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1.
Biotechnol J ; 19(3): e2300711, 2024 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-38528369

RESUMO

DNA ligases catalyze bond formation in the backbone of nucleic acids via the formation of a phosphodiester bond between adjacent 5' phosphates and 3' hydroxyl groups on one strand of the duplex. While DNA ligases preferentially ligate single breaks in double-stranded DNA (dsDNA), they are capable of ligating a multitude of other nucleic acid substrates like blunt-ended dsDNA, TA overhangs, short overhangs and various DNA-RNA hybrids. Here we report a novel DNA ligase from Cronobacter phage CR 9 (R2D Ligase) with an unexpected DNA-to-RNA ligation activity. The R2D ligase shows excellent efficiency when ligating DNA to either end of RNA molecules using a DNA template. Furthermore, we show that DNA can be ligated simultaneously to both the 5' and 3' ends of microRNA-like molecules in a single reaction mixture. Abortive adenylated side product formation is suppressed at lower ATP concentrations and the ligase reaction reaches near completion when ligating RNA-to-DNA or DNA-to-RNA. The ligation of a DNA strand to the 5'-PO4 2- end of RNA is unique among the commercially available ligases and may facilitate novel workflows in microRNA analysis, RNA sequencing and the preparation of chimeric guide DNA-RNA for gene editing applications.


Assuntos
DNA Ligases , MicroRNAs , DNA Ligases/química , DNA Ligases/metabolismo , Ligases , DNA/genética , Sequência de Bases
2.
APMIS ; 129(12): 711-716, 2021 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-34580908

RESUMO

The pharyngeal mucosa can be colonized with bacteria that have potential to cause pharyngotonsillitis. By the use of culturing techniques and PCR, we aimed to assess the prevalence of bacterial pharyngeal pathogens among healthy adolescents and young adults. We performed a cross-sectional study in a community-based cohort of 217 healthy individuals between 16 and 25 years of age. Samples were analyzed for Group A streptococci (GAS), Group C/G streptococci (SDSE), Fusobacterium necrophorum, and Arcanobacterium haemolyticum. Compared to culturing, the PCR method resulted in more frequent detection, albeit in most cases with low levels of DNA, of GAS (20/217 vs. 5/217; p < 0.01) and F. necrophorum (20/217 vs. 8/217; p < 0.01). Culturing and PCR yielded similar rates of SDSE detection (14/217 vs. 12/217; p = 0.73). Arcanobacterium haemolyticum was rarely detected (3/217), and only by PCR. Overall, in 25.3% (55/217) of these healthy adolescents and young adults at least one of these pathogens was detected, a rate that is higher than previously described. Further studies are needed before clinical adoption of PCR-based detection methods for pharyngeal bacterial pathogens, as our findings suggest a high incidence of asymptomatic carriage among adolescents and young adults without throat infections.


Assuntos
Bactérias/isolamento & purificação , Portador Sadio/epidemiologia , Faringe/microbiologia , Adolescente , Adulto , Estudos Transversais , Feminino , Fusobacterium necrophorum/isolamento & purificação , Humanos , Masculino , Prevalência , Reação em Cadeia da Polimerase em Tempo Real , Streptococcus pyogenes/isolamento & purificação , Adulto Jovem
3.
Microb Cell Fact ; 18(1): 197, 2019 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-31711487

RESUMO

BACKGROUND: Heterologous production of cold-adapted proteins currently represents one of the greatest bottlenecks in the ongoing bioprospecting efforts to find new enzymes from low-temperature environments, such as, the polar oceans that represent essentially untapped resources in this respect. In mesophilic expression hosts such as Escherichia coli, cold-adapted enzymes often form inactive aggregates. Therefore it is necessary to develop new low-temperature expression systems, including identification of new host organisms and complementary genetic tools. Psychrophilic bacteria, including Pseudoalteromonas haloplanktis, Shewanella and Rhodococcus erythropolis have all been explored as candidates for such applications. However to date none of these have found widespread use as efficient expression systems, or are commercially available. In the present work we explored the use of the sub-Arctic bacterium Aliivibrio wodanis as a potential host for heterologous expression of cold-active enzymes. RESULTS: We tested 12 bacterial strains, as well as available vectors, promoters and reporter systems. We used RNA-sequencing to determine the most highly expressed genes and their intrinsic promoters in A. wodanis. In addition we examined a novel 5'-fusion to stimulate protein production and solubility. Finally we tested production of a set of "difficult-to-produce" enzymes originating from various bacteria and one Archaea. Our results show that cold-adapted enzymes can be produced in soluble and active form, even in cases when protein production failed in E. coli due to the formation of inclusion bodies. Moreover, we identified a 60-bp/20-aa fragment from the 5'-end of the AW0309160_00174 gene that stimulates expression of Green Fluorescent Protein and improves production of cold-active enzymes when used as a 5'-fusion. A 25-aa peptide from the same protein enhanced secretion of a 25-aa-sfGFP fusion. CONCLUSIONS: Our results indicate the use of A. wodanis and associated genetic tools for low-temperature protein production and indicate that A. wodanis represents an interesting platform for further development of a protein production system that can promote further cold-enzyme discoveries.


