Natural Populations ◽  
Rrna Gene ◽  
Gram Positive Bacteria ◽  
Close Relationship ◽  
Close Relatives ◽  
In Situ Hybridizations

ABSTRACT Prior studies have described a morphologically diverse group of intestinal microorganisms associated with surgeonfish. Despite their diversity of form, 16S rRNA gene surveys and fluorescent in situ hybridizations indicate that these bacteria are low-G+C gram-positive bacteria related to Epulopiscium spp. Many of these bacteria exhibit an unusual mode of reproduction, developing multiple offspring intracellularly. Previous reports have suggested that some Epulopiscium-like symbionts produce dormant or phase-bright intracellular offspring. Close relatives of Epulopiscium, such as Metabacterium polyspora and Clostridium lentocellum, are endospore-forming bacteria, which raises the possibility that the phase-bright offspring are endospores. Structural evidence and the presence of dipicolinic acid demonstrate that phase-bright offspring of Epulopiscium-like bacteria are true endospores. In addition, endospores are formed as part of the normal daily life cycle of these bacteria. In the populations studied, mature endospores were seen only at night and the majority of cells in a given population produced one or two endospores per mother cell. Phylogenetic analyses confirmed the close relationship between the endospore-forming surgeonfish symbionts characterized here and previously described Epulopiscium spp. The broad distribution of endospore formation among the Epulopiscium phylogenetic group raises the possibility that sporulation is a characteristic of the group. We speculate that spore formation in Epulopiscium-like symbionts may be important for dispersal and may also enhance survival in the changing conditions of the fish intestinal tract.

scholarly journals WhiA, a Protein of Unknown Function Conserved among Gram-Positive Bacteria, Is Essential for Sporulation inStreptomyces coelicolor A3(2)

2000 ◽  
Vol 182 (19) ◽  
pp. 5470-5478 ◽  
Author(s):  
J. A. Aínsa ◽  
N. J. Ryding ◽  
N. Hartley ◽  
K. C. Findlay ◽  
C. J. Bruton ◽  
...  
Keyword(s):  
Unknown Function ◽  
Streptomyces Coelicolor ◽  
Wild Type Allele ◽  
Wild Type ◽  
Phenotypic Analysis ◽  
Gram Positive ◽  
Gene Encoding ◽  
Gram Positive Bacteria ◽  
Aerial Hyphae ◽  
Conserved Genes

ABSTRACT The whiA sporulation gene of Streptomyces coelicolor A3(2), which plays a key role in switching aerial hyphae away from continued extension growth and toward sporulation septation, was cloned by complementation of whiA mutants. DNA sequencing of the wild-type allele and five whiAmutations verified that whiA is a gene encoding a protein with homologues in all gram-positive bacteria whose genome sequence is known, whether of high or low G+C content. No function has been attributed to any of these WhiA-like proteins. In most cases, as inS. coelicolor, the whiA-like gene is downstream of other conserved genes in an operon-like cluster. Phenotypic analysis of a constructed disruption mutant confirmed that whiA is essential for sporulation. whiA is transcribed from at least two promoters, the most downstream of which is located within the preceding gene and is strongly up-regulated when colonies are undergoing sporulation. The up-regulation depends on a functionalwhiA gene, suggesting positive autoregulation, although it is not known whether this is direct or indirect. Unlike the promoters of some other sporulation-regulatory genes, the whiApromoter does not depend on the sporulation-specific ς factor encoded by whiG.

scholarly journals Genetic features of circular bacteriocins produced by Gram-positive bacteria

2008 ◽  
Vol 32 (1) ◽  
pp. 2-22 ◽  
Author(s):  
Mercedes Maqueda ◽  
Marina Sánchez-Hidalgo ◽  
Matilde Fernández ◽  
Manuel Montalbán-López ◽  
Eva Valdivia ◽  
...  
Keyword(s):  
Gram Positive ◽  
Gram Positive Bacteria ◽  
Genetic Features

scholarly journals Characteristics of Spoilage-Associated Secondary Cucumber Fermentation

2011 ◽  
Vol 78 (4) ◽  
pp. 1273-1284 ◽  
Author(s):  
Wendy Franco ◽  
Ilenys M. Pérez-Díaz ◽  
Suzanne D. Johanningsmeier ◽  
Roger F. McFeeters
Keyword(s):  
Lactic Acid ◽  
Environmental Conditions ◽  
Morphological Characteristics ◽  
Allyl Isothiocyanate ◽  
Content Type ◽  
Gram Positive Bacteria ◽  
Causative Agents ◽  
Pichia Manshurica ◽  
Small Decline ◽  
Metabolic Activities

