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1.
Appl Microbiol Biotechnol ; 105(18): 6607-6626, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34468804

RESUMEN

Bacillus subtilis is a well-characterized Gram-positive bacterium and a valuable host for recombinant protein production because of its efficient secretion ability, high yield, and non-toxicity. Here, we comprehensively review the recent studies on recombinant protein production in B. subtilis to update and supplement other previous reviews. We have focused on several aspects, including optimization of B. subtilis strains, enhancement and regulation of expression, improvement of secretion level, surface display of proteins, and fermentation optimization. Among them, optimization of B. subtilis strains mainly involves undirected chemical/physical mutagenesis and selection and genetic manipulation; enhancement and regulation of expression comprises autonomous plasmid and integrated expression, promoter regulation and engineering, and fine-tuning gene expression based on proteases and molecular chaperones; improvement of secretion level predominantly involves secretion pathway and signal peptide screening and optimization; surface display of proteins includes surface display of proteins on spores or vegetative cells; and fermentation optimization incorporates medium optimization, process condition optimization, and feeding strategy optimization. Furthermore, we propose some novel methods and future challenges for recombinant protein production in B. subtilis.Key points• A comprehensive review on recombinant protein production in Bacillus subtilis.• Novel techniques facilitate recombinant protein expression and secretion.• Surface display of proteins has significant potential for different applications.


Asunto(s)
Bacillus subtilis , Proteínas Bacterianas , Bacillus subtilis/genética , Proteínas Bacterianas/genética , Chaperonas Moleculares , Señales de Clasificación de Proteína , Proteínas Recombinantes/genética
2.
Braz J Biol ; 83: e246436, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34495159

RESUMEN

Application of different fertilizers to check the efficiency of expression of Bt (Bacillus thuringiensis) gene in one of the leading commercialized crops (cotton) against Lepidopteran species is of great concern. The expression of Cry protein level can be controlled by the improvement of nutrients levels. Therefore, the myth of response of Cry toxin to different combinations of NP fertilizers was explored in three Bt cotton cultivars. Combinations include three levels of nitrogen and three levels of phosphorus fertilizers. Immunostrips and Cry gene(s) specific primer based PCR (Polymerase Chain Reaction) analysis were used for the presence of Bt gene that unveiled the presence of Cry1Ac gene only. Further, the ELISA (enzyme-linked immunosorbent assay) kit was used to quantify the expression of Cry1Ac protein. Under various NP fertilizers rates, the level of toxin protein exhibited highly significant differences. The highest toxin level mean was found to be 2.3740 and 2.1732 µg/g under the treatment of N150P75 kg ha-1 combination while the lowest toxin level mean was found to be 0.9158 and 0.7641 µg/g at the N50P25 kg ha-1 level at 80 and 120 DAS (Days After Sowing), respectively. It was concluded from the research that the usage of NP fertilizers has a positive relation with the expression of Cry1Ac toxin in Bt cotton. We recommend using the N150P50 kg ha-1 level as the most economical and practicable fertilizer instead of the standard dose N100P50 kg ha-1 to get the desired level of Cry1Ac level for long lasting plant resistance (<1.5). The revised dose of fertilizer may help farmers to avoid the cross-resistance development in contradiction of insect pests.


Asunto(s)
Proteínas Hemolisinas , Mariposas Nocturnas , Animales , Toxinas de Bacillus thuringiensis , Proteínas Bacterianas/genética , Endotoxinas/genética , Fertilizantes , Proteínas Hemolisinas/genética , Resistencia a los Insecticidas , Larva , Nitrógeno , Fósforo , Plantas Modificadas Genéticamente/genética
3.
Euro Surveill ; 26(36)2021 09.
Artículo en Inglés | MEDLINE | ID: mdl-34505571

RESUMEN

We identified a novel van gene cluster in a clinical Enterococcus faecium isolate with vancomycin minimum inhibitory concentration (MIC) of 4 µg/mL. The ligase gene, vanP, was part of a van operon cluster of 4,589 bp on a putative novel integrative conjugative element located in a ca 98 kb genomic region presumed to be acquired by horizontal gene transfer from Clostridium scidens and Roseburia sp. 499. Screening for van genes in E. faecium strains with borderline susceptibility to vancomycin is important.