Assuntos
Aliivibrio/genética , Proteínas de Bactérias/síntese química , Enzimas/síntese química , Expressão Gênica , Proteínas Recombinantes/síntese química , Regiões Árticas , Biotecnologia , Temperatura Baixa , Oceanos e Mares , Temperatura
4.
Genome Biol Evol ; 10(4): 1127-1131, 2018 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-29635365

RESUMO

We report here the complete genome sequences of seven Vibrio anguillarum strains isolated from multiple geographic locations, thus increasing the total number of genomes of finished quality to 11. The genomes were de novo assembled from long-sequence PacBio reads. Including draft genomes, a total of 44 V. anguillarum genomes are currently available in the genome databases. They represent an important resource in the study of, for example, genetic variations and for identifying virulence determinants. In this article, we present the genomes and basic genome comparisons of the 11 complete genomes, including a BRIG analysis, and pan genome calculation. We also describe some structural features of superintegrons on chromosome 2 s, and associated insertion sequence (IS) elements, including 18 new ISs (ISVa3 - ISVa20), both of importance in the complement of V. anguillarum genomes.


Assuntos
Elementos de DNA Transponíveis/genética , Vibrio/genética , Sequenciamento Completo do Genoma , Genoma Bacteriano/genética , Sequenciamento de Nucleotídeos em Larga Escala , Anotação de Sequência Molecular , Análise de Sequência de DNA
5.
PeerJ ; 5: e3461, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28717590

RESUMO

BACKGROUND: The ferric uptake regulator (Fur) is a transcription factor and the main regulator of iron acquisition in prokaryotes. When bound to ferric iron, Fur recognizes its DNA binding site and generally executes its function by repressing transcription of its target genes. Due to its importance in virulence, the Fur regulon is well studied for several model bacteria. In our previous work, we used computational predictions and microarray to gain insights into Fur-regulation in Aliivibrio salmonicida, and have identified a number of genes and operons that appear to be under direct control of Fur. To provide a more accurate and deeper global understanding of the biological role of Fur we have now generated an A. salmonicida fur knock-out strain and used RNA-sequencing to compare gene expression between the wild-type and fur null mutant strains. RESULTS: An A. salmonicida fur null mutant strain was constructed. Biological assays demonstrate that deletion of fur results in loss of fitness, with reduced growth rates, and reduced abilities to withstand low-iron conditions, and oxidative stress. When comparing expression levels in the wild-type and the fur null mutant we retrieved 296 differentially expressed genes distributed among 18 of 21 functional classes of genes. A gene cluster encoding biosynthesis of the siderophore bisucaberin represented the highest up-regulated genes in the fur null mutant. Other highly up-regulated genes all encode proteins important for iron acquisition. Potential targets for the RyhB sRNA was predicted from the list of down-regulated genes, and significant complementarities were found between RyhB and mRNAs of the fur, sodB, cysN and VSAL_I0422 genes. Other sRNAs with potential functions in iron homeostasis were identified. CONCLUSION: The present work provides by far the most comprehensive and deepest understanding of the Fur regulon in A. salmonicida to date. Our data also contribute to a better understanding of how Fur plays a key role in iron homeostasis in bacteria in general, and help to show how Fur orchestrates iron uptake when iron levels are extremely low.

