Complementation of the amylose-free starch mutant of potato (Solanum tuberosum.) by the gene encoding granule-bound starch synthase

Summary Agrobacterium rhizogenes-mediated introduction of the wild-type allele of the gene encoding granulebound starch synthase (GBSS) into the amylose-free starch mutantamf of potato leads to restoration of GBSS activity and amylose synthesis, which demonstrates thatAmf is the structural gene for GBSS. Amylose was found in columella cells of root tips, in stomatal guard cells, tubers, and pollen, while in the control experiments using only vector DNA, these tissues remained amylose free. This confirms the fact that, in potato, GBSS is the only enzyme responsible for the presence of amylose, accumulating in all starch-containing tissues. Amylose-containing transformants showed no positive correlation between GBSS activity and amylose content, which confirms that the former is not the sole regulating factor in amylose metabolism.     

Selection of Arabidopsis mutants overexpressing genes driven by the promoter of an auxin-inducible glutathione S-transferase gene

Transgenic arabidopsis plants were isolated that contained a T-DNA construct in which the promoter of an auxin-inducible glutathione S-transferase (GST) gene from tobacco was fused to the kanamycin resistance (nptII) as well as to the -glucuronidase (gusA) reporter gene. Subsequently, seeds were treated with EMS to obtain mutants in which both reporter gene fusions were up-regulated. Northern analysis showed that the mRNA level of a related, endogenous auxin-inducible GST gene of Arabidopsis was increased in some of these mutants as well. Two of the gup (GST up-regulated) mutants were characterized in more detail and roughly mapped. Both had epinastic cotyledons and leaves, a phenotype that turned out to be linked to the gup mutation.     

Purification and properties of the phenprocoumon-induced decarboxyfactor X from bovine plasma. A comparison to normal factor X.

1. By a procedure involving adsorption to barium sulfate, chromatography on DEAE-Sephadex and QAE-Sephadex and preparative polyacrylamide gel electrophoresis, decarboxyfactor X was purified from plasma of phenprocoumon-treated cows. No contaminants could be detected in the final preparation by polyacrylamide gel electrophoresis and zone-electrophoresis. 2. The molecular weight of decarboxyfactor X, as determined by sodium dodecyl sulfate polyacrylamide gel electrophoresis is approximately 55 000, which is equal to that of factor X. The protein consists of two polypeptide chains with molecular weights of 44 000 and 17 000. 3. Decarboxyfactor X has antigenic determinants in common with normal factor X. 4. The amino acid composition and aminoterminal amino acids of normal factor X and decarboxyfactor X are identical. 5. Less than one residue of gamma-carboxyglutamate could be detected per mole of decarboxyfactor X. 6. In the absence of Ca2+, normal factor X has a slightly higher electrophoretic mobility than decarboxyfactor X. In the presence of Ca2+ the mobility of factor X decreases considerably while the mobility of decarboxyfactor X remains unaltered.     

Atmospheric electric discharge into water

Results are presented from experimental studies of spark discharges excited between a needle electrode placed over the water surface and a plane electrode immersed in water. The electron density in the spark channels gliding over the water surface and the velocity of their radial propagation are determined. It is found that, when the discharge channel reaches the water, the conductivity of the water surface becomes anomalously high, which looks like a peculiar kind of transformation of a needle electrode over the water surface into a plane electrode adjacent to this surface.     

Co-expression of human ABCG5 and ABCG8 in insect cells generates an androstan stimulated membrane ATPase activity

Mutations in the ATP-binding cassette (ABC) proteins ABCG5 or ABCG8 cause sitosterolemia, a condition with increased accumulation of plant sterols. Upon high level expression of the ABCG5 and ABCG8 proteins in baculovirus-Sf9 cell expression system we found a distinct, vanadate sensitive ATPase activity in isolated membrane preparations only when the two proteins were co-expressed. This ATPase activity was significantly stimulated by the addition of certain androgen hormones and analogs, and was effectively inhibited by progesterone. Our results provide a new aspect of biochemical and functional characterization of the ABCG5/ABCG8 proteins and their possible involvement in steroid hormone transport or regulation.     

Biological recovery of the Bohemian Forest lakes from acidification

A limnological survey of eight small, atmospherically acidified, forested glacial lakes in the Bohemian Forest (?umava, Böhmerwald) was performed in September 2003. Water chemistry of the tributaries and surface layer of each lake was determined, as well as species composition and biomass of the plankton along the water column, and littoral macrozoobenthos to assess the present status of the lakes. The progress in chemical reversal and biological recovery from acid stress was evaluated by comparing the current status of the lakes with results of a survey four years ago (1999) and former acidification data since the early 1990s. Both the current chemical lake status and the pelagic food web structure reflected the acidity of the tributaries and their aluminium (Al) and phosphorus (P) concentrations. One mesotrophic (Ple?né jezero) and three oligotrophic lakes (?erné jezero, ?ertovo jezero, and Rachelsee) are still chronically acidified, while four other oligotrophic lakes (Kleiner Arbersee, Prá?ilské jezero, Grosser Arbersee, and Laka) have recovered their carbonate buffering system. Total plankton biomass was very low and largely dominated by filamentous bacteria in the acidified oligotrophic lakes, while the mesotrophic lake had a higher biomass and was dominated by phytoplankton, which apparently profited from the higher P input. In contrast, both phytoplankton and crustacean zooplankton accounted for the majority of plankton biomass in the recovering lakes. This study has shown further progress in the reversal of lake water chemistry as well as further evidence of biological recovery compared to the 1999 survey. While no changes occurred in species composition of phytoplankton, a new ciliate species was found in one lake. In several lakes, this survey documented a return of zooplankton (e.g., Cladocera: Ceriodaphnia quadrangula and Rotifera: three Keratella species) and macrozoobenthos species (e.g., Ephemeroptera and Plecoptera). The beginning of biological recovery has been delayed for ～20 years after chemical reversal of the lakes.     

