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This review focuses on the monoterpene, sesquiterpene, and diterpene synthases of plant origin that use the corresponding C10, C15, and C20 prenyl diphosphates as substrates to generate the enormous diversity of carbon skeletons characteristic of the terpenoid family of natural products. A description of the enzymology and mechanism of terpenoid cyclization is followed by a discussion of molecular cloning and heterologous expression of terpenoid synthases. Sequence relatedness and phylogenetic reconstruction, based on 33 members of the Tps gene family, are delineated, and comparison of important structural features of these enzymes is provided. The review concludes with an overview of the organization and regulation of terpenoid metabolism, and of the biotechnological applications of terpenoid synthase genes

This review surveys the literature dealing with the structure of pigments produced by fungi of the phylum Basidiomycota and also covers their significant colourless precursors that are arranged according to their biochemical origin to the shikimate, polyketide and terpenoid derived compounds. The main groups of pigments and their leucoforms include simple benzoquinones, terphenylquinones, pulvinic acids, and derived products, anthraquinones, terpenoid quinones, benzotropolones, compounds of fatty acid origin and nitrogen-containing pigments (betalains and other alkaloids). Out of three orders proposed, the concern is only focused on the orders Agaricales and Boletales and the taxonomic groups (incertae sedis) Cantharellales, Hymenochaetales, Polyporales, Russulales, and Telephorales that cover most of the so called higher fungi often referred to as mushrooms. Included are only the European species that have generated scientific interest due to their attractive colours, taxonomic importance and distinct biological activity.

Concentrations of nutrients and plant secondary metabolites (PSM) vary temporally and spatially, creating a multidimensional feeding environment. Interactions between nutrients and PSM are poorly understood because research has relied largely on studying the isolated effects of nutrients or PSM on foraging behavior. Nevertheless, their interactions can influence food selection and the dynamics of plant communities. Our objective was to explore how interactions between nutrients and PSM influence food selection. For 7 d, three groups of lambs received intraruminal infusions of three different doses of a PSM (0 = Control; low and high) and 2 h later they were offered two foods that contained either low (high in energy) or high (high in protein) protein/energy ratios. The foods were offered 7 d before (baseline) and 7 d after PSM infusions. We conducted five trials each with a different PSM-terpenoids, cyanogenic glycosides, sodium nitrate, quebracho tannin, and lithium chloride. Lambs consistently preferred the food high in energy to the food high in protein, but toxins modified the degree to which this preference was manifest. Terpenoids, nitrate, and lithium chloride depressed intake of the food high in energy. Cyanogenic glycosides had the opposite effect, and at higher doses they depressed intake of the food high in protein. Tannins enhanced intake of the food high in energy at lower doses and they depressed its ingestion at higher doses. Thus, PSM selectively depressed or enhanced intake depending on the macronutrient composition of the foods. These results imply that the probability of a plant being eaten will depend not only on its chemical defenses but also on the quantity and quality of nutrients in the plant and its neighbors, and that the ability of herbivores to learn associations between nutrients and PSM may have a substantial impact on the way herbivores regulate ecosystem processes.

The effect of malolactic fermentation (MLF) on the flavour quality of cider was examined. Leuconostoc mesenteroides subsp. mesenteroides Z25 was used to start MLF taking place at 25 deg C for 12 days after the completion of alcoholic fermentation (AF) by Saccharomyces cerevisiae. Strain Z25 showed good activity in starting MLF of cider with 10% alcoholic concentration. The content of malic acid, whose high concentration gives negative organoleptic characteristics to the cider, dropped significantly from 4.0 g/l to 0.25 g/l via MLF. The concentration of lactic acid increased significantly from 0.99 g/l to 3.50 g/l, contributing to volatile acidity. The acetic acid content of the ciders was 0.74 g/l. Among 51 volatile compounds detected by GC-MS, higher alcohols, esters, and carbonyl compounds were formed in ciders through MLF. The total concentration of aromatic substances doubled compared to the controls. The occurrence of MLF started by strain Z25 enabled the cider containing more volatile compounds and an acceptable adjustment of organic acids. This is the first report on using L. mesenteroides subsp. mesenteroides strain Z25 to start the MLF of apple wine improving the flavour quality of the cider produced.

