Friday Fellow: Common Stinkhorn

by Piter Kehoma Boll

Today things are getting sort of pornographic again. Some time ago I introduced a plant whose flowers resemble a woman’s vulva, the asian pigeonwing, and now is time to look at something of the other sex. And what could be better than the shameless penis? That’s the translation of the scientific name of this mushroom, Phallus impudicus, whose common name in English is much more discrete: common stinkhorn.

Phallus_impudicus2

Standing proud and shameless. Photo by flickr user Björn S…*

Found throughout Europe and parts of North America in deciduous woods, the common stinkhorn is easily recognizable for its phallic shape and even more for its foul smell that resembles carrion. This odor attracts insects, especially flies, that carry the spores away. This is a different method from the one used by most fungi, which simply release the spores in the air. Some people may mistake the common stinkhorn for morels (genus Morchella) but the two are completely unrelated, being from different phyla.

Despite the foul smell, the common stinkhorn is edible, especially in its first stages of development, when it resembles an egg. Due to its phallic shape, it is also seen as an aphrodisiac in some culture, as it is common with genitalia-shaped lifeforms.

Phallus_impudicus3

The immature fruiting body of Phallus impudicus is the most commonly eaten form. Photo by Danny Steven S.*

The common stinkhorn seems to have some anticoagulant properties and can be used for patients susceptible to thrombosis in the veins, such as patients treating breast cancer.

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ResearchBlogging.orgReferences:

Kuznecov, G., Jegina, K., Kuznecovs, S., & Kuznecovs, I. (2007). P151 Phallus impudicus in thromboprophylaxis in breast cancer patients undergoing chemotherapy and hormonal treatment The Breast, 16 DOI: 10.1016/s0960-9776(07)70211-4

SMITH, K. (2009). On the Diptera associated with the Stinkhorn (Phallus impudicus Pers.) with notes on other insects and invertebrates found on this fungus. Proceedings of the Royal Entomological Society of London. Series A, General Entomology, 31 (4-6), 49-55 DOI: 10.1111/j.1365-3032.1956.tb00206.x

Wikipedia. Phallus impudicus. Available at <https://en.wikipedia.org/wiki/Phallus_impudicus&gt;. Access on March 7, 2017.

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Friday Fellow: Spreading Earthmoss

by Piter Kehoma Boll

If you still think mosses are uninteresting lifeforms, perhaps you will change your mind after knowing the spreading earthmoss, Physcomitrella patens.

Found in temperate regions of the world, except for South America, but more commonly recorded in North America and Eurasia, the spreading earthmoss grows near water bodies, being one of the first species to colonize the exposed soil around pools of water. Although widely distributed, it is not a common species.

Physcomitrella_patens

The spreading earthmoss growing on mud. Photo by Hermann Schachner.

Since the beginning of the 1970s, the spreading earthmoss has been used as a model organism, especially regarding gene manipulation. Differently from what occurs in vascular plants, the dominant life phase in mosses is the gametophyte, an haploid organism, meaning it has only one copy of each chromosome in its cells. This is an ideal condition for the study of gene expression, as the activation or inactivation of a gene is not hindered by a second one in another copy of the chromosome in the same cell.

Physcomitrella_patens_ecotypes

Physcomitrella patens growing in the lab. Credits to the Lab of Ralf Reski.*

By controlling gene expression in the spreading earthmoss, researches can track the role of each one of them in the plant’s development. Comparing these data with that known from flowering plants, we can have a better understanding of how the plant kingdom evolved.

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ResearchBlogging.orgReferences:

Cove, D. (2005). The Moss Physcomitrella patens Annual Review of Genetics, 39 (1), 339-358 DOI: 10.1146/annurev.genet.39.073003.110214

Schaefer, D. (2001). The Moss Physcomitrella patens, Now and Then PLANT PHYSIOLOGY, 127 (4), 1430-1438 DOI: 10.1104/pp.127.4.1430

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Land snails on islands: fascinating diversity, worrying vulnerability

by Piter Kehoma Boll

The class Gastropoda, which includes snails and slugs, is only beaten by the insects in number of species worldwide, having currently about 80 thousand described species. Among those, about 24 thousand live on land, where they are a very successful group, especially on oceanic islands.

