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241.
本文用光学显微镜和扫描电镜对16属46种2变种的旋花科植物花粉形态进行了观察。本科的花粉为多类型。3沟为基本的萌发孔类型。根据萌发孔的形状、位置和数目,本科花粉可分为3沟、4-11沟、散沟和散孔4个类型。根据孢粉学资料、本文对菟丝子属(Cuscuta)在旋花科中的分类位置及其本科萌发孔的演化趋向等问题进行了讨论。 相似文献
242.
The chlorophyll recovery efficiency was compared between control, ground, and sonified samples. The results showed significant improvement between control and ground samples but not between control and sonified samples. Neither prolonging time of sonification nor using an ice bath during filter grinding improved efficiency. Higher chlorophyll a recovery was obtained from ground samples than from sonified ones, when the water samples contained centric diatoms and filamentous blue-green algae. When total phytoplankton numbers were high, there was a distinct advantage in using grinding rather than sonification for chlorophyll c recovery.Contribution no. 313 of the Great Lakes Research Division, University of Michigan.Contribution no. 313 of the Great Lakes Research Division, University of Michigan. 相似文献
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Li Songtao Zhao Hongling Wang Ruxing Wang Jianping Mao Xiaoxia Hao Ting Chang Xiaomin Zhao Enhong Yin Zhifeng Deng Shuhua Yang Yaqi Wang Huina 《International journal of peptide research and therapeutics》2019,25(4):1361-1367
International Journal of Peptide Research and Therapeutics - It is demonstrated that gonadotropin-releasing hormone (GnRH) analogs can directly inhibit the proliferation of reproductive tissue... 相似文献
245.
Wu H Kao SC Barrientos T Baldwin SH Olson EN Crabtree GR Zhou B Chang CP 《The Journal of biological chemistry》2007,282(42):30673-30679
246.
Plum is a highly perishable fruit and postharvest fruit softening limits its shelf life. The aim of this work was to study
the specific effects of 1-methylcyclopropene (1-MCP) treatment on physiological changes in ‘Zaohong’ plums. Plums were treated
with 500 nL L−1 1-MCP at 20°C for 18 h followed by 20°C storage. The results showed that 1-MCP treatment significantly reduced endogenous
ethylene production and the activities of ethylene biosynthetic enzymes’ (1-aminocyclopropane-1-carboxylic acid synthase,
ACS and 1-aminocyclopropane-1-carboxylic acid oxidase, ACO) in plum fruit during storage when compared with untreated fruit.
Although 1-MCP treatment inhibited ethylene production and 1-aminocyclopropane-1-carboxylic acid (ACC) accumulation, it did
not inhibit the accumulation of N-malonyl-ACC (MACC). Higher firmness was also found in 1-MCP-treated plums than in controls. During storage, superoxide anion
(O2−·) and hydrogen peroxide (H2O2) levels decreased in 1-MCP-treated fruit. 1-MCP treatment also regulated superoxide dismutase (SOD) and catalase (CAT) activities
during storage. Xylanase activity was upregulated while activities of polygalacturonase (PG), pectin methyl esterase (PME)
and cellulase enzymes in the fruit were downregulated by 1-MCP treatment. In conclusion, 1-MCP might be a potent compound
for extending both storage period and shelf life of ‘Zaohong’ plums by suppressing ethylene biosynthesis, regulating cell
wall degradation enzymes and reducing fruit softening. 相似文献
247.
Po-Chun Chang Chun-Jen Wang Chung-Kai You Mou-Chieh Kao 《Biochemical and biophysical research communications》2011,(3):1641
Lipopolysaccharide (LPS) is considered as an important virulence factor of Helicobacter pylori, and contributes to infection persistence and disease severity. ADP-l-glycero-d-manno-heptose-6-epimerase is an enzyme essential for LPS synthesis and understanding of its biochemistry is critical for drug development. We cloned one putative ortholog of Escherichia colirfaD, HP0859, from H. pylori 26695. Determination of the native molecular weight of the recombinant HP0859 protein suggests that the protein is likely a hexamer. NADP+, instead of NAD+, was proved to be the physiological cofactor for HP0859 protein. Circular dichroism spectrum analysis demonstrated that the secondary structure of this protein is significantly altered when the cofactor is removed. We also constructed an HP0859 knockout mutant and examined its phenotypic properties. The HP0859 knockout mutant exhibited a severe truncation of LPS, a decreased growth rate, and a higher susceptibility to novobiocin. Disruption of HP0859 also reduced the adhesive capacity of H. pylori to AGS cells, and the infected cells failed to display the classic hummingbird phenotype. Complementation of the HP0859 knockout mutation restored these phenotypes completely. In conclusion, we demonstrate that HP0859 codes for a protein essential for the LPS inner core biosynthesis in H. pylori and an intact LPS structure contributes to the adherence ability of this bacterium. 相似文献
248.
Xiang Z. Li Byung K. Park Jong S. Shin Seong H. Choi Stephen B. Smith Chang G. Yan 《PloS one》2015,10(5)
The rumen microbial ecosystem is a complex system where rumen fermentation processes involve interactions among microorganisms. There are important relationships between diet and the ruminal bacterial composition. Thus, we investigated the ruminal fermentation characteristics and compared ruminal bacterial communities using tag amplicon pyrosequencing analysis in Yanbian yellow steers, which were fed linseed oil (LO) and propionate precursors. We used eight ruminally cannulated Yanbian yellow steers (510 ± 5.8 kg) in a replicated 4 × 4 Latin square design with four dietary treatments. Steers were fed a basal diet that comprised 80% concentrate and 20% rice straw (DM basis, CON). The CON diet was supplemented with LO at 4%. The LO diet was also supplemented with 2% dl-malate or 2% fumarate as ruminal precursors of propionate. Dietary supplementation with LO and propionate precursors increased ruminal pH, total volatile fatty acid concentrations, and the molar proportion of propionate. The most abundant bacterial operational taxonomic units in the rumen were related to dietary treatments. Bacteroidetes dominated the ruminal bacterial community and the genus Prevotella was highly represented when steers were fed LO plus propionate precursors. However, with the CON and LO diet plus malate or fumarate, Firmicutes was the most abundant phylum and the genus Ruminococcus was predominant. In summary, supplementing the diets of ruminants with a moderate level of LO plus propionate precursors modified the ruminal fermentation pattern. The most positive responses to LO and propionate precursors supplementation were in the phyla Bacteriodetes and Firmicutes, and in the genus Ruminococcus and Prevotella. Thus, diets containing LO plus malate or fumarate have significant effects on the composition of the rumen microbial community. 相似文献
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