Mapping of neuropeptide Y expression in Octopus brains

Neuropeptide Y (NPY) is an evolutionarily conserved neurosecretory molecule implicated in a diverse complement of functions across taxa and in regulating feeding behavior and reproductive maturation in Octopus. However, little is known about the precise molecular circuitry of NPY-mediated behaviors and physiological processes, which likely involve a complex interaction of multiple signal molecules in specific brain regions. Here, we examined the expression of NPY throughout the Octopus central nervous system. The sequence analysis of Octopus NPY precursor confirmed the presence of both, signal peptide and putative active peptides, which are highly conserved across bilaterians. In situ hybridization revealed distinct expression of NPY in specialized compartments, including potential “integration centers,” where visual, tactile, and other behavioral circuitries converge. These centers integrating separate circuits may maintain and modulate learning and memory or other behaviors not yet attributed to NPY-dependent modulation in Octopus. Extrasomatic localization of NPY mRNA in the neurites of specific neuron populations in the brain suggests a potential demand for immediate translation at synapses and a crucial temporal role for NPY in these cell populations. We also documented the presence of NPY mRNA in a small cell population in the olfactory lobe, which is a component of the Octopus feeding and reproductive control centers. However, the molecular mapping of NPY expression only partially overlapped with that produced by immunohistochemistry in previous studies. Our study provides a precise molecular map of NPY mRNA expression that can be used to design and test future hypotheses about molecular signaling in various Octopus behaviors.     

The dark-colour-inducing neurohormone of locusts in relation to an albino mutant of Schistocerca gregaria

In the albino mutant of an Okinawa strain of Locusta migratoria (L.) (Orthoptera: Acrididae), albinism is caused by the absence of the dark‐colour‐inducing neurohormone (DCIN), which is present in the corpora cardiaca (CC) of normally coloured phenotypes. This study tests whether the absence of DCIN is responsible for albinism in an albino mutant of another locust, Schistocerca gregaria (Forsk.) (Orthoptera: Acrididae). This seemed feasible because a single Mendelian unit controls albinism in both species. However, implantation of CC, or injection of an extract of CC, from albino donors of S. gregaria, induce dark coloration in crowded nymph recipients of the Okinawa albino mutant of L. migratoria, as effectively as do implanted CC, or injections of extract of CC, from normal phenotype donors of S. gregaria. Therefore, DCIN is present in the albino mutant of S. gregaria, and consequently, the albinism in this mutant is not caused by its absence. Implantation of CC, or injection of extracts of CC, from albino donors of S. gregaria to conspecific albino nymphs does not induce darkening. Only extremely high doses of synthetic DCIN injected into albino nymphs of S. gregaria are effective, inducing some darkening. The dose to induce such darkening in albino nymphs of S. gregaria is 50 nmol, ≈ 5 × 10⁶ times higher than that (10 femtomol) needed to induce equivalent darkening in nymphs of the Okinawa albinos of L. migratoria. The results are discussed and some possible explanations of the observed effects outlined.     

Fungal rhodopsins and opsin-related proteins: eukaryotic homologues of bacteriorhodopsin with unknown functions.

In the last decade, several genome sequencing projects revealed the existence of previously unknown photoreceptors. Among those are eukaryotic rhodopsins of haloarchaeal type, mostly represented by fungal sequences. We have classified and analyzed seventy-seven of these fungal proteins, which show a high similarity of their putative transmembrane regions to those of bacteriorhodopsin. Those sequences can be divided into the two subgroups, fungal rhodopsins (RDs) and opsin-related proteins (ORPs), the latter lacking the lysine residue necessary for retinal binding. We have analyzed the conservation pattern of the residues known to have functional or structural importance in bacteriorhodopsin and discussed dramatic differences in the conservation between RDs and ORPs. We found many cases of multiple forms of RDs and/or ORPs and examined possible reasons for such multiplicity. For some species the reason may lie in functional photobiological diversification, while for the others it follows the pattern of evolutionary recent genome duplication and possible functional redundancy.     

