Comparison of gas chromatography-mass spectrometry,radioimmunoassay and bioassay for the quantification of gibberellin A9 in norway spruce (Picea abies (L.) Karst.)

Quantitative estimates of gibberellin A₉ in Norway spruce extracts obtained by gas chromatography-mass spectrometry, radioimmunoassay (RIA_ and bioassay were compared after successive purifications of the extracts. The extracts were assayed in several dilutions with and without the addition of standard gibberellin A₉, thus showing the effect of extract components on the response of the assays. Radioimmunoassay produced estimates comparable to gas chromatography-mass spectrometry after one purification step by high-performance liquid chromatography. Extracts purified by polyvinylpyrrolidone-column chromatography and solvent partitioning but not high-performance liquid chromatography resulted in inaccurate RIA estimates. The performance of the RIA could be monitored by logit-log transformations of the standard curve and extract dilution curve and by calculating the slope of the standard addition curve. It was, however, not possible to correct for the interference caused by extract components by the standard addition procedure. Quantifications by Tan-ginbozu dwarf-rice bioassay were accurate, but a large and unpredictable variation makes it unsuitable for quantitative determinations.Abbreviations FW fresh weight - GA₉ gibberellin A₉ - GA₉–Me methylated GA₉ - GC-MS gas chromatography-mass spectrometry - HPLC high performance liquid chromatography - MID multiple-ion detection - RIA radioimmunoassay     

Enzyme distribution and transport activities in electrophoretically isolated fractions of the muscle sarcotubular system

A simple electrophoretic method is introduced allowing to isolate five fractions of skeletal muscle ST-system vesicles. In a previous study differences in lipid content, 3H-ouabain binding and in presence of triads in individual fractions (Lehotsky et. al. 1986) were analysed. In the present study biochemical characterization was extended, and (in accordance with previous results) major differences were observed to exist between fraction 1 and fractions 3 and 4. SDS-PAGE showed that fractions 3 and 4 were enriched in a protein with m.w. 100 kD, these fractions showing the highest specific activities of (Mg2+ + Ca2+)-ATPase and oxalate-supported Ca2+-uptake; activities of Mg2+-ATPase and surface membrane marker enzymes were the lowest in these fractions. On the other hand, in fraction 1 the highest activities of Mg2+-ATPase and marker enzymes of the surface membrane were observed together with a decreased content of the 100 kD protein and activities of Ca2+ transport. It could be concluded that the method is suitable to differentiate between relatively pure SR (fractions 3 and 4) and fractions rich in sarcolemma or T-tubules components (fractions 1 and 5).     

Septal deafferentation produces continuous rhythmic slow activity (theta) in the rat hippocampus

Hippocampal EEG was recorded in behaving rats in which the brain stem afferents to the septal region were previously damaged. In these animals rhythmic slow activity (RSA or theta) was continuously present, including drinking and immobility. The average frequency of RSA, however, was significantly higher during running (8-9 Hz) than during drinking or awake motionless state (6-8 Hz). In normal rats irregular sharp waves, rather than RSA were present during drinking and immobility. The results suggest that brain stem afferents are necessary to suppress the rhythmic firing of septal "pacemaker" cells.     

Comparative study of the transformation of various thymidine kinase-deficient human and animal cell lines with the thymidine kinase gene of the Herpes simplex virus

The comparative study of transformation of four thymidine kinase deficient cell lines (mouse mammary carcinoma cell line FS tk-; rat cell line Rat-2tk-; mouse cell line Ltk-, clone D1; human cell line 143tk-) with the thymidine kinase cloned gene of Herpes simplex virus 1 was undertaken. The differences in efficiency and optimal conditions of transformation were shown for these cell lines. The advantages and disadvantages of the cell systems examined for the use in experiments for transformation and cotransformation of cultured cells with isolated genes are discussed.     

Isolation from urine of two Serratia marcescens strains excreting a diffusible yellow pigment

Two bacterial strains excreting a yellow pigment were isolated from human urine and identified as Serratia marcescens. The pigment was produced in the late exponential and early stationary phases of growth. Minimal media supplemented with tyrosine, phenylalanine, 3,4-dihydroxyphenylacetate or tryptophan, as well as complex media, induced pigment production. UV-visible spectra of the extracted pigment had peaks characteristic of 2-hydroxy-5-carboxymethylmuconate semialdehyde, produced from meta-cleavage of 3,4-dihydroxyphenylacetate by the enzyme 3,4-dihydroxyphenylacetate 2,3-dioxygenase (EC 1.13.11.15). This enzyme was active when the bacteria were grown under conditions promoting pigment production. The kinetics and factors affecting pigment production are also reported.     

