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11.
Qiuping Ran Mengtian Huang Huanan Li Bixin Chen Lili He Xinxin Cui Jiashu Liu Zhengbing Jiang 《Global Change Biology Bioenergy》2023,15(6):821-833
In the process of bioethanol production, more stable and active cellulase in high temperature condition is required. In this study, syringic acid was applied in cellulase hydrolysis system. At 70°C, TvEG3 activity increased 201.36%, CtBglA activity decreased 72.79% by syringic acid. With syringic acid assisting, TvEG3 thermostability was improved, CtBglA thermostability was reduced. Syringic acid scarcely affected CtCBH. In hydrolysis system with the cellulases containing TvEG3, CtCBH, and CtBglA, the reducing sugar yield improved by 28.37% with syringic acid assisting. With the molecular dynamic simulation in syringic acid system, the backbone root-mean-square deviation (RMSD) and the residue root-mean-square fluctuation (RMSF) of TvEG3, CtCBH reduced, while the RMSD and RMSF of CtBglA increased. The reduction in the number of secondary structures, especially α-helix, caused the structure of CtBglA in the presence of syringic acid to collapse at high temperature. More secondary structures in TvEG3 and more α-helix in CtCBH in the presence of syringic acid make them more stable at high temperatures. These means syringic acid can stabilize TvEG3 and CtCBH structure, destabilize CtBglA structure at high temperature. In summary, this study not only provides insight into cellulase hydrolysis at high temperature with syringic acid assisting but also demonstrates the promoting mechanism of syringic acid. 相似文献
12.
为探究燕麦(Avena sativa)-绿豆(Phaseolus radiatus)间作效应及氮素转移特性, 在不施氮肥的大田试验条件下, 设置3种种植模式(燕麦单作、绿豆单作和燕麦-绿豆间作), 采用传统挖根法和15N同位素标记法进行研究。结果表明, 间作系统中燕麦侵袭力强于绿豆, 绿豆生长受到抑制。整个生育期, 间作燕麦地上部干物质积累量比单作增加14.9%-33.1%, 2年成熟期间作燕麦的氮素积累量比单作分别提高53.1%和44.8%; 间作减少了开花结荚期绿豆氮素积累量和根瘤重量, 降低了绿豆的固氮效率, 绿豆的固氮效率2年平均降低23.7%, 生物固氮量平均减少11.66%。间作绿豆向燕麦的氮素转移率2年平均值达31.7%, 氮素转移量为212.16 kg∙hm-2。燕麦-绿豆间作降低了开花结荚期绿豆的根瘤固氮酶活性和固氮效率, 但绿豆体内氮素转移增加了燕麦对氮素的吸收利用, 实现了地上部与地下部生长的相互调节和促进, 优化了农田生态系统的氮素管理。 相似文献
13.
Lili Bao Le Deng Lihua Nie Shouzhuo Yao Wanzhi Wei 《Biosensors & bioelectronics》1996,11(12):1193-1198
A rapid method for microorganism detection using a piezoelectric quartz crystal sensor (PQC) coated with a thin liquid culture medium film was developed and applied to detect the cell number of Proteus vulgaris. This method employed the viscosity and density response of PQC and utilized the coagulation of gelatine medium solution in which the microorganisms had grown to determine the microorganism indirectly. Three time points (TT1, DT, TT2) were obtained from the coagulation curve and were found to be in good linear relationship with the logarithm of the initial number of P. vulgaris in the range 1·3 × 102−1·3 × 105 cells/ml. The detection was rapid and accurate because the coagulation of the thin liquid culture medium film was quick and the time points in the response curve were sharp and so were easy to determine accurately. The detection time was less than 4 h and only a micro sample was needed. A 5 h preincubation was needed before detection. Some experimental conditions are discussed in detail. 相似文献
14.
朱砂叶螨羧酸脂酶最优测试条件的选择 总被引:1,自引:0,他引:1
应用二次回归通用旋转组合设计,对朱砂叶螨离体羧酸酯酶测试过程中所需缓冲液pH值、恒温时间、反应温度及底物浓度,设立4因子5水平试验,在考虑4个因子主效应和互作效应的情况下,筛选测试羧酸酯酶的最优条件组合。 相似文献
15.
用快速微量等电聚焦技术对190名北京地区汉族健康人血清Gc蛋白亚型、Pi蛋白亚型进行分型鉴定和基因频率调查.上样量为1.5μl,电泳和染色各0.5h.Gc1F=0.4891,Gc1S=0.2432,Gc2=0.2678.观察值与期望值吻合良好.(∑X2=1.404,0.7<P<0.8).PiM1=0.7542,PiM2=0.1808,PiM3=0.0650,观察值与期望值吻合也良好,(∑X2=1.1233,0.7<P<0.8). 相似文献
16.
