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1.
J Antibiot (Tokyo) ; 75(6): 321-332, 2022 Jun.
Article in English | MEDLINE | ID: covidwho-1878523

ABSTRACT

Staphylococcus aureus is one of the most dangerous pathogens commonly associated with high levels of morbidity and mortality. Sortase A is considered as a promising molecular target for the development of antistaphylococcal agents. Using hybrid virtual screening approach and FRET analysis, we have identified five compounds able to decrease the activity of sortase A by more than 50% at the concentration of 200 µM. The most promising compound was 2-(2-amino-3-chloro-benzoylamino)-benzoic acid which was able to inhibit S. aureus sortase A at the IC50 value of 59.7 µM. This compound was selective toward sortase A compared to other four cysteine proteases - cathepsin L, cathepsin B, rhodesain, and the SARS-CoV2 main protease. Microscale thermophoresis experiments confirmed that this compound bound sortase A with KD value of 189 µM. Antibacterial and antibiofilm assays also confirmed high specificity of the hit compound against two standard and three wild-type, S. aureus hospital infection isolates. The effect of the compound on biofilms produced by two S. aureus ATCC strains was also observed suggesting that the compound reduced biofilm formation by changing the biofilm structure and thickness.


Subject(s)
COVID-19 , Staphylococcal Infections , Aminoacyltransferases , Anti-Bacterial Agents/chemistry , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Biofilms , Cysteine Endopeptidases , Humans , Microbial Sensitivity Tests , RNA, Viral/pharmacology , SARS-CoV-2 , Staphylococcus aureus
2.
ACS Chem Biol ; 17(5): 1239-1248, 2022 May 20.
Article in English | MEDLINE | ID: covidwho-1805550

ABSTRACT

Methicillin-resistant Staphylococcus aureus (MRSA) is a major threat to human health, as the US mortality rate outweighs those from HIV, tuberculosis, and viral hepatitis combined. In the wake of the COVID-19 pandemic, antibiotic-resistant bacterial infections acquired during hospital stays have increased. Antibiotic adjuvants are a key strategy to combat these bacteria. We have evaluated several small molecule antibiotic adjuvants that have strong potentiation with ß-lactam antibiotics and are likely inhibiting a master regulatory kinase, Stk1. Here, we investigated how the lead adjuvant (compound 8) exerts its effects in a more comprehensive manner. We hypothesized that the expression levels of key resistance genes would decrease once cotreated with oxacillin and the adjuvant. Furthermore, bioinformatic analyses would reveal biochemical pathways enriched in differentially expressed genes. RNA-seq analysis showed 176 and 233 genes significantly up- and downregulated, respectively, in response to cotreatment. Gene ontology categories and biochemical pathways that were significantly enriched with downregulated genes involved carbohydrate utilization, such as the citrate cycle and the phosphotransferase system. One of the most populated pathways was S. aureus infection. Results from an interaction network constructed with affected gene products supported the hypothesis that Stk1 is a target of compound 8. This study revealed a dramatic impact of our lead adjuvant on the transcriptome that is consistent with a pleiotropic effect due to Stk1 inhibition. These results point to this antibiotic adjuvant having potential broad therapeutic use in combatting MRSA.


Subject(s)
COVID-19 , Methicillin-Resistant Staphylococcus aureus , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/metabolism , Carbazoles/pharmacology , Humans , Methicillin-Resistant Staphylococcus aureus/genetics , Microbial Sensitivity Tests , Pandemics , Staphylococcus aureus , Transcriptome
3.
Biomolecules ; 12(3)2022 02 23.
Article in English | MEDLINE | ID: covidwho-1760346

ABSTRACT

Prokaryotic Argonautes (pAgos) from mesophilic bacteria are attracting increasing attention for their genome editing potential. So far, it has been reported that KmAgo from Kurthia massiliensis can utilize DNA and RNA guide of any sequence to effectively cleave DNA and RNA targets. Here we find that three active pAgos, which have about 50% sequence identity with KmAgo, possess typical DNA-guided DNA target cleavage ability. Among them, RsuAgo from Rummeliibacillus suwonensis is mainly explored for which can cleave both DNA and RNA targets. Interestingly, RsuAgo-mediated RNA target cleavage occurs only with short guide DNAs in a narrow length range (16-20 nt), and mismatches between the guide and target sequence greatly affect the efficiency of RNA target cleavage. RsuAgo-mediated target cleavage shows a preference for a guide strand with a 5'-terminal A residue. Furthermore, we have found that RsuAgo can cleave double-stranded DNA in a low-salt buffer at 37 °C. These properties of RsuAgo provide a new tool for DNA and RNA manipulation at moderate temperatures.