Phospholipid transfer activities in toad oocytes and developing embryos

The role of lipid transfer proteins during plasma membrane biogenesis was explored. Developing amphibia embryos were used because during their growth an active plasma membrane biosynthesis occurs together with negligible mitochondrial and endoplasmic reticulum proliferation. Sonicated vesicles, containing 14C-labeled phospholipids and 3H-labeled triolein, as donor particles and cross-linked erythrocyte ghosts as acceptor particles were used to measure phospholipid transfer activities in unfertilized oocytes and in developing embryos of the toad Bufo arenarum. Phosphatidylcholine transfer activity in pH 5.1 supernatant of unfertilized oocytes was 8-fold higher than the activity found in female toad liver supernatant, but dropped steadily after fertilization. After 20 hr of development, at the stage of late blastula, the phosphatidylcholine transfer activity had dropped 4-fold. Unfertilized oocyte supernatant exhibited phosphatidylinositol and phosphatidylethanolamine transfer activity also, but at the late blastula stage the former had dropped 18-fold and the latter was no longer detectable under our assay conditions. Our results show that fertilization does not trigger a phospholipid transport process catalyzed by lipid transfer proteins. Moreover, they imply that 75% of the phosphatidylcholine transfer activity and more than 95% of the phosphatidylinositol and phosphatidylethanolamine transfer activities present in pH 5.1 supernatants of unfertilized oocytes may not be essential for toad embryo development. Our findings do not rule out, however, that a phosphatidylcholine-specific lipid transfer protein could be required for embryo early growth.     

Skeletal biology of the Taino: a preliminary report

Preliminary data on the skeletal biology of 78 Taino skeletons belonging to Juan Dolio, an archaeological site of the Maguana province, 80 Km. east of S. Domingo, are presented. The minimum number of individuals, sex, age, stature, and morphologic and morphometric characters were determined. Dental wear and pathology of cranial and post-cranial bones were also recorded.     

Goshawk predation during winter, spring and summer in a boreal forest area of central Sweden

Predation by goshawks was studied in a central Swedish boreal forest area. Data were collected in winter (January–February) 1977-81 by tracking radio-tagged goshawks, and in the breeding season (April–July) by collecting prey remains at the nest. In the breeding season birds dominated the prey, amounting to 86% of prey number and 91% of prey biomass. Wood pigeon Columba palumbus , black grouse Tetrao tetrix , hooded crow Corvus corone cornix and jay Garrulus glandarius accounted for more than 50% of the prey animals, whereas capercaillie Tetrao urogallus and black grouse accounted for more than 50% of prey biomass. There was no functional response to black grouse density fluctuations. Every year goshawks killed significantly more females than males of both capercaillie and black grouse, due to high vulnerability of the grouse hens while laying and incubating. It was estimated that during spring and early summer goshawk predation removed 25% of the female, and 14% of the male black grouse population. In winter squirrel was the dominating prey, both in terms of number (79%) and weight (56%). The proportion of squirrel in the diet was equally high both in winters of low and high squirrel density. The high proportion of squirrel in the winterdiet, as compared to the breeding season, is believed to be due to squirrels having to accept an increased predation risk in winter, in order to feed efficiently enough.     

Is the binding of magnesium (II) to calmodulin significant? An investigation by magnesium-25 nuclear magnetic resonance

Previous reports on the interaction between calmodulin (CaM) and Mg2+ range from no binding to a binding constant of 10(4) M-1 [for a summary, see Cox, J. A., Comte, M., Malnoe, A., Berger, D., & Stein, E. A. (1984) Met. Ions Biol. Syst. 17, 215-273]. In order to resolve the controversy, we used 25Mg NMR to study the binding of Mg2+ to apo-CaM, CaM.Ca2(2)+ (in which sites III and IV are occupied by Ca2+), CaM.La2(3)+ (in which sites I and II are occupied by La3+), and the two tryptic fragments of calmodulin, TR1C (containing sites I and II of CaM) and TR2C (containing sites III and IV of CaM). In each system, a "titration set" and a "temperature set" were obtained, and the spectral data were analyzed by total band-shape analysis to calculate the association constant (Ka) and off-rate (koff). As in the case of Ca2+ binding, sites I and II and sites III and IV were treated as two sets of equivalent sites, and a Ca2+/Mg2+ competition experiment suggested that Mg2+ competes with Ca2+ for the same sites. For both CaM.Ca2(2)+ and TR1C, moderately large Ka (2000 and 3500 M-1, respectively) and moderate off-rates (koff = 2300 and 3000 s-1, respectively, at 25 degrees C) were observed. For both CaM.La2(3)+ and TR2C, binding of Mg2+ was weaker by a factor of ca. 10 (Ka = 300 and 200 M-1, respectively) while the off-rates were also moderate (koff = 3500 and 2200 s-1, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)