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1.
4-O-Glycosylation of 2-azidoethyl 2,3,6-tri-O-benzyl-4-O-(2,3-di-O-benzyl-6-O-benzoyl--D-galactopyranosyl)--D-glucopyranoside with a disaccharide donor, 4-trichloroacetamidophenyl 4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-1-thio-2-trichloroacetamido--D-galactopyranoside, in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid resulted in a tetrasaccharide, 2-azidoethyl (2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-(1 3)-(4,6-di-O-acetyl-2-deoxy-2-trichloroacetamido--D-galactopyranosyl)-(1 4)-(2,3-di-O-benzyl-6-O-benzoyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside, in 69% yield. The complete removal of O-protecting groups in the tetrasaccharide, the replacement of N-trichloroacetyl by N-acetyl group, and the reduction of the aglycone azide group to amine led to the target aminoethyl glycoside of -D-Gal-(1 3)--D-GalNAc-(1 4)--D-Gal-(1 4)--D-Glc-OCH2CH2NH2 containing the oligosaccharide chain of asialo-GM1 ganglioside in 72% overall yield. Selective 3-O-glycosylation of 2-azidoethyl 2,3,6-tri-O-benzyl-4-O-(2,6-di-O-benzyl--D-galactopyranosyl)--D-glucopyranoside with thioglycoside methyl (ethyl 5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-2-thio-D-glycero--D-galacto-2-nonulopyranosyl)oate in acetonitrile in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid afforded 2-azidoethyl [methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero--D-galacto-2-nonulopyranosyl)oate]-(2 3)-(2,6-di-O-benzyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside, the selectively protected derivative of the oligosaccharide chain of GM3 ganglioside, in 79% yield. Its 4-O-glycosylation with a disaccharide glycosyl donor, (4-trichloroacetophenyl-4,6-di-O-acetyl-2-deoxy-3-O-(2,3,4,6-tetra-O-acetyl--D-galactopyranosyl) 1-thio-2-trichloroacetamido--D-galactopyranoside in dichloromethane in the presence of N-iodosuccinimide and trifluoromethanesulfonic acid gave 2-azidoethyl (2,3,4,6-tetra-O-acetyl--D-galactopyranosyl)-(1 3)-(4,6-di-O-acetyl-2-deoxy-2-trichloroacetamido--D-galactopyranosyl)-(1 4)-{[methyl (5-acetamido-4,7,8,9-tetra-O-acetyl-3,5-dideoxy-D-glycero--D-galacto-2-nonulopyranosyl)onate]-(2 3)}-(2,6-di-O-benzyl--D-galactopyranosyl)-(1 4)-2,3,6-tri-O-benzyl--D-glucopyranoside in 85% yield. The resulting pentasaccharide was O-deprotected, its N-trichloroacetyl group was replaced by N-acetyl group, and the aglycone azide group was reduced to afford in 85% overall yield aminoethyl glycoside of -D-Gal-(1 3)--D-GalNAc-(1 4)-[-D-Neu5Ac-(2 3)]--D-Gal-(1 4)--D-Glc-OCH2CH2NH2 containing the oligosaccharide chain of GM1 ganglioside.  相似文献   

2.
Liver homogenate-supernatants from most Japanese exhibit an atypical pH optimum for ethanol oxidation at pH 8.8 instead of 10.5, the typical pH-activity optimum. It has been proposed that atypical livers contain alcohol dehydrogenase isozymes with 2 subunits while typical livers contain isozymes with 1 subunits, both produced by the ADH 2 gene. Because it is difficult to differentiate the atypical ADH2 2-2 phenotype from the ADH2 2-1 phenotype by starch gel electrophoresis, an agarose isoelectric focusing procedure was developed that clearly separated the atypical Japanese livers into two groups, A1 and A2. The isozymes in A1 and A2 livers were purified. Type A1 livers contained a single isozyme with an atypical pH-rate profile; it was designated 22. Three isozymes were isolated from A2 livers, two of which corresponded to 11 and 22. A third, absent from the typical and the atypical A1 livers, had an intermediate mobility; it was designated 21. Type A1 livers are, therefore, the homozygous ADH2 2-2 phenotype, and type A2 livers, the heterozygous ADH2 2-1 phenotype. The ADH2 2-2 phenotype was found in 53% of 194 Japanese livers, and the ADH2 2-1 phenotype, in 31%. Accordingly, the frequency of ADH 2 2 was 0.68.This study was supported by U.S. Public Health Service Grant AA 02342.  相似文献   

