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Background: Some persons are genetically resistant to obesity, but only a few studies have evaluated thinness genes for preventing obesity. We aimed to investigate the association of polygenic variants with being underweight and their interaction with the lifestyles of middle‐aged and elderly persons and identify potential new genetic approaches for managing body weight. Methods: In total, 58,701 participants aged 40–77 years were recruited from urban hospitals in Korea. Underweight (case) was defined as body mass index (BMI) < 18.5 kg m2 (n = 991) and normal weight (control, n = 21,921) was defined as 18.5 ≤ BMI < 23 kg m2. A genome‐wide association study was run to identify thinness‐related single nucleotide polymorphisms (SNPs) after adjustment for compound factors using Gplink. The generalised multifactor dimensionality reduction program was used to identify the genetic variants with SNP–SNP interactions. The polygenic risk score (PRS) was calculated by summing up the number of risk alleles in each SNP and classifying them into low‐, medium‐ and high‐PRS. Results: The best model included the ANK2_rs7656666, CAST_rs28042, SLC1A3_rs928431867, CHST12_rs2906173, ALOX5_rs1051713, RGS6_rs17180754, ST8SIA5_rs79491311 and DCC_rs35721894 alleles. The participants with high‐PRS had a lower BMI (p < 0.0001) than those with low‐PRS and were 3.834 (2.58–5.70) times more likely to be underweight after multivariate adjustment (p < 0.001). The selected SNPs were correlated with each other and highly expressed in brain‐related genes. The genes with minor alleles of CAST_rs28042 and CHST12_rs2906173 exhibited a higher expression frequency in brain‐related tissues. PRS had significant interactions with protein, sodium, indigestible carbohydrates, calcium intake and exercise (p < 0.05), influencing the underweight state. People with a high‐PRS were more underweight than those with low‐PRS under high protein, sodium, high calcium, low indigestible carbohydrate intake and low exercise by 3.75, 3.88, 7.05, 3.18 and 3.80 times, respectively (p < 0.0001). Conclusions: In conclusion, adults having a high‐PRS were significantly correlated with being underweight, especially in combination with a particular nutritional status. These results show the potential for thinness genes to be applied to personalised nutrition for preventing obesity through targeted gene therapy. Highlights: There is less research on understanding the role of genetic mutations in maintaining underweight. The present study found that high‐risk scores of thinness‐related polygenic variants (PRS) were positively associated with being underweight by 3.83 times. PRS interacted with environmental factors, including protein, indigestible carbohydrates, sodium and calcium intake, as well as physical activity. The study clearly suggests that the discovery of single nucleotide polymorphism (SNP)–environment interactions by using PRS was notable for its influence on the state of being underweight. Therapies targeting these genes and the SNPs of PRS could help scientists prevent obesity and manage weight in the future. [ABSTRACT FROM AUTHOR]

Aims/Introduction: The incretin hormone glucose‐dependent insulinotropic polypeptide (GIP) is secreted after meal ingestion. This study explored the relative influence of classes of macronutrients on GIP secretion. Materials and Methods: The human literature was revisited by identifying articles from PubMed using key words GIP, macronutrients, carbohydrates, fat, protein, healthy subjects. In model experiments in anesthetized mice, glucose (25–125 mg), protein (15–120 mg), fat emulsion (6–100 mg) or saline was given orally with determination of GIP levels. Results: The literature survey identified 15 studies in which glucose, protein or fat was administered to healthy subjects. All three classes of macronutrients stimulated GIP secretion with a 30–45 min peak after glucose and protein, and a more prolonged release after fat. Limitations in study designs preclude firm conclusions on the relative potency of the macronutrients. In mice, glucose was more potent to stimulate GIP secretion than fat and protein, with no significant difference between protein and fat. By co‐administration of the macronutrients at moderate caloric combinations, a synergistic stimulation of GIP secretion was observed. In contrast, when raising the glucose challenge together with protein and fat, no synergy, but an additive effect, was evident. Conclusions: Glucose, protein and fat all stimulate GIP secretion in humans and mice. In mice, glucose is more potent than fat and protein, and there is also a synergy between the macronutrients on GIP secretion at moderate caloric doses. Further studies are warranted in humans to explore the relative potency of macronutrients. [ABSTRACT FROM AUTHOR]

The larvae of Zophobas atratus F. (Coleoptera: Tenebrionidae) are a promising source of dietary protein for animal feed. However, there has been no detailed investigation on macronutrient selection and requirement in Z. atratus larvae. Here, we used the geometric framework to explore the behavioural and physiological regulation of protein and carbohydrate in Z. atratus larvae. When provided with pairs of nutritionally imbalanced but complementary foods (choice experiment), Z. atratus larvae self‐composed a diet with a protein‐to‐carbohydrate (P:C) ratio of 1.47:1 or 1.19:1 throughout the experimental period. Across different choice combinations, the intake of carbohydrate was more tightly regulated than that of protein. When confined to one of six foods imbalanced with respect to P:C ratio (no‐choice experiment), Z. atratus larvae regulated their protein–carbohydrate intake to form linear intake arrays across nutrient space in a manner similar to those previously described for other nutritional generalists. The negative slope of the linear intake arrays was shallow (−0.67 to −0.54), suggesting that protein was over‐consumed by Z. atratus larvae to a greater extent than carbohydrates. The nutritional landscapes fitted for larval performance traits exhibited that the performance of Z. atratus larvae was maximized at the P:C ratio of 2:1 and fell rapidly as the P:C ratio decreased below 1:1. There was evidence for post‐ingestive regulation for body nutrient growth through adjusting the utilization efficiencies of ingested protein and carbohydrate. Our results represent the most comprehensive analysis of macronutrient regulation in Z. atratus and have implications for designing an optimal diet for this beneficial insect. [ABSTRACT FROM AUTHOR]

Multivoltine insects can produce multiple generations in one year. Favorable conditions support more generations, leading to serious outbreaks. For herbivores, plant nutrient availability is a major environmental factor affecting fitness and it can shift substantially throughout seasons. In a stochastic environment, organisms can adopt several strategies to regulate their nutrient intake and maximize performance. However, data regarding nutrient regulation of wild herbivores are scarce, and even more so regarding potential intergenerational plasticity. To bridge this gap, we measured nutritional regulation and performance of an outbreaking multivoltine herbivore – one of the most serious agricultural pests in the Sahel: Oedaleus senegalensis. We surveyed a field population in Senegal and measured its nutritional preference and regulation across two generations (G1 and G3) using artificial diets and plant choice experiments. In the field, G1 locusts were five to ten times more abundant than G3 locusts. We found that G1 and G3 locusts selected different protein:carbohydrate ratios but also that the strength of regulation was different. G1 locusts regulated their nutrient target more tightly than G3 locusts. In contrast, studies with laboratory populations demonstrate strong regulation for grasshoppers, appearing less plastic than field populations. Both generations selected a carbohydrate‐biased nutrient ratio, although it was more carbohydrate‐biased for G3 locusts. In both cases, plant nutrient contents in the field were more protein biased than their preferred diet. Therefore, choices by locusts were likely influenced by other ecological variables such as leaf toughness or plant defenses. G1females were heavier and laid more eggs than G3 females. However, G3 locusts survived longer during the experiment than G1 locusts, suggesting a potential generational tradeoff between reproduction and survival. Our data highlight the importance of studying nutritional regulation in situ and incorporating field and lab data to better understand foraging decisions and nutritional tradeoffs. [ABSTRACT FROM AUTHOR]

