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Science (New York, N.Y.) Oct 2018Bacterial CRISPR-Cas systems protect their host from bacteriophages and other mobile genetic elements. Mobile elements, in turn, encode various anti-CRISPR (Acr)...
Bacterial CRISPR-Cas systems protect their host from bacteriophages and other mobile genetic elements. Mobile elements, in turn, encode various anti-CRISPR (Acr) proteins to inhibit the immune function of CRISPR-Cas. To date, Acr proteins have been discovered for type I (subtypes I-D, I-E, and I-F) and type II (II-A and II-C) but not other CRISPR systems. Here, we report the discovery of 12 genes, including inhibitors of type V-A and I-C CRISPR systems. AcrVA1 inhibits a broad spectrum of Cas12a (Cpf1) orthologs-including MbCas12a, Mb3Cas12a, AsCas12a, and LbCas12a-when assayed in human cells. The genes reported here provide useful biotechnological tools and mark the discovery of loci in many bacteria and phages.
Topics: Bacterial Proteins; CRISPR-Cas Systems; Cell Line; Computational Biology; Endonucleases; Gene Editing; Humans; Moraxella; Pseudomonas
PubMed: 30190308
DOI: 10.1126/science.aau5174 -
Journal of Cell Science May 2020As an alternative and complementary approach to Cas9-based genome editing, Cas12a has not been widely used in mammalian cells largely due to its strict requirement for...
As an alternative and complementary approach to Cas9-based genome editing, Cas12a has not been widely used in mammalian cells largely due to its strict requirement for the TTTV protospacer adjacent motif (PAM) sequence. Here, we report that Mb3Cas12a ( AAX11_00205) can efficiently edit the mouse genome based on the TTV PAM sequence with minimal numbers of large on-target deletions or insertions. When TTTV PAM sequence-targeting CRISPR (cr)RNAs of 23 nt spacers are used, >70% of the founders obtained are edited. Moreover, the use of Mb3Cas12a tagged to monomeric streptavidin (mSA) in conjunction with biotinylated DNA donor template leads to high knock-in efficiency in two-cell mouse embryos, with 40% of founders obtained containing the desired knock-in sequences.
Topics: Animals; CRISPR-Cas Systems; Clustered Regularly Interspaced Short Palindromic Repeats; Gene Editing; Mice; Moraxella; RNA
PubMed: 32393674
DOI: 10.1242/jcs.240705 -
Clinical Microbiology Reviews Oct 1990Branhamella catarrhalis was formerly regarded as a common, essentially harmless inhabitant of the pharynx. This misapprehension was caused, in part, by confusion with... (Review)
Review
Branhamella catarrhalis was formerly regarded as a common, essentially harmless inhabitant of the pharynx. This misapprehension was caused, in part, by confusion with another pharyngeal resident, Neisseria cinerea. The two organisms can now be differentiated by the positive reactions of B. catarrhalis in tests for nitrate reduction and hydrolysis of tributyrin and DNase. B. catarrhalis is currently recognized as the third most frequent cause of acute otitis media and acute sinusitis in young children. It often causes acute exacerbations of chronic bronchopulmonary disease in older or immunocompromised adults and is incriminated occasionally in meningitis, endocarditis, bacteremia, conjunctivitis, keratitis, and urogenital infections. Virulence-associated factors, such as pili, capsules, outer membrane vesicles, iron acquisition proteins, histamine-synthesizing ability, resistance to the bactericidal action of normal human serum, and binding to the C1q complement component, have been identified in some strains. beta-Lactamase producing strains, first detected in 1976, have risen to approximately 75% worldwide. Thus far, however, practically all American strains of B. catarrhalis remain susceptible to alternative antibiotics. A possible selective advantage of recent isolates is their reportedly heightened tendency for adherence to oropharyngeal cells from patients with chronic bronchopulmonary disease.
Topics: Bacterial Infections; Humans; Moraxella catarrhalis; Virulence
PubMed: 2121328
DOI: 10.1128/CMR.3.4.293 -
Antimicrobial Agents and Chemotherapy Jan 2001The activity of the ketolide ABT-773 against Haemophilus and Moraxella was compared to those of 11 other agents. Against 210 Haemophilus influenzae strains (39.0%...