The Hawaiian Islands alone, for example, have more than 750 snail species and there are more than 100 endemic species in the small island of Rapa in the South Pacific. This diversity is much higher than that in any continental place, but the reason for that is not completely understood.

Mandarina

A land snail of the genus Mandarina, endemic to the Ogasawara Islands, Japan. Photo by flickr user kmkmks (Kumiko).*

One of the most likely explanations for this huge diversity on islands is related to the lack of predators. The most common predators of snails include birds, mammals, snakes, beetles, flatworms and other snails. Most of those are not present in small and isolated islands, which allows an increase in land snail populations in such places. Without too much dangers to worry about, the community of land snails n islands can explore a greater range of niches, eventually leading to speciation.

Unfortunately, as always, the lack of danger leads to recklessness. Without predators to worry about, insular land snails tend to lay fewer eggs than their mainland relatives. If there is no danger of having most of your children eaten, why would you have that many? It is better to lay larger eggs, putting more resources on fewer babies, and so assure that they will be strong enough to fight against other snail species. Afterall, the large number of species in such a small place as an island likely leads to an increased amount of competition between species.

But why is this recklessness? Well, because you never known when a predator will arrive. And they already arrived… due to our fault.

The diversity of insular land nails was certainly affected by habitat loss promoted by humans, but also by predators that we carried with us to the islands, whether intentionally or not. These predators include rats, the predatory snail Euglandina rosea and the land flatworm Platydemus manokwari, the latter being most likely the worst of all.

800px-platydemus_manokwari

The flatworm Platydemus manokwari in the Ogasawara Islands. Photo by Shinji Sugiura.

This flatworm arrived at the Chichijima Island, part of the Ogasawara Islands in the Pacific Ocean, in the early 1990s and in about two decades it led most land snail species on the island to extinction and many more are about to face the same fate on this island and on others. Not being prepared for predators, these poor snails cannot reproduce fast enough to replace all individuals eaten by the flatworm.

We have to act quickly if we want to save those that are still left.

See also: The New Guinea flatworm visits France – a menace.

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ResearchBlogging.orgReferences and further reading:

Chiba, S., & Cowie, R. (2016). Evolution and Extinction of Land Snails on Oceanic Islands. Annual Review of Ecology, Evolution, and Systematics, 47 (1), 123-141 DOI: 10.1146/annurev-ecolsys-112414-054331

Sugiura, S., Okochi, I., & Tamada, H. (2006). High Predation Pressure by an Introduced Flatworm on Land Snails on the Oceanic Ogasawara Islands. Biotropica, 38 (5), 700-703 DOI: 10.1111/j.1744-7429.2006.00196.x

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Friday Fellow: Toxo

by Piter Kehoma Boll

If I had to bet on a parasite that you who are reading this probably have in your body, I’d go for today’s fellow, the protist Toxoplasma gondii, sometimes simply called toxo.

Found worldwide, the toxo is one of the most common parasites in humans, with estimations that about half of the world’s population is infected. Fortunately, this creature usually occurs in a latent form and does not offer great risks, but eventually it may develop into a more serious condition called toxoplasmosis, especially in people with weakened immunity.

But let’s take a closer look at this tiny fellow.

Toxoplasma_gondii_oocyst

Oocysts of Toxoplasma gondii. This is the form found in the environment and that can start an infection in your body.

The toxo is a protist belonging to the phylum Apicomplexa, a group of parasitic alveolates that also includes the agent that causes malaria. Although traditionally considered a protozoan, the apicomplexans are closely related to dinoflagellates (which are generally considered as a group of algae). They have a unique organelle called apicoplast, which they use to penetrate a host cell. The apicoplast is derived from a plastid (such as the chloropast), so in a certain way we can say that the apicomplexans are algae that evolved into intracellular parasites!

Toxoplasma_gondii_tachy

Tachyzoites of Toxoplasma gondii stained with Giesma from the peritoneal fluid of a mouse.

