The relationship between egg size and helper number in cooperative breeders: a meta-analysis across species
Background Life history theory predicts that mothers should adjust reproductive investment depending on benefits of current reproduction and costs of reduced future reproductive success. These costs and benefits may in turn depend on the breeding female’s social environment. Cooperative breeders provide an ideal system to test whether changes in maternal investment are associated with the social conditions mothers experience. As alloparental helpers assist in offspring care, larger groups might reduce reproductive costs for mothers or alternatively indicate attractive conditions for reproduction. Thus, mothers may show reduced (load-lightening) or increased (differential allocation) reproductive investment in relation to group size. A growing number of studies have investigated how cooperatively breeding mothers adjust pre-natal investment depending on group size. Our aim was to survey these studies to assess, first, whether mothers consistently reduce or increase pre-natal investment when in larger groups and, second, whether these changes relate to variation in post-natal investment. Methods We extracted data on the relationship between helper number and maternal pre-natal investment (egg size) from 12 studies on 10 species of cooperatively breeding vertebrates. We performed meta-analyses to calculate the overall estimated relationship between egg size and helper number, and to quantify variation among species. We also tested whether these relationships are stronger in species in which the addition of helpers is associated with significant changes in maternal and helper post-natal investment. Results Across studies, there is a significant negative relationship between helper number and egg size, suggesting that in most instances mothers show reduced reproductive investment in larger groups, in particular in species in which mothers also show a significant reduction in post-natal investment. However, even in this limited sample, substantial variation exists in the relationship between helper number and egg size, and the overall effect appears to be driven by a few well-studied species. Discussion Our results, albeit based on a small sample of studies and species, indicate that cooperatively breeding females tend to produce smaller eggs in larger groups. These findings on prenatal investment accord with previous studies showing similar load-lightening reductions in postnatal parental effort (leading to concealed helper effects), but do not provide empirical support for differential allocation. However, the considerable variation in effect size across studies suggests that maternal investment is mitigated by additional factors. Our findings indicate that variation in the social environment may influence life-history strategies and suggest that future studies investigating within-individual changes in maternal investment in cooperative breeders offer a fruitful avenue to study the role of adaptive plasticity.
Dixit et al. (2017) The relationship between egg size and helper number in cooperative breeders: a meta-analysis across species. PeerJ 5:e4028 https://doi.org/10.7717/peerj.4028
The impact of self-incompatibility systems on the prevention of biparental inbreeding
Inbreeding in hermaphroditic plants can occur through two different mechanisms: biparental inbreeding, when a plant mates with a related individual, or self-fertilization, when a plant mates with itself. To avoid inbreeding, many hermaphroditic plants have evolved self-incompatibility (SI) systems which prevent or limit self-fertilization. One particular SI system—homomorphic SI—can also reduce biparental inbreeding. Homomorphic SI is found in many angiosperm species, and it is often assumed that the additional benefit of reduced biparental inbreeding may be a factor in the success of this SI system. To test this assumption, we developed a spatially-explicit, individual-based simulation of plant populations that displayed three different types of homomorphic SI. We measured the total level of inbreeding avoidance by comparing each population to a self-compatible population (NSI), and we measured biparental inbreeding avoidance by comparing to a population of self-incompatible plants that were free to mate with any other individual (PSI). Because biparental inbreeding is more common when offspring dispersal is limited, we examined the levels of biparental inbreeding over a range of dispersal distances. We also tested whether the introduction of inbreeding depression affected the level of biparental inbreeding avoidance. We found that there was a statistically significant decrease in autozygosity in each of the homomorphic SI populations compared to the PSI population and, as expected, this was more pronounced when seed and pollen dispersal was limited. However, levels of homozygosity and inbreeding depression were not reduced. At low dispersal, homomorphic SI populations also suffered reduced female fecundity and had smaller census population sizes. Overall, our simulations showed that the homomorphic SI systems had little impact on the amount of biparental inbreeding in the population especially when compared to the overall reduction in inbreeding compared to the NSI population. With further study, this observation may have important consequences for research into the origin and evolution of homomorphic self-incompatibility systems.