The activity of the ketolide ABT-773 against Haemophilus and Moraxella was compared to those of 11 other agents. Against 210 Haemophilus influenzae strains (39.0% beta-lactamase positive), microbroth dilution tests showed that azithromycin and ABT-773 had the lowest MICs (0.5 to 4.0 and 1.0 to 8.0 microg/ml, respectively), followed by clarithromycin and roxithromycin (4.0 to >32.0 microg/ml). Of the beta-lactams, ceftriaxone had the lowest MICs (=0.004 to 0.016 microg/ml), followed by cefixime and cefpodoxime (0.008 to 0.125 and =0.125 to 0.25 microg/ml, respectively), amoxicillin-clavulanate (0.125 to 4.0 microg/ml), and cefuroxime (0. 25 to 8.0 microg/ml). Amoxicillin was only active against beta-lactamase-negative strains, and cefprozil had the highest MICs of all oral cephalosporins tested (0.5 to >32.0 microg/ml). Against 50 Moraxella catarrhalis strains, all of the compounds except amoxicillin and cefprozil were active. Time-kill studies against 10 H. influenzae strains showed that ABT-773, at two times the MIC, was bactericidal against 9 of 10 strains, with 99% killing of all strains at the MIC after 24 h; at 12 h, ABT-773 gave 90% killing of all strains at two times the MIC. At 3 and 6 h, killing by ABT-773 was slower, with 99.9% killing of four strains at two times the MIC after 6 h. Similar results were found for azithromycin, with slightly slower killing by erythromycin, clarithromycin, and roxithromycin, especially at earlier times. beta-Lactams were bactericidal against 8 to 10 strains at two times the MIC after 24 h, with slower killing at earlier time periods. Most compounds gave good killing of five M. catarrhalis strains, with beta-lactams killing more rapidly than other drugs. ABT-773 and azithromycin gave the longest postantibiotic effects (PAEs) of the ketolide-macrolide-azalide group tested (4.4 to >8.0 h), followed by clarithromycin, erythromycin, and roxithromycin. beta-Lactam PAEs were similar and shorter than those of the ketolide-macrolide-azalide group for all strains tested.
Topics: Anti-Bacterial Agents; Erythromycin; Haemophilus influenzae; Ketolides; Microbial Sensitivity Tests; Moraxella catarrhalis; Time Factors
PubMed: 11120946
DOI: 10.1128/AAC.45.1.67-72.2001 -
Carbohydrate Polymers May 2024Published work has shown that glycoconjugate vaccines, based on truncated detoxified lipopolysaccharides from Moraxella catarrhalis attached through their reducing end...
Published work has shown that glycoconjugate vaccines, based on truncated detoxified lipopolysaccharides from Moraxella catarrhalis attached through their reducing end to a carrier protein, gave good protection for all three serotypes A, B, and C in mice immunisation experiments. The (from the non-reducing end) truncated LPS structures were obtained from bacterial glycosyl transferase knock-out mutants and contained the de-esterified Lipid A, two Kdo residues and five glucose moieties. This work describes the chemical synthesis of the same outer Moraxella LPS structures, spacer-equipped and further truncated from the reducing end, i.e., without the Lipid A part and containing four or five glucose moieties or four glucose moieties and one Kdo residue, and their subsequent conjugation to a carrier protein via a five‑carbon bifunctional spacer to form glycoconjugates. Immunisation experiments both in mice and rabbits of these gave a good antibody response, being 2-7 times that of pre-immune sera. However, the sera produced only recognized the immunizing glycan immunogens and failed to bind to native LPS or whole bacterial cells. Comparative molecular modelling of three alternative antigens shows that an additional (2 → 4)-linked Kdo residue, not present in the synthetic structures, has a significant impact on the shape and volume of the molecule, with implications for antigen binding and cross-reactivity.
Topics: Rabbits; Animals; Mice; Lipopolysaccharides; Moraxella catarrhalis; Lipid A; Antibodies, Bacterial; Glycoconjugates; Oligosaccharides; Glucose; Carrier Proteins
PubMed: 38431400
DOI: 10.1016/j.carbpol.2024.121928 -
Journal of Veterinary Diagnostic... Sep 2018Infectious bovine keratoconjunctivitis (IBK) is an economically significant disease caused by Moraxella bovis. Moraxella bovoculi, although not reported to cause IBK,...
