Lactating tsetse flies models for lactating mammals?

Apr 18, 2012
There have been a large number of studies about SMase and associated enzymes in mammals, but almost none in insects. This image shows immunolocalization of SMase in the tsetse fly reproductive tract during pregnancy. Credit: Image modified from Benoit et al., Biol Reprod 2012.

An unprecedented study of intra-uterine lactation in the tsetse fly, published 18 April 2012 in Biology of Reproduction's Papers-in-Press, reveals that an enzyme found in the fly's milk functions similarly in mammals, making the tsetse a potential model for lipid metabolism during mammalian lactation.

Better yet, reduced levels of this enzyme led to poor health in offspring, leading the authors to suggest that targeting it could help decrease the tsetse population in Africa and so reduce the incidence of sleeping sickness.

Tsetse flies are bloodsucking flies that inhabit much of subsaharan Africa. They are similar in size to a horsefly and breed along rivers and streams. A pathogenic species of parasite in the genus Trypanosoma can be taken in by the fly while taking a blood meal from an infected human or animal. Flies carrying the parasite can then transmit it to other humans or animals. The disease caused by the is known as sleeping sickness in humans and nagana in wild and , including pigs, cattle, and horses.

affects about 37 countries and 60 million people, and an estimated 50,000 to 70,000 individuals are infected. Efforts to combat the disease are varied. One effective technique involves sterilizing male tsetse flies and then releasing them to compete with the wild males for breeding rights. The authors of this study suggest that manipulating production of the SMase enzyme and other essential in female flies could also aid population reduction efforts.

This is the first study to uncover the of lactation in tsetse flies. Yale University's Joshua B. Benoit and colleagues, with the help of researchers from the Slovak Academy of Sciences, documented that a sphingomyelinase (SMase) enzyme is present in tsetse milk during lactation. This enzyme is essential for the production of a key component of cell membranes and it functions similarly during mammalian lactation.

Unlike most flies, the female tsetse produces a single egg and ovulates the egg into a uterus. When the larva hatches, it remains in the uterus until it has completed larval development. While the larva is in the uterus, the female fly expresses SMase as a component of the milk secretion of the fly's milk glands. The larva feeds on the milk, and acidic conditions in the larval gut activate the enzyme. When the researchers reduced SMase levels in the lactating mother, the offspring's development and health were impaired.

In humans, defects in SMase-encoding genes causes Niemann-Pick Disease, a neurodegenerative disorder that, in severe cases, causes death before three years of age. Although the mammalian and insect SMases differ, the basic structure and function of the enzymes and their products are similar. Thus, insects could serve as model systems for studying metabolic diseases related to SMase deficiency.

Explore further: Danish museum discovers unique gift from Charles Darwin

More information: Benoit JB, Attardo GM, Michalkova V, Takac P, Bohova J, Aksoy S. Sphingomyelinase activity in mother's milk is essential for juvenile development: a case from lactating tsetse flies. Biol Reprod 2012; (in press). Published online ahead of print 18 April 2012; DOI 10.1095/biolreprod.112.100008

Provided by Society for the Study of Reproduction

5 /5 (3 votes)

Related Stories

Fly gut bacteria could control sleeping sickness

May 11, 2010

A new bacterial species, found in the gut of the fly that transmits African sleeping sickness, could be engineered to kill the parasite that causes the disease. The study, published in the International Journal of Systematic an ...

Revealing secrets of 'African sleeping sickness'

Oct 27, 2008

Scientists in the United Kingdom and Russia are reporting identification of a long-sought chink in the armor of the parasite that causes African sleeping sickness, a parasitic disease that kills at least 50,000 people each ...

Recommended for you

Danish museum discovers unique gift from Charles Darwin

Aug 29, 2014

The Natural History Museum of Denmark recently discovered a unique gift from one of the greatest-ever scientists. In 1854, Charles Darwin – father of the theory of evolution – sent a gift to his Danish ...

Top ten reptiles and amphibians benefitting from zoos

Aug 29, 2014

A frog that does not croak, the largest living lizard, and a tortoise that can live up to 100 years are just some of the species staving off extinction thanks to the help of zoos, according to a new report.

User comments : 0