The effect of digging on development of adult characters in blowflies Calliphora erythrocephala

Digging delays expansion after emergence of adult Calliphora. If flies are kept digging for 12 to 14 hr they lose the capacity to expand and, if they are then reared for 10 days, do not develop the normal adult corpus allatum, ovaries, and cuticle. In particular, ultrastructural examination of the resilin tendon of the pleurotergal muscle shows that development is arrested at a stage similar to that in the late pharate adult but the resilin is not cross-linked. It is suggested that bursicon release is irreversibly inhibited in flies that fail to expand normally.     

The effects of DOPA decarboxylase inhibitors on the permeability and ultrastructure of the larval cuticle of the Australian sheep blowfly, Lucilia cuprina

Larvae of Lucilia cuprina, fed toxic levels of α-methyl DOPA (or other DOPA decarboxylase inhibitors) during the first or second instar, die at the completion of the next moult, soon after exposing their new cuticles. In electron micrographs of newly synthesised cuticle from these treated larvae, the ultrastructure of the lipid-rich outer epicuticle layer appears to be abnormal. This newly formed cuticle of the treated larvae is apparently defective in its role as a water permeability barrier (compared with that of normal larvae), since it permits the free movement of water in both directions. Thus, treated larvae die most probably as a direct result of dehydration. Larvae fed toxic levels of α-methyl DOPA can be rescued from death by simultaneously adding N-acetyldopamine (the cuticular sclerotizing agent) to the food. The rescued larvae are apparently normal in all respects. This suggests that sclerotization is required for the formation of a normal outer epicuticle. Diflubenzuron, which is known to inhibit chitin deposition in the cuticles of a number of different species of insect, also apparently affects chitin deposition in the larval cuticle of L. cuprina. Thus, in electron micrographs of cuticle from larvae fed toxic levels of diflubenzuron the ultrastructure of the chitin-containing endocuticle layer appears to be abnormal.     

Identification and molecular analysis of a multigene family encoding calliphorin, the major larval serum protein of Calliphora vicina

A library of Calliphora vicina genomic DNA was constructed in the λEMBL3 vector and screened for recombinant phages containing chromosomal segments encoding calliphorin, the major larval serum protein (LSP) of Calliphora. A large series of recombinants hybridizing with in vitro labelled poly(A)⁺ RNA from Calliphora larval fat bodies and with specific probes derived from the LSP-1 genes of Drosophila melanogaster was isolated. Five of these phages, chosen at random, were shown by hybrid selection to retain calliphorin mRNA specifically. Eleven calliphorin mRNA-homologous regions were located on restriction maps of these phages by hybridization with 5' end-labelled poly(A)⁺ RNA from Calliphora larval fat bodies. Each phage contains at least two calliphorin genes arranged in direct repeat orientation and seperated by 3.5–5 kb intergenic regions. The genes display similar but not identical restriction patterns. Filter hybridization and heteroduplex analysis indicate that they share a detectable homology with the LSP-1β gene of D. melanogaster. Whole genome Southern analysis showed that these genes belong to a large family of closely related calliphorin genes which were found by in situ hybridization to polytene chromosomes of trichogen cells to be clustered in region 4a of chromosome 2 of Calliphora vicina.     

Tarsal attachment devices of the southern green stink bug Nezara viridula (Heteroptera: Pentatomidae)

Based on analyses with cryo‐scanning and transmission electron microscopy, the present study reports on the morphology and ultrastructure of the attachment structures of the green stinkbug Nezara viridula L. (Heteroptera: Pentatomidae), a cosmopolitan pest of different crops in most areas of the world. In addition, the presence and distribution of large proportions of the elastic protein resilin in these structures was revealed by confocal laser scanning microscopy. The attachment structures of each leg comprise two sclerotised claws, a pair of smooth flexible pulvilli and a hairy adhesive pad located at the ventral side of the basitarsus. No sexual dimorphism is evident. Contact areas of resting individuals on a smooth surface show that N. viridula creates contact to the substrate with the ventral surface of (a) the distal portions of the pulvilli, (b) the setae of the hairy adhesive pad, (c) the two paraempodia representing mechanosensory setae, and (d) the tips of the claws. Each pulvillus is a sac‐like structure formed by complex cuticular layers that vary in their structure and resilin content. The dorsal side consists of sclerotised chitinous material, while the ventral cuticle consists mainly of resilin and shows a very thin epicuticle and a thick exocuticle. The setae of the hairy adhesive pad are pointed and socketed. They exhibit a pronounced longitudinal gradient in the material composition, with large proportions of resilin being present in the setal tips. In most of these setae, especially in those of the distal‐most part of the pad, also a transverse gradient in the material composition is visible.     

