151
|
Suzuki K, Iijima K, Asano S, Kuriyama H, Kitagawa Y. Induction of Viable but Nonculturable State in Beer Spoilage Lactic Acid Bacteria. JOURNAL OF THE INSTITUTE OF BREWING 2012. [DOI: 10.1002/j.2050-0416.2006.tb00734.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
|
152
|
van Overbeek LS, Wellington EMH, Egan S, Smalla K, Heuer H, Collard JM, Guillaume G, Karagouni AD, Nikolakopoulou TL, van Elsas JD. Prevalence of streptomycin-resistance genes in bacterial populations in European habitats. FEMS Microbiol Ecol 2012; 42:277-88. [PMID: 19709288 DOI: 10.1111/j.1574-6941.2002.tb01018.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
The prevalence of selected streptomycin (Sm)-resistance genes, i.e. aph (3''), aph (6)-1d, aph (6)-1c, ant (3'') and ant (6), was assessed in a range of pristine as well as polluted European habitats. These habitats included bulk and rhizosphere soils, manure from farm animals, activated sludge from wastewater treatment plants and seawater. The methods employed included assessments of the prevalence of the genes in habitat-extracted DNA by PCR, followed by hybridisation with specific probes, Sm-resistant culturable bacteria and exogenous isolation of plasmids carrying Sm-resistance determinants. The direct DNA-based analysis showed that aph (6)-1d genes were most prevalent in the habitats examined. The presence of the other four Sm-modifying genes was demonstrated in 58% of the tested habitats. A small fraction of the bacterial isolates (8%) did not possess any of the selected Sm-modifying genes. These isolates were primarily obtained from activated sludge and manure. The presence of Sm-modifying genes in the isolates often coincided with the presence of IncP plasmids. Exogenous isolation demonstrated the presence of plasmids of 40-200 kb in size harbouring Sm-resistance genes from all the environments tested. Most plasmids were shown to carry the ant (3'') gene, often in combination with other Sm-resistance genes, such as aph (3'') and aph (6)-1d. The most commonly found Sm-modifying gene on mobile genetic elements was ant (3''). Multiple Sm-resistance genes on the same genetic elements appeared to be the rule rather than the exception. It is concluded that Sm-resistance genes are widespread in the environmental habitats studied and often occur on mobile genetic elements and ant (3'') was most often encountered.
Collapse
Affiliation(s)
- Leo S van Overbeek
- Plant Research International B.V., P.O. Box 16, 6700 AA Wageningen, The Netherlands.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
153
|
Firmesse O, Morelli E, Vann S, Carpentier B. Monitoring of bacterial load in terms of culturable and non-culturable cells on new materials placed in a delicatessen serve over counter. Int J Food Microbiol 2012; 159:179-85. [DOI: 10.1016/j.ijfoodmicro.2012.09.005] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2012] [Revised: 09/07/2012] [Accepted: 09/11/2012] [Indexed: 11/16/2022]
|
154
|
|
155
|
Moon JM, Kim GY, Rhim H. A new idea for simple and rapid monitoring of gene expression: requirement of nucleotide sequences encoding an N-terminal HA tag in the T7 promoter-driven expression in E. coli. Biotechnol Lett 2012; 34:1841-6. [PMID: 22714269 DOI: 10.1007/s10529-012-0966-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2012] [Accepted: 05/22/2012] [Indexed: 11/27/2022]
Abstract
Mammalian expression vectors are used to overexpress genes of interest in mammalian cells. High temperature requirement protein A1 (HtrA1), used as a specific target, was expressed from the pHA-M-HtrA1 plasmid in HEK293T cells, inducing cell death. Expression of HtrA1 was driven by the pHA-M-HtrA1 mammalian expression vector in E. coli resulting in growth suppression of E. coli in an HtrA1 serine protease-dependent manner. By using various combinations of promoters, target genes and N-terminal tags, the T7 promoter and N-terminal HA tag in the mammalian expression vector were shown to be responsible for expression of target genes in E. coli. Thus the pHA-M-HtrA1 plasmid can be used as a novel, rapid pre-test system for expression and cytotoxicity of the specific target gene in E. coli before assessing its functions in mammalian cells.
Collapse
Affiliation(s)
- Jeong-Mi Moon
- Department of Medical Life Sciences, College of Medicine, The Catholic University of Korea, 222 Banpo-daero, Seocho-gu, Seoul 137-701, Korea
| | | | | |
Collapse
|
156
|
Tashyreva D, Elster J. Production of Dormant Stages and Stress Resistance of Polar Cyanobacteria. ACTA ACUST UNITED AC 2012. [DOI: 10.1007/978-94-007-4966-5_21] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
|
157
|
Kryazhevskikh NA, Demkina EV, Manucharova NA, Soina VS, Gal’chenko VF, El’-Registan GI. Reactivation of dormant and nonculturable bacterial forms from paleosoils and subsoil permafrost. Microbiology (Reading) 2012. [DOI: 10.1134/s0026261712040108] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
158
|
Abstract
Cholera is an acute, secretory diarrhoea caused by infection with Vibrio cholerae of the O1 or O139 serogroup. It is endemic in more than 50 countries and also causes large epidemics. Since 1817, seven cholera pandemics have spread from Asia to much of the world. The seventh pandemic began in 1961 and affects 3-5 million people each year, killing 120,000. Although mild cholera can be indistinguishable from other diarrhoeal illnesses, the presentation of severe cholera is distinct, with pronounced diarrhoeal purging. Management of patients with cholera involves aggressive fluid replacement; effective therapy can decrease mortality from more than 50% to less than 0·2%. Antibiotic treatment decreases volume and duration of diarrhoea by 50% and is recommended for patients with moderate to severe dehydration. Prevention of cholera depends on access to safe water and sanitation. Two oral cholera vaccines are available and the most effective use of these in integrated prevention programmes is being actively assessed.
Collapse
Affiliation(s)
- Jason B Harris
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Pediatrics, Harvard Medical School, Boston, MA, USA
| | - Regina C LaRocque
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA
| | - Firdausi Qadri
- International Centre for Diarrhoeal Disease Research, Dhaka, Bangladesh
| | - Edward T Ryan
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Department of Immunology and Infectious Diseases, Harvard School of Public Health, Boston, MA
| | - Stephen B Calderwood
- Division of Infectious Diseases, Massachusetts General Hospital, Boston, MA, USA; Department of Medicine, Harvard Medical School, Boston, MA, USA; Department of Microbiology and Immunobiology, Harvard Medical School, Boston, MA, USA.
| |
Collapse
|
159
|
Guélon T, Mathias JD, Deffuant G. Influence of spatial structure on effective nutrient diffusion in bacterial biofilms. J Biol Phys 2012; 38:573-88. [PMID: 24615220 DOI: 10.1007/s10867-012-9272-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2012] [Accepted: 05/14/2012] [Indexed: 11/29/2022] Open
Abstract
The main contribution of this paper is to use homogenization techniques to compute diffusion coefficients from experimental images of microbial biofilms. Our approach requires the analysis of several experimental spatial structures of biofilms in order to derive from them a Representative Volume Element (RVE). Then, we apply a suitable numerical procedure to the RVE to derive the diffusion coefficients. We show that diffusion coefficients significantly vary with the biofilm structure. These results suggest that microbial biofilm structures can favour nutrient access in some cases.