Most organisms must regulate their nutritional intake in an environment full of complex food choices. While this process is well‐understood for self‐sufficient organisms, dependent offspring, such as bee larvae, in practice have limited food choices because food is provided by parents. Nutrient balancing may therefore be achieved by offspring, by parents on offspring's behalf, or by both, whether cooperatively or in conflict.We used the Geometric Framework to investigate the capacity of dependent larval mason bees Osmia bicornis to regulate their intake of protein and carbohydrate, as well as these nutrients' effects upon growth and survival. Female Osmia seal eggs individually inside cells they have provisioned with pollen, and have no contact with developing offspring, allowing offspring choices to be studied in isolation. Herbivorous insect larvae are typically expected to balance protein and carbohydrate to maximize growth and reproduction.Contrary to prediction, carbohydrate and not protein mediated both growth and survival to pupation. Accordingly, larvae prioritized maintaining a constant intake of carbohydrate and self‐selected a relatively carbohydrate‐biased diet compared to other hymenopterans, while tolerating wide excesses and deficiencies of protein, rendering them potentially vulnerable to dietary change or manipulation. Reasons for prioritizing carbohydrate may include (a) the relative abundance of protein in their normal pollen diet, (b) the relative paucity of nectar in parental provisions making carbohydrate a scarce resource or (c) the requirement for diapause for all O. bicornis larvae. Larvae were intolerant of moderate dietary dilution, likely reflecting an evolutionary history of nutrient‐dense food.Our results demonstrate that dependent offspring can remain active participants in balancing their own nutrients even when sedentary, and, moreover, even in mass provisioning systems where parents and offspring have no physical contact. Research should now focus on whether and how evolutionary interests of parent and dependent offspring coincide or conflict with respect to food composition, and the implications for species' resilience to changing environments. A free Plain Language Summary can be found within the Supporting Information of this article. [ABSTRACT FROM AUTHOR]

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Nitrogen limitation theory predicts that terrestrial plants should benefit from nitrogen inputs and that herbivores should benefit from subsequent higher plant protein contents. While this pattern has generally been supported, some herbivorous insects have shown preference and higher performance on low protein (p), high carbohydrate (c) diets as juveniles.However, little is known about the effects on reproduction in adults. Using nitrogen fertilizer, we demonstrate that high plant p:c has negative effects on Senegalese locust (Orthoptera: Oedaeleus senegalensis) reproduction and survival in an agroecological setting.For this, we measured p:c in millet plants Pennisetum glaucum that received two levels of fertilizer (high and moderate) and a control, then we caged locusts on these plants for 2 weeks. In the laboratory, we gave locusts the choice between untreated millet leaves and leaves that received one of the two fertilization treatment.We found that fertilization increased p:c ratio in a concentration‐dependent fashion. We counted the number of locusts alive over the course of 2 weeks and showed that fewer females survived on fertilized plants than on control plants. Females that ate plants from the high fertilization treatment laid lighter eggs. Finally, we showed that female locusts prefer unfertilized plants to plants with a high p:c.We hypothesize that this pattern will apply broadly to species that have extensive carbohydrate needs, such as long‐distance migrators. Because many ecological studies focus primarily on nitrogen or protein, and fail to consider carbohydrates, this study has important implications for how ecologists consider nutrient limitation of primary consumers in ecosystems globally. [ABSTRACT FROM AUTHOR]

Access to high‐quality food is a main driver of population dynamics. For herbivores, protein and carbohydrates are key nutrients that are notoriously variable in plants and are affected by land use. However, few studies have linked foraging decisions and performance in the laboratory to the nutritional landscape available in the field.Oedaleus senegalensis is a non‐model locust, a grass‐feeder, and the main pest of millet, a subsistence crop in the Sahel. In this study, we examined dietary preference and locust performance across a range of protein:carbohydrate ratios using the Geometric Framework methodology. We then applied a fitness landscape approach to visualize these results with the plant nutrient contents available across four land‐use types: millet, groundnut, fallow, and grazed fields. Finally, we contrasted our results with locust distribution in the field. Several locust species (O. senegalensis included) exhibit density‐dependent colour polymorphism; thus, we also reported individual coloration (brown or green).We found that O. senegalensis preferred moderately carbohydrate‐biased food 1:1.6 protein:carbohydrate ratio. All traits recorded (mass gain, development time, growth rate, moult success and performance index) were best near that ratio and declined on either side presenting a 'hump‐shape'. Fallow fields contained more plants, particularly grasses, that were both abundant and closer to the optimal protein:carbohydrate ratio recorded from the laboratory experiments.When we surveyed O. senegalensis abundance and proportion, we found that they were more numerous in the fallow fields. Brown morph individuals, the ones associated with high density, were proportionally more abundant in fallow fields than green individuals.Our study provides evidence that variation in nutritional landscapes – relative to an herbivore's optimal nutrient balance – is a key driver of herbivore population distribution and abundance, and can be used to predict bottom‐up effects on herbivore species. [ABSTRACT FROM AUTHOR]

The macromolecular composition of macroalgae influences nutrient flow and food quality in aquatic ecosystems and the value of macroalgae species for human consumption, aquaculture, biofuels, and other applications. We used literature data (125 publications, 1,117 observations) and a hierarchal Bayesian statistical model to estimate the average macromolecular composition, protein, lipid, and carbohydrate of macroalgae as a whole and at the phylum level. Our focus was on marine, noncalcified macroalgae sampled from wild‐grown populations in the field. We found that the median macromolecular composition is 9.98% protein, 2.7% lipid, 48.5% carbohydrate, and 31.8% ash as percent dry weight. We compared the median macromolecular content of macroalgae to microalgae and herbaceous plants and test for differences in macromolecular content across macroalgal phyla. Macroalgae were much more enriched in carbohydrate and minerals than the microalgae and lower in protein and lipid than many herbaceous plants. Rhodophyte macroalgae have significantly less lipid and more protein and the Ochrophyte macroalgae have significantly less protein than the average. [ABSTRACT FROM AUTHOR]

