scholarly journals RNA and Sugars, Unique Properties of Bacteriophages Infecting Multidrug Resistant Acinetobacter radioresistens Strain LH6

Viruses ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1652
Author(s):  
Clay S. Crippen ◽  
Bibi Zhou ◽  
Silke Andresen ◽  
Robert T. Patry ◽  
Artur Muszyński ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Capsular Polysaccharide ◽  
Multidrug Resistant ◽  
Resistant Isolate ◽  
Biological Entity ◽  
Dna Viruses ◽  
Host Interactions ◽  
Acinetobacter Radioresistens ◽  
Bacterial Mutagenesis ◽  
Pilin Protein

Bacteriophages (phages) are predicted to be the most ubiquitous biological entity on earth, and yet, there are still vast knowledge gaps in our understanding of phage diversity and phage–host interactions. Approximately one hundred Acinetobacter-infecting DNA viruses have been identified, and in this report, we describe eight more. We isolated two typical dsDNA lytic podoviruses (CAP1–2), five unique dsRNA lytic cystoviruses (CAP3–7), and one dsDNA lysogenic siphovirus (SLAP1), all capable of infecting the multidrug resistant isolate Acinetobacter radioresistens LH6. Using transmission electron microscopy, bacterial mutagenesis, phage infectivity assays, carbohydrate staining, mass-spectrometry, genomic sequencing, and comparative studies, we further characterized these phages. Mutation of the LH6 initiating glycosyltransferase homolog, PglC, necessary for both O-linked glycoprotein and capsular polysaccharide (CPS) biosynthesis, prevented infection by the lytic podovirus CAP1, while mutation of the pilin protein, PilA, prevented infection by CAP3, representing the lytic cystoviruses. Genome sequencing of the three dsRNA segments of the isolated cystoviruses revealed low levels of homology, but conserved synteny with the only other reported cystoviruses that infect Pseudomonas species. In Pseudomonas, the cystoviruses are known to be enveloped phages surrounding their capsids with the inner membrane from the infected host. To characterize any membrane-associated glycoconjugates in the CAP3 cystovirus, carbohydrate staining was used to identify a low molecular weight lipid-linked glycoconjugate subsequently identified by mutagenesis and mass-spectrometry as bacterial lipooligosaccharide. Together, this study demonstrates the isolation of new Acinetobacter-infecting phages and the determination of their cell receptors. Further, we describe the genomes of a new genus of Cystoviruses and perform an initial characterization of membrane-associated glycoconjugates.

scholarly journals Viruses go modular

2020 ◽  
Vol 295 (14) ◽  
pp. 4604-4616 ◽  
Author(s):  
Ariel Shepley-McTaggart ◽  
Hao Fan ◽  
Marius Sudol ◽  
Ronald N. Harty
Keyword(s):  
Hippo Pathway ◽  
Host Proteins ◽  
Dna Viruses ◽  
Ww Domain ◽  
Ww Domains ◽  
Host Interactions ◽  
New Class ◽  
Domain Interactions ◽  
Molecular Aspects ◽  
The Hippo Pathway

The WW domain is a modular protein structure that recognizes the proline-rich Pro-Pro-x-Tyr (PPxY) motif contained in specific target proteins. The compact modular nature of the WW domain makes it ideal for mediating interactions between proteins in complex networks and signaling pathways of the cell (e.g. the Hippo pathway). As a result, WW domains play key roles in a plethora of both normal and disease processes. Intriguingly, RNA and DNA viruses have evolved strategies to hijack cellular WW domain–containing proteins and thereby exploit the modular functions of these host proteins for various steps of the virus life cycle, including entry, replication, and egress. In this review, we summarize key findings in this rapidly expanding field, in which new virus-host interactions continue to be identified. Further unraveling of the molecular aspects of these crucial virus-host interactions will continue to enhance our fundamental understanding of the biology and pathogenesis of these viruses. We anticipate that additional insights into these interactions will help support strategies to develop a new class of small-molecule inhibitors of viral PPxY-host WW-domain interactions that could be used as antiviral therapeutics.

scholarly journals Draft Genome Sequence of Streptococcus agalactiae Serotype Ia Strain M19, a Multidrug-Resistant Isolate from a Cow with Bovine Mastitis

2016 ◽  
Vol 4 (6) ◽  
Author(s):  
Feng Yang ◽  
Hongsheng Li ◽  
Shidong Zhang ◽  
Xurong Wang
Keyword(s):  
Genome Sequence ◽  
Streptococcus Agalactiae ◽  
Draft Genome ◽  
Bovine Mastitis ◽  
Multidrug Resistant ◽  
Draft Genome Sequence ◽  
Resistant Isolate ◽  
Draft Sequence ◽  
Autonomous Region ◽  
Ningxia Hui Autonomous Region