Primary structure of apolipophorin-III from the greater wax moth,Galleria mellonella

The complete amino acid sequence of apolipophorin-III (apoLp-III), a lipid-binding hemolymph protein from the greater wax moth,Galleria mellonella, was determined by protein sequencing. The mature protein consists of 163 amino acid residues forming a protein of 18,075.5 Da. Its sequence is similar to apoLp-III from other Lepidopteran species, but remarkably different from the apoLp-IIIs of insects from other orders. As shown by mass spectrometric analysis, the protein carries no modifications. Thus, all of its known physiological functions, including its recently discovered immune response-stimulating activity, must reside in the protein itself.     

Estimation of tree biomass of Norway spruce forest in the Plešné Lake catchment,the Bohemian Forest

This paper evaluates the total biomass and pools of major nutrients and ecologically important metals of the tree layer in the catchment of Ple?né jezero (PL) in the Bohemian Forest (?umava, Czech Republic), and compares them to analogous data on understory vegetation and soils. The results are based on field measurements and semi-automatic image analyses of aerial orthophotographs. The tree layer was relatively sparse with open canopy in some parts of the catchment. Stand density varied between 44 and 328 individuals per hectare. The catchment weighted mean total biomass of trees was 134 t ha^?1 dry weight, of which needles, branches, roots, and stems represented 5%, 10%, 14%, and 71%, respectively. The stem wood and bark represented 67% and 4%, respectively, of the total tree biomass. The catchment weighted mean element pools were 568 and 3.0 mol m^?2 (i.e., 68 and 0.42 t ha^?1) for C and N, respectively. The other pools were 76 mmol P m^?2, 602 mmol Ca m^?2, 133 mmol Mg m^?2, 39 mmol Na m^?2, 347 mmol K m^?2, 19 mmol Al m^?2, 6.2 mmol Fe m^?2, and 35 mmol Mn m^?2. The element pools accumulated in the tree biomass represented from < 1% (Al, Fe) to 37% (C) of their total pools (soil + tree layer + understory vegetation) in the catchment. Pools of Ca and Mg in the tree biomass were similar to their exchangeable pools in the catchment soils, while those of K were 3 times higher. Nutrient (N, P, Ca, Mg, and K) and C pools in the tree biomass were 2–11 times higher than those in the understory vegetation, with the minimum for P and maximum for C.     

CELL‐SPECIFIC EXTRACELLULAR PHOSPHATASE ACTIVITY OF DINOFLAGELLATE POPULATIONS IN ACIDIFIED MOUNTAIN LAKES1

High bulk extracellular phosphatase activity (PA) suggested severe phosphorus (P) deficiency in plankton of three acidified mountain lakes in the Bohemian Forest. Bioavailability of P substantially differed among the lakes due to differences in their P loading, as well as in concentrations of aluminum (Al) and its species, and was accompanied by species‐specific responses of phytoplankton. We combined the fluorescently labeled enzyme activity (FLEA) assay with image cytometry to measure cell‐specific PA in natural populations of three dinophyte species, occurring in all the lakes throughout May–September 2007. The mean cell‐specific PA varied among the lakes within one order of magnitude: 188–1,831 fmol · cell^?1 · h^?1 for Gymnodinium uberrimum (G. F. Allman) Kof. et Swezy, 21–150 fmol · cell^?1 · h^?1 for Gymnodinium sp., and 22–365 fmol · cell^?1 · h^?1 for Peridinium umbonatum F. Stein. To better compare cell‐specific PA among the species of different size, the values were normalized per unit of cell biovolume (amol · μm^?3 · h^?1) for further statistical analysis. A step‐forward selection identified concentrations of total and ionic Al together with pH as significant factors (P < 0.05, Monte Carlo permutation test), explaining cumulatively 57% of the total variability in cell‐specific PA. However, this cell‐specific PA showed an unexpected reverse trend compared to an overall gradient in P deficiency of the lake plankton. The autecological insight into dinophyte cell‐specific PA therefore suggested other factors, such as light availability, mixotrophy, and/or zooplankton grazing, causing further PA variations among the acidified lakes.     

The adsorption of prothrombin to phosphatidylserine multilayers quantitated by ellipsometry

We investigated by means of an automated ellipsometer the adsorption of prothrombin from a buffer solution by multilayers of 14:0/14:0- and 18:1/18:1-phosphatidylserine (PS) stacked on chromium slides. In this instrument thickness and refractive index of the adsorbed phospholipid and proteins are monitored continuously. Two equations are derived to relate the mass of stacked phospholipids and the mass of protein adsorbed to the thickness and refractive index. These equations are based upon the Lorentz-Lorenz relation among the molar refractivities, refractive indices, and the densities of binary mixtures. Experimental validation of these equations is performed by measuring stacked multilayers of known mass of phosphatidylserine and the adsorption of [125I] albumin and [3H]prothrombin on these multilayers. Using these equations we measured the dissociation constants Kd and the number of binding sites nb of prothrombin. Values of Kd = 0.15 x 10(-8) M and nb = 122 molecules of PS/molecule of prothrombin were observed for di C14:0 PS and values of Kd = 0.45 x 10(-8) M and nb = 54 molecules of PS/molecule of prothrombin for di C18:1 PS. These data compare well to data obtained by other methods available in the literature.