Asunto(s)
Enterococcus faecium , Antibacterianos/farmacología , Proteínas Bacterianas/genética , Bélgica , Enterococcus faecium/genética , Humanos , Familia de Multigenes , Resistencia a la Vancomicina/genética
4.
Front Cell Infect Microbiol ; 11: 692224, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34368013

RESUMEN

The chlamydial small non coding RNA, IhtA, regulates the expression of both HctA and DdbA, the uncharacterized product of the C. trachomatis L2 CTL0322 gene. HctA is a small, highly basic, DNA binding protein that is expressed late in development and mediates the condensation of the genome during RB to EB differentiation. DdbA is conserved throughout the chlamydial lineage, and is predicted to express a small, basic, cytoplasmic protein. As it is common for sRNAs to regulate multiple mRNAs within the same physiological pathway, we hypothesize that DdbA, like HctA, is involved in RB to EB differentiation. Here, we show that DdbA is a DNA binding protein, however unlike HctA, DdbA does not contribute to genome condensation but instead likely has nuclease activity. Using a DdbA temperature sensitive mutant, we show that DdbAts creates inclusions indistinguishable from WT L2 in size and that early RB replication is likewise similar at the nonpermissive temperature. However, the number of DdbAts infectious progeny is dramatically lower than WT L2 overall, although production of EBs is initiated at a similar time. The expression of a late gene reporter construct followed live at 40°C indicates that late gene expression is severely compromised in the DdbAts strain. Viability assays, both in host cells and in axenic media indicate that the DdbAts strain is defective in the maintenance of EB infectivity. Additionally, using Whole Genome Sequencing we demonstrate that chromosome condensation is temporally separated from DNA replication during the RB to EB transition. Although DdbA does not appear to be directly involved in this process, our data suggest it is a DNA binding protein that is important in the production and maintenance of infectivity of the EB, perhaps by contributing to the remodeling of the EB chromosome.


Asunto(s)
Chlamydia trachomatis , Regulación Bacteriana de la Expresión Génica , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Chlamydia trachomatis/genética , Chlamydia trachomatis/metabolismo , Proteínas de Unión al ADN/genética , Cuerpos de Inclusión/metabolismo
5.
Zhonghua Yi Xue Za Zhi ; 101(31): 2478-2484, 2021 Aug 17.
Artículo en Chino | MEDLINE | ID: mdl-34399563

RESUMEN

Objective: To characterize the antibiotic resistance and virulence in a carbapenem-resistant Klebsiella pneumoniae (CRKP). Methods: A CRKP (designated K. pneumoniae C35) was isolated from a stool sample. The minimal inhibitory concentrations of antimicrobial agents were determined using the broth microdilution method. Whole-genome sequencing and genome analysis were performed to identify the antibiotic resistance and virulence genes. The genetic relationship among K. pneumoniae C35 and other CRKP isolates from our hospital was analyzed by single nucleotide polymorphism (SNP) typing of core genomes. Conjugation experiments were carried out by filter mating to evaluate the transferability and efficiency of resistance genes. The virulence phenotype was determined by Galleria mellonella infection model. Results: K. pneumoniae C35 exhibited resistance to the majority of tested antibiotics, especially carbapenems, sulbactam, and polymyxins. SNP typing showed that K. pneumoniae C35 shared a high degree of sequence homology with several CRKP isolates from different wards. This ST11 CRKP carried 13 resistance genes, including blaKPC-2, blaCTX-M-199, mcr-1, and tet(A) variant. blaKPC-2 gene was located on an IncFⅡ plasmid with>69 800 bp in size, blaCTX-M-199 and mcr-1 genes were located on an IncI2 plasmid (>64 800 bp), and tet(A) variant was located on an unknown Inc-type plasmid (83 628bp). All these three plasmids were conjugative. K. pneumoniae C35 was found to harbor rmpA, rmpA2, and iucABCD aerobactin-related genes, and was considered to be classic carbapenem-resistant hypervirulent K. pneumoniae (CR-hvKP). The virulence potential of this strain was confirmed in a Galleria mellonella infection model. The survival rate of the larvae injected with strain C35 at 48 h after infection was significantly lower than that of negative control strain (16.7% vs 80.0%). Conclusion: Multiple conjugative plasmids are identified in a faecal CR-hvKP. The IncI2 plasmid co-carrying both blaCTX-M-199 and mcr-1 genes is firstly identified in CR-hvKP. The emergence of such strain should be alerted and active surveillance is warranted.


