Bacterial periphyton of the Vltava River

Bacterial periphyton formed during 48 hours was studied by glass slide method and direct counting in Vltava River in Praha, Czechoslovakia. At water temperatures 8–11°C the numbers of rods ranged between 24,000 and 336,000 per 1 cm² and those of cocci between 30,000 and 228,000. The relation rods: cocci ranged between 0,9 and 2,4 with an average value of 1,7, whereas in a fishpond this average was 0,5. Among the periphyton 81,3% bacterial cells were active. The rods: cocci relation seems to be a good indicator of water pollution by organic matter, but numbers distinguishing the individual saprobic levels cannot be given yet.

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Zusammenfassung Es wurde der bakterielle Bewuchs von Glassplatten im Vltava-Fluss in Praha untersucht. Zweitägige Exposition erwies sich als am meisten geeignet, um den Bewuchs mikroskopisch durch direkte Zählung quantitativ zu erfassen. In Abhängigkeit von der Tiefe, Wassertemperatur, Verunreinigungsgrad, Sonnenstrahlung u.a. entwickelte sich der Bewuchs quantitativ unterschiedlich und zeigte auch eine unterschiedliche Relation von Stäbchen zu Kokken. Im beta-mesosaproben Bereich wurden im Herbst (Wassertemperaturen 8–11 °C) 24.000 bis 336.000 Stäbchen und 30.000 bis 228.000 Kokken per 1 cm² gefunden, mit den Mittelwerten 163.100 Stäbchen und 104.100 Kokken. Die Vergleichswerte von einem Fischteich in Motol lagen für Stäbchen im gleichen Bereich, während die Kokken, bis 254.000 erreichten.Die Relation Stäbchen: Kokken variierte im Vltava-Fluss zwischen 0,9 (nur einmal) und 2,4 mit dem Mittelwert 1,7, im Fischteich zwischen 0,4 ufnd 0,7 mit dem Mittelwert 0,5. Es hat sich erwiesen, dass diese Relation brauchbare Angaben über die organische Verunreinigung gibt. Leider liegen bisher zu wenige Ergebnisse vor, um eine Skale gegenüber den Saprobitätsstufen zu errichten.Unter den Bewuchsbakterien gab es in der Vltava durchschnittlich 81,3% aktive Zellen, wie durch Fluoreszenzanalyse festgestellt wurde.Fast alle Daten indizieren eine schwächere Verunreinigung des Wassers am linken Ufer als am rechten.

     

Inhibition of Monoacylglycerol Lipase Activity Decreases Glucose-Stimulated Insulin Secretion in INS-1 (832/13) Cells and Rat Islets

Lipid signals derived from lipolysis and membrane phospholipids play an important role in glucose-stimulated insulin secretion (GSIS), though the exact secondary signals remain unclear. Previous reports have documented a stimulatory role of exogenously added mono-acyl-glycerol (MAG) on insulin secretion from cultured β-cells and islets. In this report we have determined effects of increasing intracellular MAG in the β-cell by inhibiting mono-acyl-glycerol lipase (MGL) activity, which catalyzes the final step in triacylglycerol breakdown, namely the hydrolysis of MAG to glycerol and free fatty acid (FA). To determine the role of MGL in GSIS, we used three different pharmacological agents (JZL184, MJN110 and URB602). All three inhibited GSIS and depolarization-induced insulin secretion in INS-1 (832/13). JZL184 significantly inhibited both GSIS and depolarization-induced insulin secretion in rat islets. JZL184 significantly decreased lipolysis and increased both mono- and diacyglycerol species in INS-1 cells. Analysis of the kinetics of GSIS showed that inhibition was greater during the sustained phase of secretion. A similar pattern was observed in the response of Ca²⁺ to glucose and depolarization but to a lesser degree suggesting that altered Ca²⁺ handling alone could not explain the reduction in insulin secretion. In addition, a significant reduction in long chain-CoA (LC-CoA) was observed in INS-1 cells at both basal and stimulatory glucose following inhibition of MGL. Our data implicate an important role for MGL in insulin secretion.     

Flora von Oesterreich-Ungarn

Ohne ZusammenfassungDas Referat bezieht sich auf den Zeitraum vom 1. Jänner bis 1. Juni 1890.     

A Comparison of Protein and mRNA Expression during Development of the Soil Dwelling Prokaryote (S. coelicolor)

In this paper, correlation analysis of protein and mRNA levels in the soil dwelling bacteria Streptomyces coelicolor (S. coelicolor M145) is presented during development of the population as it grew in liquid medium using three biological and two technical replicates, measured during exponential growth, and its entry into the stationary phase. The proteome synthesis time series are compared with the gene expression time series measured previously under identical experimental conditions. Results reveal that about one third of protein/mRNA synthesis profiles are well correlated while another third are correlated negatively. Functional analysis of the highly correlated groups is presented. Based on numerical simulation, the negative correlation between protein and mRNA is shown to be caused by the difference between the rate of translation and protein degradation.