American Samoan Research Articles

A group prenatal care intervention reduces gestational weight gain and gestational diabetes in American Samoan women.

The objective of this study was to determine the preliminary effectiveness of an intervention to mitigate adverse pregnancy outcomes associated with pre-pregnancy obesity in American Samoa. We enrolled n = 80 low-risk pregnant women at <14 weeks' gestation. A complete case analysis was conducted with randomized group assignment (group prenatal care-delivered intervention vs. one-on-one usual care) as the independent variable. Primary outcomes were gestational weight gain and postpartum weight change. Secondary outcomes included gestational diabetes screening and exclusive breastfeeding at 6 weeks post partum. Other outcomes reported include gestational diabetes incidence, preterm birth, mode of birth, infant birth weight, and macrosomia. Gestational weight gain was lower among group versus usual care participants (mean [SD], 9.46 [7.24] kg vs. 14.40 [8.23] kg; p = 0.10); postpartum weight change did not differ between groups. Although the proportion of women who received adequate gestational diabetes screening (78.4% group; 65.6% usual care) was similar, there were clinically important between-group differences in exclusive breastfeeding (44.4% group; 25% usual care), incidence of gestational diabetes (27.3% group; 40.0% usual care), and macrosomia (8.3% group; 29.0% usual care). It may be possible to address multiple risk factors related to intergenerational transmission of obesity in this high-risk setting using a group care-delivered intervention.

'Tausi Feagaiga: A Project to Train Caregivers and Empower the American Samoan Community.

The 'Tausi Feagaiga (Covenant Keeper) project was a partnership to support the traditional values of tausi matua (caring for one's elders). The partners included a non-governmental organization (Pacific Youth and Community Development), a faith-based organization (Roman Catholic Diocese of Samoa-Pago Pago), and an institute of higher education (University of Hawai'i John A. Burns School of Medicine). The project was created to address the lack of community-based health care such as home health or hospice, and families needing to work outside the home. A culturally based caregiving curriculum was developed to educate caregivers and improve their knowledge and skills. Using a train-the-trainer model, 125 caregivers were trained in family caregiving from 2016-2020. Training was conducted through an intensive workshop followed by practicum at Hope House, the Catholic Diocese home for the aged. Participants who expressed a willingness and competency were mentored to be trainers to continue the 'Tausi Feagaiga project. The mean self-rated confidence in caregiving improved significantly from 3.17 ± 1.02 (mean SD) pre workshop to 3.53 ± 0.71 post workshop (P = .001). Competence in geriatric syndromes was improved from 18.04 ± 4.27 to 21.31 ± 4.30 after attending the workshop (P < .001) and the feedback was extremely positive. Technical assistance was provided to obtain funding through American Samoa Medicaid State Agency to improve the existing infrastructure of Hope House, obtain much needed supplies, and increase ability to hire the participants. 'Tausi Feagaiga positively impacted the lives of the residents of Hope House, the course participants, the elders in the community, and those who care for them.

O le tagata ma lona aiga, o le tagata ma lona fa’asinomaga (Every person belongs to a family and every family belongs to a person): Development of a parenting framework for adolescent mental wellbeing in American Samoa

