Poor Colonization Research Articles

Recombinant PorA, the Major Outer Membrane Protein ofCampylobacter jejuni, Provides Heterologous Protection in an Adult Mouse Intestinal Colonization Model

Immunity against Campylobacter jejuni, a major food-borne pathogen causing diarrhea, is largely serotype specific. The major outer membrane protein (MOMP) of C. jejuni, PorA, is a common antigen with the potential to provide broad protection. Adult BALB/c mice were orally immunized with a recombinant glutathione S-transferase (GST) fused to PorA prepared from Campylobacter jejuni C31 (O:6,7) (GST-PorA) combined with a modified heat-labile enterotoxin of Escherichia coli as an adjuvant and later orally challenged with C31 strain or three heterologous strains: 48 (O:19), 75 (O:3), and 111 (O:1,44). Protection from colonization with the challenge organism was studied by fecal screening daily for 9 days. Serum and intestinal lavage fluid antibodies against the vaccine and Sarkosyl-purified MOMP from C31 were measured by using an enzyme-linked immunosorbent assay. The vaccine produced robust antibody responses against both antigens in serum and secretion. Since strain C31 was a poor colonizer, homologous protection could not be studied. The protective efficacies of heterologous strains were 43% (for strain 48, P < 0.001), 29% (for strain 75, P < 0.005), and 42% (for strain 111, P < 0.001) for the 9-day period compared to control mice given phosphate-buffered saline. Thus, PorA provided appreciable protection against colonization with heterologous serotypes.

Herbivore and Fungal Pathogen Exclusion Affects the Seed Production of Four Common Grassland Species

Insect herbivores and fungal pathogens can independently affect plant fitness, and may have interactive effects. However, few studies have experimentally quantified the joint effects of insects and fungal pathogens on seed production in non-agricultural populations. We examined the factorial effects of insect herbivore exclusion (via insecticide) and fungal pathogen exclusion (via fungicide) on the population-level seed production of four common graminoid species (Andropogon gerardii, Schizachyrium scoparium, Poa pratensis, and Carex siccata) over two growing seasons in Minnesota, USA. We detected no interactive effects of herbivores and pathogens on seed production. However, the seed production of all four species was affected by either insecticide or fungicide in at least one year of the study. Insecticide consistently doubled the seed production of the historically most common species in the North American tallgrass prairie, A. gerardii (big bluestem). This is the first report of insect removal increasing seed production in this species. Insecticide increased A. gerardii number of seeds per seed head in one year, and mass per seed in both years, suggesting that consumption of flowers and seed embryos contributed to the effect on seed production. One of the primary insect species consuming A. gerardii flowers and seed embryos was likely the Cecidomyiid midge, Contarinia wattsi. Effects on all other plant species varied among years. Herbivores and pathogens likely reduce the dispersal and colonization ability of plants when they reduce seed output. Therefore, impacts on seed production of competitive dominant species may help to explain their relatively poor colonization abilities. Reduced seed output by dominant graminoids may thereby promote coexistence with subdominant species through competition-colonization tradeoffs.

A dual role of extracellular DNA during biofilm formation of Neisseria meningitidis

Major pathogenic clonal complexes (cc) of Neisseria meningitidis differ substantially in their point prevalence among healthy carriers. We show that frequently carried pathogenic cc (e.g. sequence type ST-41/44 cc and ST-32 cc) depend on extracellular DNA (eDNA) to initiate in vitro biofilm formation, whereas biofilm formation of cc with low point prevalence (ST-8 cc and ST-11 cc) was eDNA-independent. For initial biofilm formation, a ST-32 cc type strain, but not a ST-11 type strain, utilized eDNA. The release of eDNA was mediated by lytic transglycosylase and cytoplasmic N-acetylmuramyl-L-alanine amidase genes. In late biofilms, outer membrane phospholipase A-dependent autolysis, which was observed in most cc, but not in ST-8 and ST-11 strains, was required for shear force resistance of microcolonies. Taken together, N. meningitidis evolved two different biofilm formation strategies, an eDNA-dependent one yielding shear force resistant microcolonies, and an eDNA-independent one. Based on the experimental findings and previous epidemiological observations, we hypothesize that most meningococcal cc display a settler phenotype, which is eDNA-dependent and results in a stable interaction with the host. On the contrary, spreaders (ST-11 and ST-8 cc) are unable to use eDNA for biofilm formation and might compensate for poor colonization properties by high transmission rates.