Invasive animals depend on finding a balanced nutritional intake to colonize, survive, and reproduce in new environments. This can be especially challenging during situations of fluctuating cold temperatures and food scarcity, but phenotypic plasticity may offer an adaptive advantage during these periods. We examined how lifespan, fecundity, pre‐oviposition periods, and body nutrient contents were affected by dietary protein and carbohydrate (P:C) ratios at variable low temperatures in two morphs (winter morphs WM and summer morphs SM) of an invasive fly, Drosophila suzukii. The experimental conditions simulated early spring after overwintering and autumn, crucial periods for survival. At lower temperatures, post‐overwintering WM lived longer on carbohydrate‐only diets and had higher fecundity on low‐protein diets, but there was no difference in lifespan or fecundity among diets for SM. As temperatures increased, low‐protein diets resulted in higher fecundity without compromising lifespan, while high‐protein diets reduced lifespan and fecundity for both WM and SM. Both SM and WM receiving high‐protein diets had lower sugar, lipid, and glycogen (but similar protein) body contents compared to flies receiving low‐protein and carbohydrate‐only diets. This suggests that flies spend energy excreting excess dietary protein, thereby affecting lifespan and fecundity. Despite having to recover from nutrient depletion after an overwintering period, WM exhibited longer lifespan and higher fecundity than SM in favorable diets and temperatures. WM exposed to favorable low‐protein diet had higher body sugar, lipid, and protein body contents than SM, which is possibly linked to better performance. Although protein is essential for oogenesis, WM and SM flies receiving low‐protein diets did not have shorter pre‐oviposition periods compared to flies on carbohydrate‐only diets. Finding adequate carbohydrate sources to compensate protein intake is essential for the successful persistence of D. suzukii WM and SM populations during suboptimal temperatures. At lower temperatures, Drosophila suzukii females do not invest in reproduction and benefit from a carbohydrate‐only diet. With increasing temperatures, low‐protein diets are optimal for fecundity without compromising lifespan. High‐protein diets are detrimental. Post‐overwintering WM have higher lipid and sugar body content than SM and increased lifespan and fecundity. [ABSTRACT FROM AUTHOR]

Silver nanoparticles (AgNPs) have attracted the attention of researchers due to their properties. Biological synthesis of AgNPs is eco‐friendly and cost‐effective preferred to physical and chemical methods, which utilize environmentally harmful agents and large amounts of energy. Microorganisms have been explored as potential biofactories to synthesize AgNPs. Bacterial NP synthesis is affected by Ag salt concentration, pH, temperature and bacterial species. In this study, Bacillus spp., isolated from soil, were screened for AgNP synthesis at pH 12 with 5 mM Ag nitrate (AgNO3) final concentration at room temperature. The isolate with fastest color change and the best ultraviolet‐visible spectrum in width and height were chosen as premier one. AgNO3 and citrate salts were compared in terms of their influence on NP synthesis. Spherical Ag chloride (AgCl) NPs with a size range of 35–40 nm were synthesized in 1.5 mM Ag citrate solution. Fourier transform infrared analysis demonstrated that protein and carbohydrates were capping agents for NPs. In this study, antimicrobial and antitumor properties of the AgNP were investigated. The resulting AgCl NPs had bacteriostatic activity against four standard spp. And multi‐drug resistant strain of Pseudomonas aeruginosa. These NPs are also cytotoxic to cancer cell lines MCF‐7, U87MG and T293. [ABSTRACT FROM AUTHOR]

Abstract: Since its arrival to North America less than a decade ago, the invasive Spotted‐Wing Drosophila (Drosophila suzukii) has inflicted substantial economic losses on soft fruit agriculture due to its ability to oviposit into ripening fruits. More effective management approaches for this species are needed, but little is known about the factors that influence behavioral choices made by D. suzukii when selecting hosts, or the consequences that their offspring experience when developing in different environments. Using a nutritional geometry methodology, we found that the ratio of proteins‐to‐carbohydrates (P:C) present in media greatly influenced adult D. suzukii behavior and subsequent offspring development. Whereas adult flies showed a strong bias in their oviposition and association behaviors toward carbohydrate‐rich foods, larval survival and eclosion rate were strongly dependent on protein availability. Here, we explore the preference–performance hypothesis (PPH), in which females are predicted to oviposit on medias that provide the greatest offspring benefits, in regard to its relevance in D. suzukii behavior and consequences for management. Our results provide valuable insight into the ecology and evolution of this species that may hopefully lead to more effective management strategies. [ABSTRACT FROM AUTHOR]

Incubations were carried out with batch cultures of ruminal micro-organisms from sheep to analyse the influence of the N source on in vitro CH4 production. The two substrates were mixtures of maize starch and cellulose in proportions of 75:25 and 25:75 ( STAR and CEL substrates, respectively), and the three nitrogen (N) sources were ammonia ( NH4Cl), casein ( CA) and isolated soya bean protein ( SP). Five isonitrogenous treatments were made by replacing non-protein-N ( NPN) with CA or SP at levels of 0 ( NPN), 50 ( CA50 and SP50, respectively) and 100% ( CA100 and SP100) of total N. All N treatments were applied at a rate of 35 mg of N/g of substrate organic matter and incubations lasted 16.5 h. With both proteins, N source × substrate interactions (p = 0.065 to 0.002) were detected for CH4 production and CH4/total VFA ratio. The increases in CH4 production observed by replacing the NPN with protein-N were higher (p < 0.05) for STAR than for CEL substrate, but the opposite was observed for the increases in volatile fatty acid ( VFA) production. As a consequence, replacing the NPN by increased levels of CA or SP led to linear increases (p < 0.05) in CH4/total VFA ratio with STAR, whereas CH4/total VFA ratio tended (p < 0.10) to be decreased with CEL substrate. Increasing the amount of both proteins decreased linearly (p < 0.05) ammonia-N concentrations, which may indicate an incorporation of amino acids and peptides into microbial protein without being first deaminated into ammonia-N. In incubations with the tested N sources as the only substrate, the fermentation of 1 mg of CA or SP produced 1.24 and 0.60 μmol of CH4 respectively. The results indicate the generation of CH4 from protein fermentation, and that the response of CH4 production to protein-N supply may differ with the basal substrate. [ABSTRACT FROM AUTHOR]

