bluuebunny/crossref_metadata_2025_split huggingface dataset:
Serosal cells of Biosteres longicaudatus (Hymenoptera: Braconidae): Ultrastructure and release of polypeptides
Authors: Lawrence Pauline O. 
Published: February 2005

AbstractAs a prelude to a study in vitro of the function of the embryonic serosa of the parasitic wasp Biosteres longicaudatus (Braconidae), the ultrastructure of serosas of different ages reared in vivo and in vitro were compared. The evidence suggests that the serosal capsule consists of one to three cell layers. The innermost (internal cells) which line the serosal capsule and the outermost (external) cells which are bathed by the host's hemolymph are secretory. Large, coated vesicles in the internal cells increase in number and size with age and, likely, take up and transport molecules into the serosa. Multivesicular bodies, Known for their enzyme‐degradative function, occur in external cells and are eventually extruded into the surrounding environment. Distinctive electrondense, rod‐shaped particles appear in external cells within 8 h after larvae hatch, increase in number with larval age, and occur at the bases of microvilli. The latter appear electron dense with age and eventually they and the lobulated microvilli in internal cells fragment into the surrounding environment. To determine whether parasites and/or their serosas release substances into the host Anastrepha suspensa (Diptera: Tephritidae), hemolymph from unparasitized and superparasitized (> 1 parasite/host) pharate pupae was analyzed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS‐PAGE). Serosas and/or parasite larvae were incubated in artificial media and each of these was subjected to SDS‐PAGE. A polypeptide, approximately 24 kilodaltons (Kd) occurred in the hemolymph of 24‐h‐old superparasitized pharate pupal hosts but not in the control. A similar polypeptide was observed in medium cultured with parasite larva and serosa as well as serosa alone, but was not in their respective control media. This approximately 24‐Kd band in SDS‐PAGE gels corresponds to a band in the serosa homogenate and may be identical to it. Serosas and parasite larvae in vivo and in vitro have similar protein profiles. Based upon these ultrastructural and electrophoretic studies, it appears that the serosa of B. longicaudatus has a synthetic function, as has been reported for the extra‐embryonic membrane of other parasitic Hymenoptera. It may sequester and degrade molecules from the host hemolymph and likely release newly synthesized as well as degraded products into the host.
Eretmocerus penetration and immature development: A novel approach to overcome host immunity
Authors: Gerling Dan , Orion Tamar , Delarea Yaakov 
Published: February 2005

AbstractThe mode of penetration of parasitoids belonging to the genus Eretmocerus into whitefly larvae and their immature development were examined. Examination included scanning electron microscopy and light microscopy of stained and unstained whole mounts and sections.The Eretmocerus larva pierces the venter of its host shortly after hatching, and subsequently enters the host through the same hole. The host reacts by forming a cellular capsule around the Eretmocerus larva. This capsule is incomplete, with an opening in its ventral side opposite the penetration hole. The capsule remains intact during most of the second instar of the parasitoid. It then disintegrates, but its remnants are still visible around the third instar. Whenever two Eretmocerus larvae penetrate, they are surrounded by two capsules. The capsule does not prevent parasitoid development, but it apparently precludes contact of cellular elements of the host's blood with the developing parasitoid larva.Adaptive features of Eretmocerus larval biology include the early contact with the host's internal medium that permits host regulation; and the delay of contact with the host's blood cells that may preclude the need to confront host immunological systems.
Hydrolysis of sphingomyelin and phosphatidylcholine by midgut homogenates of the stable fly
Authors: Spates George E. , Bull Don L. , Chen Andrew C. 
Published: February 2005

AbstractQualitative and quantitative analyses were made to characterize the enzymatic degradation of sphingomyelin and phosphatidylcholine by midgut homogenates of the adult stable fly, Stomoxys calcitrans (L.). The results indicated that sphingomyelin was hydrolyzed by an enzyme with sphingomyelinase‐like properties, and that phosphatidylcholine was hydrolyzed by an enzyme with properties similar to phospholipase C. The optimum pH for the sphingomyelinase was 7.6, and the rate of hydrolysis of sphingomyelin at that pH was linear from 1 to 4 nmol of substrate and 5 to 25 μg of enzyme preparation. Dialysis of the homogenates against Tris‐HCI and imidazole buffers resulted in a decrease of sphingomyelinase activity by 59% and 98%, respectively, and the original activity was not restored with the addition of Ca++, Mg++, or Mn++.
Cloning of the mitochondrial genome of Anopheles quadrimaculatus
Authors: Cockburn Andrew F. , Mitchell Sharon E. , Seawright Jack A. 
Published: February 2005

