Sugar Composition Research Articles

Generation of Null Mutants to Elucidate the Role of Bacterial Glycosyltransferases in Bacterial Motility.

The study of glycosylation in prokaryotes is a rapidly growing area. Bacteria harbor different glycosylated structures on their surface whose glycans constitute a strain-specific barcode. The associated glycans show higher diversity in sugar composition and structure than those of eukaryotes and are important in bacterial-host recognition processes and interaction with the environment. In pathogenic bacteria, glycoproteins have been involved in different stages of the infectious process, and glycan modifications can interfere with specific functions of glycoproteins. However, despite the advances made in the understanding of glycan composition, structure, and biosynthesis pathways, understanding of the role of glycoproteins in pathogenicity or interaction with the environment remains very limited. Furthermore, in some bacteria, the enzymes required for protein glycosylation are shared with other polysaccharide biosynthetic pathways, such as lipopolysaccharide and capsule biosynthetic pathways. The functional importance of glycosylation has been elucidated in several bacteria through mutation of specific genes thought to be involved in the glycosylation process and the study of its impact on the expression of the target glycoprotein and the modifying glycan. Mesophilic Aeromonas have a single and O-glycosylated polar flagellum. Flagellar glycans show diversity in carbohydrate composition and chain length between Aeromonas strains. However, all strains analyzed to date show a pseudaminic acid derivative as the linking sugar that modifies serine or threonine residues. The pseudaminic acid derivative is required for polar flagella assembly, and its loss has an impact on adhesion, biofilm formation, and colonization. The protocol detailed in this article describes how the construction of null mutants can be used to understand the involvement of genes or genome regions containing putative glycosyltransferases in the biosynthesis of a flagellar glycan. This includes the potential to understand the function of the glycosyltransferases involved and the role of the glycan. This will be achieved by comparing the glycan deficient mutant to the wild-type strain.

Structural Characterization of Mannoglucan Isolated from Ophiocordyceps sobolifera and Its Antioxidant Activities.

A novel polysaccharide structure (PS-T80) was collected from Ophiocordyceps sobolifera biomass and characterized via a combination of chemical and spectral analyses. Employing high-performance gel permeation chromatography (HPGPC), the average molecular weight is proven to be 7.4 × 104 Da. Furthermore, a sugar composition analysis of the obtained polysaccharide suggests two main sugars, β-d-glucose and α-d-mannose, at a molar ratio of 2:1, respectively, in the backbone. The structure analysis unveils that PS-T80 is a mannoglucan, possessing the repeating unit of [→3)-β-d-Glcp-(1 → 3)-α-d-Manp-(1 → 3)-β-d-Glcp-(1→]n. Such a configuration could be considered a novel polysaccharide. Impressively, in vitro antioxidant tests revealed that PS-T80 has a promising antioxidant activity. These results demonstrate that the obtained PS is a potential bioactive material for biomedical applications.

Toward bioeconomy of a multipurpose cereal: Cell wall chemistry of Sorghum is largely buffered against stem sugar content

AbstractBackground and ObjectivesSorghum (Sorghum bicolor L. Moench) is a multipurpose crop with high potential for the bioeconomy. Ten sweet, grain and dual‐purpose sorghum genotypes were compared with respect to sugar‐related traits and cell wall composition.FindingsThe dual‐purpose hybrids Ganymed, Zerberus, and Tarzan performed better with respect to plant height, cane weight, and juice volume, but the sweet genotype KIT1 produced the highest sugar concentration (°Brix) in the stem. Analytical sugar data demonstrate genotypic differences in terms of sugar composition and concentrations, with sucrose being dominant. The monosaccharide composition of the stem cell wall polysaccharides showed surprisingly little genotypic variability. Variations in contents of lignin and cell wall‐bound hydroxycinnamate monomers were moderate.ConclusionsSweet, grain and dual‐purpose sorghum genotypes differ widely in terms of sugar‐related morphological parameters but are comparable with respect to their cell wall chemistry.Significance and NoveltyThe use of sorghum as a bioeconomy crop has mainly focused on the extraction of sugar for bioethanol production. However, besides cell wall polymers, the potential usage of hydroxycinnamates as platform molecules for the chemical industry may improve the valorization of the residues after sugar extraction. This application appears to be fairly independent of genotype, further increasing the potential of sorghum for the bioeconomy.