American Samoan adolescents experience a high prevalence of mental health problems, including depression, anxiety, substance use, and suicidal thoughts and behaviors. To complement existing health system efforts, family-based interventions may be a feasible, cost-effective, and relevant opportunity to promote mental health. This community-partnered, qualitative study aimed to: (1) identify potential family-related psychosocial protective factors for adolescent mental health and (2) develop a framework for a parenting program to promote adolescent mental health in American Samoa. Applying the fa’afaletui framework developed for research in Samoan communities, which emphasizes the importance of weaving a range of community member perspectives to reach consensus, semi-structured in-depth interviews with adult key informants (n = 28) were conducted between October 2020 and February 2021. Results were validated through five focus groups with Samoan adolescents (n = 35) between May and June 2022. Adult participants were sampled for diversity in profession, age, gender, education, and region of residence; adolescent participants were sampled for diversity in gender. Participants were recruited using personal networks and snowball sampling; adolescent participants also responded to Facebook advertising. The semi-structured interviews focused on broad topics including common mental health problems, contributors to mental illness, and potential interventions, among others. Transcripts were coded in duplicate and analyzed using deductive thematic analysis. Themes were collaboratively mapped onto an adapted fonofale model, an existing framework for Pacific Island health research. Six themes described key practices: (1) provide emotional safety and security; (2) provide physical safety and security; (3) encourage sense of self; (4) strengthen intergenerational communication skills; (5) prioritize quality time; and (6) cultivate healthy coping strategies. Participants also expressed the importance of a supportive environment grounded in culture, family and community, and caregiver mental health. These results provide an initial step to identify family-focused factors that promote adolescent mental health in American Samoa and categorize them into a framework to inform intervention development. Drawing on a collaborative and community-partnered process, these findings provide the first evidence-based framework to develop a parenting program to promote adolescent mental wellbeing and resilience in Samoan communities.

Utilizing Respondent Driven Sampling to assess neurocognitive functioning in the indigenous American Samoa population 60 years or older.

AbstractBackgroundRespondent Driven Sampling (RDS) is a cost‐efficient, chain referral sampling method, where respondent seeds recruit others who are eligible within their social networks; those recruited by the seeds then recruit others (Heckathorn, 1997). In American Samoa recruitment of a random population‐based sample is difficult due to systematic error and biases in sample characteristics arising from the hierarchical relationships prominent in American Samoan society (Aitaoto, et al. 2007; Cassel 2010; Cassel, 2014). The INdigenous Samoan Partnership to Initiate Research Excellence (INSPIRE) program recruited 718 participants age 45 and over during a 51‐day period with 20% age 60 or higher. For this reason, RDS methods were utilized to assess neurocognitive functioning in the Samoan population age 60 or over.MethodINSPIRE program staff recruited 60 participants as RDS seeds (30 men and 30 women). Once the seeds completed the data collection process, they were given coupons to recruit a maximum of 3 community members. In addition, they were provided a printed reminder of the eligibility criteria. The patterned continued to create consecutive recruitment waves (Wave 1, n = 60; Wave 2, n = 180; Wave 3, n = 540) until the sample size was reached. Participants received a total $25 incentive for participating in the survey. Additionally, participants will be compensated as RDS recruiters and receive an additional $15 for each recruit who participates, up to a maximum of 3. The RDS recruitment proposed to yield 780 participants, with 390 women and 390 men with a 12% loss to follow up.ResultPreliminary data analysis reveals target sample size was collected in 126 days (41% Male, 59% Female). Referral chain analysis reports only 25% of seeds recruited 80% of participants although social networking sizes varied for the seeds. Some participants with higher social networks did not participate in recruiting.ConclusionIntercept promotions complimented the use of RDS to help identify seeds and include faith‐based institutions (churches), senior centers, civics clubs, village‐based and other networks to recruit men and women, ages 60 and over. Maintaining a central location for study implementation and coupon payment supported ease of access for the study population.

Abstract P6-05-32: Does Aggregation Hide Place of Death Disparities for Asians with Breast Cancer?

