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51.
Dental caries is a common oral bacterial infectious disease of global concern. Prevention and treatment of caries requires control of the dental plaque formed by pathogens such as Streptococcus mutans and Streptococcus sobrinus. Pleurocidin, produced by Pleuronectes americanus, is an antimicrobial peptide that exerts broad-spectrum activity against pathogenic bacteria and fungi. Moreover, pleurocidin shows less hemolysis and is less toxic than other natural peptides. In the present study, we investigated whether pleurocidin is an effective antibiotic peptide against common cariogenic microorganisms and performed a preliminary study of the antimicrobial mechanism. We assayed minimal inhibitory concentration (MIC), minimal bactericide concentration (MBC) and bactericidal kinetics and performed a spot-on-lawn assay. The BioFlux system was used to generate bacterial biofilms under controllable flow. Fluorescence microscopy and confocal laser scanning microscopy (CLSM) were used to analyze and observe biofilms. Scanning electron microscopy was used to observe the bacterial membrane. MIC and MBC results showed that pleurocidin had different antimicrobial activities against the tested oral strains. Although components of saliva could affect antimicrobial activity, pleurocidin dissolved in saliva still showed antimicrobial effects against oral microorganisms. Furthermore, pleurocidin showed a favorable killing effect against BioFlux flow biofilms in vitro. Our findings suggest that pleurocidin has the potential to kill dental biofilms and prevent dental caries. 相似文献
52.
Basal thermotolerance is very important for plant growth and development when plants are subjected to heat stress. However, little is known about the functional mechanism of gibberellins (GAs) in the basal thermotolerance of plants. In the present work, we provide molecular evidence that a member of the gene family encoding the GA-stimulated Arabidopsis (GASA) peptides, namely GASA5, is involved in the regulation of seedling thermotolerance. The GASA5-overexpressing plants displayed a weak thermotolerance, with a faster cotyledon-yellowing rate, lower seedling-survival rate, and slower hypocotyl elongation, in comparison to the wild-type and GASA5 null-mutant (gasa5-1) plants, after heat-stress treatment. The short-hypocotyl phenotype of GASA5-overexpressing plants could be rescued by the exogenous application of salicylic acid (SA), the hormone found to protect plants from heat stress-induced damage. GASA5 expression was inhibited by heat stress but unaffected by the application of exogenous SA. However, expression of the gene encoding the noexpresser of PR genes 1 (NPR1), a key component of the SA-signaling pathway, was downregulated by GASA5 overexpression. Importantly, when different GASA5-genotype plants were treated with heat stress, several genes encoding heat-shock proteins, including HSP101, HSP70B, HSP90.1, HSP17.6-C1, and HSP60, were inhibited by GASA5 overexpression. Meanwhile, hydrogen peroxide was accumulated at high levels in heat stress-treated GASA5-overexpressing plants. These results suggest that the Arabidopsis GASA5 gene acts as a negative regulator in thermotolerance by regulating both SA signaling and heat shock-protein accumulation. 相似文献
53.
M. Sang X. -C. Qin W. -D. Wang J. Xie X. -B. Chen K. B. Wang J. -P. Zhang L. -B. Li T. Y. Kuang 《Photosynthetica》2011,49(1):48-54
The generation of superoxide anion radical (O2
·−) in the cytochrome b
6
f complex (Cyt b
6
f) of spinach under high-light illumination was studied using electron paramagnetic resonance spectroscopy. The generation
of O2
·− was lost in the absence of molecular oxygen. It was also suppressed in the presence of NaN3 and could be scavenged by extraneous antioxidants such as ascorbate, β-carotene, and glutathione. The results also indicate that O2
·−, which is produced under high-light illumination of the Cyt b
6
f from spinach, might be generated from a reaction involing 1O2, and the Rieske Fe-S protein could serve as the electron donor in the O2
·− production. The mechanism of photoprotection of the Cyt b
6
f complex by antioxidants is discussed. 相似文献
54.
