A range of fluorescent viability dyes were used in conjunction with flow cytometry to rapidly enumerate viable bacteria from freshwater environments. Optimal labelling was achieved by using carboxyfluorescein diacetate or chemchrome B with a detergent-mediated permeabilization step. The viable bacterial count under optimal conditions was 7% in oligotrophic lake water and 75% in polluted river w...

The fluorescein diacetate-ethidium bromide (FDA/EB) staining method for determining the viability of mycobacterial cells reported by Kvach and Veras was modified for applying the method to Mycobacterium leprae and Mycobacterium lepraemurium. Our method clearly differentiated green-stained cells from red-orange ones with either mycobacterial species and permitted their original fluorescence for ...

The use of iodobenzene diacetate and iodine under photolytic conditions provides and efficient method for the oxidative cyclization of spiroacetals bearing an hydroxyalkyl side chain to bis-spiroacetals. An overview is provided of the use of this reaction for the synthesis of several bis-spiroacetal containing natural products such as the polyether antibiotics salinomycin and CP44,161 and the s...

A new method for the ring expansion of cyclic diols is described. Using improved conditions for the ruthenium(0) catalyzed cycloaddition of cyclic 1,2-diols with 1,3-dienes, fused [n.4.0] bicycles (n = 3-6) are formed, which upon exposure to iodosobenzene diacetate engage in oxidative cleavage to form the 9-12 membered rings .

A new eunicellin diterpenoid, cladieunicellin I (1), and a new natural eunicellin, litophynin I diacetate (2), were isolated from a Formosan soft coral identified as Cladiella sp. The structures of eunicellins 1 and 2 were elucidated by spectroscopic methods and by comparison of the spectral data with those of related analogues. Eunicellin 1 exhibited significant cytotoxicity toward the DLD-1 h...

As part of our search for bioactive compounds from plant biodiversity, 29 withanolides (1, 3-6, 9, 12-18, and 20-35) were recently isolated from three members of the Solanaceae: Physalis longifolia, Vassobia breviflora, and Withania somnifera. Six derivatives (2, 7, 8, 10, 11, and 19) were prepared from these naturally occurring withanolides. All compounds (1-35) were evaluated for in vitro ant...

In order to identify a substance by means of paper chromatography it is highly desirable to compare the running rates of as many of its derivatives as possible with the running rates of comparable derivatives of known substances. When only microgram quantities are available, the preparation of derivatives in good yield often presents a problem. It is the primary purpose of this communication to...