AbstractThe entire 15 kilobase (kb) Anopheles quadrimaculatus mitochondrial DNA (mtDNA) was cloned as three EcoRI fragments in a bacteriophage vector and then subcloned into plasmid vectors. The cloned DNA was physically mapped with restriction endonucleases, and the maps were compared to the restriction patterns of native A. quadrimaculatus mtDNA. Several genes were mapped by sequencing the ends of A. quadrimaculatus mtDNA subclones and by hybridization with the previously characterized Aedes albopictus mtDNA clones. These portions of the genetic map were identical in gene order to those of Drosophila yakuba. The predicted amino acid sequence of the protein coding regions that were sequenced were between 72% and 98% homologous to D. yakuba. The cloned mtDNA will be useful as a probe for population genetic analysis of mosquitoes.
Modulation of tension production by proctolin in the dorsal longitudinal muscles of the cricket, Teleogryllus oceanicus
Authors: A. O'Gara Bruce 
Published: February 2005

AbstractHigh‐frequency electrical stimulation (∼20 Hz) of the lateral nerve in abdominal segments of the cricket, Teleogryllus oceanicus, caused an increase in tonus of the abdominal dorsal longitudinal muscle (DLM). This effect persisted for 1–5 min following stimulation. Application of the pentapeptide proctolin (threshold 1–10 nM) mimicked the increase in muscle tonus produced by electrical stimulation. Individual twitches were unaffected or slightly reduced by proctolin. Low‐frequency electrical stimulation (<7 Hz) of the lateral nerve counteracted a previously induced increase in muscle tonus, apparently by activation of an inhibitory motoneuron. γ‐Aminobutyric acid (GABA) mimicked the effect of low‐frequency stimulation and reduced muscle tonus. Octopamine, in concentrations of ≤0.1 mM, was inactive on the abdominal DLM when stimulated at low frequencies (0.5–2 Hz). Application of proctolin to the metathoracic DLM caused an increase in twitch amplitude but had little effect on basal tonus. In conjunction with the previously described responses of the metathoracic DLM to octopamine, these results show that the serially homologous abdominal and metathoracic DLMs have dissimilar responses to the modulators proctolin and octopamine.
Lipid biosynthesis in adult Acyrthosiphon pisum: Effect of age and symbiont population
Authors: de Renobales Mertxe , Cripps Colleen , Kinsey Marvin 
Published: February 2005

AbstractThe incorporation of [1‐14C]acetate into total lipids in 1‐day‐old adult pea aphids is 3.3‐fold higher than in 20‐, 22‐, and 24‐day old adults. The polar lipid fraction was the main lipid class synthesized at any age and contained primarily eighteen carbon fatty acids. While the relative mass of 18:0, 18:1 and 18:2 decreased in older aphids, the relative amount of label incorporated into these fatty acids remained constant. Myristic acid was the main fatty acid of the triacylglycerol fraction, and the relative amount of radioactivity incorporated into this fatty acid decreased in older aphids. Twenty‐day‐old aphids had 60% fewer mycetocytes than did 1‐day‐old insects. We conclude that symbionts within the mycetocytes do not appear to be involved in the synthesis of linoleic acid, while their role in the synthesis of myristic acid is less clear.
A simple and rapid technique for identification of large numbers of individual mosquitoes using DNA hybridization
Authors: Cockburn Andrew F. 
Published: February 2005

AbstractA general method for obtaining species‐specific repetitive DNA sequences is described. The method is based on the detection of recombinant DNA clones containing repetitive sequences using labeled total genomic DNA. These repetitive DNA sequences can be used to identify individual mosquito adults, pupae, and larvae squashed on filter membranes (squash blots). This technique was used to distinguish individuals of the four sibling species of the Anopheles quadrimaculatus complex. Repetitive DNA sequences and squash blots can be of use for rapid identification of other insect species in field collections.
Yolk degradation in tick eggs: I. Occurrence of a cathepsin L‐like acid proteinase in yolk spheres
Authors: Fagotto François 
Published: February 2005