Streptococcus agalactiae is a major contagious pathogen causing bovine mastitis worldwide. We report here the draft sequence of S. agalactiae Ia strain M19, a multidrug-resistant isolate from a bovine mastitis case in Ningxia Hui autonomous region, China.

scholarly journals Human anelloviruses: diverse, omnipresent and commensal members of the virome

2020 ◽  
Vol 44 (3) ◽  
pp. 305-313 ◽  
Author(s):  
Joanna Kaczorowska ◽  
Lia van der Hoek
Keyword(s):  
Beneficial Effect ◽  
Culture System ◽  
Human Population ◽  
Human Life ◽  
Disease Association ◽  
Viral Clearance ◽  
Early Age ◽  
Dna Viruses ◽  
Circular Dna ◽  
Host Interactions

ABSTRACT Anelloviruses are small, single stranded circular DNA viruses. They are extremely diverse and have not been associated with any disease so far. Strikingly, these small entities infect most probably the complete human population, and there are no convincing examples demonstrating viral clearance from infected individuals. The main transmission could be via fecal-oral or airway route, as infections occur at an early age. However, due to the lack of an appropriate culture system, the virus–host interactions remain enigmatic. Anelloviruses are obviously mysterious viruses, and their impact on human life is not yet known, but, with no evidence of a disease association, a potential beneficial effect on human health should also be investigated.

scholarly journals Genome Sequence of Resistant Serratia sp. Strain HRI, Isolated from a Bottle of Didecyldimethylammonium Chloride-Based Disinfectant

2020 ◽  
Vol 9 (18) ◽  
Author(s):  
Samantha J. Mc Carlie ◽  
Julius E. Hellmuth ◽  
Jeffrey Newman ◽  
Charlotte E. Boucher ◽  
Robert R. Bragg
Keyword(s):  
Antimicrobial Resistance ◽  
Genome Sequence ◽  
Bacterial Infections ◽  
Multidrug Resistant ◽  
Whole Genome Sequence ◽  
Resistant Isolate ◽  
Resistant Bacteria ◽  
Hybrid Assembly ◽  
Pacbio Sequencing ◽  
Didecyldimethylammonium Chloride

Antimicrobial resistance is a significant issue, and it threatens the prevention and effective treatment of a range of bacterial infections. Here, we report the whole-genome sequence of the multidrug-resistant isolate Serratia sp. strain HRI. A hybrid assembly was created using sequences from a first (MiSeq) and second (PacBio) sequencing run. This work is imperative for understanding antimicrobial resistance and adds to the knowledge base for combating multidrug-resistant bacteria.

scholarly journals Global Proteomic Profiling ofSalmonellaInfection by a Giant Phage

2018 ◽  
Vol 93 (5) ◽  
Author(s):  
Susan T. Weintraub ◽  
Nurul Humaira Mohd Redzuan ◽  
Melissa K. Barton ◽  
Nur Amira Md Amin ◽  
Maxim I. Desmond ◽  
...  
Keyword(s):  
Mass Spectrometry ◽  
Multidrug Resistant ◽  
Scaffold Protein ◽  
Gene Products ◽  
Proteomic Profiling ◽  
Content Type ◽  
Mass Spectral ◽  
Head Assembly ◽  
Infected Cells

ABSTRACTThe 240-kbSalmonellaphage SPN3US genome encodes 264 gene products, many of which are functionally uncharacterized. We have previously used mass spectrometry to define the proteomes of wild-type and mutant forms of the SPN3US virion. In this study, we sought to determine whether this technique was suitable for the characterization of the SPN3US proteome during liquid infection. Mass spectrometry of SPN3US-infected cells identified 232 SPN3US and 1,994Salmonellaproteins. SPN3US proteins with related functions, such as proteins with roles in DNA replication, transcription, and virion formation, were coordinately expressed in a temporal manner. Mass spectral counts showed the four most abundant SPN3US proteins to be the major capsid protein, two head ejection proteins, and the functionally unassigned protein gp22. This high abundance of gp22 in infected bacteria contrasted with its absence from mature virions, suggesting that it might be the scaffold protein, an essential head morphogenesis protein yet to be identified in giant phages. We identified homologs to SPN3US gp22 in 45 related giant phages, including ϕKZ, whose counterpart is also abundant in infected bacteria but absent in the virion. We determined the ϕKZ counterpart to be cleavedin vitroby its prohead protease, an event that has been observed to promote head maturation of some other phages. Our findings are consistent with a scaffold protein assignment for SPN3US gp22, although direct evidence is required for its confirmation. These studies demonstrate the power of mass spectral analyses for facilitating the acquisition of new knowledge into the molecular events of viral infection.IMPORTANCE“Giant” phages with genomes >200 kb are being isolated in increasing numbers from a range of environments. With hosts such asSalmonella enterica,Pseudomonas aeruginosa, andErwinia amylovora, these phages are of interest for phage therapy of multidrug-resistant pathogens. However, our understanding of how these complex phages interact with their hosts is impeded by the proportion (∼80%) of their gene products that are functionally uncharacterized. To develop the repertoire of techniques for analysis of phages, we analyzed a liquid infection ofSalmonellaphage SPN3US (240-kb genome) using third-generation mass spectrometry. We observed the temporal production of phage proteins whose genes collectively represent 96% of the SPN3US genome. These findings demonstrate the sensitivity of mass spectrometry for global proteomic profiling of virus-infected cells, and the identification of a candidate for a major head morphogenesis protein will facilitate further studies into giant phage head assembly.