Collapse
Affiliation(s)
- Thomas Guélon
- Irstea - LISC (Laboratoire d'Ingénierie des Systèmes Complexes) 24, avenue des Landais, BP 50 085-63 172, Aubière Cedex 1, France,
| | | | | |
Collapse
|
160
|
Huff K, Aroonnual A, Littlejohn AEF, Rajwa B, Bae E, Banada PP, Patsekin V, Hirleman ED, Robinson JP, Richards GP, Bhunia AK. Light-scattering sensor for real-time identification of Vibrio parahaemolyticus, Vibrio vulnificus and Vibrio cholerae colonies on solid agar plate. Microb Biotechnol 2012; 5:607-20. [PMID: 22613192 PMCID: PMC3815873 DOI: 10.1111/j.1751-7915.2012.00349.x] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2010] [Accepted: 04/11/2012] [Indexed: 12/17/2022] Open
Abstract
The three most common pathogenic species of Vibrio, Vibrio cholerae, Vibrio parahaemolyticus and Vibrio vulnificus, are of major concerns due to increased incidence of water‐ and seafood‐related outbreaks and illness worldwide. Current methods are lengthy and require biochemical and molecular confirmation. A novel label‐free forward light‐scattering sensor was developed to detect and identify colonies of these three pathogens in real time in the presence of other vibrios in food or water samples. Vibrio colonies grown on agar plates were illuminated by a 635 nm laser beam and scatter‐image signatures were acquired using a CCD (charge‐coupled device) camera in an automated BARDOT (BActerial Rapid Detection using Optical light‐scattering Technology) system. Although a limited number of Vibrio species was tested, each produced a unique light‐scattering signature that is consistent from colony to colony. Subsequently a pattern recognition system analysing the collected light‐scatter information provided classification in 1−2 min with an accuracy of 99%. The light‐scattering signatures were unaffected by subjecting the bacteria to physiological stressors: osmotic imbalance, acid, heat and recovery from a viable but non‐culturable state. Furthermore, employing a standard sample enrichment in alkaline peptone water for 6 h followed by plating on selective thiosulphate citrate bile salts sucrose agar at 30°C for ∼ 12 h, the light‐scattering sensor successfully detected V. cholerae, V. parahaemolyticus and V. vulnificus present in oyster or water samples in 18 h even in the presence of other vibrios or other bacteria, indicating the suitability of the sensor as a powerful screening tool for pathogens on agar plates.
Collapse
Affiliation(s)
- Karleigh Huff
- Molecular Food Microbiology Laboratory, Department of Food Science, Purdue University, West Lafayette, IN, USA
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
161
|
Fernandes CEG, Das A, Nath BN, Faria DG, Loka Bharathi PA. Mixed response in bacterial and biochemical variables to simulated sand mining in placer-rich beach sediments, Ratnagiri, West coast of India. ENVIRONMENTAL MONITORING AND ASSESSMENT 2012; 184:2677-2689. [PMID: 21713495 DOI: 10.1007/s10661-011-2143-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 05/25/2011] [Indexed: 05/31/2023]
Abstract
We investigated the influence on bacterial community and biochemical variables through mechanical disturbance of sediment-akin to small-scale mining in Kalbadevi beach, Ratnagiri, a placer-rich beach ecosystem which is a potential mining site. Changes were investigated by comparing three periods, namely phase I before disturbance, phase II just after disturbance, and phase III 24 h after disturbance as the bacterial generation time is ≤7 h. Cores from dune, berm, high-, mid-, and low-tide were examined for changes in distribution of total bacterial abundance, total direct viability (counts under aerobic and anaerobic conditions), culturability and biochemical parameters up to 40 cm depth. Results showed that bacterial abundance decreased by an order from 10(6) cells g(-1) sediment, while, viability reduced marginally. Culturability on different-strength nutrient broth increased by 155% during phase II. Changes in sedimentary proteins, carbohydrates, and lipids were marked at berm and dune and masked at other levels by tidal influence. Sedimentary ATP reduced drastically. During phase III, Pearson's correlation between these variables evolved from non-significant to significant level. Thus, simulated disturbance had a mixed effect on bacterial and biochemical variables of the sediments. It had a negative impact on bacterial abundance, viability and ATP but positive impact on culturability. Viability, culturability, and ATP could act as important indicators reflecting the disturbance in the system at short time intervals. Culturability, which improved by an order, could perhaps be a fraction that contributes to restoration of the system at bacterial level. This baseline information about the potential mining site could help in developing rational approach towards sustainable harnessing of resources with minimum damage to the ecosystem.
Collapse
Affiliation(s)
- Christabelle E G Fernandes
- Council of Scientific and Industrial Research, National Institute of Oceanography, Dona Paula, Goa, 403004, India
| | | | | | | | | |
Collapse
|
162
|
Morrow G, Tanguay RM. Small heat shock protein expression and functions during development. Int J Biochem Cell Biol 2012; 44:1613-21. [PMID: 22502646 DOI: 10.1016/j.biocel.2012.03.009] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2012] [Revised: 03/15/2012] [Accepted: 03/19/2012] [Indexed: 11/19/2022]
Abstract
The expression of small heat shock proteins is tightly regulated during development in multiple organisms. As housekeeping proteins, small heat shock proteins help protect cells from apoptosis, stabilize the cytoskeleton and contribute to proteostasis. Consistently, depletion of one small heat shock protein is usually not detrimental due to a certain level of redundancy between the functions of each small heat shock protein. However, while their stress-induced expression is regulated by heat shock factors, their constitutive expression is under the control of other specific transcription factors, suggesting the existence of very specialized functions. This review focuses on the expression patterns and functions of small heat shock proteins in various organisms during development. This article is part of a Directed Issue entitled: Small HSPs in physiology and pathology.