Subject(s)
Argonaute Proteins , Bacterial Proteins , Argonaute Proteins/genetics , Bacteria/metabolism , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , DNA/chemistry , Endonucleases , Planococcaceae , RNA
4.
Cell Rep ; 38(8): 110414, 2022 02 22.
Article in English | MEDLINE | ID: covidwho-1700507

ABSTRACT

Inflammasome activation exacerbates infectious disease caused by pathogens such as Listeria monocytogenes, Staphylococcus aureus, and severe acute respiratory syndrome coronavirus 2. Although these pathogens activate host inflammasomes to regulate pathogen expansion, the mechanisms by which pathogen toxins contribute to inflammasome activation remain poorly understood. Here we show that activation of inflammasomes by Listeria infection is promoted by amino acid residue T223 of listeriolysin O (LLO) independently of its pore-forming activity. LLO T223 is critical for phosphorylation of the inflammasome adaptor ASC at amino acid residue Y144 through Lyn-Syk signaling, which is essential for ASC oligomerization. Notably, a Listeria mutant expressing LLO T223A is impaired in inducing ASC phosphorylation and inflammasome activation. Furthermore, the virulence of LLO T223A mutant is markedly attenuated in vivo due to impaired ability to activate the inflammasome. Our results reveal a function of a pathogen toxin that exacerbates infection by promoting phosphorylation of ASC.


Subject(s)
Bacterial Proteins/metabolism , Bacterial Toxins/metabolism , CARD Signaling Adaptor Proteins/metabolism , Heat-Shock Proteins/metabolism , Hemolysin Proteins/metabolism , Inflammasomes/metabolism , Listeria monocytogenes/pathogenicity , Signal Transduction , Amino Acid Sequence , Animals , Bacterial Proteins/genetics , Bacterial Toxins/chemistry , Bacterial Toxins/genetics , CARD Signaling Adaptor Proteins/chemistry , CARD Signaling Adaptor Proteins/deficiency , CARD Signaling Adaptor Proteins/genetics , Gene Editing , Heat-Shock Proteins/chemistry , Heat-Shock Proteins/genetics , Hemolysin Proteins/chemistry , Hemolysin Proteins/genetics , Interleukin-18/metabolism , Listeria monocytogenes/metabolism , Macrophages, Peritoneal/cytology , Macrophages, Peritoneal/metabolism , Macrophages, Peritoneal/microbiology , Mice , Mice, Inbred C57BL , Mice, Knockout , Mutagenesis, Site-Directed , Phosphorylation , Syk Kinase/genetics , Syk Kinase/metabolism , Virulence , src-Family Kinases/genetics , src-Family Kinases/metabolism
5.
Cells ; 11(3)2022 01 27.
Article in English | MEDLINE | ID: covidwho-1662647

ABSTRACT

In this contribution, we report on the possibility that cryptococcal protease(s) could activate the SARS-CoV-2 spike (S) protein. The S protein is documented to have a unique four-amino-acid sequence (underlined, SPRRAR↓S) at the interface between the S1 and S2 sites, that serves as a cleavage site for the human protease, furin. We compared the biochemical efficiency of cryptococcal protease(s) and furin to mediate the proteolytic cleavage of the S1/S2 site in a fluorogenic peptide. We show that cryptococcal protease(s) processes this site in a manner comparable to the efficiency of furin (p > 0.581). We conclude the paper by discussing the impact of these findings in the context of a SARS-CoV-2 disease manifesting while there is an underlying cryptococcal infection.


Subject(s)
Aspartic Acid Proteases/metabolism , Bacterial Proteins/metabolism , Cryptococcus neoformans/enzymology , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/metabolism , Amino Acid Sequence , Aspartic Acid Proteases/genetics , Bacterial Proteins/genetics , Binding Sites , COVID-19/epidemiology , COVID-19/prevention & control , COVID-19/virology , Cryptococcus neoformans/genetics , Fluorescent Dyes/chemistry , Furin/genetics , Furin/metabolism , Humans , Pandemics , Peptides/chemistry , Peptides/metabolism , Proteolysis , SARS-CoV-2/physiology
6.
Front Immunol ; 12: 714027, 2021.
Article in English | MEDLINE | ID: covidwho-1581346

ABSTRACT

In the coronavirus disease 2019 (COVID-19) health crisis, one major challenge is to identify the susceptibility factors of severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) in order to adapt the recommendations for populations, as well as to reduce the risk of COVID-19 development in the most vulnerable people, especially patients with chronic respiratory diseases such as cystic fibrosis (CF). Airway epithelial cells (AECs) play a critical role in the modulation of both immune responses and COVID-19 severity. SARS-CoV-2 infects the airway through the receptor angiotensin-converting enzyme 2, and a host protease, transmembrane serine protease 2 (TMPRSS2), plays a major role in SARS-CoV-2 infectivity. Here, we show that Pseudomonas aeruginosa increases TMPRSS2 expression, notably in primary AECs with deficiency of the ion channel CF transmembrane conductance regulator (CFTR). Further, we show that the main component of P. aeruginosa flagella, the protein flagellin, increases TMPRSS2 expression in primary AECs and Calu-3 cells, through activation of Toll-like receptor-5 and p38 MAPK. This increase is particularly seen in Calu-3 cells deficient for CFTR and is associated with an intracellular increased level of SARS-CoV-2 infection, however, with no effect on the amount of virus particles released. Considering the urgency of the COVID-19 health crisis, this result may be of clinical significance for CF patients, who are frequently infected with and colonized by P. aeruginosa during the course of CF and might develop COVID-19.


