Ecotoxicology of human pharmaceuticals.

Insect digestive enzymes: properties, compartmentalization and function

This review addresses the problems insects and ticks face to feed on blood and the solutions these invertebrates engender to overcome these obstacles, including a sophisticated salivary cocktail of potent pharmacologic compounds. Recent advances in transcriptome and proteome research allow an unprecedented insight into the complexity of these compounds, indicating that their molecular diversity as well as the diversity of their targets is still larger than previously thought.

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Role of arthropod saliva in blood feeding: sialome and post-sialome perspectives.

Tick fever or cattle fever (babesiosis) is economically the most important arthropod-borne disease of cattle worldwide with vast areas of Australia, Africa, South and Central America and the United States continuously under threat. Tick fever was the first disease for which transmission by an arthropod to a mammal was implicated at the turn of the twentieth century and is the first disease to be eradicated from a continent (North America). This review describes the biology of Babesia spp. in the host and the tick, the scale of the problem to the cattle industry, the various components of control programmes, epidemiology, pathogenesis, immunity, vaccination and future research. The emphasis is on Babesia bovis and Babesia bigemina.

https://www.cambridge.org/core/services/aop-cambridge-core/content/view/S0031182004005190

Babesiosis of cattle.

Water balance in land arthropods

The multifunctional, morphologically complex salivary glands are essential to the biological success of ticks and are intricately involved in the transmission of pathogens. They are innervated, and there is convincing evidence that dopamine is a neurotransmitter at the neuroeffector junction controlling fluid secretion. As feeding progresses, the rate of salivary fluid secretion increases greatly, enabling the ixodid tick to concentrate the bloodmeal by returning excess water and ions to the host. Saliva in feeding ticks is rich in bioactive components and exhibits a range of pharmacological properties. Factors identified in saliva or salivary glands include cement to help anchor the mouthparts to the host, various enzymes and inhibitors, histamine agonists and antagonists, prostaglandins, antihemostatic factors, and immuno-modulating factors. A secretion from the salivary glands allows ticks to absorb water from the air during the lengthy periods off their hosts. The physiology of this remarkable organ provides a striking example of strategies that have evolved to meet the challenge of a unique parasitic life style.

Tick salivary gland physiology

Salivary glands in ixodid ticks: control and mechanism of secretion

The salivary glands are the organs of osmoregulation in ticks and, as such, are critical to the biological success of ticks both during the extended period off the host and also during the feeding period on the host. Absorption of water vapour from unsaturated air into hygroscopic fluid produced by the salivary glands permit the tick to remain hydrated and viable during the many months between blood-meals. When feeding, the tick is able to return about 70% of the fluid and ion content of the blood-meal into the host by salivation into the feeding site. This saliva also contains many bioactive protein and lipid components that aid acquisition of the blood-meal. The salivary glands are the site of pathogen development and the saliva the route of transmission. The importance of the multifunctional salivary glands to tick survival and vector competency makes the glands a potential target for intervention. Here we review the cell biology of tick salivary glands and discuss the application of new approaches such as expressed sequence tag projects and RNA interference to this important area in the field of tick and tick-borne pathogen research.

John R. Sauer

Papers

Tick salivary gland physiology

Salivary glands in ixodid ticks: control and mechanism of secretion

Tick salivary glands: function, physiology and future.

Morphology, physiology, and behavioral biology of ticks

Tick salivary prostaglandins: Presence, origin and significance.