Putative causal inference for the relationship between obesity and sex hormones in males: a bidirectional Mendelian randomization study
Background Obesity is a chronic disease with a high prevalence rate and is an established risk factor for human health. Body mass index (BMI) is a common and primary indicator used in assessing obesity. This work aims to investigate the putative causal relationship among BMI, sex hormone-binding globulin (SHBG), bioavailable testosterone (BioT), and estradiol levels. Materials and Methods We conducted a bidirectional Mendelian randomization study, using single-nucleotide polymorphisms (SNPs) strongly associated with BMI, SHBG, BioT, and estradiol as instrumental variables. All SNPs were identified from the genome-wide association study (GWAS) summary data of large sample studies recruiting more than 150,000 European adult male individuals. The inverse-variance-weighted (IVW) approach was used as a primary algorithm for putative causal estimation. Results Genetically predicted elevated BMI was associated with decreased SHBG (IVW, β = −0.103, 95% confidence interval [CI] [−0.113 to −0.092], P = 1.50 × 10−77) and BioT levels (IVW, β = −0.139, 95% CI [−0.165 to −0.113], P = 9.54 × 10−26) and high estradiol levels (IVW, β = 0.014, 95% CI [0.009–0.019], P = 2.19 × 10−7). Increased SHBG levels were causally associated with low BMI (IVW, β = −0.051, 95% CI [−0.098 to −0.005], P = 0.030) and BioT (IVW, β = −0.126, 95% CI [−0.175 to −0.077], P = 5.97 × 10−7) and high estradiol levels (IVW, β = 0.046, 95% CI [0.035–0.056], P = 6.51 × 10−17). Conversely, no evidence of an effect of estradiol imbalance on SHBG levels (IVW, β = 1.035, 95% CI [−0.854 to 2.926], P = 0.283) and BMI (IVW, β = 0.091, 95% CI [−0.094 to 0.276], P = 0.336) was obtained. However, increased BioT levels were causally associated with lower SHBG levels (IVW, β = −0.044, 95% CI [−0.061 to −0.026], P = 8.76 × 10−7), not BMI (IVW, β = −0.006, 95% CI [−0.035 to 0.023], P = 0.679). Conclusions The findings support a network putative causal relationship among BMI, SHBG, BioT, and estradiol. SHBG, BioT, and estradiol may partly mediate the effect of obesity on male health. Reasonably modulating BioT and estradiol, especially SHBG, facilitated the attenuation of the harmful effects of obesity on male health.
Wan et al. (2023) Putative causal inference for the relationship between obesity and sex hormones in males: a bidirectional Mendelian randomization study. PeerJ 11:e15760 https://doi.org/10.7717/peerj.15760
Why can people with developmental prosopagnosia recognise some familiar faces? Insights from subjective experience
Developmental prosopagnosia is a relatively common visuo-cognitive condition, characterised by impaired facial identity recognition. Impairment severity appears to reside on a continuum, however, it is unknown whether instances of milder deficits reflect the successful use of spontaneous (typical) face recognition strategies, or the application of extraneous compensatory cues to recognition. Here, we explore this issue in two studies. First, 23 adults with developmental prosopagnosia were asked about their use of spontaneous versus compensatory face recognition techniques in everyday life, using a series of closed- and open-ended questions. Second, the same participants performed a computerised famous face recognition task where they were asked to provide reasons why they could make any successful identifications. Findings from both studies suggest that people with developmental prosopagnosia can successfully, and quite frequently, use compensatory strategies to recognition, and that these cues support the majority of instances of preserved familiar face recognition. In contrast, 16 of the 23 participants were able to spontaneously recognise familiar faces on at least some occasions, but there were vast individual differences in frequencies of success. These findings have important implications for our conceptualisation of the condition, as well as for diagnostic practice.
