The proenkephalin-A-derivative Met-enkephalin-Arg-Gly-Leu is not present in the feline species

RadAA: A Command-line Tool for Identification of Radical Amino Acid Changes in Multiple Sequence Alignments

High-throughput sequencing has revolutionised biology and medicine. Numerous genomes and transcriptome assemblies are now available, and these genomic data sets lend themselves to comparisons between species, strains, and other strata. Researchers often need to rapidly identify changes, in particular amino acid substitutions that could confer biological function in their system of interest. However, we are not aware of an easy-to-use tool that can be used to detect such changes, and researchers currently rely on idiosyncratic computer code. We present RadAA, a command-line tool which screens multiple sequence alignments for radical amino acid changes in a stratum/strata by classifying residues into groups by charge (with cysteine in its own group). RadAA is easy to use, even for researchers with little experience in computational biology. It can be run on most operating systems - including MacOS, Windows, and Linux - and integrated into high-performance computing environments. The RadAA source code and executable binaries are freely available at https://github.com/sciseim/RadAA.

An immunocytochemical mapping of methionine-enkephalin-Arg6-Gly7-Leu8 in the cat brainstem

The distribution of methionine-enkephalin-Arg6-Gly7-Leu8-immunoreactive cell bodies and fibres was studied in the brainstem of the cat using an indirect immunoperoxidase technique. In the mesencephalon, immunoreactive cell bodies were observed in the periaqueductal grey, the dorsal raphe nucleus, the central and pericentral nuclei of the inferior colliculus and the pericentral division of the dorsal tegmental nucleus. In the pons, immunoreactive cell bodies were observed in the dorsolateral division of the pontine nucleus; below the central division of the dorsal tegmental nucleus; above the dorsolateral division of the pontine nucleus, and close to the superior cerebellar peduncle. In the medulla oblongata, immunoreactive cell bodies were observed in the laminar spinal trigeminal nucleus and in the lateral tegmental field; the dorsal motor nucleus of the vagus; the prepositus hypoglossal nucleus; the medial nucleus of the solitary tract; the rostral division of the cuneate nucleus, and close to the parvocellular division of the alaminar spinal trigeminal nucleus. The highest (moderate) density of immunoreactive fibres was observed in the periaqueductal grey; the parvocellular and magnocellular divisions of the alaminar spinal trigeminal nucleus; the laminar spinal trigeminal nucleus; the rostral division of the cuneate nucleus; the dorsal motor nucleus of the vagus; the lateral nucleus of the solitary tract, and in the midline between the central divisions of the reticulotegmental pontine nucleus. The widespread distribution of methionine-enkephalin-Arg6-Gly7-Leu8 in the cat brainstem indicates that the peptide might be involved in several physiological functions.

Distribution of met-enkephalin immunoreactivity in the diencephalon and the brainstem of the dog

The endogenous opioid system, in particular the enkephalins, has been implicated in a vast array of neurological functions. The dog could be a suitable model for the study of complex interactions between behavioral state and regulatory physiology in which the opioid system appeared to be implicated. Moreover, opiate derivatives are currently used in veterinary clinic and sometimes pharmacologically tested in the dog. However, there are no anatomical data regarding the organization of the opioid system in this species. The present work represents the first attempt to map the distribution of Met(5)-enkephalin-like-immunoreactive (Met-enk-li) cell bodies and fibers in the diencephalon and the brainstem of the dog. In the diencephalon, labeled cells were present in all the mid-line and intralaminar thalamic nuclei; the lateral posterior, pulvinar and suprageniculate nuclei; the ventral nucleus of the lateral geniculate body and the medial geniculate body. Additionally, Met-enk-li cells were seen in every hypothalamic nucleus except in the supraoptic. Variable densities of labeled fibers were also seen in all these nuclei except in the medial geniculate body and in most areas of the lateral posterior and pulvinar nuclei. In the mesencephalon, positive cells were found in the periaqueductal gray, the Edinger-Westphal and interpeduncular nuclei, delimited areas of the superior and inferior colliculi and the ventral tegmental area. In the rhombencephalon, labeled cells were seen in the majority of the nuclei in the latero-dorsal pontine tegmentum, the nuclei of the lateral lemniscus, the trapezoid, vestibular medial, vestibular inferior and cochlear nuclei, the prepositus hypoglossal, the nucleus of the solitary tract and the dorsal motor nucleus of the vagus, the infratrigeminal nucleus and the caudal part of the spinal trigeminal nucleus and in the rhombencephalic reticular formation. The distribution of fibers included additionally the substantia nigra, all the trigeminal nerve nuclei, the facial nucleus and a restricted portion of the inferior olive. These results are discussed with regard to previous reports on the distribution of Met-enk in other species.

Cat proenkephalin-A does not contain the opioid octapeptide

The sequence of a large cDNA fragment of proenkephalin-A from the cat adrenal medulla was obtained using reverse transcription followed by polymerase chain reaction, and cloning. This cDNA encompasses the region normally containing all the opioid peptides, except the C-terminal heptapeptide. As with other species, cat proenkephalin-A contains four conserved copies of (Met5)-enkephalin, and one of (Leu5)-enkephalin, flanked by processing sites of paired basic amino acids. However, significant differences were found in the nucleotide and deduced amino acid sequences in the region of the octapeptide. In particular, the essential tyrosyl residue is substituted by a histidyl residue, making it unlikely that the cat equivalent would have opioid activity. Furthermore, the peptide is not flanked by paired basic residues, suggesting it is not processed.

Distribution of enkephalin immunoreactivity in sympathetic prevertebral ganglia and digestive tract of guinea-pigs and rats

The aim of the present study was to determine the distribution of methionine-enkephalin (ME) and leucine-enkephalin (LE) immunoreactivity in the sympathetic prevertebral ganglia (coeliac plexus and inferior mesenteric ganglion) and in the myenteric plexus-muscular layer complex of the digestive tract in guinea-pigs and rats. This study was performed using the same immunological approaches including radioimmunoassays and HPLC characterization as those used previously on cats in order to be able to make inter-region and inter-species comparisons. In rat and guinea-pig prevertebral ganglia, the distributions of the enkephalin immunoreactivities were comparable and were characterized by a low ME/LE concentration ratio, of less than 1. In the digestive tract of rats, the enkephalin immunoreactivities were homogeneously distributed, whereas in guinea-pigs, they were found to be very low in the lower oesophageal sphincter and high in the duodenum. In both species, the ME/LE concentration ratio was around 2. The ME/LE concentration ratio determined in the present study in peripheral nervous structures was much lower than that determined previously in the rat brain. Radioimmunoassay and biochemical data might indicate that different mechanisms are responsible for the processing and/or degradation of enkephalins in the central and peripheral nervous systems. The present study provides further evidences that there are tissue- and species-dependent differences in the distribution of enkephalin immunoreactivities. These differences should be taken into consideration when dealing with the effects and the role of enkephalins in the nervous control of intestinal motility in mammals.