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Chromosome Biorientation Produces Hundreds Of Piconewtons At A Metazoan Kinetochore, Anna A. Ye, Stuart Cane, Thomas J. Maresca

Biology Department Faculty Publication Series

High-fidelity transmission of the genome through cell division requires that all sister kinetochores bind to dynamic microtubules (MTs) from opposite spindle poles. The application of opposing forces to this bioriented configuration produces tension that stabilizes kinetochore–microtubule (kt–MT) attachments. Defining the magnitude of force that is applied to kinetochores is central to understanding the mechano-molecular underpinnings of chromosome segregation; however, existing kinetochore force measurements span orders of magnitude. Here we measure kinetochore forces by engineering two calibrated force sensors into the Drosophila kinetochore protein centromere protein (CENP)-C. Measurements of both reporters indicate that they are, on average, under ∼1–2 piconewtons (pNs) …

Perturbation Analysis Of Calcium, Alkalinity And Secretion During Growth Of Lily Pollen Tubes, Lawrence J. Winship, Caleb Rounds, Peter K. Hepler

Biology Department Faculty Publication Series

Pollen tubes grow by spatially and temporally regulated expansion of new material secreted into the cell wall at the tip of the tube. A complex web of interactions among cellular components, ions and small molecule provides dynamic control of localized expansion and secretion. Cross-correlation studies on oscillating lily (Lilium formosanum Wallace) pollen tubes showed that an increase in intracellular calcium follows an increase in growth, whereas the increase in the alkaline band and in secretion both anticipate the increase in growth rate. Calcium, as a follower, is unlikely to be a stimulator of growth, whereas the alkaline band, as a …

Parasite Removal, But Not Herbivory, Deters Future Parasite Attachment On Tomato, Muvari Connie Tjiurutue, Evan C. Palmer-Young, Lynn S. Adler

Biology Department Faculty Publication Series

Plants face many antagonistic interactions that occur sequentially. Often, plants employ defense strategies in response to the initial damage that are highly specific and can affect interactions with subsequent antagonists. In addition to herbivores and pathogens, plants face attacks by parasitic plants, but we know little about how prior herbivory compared to prior parasite attachment affects subsequent host interactions. If host plants can respond adaptively to these different damage types, we predict that prior parasitism would have a greater deterrent effect on subsequent parasites than would prior herbivory. To test the effects of prior parasitism and prior herbivory on subsequent …

Floral Scent Mimicry And Vector-Pathogen Associations In A Pseudoflower-Inducing Plant Pathogen System, Scott H. Mcart, Timothy D. Miles, Cesar Rodriguez-Saona, Annemiek Schilder, Lynn S. Adler, Matthew J. Grieshop

Biology Department Faculty Publication Series

Several fungal plant pathogens induce ‘pseudoflowers’ on their hosts to facilitate insect-mediated transmission of gametes and spores. When spores must be transmitted to host flowers to complete the fungal life cycle, we predict that pseudoflowers should evolve traits that mimic flowers and attract the most effective vectors in the flower-visiting community. We quantified insect visitation to flowers, healthy leaves and leaves infected with Monilinia vaccinii-corymbosi (Mvc), the causative agent of mummy berry disease of blueberry. We developed a nested PCR assay for detecting Mvc spores on bees, flies and other potential insect vectors. We also collected volatiles from …

Scientific Issues Relevant To Setting Regulatory Criteria To Identify Endocrine-Disrupting Substances In The European Union, Rémy Slama, Jean-Pierre Bourguignon, Barbara Demeneix, Richard Ivell, Giancarlo Panzica, Andreas Kortenkamp, R. Thomas Zoeller

Biology Department Faculty Publication Series

Background: Endocrine disruptors (EDs) are defined by the World Health Organization (WHO) as exogenous compounds or mixtures that alter function(s) of the endocrine system and consequently cause adverse effects in an intact organism, or its progeny, or (sub)populations. European regulations on pesticides, biocides, cosmetics, and industrial chemicals require the European Commission to establish scientific criteria to define EDs.

Objectives: We address the scientific relevance of four options for the identification of EDs proposed by the European Commission.

Discussion: Option 1, which does not define EDs and leads to using interim criteria unrelated to the WHO definition of EDs, is not …

Population Structure In The Model Grass Brachypodium Distachyon Is Highly Correlated With Flowering Differences Across Broad Geographic Areas, Ludmila Tyler, Scott J. Lee, Nelson D. Young, Gregory A. Delulio, Elena Benavente, Michael Reagon, Jessica Sysopha, Riccardo M. Baldini, Angelo Troìa, Samuel P. Hazen, Ana L. Caicedo

Biology Department Faculty Publication Series

The small, annual grass Brachypodium distachyon (L.) Beauv., a close relative of wheat (Triticum aestivum L.) and barley (Hordeum vulgare L.), is a powerful model system for cereals and bioenergy grasses. Genome-wide association studies (GWAS) of natural variation can elucidate the genetic basis of complex traits but have been so far limited in B. distachyon by the lack of large numbers of well-characterized and sufficiently diverse accessions. Here, we report on genotyping-by-sequencing (GBS) of 84 B. distachyon, seven B. hybridum, and three B. stacei accessions with diverse geographic origins including Albania, Armenia, Georgia, Italy, Spain, and …

Florivory Shapes Both Leaf And Floral Interactions, Nicole L. Soper Gorden, Lynn S. Adler

Biology Department Faculty Publication Series

Florivory, or the consumption of flowers, is a ubiquitous interaction that can reduce plant reproduction directly by damaging reproductive tissues and indirectly by deterring pollinators. However, we know surprisingly little about how florivory alters plant traits or the larger community of species interactions. Although leaf damage is known to affect floral traits and interactions in many systems, the consequences of floral damage for leaf traits and interactions are unknown. We manipulated floral damage in Impatiens capensisand measured effects on floral attractive traits and secondary chemicals, leaf secondary chemicals, floral interactions, leaf herbivory, and plant reproduction. We also examined relationships …