两株聚球藻伴生细菌分离纯化与促生功能鉴定

【背景】蓝藻周围存在伴生细菌,伴生细菌与蓝藻具有复杂的作用关系。【目的】研究淡水聚球藻伴生细菌对聚球藻生长的影响。【方法】采用高通量测序分析聚球藻伴生细菌多样性;平板划线法纯化聚球藻伴生细菌,通过形态观察结合16S rRNA基因序列同源性比对,对其种属关系进行确定;通过聚球藻和不同浓度伴生细菌共培养测定其叶绿素a浓度,分析伴生细菌对聚球藻生长的影响;采用种子发芽试验验证伴生细菌促生功能。【结果】淡水聚球藻伴生细菌优势菌属为产卟啉杆菌属(Porphyrobacter)、根瘤菌属(Rhizobium)、水单胞菌属(Aquimonas)和中慢生根瘤菌属(Mesorhizobium),从聚球藻分离获得了两株伴生细菌JQ1和JQ2,基于16S rRNA基因序列鉴定其分别属于Rhizobium和Peribacillus,通过在聚球藻与不同浓度伴生细菌共培养及水稻发芽试验验证,证明伴生细菌JQ1和JQ2在菌藻比例分别为5:1和15:1时具有促生作用,都对增强秧苗素质和根系发育有一定影响但JQ2与JQ1相比能显著提高水稻种子的发芽率。【结论】淡水聚球藻伴生细菌JQ1和JQ2在适宜的浓度均可显著促进聚球...     

Titles of related papers in other sections

Previous results have shown that the autoantibody eluted from the glomeruli of rats with active Heymann nephritis contain a population of antibodies not only to the putative autoantigen of the disease, gp330, but alos to plasminogen. Since gp330 has been shown to serve as a receptor for plasminogen, we have analyzed the effects of autoantibody on plasminogen-binding to gp330 and activation of plasminogen to plasmin by urokinase. Autoantibody does not inhibit the binding of plasminogen to gp330. The change in the conformation of plasminogen when its lysine-binding sites are occupied or after conversion to plasmin results in a significant decrease in autoantibody-binding. The most significant effect of autoantibody on this system is the inhibition of plasminogen activation to plasmin by urokinase. The binding of autoantibody to plasminogen acts as a competitive inhibitor of the reaction by apparently blocking access of urokinase to plasminogen's activation site. These results indicate that autoantibody obtained from the immune deposits in the glomeruli of rats with active Heyman nephritis does not inhibit the binding of plasminogen to gp330 but does significantly alter the urokinase catalyzed activation of plasminogen to plasmin.     

Responses of alfalfa pollen and callus to filtrates from two isolates of Fusarium oxysporum

Summary For 25 Medicago sativa plants, measurements were made of in vitro pollen germination and growth and callus growth on mediums containing culture filtrate from two isolates of Fusarium oxysporum f. sp. medicaginis. In vivo resistance was determined by field inoculation with one isolate. There was no correlation between any in vitro measurement and in vivo resistance, and none of the in vitro measurements on control mediums were correlated. The only significant correlation for the same measurement between the two isolates was for pollen-tube length (r = 0.65). Percent of pollen germination was negatively correlated with callus growth for both isolates. Earlier work showed that callus growth in the presence of culture filtrate was linked to plant resistance, thus it appeared that percent pollen germination on culture filtrate had decreased for the more resistant plants. The haploid pollen may be used as a progeny test for identifying heterotic loci conferring resistance to Fusarium, but if the pollen of this plant species is used in direct selection by exposure to culture filtrate, the level of resistance to Fusarium may decrease.     

盐磷胁迫对木麻黄和台湾相思种子萌发及幼苗生长的影响

恶劣环境下,人工海防林因面临养分胁迫而经营困难。为探讨盐、磷胁迫对主要海防林树种木麻黄和台湾相思种子萌发及生长的影响,该研究分别用不同浓度的NaCl(盐)和KH₂PO₄(磷)溶液处理种子和浇灌幼苗,测定种子萌发和幼苗生长指标。结果表明：(1)高盐胁迫显著抑制种子萌发,对幼苗生长有一定影响,但两种植物影响程度不同;台湾相思种子萌发耐盐性高于木麻黄,前者相对盐害率最大值为23.03%,后者为89.15%;随着盐浓度增加,木麻黄和台湾相思种子的发芽率、发芽势、发芽指数和活力指数均降低,对应最大值分别为38.70%、34.67%、18.70、0.055和76.67%、62.22%、48.46、6.11。(2)两种植物的株高和根长随盐浓度增加而降低,木麻黄和台湾相思株高分别为12.29～6.01 mm和48.27～17.33 mm,根长分别为8.57～1.45 mm和33.41～5.88 mm;台湾相思根、茎、叶生物量及根冠比均随盐浓度的增加逐渐减小,木麻黄各处理差异较小。(3)台湾相思的种子和幼苗较木麻黄更耐低磷环境,二者最适磷浓度存在差异;木麻黄种...     