Abstract Introduction: Place of death (PoD) studies are often used to motivate and monitor progress on health inequities for persons with cancer. It remains unclear whether aggregation of Asian race masks disparities in health equity for care at the end of life. Methods: De-identified death certificate data were obtained via the National Center for Health Statistics. All adult (&amp;gt;18 years of age) breast cancer deaths from 2018 to 2019 were included. Multinomial logistic regression was used to test for differences in place of death associated with sociodemographic variables. Results: From 2018 through 2019, 81,772 died from breast cancer in the United States. Overall, persons of Asian descent were less likely to die at home compared to White patients. Disaggregation noted significant differences in likelihood of hospice facility use. For example, Filipino race was approximately 5 times more likely to utilize hospice facilities (CI 3.764, 8.718; p&amp;lt; 0.001) compared to Whites, whereas Chinese race was significantly less likely (OR 0.49, 95% CI 0.307 to 0.627, p&amp;lt; 0.001). American Indian (OR 0.006), Asian Indian (OR 0.016), and Samoan (0.011) were the least likely to die in a nursing facility. While trends were overall similar when compared to White, Black and Hispanics, the likelihood of PoD among Asian subgroups were significantly different. Conclusion: Our data highlights notable differences in PoD only apparent with disaggregation of Asian race. While this study remains exploratory in nature, and reasons to explain these disparities are necessary, disaggregation of the Asian Pacific Island category is imperative to unmask disparities to improve health equity among all indigenous populations. Association Between Race and Place of Death for Patients with Breast Cancer Table 1. Number of deaths due to breast cancer in 2018 and 2019, by race. Odds ratios for the association between race and place of death from multinomial regression. Citation Format: Naveena Lall, Alexandra Noveihed, Qasim S. Hussaini, Amanda L. Blackford, Arjun Gupta, Ramy Sedhom. Does Aggregation Hide Place of Death Disparities for Asians with Breast Cancer? [abstract]. In: Proceedings of the 2022 San Antonio Breast Cancer Symposium; 2022 Dec 6-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2023;83(5 Suppl):Abstract nr P6-05-32.

Validation of the Short-Test of Functional Health Literacy in Adults for the Samoan Population.

Background:Health literacy encompasses various levels of communication for an individual, provider, and an organization. Validated and reliable tools have been developed to assess health literacy; however, there is a paucity of tools available to assess health literacy in native languages for indigenous and racial/ethnic minority populations.Objective:This article shares the process taken to translate and evaluate validation and reliability of the Short Test of Functional Health Literacy in Adults for use with the Samoan population.Methods:Respondent-driven sampling was used to collect data from 1,543 adults age 45 years and older in American Samoa. A confirmatory factor analysis using a two-factor model for validation was conducted.Key Results:The validation results indicated a “good fit” in multiple indices and Cronbach's alpha indicated high internal consistency in both the English and Samoan languages.Conclusions:Developing culturally validated and reliable health literacy assessment tools is important to help health care professionals decrease health disparities and address inadequate health literacy in all cultures. [HLRP: Health Literacy Research and Practice. 2022;6(4):e247–e256.]Plain Language Summary:The INSPIRE project studied the Short Test of Functional Health Literacy in Adults (STOFHLA) tested on the American Samoan population age 50 years and older. The results would show if the STOFHLA is a valid tool to measure functional health literacy in American Samoa adults.

Exploring the Impact of Dementia in Samoan Culture: A Qualitative Study on Community Perspective

ABSTRACT Purpose: Explore if and how American Samoan cultural norms influence caregivers’ knowledge, attitudes, and care choices for person’s living with Alzheimer’s Dementia (AD).Design: This pilot study used mixed methods.Methods: 1) Quantitative survey: measuring knowledge/attitudes towards AD (n = 80); 2) Qualitative techniques: a) Focus groups (n= 54) with caregivers; b) Semi-structured interviews (n=26) with health professionals; and c) In-depth interviews (n=3) with key informants. Emergent themes were created using data from all methods.Findings: Quantitative analyses revealed 50% of participants identified AD as normal aging, 83% as mental illness. The majority of participants believed elders with AD do not experience pain (70%) and should be cared for solely at home (74%). Qualitative evidence showed dissonance between cultural norms of respect for elders, familial caregiving duty, shame in others observing elders’ dementia-related behaviours, and the current language used to describe AD.Conclusions: Our findings show a need for developing and disseminating culturally sensitive terminology for AD to destigmatize and transmute attitudes, knowledge and care choices for elders living with AD.Clinical Evidence: American Samoan terminology for dementia is discordant with its cultural norms, thus shaping caregivers’ perceptions of AD and influencing care choices for managing AD symptoms.

