Interferon priming is essential for human CD34+ cell-derived plasmacytoid dendritic cell maturation and function.

Plasmacytoid dendritic cells (pDC) are essential for immune competence. Here we show that pDC precursor differentiated from human CD34+ hematopoietic stem and progenitor cells (HSPC) has low surface expression of pDC markers, and has limited induction of type I interferon (IFN) and IL-6 upon TLR7 and TLR9 agonists treatment; by contrast, cGAS or RIG-I agonists-mediated activation is not altered. Importantly, after priming with type I and II IFN, these precursor pDCs attain a phenotype and functional activity similar to that of peripheral blood-derived pDCs. Data from CRISPR/Cas9-mediated genome editing of HSPCs further show that HSPC-pDCs with genetic modifications can be obtained, and that expression of the IFN-α receptor is essential for the optimal function, but dispensable for the differentiation, of HSPC-pDC percursor. Our results thus demonstrate the biological effects of IFNs for regulating pDC function, and provide the means of generating of gene-modified human pDCs.

Antenatal maternal anxiety predicts variations in neural structures implicated in anxiety disorders in newborns.

OBJECTIVE: Antenatal maternal anxiety predicts offspring neurodevelopment and psychopathology, although the degree to which these associations reflect postnatal influences is unclear. To limit this possibility, we assessed newborn neuronal microstructures using diffusion tensor imaging (DTI) and assessed neonatal microstructure variation in relation to antenatal anxiety and in prediction of infant socio-emotional behavior at age 1 year. METHOD: Dyads were drawn from the Growing Up in Singapore Towards Healthy Outcomes (GUSTO) cohort, and included mothers who completed the Speilberger State-Trait Anxiety Inventory (STAI) at 26 weeks gestation (scoring >90, n = 20; scoring <70, n = 34) and their neonates (5-17 days postnatal) who took part in DTI. RESULTS: Antenatal anxiety predicted variation in fractional anisotropy (FA) of regions important to cognitive-emotional responses to stress (i.e., the right insula and dorsolateral prefrontal cortex), sensory processing (e.g., right middle occipital), and socio-emotional function (e.g., the right angular gyrus, uncinate fasciculus, posterior cingulate, and parahippocampus). In a subset of infants with Infant Toddler Socio-Emotional Assessment (ITSEA) data, some of these right lateralized clusters predicted infant internalizing (e.g., insula: ß = 0.511, p = .03) but not externalizing behavior 1 year later, although these analyses failed to withstand the correction for multiple comparisons. CONCLUSION: These findings suggest the need for larger-scale investigations of the role that corticolimbic structures play in regulating cognitive-emotional responses to threat, and potentially in mediating the cross-generational transmission of anxiety, as well as in underscoring the importance of early mother-infant intervention programs.

Prenatal maternal depression associates with microstructure of right amygdala in neonates at birth.

BACKGROUND: Antenatal maternal cortisol levels associate with alterations in the amygdala, a structure associated with emotion regulation, in the offspring. However, because offspring brain and behavior are commonly assessed years after birth, the timing of such maternal influences is unclear. This study aimed to examine the association between antenatal maternal depressive symptomatology and neonatal amygdala volume and microstructure and thus establish evidence for the transgenerational transmission of vulnerability for affective disorders during prenatal development. METHODS: Our study recruited Asian mothers at 10 to 13 weeks pregnancy and assessed maternal depression at 26 weeks gestation using the Edinburgh Postnatal Depression Scale. Structural magnetic resonance imaging and diffusion tensor imaging were performed with 157 nonsedated, 6- to 14-day-old newborns and then analyzed to extract the volume, fractional anisotropy, and axial diffusivity values of the amygdala. RESULTS: Adjusting for household income, maternal age, and smoking exposure, postconceptual age at magnetic resonance imaging, and birth weight, we found significantly lower fractional anisotropy (p = .009) and axial diffusivity (p = .028), but not volume (p = .993), in the right amygdala in the infants of mothers with high compared with those with low-normal Edinburgh Postnatal Depression Scale scores. CONCLUSIONS: The results reveal a significant relation between antenatal maternal depression and the neonatal microstructure of the right amygdala, a brain region closely associated with stress reactivity and vulnerability for mood anxiety disorders. These findings suggest the prenatal transmission of vulnerability for depression from mother to child and that interventions targeting maternal depression should begin early in pregnancy.

Semi-permeable species boundaries in the coral genus Madracis: introgression in a brooding coral system.

Introgressive hybridization is described in several phylogenetic studies of mass-spawning corals. However, the prevalence of this process among brooding coral species is unclear. We used a mitochondrial (mtDNA: nad5) and two nuclear (nDNA: ATPSα and SRP54) intron markers to explore species barriers in the coral genus Madracis and address the role of hybridization in brooding systems. Specimens of six Caribbean Madracis morphospecies were collected from 5 to 60 m depth at Buoy One, Curaçao, supplemented by samples from Aruba, Trinidad & Tobago and Bermuda. Polymerase chain reaction and denaturing gradient gel electrophoresis were coupled to detect distinct alleles within single colonies. The recurrent nDNA phylogenetic non-monophyly among taxa is only challenged by Madracis senaria, the single monophyletic species within the genus. nDNA AMOVAs indicated overall statistical divergence (0.1% significance level) among species but pairwise comparisons of genetic differentiation revealed some gene exchange between Madracis taxa. mtDNA sequences clustered in two main groups representing typical shallow and deep water Madracis species. Madracis pharensis shallow and deep colonies (with threshold at about 23-24 m) clustered in different mtDNA branches, together with their depth-sympatric congenerics. This divergence was repeated for the nDNA (ATPSα) suggestive of distinct M. pharensis depth populations. These matched the vertical distribution of the dinoflagellate symbionts hosted by M. pharensis, with Symbiodinium ITS2 type B7 in the shallows but type B15 in the deep habitats, suggesting symbiont-related disruptive selection. Recurrent non-monophyly of Madracis taxa and high levels of shared polymorphism reflected in ambiguous phylogenetic networks indicate that hybridization is likely to have played a role in the evolution of the genus. Using coalescent forward-in-time simulations, lineage sorting alone was rejected as an explanation to the SRP54 genetic variation contained in Madracis mirabilis and Madracis decactis (species with an old fossil record), showing that introgressive hybridization has taken place between these species, either directly or through the gene pool of other Madracis taxa. Madracis widespread non-monophyly and the absence of statistical divergence between some species suggest that introgressive hybridization plays an important role in the evolution of the genus. Different reproductive traits and symbiont signatures of taxa forming distinct genetic clusters also point to the same conclusion. We suggest that Madracis morphospecies remain recognizable because introgressive hybridization is non-pervasive and/or because disruptive selection is in action.

