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Umamaheswaran R, Dutta S, Khan MA, Bera M, Bera S, Kumar S. Identification of Chitin in Pliocene Fungi Using Py-GC × GC-TOFMS: Potential Implications for the Study of the Evolution of the Fungal Clade in Deep Time. Anal Chem 2022; 94:1958-1964. [PMID: 35037459 DOI: 10.1021/acs.analchem.1c03143] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Molecular dating estimates the origin of the fungal clade to the Pre-Cambrian. Yet, the oldest unambiguous fungal fossils date to the Ordovician and show remarkable diversity and organizational development. Recent studies have suggested that the dates for the emergence of fungi in the fossil record may be pushed back to the Proterozoic. However, the nonspecificity of the methods used in those studies necessitates the employment of a wider variety of analytical techniques that can independently verify the presence of chitin, a crucial prerequisite in the assignment of fungal affinity, particularly of putative fossils from the Pre-Cambrian. In this paper, we propose Py-GC × GC-TOFMS as an example of one such technique. We analyze fungal fossils from the Pliocene. We find that a suite of N-bearing compounds are present in the pyrolysis products of these fossils, from which we suggest that 3-acetamidopyrones and their methylated homologues can serve as specific pyrolytic markers for chitin. We discuss both how this technique can potentially be used to differentiate between biopolymers, including those similar to chitin such as peptidoglycan, and the potential implications of identifying such markers in fossils from deep time. We conclude that Py-GC × GC-TOFMS is a promising technique that can potentially be used alongside, or independent of, staining methods to detect the presence of chitin in fossils.
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Affiliation(s)
- Raman Umamaheswaran
- Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Suryendu Dutta
- Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India
| | - Mahasin Ali Khan
- Department of Botany, Siddho-Kanho-Birsa University, Puruliya 723149, India
| | - Meghma Bera
- Department of Botany, Vidyanagar College, Vidyanagar 743503, India
| | - Subir Bera
- Department of Botany, University of Calcutta, Kolkata 700019, India
| | - Sumit Kumar
- Department of Earth Sciences, Indian Institute of Technology Bombay, Mumbai 400076, India
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ElyC and Cyclic Enterobacterial Common Antigen Regulate Synthesis of Phosphoglyceride-Linked Enterobacterial Common Antigen. mBio 2021; 12:e0284621. [PMID: 34809459 PMCID: PMC8609368 DOI: 10.1128/mbio.02846-21] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The Gram-negative cell envelope is a complex structure delineating the cell from its environment. Recently, we found that enterobacterial common antigen (ECA) plays a role maintaining the outer membrane (OM) permeability barrier, which excludes toxic molecules including many antibiotics. ECA is a conserved carbohydrate found throughout Enterobacterales (e.g., Salmonella, Klebsiella, and Yersinia). There are two OM forms of ECA (phosphoglyceride-linked ECAPG and lipopolysaccharide-linked ECALPS) and one periplasmic form of ECA (cyclic ECACYC). ECAPG, found in the outer leaflet of the OM, consists of a linear ECA oligomer attached to phosphoglyceride through a phosphodiester linkage. The process through which ECAPG is produced from polymerized ECA is unknown. Therefore, we set out to identify genes interacting genetically with ECAPG biosynthesis in Escherichia coli K-12 using the competition between ECA and peptidoglycan biosynthesis. Through transposon-directed insertion sequencing, we identified an interaction between elyC and ECAPG biosynthesis. ElyC is an inner membrane protein previously shown to alter peptidoglycan biosynthesis rates. We found ΔelyC was lethal specifically in strains producing ECAPG without other ECA forms, suggesting ECAPG biosynthesis impairment or dysregulation. Further characterization suggested ElyC inhibits ECAPG synthesis in a posttranscriptional manner. Moreover, the full impact of ElyC on ECA levels requires the presence of ECACYC. Our data demonstrate ECACYC can regulate ECAPG synthesis in strains wild type for elyC. Overall, our data demonstrate ElyC and ECACYC act in a novel pathway that regulates the production of ECAPG, supporting a model in which ElyC provides feedback regulation of ECAPG production based on the periplasmic levels of ECACYC.