Pre-cropping with canola decreased Pratylenchus thornei populations, arbuscular mycorrhizal fungi, and yield of wheat

Root-lesion nematode (Pratylenchus thornei) significantly reduces wheat yields in the northern Australian grain region. Canola is thought to have a ‘biofumigation’ potential to control nematodes; therefore, a field experiment was designed to compare canola with other winter crops or clean-fallow for reducing P. thornei population densities and improving growth of P. thornei-intolerant wheat (cv. Batavia) in the following year. Immediately after harvest of the first-year crops, populations of P. thornei were lowest following various canola cultivars or clean-fallow (1957–5200 P. thornei/kg dry soil) and were highest following susceptible wheat cultivars (31 033–41 294/kg dry soil). Unexpectedly, at planting of the second-year wheat crop, nematode populations were at more uniform lower levels (&lt;5000/kg dry soil), irrespective of the previous season’s treatment, and remained that way during the growing season, which was quite dry. Growth and grain yield of the second-year wheat crop were poorest on plots previously planted with canola or left fallow due to poor colonisation with arbuscular mycorrhizal (AM) fungi, with the exception of canola cv. Karoo, which had high AM fungal colonisation and low wheat yields. There were significant regressions between growth and yield parameters of the second-year wheat and levels of AMF following the pre-crop treatments. Thus, canola appears to be a good crop for reducing P. thornei populations, but AM fungal-dependence of subsequent crops should be considered, particularly in the northern Australian grain region.

The effect of cutting length on the rooting and growth of subtropical Eucalyptus hybrid clones in South Africa

The length of a cutting can affect both the rooting and plug colonisation of container-grown stock. Using hedges from conventional clonebanks established in the ground, four cutting length treatments (13, 10, 8 and 5 cm) were tested using five Eucalyptus grandis × E. urophylla clones. The smallest cutting length had the lowest rooting, number of leaves, number of roots per cutting, root dry mass, and shoot dry mass. Root plug colonisation (i.e. plug score) was greatest for a cutting length of 8 cm and lowest for the 5 cm cutting length (i.e. poor colonisation). It is recommended that cutting length should be approximately 8-10 cm for operational production.

English

&nbsp; The study investigated the degradation of the polycyclic aromatic hydrocarbons (PAH) benzo(a)anthracene, benzo(a) fluoranthene, benzo(a) pyrene, chrysene and phenanthrene in a soil that was sterilized and inoculated with the nonligninolytic fungi,&nbsp;Fusarium flocciferum&nbsp;and&nbsp;Trichoderma&nbsp;spp. and the ligninolytic fungi,Trametes versicolor&nbsp;and&nbsp;Pleurotus ostreatus&nbsp;in the presence of cadmium (Cd) and nickel (Ni) during a ten week incubation period. The soil pH was initially 5.3 and after amendment increased to 7.0. The fungi degraded the tested PAHs between 21 and 93% by the end of the tenth week. The fungi degraded the less-soluble PAHs containing five or six aromatic rings more slowly than those containing fewer aromatic rings. Although&nbsp;the presence of cadmium and nickel in the soil affected the activity of the enzymes produced by the fungi,&nbsp;no significant decrease in PAH degradation was found in the contaminated soil containing 50 or 100 mg kg-1&nbsp;of Cd and Ni. However, at 300 and 500&nbsp;mg kg-1, degradation of the PAHs by the fungi was impaired and the severity of the impairments increased with the increase in the concentrations of Cd and Ni. This was probably due&nbsp;to the lack of the activities of some enzymes such as Mn-dependent peroxidase, which could have resulted from the poor colonization of the fungi at these concentrations.&nbsp; &nbsp; Key words:&nbsp;Bioremediation, fungi, heavy metals, PAHs, soil.