Asunto(s)
Infecciones por Klebsiella , Klebsiella pneumoniae , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Proteínas Bacterianas/genética , Carbapenémicos/farmacología , Farmacorresistencia Microbiana , Humanos , Infecciones por Klebsiella/tratamiento farmacológico , Klebsiella pneumoniae/genética , Tipificación de Secuencias Multilocus , Plásmidos/genética , Virulencia/genética , beta-Lactamasas
6.
Front Cell Infect Microbiol ; 11: 698146, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34368016

RESUMEN

L-arabinose inducible promoters are commonly used in gene expression analysis. However, nutrient source and availability also play a role in biofilm formation; therefore, L-arabinose metabolism could impact biofilm development. In this study we examined the impact of L-arabinose on Salmonella enterica serovar Typhimurium (S. Typhimurium) biofilm formation. Using mutants impaired for the transport and metabolism of L-arabinose, we showed that L-arabinose metabolism negatively impacts S. Typhimurium biofilm formation in vitro. When L-arabinose metabolism is abrogated, biofilm formation returned to baseline levels. However, without the ability to import extracellular L-arabinose, biofilm formation significantly increased. Using RNA-Seq we identified several gene families involved in these different phenotypes including curli expression, amino acid synthesis, and L-arabinose metabolism. Several individual candidate genes were tested for their involvement in the L-arabinose-mediated biofilm phenotypes, but most played no significant role. Interestingly, in the presence of L-arabinose the diguanylate cyclase gene adrA was downregulated in wild type S. Typhimurium. Meanwhile cyaA, encoding an adenylate cyclase, was downregulated in an L-arabinose transport mutant. Using an IPTG-inducible plasmid to deplete c-di-GMP via vieA expression, we were able to abolish the increased biofilm phenotype seen in the transport mutant. However, the mechanism by which the L-arabinose import mutant forms significantly larger biofilms remains to be determined. Regardless, these data suggest that L-arabinose metabolism influences intracellular c-di-GMP levels and therefore biofilm formation. These findings are important when considering the use of an L-arabinose inducible promoter in biofilm conditions.


Asunto(s)
Arabinosa , Proteínas Bacterianas , Biopelículas , Salmonella typhimurium , Arabinosa/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , GMP Cíclico , Regulación Bacteriana de la Expresión Génica , Plásmidos , Salmonella typhimurium/genética , Salmonella typhimurium/metabolismo
7.
Ecotoxicol Environ Saf ; 223: 112557, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34343899

RESUMEN

The impact of transgenic crops on non-target organisms is a key aspect of environmental safety assessment to transgenic crops. In the present study, we fed two snail species, Bradybaena (Acusta) ravida (B. ravida) and Bradybaena similaris (Ferussac)(B. similaris), with the leaves of transgenic Bt cotton Zhong 30 (Z30) and control cotton, its parent line zhong 16 (Z16), to assess the environmental safety of Bt cotton to common non-target organisms in the field. Survival, body weight, shell diameter, helix number, reproduction rate, superoxide dismutase (SOD) activity and Bt protein concentration in snails were monitored in 15 days and 180 days experiments. We also monitored the population dynamics of B. ravida and B. similaris in Z30 and Z16 cotton fields for two successive years. Compared to the snails fed on the control cotton Z16, there was no significant difference in survival, growth, reproduction, and SOD activity on Bt cotton Z30. Bt protein concentrations were significantly between different treatments, and Bt protein residues were only detected in the feces of the Z30 treatment. According to the field data, the number of B. ravida and B. similaris fluctuated considerably across seasons over the entire cotton-growing season; however, there were no significant differences between the Bt and control cotton fields at similar time. As the results showed, in our experiments, Bt cotton Z30 had no adverse effects on the two snail species, both in the laboratory and in the fields.


Asunto(s)
Productos Agrícolas , Caracoles , Animales , Animales Modificados Genéticamente , Proteínas Bacterianas/genética , Endotoxinas/genética , Endotoxinas/toxicidad , Gossypium/genética , Proteínas Hemolisinas/genética , Plantas Modificadas Genéticamente , Reproducción , Caracoles/genética
8.
Ecotoxicol Environ Saf ; 223: 112569, 2021 Oct 15.
Artículo en Inglés | MEDLINE | ID: mdl-34352582

