Accumulation of galloyl derivatives in a green alga, Spirogyra varians, in response to cold stress

The green alga Spirogyra varians accumulated antioxidative compounds in response to cold stress. When the algae were transferred from 20°C to 4°C, the amount of phenolic contents and flavonoids in the cell increased 17 times and 30 times, respectively, in 2 months. At this time, the radical scavenging activity of the methanolic extract of S. varians was 238 times higher than that of initial culture. To identify the responsible antioxidants, the methanolic extract was obtained from the algae grown at 4°C. HPLC analysis of the extract showed six compounds newly produced or increased over time. Four of the compounds were successfully purified, and the structures were identified using ¹H NMR spectroscopy. The compounds were galloyl derivatives—methyl gallate, 1-O-Galloyl-β-d-glucose, 1,2,3,6-tetra-O-Galloyl-β-d-glucose and 1,2,3,4,6-penta-O-Galloyl-β-d-glucose which are intermediates of the shikimate pathway.     

Selenium promotes proliferation of chondrogenic cell ATDC5 by increment of intracellular ATP content under serum deprivation

Selenium (Se) is an essential micronutrient, and low Se intake in Se‐deficient areas plays roles in an endemic osteochondropathy characterized by chondronecrosis in growth plate and articular cartilage. However, the biological activities of Se on cartilage are largely unknown. In this study, we examined the effects of Se on chondrogenic cell ATDC5 and the possible mechanisms involved. We demonstrated that Se stimulated ATDC5 cell proliferation under serum deprivation but not routine culture. Furthermore, Se promoted G1‐phase cell cycle progression along with induction of cyclin D1 expression at the mRNA and protein level. Moreover, Se increased intracellular ATP content and decreased intracellular superoxide anion concentration without affecting intracellular redox status as estimated by ratio of the reduced and oxidized glutathione. In addition, suppression of intracellular ATP synthesis by glycolysis inhibitor or mitochondrial uncoupler both abrogated Se‐mediated cyclin D1 induction. These findings suggest Se stimulates proliferation of chondrogenic cell ATDC5 through acceleration of cell cycle progression accompanied with cyclin D1 induction by enhancement of intracellular ATP content. This novel finding provides evidence for a role of Se in cartilage formation and degenerative processes and further supports the relationship between Se status and cartilage function that may lead to better utilization of Se for cartilage homeostasis. Copyright © 2012 John Wiley & Sons, Ltd.     

Macrophage-stimulated cardiac fibroblast production of IL-6 is essential for TGF β/Smad activation and cardiac fibrosis induced by angiotensin II

Interleukin-6 (IL-6) is an important cytokine participating in multiple biologic activities in immune regulation and inflammation. IL-6 has been associated with cardiovascular remodeling. However, the mechanism of IL-6 in hypertensive cardiac fibrosis is still unclear. Angiotensin II (Ang II) infusion in mice increased IL-6 expression in the heart. IL-6 knockout (IL-6-/-) reduced Ang II-induced cardiac fibrosis: 1) Masson trichrome staining showed that Ang II infusion significantly increased fibrotic areas of the wild-type mouse heart, which was greatly suppressed in IL-6-/- mice and 2) immunohistochemistry staining showed decreased expression of α-smooth muscle actin (α-SMA), transforming growth factor β1 (TGF-β1) and collagen I in IL-6-/- mouse heart. The baseline mRNA expression of IL-6 in cardiac fibroblasts was low and was absent in cardiomyocytes or macrophages; however, co-culture of cardiac fibroblasts with macrophages significantly increased IL-6 production and expression of α-SMA and collagen I in fibroblasts. Moreover, TGF-β1 expression and phosphorylation of TGF-β downstream signal Smad3 was stimulated by co-culture of macrophages with cardiac fibroblasts, while IL-6 neutralizing antibody decreased TGF-β1 expression and Smad3 phosphorylation in co-culture of macrophage and fibroblast. Taken together, our results indicate that macrophages stimulate cardiac fibroblasts to produce IL-6, which leads to TGF-β1 production and Smad3 phosphorylation in cardiac fibroblasts and thus stimulates cardiac fibrosis.     