Subject(s)
Cystic Fibrosis , Flagellin/metabolism , Pseudomonas Infections/complications , Respiratory Mucosa/virology , SARS-CoV-2/pathogenicity , Serine Endopeptidases/metabolism , Bacterial Proteins/metabolism , COVID-19/complications , Cells, Cultured , Humans , Pseudomonas aeruginosa , Respiratory Mucosa/metabolism
7.
RNA ; 28(2): 227-238, 2022 02.
Article in English | MEDLINE | ID: covidwho-1533393

ABSTRACT

The Bacillus subtilis genome is predicted to encode numerous ribonucleases, including four 3' exoribonucleases that have been characterized to some extent. A strain containing gene knockouts of all four known 3' exoribonucleases is viable, suggesting that one or more additional RNases remain to be discovered. A protein extract from the quadruple RNase mutant strain was fractionated and RNase activity was followed, resulting in the identification of an enzyme activity catalyzed by the YloC protein. YloC is an endoribonuclease and is a member of the highly conserved "YicC family" of proteins that is widespread in bacteria. YloC is a metal-dependent enzyme that catalyzes the cleavage of single-stranded RNA, preferentially at U residues, and exists in an oligomeric form, most likely a hexamer. As such, YloC shares some characteristics with the SARS-CoV Nsp15 endoribonuclease. While the in vivo function of YloC in B. subtilis is yet to be determined, YloC was found to act similarly to YicC in an Escherichia coli in vivo assay that assesses decay of the small RNA, RyhB. Thus, YloC may play a role in small RNA regulation.


Subject(s)
Bacillus subtilis/genetics , Endoribonucleases/genetics , Endoribonucleases/metabolism , Bacillus subtilis/enzymology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Endoribonucleases/chemistry , Escherichia coli/genetics , Escherichia coli/metabolism , Escherichia coli Proteins/metabolism , Gene Expression Regulation, Bacterial , Microorganisms, Genetically-Modified , Mutation , RNA Stability , RNA, Bacterial/chemistry , RNA, Bacterial/metabolism , Ribonucleases/genetics , Ribonucleases/metabolism , Substrate Specificity , Viral Nonstructural Proteins/metabolism
8.
Eur J Clin Microbiol Infect Dis ; 40(11): 2295-2303, 2021 Nov.
Article in English | MEDLINE | ID: covidwho-1479485

ABSTRACT

The aim of this study is to present the first nationwide microbiological and epidemiological study of invasive group A Streptococcus (iGAS) disease in Spain. One thousand eight hundred ninety-three iGAS isolates were analyzed over 2007-2019. emm typing was performed by sequencing the gene's variable 5' end, exotoxin genes were identified by PCR, and antimicrobial susceptibility explored via the E test and disk diffusion. Five hundred twenty-three isolates were associated with sepsis, 292 with cellulitis, 232 with scarlet fever, 153 with pneumonia, 141 with streptococcal toxic shock syndrome, and 94 with necrotizing fasciitis. The most prevalent emm types were emm1 (449/1893 isolates), emm89 (210/1893), emm3 (208/1893), emm4 (150/1893), emm12 (112/1893) emm6 (107/1893), emm87 (89/1893), emm28 (88/1893), emm75 (78/1893), emm77 (78/1893), emm11 (58/1893), and emm22 (35/1893). emm1, emm3, emm4, and emm6 were the predominant types affecting children (mostly respiratory infections), while emm11, emm77, and emm89 prevailed in the elderly (mostly skin infections). Each emm type was associated with one or more exotoxin gene (spe, sme, and ssa) profiles. speA was detected in 660 isolates, speB in 1829, speC in 1014, speF in 1826, speG in 1651, speJ in 716, speH in 331, smeZ in 720, and ssa in 512. Isolates with speA were associated with the most severe infections. Penicillin susceptibility was universal. Two hundred twenty-four isolates were resistant to tetracycline, 169 to erythromycin, and 81 to clindamycin. Tetracycline, erythromycin, and clindamycin resistance rates declined over the study period. The above information could serve as the basis for continued surveillance efforts designed to control disease cause by this bacterium.


Subject(s)
Streptococcal Infections/microbiology , Streptococcus pyogenes/isolation & purification , Adolescent , Adult , Aged , Aged, 80 and over , Anti-Bacterial Agents/pharmacology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , Carrier Proteins/genetics , Carrier Proteins/metabolism , Child , Child, Preschool , Erythromycin/pharmacology , Exotoxins/genetics , Exotoxins/metabolism , Female , Humans , Infant , Male , Membrane Proteins/genetics , Membrane Proteins/metabolism , Microbial Sensitivity Tests , Middle Aged , Penicillins/pharmacology , Spain/epidemiology , Streptococcal Infections/epidemiology , Streptococcus pyogenes/classification , Streptococcus pyogenes/drug effects , Streptococcus pyogenes/genetics , Young Adult
9.
FEBS Open Bio ; 11(12): 3237-3252, 2021 12.
Article in English | MEDLINE | ID: covidwho-1473791

ABSTRACT

Autophagy is an intracellular degradation and recycling process that can also remove pathogenic intracellular bacteria and viruses from within cells (referred to as xenophagy) and activate the adaptive immune responses. But autophagy-especially Atg proteins including Atg8 family members-can also have proviral and probacterial effects. In this review, we summarize known interactions of bacterial, parasitic, and viral proteins with Atg8 family proteins and the outcome of these interactions on pathogen replication, autophagy, or mitophagy. We discuss the value of prediction software and the research methodology in the study of pathogen protein-Atg8 family protein interactions, with selected examples of potential LC3-interacting region motif-containing SARS-CoV-2 proteins.