RESUMEN

Transgenic-Bacillus thuringiensis (Bt) crops express insecticidal proteins, which can accumulate in plants and soil where they may influence microbial populations. The impact of Bt crops on bacterial communities has only been assessed under short-term, and results have been contradictory. Here, we analyzed the bacterial communities in three niches, rhizosphere soil (RS), root endosphere (RE) and leaf endosphere (LE), of three Bt rice and their non-Bt parental lines for three consecutive years by high-throughput sequencing. In principal coordinate analysis (PCoA) and PERMANOVA (Adonis) analysis, operational taxonomic units (OTUs) were clustered primarily by niche type and differed significantly in the RE and LE but not in the RS between each of three Bt lines compared with the non-Bt rice line, and not in each respective niche among the three Bt rice lines. The bacterial communities in the RS of different rice lines over the 3 years were clustered mainly by year rather than by lines. The differential bacterial taxa among the lines did not overlap between years, presumably because Cry proteins are rapidly degraded in the soil. A network analysis of RS bacterial communities showed that the network complexity and density for the three Bt rice lines did not decrease compared with those for the non-Bt line. In conclusion, our results demonstrated that bacterial communities differed significantly in RE and LE between Bt and non-Bt rice lines, but the differences were mild and transient, and had no adverse impact on RS over the 3 years. This study provides favorable evidence in support of the commercialization of Bt rice.


Asunto(s)
Bacillus thuringiensis , Oryza , Bacillus thuringiensis/genética , Proteínas Bacterianas/genética , Endotoxinas/genética , Proteínas Hemolisinas/genética , Oryza/genética , Plantas Modificadas Genéticamente , Rizosfera
9.
Structure ; 29(8): 781-782, 2021 08 05.
Artículo en Inglés | MEDLINE | ID: mdl-34358463

RESUMEN

The bacterial Sec translocase transports unfolded proteins across membranes. In this issue of Structure, Krishnamurthy et al. (2021) report a nexus of conformational dynamics in the translocase motor protein, SecA. Their findings shed light on the Sec activation mechanism and suggest a general role for multi-level dynamics in protein functions.


Asunto(s)
Proteínas Bacterianas , Proteínas de Transporte de Membrana , Adenosina Trifosfatasas/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Proteínas de Transporte de Membrana/genética , Proteínas de Transporte de Membrana/metabolismo , Transporte de Proteínas , Canales de Translocación SEC/genética , Proteína SecA
10.
Nat Commun ; 12(1): 4748, 2021 08 06.
Artículo en Inglés | MEDLINE | ID: mdl-34362927

RESUMEN

Encapsulins are a class of microbial protein compartments defined by the viral HK97-fold of their capsid protein, self-assembly into icosahedral shells, and dedicated cargo loading mechanism for sequestering specific enzymes. Encapsulins are often misannotated and traditional sequence-based searches yield many false positive hits in the form of phage capsids. Here, we develop an integrated search strategy to carry out a large-scale computational analysis of prokaryotic genomes with the goal of discovering an exhaustive and curated set of all HK97-fold encapsulin-like systems. We find over 6,000 encapsulin-like systems in 31 bacterial and four archaeal phyla, including two novel encapsulin families. We formulate hypotheses about their potential biological functions and biomedical relevance, which range from natural product biosynthesis and stress resistance to carbon metabolism and anaerobic hydrogen production. An evolutionary analysis of encapsulins and related HK97-type virus families shows that they share a common ancestor, and we conclude that encapsulins likely evolved from HK97-type bacteriophages.


Asunto(s)
Bacteriófagos/metabolismo , Cápside/metabolismo , Células Procariotas/metabolismo , Células Procariotas/virología , Archaea/metabolismo , Bacterias/metabolismo , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Bacteriófagos/genética , Evolución Biológica , Vías Biosintéticas/genética , Proteínas de la Cápside/química , Proteínas de la Cápside/metabolismo , Virus ADN/metabolismo , Filogenia , Virulencia
11.
Yi Chuan ; 43(8): 747-757, 2021 Aug 20.
Artículo en Chino | MEDLINE | ID: mdl-34413015

RESUMEN

The Cpx (conjugative pilus expression) two-component signal transduction system is a complex envelope stress response system in Gram-negative bacteria, which can sense a variety of extracellular stimuli that enter the signaling pathway at different points. The phosphorylation of the CpxR, the cytoplasmic cognate response regulator of the Cpx system, can lead to changes in the expression of genes encoding proteins involved in inner and outer membrane functions. Activation of the Cpx system contributes to bacterial resistance/tolerance to certain antibiotics and acidic stress. In this review, we summarize the composition, and the mechanisms of signal detection, and the transcriptional regulation of the Cpx system, with a goal to provide guidance for the study of the regulatory network of the Cpx system and its important regulatory roles in bacterial physiology.


