bluuebunny/crossref_metadata_2025 huggingface dataset:
Regional distribution and substrate specificity of digestive enzymes involved in terminal digestion in Musca domestica hind‐midguts
Authors: Jordāo Beatriz P. , Terra Walter R.
Published: February 2005

One membrane‐bound α‐glucosidase and two soluble α‐glucosidases were isolated from homogenates of the hind‐midgut, the main digestive region in Musca domestica larvae. The membrane‐bound α‐glucosidase and the low‐Mr soluble α‐glucosidase hydrolyze maltopentaose better than maltose, maltotriose, and maltotetraose, the reverse being true for the high‐Mr soluble α‐glucosidase. A membrane‐bound glucoamylase previously described in Musca domestica midgut was shown by gradient centrifugation and dialysis against EDTA to result from the combined action of an amylase and an α‐glucosidase. The determination of amylase, α‐glucosidases, soluble and membrane‐bound carboxypeptidase A, membrane‐bound aminopeptidase and dipeptidase along the tissue and luminal contents of the hind‐midgut is described. The data support a proposal concerned with how starch and protein are digested in Musca domestica larval hind‐midguts and where and how midgut glycosidases and peptidases are secreted.
Dsp28: A desiccation stress protein in Tenebrio molitor hemolymph
Authors: Kroeker Ernest M. , Walker Virginia K.
Published: February 2005

A novel hemolymph protein from Tenebrio molitor associated with desiccation stress has been purified and characterized. The protein contains cysteine; it was labeled in vivo using [35S]‐cysteine, and the amino acid analysis showed a 4% cysteine content. In the native state dsp28 is a dimer with a single subunit Mr of 28,000. The synthesis of dsp28 and its concentration in larval hemolymph increase dramatically after desiccation. Dsp28 is a major component of total larval hemolymph protein representing 5% of total protein in control insects and up to 17% in desiccated larvae. The hemolymph of cold‐acclimated larvae also contains elevated levels of dsp28.
Effect of a juvenile hormone analogue on the life span, egg laying, and ecdysteroid titer of virgin Ephestia cautella females
Authors: Shaaya Eli , Calderon Moshe , Pisarev Vladimir , Spindler Klaus‐Dieter
Published: February 2005

Mated females of the tropical warehouse moth, Ephestia cautella, start laying eggs shortly after adult emergence. All eggs are laid within 4 days and the adult's total life span is 5 to 6 days. If mating is prevented, egg laying is drastically delayed and the life span is extended to approximately 10 to 11 days. Virgin females lay fewer eggs than mated insects. If the juvenile hormone analogue methoprene is applied topically (100 ng/pupa) 2 to 3 days prior to adult emergence, the number of eggs per virgin female increases and the life span is reduced, as compared with nontreated virgins, and reaches values similar to control (mated) females. Changs in the ecdysteroid titer of females are related to egg laying. The concentrations increase and reach a maximum before most of the eggs are laid. Accordingly, the peak maximum is delayed in virgins as compared with mated females. This delay is prevented after application of methoprene. Mated and virgin females have lower ecdysteroid levels than treated virgins. In contrast to mated females, males have much lower ecdysteroid levels throughout their adult life.
Phytochemicals at the plant‐insect interface
Authors: Shapiro Jeffrey P.
Published: February 2005

Opportunities for genetic engineering of natural products are increasing, while discovery and development of synthetic insecticides and developmental regulators are declining. However, discovery and potential applications of natural compounds are constrained by present ecological knowledge and theory. Biochemistry offers additional perspective to chemical interaction across the interface between plant and herbivore. Phytochemical effects on an insect herbivore may be determined by physical, chemical, and biotic characteristics of the microenvironment during phytochemical transfer between plant and insect. The midgut lumen is often overlooked as part of this microenvironment. It initially determines rates of metabolism and uptake of phytochemicals into hemolymph, and ultimately the quantity of a compound seen by affected tissues. Additive processes such as absorption, binding, and transport by proteins in hemolymph may ultimately prove more crucial to toxication than subtractive processes such as metabolism and excretion. Uptake and transport of coumarins in hemolymph are being studied in larvae of the citrus root weevil Diaprepes abbreviatus. Studies with synthetic 7‐amino‐3‐phenyl coumarin (coumarin‐10) have preceded studies with natural coumarins. The fluorescence properties of coumarin‐10 have enabled determination of absorption and binding to hemolymph proteins.
Comparative processing of allelochemicals in the Papilionidae (Lepidoptera)
Authors: Berenbaum May R.
Published: February 2005

Within the family Papilionidae (Lepidoptera), species display a broad range of feeding patterns, from oligophagy on a single hostplant family to polyphagy on over a dozen families. Accompanying this diversity of feeding strategies is a diversity of physiological mechanisms for processing hostplant allelochemicals. Studies on members of this family as well as other Lepidoptera suggest that oligophagy is associated with high activity, in addition to high substrate specificity, of detoxicative enzymes.
Plant and insect cuticular lipids serve as behavioral cues for insects
Authors: Espelie Karl E. , Bernays Elizabeth A. , Brown John J.
Published: February 2005

The roles of plant and insect cuticular lipids in insect and plant interactions are reviewed. Emphasis is given to the influence that the host plant and the surface lipids of the host plant have upon insect herbivores and the predators and parasitoids of these herbivores. Variations in cuticular lipids of herbivorous insects are dependent upon the host plant, and these variations may affect the behavior of predators and parasitoids. The cuticular lipids of species which interact on multiple trophic levels are compared. Similarities were found between the hydrocarbons of herbivorous insects, their host plants, and their predators or parasitoids.
Ecdysteroid synthesis and molting by the tobacco hornworm, Manduca sexta, in the absence of prothoracic glands
Authors: Sakurai Sho , Warren James T. , Gilbert Lawrence I.
Published: February 2005