Furstenau et al. (2017) The impact of self-incompatibility systems on the prevention of biparental inbreeding. PeerJ 5:e4085 https://doi.org/10.7717/peerj.4085
Characteristics and risk factors of rheumatoid arthritis in the United States: an NHANES analysis
Background We examined the United States National Health and Nutrition Examination Survey (NHANES) database to determine factors associated with rheumatoid arthritis (RA) in adults 20 to 55 years of age. Methods NHANES data collected between 2007 and 2014, excluding the 2011–2012 period, were used. Subjects were divided into those with and without RA. Demographic, clinical, and lifestyle factors were compared between the groups. Results After applying inclusion/exclusion criteria, 8,789 persons were included in the study (8,483 without RA, 306 with RA). Multivariable analysis indicated that advanced age (odds ratio [OR] = 1.09, 95% CI [1.07–1.11], P < 0.001), regular smoking (OR = 2.19, 95% CI [1.49–3.21], P < 0.001), diabetes (OR = 2.00, 95% CI [1.35–2.95], P = 0.001), obesity (reference, normal or underweight; OR = 3.31, 95% CI [2.05–5.36], P < 0.001), and osteoporosis (OR = 3.68, 95% CI [1.64–8.22], P = 0.002) were positively associated with RA. Covered by health insurance (OR = 1.81, 95% CI [1.12–2.93], P = 0.016) and living in poverty (OR = 2.96, 95% CI [1.88–4.65], P < 0.001) were also associated with having RA. Mexican American, Hispanic white or other Hispanic ethnicity (reference, non-Hispanic white; OR = 0.54, 95% CI [0.31–0.96], P = 0.036), appropriate sleep duration (about 6–11 h, OR = 0.46, 95% CI [0.32–0.65], P < 0.001), and insufficient vitamin A intake (reference, recommended; OR = 0.70, 95% CI [0.50–0.98], P = 0.036) were negatively associated with RA. Discussion Some factors associated with RA are potentially modifiable.
Xu et al. (2017) Characteristics and risk factors of rheumatoid arthritis in the United States: an NHANES analysis. PeerJ 5:e4035 https://doi.org/10.7717/peerj.4035
Forelimb muscle and joint actions in Archosauria: insights from Crocodylus johnstoni (Pseudosuchia) and Mussaurus patagonicus (Sauropodomorpha)
Many of the major locomotor transitions during the evolution of Archosauria, the lineage including crocodiles and birds as well as extinct Dinosauria, were shifts from quadrupedalism to bipedalism (and vice versa). Those occurred within a continuum between more sprawling and erect modes of locomotion and involved drastic changes of limb anatomy and function in several lineages, including sauropodomorph dinosaurs. We present biomechanical computer models of two locomotor extremes within Archosauria in an analysis of joint ranges of motion and the moment arms of the major forelimb muscles in order to quantify biomechanical differences between more sprawling, pseudosuchian (represented the crocodile Crocodylus johnstoni) and more erect, dinosaurian (represented by the sauropodomorph Mussaurus patagonicus) modes of forelimb function. We compare these two locomotor extremes in terms of the reconstructed musculoskeletal anatomy, ranges of motion of the forelimb joints and the moment arm patterns of muscles across those ranges of joint motion. We reconstructed the three-dimensional paths of 30 muscles acting around the shoulder, elbow and wrist joints. We explicitly evaluate how forelimb joint mobility and muscle actions may have changed with postural and anatomical alterations from basal archosaurs to early sauropodomorphs. We thus evaluate in which ways forelimb posture was correlated with muscle leverage, and how such differences fit into a broader evolutionary context (i.e. transition from sprawling quadrupedalism to erect bipedalism and then shifting to graviportal quadrupedalism). Our analysis reveals major differences of muscle actions between the more sprawling and erect models at the shoulder joint. These differences are related not only to the articular surfaces but also to the orientation of the scapula, in which extension/flexion movements in Crocodylus (e.g. protraction of the humerus) correspond to elevation/depression in Mussaurus. Muscle action is highly influenced by limb posture, more so than morphology. Habitual quadrupedalism in Mussaurus is not supported by our analysis of joint range of motion, which indicates that glenohumeral protraction was severely restricted. Additionally, some active pronation of the manus may have been possible in Mussaurus, allowing semi-pronation by a rearranging of the whole antebrachium (not the radius against the ulna, as previously thought) via long-axis rotation at the elbow joint. However, the muscles acting around this joint to actively pronate it may have been too weak to drive or maintain such orientations as opposed to a neutral position in between pronation and supination. Regardless, the origin of quadrupedalism in Sauropoda is not only linked to manus pronation but also to multiple shifts of forelimb morphology, allowing greater flexion movements of the glenohumeral joint and a more columnar forelimb posture.
Otero et al. (2017) Forelimb muscle and joint actions in Archosauria: insights from Crocodylus johnstoni (Pseudosuchia) and Mussaurus patagonicus (Sauropodomorpha). PeerJ 5:e3976 https://doi.org/10.7717/peerj.3976
Do rotational shear-cushioning shoes influence horizontal ground reaction forces and perceived comfort during basketball cutting maneuvers?
