Category Archives: Pollution

Friday Fellow: Beggar’s tick

ResearchBlogging.orgby Piter Kehoma Boll

What if the cure for cancer has been living in your garden all this time and you have been trying to get rid of it because it is an annoying weed?

I cannot assure you that the answer lies in today’s Friday Fellow, but it certainly has a good potential. Its name is Bidens pilosa, commonly known as beggar’s tick, beggar ticks, black jack, cobbler’s pegs or Spanish needle.

Not extravagant, but discrete. This is Bidens pilosa. Photo by Wibowo Djatmiko.*

Not extravagant, but discrete. This is Bidens pilosa. Photo by Wibowo Djatmiko.*

Native from the Americas, where it grows in open fields and forest glades, the beggar’s tick is now found worldwide, from Eurasia and Africa to Australia and the Pacific Islands. At first it does not call much attention while growing among other weeds. It grows up to 1.8 m tall and has small discrete flowers in a daisy-like head, with a handful of white ray florets and a small disc of yellow florets.

The problem with this fellow happens when you have to pass among them after the flowers have turned into fruits.

The terrible evil infructescence of the beggar's tick. Photo by

The terrible evil infructescence of the beggar’s tick. Photo by Wibowo Djatmiko.*

The fruits of the beggar’s tick are small, stiff, dry rods with about 2–4 small heavily barbed awns at the end. They are arranged in spherical infructescences are are eager to stick on any passing animal. The small barbed awns catch onto fur and clothes and the fruits are easily dispersed to other areas. It is a classical example of zoochory, i.e., seed dispersal by animals. If you live in an area where this plant is common, you most likely have had the experience of finding your clothes full of those prickling seeds, especially after playing, working or simply walking through a field.

But the beggar’s tick is much more than a dull and annoying weed. In Subsaharan Africa, it is one of the most widely eaten plants. Its leaves are edible when cooked, but have a strong and unpleasant taste.

Furthermore, the beggar’s tick is used in traditional medicine in South America and several studies have found out that it is indeed a powerful medicine. Extracts from the plant have shown several medicinal properties, including:

  • Antibacterial and antifungal activity
  • Antimalarial activity
  • Anti-herpes simplex activity
  • Ability to reduce tumoral and leukemic cells
  • Immunosuppressive and anti-inflammatory effects

If this were not enough, the beggar’s tick has the ability to bioacumulate cadmium in its tissues, so that it can be used to depollute cadmium-contaminated soils.

The next time you find your clothes full of beggar’s ticks, remember that it is more, much more, than simply an annoying weed.

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Brandão, M., Krettli, A., Soares, L., Nery, C., & Marinuzzi, H. (1997). Antimalarial activity of extracts and fractions from Bidens pilosa and other Bidens species (Asteraceae) correlated with the presence of acetylene and flavonoid compounds Journal of Ethnopharmacology, 57 (2), 131-138 DOI: 10.1016/S0378-8741(97)00060-3

Chang, J., Chiang, L., Chen, C., Liu, L., Wang, K., & Lin, C. (2001). Antileukemic Activity of Bidens pilosa L. var. minor (Blume) Sherff and Houttuynia cordata Thunb. The American Journal of Chinese Medicine, 29 (02), 303-312 DOI: 10.1142/S0192415X01000320

Chiang, L., Chang, J., Chen, C., Ng, L., & Lin, C. (2003). Anti-Herpes Simplex Virus Activity of Bidens pilosa and Houttuynia cordata The American Journal of Chinese Medicine, 31 (03), 355-362 DOI: 10.1142/S0192415X03001090

Deba, F., Xuan, T., Yasuda, M., & Tawata, S. (2008). Chemical composition and antioxidant, antibacterial and antifungal activities of the essential oils from Bidens pilosa Linn. var. Radiata Food Control, 19 (4), 346-352 DOI: 10.1016/j.foodcont.2007.04.011

Kviecinski, M., Felipe, K., Schoenfelder, T., de Lemos Wiese, L., Rossi, M., Gonçalez, E., Felicio, J., Filho, D., & Pedrosa, R. (2008). Study of the antitumor potential of Bidens pilosa (Asteraceae) used in Brazilian folk medicine Journal of Ethnopharmacology, 117 (1), 69-75 DOI: 10.1016/j.jep.2008.01.017

Oliveira, F., Andrade-Neto, V., Krettli, A., & Brandão, M. (2004). New evidences of antimalarial activity of Bidens pilosa roots extract correlated with polyacetylene and flavonoids Journal of Ethnopharmacology, 93 (1), 39-42 DOI: 10.1016/j.jep.2004.03.026

Pereira, R., Ibrahim, T., Lucchetti, L., da Silva, A., & de Moraes, V. (1999). Immunosuppressive and anti-inflammatory effects of methanolic extract and the polyacetylene isolated from Bidens pilosa L. Immunopharmacology, 43 (1), 31-37 DOI: 10.1016/S0162-3109(99)00039-9

Sun, Y., Zhou, Q., Wang, L., & Liu, W. (2009). Cadmium tolerance and accumulation characteristics of Bidens pilosa L. as a potential Cd-hyperaccumulator Journal of Hazardous Materials, 161 (2-3), 808-814 DOI: 10.1016/j.jhazmat.2008.04.030

Wikipedia. Bidens pilosa. Available at < >. Access on July 31, 2016.

