Variety‐specific Epidemiology of Cercospora beticola Sacc. and Consequences for Threshold‐based Timing of Fungicide Application in Sugar Beet

In Central Europe, fungicides to control leaf spot disease in sugar beet caused by Cercospora beticola are applied based on thresholds of disease incidence (DI, per cent of infected plants). As variety‐specific fungicide application was not analyzed to date, the epidemiology of C. beticola and its effect on white sugar yield (WSY) in varieties with different susceptibility were investigated at seven sites in Germany and Austria in 2004 and 2005. All varieties reached the summary thresholds 5 / 15 / 45% DI in all environments. Fitting a logistic growth curve to DI revealed significant differences among varieties. At high disease pressure, susceptible varieties reached a considerably higher disease severity (DS, per cent of infected leaf area) at harvest and a larger area under disease progress curve (AUDPC) than resistant varieties. Fitting a logistic growth curve to DS showed an increasing differentiation among varieties with time. The growth rate estimated based on the logistic growth curve was the only variable that performed equally well in differentiating varieties under low and high disease pressure. With increasing disease pressure, varieties differed considerably in WSY, but differences between susceptible and resistant varieties were significant only in some environments. The disease‐loss relation between AUDPC and relative WSY was variety‐specific. Resistant varieties had an approximately identical WSY with and without infection and compensated for negative infection effects even at higher AUDPC. Therefore, at high disease pressure, resistant varieties had a higher relative yield compared to susceptible ones. However, our results indicate that there is no need to develop variety‐specific thresholds, but resistant varieties reach the established thresholds later than susceptible ones. Consequently, the time of fungicide application can be delayed in resistant varieties. This will help to reduce the use of fungicides to the bare essentials as requested for the integrated crop protection management.     

Effect of elevated dissolved carbon dioxide concentrations on growth of Corynebacterium glutamicum on D-glucose and L-lactate

The effect of increased dissolved carbon dioxide concentrations on growth of Corynebacterium glutamicum was studied with continuous turbidostatic cultures. The carbon sources were either l-lactate or d-glucose. To increase the dissolved carbon dioxide concentration the carbon dioxide partial pressure of the inlet gas stream pCO2,IN was increased stepwise from 0.0003 bar (air) up to 0.79 bar, while the oxygen partial pressure of the inlet gas stream was kept constant at 0.21 bar. For each resulting carbon dioxide partial pressure pCO2 the maximum specific growth rate mu(max) was determined from the feed rate resulting from the turbidostatic control. On d-glucose and pCO2 up to 0.26 bar, mu(max) was mostly constant around 0.58 h(-1). Higher pCO2 led to a slight decrease of mu(max). On l-lactate mu(max) increased gradually with increasing carbon dioxide partial pressures from 0.37 h(-1) under aeration with air to a maximum value of 0.47 h(-1) at a pCO2 of 0.26 bar. At very high pCO2 (0.81 bar) mu(max) decreased down to 0.35 h(-1) independent of the carbon source.     

High cell density cultivation of recombinant yeasts and bacteria under non-pressurized and pressurized conditions in stirred tank bioreactors

This study demonstrates the applicability of pressurized stirred tank bioreactors for oxygen transfer enhancement in aerobic cultivation processes. The specific power input and the reactor pressure was employed as process variable. As model organism Escherichia coli, Arxula adeninivorans, Saccharomyces cerevisiae and Corynebacterium glutamicum were cultivated to high cell densities. By applying specific power inputs of approx. 48kWm(-3) the oxygen transfer rate of a E. coli culture in the non-pressurized stirred tank bioreactor was lifted up to values of 0.51moll(-1)h(-1). When a reactor pressure up to 10bar was applied, the oxygen transfer rate of a pressurized stirred tank bioreactor was lifted up to values of 0.89moll(-1)h(-1). The non-pressurized stirred tank bioreactor was able to support non-oxygen limited growth of cell densities of more than 40gl(-1) cell dry weight (CDW) of E. coli, whereas the pressurized stirred tank bioreactor was able to support non-oxygen limited growth of cell densities up to 225gl(-1) CDW of A. adeninivorans, 89gl(-1) CDW of S. cerevisiae, 226gl(-1) CDW of C. glutamicum and 110gl(-1) CDW of E. coli. Compared to literature data, some of these cell densities are the highest values ever achieved in high cell density cultivation of microorganisms in stirred tank bioreactors. By comparing the specific power inputs as well as the k(L)a values of both systems, it is demonstrated that only the pressure is a scaleable tool for oxygen transfer enhancement in industrial stirred tank bioreactors. Furthermore, it was shown that increased carbon dioxide partial pressures did not remarkably inhibit the growth of the investigated model organisms.     

