Learning in the intact cockroach (Periplaneta americana) when placed in a punishment situation.

Examined whether 40 intact cockroaches, Periplaneta americana, in a yoked-control punishment paradigm exhibit escape or avoidance learning, or both. Evidence for avoidance learning was unequivocal. Escape learning was not found. Asymptotic avoidance learning was found by 1.5 min. of training. The advantages of defining learning by experimental-control differences developing during training are discussed. (15 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Fine structure of the first optic ganglion (lamina) of the cockroach, Periplaneta americana

The stuctural organization of the first optic ganglion (lamina) of the cockroach (Periplaneta americana) was investigated by the use of light and electron microscopy. Each compound eye of the cockroach is composed of up to 2000 visual units (ommatidia) of the fused rhabdom type. The ommatidia themselves consist of eight receptor cells which terminate as axons in either the first or second optic ganglion. Three different short visual fibre types end in two separate strata in the lamina, and one long fibre type ends in the second optic ganglion. Monopolar second-order neurons with wide field branching patterns in the middle stratum of the first synaptic region have postsynaptic contacts with sort visual fibres. Horizontal fibre elements with branching patterns at different levels of the lamina apparently from three horizontal plexuses with presynaptic and/or postsynaptic connections to first-and second-order neurons. The lack of well-organized fibre cartridges containing a constant number of first and second order neurons in each fascicle and the presence of only unistratified wide field monopolar cells could represent, as compared to other insect orders, a primitive stage in the development of the first optic ganglion.     

Stress-induced release of octopamine in the American cockroach Periplaneta americana L

The level of arachidonic acid (AA) metabolites in the supernatants of cultured peritoneal exudate cells (PEC) were studied under various conditions using BCG and Corynebacterium parvum as stimulators. The metabolite levels were analyzed by thin layer chromatography (TLC). The degree of macrophage cytotoxic/cytostatic activity was dependent on the dose and character of stimulators used and the source of macrophages. The application of microcytotoxicity assay for the evaluation of tumor cell lysis (lung sarcoma SaL-1) in vitro revealed that peritoneal macrophages from healthy and tumor bearing BALB/c mice may affect the degree of antitumor response. In the supernatants of cultured PEC from tumor bearing mice AA level increased (by 10-fold) in comparison with PEC from healthy mice. Stimulation with BCG induced over a double level of AA in PEC isolated from tumor bearing mice nonstimulated or stimulated with C. parvum. A lower level of prostaglandins (PGs) was found in the supernatants of cultured PEC isolated from healthy mice (stimulated and non-stimulated), but the highest level of PGs was observed in the supernatants of cultured PEC isolated from tumor bearing mice stimulated with BCG. The unique metabolite of AA was found only in the supernatants from nonstimulated PEC from tumor bearing mice. PEC from tumor bearing mice produced metabolites of AA which were not detected in control group. These results suggest that macrophages also play a regulatory role by secretion of AA. This process can be modified by bacterial antigens.     

Isolation of a novel RFamide peptide from the midgut of the American cockroach, Periplaneta americana

In insects (FM)RFamide-immunoreactive endocrine cells are ubiquitously present in the midgut, but the identity of the peptide(s) produced by these cells is unknown. The major RFamide-immunoreactive peptide from the midgut of the American cockroach, Periplaneta americana, was isolated and identified as Ala-Asn-Arg-Ser-Leu-Arg-Leu-Arg-Pheamide. This is a novel member of an arthropod peptide family, previously known only from mosquitoes and horseshoe crabs. Its abundance in the midgut suggests that it plays an important function in digestion.     

Incubation effect in the cockroach (Periplaneta Americana).

Recorded in Exp I the activity of 72 cockroaches in an open field in which they had received footshock (FS) 1, 3, 10, 30, or 120 min before. The FS produced an incubation effect, i.e., a general decrease in activity, with the greatest decrease occurring at the longer intervals. In Exp II, activity of 77 cockroaches was recorded in an open field 120 min after 1 FS and 1, 3, 10, or 30 min after a 2nd. When no 2nd FS was administered, the cockroaches were inactive; however, when testing occurred within 10 min of the 2nd FS, activity was greatly increased. This gradient of hyperactivity paralleled exactly the incubation effect demonstrated in Exp I. Results of both experiments are almost identical to the results of comparable experiments in which rats have served as Ss. Thus, the incubation effect is an adaptive behavior pattern resulting from the transient activating effects of noxious stimulation. (29 ref.) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Locations and central projections of neurons associated with the retrocerebral neuroendocrine complex of the cockroach Periplaneta americana (L.)

