Foliar herbivory increases sucrose concentration in bracteal extrafloral nectar of cotton

Cultivated cotton, such as Gossypium hirsutum L., produces extrafloral (EF) nectar on leaves (foliar) and reproductive structures (bracteal) as an indirect anti-herbivore defense. In exchange for this carbohydrate-rich substance, predatory insects such as ants protect the plant against herbivorous insects. Some EF nectar-bearing plants respond to herbivory by increasing EF nectar production. For instance, herbivore-free G. hirsutum produces more bracteal than foliar EF nectar, but increases its foliar EF nectar production in response to herbivory. This study is the first to test for systemically induced changes to the carbohydrate composition of bracteal EF nectar in response to foliar herbivory on G. hirsutum. We found that foliar herbivory significantly increased the sucrose content of bracteal EF nectar while glucose and fructose remained unchanged. Sucrose content is known to influence ant foraging behavior and previous studies of an herbivore-induced increase to EF nectar caloric content found that it led to increased ant activity on the plant. As a follow-up to our finding, ant recruitment to mock EF nectar solutions that varied in sucrose content was tested in the field. The ants did not exhibit any preference for either solution, potentially because sucrose is a minor carbohydrate component in G. hirsutum EF nectar: total sugar content was not significantly affected by the increase in sucrose. Nonetheless, our findings raise new questions about cotton’s inducible EF nectar responses to herbivory. Further research is needed to determine whether an herbivore-induced increase in sucrose content is typical of Gossypium spp., and whether it constitutes a corollary of systemic sucrose induction, or a potentially adaptive mechanism which enhances ant attraction to the plant

A triresidue motif in the GLUTAMATE RECEPTOR-LIKE 3.3 C-tail interacts with IMPAIRED SUCROSE INDUCTION 1 and controls long distance wound signaling

Arabidopsis Clade 3 GLUTAMATE RECEPTOR-LIKE (GLRs) genes are primary players in wound-induced electrical signaling and jasmonate-activated defense responses. As cation-permeable ion channels, previous studies have focused on resolving their gating properties and structures. However, little is known regarding to the regulatory mechanism of these channel proteins. Here, we report that the C-tail of GLR3.3 contains key elements that control its function in long distance wound signaling. GLR3.3 without its C-tail failed to rescue the glr3.3a mutant. To further investigate the underlying mechanism, we performed a yeast two-hybrid screen. IMPAIRED SUCROSE INDUCTION 1 (ISI1) was identified as an interactor with both the C-tail and the full-length GLR3.3 in planta. Reduced function isi1 mutants had enhanced electrical activity and jasmonate-regulated defense responses. Furthermore, we found that a triresidue motif RFL (R884, F885 and L886) in the GLR3.3 C-tail is essential for interacting with ISI1. RFL mutation abolished GLR3.3 function in electrical signaling and jasmonate-mediated defense gene activation. Our study shows the importance of the C-tail in GLR3.3 function, and reveals parallels with the ipnotropic glutamate receptor regulation in animal cells.

Impact of high-energy diets on the rumen environment and digital cushion in confined cattle

ABSTRACT: This study aimed to identify gross and microscopic changes, caused by high-energy diets, in the rumen environment and hoof of confined beef cattle. The study sample comprised 40 confined heifers (Bos taurus) with no disease history divided into four experimental groups using different diets: Group 1 (D1, control), 48:52 forage:concentrate ratio; Group 2 (D2), 30:70 forage:concentrate ratio; Group 3 (D3), 30:70 forage:concentrate ratio + sucrose; Group 4 (D4), 100% concentrate. All animals underwent clinical examination, assessment of ruminal fluid pH and lameness, and sample collection after slaughter for histopathology of the hoof laminae and digital cushion and ruminal tissue. All dependent variables of the study were compared using the SPSS 20.0 statistical software. The variables that did not show normality (HR, RM, ST, and CRT) were compared with application of the Kruskal-Wallis test followed by the Dunnet’s multiple comparison test. All other variables were submitted to analysis of variance (ANOVA) followed by Tukey’s test. The different diets had an impact on the rumen environment (p<0.05) of the heifers assessed, with momentary general depression in the first 12 h after sucrose induction (D3), as well as mild clinical signs in D4. The animals in D3 and D4 presented lower motility (p<0.05) and ruminal pH (p<0.01) than those in D1. Of the 40 heifers, 27.5% (n=11) showed gross lesions in the epithelium of ruminal pillars, whereas 22.5% (n=9) of those in D3 and D4 presented these lesions. Sole corium thickness varied between heifers in D3 compared with those in D1 and D2 (p<0.05). Therefore, high-energy diets, as used in this study, alter some clinical parameters and the rumen environment, causing lesions in the rumen mucosa, and of lesser intensity, in the hoof corium and laminae, suggestive of laminitis.

