Life Sciences Commons^™

Cross-Tolerance And Cross-Talk In The Cold: Relating Low Temperatures To Desiccation And Immune Stress In Insects., Brent J Sinclair, Laura V Ferguson, Golnaz Salehipour-Shirazi, Heath A Macmillan

Biology Publications

Multiple stressors, both abiotic and biotic, often are experienced simultaneously by organisms in nature. Responses to these stressors may share signaling pathways ("cross-talk") or protective mechanisms ("cross-tolerance"). Temperate and polar insects that must survive the winter experience low temperatures accompanied by additional abiotic stressors, such as low availability of water. Cold and desiccation have many similar effects at a cellular level, and we present evidence that the cellular mechanisms that protect against cold stress also protect against desiccation, and that the responses to cold and dehydration likely evolved as cross-tolerance. By contrast, there are several lines of evidence suggesting that …

Using Economic Instruments To Develop Effective Management Of Invasive Species: Insights From A Bioeconomic Model, Shana M. Mcdermott, Rebecca E. Irwin, Brad W. Taylor

Dartmouth Scholarship

Economic growth is recognized as an important factor associated with species invasions. Consequently, there is increasing need to develop solutions that combine economics and ecology to inform invasive species management. We developed a model combining economic, ecological, and sociological factors to assess the degree to which economic policies can be used to control invasive plants. Because invasive plants often spread across numerous properties, we explored whether property owners should manage invaders cooperatively as a group by incorporating the negative effects of invader spread in management decisions (collective management) or independently, whereby the negative effects of invasive plant spread are ignored …

Identification Of Cold-Responsive Genes In A New Zealand Alpine Stick Insect Using Rna-Seq., Luke T Dunning, Alice B Dennis, Duckchul Park, Brent J Sinclair, Richard D Newcomb, Thomas R Buckley

Biology Publications

The endemic New Zealand alpine stick insect Micrarchus nov. sp. 2 regularly experiences sub-zero temperatures in the wild. 454-based RNA-Seq was used to generate a de novo transcriptome and differentiate between treatments to investigate the genetic basis of cold tolerance. Non cold-treated individuals were compared to those exposed to 0°C for 1 h followed by a 1 h recovery period at 20°C. We aligned 607,410 Roche 454 reads, generating a transcriptome of 5235 contigs. Differential expression analysis ranked candidate cold responsive genes for qPCR validation by P-value. The top nine up-regulated candidates, together with eight a priori targets identified from …

Mechanisms Of Signal Transduction By Ethylene: Overlapping And Non-Overlapping Signalling Roles In A Receptor Family, Samina N. Shakeel, Xiaomin Wang, Brad M. Binder, G. Eric Schaller

Dartmouth Scholarship

The plant hormone ethylene regulates growth and development as well as responses to biotic and abiotic stresses. Over the last few decades, key elements involved in ethylene signal transduction have been identified through genetic approaches, these elements defining a pathway that extends from initial ethylene perception at the endoplasmic reticulum to changes in transcriptional regulation within the nucleus. Here, we present our current understanding of ethylene signal transduction, focusing on recent developments that support a model with overlapping and non-overlapping roles for members of the ethylene receptor family. We consider the evidence supporting this model for sub-functionalization within the receptor …

Reconstruction Of Family-Level Phylogenetic Relationships Within Demospongiae (Porifera) Using Nuclear Encoded Housekeeping Genes, Malcolm S. Hill, April Hill, Jose Lopez, Kevin J. Peterson

Dartmouth Scholarship

Background: Demosponges are challenging for phylogenetic systematics because of their plastic and relatively simple morphologies and many deep divergences between major clades. To improve understanding of the phylogenetic relationships within Demospongiae, we sequenced and analyzed seven nuclear housekeeping genes involved in a variety of cellular functions from a diverse group of sponges.

Methodology/Principal Findings: We generated data from each of the four sponge classes (i.e., Calcarea, Demospongiae, Hexactinellida, and Homoscleromorpha), but focused on family-level relationships within demosponges. With data for 21 newly sampled families, our Maximum Likelihood and Bayesian-based approaches recovered previously phylogenetically defined taxa: Keratosap, Myxospongiaep, Spongillidap, Haploscleromorphap (the …