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1.
Emerg Microbes Infect ; 9(1): 348-365, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32041484

RESUMO

The release of modified mosquitoes to suppress/replace vectors constitutes a promising tool for vector control and disease prevention. Evidence regarding these innovative modification techniques is scarce and disperse. This work conducted a systematic review, gathering and analysing research articles from PubMed and Biblioteca Virtual em Saúde databases whose results report efficacy and non-target effects of using modified insects for disease prevention, until 2016. More than 1500 publications were screened and 349 were analysed. Only 12/3.4% articles reported field-based evidence and 41/11.7% covered modification strategies' post-release efficacy. Variability in the effective results (90/25.7%) questioned its reproducibility in different settings. We also found publications reporting reversal outcomes 38/10.9%, (e.g. post-release increase of vector population). Ecological effects were also reported, such as horizontal transfer events (54/15.5%), and worsening pathogenesis induced by natural wolbachia (10/2.9%). Present work revealed promising outcomes of modifying strategies. However, it also revealed a need for field-based evidence mainly regarding epidemiologic and long-term impact. It pointed out some eventual irreversible and important effects that must not be ignored when considering open-field releases, and that may constitute constraints to generate the missing field evidence. Present work constitutes a baseline of knowledge, offering also a methodological approach that may facilitate future updates.


Assuntos
Animais Geneticamente Modificados , Controle de Mosquitos/métodos , Mosquitos Vetores/genética , Animais , Transferência Genética Horizontal , Mosquitos Vetores/microbiologia , Wolbachia
2.
mSphere ; 5(1)2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996416

RESUMO

Haemophilus influenzae colonizes the respiratory tract in humans and causes both invasive and noninvasive infections. Resistance to extended-spectrum cephalosporins in H. influenzae is rare in Europe. In this study, we defined acquired resistance gene loci and ftsI mutations in multidrug-resistant (MDR) and/or PBP3-mediated beta-lactam-resistant (rPBP3) H. influenzae strains, intending to understand the mode of spread of antibiotic resistance determinants in this species. Horizontal transfer of mobile genetic elements and transformation with resistance-conferring ftsI alleles were contributory. We found one small plasmid and three novel integrative conjugative elements (ICEs) which carry different combinations of resistance genes. Demonstration of transfer and/or ICE circular forms showed that the ICEs are functional. Two extensively MDR genetically unrelated H. influenzae strains (F and G) from the same geographical region shared an identical novel MDR ICE (Tn6686) harboring bla TEM-1, catA2-like, and tet(B). The first Nordic case of MDR H. influenzae septicemia, strain 0, originating from the same geographical area as these strains, had a similar resistance pattern but contained another ICE [Tn6687 with bla TEM-1, catP and tet(B)] with an overall structure quite similar to that of Tn6686. Comparison of the complete ftsI genes among rPBP3 strains revealed that the entire gene or certain regions of it are identical in genetically unrelated strains, indicating horizontal gene transfer. Our findings illustrate that H. influenzae is capable of acquiring resistance against a wide range of commonly used antibiotics through horizontal gene transfer, in terms of conjugative transfer of ICEs and transformation of chromosomal genes.IMPORTANCE Haemophilus influenzae colonizes the respiratory tract in humans and causes both invasive and noninvasive infections. As a threat to treatment, resistance against critically important antibiotics is on the rise in H. influenzae Identifying mechanisms for horizontal acquisition of resistance genes is important to understand how multidrug resistance develops. The present study explores the antimicrobial resistance genes and their context in beta-lactam-resistant H. influenzae with coresistance to up to four non-beta-lactam groups. The results reveal that this organism is capable of acquiring resistance to a wide range of commonly used antibiotics through conjugative transfer of mobile genetic elements and transformation of chromosomal genes, resulting in mosaic genes with a broader resistance spectrum. Strains with chromosomally mediated resistance to extended-spectrum cephalosporins, co-trimoxazole, and quinolones combined with mobile genetic elements carrying genes mediating resistance to ampicillin, tetracyclines, and chloramphenicol have been reported, and further dissemination of such strains represents a particular concern.


