Alanine:glyoxylate aminotransferase activities in liver of Suncus murinus (insectivora)

1. The distribution of L-alanine:glyoxylate aminotransferase (AGT) activities were found in Suncus liver, 55% in particulate fraction and 45% in supernatant. 2. 65% of AGT activities in particulate were dependent on AGT isoenzyme 2 (AGT 2) having molecular weight 210,000, the remainder (35%) of AGT activities were dependent on AGT isoenzyme 1 (AGT 1) which have aminotransferase activity for serine. AGT activities in supernatant were dependent on AGT 1, AGT 2 and alanine:2-oxoglutarate aminotransferase (GPT), and their activity ratios were 10, 15 and 75%, respectively. 3. Km values for alanine were 0.52 mM; AGT 1, 3.3 mM; AGT 2, 0.88 mM; GPT measuring with AGT activity. AGT activity of GPT was inhibited by addition of glutamate and its Ki value was 1.8 mM. 4. Some other properties of AGT 1, AGT 2 and GPT are described.     

Structure-activity relations of azafluorenone and azaanthraquinone as antimicrobial compounds

Antimicrobial activities of two azafluorenones, four 1-azaanthraquinones, five 2-azaanthraquinones, and one 2-azaquinone were tested. Several azaanthraquinones possessed broad, potent activity, while the azafluorenones demonstrated weak activity. The following structure-activity relationship was postulated: (1) activity decreased in the order 2-azaanthraquinones>1-azaanthraquinones>azafluorenones; and (2) a hydroxyl group at the peri-carbonyl group enhanced activity. In addition, correlations among reduction potential, hydrophobic parameter, and antimicrobial activity were discussed.     

猪粪和土霉素对不同肥力土壤微生物数量及活性的影响

在不施肥和施用猪粪两种情况下,采用培养试验研究了不同浓度土霉素污染(0、0.1、1、10、100和1000 mg·kg^-1)对土壤细菌丰度、酶活性和NO₃-N浓度等的影响.试验培养温度为25 ℃,培养时间为30 d,取样分析时间分别为1、4和30 d.结果表明：在不施肥条件下,土霉素污染对土壤细菌数量及微生物活性的影响较小,土壤S₁、S₂和S₃细菌数量、呼吸强度、酶活性和NO₃-N浓度下降10%时土霉素的剂量（EC₁₀）分别为36～1000 mg·kg^-1、20～1000 mg·kg^-1和4～1000 mg·kg^-1;而在施用猪粪的情况下,对应的数值分别为2～656 mg·kg^-1、2～81 mg·kg^-1和1～42 mg·kg^-1.添加土霉素对土壤细菌及酶活性的影响随土壤肥力的提高而增大,且其对土壤细菌数量和呼吸强度的影响大于对酶活性和NO₃-N浓度的影响.土霉素污染对土壤微生物数量和活性的影响随时间变化而变化,一般在培养4 d时的影响最为明显.土霉素对土壤微生物的影响总体上表现为抑制作用.     

Synthesis and biological activity of optically active NCL-1, a lysine-specific demethylase 1 selective inhibitor

Optically active (1S,2R)-NCL-1 and (1R,2S)-NCL-1 were synthesized and evaluated for their lysine-specific demethylase 1 inhibitory activity and cell growth inhibitory activity. In enzyme assays, the (1S,2R)-isomer was approximately four times more potent than the (1R,2S)-isomer. In cell growth inhibition assays, the two isomers showed similar activity in HEK293 cells and SH-SY5Y cells, whereas the (1S,2R)-isomer showed approximately four times more potent activity than the (1R,2S)-isomer in HeLa cells.     