Collapse
Affiliation(s)
- Geneviève Morrow
- Laboratory of Cell and Developmental Genetics, Department of Molecular Biology, Medical Biochemistry and Pathology, Institut de Biologie Intégrative et des Systèmes and PROTEO, Université Laval, Québec, Canada G1V 0A6
| | | |
Collapse
|
163
|
Zelaya A, Vandervoort K, Brelles-Mariño G. Battling Bacterial Biofilms with Gas Discharge Plasma. PLASMA FOR BIO-DECONTAMINATION, MEDICINE AND FOOD SECURITY 2012. [DOI: 10.1007/978-94-007-2852-3_11] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
|
164
|
Chaves B, Han I, Dawson P, Northcutt J. Survival of artificially inoculated Escherichia coli and Salmonella Typhimurium on the surface of raw poultry products subjected to crust freezing. Poult Sci 2011; 90:2874-8. [DOI: 10.3382/ps.2011-01640] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
|
165
|
Banakar V, Constantin de Magny G, Jacobs J, Murtugudde R, Huq A, Wood RJ, Colwell RR. Temporal and spatial variability in the distribution of Vibrio vulnificus in the Chesapeake Bay: a hindcast study. ECOHEALTH 2011; 8:456-467. [PMID: 22302219 DOI: 10.1007/s10393-011-0736-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/09/2011] [Revised: 10/14/2011] [Accepted: 12/06/2011] [Indexed: 05/31/2023]
Abstract
Vibrio vulnificus, an estuarine bacterium, is the causative agent of seafood-related gastroenteritis, primary septicemia, and wound infections worldwide. It occurs as part of the normal microflora of coastal marine environments and can be isolated from water, sediment, and oysters. Hindcast prediction was undertaken to determine spatial and temporal variability in the likelihood of occurrence of V. vulnificus in surface waters of the Chesapeake Bay. Hindcast predictions were achieved by forcing a multivariate habitat suitability model with simulated sea surface temperature and salinity in the Bay for the period between 1991 and 2005 and the potential hotspots of occurrence of V. vulnificus in the Chesapeake Bay were identified. The likelihood of occurrence of V. vulnificus during high and low rainfall years was analyzed. From results of the study, it is concluded that hindcast prediction yields an improved understanding of environmental conditions associated with occurrence of V. vulnificus in the Chesapeake Bay.
Collapse
Affiliation(s)
- Vinita Banakar
- Earth System Science Interdisciplinary Center, University of Maryland, College Park, MD, USA
| | | | | | | | | | | | | |
Collapse
|
166
|
Tong Z, Tao R, Jiang W, Li J, Zhou L, Tian Y, Ni L. In vitro study of the properties of Streptococcus mutans in starvation conditions. Arch Oral Biol 2011; 56:1306-11. [DOI: 10.1016/j.archoralbio.2011.06.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2011] [Revised: 06/06/2011] [Accepted: 06/06/2011] [Indexed: 10/18/2022]
|
167
|
Puyen ZM, Villagrasa E, Maldonado J, Esteve I, Solé A. Viability and Biomass of Micrococcus luteus DE2008 at Different Salinity Concentrations Determined by Specific Fluorochromes and CLSM-Image Analysis. Curr Microbiol 2011; 64:75-80. [DOI: 10.1007/s00284-011-0033-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2011] [Accepted: 09/12/2011] [Indexed: 11/29/2022]
|
168
|
Bouvier T, Maurice CF. A single-cell analysis of virioplankton adsorption, infection, and intracellular abundance in different bacterioplankton physiologic categories. MICROBIAL ECOLOGY 2011; 62:669-678. [PMID: 21556883 DOI: 10.1007/s00248-011-9862-3] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Accepted: 04/22/2011] [Indexed: 05/30/2023]
Abstract
Culture studies of phage-host systems have shown that phage proliferation strongly depends on the physiological state of the host, but it is still unclear to what extent this holds true within aquatic ecosystems. We used a combination of flow sorting and electron microscopy to explore how the frequency of bacterial cells with attached viruses (FCAV), of visibly infected cells, and the number of intracellular viruses are distributed within five physiologic categories: cells with high (HNA) and low (LNA) nucleic acid content, with a compromised membrane, in division, and with an intact-looking morphology. FCAV was not different between the cellular physiologic categories, suggesting low influence of host physiology on viral adsorption. Infected cells were found within all the physiologic categories, besides the dividing cells, but showed different levels of new virion production, with the abundance of intracellular viruses ranked as follows: HNA > intact-looking cells > LNA > compromised membrane cells. These results favor the physiological control hypothesis of viral progeny production. The calculation of viral production rate of the HNA and LNA cells show that viral infection of HNA cells likely accounts for the majority of viral production. It also show that cells considered as less active can still act as resources for phages, although they contain much less intracellular phage particles.
Collapse
Affiliation(s)
- Thierry Bouvier
- Université Montpellier II UMR 5119 CNRS, IRD, IFREMER, CC 093, Place Eugène Bataillon, 34095 Montpellier cedex 5, France.
| | | |
Collapse
|
169
|
Schets F, van den Berg H, Marchese A, Garbom S, de Roda Husman A. Potentially human pathogenic vibrios in marine and fresh bathing waters related to environmental conditions and disease outcome. Int J Hyg Environ Health 2011; 214:399-406. [DOI: 10.1016/j.ijheh.2011.05.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2011] [Revised: 04/11/2011] [Accepted: 05/17/2011] [Indexed: 11/30/2022]
|
170
|
Arku B, Fanning S, Jordan K. Flow cytometry to assess biochemical pathways in heat-stressed Cronobacter spp. (formerly Enterobacter sakazakii). J Appl Microbiol 2011; 111:616-24. [PMID: 21672098 DOI: 10.1111/j.1365-2672.2011.05075.x] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
AIMS Using a flow cytometry (FC)-based approach in combination with four selected fluorescent probes, the biochemical pathway activated following the adaptation of Cronobacter spp. to lethal heat stress was investigated. This approach assessed the physiological changes induced in four strains of Cronobacter spp. METHODS AND RESULTS Using the commercially available live/dead viability assessment fluorescence probes, live, injured or dead bacterial cells were studied. Cellular respiration and membrane potential were evaluated using the dye-labelled probe 3,3'-dihexylocarbocyanine iodide, metabolic activity was evaluated using a fluorescein diacetate (FDA) probe, intracellular pH changes were measured using a carboxy-fluorescein diacetate succinimidyl ester probe, and reactive oxygen species were measured using a hydroethidine fluorescent probe. Adaptation to lethal heat stress induced physiological changes that potentially improve the survival of Cronobacter spp. CONCLUSIONS These data showed that in situ assessment of physiological behaviour of lethally stressed cells using multiparameter FC is a useful, rapid and sensitive tool to study and assess the viability and physiological state of Cronobacter cells. SIGNIFICANCE AND IMPACT OF THE STUDY This study shows that FC is a valuable tool in the study of physiological aspects of increased survival because of sublethal adaptation to heat.