scholarly journals Development of Opsonic Mouse Monoclonal Antibodies against Multidrug-Resistant Enterococci

2019 ◽  
Vol 87 (9) ◽  
Author(s):  
Ermioni Kalfopoulou ◽  
Diana Laverde ◽  
Karmela Miklic ◽  
Felipe Romero-Saavedra ◽  
Suzana Malic ◽  
...  
Keyword(s):  
Monoclonal Antibodies ◽  
Capsular Polysaccharide ◽  
Selection Process ◽  
Multidrug Resistant ◽  
Expression Vectors ◽  
Hybridoma Cells ◽  
Enzyme Linked Immunosorbent Assay ◽  
Bacterial Strains ◽  
Variable Regions ◽  
Content Type

ABSTRACTMultidrug-resistant enterococci are major causes of hospital-acquired infections. Immunotherapy with monoclonal antibodies (MAbs) targeting bacterial antigens would be a valuable treatment option in this setting. Here, we describe the development of two MAbs through hybridoma technology that target antigens from the most clinically relevant enterococcal species. Diheteroglycan (DHG), a well-characterized capsular polysaccharide ofEnterococcus faecalis, and the secreted antigen A (SagA), an immunogenic protein fromEnterococcus faecium, are both immunogens that have been proven to raise opsonic and cross-reactive antibodies against enterococcal strains. For this purpose, a conjugated form of the native DHG with SagA was used to raise the antibodies in mice, while enzyme-linked immunosorbent assay and opsonophagocytic assay were combined in the selection process of hybridoma cells producing immunoreactive and opsonic antibodies targeting the selected antigens. From this process, two highly specific IgG1(κ) MAbs were obtained, one against the polysaccharide (DHG.01) and one against the protein (SagA.01). Both MAbs exhibited good opsonic killing against the target bacterial strains: DHG.01 showed 90% killing againstE. faecalistype 2, and SagA.01 showed 40% killing againstE. faecium11231/6. In addition, both MAbs showed cross-reactivity toward otherE. faecalisandE. faeciumstrains. The sequences from the variable regions of the heavy and light chains were reconstructed in expression vectors, and the activity of the MAbs upon expression in eukaryotic cells was confirmed with the same immunological assays. In summary, we identified two opsonic MAbs against enterococci which could be used for therapeutic or prophylactic approaches against enterococcal infections.

scholarly journals Emergence of Multidrug-Resistant Salmonella enterica Serovar Typhi in Korea

2004 ◽  
Vol 48 (11) ◽  
pp. 4130-4135 ◽  
Author(s):  
Kyungwon Lee ◽  
Dongeun Yong ◽  
Jong Hwa Yum ◽  
Young Sik Lim ◽  
Hyun Sook Kim ◽  
...  
Keyword(s):  
Salmonella Enterica ◽  
Antimicrobial Agents ◽  
Susceptibility Testing ◽  
Multidrug Resistant ◽  
Resistant Isolate ◽  
Asian Countries ◽  
Gene Cassettes ◽  
Salmonella Enterica Serovar Typhi ◽  
Class 1 ◽  
Selection Of

ABSTRACT A chloramphenicol-resistant strain of Salmonella enterica serovar Typhi was first noted in Korea in 1992, when a resistant isolate was detected in a returned traveler. Continued isolation of multidrug-resistant (MDR) strains thereafter in other settings prompted a retrospective analysis of laboratory records and phenotypic and genotypic analyses of 12 chloramphenicol-resistant isolates. Among these, one isolate was resistant only to chloramphenicol, and the other isolates were also resistant to ampicillin and co-trimoxazole. MDR was transferred by conjugation from 9 of the 11 isolates. PCR showed that all isolates had an incompatible group HI1 plasmid, and oriT was detected in 10 isolates, which included strains with an unsuccessful transfer of resistance. All of the ampicillin-resistant isolates had a β-lactamase band of pI 5.4 and bla TEM alleles. A PCR amplicon from an isolate showed that the sequences were identical to those of bla TEM-1, suggesting that all isolates had a TEM-1 β-lactamase. All isolates had class 1 integrons: 10 isolates had integrons of ca. 1.2 kb with dhfr7 gene cassettes, and 1 isolate had an integron of ca. 2.3 kb with aacA4 and bla OXA-1-like gene cassettes. The pulsed-field gel electrophoresis patterns of 7 of 11 MDR isolates were identical and indistinguishable from those reported for isolates in India and Indonesia. In conclusion, some of the MDR strains in Korea are related to those in other Asian countries. Susceptibility testing became necessary for selection of antimicrobial agents for the optimal treatment of patients with the emergence of MDR Salmonella serovar Typhi in Korea.

