Effects of acid irrigation and liming on two clones of Norway spruce

Summary The effect of acid irrigation on the growth of rooted cuttings ofPicea abies (L.) Karst, was investigated in a pot experiment lasting 3 years. It involved two clones of Norway spruce, H 253 Bogstad I and H 254 Bogstad II. Irrigation water of pH 5.4, 4.0, 3.0 and 2.5 was used. Liming was included in the experiment.After the experimental period, the plants of all treatments were growing reasonably well. However, those plants irrigated at pH 2.5 were slightly discoloured. The plant mortality was only 3% throughout the experiment, and was not connected to acid irrigation. The limiting growth factor was N. All other nutrient elements measured in the plants were close to optimal concentration. Plants irrigated at pH 2.5, and to some extent at pH 3, contained excessively high concentrations of Al, t-S and SO₄. The total amount of Ca, Fe and Mn taken up by the plants decreased with increasing soil acidity. The increased growth of clone H 254 relative to H 253, produces a corresponding impression on soil characteristics. Soil acidity is governed by acid irrigation and CaCO₃ application, but the clonal effects are also of importance. Norway spruce appears to be tolerant to Al concentrations as high as 50 mmol/kg in the needles.     

Brugia pahangi: Feeding and nutrient uptake in vitro and in vivo

Incubation in vitro of adult Brugia pahangi in an apparatus which permitted the separate exposure of the anterior, middle, or posterior region of the worms to medium-containing radioactively labeled d-glucose, l-leucine, and adenosine has provided evidence that these materials are taken up in physiologically significant amounts by a transcuticular route. No evidence for an oral ingestion of materials has been obtained from worms in vitro, but in vivo an oral uptake of Trypan blue has been demonstrated. The ultrastructure and cytochemical staining reactions for nonspecific esterase, acid phosphatase (EC-3.1.3.2), and leucine naphthylamidase of the gut and body wall are described.     

An ultrastructural and cytochemical study of the interaction between latex particles and the haemocytes of the wax moth Galleria mellonella in vitro

Summary The plasmatocytes are the major phagocytic blood-cell type in the haemolymph of the wax-moth, Galleria mellonella. In the present study, these cells were allowed to attach to tissue culture dishes for 1 h, rinsed and then incubated with latex beads for up to 72 h. These cells were then fixed for routine transmission electron microscopy and acid phosphatase cytochemistry. Intracellular latex particles were found in tight, ill-defined phagosomes, which were often clearly associated with the Golgi complexes of the plasmatocytes. Fusion of both primary lysosomes and multivesicular bodies with the phagosomes occasionally occurred and this resulted in the accumulation of an acid phosphatase positive reaction product around the test particles. Subsequent experiments showed that this acid phosphatase activity was mainly associated with the primary lysosomes. The results of the lysosome/latex interactions are compared with those obtained from similar studies on the digestive mechanisms in other phagocytes.We are grateful to Professor E.W. Knight-Jones in whose department this work was carried out and to Mrs. M. Colley for help in insect rearing. This work was supported by grants from the Royal Society and the Science Research Council (B/73/0176. and B/RG/2286.0)     

The fine structural localization of acid phosphatase in pore cells of embryonic and newly hatched Deroceras reticulatum (Pulmonata: Stylommatophora)

Summary The fine structure of the pore cells in pre- and post-hatched Deroceras reticulatum is described. The cells have been divided into three main types on morphological grounds, one type being particularly rich in glycogen. Certain pore cells contain haemocyanin granules in grooves below cytoplasmic tongues, and in characteristic double-membrane-bounded vesicles within dilated cisternae of rough endoplasmic reticulum, as well as in other identified areas. All types of pore cells show fine fibres reminiscent of collagen associated with the basal lamina and pore complexes.In addition to acid phosphatase activity in lysosomes and Golgi elements, intra- and extracisternal activity has been demonstrated in association with the rough endoplasmic reticulum. The intracisternal activity is in close proximity to the Golgi apparatus and may represent enzyme that is about to enter the GERL system. Extracisternal activity may be associated with cellular lysis and death, or may represent local areas of degradation leading to cytodifferentiation. Remnants of lysed pore cells appear to be taken up by connective tissue amoebocytes.The authors wish to acknowledge the financial support of the Agricultural Research Council (G.B.) Grant No. AG 72/21, the photographic assistance of Mr. Nigel Green, and some technical assistance from Miss Jane Morgans     

