Taxonomy, morphology and speciation of the Semicytherura henryhowei group (Crustacea, Ostracoda)

The genus Semicytherura belongs to the family Cytheruridae, and was distinguished from Cytherura on the basis of carapace features. Species of Semicytherura from Japan and adjacent seas can be divided into two groups. One is represented by Semicytherura miurensis Hanai, 1957, characterized by a thin, oval carapace covered with fine reticulation. The other is represented by Semicytherura henryhowei Hanai & Ikeya, 1977, characterized by a thick sub-rectangular carapace in lateral view. Semicytherura henryhowei, which is distributed from Hokkaido to Okinawa in Japan, has been regarded as having several morphotypes distinguishable on outline and reticulation of carapace. However, as a result of detailed observations on the copulatory organ, carapace outline and distributional pattern of pore systems, remarkable differences are shown to exist between the two most frequently occurring morphotypes. In order to recognize S. henryhowei sensu stricto, the carapace of the holotype was re-examined. Consequently, neither of the two morphotypes are considered to belong to S. henryhowei due to differences of carapace outline and distribution of pore systems. The two morphotypes are here regarded as independent taxa, described as new: S. kazahanan. sp. and S. sasameyukin. sp. The geographical distributions of the two new species overlap, but their micro-habitats differ from each other; the former lives on calcareous algae on rocky shores, the latter lives on silty sand bottom within the inner bay. A third new species, S. slipperi sp. nov., is also described. In view of their present geographical distributions and fossil records, the origin of this group of species would appear to be the Japanese islands or adjacent areas in and after the Miocene. This group then migrated to the Arctic Ocean and East Pacific Ocean during or before the middle Pliocene.     

Peptidomimetic modification improves cell permeation of bivalent farnesyltransferase inhibitors

Bivalent enzyme inhibitors, in which a surface binding module is linked to an active site binding module through a spacer, are a robust approach for site-selectively delivering a minimally-sized agent to a protein surface to regulate its functions, such as protein–protein interactions (PPIs). Previous research revealed that these agents effectively disrupt the interaction between farnesyltransferase (FTase) and the C-terminal region of K-Ras4B protein. However, the whole cell activity of these peptide-based agents is limited due to their low membrane permeability. In this study, we tested a peptidomimetic modification of these bivalent agents using a previously developed inhibitor, FTI-249, and evaluated their cell permeability and biological activity in cells. Confocal cell imaging using fluorescently-labeled agents showed that the peptidomimetic 3-BODIPY penetrated cells, while the peptide-based 1-BODIPY did not. Cell-based evaluation demonstrated that peptidomimetic 3 at a concentration of 100 μM inhibited HDJ-2 processing in cells, indicating that this peptidomimetic modification improves cell permeability, thus leading to enhanced whole cell activity of the bivalent compounds.     

Isolation and identification of a humanTRPV1 activating compound from soy sauce

Transient receptor potential vanilloid 1 (TRPV1) was identified as a receptor of capsaicin, which is a pungent ingredient in hot red peppers. Due to its relevance for nociception, a physiological and pharmacological study of TRPV1 has also been developed. Therefore, it is important to enrich scientific knowledge regarding the TRPV1 activating or inhibiting compounds. In this study, we fractionated soy sauce based on the human TRPV1 (hTRPV1) activity using column chromatography and purified 5-(9H-pyrido[3,4-b]indol-1-yl)-2-furanmethanol (perlolyrine) as an hTRPV1-activating compound. Additionally, perlolyrine activates the human transient receptor potential ankyrin 1 (hTRPA1). The EC₅₀ of hTRPV1 and hTRPA1 were 2.87 and 1.67 μmol L^?1, respectively. HPLC quantification of soy sauces showed that they contain 2.22–12.13 μmol L^?1 of perlolyrine. The sensory evaluation revealed that perlolyrine has taste modification effect. The results of this study, for the first time, suggest that perlolyrine induces the activation of hTRPV1 and hTRPA1.     