Retrograde diffusion and precipitation of Co2+ reveals in the ipsilateral pars lateralis (PL) and contralateral pars intercerebralis (PI) of the brain neurons that enter the corpus cardiacum (CC), and, possibly, the corpus allatum (CA) on each side. The PL group consists of 29.6 +/- 8.4 somata that fill. Of these, 5.6 +/- 0.6 exceed 25 micrometer in diameter, 14.3 +/- 2.7 range from 15--25 micrometer, and 9.6 +/- 7.6 are smaller than 15 micrometer. After CoCl2 was applied to the right CC-CA of two males, 239 and 265 somata in the left PI stained. Except for 16 ranging from 30--45 micrometers and chiefly located anteriorly, a majority of these somata measured 10--25 micrometer. The only somata revealed by staining whole brains with the performic acid-resorcin fuchsin method are neurosecretory cells 10--20 micrometer in diameter located within the PI. In starved adult males there are 92.4 +/- 8.1 on the right, and 93.2 +/- 6.9 on the left. The largest somata in the PL group contain numerous granules that stain with paraldehyde fuchsin. These somata also fill with Co2+, and belong to neurosecretory cells that extend into the CC-CA. The cerebral distribution of branches from the PL group, and the relationship of these to the corpora pedunculata, central body, and arborizations from the PI decussation are described.     

Influence of the subesophageal ganglion on the electrical activity of neurons of the metathoracic ganglion of the cockroach Periplaneta americana

Studies have been made of non-specific effect of suboesophageal gnaglion on excitability of the segmental centers in the cockroach P. americana. It was shown that the electrical stimulation of the ganglion increases the frequency of the spontaneous activity and decreases the threshold of the evoked reactions in neurons of the metathoracic ganglion. The level of activation depends on the intensity of stimulation. Application of GABA (0.1 M) to the suboesophageal ganglion decreases the frequency of the background activity in the segmental neurons, this effect being presumably due to activation of the inhibitory structures. The descending influences from the suboesophageal ganglion may spread to centers of the metathoracic ganglion along monosynaptic pathways.     

Quantitative structure-activity studies of octopaminergic 2-(arylimino)thiazolidines and oxazolidines against the nervous system of Periplaneta americana L

The quantitative structure-activity relationship (QSAR) of octopaminergic 2-(arylimino)thiazolidines (AITs) and 2-(arylimino)oxazolidines (AIOs) against the thoracic nerve cord of the American cockroach, Periplaneta americana L., was analysed using reported physicochemical parameters and regression analysis. The more electron-donating, the less bulky at m-position, and the more hydrophobic the substituent, the greater the activity. The plots of observed log Vmax values against calculated log Vmax values having substituents on the m-position deviated downwards from those of compounds having substituents at the 0- and/or p-positions. The more hydrophobic and the more electron-withdrawing the substituent, the greater the activity. AIO with a 2, 3, 4-trichlorophenyl group (58) was more active than its thiazolidine derivative, 2-(2,3,4-trichlorophenylimino)thiazolidine (38) in terms of Vmax:Vmax of 58 was 30% relative to octopamine (OA), whereas that of 38 has been 9% relative to OA, respectively. Superimposition of energy-minimized OA and 58 revealed structural and conformational similarities that might account for the high activity of 58.     

Effect of diflubenzuron on the incorporation of UDP-N-acetyl-[3H]glucosamine (UDP-[3H]NAGA) to chitin in permeabilized, and isolated integuments from the newly molted American cockroach Periplaneta americana

1. Diflubenzuron (DFB) was found to inhibit the incorporation of UDP-N-acetyl-[3H]glucosamine (UDP-[3H]NAGA) to chitin in permeabilized and isolated integument from newly molted American cockroach. 2. The favorable experimental conditions demonstrating the effect of diflubenzuron were: 10 mM phosphate, low calcium concentration (10(-6) M-10(-8) M), high potassium concentration (> 100 mM), and high pH (> or = 7). 3. The action of diflubenzuron was completely erased by preincubating the isolated integument with valinomycin, FCCP, or A23187. 4. By lowering the external pH to 5.2, it was also possible to reduce the rate of UDP-[3H]NAGA incorporation to the extent that DFB's effect was no longer recognizable. 5. Both Cs+ and Rb+ could replace K+ in maintaining a high level of chitin synthesis and the inhibitory action of DFB under the optimum conditions.     