Infectious bovine keratoconjunctivitis (IBK) is an economically significant disease caused by Moraxella bovis. Moraxella bovoculi, although not reported to cause IBK, has been isolated from the eyes of cattle diagnosed with IBK. Identification of M. bovis and M. bovoculi can be performed using biochemical or DNA-based approaches, both of which may be time consuming and inconsistent between laboratories. We conducted a comparative evaluation of M. bovoculi and M. bovis identification using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI-TOF MS) with a database provided by Bruker Daltonics (termed the BDAL database), the BDAL database supplemented with spectra generated in our study (termed the UNLVDC database), and with PCR-restriction-fragment length polymorphism (PCR-RFLP) typing. M. bovoculi ( n = 250) and M. bovis ( n = 18) isolates from cattle with or without IBK were used. MALDI-TOF MS using the UNLVDC database correctly identified 250 of 250 (100%) of M. bovoculi and 17 of 18 (94%) of M. bovis isolates. With the BDAL database, MALDI-TOF MS correctly identified 249 of 250 (99%) of M. bovoculi and 7 of 18 (39%) of M. bovis isolates. In comparison, the PCR-RFLP test correctly identified 210 of 250 (84%) of M. bovoculi and 12 of 18 (66%) of M. bovis isolates. Thus, MALDI-TOF MS with the UNLVDC database was the most effective identification methodology for M. bovis and M. bovoculi isolates from cattle.
Topics: Animals; Cattle; Cattle Diseases; Databases, Factual; Keratoconjunctivitis, Infectious; Mass Spectrometry; Moraxella; Moraxella bovis; Moraxellaceae Infections; Polymerase Chain Reaction; Polymorphism, Restriction Fragment Length; Sensitivity and Specificity; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
PubMed: 30027824
DOI: 10.1177/1040638718789725 -
BMJ Case Reports Apr 2021
Topics: Hockey; Humans; Moraxella catarrhalis; Moraxellaceae Infections
PubMed: 33931430
DOI: 10.1136/bcr-2021-243677 -
MSphere Jul 2020, , and nontypeable (NTHi) are ubiquitous upper respiratory opportunistic pathogens. Together, these three microbes are the most common causative bacterial agents of...
, , and nontypeable (NTHi) are ubiquitous upper respiratory opportunistic pathogens. Together, these three microbes are the most common causative bacterial agents of pediatric otitis media (OM) and have therefore been characterized as the primary human otopathogens. OM is the most prevalent bacterial infection in children and the primary reason for antibiotic administration in this population. Moreover, biofilm formation has been confirmed as a primary mechanism of chronic and recurrent OM disease. As bacterial biofilms are inherently metabolically recalcitrant to most antibiotics and these complex structures also present a significant challenge to the immune system, there is a clear need to identify novel antimicrobial approaches to treat OM infections. In this study, we evaluated the potential efficacy of antibacterial photodynamic therapy (aPDT) with the photosensitizer chlorin e6 (Ce6) against planktonic as well as biofilm-associated , , and NTHi. Our data indicate aPDT with Ce6 elicits significant bactericidal activity against both planktonic cultures and established biofilms formed by the three major otopathogens (with an efficacy of ≥99.9% loss of viability). Notably, the implementation of a novel, dual-treatment aPDT protocol resulted in this disinfectant effect on biofilm-associated bacteria and, importantly, inhibited bacterial regrowth 24 h posttreatment. Taken together, these data suggest this novel Ce6-aPDT treatment may be a powerful and innovative therapeutic strategy to effectively treat and eradicate bacterial OM infections and, significantly, prevent the development of recurrent disease. Otitis media (OM), or middle ear disease, is the most prevalent bacterial infection in children and the primary reason for antibiotic use and surgical intervention in the pediatric population. Biofilm formation by the major bacterial otopathogens, , , and nontypeable , has been shown to occur within the middle ears of OM patients and is a key factor in the development of recurrent disease, which may result in hearing impairment and developmental delays. Bacterial biofilms are inherently impervious to most antibiotics and present a significant challenge to the immune system. In this study, we demonstrate that antimicrobial photodynamic therapy (aPDT) using the photosensitizer chlorin e6 elicits significant bactericidal activity versus planktonic and biofilm-associated otopathogens and supports further analyses of this novel, efficacious, and promising technology as an adjunctive treatment for acute and recurrent OM.