Nested species subsets of amphibians and reptiles on Neotropical forest islands

AbstractNested species subsets are a common pattern of community assembly characteristic of many types of fragmented landscapes and insular systems. Here we describe nested subset patterns of amphibian and reptile occupancy on 23 forest islands in north‐eastern Bolivia. We used observed occupancy patterns to differentiate five distributional guilds: widespread species, rare species, poor colonizers, area‐sensitive species and supertramps. Amphibian occurrences were nested along a forest island isolation gradient, and when species from each of the distribution classes were removed from subsequent analyses of nestedness, we found that dispersal‐limited poor colonizers were responsible for the association between nestedness and isolation. Amphibians associated with the grassland matrix at the study site showed a nested pattern linked with area, although this pattern did not scale up to all amphibians and could not be unequivocally attributed to any of the distributional guilds we recognized. There were no strong associations between two biological characteristics, body size and relative abundance in the matrix, and the likelihood of occupancy along either forest island area or isolation gradients. The relative importance of isolation in shaping nested patterns of amphibians on these forest islands may be a result of either (1) the greater range in isolation values included in this study compared with many others; (2) the long time since isolation in this landscape, manifesting a footprint of isolation not apparent in more recently fragmented patches; (3) the relatively homogeneous grassland matrix surrounding forest islands that likely provides little refuge for animals moving among forest islands.

Capsule Endoscopy versus Colonoscopy for the Detection of Polyps and Cancer

An ingestible capsule consisting of an endoscope equipped with a video camera at both ends was designed to explore the colon. This study compared capsule endoscopy with optical colonoscopy for the detection of colorectal polyps and cancer. We performed a prospective, multicenter study comparing capsule endoscopy with optical colonoscopy (the standard for comparison) in a cohort of patients with known or suspected colonic disease for the detection of colorectal polyps or cancer. Patients underwent an adapted colon preparation, and colon cleanliness was graded from poor to excellent. We computed the sensitivity and specificity of capsule endoscopy for polyps, advanced adenoma, and cancer. A total of 328 patients (mean age, 58.6 years) were included in the study. The capsule was excreted within 10 hours after ingestion and before the end of the lifetime of the battery in 92.8% of the patients. The sensitivity and specificity of capsule endoscopy for detecting polyps that were 6 mm in size or bigger were 64% (95% confidence interval [CI], 59 to 72) and 84% (95% CI, 81 to 87), respectively, and for detecting advanced adenoma, the sensitivity and specificity were 73% (95% CI, 61 to 83) and 79% (95% CI, 77 to 81), respectively. Of 19 cancers detected by colonoscopy, 14 were detected by capsule endoscopy (sensitivity, 74%; 95% CI, 52 to 88). For all lesions, the sensitivity of capsule endoscopy was higher in patients with good or excellent colon cleanliness than in those with fair or poor colon cleanliness. Mild-to-moderate adverse events were reported in 26 patients (7.9%) and were mostly related to the colon preparation. The use of capsule endoscopy of the colon allows visualization of the colonic mucosa in most patients, but its sensitivity for detecting colonic lesions is low as compared with the use of optical colonoscopy. (ClinicalTrials.gov number, NCT00604162.)

Germination requirements and seed mass of slow- and fast- colonizing temperate forest herbs along a latitudinal gradient

Predictions on displacement of suitable habitats due to climate change suggest that plant species with poor colonization ability may be unable to move fast enough to match forecasted climate-induced changes in habitat distribution. However, studies on early Holocene plant migration show fast migration of many plant species that are poor colonizers today. We hypothesize that warmer temperatures during the early Holocene yielded higher seed quality, contributing to explaining the fast migration. We studied how the 3 seed quality variables, seed mass, germinability, and requirements for break of seed dormancy, vary for seeds of 11 forest herb species with varying colonization capacity collected along a 1400-km latitudinal gradient. Within species, seed mass showed a positive correlation with latitude, whereas germinability was more positively correlated with temperature (growing degree hours obtained at time of seed collection). Only slow-colonizing species increased germinability with temperature, whereas only fast-colonizing species increased germinability with latitude. These interactions were only detectable when analyzing germinability of the seeds, even though this trait and seed mass were correlated. The requirement for dormancy break did not correlate with latitude or temperature. The results indicate that seed development of slow colonizers may be favoured by a warmer climate, which in turn may be important for their migration capacity.