When a pair of prothoracic glands (PGs) were removed from Manduca sexta pupae on the day of pupation, the hemolymph ecdysteroid titer remained at a low level. When a portion of the gland pair was extirpated from pupae after the critical period for prothoracicotropic hormone release, the maximum hemolymph ecdysteroid titer was reduced in proportion to the mass of the PGs removed. These findings clearly showed that the PGs in intact pupae are responsible for the elevated ecdysteroid titer required to elicit adult development on schedule. When brains were removed on the day of pupation, the initiation of adult development was delayed for weeks or months. In contrast, pupae whose PGs were removed on the day of pupation initiated development only 7 days late, indicating the existence of an additional source of pupal ecdysteroids. Further, abdomens of male M. sexta that were isolated on the day of pupation initiated adult development spontaneously within 70 days. The implantation of day 0 pupal brains into these isolated abdomens accelerated the initiation of adult development and elicited synchronous adult development. The hemolymph ecdysteroid titer of those isolated abdomens receiving implants of brains increased within 5 days and reached a maximum level of 1.5 μg/ml. The analysis of hemolymph ecdysteroids by reverse‐phase HPLC revealed that ecdysone was the major moiety and that the ecdysteroid composition was similar to that of normal, intact pupae that had just initiated adult development. These results demonstrate that the PGs are not requisite for adult development. An increased hemolymph ecdysteroid titer was also observed in isolated abdomens from which the testes were removed and in abdomens devoid of their digestive tract. Indeed, in the latter case, the ecdysteroid titer attained much higher levels than those observed for abdomens with intact guts. Despite numerous attempts to identity the tissue(s) in the isolated abdomens responsible for the increase in ecdysteroid titer, its identity remains unknown.
Stage‐specific protein and mRNA synthesis during morphogenesis of the polyembryonic parasitoid Copidosoma floridanum (Ashmead) (Hymenoptera: Encyrtidae)
Authors: Baehrecke Eric H. , Strand Michael R. , Williamson Judy L. , Aiken Judd M.
Published: February 2005

Changes in protein and mRNA synthesis during embryonic morphogenesis of the polyembryonic parasitoid Copidosoma floridanum were characterized by 1‐ and 2‐dimensional gel electrophoresis and quantified by scanning densitometry. Analysis of protein synthesis at different developmental stages indicated that embryonic molecular changes occurred at 36 h of the host's fourth stadium. These changes included decreased expression of 51 and 104 kD (D) proteins and increased expression of 22, 22.5, and 24 kD (D) proteins. Similarly, analysis of in vitro translation products indicated increased transcription of mRNA encoding 16 and 49 kD proteins in embryos dissected at 36 h of the host's fourth stadium. The stage‐specific changes in transcription and translation corresponded to the blastula stage of embryonic development and arose several hours before the initiation of embryonic morphogenic events associated with larval pattern formation. Application of the JH analogue methoprene at times that block morphogenesis but not blastula formation did not block the stage‐specific synthesis of any proteins. In contrast, neck ligation of hosts at times that block blastula formation and morphogenesis inhibited the synthesis of the 24 kD protein that was normally expressed at the blastula stage.
Heat shock proteins and thermotolerance in a cultured cell line from the Mediterranean fruit fly, Ceratitis capitata
Authors: Jang Eric B.
Published: February 2005

Heat shock proteins (hsps) were identified in a cell line from the Mediterranean fruit fly, Certatitis capitata Wiedemann (Diptera: Tephritidae) exposed to elevated temperatures. Cells produced three hsps (Mr 87,000, 69,000, and 34,000) in response to a temperature shift from 26°C to 37°C (30–60 min) with a concomitant decrease in synthesis of most other cellular proteins. Synthesis of low Mr hsps was not evident. The heat shock response is triggered within 30 min at temperatures from 33°C to 41°C. At temperatures >41°C protein synthesis was shut down. Within 2–3 h after return to 26°C, synthesis of proteins repressed at the higher temperatures resumed production while the major hsps disappear. Heat shock proteins were not produced in the presence of actinomycin D. Evaluations on the role of hsps in conferring thermotolerance to the cells showed an increase in cell viability in heat‐shocked cells over nonheat‐shocked cells (after 3 and 10 days) when subsequently placed at 45°C for 1 h, a normally lethal temperature. Heat shock alone had little effect on subsequent cell viability or growth at 26°C. These results suggest that hsps produced by these cells may aid in the maintenance of cell integrity and thus play a transitory role in thermotolerance.
Transfer of phospholipids from fat body to lipophorin in Rhodnius prolixus
Authors: Atella Geórgia Corrêa , Gondim Katia Calp , Masuda Hatisaburo
Published: February 2005

