test
node1
BFO:0000003
occurrent
node1->node1
node2
BFO:0000015
process
node1->node2
node3
GO:0003674
molecular_function
node2->node3
node5
GO:0005488
binding
node3->node5
node4
BFO:0000001
entity
node4->node1
node6
GO:0005549
odorant binding
node5->node6