ABSTRACTSecondary fermentations during the bulk storage of fermented cucumbers can result in spoilage that causes a total loss of the fermented product, at an estimated cost of $6,000 to $15,000 per affected tank. Previous research has suggested that such fermentations are the result of microbiological utilization of lactic acid and the formation of acetic, butyric, and propionic acids. The objectives of this study were to characterize the chemical and environmental conditions associated with secondary cucumber fermentations and to isolate and characterize potential causative microorganisms. Both commercial spoilage samples and laboratory-reproduced secondary fermentations were evaluated. Potential causative agents were isolated based on morphological characteristics. Two yeasts,Pichia manshuricaandIssatchenkia occidentalis, were identified and detected most commonly concomitantly with lactic acid utilization. In the presence of oxygen, yeast metabolic activities lead to lactic acid degradation, a small decline in the redox potential (Eh, Ag/AgCl, 3 M KCl) of the fermentation brines, and an increase in pH to levels at which bacteria other than the lactic acid bacteria responsible for the primary fermentation can grow and produce acetic, butyric, and propionic acids. Inhibition of these yeasts by allyl isothiocyanate (AITC) resulted in stabilization of the fermented medium, while the absence of the preservative resulted in the disappearance of lactic and acetic acids in a model system. Additionally, three Gram-positive bacteria,Lactobacillus buchneri, aClostridiumsp., andPediococcus ethanolidurans, were identified as potentially relevant to different stages of the secondary fermentation. The unique opportunity to study commercial spoilage samples generated a better understanding of the microbiota and environmental conditions associated with secondary cucumber fermentations.

Effects of Stitching Parameters on Tensile Strength of FRPs under Hygrothermal Conditions

2012 ◽  
Vol 570 ◽  
pp. 63-77
Author(s):  
Xiao Quan Cheng ◽  
Yasir Baig ◽  
Zheng Neng Li
Keyword(s):  
Tensile Strength ◽  
Environmental Conditions ◽  
Failure Strength ◽  
Test Results ◽  
Validity Of Results ◽  
Fem Model ◽  
Strength Performance ◽  
Hygrothermal Environment ◽  
Analytical Approaches ◽  
Environment Condition

An investigation based on experimental and analytical approaches was conducted to evaluate the behavior of the stitched laminates under hygrothermal conditions. Tensile strength of laminates under different environmental conditions was predicted using FEM model. Effects of stitching parameters upon strength performance of laminates were studied using FEM model and validity of results was checked by comparing with the experimental results. Test results have shown that hygrothermal environment condition has no significant effect on the tensile strength of unstitched laminates, but improved the strength of stitched laminates significantly. Stitching decreased the tensile strength of laminates under 20°C dry environment; however, it improved the tensile strength under 20°C wet environment. It was also found from analytical results that, the failure strength of stitched laminates is higher for smaller thread radius (R<0.25) and relatively greater (5~6mm) stitching distance (5~6mm).

scholarly journals How to accurately assess surfactant biodegradation-impact of sorption on the validity of results

2019 ◽  
Vol 104 (1) ◽  
pp. 1-12 ◽  
Author(s):  
Dorota Cierniak ◽  
Marta Woźniak-Karczewska ◽  
Anna Parus ◽  
Bogdan Wyrwas ◽  
Andreas P. Loibner ◽  
...  
Keyword(s):  
Activated Sludge ◽  
Systematic Approach ◽  
Analytical Signal ◽  
Modern World ◽  
Validity Of Results ◽  
Gram Positive Bacteria ◽  
Biotechnological Processes ◽  
Analytical Approaches ◽  
Surfactant Sorption ◽  
Main Factor

AbstractSurfactants not only are widely used in biotechnological processes but also constitute significant contaminants of the modern world. Among many reports, there is a shortage of works which summarize the issue of surfactant sorption to biomass in a way that would elucidate the biological factors for analysts and analytical factors for microbiologists. The main factor, which is not as obvious as one would expect, is associated with the susceptibility of analytical approaches to errors resulting from incorrect handling of biomass. In case of several publications reviewed in the framework of this study, it was not possible to establish whether the decrease of the analytical signal observed by the authors actually resulted from biodegradation of the surfactant. This review emphasizes the necessity to consider the possibility of surfactant sorption to microbial cells, which may result in significant detection errors as well as conceptual inconsistency. In addition, a reference study regarding representative surfactants (cationic, anionic and non-ionic) as well as yeast, Gram-negative, Gram-positive bacteria, and activated sludge was provided to highlight the possible errors which may arise from disregarding sorption processes when determining degradation of surfactants. This particularly applies to systems which include ionic surfactants and activated sludge as sorption may account for 90% of the observed depletion of the surfactant. Therefore, a systematic approach was proposed in order to improve the credibility of the obtained results. Finally, the need to employ additional procedures was highlighted which may be required in order to verify that the decrease of surfactant concentration results from biodegradation processes.

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