The life cycle of the toxo is kind of complex. Let’s start with the inactive form called oocyst, which may be found in the environment. If a warm-blooded animal ingests an oocyst, it will “burst” inside the gut of the animal and release several “quick-moving” forms called tachyzoites. The tachyzoites invade almost any cell of the body and multiply asexually inside it until the cell dies and release them, allowing them to infect more and more cells. When invading the brain, liver and muscles, the tachyzoites usually differentiate into cysts that become inactive. In this stage, the only thing that the toxo wants is that a cat (any species of the family Felidae) eats the host. It may even change the host’s behavior in order to make it bolder and more easily accessible to predators.

Toxoplasma_gondii_cyst

A cyst of Toxoplasma gondii that forms in the muscles, brain and liver of any warm-blooded anymal. All the cyst wants is to be eaten by a cat!

Now let’s assume that a cat ate the host (that was likely a bird or mouse). Inside the cat’s gut, the cyst burst and releases several “slow-moving” forms called bradyzoites. This form invades the epithelial cells of the cat’s intestine and multiply asexually inside them. Eventually, the bradyzoites differentiate into either tachyzoites or gametocytes (sperm- and egg-like cells). When two gametocytes fuse, they form a zygote that matures into an oocyst and is released into the environment, restarting the cycle.

Toxoplasma_life_cycle

The complex life cycle of Toxoplasma gondii. Credits to Mariana Ruiz Villarreal.

As always, the lifecycle of parasites is a wonderful adventure!

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ResearchBlogging.orgReferences:

Tenter, A., Heckeroth, A., & Weiss, L. (2000). Toxoplasma gondii: from animals to humans International Journal for Parasitology, 30 (12-13), 1217-1258 DOI: 10.1016/S0020-7519(00)00124-7

Wikipedia. Toxoplasma gondii. Available at <https://en.wikipedia.org/wiki/Toxoplasma_gondii&gt;. Access on March 6, 2017.

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Friday Fellow: Hooker’s Lips

by Piter Kehoma Boll

We are always fascinated by plants that have some peculiar shape that resemble something else. And certainly one of them is the species I’m introducing today, Psychotria elata, also known as hooker’s lips or hot lips.

Found in the rainforests of Central America, in areas of middle to high elevation, the hooker’s lips is an understory shrub and produces an inflorescence that is surrounded by a pair of bracts that resemble bright red lips. Don’t look too much or you may be tempted to kiss them.

psychotria_elata

“Kiss me”, beg the hooker’s lips. Photo by Wikimedia user IROZ.*

Certainly some creatures do kiss it, especially hummingbirds, which are its pollinators, but also many species of butterflies and bees. However, when they come to kiss the red lips, they have already spread to much, in order to allow the flowers to be exposed, and do not resemble a mouth anymore.

psychotria_elata2

Once the mouth is open, the magic of the kiss is gone. Photo by Dick Culbert.**

After pollination, the flowers develop into blue berries that are easily spotted by birds, which disperse the seeds. As the hooker’s lips produces fruits through the whole year, it is an important food source for fruit-eating birds.

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ResearchBlogging.orgReferences:

EOL –  Encyclopedia of Life. Psychotria elata. Available at <http://eol.org/pages/1106123/overview&gt;. Access on March 5, 2017.

Silva, C., & Segura, J. (2015). Reproductive Biology and Herkogamy of Psychotria elata (Rubiaceae), a Distylous Species of the Tropical Rain Forests of Costa Rica American Journal of Plant Sciences, 06 (03), 433-444 DOI: 10.4236/ajps.2015.63049

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Friday Fellow: Crystalline crestfoot

by Piter Kehoma Boll

Even in the smallest pools or ponds of freshwater lost in a field, the diversity of lifeforms is amazing. Sadly, these environments are one of the most damaged of all ecosystems on earth and we probably have led many tiny species to extinction. Today’s fellow, however, is still alive, and its name is Lophopus crystallinus, or as I decided to call it, the crystalline crestfoot.

lophopus_crystallinus

A colony of Lophopus crystallinus. Photo by Natural History Museum, London.*

The crystalline crestfoot is member of the phylum Bryozoa, sometimes called moss animals. In fact, it was the first bryozoan to be described. As other bryozoans, the crystalline crestfoot lives as a colony of individuals attached to substracts in the lakes and ponds where they exist, which includes Europe and North America. The individuals are not fully independent and have specialized functions within the colony, thus acting as a single superorganism. As a general rule, bryozoans, including the crystalline crestfoot, are filter feeders, extracting particles and microalgae from water.

