scholarly journals Delineation of Steroid-Degrading Microorganisms through Comparative Genomic Analysis

mBio ◽  
2016 ◽  
Vol 7 (2) ◽  
Author(s):  
Lee H. Bergstrand ◽  
Erick Cardenas ◽  
Johannes Holert ◽  
Jonathan D. Van Hamme ◽  
William W. Mohn
Keyword(s):  
Pathogenic Bacteria ◽  
Gene Clusters ◽  
Degradation Pathway ◽  
Steroid Metabolism ◽  
Individual Species ◽  
Ecological Niches ◽  
Comparative Genomic ◽  
Bacterial Strains ◽  
Pathway Gene ◽  
Steroid Catabolism

ABSTRACT Steroids are ubiquitous in natural environments and are a significant growth substrate for microorganisms. Microbial steroid metabolism is also important for some pathogens and for biotechnical applications. This study delineated the distribution of aerobic steroid catabolism pathways among over 8,000 microorganisms whose genomes are available in the NCBI RefSeq database. Combined analysis of bacterial, archaeal, and fungal genomes with both hidden Markov models and reciprocal BLAST identified 265 putative steroid degraders within only Actinobacteria and Proteobacteria , which mainly originated from soil, eukaryotic host, and aquatic environments. These bacteria include members of 17 genera not previously known to contain steroid degraders. A pathway for cholesterol degradation was conserved in many actinobacterial genera, particularly in members of the Corynebacterineae , and a pathway for cholate degradation was conserved in members of the genus Rhodococcus . A pathway for testosterone and, sometimes, cholate degradation had a patchy distribution among Proteobacteria . The steroid degradation genes tended to occur within large gene clusters. Growth experiments confirmed bioinformatic predictions of steroid metabolism capacity in nine bacterial strains. The results indicate there was a single ancestral 9,10-seco-steroid degradation pathway. Gene duplication, likely in a progenitor of Rhodococcus , later gave rise to a cholate degradation pathway. Proteobacteria and additional Actinobacteria subsequently obtained a cholate degradation pathway via horizontal gene transfer, in some cases facilitated by plasmids. Catabolism of steroids appears to be an important component of the ecological niches of broad groups of Actinobacteria and individual species of Proteobacteria . IMPORTANCE Steroids are ubiquitous growth substrates for environmental and pathogenic bacteria, and bacterial steroid metabolism has important pharmaceutical and health applications. To date, the genetics and biochemistry of microbial steroid degradation have mainly been studied in a few model bacteria, and the diversity of this metabolism remains largely unexplored. Here, we provide a bioinformatically derived perspective of the taxonomic distribution of aerobic microbial steroid catabolism pathways. We identified several novel steroid-degrading bacterial groups, including ones from marine environments. In several cases, we confirmed bioinformatic predictions of metabolism in cultures. We found that cholesterol and cholate catabolism pathways are highly conserved among certain actinobacterial taxa. We found evidence for horizontal transfer of a pathway to several proteobacterial genera, conferring testosterone and, sometimes, cholate catabolism. The results of this study greatly expand our ecological and evolutionary understanding of microbial steroid metabolism and provide a basis for better exploiting this metabolism for biotechnology.

scholarly journals Targeted Genome Mining Reveals the Psychrophilic Clostridium estertheticum Complex as a Potential Source for Novel Bacteriocins, Including Cesin A and Estercticin A

2022 ◽  
Vol 12 ◽  
Author(s):  
Joseph Wambui ◽  
Marc J. A. Stevens ◽  
Simon Sieber ◽  
Nicole Cernela ◽  
Vincent Perreten ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Proteolytic Enzymes ◽  
Genome Mining ◽  
Gene Clusters ◽  
Public Health Issue ◽  
Ecological Niches ◽  
Primary Screening ◽  
Secondary Screening ◽  
Natural Variant ◽  
Screening Assays

