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1.
Mutation of Candida tropicalis by Irradiation with a He-Ne Laser To Increase Its Ability To Degrade Phenol 总被引:1,自引:0,他引:1
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Yan Jiang Jianping Wen Xiaoqiang Jia Qinggele Caiyin Zongding Hu 《Applied microbiology》2007,73(1):226-231
Candida tropicalis isolated from acclimated activated sludge was used in this study. Cell suspensions with 5 × 107 cells ml−1 were irradiated by using a He-Ne laser. After mutagenesis, the irradiated cell suspension was diluted and plated on yeast extract-peptone-dextrose (YEPD) medium. Plates with approximately 20 individual colonies were selected, and all individual colonies were harvested for phenol biodegradation. The phenol biodegradation stabilities for 70 phenol biodegradation-positive mutants, mutant strains CTM 1 to 70, ranked according to their original phenol biodegradation potentials, were tested continuously during transfers. Finally, mutant strain CTM 2, which degraded 2,600 mg liter−1 phenol within 70.5 h, was obtained on the basis of its capacity and hereditary stability for phenol biodegradation. The phenol hydroxylase gene sequences were cloned in wild and mutant strains. The results showed that four amino acids were mutated by irradiation with a laser. In order to compare the activity of phenol hydroxylase in wild and mutant strains, their genes were expressed in Escherichia coli BL21(DE3) and enzyme activities were spectrophotometrically determined. It was clear that the activity of phenol hydroxylase was promoted after irradiation with a He-Ne laser. In addition, the cell growth and intrinsic phenol biodegradation kinetics of mutant strain CTM 2 in batch cultures were also described by Haldane's kinetic equation with a wide range of initial phenol concentrations from 0 to 2,600 mg liter−1. The specific growth and degradation rates further demonstrated that the CTM 2 mutant strain possessed a higher capacity to resist phenol toxicity than wild C. tropicalis did. 相似文献
2.
Lisa Jacobsen Lisa Durso Tyrell Conway Kenneth W. Nickerson 《Applied and environmental microbiology》2009,75(13):4633-4635
Escherichia coli isolates (72 commensal and 10 O157:H7 isolates) were compared with regard to physiological and growth parameters related to their ability to survive and persist in the gastrointestinal tract and found to be similar. We propose that nonhuman hosts in E. coli O157:H7 strains function similarly to other E. coli strains in regard to attributes relevant to gastrointestinal colonization.Escherichia coli is well known for its ecological versatility (15). A life cycle which includes both gastrointestinal and environmental stages has been stressed by both Savageau (15) and Adamowicz et al. (1). The gastrointestinal stage would be subjected to acid and detergent stress. The environmental stage is implicit in E. coli having transport systems for fungal siderophores (4) as well as pyrroloquinoline quinone-dependent periplasmic glucose utilization (1) because their presence indicates evolution in a location containing fungal siderophores and pyrroloquinoline quinone (1).Since its recognition as a food-borne pathogen, there have been numerous outbreaks of food-borne infection due to E. coli O157:H7, in both ground beef and vegetable crops (6, 13). Cattle are widely considered to be the primary reservoir of E. coli O157:H7 (14), but E. coli O157:H7 does not appear to cause disease in cattle. To what extent is E. coli O157:H7 physiologically unique compared to the other naturally occurring E. coli strains? We feel that the uniqueness of E. coli O157:H7 should be evaluated against a backdrop of other wild-type E. coli strains, and in this regard, we chose the 72-strain ECOR reference collection originally described by Ochman and Selander (10). These strains were chosen from a collection of 2,600 E. coli isolates to provide diversity with regard to host species, geographical distribution, and electromorph profiles at 11 enzyme loci (10).In our study we compared the 72 strains of the ECOR collection against 10 strains of E. coli O157:H7 and six strains of E. coli which had been in laboratory use for many years (Table (Table1).1). The in vitro comparisons were made with regard to factors potentially relevant to the bacteria''s ability to colonize animal guts, i.e., acid tolerance, detergent tolerance, and the presence of the Entner-Doudoroff (ED) pathway (Table (Table2).2). Our longstanding interest in the ED pathway (11) derives in part from work by Paul Cohen''s group (16, 17) showing that the ED pathway is important for E. coli colonization of the mouse large intestine. Growth was assessed by replica plating 88 strains of E. coli under 40 conditions (Table (Table2).2). These included two LB controls (aerobic and anaerobic), 14 for detergent stress (sodium dodecyl sulfate [SDS], hexadecyltrimethylammonium bromide [CTAB], and benzalkonium chloride, both aerobic and anaerobic), 16 for acid stress (pH 6.5, 6.0, 5.0, 4.6, 4.3, 4.2, 4.1, and 4.0), four for the ability to grow in a defined minimal medium (M63 glucose salts with and without thiamine), and four for the presence or absence of a functional ED pathway (M63 with gluconate or glucuronate). All tests were done with duplicate plates in two or three separate trials. The data are available in Tables S1 to S14 in the supplemental material, and they are summarized in Table Table22.
