Abstract:
:The cell envelope of gram-negative bacteria is responsible for many important biological functions: it plays a structural role, it accommodates the selective transfer of material across the cell wall, it undergoes changes made necessary by growth and division, and it transfers information about the environment into the cell. Thus, an accurate quantification of cell mechanical properties is required not only to understand physiological processes but also to help elucidate the relationship between cell surface structure and function. We have used a novel, atomic force microscopy (AFM)-based approach to probe the mechanical properties of single bacterial cells by applying a constant compressive force to the cell under fluid conditions while measuring the time-dependent displacement (creep) of the AFM tip due to the viscoelastic properties of the cell. For these experiments, we chose a representative gram-negative bacterium, Pseudomonas aeruginosa PAO1, and we used regular V-shaped AFM cantilevers with pyramid-shaped and colloidal tips. We find that the cell response is well described by a three-element mechanical model which describes an effective cell spring constant, k(1), and an effective time constant, tau, for the creep deformation. Adding glutaraldehyde, an agent that increases the covalent bonding of the cell surface, produced a significant increase in k(1) together with a significant decrease in tau. This work represents a new attempt toward the understanding of the nanomechanical properties of single bacteria while they are under fluid conditions, which could be of practical value for elucidating, for instance, the biomechanical effects of drugs (such as antibiotics) on pathogens.
journal_name
J Bacterioljournal_title
Journal of bacteriologyauthors
Vadillo-Rodriguez V,Beveridge TJ,Dutcher JRdoi
10.1128/JB.00132-08subject
Has Abstractpub_date
2008-06-01 00:00:00pages
4225-32issue
12eissn
0021-9193issn
1098-5530pii
JB.00132-08journal_volume
190pub_type
杂志文章abstract::The Bacillus spo0H gene codes for sigma H, which, as part of the RNA polymerase holoenzyme E sigma H, is responsible for the transcription of several genes which are expressed at the beginning of the sporulation process. In this communication, we examined the regulation of the spo0H gene of Bacillus subtilis by using ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.173.2.521-529.1991
更新日期:1991-01-01 00:00:00
abstract::Recipient (F(-)) cells of Escherichia coli are sensitive to an excess of Hfr donor cells. This phenomenon of lethal zygosis is associated with conjugation and is observed as a continuous fall in F(-) viable cells during liquid mating, or as inhibition of F(-) growth on solid media. One class of survivors, which arose ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.117.1.100-106.1974
更新日期:1974-01-01 00:00:00
abstract::Twenty-four Lactobacillus plantarum supermotifs (LPSMs) with lengths from approximately 800 to 1,000 nucleotides were identified in the L. plantarum genome. LPSMs were conserved in other L. plantarum strains but not in other species. Secondary structure analysis predicted that LPSMs may fold into cruciform-like struct...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.01672-08
更新日期:2009-05-01 00:00:00
abstract::We investigated an osmotic remedial mutant of Saccharomyces which was deficient in galactose-1-phosphate uridyl transferase. Both the rate of growth and the transferase activity of the mutant culture were dependent on the osmotic activity of the growth medium. Organic and ionic solutes proved to be equally effective i...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.95.3.1103-1110.1968
更新日期:1968-03-01 00:00:00
abstract::We used a Southern hybridization assay to locate precisely the sites at which DNA replication is arrested in the terminus region of the Escherichia coli chromosome. The assay was based on the properties of restriction fragments that contain stalled replication forks. Replication forks that entered the terminus from th...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.170.9.4293-4298.1988
更新日期:1988-09-01 00:00:00
abstract::By extracellular labeling of peptides of intact Corynebacterium diphtheriae, followed by fractionation of the cells and chain completion by isolated polysomes, it is shown that diphtheria toxin is formed and secreted cotranslationally by membrane-bound polysomes; free polysomes from none. Moreover, when the chains on ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.141.1.184-189.1980
更新日期:1980-01-01 00:00:00
abstract::The morphology, on MacConkey's agar, of colonies of the bacteria commonly found in enteric specimens is sufficiently characteristic and distinctive, when observed with transmitted oblique illumination and a low-power stereoscopic microscope, to enable identification at the generic (and occasionally the species) level ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.93.6.1897-1905.1967