Collapse
Affiliation(s)
- B Arku
- Teagasc, Food Research Centre, Moorepark, Fermoy, Cork, Ireland
| | | | | |
Collapse
|
171
|
Niwa R, Yoshida S, Furuya N, Tsuchiya K, Tsushima S. Method for simple and rapid enumeration of total epiphytic bacteria in the washing solution of rice plants. Can J Microbiol 2011; 57:62-7. [PMID: 21217798 DOI: 10.1139/w10-101] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The phyllosphere is one of the most common habitats for terrestrial bacteria. However, little is known about the populations of bacteria, including unculturable bacteria, that thrive on plant surfaces. Here, we developed a fluorescent nuclear staining technique to easily and rapidly observe and enumerate populations of total and living epiphytic bacteria, with particular emphasis on the concentration by centrifugation and fixation of the epiphytic bacteria. An investigation on the optimal conditions for centrifugation and fixation revealed that centrifugation at 20 400g for 2 min and fixation with 0.5% glutaraldehyde solution were the optimum conditions for observation of the bacteria. Using this technique, we assessed the populations of the total and living bacteria on the surface of rice plants. When epiphytic bacteria were recovered from rice seeds (Oryza sativa 'Koshihikari'), the number of total and living bacterial cells was 7.36 and 6.85 log₁₀·g⁻¹ (fresh mass) in the seed washing, respectively. In contrast, the numbers of total and living bacterial cells in the leaf sheath washings were 5.5-5.8 and 5.3-5.7 log₁₀·g⁻¹, respectively. Approximately 5%-30% of the total bacteria in the washing solution of rice plant were culturable. The usefulness of the enumeration method and the amount of bacteria on the plant surfaces are discussed.
Collapse
Affiliation(s)
- Rieko Niwa
- National Institute for Agro-Environmental Sciences, Tsukuba, Ibaraki, Japan
| | | | | | | | | |
Collapse
|
172
|
Thomas C, Gibson H, Hill DJ, Mabey M. Campylobacter epidemiology: an aquatic perspective. J Appl Microbiol 2011; 85 Suppl 1:168S-177S. [PMID: 21182706 DOI: 10.1111/j.1365-2672.1998.tb05296.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Members of the genus Campylobacter have established themselves as the most common human gastro-enteric pathogens throughout much of the developed world. The ubiquitous distribution of Campylobacter spp. in animal reservoirs and food products derived thereof make such vehicles primary risk factors in contracting campylobacteriosis. The contamination rates, identification of common pathogenic serotypes and extended survival of Campylobacter in surface waters illustrates the potential, but yet to be quantified, campylobacteriosis risk associated with untreated water. The existence and potential pathogenicity of viable but nonculturable forms of Campylobacter remains a contentious subject. Furthermore, the role of such forms in the epidemiology of Campylobacter related disease and their involvement in the large number of waterborne gastroenteritis outbreaks from which a disease agent cannot be isolated remains to be fully clarified. This article presents a survey of current perspectives with regard to the survival and epidemiology of Campylobacter spp. in natural water systems.
Collapse
Affiliation(s)
- C Thomas
- School of Applied Sciences, University of Wolverhampton, Wolverhampton, West Midlands, UK.
| | | | | | | |
Collapse
|
173
|
Enumeration of Vibrio parahaemolyticus in the viable but nonculturable state using direct plate counts and recognition of individual gene fluorescence in situ hybridization. J Microbiol Methods 2011; 85:114-8. [DOI: 10.1016/j.mimet.2011.02.006] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2011] [Accepted: 02/05/2011] [Indexed: 11/20/2022]
|
174
|
Abstract
Bacteria exhibit a wide variety of morphologies. This could simply be a consequence of an elaboration of bacterial cellular architecture akin to the famous decorative but not structurally essential Spandrels in the Basilica di San Marco in Venice that are a side-effect of an adaptation, rather than a direct product of natural selection. However, it is more likely that particular morphologies facilitate a specific function in cellular physiology. Two recent publications including one in this issue of Molecular Microbiology and another in Cell provide new insights into the molecular basis for the helical shape of the bacterium Helicobacter pylori and the role of this shape in pathogenesis. They identify a novel endopeptidase that is necessary to generate the helical shape by processing the peptidoglycan and report that catalytically inactive mutants lead to defects in colonization that appear to be independent of an effect on cellular motility. Here, we put these findings in the context of some of what is known about peptidoglycan and cell shape and suggest that the role of this endopeptidase in forming coccoid morphology may be critical for pathogenesis.
Collapse
Affiliation(s)
- Jonathan Dworkin
- Department of Microbiology and Immunology, College of Physicians and Surgeons, Columbia University, NewYork, NY 10032, USA.
| |
Collapse
|
175
|
Senoo K, Nishiyama M, Wada H, Matsumoto S. Differences in dynamics between indigenous and inoculated Sphingomonas paucimobilis strain SS86 in soils. FEMS Microbiol Ecol 2011. [DOI: 10.1111/j.1574-6941.1992.tb01766.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
|
176
|
Wolf PW, Oliver JD. Temperature effects on the viable but non-culturable state of Vibrio vulnificus. FEMS Microbiol Ecol 2011. [DOI: 10.1111/j.1574-6941.1992.tb01646.x] [Citation(s) in RCA: 62] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
177
|
Borbély G, Surányi G, Kós P. Stress responses of cyanobacteria and the pleiotropic effects of light deprivation. FEMS Microbiol Ecol 2011. [DOI: 10.1111/j.1574-6941.1990.tb01680.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
|
178
|
Swannell RPJ, Caplin R, Nedwell DB, Williamson FA. An investigation of hydroethidine as a fluorescent vital stain for prokaryotes. FEMS Microbiol Ecol 2011. [DOI: 10.1111/j.1574-6941.1992.tb01653.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
|
179
|
Abstract
The discovery of ammonia-oxidizing mesophilic and thermophilic Group I archaea changed the century-old paradigm that aerobic ammonia oxidation is solely mediated by two small clades of Beta- and Gammaproteobacteria. Group I archaea are extremely diverse and ubiquitous in marine and terrestrial environments, accounting for 20-30% of the microbial plankton in the global oceans. Recent studies indicated that many of these organisms carry putative ammonia monooxygenase genes and are more abundant than ammonia-oxidizing bacteria in most natural environments suggesting a potentially significant role in the nitrogen cycle. The isolation of Nitrosopumilus maritimus strain SCM1 provided the first direct evidence that Group I archaea indeed gain energy from ammonia oxidation. To characterize the physiology of this archaeal nitrifier, we developed a respirometry setup particularly suited for activity measurements in dilute microbial cultures with extremely low oxygen uptake rates. Here, we describe the setup and review the kinetic experiments conducted with N. maritimus and other nitrifying microorganisms. These experiments demonstrated that N. maritimus is adapted to grow on ammonia concentrations found in oligotrophic open ocean environments, far below the survival threshold of ammonia-oxidizing bacteria. The described setup and experimental procedures should facilitate physiological studies on other nitrifying archaea and oligotrophic microorganisms in general.
