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Dalton HM, Viswanatha R, Brathwaite R, Zuno JS, Berman AR, Rushforth R, Mohr SE, Perrimon N, Chow CY. A genome-wide CRISPR screen identifies DPM1 as a modifier of DPAGT1 deficiency and ER stress. PLoS Genet 2022; 18:e1010430. [PMID: 36166480 PMCID: PMC9543880 DOI: 10.1371/journal.pgen.1010430] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2022] [Revised: 10/07/2022] [Accepted: 09/14/2022] [Indexed: 11/19/2022] Open
Abstract
Partial loss-of-function mutations in glycosylation pathways underlie a set of rare diseases called Congenital Disorders of Glycosylation (CDGs). In particular, DPAGT1-CDG is caused by mutations in the gene encoding the first step in N-glycosylation, DPAGT1, and this disorder currently lacks effective therapies. To identify potential therapeutic targets for DPAGT1-CDG, we performed CRISPR knockout screens in Drosophila cells for genes associated with better survival and glycoprotein levels under DPAGT1 inhibition. We identified hundreds of candidate genes that may be of therapeutic benefit. Intriguingly, inhibition of the mannosyltransferase Dpm1, or its downstream glycosylation pathways, could rescue two in vivo models of DPAGT1 inhibition and ER stress, even though impairment of these pathways alone usually causes CDGs. While both in vivo models ostensibly cause cellular stress (through DPAGT1 inhibition or a misfolded protein), we found a novel difference in fructose metabolism that may indicate glycolysis as a modulator of DPAGT1-CDG. Our results provide new therapeutic targets for DPAGT1-CDG, include the unique finding of Dpm1-related pathways rescuing DPAGT1 inhibition, and reveal a novel interaction between fructose metabolism and ER stress.
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Affiliation(s)
- Hans M. Dalton
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Raghuvir Viswanatha
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Roderick Brathwaite
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Jae Sophia Zuno
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Alexys R. Berman
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Rebekah Rushforth
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
| | - Stephanie E. Mohr
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
| | - Norbert Perrimon
- Department of Genetics, Blavatnik Institute, Harvard Medical School, Boston, Massachusetts, United States of America
- Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Clement Y. Chow
- Department of Human Genetics, University of Utah School of Medicine, Salt Lake City, Utah, United States of America
- * E-mail:
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Haghani A, Dalton HM, Safi N, Shirmohammadi F, Sioutas C, Morgan TE, Finch CE, Curran SP. CAENORHABDITIS ELEGANS AS A MODEL OF AIR POLLUTION TOXICITY DURING DEVELOPMENT AND LIFESPAN. Innov Aging 2019. [PMCID: PMC6844716 DOI: 10.1093/geroni/igz038.366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Air pollution (AirPoll) is among the leading human mortality risk factors and yet little is known about the molecular mechanisms of this global environmental toxin. Our recent studies using mouse models even showed genetic variation and sex can alter biological responses to air pollution. To expand genetic studies of AirPoll toxicity throughout the lifespan, we introduced Caenorhabditis elegans as a new AirPoll exposure model which has a short lifespan, high throughput capabilities and shared longevity pathways with mammals. Acute exposure of C. elegans to airborne nanosized AirPoll matter (nPM) caused similar gene expression changes to our prior findings in cell culture and mouse models. Initial C. elegans responses to nPM included antioxidant, inflammatory and Alzheimer homolog genes. The magnitude of changes was dependent on the developmental stage of the worms. Even short term exposure of C. elegans to nPM altered developmental and lifespan hormetic effects, with pathways that included skn-1/Nrf family antioxidant responses. We propose C. elegans as a new and complementary model for mouse and cultured cells to study AirPoll across the lifespan. Future chronic nPM exposure and high throughput genetic screening of C. elegans can identify other major regulators of the developmental and lifespan effects of air pollution. This work was supported by grants R01AG051521 (CEF); R21AG05020 (CEF); Cure Alzheimer’s Fund (CEF); R01GM109028 (SPC), F31AG051382 (HMD) and T32AG000037 (HMD), T32AG052374 (AH).
