Frequency-dependent herbivory by a leaf beetle,Phaedon brassicae,on hairy and glabrous plants of Arabidopsis halleri subsp. gemmifera

Frequency-dependent prey choice by natural enemies may influence the coexistence of multiple prey types, but little is known about whether frequency-dependent foraging choice occurs in herbivory on plants showing resistance polymorphism within a single population. Here we examined frequency-dependent foraging by a crucifer-feeding leaf beetle, Phaedon brassicae, on trichome-producing (hairy) and trichomeless (glabrous) plants coexisting within a natural population of the perennial herb Arabidopsis halleri subsp. gemmifera. Larvae of P. brassicae fed on hairy leaves showed slower growth than those fed on glabrous leaves. Although adult beetles consumed similar amounts of leaves when they were fed either hairy or glabrous leaves in no-choice conditions, our choice experiment showed that adult beetles fed at less than the proportionally expected level on hairy leaves compared to glabrous leaves when the hairy leaves were less or equally abundant. Both types of leaves were consumed at the proportionally expected levels when the hairy leaves were more abundant than the glabrous leaves. In a natural population, the leaf damage on the hairy plants was negatively correlated with the local proportion of the glabrous plants in a 1-m diameter patch across 2 years, while correlations between the leaf damage on the glabrous plants and their proportion differed between the 2 years. Additionally, we found five glucosinolates in leaves of A. halleri, but their accumulation did not differ between hairy and glabrous plants. Our experimental results indicate that hairy plants incur less herbivory by P. brassicae when glabrous plants are abundant. The field pattern provides evidence suggestive of frequency-dependent herbivory acting on hairy plants. The present study highlights one of the putative mechanisms of maintaining plant resistance polymorphism.     

Editor's choice: Dissection of the Octoploid Strawberry Genome by Deep Sequencing of the Genomes of Fragaria Species

Cultivated strawberry (Fragaria x ananassa) is octoploid and shows allogamous behaviour. The present study aims at dissecting this octoploid genome through comparison with its wild relatives, F. iinumae, F. nipponica, F. nubicola, and F. orientalis by de novo whole-genome sequencing on an Illumina and Roche 454 platforms. The total length of the assembled Illumina genome sequences obtained was 698 Mb for F. x ananassa, and ∼200 Mb each for the four wild species. Subsequently, a virtual reference genome termed FANhybrid_r1.2 was constructed by integrating the sequences of the four homoeologous subgenomes of F. x ananassa, from which heterozygous regions in the Roche 454 and Illumina genome sequences were eliminated. The total length of FANhybrid_r1.2 thus created was 173.2 Mb with the N50 length of 5137 bp. The Illumina-assembled genome sequences of F. x ananassa and the four wild species were then mapped onto the reference genome, along with the previously published F. vesca genome sequence to establish the subgenomic structure of F. x ananassa. The strategy adopted in this study has turned out to be successful in dissecting the genome of octoploid F. x ananassa and appears promising when applied to the analysis of other polyploid plant species.     

Diabetic Complications in Obese Type 2 Diabetic Rat Models

We overviewed the pathophysiological features of diabetes and its complications in obese type 2 diabetic rat models: Otsuka Long-Evans Tokushima fatty (OLETF) rat, Wistar fatty rat, Zucker diabetic fatty (ZDF) rat and Spontaneously diabetic Torii (SDT) fatty rat. Pancreatic changes with progression of diabetes were classified into early changes, such as islet hypertrophy and degranulation of β cells, and degenerative changes, such as islet atrophy and fibrosis of islet with infiltration of inflammatory cells. Renal lesions in tubuli and glomeruli were observed, and nodular lesions in glomeruli were notable changes in OLETF and SDT fatty rats. Among retinal changes, folding and thickening were interesting findings in SDT fatty rats. A decrease of motor nerve conduction velocity with progression of diabetes was presented in obese diabetic rats. Other diabetic complications, osteoporosis and sexual dysfunction, were also observed. Observation of bone metabolic abnormalities, including decrease of osteogenesis and bone mineral density, and sexual dysfunction, including hypotestosteronemia and erectile dysfunction, in obese type 2 diabetic rats have been reported.     

Consumption of Green Tea,but Not Black Tea or Coffee,Is Associated with Reduced Risk of Cognitive Decline

Our objective was to determine whether the consumption of green tea, coffee, or black tea influences the incidence of dementia and mild cognitive impairment (MCI) in older people. We conducted a population-based prospective study with Japanese residents aged >60 years from Nakajima, Japan (the Nakajima Project). Participants received an evaluation of cognitive function and blood tests. The consumption of green tea, coffee, and black tea was also evaluated at baseline. Of 723 participants with normal cognitive function at a baseline survey (2007–2008), 490 completed the follow up survey in 2011–2013. The incidence of dementia during the follow-up period (mean ± SD: 4.9±0.9 years) was 5.3%, and that of MCI was 13.1%. The multiple-adjusted odds ratio for the incidence of overall cognitive decline (dementia or MCI) was 0.32 (95% CI: 0.16–0.64) among individuals who consumed green tea every day and 0.47 (95% CI: 0.25–0.86) among those who consumed green tea 1–6 days per week compared with individuals who did not consume green tea at all. The multiple-adjusted odds ratio for the incidence of dementia was 0.26 (95% CI: 0.06–1.06) among individuals who consumed green tea every day compared with those who did not consume green tea at all. No association was found between coffee or black tea consumption and the incidence of dementia or MCI. Our results indicate that green tea consumption is significantly associated with reduced risk of cognitive decline, even after adjustment for possible confounding factors.     

