Do male golden egg bugs carry eggs they have fertilized? A microsatellite analysis

In the golden egg bug, Phyllomorpha laciniata (Heteroptera,Coreidae), both males and females carry eggs on their back.Although females cannot carry their own eggs, males may carryeggs that they have fertilized. If males carry eggs they havefertilized, their behavior may be interpreted as paternal care.In this article, we provide genetic data for paternity assignmentof eggs carried by 40 males collected from the field. The malesand the eggs were typed by using four highly polymorphic microsatelliteDNA markers. Out of the 247 eggs typed, 87% were excluded fromthe father-offspring relationship based on single-locus (leastconservative exclusion) mismatches. Under the more conservative(exclusion by at least two single locus mismatches) method,78% of the eggs were nonpaternal. Relatedness estimates furthersupported our paternity analyses. The average relatedness ofthe eggs to the carrying males was low (b_em = -0.052 ±0.024 SE). Within the population, males were unrelated to eachother (b_mm = -0.004 ± 0.0002 SE), as were the eggs carriedby individual males (b_eggs = -0.004 ± 0.0001 SE). Thisfirst genetic study on the breeding system of the golden eggbugs did not find any support for the claim that egg carryingfunctioned as paternal care, nor did it support kin selectionas explanation for conspecific egg carrying.     

Impact of substrates acclimation strategy on simultaneous biodegradation of hydrogen sulfide and ammonia

Three columns were differentiated with feeding mixture of H₂S and NH₃ (MFC), feeding NH₃ followed by H₂S (NFC), and feeding H₂S followed by NH₃ (SFC). Removal performance, biodegradation capacity and microbial community structures in the three columns were compared. The results show that NFC has a shorter acclimation period for the removal of NH₃ gas and nitrification than MFC. Under the high loading of H₂S and NH₃ at 164 and 82 g m⁻³ h⁻¹, respectively, NFC exhibited high removal efficiency of NH₃ (>95%) while the removal efficiencies were obtained at 63 and 75% in MFC and SFC, respectively. The removal of NH₃ gas in NFC was significantly attributed to nitrification (over 50%), while adsorption and chemical reaction contributed to the removal of NH₃ in MFC and SFC. The different biodegradation capacities of NH₃ could be due to the dissimilarity in the microbial population presented in each column.     

Properties of phenol-removal aerobic granules during normal operation and shock loading

The physical structure and activity of aerobic granules, and the succession of bacterial community within aerobic granules under constant operational conditions and shock loading were investigated in one sequencing batch reactor over ten months. While the maturation phase of the granulation process began on day 30, the structure of microbial community changed markedly until after three months of reactor operation under constant conditions with a loading rate of 1.5 g phenol L⁻¹ day⁻¹. A shock loading of 6.0 g phenol L⁻¹ day⁻¹ from days 182–192 led to divergence of bacterial community, an inhibition of the biomass activity, and a decrease in phenol removal rate in the reactor. However, phenol was still completely removed under this disturbance. After the shock loading, the mean sizes of aerobic granules increased, and the activity of the microbial population within the granules decreased, although there appeared highly resilient for the dominant bacterial community of aerobic granules which mainly included β-Proteobacteria. Correlation analysis suggested that biomass concentration and biomass loading were significantly related to the community composition of aerobic granules during the whole operational period. The development of a relatively stable bacterial community in aerobic granules implied that those distinct dominant microbes in aerobic granules were favorably selected and proliferated under the operational conditions.     

A Vertebrate-Specific Chp-PAK-PIX Pathway Maintains E-Cadherin at Adherens Junctions during Zebrafish Epiboly

Background

In early vertebrate development, embryonic tissues modulate cell adhesiveness and acto-myosin contractility to correctly orchestrate the complex processes of gastrulation. E-cadherin (E-cadh) is the earliest expressed cadherin and is needed in the mesendodermal progenitors for efficient migration [1], [2]. Regulatory mechanisms involving directed E-cadh trafficking have been invoked downstream of Wnt11/5 signaling [3]. This non-canonical Wnt pathway regulates RhoA-ROK/DAAM1 to control the acto-myosin network. However, in this context nothing is known of the intracellular signals that participate in the correct localization of E-cadh, other than a need for Rab5c signaling [3].

Methodology/Principal Findings

By studying loss of Chp induced by morpholino-oligonucleotide injection in zebrafish, we find that the vertebrate atypical Rho-GTPase Chp is essential for the proper disposition of cells in the early embryo. The underlying defect is not leading edge F-actin assembly (prominent in the cells of the envelope layer), but rather the failure to localize E-cadh and β-catenin at the adherens junctions. Loss of Chp results in delayed epiboly that can be rescued by mRNA co-injection, and phenocopies zebrafish E-cadh mutants [4], [5]. This new signaling pathway involves activation of an effector kinase PAK, and involvement of the adaptor PAK-interacting exchange factor PIX. Loss of signaling by any of the three components results in similar underlying defects, which is most prominent in the epithelial-like envelope layer.