Asunto(s)
Proteínas Bacterianas , Transducción de Señal , Proteínas Bacterianas/genética , Bacterias Gramnegativas
12.
Int J Med Microbiol ; 311(6): 151525, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34340061

RESUMEN

Recently, multiple bifunctional RNAs have been discovered, which can both be translated into proteins and play regulatory roles. hns encodes the global gene silencing factor H-NS, which is widespread in Gram-negative bacteria. This study reported that hns mRNA of Salmonella enterica serovar Typhi (S. Typhi) was a bifunctional RNA that could act as an antisense RNA downregulating the expression of galU, the coding gene of uridine triphosphate-glucose-1-phosphate uridylyltransferase, and attenuating bacterial motility. galU, which is located at the opposite strand of hns, was identified to have a long 3'-untranslated region that overlapped with hns and could be processed to produce short RNA fragments. The overexpression of hns mRNA inhibited the expression of galU. The deletion of galU attenuated the motility of S. Typhi, while the complementation of galU nearly restored the phenotype. Overexpressing hns mRNA in the wild-type strain of S. Typhi inhibited the motility and the expression of flagellar genes, while overexpressing hns mRNA in the galU-deletion mutant did not influence bacterial motility. In conclusion, hns mRNA has been identified to be a new bifunctional RNA that attenuates the motility of S. Typhi by downregulating the expression of galU.


Asunto(s)
Salmonella typhi , UTP-Glucosa-1-Fosfato Uridililtransferasa , Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica , ARN Mensajero/genética , Salmonella typhi/genética
13.
Appl Microbiol Biotechnol ; 105(14-15): 5943-5957, 2021 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-34350477

RESUMEN

Bacillus cereus 905, originally isolated from wheat rhizosphere, exhibits strong colonization ability on wheat roots. Our previous studies showed that root colonization is contributed by the ability of the bacterium to efficiently utilize carbon sources and form biofilms and that the sodA2 gene-encoded manganese-containing superoxide dismutase (MnSOD2) plays an indispensable role in the survival of B. cereus 905 in the wheat rhizosphere. In this investigation, we further demonstrated that the ability of B. cereus 905 to resist adverse environmental conditions is partially attributed to activation of the alternative sigma factor σB, encoded by the sigB gene. The sigB mutant experienced a dramatic reduction in survival when cells were exposed to ethanol, acid, heat, and oxidative stress or under glucose starvation. Analysis of the sodA2 gene transcription revealed a partial, σB-dependent induction of the gene during glucose starvation or when treated with paraquat. In addition, the sigB mutant displayed a defect in biofilm formation under stress conditions. Finally, results from the root colonization assay indicated that sigB and sodA2 collectively contribute to B. cereus 905 colonization on wheat roots. Our study suggests a diverse role of SigB in rhizosphere survival and root colonization of B. cereus 905 under stress conditions. KEY POINTS : • SigB confers resistance to environmental stresses in B. cereus 905. • SigB plays a positive role in glucose utilization and biofilm formation in B. cereus. • SigB and SodA2 collectively contribute to colonization on wheat roots by B. cereus.


Asunto(s)
Bacillus cereus , Glucosa , Bacillus cereus/genética , Proteínas Bacterianas/genética , Biopelículas , Factor sigma , Superóxido Dismutasa
14.
Adv Protein Chem Struct Biol ; 127: 343-364, 2021.
Artículo en Inglés | MEDLINE | ID: mdl-34340773