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Liu Y, Rollins AM, Levenson RM, Fereidouni F, Jenkins MW. Pocket MUSE: an affordable, versatile and high-performance fluorescence microscope using a smartphone. Commun Biol 2021; 4:334. [PMID: 33712728 PMCID: PMC7955119 DOI: 10.1038/s42003-021-01860-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2020] [Accepted: 02/02/2021] [Indexed: 12/11/2022] Open
Abstract
Smartphone microscopes can be useful tools for a broad range of imaging applications. This manuscript demonstrates the first practical implementation of Microscopy with Ultraviolet Surface Excitation (MUSE) in a compact smartphone microscope called Pocket MUSE, resulting in a remarkably effective design. Fabricated with parts from consumer electronics that are readily available at low cost, the small optical module attaches directly over the rear lens in a smartphone. It enables high-quality multichannel fluorescence microscopy with submicron resolution over a 10× equivalent field of view. In addition to the novel optical configuration, Pocket MUSE is compatible with a series of simple, portable, and user-friendly sample preparation strategies that can be directly implemented for various microscopy applications for point-of-care diagnostics, at-home health monitoring, plant biology, STEM education, environmental studies, etc.
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Affiliation(s)
- Yehe Liu
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Andrew M Rollins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA
| | - Richard M Levenson
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, CA, USA
| | - Farzad Fereidouni
- Department of Pathology and Laboratory Medicine, University of California Davis Medical Center, Sacramento, CA, USA
| | - Michael W Jenkins
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, OH, USA.
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA.
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Grigoryeva LS, Rehman S, White RC, Garnett JA, Cianciotto NP. Assay for Assessing Mucin Binding to Bacteria and Bacterial Proteins. Bio Protoc 2021; 11:e3933. [PMID: 33796607 DOI: 10.21769/bioprotoc.3933] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 12/09/2020] [Accepted: 12/14/2020] [Indexed: 11/02/2022] Open
Abstract
Legionella pneumophila, a Gram-negative bacterium and the causative agent of Legionnaires' disease, exports over 300 effector proteins/virulence factors, through its type II (T2SS) and type IV secretion systems (T4SS). One such T2SS virulence factor, ChiA, not only functions as a chitinase, but also as a novel mucinase, which we believe aids ChiA-dependent virulence during lung infection. Previously published protocols manipulated wild-type L. pneumophila strain 130b and its chiA mutant to express plasmid-encoded GFP. Similarly, earlier studies demonstrated that wheat germ agglutinin (WGA) can be fluorescently labeled and can bind to mucins. In the current protocol, GFP-labeled bacteria were incubated with type II and type III porcine stomach mucins, which were then labeled with TexasRed-tagged WGA and analyzed by flow-cytometry to measure the binding of bacteria to mucins in the presence or absence of endogenous ChiA. In addition, we analysed binding of purified ChiA to type II and type III porcine stomach mucins. This protocol couples both bacterial and direct protein binding to mucins and is the first to measure Gram-negative bacterial binding to mucins using WGA and flow-cytometric analysis. Graphic abstract: Strategy for assessing bacterial and protein binding to mucins.
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Affiliation(s)
- Lubov S Grigoryeva
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - Saima Rehman
- Centre for Host-Microbiome Interactions, Dental institute, King's College London, London, UK
| | - Richard C White
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
| | - James A Garnett
- Centre for Host-Microbiome Interactions, Dental institute, King's College London, London, UK
| | - Nicholas P Cianciotto
- Department of Microbiology and Immunology, Northwestern University Feinberg School of Medicine, Chicago, Illinois, USA
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Wu KY, Yang TX. A Novel Improved Gram Staining Method Based on the Capillary Tube. Pol J Microbiol 2021; 69:503-508. [PMID: 33574878 PMCID: PMC7812360 DOI: 10.33073/pjm-2020-043] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Revised: 08/11/2020] [Accepted: 09/02/2020] [Indexed: 11/06/2022] Open
Abstract
In this work, an exploratory study was conducted to examine Gram staining based on the capillary tube. Each Gram staining step for all bacterial strains tested was completed in capillary tubes. The results showed that different Gram staining morphologies were clearly visible in the capillary tubes. The results presented here demonstrated that the improved method could effectively distinguish between Gram-positive and Gram-negative bacteria, and only small volumes of reagents were required in this method. Collectively, this efficient method could rapidly and accurately identify the types of bacteria. Therefore, our findings could be used as a useful reference study for other staining methods.