Root traits of perennial C4 grasses contribute to cultivar variations in soil chemistry and species patterns in particulate and mineral-associated carbon pool formation

Recent studies have indicated that the C₄ perennial bioenergy crops switchgrass (Panicum virgatum) and big bluestem (Andropogon gerardii) accumulate significant amounts of soil carbon (C) owing to their extensive root systems. Soil C accumulation is likely driven by inter- and intraspecific variability in plant traits, but the mechanisms that underpin this variability remain unresolved. In this study we evaluated how inter- and intraspecific variation in root traits of cultivars from switchgrass (Cave-in-Rock, Kanlow, Southlow) and big bluestem (Bonanza, Southlow, Suther) affected the associations of soil C accumulation across soil fractions using stable isotope techniques. Our experimental field site was established in June 2008 at Fermilab in Batavia, IL. In 2018, soil cores were collected (30 cm depth) from all cultivars. We measured root biomass, root diameter, specific root length, bulk soil C, C associated with coarse particulate organic matter (CPOM) and fine particulate organic matter plus silt- and clay-sized fractions, and characterized organic matter chemical class composition in soil using high-resolution Fourier-transform ion cyclotron resonance mass spectrometry. C₄ species were established on soils that supported C₃ grassland for 36 years before planting, which allowed us to use differences in the natural abundance of stable C isotopes to quantify C₄ plant-derived C. We found that big bluestem had 36.9% higher C₄ plant-derived C compared to switchgrass in the CPOM fraction in the 0–10 cm depth, while switchgrass had 60.7% higher C₄ plant-derived C compared to big bluestem in the clay fraction in the 10–20 cm depth. Our findings suggest that the large root system in big bluestem helps increase POM-C formation quickly, while switchgrass root structure and chemistry build a mineral-bound clay C pool through time. Thus, both species and cultivar selection can help improve bioenergy management to maximize soil carbon gains and lower CO₂ emissions.     

血清SIRT1水平与射血分数保留的心力衰竭患者炎性因子、氧化应激的相关性分析及对预后的影响研究

摘要 目的：探讨血清去乙酰化酶1（SIRT1） 水平与射血分数保留的心力衰竭（HFpEF）患者炎性因子、氧化应激的相关性,分析SIRT1预测HFpEF患者预后的价值。方法：选择2019年10月至2021年6月青岛阜外心血管病医院收治的190例HFpEF患者为HFpEF组,92例心功能正常的健康体检志愿者为对照组。HFpEF患者出院后随访12个月,统计随访期间不良心血管事件发生情况,多因素Logistic回归分析HFpEF患者预后不良的影响因素。结果：HFpEF组血清SIRT1水平低于对照组（P＜0.05）,白细胞介素（IL）-6、肿瘤坏死因子-α（TNF-α）、C反应蛋白（CRP）、丙二醛（MDA）、晚期氧化蛋白产物（AOPP）水平高于对照组（P＜0.05）。HFpEF患者血清SIRT1水平与IL-6、TNF-α、CRP、MDA、AOPP呈负相关（r=-0.496、-0.502、-0.419、-0.533、-0.542,P＜0.05）。190例患者2例失访,余188例HFpEF患者中41例预后不良,147例预后良好。预后不良组美国纽约心脏病协会（NYHA）Ⅳ级比例、IL-6、TNF-α、CRP、MDA、AOPP、N末端B型利钠肽前体（NT-proBNP）水平、左室收缩末期内径（LVEDS）、左室舒张末期内径（LVEDD）、二尖瓣舒张早期血流峰值（E）与舒张晚期血流峰值（A）（E/A）高于预后良好组（P＜0.05）,血清SIRT1水平、左心室射血分数（LVEF）低于预后良好组（P＜0.05）。高IL-6、高MDA、高NT-proBNP是HFpEF患者预后不良的危险因素（P＜0.05）,SIRT1是HFpEF患者预后不良的保护因素（P＜0.05）。结论：HFpEF患者血清SIRT1水平降低,与HFpEF患者炎症反应、氧化应激以及预后不良的发生有关,可作为HFpEF患者预后评估的辅助指标。     

Changes in protein synthesis during stratification and dormancy release in embryos of sugar maple (Acer saccharum)

Protein synthesis in dormant embryos of sugar maple ( Acer saccharum ) was investigated in seeds stratified at 4°C or incubated at 15°C. Seeds stratified at 4°C germinated after 27 days; seeds incubated at 15°C failed to germinate. Stratification increased the embryo's capacity for protein synthesis by day 11 as measured by in vivo incorporation of [³⁵S]-methionine into purified protein. At 4°C protein synthesis in the embryonic axis rose in a linear fashion prior to germination, whereas in cotyledons it increased until day 20 and then declined. Analysis of radiolabelled proteins by two-dimensional gel electrophoresis revealed that the levels of specific proteins were altered by temperature, primarily in the cotyledons. Several proteins were expressed in the cotyledons at 15°C but were absent in unstratified embryos and in embryos stratified at 4°C. That is, the expression of these proteins was repressed during stratification and release from dormancy. Levels of other proteins in the cotyledons declined at 4°C during stratification. We suggest that one or more of these proteins may be associated with the inhibition of growth of the embryonic axis imposed by the cotyledons.     