RESUMEN

BACKGROUND AND AIM: The persistence of extensively drug-resistant (XDR) strains of Mycobacterium tuberculosis (MTB) continue to pose a significant challenge to the treatment and control of tuberculosis infections worldwide. XDR-MTB strains exhibit resistance against first-line anti-TB drugs, fluoroquinolones, and second-line injectable drugs. The mechanisms of drug resistance of MTB remains poorly understood. Our study aims at identifying the differentially expressed genes (DEGs), associated gene networks, and signaling cascades involved in rendering this pathogen resistant to multiple drugs, namely, isoniazid, rifampicin, and capreomycin. METHODS: We used the microarray dataset GSE53843. The GEO2R tool was used to prioritize the most significant DEGs (top 250) of each drug exposure sample between XDR strains and non-resistant strains. The validation of the 250 DEGs was performed using volcano plots. Protein-protein interaction networks of the DEGs were created using STRING and Cytoscape tools, which helped decipher the relationship between these genes. The significant DEGs were functionally annotated using DAVID and ClueGO. The concomitant biological processes (BP) and molecular functions (MF) were represented as dot plots. RESULTS AND CONCLUSION: We identified relevant molecular pathways and biological processes, such as cell wall biogenesis, lipid metabolic process, ion transport, phosphopantetheine binding, and triglyceride lipase activity. These processes indicated the involvement of multiple interconnected mechanisms in drug resistance. Our study highlighted the impact of cell wall permeability, with the dysregulation of the mur family of proteins, as essential factors in the inference of resistance. Additionally, upregulation of genes responsible for ion transport such as ctpF, arsC, and nark3, emphasizes the importance of transport channels and efflux pumps in potentially driving out stress-inducing compounds. This study investigated the upregulation of the Lip family of proteins, which play a crucial role in triglyceride lipase activity. Thereby illuminating the potential role of drug-induced dormancy and subsequent resistance in the mycobacterial strains. Multiple mechanisms such as carboxylic acid metabolic process, NAD biosynthetic process, triglyceride lipase activity, phosphopantetheine binding, organic acid biosynthetic process, and growth of symbiont in host cell were observed to partake in resistance of XDR-MTB. This study ultimately provides a platform for important mapping targets for potential therapeutics against XDR-MTB.


Asunto(s)
Proteínas Bacterianas , Farmacorresistencia Bacteriana/genética , Tuberculosis Extensivamente Resistente a Drogas , Regulación Bacteriana de la Expresión Génica , Mycobacterium tuberculosis , Biología de Sistemas , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Tuberculosis Extensivamente Resistente a Drogas/genética , Tuberculosis Extensivamente Resistente a Drogas/metabolismo , Humanos
15.
Clin Lab ; 67(8)2021 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-34383413

RESUMEN

BACKGROUND: To investigate the distribution of virulence genes exoS and exoU of Pseudomonas aeruginosa type III secretion system and their antimicrobial resistance characteristics in Xinjiang Province. METHODS: A total of 228 isolates of Pseudomonas aeruginosa were collected from January 2017 to April 2017 in our hospital. The VITEK2-compac system was used for strain identification and antimicrobial susceptibility test. The disk diffusion method was used for antimicrobial susceptibility supplementation. PCR method was used for detection of exoS and exoU virulence gene. RESULTS: Among 228 isolates of Pseudomonas aeruginosa, 178 (78.07%) were positive for exoS gene, 91 (39.91%) were positive for exoU gene, and 21.49% of the isolates carried both genes (exoU+/exoS+). A total of 30 MDR strains were detected, accounting for 13.16%. The antimicrobial resistance of the exoU+ group was 76.67%, which was significantly higher than that of the exoU-group (23.33%). The difference was statistically significant (p < 0.001). The detection rate of fluoroquinolone-insensitive strains in exoU+ group was as high as 57.45%, which was significantly higher than 42.55% in exoU-group and the difference was statistically significant (p < 0.05). The 30-day mortality rate of the exoU+ group was 8.79%, which was higher than that of the exoU-group (4.38%), and the difference was statistically significant (p < 0.05). CONCLUSIONS: The expression of exoU gene is associated with multidrug resistance, fluoroquinolone resistance, and prognosis. We should enhance the detection of drug resistance and study the pathogenesis and regulation mecha-nism of T3SS, in order to provide new ideas for the design of reasonable treatment strategies and the development of new therapeutic drugs.


Asunto(s)
Infecciones por Pseudomonas , Pseudomonas aeruginosa , Antibacterianos/farmacología , Antibacterianos/uso terapéutico , Proteínas Bacterianas/genética , Genotipo , Humanos , Infecciones por Pseudomonas/diagnóstico , Infecciones por Pseudomonas/tratamiento farmacológico , Pseudomonas aeruginosa/genética , Sistemas de Secreción Tipo III/genética , Virulencia/genética , Factores de Virulencia/genética
16.
Nat Commun ; 12(1): 4707, 2021 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-34349110

RESUMEN

Salmonella utilizes translocated virulence proteins (termed effectors) to promote host cell invasion. The effector SopD contributes to invasion by promoting scission of the plasma membrane, generating Salmonella-containing vacuoles. SopD is expressed in all Salmonella lineages and plays important roles in animal models of infection, but its host cell targets are unknown. Here we show that SopD can bind to and inhibit the small GTPase Rab10, through a C-terminal GTPase activating protein (GAP) domain. During infection, Rab10 and its effectors MICAL-L1 and EHBP1 are recruited to invasion sites. By inhibiting Rab10, SopD promotes removal of Rab10 and recruitment of Dynamin-2 to drive scission of the plasma membrane. Together, our study uncovers an important role for Rab10 in regulating plasma membrane scission and identifies the mechanism used by a bacterial pathogen to manipulate this function during infection.