32P‐Labeled fat bodies (32P‐fat bodies) of Rhodnius prolixus females were incubated in the presence of nonradioactive purified lipophorin and the release of radioactivity to the medium was analysed to answer the question of whether lipophorin is a reusable shuttle for phospholipids. The radioactivity found in the medium was associated with lipophorin phospholipids. When the 32P‐fat bodies were incubated in the absence of lipophorin, only a small amount of radioactivity was released and it was not associated with lipophorin, indicating that there was no release of pre‐labeled 32P‐lipophorin by the tissue. Analysis of the 32P‐phospholipids transferred from fat bodies to the lipophorin particles by thin‐layer chromatography revealed a predominance of phosphatidylethanolamine and phosphatidylcholine, with minor amounts of phosphatidylserine, phosphatidylinositol, and sphingomyelin. The transfer of phospholipids to lipophorin was linear with time up to 45 min and the process was inhibited at low temperature and by the metabolic inhibitors azide and fluoride. The transfer of phospholipids from the fat bodies to lipophorin was saturable with respect to the concentration of lipophorin, which was half‐maximal at about 8 mg/ml. A directional movement of phospholipids from the fat body to lipophorin was observed. The net gain of phospholipids in 2 h of incubation with fat body was 8.54 nmol per insect, which corresponds to 6.69% of increase in the lipophorin phospholipid content. The rate of 32P‐phospholipid transfer from fat body to lipophorin particles varied during the days after a blood meal increasing up to day 10 and then decreasing in parallel with the process of oogenesis.
Preliminary characterization of enzyme activities in Malpighian tubules involved in the breakdown of adipokinetic hormones
Authors: Siegert Karl J. , Mordue William
Published: February 2005

Adipokinetic hormones (AKH) from different insect species, crustacean red pigment‐concentrating hormone (RPCH), and synthetic substrates were used to characterized enzyme activities present in the Malpighian tubules (MT) of the desert locuts, Schistocerca gregaria, which are involved in the degradation of AKH.

When peptides containing proline (position 6) were incubated with MT homogenate they were cleaved by a post‐proline cleaving enzyme (PPCE). The presence of such an enzyme was confirmed by the breakdown of a synthetic substrate for PPCE. Peptides which do not contain proline were broken down by a post‐phenylalanine cleaving enzyme (PFCE) which could be chymotrypsin or chymotryptic. This PFCE activity(ies) seem(s) to be inactive on the proline‐containig peptides or their fragments or digests these at a slow rate. The C‐terminal chymotrypsin fragments of the AKHs were broken down by MT homogenates with no accumulation of new intermediate products. It is not clear whether another endopeptidase, PPCE, or leucine aminopeptidase (LAP) is responsible.

The MTs contain LAP activity; however, this enzyme(s) may be different from its vertebrate counterpart(s). Homogenates of MTs break down equimolar amounts of Pro‐7AMC at approximately the same rate, while porcine kidney LAP (cytosol) cleaved Pro‐7AMC much slower than Leu‐7AMC.

The demonstration of carboxypeptidase (CP) A and B activity in the MTs was not possible using conventional substrates such as hippuryl derivatives of amino acids. When CPA from porcine pancreas was added to MT homogenates hippuryl‐phenylalanine was digested proving that the conditions were appropriate for CPA activity to occur. The treatment of a N‐terminally blocked peptide fragment with MT homogenate led to the breakdown of the peptide giving evidence that the MT CP requires a substrate with a somewhat longer length of amino acid residues.
Host regulation effects on Heliothis virescens (F.) larvae inducd by teratocytes of Cardiochiles nigriceps Viereck (Lepidoptera, Noctuidae‐Hymenoptera, Braconidae)
Authors: Pennacchio Francesco , Vinson S. Bradleigh , Tremblay Ermenegildo
Published: February 2005

Teratocytes deriving from the serosal membrane of Cardiochiles nigriceps Viereck, obtained “in vitro” from embryos hatched on a semidefined medium, were injected at different numbers and in different developmental stages of nonparasitized Heliothis virescens (F.) last instar larvae. Host development was affected by teratocyte injections and the responses registered ranged from normal to complete inhibition of pupation, according to the number of teratocytes injected and the developmental stage of the larva at time of injection. Complete pupation failure was observed when teratocytes derived from 4C nigriceps embryos were injected into 1st day 5th instar (new‐slender stage) host larvae. Complete pupation occurred when teratocytes from 2 embryos were injected into 3rd or 4th day 5th instars (burrow‐digging or day 1 cell formation stage). Intermediate responses, such as the formation of pupal cuticle without ecdysis or with only partial ecdysis, were obtained with intermediate teratocyte numbers, or host developmental stages. All pupae derived from teratocyte injected larvae failed to develop into adults normally obtained from control injected larvae. The larval weight just before pupation was negatively affected only when teratocyte injections were performed on 1st day 5th instar H. virescens larvae.

Teratocyte injections altered the hemolymph protein titer to a level similar to that occurring in parasitized larvae. At the same time the ecdysteroid titer was characterized by a late significant increase, which reached values almost 3 times greater than found in normally parasitized larvae, and also surpassed the highest values registered for nonparasitized larvae. Ligation of parasitized larvae between the meso‐ and metathorax demonstrated that when the prothoracic glands were excluded, there was almost no ecdysteroid production posterior to the ligation. Ligations performed on parasitized larvae to isolate parasitoid eggs before hatching in the last abdominal segments, demonstrated that only virus and venom determined a reduction of the ecdysteroid titer. On the basis of these results the possible role of teratocytes in affecting the biological activity of ecdysteroids is postulated and discussed in a wider context of host‐parasitoid physiological interactions.
Regulation of fat body glycogen phosphorylase activity during refeeding in Manduca sexta larvae
Authors: Siegert Karl J. , Mordue William
Published: February 2005

In 12‐h‐starved larvae of the tobacco hornworm, Manduca sexta, fat body glycogen phosphorylase was quickly inactivated when insects were refed with normal diet and agar which contained 3% sucrose. Only the first 2 min of refeeding were necessary to induce enzyme inactivation. During this short period, larvae did not ingest enough sucrose to increase the hemolymph glucose concentration. This may indicate that the gut released a hormone(s) which directly or indirectly led to the inactivation of fat body glycogen phosphorylase.

