Microscope-based multiparameter laser scanning cytometer yielding data comparable to flow cytometry data

We describe a computer-controlled 10 microns spot size laser scanning cytometer for making multiple wavelength fluorescence and scatter measurements of unconstrained cells on a surface such as a microscope slide. Designated areas of slides placed on a microscope stage are automatically scanned, and cells which generate above-threshold scatter or fluorescence values are found and individually processed to determine a list of measurement parameters. For each fluorescence or scatter measurement parameter, this list contains the integrated and peak values and bit pattern images of a scan window centered on the cell. The measurement time, the position of the cell on the slide, and two segmentation indices are also included in the list. Measurement time, cell position, and properties derived from the bit patterns are used interchangeably with integrated or peak measurement values as coordinates of multiproperty displays. Cells may be selected for counting, data display in various forms, or visual observation based on their meeting complex criteria among a chain of two property screens. Cells with selected properties may be viewed during an experiment or retrospectively. A designated specimen field may be repeatedly remeasured to perform kinetic cell studies. An argon ion and a HeNe- based laser instrument have been constructed and software has been written and evaluated with the specific goal of increasing the precision of propidium iodide-stained cellular DNA measurements. Some of the capabilities of the instrument and its current performance are described.     

Marine polyprenylated hydroquinones, quinones, and chromenols with inhibitory effects on leukotriene formation

A series of polyprenylated hydroquinones, quinones, and chromenols were isolated from the extracts of the marine sponge Ircinia spinosula and the brown alga Taonia atomaria, which gave rise to the constituents 1-4 and 5-8, respectively. Compounds 1, 2, 6, and 7 are new natural products, which were fully characterized. Their anti-inflammatory activities in terms of leukotriene formation were evaluated in an in vitro assay with pork leukocytes. The new hydroxylated compound, 2'-[28-hydroxy]heptaprenyl-1',4'-hydroquinone (= 2-[(2E,6E,10E,14E,18Z,22E)-19-(hydroxymethyl)-3,7,11,15,23,27-hexamethyloctacosa-2,6,10,14,18,22,26-heptaen-1-yl]benzene-1,4-diol; 1), the known tetraprenyl benzoquinone sargaquinone (5), and the known polyprenyl chromenols 3 and 4 exhibited the highest anti-inflammatory activities, with IC50 values of 1.9-9.4 microM (Table 3). Potential structure-activity relationships (SAR) are discussed.     

Isolated Phosphate-Solubilizing Soil Bacteria Promotes In vitro Growth of Solanum tuberosum L.

The capacity of four bacterial strains isolated from productive soil potato fields to solubilize tricalcium phosphate on Pikovskaya agar or in a liquid medium was evaluated. A bacterial strain was selected to evaluate in vitro capacity of plant-growth promotion on Solanum tuberosum L. culture. Bacterial strain A3 showed the highest value of phosphate solubilization, reaching a 20 mm-diameter halo and a concentration of 350 mg/l on agar and in a liquid medium, respectively. Bacterial strain A3 was identified by 16S rDNA analysis as Bacillus pumilus with 98% identity; therefore, it is the first report for Bacillus pumilus as phosphate solubilizer. Plant-growth promotion assayed by in vitro culture of potato microplants showed that the addition of bacterial strain A3 increased root and stems length after 28 days. It significantly increased stem length by 79.3%, and duplicated the fresh weight of control microplants. In this paper, results reported regarding phosphorus solubilization and growth promotion under in vitro conditions represent a step forward in the use of innocuous bacterial strain biofertilizer on potato field cultures.Key words: Bacillus sp., phosphorus soluble, Pikovskaya agar, potato rhizosphere, plant growth promoting rhizobacteria