Ribosomal protein S3 is secreted as a homodimer in cancer cells

Protein secretion is a general phenomenon by which cells communicate with the extracellular environment. Secretory proteins, including hormones, enzymes, toxins, and antimicrobial peptides have various functions in extracellular environments. Here, we determined that ribosomal protein S3 (rpS3) is homodimerized and secreted in several cancer cell lines such as HT1080 (human fibrosarcoma) and MPC11 (mouse plasmacytoma). Moreover, we found that the secreted rpS3 protein increased in doxorubicin-resistant MPC11 cells compared to that in MPC11 cells. In addition, we also detected that the level of secreted rpS3 increased in more malignant cells, which were established with continuous exposure of cigarette smoke condensate. These findings suggest that the secreted rpS3 protein is an indicator of malignant tumors.     

Directed evolution and characterization of atrazine chlorohydrolase variants with enhanced activity

Atrazine chlorohydrolase (AtzA, EC 3.8.1.8) has attracted widespread interests as it catalyzes conversion of toxic atrazine to nontoxic hydroxyatrazine and can be used in the biodegradation of atrazine. To facilitate this application, a Haematococcus pluvialis-based method was applied to screen AtzA variants from a random mutagenesis library. Eight variants with enhanced enzyme activity were obtained. They showed 2.7- to 5.0-fold increase in specific activity compared with the wild type. Sequencing revealed that the two most active variants contained single substitution at Val12 and Leu395, respectively, while several improved variants contained substitutions at the four sites of Met315, His399, Asn429, and Val466 simultaneously, indicating that these residues contribute to the enzyme activity of AtzA. Kinetic analysis showed that five variants decreased the K _m value 0.6- to 0.9-fold, whereas all the variants increased the catalytic efficiency (k _cat/K _m value) 2.5- to 4.1-fold compared to the wild type. The modeled three-dimensional structure showed that AtzA is comprised of a typical (β/α)₈ domain of the amidohydrolase superfamily and a dual β-sheet domain. An iron ion and five ligand-binding residues are located in the β-barrel core of the (β/α)₈ domain. Some substituted residues are involved in hydrogen bond formation in the (β/α)₈-neighboring β-sheet.     

Early manipulation of juvenile hormone has sexually dimorphic effects on mature adult behavior in Drosophila melanogaster

Hormones are critical for the development, maturation, and maintenance of physiological systems; therefore, understanding their involvement during maturation of the brain is important for the elucidation of mechanisms by which adults become behaviorally competent. Changes in exogenous and endogenous factors encountered during sexual maturation can have long lasting effects in mature adults. In this study, we investigated the role of the gonadotropic hormone, juvenile hormone (JH), in the modulation of adult behaviors in Drosophila. Here we utilized methoprene (a synthetic JH analog) and precocene (a JH synthesis inhibitor) to manipulate levels of JH in sexually immature male and female Drosophila with or without decreased synthesis of neuronal dopamine (DA). Locomotion and courtship behavior were assayed once the animals had grown to sexual maturity. The results demonstrate a sexually dimorphic role for JH in the modulation of these centrally controlled behaviors in mature animals that is dependent on the age of the animals assayed, and present DA as a candidate neuronal factor that differentially interacts with JH depending on the sex of the animal. The data also suggest that JH modulates these behaviors through an indirect mechanism. Since gonadotropic hormones and DA interact in mammals to affect brain development and later function, our results suggest that this mechanism for the development of adult behavioral competence may be evolutionarily conserved.     

miR‐34c works downstream of p53 leading to dairy goat male germline stem‐cell (mGSCs) apoptosis

Objectives

Recent lines of evidence have indicated that miR‐34c can play important roles in regulation of the cell cycle, cell senescence and apoptosis of mouse and human tumour cells, spermatogenesis, and male germ‐cell apoptosis. However, there is little information on the effects of miR‐34c on proliferation and apoptosis of livestock male germ cells. The dairy goat is a convenient domestic species for biological investigation and application. The purpose of this study was to investigate the effects of miR‐34c on apoptosis and proliferation of dairy goat male germline stem cells (mGSCs), as well as to determine the relationship between p53 and miR‐34c in this species.