Background Court shoe designs predominantly focus on reducing excessive vertical ground reaction force, but shear force cushioning has received little attention in the basketball population. We aimed to examine the effect of a novel shoe-cushioning design on both resultant horizontal ground reaction forces and comfort perception during two basketball-specific cutting movements. Methods Fifteen university team basketball players performed lateral shuffling and 45-degree sidestep cutting at maximum effort in basketball shoes with and without the shear-cushioning system (SCS). Paired t-tests were used to examine the differences in kinetics and comfort perception between two shoes. Results SCS shoe allowed for larger rotational material deformation compared with control shoes, but no significant shoe differences were found in braking phase kinetics during both cutting movements (P = 0.35). Interestingly, a greater horizontal propulsion impulse was found with the SCS during 45-degree cutting (P < 0.05), when compared with the control. In addition, players wearing SCS shoes perceived better forefoot comfort (P = 0.012). During lateral shuffling, there were no significant differences in horizontal GRF and comfort perception between shoe conditions (P > 0.05). Discussion The application of a rotational shear-cushioning structure allowed for better forefoot comfort and enhanced propulsion performance in cutting, but did not influence the shear impact. Understanding horizontal ground reaction force information may be useful in designing footwear to prevent shear-related injuries in sport populations.
Lam et al. (2017) Do rotational shear-cushioning shoes influence horizontal ground reaction forces and perceived comfort during basketball cutting maneuvers?. PeerJ 5:e4086 https://doi.org/10.7717/peerj.4086
Associations of IGF2 and DRD2 polymorphisms with laying traits in Muscovy duck
Insulin-like growth factor 2 (IGF2) and dopamine receptor 2 (DRD2) play important roles in ovarian follicular development. In this study, we analyzed tissue-specific expression of the Muscovy duck IGF2 and DRD2 genes and cloned those genes transcripts. Polymorphisms in these genes were tightly linked with egg production traits and both genes were highly expressed in the ovary. Moreover, we identified five single nucleotide polymorphisms (SNPs) for IGF1 and 28 for DRD2. Mutations A-1864G and C-1704G of IGF2 were positively correlated with increased egg laying at 59 weeks (E59W) (P < 0.05). The C+7T and C+364G mutations of DRD2 were highly and significantly associated with first-egg age (FEA) and egg numbers at 300 days (E300D) (P < 0.01). Moreover, C+3301G and C+3545G of DRD2 were highly significantly associated with FEA, E59W and E300D (P < 0.01). Other mutations were positively associated with FEA or E300D or E59W (P < 0.05). These data suggest specific roles for IGF1 and DRD2 polymorphisms in egg production in Muscovy ducks.
Ye et al. (2017) Associations of IGF2 and DRD2 polymorphisms with laying traits in Muscovy duck. PeerJ 5:e4083 https://doi.org/10.7717/peerj.4083
An update on anticancer drug development and delivery targeting carbonic anhydrase IX
The expression of carbonic anhydrase (CA) IX is up-regulated in many types of solid tumors in humans under hypoxic and acidic microenvironment. Inhibition of CA IX enzymatic activity with selective inhibitors, antibodies or labeled probes has been shown to reverse the acidic environment of solid tumors and reduce the tumor growth establishing the significant role of CA IX in tumorigenesis. Thus, the development of potent antitumor drugs targeting CA IX with minimal toxic effects is important for the target-specific tumor therapy. Recently, several promising antitumor agents against CA IX have been developed to treat certain types of cancers in combination with radiation and chemotherapy. Here we review the inhibition of CA IX by small molecule compounds and monoclonal antibodies. The methods of enzymatic assays, biophysical methods, animal models including zebrafish and Xenopus oocytes, and techniques of diagnostic imaging to detect hypoxic tumors using CA IX-targeted conjugates are discussed with the aim to overview the recent progress related to novel therapeutic agents that target CA IX in hypoxic tumors.
Kazokaitė et al. (2017) An update on anticancer drug development and delivery targeting carbonic anhydrase IX. PeerJ 5:e4068 https://doi.org/10.7717/peerj.4068
Antibodies to Bordetella pertussis antigens in maternal and cord blood pairs: a Thai cohort study
Background Pertussis is a vaccine-preventable disease, yet an increasing incidence of pertussis occurs in many countries. Thailand has a long-standing pertussis vaccination policy, therefore most expectant mothers today had received vaccines as children. The resurgence of pertussis among Thai infants in recent years led us to examine the pre-existing antibodies to Bordetella pertussis antigens in a cohort of 90 pregnant women. Methods We evaluated the IgG to the Pertussis toxin (PT), filamentous hemagglutinin (FHA) and pertactin (PRN) in maternal and cord blood sera using commercial enzyme-linked immunosorbent assays (ELISA). Results When values of >10 IU/ml were accepted as potential protective concentrations, we found that the percentages of unprotected infants were 73.3%, 43.3% and 75.5% for anti-PT, anti-FHA and anti-PRN IgG, respectively. Discussion These results may explain the susceptibility for pertussis among newborn infants in Thailand and support the requirement for a pertussis booster vaccine during pregnancy, which may contribute to the passive seroprotection among newborns during the first months of life.