Subject(s)
Bacterial Proteins/metabolism , Fungal Proteins/metabolism , Microtubule-Associated Proteins/metabolism , SARS-CoV-2/metabolism , Viral Proteins/metabolism , Autophagy , Autophagy-Related Protein 8 Family/metabolism , Humans , Mitophagy , Protein Interaction Maps , Software
10.
Front Immunol ; 12: 757691, 2021.
Article in English | MEDLINE | ID: covidwho-1463478

ABSTRACT

The increase in confirmed COVID-19 cases and SARS-CoV-2 variants calls for the development of safe and broad cross-protective vaccines. The RBD of the spike protein was considered to be a safe and effective candidate antigen. However, the low immunogenicity limited its application in vaccine development. Herein, we designed and obtained an RBD heptamer (mHla-RBD) based on a carrier protein-aided assembly strategy. The molecular weight of mHla-RBD is up to 450 kDa, approximately 10 times higher than that of the RBD monomer. When formulated with alum adjuvant, mHla-RBD immunization significantly increased the immunogenicity of RBD, as indicated by increased titers of RBD-specific antibodies, neutralizing antibodies, Th2 cellular immune response, and pseudovirus neutralization activity, when compared to RBD monomer. Furthermore, we confirmed that RBD-specific antibodies predominantly target conformational epitopes, which was approximately 200 times that targeting linear epitopes. Finally, a pseudovirus neutralization assay revealed that neutralizing antibodies induced by mHla-RBD against different SARS-CoV-2 variants were comparable to those against the wild-type virus and showed broad-spectrum neutralizing activity toward different SARS-CoV-2 variants. Our results demonstrated that mHla-RBD is a promising candidate antigen for development of SARS-CoV-2 vaccines and the mHla could serve as a universal carrier protein for antigen design.


Subject(s)
Bacterial Proteins/metabolism , COVID-19 Vaccines/immunology , COVID-19/immunology , Carrier Proteins/metabolism , Hemolysin Proteins/metabolism , SARS-CoV-2/physiology , Spike Glycoprotein, Coronavirus/metabolism , Th2 Cells/immunology , Animals , Antibodies, Neutralizing/metabolism , Antibodies, Viral/metabolism , Broadly Neutralizing Antibodies/metabolism , Cell Line , Escherichia coli Proteins , Humans , Lymphocyte Activation , Mice , Mice, Inbred BALB C , Protein Domains/genetics , Spike Glycoprotein, Coronavirus/genetics , Spike Glycoprotein, Coronavirus/immunology
11.
Molecules ; 26(19)2021 Oct 02.
Article in English | MEDLINE | ID: covidwho-1463766

ABSTRACT

Commensal bacterium Clostridium paraputrificum J4 produces several extracellular chitinolytic enzymes including a 62 kDa chitinase Chit62J4 active toward 4-nitrophenyl N,N'-diacetyl-ß-d-chitobioside (pNGG). We characterized the crude enzyme from bacterial culture fluid, recombinant enzyme rChit62J4, and its catalytic domain rChit62J4cat. This major chitinase, securing nutrition of the bacterium in the human intestinal tract when supplied with chitin, has a pH optimum of 5.5 and processes pNGG with Km = 0.24 mM and kcat = 30.0 s-1. Sequence comparison of the amino acid sequence of Chit62J4, determined during bacterial genome sequencing, characterizes the enzyme as a family 18 glycosyl hydrolase with a four-domain structure. The catalytic domain has the typical TIM barrel structure and the accessory domains-2x Fn3/Big3 and a carbohydrate binding module-that likely supports enzyme activity on chitin fibers. The catalytic domain is highly homologous to a single-domain chitinase of Bacillus cereus NCTU2. However, the catalytic profiles significantly differ between the two enzymes despite almost identical catalytic sites. The shift of pI and pH optimum of the commensal enzyme toward acidic values compared to the soil bacterium is the likely environmental adaptation that provides C. paraputrificum J4 a competitive advantage over other commensal bacteria.


