Behavioral phenotypes of Disc1 missense mutations in mice

To support the role of DISC1 in human psychiatric disorders, we identified and analyzed two independently derived ENU-induced mutations in Exon 2 of mouse Disc1. Mice with mutation Q31L showed depressive-like behavior with deficits in the forced swim test and other measures that were reversed by the antidepressant bupropion, but not by rolipram, a phosphodiesterase-4 (PDE4) inhibitor. In contrast, L100P mutant mice exhibited schizophrenic-like behavior, with profound deficits in prepulse inhibition and latent inhibition that were reversed by antipsychotic treatment. Both mutant DISC1 proteins exhibited reduced binding to the known DISC1 binding partner PDE4B. Q31L mutants had lower PDE4B activity, consistent with their resistance to rolipram, suggesting decreased PDE4 activity as a contributory factor in depression. This study demonstrates that Disc1 missense mutations in mice give rise to phenotypes related to depression and schizophrenia, thus supporting the role of DISC1 in major mental illness.     

A case of fibrosarcoma on the perivertebral surface of a ferret with hind limb paralysis

A 2.5 year-old female ferret had a stiff palpable mass arising from the dorsal surface of the thoracic (T) to lumbar (L) vertebrae with paralysis of the hind limbs. By myelography the dorsal and ventral lines of contrast were not observed in the area forwarded of L3. Grossly, the tumor encircled the dorsal vertebrae. Microscopically, tumor cells were proliferated intimately and were attached to the vertebrae surface involving surrounding fatty and connective tissues. The tumor consisted of fibroblastic cells with prominent cellular atypia. The bromodeoxyuridine (BrdU) labeling index to examine cellular kinetics was high (11.8%). Based on macro and micropathological features, the present tumor was diagnosed as periosteal fibrosarcoma arising from perivertebral connective tissue.     

Distinct role for CD8 T cells toward cutaneous tumors and visceral metastases

The growth of immunogenic tumors in immunocompetent individuals is one of the oldest conundrums in tumor immunology. Although the ability of mouse CD8+ T cells to control transplanted tumors is well documented, little is known about their impact on autochthonous tumors. To gain insight into the role of CD8+ T cells during the course of cancer development, we produced a novel model of spontaneous melanoma. The metallothionein (MT)-ret/AAD mouse is transgenic for the RET oncogene and the chimeric MHC molecule AAD (alpha1-alpha2 domains of HLA-A2 linked to alpha3 domain of H2-Dd). This model recapitulates the natural history of human melanoma, and expression of the AAD molecule makes it suitable for analyzing CD8+ T cell responses directed against peptide Ags that have been previously identified in HLA-A2+ melanoma patients. We found that, as tumors grow, mice develop a broad melanoma-specific CD8+ T cell response. Occurrence of cutaneous nodules is not affected by CD8+ T cell depletion, showing that although CD8+ T cells are functional, they have no effect on established cutaneous tumors. However, depleted mice die from visceral disease much earlier than controls, showing that CD8+ T cells control metastasis spreading and disease progression. Antigenic modulation is observed in visceral metastases, suggesting that visceral nodules may be subject to immunoediting. Our data demonstrate that growth of melanoma in the MT-ret/AAD model involves several tolerance mechanisms sequentially. They also reveal a different role for CD8+ T cells toward early stage of cutaneous tumors and late visceral metastatic stage of the disease.     

From stimulus estimation to combination sensitivity: encoding and processing of amplitude and timing information in parallel,convergent sensory pathways

Information theoretical approaches to sensory processing in electric fish have focused on the encoding of amplitude modulations in a single sensory pathway in the South American gymnotiforms. To assess the generality of these studies, we investigated the encoding of amplitude and phase modulations in the distantly related African fish Gymnarchus. In both the amplitude- and time-coding pathways, primary afferents accurately estimated the time course of random modulations whereas hindbrain neurons extracted information about specific stimulus features. Despite exhibiting a clear preference for encoding amplitude or phase, afferents and hindbrain neurons could encode significant amounts of modulation of their nonpreferred attribute. Although no increase in feature extraction performance occurred where the two pathways converge in the midbrain, neurons there were increasingly sensitive to simultaneous modulation of both attributes. A shift from accurate stimulus estimation in the periphery to increasingly sparse representations of specific features appears to be a general strategy in electrosensory processing.     

