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Liu ZL, Chen X. Water-Content-Dependent Morphologies and Mechanical Properties of Bacillus subtilis Spores' Cortex Peptidoglycan. ACS Biomater Sci Eng 2022; 8:5094-5100. [PMID: 36442506 DOI: 10.1021/acsbiomaterials.2c01209] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Peptidoglycan (PG), bacterial spores' major structural component in their cortex layers, was recently found to regulate the spore's water content and deform in response to relative humidity (RH) changes. Here, we report that the cortex PG dominates the Bacillus subtilis spores' water-content-dependent morphological and mechanical properties. When exposed to an environment having RH varied between 10% and 90%, the spores and their cortex PG reversibly expand and contract by 30.7% and 43.2% in volume, which indicates that the cortex PG contributes to 67.3% of a spore's volume change. The spores' and cortex PG's significant volumetric changes also lead to changes in their Young's moduli from 5.7 and 9.0 GPa at 10% RH to 0.62 and 1.2 GPa at 90% RH, respectively. Interestingly, these significant changes in the spores' and cortex PG's morphological and mechanical properties are only caused by a minute amount of the cortex PG's water exchange that occupies 28.0% of the cortex PG's volume. The cortex PG's capability in sensing and responding to environmental RH and effectively changing its structures and properties could provide insight into spores' high desiccation resistance and dormancy mechanisms.
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Affiliation(s)
- Zhi-Lun Liu
- Advanced Science Research Center (ASRC), The City University of New York, 85 St. Nicholas Terrace, New York, New York10031, United States.,Department of Chemical Engineering, The City College of New York, 275 Convent Ave., New York, New York10031, United States
| | - Xi Chen
- Advanced Science Research Center (ASRC), The City University of New York, 85 St. Nicholas Terrace, New York, New York10031, United States.,Department of Chemical Engineering, The City College of New York, 275 Convent Ave., New York, New York10031, United States.,Ph.D. Program in Physics, The Graduate Center of the City University of New York, 365 Fifth Ave., New York, New York10016, United States.,Ph.D. Program in Chemistry, The Graduate Center of the City University of New York, 365 Fifth Ave., New York, New York10016, United States
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2
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Zheng L, Abhyankar W, Ouwerling N, Dekker HL, van Veen H, van der Wel NN, Roseboom W, de Koning LJ, Brul S, de Koster CG. Bacillus subtilis Spore Inner Membrane Proteome. J Proteome Res 2016; 15:585-94. [PMID: 26731423 DOI: 10.1021/acs.jproteome.5b00976] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
The endospore is the dormant form of Bacillus subtilis and many other Firmicutes. By sporulation, these spore formers can survive very harsh physical and chemical conditions. Yet, they need to go through germination to return to their growing form. The spore inner membrane (IM) has been shown to play an essential role in triggering the initiation of germination. In this study, we isolated the IM of bacterial spores, in parallel with the isolation of the membrane of vegetative cells. With the use of GeLC-MS/MS, over 900 proteins were identified from the B. subtilis spore IM preparations. By bioinformatics-based membrane protein predictions, ca. one-third could be predicted to be membrane-localized. A large number of unique proteins as well as proteins common to the two membrane proteomes were identified. In addition to previously known IM proteins, a number of IM proteins were newly identified, at least some of which are likely to provide new insights into IM physiology, unveiling proteins putatively involved in spore germination machinery and hence putative germination inhibition targets.
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Affiliation(s)
| | | | | | | | - Henk van Veen
- Electron Microscopy Centre Amsterdam, Department of Cell Biology and Histology, Academic Medical Center , 1105 AZ Amsterdam, The Netherlands
| | - Nicole N van der Wel
- Electron Microscopy Centre Amsterdam, Department of Cell Biology and Histology, Academic Medical Center , 1105 AZ Amsterdam, The Netherlands
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3
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Setlow P, Li L. Photochemistry and Photobiology of the Spore Photoproduct: A 50-Year Journey. Photochem Photobiol 2015; 91:1263-90. [PMID: 26265564 PMCID: PMC4631623 DOI: 10.1111/php.12506] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2015] [Accepted: 07/21/2015] [Indexed: 02/06/2023]
Abstract
Fifty years ago, a new thymine dimer was discovered as the dominant DNA photolesion in UV-irradiated bacterial spores [Donnellan, J. E. & Setlow R. B. (1965) Science, 149, 308-310], which was later named the spore photoproduct (SP). Formation of SP is due to the unique environment in the spore core that features low hydration levels favoring an A-DNA conformation, high levels of calcium dipicolinate that acts as a photosensitizer, and DNA saturation with small, acid-soluble proteins that alters DNA structure and reduces side reactions. In vitro studies reveal that any of these factors alone can promote SP formation; however, SP formation is usually accompanied by the production of other DNA photolesions. Therefore, the nearly exclusive SP formation in spores is due to the combined effects of these three factors. Spore photoproduct photoreaction is proved to occur via a unique H-atom transfer mechanism between the two involved thymine residues. Successful incorporation of SP into an oligonucleotide has been achieved via organic synthesis, which enables structural studies that reveal minor conformational changes in the SP-containing DNA. Here, we review the progress on SP photochemistry and photobiology in the past 50 years, which indicates a very rich SP photobiology that may exist beyond endospores.
