Occurrence of an Intersexual Blacktip Shark in the Northern Gulf of Mexico, with Notes on the Standardization of Classifications for This Condition in Elasmobranchs

An intersexual Blacktip Shark Carcharhinus limbatus with a testis, immature female reproductive tracts (embedded), and claspers was caught in the Gulf of Mexico. Histology of the single gonad revealed that all stages of spermatogenesis were occurring; however, the absence of ovaries and a male duct system suggests that neither sex would have been functional in this individual. Intersexuality has been reported in 17 families and 36 species of elasmobranchs. The degree to which the different sexes are present in a given individual is often difficult to categorize by normal hermaphroditic standards, as this is typically an anomalous presentation in elasmobranchs. Therefore, this report provides three categories for classification (basic, incomplete, and complete intersexuality) to standardize terminology and allow for more precise comparisons to be made among elasmobranch examples. Basic intersexuals have gonadal tissue of only one sex and a combination of other male and female characters with neither or only one sex being complete. Incomplete intersexuals have gonadal tissue of both sexes and a combination of other male and female characters; however, neither or only one sex is complete. Complete intersexuals have claspers as well as gonadal tissue and tracts for both sexes. The majority of the reported intersexual elasmobranchs, including the shark described here, are basic intersexuals

A review of the ecology, palaeontology and distribution of atlantid heteropods (Caenogastropoda: Pterotracheoidea: Atlantidae)

Fewer than 1% of marine gastropod species live a holoplanktic life. Of these, the shelled heteropods of the family Atlantidae are among the most poorly understood. The atlantids potentially make up an important part of the ocean zooplankton, composing up to 69% of shelled holoplanktic gastropods in the Late Pleistocene to Recent fossil record. They are also likely to be at high risk from current and future global changes, including anthropogenic ocean acidification. However, due to their small size (<12 mm), difficulty of sampling and complicated morphology, we still lack key information about atlantid taxonomy and ecology. This makes it difficult to understand how important they are in the ocean foodweb and how they will be affected by environmental change. Although many studies have been carried out on the atlantids, these have generally been broad and unconnected. Here, we draw together this previous research, summarizing what is currently known about atlantid taxonomy, palaeontology, ecology and biogeography, and aiming to provide a foundation for future research on this group. The data indicate complex behaviours involving seasonal and vertical migration, and demonstrate extended geographical ranges, with implications for understanding the role of atlantids in the ocean foodweb and their sensitivity to environmental changes. This review highlights the urgent need for further taxonomic research on the atlantids, including molecular analysis, and for improved sampling techniques

Increased maternal TSH and decreased maternal FT4 are associated with a higher operative delivery rate in low-risk pregnancies: A prospective cohort study

Background:  The increasing number of operative deliveries is a topic of major concern in modern obstetrics. Maternal thyroid function is of known influence on many obstetric parameters. Our objective was to investigate a possible relation between maternal thyroid function, and operative deliveries. Secondary aim was to explore whether thyroid function was related to specific reasons for operative deliveries. Methods:  In this prospective cohort study, low-risk Caucasian women, pregnant of a single cephalic fetus were included. Women with known auto-immune disease, a pre-labour Caesarean section, induction of labour, breech presentation or preterm delivery were excluded. In all trimesters of pregnancy the thyroid function was assessed. Differences in mean TSH and FT4 were assessed using t-test. Mean TSH and FT4 levels for operative deliveries were determined by one way ANOVA. Repeated measurement analyses were performed (ANOVA), adjusting for BMI, partiy, maternal age and gestational age at delivery. Results:  In total 872 women were included, of which 699 (80.2 %) had a spontaneous delivery. At 36 weeks gestation women who had an operative delivery had a significantly higher mean TSH (1.63mIU/L versus 1.46mIU/L, p = 0.025) and lower mean FT4 (12.9pmol/L versus 13.3pmol/L, p = 0.007)) compared to women who had a spontaneous delivery. Mean TSH was significantly higher (p = 0.026) and mean FT4 significantly lower (p = 0.030) throughout pregnancy for women with an operative delivery due to failure to progress in second stage of labour, compared to women with a spontaneous delivery or operative delivery for other reasons. Conclusion:  Increased TSH and decreased FT4 seem to be associated with more operative vaginal deliveries and Caesarean sections. After adjusting for several confounders the association remained for operative deliveries due to failure to progress in second stage of labour, possibly to be explained by less efficient uterine action

