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1. Human milk immune factors, maternal nutritional status, and infant sex: The INSPIRE study

   https://doi.org/10.1002/ajhb.23943  

   Caffé, Beatrice ; Blackwell, Aaron ; Fehrenkamp, Bethaney D. ; Williams, Janet E. ; Pace, Ryan M. ; Lackey, Kimberly A. ; Ruiz, Lorena ; Rodríguez, Juan M. ; McGuire, Mark A. ; Foster, James A. ; et al ( June 2023 , American Journal of Human Biology)

   Breastfeeding is an energetically costly and intense form of human parental investment, providing sole‐source nutrition in early infancy and bioactive components, including immune factors. Given the energetic cost of lactation, milk factors may be subject to tradeoffs, and variation in concentrations have been explored utilizing the Trivers‐Willard hypothesis. As human milk immune factors are critical to developing immune system and protect infants against pathogens, we tested whether concentrations of milk immune factors (IgA, IgM, IgG, EGF, TGFβ2, and IL‐10) vary in response to infant sex and maternal condition (proxied by maternal diet diversity [DD] and body mass index [BMI]) as posited in the Trivers‐Willard hypothesis and consider the application of the hypothesis to milk composition.

   We analyzed concentrations of immune factors in 358 milk samples collected from women residing in 10 international sites using linear mixed‐effects models to test for an interaction between maternal condition, including population as a random effect and infant age and maternal age as fixed effects.

   IgG concentrations were significantly lower in milk produced by women consuming diets with low diversity with male infants than those with female infants. No other significant associations were identified.

   IgG concentrations were related to infant sex and maternal diet diversity, providing minimal support for the hypothesis. Given the lack of associations across other select immune factors, results suggest that the Trivers‐Willard hypothesis may not be broadly applied to human milk immune factors as a measure of maternal investment, which are likely buffered against perturbations in maternal condition.

    

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2. Geographic variation in sexual communication in the cotton bollworm, Helicoverpa armigera

   https://doi.org/10.1002/ps.5893  

   Gao, Ke ; Torres‐Vila, Luis M. ; Zalucki, Myron P. ; Li, Yiping ; Griepink, Frans ; Heckel, David G. ; Groot, Astrid T. ( June 2020 , Pest Management Science)

   Geographic variation in male response to sex pheromone lures has been studied in the field in a number of moth species. However, only a few studies have investigated geographic variation in female calling and sex pheromone under field conditions. For an effective field implementation of sex pheromone lures, it is essential to know the local sex pheromone blend and local timing of sexual communication. We investigated the level and extent of geographic variation in the sexual communication of the important agricultural pestHelicoverpa armigera(Lepidoptera, Noctuidae) in three continents.

   We found there is no genetic variation in the calling behavior ofH. armigera. In the female sex pheromone, we found more between‐population variation than within‐population variation. In male response experiments, we found geographic variation as well. Strikingly, when adding the antagonistic compound Z11‐16:OAc to the pheromone blend ofH. armigera, significantly fewer males were caught in Australia and China, but not in Spain. This variation is likely not only due to local environmental conditions, such as photoperiod and temperature, but also to the presence of other closely related species with which communication interference may occur.

   Finding geographic variation in both the female sexual signal and the male response in this pest calls for region‐specific pheromone lures. Our study shows that the analysis of geographic variation in moth female sex pheromones as well as male responses is important for effectively monitoring pest species that occur around the globe. © 2020 The Authors.Pest Management Sciencepublished by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

    

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3. Sex‐Specific Differences in Life Span Brain Volumes in Multiple Sclerosis

   https://doi.org/10.1111/jon.12709  

   Jakimovski, Dejan ; Zivadinov, Robert ; Bergsland, Niels ; Ramasamy, Deepa P. ; Hagemeier, Jesper ; Weinstock‐Guttman, Bianca ; Kolb, Channa ; Hojnacki, David ; Dwyer, Michael G. ( May 2020 , Journal of Neuroimaging)

   Numerous sex‐specific differences in multiple sclerosis (MS) susceptibility, disease manifestation, disability progression, inflammation, and neurodegeneration have been previously reported. Previous magnetic resonance imaging (MRI) studies have shown structural differences between female and male MS brain volumes. To determine sex‐specific global and tissue‐specific brain volume throughout the MS life span in a real‐world large MRI database.

   A total of 2,199 MS patients (female/male ratio of 1,651/548) underwent structural MRI imaging on either a 1.5‐T or 3‐T scanner. Global and tissue‐specific volumes of whole brain (WBV), white matter, and gray matter (GMV) were determined by utilizing Structural Image Evaluation using Normalisation of Atrophy Cross‐sectional (SIENAX). Lateral ventricular volume (LVV) was determined with the Neurological Software Tool for REliable Atrophy Measurement (NeuroSTREAM). General linear models investigated sex and age interactions, and post hoc comparative sex analyses were performed.

   Despite being age‐matched with female MS patents, a greater proportion of male MS patients were diagnosed with progressive MS and had lower normalized WBV (P < .001), GMV (P< .001), and greater LVV (P< .001). In addition to significant stand‐alone main effects, an interaction between sex and age had an additional effect on the LVV (F‐statistics = 4.53,P= .033) and GMV (F‐statistics = 4.59,P= .032). The sex and age interaction was retained in both models of LVV (F‐statistics = 3.31,P= .069) and GMV (F‐statistics = 6.1,P= .003) when disease subtype and disease‐modifying treatment (DMT) were also included. Although male MS patients presented with significantly greater LVV and lower GMV during the early and midlife period when compared to their female counterparts (P< .001 for LVV andP< .019 for GMV), these differences were nullified in 60+ years old patients. Similar findings were seen within a subanalysis of MS patients that were not on any DMT at the time of enrollment.

