Sponges as substrata and early life history of the tubulariid Zyzzyzus warreni (Cnidaria: Hydrozoa) in the Sao Sebastiao Channel, Brazil

The hydroid Zyzzyzus warreni is usually found in shallow coastal waters forming aggregations of solitary polyps embedded in demosponges. Early life history transformations and settlement responses by the actinulae of this hydroid were studied in the laboratory using 13 species of sponges and 2 species of algae collected in the Sao Sebastiao Channel (Brazil) as substrata. The absence of oral tentacles and mouth in the actinulae and early events of metamorphosis suggest that these larvae are unable to spend long periods in the plankton and attach quickly near conspecifics when a preferred substratum is encountered. The time required for settlement and the number of elicited settlings indicated four settlement responses: (a) frequent and short-time settlement, in actinulae exposed to Halichondria cebimarensis, Mycale angulosa, M. aff. americana, M. laxissima (skeleton) and Tedania ignis; (b) moderate and delayed settlement, in actinulae exposed to Aplysina caissara, A. fulva, Haliclona melana and M. microsigmatosa; (c) no settlement, in actinulae exposed to Suberites aurantiacus and to the algae Hypnea musciformis and Sargassum cymosum; and (d) lethal response, in actinulae exposed to Amphimedon viridis, Aplysilla rosea, Dragmacidon reticulatum and M. laxissima. These responses indicate a considerable degree of species discrimination by the actinulae and are consistent with substrata used by the hydroid in the natural environment.

Perinatal and early life factors associated with symptoms of depression in Brazilian children

Background: Few studies have been conducted on the association between perinatal and early life factors with childhood depression and results are conflicting. Our aim was to estimate the prevalence and perinatal and early life factors associated with symptoms of depression in children aged 7 to 11 years from two Brazilian birth cohorts. Methods: The study was conducted on 1444 children whose data were collected at birth and at school age, in 1994 and 2004/2005 in Ribeirao Preto, where they were aged 10-11 years and in 1997/98 and 2005/06 in Sao Luis, where children were aged 7-9 years. Depressive symptoms were investigated with the Child Depression Inventory (CDI), categorized as yes (score >= 20) and no (score < 20). Adjusted and non-adjusted prevalence ratios (PR) were estimated by Poisson regression with robust estimation of the standard errors. Results: The prevalence of depressive symptoms was 3.9% (95% CI = 2.5-5.4) in Ribeirao Preto and 13.7% (95% CI = 11.0-16.4) in Sao Luis. In the adjusted analysis, in Ribeirao Preto, low birth weight (PR = 3.98; 95% CI = 1.72-9.23), skilled and semi-skilled manual occupation (PR = 5.30; 95% CI = 1.14-24.76) and unskilled manual occupation and unemployment (PR = 6.65; 95% CI = 1.16-38.03) of the household head were risk factors for depressive symptoms. In Sao Luis, maternal schooling of 0-4 years (PR = 2.39; 95% CI = 1.31-4.34) and of 5 to 8 years (PR = 1.80; 95% CI = 1.08-3.01), and paternal age < 20 years (PR = 1.92; 95% CI = 1.02-3.61), were independent risk factors for depressive symptoms. Conclusions: The prevalence of depressive symptoms was much higher in the less developed city, Sao Luis, than in the more developed city, Ribeirao Preto, and than those reported in several international studies. Low socioeconomic level was associated with depressive symptoms in both cohorts. Low paternal age was a risk factor for depressive symptoms in the less developed city, Sao Luis, whereas low birth weight was a risk factor for depressive symptoms in the more developed city, Ribeirao Preto.

The neonatal immune system: immunomodulation of infections in early life

The innate and adaptive immune responses in neonates are usually functionally impaired when compared with their adult counterparts. The qualitative and quantitative differences in the neonatal immune response put them at risk for the development of bacterial and viral infections, resulting in increased mortality. Newborns often exhibit decreased production of Th1-polarizing cytokines and are biased toward Th2-type responses. Studies aimed at understanding the plasticity of the immune response in the neonatal and early infant periods or that seek to improve neonatal innate immune function with adjuvants or special formulations are crucial for preventing the infectious disease burden in this susceptible group. Considerable studies focused on identifying potential immunomodulatory therapies have been performed in murine models. This article highlights the strategies used in the emerging field of immunomodulation in bacterial and viral pathogens, focusing on preclinical studies carried out in animal models with particular emphasis on neonatal-specific immune deficits.

