380 results on '"Handelsman J"'
Search Results
52. Club foot: a neuromuscular disease.
- Author
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Handelsman, John E., Badalamente, Marie A., Handelsman, J E, and Badalamente, M A
- Published
- 1982
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53. Variable stability of antibiotic-resistance markers in Bacillus cereus UW85 in the soybean rhizosphere in the field.
- Author
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Clayton, M. K., Halverson, L. J., and Handelsman, J.
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BACILLUS thuringiensis ,GENETIC engineering - Published
- 1993
54. Cloning and Heterologous Expression of a Natural Product Biosynthetic Gene Cluster from eDNA
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Brady, S. F., Chao, C. J., Handelsman, J., and Clardy, J.
- Abstract
To study the natural products produced by uncultured microorganisms, an environmental DNA (eDNA) cosmid library was constructed and screened for the heterologous production of small molecules. A blue clone, CSL51, found in the eDNA library produces deoxyviolacein and the broad spectrum antibiotic violacein. The full sequence of the 6.7 kb eDNA violacein gene cluster and the characterization of violacein and deoxyviolacein from an eDNA clone are reported here. - Published
- 2001
55. Zwittermicin A biosynthetic cluster
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Stohl, E.A., Milner, J.L., and Handelsman, J.
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- 1999
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56. A vector for promoter trapping in Bacillus cereus
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Dunn, A. K. and Handelsman, J.
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- 1999
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57. Engineering the rhizosphere: expressing a bias
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O'Connell, K. P., Goodman, R. M., and Handelsman, J.
- Published
- 1996
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58. Rhizobium meliloti competitiveness and the alfalfa agglutinin
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Handelsman, J, Ugalde, R A, and Brill, W J
- Abstract
We have isolated two types of isolates having identical colony morphologies from stock cultures of two different Rhizobium meliloti strains. One isolate was agglutinated at a high-dilution titer (HA, highly agglutinable) of the alfalfa agglutinin and was sensitive to phage F20, and the other was agglutinated at a lower agglutinin titer (LA) and was sensitive to phage 16B. All LA isolates from the original slant produced nodules on alfalfa earlier than did HA strains from the original slant. When these HA and LA strains were mixed and used as the inoculum in both vermiculite and field soil in the laboratory, LA strains were always the predominant strains recovered from the nodules. LA strains were obtained from HA cells by selection for resistance to phage F20, and HA strains were obtained from LA cells by selection for resistance to phage 16B. All of the strains with the HA phenotype that were derived from LA strains by phage selection had the nodulation properties of the HA strains from the original slant. Two classes of strains with the LA phenotype were obtained from HA cells by phage selection. One was identical to the original LA strains from the slant, and the other had the nodulation properties of the HA strains. Thus, we have shown that some cell surface properties change the nodulation abilities of R. meliloti strains and, furthermore, that specific phages can be used to enrich for more competitive rhizobia.
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- 1984
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59. Role of galactosyltransferase activity in phage sensitivity and nodulation competitiveness of Rhizobium meliloti
- Author
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Ugalde, R A, Handelsman, J, and Brill, W J
- Abstract
A stock culture of Rhizobium meliloti 102F51 contains colonies of two distinct phenotypes (Handelsman et al., J. Bacteriol. 157:703-707, 1984); one colony type is agglutinated by high dilutions of the alfalfa agglutinin, is sensitive to phage F20, and is resistant to phage 16B, and the other is agglutinated only by low dilutions of the alfalfa agglutinin, is resistant to phage F20, and is sensitive to phage 16B. Cells of the latter phenotype have an inner-membrane-bound galactosyltransferase activity that transfers galactose from UDP-galactose to a water-insoluble anionic polymer. This enzymatic activity is absent in cells of the first phenotype. All of the phage 16B-resistant mutants selected from a sensitive strain were agglutinated by high dilutions of the alfalfa agglutinin, were sensitive to phage F20, and lacked galactosyltransferase activity. The galactose-containing polymer prepared in vitro was immunologically cross-reactive with the cell surface.
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- 1986
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60. Mechanism of Inhibition of Human Testicular Steroidogenesis by Oral Ketoconazole∗
- Author
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RAJFER, JACOB, primary, SIKKA, SURESH C., additional, RIVERA, FABIO, additional, and HANDELSMAN, J., additional
- Published
- 1986
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61. l'utilisation de fils conducteurs en aluminium
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Galand, J., primary, Marin, C., additional, Rémond, M., additional, Auber, R., additional, Schmeltz, J., additional, Handelsman, J., additional, Tretiakow, N., additional, and de Pémille, J., additional
- Published
- 1977
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62. Quantitative comparison of the laboratory and field competitiveness of Rhizobium leguminosarum biovar phaseoli
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Beattie, G A, primary, Clayton, M K, additional, and Handelsman, J, additional
- Published
- 1989
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63. Erwinia herbicola isolates from alfalfa plants may play a role in nodulation of alfalfa by Rhizobium meliloti
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Handelsman, J, primary and Brill, W J, additional
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- 1985
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64. THE SURGICAL TREATMENT AND THE PHYSIOPATHOLOGY OF COARCTATION OF THE AORTA
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Bing, R J, primary, Handelsman, J C, additional, Campbell, J A, additional, Griswold, H E, additional, and Blalock, Alfred, additional
- Published
- 1948
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65. Catheterization of the Coronary Sinus and the Middle Cardiac Vein in Man.
