Activity

Jeff Collins is a physician scientist in the Division of Infectious Diseases at Emory University focused on using metabolomics and systems biology to better understand the pathophysiology of tuberculosis disease, identify new biomarkers, and elucidate targets for host-directed therapeutics. In this mSphere of Influence article, he reflects on how the paper “Succinate is an inflammatory signal that induces IL-1β through HIF-1α” by Tannahill et al. (G. M. Tannahill, A. M. Curtis, J. Adamik, E. M. Palsson-McDermott, et al., Nature 496238-242, 2013, https//doi.org/10.1038/nature11986) influenced him by highlighting the intersection between metabolism and the host response to infectious diseases.The study of gene expression in fungi has typically relied on measuring transcripts in populations of cells. A major disadvantage of this approach is that the transcripts’ spatial distribution and stochastic variation among individual cells within a clonal population is lost. Traditional fluorescence in situ hybridization techniques have been of limited use in fungi due to poor specificity and high background signal. selleck chemicals Here, we report that in situ hybridization chain reaction (HCR), a method that employs split-initiator probes to trigger signal amplification upon mRNA-probe hybridization, is ideally suited for the imaging and quantification of low-abundance transcripts at single-cell resolution in the fungus Candida albicans. We show that HCR allows the absolute quantification of transcripts within a cell by microscopy as well as their relative quantification by flow cytometry. mRNA imaging also revealed the subcellular localization of specific transcripts. Furthermore, we establish that HCR is amenable to mult process requires microbial cell-optimized procedures to image and measure mRNAs at single-molecule resolution. In this report, we adapt and expand in situ hybridization chain reaction (HCR) combined with split-initiator probes to visualize transcripts in the human-pathogenic fungus Candida albicans at high resolution.Dengue virus serotype 4 (DENV-4) circulated in Aedes aegypti in 2016 and 2017 in Florida in the absence of human index cases, compelling a full assessment of local mosquito vector competence and DENV-4 risk. To better understand DENV-4 transmission risk in Florida, we used an expanded suite of tests to measure and compare the vector competencies of both an established colony of A. aegypti (Orlando strain [ORL]) and a field-derived colony from Collier County, FL, in 2018 (COL) for a Haitian DENV-4 human field isolate and a DENV-4 laboratory strain (Philippines H241). We immediately noted that ORL saliva positivity was higher for the field than for laboratory DENV-4 strains. In a subsequent comparison with the recent COL mosquito colony, we also observed significantly higher midgut infection of COL and ORL by the Haitian DENV-4 field strain and a significantly higher saliva positivity rate for COL, although overall saliva virus titers were similar between the two. These data point to a potential midgut infectios to the possible mechanism of undetected DENV-4 maintenance in the state. Our findings also move the field forward in the development of best practices for evaluating arbovirus vector competence, with evidence that transmission potential estimates vary depending on the mosquito-virus combinations. These data emphasize the poor suitability of laboratory-established virus strains and the high relevance of field-derived mosquito populations in estimating transmission risk.Cholera caused by Vibrio cholerae O139 could reemerge, and proactive development of an effective O139 vaccine would be prudent. To define immunoreactive and potentially immunogenic carbohydrate targets of Vibrio cholerae O139, we assessed immunoreactivities of various O-specific polysaccharide (OSP)-related saccharides with plasma from humans hospitalized with cholera caused by O139, comparing responses to those induced in recipients of a commercial oral whole-cell killed bivalent (O1 and O139) cholera vaccine (WC-O1/O139). We also assessed conjugate vaccines containing selected subsets of these saccharides for their ability to induce protective immunity using a mouse model of cholera. We found that patients with wild-type O139 cholera develop IgM, IgA, and IgG immune responses against O139 OSP and many of its fragments, but we were able to detect only a moderate IgM response to purified O139 OSP-core, and none to its fragments, in immunologically naive recipients of WC-O1/O139. We found that immunoreactivityttle is known about immunity to O139 OSP. In this study, we used synthetic fragments of the O139 OSP to define immune responses to OSP in humans recovering from cholera caused by V. cholerae O139, compared these responses to those induced by the available O139 vaccine, and evaluated O139 fragments in next-generation conjugate vaccines. We found that the terminal tetrasaccharide of O139 is a primary immune target but that the currently available bivalent cholera vaccine poorly induces an anti-O139 OSP response in immunologically naive individuals.Coxiella burnetii is a highly infectious, intracellular, Gram-negative bacterial pathogen that causes human Q fever, an acute flu-like illness that can progress to chronic endocarditis. C. burnetii is transmitted to humans via aerosols and has long been considered a potential biological warfare agent. Although antibiotics, such as doxycycline, effectively treat acute Q fever, a recently identified antibiotic-resistant strain demonstrates the ability of C. burnetii to resist traditional antimicrobials, and chronic disease is extremely difficult to treat with current options. These findings highlight the need for new Q fever therapeutics, and repurposed drugs that target eukaryotic functions to prevent bacterial replication are of increasing interest in infectious disease. To identify this class of anti-C. burnetii therapeutics, we screened a library of 727 FDA-approved or late-stage clinical trial compounds using a human macrophage-like cell model of infection. Eighty-eight compounds inhibited bacterial replication, including known antibiotics, antipsychotic or antidepressant treatments, antihistamines, and several additional compounds used to treat a variety of conditions.