Genetic epidemiology of lymphatic filariasis in American Samoa after mass drug administration

Over 892 million people in 48 countries are at risk of infection by nematodes that cause lymphatic filariasis. As part of the Global Programme to Eliminate Lymphatic Filariasis, mass drug administration is distributed to communities until surveillance indicates infection rates are below target prevalence thresholds. In some countries, including American Samoa, lymphatic filariasis transmission persists despite years of mass drug administration and/or has resurged after cessation. Nothing is known about the population genetics of Wuchereria bancrofti worms in Polynesia, or whether local transmission is persisting and/or increasing due to inadequate mass drug administration coverage, expansion from residual hotspots, reintroduction from elsewhere, or a combination. We extracted DNA from microfilariae on blood slides collected during prevalence surveys in 2014 and 2016, comprising 31 pools of five microfilariae from 22 persons living in eight villages. We sequenced 1104 bp across three mitochondrial markers (ND4, COI, CYTB). We quantified parasite genetic differentiation using variant calls and estimated haplotypes using principal components analysis, F-statistics, and haplotype networks. Of the variants called, all but eight were shared across the main island of Tutuila, and three of those were from a previously described hotspot village, Fagali’i. Genotypic data did not support population genetic structure among regions or villages in 2016, although differences were observed between worms collected in Fagali’i in 2014 and those from 2016. Because estimated haplotype frequency varied between villages, these statistics suggested genetic differentiation, but were not consistent among villages. Finally, haplotype networks demonstrated American Samoan sequence clusters were related to previously published sequences from Papua New Guinea. These are, to our knowledge, the first reports of W. bancrofti genetic variation in Polynesia. The resurgent parasites circulating on the main island of American Samoa represent a single population. This study is the first step towards investigating how parasite population structure might inform strategies to manage resurgence and elimination of lymphatic filariasis.

Growth and maturation of three commercially important coral reef species from American Samoa

This study presents age-based life history information on three small-bodied species targeted in the American Samoan fishery: Chlorurus japanensis palecheek parrotfish/fuga-alosama, Lethrinus rubrioperculatus spotcheek emperor/fiola pa`o`omumu, and Naso lituratus orangespine unicornfish/ili`ilia. Age and reproductive information were derived from sagittal otoliths and gonads. Maximum observed ages were 7 years for C. japanensis, 10 years for L. rubrioperculatus, and 25 years for N. lituratus. Due to a limited numbers of immature samples, a proxy for size at 50% maturity (L50) was derived from the relationship between asymptotic fork length (L∞) and L50 based on data published for species from similar geographic regions and respective families. L50 was estimated at 20.9 cm for C. japanensis, 20.4 cm for L. rubrioperculatus, and 17.5 cm for N. lituratus. Derived estimates were within 1 % of the L50 calculated for C. japanensis and N. lituratus from the limited number of immature samples collected in this study, indicating that for regions where sampling ability is limited, derived relationships between L∞ and L50 can be used to calculate an appropriate proxy. Naso lituratus demonstrated a biphasic mortality schedule with a higher than expected total mortality rate in the first 7 years of life. The age-based demographic information presented here can be used for future stock assessments and ecosystem models, which should facilitate improved management.

Diabetes Prevention for Pacific People in the United States: A Mixed-Methods Feasibility Study to Adapt the Diabetes Prevention Program With Samoan/Tongan Church Communities.