Inactivation of the enzyme could also be induced by injection of glucose (30 mg) into the hemolymph of starving M. sexta larvae suggesting that there may be separate control from a neuroendocrine site such as the brain or the corpora cardiaca. Trehalose was less effective.

Bovine insulin (2 and 4 μg/starved larva) did not induce phosphorylase inactivation over 20 min or decrease hemolymph carbohydrate or lipid concentrations within 60 min. It is, therefore, necessary to screen insect tissues for substances which could bring about inactivation of fat body glycogen phosphorylase. © 1992 Wiley‐Liss, Inc.
Effects of prococene II on the nutritional physiology of last instar Heliothis zea larvae
Authors: Binder Bradley F. , Bowers William S.
Published: February 2005

When precocene II was fed to last instar larvae of Heliothis zea, it caused significant reductions in the calculated rate of growth, rate of nutrient assimilation, and conversion of ingested and digested food to body mass. No change in the rate of food consumption occurred but respiration was significantly higher. Transport of the nutrient [1‐14C] linoleic acid across midgut tissue was hindered when larvae were fed precocence II. There was also a precocene‐induced change in the apical (luminal) morphology of midgut cells, including absence of the glycocalyx and loss of the microvillar absorptive surface. The influence of precocene II on the midgut physiology and metabolic processes in last instar larvae of H. zea may account for the observed reduced growth and delayed development. © 1992 wiley‐Liss, Inc.
Immunochemical and biological analysis of pheromone biosynthesis activating neuropeptide in Heliothis peltigera
Authors: Gazit Yoav , Dunkelblum Ezra , Ben‐Aziz Orna , Altstein Miriam
Published: February 2005

This study describes the preparation and characterization of a highly specific antiserum to Helicoverpa zea pheromone biosynthesis activating neuropeptide (Hez‐PBAN), and the use of thsi antiserum, in an enzyme linked immunosorbent assay (ELISA), to determine: (a) the content of endogenous PBAN in head extracts of male and female Heliothis peltigera; (b) the level of PBAN at different developmental stages; and (c) the content of PBAN in four different moth species. Cross‐reactivity studies revealed that the antiserum is directed mainly toward the N‐terminal region of the neuropeptide, and that it exhibits similar binding affinities toward the oxidized and reduced forms of PBAN. Analysis of PBAN content in head extracts of male and female H. peltigera, at scotophase, revealed the presence of 4.97 and 4.58 pmol, respectively, in 3‐day‐old moths, and 5.33 and 4.78 pmol, respectively, in 7‐day‐old moths. The similarity in the content of PBAN at both ages and sexes was in accordance with the amount of pheromonotropic activity in these extracts which stimulated pheromone biosynthesis to a similar level. Analysis of PBAN‐like immunoreactivity (IR) in head extracts of H. peltigera larvae and pupae demonstrated the existence of the neuropeptide in the 4th larval instar and continued to increase as a function of development. No IR could be detected in the first three larval instars. The larval and pupal extracts also exerted pheromonotropic activity which followed a similar pattern. The activity in these extracts, however, was considerably lower than that found in adult male and female heads. IR was also detected in head extracts of three other Noctuidae moths: Helicoverpa armigera, Cornutiplusia circumflexa and Spodoptera littoralis, indicating a high degree of chemcial and structural similarity of PBAN in these moths. © 1992 Wiley‐Liss, Inc.
Lipophorin lipase from the yolk of Manduca sexta eggs: Identification and partial characterization
Authors: Van Antwerpen Rik , Law John H.
Published: February 2005

In the hawkmoth Manduca sexta high density lipophorin from adult insects (HDLp‐A) delivers lipids to developing oocytes. During this lipid delivery HDLp‐A is taken up by the oocyte and converted to a very high density lipophorin (VHDLp), which is stored in protein storage granules (yolk bodies). A membrane‐free lysate of isolated M. sexta yolk bodies was demonstrated to contain lipoprotein lipase activity that hydrolyses the diacylglycerol of HDLp‐A. With HDLp‐A as a substrate yolk body lipophorin lipase (YBLpL) activity was shown to be maximal between pH 9 and pH 9.5. NaCl concentration was optimal between 0.7 M and 1 M. YBLpL activity required neither bovine serum albumin nor calcium ions but appeared to be stimulated by 5 mM EDTA. Diisopropyl fluorophosphate effectively inhibited YBLpL activity, indicating the presence of a serine in the active site of the enzyme. The identified lipase activity co‐eluted with lipophorins and vitellins from the yolk in the void volume of a Sephadex G‐75 gel filtration column. This observation suggests that the lipase has a Mr of more than 80,000, or that the enzyme is associated with the lipoproteins. Incubation of HDLp‐A with yolk body lysate converted HDLp‐A to two classes of higher density lipophorins. The highest density lipophorins produced during this incubation approached the density of VHDLp as it is isolated from mature eggs. The possible role of YBLpL activity in the delivery of lipids to developing oocytes is discussed. © 1992 Wiley‐Liss, Inc.
Sterols and symbiosis in the leaf‐cutting ant Acromyrmex octospinosus (Reich) (Hymenoptera, Formicidae: Attini)
Authors: Maurer Patricia , Debieu DanièLe , Leroux Pierre , Malosse Christian , Riba Guy
Published: February 2005

