Two Splice Isoforms of Leptinotarsa Ecdysis Triggering Hormone Receptor Have Distinct Roles in Larva-Pupa Transition

Insect ecdysis triggering hormone (ETH) receptors (ETHRs) are rhodopsin-like G protein-coupled receptors. Upon binding its ligand ETH, ETHR initiates a precisely programed ecdysis behavior series and physiological events. In Drosophila melanogaster, the ethr gene produces two functionally distinct splicing isoforms, ethra and ethrb. ETH/ETHRA activates eclosion hormone (EH), kinin, crustacean cardioactive peptide (CCAP), and bursicon (burs and pburs) neurons, among others, in a rigid order, to elicit the behavioral sequences and physiological actions for ecdysis at all developmental stages, whereas ETH/ETHRB is required at both pupal and adult ecdysis. However, the role of ETHRB in regulation of molting has not been clarified in any non-drosophila insects. In the present paper, we found that 20-hydroxyecdysone (20E) signaling triggers the expression of both ethra and ethrb in a Coleopteran insect pest, the Colorado potato beetle Leptinotarsa decemlineata. RNA interference (RNAi) was performed using double-stranded RNAs (dsRNAs) targeting the common (dsethr) or isoform-specific (dsethra, dsethrb) regions of ethr. RNAi of dsethr, dsethra, or dsethrb by the final-instar larvae arrested larva development. The arrest was not rescued by feeding 20E. All the ethra depleted larvae stopped development at prepupae stage; the body cavity was expanded by a large amount of liquid. Comparably, more than 80% of the ethrb RNAi larvae developmentally halted at the prepupae stage. The remaining Ldethrb hypomorphs became pupae, with blackened wings and highly-expressed burs, pburs and four melanin biosynthesis genes. Therefore, ETHRA and ETHRB play isoform-specific roles in regulation of ecdysis during larva-pupa transition in L. decemlineata.

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Transovarial Transmission of Rickettsia spp. and Organ-Specific Infection of the Whitefly Bemisia tabaci

Applied and Environmental Microbiology ◽

10.1128/aem.01184-12 ◽

2012 ◽

Vol 78 (16) ◽

pp. 5565-5574 ◽

Cited By ~ 42

Author(s):

Marina Brumin ◽

Maggie Levy ◽

Murad Ghanim

Keyword(s):

Vertical Transmission ◽

Bemisia Tabaci ◽

Developmental Stages ◽

Close Association ◽

Insect Pest ◽

Symbiotic Bacterium ◽

Body Cavity ◽

The Body ◽

Bacterial Cells ◽

Content Type

ABSTRACTThe whiteflyBemisia tabaciis a cosmopolitan insect pest that harborsPortiera aleyrodidarum, the primary obligatory symbiotic bacterium, and several facultative secondary symbionts. Secondary symbionts inB. tabaciare generally associated with the bacteriome, ensuring their vertical transmission; however,Rickettsiais an exception and occupies most of the body cavity, except the bacteriome. The mode ofRickettsiatransfer between generations and its subcellular localization in insect organs have not been investigated. Using electron and fluorescence microscopy, we show thatRickettsiainfects the digestive, salivary, and reproductive organs of the insect; however, it was not observed in the bacteriome.Rickettsiainvades the oocytes during early developmental stages and resides in follicular cells and cytoplasm; it is mostly excluded when the egg matures; however, some bacterial cells remain in the egg, ensuring their transfer to subsequent generations.Rickettsiawas localized to testicles and the spermatheca, suggesting a horizontal transfer between males and females during mating. The bacterium was further observed at large amounts in midgut cells, concentrating in vacuole-like structures, and was located in the hemolymph, specifically at exceptionally large amounts around bacteriocytes and in fat bodies. Organs further infected byRickettsiaincluded the primary salivary glands and stylets, sites of possible secretion of the bacterium outside the whitefly body. The close association betweenRickettsiaand theB. tabacidigestive system might be important for digestive purposes. The vertical transmission ofRickettsiato subsequent generations occurs via the oocyte and not, like other secondary symbionts, the bacteriome.