3.
A novel syrup containing neofructo-oligosaccharides was produced from sucrose (Brix 70) by whole cells of Penicillium citrinum. The efficiency of fructo-oligosaccharides production was more than 55% and those of the main carbohydrate components, 1-kestose (Fruf 21Fruf 21 Glc), nystose (Fruf 21Fruf 21 Fruf 21 Glc) and neokestose (Fruf 26 Glc12 Fruf), were 22, 14 and 11%, respectively.  相似文献   

4.
Summary Suspensions of endocrine pancreas cells were prepared by shaking collagenase-isolated rat islets of Langerhans in calcium-free buffer. When incubated with 1.0 mM substrate at pH 7.4, the cells split,P i from 5-AMP at a rate of 87 nmol/h per g DNA, and from-glycerophosphate at a rate of 25 nmol/h per g DNAK m for 5 AMP was about 54 M. Adenosine or theophylline inhibited the 5-AMP hydrolysis. Homogenization of the cells increased the activity toward 5-AMP by 23% and that toward-glycerophosphate by 115%. Injecting rats with cortisone had no effect on the 5-AMP hydrolysis by whole cells but significantly increased the activity in cell homogenates; the intracellular activity toward 5-AMP was more than doubled by the cortisone treatment. Staining whole islet cells for 5-AMP-splitting activity resulted in a demarcation of the cell periphery in control rats. Cells from cortisone-treated rats showed heavier deposits of reaction product, and their cell periphery did not stand out as clearly. It is suggested that 5-nucleotidase is largely an ectoenzyme in normal rat islet cells. The cells also contain an as yet unidentified intracellular phosphatase that seems to be solely responsible for the increased hydrolysis of 5-AMP in cortisone-treated rats.  相似文献   

5.
Feulgen and silver-stained karyotypes and meiosis of two triploid viviparous onion forms (Allium cepa var.viviparum), the Croatian Ljutika and the Indian Pran, were comparatively analyzed. The results of chromosome measurements show that Ljutika and Pran are karyologically not identical, although significant similarities were found in the morphology of their chromosomes. Five geographically distant clones of Ljutika showed good agreement in the number and gross morphology of the chromosomes and in the number and position of NORs and interphase nucleoli. Heterotrivalents were predominant in meiosis of Ljutika but a relatively high frequency of higher multivalents together with univalents and bivalents were also observed. The relationship between Ljutika and Pran and their possible origin are discussed.  相似文献   

6.
The ability to produce extracellular O-glycosylhydrolases was studied in 14 strains of marine filamentous fungi sampled from the bottom sediments of the South China Sea. The following activities were detected in the culture liquids of the fungi: N-acetyl--D-glucosaminidase, -D-glucosidase, -D-galactosidase, -1,3-glucanase, amylase, and pustulanase. -1,3-Glucanases were isolated by ultrafiltration, hydrophobic interaction chromatography, and ion exchange chromatography, and their properties were studied. Data on products of enzymatic digestion of laminaran, absence of transglycosylation activity, and the pattern of action of natural inhibitors confirmed that -1,3-glucanase belonged to the exo type. Inhibitor analysis demonstrated the role of a thiol group and tryptophan and tyrosine residues in the catalytic activity.  相似文献   

7.
We study the improvement in timing accuracy in a neural system having n identical input neurons projecting to one target neuron. The n input neurons receive the same stimulus but fire at stochastic times selected from one of four specified probability densities, f, each with standard deviation 1.0 msec. The target cell fires if and when it receives m inputs within a time window of msec. Let n,m, denote the standard deviation of the time of firing of the target neuron (i.e. the standard deviation of the target neuron's latency relative to the arrival time of the stimulus). Mathematical analysis shows that n,m, is a very complicated function of n, m, and . Typically, n,m, is a non-monotone function of m and and the improvement of timing accuracy is highly dependent of the shape of the probability density for the time of firing of the input neurons. For appropriate choices of m, , and f, the standard deviation n,m, may be as low as . Thus, depending on these variables, remarkable improvements in timing accuracy of such a stochastic system may occur.  相似文献   