Antimicrobial resistance in pathogenic bacteria is considered a major public health issue necessitating the discovery of alternative antimicrobial compounds. In this regard, targeted genome mining in bacteria occupying under-explored ecological niches has the potential to reveal such compounds, including bacteriocins. In this study, we determined the bacteriocin biosynthetic potential of the psychrophilic Clostridium estertheticum complex (CEC) through a combination of genome mining and phenotypic screening assays. The genome mining was performed in 40 CEC genomes using antiSMASH. The production of bacteriocin-like compounds was phenotypically validated through agar well (primary screening) and disk diffusion (secondary screening) assays using cell free supernatants (CFS) and partially purified extracts, respectively. Stability of four selected CFS against proteolytic enzymes, temperature and pH was determined while one CFS was analyzed by HRMS and MS/MS to identify potential bacteriocins. Twenty novel bacteriocin biosynthetic gene clusters (BBGC), which were classified into eight (six lantibiotics and two sactipeptides) distinct groups, were discovered in 18 genomes belonging to C. estertheticum (n = 12), C. tagluense (n = 3) and genomospecies2 (n = 3). Primary screening linked six BBGC with narrow antimicrobial activity against closely related clostridia species. All four preselected CFS retained activity after exposure to different proteolytic, temperature and pH conditions. Secondary screening linked BBGC1 and BBGC7 encoding a lantibiotic and sactipeptide, respectively, with activity against Bacillus cereus while lantibiotic-encoding BBGC2 and BBGC3 were linked with activity against B. cereus, Staphylococcus aureus (methicillin-resistant), Escherichia coli and Pseudomonas aeruginosa. MS/MS analysis revealed that C. estertheticum CF004 produces cesin A, a short natural variant of nisin, and HRMS indicated the production of a novel sactipeptide named estercticin A. Therefore, we have shown the CEC, in particular C. estertheticum, is a source of novel and stable bacteriocins that have activities against clinically relevant pathogens.

scholarly journals Comparative Genomic Analyses of Seventeen Streptococcus pneumoniae Strains: Insights into the Pneumococcal Supragenome

2007 ◽  
Vol 189 (22) ◽  
pp. 8186-8195 ◽  
Author(s):  
N. Luisa Hiller ◽  
Benjamin Janto ◽  
Justin S. Hogg ◽  
Robert Boissy ◽  
Susan Yu ◽  
...  
Keyword(s):  
Pathogenic Bacteria ◽  
Genetic Recombination ◽  
Orthologous Gene ◽  
Gene Clusters ◽  
Comparative Genomic ◽  
Host Interaction ◽  
Genomic Analyses ◽  
Strain Pair ◽  
Interaction Strategy ◽  
Genic Diversity

ABSTRACT The distributed-genome hypothesis (DGH) states that pathogenic bacteria possess a supragenome that is much larger than the genome of any single bacterium and that these pathogens utilize genetic recombination and a large, noncore set of genes as a means of diversity generation. We sequenced the genomes of eight nasopharyngeal strains of Streptococcus pneumoniae isolated from pediatric patients with upper respiratory symptoms and performed quantitative genomic analyses among these and nine publicly available pneumococcal strains. Coding sequences from all strains were grouped into 3,170 orthologous gene clusters, of which 1,454 (46%) were conserved among all 17 strains. The majority of the gene clusters, 1,716 (54%), were not found in all strains. Genic differences per strain pair ranged from 35 to 629 orthologous clusters, with each strain's genome containing between 21 and 32% noncore genes. The distribution of the orthologous clusters per genome for the 17 strains was entered into the finite-supragenome model, which predicted that (i) the S. pneumoniae supragenome contains more than 5,000 orthologous clusters and (ii) 99% of the orthologous clusters (∼3,000) that are represented in the S. pneumoniae population at frequencies of ≥0.1 can be identified if 33 representative genomes are sequenced. These extensive genic diversity data support the DGH and provide a basis for understanding the great differences in clinical phenotype associated with various pneumococcal strains. When these findings are taken together with previous studies that demonstrated the presence of a supragenome for Streptococcus agalactiae and Haemophilus influenzae, it appears that the possession of a distributed genome is a common host interaction strategy.

