The metabolic rate of cultured muscle cells from hybrid Coturnix quail is intermediate to that of muscle cells from fast-growing and slow-growing Coturnix quail

Clara Cooper-Mullin, Ana Gabriela Jimenez, Nicholas B. Anthony, Matthew Wortman, Joseph B. Williams. 2015. Journal of Comparative Physiology. 185(5): 547-557.

Abstract

Growth rate is a fundamental parameter of an organism’s life history and varies 30-fold across bird species. To explore how whole-organism growth rate and the metabolic rate of cultured muscle cells are connected, two lines of Japanese quail (Coturnix coturnix japonica), one that had been artificially selected for fast growth for over 60 generations and a control line were used to culture myoblasts. In line with previous work, myoblasts from the fast growth line had significantly higher rates of oxygen consumption, glycolytic flux, and higher mitochondrial volume than myoblasts from the control line, indicating that an increase in growth rate is associated with a concomitant increase in cellular metabolic rates and that mitochondrial density contributes to the differences in rates of metabolism between the lines. We reared chicks from two hybrid lines with reciprocal parental configurations for growth rate to explore the effect of maternally inherited mitochondrial DNA on rates of growth and metabolism. Growth rates of chicks, cellular basal oxygen consumption, glycolytic flux, and mitochondrial volume in myoblasts from chicks from both reciprocal crosses were intermediate to the fast and control lines. This indicates that genes in the nucleus have a strong influence on metabolic rates at the cellular level, compared with maternally inherited mitochondrial DNA.

Williams Lab


Diversification of North American natricine snakes

John D. McVay, Oscar Flores-Villela and Bryan Carstens. 2015. Biological Journal of the Linnean Society. DOI: 10.1111/bij.12558

Abstract

The phylogeny of thamnophiine snakes has not been fully resolved, largely because previous phylogenetic estimates have been based on incomplete taxon sampling or relied solely on mitochondrial sequence data. To address this deficiency, we collected data from multiple autosomal loci collected from 50 taxa before estimating the most robust phylogeny of Thamnophiini to date. Our findings clarify the relationships of taxa not previously included in molecular analyses and also lend evidence to previously recommended taxonomic revisions. Differences in topological estimates between competing models of evolution were minimal and not strongly supported; however, a multispecies coalescent model of evolution was highly favoured over a concatenated model based on marginal likelihood estimates. Additionally, we estimated the timing of divergence among the three major lineages to have occurred during the Miocene period (approximately 11–14 Mya), followed by a decline in speciation rates in all major lineages.

Carstens Lab


Essential amino acid provisioning by termite-associated gut microbiota

Ayayee PA, Jones SC, Sabree ZL. (2015) Essential amino acid provisioning by termite-associated gut microbiota. PeerJ PrePrints 3:e1357

Abstract

Gut-associated microbes of many insects provide a variety of beneficial nutritive functions to their hosts such as the provisioning of essential amino acids (EAAs) to those that feed on diets limited in assimilable nitrogen (i.e., wood). We investigated this function by the gut microbiota of the eastern subterranean termite (Reticulitermes flavipes) using 13C-stable isotope analysis of EAAs in the diet and termite samples. Evidence of possible microbe input was revealed by 13C-depletion of termite carcass (-27.0 ± 0.43‰, mean ± s.e.), and termite gut filtrate samples (-27.3 ± 0.58‰) relative to their wood diet (-26.0 ± 0.48‰) (F (2, 63) = 6.2, P < 0.004). An investigation of the identity of non-dietary EAA sources determined that termites predominantly incorporated EAAs derived from bacteria, with minor fungal input. The most likely means of EAA acquisition is through proctodeal trophallaxis (mouth-anus feeding), a well-established feature of termite colony nestmates, and subsequent digestion of the microbial fraction in the transferred food. Our study provides empirical data in support of the gut microbial EAA provisioning function in termites by using 13C-stable isotopes to determine the microbial origins of incorporated EAAs in termite tissues.

Sabree lab


Phylogenetic relationships in Asarum: Effect of data partitioning and a revised classification

Brandon T. Sinn, Lawrence M. Kelly and John V. Freudenstein. 2015.

Abstract

Generic boundaries and infrageneric relationships among the charismatic temperate magnoliid Asarum sensu lato (Aristolochiaceae) have long been uncertain. Previous molecular phylogenetic analyses used either plastid or nuclear loci alone and varied greatly in their taxonomic implications for the genus. We analyzed additional molecular markers from the nuclear and plastid genomes, reevaluated the possibility of a derived loss of autonomous self-pollination, and investigated the topological effects of matrix-partitioning-scheme choice.

Freudenstein Lab