Changes in excitability in the motor cortex of the dog during switching-over conditioned escape and avoidance reflexes

Excitability of the motor cortex (projection of the foreleg), judged by the threshold of flexion reaction to its stimulation during elaboration of conditioned transswitching (CT), was studied in dogs. CT was elaborated for instrumental reflexes of escape (1-st CT variant) and avoidance (2-nd CT variant). In the 1-st variant the dog escaped from the hydrochloric acid solution, if during its administration it produced an active flexion of the foreleg in situation A and an active extension of the same leg in situation B, with a permanent action of a switch (a fan). In the 2-nd CT variant, the dog avoided the acid, if in situation A, in response to a tone of 250 Hz, it actively lifted its foreleg, and if in situation B, it actively resisted a passive lift in response to the same stimulus. In escape CT as well as in avoidance CT, there was a statistically significant difference between the thresholds of flexion reaction. The threshold was lower in situation of instrumental flexion reflex formation in comparison to the situation of extension reflex formation.     

Eukaryotic polypeptide chain release factor eRF3 is an eRF1- and ribosome-dependent guanosine triphosphatase.

Termination of translation in eukaryotes is governed by two polypeptide chain release factors, eRF1 and eRF3 on the ribosome. eRF1 promotes stop-codon-dependent hydrolysis of peptidyl-tRNA, and eRF3 interacts with eRF1 and stimulates eRF1 activity in the presence of GTP. Here, we have demonstrated that eRF3 is a GTP-binding protein endowed with a negligible, if any, intrinsic GTPase activity that is profoundly stimulated by the joint action of eRF1 and the ribosome. Separately, neither eRF1 nor the ribosome display this effect. Thus, eRF3 functions as a GTPase in the quaternary complex with ribosome, eRF1, and GTP. From the in vitro uncoupling of the peptidyl-tRNA and GTP hydrolyses achieved in this work, we conclude that in ribosomes both hydrolytic reactions are mediated by the formation of the ternary eRF1-eRF3-GTP complex. eRF1 and the ribosome form a composite GTPase-activating protein (GAP) as described for other G proteins. A dual role for the revealed GTPase complex is proposed: in " GTP state," it controls the positioning of eRF1 toward stop codon and peptidyl-tRNA, whereas in "GDP state," it promotes release of eRFs from the ribosome. The initiation, elongation, and termination steps of protein synthesis seem to be similar with respect to GTPase cycles.     

Detoxification of ochratoxin A,a food contaminant: Prevention of growth of Aspergillus ochraceus and its production of ochratoxin A

The toxicity of ochratoxin A (OTA), a mycotoxin produced by fungi ofAspergillus orPenicillium genera is now well documented. Its nephrotoxicity, immunosuppression, teratogenicity, and carcinogenicity have been widely studied. Physical and biochemical methods have been studied to prevent these toxinogenicAspergillus andPenicillium from producing OTA, and/or to destroy the mycotoxin when already produced in a liquid or a solid medium. Repeated freezing at ? 20?C and thawing at + 26?C aleatory reduce OTA production in a liquid medium. Exposure to UV B for different periods of time is efficient in preventing OTA production in a liquid medium. Gamma-irradiation from 2 to 5 kGy gives good results in preventing the production of OTA or destroying it when already produced. Carboxypeptidase is very efficient at 5 units/50 ml in a liquid medium for cleaving the OTA already produced.     

Genomic and proteomic profiles of <Emphasis Type="Italic">Acholeplasma laidlawii</Emphasis> strains differing in sensitivity to ciprofloxacin

As a result of comparative analysis of complete genomes as well as cell and vesicular proteomes of A. laidlawii strains differing in sensitivity to ciprofloxacin, it was first shown that the mycoplasma resistance to the antibiotic is associated with the reorganization of genomic and proteomic profiles, which concerns many genes and proteins involved in fundamental cellular processes and realization of bacterial virulence.     

The role of fish-poultry integration on fish growth performance,yields and economic benefits among smallholder farmers in sub-Saharan Africa,Tanzania

Aquaculture practices from sub-Saharan Africa are characterised by low production, owing to improper technology. Production can be increased through integrating fish farming with other existing on-farm activities, particularly livestock husbandry. We assessed the role of fish-poultry integration on all male Nile tilapia, Oreochromis niloticus growth performance, yields and economic benefits among smallholder farmers in sub-Saharan Africa, Tanzania. The study also compared phytoplankton species composition, abundance and biomass between the fish-poultry integration and non-integrated system. After 180 days of the experiment, all male O. niloticus cultured under fish-poultry integration exhibited significantly higher growth rates than those in the non-integrated system (p < 0.05). Gross fish yield (GFY), net fish yield (NFY) and net annual yields (NAY) obtained from fish-poultry integration were significantly higher than those from non-integrated system (p < 0.05). Partial enterprise budget analysis revealed that fish-poultry integration was more profitable than the non-integrated system. Moreover, fish-poultry integrated system produced significantly higher phytoplankton abundance and biomass than those from the non-integrated system. Results demonstrate that rural smallholder farmers can achieve higher growth rate, farm net yields and income by integrating all male O. niloticus with other on-farm activities than practising a stand-alone fish culture system.     

Synthesis of Random DNA Libraries for In Vitro Selection and Analysis of Their Nucleotide Composition

Russian Journal of Bioorganic Chemistry - Aptamers are DNA or RNA molecules that specifically bind certain targets with high affinity due to the formation of unique spatial structures. Aptamers...     

Efficiency of polysaccharide translam for early treatment of acute radiation illness

Antiradiation therapeutic efficiency of translam (1-->3; 1-->6-beta-D-glucan) produced by enzymatic synthesis out of laminarin, polysaccharide of Laminaria cychorioides, has been studied in four animal species (mice, guinea-pigs, dogs, monkeys). A stable curative effect has been observed following its administration within first 24 h after radiation exposure at doses that cause acute radiation sickness (about LD90). The preparation is nontoxic and has a broad therapeutic range which permits its practical application.