The leaf‐cutting ants Acromyrmex octospinosus live in symbiosis with a fungus they cultivate on leaf fragments. The symbiote forms characteristic hyphal apical swellings called “gongylidia,” which are consumed in preference to the mycelium by the ants. However, the ants also ingest fluids derived from the plant leaves they handle to make the culture substrate. The 4‐desmethylsterols of the ants were essentially (83%–94% of total 4‐desmethylsterols) Δ5,7‐sterols which were identified as ergosta‐5,7,24(28)‐trien‐3β‐ol, ergosta‐5,7‐dien‐3β‐ol, and ergosterol. These Δ5,7‐sterols were all found in the gongylidia, whereas ergosterol mainly was found in the mycelium. Some Δ5‐sterols were detected in the whole body, as well as in the expressed rectal fluid of the ants which partly contains the nonabsorbed material. However, the rectal fluid, as compared to the whole body, contained much higher amounts of Δ5‐sterols originating mainly from the plant leaves. Leaf‐cutting ants preferentially retained Δ5,7‐sterols originating from the specialized gongylidia formed by the fungal symbiote, from a mixed diet of fungal and plant leaf sterols. © 1992 Wiley‐Liss, Inc.
Mode of action studies on a Manduca sexta diuretic hormone
Authors: Troetschler Ruth G. , Kramer Steven J.
Published: February 2005

The mode of action of a diuretic hormone from pharate adult Manduca Sexta heads, which triggers fluid loss in M. sexta larvae and Pieris rapae adults, was studied. In vivo, Mas‐DH (M. sexta diuretic hormone) decreased fluid absorption from larval recta, and increased levels of the second messenger cAMP in recta and Malpighian tubules (Mt) from larvae, and in fat body of larvae and adult M. sexta. In vitro, Mas‐DH triggered minor changes in fluid loss from adult Mt, but did not affect levels of cAMP in Mt from larvae, pharate adults, or adults, though it elevated cAMP levels in fat body of these stages. © 1992 Wiley‐Liss, Inc.
Storage proteins are present in the hemolymph from larvae and adults of the Colorado potato beetle
Authors: Koopmanschap Bertha , Lammers Hans , De Kort Stan
Published: February 2005

The protein composition of larval and adult hemolymph from the Colorado potato beetle, Leptinotarsa decemlineata, was investigated and some abundant, high molecular weight proteins were identified and characterized. Diapause protein 1, which occurs in the hemolymph of last instar larvae and short‐day adults, appeared to be a storage protein. This protein dissociated into two bands due to the high pH used in nondenaturing gels. Its quaternary structure was established by chemical crosslinking. It appeared to be a hexamer. Diapause protein 1 is composed of ≈82,000 subunits. The amino acid composition and N‐terminal sequence of this protein has been determined. Specific antibodies against diapause protein 1 have been developed. Topical application of 1 μg pyriproxyfen, a juvenile hormone analog, to last instar larvae and short‐day adults suppressed the appearance of this protein in the hemolymph. Pyriproxyfen prematurely induced vitellogenin, when applied to last instar larvae.

A larval specific protein was also identified in the hemolymph. Its temporary appearance in the hemolymph of last instar larvae, its subunit composition (Mr ≈82,000) and its suppression by pyriproxyfen suggests that this protein is a storage protein as well. © 1992 Wiley‐Liss, Inc.
Allatotropin‐Induced formation of inositol phosphates in the corpora allata of the moth, Manduca sexta
Authors: Reagan Jeff D. , Miller Wilma H. , Kramer Steven J.
Published: February 2005

Allatotropin (AT) is a 13 amino acid neuropeptide isolated from the tobacco hornworm, Manduca sexta, which stimulates the biosynthesis of juvenile hormone (JH) in adult females of this insect. In this paper we report that AT stimulates inositol phosphate formation in both female and male corpora allata (CA) of adult Manduca sexta. Furthermore, thapsigargin, a potent Ca2+‐ATPase inhibitor, staurosporine, a potent inhibitor of protein kinases A and C, and 2,5‐di‐(tert‐butyl)‐1,4‐hydroquinone (DBHQ), a potent inhibitor of liver microsomal ATP‐dependent Ca2+ sequestration, all stimulate JH biosynthesis without changing the basal level of inositol phosphates. These data suggest that AT activates an inositol 1,4,5‐trisphosphate (IP3) pathway. Furthermore, increases in the free intracellular Ca2+ concentration in the CA stimulate JH biosynthesis. © 1992 Wiley‐Liss, Inc.
Photoperiod cues and the modulatory action of octopamine and 5‐hydroxytryptamine on locomotor and pheromone response in male gypsy moths, Lymantria dispar
Authors: Linn Charles E. , Campbell Marlene G. , Roelofs Wendell L.
Published: February 2005

Experiments were conducted to determine whether the biogenic amines octopamine (OA) and 5‐hydroxytryptamine (5‐HT) exert modulatory effects on pheromone responsiveness and random locomotor activity in male gypsy moths. When injected into males, OA significantly enhanced sensitivity to pheromone, while 5‐HT enhanced general locomotor activity, results that were very similar to those previously shown for the cabbage looper. Maximal effect of the amines, however, was observed when injection occurred just prior to the onset of scotophase, rather than photophase, as we had originally hypothesized for this diurnally active insect. Male gypsy moths also displayed a prominent scotophase response, with sensitivity to pheromone greater in the scotphase compared with photophase, but with the level of random locomotor activity lower in scotophase than in photophase. The upwind flight behavior of males to a pheromone source in a wind tunnel, as well as the time spent at the source, were also significantly different in the two light regimes. Furthermore, when exposed to a 1 h scotophase (instead of the normal 8), or to continuous dark conditions, while males exhibited response to pheromone and locomotor activity during the same scotophase and photophase periods as observed in a 16:8 light : dark cycle, the levels of response, as well as qualitative aspects of the upwind flight behaviors in both periods were a function of the light intensity. Our combined results suggest that male gypsy moths display a bimodal rhythm of locomotor and pheromone response over the diel cycle, with light intensity and scotophase onset providing critical cues for the expression of behaviors, as well as the modulatory action of the amines. © 1992 Wiley‐Liss, Inc.
Role of photoperiod cues in regulating the modulatory action of octopamine on pheromone‐response thresholds in the cabbage looper moth
Authors: Linn Charles E. , Roelofs Wendell L.
Published: February 2005

