Two Peptidergic Drugs Increase the Synaptophysin Immunoreactivity in Brains of 24-month-old Rats

The brain-derived peptidergic drug Cerebrolysin has been found to support the survival of neurones in vitro and in vivo. Positive effects on learning and memory have been demonstrated in various animal models and also in clinical trails. In the present study, the effects of Cerebrolysin and its peptide preparation E021 on the synapse density in the hippocampus, the dentate gyrus and in the entorhinal cortex of 24-month-old rats were investigated. Rats received the drugs or saline for control for 19 consecutive days (2.5ml/kg per day). Slices of the brains were immunohistochemically stained with anti-synaptophysin, which is a specific marker of presynaptic terminals. Quantification of the synapse density was done by using light microscopy and a computerised image analysing system. Our results clearly showed that the rats benefit from the administration of both drugs, showing an enhancement in the number of synaptophysin-immunostained presynaptic terminals in the entorhinal cortex, the dentate gyrus, and also in the hippocampal subfields CA1, CA2, CA3 stratum lucidum and CA3 stratum radiatum. It can be assumed that these effects are the reason for improved cognitive performances of rats treated with Cerebrolysin and E021.     

Peptide binding to intestinal epithelium: distinct sites for insulin, EGF and VIP

Several peptides, including insulin, epidermal growth factor and vasoactive intestinal polypeptide bind to intestinal epithelial cells. However, it is unclear whether one binding site binds several peptides or whether separate sites exist for each peptide. These studies were designed to examine the specificity of peptide binding sites on intestinal epithelial cells. Peptide binding was measured directly with [125I]radiolabelled peptides to isolated enterocytes prepared from rabbit ileum. The characteristics of insulin and epidermal growth factor binding were similar. Both insulin and epidermal growth factor specific binding was saturable, directly correlated to cell concentration and temperature and pH dependent. The total number of insulin binding sites per cell was 4500, that for epidermal growth factor was 2280. Scatchard analysis for both peptides produced curvilinear plots. Dissociation of both peptides from the binding site was increased in the presence of their respective unlabelled peptide. However, insulin specific binding was not altered by epidermal growth factor, and epidermal growth factor specific binding was unaffected by insulin. Further, both insulin and epidermal growth factor failed to inhibit the specific binding of vasoactive intestinal polypeptide to ileal enterocytes, and vasoactive intestinal polypeptide did not inhibit insulin or epidermal growth factor specific binding. These studies demonstrate that insulin, epidermal growth factor and vasoactive intestinal polypeptide interact with three distinct membrane binding sites on the enterocyte.     

Increased density of glutamate receptor subunit 1 due to Cerebrolysin treatment: an immunohistochemical study on aged rats

Glutamate receptor subunit 1 (GluR1) is one of the four possible subunits of the AMPA-type glutamate receptor. The integrity of this receptor is crucial for learning processes. However, reductions of GluR1 are noticeable in the hippocampal formation of patients suffering from Alzheimer's disease. Such degradations presumably result in an impaired synaptic communication and might be causally linked to the neurodegenerative process in this cognitive disorder. The peptidergic drug Cerebrolysin counteracts cognitive deficits of patients affected by Alzheimer's disease. These findings are supported by experiments revealing neuroprotective and neurotrophic capacities of the drug. In order to examine the effect of the drug on the density of GluR1 in hippocampal formation 24-month-old rats were treated with either Cerebrolysin or its peptide fraction E021, or saline as a control. Spatial navigation of the animals was tested in the Morris water maze. Rat brain slices were stained immunohistochemically with a GluR1-specific antibody. GluR1 immunoreactivity was quantified using light microscopy and a computerised image analysis system. Cerebrolysin and E021 increased GluR1 density in most measured regions of the hippocampal formation in a highly significant way. These results correlate with the behavioural outcome, revealing an improvement in learning and memory of these rats after treatment with Cerebrolysin and E021.     

Molecular basis of seed lipoxygenase null traits in soybean line OX948

The poor stability and off-flavors of soybean oil and protein products can be reduced by eliminating lipoxygenases from soybean seed. Mature seeds of OX948, a lipoxygenase triple null mutant line, do not contain lipoxygenase proteins. The objective of this study was to determine the molecular basis of the seed lipoxygenase null traits in OX948. Comparisons of the sequences for lipoxygenase 1 (Lx1) and lipoxygenase 2 (Lx2) genes in the mutant (OX948) with those in a line with normal lipoxygenase levels (RG10) showed that the mutations in these genes affected a highly conserved group of six histidines necessary for enzymatic activity. The OX948 mutation in Lx1 is a 74?bp deletion in exon 8, which introduces a stop codon that prematurely terminates translation. A single T?CA substitution in Lx2 changes histidine H532 (one of the iron-binding ligands essential for L-2 activity) to glutamine. The mutation in the lipoxygenase 3 (Lx3) gene in OX948 is in the promoter region and represents two single base substitutions in a cis-acting AAATAC paired box. All three mutations would result in the loss of lipoxygenase activity in mature seed. The seed lipoxygenase gene mutation-based molecular markers could be used to accelerate and simplify breeding efforts for soybean cultivars with improved flavor.     

Seed and agronomic QTL in low linolenic acid, lipoxygenase-free soybean (Glycine max (L.) Merrill) germplasm.

Linolenic acid and seed lipoxygenases are associated with off flavours in soybean products. F5 recombinant inbred lines (RILs) from a cross between a low linolenic acid line (RG10) and a seed lipoxygenase-free line (OX948) were genotyped for simple sequence repeats (SSR), random amplified polymorphic DNA (RAPD), sequence-tagged sites (STS), and cleaved amplified polymorphic sequence (CAPS) markers and evaluated for seed and agronomic traits at 3 Ontario locations in 2 years. One hundred twenty markers covering 1247.5 cM were mapped to 18 linkage groups (LGs) in the soybean composite genetic map. Seed lipoxygenases L-1 and L-2 mapped as single major genes to the same location on LG G13-F. L-3 mapped to LG G11-E. This is the first report of a map position for L-3. A major quantitative trait locus (QTL) associated with reduced linolenic acid content was identified on LG G3-B2. QTLs for 12 additional seed and agronomic traits were detected. Linolenic acid content, linoleic acid content, yield, seed mass, protein content, and plant height QTL were present in at least 4 of 6 environments. Three to 8 QTLs per trait were detected that accounted for up to 78% of total variation. Linolenic acid and lipoxygenase loci did not overlap yield QTL, suggesting that it should be possible to develop high-yielding lines resistant to oxidative degradation by marker-assisted selection (MAS).