Asunto(s)
Proteínas Bacterianas/metabolismo , Membrana Celular/metabolismo , Salmonella typhimurium/patogenicidad , Proteínas de Unión al GTP rab/antagonistas & inhibidores , Proteínas Bacterianas/genética , Dinamina II , Proteínas Activadoras de GTPasa/genética , Proteínas Activadoras de GTPasa/metabolismo , Células HEK293 , Humanos , Salmonella typhimurium/metabolismo , Vacuolas/metabolismo , Vacuolas/microbiología , Virulencia , Proteínas de Unión al GTP rab/genética , Proteínas de Unión al GTP rab/metabolismo
17.
Int J Mol Sci ; 22(15)2021 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-34360611

RESUMEN

Due to the high exposition to changing environmental conditions, bacteria have developed many mechanisms enabling immediate adjustments of gene expression. In many cases, the required speed and plasticity of the response are provided by RNA-dependent regulatory mechanisms. This is possible due to the very high dynamics and flexibility of an RNA structure, which provide the necessary sensitivity and specificity for efficient sensing and transduction of environmental signals. In this review, we will discuss the current knowledge about known bacterial regulatory mechanisms which rely on RNA structure. To better understand the structure-driven modulation of gene expression, we describe the basic theory on RNA structure folding and dynamics. Next, we present examples of multiple mechanisms employed by RNA regulators in the control of bacterial transcription and translation.


Asunto(s)
Bacterias/genética , Proteínas Bacterianas/metabolismo , Regulación Bacteriana de la Expresión Génica , Conformación de Ácido Nucleico , Pliegue del ARN , ARN Bacteriano/química , Bacterias/crecimiento & desarrollo , Bacterias/metabolismo , Proteínas Bacterianas/genética , Transcripción Genética
18.
Int J Mol Sci ; 22(15)2021 Jul 22.
Artículo en Inglés | MEDLINE | ID: mdl-34360615

RESUMEN

In contrast to Bacillus subtilis, Streptomyces coelicolor A3(2) contains nine homologues of stress response sigma factor SigB with a major role in differentiation and osmotic stress response. The aim of this study was to further characterize these SigB homologues. We previously established a two-plasmid system to identify promoters recognized by sigma factors and used it to identify promoters recognized by the three SigB homologues, SigF, SigG, and SigH from S. coelicolor A3(2). Here, we used this system to identify 14 promoters recognized by SigB. The promoters were verified in vivo in S. coelicolor A3(2) under osmotic stress conditions in sigB and sigH operon mutants, indicating some cross-recognition of these promoters by these two SigB homologues. This two-plasmid system was used to examine the recognition of all identified SigB-, SigF-, SigG-, and SigH-dependent promoters with all nine SigB homologues. The results confirmed this cross-recognition. Almost all 24 investigated promoters were recognized by two or more SigB homologues and data suggested some distinguishing groups of promoters recognized by these sigma factors. However, analysis of the promoters did not reveal any specific sequence characteristics for these recognition groups. All promoters showed high similarity in the -35 and -10 regions. Immunoblot analysis revealed the presence of SigB under osmotic stress conditions and SigH during morphological differentiation. Together with the phenotypic analysis of sigB and sigH operon mutants in S. coelicolor A3(2), the results suggest a dominant role for SigB in the osmotic stress response and a dual role for SigH in the osmotic stress response and morphological differentiation. These data suggest a complex regulation of the osmotic stress response in relation to morphological differentiation in S. coelicolor A3(2).


