Does land-use change affect biodiversity dynamics at a macroecological scale? A case study of birds over the past 20 years in Japan

Because the effects of land-use change on biodiversity have primarily been examined at or below the regional scale, it remains unclear whether such effects scale up to the macroecological scale (i.e. nationwide or continental scale). In Japan, forests have become more mature since the cessation of most forestry efforts in the 1970s. At a nationwide scale, this forest maturation may lead to reductions in the abundance of species that depend on early successional forests (early successional species) and increases in the abundance of species that depend on mature forests (mature forest species). Japan has met its high demand for wood through imports from South-east Asia, resulting in deforestation there. Therefore, the abundance of mature forest species that migrate long distances to overwinter in South-east Asia may decrease. We examined changes in the range sizes of birds in Japan over the past 20 years using the living planet index (LPI). The LPI indicated that the range sizes of early successional species decreased. For mature forest species, the range sizes of long-distance migrants decreased, whereas those of short-distance migrants and residents increased. Our predictions were generally supported. Our results indicate that the effects of land-use change extend to the macroecological scale and that such changes in one country can affect the biodiversity dynamics in other countries. Forest maturation in Japan and concomitant deforestation in South-east Asia have been caused by internationally coupled socioeconomic processes. Therefore, biodiversity conservation at the macroecological scale must consider the role of land use, and such efforts will require both international and socioeconomic perspectives.     

Application of a 3,3-diphenylpentane skeleton as a multi-template for creation of HMG-CoA reductase inhibitors

Based on our hypothesis that the 3,3-diphenylpentane (DPP) skeleton is useful as a multi-template for creation of various biologically active compounds and acts as a steroid skeleton substitute, we designed and synthesized novel HMG-CoA reductase inhibitors with a DPP skeleton. Among them, sodium (E,3R,5S)-7-(2-(4-fluorophenyl)-4-(3-phenylpentan-3-yl)phenyl)-3,5-dihydroxy-hept-6-enoate showed potent HMG-CoA reductase-inhibitory activity comparable with that of clinically useful mevastatin.     

Modified molecular interactions of the pheophytin and plastoquinone electron acceptors in photosystem II of chlorophyll d-containing Acaryochloris marina as revealed by FTIR spectroscopy

Photosynthesis Research - Acaryochloris marina is a unique cyanobacterium that contains chlorophyll (Chl) d as a major pigment. Because Chl d has smaller excitation energy than Chl a used in...     

Myosin IIA is required for neurite outgrowth inhibition produced by repulsive guidance molecule

Although myelin-associated neurite outgrowth inhibitors express their effects through RhoA/Rho-kinase, the downstream targets of Rho-kinase remain unknown. We examined the involvement of myosin II, which is one of the downstream targets of Rho-kinase, by using blebbistatin – a specific myosin II inhibitor – and small interfering RNA targeting two myosin II isoforms, namely, MIIA and MIIB. We found that neurite outgrowth inhibition by repulsive guidance molecule (RGMa) was mediated via myosin II, particularly MIIA, in cerebellar granule neurons. RGMa induced myosin light chain (MLC) phosphorylation by a Rho-kinase-dependent mechanism. After spinal cord injury in rats, phosphorylated MLC in axons around the lesion site was up-regulated, and this effect depends on Rho-kinase activity. Further, RGMa-induced F-actin reduction in growth cones and growth cone collapse were mediated by MIIA. We conclude that Rho-kinase-dependent activation of MIIA via MLC phosphorylation induces F-actin reduction and growth cone collapse and the subsequent neurite retraction/outgrowth inhibition triggered by RGMa.     

Evidence for the presence of membrane-bound forms of acid protease in Aspergillus oryzae.

While approximately 85% of the cell-bound acid protease of $\text{Aspergillus oryzae}$ were recovered in the soluble fraction upon disruption of cells, the rest of the enzyme was found to be present tightly associated with the membranes. Two forms of membrane-bound enzyme, which were solubilized with Triton X-100, were similar to the external acid protease found in culture medium in that they had an optimum pH at 3.2, activated trypsinogen at pH 3 and lost their activity upon treatment with 5.1 mM sodium dodecylsulfonate. However, they differed in their hydrophobic properties (i.e. aggregation in the absence of Triton X-100 and activation by the detergent) from both the cell-bound, soluble form and the one excreted into culture medium.     

Phylogenetic Position and In Situ Identification of Ectosymbiotic Spirochetes on Protists in the Termite Gut

Phylogenetic relationships, diversity, and in situ identification of spirochetes in the gut of the termite Neotermes koshunensis were examined without cultivation, with an emphasis on ectosymbionts attached to flagellated protists. Spirochetes in the gut microbial community investigated so far are related to the genus Treponema and divided into two phylogenetic clusters. In situ hybridizations with a 16S rRNA-targeting consensus oligonucleotide probe for one cluster (known as termite Treponema cluster I) detected both the ectosymbiotic spirochetes on gut protists and the free-swimming spirochetes in the gut fluid of N. koshunensis. The probe for the other cluster (cluster II), which has been identified as ectosymbionts on gut protists of two other termite species, Reticulitermes speratus and Hodotermopsis sjoestedti, failed to detect any spirochete population. The absence of cluster II spirochetes in N. koshunensis was confirmed by intensive 16S ribosomal DNA (rDNA) clone analysis, in which remarkably diverse spirochetes of 45 phylotypes were identified, almost all belonging to cluster I. Ectosymbiotic spirochetes of the three gut protist species Devescovina sp., Stephanonympha sp., and Oxymonas sp. in N. koshunensis were identified by their 16S rDNA and by in situ hybridizations using specific probes. The probes specific for these ectosymbionts did not receive a signal from the free-swimming spirochetes. The ectosymbionts were dispersed in cluster I of the phylogeny, and they formed distinct phylogenetic lineages, suggesting multiple origins of the spirochete attachment. Each single protist cell harbored multiple spirochete species, and some of the spirochetes were common among protist species. The results indicate complex relationships of the ectosymbiotic spirochetes with the gut protists.     

Effects of E. coli chaperones on the solubility of human receptors in an in vitro expression system

The implementation of efficient technologies for the production of recombinant mammalian membrane receptors is an outstanding challenge in understanding receptor-ligand actions and the development of therapeutic antibodies. In order to improve the solubility of recombinant extracellular domains of human membrane receptors expressed in Escherichia coli, proteins were synthesized by an E. coli in vitro translation system supplemented with bacterial molecular chaperones, such as GroEL-GroES (GroEL/ES), Trigger factor (TF), a DnaK-DnaJ-GrpE chaperone system (DnaKJE), and/or a heat shock protein Hsp100, ClpB. The following three proteins that are prone to aggregation were examined: the extracellular domain (ECD) or the second immunoglobulin-like domain (IgII) of the human neurotrophin receptor TrkC (TrkC-ECD and TrkC-IgII), and the C-type lectin carbohydrate recognition domain of the human asialoglycoprotein receptor (ASGPR HI CRD). The cooperative chaperone system including GroEL/ES, DnaKJE and ClpB had a marked effect on the solubility of TrkC-ECD and TrkC-IgII, and the GroEL/ES-DnaKJE-TF chaperone system was more effective for TrkC-IgII. The GroEL/ES-DnaKJE-TF chaperone network increased the yield of soluble ASGPR HI CRD. The present findings demonstrate that E. coli molecular chaperones are useful in improving the yield of soluble recombinant extracellular domains of human membrane receptors in an E. coli expression system.