Purification and characterization of NADH-dependent glutamate synthase from the silkworm fat body (Bombyx mori)

NADH-dependent glutamate synthase (Nadh-Gogat; EC 1.41.14) was purified 766-fold from the fat body of 5th instar larvae of the silkworm with a final specific activity of 13.8 units/mg protein by a produce including ammonium sulfate fraction, Q-Sepharose HP ion exchange column chromatography, Blue Sepharose FF affinity column chromatography and Superdex 200 HR gel filtration. The purified enzyme yielded a single band corresponding to a molecular mass of 195kDa by SDS-polyacrylamide gel electrophoresis. Molecular mass of the native enzyme was estimated to be 190 kDa by Superdex 200HR gel filtration, suggesting that the enzyme is composed of a monomeric polypeptide. The enzyme showed an absorption spectrum with maximum values at 272, 375, and 435 nm, suggesting the presence of a flavin prosthetic group in the enzyme. The N-terminal amino acid sequence showed a high similarity to those of other GOGATs from plants, yeast and bacteria, but no similarity to other known proteins was detected. The enzyme exhibited a strong specificity to the electron donor and substrates; NADH as electron donor, 2-oxoglutarate as amino acceptor and glutamine as amino donor were essential for the catalytic activity. The optimum pH was around 7.5, at which Km values for 2-oxoglutarate, glutamine and NADH were 17, 220 and 5.7 micro M, respectively. Azaserine, 6-diazo-5-oxonorleucine and p-chloromercuribenzoic acid were strong inhibitors of the activity. These result show that NADH-GOGAT in the silkworm fat body strongly resembles other eukaryotic NADH-GOGATs, suggesting that it plays a significant role in ammonia assimilation in the same manner as the other enzymes.     

Identification of the swine pathogen Serpulina hyodysenteriae in rheas (Rhea americana)

Recently intestinal spirochetes were isolated from rheas in Ohio and Iowa with a necrotizing typhlocolitis. These intestinal spirochetes, strains R1 and NIV-1, were characterized and compared with other intestinal spirochetes, including strains of S. hyodysenteriae. Both rhea spirochetes were indole positive, strongly beta-hemolytic, grew under a 1% O2:99% N2 atmosphere, and were morphologically similar to spirochetes in the genus Serpulina. Analysis of rRNA gene restriction patterns (ribotypes), and immunoblots of whole cell proteins, indicated both spirochetes were similar to Serpulina hyodysenteriae strains from swine. Comparisons of nearly complete sequences (> 1458 bases) of the 16S rRNA gene of the two rhea spirochetes with S. hyodysenteriae strains confirmed that rhea spirochetes R1 and NIV-1 were strains of S. hyodysenteriae. These results indicate that S. hyodysenteriae has a broader host range than previously recognized.     

Fatty acids in 80 brands of edible vegetable oil and in 14 brands of mayonnaise (author's transl)

The fatty acid patterns have been defined in 80 commonly used table oils chosen at random and of 14 brands of mayonnaise commercially available in West Germany. In addition, sterols of the various mayonnaises were analysed. The oils could be grouped into 8 different categories: 12 oliver oils, 8 maize oils, 14 soya oils, 5 linseed oils, 22 sunflower oils, 3 safflower oils, 5 groundnut oils, and 8 rapeseed oils. As a result of the analyses, it is in almost every case a question of a pure variety of non-animal oils. The range of the values obtained for the composition of the fatty acids for each variety, which can be considerable, represents a modern complement to previous analyses. The fatty acid pattern of 3 additional commerical table oils suggest an amalgamation with fats of other types, among which are 2 cases of mixture with rapeseed oils. For mayonnaise, soya oil is used almost exclusively as a fat component. The presence of sunflower oil was only confirmed in one brand of mayonnaise. The concentrations of cholesterol which were determined lie between 17.0 and 72.3 mg (average 53 mg) per 100 g mayonnaise, so that even in the case of persons which present an elevated risk of atherosclerosis there can be no objection to the consumption of mayonnaise. The nutritive-physiological significance of these various oils for human nutrition is thoroughly discussed. A possible health hazard is the sale of vegetable oils rich in erucic acid permitted in the West German Republic (proportion of erucic acid in the 8 samples examined: 223-53%). These vegetable oils, as is shown by the additionally indicated trade names with the corresponding supplementary specifications are overwhelmingly labelled as vegetable oil (Pflanzen?l) or table oil (Speise?l). The purchase prices indicated and paid by us for the oils examined are subject to considerable fluctuations even for oils of the same quality.     