Induction of synchronous differentiation (encystment) in Physarum polycephalum myxamoebae

Encystment of Physarum polycephalum myxamoebae, grown under nearly identical physiological conditions as plasmodia is induced by transfer to a salts medium containing 0.5 M mannitol or mannose. After 24 h induction approximately 50% of amoebae had differentiated to cells which were identified to be young cysts by light and electron microscopy. Several other polyols, sugars, biogenic amines, and a starvation period from 24 h to one week caused no reproducible cyst formation. In contrast to the formation of dormant forms in the plasmodial stage of the life cycle, the induction of cysts and their germination to amoebae are not inhibited neither by actinomycin C nor by cycloheximide. In addition, the isoenzyme spectra of aminopeptidases and acid proteases remain nearly identical in growing and differentiating amoebae.Abbreviations SD semi-defined BSS basal salts solution The investigation is a part of the Ph. D. thesis of A. Haars, Göttingen, 1976     

Coenzymes as fossils of an earlier metabolic state

Summary A metabolic system composed of nucleic acid enzymes is proposed to have existed prior to the evolution of ribosomal protein synthesis. Vestiges of these nucleic acid enzymes persist in contemporary coenzymes. This proposal rationalizes the fact that many coenzymes are nucleotides or heterocyclic bases which could be derived from nucleotides.     

Production of gluconic acid and 2-ketogluconic acid by Klebsiella aerogenes NCTC 418

2-Ketogluconic acid and, to a lesser extent, gluconic acid were found to be major products of glucose catabolism by phosphate-limited cultures of Klebsiella aerogenes NCTC 418, and together accounted for up to 46% of the glucose carbon that was metabolized.Although the concentrations of both acids increased sub-stantially at low growth rates, their specific rates of synthesis decreased markedly, as did the proportion of glucose converted into these products.Determination of the affinity constant, for glucose, of phosphate-limited organisms showed it to be not significantly different from that of glucose-limited organisms (K _s 50 M), indicative of the phosphotransferase uptake system. And since these organisms possessed an active glucose 6-phosphate dehydrogenase, and had no detectable glucose dehydrogenase activity, it was concluded that gluconic acid and 2-ketogluconic acid arose from their corresponding phosphorylated metabolites, and not directly from glucose.     

Control of Redox Balance by the Stringent Response Regulatory Protein Promotes Antioxidant Defenses of Salmonella

We report herein a critical role for the stringent response regulatory DnaK suppressor protein (DksA) in the coordination of antioxidant defenses. DksA helps fine-tune the expression of glutathione biosynthetic genes and discrete steps in the pentose phosphate pathway and tricarboxylic acid cycle that are associated with the generation of reducing power. Control of NAD(P)H/NAD(P)⁺ redox balance by DksA fuels downstream antioxidant enzymatic systems in nutritionally starving Salmonella. Conditional expression of the glucose-6-phosphate dehydrogenase-encoding gene zwf, shown here to be under DksA control, increases both the NADPH pool and antioxidant defenses of dksA mutant Salmonella. The DksA-mediated coordination of redox balance boosts the antioxidant defenses of stationary phase bacteria. Not only does DksA increase resistance of Salmonella against hydrogen peroxide (H₂O₂), but it also promotes fitness of this intracellular pathogen when exposed to oxyradicals produced by the NADPH phagocyte oxidase in an acute model of infection. Given the role of DksA in the adjustment of gene expression in most bacteria undergoing nutritional deprivation, our findings raise the possibility that the control of central metabolic pathways by this regulatory protein maintains redox homeostasis essential for antioxidant defenses in phylogenetically diverse bacterial species.     

A novel aggregation-induced emission fluorescent probe for nucleic acid detection and its applications in cell imaging

A new kind of aggregation-induced emission compound was synthesized and used as the probe of nucleic acid. The characterization of this compound was studied. Both the RNA and DNA were detected by using this probe. And the detection scope of DNA and RNA was different. We researched the selectivity of our probe in double and single strand DNA sequences. The visualization of gel electrophoresis and the cell nucleus imaging were researched as well. Compared with the traditional nucleus dye Hoechst 33258, our probe also has the potential to be nucleus dye. And the cell toxicity was well performed by MTT assays.