A research group has discovered a new North American trematode, Ochetosoma elongatum, for the first time in Japan in the oral cavities of three native snake species in the Kanto region.

In addition to investigating its life cycle in the wild, the authors conducted a comprehensive literature review to explore the route of invasion of this parasite. The findings of this study were published in Parasitology International.

Ochetosoma elongatum is a snake trematode which is distributed in North America. However, the adult was discovered for the first time in Japan in the mouths of three native snake species in the Kanto region. A previous study reported the presence of a related North American trematode (Ochetosoma kansense) in western Japan, indicating that the two North American trematodes are now infecting native snakes in Japan.

The sporocysts and cercariae were detected in the North American freshwater snail Physella acuta, which has introduced and established its population in Japan. The cercarae is thought to infect frogs and develop into metacercariae. The metacercariae develop into adults after the host frog was fed by the Japanese snakes, the definitive host.

The snail Physella acuta are thought to be introduced to Japan with imported freshwater plants for aquariums. The increased demand for ornamental fish and exotic pets likely led to the introduction of infected Physella acuta snails and/or North American snakes, resulting in the introduction of this parasite to Japan.

The study’s authors included Harushige Seo (an undergraduate student), Eriko Ansai (a graduate student), Tetsuya Sase (an undergraduate student), Associate Professor Tsukasa Waki, and Lecturer Yosuke Kojima from the Faculty of Science, Toho University.

A combined team of bio researchers and roboticists from Brigham and Women’s Hospital, in the U.S., and the iPrint Institute, in Switzerland, has developed a tiny swimming robot using human motor neurons and cardiomyocytes grown to emulate muscle tissue.

Their paper is published in the journal Science Robotics. Nicole Xu, a mechanical engineer at the University of Colorado Boulder, has published a Focus piece in the same journal issue outlining ongoing work to create bioinspired robots using animal tissue.

For many years, science fiction writers and movie makers have used the idea of combining electronics, computers and animal tissue to create robots with unique and sometimes terrifying attributes. In the real world, Xu describes such work as ongoing.

Animals, including humans, have abilities that far surpass anything robots can do. Doing laundry, for example, requires a myriad of skills, including sorting dirty clothes, choosing washer and dryer settings, and folding or hanging clothes.

Such activities require both dexterity and mental processing. Because of that, roboticists are exploring the development of biohybrid robots. The research team created a ray-like swimming robot with a computer brain that controls human muscle cells activated by human motor neurons.

To create the robot, the researchers cultured both motor neurons and cardiomyocytes that were produced using human pluripotent stem cells. The cardiomyocytes were programmed to grow into muscle cell tissue on a scaffolding that resembled ray fins in a way that allowed them to junction with the motor neurons.

This allowed for the creation of electrical synapses. Some of the motor neurons were then connected to an electronic processor that served as the robot’s brain. It housed Wi-Fi circuitry that transferred signals from human controllers to either the left or right fin, or both.

In this way, the researchers were able to control the movement of their robot, eventually giving it the ability to swim.

Over time, the research team found they could maneuver the robot with precision, including making sharp turns. They also found they could make it swim at speeds of up to 0.52 ± 0.22 mm/s.

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The tagging of wildlife provides important insights into their movements, physiology, and behavior amid globally changing ecosystems. However, the stress caused by capture, handling, and tagging can have an effect on the locomotion and activity of the animals and thus also affect the validity of the collected data. Therefore, Potsdam researchers led by Jonas Stiegler and Niels Blaum, in collaboration with over 100 other scientists worldwide, analyzed the data of 1,585 individuals from 42 species that had been fitted with GPS collars.

The research is published in the journal Nature Communications.

“Over a period of 20 days after release, we analyzed how active the animals were and what distances they covered in order to see how much the animals deviated from their normal behavior and how long it took them to recover from the disturbance,” explains Stiegler, the lead author of the study.

30 of the 42 species studied changed their behavior significantly in the first few days after release, although there were noticeable differences between the species. For example, predators covered shorter distances on average after release, while most herbivores covered longer distances than normal. Moose (63% further than the long-term average) and eland (+52%) had the largest increase in displacement distance, while leopards (-65%) and wolves (-44%) exhibited the largest decrease.

In general, omnivores and carnivores were less active in the first few days, while herbivores showed both increased and decreased activity rates. However, the data also revealed that the animals “recovered” at different rates: All species basically returned to their normal behavior within four to seven days.

Omnivores and carnivores went back to a normal degree of activity and movement within five to six days. Herbivores exhibited a normal range of movement more quickly (four to five days), but only returned to their usual degree of activity at a later stage (six to eight days). In addition, larger animals recovered more quickly than smaller ones.

“However, it was particularly noteworthy that animals whose habitat is more strongly influenced by humans were the first to return to normal behavior,” Stiegler said. “Our evaluation clearly shows that the periods over which wild animals are tracked should be longer than one week in order to obtain meaningful results and to actually be able to study their natural behavior.”