Three Novel Bile Alcohols of Mature Male Sea Lamprey (Petromyzon marinus) Act as Chemical Cues for Conspecifics

Abstract

Sea lamprey, Petromyzon marinus, rely heavily on chemical cues that mediate their life history events, such as migration and reproduction. Here, we describe petromyzone A-C (1-3), three novel bile alcohols that are highly oxidized and sulfated, isolated from water conditioned with spermiated male sea lamprey. Structures of these compounds were unequivocally established by spectroscopic analyses and by comparison with spectra of known compounds. Electro-olfactogram recordings showed that 1 at 10 M was stimulatory to the adult sea lamprey olfactory epithelium, while 2 and 3 were stimulatory at 10 M. Behavioral assays indicated that 1 is attractive, 2 is not attractive or repulsive, and 3 is repulsive to ovulated female sea lamprey. The results suggest that 1 and 2 may be putative pheromones that mediate chemical communication in sea lamprey. The identification of these three components enhances our understanding of the structures and functions of sex pheromone components in this species and may provide useful behavioral manipulation tools for the integrated management of sea lamprey, a destructive invader in the Laurentian Great Lakes.

Petromylidenes A–C: 2-Alkylidene Bile Salt Derivatives Isolated from Sea Lamprey (Petromyzon marinus)

“…), and blank-corrected (0.131 ± 0.005; absolute raw value mean ± S.E.M.) as defined in Equation (1): where Rt is the response magnitude to the test stimulus, Rb is the response magnitude to the blank, and Ra is the response magnitude to L-arginine at 10 −5 M. The L-arginine standard and blank control responses were comparable to previous studies [ 7 , 20 , 23 ]. The detection threshold was defined as the lowest concentration, where the test stimulus elicited a larger response than the blank control (paired t -test, one tailed).…”

“…The threshold of detection—the lowest concentration that elicited an olfactory response greater than the blank water control—for 1 was 10 −9 M (paired t -test, t = −4.94, df = 6, p = 0.001), for 2 was 10 −11 M ( t = −3.53, df = 6, p = 0.006), and for 3 was less than 10 −13 M ( t = −2.52, df = 6, p = 0.023) ( Figure 4 ). The olfactory responses of pheromonal bile acids released by spermiated male sea lamprey, had detection thresholds of 10 −10 M to 10 −13 M [ 7 , 20 ]. The threshold of detection of 3kPZS is 10 −12 M [ 19 ].…”

“…Investigations of pheromone communication in sea lamprey have unveiled that sea lampreys, similar to many other fishes, have an olfactory system which is acutely sensitive to bile salts [ 2 , 3 ]. Furthermore, spermiated male lampreys (sexually mature males with expressible milt) produce unique sulfated bile alcohols with a C24 backbone and 5 α configuration, which aggregate potential mates during spawning [ 4 , 5 , 6 , 7 , 8 ]. In our ongoing investigation for structurally diverse and biologically active compounds released from spawning male sea lampreys, we identified three novel bile salts trivially named petromylidenes A–C ( 1 – 3 , Figure 1 ), and a known compound 3-keto petromyzonol sulfate, 3kPZS ( 4 , Figure 1 ).…”

Discovery and characterization of natural products that act as pheromones in fish

“…. 96 Each has all trans conjugated rings and a 5α-H, except petromyzene A and B, petromyzone C, and DkPES which lack the 5α-H due to a ketene substitution on C-3-C-6. Petromyzene A features a rearranged side chain unique among C-24 bile salts, while petromyzene B possesses a rare cis-11,12-diol on the steroidal C-ring.…”

Spermine in semen of male sea lamprey acts as a sex pheromone

“…EOG setup and recordings were conducted following established procedures by Li and colleagues [54] to determine whether the adult sea lamprey olfactory organ was sensitive to spermine. Sea lampreys were anesthetized with MS222 (100 mg L −1 ), immobilized with an intramuscular injection of gallamine triethiodide (3 mg kg −1 of body weight, in 0.9% saline), and placed in a V-shaped plastic stand.…”