Tyrosine and catecholamine metabolism in wild-type Drosophila melanogaster and a mutant, ebony

Microinjection of radioactive tyrosine, dopa, and dopamine into mature larvae of Drosophila revealed that the sclerotization pathway is similar but not identical to that in Calliphora: (a) tyrosine is converted to tyrosine-o-phosphate and not to dopa, and (b) the substrate N-acetyldopamine does not accumulate.Larvae of the mutant ebony appear to be similar to the wild type with respect to tyrosine, dopa, and dopamine utilization. About the time of eclosion, however, ebony has twice as much dopamine as normal. Some implications of this are discussed with reference to the mutant phenotype.     

In vitro study on humoral encapsulation of microfilariae: effects of diethyldithiocarbamate and dopachrome on the reaction

The effects of a phenoloxidase inhibitor, diethyldithiocarbamate, and an intermediate of the melanin biosynthetic pathway, dopachrome, on the humoral encapsulation of microfilariae were studied in vitro. Diethyldithiocarbamate inhibited the melanization but did not prevent the humoral encapsulation of microfilariae. In the presence of diethyldithiocarbamate in the in vitro system, transparent material in the form of numerous granules were deposited on the surface of the microfilariae and coalesced to form a consolidated transparent capsule around microfilariae. The thickness of transparent capsule was significantly greater than that of normal melanotic capsule. The transparent capsule material, which was probably the precursor of the melanotic capsule, was demonstrated histochemically as a protein-carbohydrate complex. The ultrastructure of transparent capsule showed that the transparent capsule material was very different from that of melanotic capsule material, being more flocculent and less granular in appearance. When dopachrome was concurrently present with the inhibitor in the in vitro encapsulation system, it failed to restore normal melanotic encapsulation. The data presented lead to the following conclusions: 1. The melanin biosynthetic pathway in the humoral encapsulation of microfilariae is similar to that found in the synthesis of mammalian melanin. 2. The humoral encapsulation of the microfilariae in vitro is a two-step process. The protein-carbohydrate complex is deposited on the surface of microfilariae. Then the tyrosine group of the complex is catalysed by phenoloxidase to melanin.     

Accumulation of Oxidized LDL in the Tendon Tissues of C57BL/6 or Apolipoprotein E Knock-Out Mice That Consume a High Fat Diet: Potential Impact on Tendon Health

ObjectiveClinical studies have suggested an association between dyslipidemia and tendon injuries or chronic tendon pain; the mechanisms underlying this association are not yet known. The objectives of this study were (1) to evaluate the impact of a high fat diet on the function of load-bearing tendons and on the distribution in tendons of oxidized low density lipoprotein (oxLDL), and (2) to examine the effect of oxLDL on tendon fibroblast proliferation and gene expression.MethodsGene expression (Mmp2, Tgfb1, Col1a1, Col3a1), fat content (Oil Red O staining), oxLDL levels (immunohistochemistry) and tendon biomechanical properties were examined in mice (C57Bl/6 or ApoE -/-) receiving a standard or a high fat diet. Human tendon fibroblast proliferation and gene expression (COL1A1, COL3A1, MMP2) were examined following oxLDL exposure.ResultsIn both types of mice (C57Bl/6 or ApoE -/-), consumption of a high fat diet led to a marked increase in oxLDL deposition in the load-bearing extracellular matrix of the tendon. The consumption of a high fat diet also reduced the failure stress and load of the patellar tendon in both mouse types, and increased Mmp2 expression. ApoE -/- mice exhibited more pronounced reductions in tendon function than wild-type mice, and decreased expression of Col1a1 compared to wild type mice. Human tendon fibroblasts responded to oxLDL by increasing their proliferation and their mRNA levels of MMP2, while decreasing their mRNA levels for COL1A1 and COL3A1.ConclusionThe consumption of a high fat diet resulted in deleterious changes in tendon function, and these changes may be explained in part by the effects of oxLDL, which induced a proliferative, matrix-degrading phenotype in human tenocytes.     