scholarly journals Optimization of Synergistic Combination Regimens against Carbapenem- and Aminoglycoside-Resistant Clinical Pseudomonas aeruginosa Isolates via Mechanism-Based Pharmacokinetic/Pharmacodynamic Modeling

2016 ◽  
Vol 61 (1) ◽  
Author(s):  
Rajbharan Yadav ◽  
Jürgen B. Bulitta ◽  
Roger L. Nation ◽  
Cornelia B. Landersdorfer
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Multidrug Resistant ◽  
Viable Count ◽  
Resistant Isolate ◽  
Pharmacodynamic Modeling ◽  
Combination Regimen ◽  
Bacterial Killing ◽  
Content Type ◽  
Dosage Regimens ◽  
Combination Regimens

ABSTRACT Optimizing antibiotic combinations is promising to combat multidrug-resistant Pseudomonas aeruginosa. This study aimed to systematically evaluate synergistic bacterial killing and prevention of resistance by carbapenem and aminoglycoside combinations and to rationally optimize combination dosage regimens via a mechanism-based mathematical model (MBM). We studied monotherapies and combinations of imipenem with tobramycin or amikacin against three difficult-to-treat double-resistant clinical P. aeruginosa isolates. Viable-count profiles of total and resistant populations were quantified in 48-h static-concentration time-kill studies (inoculum, 107.5 CFU/ml). We rationally optimized combination dosage regimens via MBM and Monte Carlo simulations against isolate FADDI-PA088 (MIC of imipenem [MICimipenem] of 16 mg/liter and MICtobramycin of 32 mg/liter, i.e., both 98th percentiles according to the EUCAST database). Against this isolate, imipenem (1.5× MIC) combined with 1 to 2 mg/liter tobramycin (MIC, 32 mg/liter) or amikacin (MIC, 4 mg/liter) yielded ≥2-log10 more killing than the most active monotherapy at 48 h and prevented resistance. For all three strains, synergistic killing without resistance was achieved by ≥0.88× MICimipenem in combination with a median of 0.75× MICtobramycin (range, 0.032× to 2.0× MICtobramycin) or 0.50× MICamikacin (range, 0.25× to 0.50× MICamikacin). The MBM indicated that aminoglycosides significantly enhanced the imipenem target site concentration up to 3-fold; achieving 50% of this synergistic effect required aminoglycoside concentrations of 1.34 mg/liter (if the aminoglycoside MIC was 4 mg/liter) and 4.88 mg/liter (for MICs of 8 to 32 mg/liter). An optimized combination regimen (continuous infusion of imipenem at 5 g/day plus a 0.5-h infusion with 7 mg/kg of body weight tobramycin) was predicted to achieve >2.0-log10 killing and prevent regrowth at 48 h in 90.3% of patients (median bacterial killing, >4.0 log10 CFU/ml) against double-resistant isolate FADDI-PA088 and therefore was highly promising.

scholarly journals Unique structure and function of viral rhodopsins

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Dmitry Bratanov ◽  
Kirill Kovalev ◽  
Jan-Philipp Machtens ◽  
Roman Astashkin ◽  
Igor Chizhov ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Structure And Function ◽  
Proton Donor ◽  
Dna Viruses ◽  
Host Interactions ◽  
Hydrophobic Barrier ◽  
High Resolution Structure ◽  
Group 2 ◽  
Marine Protists ◽  
And Function

Abstract Recently, two groups of rhodopsin genes were identified in large double-stranded DNA viruses. The structure and function of viral rhodopsins are unknown. We present functional characterization and high-resolution structure of an Organic Lake Phycodnavirus rhodopsin II (OLPVRII) of group 2. It forms a pentamer, with a symmetrical, bottle-like central channel with the narrow vestibule in the cytoplasmic part covered by a ring of 5 arginines, whereas 5 phenylalanines form a hydrophobic barrier in its exit. The proton donor E42 is placed in the helix B. The structure is unique among the known rhodopsins. Structural and functional data and molecular dynamics suggest that OLPVRII might be a light-gated pentameric ion channel analogous to pentameric ligand-gated ion channels, however, future patch clamp experiments should prove this directly. The data shed light on a fundamentally distinct branch of rhodopsins and may contribute to the understanding of virus-host interactions in ecologically important marine protists.

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