Ecological correlates of species' roles in highly invaded seed dispersal networks.

Ecosystems with a mix of native and introduced species are increasing globally as extinction and introduction rates rise, resulting in novel species interactions. While species interactions are highly vulnerable to disturbance, little is known about the roles that introduced species play in novel interaction networks and what processes underlie such roles. Studying one of the most extreme cases of human-modified ecosystems, the island of O'ahu, Hawaii, we show that introduced species there shape the structure of seed dispersal networks to a greater extent than native species. Although both neutral and niche-based processes influenced network structure, niche-based processes played a larger role, despite theory predicting neutral processes to be predominantly important for islands. In fact, ecological correlates of species' roles (morphology, behavior, abundance) were largely similar to those in native-dominated networks. However, the most important ecological correlates varied with spatial scale and trophic level, highlighting the importance of examining these factors separately to unravel processes determining species contributions to network structure. Although introduced species integrate into interaction networks more deeply than previously thought, by examining the mechanistic basis of species' roles we can use traits to identify species that can be removed from (or added to) a system to improve crucial ecosystem functions, such as seed dispersal.

Mechanisms underlying interaction frequencies and robustness in a novel seed dispersal network: lessons for restoration.

As human-caused extinctions and invasions accumulate across the planet, understanding the processes governing ecological functions mediated by species interactions, and anticipating the effect of species loss on such functions become increasingly urgent. In seed dispersal networks, the mechanisms that influence interaction frequencies may also influence the capacity of a species to switch to alternative partners (rewiring), influencing network robustness. Studying seed dispersal interactions in novel ecosystems on O'ahu island, Hawai'i, we test whether the same mechanisms defining interaction frequencies can regulate rewiring and increase network robustness to simulated species extinctions. We found that spatial and temporal overlaps were the primary mechanisms underlying interaction frequencies, and the loss of the more connected species affected networks to a greater extent. Further, rewiring increased network robustness, and morphological matching and spatial and temporal overlaps between partners were more influential on network robustness than species abundances. We argue that to achieve self-sustaining ecosystems, restoration initiatives can consider optimal morphological matching and spatial and temporal overlaps between consumers and resources to maximize chances of native plant dispersal. Specifically, restoration initiatives may benefit from replacing invasive species with native species possessing characteristics that promote frequent interactions and increase the probability of rewiring (such as long fruiting periods, small seeds and broad distributions).

E6 proteins from high-risk HPV, low-risk HPV, and animal papillomaviruses activate the Wnt/ß-catenin pathway through E6AP-dependent degradation of NHERF1.

High-risk human papillomavirus (HPV) E6 proteins associate with the cellular ubiquitin ligase E6-Associated Protein (E6AP), and then recruit both p53 and certain cellular PDZ proteins for ubiquitination and degradation by the proteasome. Low-risk HPV E6 proteins also associate with E6AP, yet fail to recruit p53 or PDZ proteins; their E6AP-dependent targets have so far been uncharacterized. We found a cellular PDZ protein called Na+/H+ Exchanger Regulatory Factor 1 (NHERF1) is targeted for degradation by both high and low-risk HPV E6 proteins as well as E6 proteins from diverse non-primate mammalian species. NHERF1 was degraded by E6 in a manner dependent upon E6AP ubiquitin ligase activity but independent of PDZ interactions. A novel structural domain of E6, independent of the p53 recognition domain, was necessary to associate with and degrade NHERF1, and the NHERF1 EB domain was required for E6-mediated degradation. Degradation of NHERF1 by E6 activated canonical Wnt/ß-catenin signaling, a key pathway that regulates cell growth and proliferation. Expression levels of NHERF1 increased with increasing cell confluency. This is the first study in which a cellular protein has been identified that is targeted for degradation by both high and low-risk HPV E6 as well as E6 proteins from diverse animal papillomaviruses. This suggests that NHERF1 plays a role in regulating squamous epithelial growth and further suggests that the interaction of E6 proteins with NHERF1 could be a common therapeutic target for multiple papillomavirus types.

Fertility and pregnancy outcomes in primary hyperparathyroidism: Observations from a large insured population.