AbstractIn crude extracts of eggs of the soft tick Ornithodoros moubata, maximum degradation of vitellin is at pH 3–3, 3.5, whereas no proteolysis is detected at neutral or weakly acidic pHs. Acidic proteolysis is maintained at high level throughout embryonic development, and rapidly decreases in the larva, during the high phase of yolk degradation. Proteinase, acid phosphatase, and N‐acetylglucosaminidase are localized within the yolk spheres; these can be considered as lysosomal‐like organelles containing both substrate (vitellin) and the degradative machinery. Proteolytic activity has been essentially attributed to a cathepsin L‐like enzyme through substrate specificity and inhibitors. The molecular weight is 37,000 to 39,000 as shown using gelatin‐containing SDS‐PAGE activity gels. At neutral pH the enzyme binds to vitellin, as demonstrated by gel filtration and PAGE under nondenaturing conditions. Acid proteinase activity at pH 5–6 is undetectable both with proteins and synthetic substrates, but is strongly increased after preincubation at pH 3–4. Activation at low pH could be important in the regulation of yolk degradation.
Yolk degradation in tick eggs: II. Evidence that cathepsin L‐like proteinase is stored as a latent, acid‐activable proenzyme
Authors: Fagotto François 
Published: February 2005

AbstractCathepsin L–like proteinase found in the eggs of the tick Ornithodoros moubata is latent during embryogenesis, but can be activated by acid treatment. In crude extracts as well as in partially purified fractions, activation requires reducing conditions and is inhibited by leupeptin, which indicates that it is mediated by a thiol proteinase, probably by the cathepsin L itself. Latency disappears in vivo at the time of the acute phase of yolk digestion, which takes place during late embryonic development and larval life. When egg cathepsin L is localized through its gelatinolytic activity on SDS‐PAGE, the activated enzyme migrates as lower Mr bands than the latent form. Disappearance of the higher Mr bands corresponding to the latent form is directly related to appearance of the lower Mr bands characteristic of the active one; transition from one pattern to the other and enzymatic activation are in perfect agreement with regard to kinetics and sensitivity to inhibitors. The same pattern change occurs in vivo, parallel to latency removal and intense yolk degradation. These results strongly suggest that egg cathepsin L is stored in the yolk as a proenzyme which is activated by partial proteolysis at low pH.
In vitro study of lipid metabolism in the mealworm larval fat body
Authors: Bahjou Ahmed , Gourdoux Lucienne , Moreau Robert , Puiroux Jacques , Dutrieu Janine 
Published: February 2005

AbstractLipid metabolism in Tenebrio larval fat body has been studied in vitro. Lipid release required the presence of diluted hemolymph in the incubation medium. This time‐dependent release of lipid was strongly stimulated in a dose‐dependent manner by Tenebrio corpora cardiaca (CC) extracts or synthetic adipokinetic hormone (AKH I). Furthermore, some glycerol was released when larval fat body was incubated without hemolymph, and this phenomenon was also dose dependent for added CC extracts. Lipid synthesis was estimated in vitro by following the incorporation of radioactivity from [6‐14C] glucose into fatty acids. Lipogenesis occurred in the absence of added carbohydrates in the medium, but it was stimulated by the addition of glucose, and especially trehalose (10 mg ml−1). Intestinal insulin‐like peptide (ILP) also stimulated in vitro lipogenesis in a dose‐dependent fashion. We conclude that lipolytic and lipogenetic activities of larval mealworm fat body in vitro are effectively under hormonal control.
Metabolism of ecdysteroids by a chitin‐synthesizing insect cell line
Authors: Ward Gordon B. , Beydon Philippe , LaFont Réne , Mayer Richard T. 
Published: February 2005

AbstractA chitin‐synthesizing cockroach cell line (UMBGE‐4) previously shown to secrete ecdysteroids was analyzed for its ability to metabolize potential precursors of ecdysone (e.g., 2‐deoxyecdysone, 2,22‐dideoxyecdysone, 2,22,25‐trideoxyecdysone, and cholesterol). All, except cholesterol, were actively metabolized by UMBGE‐4 cells. However, all but 2‐deoxyecdysone were converted to polar and hydrolyzable metabolites, and not to ecdysone. Labeling with cholesterol was unsuccessful. Labeling experiments with molting hormones, i.e., ecdysone and 20‐hydroxyecdysone, confirmed that this cell line can metabolize ecdysteroids and allowed identification of some of the products. Molting hormones were converted into acetate conjugates and polar conjugates which were often double‐conjugates, i.e., polar conjugates of acetate conjugates. Labeling experiments with ecdysone demonstrated that this cell line possesses a low ecdysone 20‐hydroxylase activity. The capacity of UMBGE‐2 cells, which do not synthesize chitin or ecdysteroids, was also examined. Neither ecdysone nor 20‐hydroxyecdysone was significantly metabolized by UMBGE‐2 cells. 2‐Deoxyecdysone and 2,22‐dideoxyecdysone were very slowly metabolized respectively to more polar compounds.
Action of RH 5849, a non‐steroidal ecdysteroid mimic, on Plodia interpunctella (Hübner) in vivo and in vitro
Authors: Silhacek Donald L. , Oberlander Herbert , Porcheron Patrick 
Published: February 2005