8.
In the present report, we used serological, cellular, and restriction fragment length polymorphism (RFLP) to investigate the DR1 haplotype in the Israeli population. We describe an Israeli homozygous typing cell (HTC), HLA-DwLVA, which defines a new lymphocyte-activating determinant associated with Bw65, DR1 and distinct from Dwl. The parents of this donor, non-Ashkenazi Algerian Jews, are first cousins and share HLA-Cw8, Bw65, BfS, DR1, DQw1, DPw4. No specificity could be assigned to HLA-DwLVA using the 91 Ninth Workshop HTCs. Two families and forty unrelated DR1 individuals were studied with DwLVA and a panel of DR1/Dw1 HTCs. HLA-DwLVA showed segregation as a single determinant within families. This new specificity was present in 24 out of 40 (60%) unrelated DR1 individuals, indicating that in the Israeli population DwLVA is the main lymphocyte-defined determinant associated with the serologically defined DRI specificity, in contrast to non-Jewish Caucasoids where DR1 is significantly associated with Dw1. The vast majority of DwLVA-positive carriers were also Bw65 carriers, indicating that Bw65, DR1, DwLVA may represent a typical allele combination in the Israeli population. The RFLP analysis established the correlation of certain RFLPs with Dw1 and DwLVA. In addition, we describe a cluster of RFLPs that may correspond to a new Dw subtype associated with DR1, for which no serological and cellular reagents have been described so far.  相似文献   

9.
Summary Soluble lead salts and a number of lead-containing minerals catalyze the formation of oligonucleotides from nucleoside 5-phosphorimidazolides. The effectiveness of lead compounds correlates strongly with their solubility. Under optimal conditions we were able to obtain 18% of pentamer and higher oligomers from ImpA. Reactions involving ImpU gave smaller yields.Abbreviations A adenosine - U uridine - Im imidazole - MeIm 1-methyl-imidazole - EDTA ethylenediaminetetraacetic acid - pA adenosine 5-phosphate - pU uridine 5-phosphate - Ap adenosine cyclic 2:3-phosphate - ATP adenosine 5-triphosphate - AppA P1,P2-diadenosine 5-diphosphate - pNp (N = A,U) nucleotide 2(3), 5-diphosphate - ImpA adenosine 5-phosphoreimidazolide - ImpU uridine 5-phosphorimidazolide - A 2pA adenylyl-[25]-adenosine - A 3pA adenylyl-[35]-adenosine - pA 2pA 5-phospho-adenylyl-[25]-adenosine - pA 3pA 5-phospho-adenylyl-[35]-adenosine - pUpU 5-phospho-uridylyl-uridine - pApU 5-phospho-adenylyl-uridine - pUpA 5-phospho-uridylyladenine - (pA)n (n, 2,3,4,) oligoadenylates with 5 terminal phosphate - ImpApA 5-phosphorimidazolide of adenylyl adenosine - (pA) 5+ pentamer and higher oligoadenylates with 5 terminal phosphate - (Ap)nA (n = 2,3,4) oligoadenylates without terminal phosphates In the following we do not specify the nature of the internucleotide linkageIn the following we do not specify the nature of the internucleotide linkage  相似文献   

10.
-Fructofuranosidase fromAspergillus japonicus, which produces 1-kestose (O--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) and nystose (O--d-fructofuranosyl-(21)--d-fructofuranosyl-(21)--d-fructofuranosyl -d-glucopyranoside) from sucrose, was purified to homogeneity by fractionation with calcium acetate and ammonium sulphate and chromatography with DEAE-Cellulofine and Sephadex G-200. Its molecular size was estimated to be about 304,000 Da by gel filtration. The enzyme was a glycoprotein which contained about 20% (w/w) carbohydrate. Optimum pH for the enzymatic reaction was 5.5 to 6. The enzyme was stable over a wide pH range, from pH 4 to 9. Optimum reaction temperature for the enzyme was 60 to 65°C and it was stable below 60°C. The Km value for sucrose was 0.21m. The enzyme was inhibited by metal ions, such as those of silver, lead and iron, and also byp-chloromercuribenzoate.  相似文献   

11.
Summary The histochemical activities of succinic dehydrogenase (SDH), myofibrillar Adenosine triphosphatase (ATPase) and alpha glycerophosphate dehydrogenase were studied in serial sections of rat vastus lateralis (red) (RVL), gastrocnemius and diaphragm muscles. Three main fibre-types were distinguished. The Type I fibres of RVL and gastrocnemius muscles fell into two distinct groups: one category-Type IA showed very low ATPase activity. The second category of Type IB fibres displayed moderate ATPase reaction. The Type IA fibres were divisible into two sub-groups when tested for SDH reaction. Type IA1 fibres possessed a homogenous distribution of diformazan·granules throughout the fibre: Type IA2 fibres displayed characteristic moth-eaten pattern of diformazan localization. The diaphragm muscle did not show either Type IB or Type IA2 varieties. The great majority of Type I fibres were sub-type IA1 in the three fast muscles studied. It is also demonstrated here that an inherent heterogeneity exists between Type I fibres of diaphragm and leg muscles in regard to -GPD localization. This histochemical data emphasizes the fact that subdivision of Type I striated muscle fibres of mammalian animals into two sub-types is only approximate and that a further subcategorization is possible.  相似文献   