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Affiliation(s)
- Kong-Yang Wu
- College of Life Science, Luoyang Normal University, Luoyang, China
| | - Tong-Xiang Yang
- College of Food and Bioengineering, Henan University of Science and Technology, Luoyang, China
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Exceptional Preservation of Fungi as H2-Bearing Fluid Inclusions in an Early Quaternary Paleo-Hydrothermal System at Cape Vani, Milos, Greece. MINERALS 2019. [DOI: 10.3390/min9120749] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The production of H2 in hydrothermal systems and subsurface settings is almost exclusively assumed a result of abiotic processes, particularly serpentinization of ultramafic rocks. The origin of H2 in environments not hosted in ultramafic rocks is, as a rule, unjustifiably linked to abiotic processes. Additionally, multiple microbiological processes among both prokaryotes and eukaryotes are known to involve H2-production, of which anaerobic fungi have been put forward as a potential source of H2 in subsurface environments, which is still unconfirmed. Here, we report fungal remains exceptionally preserved as fluid inclusions in hydrothermal quartz from feeder quartz-barite veins from the Cape Vani Fe-Ba-Mn ore on the Greek island of Milos. The inclusions possess filamentous or near-spheroidal morphologies interpreted as remains of fungal hyphae and spores, respectively. They were characterized by microthermometry, Raman spectroscopy, and staining of exposed inclusions with WGA-FITC under fluorescence microscopy. The spheroidal aqueous inclusions interpreted as fungal spores are unique by their coating of Mn-oxide birnessite, and gas phase H2. A biological origin of the H2 resulting from anaerobic fungal respiration is suggested. We propose that biologically produced H2 by micro-eukaryotes is an unrecognized source of H2 in hydrothermal systems that may support communities of H2-dependent prokaryotes.
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Nirmalananthan-Budau N, Rühle B, Geißler D, Moser M, Kläber C, Schäfer A, Resch-Genger U. Multimodal Cleavable Reporters for Quantifying Carboxy and Amino Groups on Organic and Inorganic Nanoparticles. Sci Rep 2019; 9:17577. [PMID: 31772213 PMCID: PMC6879591 DOI: 10.1038/s41598-019-53773-3] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Accepted: 10/25/2019] [Indexed: 02/06/2023] Open
Abstract
Organic and inorganic nanoparticles (NPs) are increasingly used as drug carriers, fluorescent sensors, and multimodal labels in the life and material sciences. These applications require knowledge of the chemical nature, total number of surface groups, and the number of groups accessible for subsequent coupling of e.g., antifouling ligands, targeting bioligands, or sensor molecules. To establish the concept of catch-and-release assays, cleavable probes were rationally designed from a quantitatively cleavable disulfide moiety and the optically detectable reporter 2-thiopyridone (2-TP). For quantifying surface groups on nanomaterials, first, a set of monodisperse carboxy-and amino-functionalized, 100 nm-sized polymer and silica NPs with different surface group densities was synthesized. Subsequently, the accessible functional groups (FGs) were quantified via optical spectroscopy of the cleaved off reporter after its release in solution. Method validation was done with inductively coupled plasma optical emission spectroscopy (ICP-OES) utilizing the sulfur atom of the cleavable probe. This comparison underlined the reliability and versatility of our probes, which can be used for surface group quantification on all types of transparent, scattering, absorbing and/or fluorescent particles. The correlation between the total and accessible number of FGs quantified by conductometric titration, qNMR, and with our cleavable probes, together with the comparison to results of conjugation studies with differently sized biomolecules reveal the potential of catch-and-release reporters for surface analysis. Our findings also underline the importance of quantifying particularly the accessible amount of FGs for many applications of NPs in the life sciences.
