Gastrin/CCK-like immunoreactivity in the nervous system of coelenterates

Using immunocytochemistry, gastrin/CCK-like immunoreactivity is found in sensory nerve cells in the ectoderm of the mouth region of hydra and in nerve cells in the endoderm of all body regions of the sea anemone tealia. These results are corroborated by radioimmunoassay: One hydra contains at least 5 fmole and one tealia at least 2 nmole gastrin/CCK-like immunoreactivity. Reactivities towards gastrin and CCK antisera with different specificities suggest that the coelenterate gastrin/CCK-like peptide contains the C-terminal amino-acid sequence common to mammalian gastrin and CCK. In addition the radioimmunochemical data indicate that the coelenterate peptide also contains an amino-acid sequence that resembles the sequence 20-30 of porcine CCK-33, but that no other sequences of gastrin are present. Thus, it is probably more CCK-like than gastrin-like.     

Bombesin-like immunoreactivity in the nervous system of hydra

Summary With immunocytochemical methods, nerve cells have been detected in Hydra attenuata containing bombesin-like immunoreactivity. These nerve cells are located in the ectoderm of all body regions of the animal and are especially abundant in basal disk and tentacles. Radioimmunoassay of extracts of hydra demonstrated at least 0.2 pmol/g wet weight of bombesinlike immunoreactivity. The immunoreactive material elutes from Sephadex G-50 in a similar position to synthetic bombesin. The data show that bombesin-like peptides are among the phylogenetically oldest neuropeptides found so far.     

Algorithm of OMA for large-scale orthology inference

Since the publication of our article (Roth, Gonnet, and Dessimoz: BMC Bioinformatics 2008 9: 518), we have noticed several errors, which we correct in the following.     

Identification of four evolutionarily related G protein-coupled receptors from the malaria mosquito Anopheles gambiae

The mosquito Anopheles gambiae is an important vector for malaria, which is one of the most serious human parasitic diseases in the world, causing up to 2.7 million deaths yearly. To contribute to our understanding of A. gambiae and to the transmission of malaria, we have now cloned four evolutionarily related G protein-coupled receptors (GPCRs) from this mosquito and expressed them in Chinese hamster ovary cells. After screening of a library of thirty-three insect or other invertebrate neuropeptides and eight biogenic amines, we could identify (de-orphanize) three of these GPCRs as: an adipokinetic hormone (AKH) receptor (EC₅₀ for A. gambiae AKH, 3 × 10⁻⁹ M), a corazonin receptor (EC₅₀ for A. gambiae corazonin, 4 × 10⁻⁹ M), and a crustacean cardioactive peptide (CCAP) receptor (EC₅₀ for A. gambiae CCAP, 1 × 10⁻⁹ M). The fourth GPCR remained an orphan, although its close evolutionary relationship to the A. gambiae and other insect AKH receptors suggested that it is a receptor for an AKH-like peptide. This is the first published report on evolutionarily related AKH, corazonin, and CCAP receptors in mosquitoes.     

PIDDosome‐induced p53‐dependent ploidy restriction facilitates hepatocarcinogenesis

Polyploidization frequently precedes tumorigenesis but also occurs during normal development in several tissues. Hepatocyte ploidy is controlled by the PIDDosome during development and regeneration. This multi‐protein complex is activated by supernumerary centrosomes to induce p53 and restrict proliferation of polyploid cells, otherwise prone for chromosomal instability. PIDDosome deficiency in the liver results in drastically increased polyploidy. To investigate PIDDosome‐induced p53‐activation in the pathogenesis of liver cancer, we chemically induced hepatocellular carcinoma (HCC) in mice. Strikingly, PIDDosome deficiency reduced tumor number and burden, despite the inability to activate p53 in polyploid cells. Liver tumors arise primarily from cells with low ploidy, indicating an intrinsic pro‐tumorigenic effect of PIDDosome‐mediated ploidy restriction. These data suggest that hyperpolyploidization caused by PIDDosome deficiency protects from HCC. Moreover, high tumor cell density, as a surrogate marker of low ploidy, predicts poor survival of HCC patients receiving liver transplantation. Together, we show that the PIDDosome is a potential therapeutic target to manipulate hepatocyte polyploidization for HCC prevention and that tumor cell density may serve as a novel prognostic marker for recurrence‐free survival in HCC patients.     