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Affiliation(s)
- Peter Setlow
- Department of Molecular Biology and Biophysics, UConn Health, Farmington, Connecticut, USA
| | - Lei Li
- Department of Chemistry and Chemical Biology, Indiana University-Purdue University Indianapolis (IUPUI), Indianapolis, Indiana, 46202
- Department of Biochemistry and Molecular Biology & Department of Dermatology, Indiana University School of Medicine, Indianapolis, Indiana 46202
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4
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Friedline AW, Zachariah MM, Middaugh AN, Garimella R, Vaishampayan PA, Rice CV. Sterilization Resistance of Bacterial Spores Explained with Water Chemistry. J Phys Chem B 2015; 119:14033-44. [DOI: 10.1021/acs.jpcb.5b07437] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Anthony W. Friedline
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Malcolm M. Zachariah
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Amy N. Middaugh
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Ravindranath Garimella
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
| | - Parag A. Vaishampayan
- Biotechnology and Planetary Protection Group, Jet Propulsion Laboratory, California Institute of Technology, M/S 89-108, 4800 Oak Grove Drive, Pasadena, California 91109, United States
| | - Charles V. Rice
- Department of Chemistry and Biochemistry, Stephenson
Life Sciences Research Center, University of Oklahoma, 101 Stephenson
Parkway, Norman, Oklahoma 73019, United States
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5
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Friedline AW, Zachariah MM, Johnson K, Thomas KJ, Middaugh AN, Garimella R, Powell DR, Vaishampayan PA, Rice CV. Water behavior in bacterial spores by deuterium NMR spectroscopy. J Phys Chem B 2014; 118:8945-55. [PMID: 24950158 PMCID: PMC4216197 DOI: 10.1021/jp5025119] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
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Dormant bacterial spores are able
to survive long periods of time
without nutrients, withstand harsh environmental conditions, and germinate
into metabolically active bacteria when conditions are favorable.
Numerous factors influence this hardiness, including the spore structure
and the presence of compounds to protect DNA from damage. It is known
that the water content of the spore core plays a role in resistance
to degradation, but the exact state of water inside the core is a
subject of discussion. Two main theories present themselves: either
the water in the spore core is mostly immobile and the core and its
components are in a glassy state, or the core is a gel with mobile
water around components which themselves have limited mobility. Using
deuterium solid-state NMR experiments, we examine the nature of the
water in the spore core. Our data show the presence of unbound water,
bound water, and deuterated biomolecules that also contain labile
deuterons. Deuterium–hydrogen exchange experiments show that
most of these deuterons are inaccessible by external water. We believe
that these unreachable deuterons are in a chemical bonding state that
prevents exchange. Variable-temperature NMR results suggest that the
spore core is more rigid than would be expected for a gel-like state.
However, our rigid core interpretation may only apply to dried spores
whereas a gel core may exist in aqueous suspension. Nonetheless, the
gel core, if present, is inaccessible to external water.
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Affiliation(s)
- Anthony W Friedline
- Department of Chemistry and Biochemistry, Stephenson Life Sciences Research Center, University of Oklahoma , 101 Stephenson Parkway, Norman, Oklahoma 73019, United States
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Kaieda S, Setlow B, Setlow P, Halle B. Mobility of core water in Bacillus subtilis spores by 2H NMR. Biophys J 2014; 105:2016-23. [PMID: 24209846 DOI: 10.1016/j.bpj.2013.09.022] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 09/17/2013] [Accepted: 09/19/2013] [Indexed: 11/19/2022] Open
Abstract
Bacterial spores in a metabolically dormant state can survive long periods without nutrients under extreme environmental conditions. The molecular basis of spore dormancy is not well understood, but the distribution and physical state of water within the spore is thought to play an important role. Two scenarios have been proposed for the spore's core region, containing the DNA and most enzymes. In the gel scenario, the core is a structured macromolecular framework permeated by mobile water. In the glass scenario, the entire core, including the water, is an amorphous solid and the quenched molecular diffusion accounts for the spore's dormancy and thermal stability. Here, we use (2)H magnetic relaxation dispersion to selectively monitor water mobility in the core of Bacillus subtilis spores in the presence and absence of core Mn(2+) ions. We also report and analyze the solid-state (2)H NMR spectrum from these spores. Our NMR data clearly support the gel scenario with highly mobile core water (~25 ps average rotational correlation time). Furthermore, we find that the large depot of manganese in the core is nearly anhydrous, with merely 1.7% on average of the maximum sixfold water coordination.
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Affiliation(s)
- Shuji Kaieda
- Department of Biophysical Chemistry, Lund University, Lund, Sweden
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7
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Tiburski JH, Rosenthal A, Guyot S, Perrier-Cornet JM, Gervais P. Water Distribution in Bacterial Spores: A Key Factor in Heat Resistance. FOOD BIOPHYS 2013. [DOI: 10.1007/s11483-013-9312-5] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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8
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Kong L, Setlow P, Li YQ. Direct analysis of water content and movement in single dormant bacterial spores using confocal Raman microspectroscopy and Raman imaging. Anal Chem 2013; 85:7094-101. [PMID: 23815288 DOI: 10.1021/ac400516p] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heavy water (D2O) has a distinct molecular vibration spectrum, and this has been used to analyze the water content, distribution, and movement in single dormant Bacillus cereus spores using confocal Raman microspectroscopy and Raman imaging. These methods have been used to measure the kinetics of D2O release from spores suspended in H2O, the spatial distribution of D2O in spores, and the kinetics of D2O release from spores during dehydration in air at room temperature. The results obtained were as follows. (1) The Raman spectrum of single D2O-loaded dormant spores suggests that D2O in spores is in a relatively weak hydrogen-bonded mode, compared to the strong hydrogen-bonded mode in pure D2O. (2) The D2O content of individual spores in a population was somewhat heterogeneous. (3) The spatial distribution of D2O in single dormant spores is uneven, and is less dense in the central core region. Raman images of different molecular components indicate that the water distribution is somewhat different from those of proteins and Ca-dipicolinic acid. (4) Exchange of spore D2O with external H2O took place in less than 1 s. (5) However, release of spore D2O during air dehydration at room temperature was slow and heterogeneous and took 2-3 h for complete D2O release.
