Carbohydrate Resources Research Articles

Production of Esters in Escherichia coli Using Citrate Synthase Variants.

Acetate esters comprise a wide range of products including fragrances and industrial solvents. Biosynthesis of esters offers a promising alternative to chemical synthesis because such routes use renewable carbohydrate resources and minimize the generation of waste. One biochemical method for ester formation relies on the ATF1 gene from Saccharomyces cerevisiae, which encodes alcohol-O-acyltransferase (AAT) which converts acetyl-CoA and an exogenously supplied alcohol into the ester. In this study, the formation of several acetate esters via AAT was examined in Escherichia coli chromosomally expressing citrate synthase variants, which create a metabolic bottleneck at acetyl-CoA. In shake flask cultures, variant strains generated more acetate esters than the strains expressing the wild-type citrate synthase. In a controlled bioreactor, E. coli GltA[A267T] generated 3.9 g propyl acetate in 13 h, corresponding to a yield of 0.155 g propyl acetate/g glucose, which is 18% greater than that obtained by the wild-type GltA control. These results demonstrate the ability of citrate synthase variants to redistribute carbon from central metabolism into acetyl-CoA-derived biochemicals.

Implications of cell wall immunocytochemical profiles on the structural and functional traits of root and stem galls induced by Eriosoma lanigerum on Malus domestica.

Alterations in cell wall composition imply in new structural and functional traits in gall developmental sites, even when the inducer is a sucking exophytophagous insect with strict feeding sites as the aphid associated to Malus domestica Borkh. This host plant is an economically important, fruit-bearing species, susceptible to gall induction by the sucking aphid Eriosoma lanigerum Hausmann, 1802. Herein, the immunocytochemical detection of arabinogalactan-proteins (AGPs), pectins, and hemicelluloses using monoclonal antibodies was performed in samples of non-galled roots and stems, and of root and stem galls on M. domestica. The dynamics of these cell wall components was discussed under the structural and functional traits of the galls proximal, median, and distal regions, according to the proximity of E. lanigerum colony feeding site. In the proximal region, the epitopes of AGPs and homogalacturonans (HGs) are related to cell growth and divisions, which result in the overproduction of parenchyma cells both in root and stem galls. In the proximal and median regions, the co-occurrence of HGs and arabinans in the cell walls of parenchyma and secondary tissues favors the nutrient flow and water-holding capacity, while the xylogalacturonans and hemicelluloses may function as additional carbohydrate resources to E. lanigerum. The immunocytochemical profile of the cell walls support the feeding activity of E. lanigerum mainly in the gall proximal region. The similarity of the cell wall components of the gall distal region and the non-galled portions, both in roots and stems, relates to the decrease of the cecidogenetic field the more distant the E. lanigerum colony is.

No evidence of carbon storage usage for seed production in 18 dipterocarp masting species in a tropical rain forest.

Most canopy species in lowland tropical rain forests in Southeast Asia, represented by Dipterocarpaceae, undergo mast reproduction synchronously at community level during a general flowering event. Such events occur at irregular intervals of 2-10years. Some species do not necessarily participate in every synchronous mast reproduction, however. This may be due to a lack of carbohydrate resources in the trees for masting. We tested the hypothesis that interspecific differences in the time required to store assimilates in trees for seed production are due to the frequency of masting and/or seed size in each species. We examined the relationship between reproductive frequency and the carbon accumulation period necessary for seed production, and between the seed size and the period, using radiocarbon analysis in 18 dipterocarp canopy species. The mean carbon accumulation period was 0.84years before seed maturation in all species studied. The carbon accumulation period did not have any significant correlation with reproductive frequency or seed size, both of which varied widely across the species studied. Our results show that for seed production, dipterocarp masting species do not use carbon assimilates stored for a period between the masting years, but instead use recent photosynthates produced primarily in a masting year, regardless of the masting interval or seed size of each species. These findings suggest that storage of carbohydrate resources is not a limiting factor in the masting of dipterocarps, and that accumulation and allocation of other resources is important as a precondition for participation in general flowering.