Wanlapakorn et al. (2017) Antibodies to Bordetella pertussis antigens in maternal and cord blood pairs: a Thai cohort study. PeerJ 5:e4043 https://doi.org/10.7717/peerj.4043
Morphological and molecular data confirm the transfer of homostylous species in the typically distylous genus Galianthe (Rubiaceae), and the description of the new species Galianthe vasquezii from Peru and Colombia
Galianthe (Rubiaceae) is a neotropical genus comprising 50 species divided into two subgenera, Galianthe subgen. Galianthe, with 39 species and Galianthe subgen. Ebelia, with 11 species. The diagnostic features of the genus are: usually erect habit with xylopodium, distylous flowers arranged in lax thyrsoid inflorescences, bifid stigmas, 2-carpellate and longitudinally dehiscent fruits, with dehiscent valves or indehiscent mericarps, plump seeds or complanate with a wing-like strophiole, and pollen with double reticulum, rarely with a simple reticulum. This study focused on two species that were originally described under Diodia due to the occurrence of fruits indehiscent mericarps: Diodia palustris and D. spicata. In the present study, classical taxonomy is combined with molecular analyses. As a result, we propose that both Diodia species belong to Galianthe subgen. Ebelia. The molecular position within Galianthe, based on ITS and ETS sequences, has been supported by the following morphological characters: thyrsoid, spiciform or cymoidal inflorescences, bifid stigmas, pollen grains with a double reticulum, and indehiscent mericarps. However, both species, unlike the remainder of the genus Galianthe, have homostylous flowers, so the presence of this type of flower significantly modifies the generic concept. In this framework, a third homostylous species, Galianthe vasquezii, from the Andean region is also described. Until now, this species remained cryptic under specimens of Galianthe palustris It differs however from the latter by having longer calyx lobes, the presence of dispersed trichomes inside the corolla lobes (vs. glabrous), fruits that are acropetally dehiscent (vs. basipetally dehiscent), and its Andean geographical distribution (vs. Paranaense). Additionally, a lectotype has been chosen for Diodia palustris, Borreria pterophora has been placed under synonymy of Galianthe palustris, and Galianthe boliviana is reported for the first time from Peru. A key of all Galianthe species with indehiscent mericarps is also provided.
Florentín et al. (2017) Morphological and molecular data confirm the transfer of homostylous species in the typically distylous genus Galianthe (Rubiaceae), and the description of the new species Galianthe vasquezii from Peru and Colombia. PeerJ 5:e4012 https://doi.org/10.7717/peerj.4012
Modus operandi and affect in Sweden: the Swedish version of the Regulatory Mode Questionnaire
Background The Regulatory Mode Questionnaire (RMQ) is the most used and internationally well-known instrument for the measurement of individual differences in the two self-regulatory modes: locomotion (i.e., the aspect of self-regulation that is concerned with movement from state to state) and assessment (i.e., the comparative aspect of self-regulation). The aim of the present study was to verify the independence of the two regulatory modes, as postulated by the Regulatory Mode Theory (Kruglanski et al., 2000), and the psychometric properties of the RMQ in the Swedish context. Furthermore, we investigated the relationship between regulatory modes (locomotion and assessment) and affective well-being (i.e., positive affect and negative affect). Method A total of 655 university and high school students in the West of Sweden (males = 408 females = 242, and five participants who didn’t report their gender; agemean = 21.93 ± 6.51) responded to the RMQ and the Positive Affect Negative Affect Schedule. We conducted two confirmatory factor analyses using structural equation modeling (SEM). A third SEM was conducted to test the relationship between locomotion and assessment to positive affect and negative affect. Results The first analyses confirmed the unidimensional factor structure of locomotion and assessment and both scales showed good reliability. The assessment scale, however, was modified by dropping item 10 (“I don’t spend much time thinking about ways others could improve themselves”.) because it showed low loading (.07, p = .115). Furthermore, the effect of locomotion on positive affect was stronger than the effect of assessment on positive affect (Z = −15.16, p < .001), while the effect of assessment on negative affect was stronger than the effect of locomotion on negative affect (Z = 10.73, p < .001). Conclusion The factor structure of the Swedish version of the RMQ is, as Regulatory Mode Theory suggests, unidimensional and it showed good reliability. The scales discriminated between the two affective well-being dimensions. We suggest that the Swedish version of the RMQ, with only minor modifications, is a useful instrument to tap individual differences in locomotion and assessment. Hence, the present study contributes to the validation of the RMQ in the Swedish culture and adds support to the theoretical framework of self-regulatory mode.
Amato et al. (2017) Modus operandi and affect in Sweden: the Swedish version of the Regulatory Mode Questionnaire. PeerJ 5:e4092 https://doi.org/10.7717/peerj.4092