First Report of Umbel Browning and Stem Necrosis Caused by Diaporthe angelicae on Carrot in France.

In 2011, carrot (Daucus carota L.) seed production occurred on 2,900 ha, which accounts for approximately 25% of the area devoted to the production of vegetable fine seeds. Since 2007, symptoms of umbel browning have been regularly observed in carrot production areas located in the central region. Initially, triangular necrotic lesions appeared on carrot umbels that later spread to the entire umbels and often progressed to the stems. Diseased umbels became dried prematurely, compromising seed development. The loss in seed production was estimated at approximately 8% of the harvested carrot umbels during the cropping seasons of spring and summer 2007 and 2008 in France. In collaboration with seed companies, diseased carrot stems were collected from seven fields of seed production (eight plants per field) and a fungus was isolated from the tissue. The cultures were grown on malt (2%) agar (1.5%) medium and incubated for 2 weeks at 22°C in darkness. Young fungal colonies were white and a brownish green pigmentation developed when the colonies became older. The same color was observed from the top and on the reverse of the colonies. To induce sporulation, isolates were grown on water agar (1.5%) medium in the presence of carrot stem fragments for 1 week at 22°C in darkness, followed by 1 week at 22°C in white light under a 16-h photoperiod. Pycnidia were produced on stem fragments and contained alpha and beta conidia typical of the genus Diaporthe (2). Alternatively, pycnidia were also obtained on malt agar medium after 2 weeks of culture at 25°C in white light under a 12-h photoperiod. The size of alpha and beta conidia was 6.3 ± 0.5 × 2.3 ± 0.4 µm and 23.3 ± 1.8 × 0.9 ± 0.2 µm, respectively (n = 170). In order to confirm the identification at the genus level and determine the species, DNA was extracted from the mycelium of three representative isolates and the ITS regions of the ribosomal DNA were amplified using universal primers (1). The sequences of the amplified products (GenBank Accession Nos. KF240772 to KF240774) were 100% identical with the ITS sequence of a Diaporthe angelicae isolate deposited in the NCBI database (CBS 111592 isolate, KC343027). To confirm pathogenicity, the three isolates of D. angelicae were inoculated on carrot umbels in the greenhouse. A total of nine plants were inoculated (three plants per isolate). Using a micropipette, 10 µl of a conidial suspension containing alpha and beta conidia (105 conidia mL-1) were deposited at the base of the primary umbel and two secondary umbels, which were wounded before inoculation using a scalpel blade. Seven inoculated plants developed triangular, necrotic lesions that were typical umbel browning. D. angelicae was re-isolated on malt agar medium from the inoculated diseased carrot umbels. To our knowledge, this is the first report of D. angelicae in carrot cultivated for seed production in France. The disease resembles the lesions described in the Netherlands in 1951 on carrot inflorescence caused by Phomopsis dauci (3). In future experiments, it would be crucial to precisely determine if D. angelicae could be transmitted to the seeds. References: (1) M. A. Innis et al. PCR Protocols: A Guide to Methods and Applications. Academic Press, San Diego, CA, 1990. (2) J. M. Santos and A. J. L. Philips. Fungal Divers. 34:111, 2009. (3) J. A. von Arx. Eur. J. Plant Pathol. 57:44, 1951.

Impact of the unfolded protein response on the pathogenicity of the necrotrophic fungus Alternaria brassicicola.

The unfolded protein response (UPR) is an important stress signalling pathway involved in the cellular development and environmental adaptation of fungi. We investigated the importance of the UPR pathway in the pathogenicity of the plant necrotrophic fungus Alternaria brassicicola, which causes black spot disease on a wide range of Brassicaceae. We identified the AbHacA gene encoding the major UPR transcription regulator in A. brassicicola. Deletion of AbHacA prevented induction of the UPR in response to endoplasmic reticulum stress. Loss of UPR in mutants resulted in a complete loss of virulence and was also associated with a cell wall defect and a reduced capacity for secretion. In addition, our results showed that the UPR was triggered by treatment of mycelia with camalexin, i.e. the major Arabidopsis thaliana phytoalexin, and that strains lacking functional AbHacA exhibited increased in vitro susceptibility to antimicrobial plant metabolites. We hypothesize that the UPR plays a major role in fungal virulence by altering cell protection against host metabolites and by reducing the ability of the fungus to assimilate nutrients required for growth in the host environment. This study suggests that targeting the UPR pathway would be an effective plant disease control strategy.

Evaluation of incidence, clinical significance, and prognostic value of circulating cardiac troponin I and T elevation in hemodynamically stable patients with suspected myocardial contusion after blunt chest trauma.

