Differences in life‐cycle stage components between native and introduced ranges of five woody Fabaceae species

Understanding differences in the components of life‐cycle stages of species between their native and introduced ranges can provide insights into the process of species transitioning from introduction to naturalization and invasion. We examined reproductive variables of the germination (seed predation, seed viability, time to germination), seed output (crown projection, seed production, seed weight) and dispersal (seed weight, dispersal investment) stages of five woody Fabaceae species, comparing native and introduced ranges. We predicted that each species would differ in reproductive variables of at least one life‐cycle stage between their native and introduced ranges, thus allowing us to determine the life‐cycle stage most associated with invasion success in the introduced range. Acacia melanoxylon and Paraserianthes lophantha had reduced seed predation in their introduced ranges while P. lophantha also had higher seed viability indicating that the germination life‐cycle stage is most strongly associated with their invasion success in the introduced range. Only Acacia longifolia varied between ranges for the seed output stage due to larger plant size, greater seed production and smaller seed size in its introduced range. Similar to A. longifolia, Acacia cyclops had smaller seed size in its introduced range but did not have any other variable differences between ranges suggesting that the dispersal stage is best associated with its invasion success in the introduced range. Surprisingly, Acacia saligna was the only species without a clear life‐cycle stage difference between ranges despite it being one of the more invasive acacia species in Australia. Although we found clear differences in reproductive variables associated with life‐cycle stages between native and introduced ranges of these five species, these differences were largely species‐specific. This suggests that a species invasion strategy into a novel environment is complex and varies among species depending on the environmental context, phenotypic plasticity and genotypic variation in particular traits.     

QTL Mapping of Growth-Related Traits in a Full-Sib Family of Rubber Tree (Hevea brasiliensis) Evaluated in a Sub-Tropical Climate

The rubber tree (Hevea spp.), cultivated in equatorial and tropical countries, is the primary plant used in natural rubber production. Due to genetic and physiological constraints, inbred lines of this species are not available. Therefore, alternative approaches are required for the characterization of this species, such as the genetic mapping of full-sib crosses derived from outbred parents. In the present study, an integrated genetic map was obtained for a full-sib cross family with simple sequence repeats (SSRs) and expressed sequence tag (EST-SSR) markers, which can display different segregation patterns. To study the genetic architecture of the traits related to growth in two different conditions (winter and summer), quantitative trait loci (QTL) mapping was also performed using the integrated map. Traits evaluated were height and girth growth, and the statistical model was based in an extension of composite interval mapping. The obtained molecular genetic map has 284 markers distributed among 23 linkage groups with a total length of 2688.8 cM. A total of 18 QTLs for growth traits during the summer and winter seasons were detected. A comparison between the different seasons was also conducted. For height, QTLs detected during the summer season were different from the ones detected during winter season. This type of difference was also observed for girth. Integrated maps are important for genetics studies in outbred species because they represent more accurately the polymorphisms observed in the genitors. QTL mapping revealed several interesting findings, such as a dominance effect and unique segregation patterns that each QTL could exhibit, which were independent of the flanking markers. The QTLs identified in this study, especially those related to phenotypic variation associated with winter could help studies of marker-assisted selection that are particularly important when the objective of a breeding program is to obtain phenotypes that are adapted to sub-optimal regions.     

The Effects of Demographic Factors on the Environmental Awareness of Omani Citizens

In year 2007, a survey was conducted in the Sultanate of Oman in order to evaluate the current environmental awareness of the Omani general public and their willingness to protect the environment. The focus of the survey was to explore the role played by demographic factors (sex, age, and education level) in determining the environmental awareness of the Omani public. The survey was administered to 425 respondents among all areas of the entire Muscat governorate in Oman. The results of the survey revealed that the environmental awareness of the Omani public was related to gender, age, and education level. Males were found to have a higher level of knowledge about environmental issues than females. Males were also more environmentally concerned and tended to engage in more environmental behaviors than females. Younger and more educated respondents tended to be more knowledgeable and concerned about the environment than older and less educated respondents.     

Quinolinic acid stimulates synaptosomal glutamate release and inhibits glutamate uptake into astrocytes

Quinolinic acid (QA) is an endogenous neurotoxin involved in various neurological diseases, whose action seems to be exerted via glutamatergic receptors. However, the exact mechanism responsible for the neurotoxicity of QA is far from being understood. We have previously reported that QA inhibits vesicular glutamate uptake. In this work, investigating the effects of QA on the glutamatergic system from rat brain, we have demonstrated that QA (from 0.1 to 10mM) had no effect on synaptosomal L-[3H]glutamate uptake. The effect of QA on glutamate release in basal (physiological K+ concentration) or depolarized (40 mM KCl) conditions was evaluated. QA did not alter K+-stimulated glutamate release, but 5 and 10mM QA significantly increased basal glutamate release. The effect of dizolcipine (MK-801), a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptor on glutamate release was investigated. MK-801 (5 microM) did not alter glutamate release per se, but completely abolished the QA-induced glutamate release. NMDA (50 microM) also stimulated glutamate release, without altering QA-induced glutamate release, suggesting that QA effects were exerted via NMDA receptors. QA (5 and 10mM) decreased glutamate uptake into astrocyte cell cultures. Enhanced synaptosomal glutamate release, associated with inhibition of glutamate uptake into astrocytes induced by QA could contribute to increase extracellular glutamate concentrations which ultimately lead to overstimulation of the glutamatergic system. These data provide additional evidence that neurotoxicity of QA may be also related to disturbances on the glutamatergic transport system, which could result in the neurological manifestations observed when this organic acid accumulates in the brain.     

How Do Tracking and Changes in Dietary Pattern during Adolescence Relate to the Amount of Body Fat in Early Adulthood?

Background

Few studies have addressed the influence of dietary patterns (DP) during adolescence on the amount of body fat in early adulthood.

Objective

To analyze the associations between DP tracking and changes in the period between 15 and 18 years of age and the percentage of body fat (%BF) at age 18 years.

Methods

We used data from 3,823 members of the 1993 Pelotas (Brazil) birth cohort. Body density was measured at age 18 years by air displacement plethysmograph (BOD POD) and the %BF was calculated applying the Siri equation. Based on the estimates from the FFQ, we identified DP at ages 15 (“Varied”, “Traditional”, “Dieting” and “Processed meats”) and 18 years (“Varied”, “Traditional”, “Dieting” and “Fish, fast food and alcohol”). The DP tracking was defined as the individual’s adherence to the same DP at both ages. Associations were tested using multiple linear regression models stratified by sex.

Results

The mean %BF was 25.0% (95% CI: 24.7 to 25.4), significantly greater for girls than boys (p<0.001). The adherence to any DP at age 15 years was not associated with the %BF at age 18 years. However, individuals who adhered to a “Dieting” DP at age 18 years showed greater %BF (1.30 and 1.91 percentage points in boys and girls, respectively) in comparison with those who adhered to a “Varied” DP. Boys who presented tracking of a “Dieting” DP presented greater average %BF in comparison with others DP, as well as girls who changed from the “Traditional” or “Processed meats” DP to a “Dieting” DP.

Conclusion

These results may support public health policies and strategies focused on improving dietary habits of adolescents and young adults and preventing accumulation of body fat, especially among the adolescents with restrictive dietary habits.