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Open in a separate windowaEight LB controls were run, two for each set of LB experiments: SDS, CTAB, benzalkonium chloride (BAC), and pH stress.bGrowth was measured as either +++, +, or 0 (good, poor, and none, respectively), with +++ being the growth achieved on the LB control plates. “Variable” means that two or three replicates did not agree. All experiments were done at 37°C.c“Anaerobic” refers to use of an Oxoid anaerobic chamber. Aerobic and anaerobic growth data are presented together when the results were identical and separately when the results were not the same or the anaerobic set had not been done. LB plates were measured after 1 (aerobic) or 2 (anaerobic) days, and the M63 plates were measured after 2 or 3 days.dCTAB used at 0.05, 0.2%, and 0.4%.eM63 defined medium (3) was supplemented with glucose, gluconate, or glucuronate, all at 0.2%.fIdentical results were obtained with and without 0.0001% thiamine.gND, not determined. 相似文献
TABLE 1.
E. coli strains used in this studyE. coli strain (n) | Source |
---|---|
ECOR strains (72) | Thomas Whittman |
Laboratory adapted (6) | |
K-12 Davis | Paul Blum |
CG5C 4401 | Paul Blum |
K-12 Stanford | Paul Blum |
W3110 | Paul Blum |
B | Tyler Kokjohn |
AB 1157 | Tyler Kokjohn |
O157:H7 (10) | |
FRIK 528 | Andrew Benson |
ATCC 43895 | Andrew Benson |
MC 1061 | Andrew Benson |
C536 | Tim Cebula |
C503 | Tim Cebula |
C535 | Tim Cebula |
ATCC 43889 | William Cray, Jr. |
ATCC 43890 | William Cray, Jr. |
ATCC 43888 | Willaim Cray, Jr. |
ATCC 43894 | William Cray, Jr. |
TABLE 2.
Physiological comparison of 88 strains of Escherichia coliGrowth medium or condition | Oxygenc | No. of strains with type of growthb
| |||||||||||
---|---|---|---|---|---|---|---|---|---|---|---|---|---|
ECOR strains (n = 72)
| Laboratory strains (n = 6)
| O157:H7 strains (n = 10)
| |||||||||||
Good | Poor | None | Variable | Good | Poor | None | Variable | Good | Poor | None | Variable | ||
LB controla | Both | 72 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 10 | 0 | 0 | 0 |
1% SDS | Aerobic | 69 | 3 | 0 | 0 | 6 | 0 | 0 | 0 | 8 | 0 | 0 | 2 |
5% SDS | Aerobic | 68 | 4 | 0 | 0 | 6 | 0 | 0 | 0 | 8 | 2 | 0 | 0 |
1% SDS | Anaerobic | 53 | 15 | 4 | 0 | 2 | 3 | 1 | 0 | 1 | 7 | 0 | 2 |
5% SDS | Anaerobic | 0 | 68 | 4 | 0 | 0 | 4 | 2 | 0 | 0 | 7 | 0 | 4 |
CTABd (all) | Both | 0 | 0 | 72 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 10 | 0 |
0.05% BAC | Aerobic | 3 | 11 | 58 | 2 | 0 | 2 | 2 | 2 | 0 | 0 | 9 | 1 |
0.2% BAC | Aerobic | 0 | 1 | 71 | 0 | 1 | 0 | 5 | 0 | 0 | 0 | 10 | 0 |
0.05% BAC | Anaerobic | 2 | 3 | 67 | 0 | 0 | 1 | 5 | 0 | 0 | 0 | 9 | 1 |
0.2% BAC | Anaerobic | 0 | 0 | 72 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 10 | 0 |
pH 6.5 | Both | 72 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 10 | 0 | 0 | 0 |
pH 6 | Both | 72 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 10 | 0 | 0 | 0 |
pH 5 | Both | 70 | 2 | 0 | 0 | 6 | 0 | 0 | 0 | 9 | 0 | 0 | 1 |
pH 4.6 | Both | 70 | 2 | 0 | 0 | 6 | 0 | 0 | 0 | 10 | 0 | 0 | 0 |
pH 4.3 | Aerobic | 14 | 0 | 1 | 57 | 3 | 1 | 2 | 0 | 3 | 2 | 0 | 5 |
pH 4.3 | Anaerobic | 69 | 3 | 0 | 0 | 3 | 1 | 2 | 0 | 1 | 1 | 0 | 0 |
