Volatile organic compounds as non-invasive markers for plant phenotyping.

Plants emit a great variety of volatile organic compounds (VOCs) that can actively participate in plant growth and protection against biotic and abiotic stresses. VOC emissions are strongly dependent on environmental conditions; the greatest ambiguity is whether or not the predicted change in climate will influence and modify plant-pest interactions that are mediated by VOCs. The constitutive and induced emission patterns between plant genotypes, species, and taxa are highly variable and can be used as pheno(chemo)typic markers to distinguish between different origins and provenances. In recent years significant progress has been made in molecular and genetic plant breeding. However, there is actually a lack of knowledge in functionally linking genotypes and phenotypes, particularly in analyses of plant-environment interactions. Plant phenotyping, the assessment of complex plant traits such as growth, development, tolerance, resistance, etc., has become a major bottleneck, and quantitative information on genotype-environment relationships is the key to addressing major future challenges. With increasing demand to support and accelerate progress in breeding for novel traits, the plant research community faces the need to measure accurately increasingly large numbers of plants and plant traits. In this review article, we focus on the promising outlook of VOC phenotyping as a fast and non-invasive measure of phenotypic dynamics. The basic principle is to define plant phenotypes according to their disease resistance and stress tolerance, which in turn will help in improving the performance and yield of economically relevant plants.

Pollen-derived adenosine is a necessary cofactor for ragweed allergy.

BACKGROUND: Ragweed (Ambrosia artemisiifolia) is a strong elicitor of allergic airway inflammation with worldwide increasing prevalence. Various components of ragweed pollen are thought to play a role in the development of allergic responses. The aim of this study was to identify critical factors for allergenicity of ragweed pollen in a physiological model of allergic airway inflammation. METHODS: Aqueous ragweed pollen extract, the low molecular weight fraction or the major allergen Amb a 1 was instilled intranasally on 1-11 consecutive days, and allergic airway inflammation was evaluated by bronchoalveolar lavage, lung histology, serology, gene expression in lung tissue, and measurement of lung function. Pollen-derived adenosine was removed from the extract enzymatically to analyze its role in ragweed-induced allergy. Migration of human neutrophils and eosinophils toward supernatants of ragweed-stimulated bronchial epithelial cells was analyzed. RESULTS: Instillation of ragweed pollen extract, but not of the major allergen or the low molecular weight fraction, induced specific IgG1 , pulmonary infiltration with inflammatory cells, a Th2-associated cytokine signature in pulmonary tissue, and impaired lung function. Adenosine aggravated ragweed-induced allergic lung inflammation. In vitro, human neutrophils and eosinophils migrated toward supernatants of bronchial epithelial cells stimulated with ragweed extract only if adenosine was present. CONCLUSIONS: Pollen-derived adenosine is a critical factor in ragweed-pollen-induced allergic airway inflammation. Future studies aim at therapeutic strategies to control these allergen-independent pathways.

Kinetic analyses of plant water relocation using deuterium as tracer - reduced water flux of Arabidopsis pip2 aquaporin knockout mutants.

Due to reduced evaporation and diffusion of water molecules containing heavier isotopes, leaf water possesses an elevated (18)O or (2)H steady-state content. This enrichment has been exploited in plant physiology and ecology to assess transpiration and leaf water relations. In contrast to these studies, in this work the (2)H content of the medium of hydroponically grown Arabidopsis thaliana was artificially raised, and the kinetics of (2)H increase in the aerial parts recorded during a short phase of 6-8 h, until a new equilibrium at a higher level was reached. A basic version of the enrichment models was modified to establish an equation that could be fitted to measured leaf (2)H content during uptake kinetics. The fitting parameters allowed estimation of the relative water flux q(leaf) into the Arabidopsis rosette. This approach is quasi-non-invasive, since plants are not manipulated during the uptake process, and therefore, offers a new tool for integrated analysis of plant water relations. The deuterium tracer method was employed to assess water relocation in Arabidopsis pip2;1 and pip2;2 aquaporin knockout plants. In both cases, q(leaf) was significantly reduced by about 20%. The organ and cellular expression patterns of both genes imply that changes in root hydraulic conductivity, as previously demonstrated for pip2;2 mutants, and leaf water uptake and distribution contributed in an integrated fashion to this reduced flux in intact plants.

Analysis of competition effects in mono- and mixed cultures of juvenile beech and spruce by means of the plant growth simulation model PLATHO.