7.
Mol Immunol ; 68(2 Pt A): 176-84, 2015 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-26343448

RESUMO

The important human gram positive bacterial pathogen Streptococcus pyogenes employs various virulence factors to promote inflammation and to facilitate invasive disease progression. In this study we explored the relation of the secreted streptococcal cysteine proteases IdeS and SpeB, and neutrophil (PMN) proteases. We found that SpeB is resistant to proteolytic attack in an inflammatory environment, emphasizing the importance of SpeB for streptococcal pathogenicity, while PMN enzymes and SpeB itself process the IgG degrading endopeptidase IdeS. Processing occurs as NH2-terminal cleavage of IdeS resulting in reduced immunorecognition of the protease by specific antibodies. While the endopeptidase retains IgG cleaving activity, its ability to suppress the generation of reactive oxygen species is abolished. We suggest that the cleavage of NH2-terminal peptides by SpeB and/or neutrophil proteases is a mechanism evolved to prevent early inactivation of this important streptococcal virulence factor, albeit at the cost of impaired functionality.


Assuntos
Anticorpos Antibacterianos/imunologia , Proteínas de Bactérias/imunologia , Exotoxinas/imunologia , Elastase de Leucócito/imunologia , Infecções Estreptocócicas/imunologia , Tonsilite/imunologia , Sequência de Aminoácidos , Anticorpos Antibacterianos/genética , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Exotoxinas/genética , Exotoxinas/metabolismo , Expressão Gênica , Interações Hospedeiro-Patógeno , Humanos , Imunoglobulina G/genética , Elastase de Leucócito/genética , Elastase de Leucócito/metabolismo , Dados de Sequência Molecular , Neutrófilos/enzimologia , Neutrófilos/imunologia , Proteólise , Espécies Reativas de Oxigênio/imunologia , Espécies Reativas de Oxigênio/metabolismo , Proteínas Recombinantes/genética , Proteínas Recombinantes/imunologia , Infecções Estreptocócicas/enzimologia , Infecções Estreptocócicas/genética , Infecções Estreptocócicas/patologia , Streptococcus pyogenes/enzimologia , Streptococcus pyogenes/genética , Streptococcus pyogenes/imunologia , Tonsilite/enzimologia , Tonsilite/genética , Tonsilite/patologia
8.
Ann Hematol ; 91(5): 679-685, 2012 May.
Artigo em Inglês | MEDLINE | ID: mdl-22048790

RESUMO

Previous studies have suggested that adherence to imatinib therapy can be an obstacle among patients with chronic myeloid leukemia (CML). We studied adherence to imatinib therapy among CML patients treated at the Sahlgrenska University Hospital. We identified all CML patients that were alive at the 1st of January 2010 (n = 70). Nineteen patients were excluded due to a history of allogenic hematopoietic stem cell transplantation, and nine were excluded due to treatment with other tyrosine kinase inhibitors. Thirty-eight out of 42 patients (90%) treated with imatinib accepted inclusion in the study. The patients were interviewed in a structured way, and adherence was evaluated in a standardized way using the nine-item Morisky Medication Adherence Scale that ranges from 1 to 13. A Morisky score ≤10 indicates nonadherence and ≥11 indicates adherence. In addition, predefined follow-up questions were asked to identify factors known to influence adherence to therapy. In contrast to previous studies, our patients showed good adherence to imatinib therapy with a mean Morisky score of 12.3 out of 13 (range, 9-13). The interviews revealed factors known to predict adherence to therapy, namely being well informed and having frequent contact with a single hematologist. Furthermore, the patients had easy access to the treating clinic and felt that they took part in decisions concerning their disease and treatment. We show that adherence to imatinib can be very good in CML patients, and we suggest that simple measures such as increased patient information and continuity of care will increase adherence in patients with CML.


Assuntos
Antineoplásicos/uso terapêutico , Leucemia Mielogênica Crônica BCR-ABL Positiva/tratamento farmacológico , Adesão à Medicação , Piperazinas/uso terapêutico , Inibidores de Proteínas Quinases/uso terapêutico , Pirimidinas/uso terapêutico , Adulto , Idoso , Idoso de 80 Anos ou mais , Benzamidas , Feminino , Seguimentos , Humanos , Mesilato de Imatinib , Leucemia Mielogênica Crônica BCR-ABL Positiva/genética , Masculino , Pessoa de Meia-Idade , Inquéritos e Questionários , Resultado do Tratamento
9.
Mol Immunol ; 45(12): 3347-53, 2008 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-18533265

