Characterization of centromere arrangements and test for random distribution in G0, G1, S,G2, G1, and early S′ phase in human lymphocytes

Summary The arrangement of centromeres, cluster formation and association with the nucleolus and the nuclear membrane were characterized in human lymphocytes during the course of interphase in a cell-phase-dependent manner. We evaluated 3 893 cell nuclei categorized by five parameters. The centromeres were visualized by means of indirect immunofluorescent labeling with anti-centromere antibodies (ACA) contained in serum of patients with CREST syndrome. The cell nuclei were classified as G₀, G₁, S, G₂, Gl₁ and early S phase by comparing microscopically identified groups of cell nuclei with flow cytometric determination of cell cycle stage of synchronized and unsynchronized lymphocyte cell cultures. Based on a discrimination analysis, a program was devised that calculated the probability for any cell nucleus belonging to the G₀, G₁, S, G₂, G₁ and early S phase using only two microscopic parameters. Various characteristics were determined in the G₀, S, and G₂ stages. A transition stage to S phase within G₁ was detected. This stage shows centromere arrangements not repeated in later cell cycles and which develop from the dissolution of centromere clusters in the periphery of the nucleus during G₀ and G₁. S phase exhibits various non-random centromere arrangements and associations of centromeres with the nucleolus. G₁ and early S phase of the second cell cycle display no characteristic centromere arrangement. The duplication of centromeres in G₂ is asynchronous in two phases. For all cell phases a test for random distribution of the centromeres in the cell nucleus was performed. There is a distinct tendency for centromeres to be in a peripheral position during Go and G₁; this tendency becomes weaker in S phase. Although the visual impression is a seemingly random distribution of centromeres in G₂ and G₁ statistical analysis still demonstrates a significant deviation from random distribution in favor of a peripheral location. Only the early S phase of the second cell cycle shows no significant deviation from a random distribution.     

Three new G6PD variants,G6PD Adana,G6PD Samandağ, and G6PD Balcali in Çukurova,Turkey

Summary Glucose-6-phosphate dehydrogenase (G6PD) enzyme from cases known to be completely or mildly deficient were analyzed. The enzymes were purified from blood samples by utilizing DEAE-52 cellulose pH 7.0 column chromatography and ammonium sulphate precipitation. Biochemical and electrophoretic properties of G6PD were studied in these partially purified enzymes. In this study wer report three new variants from Çukurova, named Adana, Samanda, and Balcali. Variant I (G6PD Adana) had a high K_m for G6P (210 M) and NADP (13M). Utilization of 2d-G6P was 38%. It had a slow electrophoretic mobility, a biphasic pH optimum curve, and abnormal heat stability. Variant II (G6PD Samanda) had a low K_m for G6P (25M) and a high K_m for NADP (18M). The rate of utilization of 2d-G6P was normal. G6PD Samanda deviated from the normal enzyme by its biphasic pH optimum curve and its slow electrophoretic mobility. Variant III (G6PD-Balcali) had a normal K_m G6P, NADP and rate of utilization of 2d-G6P. However, it showed a biphasic pH optimum curve and slow electrophoretic mobility.     

通光藤甙F,G,H和I结构

从通光藤(Marsdeniatenacissima)的茎中分离得到4个新的C21甾体甙———通光藤甙F(3),G(4),H(5)和I(6),以及2个已知化合物通光藤甙A(1)和B(2)。根据光谱数据和化学方法推定了其结构。同时,通过COLOC谱和二维核磁共振谱指定了这些化合物中甙元上11和12位的酯基确切连接位置。     

相思子根化学成分研究——相思子醌A,B,D,E,F,G

从民间药用抗肝炎药相思子（ＡｂｒｕｓｐｒｅｃａｔｏｒｉｕｓＬ．）根中分得８个异黄烷醌类化合物,即相思子醌Ａ、Ｂ、Ｄ、Ｅ、Ｆ、Ｇ以及已知化合物３,７二羟基６甲氧基双氢黄酮和２,８二羟基３,４,９,１０四甲氧基紫檀素。用化学转化和光谱学方法包括１Ｈ１ＨＣＯＳＹ、１Ｈ１３ＣＣＯＳＹ、ＣＤ等方法鉴定它们的结构。     

Paddyfield Warbler,Acrocephalus agricola,at Van Gölü, eastern Turkey

Abstract

A Paddyfield Warbler was mist-netted at Van in eastern Anatolia on 8.5 1987. This is the second record for Turkey.     