Portch et al. (2023) Why can people with developmental prosopagnosia recognise some familiar faces? Insights from subjective experience. PeerJ 11:e15497 https://doi.org/10.7717/peerj.15497
Functional trait diversity of Cyclanthaceae and its convergent evolution with Araceae in Neotropical forests
The Cyclanthaceae comprise a relatively small family of about 230 species and 12 genera in the Pandanales that is widespread in wet Neotropical forests. The great majority of species can be divided into three growth forms (understory herbs, epiphytes, and root-climbing hemiepiphytes) that share functional traits with similar growth forms present in the Araceae, a member of the Alismatales and not closely related. Our objectives were first to characterize the diversity, functional growth forms, and ecological traits of Cyclanthaceae at the La Selva Biological Station. Specific functional leaf and canopy traits of terrestrial herbs and epiphytes are very similar and associated with ecological success in both families. We further examined the functional traits of root-climbing hemiepiphytes, a specialized growth form that links the two families but rare in other families and argue that their specialized functional traits allow them to be considered as a distinct functional growth form. A key trait in distinguishing hemiepiphytes which are rare outside of the Cyclanthaceae and Araceae is the severance of the main stem hydraulic connection to the soil early in plant development. We used field data to examine the possible evolutionary pathways of developmental and ecological transition from terrestrial to hemiepiphyte growth forms. The broader ecological success of hemiepiphytic Araceae compared to Cyclanthaceae is hypothesized to result from the presence of heteroblasty in developing stems and leaves which allows more efficient utilization of complex canopy light environments of wet tropical forests.
Riordan et al. (2023) Functional trait diversity of Cyclanthaceae and its convergent evolution with Araceae in Neotropical forests. PeerJ 11:e15557 https://doi.org/10.7717/peerj.15557
Pogonias courbina sperm characteristcs in its first reproductive season
Southern black drum (Pogonias courbina) is a species distributed along the western Atlantic Ocean, and it is the largest Sciaenidae observed in the coast of Rio Grande do Sul state, Brazil. However, it is listed as a vulnerable species at The IUCN Red List of Threatened Species™, and their fishing is prohibited. The objective of this study was to determine the sperm characteristics of P. courbina. Sperm samples of five young males (two-year-old fish) were collected through abdominal pressure. The sperm kinetics parameters were sperm motility (MOT) 10.7 ± 5.6%, curvilinear velocity (VCL) 120.07 ± 16.16 mm s ± 1, average path velocity (VAP) 75.64 ± 23.78 mm s ± 1, straight-line velocity (VSL) 62.49 ± 15.83 mm s ± 1, straightness (STR) 83.9 ± 5.3%, wobble (WOB) 61.9 ± 12.7%, beat cross frequency (BCF) 42.981 ± 4.627 Hz and progression (PRG) 1,805.4 ± 564.5 µm. The proportion of normal spermatozoa was 35.6 ± 6.1%. About the abnormalities observed, 22.7% occurred in the tail (short tail = 0.6 ± 0.5%, distally curled tail = 2.4 ± 1.6%, strongly curled tail = 1.9 ± 1.3%, broken tail = 7.9 ± 5.1%, folded tail = 5.5 ± 0.8%, loose tail = 4.4 ± 1.9%); 14.2% occurred in the head (degenerate head = 4.2 ± 1.6%, microcephaly = 1.8 ± 2.5%, loose head = 8.2 ± 2.1%) and 27.5% of the spermatozoa showed cytoplasmatic gouts (proximal gout = 20.0 ± 8.4%, distal gout = 7.5 ± 2.8%). Besides that, a correlation analysis was performed between sperm morphology and kinetics parameters, and the spermatozoa were measured for the morphometric parameters. There was a positive correlation between BCF and normal spermatozoa (r = 0.9269). A negative correlation occurred between BCF and loose head (r = −0.9047); WOB and strongly curled tail (r = −0.8911); and PROG and strongly curled tail (r = −0.9191). The morphometric measures found for the head were length of 2.50 ± 0.21 µm and width of 2.12 ± 0.22 µm, and for the tail it was length of 37.97 ± 2.01 µm. It was possible to verify that the animals have sperm characteristics that indicate reproductive aptitude, but an abnormal behavior on sperm activation and high presence of the cytoplasmic gout abnormality indicates that the animals are not fully mature in their first reproductive season. This work contributes to a better understanding of the P. courbina spermatic parameters, what can be allies to recovery this species population in nature and promote its production in fish farms.
