The Molecular Machinery of Gametogenesis in Geodia Demosponges (Porifera): Evolutionary Origins of a Conserved Toolkit across Animals

All animals are capable of undergoing gametogenesis. The ability of forming haploid cells from diploid cells through meiosis and recombination appeared early in eukaryotes, whereas further gamete differentiation is mostly a metazoan signature. Morphologically, the gametogenic process presents many similarities across animal taxa, but little is known about its conservation at the molecular level. Porifera are the earliest divergent animals and therefore are an ideal phylum to understand evolution of the gametogenic toolkits. Although sponge gametogenesis is well known at the histological level, the molecular toolkits for gamete production are largely unknown. Our goal was to identify the genes and their expression levels which regulate oogenesis and spermatogenesis in five gonochoristic and oviparous species of the genus Geodia, using both RNAseq and proteomic analyses. In the early stages of both female and male gametogenesis, genes involved in germ cell fate and cell-renewal were upregulated. Then, molecular signals involved in retinoic acid pathway could trigger the meiotic processes. During later stages of oogenesis, female sponges expressed genes involved in cell growth, vitellogenesis, and extracellular matrix reassembly, which are conserved elements of oocyte maturation in Metazoa. Likewise, in spermatogenesis, genes regulating the whole meiotic cycle, chromatin compaction, and flagellum axoneme formation, that are common across Metazoa were overexpressed in the sponges. Finally, molecular signals possibly related to sperm capacitation were identified during late stages of spermatogenesis for the first time in Porifera. In conclusion, the activated molecular toolkit during gametogenesis in sponges was remarkably similar to that deployed during gametogenesis in vertebrates.     

Taxonomy,biogeography and DNA barcodes of Geodia species (Porifera,Demospongiae, Tetractinellida) in the Atlantic boreo‐arctic region

Geodia species north of 60°N in the Atlantic appeared in the literature for the first time when Bowerbank described Geodia barretti and G. macandrewii in 1858 from western Norway. Since then, a number of species have been based on material from various parts of the region: G. simplex, Isops phlegraei, I. pallida, I. sphaeroides, Synops pyriformis, G. parva, G. normani, G. atlantica, Sidonops mesotriaena (now called G. hentscheli), and G. simplicissima. In addition to these 12 nominal species, four species described from elsewhere are claimed to have been identified in material from the northeast Atlantic, namely G. nodastrella and G. cydonium (and its synonyms Cydonium muelleri and Geodia gigas). In this paper, we revise the boreo‐arctic Geodia species using morphological, molecular, and biogeographical data. We notably compare northwest and northeast Atlantic specimens. Biological data (reproduction, biochemistry, microbiology, epibionts) for each species are also reviewed. Our results show that there are six valid species of boreo‐arctic Atlantic Geodia while other names are synonyms or mis‐identifications. Geodia barretti, G. atlantica, G. macandrewii, and G. hentscheli are well established and widely distributed. The same goes for Geodia phlegraei, but this species shows a striking geographical and bathymetric variation, which led us to recognize two species, G. phlegraei and G. parva (here resurrected). Some Geodia are arctic species (G. hentscheli, G. parva), while others are typically boreal (G. atlantica, G. barretti, G. phlegraei, G. macandrewii). No morphological differences were found between specimens from the northeast and northwest Atlantic, except for G. parva. The Folmer cytochrome oxidase subunit I (COI) fragment is unique for every species and invariable over their whole distribution range, except for G. barretti which had two haplotypes. 18S is unique for four species but cannot discriminate G. phlegraei and G. parva. Two keys to the boreo‐arctic Geodia are included, one based on external morphology, the other based on spicule morphology. © 2013 The Linnean Society of London     

Efficacy of plant extracts and effect of seed soaking duration on treatment of sorghum seed naturally infected by Colletotrichum graminicola and Phoma sorghina