Non-starch polysaccharides from kidney beans: comprehensive insight into their extraction, structure and physicochemical and nutritional properties.

Kidney beans (Phaseolus vulgaris L.) are an important legume source of carbohydrates, proteins, and bioactive molecules and thus have attracted increasing attention for their high nutritional value and sustainability. Non-starch polysaccharides (NSPs) in kidney beans account for a high proportion and have a significant impact on their biological functions. Herein, we critically update the information on kidney bean varieties and factors that influence the physicochemical properties of carbohydrates, proteins, and phenolic compounds. Furthermore, their extraction methods, structural characteristics, and health regulatory effects, such as the regulation of intestinal health and anti-obesity and anti-diabetic effects, are also summarized. This review will provide suggestions for further investigation of the structure of kidney bean NSPs, their relationships with biological functions, and the development of NSPs as novel plant carbohydrate resources.

A microscopic scenario on recovery mechanisms under waterlogging and submergence stress in rice.

Adaptive traits in rice responding to flooding, a compound stress, are associated with morpho-anatomical and physiological changes which are regulated at the genetic level. Therefore, understanding submergence stress tolerance in rice will help development of adapted cultivars that can help mitigate agricultural losses. Rice is an important dietary component of daily human consumption and is cultivated as a staple crop worldwide. Flooding is a compound stress which imposes significant financial losses to farmers. Flood-affected rainfed rice ecosystems led to the development of various adaptive traits in different cultivars for their optimal growth and survival. Some cultivars can tolerate hypoxia by temporarily arresting elongation and conserving their energy sources, which they utilize to regrow after the stress conditions subside. However, few other cultivars rapidly elongate to escape hypoxia using carbohydrate resources. These contrasting characters are regulated at the genetic level through different quantitative trait loci that contain ERF transcription factors (TFs), Submergence and Snorkels. TFs can simultaneously activate the transcription of various genes involved in stress and development responses. These TFs are of prime importance because the introgressed and near-isogenic lines showed promising results with increased submergence tolerance without affecting yield or quality. However, the entire landscape of submergence tolerance is not entirely depicted, and further exploration in the field is necessary to understand the mechanism in rice completely. Therefore, this review will highlight the significant adaptive traits observed in flooded rice varieties and how they are regulated mechanistically.

Effect of raw material structural composition on the fermentation process of ethanol production

Ethanol is becoming the important renewable energy sources in the world which produces from carbohydrate resources. The raw material selection is the important procedure for real industrial production. The effect of biomass structural composition in feedstock on ethanol production is therefore needed to explore for feedstock selection. According to the previous research studies, the fermentation process includes pre-treatment and fermentation of sugar to ethanol. This study focuses on the simulation of raw material variation in ethanol production especially the structural composition of carbohydrate that contains three main components, cellulose, xylan, and lignin, in the fermentation section. The simulation model is validated by the data of previous study information with small deviation. The mixture design method is used for result interpretation and analysis. From the design of experiment, there are 14 scenarios and the selected response parameter is the mass fraction of ethanol in outlet stream of fermentation section. From the results, the maximum mass fraction of ethanol in outlet stream is in the scenario which has a large amount of cellulose and xylan fractions. This is because the conversion of reaction in the fermentation reactor mostly consumes cellulose and xylan to produce glucose and xylose, respectively, and converts them into ethanol product. From the overall result of this study, the important of raw material selection in ethanol production is illustrated.

Hierarchically bread-derived carbon foam decorated with defect engineering in reduced graphene oxide/carbon particle nanocomposites as electrode materials for solid-state supercapacitors

