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The possibilities latent in molecular marker-based QTL analyses are presented through the example of studying winter survival and heading date in barley (Hordeum vulgare L.). The whole range of QTL experiments consists of several important steps, through which answers are found to the following questions: (1) How many QTLs are involved and where do they map, (2) How does the environment influence the effect of a QTL region (environment × QTL interactions), (3) When and where are the genes determining the given trait expressed (QTL dynamics), (4) What interactions occur between these QTLs and pathways leading to specific phenotypes, and (5) How consistent is the effect of a QTL region in different genetic backgrounds and in a wider range of germplasms (comparative mapping and association studies)? This knowledge then makes it possible to continue these experiments in the direction of marker-assisted selection and/or gene isolation through marker saturation of the relevant chromosomal regions and map-based cloning. The latter can give an insight into the exact mechanism through which the gene determines the phenotype.
The effect of soil tillage on the yield and quality of flue-cured tobacco was studied from 1998 to 2001 at the Experimental Station of the Tobacco Institute Zagreb in Croatia. The trial soil was a Luvisol with an acid reaction and a low content of colloids and organic matter. There were three treatments in the experiment: 1. autumn ploughing, 2. spring ploughing, and 3. autumn ploughing + chisel ploughing in spring. The treatments were arranged in random blocks with four replications. Soil ploughed in both autumn and spring gave higher yields of flue-cured tobacco in comparison with autumn ploughing alone. Soil ploughed only in autumn became compacted due to settling during the winter and spring because of the unstable structure and unfavourable texture.
The toxic heavy metal concentrations were investigated in plants in a meadow located 51 kilometres from Budapest along the M3 motorway. The field is regularly harvested, and the hay is used as fodder. The area under investigation is situated directly alongside the protecting fence of the motorway. The soil of the area is classified as chernozem brown forest soil. In 2000 approximately 22,860 cars per month travelled on the motorway. The plant samples were taken at a distance of 5, 10, 25, 50 and 100 metres from the motorway. At each distance 10 samples were collected. After digestion with hydrogen peroxide and nitric acid the zinc, lead, cadmium and copper contents of the samples were analysed using an ICP spectrophotometer. After analysing the data it was established that for each of the heavy metals the concentration of metal in the plant samples decreased as the distance from the motorway grew. The measured zinc, cadmium and copper concentrations were similar to those reported by other authors (on average 44.9, 0.276 and 5.25 mg kg-1), while the values of the lead concentration were lower than those published previously (on average 2.93 mg kg-1). This may have been due to the widespread use of lead-free fuel.
Saline irrigation water has a tremendous impact on the yield potential of crops. The distribution of mineral elements and their ratios in maize plant organs in response to saline water and nitrogen (N) nutrition was studied in a pot experiment for six weeks. The plants were separated into leaf, stalk and root and analysed for calcium (Ca), magnesium (Mg), sodium (Na), potassium (K) and chloride (Cl) contents. The partitioning and ratios of mineral nutrients in plants were significantly affected by water salinity and nitrogen level. In saline water the roots contained the highest Na content; Ca and Mg were higher in the leaf, whereas K and Cl were highest in the stalk. In non-saline water, Na and Cl were highest in the root and the remaining elements were greatest in the stalk. The K and Cl contents were significantly reduced by an increase in the N level, whereas the reverse was true for the Ca, Mg and Na contents. An inverse relationship was noted for the plant biomass versus both Na uptake and the Na/Ca, Na/Mg and Na/K ratios in plants irrigated with saline water. The mineral elements, with the exception of K, appeared to be highly correlated in the plant parts.
New wheat × barley, wheat × Aegilops biuncialis and wheat × rye hybrids were produced with the aim of alien gene transfer from these species into wheat. Amphiploids were produced with the help of colchicine treatment from the last two combinations. The new wheat × barley hybrids were multiplied in tissue culture because of the high degree of sterility and then pollinated with wheat to obtain backcross progenies. Wheat-barley chromosome pairing was detected using genomic in situ hybridization (GISH) in two combinations (Mv9 kr1 × Igri, Asakazekomugi × Manas). In vitro conditions caused an increase in chromosome arm association frequency in both combinations and in fertility in some regenerants. Five wheat-barley translocations were produced in a wheat background and characterized through the combination of cytogenetic and molecular genetic approaches (GISH, FISH and SSR markers). The following translocations were identified: 2DS.2DL-1HS, 3HS.3BL, 6BS.6BL-4HL, 4D-5HS and 7DL.7DS-5HS. Physical mapping of the SSR markers on chromosomes 1H and 5H was carried out using the intragenomic and interspecific translocation breakpoints and the centromere as physical landmarks. Disomic wheat-Aegilops biuncialis additions were produced after backcrossing the wheat-Ae. biuncialis amphiploids. Fluorescence in situ hybridization (FISH) was carried out using two repetitive DNA clones (pSc119.2 and pAs1) on Ae. biuncialis and its two diploid progenitor species to detect chromosome polymorphism. The 7M and 3M disomic chromosome additions were selected and five more lines still need to be characterized. The octoploid triticale (Mv9 kr1 × Lovászpatonai) produced in Martonvásár was crossed with a 1RS.1BL wheat cultivar Matador. GISH analysis detected pairing between the 1RS arm of the translocation chromosome and that of Lovászpatonai rye in 32 % of the pollen mother cells, making it possible to select recombinants from this combination. The new recombinants between the 1RS of Petkus and the 1RS of Lovászpatonai rye cultivars are being analysed with the help of microsatellite markers.