Benato et al. (2023) Pogonias courbina sperm characteristcs in its first reproductive season. PeerJ 11:e15600 https://doi.org/10.7717/peerj.15600
Pesticide dynamics in three small agricultural creeks in Hesse, Germany
Background Due to their high biodiversity, small water bodies play an important role for freshwater ecosystems. Nonetheless, systematic pesticide monitoring in small creeks with a catchment <30 km2 is rarely conducted. Methods In this study, event-driven water samples were taken from May until November 2017 and March until July 2018 after 20 rain events at three sampling sites with catchment areas of <27 km2 in the Wetterau, a region with intensive agriculture in Southern Hesse, Germany. Additionally, enriched extracts of the native water samples from the campaign in 2018 were used for the Microtox assay to determine baseline toxicity to invertebrates over time and sum of toxic units (STU) were calculated to compare the potential toxicity of the samples. Results Overall, 37 pesticides and 17 transformation products were found, whereby the herbicide metamitron (79 µg/L) showed the highest concentration. Regularly, pesticide concentrations peaked at the time of the highest water level within each sampling event. Within each sampling event maximum pesticide concentration was mostly reached in water samples taken during the first two hours. The sum of the time-weighted mean concentration values of all pesticides was between 2.0 µg/L and 7.2 µg/L, whereby the measured concentrations exceeded their regulatory acceptable concentration (RAC) at 55% of all sampling events for at least one pesticide. The mean EC50 values varied between 28.6 ± 13.1 to 41.3 ± 12.1 REF (relative enrichment factor). The results indicated that several samples caused baseline toxicity, whereby the highest activity was measured at the time of highest water levels and pesticides concentrations, and then steadily decreased in parallel with the water level. Median STUs of invertebrates ranged from −2.10 to −3.91, of algae/aquatic plants from −0.79 to −1.84 and of fish from −2.47 to −4.24. For one of the three sampling sites, a significant linear correlation between baseline toxicity and STUinvertebratewas found (r2 = 0.48). Conclusion The results of the present study suggest that (1) current pesticide monitoring programs underestimate risks posed by the exposure to pesticides for aquatic organisms and (2) pre-authorization regulatory risk assessment schemes are insufficient to protect aquatic environments.
Environmental Contamination and Remediation
Betz-Koch et al. (2023) Pesticide dynamics in three small agricultural creeks in Hesse, Germany. PeerJ 11:e15650 https://doi.org/10.7717/peerj.15650
Basil functional and growth responses when cultivated via different aquaponic and hydroponics systems
Background Aquaponics is an innovative farming system that combines hydroponics and aquaculture, resulting in the production of both crops and fish. Decoupled aquaponics is a new approach introduced in aquaponics research for the elimination of certain system bottlenecks, specifically targeting the optimization of crops and fish production conditions. The aquaponics-related literature predominantly examines the system’s effects on crop productivity, largely overlooking the plant functional responses which underlie growth and yield performance. The aim of the study was the integrated evaluation of basil performance cultivated under coupled and decoupled aquaponic systems compared with a hydroponic one, in terms of growth and functional parameters in a pilot-scale aquaponics greenhouse. Methods We focused on the efficiency of the photosynthetic process and the state of the photosynthetic machinery, assessed by instantaneous gas exchange measurements as well as photosynthetic light response curves, and in vivo chlorophyll a fluorescence. Light use efficiency was estimated through leaf reflectance determination. Photosynthetic pigments content and leaf nutritional state assessments completed the picture of basil functional responses to the three different treatments/systems. The plant’s functional parameters were assessed at 15-day intervals. The experiment lasted for two months and included an intermediate and a final harvest during which several basil growth parameters were determined. Results Coupled aquaponics resulted in reduced growth, which was mainly ascribed to sub-sufficient leaf nutrient levels, a fact that triggered a series of negative feedbacks on all aspects of their photosynthetic performance. These plants experienced a down-regulation of PSII activity as reflected in the significant decreases of quantum yield and efficiency of electron transport, along with decreased photosynthetic pigments content. On the contrary, decoupled aquaponics favored both growth and photochemistry leading to higher light use efficiency compared with coupled system and hydroponics, yet without significant differences from the latter. Photosynthetic light curves indicated constantly higher photosynthetic capacity of the decoupled aquaponics-treated basil, while also enhanced pigment concentrations were evident. Basil functional responses to the three tested production systems provided insights on the underlying mechanisms of plant performance highlighting key-points for systems optimization. We propose decoupled aquaponics as an effective system that may replace hydroponics supporting high crops productivity. We suggest that future works should focus on the mechanisms involved in crop and fish species function, the elucidation of which would greatly contribute to the optimization of the aquaponics productivity.
