PubMed · 942221
The source did not provide an abstract. Follow the original record for more information.
Explore connections, maps & timelines
R Binder. 1976. Letter: Hyperpigmentation caused by a fungicide.. https://doi.org/10.1001/archderm.1976.01630300076018
Cite the original work for its findings. Save a collection to share your selection of sources.
KEEP EXPLORING
Microtubules (MTs) are often organized by a nucleus-associated MT organizing center (MTOC). In addition, in neurons and epithelial cells, motor-based transport of assembled MTs determines the polarity of the MT array. Here, we show that MT motility participates in MT organization in the fungus Ustilago maydis. In budding cells, most MTs are nucleated by three to six small and motile gamma-tubulin-containing MTOCs at the boundary of mother and daughter cell, which results in a polarized MT array. In addition, free MTs and MTOCs move rapidly throughout the cytoplasm. Disruption of MTs with benomyl and subsequent washout led to an equal distribution of the MTOC and random formation of highly motile and randomly oriented MTs throughout the cytoplasm. Within 3 min after washout, MTOCs returned to the neck region and the polarized MT array was reestablished. MT motility and polarity of the MT array was lost in dynein mutants, indicating that dynein-based transport of MTs and MTOCs polarizes the MT cytoskeleton. Observation of green fluorescent protein-tagged dynein indicated that this is achieved by off-loading dynein from the plus-ends of motile MTs. We propose that MT organization in U. maydis involves dynein-mediated motility of MTs and nucleation sites.
The aim of this study was to investigate permeation of the fungicide benomyl at its highest field application concentration (0.70 mg/mL) in Benlate 50 WP aqueous solution (1.4 mg/mL) through two types of unsupported and unlined nitrile gloves--a disposable latex glove (Safeskin) and an industrial chemical-resistant glove (Solvex)--using an American Society for Testing and Materials (ATSM)-type permeation cell with isopropanol collection medium. The permeation cell was contained in a moving-tray water bath at 30.0 degrees C +/- 0.5 degrees C. The collection medium was evaporated and the residue derivatized with an optimized method (2,3,4,5,6-pentafluoro)benzyl bromide to form the disubstituted derivative of carbendazim (CARB), CARB.2PFB. The latter in isooctane was then quantified by gas chromatography- 63Ni-electron capture detection (GC-ECD) by the internal standard method. GC-ECD, GC-mass spectrometry (GC-MS), and reflectance infrared investigations showed that little degradation of benomyl occurred in the challenge solution of aqueous Benlate during an 8-hour exposure period. Benomyl was collected as a mixture of CARB and benomyl as shown by the presence of a diagnostic chromatographic peak identified by GC-MS. The amounts permeated during the same time period were always higher for Safeskin than for Solvex gloves, with the latter being approximately 18 times more protective than the former after 8 hours of continuous exposure. Although the Solvex gloves were safe to wear at least for 4 hours and for almost 8 hours, the ASTM breakthrough threshold was used as reference and thus ignored carcinogenic effects. Reflectance infrared investigations detected benomyl and CARB on the glove challenge surface after drying and confirmed that the cleaned glove surfaces after permeation experiments did not differ in infrared reflectance spectra from the corresponding surfaces just before the permeation experiments.
In budding yeast, phosphoinositide-specific phospholipase C (Plc1p encoded by PLC1 gene) is important for function of kinetochores. Deletion of PLC1 results in benomyl sensitivity, alterations in chromatin structure of centromeres, mitotic delay, and a higher frequency of chromosome loss. Here we intended to utilize benomyl sensitivity as a phenotype that would allow us to identify genes that are important for kinetochore function and are downstream of Plc1p. However, our screen identified SIN4, encoding a component of the Mediator complex of RNA polymerase II. Deletion of SIN4 gene (sin4Delta) does not suppress benomyl sensitivity of plc1Delta cells by improving the function of kinetochores. Instead, benomyl sensitivity of plc1Delta cells is caused by a defect in expression of FLR1, and the suppression of benomyl sensitivity in plc1Delta sin4Delta cells occurs by derepression of FLR1 transcription. FLR1 encodes a plasma membrane transporter that mediates resistance to benomyl. Several other mutations in the Mediator complex also result in significant derepression of FLR1 and greatly increased resistance to benomyl. Thus, benomyl sensitivity is not a phenotype exclusively associated with mitotic spindle defect. These results demonstrate that in addition to promoter-specific transcription factors that are components of the pleiotropic drug resistance network, expression of the membrane transporters can be regulated by Plc1p, a component of a signal transduction pathway, and by Mediator, a general transcription factor. The results thus suggest another layer of complexity in regulation of pleiotropic drug resistance.