Carbonyl sulphide ( COS) is a potential tracer of gross primary productivity ( GPP), assuming a unidirectional COS flux into the vegetation that scales with GPP. However, carbonic anhydrase ( CA), the enzyme that hydrolyses COS, is expected to be light independent, and thus plants without stomata should continue to take up COS in the dark., We measured net CO2 ( AC) and COS ( AS) uptake rates from two astomatous bryophytes at different relative water contents ( RWCs), COS concentrations, temperatures and light intensities., We found large AS in the dark, indicating that CA activity continues without photosynthesis. More surprisingly, we found a nonzero COS compensation point in light and dark conditions, indicating a temperature-driven COS source with a Q10 (fractional change for a 10°C temperature increase) of 3.7. This resulted in greater AS in the dark than in the light at similar RWC. The processes underlying such COS emissions remain unknown., Our results suggest that ecosystems dominated by bryophytes might be strong atmospheric sinks of COS at night and weaker sinks or even sources of COS during daytime. Biotic COS production in bryophytes could result from symbiotic fungal and bacterial partners that could also be found on vascular plants. [ABSTRACT FROM AUTHOR]

In many insect species, the differentiation of development between diapause and reproduction first becomes obvious during the diapause preparation (pre-diapause) and pre-oviposition phases. However, the differentiation of nutrient accumulation between these two phases remains unclear. We compared the weights of pre-diapause and reproductive adult female Colaphellus bowringi Baly ( Coleoptera: Chrysomelidae), and measured their triacylglycerol ( TAG), protein, and carbohydrate content from emergence until they had fed for 4 days post-eclosion. We also compared the ovarian development and accumulation of lipid droplets between pre-diapause and reproductive adult females in order to determine whether we could visually detect differences in nutrient allocation. The weights of both pre-diapause and reproductive females increased with duration of feeding. The fresh weight and water content of pre-diapause females was significantly lower than that of reproductive females after feeding for 3 days post-eclosion. Pre-diapause females channeled their reserves into TAG in the fat body, whereas reproductive females converted nutrients into proteins and carbohydrates for egg development. These results quantify differences in nutrient accumulation between pre-diapause and reproductive adult female C. bowringi, and provide clues for understanding the molecular mechanisms underlying differences in the allocation of nutrients between diapause and reproduction in insects. [ABSTRACT FROM AUTHOR]

The growth rates of insect herbivores commonly decrease when they feed on mature leaves due to the combined effects of several nutritional and physiological mechanisms. Environmental stresses during leaf development may also decrease herbivore performance. The present study tests two main hypotheses to help clarify the importance of these factors for the nutrition and growth of an insect herbivore: (i) decreases in nutrient levels, consumption rates and nutrient assimilation efficiencies impact negatively on herbivores feeding on mature leaves and (ii) wind stress has a negative impact on herbivores feeding on mature leaves. The results show that mature poplar ( Populus alba × Populus tremula) leaves have decreased levels of protein and increased levels of fibre, and that growth rates of gypsy moth ( Lymantria dispar L.) are decreased on mature leaves in association with decreased consumption rates. However, in contrast to the first hypothesis, protein and carbohydrate are assimilated efficiently (74-82% and 84-87%, respectively) from immature and mature poplar leaves. The larvae are able to chew mature leaves as efficiently as immature leaves, potentially maximizing nutrient extraction. By contrast to the second hypothesis, wind-stressed leaves have no significant detrimental effects on nutrient assimilation efficiencies, and the lower growth rates of L. dispar larvae feeding on mature wind-stressed leaves can be explained by lower consumption rates. Therefore, the availability of nutrients to herbivores feeding on mature tree leaves is not necessarily impacted by lower assimilation efficiencies, even when leaves develop under wind stress. These results help explain some of the large variation between the nutritional qualities of trees for forest Lepidoptera. [ABSTRACT FROM AUTHOR]

The efficient aquisition of nutrients from leaves by insect herbivores increases their nutrient assimilation rates and overall fitness. Caterpillars of the gypsy moth (Lymantria dispar L.) have high protein assimilation efficiencies (PAE) from the immature leaves of trees such as red oak (Quercus rubra) and sugar maple (Acer saccharum) (71-81%) but significantly lower PAE from their mature leaves (45-52%). By contrast to this pattern, both PAE and carbohydrate assimilation efficiencies (CAE) remain high for L. dispar larvae on the mature leaves of poplar (Populus alba × Populus tremula) grown in greenhouse conditions. The present study tests two alternative hypotheses: (i) outdoor environmental stresses cause decreased nutrient assimilation efficiencies from mature poplar leaves and (ii) nutrients in the mature leaves of trees in the poplar family (Salicaceae) remain readily available for L. dispar larvae. When poplar trees are grown in ambient outdoor conditions, PAE and CAE remain high (approximately 75% and 78%, respectively) in L. dispar larvae, in contrast to the first hypothesis. When larvae feed on the mature leaves of species in the Salicaceae [aspen (Populus tremuloides), cottonwood (Populus deltoides), willow (Salix nigra) and poplar], PAE and CAE also remain high (68-76% and 72-92%, respectively), consistent with the second hypothesis. Larval growth rates are strongly associated with protein assimilation rates, and more strongly associated with protein assimilation rates than with carbohydrate assimilation rates. It is concluded that tree species in the Salicaceae are relatively high-quality host plants for L. dispar larvae, in part, because nutrients in their mature leaves remain readily available. [ABSTRACT FROM AUTHOR]

Declines in insect pollinators in Europe have been linked to changes in land use. Pollinator nutrition is dependent on floral resources (i.e., nectar and pollen), which are linked to landscape composition. Here, we present a stratified analysis of the nutritional composition of beebread in managed honeybee hives with a view to examining potential sources of variation in its nutritional composition. Specifically, we tested the hypothesis that beebread composition correlates with local land use and therefore available floral resources. The results demonstrated that the starch, lipid, and moisture contents of beebread are all highly conserved across hives, whereas levels of protein and nonreducing sugar increased as the year progressed, reducing sugars, however, decreased during the first half of the year and then increased toward the end. Local land use around hives was quantified using data from the Countryside Survey 2007 Land Cover Map. Bee-bread protein content was negatively correlated with increasing levels of arable and horticultural farmland surrounding hives and positively correlated with the cover of natural grasslands and broadleaf woodlands. Reducing sugar content was also positively correlated with the amount of broad-leaved woodland in a 3 Km2 radius from the hives. Previous studies on a range of invertebrates, including honeybees, indicate that dietary protein intake may have a major impact on correlates of fitness, including longevity and immune function. The finding that beebread protein content correlates with land use suggests that landscape composition may impact on insect pollinator well-being and provides a link between landscape and the nutritional ecology of socially foraging insects in a way not previously considered. [ABSTRACT FROM AUTHOR]

