The effect of growth conditions on adenylate cyclase activity and virulence-related properties of Bordetella pertussis

Growth of Bordetella pertussis in Stainer & Scholte medium in which the NaCl had been replaced by one of several inorganic or organic salts resulted in a large decrease in adenylate cyclase activity, histamine-sensitizing activity and in the amounts of two cell-envelope polypeptides of Mr 28000 and 30000. Although some variation between strains was observed, there was never a case where one of these properties was lost independently of the others. Cultures in which these properties were lost had decreased amounts of extracellular cAMP when compared to NaCl-grown cultures. Adenylate cyclase activity was detected in three locations of B. pertussis cultures (extracellular, extracytoplasmic but cell-associated, and cytoplasmic). After growth in medium containing high concentrations of MgSO4, enzyme activity was decreased to a similar extent in all three locations.     

Changes in the Activity of the Maturation-Promoting Factor Are Correlated with Those of a Major Cyclic AMP and Calcium-Independent Protein Kinase During the First Mitotic Cell Cycles in the Early Starfish Embryo

Many studies suggest that MPF activation depends on protein phosphorylation or that MPF is itself a protein kinase. In the present report, cyclic variations of MPF activity have been correlated in vivo with changes in the extent of protein phosphorylation or in vitro with changes of a major protein kinase during the first cell cycles of fertilized starfish eggs. This cycling protein kinase neither requires cAMP nor Ca²⁺. Neither colchicine nor aphidicoline, which inhibits cleavage and chromosome replication respectively, was found to suppress the synchronous and cyclic variations of both MPF and protein kinase activities. Protein synthesis was found to be required for both MPF and protein kinase activities to reappear after their simultaneous drop at the time of mitotic or meiotic cleavages. Production of either MPF or protein kinase activities is not the immediate result of protein synthesis since there is a delay at each cell cycle between the time when protein synthesis is required and the time when both MPF and protein kinase activities are produced. This suggests that both MPF and protein kinase activities might involve some post-translational modification of a precursor protein synthesized during the preceeding cell cycle.     

Growth and survival of Bordetella bronchiseptica in natural waters and in buffered saline without added nutrients

Bordetella bronchiseptica showed increases in viable count when incubated in phosphate-buffered saline (PBS), in reagent-grade water, and in local lake and pond waters, all without added nutrients. Within 48 to 72 h at 37 degrees C in PBS and in lake and pond waters, stationary-phase populations of around 2.7 x 10(6) CFU/ml developed from washed B. bronchiseptica inocula of around 2 x 10(3) CFU/ml. Increases in CFU on the order of five- and eightfold, respectively, were observed in reagent-grade water and in seawater from the same sizes of inocula. The organisms remained viable for at least 3 weeks in PBS and in lake waters at 37 degrees C. The possibility that carry-over of nutrients was responsible for growth was discounted by showing serial transfer of B. bronchiseptica in PBS under conditions in which Escherichia coli tested in parallel rapidly died out.     

中国平脉树螽属五新种记述：直翅目：螽斯科：树螽亚科

本文报道中国平脉树螽属5个新种。每个新种皆有详细的形态描述和形态特征图。所有模式标本存于北京农业大学昆虫标本室。     

Changes in Abscisic Acid Content in Axis and Cotyledons of Developing Phaseolus vulgaris Embryos and their Physiological Consequences

Prevost, I. and Le Page–Degivry, M. Th. 1985. Changesin absicisic acid content in axis and cotyledons of developingPhaseolus vulgaris embryos and their physiological consequences.—J.exp. Bot. 36: 1900–1905.Changes in abscisic acid (ABA)content with time were measured in embryonic axes and in cotyledonsof Phaseolus vulgaris embryos using a radio–immunoassay.During embryogenesis, a similar pattern was observed in bothtissues: ABA increased to a maximum 29 d after an thesis, followedby a decrease as the seed matured. The level of ABA in the cotyledonswas always much higher than that in the axes. In in vitro cultures,the duration of the lag phase before germination of isolatedembryonic axes increased with ABA content. The presence of cotyledonsalways lengthened the lag phase; longer lag phases were associatedwith greater concentrations of ABA in the cotyledons. Moreoverthe presence of cotyledons stimulated the growth of seedlings. Key words: ABA distribution, embryo maturation, axis and embryo germinability     