pH 4.1 or 4.2 | Aerobic | 0 | 0 | 72 | 0 | NDg | ND | ||||||
pH 4.0 | Both | 0 | 0 | 72 | 0 | 0 | 0 | 6 | 0 | 0 | 0 | 9 | 1 |
M63 with supplemente | |||||||||||||
Glucose | Aerobicf | 69 | 1 | 2 | 0 | 5 | 0 | 1 | 0 | 9 | 0 | 1 | 0 |
Glucose | Anaerobicf | 70 | 0 | 2 | 0 | 5 | 0 | 1 | 0 | 9 | 0 | 1 | 0 |
Gluconate | Both | 69 | 1 | 2 | 0 | 5 | 0 | 1 | 0 | 9 | 0 | 1 | 0 |
Glucuronate | Aerobic | 68 | 2 | 2 | 0 | 5 | 0 | 1 | 0 | 9 | 0 | 1 | 0 |
Glucuronate | Anaerobic | 69 | 1 | 2 | 0 | 5 | 0 | 1 | 0 | 9 | 0 | 1 | 0 |
3.
The larval endoparasitoid, Neochrysocharis formosa (Westwood), is an important natural enemy of the leafminer Liriomyza trifolii (Burgess) in Japan. The thelytokous strain of N. formosa mostly produces female progeny. Male progeny were produced by females treated with tetracycline, suggesting that microorganisms
induce thelytoky in N. formosa. The result of nucleotide sequencing of the 16S rRNA gene indicated that the parasitoid is infected with a Rickettsia bacterium, which appears to be causative of the thelytoky. Although Rickettsia-bellii-like bacteria have been found to be associated with various reproductive disorders, this is the first finding of a parthenogenesis-inducing
Rickettsia among insects. 相似文献
4.
Neil Parkinson Ruth Bryant Janice Bew Christine Conyers Robert Stones Michael Alcock John Elphinstone 《Applied and environmental microbiology》2013,79(19):6016-6022
Variable-number tandem-repeat (VNTR) analysis was used for high-resolution discrimination among Ralstonia solanacearum phylotype IIB sequevar 1 (PIIB-1) isolates and further evaluated for use in source tracing. Five tandem-repeat-containing loci (comprising six tandem repeats) discriminated 17 different VNTR profiles among 75 isolates from potato, geranium, bittersweet (Solanum dulcamara), tomato, and the environment. R. solanacearum isolates from crops at three unrelated outbreak sites where river water had been used for irrigation had distinct VNTR profiles that were shared with PIIB-1 isolates from infected bittersweet growing upriver of each site. The VNTR profiling results supported the implication that the source of R. solanacearum at each outbreak was contaminated river water. Analysis of 51 isolates from bittersweet growing in river water at different locations provided a means to evaluate the technique for studying the epidemiology of the pathogen in the environment. Ten different VNTR profiles were identified among bittersweet PIIB-1 isolates from the River Thames. Repeated findings of contiguous river stretches that produced isolates that shared single VNTR profiles supported the hypothesis that the pathogen had disseminated from infected bittersweet plants located upriver. VNTR profiles shared between bittersweet isolates from two widely separated Thames tributaries (River Ray and River Colne) suggested they were independently contaminated with the same clonal type. Some bittersweet isolates had VNTR profiles that were shared with potato isolates collected outside the United Kingdom. It was concluded that VNTR profiling could contribute to further understanding of R. solanacearum epidemiology and assist in control of future disease outbreaks. 相似文献
5.
6.
