BIOL113 M2 L8

• SARS-CoV-2 is a novel coronavirus that was first detected in China in 2019. What evidence has been used to suggest that this virus arose as a spillover event from bats to humans? 

  Genetic sequencing of the viruses and other coronaviruses suggests that the new SARS-CoV-2 virus is most closely related to coronaviruses of bats.  Early access to these genome sequences was key in making the vaccines.
• In the 1860s scientists believed that Lichens were plants. A Swiss botanist overturned this idea in 1868 by proposing that lichens were made up of two organisms in a symbiotic mutualistic relationship. Who was this Swiss botanist? 

  Simon Schwendener 
• In the work of Yu Matsumura, it was reported that in a family of cicadas a Yeast Like Symbiont had replaced a bacterial endosymbiont. What evidence suggested that the parasitic Ophiocordyceps had been coopted into this symbiont role? 

  The phylogenetic tree of YLS and Ophiocordyceps both shared a last common ancestor AND Ophiocodyceps had apparently evolved back to parasitism from YLS. 
• The term Endosymbiont means "living within" and these associations ... (complete the sentence). 

  can be positive or negative for either party. 
• A lichen can be described as a mutualistic symbiosis between an ascomycete fungus, ... and ....

  algal chlorophyll

  A basidiomycetes yeast
• what are the two ways in which fungi, like Cordyceps, is hypothesised to control the behaviour of an animal

  effector secretion and through growing around key muscle groups
• how do fungi chemically control insects?

  By excreting effector molecules which directly influence the neural and hormonal systems of their host insects. These effector molecules may mimic or interfere with the host's neurotransmitters or hormones, disrupting normal physiological processes and inducing aberrant behaviors. By manipulating the host's behavior in this way, the fungus can orchestrate the host's movements to its advantage, ultimately facilitating the dispersal of its spores.
• how do fungi mechanically control insects?

  By growing in and around the muscles of their host insects. This growth pattern is thought to be strategic, as it allows the fungus to anchor itself firmly within the host's body and exert greater control over its movements. By growing around key muscle groups, such as the mandibular and thoracic muscles, the fungus may interfere with the insect's ability to move normally, leading to behaviors that are conducive to the fungus's reproductive needs, such as climbing to an elevated location for spore dispersal.
• Fungi

  Can form intimate relationships with other organisms
• Dr. Toby Spribille's study on lichen led to the discovery of a yeast-like fungus involved in lichen symbiosis
• Describe the study which showed that a yeast like fungus was involved in lichen symbiosis.

  Dr. Toby Spribille sequenced samples of lichen and examined the ascomycota genes, searching for evidence of vulpinic acid production. After failing to find any evidence of vulpinic acid production in the ascomyctes genes, he expanded his search and discovered that the genes related to this compound came from a different fungal group, basidiomycetes. By probing basidiomycete DNA, he identified single-celled yeast-like fungi within the lichen, challenging previous assumptions about lichen symbiosis.