Carol R. Lauzon
California State University
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Featured researches published by Carol R. Lauzon.
Current Microbiology | 2004
Blake Bextine; Carol R. Lauzon; Sarah Potter; David J. Lampe; Thomas A. Miller
An artificial feeding system was designed for the glassy-winged sharpshooter (GWSS), Homalodisca coagulata Say (Hemiptera: Cicadellidae). The system, unlike previous systems, provided enough nutrients to GWSS to survive for 48 h. A system like this is a prerequisite to examining the potential use of paratransgenesis to interrupt transmission of Xylella fastidiosa, the bacterial pathogen causing Pierce’s disease of grape, by insect vectors. We developed a system for short-term feeding of GWSS that allows for the introduction of bacteria in liquid medium, and we have demonstrated the ability of Alcaligenes xylosoxidans denitrificans, expressing a red fluorescent protein (dsRed), to colonize the cibarial region of the GWSS foregut for up to 5 weeks post-exposure. Alcaligenes xylosoxidans denitrificans thus occupies the same region in the foregut as the pathogen, Xylella fastidiosa.
Journal of Microbiological Methods | 2011
Andrew Lin; Lam Nguyen; Teresa Lee; Laurie M. Clotilde; Julie Ann Kase; Insook Son; J. Mark Carter; Carol R. Lauzon
Identification and serotyping of Shiga toxin-producing Escherichia coli during foodborne outbreaks can aid in matching clinical, food, and environmental isolates when trying to identify the source of illness and ultimately food contamination. Herein we describe a Luminex microbead-based suspension array to identify the O serogroup of the ten most clinically relevant STECs: O26, O45, O91, O103, O111, O113, O121, O128, O145, and O157. The use of PCR followed by Luminex xMAP® technology enables the detection of multiple analytes in a single multiplex reaction with high throughput capabilities. One hundred and fourteen STEC isolates were correctly identified with no false positives among forty-six other organisms using this assay. Assay performance was tested in multiple laboratories using a panel of eleven different STEC serogroups on the Bio-Plex 200 and MAGPIX instruments. The STEC microbead-based suspension array can be performed in a 96-well plate format for high throughput screening in less than 4h. Furthermore, it is expandable, allowing for the addition of O serogroups should the need arise.
Food Microbiology | 2011
Andrew Lin; Omar Sultan; Henry K. Lau; Evelyn Wong; Gary L. Hartman; Carol R. Lauzon
TaqMan™ real time PCR assays were designed for each of the non-O157 STEC O serogroups most commonly associated with human illness: O26, O45, O91, O103, O111, O113, O121, O128, and O145. The nine RT-PCR assays can be run as single assays when a known pathogen is of concern, or multiplexed in three reactions, to quickly screen for the most clinically relevant O serogroups. All assays included an internal amplification control constructed from the green fluorescent protein gene as an indicator of PCR inhibition. Of 103 strains tested, the inclusive tests accurately identified the O serogroup for 101 strains. The exclusive tests for each assay yielded no false positives for over 120 Escherichia coli strains and 23 non-E. coli bacteria tested. Furthermore, the RT-PCR assays were tested by inoculating four food matrices, milk, apple juice, lettuce, and ground beef, at ≤30 CFU/25 g or mL. Following a 24h selective enrichment, the RT-PCR assays detected STECs in all foods except for one ground beef sample inoculated with O111, and all apple juice samples inoculated with O113. The assays could also detect each O serogroup in human stool specimens inoculated with STECs at 1000 CFU/0.5 g of stool following 24 h enrichment.
Environmental Entomology | 2003
Carol R. Lauzon; Sarah Potter; Ronald J. Prokopy
Abstract Phloridzin, a plant-derived compound toxic to Rhagoletis pomonella (Walsh), the apple maggot fly, was degraded and detoxified by the bacterium Enterobacter agglomerans. Spectrophotometric and thin-layer chromatography data showed that E. agglomerans begins to use the glycoside in aqueous solution after 6 h of incubation at 24°C. All apple maggot flies that fed on three different concentrations of sterilized phloridzin solutions died within 24 h. Incubation of E. agglomerans in 0.001 and 0.01 M aqueous phloridzin for 3 d eliminated toxicity for apple maggot flies but most died after being fed a 1 M solution. Plant leachate containing phenolic compounds extracted from McIntosh apple leaves also was used by E. agglomerans. Enterobacter agglomerans entered logarithmic growth more quickly in leachate samples than in solutions of commercially-purified phloridzin. Protein, amino acid, and reducing sugar content of the leachate increased after incubation with E. agglomerans for 12 h. Reducing sugar content decreased, however, after 24 h of incubation, whereas protein and amino acid content continued to increase. Scanning electron micrographs of leachate intact on apple leaf surfaces revealed the presence of healthy rod-shaped bacteria and yeast aggregating about it. These images suggest that phylloplane microorganisms use leachate as a source of nutrients and this activity may affect the potency of plant defensive chemicals. The potential benefits afforded by the catabolic activities of phylloplane and/or gut microorganisms on plant compounds to apple maggot flies are discussed.