Studies on a Maize Mutant Sensitive to Low Temperature II. Chloroplast Structure, Development, and Physiology

In the Zea mays L. mutant M11 grown in the dark at 15°, the ultrastructure of the etioplast is abnormal. The pigment content of the etioplasts is reduced but the in vivo absorption characteristics suggest that the normal protochlorophyll (ide)-holochrome is present. The lowered synthetic ability of the etioplasts is not primarily due to a reduced complement of plastid ribosomes. The plastids of mutant M11 grown in the light at 15° contain little pigment, are markedly deficient in ribosomes and their ultrastructure is abnormal. In mutant M11 grown at 15°, an extreme sensitivity of the plastid membranes to light was observed.     

α-Actinin Is Required for the Proper Assembly of Z-Disk/Focal-Adhesion-Like Structures and for Efficient Locomotion in Caenorhabditis elegans

The actin binding protein α-actinin is a major component of focal adhesions found in vertebrate cells and of focal-adhesion-like structures found in the body wall muscle of the nematode Caenorhabditis elegans. To study its in vivo function in this genetic model system, we isolated a strain carrying a deletion of the single C. elegans α-actinin gene. We assessed the cytological organization of other C. elegans focal adhesion proteins and the ultrastructure of the mutant. The mutant does not have normal dense bodies, as observed by electron microscopy; however, these dense-body-like structures still contain the focal adhesion proteins integrin, talin, and vinculin, as observed by immunofluorescence microscopy. Actin is found in normal-appearing I-bands, but with abnormal accumulations near muscle cell membranes. Although swimming in water appeared grossly normal, use of automated methods for tracking the locomotion of individual worms revealed a defect in bending. We propose that the reduced motility of α-actinin null is due to abnormal dense bodies that are less able to transmit the forces generated by actin/myosin interactions.     

ORIENTATION BY OPPOSED BEAMS OF LIGHT

Computations of the effective angular inclination (H) of the photoreceptive surfaces of the two sides, based upon measurements of orientation angles under the action of beams of light directly opposed or crossing at right angles, show that with larvae of Calliphora and of Lucillia H declines as the total illumination decreases (i.e., as the angle of orientation away from the more intense light increases). H is greater with the two lights opposed at 180°; this may be due to the difference in refraction. For the more sharply pointed larvae of Lucillia, H is less than half as great as in Calliphora.     

Prothoracic glands in the regulation of ecdysone titres and metabolic fate of injected labelled ecdysone in Locusta migratoria

In the absence of the prothoracic glands, fifth instar larvae of Locusta migratoria contain no demonstrable quantities of ecdysone and ecdysterone (assayed together in the Calliphora bioassay), whereas normal larvae show a high peak of ecdysone activity. The metabolic fate of injected radiolabelled ecdysone is found to be very similar in prothoracectomized larvae to that of normal larvae (hydroxylation rate, dehydrogenation of ecdysone and ecdysterone, inactivation rate). However, in the absence of the prothoracic glands, the larvae excrete radiolabelled ecdysone in their faecal material at a rate which is considerably higher than that of normal insects of the same age. These results are discussed in view of the regulation of the ecdysone titres by the prothoracic glands in L. migratoria.     

Small peptides,a life-long store of amino acid in adult Drosophila and Calliphora

A sizable component of small peptide is probably an important store of amino acid in Calliphora and Drosophila. Quantitative amino acid analysis of the peptides in adult male Calliphora erythrocephala and Drosophila subobscura show that their composition is very similar. It is shown in Calliphora that the amount of peptide present in adults varies with age and feeding regime. Further, the peptide composition of the haemolymph indicates that the peptides are stored intracellularly. However, there is evidence which suggests that their hydrolysis takes place in the haemolymph, thus providing the whole fly with free amino acid and the haemolymph with osmotic stability.     