更新日期:1967-06-01 00:00:00
abstract::The mocC gene encoded by the octopine/mannityl opine-type Ti plasmid pTi15955 is related at the nucleotide sequence level to mas1' encoded by the T region of this plasmid. While Mas1 is required for the synthesis of mannopine (MOP) by crown gall tumor cells, MocC is essential for the utilization of MOP by Agrobacteriu...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.178.11.3285-3292.1996
更新日期:1996-06-01 00:00:00
abstract::High-resolution electron microscopy of polarly flagellated bacteria revealed that their flagella originate at a circular, differentiated portion of the cytoplasmic membrane approximately 25 nm in diameter. The flagella also have discs attaching them to the cell wall. These attachment discs are extremely resistant to l...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.100.1.512-521.1969
更新日期:1969-10-01 00:00:00
abstract:UNLABELLED:The σE envelope stress response is an essential signal transduction pathway which detects and removes mistargeted outer membrane (OM) β-barrel proteins (OMPs) in the periplasm of Escherichia coli It relies on σE, an alternative sigma factor encoded by the rpoE gene. Here we report a novel mutation, a nucleot...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00340-16
更新日期:2016-08-11 00:00:00
abstract::Cybulska, Janina (State Institute of Hygiene, Warsaw, Poland), and J. Jeljaszewicz. Bacteriostatic activity of serum against staphylococci. J. Bacteriol. 91:953-962. 1966.-Antistaphylococcal activity of normal serum against strains exhibiting various patterns of coagulase, clumping-factor, and staphylokinase productio...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.91.3.953-962.1966
更新日期:1966-03-01 00:00:00
abstract::The presence of acetate and pyruvate groups in Klebsiella capsular polysaccharides may be demonstrated and estimated quantitatively by running the proton magnetic resonance spectrum of the polysaccharide (as sodium salt) in deuterium oxide at 95 C. Such spectra also permit an assessment to be made of the number of alp...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.113.3.1345-1347.1973
更新日期:1973-03-01 00:00:00
abstract::In this report, we show that biofilm formation by Streptococcus pneumoniae serotype 19 gives rise to variants (the small mucoid variant [SMV] and the acapsular small-colony variant [SCV]) differing in capsule production, attachment, and biofilm formation compared to wild-type strains. All biofilm-derived variants harb...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00707-08
更新日期:2008-10-01 00:00:00
abstract::The major cold shock protein of Escherichia coli, CS7.4, is produced at a level of 13% of total protein synthesis upon a temperature shift from 37 to 10 degrees C. The transcription of its gene (cspA) was found to be tightly regulated and induced only at low temperature. In addition, the cspA mRNA was extremely unstab...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.174.12.3867-3873.1992
更新日期:1992-06-01 00:00:00
abstract::A three-dimensional tracking microscope was used to quantify the effects of temperature (50 to 80 degrees C) and pH (2 to 4) on the motility of Sulfolobus acidocaldarius, a thermoacidophilic archaeon. Swimming speed and run time increased with temperature but remained relatively unchanged with increasing pH. These res...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.181.13.4020-4025.1999
更新日期:1999-07-01 00:00:00
abstract::Mycoplasma pneumoniae cytadherence is mediated by a specialized, polar attachment organelle. Certain spontaneously arising cytadherence mutants (designated class I) lack HMW2, fail to localize the adhesin protein P1 to the attachment organelle, and exhibit accelerated turnover of proteins HMW1, HMW3, and P65. Insertio...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.181.14.4404-4410.1999
更新日期:1999-07-01 00:00:00
abstract::Germination and outgrowth of ascospores of Saccharomyces cerevisiae 4579 require both methionine and adenine, whereas leucine is only required for outgrowth. The methionine requirement may be satisfied by S-adenosylmethionine, but this sulfonium compound will not substitute for adenine. Between 30 and 70 min of protei...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.131.1.63-68.1977
更新日期:1977-07-01 00:00:00
abstract::N15 is the only bacteriophage of Escherichia coli known to lysogenize as a linear plasmid. Clear-plaque mutations lie in at least two regions of the 46-kb genome. We have cloned, sequenced, and characterized the primary immunity region, immB. This region contains a gene, cB, whose product shows homology to lambdoid ph...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.178.10.2902-2910.1996
更新日期:1996-05-01 00:00:00