Mourantian et al. (2023) Basil functional and growth responses when cultivated via different aquaponic and hydroponics systems. PeerJ 11:e15664 https://doi.org/10.7717/peerj.15664
Variation in Pheidole nodus (Hymenoptera: Formicidae) functional morphology across urban parks
Background Habitat fragmentation and consequent population isolation in urban areas can impose significant selection pressures on individuals and species confined to urban islands, such as parks. Despite many comparative studies on the diversity and structure of ant community living in urban areas, studies on ants’ responses to these highly variable ecosystems are often based on assemblage composition and interspecific mean trait values, which ignore the potential for high intraspecific functional trait variation among individuals. Methods Here, we examined differences in functional traits among populations of the generalist ant Pheidole nodus fragmented between urban parks. We used pitfall trapping, which is more random and objective than sampling colonies directly, despite a trade-off against sample size. We then tested whether trait-filtering could explain phenotypic differences among urban park ant populations, and whether ant populations in different parks exhibited different phenotypic optima, leading to positional shifts in anatomical morphospace through the regional ant meta-population. Results Intraspecific morphological differentiation was evident across this urban region. Populations had different convex hull volumes, positioned differently over the morphospace. Conclusions Fragmentation and habitat degradation reduced phenotypic diversity and, ultimately, changed the morphological optima of populations in this urban landscape. Considering ants’ broad taxonomic and functional diversity and their important role in ecosystems, further work over a variety of ant taxa is necessary to ascertain those varied morphological response pathways operating in response to population segregation in urban environments.
Luo et al. (2023) Variation in Pheidole nodus (Hymenoptera: Formicidae) functional morphology across urban parks. PeerJ 11:e15679 https://doi.org/10.7717/peerj.15679
Tea intake or consumption and the risk of dementia: a meta-analysis of prospective cohort studies
Purpose Dementia affects as many as 130 million people, which presents a significant and growing medical burden globally. This meta-analysis aims to assess whether tea intake, tea consumption can reduce the risk of dementia, Alzheimer’s disease (AD) and Vascular dementia (VD). Patients and methods Cochrane Library, PubMed and Embase were searched for cohort studies from inception to November 1, 2022. The Newcastle Ottawa Quality Assessment Scale (NOS) was applied to evaluate the risk of bias of the included studies. We extracted the data as the relative risks (RRs) for the outcome of the interest, and conducted the meta-analysis utilizing the random effect model due to the certain heterogeneity. Sensitivity analysis were performed by moving one study at a time, Subgroup-analysis was carried out according to different ages and dementia types. And the funnel plots based on Egger’s and Begger’s regression tests were used to evaluate publication bias. All statistical analyses were performed using Stata statistical software version 14.0 and R studio version 4.2.0. Results Seven prospective cohort studies covering 410,951 individuals, which were published from 2009 and 2022 were included in this meta-analysis. The methodological quality of these studies was relatively with five out of seven being of high quality and the remaining being of moderate. The pooling analysis shows that the relationship between tea intake or consumption is associated with a reduced risk of all-cause dementia (RR = 0.71, 95% CI [0.57–0.88], I2 = 79.0%, p < 0.01). Further, the subgroup-analysis revealed that tea intake or consumption is associated with a reduced risk of AD (RR = 0.88, 95% CI [0.79–0.99], I2 = 52.6%, p = 0.024) and VD (RR = 0.75, 95% CI [0.66–0.85], I = 0.00%, p < 0.001). Lastly, tea intake or consumption could reduce the risk of all-cause dementia to a greater degree among populations with less physical activity, older age, APOE carriers, and smokers. Conclusion Our meta-analysis demonstrated that tea (green tea or black tea) intake or consumption is associated with a significant reduction in the risk of dementia, AD or VD. These findings provide evidence that tea intake or consumption should be recognized as an independent protective factor against the onset of dementia, AD or VD.
