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Changes in carbohydrate composition in wheat and pea seedlings induced by calcium deficiency 下载免费PDF全文
Wheat (Triticum aestivum L. cv Jubilar) seedlings were grown for 10 days in hydroponics with or without calcium. In the leaves, Ca deficiency caused the level of ethanol soluble carbohydrate to increase between 2-and 10-fold, enhanced dark respiration and decreased CO2 fixation capacity. Sucrose was the major carbohydrate to accumulate in wheat roots. 相似文献
24.
M. Kopecká 《Folia microbiologica》1984,29(6):441-449
The effect of papulacandin B on regenerating protoplasts ofSaccharomyces cerevisiae was studied by light and electron microscopy. In liquid media it inhibited the biogenesis of (1→3)-β-d-glucan fibrillar nets; as a result, the protoplasts did not grow polarly but only spherically. The effect was reversible.
Instead of the nets the inhibited protoplasts synthesized only individual microfibrils soluble in hydroxide; these were not
joined in the nets and were partially masked by amorphous material. The microfibrils disintegrated after lysis and did not
maintain the shape of protoplasts. Protoplasts inhibited in solid media grew spherically up to 25 μm but they did not divide
or revert or revert, in spite of forming cell walls. These walls were amorphous and fragile and they disintegrated during
preparation. Papulacandin B did not decrease the viability of protoplasts and did not interfere with their growth, biogenesis
of alkali-soluble glucan microfibrils or amorphous wall matrix. It inhibited specifically the synthesis of alkali-insoluble
branched (1→3)-β-d-glucan, a necessary building unit required for the formation of the fibrillar component of the cell wall responsible for
the cell wall shape, its rigidity and tensile strength. 相似文献
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26.
Zdeněk Hostounský 《Journal of invertebrate pathology》1984,44(2):166-171
The microsporida Nosema gastroideae and N. equestris, which are highly pathogenic for Leptinotarsa, have been successfully produced in some other chrysomelid species, Gastrophysa polygoni and G. viridula. As the principal target host, Leptinotarsa is very susceptible to these pathogens, and death occurs before massive sporulation by the microsporidia. By contrast, the infected larvae of G. polygoni or G. viridula are able to develop until the adult stage when most of the tissues become filled with spores. In addition, the larvae and adults of these species can be reared in the laboratory on Polygonum aviculare and Rumex obtusifolius. These plants have longer vegetative periods and are better sources of food than potato leaves. In both species of Gastrophysa the yields of spores related to unit weight were about five times higher than in Leptinotarsa. In the adults of G. viridula there was up to 4.8 × 106 spores mg?1 body weight of N. gastroideae, or 9.1 × 106 spores mg?1 of N. equestris. The higher content of microsporidian spores facilitates their purification and isolation. 相似文献
27.
Jan Kopecký Josef Houštěk Eva Szarska Zdeněk Drahota 《Journal of bioenergetics and biomembranes》1986,18(6):507-519
The proteolipid subunit of H+-ATPase was labeled by [14C]N,N-dicyclohexylcarbodiimide in bovine heart mitochondria. The radioactive labeling was followed using various systems of sodium dodecylsulfate polyacrylamide gel electrophoresis (SDS-PAGE). When using discontinuous SDS-PAGE (Laemmli, U.K., 1970,Nature (London)227, 680–685) a monomeric (Mr 7600±1500) and a dimeric form (Mr 17,800±1200) of the proteolipid were detected, while only the monomeric form was found on urea (8 M) containing gels (SDS-PAGE according to Laemmli; or Swank, R. T., and Munkers, K. D., 1971,Anal. Biochem.
39, 462–477). When using SDS-PAGE with Na-Pi buffer (Weber, K., and Osborn, M., 1969,J. Biol. Chem.
244, 4406–4442), only a dimeric form of the proteolipid (Mr 15,000±1000) was detected. Experimental data indicate that the different patterns of proteolipid separation are related to the presence of the two distinct proteolipid conformations in the SDS solution. 相似文献
28.
Polymer chains of (13)--d-glucan were dissolved with 1 M NaOH at 4° C from native microfibrillar protoplast nets. The chains associated into microfibrils during NaOH neutralization or dialysis. In contrast to the native microfibrils which are of uniform width individually (10 to 20 nm) and arranged in flat bundles, the microfibrils formed in vitro showed no band formation and consisted of fibrous spindle-shaped subunits of variable width or loose elementary fibrils about 1.7 nm wide. X-ray diagrams of native nets indicated a fairly high crystallinity and were different for wet and dry specimens. They corresponded to those of paramylon. Precipitated glucans produced diagrams different from the former and revealing a lower crystallinity especially with the dry samples.The X-ray pattern, combined with other data, allowed the precipitated microfibrils to be identified as aggregates of molecular strands composed each of three intertwined helical glucan chains. Since these triple helical chains are about 1.7 nm wide the elementary fibrils of this width can represent only single triple-helical strands. These helices have 7 glucose residues per turn and therefore a low symmetry which explains the poor crystallizing properties. The 7 membered helix represents a basic difference with the well crystallized native glucan which is built of highly symmetrical triple helices with 6 glucose residues per turn. Since 61 helical conformation is not formed in vitro at normal temperatures its generation in vivo must be due to the action of synthesizing enzymes at the protoplast membrane. The intertwining of these helices and crystallization of the strands are determined by their symmetry and physical properties of the chains. This characterizes the native microfibrils as products of self-assembly of enzymegenerated 61 helices. 相似文献
29.
Respiration and microflora of the rhizosphere soil of wheat influenced by foliar application of urea
J. Vraný 《Folia microbiologica》1983,28(2):118-123
The numbers of micromycetes and bacteria were investigated with respect to oxygen consumption in the rhizosphere soil of wheat
and in non-rhizosphere soil. Plants after foliar application of urea (2 % solution) and non-treated plants were cultivated
in degraded chernozem and garden soil in a green-house. Changes in oxygen consumption by the suspensions of rhizosphere and
non-rhizosphere soils corresponded to changes in the number of bacteria designated as the rhizosphere effect (R/S). Values
of R/S depended on the presence of organic substrates. Changes in oxygen consumption by the soil suspension from the rhizosphere
of wheat occurring due to foliar application of urea corresponded to changes in the amount of microflora. The results obtained
are discussed with respect to a possible utilization of the data to follow metabolic activity of soils in a natural environment
(in situ) determined according to oxygen consumption by a soil suspension, and to assess changes in the microflora of rhizosphere
and non-rhizosphere soil. 相似文献
30.
Foreign proteins penetrate across the wall of rabbit jejunum takes place within the first eight hours after birth. Sensitization by foreign protein (cow's milk protein) during early postnatal ontogeny is the cause of death of artificially fed germfree rabbits at the age of 21-23 d. 相似文献