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Affiliation(s)
- Nithiya Nirmalananthan-Budau
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany
| | - Bastian Rühle
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
| | - Daniel Geißler
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
| | - Marko Moser
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany
| | - Christopher Kläber
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany
| | - Andreas Schäfer
- Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany
| | - Ute Resch-Genger
- Federal Institute for Materials Research and Testing (BAM), Richard-Willstätter-Str. 11, D-12489, Berlin, Germany.
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Pierron R, Gorfer M, Berger H, Jacques A, Sessitsch A, Strauss J, Compant S. Deciphering the Niches of Colonisation of Vitis vinifera L. by the Esca-Associated Fungus Phaeoacremonium aleophilum Using a gfp Marked Strain and Cutting Systems. PLoS One 2015; 10:e0126851. [PMID: 26061034 PMCID: PMC4464894 DOI: 10.1371/journal.pone.0126851] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2014] [Accepted: 04/08/2015] [Indexed: 11/23/2022] Open
Abstract
INTRODUCTION Esca disease has become a major threat for viticulture. Phaeoacremonium aleophilum is considered a pioneer of the esca complex pathosystem, but its colonisation behaviour inside plants remains poorly investigated. MATERIAL AND METHODS In this study, P. aleophilum::gfp7 colonisation was assessed six and twelve weeks post-inoculation in two different types of tissues: in the node and the internode of one year-old rooted cuttings of Cabernet Sauvignon. These processes of colonisation were compared with the colonisation by the wild-type strain using a non-specific lectin probe Alexa Fluor 488-WGA. RESULTS Data showed that six weeks post-inoculation of the internode, the fungus had colonised the inoculation point, the bark and xylem fibres. Bark, pith and xylem fibres were strongly colonised by the fungus twelve weeks post-inoculation and it can progress up to 8 mm from the point of inoculation using pith, bark and fibres. P. aleophilum was additionally detected in the lumen of xylem vessels in which tyloses blocked its progression. Different plant responses in specific tissues were additionally visualised. Inoculation of nodes led to restricted colonisation of P. aleophilum and this colonisation was associated with a plant response six weeks post-inoculation. The fungus was however detected in xylem vessels, bark and inside the pith twelve weeks post-inoculation. CONCLUSIONS These results demonstrate that P. aleophilum colonisation can vary according to the type of tissues and the type of spread using pith, bark and fibres. Woody tissues can respond to the injury and to the presence of this fungus, and xylem fibres play a key role in the early colonisation of the internode by P. aleophilum before the fungus can colonise xylem vessels.
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Affiliation(s)
- Romain Pierron
- Université de Toulouse, Equipe Vins Viticulture et Œnologie, Département des Sciences Agronomiques et Agroalimentaires, INP-EI Purpan, 75 voie du T.O.E.C. BP57611, Toulouse, France
- University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology, Tulln, Austria
| | - Markus Gorfer
- University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology, Tulln, Austria
- AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria
| | - Harald Berger
- AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria
| | - Alban Jacques
- Université de Toulouse, Equipe Vins Viticulture et Œnologie, Département des Sciences Agronomiques et Agroalimentaires, INP-EI Purpan, 75 voie du T.O.E.C. BP57611, Toulouse, France
| | - Angela Sessitsch
- AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria
| | - Joseph Strauss
- University of Natural Resources and Life Sciences, Department of Applied Genetics and Cell Biology, Tulln, Austria
- AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria
| | - Stéphane Compant
- AIT Austrian Institute of Technology GmbH, Health & Environment Department, Bioresources Unit, Tulln, Austria
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Zhang RY, Neu TR, Bellenberg S, Kuhlicke U, Sand W, Vera M. Use of lectins to in situ visualize glycoconjugates of extracellular polymeric substances in acidophilic archaeal biofilms. Microb Biotechnol 2014; 8:448-61. [PMID: 25488256 PMCID: PMC4408177 DOI: 10.1111/1751-7915.12188] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2014] [Accepted: 09/23/2014] [Indexed: 01/28/2023] Open
Abstract