The rational design of defective sites and atomic structure of electrode materials for energy storage devices still remains a challenge. Herein, hierarchically activated carbon foam (ACF) from bread has been developed. The density functional theory (DFT) calculation reveals that oxygen defects can form in the reduced graphene oxide/carbon particle (rGO/CP) derived from graphene oxide frameworks (GOFs) by adding the reducing agent. The synergistic effects of the internal porous architecture of ACF and external interface coupling formed by the defect-rich rGO/CP nanocomposites can provide more electrons to adsorb -OH anions resulting in superior electrochemical energy storage performance. Therefore, the ACF-rGO/large-scale carbon particle (ACF-rGO/LCP) electrodes show ultrahigh specific capacitance (521 F g−1) at a current density of 0.5 A g−1 and outstanding cycling stability with capacitance retention of 96.4 % over 12,000 cycles. Furthermore, the assembled binder-free supercapacitor using KOH/polyvinyl alcohol (PVA) as a gel electrolyte, displays a high energy density of 27.5 W h kg−1 with a power density of 472 W kg−1, and a capacitance retention of 95.2 % after 12,000 cycles. This work provides a novel pathway to prepare high-performance supercapacitors via the treatment of food waste and the recycling of carbohydrate resources.

Coral holobiont research needs spatial analyses at the microbial scale.

Coral holobiont research needs spatial analyses at the microbial scale.

The starch-sugar interconversion mechanism during bulb development of Cardiocrinum giganteum (Wall.) Makino revealed by transcriptome and metabolite analysis

Cardiocrinum giganteum bulbs are rich in starch and natural compounds that benefit health. To better utilize the bulb starch of C. giganteum as an edible resource, understanding of the kinetics of starch and sucrose accumulation as well as the involved metabolic pathways in different developmental stages of the bulbs are required. In this study, we compared the dynamic changes in the transcriptomes and metabolomes of the bulbs over different developmental stages. A total of 43,692 differentially expressed genes and 508 metabolites were identified, which were clustered into nine co-expression clusters based on biological functions. Starch and sucrose metabolic pathways were identified at both the transcriptome and metabolome levels, revealing that activating the pathways of starch synthesis as well as sucrose synthesis and hydrolysis could be main conversion modes in starch-sugar interconversion. The data showed that the starch synthesis genes GBSS, SS3, GBE and ISA were expressed to highest levels at the stage of three-four years of C. giganteum development (c3y-c4y), concomitantly with the highest starch contents in this period. This revealed that the starch from the developing bulbs is optimally harvested at this stage. Meanwhile, sucrose synthesis genes were active and sucrose metabolites were maintained in balance during this stage, providing carbohydrate resources for starch biosynthesis. In the four-five year stage of development (c4y-c5y), the contents of sucrose metabolites increased, starch synthesis slowed down and sucrose hydrolysis genes were activated. Moreover, qRT-PCR analysis showed that the temporal expression patterns of starch and sucrose biosynthesis genes were largely consistent with the RNA-seq results. Taken together, these findings provide important information on the regulatory mechanisms of starch-sugar interconversion during C. giganteum bulb development.

Structural heterogeneity of wildflower strips enhances fructose feeding in parasitoids

The use of wildflower strips to provide carbohydrate resource for parasitoids and enhance pest regulation is widely recommended in agriculture. However, how the management of wildflower strips affects resource availability and utilisation by parasitoids has never been studied. Using orange orchards as a model system, three experimental alleyway management treatments were investigated: a control treatment where naturally occurring vegetation in the alleyways between rows of trees was managed under standard farm practice; a standard management wildflower treatment in which sown wildflower strips in alleyways were managed by cutting once a year; and an active management wildflower treatment, in which the wildflower strips in alleyways was managed by cutting three times a year. Wildflower strips under standard management prevented the seasonal decline of nectar, supporting fructose feeding in parasitoids across all three seasons. The abundance of floral and hemipteran honeydew carbohydrate resources in the orchard alleyways and citrus canopy was consistently greater with the standard management treatment than the control or the active management treatments. In turn, this treatment was associated with twice the abundance of primary parasitoids than with the control and active management treatments in both summer and autumn. In addition, in autumn, parasitoids were more likely to have recently fed on carbohydrate in the standard management treatment than in the other two alleyway treatments. Finally, greater carbohydrate feeding in parasitoids was associated with increased structural heterogeneity of vegetation within the orchard alleyways. This study demonstrates that the nutritional status of parasitoids in a perennial cropping system can be improved using wildflower strips, which could enhance pest regulation, and emphasises the importance of studying the management of wildflower strips when targeting specific resource requirements.

Carbohydrates complement high-protein diets to maximize the growth of an actively hunting predator.

