Cutaneous pythiosis in a goat.

Pythiosis is reported for the first time in a goat. The affected goat had daily access to an aquatic environment and had developed an ulcerative lesion on the skin of the left hindlimb. Microscopically, there were dermal pyogranulomas with 'negatively stained' hyphae, which were identified immunohistochemically as Pythium insidiosum.

Nasal and cutaneous aspergillosis in a goat.

Nasal and cutaneous aspergillosis is reported in an adult goat. The clinical signs were severe respiratory distress due to partial nasal obstruction, bilateral mucopurulent nasal discharge, skin nodules on the ears and dorsal nasal region and focal depigmentation of the ventral commissure of the right nostril. At necropsy examination, sagittal sectioning of the head revealed a yellow irregular mass extending from the nasal vestibule to the frontal portion of the nasal cavity. Microscopically, there was pyogranulomatous rhinitis and dermatitis, with numerous intralesional periodic acid-Schiff-positive fungal hyphae morphologically suggestive of Aspergillus spp. Aspergillus niger was isolated by microbiological examination.

Role of the PI3K regulatory subunit in the control of actin organization and cell migration.

Cell migration represents an important cellular response that utilizes cytoskeletal reorganization as its driving force. Here, we describe a new signaling cascade linking PDGF receptor stimulation to actin rearrangements and cell migration. We demonstrate that PDGF activates Cdc42 and its downstream effector N-WASP to mediate filopodia formation, actin stress fiber disassembly, and a reduction in focal adhesion complexes. Induction of the Cdc42 pathway is independent of phosphoinositide 3-kinase (PI3K) enzymatic activity, but it is dependent on the p85alpha regulatory subunit of PI3K. Finally, data are provided showing that activation of this pathway is required for PDGF-induced cell migration on collagen. These observations show the essential role of the PI3K regulatory subunit p85alpha in controlling PDGF receptor-induced cytoskeletal changes and cell migration, illustrating a novel signaling pathway that links receptor stimulation at the cell membrane with actin dynamics.

Chromatin fluorescence by pyronin staining.

Human, chicken and mouse cells from different tissues show a bright red-orange fluorescence of the chromatin after staining with pyronin Y. The possibility that intercalation of the dye into double helical nucleic acids accounts for this fluorescence pattern is briefly discussed.