Fatty acid and lipid class composition in eyes and brain from teleosts and elasmobranchs

The effect of 17beta-estradiol (E(2)) on osmoregulatory performance was examined in the euryhaline killifish, Fundulus heteroclitus. Fish were injected once with 1, 2 and 5 microg g(-1) E(2) and, 6 h after injection, transferred from 1 ppt seawater (SW) to full strength SW (40 ppt) or from SW to 1 ppt SW. In another set of experiments, fish were injected four times on alternate days with 2 microg g(-1) E(2) and then, 6 h after the last injection, transferred from 1 ppt SW to SW or from SW to 1 ppt SW. Fish were sampled 18 h after transfer (i.e., 24 h post-injection), and plasma osmolality, Na(+) and Cl(-) concentration and gill K(+)-pNPPase activity (a reflection of the sodium pump) were examined. Transfer from 1 ppt SW to SW resulted in significantly increased plasma osmolality, but did not affect gill K(+)-pNPPase activity. A single dose of E(2) (1, 2 and 5 microg g(-1)) prior to transfer from 1 ppt SW to SW increased plasma osmolality and decreased gill K(+)-pNPPase activity in a dose-dependent manner. Prolonged treatment with E(2) increased plasma osmolality and decreased gill K(+)-pNPPase activity in 1 ppt SW-adapted fish. Transfer of fish thus treated from 1 ppt SW to SW increased plasma osmolality and did not alter gill K(+)-pNPPase activity. Transfer from SW to 1 ppt SW had no significant effect on plasma osmolality or gill K(+)-pNPPase activity. Only the highest single dose of E(2) (5 microg g(-1)) prior to transfer from SW to 1 ppt SW decreased gill K(+)-pNPPase activity. Prolonged treatment with 2 microg g(-1) E(2) decreased gill K(+)-pNPPase activity only following transfer from SW to 1 ppt SW. The results substantiate an inhibitory action of E(2) on hypoosmoregulatory capacity in this euryhaline teleost.     

Similarities and differences between the characteristics of gibberellin-binding protein and gibberellin 2-oxidases in adzuki bean (Vigna angularis) seedlings

Gibberellin-binding proteins (GBPs) were purified ca. 230,000 fold. The characteristics of adzuki GBP were examined and compared with those of a recombinant gibberellin 2-oxidase (rVaGA2oxA1) that was fused with glutathione S-transferase (GST). VaGA2oxA1 was most abundantly expressed in etiolated adzuki bean seedlings, and VaGA2oxA1 and GBPs from adzuki bean seedlings showed gibberellin-binding activity when incubated with 2-oxoglutarate and Co2+. Both rVaGA2oxA1 and partially purified GBPs from adzuki bean seedlings showed very similar selectivity to gibberellins in binding assays, where biologically active gibberellins such as GA4, GA3, GA7, and GA1 showed higher binding affinity than biologically inactive gibberellins such as GA8, GA34, and 3-epi-GA4. The polyclonal antibody raised against rVaGA2oxA1 cross-reacted with all rVaGA2oxs (rVaGA2oxA1, rVaGA2oxA2, rVaGA2oxB1, rVaGA2oxB2, and rVaGA2oxB3) whose cDNAs were cloned from adzuki bean seedlings. Treated with the antibody, the recombinants that originally showed gibberellin-binding activity lost both binding activity and enzymatic activity. In contrast to the recombinants, the gibberellin-binding activity of GBPs from adzuki bean seedlings was hardly affected by the antibody treatment. The GBPs showed very weak gibberellin 2-oxidase-like activity, and it was not affected by the antibody treatment either. These observations suggest that a major component that showed GA-binding activity was apparently different from any gibberellin 2-oxidase cloned from the seedlings.     

Coagulant properties of hybrid human/porcine factor VIII molecules.