To determine baseline characteristics of a group of Samoans/Tongans in Southern California at risk for type 2 diabetes mellitus and identify barriers, cultural factors, and readiness and capacity to implement a culturally tailored Diabetes Prevention Program (DPP) in a faith-based setting. A mixed-methods pilot that included piloting modified DPP sessions, conducting a survey, and focus groups (N = 4). Samoan/Tongan faith-based organizations. Samoan/Tongan church members in Southern California who were interested in lifestyle behavior change. Surveys assessing sociodemographic, acculturation, health status, food insecurity, and psychosocial factors. Focus groups focusing on attitudes toward the curriculum, opportunities for tailoring, and specific barriers/facilitators for healthy weight, nutrition, and physical activity. Participants (N = 47) were on average 42 years old, female (57%), and identified as Pacific Islander (35% Samoan, 30% American Samoan, and 35% Tongan). Ninety-eight percent of respondents were overweight/obese, and 45% of households were food insecure. Less than half of respondents were born in the United States, and 28% reported "poor" or "fair" English proficiency. Those with higher body mass indexes were more likely to score lower on internal locus of control and self-efficacy for healthy eating and were motivated to lose weight to feel in control of their health. Focus group results revealed that members of the Samoan/Tongan communities are "underserved" and experience a lack of culturally relevant programs to address obesity and chronic disease. Several barriers to healthier lifestyles were identified including adaptation of traditional recipes made in the United States (ie, to be less healthy), role of stress, cultural values (eg, preference for larger body size), and lack of awareness about healthy lifestyles. The church was identified as a resource that could be leveraged further to positively impact health outcomes. Results demonstrate possible ways to tailor the DPP for US-based Samoan/Tongan populations by harnessing cultural traditions and addressing existing barriers and psychosocial constructs.

Transnational Corporations of Football Kin: Migration, Labor Flow, and the American Samoa MIRAB Economy

In the U.S. territory of American Samoa, gridiron football has emerged as an important driver of a stock-flow relationship in which the stock of overseas-resident migrant athletic laborers sustains the flow of remittances to their extended family in their homeland. Within this article, I consider the significance of gridiron football within American Samoa’s MIRAB ( Migration, Remittances, Aid and Bureaucracy) economy, a model of Pacific Island microeconomies characterized by migration, remittances, foreign aid, and public bureaucracy. Based on a series of personal interviews with high school football players between the ages of 15 and 18 years on the Eastern football team squad, as well as more than a dozen coaches, parents, educator, and directors associated with the production of American Samoan High School football ( n = 60), I critically examine the social, cultural, and economic determinants involved in the collective decision-making process of footballers to emigrate to the U.S. mainland. I find that family units in the American Samoa operate as, to rephrase Bertram and Watters, transnational corporations of football kin, working collectively to develop and train skilled football laborers toward the accumulation of various forms of economic and social remittances for the benefit of the individual and extended family unit. More broadly, gridiron football in American Samoa produces a stock-flow relationship whereby a stock of Samoan gridiron footballers migrates to U.S. colleges and universities to support the flow of remittances and aid that sustains the island’s MIRAB economy.

Contextualizing child-centeredness: Lessons from an American Samoan Head Start

Child-centeredness is a pedagogical approach common in US early childhood education, one that advocates young children should direct their own learning and excercise individual choice in activitites. This approach is reflected in national US Head Start policy. Using multivocal, video-cued, and traditional ethnographic methods, this study presents an analysis of interview data collected from three focus groups with American Samoan teachers to argue that the child-centered approach in newly adopted performance standards may not actually be child-centered, particuarly when ignoring the knowledge base and cultural expectations for children in culturally diverse communities. Analyzed through post-colonial theory, which recognizes the erasure of indigenous approaches to educating young children, we focus on Samoan teachers’ understanding of child-centeredness. Results indicate Samoan teachers had drastically different understandings of child-centeredness, instead pointing to optimal pedagogy as collaborative, community-oriented, and structured, and stressing the value of learning from each other. In forgrounding the voice of Samoan educators, we complicate the existing and pervasive binary positioning of child-centered and teacher-directed instruction in early childhood curriculums, to offer another alternative, an expanded notion of child-centeredness that is contextually bound and locally determined.

