Discrete coding of reward probability and uncertainty by dopamine neurons

Uncertainty is critical in the measure of information and in assessing the accuracy of predictions. It is determined by probability P, being maximal at P = 0.5 and decreasing at higher and lower probabilities. Using distinct stimuli to indicate the probability of reward, we found that the phasic activation of dopamine neurons varied monotonically across the full range of probabilities, supporting past claims that this response codes the discrepancy between predicted and actual reward. In contrast, a previously unobserved response covaried with uncertainty and consisted of a gradual increase in activity until the potential time of reward. The coding of uncertainty suggests a possible role for dopamine signals in attention-based learning and risk-taking behavior.     

Structure of the rotor ring of F-Type Na+-ATPase from Ilyobacter tartaricus

In the crystal structure of the membrane-embedded rotor ring of the sodium ion-translocating adenosine 5'-triphosphate (ATP) synthase of Ilyobacter tartaricus at 2.4 angstrom resolution, 11 c subunits are assembled into an hourglass-shaped cylinder with 11-fold symmetry. Sodium ions are bound in a locked conformation close to the outer surface of the cylinder near the middle of the membrane. The structure supports an ion-translocation mechanism in the intact ATP synthase in which the binding site converts from the locked conformation into one that opens toward subunit a as the rotor ring moves through the subunit a/c interface.     

Towards breeding of triploid chamomile (Matricaria recutita L.) – Ploidy variation within German chamomile of various origins

German chamomile is an important medical plant with a long history of usage and a wide range of medical applications. Wild forms are diploid, whereas cultivated ones are diploid and tetraploid. Ploidy level variation within 15 origins (varieties, accessions, populations) of chamomile was investigated. Both naturally occurring triploids and those induced through directed crosses between diploid and tetraploid parents were identified and analysed, and these data could facilitate the exploitation of triploidy in chamomile as in other crop plants (fruit and ornamental plants).     

Yield and fruit development in mango (Mangifera indica L. cv. Chok Anan) under different irrigation regimes

‘Chok Anan’ mangoes are mainly produced in the northern part of Thailand for the domestic fresh market and small scale processing. It is appreciated for its light to bright yellow color and its sweet taste. Most of the fruit development of on-season mango fruits takes place during the dry season and farmers have to irrigate mango trees to ensure high yields and good quality. Meanwhile, climate changes and expanding land use in horticulture have increased the pressure on water resources. Therefore research aims on the development of crop specific and water-saving irrigation techniques without detrimentally affecting crop productivity.The aim of this study was to assess the response of mango trees to varying amounts of available water. Influence of irrigation, rainfall, fruit set, retention rate and alternate bearing were considered as the fruit yield varies considerably during the growing seasons. Yield response and fruit size distribution were measured and WUE was determined for partial rootzone drying (PRD), regulated deficit irrigation (RDI) and irrigated control trees.One hundred ninety-six mango trees were organized in a randomized block design consisting of four repetitive blocks, subdivided into eight fields. Four irrigation treatments have been evaluated with respect to mango yield and fruit quality: (a) control (CO = 100% of ET_c), (b) (RDI = 50% of ET_c), (c) (PRD = 50% of ET_c, applied to alternating sides of the root system) and (d) no irrigation (NI).Over four years, the average yield in the different irrigation treatments was 83.35 kg/tree (CO), 80.16 kg/tree (RDI), 80.85 kg/tree (PRD) and 66.1 kg/tree (NI). Water use efficiency (WUE) calculated as yield per volume of irrigation water was always significantly higher in the deficit irrigation treatments as compared to the control. It turned out that in normal years the yields of the two deficit irrigation treatments (RDI and PRD) do not differ significantly, while in a dry year yield under PRD is higher than under RDI and in a year with early rainfall, RDI yields more than PRD. In all years PRD irrigated mangoes had a bigger average fruit size and a more favorable fruit size distribution.It was concluded that deficit irrigation strategies can save considerable amounts of water without affecting the yield to a large extend, possibly increasing the average fruit weight, apparently without negative long term effects.     

Investigations concerning the use of the rumen fermentation regulator monensin in feeding fattening bulls

In two digestion experiments with wethers and seven feeding experiments with 198 fattening bulls with rations rich in (greater than 55% of the dry matter intake from roughage), the influence of the antibiotic monensin on the digestibility of the ration, on rumen-physiologic characteristic values and on fattening and slaughtering results was investigated. The digestibility of the organic matter and the crude nutrients was not significantly influenced by the use of monensin (20 mg/kg dry matter). The administration of 200 mg monensin per fattening bull and day resulted in an increase of the molar concentration of propionate in the rumen fluid by 9.7 mol%, the concentration of acetate and butyrate decreased by 7.3 resp. 2.8 mol %. On an average of the seven experiments the intake of dry matter was diminished by 5.1% through the use of monensin, the live weight increase remained almost unaffected (3.0% additional increase), feed and energy requirement per kg live weight were improved by 7.9%. The fattening results do not always correspond in the various experiments. The results of the dressing of the carcass, the composition of the carcass and the quality of the meat remained unaffected by the administration of monensin.     

