Acylated ghrelin secretion is acutely suppressed by oral glucose load or insulin-induced hypoglycemia independently of basal growth hormone secretion in humans

BACKGROUND: Ghrelin has been reported to be the natural ligand of growth hormone (GH) secretagogue receptor, and it is known that exogenous ghrelin administration strongly stimulates GH release in humans. However, the effects of endogenous ghrelin on GH secretion and changes in ghrelin levels during dynamic changes in GH levels are not well understood. METHODS: Therefore, we measured circulating acylated ghrelin concentrations during oral glucose tolerance tests (OGTTs) in patients with active acromegaly (AA, n = 9) and in age/sex/BMI-matched group A controls (n = 12), and during insulin tolerance testing (ITT) in patients with GH deficiency (GHD, n = 10) and in group B controls (n = 10). Plasma acylated ghrelin, serum GH, insulin and glucose levels were measured during each test. RESULTS: Fasting plasma ghrelin levels correlated negatively with serum insulin levels in both group A and B controls (r = -0.665; p < 0.05) but not in patients with AA or GHD. During OGTTs, circulating ghrelin levels decreased significantly with a nadir at 30 min in both patients with AA (p < 0.05) and group A controls (p < 0.01). Also, ITTs were followed by a significant decrease in circulating ghrelin levels with a nadir at 30 min in patients with GHD (p < 0.05) and in group B controls (p < 0.05). CONCLUSION: The results of the study show that at baseline acylated ghrelin levels do not differ with respect to the GH status (GH excess or GH deficiency) and, furthermore, the suppression of acylated ghrelin levels during OGTT or ITT is independent of the GH response to the tests.     

PlantGI: a database for searching gene indices in agricultural plants developed at NIAB, Korea

The Plant Gene Index (PlantGI) database is developed as a web-based search system with search capabilities for keywords to provide information on gene indices specifically for agricultural plants. The database contains specific Gene Index information for ten agricultural species, namely, rice, Chinese cabbage, wheat, maize, soybean, barley, mushroom, Arabidopsis, hot pepper and tomato. PlantGI differs from other Gene Index databases in being specific to agricultural plant species and thus complements services from similar other developments. The database includes options for interactive mining of EST CONTIGS and assembled EST data for user specific keyword queries. The current version of PlantGI contains a total of 34,000 EST CONTIGS data for rice (8488 records), wheat (8560 records), maize (4570 records), soybean (3726 records), barley (3417 records), Chinese cabbage (3602 records), tomato (1236 records), hot pepper (998 records), mushroom (130 records) and Arabidopsis (8 records). AVAILABILITY: The database is available for free at http://www.niab.go.kr/nabic/.     

Identification of Tuberculosis Susceptibility Genes with Human Macrophage Gene Expression Profiles

Although host genetics influences susceptibility to tuberculosis (TB), few genes determining disease outcome have been identified. We hypothesized that macrophages from individuals with different clinical manifestations of Mycobacterium tuberculosis (Mtb) infection would have distinct gene expression profiles and that polymorphisms in these genes may also be associated with susceptibility to TB. We measured gene expression levels of >38,500 genes from ex vivo Mtb-stimulated macrophages in 12 subjects with 3 clinical phenotypes: latent, pulmonary, and meningeal TB (n = 4 per group). After identifying differentially expressed genes, we confirmed these results in 34 additional subjects by real-time PCR. We also used a case-control study design to examine whether polymorphisms in differentially regulated genes were associated with susceptibility to these different clinical forms of TB. We compared gene expression profiles in Mtb-stimulated and unstimulated macrophages and identified 1,608 and 199 genes that were differentially expressed by >2- and >5-fold, respectively. In an independent sample set of 34 individuals and a subset of highly regulated genes, 90% of the microarray results were confirmed by RT-PCR, including expression levels of CCL1, which distinguished the 3 clinical groups. Furthermore, 6 single nucleotide polymorphisms (SNPs) in CCL1 were found to be associated with TB in a case-control genetic association study with 273 TB cases and 188 controls. To our knowledge, this is the first identification of CCL1 as a gene involved in host susceptibility to TB and the first study to combine microarray and DNA polymorphism studies to identify genes associated with TB susceptibility. These results suggest that genome-wide studies can provide an unbiased method to identify critical macrophage response genes that are associated with different clinical outcomes and that variation in innate immune response genes regulate susceptibility to TB.     