The growing interest in food component interactions, especially the solid-state protein-carbohydrate ones, has led to a growing body of knowledge on the effects of these interactions on the physical, chemical, and structural properties of compositionally complex food systems. The goal of the present review is to survey the critical mechanisms involved in protein-carbohydrate interactions as a key step toward the rational formulation and processing of protein- and carbohydrate-rich foods to produce products with desirable properties without adverse reactions. The hypotheses proposed on the stabilizing effects of carbohydrates on proteins and the role of different types of sugars in the extent of these interactions are reviewed in this article. Another aspect of this review involves the successful drying of proteins by spray-drying, freeze-drying, and supercritical-fluid-drying using carbohydrates. Finally, applications of these interesting phenomena to produce important food products including milk powder, infant formulas, bakery products, and fruit and vegetable juice powders are investigated. [ABSTRACT FROM AUTHOR]

With the growing demand for bio-based materials, the present study investigates the use of soy flour (SF) as potential reinforcement in thermoplastic elastomers (TPEs). Soy and poly(styrene-butadiene-styrene) triblock copolymer composite films are prepared using conventional thermoplastic polymer processing techniques. These composite films are investigated to evaluate the influence of SF concentration on the thermo-mechanical and rheological properties. The results suggest that environmentally friendly soy flour reinforced thermoplastic elastomers exhibit excellent properties and offer great potential to replace traditional synthetic elastomeric materials. [ABSTRACT FROM AUTHOR]

This study investigated the influence of surface-inactive carbohydrates on association characteristics of amphiphilic mung bean protein hydrolysate ( MPH) and asiatic acid ( AA) in aqueous suspension (11.72-11.94% total solids). The carbohydrates investigated were trehalose, maltodextrin, mixed trehalose-maltodextrin and mixed maltodextrin-starch. The presence of low-molecular-weight carbohydrates enhanced micellisation of AA to form micrometre-sized particles due to depletion flocculation. Nonetheless, the presence of starch retained the submicrometre size of AA. In contrast, the presence of starch enhanced self-association of MPH via segregative phase separation. However, the mixed suspensions containing MPH, AA and carbohydrate in a ratio of 1:0-0.072:2.34, respectively, retained particle sizes of around 300 nm regardless of the carbohydrate used. It was found that the MPH- AA co-aggregates were stable against the osmotic effect of carbohydrates. The results suggest that carbohydrates regulated the aggregate size and surface hydrophobic region of MPH and MPH- AA by controlling surface-induced aggregation. [ABSTRACT FROM AUTHOR]

The soybean [ Glycine max (L.) Merr.] is grown worldwide for its high protein and oil contents. Characterization of soybean seed components lends itself to understanding how soybean production can meet the needs of a growing world population. For this article, literature was reviewed and condensed to create a well-rounded picture of the current understanding of structural, functional, and nutritional properties of soybean components. Natural variation in soybean protein, lipid, and carbohydrate components, as well as the minor constituents phytic acid and isoflavones, are mentioned. Environment- or genetic-induced shifts in natural variation are described with respect to nutrition and functional improvements in soybean. [ABSTRACT FROM AUTHOR]

It is well recognised that ingestion of food is a trigger for functional bowel symptoms, particularly those associated with irritable bowel syndrome ( IBS). Patients often use manipulation of diet as a means of controlling symptoms. Despite description of multiple dietary methods, few have scientific backing or quality evidence of efficacy. One approach is to define how specific food components influence the pathophysiology of IBS and then rationally design dietary approaches. For example, short-chain poorly absorbed carbohydrates (fermentable oligo-, di- and mono-saccharides and polyols ( FODMAP)) cause luminal distension, which is a major stimulus for the development of symptoms in patients with visceral hypersensitivity. By determining food content of FODMAP, a diet in which foods low in FODMAP are favoured over those high in FODMAP can be designed. Observational, comparative and randomised controlled treatment and rechallenge studies have shown that such an approach is efficacious in the majority of patients with IBS. The low FODMAP diet is now the primary dietary therapy for such patients. Similar approaches can be applied to other food components, including proteins (such as gluten), fats and natural bioactive food chemicals. Such approaches have suggestions of efficacy, but the evidence base remains underdeveloped. An additional and important consideration for any dietary therapy is its nutritional adequacy and potential adverse health effects. Dietary manipulation is now a key management strategy in patients with functional bowel symptoms. Future well-designed interventional studies will lead to refinement of dietary approaches taken and to a better understanding of their long-term safety. [ABSTRACT FROM AUTHOR]

The geometric framework provides a way for understanding the multi-dimensional nutritional relationships between consumers and their food. We use this approach to further our understanding of the feeding and nutritional ecology of a ubiquitous mixed-feeding insect herbivore that consumes a variety of host plants spanning a wide range of nutritional composition. Our overall objective was to examine feeding decisions, resulting performance, and post-ingestive consequences in a common mixed-feeding insect herbivore, Melanoplus bivittatus ( Say) ( Orthoptera: Acrididae), when presented with paired diets differing in protein:carbohydrate (p:c) ratio. Intake p:c of M. bivittatus differed among all but two treatments and in many cases was farther than expected from the previously identified p:c intake target for this species. Despite this variability in intake of protein and carbohydrate, we found few effects of the diet treatments on performance or post-ingestive processing. However, our results suggest that when feeding on high-quality diets, nutrients consumed in excess may be stored rather than excreted. [ABSTRACT FROM AUTHOR]

Background: When substituted for carbohydrate in a meal, dietary protein enhances glycaemic control in subjects with type 2 diabetes (DM2). It is unknown whether the effect is a result of increased protein or reduced carbohydrate. The present study aimed to compare the effects of two meals differing in protein to fat ratios on post-prandial glucose and insulin responses. Methods: This was a crossover, blind study in which obese subjects with ( n = 23) and without ( n = 26) DM2 consumed two meals in random order with equal amounts of energy (3.1 MJ, 741 kcal), fibre and carbohydrates and a 1-week washout period. Meals were a high protein, low fat (30% protein, 51% carbohydrates, 19% fat) meal and a low protein, high fat (15% protein, 51% carbohydrates, 34% fat) meal. Subjects were matched for age and body mass index. Plasma glucose and insulin were measured at fasting, 30, 60, 90, 120 min post-prandially. Insulin resistance and insulin sensitivity were assessed. Results: There was no significant meal effect on glucose and insulin responses within groups. Glucose response was higher in diabetic (120 min 11 ± 0.7 mmol L−1) compared to nondiabetic (120 min 5 ± 0.2; P < 0.001) subjects. Diabetic subjects had significantly higher insulin resistance ( P < 0.001) and lower insulin sensitivity ( P < 0.001) than nondiabetics. Although peak insulin levels, 60 min post-prandially, did not differ between groups (81 ± 9 pmol L−1 for diabetic versus 79 ± 7 pmol L−1 for nondiabetic subjects), they were achieved much later, 90 min post-prandially, in diabetic, (99 ± 8 pmol L−1) compared to nondiabetic (63 ± 7 pmol L−1, P = 0.002) subjects. Conclusions: Manipulating protein to fat ratio in meals does not affect post-prandial plasma blood glucose or insulin responses in obese people with and without DM2. [ABSTRACT FROM AUTHOR]