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The development of Psychodiella sergenti (Apicomplexa: Eugregarinorida) in Phlebotomus sergenti (Diptera: Psychodidae)

Parasitology ◽

10.1017/s0031182011002411 ◽

2012 ◽

Vol 139 (6) ◽

pp. 726-734 ◽

Cited By ~ 5

Author(s):

LUCIE LANTOVA ◽

PETR VOLF

Keyword(s):

Electron Microscopy ◽

Developmental Stages ◽

Periodic Acid ◽

Body Cavity ◽

The Body ◽

Sand Fly ◽

Intestinal Lumen ◽

Periodic Acid Schiff ◽

Phlebotomus Sergenti ◽

Schiff Reaction

SUMMARYPsychodiella sergenti is a recently described specific pathogen of the sand fly Phlebotomus sergenti, the main vector of Leishmania tropica. The aim of this study was to examine the life cycle of Ps. sergenti in various developmental stages of the sand fly host. The microscopical methods used include scanning electron microscopy, transmission electron microscopy and light microscopy of native preparations and histological sections stained with periodic acid-Schiff reaction. Psychodiella sergenti oocysts were observed on the chorion of sand fly eggs. In 1st instar larvae, sporozoites were located in the ectoperitrophic space of the intestine. No intracellular stages were found. In 4th instar larvae, Ps. sergenti was mostly located in the ectoperitrophic space of the intestine of the larvae before defecation and in the intestinal lumen of the larvae after defecation. In adults, the parasite was recorded in the body cavity, where the sexual development was triggered by a bloodmeal intake. Psychodiella sergenti has several unique features. It develops sexually exclusively in sand fly females that took a bloodmeal, and its sporozoites bear a distinctive conoid (about 700 nm long), which is more than 4 times longer than conoids of the mosquito gregarines.

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Bacillus thuringiensis Spores and Cry3A Toxins Act Synergistically to Expedite Colorado Potato Beetle Mortality

Toxins ◽

10.3390/toxins13110746 ◽

2021 ◽

Vol 13 (11) ◽

pp. 746

Author(s):

Ivan M. Dubovskiy ◽

Ekaterina V. Grizanova ◽

Daria Tereshchenko ◽

Tatiana I. Krytsyna ◽

Tatyana Alikina ◽

...

Keyword(s):

Bacillus Thuringiensis ◽

Colorado Potato Beetle ◽

Insect Pest ◽

Microbial Community Composition ◽

The Body ◽

Post Inoculation ◽

Mrna Levels ◽

Metabolic Derangement ◽

Oxidation Stress ◽

Potato Beetle

The insect integument (exoskeleton) is an effective physiochemical barrier that limits disease-causing agents to a few portals of entry, including the gastrointestinal and reproductive tracts. The bacterial biopesticide Bacillus thuringiensis (Bt) enters the insect host via the mouth and must thwart gut-based defences to make its way into the body cavity (haemocoel) and establish infection. We sought to uncover the main antibacterial defences of the midgut and the pathophysiological features of Bt in a notable insect pest, the Colorado potato beetle Leptinotarsa decemlineata (CPB). Exposing the beetles to both Bt spores and their Cry3A toxins (crystalline δ-endotoxins) via oral inoculation led to higher mortality levels when compared to either spores or Cry3A toxins alone. Within 12 h post-exposure, Cry3A toxins caused a 1.5-fold increase in the levels of reactive oxygen species (ROS) and malondialdehyde (lipid peroxidation) within the midgut – key indicators of tissue damage. When Cry3A toxins are combined with spores, gross redox imbalance and ‘oxidation stress’ is apparent in beetle larvae. The insect detoxification system is activated when Bt spores and Cry3A toxins are administered alone or in combination to mitigate toxicosis, in addition to elevated mRNA levels of candidate defence genes (pattern-recognition receptor, stress-regulation, serine proteases, and prosaposin-like protein). The presence of bacterial spores and/or Cry3A toxins coincides with subtle changes in microbial community composition of the midgut, such as decreased Pseudomonas abundance at 48 h post inoculation. Both Bt spores and Cry3A toxins have negative impacts on larval health, and when combined, likely cause metabolic derangement, due to multiple tissue targets being compromised.

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The development ofMoniezia expansain the intermediate host

Parasitology ◽

10.1017/s0031182000026032 ◽

1938 ◽

Vol 30 (4) ◽

pp. 491-501 ◽

Cited By ~ 17

Author(s):

Horace W. Stunkard

Keyword(s):

Intermediate Host ◽

Developmental Stages ◽

Body Cavity ◽

The Body ◽

Intermediate Hosts

When eggs ofMonieza expansaare fed to galumnid mites, the onchospheres emerge in the intestine and migrate to the body cavity. Here they undergo metamorphosis and develop into cysticercoids. The dissection of mites, at various intervals after exposure, has yielded a successive series of developmental stages. Protocols of the experiments and photographs of living larvae are presented. These results demonstrate that mites serve as intermediate hosts ofMoniezia, and probably also of other anoplocephaline cestodes.