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We determine the effect of substitution of sucrose with fructose on the physico-chemical composition and sensory characteristics of kinnow candy. Candy was prepared with peel using sucrose and fructose at the ratio of 100:0, 0:100, 75:25, 50:50, and 25:75 with 70 °B of TSS. Organoleptically, the candy prepared with 100% fructose proved the best but the candy prepared with 25:75 of sucrose to fructose was equally good. The least acceptable was the candy prepared with 100% sucrose, as it had a dull appearance and slight crystallisation was observed during storage. Moisture, acidity and ascorbic acid decreased while total soluble solids, reducing and total sugars and limonin increased with no change in ash content of the candies during four months of storage.

In this study, solid-phase micro-extraction (SPME) fibers coated with polydimethylsiloxane/divinylbenzene (PDMS/DVB), coupled with gas chromatography/mass spectrometry, were used to monitor the emission patterns of biogenic volatile organic compounds (BVOCs) from leaves of Calocedrus macrolepis var. formosana Florin. in situ. In both sunny and rainy weather, the circadian profile for BVOCs from C. macrolepis var. formosana leaves has three maximum emission cycles each day. This kind of emission pattern might result from the plant's circadian clock, which determines the rhythm of terpenoid emission. Furthermore, emission results from the leaves demonstrated that the circadian profile of alpha-pinene observed was opposite to the profiles of limonene and myrcene, a difference that may be attributable to two different sub-pathways for terpenoid biosynthesis.

Two pine species (Pinus resinosa, P. banksiana) responded to inoculation with fungi carried by bark beetles by rapidly increasing monoterpene concentrations at the entry site. Changes in total monoterpenes were more pronounced than changes in proportionate compositions. The extent and rate of host response was affected by fungal species, the viability of the inoculum, and host tree species. In general, host responses were highest to fungi that are phytopathogenic and consistently associated with the major bark beetles in the study region. Simple mechanical wounding cannot account for the observed allelochemical changes, as aseptic inoculations elicited only minor reactions. Similarly, inoculation with autoclaved inviable fungi generally elicited intermediate responses, suggesting that both structural and metabolic fungal properties are important. Responses by jack pine, P. banksiana, were generally more rapid and variable than those of red pine, P. resinosa. Dose-toxicity experiments with synthetic compounds demonstrated that monoterpene concentrations present in vivo only a few days after simulated attack are lethal to most beetles. Constitutive (pre-attack) monoterpene levels can also exert some toxicity. Because bark beetles engage in pheromone-mediated mass attacks that can deplete host defenses, constitutive monoterpene levels, while a necessary early phase of successful plant defense, appear insufficient by themselves. Such interactions between constitutive and induced defense chemistry may be important considerations when evaluating general theories of plant defense

Corn seedlings respond to insect herbivore-inflicted injury by releasing relatively large amounts of several characteristic terpenoids and, as a result, become highly attractive to parasitic wasps that attack the herbivores. Chemical evidence showed that the induced emission of volatiles is not limited to the sites of damage but occurs throughout the plant. This evidence was obtained by comparing the release of volatiles from leaves of unharmed (control) seedlings with the release of volatiles from undamaged leaves of seedlings with two injured leaves treated with caterpillar regurgitant. Immediately after injury no differences were measured in the released volatiles, but several hours later the undamaged leaves of injured plants released the terpenoids linalool, (3E)-4,8-dimethyl-1,3,7-nonatriene, and (3E,7E)-4,8,12-trimethyl-1,3,7,11-tridecatetraene in significantly larger amounts than leaves of unharmed plants. Other volatiles that are released by herbivore-injured leaves were detected occasionally only in trace amounts from the undamaged leaves of a damaged seedling. The systemic release of volatiles by injured corn coincided with attractiveness to the parasitoid Cotesia marginiventris; undamaged leaves of injured plants became significantly more attractive than leaves from control seedlings. These findings show conclusively that when a plant is injured by an insect herbivore the whole plant emits chemical signals.