Pelvic Organ Prolapse Symptoms in American Samoan Women

American Samoa has one of the highest rates of obesity worldwide, making it a population at high risk for pelvic organ prolapse (POP). The primary objective of this study was to describe the presence of POP symptoms and associated degree of bother in American Samoan women. The secondary objective was to determine which characteristics are associated with POP symptoms in this cohort. We performed a cross-sectional survey of women presenting to the waiting room of the emergency department of the Lyndon B. Johnson Tropical Medical Center in Faga'alu, American Samoa from February to March 2017. Questions included self-described characteristics and the Pelvic Organ Prolapse Distress Inventory 6. Univariate distributions were described and comparisons of social and health characteristics were made between women without POP symptoms and those with at least 1 POP symptom. Two hundred eighty-four women were approached and 225 women completed the survey (79% response rate). The mean (SD) age was 40.5 (14.7), the mean (SD) body mass index was 36.4 (8.7), and the median (range) number of vaginal births was 2 (0-14). A total of 44.2% endorsed at least 1 POP symptom, most commonly pelvic pressure (29.9%) and feeling of incomplete bladder emptying (26.7%). The number of vaginal births was associated with lower abdominal pressure (P = 0.04) and hysterectomy was associated with pelvic heaviness (P = 0.05). This is the first study investigating POP in American Samoa. Almost half of women reported at least 1 pelvic floor symptom, demonstrating the need for further research on pelvic floor disorders within this high-risk population.

Zika virus in American Samoa: challenges to prevention in the context of health disparities and non-communicable disease

Background: Zika virus (ZIKV) is linked to deleterious foetal and neonate outcomes. Maternal exposure to ZIKV through mosquitoes and sexual fluids creates a public health challenge for communities and policymakers, which is exacerbated by high levels of chronic non-communicable diseases in American Samoa.Aim: This study aimed to identify structural barriers to ZIKV prevention in American Samoa and situate them within locally relevant cultural and epidemiological contexts.Subjects and methods: This study assessed knowledge, attitudes and access to ZIKV prevention among 180 adults in American Samoan public health clinics. It queried knowledge about pre-natal care, protection against mosquitoes and condom use.Results: Women were most likely to identify pre-natal care as important. The majority of participants were able to identify how to prevent mosquito bites, but may have been unable to follow through due to socioeconomic and infrastructure limitations. Few participants identified condom use as a preventative measure against ZIKV. Prevention misconceptions were most pronounced in women of low socioeconomic status.Conclusions: These findings reinforce the need for a multi-pronged approach to ZIKV. This study highlights the need for information on culturally specific barriers and recognition of additional challenges associated with dual burden in marginal populations where social inequalities exacerbate health issues.

Samholides, Swinholide-Related Metabolites from a Marine Cyanobacterium cf. Phormidium sp.

Cancer cell cytotoxicity was used to guide the isolation of nine new swinholide-related compounds, named samholides A–I (1–9), from an American Samoan marine cyanobacterium cf. Phormidium sp. Their structures were determined by extensive analysis of 1D and 2D NMR spectroscopic data. The new compounds share an unusual 20-demethyl 44-membered lactone ring composed of two monomers, and they demonstrate structural diversity arising from geometric isomerization of double bonds, sugar units with unique glyceryl moieties and varied methylation patterns. All of the new samholides were potently active against the H-460 human lung cancer cell line with IC50 values ranging from 170 to 910 nM. The isolation of these new swinholide-related compounds from a marine cyanobacterium reinvigorates questions concerning the evolution and biosynthetic origin of these natural products.

Healthcare Providers Attitudes and Knowledge Toward Dementia in American Samoan Culture (S743)

Healthcare Providers Attitudes and Knowledge Toward Dementia in American Samoan Culture (S743)

Conceptions of pregnancy health and motivations for healthful behavior change among women in American Samoa.

American Samoan women are particularly at risk of obesity-related non-communicable disease (NCD), requiring efficacious interventions to protect their health and that of their infants. Prior studies have identified pregnancy as an ideal time for behavior change interventions related to NCD. This study aimed to understand American Samoan women's conceptions of health during pregnancy, their motivations for pregnancy behavior change, and the role of their family in both enabling and preventing these changes. Eighteen women (2-19 weeks post-partum) completed semi-structured interviews that explored their experiences of pregnancy-related behavior change and social support. A thematic analysis identified prominent themes. A stages of change framework was used to describe the sample's readiness for behavior change. Participants expressed a Westernized conception of health during pregnancy that focused on eating a balanced diet and exercising regularly; behaviors that would usually be stigmatized outside of pregnancy. Many were in the contemplative/pre-contemplative stages of change, although some reported initiating healthful behaviors in pregnancy. Participants overwhelmingly described external motivations for adopting healthy behaviors, most notably the perceived benefit to their baby. During pregnancy, women reported protective treatment from their families as a result of communal ownership over the baby that is potentially limiting for women's agency over their health. This study confirmed pregnancy as an opportune moment for health behavior intervention, especially within the context of Samoan culture. Future efforts should capitalize on external motivations for behavior change but also encourage the development of internal motivators to sustain changes initiated in pregnancy post-partum.

