A global analysis of avian island diversity–area relationships in the Anthropocene

Research on island species–area relationships (ISAR) has expanded to incorporate functional (IFDAR) and phylogenetic (IPDAR) diversity. However, relative to the ISAR, we know little about IFDARs and IPDARs, and lack synthetic global analyses of variation in form of these three categories of island diversity–area relationship (IDAR). Here, we undertake the first comparative evaluation of IDARs at the global scale using 51 avian archipelagic data sets representing true and habitat islands. Using null models, we explore how richness-corrected functional and phylogenetic diversity scale with island area. We also provide the largest global assessment of the impacts of species introductions and extinctions on the IDAR. Results show that increasing richness with area is the primary driver of the (non-richness corrected) IPDAR and IFDAR for many data sets. However, for several archipelagos, richness-corrected functional and phylogenetic diversity changes linearly with island area, suggesting that the dominant community assembly processes shift along the island area gradient. We also find that archipelagos with the steepest ISARs exhibit the biggest differences in slope between IDARs, indicating increased functional and phylogenetic redundancy on larger islands in these archipelagos. In several cases introduced species seem to have ‘re-calibrated’ the IDARs such that they resemble the historic period prior to recent extinctions.     

Curdlan intake changes gut microbial composition,short-chain fatty acid production,and bile acid transformation in mice

Indigestible polysaccharides, such as dietary fibers, benefit the host by improving the intestinal environment. Short-chain fatty acids (SCFAs) produced by gut microbial fermentation from dietary fibers exert various physiological effects. The bacterial polysaccharide curdlan benefits the host intestinal environment, although its effect on energy metabolism and SCFA production remains unclear. Hence, this study aimed to elucidate the effect of curdlan intake on gut microbial profiles, SCFA production, and energy metabolism in a high-fat diet (HFD)-induced obese mouse model. Gut microbial composition of fecal samples from curdlan-supplemented HFD-fed mice indicated an elevated abundance of Bacteroidetes, whereas a reduced abundance of Firmicutes was noted at the phylum level compared with that in cellulose-supplemented HFD-fed mice. Moreover, curdlan supplementation resulted in an abundance of the family Bacteroidales S24-7 and Erysipelotrichaceae, and a reduction in Deferribacteres in the feces. Furthermore, curdlan supplementation elevated fecal SCFA levels, particularly butyrate. Although body weight and fat mass were not affected by curdlan supplementation in HFD-induced obese mice, HFD-induced hyperglycemia was significantly suppressed with an increase in plasma insulin and incretin GLP-1 levels. Curdlan supplementation elevated fecal bile acid and SCFA production, improved host metabolic functions by altering the gut microbial composition in mice.     

Experimental evidence that lignin-modifying enzymes are essential for degrading plant cell wall lignin by Pleurotus ostreatus using CRISPR/Cas9

Lignin-modifying enzymes (LMEs), which include laccases (Lacs), manganese peroxidases (MnPs), versatile peroxidases (VPs), and lignin peroxidases (LiPs), have been considered key factors in lignin degradation by white-rot fungi because they oxidize lignin model compounds and depolymerize synthetic lignin in vitro. However, it remains unclear whether these enzymes are essential/important in the actual degradation of natural lignin in plant cell walls. To address this long-standing issue, we examined the lignin-degrading abilities of multiple mnp/vp/lac mutants of Pleurotus ostreatus. One vp2/vp3/mnp3/mnp6 quadruple-gene mutant was generated from a monokaryotic wild-type strain PC9 using plasmid-based CRISPR/Cas9. Also, two vp2/vp3/mnp2/mnp3/mnp6, two vp2/vp3/mnp3/mnp6/lac2 quintuple-gene mutants, and two vp2/vp3/mnp2/mnp3/mnp6/lac2 sextuple-gene mutants were generated. The lignin-degrading abilities of the sextuple and vp2/vp3/mnp2/mnp3/mnp6 quintuple-gene mutants on the Beech wood sawdust medium reduced drastically, but not so much for those of the vp2/vp3/mnp3/mnp6/lac2 mutants and the quadruple mutant strain. The sextuple-gene mutants also barely degraded lignin in Japanese Cedar wood sawdust and milled rice straw. Thus, this study presented evidence that the LMEs, especially MnPs and VPs, play a crucial role in the degradation of natural lignin by P. ostreatus for the first time.     