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Affiliation(s)
- Lingbo Kong
- Department of Physics, East Carolina University, Greenville, North Carolina 27858-4353, United States
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9
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He X, Li R, Huang G, Hwang HM, Jiang X. Influence of marine oligosaccharides on the response of various biological systems to UV irradiation. J Funct Foods 2013. [DOI: 10.1016/j.jff.2013.01.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
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10
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Segev E, Smith Y, Ben-Yehuda S. RNA dynamics in aging bacterial spores. Cell 2011; 148:139-49. [PMID: 22209493 DOI: 10.1016/j.cell.2011.11.059] [Citation(s) in RCA: 73] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 09/13/2011] [Accepted: 11/30/2011] [Indexed: 12/21/2022]
Abstract
Upon starvation, the bacterium Bacillus subtilis enters the process of sporulation, lasting several hours and culminating in formation of a spore, the most resilient cell type known. We show that a few days following sporulation, the RNA profile of spores is highly dynamic. In aging spores incubated at high temperatures, RNA content is globally decreased by degradation over several days. This degradation might be a strategy utilized by the spore to facilitate its dormancy. However, spores kept at low temperature exhibit a different RNA profile with evidence supporting transcription. Further, we demonstrate that germination is affected by spore age, incubation temperature, and RNA state, implying that spores can acquire dissimilar characteristics at a time they are considered dormant. We propose that, in contrast to current thinking, entering dormancy lasts a few days, during which spores are affected by the environment and undergo corresponding molecular changes influencing their emergence from quiescence.
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Affiliation(s)
- Einat Segev
- Department of Microbiology and Molecular Genetics, Institute for Medical Research Israel-Canada (IMRIC), The Hebrew University-Hadassah Medical School, The Hebrew University of Jerusalem, 91120 Jerusalem, Israel
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11
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New Insight into the Thermal Properties and the Biological Behaviour of the Bacterial Spores. FOOD BIOPHYS 2010. [DOI: 10.1007/s11483-010-9165-0] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
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12
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Spatially resolved characterization of water and ion incorporation in Bacillus spores. Appl Environ Microbiol 2010; 76:3275-82. [PMID: 20348293 DOI: 10.1128/aem.02485-09] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
We present the first direct visualization and quantification of water and ion uptake into the core of individual dormant Bacillus thuringiensis subsp. israelensis (B. thuringiensis subsp. israelensis) endospores. Isotopic and elemental gradients in the B. thuringiensis subsp. israelensis spores show the permeation and incorporation of deuterium in deuterated water (D(2)O) and solvated ions throughout individual spores, including the spore core. Under hydrated conditions, incorporation into a spore occurs on a time scale of minutes, with subsequent uptake of the permeating species continuing over a period of days. The distribution of available adsorption sites is shown to vary with the permeating species. Adsorption sites for Li(+), Cs(+), and Cl(-) are more abundant within the spore outer structures (exosporium, coat, and cortex) relative to the core, while F(-) adsorption sites are more abundant in the core. The results presented here demonstrate that elemental abundance and distribution in dormant spores are influenced by the ambient environment. As such, this study highlights the importance of understanding how microbial elemental and isotopic signatures can be altered postproduction, including during sample preparation for analysis, and therefore, this study is immediately relevant to the use of elemental and isotopic markers in environmental microbiology and microbial forensics.
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13
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Carstensen EL, Cox HA, Mercer WB, Natale LA. Passive Electrical Properties of Microorganisms: I. Conductivity of Escherichia coli and Micrococcus lysodeikticus. Biophys J 2009; 5:289-300. [PMID: 19431334 DOI: 10.1016/s0006-3495(65)86717-0] [Citation(s) in RCA: 49] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
Abstract
Effective conductivities are reported for the bacteria Escherichia coli and Micrococcus lysodeikticus over a range of environmental conductivity. The apparent conductivities of the organisms can be explained in terms of the properties of the cell wall. At low conductivities of the environment, the conductivity of the cell appears to be dominated by the counterions of the fixed charge of the cell wall. At higher conductivities of the suspending medium, evidence suggests that ions from the environment invade the cell wall causing an increase in the effective conductivity of the cell so that it takes on values roughly proportional to that of the environment. The model points to the usefulness of dielectric techniques in studies of the properties of intact cell walls.