scholarly journals Annotated Draft Genomes of Two Caddisfly Species Plectrocnemia conspersa CURTIS and Hydropsyche tenuis NAVAS (Insecta: Trichoptera)

2019 ◽  
Vol 11 (12) ◽  
pp. 3445-3451 ◽  
Author(s):  
Jacqueline Heckenhauer ◽  
Paul B Frandsen ◽  
Deepak K Gupta ◽  
Juraj Paule ◽  
Stefan Prost ◽  
...  
Keyword(s):  
De Novo ◽  
Low Cost ◽  
Gene Clusters ◽  
Genomic Region ◽  
Ecological Niches ◽  
Comparative Genomic ◽  
Insect Order ◽  
Wide Range ◽  
Sequencing Strategy ◽  
Genomic Studies

Abstract Members of the speciose insect order Trichoptera (caddisflies) provide important ecosystem services, for example, nutrient cycling through breaking down of organic matter. They are also of industrial interest due to their larval silk secretions. These form the basis for their diverse case-making behavior that allows them to exploit a wide range of ecological niches. Only five genomes of this order have been published thus far, with variable qualities regarding contiguity and completeness. A low-cost sequencing strategy, that is, using a single Oxford Nanopore flow cell per individual along with Illumina sequence reads was successfully used to generate high-quality genomes of two Trichoptera species, Plectrocnemia conspersa and Hydropsyche tenuis. Of the de novo assembly methods compared, assembly of low coverage Nanopore reads (∼18×) and subsequent polishing with long reads followed by Illumina short reads (∼80–170× coverage) yielded the highest genome quality both in terms of contiguity and BUSCO completeness. The presented genomes are the shortest to date and extend our knowledge of genome size across caddisfly families. The genomic region that encodes for light (L)-chain fibroin, a protein component of larval caddisfly silk was identified and compared with existing L-fibroin gene clusters. The new genomic resources presented in this paper are among the highest quality Trichoptera genomes and will increase the knowledge of this important insect order by serving as the basis for phylogenomic and comparative genomic studies.

scholarly journals Comparative genomic analysis of gene clusters of Pseudomonas aeruginosa that define specific biofilm formation in deciphering target regions for novel treatment options

2020 ◽  
Author(s):  
Michael Ambutsi ◽  
Oleg Reva ◽  
Patrick Okoth
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Biofilm Formation ◽  
Phylogenetic Analyses ◽  
Treatment Options ◽  
Gene Clusters ◽  
Opportunistic Pathogen ◽  
Natural Resistance ◽  
Future Research ◽  
Ecological Niches ◽  
Comparative Genomic

Abstract Background Pseudomonas aeruginosa is an opportunistic pathogen associated with numerous nosocomial infections that are difficult to treat as a result of natural resistance to various antibiotics, particularly because of biofilm formation. The purpose of this study was to determine the distribution of biofilm formation genes in sequences of this opportunistic pathogen and their association with different ecological niches. In total, 13 genes responsible for biofilm formation by P. aeruginosa were identified and used in the study. They were clustered into seven categories based on the role they play in the biofilm formation process. The study also analyzed 185 complete genome sequences of P. aeruginosa strains retrieved from the NCBI and IPCD databases. These were classified into 14 categories based on the ecological niches they occupy. Results Phylogenetic analyses of the biofilm formation genes indicated a strong co-evolution of a majority of these genes, n=10 . Exceptions were the genes fliC, algD, and algU which may have been exchanged by horizontal gene transfer or evolved faster than the other genes of this functional group as they are more important in terms of a proper response of the biofilm formation to specific environmental stimuli in different habitats. The BLAST Ring Image Generator (BRIG) analysis was used to visualize the distribution of biofilm formation genes between different strains of P. aeruginosa . Conclusions fliC, algD, and algU genes were identified as potential targets for antibiofilm therapies. These findings could inform the development of antibiofilm therapies that target processes mediated by these genes. Also, this study provides useful information that can guide the direction of future research.