Current Microbiology | 2005
Blake Bextine; David J. Lampe; Carol R. Lauzon; Brian Jackson; Thomas A. Miller
Alcaligenes xylosoxidans subsp. denitrificans, originally isolated from the cibarial region of the foregut of the glassy-winged sharpshooter (Homalodisca coagulata), was transformed using the Himar1 transposition system to express EGFP. Seedlings of six potential host plants were inoculated with transformed bacteria and 2 weeks later samples were taken 5 cm away and analyzed by quantitative real-time PCR using primers designed to amplify the gene insert. The largest colony of 3,591,427 cells/2 cm of A. xylosoxidans subsp. denitrificans was found in Citrus limon, with almost all plants testing positive in both trials. The amount of colonization decreased in the other plants tested in the following order: orange (Citrus sinensis “sweet orange”) > chrysanthemum (Chrysanthemum grandiflora cv. “White Diamond”) > periwinkle (Vinca rosea) > crepe myrtle (Lagerstroemia indica) > grapevine (Vitis vinifera cv. Chardonnay). The bacterium’s preference for citrus paralleled the host insect’s preference for this same plant. Additional tests determined that A. xylosoxidans subsp. denitrificans thrives as a nonpathogenic, xylem-associated endophyte.
Applied and Environmental Microbiology | 2013
Yael Aharon; Zohar Pasternak; Michael Ben Yosef; Adi Behar; Carol R. Lauzon; Boaz Yuval; Edouard Jurkevitch
ABSTRACT The Mediterranean fruit fly (medfly) (Ceratitis capitata) lays eggs in fruits, where larvae subsequently develop, causing large-scale agricultural damage. Within its digestive tract, the fly supports an extended bacterial community that is composed of multiple strains of a variety of enterobacterial species. Most of these bacteria appear to be functionally redundant, with most strains sustaining diazotrophy and/or pectinolysis. At least some of these bacteria were shown to be vertically inherited, but colonization, structural, and metabolic aspects of the communitys dynamics have not been investigated. We used fluorescent in situ hybridization, metabolic profiling, plate cultures, and pyrosequencing to show that an initial, egg-borne, diverse community expands throughout the flys life cycle. While keeping “core” diazotrophic and pectinolytic functions, it also harbors diverse and fluctuating populations that express varied metabolic capabilities. We suggest that the metabolic and compositional plasticity of the flys microbiota provides potential adaptive advantages to the medfly host and that its acquisition and dynamics are affected by mixed processes that include stochastic effects, host behavior, and molecular barriers.
Journal of Chemical Ecology | 2004
David C. Robacker; Carol R. Lauzon; Xiaodun He
We investigated two strains of uricase (+) Enterobacter agglomerans, one isolated from the apple maggot fly (AMF) and one from the Mexican fruit fly (MFF), for 1) attractiveness to MFF, and 2) production of attractive chemicals. Regarding chemicals demonstrated attractive to the MFF, the MFF bacterial strain produced more 2,5-dimethylpyrazine, 2-phenylethanol, and indole than the AMF strain, whereas the AMF, but not the MFF strain, produced 3-hydroxybutanone. Cell types that predominated in plated subcultures varied from batch to batch resulting in variation in volatiles production, especially by the AMF strain where indole was sometimes a major component of the odor and at other times not detectable. Despite the greater production of attractive chemicals by the MFF strain, the AMF strain was consistently more attractive and the MFF strain was not different from uninoculated control plates. Statistical analyses indicated negative correlations of attractiveness with production of indole, 2,5-dimethylpyrazine, and 2-phenylethanol, and positive correlation with 3-hydroxybutanone. Results support previous findings with the Mexican fruit fly that showed combinations of attractive chemicals sometimes are not attractive.