- Author
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Bing, R. J., primary, Vandam, L. D., additional, Gregoire, F., additional, Handelsman, J. C., additional, Goodale, W. T., additional, and Eckenhoff, J. E., additional
- Published
- 1947
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66. CHYLOUS CYSTS OF THE MESENTERY IN CHILDREN
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HANDELSMAN, J. C., primary and RAVITCH, MARK M., additional
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- 1954
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67. Diaphragmatic Herniation of the Pancreas
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Poppel, M. H., primary, Abrams, R. M., additional, Handelsman, J., additional, and Segal, A., additional
- Published
- 1954
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68. SENILE OSTEOPOROSIS: TREATMENT WITH A STEROID HORMONE COMBINATION
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HANDELSMAN, J. R., primary
- Published
- 1960
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69. BENIGN TERATOMA OF THE STOMACH IN AN INFANT
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HANDELSMAN, J. C., primary
- Published
- 1955
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70. The orthopoedic management of myelomeningocoele
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Handelsman, J. E., primary
- Published
- 1969
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71. BENIGN TERATOMA OF THE STOMACH IN AN INFANT
- Author
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HANDELSMAN, J. C., RIENHOFF, W. F., and WARD, GRANT E.
- Abstract
TERATOMAS arising from the stomach have been the subject of two published reports. Selman,1 in 1943, reported the case of an infant who was submitted to surgery at the age of 4 months because of an abdominal mass occupying the upper left quadrant. At operation, a fibrocystic mass 6 in. in diameter was disclosed, arising on a broad base from the anterior wall of the stomach. Removal of the mass and the portion of stomach wall from which it arose effected a cure. The tumor contained a variety of tissues, including skin and appendages, connective tissue, and colonic mucosa. It was a benign, complex teratoma. Selman's survey of the literature failed to disclose any previous case described by those interested in teratomas or benign gastric tumors.Large, Williams, and Neel encountered a similar tumor in a 7-month-old infant, in 1952.2 This child's hemoglobin was 4 gm. per 100
- Published
- 1955
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72. Chemical modulators of the innate immune response alter gypsy moth larval susceptibility to Bacillus thuringiensis
- Author
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Broderick Nichole A, Raffa Kenneth F, and Handelsman Jo
- Subjects
Microbiology ,QR1-502 - Abstract
Abstract Background The gut comprises an essential barrier that protects both invertebrate and vertebrate animals from invasion by microorganisms. Disruption of the balanced relationship between indigenous gut microbiota and their host can result in gut bacteria eliciting host responses similar to those caused by invasive pathogens. For example, ingestion of Bacillus thuringiensis by larvae of some species of susceptible Lepidoptera can result in normally benign enteric bacteria exerting pathogenic effects. Results We explored the potential role of the insect immune response in mortality caused by B. thuringiensis in conjunction with gut bacteria. Two lines of evidence support such a role. First, ingestion of B. thuringiensis by gypsy moth larvae led to the depletion of their hemocytes. Second, pharmacological agents that are known to modulate innate immune responses of invertebrates and vertebrates altered larval mortality induced by B. thuringiensis. Specifically, Gram-negative peptidoglycan pre-treated with lysozyme accelerated B. thuringiensis-induced killing of larvae previously made less susceptible due to treatment with antibiotics. Conversely, several inhibitors of the innate immune response (eicosanoid inhibitors and antioxidants) increased the host's survival time following ingestion of B. thuringiensis. Conclusions This study demonstrates that B. thuringiensis infection provokes changes in the cellular immune response of gypsy moth larvae. The effects of chemicals known to modulate the innate immune response of many invertebrates and vertebrates, including Lepidoptera, also indicate a role of this response in B. thuringiensis killing. Interactions among B. thuringiensis toxin, enteric bacteria, and aspects of the gypsy moth immune response may provide a novel model to decipher mechanisms of sepsis associated with bacteria of gut origin.
- Published
- 2010
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73. Contributions of gut bacteria to Bacillus thuringiensis-induced mortality vary across a range of Lepidoptera
- Author
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Holt Jonathan, McMahon Matthew D, Robinson Courtney J, Broderick Nichole A, Handelsman Jo, and Raffa Kenneth F
- Subjects
Biology (General) ,QH301-705.5 - Abstract
Abstract Background Gut microbiota contribute to the health of their hosts, and alterations in the composition of this microbiota can lead to disease. Previously, we demonstrated that indigenous gut bacteria were required for the insecticidal toxin of Bacillus thuringiensis to kill the gypsy moth, Lymantria dispar. B. thuringiensis and its associated insecticidal toxins are commonly used for the control of lepidopteran pests. A variety of factors associated with the insect host, B. thuringiensis strain, and environment affect the wide range of susceptibilities among Lepidoptera, but the interaction of gut bacteria with these factors is not understood. To assess the contribution of gut bacteria to B. thuringiensis susceptibility across a range of Lepidoptera we examined larval mortality of six species in the presence and absence of their indigenous gut bacteria. We then assessed the effect of feeding an enteric bacterium isolated from L. dispar on larval mortality following ingestion of B. thuringiensis toxin. Results Oral administration of antibiotics reduced larval mortality due to B. thuringiensis in five of six species tested. These included Vanessa cardui (L.), Manduca sexta (L.), Pieris rapae (L.) and Heliothis virescens (F.) treated with a formulation composed of B. thuringiensis cells and toxins (DiPel), and Lymantria dispar (L.) treated with a cell-free formulation of B. thuringiensis toxin (MVPII). Antibiotics eliminated populations of gut bacteria below detectable levels in each of the insects, with the exception of H. virescens, which did not have detectable gut bacteria prior to treatment. Oral administration of the Gram-negative Enterobacter sp. NAB3, an indigenous gut resident of L. dispar, restored larval mortality in all four of the species in which antibiotics both reduced susceptibility to B. thuringiensis and eliminated gut bacteria, but not in H. virescens. In contrast, ingestion of B. thuringiensis toxin (MVPII) following antibiotic treatment significantly increased mortality of Pectinophora gossypiella (Saunders), which was also the only species with detectable gut bacteria that lacked a Gram-negative component. Further, mortality of P. gossypiella larvae reared on diet amended with B. thuringiensis toxin and Enterobacter sp. NAB3 was generally faster than with B. thuringiensis toxin alone. Conclusion This study demonstrates that in some larval species, indigenous gut bacteria contribute to B. thuringiensis susceptibility. Moreover, the contribution of enteric bacteria to host mortality suggests that perturbations caused by toxin feeding induce otherwise benign gut bacteria to exert pathogenic effects. The interaction between B. thuringiensis and the gut microbiota of Lepidoptera may provide a useful model with which to identify the factors involved in such transitions.