Induced Differentiation of Human Myeloid Leukemia Cells into M2 Macrophages by Combined Treatment with Retinoic Acid and 1α,25-Dihydroxyvitamin D3

Retinoids and 1α,25-dihydroxyvitamin D₃ (1,25(OH)₂D₃) induce differentiation of myeloid leukemia cells into granulocyte and macrophage lineages, respectively. All-trans retinoic acid (ATRA), which is effective in the treatment of acute promyelocytic leukemia, can induce differentiation of other types of myeloid leukemia cells, and combined treatment with retinoid and 1,25(OH)₂D₃ effectively enhances the differentiation of leukemia cells into macrophage-like cells. Recent work has classified macrophages into M1 and M2 types. In this study, we investigated the effect of combined treatment with retinoid and 1,25(OH)₂D₃ on differentiation of myeloid leukemia THP-1 and HL60 cells. 9-cis Retinoic acid (9cRA) plus 1,25(OH)₂D₃ inhibited proliferation of THP-1 and HL60 cells and increased myeloid differentiation markers including nitroblue tetrazolium reducing activity and expression of CD14 and CD11b. ATRA and the synthetic retinoic acid receptor agonist Am80 exhibited similar effects in combination with 1,25(OH)₂D₃ but less effectively than 9cRA, while the retinoid X receptor agonist HX630 was not effective. 9cRA plus 1,25(OH)₂D₃ effectively increased expression of M2 macrophage marker genes, such as CD163, ARG1 and IL10, increased surface CD163 expression, and induced interleukin-10 secretion in myeloid leukemia cells, while 9cRA alone had weaker effects on these phenotypes and 1,25(OH)₂D₃ was not effective. Taken together, our results demonstrate selective induction of M2 macrophage markers in human myeloid leukemia cells by combined treatment with 9cRA and 1,25(OH)₂D₃.     

Estimating the population structure of brown bears in eastern Hokkaido based on microsatellite analysis

Estimating the genetic structure of a population is important for the conservation and management of wildlife. In the present study, our aim was to estimate the genetic structure of the brown bear (Ursus arctos) population in eastern Hokkaido by performing a Bayesian clustering analysis. To accomplish this goal, we used 15 microsatellites to generate genotypic data from tissue samples collected from 646 bears between 1996 and 2008. Using this genotypic data and the geographic locations where the bears were captured, GENELAND analysis detected six subpopulations. Based on the genotypic data, the STRUCTURE analysis revealed three subpopulations. As inferred from the GENELAND analysis, the core zones of the subpopulations (G-a through G-f) were located in the Shiranuka Hills (G-a), the northern area of the Shiranuka Hills (G-b), the eastern slope of the Daisetsuzan Mountains (G-c), the northern slope of the Akan Mountain Range (G-d), the Shiretoko Peninsula (G-e), and Akkeshi District (G-f). The STRUCTURE analysis indicated that G-b and G-d were influenced by gene flow from other subpopulations. National routes, towns, and farm fields were considered to have formed the distribution boundaries among the subpopulations. A high level of genetic differentiation was not observed among the six subpopulations, with the exception of G-f (F _st?=?1.35–0.176, D _s?=?0.246–0.349), which showed a geographically discontinuous distribution. We suggest that the loss of forest areas through future regional development and road building should be avoided to facilitate gene flow in brown bears in Hokkaido.     

A novel phospholipase A1 with sequence homology to a mammalian Sec23p-interacting protein, p125.

p125, a mammalian Sec23p-interacting protein, exhibits sequence homology with bovine testis phosphatidic acid-preferring phospholipase A(1). In this study, we identified and characterized a new homologue of p125, KIAA0725p. KIAA0725p exhibited remarkable sequence similarity with p125 throughout the entire sequence determined but lacked an N-terminal proline-rich, Sec23p-interacting region. In vitro binding analysis showed that KIAA0725p does not bind to Sec23p. KIAA0725p possessed phospholipase A(1) activity preferentially for phosphatidic acid. We examined the effects of overexpression of KIAA0725p on the morphology of organelles. Overexpression of KIAA0725p, like that of p125, caused dispersion of the endoplasmic reticulum-Golgi intermediate compartment and Golgi apparatus. Different from the case of p125, overexpression of KIAA0725p resulted in dispersion of tethering proteins located in the Golgi region and caused aggregation of the endoplasmic reticulum. Our results indicate that KIAA0725p is a new member of the phosphatidic acid-preferring phospholipase A(1) protein family and suggest that the cellular function of KIAA0725p is different from that of p125.     

Notes on paternal care and sibling cannibalism in the giant water bug, Lethocerus deyrolli (Heteroptera: Belostomatidae)

Males of the giant water bug, Lethocerus deyrolli, care for egg masses on vegetation above the water surface. They supply the developing eggs with water and guard them against predators. In the present study, mechanisms by which paternal care is extended were found. Males were found situated just below the water on the natal substrate (usually a stick), and the first instar nymphs were aggregated around the substrate. When disturbed, the males showed aggressive behavior, threatening the intruder with their forelegs. Nymphs up to 12 h old did not attack the offered sibling nymphs or anuran larvae, which are common prey in the field. The 24 h‐old nymphs attacked both prey animals; however, they preferred anuran larvae. Cannibalistic behavior in the nymphs was well developed 72 h after hatching, when the nymphs had already dispersed from the natal substrate. The suppression of sibling cannibalism in younger nymphs would promote the maintenance of tight nymphal aggregations and consequently extend male care in this predatory species.