In nature, food is often variable in composition and availability. As a consequence, predators may need to seek non‐prey food sources. Some predators are known to feed on nectar when food is limited. Nectar and other carbohydrate resources could also be beneficial when prey are more abundant if it helps predators balance protein‐biased diets. We tested if an actively hunting predator, the jumping spider, Phidippus audax, benefited from liquid carbohydrates when prey were not limited. We also tested if the benefit of carbohydrates varied with the nutrient content of prey (i.e., from protein to lipid biased). Spiders were reared on one of six live prey, Drosophila melanogaster, treatments that ranged from high protein to high lipid. Half of the spiders were given access to a 20% sucrose solution. After 2 months, we measured spider mass, cephalothorax width, instar duration, percent body fat, survival, and estimated number of prey eaten. Spiders reared on high‐protein diets with carbohydrates were larger and heavier than spiders on other treatments. Access to carbohydrates also increased percent body fat and survival across prey treatments. Our results suggest that carbohydrates may be a valuable component of spider diets, especially when prey have high protein and low lipid content as is commonly observed in prey in the field. Our results highlight the importance of diet balancing for predators, and that liquid carbohydrates can be an important nutrient to supplement a diet of prey rather than just being an energy supplement during periods of starvation.

Provision of carbohydrate resources to support Apanteles polychrosidis, to increase parasitism of Caloptilia fraxinella in horticultural ash trees

The provision of nutritional resources for beneficial insects that support pest control, such as parasitoid wasps, is one tactic in conservation biological control. This tactic could be an important element for the development of a biological control program to help control the ash leaf-cone roller, Caloptilia fraxinella Ely (Lepidoptera: Gracillariidae), an introduced pest of horticultural ash trees (Fraxinus) in Canadian Prairie cities, including Edmonton, AB, Canada. In the current study, we test the efficacy of carbohydrate food provision to support parasitism of C. fraxinella by its primary parasitoid, Apanteles polychrosidis Viereck (Hymenoptera: Braconidae). Laboratory experiments compared the longevity, parasitism rate and offspring fitness of wasps fed sucrose solutions at one of two concentrations (10 and 25% v/v) or flowers of buckwheat, Fagopyrum esculentum (Polygonaceae). Fed wasps lived longer than wasps with access to water only. Mated, but not unmated, males and females lived longer when fed 25% than 10% sucrose. Female A. polychrosidis had similar longevity when fed 25% sucrose or buckwheat flowers. Egg load did not change with sucrose provision. Adult longevity of fed unmated female A. polychrosidis was negatively correlated with egg load. Female A. polychrosidis fed 25% sucrose produced offspring with a slightly female-biased sex ratio and higher fecundity than offspring from female A. polychrosidis fed the 10% sucrose solution.

Floral and Bird Excreta Semiochemicals Attract Western Carpenter Ants

Ant colonies have vast and diverse nutritional needs but forager ants have limited mobility to meet these needs. Forager ants would accrue significant energy savings if they were able to sense and orient toward odor plumes of both carbohydrate and protein food sources. Moreover, if worker ants, like other flightless insects, had reduced olfactory acuity, they would not recognize the specific odor signatures of diverse carbohydrate and protein sources, but they may be able to orient toward those odorants that are shared between (macronutrient) food sources. Using the Western carpenter ant, Camponotus modoc, as a model species, we tested the hypotheses that (1) food sources rich in carbohydrates (aphid honeydew, floral nectar) and rich in proteins (bird excreta, house mouse carrion, cow liver infested or not with fly maggots) all prompt long-distance, anemotactic attraction of worker ants, and (2) attraction of ants to plant inflorescences (fireweed, Chamaenerion angustifolium; thimbleberry, Rubus parviflorus; and hardhack, Spiraea douglasii) is mediated by shared floral odorants. In moving-air Y-tube olfactometer bioassays, ants were attracted to two of four carbohydrate sources (thimbleberry and fireweed), and one of four protein sources (bird excreta). Headspace volatiles of these three attractive sources were analyzed by gas chromatography-mass spectrometry, and synthetic odor blends of thimbleberry (7 components), fireweed (23 components), and bird excreta (38 components) were prepared. In Y-tube olfactometer bioassays, synthetic blends of thimbleberry and fireweed but not of bird excreta attracted ants, indicating that only the two floral blends contained all essential attractants. A blend of components shared between thimbleberry and fireweed was not attractive to ants. Our data support the conclusion that C. modoc worker ants can sense and orient toward both carbohydrate and protein food sources. As ants were selective in their responses to carbohydrate and protein resources, it seems that they can discern between specific food odor profiles and that they have good, rather than poor, olfactory acuity.