Collapse
Affiliation(s)
- Willm Martens-Habbena
- Department of Civil and Environmental Engineering, University of Washington, Seattle, Washington, USA
| | | |
Collapse
|
180
|
Markelova NY. Interaction of Bdellovibrio bacteriovorus with bacteria Campylobacter jejuni and Helicobacter pylori. Microbiology (Reading) 2010. [DOI: 10.1134/s0026261710060093] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
|
181
|
Zelaya AJ, Stough G, Rad N, Vandervoort K, Brelles-Mariño G. Pseudomonas aeruginosa Biofilm Inactivation: Decreased Cell Culturability, Adhesiveness to Surfaces, and Biofilm Thickness Upon High-Pressure Nonthermal Plasma Treatment. IEEE TRANSACTIONS ON PLASMA SCIENCE. IEEE NUCLEAR AND PLASMA SCIENCES SOCIETY 2010; 38:3398-3403. [PMID: 21544254 PMCID: PMC3085249 DOI: 10.1109/tps.2010.2082570] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
Bacterial biofilms are more resilient to standard killing methods than free-living bacteria. Pseudomonas aeruginosa PAO1 biofilms grown on borosilicate coupons were treated with gas-discharge plasma for various exposure times. Almost 100% of the cells were inactivated after a 5-min plasma exposure. Atomic force microscopy was used to image the biofilms and study their micromechanical properties. Results show that the adhesiveness to borosilicate and the thickness of the Pseudomonas biofilms are reduced upon plasma treatment.
Collapse
Affiliation(s)
- Anna J Zelaya
- Biological Sciences Department, California State Polytechnic University, Pomona, CA 91768 USA ( )
| | | | | | | | | |
Collapse
|
182
|
Microbiological characterization of a semi-enclosed sub-Antarctic environment: the Straits of Magellan. Polar Biol 2010. [DOI: 10.1007/s00300-010-0836-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
183
|
Predacious bacteria, Bdellovibrio with potential for biocontrol. Int J Hyg Environ Health 2010; 213:428-31. [DOI: 10.1016/j.ijheh.2010.08.004] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2010] [Revised: 08/08/2010] [Accepted: 08/18/2010] [Indexed: 11/20/2022]
|
184
|
Abstract
Bacteria can exist in metabolically inactive states that allow them to survive conditions that are not conducive for growth. Such dormant cells may sense when conditions have improved and re-initiate growth, lest they be outcompeted by their neighbours. Growing bacteria turn over and release large quantities of their cell walls into the environment. Drawing from recent work on the germination of Bacillus subtilis spores, we propose that many microorganisms exit dormancy in response to cell wall muropeptides.
Collapse
|
185
|
Role of planktonic and sessile extracellular metabolic byproducts on Pseudomonas aeruginosa and Escherichia coli intra and interspecies relationships. J Ind Microbiol Biotechnol 2010; 38:133-40. [PMID: 20811926 DOI: 10.1007/s10295-010-0838-y] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2010] [Accepted: 07/26/2010] [Indexed: 02/07/2023]
Abstract
Bacterial species are found primarily as residents of complex surface-associated communities, known as biofilms. Although these structures prevail in nature, bacteria still exist in planktonic lifestyle and differ from those in morphology, physiology, and metabolism. This study aimed to investigate the influence of physiological states of Pseudomonas aeruginosa and Escherichia coli in cell-to-cell interactions. Filtered supernatants obtained under planktonic and biofilm cultures of each single species were supplemented with tryptic soy broth (TSB) and used as the growth media (conditioned media) to planktonic and sessile growth of both single- and two-species cultures. Planktonic bacterial growth was examined through OD(640) measurement. One-day-old biofilms were evaluated in terms of biofilm biomass (CV), respiratory activity (XTT), and CFU number. Conditioned media obtained either in biofilm or in planktonic mode of life triggered a synergistic effect on planktonic growth, mainly for E. coli single cultures growing in P. aeruginosa supernatants. Biofilms grown in the presence of P. aeruginosa biofilms-derived metabolites presented less mass and activity. These events highlight that, when developed in biofilm, P. aeruginosa release signals or metabolites able to prejudice single and binary biofilm growth of others species and of their own species. However, products released by their planktonic counterparts did not impair biofilm growth or activity. E. coli, living as planktonic or sessile cultures, released signals and metabolites or removed un-beneficial compounds which promoted the growth and activity of all the species. Our findings revealed that inter and intraspecies behaviors depend on the involved bacteria and their adopted mode of life.
Collapse
|
186
|
Optimization of two immunofluorescent antibodies for the detection of Escherichia coli using immunofluorescent microscopy and flow cytometry. Curr Microbiol 2010; 62:402-8. [PMID: 20676677 DOI: 10.1007/s00284-010-9721-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/19/2009] [Accepted: 07/09/2010] [Indexed: 10/19/2022]
Abstract
Two commercially available fluorescein isothiocyanate (FITC) -conjugated anti-Escherichia coli antibodies, tested for immunofluorescence were assessed for their suitability in screening E. coli using flow cytometry. Staining efficacy was initially tested using immunofluorescent microscopy; and further optimization was carried out using flow cytometry. Initially, an acetone fixation step was utilized; however, it was determined statistically that the step could be omitted without impacting the assay and thus reduce the time involved. There was no statistical difference between the staining proficiency of the two antibodies employed. The percentage staining was quite low, approximately 10% for the two antibodies, which indicated that both were equally sensitive but ultimately, more specific antibodies are required for the detection of E. coli. Known proportions of target-E. coli (10⁵, 10⁶, and 10⁷ cells/ml) were mixed with large quantities of non-target bacteria; there was a significant correlation among all the antibodies at the different bacterial cell concentrations. Therefore, despite the low staining percentage achieved on the bacterial cultures, there is a representative and comparative level of staining occurring, between samples and between bacterial strains.
Collapse
|
187
|
Pérez LM, Alvarez BL, Codony F, Fittipaldi M, Adrados B, Peñuela G, Morató J. A new microtitre plate screening method for evaluating the viability of aerobic respiring bacteria in high surface biofilms. Lett Appl Microbiol 2010; 51:331-7. [PMID: 20681967 DOI: 10.1111/j.1472-765x.2010.02902.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
AIMS It is difficult to determine the effects of bactericidal compounds against bacteria in a biofilm because classical procedures for determining cell viability require several working days, multiple complicated steps and are frequently only applicable to cells in suspension. We attempt to develop a compact, inexpensive and versatile system to measure directly the extent of biofilm formation from water systems and to determine the viability of respiring bacteria in high surface biofilms. METHODS AND RESULTS It has been reported that the reduction of tetrazolium sodium salts, such as XTT (sodium 3,3'-[1-[(phenylamino)carbonyl]-3,4-tetrazolium]Bis(4-methoxy)-6-nitro)benzene sulfonic acid hydrate), during active bacterial metabolism can be incorporated into a colorimetric method for quantifying cell viability. XTT is reduced to a soluble formazan compound during bacterial aerobic metabolism such that the amount of formazan generated is proportional to the bacterial biomass. CONCLUSIONS We show here, for the first time, that this colorimetric approach can be used to determine the metabolic activity of adherent aerobic bacteria in a biofilm as a measure of cell viability. This technique has been used to estimate viability and proliferation of bacteria in suspension, but this is the first application to microbial communities in a real undisturbed biofilm. SIGNIFICANCE AND IMPACT OF THE STUDY This simple new system can be used to evaluate the complex biofilm community without separating the bacteria from their support. Thus, the results obtained by this practice may be more representative of the circumstances in a natural system, opening the possibility to multiple potential applications.