AbstractWe have examined the effects of RH 5849, a non‐steroidal ecdysteroid mimic, on the growth and development of Plodia interpunctella. When RH 5849 was administered in the diet, larval growth was inhibited in a dose‐dependent manner, while concentrations of 15 ppm and greater were highly toxic. However, the deleterious effects of RH 5849 could be prevented, except at very high concentrations of RH 5849, by the simultaneous administration of the juvenile hormone mimic methoprene. Larvae simultaneously treated with both hormone mimics continued to grow until they attained a size about three times normal. This growth was accompanied by at least one and sometimes two supernumerary molts, whereas, only an occasional supernumerary molt occurred in larvae treated with methoprene alone. In larvae undergoing super numerary molts, wing imaginal discs produced a tanned pupal cuticle, but did not evaginate. When wing discs were cultured in vitro, RH 5849 stimulated evagination and chitin synthesis at concentrations of 10 and 1 μM, respectively. Likewise, RH 5849 stimulated GlcNAc uptake and inhibited cellular proliferation in IAL‐PID2 cells at similar concentrations. These in vitro effects of RH 5849 also were produced by 20‐hydroxyecdysone, but at lower concentrations. We conclude that RH 5849 exhibits molting hormone activity in vivo as well as in vitro. However, the toxicological effects in P. interpuncetella result from action on feeding and growth, rather than molting. Thus, RH 5849 represents a new class of IGR, which will have impact on our understanding of endocrine regulation and open up new avenues for pest control.
Efficient transfection of mosquito cells is influenced by the temperature at which DNA‐calcium phosphate coprecipitates are prepared
Authors: Kjer Karl M. , Fallon Ann Marie 
Published: February 2005

AbstractTrnsient expression of a heat‐shock protein‐chloramphenicol acteyltrans‐Perase (hsp‐CAT) recombinant plasmid was used to define the parameters that influence transfection of cultured mosquito cells using DNA‐calcium phosphate coprecipitates. The efficiency of the calcium phosphate procedure was strongly influenced by the growth state of recipient cells, and by the temperature at which the coprecipitate was prepared. Under optimal conditions, which included formation of the DNA‐calcium phosphate coprecipitate at 50°C, transfection frequencies were up to tenfold higher than those obtained using the previously described polybrene procedure.
Demonstration of β‐N‐acetyl‐D‐glucosaminidase and β‐N‐acetyl‐D‐hexosaminidase in Drosophila Kc‐cells
Authors: Sommer Ulrich , Spindler Klaus‐Dieter 
Published: February 2005

AbstractKc‐cells from Drosophila melanogaster, grown under serum‐free conditions, produce two β‐hexosaminidases and secrete these enzymes into the medium. The two enzymes were separated by DEAE‐exchange chromatography. According to their substrate specificities one enzyme is a β‐N‐acetyl‐D‐glucosaminidase (E.C.3.2.1.30), the other one a β‐N‐acetyl‐D‐hexosaminidase (E.C.3.2.1.52). The β‐N‐acetyl‐D‐glucosaminidase is predominant in the medium, the β‐N‐acetyl‐D‐hexosaminidase within the cells. The Km values for the substrates pNP‐GlcNAc, pNP‐GalNAc, and (GlcNAc)2 are 0.8, 16.73, and 1.67 mM for the β‐N‐acetyl‐D‐glucosaminidase and 0.24, 0.44, and 0.2 mM for the β‐N‐acetyl‐D‐hexosaminidase. Both enzymes are inhibited by the products and the β‐N‐acetyl‐D‐glucosaminidase is also inhibited stereospecifically by the substrates pNP‐GlcNAc and (GlcNAc)2. Both enzymes are inhibited in a partial competitive way by acetamidolactones, the Kis being as low as 0.1 μM.
Lysozyme in the midgut of Manduca sexta during metamorphosis
Authors: Russell Virginia W. , Dunn Peter E. 
Published: February 2005