Subject(s)
Bacterial Proteins/metabolism , Chitin/metabolism , Chitinases/metabolism , Clostridium/metabolism , Bacterial Proteins/genetics , Catalytic Domain , Chitinases/chemistry , Chitinases/genetics , Clostridium/growth & development , Clostridium/isolation & purification , Gastrointestinal Microbiome , Humans , Hydrogen-Ion Concentration , Recombinant Proteins/genetics , Recombinant Proteins/metabolism
12.
Carbohydr Polym ; 273: 118605, 2021 Dec 01.
Article in English | MEDLINE | ID: covidwho-1370153

ABSTRACT

Advanced biomaterials provide an interesting and versatile platform to implement new and more effective strategies to fight bacterial infections. Chitosan is one of these biopolymers and possesses relevant features for biomedical applications. Here we synthesized nanoparticles of chitosan derivatized with diethylaminoethyl groups (ChiDENPs) to emulate the choline residues in the pneumococcal cell wall and act as ligands for choline-binding proteins (CBPs). Firstly, we assessed the ability of diethylaminoethyl (DEAE) to sequester the CBPs present in the bacterial surface, thus promoting chain formation. Secondly, the CBP-binding ability of ChiDENPs was purposed to encapsulate a bio-active molecule, the antimicrobial enzyme Cpl-711 (ChiDENPs-711), with improved stability over non-derivatized chitosan. The enzyme-loaded system released more than 90% of the active enzybiotic in ≈ 2 h, above the usual in vivo half-life of this kind of enzymes. Therefore, ChiDENPs provide a promising platform for the controlled release of CBP-enzybiotics in biological contexts.


Subject(s)
Anti-Bacterial Agents/pharmacology , Biomimetic Materials/chemistry , Chitosan/analogs & derivatives , Drug Carriers/chemistry , Endopeptidases/pharmacology , Nanoparticles/chemistry , A549 Cells , Anti-Bacterial Agents/chemistry , Bacterial Proteins/metabolism , Biomimetic Materials/metabolism , Chitosan/chemistry , Chitosan/metabolism , Drug Carriers/metabolism , Drug Liberation , Endopeptidases/chemistry , Humans , Nanoparticles/metabolism , Streptococcus pneumoniae/drug effects
13.
Int J Mol Sci ; 22(17)2021 Aug 26.
Article in English | MEDLINE | ID: covidwho-1374425

ABSTRACT

Bifidobacteria are some of the major agents that shaped the immune system of many members of the animal kingdom during their evolution. Over recent years, the question of concrete mechanisms underlying the immunomodulatory properties of bifidobacteria has been addressed in both animal and human studies. A possible candidate for this role has been discovered recently. The PFNA cluster, consisting of five core genes, pkb2, fn3, aaa-atp, duf58, tgm, has been found in all gut-dwelling autochthonous bifidobacterial species of humans. The sensory region of the species-specific serine-threonine protein kinase (PKB2), the transmembrane region of the microbial transglutaminase (TGM), and the type-III fibronectin domain-containing protein (FN3) encoded by the I gene imply that the PFNA cluster might be implicated in the interaction between bacteria and the host immune system. Moreover, the FN3 protein encoded by one of the genes making up the PFNA cluster, contains domains and motifs of cytokine receptors capable of selectively binding TNF-α. The PFNA cluster could play an important role for sensing signals of the immune system. Among the practical implications of this finding is the creation of anti-inflammatory drugs aimed at alleviating cytokine storms, one of the dire consequences resulting from SARS-CoV-2 infection.


Subject(s)
Bacterial Proteins/genetics , Bifidobacterium/physiology , COVID-19/therapy , /genetics , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , COVID-19/immunology , COVID-19/virology , Cytokine Release Syndrome/immunology , Cytokine Release Syndrome/prevention & control , Cytokines/chemistry , Cytokines/metabolism , Humans , Immune System , Operon/genetics , /metabolism , SARS-CoV-2/isolation & purification
14.
Biosensors (Basel) ; 11(9)2021 Aug 28.
Article in English | MEDLINE | ID: covidwho-1374295

ABSTRACT

The outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease-19 (COVID-19), has severely influenced public health and economics. For the detection of SARS-CoV-2, clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR associated protein (Cas)-based assays have been emerged because of their simplicity, sensitivity, specificity, and wide applicability. Herein, we have developed a CRISPR-Cas12-based assay for the detection of SARS-CoV-2. In the assay, the target amplicons are produced by isothermal reverse transcription recombinase polymerase amplification (RT-RPA) and recognized by a CRISPR-Cas12a/guide RNA (gRNA) complex that is coupled with the collateral cleavage activity of fluorophore-tagged probes, allowing either a fluorescent measurement or naked-eye detection on a lateral flow paper strip. This assay enables the sensitive detection of SARS-CoV-2 at a low concentration of 10 copies per sample. Moreover, the reliability of the method is verified by using nasal swabs and sputum of COVID-19 patients. We also proved that the current assay can be applied to other viruses, such as Middle East respiratory syndrome coronavirus (MERS-CoV) and severe acute respiratory syndrome coronavirus (SARS-CoV), with no major changes to the basic scheme of testing. It is anticipated that the CRISPR-Cas12-based assay has the potential to serve as a point-of-care testing (POCT) tool for a wide range of infectious viruses.


