Search

BACKGROUND: Biodiversity is generally reduced when non-native species invade an ecosystem. Invasive crayfish, Procambarus clarkii, populate California freshwater streams, and in the Santa Monica Mountains (Los Angeles, USA), their introduction has led to trophic cascades due to omnivorous feeding behavior and a rapid rate of population growth. The native California newt, Taricha torosa, possesses a neurotoxin, tetrodotoxin (TTX), that affects freshwater animal behavior. Given P. clarkii has a limited evolutionary history with TTX, we hypothesized that TTX may affect crayfish feeding behaviors. To determine if TTX affects P. clarkii behavior, we measured cumulative movement and various feeding behaviors of P. clarkii exposed to (i) waterborne, ecologically realistic concentrations of TTX (~ 3.0 × 10- 8 moles/L), (ii) an anuran chemical cue to account for intraguild cues, or (iii) a T. torosa chemical cue with quantitated TTX in it (~ 6.2 × 10- 8 moles/L). RESULTS: We found that the presence of TTX in any form significantly reduced crayfish movement and decreased the amount of food consumed over time. Crayfish responses to the anuran treatment did not significantly differ from controls. CONCLUSION: Our laboratory results show that naturally occurring neurotoxin from native California newts limits invasive crayfish foraging and feeding rates, which may play a role in preserving local stream ecosystems by limiting invasive crayfish behaviors that are detrimental to biodiversity.

Extreme weather events are predicted to increase as a result of climate change, yet amphibian responses to extreme disturbance events remain understudied, especially in the Neotropics. Recently, an unprecedented windstorm within a protected Costa Rican rainforest opened large light gaps in sites where we have studied behavioral responses of diurnal strawberry poison frogs (Oophaga pumilio) to ultraviolet radiation for nearly two decades. Previous studies demonstrate that O. pumilio selects and defends perches where ultraviolet radiation (UV-B) is relatively low, likely because of the lethal and sublethal effects of UV-B. In this natural experiment, we quantified disturbance to O. pumilio habitat, surveyed for the presence of O. pumilio in both high-disturbance and low-disturbance areas of the forest, and assessed UV-B levels and perch selection behavior in both disturbance levels. Fewer frogs were detected in high-disturbance habitat than in low-disturbance habitat. In general, frogs were found vocalizing at perches in both disturbance levels, and in both cases, in significantly lower UV-B levels relative to ambient adjacent surroundings. However, frogs at perches in high-disturbance areas were exposed to UV-B levels nearly 10 times greater than males at perches in low-disturbance areas. Thus, behavioral avoidance of UV-B may not reduce the risks associated with elevated exposure under these novel conditions, and similarly, if future climate and human-driven land-use change lead to sustained analogous environments.

Large-scale digital flu vaccine campaigns have experienced difficulty increasing vaccination coverage among African Americans and Hispanics, and are routinely inundated by negative responses from vaccine opponents. A digital campaign employing user-generated content from social media 'micro' influencers who are predominantly followed by African Americans and Hispanics was implemented during the 2018-19 and 2019-20 flu seasons to disseminate positive information about the flu vaccine. At the time, this constituted the largest influencer-driven health campaign focused on these communities in the United States. Comments on posts were qualitatively coded to determine content perceptions among those exposed to posts. Digital metrics were also analyzed. During Year 1, posts reached 9 million+ social media users and generated 64 612 likes or shares, and 1512 responses. In Year 2, posts reached 8 million+ users and generated 155 600 likes or shares, and 3122 responses. Around 94% of public responses to posts were positive, suggesting this is a promising strategy to communicate health information and could shift social norms, particularly for heavily debated topics such as vaccination. This strategy represents a more community-led and participatory approach than most large-scale vaccination campaigns have attempted, with immediate applicability to communications about the COVID-19 vaccine.

During inner ear semicircular canal morphogenesis in zebrafish, patterned canal-genesis zones express genes for extracellular matrix component synthesis. These include hyaluronan and the hyaluronanbinding chondroitin sulfate proteoglycan Versican, which are abundant in the matrices of many developing organs. Charged hyaluronate polymers play a key role in canal morphogenesis through osmotic swelling. However, the developmental factor(s) that pattern the synthesis of the matrix components and regulation of hyaluronate density and swelling are unknown. Here, we identify the transcription factor Lmx1b as a positive transcriptional regulator of hyaluronan, Versican, and chondroitin synthesis genes crucial for canal morphogenesis. We show that Versican regulates hyaluronan density through its protein core, whereas the charged chondroitin side chains contribute to the hydration of hyaluronate-containing extracellular matrices. Versican-tuned properties of hyaluronate matrices may be a broadly used mechanism in morphogenesis with important implications for understanding diseases in which these matrices are impaired, and for hydrogel engineering for tissue regeneration. [ABSTRACT FROM AUTHOR]