Yoshitaka Yamazaki Lia Danelishvili Martin Wu Molly MacNab Luiz E. Bermudez 《Applied microbiology》2006,72(1):819-825
Mycobacterium avium is widely distributed in the environment, and it is chiefly found in water and soil. M. avium, as well as Mycobacterium smegmatis, has been recognized to produce a biofilm or biofilm-like structure. We screened an M. avium green fluorescent protein (GFP) promoter library in M. smegmatis for genes involved in biofilm formation on polyvinyl chloride (PVC) plates. Clones associated with increased GFP expression ≥2.0-fold over the baseline were sequenced. Seventeen genes, most encoding proteins of the tricarboxylic acid (TCA) cycle and GDP-mannose and fatty acid biosynthesis, were identified. Their regulation in M. avium was confirmed by examining the expression of a set of genes by real-time PCR after incubation on PVC plates. In addition, screening of 2,000 clones of a transposon mutant bank constructed using M. avium strain A5, a mycobacterial strain with the ability to produce large amounts of biofilm, revealed four mutants with an impaired ability to form biofilm. Genes interrupted by transposons were homologues of M. tuberculosis 6-oxodehydrogenase (sucA), enzymes of the TCA cycle, protein synthetase (pstB), enzymes of glycopeptidolipid (GPL) synthesis, and Rv1565c (a hypothetical membrane protein). In conclusion, it appears that GPL biosynthesis, including the GDP-mannose biosynthesis pathway, is the most important pathway involved in the production of M. avium biofilm. 相似文献
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9.
Construction of Streptococcus lactis subsp. lactis Strains with a Single Plasmid Associated with Mucoid Phenotype 总被引:2,自引:1,他引:1
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Lactose-fermenting mucoid (Lac+ Muc+) variants of plasmid-free Streptococcus lactis subsp. lactis MG1614 were obtained by protoplast transformation with total plasmid DNA from Muc+S. lactis subsp. cremoris ARH87. By using plasmid DNA from these variants for further transformations followed by novobiocininduced plasmid curing, Lac− Muc+ MG1614 strains containing only a single 30-megadalton plasmid could be constructed. This plasmid, designated pVS5, appeared to be associated with the Muc+ phenotype. 相似文献
10.
Occurrence and Phenotypic Characterization of Yersinia ruckeri Strains with Biofilm-Forming Capacity in a Rainbow Trout Farm
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L. Coquet P. Cosette L. Quillet F. Petit G.-A. Junter T. Jouenne 《Applied microbiology》2002,68(2):470-475
The presence of Yersinia ruckeri in a French fish farm was investigated. Y. ruckeri was isolated mainly from algae and sediment samples rather than from water. Twenty-two Y. ruckeri isolates were obtained, and three strains were distinguished by enterobacterial repetitive intergenic consensus PCR amplification. These strains were able to adhere to solid supports. This characteristic was correlated with flagellum-mediated motility. Killing experiments showed that sessile cells were more resistant to oxolinic acid than their planktonic counterparts. Our results demonstrate that surface colonization of fish farm tanks by Y. ruckeri biofilms is a potential source of recurrent infection for extended periods of time. 相似文献
11.
Oligonucleotide Probes That Hybridize with rRNA as a Tool To Study Frankia Strains in Root Nodules 总被引:1,自引:3,他引:1
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Dittmar Hahn Marjo J. C. Starrenburg Antoon D. L. Akkermans 《Applied microbiology》1990,56(5):1342-1346
Oligonucleotide probes that hybridize with specific sequences in variable regions of the 16S rRNA of the nitrogen-fixing actinomycete Frankia were used for the identification of Frankia strains in nodules. Frankia cells were released from plant tissue by grinding glutaraldehyde-fixed root nodules in guanidine hydrochloride solution. rRNA was obtained after sonication, precipitation with ethanol, and purification by phenolchloroform extraction. Degradation of rRNA, evident in Northern blots, did not affect hybridization with the oligonucleotides. Nodules of about 1 mg (fresh weight) provided sufficient rRNA for reliable detection of the Frankia strain. The utility of this rRNA extraction method was tested in a competition experiment between two effective Frankia strains on cloned Alnus glutinosa plants. 相似文献
12.