- Published
- 2009
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74. A statistical toolbox for metagenomics: assessing functional diversity in microbial communities
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Handelsman Jo and Schloss Patrick D
- Subjects
Computer applications to medicine. Medical informatics ,R858-859.7 ,Biology (General) ,QH301-705.5 - Abstract
Abstract Background The 99% of bacteria in the environment that are recalcitrant to culturing have spurred the development of metagenomics, a culture-independent approach to sample and characterize microbial genomes. Massive datasets of metagenomic sequences have been accumulated, but analysis of these sequences has focused primarily on the descriptive comparison of the relative abundance of proteins that belong to specific functional categories. More robust statistical methods are needed to make inferences from metagenomic data. In this study, we developed and applied a suite of tools to describe and compare the richness, membership, and structure of microbial communities using peptide fragment sequences extracted from metagenomic sequence data. Results Application of these tools to acid mine drainage, soil, and whale fall metagenomic sequence collections revealed groups of peptide fragments with a relatively high abundance and no known function. When combined with analysis of 16S rRNA gene fragments from the same communities these tools enabled us to demonstrate that although there was no overlap in the types of 16S rRNA gene sequence observed, there was a core collection of operational protein families that was shared among the three environments. Conclusion The results of comparisons between the three habitats were surprising considering the relatively low overlap of membership and the distinctively different characteristics of the three habitats. These tools will facilitate the use of metagenomics to pursue statistically sound genome-based ecological analyses.
- Published
- 2008
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75. Catheterization of the Coronary Sinus and the Middle Cardiac Vein in Man.∗.
- Author
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Bing, R. J., Vandam, L. D., Gregoire, F., Handelsman, J. C., Goodale, W. T., and Eckenhoff, J. E.
- Published
- 1947
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76. GRAPHOLOGY.
- Author
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Handelsman, J. B.
- Subjects
GRAPHOLOGY ,WRITING ,CALLIGRAPHY ,SIGNS & symbols ,PICTURES ,COMMUNICATION - Abstract
This article focuses on the history of the use of pictures, symbols, and calligraphy as a means of communication. Primitive people in the pre-Biblical times used pictures as a means of communication. The Greeks reversed the direction of writing from left to right and also introduced the use of abbreviation. Calligraphy was standardized for several centuries.
- Published
- 1976
77. Supramalleolar wedge osteotomy: a method of correcting fixed equinus and associated deformities in children
- Author
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HANDELSMAN, J
- Published
- 2005
78. Molecular biological access to the chemistry of unknown soil microbes: a new frontier for natural products
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Handelsman, J
- Published
- 1998
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79. Proceedings: Aetiology of club foot.
- Author
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Handelsman, J E and Isaacs, H
- Published
- 1975
80. multimedia: Multimodal Mediation Analysis of Microbiome Data.
- Author
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Jiang H, Miao X, Thairu MW, Beebe M, Grupe DW, Davidson RJ, Handelsman J, and Sankaran K
- Abstract
Mediation analysis has emerged as a versatile tool for answering mechanistic questions in microbiome research because it provides a statistical framework for attributing treatment effects to alternative causal pathways. Using a series of linked regressions, this analysis quantifies how complementary data relate to one another and respond to treatments. Despite these advances, existing software's rigid assumptions often result in users viewing mediation analysis as a black box. We designed the multimedia R package to make advanced mediation analysis techniques accessible, ensuring that statistical components are interpretable and adaptable. The package provides a uniform interface to direct and indirect effect estimation, synthetic null hypothesis testing, bootstrap confidence interval construction, and sensitivity analysis, enabling experimentation with various mediator and outcome models while maintaining a simple overall workflow. The software includes modules for regularized linear, compositional, random forest, hierarchical, and hurdle modeling, making it well-suited to microbiome data. We illustrate the package through two case studies. The first re-analyzes a study of the microbiome and metabolome of Inflammatory Bowel Disease patients, uncovering potential mechanistic interactions between the microbiome and disease-associated metabolites, not found in the original study. The second analyzes new data about the influence of mindfulness practice on the microbiome. The mediation analysis highlights shifts in taxa previously associated with depression that cannot be explained indirectly by diet or sleep behaviors alone. A gallery of examples and further documentation can be found at https://go.wisc.edu/830110., Competing Interests: CONFLICTS OF INTEREST The authors declare no conflict of interest
- Published
- 2024
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81. Microbial community interactions on a chip.