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Affiliation(s)
- Amin Haghani
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
| | - Hans M Dalton
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
| | - Nikoo Safi
- Center for Cancer Prevention and Translational Genomics at the Samuel Oschin Comprehensive Cancer Institute, Cedars-Sinai Medical Center, Los Angeles, California, United States
| | - Farimah Shirmohammadi
- Viterbi School of Engineering, University of Southern California, Los Angeles, California, United States
| | - Constantinos Sioutas
- Viterbi School of Engineering, University of Southern California, Los Angeles, California, United States
| | - Todd E Morgan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
| | - Caleb E Finch
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States
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Nhan JD, Turner CD, Anderson SM, Yen CA, Dalton HM, Cheesman HK, Ruter DL, Uma Naresh N, Haynes CM, Soukas AA, Pukkila-Worley R, Curran SP. Redirection of SKN-1 abates the negative metabolic outcomes of a perceived pathogen infection. Proc Natl Acad Sci U S A 2019; 116:22322-22330. [PMID: 31611372 PMCID: PMC6825279 DOI: 10.1073/pnas.1909666116] [Citation(s) in RCA: 46] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
Early host responses toward pathogens are essential for defense against infection. In Caenorhabditis elegans, the transcription factor, SKN-1, regulates cellular defenses during xenobiotic intoxication and bacterial infection. However, constitutive activation of SKN-1 results in pleiotropic outcomes, including a redistribution of somatic lipids to the germline, which impairs health and shortens lifespan. Here, we show that exposing C. elegans to Pseudomonas aeruginosa similarly drives the rapid depletion of somatic, but not germline, lipid stores. Modulating the epigenetic landscape refines SKN-1 activity away from innate immunity targets, which alleviates negative metabolic outcomes. Similarly, exposure to oxidative stress redirects SKN-1 activity away from pathogen response genes while restoring somatic lipid distribution. In addition, activating p38/MAPK signaling in the absence of pathogens, is sufficient to drive SKN-1-dependent loss of somatic fat. These data define a SKN-1- and p38-dependent axis for coordinating pathogen responses, lipid homeostasis, and survival and identify transcriptional redirection, rather than inactivation, as a mechanism for counteracting the pleiotropic consequences of aberrant transcriptional activity.
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Affiliation(s)
- James D Nhan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Christian D Turner
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Sarah M Anderson
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Chia-An Yen
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Hans M Dalton
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
| | - Hilary K Cheesman
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Dana L Ruter
- Biology Department, Integrative Program for Biological and Genome Sciences, University of North Carolina, Chapel Hill, NC 27599
| | - Nandhitha Uma Naresh
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Cole M Haynes
- Department of Molecular, Cell and Cancer Biology, University of Massachusetts Medical School, Worcester, MA 01655
| | - Alexander A Soukas
- Center for Human Genetic Research and Diabetes Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Read Pukkila-Worley
- Program in Innate Immunity, Division of Infectious Diseases and Immunology, University of Massachusetts Medical School, Worcester, MA 01655;
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089;
- Department of Molecular and Computation Biology, Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, CA 90089
- Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, CA 90089
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Haghani A, Dalton HM, Safi N, Shirmohammadi F, Sioutas C, Morgan TE, Finch CE, Curran SP. Air Pollution Alters Caenorhabditis elegans Development and Lifespan: Responses to Traffic-Related Nanoparticulate Matter. J Gerontol A Biol Sci Med Sci 2019; 74:1189-1197. [PMID: 30828708 PMCID: PMC6625599 DOI: 10.1093/gerona/glz063] [Citation(s) in RCA: 23] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2018] [Accepted: 02/06/2019] [Indexed: 11/22/2022] Open
Abstract
Air pollution is a heterogeneous environmental toxicant that impacts humans throughout their life. We introduce Caenorhabditis elegans as a valuable air pollution model with its short lifespan, medium-throughput capabilities, and highly conserved biological pathways that impact healthspan. We exposed developmental and adult life stages of C. elegans to airborne nano-sized particulate matter (nPM) produced by traffic emissions and measured biological and molecular endpoints that changed in response. Acute nPM did not cause lethality in C. elegans, but short-term exposure during larval stage 1 caused delayed development. Gene expression responses to nPM exposure overlapped with responses of mouse and cell culture models of nPM exposure in previous studies. We showed further that the skn-1/Nrf2 antioxidant response has a role in the development and hormetic effects of nPM. This study introduces the worm as a new resource and complementary model for mouse and cultured cell systems to study air pollution toxicity across the lifespan.