Social anxiety and negative early life events in university students

INTRODUCTION: There is substantial evidence regarding the impact of negative life events during childhood on the aetiology of psychiatric disorders. We examined the association between negative early life events and social anxiety in a sample of 571 Spanish University students. METHODS: In a cross-sectional survey conducted in 2007, we collected data through a semistructured questionnaire of sociodemographic variables, personal and family psychiatric history, and substance abuse. We assessed the five early negative life events: (i) the loss of someone close, (ii) emotional abuse, (iii) physical abuse, (iv) family violence, and (v) sexual abuse. All participants completed the Liebowitz Social Anxiety Scale. RESULTS: Mean (SD) age was 21 (4.5), 75% female, LSAS score was 40 (DP = 22), 14.2% had a psychiatric family history and 50.6% had negative life events during childhood. Linear regression analyses, after controlling for age, gender, and family psychiatric history, showed a positive association between family violence and social score (p = 0.03). None of the remaining stressors produced a significant increase in LSAS score (p > 0.05). CONCLUSION: University students with high levels of social anxiety presented higher prevalence of negative early life events. Thus, childhood family violence could be a risk factor for social anxiety in such a population.

Early life of the abalone Haliotis tuberculata coccínea : development, settlement and growth

Programa de doctorado: Acuicultura

Genetic dynamics across early life stages in the tropical tree Prunus africana (Rosaceae)

In many plant species, the genetic template of early life-stages is formed by animal-mediated pollination and seed dispersal and has profound impact on further recruitment and population dynamics. Understanding the impact of pollination and seed dispersal on genetic patterns is a central issue in plant population biology. In my thesis, I investigated (i) contemporary dispersal and gene flow distances as well as (ii) genetic diversity and spatial genetic structure (SGS) across subsequent recruitment stages in a population of the animal-pollinated and dispersed tree Prunus africana in Kakamega Forest, West Kenya. Using microsatellite markers and parentage analyses, I inferred distances of pollen dispersal (father-to-mother), seed dispersal/maternal gene flow (mother-to-offspring) as well as paternal gene flow (father-to-offspring) for four early life stages of the species (seeds and fruits, current year seedlings, seedlings ≤ 3yr, seedlings > 3yr). Distances of pollen and seed dispersal as well as paternal gene flow were significantly shorter than expected from the spatial arrangement of trees and sampling plots. They were not affected by the density of conspecific trees in the surrounding. At the propagule stage, mean pollen dispersal distances were considerably (23-fold) longer than seed dispersal distances, and paternal gene flow distances exceeded maternal gene flow by a factor of 25. Seed dispersal distances were remarkably restricted, potentially leading to a strong initial SGS. The initial genetic template created by pollination and seed dispersal was extensively altered during later recruitment stages. Potential Janzen-Connell effects led to markedly increasing distances between offspring and both parental trees in older life stages. This showed that distance and density-dependent mortality factors are not exclusively related to the mother tree, but also to the father. Across subsequent recruitment stages, the pollen to seed dispersal ratio and the paternal to maternal gene flow ratio dropped to 2.1 and 3.4, respectively, in seedlings > 3yr. The relative changes in effective pollen dispersal, seed dispersal, and paternal gene flow distances across recruitment stages elucidate the mechanisms affecting the contribution of the two processes pollen and seed dispersal to overall gene flow. Using the same six microsatellite loci, I analyzed genetic diversity and SGS across five life stages, from seed rain to adults. Levels of genetic diversity within the studied P. africana population were comparable to other Prunus species and did not vary across life stages. In congruence with the short seed dispersal distances, I found significant SGS in all life stages. SGS decreased from seed and early seedling stages to older juvenile stages, and it was higher in adults than in late juveniles of the next generation. A comparison of the data with direct assessments of contemporary gene flow patterns indicate that distance- or density-dependent mortality, potentially due to Janzen-Connell effects, led to the initial decrease in SGS. Intergeneration variation in SGS could have been driven by variation in demographic processes, the effect of overlapping generations, and local selection processes. Overall, my study showed that complex sequential processes during recruitment contribute to the spatial genetic structure of tree populations. It highlights the importance of a multistage perspective for a comprehensive understanding of the impact of animal-mediated pollen and seed dispersal on spatial population dynamics and genetic patterns of trees.

