Preservation of plastic properties of synaptic transmission in long-lasting hippocampal slices under the effects of a peptide analog of piracetam, L-pGlu-D-Ala-NH2

The tetanic stimulation of the Schaffer collaterals (SC) in rat hippocamp slices after 6 hrs in vitro conditions did not produce long-term potentiation (LTP) of the field response amplitude in the CA1 pyramidal cell layer. In contrast, LTP after the late tetanization was well preserved in the slices that were perfused for 20 minutes with 0.5 mkM L-pGlu-D-Ala-NH2 (PGAA) after 4-4.5 hrs in vitro. There were no significant reactivity changes during the perfusion of the slices with this drug concentration. Two other drugs with nootropic activity, piracetam (100 mkM) and gamma-hydroxybutyrate (100 mkM, Na-salt) did not prevent the disappearance of LTP in the late period in vitro, while enhanced the reactivity during perfusion period. The maintenance of the plastic properties of the SC-CA1 synaptic transmission under the influence of PGAA is thought to be the result of some specific interaction of the drug with LTP induction mechanisms. LTP damaged in the late period in vitro might be a new model of memory disturbances and this model can turn out to be useful for the comparative estimation of the effectiveness of the drugs with proposed nootropic activity and for the analysis of the possible mechanisms of their action.     

Sequence and relatedness in other bacteria of the Pseudomonas aeruginosa oprP gene coding for the phosphate-specific porin P

The oprP gene encoding the Pseudomonas aeruginosa phosphate-specific outer membrane porin protein OprP was sequenced. Comparison of the derived amino acid sequence with the known sequences of other bacterial porins demonstrated that OprP could be no better aligned to these porin sequences than it could to the periplasmic phosphate-binding protein PhoS of Escherichia coli. Southern hybridization and restriction mapping of the oprP gene in 37 clinical isolates and the 17 serotype strains of P. aeruginosa revealed that restriction sites in the vicinity of the oprP gene were highly conserved. Several species from the Pseudomonas fluorescens rRNA homology group contained DNA that hybridized to an oprP gene probe.     

Effects of 4-methyluracil and carnosine on healing of skin wounds in rats

In experiments in vivo and in vitro the authors studied antioxidative properties of 4-methyluracil and carnosine, their capacity to inhibit sex and accelerate healing of skin wounds. 4-methyluracil and carnosine discover almost the same capacity to decrease in the tissues of the wound and the blood serum in the formation of various intermediate products of free radical oxidation. Data are given on the study of the dynamics of wound healing after a 5-day treatment with equimolar quantities.     

In vivo study on medullary H(+)-sensitive neurons

Using the micro pressure ejection technique, we examined responses of medullary neurons with nonphasic discharges (164 units) to direct application of acidified mock cerebrospinal fluid (CSF, pH 6.85-7.05) in decerebrated spontaneously breathing cats. We found 16 H(+)-sensitive cells; they were excited promptly on application of approximately 500 pl of acidified mock CSF in the vicinity of the neuron under investigation, whereas they were unaffected by microejection of the control mock CSF (pH 7.25-7.60). Of the 16 H(+)-sensitive cells, 10 units were further found to be excited by transcapillary stimulation of the central chemoreceptors by using a method of intravertebral arterial injection of CO2-saturated saline. The discharges increased in a similar time course to that of ventilatory augmentation. Distributions of these 10 specific H(+)-sensitive cells were found in the vicinity of nucleus tractus solitarii as well as deep in the ventrolateral medulla. The present results suggest a possibility that pH-dependent central chemoreceptors, if any, would be located in two distinct medullary regions described in this study.     

Immunoassay employing surface-enhanced Raman spectroscopy

Surface-enhanced Raman scattering (SERS) was used to measure binding between biomolecules with mutual affinity, including antigen-antibody interactions. The conjugation of nitro groups onto bovine serum albumin enhanced their specific SERS activity 10(4)-fold. A dye, 2-[4'-hydroxyphenylazo]benzoic acid (HABA), with a major absorption at the Raman excitation frequency, demonstrated surface-enhanced resonance Raman scattering (SERRS) when captured from solution by avidin-coated silver films. Individual peak intensities showed a logarithmic relationship to the HABA concentration in solution over the range 10(-8) to 10(-5) M. Another resonance dye, p-dimethylaminoazobenzene (DAB) was covalently attached to an antibody directed against human thyroid stimulating hormone (TSH), without loss of antibody activity. The resultant conjugate was used in a sandwich immunoassay for TSH antigen: silver surfaces coated with anti-TSH antibody captured TSH antigen which in turn captured the DAB-anti-TSH antibody conjugate. A linear relationship was observed between the intensity of the resultant SERRS signals and the TSH antigen concentration over a range of from 4 to 60 microIU/ml. These results demonstrate the potential utility of the SERRS effect as a readout in a one-step, no wash immunoassay system.     

Response of carbonic anhydrase to polyethylene glycol-mediated water stress in wheat

Carbonic anhydrase (CA) activity in wheat leaves changed upon leaf dehydration: it decreased at mild stress (relative water content, RWC, 81 %), but increased at severe water stress (RWC 74 %). Phosphoenopyruvate carboxylase activity was not significantly affected by these stresses. This revised version was published online in June 2006 with corrections to the Cover Date.     

Remarkable genetic diversity detected at river buffalo prolactin receptor (PRLR) gene and association studies with milk fatty acid composition

Prolactin is an anterior pituitary peptide hormone involved in many different endocrine activities and is essential for reproductive performance. This action is mediated by its receptor, the prolactin receptor, encoded by the PRLR gene. In this study, we sequenced and characterized the Mediterranean river buffalo PRLR gene (from exon 3 to 10), and we found remarkable genetic diversity. In particular, we found 24 intronic polymorphisms and 13 exonic SNPs, seven of which were non‐synonymous. Furthermore, the polymorphisms identified in the 3′‐UTR were investigated to establish their possible influence on microRNA binding sites. Considering all the amino acid changes and the observed allelic combinations, it is possible to deduce at least six different translations of the buffalo prolactin receptor and, consequently, the presence at the PRLR gene of at least six alleles. Furthermore, we identified a deletion of a CACTACC heptamer between nucleotides 1102 and 1103 of exon 10 (3′‐UTR), and we developed an allele‐specific PCR to identify the carriers of this genetic marker. Finally, the SNP g.11188A>G, detected in exon 10 and responsible for the amino acid replacement p.His328Arg, was genotyped in 308 Italian Mediterranean river buffaloes, and an association study with milk fat traits was carried out. The statistical analysis showed a tendency that approached significance for the AA genotype with higher contents of odd branched‐chain fatty acids. Thus, our results suggest that the PRLR gene is a good candidate for gene association studies with qualitative traits related to buffalo milk production.