Body‐colour variation in an orb‐web spider and its effect on predation success

Animal body coloration serves several functions such as thermoregulation, camouflage, aposematism, and intraspecific communication. In some orb‐web spiders, bright and conspicuous body colours are used to attract prey. On the other hand, there are other species whose body colour does not attract prey. Using a spider species showing individual body‐colour variation, the present study aimed to determine whether or not the variation in body colour shows a correlation with predation rates. We studied the orb‐web spider (Cyclosa argenteoalba) using both field observations and T‐maze experiments, in which the prey were exposed to differently coloured spiders. Cyclosa argenteoalba has silver‐ and black‐coloured areas on its dorsal abdomen, with the ratio of these two colours varying continuously among individuals. The bright and conspicuous silver area reflects ultraviolet light. Results of both field observations and colour choice experiments using Drosophila flies as prey showed that darker spiders have a greater chance of capturing prey than silver spiders. This indicates that body‐colour variation affects predation success among individuals and that the bright silver colour does not function to attract prey in C. argenteoalba.     

Small‐molecule auxin inhibitors that target YUCCA are powerful tools for studying auxin function

Auxin is essential for plant growth and development, this makes it difficult to study the biological function of auxin using auxin‐deficient mutants. Chemical genetics have the potential to overcome this difficulty by temporally reducing the auxin function using inhibitors. Recently, the indole‐3‐pyruvate (IPyA) pathway was suggested to be a major biosynthesis pathway in Arabidopsis thaliana L. for indole‐3‐acetic acid (IAA), the most common member of the auxin family. In this pathway, YUCCA, a flavin‐containing monooxygenase (YUC), catalyzes the last step of conversion from IPyA to IAA. In this study, we screened effective inhibitors, 4‐biphenylboronic acid (BBo) and 4‐phenoxyphenylboronic acid (PPBo), which target YUC. These compounds inhibited the activity of recombinant YUC in vitro, reduced endogenous IAA content, and inhibited primary root elongation and lateral root formation in wild‐type Arabidopsis seedlings. Co‐treatment with IAA reduced the inhibitory effects. Kinetic studies of BBo and PPBo showed that they are competitive inhibitors of the substrate IPyA. Inhibition constants (K_i) of BBo and PPBo were 67 and 56 nm , respectively. In addition, PPBo did not interfere with the auxin response of auxin‐marker genes when it was co‐treated with IAA, suggesting that PPBo is not an inhibitor of auxin sensing or signaling. We propose that these compounds are a class of auxin biosynthesis inhibitors that target YUC. These small molecules are powerful tools for the chemical genetic analysis of auxin function.     

Extensive and prolonged restoration of dystrophin expression with vivo-morpholino-mediated multiple exon skipping in dystrophic dogs

Duchenne muscular dystrophy (DMD) is a severe and the most prevalent form of muscular dystrophy, characterized by rapid progression of muscle degeneration. Antisense-mediated exon skipping is currently one of the most promising therapeutic options for DMD. However, unmodified antisense oligos such as morpholinos require frequent (weekly or bi-weekly) injections. Recently, new generation morpholinos such as vivo-morpholinos are reported to lead to extensive and prolonged dystrophin expression in the dystrophic mdx mouse, an animal model of DMD. The vivo-morpholino contains a cell-penetrating moiety, octa-guanidine dendrimer. Here, we sought to test the efficacy of multiple exon skipping of exons 6-8 with vivo-morpholinos in the canine X-linked muscular dystrophy, which harbors a splice site mutation at the boundary of intron 6 and exon 7. We designed and optimized novel antisense cocktail sequences and combinations for exon 8 skipping and demonstrated effective exon skipping in dystrophic dogs in vivo. Intramuscular injections with newly designed cocktail oligos led to high levels of dystrophin expression, with some samples similar to wild-type levels. This is the first report of successful rescue of dystrophin expression with morpholino conjugates in dystrophic dogs. Our results show the potential of phosphorodiamidate morpholino oligomer conjugates as therapeutic agents for DMD.     