Modulation of hepatic lipidome by rhodioloside in high-fat diet fed apolipoprotein E knockout mice

BackgroundRhodioloside is a glucoside of tyrosol isolated from Rhodiola rosea. However, its regulating effect on hepatic dyslipidemia of atherogenic mice has rarely been studied.PurposeThe specific aims of current study included to clarify lipidomic perturbation in liver tissues of apolipoprotein E deficient (apoE^−/−) mice fed with high-fat diet, and to examine the effects of rhodioloside against atherosclerosis and dyslipidemia.Study DesignThe comparisons of hepatic lipidome were executed between wide type (WT) mice fed with normal diet (NDC) and apoE^−/− mice fed with high-fat diet (Model), WT mice fed with high-fat diet (HFDC) versus the model mice, as well as the model mice versus rhodioloside-treated atherosclerotic mice.MethodsUltra high performance liquid chromatography coupled with a Q exactive hybrid quadrupole-orbitrap mass spectrometry (UPLC-MS/MS) was employed to provide an unbiased and simultaneous measurement of individual lipid species in liver tissues.ResultsMultivariate statistical analysis derived from LC-MS spectra revealed that high-fat diet and apoE deficiency caused a series of disturbances on glyerolipid metabolism, glycerophospholipid metabolism and sphingolipid metabolism. Rhodioloside administration showed atheroprotective effects on the apoE^−/− mice with regulating the levels of 1 phosphatidylcholine, 2 phosphatidylserines, 5 alkyldiacylglycerols and 3 alkenyldiacylglycerols back to normal. In particular, PC (4:0/15:0) was positively associated with high-density lipoprotein cholesterol in blood, both of which could be ameliorated by rhodioloside.ConclusionOur results identified the abnormal hepatic lipids in atherosclerosis progression that could efficiently improved by rhodioloside. These lipids contributed to biological understanding of atherogenic dyslipidemia in liver and could also served as sensitive indicators for drug target screening.     

Kakapo,a Novel Cytoskeletal-associated Protein Is Essential for the Restricted Localization of the Neuregulin-like Factor,Vein, at the Muscle–Tendon Junction Site

In the Drosophila embryo, the correct association of muscles with their specific tendon cells is achieved through reciprocal interactions between these two distinct cell types. Tendon cell differentiation is initiated by activation of the EGF-receptor signaling pathway within these cells by Vein, a neuregulin-like factor secreted by the approaching myotube. Here, we describe the cloning and the molecular and genetic analyses of kakapo, a Drosophila gene, expressed in the tendons, that is essential for muscle-dependent tendon cell differentiation. Kakapo is a large intracellular protein and contains structural domains also found in cytoskeletal-related vertebrate proteins (including plakin, dystrophin, and Gas2 family members). kakapo mutant embryos exhibit abnormal muscle-dependent tendon cell differentiation. A major defect in the kakapo mutant tendon cells is the failure of Vein to be localized at the muscle–tendon junctional site; instead, Vein is dispersed and its levels are reduced. This may lead to aberrant differentiation of tendon cells and consequently to the kakapo mutant deranged somatic muscle phenotype.     

Functionally distinct tendons have different biomechanical,biochemical and histological responses to in vitro unloading

Tendons with different in vivo functions are known to have different baseline biomechanics, biochemistry and ultrastructure, and these can be affected by changes in loading. However it is not know whether different tendon types respond in the same, or different ways, to changes in loading.This study performed in vitro un-loading (stress deprivation) in culture on ovine medial extensor tendons (MET, a positional tendon), and superficial and deep digital flexor tendons (SDFTs and DDFTs, with energy-storing and intermediate functions respectively), for 21 days (n = 14 each). Tensile strength and elastic modulus were then measured, followed by biochemical assays for sulphated glycosaminoglycan (sGAG) and hydroxyproline content. Histological inspection for cell morphology, cell density and collagen alignment was also performed.The positional tendon (MET) had a significant reduction (∼50%) in modulus and strength (P < 0.001) after in vitro stress-deprivation, however there were no significant effects on the energy-storing tendons (SDFT and DDFT). In contrast, sGAG was not affected in the MET, but was reduced in the SDFT and DDFT (P < 0.001). All tendons lost compactness and collagen organisation, and had reduced cell density, but these were more rapid in the MET than the SDFT and DDFT.These results suggest that different tendon types respond to identical stimuli in different ways, thus; (i) the results from an experiment in one tendon type may not be as applicable to other tendon types as previously thought, (ii) positional tendons may be particularly vulnerable to clinical stress-deprivation, and (iii) graft tendon source may affect the biological response to loading in ligament and tendon reconstruction.     