Jiang et al. (2023) Tea intake or consumption and the risk of dementia: a meta-analysis of prospective cohort studies. PeerJ 11:e15688 https://doi.org/10.7717/peerj.15688
Elevated estradiol levels on hCG trigger day adversely effects on the clinical pregnancy rates of blastocyst embryo transfer but not cleavage-stage embryo transfer in fresh cycles: a retrospective cohort study
Background Elevated estradiol (E2) levels are an inevitable outcome of the controlled ovulation hyperstimulation. However, the effect of this change on pregnancy is still uncertain. Our study aimed to analyze the impact of increased serum E2 at the day of human chorionic gonadotropin (hCG) administration on the clinical outcomes of women with fresh embryo transfer (ET) cycles. Methods This study included 3,009 fresh ET cycles from October 2015 to September 2021. Based on the stage of embryos transferred, these cycles were categorized into the cleavage group and blastocyst group. Both groups were then divided into four sets according to E2 levels when hCG was administered: set 1 (E2 ≤ 2,000 pg/ml), set 2 (E2 = 2,001–3,000 pg/ml), set 3 (E2 = 3,001–4,000 pg/ml), and set 4 (E2 > 4,000 pg/ml). The primary outcome was the clinical pregnancy rate (CPR). Binary logistics regression analysis was established to explore the association between CPR and E2 levels. Specifically, the threshold effect of serum E2 on CPR was revealed using the two-piecewise linear regression analyses. Results The multivariate regression model in the cleavage group showed that patients’ CPR in set 4 was 1.59 times higher than those in reference set 1, but the statistical difference was insignificant (P = 0.294). As for the blastocyst group, patients in set 4 had a lower CPR with adjusted ORs of 0.43 (P = 0.039) compared to patients in set 1. The inflection point for the blastocyst group was 39.7 pg/dl according to the results of the two-piecewise linear regression model. When E2 levels were over the point, the CPR decreased by 17% with every 1 pg/dl increases in serum E2 (adjusted OR = 0.83, 95% CI [0.72–0.96], P = 0.012). Conclusions Elevated E2 levels (>39.7 pg/dl) on hCG trigger day were associated with decreased CPR in patients with fresh blastocyst ET. However, it had no similar effect on the CPR of patients with fresh cleavage-stage ET.
Meng et al. (2023) Elevated estradiol levels on hCG trigger day adversely effects on the clinical pregnancy rates of blastocyst embryo transfer but not cleavage-stage embryo transfer in fresh cycles: a retrospective cohort study. PeerJ 11:e15709 https://doi.org/10.7717/peerj.15709
Sex difference in the discordance between Abbott Architect and EuroImmun serological assays
Background This study evaluated the discordance between Abbott Architect SARS-CoV-2 IgG and EUROIMMUN SARS-COV-2 ELISA in a seroprevalence study. Methods From June 10 to August 15, 2020, 8,246 specimens were dually evaluated by the Abbott Architect SARS-CoV-2 IgG (Abbott) and the EUROIMMUN SARS-CoV-2 ELISA (EI) assays. Sex-stratified phi correlation coefficients were calculated to evaluate the concordance between Abbott and EI assay’s quantitative results. Multivariable mixed-effect logistic models were implemented to evaluate the association between assay positivity and sex on a low prevalence sample while controlling for age, race, ethnicity, diabetes, cardiovascular disease, hypertension, immunosuppressive therapy, and autoimmune disease. Results EI positivity among males was 2.1-fold that of females; however, no significant differences in Abbott positivity were observed between sexes. At the manufacturer-recommended threshold, the phi correlation coefficient for the Abbott and EI qualitative results among females (Φ = 0.47) was 34% greater than males (Φ = 0.35). The unadjusted and fully adjusted models yielded a strong association between sex and positive EI result for the low prevalence subgroup (unadjusted OR: 2.24, CI: 1.63, 3.11, adjusted OR: 3.40, CI: 2.15, 5.39). A similar analysis of Abbott positivity in the low prevalence subgroup did not find an association with any of the covariates examined. Significant quantitative and qualitative discordance was observed between Abbott and EI throughout the seroprevalence study. Our results suggest the presence of sex-associated specificity limitations with the EI assay. As these findings may extend to other anti-S assays utilized for SARS-CoV-2 seroprevalence investigations, further investigation is needed to evaluate the generalizability of these findings.
Hartsell et al. (2023) Sex difference in the discordance between Abbott Architect and EuroImmun serological assays. PeerJ 11:e15247 https://doi.org/10.7717/peerj.15247