BACKGROUND: The frequency and prognostic influence of myocardial injury in patients with blunt chest trauma is controversial. We investigated the value of cardiac troponin I (cTn-I) and cardiac troponin T (cTn-T), highly specific markers of myocardial injury, to determine whether their measurement would improve the ability to detect myocardial contusion in stable patients with blunt chest trauma in comparison with conventional markers and whether they were associated with significantly worse late clinical outcome. METHODS AND RESULTS: Over an 18-month period, myocardial contusion was diagnosed in 26 of 94 patients (27.6%) with acute blunt chest trauma (motor vehicle crash; 81%), because of echocardiographic abnormalities (n = 12), electrocardiographic abnormalities (n = 29), or both. Patients with myocardial contusion had a significantly higher Injury Severity Score at the time of admission (p = 0.001) and a significantly longer hospital stay (p = 0.0008). All patients survived admission to hospital and were hemodynamically stable. None of the patients died or had severe in-hospital cardiac complications. The percentage of patients with elevated CK, (CK-MB/total CK) ratio, or CK-MB mass concentration was not significantly different between patients with or without myocardial contusion. However, there were significant differences between the two groups when we applied the commonly used threshold levels of CK-MB activity and myoglobin. The percentage of patients with elevated circulating cTn-I and cTn-T (> or = 0.1 microg/L) was significantly higher in patients with myocardial contusion (23% vs. 3%; p = 0.01 and 12% vs. 0%; p = 0.03, respectively). Complete changes in cTn-I and cTn-T correlated well (r = 0.91, p = 0.0001). Sensitivity, specificity, and negative and positive predictive values of cTn-I and cTn-T in predicting a myocardial contusion in blunt trauma patients were 23%, 97%, and 77%, 75%, and 12%, 100%, and 74%, 100%, respectively. Clinical follow-up was available in 83 patients (88%) (mean, 16 +/- 7.5 months). There were no deaths in either group directly attributed to cardiac complications. None of the patients had any long-term cardiac complications or myocardial failure related to blunt chest trauma. CONCLUSION: Although improved specificity of cTn-I and cTn-T compared with conventional markers, it should be emphasized that the main problem with cTn-I and cTn-T is low sensitivity as well as low predictive values in diagnosing myocardial contusion. cTn-I and cTn-T measurement is currently not an improved method in diagnosing blunt cardiac injury in hemodynamically stable patients. Moreover, there was no association of postmyocardial contusion cell injury and late outcome in these patients when cTn-I and cTn-T and other conventional markers were considered.

Induced defence responses limit Hartig net formation in ectomycorrhizal birch roots.

Roots of clonal birches (Betula pendula) were inoculated with the ectomycorrhizal fungi Paxillus involutus (isolates P0 and Mi) and Hebeloma cylindrosporum (strains D1 and D105). These fungi showed different rates of mycorrhiza formation in vitro. Mature mycorrhizas were obtained after only 2-4 d with H. cylindrosporum, whereas 6-8 d were necessary with P. involutus isolate P0, and P. involutus isolate Mi was not able to form mature mycorrhiza during the 10 d of the experiment. Temporal changes in PAL activity and the expression of genes encoding intracellular pathogenesis-related proteins were followed after inoculating birch roots with these fungi. Transient increase of PAL activity, and transient induction of expression of the wound-inducible Bet v1-SC1 gene, were observed in roots challenged with both H. cylindrosporum strains and the P. involutus isolate P0. These changes were found to coincide with hyphal penetration between root cells during Hartig net formation, and were never observed in roots inoculated with the poorly aggressive P. involutus isolate Mi. Examination of mycorrhizal root sections under u.v. light indicated the presence of phenolic compounds in the host cell walls at the vicinity of the Hartig net. These results strongly suggest that hyphal penetration between the root cells triggers a transient defence response which, in turn, could limit Hartig net formation to the outer layer of the root cortex.

Pulmonary gas exchange capacity is reduced during normovolaemic haemodilution in healthy human subjects.

PURPOSE: To test the hypothesis that a physiological compensatory mechanism maintains respiratory gas exchange during normovolaemic haemodilution. METHODS: Pulmonary gas exchange capacity was evaluated in seven healthy subjects by measuring the lung diffusion of carbon monoxide (DLCO). During the measurement, various breath-holding times, inspiratory volumes, and sitting or supine positions, were randomly selected in an attempt to alter pulmonary capillary perfusion. KCO was calculated as the percentage of theoretical values of the ratio of DLCO by alveolar volume and normalized by sex, age, and height. Normovolaemic haemodilution (NH) was performed by bleeding an average blood volume of 1 L with simultaneous Dextran 60 replacement to obtain an haematocrit below 35%. RESULTS: After NH, haemoblogin concentration [Hb] decreased from 14.94 +/- 0.96 to 12.5 +/- 0.98 g.dl-1 (P < 0.001). KCO decreased (P < 0.02) but remained closely correlated to [Hb] at every lung volume (P < 0.02). Breathholding time and body position had no effect. CONCLUSION: Moderate NH impairs pulmonary gas exchange capacity in awake, resting healthy subjects. There is no evidence of any compensatory mechanism since the KCO vs [Hb] relationship is unchanged.

[Role of acute normovolemic hemodilution in treating retinal venous occlusions]. / Place de l'hémodilution aiguë normovolémique dans le traitement des occlusions veineuses rétiniennes.

The supposed state of retinal venous occlusions by a thrombus has led to the use of diverse antithrombotic treatments (heparin, fibrinolytic agents). This theory being considered at the moment as controversial, haemorheological theories being more particularly favoured, other treatments are proposed in an attempt to better retinal microcirculation, and this by changing the blood viscosity parameters. The study reported here compared the effects on recovery of visual acuity of retinal venous occlusion patients of anticoagulant treatment alone, haemodilution alone, or both together. After initial ophthalmic assessment, twenty-five patients were randomly assigned to one of three groups: group I (n = 5; mean age 62 +/- 14 yr) received heparin for 21 days, followed by antivitamin K drugs for a further 30 days; group II (n = 10; mean age 54 +/- 16 yr) were acutely hemodiluted with 40,000 daltons molecular weight dextran, bringing the haematocrit to between 0.25 and 0.30; on day 2, the same anticoagulant treatment as in group I was associated; group III (n = 10; mean age 58 +/- 18 yr) were only hemodiluted. The hemodiluted state was maintained for 21 days. A biological assessment was carried out for the three groups on days 1, 2, 7, 14, 21 and 30 (haematocrit, fibrinogen level, platelet count, kaolin-cephalin time, heparin level). The evolution of visual acuity was assessed on days 7, 14, 21, 30, 60 and 90. Mean visual acuity was assessed on days 7, 14, 21, 30, 60 and 90. Mean visual acuity was virtually the same for the three groups on day 0.(ABSTRACT TRUNCATED AT 250 WORDS)