Food deprivation alters reproductive performance of biocontrol agent Hadronotus pennsylvanicus

Diet can influence parasitoid reproductive performance, and therefore, the efficacy of biocontrol programs. We evaluated the influence of food deprivation on the reproductive fitness and behavior of the egg parasitoid Hadronotus pennsylvanicus (Hymenoptera: Scelionidae), a prospective biocontrol agent for Leptoglossus zonatus (Heteroptera: Coreidae). Newly emerged female parasitoids were mated and provided host eggs every other day while being provisioned with various honey diet regimes or a consistent supply of water. When given frequent access to a honey diet, female parasitoids lived significantly longer and parasitized more host eggs compared to the water-fed controls. Once depleted of mature eggs, females with frequent access to honey also contributed to greater non-reproductive host mortality. Furthermore, behavioral assays demonstrated that water-fed females spent less time interacting with host eggs and tended to more frequently divert from oviposition behavior. While there was no difference in the average duration until first oviposition between individuals assigned to different diet treatments, increased frequency of honey feeding was associated with more frequent and longer duration of oviposition. The positive effect of honey feeding on the reproductive performance of biocontrol agent H. pennsylvanicus suggests that performance of this parasitoid under field conditions could be enhanced through the provision of similar carbohydrate resources, such as flowering summer cover crops.

Review] Fundamental Research on Efficient Utilization of Regional Carbohydrate Resources:

Review] Fundamental Research on Efficient Utilization of Regional Carbohydrate Resources:

Specialized compounds across ontogeny in the seagrass Posidonia oceanica

Differences in phenolic composition across different ontogenic stages can be crucial in determining the interaction outcomes between plants and their surrounding biotic environment. In seagrasses, specific phenolic compounds have rarely been analyzed and remain unexplored in ontogenic stages other than non-reproductive adults. Furthermore, it is generally accepted that plants would prioritize defense (e.g., through increased phenolic content) on tissues or stages that are critical for plant fitness but how this affects nutritional quality or plant resources has been scarcely explored. We analyzed how phenolic composition, N and C content and carbohydrate resources varied among different life stages (i.e. old and young leaves of reproductive and non-reproductive plants, and leaves of seedlings) in the seagrass Posidonia oceanica. We identified five phenolic compounds, whose structures were established as hydroxycinnamate esters of tartaric acid. Also, our results show that in all examined ontogenic stages phenolic compounds have the same qualitative composition but inflorescences exhibit higher contents than vegetative tissues. We did not find a reduction in stored resources in reproductive plants, pointing to some kind of compensatory mechanism in the production or storage of resources. In contrast, seedlings seemed to have less phenolic compounds than reproductive plants, perhaps due to limited resources available to allocate to phenolic production. Our results demonstrate how different ontogenic stages change their investment in specialized phenolic compounds prioritizing different functions according to the needs and limitations of that stage.

Invasive ant establishment, spread, and management with changing climate.

Ant invasions and climate change both pose globally widespread threats to the environment and economy. I highlight our current knowledge of how climate change will affect invasive ant distributions, population growth, spread, impact, and invasive ant management. Invasive ants often have traits that enable rapid colony growth in a range of habitats. Consequently, many invasive ant species will continue to have large global distributions as environmental conditions change. Distributions and impacts at community scales will depend on how resident ant communities respond to local abiotic conditions as well as availability of plant-based carbohydrate resources. Though target species may change under an altered climate, invasive ant impacts are unlikely to diminish, and novel control methods will be necessary.