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Juang DS, Wightman WE, Lozano GL, Juang TD, Barkal LJ, Yu J, Garavito MF, Hurley A, Venturelli OS, Handelsman J, and Beebe DJ
- Subjects
- Microbial Interactions physiology, Microbiota physiology, Anti-Bacterial Agents pharmacology, Vancomycin pharmacology, Rhizosphere, Gentamicins pharmacology, Lab-On-A-Chip Devices, Green Fluorescent Proteins metabolism, Bacillus cereus
- Abstract
Multispecies microbial communities drive most ecosystems on Earth. Chemical and biological interactions within these communities can affect the survival of individual members and the entire community. However, the prohibitively high number of possible interactions within a microbial community has made the characterization of factors that influence community development challenging. Here, we report a Microbial Community Interaction (µCI) device to advance the systematic study of chemical and biological interactions within a microbial community. The µCI creates a combinatorial landscape made up of an array of triangular wells interconnected with circular wells, which each contains either a different chemical or microbial strain, generating chemical gradients and revealing biological interactions. Bacillus cereus UW85 containing green fluorescent protein provided the "target" readout in the triangular wells, and antibiotics or microorganisms in adjacent circular wells are designated the "variables." The µCI device revealed that gentamicin and vancomycin are antagonistic to each other in inhibiting the target B. cereus UW85, displaying weaker inhibitory activity when used in combination than alone. We identified three-member communities constructed with isolates from the plant rhizosphere that increased or decreased the growth of B. cereus . The µCI device enables both strain-level and community-level insight. The scalable geometric design of the µCI device enables experiments with high combinatorial efficiency, thereby providing a simple, scalable platform for systematic interrogation of three-factor interactions that influence microorganisms in solitary or community life., Competing Interests: Competing interests statement:D.J.B. holds equity in Bellbrook Labs LLC, Tasso Inc., Salus Discovery LLC, Lynx Biosciences Inc., Stacks to the Future LLC, Onexio Biosystems LLC, Navitro Biosciences LLC, and Flambeau Diagnostics LLC. J.H. holds equity in Wacasa Pharmaceuticals, Inc. A patent application (US011185860B2) was filed through the Wisconsin Alumni Research Foundation for the device described in this work.
- Published
- 2024
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82. Co-zorbs: Motile, multispecies biofilms aid transport of diverse bacterial species.
- Author
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Magesh S, Schrope JH, Soto NM, Li C, Hurley AI, Huttenlocher A, Beebe DJ, and Handelsman J
- Abstract
Biofilms are three-dimensional structures containing one or more bacterial species embedded in extracellular polymeric substances. Although most biofilms are stationary, Flavobacterium johnsoniae forms a motile spherical biofilm called a zorb, which is propelled by its base cells and contains a polysaccharide core. Here, we report formation of spatially organized, motile, multispecies biofilms, designated "co-zorbs," that are distinguished by a core-shell structure. F. johnsoniae forms zorbs whose cells collect other bacterial species and transport them to the zorb core, forming a co-zorb. Live imaging revealed that co-zorbs also form in zebrafish, thereby demonstrating a new type of bacterial movement in vivo. This discovery opens new avenues for understanding community behaviors, the role of biofilms in bulk bacterial transport, and collective strategies for microbial success in various environments.
- Published
- 2024
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83. Skin-associated Corynebacterium amycolatum shares cobamides.
- Author
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Swaney MH, Henriquez N, Campbell T, Handelsman J, and Kalan LR
- Abstract
The underlying interactions that occur to maintain skin microbiome composition, function, and overall skin health are largely unknown. Often, these types of interactions are mediated by microbial metabolites. Cobamides, the vitamin B
12 family of cofactors, are essential for metabolism in many bacteria, but are only synthesized by a small fraction of prokaryotes, including certain skin-associated species. Therefore, we hypothesize that cobamide sharing mediates skin community dynamics. Preliminary work predicts that several skin-associated Corynebacterium species encode de novo cobamide biosynthesis and that their abundance is associated with skin microbiome diversity. Here, we show that commensal Corynebacterium amycolatum produces cobamides and that this synthesis can be tuned by cobalt limitation. To demonstrate cobamide sharing by C. amycolatum , we employed a co-culture assay using an E. coli cobamide auxotroph and show that C. amycolatum produces sufficient cobamides to support E. coli growth, both in liquid co-culture and when separated spatially on solid medium. We also generated a C. amycolatum non-cobamide-producing strain (cob- ) using UV mutagenesis that contains mutated cobamide biosynthesis genes cobK and cobO and confirm that disruption of cobamide biosynthesis abolishes support of E. coli growth through cobamide sharing. Our study provides a unique model to study metabolite sharing by microorganisms, which will be critical for understanding the fundamental interactions that occur within complex microbiomes and for developing approaches to target the human microbiota for health advances.- Published
- 2024
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84. Massively parallel mutant selection identifies genetic determinants of Pseudomonas aeruginosa colonization of Drosophila melanogaster .
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Miles J, Lozano GL, Rajendhran J, Stabb EV, Handelsman J, and Broderick NA
- Subjects
- Animals, Mice, Pseudomonas aeruginosa genetics, Genome, Bacterial, Virulence Factors genetics, Mammals genetics, Drosophila melanogaster genetics, Pseudomonas Infections genetics
- Abstract
Pseudomonas aeruginosa is recognized for its ability to colonize diverse habitats and cause disease in a variety of hosts, including plants, invertebrates, and mammals. Understanding how this bacterium is able to occupy wide-ranging niches is important for deciphering its ecology. We used transposon sequencing [Tn-Seq, also known as insertion sequencing (INSeq)] to identify genes in P. aeruginosa that contribute to fitness during the colonization of Drosophila melanogaster . Our results reveal a suite of critical factors, including those that contribute to polysaccharide production, DNA repair, metabolism, and respiration. Comparison of candidate genes with fitness determinants discovered in previous studies on P. aeruginosa identified several genes required for colonization and virulence determinants that are conserved across hosts and tissues. This analysis provides evidence for both the conservation of function of several genes across systems, as well as host-specific functions. These findings, which represent the first use of transposon sequencing of a gut pathogen in Drosophila , demonstrate the power of Tn-Seq in the fly model system and advance the existing knowledge of intestinal pathogenesis by D. melanogaster, revealing bacterial colonization determinants that contribute to a comprehensive portrait of P. aeruginosa lifestyles across habitats.IMPORTANCE Drosophila melanogaster is a powerful model for understanding host-pathogen interactions. Research with this system has yielded notable insights into mechanisms of host immunity and defense, many of which emerged from the analysis of bacterial mutants defective for well-characterized virulence factors. These foundational studies-and advances in high-throughput sequencing of transposon mutants-support unbiased screens of bacterial mutants in the fly. To investigate mechanisms of host-pathogen interplay and exploit the tractability of this model host, we used a high-throughput, genome-wide mutant analysis to find genes that enable the pathogen P. aeruginosa to colonize the fly. Our analysis reveals critical mediators of P. aeruginosa establishment in its host, some of which are required across fly and mouse systems. These findings demonstrate the utility of massively parallel mutant analysis and provide a platform for aligning the fly toolkit with comprehensive bacterial genomics., Competing Interests: The authors declare no conflict of interest.