   There are sex‐specific differences in the LVV and GMV over the MS life span.

    

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4. Zebrafish gonad mutant models reveal neuroendocrine mechanisms of brain sexual dimorphism and male mating behaviors of different brain regions

   https://doi.org/10.1186/s13293-023-00534-7  

   Dai, Xiangyan ; Pradhan, Ajay ; Liu, Jiao ; Liu, Ruolan ; Zhai, Gang ; Zhou, Linyan ; Dai, Jiyan ; Shao, Feng ; Yuan, Zhiyong ; Wang, Zhijian ; et al ( August 2023 , Biology of Sex Differences)

   Sexually dimorphic mating behaviors differ between sexes and involve gonadal hormones and possibly sexually dimorphic gene expression in the brain. However, the associations among the brain, gonad, and sexual behavior in teleosts are still unclear. Here, we utilized germ cells-freetdrd12knockout (KO) zebrafish, and steroid synthesis enzymecyp17a1-deficient zebrafish to investigate the differences and interplays in the brain–gonad–behavior axis, and the molecular control of brain dimorphism and male mating behaviors.

   Tdrd12^+/−;cyp17a1^+/−double heterozygous parents were crossed to obtaintdrd12^−/−;cyp17a1^+/+(tdrd12 KO),tdrd12^+/+;cyp17a1^−/−(cyp17a1 KO), andtdrd12^−/−;cyp17a1^−/−(double KO) homozygous progenies. Comparative analysis of mating behaviors were evaluated using Viewpoint zebrafish tracking software and sexual traits were thoroughly characterized based on anatomical and histological experiments in these KOs and wild types. The steroid hormone levels (testosterone, 11-ketotestosterone and 17β-estradiol) in the brains, gonads, and serum were measured using ELISA kits. To achieve a higher resolution view of the differences in region-specific expression patterns of the brain, the brains of these KOs, and control male and female fish were dissected into three regions: the forebrain, midbrain, and hindbrain for transcriptomic analysis.

   Qualitative analysis of mating behaviors demonstrated thattdrd12^−/−fish behaved in the same manner as wild-type males to trigger oviposition behavior, whilecyp17a1^−/−and double knockout (KO) fish did not exhibit these behaviors. Based on the observation of sex characteristics, mating behaviors and hormone levels in these mutants, we found that the maintenance of secondary sex characteristics and male mating behavior did not depend on the presence of germ cells; rather, they depended mainly on the 11-ketotestosterone and testosterone levels secreted into the brain–gonad regulatory axis. RNA-seq analysis of different brain regions revealed that the brain transcript profile oftdrd12^−/−fish was similar to that of wild-type males, especially in the forebrain and midbrain. However, the brain transcript profiles ofcyp17a1^−/−and double KO fish were distinct from those of wild-type males and were partially biased towards the expression pattern of the female brain. Our results revealed important candidate genes and signaling pathways, such as synaptic signaling/neurotransmission, MAPK signaling, and steroid hormone pathways, that shape brain dimorphism and modulate male mating behavior in zebrafish.

   Our results provide comprehensive analyses and new insights regarding the endogenous interactions in the brain–gonad–behavior axis. Moreover, this study revealed the crucial candidate genes and neural signaling pathways of different brain regions that are involved in modulating brain dimorphism and male mating behavior in zebrafish, which would significantly light up the understanding the neuroendocrine and molecular mechanisms modulating brain dimorphism and male mating behavior in zebrafish and other teleost fish.

    

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5. Differences in the thermal physiology of adult Yarrow's spiny lizards ( Sceloporus jarrovii ) in relation to sex and body size

   https://doi.org/10.1002/ece3.1297  

   Beal, Martin S. ; Lattanzio, Matthew S. ; Miles, Donald B. ( October 2014 , Ecology and Evolution)

   Sexual size dimorphism (SSD) is often assumed to reflect the phenotypic consequences of differential selection operating on each sex. Species that exhibit SSD may also show intersexual differences in other traits, including field‐active body temperatures, preferred temperatures, and locomotor performance. For these traits, differences may be correlated with differences in body size or reflect sex‐specific trait optima. Male and female Yarrow's spiny lizards,Sceloporus jarrovii, in a population in southeastern Arizona exhibit a difference in body temperature that is unrelated to variation in body size. The observed sexual variation in body temperature may reflect divergence in thermal physiology between the sexes. To test this hypothesis, we measured the preferred body temperatures of male and female lizards when recently fed and fasted. We also estimated the thermal sensitivity of stamina at seven body temperatures. Variation in these traits provided an opportunity to determine whether body size or sex‐specific variation unrelated to size shaped their thermal physiology. Female lizards, but not males, preferred a lower body temperature when fasted, and this pattern was unrelated to body size. Larger individuals exhibited greater stamina, but we detected no significant effect of sex on the shape or height of the thermal performance curves. The thermal preference of males and females in a thermal gradient exceeded the optimal temperature for performance in both sexes. Our findings suggest that differences in thermal physiology are both sex‐ and size‐based and that peak performance at low body temperatures may be adaptive given the reproductive cycles of this viviparous species. We consider the implications of our findings for the persistence ofS. jarroviiand other montane ectotherms in the face of climate warming.

    

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