Food Prices and Consumer Demand: Differences across Income Levels and Ethnic Groups

Background

Targeted food pricing policies may improve population diets. To assess their effects on inequalities, it is important to determine responsiveness to price changes across income levels and ethnic groups.

Objective

Our goal was to estimate price elasticity (PE) values for major commonly consumed food groups in New Zealand, by income and ethnicity. PE values represent percentage change in demand associated with 1% change in price of that good (own-PE) or another good (cross-PE).

Design

We used food expenditure data from national household economic surveys in 2007/08 and 2009/10 and Food Price Index data from 2007 and 2010. Adopting an Almost Ideal Demand System approach, own-PE and cross-PE estimates were derived for 24 food categories, household income quintiles, and two ethnic groups (Māori and non-Māori).

Results

Own-PE estimates (with two exceptions) ranged from −0.44 to −1.78. Cross-PE estimates were generally small; only 31% of absolute values were greater than 0.10. Excluding the outlier ‘energy drinks’, nine of 23 food groups had significantly stronger own-PEs for the lowest versus highest income quintiles (average regression-based difference across food groups −0.30 (95% CI −0.62 to 0.02)). Six own-PEs were significantly stronger among Māori; the average difference for Māori: non-Māori across food groups was −0.26 (95% CI −0.52 to 0.00).

Conclusions

Food pricing policies have potential to improve population diets. The greater sensitivity of low-income households and Māori to price changes suggests the beneficial effects of such policies on health would be greatest for these groups.     

Catalysis of Protein Folding by Chaperones Accelerates Evolutionary Dynamics in Adapting Cell Populations

Although molecular chaperones are essential components of protein homeostatic machinery, their mechanism of action and impact on adaptation and evolutionary dynamics remain controversial. Here we developed a physics-based ab initio multi-scale model of a living cell for population dynamics simulations to elucidate the effect of chaperones on adaptive evolution. The 6-loci genomes of model cells encode model proteins, whose folding and interactions in cellular milieu can be evaluated exactly from their genome sequences. A genotype-phenotype relationship that is based on a simple yet non-trivially postulated protein-protein interaction (PPI) network determines the cell division rate. Model proteins can exist in native and molten globule states and participate in functional and all possible promiscuous non-functional PPIs. We find that an active chaperone mechanism, whereby chaperones directly catalyze protein folding, has a significant impact on the cellular fitness and the rate of evolutionary dynamics, while passive chaperones, which just maintain misfolded proteins in soluble complexes have a negligible effect on the fitness. We find that by partially releasing the constraint on protein stability, active chaperones promote a deeper exploration of sequence space to strengthen functional PPIs, and diminish the non-functional PPIs. A key experimentally testable prediction emerging from our analysis is that down-regulation of chaperones that catalyze protein folding significantly slows down the adaptation dynamics.     

The Use of Albino Adult Hair and Blond Prepubertal Hair Yields Equivalent Results in an In Vitro Hair Perforation Test to Differentiate Between Different Dermatophytic Fungi

An in vitro hair perforation test is used to differentiate isolates of Trichophyton mentagrophytes and Trichophyton rubrum complexes because morphological criteria are insufficient. Here, we performed in vitro hair perforation tests using blond prepubertal hair and albino adult hair to determine whether they differentiate between fungal species. We tested 43 well-characterized dermatophyte strains, Arthroderma spp. [n = 4], Epidermophyton floccosum [n = 1], Microsporum spp. [n = 8], and Trichophyton spp. [n = 30], and examined hair perforation at 3–30 days postinoculation (p.i.). The perforation times were not significantly different between the two hair types (P > 0.05). The T. mentagrophytes complex strains perforated hair 4–5 days p.i., whereas T. rubrum complex strains perforated hair 13–30 days p.i., except for Trichophyton violaceum, which perforated hair after 6–7 days. Thus, the hair perforation test is highly sensitive (100 %) and specific (100 %) for differentiating T. mentagrophytes from T. rubrum complexes 5 days p.i. At 14 and 30 days, the sensitivity and negative predictive value of the test remained unchanged (100 %), but the specificity was reduced (64.3 and 14.3 %, respectively). Consistent with previous reports, we observed “perforating organs” of zoophilic Microsporum canis and geophilic Microsporum gypseum at 4 and 3 days, respectively. This paper offers a “low-cost” and “low-tech” alternative to differentiating dermatophyte species where standard morphological techniques fail and/or where molecular techniques are not a viable option.     

