(1:00-1:15)
[8]: Patterns and thermoregulatory impacts of catastrophic molt in the northern elephant seal
Halley Carson†★§, Rachel Survilas, Heather Liwanag†§Department of Biological Sciences, †Frost Support, §Santa Rosa Creek Foundation Support, ★Speaker
Unlike most mammals, northern elephant seals (Mirounga angustirostris) exhibit an unusual physiological phenomenon known as a “catastrophic molt,” which involves the shedding of patches of skin and fur in the process of replacing their pelage annually. Remarkably, they undergo this energetically costly process while fasting. Our project will document the timing of the molt in different age classes of northern elephant seals and will provide novel information regarding how the catastrophic molt affects thermoregulation in these large marine endotherms. To do this, we will conduct ground surveys during the annual molt at the beaches of the Piedras Blancas elephant seal colony. Because adult females and juveniles haul out for their molt at a different time than the adult males, these surveys will document the phenology of the molt according to age class. To investigate how the molt affects thermoregulation, we will take infrared thermal images of the animals at different stages of the molt. These images will quantify the surface temperature of the animals across the body, before, during, and after the catastrophic molt. In addition, we will document abiotic weather factors, including air temperature, wind, and sunlight levels, to provide context for these thermal measurements. Data were collected for adult and subadult males during the 2024 summer field season and a molt code was created in order to document the molt progression. A range of skin surface temperatures was also determined. Currently, data collection is focusing on the pup molt, which we are contrasting with the male molt and will continue to analyze during the female and juvenile molt in the upcoming spring season. This will be the first study to document the timing and thermal consequences of the catastrophic molt in northern elephant seals. |
(1:15-1:30)
[9]: Polar Pelts: Morphology and Thermal Function of the Pelts of Weddell Seals
Stella Raymond†★, Dana Twisk, Allyson Taylor, Heather LiwanagDepartment of Biological Sciences, †Frost Support, ★Speaker
Mammals in polar regions are subjected to energetically demanding conditions and thus face a constant challenge to thermal homeostasis. Weddell seals (Leptonychotes weddellii) are the southernmost breeding mammal on Earth and therefore face extremely cold and windy conditions from birth. Like many phocid (true seal) species, Weddell seals are born with lanugo (neonatal fur) and no substantial blubber layer. Unlike many phocid pups, however, Weddell seals begin swimming in polar waters at around two weeks of age, often before they have fully molted their lanugo. Due to the high thermal conductivity of seawater relative to air, this is thermally challenging for young pups; indeed, Weddell seal pups with lanugo exhibit higher metabolic rates in water than in air. We hypothesized that the lanugo of Weddell seals would be morphologically distinct from adult pelage, and that these differences would make lanugo pelts superior insulators in air and in water, compared to adult pelts. To test this, we compared morphological characteristics (hair length, circularity, and density) of Weddell seal lanugo (n=6) and adult pelts (n=5), and we measured the thermal function (thermal resistance) of both pelt types in air and in water. We found that lanugo hairs were longer and more circular compared to adult hairs, and lanugo pelts had a higher fur density compared to adult pelts. As expected, both pelt types had reduced thermal resistance in water compared to air. Additionally, neonate pelts had higher thermal resistance than adult pelts in both conditions. These results demonstrate the importance of the lanugo coat for thermoregulation in Weddell seal pups, while they develop their blubber layer. This has implications for how climatic changes that accelerate melting of the fast ice, where Weddell seals breed, could impact pup energetics and survival |
(1:30-1:45)
[10]: Evaluation of the long-term safety of vagal and sacral nerve stimulation in Landrace pigs using neurobehavioral tests.
Benjamin Thall★, Kyle Mahon★, Magdalena MajDepartment of Biological Sciences, ★Speaker
The vagus nerve plays a crucial role in regulating digestion by stimulating the muscles of the digestive tract to contract and relax, while an impaired vagal nerve activity is associated with poor motility, potentially leading to gastroparesis, ulcerative colitis, and chronic constipation. The goal of this project was to evaluate the long-term safety of nerve stimulation in Landrace pigs using 3 different neurobehavioral tests.