Adenylate cyclase activity during phenotypic variation of Bordetella pertussis

During MgSO4-induced modulation of Bordetella pertussis, adenylate cyclase activity, histamine-sensitizing activity (HSA) and the major cell-envelope polypeptides with Mr 28000 and 30000 (X polypeptides) were lost synchronously at a rate which could be accounted for by a simple growth-dilution effect. MgSO4 and other compounds which induced the above phenotypic change caused little inhibition of adenylate cyclase activity. Nicotinic acid was the sole exception and at 4.1 mM-caused 60% inhibition of activity. Lysates of modulated cells, mixed with lysates of unmodulated cells, had no effect on either adenylate cyclase activity or HSA. Protein synthesis was a prerequisite for MgSO4-induced modulation and also for the reversal of this process. Exogenous cAMP and dibutyryl cAMP (5 mM) had no counteracting effect on MgSO4- or nicotinic acid-induced modulation. The concentration of MgSO4 required to induce loss of the X polypeptides (10 to 11 mM) was not altered by promoting adenylate cyclase activity by including an activator in the growth medium. In one culture containing 10 mM-MgSO4 and activator, partial loss of the X polypeptides occurred and yet the extracellular cAMP concentration was twice that of cultures without activator and where full expression of the X polypeptides occurred. [3H]cAMP-binding activity was detected in cell extracts of several strains of B. pertussis, but antiserum against purified Escherichia coli catabolite repressor protein gave no reaction with B. pertussis cell extracts. Respiration rates with amino acids were similar for modulated and unmodulated variants and an avirulent strain of B. pertussis. These results are discussed in relation to a possible causal role for adenylate cyclase in modulation of B. pertussis.     

Effects of glucose infusion on surfactant and glycogen regulation in fetal lamb lung

To investigate the increased incidence of respiratory distress syndrome (RDS) that occurs in infants of diabetic mothers (IDM) with poor maternal glucose homeostasis, we infused glucose intravenously at a rate of 14 +/- 2 (SD) mg.kg-1.min-1 into eight twin and four singleton chronically catheterized fetal lambs from 112 days (0.77) gestation onward. Twelve catheterized and seven uncatheterized fetuses served as controls, including the eight twins of the glucose-treated fetuses. Glucose infusion resulted in a twofold elevation in fetal serum glucose levels and a 2.2-fold elevation in fetal serum insulin levels. Before 113 days (0.9) gestation, pulmonary disaturated phosphatidylcholine (DSPC) content was 1.5-fold higher in the glucose-infused fetuses than in the controls. However, after 0.9 gestation, pulmonary DSPC content increased 2.2-fold in the controls but did not increase significantly in the glucose-infused fetuses. In addition, the DSPC content of lung lavage was 5.0-fold higher in the controls and lung stability to air inflation was 2.0-fold greater and to deflation was 2.2-fold greater than in the glucose-infused fetuses. Pulmonary adenosine 3',5'-cyclic monophosphate-dependent protein kinase activity was also 1.5-fold higher, and pulmonary protein kinase C activity was 1.3-fold higher in the controls than in the glucose-infused fetuses. In contrast, glucose infusion was associated with a 1.8-fold increase in pulmonary glycogen content and with increased activities of glycogen phosphorylase kinase and glycogen phosphorylase. We conclude that the effects of chronic glucose infusion on fetal lamb lung DSPC and lung stability are compatible with a predisposition of the fetus to develop RDS.(ABSTRACT TRUNCATED AT 250 WORDS)