AbstractLow levels of lysozyme were found in the midgut epithelium of the tobacco hornworm, Manduca sexta, during the early part of the fifth larval stadium. This was observed in control insects as well as in bacterially challenged insects. No lysozyme was detected in the gut contents of either group of insects which were actively eating or in the early stages of metamorphosis. However, high levels of lysozyme activity were detected in homogenates of midgut tissue collected from insects later in the stadium. Immunocytochemical studies demonstrated that lysozyme accumulates in large apical vacuoles in regenerative cells of the midgut during the larval‐pupal molt. These cells, initially scattered basally throughout the larval midgut epithelium, multiply and form a continuous cell layer underneath the larval midgut cells. At the larval/pupal ecdysis the larval midgut epithelium is sloughed off and the regenerative cells, now forming the single cell layer of the midgut, release the contents of their vacuoles into the midgut lumen. This release results in high lysozyme activity in the lumen of the pupal midgut and is thought to confer protection from bacterial infection. This is the first indication that the lysozyme gene may be developmentally regulated in a specific tissue in the absence of a bacterial infection.
3‐oxoecdysteroid 3β‐reductase in various organs of the European corn borer, Ostrinia nubilalis (Hubner)
Authors: Gelman Dale B. , Demilo Albert B. , Thyagaraja Belgaum S. , Kelly Thomas J. , Masler Edward P. , Bell Robert A. , Borkovec Alexej B. 
Published: February 2005

AbstractExtracts of brains, subesophageal ganglia, Malpighian tubules, mandibular glands, proctodaea, salivary glands, testes, and fat body from mature fifth‐stage European corn borer larvae contain a 3‐oxoecdysteroid 3β‐reductase that converts 3‐dehydroecdysone to an RIA‐detectable ecdysteroid that has the same retention time (on HPLC and TLC) as ecdysone. Enzyme activity is destroyed by boiling, exposure to organic solvents, and treatment with trypsin. The reductase has a molecular weight in the range of 24–37 kD and is dependent upon the presence of NADPH for activity. Under the conditions utilized here, subesophageal ganglia, proctodaea, and brain extracts exhibited the highest specific activity; mandibular glands, testes, salivary glands, and Malpighian tubules had moderate specific activity; and fat body had the least. Based on total organ activity, however, fat body and salivary glands had the greates activity; testes, Malpighian tubules, mandibular glands, and proctodaeum had moderate activity; and brain and subesophageal ganglion had the least.
Stimulation of juvenile hormone biosynthesis by analogues of a Manduca sexta allatotropin: In vitro studies
Authors: Unni Balagopalan G. , Bhaskaran Govindan , Dahm Karl H. , Hayes Timothy K. 
Published: February 2005

AbstractTwo analogues of a Manduca sexta allatotropin (Mas‐AT) were synthesized. They correspond to the active fragment, amino acids 5–13, of the natural Mas‐AT with substitution of norleucine for methionine. ATANA has the structure Val‐Glu‐Nle‐Nle‐Thr‐Ala‐Arg‐Gly‐Phe‐NH2, ATAA is acetylated at the N‐terminus. Allatotropic potency was evaluated by measuring the in vitro rates of juvenile hormone (JH) biosynthesis in corpora allata (CA) of M. sexta.At a concentration of 20 nM, ATANA and ATAA increased JH production in day 0, day 1, and day 3 adult female CA by a factor of 3–8. Larval CA were not affected. These results correspond to activities reported for the natural Mas‐AT. ATANA did not stimulate pharate adult female CA to produce JH. Stimulation of female CA with ATANA was reversed when the CA were transferred to fresh medium while stimulation with ATAA under the same condition persisted.Exogenous farnesoate was converted to JH‐III at a rate exceeding the highest ATANA‐stimulated rate. ATANA in addition to farnesoate did not increase JH‐III production, but increased JH‐II production in addition to the already high production rate for JH‐III. It is inferred that Mas‐AT stimulates a rate‐limiting enzyme in the biosynthesis of farnesoate and its homologues but does not affect epoxidation and methylation.