Experiments were conducted to determine the relationship between photoperiod cues and the modulatory action of octopamine (OA) on male sensitivity to sex pheromone in the cabbage looper moth. Results showed that levels of random locomotor activity and response to pheromone, as well as the effectiveness of OA in enhancing male sensitivity, were dependent on the light intensity during the scotophase period. The importance of scotophase onset was further demonstrated by the fact that a 1 h period of dark (instead of the normal 8) was sufficient to elicit male response to pheromone, and the modulatory action of the amine, several hours later in photophase conditions during the “expected” mid‐scotophase period when peak response normally occurs. Furthermore, expression of the response rhythms and the effect of octopamine were maximal when injection of the amine and scotophase onset occurred during a narrow temporal window around the expected time of scotophase onset. Delays or advances in scotophase onset or injection of octopamine resulted in decreased levels of behavior and loss of effectiveness of the amine. Studies involving a reversal in the photoperiod also support the idea that scotophase onset is a critical time in the regulation of the general locomotor and pheromone‐response rhythms exhibited by males. The combined results support a hypothesis that the modulatory action of octopamine is associated with physiological changes occurring at the onset of scotophase, and that the periodicity of this action is influenced by an endogenous oscillator. © 1992 Wiley‐Liss, Inc.
Development of specific RIA and ELISA to study trypsin modulating oostatic factor in mosquitoes
Authors: Borovsky Dov , Powell Charles A. , Carlson David A.
Published: February 2005

Trypsin modulating oostatic factor (TMOF), a decapeptide (H‐YDPAPPPPPP‐OH) that signals the termination of trypsinlike enzyme biosynthesis in the mosquito midgut, was covalently bound to Keyhole Limpet Hemocyanin using N‐hydroxysuccinimide and dicyclohexylcarbodiimide. Polyclonal antibodies raised in rabbits against this conjugate were used to develop specific RIA and enzyme linked immunosorbent assay (ELISA) to detect the peptide hormone in female Aedes aegypti. TMOF and its analogs TMOF(B) (H‐DYPAPPPPPP‐OH), P4 (H‐YDPAPPPP‐OH), P1 (H‐YDPAP‐OH), and poly‐L‐proline were tested with the antiserum. The antiserum fully recognized TMOF and partially recognized P4. Using both RIA and ELISA, we report that the amount of TMOF in the mosquito ovary is 100 ± 20 ng (S.E.) and 96 ± 1.4 ng (S.E.), respectively, for each assay. Minute quantities of TMOF a thousandfold lower than in the ovary were found in the mosquito brain, indicating that the hormone is probably not neural but ovarian in origin. © 1992 Wiley‐Liss, Inc.
3‐Oxoecdysteroid reductases in Manduca sexta midgut
Authors: Weirich Gunter F. , Svoboda James A.
Published: February 2005

The 80,000g supernatant o larval midgut homogenates of the tobacco hornworm, Manduca sexta, was fractionated by affinity chromatography on Blue Sepharose CL‐6B and by anion exchange chromatography on Q Sepharose. Both methods resolved one major 3‐oxoecdysteroid 3α‐reductase and three major 3‐oxoecdysteroid 3β‐reductases. The 3β‐reducates reacted only with BADPH as cosubstrate. The 3α‐reductase was active with both NADPH and NADH, and the NADPH/NADH activity ratio increased with the NaCl concentration (0–0.5 M) in the incubation mixtures. The 3‐α‐reductase and one of the 3‐β‐reductases showed very similar chromatographic properties, and their isoelectric points were 5.2 and 5.8, respectively. © 1992 Wiley‐Liss, Inc.
Lipid composition of the pea aphid, Acyrthosiphon pisum (Harris) (homoptera: Aphididae), reared on host plant and on artificial media
Authors: Febvay Gérard , Pageaux Jean‐François , Bonnot Guy
Published: February 2005

Polar and neutral lipids and their constitutive fatty acids were quantified in the pea aphid, Acyrthosiphon pisum (Harris), grown on host plant or on a lipid free artificial diet. The results were compared to determine if lipids were involved in the suitability of the diet for continuous rearing of this A. pisum biotype. For apterous adults grown on plants, the lipids were characterized by a low amount of neutral lipids (2.5% weight/fresh weight) almost entirely (96.4%) composed of hexanoyl and sorboyl dimyristin. These storage lipids were higher in the alatae (3.8%), probably correlated with potential flight activity. The phospholipid amounts were identical in these two morphs (1.3–1.4% weight/fresh weight), comprised mainly of phosphatidylethanolamines (52%) and phosphatidylcholines (40.6%). These phospholipids contained a still unidentified fatty acid, with a retention time close to that of linolenic acid and synthesized by the aphid or its bacterial symbionts (not found in plants). The apterous adult aphids reared on an artificial diet showed an accumulation of neutral lipids (8.9% for the first generation); this increase was shown to be slightly greater for the hexanoyl and sorboyl triglycerides. In contrast, the phospholipids decreased in aphids reared on an artificial diet (1.1% and 0.9%, respectively, for first and second generation), correlated with a phospholipid fatty acid profile significantly deficient in C18:3 and in the unidentified peculiar fatty acid. These phospholipids are essential components of biological membranes and a diet‐driven deficient synthesis in some of their components may result in the observed symptoms. © 1992 Wiley‐Liss, Inc.
Biochemical characterization of insect neuronal sodium channels
Authors: Gordon Dalia , Moskowitz Haim , Zlotkin Eliahu
Published: February 2005

