A physiological and biochemical model for digestion in the ectoparasitic mite, Psoroptes ovis (Acari: Psoroptidae)

Hamilton, Katherine; Nisbet, Alasdair J.; Lehane, Michael J.; Taylor, Mike; Billingsley, Peter F.

doi:10.1016/s0020-7519(03)00089-4

Cited by 46 publications

(51 citation statements)

References 108 publications

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“…Apesar de hábito alimentar não invasivo, B. ovis estimula resposta imunológica, a qual tem impacto sobre a população de piolho no hospedeiro. Alguns ovinos não se tornam infestados ou não apresentam infestação pesada mesmo quando desafiados repetidamente, o que reforça as evidências de que a resposta imunológica desempenha papel na regulação da população de piolhos (James, 1999).…”

Section: Patogenia E Sinais Clínicosunclassified

“…Vários membros da ordem Astigmata caracterizam--se por ingerirem alimento sólido, entretanto, Psoroptes é adaptado para ingerir alimento líquido, que consiste principalmente de exsudato seroso oriundo do hospedeiro. Conforme os ácaros deslocam-se sobre a superfície corporal, material antigênico, alergênico e enzimaticamente ativo é depositado, causando respos-ta inflamatória na pele, que resulta em lesões com a liberação de exsudato seroso e eritrócitos, material utilizado pelos ácaros em sua alimentação (Hamilton et al, 2003). Portanto, essa resposta imunoinflamatória desencadeada pelos produtos dos ácaros é a principal causa de prurido e alterações patológicas.…”

Section: Patogenia E Sinais Clínicosunclassified

“…Componentes da saliva podem também iniciar ou exacerbar a resposta inflamatória e o extravazamento de exsudato seroso. As alterações patológicas podem ser exacerbadas pela presença de bactérias que se desenvolvem nas lesões, e a natureza da sarna pode ser determinada em parte pelas espécies de bactérias presentes (Hamilton et al, 2003).…”

Section: Patogenia E Sinais Clínicosunclassified

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Os parasitas de ovinos

Amarante¹,

Ragozo²,

Silva³

2014

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Section: Patogenia E Sinais Clínicosunclassified

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Os parasitas de ovinos

Amarante¹,

Ragozo²,

Silva³

2014

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“…Aspartic proteinases, such as cathepsin D, have been implicated in blood meal digestion of ectoparasitic mites and ticks (Boldbaatar et al 2006;Hamilton et al 2003). A first indication for the presence of aspartic proteinases in the gastric fluid of European lobsters was provided by Navarrete del Toro et al (2006).…”

Section: General Features Of Cathepsinsmentioning

confidence: 99%

Aspartic Cathepsin D Endopeptidase Contributes to Extracellular Digestion in Clawed Lobsters Homarus americanus and Homarus gammarus

et al. 2010

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Acid digestive proteinases were studied in the gastric fluids of two species of clawed lobster (Homarus americanus and Homarus gammarus). An active protein was identified in both species as aspartic proteinase by specific inhibition with pepstatin A. It was confirmed as cathepsin D by mass mapping, N-terminal, and full-length cDNA sequencing. Both lobster species transcribed two cathepsin D mRNAs: cathepsin D1 and cathepsin D2. Cathepsin D1 mRNA was detected only in the midgut gland, suggesting its function as a digestive enzyme. Cathepsin D2 mRNA was found in the midgut gland, gonads, and muscle. The deduced amino acid sequence of cathepsin D1 and cathepsin D2 possesses two catalytic DTG active-site motifs, the hallmark of aspartic proteinases. The putatively active cathepsin D1 has a molecular mass of 36.4 kDa and a calculated pI of 4.14 and possesses three potential glycosylation sites. The sequences showed highest similarities with cathepsin D from insects but also with another crustacean cathepsin D. Cathepsin D1 transcripts were quantified during a starvation period using real-time qPCR. In H. americanus, 15 days of starvation did not cause significant changes, but subsequent feeding caused a 2.5-fold increase. In H. gammarus, starvation caused a 40% reduction in cathepsin D1 mRNA, and no effect was observed with subsequent feeding.

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“…Mites use both extracellular and intracellular digestión, with the latter occurring in free-floating gut wallderived epithelial cells that ingest and digest food particles. The midgut is the site for synthesis and secretion of digestive enzymes and absorption of nutrients, Processed food and cells pass into the posterior midgut, subsequently compacted in the hindgut and excreted as faecal pellets (Hamilton et al 2003). Mite species that feed on plants rely mostly on cysteine peptidase activities for the digestión of dietary proteins (Nisbet and Billingsley 2000).…”

Section: Introductionmentioning

confidence: 99%

Expression of a barley cystatin gene in maize enhances resistance against phytophagous mites by altering their cysteine-proteases

et al. 2010

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Phytocystatins are inhibitors of cysteine-proteases from plants putatively involved in plant defence based on their capability of inhibit heterologous enzymes. We have previously characterised the whole cystatin gene family members from barley (HvCPI-1 to HvCPI-13). The aim of this study was to assess the effects of barley cystatins on two phytophagous spider mites, Tetranychus urticae and Brevipalpus chilensis. The determination of proteolytic activity profile in both mite species showed the presence of the cysteine-proteases, putative targets of cystatins, among other enzymatic activities. All barley cystatins, except HvCPI-1 and HvCPI-7, inhibited in vitro mite cathepsin L-and/or cathepsin B-like activities, HvCPI-6 being the strongest inhibitor for both mite species. Transgenic maize plants expressing HvCPI-6 protein were generated and the functional integrity of the cystatin transgene was confirmed by in vitro inhibitory effect observed against T urticae and B. chilensis protein extracts. Feeding experiments impaired on transgenic lines performed with T urticae impaired mite development and reproductive performance. Besides, a significant reduction of cathepsin L-like and/or cathepsin B-like activities was observed when the spider mite fed on maize plants expressing HvCPI-6 cystatin. These findings reveal the potential of barley cystatins as acaricide proteins to protect plants against two important mite pests.

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A physiological and biochemical model for digestion in the ectoparasitic mite, Psoroptes ovis (Acari: Psoroptidae)

Cited by 46 publications

References 108 publications

Os parasitas de ovinos

Os parasitas de ovinos

Aspartic Cathepsin D Endopeptidase Contributes to Extracellular Digestion in Clawed Lobsters Homarus americanus and Homarus gammarus

Expression of a barley cystatin gene in maize enhances resistance against phytophagous mites by altering their cysteine-proteases

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