Collapse
Affiliation(s)
- L M Pérez
- Laboratori de Microbiologia Sanitaria i Mediambiental (MSM-Lab) & Aquasost - UNESCO Chair in Sustainability, Universitat Politècnica de Catalunya (UPC), Terrassa, Barcelona, Spain
| | | | | | | | | | | | | |
Collapse
|
188
|
Piñar G, Jimenez-Lopez C, Sterflinger K, Ettenauer J, Jroundi F, Fernandez-Vivas A, Gonzalez-Muñoz MT. Bacterial community dynamics during the application of a Myxococcus xanthus-inoculated culture medium used for consolidation of ornamental limestone. MICROBIAL ECOLOGY 2010; 60:15-28. [PMID: 20393845 PMCID: PMC2917555 DOI: 10.1007/s00248-010-9661-2] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/17/2009] [Accepted: 03/17/2010] [Indexed: 05/07/2023]
Abstract
In this study, we investigated under laboratory conditions the bacterial communities inhabiting quarry and decayed ornamental carbonate stones before and after the application of a Myxococcus xanthus-inoculated culture medium used for consolidation of the stones. The dynamics of the community structure and the prevalence of the inoculated bacterium, M. xanthus, were monitored during the time course of the consolidation treatment (30 days). For this purpose, we selected a molecular strategy combining fingerprinting by denaturing gradient gel electrophoresis (DGGE) with the screening of eubacterial 16S rDNA clone libraries by DGGE and sequencing. Quantification of the inoculated strain was performed by quantitative real-time PCR (qPCR) using M. xanthus-specific primers designed in this work. Results derived from DGGE and sequencing analysis showed that, irrespective of the origin of the stone,the same carbonatogenic microorganisms were activated by the application of a M. xanthus culture. Those microorganisms were Pseudomonas sp., Bacillus sp., and Brevibacillus sp. The monitoring of M. xanthus in the culture media of treated stones during the time course experiment showed disparate results depending on the applied technique. By culture-dependent methods, the detection of this bacterium was only possible in the first day of the treatment, showing the limitation of these conventional techniques. By PCR-DGGE analysis, M. xanthus was detected during the first 3-6 days of the experiment. At this time, the population of this bacterium in the culture media varied between 108-106 cells ml-1, as showed by qPCR analyses. Thereafter, DGGE analyses showed to be not suitable for the detection of M. xanthus in a mixed culture. Nevertheless, qPCR analysis using specific primers for M. xanthus showed to bea more sensitive technique for the detection of thisbacterium, revealing a population of 104 cells ml-1 in the culture media of both treated stones at the end of the consolidation treatment. The molecular strategy used in this study is proposed as an effective monitoring system to evaluate the impact of the application of a bacterially induced carbonate mineralization as restoration/conservation treatment for ornamental stones.
Collapse
Affiliation(s)
- Guadalupe Piñar
- Institute of Applied Microbiology, Department of Biotechnology, University of Natural Resources and Applied Life Sciences, Muthgasse 18, Vienna, Austria.
| | | | | | | | | | | | | |
Collapse
|
189
|
Modenutti B, Balseiro E, Corno G, Callieri C, Bertoni R, Caravati E. Ultraviolet Radiation Induces Filamentation in Bacterial Assemblages from North Andean Patagonian Lakes. Photochem Photobiol 2010; 86:871-81. [DOI: 10.1111/j.1751-1097.2010.00758.x] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
|
190
|
Linke S, Lenz J, Gemein S, Exner M, Gebel J. Detection of Helicobacter pylori in biofilms by real-time PCR. Int J Hyg Environ Health 2010; 213:176-82. [PMID: 20427237 DOI: 10.1016/j.ijheh.2010.03.006] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 03/23/2010] [Accepted: 03/25/2010] [Indexed: 12/18/2022]
Abstract
Helicobacter pylori is a cause of peptic ulcer disease and a causative agent of gastric cancer. Currently, a possible waterborne route of transmission or a possible survival in drinking water biofilms is discussed. H. pylori, like many other bacterial strains, has the ability to enter the viable but nonculturable state (vbnc) in case of unfavorable conditions. Therefore it is necessary to develop new analysis tools for vbnc bacteria. We established a fast and reliable method to detect H. pylori in drinking water biofilms by quantitative real-time PCR which makes it redundant to use difficult cultivation methods for nonculturable bacteria. With this method it was possible to identify water biofilms as a niche for H. pylori. The real-time PCR analysis targets the ureA subunit of the Helicobacter pylori urea gene which showed high specificity and sensitivity. The quantitative real-time PCR was used to detect H. pylori in biofilms of different age, unspiked and spiked with predetermined levels of cells. The drinking water biofilms were generated in a silicone-tube model. The DNA-sequences for probe and primers showed no cross-homologies to other related bacteria and it was possible to detect less than 10 genomic units of H. pylori. This novel method is a useful tool for a fast screening of drinking water biofilms for H. pylori. The results suggest that drinking water biofilms may act as a reservoir for H. pylori which raises new concerns about the role of biofilms as vectors for pathogens like Helicobacter pylori.
Collapse
Affiliation(s)
- S Linke
- Institute for Hygiene and Public Health, University of Bonn, Sigmund-Freud-Strasse 25, Klinikgelände 35, 53105 Bonn, Germany.
| | | | | | | | | |
Collapse
|
191
|
Wildeboer D, Amirat L, Price RG, Abuknesha RA. Rapid detection of Escherichia coli in water using a hand-held fluorescence detector. WATER RESEARCH 2010; 44:2621-2628. [PMID: 20153013 DOI: 10.1016/j.watres.2010.01.020] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/23/2009] [Revised: 01/08/2010] [Accepted: 01/23/2010] [Indexed: 05/28/2023]
Abstract
The quantification of pathogenic bacteria in an environmental or clinical sample commonly involves laboratory-based techniques and results are not obtained for 24-72 h after sampling. Enzymatic analysis of microbial activity in water and other environmental samples using fluorescent synthetic substrates are well-established and highly sensitive methods in addition to providing a measure of specificity towards indicative bacteria. The enzyme beta-d-glucuronidase (GUD) is a specific marker for Escherichia coli and 4-methylumbelliferone-beta-D-glucuronide (MUG) a sensitive substrate for determining the presence of E. coli in a sample. However, currently used procedures are laboratory-based and require bench-top fluorimeters for the measurement of fluorescence resulting from the enzyme-substrate reaction. Recent developments in electronic engineering have led to the miniaturisation of fluorescence detectors. We describe the use of a novel hand-held fluorimeter to directly analyse samples obtained from the River Thames for the presence of E. coli. The results obtained by the hand-held detector were compared with those obtained with an established fluorescent substrate assay and by quantifying microbial growth on a chromogenic medium. Both reference methods utilised filtration of water samples. The miniaturised fluorescence detector was used and incubation times reduced to 30 min making the detection system portable and rapid. The developed hand-held system reliably detected E. coli as low as 7 cfu/mL river water sample. Our study demonstrates that new hand-held fluorescence measurement technology can be applied to the rapid and convenient detection of bacteria in environmental samples. This enables rapid monitoring to be carried out on-site. The technique described is generic and it may, therefore, be used in conjunction with different fluorescent substrates which allows the assessment of various target microorganisms in biological samples.