Cinachyrella anatriaenilla sp. nov., a new tetillid sponge with microacanthoxeas from American Samoa in the South Pacific.

Several sponges from American Samoa, collected by the Coral Reef Research Foundation, Republic of Palau, were tentatively identified by one of us as Acanthotetilla cf seychellensis (Thomas 1973), due to the possession of relatively small acanthose oxeas, compared to those of other species of the genus Acanthotetilla Burton 1959. These sponges were later compared to Cinachyrella australiensis (Carter 1886), taking into account the lack of conspicuous spination on the acanthose oxeas and general features of spiculation and skeletal organisation. The specimens were later considered to represent a new species of the genus Cinachyrella Wilson 1925, after a careful comparison was made between the American Samoan specimens and C. australiensis which also contains small acanthose oxeas. Several recent molecular phylogenetic studies have confirmed the generic assignment of one of the American Samoan specimens as belonging to Cinachyrella. Cinachyrella anatriaenilla sp. nov., described herein, is the fifth of 40 Cinachyrella spp. that contain lightly spined microacanthoxeas.

Integrating Molecular Networking and Biological Assays To Target the Isolation of a Cytotoxic Cyclic Octapeptide, Samoamide A, from an American Samoan Marine Cyanobacterium

Integrating LC-MS/MS molecular networking and bioassay-guided fractionation enabled the targeted isolation of a new and bioactive cyclic octapeptide, samoamide A (1), from a sample of cf. Symploca sp. collected in American Samoa. The structure of 1 was established by detailed 1D and 2D NMR experiments, HRESIMS data, and chemical degradation/chromatographic (e.g., Marfey's analysis) studies. Pure compound 1 was shown to have in vitro cytotoxic activity against several human cancer cell lines in both traditional cell culture and zone inhibition bioassays. Although there was no particular selectivity between the cell lines tested for samoamide A, the most potent activity was observed against H460 human non-small-cell lung cancer cells (IC50 = 1.1 μM). Molecular modeling studies suggested that one possible mechanism of action for 1 is the inhibition of the enzyme dipeptidyl peptidase (CD26, DPP4) at a reported allosteric binding site, which could lead to many downstream pharmacological effects. However, this interaction was moderate when tested in vitro at up to 10 μM and only resulted in about 16% peptidase inhibition. Combining bioassay screening with the cheminformatics strategy of LC-MS/MS molecular networking as a discovery tool expedited the targeted isolation of a natural product possessing both a novel chemical structure and a desired biological activity.

Molt patterns, age criteria, and molt-breeding dynamics in American Samoan landbirds

ABSTRACT We examined 135 specimens and analyzed 1,735 captures of indigenous American Samoan landbirds, of nine target species in seven families, to document molt patterns, assess the extent of molt-breeding overlap, and present criteria to determine age. Preformative molts varied from absent to complete, and there was no confirmed evidence for prealternate molts. Molt strategies, age-determination criteria, and remigial replacement sequences were largely consistent with those of other temperate and tropical bird species within the same families. Suspended and/or arrested molts were recorded in seven species and staffelmauser or stepwise molt in two species, including the first report in a passerine. Our data suggest that staffelmauser and suspension of molt in passerines may share a common underlying mechanism. Despite broad overlap of breeding and molting seasons at the population level, we observed little evidence of molt-breeding overlap at the individual level. We suggest that molt and accompanying r...