User talk:PencilNick

Feeding and Nutrition

Developing Schistosoma mansoni worms that have infected their definitive hosts, prior to the sexual pairing of males and females, require a nutrient source in order to properly develop from cercariae to adults. The developing parasites lyse host red blood cells to gain access to nutrients vital to their survival in the host environment; the hemoglobin and amino acids they contain can be used by the worm to form proteins.^[1] While hemoglobin is digested intracellularly, initiated by salivary gland enzymes, iron waste products cannot be used by the worms, and are typically discarded via regurgitation.^[2]

A study by Kasschau et al. tested the effect of temperature and pH on the ability of developing S. mansoni to lyse red blood cells.^[1]  The researchers found that the parasites were best able to destroy red blood cells for their nutrients at a low pH and a high temperature.^[1]

Locomotion

S. mansoni is actively locomotive in primarily two stages of its life cycle: as cercariae swimming freely through a body of freshwater to locate the epidermis of their human hosts, and as developing and fully-fledged adults, migrating throughout their primary host upon infection.^[2] Free-swimming, the cercarial stage of the parasite is attracted to the presence of fatty acids on the skin of their definitive host which it senses through the freshwater medium surrounding it, in which the parasite responds to changes in light and temperature to navigate.^[3] A study by Ressurreicao et al. tested the roles of various protein kinases in the ability of the parasite to navigate its medium and locate a penetrable host surface.^[3] The researchers found that extracellular signal-regulated kinase and protein kinase C both respond to changes in medium temperature and light levels, and the stimulation of p38 mitogen-activated protein kinase, associated with recognition of parasite host surface, results in a glandular secretion that deteriorates the host epidermis, and allows the parasite to burrow into its host.^[3]

The nervous system of S. mansoni contains bilobed ganglia and several nerve cords which splay out to every surface of the body; serotonin is a transmitter distributed widely throughout the nervous system and plays an important role in nervous reception, and stimulating mobility in the animal.^[4] Because of the importance of locomotion in the parasite’s pathology, worms infecting the host burrowing through blood vessels to develop and find a mate for copulation,^[2] pharmacologists have targeted parasite muscles, means through which locomotion can occur, with various drugs to weaken the pathology of the organism on its host. Mendonca-Silva et al. found that in the parasite, voltage-operated calcium ion channels control the contraction of muscle fibers to an extent, and when introduced to dihydropirodine drugs, the activity of these channels is limited and muscle contraction may not occur.^[5]

Hi Nick! Thank you for your notes on my draft for the honey bee article, I will make my edits with your comments in mind. I very much liked your draft for the addition of feeding and locomotion sections on the Schistosoma mansoni page. I'll admit, I was not thrilled to read about blood-thirsty parasites but I was fascinated by the description of the mechanisms by which they seek out their hosts. In general, your draft was very clear and you provided enough detail without overwhelming the reader. My only note is regarding the section about S. mansoni nervous control, I felt as though the second sentance, "(b)ecause of the importance of locomotion... muscle contraction may not occur", could be broken into two or more sentences for the sake of simplicity as I found myself needing to reread this portion a few times before I fully understood the meaning. I would have also liked a little more detail about the actual nutrition requirements for S. mansoni (i.e. how many red blood cells do they typically lyse per feeding or lifecycle) but I liked that you included the information about their preferred pH and temperature. Reading your draft has encouraged me to read further on the S. mansoni wiki page, well done! Abigail.langevin.uconn (talk) 21:20, 28 April 2016 (UTC)

@PencilNick: Nick, thanks for the very personable and helpful and detailed comments on Abby's honey bee contribution!Rico.schultz (talk) 13:25, 29 April 2016 (UTC)

@PencilNick: Nick, I see that you posted to the talk page of Schistosoma mansoni. You got some feedback from an editor and it seems like he did some work on the article, and requested some links. Check it out! Rico.schultz (talk) 17:54, 3 May 2016 (UTC)