Human and porcine factor VIII (fVIII) are activated by thrombin to form a heterotrimer composed of subunits designated A1 and A2 derived from the fVIII heavy chain (HC) and a subunit designated A3-C1-C2 derived from the fVIII light chain (LC). Human and porcine fVIII were activated at the same rate to the same peak levels but dissociation of the A2 subunit and concomitant loss of fVIIIa activity at pH 7.4 and 22 degrees C was 3-fold faster with human fVIIIa compared to porcine fVIIIa (0.35 min-1 versus 0.12 min-1, respectively). To determine structural requirements for the increased activity of porcine fVIII, plasma-derived hybrid human/porcine fVIII molecules were isolated. Porcine HC/human LC (pHC/hLC) fVIII had 44-fold higher coagulant activity than reconstituted human fVIII (hHC/hLC), 40-fold higher activity than hHC/pLC, and slightly (1.4-fold) higher activity than reconstituted porcine fVIII (pHC/pLC). Additionally, human and porcine A2 subunits and inactive A1/A3-C1-C2 human and porcine dimers were isolated and reconstitution experiments were done. Addition of the porcine A2 subunit to the human A1/A3-C1-C2 dimer produced coagulant activity similar to that found with porcine fVIIIa and superior to human fVIIIa. These results suggest that human fVIII has weaker coagulant activity than porcine fVIII due to faster dissociation of the A2 subunit and that the A2 subunit itself is responsible for the difference.     

Effect of saponin immersion on enhancement of the immune response of white shrimp Litopenaeus vannamei and its resistance against Vibrio alginolyticus

The haemocyte count, phenoloxidase (PO) activity, specific alpha(2)-macroglobulin (alpha2-M) activity, respiratory burst, superoxide dismutase (SOD) activity, glutathione peroxidase (GPx) activity, phagocytic activity, and clearance efficiency against Vibrio alginolyticus were examined when the white shrimp Litopenaeus vannamei (10.42+/-2.0g) were immersed in seawater (34 per thousand) containing different concentrations of saponin (0, 0.5, 1 and 2mgL(-1)) for 24, 48 and 72h. Hyaline cells (HC), the total haemocyte count (THC), specific alpha2-M activity, respiratory burst, SOD activity, and GPx activity directly increased with the saponin concentration, whereas PO activity was inversely related to the saponin concentration. White shrimp L. vannamei that were immersed in saponin at 1 and 2mgL(-1) showed increased phagocytic activity and clearance efficiency to V. alginolyticus over 48-72h. In another experiment, shrimp immersed in seawater containing different concentrations of saponin after 72h were challenged with V. alginolyticus at 3.2x10(5) colony-forming units (cfu)shrimp(-1), and then placed in seawater. The survival rate of shrimp immersed in seawater containing saponin at either dose was significantly higher than that of control shrimp after 12h, as well as at the termination of the experiment (5days after the challenge). It was therefore concluded that L. vannamei immersed in water containing saponin at 2mgL(-1) or less exhibited an immunomodulatory effect, as well as protection against V. alginolyticus infection.     

Identification of human cytochrome P450 isoforms involved in the 7-hydroxylation of chlorpromazine by human liver microsomes

Studies to identify the cytochrome P450 (CYP) isoform(s) involved in chlorpromazine 7-hydroxylation were performed using human liver microsomes and cDNA-expressed human CYPs. The kinetics of chlorpromazine 7-hydroxylation in human liver microsomes showed a simple Michaelis-Menten behavior. The apparent Km and Vmax values were 3.4+/-1.0 microM and 200.5+/-83.7 pmol/min/mg, respectively. The chlorpromazine 7-hydroxylase activity in human liver microsomes showed good correlations with desipramine 2-hydroxylase activity (r = 0.763, p < 0.05), a marker activity for CYP2D6, and phenacetin O-deethylase activity (r = 0.638, p < 0.05), a marker activity for CYP1A2. Quinidine (an inhibitor of CYP2D6) completely inhibited while alpha-naphthoflavone (an inhibitor of CYP1A2) marginally inhibited the chlorpromazine 7-hydroxylase activity in a human liver microsomal sample showing high CYP2D6 activity. On the other hand, alpha-naphthoflavone inhibited the chlorpromazine 7-hydroxylase activity to 55-65% of control in a human liver microsomal sample showing low CYP2D6 activity. Among eleven cDNA-expressed CYPs studied, CYP2D6 and CYP1A2 exhibited significant activity for the chlorpromazine 7-hydroxylation. The Km values for the chlorpromazine 7-hydroxylation of both cDNA-expressed CYP2D6 and CYP1A2 were in agreement with the Km values of human liver microsomes. These results suggest that chlorpromazine 7-hydroxylation is catalyzed mainly by CYP2D6 and partially by CYP1A2.     

