A modified cornish pasty method for ex ovo culture of the chick embryo development

Chick embryos grown in ex ovo culture by the modified Cornish pasty method reported in Nagai, Lin and Sheng in this issue.     

Can an acoustic observatory contribute to the conservation of threatened species?

Observatories are designed to collect data for a range of uses. The Australian Acoustic Observatory (A2O) was established to collect environmental sound, including audible species calls, from 344 recorders at 86 sites around Australia. We examine the potential of the A2O to monitor near threatened, threatened, endangered and critically endangered species, based on their vocal behaviour, geographic distributions in relation to the sites of the A2O and on some knowledge of habitat use. Using IUCN and EPBC lists of threatened and endangered species, we extracted species that vocalized in the audible range, and using conservative estimates of their geographic ranges, determined whether there was a possibility of hearing them at these sites. We found that it may be possible to detect up to 171 threatened species at sites established for the A2O, and that individual sites have the potential to detect up to 40 threatened species. All 86 sites occurred in locations where threatened species could possibly be detected, and the list of detectable species included birds, amphibians, and mammals. We have incidentally detected one mammal and four bird species in the data during other work. Threatening processes to which potentially detectable species were exposed included all but two IUCN threat categories. We concluded that with applications of technology to search the audio data from the A2O, it could serve as an important tool for monitoring threatened species.     

Efficiency Boost in All-Small-Molecule Organic Solar Cells: Insights from the Re-Ordering Kinetics

Achieving high-performance in all-small-molecule organic solar cells (ASM-OSCs) significantly relies on precise nanoscale phase separation through domain size manipulation in the active layer. Nonetheless, for ASM-OSC systems, forging a clear connection between the tuning of domain size and the intricacies of phase separation proves to be a formidable challenge. This study investigates the intricate interplay between domain size adjustment and the creation of optimal phase separation morphology, crucial for ASM-OSCs’ performance. It is demonstrated that exceptional phase separation in ASM-OSCs’ active layer is achieved by meticulously controlling the continuity and uniformity of domains via re-packing process. A series of halogen-substituted solvents (Fluorobenzene, Chlorobenzene, Bromobenzene, and Iodobenzene) is adopted to tune the re-packing kinetics, the ASM-OSCs treated with CB exhibited an impressive 16.2% power conversion efficiency (PCE). The PCE enhancement can be attributed to the gradual crystallization process, promoting a smoothly interconnected and uniformly distributed domain size. This, in turn, leads to a favorable phase separation morphology, enhanced charge transfer, extended carrier lifetime, and consequently, reduced recombination of free charges. The findings emphasize the pivotal role of re-packing kinetics in achieving optimal phase separation in ASM-OSCs, offering valuable insights for designing high-performance ASM-OSCs fabrication strategies.     

A New Statistic to Evaluate Imputation Reliability

Background

As the amount of data from genome wide association studies grows dramatically, many interesting scientific questions require imputation to combine or expand datasets. However, there are two situations for which imputation has been problematic: (1) polymorphisms with low minor allele frequency (MAF), and (2) datasets where subjects are genotyped on different platforms. Traditional measures of imputation cannot effectively address these problems.

Methodology/Principal Findings

We introduce a new statistic, the imputation quality score (IQS). In order to differentiate between well-imputed and poorly-imputed single nucleotide polymorphisms (SNPs), IQS adjusts the concordance between imputed and genotyped SNPs for chance. We first evaluated IQS in relation to minor allele frequency. Using a sample of subjects genotyped on the Illumina 1 M array, we extracted those SNPs that were also on the Illumina 550 K array and imputed them to the full set of the 1 M SNPs. As expected, the average IQS value drops dramatically with a decrease in minor allele frequency, indicating that IQS appropriately adjusts for minor allele frequency. We then evaluated whether IQS can filter poorly-imputed SNPs in situations where cases and controls are genotyped on different platforms. Randomly dividing the data into “cases” and “controls”, we extracted the Illumina 550 K SNPs from the cases and imputed the remaining Illumina 1 M SNPs. The initial Q-Q plot for the test of association between cases and controls was grossly distorted (λ = 1.15) and had 4016 false positives, reflecting imputation error. After filtering out SNPs with IQS<0.9, the Q-Q plot was acceptable and there were no longer false positives. We then evaluated the robustness of IQS computed independently on the two halves of the data. In both European Americans and African Americans the correlation was >0.99 demonstrating that a database of IQS values from common imputations could be used as an effective filter to combine data genotyped on different platforms.