Variation in symbiont distribution between closely related coral species over large depth ranges.

Symbiotic algae in coral species distributed over a large depth range are confronted with major differences in light conditions. We studied the genetic variation of Symbiodinium in the coral genus Madracis over depth (5-40 m) and at two different colony surface positions. Using polymerase chain reaction-denaturing gradient gel electrophoresis ITS2 nuclear ribosomal DNA analyses, we consistently identified three symbiont genotypes with distributions that reveal patterns of host specificity and depth-based zonation. ITS2 type B7 Symbiodinium is the generalist type, occurring in all zooxanthellate Madracis corals and at all depths. Type B13 is restricted to the shallow water specialist Madracis mirabilis. Type B15 is typical of deep reef environments and replaces B7 in the depth generalist Madracis pharensis. Contrasting with variation over depth, we found strong functional within-colony uniformity in symbiont diversity. Relating symbiont distributions to measured physical factors (irradiance, light spectral distribution, temperature), suggests depth-based ecological function and host specificity for Symbiodinium ITS2 types, even among closely related coral species.

Organic sedimentation and macrofauna as forcing factors in marine benthic nanofagellate communities.

We investigated how benthic nanoflagellate communities in marine sediments respond to sedimentation of organic material and to the presence of macrofaunal organisms in controlled boxcosms. An input of 24 g C m(-2) resulted in a sharp increase in densities, from 93 to 477 × 10(3) flagellates cm(-3) within 11 days. At the onset, this increase was paralleled by enhanced bacterial production and bacterial numbers. When bacterial production collapsed, flagellate ingestion rates, varying from 17 to 67 bact flag(-1) h(-1), were sufficient to control bacterial abundance. The presence of macrofauna accelerated the burst in flagellate densities. With macrofauna the same maximum densities were reached, but later densities dropped to relatively low levels. Macrofaunal bioturbation resulted in higher flagellate densities deeper in the sediment (up to 1200% at 3 cm and up to 460% at 6 cm deep).

Rates of benthic protozoan grazing on free and attached sediment bacteria measured with fluorescently stained sediment.

In order to determine the importance of benthic protozoa as consumers of bacteria, grazing rates have been measured by using monodispersed fluorescently labeled bacteria (FLB). However, high percentages of nongrazing benthic protists are reported in the literature. These are related to serious problems of the monodispersed FLB method. We describe a new method using 5-(4,6-dichlorotriazin-2-yl)-aminofluorescein (DTAF)-stained sediment to measure in situ bacterivory by benthic protists. This method is compared with the monodispersed FLB technique. Our estimates of benthic bacterivory range from 61 to 73 bacteria protist h and are about twofold higher than the results of the monodispersed FLB method. The number of nongrazing protists after incubation for 15 min with DTAF-stained sediment is in agreement with theoretical expectation. We also tested the relative affinity for FLB of protists and discuss the results with respect to a grazing model.

Quantitative centrifugation to extract benthic protozoa from freshwater sediments.

TWO METHODS FOR EXTRACTING PROTISTS FROM FRESHWATER SEDIMENT ARE DESCRIBED: (i) an adapted isopycnic centrifugation technique for sandy and gyttja-like sediments and (ii) a rate zonal centrifugation technique for sediments rich in particulate organic material (litter-like sediments). The recoveries of protists during isopycnic centrifugation in media of several densities were compared. No significant losses in sodium diatrizoate and Percoll were recorded. After known amounts of nanoflagellates were added to azoic sediments, the protists were extracted and counted. For sandy sediments, we found 100% recovery, and for the gyttja-like sediments we found a maximum recovery of 94%. The recovery of protozoa extracted from litter-like sediments, characteristic of littoral systems, depends on a given centrifugal force, on time, and on the dimensions of the flagellates. A recovery model which takes into account cell dimensions and centrifugation characteristics gives the minimum expected recovery.

Allelopathic interaction between a reef coelenterate and benthic algae.

We did in situ experiments to study the influence of a water-borne substance, exuded by the reef anthozoan Condylactis gigantea, on filamentous algae. Algal biomass accumulation on experimental glass slides was significantly inhibited by the exudate. Algal spores and diatoms were present in equal numbers on experimental and control slides, but the exudate inhibited germination of spores and was toxic to developing green, red and brown algae. The algal population on the control slides consisted of early colonizers as well as later successional species and reflected the natural population. The described allelochemic mechanism will be important in interference competition between the anemone and algae. Settling of larvae in supposedly space-limited systems such as reefs is facilitated when algaecovered surfaces are open to settlement.