Using the geometric framework for the first time in a field study of ant nutritional biology, we show that Ectatomma ruidum colonies actively regulate protein–carbohydrate intake, self-selecting a carbohydrate-biased diet. These data, combined with quantitative recruitment data, provide a more comprehensive understanding of colony-level nutritional requirements of ants. Abstract in Spanish is available at [ABSTRACT FROM AUTHOR]

Food availability often influences competitive outcomes through effects on consumer growth. Although it has received less attention, food availability may also affect competition through nutritional effects on behavior. One hypothesis linking nutrition and competition in ants posits that increased access to carbohydrates favors greater investment in worker traits that underlie behavioral dominance. We tested this hypothesis by varying dietary protein: carbohydrate (P:C) ratios and levels of interspecific interference for Argentine ants (Linepithema humile), a widespread invasive species. As predicted, colonies facing interference increased patrolling more when reared on low P:C diets; this result is the first demonstration of an interactive effect of nutrition and interference on ant colonies. Several results suggest that this dietary effect on patrolling was due primarily to changes in colony size rather than worker behavior. Colonies on lower P:C diets had lower worker mortality and larger final colony sizes. Diet had little effect on per capita patrolling, and worker behavior in performance assays depended more on previous exposure to interference than on diet. Our findings indicate that dietary P:C rations can influence Argentine ant performance in a competitive environment and suggest a mechanism by which monopolization of carboyhydrate-rich sources can help invasive ants display native ant competitors. [ABSTRACT FROM AUTHOR]

We estimate the income elasticity for a variety of macro- and micronutrients using a sample of poor rural households in Mexico. The nutrient-income elasticity is estimated using both parametric and semiparametric methods. A special focus is placed on the nonlinearity of the relationship between nutrient intake and income and on measurement error and endogeneity issues. One major finding is that income elasticity for calories is close to zero when we control for measurement error issues. For some nutrients, namely fats, vitamin A and C, calcium, and heme iron, we find a sizeable positive income elasticity robust to the choice of the estimator and percentiles at which it is evaluated. These nutrients are also those for which we find the largest deficiency in our sample. In addition, we find that for the poorest households in our sample, the deficiency of total energy, protein, and zinc is not accompanied by a positive income elasticity. [ABSTRACT FROM AUTHOR]

Raphidiopsis brookii P. J. Hill (cyanobacteria) was isolated from a small subtropical eutrophic pond (Biguá Pond) located in the grounds of Rio Grande University in the extreme south of Brazil, following a toxic bloom of this species. Growth, saxitoxin production, and release of carbohydrates and protein were monitored at three sodium nitrate concentrations (500, 1,000, and 1,500 μM), from inoculation up to the stationary growth phase. Growth was monitored by determining the biovolume, chl content, and trichome count. Growth was better described in terms of biovolume and chl measurements, because trichome fragmentation was observed to increase at the stationary growth phase. Carbohydrates and proteins were released in small amounts during most of the experiment, with a significant increase during the stationary phase. Extracellular polysaccharides were essentially composed of glucose, galactose, N-acetyl-glucosamine, mannose, xylose, rhamnose, arabinose, and fucose. The relative proportions of these units showed no significant variation during growth. Small quantities of extracellular free carbohydrates were also detected, and only fucose was released in significant amounts at the lowest nitrate concentration (500 μM). R. brookii produced both saxitoxin and dc-saxitoxin, the former at four times the rate of the latter. This was the first study demonstrating saxitoxin production and the release of both carbohydrate and protein by R. brookii. [ABSTRACT FROM AUTHOR]

There is an emerging interest in the impact of food structure on digestion behaviour and its relationship to human nutrition. The interactions between individual macronutrients (protein, fat and carbohydrate) in many cases control the rate of digestive processes such as proteolysis and lipolysis. Macronutrient interactions can also control the material properties of ingested foods which can influence post-prandial metabolic responses. This review summarises the current research into how the structure of individual macronutrients impacts digestion and how this relates to appetite. [ABSTRACT FROM AUTHOR]

Dietary protein induces greater satiety compared with carbohydrate in lean subjects, which may involve appetite-regulatory gut hormones. Little is known about the duration of effect, influence of protein and carbohydrate source and relevance to non-lean individuals. We compared the effect of various dietary proteins and carbohydrates on post-prandial appetite ratings, ad libitum energy intake (EI) and appetite hormones in lean and overweight men. Three randomised double-blinded cross-over studies examined appetite response (appetite ratings, ghrelin, glucagon-like peptide-1 (GLP-1) and cholecystokinin) to liquid preloads over three to four hours followed by a buffet meal to assess ad libitum EI. The 1-MJ preloads contained ∼55 g of protein (whey, casein, soy and gluten), carbohydrate (glucose, lactose and fructose) or combined whey/fructose. EI was 10% higher following glucose preloads compared with protein preloads, observed at three hours but not four hours. Protein ingestion was followed by prolonged elevation of cholecystokinin and GLP-1 (two hours) and suppression of ghrelin (three to four hours) compared with glucose and independent of protein type. Replacing some whey with fructose attenuated the effect of protein on these hormones. Treatment effects on EI and appetite hormones were independent of bodyweight status, despite higher GLP-1 and lower ghrelin in overweight subjects. Protein-rich liquid preloads reduce EI over three hours in overweight men compared with glucose. These findings suggest a potential application for protein-rich drinks and/or foods to facilitate reduced EI. Future studies should explore additional dietary manipulations that may enhance this relationship, and confirm these effects within the context of energy-restricted dietary patterns. [ABSTRACT FROM AUTHOR]

Extrusion cooking, as a multi-step, multi-functional and thermal/mechanical process, has permitted a large number of food applications. Effects of extrusion cooking on nutritional quality are ambiguous. Beneficial effects include destruction of antinutritional factors, gelatinisation of starch, increased soluble dietary fibre and reduction of lipid oxidation. On the other hand, Maillard reactions between protein and sugars reduce the nutritional value of the protein, depending on the raw material types, their composition and process conditions. Heat-labile vitamins may be lost to varying extents. Changes in proteins and amino acid profile, carbohydrates, dietary fibre, vitamins, mineral content and some non-nutrient healthful components of food may be either beneficial or deleterious. The present paper reviews the mechanisms underlying these changes, as well as the influence of process variables and feed characteristics. Mild extrusion conditions (high moisture content, low residence time, low temperature) improve the nutritional quality, while high extrusion temperatures (⩾200 °C), low moisture contents (<15%) and/or improper formulation (e.g. presence of high-reactive sugars) can impair nutritional quality adversely. To obtain a nutritionally balanced extruded product, careful control of process parameters is essential. [ABSTRACT FROM AUTHOR]