Cation extraction by 18-crown-6 to a room-temperature ionic liquid: The effect of solvent humidity investigated by molecular dynamics simulations

We report a molecular dynamics study of the solvation of 18-crown-6 (“18C6”) and of its K+, Cs+ and Sr2+ complexes in a room-temperature ionic liquid (IL) based on 1-butyl-3-methyl-imidazolium+, PF6−. “Dry” [BMI][PF6] versus “humid” [BMI][PF6][H2O] models of the IL are compared, demonstrating the importance of solvent humidity on the solvation properties. Upon “dissolution” of a piece of crystal, 18C6 is found to undergo a conformational change from Ci to D3d, mainly due to enhanced interactions with the BMI+ solvent cations and H2O molecules, when present. The complexes were first studied with dissociated counterions. In the dry IL, the complexed K+ and Sr2+ cations are locked at the center of the crown by 1 + 1 (K+), 1 + 2 or 1 + 3 (Sr2+) PF6− anions in facial positions, respectively. The Cs+ cation is perched over the crown, solvated by 3 PF6− anions. In the humid IL, the complexed K+ also binds to 1 + 1 PF6− facial anions only (no water), whereas Sr2+ is asymmetrically coordinated to at least 3 H2O molecules. When co-complexed with Cl− or NO3− counterions, Sr2+ is shielded from the dry IL, but coordinates up to 3 additional H2O molecules in the humid IL, while K+ is not hydrated. The solvation of the “naked” K+, Cs+ and Sr2+ ions also markedly depends on the solvent humidity. K+ is coordinated to 4 PF6− anions in the dry IL and by 2 PF6− plus 3–5 H2O in the humid IL. The most spectacular difference concerns Sr2+, whose first shell is purely anionic (5 PF6−) in the dry IL, but all neutral (8 H2O) in the humid IL. According to an energy component analysis, the 18C6 crown, the cations and their complexes are better solvated by the humid than by the dry IL. Finally, we report simulations of 18C6 and on its Sr ⊂ 18C6(NO3)2 complex at the aqueous interface with the ionic liquid, showing enhanced solvent mixing, compared to the interface with classical organic liquids. The microscopic views obtained by these simulations show the active role of the ionic and aqueous components of the liquid on the solvation of the free crown, the free cations and their complexes

Lifespan cerebral grey matter changes in the marmoset monkey

International audienceLifespan cerebral grey matter changes in the marmoset monkeyF. Rémy, N. Vayssière, F. Bazzi, D. Mateo, A. Sadoun, P. Girard, M. Mescam, C. FontaIn the research field of nervous system aging, the common marmoset monkey Callithrix Jacchus may reveal a model of great interest. With its short lifespan (10 years on average), a life-long assessment of cerebral changes in an individual is made feasible in laboratory settings. Moreover, similar to humans, cognitive deficits spontaneously occur at old age and are highly variable between individuals (Sadoun et al 2019, Neurobiology of Aging 74:1-14). Here, we aimed at characterizing marmoset brain structural aging in a cross-sectional MRI study performed on 48 individuals of all ages (6 months to 14 years old, with 21 individuals above 8 years). High-resolution (0.35 × 0.35 × 0.35 mm3) T1-weighted anatomical scans were acquired on a 3T MRI system using a human wrist coil. Scans were processed in SPM12 using the voxel-based morphometry (VBM) pipeline. All images were co-registered to a home-made T1 template (average of 12 individual scans). The image segmentation used Tissue Probability Maps (TPMs) of grey matter (GM), white matter (WM), cerebrospinal fluid (CSF) and head/background, which were derived from the creation of a study-specific template using the SPM12 DARTEL procedure. GM images were then spatially normalized to the DARTEL template and smoothed. VBM of grey matter evidenced linear age-related decreases mainly in the prefrontal cortex, anterior cingulate region and hippocampus, in both hemispheres (figure). This is in line with age-related cortical changes observed in humans. Further analyses, using cortical regions-of-interest derived from the marmoset digital atlas developed in our group (Risser et al 2019, Brain Struct Funct 224(5):1957-1969) are currently underway and could be linked to behavioral performances of these animals in various tasks