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14
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Effect of the osmotic conditions during sporulation on the subsequent resistance of bacterial spores. Appl Microbiol Biotechnol 2008; 80:107-14. [DOI: 10.1007/s00253-008-1519-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2008] [Revised: 03/14/2008] [Accepted: 04/21/2008] [Indexed: 10/22/2022]
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15
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Carrera M, Zandomeni R, Sagripanti JL. Wet and dry density ofBacillus anthracisand otherBacillusspecies. J Appl Microbiol 2008; 105:68-77. [DOI: 10.1111/j.1365-2672.2008.03758.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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16
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ANAGNOSTOPOULOS GD, SIDHU HS. The Effect of Water Activity and theawControlling Solute on Spore Germination ofBacillus stearothermophilus. ACTA ACUST UNITED AC 2008. [DOI: 10.1111/j.1365-2672.1981.tb00898.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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17
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Kazakov S, Bonvouloir E, Gazaryan I. Physicochemical Characterization of Natural Ionic Microreservoirs: Bacillus subtilisDormant Spores. J Phys Chem B 2008; 112:2233-44. [DOI: 10.1021/jp077188u] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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18
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GUPPY MICHAEL, WITHERS PHILIP. Metabolic depression in animals: physiological perspectives and biochemical generalizations. Biol Rev Camb Philos Soc 2007. [DOI: 10.1111/j.1469-185x.1999.tb00180.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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FURUKAWA S, HAYAKAWA I. Mechanical Analysis of the Injury of Spores by Reciprocal Pressurization. FOOD SCIENCE AND TECHNOLOGY RESEARCH 2004. [DOI: 10.3136/fstr.10.13] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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20
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Westphal AJ, Price PB, Leighton TJ, Wheeler KE. Kinetics of size changes of individual Bacillus thuringiensis spores in response to changes in relative humidity. Proc Natl Acad Sci U S A 2003; 100:3461-6. [PMID: 12584363 PMCID: PMC152315 DOI: 10.1073/pnas.232710999] [Citation(s) in RCA: 133] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Using an automated scanning microscope, we report the surprising result that individual dormant spores of Bacillus thuringiensis grow and shrink in response to increasing and decreasing relative humidity. We simultaneously monitored the size of inorganic calibration particles. We found that the spores consistently swell in response to increased relative humidity, and shrink to near their original size on reexposure to dry air. Although the dispersion of swelling amplitudes within an ensemble of spores is wide (approximately 30% of the average amplitude), amplitudes for individual spores are highly correlated between different swelling episodes, suggesting that individual spores respond consistently to changes in humidity. We find evidence for two distinct time scales for swelling: one with a time scale of no more than approximately 50 s, and another with a time scale of approximately 8 min. We speculate that these two mechanisms may be due to rapid diffusion of water into the spore coat + cortex, followed by slower diffusion of water into the spore core, respectively. Humidity-dependent swelling may account for the greater kill effectiveness of spores by gas-phase chlorine dioxide, formaldehyde, and ethylene oxide at very high relative humidity.
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Affiliation(s)
- Andrew J Westphal
- Space Sciences Laboratory and Department of Physics, University of California, Berkeley, CA 94720, USA.
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21
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Leuschner RGK, Lillford PJ. Effects of hydration on molecular mobility in phase-bright Bacillus subtilis spores. MICROBIOLOGY (READING, ENGLAND) 2000; 146 ( Pt 1):49-55. [PMID: 10658651 DOI: 10.1099/00221287-146-1-49] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The molecular mobility of 31P and 13C in dormant Bacillus subtilis spore samples with different water concentrations was investigated by high-resolution solid-state NMR. Lowest molecular mobility was observed in freeze-dried preparations. Rehydration to a 10% weight increase resulted in increases in molecular motions and addition of excess water furthered this effect. A spore slurry which had been freeze-dried displayed after addition of excess water similar NMR spectra to native wet preparations. Dipicolinic acid (DPA), which is mainly located in the core, was detected at all hydration levels in 13C cross-polarization magic angle spinning (CPMAS) but not in single-pulse magic angle spinning (SPMAS) spectra, indicating that hydration had no effect on its mobility. The molecular mobility of 31P, present mainly in core-specific components, was strongly dependent on hydration. This result suggests reversible water migration between inner spore compartments and the environment, whereas 13C spectra of DPA indicate that it is immobilized in a water-insoluble network in the core. Scanning transmission electron microscopy revealed that freeze-dried spores were significantly longer and narrower than fully hydrated spores and had a 3% smaller volume.
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22
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WARTH AD, OHYE DF, MURRELL WG. Location and composition of spore mucopeptide in Bacillus species. ACTA ACUST UNITED AC 1998; 16:593-609. [PMID: 13999017 PMCID: PMC2106237 DOI: 10.1083/jcb.16.3.593] [Citation(s) in RCA: 71] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Spore integuments of Bacillus coagulans were prepared containing nearly all the hexosamine and α, ε-diaminopimelic acid (DAP) present in intact spores. Subsequent autolytic action resulted in the destruction and removal of the residual cortical structure and "cortical membrane" leaving the appearance of the inner and outer spore coats unchanged in electron micrographs. Concurrently, all the hexosamine and DAP in the preparation was released mainly as non-diffusible mucopeptide containing alanine, glutamic acid, DAP, and all the glucosamine and muramic acid. Some diffusible peptides containing alanine, glutamic acid, and DAP were also present but there was little protein or carbohydrate. Lysozyme digestion of integument preparations from heated spores of Bacillus 636, B. subtilis, B. coagulans, and B. stearothermophilus specifically removed the residual cortex and cortical membrane with the release of the mucopeptide. In B. cereus T, only the residual cortex and part of the mucopeptide were solubilized by lysozyme. The effect of several reagents and enzymes upon the appearance and removal of hexosamine from B. coagul ans spore integuments is reported. The results show that spore mucopeptide is mainly located in the residual cortex and cortical membrane and suggest that these structures consist essentially of mucopeptide. The implications of these results in relation to the "contractile cortex" theory of heat resistance in spores are discussed.
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GERHARDT P, JUDGE JA. POROSITY OF ISOLATED CELL WALLS OF SACCHAROMYCES CEREVISIAE AND BACILLUS MEGATERIUM. J Bacteriol 1996; 87:945-51. [PMID: 14137635 PMCID: PMC277115 DOI: 10.1128/jb.87.4.945-951.1964] [Citation(s) in RCA: 75] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Gerhardt, Philipp (The University of Michigan, Ann Arbor), and Jean A. Judge. Porosity of isolated cell walls of a yeast and a bacillus. J. Bacteriol. 87:945-951. 1964.-Decagram masses of cell walls were isolated from Saccharomyces cerevisiae and Bacillus megaterium; their porosity was examined by measuring the extent of uptake with polyethylene glycols and dextrans varying in molecular weight from 62 to 2,000,000. The results indicated that both walls are heteroporous. The near equality of extrapolated water-uptake values and determined moisture contents suggested that water in the cell walls is mainly free for distribution of solutes. Polymers with molecular weights of 4,500 and above were excluded by the yeast walls, and those with molecular weights of 57,000 were excluded by the bacillus walls; from these results, maximal openings of 36 and 107 A, respectively, were calculated. Electron micrographs of shadowed, stained, and sectioned walls revealed fine structure not inconsistent with heteroporosity, but the predicted openings were not seen. Altogether, in structure and permeability behavior, the cell walls were like a random meshwork of cross-linked macromolecular strands.