Materials and methods

Morphological observation, miRNA in situ hybridisation (ISH), bromodeoxyuridine staining, flow cytometry, quantitative‐RT‐PCR (Q‐RT‐PCR) and western blotting were utilized to ascertain apoptosis and proliferation of mGSCs, through transfection of miR‐34c mimics (miR‐34c), miR‐34c inhibitor (anti‐miR‐34c), miR‐34c mimics and inhibitors co‐transfected (mixture) compared to control groups.

Results

Results manifested that miR‐34c over‐expression promoted mGSCs apoptosis and suppressed their proliferation. Simultaneously, a variety of apoptosis‐related gene expression was increased while some proliferation‐related genes were downregulated. Accordingly, miR‐34c promoted apoptosis in mGSCs and reduced their proliferation; moreover, expression of miR‐34c was p53‐dependent.

Conclusions

This study is the first to provide a model for study of miRNAs and mechanisms of proliferation and apoptosis in male dairy goat germ cells.

     

Design and synthesis of 2-N-substituted indazolone derivatives as non-carboxylic acid glycogen synthase activators

Glycogen synthase (GS) catalyzes the transfer of glucose residues from UDP-glucose to a glycogen polymer chain, a critical step for glucose storage. Patients with type 2 diabetes normally exhibit low glycogen levels and decreased muscle glucose uptake is the major defect in whole body glucose disposal. Therefore, activating GS may provide a potential approach for the treatment of type 2 diabetes. In order to identify non-carboxylic acids GS activators, we designed and synthesized a series of 2-N-alkyl- and 2-N-aryl-indazolone derivatives and studied their activity in activating human GS.     

Therapeutic and pharmacokinetic characterizations of an anti-amyloidogenic bis-styrylbenzene derivative for Alzheimer’s disease treatment

Alzheimer’s disease drug discovery regarding exploration into the molecules and processes has focused on the intrinsic causes of the brain disorder correlated with the accumulation of amyloid-β. An anti-amyloidogenic bis-styrylbenzene derivative, KMS80013, showed excellent oral bioavailability (F = 46.2%), facilitated brain penetration (26%, iv) in mouse and target specific in vivo efficacy in acute AD mouse model attenuating the cognitive deficiency in Y-maze test. Acute toxicity (LD₅₀ >2000 mg/kg) and hERG channel inhibition (14% at 10 μM) results indicated safety of KMS80013.     

Multispecies coexistence of trees in tropical forests: spatial signals of topographic niche differentiation increase with environmental heterogeneity

Neutral and niche theories give contrasting explanations for the maintenance of tropical tree species diversity. Both have some empirical support, but methods to disentangle their effects have not yet been developed. We applied a statistical measure of spatial structure to data from 14 large tropical forest plots to test a prediction of niche theory that is incompatible with neutral theory: that species in heterogeneous environments should separate out in space according to their niche preferences. We chose plots across a range of topographic heterogeneity, and tested whether pairwise spatial associations among species were more variable in more heterogeneous sites. We found strong support for this prediction, based on a strong positive relationship between variance in the spatial structure of species pairs and topographic heterogeneity across sites. We interpret this pattern as evidence of pervasive niche differentiation, which increases in importance with increasing environmental heterogeneity.     

Predictive systems ecology

Human societies, and their well-being, depend to a significant extent on the state of the ecosystems that surround them. These ecosystems are changing rapidly usually in response to anthropogenic changes in the environment. To determine the likely impact of environmental change on ecosystems and the best ways to manage them, it would be desirable to be able to predict their future states. We present a proposal to develop the paradigm of predictive systems ecology, explicitly to understand and predict the properties and behaviour of ecological systems. We discuss the necessary and desirable features of predictive systems ecology models. There are places where predictive systems ecology is already being practised and we summarize a range of terrestrial and marine examples. Significant challenges remain but we suggest that ecology would benefit both as a scientific discipline and increase its impact in society if it were to embrace the need to become more predictive.     

Structural Mechanism of CCM3 Heterodimerization with GCKIII Kinases

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Highlights? Crystal structure of CCM3-MST4 heterodimeric complex ? Structural mechanism driving CCM3-GCKIII heterodimerization ? Conformational changes required for CCM3-GCKIII heterodimerization ? Synergistic effects of CCM3-MST4 complex on cell proliferation and migration