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Browsing by Author "May, Meghan"
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Item Characterization of Pontibacter altruii, sp. nov., isolated from a human blood culture(Elsevier, 2017-09) Roiko, Marijo; May, Meghan; Relich, Ryan F.; Department of Pathology and Laboratory Medicine, IU School of MedicineThe genus Pontibacter is a recent addition to the family Cytophagaceae, phylum Bacteroidetes. Previous reports of its cultivation and molecular detection are from a variety of environmental sources, including marine and desert habitats. We report the first description of a Pontibacter sp., which was initially identified as Elizabethkingia meningoseptica, isolated from a human clinical specimen. On the basis of 16S rRNA gene sequence, unique mass spectral profile and phenotypic characterization, this isolate represents a novel species within the genus Pontibacter that has been named Pontibacter altruii, sp. nov., strain Grand Forks.Item A Comprehensive Systems Biology Approach to Studying Zika Virus(Plos, 2016-09) Relich, Ryan F.; May, Meghan; Department of Pathology and Laboratory Medicine, IU School of MedicineZika virus (ZIKV) is responsible for an ongoing and intensifying epidemic in the Western Hemisphere. We examined the complete predicted proteomes, glycomes, and selectomes of 33 ZIKV strains representing temporally diverse members of the African lineage, the Asian lineage, and the current outbreak in the Americas. Derivation of the complete selectome is an 'omics' approach to identify distinct evolutionary pressures acting on different features of an organism. Employment of the M8 model did not show evidence of global diversifying selection acting on the ZIKV polyprotein; however, a mixed effect model of evolution showed strong evidence (P<0.05) for episodic diversifying selection acting on specific sites. Single nucleotide polymorphisms (SNPs) were predictably frequent across strains relative to the derived consensus sequence. None of the 9 published detection procedures utilize targets that share 100% identity across the 33 strains examined, indicating that ZIKV escape from molecular detection is predictable. The predicted O-linked glycome showed marked diversity across strains; however, the N-linked glycome was highly stable. All Asian and American strains examined were predicted to include glycosylation of E protein ASN154, a modification proposed to mediate neurotropism, whereas the modification was not predicted for African strains. SNP diversity, episodic diversifying selection, and differential glycosylation, particularly of ASN154, may have major biological implications for ZIKV disease. Taken together, the systems biology perspective of ZIKV indicates: a.) The recently emergent Asian/American N-glycotype is mediating the new and emerging neuropathogenic potential of ZIKV; and b.) further divergence at specific sites is predictable as endemnicity is established in the Americas.Item Induction of β-Lactamase Activity and Decreased β-Lactam Susceptibility by CO2 in Clinical Bacterial Isolates(American Society for Microbiology, 2017-07-19) Mullen, Nathan; Raposo, Hugo; Gudis, Polyxeni; Barker, Linsey; Humphries, Romney M.; Schmitt, Bryan H.; Relich, Ryan F.; May, Meghan; Pathology and Laboratory Medicine, School of MedicineAntimicrobial susceptibility testing of clinical isolates is a crucial step toward appropriate treatment of infectious diseases. The clinical isolate Francisella philomiragia 14IUHPL001, recently isolated from a 63-year-old woman with atypical pneumonia, featured decreased susceptibility to β-lactam antibiotics when cultivated in 5% CO2. Quantitative β-lactamase assays demonstrated a significant (P < 0.0001) increase in enzymatic activity between bacteria cultivated in 5% CO2 over those incubated in ambient air. The presence of β-lactamase genes blaTEM and blaSHV was detected in the clinical isolate F. philomiragia 14IUHPL001 by PCR, and the genes were positively identified by nucleotide sequencing. Expression of blaTEM and blaSHV was detected by reverse transcription-PCR during growth at 5% CO2 but not during growth in ambient air. A statistically significant alkaline shift was observed following cultivation of F. philomiragia 14IUHPL001 in both ambient air and 5% CO2, allowing desegregation of the previously reported effects of acidic pH from the currently reported effect of 5% CO2 on blaTEM and blaSHV β-lactamases. To ensure that the observed phenomenon was not unique to F. philomiragia, we evaluated a clinical isolate of blaTEM-carrying Haemophilus influenzae and found parallel induction of blaTEM gene expression and β-lactamase activity at 5% CO2 relative to ambient air. IMPORTANCE β-Lactamase induction and concurrent β-lactam resistance in respiratory tract pathogens as a consequence of growth in a physiologically relevant level of CO2 are of clinical significance, particularly given the ubiquity of TEM and SHV β-lactamase genes in diverse bacterial pathogens. This is the first report of β-lactamase induction by 5% CO2.Item A Novel Mechanism for Zika Virus Host-Cell Binding(MDPI, 2019-11-28) Rieder, Courtney A.,; Rieder, Jonathan; Sannajust, Sebastién; Goode, Diana; Geguchadze, Ramaz; Relich, Ryan F.; Molliver, Derek C.; King, Tamara E.; Vaughn, James; May, Meghan; Pathology and Laboratory Medicine, School of MedicineZika virus (ZIKV) recently emerged in the Western Hemisphere with previously unrecognized or unreported clinical presentations. Here, we identify two putative binding mechanisms of ancestral and emergent ZIKV strains featuring the envelope (E) protein residue asparagine 154 (ASN154) and viral phosphatidylserine (PS). Synthetic peptides representing the region containing ASN154 from strains PRVABC59 (Puerto Rico 2015) and MR_766 (Uganda 1947) were exposed to neuronal cells and fibroblasts to model ZIKV E protein/cell interactions and bound MDCK or Vero cells and primary neurons significantly. Peptides significantly inhibited Vero cell infectivity by ZIKV strains MR_766 and PRVABC59, indicating that this region represents a putative binding mechanism of ancestral African ZIKV strains and emergent Western Hemisphere strains. Pretreatment of ZIKV strains MR_766 and PRVABC59 with the PS-binding protein annexin V significantly inhibited replication of PRVABC59 but not MR_766, suggesting that Western hemisphere strains may additionally be capable of utilizing PS-mediated entry to infect host cells. These data indicate that the region surrounding E protein ASN154 is capable of binding fibroblasts and primary neuronal cells and that PS-mediated entry may be a secondary mechanism for infectivity utilized by Western Hemisphere strains.