scholarly journals Genome Sequences of 72 Bacterial Strains Isolated from Ectocarpus subulatus: A Resource for Algal Microbiology

2019 ◽  
Vol 12 (1) ◽  
pp. 3647-3655 ◽  
Author(s):  
Elham Karimi ◽  
Enora Geslain ◽  
Hetty KleinJan ◽  
Gwenn Tanguy ◽  
Erwan Legeay ◽  
...  
Keyword(s):  
Draft Genome ◽  
Gene Clusters ◽  
Homoserine Lactone ◽  
Point Of View ◽  
Laboratory Model ◽  
Comparative Genomic ◽  
Bacterial Strains ◽  
Genome Sequences ◽  
Associated Bacteria ◽  
Algal Host

Abstract Brown algae are important primary producers and ecosystem engineers in the ocean, and Ectocarpus has been established as a laboratory model for this lineage. Like most multicellular organisms, Ectocarpus is associated with a community of microorganisms, a partnership frequently referred to as holobiont due to the tight interconnections between the components. Although genomic resources for the algal host are well established, its associated microbiome is poorly characterized from a genomic point of view, limiting the possibilities of using these types of data to study host–microbe interactions. To address this gap in knowledge, we present the annotated draft genome sequences of seventy-two cultivable Ectocarpus-associated bacteria. A screening of gene clusters related to the production of secondary metabolites revealed terpene, bacteriocin, NRPS, PKS-t3, siderophore, PKS-t1, and homoserine lactone clusters to be abundant among the sequenced genomes. These compounds may be used by the bacteria to communicate with the host and other microbes. Moreover, detoxification and provision of vitamin B pathways have been observed in most sequenced genomes, highlighting potential contributions of the bacterial metabolism toward host fitness and survival. The genomes sequenced in this study form a valuable resource for comparative genomic analyses and evolutionary surveys of alga-associated bacteria. They help establish Ectocarpus as a model for brown algal holobionts and will enable the research community to produce testable hypotheses about the molecular interactions within this complex system.

scholarly journals Comparative genomic analysis of Flavobacteriaceae: insights into carbohydrate metabolism, gliding motility and secondary metabolite biosynthesis.

2020 ◽  
Author(s):  
Asimenia Gavriilidou ◽  
Johanna Gutleben ◽  
Dennis Versluis ◽  
Francesca Forgiarini ◽  
Mark WJ van Passel ◽  
...  
Keyword(s):  
Antimicrobial Activity ◽  
Carbohydrate Metabolism ◽  
Secondary Metabolite ◽  
Gene Clusters ◽  
Gliding Motility ◽  
Ecological Niches ◽  
Comparative Genomic ◽  
Rrna Gene ◽  
Metabolic Potential ◽  
Secondary Metabolite Biosynthesis

Abstract BackgroundMembers of the bacterial family Flavobacteriaceae are widely distributed in the marine environment and often found associated with algae, fish, detritus or marine invertebrates. Yet, little is known about the characteristics that drive their ubiquity in diverse ecological niches. Here, we provide an overview of functional traits common to taxonomically diverse members of the family Flavobacteriaceae from different environmental sources, with a focus on the Marine clade. We include seven newly sequenced marine sponge-derived strains that were also tested for gliding motility and antimicrobial activity. ResultsComparative genomics revealed that genome similarities appeared to be correlated to 16S rRNA gene phylogeny, while differences were mostly associated with nutrient acquisition, such as carbohydrate metabolism and gliding motility. The high frequency and diversity of genes encoding polymer-degrading enzymes support the capacity of marine Flavobacteriaceae to utilize diverse carbon sources. Homologs of gliding proteins were widespread among all studied Flavobacteriaceae in contrast to members of other phyla, highlighting the particular presence of this feature within the Bacteroidetes. Notably, not all gliding bacteria formed spreading colonies. Genome mining uncovered a diverse secondary metabolite biosynthesis arsenal of Flavobacteriaceae with high prevalence of gene clusters encoding pathways for the production of antimicrobial, antioxidant and cytotoxic compounds. Antimicrobial activity tests showed, however, that the phenotype differed from the genome-derived predictions for the seven tested strains.ConclusionsOur study elucidates the functional repertoire of marine Flavobacteriaceae and highlights the need to combine genomic and experimental data while using the appropriate stimuli to unlock their uncharted metabolic potential.

