Multivariate multiple test procedures based on nonparametric copula estimation

Multivariate multiple test procedures have received growing attention recently. This is due to the fact that data generated by modern applications typically are high‐dimensional, but possess pronounced dependencies due to the technical mechanisms involved in the experiments. Hence, it is possible and often necessary to exploit these dependencies in order to achieve reasonable power. In the present paper, we express dependency structures in the most general manner, namely, by means of copula functions. One class of nonparametric copula estimators is constituted by Bernstein copulae. We extend previous statistical results regarding bivariate Bernstein copulae to the multivariate case and study their impact on multiple tests. In particular, we utilize them to derive asymptotic confidence regions for the family‐wise error rate (FWER) of multiple test procedures that are empirically calibrated by making use of Bernstein copulae approximations of the dependency structure among the test statistics. This extends a similar approach by Stange et al. (2015) in the parametric case. A simulation study quantifies the gain in FWER level exhaustion and, consequently, power that can be achieved by exploiting the dependencies, in comparison with common threshold calibrations like the Bonferroni or ?idák corrections. Finally, we demonstrate an application of the proposed methodology to real‐life data from insurance.     

Syntheses and structure–activity relationships for some triazolyl p38α MAPK inhibitors

The design, synthesis and biological evaluation of novel triazolyl p38α MAPK inhibitors with improved water solubility for formulation in cationic liposomes (SAINT-O-Somes) targeted at diseased endothelial cells is described. Water-solubilizing groups were introduced via a ‘click’ reaction of functional azides with 2-alkynyl imidazoles and isosteric oxazoles to generate two small libraries of 1,4-disubstituted 1,2,3-triazolyl p38α MAPK inhibitors. Triazoles with low IC₅₀ values and desired physicochemical properties were screened for in vitro downregulation of proinflammatory gene expression and were formulated in SAINT-O-Somes. Triazolyl p38α MAPK inhibitor 88 (IC₅₀ = 0.096 μM) displayed the most promising in vitro activity.     

Bcs1p can rescue a large and productive cytochrome bc1 complex assembly intermediate in the inner membrane of yeast mitochondria

The yeast cytochrome bc₁ complex, a component of the mitochondrial respiratory chain, is composed of ten distinct protein subunits. In the assembly of the bc₁ complex, some ancillary proteins, such as the chaperone Bcs1p, are actively involved. The deletion of the nuclear gene encoding this chaperone caused the arrest of the bc₁ assembly and the formation of a functionally inactive bc₁ core structure of about 500-kDa. This immature bc₁ core structure could represent, on the one hand, a true assembly intermediate or, on the other hand, a degradation product and/or an incorrect product of assembly. The experiments here reported show that the gradual expression of Bcs1p in the yeast strain lacking this protein was progressively able to rescue the bc₁ core structure leading to the formation of the functional homodimeric bc₁ complex. Following Bcs1p expression, the mature bc₁ complex was also progressively converted into two supercomplexes with the cytochrome c oxidase complex. The capability of restoring the bc₁ complex and the supercomplexes was also possessed by the mutated yeast R81C Bcsp1. Notably, in the human ortholog BCS1L, the corresponding point mutation (R45C) was instead the cause of a severe bc₁ complex deficiency. Differently from the yeast R81C Bcs1p, two other mutated Bcs1p's (K192P and F401I) were unable to recover the bc₁ core structure in yeast. This study identifies for the first time a productive assembly intermediate of the yeast bc₁ complex and gives new insights into the molecular mechanisms involved in the last steps of bc₁ assembly.     

Carbon and nitrogen isotope ratios in different compartments of a healthy and a declining Picea abies forest in the Fichtelgebirge,NE Bavaria

Summary Natural carbon and nitrogen isotope ratios were measured in different compartments (needles and twigs of different ages and crown positions, litter, understorey vegetation, roots and soils of different horizons) on 5 plots of a healthy and on 8 plots of a declining Norway spruce (Picea abies (L.) Karst.) forest in the Fichtelgebirge (NE Bavaria, Germany), which has recently been described in detail (Oren et al. 1988a; Schulze et al. 1989). The ¹³C values of needles did not differ between sites or change consistently with needle age, but did decrease from the sun-to the shade-crown. This result confirms earlier conclusions from gas exchange measurements that gaseous air pollutants did no long-lasting damage in an area where such damage was expected. Twigs (¹³C between-25.3 and-27.8) were significantly less depleted in ¹³C than needles (¹³C between-27.3 and-29.1), and ¹³C in twigs increased consistently with age. The ¹⁵N values of needles ranged between-2.5 and-4.1 and varied according to stand and age. In young needles ¹⁵N decreased with needle age, but remained constant or increased in needles that were 2 or 3 years old. Needles from the healthy site were more depleted in ¹⁵N than those from the declining site. The difference between sites was greater in old needles than in young ones. This differentiation presumably reflects an earlier onset of nitrogen reallocation in needles of the declining stand. ¹⁵N values in twigs were more negative than in needles (-3.5 to-5.2) and showed age- and stand-dependent trends that were similar to the needles. ¹⁵N values of roots and soil samples increased at both stands with soil depth from-3.5 in the organic layer to +4 in the mineral soil. The ¹⁵N values of roots from the mineral soil were different from those of twigs and needles. Roots from the shallower organic layer had values similar to twigs and needles. Thus, the bulk of the assimilated nitrogen was presumably taken up by the roots from the organic layer. The problem of separation of ammonium or nitrate use by roots from different soil horizons is discussed.     