Assuntos
Farmacorresistência Bacteriana Múltipla/genética , Transferência Genética Horizontal , Haemophilus influenzae/efeitos dos fármacos , Haemophilus influenzae/genética , Alelos , Técnicas de Tipagem Bacteriana , Noruega , Filogenia , Plasmídeos/genética , Polimorfismo de Nucleotídeo Único , beta-Lactamas/farmacologia
3.
PLoS One ; 15(1): e0217255, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31931516

RESUMO

Natural competence allows bacteria to respond to environmental and nutritional cues by taking up free DNA from their surroundings, thus gaining both nutrients and genetic information. In the Gram-negative bacterium Haemophilus influenzae, the genes needed for DNA uptake are induced by the CRP and Sxy transcription factors in response to lack of preferred carbon sources and nucleotide precursors. Here we show that one of these genes, HI0659, encodes the antitoxin of a competence-regulated toxin-antitoxin operon ('toxTA'), likely acquired by horizontal gene transfer from a Streptococcus species. Deletion of the putative toxin (HI0660) restores uptake to the antitoxin mutant. The full toxTA operon was present in only 17 of the 181 strains we examined; complete deletion was seen in 22 strains and deletions removing parts of the toxin gene in 142 others. In addition to the expected Sxy- and CRP-dependent-competence promoter, HI0659/660 transcript analysis using RNA-seq identified an internal antitoxin-repressed promoter whose transcription starts within toxT and will yield nonfunctional protein. We propose that the most likely effect of unopposed toxin expression is non-specific cleavage of mRNAs and arrest or death of competent cells in the culture. Although the high frequency of toxT and toxTA deletions suggests that this competence-regulated toxin-antitoxin system may be mildly deleterious, it could also facilitate downregulation of protein synthesis and recycling of nucleotides under starvation conditions. Although our analyses were focused on the effects of toxTA, the RNA-seq dataset will be a useful resource for further investigations into competence regulation.


Assuntos
DNA/genética , Haemophilus influenzae/genética , Streptococcus/genética , Sistemas Toxina-Antitoxina/genética , Fatores de Transcrição/genética , Antitoxinas/genética , DNA/metabolismo , Escherichia coli/genética , Regulação Bacteriana da Expressão Gênica/genética , Transferência Genética Horizontal/genética , Óperon/genética , Regiões Promotoras Genéticas , Biossíntese de Proteínas/genética , Transativadores/genética , Transformação Bacteriana/genética
4.
mSphere ; 5(1)2020 Jan 29.
Artigo em Inglês | MEDLINE | ID: mdl-31996415

RESUMO

Dissemination of antibiotic resistance (AR) genes, often on plasmids, leads to antibiotic-resistant bacterial infections, which is a major problem for animal and public health. Bacterial conjugation is the primary route of AR gene transfer in the mammalian gastrointestinal tract. Significant gaps in knowledge about which gastrointestinal communities and host factors promote plasmid transfer remain. Here, we used Salmonella enterica serovar Kentucky strain CVM29188 carrying plasmid pCVM29188_146 (harboring streptomycin and tetracycline resistance genes) to assess plasmid transfer to Escherichia coli under in vitro conditions and in various mouse strains with a conventional or defined microbiota. As an initial test, the transfer of pCVM29188_146 to the E. coli strains was confirmed in vitro Colonization resistance and, therefore, a lack of plasmid transfer were found in wild-type mice harboring a conventional microbiota. Thus, mice harboring the altered Schaedler flora (ASF), or ASF mice, were used to probe for host factors in the context of a defined microbiota. To assess the influence of inflammation on plasmid transfer, we compared interleukin-10 gene-deficient 129S6/SvEv ASF mice (proinflammatory environment) to wild-type 129S6/SvEv ASF mice and found no difference in transconjugant yields. In contrast, the mouse strain influenced plasmid transfer, as C3H/HeN ASF mice had significantly lower levels of transconjugants than 129S6/SvEv ASF mice. Although gastrointestinal members were identical between the ASF mouse strains, a few differences from C3H/HeN ASF mice were detected, with C3H/HeN ASF mice having significantly lower abundances of ASF members 356 (Clostridium sp.), 492 (Eubacterium plexicaudatum), and 502 (Clostridium sp.) than 129S6/SvEv ASF mice. Overall, we demonstrate that microbiota complexity and mouse genetic background influence in vivo plasmid transfer.IMPORTANCE Antibiotic resistance is a threat to public health. Many clinically relevant antibiotic resistance genes are carried on plasmids that can be transferred to other bacterial members in the gastrointestinal tract. The current study used a murine model to study the transfer of a large antibiotic resistance plasmid from a foodborne Salmonella strain to a gut commensal E. coli strain in the gastrointestinal tract. We found that different mouse genetic backgrounds and a different diversity of microbial communities influenced the level of Escherichia coli that acquired the plasmid in the gastrointestinal tract. This study suggests that the complexity of the microbial community and host genetics influence plasmid transfer from donor to recipient bacteria.