Biofilm formation and the production of extracellular polymeric substances (EPS) by meso- and thermoacidophilic metal-oxidizing archaea on relevant substrates have been studied to a limited extent. In order to investigate glycoconjugates, a major part of the EPS, during biofilm formation/bioleaching by archaea on pyrite, a screening with 75 commercially available lectins by fluorescence lectin-binding analysis (FLBA) has been performed. Three representative archaeal species, Ferroplasma acidiphilum DSM 28986, Sulfolobus metallicus DSM 6482T and a novel isolate Acidianus sp. DSM 29099 were used. In addition, Acidianus sp. DSM 29099 biofilms on elemental sulfur were studied. The results of FLBA indicate (i) 22 lectins bound to archaeal biofilms on pyrite and 21 lectins were binding to Acidianus sp. DSM 29099 biofilms on elemental sulfur; (ii) major binding patterns, e.g. tightly bound EPS and loosely bound EPS, were detected on both substrates; (iii) the three archaeal species produced various EPS glycoconjugates on pyrite surfaces. Additionally, the substratum induced different EPS glycoconjugates and biofilm structures of cells of Acidianus sp. DSM 29099. Our data provide new insights into interactions between acidophilic archaea on relevant surfaces and also indicate that FLBA is a valuable tool for in situ investigations on archaeal biofilms.
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Affiliation(s)
- R Y Zhang
- Aquatische Biotechnologie, Biofilm Centre, Universität Duisburg - Essen, Universitätsstraße 5, 45141, Essen, Germany
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10
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Development of mass cytometry methods for bacterial discrimination. Anal Biochem 2011; 419:1-8. [DOI: 10.1016/j.ab.2011.07.035] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 07/22/2011] [Accepted: 07/28/2011] [Indexed: 11/19/2022]
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Thickness and surface density of extracellular polymers on Acidithiobacillus ferrooxidans. Appl Environ Microbiol 2007; 74:309-11. [PMID: 17981935 DOI: 10.1128/aem.01904-07] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
In vivo force microscopy measurements of Acidithiobacillus ferrooxidans revealed a repulsive force that was due to the presence of extracellular polymers on the bacterium's surface. Measured force-distance profiles were fit to steric force theory to estimate the density and thickness values of these exopolymers. The polymer densities were 3.4 x 10(16) to 7.1 x 10(16) molecules m(-2), and the equilibrium thickness was 29 nm.
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Brandl H, Bachofen R, Bischoff M. Generation of bioaerosols during manual mail unpacking and sorting. J Appl Microbiol 2006; 99:1099-107. [PMID: 16238740 DOI: 10.1111/j.1365-2672.2005.02700.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIMS The dynamics of bioaerosol generation in specific occupational environments where mail is manually unpacked and sorted was investigated. METHODS AND RESULTS Total number of airborne particles was determined in four different size classes (0.3-0.5, 0.5-1, 1-5 and >5 microm) by laser particle counting. Time dependent formation of bioaerosols was monitored by culturing methods and by specific staining followed by flow cytometry. Besides handling of regular mail, specially prepared letters ('spiked letters') were added to the mailbags to deliberately release powdered materials from letters and to simulate high impact loads. These letters contained various dry powdered biological and nonbiological materials such as milk powder, mushrooms, herbs and cat litter. Regarding the four size classes, particulate aerosol composition before mail handling was determined as 83.2 +/- 1.0, 15.2 +/- 0.7, 1.7 +/- 0.4 and 0.04 +/- 0.02%, respectively, whereas the composition changed during sorting to 66.8 +/- 7.9, 22.3 +/- 3.6, 10.4 +/- 4.0 and 0.57 +/- 0.27%, respectively. Mail processing resulted in an increase in culturable airborne bacteria and fungi. Maximum concentrations of bacteria reached 450 CFU m(-3), whereas 270 CFU of fungi were detected. CONCLUSIONS Indoor particle concentrations steadily increased during mail handling mostly associated with particles of diameters >1 microm. However, it was not possible to distinguish spiked letters from nonspiked by simple particle counting and CFU determinations. SIGNIFICANCE AND IMPACT OF STUDY The dynamics of bioaerosol generation have to be addressed when monitoring specific occupational environments (such as mail sorting facilities) regarding the occurrence of biological particles.
