Interestingly, transcriptome analysis has shown that the gut microbe Lactobacillus apis triggers the expression of PGRP-S3, Spätzle, and antibacterial proteins, which can inhibit infection by Hafnia alvei; further genomic analysis suggested that the S-layer proteins of L. apis are potentially involved in honeybee Toll signaling and in the activation of antibacterial protein production in honeybees [81]. The gene discussed is TLR4; the disease is infection.