Preliminary in Vitro Investigations on The Inhibitory Activity of The Original Dietary Supplement Oxidal® on Pathogenic Bacterial Strains

2020 ◽  
Vol 11 ◽  
pp. 37-43
Author(s):  
Prof. Teodora P. Popova ◽  
Toshka Petrova ◽  
Ignat Ignatov ◽  
Stoil Karadzhov
Keyword(s):  
Dietary Supplement ◽  
Broad Spectrum ◽  
Pathogenic Bacteria ◽  
Antimicrobial Agents ◽  
Clinical Effectiveness ◽  
Inhibitory Effect ◽  
Diffusion Method ◽  
Bacterial Strains ◽  
Microbial Strains

The antimicrobial action of the dietary supplement Oxidal® was tested using the classic Bauer and Kirby agar-gel diffusion method. Clinical and reference strains of Staphylococcus aureus and Escherichia coli were used in the studies. The tested dietary supplement showed a well-pronounced inhibitory effect against the microbial strains commensurable with that of the broad-spectrum chemotherapeutic agent Enrofloxacin and showed even higher activity than the broad spectrum antibiotic Thiamphenicol. The proven inhibitory effect of the tested dietary supplement against the examined pathogenic bacteria is in accordance with the established clinical effectiveness standards for antimicrobial agents.

Corticosteroid Catabolism by Klebsiella pneumoniae as a Possible Mechanism for Increased Pneumonia Risk

2019 ◽  
Vol 20 (4) ◽  
pp. 309-316 ◽  
Author(s):  
Pritam Chattopadhyay ◽  
Goutam Banerjee
Keyword(s):  
Amino Acid ◽  
Klebsiella Pneumoniae ◽  
Kegg Pathway ◽  
Degradation Pathway ◽  
Amino Acid Sequences ◽  
Biological Mechanism ◽  
Clinical Strains ◽  
Catabolism Pathway ◽  
Steroid Catabolism ◽  
Nutrition Source

Background: Several strains of Klebsiella pneumoniae are responsible for causing pneumonia in lung and thereby causing death in immune-suppressed patients. In recent year, few investigations have reported the enhancement of K. pneumoniae population in patients using corticosteroid containing inhaler. Objectives: The biological mechanism(s) behind this increased incidence has not been elucidated. Therefore, the objective of this investigating was to explore the relation between Klebsiella pneumoniae and increment in carbapenamase producing Enterobacteriaceae score (ICS). Methods: The available genomes of K. pneumoniae and the amino acid sequences of steroid catabolism pathway enzymes were taken from NCBI database and KEGG pathway tagged with UniPort database, respectively. We have used different BLAST algorithms (tBLASTn, BLASTp, psiBLAST, and delBLAST) to identify enzymes (by their amino acid sequence) involved in steroid catabolism. Results: A total of 13 enzymes (taken from different bacterial candidates) responsible for corticosteroid degradation have been identified in the genome of K. pneumoniae. Finally, 8 enzymes (K. pneumoniae specific) were detected in four clinical strains of K. pneumoniae. This investigation intimates that this ability to catabolize corticosteroids could potentially be one mechanism behind the increased pneumonia incidence. Conclusion: The presence of corticosteroid catabolism enzymes in K. pneumoniae enhances the ability to utilize corticosteroid for their own nutrition source. This is the first report to demonstrate the corticosteroid degradation pathway in clinical strains of K. pneumoniae.