The lack of physical mapping data strongly restricts the analysis of the meningioma chromosomal region that was assigned to the bands 22q12.3-qter. Recently, we reported a new marker D22S16 for chromosome 22 that was assigned to the region 22q13-qter by in situ hybridization. Utilizing somatic cell hybrids we now sublocalized the marker D22S16 within the band region 22q12-13.1, thus placing it in the vicinity of the gene for the platelet derived growth factor (PDGFB). A physical map was established for the regions surrounding the PDGFB gene and the D22S16 marker. By means of pulsed-field gel electrophoresis (PFGE) D22S16 and PDGFB were found to be physically linked within 900 kb. We also identified two CpG clusters bordering the PDGFB gene. For the enzyme NotI, a variation of the PDGFB restriction pattern was found between different individuals. PFGE analysis of the two loci (PDFGB and D22S16) failed to identify major rearrangements in meningioma. 相似文献
17.
Summary The spatial relationships between the homologous pairs of chromosomes in the normal human colcemid-treated metaphase plate were tested by two different mathematical approaches: (a) determination of the distances between the centromeres of the homologous chromosomes compared to the mean distance of all centromeres of the mitosis in question; (b) measuring the distances of the different chromosomes from the center of the mitosis.The following results were obtained: (1) The arrangement of human metaphase chromosomes does not follow a normal distribution; the distribution is narrower and taller, probably due to an impairment of free chromosome spreading by the cell membrane. We believe that only in membraneless mitotic cells should the chromosome-spread correspond to a normal distribution under the same preparation conditions. (2) There is a positive correlation between decreasing chromosome size and decreasing mean distance between homologous chromosomes. (3) A close positive correlation exists between increasing chromosome size and increasing distance to the barycenter of the mitosis. (4) There is also a close positive correlation between the distance of homologous chromosome pairs and their distance from the center of the mitosis, i.e., with increasing distance from the center of the mitosis, the distance between the homologous partners increases. (5) The following statistically significant deviations from these rules could be established: (a) The large acrocentric chromosomes are closer associated, as one would expect from their size, probably due to their participation in the nucleolus organization; (b) in the female cell one of the two X chromosomes has an extremely peripheral localization; the X chromosomes are furthest apart of all pairs of homologous chromosomes; (c) the chromosome pairs 6 and 8 are relatively close together in spite of their peripheral position, suggesting a truc close association of the homologus partners; (d) the chromosome pair 18 has a more peripheral position than expected, and a relatively large mean distance between the homologous partners; (e) the chromosome pair 1 has a much more central position and a closer association than is expected from its size. 相似文献
18.
Herwig Zang 《Journal of Ornithology》1980,121(4):371-386
Zusammenfassung 1969–1977 wurden in 15 Untersuchungsgebieten des Harzes, die sich auf die Höhenstufen von 100–900 m verteilen, brutbiologische Daten bei Trauerschnäpper, Sumpf-, Blau-, Kohl- und Tannenmeise gesammelt.Die Siedlungsdichte nimmt jeweils auf die Hälfte ab bei einer Höhenzunahme für die Sumpfmeise von 270 m, die Kohlmeise 195 m, die Tannenmeise 178 m und die Blaumeise 101 m (Halbwertshöhe).Die Verzögerung des Legebeginns bzw. des Schlüpftermins beträgt beim Trauerschnäpper 1,72, bei der Tannenmeise 1,68, der Sumpfmeise 1,97, der Kohlmeise 2,19 und der Blaumeise 5,24 Tage/100 m parallel zur vertikalen Verzögerung der Vegetationsentwicklung (Phänologie) von 1,8–2,6 Tage/100 m.Die Gelegegröße von Trauerschnäpper, Sumpf-, Blau- und Kohlmeise nimmt mit zunehmender Höhe linear um 0,14; 0,52; 0,51; und 0,11 Eier/100 m ab. Für die Kohlmeise ergeben sich Unterschiede in Laub- und Nadelwald, für die Tannenmeise zeigt sich eine Tendenz zur Zunahme mit der Höhe.Die Abnahme des Bruterfolges mit der Höhe beträgt beim Trauerschnäpper 0,22 flügge Junge/100 m, bei der Blaumeise 0,57, der Sumpfmeise 0,37, der Tannenmeise 0,23 und der Kohlmeise 0,13 flügge Junge/100 m. Für die Kohlmeise ergeben sich auch hier wieder Unterschiede in Laub- und Nadelwald.Für die Tannenmeise nimmt der Zweibrutanteil mit zunehmender Höhe linear um 3,6 %/100 m ab. Für die Kohlmeise zeigt er ebenfalls fallende Tendenz.Definiert man als vertikale Verbreitungsgrenze einer Art die Höhe, in der sich eine Population im Mittel noch stabil erhalten kann, so lassen sich aus der ermittelten Abnahme des Bruterfolges und den Werten für die Überlebensrate in einer vereinfachten Modellrechnung folgende Grenzen im Harz ermitteln: Blaumeise 500 m, Sumpfmeise 700 m, Kohlmeise 950 m, Trauerschnäpper und Tannenmeise 1000 m. Dies stimmt gut mit der Erfahrung überein.