Subject(s)
Bacterial Proteins/metabolism , CRISPR-Associated Proteins/metabolism , Endodeoxyribonucleases/metabolism , Middle East Respiratory Syndrome Coronavirus/isolation & purification , SARS Virus/isolation & purification , SARS-CoV-2/isolation & purification , Virus Diseases/diagnosis , CRISPR-Cas Systems , Fluorescent Dyes/chemistry , Humans , Middle East Respiratory Syndrome Coronavirus/genetics , Nose/virology , Point-of-Care Testing , RNA, Guide/chemistry , RNA, Guide/genetics , Reverse Transcriptase Polymerase Chain Reaction , SARS Virus/genetics , SARS-CoV-2/genetics , Sensitivity and Specificity , Sputum/virology
15.
ACS Appl Bio Mater ; 4(7): 5471-5484, 2021 07 19.
Article in English | MEDLINE | ID: covidwho-1337090

ABSTRACT

Centers for Disease Control and Prevention (CDC) warns the use of one-way valves or vents in face masks for potential threat of spreading COVID-19 through expelled respiratory droplets. Here, we have developed a nanoceutical cotton fabric duly sensitized with non-toxic zinc oxide nanomaterial for potential use as a membrane filter in the one-way valve for the ease of breathing without the threat of COVID-19 spreading. A detailed computational study revealed that zinc oxide nanoflowers (ZnO NFs) with almost two-dimensional petals trap SARS-CoV-2 spike proteins, responsible to attach to ACE-2 receptors in human lung epithelial cells. The study also confirmed significant denaturation of the spike proteins on the ZnO surface, revealing removal of the virus upon efficient trapping. Following the computational study, we have synthesized ZnO NF on a cotton matrix using a hydrothermal-assisted strategy. Electron-microscopic, steady-state, and picosecond-resolved spectroscopic studies confirm attachment of ZnO NF to the cotton (i.e., cellulose) matrix at the atomic level to develop the nanoceutical fabric. A detailed antimicrobial assay using Pseudomonas aeruginosa bacteria (model SARS-CoV-2 mimic) reveals excellent antimicrobial efficiency of the developed nanoceutical fabric. To our understanding, the nanoceutical fabric used in the one-way valve of a face mask would be the choice to assure breathing comfort along with source control of COVID-19 infection. The developed nanosensitized cloth can also be used as an antibacterial/anti CoV-2 washable dress material in general.


Subject(s)
Anti-Infective Agents/chemistry , COVID-19/prevention & control , Nanostructures/chemistry , Anti-Infective Agents/metabolism , Anti-Infective Agents/pharmacology , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , COVID-19/virology , Cotton Fiber/analysis , Humans , Masks , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/metabolism , Recycling , SARS-CoV-2/drug effects , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism , Zinc Oxide/chemistry
16.
ACS Appl Bio Mater ; 4(7): 5485-5493, 2021 07 19.
Article in English | MEDLINE | ID: covidwho-1327183

ABSTRACT

Attachment of microbial bodies including the corona virus on the surface of personal protective equipment (PPE) is found to be potential threat of spreading infection. Here, we report the development of a triboelectroceutical fabric (TECF) consisting of commonly available materials, namely, nylon and silicone rubber (SR), for the fabrication of protective gloves on the nitrile platform as model wearable PPE. A small triboelectric device (2 cm × 2 cm) consisting of SR and nylon on nitrile can generate more than 20 V transient or 41 µW output power, which is capable of charging a capacitor up to 65 V in only ∼50 s. The importance of the present work relies on the TECF-led antimicrobial activity through the generation of an electric current in saline water. The fabrication of TECF-based functional prototype gloves can generate hypochlorite ions through the formation of electrolyzed water upon rubbing them with saline water. Further, computational modelling has been employed to reveal the optimum structure and mechanistic pathway of antimicrobial hypochlorite generation. Detailed antimicrobial assays have been performed to establish effectiveness of such TECF-based gloves to reduce the risk from life-threatening pathogen spreading. The present work provides the rationale to consider the studied TECF, or other materials with comparable properties, as a material of choice for the development of self-sanitizing PPE in the fight against microbial infections including COVID-19.


Subject(s)
Anti-Infective Agents/chemistry , Electricity , Personal Protective Equipment , Anti-Infective Agents/metabolism , Anti-Infective Agents/pharmacology , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Biomimetic Materials/chemistry , Biomimetic Materials/pharmacology , COVID-19/pathology , COVID-19/prevention & control , COVID-19/virology , Humans , Nylons/chemistry , Personal Protective Equipment/microbiology , Personal Protective Equipment/virology , Pseudomonas aeruginosa/drug effects , Pseudomonas aeruginosa/metabolism , Recycling , SARS-CoV-2/drug effects , SARS-CoV-2/isolation & purification , SARS-CoV-2/metabolism , Silicone Elastomers/chemistry , Spike Glycoprotein, Coronavirus/chemistry , Spike Glycoprotein, Coronavirus/metabolism
17.
Microbiology (Reading) ; 167(3)2021 03.
Article in English | MEDLINE | ID: covidwho-1288221