Identification of NCF2/p67phox as a novel p53 target gene

Analysis of microarrays performed in p53-, TAp63α- and ΔNp63α-inducible SaOs-2 cell lines allowed the identification of NCF2 mRNA upregulation in response to p53 induction. NCF2 gene encodes for p67phox, the cytosolic subunit of the NADPH oxidase enzyme complex. The recruitment of p67phox to the cell membrane causes the activation of the NADPH oxidase complex followed by the generation of NADP+ and superoxide from molecular oxygen. The presence of three putative p53 binding sites on the NCF2 promoter was predicted, and the subsequent luciferase and chromatin immunoprecipitation assays showed the activation of NCF2 promoter by p53 and its direct binding in vivo to at least one of the sites, thus confirming the hypothesis. NCF2 upregulation was also confirmed by real-time PCR in several cell lines after p53 activation. NCF2 knockdown by siRNA results in a significant reduction of ROS production and stimulates cell death, suggesting a protective function of Nox2-generated ROS in cells against apoptosis. These results provide insight into the redox-sensitive signaling mechanism that mediates cell survival involving p53 and its novel target NCF2/p67phox.     

原位杂交检测lin-4 mRNA在Caenorhabditis elegans中的表达

lin-4是控制Caenorhabditis elegans(C.elegans)幼虫发育的异时性基因,也是一种小RNA分子(microRNA)。通过整体原位杂交检测小RNA lin-4在野生型和lin-14、lin-28突变体中的区域性表达,探讨lin-4在C.elegans发育时空控制中的作用。结果表明:lin-4 mRNA在胚胎发育的早期和中期表达,胚胎后期至L1期末没有表达,之后又持续表达,成虫中也可以检测到lin-4 mRNA的存在。在lin-14和lin-28突变体中,lin-4的表达基本与野生型一致,不受lin-14、lin-28基因突变的影响,说明lin-14和lin-28是lin-4的下游基因。     

Drosophila p24 homologues eclair and baiser are necessary for the activity of the maternally expressed Tkv receptor during early embryogenesis

p24 proteins are assumed to play an important role in the transport of secreted and transmembrane proteins into membranes. However, only few cargo proteins are known that partially, but in no case completely require p24 proteins for membrane transport. Here, we show that two p24 proteins are essential for dorsoventral patterning of Drosophila melanogaster embryo. Mutations in the genes, eclair (eca) and baiser (bai), encoding two p24 proteins reduce signalling by the TGF-beta homologue, Dpp, in early embryos. This effect is strictly maternal and specific to early embryogenesis, as Dpp signalling in other contexts is not notably affected. We provide genetic evidence that in the absence of eca or bai function in the oocyte, the maternally expressed type I TGF-beta receptor Tkv is not active. We propose that during early embryogenesis eca and bai are specifically required for the activity of the maternal Tkv, while the zygotic Tkv is not affected in the mutant embryos. Mutations in either eca or bai are sufficient for the depletion of Tkv activity and no enhancement of the phenotypes was observed in embryos derived from oocytes mutant for both genes. The dependence of maternal Tkv protein on the products of p24 genes may serve as an in vivo model for studying p24 proteins.     

Trisubstituted and tetrasubstituted pyrazolines as a novel class of cell-growth inhibitors in tumor cells with wild type p53

Derivatives with scaffolds of 1,3,5-tri-substituted pyrazoline and 1,3,4,5-tetra-substituted pyrazoline were synthesized and tested for their inhibitory effects versus the p53^+/+ HCT116 and p53^?/? H1299 human tumor cell lines. Several compounds were active against the two cell lines displaying IC₅₀ values in the low micromolar range with a clearly more pronounced effect on the p53^+/+ HCT116 cells. The compound class shows excellent developability due to the modular synthesis, allowing independent optimization of all three to four key substituents to improve the properties of the molecules.     

Analyses of chromosome copy number and expression level of four genes in the ciliate Chilodonella uncinata reveal a complex pattern that suggests epigenetic regulation

Exogenous wild-type p53 (wt-p53) tumor suppression increases the sensitivity of tumor cells to radiotherapy and chemotherapy. An iodized oil emulsion was used as a p53 vector for intra-arterial gene delivery to treat hepatic tumors. Whether the chemotherapeutic agent or the iodized oil affects exogenous wt-p53 activity remains poorly understood. In the present study, the early therapeutic response of rAd/p53, combined with 5-fluorouracil (5-FU) or with iodized oil, was observed in a human colon cancer model. Allograft models in 82 nude mice with human colon carcinoma SW480 were divided randomly into four groups and administered with physiologic saline, rAd/p53, rAd/p53+5-FU, and rAd/p53+iodized oil by intratumoral injection. At 24, 48, 72, 120, and 168 h after treatment, p53 expression, the Ki-67 index (KI), and the degree of tumor necrosis were assessed. The p53 expression and tumor necrosis in the therapeutic groups were higher than those in the control group. p53 expression reached its peak at 120 h in the rAd/p53 group, at 72 h in the rAd/p53+5-FU group, and at 48 h in the rAd/p53+iodized oil group. The p53 expression in the rAd/P53+5-FU group and the iodized oil group was significantly higher than those in the rAd/P53 group at 24 and 48 h. The results revealed that tumor necrosis is positively correlated with p53 expression. The KI of the rAd/p53+5-FU group increased significantly at 24 h. 5-FU and iodized oil increase the anticancer effect of rAd/p53, and 5-FU combined with rAd/p53 has a synergistic anticancer effect.