The pharmacological uniqueness of the insect sodium channels is indicated by their ability to bind the excitatory and depressant insect selective neurotoxins derived from scorpion venom. The latter were shown to bind and modify sodium conductance exclusively in insect neuronal membranes. The insect sodium channel polypeptides were identified by immunoprecipitation using site‐directed antibody, anti SP19 (corresponding to a highly conserved segment in the sodium channel α subunits), followed by radiophosphorylation and SDS‐PAGE autoradiography. Sodium channel polypeptide in the central nervous system (CNS) of insects belonging to four distinct orders (Orthoptera, Dyctioptera, Diptera, and Lepidoptera) were shown to (1) serve as substrates for phosphorylation by cAMP‐dependent protein kinase; (2) be devoid of disulfide linkage to smaller subunits unlike sodium channels in vertebrate CNS; (3) be glycoproteins as demonstrated by endoglycosidase F treatment and binding to lectins; and (4) reveal a diversity with regard to their apparent molecular mass (Mr 240,000–280,000) and partial peptide maps. The locust sodium channels were functionally solubilized (monitored by [3H]saxitoxin (STX) binding) by 1% cholate, 0.2% Triton X‐100, and 0.22% phosphatidylcholine. About 40% of STX binding activity was recovered in the solubilized fraction without affecting affinity (Kd = 0.5 nM). The time and temperature dependent lability of STX binding activity, in the solubilized fraction, was prevented by 20 nM STX. Partial purification of the insect sodium channel by an anion exchanger yielded 20% recovery and a 3.5 times increase in specific STX binding activity. The presence of a radiophosphorylated 245,000 α‐subunit band coincided with the STX binding activity during purification. In sum, the above information concerning the solubilization and characterization of the insect sodium channel will pave the way to the molecular identification of the receptor sites of the insect selective neurotoxins. © 1993 Wiley‐Liss, Inc.
Insect neuropeptides: Discovery and application in insect management
Authors: Masler Edward P. , Kelly Thomas J. , Menn Julius J.
Published: February 2005

New approaches to the development of insect control agents have been revealed through the molecular description of neuropeptides, their biogenesis, action, and degradation. Prerequisite to the exploitation of a neuropeptide as a lead to control agent development is a thorough understanding of the biochemistry of the neuropeptide and appreciation of its physiological impact. Reliable bioassays must be coupled with advanced biochemical and molecular genetic technologies to overcome limitations imposed by the typically low endogenous levels of individual neuropeptides. Purification, amino acid sequencing, and gene cloning provide the molecular tools necessary for studies on neuropeptide synthesis, processing, secretion, receptor binding, and inactivation. Each of these areas consists of a number of amino acid sequence‐, and enzyme‐dependent steps which may be considered as targets for the development of highly specific control agents. These agents will include antagonists and superagonists, peptidomimetics, recombinant peptides delivered through the baculovirus technology, receptor blockers, and enzyme inhibitors. © 1993 Wiley‐Liss, Inc.
Pheromone biosynthesis activating neuropeptide: From discovery to current status
Authors: Raina Ashok K. , Menn Julius J.
Published: February 2005

Sex pheromone production in females of many species of moths is controlled by a pheromone biosynthesis activating neuropeptide (PBAN). PBAN from Helicoverpa zea (Hez‐PBAN) is a 33 amino acid peptide produced in the suboesophageal ganglion of both female and male moths. PBAN‐like activity is widespread among Lepidoptera and is also reported from a cockroach and a grasshopper. The C‐terminal pentapeptide of Hez‐PBAN represents the minimum sequence with pheromonotropic activity. Another pentapeptide fragment of the molecule also has high pheromonotropic activity. Presence of PBAN‐like immunoreactivity and biological activity in the corpora cardiaca suggests that it is the possible site of PBAN release. There is evidence that PBAN action on pheromone gland is mediated by a second messenger. Several possible sites of action of PBAN have been suggested in the biosynthetic pathway of pheromones. The gene for Hez‐PBAN has been cloned and sequenced. Cloning of a synthetic PBAN gene into a baculovirus has been attempted. Studies to isolate and identify the receptors for PBAN as well as the metabolic fate of PBAN have been initiated. © 1993 Wiley‐Liss, Inc.
Neuroendocrine control of sex pheromone biosynthesis in Heliothis peltigera
Authors: Alstein Miriam , Gazit Yoav , Dunkelblum Ezra
Published: February 2005