Level of Students ‘Functional Abilities as a Parameter for Determining Differences in Triglyceride, Cholesterol, Blood Sugar and Body Composition in Students

The aim of the study was to determine the differences in the level of fat, sugar and body structure based on the level of functional abilities. The sample of respondents are students of the University of Bihać who also completed the shuttle run test (BEEPT). T-test for independent samples revealed the existence of statistically significant differences between the arithmetic means of the two groups of subjects for (AMAS, p = 0 .011), (BMI p = 0 .000), (FAT%, p = 0.000), (FMKG p) = 0.000). A statistically significant difference was also found in the variable triglycerides (TRIGL p = 0.019), while in the other variables no statistically significant difference was found in the two groups of subjects in favor of subjects who had better results in functional abilities. The coefficient of discriminant canonical correlation is (0.512), as is Wilks lambda, (0.738), which indicates very high discrimination between groups (sig. 000). The greatest contribution to the formation of the discriminatory function was given by the variables FMKG - .801, FATPR -.760, BMI - .707, AMAS - .390, TRIGL - .358, HOLE - .235. The centroids of the groups show a large distance between the results of the groups because they are located at both ends of the coordinate system. The first group consists of positive results of a total of 7 variables, which means that the respondents of the first group had significantly better results in these variables. Based on the results, it can be concluded that the increase in cholesterol triglycerides and some parameters of body structure affected the level of health status as well as body composition in students.

Phytochemical and Nutritional Profile Composition in Fruits of Different Sweet Chestnut (Castanea sativa Mill.) Cultivars Grown in Romania

Chestnut (Castanea sativa Mill.), a valuable fruit crop, is cultivated in small areas in Romania, mostly in the west, where the moderate continental climate has a slight Mediterranean influence. This work aims to investigate the bioactive characteristics (total polyphenols, total flavonoids and antioxidant activity), individual polyphenolic composition, phytochemical and nutritional HRMS screening profiles, sugar and mineral composition of six sweet chestnut cultivars, namely ‘Marsol’, ‘Maraval’, ‘Bournette’, ‘Précoce Migoule’ and ‘Marissard’ grown at Fruit Growing Research—Extension Station (SCDP) Vâlcea, in Northern Oltenia, Romania. Fruit samples were collected in two consecutive years, in order to study the impact of genetic variability between cultivars and the influence of the different climatic conditions corresponding to different cultivation years. Principal Component Analysis (PCA) and Hierarchical Cluster Analysis (HCA) allow the discrimination between the sweet chestnut fruits harvested in different years and different sweet chestnut cultivars. Analytical investigations revealed that sweet chestnut cultivars grown in Romania show similar bioactive, phytochemical and nutritional composition to cultivars grown in the large European chestnut-producing countries, indicating the high adaptation potential of the chestnut in the temperate continental zone with small Mediterranean influences characteristic of the southwestern area of Romania.

A microwave-based extraction method for the determination of sugar and polyols: Application to the characterization of regular and peaberry coffees

The brewing properties of coffee products are defined by the chemical composition in the bean, including sugars and polyols. Some factors, such as coffee species and roasting, may affect the level of these compounds in the bean. A new analytical microwave-assisted extraction (MAE) method has been developed to extract sugars and polyols from the coffee bean. The studied extraction conditions for the MAE were temperature (30–80 °C), solvent composition (0–50% ethanol in water), and solvent-to-sample ratio (10:1–30:1 mL solvent per g sample). A Box-Behnken design was applied to study the effect of extraction variables, and subsequently, the influential variables were optimized by response surface methodology (RSM). In addition to the main effect of the solvent-to-sample ratio, all quadratic effects significantly influenced ( p < 0.05) the recovery of sugars and polyols from the coffee beans. RSM suggested the optimized MAE conditions: temperature 52 °C, ethanol concentration in water 18.5%, and solvent-to-sample ratio 17:1. Under the optimum condition, a kinetics study confirmed that 15 min showed high precision and accuracy of the developed method. Ultimately, a real sample application of the developed MAE revealed that the new method successfully described the composition of sugars and polyols in regular and peaberry coffee beans. Additionally, the method also effectively characterized the green and roasted Arabica and Robusta coffee beans.