SIMPLE: implementation of recommendations from international evidence-based guidelines on caesarean sections in the Netherlands. Protocol for a controlled before and after study

Background

Caesarean section (CS) rates are rising worldwide. In the Netherlands, the most significant rise is observed in healthy women with a singleton in vertex position between 37 and 42 weeks gestation, whereas it is doubtful whether an improved outcome for the mother or her child was obtained. It can be hypothesized that evidence-based guidelines on CS are not implemented sufficiently. Therefore, the present study has the following objectives: to develop quality indicators on the decision to perform a CS based on key recommendations from national and international guidelines; to use the quality indicators in order to gain insight into actual adherence of Dutch gynaecologists to guideline recommendations on the performance of a CS; to explore barriers and facilitators that have a direct effect on guideline application regarding CS; and to develop, execute, and evaluate a strategy in order to reduce the CS incidence for a similar neonatal outcome (based on the information gathered in the second and third objectives).

Methods

An independent expert panel of Dutch gynaecologists and midwives will develop a set of quality indicators on the decision to perform a CS. These indicators will be used to measure current care in 20 hospitals with a population of 1,000 women who delivered by CS, and a random selection of 1,000 women who delivered vaginally in the same period. Furthermore, by interviewing healthcare professionals and patients, the barriers and facilitators that may influence the decision to perform a CS will be measured. Based on the results, a tailor-made implementation strategy will be developed and tested in a controlled before-and-after study in 12 hospitals (six intervention, six control hospitals) with regard to effectiveness, experiences, and costs.

Discussion

This study will offer insight into the current CS care and into the hindering and facilitating factors influencing obstetrical policy on CS. Furthermore, it will allow definition of patient categories or situations in which a tailor-made implementation strategy will most likely be meaningful and cost effective, without negatively affecting the outcome for mother and child.

Trial registration

http://www.clinicaltrials.gov: NCT01261676     

Aggravation of myocardial dysfunction by injurious mechanical ventilation in LPS-induced pneumonia in rats

Background

Mechanical ventilation (MV) may cause ventilator-induced lung injury (VILI) and may thereby contribute to fatal multiple organ failure. We tested the hypothesis that injurious MV of lipopolysaccharide (LPS) pre-injured lungs induces myocardial inflammation and further dysfunction ex vivo, through calcium (Ca²⁺)-dependent mechanism.

Materials and methods

N = 35 male anesthetized and paralyzed male Wistar rats were randomized to intratracheal instillation of 2 mg/kg LPS or nothing and subsequent MV with lung-protective settings (low tidal volume (V_t) of 6 mL/kg and 5 cmH₂O positive end-expiratory pressure (PEEP)) or injurious ventilation (high V_t of 19 mL/kg and 1 cmH₂O PEEP) for 4 hours. Myocardial function ex vivo was evaluated in a Langendorff setup and Ca²⁺ exposure. Key mediators were determined in lung and heart at the mRNA level.

Results

Instillation of LPS and high V_t MV impaired gas exchange and, particularly when combined, increased pulmonary wet/dry ratio; heat shock protein (HSP)70 mRNA expression also increased by the interaction between LPS and high V_t MV. For the heart, C-X-C motif ligand (CXCL)1 and Toll-like receptor (TLR)2 mRNA expression increased, and ventricular (LV) systolic pressure, LV developed pressure, LV +dP/dt_max and contractile responses to increasing Ca²⁺ exposure ex vivo decreased by LPS. High V_t ventilation aggravated the effects of LPS on myocardial inflammation and dysfunction but not on Ca²⁺ responses.