Collapse
Affiliation(s)
- Dirk Wildeboer
- Analytical Sciences Research Group, Pharmaceutical Science Research Division, School of Biomedical & Health Sciences, King's College London, Franklin-Wilkins Building, 150 Stamford Street, London SE1 9NH, UK
| | | | | | | |
Collapse
|
192
|
Stabili L, Gravili C, Boero F, Tredici SM, Alifano P. Susceptibility to antibiotics of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host Aglaophenia octodonta (Cnidaria, Hydrozoa). MICROBIAL ECOLOGY 2010; 59:555-562. [PMID: 19888625 DOI: 10.1007/s00248-009-9605-x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/20/2009] [Accepted: 10/11/2009] [Indexed: 05/28/2023]
Abstract
Vibrio harveyi is the major causal organism of vibriosis, causing potential devastation to diverse ranges of marine invertebrates over a wide geographical area. These microorganisms, however, are phenotypically diverse, and many of the isolates are also resistant to multiple antibiotics. In a previous study, we described a previously unknown association between Vibrio sp. AO1, a luminous bacterium related to the species V. harveyi, and the benthic hydrozoan Aglaophenia octodonta. In this study, we analyzed the susceptibility to antibiotics (ampicillin, streptomycin, tetracycline, or co-trimoxazole = mix of sulfamethoxazole and trimetoprim) of Vibrio sp. AO1 growing in pure culture or in association with its hydroid host by using microcosm experiments. The results of minimum inhibitory concentration (MIC) experiments demonstrated that Vibrio sp. AO1 was highly resistant to ampicillin and streptomycin in pure culture. Nevertheless, these antibiotics, when used at sub-MIC values, significantly reduced the hydroid fluorescence. Co-trimoxazole showed the highest inhibitory effect on fluorescence of A. octodonta. However, in all treatments, the fluorescence was reduced after 48 h, but never disappeared completely around the folds along the hydrocaulus and at the base of the hydrothecae of A. octodonta when the antibiotic was used at concentration completely inhibiting growth in vitro. The apparent discrepancy between the MIC data and the fluorescence patterns may be due to either heterogeneity of the bacterial population in terms of antibiotic susceptibility or specific chemical-physical conditions of the hydroid microenvironment that may decrease the antibiotic susceptibility of the whole population. The latter hypothesis is supported by scanning electron microscope evidence for development of bacterial biofilm on the hydroid surface. On the basis of the results obtained, we infer that A. octodonta might behave as a reservoir of antibiotic multiresistant bacteria, increasing the risk of their transfer into aquaculture farms.
Collapse
Affiliation(s)
- Loredana Stabili
- University of Salento, Via Prov.le Lecce Monteroni, 73100 Lecce, Italy.
| | | | | | | | | |
Collapse
|
193
|
TAT-pathway-dependent lipoproteins as a niche-based adaptation in prokaryotes. J Mol Evol 2010; 70:359-70. [PMID: 20333370 DOI: 10.1007/s00239-010-9334-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2009] [Accepted: 03/03/2010] [Indexed: 10/19/2022]
Abstract
Bacterial lipoproteins, characterized by the N-terminal N-acyl S-diacylglyceryl Cysteine, are key membrane proteins in bacterial homeostasis. It is generally thought that during the modification lipoprotein precursors are translocated via the Sec-machinery in an unfolded state. The recent discovery of twin-arginine translocation (TAT) machinery, meant for exporting folded-proteins, and the presence of TAT-type signal sequences in co-factor-containing (hence already folded) lipoproteins, prompted us to investigate its role and significance in lipoprotein biosynthesis. We systematically analyzed 696 prokaryotic genomes using an algorithm based on DOLOP and TatP rules to predict TAT-pathway-dependent lipoprotein substrates. Occurrence of the deduced TAT-pathway-dependent lipoprotein substrates in relation to genome size, presence or absence of TAT machinery, and extent of its usage for lipoprotein export and habitat types revealed that unlike the host-obligates, the free-living prokaryotes in complex hostile environments (e.g., soil) depend more on TAT-exported lipoproteins. Functional classification of the predicted TAT-dependent lipoproteins revealed enrichment in hydrolases and oxido-reductases, which are fast-folding and co-factor-containing proteins. The role of the TAT pathway in the export of folded-lipoproteins and in niche-specific adaptation for survival has important implications not only in lipoprotein biosynthesis, but also for protein and metabolic engineering applications.
Collapse
|
194
|
Khan NH, Ahsan M, Taylor WD, Kogure K. Culturability and Survival of Marine, Freshwater and Clinical Pseudomonas aeruginosa. Microbes Environ 2010; 25:266-74. [DOI: 10.1264/jsme2.me09178] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Nurul H. Khan
- Marine Microbiology Laboratory, Marine Ecosystem Dynamics, Ocean Research Institute, The University of Tokyo
- Department of Biology, Faculty of Science, University of Waterloo
| | - Mahbuba Ahsan
- Marine Microbiology Laboratory, Marine Ecosystem Dynamics, Ocean Research Institute, The University of Tokyo
| | | | - Kazuhiro Kogure
- Marine Microbiology Laboratory, Marine Ecosystem Dynamics, Ocean Research Institute, The University of Tokyo
| |
Collapse
|
195
|
Cultivation-independent Assessment of Bacterial Viability. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 2010; 124:123-50. [DOI: 10.1007/10_2010_95] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
|
196
|
Soto W, Lostroh CP, Nishiguchi MK. Physiological Responses to Stress in the Vibrionaceae. CELLULAR ORIGIN, LIFE IN EXTREME HABITATS AND ASTROBIOLOGY 2010. [DOI: 10.1007/978-90-481-9449-0_20] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
197
|
Scott BA, Pepper IL. Water distribution systems as living ecosystems: impact on taste and odor. JOURNAL OF ENVIRONMENTAL SCIENCE AND HEALTH. PART A, TOXIC/HAZARDOUS SUBSTANCES & ENVIRONMENTAL ENGINEERING 2010; 45:890-900. [PMID: 20432105 DOI: 10.1080/10934521003709115] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Six waters from different U.S. cities with known diverse taste and odor (TO) evaluations were selected for additional microbial characterization. All waters were subjected to microbial and cultural analyses, and four of the waters were further analyzed by cloning and sequencing of community 16S rRNA. The purpose of the study was to evaluate water distribution systems as living ecosystems, and the impact of these ecosystems on TO. All waters had total bacterial counts of at least 10(3) per ml. The water with lowest TO ranking had 10(6) total counts per ml. Community DNA sequence analysis identified diverse bacterial communities representing five different phyla and over forty genera. Included in this diversity were heterotrophic and autotrophic species that were both aerobic or anaerobic. Additionally, waters with the lowest TO evaluations contained significant sulfide concentrations, as well as bacteria associated with both the oxidation and reduction of inorganic sulfur compounds. Low redox conditions could have resulted in the reduced sulfur compounds and concomitant TO related problems, and an increase in redox could help alleviate these problems. Overall, data show that water distribution systems contain living ecosystems that evolve based on specific environments within particular distribution systems that impact water TO.
