Isolation and characterisation of cycloheximide sensitive mutants of Aspergillus nidulans

Aspergillus nidulans is a non-pathogenic fungus with well-developed genetics which provides an excellent model system for studying different aspects of drug resistance in filamentous fungi. As a preliminary step to characterizing genes that confer pleiotropic drug resistance in Aspergillus, we isolated cycloheximide-sensitive mutants of A. nidulans, which is normally resistant to this: drug. The rationale for this approach is to identify gents whose products are important for drug resistance by analysing mutations that alter the resistance/sensitivity status of the cell. Fifteen cycloheximide-sensitive (named scy for sensitive to cycloheximide) mutants of A, nidulans were isolated and genetically characterised. Each scy mutant was crossed with the wild-type strain and five of the crosses gave 50% cycloheximide-sensitive progeny suggesting that they carry a single mutation required for cycloheximide sensitivity. We examined ten sep mutants for resistance/sensitivity to other drugs or stress agents with different and/or the same mechanism of action, Sis of these mutants exhibited other altered resistance/sensitivity phenotypes which were linked to the cycloheximide sensitivity, These six mutants were analyzed by pairwise crosses and found to represent six linkage groups, named scyA-F. One of the mutants showed fragmentation of its vacuolar system and, in addition, its growth was osmotic, low-pi-II and oxidative-stress sensitive.

Policies and practices for the use of information and communications technologies (ICTs) in education in Latin America and the Caribbean

Includes bibliography

N-4-Phenyl-substituted 2-acetylpyridine thiosemicarbazones: Cytotoxicity against human tumor cells, structure-activity relationship studies and investigation on the mechanism of action

N-4-Phenyl 2-acetylpyridine thiosemicarbazone (H2Ac4Ph; N-(phenyl)-2-(1-(pyridin-2-yl)ethylidene) hydrazinecarbothioamide) and its N-4-ortho-, -meta- and -para-fluorophenyl (H2Ac4oFPh, H2Ac4mFPh, H2Ac4pFPh), N-4-ortho-, -meta- and -para-chlorophenyl (H2Ac4oClPh, H2Ac4mClPh, H2Ac4pClPh), N-4-ortho-, -meta- and -para-iodophenyl (H2Ac4oIPh, H2Ac4mIPh, H2Ac4pIPh) and N-4-ortho-, -meta- and -para-nitrophenyl (H2Ac4oNO(2)Ph, H2Ac4mNO(2)Ph, H2Ac4pNO(2)Ph) derivatives were assayed for their cytotoxicity against human malignant breast (MCF-7) and glioma (T98G and U87) cells. The compounds were highly cytotoxic against the three cell lineages (IC50: MCF-7, 52-0.16 nM; T98G, 140-1.0 nM; U87, 160-1.4 nM). All tested thiosemicarbazones were more cytotoxic than etoposide and did not present any haemolytic activity at up to 10(-5) M. The compounds were able to induce programmed cell death. H2Ac4pClPh partially inhibited tubulin assembly at high concentrations and induced cellular microtubule disorganization. (C) 2012 Elsevier Ltd. All rights reserved.

Stress and burnout in postgraduate dental education

High levels of stress and burnout have been documented among dental students and practicing dentists, but evidence among dental residents and postgraduate students is lacking.

Aleatory Sovereignty and the Rule of Sensitive Spaces

Addressing life in borders and refugee camps requires understanding the way these spaces are ruled, the kinds of problems rule poses for the people who live there, and the abilities of inhabitants to remake their own lives. Recent literature on such spaces has been influenced by Agamben's notion of sovereignty, which reduces these spaces and their residents to abstractions. We propose an alternate framework focused on what we call aleatory sovereignty, or rule by chance. This allows us to see camps and borders not only as the outcomes of humanitarian projects but also of anxieties about governance and rule; to see their inhabitants not only as abject recipients of aid, but also as individuals who make decisions and choices in complex conditions; and to show that while the outcome of projects within such spaces is often unpredictable, the assumptions that undergird such projects create regular cycles of implementation and failure.