Assuntos
Farmacorresistência Bacteriana/genética , Escherichia coli/genética , Microbioma Gastrointestinal , Plasmídeos/genética , Salmonella enterica/genética , Animais , Escherichia coli/efeitos dos fármacos , Feminino , Transferência Genética Horizontal , Intestinos/microbiologia , Masculino , Camundongos , Camundongos da Linhagem 129/genética , Camundongos Endogâmicos C3H/genética , Camundongos Knockout/genética , Salmonella enterica/efeitos dos fármacos
5.
J Med Microbiol ; 69(1): 82-86, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31904319

RESUMO

In recent years, Serratia marcescens has emerged as an important agent of hospital-acquired infections, such as pneumonia, urinary tract infection, septicaemia and meningitis, particularly in vulnerable patients. Compared to Klebsiella pneumoniae and Escherichia coli, S. marcescens is less commonly associated with bla KPC genes, yet few cases of plasmid transmission at the gastrointestinal level from K. pneumoniae carbapenemase (KPC)-producing Enterobacterales to S. marcescens have been described. Here we report a case of in vivo acquisition, during a 3-month period of hospitalization in the intensive care unit, of a bla KPC-3 gene carried by a pKpQIL-IT plasmid, and its probable transmission at the bronchial level among different species of Enterobacterales, including K. pneumoniae and S. marcescens. By using whole genome sequence analyses we were able provide insight into the dynamics of carbapenem-resistance determinants acquisition in the lower respiratory tract, a novel anatomical region for such plasmid transmission events, that usually involve the gastrointestinal tract. The co-presence at the same time of both wild-type and resistant Enterobacterales could have been the critical factor leading to the spread of plasmids harbouring carbapenem-resistance genes, of particular importance during surveillance screenings. The possibility of such an event may have significant consequences in terms of antimicrobial treatment, with a potential limitation of therapeutic options, thereby further complicating the clinical management of high-risk critically ill patients.


Assuntos
Proteínas de Bactérias/genética , Transferência Genética Horizontal , Klebsiella pneumoniae/enzimologia , Klebsiella pneumoniae/genética , Plasmídeos , Serratia marcescens/enzimologia , Serratia marcescens/genética , beta-Lactamases/genética , Adulto , Infecção Hospitalar/microbiologia , Humanos , Unidades de Terapia Intensiva , Infecções por Klebsiella/microbiologia , Masculino , Infecções Respiratórias/microbiologia , Infecções por Serratia/microbiologia , Sequenciamento Completo do Genoma
6.
Syst Appl Microbiol ; 43(1): 126026, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31706562

RESUMO

A collection of 18 previously unstudied strains isolated from root nodules of Genista germanica (German greenweed) grown in southeast Poland was evaluated for the level of genetic diversity using the BOX-PCR technique and the phylogenetic relationship based on both core (16S rRNA, dnaK, ftsA, glnII, gyrB, recA, rpoB) and nodulation (nodC and nodZ) gene sequences. Each of the 18 G. germanica root nodule isolates displayed unique BOX-PCR patterns, indicating their high level of genomic heterogeneity. Based on the comparative 16S rDNA sequence analysis, 12 isolates were affiliated to the Bradyrhizobium genus and the other strains were most similar to Rhizobium species. Phylogenetic analysis of the core gene sequences indicated that the studied Bradyrhizobium bacteria were most closely related to Bradyrhizobium japonicum, whereas Rhizobium isolates were most closely related to Rhizobium lusitanum and R. leguminosarum. The phylogenies of nodC and nodZ for the Rhizobium strains were incongruent with each other and with the phylogenies inferred from the core gene sequences. All Rhizobium nodZ gene sequences acquired in this study were grouped with the sequences of Bradyrhizobium strains. Some of the studied Rhizobium isolates were placed in the nodC phylogenetic tree together with reference Rhizobium species, while the others were closely related to Bradyrhizobium bacteria. The results provided evidence for horizontal transfer of nodulation genes between Bradyrhizobium and Rhizobium. However, the horizontal transfer of nod genes was not sufficient for Rhizobium strains to form nodules on G. germanica roots, suggesting that symbiotic genes have to be adapted to the bacterial genome.


Assuntos
Bradyrhizobium/genética , Genista/microbiologia , Nodulação/genética , Rhizobium/genética , Nódulos Radiculares de Plantas/microbiologia , Bactérias/classificação , Bactérias/genética , Bactérias/isolamento & purificação , Proteínas de Bactérias/genética , Bradyrhizobium/classificação , Bradyrhizobium/isolamento & purificação , DNA Bacteriano/genética , Transferência Genética Horizontal , Genes Essenciais/genética , Variação Genética , Especificidade de Hospedeiro , Filogenia , RNA Ribossômico 16S/genética , Rhizobium/classificação , Rhizobium/isolamento & purificação , Análise de Sequência de DNA , Simbiose/genética
7.
Mol Biol Evol ; 37(1): 44-57, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31504747