The aim of this study was to examine the effects of asphyxia-reventilation and hyperoxia on the cerebral blood perfusion and prostanoid production of the brain arteries and microvessels in piglets. After 10 min of asphyxia, animals were ventilated with room air, or with 100% O2. Following 4 hours of recovery, the brains were perfused, cerebral arteries were removed and microvessels were isolated from the cortex. The microvessels and the arteries were incubated with 1-14C-arachidonic acid, and the 1-14C-prostanoids were then separated by means of overpressure thin-layer chromatography and were quantitatively determined. Under control conditions, the synthesis of dilatory prostanoids dominated the arachidonate cascade both in the microvessels and in the arteries. Asphyxia and reventilation with room air did not modify the prostanoid production. O2ventilation greatly affected the prostanoid synthesis of the microvessels, with an enhancement of PGD2up to 247±27%. In the arteries, the production of PGI2and of PGE2was elevated to 272±15% and to 148±13%, respectively. These findings indicate that O2ventilation after asphyxia substantially increases the extent of prostanoid synthesis in the cerebral blood vessels._
Molecular mechanisms of the action of b-lactam and glycopeptide antibiotics, as well as genetic background and phenotipical features of the resistance of staphylococci, streptococci and enterococci to these antibiotics are reviewed. Furthermore, susceptibility patterns concerning b-lactam and glycopeptide drugs of staphylococcal, streptococcal, as well as enterococcal strains isolated from clinical specimens at the Semmelweis University of Medicine, Budapest, Hungary between January 1997 and December 2000 are also presented.
The authors' hypothesis is that the members of the tricarboxylic acid cycle (TCA cycle) such as citrate decrease in association with increased ketone body formation. To prove this hypothesis the connection between ketone bodies and citrate formation of milk was studied. A fluorimetric method was used to determine citrate and a headspace sampling gas chromatographic (GC) method was developed for determination of ketone bodies. Under real conditions of milk sampling, transport and storage, preserved milk samples of 119 clinically healthy dairy cows obtained in the 48 hours after milking were investigated. A low level of acetoacetate (ACAC) was found in all samples. This fact can be explained by the spontaneous decarboxylation of acetoacetate during sample storage (previously decarboxylised acetoacetate = pdACAC) and, consequently, the majority of the amount of acetoacetate in the samples (AC+pdACAC) appeared in the measured acetone concentrations. Based on the measured acetone concentration of milk samples two groups were formed retrospectively: HA (high-acetone) group (n = 41) with an AC+pdACAC concentration of ≯ 0.4 mmol/l and a LA (low-acetone) group (n = 78) with an AC+pdACAC level of ≤ 0.4 mmol/l. In the milk of cows of Group HA a positive correlation (r = +0.623) and linear connection between acetone (AC+pdACAC) and β-hydroxybutyrate (BOHB) levels was found [BOHB = 2.491 + 0.586 × (pdAC + ACAC)]. Furthermore, in this group a negative correlation between citrate and BOHB and AC+pdACAC was also established (r = -0.579). Focusing on the results of this group the authors found a significant drop of AC+pdACAC and citrate during the metabolically critical first 1-4 weeks of lactation. For this reason they suggest that simple, easy, automated methods (i.e. flow injection analysis, Fourier transformation infrared analysis) should be introduced for the simultaneous determination of acetone and citrate concentration in milk to make the evaluation of the energy status of high-producing dairy cows easier and more certain.
Anatomical and physiological properties of the digestive tract were examined and compared in young rabbits nursed either by one (SS) or by two does (DD) daily up to the age of 35 days. At the age of 23, 30, 37 and 44 days, 8 young per treatment were euthanised. Double suckling and the subsequent higher level of solid feed intake after weaning were found to exert a stronger influence on the weight of the entire gastrointestinal tract and that of its individual parts (the stomach, small intestine, caecum and colon) than on its length. The quantity of the gastric content was found to rise with advancing age in both groups (from 36 to 70g and from 37.5 to 79g). In both groups the pH of the stomach was higher during the suckling period (4.5-5.3) than subsequent to weaning (1.6-2.4). The quantity of the caecal content also increased with age (from 4 or 8g), but on the 37th day significantly higher quantities of caecal content were recorded in DD rabbits (50.5g compared with 35g). The pH of the caecal content decreased more slowly from an initial high value (6.0 and 6.5 in SS and DD rabbits, respectively), and by the 37th day had settled at a low value (5.7-5.8) in both groups. The dry matter content of the caecal content decreased from 270-273g to 188-207g in both groups. Total volatile fatty acid (tVFA) and acetic acid (C2) concentration, which amounted to 66-88% of tVFA, rose; in SS rabbits they were at higher levels by the 30th day (53.6 and 42.2mmol/L, respectively), and remained at an increased level until the 44th day (P<0.05). The ratio of C3:C4 was high on the 23rd day (2.5 and 2.4), but dropped at the age of 30 days (0.5 in SS and 1.7 in DD, P<0.05) and, further, by the 37th day (0.2 in SS). In SS rabbits coliform count proved significantly lower (105) on the 23rd day than in DD rabbits (106). By the 37th day this count had decreased in both groups and subsequently remained at a low level (<104). By the 23rd day Bacteroides were present in large quantities (108) in the caecum and showed no change with advancing age or feeding regime.
Left ventricular systolic function was assessed in 12 healthy dogs with equilibrium radionuclide ventriculography. The results of the analysis were compared to traditional echocardiographic measurements. Left ventricular internal dimensions and volume were measured at the time of end-systole and end-diastole. Ejection fraction - one of the most informative parameters of cardiac function - was calculated in each animal. Values (e.g. EDD, ESD, EDV, ESV) measured by the scintigraphic method were significantly (Student's t-test, P < 0.05) higher than the data obtained by echocardiography. Ejection fraction (EF) was the only parameter that did not differ significantly when comparing the two imaging techniques. The difference between the results of parallel measurements was in inverse ratio to the size of the heart.