Surface ��-1,3-Glucan Facilitates Fungal Stealth Infection by Interfering with Innate Immunity in Plants

Plants evoke innate immunity against microbial challenges upon recognition of pathogen-associated molecular patterns (PAMPs), such as fungal cell wall chitin. Nevertheless, pathogens may circumvent the host PAMP-triggered immunity. We previously reported that the ascomycete Magnaporthe oryzae, a famine-causing rice pathogen, masks cell wall surfaces with α-1,3-glucan during invasion. Here, we show that the surface α-1,3-glucan is indispensable for the successful infection of the fungus by interfering with the plant''s defense mechanisms. The α-1,3-glucan synthase gene MgAGS1 was not essential for infectious structure development but was required for infection in M. oryzae. Lack or degradation of surface α-1,3-glucan increased fungal susceptibility towards chitinase, suggesting the protective role of α-1,3-glucan against plants'' antifungal enzymes during infection. Furthermore, rice plants secreting bacterial α-1,3-glucanase (AGL-rice) showed strong resistance not only to M. oryzae but also to the phylogenetically distant ascomycete Cochlioborus miyabeanus and the polyphagous basidiomycete Rhizoctonia solani; the histocytochemical analysis of the latter two revealed that α-1,3-glucan also concealed cell wall chitin in an infection-specific manner. Treatment with α-1,3-glucanase in vitro caused fragmentation of infectious hyphae in R. solani but not in M. oryzae or C. miyabeanus, indicating that α-1,3-glucan is also involved in maintaining infectious structures in some fungi. Importantly, rapid defense responses were evoked (a few hours after inoculation) in the AGL-rice inoculated with M. oryzae, C. miyabeanus and R. solani as well as in non-transgenic rice inoculated with the ags1 mutant. Taken together, our results suggest that α-1,3-glucan protected the fungal cell wall from degradative enzymes secreted by plants even from the pre-penetration stage and interfered with the release of PAMPs to delay innate immune defense responses. Because α-1,3-glucan is nondegradable in plants, it is reasonable that many fungal plant pathogens utilize α-1,3-glucan in the innate immune evasion mechanism and some in maintaining the structures.     

Polymorphism of T-cell receptor genes among laboratory and wild mice: Diverse origins of laboratory mice

Southern blots of genomic DNA from 23 strains of laboratory mice and 19 individual wild mice were examined for restriction fragment length polymorphisms in their loci encoding the T-cell receptors (Tcr): the constant regions of the α, β, and γ chains (C _α,C _β, andC _γ) and a variable region family of the β chain (V _β8). Only a few polymorphisms were observed for each locus in the laboratory mice after using three restriction enzymes,Bam HI,Eco RI, andHind III. All the laboratory mice examined fall into one of two types for theC _α,C _β andV _β8 loci and one of three types for theC _γ. These types are found in some of the wild mice studied, indicating that they were already present in the founder mice of laboratory mouse strains. In contrast, theTcr genes are highly polymorphic among wild mice. Analysis of the polymorphisms in these loci suggests that laboratory mice have inherited their genes not only fromMus musculus domesticus, but also from other subspecies, and much more than previously believed from Asian subspecies.     

Scolecenchelys fuscogularis (Anguilliformes: Ophichthidae, Myrophinae), a new worm eel from Japan

A new species of worm eel (Ophichthidae, subfamily Myrophinae), Scolecenchelys fuscogularis, is described from two specimens collected at 90–147 m depth off the coast of Japan. The new species is characterized by its dorsal-fin origin, which is located posterior to a vertical through the anus, its high total number of vertebrae (146–149), and its uniserial dentition on jaws and vomer. The new species is similar to Scolecenchelys australis and Scolecenchelys tasmaniensis in having 148–152 total and 60–61 preanal vertebrae and its uniserial teeth, but can be distinguished from the latter two species as it has a larger head [8.5–8.8 % of total length (TL) vs. 7.8–8.3 %], a longer trunk (39 % TL vs. 34–35 %), and a shorter tail (52–53 % TL vs. 56–58 %). Although S. fuscogularis most resembles Scolecenchelys chilensis in having 146–159 total and 59–64 preanal vertebrae and uniserial teeth, as well as in the proportions of the head, trunk and tail, the new species differs from the latter in having a smaller head (8.5–8.8 % TL vs. 8.9–9.7 %), a more slender body (body depth 1.5–1.6 % TL vs. 2.3–2.9 %), a more posterior dorsal-fin origin (horizontal distance between the origin and a vertical through the anus 83 % of head length vs. 36–54 %), no groove on the ventral side of its snout, and a dark lower jaw with a patch of melanophores on the ventral side of its branchial basket.     