- Published
- 2024
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85. Surface colonization by Flavobacterium johnsoniae promotes its survival in a model microbial community.
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Magesh S, Hurley AI, Nepper JF, Chevrette MG, Schrope JH, Li C, Beebe DJ, and Handelsman J
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- Humans, Sand, Flavobacterium genetics, Bacterial Proteins metabolism, Health Promotion, Microbiota
- Abstract
Flavobacterium johnsoniae is a ubiquitous soil and rhizosphere bacterium, but despite its abundance, the factors contributing to its success in communities are poorly understood. Using a model microbial community, T he H itchhikers o f the R hizosphere (THOR), we determined the effects of colonization on the fitness of F. johnsoniae in the community. Insertion sequencing, a massively parallel transposon mutant screen, on sterile sand identified 25 genes likely to be important for surface colonization. We constructed in-frame deletions of candidate genes predicted to be involved in cell membrane biogenesis, motility, signal transduction, and transport of amino acids and lipids. All mutants poorly colonized sand, glass, and polystyrene and produced less biofilm than the wild type, indicating the importance of the targeted genes in surface colonization. Eight of the nine colonization-defective mutants were also unable to form motile biofilms or zorbs, thereby suggesting that the affected genes play a role in group movement and linking stationary and motile biofilm formation genetically. Furthermore, we showed that the deletion of colonization genes in F. johnsoniae affected its behavior and survival in THOR on surfaces, suggesting that the same traits are required for success in a multispecies microbial community. Our results provide insight into the mechanisms of surface colonization by F. johnsoniae and form the basis for further understanding its ecology in the rhizosphere., Importance: Microbial communities direct key environmental processes through multispecies interactions. Understanding these interactions is vital for manipulating microbiomes to promote health in human, environmental, and agricultural systems. However, microbiome complexity can hinder our understanding of the underlying mechanisms in microbial community interactions. As a first step toward unraveling these interactions, we explored the role of surface colonization in microbial community interactions using T he H itchhikers O f the R hizosphere (THOR), a genetically tractable model community of three bacterial species, Flavobacterium johnsoniae , Pseudomonas koreensis , and Bacillus cereus . We identified F. johnsoniae genes important for surface colonization in solitary conditions and in the THOR community. Understanding the mechanisms that promote the success of bacteria in microbial communities brings us closer to targeted manipulations to achieve outcomes that benefit agriculture, the environment, and human health., Competing Interests: David J. Beebe holds equity in Bellbrook Labs LLC, Tasso Inc., Salus Discovery LLC, Lynx Biosciences Inc., Stacks to the Future LLC, Flambeau Diagnostics LLC, and Onexio Biosystems LLC. Jo Handelsman holds equity in Wacasa Inc. and Ascribe, Inc.
- Published
- 2024
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86. Massively parallel mutant selection identifies genetic determinants of Pseudomonas aeruginosa colonization of Drosophila melanogaster .
- Author
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Miles J, Lozano GL, Rajendhran J, Stabb EV, Handelsman J, and Broderick NA
- Abstract
Pseudomonas aeruginosa is recognized for its ability to colonize diverse habitats and cause disease in a variety of hosts, including plants, invertebrates, and mammals. Understanding how this bacterium is able to occupy wide-ranging niches is important for deciphering its ecology. We used transposon sequencing (Tn-Seq, also known as INSeq) to identify genes in P. aeruginosa that contribute to fitness during colonization of Drosophila melanogaster . Our results reveal a suite of critical factors, including those that contribute to polysaccharide production, DNA repair, metabolism, and respiration. Comparison of candidate genes with fitness determinants discovered in previous studies of P. aeruginosa identified several genes required for colonization and virulence determinants that are conserved across hosts and tissues. This analysis provides evidence for both the conservation of function of several genes across systems, as well as host-specific functions. These findings, which represent the first use of transposon sequencing of a gut pathogen in Drosophila , demonstrate the power of Tn-Seq in the fly model system and advance existing knowledge of intestinal pathogenesis by D. melanogaster , revealing bacterial colonization determinants that contribute to a comprehensive portrait of P . aeruginosa lifestyles across habitats.
- Published
- 2023
- Full Text
- View/download PDF
87. Hearing Loss in Children: Critical Medical Education Delivered as Massive Open Online Course (MOOC).
- Author
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Raven SA, Mott NM, Ibrahim NI, Cole CA, Munzer TG, Handelsman J, Vereb AF, Hashikawa AN, and Bohm LA
- Abstract
Purpose: Although early identification of pediatric hearing loss is crucial, a formal online training course has not been freely accessible to a global audience. In response, we created a novel course for health professionals worldwide., Method: Course development occurred from February 2019 to May 2020. Seventeen multidisciplinary experts provided video lectures and demonstrations, including a tour of ear anatomy, operating footage of cochlear implant insertion, and demonstrations of children undergoing hearing testing. Content also included steps for interpreting audiograms, an overview of early screening programs, interviews with Deaf/Hard of Hearing children, and an introduction to public health/educational infrastructure. The course was hosted on Coursera and launched on May 4, 2020., Results: The course was approved for 11.5 Continuing Medical Education (CME) and American Board of Pediatrics Maintenance of Certification (MOC)-Part 2 credits and spanned five modules comprised of 50 video learning segments: 1) Ear Anatomy, 2) Hearing Loss and Assessments, 3) Hearing Loss Diagnosis and Impact on Speech and Language Development, 4) Interventions for Hearing Loss, 5) Pediatric Vestibular System and Balance. Since its launch, 6,556 learners have enrolled and 1,540 have fully completed the course; Fifty percent were 25-34 years old, 62% were female, and 43% were from Asia. Average rating was 4.9/5 (n=180 reviews)., Conclusions: We created a freely accessible course for a global audience that provides a broad overview of pediatric hearing loss. Our multidisciplinary approach addresses an educational gap and can serve as a model for developing other online courses., Competing Interests: Dr. Mott was supported by a grant from the National Institutes of Health (NIH; 5 TL1 TR002242-05) during the conduct of this study.