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Myiasis in Bufo regularis caused by a Tabanid Larva

Parasitology ◽

10.1017/s0031182000019934 ◽

1924 ◽

Vol 16 (1) ◽

pp. 111-112

Author(s):

Edward Hindle

Keyword(s):

Fibrous Tissue ◽

Dorsal Surface ◽

Body Cavity ◽

The Body ◽

Careful Examination ◽

Large Female ◽

Considerable Time ◽

Ventral Region ◽

Cylindrical Structure ◽

The Right

In December, 1922, whilst dissecting a large female example of Bufo regularis, one of my students noticed a cylindrical structure extending along the ventral region of the body-cavity. A careful examination showed that this structure consisted of an elongated sac-like diverticulum of the right lung, containing an almost full-grown specimen of a dipterous larva, which could be seen through the membraneous wall of the diverticulum. The base of the latter, in addition to its point of origin from the lung, was also connected to the dorsal surface of the liver by strands of fibrous tissue, suggesting that the growth had been in existence some considerable time in order to cause such adhesions. Posteriorly, the diverticulum hung freely in the body cavity and extended to the extreme hinder end. Its dimensions were 5·5 cm. in length, by 0·5 cm. in diameter, but tapering towards each extremity.

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Seasonal occurrence of some larval stages of endoparasites in three cyprinids from the Nwanedi-Luphephe dams, the Limpopo River System, South Africa

Helminthologia ◽

10.1515/helmin-2015-0037 ◽

2015 ◽

Vol 52 (3) ◽

pp. 229-235 ◽

Cited By ~ 2

Author(s):

E. M. Mbokane ◽

J. Theron ◽

W. J. Luus-Powell

Keyword(s):

Developmental Stages ◽

River System ◽

Intestinal Wall ◽

The Body ◽

Seasonal Occurrence ◽

Seasonal Fluctuations ◽

Metazoan Parasites ◽

Larval Stages ◽

Parasite Communities ◽

Third Stage

Abstract This study provides information on seasonal occurrence of developmental stages of endoparasites infecting three cyprinids in the Nwanedi-Luphephe dams, Limpopo River System. Labeobarbus marequensis (Smith, 1841), Barbus trimaculatus Peters, 1852 and Barbus radiatus Peters, 1853 were investigated seasonally from January 2008 to October 2008. The following larvae of metazoan parasites were collected: Diplostomum sp. from the eyes of L. marequensis and B. trimaculatus; Ornithodiplostomum sp. from the gills of B. trimaculatus; Posthodiplostomum sp. from muscle, skin and fins of B. trimaculatus and B. radiatus; third-stage Contracaecum larvae (L3) from the mesentery fats and on the liver lobes of L. marequensis and B. trimaculatus and gryporynchid cestode larvae from the outer intestinal wall of B. radiatus. All the flukes encountered were metacercariae. Diplostomum sp. and Contracaecum sp. dominated the parasite communities. Their prevalence exhibited seasonal fluctuations with maxima in summer. Factors likely to influence fish infection such as the body size of fish and their condition factors were also briefly considered in this study.

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ENCAPSULATION OF RHABDITOID NEMATODES IN MOSQUITOES

Canadian Journal of Zoology ◽

10.1139/z62-103 ◽

1962 ◽

Vol 40 (7) ◽

pp. 1269-1275 ◽

Cited By ~ 41

Author(s):

Joan F. Bronskill

Keyword(s):

Aedes Aegypti ◽

Endemic Species ◽

Body Cavity ◽

Fourth Instar ◽

The Body ◽

Histological Structure ◽

Adult Tissue ◽

Defence Reaction ◽

Blood Sinus

In third and fourth instar larvae of Aedes aegypti (L.), juveniles of the rhabditoid, DD136, penetrate the blood sinus and cardial epithelium of the proventriculus to enter the body cavity of the host, where they complete their development. By 5 hours, a thick capsule developed about many of the ensheathed immature adults of DD136 within the body cavity of A. aegypti larvae. This rapid defence reaction of the mosquito to DD136, which has both a melanin and a cellular manifestation, occurs both in the exotic mosquito A. aegypti and in the two endemic species tested, Aedes stimulans (Walker) and Aedes trichurus (Dyar). The resistance of A. stimulans to an endemic rhabditoid, possibly of the Diplogasteridae, is also similar. The histological structure of the capsule is not affected during metamorphosis in A. aegypti; however, during histogenesis of adult tissue displacement and (or) distortion of some tissues and organs may be caused by the presence of the capsule within the host's body cavity. The activity of the adult A. aegypti is normal when this distortion or displacement is minor. Though usually encapsulated DD136 are retained within the body cavity of A. aegypti during metamorphosis, sometimes they are partially or completely expelled from the host's body cavity at the time of molting.