RESUMO

The mitochondrial genomes (mitogenomes) of plants are known to incorporate and accumulate DNA from intra- and extracellular donors. Despite the intimate relationships formed between flowing plants (angiosperms) and fungi, lengthy fungal-like sequence has not been identified in angiosperm mitogenomes to date. Here, we present multiple lines of evidence documenting horizontal gene transfer (HGT) between the mitogenomes of fungi and the ancestors of the orchids, plants that are obligate parasites of fungi during their early development. We show that the ancestor of the orchids acquired an ∼270-bp fungal mitogenomic region containing three transfer RNA genes. We propose that the short HGT was later replaced by a second HGT event transferring >8 kb and 14 genes from a fungal mitogenome to that of the ancestor of the largest orchid subfamily, Epidendroideae. Our results represent the first evidence of genomic-scale HGT between fungal and angiosperm mitogenomes and demonstrate that the length intergenic spacer regions of angiosperm mitogenomes can effectively fossilize the genomic remains of ancient, nonplant organisms.


Assuntos
Basidiomycota/genética , Transferência Genética Horizontal , Genoma Mitocondrial , Orchidaceae/genética , Genoma de Planta , Filogenia , Análise de Sequência de RNA
8.
Water Res ; 169: 115229, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31783256

RESUMO

Antibiotic resistance in bacteria is a growing threat to global human health. Horizontal gene transfer (HGT) of antibiotic resistance genes (ARGs) is recognized as the primary contributor to antibiotic resistance dissemination. Silver nanoparticles (AgNPs) are widely used in personal care products as antimicrobial agents. While heavy metals are known to induce antibiotic resistance in bacteria, it is not known whether AgNPs in the environment can stimulate the HGT of ARGs. Here, we report that both AgNPs and ionic silver Ag+, at environmentally relevant and sub-lethal concentrations, facilitate the conjugative transfer of plasmid-borne ARGs across bacterial genera (from the donor Escherichia coli K-12 LE392 to the recipient Pseudomonas putida KT2440). The underlying mechanisms of the Ag+- or AgNPs-promoted HGT were unveiled by detecting oxidative stress and cell membrane permeability, combined with genome-wide RNA sequencing and proteomic analyses. It was found that both Ag+ and AgNPs exposure induced various bacterial responses that included reactive oxygen species (ROS) generation, membrane damage and the SOS response. This study exposes the potential ecological risks of environmental levels of AgNPs and Ag+ for promoting the spread of ARGs and highlights concerns regarding the management of nanoparticles and heavy metals.


Assuntos
Escherichia coli K12 , Nanopartículas Metálicas , Antibacterianos , Resistência Microbiana a Medicamentos , Transferência Genética Horizontal , Humanos , Íons , Plasmídeos , Proteômica , Prata
9.
Sci Total Environ ; 698: 134236, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31493577

RESUMO

The widespread emergence of antibiotic resistance genes (ARGs) in drinking water systems endangers human health, and may be exacerbated by their horizontal gene transfer (HGT) among microbiota. In our previous study, Quorum sensing (QS) molecules produced by bacteria from biological activated carbon (BAC) biofilms were demonstrated to influence the transfer efficiency of a model conjugative plasmid, here RP4. In this study, we further explored the effect and mechanism of QS on conjugation transfer. The results revealed that Acyl-homoserine lactones producing (AHL-producing) bacteria isolated from BAC biofilm play a role in the propagation of ARGs. We selected several quorum sensing inhibitors (QSIs) to study their effects on AHL-producing bacteria, including the formation of biofilm and the regulating effect on conjugation transfer. In addition, the possible molecular mechanisms for AHLs that promote conjugative transfer were attributable to enhancing the mRNA expression, which involved altered expressions of conjugation-related genes. We also found that QSIs could inhibit conjugative transfer by downregulating the conjugation-relevant genes. We believe that this is the first insightful exploration of the mechanism by which AHLs will facilitate and QSIs will inhibit the conjugative transfer of ARGs. These results provide creative insight into ARG pollution control that involves blocking QS during BAC treatment in drinking water systems.