Six 4-6 months-old female Landrace pigs were surgically inserted with electrodes and an implantable pulse generator (IPG) to stimulate vagus nerve (n=3 animals) or sacral nerves (n=3 animals). Vagus nerve and sacral nerve stimulation will occur at a low duty cycle (<10%) with a duration of 1hr/day for a month, compared to FDA-approved VNS/SNS therapies of 100% duty cycle for 24hr/day. Vagal nerve stimulation (VNS) and sacral nerve stimulation (SNS) is a validated method of modulating the muscle contraction rates in the stomach, colon, and pelvic floor.
We have mounted a set of cameras at the swine unit and worked as a team of 10 undergraduate students to design and conduct 3 neurobehavioral tests: human approach test, novel object recognition test, and an overall animal activity. Human approach test (HAT) measures fear and anxiety of animals, and involves evaluation of the animals’ distance, body position, and head orientation in relation to a stationary researcher. Novel object recognition (NOR) test measures once a week a short-term retention memory. Activity of animals is recorded 3 times a week during a 2-hour surveillance. All recorded videos are scored using Behavioral Observation Research Interactive Software (BORIS). The neurobehavioral tests are currently ongoing and will be statistically analyzed to evaluate the effect of the surgery (pre- and post-surgery) and neuromodulation (post-surgery and during-stimulation period). |
(1:45-2:00)
[11]: Polar Pelts: Morphology and Thermal Function of the Pelts of Weddell Seals
Stella Raymond†★, Dana Twisk, Allyson Taylor, Heather LiwanagDepartment of Biological Sciences, †Frost Support, ★Speaker
Mammals in polar regions are subjected to extreme conditions and thus face a constant challenge to thermal homeostasis. Weddell seals (Leptonychotes weddellii) are the southernmost breeding mammal on Earth and therefore face extremely cold and windy conditions from birth. Like many phocid (true seal) species, Weddell seals are born with lanugo (neonatal fur) and no substantial blubber layer. Unlike many phocid pups, however, Weddell seals begin swimming in polar waters at around two weeks of age, often before they have fully molted their lanugo. Due to the high thermal conductivity of seawater relative to air, this is thermally challenging for young pups; indeed, Weddell seal pups with lanugo exhibit higher metabolic rates in water than in air. We hypothesized that the lanugo of Weddell seals would be morphologically distinct from adult pelage, and that these differences would make lanugo pelts superior insulators in air and in water, compared to adult pelts. To test this, we compared morphological characteristics (hair length, circularity, and density) of Weddell seal lanugo (n=6) and adult pelts (n=5), and we measured the thermal function (thermal resistance) of both pelt types in air and in water. We found that lanugo hairs were longer and more circular compared to adult hairs, and lanugo pelts had a higher fur density compared to adult pelts. As expected, both pelt types had reduced thermal resistance in water compared to air. Additionally, neonate pelts had higher thermal resistance than adult pelts in both conditions. These results demonstrate the importance of the lanugo coat for thermoregulation in Weddell seal pups, while they develop their blubber layer. This has implications for how climatic changes that accelerate melting of the fast ice, where Weddell seals breed, could impact pup energetics and survival.