The study was undertaken to evaluate the effectiveness of the aqueous extracts ofBalanites aegyptiaca (L.) Del., Cymbopogon citratus D. C. Stapf, Cassia occidentalis L. and Portulaca oleracea L. different durations of extracts maceration (6, 12, 24 and 48 h) and different durations of soaking seed in plant extracts (6, 12 and 24 h). All the plant extracts tested significantly reduced the infection rate by C. graminicola and P. sorghina except for the extract of C.occidentalis which was not efficient against P. sorghina. Extract of C. citratus and P. oleracea were more efficient on the reduction of the infection rate by C.graminicola. Those of B. aegyptiaca and C. citratus were the most efficient in reducing infection by P. sorghina. Long period of soaking and macerate were favourable in increasing of the antifungal efficiency of the extract.     

Mercury exposure in an endangered seabird: long-term changes and relationships with trophic ecology and breeding success

Mercury (Hg) is an environmental contaminant which, at high concentrations, can negatively influence avian physiology and demography. Albatrosses (Diomedeidae) have higher Hg burdens than all other avian families. Here, we measure total Hg (THg) concentrations of body feathers from adult grey-headed albatrosses (Thalassarche chrysostoma) at South Georgia. Specifically, we (i) analyse temporal trends at South Georgia (1989–2013) and make comparisons with other breeding populations; (ii) identify factors driving variation in THg concentrations and (iii) examine relationships with breeding success. Mean ± s.d. feather THg concentrations were 13.0 ± 8.0 µg g⁻¹ dw, which represents a threefold increase over the past 25 years at South Georgia and is the highest recorded in the Thalassarche genus. Foraging habitat, inferred from stable isotope ratios of carbon (δ¹³C), significantly influenced THg concentrations—feathers moulted in Antarctic waters had far lower THg concentrations than those moulted in subantarctic or subtropical waters. THg concentrations also increased with trophic level (δ¹⁵N), reflecting the biomagnification process. There was limited support for the influence of sex, age and previous breeding outcome on feather THg concentrations. However, in males, Hg exposure was correlated with breeding outcome—failed birds had significantly higher feather THg concentrations than successful birds. These results provide key insights into the drivers and consequences of Hg exposure in this globally important albatross population.     

Thyroid carcinoma in children and adolescents: a retrospective review

ObjectiveTo describe clinical presentation, preoperative study, intervention, histology, surgical complications and follow-up characteristics, and survival in patients with thyroid carcinoma (TC) with less than 18 years at presentation.Material and methodsretrospective analysis of clinical data of all children and adolescents followed in S. João Hospital from January 1, 2000 to March 31, 2010 with histologic diagnosis of TC.ResultsTwenty-three patients were identified, 19 girls, and 4 boys. Median age at presentation was 17.0 years. Annual incidence was 2.3 cases/year. The main presenting symptom was a solitary thyroid nodule (60.8%). Three (13%) patients had risk factors for TC, 2 of the 3 had previous cervical irradiation. The other was a smoker. Total thyroidectomy was performed in 16 (69.6%), and 10 patients underwent a second surgical procedure. Four (17.4%) patients had postoperative complications. Histologic examination revealed differentiated TC in all, papillary thyroid carcinoma (PTC) in 86.9%, follicular carcinoma in the remaining. All patients received thyroxine suppressive therapy and 20 underwent therapeutic radioactive iodine (¹³¹I). During follow-up (7.1 years), 7 out of the 23 patients presented new metastases and needed new treatment. All patients are currently alive.ConclusionsTC is a reality in pediatric population, thyroid routine examination should take part in all clinical examination in children and adolescents.     

Temperature and pCO2 effect on the bioaccumulation of radionuclides and trace elements in the eggs of the common cuttlefish,Sepia officinalis

The increasing release of CO₂ by human activities leads to ocean acidification and global warming. Both those consequences (i.e., increase in seawater pCO₂ and temperature) may drastically affect the physiology of marine organisms. The effects of low pH and elevated temperature on the bioaccumulation of radionuclides (²⁴¹Am, ¹³⁴Cs) and trace elements (⁶⁰Co, ⁵⁴Mn or ⁷⁵Se) were studied during the embryonic development of the common cuttlefish Sepia officinalis. The lowered accumulation of essential ⁶⁰Co and ⁵⁴Mn with decreasing pH was larger at 16 °C than at 19 °C. Se was not detected in the embryo whereas it penetrated through the eggshell, suggesting that an alternative pathway ensures the supply of this essential metal for the embryo. ²⁴¹Am was totally retained by the eggshell irrespective of pH and temperature. Finally, the amount of Cs found in the peri-vitelline fluid increased with decreasing pH likely because of an enhanced swelling of the cuttlefish egg under elevated CO₂.     