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Affiliation(s)
- Amin Haghani
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles
| | - Hans M Dalton
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles
| | - Nikoo Safi
- Department of Biomedical Sciences, Center for Bioinformatics and Genomics, Cedars-Sinai Medical Center, Los Angeles, California
| | | | | | - Todd E Morgan
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles
| | - Caleb E Finch
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles
| | - Sean P Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles,Address correspondence to: Sean P. Curran, PhD, Leonard Davis School of Gerontology, University of Southern California, 3715 McClintock Avenue, Suite 350, Los Angeles, CA 90089. E-mail:
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5
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Dalton HM, Curran SP. Hypodermal responses to protein synthesis inhibition induce systemic developmental arrest and AMPK-dependent survival in Caenorhabditis elegans. PLoS Genet 2018; 14:e1007520. [PMID: 30020921 PMCID: PMC6066256 DOI: 10.1371/journal.pgen.1007520] [Citation(s) in RCA: 26] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 07/30/2018] [Accepted: 06/27/2018] [Indexed: 01/08/2023] Open
Abstract
Across organisms, manipulation of biosynthetic capacity arrests development early in life, but can increase health- and lifespan post-developmentally. Here we demonstrate that this developmental arrest is not sickness but rather a regulated survival program responding to reduced cellular performance. We inhibited protein synthesis by reducing ribosome biogenesis (rps-11/RPS11 RNAi), translation initiation (ifg-1/EIF3G mutation and egl-45/EIF3A RNAi), or ribosome progression (cycloheximide treatment), all of which result in a specific arrest at larval stage 2 of C. elegans development. This quiescent state can last for weeks—beyond the normal C. elegans adult lifespan—and is reversible, as animals can resume reproduction and live a normal lifespan once released from the source of protein synthesis inhibition. The arrest state affords resistance to thermal, oxidative, and heavy metal stress exposure. In addition to cell-autonomous responses, reducing biosynthetic capacity only in the hypodermis was sufficient to drive organism-level developmental arrest and stress resistance phenotypes. Among the cell non-autonomous responses to protein synthesis inhibition is reduced pharyngeal pumping that is dependent upon AMPK-mediated signaling. The reduced pharyngeal pumping in response to protein synthesis inhibition is recapitulated by exposure to microbes that generate protein synthesis-inhibiting xenobiotics, which may mechanistically reduce ingestion of pathogen and toxin. These data define the existence of a transient arrest-survival state in response to protein synthesis inhibition and provide an evolutionary foundation for the conserved enhancement of healthy aging observed in post-developmental animals with reduced biosynthetic capacity. Protein synthesis is an essential cellular process, but post-developmental reduction of protein synthesis across multiple species leads to improved health- and lifespan. To better understand the physiological responses to impaired protein synthesis, we characterize a novel developmental arrest state that occurs when reducing protein synthesis during C. elegans development. Arrested animals have multiple survival-promoting phenotypes that are all dependent on the cellular energy sensor, AMP kinase. This survival response acts through the hypodermis and causes a reduction in pharyngeal pumping, indicating that the animal is responding to a perceived external threat, even in adults. Furthermore, exposing animals to pathogens, or xenobiotics they produce, can recapitulate these phenotypes, providing a potential evolutionary explanation for how a beneficial response in adults could evolve through the inhibition of an essential biological process such as protein synthesis.