RESUMO

The important human bacterial pathogen Streptococcus pyogenes has evolved a variety of mechanisms to evade the actions of the human immune system. M protein and M-like proteins are major virulence factors that bind with high affinity to the Fc-part of IgG. However, the contribution of non-immune binding of IgG to bacterial virulence is not fully established. Importantly, the capacity of S. pyogenes to bind IgG is limited and due to the presence of large amounts of IgG present in vivo, the majority of IgGFc binding sites at the streptococcal surface are likely to be occupied by non-specific IgG. S. pyogenes also secretes a highly effective IgG-endopeptidase, IdeS that inhibits phagocytic killing by cleavage of specific IgG creating F(ab')2 and 1/2Fc fragments. In the present work, IgG and 1/2Fc binding to the streptococcal surface was studied and correlated to IdeS activity. Binding of IgG to the streptococcal surface is shown to be equilibrium and thus not designed to mediate a lasting protection against specific antibodies. However, non-immune binding of IgG to the bacterial surface is followed by the proteolytic cleavage of the antibody by the IgG-endopeptidase IdeS. IdeS generated 1/2Fc fragments do not compete efficiently with intact IgG in binding to the bacterial surface and rapid dissociation of 1/2Fc allows binding of new IgG. Thus, a correlated binding and proteolytic cleavage of IgG also increases the probability that the bacteria can resist specific IgG, despite the presence of a large excess of non-specific IgG in the circulation. As a consequence of IdeS activity, circulating 1/2Fc fragments are generated. These 1/2Fc fragments were shown to be biological active by acting as priming agents for polymorphonuclear leucocytes, suggesting a new mechanism of immune evasion employed by S. pyogenes.


Assuntos
Proteínas de Bactérias/metabolismo , Fragmentos Fc das Imunoglobulinas/imunologia , Neutrófilos/citologia , Neutrófilos/imunologia , Bacteriólise , Humanos , Fragmentos Fc das Imunoglobulinas/isolamento & purificação , Fragmentos Fc das Imunoglobulinas/metabolismo , Imunoglobulina G/sangue , Viabilidade Microbiana , Ligação Proteica , Espécies Reativas de Oxigênio/metabolismo , Streptococcus pyogenes/imunologia
10.
Infect Immun ; 76(5): 2183-8, 2008 May.
Artigo em Inglês | MEDLINE | ID: mdl-18332209

RESUMO

IdeS, a secreted cysteine protease of the important human pathogen Streptococcus pyogenes, interferes with phagocytic killing by specifically cleaving the heavy chain of immunoglobulin G (IgG). Two allelic variants of the enzyme have been described, the IgG-specific endopeptidase, IdeS (or Mac-1) and Mac-2, a protein with only weak IgG endopeptidase activity, which has been suggested to interfere with opsonophagocytosis by blocking Fcgamma receptors of phagocytic cells. However, despite the fact that Mac-2 proteins interact with Fcgamma receptors, no inhibition of reactive oxygen species (ROS) production, opsonophagocytosis, or streptococcal killing by Mac-2 has been reported. In the present study, Mac-2 proteins are shown to contain IgG endopeptidase activity indistinguishable from the enzymatic activity exhibited by IdeS/Mac-1 proteins. The earlier reported weak IgG endopeptidase activity appears to be unique to Mac-2 of M28 serotype strains (Mac-2(M28)) and is most likely due to the formation of a disulfide bond between the catalytic site cysteine and a cysteine residue in position 257 of Mac-2(M28). Furthermore, Mac-2 proteins are shown to inhibit ROS production ex vivo, independently of the IgG endopeptidase activity of the proteins. Inhibition of ROS generation per se, however, was not sufficient to mediate streptococcal survival in bactericidal assays. Thus, in contrast to earlier studies, implicating separate functions for IdeS and Mac-2 protein variants, the current study suggests that Mac-2 and IdeS are bifunctional proteins, combining Fcgamma receptor binding and IgG endopeptidase activity. This finding implies a unique role for Mac-2 proteins of the M28 serotype, since this serotype has evolved and retained a Mac-2 protein lacking IgG endopeptidase activity.


Assuntos
Proteínas de Bactérias/metabolismo , Imunoglobulina G/metabolismo , Streptococcus pyogenes/enzimologia , Streptococcus pyogenes/fisiologia , Proteínas de Bactérias/genética , Humanos , Viabilidade Microbiana , Mutagênese Sítio-Dirigida , Espécies Reativas de Oxigênio/antagonistas & inibidores , Espécies Reativas de Oxigênio/metabolismo , Infecções Estreptocócicas/microbiologia , Streptococcus pyogenes/genética
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