G��i and G�¦� Jointly Regulate the Conformations of a G�¦� Effector, the Neuronal G Protein-activated K+ Channel (GIRK)

Stable complexes among G proteins and effectors are an emerging concept in cell signaling. The prototypical Gβγ effector G protein-activated K⁺ channel (GIRK; Kir3) physically interacts with Gβγ but also with Gα_i/o. Whether and how Gα_i/o subunits regulate GIRK in vivo is unclear. We studied triple interactions among GIRK subunits 1 and 2, Gα_i3 and Gβγ. We used in vitro protein interaction assays and in vivo intramolecular Förster resonance energy transfer (i-FRET) between fluorophores attached to N and C termini of either GIRK1 or GIRK2 subunit. We demonstrate, for the first time, that Gβγ and Gα_i3 distinctly and interdependently alter the conformational states of the heterotetrameric GIRK1/2 channel. Biochemical experiments show that Gβγ greatly enhances the binding of GIRK1 subunit to Gα_i3^GDP and, unexpectedly, to Gα_i3^GTP. i-FRET showed that both Gα_i3 and Gβγ induced distinct conformational changes in GIRK1 and GIRK2. Moreover, GIRK1 and GIRK2 subunits assumed unique, distinct conformations when coexpressed with a “constitutively active” Gα_i3 mutant and Gβγ together. These conformations differ from those assumed by GIRK1 or GIRK2 after separate coexpression of either Gα_i3 or Gβγ. Both biochemical and i-FRET data suggest that GIRK acts as the nucleator of the GIRK-Gα-Gβγ signaling complex and mediates allosteric interactions between Gα_i^GTP and Gβγ. Our findings imply that Gα_i/o and the Gα_iβγ heterotrimer can regulate a Gβγ effector both before and after activation by neurotransmitters.     

Discriminations, reversals, and extra-dimensional shifts in the Göttingen minipig

G?ttingen minipigs were trained on a set-shifting procedure involving discriminations, reversals, and extra-dimensional shifts. The discriminations used were black-white discriminations and right-left discriminations. The initial visual and spatial discrimination seemed equally difficult, and only for the visual modality was reversal found to be more difficult than the initial discrimination. Visual reversal was more difficult than spatial reversal, and a larger number of perseverative sessions were found for visual reversal compared to spatial reversal. The acquisition of the extra-dimensional shift from the visual to the spatial dimension was not inferior to the learning of spatial reversal. Neither was the acquisition of the extra-dimensional shift from the spatial to the visual dimension inferior to the learning of visual reversal. Thus, no evidence was found for attention to stimulus dimensions in discrimination learning of the pigs.     

How does the G protein,Gi2, transduce mitogenic signals?

Serpentine receptors coupled to the heterotrimeric G protein, G_i2, are capable of stimulating DNA synthesis in a variety of cell types. A common feature of the G_i2-coupled stimulation of DNA synthesis is the activation of the mitogen-activated protein kinases (MAPKs). The regulation of MAPK activation by the G_i2-coupled thrombin and acetylcholine muscarinic M₂ receptors occurs by a sequential activation of a network of protein kinases. The MAPK kinase (MEK) which phosphorylates and activates MAPK is also activated by phosphorylation. MEK is phosphorylated and activated by either Raf or MEK kinase (MEKK). Thus, Raf and MEKK converge at MEK to regulate MAPK. G_i2-coupled receptors are capable of activating MEK and MAPK by Raf-dependent and Raf-independent mechanisms. Pertussis toxin catalyzed ADP-ribosylation of α_i2 inhibits both the Raf-dependent and-independent pathways activated by G_i2-coupled receptors. The Raf-dependent pathway involves Ras activation, while the Raf-independent activation of MEK and MAPK does not involve Ras. The Raf-independent activation of MEK and MAPK most likely involves the activation of MEKK. The vertebrate MEKK is homologous to the Ste11 and Byr2 protein kinases in the yeast Saccharomyces cerevisiae and Schizosaccharomyces pombe, respectively. The yeast Ste11 and Byr2 protein kinases are involved in signal transduction cascades initiated by pheromone receptors having a 7 membrane spanning serpentine structure coupled to G proteins. MEKK appears to be conserved in the regulation of G protein-coupled signal pathways in yeast and vertebrates. Raf represents a divergence in vertebrates from the yeast pheromone-responsive protein kinase system. Defining MEKK and Raf as a divergence in the MAPK regulatory network provides a mechanism for differential regulation of this system by G_i2-coupled receptors as well as other receptor systems, including the tyrosine kinases.     

Gαq,Gγ1 and Plc21C Control Drosophila Body Fat Storage

mobilization of body fat is essential for energy homeostasis in animals. In insects, the adipokinetic hormone （Akh） systemically controls body fat mobilization. Biochemical evidence supports that Akh signals via a G protein-coupled receptor （GPCR） called Akh receptor （AkhR） using cyclic-AMP （cAMP） and Ca2＋ second messengers to induce storage lipid release from fat body cells. Recently, we provided genetic evidence that the intracellular calcium （iCa2＋） level in fat storage cells controls adiposity in the fruit fly Drosophila melanogaster. However, little is known about the genes, which mediate Akh signalling downstream of the AkhR to regulate changes in iCa2＋. Here, we used thermogenetics to provide in vivo evidence that the GPCR signal transducers G protein α q subunit （Gαq）, G protein γ1 （Gγ1） and Phospholipase C at 21C （Plc21C） control cellular and organismal fat storage in Drosophila. Transgenic modulation of Gαq, Gγ1 and Plc21C affected the iCa2＋ of fat body cells and the expression profile of the lipid metabolism effector genes midway and brummer, which results in severely obese or lean flies. Moreover, functional impairment of Gαq, Gγ1 and Plc21C antagonised Akh-induced fat depletion. This study characterizes Gαq, Gγ1 and Plc21C as anti-obesity genes and supports the model that Akh employs the Gαq/Gγ1/Plc21C module of iCa2＋ control to regulate lipid mobilization in adult Drosophila.     