12.
Biology cannot accommodate all aspects of culture. Aspects of culture that a biological approach can take into account can be covered by the biological categories of phenotype and environment. There is no need to treat culture as a separate category. Attempts to elaborate biological explanations of cultural variation will meet with success only if biologists expand theories of development, and integrate them in evolutionary biology. The alternative — elaborating the idea of so-called cultural inheritance — makes little sense from a biological point of view.  相似文献   

13.
The orientation behavior of walking flies, Drosophila melanogaster, towards a single 6° wide black vertical stripe (elementary stripe) can be explained by use of the turning tendency function H(). This function is characterized by maximal values at an angular distance of =25° from the stable zero position (=orienting direction), a sharp decline from this maximum to =60°, and a very slow approach to the unstable zero position (Horn and Wehner, 1975). The shape of this function is influenced by both translatory and rotatory components of movement. If the translatory component is minimized by measuring the turning function W() (see 2.3) at a distance of 10 mm (C1) from the center of the arena, a change in the strength of this decline is caused. But with increasing translatory component, i.e. at a greater distance from the center of the arena, W() approximates the heuristical function H() (Fig. 12). The turning functions W() are pattern-specific; the angular positions of the maximum responses shift to greater angles with increasing width of the patterns (Fig. 2). In the twopattern configuration with double or single stripes, there is always a coincidence between the stable zero positions of W (), the mean of the frequency distributions P() of the flies' positions and n g() of the straight courses, and the stable zero positions of H () obtained from an additive superposition of two or more angular shifted turning tendency functions H() (Fig. 5, 7). Therefore, the mean positions of the flies in a multi-stripe experiment composed of elementary stripes can be predicted from the addition of many angular shifted turning tendency functions H(). Between H() and the frequency distribution P() of the flies' positions , the following formula holds: P() =C·H()d (Fig. 13). With this equation, the spontaneous preference of the broader of two double stripes can be explained presuming lateral interactions between the components of the patterns (Fig. 8, 10). The strength x i * of this lateral interaction depends on the width of the double stripes. The greater , the smaller is x i * . x i * is a pattern-specific value (Table 1, 2).Supported by the Deutsche Forschungsgemeinschaft, Ho 664/2  相似文献   

14.
We have developed a new method for the large scale preparation of pyridylaminated (PA-) oligosaccharides from glycoproteins. Phenol/chloroform extration was adapted for the removal of protein and excess 2-aminopyridine, improving the efficiency of preparation. From a 2.5 g sample of human apo-transferrin, 25–30 mol of agalacto biantennary PA-oligosaccharide could be obtained. By increasing the concentration of PA-oligosaccharide substrate, we were able to detect a very low level ofN-acetylglucosaminlytransferase IV activity in CHO cell extracts.Abbreviations PA 2-aminopyridine - SDS sodium dodecyl sulfate - GlcNAc N-acetylglucosamine - GnT N-acetylglucosaminyltransferase - Gn,Gn-bi-PA GlcNAc1-2Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine - Gn,Gn,Gn-tri-PA GlcNAc1-2(GlcNAc1-4)Man1-3(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine - Gn,Gn,Gn-trí-PA GlcNAc1-2Man1-3({GlcNAc1-2(GlcNAc1-6)Man1-6})Man1-4GlcNac1-4GlcNAc-2-aminopyridine - Gn,(Gn),Gn-bi-PA GlcNAc1-2Man1-3(GlcNAc1-4)(GlcNAc1-2Man1-6)Man1-4GlcNAc1-4GlcNAc-2-aminopyridine  相似文献   

