Different methods for the evaluation of species of the genus Mesaphorura (Collembola, Tullbergiinae)

Field studies and laboratory investigations based upon cultures, isoenzyme electrophoresis and RAPD-PCR were carried out to get a better understanding of the value of morphospecies within the genus Mesaphorura.Culturing of seven Mesaphorura species under constant as well as variable conditions provided a basis for evaluation of morphological characters, but did not yield any statistically supportable evidence that intraspecific variability reached interspecific delimitations.In enzyme tests, esterases gave the best results. The search for species-specific band patterns is, however, time and material consuming. DNA investigations using RAPD-PCR resulted in band patterns that appeared to be species specific. Nevertheless, these require further investigations.None of the studies carried out gave any conclusive evidence for invalidation of the morphologically defined species of the genus Mesaphorura.     

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).     

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.     

Porcine nephropathy induced by long-term ingestion of ochratoxin A.

Nine pigs were fed crystalline ochratoxin A in their feed at a concentration of about 1 mg/kg. Three pigs and their controls were killed after 3 months and 6 pigs and controls were killed after 2 years. A decrease of the ratio TmPAH/CIn, increased urinary glucose excretion and decreased ability to concentrate urine, occurred within a few weeks and aggravated slightly during the 2-year period. Changes in renal structure, characterized by degeneration and atrophy of proximal tubules, interstitial fibrosis and hyalinization of glomeruli, were progressive during time of exposure, but terminal renal failure was not reached. The kidney, liver, muscular and adipose tissue contained 3 to 27 microgram ochratoxin A/kg after 3 months of exposure. No further accumulation of ochratoxin A residue was found after 2 years of exposure.     

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.