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(2:00-2:15)
[12]: MicrobiomeKG: Extracting Relationships between the Microbiome and Host Health from Published Supplementary Materials
Skye Goetz1★, Gwênlyn Glusman21 Department of Chemistry and Biochemistry, 2 Institute For Systems Biology, ★Speaker
The microbiome represents a complex community of trillions of microorganisms residing in various body parts, and plays critical roles in maintaining host health and well-being. Understanding the interactions between microbiota and host offers valuable insights into potential strategies to promote health, including microbiome-targeted interventions. We have created MicrobiomeKG, a Knowledge Graph for microbiome research, bridging various taxa and microbial pathways with host health. This novel knowledge graph derives algorithmically-generated knowledge assertions from the supplementary tables supporting published microbiome papers. By identifying knowledge assertions from supplementary tables, and expressing them as knowledge graphs, we are casting this valuable content into a format that is ideal for hypothesis generation. We present an example use case linking helminth infections with non-alcoholic fatty-liver disease via microbial taxa. MicrobiomeKG is deployed for integrative analysis and hypothesis generation, both programmatically and via the Biomedical Data Translator ecosystem. By bridging data gaps and facilitating the discovery of new biological relationships, MicrobiomeKG will help advance personalized medicine through a deeper understanding of the microbial contributions to human health and disease mechanisms. |
(2:15-2:30)
[13]: Farm evaluations of 4 lineages of the Pacific oyster Magallana gigas in California estuarine environments
Gillian Douglas★, Lexi Hollister, Skylar Wuelfing§, Shannon Baldwin, Faith Hanshaw, John Paneno, Tatum Schnider, Kristin Hardy, Kevin JohnsonDepartment of Biological Sciences, §Santa Rosa Creek Foundation Support, ★Speaker
As with all sectors of food production, changing environmental conditions pose a significant threat to Pacific oyster cultivation. These changing environmental conditions along with persistent disease pressures continue to have large impacts on survivorship and are driving selective breeding programs to minimize impacts to both survivorship and growth rates. In 2004, a new lineage of Pacific oysters was imported to the US West Coast from Southern Japan near the mouth of the Midori river. This new lineage has recently (since 2021) been integrated into breeding programs to increase genetic diversity and survival to pathogen stressors. Evaluating the efficacy of these breeding programs requires both on-farm and lab-based evaluations of performance across environments and abiotic conditions to reliably select for a commercially favored oyster. To better understand how each lineage performs, we monitored survivorship, growth rates, condition index, and shell shape in a multi-estuary farm study comparing commercially produced cohorts of the Midori, Miyagi, hybrid Midori and Miyagi, and triploid Pacific oyster lineages. This study was conducted in 3 oyster producing estuaries in California (Humboldt Bay, Tomales Bay, and Morro Bay) using standardized gear and monthly sampling. These findings are providing information to our farmer partners that is allowing them to make informed hatchery and planting decisions by identifying growth and survivorship traits of each lineage.
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(2:30-2:45)
[14]: Compatibility of eugenol anesthesia with classroom physiology experiments on nerve and muscle of frogs
Katherine Rees†★, Jason Blank†Department of Biological Sciences, †Frost Support, ★Speaker
Frogs serve as valuable model organisms for studying physiological responses of nerve, skeletal muscle, and heart in undergraduate biology labs. Induced hypothermia prior to pithing is the traditional method of euthanasia, but some veterinary guidelines discourage this practice and recommend chemical anesthesia instead. However, the most commonly used anesthetic, MS-222, is incompatible with physiology experiments. We sought an alternative anesthetic, and tested the hypothesis that eugenol anesthesia is compatible with classroom nerve and muscle experiments on frogs. Bullfrogs were euthanized after eugenol anesthesia or chilling. Additional groups were soaked in eugenol for extended durations of 30, 60, or 90 minutes beyond reflex loss. The sciatic nerve was stimulated while gastrocnemius force was measured using an isometric force transducer. The threshold voltage eliciting a muscle contraction and the peak isometric twitch force were recorded at 15 minute intervals for 2 hours. Isolated sciatic nerves were also evaluated to characterize anesthesia onset and recovery. Eugenol reliably induced loss of reflexes in 20 to 35 minutes. While eugenol increased threshold voltage and decreased force production, neuromuscular preparations maintained the ability to respond adequately to electrical stimulation, supporting its viability as an alternative anesthetic for classroom experiments. |