Long-term exposure to LPS enhances the rate of stimulated exocytosis and surfactant secretion in alveolar type II cells and upregulates P2Y2 receptor expression

Bacterial LPS is a potent proinflammatory molecule. In the lungs, LPS induces alterations in surfactant pool sizes and phospholipid (PL) contents, although direct actions of LPS on the alveolar type II cells (AT II) are not yet clear. For this reason, we studied short- and long-term effects of LPS on basal and agonist-stimulated secretory responses of rat AT II by using Ca(2+) microfluorimetry, a microtiter plate-based exocytosis assay, by quantitating PL and (3)H-labeled choline released into cell supernatants and by using quantitative PCR and Western blot analysis. Long term, but not short term, exposures to LPS led to prolonged ATP-induced Ca(2+) signals and an increased rate in vesicle fusions with an augmented release of surfactant PL. Most notably, the stimulatory effect of LPS was ATP-dependent and may be mediated by the upregulation of the purinergic receptor subtype P2Y(2). Western blot analysis confirmed higher levels of P2Y(2), and suramin, a P2Y receptor antagonist, was more effective in LPS-treated cells. From these observations, we conclude that LPS, probably via Toll-like receptor-4, induces a time-dependent increase in P2Y(2) receptors, which, by yet unknown mechanisms, leads to prolonged agonist-induced Ca(2+) responses that trigger a higher activity in vesicle fusion and secretion. We further conclude that chronic exposure to endotoxin sensitizes AT II to increase the extracellular surfactant pool, which aids in the pulmonary host defense mechanisms.     

Preliminary findings of a randomized trial of non-pharmaceutical interventions to prevent influenza transmission in households

Background

There are sparse data on whether non-pharmaceutical interventions can reduce the spread of influenza. We implemented a study of the feasibility and efficacy of face masks and hand hygiene to reduce influenza transmission among Hong Kong household members.

Methodology/Principal Findings

We conducted a cluster randomized controlled trial of households (composed of at least 3 members) where an index subject presented with influenza-like-illness of <48 hours duration. After influenza was confirmed in an index case by the QuickVue Influenza A+B rapid test, the household of the index subject was randomized to 1) control or 2) surgical face masks or 3) hand hygiene. Households were visited within 36 hours, and 3, 6 and 9 days later. Nose and throat swabs were collected from index subjects and all household contacts at each home visit and tested by viral culture. The primary outcome measure was laboratory culture confirmed influenza in a household contact; the secondary outcome was clinically diagnosed influenza (by self-reported symptoms). We randomized 198 households and completed follow up home visits in 128; the index cases in 122 of those households had laboratory-confirmed influenza. There were 21 household contacts with laboratory confirmed influenza corresponding to a secondary attack ratio of 6%. Clinical secondary attack ratios varied from 5% to 18% depending on case definitions. The laboratory-based or clinical secondary attack ratios did not significantly differ across the intervention arms. Adherence to interventions was variable.

Conclusions/Significance

The secondary attack ratios were lower than anticipated, and lower than reported in other countries, perhaps due to differing patterns of susceptibility, lack of significant antigenic drift in circulating influenza virus strains recently, and/or issues related to the symptomatic recruitment design. Lessons learnt from this pilot have informed changes for the main study in 2008.

Trial Registration

ClinicalTrials.gov {"type":"clinical-trial","attrs":{"text":"NCT00425893","term_id":"NCT00425893"}}NCT00425893 HKClinicalTrials.com HKCTR-365