Establishment and maintenance of nuclear position during zoospore formation in allomyces macrogynus: roles of the cytoskeleton

The involvement of the microtubule (MT) and actin microfilament (MF) cytoskeletons in establishing nuclear positions during zoosporogenesis in Allomyces macrogynus was assessed using selective cytoskeletal disrupting treatments and documented with light microscopy. These experiments were coupled with low-speed centrifugation studies to determine the degree to which cytoskeletal elements anchor nuclear position. At the onset of zoospore formation, nuclei were positioned only in cortical cytoplasmic regions of the zoosporangia (ZS). Immunofluorescence microscopy revealed that MTs primarily emanated from centrosomal regions into the surrounding cytoplasm at this stage. During delimitation of the cytoplasm into individual uninucleate zoospores, nuclei migrated from cortical regions to become distributed throughout the cytoplasm. Coincident with nuclear migrations, MTs were primarily organized at and emanated from nuclear surfaces, forming extensive perinuclear arrays. Nuclear migrations were suppressed in ZS induced to sporulate in the presence of cytochalasin D, an actin MF inhibiting compound. Disruption of MTs with nocodazole did not block nuclear migrations, although resultant nuclear spacing was irregular. Centrifugation treatments of control and drug-treated ZS demonstrated that nuclear positions were stabilized by perinuclear MT arrays. The results indicate that nuclear motility in ZS of A. macrogynus is the result of an actin-based system while perinuclear MTs arrays function to establish and fix nuclear position during zoospore formation. Copyright 1998 Academic Press.     

A review of curcumin as a biological stain and as a self-visualizing pharmaceutical agent

Curcumin has been widely used to color textiles but, unlike other natural dyes such as hematoxylin or saffron, it rarely has been discussed as a biological stain. Aspects of the physicochemistry of curcumin relevant to biological staining and self-visualization, i.e., its acidic properties, lipophilicity, metal and pseudometal complexes, and optical properties, are summarized briefly here. Reports of staining of non-living biological specimens in sections and smears, both fixed and unfixed, including specimens embedded in resin, are summarized here. Staining of amyloid, boron and chromatin are outlined and possible reaction mechanisms discussed. Use of curcumin as a vital stain also is described, both in cultured monolayers and in whole organisms. Staining mechanisms are considered especially for the selective uptake of curcumin into cancer cells. Staining with curcumin labeled nanoparticles is discussed. Toxicity and safety issues associated with the dye also are presented.     

News from the Biological Stain Commission No. 15

In the 15^th issue of News from the Biological Stain Commission (BSC), under the heading of Regulatory affairs, the Biological Stain Commission’s International Affairs Committee presents information from the plenary meetings of the International Standards Organization ISO/TC 212 Clinical laboratory testing and in vitro diagnostic test systems held on August 22–24, 2012 in Berlin, Germany. An additional discussion of the use of food dyes in India also is included.     

Accomplishments of the Trustees and laboratory staff of the Biological Stain Commission, 2002–2013

During the 12 years from 2002 to 2013, the Trustees and laboratory personnel of the Biological Stain Commission (BSC) can claim many accomplishments. These accomplishments are itemized under 11 categories: continuous publication of the official journal, Biotechnic & Histochemistry; production of four special issues of Biotechnic & Histochemistry devoted to specific dyes or stains; standardization of staining and dye purity; mechanisms of staining and prediction of dye behavior; publication of books or book chapters; effects of fixation and processing on staining; cancer research; immunohistochemistry; BSC Laboratory activities; miscellaneous publications; and administrative accomplishments.     

What regulates secretion of non-stored proteins by eukaryotic cells?

Protein secretion is conventionally viewed as taking place by either of two cellular routes, a regulated pathway, involving external stimuli and secretory granules, and a presumptive ‘constitutive’ pathway, which does not involve hormonal or neuronal stimuli or the production of secretory granules. The evidence reviewed here strongly suggests that there are post-synthesis rate-limiting steps for many proteins released by the ‘constitutive’ pathway and, hence, that regulation in some sense is involved here too. The nature of these rate-limiting determinants and events is discussed.     

Progress in treatment of ANCA-associated vasculitis

Autoantibodies to neutrophil cytoplasmic antigen-associated vasculitis (AAV) is characterised by inflammation of blood vessels. The introduction of immunosuppressive therapy with glucocorticoids and cyclophosphamide transformed AAV from a fatal condition to a largely treatable condition. Over the past 30 years, considerable progress has been made refining immunosuppressive regimens with a focus on minimising toxicity. There is, however, a high unmet need in the treatment of AAV. A proportion of patients are refractory to current therapies; 50% experience a relapse within 5 years and treatment toxicity contributes to mortality and chronic disability. As knowledge of the pathogenesis of vasculitis grows, it is mirrored by the availability of biological agents, which herald a revolution in the treatment of vasculitis. Lymphocyte-targeted and cytokine-targeted agents have been evaluated for the treatment of AAV and are entering the routine therapeutic arena with the potential to improve patient outcomes. As rare diseases, treatment advances in vasculitis depend on international collaborative research networks both to establish an evidence base for newer agents and to develop recommendations for patient management.