Annexin I and dexamethasone effects on phospholipase and cyclooxygenase activity in human synoviocytes

Annexin I is a glucocorticoid-induced mediator with anti-inflammatory activity in animal models of arthritis. We studied the effects of a bioactive annexin I peptide, ac 2-26, dexamethasone (DEX), and interleukin-1beta (IL-1beta) on phospholipase A2 (PLA2) and cyclooxygenase (COX) activities and prostaglandin E2 (PGE2) release in cultured human fibroblast-like synoviocytes (FLS). Annexin I binding sites on human osteoarthritic (OA) FLS were detected by ligand binding flow cytometry. PLA2 activity was measured using 3H-arachidonic acid release, PGE2 release and COX activity by ELISA, and COX2 content by flow cytometry. Annexin I binding sites were present on human OA FLS. Annexin I peptide ac 2-26 exerted a significant concentration-dependent inhibition of FLS constitutive PLA2 activity, which was reversed by IL-1beta. In contrast, DEX inhibited IL-1beta-induced PLA2 activity but not constitutive activity. DEX but not annexin I peptide inhibited IL-1beta-induced PGE2 release. COX activity and COX2 expression were significantly increased by IL-1beta. Annexin I peptide demonstrated no inhibition of constitutive or IL-1beta-induced COX activity. DEX exerted a concentration-dependent inhibition of IL-1beta-induced but not constitutive COX activity. Uncoupling of inhibition of PLA2 and COX by annexin I and DEX support the hypothesis that COX is rate-limiting for PGE2 synthesis in FLS. The effect of annexin I but not DEX on constitutive PLA2 activity suggests a glucocorticoid-independent role for annexin I in autoregulation of arachidonic acid production. The lack of effect of annexin I on cytokine-induced PGE2 production suggests PGE2-independent mechanisms for the anti-inflammatory effects of annexin I in vivo.     

Catalase T and Cu,Zn-superoxide dismutase in the acetic acid-induced programmed cell death in Saccharomyces cerevisiae

To investigate the role of catalase and superoxide dismutase (SOD) in the acetic acid (AA) induced yeast programmed cell death (AA-PCD), we compared Saccharomyces cerevisiae cells (C-Y) and cells individually over-expressing catalase T (CTT1-Y) and Cu,Zn-SOD (SOD1-Y) with respect to cell survival, hydrogen peroxide (H2O2) levels and enzyme activity as measured up to 200 min after AA treatment. AA-PCD does not occur in CTT1-Y, where H2O2 levels were lower than in C-Y and the over-expressed catalase activity decreased with time. In SOD1-Y, AA-PCD was exacerbated; high H2O2 levels were found, SOD activity increased early, remaining constant en route to AA-PCD, but catalase activity was strongly reduced.     

Induction of gene expression by IL-1 in NIH 3T3 cells. Possible requirement of protein kinase C activity and independence from arachidonic acid metabolism

NIH 3T3 fibroblasts were transfected with the chloramphenicol-acetyltransferase (CAT) gene under the control of the SV40 early promoter, which can be stimulated by IL-1. CAT activity in cell lysates and PGE2 release in the supernatants were measured in control and stimulated cell cultures in parallel. Human IL-1 beta (180 pM) and human rTNF-alpha (3 nM) significantly stimulated both CAT activity and PGE2 release. The combined incubation of the two cytokines resulted in a synergistic effect on PGE2 release. The addition of AA (30 microM) greatly stimulated PGE2 release without affecting CAT activity. Similarly, drugs interfering with AA metabolism were without effect on CAT activity although profoundly reducing PGE2 release. Forskolin (0.1 microM) did not modify either parameter. The glucocorticoid fluocinolone (20 nM) was able to decrease both parameters. Protein kinase inhibitors H7 (5-50 microM) and sphingosine (50 microM) inhibited only IL-1-induced CAT activity, whereas H8 (5-50 microM) and HA1004 (50 microM) were ineffective on both parameters. PMA (0.5 microM) and R59 022, a diacylglycerol kinase inhibitor (10 microM), did not modify either control or IL-1-induced CAT activity. IL-1-stimulated PGE2 release was potentiated by PMA, although this effect was not inhibited by H7. The data suggest that: 1) in NIH 3T3 cells the activation of AA metabolism by IL-1 is not involved in IL-1-induced gene expression; 2) protein kinase C activity is required but not sufficient for IL-1-induced gene expression; and 3) PMA may stimulate AA metabolism by a mechanism in part independent of protein kinase activity.     