Ichnology of the Cretaceous Oceanic Red Beds (Outer Western Carpathians, Czech Republic)

Ichnology of the Cretaceous Oceanic Red Beds (Outer Western Carpathians, Czech Republic)Large differences in the intensity and overall character of bioturbational structures were found in five facies containing hemipelagic red beds. Red beds (CORB) of the Godula facies of the Silesian Unit and their equivalents (mostly not red) in the Kelč facies of the Silesian Unit and the CORB in the non-calcareous sediments of the Rača Unit display a very low degree of bioturbation. The CORB facies of the Rača Unit, containing calcareous intercalations, displays a very high degree of bioturbation as expressed by a high ichnofabric index. They contain trace fossilsChondrites, Zoophycos, Planolites, Thalassinoides, Palaeophycus, TeichichnusandPhycosiphon.The supply of food obviously acted as the controlling factor. The "calcareous" facies of the CORB of the Rača Unit has a considerably higher proportion of sand-dominated interbeds and also carbonates than the non-calcareous facies. This (especially the presence of carbonates) suggests a relative proximity of food-rich environments and an easy transport of nutrition-rich substrate by turbidite currents into the basin directly, not only by periodical fall-out of dead plankton (which is probably responsible for the rhythmicity of poor colonization horizons in weakly bioturbated units).

Impaired Colonization and Infection of Tomato Roots by the Δfrp1 Mutant of Fusarium oxysporum Correlates with Reduced CWDE Gene Expression

The vascular wilt pathogen Fusarium oxysporum f. sp. lycopersici efficiently invades roots and colonizes vascular tissues of its host tomato. For these processes, the F-box protein Frp1 is required. The Fusarium oxysporum Deltafrp1 mutant was characterized in detail to uncover the cause of its colonization defect. Using growth assays, we could attribute poor root colonization to reduced assimilation of organic acids, amino acids (except proline), or polysaccharides, singly or in combination. External root colonization by the Deltafrp1 mutant is restored by the addition of 0.1% glucose or proline but infection still does not occur. This is due to the inability of the Deltafrp1 mutant to penetrate the roots, as demonstrated by the lack of expression of SIX1 in the Deltafrp1 strain, which is a gene exclusively expressed inside roots, and loss of cell wall-degrading enzyme (CWDE) gene expression. Many of the metabolic defects of the Deltafrp1 strain can be attributed to reduced expression of the ICL1 (isocitrate lyase) gene. Strikingly, an Deltaicl1 mutant is still fully pathogenic and capable of external root colonization. We conclude that the inability of the Deltafrp1 strain to colonize and invade roots is not primarily due to metabolic defects but can be attributed to reduced expression of several CWDE genes.

The Use of Flagella and Motility for Plant Colonization and Fitness by Different Strains of the Foodborne Pathogen Listeria monocytogenes

The role of flagella and motility in the attachment of the foodborne pathogen Listeria monocytogenes to various surfaces is mixed with some systems requiring flagella for an interaction and others needing only motility for cells to get to the surface. In nature this bacterium is a saprophyte and contaminated produce is an avenue for infection. Previous studies have documented the ability of this organism to attach to and colonize plant tissue. Motility mutants were generated in three wild type strains of L. monocytogenes by deleting either flaA, the gene encoding flagellin, or motAB, genes encoding part of the flagellar motor, and tested for both the ability to colonize sprouts and for the fitness of that colonization. The motAB mutants were not affected in the colonization of alfalfa, radish, and broccoli sprouts; however, some of the flaA mutants showed reduced colonization ability. The best colonizing wild type strain was reduced in colonization on all three sprout types as a result of a flaA deletion. A mutant in another background was only affected on alfalfa. The third, a poor alfalfa colonizer was not affected in colonization ability by any of the deletions. Fitness of colonization was measured in experiments of competition between mixtures of mutant and parent strains on sprouts. Here the flaA and motAB mutants of the three strain backgrounds were impaired in fitness of colonization of alfalfa and radish sprouts, and one strain background showed reduced fitness of both mutant types on broccoli sprouts. Together these data indicate a role for flagella for some strains to physically colonize some plants, while the fitness of that colonization is positively affected by motility in almost all cases.