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Filed under Botany, Disease, Friday Fellow, Pollution

Friday Fellow: Red Euglene

by Piter Kehoma Boll

Don’t be as fool as the Egyptian Pharaoh in the myth of the Plagues of Egypt. If you happen to find a lake with red water, as in the picture below, it is certainly not blood. It’s simply… a toxic alga!

Sometimes one may find the waters of a like turned red. Photo extracted from, posted by user Carlmor.

Sometimes one may find the waters of a lake turned red. Photo extracted from, posted by user Carlmor.

The creature responsible for this coloration is today’s Friday Fellow: Euglena sanguinea, or the red euglene, a microscopic freshwater protist with a worldwide distribution. This unicellular organisms has a red color due to the presence of astaxanthin, a pigment also found in some fish, like salmon, and in crustaceans, like shrimp and crayfish. Some birds may also have this pigment in their feathers. In red euglenes, astaxanthin acts as a protection against ultraviolet radiation, so that the higher the amount of UV radiation, the redder the algae become.

A fraction of a population of red euglenes under the microscope. Photo extracted from, posted by user Carlmor.

A fraction of a population of red euglenes under the microscope. Photo extracted from, posted by user Carlmor.

When the conditions are adequate, usually due to high temperatures and high amounts of nutrients, the red euglene may overpopulate and cover the entire surface of water bodies, making it appear red. Water pollution, especially from domestic wastewater, is one of the main causes of nutrient increase in water bodies and thus a direct cause of many algal blooms.

The red euglene is known to produce euglenophycin, a very potent ichthyotoxin, i.e., a compound that is toxic to fish. As a result, red euglene blooms can lead to high fish mortality, making it an organism of major concern to fish breeders.

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Gerber, S.; Häder, D-P. 2006. Effects of enhanced UV-B radiation on the red coloured freshwater flagellate Euglena sanguineaFEMS Microbiology Ecology, 13(3): 177-184. DOI: 10.1111/j.1574-6941.1994.tb00064.x

Wikipedia. Euglena sanguinea. Available at <;. Access on  January 07, 2016.

Zimba, P. V.; Rowan, M.; Triemer, R. 2004. Identification of euglenoid algae that produce ichthyotoxin(s). Journal of Fish Diseases, 27: 115-117.

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Filed under Algae, Conservation, Ecology, Friday Fellow, Pollution

The World Beyond Your Trash Bag

by Piter Kehoma Boll

It’s been a while since I had the idea of writing a post about the garbage problem, but it’s difficult to find the best way to start it, so let’s try to simply talk and see how it flows.

Some months ago, as part of a field activity, I visited with some colleagues and a professor some places intended to manage waste. At first we thought it would be a boring day seeing garbage everywhere, but it wasn’t boring at all. In fact it was very enlightening.

After that day, I can say for sure that we have no idea about the horror caused by our garbage. We are used to simply throw our waste in the trash bag and let the truck take it away, just as it would miraculously disappear and everything would be fine. Well… that’s not what happens.

We visited a landfill in the city of Campo Bom, which has a population of only 64 thousand people and receives about 50 tons of waste every day.

Garbage accumulated in the last hours. Beautiful, huh? Photo by Piter Kehoma Boll.

The place was full of vultures and herons scavenging the waste. Photo by Tiago Finger Andreis.

A recycling plant operates with the landfill where about 40 workers sort the garbage on a conveyor belt, but only about 4 to 6 % is recycled.

Conveyor belt where the garbage is sorted. Photo by Tiago Finger Andreis.

The rest is sent to the landfill where it will be buried, leading to many potential impacts to the environment, including soil and water pollution due to the leakage of contaminants, as well as by the solid residues themselves. It can also pollute the air by releasing methane from the decay of organic material and cause injuries to wildlife.

The landfill already full. This waste will never be recycled. Photo by Piter Kehoma Boll.

All those impacts could be greatly reduced if most of the waste material could be reused. So we may ask why so little of it is recycled. Well, in part it is our own fault because we don’t care so much about the way we discard our waste.

Most people simply throw everything together. Organic and inorganic waste are not set apart and, even when people separate fruit peels from plastic, they still mix a dirty plastic container with remains of yogurt with paper and other stuff, causing the organic remains to flow over other clean materials and many times causing them to become unfeasible to recycle.

Recycling, however, faces many other challenges. Many materials are not designed to be recycled, so the most common forms of “recycling” don’t include the reuse of the material for the same purpose, but rather to another. For example, most white paper is recycled to become paperboard and not new white paper. It does, of course, reduce the amount of raw material necessary, but not always targeting the most critical points.

That’s why recycling is connected to the other 2 Rs in the 3R concept: reduce, reuse, recycle. We should try to use less resources and buy less things (reduce), but once we acquired something, we must try to use it as many times as possible (reuse) and, after not being able to go on using it, we got to find a purpose other than throwing it away (recycling).

I’m telling all this stuff and you are probably thinking that you hear that all the time. Yeah, maybe, but I wish everybody visited a landfill someday to see with their own eyes the tragedy that we are causing to our planet due to our unbridled consumption of resources.

To finish, I would like to share an interesting graph that was presented to me by Meika Jensen from It deals with the problem of ocean pollution, something directly related to waste management. Take a look:
Ocean of Garbage


Filed under Conservation, Ecology, Pollution