Michael Collinson. A History of Farming Systems Research     

Graham Thiele 《Agriculture and Human Values》2002,19(4):365-366

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Breeding strategies to increase fitness in poultry     

Thiele HH 《DTW. Deutsche tier?rztliche Wochenschrift》2001,108(3):140-144

The performance of the meat type hybrids of today is much higher than at the beginning of the century. Antagonistic relations between the polygenic performance traits and fitness are the reason why modern hybrids need optimal management conditions, their susceptibility to stress increased and their immunocompetence decreased. There will be discussed, how modern genetics is counteracting by using new selection techniques.  相似文献   

Gluten hydrolysis and depolymerization during sourdough fermentation     

Thiele C  Grassl S  Gänzle M 《Journal of agricultural and food chemistry》2004,52(5):1307-1314

Hydrolysis and depolymerization of gluten proteins during sourdough fermentation were determined. Neutral and acidified doughs in which microbial growth and metabolism were inhibited were used as controls to take into account the proteolytic activity of cereal enzymes. Doughs were characterized with respect to cell counts, pH, and amino nitrogen concentrations as well as the quantity and size distribution of SDS-soluble proteins. Furthermore, sequential extractions of proteins and analysis by HPLC and SDS-PAGE were carried out. Sourdough fermentation resulted in a solubilization and depolymerization of the gluten macropolymer. This depolymerization of gluten proteins was also observed in acid aseptic doughs, but not in neutral aseptic doughs. Hydrolysis of glutenins and occurrence of hydrolysis products upon sourdough fermentation were observed by electrophoretic analysis. Comparison of sourdoughs with acid control doughs demonstrated that glutenin hydrolysis and gluten depolymerization in sourdough were mainly caused by pH-dependent activation of cereal enzymes.  相似文献   

Assessment of the soil phosphorus–mobilization potential by microbial reduction using the Fe(III)‐reduction test     

Sren Thiele‐Bruhn 《植物养料与土壤学杂志》2006,169(6):784-791

The mobility of soil P is greatly influenced by the redox potential (Eh), which depends on the reducing activity of soil microorganisms. Standard extraction methods for the determination of the mobile soil P disregard the P mobilization caused by the influence of microorganisms on Eh, while P test methods that include soil microbial activities are lacking. Thus, the Fe(III)‐reduction test was investigated for its suitability to determine the P fraction that is mobilized in soil under reducing conditions (P_Red). In this test, the soil‐microbial reducing activity is measured from the microbial Fe(III) reduction combining a bioassay with 7 d incubation and a chemical extraction using 1M KCl. After the incubation, Eh in 26 different soil samples ranged from –282 to –123 mV. The concentration of P_Red in the soil samples ranged from concentrations below the limit of detection to 84.9 mg kg^–1 and was on average of all soil samples by a factor of 2.4 to 18 smaller than the P fractions determined by standard soil P–extraction methods. As standard agronomic and environmental P extractants, respectively, water (P_H2O), dithionite citrate bicarbonate (P_Dith), ammonium oxalate (P_Ox), ammonium lactate (P_AL), double lactate (P_DL), and sodium bicarbonate (P_Olsen) were selected. The P_Red fraction was not correlated with P_AL, P_DL, P_olsen, and the degree of P saturation, but with P_H2O (r = 0.43*), P_Dith (r = 0.60***), and P_Ox (r = 0.61***). Furthermore, P_Red depended on the concentration of amorphous Fe oxides (Fe_Ox, r = 0.53**) and was closely correlated with the concentration of microbially reduced Fe (Fe_Red, r = 0.94***). This indicated the influence of the Fe(III)‐reducing activity of soil microorganisms on P mobilization. In subsoils, low in Fe(III)‐reducing activity, no P was released by the Fe(III)‐reduction test, which was in contrast to the results from the other chemical extraction methods. Additional alterations of the microbial activity by inhibiting and activating amendments, respectively, clearly affected the microbial Fe(III)‐reducing activity and the associated release of P_Red. Thus, P_Red, determined by the Fe(III)‐reduction test, might be termed as the fraction that is potentially released from soil by microbial reduction.  相似文献   

Time‐resolved in‐situ pH measurement in differently treated,saturated and unsaturated soils          下载免费PDF全文

Sören Thiele‐Bruhn  Stefan Wessel‐Bothe  Marc‐Oliver Aust 《植物养料与土壤学杂志》2015,178(3):425-432

The pH‐value is of utmost relevance for soil properties and functioning. Hence, a time‐resolved in‐situ measurement is mandatory but lacking. As an alternative, a two‐probe pH electrode with gel‐covered reference electrode was newly constructed and tested for a continuous, in‐situ pH recording in saturated and unsaturated soil. This was done using samples from a set of 14 soils with different composition and pH$ _{\rm CaCl_2} $ ranging from 3.5 to 7.5 in batch and repacked soil column experiments. In the latter, changes in pH and redox potential were monitored upon transport of citrate‐phosphate buffer and pig slurry through the soil columns. The pH measurements were largely stable even upon substantial shifts in soil moisture content down to air‐dry conditions. The results of the pH measurements agreed with standard methods using settled soil suspensions in electrolyte solutions and the conventional combination (single‐probe) pH electrode. Testing the suspension effect, it was found that measuring pH directly in the soil is recommended. The pH measured in‐situ was closest to pH values determined in 0.01 M CaCl₂ suspensions according to DIN ISO 10390 (DIN, 2005 ). The transport of citrate buffer and pig slurry as pH active substances through soil induced strong effects on the pH and in part on the redox potential; the reversible effects lasted over days, which may affect the mobility and speciation of nutrients and pollutants as well as microbial processes.  相似文献   