Anti-inflammatory phloroglucinol derivatives from Hypericum empetrifolium

Phytochemical investigation of Hypericum empetrifolium Willd. (Clusiaceae), a species native to Greece and Turkey has led to the bioassay-guided identification of two acylphloroglucinol derivatives with potent in vitro anti-inflammatory activity. Using NMR spectroscopy and mass spectrometry, the acylphloroglucinol derivatives were characterized as 3-geranyl-1-(2'-methylpropanoyl)phloroglucinol (1) and 3-geranyl-1-(2'-methylbutanoyl)phloroglucinol (2). Hypotheses are proposed regarding the biosynthetic origin of these and similar acylphloroglucinols from related Hypericum species. Compounds 1 and 2 were evaluated for in vitro inhibitory activity against COX-1, COX-2 and 5-LOX catalyzed LTB(4) formation. Compound 1 displayed good activity (IC(50) values: 6.0, 29.9, and 2.2 μM, respectively) in all three assays. Compound 2 showed good activity (IC(50) value: 5.8 μM) against LTB(4) formation and moderate activity (IC(50) value: 26.2 μM) against COX-1.     

Purification and properties of glutamine synthetase from the non-N2-fixing cyanobacterium Phormidium laminosum.

Soluble glutamine synthetase activity (L-glutamate:ammonia ligase, ADP forming, EC 6.3.1.2) was purified to electrophoretic homogeneity from the filamentous non-N2-fixing cyanobacterium Phormidium laminosum (OH-1-p.Cl1) by using conventional purification procedures in the absence of stabilizing ligands. The pure enzyme showed a specific activity of 152 mumol of gamma-glutamylhydroxamate formed.min-1 (transferase activity), which corresponded to 4.4 mumol of Pi released.min-1 (biosynthetic activity). The relative molecular mass of the native enzyme was 602 kilodaltons and was composed of 12 identically sized subunits of 52 kilodaltons. Biosynthetic activity required the presence of Mg2+ as an essential activator, although Co2+ and Zn2+ were partially effective. The kinetics of activation by Mg2+, Co2+, and Zn2+ were sigmoidal, and concentrations required for half-maximal activity were 18 mM (h = 2.2), 6.3 mM (h = 5.6), and 6.3 mM (h = 2.45), respectively. However, transferase activity required Mn2+ (Ka = 3.5 microM), Cu2+, Co2+, or Mg2+ being less effective. The substrate affinities calculated for L-Glu, ammonium, ATP, L-Gln, and hydroxylamine were 15, 0.4, 1.9 (h = 0.75), 14, and 4.1 mM, respectively. Optimal pH and temperature were 7.2 and 55 degrees C for biosynthetic activity and 7.5 and 45 degrees C for transferase activity. The biosynthetic reaction mechanism proceeded according to an ordered three-reactant system, the binding order being ammonium, L-Glu, and ATP. The presence of Mn2+ or Mg2+ drastically affected the thermostability of transferase and biosynthetic activities. Heat inactivation of biosynthetic activity in the presence of Mn2+ obeyed first-order kinetics, with an Ea of 76.8 kcal (ca. 321 kJ) mol-1. Gly, L-Asp, L-Ala, L-Ser and, with lower efficiency, L-Lys and L-Met, L-Lys, and L-Glu inhibited only transferase activity. No cumulative inhibition was observed when mixtures of amino acids were used. Biosynthetic activity was inhibited by AMP (Ki= 7 mM), ADP (Ki= 2.3 mM), p-hydroxymercuribenzoate (Ki= 25 microM), and L-methionine-D, L-sulfoximine (Ki= 2 microM). The enzyme was not activated in vitro by chemically reduced Anabaena thioredoxin. This is the first report of glutamine synthetase activity purified from a filamentous non-N2-fixing cyanobacterium.     