Sex pheromone production in female moths is controlled by a cerebral factor termed pheromone biosynthesis activating neuropeptide (PBAN). Our understanding of the sequence of events common to the neuroendocrine process of PBAN, namely, its biosynthesis, secretion, transport, biological activity, and degradation, is very limited. Moreover, some of the studies are controversial, mainly those related to: (1) the route of transport of PBAN to its target organ, (2) the nature of the target organ of PBAN, (3) the possible involvement of other stimulatory and inhibitory neural and nonneural factors in the regulation of sex pheromone biosynthesis, (4) the structure‐function relationship of the neuropeptide, and (5) the effect of PBAN on the enzymatic steps involved in pheromone biosynthesis in the gland. In this work, we summarize the results obtained in our laboratory on the regulation of sex pheromone biosynthesis by PBAN in Heliothis peltigera and shed light on some of these controversial issues. © 1993 Wiley‐Liss, Inc.
Influence of photoperiod and age on the competence of pheromone glands and on the distribution of immunoreactive PBAN in Helicoverpa spp.
Authors: Rafaeli Ada , Soroker Victoria , Hirsch Jaquelyn , Kamensky Batya , Raina Ashok K.
Published: February 2005

Pheromone glands (eighth and ninth abdominal segments) of Helicoverpa spp. can be stimulated in vitro by brain‐suboesophageal ganglion (Br‐SOG) extracts and Helicoverpa zea pheromone biosynthesis activating neuropeptide (Hez‐PBAN) to produce the sex pheromone. The main pheromone component, (Z)‐11‐hexadecenal, was quantified by both TLC and gas chromatographic analyses. This stimulation was shown to be a specific response attributed to pheromone glands alone. The glands were found to be competent to Br‐SOG extracts/Hez‐PBAN stimulation from the first day after emergence during both the photophase and scotophase. Using a sensitive and specific RIA the distribution of PBAN along the central nervous system was studied and PBAN‐immunoreactivity in Br‐SOG complexes was found throughout the photoperiod and in all ages (from the first day of emergence until the fourth night after emergence). From the distribution of PBAN immunoreactivity it appears that PBAN release is affected by the photoperiod. This integrative study on the competence of the target tissue and the distribution of PBAN activity revealed evidence that the neuroendocrine control of pheromone production operates at the level of neuropeptide production and/release and not at the level of the target tissue itself. © 1993 Wiley‐Liss, Inc.
Negatively correlated cross resistance: Combinations of N‐methylcarbamate with N‐propylcarbamate or oxadiazolone for green rice leafhopper
Authors: Yamamoto Izuru , Kyomura Nobuo , Takahashi Yoji
Published: February 2005

The use of insecticide mixtures is generally considered to result in the simultaneous development of resistance to the components. However, experiences with leaf and planthoppers do not necessarily support this opinion and indicate that the N‐methylcarbamate/N‐propylcarbamate combination can overcome the resistance of the green rice leafhopper (GRLH) by synergism between the two components. It was found that the N‐methylcarbamate/oxadiazolone combination gave a similar but more remarkable synergism than the former combination. The mechanism of synergism was studied by the analysis of acetylcholinesterase (AChE) inhibition using the log v‐t plot. AChE from the resistant population is provided with two active sites, one being sensitive to N‐methylcarbamate and oxadiazolone compounds and the other being insensitive to N‐methylcarbamates but highly sensitive to oxadiazolones. The overall results indicate that the biochemical mechanism of action of the N‐methylcarbamat/oxadiazolone combination is essentially the same as that of the N‐methylcarbamate/N‐propylcarbamate combination. Selection of susceptible GRLH by a N‐methylcarbamate developed the cross‐resistance to the whole N‐methylcarbamate group; but the population became more susceptible to N‐propylcarbamates. When further selected by the N‐methylcarbamate/N‐propylcarbamate combination, no further resistance developed to the combination or its components. Thus, certain combinations of insecticides may be useful in resistance management. © 1993 Wiley‐Liss, Inc.
Development of recombinant viral insecticides by expression of an insect‐specific toxin and insect‐specific enzyme in nuclear polyhedrosis viruses
Authors: Hammock Bruce D. , McCutchen Billy F. , Beetham Jeffrey , Choudary Prabhakara V. , Fowler Elizabeth , Ichinose Reiji , Ward Vernon K. , Vickers Joanna M. , Bonning Bryony C. , Harshman Lawrence G. , Grant David , Uematsu Tamon , Maeda Susumu
Published: February 2005

As supplements to classical chemical insecticides, two approaches to develop recombinant baculovirus insecticides are described. In one approach an insect‐specific toxin is expressed leading to a dramatic reduction in time to death. In the second approach an insect juvenile hormone esterase is expressed which leads to a reduction in feeding. Modifications of the wildtype esterase led to viruses which reduced the time to death as efffectively as did the toxin‐expressing virus. In both cases existing recombinant viruses are viewed as leads, and approaches to further improvement in the engineered viruses are suggested. Many of these approaches are based on analogy with the development of classical synthetic insecticides. Using these viruses as examples, the potential utility and limitations of recombinant viruses and other biological insecticides are discussed. © 1993 Wiley‐Liss, Inc.
Insecticidal potential of the insect parvovirus GmDNV
Authors: Tal Jacov , Attathom Tipvadee
Published: February 2005

The insecticidal potential of Galleria mellonella densovirus (GmDNV) in third, fourth, and fifth instar larvae of the host, the greater wax moth, as a step toward the construction of a molecular vector for the introduction and expression of foreign genes in the larvae of these insects was studied. Third instar larvae are most susceptible to GmDNV. Viral RNA synthesis is more rapid in this stage and slowest in the fifth instar. Infection of prepupae by intradermic injection or by horzontal spread inhibited pupation. GmDNV DNA is also infectious when introduced as a calcium phosphate precipitate. The two putative viral promoters were shown to be capable of driving the expression of the reporter gene chloramphenicol acetyltransferase (CAT) in DNA‐injected larvae. © 1993 Wiley‐Liss, Inc.