Synchronous Activation of Cell Division by Light or Temperature Stimuli in the Dimorphic Yeast Schizosaccharomyces japonicus

Many fungi respond to light and regulate fungal development and behavior. A blue light-activated complex has been identified in Neurospora crassa as the product of the wc-1 and wc-2 genes. Orthologs of WC-1 and WC-2 have hitherto been found only in filamentous fungi and not in yeast, with the exception of the basidiomycete pathogenic yeast Cryptococcus. Here, we report that the fission yeast Schizosaccharomyces japonicus responds to blue light depending on Wcs1 and Wcs2, orthologs of components of the WC complex. Surprisingly, those of ascomycete S. japonicus are more closely related to those of the basidiomycete. S. japonicus reversibly changes from yeast to hyphae in response to environmental stresses. After incubation at 30°C, a colony of yeast was formed, and then hyphal cells extended from the periphery of the colony. When light cycles were applied, distinct dark- and bright-colored hyphal cell stripes were formed because the growing hyphal cells had synchronously activated cytokinesis. In addition, temperature cycles of 30°C for 12 h and 35°C for 12 h or of 25°C for 12 h and 30°C for 12 h during incubation in the dark induced a response in the hyphal cells similar to that of light. The stripe formation of the temperature cycles was independent of the wcs genes. Both light and temperature, which are daily external cues, have the same effect on growing hyphal cells. A dual sensing mechanism of external cues allows organisms to adapt to daily changes of environmental alteration.     

New organic reference materials for carbon- and nitrogen-stable isotope ratio measurements provided by Center for Ecological Research,Kyoto University,and Institute of Biogeosciences,Japan Agency for Marine-Earth Science and Technology

We determined both carbon and nitrogen isotope ratios of ten organic reference materials (CERKU-01 to CERKU-10) in the Center for Ecological Research (CER), Kyoto University, and three organic reference materials (BG-A, BG-P, and BG-T) in the Institute of Biogeosciences (BioGeos), Japan Agency for Marine-Earth Science and Technology (JAMSTEC), using an internationally recommended calibration method of two-point anchoring. The reference materials cover δ¹³C_VPDB range of −34.92 to −9.45‰ and δ¹⁵N_Air range of −5.22 to 22.71‰ and can be used to measure isotope ratios of naturally occurring substances.     

Phylogeny and systematics of Sphaeriusidae (Coleoptera: Myxophaga): minute living fossils with underestimated past and present-day diversity

Sphaeriusidae (Coleoptera: Myxophaga) is a group of shiny, blackish and hemispherical riparian beetles, known for their miniaturized bodies. They are worldwide in distribution, but very limited information is available about taxonomic and morphological diversity, and natural and evolutionary history. The aim of this study is to help fill in these gaps. We examined the external morphology of modern representatives using scanning electron microscopy (SEM), and reconstructed the phylogeny of the family using five DNA markers (cytochrome oxidase I, 18S rRNA, 28S rRNA, CAD and wingless). Our results suggest a larger morphological diversity than previously expected, corresponding to the deep genetic divergences of principal lineages. We also examined two inclusions in 99-million-year-old Burmese amber. The integration of all evidence allows us to recognize three genera: the extinct genus †Burmasporum Kirejtshuk, the newly defined genus Bezesporum gen.nov. preserved in Burmese amber (B. burmiticum sp.nov. ) and present in the modern fauna of Southeast Asia, and the genus Sphaerius Waltl with a world-wide distribution. Sphaerius species are morphologically highly uniform, with the exception of species from Australia and South Africa, which share some characteristics with Bezesporum gen.nov. despite being resolved as deeply nested lineages of Sphaerius by DNA data. The presence of Bezesporum gen.nov. in Burmese amber and in recent fauna indicates that Sphaeriusidae largely maintained their specific morphology and specialized riparian lifestyle for at least 100 million years. Therefore, they can be considered an exceptionally conserved group, with a minimum of evolutionary changes over a long period. Our study also demonstrates that the species numbers and fine-scale morphological diversity of Sphaeriusidae are larger than expected in both the past and present-day faunas. Both were apparently underestimated due to the minute body size and cryptic habits of these beetles.     

Fermented product of rice with Lactobacillus kefiranofaciens induces anti-aging effects and heat stress tolerance in nematodes via DAF-16

ABSTRACT

Rice kefiran is superior in functionality, has high concentration of mucilaginous polysaccharide, and low lipid content, compared to conventional kefiran. However, reports on its physiological functionality, especially studies on life expectancy and aging, in model organisms are rare. In this study, nematodes were used as model organisms that were fed rice kefiran, along with Escherichia coli OP50, as a result of which, the lifespan of nematodes was extended and age-related retardation of mobility was suppressed. It also increased the heat stress resistance in nematodes. Experiments using daf-16 deletion mutant revealed that rice kefiran functions via DAF-16. Thus, this study revealed the longevity, anti-aging and heat stress tolerance effects of rice kefiran in nematodes.     

Mammal assemblages recorded by camera traps inside and outside the evacuation zone of the Fukushima Daiichi Nuclear Power Plant accident

In 2011, the Fukushima Daiichi Power Plant accident resulted in the evacuation of about 81,000 people from the evacuation zone, which suffered from high levels of radioactive contamination. Large-scale and long-term land abandonment can cause changes in species assemblages. Despite the extensive global attention this incident received, open and spatially-explicit datasets of mammal fauna from Fukushima remain quite limited. We established a continuous monitoring protocol using camera traps for mammals both inside and outside the evacuation zone; this paper presents our first dataset. These data represent the monitoring results from 45 camera traps from May 2014 to October 2014, including the location and actuation time of each camera, and the list of video records. After the publication of this initial data paper, we intend to continue monitoring until 2023 and the dataset will be hereafter updated with new observations.