Sun‐induced fluorescence – a new probe of photosynthesis: First maps from the imaging spectrometer HyPlant

Variations in photosynthesis still cause substantial uncertainties in predicting photosynthetic CO₂ uptake rates and monitoring plant stress. Changes in actual photosynthesis that are not related to greenness of vegetation are difficult to measure by reflectance based optical remote sensing techniques. Several activities are underway to evaluate the sun‐induced fluorescence signal on the ground and on a coarse spatial scale using space‐borne imaging spectrometers. Intermediate‐scale observations using airborne‐based imaging spectroscopy, which are critical to bridge the existing gap between small‐scale field studies and global observations, are still insufficient. Here we present the first validated maps of sun‐induced fluorescence in that critical, intermediate spatial resolution, employing the novel airborne imaging spectrometer HyPlant. HyPlant has an unprecedented spectral resolution, which allows for the first time quantifying sun‐induced fluorescence fluxes in physical units according to the Fraunhofer Line Depth Principle that exploits solar and atmospheric absorption bands. Maps of sun‐induced fluorescence show a large spatial variability between different vegetation types, which complement classical remote sensing approaches. Different crop types largely differ in emitting fluorescence that additionally changes within the seasonal cycle and thus may be related to the seasonal activation and deactivation of the photosynthetic machinery. We argue that sun‐induced fluorescence emission is related to two processes: (i) the total absorbed radiation by photosynthetically active chlorophyll; and (ii) the functional status of actual photosynthesis and vegetation stress.     

Increased apoptotic sensitivity of glioblastoma enables therapeutic targeting by BH3-mimetics

Glioblastoma (GBM) is the most prevalent malignant primary brain tumour in adults. GBM typically has a poor prognosis, mainly due to a lack of effective treatment options leading to tumour persistence or recurrence. We investigated the therapeutic potential of targeting anti-apoptotic BCL-2 proteins in GBM. Levels of anti-apoptotic BCL-xL and MCL-1 were consistently increased in GBM compared with non-malignant cells and tissue. Moreover, we found that relative to their differentiated counterparts, patient-derived GBM stem-like cells also displayed higher expression of anti-apoptotic BCL-2 family members. High anti-apoptotic BCL-xL and MCL-1 expression correlated with heightened susceptibility of GBM to BCL-2 family protein-targeting BH3-mimetics. This is indicative of increased apoptotic priming. Indeed, GBM displayed an obligate requirement for MCL-1 expression in both tumour development and maintenance. Investigating this apoptotic sensitivity, we found that sequential inhibition of BCL-xL and MCL-1 led to robust anti-tumour responses in vivo, in the absence of overt toxicity. These data demonstrate that BCL-xL and MCL-1 pro-survival function is a fundamental prerequisite for GBM survival that can be therapeutically exploited by BH3-mimetics.Subject terms: Cancer genetics, Cell biology     

Development and validation of the K‐VSCOR for scoring Koebner's phenomenon in vitiligo/non‐segmental vitiligo

The relation of vitiligo/non‐segmental vitiligo (NSV) to Koebner's phenomenon is variably appreciated. Our objective was to develop and validate a simple clinical score for Koebner's phenomenon (KP) in patients with vitiligo/NSV. The study population was composed of 351 individuals in the development sample and 285 patients in the validation sample. Seven variables were independently associated with the presence of KP: disease duration of more than 3 yr, forehead + scalp areas, eyelids, wrists, genital + belt areas, knees and tibial crests. The score computed by the weighted sum of the rounded coefficients of these seven variables ranged from 0 to 56 (mean 38.39 ± 22.93). The probability of having KP was computed as follows: exp (?2.37 + 0.1*score)/exp [1 + (?2.37 + 0.1*score)]. When applying the score to each patient in the validation and the development sample, the score maintained adequate discrimination and calibration (AUC‐ROC = 0.78), arguing that KP can be adequately predicted using our score. Further studies should evaluate KP assessed by the K‐VSCOR in clinical practice with the aim to determine its association with clinical profile, course and treatment response of vitiligo.     

Autophagy Inhibition Mediates Apoptosis Sensitization in Cancer Therapy by Relieving FOXO3a Turnover

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Biosorption of zinc by fungal mycelial wastes

Summary Waste mycelia from several industrial fermentation plants (Aspergillus niger, Penicillium chrysogenum, Claviceps paspali) were used as a biosorbent for zinc ions from aqueous environments, both batchwise as well as in a column mode. With all mycelia testes, biosorption per biomass dry weight was a function of pH (increasing with increasing pH between 1.0 and 9.0), biomass concentration (decreasing at high biomass concentrations) and the zinc concentration. Under optimized conditions, A. niger and C. paspali were superior to P. chrysogenum. Treatment of A. niger biomass with NaOH further increased its biosorbent capacity. Desorption of biosorbed zinc was achieved by elution with 0.1 m HCl, best results being obtained with NaOH-treated A. niger. Such treatment did not affect the capacity for biosorption in repeated experiments. NaOH-treated A. niger mycelia were also successfully used in removal of zinc from polluted waters in Austria, thereby showing that the simultaneous presence of other naturally occurring ions does not affect biosorption. Offprint requests to: C. P. Kubicek     

A HPLC-fluorescence detection method for determination of phosphatidic acid phosphohydrolase activity: application in human myocardium

Phosphatidic acid phosphohydrolase (PAP) catalyzes the dephosphorylation of phosphatidic acid (PA) to diacylglycerol, the second messenger responsible for activation of protein kinase C. Despite the crucial role of PAP lipid signaling, there are no data on PAP signaling function in the human heart. Here we present a nonradioactive assay for the investigation of PAP activity in human myocardium using a fluorescent derivative of PA, 2-(4,4-difluoro-5,7-dimethyl-4-bora-3a,4a-diaza-s-indacene-3-pentanoyl)-1-hexadecanoyl-sn-glycero-3-phosphate (BODIPY-PA), as substrate in an in vitro PAP-catalyzed reaction. Unreacted BODIPY-PA was resolved from the PAP products by a binary gradient HPLC system and BODIPY-diacylglycerol was detected by fluorimetry. The reaction proceeded at a linear rate for up to 60 min and increased linearly with increasing amounts of cardiac protein in a range of 0.25 to 8.0 μg. This assay proved to be sensitive for accurate quantitation of total PAP activity, PAP-1 activity, and PAP-2 activity in human atrial tissue and right ventricular endomyocardial biopsies. Total PAP activity was approximately fourfold higher in ventricular myocardium than in atrial tissue. There was negligible PAP-1 activity in atrial myocardium compared with ventricular myocardium, indicating regional differences in activities and distribution pattern of PAP-1 and PAP-2 in the human heart.