Kinetoplastid kinetochore proteins KKT2 and KKT3 have unique centromere localization domains

The kinetochore is the macromolecular protein complex that assembles onto centromeric DNA and binds spindle microtubules. Evolutionarily divergent kinetoplastids have an unconventional set of kinetochore proteins. It remains unknown how kinetochores assemble at centromeres in these organisms. Here, we characterize KKT2 and KKT3 in the kinetoplastid parasite Trypanosoma brucei. In addition to the N-terminal kinase domain and C-terminal divergent polo boxes, these proteins have a central domain of unknown function. We show that KKT2 and KKT3 are important for the localization of several kinetochore proteins and that their central domains are sufficient for centromere localization. Crystal structures of the KKT2 central domain from two divergent kinetoplastids reveal a unique zinc-binding domain (termed the CL domain for centromere localization), which promotes its kinetochore localization in T. brucei. Mutations in the equivalent domain in KKT3 abolish its kinetochore localization and function. Our work shows that the unique central domains play a critical role in mediating the centromere localization of KKT2 and KKT3.     

Triiodothyronine induces UCP-1 expression and mitochondrial biogenesis in human adipocytes

Uncoupling protein (UCP)-1 expressed in brown adipose tissue plays an important role in thermogenesis. Recent data suggest that brown-like adipocytes in white adipose tissue (WAT) and skeletal muscle play a crucial role in the regulation of body weight. Understanding of the mechanism underlying the increase in UCP-1 expression level in these organs should, therefore, provide an approach to managing obesity. The thyroid hormone (TH) has profound effects on mitochondrial biogenesis and promotes the mRNA expression of UCP in skeletal muscle and brown adipose tissue. However, the action of TH on the induction of brown-like adipocytes in WAT has not been elucidated. Thus we investigate whether TH could regulate UCP-1 expression in WAT using multipotent cells isolated from human adipose tissue. In this study, triiodothyronine (T(3)) treatment induced UCP-1 expression and mitochondrial biogenesis, accompanied by the induction of the CCAAT/enhancer binding protein, peroxisome proliferator-activated receptor-γ coactivator-1α, and nuclear respiratory factor-1 in differentiated human multipotent adipose-derived stem cells. The effects of T(3) on UCP-1 induction were dependent on TH receptor-β. Moreover, T(3) treatment increased oxygen consumption rate. These findings indicate that T(3) is an active modulator, which induces energy utilization in white adipocytes through the regulation of UCP-1 expression and mitochondrial biogenesis. Our findings provide evidence that T(3) serves as a bipotential mediator of mitochondrial biogenesis.     

Ovarian hormones regulate expression of the focal adhesion proteins,talin and paxillin,in rat uterine luminal but not glandular epithelial cells

During early pregnancy in the rat, focal adhesions disassemble in uterine luminal epithelial cells at the time of implantation to facilitate their removal so that the implanting blastocyst can invade into the underlying endometrial decidual cells. This study investigated the effect of ovarian hormones on the distribution and protein expression of two focal adhesion proteins, talin and paxillin, in rat uterine luminal and glandular epithelial cells under various hormone regimes. Talin and paxillin showed a major distributional change between different hormone regimes. Talin and paxillin were highly concentrated along the basal cell surface of uterine luminal epithelial cells in response to oestrogen treatment. However, this prominent staining of talin and paxillin was absent and also a corresponding reduction of paxillin expression was demonstrated in response to progesterone alone or progesterone in combination with oestrogen, which is also observed at the time of implantation. In contrast, the distribution of talin and paxillin in uterine glandular epithelial cells was localised on the basal cell surface and remained unchanged in all hormone regimes. Thus, not all focal adhesions are hormonally dependent in the rat uterus; however, the dynamics of focal adhesion in uterine luminal epithelial cells is tightly regulated by ovarian hormones. In particular, focal adhesion disassembly in uterine luminal epithelial cells, a key component to establish successful implantation, is predominantly under the influence of progesterone.     

Language discrimination by Java sparrows

Java sparrows (Padda oryzivora) were trained to discriminate English from Chinese spoken by a bilingual speaker. They could learn discrimination and showed generalization to new sentences spoken by the same speaker and those spoken by a new speaker. Thus, the birds distinguished between English and Chinese. Although auditory cues for the discrimination were not specified, this is the first evidence that non-mammalian species can discriminate human languages.     

Comparative morphology and development of bony elements in the head region in three species of Japanese catfishes (Silurus: Siluridae; Siluriformes)

The shape and development of bony elements of the neurocranium and suspensorium were studied in three species of Japanese catfish (Silurus) from the viewpoint of comparative morphology. InS. asotus andS. biwaensis the order of appearance of the bony elements was similar, but the ossification of most elements was delayed inS. lithophilus. The neurocranium and Suspensorium of adultS. lithophilus retain juvenile features compared with the other two species. On the other hand, in the skull ofS. biwaensis the sagittal crest of the supraoccipital, the ridge of the pterotic, and the hyomandibular process are more developed than in the other two species.     

