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In order to automate sample preparation processes, a precision pattern dispenser was designed to reproducibly dispense radioactive solutions at pre-defined positions. It is composed of an automatic liquid sample handling unit coupled to an XYZ table. Qualification tests were conducted to evaluate the performance of the instrument and to assess the compliance with the requirements, in particular trueness (< 2%) and repeatability (< 1%). The instrument allows preparing sources in different source holders and on air filters, in a fast and accurate way.

An HPLC analysis of hemolymph extracts was undertaken to uncover differences between desert locusts, Schistocerca gregaria , reared under either crowded or isolated conditions. Some differences in the chromatographic pattern could be detected. One of the major peaks in the hemolymph of crowd-reared adults was found to be a minor one in isolated-reared individuals, whereas other peaks increased after solitarization. The differences became even more pronounced after several generations of isolated rearing. The dominant chromatographic peak in hemolymph extracts of the crowd-reared animals was identified as a novel peptide with a molecular mass of 6080 Da. Edman degradation in combination with enzymatic fragmentation and quadrupole-time of flight (Q-Tof) mass spectrometry revealed the full sequence: DNADEDTICVAADNKFYLYANSLKLYTCYNQLPKVYVVKPKSQCRSSLSDCPTS. This 54 aa-peptide is very abundant in hemolymph of crowd-reared adults. Its concentration in hemolymph amounts to 0.1 mM. To uncover the function, its effects were investigated in several bioassays, so far without positive results. One of the other peaks differentially expressed in the individuals of the two phases was identified as SGPI-2 (MW=3794 Da), which is a serine protease inhibitor in locusts.

The aliphatic amino diacid alpha-aminosuberic acid can function as an effective, stable mimic of the hydrolysis-susceptible Tyr(SO3H) group in sulfakinin neuropeptide analogs for both hindgut contractile activity in cockroach and food intake-inhibition activity in the desert locust. In the analog, the acidic sulfate group is replaced with an acidic carboxyl group. The degree of activity of sulfakinin analogs is correlated with the carboxyl/alpha-carbon distance in the cockroach hindgut contractile assay. The results represent an important step in the design and synthesis of biostable, sulfakinin analogs that could potentially suppress the feeding behavior of destructive insect pests of agricultural importance.

Summary No single fly gonadotropin has as yet been identified with certainty. Dababase analysis fails to yield positive results when the genomic database of Drosophila is scanned for the presence of family members of gonadotropins that have already been identified in other insects. However, a candidate gonadotropic peptide (cAMP generating peptide, Neb-cGP) was purified some time ago from the fleshfly Neobellieria bullata. A short form of this peptide was found to stimulate cAMP production in the ovaries of the fleshfly. In the present study, we gathered additional arguments that suggest a role for Neb-cGP as a gonadotropic hormone. Brains of male and female adult Neobellieria bullata were stained with antiserum directed to the cAMP generating peptide. In both sexes four lateral neurosecretory cells in the dorsal part of each pars lateralis were stained. In addition, mass spectrometric read-outs of extracts of fleshfly corpora cardiaca displayed the full length form (48 amino acid residues) of the cAMP-ge...

The degradation of the unblocked hexapeptide, trypsin modulating oostatic factor of the flesh fly Neobellieria ( Sarcophaga ) bullata (Neb-TMOF) was studied in vitro in the hemolymph of the lepidopteran Spodoptera frugiperda , the orthopteran Schistocerca gregaria and the dictyopteran Leucophaea maderae . The half-life in the different species varied from ∼3 min in L. maderae to ∼25 min in S. gregaria . Purification of the degradation products and ESI-Qq-oa-Tof mass spectrometry revealed the fragments Asn-Pro-Thr-Asn, Leu-His and Asn-Pro, which were the same in the hemolymph of all species. Except in Leucophaea , Neb-TMOF was cleaved in dipeptides starting from the C-terminus and the reaction could be, at least partially, inhibited by captopril. These observations suggest that a dipeptidase, which has very similar enzymatic properties as mammalian angiotensin converting enzyme (ACE) and which circulates in the hemolymph, apparently is involved in the breakdown of Neb-TMOF and might be a common but not a universal enzyme in insect hemolymph. The introduction of Neb-TMOF into the gut of S. gregaria with the help of a capillary tube (intubation) demonstrated that the intact peptide is able to cross the gut epithelium and to appear in the hemolymph compartment. Since [ 3 H ] -inulin, which is too large to cross cell membranes, was found to penetrate the gut walls at a measurable rate, the paracellular pathway might be also permeable to smaller peptides. There was indeed a clear correlation between the molecular weight of inulin, Neb-TMOF, and inositol and the rate of penetration of these compounds through the gut epithelium to the hemolymph. These are promising findings in view of a potential use of such peptides for insect control purposes.