Assuntos
Acil-Butirolactonas/metabolismo , Biofilmes , Percepção de Quorum , Carvão Vegetal , Água Potável/microbiologia , Transferência Genética Horizontal , Plasmídeos
10.
Bioresour Technol ; 295: 122191, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31634801

RESUMO

The dynamics of antibiotic resistance genes (ARGs) response to ammonia stress were evaluated using metagenomics and quantitative PCR (qPCR) in anaerobic digestion (AD). Ammonia stress reduced ARGs associated with antibiotic efflux, especially the major facilitator superfamily (MFS) of tet(L), due to free ammonia (FA) that changed the proton gradient of efflux system. Nonetheless, ARGs of antibiotic target alteration, especially ermB, were enriched under ammonia stress, which could be attributed to the initiation of the internal enhancer of the transferability of the broad host range plasmid, pAMbeta1. Statistical analysis elucidated the significant changes of ARGs are directly attributed to the mobile genetic elements (MGEs), but the little affected ARGs are mainly determined by the functional microbes reflected by nitrogen cycling genes (NCyc). This study deciphered the profiles of ARGs response to ammonia stress in AD, which indicated the importance of alleviation of ammonia inhibition for the mitigation of ARGs dissemination.


Assuntos
Antibacterianos , Transferência Genética Horizontal , Amônia , Anaerobiose , Resistência Microbiana a Medicamentos , Genes Bacterianos
11.
ISME J ; 14(1): 259-273, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31624345

RESUMO

Many insects depend on obligate mutualistic bacteria to provide essential nutrients lacking from their diet. Most aphids, whose diet consists of phloem, rely on the bacterial endosymbiont Buchnera aphidicola to supply essential amino acids and B vitamins. However, in some aphid species, provision of these nutrients is partitioned between Buchnera and a younger bacterial partner, whose identity varies across aphid lineages. Little is known about the origin and the evolutionary stability of these di-symbiotic systems. It is also unclear whether the novel symbionts merely compensate for losses in Buchnera or carry new nutritional functions. Using whole-genome endosymbiont sequences of nine Cinara aphids that harbour an Erwinia-related symbiont to complement Buchnera, we show that the Erwinia association arose from a single event of symbiont lifestyle shift, from a free-living to an obligate intracellular one. This event resulted in drastic genome reduction, long-term genome stasis, and co-divergence with aphids. Fluorescence in situ hybridisation reveals that Erwinia inhabits its own bacteriocytes near Buchnera's. Altogether these results depict a scenario for the establishment of Erwinia as an obligate symbiont that mirrors Buchnera's. Additionally, we found that the Erwinia vitamin-biosynthetic genes not only compensate for Buchnera's deficiencies, but also provide a new nutritional function; whose genes have been horizontally acquired from a Sodalis-related bacterium. A subset of these genes have been subsequently transferred to a new Hamiltonella co-obligate symbiont in one specific Cinara lineage. These results show that the establishment and dynamics of multi-partner endosymbioses can be mediated by lateral gene transfers between co-ocurring symbionts.


Assuntos
Afídeos/microbiologia , Buchnera/genética , Erwinia/genética , Transferência Genética Horizontal , Simbiose/genética , Animais , Vitaminas/biossíntese
12.
BJOG ; 127(2): 129-137, 2020 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325209

RESUMO

The hologenome concept of evolution is discussed, with special emphasis placed upon the microbiome of women. The microbiome is dynamic, changing under different conditions, and differs between women and men. Genetic variation occurs not only in the host, but also in the microbiome by the acquisition of novel microbes, the amplification of specific microbes, and horizontal gene transfer. The majority of unique genes in human holobionts are found in microbiomes, and mothers are responsible for transferring most of these to their offspring during birth, breastfeeding, and physical contact. Thus, mothers are likely to be the primary providers of the majority of genetic information to offspring via mitochondria and the microbiome. TWEETABLE ABSTRACT: Microbiomes differ between women and men. Most genes in humans are in the microbiome. Mothers transfer most of these genes to offspring.


Assuntos
Adaptação Biológica/fisiologia , Adaptação Fisiológica/fisiologia , Transferência Genética Horizontal/genética , Interações entre Hospedeiro e Microrganismos/fisiologia , Microbiota/fisiologia , Mães , Adaptação Biológica/genética , Adaptação Fisiológica/genética , Adulto , Animais , Evolução Biológica , Evolução Molecular , Feminino , Especiação Genética , Variação Genética , Hereditariedade , Humanos , Masculino , Microbiota/genética , Plantas , Gravidez
13.
BMC Bioinformatics ; 20(Suppl 23): 702, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31881904

RESUMO

BACKGROUND: Horizontal Gene Transfer (HGT) refers to the transfer of genetic materials between organisms through mechanisms other than parent-offspring inheritance. HGTs may affect human health through a large number of microorganisms, especially the gut microbiomes which the human body harbors. The transferred segments may lead to complicated local genome structural variations. Details of the local genome structure can elucidate the effects of the HGTs. RESULTS: In this work, we propose a graph-based method to reconstruct the local strains from the gut metagenomics data at the HGT sites. The method is implemented in a package named LEMON. The simulated results indicate that the method can identify transferred segments accurately on reference sequences of the microbiome. Simulation results illustrate that LEMON could recover local strains with complicated structure variation. Furthermore, the gene fusion points detected in real data near HGT breakpoints validate the accuracy of LEMON. Some strains reconstructed by LEMON have a replication time profile with lower standard error, which demonstrates HGT events recovered by LEMON is reliable. CONCLUSIONS: Through LEMON we could reconstruct the sequence structure of bacteria, which harbors HGT events. This helps us to study gene flow among different microbial species.