Myrmechis bakhimensis D. Maity, N. Pradhan ＆ G. G. Maiti, a new species of Orchidaceae from Sikkim Himalaya

Myrmechis bakhimensis D. Maity,N. Pradhan & G. G. Maiti (Orchidaceae),a new species from Sikkim Himalaya,is described and illustrated. The new species most closely resembles M. japonica (Reichb.) Rolfe and M. chinensis Rolfe with similar shape and size of lamina and the “T”-shaped epichile,but differs by the perfectly glabrous and eciliate floral bract,5-nerved dorsal sepal,and emarginate,mucronate epichile.     

Identification of three novel mutations (457 TAT→G,D192G,Q685X) in the Slovenian CF patients

Chromosomes from a cohort of 60 Slovenian families, corresponding to the 121 cystic fibrosis (CF) chromosomes available, were fully scanned for mutations in the coding sequence of the cystic fibrosis transmembrane conductance regulator (CFTR) gene (The 60 families yielded 121 CF alleles because the mother of one patient was also affected). This corresponds to the 27 exons and intron/exon boundaries that have been studied in chromosomes carrying unidentified alleles. As a result of this survey 84% of the alleles are now clearly identified and we describe in this paper three novel mutations (457 TATG, D192G, and Q685X).     

Gαo and Gαq)regulate the expression of daf-7, a TGFβ-like gene, in Caenorhabditis elegans

Caenorhabditis elegans enter an alternate developmental stage called dauer in unfavorable conditions such as starvation, overcrowding, or high temperature. Several evolutionarily conserved signaling pathways control dauer formation. DAF-7/TGFβ and serotonin, important ligands in these signaling pathways, affect not only dauer formation, but also the expression of one another. The heterotrimeric G proteins GOA-1 (Gα(o)) and EGL-30 (Gα(q)) mediate serotonin signaling as well as serotonin biosynthesis in C. elegans. It is not known whether GOA-1 or EGL-30 also affect dauer formation and/or daf-7 expression, which are both modulated in part by serotonin. The purpose of this study is to better understand the relationship between proteins important for neuronal signaling and developmental plasticity in both C. elegans and humans. Using promoter-GFP transgenic worms, it was determined that both goa-1 and egl-30 regulate daf-7 expression during larval development. In addition, the normal daf-7 response to high temperature or starvation was altered in goa-1 and egl-30 mutants. Despite the effect of goa-1 and egl-30 mutations on daf-7 expression in various environmental conditions, there was no effect of the mutations on dauer formation. This paper provides evidence that while goa-1 and egl-30 are important for normal daf-7 expression, mutations in these genes are not sufficient to disrupt dauer formation.     

Association between tumor necrosis factor-α promoter −308 A/G, −238 A/G, interleukin-6 −174 G/C and −572 G/C polymorphisms and periodontal disease: a meta-analysis

The aim of this study was to determine whether tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) promoter polymorphisms confer susceptibility to periodontitis in ethnically different populations. A literature search was performed using PubMed and Embase and a meta-analysis of the identified studies was conducted to explore the associations between TNF-α ?308 A/G, ?238 A/G, IL-6 promoter ?174 G/C and ?572 G/C polymorphisms and periodontitis. Seventeen comparison studies for the TNF-α ?308 A/G polymorphism and three studies for the TNF-α ?238 A/G polymorphism were included in the meta-analysis. And 16 separate studies for the IL-6 ?174 G/C polymorphism and 10 studies for the IL-6 ?572 G/C polymorphism were considered in our meta-analysis. Analysis after stratification by ethnicity indicated that the TNF-α ?308 A allele was associated with periodontitis in Brazilian, Asian, and Turkish populations (OR = 0.637, 95 % CI = 0.447–0.907, p = 0.013; OR = 0.403, 95 % CI = 0.204–0.707, p = 0.009; OR = 1.818, 95;  % CI = 1.036–3.189, p = 0.037). The meta-analysis showed no association between the TNF-α ?238 A/G polymorphism and periodontitis. The meta-analysis indicated an association of the IL-6 ?174 G/C polymorphisms with periodontitis in Brazilian populations (OR for GG + GC = 2.394, 95 % CI = 1.081–5.302, p = 0.031). Stratification by ethnicity and disease type indicated an association between the IL-6 ?572 G allele and chronic periodontitis (OR = 1.585, 95 % CI = 1.030–2.439, p = 0.036), and periodontitis in Europeans (OR = 2.118, 95 % CI = 1.254–3.577, p = 0.005). This meta-analysis demonstrates that the TNF-α ?308 A/G polymorphism confers susceptibility to periodontitis in Brazilian, Asian and Turkish populations. The IL-6 ?174 G/C polymorphism may confer susceptibility to periodontitis in Brazilians, and the IL-6 ?572 G/C polymorphism may be associated with susceptibility to periodontitis in Europeans, and chronic periodontitis.