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Abstract
Endospores of a bacterium Bacillus subtilis and ascospores of a yeast Saccharomyces cerevisiae contained almost all the activities for the same enzymes as vegetative cells. The biotechnological potential of spores was studied by selecting adenosine 5'-triphosphatase and alkaline phosphatase in bacterial and yeast spores, respectively, as model enzymes. The activity of both enzymes was efficiently expressed when the spores were treated by physical (sonication or electric field pulse) and chemical (organic solvents or detergents) methods. The yeast spores were immobilized in polyacrylamide gel without any appreciable loss of activity. The immobilized spores were packed in a column and used successfully for the continuous reactions of alkaline phosphatase and glyoxalase I. The microbial spores were confirmed to be promising as a biocatalyst for the production of useful chemicals in bioreactor systems.
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Affiliation(s)
- K Murata
- Research Institute for Food Science, Kyoto University, Japan
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25
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Beaman TC, Gerhardt P. Heat resistance of bacterial spores correlated with protoplast dehydration, mineralization, and thermal adaptation. Appl Environ Microbiol 1986; 52:1242-6. [PMID: 3098170 PMCID: PMC239215 DOI: 10.1128/aem.52.6.1242-1246.1986] [Citation(s) in RCA: 110] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
Twenty-eight types of lysozyme-sensitive spores among seven Bacillus species representative of thermophiles, mesophiles, and psychrophiles were obtained spanning a 3,000-fold range in moist-heat resistance. The resistance within species was altered by demineralization of the native spores to protonated spores and remineralization of the protonated spores to calcified spores and by thermal adaptation at maximum, optimum, and minimum sporulation temperatures. Protoplast wet densities, and thereby protoplast water contents, were obtained by buoyant density sedimentation in Nycodenz gradients (Nyegaard and Co., Oslo, Norway). Increases in mineralization and thermal adaptation caused reductions in protoplast water content between limits of ca. 57 and 28% (wet weight basis), and thereby correlated with increases in sporal heat resistance. Above and below these limits, however, increases in mineralization and thermal adaptation correlated with increases in sporal resistance independently of unchanged protoplast water contents. All three factors evidently contributed to and were necessary for heat resistance of the spores, but dehydration predominated.
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Nakashio S, Gerhardt P. Protoplast dehydration correlated with heat resistance of bacterial spores. J Bacteriol 1985; 162:571-8. [PMID: 3988704 PMCID: PMC218886 DOI: 10.1128/jb.162.2.571-578.1985] [Citation(s) in RCA: 48] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Water content of the protoplast in situ within the fully hydrated dormant bacterial spore was quantified by use of a spore in which the complex of coat and outer (pericortex) membrane was genetically defective or chemically removed, as evidenced by susceptibility of the cortex to lysozyme and by permeability of the periprotoplast integument to glucose. Water content was determined by equilibrium permeability measurement with 3H-labeled water (confirmed by gravimetric measurement) for the entire spore, with 14C-labeled glucose for the integument outside the inner (pericytoplasm) membrane, and by the difference for the protoplast. The method was applied to lysozyme-sensitive spores of Bacillus stearothermophilus, B. subtilis, B. cereus, B. thuringiensis, and B. megaterium (four types). Comparable lysozyme-resistant spores, in which the outer membrane functioned as the primary permeability barrier to glucose, were employed as controls. Heat resistances were expressed as D100 values. Protoplast water content of the lysozyme-sensitive spore types correlated with heat resistance exponentially in two distinct clusters, with the four B. megaterium types in one alignment, and with the four other species types in another. Protoplast water contents of the B. megaterium spore types were sufficiently low (26 to 29%, based on wet protoplast weight) to account almost entirely for their lesser heat resistance. Corresponding values of the other species types were similar or higher (30 to 55%), indicating that these spores depended on factors additional to protoplast dehydration for their much greater heat resistance.
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Beaman TC, Koshikawa T, Pankratz H, Gerhardt P. Dehydration partitioned within core protoplast accounts for heat resistance of bacterial spores. FEMS Microbiol Lett 1984. [DOI: 10.1111/j.1574-6968.1984.tb01242.x] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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Koshikawa T, Beaman TC, Pankratz HS, Nakashio S, Corner TR, Gerhardt P. Resistance, germination, and permeability correlates of Bacillus megaterium spores successively divested of integument layers. J Bacteriol 1984; 159:624-32. [PMID: 6430874 PMCID: PMC215689 DOI: 10.1128/jb.159.2.624-632.1984] [Citation(s) in RCA: 46] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
A variant strain that produced spores lacking exosporium was isolated from a culture of Bacillus megaterium QM-B1551. Two additional spore morphotypes were obtained from the parent and variant strains by chemical removal of the complex of coat and outer membrane. Among the four morphotype spores, heat resistance did not correlate with total water content, wet density, refractive index, or dipicolinate or cation content, but did correlate with the volume ratio of protoplast to protoplast plus cortex. The divestment of integument layers exterior to the cortex had little influence on heat resistance. Moreover, the divestment did not change the response of either the parent or the variant spores to various germination-initiating agents, except for making the spores susceptible to germination by lysozyme. The primary permeability barrier to glucose for the intact parent and variant spores was found to be the outer membrane, whereas the barrier for the divested spores was the inner membrane.
