Role of Candida albicans Tem1 in mitotic exit and cytokinesis

Journal ArticleResearch Support, Non-U.S. Gov'tCopyright © 2014 Elsevier Inc. All rights reserved.Candida albicans demonstrates three main growth morphologies: yeast, pseudohyphal and true hyphal forms. Cell separation is distinct in these morphological forms and the process of separation is closely linked to the completion of mitosis and cytokinesis. In Saccharomyces cerevisiae the small GTPase Tem1 is known to initiate the mitotic exit network, a signalling pathway involved in signalling the end of mitosis and initiating cytokinesis and cell separation. Here we have characterised the role of Tem1 in C. albicans, and demonstrate that it is essential for mitotic exit and cytokinesis, and that this essential function is signalled through the kinase Cdc15. Cells depleted of Tem1 displayed highly polarised growth but ultimately failed to both complete cytokinesis and re-enter the cell cycle following nuclear division. Consistent with its role in activating the mitotic exit network Tem1 localises to spindle pole bodies in a cell cycle-dependent manner. Ultimately, the mitotic exit network in C. albicans appears to co-ordinate the sequential processes of mitotic exit, cytokinesis and cell separation.BBSR

The developmental course of illicit substance use from age 12 to 22: links with depressive, anxiety, and behavior disorders at age 18

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/72027/1/j.1469-7610.2008.01915.x.pd

Gene expression studies for the analysis of domoic acid production in the marine diatom Pseudo-nitzschia multiseries

Background: Pseudo-nitzschia multiseries Hasle (Hasle) (Ps-n) is distinctive among the ecologically important marine diatoms because it produces the neurotoxin domoic acid. Although the biology of Ps-n has been investigated intensely, the characterization of the genes and biochemical pathways leading to domoic acid biosynthesis has been limited. To identify transcripts whose levels correlate with domoic acid production, we analyzed Ps-n under conditions of high and low domoic acid production by cDNA microarray technology and reverse-transcription quantitative PCR (RT-qPCR) methods. Our goals included identifying and validating robust reference genes for Ps-n RNA expression analysis under these conditions. Results: Through microarray analysis of exponential- and stationary-phase cultures with low and high domoic acid production, respectively, we identified candidate reference genes whose transcripts did not vary across conditions. We tested eleven potential reference genes for stability using RT-qPCR and GeNorm analyses. Our results indicated that transcripts encoding JmjC, dynein, and histone H3 proteins were the most suitable for normalization of expression data under conditions of silicon-limitation, in late-exponential through stationary phase. The microarray studies identified a number of genes that were up- and down-regulated under toxin-producing conditions. RT-qPCR analysis, using the validated controls, confirmed the up-regulation of transcripts predicted to encode a cycloisomerase, an SLC6 transporter, phosphoenolpyruvate carboxykinase, glutamate dehydrogenase, a small heat shock protein, and an aldo-keto reductase, as well as the down-regulation of a transcript encoding a fucoxanthin-chlorophyll a-c binding protein, under these conditions. Conclusion: Our results provide a strong basis for further studies of RNA expression levels in Ps-n, which will contribute to our understanding of genes involved in the production and release of domoic acid, an important neurotoxin that affects human health as well as ecosystem function.Plymouth State University Graduate Programs OfficeWoods Hole Oceanographic Institution Academic Programs OfficeNew Hampshire IDeA Network of Biological Research Excellence (NH-INBRE)National Center for Research Resources (U.S.) (Grant 5P20RR030360-03)National Institute of General Medical Sciences (U.S.) (Grant 8P20GM103506-03

Genetic structure of Pseudo-nitzschia pungens (Bacillariophyceae) populations: Implications of a global diversification of the diatom

Pseudo-nitzschia pungens is a planktonic marine diatom known to be widespread in tropical and temperate coastal waters. We examined the population genetic structure of tropical Southeast Asian populations of P. pungens and compared it with those of northern and southern temperate populations. The secondary structures of the nuclear encoded internal transcribed spacer (ITS) region of 164 strains of P. pungens were modeled and analyzed. The tree revealed three ITS entities: clade I (comprised of P. pungens var. pungens) was distributed mainly in northern temperate waters; clade II (comprised of both P. pungens var. pungens and var. cingulata) was mainly from the NE Pacific; and clade III (comprised of both P. pungens var. pungens and var. aveirensis) was restricted to tropical and warm-temperate waters. Hybrids of both P. pungens var. pungens and var. cingulata co-occurred in clades I and II. Sixty haplotypes were revealed from the sequences of 164 strains. Haplotype diversity inferred from the median-joining network was in accordance with phylogenetic analysis, further supporting the grouping of the P. pungens haplogroups. Our results revealed limited gene flow between P. pungens from tropical and temperate waters, and significant population structure, as estimated by an analysis of molecular variance (AMOVA), with 75% of the total ITS variation found among populations (KST = 0.75). This study suggests that distinct environmental clines, such as ocean thermohaline circulation, have a potential for fragmenting and dispersing global populations of P. pungens. Formation of the Isthmus of Panama, in particular, is speculated to play a role in this allopatric differentiation in P. pungens populations worldwide

