Tactic-specific antimicrobial activity suggests a parental care function for accessory glands in a marine toadfish.

Males of some species possess extra reproductive organs called accessory glands which are outgrowths of the testes or sperm duct. These organs have a well-established role in reproduction; however, they also appear to have other important functions that are less understood. Here, we investigate the function of the highly complex accessory glands of a marine toadfish, Porichthys notatus, a fish with two reproductive male types: large care-providing 'guarder' males and small non-caring 'sneaker' males. While both male types have accessory glands, guarder male accessory glands are much larger relative to their body size. We show that accessory gland fluids strongly inhibit the growth of bacterial genera associated with unhealthy eggs and have no effect on the growth of strains isolated from healthy eggs. This antibacterial effect was particularly pronounced for extracts from guarder males. Furthermore, we demonstrate that both healthy and unhealthy plainfin midshipman eggs have diverse but distinct microbial communities that differ in their composition and abundance. The highly specific inhibitory capacity of accessory gland fluid on bacteria from unhealthy eggs was robust across a wide range of ecologically relevant temperatures and salinities. Collectively, these ecological and molecular observations suggest a care function for the accessory gland mediated by antimicrobial agents.

Sperm maturation and male tactic-specific differences in ejaculates in the plainfin midshipman fish Porichthys notatus.

Using the plainfin midshipman fish Porichthys notatus, a species with alternative reproductive tactics (ARTs), we investigated how sperm maturation shapes sperm competitive abilities. We compared sperm performance and morphology before and after final sperm maturation by sampling sperm from the testes and stripped ejaculates of guarders and sneakers. In accordance with sperm competition risk theory, ejaculates from sneaker males had three times as much sperm as ejaculates from guarder males and sneaker males produced faster swimming sperm than guarder males, but this was only the case after final sperm maturation had occurred. Additionally, fully mature sperm found in ejaculates had larger heads and midpieces than sperm found in the testes. These results emphasize the important role played by non-sperm components of an ejaculate in mediating sperm performance and potentially also morphology.

Sectional neuroanatomy of the lumbosacral spine (L1-S5).

This paper will review the lumbosacral spine (L1-S5). Procedures performed in the lumbosacral spine include electromyography, spinal stimulator implants, spinal infusion implants for spasticity or pain medications, sacroiliac spine injections, facet blocks, and steroid injections. Complications from these procedures include iatrogenic paraplegia or paraplegia due to transverse myelitis, intravascular penetration, dural puncture, increased pain at the injection site, increased radicular pain, increased spine pain, lightheadedness, nausea, nonspecific headache, and vomiting. Long-term complications include implant infection, implant or catheter dislodgment/kinking, and device failure. This paper provides anatomically accurate schematics of innervations of the lumbosacral spine (L1-S5) that can be used to interpret magnetic resonance images of the muscles and nerves. Cross-sectional schematics of the lumbosacral spine were drawn as they appear on imaging projections. The relevant nerves were color coded. The muscles and skin surfaces were labeled and assigned the color of the appropriate nerves. An organized comprehensive map of the motor innervation of the lumbosacral spine allows the physician to increase the accuracy and efficacy of interventional procedures. This anatomical map could also assist the electromyographer in correlating the clinical and electrophysiological findings on magnetic resonance images.