Intraspecific variation of cuticular hydrocarbon profiles in the Anastrepha fraterculus (Diptera: Tephritidae) species complex

The goal of this study was to define whether cuticular hydrocarbons (CHs) could be used for taxonomic determination of putative species hidden in the Anastrepha fraterculus cryptic species complex, widespread from Argentina to Mexico. Recently, increasing evidence of phenotypic and genetic variability has resulted in the characterization of eight morphotypes within this complex. The CH profiles of six A. fraterculus populations from Argentina, Brazil, Peru, Colombia and Mexico were analysed in this study by two‐dimensional gas chromatography coupled with mass spectrometry. In parallel, multiple factorial analyses were used to elucidate population structures. Vector populations segregated into four distinct groups. The analysis demonstrated that the studied populations from Peru, Argentina and southern Brazil (Vacaria) might be classified in accordance with the earlier division of the A. fraterculus complex into Peruvian, and Brazilian‐1 cryptic species, using the specific CH profiles. Population from south‐eastern Brazil (Piracicaba) formed separated group. Mexican and Andean (Colombian) putative species had similar CH signatures, when compared to each other.     

Valproic acid promotes differentiation of hepatocyte-like cells from whole human umbilical cord-derived mesenchymal stem cells

Mesenchymal stem cells (MSCs) are mesoderm-derived cells that are considered a good source of somatic cells for treatment of many degenerative diseases. Previous studies have reported the differentiation of mesodermal MSCs into endodermal and ectodermal cell types beyond their embryonic lineages, including hepatocytes and neurons. However, the molecular pathways responsible for the direct or indirect cell type conversion and the functional ability of the differentiated cells remain unclear and need further research. In the present study, we demonstrated that valproic acid (VPA), which is a histone deacetylase inhibitor, induced an increase in the expression of endodermal genes including CXCR4, SOX17, FOXA1, FOXA2, GSC, c-MET, EOMES, and HNF-1β in human umbilical cord derived MSCs (hUCMSCs). In addition, we found that VPA is able to increase these endodermal genes in hUCMSCs by activating signal transduction of AKT and ERK. VPA pretreatment increased hepatic differentiation at the expense of adipogenic differentiation. The effects of VPA on modulating hUCMSCs fate were diminished by blocking AKT and ERK activation using specific signaling inhibitors. Together, our results suggest that VPA contributes to the lineage conversion of hUCMSCs to hepatic cell fate by upregulating the expression of endodermal genes through AKT and ERK activation.     

MicroRNA-27 promotes the differentiation of odontoblastic cell by targeting APC and activating Wnt/β-catenin signaling

MicroRNAs (miRNAs) play an essential role in regulating cell differentiation either by inhibiting mRNA translation or by inducing its degradation. However, the role of miRNAs in odontoblastic cell differentaion is largely unknown. In the present study, we demonstrate that the expression of miR-27 was significantly increased during MDPC-23 odontoblastic cell differentiation. Furthermore, the up-regulation of miR-27 promotes the differentiation of MDPC-23 odontoblastic cells and accelerates mineralization without cell proliferation. In addition, our results of target gene prediction revealed that the mRNA of adenomatous polyposis coli (APC) associated with Wnt/β-catenin signaling pathway has miR-27 binding site in the its 3′ UTR and is suppressed by miR-27. Subsequentially, the down-regulated APC by miR-27 triggered the activation of Wnt/β-catenin signaling through accumulation of β-catenin in the nucleus. Our data suggest that miR-27 promotes MDPC-23 odontoblastic cell differentiation by targeting APC and activating Wnt/β-catenin signaling. Therefore, miR-27 might be considered a critical candidate as an odontoblastic differentiation molecular target for the development of miRNA based therapeutic agents in the dental medicine.     

Requirement of the expression of 3-phosphoglycerate dehydrogenase for traversing S phase in murine T lymphocytes following immobilized anti-CD3 activation

Murine resting (G₀) T lymphocytes contained no detectable mRNA of 3-phosphoglycerate dehydrogenase (PHGDH) catalyzing the first step in the phosphorylated pathway of l-serine biosynthesis. Immobilized anti-CD3 activation of G₀ T cells expressed the PHGDH mRNA in G₁ with a maximum level in S phase. G₀ T cells activated with either immobilized anti-CD3 plus CsA or PBu₂, which failed to drive the activated T cells to enter S phase, did not express the PHGDH mRNA unless exogenous rIL-2 was added. Blocking of IL-2R signaling by adding anti-IL-2 and anti-IL-2Rα resulted in no expression of the PHGDH mRNA during immobilized anti-CD3 activation of G₀ T cells. Deprivation of l-serine from culture medium or addition of antisense PHGDH oligonucleotide significantly reduced [³H]TdR incorporation of activated T cells. These results indicate that the PHGDH gene expression, dictated by IL-2R signaling, is a crucial event for DNA synthesis during S phase of activated T cells.     