NTH201, a novel class II KNOTTED1-like protein, facilitates the cell-to-cell movement of Tobacco mosaic virus in tobacco

NTH201, a novel class II KNOTTED1-like protein gene, was cloned from tobacco (Nicotiana tabacum cv. Xanthi) and its role in Tobacco mosaic virus (TMV) infection was analyzed. Virus-induced gene silencing of NTH201 caused a delay in viral RNA accumulation as well as virus spread in infected tobacco plants. Overexpression of the gene in a transgenic tobacco plant (N. tabacum cv. Xanthi nc) infected by TMV showed larger local lesions than those of the nontransgenic plant. NTH201 exhibited no intercellular trafficking ability but did exhibit colocalization with movement protein (MP) at the plasmodesmata. When NTH201-overexpressing tobacco BY-2 cultured cells were infected with TMV, the accumulation of MP but not of viral genomic and subgenomic RNA clearly was accelerated compared with those in nontransgenic cells at an early infection period. The formation of virus replication complexes (VRC) also was accelerated in these transgenic cells. Conversely, NTH201-silenced cells showed less MP accumulations and fewer VRC formations than did nontransgenic cells. These results suggested that NTH201 might indirectly facilitate MP accumulation and VRC formation in TMV-infected cells, leading to rapid viral cell-to-cell movement in plants at an early infection stage.     

SOSUI-GramN: high performance prediction for sub-cellular localization of proteins in gram-negative bacteria

A predictive software system, SOSUI-GramN, was developed for assessing the subcellular localization of proteins in Gram-negative bacteria. The system does not require the sequence homology data of any known sequences; instead, it uses only physicochemical parameters of the N- and C-terminal signal sequences, and the total sequence. The precision of the prediction system for subcellular localization to extracellular, outer membrane, periplasm, inner membrane and cytoplasmic medium was 92.3%, 89.4%, 86.4%, 97.5% and 93.5%, respectively, with corresponding recall rates of 70.3%, 87.5%, 76.0%, 97.5% and 88.4%, respectively. The overall performance for precision and recall obtained using this method was 92.9% and 86.7%, respectively. The comparison of performance of SOSUI-GramN with that of other methods showed the performance of prediction for extracellular proteins, as well as inner and outer membrane proteins, was either superior or equivalent to that obtained with other systems. SOSUI-GramN particularly improved the accuracy for predictions of extracellular proteins which is an area of weakness common to the other methods.     

Adaptive significance of self-fertilization in a hermaphroditic perennial, Trillium camschatcense (Melanthiaceae)

The evolution of self-fertilization from primarily outcrossing ancestors is one of the most common evolutionary transitions in plants; however, the ecological mechanisms that maintain self-fertilization have remained controversial. Theoretical studies suggest that selfing is advantageous over outcrossing in terms of genetic transmission and assurance of seed production under pollen-limited circumstances. Trillium camschatcense is a herbaceous perennial distributed in Hokkaido and northern Honshu, Japan. Geographical variation in the breeding system (self-compatible, SC; or self-incompatible, SI) has been reported in populations in Hokkaido. Here, we used several SC and SI populations of T. camschatcense to investigate the adaptive significance and the evolutionary basis of self-fertilization. Pollination experiments and genetic analyses demonstrated that the potential availability of outcross pollen in SC populations was sufficient and that the number of pollen donors was equal to that of SI populations. However, despite the high availability of outcross pollen, the SC populations produced seeds predominantly by selfing and so underwent severe inbreeding depression. Although none of the suggested advantages for self-fertilization were supported by our analyses, we propose two possible scenarios for the evolution of self-fertilization in T. camschatcense.     