The chemical composition of organisms in relation to their environmental resource availability is an area of intense research activity. We studied the changes in cell composition of the cyanobacterium Phormidium autumnale in response to prolonged darkness. Cells allocated their internal resources in a homeostatic manner, oxidizing all the three major cellular constituents in a proportional way. This resulted in constant C/N and carbohydrates, lipids and proteins ratios that remained unaltered throughout the whole incubation period. We propose the maintenance of balanced cell composition (homeostasis) as an evolutionary strategy related to environmental transitory changes. [ABSTRACT FROM AUTHOR]

Grasses with the C3 photosynthetic pathway are commonly considered to be more nutritious host plants than C4 grasses, but the nutritional quality of C3 grasses is also more greatly impacted by elevated atmospheric CO2 than is that of C4 grasses; C3 grasses produce greater amounts of nonstructural carbohydrates and have greater declines in their nitrogen content than do C4 grasses tinder elevated CO2. Will C3 grasses remain nutritionally superior to C4 grasses under elevated CO2 levels? We addressed this question by determining whether levels of protein in C3 grasses decline to similar levels as in C4 grasses, and whether total carbohydrate: protein ratios become similar in C3 and C4 grasses under elevated CO2. In addition, we tested the hypothesis that, among the nonstructural carbohydrates in C3 grasses, levels of fructan respond most strongly to elevated CO2. Five C3 and five C4 grass species were grown from seed in outdoor open-top chambers at ambient (370 ppm) or elevated (740 ppm) CO2 for 2 months. As expected, a significant increase in sugars, starch and fructan in the C3 grasses under elevated CO2 was associated with a significant reduction in their protein levels, while protein levels in most C4 grasses were little affected by elevated CO2. However, this differential response of the two types of grasses was insufficient to reduce protein in C3 grasses to the levels in C4 grasses. Although levels of fructan in the C3 grasses tripled under elevated CO2, the amounts produced remained relatively low, both in absolute terms and as a fraction of the total nonstructural carbohydrates in the C3 grasses. We conclude that C3 grasses will generally remain more nutritious than C3 grasses at elevated CO2 concentrations, having higher levels of protein, nonstructural carbohydrates, and water, but lower levels of fiber and toughness, and lower total carbohydrate:protein ratios than C4 grasses. [ABSTRACT FROM AUTHOR]

Grasses with the C3 photosynthetic pathway are commonly considered to be more nutritious host plants than C4 grasses, but the nutritional quality of C3 grasses is also more greatly impacted by elevated atmospheric CO2 than is that of C4 grasses; C3 grasses produce greater amounts of nonstructural carbohydrates and have greater declines in their nitrogen content than do C4 grasses tinder elevated CO2. Will C3 grasses remain nutritionally superior to C4 grasses under elevated CO2 levels? We addressed this question by determining whether levels of protein in C3 grasses decline to similar levels as in C4 grasses, and whether total carbohydrate: protein ratios become similar in C3 and C4 grasses under elevated CO2. In addition, we tested the hypothesis that, among the nonstructural carbohydrates in C3 grasses, levels of fructan respond most strongly to elevated CO2. Five C3 and five C4 grass species were grown from seed in outdoor open-top chambers at ambient (370 ppm) or elevated (740 ppm) CO2 for 2 months. As expected, a significant increase in sugars, starch and fructan in the C3 grasses under elevated CO2 was associated with a significant reduction in their protein levels, while protein levels in most C4 grasses were little affected by elevated CO2. However, this differential response of the two types of grasses was insufficient to reduce protein in C3 grasses to the levels in C4 grasses. Although levels of fructan in the C3 grasses tripled under elevated CO2, the amounts produced remained relatively low, both in absolute terms and as a fraction of the total nonstructural carbohydrates in the C3 grasses. We conclude that C3 grasses will generally remain more nutritious than C3 grasses at elevated CO2 concentrations, having higher levels of protein, nonstructural carbohydrates, and water, but lower levels of fiber and toughness, and lower total carbohydrate:protein ratios than C4 grasses. [ABSTRACT FROM AUTHOR]

Summary 1. Mass-based and area-based rates of respiration, leaf nitrogen content, leaf total protein content, non-structural carbohydrates and leaf mass per unit area (LMA) all decreased with depth in the canopy of Nothofagus fusca (Hook. F.) Oerst. (Red beech) trees grown for 5 years at ambient (36 Pa) or elevated (66 Pa) CO2 partial pressures. 2. Elevated CO2 partial pressure had a strong effect on dark respiration, decreasing both mass-based and area-based rates at all canopy positions, but had little or no effect on leaf physical and biochemical properties. 3. Leaf sugars, starch, protein, N and LMA were all correlated with respiration rate, and are therefore strong predictors of area-based dark respiration rates. The y axis intercept of regressions of respiration rate on mean leaf N, protein, starch and LMA was lower for plants grown at elevated compared to ambient CO2 partial pressures because of the differential effect of growth at elevated CO2 partial pressure on leaf gas-exchange, chemical and physical characteristics. 4. The lower respiration rates for leaves from trees grown at elevated CO2 partial pressure resulted in a significant increase in the ratio of light-saturated net photosynthesis to respiration, increasing the potential carbon-use efficiency of these leaves. [ABSTRACT FROM AUTHOR]

Summary Immunosuppression in athletes involved in heavy training is undoubtedly multifactorial in origin. Training and competitive surroundings may increase the athlete's exposure to pathogens and provide optimal conditions for pathogen transmission. Heavy prolonged exertion is associated with numerous hormonal and biochemical changes, many of which potentially have detrimental effects on immune function. Furthermore, improper nutrition can compound the negative influence of heavy exertion on immunocompetence. An athlete exercising in a carbohydrate-depleted state experiences larger increases in circulating stress hormones and a greater perturbation of several immune function indices. The poor nutritional status of some athletes may predispose them to immunosuppression. For example, dietary deficiencies of protein and specific micronutrients have long been associated with immune dysfunction. Although it is impossible to counter the effects of all of the factors that contribute to exercise-induced immunosuppression, it has been shown to be possible to minimize the effects of many factors. Athletes can help themselves by eating a well-balanced diet that includes adequate protein and carbohydrate, sufficient to meet their energy requirements. This will ensure a more than adequate intake of trace elements without the need for special supplements. Consuming carbohydrate (but not glutamine or other amino acids) during exercise attenuates rises in stress hormones, such as cortisol, and appears to limit the degree of exercise-induced immunosuppression, at least for non-fatiguing bouts of exercise. Evidence that high doses of anti-oxidant vitamins can prevent exercise-induced immunosuppression is also lacking. [ABSTRACT FROM AUTHOR]