Identification of the mouse paternally expressed imprinted gene Zdbf2 on chromosome 1 and its imprinted human homolog ZDBF2 on chromosome 2

In mammals, both the maternal and paternal genomes are necessary for normal embryogenesis due to parent-specific epigenetic modification of the genome during gametogenesis, which leads to non-equivalent expression of imprinted genes from the maternal and paternal alleles. In this study, we identified a paternally expressed imprinted gene, Zdbf2, by microarray-based screening using parthenogenetic and normal embryos. Expression analyses showed that Zdbf2 was paternally expressed in various embryonic and adult tissues, except for the placenta and adult testis, which showed biallelic expression of the gene. We also identified a differentially methylated region (DMR) at 10 kb upstream of exon 1 of the Zdbf2 gene and this differential methylation was derived from the germline. Furthermore, we also identified that the human homolog (ZDBF2) of the mouse Zdbf2 gene showed paternal allele-specific expression in human lymphocytes but not in the human placenta. Thus, our findings defined mouse chromosome 1 and human chromosome 2 as the loci for imprinted genes.     

How is a giant sperm ejaculator formed? Development of the Zenker organ after the last moult in Pseudocandona marchica (Crustacea,Ostracoda, Candonidae)

‘Giant sperm’, in terms of exceptionally long spermatozoa, occur in various taxa in the animal kingdom, particularly in arthropods. In freshwater ostracods (Cypridoidea) reproducing with giant sperm, males are equipped with a pair of specialized ejaculators, or Zenker organs, located in the distal part of vas deferens.     

How ecology shapes exploitation: a framework to predict the behavioural response of human and animal foragers along exploration–exploitation trade‐offs

Understanding how humans and other animals behave in response to changes in their environments is vital for predicting population dynamics and the trajectory of coupled social‐ecological systems. Here, we present a novel framework for identifying emergent social behaviours in foragers (including humans engaged in fishing or hunting) in predator–prey contexts based on the exploration difficulty and exploitation potential of a renewable natural resource. A qualitative framework is introduced that predicts when foragers should behave territorially, search collectively, act independently or switch among these states. To validate it, we derived quantitative predictions from two models of different structure: a generic mathematical model, and a lattice‐based evolutionary model emphasising exploitation and exclusion costs. These models independently identified that the exploration difficulty and exploitation potential of the natural resource controls the social behaviour of resource exploiters. Our theoretical predictions were finally compared to a diverse set of empirical cases focusing on fisheries and aquatic organisms across a range of taxa, substantiating the framework's predictions. Understanding social behaviour for given social‐ecological characteristics has important implications, particularly for the design of governance structures and regulations to move exploited systems, such as fisheries, towards sustainability. Our framework provides concrete steps in this direction.     

Does genomic variation in a foundation species predict arthropod community structure in a riparian forest?

Understanding how genetic variation within a foundation species determines the structure of associated communities and ecosystem processes has been an emerging frontier in ecology. Previous studies in common gardens identified close links between intraspecific variation and multispecies community structure, and these findings are now being evaluated directly in the complex natural ecosystem. In this study, we examined to what extent genomic variation in a foundation tree species explains the structure of associated arthropod communities in the field, comparing with spatial, temporal and environmental factors. In a continuous mixed forest, arthropods were surveyed on 85 mature alders (Alnus hirsuta) in 2 years. Moreover, we estimated Nei's genetic distance among the alders based on 1,077 single nucleotide polymorphisms obtained from restricted‐site‐associated DNA sequencing of the alders’ genome. In both years, we detected significant correlations between genetic distance and dissimilarity of arthropod communities. A generalized dissimilarity modelling indicated that the genetic distance of alder populations was the most important predictor to explain the variance of arthropod communities. Among arthropod functional groups, carnivores were consistently correlated with genetic distance of the foundation species in both years. Furthermore, the extent of year‐to‐year changes in arthropod communities was more similar between more genetically closed alder populations. This study demonstrates that the genetic similarity rule would be primarily prominent in community assembly of plant‐associated arthropods under temporally and spatially variable environments in the field.