Phenotypic changes associated with RNA interference silencing of chalcone synthase in apple (Malus × domestica)

We have identified in apple (Malus × domestica) three chalcone synthase (CHS) genes. In order to understand the functional redundancy of this gene family RNA interference knockout lines were generated where all three of these genes were down‐regulated. These lines had no detectable anthocyanins and radically reduced concentrations of dihydrochalcones and flavonoids. Surprisingly, down‐regulation of CHS also led to major changes in plant development, resulting in plants with shortened internode lengths, smaller leaves and a greatly reduced growth rate. Microscopic analysis revealed that these phenotypic changes extended down to the cellular level, with CHS‐silenced lines showing aberrant cellular organisation in the leaves. Fruit collected from one CHS‐silenced line was smaller than the ‘Royal Gala’ controls, lacked flavonoids in the skin and flesh and also had changes in cell morphology. Auxin transport experiments showed increased rates of auxin transport in a CHS‐silenced line compared with the ‘Royal Gala’ control. As flavonoids are well known to be key modulators of auxin transport, we hypothesise that the removal of almost all flavonoids from the plant by CHS silencing creates a vastly altered environment for auxin transport to occur and results in the observed changes in growth and development.     

A Novel Nectin-mediated Cell Adhesion Apparatus That Is Implicated in Prolactin Receptor Signaling for Mammary Gland Development

Mammary gland development is induced by the actions of various hormones to form a structure consisting of collecting ducts and milk-secreting alveoli, which comprise two types of epithelial cells known as luminal and basal cells. These cells adhere to each other by cell adhesion apparatuses whose roles in hormone-dependent mammary gland development remain largely unknown. Here we identified a novel cell adhesion apparatus at the boundary between the luminal and basal cells in addition to desmosomes. This apparatus was formed by the trans-interaction between the cell adhesion molecules nectin-4 and nectin-1, which were expressed in the luminal and basal cells, respectively. Nectin-4 of this apparatus further cis-interacted with the prolactin receptor in the luminal cells to enhance the prolactin-induced prolactin receptor signaling for alveolar development with lactogenic differentiation. Thus, a novel nectin-mediated cell adhesion apparatus regulates the prolactin receptor signaling for mammary gland development.     

Particle inflow gun-mediated transformation of multiple-shoot clumps in rhodes grass (Chloris gayana)

Rhodes grass (Chloris gayana) is one of the most important warm-season forage grasses. It is cultivated in tropical and subtropical parts of the world and is mostly used for grazing and hay production. We have established a particle-bombardment transformation protocol for rhodes grass using multiple-shoot clumps (MSCs) as the target tissue. A vector pAHC25 containing a herbicide-resistance gene (bar) together with the beta-glucuronidase (GUS) gene was used in transformation experiments. The most efficient recovery of bialaphos-resistant tissue was achieved when the bombarded MSCs were first cultured for 15 d on bialaphos-free medium before being subjected to selection pressure. The resistant tissues regenerated transgenic plants that displayed GUS gene expression. Under optimized conditions, 251 target pieces yielded 46 transgenic plants from 4 independent transgenic lines.     

Modulation of immune responses by Plasmodium falciparum infection in asymptomatic children living in the endemic region of Mbita,western Kenya

Individuals living in malaria endemic areas become clinically immune after multiple re-infections over time and remain infected without apparent symptoms. However, it is unclear why a long period is required to gain clinical immunity to malaria, and how such immunity is maintained. Although malaria infection is reported to induce inhibition of immune responses, studies on asymptomatic individuals living in endemic regions of malaria are relatively scarce. We conducted a cross-sectional study of immune responses in asymptomatic school children aged 4–16 years living in an area where Plasmodium falciparum and Schistosoma mansoni infections are co-endemic in Kenya. Peripheral blood mononuclear cells were subjected to flow cytometric analysis and cultured to determine proliferative responses and cytokine production. The proportions of cellular subsets in children positive for P. falciparum infection at the level of microscopy were comparable to the negative children, except for a reduction in central memory-phenotype CD8⁺ T cells and natural killer cells. In functional studies, the production of cytokines by peripheral blood mononuclear cells in response to P. falciparum crude antigens exhibited strong heterogeneity among children. In addition, production of IL-2 in response to anti-CD3 and anti-CD28 monoclonal antibodies was significantly reduced in P. falciparum-positive children as compared to -negative children, suggesting a state of unresponsiveness. These data suggest that the quality of T cell immune responses is heterogeneous among asymptomatic children living in the endemic region of P. falciparum, and that the responses are generally suppressed by active infection with Plasmodium parasites.     

A Novel Cell-Sheet Technology That Achieves Durable Factor VIII Delivery in a Mouse Model of Hemophilia A

Gene- or cell-based therapies aimed at creating delivery systems for coagulation factor VIII (FVIII) protein have emerged as promising options for hemophilia A treatment. However, several issues remain to be addressed regarding the efficacies and adverse events of these new classes of therapies. To improve an existing cell-based therapy involving the subcutaneous transplantation of FVIII-transduced blood outgrowth endothelial cells (BOECs), we employed a novel cell-sheet technology that allows individual dispersed cells to form a thin and contiguous monolayer without traditional bioabsorbable scaffold matrices. Compared to the traditional methodology, our cell-sheet approach resulted in longer-term and 3–5-fold higher expression of FVIII (up to 11% of normal) in recipient hemophilia A mice that lacked a FVIII humoral immune response due to transient immunosuppression with cyclophosphamide. Histological studies revealed that the transplanted BOEC sheets were structured as flat clusters, supporting the long-term expression of therapeutic FVIII in plasma from an ectopic subcutaneous space. Our novel tissue-engineering approach using genetically modified BOEC sheets could aid in development of cell-based therapy that will allow safe and effective in vivo delivery of functional FVIII protein in patients with hemophilia A.