Neural mechanisms of saccadic suppression     

Thiele A  Henning P  Kubischik M  Hoffmann KP 《Science (New York, N.Y.)》2002,295(5564):2460-2462

In normal vision our gaze leaps from detail to detail, resulting in rapid image motion across the retina. Yet we are unaware of such motion, a phenomenon known as saccadic suppression. We recorded neural activity in the middle temporal and middle superior temporal cortical areas during saccades and identical image motion under passive viewing conditions. Some neurons were selectively silenced during saccadic image motion, but responded well to identical external image motion. In addition, a subpopulation of neurons reversed their preferred direction of motion during saccades. Consequently, oppositely directed motion signals annul one another, and motion percepts are suppressed.  相似文献   

Effects of DDT and its metabolites on soil algae and enzymatic activity   总被引：1，自引：0，他引：1  

M. Megharaj  H. L. Boul  J. H. Thiele 《Biology and Fertility of Soils》1999,29(2):130-134

 The persistence of DDT [1,1,1-trichloro-2,2-bis(p-chlorophenyl)ethane] and its metabolites in soil, their toxicity to soil algae, and effects on microbial activities were studied in laboratory microcosms for 45 days. In non-sterile soils, removal of DDD [1,1-dichloro-2,2-bis(p-chlorophenyl)ethane] and DDE [1,1-dichloro-2,2-bis(p-chlorophenyl)ethylene] was less than 3%, while 4–8% of applied DDMU [1-chloro-2,2-bis(p-chlorophenyl)ethylene], DDA [2,2-bis(p-chlorophenyl)acetic acid] and DDT were lost. Added DDOH [2,2-bis(p-chlorophenyl)ethanol] was more labile, as 60% was degraded during the same period. Soil microalgae were not measurably affected by the compounds tested at 10–50 mg kg^–1, but at 100 mg kg^–1 soil, DDD, DBP (p,p′-dichlorobenzophenone) and DDA significantly reduced their growth. Phosphatase activity was not affected by DDT and its metabolites at the concentrations tested (≤50 mg kg^–1), but all compounds inhibited dehydrogenase activity at concentrations of 50 mg kg^–1 soil. The toxic effects of DDT and its metabolites were dose-related. Received: 9 January 1998  相似文献   

Adsorption of the antibiotic pharmaceutical compound sulfapyridine by a long‐term differently fertilized loess Chernozem     

Sren Thiele 《植物养料与土壤学杂志》2000,163(6):589-594

Residues of antibiotic pharmaceutical compounds (APCs) found in the environment are suspected to be translocated into the food chain and to provoke the formation of resistant microorganisms. However, the behavior of APCs in soils is largely unknown. In the present study batch experiments were carried out with sulfapyridine (SPY) and p‐aminobenzoic acid (ABA) amended to two loess Chernozem samples. Due to different fertilization in the course of a long‐term field experiment samples differed substantially in the concentration of organic carbon (C_org 1.6 and 2.4%) and composition of soil organic matter (SOM). APCs in soil extracts were analyzed by high performance liquid chromatography. The K_F values of the Freundlich isotherm for SPY were 2.2 (1.6% C_org) and 5.5 (2.4% C_org). The K_oc values were 101 and 308. The different K_oc values indicated that not only the quantity but also the composition of SOM affected the SPY adsorption. Adsorption of SPY was substantially higher in moist than in air‐dry soil. ABA, consisting of a carboxyl group instead of the sulfonamide group substituted with a N‐heterocycle, was much less adsorbed than SPY (K_F 0.2). From this it was concluded that the N‐heterocycle significantly contributed to the adsorption of SPY.  相似文献   

Contribution of Sourdough Lactobacilli,Yeast, and Cereal Enzymes to the Generation of Amino Acids in Dough Relevant for Bread Flavor     

C. Thiele  M. G. Gnzle  R. F. Vogel 《Cereal Chemistry》2002,79(1):45-51

The amino acid release was determined in wheat doughs supplied with salt, acid, dithiothreitol, or starter cultures to evaluate the relevance of the amino acid concentration on bread flavor. Wheat flour proteinases almost linearly released amino acids and the highest activity of wheat flour proteinases was found in acidified and reduced doughs. The effects of starter cultures on amino acid concentrations depended on their composition. Yeasts exhibited a high demand for amino acids, however, the total amino acid concentrations were not markedly affected by lactic acid bacteria. The individual amino acid contents were determined by the pH during fermentation and microbial metabolism. The formation of proline was favored by values higher than pH 5.5, whereas release of phenylalanine, leucine and cysteine mainly occurred at lower pH. Ornithine was found only in doughs fermented with Lactobacillus pontis. To determine effects of the amino acid concentration on bread aroma, fermented doughs were evaluated in baking experiments. An increased intensity of bread flavor was obtained by preferments prepared with lactic acid bacteria. The roasty note of wheat bread crust could be markedly enhanced by L. pontis. This results support the assumption that flavor of wheat bread is enhanced by increasing the concentration of free amino acids and especially ornithine in dough.  相似文献