β,β-Dimethylacrylshikonin Induces Mitochondria Dependent Apoptosis through ERK Pathway in Human Gastric Cancer SGC-7901 Cells

β,β-Dimethylacrylshikonin, one of the active components in the root extracts of Lithospermum erythrorhizon, posses antitumor activity. In this study, we discussed the molecular mechanisms of β,β-dimethylacrylshikonin in the apoptosis of SGC-7901 cells. β,β-Dimethylacrylshikonin reduced the cell viability of SGC-7901 cells in a dose- and time-dependent manner and induced cell apoptosis. β,β-Dimethylacrylshikonin treatment in SGC-7901 cells down-regulated the expression of XIAP, cIAP-2, and Bcl-2 and up-regulated the expression of Bak and Bax and caused the loss of mitochondrial membrane potential and release of cytochrome c. Additionally, β,β-dimethylacrylshikonin treatment led to activation of caspases-9, 8 and 3, and cleavage of poly (ADP-ribose) polymerase (PARP), which was abolished by pretreatment with the pan-caspase inhibitor Z-VAD-FMK. β,β-Dimethylacrylshikonin induced phosphorylation of extracellular signal-regulated kinase (ERK) in SGC-7901 cells. U0126, a specific MEK inhibitor, blocked the ERK activation by β,β-dimethylacrylshikonin and abrogated β,β-dimethylacrylshikonin -induced apoptosis. Our results demonstrated that β,β-dimethylacrylshikonin inhibited growth of gastric cancer SGC-7901 cells by inducing ERK signaling pathway, and provided a clue for preclinical and clinical evaluation of β,β-dimethylacrylshikonin for gastric cancer therapy.     

一株产丙烯腈水合酶菌株的研究

从山东省泰山地区土壤中分离到一株能产生丙烯腈水合酶的微生物菌株８６－１６３,经分类学特征鉴定可归属于诺卡氏菌属,其培养特征、生理生化特征及产酶活性等方面与已报导的诺卡氏菌有差别,暂定名为Ｎｏｃａｒｄｉａｓｐ．８６－１６３。     

Leukotactin-1-induced ERK activation is mediated via Gi/Go protein/PLC/PKC delta/Ras cascades in HOS cells

Recently cloned leukotactin-1 (Lkn-1) that belongs to CC chemokine family has not been characterized. To understand the intracellular events following Lkn-1 binding to CCR1, we investigated the activities of signaling molecules in response to Lkn-1 in human osteogenic sarcoma cells expressing CCR1. Lkn-1-stimulated cells showed elevated phosphorylation of extracellular signal-related kinases (ERK1/2) with a distinct time course. ERK activation was peaked in 30 min and 12 h showing biphasic activation of ERK. Pertussis toxin, an inhibitor of G(i)/G(o) protein, and phospholipase C (PLC) inhibitor blocked Lkn-1-induced activation of ERK. Protein kinase C delta (PKC delta) specific inhibitor rottlerin inhibited ERK activation in Lkn-1-stimulated cells. The activities of PLC and PKC delta were also enhanced by Lkn-1 stimulation. Dominant negative Ras inhibited activation of ERK. Immediate early response genes such as c-fos and c-myc were induced by Lkn-1 stimulation. Lkn-1 affected the cell cycle progression by cyclin D(3) induction. These results suggest that Lkn-1 activates the ERK pathway by transducing the signal through G(i)/G(o) protein, PLC, PKC delta and Ras, and it may play a role for cell proliferation, differentiation, and regulation of gene expression for other cellular processes.     

Therapeutic benefits of CD90‐negative cardiac stromal cells in rats with a 30‐day chronic infarct

Cardiac stromal cells (CSCs) can be derived from explant cultures, and a subgroup of these cells is viewed as cardiac mesenchymal stem cells due to their expression of CD90. Here, we sought to determine the therapeutic potential of CD90‐positive and CD90‐negative CSCs in a rat model of chronic myocardial infarction. We obtain CD90‐positive and CD90‐negative fractions of CSCs from rat myocardial tissue explant cultures by magnetically activated cell sorting. In vitro, CD90‐negative CSCs outperform CD90‐positive CSCs in tube formation and cardiomyocyte functional assays. In rats with a 30‐day infarct, injection of CD90‐negative CSCs augments cardiac function in the infarct in a way superior to that from CD90‐positive CSCs and unsorted CSCs. Histological analysis revealed that CD90‐negative CSCs increase vascularization in the infarct. Our results suggest that CD90‐negative CSCs could be a development candidate as a new cell therapy product for chronic myocardial infarction.     