Inter- and intra-specific competition between plants for external resources is a critical process for plant growth in natural and managed ecosystems. We present a new approach to simulate competition for the resources light, water, and nitrogen between individual plants within a canopy. This approach was incorporated in a process-oriented plant growth simulation model. The concept of modelling competition is based on competition coefficients calculated from the overlap of occupied crown and soil volumes of each plant individual with the occupied volumes of its four nearest neighbours. The model was parameterised with data from a two-year phytotron experiment with juvenile beech and spruce trees growing in mono- and mixed cultures. For testing the model, an independent data set from this experiment and data from a second phytotron experiment with mixed cultures were used. The model was applied to analyse the consequences of start conditions and plant density on plant-plant competition. In both experiments, spruce dominated beech in mixed cultures. Based on model simulations, we postulate a large influence of start conditions and stand density on the outcome of the competition between the species. When both species have similar heights at the time of canopy closure, the model suggests a greater morphological plasticity of beech compared with spruce to be the crucial mechanism for competitiveness in mixed canopies. Similar to the experiment, in the model greater plasticity was a disadvantage for beech leading to it being outcompeted by the more persistent spruce.

Comparison of ozone uptake and sensitivity between a phytotron study with young beech and a field experiment with adult beech (Fagus sylvatica).

Chamber experiments on juvenile trees have resulted in severe injury and accelerated loss of leaves along with reduced biomass production under chronically enhanced O3 levels. In contrast, the few studies conducted on adult forest trees in the field have reported low O3 sensitivity. In the present study, young beech in phytotrons was more sensitive to O3 than adult beech in the field, although employed O3 regimes were similar. The hypotheses tested were that: (1) differences in O3 uptake were caused by the ontogenetically higher stomatal conductance of young compared to adult trees, (2) the experimental settings in the phytotrons enhanced O3 uptake compared to field conditions, and (3) a low detoxification capacity contributes to the higher O3 sensitivity of the young trees. The higher O3 sensitivity of juvenile beech in the phytotrons is demonstrated to relate to both the experimental conditions and the physiological responsiveness inherent to tree age.

Short term effects of ozone on the plant-rhizosphere-bulk soil system of young beech trees.

Plant growth largely depends on microbial community structure and function in the rhizosphere. In turn, microbial communities in the rhizosphere rely on carbohydrates provided by the host plant. This paper presents the first study on ozone effects in the plant-rhizosphere-bulk soil system of 4-year-old beech trees using outdoor lysimeters as a research platform. The lysimeters were filled with homogenized soil from the corresponding horizons of a forest site, thus minimizing field heterogeneity. Four lysimeters were treated with ambient ozone (1 x O3) and four with double ambient ozone concentrations (2 x O3; restricted to 150 ppb). In contrast to senescence, which was almost unaffected by ozone treatment, both the photochemical quantum yield of photosystem II (PSII) and leaf gas exchange were reduced (11 - 45 %) under the elevated O3 regime. However, due to large variation between the plants, no statistically significant O3 effect was found. Even though the amount of primary metabolites, such as sugar and starch, was not influenced by elevated O3 concentrations, the reduced photosynthetic performance was reflected in leaf biochemistry in the form of a reduction in soluble phenolic metabolites. The rhizosphere microbial community also responded to the O3 treatment. Both community structure and function were affected, with a tendency towards a lower diversity and a significant reduction in the potential nutrient turnover. In contrast, litter degradation was unaffected by the fumigation, indicating that in situ microbial functionality of the bulk soil did not change.

The nursing human resource budget: design for success.

As vital as the nursing human resource budget is to the successful achievement of institutional goals, it is very important to present a well-developed budget. Using current automated spreadsheet technology, the nursing human resource budget can be laid out in a format that is easy to understand and easy to present. Using the methods discussed in this article, the nurse executive will be able to perform infinite iterations of the proposed budget with a few simple key strokes, thus allowing for things like zero-based budgeting or addition of programs during the budgeting process or at a later date. Implications for nurse executives are discussed.

Electrophysiologic abnormalities in patients with hypertrophic cardiomyopathy. A consecutive analysis in 155 patients.