Decreased expression of VE-cadherin and claudin-5 and increased phosphorylation of VE-cadherin in vascular endothelium in nasal polyps

VE-cadherin and claudin-5 are major components of adherens and tight junctions of vascular endothelial cells and a decrease in their expression and an increase in the tyrosine-phosphorylation of VE-cadherin are associated with an increase in endothelial paracellular permeability. To clarify the mechanism underlying the development of edema in nasal polyps, we studied these molecules in polyp microvessels. Normal inferior turbinate mucosal tissues and nasal polyps from patients treated with or without glucocorticoid were stained for VE-cadherin or claudin-5 and CD31 by a double-immunofluorescence method and the immunofluorescence intensities were graded 1–3 with increasing intensity. To correct for differences in fluorescence intensity attributable to a different endothelial area being exposed in a section or to the thickness of a section, the relative immunofluorescence intensity was estimated by dividing the grade of VE-cadherin or claudin-5 by that of CD31 in each microvessel. Tyrosine-phosphorylation of VE-cadherin was examined by Western blot analysis. The relative intensities of VE-cadherin and claudin-5 in the CD31-positive microvessels significantly decreased in the following order; inferior turbinate mucosa, treated polyps and untreated polyps. The ratio of tyrosine-phosphorylated VE-cadherin to VE-cadherin was significantly higher in untreated polyps than in the inferior turbinate mucosa and treated polyps, between which no significant difference in the ratio was seen. Thus, in nasal polyps, the barrier function of endothelial adherens and tight junctions is weakened, although glucocorticoid treatment improves this weakened barrier function.     

Comparison between basal and apical dendritic spines in estrogen-induced rapid spinogenesis of CA1 principal neurons in the adult hippocampus

Modulation of hippocampal synaptic plasticity by estrogen has been attracting much attention. Here, we demonstrated the rapid effect of 17beta-estradiol on the density and morphology of spines in the stratum oriens (s.o., basal side) and in the stratum lacunosum-moleculare (s.l.m., apical side) by imaging Lucifer Yellow-injected CA1 neurons in adult male rat hippocampal slices, because spines in s.o. and s.l.m. have been poorly understood as compared with spines in the stratum radiatum. The application of 1nM estradiol-induced a rapid increase in the density of spines of pyramidal neurons within 2h. This increase by estradiol was blocked by Erk MAP kinase inhibitor and estrogen receptor inhibitor in both regions. Effect of blockade by agonists of AMPA receptors and NMDA receptors was different between s.o. and s.l.m. In both regions, ERalpha agonist PPT induced the same enhancing effect of spinogenesis as that induced by estradiol.     

Solution structure and functional importance of a conserved RNA hairpin of eel LINE UnaL2

The eel long interspersed element (LINE) UnaL2 and its partner short interspersed element (SINE) share a conserved 3′ tail that is critical for their retrotransposition. The predicted secondary structure of the conserved 3′ tail of UnaL2 RNA contains a stem region with a putative internal loop. Deletion of the putative internal loop region abolishes UnaL2 mobilization, indicating that this putative internal loop is required for UnaL2 retrotransposition; the exact role of the putative internal loop in retrotransposition, however, has not been elucidated. To establish a structure-based foundation on which to address the issue of the putative internal loop function in retrotransposition, we used NMR to determine the solution structure of a 36 nt RNA derived from the 3′ conserved tail of UnaL2. The region forms a compact structure containing a single bulged cytidine and a U–U mismatch. The bulge and mismatch region have conformational flexibility and molecular dynamics simulation indicate that the entire stem of the 3′ conserved tail RNA can anisotropically fluctuate at the bulge and mismatch region. Our structural and mutational analyses suggest that stem flexibility contributes to UnaL2 function and that the bulged cytidine and the U–U mismatch are required for efficient retrotransposition.