Yang R Li J Wang X Zhou X 《TAG. Theoretical and applied genetics. Theoretische und angewandte Genetik》2011,123(3):483-492
Without consideration of other linked QTLs responsible for dynamic trait, original functional mapping based on a single QTL
model is not optimal for analyzing multiple dynamic trait loci. Despite that composite functional mapping incorporates the
effects of genetic background outside the tested QTL in mapping model, the arbitrary choice of background markers also impact
on the power of QTL detection. In this study, we proposed Bayesian functional mapping strategy that can simultaneously identify
multiple QTL controlling developmental patterns of dynamic traits over the genome. Our proposed method fits the change of
each QTL effect with the time by Legendre polynomial and takes the residual covariance structure into account using the first
autoregressive equation. Also, Bayesian shrinkage estimation was employed to estimate the model parameters. Especially, we
specify the gamma distribution as the prior for the first-order auto-regressive coefficient, which will guarantee the convergence
of Bayesian sampling. Simulations showed that the proposed method could accurately estimate the QTL parameters and had a greater
statistical power of QTL detection than the composite functional mapping. A real data analysis of leaf age growth in rice
is used for the demonstration of our method. It shows that our Bayesian functional mapping can detect more QTLs as compared
to composite functional mapping. 相似文献
55.
Shuen‐Fang Lo Ien‐Chie Wen Yi‐Lun Liu Ku‐Ting Chen Mirng‐Jier Jiang Ming‐Kuang Lin Meng‐Yen Rao Lin‐Chih Yu Tuan‐Hua David Ho Su‐May Yu 《Plant, cell & environment》2016,39(5):998-1013
Rice is an important crop and major model plant for monocot functional genomics studies. With the establishment of various genetic resources for rice genomics, the next challenge is to systematically assign functions to predicted genes in the rice genome. Compared with the robustness of genome sequencing and bioinformatics techniques, progress in understanding the function of rice genes has lagged, hampering the utilization of rice genes for cereal crop improvement. The use of transfer DNA (T‐DNA) insertional mutagenesis offers the advantage of uniform distribution throughout the rice genome, but preferentially in gene‐rich regions, resulting in direct gene knockout or activation of genes within 20–30 kb up‐ and downstream of the T‐DNA insertion site and high gene tagging efficiency. Here, we summarize the recent progress in functional genomics using the T‐DNA‐tagged rice mutant population. We also discuss important features of T‐DNA activation‐ and knockout‐tagging and promoter‐trapping of the rice genome in relation to mutant and candidate gene characterizations and how to more efficiently utilize rice mutant populations and datasets for high‐throughput functional genomics and phenomics studies by forward and reverse genetics approaches. These studies may facilitate the translation of rice functional genomics research to improvements of rice and other cereal crops. 相似文献
56.
Qilei Wang Xiaojing Xue Yuling Li Yongbin Dong Long Zhang Qiang Zhou Fei Deng Zhiyan Ma Dahe Qiao Chunhui Hu Yangliu Ren 《Physiologia plantarum》2016,156(1):97-107
ADP‐ribosylation factors (ARFs) are small GTP‐binding proteins that regulate a wide variety of cell functions. Previously, we isolated a new ARF, ZmArf2, from maize (Zea mays). Sequence and expression characteristics indicated that ZmArf2 might play a critical role in the early stages of endosperm development. In this study, we investigated ZmArf2 function by analysis of its GTP‐binding activity and subcellular localization. We also over‐expressed ZmArf2 in Arabidopsis and measured organ and cell size and counted cell numbers. The expression levels of five organ size‐associated genes were also determined in 35S::ZmArf2 transgenic and wild‐type plants. Results showed that the recombinant ZmArf2 protein purified from Escherichia coli exhibited GTP‐binding activity. Subcellular localization revealed that ZmArf2 was localized in the cytoplasm and plasma membrane. ZmArf2 over‐expression in Arabidopsis showed that 35S::ZmArf2 transgenic plants were taller and had larger leaves and seeds compared to wild‐type plants, which resulted from cell expansions, not an increase in cell numbers. In addition, three cell expansion‐related genes, AtEXP3, AtEXP5 and AtEXP10, were upregulated in 35S::ZmArf2 transgenic lines, while the expression levels of AtGIF1 and AtGRF5, were unchanged. Collectively, our studies suggest that ZmArf2 has an active GTP‐binding function, and plays a crucial role in growth and development in Arabidopsis through cell expansion mediated by cell expansion genes. 相似文献
57.
