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1.
Nutrients are assimilated efficiently by Lymantria dispar caterpillars from the mature leaves of trees in the Salicaceae 下载免费PDF全文
Raymond V. Barbehenn Jennifer Knister Frank Marsik Chelsea Jahant‐Miller William Nham 《Physiological Entomology》2015,40(1):72-81
The efficient aquisition of nutrients from leaves by insect herbivores increases their nutrient assimilation rates and overall fitness. Caterpillars of the gypsy moth (Lymantria dispar L.) have high protein assimilation efficiencies (PAE) from the immature leaves of trees such as red oak (Quercus rubra) and sugar maple (Acer saccharum) (71–81%) but significantly lower PAE from their mature leaves (45–52%). By contrast to this pattern, both PAE and carbohydrate assimilation efficiencies (CAE) remain high for L. dispar larvae on the mature leaves of poplar (Populus alba × Populus tremula) grown in greenhouse conditions. The present study tests two alternative hypotheses: (i) outdoor environmental stresses cause decreased nutrient assimilation efficiencies from mature poplar leaves and (ii) nutrients in the mature leaves of trees in the poplar family (Salicaceae) remain readily available for L. dispar larvae. When poplar trees are grown in ambient outdoor conditions, PAE and CAE remain high (approximately 75% and 78%, respectively) in L. dispar larvae, in contrast to the first hypothesis. When larvae feed on the mature leaves of species in the Salicaceae [aspen (Populus tremuloides), cottonwood (Populus deltoides), willow (Salix nigra) and poplar], PAE and CAE also remain high (68–76% and 72–92%, respectively), consistent with the second hypothesis. Larval growth rates are strongly associated with protein assimilation rates, and more strongly associated with protein assimilation rates than with carbohydrate assimilation rates. It is concluded that tree species in the Salicaceae are relatively high‐quality host plants for L. dispar larvae, in part, because nutrients in their mature leaves remain readily available. 相似文献
2.
T. V. Tyrtysh N. E. Byramova N. V. Bovin 《Russian Journal of Bioorganic Chemistry》2000,26(6):414-418
3-O-Acetyl and 3-O-benzoyl derivatives of 1,6-anhydro-N-acetyl-β-D-glucosamine were synthesized via its selective tritylation followed by the 3-O-acylation and removal of the trityl protective group. Tritylium trifluoromethanesulfonate, which can easily be prepared by
mixing solutions of triphenylcarbinol and trimethylsilyl trifluoromethanesulfonate in an equimolar ratio, was suggested as
a reagent for the effective tritylation of a secondary hydroxyl group.
This paper is dedicated to the 70th birthday of Prof. A. Ya. Khorlin. 相似文献
3.
John H. Pazur Belin Liu Steven Pyke Craig R. Baumrucker 《Journal of Protein Chemistry》1987,6(6):517-527
Glucoamylase is a starch-hydrolyzing enzyme with a glycoprotein structure, used industrially for the conversion of starch to glucose, citric acid, corn syrups, and high-fructose sweeteners. This enzyme possesses an unusual type of structure in which many carbohydrate side chains are linked O-glycosidically to serine and threonine residues of the polypeptide chain. The carbohydrate side chains may be single monosaccharide residues or oligosaccharides of mannose, glucose, galactose, and in some cases N-acetylglucosamine. New data from experiments on the CNBr fragmentation of glucoamylase followed by chemical and immunological characterization of the fragments show that the carbohydrate side chains are distributed randomly along the polypeptide chain. Such a structure is appropriately termed a random model reprensentation for the glucoamylase molecule. 相似文献
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Sabal palmetto (Walt.) Lodd. ex Schultes (cabbage palm) is an arborescent palm common in many plant communities throughout Florida, U.S.A.,
and the Caribbean. Although its seedlings grow very slowly in forest understories, they survive damage and defoliation well,
and the species may increase in dominance following disturbances such as fire, logging, and hurricanes. We investigated the
potential importance of total nonstructural carbohydrate (TNC) pools in the ability of cabbage palm seedlings to recover from
the loss of aboveground tissue such as that caused by fire, grazing, or shallow burial by storm debris. TNC concentrations
in belowground organs of seedlings from a forest understory were high, and TNC pools were sufficient to theoretically replace
>50% of a seedling's canopy. The largest fraction of the belowground TNC pool was in stem tissue, where TNC in unclipped plants
accounted for 26–54% of stem dry mass. Experimental reduction of TNC pools by repeated defoliation slowed seedling regrowth,
and seedlings with inherently smaller pools (smaller seedlings) suffered higher mortality after repeated defoliation than
did larger seedlings. Although regrowth and recovery after the loss of aboveground tissue was related to the size of the TNC
pool in belowground organs, even the smallest seedlings with the smallest pools had sufficient stores to withstand at least
two defoliations at frequent (7-week) intervals. Large belowground TNC pools in S. palmetto seedlings appear to enable them to survive all but the most frequent defoliations (e.g., frequent grazing or mowing). Allocation
of resources to these stores, however, may contribute to the slow growth rates of S. palmetto seedlings in natural communities.
Received: 13 April 1998 / Accepted: 28 August 1998 相似文献
9.
Jillian R. Brown Brett E. Crawford Jeffrey D. Esko 《Critical reviews in biochemistry and molecular biology》2013,48(6):481-515
ABSTRACTGlycans, the carbohydrate chains of glycoproteins, proteoglycans, and glycolipids, represent a relatively unexploited area for drug development compared with other macromolecules. This review describes the major classes of glycans synthesized by animal cells, their mode of assembly, and available inhibitors for blocking their biosynthesis and function. Many of these agents have proven useful for studying the biological activities of glycans in isolated cells, during embryological development, and in physiology. Some are being used to develop drugs for treating metabolic disorders, cancer, and infection, suggesting that glycans are excellent targets for future drug development. 相似文献
10.
Abstract The allocation of photosynthetically fixed carbon in the leaf blades and sheaths of Poa annua (a ruderal grass) and Poa x jemtlandica (a sub-arctic grass) was followed over a light-dark cycle. Labelling with 14Carbon and gas exchange measurements provide data for an eight-compartment model describing the partitioning of carbon between spatially and chemically separated pools and their rates of turnover. Soluble sugars and fructans were turned over rapidly in the leaf blades of both species. The flux of carbon through pools of storage carbohydrates was higher in the leaves of P. x jemtlandica than in P. annua. The exchange of carbon between pools was slower in the sheath than the blade. Carbohydrates stored in the sheath appeared to have no significant role in metabolism over the light-dark cycle studied here. 相似文献