abstract::Azotobacter vinelandii is a bacterium which undergoes a differentiation process leading to the formation of metabolically dormant cysts. During the encystment process, A. vinelandii produces alkylresorcinol lipids (ARs) that replace the membrane phospholipids and are also components of the layers covering the cyst. Th...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.01946-12
更新日期:2013-04-01 00:00:00
abstract::Broad-host-range plasmids and cloning vectors were conjugatively transferred to Acetobacter xylinum. One of the plasmids, RP4::Mu cts61, was used for the insertion of Tn1 into the 16-, 44-, and 64-kilobase-pair plasmids of A. xylinum. The Tn1-labeled plasmids could be mobilized by a helper plasmid. Many of the Tn1 ins...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.165.1.336-339.1986
更新日期:1986-01-01 00:00:00
abstract::5-methylcytosine in chromosomal DNA represents a potential source of frequent spontaneous mutation for hyperthermophiles. To determine the relevance of this threat for the archaeon Sulfolobus acidocaldarius, the mode of GGCC methylation by its restriction-modification system, SuaI, was investigated. Distinct isoschizo...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.185.15.4657-4661.2003
更新日期:2003-08-01 00:00:00
abstract::2-Carboxybenzaldehyde dehydrogenase from the phenanthrene-degrading bacterium Nocardioides sp. strain KP7 was purified and characterized. The purified enzyme had a molecular mass of 53 kDa by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and 205 kDa by gel filtration chromatography. Thus, the homotetramer ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.179.20.6488-6494.1997
更新日期:1997-10-01 00:00:00
abstract::Comamonas sp. strain CNB-1 degrades nitrobenzene and chloronitrobenzene via the intermediates 2-aminomuconate and 2-amino-5-chloromuconate, respectively. Deamination of these two compounds results in the release of ammonia, which is used as a source of nitrogen for bacterial growth. In this study, a novel deaminase wa...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.01762-06
更新日期:2007-04-01 00:00:00
abstract::The peptidoglycan layer surrounding the photosynthetic organelles (cyanelles) of the protist Cyanophora paradoxa is thought to be a relic of their cyanobacterial ancestors. The separation of muropeptides by gel filtration and reverse-phase high-performance liquid chromatography revealed four different muropeptide mono...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/jb.178.2.332-339.1996
更新日期:1996-01-01 00:00:00
abstract::The bacterial response to stress is controlled by two proteins, RelA and SpoT. RelA generates the alarmone (p)ppGpp under amino acid starvation, whereas SpoT is responsible for (p)ppGpp hydrolysis and for synthesis of (p)ppGpp under a variety of cellular stress conditions. It is widely accepted that RelA is associated...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.00315-07
更新日期:2007-09-01 00:00:00
abstract::Lactobacillus pentosus MP-10 was isolated from brines of naturally fermented Aloreña green table olives. MP-10 has potential probiotic traits, including inhibition of human pathogenic bacteria, survival at low pH (1.5), and bile salt tolerance (3%). Here, we report for the first time the annotated genome sequence of L...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.05171-11
更新日期:2011-09-01 00:00:00
abstract::Levin, Alfred P. (The Johns Hopkins University, Baltimore, Md.), and Philip E. Hartman. Action of a histidine analogue, 1,2,4-triazole-3-alanine, in Salmonella typhimurium. J. Bacteriol. 86:820-828. 1963.-The effect of the histidine analogue, 1,2,4-triazole-3-alanine (TRA), on growth and enzyme synthesis in histidine ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.86.4.820-828.1963
更新日期:1963-10-01 00:00:00
abstract::Biphenyl metabolism in Aspergillus toxicarius occurs by successive hydroxylations in the 4- and 4'-positions, followed by conjugation with sulfate to produce 4-hydroxybiphenyl-O-sulfonic acid and 4,4'-dihydroxybiphenyl-O-sulfonic acid. The hydroxylation reactions normally occur only after a prolonged lag period after ...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.156.1.49-57.1983
更新日期:1983-10-01 00:00:00
abstract::Sphingobium japonicum UT26 utilizes gamma-hexachlorocyclohexane (gamma-HCH) as its sole source of carbon and energy. In our previous studies, we cloned and characterized genes encoding enzymes for the conversion of gamma-HCH to beta-ketoadipate in UT26. In this study, we analyzed a mutant obtained by transposon mutage...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.01883-06
更新日期:2007-05-01 00:00:00
abstract::The brucellae are the etiological agents of brucellosis, a worldwide-distributed zoonosis. These bacteria are facultative intracellular parasites and thus are able to adjust their metabolism to the extra- and intracellular environments encountered during an infectious cycle. However, this aspect of Brucella biology is...
journal_title:Journal of bacteriology
pub_type: 杂志文章
doi:10.1128/JB.01663-14
更新日期:2014-08-15 00:00:00