The use of decapitated insects to study lipid mobilization in adult Manduca sexta: effects of adipokinetic hormone and trehalose on fat body lipase activity

In order to perform studies on lipid mobilization in adult M. sexta, it is necessary to overcome the effects of starvation and handling, which both provoke an increase in hemolymph lipid concentration. When trehalose was injected into intact insects, a 35% decrease in the content of the diacylglycerol (DG)-rich hemolymph lipoprotein, low density lipophorin (LDLp) was observed within 30 min, but the level of LDLp returned to control values after 1 h. Decapitated insects exhibited 60% reduction in LDLp concentration and the levels remained low for at least 24 h. In contrast to intact insects, injection of trehalose into decapitated animals did not alter the LDLp concentration. After decapitation, the response to adipokinetic hormone (AKH) and the ability of the fat body to release DG into the hemolymph was maintained for at least 24 h. In decapitated insects, 6 pmol of AKH-stimulated measurable lipid mobilization and a near maximum response was obtained with 100 pmol of the hormone. The action of trehalose and AKH on the fat body triacylglycerol (TG)-lipase activity in decapitated animals was studied. Fat body homogenates from trehalose-treated insects exhibited a TG-lipase activity 40% lower than the control insects. Activation of fat body triacylglycerol-lipase was observed after injection of AKH, with the extent of activation ranging between 97 and 380% ten min after AKH injection. A time course study showed that the activation of the fat body triacylglycerol lipase preceded the increase in hemolymph LDLp concentration, suggesting that activation of the lipase initiates lipid mobilization. It is concluded that decapitated insects injected with trehalose is a very useful system for investigating the hormonal regulation of lipid mobilization in adult M. sexta.     

Adipokinetic hormone-induced lipolysis in the fat body of an insect, Manduca sexta: synthesis of sn-1,2-diacylglycerols

The pseudocontact shifts of NMR signals, which arise from the magnetic susceptibility anisotropy of paramagnetic molecules, have been used as structural constraints under the form of a pseudopotential in the SANDER module of the AMBER 4.1 molecular dynamics software package. With this procedure, restrained energy minimization (REM) and restrained molecular dynamics (RMD) calculations can be performed on structural models by using pseudocontact shifts. The structure of the cyanide adduct of the Met80Ala mutant of the yeast iso-1-cytochrome c has been used for successfully testing the calculations. For this protein, a family of structures is available, which was obtained by using NOE and pseudocontact shifts as constraints in a distance geometry program. The structures obtained by REM and RMD calculations with the inclusion of pseudocontact shifts are analyzed.     

Giant input neurons of the mushroom body: intracellular recording and staining in the cockroach

Covalent complexes of nucleic acids and proteins are widespread among viruses. Covalent complexes of RNA and proteins are proposed to exist in eukaryotic cells. The goal of this work was to obtain specific antibodies to the covalent linkage unit (CLU) between virus RNA and protein to search cellular RNA-protein complexes. Antibodies were generated by direct immunization of a rabbit with the BSA-coupled EMC virus RNA-VPg complex. By a dot-blot immunoassay and immunofluorescent microscopy it was found that the antibodies specifically recognize both EMC virus RNA-VPg and synthetic CLU-containing compounds. Thus, a fraction of the antibodies was directed to CLU.     

Molecular cloning of German cockroach (Blattella germanica) allergens

Allergens produced by cockroaches (CRs) are an important cause of IgE antibody responses and asthma. Using molecular cloning and nucleic acid hybridization techniques, we have identified and sequenced several important allergens produced by the German CR (Blattella germanica) and studied their expression in the American CR (Periplaneta americana). Principal allergens include Bla g 2 (36-kD protein) and Bla g 4 (21-kD protein), to which 60-70% of CR-allergic patients make IgE antibodies. Bla g 2 is only expressed by B. germanica, whereas DNA encoding Bla g 4 is present in P. americana, but is not transcribed into mRNA. Sequence homology searches have identified Bla g 2 as an aspartic protease and Bla g 4 as a calycin. Other CR allergens that have been cloned include a glutathione transferase and a troponin. These studies will enable recombinant allergens to be expressed and used to investigate the role of CR allergens in asthma.