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Tisa LS, Koshikawa T, Gerhardt P. Wet and dry bacterial spore densities determined by buoyant sedimentation. Appl Environ Microbiol 1982; 43:1307-10. [PMID: 6285824 PMCID: PMC244232 DOI: 10.1128/aem.43.6.1307-1310.1982] [Citation(s) in RCA: 38] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The wet densities of various types of dormant bacterial spores and reference particles were determined by centrifugal buoyant sedimentation in density gradient solutions of three commercial media of high chemical density. With Metrizamide or Renografin, the wet density values for the spores and permeable Sephadex beads were higher than those obtained by a reference direct mass method, and some spore populations were separated into several density bands. With Percoll, all of the wet density values were about the same as those obtained by the direct mass method, and only single density bands resulted. The differences were due to the partial permeation of Metrizamide and Renografin, but not Percoll, into the spores and the permeable Sephadex beads. Consequently, the wet density of the entire spore was accurately represented only by the values obtained with the Percoll gradient and the direct mass method. The dry densities of the spores and particles were determined by gravity buoyant sedimentation in a gradient of two organic solvents, one of high and the other of low chemical density. All of the dry density values obtained by this method were about the same as those obtained by the direct mass method.
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Beaman TC, Greenamyre JT, Corner TR, Pankratz HS, Gerhardt P. Bacterial spore heat resistance correlated with water content, wet density, and protoplast/sporoplast volume ratio. J Bacteriol 1982; 150:870-7. [PMID: 6802802 PMCID: PMC216440 DOI: 10.1128/jb.150.2.870-877.1982] [Citation(s) in RCA: 69] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Five types of dormant Bacillus spores, between and within species, were selected representing a 600-fold range in moist-heat resistance determined as a D100 value. The wet and dry density and the solids and water content of the entire spore and isolated integument of each type were determined directly from gram masses of material, with correction for interstitial water. The ratio between the volume occupied by the protoplast (the structures bounded by the inner pericytoplasm membrane) and the volume occupied by the sporoplast (the structures bounded by the outer pericortex membrane) was calculated from measurements made on electron micrographs of medially thin-sectioned spores. Among the various spore types, an exponential increase in the heat resistance correlated directly with the wet density and inversely with the water content and with the protoplast/sporoplast volume ratio. Altogether with results supported a hypothesis that the extent of heat resistance is based in whole or in part on the extent of dehydration and diminution of the protoplast in the dormant spore, without implications about physiological mechanisms for attaining this state.
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Reich RR, Morien LL. Influence of environmental storage relative humidity on biological indicator resistance, viability, and moisture content. Appl Environ Microbiol 1982; 43:609-14. [PMID: 7073275 PMCID: PMC241882 DOI: 10.1128/aem.43.3.609-614.1982] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023] Open
Abstract
The effect of environmental storage relative humidity (RH) on the moisture content, viability, and moist heat and gaseous ethylene oxide (EO) resistance of biological indicators (BIs) was evaluated. No statistically significant difference was observed between the initial Bacillus stearothermophilus spore population and the spore population of BIs stored at 20 degrees C and 0, 20, 44, of 55% RH or under ambient, 4 degrees C, or -20 degrees C conditions after 12 months. A statistically significant decrease in moist heat resistance from initial starting levels was found for BIs stored at 20 degrees C and either 0 or 20% RH. There was a statistically significant decrease in the B. subtilis BI spore population, compared with initial levels, when the BIs were stored at 20 degrees C and 0% RH concomitant with a significant increase in their EO resistance. BI storage at 20 degrees C and 20 or 44% RH, or under ambient, 4 degrees C, or -20 degrees C conditions, had no significant effect on EO resistance. BIs stored at 20 degrees C and 66% RH demonstrated a significantly lower EO resistance compared with starting levels.
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Zajic JE, Inculet II, Martin P. Basic concepts in microbial aerosols. ADVANCES IN BIOCHEMICAL ENGINEERING/BIOTECHNOLOGY 1982. [DOI: 10.1007/3540114645_2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Hanlin JH, Cloutier MJ, Slepecky RA. Heat sensitization of bacterial spores after exposure to ethidium bromide, acriflavine, or daunomycin. Appl Environ Microbiol 1981; 42:79-82. [PMID: 6789768 PMCID: PMC243966 DOI: 10.1128/aem.42.1.79-82.1981] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
A 20-min exposure of 10(7) unmodified spores of either Bacillus subtilis NCTC 3610 (harvested from potato-dextrose agar plus manganese) or Bacillus megaterium ATCC 19213 (harvested from nutrient agar plus manganese) per ml to 5 microgram of ethidium bromide per ml did not kill the spores (recovered on TAM [thermoacidurans agar modified]-plus thymidine medium). However, in both cases, the ability to survive various heat treatments was reduced after exposure of the spores to ethidium bromide. With B. subtilis, a 10-min heat treatment at 85 degrees C of unexposed spores resulted in an 85% survival rate, whereas only 50% of the ethidium bromide-exposed spores survived. With B. megaterium similar results were obtained at 75 degrees C; 77% of the unexposed spores survived, whereas only 31% of the ethidium bromide-exposed spores survived. Similarly, a 10-min exposure of B. subtilis spores to 0.005 microgram of acriflavine per ml did not kill unheated spores; however, the ability of the spores to survive exposure at 85 degrees C for 10 min was reduced to 40%. After exposure to 10 microgram of daunomycin per ml, the survival rate was 35%. Binding studies with ethidium bromide showed strong binding to spores, but as yet, the site of binding is unknown.
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Algie JE. The heat resistance of bacterial spores due to their partial dehydration by reverse osmosis. Curr Microbiol 1980. [DOI: 10.1007/bf02601807] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Setlow B, Setlow P. Measurements of the pH within dormant and germinated bacterial spores. Proc Natl Acad Sci U S A 1980; 77:2474-6. [PMID: 6771755 PMCID: PMC349422 DOI: 10.1073/pnas.77.5.2474] [Citation(s) in RCA: 80] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
The pH within the core or central region of dormant spores of Bacillus cereus and B. megaterium is 6.3-6.4 irrespective of the external pH. However, the spore's internal pH rises to 7.3-7.5 upon germination. The low internal pH of the dormant spore may be a contributing factor to its metabolic dormancy.