- Published
- 2023
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88. A triangulated approach for understanding scientists' perceptions of public engagement with science.
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Calice MN, Bao L, Beets B, Brossard D, Scheufele DA, Feinstein NW, Heisler L, Tangen T, and Handelsman J
- Subjects
- Humans, Community Participation, Pandemics, COVID-19 epidemiology
- Abstract
Scientists are expected to engage with the public, especially when society faces challenges like the COVID-19 pandemic or climate change, but what public engagement means to scientists is not clear. We use a triangulated, mixed-methods approach combining survey and focus group data to gain insight into how pre-tenure and tenured scientists personally conceptualize public engagement. Our findings indicate that scientists' understanding of public engagement is similarly complex and diverse as the scholarly literature. While definitions and examples of one-way forms of engagement are the most salient for scientists, regardless of tenure status, scientists also believe public engagement with science includes two-way forms of engagement, such as citizen and community involvement in research. These findings suggest that clear definitions of public engagement are not necessarily required for its application but may be useful to guide scientists in their engagement efforts, so they align with what is expected of them.
- Published
- 2023
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89. Microbiome composition modulates secondary metabolism in a multispecies bacterial community.
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Chevrette MG, Thomas CS, Hurley A, Rosario-Meléndez N, Sankaran K, Tu Y, Hall A, Magesh S, and Handelsman J
- Subjects
- Anti-Bacterial Agents, Benzamides, Humans, Secondary Metabolism, Microbiota, Siderophores genetics, Siderophores metabolism
- Abstract
Bacterial secondary metabolites are a major source of antibiotics and other bioactive compounds. In microbial communities, these molecules can mediate interspecies interactions and responses to environmental change. Despite the importance of secondary metabolites in human health and microbial ecology, little is known about their roles and regulation in the context of multispecies communities. In a simplified model of the rhizosphere composed of Bacillus cereus , Flavobacterium johnsoniae , and Pseudomonas koreensis , we show that the dynamics of secondary metabolism depend on community species composition and interspecies interactions. Comparative metatranscriptomics and metametabolomics reveal that the abundance of transcripts of biosynthetic gene clusters (BGCs) and metabolomic molecular features differ between monocultures or dual cultures and a tripartite community. In both two- and three-member cocultures, P. koreensis modified expression of BGCs for zwittermicin, petrobactin, and other secondary metabolites in B. cereus and F. johnsoniae, whereas the BGC transcriptional response to the community in P. koreensis itself was minimal. Pairwise and tripartite cocultures with P. koreensis displayed unique molecular features that appear to be derivatives of lokisin, suggesting metabolic handoffs between species. Deleting the BGC for koreenceine, another P. koreensis metabolite, altered transcript and metabolite profiles across the community, including substantial up-regulation of the petrobactin and bacillibactin BGCs in B. cereus , suggesting that koreenceine represses siderophore production. Results from this model community show that bacterial BGC expression and chemical output depend on the identity and biosynthetic capacity of coculture partners, suggesting community composition and microbiome interactions may shape the regulation of secondary metabolism in nature.
- Published
- 2022
- Full Text
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90. THOR's Hammer: the Antibiotic Koreenceine Drives Gene Expression in a Model Microbial Community.
- Author
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Hurley A, Chevrette MG, Rosario-Meléndez N, and Handelsman J
- Subjects
- Gene Expression, Humans, Pseudomonas, Rhizosphere, Anti-Bacterial Agents pharmacology, Microbiota
- Abstract
Microbial interactions dictate the structure and function of microbiomes, but the complexity of natural communities can obscure the individual interactions. Model microbial communities constructed with genetically tractable strains known to interact in natural settings can untangle these networks and reveal underpinning mechanisms. Our model system, T he H itchhikers o f the R hizosphere (THOR), is composed of three species-Bacillus cereus, Flavobacterium johnsoniae, and Pseudomonas koreensis-that co-isolate from field-grown soybean roots. Comparative metatranscriptomics on THOR revealed global patterns of interspecies transcriptional regulation. When grown in pairs, each member of THOR exhibits unique signaling behavior. In the community setting, gene expression is dominated by pairwise interactions with Pseudomonas koreensis mediated either directly or indirectly by its production of the antibiotic koreenceine-the apparent "hammer" of THOR. In pairwise interactions, the koreenceine biosynthetic cluster is responsible for 85 and 22% of differentially regulated genes in F. johnsoniae and B. cereus, respectively. Although both deletion of the koreenceine locus and reduction of P. koreensis inoculum size increase F. johnsoniae populations, the transcriptional response of P. koreensis is only activated when it is a relative minority member at the beginning of coculture. The largest group of upregulated P. koreensis genes in response to F. johnsoniae are those without functional annotation, indicating that focusing on genes important for community interactions may offer a path toward functional assignments for unannotated genes. This study illustrates the power of comparative metatranscriptomics of microorganisms encountering increasing microbial complexity for understanding community signal integration, antibiotic responses, and interspecies communication. IMPORTANCE The diversity, ubiquity, and significance of microbial communities is clear. However, the predictable and reliable manipulation of microbiomes to impact human, environmental, and agricultural health remains a challenge. Effective remodeling of microbiomes will be enabled by understanding the interspecies interactions that govern community processes. The extreme complexity of most microbiomes has impeded characterization of the relevant interactions. Investigating the genetics and biochemistry of simplified, model microbiomes could unearth specific interactions and generate predictions about community-governing principles. Here, we use one such model community to quantify changes in gene expression of individual species as they encounter stimuli from one or more species, directly mapping combinatorial interspecies interactions. A surprising amount of gene expression is regulated by a single molecule, the antibiotic koreenceine, which appears to impact gene regulation across community networks.