Neurotrophic control of the transmembrane Cl− pump in mammalian muscle fibers

Resting membrane potential of both innervated and denervated rat diaphragm muscle fibers was investigated when the concentration of potential-producing ions was changed in the external fluid and following treatment with furosemide. It was found that equilibrium potential ( ) equalled resting potential level in innervated muscle for Cl^–, but shifts to more positive values compared with resting membrane potential following section of the nerve. Furosemide retards development of post-denervation depolarization of the muscle membrane. It is deduced that trophic influences originating from the motor nerve activates the furosemide-sensitive Cl^– influx system, leading to raised intracellular concentration of Cl^–, a shift in (E_Cl) and depolarization of the muscle membrane.S. V. Kurashov Medical Institute, Minsitry of Health of the RSFSR, Kazan'. Translated from Neirofiziologiya, Vol. 19, No. 6, pp. 766–771, November–December, 1987.     

The ATP/ADP-antiporter is involved in the uncoupling effect of fatty acids on mitochondria

The ATP/ADP-antiporter inhibitors and the substrate ADP suppress the uncoupling effect induced by low (10-20 microM) concentrations of palmitate in mitochondria from skeletal muscle and liver. The inhibitors and ADP are found to (a) inhibit the palmitate-stimulated respiration in the controlled state and (b) increase the membrane potential lowered by palmitate. The degree of efficiency decreases in the order: carboxyatractylate (CAtr) greater than ADP greater than bongkrekic acid, atractylate. GDP is ineffective, Mg.ADP is of much smaller effect, whereas ATP is effective at much higher concentration than is ADP. Inhibitor concentrations, which maximally suppress the palmitate-stimulated respiration, correspond to those needed for arresting the state 3 respiration. The extent of the CAtr-sensitive stimulation of respiration by palmitate has been found to decrease with an increase in palmitate concentration. Stimulation of the controlled respiration by p-trifluoromethoxycarbonylcyanide phenylhydrozone (FCCP) and gramicidin D at any concentrations of these uncouplers is CAtr-insensitive, whereas that caused by a low concentrations of 2,4-dinitrophenol and dodecyl sulfate is inhibited by CAtr. The above effect of palmitate develops immediately after addition of the fatty acid. It is resistant to EGTA as well as to inhibitors of phospholipase (nupercain) and of lipid peroxidation (ionol). Moreover, palmitate accelerates spontaneous release of the respiratory control, developing in rat liver mitochondria under certain conditions. This effect takes several minutes, being sensitive to EGTA, nupercain and ionol. Like the fast uncoupling, this slow effect is inhibited by ADP but CAtr and atractylate are stimulatory rather than inhibitory. In artificial planar phospholipid membrane, palmitate does not increase the membrane conductance, FCCP increases it strongly and dinitrophenol only slightly. In cytochrome oxidase proteoliposomes, FCCP, gramicidin and dinitrophenol (less effectively) lower, whereas palmitate enhances the cytochrome-oxidase-generated membrane potential. In this system, monensin substitutes for palmitate. It is concluded that the ATP/ADP antiporter is somehow involved in the uncoupling effect caused by low concentrations of palmitate and, partially, of dinitrophenol, whereas uncoupling produced by FCCP and gramicidin is due to their action on the phospholipid part of the mitochondrial membrane. A possible mechanism of this effect is discussed.     

Synthesis and properties of DNA duplexes containing hydrocarbon bridges instead of a nucleoside residue

DNA duplexes 14 bp long containing an EcoRII and MvaI restriction site in which a nucleoside is substituted by 1,3-diaminopropane or 1,3-propanediol residue have been chemically synthesized. Diaminopropane bridge was introduced by the chemical ligation, whereas the oligonucleotide containing propanediol was prepared by automatic solid phase phosphoroamidite method on "Victoria-4M" synthesizer. As CD and UV spectra show, the modification destabilises the duplex by 18-20 degrees C without essential distortion of the double helix, except for increase of the conformational mobility in the modified site.     

A method for determining the toxigenicity of micromycetes]

A method is suggested to determine toxigenicity of microscopic fungi from genera Aspergillus, Penicillium, Fusarium, etc. which contaminate fodder, food products and environment objects. The method is based on the property of micromycetes isolated from fodder, food products and environment objects to produce mycotoxins under optimal conditions of their cultivation on the nutrient media. Their further extraction by the organic solvent, evaporation and emulsification of the extract and its peroral introduction to young female rats cause a disease and death of animals. The suggested method may be used for recognizing and preventing mycotoxicoses of farm animals and poultry.