Induction of IL-2 receptor expression and proliferation of T cell clones by a novel cytokine(s).

We found a unique T cell IL-2 receptor (IL-2R)3-inducing activity in the supernatant (SN) of the TH1 clone stimulated with antigen on spleen cells as antigen-presenting cells (APC). We have tentatively named this activity the IL-2R-inducing factor (IL-2RIF) and have characterized the activity. The SN induced IL-2R and proliferation of TH1 clones stimulated with B cell APC, which could not induce IL-2R in the absence of the SN. Other known cytokines were examined for a IL-2RIF activity; however, none of cytokines examined exerted a similar activity. Moreover, the neutralizing antibodies against the known cytokines tested did not block the IL-2RIF activity in the SN. When TH1 clones were stimulated with immobilized anti-CD3 or with fixed B cell APC in the presence of partially purified IL-2RIF, these clones expressed IL-2R and showed IL-2-dependent proliferation, whereas they induced neither IL-2R expression nor proliferation in the absence of IL-2RIF activity. These observations suggest that IL-2RIF activity is mediated by a novel cytokine(s) and the cytokine plays an important role as a second signal in the activation of the TH1 clone.     

Microbial and xanthine dehydrogenase inhibitory activity of some flavones

Xanthine dehydrogenase (XDH) is responsible for the pathological condition called Gout. In the present study different flavones synthesized from chalcone were evaluated in vitro for their inhibitory activity. Inhibitory activity of flavones on XDH was determined in terms of inhibition of uric acid synthesis from Xanthine. The enzymatic activity was found maximum at pH 7.5 and temperature 40 degrees C. The flavones 6-chloro-2-[3-(4-hydroxy-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(1)) and 6-chloro-7methyl-2-[3-(4-chloro-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one(F(2)),were noncompetitive and competitive inhibitor with Ki values 1.1 and 0.22 respectively. The flavones (F(1)), (F(2)), 6-chloro-2-[3-(4-chloro-phenyl)-1phenyl-1-H-pyrazol-4-yl]-chromen-4-one(F(3)), 8-bromo-6-chloro-2-[3-(4-chloro-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(4)), 2-[3-(4-hydroxy-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(5)) and 6-methyl-2-[3-(4-hydroxy-phenyl)-1-phenyl-1-H-pyrazol-4-yl]-chromen-4-one (F(6)) were also screened for their antimicrobial activity, measured in terms of zone of inhibition. A broad spectrum antifungal activity was obtained against Trichoderma viridae, Candida albicans, Microsporum cannis, Penicillium chrysogenum and Fusarium moniliformae. In case of Aspergillus niger and Aspergillus flavous only spore formation was affected, while antibacterial activity was observed against Staphylococcus aureus, Bacillus subtilis and Serratia marsecens only. The flavones were further analyzed for quantitative structural activity relationship study (QSAR) by using PASS, online software to determine their Pa value. Toxicity and drug relevant properties were revealed by PALLAS software in terms of their molecular weight. Log P values were also studied. The result showed both the F(1) and F(2) flavones as antigout and therefore supports the development of novel drugs for the treatment of gout.     

Synthesis and biological evaluation of novel indenopyrazole derivatives

A series of novel indenopyrazole derivatives 2a‐j and 3a‐j were synthesized from the reaction of 1‐(4‐(hydroxy(1‐oxo‐1,3‐dihydro‐2 H‐inden‐2‐ylidene)methyl)phenyl)‐3‐phenylurea derivatives 1a‐j with hydrazine and phenylhydrazine, respectively. The obtained novel indenopyrazoles ( 2a‐j and 3a‐j ) were evaluated for anticancer activity against HeLa and C6 cell lines. Antiproliferative activity was determined by the BrdU proliferation ELISA assay; 2a , 2b , 2d , 2h , and 3h were found to be the most active compounds. The compounds were also screened for antimicrobial activity, and all compounds showed moderate activity against used microorganisms.     