- Published
- 2022
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91. Public engagement: Faculty lived experiences and perspectives underscore barriers and a changing culture in academia.
- Author
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Calice MN, Beets B, Bao L, Scheufele DA, Freiling I, Brossard D, Feinstein NW, Heisler L, Tangen T, and Handelsman J
- Subjects
- Financing, Organized, Humans, Organizations, United States, Universities, Faculty, Students
- Abstract
The idea of faculty engaging in meaningful dialogue with different publics instead of simply communicating their research to interested audiences has gradually morphed from a novel concept to a mainstay within most parts of the academy. Given the wide variety of public engagement modalities, it may be unsurprising that we still lack a comprehensive and granular understanding of factors that influence faculty willingness to engage with public audiences. Those nuances are not always captured by quantitative surveys that rely on pre-determined categories to assess scholars' willingness to engage. While closed-ended categories are useful to examine which factors influence the willingness to engage more than others, it is unlikely that pre-determined categories comprehensively represent the range of factors that undermine or encourage engagement, including perceptual influences, institutional barriers, and scholars' lived experiences. To gain insight into these individual perspectives and lived experiences, we conducted focus group discussions with faculty members at a large midwestern land-grant university in the United States. Our findings provide context to previous studies of public engagement and suggest four themes for future research. These themes affirm the persistence of institutional barriers to engaging with the public, particularly the expectations in the promotion process for tenure-track faculty. However, we also find a perception that junior faculty and graduate students are challenging the status quo by introducing a new wave of attention to public engagement. This finding suggests a "trickle-up" effect through junior faculty and graduate students expecting institutional support for public engagement. Our findings highlight the need to consider how both top-down factors such as institutional expectations and bottom-up factors such as graduate student interest shape faculty members' decisions to participate in public engagement activities., Competing Interests: The authors have declared that no competing interests exist.
- Published
- 2022
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92. Achieving STEM diversity: Fix the classrooms.
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Handelsman J, Elgin S, Estrada M, Hays S, Johnson T, Miller S, Mingo V, Shaffer C, and Williams J
- Abstract
Outdated teaching methods amount to discrimination.
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- 2022
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93. AJEDI in Science: Leveraging Instructor Communities to Create Antiracist Curricula.
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Miller S, Kerr JE, and Handelsman J
- Abstract
Gateway college science courses continue to exclude students from science, disproportionately discriminating against students of color. As the higher education system strives to reduce discrimination, we need a deliberate, iterative process to modify, supplement, or replace current modalities. By incorporating antiracist, just, equitable, diverse, and inclusive (AJEDI) principles throughout course design, instructors create learning environments that provide an antidote to historically oppressive systems. In this paper, we describe how a community of microbiology instructors who all teach Tiny Earth, a course-based undergraduate research experience, created and rapidly integrated antiracist content and pivoted to an online format in response to the social unrest and pandemic of 2020. The effort strengthened an existing teaching community of practice and produced collective change in classrooms across the nation. We provide a perspective on how instructor communities of practice can be leveraged to design and disseminate AJEDI curriculum., Competing Interests: The authors declare a conflict of interest. J.H. is part owner of Wacasa, Inc., a start-up dedicated to antibiotic discovery., (Copyright © 2022 Miller et al.)
- Published
- 2022
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94. GNPS Dashboard: collaborative exploration of mass spectrometry data in the web browser.
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Petras D, Phelan VV, Acharya D, Allen AE, Aron AT, Bandeira N, Bowen BP, Belle-Oudry D, Boecker S, Cummings DA Jr, Deutsch JM, Fahy E, Garg N, Gregor R, Handelsman J, Navarro-Hoyos M, Jarmusch AK, Jarmusch SA, Louie K, Maloney KN, Marty MT, Meijler MM, Mizrahi I, Neve RL, Northen TR, Molina-Santiago C, Panitchpakdi M, Pullman B, Puri AW, Schmid R, Subramaniam S, Thukral M, Vasquez-Castro F, Dorrestein PC, and Wang M
- Subjects
- Data Visualization, Mass Spectrometry, Software, Web Browser
- Published
- 2022
- Full Text
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95. Evolutionary Genome Mining for the Discovery and Engineering of Natural Product Biosynthesis.
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Chevrette MG, Selem-Mojica N, Aguilar C, Labby K, Bustos-Diaz ED, Handelsman J, and Barona-Gómez F
- Subjects
- Biosynthetic Pathways genetics, Genome, Genome, Bacterial, Genomics, Multigene Family, Biological Products chemistry
- Abstract
Genome mining has become an invaluable tool in natural products research to quickly identify and characterize the biosynthetic pathways that assemble secondary or specialized metabolites. Recently, evolutionary principles have been incorporated into genome mining strategies in an effort to better assess and prioritize novelty and understand their chemical diversification for engineering purposes. Here, we provide an introduction to the principles underlying evolutionary genome mining, including bioinformatic strategies and natural product biosynthetic databases. We introduce workflows for traditional genome mining, focusing on the popular pipeline antiSMASH, and methods to predict enzyme substrate specificity from genomic information. We then provide an in-depth discussion of evolutionary genome mining workflows, including EvoMining, CORASON, ARTS, and others, as adopted by our group for the discovery and prioritization of natural products biosynthetic gene clusters and their products., (© 2022. The Author(s), under exclusive license to Springer Science+Business Media, LLC, part of Springer Nature.)