Assuntos
Trato Gastrointestinal/microbiologia , Transferência Genética Horizontal/genética , Metagenômica , Software , Bactérias/genética , Simulação por Computador , Bases de Dados Genéticas , Fusão Gênica , Humanos , Transcriptoma/genética
14.
PLoS Genet ; 15(10): e1008445, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-31609967

RESUMO

Integrative and conjugative elements (ICEs) are widespread mobile DNA elements in the prokaryotic world. ICEs are usually retained within the bacterial chromosome, but can be excised and transferred from a donor to a new recipient cell, even of another species. Horizontal transmission of ICEclc, a prevalent ICE in proteobacteria, only occurs from developed specialized transfer competent (tc) cells in the donor population. tc cells become entirely dedicated to the ICE transmission at the cost of cell proliferation. The cell growth impairment is mediated by two ICEclc located genes, parA and shi, but the mechanistic and dynamic details of this process are unknown. To better understand the function of ParA and Shi, we followed their intracellular behavior from fluorescent protein fusions, and studied host cell division at single-cell level. Superresolution imaging revealed that ParA-mCherry colocalized with the host nucleoid while Shi-GFP was enriched at the membrane during the growth impairment. Despite being enriched at different cellular locations, the two proteins showed in vivo interactions, and mutations in the Walker A motif of ParA dislocalized both ParA and Shi. In addition, ParA mutations in the ATPase motif abolished the growth arrest on the host cell. Time-lapse microscopy revealed that ParA and Shi initially delay cell division, suggesting an extension of the S phase of cells, but eventually completely inhibit cell elongation. The parA-shi locus is highly conserved in other ICEclc-related elements, and expressing ParA-Shi from ICEclc in other proteobacterial species caused similar growth arrest, suggesting that the system functions similarly across hosts. The results of our study provide mechanistic insight into the novel and unique system on ICEs and help to understand such epistatic interaction between ICE genes and host physiology that entails efficient horizontal gene transfer.


Assuntos
Proteínas de Bactérias/genética , Divisão Celular/genética , Elementos de DNA Transponíveis/genética , Transferência Genética Horizontal , Pseudomonas putida/genética , Conjugação Genética , Loci Gênicos , Mutação , Pontos de Checagem da Fase S do Ciclo Celular/genética
15.
BMC Genomics ; 20(1): 761, 2019 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-31640552

RESUMO

BACKGROUND: Horizontal gene transfer (HGT), which is affected by environmental pollution and climate change, promotes genetic communication, changing bacterial pathogenicity and drug resistance. However, few studies have been conducted on the effect of HGT on the high pathogenicity and drug resistance of the opportunistic pathogen Vibrio harveyi. RESULTS: V. harveyi 345 that was multidrug resistant and infected Epinephelus oanceolutus was isolated from a diseased organism in Shenzhen, Southern China, an important and contaminated aquaculture area. Analysis of the entire genome sequence predicted 5678 genes including 487 virulence genes contributing to bacterial pathogenesis and 25 antibiotic-resistance genes (ARGs) contributing to antimicrobial resistance. Five ARGs (tetm, tetb, qnrs, dfra17, and sul2) and one virulence gene (CU052_28670) on the pAQU-type plasmid p345-185, provided direct evidence for HGT. Comparative genome analysis of 31 V. harveyi strains indicated that 217 genes and 7 gene families, including a class C beta-lactamase gene, a virulence-associated protein D gene, and an OmpA family protein gene were specific to strain V. harveyi 345. These genes could contribute to HGT or be horizontally transferred from other bacteria to enhance the virulence or antibiotic resistance of 345. Mobile genetic elements in 71 genomic islands encoding virulence factors for three type III secretion proteins and 13 type VI secretion system proteins, and two incomplete prophage sequences were detected that could be HGT transfer tools. Evaluation of the complete genome of V. harveyi 345 and comparative genomics indicated genomic exchange, especially exchange of pathogenic genes and drug-resistance genes by HGT contributing to pathogenicity and drug resistance. Climate change and continued environmental deterioration are expected to accelerate the HGT of V. harveyi, increasing its pathogenicity and drug resistance. CONCLUSION: This study provides timely information for further analysis of V. harveyi pathogenesis and antimicrobial resistance and developing pollution control measurements for coastal areas.