Isolation and Molecular Characterization of Chitinase-Deficient Bacillus licheniformis Strains Capable of Deproteinization of Shrimp Shell Waste To Obtain Highly Viscous Chitin

Proteolytic but chitinase-deficient microbial cultures were isolated from shrimp shell waste and characterized. The most efficient isolate was found to be a mixed culture consisting of two Bacillus licheniformis strains, which were first determined microscopically and physiologically. Molecular characterization was carried out by sequencing the 16S rRNA gene of both strains. According to the residual protein and ash content, the chitin obtained by fermentation of such a mixed culture was found to be comparable to a commercially available, chemically processed product. However, the strikingly high viscosity (80 versus 10 mPa of the commercially available sample) indicates its superior quality. The two strains differed in colony morphology and in their secretion capabilities for degradative extracellular enzymes. Sequencing of the loci encoding amylase, cellulase, chitinases, and proteases, as well as the degS/degU operon, which is instrumental in the regulation of degradative enzymes, and the pga operon, which is responsible for polyglutamic acid production, revealed no differences. However, a frameshift mutation in chiA, encoding a chitinase, was validated for both strains, providing an explanation for the ascertained absence of chitinolytic activities and the concomitant possibility of producing highly viscous chitin in a fermentational deproteinization process.     

Serum Level of CC-Chemokine Ligand 18 Is Increased in Patients with Non-Small-Cell Lung Cancer and Correlates with Survival Time in Adenocarcinomas

CC-chemokine ligand 18 (CCL18) is mainly expressed by alternatively activated macrophages and DCs and plays an important role in lung fibrosis, arthritis and other diseases. Here CCL18 was measured in sera of 31 healthy volunteers and 170 patients with lung cancer and correlated these data with histology, tumor stage and clinical parameters. Mean CCL18 serum level of the patients with non-small-cell lung cancer was 150(857) ng/ml vs. 32(61) ng/ml in the healthy control group. Patient groups differ significantly according their histology (adenocarcinoma 143(528) ng/ml vs squamous cell carcinoma 187(857) ng/ml, p<0.02). In addition, we found a significant difference between patients with lower versus higher T-stage (p<0.003). Receiver operating characteristic (ROC) analyses revealed a cutoff point of 83 ng/ml (area under the curve (AUC): 0.968; p<0.0001) to discriminate between healthy controls and non-small-cell lung cancer patients. ROC analyses to discriminate between patients, who died because of cancer related death and those who died for other reasons did not lead to a valid AUC. To stratify the tumor patients, a criterion value plot was performed leading to a point of equal sensitivity and specificity (54%) of 162 ng/ml. Patients with a CCL18 serum level higher than 160 ng/ml had a mean survival time of 623 days. In contrast, those in patients with a baseline level between 83 ng/ml and 160 ng/ml the mean survival time was 984 days (p<0.005). Survival-analysis revealed in adenocarcinoma a mean survival of 1152 days in the group below 83 ng/ml. In the median group the mean survival time was 788 days and in the group with the highest levels the mean survival time was 388 days (p<0.001). In contrast, we found no correlation between the FEV1 and the CCL18 baseline level. In conclusion, in patients suffering from adenocarcinoma increased serum CCL18 levels predict a diminished survival time.     

Effect of intraoperative local application of 3% hydrogen peroxide on pocket infections following cardiac implantable electronic device implantation: An observational study

Aims

The aim of this study was to analyze whether local application of 3% hydrogen peroxide (H2O2) additionally to standard antibiotic prophylaxis following implantation of cardiac implantable electronic devices (CIED) reduces the incidence of pocket infections (PI).