Vitellogenin and Ecdysteroid Titers in Ixodes scapularis during Vitellogenesis

Am, James; Xx, Zhu; Jh, Oliver

doi:10.2307/3284224

Cited by 26 publications

(6 citation statements)

References 20 publications

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“…azedarach , showing that this plant interferes with the neuroendocrine system of insects (Schmidt et al ., 1998). Although the physiology of reproduction in ticks is not as well understood as in insects, the participation of ecdysteroids in this process has been demonstrated (James et al ., 1997). Therefore, the reproductive effects observed on B. microplus females are probably due to alterations on the neuroendocrine system of the tick.…”

Section: Means ± Sd Of Mortality Rates Of Boophilus Microplus Larvae mentioning

confidence: 99%

In vitro efficacy of extracts of Melia azedarach against the tick Boophilus microplus

Borges

Ferri²,

Silva

et al. 2003

Medical Vet Entomology

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The efficacy of ripe fruit extracts of Melia azedarach L. (Rutales: Meliaceae) was evaluated against the tick, Boophilus microplus (Canestrini) (Acari: Ixodidae). Ripe fruits of M. azedarach dried and powdered were extracted by Soxhlet apparatus successively using hexane, CHCl3 and 96% aqueous ethanol. Larvae and engorged females were immersed in decreasing concentrations from 0.25% to 0.015% of each extract. The mortality of larvae was evaluated 24, 72 and 168 h after treatment. The effectiveness of treatment against engorged females was assessed by measuring egg production. All tested extracts caused mortality of B. microplus larvae, with higher mortality rates observed in CHCl3 (100%) and hexanic extract (98%) than in ethanolic extract (50%) 168 h after treatment. The mortality was dependent on concentration and on time after treatment. Similarly hexanic and CHCl3 extracts showed higher effectiveness (varying from 14% to 100%) against B. microplus engorged females than ethanolic extract (varying from 0% to 46%). Melia azedarach extracts did not kill the adult females, but inhibited partially or totally egg production and embryogenesis. These results show that the less polar the extract of M. azedarach ripe fruits the more its effectiveness against larvae and engorged females of B. microplus. This plant may therefore be useful in the control of resistant B. microplus populations.

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Section: Means ± Sd Of Mortality Rates Of Boophilus Microplus Larvae mentioning

confidence: 99%

In vitro efficacy of extracts of Melia azedarach against the tick Boophilus microplus

Borges

Ferri²,

Silva

et al. 2003

Medical Vet Entomology

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“…Glucose is the primary carbohydrate constituent in mammalian blood [26], [27] and B. burgdorferi can use glucose to support growth [28]. Ticks rely on a high concentration of carbohydrates and other nutrients available in the blood meal for molting and successful oogenesis [29], [30]. During feeding, ticks create a peritrophic matrix above the epithelial cell layer, which serves both as a compartment to trap the blood meal and as a barrier to prevent invasion by microorganisms that accompany the blood meal.…”

Section: Introductionmentioning

confidence: 99%

Borrelia burgdorferi Requires Glycerol for Maximum Fitness During The Tick Phase of the Enzootic Cycle

et al. 2011

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Borrelia burgdorferi, the spirochetal agent of Lyme disease, is a vector-borne pathogen that cycles between a mammalian host and tick vector. This complex life cycle requires that the spirochete modulate its gene expression program to facilitate growth and maintenance in these diverse milieus. B. burgdorferi contains an operon that is predicted to encode proteins that would mediate the uptake and conversion of glycerol to dihydroxyacetone phosphate. Previous studies indicated that expression of the operon is elevated at 23°C and is repressed in the presence of the alternative sigma factor RpoS, suggesting that glycerol utilization may play an important role during the tick phase. This possibility was further explored in the current study by expression analysis and mutagenesis of glpD, a gene predicted to encode glycerol 3-phosphate dehydrogenase. Transcript levels for glpD were significantly lower in mouse joints relative to their levels in ticks. Expression of GlpD protein was repressed in an RpoS-dependent manner during growth of spirochetes within dialysis membrane chambers implanted in rat peritoneal cavities. In medium supplemented with glycerol as the principal carbohydrate, wild-type B. burgdorferi grew to a significantly higher cell density than glpD mutant spirochetes during growth in vitro at 25°C. glpD mutant spirochetes were fully infectious in mice by either needle or tick inoculation. In contrast, glpD mutants grew to significantly lower densities than wild-type B. burgdorferi in nymphal ticks and displayed a replication defect in feeding nymphs. The findings suggest that B. burgdorferi undergoes a switch in carbohydrate utilization during the mammal to tick transition. Further, the results demonstrate that the ability to utilize glycerol as a carbohydrate source for glycolysis during the tick phase of the infectious cycle is critical for maximal B. burgdorferi fitness.

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“…Other studies have identified ecdysteroids in ticks and mites using various detection methods. Ecdysone and 20E were identified by high performance liquid chromatography (HPLC)-radioimmunoassay in the hard tick Ixodes scapularis during the vitellogenic period (James et al, 1997). They were also identified in the soft tick Ornithodoros parkeri and the final hydroxylation from ecdysone to 20HE occurred in epidermal tissues (Zhu et al, 1991).…”

Section: Introductionmentioning

confidence: 99%

Three Halloween genes from the Varroa mite,Varroa destructor(Anderson & Trueman) and their expression during reproduction

Cabrera

Shirk

Evans

et al. 2014

Insect Molecular Biology

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The ecdysteroid biosynthetic pathway involves sequential enzymatic hydroxylations by a group of enzymes collectively known as Halloween gene proteins. Complete sequences for three Halloween genes, spook (Vdspo), disembodied (Vddib) and shade (Vdshd), were identified in varroa mites and sequenced. Phylogenetic analyses of predicted amino acid sequences for Halloween orthologues showed that the acarine orthologues were distantly associated with insect and crustacean clades indicating that acarine genes had more ancestral characters. The lack of orthologues or pseudogenes for remaining genes suggests these pathway elements had not evolved in ancestral arthropods. Vdspo transcript levels were highest in gut tissues, while Vddib transcript levels were highest in ovary-lyrate organs. In contrast, Vdshd transcript levels were lower overall but present in both gut and ovary-lyrate organs. All three transcripts were present in eggs removed from gravid female mites. A brood cell invasion assay was developed for acquiring synchronously staged mites. Mites within 4 h of entering a brood cell had transcript levels of all three that were not significantly different from mites on adult bees. These analyses suggest that varroa mites may be capable of modifying 7-dehydro-cholesterol precursor and hydroxylations of other steroid precursors, but whether the mites directly produce ecdysteroid precursors and products remains undetermined.

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Vitellogenin and Ecdysteroid Titers in Ixodes scapularis during Vitellogenesis

Cited by 26 publications

References 20 publications

In vitro efficacy of extracts of Melia azedarach against the tick Boophilus microplus

In vitro efficacy of extracts of Melia azedarach against the tick Boophilus microplus

Borrelia burgdorferi Requires Glycerol for Maximum Fitness During The Tick Phase of the Enzootic Cycle

Three Halloween genes from the Varroa mite,Varroa destructor(Anderson & Trueman) and their expression during reproduction

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