Human coronavirus NL63 associated with lower respiratory tract symptoms in early life

Coronavirus NL63 has been identified as a new member of the coronavirus genus, but its role as a cause of respiratory disease needs to be established. We studied the first episode of lower respiratory tract symptoms in a cohort of healthy neonates. NL63 was identified in 6 (7%) of 82 cases and was as frequent as other coronaviruses (9%). NL63 was recovered at the onset of symptoms and was cleared within 3 weeks in half of the cases. Our data suggests that coronavirus NL63 causes lower respiratory tract symptoms and is acquired in early life.

Dispersal Modeling of Fish Early Life Stages: Sensitivity with Application to Atlantic Cod in the Western Gulf of Maine

As an initial step in establishing mechanistic relationships between environmental variability and recruitment in Atlantic cod Gadhus morhua along the coast of the western Gulf of Maine, we assessed transport success of larvae from major spawning grounds to nursery areas with particle tracking using the unstructured grid model FVCOM (finite volume coastal ocean model). In coastal areas, dispersal of early planktonic life stages of fish and invertebrate species is highly dependent on the regional dynamics and its variability, which has to be captured by our models. With state-of-the-art forcing for the year 1995, we evaluate the sensitivity of particle dispersal to the timing and location of spawning, the spatial and temporal resolution of the model, and the vertical mixing scheme. A 3 d frequency for the release of particles is necessary to capture the effect of the circulation variability into an averaged dispersal pattern of the spawning season. The analysis of sensitivity to model setup showed that a higher resolution mesh, tidal forcing, and current variability do not change the general pattern of connectivity, but do tend to increase within-site retention. Our results indicate strong downstream connectivity among spawning grounds and higher chances for successful transport from spawning areas closer to the coast. The model run for January egg release indicates 1 to 19 % within-spawning ground retention of initial particles, which may be sufficient to sustain local populations. A systematic sensitivity analysis still needs to be conducted to determine the minimum mesh and forcing resolution that adequately resolves the complex dynamics of the western Gulf of Maine. Other sources of variability, i.e. large-scale upstream forcing and the biological environment, also need to be considered in future studies of the interannual variability in transport and survival of the early life stages of cod.

Horn Growth and Reproduction in a Long-Lived Male Mammal: No Compensation for Poor Early-Life Horn Growth

Secondary sexual traits in males of polygynous species are important determinants of reproductive success. It is, however, unknown if and how the development of continuously growing traits at different life-stages is related to reproduction in long-lived male mammals. In this study, we evaluated the relationship of early and late horn growth on social status and reproduction in long-lived male Alpine ibex (Capra ibex). For this, we analysed individual horn growth and assessed its effect on dominance and reproduction. No evidence was detected for compensatory horn growth, as late-life horn growth positively depended on early-life horn growth in males. Still, individuals with longer horn segments grown during early adulthood experienced a stronger age-dependent length decline in annual horn growth during the late development. Accordingly, a divergence between individual growth potential and realized horn growth late in life has to be assumed. Residual age-specific horn length and length of early grown horn segments both positively affected dominance and reproductive success, whereas, contrary to our expectation, no significant effect of the length of horn segments grown during the late development was detected. Suspected higher somatic costs incurred by high-quality males during their late development might at least partly be responsible for this finding. Overall, our study suggests that the total length of horns and their early development in long-lived male Alpine ibex is a reliable indicator of reproductive success and that individuals may be unable to compensate for poor early-life growth performance at a later point in life.

Personal Reminiscences of my early life

by Kaufmann Kohler