ABSTRACT

Biofilm formation in the human intestinal pathogen Vibrio cholerae is in part regulated by norspermidine, spermidine and spermine. V. cholerae senses these polyamines through a signalling pathway consisting of the periplasmic protein, NspS, and the integral membrane c-di-GMP phosphodiesterase MbaA. NspS and MbaA belong to a proposed class of novel signalling systems composed of periplasmic ligand-binding proteins and membrane-bound c-di-GMP phosphodiesterases containing both GGDEF and EAL domains. In this signal transduction pathway, NspS is hypothesized to interact with MbaA in the periplasm to regulate its phosphodiesterase activity. Polyamine binding to NspS likely alters this interaction, leading to the activation or inhibition of biofilm formation depending on the polyamine. The purpose of this study was to determine the amino acids important for NspS function. We performed random mutagenesis of the nspS gene, identified mutant clones deficient in biofilm formation, determined their responsiveness to norspermidine and mapped the location of these residues onto NspS homology models. Single mutants clustered on two lobes of the NspS model, but the majority were found on a single lobe that appeared to be more mobile upon norspermidine binding. We also identified residues in the putative ligand-binding site that may be important for norspermidine binding and interactions with MbaA. Ultimately, our results provide new insights into this novel signalling pathway in V. cholerae and highlight differences between periplasmic binding proteins involved in transport versus signal transduction.


Subject(s)
Bacterial Proteins/genetics , Biofilms , Vibrio cholerae/genetics , Amino Acid Sequence , Bacterial Proteins/chemistry , Bacterial Proteins/metabolism , Gene Expression Regulation, Bacterial , Mutagenesis , Periplasm/genetics , Periplasm/metabolism , Protein Domains , Sequence Alignment , Signal Transduction , Vibrio cholerae/chemistry , Vibrio cholerae/physiology
18.
Sci Rep ; 11(1): 12410, 2021 06 14.
Article in English | MEDLINE | ID: covidwho-1268005

ABSTRACT

In situ generation of antibacterial and antiviral agents by harnessing the catalytic activity of enzymes on surfaces provides an effective eco-friendly approach for disinfection. The perhydrolase (AcT) from Mycobacterium smegmatis catalyzes the perhydrolysis of acetate esters to generate the potent disinfectant, peracetic acid (PAA). In the presence of AcT and its two substrates, propylene glycol diacetate and H2O2, sufficient and continuous PAA is generated over an extended time to kill a wide range of bacteria with the enzyme dissolved in aqueous buffer. For extended self-disinfection, however, active and stable AcT bound onto or incorporated into a surface coating is necessary. In the current study, an active, stable and reusable AcT-based coating was developed by incorporating AcT into a polydopamine (PDA) matrix in a single step, thereby forming a biocatalytic composite onto a variety of surfaces. The resulting AcT-PDA composite coatings on glass, metal and epoxy surfaces yielded up to 7-log reduction of Gram-positive and Gram-negative bacteria when in contact with the biocatalytic coating. This composite coating also possessed potent antiviral activity, and dramatically reduced the infectivity of a SARS-CoV-2 pseudovirus within minutes. The single-step approach enables rapid and facile fabrication of enzyme-based disinfectant composite coatings with high activity and stability, which enables reuse following surface washing. As a result, this enzyme-polymer composite technique may serve as a general strategy for preparing antibacterial and antiviral surfaces for applications in health care and common infrastructure safety, such as in schools, the workplace, transportation, etc.


Subject(s)
Anti-Bacterial Agents/chemistry , Antiviral Agents/chemistry , Bacterial Proteins/chemistry , Hydrolases/chemistry , Indoles/chemistry , Polymers/chemistry , Anti-Bacterial Agents/metabolism , Anti-Bacterial Agents/pharmacology , Antiviral Agents/metabolism , Antiviral Agents/pharmacology , Bacterial Proteins/genetics , Bacterial Proteins/metabolism , COVID-19/pathology , COVID-19/virology , Coated Materials, Biocompatible/chemistry , Coated Materials, Biocompatible/metabolism , Coated Materials, Biocompatible/pharmacology , Drug Stability , Gram-Negative Bacteria/drug effects , Gram-Positive Bacteria/drug effects , Humans , Hydrolases/genetics , Hydrolases/metabolism , Kinetics , Mycobacterium smegmatis/enzymology , Peracetic Acid/metabolism , Recombinant Proteins/biosynthesis , Recombinant Proteins/chemistry , Recombinant Proteins/isolation & purification , SARS-CoV-2/drug effects
19.
Appl Environ Microbiol ; 87(11)2021 05 11.
Article in English | MEDLINE | ID: covidwho-1225696