The altitudinal influence on the population density and on the breeding biology ofFicedula hypoleuca, Parus palustris, P. caeruleus, P. major andP. ater in the Harz Mountains
Summary (a) Between 1967 and 1977, biological breeding data ofFicedula hypoleuca, Parus palustris, P. caeruleus, P. major andP. ater have been collected in 15 study areas of the Harz mountains, at altitude ranging from 100 m to 900 m.(b) The population density decreases by half, as a result of an increase in altitude of 270 m inP. palustris, 195 m inP. major, 178 m inP. ater and 101 m inP. caeruleus (halfvalue altitude).(c) The beginning of egglaying or hatching is delayed by 1.72 days per 100 m inFicedula hypoleuca; 1.68 days inP. ater; 1.97 days inP. palustris; 2.19 days inP. major and 5.24 days inP. caeruleus. These altitudinal retardations are parallel to that of the environmental vegetation (phenology) of 1.8–2.6 days per 100 m.(d) The clutch-size ofFicedula hypoleuca, P. palustris, P. caeruleus andP. major decreases by 0.14; 0.52; 0.51 and 0.11 eggs per 100 m increase of altitude respectively. InP. major, variations occur between deciduous and coniferous forests, and inP. ater the clutch-size tends to increase with an altitudinal increase.(e) The decrease in breeding success amounts to 0.22 fledglings per 100 m increase of altitude inFicedula hypoleuca, 0.57 fledglings inP. caeruleus, 0.37 fledglings inP. palustris, 0.23 fledglings inP. ater and 0.13 fledglings inP. major. Again, in the case ofP. major, differences occur between deciduous and coniferous forests.(f) The percentage of second broods ofP. ater decreases by 3.6 % per 100 m increase of altitude. The percentage of second broods ofP. major shows decreasing tendency, too.(g) When the altitudinal distribution limit of a species is defined as the level at which a population remains stable, the altitudinal decrease of breeding success and the mortality permit to draw up a simplified table of the altitudinal distribution limit. In the Harz these limits are as follows:P. caeruleus 500 m,P. palustris 700 m,P. major 950 m,F. hypoleuca 1000 m, andP. ater 1000 m. These results coincide with the experience.相似文献
19.
Summary The pattern of association of acrocentric chromosomes was examined in ten and five carriers of a 15/21 and a 13/14 Robertsonian translocation, respectively, and was compared with that of the same numbers of relatives with normal karyotypes. In the carriers of 15/21 translocation, the number of large associations (involving more than two acrocentrics) and the association frequencies for individual acrocentric chromosomes, were significantly higher than in the control group. The mean number of associations of the single homologs of the translocation chromosomes was much higher than that of the other acrocentrics. In the carriers of 13/14 translocations, only the association frequency for chromosome 13 was higher than in the normal relatives. The uninvolved chromosomes homologous to those involved in translocations showed an insignificant increase in associations in comparison with the other acrocentrics. These results suggest that some mechanism within the cells compensates for the effect of missing acrocentrics or of acrocentrics lacking NORs on the number of associations. The possible relations of this phenomenon to the activity of the nucleolus organizing regions are discussed. 相似文献
20.
Twelve out of 88 cytogenetically examined meningiomas of female patients showed, in addition to the typical loss of a chromosome 22, a loss of 1 or more chromosomes of group C. Among them 8 tumors had less than 8% cells with Barr-body-like particles, whereas in one tumor 12% and in 3 others over 20% Barr bodies were found, which, based on control studies, were classified as sex-chromatin negative, partly positive, and positive, respectively. In one case the loss of an X chromosome was verified by Giemsa banding. In 6 out of 24 meningiomas of male origin, the chromosomal morphology and association pattern strongly indicated that besides the loss of a chromosome 22, the Y chromosome was also missing. Moreover, the loss of the male sex chromosome could be ascertained in 4 tumors by the conspicuous absence of Y fluorescence in interphase nuclei and in metaphase plates after fluorescence staining. The findings are discussed in connection with the gonosomal loss in other human tumors and in old age. 相似文献