scholarly journals Further Studies on the 3-Ketosteroid 9α-Hydroxylase of Rhodococcus ruber Chol-4, a Rieske Oxygenase of the Steroid Degradation Pathway

2021 ◽  
Vol 9 (6) ◽  
pp. 1171
Author(s):  
Sara Baldanta ◽  
Juana María Navarro Llorens ◽  
Govinda Guevara
Keyword(s):  
Cholesterol Metabolism ◽  
Genetic Regulation ◽  
Degradation Pathway ◽  
Rhodococcus Ruber ◽  
Promoter Regions ◽  
Steroid Nucleus ◽  
Steroid Substrate ◽  
Fine Regulation ◽  
Rieske Oxygenase ◽  
Steroid Catabolism

The biochemistry and genetics of the bacterial steroid catabolism have been extensively studied during the last years and their findings have been essential to the development of biotechnological applications. For instance, metabolic engineering of the steroid-eater strains has allowed to obtain intermediaries of industrial value. However, there are still some drawbacks that must be overcome, such as the redundancy of the steroid catabolism genes in the genome and a better knowledge of its genetic regulation. KshABs and KstDs are key enzymes involved in the aerobic breakage of the steroid nucleus. Rhodococcus ruber Chol-4 contains three kshAs genes, a single kshB gene and three kstDs genes within its genome. In the present work, the growth of R. ruber ΔkshA strains was evaluated on different steroids substrates; the promoter regions of these genes were analyzed; and their expression was followed by qRT-PCR in both wild type and ksh mutants. Additionally, the transcription level of the kstDs genes was studied in the ksh mutants. The results show that KshA2B and KshA1B are involved in AD metabolism, while KshA3B and KshA1B contribute to the cholesterol metabolism in R. ruber. In the kshA single mutants, expression of the remaining kshA and kstD genes is re-organized to survive on the steroid substrate. These data give insight into the fine regulation of steroid genes when several isoforms are present.

scholarly journals Categorization of Orthologous Gene Clusters in 92 Ascomycota Genomes Reveals Functions Important for Phytopathogenicity

2021 ◽  
Vol 7 (5) ◽  
pp. 337
Author(s):  
Daniel Peterson ◽  
Tang Li ◽  
Ana M. Calvo ◽  
Yanbin Yin
Keyword(s):  
Comparative Genomics ◽  
Orthologous Gene ◽  
Gene Clusters ◽  
Phytopathogenic Fungi ◽  
Secreted Proteins ◽  
Economic Losses ◽  
Comparative Genomic ◽  
Signal Peptides ◽  
Comparative Genomics Analysis

Phytopathogenic Ascomycota are responsible for substantial economic losses each year, destroying valuable crops. The present study aims to provide new insights into phytopathogenicity in Ascomycota from a comparative genomic perspective. This has been achieved by categorizing orthologous gene groups (orthogroups) from 68 phytopathogenic and 24 non-phytopathogenic Ascomycota genomes into three classes: Core, (pathogen or non-pathogen) group-specific, and genome-specific accessory orthogroups. We found that (i) ~20% orthogroups are group-specific and accessory in the 92 Ascomycota genomes, (ii) phytopathogenicity is not phylogenetically determined, (iii) group-specific orthogroups have more enriched functional terms than accessory orthogroups and this trend is particularly evident in phytopathogenic fungi, (iv) secreted proteins with signal peptides and horizontal gene transfers (HGTs) are the two functional terms that show the highest occurrence and significance in group-specific orthogroups, (v) a number of other functional terms are also identified to have higher significance and occurrence in group-specific orthogroups. Overall, our comparative genomics analysis determined positive enrichment existing between orthogroup classes and revealed a prediction of what genomic characteristics make an Ascomycete phytopathogenic. We conclude that genes shared by multiple phytopathogenic genomes are more important for phytopathogenicity than those that are unique in each genome.

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