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Affiliation(s)
- H Brandl
- University of Zurich, Institute of Environmental Sciences, Zurich, Switzerland.
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Holm C, Jespersen L. A flow-cytometric gram-staining technique for milk-associated bacteria. Appl Environ Microbiol 2003; 69:2857-63. [PMID: 12732558 PMCID: PMC154518 DOI: 10.1128/aem.69.5.2857-2863.2003] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2002] [Accepted: 02/07/2003] [Indexed: 11/20/2022] Open
Abstract
A Gram-staining technique combining staining with two fluorescent stains, Oregon Green-conjugated wheat germ agglutinin (WGA) and hexidium iodide (HI) followed by flow-cytometric detection is described. WGA stains gram-positive bacteria while HI binds to the DNA of all bacteria after permeabilization by EDTA and incubation at 50 degrees C for 15 min. For WGA to bind to gram-positive bacteria, a 3 M potassium chloride solution was found to give the highest fluorescence intensity. A total of 12 strains representing some of the predominant bacterial species in bulk tank milk and mixtures of these were stained and analyzed by flow cytometry. Overall, the staining method showed a clear differentiation between gram-positive and gram-negative bacterial populations. For stationary-stage cultures of seven gram-positive bacteria and five gram-negative bacteria, an average of 99% of the cells were correctly interpreted. The method was only slightly influenced by the growth phase of the bacteria or conditions such as freezing at -18 degrees C for 24 h. For any of these conditions, an average of at least 95% of the cells were correctly interpreted. When stationary-stage cultures were stored at 5 degrees C for 14 days, an average of 86% of the cells were correctly interpreted. The Gram-staining technique was applied to the flow cytometry analysis of bulk tank milk inoculated with Staphylococcus aureus and Escherichia coli. These results demonstrate that the technique is suitable for analyzing milk samples without precultivation.
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Affiliation(s)
- Claus Holm
- Department of Veterinary and Milk Quality, Danish Dairy Board, DK-8000 Aarhus C, Denmark
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Böckelmann U, Manz W, Neu TR, Szewzyk U. Investigation of lotic microbial aggregates by a combined technique of fluorescent in situ hybridization and lectin-binding-analysis. J Microbiol Methods 2002; 49:75-87. [PMID: 11777585 DOI: 10.1016/s0167-7012(01)00354-2] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
A technique combining fluorescent in situ hybridization and lectin-binding-analysis (FISH-LBA) was developed and applied for the simultaneous detection of cellular components and glycoconjugates in lotic microbial aggregates (river snow). River snow aggregates were directly collected from the bulk water phase into coverslip chambers, in which the complete procedure including fixation, fluorescent in situ hybridization, lectin-binding and optical analysis by confocal laser scanning microscopy was performed. Neither autofluorescence originating from phyotosynthetic organisms nor inorganic particles did negatively interfere with the FISH-LBA technique. In river snow samples obtained from the river Elbe, Germany, distinct compartments of the river snow structure could be visualized with FITC-labelled lectins from Triticum vulgaris, Limulus polyphemus, Arachis hypogaea, Phaseolus vulgaris and Pseudomonas aeruginosa, binding to frequently occurring saccharide residues in the river snow matrix. The analysis could be performed on different levels of complexity. The combined technique visualized bacteria of different phylogenetic groups in the entire river snow structure as well as glycoconjugate components linked with various microcolonies. Different lectins stained slime layers and cell-envelopes of individual eukaryotic and prokaryotic cells. Consequently, application of the FISH-LBA technique allows the linkage between cellular and glycoconjugate identity in complex microbial communities.
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Affiliation(s)
- Uta Böckelmann
- Department of Microbial Ecology, Technical University, Sekretariat OE 5, Franklinstrasse 29, D-10587, Berlin, Germany.
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