EFFECTS OF STAND AGE ON THE DEMOGRAPHY OF A TEMPERATE FOREST HERB IN POST‐AGRICULTURAL FORESTS

Changes in land use have been shown to have profound effects on forest plant community structure and diversity. Dispersal limitation has been invoked as a major factor hampering colonization of forest plant species, while seed-sowing experiments and performance observations have provided some evidence for recruitment limitation determining forest plant distribution in post-agricultural forests. However, most of these studies were relatively short-term, and very few studies have investigated long-term growth rates of populations occurring in recent and ancient forests. In this study, matrix models using demographic data collected for four consecutive years were used to study the effect of forest age on population dynamics of the temperate forest herb Primula elatior. A life table response experiment (LTRE) and elasticity analysis were used to analyze the effect of forest age on population growth rate (lambda) and to decompose the effect of forest age on lambda into contributions from each matrix element. Population growth increased logarithmically with increasing forest age. Bootstrap analyses showed that populations located in very recent forests (< 50-years-old) had growth rates that were significantly < 1, whereas populations located in forests > 150-years-old had growth rates that were significantly > 1. Summed elasticities for individual growth significantly decreased with increasing forest age, whereas summed elasticities for survival and fertility significantly increased with increasing forest age. The LTRE analysis showed that the increase in lambda with increasing forest age was mainly due to increased seedling and juvenile growth and increased juvenile and adult survival. Our results indicate that past agricultural land use has long-lasting effects on the demography of forest herbs and may provide an additional mechanistic explanation for the poor colonization capacity of many forest herbs in post-agricultural forests.

How Good Is the Quality of Colonoscopy Preparation Under Monitored Anesthesia Care (Mac)?

Purpose: MAC is used in our hospital endoscopy unit for colonoscopy in high risk patients (pts) only. However, routine instructions about overnight fasting in pts undergoing colonoscopy under MAC by the anesthesiologists limits the use of AM dose of split dose regimen, which may interfere with the quality of colon preparation (prep). The aim of our study was to compare the quality of colon prep in pts undergoing colonoscopy under MAC & conscious sedation (CS) at our hospital endoscopy unit by grading the endoscopic photographs. Methods: Patients: Between 01/07 and 04/08, 163 pts underwent colonoscopy under MAC (study group); 57 pts used polyethylene glycol (PEG) based solution, 66 pts used Phosphosoda + Dulcolax (P), and 40 used other solutions. Two hundred pts undergoing colonoscopies under CS using PEG (N = 100) & P (N = 100) served as controls. Assessment: Grading of Cleansing For Each Colonic Segment was done by a single observer looking at the colonoscopy photos- Poor prep = stool obscured the mucosa; Fair prep = 50–100% of mucosa visualized along with few specks of stool; Excellent prep = 100% of the mucosa visualized without any stool. The Colon Cleansing Score for each colonoscopy exam was based on the overall quality of prep in different segments of the colon. Score 3: Excellent prep in all the segments of colon; Score 2: Fair prep in at least 1 segment; Score 1: Poor prep in at least 1 segment. Results: A. Poor Prep Rate: Higher in pts having colonoscopy under MAC as compared to those undergoing in CS (26% vs. 13.5%, P < 0.05). B. Colon Cleansing Score: Worse in pts having procedure under MAC compared to those undergoing in CS (2.15 ± 0.07 vs. 2.38 ± 0.05, P < 0.05) C. Effect of Prep Solution on Colon Prep Rate: Worse with PEG solution in the MAC group compraed to CS group (36% vs. 16%, P < 0.05), but no difference with Phosphosoda + Dulcolax (18% vs 11%, P= NS). ASA score: In the MAC group, the mean ASA score was 2.42 ± 0.06 and the CS group was 2.01 ± 0.03. (P < 0.05) Conclusion: Poor colon preparation is frequent in patients undergoing colonoscopy under MAC and especially worse with the use of PEG solution. Since these patients are sicker (higher ASA class), a split dose may benefit them (these under current investigation).Figure

A Retrospective Chart Review Investigating the Use of Colonoscopy in the Elderly

Purpose: Currently, there are no guidelines regarding colonoscopy in the elderly population, excluding cancer screening. There is conflicting data regarding the use of colonoscopy in patients over the age of 80. There exists a significant population in the elderly undergoing colonoscopy for screening, fecal occult blood positive results, hematochezia, and change in bowel habits. Methods: A retrospective chart review from 11/01/04 to 10/13/06 was performed on all patients who underwent a colonoscopy at a community hospital. Patient age, sex, indication for colonoscopy, adverse events during the procedure, findings during colonoscopy, and results of biopsy or polypectomy, if completed, were all documented. A colonoscopy performed for a screening exam, fecal occult blood positive, hematochezia, and change in bowel habits were included. Results: A total of 173 colonoscopic examinations took place that met the strict inclusion/exclusion criteria of the study. Four adverse events occurred in our study population. Two colonic perforations and two events of aspiration occurred. Additionally, seven patients had incomplete exams due to a poor colon preparation. Of the 173 examinations, only 1 examination revealed a malignant process. This malignancy was found in a patient with change in bowel movements. No malignant lesions were found in the hematochezia and screening population of the study. Conclusion: Colonoscopy in patients over the age of 80 demonstrated minimal diagnostic yield. Colonoscopy itself does carry risk of adverse events that must be considered, especially when diagnostic yield is extremely minimal. Further research is necessary to establish guidelinesTable: Colonoscopy in the Elderly.