Heterologous glycosyl hydrolase expression and cellular reprogramming resembling sucrose-induction enable Zymomonas mobilis growth on cellobiose

ABSTRACTPlant derived fuels and chemicals from renewable biomass have significant potential to replace reliance on petroleum and improve global carbon balance. However, plant biomass contains significant fractions of oligosaccharides that are not usable natively by many industrial microorganisms, including Escherichia coli, Saccharomyces cerevisiae, and Zymomonas mobilis. Even after chemical or enzymatic hydrolysis, some carbohydrate remains as non-metabolizable oligosaccharides (e.g., cellobiose or longer cellulose-derived oligomers), thus reducing the efficiency of conversion to useful products. To begin to address this problem for Z. mobilis, we engineered a strain (Z. mobilis GH3) that expresses a glycosyl hydrolase (GH) with β-glucosidase activity from Caulobacter crescentus and subjected it to an adaptation in cellobiose medium. Growth on cellobiose was achieved after a prolonged lag phase in cellobiose medium that induced changes in gene expression and cell composition, including increased expression and secretion of GH. These changes were reversible upon growth in glucose-containing medium, meaning they did not result from genetic mutation but could be retained upon transfer of cells to fresh cellobiose medium. After adaptation to cellobiose, our GH-expressing strain was able to convert about 50% of cellobiose to glucose within 24 hours and use it for growth and ethanol production. Alternatively, pre-growth of Z. mobilis GH3 in sucrose medium enabled immediate growth on cellobiose. Proteomic analysis of cellobiose- and sucrose-adapted strains revealed upregulation of secretion-, transport-, and outer membrane-related proteins, which may aid secretion or surface display of GHs, entry of cellobiose into the periplasm, or both. Our two key findings are that Z. mobilis can be reprogrammed to grow on cellobiose as a sole carbon source and that this reprogramming is related to a natural response of Z. mobilis to sucrose that enables sucrose secretion.

Analisis Kadar Glukosa, Hemoglobin, dan Kolesterol Mencit (Mus Musculus) Setelah Diinduksi Aspartam

Aspartame has a lower calorie rating than other sweeteners. for example, cyclamate, lactose, saccharin, fructose and maltosa. Although it has low calorie, aspartame have 60 times sweeter than sugar (sucrose). Induction of aspartame can cause elevated levels of blood glucose and damage to the pancreatic β cells of mice. The purpose of this study was to analyze the dosing of aspartame levels; 13 mg/Kg body weight, 39 mg/Kg and 78 mg/Kg and those effect to the levels of glucose, cholesterol and haemoglobin of female mice (Mus musculus). The methode of research laboratory experiments using a complete randomized design (RAL). This study was using 24 mice with 4 treatment groups. Mice were given aspartame during surgical treatment, mice were made to perform measurement of Hb levels, glucose levels and cholesterol levels of neonatal mice. Data analysis using the Kruskal Wallis because Gaussian data but not homogeneous. The results showed an increase in the levels of glucose and cholesterol levels, but statistically there is no difference in glucose levels (p = 0,087), Hb (p = 0,899) and cholesterol (p = 0,168) in mice (Mus musculus) who were given variations of the dose of aspartame.

Flavonoid Compounds Are Enriched in Lemon Balm (Melissa officinalis) Leaves by a High Level of Sucrose and Confer Increased Antioxidant Activity

Medicinal plants are widely used in traditional medicine because plant secondary metabolites have been shown to benefit a broad spectrum of health conditions. Lemon balm, Melissa officinalis L., a member of the mint family, is native to Europe and is well known for its ability to reduce stress and anxiety, promote sleep, and ease pain and discomfort associated with digestion. In various plant species, strong anthocyanin induction is triggered by sucrose, but not by other sugars or osmotic stress; however, the mechanisms that induce anthocyanin accumulation in lemon balm leaves in response to sucrose and phytohormones remain unclear. In this study, we investigated the mechanisms that lead to increased levels of flavonoids in lemon balm plants. We observed that sucrose significantly increases the level of flavonoids in lemon balm plants and that sucrose induction appears to be mediated by the phytohormones abscisic acid and ethylene. We also identified delphinidin as the anthocyanidin that is primarily enriched in leaves grown in high-sucrose medium. Finally, we observed that reactive oxygen species levels are positively correlated with sucrose-mediated anthocyanin accumulation. Taken together, our results demonstrate that the level of flavonoids in lemon balm can be increased significantly and that plants such as lemon balm could potentially be used to prevent diseases that have been purported to be caused by free radical damage. Chemical abbreviations used: ABA, (+)-cis, transabscissic acid; ACC, 1-aminocyclopropane-carboxylic acid; CHI, chalcone isomerase; CHS, chalcone synthase; DPPH, 2, 2-diphenyl-1-picrylhydrazyl; GA, gibberellic acid; IAA, indole-3-acetic acid.

Molecular and Functional Characterization of a Unique Sucrose Hydrolase from Xanthomonas axonopodis pv. glycines

ABSTRACT A novel sucrose hydrolase (SUH) from Xanthomonas axonopodis pv. glycines, a causative agent of bacterial pustule disease on soybeans, was studied at the functional and molecular levels. SUH was shown to act rather specifically on sucrose (Km = 2.5 mM) but not on sucrose-6-phosphate. Protein analysis of purified SUH revealed that, in this monomeric enzyme with an estimated molecular mass of 70,223 ± 12 Da, amino acid sequences determined for several segments have corresponding nucleotide sequences in XAC3490, a protein-coding gene found in the genome of X. axonopodis pv. citri. Based on this information, the SUH gene, consisting of an open reading frame of 1,935 bp, was cloned by screening a genomic library of X. axonopodis pv. glycines 8ra. Database searches and sequence comparison revealed that SUH has significant homology to some family 13 enzymes, with all of the crucial invariant residues involved in the catalytic mechanism conserved, but it shows no similarity to known invertases belonging to family 32. suh expression in X. axonopodis pv. glycines requires sucrose induction, and insertional mutagenesis resulted in an absence of sucrose-inducible sucrose hydrolase activity in crude protein extracts and a sucrose-negative phenotype. Recombinant SUH, overproduced in Escherichia coli and purified, was shown to have the same enzymatic characteristics in terms of kinetic parameters.