Journal of Chemical Ecology | 2002
David C. Robacker; Carol R. Lauzon
We investigated two strains of Enterobacter agglomerans that differ in their ability to metabolize uric acid for (1) attractiveness to sugar-fed Mexican fruit flies, and (2) production of volatile chemicals that may be responsible for the attractiveness. The two strains were cultured on a medium that contained uric acid as the primary nitrogen source to simulate bird feces, a natural substrate for this bacterium. Active cultures of both strains were more attractive than uninoculated uric acid medium to both sexes of sugar-fed flies in wind-tunnel bioassays. The uricase(+) strain was more attractive than the uricase(−) strain to males and to females <9 days old, but not to older females. Volatiles found by solid-phase microextraction in greater amounts in headspace above active cultures of both strains than above uninoculated medium were ammonia, dimethyldisulfide, 3-methylbutanol, 2-phenylethanol, 2,5-dimethylpyrazine, and trimethylpyrazine. The uricase(+) strain produced more ammonia, dimethyldisulfide, and trimethylpyrazine than the uricase(−) strain. An additional chemical, 3-hydroxybutanone, appears to be produced exclusively by the uricase(+) strain. The uricase(−) strain produced more 2-phenylethanol than the uricase(+) strain. Differences in volatiles are consistent with the generally greater attractiveness of the uricase(+) strain compared with the uricase(−) strain as ammonia, 3-hydroxybutanone, and trimethylpyrazine have been demonstrated attractive to sugar-fed Mexican fruit flies.
Journal of Pest Science | 2012
Carol R. Lauzon; Sarah Potter
Midguts from adult sterile male Ceratitis capitata Wiedemann and Anastrepha ludens Loew, the Mediterranean fruit fly and Mexican fruit fly, respectively, were examined microscopically to determine if radiation used in sterile insect technique (SIT) affected this non target tissue and/or the microorganisms associated with the midgut. Scanning and transmission electron microscopy were used to compare midgut tissues and microorganisms from irradiated and nonirradiated mass-reared adult flies. Observations for both fruit fly species were similar. Our comparisons revealed that newly emerged and two-day-old irradiated flies exhibited signs of damage to midgut tissue, cellular organelles, and gut microbiota not observed in nonirradiated flies of the same ages. Peritrophic membrane formation and bacterial growth appeared diminished in the midguts of irradiated flies compared to nonirradiated flies. Cellular damage of midgut tissue from irradiated flies included distorted, small nuclei that lacked nuclear material, and mitochondria that were dilated and/or vacuolated. No visual evidence of cellular damage was observed in nonirradiated flies. The impact of radiation used in SIT on fly competitiveness, referred to herein as the capability of adult flies to perform a function, is discussed, including the potential use of probiotic diets to improve damaged midgut tissue and restore midgut microbiota.
Florida Entomologist | 1997
Nancy D. Epsky; Barbara D. Dueben; Robert R. Heath; Carol R. Lauzon; Ronald J. Prokopy
Flight tunnel bioassays confirmed attraction of female Caribbean fruit flies, Anastrepha suspensa (Loew), to volatiles from aqueous solutions of avian fecal material and methanol extracts of avian fecal material. Attraction was highest to freshly prepared and 72-h-old solutions of crude material. In direct comparisons between aqueous solutions of crude material and weight-equivalent amounts of methanol extract, more females were captured in response to volatiles from crude material in tests of 0-, 24- and 72-h-old solutions. Ammonia release rate was greater from the crude material than from the methanol extract in tests of 0-, 24- and 48-h-old solutions, The greatest amount (? sd) of ammonia was released from freshly prepared aqueous solutions of crude material (777 ? 250 .tg/h from 75 mg of crude material) but dropped within 24 h (288 ? 96 jtg/h from 75 mg of crude material) and then stayed close to that level. The greatest amount of ammonia released from methanol extracts was obtained from freshly prepared solutions (229 ? 70 pg/h from 75 mg crude material weight equivalent), also dropped within 24 h (98 ? 12 jg/h from 75 mg crude material weight equivalent) and then stayed fairly constant. Numbers of flies captured by either solution were directly correlated with ammonia release within the first 48 h of testing only, indicating that ammonia was partially or wholly responsible for attraction to the crude material during the first 48 h of testing. An increase in capture of females by volatiles from avian fecal material after 72 h in aqueous solution, which was observed in all tests, indicates that some chemical(s), other than ammonia, remain to be identified that are involved in fruit fly attraction.