Indole derivatives sustain embryonic stem cell self-renewal in long-term culture

Embryonic stem cells (ESCs), which have characteristics such as self-renewal, indefinite proliferation, and pluripotency, are thought to hold great promise for regenerative medicine. ESCs are generally cultured on mouse embryonic fibroblast (MEF) or MEF conditioned medium (MEF-CM). However, for therapeutic applications, it is preferable for ESCs to be cultured under chemically defined conditions. Here, we report synthetic compounds that allow expansion of undifferentiated mouse ESCs in the absence of MEF, Leukemia Inhibitory Factor (LIF), and Fetal Bovine Serum (FBS). ESCs cultured for more than 30 d in a serum-free medium supplemented with indole derivertives retained their characteristic morphology and expressed markers such as SSEA-1, OCT3/4, Rex-1, Sox2, and Nanog. They consistently differentiated into many types of cells, including neurons, muscle cells, and hepatocytes. These results indicate that our compounds provide a more efficient and safer large-scale culture system for pluripotent ESCs, and hence might contribute to the use of ESCs in therapeutic applications.     

Genetic structure in aquatic bladderworts: clonal propagation and hybrid perpetuation

• Background and Aims The free-floating aquatic bladderwort Utricularia australis f. australis is a sterile F₁ hybrid of U. australis f. tenuicaulis and U. macrorhiza. However, co-existence of the hybrids and parental species has not been observed. In the present study, the following questions are addressed. (a) Does the capacity of the two parental species to reproduce sexually contribute to higher genotypic diversity than that of sterile F₁ hybrid? (b) Are there any populations where two parental species and their hybrid co-exist? (c) If not, where and how do hybrids originate?• Methods The presence and absence of Utricularia was thoroughly investigated in two regions in Japan. An amplified fragment length polymorphism (AFLP) analysis was conducted for 397 individuals collected from all populations (33 in total) where Utricularia was observed.• Key Results The mean number of genotypes per population (G) and genotypic diversity (D) were extremely low irrespective of the capacity to reproduce sexually: G was 1·1–1·2 and D was 0·02–0·04. The hybrid rarely co-existed with either parental species, and the co-existence of two parental species was not observed. Several AFLP bands observed in the hybrid are absent in both parental genotypes, and parent and hybrid genotypes in the same region do not show greater genetic similarity than those in distant regions.• Conclusions The capacity to reproduce sexually in parental species plays no role in increasing genotypic diversity within populations. The observed genotypes of the hybrid could not have originated from hybridization between the extant parental genotypes within the study regions. Considering the distribution ranges of three investigated taxa, it is clear that the hybrid originated in the past, and hybrid populations have been maintained exclusively by clonal propagation, which may be ensured by both hybrid vigor and long-distance dispersal of clonal offspring.     

Enzymatic synthesis of a novel cyclic pentasaccharide consisting of alpha-D-glucopyranose with 6-alpha-glucosyltransferase and 3-alpha-isomaltosyltransferase

A novel cyclic pentasaccharide (CPS) and a branched cyclic pentasaccharide (6G-CPS) consisting of d-glucopyranose were synthesized with 6-alpha-glucosyltransferase (6GT) and 3-alpha-isomaltosyltransferase (IMT) from Bacillus globisporus N75. The structure of CPS was cyclo-[-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->]. The other, 6G-CPS, had the structure cyclo-[-->6)-alpha-D-Glcp-(1-->3)-alpha-D-Glcp-(1-->6)-alpha-D-Glcp-(1-->3)-[alpha-D-Glcp-(1-->6)]-alpha-D-Glcp-(1-->4)-alpha-D-Glcp-(1-->]. The formation of CPS was presumed to occur after the following four successive reactions: a 6-glucosyltransfer reaction with 6GT, a 4-glucosyltransfer reaction with 6GT, a 3-isomaltosyltransfer reaction with IMT, and a cyclization reaction with IMT.