Predictors of Poor Bowel Preparation in Colonoscopy

Purpose: A poorly prepared colon can lead to missed lesions and repeated procedures that increase cost and complication risk. The aim of the study was to identify predictive factors of poor colon prep, including obesity, which increases risk of neoplasia. Methods: Retrospective review of 1815 reports of inpatient (IP) and outpatient (OP) colonoscopies performed from June to October 2007 at a tertiary referral center. Prior colectomy, repeat colonoscopy, incomplete reports were excluded and 1588 reports analyzed. The endoscopist's inability to adequately evaluate the entire colonic mucosa and request for earlier than expected repeat colonoscopy (ACG, ASGE guidelines) were used to determine a poor or inadequate prep (PIP). Results: Good to excellent prep quality was reported in 400 (25.2%) patients and PIP in 627 (39.5%) patients. Patients with PIP were older (59.57 ± 13.5 yrs) and had higher weight (86.19 ± 23.9 kg) and BMI (29.74 ± 7.84 kg/m2) (P < .01). In univariate analysis, male gender, inpatient status (IP), Polyethylene glycol based lavage (PEG), smoking, lack of regular alcohol consumption, diabetes mellitus (DM), hypertension, coronary artery disease (CAD) increased BMI, depression, mental retardation (MR) and use of anti-depressant medications or narcotics were predictive of PIP. However, in multivariate logistic regression analysis, only male gender (OR = 0.75, P= 0.02), IP status (OR = 1.92, P= 0.002), smoking (OR = 1.62, P= 0.003), lack of regular alcohol consumption (OR = 0.68, P= 0.0003), DM (OR = 1.64, P= 0.0006), MR (OR = 3.54, P= 0.0004), narcotic use (OR = 3.04, P < 0.0001), and PEG (OR = 0.53, P= 0.0004) were predictors of poor bowel preparation. Modeling for composite outcome using univariate analysis: older age, male gender, IP status, smoking, lack of regular alcohol consumption, DM, hypertension, CAD, increased BMI, depression, obstructive sleep apnea, MR and consumption of anti-depressant medications or narcotics were predictive of PIP. However, in multivariate logistic regression analysis, only older age (OR = 1.009, P= 0.01), male gender (OR = 0.71, P= 0.002), IP status (OR = 1.55, P= 0.008), smoking (OR = 1.35, P= 0.01), lack of regular alcohol consumption (OR = 0.7, P= 0.01), increased BMI (OR = 1.02, P= 0.004), MR (OR = 2.17, P= 0.03), use of antidepressant medication (OR = 1.69, P= 0.001), and narcotic use (OR = 2.1, P= 0.001) were predictors of PIP. Conclusion: Poorly prepped colons reduce diagnostic yield. Aborted and repeat procedures greatly increase the cost of colonoscopy. Prior identification and aggressive bowel cleansing of patients with predictive factors of PIP can lead to improved diagnostic yield and cost savings. This needs to be verified in a prospective study.

Comparison of the stress response of Listeria monocytogenes strains with sprout colonization.

Twenty-nine strains of the foodborne pathogen Listeria monocytogenes were tested for their ability to colonize alfalfa, radish, and broccoli sprouts and their capacity to withstand acid and oxidative stress, two stresses common to the sprouting environment. Wide variation in the ability of different strains to colonize alfalfa sprouts were confirmed, but the variations among radish and broccoli sprouts were not as large. With a few exceptions, strains that were poor colonizers of alfalfa tended to be among the poorer colonizers of radish and broccoli and vice versa. The strains also were variable in their resistance to both acid and oxidative stress. Statistical analysis revealed no correlation between acid stress and sprout colonization, but there was a positive correlation between resistance to oxidative stress and colonization of all three sprout types. Although the response to oxidative stress is important for L. monocytogenes virulence, it also may be important for life outside of a host.