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Waites W, Stansfield R, Bayliss CE. The effect of sporulation medium on the structure and heat resistance of spores ofClosridium bifermentans. FEMS Microbiol Lett 1979. [DOI: 10.1111/j.1574-6968.1979.tb03340.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
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Braune W, Sanke H. [Interferometric studies of the dynamics of hydration and dry matter content during light-dependent germination of the Anabaena variabilis Kützing akinetes]. ZEITSCHRIFT FUR ALLGEMEINE MIKROBIOLOGIE 1979; 19:535-46. [PMID: 120999 DOI: 10.1002/jobm.3630190803] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Calculations following interference-microscopical measurements performed on akinetes (A), heterocyts (H), and "vegetative" cells (F) of the Cyanobacterium (blue-green alga) Anabaena variabilis resulted in significant higher values of mean absolute dry matter content of the akinetes (2.06 . 10(-10) g; as compared to 0.46 . 10(-10) g and 0.31 . 10(-10) g for H and F, respectively). tthe water content of these resting cells (63%) was significantly lower than in the other two types of cells (H: 85%, F: 77%). Light exposition of the akinetes in fresh nutrition medium (i. e., conditions allowing germination within 30--50 h) resulted in a decrease of the relative dry matter content so that already in the period preceding the outgrowth of the germling the water content of the vegetative cells was achieved. Simultaneously their volume increased by the uptake of water; whereas the absolute content of dry matter remained constant or was even temporarily diminished during the first period. Only in the second period the values increased in some cases and then remained constant up to germination. The increased dry matter content, however, was not a precondition necessary for the germination of the akinetes. In darkness under otherwise unaltered conditions the values remained unchanged or, after a light period, came back to the initial level. The results demonstrate that formation and germination of the resting cells of Cyanobacteria as well are connected with an alteration in the hydratation level, i. e., in cells which continuously are kept under water saturated conditions. This increase by hydratation during the germination period is, as the germination process itself, strictly controlled by light.
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Crow VL, Pritchard GG. Fructose 1,6-diphosphate-activated L-lactate dehydrogenase from Streptococcus lactis: kinetic properties and factors affecting activation. J Bacteriol 1977; 131:82-91. [PMID: 17595 PMCID: PMC235394 DOI: 10.1128/jb.131.1.82-91.1977] [Citation(s) in RCA: 85] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
The L-(+)-lactate dehydrogenase (L-lactate:NAD+ oxidoreductase, EC 1.1.1.27) of Streptococcus lactis C10, like that of other streptococci, was activated by fructose 1,6-diphosphate (FDP). The enzyme showed some activity in the absence of FDP, with a pH optimum of 8.2; FDP decreased the Km for both pyruvate and reduced nicotinamide adenine dinucleotide (NADH) and shifted the pH optimum to 6.9. Enzyme activity showed a hyperbolic response to both NADH and pyruvate in all the buffers tried except phosphate buffer, in which the response to increasing NADH was sigmoidal. The FDP concentration required for half-maximal velocity (FDP0.5V) was markedly influenced by the nature of the assay buffer used. Thus the FDP0.5V was 0.002 mM in 90 mM triethanolamine buffer, 0.2 mM in 90 mM tris(hydroxymethyl)aminomethanemaleate buffer, and 4.4 mM in 90 mM phosphate buffer. Phosphate inhibition of FDP binding is not a general property of streptococcal lactate dehydrogenase, since the FDP0.5V value for S. faecalis 8043 lactate dehydrogenase was not increased by phosphate. The S. faecalis and S. lactis lactate dehydrogenases also differed in that Mn2+ enhanced FDP binding in S. faecalis but had no effect on the S. lactis dehydrogenase. The FDP concentration (12 to 15 mM) found in S. lactis cells during logarithmic growth on a high-carbohydrate (3% lactose) medium would be adequate to give almost complete activation of the lactate dehydrogenase even if the high FDP0.5V value found in 90 mM phosphate were similar to the FDP requirement in vivo.
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Gould GW. Recent advances in the understanding of resistance and dormancy in bacterial spores. THE JOURNAL OF APPLIED BACTERIOLOGY 1977; 42:297-309. [PMID: 18433 DOI: 10.1111/j.1365-2672.1977.tb00697.x] [Citation(s) in RCA: 63] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Thompson J. Characteristics and energy requirements of an alpha-aminoisobutyric acid transport system in Streptococcus lactis. J Bacteriol 1976; 127:719-30. [PMID: 8422 PMCID: PMC232977 DOI: 10.1128/jb.127.2.719-730.1976] [Citation(s) in RCA: 57] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Galactose-grown cells of Streptococcus lactis ML3 acculated alpha-aminoisobutyric acid (AIB) by using energy derived from glycolysis and arginine catabolism. The transport system displayed low-affinity Michaelis-Menten saturation kinetics. Using galactose or arginine as energy sources, similar V max and K m values for AIB entry were obtained, but on prolonged incubation the intracellular steady-state concentration of AIB in cells metabolizing arginine was only 65 to 70% that attained by glycolyzing cells. Efflux of AIB FROM PRELOADED CElls was temperature dependent and exhibited the characteristics of a first-order reaction. The rate of AIB exit was accelerated two- to threefold in the presence of metabolizable energy sources. Metabolic inhibitors including p-chloromercuribenzoate, dinitrophenol, azide, arsentate, and N, N'-dicyclohexylcarbodiimide either prevented or greatly reduced AIB uptake. Fluoride, iodoacetate and N-ethylmaleimide abolished galactose-dependent, but not arginine-energized, AIB uptake. K+ and Rb+ reduced the steady-state intracellular AIB concentration by approximately 40%, and these cations also induced rapid efflux of solute from actively transporting cells. Equivalent concentrations (10 mM) of Na+, Li+, or NH4+ were much less inhibitory. The proton-conducting ionophores tetrachlorosalicylanilide and carbonylcyanide m-chlorophenlyhydrazone abolished uptake and induced AIB efflux even though glycolysis and arginine catabolism continued at 60 and 140%, respectively, of control rates. A proton motive force is most likely involved in the active transport of AIB, whereas data from efflux studies suggest that energy is coupled to AIB exit in cells of S. lactis ML3.