Composition and yield of non-cellulosic and cellulosic sugars in soluble and particulate fractions during consolidated bioprocessing of poplar biomass by Clostridium thermocellum

BackgroundTerrestrial plant biomass is the primary renewable carbon feedstock for enabling transition to a sustainable bioeconomy. Consolidated bioprocessing (CBP) by the cellulolytic thermophile Clostridium thermocellum offers a single step microbial platform for production of biofuels and biochemicals via simultaneous solubilization of carbohydrates from lignocellulosic biomass and conversion to products. Here, solubilization of cell wall cellulosic, hemicellulosic, and pectic polysaccharides in the liquor and solid residues generated during CBP of poplar biomass by C. thermocellum was analyzed.ResultsThe total amount of biomass solubilized in the C. thermocellum DSM1313 fermentation platform was 5.8, 10.3, and 13.7% of milled non-pretreated poplar after 24, 48, and 120 h, respectively. These results demonstrate solubilization of 24% cellulose and 17% non-cellulosic sugars after 120 h, consistent with prior reports. The net solubilization of non-cellulosic sugars by C. thermocellum (after correcting for the uninoculated control fermentations) was 13 to 36% of arabinose (Ara), xylose (Xyl), galactose (Gal), mannose (Man), and glucose (Glc); and 15% and 3% of fucose and glucuronic acid, respectively. No rhamnose was solubilized and 71% of the galacturonic acid (GalA) was solubilized. These results indicate that C. thermocellum may be selective for the types and/or rate of solubilization of the non-cellulosic wall polymers. Xyl, Man, and Glc were found to accumulate in the fermentation liquor at levels greater than in uninoculated control fermentations, whereas Ara and Gal did not accumulate, suggesting that C. thermocellum solubilizes both hemicelluloses and pectins but utilizes them differently. After five days of fermentation, the relative amount of Rha in the solid residues increased 21% indicating that the Rha-containing polymer rhamnogalacturonan I (RG-I) was not effectively solubilized by C. thermocellum CBP, a result confirmed by immunoassays. Comparison of the sugars in the liquor versus solid residue showed that C. thermocellum solubilized hemicellulosic xylan and mannan, but did not fully utilize them, solubilized and appeared to utilize pectic homogalacturonan, and did not solubilize RG-I.ConclusionsThe significant relative increase in RG-I in poplar solid residues following CBP indicates that C. thermocellum did not solubilize RG-I. These results support the hypothesis that this pectic glycan may be one barrier for efficient solubilization of poplar by C. thermocellum.

Chemical characteristics of heterogeneous lignocellulosic microfines prepared using the glycol ether-organosolv process: dissolution properties in an NaOH–urea aqueous solution

Abstract In this study, heterogeneous lignocellulosic microfines (LCMFs) with different physicochemical properties were prepared from softwood by adjusting the reaction conditions of a glycol ether-organosolv process. The dissolution properties of heterogeneous LCMFs in an NaOH–urea aqueous solution were evaluated. As the reaction time increased, the yield and residual lignin content decreased. As the amount of chemical solution used to prepare LCMFs increased, more lignin than carbohydrates were removed, but the degree of polymerization (DP) was maintained. Finally, LCMFs with different residual lignin content, DP, and crystallinity were prepared via the glycol ether-organosolv process under various conditions. It was observed that lower the lignin content of heterogeneous LCMFs, higher were their solubilities in the NaOH–urea solution. The effect of DP on solubility was not significant; however, the hemicellulose content of LCMFs had a greater effect on their solubilities in the NaOH–urea aqueous solution than the sugar composition of hemicellulose. The chemical properties of lignin present in LCMFs had no significant effect on their solubilities in the NaOH–urea aqueous solution.

Nutritional and Functional Potential of Carob Syrup Versus Date and Maple Syrups.