P Laksanalamai LA Joseph BJ Silk LS Burall C L Tarr P Gerner-Smidt AR Datta 《PloS one》2012,7(7):e42448
A multistate listeriosis outbreak associated with cantaloupe consumption was reported in the United States in September, 2011. The outbreak investigation recorded a total of 146 invasive illnesses, 30 deaths and one miscarriage. Subtyping of the outbreak associated clinical, food and environmental isolates revealed two serotypes (1/2a and 1/2b) and four pulsed-field gel electrophoresis two-enzyme pattern combinations I, II, III, and IV, including one rarely seen before this outbreak. A DNA-microarray, Listeria GeneChip®, developed by FDA from 24 Listeria monocytogenes genome sequences, was used to further characterize a representative sample of the outbreak isolates. The microarray data (in the form of present or absent calls of specific DNA sequences) separated the isolates into two distinct groups as per their serotypes. The gene content of the outbreak-associated isolates was distinct from that of the previously-reported outbreak strains belonging to the same serotypes. Although the 1/2b outbreak associated isolates are closely related to each other, the 1/2a isolates could be further divided into two distinct genomic groups, one represented by pattern combination I strains and the other represented by highly similar pattern combinations III and IV strains. Gene content analysis of these groups revealed unique genomic sequences associated with these two 1/2a genovars. This work underscores the utility of multiple approaches, such as serotyping, PFGE and DNA microarray analysis to characterize the composition of complex polyclonal listeriosis outbreaks. 相似文献
13.
Insect‐microbial symbioses have vast biochemical diversity, which is beneficial to produce bioactive secondary metabolites. In this study, chemical examination of a Streptomyces sp. associated with a mud dauber wasp led to the isolation of fourteen compounds. Their structures were determined by spectroscopic methods and comparison with literature data. Among the isolates, compounds 1,2,3‐benzotriazin‐4(1H)‐one and 4‐(2‐aminoethyl)phenyl acetate were first reported from this species. Bioactivities of the isolated compounds were assayed for the first time against hexokinase II. 4‐(2‐Aminoethyl)phenyl acetate, germicidin B, phenylacetic acid, isogermicidin A and germicidin C displayed significant inhibitory activity against hexokinase II, with the IC50 values of 5.11, 7.11, 7.15, 8.45 and 8.78 μM, respectively. 相似文献
14.
Identification of Escherichia coli O157:H7 Genomic Regions Conserved in Strains with a Genotype Associated with Human Infection 总被引:1,自引:0,他引:1
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Marina Steele Kim Ziebell Yongxiang Zhang Andrew Benson Paulina Konczy Roger Johnson Victor Gannon 《Applied microbiology》2007,73(1):22-31
Beta-glucuronidase-negative, sorbitol-nonfermenting isolates of Shiga toxin-producing Escherichia coli O157 comprise part of a clone complex of related enterohemorrhagic E. coli isolates. High-resolution genotyping shows that the O157 populations have diverged into two different lineages that appear to have different ecologies. To identify genomic regions unique to the most common human-associated genotype, suppression subtractive hybridization was used to identify DNA sequences present in two clinical strains representing the human lineage I O157:H7 strains but absent from two bovine-derived lineage II strains. PCR assays were then used to test for the presence of these regions in 10 lineage I strains and 20 lineage II strains. Twelve conserved regions of genomic difference for lineage I (CRDI) were identified that were each present in at least seven of the lineage I strains but absent in most of the lineage II strains tested. The boundaries of the lineage I conserved regions were further delimited by PCR. Eleven of these CRDI were associated with E. coli Sakai S-loops 14, 16, 69, 72, 78, 82, 83, 91 to 93, 153, and 286, and the final CRDI was located on the pO157 virulence plasmid. Several potential virulence factors were identified within these regions, including a putative hemolysin-activating protein, an iron transport system, and several possible regulatory genes. Cluster analysis based on lineage I conserved regions showed that the presence/absence of these regions was congruent with the inferred phylogeny of the strains. 相似文献
15.
Kouji Sakai Tomoki Yoshikawa Fumio Seki Shuetsu Fukushi Maino Tahara Noriyo Nagata Yasushi Ami Tetsuya Mizutani Ichiro Kurane Ryoji Yamaguchi Hideki Hasegawa Masayuki Saijo Katsuhiro Komase Shigeru Morikawa Makoto Takeda 《Journal of virology》2013,87(12):7170-7175
A canine distemper virus (CDV) strain, CYN07-dV, associated with a lethal outbreak in monkeys, used human signaling lymphocyte activation molecule as a receptor only poorly but readily adapted to use it following a P541S substitution in the hemagglutinin protein. Since CYN07-dV had an intrinsic ability to use human nectin-4, the adapted virus became able to use both human immune and epithelial cell receptors, as well as monkey and canine ones, suggesting that CDV can potentially infect humans. 相似文献
16.
17.
