First Report of Fludioxonil-Resistant Isolates of Fusarium spp. Causing Potato Seed-Piece Decay.

Potato (Solanum tuberosum L.) diseases incited by Fusarium spp. include postharvest dry rot and seed-piece decay. Fusarium seed-piece decay is commonly controlled by preplant applications of chemical seed treatments. However, isolates of Fusarium spp. resistant to benzimidazole fungicides have been reported (2,4). In the spring of 2007, samples of cut seed tubers (cvs. Shepody and Russet Burbank) showing extensive symptoms of decay were received from three seedlots in Prince Edward Island (PE) and one seedlot in Saskatchewan (SK), Canada. All seed tubers had been treated with fludioxonil (Maxim Potato Seed Protectant [PSP], 0.5% fludioxonil) following cutting and then stored for 10 to 14 days prior to planting. Using standard isolation protocols (4), the 19 potato tuber pieces examined from PE and 2 from SK yielded 21 Fusarium isolates for further study. Five isolates (including both isolates from SK) were identified as Fusarium sambucinum Fuckel and the remaining 16 isolates were identified as F. coeruleum (Libert) Sacc. (3). To confirm identifications, isolates were compared with two known standards of each of F. sambucinum and F. coeruleum identified by K. Seifert (Agriculture and Agri-Food Canada, Ottawa, ON) by DNA sequencing of the partial ß-tubulin gene or the translation elongation factor 1-α ( http://fusarium.cbio.psu.edu ; [1]). These standard isolates were also used as fludioxonil-sensitive controls in amended agar assays for chemical sensitivity. Agar plugs (5 mm in diameter) taken from the margins of 7-day-old cultures of the Fusarium isolates were transferred to petri dishes containing ½-strength potato dextrose agar amended with 0, 0.1, 1.0, 10.0, or 100.0 mg/liter of fludioxonil. Fludioxonil (Maxim PSP, 0.5% a.i.) was prepared as a stock solution in sterile distilled water and added to the molten agar after autoclaving. Culture incubation and mycelial growth measurements were performed as described previously (4). Measurements from four replicate petri dishes per concentration of fludioxonil were taken. Calculated EC50 values (fludioxonil concentration inhibiting pathogen growth by 50%) were obtained. The trial was repeated three times. The two standard isolates of F. sambucinum were sensitive to fludioxonil, with mean EC50 values of 0.002 (±0.002 standard error [SE]) and 0.005 (±0.002 SE) mg/liter. The two standard isolates of F. coeruleum were also sensitive to fludioxonil, with mean EC50 values of 0.17 (±0.005 SE) and 0.19 (± 0.005 SE) mg/liter. All other tested isolates of F. sambucinum and F. coeruleum were resistant to fludioxonil and showed no growth inhibition even at 100 mg of fludioxonil per liter. To our knowledge, this is the first report of resistance to fludioxonil in isolates of Fusarium spp. causing potato seed-piece decay. Since the isolates of F. sambucinum were also resistant to thiophanate-methyl and thiabendazole (data not shown), multiclass (benzimidazole and pyrrole) resistance was also documented. References: (1) D. M. Geiser et al. Eur. J. Plant Pathol. 110:473, 2004. (2) L. M. Kawchuk et al. Am. Potato J. 71:185, 1994. (3) P. E. Nelson et al. Fusarium Species: An Illustrated Manual for Identification. Pennsylvania State University Press, 1983. (4) R. D. Peters et al. Plant Dis. 85:1030, 2001.

Validity of the computer science and applications (CSA) activity monitor in children.

PURPOSE: The purpose of this study was to evaluate the validity of the CSA activity monitor as a measure of children's physical activity using energy expenditure (EE) as a criterion measure. METHODS: Thirty subjects aged 10 to 14 performed three 5-min treadmill bouts at 3, 4, and 6 mph, respectively. While on the treadmill, subjects wore CSA (WAM 7164) activity monitors on the right and left hips. VO2 was monitored continuously by an automated system. EE was determined by multiplying the average VO2 by the caloric equivalent of the mean respiratory exchange ratio. RESULTS: Repeated measures ANOVA indicated that both CSA monitors were sensitive to changes in treadmill speed. Mean activity counts from each CSA unit were not significantly different and the intraclass reliability coefficient for the two CSA units across all speeds was 0.87. Activity counts from both CSA units were strongly correlated with EE (r = 0.86 and 0.87, P < 0.001). An EE prediction equation was developed from 20 randomly selected subjects and cross-validated on the remaining 10. The equation predicted mean EE within 0.01 kcal.min-1. The correlation between actual and predicted values was 0.93 (P < 0.01) and the SEE was 0.93 kcal.min-1. CONCLUSION: These data indicate that the CSA monitor is a valid and reliable tool for quantifying treadmill walking and running in children.

Restrictive atrial septal communication as a determinant of outcome of cardiac transplantation for hypoplastic left heart syndrome.

BACKGROUND: Infant cardiac transplantation for hypoplastic left heart syndrome (HLHS) can be performed with a high success rate, but it remains unclear whether variations in anatomy or degree of illness before transplantation can affect ultimate survival. METHODS AND RESULTS: We analyzed the initial echocardiograms and pretransplant courses of 21 infants whose families chose transplantation as a primary therapy option for factors influencing survival. Sixteen of 21 were transplanted (mean wait, 18 days; range, 3 to 97 days) with 15 current (6- to 36-month) survivors, leading to a survival rate from presentation of 71% (70% confidence limit [CL], 61% to 81%) and an operative survival of 94% (70% CL, 81% to 99%). Seven of 20 listed for transplant (35%) had a severely restrictive interatrial communication, defined as a color flow jet width of 3 mm or less across the interatrial septum. Three of these 7 infants died at 4 (2) and 7 (1) weeks from congestive heart failure and progressive hypoxemia before transplantation. One died 2 months after transplant with an autopsy demonstrating pulmonary venous hypertensive disease, leading to a significantly higher relative risk for death (relative risk = 7.4, P = .01) for those infants with a severely restrictive interatrial communication versus those infants without severe restriction. The size and function of the right ventricle, left atrium, aorta, and tricuspid valve, as well as the magnitude of support on presentation, were not related to ultimate survival. CONCLUSIONS: A severely restrictive interatrial communication is a frequent component of HLHS. When primary cardiac transplantation is the chosen therapy for HLHS, it is a significant negative risk factor for death primarily before transplantation.