The effects of p38 gene silencing on breast cancer cells

p38 mitogen-activated protein kinases (MAPK) are members of the MAPK family that are activated by inflammatory cytokines and a variety of environmental stresses. It mediates various biological processes. p38 MAPK activity play important roles in tumour progression. Excessive p38 expression is observed in invasive breast cancers. The aim of the present study was to investigate whether the p38 siRNA transfection of breast cancer cells is a putative preventive treatment for human breast cancer. p38 siRNA was used at a concentration of 15, 30, and 100 nM in human breast cancer cell lines (MCF-7) and normal fibroblast cell lines (NIH 3T3). After 48 and 72 h of transfection, the reduction in p38 expression was measured using quantitative real-time PCR. The activation of p38 signalling was measured by ELISA. XTT cell proliferation assay was performed to determine the effect of p38 silencing on MCF-7 and NIH 3T3 cell lines. The results demonstrated that approximately 96 % gene silencing occurred by the selected siRNA targeting p38 mRNA. The most effective silencing was observed at 72 h post-transfection using 30 nM p38 siRNA. The results of ELISA showed that the expression of p38 protein was inhibited by p38 siRNA at 30 nM siRNA and 100 nM at 72 h post transfection. XTT results showed that cells stimulated by 30 nM siRNA at 72 h post transfection were the lowest in proliferation. p38 siRNA can interfere with the expression of p38 at protein level in MCF-7 cells, result in inhibition of cell proliferation. p38 siRNA may be a critical regulator to promote the proliferation and protein expression in MCF-7 cells. In this study, we demonstrate that p38 silencing is a preventive maintenance for treating breast cancer.     

Salt tolerance in <Emphasis Type="Italic">Solanum pennellii</Emphasis>: antioxidant response and related QTL

Background  

Excessive soil salinity is an important problem for agriculture, however, salt tolerance is a complex trait that is not easily bred into plants. Exposure of cultivated tomato to salt stress has been reported to result in increased antioxidant content and activity. Salt tolerance of the related wild species, Solanum pennellii, has also been associated with similar changes in antioxidants. In this work, S. lycopersicum M82, S. pennellii LA716 and a S. pennellii introgression line (IL) population were evaluated for growth and their levels of antioxidant activity (total water-soluble antioxidant activity), major antioxidant compounds (phenolic and flavonoid contents) and antioxidant enzyme activities (superoxide dismutase, catalase, ascorbate peroxidase and peroxidase) under both control and salt stress (150 mM NaCl) conditions. These data were then used to identify quantitative trait loci (QTL) responsible for controlling the antioxidant parameters under both stress and nonstress conditions.     

The anatomical and micromorphological characteristics of <Emphasis Type="Italic">Salvia vermifolia</Emphasis> (Section <Emphasis Type="Italic">Aethiopis</Emphasis> Bentham,Lamiaceae) from Central Anatolia,Turkey

The gross anatomical features, namely stem, blade and petiole and the micromorphological features, trichome, pollen and nutlet of Salvia vermifolia Hedge & Hub.-Mor. (Sect. Aethiopis Bentham, Lamiaceae) were examined using light microscopy (LM) and scanning electron microscopy (SEM). S. vermifolia is a perennial endemic herb growing on igneous and serpentine slopes in Sivas province, Central Anatolia, Turkey. The results obtained from anatomical studies show that the stem is made up of 4–8-layers of collenchyma cells and 1-3-layers chlorenchyma cells. The blade is amphistomatic, bifacial, with 2-3-layered palisade cells on the adaxial. The petiole has three large central bundles and six small subsidiary bundles. Peltate glandular, capitate glandular and non-glandular trichomes are present in S. vermifolia. The peltate glandular trichomes are present in abundance on the calyx and corolla, and capitate glandular trichomes are predominant on the calyx, inflorescence axis, pedicel and stem. The acicular non-glandular trichomes are mainly situated on the calyx, corolla, inflorescence axis and pedicels whereas the floccose non-glandular trichomes are common on both sides of the leaf, inflorescence axis and petiole. The pollen grains are hexacolpate to octacolpate, medium to large (P, polar axis=45.29–62.49 μm; E, equatorial axis=45.32-62.38 μm), oblate-spheroidal to prolate-spheroidal (P/E=0.91–1.02) and their exine ornamentation is bireticulate. The nutlets are 2.70–2.90 mm long and 1.90–2.13 mm wide, brown, ovoid-oblong in their outline, rounded-trigonous in transverse section, and their surface is glabrous and colliculate.