Electrophysiologic studies (EPS) were performed in 155 patients with hypertrophic cardiomyopathy (HCM). Indications for EPS were cardiac arrest in 22 patients, syncope in 55 patients, presyncope in 37 patients, asymptomatic ventricular tachycardia (VT) in 24 patients, palpitations in 10 patients, and a strong family history of sudden cardiac death in seven patients. Thirty-five (23%) patients had significant resting left ventricular outflow tract obstruction. Electrophysiologic abnormalities were present in 126 (81%) patients. A high prevalence of abnormal sinus-node function (66%) and His-Purkinje (HV) conduction (30%) was noted. The most commonly induced supraventricular arrhythmias were atrial reentrant tachycardia and atrial fibrillation (10% and 11% of patients, respectively). Accessory atrioventricular pathways were present in seven (5%) patients. Programmed ventricular stimulation (PVS) induced nonsustained ventricular tachycardia in 22 (14%) patients and sustained ventricular arrhythmia in 66 (43%) patients. Sustained ventricular arrhythmia was polymorphic VT in 48 (73%) patients, monomorphic VT in 16 (24%) patients, and ventricular fibrillation in two (3%) patients. Induction was with two premature stimuli in 19 (29%) patients and three premature stimuli in 47 (71%) patients. Of 17 cardiac arrest survivors with sustained ventricular arrhythmia, 16 (94%) patients required three premature stimuli for arrhythmia induction. Sustained ventricular arrhythmia was induced at a right ventricular site in 51 (77%) patients and at a left ventricular site in 15 (23%) patients. Univariate analysis showed a significant (p less than 0.05) association between inducibility of sustained ventricular arrhythmia and VT on Holter in patients with a history of cardiac arrest or syncope but not in patients with presyncope or asymptomatic patients. Multivariate logistic regression analysis revealed that the following were significantly associated with inducibility of sustained ventricular arrhythmia: clinical presentation (cardiac arrest more than syncope more than presyncope more than asymptomatic patients, p = 0.0002; chronic or inducible atrial fibrillation, p = 0.002; and male gender, p = 0.04). In contrast, there was no clinical correlate of induced nonsustained VT.(ABSTRACT TRUNCATED AT 400 WORDS)

Auditory brainstem response in auditory assessment of acute severely burned children.

The burn population often requires ototoxic drugs in the treatment of infection. Previous investigations indicate that cochlear damage and auditory impairment may result from this medical therapy. In recent years, the auditory brainstem response (ABR) has assumed an important role in pediatric auditory assessment. We describe a test protocol for ABR assessment in the severely burned child. In a series of 69 acute severely burned children, 13% showed evidence of auditory deficit by the ABR. Based on our experiences, we recommend the inclusion of routine auditory evaluations, including ABR, in the diagnosis and rehabilitation of these children.

Auditory brainstem response in young burn-wound patients treated with ototoxic drugs.

Burn-wound patients often require potentially ototoxic doses of aminoglycoside drugs in the treatment of gram-negative sepsis. Cochlear hearing impairment may be an unfortunate consequence of this medical therapy. We evaluated auditory sensitivity with the auditory brainstem response (ABR) in a group of 32 children with acute, severe thermal burns ranging in age from 18 months to 17 years. The mean percent of total body surface area burns was 64%. None of the subjects had a known history of hearing deficits or aminoglycoside therapy, and all yielded a normal baseline ABR upon hospital admission. Eight of the subjects (22%) showed either an abnormal ABR, or no response, at 40 dB prior to hospital discharge. The medical treatment for this group of subjects (gentamicin, amikacin, vancomycin, amphotericin B) was compared to that of a second subgroup of 7 subjects without auditory deficit but with a statistically comparable percentage of burns. The mean dosage of vancomycin was higher for the auditory impairment group than for the unimpaired group. Prediction of ototoxicity in the acute burned patient is extremely difficult as there are numerous factors that may influence the risk of cochlear damage. We conclude, however, that the ABR can be applied in early detection of auditory deficit. Follow-up audiometric assessment is advisable since auditory deficits in this population may be delayed or progressive after discontinuance of drug therapy.

The quality of life after major thermal injury in children: an analysis of 12 survivors with greater than or equal to 80% total body, 70% third-degree burns.

Twenty-one children admitted between December 1981 and May 1985, with greater than 80% total body surface area burn (TBSAB), underwent total excision and grafting of all of their wounds within 72 hours of injury. Twelve survivors (with an average TBSAB of 89%, 82% third degree) were studied in detail describing the length of hospital stay (77 +/- 10 days), number of operative procedures (7.8 +/- 0.8), total blood loss (12 +/- 2 blood volumes), the number of patients who experienced septic episodes (three), the number of patients who required amputation (four), range of motion, degree of scarring, ability to perform daily activities, and psychological adjustment. Physical impairment, according to standard scales, was approximately 60%; however, 50% of the children old enough to be tested were completely independent in activities of daily living. One third of the children had excessive fear, regression, and neurotic and somatic complaints, but all of them showed remarkable energy in adapting to their disabilities. We conclude that the final outcome, for these patients, can only be assessed as they achieve late adolescence and young adulthood.