Population Structure in Japanese Rice Population.

Population structure in Japanese rice population.

Breed Sci. 2013 Mar; 63(1): 49-57
Yamasaki M, Ideta O

It is essential to elucidate genetic diversity and relationships among even related individuals and populations for plant breeding and genetic analysis. Since Japanese rice breeding has improved agronomic traits such as yield and eating quality, modern Japanese rice cultivars originated from narrow genetic resource and closely related. To resolve the population structure and genetic diversity in Japanese rice population, we used a total of 706 alleles detected by 134 simple sequence repeat markers in a total of 114 cultivars composed of 94 improved varieties and 20 landraces, which are representative and important for Japanese rice breeding. The landraces exhibit greater gene diversity than improved lines, suggesting that landraces can provide additional genetic diversity for future breeding. Model-based Bayesian clustering analysis revealed six subgroups and admixture situation in the cultivars, showing good agreement with pedigree information. This method could be superior to phylogenetic method in classifying a related population. The leading Japanese rice cultivar, Koshihikari is unique due to the specific genome constitution. We defined Japanese rice diverse sets that capture the maximum number of alleles for given sample sizes. These sets are useful for a variety of genetic application in Japanese rice cultivars. HubMed – eating


Whole-body protein turnover reveals the cost of detoxification of secondary metabolites in a vertebrate browser.

J Comp Physiol B. 2013 May 3;
Au J, Marsh KJ, Wallis IR, Foley WJ

The detoxification limitation hypothesis predicts that the metabolism and biotransformation of plant secondary metabolites (PSMs) elicit a cost to herbivores. There have been many attempts to estimate these costs to mammalian herbivores in terms of energy, but this ignores what may be a more important cost-increases in protein turnover and concomitant losses of amino acids. We measured the effect of varying dietary protein concentrations on the ingestion of two PSMs (1,8 cineole-a monoterpene, and benzoic acid-an aromatic carboxylic acid) by common brushtail possums (Trichosurus vulpecula). The dietary protein concentration had a small effect on how much cineole possums ingested. In contrast, protein had a large effect on how much benzoate they ingested, especially at high dietary concentrations of benzoate. This prompted us to measure the effects of dietary protein and benzoate on whole-body protein turnover using the end-product method following an oral dose of [(15)N] glycine. Increasing the concentration of dietary protein in diets without PSMs improved N balance but did not influence whole-body protein turnover. In contrast, feeding benzoate in a low-protein diet pushed animals into negative N balance. The concomitant increases in the rates of whole-body protein turnover in possums eating diets with more benzoate were indicative of a protein cost of detoxification. This was about 30 % of the dietary N intake and highlights the significant effects that PSMs can have on nutrient metabolism and retention. HubMed – eating


Modelling the human response to saltiness.

Food Funct. 2013 May 2;
Le Révérend BJ, Norton IT, Bakalis S

Eating is a complex process with a range of phenomena occurring simultaneously, including fracture, temperature changes, mixing with saliva, flavour and aroma release. Sensory perception as experienced in the oral cavity has a strong effect on the overall acceptability of the food. Thus in an engineering sense one would want to be able to understand and predict phenomena for different food matrices in order to design more palatable foods through understanding food oral processing without the health concerns of adding salt, fat and sugar. In this work we seek to obtain such an understanding for salt release from food matrices and perception viewing the oral processing as a physical/chemical reactor. A set of equations was developed to account for mass balance and transfer. Data required for the model such as effective diffusivity and mixing times were obtained from the chemical engineering literature. The model predictions compared favourably with published TI data, managing to capture key phenomena including response to pulsed salt release. The model was used to predict response to a range of food matrices and indicated that for solids and thickened liquid food products there is the potential to modulate consumer response by pulsing the release of sodium. HubMed – eating