Assuntos
Resistência Microbiana a Medicamentos/genética , Transferência Genética Horizontal , Genoma Bacteriano/genética , Vibrio/genética , Vibrio/patogenicidade , Genes Bacterianos , Ilhas Genômicas/genética , Anotação de Sequência Molecular , Família Multigênica , Filogenia , Plasmídeos/genética , Prófagos/genética , Especificidade da Espécie , Vibrio/classificação , Vibrio/fisiologia , Virulência/genética , Fatores de Virulência
16.
Nat Commun ; 10(1): 4823, 2019 10 23.
Artigo em Inglês | MEDLINE | ID: mdl-31645564

RESUMO

The common ancestor of red algae (Rhodophyta) has undergone massive genome reduction, whereby 25% of the gene inventory has been lost, followed by its split into the species-poor extremophilic Cyanidiophytina and the broadly distributed mesophilic red algae. Success of the mesophile radiation is surprising given their highly reduced gene inventory. To address this latter issue, we combine an improved genome assembly from the unicellular red alga Porphyridium purpureum with a diverse collection of other algal genomes to reconstruct ancient endosymbiotic gene transfers (EGTs) and gene duplications. We find EGTs associated with the core photosynthetic machinery that may have played important roles in plastid establishment. More significant are the extensive duplications and diversification of nuclear gene families encoding phycobilisome linker proteins that stabilize light-harvesting functions. We speculate that the origin of these complex families in mesophilic red algae may have contributed to their adaptation to a diversity of light environments.


Assuntos
Fotossíntese/genética , Ficobilissomas/genética , Porphyridium/genética , Evolução Molecular , Duplicação Gênica , Transferência Genética Horizontal , Genomas de Plastídeos , Genômica , Filogenia , Plastídeos/genética , Rodófitas/genética , Simbiose
17.
Microbes Environ ; 34(4): 388-392, 2019 Dec 27.
Artigo em Inglês | MEDLINE | ID: mdl-31631079

RESUMO

Horizontal gene transfer (HGT) between bacteria with different habitats and nutritional requirements is important for the spread of antibiotic resistance genes (ARG). The objective of the present study was to clarify the effects of organic matter on HGT between nourished and starved bacteria. We demonstrated that conjugation ability is affected by the nutritional conditions of the cell and environment. A filter mating HGT experiment was performed using Photobacterium damselae ssp. damselae, strain 04Ya311, a marine-origin bacterium possessing the multidrug-resistance plasmid pAQU1, as the donor, and Escherichia coli as the recipient. The donor and recipient were both prepared as nutrient-rich cultured and starved cells. Filter mating was performed on agar plates with and without organic nutrients. The transcription of the plasmid-borne genes tet(M) and traI was quantitated under eutrophic and oligotrophic conditions. The donor P. damselae transferred the plasmid to E. coli at a transfer rate of 10-4 under oligotrophic and eutrophic conditions. However, when the donor was starved, HGT was not detected under oligotrophic conditions. The addition of organic matter to starved cells restored conjugative HGT even after 6 d of starvation. The transcription of traI was not detected in starved cells, but was restored upon the addition of organic matter. The HGT rate appears to be affected by the transcription of plasmid-associated genes. The present results suggest that the HGT rate is low in starved donors under oligotrophic conditions, but is restored by the addition of organic matter.


Assuntos
Escherichia coli/genética , Transferência Genética Horizontal/efeitos dos fármacos , Nutrientes/farmacologia , Photobacterium/genética , Conjugação Genética/efeitos dos fármacos , Meios de Cultura/química , Farmacorresistência Bacteriana Múltipla/genética , Escherichia coli/efeitos dos fármacos , Genes Bacterianos/genética , Nutrientes/análise , Photobacterium/efeitos dos fármacos , Plasmídeos/genética , Transcrição Genética/efeitos dos fármacos
18.
Ecotoxicol Environ Saf ; 186: 109781, 2019 Dec 30.
Artigo em Inglês | MEDLINE | ID: mdl-31622879

RESUMO

Nanomaterials of Al2O3 and TiO2 have been proved to promote the spread of antibiotic resistance genes (ARGs) by horizontal gene transfer. In this work, we found that Fe2O3@MoS2 nanocomposite inhibited the horizontal gene transfer (HGT) by inhibiting the conjugative transfer mediated by RP4-7 plasmid. To discover the mechanism of Fe2O3@MoS2 inhibiting HGT, the bacterial cells were collected under the optimal mating conditions. The collected bacterial cells were used for analyzing the expression levels of genes unique to the plasmid and the bacterial chromosome in the conjugation system by qPCR. The results of genes expression demonstrated that the mechanism of Fe2O3@MoS2 inhibited conjugation by promoting the expression of global regulatory gene (trbA) and inhibiting the expression of conjugative transfer genes involved in mating pair formation (traF, trbB) and DNA replication (trfA). The risk assessment of Fe2O3@MoS2 showed that it had very low toxicity to organisms. The findings of this paper showed that Fe2O3@MoS2, as an inhibitor of horizontal gene transfer, is an environment-friendly material.