15.
Anthocyanins isolated and characterized from the wild carrot suspension cultures used here were 3-O--D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D<-galactopyranosylcyanidin (1), 3-O-[-D- xylopyranosyl-(12)--D-galactopyranosyl]cyanidin (2), 3-O-(6-O-sinapoyl)--D-glucopyranosyl-(16)-[-D- xylopyranosyl-(12)-]-D-galactopyranos ylcyanidin (3), 3-O-(6-O-feruoyl)--D-glucopyranosyl-(16)-[- D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (4), 3-O-(6-O-coumaroyl)--D-glucopyranosyl-(16)- [-D-xylopyranosyl-(12)-]-D-galactopyrano sylcyanidin (5), 3-O-[6-O-(3,4,5-trimethoxycinnamoyl)]-- D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (6), 3-O-[6-O-(3,4-dime- thoxycinnamoyl)]--D-glucopyranosyl-(16)-[-D-xylopyranosyl-(12)-]-D-galactopyranosylcyanidin (7), 3-O-[(6-O-sinapoyl)--D-glucopyranosyl-(16)--D-galactopyranosyl]cyanidin (8), and 3-O-(-D-galactopyranosyl)cyanidin (9). Except when cinnamic acids were provided in the culture medium, the major anthocyanin present in the two clones examined was 2. When the naturally occurring and some non-naturally occurring cinnamic acids were provided individually in the medium, 1 and 2 were minor components and the anthocyanin acylated with the supplied cinnamic acid, namely 3, 4, 5, 6, or 7 was the major anthocyanin present in the tissue. When caffeic acid was provided the major anthocyanin in the tissue was 4, thereby suggesting that the caffeic acid was methylated before its use in anthocyanin biosynthesis. Other cinnamic acids supplied had limited effects on the anthocyanins accumulated and appeared not to result in the accumulation of new anthocyanins by the tissue. Thus the tissue can use some but not all analogues of sinapic acid to acylate anthocyanins. Additional anthocyanins were detected in extracts of the wild carrot tissue cultures using mass spectrometry (both MS/MS and HPLC/MS). The additional compounds detected have also been found in cultures of black carrot, an Afghan cultivar of Daucus carota ssp. sativa and the flowers of wild carrot giving no evidence for qualitative differences in the anthocyanins synthesized by subspecies, cell cultures from subspecies, or clones from cell cultures. There are major differences in the amounts of individual anthocyanins found in cultures from different subspecies and in different clones from cell cultures. Here anthocyanins without acyl groups were usually found in the tissues and their accumulation is discussed. On the basis of the structures of the isolated anthocyanins, a likely pathway from cyanidin to the accumulated anthocyanins is proposed and discussed.Abbreviations Sin sinapoyl - Fer feruoyl - 4-Coum. 4-coumaroyl - 3,4-MeO2Cin 3,4-dimethoxyeinnamoyl - 3,4,5-MeO3Cin 3,4,5-trimethoxycinnamoyl - Cya cyanidin  相似文献   

16.
Two intracellular -glucosidases (E.C. 3.2.1.21) were purified from the filamentous fungus Neurospora crassa, mutant cell-1 (FGSC no. 4335) and characterized. The extent of purification were 2.55- and 28.89-fold for -glucosidase A and -glucosidase B, respectively. -Glucosidase A was a dimeric protein, and B a monomeric protein, with molecular masses of 178 and 106 kDa, respectively. Both isoenzymes were glycoproteins with relatively high carbohydrate contents (-glucosidase A, 29.2%; -glucosidase B, 34.2%). The isoelectric points determined by IEF were 6.27 and 4.72, respectively. pH optima for activity were determined to be 5.0 and 5.5, and temperature optima to be 55 and 60 °C, for -glucosidases A and B, respectively. Both purified -glucosidases. especially -glucosidase B, showed relatively high stability against pH and temperature. Both enzymes were stable in the pH range of 5.0–9.0. The activities were completely retained up to 48 h at temperatures below 40 °C. At higher temperatures, enzymes were relatively unstable and lost their activities at 60 °C after 24 h. Both -glucosidases were highly activated by CuCl2, and inhibited by SnCl2 and KMnO4. Hg2+ and Ag+ also inhibited severely -glucosidase B. The K m and V max values of the isoenzymes against cellobiose as substrate were 1.50 mM and 12.2mol min–1 mg–1 for -glucosidase A and 2.76 mM and 143.5 mol min–1 mg–1 for -glucosidase B.  相似文献   

