Pollen carryover,nectar rewards,and pollinator behavior with special reference to Diervilla lonicera

Summary Pollen carryover was measured in three species of bumble bee pollinated plants by counting the numbers of foreign grains applied to the stigmas of a series of flowers by bumble bees. Deposition declined with the number of flowers visited in a roughly exponential fashion; most grains were deposited on the first few flowers, but some grains went much farther, the maximum carryover being 54 flowers. Variation in deposition was very high. In Diervilla lonicera, bees desposited significantly more grains on flowers which contained large amounts of nectar than on drained flowers. The implications are discussed in terms of plant strategies for optimizing pollination.     

Mutagenic activity of Fusarium moniliforme isolates in the Salmonella typhimurium assay.

A total of 33 isolates of Fusarium moniliforme from several food or feed crops were grown on sterile cracked corn, and chloroform-isopropanol extracts were assayed for mutagenic activity in the Salmonella typhimurium-microsome system by using tester strain TA98 or TA100 or both. Extracts of 21 (64%) of the isolates assayed against TA100 were mutagenic. Activities of seven of these extracts were increased markedly with incorporation of the liver homogenate (S-9) into the assay. Seven (33%) of the isolates assayed against TA98 were weakly active, with the liver homogenate having little effect on reversion rates.     

Flunisolide nasal spray for perennial rhinitis in children.

Twenty-seven children with perennial rhinitis entered a double-blind cross-over study comparing nasal sprays of flunisolide---a new topical corticosteroid---and placebo. Symptoms were assessed over two consecutive monthly periods with each treatment. Weekly diary cards, monthly clinical assessments, and end-of-trial preferences all favoured the active drug. At the end of the trial 20 patients preferred the treatment month with flunisolide, four preferred the placebo month, and two rated the periods equally. Side effects were mild, the commonest being transient nasal stinging. Seventeen children who derived benefit from flunisolide continued with the treatment for a six-month open-study period. Many reduced the dosage from three times to twice or once daily without losing benefit. The effect of flunisolide on the pituitary-adrenal axis was assessed in seven children by measuring the 0900 blood cortisol concentrations at two-month intervals over the six months. No effect was observed. The results show that flunisolide is effective and safe for the treatment and prophylaxis of perennial rhinitis in children.     

Study of Candida ingens grown on the supernatant derived from the anaerobic fermentation of monogastric animal wastes.

A pellicle-forming yeast, identified as Candida ingens, was found to grow on substrates derived from the anerobic fermentation of monogastric animal wastes. The organism used volatile fatty acids C2 to C6 and ammonia nitrogen. It had a preferential uptake of the acids in increasing order of molecular weight, removing 90% of the total titratable volatile acid. The nonwrinkled pellicle had a doubling time of 3.2 h, and the doubling time of the wrinkled pellicle was 4.2 h. Proximate amino acid and nucleic acid analyses suggested that the organism might be acceptable as a source of single cell protein. Its vitamin B group content compared favorably with that of other yeasts. It contained 6% calcium and 7% phosphorus. It could be useful in removing these minerals from effluents as well as in providing them as nutrients in livestock rations.     

An ultrastructural study of two forms of chilling-induced injury to the rind of grapefruit (Citrus paradisi, Macfed).

The ultrastructural manifestations of storage chilling-injury and concentric ring stipple indicate that the two types of injury are similar in some respects and different in others.The low temperature storage-induced injury involves the epidermal cells and several layers of epicarpal cells below. It is manifested as an increase in lipid material in the cytoplasm and vacuole and in eventual degradation and collapse of the cytoplasm. The field injury, concentric ring stipple, apparently involves primarily the epidermal cells which become extremely electron dense. The epicarp cells of the injured region do not show extensive damage but do exhibit increased lipid accumulation. This accumulation of lipid is a phenomenon common to both types of injury and may be indicative of an altered metabolism due to the low temperatures. The apparent loss of organization and compartmentation in the chilling injury is also suggestive of membrane degradation.The storage chilling-injury occurs after exposure to low temperatures for several weeks, whereas the concentric ring stipple is evidently induced by an exposure in the field for only a few hours. The ultrastructural differences observed in these two injuries, therefore, may be due to the different time- and stress- factors involved.     

Prophage Induction in Escherichia coli (Lambda) by N-Nitrosamines

Carcinogenic N-nitrosamines were tested for their ability to induce λ in a lysogenic strain of Escherichia coli K-12 (58-161 F⁺). Dimethylnitrosamine, di-n-propylnitrosamine, methyl-n-propylnitrosamine, and N-nitrosopiperidine were shown to be inducers of prophage.     

Nuclear phosphoprotein kinase activities in normal and neoplastic tissues.

Nuclear phosphoprotein kinases from normal rat liver and transplantable neoplasms were fractionated and compared. A phosphoprotein kinase fraction activated by Mn2+ was found to be present only in the neoplasms. This nuclear protein kinase phosphorylated nuclear proteins represented by one major and several minor bands as determined by polyacrylamide gel electrophoresis (M approximately 50,000).     

Unstable generalized transduction in Achromobacter.

Six auxotrophic markers of a halotolerant collagenolytic strain of Achromobacter were transduced by four alpha hages. Abortive transduction was also demonstrated. The generalized transduction system is unusual as the transductants were unstable, characteristic of transduction by lysogeny. The Achromobacter strain is a cryptic lysogen for alpha and purified transductants were either sensitive or resistant to alpha. Purified clones from four resistant transductants and one sensitive transductant liberated phage spontaneously. The host ranges of these spontaneous phage differed from that of the alpha phage used for the transduction experiment. Some initially resistant transductants became simi-sensitive to alpha (efficiency to plating) e.o.p. (10minus-1 to 10minus-2) after repeated cloning.     

Specific inhibitors of methane oxidation in Methylosinus trichosporium

Methane oxidation by washed cell suspensions of Methylosinus trichosporium OB3B was selectively inhibited by 25 compounds, including metal binding components such as carbon monoxide (85% O₂: 15% CO), KCN (10^-6 M), αα′-dipyridyl (10^-4 M), 8-quinolinol (10^-4 M), thiosemicarbazide (10^-5 M), thiourea (10^-5 M), hydroxylamine (10^-4 M), histidine (10^-2 M), British Anti-Lewisite (5x10^-3 M), and miscellaneous known inhibitors of other oxygenases. A role for copper in the methane oxygenase system was suggested by the pattern of inhibition and relief of inhibition by added metal ions.