Abnormal spore morphology and wall ultrastructure in Anemia tomentosa var. anthriscifolia and A. tomentosa var. tomentosa (Anemiaceae)

The spores of Anemia tomentosa var. anthriscifolia and A. tomentosa var. tomentosa were studied focusing the attention on their abnormalities. The study was based on fresh and herbarium material and the spores were examined with light, scanning and transmission electron microscopy. Normal, abnormal and abortive spores were observed in both taxa. The normal spores were trilete, triangular in polar view, and the ornamentation consisted of parallel ridges separated by narrow and smooth grooves. The spores were observed in monads, dyads, triads and tetrads. The abnormal spores were monolete, trilete, tetralete or alete with great variations in size. In fact, some spores were almost double the size of the normal ones. Some differences were also found in the ornamentation of the spores. Aborted and not completely developed spores were also observed in the specimens. The wall ultrastructure of the taxa was studied for the first time. The exospore was two-layered with numerous cavities inside its structure, and the perispore was also two-layered. The results revealed that the sporoderm ultrastructure of both normal and abnormal spores of the taxa analyzed was very similar.     

Predation on the slug Deroceras reticulatum by the carabid beetles Pterostichus madidus and Nebria brevicollis in the presence of alternative prey

1 Slugs are important pests in many agricultural crops and potential biological control agents are being studied as an alternative to molluscicides. Carabid beetles may be able to reduce slug populations, but their role as control agents may be influenced by the presence of alternative prey. 2 Attacks on the pest slug Deroceras reticulatum (Müller) by the carabid beetles Pterostichus madidus (Fabricius) and Nebria brevicollis (Fabricius) were investigated in the presence of alternative prey (earthworms and Calliphora fly larvae). Consumption of slug eggs and aphids was also investigated. 3 All five prey types were consumed to varying degrees during the experiments. Both beetle species showed a significant preference for Calliphora larvae over slugs. Pterostichus madidus showed a significant preference for earthworms over slugs. No preference was shown between earthworms or Calliphora larvae by P. madidus females or N. brevicollis. However, P. madidus males showed a significant preference for Calliphora larvae over worms. Pterostichus madidus showed no preference between slug eggs and aphids; N. brevicollis showed a significant preference for aphids over slug eggs. 4 The results from this study indicate that generalist beetles will often attack other prey in preferences to adult slugs. Slugs may not be preferred because of their mucus. Other prey items occur frequently in arable soils and generalist carabids may ignore slugs altogether and may only feed on them when slug density is high or other prey are unavailable.     

Feuerborn's hypothesis of hypopygial circumversion in schizophoran Diptera: A repetition and reappraisal of Schräder's (1927) studies

Schräder's (1927) investigations on the hypopygial circumversion in Calliphora (Diptera : Calliphoridae) pupae have been repeated with improved techniques and more efficient control and Feuerborn's (1922) hypothesis of hypopygial circumversion has been disproved. The development of the male reproductive organs is described. Serious defects and ambiguities in Schräder's (1927) techniques invalidate his claims for hypopygial circumversion in pupal Calliphora. Salzer's (1968) claims of a double chiasmata in the hypopygial nervous system have been modified. The available evidence shows that no rotation of the hypopygial segments occurs in either the pupal or the pharate adult stages of Calliphora vicinia. It is suggested that the unique schizophoran ductus-hindgut relationship originated as a result of the coiling of the larval and adult alimentary canals, causing an internal clockwise (seen anteriorly) displacement of the organs concerned. The causes of the observed hypopygial sexual differences are discussed.