- Published
- 2022
- Full Text
- View/download PDF
96. Needles in haystacks: reevaluating old paradigms for the discovery of bacterial secondary metabolites.
- Author
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Chevrette MG and Handelsman J
- Subjects
- Bacteria classification, Culture Media, Microbiota, Secondary Metabolism, Bacteria metabolism, Biological Products isolation & purification, Drug Discovery
- Abstract
Covering: up to 2021Natural products research is in the midst of a renaissance ushered in by a modern understanding of microbiology and the technological explosions of genomics and metabolomics. As the exploration of uncharted chemical space expands into high-throughput discovery campaigns, it has become increasingly clear how design elements influence success: (bio)geography, habitat, community dynamics, culturing/induction methods, screening methods, dereplication, and more. We explore critical considerations and assumptions in natural products discovery. We revisit previous estimates of chemical rediscovery and discuss their relatedness to study design and producer taxonomy. Through frequency analyses of biosynthetic gene clusters in publicly available genomic data, we highlight phylogenetic biases that influence rediscovery rates. Through selected examples of how study design at each level determines discovery outcomes, we discuss the challenges and opportunities for the future of high-throughput natural product discovery.
- Published
- 2021
- Full Text
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97. Social motility of biofilm-like microcolonies in a gliding bacterium.
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Li C, Hurley A, Hu W, Warrick JW, Lozano GL, Ayuso JM, Pan W, Handelsman J, and Beebe DJ
- Subjects
- Computer Simulation, Intravital Microscopy, Microfluidic Analytical Techniques, Plant Roots microbiology, Soil Microbiology, Time-Lapse Imaging, Biofilms, Flavobacterium physiology, Locomotion
- Abstract
Bacterial biofilms are aggregates of surface-associated cells embedded in an extracellular polysaccharide (EPS) matrix, and are typically stationary. Studies of bacterial collective movement have largely focused on swarming motility mediated by flagella or pili, in the absence of a biofilm. Here, we describe a unique mode of collective movement by a self-propelled, surface-associated biofilm-like multicellular structure. Flavobacterium johnsoniae cells, which move by gliding motility, self-assemble into spherical microcolonies with EPS cores when observed by an under-oil open microfluidic system. Small microcolonies merge, creating larger ones. Microscopic analysis and computer simulation indicate that microcolonies move by cells at the base of the structure, attached to the surface by one pole of the cell. Biochemical and mutant analyses show that an active process drives microcolony self-assembly and motility, which depend on the bacterial gliding apparatus. We hypothesize that this mode of collective bacterial movement on solid surfaces may play potential roles in biofilm dynamics, bacterial cargo transport, or microbial adaptation. However, whether this collective motility occurs on plant roots or soil particles, the native environment for F. johnsoniae, is unknown., (© 2021. The Author(s).)
- Published
- 2021
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98. How Dirt Could Help Save the Planet.
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Handelsman J
- Published
- 2021
- Full Text
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99. Tiny Earth: A Big Idea for STEM Education and Antibiotic Discovery.
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Hurley A, Chevrette MG, Acharya DD, Lozano GL, Garavito M, Heinritz J, Balderrama L, Beebe M, DenHartog ML, Corinaldi K, Engels R, Gutierrez A, Jona O, Putnam JHI, Rhodes B, Tsang T, Hernandez S, Bascom-Slack C, Blum JE, Price PA, Davis D, Klein J, Pultorak J, Sullivan NL, Mouncey NJ, Dorrestein PC, Miller S, Broderick NA, and Handelsman J
- Subjects
- Bacteria drug effects, Drug Discovery methods, Humans, Anti-Bacterial Agents, Drug Discovery education, Science education, Students
- Abstract
The world faces two seemingly unrelated challenges-a shortfall in the STEM workforce and increasing antibiotic resistance among bacterial pathogens. We address these two challenges with Tiny Earth, an undergraduate research course that excites students about science and creates a pipeline for antibiotic discovery., (Copyright © 2021 Hurley et al.)
- Published
- 2021
- Full Text
- View/download PDF
100. Chemically informed analyses of metabolomics mass spectrometry data with Qemistree.
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Tripathi A, Vázquez-Baeza Y, Gauglitz JM, Wang M, Dührkop K, Nothias-Esposito M, Acharya DD, Ernst M, van der Hooft JJJ, Zhu Q, McDonald D, Brejnrod AD, Gonzalez A, Handelsman J, Fleischauer M, Ludwig M, Böcker S, Nothias LF, Knight R, and Dorrestein PC
- Subjects
- Algorithms, Cluster Analysis, DNA chemistry, DNA Fingerprinting, Databases, Factual, Ecology, Food Analysis, Microbiota, Multivariate Analysis, Software, Tandem Mass Spectrometry, Workflow, Mass Spectrometry methods, Metabolomics
- Abstract
Untargeted mass spectrometry is employed to detect small molecules in complex biospecimens, generating data that are difficult to interpret. We developed Qemistree, a data exploration strategy based on the hierarchical organization of molecular fingerprints predicted from fragmentation spectra. Qemistree allows mass spectrometry data to be represented in the context of sample metadata and chemical ontologies. By expressing molecular relationships as a tree, we can apply ecological tools that are designed to analyze and visualize the relatedness of DNA sequences to metabolomics data. Here we demonstrate the use of tree-guided data exploration tools to compare metabolomics samples across different experimental conditions such as chromatographic shifts. Additionally, we leverage a tree representation to visualize chemical diversity in a heterogeneous collection of samples. The Qemistree software pipeline is freely available to the microbiome and metabolomics communities in the form of a QIIME2 plugin, and a global natural products social molecular networking workflow.
- Published
- 2021
- Full Text
- View/download PDF
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