CONTEXT: Primary hyperparathyroidism (PHPT) has initially been implicated in adverse maternal and neonatal outcomes, while subsequent population studies have failed to show an association. OBJECTIVE: To compare maternal, pregnancy, and neonatal outcomes in patients with and without PHPT. DESIGN: Retrospective matched-cohort study (2005-2020). SETTING: An integrated healthcare delivery system in Southern California. PATIENTS: Women aged 18-44 years were included. Patients with biochemical diagnosis of PHPT were matched 1:3 with eucalcemic controls (non-PHPT). MAIN OUTCOME MEASURES: Achievement of pregnancy, pregnancy outcomes (including rates of abortion, maternal complications), and neonatal outcomes (including hypocalcemia, need for intensive care). RESULTS: The cohort comprised 386 women with PHPT and 1158 age-matched controls. Pregnancy rates between PHPT and control groups were similar (10.6% vs 12.8%). The adjusted rate ratio of pregnancy was 0.89 (95% CI: 0.64-1.24) (PHPT vs non-PHPT). Twenty-nine pregnancies occurred in women with co-existing PHPT and 191 pregnancies occurred in controls, resulting in 23 (79.3%) and 168 (88.0%) live births, respectively (p=0.023). Neonatal outcomes were similar. Live birth rates were similar (86.4%, 80%, 79.2%) for those undergoing parathyroidectomy prior (n=22), during (n=5), or after pregnancy/never (n=24). Among patients who underwent parathyroidectomy during pregnancy, no spontaneous abortions occurred in women entering pregnancy with peak calcium <11.5 mg/dL [2.9 mmol/L]. CONCLUSIONS: We observed no difference in pregnancy rates between women with or without PHPT. Performing parathyroidectomy before pregnancy or during the second trimester appears to be a safe and successful strategy, and adherence to this strategy may be most critical for patients with higher calcium levels (≥11.5 mg/dL [2.9 mmol/L]).

Exploitation competition between seed predators and dispersers introduced to Hawaiian forests.

Exploitation competition occurs when one group of organisms reduces the availability of a resource for another group of organisms. For instance, plants produce a certain number of fruits for seed dispersal by fruit-eating animals (hereafter frugivores), and fruit consumption by one group of frugivores can reduce the number of fruits available for other frugivores. However, it is uncertain whether exploitation competition is common among frugivores, particularly in novel ecosystems, where food resources are generally thought to be abundant and invasive species are dietary generalists. In a novel ecosystem in Hawai'i, we used gut passage experiments with captive birds to identify roles of introduced frugivores and found they were either distinctly seed dispersers or predators. We then experimentally tested how frugivory by seed predators influenced frugivory by seed dispersers. Specifically, we used exclosures around fruiting plants that blocked seed predator access, while permitting seed disperser access, and we had two control treatments that allowed for access by all frugivores (n = 139 plants). When seed predators were excluded from plants, there was more frugivory by dispersers compared to controls, and results varied by year and plant species. Overall, we show that introduced frugivores occupied distinct ecological roles (seed predator or seed disperser), exploitation competition occurred between these introduced frugivore groups, and seed predators had both direct (via seed destruction) and indirect (via reduction in frugivory by dispersers) effects on seed dispersal. Thus, in this novel ecosystem, multiple frugivory is subtractive, and competition for fruit between introduced seed predators and seed dispersers scales up to affect invasions and the conservation of native flora.

Demographic and clinical characteristics of dominican adults admitted to a diabetic foot clinic in the Dominican Republic, 2015.

AIM: To identify the demographic and clinical characteristics of Dominican adults admitted to a diabetic foot clinic and compare these characteristics by sex to better characterize and understand the severity of diabetes in the Dominican Republic. METHODS: We conducted a retrospective medical chart review of Dominican adults admitted to the National Institute of Diabetes, Endocrinology, and Nutrition's (INDEN) diabetic foot clinic between January 1st, 2015 and December 31st, 2015. We generated descriptive statistics and compared results by sex. RESULTS: We assessed 447 medical charts of patients admitted in 2015. More men visited the clinic than women (65% vs. 35%). The average duration of diabetes was 14.4 ±â€¯8.9 years. Abscess was the most common foot problem (74% in men, 68% in women, p = 0.164). A slightly smaller proportion of men received amputations than women (46% vs. 51%, p = 0.390). Women were older (p < 0.001), less educated (p = 0.004), and less likely to be married (p < 0.001). Women also exhibited higher rates of obesity (p = 0.003), hypertension (p = 0.005), cardiovascular disease (p = 0.011), ischemic foot (p = 0.008), and above the knee amputations (p = 0.002). CONCLUSION: Implementation of diabetes education programs, introduction of proper foot care, and improved resources for lifestyle management are needed to increase awareness and subsequently decrease diabetes and its negative impact on the health and economy of the Dominican Republic. Our findings suggest that various risk factors and comorbidities important to the development of diabetes may be disproportionately affecting women. Interventions should focus on women and their behaviors that increase risk for diabetes.

Age and performance at fledging are a cause and consequence of juvenile mortality between life stages.

Should they stay or should they leave? The age at which young transition between life stages, such as living in a nest versus leaving it, differs among species and the reasons why are unclear. We show that offspring of songbird species that leave the nest at a younger age have less developed wings that cause poorer flight performance and greater mortality after fledging. Experimentally delayed fledging verified that older age and better developed wings provide benefits of reduced juvenile mortality. Young are differentially constrained in the age that they can stay in the nest and enjoy these fitness benefits because of differences among species in opposing predation costs while in the nest. This tension between mortality in versus outside of the nest influences offspring traits and performance and creates an unrecognized conflict between parents and offspring that determines the optimal age to fledge.