ABSTRACT

The widely prescribed pharmaceutical metformin and its main metabolite, guanylurea, are currently two of the most common contaminants in surface and wastewater. Guanylurea often accumulates and is poorly, if at all, biodegraded in wastewater treatment plants. This study describes Pseudomonas mendocina strain GU, isolated from a municipal wastewater treatment plant, using guanylurea as its sole nitrogen source. The genome was sequenced with 36-fold coverage and mined to identify guanylurea degradation genes. The gene encoding the enzyme initiating guanylurea metabolism was expressed, and the enzyme was purified and characterized. Guanylurea hydrolase, a newly described enzyme, was shown to transform guanylurea to one equivalent (each) of ammonia and guanidine. Guanidine also supports growth as a sole nitrogen source. Cell yields from growth on limiting concentrations of guanylurea revealed that metabolism releases all four nitrogen atoms. Genes encoding complete metabolic transformation were identified bioinformatically, defining the pathway as follows: guanylurea to guanidine to carboxyguanidine to allophanate to ammonia and carbon dioxide. The first enzyme, guanylurea hydrolase, is a member of the isochorismatase-like hydrolase protein family, which includes biuret hydrolase and triuret hydrolase. Although homologs, the three enzymes show distinct substrate specificities. Pairwise sequence comparisons and the use of sequence similarity networks allowed fine structure discrimination between the three homologous enzymes and provided insights into the evolutionary origins of guanylurea hydrolase.IMPORTANCE Metformin is a pharmaceutical most prescribed for type 2 diabetes and is now being examined for potential benefits to COVID-19 patients. People taking the drug pass it largely unchanged, and it subsequently enters wastewater treatment plants. Metformin has been known to be metabolized to guanylurea. The levels of guanylurea often exceed that of metformin, leading to the former being considered a "dead-end" metabolite. Metformin and guanylurea are water pollutants of emerging concern, as they persist to reach nontarget aquatic life and humans, the latter if it remains in treated water. The present study has identified a Pseudomonas mendocina strain that completely degrades guanylurea. The genome was sequenced, and the genes involved in guanylurea metabolism were identified in three widely separated genomic regions. This knowledge advances the idea that guanylurea is not a dead-end product and will allow for bioinformatic identification of the relevant genes in wastewater treatment plant microbiomes and other environments subjected to metagenomic sequencing.


Subject(s)
Bacterial Proteins/metabolism , Guanidine/analogs & derivatives , Hydrolases/metabolism , Metabolic Networks and Pathways , Metformin/metabolism , Urea/analogs & derivatives , Water Pollutants, Chemical/metabolism , Ammonia/metabolism , Bacterial Proteins/genetics , Biodegradation, Environmental , Biomineralization , Genome, Bacterial/genetics , Guanidine/metabolism , Hydrolases/genetics , Multigene Family , Pseudomonas mendocina/genetics , Pseudomonas mendocina/isolation & purification , Pseudomonas mendocina/metabolism , Substrate Specificity , Urea/metabolism , Waste Water/microbiology
20.
Future Microbiol ; 16: 487-507, 2021 05.
Article in English | MEDLINE | ID: covidwho-1219499

ABSTRACT

Aim: The confirmation of lipolytic activity and role of Rv1900c in the Mycobacterium physiology Methods: rv1900c/N-terminus domain (rv1900NT) were cloned in pET28a/Escherichia coli, purified by affinity chromatography and characterized. Results: A zone of clearance on tributyrin-agar and activity with pNP-decanoate confirmed the lipolytic activity of Rv1900c. The Rv1900NT demonstrated higher enzyme specific activity, Vmax and kcat, but Rv1900c was more thermostable. The lipolytic activity of Rv1900c decreased in presence of ATP. Mycobacterium smegmatis expressed rv1900c/rv1900NT-altered colony morphology, growth, cell surface properties and survival under stress conditions. The effect was more prominent with Rv1900NT as compared with Rv1900c. Conclusion: The study confirmed the lipolytic activity of Rv1900c and suggested its regulation by the adenylate cyclase domain and role in the intracellular survival of bacteria.


Lay abstract Tuberculosis (TB) remains the top contagious/infectious killer in the world. It is caused by the bacteria Mycobacterium tuberculosis. The bacteria resides/replicates in the immune cell that normally has to eradicate infectious microorganisms. Though the treatment of TB is available, the emergence of drug-resistant bacteria is of major concern. The treatment of drug-resistant TB has been reported to be more difficult due to lengthy and complex treatment regimens. Therefore, there is an urgent need for new and better drugs to treat TB/drug-resistant TB. For this purpose understanding the role of each protein in the physiology of mycobacteria is required. Lipids play a critical role in the intracellular survival of this pathogen in the host. Our study demonstrated that LipJ supported the intracellular survival of bacteria. Therefore, it could be a potential drug target.


Subject(s)
Adenylyl Cyclases/metabolism , Bacterial Proteins/metabolism , Lipase/metabolism , Adenosine Triphosphate/metabolism , Adenylyl Cyclases/chemistry , Adenylyl Cyclases/genetics , Adenylyl Cyclases/isolation & purification , Amino Acid Sequence , Bacterial Proteins/chemistry , Bacterial Proteins/genetics , Bacterial Proteins/isolation & purification , Biofilms/growth & development , Catalytic Domain , Cell Wall/physiology , Cloning, Molecular , Enzyme Stability , Hydrogen-Ion Concentration , Lipase/chemistry , Lipase/genetics , Lipase/isolation & purification , Lipolysis , Mycobacterium smegmatis/genetics , Mycobacterium smegmatis/physiology , Mycobacterium tuberculosis/enzymology , Mycobacterium tuberculosis/genetics , Recombinant Proteins/chemistry , Recombinant Proteins/genetics , Recombinant Proteins/isolation & purification , Recombinant Proteins/metabolism , Stress, Physiological , Temperature
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