Two new species in the family Axinellidae (Porifera,Demospongiae) from British Columbia and adjacent waters

Two new species of Demospongiae are described for British Columbia and adjacent waters in the family Axinellidae, Auletta krautteri sp. n. and Dragmacidon kishinensis sp. n. They represent range extensions for both of these genera. Both are fairly commonly encountered, Auletta krautteri below diving depths (87 to at least 300 m) and Dragmacidon kishinensis in shallow water (intertidal to 30 m). We propose an amended genus diagnosis for Auletta to account for the variability among species in principal spicules that form the ascending tracts to be either oxeas, styles or strongyles rather than just oxeas.     

Plasma carbonyls do not correlate with lung function or computed tomography measures of lung density in older smokers

Abstract

Oxidative stress and inflammation are hallmarks of chronic obstructive pulmonary disease (COPD). A critical byproduct of oxidative damage is the introduction of carbonyl groups into amino acid residues. We hypothesize that plasma carbonyl content is inversely correlated with lung function and computed tomography (CT) measures of lung density among smokers and is elevated in COPD. Carbonyl was measured in plasma of participants aged 60 years and older by ELISA. Generalized linear and additive models were used to adjust for potential confounders. Among 541 participants (52% male, mean age 67 years, 41% current smokers), mean plasma carbonyl content was 17.9±2.9 nmol ml^?1 and mean forced expiratory volume in one second (FEV₁) was 80.7±20.9% of predicted. Plasma carbonyl content was inversely associated with FEV₁, but this relationship was largely explained by age. Multivariate analyses ruled out clinically meaningful associations of plasma carbonyl content with FEV₁, FEV₁/FVC (forced vital capacity) ratio, severity of airflow obstruction, and CT lung density. Plasma carbonyl content is a poor biomarker of oxidative stress in COPD and emphysema.     

It doesn’t always pay to be fit: success landscapes

Journal of Biological Physics - Landscapes play an important role in many areas of biology, in which biological lives are deeply entangled. Here we discuss a form of landscape in evolutionary...     

CENP-A overexpression promotes aneuploidy with karyotypic heterogeneity

Chromosomal instability (CIN) is a hallmark of many cancers. Restricting the localization of centromeric histone H3 variant CENP-A to centromeres prevents CIN. CENP-A overexpression (OE) and mislocalization have been observed in cancers and correlate with poor prognosis; however, the molecular consequences of CENP-A OE on CIN and aneuploidy have not been defined. Here, we show that CENP-A OE leads to its mislocalization and CIN with lagging chromosomes and micronuclei in pseudodiploid DLD1 cells and xenograft mouse model. CIN is due to reduced localization of proteins to the kinetochore, resulting in defects in kinetochore integrity and unstable kinetochore–microtubule attachments. CENP-A OE contributes to reduced expression of cell adhesion genes and higher invasion of DLD1 cells. We show that CENP-A OE contributes to aneuploidy with karyotypic heterogeneity in human cells and xenograft mouse model. In summary, our results provide a molecular link between CENP-A OE and aneuploidy, and suggest that karyotypic heterogeneity may contribute to the aggressive phenotype of CENP-A–overexpressing cancers.     

Regulating the expression of gene drives is key to increasing their invasive potential and the mitigation of resistance

Homing-based gene drives use a germline source of nuclease to copy themselves at specific target sites in a genome and bias their inheritance. Such gene drives can be designed to spread and deliberately suppress populations of malaria mosquitoes by impairing female fertility. However, strong unintended fitness costs of the drive and a propensity to generate resistant mutations can limit a gene drive’s potential to spread.Alternative germline regulatory sequences in the drive element confer improved fecundity of carrier individuals and reduced propensity for target site resistance. This is explained by reduced rates of end-joining repair of DNA breaks from parentally deposited nuclease in the embryo, which can produce heritable mutations that reduce gene drive penetrance.We tracked the generation and selection of resistant mutations over the course of a gene drive invasion of a population. Improved gene drives show faster invasion dynamics, increased suppressive effect and later onset of target site resistance. Our results show that regulation of nuclease expression is as important as the choice of target site when developing a robust homing-based gene drive for population suppression.     