SUMMARYResearch backgroundThe carob tree (Ceratonia siliqua L.) is grown primarily for its seeds that are utilized in the production of the highly prized locust bean gum. The material left after the separation of seeds from the pods is utilized in the production of a range of traditional products including carob syrup, usually in cottage-type industries. The international market penetration of carob syrups is rather limited and, accordingly, scant information exists on their composition and phytochemical properties compared to mainstream syrups. The present study aims to determine key chemical parameters, phenolic profiles and antioxidant properties of carob syrups and benchmark these against those of date and maple syrups.Experimental approachCarob syrups were prepared from 19 accessions of the carob, under laboratory conditions, by a similar procedure to those practiced by small-scale producers. The pH, browning index, the content of proteins, minerals, hydroxymethylfurfural, sugar composition, total phenols, antioxidant capacity and phenolic profiles of the produced syrups along with branded samples of date and maple syrups were analyzed.Results and conclusionsThe pH and sugar composition of the carob syrups were comparable to those of date and maple syrups. In general, the carob syrups contained more proteins, minerals, phenolic acids, flavonoids and total phenols, and exhibited higher antioxidant capacity than the date and maple syrups. The carob syrups exhibited excessive browning and contained more, or comparable content of hydroxymethylfurfural, than the date and maple syrups. The data indicate that carob syrups provide more nutrients and possess superior antioxidant potential to date and maple syrups. The high contents of the carcinogenic hydroxymethylfurfural of the carob syrups warrant milder heating regimens in the concentration step during production.Novelty and scientific contributionIn contrast to studies based on commercial and/or homemade syrups, this work utilized a relatively large number of laboratory-prepared samples for creating a robust database for carob syrup. The results indicated that carob syrups possess superior health promotion and disease prevention effects than the widely traded date and maple syrups. In addition to their potential positive contribution to public health, carob syrups have been shown to be promising candidates for bolstering the economic returns of farmers in carob-producing countries.

Carrageenan of Red Algae Eucheuma gelatinae: Extraction, Antioxidant Activity, Rheology Characteristics, and Physicochemistry Characterization.

Carrageenan is an anionic sulfated polysaccharide that accounts for a high content of red seaweed Eucheuma gelatinae. This paper focused on the extraction, optimization, and evaluation of antioxidant activity, rheology characteristics, and physic-chemistry characterization of β-carrageenan from Eucheuma gelatinae. The extraction and the optimization of β-carrageenan were by the maceration-stirred method and the experimental model of Box-Behken. Antioxidant activity was evaluated to be the total antioxidant activity and reducing power activity. The rheology characteristics of carrageenan were measured to be gel strength and viscosity. Physic-chemistry characterization was determined, including the molecular weight, sugar composition, function groups, and crystal structure, through GCP, GC-FID, FTIR, and XRD. The results showed that carrageenan possessed antioxidant activity, had intrinsic viscosity and gel strength, corresponding to 263.02 cps and 487.5 g/cm2, respectively. Antioxidant carrageenan is composed of rhamnose, mannose, glucose, fucose, and xylose, with two molecular weight fractions of 2.635 × 106 and 2.58 × 106 g/mol, respectively. Antioxidant carrageenan did not exist in the crystal. The optimization condition of antioxidant carrageenan extraction was done at 82.35 °C for 115.35 min with a solvent-to-algae ratio of 36.42 (v/w). At the optimization condition, the extraction efficiency of carrageenan was predicted to be 87.56 ± 5.61 (%), the total antioxidant activity and reducing power activity were predicted to 71.95 ± 5.32 (mg ascorbic acid equivalent/g DW) and 89.84 ± 5.84 (mg FeSO4 equivalent/g DW), respectively. Purity carrageenan content got the highest value at 42.68 ± 2.37 (%, DW). Antioxidant carrageenan from Eucheuma gelatinae is of potential use in food and pharmaceuticals.

Changes in neutral sugar composition, molar mass and molar mass distribution, and solid-state structures of birch and Douglas fir by repeated sodium chlorite delignification

Changes in neutral sugar composition, molar mass and molar mass distribution, and solid-state structures of birch and Douglas fir by repeated sodium chlorite delignification

Abundance of Major Cell Wall Components in Natural Variants and Pedigrees of Populus trichocarpa.

The rapid analysis of biopolymers including lignin and sugars in lignocellulosic biomass cell walls is essential for the analysis of the large sample populations needed for identifying heritable genetic variation in biomass feedstocks for biofuels and bioproducts. In this study, we reported the analysis of cell wall lignin content, syringyl/guaiacyl (S/G) ratio, as well as glucose and xylose content by high-throughput pyrolysis-molecular beam mass spectrometry (py-MBMS) for >3,600 samples derived from hundreds of accessions of Populus trichocarpa from natural populations, as well as pedigrees constructed from 14 parents (7 × 7). Partial Least Squares (PLS) regression models were built from the samples of known sugar composition previously determined by hydrolysis followed by nuclear magnetic resonance (NMR) analysis. Key spectral features positively correlated with glucose content consisted of m/z 126, 98, and 69, among others, deriving from pyrolyzates such as hydroxymethylfurfural, maltol, and other sugar-derived species. Xylose content positively correlated primarily with many lignin-derived ions and to a lesser degree with m/z 114, deriving from a lactone produced from xylose pyrolysis. Models were capable of predicting glucose and xylose contents with an average error of less than 4%, and accuracy was significantly improved over previously used methods. The differences in the models constructed from the two sample sets varied in training sample number, but the genetic and compositional uniformity of the pedigree set could be a potential driver in the slightly better performance of that model in comparison with the natural variants. Broad-sense heritability of glucose and xylose composition using these data was 0.32 and 0.34, respectively. In summary, we have demonstrated the use of a single high-throughput method to predict sugar and lignin composition in thousands of poplar samples to estimate the heritability and phenotypic plasticity of traits necessary to develop optimized feedstocks for bioenergy applications.