Asunto(s)
Proteínas Bacterianas/genética , Regulación Bacteriana de la Expresión Génica , Operón , Regiones Promotoras Genéticas , Factor sigma/genética , Streptomyces coelicolor/genética , Transcripción Genética , Proteínas Bacterianas/metabolismo , Secuencia de Bases , Factor sigma/metabolismo , Streptomyces coelicolor/crecimiento & desarrollo , Streptomyces coelicolor/metabolismo
19.
BMC Genomics ; 22(1): 633, 2021 Aug 31.
Artículo en Inglés | MEDLINE | ID: mdl-34461836

RESUMEN

BACKGROUND: Halogenation is a recurring feature in natural products, especially those from marine organisms. The selectivity with which halogenating enzymes act on their substrates renders halogenases interesting targets for biocatalyst development. Recently, CylC - the first predicted dimetal-carboxylate halogenase to be characterized - was shown to regio- and stereoselectively install a chlorine atom onto an unactivated carbon center during cylindrocyclophane biosynthesis. Homologs of CylC are also found in other characterized cyanobacterial secondary metabolite biosynthetic gene clusters. Due to its novelty in biological catalysis, selectivity and ability to perform C-H activation, this halogenase class is of considerable fundamental and applied interest. The study of CylC-like enzymes will provide insights into substrate scope, mechanism and catalytic partners, and will also enable engineering these biocatalysts for similar or additional C-H activating functions. Still, little is known regarding the diversity and distribution of these enzymes. RESULTS: In this study, we used both genome mining and PCR-based screening to explore the genetic diversity of CylC homologs and their distribution in bacteria. While we found non-cyanobacterial homologs of these enzymes to be rare, we identified a large number of genes encoding CylC-like enzymes in publicly available cyanobacterial genomes and in our in-house culture collection of cyanobacteria. Genes encoding CylC homologs are widely distributed throughout the cyanobacterial tree of life, within biosynthetic gene clusters of distinct architectures (combination of unique gene groups). These enzymes are found in a variety of biosynthetic contexts, which include fatty-acid activating enzymes, type I or type III polyketide synthases, dialkylresorcinol-generating enzymes, monooxygenases or Rieske proteins. Our study also reveals that dimetal-carboxylate halogenases are among the most abundant types of halogenating enzymes in the phylum Cyanobacteria. CONCLUSIONS: Our data show that dimetal-carboxylate halogenases are widely distributed throughout the Cyanobacteria phylum and that BGCs encoding CylC homologs are diverse and mostly uncharacterized. This work will help guide the search for new halogenating biocatalysts and natural product scaffolds.


Asunto(s)
Proteínas Bacterianas , Cianobacterias , Proteínas Bacterianas/genética , Proteínas Bacterianas/metabolismo , Cianobacterias/genética , Cianobacterias/metabolismo , Halogenación , Humanos , Familia de Multigenes , Recurrencia Local de Neoplasia
20.
Appl Microbiol Biotechnol ; 105(18): 6909-6920, 2021 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-34463802

RESUMEN

From the previous transcriptome analysis (Hirasawa et al. Biotechnol J 13:e1700612, 2018), it was found that expression of genes whose expression is regulated by stress-responsive transcriptional regulators was altered during penicillin-induced glutamic acid production in Corynebacterium glutamicum. Therefore, we investigated whether stress treatments, such as copper and iron addition, could induce glutamic acid production in C. glutamicum and found that the addition of copper did induce glutamic acid production in this species. Moreover, we also determined that glutamic acid production levels upon copper addition in a gain-of-function mutant strain of the mechanosensitive channel, NCgl1221, involved in glutamic acid export, were comparable to glutamic acid levels produced upon penicillin addition and biotin limitation in the wild-type strain. Furthermore, disruption of the odhI gene, which encodes a protein responsible for the decreased activity of the 2-oxoglutarate dehydrogenase complex during glutamic acid production, significantly diminished glutamic acid production induced by copper. These results indicate that copper can induce glutamic acid production and this induction requires OdhI like biotin limitation and penicillin addition, but a gain-of-function mutation in the NCgl1221 mechanosensitive channel is necessary for its high-level glutamic acid production. However, a significant increase in odhI transcription was not observed with copper addition in both wild-type and NCgl1221 gain-of-function mutant strains. In addition, disruption of the csoR gene encoding a copper-responsive transcriptional repressor enhanced copper-induced glutamic acid production in the NCgl1221 gain-of-function mutant, indicating that unidentified CsoR-regulated genes may contribute to copper-induced glutamic acid production in C. glutamicum. KEY POINTS: • Copper can induce glutamic acid production by Corynebacterium glutamicum. • Copper-induced glutamic acid production requires OdhI protein. • Copper-induced glutamic acid production requires a gain-of-function mutation in the mechanosensitive channel NCgl1221, which is responsible for the production of glutamic acid.


Asunto(s)
Corynebacterium glutamicum , Proteínas Bacterianas/genética , Cobre , Corynebacterium glutamicum/genética , Ácido Glutámico , Penicilinas
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