Are extra‐pair males different from cuckolded males? A case study and a meta‐analytic examination

Traditional models for female extra‐pair matings assume that females benefit indirectly from extra‐pair mating behaviour. Under these so‐called adaptive models, extra‐pair males are hypothesized to have more compatible genotypes, larger body size, exaggerated ornaments or to be older than cuckolded males. Alternatively, (‘nonadaptive’) models that consider female extra‐pair matings to be a by‐product posit that female extra‐pair mating can be maintained even if there is no benefit to females. This could happen if, for example, males gained fitness benefits from extra‐pair mating, while female and male extra‐pair mating behaviours were genetically correlated. Extra‐pair males are also expected to be older and larger if this improves their ability to convince or coerce females to mate. We investigated whether a female's extra‐pair mates differed from her cuckolded mate in both genetic and phenotypic traits by analysing data from an insular house sparrow population. We found that extra‐pair males were older than cuckolded males, consistent with both models. However, in contrast to the expectations from from adaptive models, extra‐pair and cuckolded males were of similar genetic relatedness, and hence expected compatibility, with the female, and had comparable body size and secondary sexual traits. We also updated previous meta‐analyses examining differences between extra‐pair and cuckolded males. The meta‐analytic results matched results from our house sparrow case study. Although we cannot completely exclude indirect benefits for females, nonadaptive models may better explain female extra‐pair matings. These neglected alternative models deserve more research attention, and this should improve our understanding of the evolution of mating systems.     

FERONIA receptor kinase interacts with S‐adenosylmethionine synthetase and suppresses S‐adenosylmethionine production and ethylene biosynthesis in Arabidopsis

Environmental inputs such as stress can modulate plant cell metabolism, but the detailed mechanism remains unclear. We report here that FERONIA (FER), a plasma membrane receptor‐like kinase, may negatively regulate the S‐adenosylmethionine (SAM) synthesis by interacting with two S‐adenosylmethionine synthases (SAM1 and SAM2). SAM participates in ethylene, nicotianamine and polyamine biosynthetic pathways and provides the methyl group for protein and DNA methylation reactions. The Arabidopsis fer mutants contained a higher level of SAM and ethylene in plant tissues and displayed a dwarf phenotype. Such phenotype in the fer mutants was mimicked by over‐expressing the S‐adenosylmethionine synthetase in transgenic plants, whereas sam1/2 double mutant showed an opposite phenotype. We propose that FER receptor kinase, in response to environmental stress and plant hormones such as auxin and BR, interacts with SAM synthases and down‐regulates ethylene biosynthesis.     

Highly sensitive and selective uric acid biosensor based on a three-dimensional graphene foam/indium tin oxide glass electrode

A three-dimensional (3D) continuous and interconnected network graphene foam (GF) was synthesized by chemical vapor deposition using nickel foam as a template. The morphologies of the GF were observed by scanning electron microscopy. X-ray diffraction and Raman spectroscopy were used to investigate the structure of GF. The graphene with few layers and defect free was closely coated on the backbone of the 3D nickel foam. After etching nickel, the GF was transferred onto indium tin oxide (ITO) glass, which acted as an electrode to detect uric acid using cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The GF/ITO electrode showed a high sensitivity for the detection of uric acid: approximately 9.44 mA mM⁻¹ in the range of 25 nM–0.1 μM and 1.85 mA mM⁻¹ in the range of 0.1–60 μM. The limit of detection of GF/ITO electrode for uric acid is 3 nM. The GF/ITO electrode also showed a high selectivity for the detection of uric acid in the presence of ascorbic acid. This electrode will have a wide range of potential application prospects in electrochemical detection.     

Effects of calpain inhibitor on the apoptosis of hepatic stellate cells induced by calcium ionophore A23187

We previously showed that changes in calcium concentrations were related to cell apoptosis in vitro. The endoplasmic reticulum (ER) is the main component of calcium storage and signal transduction, and disrupting the balance of intracellular Ca²⁺ can cause endoplasmic reticulum stress (ERS). In this process, the ER releases stored Ca ²⁺ into the cytoplasm and activates calpain-2. To further investigate the effect of calpain in hepatic stellate cells (HSCs), in the current study, we examine the effect of N-acetyl-leu-leu-norleucinal (ALLN) on apoptosis resulting from calcium ionophore A23187–induced ERS. Our findings indicate that calpain inhibition reduces calcium ionophore A23187–induced apoptosis of HSCs and decreases the expression of ER stress proteins that may be related to the calpain/caspase signaling pathway.     

Widespread occurrence and unexpected diversity of red-shifted chlorophyll producing cyanobacteria in humid subtropical forest ecosystems

Discovery of red-shifted chlorophyll d and f in cyanobacteria has opened up new avenues to estimate global carbon fixation driven by far-red light. Shaded habitats in humid subtropical forest ecosystems contain an increased proportion of far-red light components relative to residual white light. After an extensive survey of shaded ecosystems within subtropical forests, wide occurrence of red-shifted chlorophyll-producing cyanobacteria was demonstrated by isolated Chl f-producing and Chl d-containing cyanobacteria. Chl f-producing cyanobacteria were classified into the genera of Aphanocapsa and Chroococcidiopsis and two undescribed genera within Leptolyngbyaceae. Newly isolated Chl d-containing Acaryochloris sp. CCNUM4 showed the closest phylogenetic relationship with Acaryochloris species isolated from marine environments. Acaryochloris sp. CCNUM4 produced Chl d as major photopigment, and Chl f-producing cyanobacteria use Chl a under white light conditions but Chl a + f under far-red light conditions. Their habitats are widely distributed in subtropical forest ecosystems and varied from mosses on limestone to macrophyte and freshwater in the streams and ponds. This study presents a significant advance in the knowledge of distribution and diversity of red-shifted chlorophyll-producing cyanobacteria in terrestrial ecosystems. The results suggest that Chl f-producing and Chl d-containing cyanobacteria might be important primary producers in far-red light dominant niches worldwide.