Nutritional potential of Red Jambo fruit: dietary fibers, minerals, antioxidant potential, and bioaccessibility of phenolic compounds

Red jambo (RJ) is used by traditional medicine to treat diabetes, so far there are no reports on the relationship of its fiber content with monosaccharide composition and the bioaccessibility of the phenolic compounds. The aim of this study was to characterize the nutritional profile, minerals, the composition of sugars, the antioxidant potential, and the phenolic compounds accessibility of the fruit edible parts (pulp and peel). Considering the edible fraction, the major minerals were manganese, iron, magnesium, and zinc, suggesting that they can contribute to the recommended daily intake for adults. The monosaccharide composition showed that both the pulp and the peel have as main composition glucose (50.1% and 68.4%) and uronic acids (38.4% and 20.6%), respectively. Also, the contents of bioactive compounds and the antioxidant potential of the fruit are relatively high in the pulp and peel fractions, mainly for DPPH assay. Moreover, fourteen phenolic compounds were identified. Among them, p-coumaric and trans-cinnamic acids showed the highest bioaccessibility. We suggest the use of RJ in new nutraceutical and food products since it is a natural source of compounds with natural antioxidants.

Modulation of Mucin Secretion in the Gut of Young Pigs by Dietary Threonine and Non-Essential Amino Acid Levels.

Simple SummaryThe mucus layer is an important part of the system protecting the gut against injuries and bacterial infections. The main components of mucus responsible for its properties are mucins. They are large glycoproteins with a protein core rich in threonine (Thr) and many sugar side chains that differ in structure and affect mucin functions. Diet composition affects the amount of secreted mucins and their quality. Therefore, the aim of the study was to determine the effect of Thr and wheat gluten (WG) protein, added as a source of non-essential amino acids, on the content of tissue and luminal mucins in different parts of the intestine of young pigs. Results showed that tissue and luminal mucin content was only affected by WG levels in the duodenum and middle jejunum, and in the proximal colon, respectively. The effect of WG on luminal mucin content in the proximal colon depended on the analytical method applied.The aim of the study was to determine the effect of threonine (Thr) and non-essential amino acid (NEAA) levels on mucin secretion and sugar composition of digesta and crude mucin preparations analyzed in different segments of the gut in young pigs. A two-factorial experiment was conducted on 72 pigs using the following factors: Thr level (5.1, 5.7, 6.3 and 6.9 g standardized ileal digestible(SID) Thr/kg) and wheat gluten (WG) level used as a source of NEAA (20.4, 40.4 and 60.4 g WG protein in WG20, WG40 and WG60 diets, respectively). Mucin content was affected only by WG level. Tissue mucin content in the duodenum was higher in WG60 pigs than in WG20 and WG40 pigs, whereas in the middle jejunum was higher in WG40 and WG60 pigs than in WG20 pigs. In contrast, luminal crude mucin content in the proximal colon was lower in WG60 pigs compared to WG40 pigs. The lowest and highest Thr levels reduced arabinose and xylose contents and increased glucose content in ileal digesta. The highest WG level reduced arabinose and xylose contents and increased glucose content in ileal digesta. The lowest WG level increased mannose content in ileal digesta. WG60 level decreased the content of arabinose and galactose compared to lower WG levels in colonic digesta. Arabinose content was higher, while glucose and galactose contents were lower in crude mucin preparations isolated from colonic digesta in pigs fed diets containing the highest Thr level. The content of tissue mucin was higher in the ileum and proximal colon and lower in the duodenum than in the middle jejunum, whereas luminal mucin content was lower in the proximal colon than in the ileum. Ileal digesta contained less arabinose and glucose and more galactose as compared to colonic digesta. In conclusion, no effect of dietary Thr levels on mucin secretion in the gut of young pigs was found. Wheat gluten added to the diet with adequate Thr content positively affected mucin secretion only in the duodenum and middle jejunum.