Conclusions

Injurious MV by high V_t aggravates the effects of intratracheal instillation of LPS on myocardial dysfunction, possibly through enhancing myocardial inflammation via pulmonary release of HSP70 stimulating cardiac TLR2, not involving Ca²⁺ handling and sensitivity.     

Identification of the Drosophila and Tribolium receptors for the recently discovered insect RYamide neuropeptides

One year ago, we discovered a new family of insect RYamide neuropeptides, which has the C-terminal consensus sequence FFXXXRYamide, and which is widely occurring in most insects, including the fruitfly Drosophila melanogaster and the red flour beetle Tribolium castaneum (F. Hauser et al., J. Proteome Res. 9 (2010) 5296–5310). Here, we identify a Drosophila G-protein-coupled receptor (GPCR) coded for by gene CG5811 and its Tribolium GPCR ortholog as insect RYamide receptors. The Drosophila RYamide receptor is equally well activated (EC₅₀, 1 × 10⁻⁹ M) by the two Drosophila RYamide neuropeptides: RYamide-1 (PVFFVASRYamide) and RYamide-2 (NEHFFLGSRYamide), both contained in a preprohormone coded for by gene CG40733. The Tribolium receptor shows a somewhat higher affinity to Tribolium RYamide-2 (ADAFFLGPRYamide; EC₅₀, 5 × 10⁻⁹ M) than to Tribolium RYamide-1 (VQNLATFKTMMRYamide; EC₅₀, 7 × 10⁻⁸ M), which might be due to the fact that the last peptide does not completely follow the RYamide consensus sequence rule. There are other neuropeptides in insects that have similar C-terminal sequences (RWamide or RFamide), such as the FMRFamides, sulfakinins, myosuppressins, neuropeptides F, and the various short neuropeptides F. Amazingly, these neuropeptides show no cross-reactivity to the Tribolium RYamide receptor, while the Drosophila RYamide receptor is only very slightly activated by high concentrations (>10⁻⁶ M) of neuropeptide F and short neuropeptide F-1, showing that the two RYamide receptors are quite specific for activation by insect RYamides, and that the sequence FFXXXRYamide is needed for effective insect RYamide receptor activation. Phylogenetic tree analyses and other amino acid sequence comparisons show that the insect RYamide receptors are not closely related to any other known insect or invertebrate/vertebrate receptors, including mammalian neuropeptide Y and insect neuropeptide F and short neuropeptide F receptors. Gene expression data published in Flybase (www.flybase.org) show that the Drosophila CG5811 gene is significantly expressed in the hindgut of adult flies, suggesting a role of insect RYamides in digestion or water reabsorption.     

RNA interference in Lepidoptera: an overview of successful and unsuccessful studies and implications for experimental design

Gene silencing through RNA interference (RNAi) has revolutionized the study of gene function, particularly in non-model insects. However, in Lepidoptera (moths and butterflies) RNAi has many times proven to be difficult to achieve. Most of the negative results have been anecdotal and the positive experiments have not been collected in such a way that they are possible to analyze. In this review, we have collected detailed data from more than 150 experiments including all to date published and many unpublished experiments. Despite a large variation in the data, trends that are found are that RNAi is particularly successful in the family Saturniidae and in genes involved in immunity. On the contrary, gene expression in epidermal tissues seems to be most difficult to silence. In addition, gene silencing by feeding dsRNA requires high concentrations for success. Possible causes for the variability of success in RNAi experiments in Lepidoptera are discussed. The review also points to a need to further investigate the mechanism of RNAi in lepidopteran insects and its possible connection to the innate immune response. Our general understanding of RNAi in Lepidoptera will be further aided in the future as our public database at http://insectacentral.org/RNAi will continue to gather information on RNAi experiments.