Pseudo-nitzschia kodamae sp. nov. (Bacillariophyceae), a toxigenic species from the Strait of Malacca, Malaysia

A recent field survey of Pseudo-nitzschia species from coastal waters of Malaysia demonstrated the presence of a novel morphotype, P. sp. Port Dickson, in the Strait of Malacca. In this study, we revisited the site and established five clonal cultures of this morphotype, assessed the strains’ morphology and genetics, and delineated it as a novel species. As observed by electron microscopy, these strains showed morphological features identical to those of the previous field specimens designated as P. sp. Port Dickson. The cells differ from other Pseudo-nitzschia species in the P. pseudodelicatissima complex sensu lato by their lower densities of fibulae, striae and band striae in 10 mm. Molecular data of the nuclear encoded large subunit ribosomal rRNA gene and the internal transcript spacer region (ITS) further supported the delineation of this novel lineage. Based on both morphological and molecular data, P. sp. Port Dickson is considered to represent a new species, for which we propose the name Pseudo-nitzschia kodamae sp. nov. Production of domoic acid (DA) in the strains was examined by FMOC–LC–FLD. Only strains of P. kodamae were observed with a peak corresponding to DA, giving a concentration of 1.2– 42.5 pg DA cell�1. Screening of Pseudo-nitzschia caciantha, Pseudo-nitzschia batesiana, Pseudo-nitzschia fukuyoi and Pseudo-nitzschia lundholmiae cultures from the same waters, however, showed no detectable DA. This is the first report of a potentially toxigenic Pseudo-nitzschia species from the region

Towards an Improved High Resolution Global Long-Term Solar Resource Database

This paper presents an overview of an ongoing project to develop and deliver a solar mapping processing system to the National Renewable Energy Laboratory (NREL) using the data sets that are planned for production at the National Climatic Data Center (NCDC). NCDC will be producing a long-term radiance and cloud property data set covering the globe every three hours at an approximate resolution of 10 x 10 km. NASA, the originators of the Surface meteorology and Solar Energy web portal are collaborating with SUNY-Albany to develop the production system and solar algorithms. The initial result will be a global long-term solar resource data set spanning over 25 years. The ultimate goal of the project is to also deliver this data set and production system to NREL for continual production. The project will also assess the impact of providing these new data to several NREL solar decision support tools

Towards building equitable health systems in Sub-Saharan Africa: lessons from case studies on operational research

<p>Abstract</p> <p>Background</p> <p>Published practical examples of how to bridge gaps between research, policy and practice in health systems research in Sub Saharan Africa are scarce. The aim of our study was to use a case study approach to analyse how and why different operational health research projects in Africa have contributed to health systems strengthening and promoted equity in health service provision.</p> <p>Methods</p> <p>Using case studies we have collated and analysed practical examples of operational research projects on health in Sub-Saharan Africa which demonstrate how the links between research, policy and action can be strengthened to build effective and pro-poor health systems. To ensure rigour, we selected the case studies using pre-defined criteria, mapped their characteristics systematically using a case study development framework, and analysed the research impact process of each case study using the RAPID framework for research-policy links. This process enabled analysis of common themes, successes and weaknesses.</p> <p>Results</p> <p>3 operational research projects met our case study criteria: HIV counselling and testing services in Kenya; provision of TB services in grocery stores in Malawi; and community diagnostics for anaemia, TB and malaria in Nigeria. <b>Political context and external influences: </b>in each case study context there was a need for new knowledge and approaches to meet policy requirements for equitable service delivery. Collaboration between researchers and key policy players began at the inception of operational research cycles. <b>Links</b>: critical in these operational research projects was the development of partnerships for capacity building to support new services or new players in service delivery. <b>Evidence: </b>evidence was used to promote policy dialogue around equity in different ways throughout the research cycle, such as in determining the topic area and in development of indicators.</p> <p>Conclusion</p> <p>Building equitable health systems means considering equity at different stages of the research cycle. Partnerships for capacity building promotes demand, delivery and uptake of research. Links with those who use and benefit from research, such as communities, service providers and policy makers, contribute to the timeliness and relevance of the research agenda and a receptive research-policy-practice interface. Our study highlights the need to advocate for a global research culture that values and funds these multiple levels of engagement.</p