Extraction of the Bacterial Extracellular Polysaccharide FucoPol by Membrane-Based Methods: Efficiency and Impact on Biopolymer Properties.

In this study, membrane-based methods were evaluated for the recovery of FucoPol, the fucose-rich exopolysaccharide (EPS) secreted by the bacterium Enterobacter A47, aiming at reducing the total water consumption and extraction time, while keeping a high product recovery, thus making the downstream procedure more sustainable and cost-effective. The optimized method involved ultrafiltration of the cell-free supernatant using a 30 kDa molecular weight cut-off (MWCO) membrane that allowed for a 37% reduction of the total water consumption and a 55% reduction of the extraction time, compared to the previously used method (diafiltration-ultrafiltration with a 100 kDa MWCO membrane). This change in the downstream procedure improved the product’s recovery (around 10% increase) and its purity, evidenced by the lower protein (8.2 wt%) and inorganic salts (4.0 wt%) contents of the samples (compared to 9.3 and 8.6 wt%, respectively, for the previously used method), without impacting FucoPol’s sugar and acyl groups composition, molecular mass distribution or thermal degradation profile. The biopolymer’s emulsion-forming and stabilizing capacity was also not affected (emulsification activity (EA) with olive oil, at a 2:3 ratio, of 98 ± 0% for all samples), while the rheological properties were improved (the zero-shear viscosity increased from 8.89 ± 0.62 Pa·s to 17.40 ± 0.04 Pa·s), which can be assigned to the higher purity degree of the extracted samples. These findings demonstrate a significant improvement in the downstream procedure raising FucoPol’s recovery, while reducing water consumption and operation time, key criteria in terms of process economic and environmental sustainability. Moreover, those changes improved the biopolymer’s rheological properties, known to significantly impact FucoPol’s utilization in cosmetic, pharmaceutical or food products.

Genotype influence on shelf life behaviour of minimal processed loquat (Eriobotrya japonica (Thunb.) Lindl.) fruit: the role of sugar, acid organics and phenolic compounds

BackgroundLoquat cultivars cultivated in Southern Italy are very appreciated by consumers for their sensorial characteristics, such as persistent aroma and taste. Apposite maturity indexes for peeling and processing loquat fruit were investigated to increase diffusion of minimally processed loquat. The genotype’s effect on the minimally processed loquat fruit shelf life and quality harvested at commercial maturity (80% yellow color) was investigated on peeled fruit stored at 5 °C for 10 days. The role of sugars, organic acids and phenols composition was observed through in depth qualitative analysis. In addition, several qualitative analyses were carried out to determine the quality of minimal processed fruit.ResultsLoquat fruits harvested at commercial ripening stage performed very good palatability and flesh color persistency. Late ripening fruits genotypes shown a low rate of pulp oxidation and quality decay, while early ripening fruits were not suitable for fresh-cut. Genotype had a great influence on weight loss, β-carotene content, fruit respiration, ascorbic acid and total phenols content during the shelf life.ConclusionsThis work shows how the amount of the composition of sugars and organic acids as an intrinsic characteristic of genotype influences the quality of loquat fruits minimal processed. The higher values of glucose, sorbitol and ascorbic acid accumulated in the cv ‘Nespolone Trabia’ contributed to a reduction in chilling injury and oxidative stress after cutting.Graphical

Correlation-Based Network Analysis of the Influence of Bemisia tabaci Feeding on Photosynthesis and Foliar Sugar and Starch Composition in Soybean

