Activation of the receptor 5-HT1A increases the rate of neurogenesis in the subventricular zone (SVZ) and its blocking reduces it. Cells generated in the SVZ settle in the olfactory bulb as its interneurons. We investigated in laboratory opossums if changes in the rate of SVZ neurogenesis infl uence olfactory detection of food and discrimination of conspecifi c odors. Four groups of one year old opossums were tested. The fi rst group was injected i.p. for 7 days with saline, the second group with 5-HT1A receptor agonist 8-OH-DPAT, the third group with partial agonist buspirone and the fourth group with the antagonist, WAY100635. BrdU was injected as a marker of newly generated cells. One month later opossums had to locate crickets hidden in the litter. Pretreatment with WAY100635 signifi cantly extended time needed for location of the hidden food in comparison to other groups. Next opossums were exposed for two days to samples of urine of two other opossums. Time of investigation of samples decreased with experience. Opossums injected with buspirone or WAY100635 investigated probes for a longer time and buspirone-treated approached them more frequently. There were no preferences for investigation of new odors. Post mortem investigation of the numbers of BrdU-labeled cells showed predictable differences. These results indicate that reduction of the rate of neurogenesis hampers olfactory detection of food, but detection of odors of conspecifi cs is infl uenced in more complex way
We describe the spatial variability of snow accumulation on three selected glaciers in Spitsbergen (Hansbreen, Werenskioldbreen and Aavatsmarkbreen) in the winter seasons of 1988/89, 1998/99 and 2001/2002 respectively. The distribution of snow cover is determined by the interrelationships between the direction of the glacier axes and the dominant easterly winds. The snow distribution is regular on the glaciers located E-W, but is more complicated on the glaciers located meridionally. The western part of glaciers is more predisposed to the snow accumulation than the eastern. This is due to snowdrift intensity. Statistical relationships between snow accumulation, deviation of accumulation from the mean values and accumulation variability related to topographic parameters such as: altitude, slope inclination, aspect, slope curvature and distance from the edge of the glacier have been determined. The only significant relations occured between snow accumulation and altitude (r = 0.64-0.91).
In adult mammals cells generated in the subventricular zone (SVZ) migrate to olfactory bulbs (OB). Functional significance of this continuous neurogenesis is not clear. We injected opossums (Monodelphis domestica) for seven consecutive days with a 5HT1A agonist (8-OH-DPAT or buspirone), or its antagonist WAY100635. One hour after each of these injections bromodeoxyuridine (BrdU), a marker of dividing cells was also injected. Two months later, when newly generated neurons settled in the OB and matured the ability of these opossums to detect hidden food by olfactory cues was tested. Afterwards, numbers of BrdU-labeled cell nuclei in their OB were counted and a phenotype of labeled cells established. In all groups investigated the majority of new cells differentiated into neurons (55-76%) and a lower proportion into astroglia (6-12%). Numbers of BrdU-labeled cells differed depending on the applied treatment: both agonists of the 5HT1A receptor increased these numbers, while its antagonist decreased them. The increased number of new OB interneurons did not change the time required for finding all three food items and therefore did not improve the opossums' performance in this test of the olfactory perception. However, opossums that had the reduced number of new generated OB cells searched longer for each food item and in consequence took three times longer to find all three crickets, than did opossums from other groups. In conclusion, lower numbers of new neurons in the opossums OB correlated with their worse behavioral performance in a test based on olfactory perception.
INTRODUCTION: MMP‑9‑1562C/T modulates MMP‑9 mRNA expression and consequently influences the course of many human diseases that involve pathology of this metalloproteinase (e.g., stroke, Alzheimer’s disease, Parkinson’s disease, multiple sclerosis, cardiovascular diseases). Until now, the precise molecular mechanism of MMP‑9‑1562C/T‑dependent influence on MMP‑9 gene expression has not been discovered. AIM(S): The purpose of this study is to identify transcriptional regulators binding to MMP‑9‑1562C/T and to evaluate their influence on MMP‑9 expression in human neurons. METHOD(S): The studies are carried out in differentiated neurons derived from the SH-SY5Y human neuroblastoma cell line. We showed, by luciferase assay, that transcriptional activity of the T allele is higher than the C allele in human neurons. We also studied interactions of nuclear proteins with MMP‑9‑1562C/T polymorphism by EMSA (Electrophoretic Mobility Shift Assay). We found that nucleoprotein complexes form in an allele‑specific manner in human neurons. Using magnetic beads coated with the human allele C or T, we pulled down nuclear proteins binding specifically to the alleles. Then, we analyzed the identity of these proteins using mass spectrometry. CONCLUSIONS: As a result, we identified numerous transcriptional regulators and co-regulators that may be involved in the allele‑specific modulation of MMP‑9 expression in human neurons.
Effect of auxins: (NAA, IAA), cytokinin BAP and culture conditions (light, darkness) on callus induction in cotyledons of tomato cultivar ‘Maskotka’ and the wild form of Lycopersicon peruvianum was investigated. Callus was obtained in all experimental combinations, except of the culture with L. peruvianum on the medium with 1.0 mg⋅dm⁻³ of IAA. Callus weight, colour and structure depended on the tomato genotypes and experimental conditions. Best medium for the culture of tomato cultivar ‘Maskotka’ and the wild form L. peruvianum proved to be MS medium supplemented with 2.0 mg⋅dm⁻³ of IAA and 1.0mg⋅dm⁻³ of BAP.