Despite being considerable tolerant to eutrophication (increase of  organic matter in water) and heavy metal pollution, the crystalline crestfoot is yet threatened by other forms of human impact, such as climate change and certainly by the destruction of its habitat. Once an abundant species, the crystalline crestfoot is now rare and declining. It is currently regarded as a threatened species in the United Kingdom and is the only bryozoan to have a Species Action Plan. Let’s hope we can find a way to avoid it to be wiped out from this world.

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ResearchBlogging.orgReferences:

Elia, A., Galarini, R., Martin Dörr, A., & Taticchi, M. (2007). Heavy metal contamination and antioxidant response of a freshwater bryozoan (Lophopus crystallinus Pall., Phylactolaemata). Ecotoxicology and Environmental Safety, 66 (2), 188-194 DOI: 10.1016/j.ecoenv.2005.12.004

Hill, S., Sayer, C., Hammond, P., Rimmer, V., Davidson, T., Hoare, D., Burgess, A., & Okamura, B. (2007). Are rare species rare or just overlooked? Assessing the distribution of the freshwater bryozoan, Lophopus crystallinusBiological Conservation, 135 (2), 223-234 DOI: 10.1016/j.biocon.2006.10.023

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Friday Fellow: Crawling Spider Alga

by Piter Kehoma Boll

The world of unicelular creatures includes fascinating species, some of which were already presented here. And today one more is coming, the marine phytoplanctonic amoeboid protist Chlorarachnion reptans, which again is a species without a common name, so I created one: crawling spider alga.

chlorarachnion_reptans

A plasmodium of the crawling spider alga Chlorarachnion reptans. Photo by Wikimedia user NEON.*

The crawling spider alga was dicovered in the Canary Islands in 1930. It is an amoeboid alga that forms plasmodia (multinucleated networks) of cells connected by thin strips of cytoplasm (reticulopodia). The reticulopodia are also used to capture prey (bacteria and smaller protists, especially algae) working kind of like a spider web. Additionally, the crawling spider alga has chloroplasts, so being able to conduct photosynthesis. It is, therefore, a mixotrophic organism, having more than one way of feeding.

The chloroplasts of the crawling spider alga, as well of other species in its group, called Chlorarachniophyceae, have four membrane layers and appears to have evolved from a green alga that was ingested and became an endosymbiont. As a result, the chloroplast of the crawling spider alga has two sets of DNA, one from the original chloroplast that came from an endosymbiotic cyanobacteria (located inside the inner membrane) and one of the green algae (between the two inner and the two outer membranes).

Although traditionally seen as a group of algae, the chlorarachniophytes are not closely related to the more “typical” algae, such as red, green, brown and golden algae or diatoms. They are actually relatives of other protists with thin net- or thread- like pseudopods, such as radiolarians and foraminifers, forming with them the group Rhizaria.

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ResearchBlogging.orgReferences:

AlgaeBase. Chlorarachnion reptans Geitler. Available at <http://www.algaebase.org/search/species/detail/?species_id=59340&gt;. Access on March 5, 2017.

EOL – Encyclopedia of Life. Chlorarachnion reptans. Available at <http://eol.org/pages/897235/overview&gt;. Access on March 5, 2017.

Hibberd, D., & Norris, R. (1984). Cytology and ultrastructure of Chlorarachnion reptans (Chlorarachniophyta divisio nova, Chlorarachniophyceae classis nova) Journal of Phycology, 20 (2), 310-330 DOI: 10.1111/j.0022-3646.1984.00310.x

Ludwig, M., & Gibbs, S. (1989). Evidence that the nucleomorphs of Chlorarachnion reptans (Chloraracnhiophyceae) are vestigial nuclei: morphology, division and DNA-DAPI fluorescence Journal of Phycology, 25 (2), 385-394 DOI: 10.1111/j.1529-8817.1989.tb00135.x

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