Programmatic change: lung disease research in the era of induced pluripotency

Human lung research has made remarkable progress over the last century largely through the use of animal models of disease. The challenge for the future is to translate these findings into human disease and bring about meaningful disease modification or even cure. The ability to generate transformative therapies in the future will require human tissue, currently scarce under the best of circumstances. Unfortunately, patient-derived somatic cells are often poorly characterized and have a limited life span in culture. Moreover, these cells are frequently obtained from patients with end-stage disease exposed to multiple drug therapies, leaving researchers with questions about whether their findings recapitulate disease-initiating processes or are simply the result of pharmacological intervention or subsequent host responses. The goal of studying early disease in multiple cell and tissue types has driven interest in the use of induced pluripotent stem cells (iPSCs) to model lung disease. These cells provide an alternative model for relevant lung research and hold promise in particular for studying the initiation of disease processes in genetic conditions such as heritable pulmonary arterial hypertension as well as other lung diseases. In this Perspective, we focus on potential iPSC use in pulmonary vascular disease research as a model for iPSC use in many types of advanced lung disease.     

Gaussian curvature analysis allows for automatic block placement in multi-block hexahedral meshing

Musculoskeletal finite element analysis (FEA) has been essential to research in orthopaedic biomechanics. The generation of a volumetric mesh is often the most challenging step in a FEA. Hexahedral meshing tools that are based on a multi-block approach rely on the manual placement of building blocks for their mesh generation scheme. We hypothesise that Gaussian curvature analysis could be used to automatically develop a building block structure for multi-block hexahedral mesh generation. The Automated Building Block Algorithm incorporates principles from differential geometry, combinatorics, statistical analysis and computer science to automatically generate a building block structure to represent a given surface without prior information. We have applied this algorithm to 29 bones of varying geometries and successfully generated a usable mesh in all cases. This work represents a significant advancement in automating the definition of building blocks.     

Seed viability in declining populations of Caladenia rigida (Orchidaceae): are small populations doomed?

Despite comparatively good rates of pollination and seed production, some populations of the endangered terrestrial orchid Caladenia rigida continue to decline. To determine whether seed quality may be limiting reproductive potential, we assessed seed viability among declining populations of C.?rigida (in the southern part of its distribution) and among populations that are regarded as stable (in the northern part of its distribution). We also compared differences in seed viability to plant traits, population size and habitat characteristics (soil properties, canopy cover, presence of proximate vegetation). Seed capsules from southern populations were significantly smaller, with only 9% of seeds being viable, compared to 36% in capsules from northern populations. Soil phosphorus concentrations differed between regions, but other habitat characteristics did not correlate with seed viability. Using calculations based on seedling recruitment data from other Caladenia species, we predict that seed output is insufficient to ensure the long-term persistence of the smallest C.?rigida populations.     

Integrating computational and mixture-based screening of combinatorial libraries

Mixture-based synthetic combinatorial library (MB-SCL) screening is a well-established experimental approach for rapidly retrieving structure–activity relationships (SAR) and identifying hits. Virtual screening is also a powerful approach that is increasingly being used in drug discovery programs and has a growing number of successful applications. However, limited efforts have been made to integrate both techniques. To this end, we combined experimental data from a MB-SCL of bicyclic guanidines screened against the κ-opioid receptor and molecular similarity methods. The activity data and similarity analyses were integrated in a biometric analysis–similarity map. Such a map allows the molecules to be categorized as actives, activity cliffs, low similarity to the reference compounds, or missed hits. A compound with IC₅₀ = 309 nM was found in the “missed hits” region, showing that active compounds can be retrieved from a MS-SCL via computational approaches. The strategy presented in this work is general and is envisioned as a general-purpose approach that can be applied to other MB-SCLs.