Conclusions/Significance

IQS effectively differentiates well-imputed and poorly-imputed SNPs. It is particularly useful for SNPs with low minor allele frequency and when datasets are genotyped on different platforms.     

Production of cellulolytic enzymes from theXylaria andHypoxylon species of xylariaceae

Eighteen strains of xylariaceous fungi have been screened for higher activities of cellulolytic enzymes,Trichoderma reesei QM 9414 was also examined for comparison. Strains ofXylaria anisopleura andX. regalis had higher endocellulase (CMCase) and exocellulase (Avicelase) activities after 2 weeks' incubation.Hypoxylon stygium produced the highest activity of -glucosidase 3 days after inoculation. The optimum pH for these cellulolytic enzymes was approx. 5.0 and the optimum temperatures ranged from 37 to 50°C. A mixed culture process usingT. reesei QM 9414 andH. stygium was developed to obtain enhanced synthesis of cellulase. -Glucosidase activities in the mixed culture increased within 48h whenH. stygium was introduced after 24h.     

The role of pleiotrophin and β-catenin in fetal lung development

Mammalian lung development is a complex biological process, which is temporally and spatially regulated by growth factors, hormones, and extracellular matrix proteins. Abnormal changes of these molecules often lead to impaired lung development, and thus pulmonary diseases. Epithelial-mesenchymal interactions are crucial for fetal lung development. This paper reviews two interconnected pathways, pleiotrophin and Wnt/β-catenin, which are involved in fibroblast and epithelial cell communication during fetal lung development.     

Metarhizium robertsii Produces an Extracellular Invertase (MrINV) That Plays a Pivotal Role in Rhizospheric Interactions and Root Colonization

As well as killing pest insects, the rhizosphere competent insect-pathogenic fungus Metarhizium robertsii also boosts plant growth by providing nitrogenous nutrients and increasing resistance to plant pathogens. Plant roots secrete abundant nutrients but little is known about their utilization by Metarhizium spp. and the mechanistic basis of Metarhizium-plant associations. We report here that M. robertsii produces an extracellular invertase (MrInv) on plant roots. Deletion of MrInv (⊿MrInv) reduced M. robertsii growth on sucrose and rhizospheric exudates but increased colonization of Panicum virgatum and Arabidopsis thaliana roots. This could be accounted for by a reduction in carbon catabolite repression in ⊿MrInv increasing production of plant cell wall-degrading depolymerases. A non-rhizosphere competent scarab beetle specialist Metarhizium majus lacks invertase which suggests that rhizospheric competence may be related to the sugar metabolism of different Metarhizium species.     

Extracellular expression, purification, and characterization of a winter flounder antifreeze polypeptide from Escherichia coli

HPLC6 is the major component of liver-type antifreeze polypeptides (AFPs) from the winter flounder, Pleuronectes americanus. To facilitate mutagenesis studies of this protein, a gene encoding the 37-amino acid mature polypeptide was chemically synthesized and cloned into the Tac cassette immediately after the bacterial ompA leader sequence for direct excretion of the AFP into the culture medium. Escherichia coli transformant with the construct placIQpar8AF was cultured in M9 medium. The recombinant AFP (rAFP) was detected by a competitive enzyme-linked immunosorbent assay (ELISA). After IPTG induction, a biologically active rAFP was expressed. The majority of the rAFP was excreted into the culture medium with only trace amounts trapped in the periplasmic space and cytoplasm. After 18 h of induction, the accumulated rAFP in the culture medium amounted to about 16 mg/L. The excreted AFP was purified from the culture medium by a single-step reverse-phase HPLC. Mass spectrometric and amino acid composition analyses confirmed the identity of the purified product. The rAFP, which lacked amidation at the C-terminal, was about 70% active when compared to the amidated wild-type protein, thus confirming the importance of C-terminal cap structure in protein stability and function.