Karyotype analysis of some Minuartia L. (Caryophyllaceae) taxa

Karyotypic characters, mitotic metaphase chromosomes, monoploid idiograms and karyograms of Minuartia anatolica (Boiss.) Woronow var. phrygia (Bornm.) McNeill, Minuartia anatolica (Boiss.) Woronow var. scleranthoides (Boiss. & Noe) McNeill, Minuartia corymbulosa (Boiss. & Balansa) McNeill var. gypsophilloides McNeill and Minuartia aksoyi M.Koç & Hamzao?lu were investigated for the first time. Analysis of somatic metaphases showed that the chromosome numbers and the formulas of these taxa were 2n = 24 = 14m + 6sm + 4st for Minuartia anatolica var. phrygia, 2n = 14 = 6m + 8sm for Minuartia anatolica var. scleranthoides, 2n = 14 = 6m + 4sm + 4st for Minuartia corymbulosa var. gypsophilloides and 2n = 30 = 14m + 10sm + 6st for Minuartia aksoyi. No satellites were observed in the karyotypes of these taxa. Karyotype asymmetry was estimated by many different methods, namely the Stebbins classification, the karyotype asymmetry index (As K %), the total form percent (TF %), the Rec and Syi indices, the intrachromosomal asymmetry index (A1) and interchromosomal asymmetry index (A2), the dispersion index (DI), the degree of asymmetry of karyotype (A index) and the asymmetry index (AI).     

Galatella anatolica sp. nov. (Asteraceae: Astereae) from Osmaniye,Turkey

Galatella anatolica Hamzao?lu & Budak sp. nov. (Asteraceae), collected from Osmaniye (Turkey) is here described as a new species. It is similar to G. angustissima (Tausch) Novopokr. in general habit. Both have stems with few branches and 1‐veined middle leaves, but are distinguished by involucral features, series of phyllaries, and lengths of disc florets, achenes and pappus.     

Variables of Microbial Response in Natural Soil Aggregates for Soil Characterization in Different Fluvial Land Shapes

The main objective of this study was to determine changes in microbial response in natural soil aggregates for soil characterization in different fluvial land shapes. This study was carried out in fluvial lands formed on accumulated sediment depositions carried by K?z?l?rmak River. The majority soils of the study area were classified as Typic Ustifluvent and Typic Haplustept in Soil Taxonomy. It was found that macroaggregates (especially >6300 μm and 2000–4750 μm diameters) of all soil samples were higher than microaggregate of soils. In addition, it was determined that the C_org content varies between 0.41–0.91% in soil samples. C_mic content was also found higher level in aggregates involved <250 and 250–425 μm diameters as compared to other aggregate size classes. Moreover, we detected that C_org:C_mic ratio was much higher in macroaggregates than in microaggregate fractions. BR levels were also greater in macroaggregates of >6,300, 4,750–6,300 and 2,000–4,750 μm than in the other macroaggregates sizes and microaggregates. Consequently, macroaggregates have relatively more C_org level than the C_org level in microaggregates, even if the absolute values of C_mic were the lower. This study thus evidenced contrasting microbial habitats and their response in different soil aggregate size formed in various developed soils.     

Historical Biogeography and Diversification of Truffles in the Tuberaceae and Their Newly Identified Southern Hemisphere Sister Lineage

Truffles have evolved from epigeous (aboveground) ancestors in nearly every major lineage of fleshy fungi. Because accelerated rates of morphological evolution accompany the transition to the truffle form, closely related epigeous ancestors remain unknown for most truffle lineages. This is the case for the quintessential truffle genus Tuber, which includes species with socio-economic importance and esteemed culinary attributes. Ecologically, Tuber spp. form obligate mycorrhizal symbioses with diverse species of plant hosts including pines, oaks, poplars, orchids, and commercially important trees such as hazelnut and pecan. Unfortunately, limited geographic sampling and inconclusive phylogenetic relationships have obscured our understanding of their origin, biogeography, and diversification. To address this problem, we present a global sampling of Tuberaceae based on DNA sequence data from four loci for phylogenetic inference and molecular dating. Our well-resolved Tuberaceae phylogeny shows high levels of regional and continental endemism. We also identify a previously unknown epigeous member of the Tuberaceae – the South American cup-fungus Nothojafnea thaxteri (E.K. Cash) Gamundí. Phylogenetic resolution was further improved through the inclusion of a previously unrecognized Southern hemisphere sister group of the Tuberaceae. This morphologically diverse assemblage of species includes truffle (e.g. Gymnohydnotrya spp.) and non-truffle forms that are endemic to Australia and South America. Southern hemisphere taxa appear to have diverged more recently than the Northern hemisphere lineages. Our analysis of the Tuberaceae suggests that Tuber evolved from an epigeous ancestor. Molecular dating estimates Tuberaceae divergence in the late Jurassic (∼156 million years ago), with subsequent radiations in the Cretaceous and Paleogene. Intra-continental diversification, limited long-distance dispersal, and ecological adaptations help to explain patterns of truffle evolution and biodiversity.