Topics: Anti-Bacterial Agents; Bacteria; Biofilms; Chlorophyllides; Haemophilus influenzae; Humans; Microbial Viability; Moraxella catarrhalis; Otitis Media; Photochemotherapy; Porphyrins; Streptococcus pneumoniae
PubMed: 32669474
DOI: 10.1128/mSphere.00492-20 -
International Journal of Chronic... 2018is implicated in the pathogenesis of some COPD exacerbations. We sought to investigate whether the strain is variable between COPD subjects; that an exacerbation is...
PURPOSE
is implicated in the pathogenesis of some COPD exacerbations. We sought to investigate whether the strain is variable between COPD subjects; that an exacerbation is associated with acquisition of a new strain and that certain strains are more commonly associated with exacerbations.
PATIENTS AND METHODS
Sputum samples were collected at stable and exacerbation visits from COPD subjects from a single center as part of the COPDMAP consortium. Samples identified as positive by qPCR were recultured in liquid cultures grown to extract genomic DNA; underwent Illumina MiSeq and bacterial genome sequences were de novo assembled and Multi Locus Sequence Type (MLST) was determined.
RESULTS
Thirty-five samples were obtained from 18 subjects. These included 13 stable and 22 exacerbation samples. The diversity between samples was very large with 25 different MLSTs being identified out of the 35 samples of which 12 MSLTs have not been described previously. Change and persistence of strain were observed between stable visits, from stable to exacerbation and vice-a-versa, and between exacerbation visits.
CONCLUSION
Sputum strains exhibit marked diversity within and between COPD subjects. Acquisition of a new strain is common between stable and exacerbation events such that no strain is specifically associated with an exacerbation.
Topics: Aged; DNA, Bacterial; Disease Progression; Female; Genotype; Humans; Lung; Male; Middle Aged; Moraxella catarrhalis; Moraxellaceae Infections; Phenotype; Pulmonary Disease, Chronic Obstructive; Respiratory Tract Infections; Sputum
PubMed: 30510409
DOI: 10.2147/COPD.S180961 -
Journal of Clinical Microbiology Mar 1988We determined phenotypic characteristics, cellular fatty acid composition, and isoprenoid quinone content of representative strains of CDC groups EO-2, M-5, and M-6,...
Cultural and chemical characterization of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis.
We determined phenotypic characteristics, cellular fatty acid composition, and isoprenoid quinone content of representative strains of CDC groups EO-2, M-5, and M-6, Moraxella (Moraxella) species, Oligella urethralis, Acinetobacter species, and Psychrobacter immobilis. All organisms contained ubiquinone with eight isoprene units as the major isoprenolog, but distinct differences were observed in fatty acid composition. Twenty-eight of the original collection of CDC group EO-2 strains were further identified as P. immobilis, EO-2, or EO-3 by distinctive cellular fatty acid profiles, cellular morphology, and pigment production. The cellular fatty acid compositions of M-5 and M-6 were similar but were clearly different from those of other organisms. The genus Acinetobacter was differentiated from other organisms in the study by small amounts of 2-hydroxydodecanoic acid (2-OH-12:0), and P. immobilis was differentiated by small amounts of decanoic acid (10:0) and a branched-chain 17-carbon acid (i-17:0). All Moraxella species were distinguished by small amounts of decanoic acid (10:0) and the absence of i-17:0. M. bovis, M. nonliquefaciens, and some strains of M. lacunata formed a single fatty acid group, while M. osloensis, M. phenylpyruvica, M. atlantae, and other strains of M. lacunata (M. lacunata II) had species-specific fatty acid profiles. O. urethralis differed from Moraxella species by the presence of large amounts (49%) of cis-vaccenic acid (18:1 omega 7c), small amounts (1%) of 3-hydroxyhexadecanoate (3-OH-16:0), and the absence of 10:0 and 3-hydroxydodecanoate (3-OH-12:0). The combined use of chemical data and a small number of conventional tests permitted rapid identification and differentiation of these organisms from each other and from related organisms.
Topics: Acinetobacter; Animals; Chromatography, Gas; Fatty Acids; Gram-Negative Bacteria; Humans; Minicomputers; Moraxella; Software; Transformation, Bacterial
PubMed: 3356788
DOI: 10.1128/jcm.26.3.484-492.1988