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Jyssum K. Osmotically induced changes of cell spaces in Neisseria meningitidis competence variants. ACTA PATHOLOGICA ET MICROBIOLOGICA SCANDINAVICA. SECTION B, MICROBIOLOGY 1976; 84:38-44. [PMID: 814783 DOI: 10.1111/j.1699-0463.1976.tb01898.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The volume of the whole cell and the fraction of the intact cell bounded by the cytoplasmic membrane (protoplast volume) have been measured by dextran and 14C-sucrose exclusion spaces in Neisseria meningitidis competence variants. Increase in external osmotic pressure causes contraction of the protoplast volume. Increasing osmolality due to NaCl and MgCl2 also causes contraction of the volume of the whole cell, whereas increasing concentrations of sucrose cause little or no change in the whole cell volume. The experiments demonstrate a significant difference between competent (cp+) and incompetent (cp-) cells. The cp+ protoplast have a far higher capacity for swelling during decreasing osmolality, and for shrinkage during increasing osmolality. Comparison of spheroplasts obtained by autolysis as well as by the penicillin technique indicates that the average cp+ spheroplast is larger than the average cp- one. The significance of the difference in structure of cp+ and cp- protoplasts has been discussed.
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Gould GW, Dring GJ. Heat resistance of bacterial endospores and concept of an expanded osmoregulatory cortex. Nature 1975; 258:402-5. [PMID: 1196370 DOI: 10.1038/258402a0] [Citation(s) in RCA: 104] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
The extreme resistance of bacterial endospores to heat may result from dehydration of the central protoplast brought about and maintained by osmotic activity of expanded electronegative peptidoglycan polymer, and positively charged counterions associated with it, in the surrounding cortex. The cortex may thus act as a specialised osmoregulatory organelle. Changes in the environment which would be expected reversibly to affect osmotic properties alter the heat resistance of spores.
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Setlow P. Identification and localization of the major proteins degraded during germination of Bacillus megaterium spores. J Biol Chem 1975. [DOI: 10.1016/s0021-9258(19)40829-6] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Abstract
The kinetic properties of pyruvate kinase (ATP:pyruvate-phosphotransferase, EC 2.7.1.40) from Streptococcus lactis have been investigated. Positive homotropic kinetics were observed with phosphoenolpyruvate and adenosine 5'-diphosphate, resulting in a sigmoid relationship between reaction velocity and substrate concentrations. This relationship was abolished with an excess of the heterotropic effector fructose-1,6-diphosphate, giving a typical Michaelis-Menten relationship. Increasing the concentration of fructose-1,6-diphosphate increased the apparent V(max) values and decreased the K(m) values for both substrates. Catalysis by pyruvate kinase proceeded optimally at pH 6.9 to 7.5 and was markedly inhibited by inorganic phosphate and sulfate ions. Under certain conditions adenosine 5'-triphosphate also caused inhibition. The K(m) values for phosphoenolpyruvate and adenosine 5'-diphosphate in the presence of 2 mM fructose-1,6-diphosphate were 0.17 mM and 1 mM, respectively. The concentration of fructose-1,6-diphosphate giving one-half maximal velocity with 2 mM phosphoenolpyruvate and 5 mM adenosine 5'-diphosphate was 0.07 mM. The intracellular concentrations of these metabolites (0.8 mM phosphoenolpyruvate, 2.4 mM adenosine 5'-diphosphate, and 18 mM fructose-1,6-diphosphate) suggest that the pyruvate kinase in S. lactis approaches maximal activity in exponentially growing cells. The role of pyruvate kinase in the regulation of the glycolytic pathway in lactic streptococci is discussed.
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Setlow P. Inability of detect cyclic AMP in vegetative or sporulating cells or dormant spores of Bacillus megaterium. Biochem Biophys Res Commun 1973; 52:365-72. [PMID: 4351135 DOI: 10.1016/0006-291x(73)90720-1] [Citation(s) in RCA: 64] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Hachisuka Y, Tochikubo K. Reactivative action of ethylenediaminetetraacetic acid or dipicolinic acid on inactive glucose dehydrogenase obtained from heated spores of Bacillus subtilis. J Bacteriol 1971; 107:442-7. [PMID: 4329730 PMCID: PMC246944 DOI: 10.1128/jb.107.2.442-447.1971] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Partially purified inactive glucose dehydrogenase obtained from spores which were heated at 87 or 90 C for 30 min is converted to an active from by the addition of ethylenediaminetetraacetic acid, dipicolinic acid, or some salts. The molecular weight of the inactive glucose dehydrogenase in the heated spores is about one-half of that of the active glucose dehydrogenase in the intact resting spores. The possibility is discussed that the active glucose dehydrogenase in the intact resting spores divides into subunits and is converted to stable and inactive form during heating of spores at a particular range of temperature (87 to 90 C).
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Affiliation(s)
- Giuseppe Falcone
- Department of Biological Sciences, University of Cincinnati, Cincinnati, Ohio, USA
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