Significant mobilization of protein and carbohydrates in vegetative plant parts of wheat regularly occurs during grain filling. While this suggests a contribution of reserves to grain filling, the actual efficiency of mobilized assimilate conversion into grain mass (ME) is unknown. In the present study the contribution of pre-anthesis C (C fixed prior to anthesis) to grain filling in main stem ears of two spring wheat (Triticum aestivum L.) cultivars was determined by 13C/12C steady-state labelling. Mobilization of pre-anthesis C in vegetative plant parts between anthesis and maturity, and the contributions of water-soluble carbohydrates (WSC) and protein to pre-anthesis C mobilization were also assessed. Experiments were performed with two levels of N fertilizer supply in each of 2 years. Pre-anthesis reserves contributed 11–29% to the total mass of C in grains at maturity. Pre-anthesis C accumulation in grains was dependent on both the mass of pre-anthesis C mobilized in above-ground vegetative plant parts (r2 = 0·87) and ME (defined as g pre-anthesis C deposited in grains per g pre-anthesis C mobilized in above-ground vegetative plant parts; r2 = 0·40). ME varied between 0·48 and 0·75. The effects of years, N fertilizer treatments and cultivars on ME were all related to differences in the fractional contribution of WSC to pre-anthesis C mobilization. Multiple regression analysis indicated that C from mobilized pre-anthesis WSC may be used more efficiently in grain filling than C present in proteins at anthesis and mobilized during grain filling. Possible causes for variability of ME are discussed. [ABSTRACT FROM AUTHOR]

Senescence of isolated leaves of Hydrilla verticillata (L.f.) Royle was studied in both darkness and light (20 μmol m2 s1). Senescence in the dark followed a general pattern of deterioration, i.e., gradual loss of cellular macromolecules like chlorophyll, protein and RNA with a concomitant rise in α-amino nitrogen, protease activity and tissue permeability, in light, however, an accelerated loss of chlorophyll took place although protein loss and increase in protease activity were retarded. A higher level of α-amino nitrogen in leaves in the light than in darkness could be correlated with lower leaching of free amino acids in light. Light decreased tissue permeability, as evidenced by lower conductivity of the incubation medium. In the light, RNA in- creased over the initial level. Both soluble and insoluble carbohydrates declined in the dark. The decline of insoluble carbohydrate was retarded by light, whereas soluble carbohydrate showed an initial rise and then declined sharply in the light. [ABSTRACT FROM AUTHOR]

Seasonal fluctuations of carbohydrates and nitrogenous components in the roots of the noxious perennial leafy spurge (Euphorbia esula L.) are strongly associated with overwintering strategy. Amino acids and distinct soluble proteins accumulate during fall and remain at elevated levels throughout winter. The formation of carbohydrate reserves in roots was not significantly affected by decapitation or selective defoliation; however, maximum amino acid and soluble protein contents were markedly reduced. In particular, the accumulation pattern of a 26 kDa protein was altered. This protein may play a role in plant conditioning and regenerative potential. [ABSTRACT FROM AUTHOR]

Leafy spurge (Euphorbia esula L.), a serious perennial weed of temperature range and pasture lands, has continued to colonize despite various control strategies. The persistence of this species can be attributed in part to the presence of an extensive root system containing abundant organic reserves. These components, established towards the end of the growing season, are remobilized to support early spring growth. Carbohydrates comprise the bulk of reserve material with late fall increments in free sugars being associated with reductions in starch content. Nitrogenous components undergo significant seasonal fluxes, with free amino acids and soluble proteins reaching maxima during late fall. Asparagine, glutamic acid, serine, ornithine, proline, arginine and aspartic acid all contribute significantly to the storage of nitrogen. Changes in nitrate content are associated with the overwintering process. These observations are indicative of the role that nitrogen plays in the overwintering strategy and regenerative capacity of leafy spurge roots. [ABSTRACT FROM AUTHOR]

We determined the proximate chemical composition as well as the construction costs of leaves of 27 species, grown at ambient and at a twice-ambient partial pressure of atmospheric CO2. These species comprised wild and agricultural herbaceous plants as well as tree seedlings. Both average responses across species and the range in response were considered. Expressed on a total dry weight basis, the main change in chemical composition due to CO2 was the accumulation of total non-structural carbohydrates (TNC). To a lesser extent, decreases were found for organic N compounds and minerals. Hardlyany change was observed for total structural carbohydrates (cellulose plus hemicellulose), lignin and lipids. When expressed on a TNC-free basis decreases in organic N compounds and minerals were still present. On this basis, there was also an increase in the concentration of soluble phenolics. In terms of glucose required for biosynthesis, the increase in costs for one chemical compound -- TNC -- was balancedby a decrease in the costs for organic N compounds. Therefore, the construction costs, the total amount of glucose required to produce 1 g of leaf, were rather similar for the two CO2 treatments;on average a small decrease of 3% was found. This decrease was attributable to a decrease of up to 30% in the growth respiration coefficient, the total CO2 respired [mainly for NAD(P)H and ATP] in the process of constructing 1 g of biomass. The main reasons for this reduction were the decrease in organic N compounds and the increase in TNC. [ABSTRACT FROM AUTHOR]

Chicory (Cichorium intybus L.) and dandelion (Taraxacum officinale L.) are persistent weeds, the aerial portions of which do not survive in winter. However, subterranean tissues remain viable and facilitate the rapid resumption of growth in early spring. The source of nutrients for growth prior to the establishment of foliage is the roots. Carbohydrate and N reserves are accrued during late summer and autumn, respectively. Hydrolysis of fructans during late autumn occurs coincidentally with increments in sucrose, the latter providing a readily accessible C pool. Nitrate, free amino acids and soluble protein all play substantial roles in nitrogen storage. Asparagine is the predominant amino acid in the free pool during winter, followed by glutamine, ornithine, serine, aspartic acid and glutamic acid. Storage reserves remain at peak levels throughout winter and decline prior to the resumption of growth. The patterns observed here provide evidence that N is an important currency of storage metabolism and, thus, a framework has been provided for the examination of regulation of N storage in perennial weeds. [ABSTRACT FROM AUTHOR]