All sugars ain't sweet: selection of particular mono-, di- and trisaccharides by western carpenter ants and European fire ants.

Ants select sustained carbohydrate resources, such as aphid honeydew, based on many factors including sugar type, volume and concentration. We tested the hypotheses (H1–H3) that western carpenter ants, Camponotus modoc, seek honeydew excretions from Cinara splendens aphids based solely on the presence of sugar constituents (H1), prefer sugar solutions containing aphid-specific sugars (H2) and preferentially seek sugar solutions with higher sugar content (H3). We further tested the hypothesis (H4) that workers of both Ca. modoc and European fire ants, Myrmica rubra, selectively consume particular mono-, di- and trisaccharides. In choice bioassays with entire ant colonies, sugar constituents in honeydew (but not aphid-specific sugar) as well as sugar concentration affected foraging decisions by Ca. modoc. Both Ca. modoc and M. rubra foragers preferred fructose to other monosaccharides (xylose, glucose) and sucrose to other disaccharides (maltose, melibiose, trehalose). Conversely, when offered a choice between the aphid-specific trisaccharides raffinose and melezitose, Ca. modoc and M. rubra favoured raffinose and melezitose, respectively. Testing the favourite mono-, di- and trisaccharide head-to-head, both ant species favoured sucrose. While both sugar type and sugar concentration are the ultimate cause for consumption by foraging ants, strong recruitment of nest-mates to superior sources is probably the major proximate cause.

Managing Crop Load in European Pear (Pyrus communis L.)—A Review

Reducing levels of fruit set is often desirable in many European pear (Pyrus communis L.) cultivars. With a negative linear relationship between crop load and fruit size, crop load management early in the season minimises wastage of tree carbohydrate resources and provides maximum benefits in terms of fruit size and quality. There are several tools available for managing crop load including hand thinning, chemical thinning, photosynthetic inhibition through shading or application of chemicals, mechanical thinning and pruning. While hand thinning is the most accurate method of reducing excessive crop loads, there are some major drawbacks. With awareness that the early thinning offered by chemical thinning provides distinct advantages with regard to fruit size and other quality parameters, chemical thinning is gaining increasing acceptance in pear production. Some chemicals are used worldwide for thinning, but there are differences between countries and growing regions on recommended application timing and concentrations. The risks involved in chemical thinning can be mitigated by use of a structured approach, using a sequential spray program with both bloom and post-bloom thinners. Knowledge of conditions that impact the carbon balance of the tree and the ability to make use of carbon-deficit conditions are likely to improve the predictability of chemical thinning. Mechanical thinning has potential as a thinning tool, with advantages over chemical thinning in that it is environmentally friendly, can be used in organic production and is not weather dependent. Although artificial bud extinction has not been trialled on pears to date, it has been shown to be economically viable in apple. As it is a precision crop load management method that minimises tree resource wastage, it should be given serious consideration. As growers require large annual yields of high-quality fruit, the aim of this review was to examine current and potential crop load management methods for European pear cultivars and provide a portfolio of available options that can be integrated into a systematic approach for managing crop load.

Pemanfaatan Ampas Sagu sebagai Mulsa Organik dalam Peningkatkan Pertumbuhan Tanaman Sagu (Metroxylon sagu Rottb.) Di Lapang

Sago palm need to be cultivated intensively for increasing carbohydrate resources to anticipate the deficiency of energy sources of the world. This study aims to measure the influences of sago dregs to the sag palm growth in the field. The experimental method used in this works was Randomized Block Design that consisting of five treatments sago dregs weights in the russet stages of sago palm. The composition of the treatment is follows: without sago dregs (P0), 5 kg sago dregs tree-1 (P1), 10 kg of sago dregs tree-1 (P2), 15 kg sago dregs tree-1 (P3), 20 kg sago dregs tree-1 (P4). The results showed that sago dregs had a significant effect of the spear leaves growth, but not significantly effect of the plant height growth, number of leaflets growth, and number of leaflets. Utilization of 10 kg sago dregs tree-1 as mulch was calculated influence of the spear leaf growth and utilization of 20 kg sago dregs as mulch inhibitory of sago palm growth.