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Developmental stages in the Digenea

Parasitology ◽

10.1017/s0031182000067937 ◽

1964 ◽

Vol 54 (2) ◽

pp. 295-312 ◽

Cited By ~ 6

Author(s):

Elon E. Byrd ◽

William P. Maples

Keyword(s):

Body Wall ◽

Developmental Stages ◽

Snail Host ◽

The Body ◽

Body Movements ◽

Hatching Enzyme ◽

Apical Papilla ◽

Short Time ◽

Membranous Body ◽

Egg Capsule

The naturally oviposited egg of Dasymetra conferta is fully embryonated and it hatches only after it is ingested by the snail host, Physa spp.Hatching appears to be in response to some stimulus supplied by the living snail. The stimulus causes the larva to exercise a characteristic series of body movements and to liberate a granular sustance (hatching enzyme) from the larger pair of its cephalic glands. This enzyme reacts with the vitelline fluid to create pressure within the egg capsule, and with the cementum of the operculum, so that it may be lifted away. The larva's escape from the shell, therefore, is due to a combination of pressure and body movements.The hatched larva has a membranous body wall, supporting six epidermal plates, an apical papilla, two penetration glands and a central matrix (the presumptive brood mass).It lives for about an hour within the snail and during this time there is a reorganization of the central matrix which terminates in the formation of an 8-nucleated syncytial brood mass.The miracidial ‘case’, consisting of the body wall and the epidermal plates, ultimately ruptures to liberate the brood mass. Once the brood mass is free it penetrates through the gut wall in an incredibly short time.

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Studies on Tapeworm Physiology

Journal of Experimental Biology ◽

10.1242/jeb.26.1.1 ◽

1949 ◽

Vol 26 (1) ◽

pp. 1-15

Author(s):

J. D. SMYTH

Keyword(s):

Bacterial Infections ◽

Detrimental Effect ◽

Horse Serum ◽

Body Cavity ◽

The Body ◽

Nutrient Media ◽

Medium Strength ◽

By Products ◽

Histochemical Examination

1. Plerocercoid larvae of the pseudophyllidean cestode Ligula intestinalis from the body cavity of roach, were cultured in vitro at 40°C. in a variety of saline and nutrient media. About 65% of such cultures were aseptic. 2. During cultivation, larvae produced acid by-products (unidentified) and the pH fell rapidly. 3. The presence of these acid by-products slowed down development, or, if present in sufficient quantity, caused death. 4. In order to obtain development in nutrient media in a period (3 days) comparable to that required in a bird (the normal host) it was necessary to renew the medium 24-hourly. 5. 6% of the eggs produced from a worm cultured in horse serum were fertile. Fertile eggs were never obtained from larvae cultured in any other media. 6. Certain bacterial infections had no apparent detrimental effect on development, but others were toxic. 7. Some larvae underwent development in non-nutrient medium (¾ strength Locke's solution). The exact conditions under which this occurred was not determined. 8. Fragments (3 cm. long), of larvae or larvae with either scolex or posterior half removed, underwent development to the stage of oviposition in nutrient media. 9. Histochemical examination revealed that the plerocercoid larvae were almost fat-free. During cultivation, very large quantities of cytoplasmic fat were produced the quantity being proportional to the duration of cultivation. Fat was produced even under starvation conditions (i.e. during cultivation in saline) and can be considered a metabolic by-product. 10. The fresh plerocercoid contained great quantities of glycogen in the parenchyma and muscle regions. After cultivation in nutrient or saline media, considerable quantities were still present.

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The occurrence of Contracaecum sp. larvae (Nematoda : Anisakidae) in the catfishClarias gariepinus (Burchell) from Lake Chivero, Zimbabwe

Onderstepoort Journal of Veterinary Research ◽

10.4102/ojvr.v71i1.283 ◽

2004 ◽

Vol 71 (1) ◽

Cited By ~ 15

Author(s):

M. Barson

Keyword(s):

Significant Relationship ◽

Condition Factor ◽

Clarias Gariepinus ◽

Parasite Prevalence ◽

Body Cavity ◽

The Body ◽

Nematode Parasites ◽

Significant Difference ◽

Third Stage ◽

Males And Females

Clarias gariepinus were collected from Lake Chivero, Zimbabwe, and examined for nematode parasites from November 2000 to May 2002. Of the 202 specimens collected, 42.6 % were infected with third-stage larvae of Contracaecum sp. in the body cavity. The intensity of the infection was 1-7 worms per fish (mean intensity = 2.2). Seasonal variation in the prevalence of the parasite was not obvious and there was no significant difference in the prevalence of infection between males and females (c2 = 2.228; P > 0.05). No significant relationship between host size and prevalence was established. There was also no significant relationship between intensity and the body condition factor (r = 0.11; P > 0.05). The low parasite prevalence may have been caused by the disruption of the infection cycle since piscivorous birds, which are the final hosts of the parasite, do not feed on C. gariepinus in Lake Chivero.

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