17.
Zeins from Zea mays L cv. Maya and coixins from Coix lacryma-jobi L. cv. Adlay were fractionated to obtain -, -, and -zein and -, -, and -coixin. The -coixins were composed of 4 polypeptide classes of 27 kDa (C1), 25 kDa (C2), 17 kDa (C4) and 15 kDa (C5) with solubility properties very similar to those of the 22 kDa and 19 kDa -zeins. Like the -zeins, the C1 and C2 -coixins corresponded to 80% of total Coix prolamins. The fraction corresponding to -coixin contained only one protein band of 22 kDa (C3). This coixin fraction has solubility properties similar to those of -zein and represents 15% of the total coixin. The -zein fraction was composed of a major 17 kDa protein band, while the -coixin fraction consisted of a mixture of - and -coixins.Polyclonal antibodies raised against C1 recognized C1 and C2 and cross-reacted strongly with the 22 kDa -zein, as did C4 and C5 antisera. The antiserum against -coixin showed strong cross-reaction with -zein. The homology between coixins and zeins was further investigated by using Southern hybridization analyses. The genomic DNA of maize and Coix were digested with several restriction enzymes and probed with cDNA clones representing 19 and 22 kDa -zeins as well as the 28 and 16 kDa -zeins. The Coix genome showed complex cross-hybridization sequences with the 22 kDa -zein cDNA, while no cross-hybridization was observed with the 19 kDa cDNA clone. The cDNA clone representing the 28 kDa -zein cross-hybridized with only one band of Coix genomic DNA, in contrast to the three bands observed in maize. This same Coix sequence also cross-hybridized with the cDNA clone representing the 16 kDa -zein. The relevance of these findings are discussed in the context of the origin of zein and coixin genes.  相似文献   

18.
Summary The pathogenFusarium solani sensuSnyder &Hansen, as identified byW. L. Gordon was recorded in the present work as a new species causing cotton wilt in Egypt. Cotton dust in varying concentrations does not significally alter the normal infection of both Menoufi and Giza 26 cotton varieties towardsFusarium. Similarly the potency ofFusarium filtrate to induce wilting did not appreciably change with previous treatment of cotton plants with cotton dust. On the other hand leaves treated with 2,4-D showed the maximal water loss. Percentage infected Giza 26 cotton seedlings were found to be comparatively less in soil infected with 2,4-D treatedFusarium mycelium than in that infected with untreated mycelium.  相似文献   

19.
Zusammenfassung In den Jahren 1961 und 1962 wurden Untersuchungen mit Hilfe der Exosmose-Methode durchgeführt, um sich über die Frostresistenz von nahezu 100 Apfelsorten zu orientieren. Die Versuchsergebnisse (ausgedrückt in RLF-Werten, d. h. als Proportion des elektrolytischen Widerstandes zwischen den Kontrollen und den kältebehandelten Pflanzenteilen) zeigen gute Übereinstimmung mit den Resultaten anderer Härtebeurteilungsmethoden, z. B. mit den Gefrierversuchen in Gefrierkammern und mit den amerikanischen, deutschen und schweidischen Freilandbeobachtungen. Die berechneten Korrelationskoeffizienten gaben Werte von r=>+0,750 mit einer statistischen Sicherheit von P=<0,001. Es gibt jedoch Sorten, welche sich unter den verschiedenen Versuchsbedingungen nicht gleichartig verhielten. In diese Gruppe gehören die Sorten Goldparmäne, James Grieve, Lanes Prince Albert, Schöner aus Nordhausen, Slava Petersburga und Transparente de Croncels. Der Zusammenhang zwischen der geographischen Herkunft und der Frostresistenz ist augenfällig. Die durchschnittlichen RLF-Werte der frostempfindlichen oder sehr frostempfindlichen französischen Sorten liegen bei ungefähr 150, die der finnischen und baltischen frostharten Sorten dagegen unter 110. Die Rangordnung der verschiedenen Klimagebiete erfolgte entsprechend der geographischen Lage. Es gab Sorten, die der allgemeinen Tendenz nicht folgten und sich abweichend verhielten. Hierzu gehören: Transparente de Croncels, (Frankreich), Wealthy (USA), Cox Pomona und Ribston (Großbritannien). Über eine wesentlich schlechtere Resistenz, als auf Grund des Ursprungsgebietes zu erwarten war, verfügt Ontario (Kanada).  相似文献   

20.
Four glycosidases were analyzed in 10 mm apical segments prepared from growing roots (15 mm) of Zea mays L. The pH optima were found to be 5.8 for -glucosidase, 4.4 for -galactosidase, 6.4 for -glucosidase and 6.0 for -galactosidase. The -glucosidase showed 4-fold higher activity than the -galactosidase. The distribution of the -glucosidase activity was signifcantly different from that of the -galactosidase, -glucosidase and -galactosidase.Abbreviations -Glu -glucosidase - -Gal -galactosidase - -Glu -glucosidase - -Gal -galactosidase  相似文献   

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