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The potentiometric electronic tongue is a new and rapidly developing technique. However, the description of the exact working mechanism is still absent. An important part of this description is the effect of the sample temperature on the measurement results. The paper reported here gives a description of the effect of temperature on results obtained with an α-Astree potentiometric electronic tongue. The yielded model was used to perform a temperature correction as if the samples were measured at room temperature (25 °c).
Summary
The adsorption kinetics of strontium ion was studied on seven natural clay samples with radioactive tracer method. The kinetic curves were determined and the kinetic data were evaluated by forms of first-rate kinetic equations with different terms, generally used for adsorption of ions of low concentration. The adsorption process was reduced to two steps. Film diffusion and participle diffusion were found in the case of five samples. Gel diffusion, film diffusion and participle diffusion were found in the case of the other two samples. The presence of significant amount of cristobalite can explain the gel phase in these two samples. The rate coefficients of steps were calculated from the kinetic curves.
Growth regulation is a crucial event in tumour progression. Surprisingly, relatively few papers have dealt with the catabolic side of regulation, and there are practically no data regarding the autophagic process during tumour development. We approach this problem by morphometrical investigation into the possi- ble changes of autophagic activity during the progression of rat pancreatic adenocarcinoma induced by azaserine. In the present study, autophagic capacity of the azaserine-induced premalignant and malignant cells were characterised and compared to the respective host tissue cells of the rat pancreas and to the acinar cells in other stages of tumour development. Using vinblastine (VBL) as an enhancer, and cyclo- heximide (CHI) as an inhibitor of autophagic segregation we observed that autophagic capacity of pre- malignant cells (month 6 and 10 after initiation) is much higher than in the host tissue cells. We found a sharp decrease in self-digesting capacity in adenocarcinoma cells (month 20) where VBL induced a min- imal accumulation of autophagic vacuoles which was, surprisingly, not inhibited by CHI, i.e. the CHI- sensitive regulatory step was lost. The changes in autophagic capacity are probably associated to specif- ic steps of tumour progression in our system.
Although much is known about the protective effect of acute estrogen therapy in cerebral ischemia, relatively little is known about the importance of apoptosis and cerebral plasticity in this mechanism. In this work 10 min global cerebral ischemia was produced by transient bilateral carotid occlusion in 4-month-old ovariectomized female gerbils. In every of our experimental group (sham for ischemia group, ischemia group and ischemia + a high, single dose 17β-estradiol pre-treatment group) apoptotic (bcl-Xl, bax) and cerebral plasticity (GAP-43, synapsin-I, nestin) hippocampal genes’ expression was measured four days after surgery. Expression of the anti-apoptotic bcl-Xl (p<0.01) and the cerebral plasticity marker synapsin-I and nestin (p<0.01) increased with acute estrogen pretreatment in ischemic animals. No change, however, in bax or GAP-43 expression was detected in estrogen treated animals compared to ischemic gerbils. These results suggest that acute estrogen therapy has anti-apoptotic effect and increases cerebral plasticity, which play an important role in cytoprotection or cerebroprotection.
Twenty-seven isolates of Phytophthora infestans collected in Hungary in 2001 were tested for mating type, response to metalaxyl, isozyme genotype at glucose-6-phosphate isomerase (Gpi) and peptidase A (Pep) loci and nuclear DNA fingerprints with probe RG57. The ratios of the mating types A1 to A2 were 5:6 and 9:7 among isolates from potato and tomato, respectively. Seventeen isolates were sensitive to metalaxyl, 1 isolate responded intermediately and 9 isolates were resistant. No novel combinations of isozyme alleles were found; all isolates were Gpi 100/100, and genotypes at the Pep locus were 96/96 (63%), 83/96 (11%) and 100/100 (26%). In contrast, all of the 22 RG57 fingerprints exhibited patterns that have not been reported in Hungary before. On the basis of combined traits, 22 multilocus genotypes, unnoted elsewhere in Europe, were constructed among the 27 isolates analysed. These results indicate that variability in the Hungarian P. infestans populations is likely due to local events (asexual and sexual interactions) rather than migration from other countries.