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Affiliation(s)
- Hans M. Dalton
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
- Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, California, United States of America
| | - Sean P. Curran
- Leonard Davis School of Gerontology, University of Southern California, Los Angeles, California, United States of America
- Dornsife College of Letters, Arts, and Sciences, University of Southern California, Los Angeles, California, United States of America
- Norris Comprehensive Cancer Center, Keck School of Medicine, University of Southern California, Los Angeles, California, United States of America
- * E-mail:
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6
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Lynn DA, Dalton HM, Sowa JN, Wang MC, Soukas AA, Curran SP. Omega-3 and -6 fatty acids allocate somatic and germline lipids to ensure fitness during nutrient and oxidative stress in Caenorhabditis elegans. Proc Natl Acad Sci U S A 2015; 112:15378-83. [PMID: 26621724 PMCID: PMC4687584 DOI: 10.1073/pnas.1514012112] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Animals in nature are continually challenged by periods of feast and famine as resources inevitably fluctuate, and must allocate somatic reserves for reproduction to abate evolutionary pressures. We identify an age-dependent lipid homeostasis pathway in Caenorhabditis elegans that regulates the mobilization of lipids from the soma to the germline, which supports fecundity but at the cost of survival in nutrient-poor and oxidative stress environments. This trade-off is responsive to the levels of dietary carbohydrates and organismal oleic acid and is coupled to activation of the cytoprotective transcription factor SKN-1 in both laboratory-derived and natural isolates of C. elegans. The homeostatic balance of lipid stores between the somatic and germ cells is mediated by arachidonic acid (omega-6) and eicosapentaenoic acid (omega-3) precursors of eicosanoid signaling molecules. Our results describe a mechanism for resource reallocation within intact animals that influences reproductive fitness at the cost of somatic resilience.
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Affiliation(s)
- Dana A Lynn
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Hans M Dalton
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089
| | - Jessica N Sowa
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Meng C Wang
- Department of Molecular and Human Genetics, Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030
| | - Alexander A Soukas
- Center for Human Genetic Research and Diabetes Unit, Department of Medicine, Massachusetts General Hospital, Boston, MA 02114
| | - Sean P Curran
- Davis School of Gerontology, University of Southern California, Los Angeles, CA 90089; Dornsife College of Letters, Arts, and Sciences, Department of Molecular and Computational Biology, University of Southern California, Los Angeles, CA 90089;
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Kehrl JM, Sahaya K, Dalton HM, Charbeneau RA, Kohut KT, Gilbert K, Pelz MC, Parent J, Neubig RR. Gain-of-function mutation in Gnao1: a murine model of epileptiform encephalopathy (EIEE17)? Mamm Genome 2014; 25:202-10. [PMID: 24700286 PMCID: PMC4042023 DOI: 10.1007/s00335-014-9509-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2014] [Accepted: 03/11/2014] [Indexed: 12/13/2022]
Abstract
G protein-coupled receptors strongly modulate neuronal excitability but there has been little evidence for G protein mechanisms in genetic epilepsies. Recently, four patients with epileptic encephalopathy (EIEE17) were found to have mutations in GNAO1, the most abundant G protein in brain, but the mechanism of this effect is not known. The GNAO1 gene product, Gαo, negatively regulates neurotransmitter release. Here, we report a dominant murine model of Gnao1-related seizures and sudden death. We introduced a genomic gain-of-function knock-in mutation (Gnao1 (+/G184S)) that prevents Go turnoff by Regulators of G protein signaling proteins. This results in rare seizures, strain-dependent death between 15 and 40 weeks of age, and a markedly increased frequency of interictal epileptiform discharges. Mutants on a C57BL/6J background also have faster sensitization to pentylenetetrazol (PTZ) kindling. Both premature lethality and PTZ kindling effects are suppressed in the 129SvJ mouse strain. We have mapped a 129S-derived modifier locus on Chromosome 17 (within the region 41-70 MB) as a Modifer of G protein Seizures (Mogs1). Our mouse model suggests a novel gain-of-function mechanism for the newly defined subset of epileptic encephalopathy (EIEE17). Furthermore, it reveals a new epilepsy susceptibility modifier Mogs1 with implications for the complex genetics of human epilepsy as well as sudden death in epilepsy.