Cloning of a Streptococcus lactis subsp. lactis Chromosomal Fragment Associated with the Ability To Grow in Milk 总被引:7,自引:6,他引:1
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A chromosomal fragment of 6.7 megadaltons (MDa), apparently containing the genes for milk protein utilization by Streptococcus lactis subsp. lactis SSL135, was cloned in S. lactis subsp. lactis MG1614, a proteinase-negative strain. For the cloning, the chromosomal DNA of SSL135 was cleaved with restriction enzyme BamHI and the resulting fragments were ligated to the single BclI site of pVS2, a 3.3-MDa chloramphenicol-erythromycin double-resistance plasmid constructed in this laboratory. S. lactis subsp. lactis MG1614 was transformed by using this ligation mixture and selecting for chloramphenicol resistance and growth in citrated milk medium. One clone containing a 10.0-MDa plasmid, subsequently designated as pVS6, was chosen for further studies. Despite the lack of homology with previously characterized proteinase genes of lactic streptococci, the cloned insert consistently conveyed the ability to grow in milk to proteinase-negative recipients in repeated transformation experiments. The genetic evidence suggests that the main part of the gene(s) for the proposed proteinase activity is located within a 3.8-MDa BglII fragment of the clone. 相似文献
18.
Ying Bai David T. S. Hayman Clifton D. McKee Michael Y. Kosoy 《PLoS neglected tropical diseases》2015,9(1)
Bartonellae are facultative intracellular bacteria and are highly adapted to their mammalian host cell niches. Straw-colored fruit bats (Eidolon helvum) are commonly infected with several bartonella strains. To elucidate the genetic diversity of these bartonella strains, we analyzed 79 bartonella isolates from straw-colored fruit bats in seven countries across Africa (Cameroon, Annobon island of Equatorial Guinea, Ghana, Kenya, Nigeria, Tanzania, and Uganda) using a multi-locus sequencing typing (MLST) approach based on nucleotide sequences of eight loci (ftsZ, gltA, nuoG, ribC, rpoB, ssrA, ITS, and 16S rRNA). The analysis of each locus but ribC demonstrated clustering of the isolates into six genogroups (E1 – E5 and Ew), while ribC was absent in the isolates belonging to the genogroup Ew. In general, grouping of all isolates by each locus was mutually supportive; however, nuoG, gltA, and rpoB showed some incongruity with other loci in several strains, suggesting a possibility of recombination events, which were confirmed by network analyses and recombination/mutation rate ratio (r/m) estimations. The MLST scheme revealed 45 unique sequence types (ST1 – 45) among the analyzed bartonella isolates. Phylogenetic analysis of concatenated sequences supported the discrimination of six phylogenetic lineages (E1 – E5 and Ew) corresponding to separate and unique Bartonella species. One of the defined lineages, Ew, consisted of only two STs (ST1 and ST2), and comprised more than one-quarter of the analyzed isolates, while other lineages contained higher numbers of STs with a smaller number of isolates belonging to each lineage. The low number of allelic polymorphisms of isolates belonging to Ew suggests a more recent origin for this species. Our findings suggest that at least six Bartonella species are associated with straw-colored fruit bats, and that distinct STs can be found across the distribution of this bat species, including in populations of bats which are genetically distinct. 相似文献
19.
20.
Hiroyuki Sakai Miwa Takahara Naomi F. Honjo Shun'ichi Doi Norihiro Sadato Yuji Uchiyama 《PloS one》2012,7(9)
Although low executive functioning is a risk factor for vehicle crashes among elderly drivers, the neural basis of individual differences in this cognitive ability remains largely unknown. Here we aimed to examine regional frontal gray matter volume associated with executive functioning in normal aging individuals, using voxel-based morphometry (VBM). To this end, 39 community-dwelling elderly volunteers who drove a car on a daily basis participated in structural magnetic resonance imaging, and completed two questionnaires concerning executive functioning and risky driving tendencies in daily living. Consequently, we found that participants with low executive function capacity were prone to risky driving. Furthermore, VBM analysis revealed that lower executive function capacity was associated with smaller gray matter volume in the supplementary motor area (SMA). Thus, the current data suggest that SMA volume is a reliable predictor of individual differences in executive function capacity as a risk factor for vehicle crashes among elderly persons. The implication of our results is that regional frontal gray matter volume might underlie the variation in driving tendencies among elderly drivers. Therefore, detailed driving behavior assessments might be able to detect early neurodegenerative changes in the frontal lobe in normal aging adults. 相似文献