The neutral red uptake assay is a cell viability assay that allows in vitro quantification of xenobiotic-induced cytotoxicity. The assay relies on the ability of living cells to incorporate and bind neutral red, a weak cationic dye, in lysosomes. As such, cytotoxicity is expressed as a concentration-dependent reduction of the uptake of neutral red after exposure to the xenobiotic under investig...

1. Phenol red and neutral red are excreted by the perfused frog's kidney by different routes. 2. Phenol red is excreted chiefly through the glomerulus, neutral red through the tubules. 3. Some slight excretion of each of these dyes by the converse mechanism is possible, though there is no evidence in our experiments that necessitates such a conclusion. 4. The importance of methods leading to th...

Application of eucaryote inhibitors to the estimation of production and grazing mortality of bacterioplankton was evaluated. Exposure to a range of concentrations of thiram, cycloheximide, and neutral red (0.4 to 210, 36 to 1,777, 4 to 346 ,uM, respectively) was 98 to 100% effective at inhibiting growth of a chrysomonad in culture. Exposure to colchicine and griseofulvin (50 to 1,000 ,uM for bo...

To test the hypothesis that periodic signals and chemotaxis direct later morphogenesis in Dictyostelium discoideum, we investigated cell behavior and cell movement in slugs. Trails of neutral red-stained prestalk and anterior-like cells were recorded by high-resolution digital image processing. Neutral red-stained anterior-like cells in the prespore zone of slugs move straight forward in the di...

Dermatomycosis is prevalent worldwide. Discrepancy between microscopic examination and culture findings can create problems in the diagnosis of this common infection. In this study, samples from 60 patients were processed after trypsin treatment and examined by neutral red staining to distinguish viable and non-viable fungal elements. The trypsin treatment method was compared with standard labo...

Limulus ventral photoreceptors are vitally stained by neutral red. In other systems such staining has been correlated with the presence of monoamines or neuropeptides. The stained cellular components in ventral photoreceptors are clusters of small ovoids which have been identified as residual bodies. These structures are unlikely candidates for monoamine or neuropeptide synthesis or storage sit...

The fabrication of silk-based membranes that are stable, optically transparent and reusable is yet to be achieved. To address this bottleneck we have developed a method to produce transparent chromogenic silk patches that are optically responsive to pH. The patches were produced by blending regenerated silk fibroin (RSF), Laponite RD (nano clay) and the organic dyes neutral red and Thionine ace...

A simple, precise and accurate method is proposed for rapid determination of trace amounts of hydroxylamine based on the reaction of hydroxylamine with iodate in acidic media. The reaction of neutral red by the produced nitrite ion was used to monitor the reaction spectrophotometrically at 525 nm by a fixed time method. Hydroxylamine in the range of 0.0400-1.200 microg mL(-1) could be determine...

The ultrafast excited state dynamics of the fluorescent protein Kaede has been investigated by employing time resolved fluorescence and transient absorption. Upon irradiation of its neutral state, the protein undergoes an efficient conversion to a state that fluoresces at longer wavelengths. The molecular basis of the photoconversion involves an expansion of the chromophore π-conjugation by for...

When neutral red is added to the liquid medium in tissue cultures, more dye is taken up by healthy cells than by damaged cells. This forms the basis of a method for assessing the relative extent of cell damage in different cultures, the amounts of bound dye being determined directly by inspection of the stained cell sheets, or indirectly by estimating extracted dye colorimetrically. This proced...