Embryological Studies in Glycyrrhiza uralensis Fisch.

This paper reports the studies of overall embryology of Glycyrrhiza uralensis Fisch. Development of the anther wall follows the dicotyledonous type. The cytokinesis of the microspore mother cell in meiosis is of simultaneous type. The arrangement of microspores in tetrad is tetrahedral, isobilateral and decussate. Microspores have various types of abortive to development. Mature pollen grain is of the 2-celled type. The ovule is bitegminous, crassinucellate and campylotropous. The megaspore mother cell gives rise to unequal dyad and then linear tetrad. The chalazal megaspore, the second or the third megaspore towards the micropylar end are functional megaspore. The development of the embryo sac conforms to the Polygonum type. Mature embryo sac has various types of variation. The fertilization belongs to the premitotic type of syngamy. The development of most embryoes belongs to the Onagrad type. The development of the endosperm belongs to the nuclear type and the endosperm near the chalazal end develops into haustorium.     

Autophagy Enhances Bacterial Clearance during P. aeruginosa Lung Infection

Pseudomonas aeruginosa is an opportunistic bacterial pathogen which is the leading cause of morbidity and mortality among cystic fibrosis patients. Although P. aeruginosa is primarily considered an extacellular pathogen, recent reports have demonstrated that throughout the course of infection the bacterium acquires the ability to enter and reside within host cells. Normally intracellular pathogens are cleared through a process called autophagy which sequesters and degrades portions of the cytosol, including invading bacteria. However the role of autophagy in host defense against P. aeruginosa in vivo remains unknown. Understanding the role of autophagy during P. aeruginosa infection is of particular importance as mutations leading to cystic fibrosis have recently been shown to cause a blockade in the autophagy pathway, which could increase susceptibility to infection. Here we demonstrate that P. aeruginosa induces autophagy in mast cells, which have been recognized as sentinels in the host defense against bacterial infection. We further demonstrate that inhibition of autophagy through pharmacological means or protein knockdown inhibits clearance of intracellular P. aeruginosa in vitro, while pharmacologic induction of autophagy significantly increased bacterial clearance. Finally we find that pharmacological manipulation of autophagy in vivo effectively regulates bacterial clearance of P. aeruginosa from the lung. Together our results demonstrate that autophagy is required for an effective immune response against P. aeruginosa infection in vivo, and suggest that pharmacological interventions targeting the autophagy pathway could have considerable therapeutic potential in the treatment of P. aeruginosa lung infection.     

An-1 Encodes a Basic Helix-Loop-Helix Protein That Regulates Awn Development,Grain Size,and Grain Number in Rice

Long awns are important for seed dispersal in wild rice (Oryza rufipogon), but are absent in cultivated rice (Oryza sativa). The genetic mechanism involved in loss-of-awn in cultivated rice remains unknown. We report here the molecular cloning of a major quantitative trait locus, An-1, which regulates long awn formation in O. rufipogon. An-1 encodes a basic helix-loop-helix protein, which regulates cell division. The nearly-isogenic line (NIL-An-1) carrying a wild allele An-1 in the genetic background of the awnless indica Guangluai4 produces long awns and longer grains, but significantly fewer grains per panicle compared with Guangluai4. Transgenic studies confirmed that An-1 positively regulates awn elongation, but negatively regulates grain number per panicle. Genetic variations in the An-1 locus were found to be associated with awn loss in cultivated rice. Population genetic analysis of wild and cultivated rice showed a significant reduction in nucleotide diversity of the An-1 locus in rice cultivars, suggesting that the An-1 locus was a major target for artificial selection. Thus, we propose that awn loss was favored and strongly selected by humans, as genetic variations at the An-1 locus that cause awn loss would increase grain numbers and subsequently improve grain yield in cultivated rice.