Conclusions/Significance

Our current study uncovers a developmental pathway involving Chp/PAK/PIX signaling, which helps co-ordinate E-cadh disposition to promote proper cell adhesiveness, and coordinate movements of the three major cell layers in epiboly. Our data shows that without Chp signaling, E-cadh shifts to intracellular vesicles rather than the adhesive contacts needed for directed cell movement. These events may mirror the requirement for PAK2 signaling essential for the proper formation of the blood-brain barrier [6], [7].     

Supreme™ laryngeal mask airway use in general Anesthesia for category 2 and 3 Cesarean delivery: a prospective cohort study

Background

The Supreme? laryngeal mask airway (SLMA) is a single-use LMA with double lumen design that allows separation of the respiratory and the alimentary tract, hence potentially reducing the gastric volume and risk of aspiration. The purpose of this prospective cohort study is to evaluate the the role of the SLMA as an airway technique for women undergoing category 2 and 3 Cesarean delivery under general anesthesia.

Methods

We recruited 584 parturients who underwent category 2 or 3 Cesarean delivery under general anesthesia, in which 193 parturients underwent category 2 and 391 parturients underwent category 3 Cesarean delivery. The primary outcome was insertion success rate at 1st attempt in SLMA insertion. The secondary outcomes included anaesthetic, obstetric outcomes and maternal side effects associated with airway device.

Results

The 1st attempt insertion success rate was 98.3%, while the overall insertion success rate was 100%. The mean (Standard deviation) time to effective ventilation was 15.6 (4.4) seconds. Orogastric tube insertion was successful at the 1st attempt in all parturients. There was no clinical evidence of aspiration or regurgitation. No episodes of hypoxemia, laryngospasm or bronchospasm were observed intra-operatively. The incidence of complications was low and with good maternal satisfaction reported.

Conclusions

The SLMA could be an alternative effective airway in category 2 and 3 parturients emergency Cesarean Delivery under general anesthesia in a carefully-selected obstetric population.

Trial registration

Clinical Trials Registration: Clinicaltrials.gov Registration NCT02026882. Registered on December 31, 2013.

     

Characterisation of novel functionality within the Blastocystis tryptophanase gene

In recent years, the human gut microbiome has been recognised to play a pivotal role in the health of the host. Intestinal homeostasis relies on this intricate and complex relationship between the gut microbiota and the human host. While much effort and attention has been placed on the characterization of the organisms that inhabit the gut microbiome, the complex molecular cross-talk between the microbiota could also exert an effect on gastrointestinal conditions. Blastocystis is a single-cell eukaryotic parasite of emerging interest, as its beneficial or pathogenic role in the microbiota has been a subject of contention even to-date. In this study, we assessed the function of the Blastocystis tryptophanase gene (BhTnaA), which was acquired by horizontal gene transfer and likely to be of bacterial origin within Blastocystis. Bioinformatic analysis and phylogenetic reconstruction revealed distinct divergence of BhTnaA versus known bacterial homologs. Despite sharing high homology with the E. coli tryptophanase gene, we show that Blastocystis does not readily convert tryptophan into indole. Instead, BhTnaA preferentially catalyzes the conversion of indole to tryptophan. We also show a direct link between E. coli and Blastocystis tryptophan metabolism: In the presence of E. coli, Blastocystis ST7 is less able to metabolise indole to tryptophan. This study examines the potential for functional variation in horizontally-acquired genes relative to their canonical counterparts, and identifies Blastocystis as a possible producer of tryptophan within the gut.     

Mutations in the N-terminal actin-binding domain of filamin C cause a distal myopathy

Linkage analysis of the dominant distal myopathy we previously identified in a large Australian family demonstrated one significant linkage region located on chromosome 7 and encompassing 18.6 Mbp and 151 genes. The strongest candidate gene was FLNC because filamin C, the encoded protein, is muscle-specific and associated with myofibrillar myopathy. Sequencing of FLNC cDNA identified a c.752T>C (p.Met251Thr) mutation in the N-terminal actin-binding domain (ABD); this mutation segregated with the disease and was absent in 200 controls. We identified an Italian family with the same phenotype and found a c.577G>A (p.Ala193Thr) filamin C ABD mutation that segregated with the disease. Filamin C ABD mutations have not been described, although filamin A and filamin B ABD mutations cause multiple musculoskeletal disorders. The distal myopathy phenotype and muscle pathology in the two families differ from myofibrillar myopathies caused by filamin C rod and dimerization domain mutations because of the distinct involvement of hand muscles and lack of pathological protein aggregation. Thus, like the position of FLNA and B mutations, the position of the FLNC mutation determines disease phenotype. The two filamin C ABD mutations increase actin-binding affinity in a manner similar to filamin A and filamin B ABD mutations. Cell-culture expression of the c.752T>C (p.Met251)Thr mutant filamin C ABD demonstrated reduced nuclear localization as did mutant filamin A and filamin B ABDs. Expression of both filamin C ABD mutants as full-length proteins induced increased aggregation of filamin. We conclude filamin C ABD mutations cause a recognizable distal myopathy, most likely through increased actin affinity, similar to the pathological mechanism of filamin A and filamin B ABD mutations.