Assuntos
Conjugação Genética/efeitos dos fármacos , Dissulfetos/química , Resistência Microbiana a Medicamentos/efeitos dos fármacos , Compostos Férricos/química , Transferência Genética Horizontal/efeitos dos fármacos , Molibdênio/química , Nanocompostos/química , Antibacterianos/farmacologia , Candida albicans/efeitos dos fármacos , Candida albicans/genética , Conjugação Genética/genética , Dissulfetos/farmacologia , Resistência Microbiana a Medicamentos/genética , Escherichia coli/efeitos dos fármacos , Escherichia coli/genética , Compostos Férricos/farmacologia , Genes Microbianos , Molibdênio/farmacologia , Plasmídeos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/genética
19.
Mol Biol Evol ; 36(12): 2737-2747, 2019 12 01.
Artigo em Inglês | MEDLINE | ID: mdl-31504731

RESUMO

Reverse gyrase (RG) is the only protein found ubiquitously in hyperthermophilic organisms, but absent from mesophiles. As such, its simple presence or absence allows us to deduce information about the optimal growth temperature of long-extinct organisms, even as far as the last universal common ancestor of extant life (LUCA). The growth environment and gene content of the LUCA has long been a source of debate in which RG often features. In an attempt to settle this debate, we carried out an exhaustive search for RG proteins, generating the largest RG data set to date. Comprising 376 sequences, our data set allows for phylogenetic reconstructions of RG with unprecedented size and detail. These RG phylogenies are strikingly different from those of universal proteins inferred to be present in the LUCA, even when using the same set of species. Unlike such proteins, RG does not form monophyletic archaeal and bacterial clades, suggesting RG emergence after the formation of these domains, and/or significant horizontal gene transfer. Additionally, the branch lengths separating archaeal and bacterial groups are very short, inconsistent with the tempo of evolution from the time of the LUCA. Despite this, phylogenies limited to archaeal RG resolve most archaeal phyla, suggesting predominantly vertical evolution since the time of the last archaeal ancestor. In contrast, bacterial RG indicates emergence after the last bacterial ancestor followed by significant horizontal transfer. Taken together, these results suggest a nonhyperthermophilic LUCA and bacterial ancestor, with hyperthermophily emerging early in the evolution of the archaeal and bacterial domains.


Assuntos
DNA Topoisomerases Tipo I/genética , Evolução Molecular , Origem da Vida , Filogenia , Transferência Genética Horizontal
20.
Cell Host Microbe ; 26(3): 385-399.e9, 2019 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-31513773

RESUMO

Parasitic protists belonging to the genus Leishmania synthesize the non-canonical carbohydrate reserve, mannogen, which is composed of ß-1,2-mannan oligosaccharides. Here, we identify a class of dual-activity mannosyltransferase/phosphorylases (MTPs) that catalyze both the sugar nucleotide-dependent biosynthesis and phosphorolytic turnover of mannogen. Structural and phylogenic analysis shows that while the MTPs are structurally related to bacterial mannan phosphorylases, they constitute a distinct family of glycosyltransferases (GT108) that have likely been acquired by horizontal gene transfer from gram-positive bacteria. The seven MTPs catalyze the constitutive synthesis and turnover of mannogen. This metabolic rheostat protects obligate intracellular parasite stages from nutrient excess, and is essential for thermotolerance and parasite infectivity in the mammalian host. Our results suggest that the acquisition and expansion of the MTP family in Leishmania increased the metabolic flexibility of these protists and contributed to their capacity to colonize new host niches.


Assuntos
Glicosiltransferases/classificação , Glicosiltransferases/metabolismo , Leishmania/enzimologia , Manosiltransferases/metabolismo , Fosforilases/classificação , Fosforilases/metabolismo , Cristalografia por Raios X , Transferência Genética Horizontal , Glicosiltransferases/química , Glicosiltransferases/genética , Mananas , Manosiltransferases/química , Manosiltransferases/genética , Modelos Moleculares , Oligossacarídeos , Fosforilases/química , Fosforilases/genética , Conformação Proteica , Termotolerância , Virulência
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