LIFE-CYCLE COMPONENTS OF SELECTION IN ERIGERON ANNUUS: II. GENETIC VARIATION

Genetic variation for seedling and adult fitness components was measured under natural conditions to determine the relative importance of the seedling stage for lifetime fitness in Erigeron annuus. Variation in lifetime reproductive success can result from both the persistent effects of genetic variation expressed among seedlings and from variation in adult fitness components. Analysis of covariance was used to separate the stage specific from the cumulative effects of genetic variance expressed earlier in the life cycle. E. annuus produces seeds through apomixis, which allowed measurement of the fitness of replicate genotypes from germination through the entire life cycle. There were significant differences among genotypes for date of emergence, seedling size, survivorship and fecundity, but heritabilities were low, indicating slow response to selection. For all characters, environmental components of variance were one to two orders of magnitude larger than genetic variance components, resulting in broad sense heritabilities less than 0.1. For seedling size and fecundity, all of the genetic variance was in the form of genotype-environment interactions, often with large negative genetic correlations across environments. In contrast, genotypes differed in mean survivorship through one year, but there were no genotype-environment interactions for viability. Genetic differences in viability were primarily expressed as differences in overwinter survivorship. Genotype × environment interactions among sites and blocks were generated early in the life cycle while the genotype × environment interactions in response to competitive environment (open, annual cover, perennial cover) first appeared in adult fecundity. Genetic variation in lifetime fitness was not significant, despite a fourfold difference in mean fitness among genotypes.     

β-Glucosidase activities and HCN liberation in unimbibed and imbibed seeds, and the induction of cocklebur seed germination by cyanogenic glycosides

In many seed species, the major source of HCN evolved during water imbibition is cyanogenic glycosides. The present investigation was performed to elucidate the role of endogenous cyanogenic glycosides in the control of seed germination and to examine the involvment of β-glucosidase in this process. All seed species used here contained some activities of β-glucosidase already in the dry state before imbibition. in the decreasing order of Malus pumila, Daucus carota, Hordeum vulgare, Chenopodium album and so on. β-Gluosidase activity in upper and lower seeds of cocklebur (Xanthium pennsylvanicum Wallr.) decreased with imbibition, and in lower seeds the activity disappeared when they germinated. On the contrary, in caryopses of rice (Oryza sativa L. cv. Sasanishiki) β-glucosidase increased during imbibition, and this increase continued even after germination. β-Glucosidase in cocklebur seeds was more active in the axial than in the cotyledonary tissue. Amygdalin, prunasin and linamarin could all serve as substrattes for the β-glucosidase(s) from both cocklebur and rice. Amygdalin, prunasin and linamarin as well as KCN, were effective in stimulating the germination of upper cocklebur seeds. The seeds evolved much more free HCN gas when they were exposed to the cyanogenic glycosides than when the glycosides were absent. Moreover, the application of the cyanogenic glycosides or of KCN caused accumulation of bound HCN in the seeds. Carbon monoxide, which stimulated cocklebur seed germination only slightly, did not cause accumulation of bound HCN. We suggest that a balance between the cytochrome and the alternative respiration pathways, which is adequate for germination (Esashi et al. 1987. Plant Cell Physiol. 28: 141–150), may be brought about by the action of endogenous HCN; a large portion of which is liberated from cyanogenic glycosides via the action of β-glucosidase. In addition to the partial suppression of the cytochrome path and unlike carbon monoxide, the HCN thus produced may act to supply cyanide group(s) to unknown compounds necessary for germination.     

Stimulation of weed seed germination by 1–(3-chlorophthalirnido) cyclohexanecarboxamide (AC 94377)

The N-substituted phthalimide, AC 94377, promoted the germination of dry-stored seeds of 17 out of 24 weed species in Petri-dish tests maintained at 22°C. In a further test it was able to substitute for light and/or alternating temperatures in promoting the germination of some species. AC 94377 was more active than GA, in stimulating Solanum nigrum seed to germinate. When mixed with soil in the laboratory, AC 94377 again promoted germination of S. nigrum but the level and persistence of activity differed between soils. In the glasshouse, with soil containing a natural weed seed population, more seedlings emerged from treated than from untreated soil but this number represented fewer than half of the apparently viable seeds present. Field applications of AC 94377 promoted the germination of hand-sown seeds of certain weed species but did not increase the number of seedlings emerging from the natural weed seed bank.