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Affiliation(s)
- Jason M. Kehrl
- />Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Kinshuk Sahaya
- />Department of Neurology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Hans M. Dalton
- />Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109 USA
| | | | - Kevin T. Kohut
- />Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Kristen Gilbert
- />Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Madeline C. Pelz
- />Department of Pharmacology, University of Michigan, Ann Arbor, MI 48109 USA
| | - Jack Parent
- />Department of Neurology, University of Michigan, Ann Arbor, MI 48109 USA
- />Ann Arbor Veterans Administration Healthcare System, Ann Arbor, MI 48105 USA
| | - Richard R. Neubig
- />Department of Pharmacology & Toxicology, Michigan State University, B440 Life Sciences, 1355 Bogue St, East Lansing, MI 48824 USA
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8
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Dalton HM, Stein J, March PE. A biological assay for detection of heterogeneities in the surface hydrophobicity of polymer coatings exposed to the marine environment. Biofouling 2000; 15:83-94. [PMID: 22115294 DOI: 10.1080/08927010009386300] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/31/2023]
Abstract
Minimally adhesive polymers are being developed as potential coatings for use in the marine environment. A 'bioprobe', the bacterium Psychrobacter sp. strain SW5, was employed to detect heterogeneities in substratum hydrophobicity at a micrometer level, rather than the millimeter level detected by traditional contact angle measurements. This novel assay was based on substratum-induced shifts in bacterial morphology and was used to demonstrate that characteristics of these surfaces can be evaluated for maintenance of parameters such as low surface free energy as well as temporal stability when immersed in water. Immersion of developmental substrata in artificial seawater for up to 90d prior to testing with the bioprobe potentially affects the stability of the designed characteristics of the polymers. It is proposed that the shifts in cell and biofilm morphology results from changes influencing the surface hydrophobicity of the polymers. An unpredicted outcome of this testing was the detection of modifications to coatings inferred by the addition of filler particles. Exposure of coatings to the natural microbial community of seawater revealed colonization characteristics that substantiate the results obtained by using the bioindicator.
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Affiliation(s)
- H M Dalton
- a School of Microbiology and Immunology , The University of New South Wales , Sydney , 2052 , Australia E-mail:
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9
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Abstract
Microbial adhesion to animate or inert surfaces is potentially mediated by nonspecific physical or specific ligand-receptor interactions. Growth and survival of the microbial community or biofilm then depends on adaptation to a series of changing environmental milieux. Within the realm of cell-cell interaction, recent advances suggest that flagella, fimbriae and other protein receptors are essential for bacterial attachment to surfaces. There has also been profound progress in the elucidation of genes and molecules necessary for bacterial attachments to surfaces and subsequent biofilm formation.
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Affiliation(s)
- H M Dalton
- School of Microbiology and Immunology, University of New South Wales Sydney, Australia.
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Poulsen LK, Dalton HM, Angles ML, Marshall KC, Molin S, Goodman AE. Simultaneous determination of gene expression and bacterial identity in single cells in defined mixtures of pure cultures. Appl Environ Microbiol 1997; 63:3698-702. [PMID: 9293021 PMCID: PMC168676 DOI: 10.1128/aem.63.9.3698-3702.1997] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
A protocol was developed to achieve the simultaneous determination of gene expression and bacterial identity at the level of single cells; a chromogenic beta-galactosidase activity assay was combined with in situ hybridization of fluorescently labelled oligonucleotide probes to rRNA. The method allows monitoring of gene expression and quantification of beta-galactosidase activity in single cells.
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Affiliation(s)
- L K Poulsen
- Department of Microbiology, Technical University of Denmark, Lyngby, Denmark
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Dalton HM, Poulsen LK, Halasz P, Angles ML, Goodman AE, Marshall KC. Substratum-induced morphological changes in a marine bacterium and their relevance to biofilm structure. J Bacteriol 1994; 176:6900-6. [PMID: 7961450 PMCID: PMC197059 DOI: 10.1128/jb.176.22.6900-6906.1994] [Citation(s) in RCA: 67] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023] Open
Abstract
The effects of surfaces on the physiology of bacteria adhering to surfaces or immobilized within biofilms are receiving more interest. A study of the effects of hydrophobic and hydrophilic substrata on the colonization behavior of a marine bacterium, SW5, revealed major differences in the morphology of SW5 on these surfaces. Using epifluorescence, scanning confocal laser, and on-line visualization (time-lapse video) microscopy, the organisms at hydrophobic surfaces were characterized by the formation of tightly packed biofilms, consisting of single and paired cells, whereas those at hydrophilic surfaces exhibited sparse colonization and the formation of chains more than 100 microns long, anchored at the surface by the terminal (colonizing) cell. The results are discussed in terms of the possible factors inducing the observed morphological differences and the significance of these differences in terms of biofilm structure and plasmid transfer when SW5 is the recipient organism.
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Affiliation(s)
- H M Dalton
- School of Microbiology and Immunology, University of New South Wales, Kensington, Australia
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