Wang T Cong R Yang H Wu MM Luo N Kuang F You SW 《Cellular and molecular neurobiology》2011,31(3):357-364
Transplantation of olfactory ensheathing cells (OECs) becomes one of the promising strategies in restoring lost functions
of injured central nervous system. Elevated level of expressed brain-derived neurotrophic factor (BDNF) was revealed in the
previous studies to be related to the protective effects of OECs on injured cortical and brain stem neurons as well as retinal
ganglion cells (RGCs), but no evidence has been obtained to demonstrate whether transplanted OECs protect injured central
neurons directly by their secreted BDNF. In the present study, the effects of BDNF neutralization on the neuroprotection of
adult OEC-conditioned medium (OEC-CM) on scratch-insulted RGCs were examined. The results showed that OEC-CM protected cultured
RGCs from scratch insult, and neutralization of BDNF by BDNF neutralizing antibody attenuated such neuroprotection of the
medium. It is thus concluded that neurotrophic factors including BDNF secreted by OECs can protect injured OECs in vitro and
BDNF plays a major role in such a protection of OECs. 相似文献
58.
为延长枸杞鲜果的贮存时间,开发专用植物源保鲜剂,采用浸泡法初步研究18种植物提取物对枸杞鲜果的保鲜作用。结果表明,荷叶乙醇提取物和柠檬油对枸杞鲜果具有较好的保鲜活性,在1 g/L和1 mL/L剂量时,处理5 d后好果率分别为78.64%和72.22%,质量损失率分别为7.68%和8.13%,显著优于标准药剂1-甲基环丙烯(1-MCP 0.25 μL/L,P<0.05);其次为肉桂油、丁香叶油、香紫苏油、卡楠加油、丹参提取物和知母提取物,好果率均在50%以上;最佳使用剂量筛选表明,荷叶乙醇提取物和柠檬油二者分别在2 g/L和400 μL/L时对枸杞鲜果的保鲜效果最好,处理5 d后枸杞鲜果好果率均在80%以上,显著优于1-MCP(0.25 μL/L)处理。可见荷叶提取物和柠檬油对枸杞鲜果具有较好的保鲜活性,值得进一步研究。 相似文献
59.
A study on the constitutive equation of blood. 总被引:1,自引:0,他引:1
60.
Wasim Ahmed Xiaojing Yan Dekun Hu Muhammad Adnan Ri-Yuan Tang Zi-Ning Cui 《Bioorganic & medicinal chemistry》2019,27(19):115048
Pyrazole constitutes an important heterocyclic family covering a broad range of synthetic as well as natural products that exhibit numerous chemical, biological, agrochemical and pharmacological properties. In order to explore compounds with good fungicidal activity, a series of new pyrazole derivatives containing 5-phenyl-2-furan were designed and synthesized. In vitro and in vivo fungicidal activities were evaluated and the compound ethyl-1-(5-phenylfuran-2-carbonyl)-5-propyl-1H-pyrazole-3-carboxylate (I8) displayed significant fungicidal activity against various fungi, especially against P. infestans. The structures of the novel pyrazole derivatives were confirmed by 1H NMR, 13C NMR, MS, elemental analysis and X-ray single crystal diffraction. Further study showed that compound I8 might act on the synthesis of cell walls from morphological and ultrastructural studies by SEM and TEM. The results also revealed that compound I8 could block the nutritional transportation leading to cells senescence and death. These results suggested that the novel pyrazole derivatives proved to be promising lead compounds. 相似文献