Inflorescence commitment and subsequent development differ in their responses to temperature and photoperiod in Osteospermum jucundum

Although Osteospermum is a species which is known to require a period of chilling to induce flowering, the precise form of the relationships between temperature and photoperiod on the phases of flowering has not been quantified. This study aimed to investigate the effects of temperature and photoperiod on time to inflorescence commitment and on the rate of subsequent floral development in Osteospermum jucundum cv. Zulu. To assess how temperature and photoperiod affected the number of days needed for inflorescence commitment, plants were transferred from a range of photothermal environments to a non‐inductive environment. The effect of temperature and photoperiod on subsequent inflorescence development was examined by transferring plants with initiated inflorescences to a range of photothermal environments. Inflorescence commitment occurred first in plants grown at a low average diurnal temperature (10.6°C), but no evidence was found to suggest that photoperiod affected the duration of this phase. Once initiated, high temperatures and long days hastened inflorescence development. The rate of progress to flowering from initiation increased linearly with photoperiod and temperature (up to an optimum of 23.5°C).     

A systematic comparison of protein structure classifications: SCOP, CATH and FSSP.

BACKGROUND: Several methods of structural classification have been developed to introduce some order to the large amount of data present in the Protein Data Bank. Such methods facilitate structural comparisons and provide a greater understanding of structure and function. The most widely used and comprehensive databases are SCOP, CATH and FSSP, which represent three unique methods of classifying protein structures: purely manual, a combination of manual and automated, and purely automated, respectively. In order to develop reliable template libraries and benchmarks for protein-fold recognition, a systematic comparison of these databases has been carried out to determine their overall agreement in classifying protein structures. RESULTS: Approximately two-thirds of the protein chains in each database are common to all three databases. Despite employing different methods, and basing their systems on different rules of protein structure and taxonomy, SCOP, CATH and FSSP agree on the majority of their classifications. Discrepancies and inconsistencies are accounted for by a small number of explanations. Other interesting features have been identified, and various differences between manual and automatic classification methods are presented. CONCLUSIONS: Using these databases requires an understanding of the rules upon which they are based; each method offers certain advantages depending on the biological requirements and knowledge of the user. The degree of discrepancy between the systems also has an impact on reliability of prediction methods that employ these schemes as benchmarks. To generate accurate fold templates for threading, we extract information from a consensus database, encompassing agreements between SCOP, CATH and FSSP.     

Stability and Change in In-Group Mate Preferences among Young People in Ethiopia Are Predicted by Food Security and Gender Attitudes,but Not by Expected Pathogen Exposures

There is broad anthropological interest in understanding how people define “insiders” and “outsiders” and how this shapes their attitudes and behaviors toward others. As such, a suite of hypotheses has been proposed to account for the varying degrees of in-group preference between individuals and societies. We test three hypotheses related to material insecurity, pathogen stress, and views of gender equality among cross-sectional (n = 1896) and longitudinal (n = 1002) samples of young people in Ethiopia (aged 13–17 years at baseline) to explore stability and change in their preferences for coethnic spouses. We show that food insecurity is associated with a greater likelihood of intolerant mate preferences. We also find that young people who hold more gender equitable attitudes tended to hold more tolerant mate preferences. Finally, we find no support for the hypothesis that expected pathogen exposure is associated with intolerant mate preferences. Our results most strongly support a material insecurity hypothesis of in-group bias, which assumes that uncertainty over meeting basic needs leads people to favor those in their in-group. As such, our findings join a small but growing group of studies that highlight the importance of material insecurity for understanding tolerance, xenophobia, in-group bias, and favoritism.     

The shape of things to come? household dependency ratio and adolescent nutritional status in rural and urban Ethiopia

Several related demographic trends are occurring in developing countries: youth comprise a large portion of populations, fertility rates are declining, and urban dwellers are increasing. As fertility rates decline and populations age, the decline in the ratio of young dependents to working age adults is expected to free up household resources, which can be invested in human capital, including youth nutritional wellbeing. We test this hypothesis in a sample of youth (n = 1,934) in Southwestern Ethiopia. Multiple measures of achieved growth and nutritional status are explored (weight, height, mid-upper arm circumference (MUAC), body mass index (BMI) and body mass index for age z-score (BMIZ), weight for age z-score (WAZ), and height for age z-score (HAZ)). In multivariable models controlling for the effects of income, age, gender, and youth workloads, youth living in rural settings had significantly lower weight (1.24 kg lighter), MUAC (0.67 cm lower), BMI (0.45 BMI lower), BMIZ (0.27 lower), HAZ (0.14 HAZ lower), and WAZ (0.3 WAZ lower) than urban youth (all P < 0.01). Compared with youth in the lowest dependency ratio households, results show that youth in households with the highest dependency ratios were estimated to be 1.3 kg lighter, have 0.67 cm smaller MUAC, and BMI that was 0.59 lower (all P<0.01). Similar results were found for WAZ (0.21 lower) and BMIZ (0.36 lower). Youth height and HAZ were not associated with household dependency. These results may point toward increasing levels of human capital investments in Ethiopian youth as fertility levels decline and populations urbanize.     

The design of 8,8-dimethyl[1,6]naphthyridines as potential anticonvulsant agents

Starting from a series of 7-linked tetrahydroisoquinoline derivatives, as exemplified by SB-270664, a new series of 8,8-dimethylnaphthyridine compounds has been identified. SAR studies around these attractive leads have provided compounds such as 12 which display excellent anticonvulsant activity and an encouraging pharmacokinetic profile in vivo.     

A novel docking domain interface model predicting recombination between homoeologous modular biosynthetic gene clusters

An in silico model for homoeologous recombination between gene clusters encoding modular polyketide synthases (PKS) or non-ribosomal peptide synthetases (NRPS) was developed. This model was used to analyze recombination between 12 PKS clusters from Streptomyces species and related genera to predict if new clusters might give rise to new products. In many cases, there were only a limited number of recombination sites (about 13 per cluster pair), suggesting that recombination may pose constraints on the evolution of PKS clusters. Most recombination events occurred between pairs of ketosynthase (KS) domains, allowing the biosynthetic outcome of the recombinant modules to be predicted. About 30% of recombinants were predicted to produce polyketides. Four NRPS clusters from Streptomyces strains were also used for in silico recombination. They yielded a comparable number of recombinants to PKS clusters, but the adenylation (A) domains contained the largest proportion of recombination events; this might be a mechanism for producing new substrate specificities. The extreme G + C-content, the presence of linear chromosomes and plasmids, as well as the lack of a mutSL-mismatch repair system should favor production of recombinants in Streptomyces species.