Interannual variation of carbon fluxes of grasslands on sandy (5 years data) and heavy clay soils (4 years data) have been analysed. The sandy grassland was carbon sink in 3 (2004, 2005, 2006) out of the investigated 5 years. Its annual C-balance is precipitation limited, the relation seems strongly conservative, with r 2 of 0.83. More than half of the net source activity fell to the summer droughts. The heavy clay grassland was net source of carbon in one year (2007) only with no whole year record from 2003, a drought and heat wave year. Dependence of the C-balance on precipitation was somewhat weaker (r 2 =0.57) than in the sandy grassland. Length of growing period showed less variation here compared to the sandy grassland. Recovery of sink activity after rains was much slower for the heavy clay grassland than for the sandy grassland. The reason behind is that the amount of water required to reach optimal soil water content for plant functioning is several times larger for the mountain grassland. This fact and the low conductivity of the clay soil for water decrease the heavy clay grassland’s recovery potential after droughts. Owing to these soil characteristics, the clay grassland may be more vulnerable to droughts in terms of decreased C-assimilation and (soil) carbon losses under the predicted drier summers even if the annual precipitation sum was higher by 10.7% on average for the mountain compared to the sandy grassland. The annual precipitation sum is close to the threshold, below which the grasslands may turn into source of carbon. While in one hand this can be viewed as an example of ecosystem scale adaptation to available water, drought events also involve loss of soil carbon and a potential positive feedback between source activity and decreasing net primary production, on the other.
A neighbourding -quadrate transect study was conducted in order to examine the possibile relationship between small scale topography and coenotaxa occurrence and cover in subassociations of Festucetum vaginataeRapaics ex Soó 1929 sandy grassland plant community near Fülöpháza. These investigations served as a starting point in later soil seed bank studies. Cover of species was recorded in three transects of different exposition starting on the top of different dunes and ending in the depressions. Subassociations and facies forming species of the community occurred in all investigated transects. Parts of the transects could not have been classified unambiguously into any of the coenotaxa mentioned in the literature. In these zones the charactersitic species of the different subbasociations and facies were occurding together. These patches are propbably also the ones where changes in dominance relations and simultaneous spread of a species can relatively easily happen, as it is the case with Cleistogenes serotina. Annual vegetation of the open sandy grassland, ond the other hand, has occured only in the transition zones, between the subassociations or facies. In these transects moss-lichen synusia were peresent usually in the subassociation Festucetum vaginatae pennatae Kerner 1863.
Remnants of the former semiarid forest-steppe vegetation of Hungary are suspected to undergo degradation processes because of recent land-use changes. Secondary succession towards closing of the vegetation starts with shrub invasion, mainly with species of the shrub layer of loess steppe oak forest. Soil respiration (SR) activity of the intercanopy loess grassland community was followed occasionally along of six years period, as well as the spatial patterns of SR and soil water content (SWC) with three direct measuring campaigns. Dependence of SR on SWC-soil temperature was statistically significant for the six years period, but the rest of the variance should be explained by other factors, as found for normalized difference vegetation index. In the spatial analysis, significant differences were found in the ranges of semivariograms according to the seasonal variation of soil moisture content. Larger scale patches were found under summer water stress (4 m for SR, 2.6 m for SWC) and autumn senescence (3.8 m for SR, 1.3 m for SWC) periods than under well-watered, peak performance summer circumstances (0.8 m for SR, 0.6 m for SWC). This suggests that homogeneity of patterns is typical at good water supply, while coarse-grained patches prevail under drought stress.
The performance of a semisynthetic bisexual lure (SBL, containing isoamyl alcohol, acetic acid and red wine) previously found attractive for a number of noctuids was compared with that of the respective synthetic sex attractants of Orthosia cerasi (=stabilis), O. cruda, O. gothica, O. incerta, Anorthoa munda and Conistra vaccini. The respective sex attractants performed significantly better in the Orthosia spp. than the SBL lure, which, although regularly catching low numbers of both females and males, did not differ significantly from zero catch in unbaited control traps. On the other hand, the SBL lure performed as well as the sex attractant in C. vaccini. Sizeable catches of C. rubiginea, C. rubiginosa and C. erythrocephala were also recorded in traps with the SBL lure. The SBL lure can prove to be a useful tool in ecological and faunistical studies of Conistra and related hibernating Xylenini species.
