Transcriptome Analysis of the Desert Locust Central Nervous System: Production and Annotation of a Schistocerca gregaria EST Database

) displays a fascinating type of phenotypic plasticity, designated as ‘phase polyphenism’. Depending on environmental conditions, one genome can be translated into two highly divergent phenotypes, termed the solitarious and gregarious (swarming) phase. Although many of the underlying molecular events remain elusive, the central nervous system (CNS) is expected to play a crucial role in the phase transition process. Locusts have also proven to be interesting model organisms in a physiological and neurobiological research context. However, molecular studies in locusts are hampered by the fact that genome/transcriptome sequence information available for this branch of insects is still limited. EST information is highly complementary to the existing orthopteran transcriptomic data. Since many novel transcripts encode neuronal signaling and signal transduction components, this paper includes an overview of these sequences. Furthermore, several transcripts being differentially represented in solitarious and gregarious locusts were retrieved from this EST database. The findings highlight the involvement of the CNS in the phase transition process and indicate that this novel annotated database may also add to the emerging knowledge of concomitant neuronal signaling and neuroplasticity events. EST data constitute an important new source of information that will be instrumental in further unraveling the molecular principles of phase polyphenism, in further establishing locusts as valuable research model organisms and in molecular evolutionary and comparative entomology

The expression of tissue-type plasminogen activator, matrix metalloproteases and endogenous inhibitors in the central nervous system in multiple sclerosis: comparison of stages in lesion evolution

The expression of tissue-type plasminogen activator (t-PA) and a number of metalloproteases as well as plasminogen activator inhibitor-1 (PAI-I) and tissue inhibitor of metalloproteases-1 (TIMP-1) was analyzed in the central nervous system (CNS) of normal control and multiple sclerosis (MS) cases by immunohistopathology. The expression of t-PA was detectable only in the blood vessel matrix in control white matter, but positive infiltrating mononuclear cells were also observed in MS white matter and primary lesions. In active plaques this pattern converted to strong positivity of foamy macrophages in areas of demyelination, declining in chronic lesions. In general PAI-1 expression paralleled that of t-PA. Gelatinase A and B were detected predominantly in astrocytes and microglia throughout normal control white matter, with additional positive mononuclear cells in perivascular cuffs in MS white matter. In the demyelinating lesion there is widespread prominent expression of gelatinase B in reactive astrocytes and macrophages, which persists in astrocytes in the chronic lesion. TIMP-1 was also present in the vessel matrix and in lesional macrophages. These observations on the coexpression of enzymes and inhibitors of the matrix degrading cascade in CNS tissue pinpoint t-PA, a -limiting enzyme, and gelatinase B as therapeutic targets in MS

Presence of myotropic peptides in the male accessory reproductive glands of Locusta migratoria

Methanolic extracts of Locusta male accessory glands, fractionated by reversedphase high-performance liquid chromatography, contain several factors which stimulated the spontaneous contractions of the Locusta oviduct in vitro. The myotropic activity of these factors was destroyed by incubation with pronase but not by boiling, indicating that the compounds are peptides. Myotropic factors were also found in extracts of spermathecae of virgin and mated females as well as spermatophores. Comparison of their chromatographic behaviour suggests that at least some of the myotropic factors found in the genital tract of mated females originate from the males. Injection of the gland extracts did not significantly accelerate oviposition. The glands of males treated with precocene I (chemical allatectomy), although very much underdeveloped, contained an increased amount of myotropic factors. The possible function of these myotropic factors in the male accessory glands is discussed. © 1990.status: publishe

Localization of Lom-AG-myotropin I-like substances in the male reproductive and nervous tissue of the locust, Locusta migratoria

Lom-AG myotropin I (Lom-AG-MTI) was the first peptide to be isolated from the male accessory reproductive glands of the locust, Locust migratoria. It shows no sequence similarity to any of the peptides identified from vertebrate or invertebrate tissues. A polyclonal antiserum was used to localize Lom-AG-MTI-like material in the male reproductive system and nervous system of the locust. Immunoreactivity was found in two of the hyaline gland tubules. In the brain, cell bodies were detected in the proto- and deuterocerebrum as well as the frontal ganglion. Nerve fibers were stained in the neuropils of the brain and throughout the labial nerves into the recurrent nerve. Thoracic and last abdominal ganglia contained neurons which could be stained with Lom-AG-MTI antiserum. The pronounced reactivity in the central nervous system suggests a possible neuroregulatory function of the peptide.status: publishe

Isolation, identification and synthesis of Lom-AG-myotropin II, a novel peptide in the male accessory reproductive glands of Locusta migratoria

The male accessory glands of Locusta contain factors which stimulate oviduct contraction. From an extract of 4400 gland masses, a myotropic peptide (Lom-AG-myotropin II) was isolated by HPLC. Sequencing revealed the following sequence: Ala-His-Arg-Phe-Ala-Ala-Glu-Asp-Phe-Gly-Ala-Leu-Asp-Thr-Ala. Chemical synthesis confirmed that this peptide is active in the acid form instead of the amide form as other presently known myotropic peptides. The sequence does not resemble that of any peptide isolated from Locusta or other insects. The myotropin is active on the oviduct of Locusta migratoria but not on the oviduct of Leucophaea maderae. The myotropic activity can be detected on the hindgut of both insects but at much higher peptide concentrations.status: publishe

Isolation, identification and synthesis of PDVDHVFLRFamide (Schisto FLRFamide) in Locusta migratoria and its association with the male accessory glands, the salivary glands, the heart and the oviduct

An amidated decapeptide, exhibiting strong inhibitory activity of spontaneous visceral muscle movements, was isolated from 9000 brain-corpora cardiaca-corpora allata-subesophageal ganglion complexes of the migratory locust, Locusta migratoria. During the process of HPLC purifications, the biological activity of the fractions was monitored using the isolated hindgut of the cockroach Leucophaea maderae. The primary structure of this myotropic peptide is Pro-Asp-Val-Asp-His-Val-Phe-Leu-Arg-Phe-NH2 and is identical to SchistoFLRFamide isolated from the grasshopper, Schistocerca gregaria. It shares the carboxy-terminal sequence FLRFamide with several identified peptides from different phyla. At this moment, six decapeptides isolated from different insect species are identical at 7 of the 10 amino acid residues (X-D-V-X-H-X-FLRFamide). The cockroach, fly, and locust peptides differ only by the N-terminal amino acid residue. Synthetic SchistoFLRFamide showed biological as well as chemical characteristics indistinguishable from the native peptide. It provoked a decrease in frequency and amplitude of contractions of the locust oviduct. By means of a polyclonal antiserum directed against the carboxy terminal of SchistoFLRFamide, we demonstrated that the male accessory glands, the heart, the oviduct, and the salivary glands were innervated by axons containing SchistoFLRFamide-like immunoreactivity. Administration of SchistoFLRFamide elicited an immediate effect on the basal membrane potential of the opalescent tubule gland cells.status: publishe