Occupational noise exposure continues to be a prevalent hazard in many industries. While the proliferation of noise dosimeters and wearable devices has made it easier to assess a worker's exposure to noise, many employees exposed to hazardous (i.e., >85 dBA) levels of noise may go their entire career without ever having their personal noise levels measured. In contrast to other occupational exposures, noise is easily perceived by the individual exposed, allowing them to develop subjective judgments regarding its characteristics. To determine whether such self-reported exposures to occupational noise are associated with hearing loss, this analysis used audiometric data and self-reported occupational exposure to loud noise from the National Health and Nutrition Examination Survey (NHANES), which has collected such data from 1999 to May 2020. Linear and logistic regressions models found a statistically significant association between self-reported noise exposure and worsened hearing at the 3, 4, 6, and 8 kHz hearing frequency as well as an elevated odds ratio for the development of hearing loss greater than 25 dB at the 2, 3, and 4 kHz audiometric frequencies. The results of this analysis suggest that in the absence of exposure measurements, workers are likely able to detect exposure to hazardous levels of noise. In these instances, additional measurements should be collected to determine if the workers should be enrolled in a hearing conservation program. [ABSTRACT FROM AUTHOR]

Recent studies indicate that FoxO transcription factors play an important role in promoting muscle atrophy. To study mechanisms mediating effects of FoxO proteins on muscle wasting, FoxO1estrogen receptor fusion proteins that are activated by treatment with 4-hydroxytamoxifen (4-OH-T) were stably transfected in [C.sub.2][C.sub.12] skeletal myoblasts using the pBABE retroviral system and grown into multinucleated skeletal myotubes. Activation of FoxO1 resulted in significant muscle atrophy, which was accompanied by DNA fragmentation, evidenced by terminal deoxynucleotidyl transferase dUTP-mediated nick end labeling. Cells expressing a DNA-binding-deficient form of FoxO1 also exhibited significant atrophy on FoxO1 activation but no hallmark signs of apoptosis. FoxO1 activation resulted in a significant increase in muscle atrophy F-box (MAFbx)/atrogin-1, muscle-specific RING finger protein 1 (MuRF-1), and Bcl-2-interacting mediator of cell death (Bim) gene expression, with no significant increase in Bcl-2/adenovirus E1B 19-kDa-interacting protein 3 (BNip3) gene expression. Although the ability of FoxO1 to induce MuRF-1 gene expression appeared to be independent of DNA binding, expression of MAFbx/atrogin-1 and Bim was significantly blunted in cells expressing DNA-binding-deficient FoxO1. BNip3 gene expression was significantly elevated in DNA-binding-deficient mutant cells. These findings indicate that FoxO1 promotes skeletal muscle atrophy through induction of proteolytic and apoptotic machinery via DNA-binding-dependent and -independent mechanisms. atrophy; MAFbx/atrogin-1; Bim; BNip3; terminal deoxynucleotidyl transferase dUTP-mediated nick end labeling

Anti-inflammatory strategies are often used to reduce muscle pain and soreness that can result from high-intensity muscular activity. However, studies indicate that components of the acute inflammatory response may be required for muscle repair and growth. The hypothesis of this study was that cyclooxygenase (COX)-2 activity is required for compensatory hypertrophy of skeletal muscle. We used the synergist ablation model of skeletal muscle hypertrophy, along with the specific COX-2 inhibitor NS-398, to investigate the role of COX-2 in overload-induced muscle growth in mice. COX-2 was expressed in plantaris muscles during compensatory hypertrophy and was localized mainly in or near muscle cell nuclei. Treatment with NS-398 blunted the increases in mass and protein content in overloaded muscles compared with vehicle-treated controls. Additionally, the COX-2 inhibitor decreased activity of the urokinase type plasminogen activator, macrophage accumulation, and cell proliferation, all of which are required for hypertrophy after synergist ablation. Expression of insulin-like growth factor-1 and phosphorylation of Akt, mammalian target of rapamycin, and p70S6K were increased following synergist ablation, but were not affected by NS-398. Additionally, expression of atrogin-1 was reduced during hypertrophy, but was also not affected by NS-398. These results demonstrate that COX-2 activity is required for skeletal muscle hypertrophy, possibly through facilitation of extracellular protease activity, macrophage accumulation, and cell proliferation. inflammation; nonsteroidal anti-inflammatory drug; macrophage; muscle growth

Date Presented 03/23/24 The objective is to examine the preexisting deidentified data from a driver rehabilitation program to determine human factors (vision, motor, and cognition) that contribute to driving performance. Primary Author and Speaker: Michael D. Justiss Additional Authors and Speakers: Katie Faulk, Bailee Schroeder, Warren Wall, Sierra Smith [ABSTRACT FROM AUTHOR]

Date Presented 03/22/24 Embedding practice scholarship in daily work is challenging for practitioners despite being emphasized in the American Occupational Therapy Assocation's Vision 2025 and mission statements. This presentation defines and provides strategies used by active practice scholars. Primary Author and Speaker: Sierra Rose Smith Additional Authors and Speakers: Adriana Macdonald Contributing Authors: Patricia Crist, Rebekah Givens, Taylor Stringer [ABSTRACT FROM AUTHOR]