Simple SummaryBemisia tabaci affects plant performance by feeding directly from its energy sources, making it difficult to quantify crop damage, which is indirectly assessed through losses in productivity. The goal of this study was to characterize the influence of B. tabaci feeding on soybean, an economically valuable crop, and attempt to identify the optimal parameter for direct quantification of crop damage. A correlation network was created to extract biological interactions between the plant and B. tabaci nymphs at different densities and plant stages. Nymphs were more abundant during the vegetative stage, and a strong correlation between the density of nymphs and starch and fructose content was observed. The photosynthetic parameter turn-over number N was positively correlated with nymph density at a low-infestation level and negatively correlated with nymphs when they occur at a high infestation level. This association between nymph density and N may allow for development of a ranking scale to predict pest density, representing a useful tool for evaluating the potential impact of B. tabaci on soybean, especially in large areas, where nymph monitoring can be time-consuming.Bemisia tabaci (MEAM1) represents a species of economic importance in soybean. One of the obstacles to the management of B. tabaci is the quantification of damage by the pest because damage is indirectly inferred through losses in productivity. The objective of this study was to characterize the influence of B. tabaci feeding on soybean by assessing effects on photosynthetic parameters and the sugar and starch content of soybean leaves. The goal was to identify the optimal parameter to directly quantify pest damage on crop yield. Correlation networks were created among data on sugar content (fructose, glucose, and sucrose), starch and photosynthetic parameters (initial fluorescence, performance index on absorption basis, and turn-over number), and the number of nymphs at each of three infestations level (low, medium, and high) during both the vegetative and reproductive stage of the crop. In general, nymphs were more abundant during the vegetative stage. Starch content was strongly correlated with nymph density. A strong positive correlation was observed between fructose and nymph density during the vegetative stage. Among the photosynthetic parameters, the turn-over number N was positively correlated with nymph density at a low-infestation level and negatively correlated with nymphs when they occurred at a high-infestation level. B. tabaci feeding affected the plant’s physiology and its interaction is reflected in part by the relationships among photosynthetic parameters as well as the levels of sugars and starch. This understanding might be useful in developing better monitoring tools for pest management.

Nectaries in ferns: their taxonomic distribution, structure, function, and sugar composition.

Extrafloral nectaries have mainly been studied in angiosperms, but have also been reported in 39 fern species. Here we provide a global review of nectaries in ferns and examined their structure, function, and nectar sugar composition in two genera. We searched in the literature and living plant collections of botanical gardens for indications of fern nectaries, observed nectar-feeding animals, studied the morphoanatomy in the two genera Aglaomorpha and Campyloneurum, and analyzed the total sugar concentrations and ratios of 16 species. Diurnal nectar release was observed with time-lapse photography. We found evidence for nectaries in 101 species of ferns from 11 genera and 6 families. Most of the nectary-bearing species were tree ferns (Cyatheaceae) and epiphytic ferns of the family Polypodiaceae. Nectaries consisted of cytoplasm-rich parenchyma with large nuclei and an epidermis with or without stomata, were attached to amphiphloic vascular bundles, and released nectar on the lower leaf surface mainly on expanding leaves during the night. Sugar concentrations varied between species (3.8-15.3%) but not between genera, and were sucrose-dominant (3 spp.), sucrose-rich (7), or hexose-rich (3). In the greenhouse, introduced ants, scale insects, and snails fed on the nectar. The wide taxonomic distribution, variable morphology, locations, and sugar compositions point to multiple evolutionary origins of fern nectaries. Nectar release in young leaves might attract mutualistic ants to protect leaves against herbivores only during this most vulnerable developmental stage. Even ex-situ, fern nectar is a valuable food source because it attracted several opportunistic animal species.

Highlighted articles for January 2022.

Highlighted articles for January 2022.

Perfil fenólico, composição de ácidos orgânicos e de açúcares de feijoa (Acca sellowiana (O. Berg) Burret) e uvaia (Eugenia pyriformis Cambess) do planalto sul brasileiro

ABSTRACT: Brazil is a large country with high biodiversity in its different regions. However, species of native fruits widely reported in the southern Brazil have not been properly explored so far, remaining underutilized by the food industry. This study evaluated the polyphenolic profile, as well as the composition of organic acids and sugars of the pulps of the feijoa, and the uvaia from southern brazilian highlands. The uvaia pulp showed the highest total polyphenol content and the highest antioxidant capacity by the methods used. The polyphenol (+)-catechin (6.54 mg 100g-1) was the major phenolic compound in uvaia pulp, which has not yet been reported in the literature for fruits of other regions. In addition, the feijoa pulp stood out for the presence of (-)-epicatechin (18.29 mg 100g-1). The pulps of native fruits in this study only quantified values for citric and malic acids. Malic acid (553.00 mg 100g-1) was the main acid in the uvaia pulp, and citric acid (455.60 mg 100g-1) was the main acid in the feijoa pulp. It is possible to note that the feijoa pulp showed the highest total sugar content (11.14 g 100g-1) and was the only pulp that contained sucrose. The uvaia pulp, conversely, showed fructose (3.10 g 100g-1) as the main sugar. The results obtained in this study contributed to the valuation and conservation of the species investigated, representing a promising alternative for the use of these native fruits in the development of new products.