In bark

The common hemiceUulose components of arborescent plants are listed in Table 3. Xylans, arabinogalactans, and pectic substances are common to all while only traces (if at all) of glucomaimans are found in the cell walls of bamboo. Other polysaccharides are found in trace amounts in wood as well as in bark, growing tissues, and other specialized parts of trees. 

Tannins usuaUy occur in bark but may also be in the wood of some species, such as redwood and oak. 

Chelerythrine ( ), a- and 3-aZZocryptopine. Chelerythrine. One per cent, in bark none in... 

Evidence for de novo synthesis of pheromone components was obtained by showing that labeled acetate and mevalonate were incorporated into ipsdienol by male Ips pini [103,104]. Similarly, labeled acetate and other labeled intermediates were shown to be incorporated into frontalin in a number of Dendroctonus species [105]. Possible precursors to frontalin include 6-methyl-6-hep-ten-2-one, which was incorporated into frontalin by D. ruffipennis [106]. The precursor 6-methyl-6-hepten-2-one also was shown to be converted to bre-vicomin in the bark beetle, Dendroctonus ponderosae [107]. In addition, the expression patterns of HMG-CoA reductase and HMG-CoA synthase are tightly correlated with frontalin production in Dendroctonus jeffreyi [108, 109]. A geranyl diphosphate synthase cDNA from I. pini was also isolated, functionally expressed, and modeled [110]. These data indicate that the de novo isoprenoid biosynthetic pathway is present in bark beetles. A variety of other monoterpene alcohols such as myrcenol, pityol, and sulcitol are probably synthesized through similar pathways [111]... 

M.M. O Connell, M.D. Bentley, C.S. Campbell, B.J.W. Cole, Betulin and lupeol in bark from four white barked birches, Phytochemistry, 27, 2175 2176 (1988). 

Barreto JC, Trevisan MT, Hull WE, Erben G, de Brito ES, Pfundstein B, Wurtele G, Spiegelhalder B and Owen RW. 2008. Characterization and quantitation of polyphenolic compounds in bark, kernel, leaves, and peel of mango (Mangifera indica L.). J Agric Food Chem 56(14) 5599—5610. 

Soilborne fungal disease, which enters through cracks in bark, or wounds caused by the raspberry midge. It is spread by rain-splash and on tools. 

Small brown aphid living in colonies on stems and branches, protected by a white waxy substance that looks like cotton batting. They are most conspicuous in late spring and early summer. Young aphids overwinter in cracks in bark. 

Source Strychnine silver morning glory, wood rose, and in Strychnosnusvomica L. 15,800,400-12,000,8,000, and 7,030 ppm in bark, seeds, leaves, and roots, respectively (Duke, 1992). 

Triterpenes (C30) are common in birches, especially in bark. Papyriferic acid from paper birch, Betula resinifera, is a feeding deferent for snowshoe hares, Lepus americanus Big. 11.5) (Reichardt etal, 1985). 

Cates, Rex G. Alexander, H. J. In "Bark Beetles In North American Conifers Ecology and Evolution" J. Mltton and K. Sturgeon, (Eds.) University of Texas Press Austin, Texas, In press. 

Warington proposes to estimate the tannin, not only in barks, but in all other astringent substances volumetrically, hy determining what volume of a standard solution of gelatin is required to precipitate the tannin from the extract prepared from the Bample submitted to examination. In preparing the test solution, the above chemist recommends the long staple... 

Phlorid-an in bark of fmu trees C2I HyjOio 2H20 108 glucose phloreiin... 

The approach "select favorable raw material has a major impact on the selection of pretreatment processes. For example, the poplar responds splendidly to many pretreatments that fail with Douglas fir or pine-based materials (I). Specific tissues and cells of a given biomass raw material will respond quite differently. For example, the rind fiber of sugarcane bagasse behaves quite differently from the pith fiber (11)- In woody species, the selection of tissues low in bark and extractives is an important factor in the ease or resistance to cellulose hydrolysis. Before embarking on development of processes for hydrolysis of a biomass resource, it is highly desirable to exercise discretion with respect to the choice of raw materials at both the species and tissue levels. This idea is all the more important in an initial choice of species and pretreatment process. 

The frequency scale /(in Hz) is transformed to a pitch scale z (in Bark) and the signal is filtered with the transfer function a(i (z) from outer to inner ear (free or diffuse field). This results in the power-time-pitch representations px (t, z) and py(l, z) measured in (dB, seconds, Bark). A more detailed description of this transformation is given in Appendix A of [Beerends and Stemerdink, 1992]. 

Because of the small y that was found in the optimization the resulting density as function of pitch (in Bark) and time does not represent the loudness density but a compressed loudness density. The integrated difference between the density functions of the input and the output therefore does not represent the loudness of the noise but the compressed loudness of the noise. 

Gregory and Root in 1961 (9) prepared what they termed a "statistical analysis" of the literature covering bark utilization and, in addition, reviewed examples of commercial and pilot plant operations. They found 52 references on use of bark in composition boards. The report concludes with sections covering "Limitations and Hurdles in Bark Utilization" and a discussion of "Future Opportunities."... 

Renewed interest in bark particleboard was evidenced by a short article written by Murphey and Rishel (39). They reported results of preliminary studies on relative strengths of various bark species compared to aspen flakeboard. Bark species included aspen, black locust, green oak, white pine, oak and locust, poplar, red oak, and mixed oak. Overlaying was suggested as a means of increasing bending strengths. 

In no model pheromone biosynthetic system is the molecular mechanism of hormonal regulation completely understood. The mechanism of action of JH and the nature of its receptor remain one of the mysteries of insect science, and the clear-cut action of JH by itself in inducing specific genes in pheromone production in bark beetles offers an excellent model for study. A better understanding of the PBAN receptor and the second messenger system it triggers as well as the steps regulated in pheromone biosynthesis is also needed. The next several years should see some of the key questions answered in model insects. 

Figure 6.12 Cyclization reactions of acyclic, unbranched and methyl-branched ketones to bicyclic acetals and cyclic alcohols in bark beetles. (A) Mountain pine beetle, Dendroctonus ponderosae formation of exo-brevicomin [(1 F ,5S,7fl)-(+)-7-ethyl-5-methyl-6,8-dioxabicyclo[3.2.1]octane] from (Z)-6-nonen-2-one (Vanderwel and Oehlschlager, 1992 Vanderwel ef a/., 1992a) ...

Figure 6.13 Examples of the application of normal-phase, radio-HPLC to the analysis of de novo biosynthetic pathways in bark beetles (Scolytidae). Demonstration of sex-specific de novo biosynthesis of ipsenol, ipsdienol, and amitinol through radio-HPLC analysis of pentane extracts of Porapak-trapped volatiles from (A) male and (B) female Ips paraconfusus Lanier feeding for 168 h in Pinus ponderosa and (C) male and (D) female Ips pini (Say) feeding for 168 h in Pinus jeffreyi (Seybold et al., 1995b). Demonstration of sex-specific de novo biosynthesis of frontalin through radio-HPLC analysis of pentane extracts of Porapak-trapped volatiles from (E) male and (F) female...

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