High glucose enhances MMP-2 production in adventitial fibroblasts via Akt1-dependent NF-kappaB pathway

To understand the role of adventitial fibroblasts (AF) in diabetic vascular diseases, the importance of high glucose (HG, 25mM) on matrix metalloproteinase-2 (MMP-2) production in AF was determined. HG enhanced mRNA, protein and gelatinolytic activity of MMP-2. The enhanced MMP-2 activity was significantly attenuated not only by a PI3K inhibitor but also by an Akt inhibitor. These HG-induced MMP-2 responses were markedly reduced in Akt1-deficient (1KO) cells. The diminished HG-induced MMP-2 responses were completely restored by re-expression of Akt1. Both the reporter activity and electrophoretic mobility shift assay for activator protein-1 and nuclear factor-kappa B (NF-kappaB) were enhanced by HG, but NF-kappaB were not increased in 1KO cells. Furthermore, HG-induced MMP-2 responses were markedly suppressed by NF-kappaB decoy oligodeoxynucleotides. Based on these results, it is suggested that HG augments MMP-2 production via PI3K/Akt1/NF-kappaB pathway.     

Cortical layer 1 and layer 2/3 astrocytes exhibit distinct calcium dynamics in vivo

Cumulative evidence supports bidirectional interactions between astrocytes and neurons, suggesting glial involvement of neuronal information processing in the brain. Cytosolic calcium (Ca(2+)) concentration is important for astrocytes as Ca(2+) surges co-occur with gliotransmission and neurotransmitter reception. Cerebral cortex is organized in layers which are characterized by distinct cytoarchitecture. We asked if astrocyte-dominant layer 1 (L1) of the somatosensory cortex was different from layer 2/3 (L2/3) in spontaneous astrocytic Ca(2+) activity and if it was influenced by background neural activity. Using a two-photon laser scanning microscope, we compared spontaneous Ca(2+) activity of astrocytic somata and processes in L1 and L2/3 of anesthetized mature rat somatosensory cortex. We also assessed the contribution of background neural activity to the spontaneous astrocytic Ca(2+) dynamics by investigating two distinct EEG states ("synchronized" vs. "de-synchronized" states). We found that astrocytes in L1 had nearly twice higher Ca(2+) activity than L2/3. Furthermore, Ca(2+) fluctuations of processes within an astrocyte were independent in L1 while those in L2/3 were synchronous. Pharmacological blockades of metabotropic receptors for glutamate, ATP, and acetylcholine, as well as suppression of action potentials did not have a significant effect on the spontaneous somatic Ca(2+) activity. These results suggest that spontaneous astrocytic Ca(2+) surges occurred in large part intrinsically, rather than neural activity-driven. Our findings propose a new functional segregation of layer 1 and 2/3 that is defined by autonomous astrocytic activity.     

Drug Resistance of Staphylococci

Induction of chloramphenicol (CM) resistance in Staphylococcus aureus was investigated by using several CM derivatives. It was found that dl-threo-1-p-nitrophenyl-2-dichloroacetamino-1,3-dichloropropane has high antibacterial activity but low activity of induction for CM resistance. In spite of low antibacterial activity, induction of CM resistance occurred after prior treatment with dl-threo-1-p-nitrophenyl-2-dichloroacetamino-3-chloropropane-1-ol. It was found that dl-chloramphenicol di-acetate, dl-threo-1-p-nitrophenyl-2-dichloroacetamino-3-bromopropane-1-ol and dl-threo-1-phenyl-2-dichloroacetamino-1,3-propanediol have induction ability in spite of the absence of antibacterial activity. Other derivatives were classified into two groups; (1) low antibacterial activity and induction of CM resistance and (2) loss of both activities.