Showing 21 - 30 of 257 Items
Replacement of histidines of light harvesting chlorophyll a/b binding protein II disrupts chlorophyll-Protein complex assembly
Date: 1990-01-01
Creator: Bruce D. Kohorn
Access: Open access
- Eukaryotic light harvesting proteins (LHCPs) bind pigments and assemble into complexes (LHCs) that channel light energy into photosynthetic reaction centers. The structures of several prokaryotic LHCPs are known and histidines are important for the binding of the associated pigments. It has been difficult to predict how the eukaryotic LHCPs associate with pigments as the structure of the major LHCP of photosystem II is not yet known. While each LHCPII binds approximately 13 chlorophylls the protein contains only three histidines, one in each putative transmembrane helix. Experiments that use isolated pea (Pisum sativum L.) chloroplasts and mutant LHCPII synthesized in vitro show that the substitution of either an alanine or an arginine for each histidine residue inhibits some aspect of LHCII assembly. The histidine of the first membrane helix, but not the second or third, may be involved in the transport across the chloroplast envelope. No histidine alone is essential for the insertion of LHCP into thylakoid membranes, yet arginine substitutions are more inhibitory than those of alanine. The histidine replacements have their most pronounced effect on the assembly of LHCP into LHCII.
Simplified insertion of transgenes onto balancer chromosomes via recombinase-mediated cassette exchange
Date: 2012-05-01
Creator: Florence F. Sun, Justine E. Johnson, Martin P. Zeidler, Jack R. Bateman
Access: Open access
- Balancer chromosomes are critical tools for Drosophila genetics. Many useful transgenes are inserted onto balancers using a random and inefficient process. Here we describe balancer chromosomes that can be directly targeted with transgenes of interest via recombinase-mediated cassette exchange (RMCE). ©2012 Sun et al.
Investigating enhancer regulation through chromatin conformation in Drosophila Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2020-01-01
Creator: Hannah D. Konkel
Access: Access restricted to the Bowdoin Community
Maximal stomatal conductance to water and plasticity in stomatal traits differ between native and invasive introduced lineages of Phragmites australis in North America
Date: 2016-01-27
Creator: V. Douhovnikoff, S. H. Taylor, E. L.G. Hazelton, C. M. Smith, J., O'Brien
Access: Open access
- The fitness costs of reproduction by clonal growth can include a limited ability to adapt to environmental and temporal heterogeneity. Paradoxically, some facultatively clonal species are not only able to survive, but colonize, thrive and expand in heterogeneous environments. This is likely due to the capacity for acclimation (sensu stricto) that compensates for the fitness costs and complements the ecological advantages of clonality. Introduced Phragmites australis demonstrates great phenotypic plasticity in response to temperature, nutrient availability, geographic gradient, water depths, habitat fertility, atmospheric CO2, interspecific competition and intraspecific competition for light. However, no in situ comparative subspecies studies have explored the difference in plasticity between the non-invasive native lineage and the highly invasive introduced lineage. Clonality of the native and introduced lineages makes it possible to control for genetic variation, making P. australis a unique system for the comparative study of plasticity. Using previously identified clonal genotypes, we investigated differences in their phenotypic plasticity through measurements of the lengths and densities of stomata on both the abaxial (lower) and adaxial (upper) surfaces of leaves, and synthesized these measurements to estimate impacts on maximum stomatal conductance to water (gwmax). Results demonstrated that at three marsh sites, invasive lineages have consistently greater gwmax than their native congeners, as a result of greater stomatal densities and smaller stomata. Our analysis also suggests that phenotypic plasticity, determined as within-genotype variation in gwmax, of the invasive lineage is similar to, or exceeds, that shown by the native lineage.
Can AFLP genome scans detect small islands of differentiation? The case of shell sculpture variation in the periwinkle Echinolittorina hawaiiensis
Date: 2011-08-01
Creator: Kimberly A. Tice, D. B. Carlon
Access: Open access
- Genome scans have identified candidate regions of the genome undergoing selection in a wide variety of organisms, yet have rarely been applied to broadly dispersing marine organisms experiencing divergent selection pressures, where high recombination rates can reduce the extent of linkage disequilibrium (LD) and the ability to detect genomic regions under selection. The broadly dispersing periwinkle Echinolittorina hawaiiensis exhibits a heritable shell sculpture polymorphism that is correlated with environmental variation. To elucidate the genetic basis of phenotypic variation, a genome scan using over 1000 AFLP loci was conducted on smooth and sculptured snails from divergent habitats at four replicate sites. Approximately 5% of loci were identified as outliers with Dfdist, whereas no outliers were identified by BayeScan. Closer examination of the Dfdist outliers supported the conclusion that these loci were false positives. These results highlight the importance of controlling for Type I error using multiple outlier detection approaches, multitest corrections and replicate population comparisons. Assuming shell phenotypes have a genetic basis, our failure to detect outliers suggests that the life history of the target species needs to be considered when designing a genome scan. © 2011 The Authors. Journal of Evolutionary Biology © 2011 European Society For Evolutionary Biology.
An analysis and characterization of Sonic Hedgehog and Fgf genes in Danio rerio embryonic tooth development This record is embargoed.
- Embargo End Date: 2027-05-18
Date: 2022-01-01
Creator: Lauren Kanoelani Waters
Access: Embargoed
The influence of Toll 7 on the neuroplasticity of auditory neurons in the Mediterranean field cricket (Gryllus bimaculatus) This record is embargoed.
- Embargo End Date: 2028-05-16
Date: 2023-01-01
Creator: Brooke Asherman
Access: Embargoed
A phylogenomic approach to the blue-barred parrotfish (Scarus ghobban) complex across the Indian and Pacific Oceans This record is embargoed.
- Embargo End Date: 2025-05-17
Date: 2024-01-01
Creator: Eban Charles
Access: Embargoed
The Role of Pectin Methyl Esterase in Pectin Activation of WAK Regulated Stress Response in Arabidopsis thaliana Access to this record is restricted to members of the Bowdoin community. Log in here to view.
Date: 2014-05-01
Creator: Nicholas J Saba
Access: Access restricted to the Bowdoin Community
Captured segment exchange: A strategy for custom engineering large genomic regions in Drosophila melanogaster
Date: 2013-04-24
Creator: Jack R. Bateman, Michael F. Palopoli, Sarah T. Dale, Jennifer E. Stauffer, Anita L., Shah, Justine E. Johnson, Conor W. Walsh, Hanna Flaten, Christine M. Parsons
Access: Open access
- Site-specific recombinases (SSRs) are valuable tools for manipulating genomes. In Drosophila, thousands of transgenic insertions carrying SSR recognition sites have been distributed throughout the genome by several large-scale projects. Here we describe a method with the potential to use these insertions to make custom alterations to the Drosophila genome in vivo. Specifically, by employing recombineering techniques and a dual recombinase-mediated cassette exchange strategy based on the phiC31 integrase and FLP recombinase, we show that a large genomic segment that lies between two SSR recognition-site insertions can be "captured" as a target cassette and exchanged for a sequence that was engineered in bacterial cells. We demonstrate this approach by targeting a 50-kb segment spanning the tsh gene, replacing the existing segment with corresponding recombineered sequences through simple and efficient manipulations. Given the high density of SSR recognition-site insertions in Drosophila, our method affords a straightforward and highly efficient approach to explore gene function in situ for a substantial portion of the Drosophila genome. © 2013 by the Genetics Society of America.