Protein kinase C (PKC), p38 kinase, and mitogen activated protein kinases (MAPK) signaling enhance 1 alpha, 25 dihydroxyvitamin D3 (1,25 D)‐regulated 25‐hydroxyvitamin D‐24‐hydroxylase (CYP24) gene expression in Caco‐2 cells.

High vitamin D status protects against colon cancer but high CYP24 activity degrades 1,25D, reduces its genomic action, and is associated with poor colon cancer prognosis. Many kinase pathways are activated in cancer and these may affect 1,25D‐mediated CYP24 gene expression. Phorbol ester (PMA) treatment activated multiple signaling pathways and enhanced 1,25D‐induced CYP24 gene transcription (mRNA, 180%; reporter gene, 150%). Inhibition of PKC, MEK or p38 kinase each reduced PMA‐effects on 1,25D‐induced CYP24 mRNA and reporter genes by 20–40%. Reporter gene studies identified the region between −298 to +74 bp in the CYP24 promoter (containing two 1,25D response elements (VDRE)) as critical for the PMA effect. PMA enhanced 1,25D transcription through the VDRE is related to phosphorylation of the co‐activator mediator 1. Mutation of a VSE site (a putative site for PKC) and inhibiting Sp1 binding (a p38 kinase target) to DNA each reduced the PMA effect by an additional 30%. However, mutation of an EBS site (an ERK5 target site) had no impact. These data suggest that activation of kinase pathways associated with cancer (PKC, MAPK, p38 kinase) independently regulate 1,25D induced CYP24 gene expression through multiple regulatory motifs. This may reduce 1,25D‐induced anti‐cancer actions.

Computed tomographic air-contrast enema imaging for presurgical examination of colon tumors: assessment with colon phantoms and in patients

We investigated the mechanism of colon wall deformities in phantoms and assessed the relation between pathological T staging and wall deformity in patients using computed tomography (CT) enema imaging. We performed multidetector-row CT in mass-containing phantoms with no structural deformities and in 36 patients with colon tumors. In the phantoms, we compared images on double-contrast barium (DCB) and CT enema studies, and we compared wall deformities on CT enema studies and the actual phantom structure. In patients, we compared wall deformities on CT enema studies and T staging. Images from CT enema and DCB studies were identical in the phantom, and all profile images showed geometrical basal indentations. In patients, the grade of deformity increased with invasion depth; and the diagnostic accuracy of T staging was 82.5%. Geometrical basal indentation and poor colon expansion were the primary reasons for overestimating T staging on CT enema imaging. Although CT enema imaging allows reasonable diagnostic accuracy of T staging, wall deformity is thought to be consistent with tumor infiltration and other factors. We recommend evaluating T staging using not only CT enema imaging but also other techniques, such as virtual endoscopy, axial imaging, and multiplanar reformation imaging.

Proteomic Analyses of a Robust versus a Poor Chicken Gastrointestinal Colonizing Isolate ofCampylobacter jejuni

Campylobacter spp. are a significant contributor to the bacterial etiology of acute gastroenteritis in humans. Epidemiological evidence implicates poultry as a major source of the organism for human illness. However, the factors involved in colonization of poultry with Campylobacter spp. remain unclear. Determining colonization-associated factors at the proteome level should facilitate our understanding of Campylobacter spp. contamination of poultry. Therefore, proteomic analyses were utilized to identify expression differences between two Campylobacter jejuni isolates, a robust colonizer A74/C and a poor colonizing strain of the chicken gastrointestinal system designated NCTC 11168-PMSRU. Proteomic analyses by two-dimensional gel electrophoresis revealed the specific expression of an outer membrane-fibronectin binding protein, serine protease, and a putative aminopeptidase in the soluble portion of the robust colonizer A74C. Several proteins including a cysteine synthase and aconitate hydratase were detected specifically in the poor colonizer C. jejuni NCTC 11168-PMSRU isolate. Variation in the amino acid sequences resulting in different isoelectric points and relative mobility of the flagellin and C. jejuni major outer membrane (MOMP) protein were also detected between the two isolates. Western blotting of the bacterial proteins revealed the presence of two flagellin proteins in the poor colonizer versus one in the robust colonizing isolate, but no differences in MOMP. The results demonstrated that proteomics is useful for characterizing phenotypic variation among Campylobacter spp. isolates. Interestingly, different gene products potentially involved in robust colonization of chickens by Campylobacter spp. appear to conform to recently identified expression patterns in Biofilm or agar-adapted isolates.