Collapse
Affiliation(s)
- Beth A Scott
- Environmental Research Laboratory, The University of Arizona, Tucson, Arizona, USA
| | | |
Collapse
|
198
|
Shikuma NJ, Hadfield MG. Marine biofilms on submerged surfaces are a reservoir for Escherichia coli and Vibrio cholerae. BIOFOULING 2010; 26:39-46. [PMID: 20390555 DOI: 10.1080/08927010903282814] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
The enteric bacterium and potential human pathogen, Escherichia coli, is known to persist in tropical soils and coastal waters. Vibrio cholerae causes the disease cholera and inhabits marine environments including microbial films on submerged surfaces. The abundances of E. coli and V. cholerae were quantified in biofilm and water-column samples from three harbors in Honolulu, Hawai'i, which differ in their local and international ship traffic. E. coli and, in some cases V. cholerae, occurred in relatively high abundances in marine biofilms formed on abiotic surfaces, including the exterior hulls of ships. The community fingerprints of the biofilms and the water harboring these pathogens were further analyzed. The community compositions of biofilms from different locations were more similar to each other than to water-column communities from the same locations. These results suggest that biofilms are an overlooked reservoir and a source of dissemination for E. coli and V. cholerae.
Collapse
Affiliation(s)
- Nicholas J Shikuma
- Department of Microbiology and Environmental Toxicology, University of California, Santa Cruz, CA 95064, USA.
| | | |
Collapse
|
199
|
Thomas P, Soly TA. Endophytic bacteria associated with growing shoot tips of banana (Musa sp.) cv. Grand Naine and the affinity of endophytes to the host. MICROBIAL ECOLOGY 2009; 58:952-64. [PMID: 19633807 DOI: 10.1007/s00248-009-9559-z] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/15/2009] [Accepted: 06/20/2009] [Indexed: 05/02/2023]
Abstract
A cultivation-based assessment of endophytic bacteria present in deep-seated shoot tips of banana suckers was made with a view to generate information on the associated organisms, potential endophytic contaminants in tissue-cultured bananas and to assess if the endophytes shared a beneficial relationship with the host. Plating the tissue homogenate from the central core of suckers showed colony growth on nutrient agar from just 75% and 42% of the 12 stocks during May and November, respectively (average 58%; 6 x 10(3) colony-forming units per gram), yielding diverse organisms belonging to firmicutes (Bacillus, Brevibacillus, Paenibacillus, Virgibacillus, Staphylococcus spp.), actinobacteria (Cellulomonas, Micrococcus, Corynebacterium, Kocuria spp.), alpha-proteobacteria (Paracoccus sp.), and gamma-proteobacteria (Pseudomonas, Acinetobacter spp.). Each shoot tip showed one to three different organisms and no specific organism appeared common to different sucker tips. Tissue homogenate from shoot tips including the ones that did not yield culturable bacteria displayed abundant bacterial cells during microscopic examination suggesting that a high proportion of cells were in viable-but-nonculturable state, or their cultivation requirements were not met. Direct application of cultivation-independent approach to study endophytic bacterial community using bacterial 16S ribosomal RNA universal primers resulted in high interference from chloroplast and mitochondrial genome sequences. Dislodging the bacterial cells from shoot tips that did not show cultivable bacteria and incubating the tissue crush in dilute-nutrient broth led to the activation of four organisms (Klebsiella, Agrobacterium, Pseudacidovorax spp., and an unidentified isolate). The endophytic organisms in general showed better growth at 30-37 degrees C compared with 25 degrees C, and the growth of endophytes as well as pathogenic Erwinia carotovora were promoted with the supply of host tissue extract (HTE) while that of the isolates from nonplant sources were inhibited or unaffected by HTE, suggesting an affinity or dependence of the endophytes on the host and the prospect of an HTE-based assay for discriminating the nonendophytes from endophytes.
Collapse
Affiliation(s)
- Pious Thomas
- Division of Biotechnology, Indian Institute of Horticultural Research, Hessarghatta Lake, Bangalore, 560089, India.
| | | |
Collapse
|
200
|
Liu YJ, Zhang CM, Wang XC. Simultaneous detection of enteric bacteria from surface waters by QPCR in comparison with conventional bacterial indicators. ENVIRONMENTAL MONITORING AND ASSESSMENT 2009; 158:535-544. [PMID: 18931927 DOI: 10.1007/s10661-008-0602-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/01/2008] [Accepted: 09/29/2008] [Indexed: 05/26/2023]
Abstract
A rapid quantitative polymerase chain reaction (QPCR) method was developed for simultaneous detection of enteric bacteria from surface waters by utilizing a pair of universal primers which targeted four bacteria strains, namely Shigella dysenteriae, Vibrio cholerae, Salmonella typhimurium, and Escherichia coli. It was estimated that the QPCR method had a 94% confidence, and a detection limit as 2.7 E. coli cells per sample in undiluted DNA extracts. The QPCR method was applied for the bacteriological examination of several surface waters in the urban area of Xi'an, China and comparison was made with the conventional bacteria indicators determined by conventional membrane filter (MF) method. As a result, the calibrator cell equivalents (CCE) determined by QPCR was 2.2 to five times of the total coliform CFU, and the characteristics of the bacterial quality of different waters could be well presented by the QPCR results with a higher sensitivity. The coefficient of variation (CV) of data obtained by QPCR was smaller than that by traditional MF method, indicating a more stable analysis result. The QPCR method could thus be used as a supplement of the conventional culture method for more sensitive detection of pathogenic enteric bacteria from water.
Collapse
Affiliation(s)
- Y J Liu
- Key Laboratory of Northwest Water Resource, Ecology and Environment, Ministry of Education, Xi'an University of Architecture and Technology, Xi'an, 710055, China.
| | | | | |
Collapse
|