Rabies in a 10-week-old puppy

A 10-week-old, male, border collie-cross puppy was examined for an acute onset of unilateral vestibular signs. Neurologic deterioration was rapid over the next 12 hours and the puppy was euthanized. Rabies was diagnosed by histopathologic and immunohistochemical examination.     

Estimating the mass of mango fruit (Mangifera indica, cv. Chok Anan) from its geometric dimensions by optical measurement

Uniform fruit mass and shapes of mangoes for export are required in order to ease handling and transportation, and to help satisfy consumer preferences. However, with its irregular shape, one which cannot be approximated by using standard geometrical figures, the mango is not as easy to model as round or oval-shaped fruits.In this study, more than 1000 mango ‘Chok Anan’ fruit were measured with respect to their length, maximum width and maximum thickness, to within an accuracy of 1.0  mm, and their weight was determined to within an accuracy of 0.1  g. Pictures were taken of 30 fruit, through the use of digital cameras, manually rectified and analyzed by use of “Measure 2.1” a computer code.An equation was proposed in order to calculate the mass of the mangoes based on three geometric dimensions, which then showed a high level of explanatory power of R² = 0.97. The root mean standard error of 12.22 was determined, and the mean relative deviation found was 0.05. Based on measurements taken from the digital photos, the equation was then used to determine the estimated mass based on three dimensions. Estimated and measured values were plotted against each other. A high correlation (R² = 0.96) was found between measured and calculated mass.It was shown that the mass can be estimated based on data obtained from two orthogonally taken photographs.     

Dendroecological assessment of the complex causes of decline and recovery of the growth of silver fir (Abies alba Mill.) in Southern Germany

Causes of decline and silver fir (Abies alba Mill.) mortality in Central Europe have been controversially discussed for a long time. This contribution details a comprehensive dendroecological investigation of two basic and alternative hypotheses that explain the decline by either climatic influences or by SO₂ pollution as the primary factors. Growth reduction between the 1960s and 1980s as well as the recovery of growth during recent decades have be seen as a response to complex interactions of multiple factors. Herein, we undertake a multidisciplinary evaluation of a broad database, representing the long-term growth of 1010 firs from 51 sites, long-term climate records as well as data assessing the long-term pollution situation in Southern Germany. The results provide clear evidence that SO₂-immissions play a key role in decline and that tree growth corresponds with the regional and temporal pattern of SO₂ pollution. Calculations with a new complex growth model indicate that tree-ring widths of fir at many sites were more influenced by SO₂ than by any other growth-determining factor during the second half of the last century. Strongest coherence between measured and modelled ring widths are found if – in addition to temperature, available soil water content, heavy frost events and long-term growth trends – the site-specific trend of SO₂ pollution is included. Both the immediate response to SO₂ pollution and the quick recovery of fir since the beginning of the 1980s after the decrease of SO₂ emissions indicate a direct impact of SO₂ in gaseous form and not via the soil in terms of soil acidification. Tree-ring widths document that radial growth response occurs at air concentrations above 10 μg SO₂ m⁻³ (annual average), which can be thought of as a critical threshold for silver fir health. Since the beginning of the 1980s, increasing growth trends have been observed which predominantly result from decreased SO₂ pollution in most parts of Central Europe, although climate change, fertilization by nitrogen deposition and a reduced tree-to-tree competition are also relevant factors. The drastic reduction of SO₂ emission during the recent decades significantly improved the environmental conditions for fir. Consequently, an increased cultivation of silver fir on suitable sites is recommended.     

Escherichia coli, but not Staphylococcus aureus triggers an early increased expression of factors contributing to the innate immune defense in the udder of the cow

The outcome of an udder infection is influenced by the pathogen species. We established a strictly defined infection model to better analyze the unknown molecular causes for these pathogen-specific effects, using Escherichia coli and Staphylococcus aureus strains previously asseverated from field cases of mastitis. Inoculation of quarters with 500 CFU of E. coli (n = 4) was performed 6 h, 12 h, and 24 h before culling. All animals showed signs of acute clinical mastitis 12 h after challenge: increased somatic cell count (SCC), decreased milk yield, leukopenia, fever, and udder swelling. Animals inoculated with 10 000 CFU of S. aureus for 24 h (n = 4) showed no or only modest clinical signs of mastitis. However, S. aureus caused clinical signs in animals, inoculated for 72 h-84 h. Real-time PCR proved that E. coli inoculation strongly and significantly upregulated the expression of beta-defensins, TLR2 and TLR4 in the pathogen inoculated udder quarters as well as in mammary lymph nodes. TLR3 and TLR6 were not significantly regulated by the infections. Immuno-histochemistry identified mammary epithelial cells as sites for the upregulated TLR2 and beta-defensin expression. S. aureus, in contrast, did not significantly regulate the expression of any of these genes during the first 24 h after pathogen inoculation. Only 84 h after inoculation, the expression of beta-defensins, but not of TLRs was significantly (> 20 fold) upregulated in five out of six pathogen inoculated quarters. Using the established mastitis model, the data clearly demonstrate a pathogen-dependent difference in the time kinetics of induced pathogen receptors and defense molecules.