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991.
Jinping Wu Zhenbiao Jiao Jie Zhou Fengling Guo Zili Ding Zhengming Qiu 《World journal of microbiology & biotechnology》2017,33(7):134
The bacterial community and diversity in healthy and diseased konjac rhizosphere soils with different ages of continuous cropping were investigated using next-generation sequencing. The results demonstrated that the number of years of continuous cropping significantly altered soil bacterial community and diversity. Soil bacterial Shannon diversity index and Chao 1 index decreased with the increasing cropping years of konjac. After 1 year of cropping, the soil exhibited the highest bacterial relative abundance and diversity. Of the 44 bacterial genera (relative abundance ratio of genera greater than 0.3%), 14 were significantly affected by the duration of continuous cropping and plant status. With increasing continuous cropping, Alicyclobacillus decreased, while Achromobacter, Lactobacillus, Kaistobacter, Rhodoplanes increased after 3 years continuous cropping. Continuous cropping altered the structure and composition of the soil bacterial community, which led to the reduction in the beneficial bacteria and multiplication of harmful bacteria. These results will improve our understanding of soil microbial community regulation and soil health maintenance in konjac farm systems. 相似文献
992.
Jatin Machhi Navnit Prajapati Ashutosh Tripathi Zalak S. Parikh Ashish M. Kanhed Kirti Patel Prakash P. Pillai Rajani Giridhar Mange Ram Yadav 《Molecular neurobiology》2017,54(9):6697-6722
Excitotoxicty, a key pathogenic event is characteristic of the onset and development of neurodegeneration. The glutamatergic neurotransmission mediated through different glutamate receptor subtypes plays a pivotal role in the onset of excitotoxicity. The role of NMDA receptor (NMDAR), a glutamate receptor subtype, has been well established in the excitotoxicity pathogenesis. NMDAR overactivation triggers excessive calcium influx resulting in excitotoxic neuronal cell death. In the present study, a series of benzazepine derivatives, with the core structure of 3-methyltetrahydro-3H-benzazepin-2-one, were synthesised in our laboratory and their NMDAR antagonist activity was determined against NMDA-induced excitotoxicity using SH-SY5Y cells. In order to assess the multi-target-directed potential of the synthesised compounds, Aβ1–42 aggregation inhibitory activity of the most potent benzazepines was evaluated using thioflavin T (ThT) and Congo red (CR) binding assays as Aβ also imparts toxicity, at least in part, through NMDAR overactivation. Furthermore, neuroprotective, free radical scavenging, anti-oxidant and anti-apoptotic activities of the two potential test compounds (7 and 14) were evaluated using primary rat hippocampal neuronal culture against Aβ1–42-induced toxicity. Finally, in vivo neuroprotective potential of 7 and 14 was assessed using intracerebroventricular (ICV) rat model of Aβ1–42-induced toxicity. All of the synthesised benzazepines have shown significant neuroprotection against NMDA-induced excitotoxicity. The most potent compound (14) showed relatively higher affinity for the glycine binding site as compared with the glutamate binding site of NMDAR in the molecular docking studies. 7 and 14 have been shown experimentally to abrogate Aβ1–42 aggregation efficiently. Additionally, 7 and 14 showed significant neuroprotective, free radical scavenging, anti-oxidant and anti-apoptotic properties in different in vitro and in vivo experimental models. Finally, 7 and 14 attenuated Aβ1–42-induced tau phosphorylation by abrogating activation of tau kinases, i.e. MAPK and GSK-3β. Thus, the results revealed multi-target-directed potential of some of the synthesised novel benzazepines against excitotoxicity. 相似文献
993.
Advances in synthetic biology are contributing to diverse research areas, from basic biology to biomanufacturing and disease
therapy. We discuss the theoretical foundation, applications, and potential of this emerging field. 相似文献
994.
Tian W Han X Yan M Xu Y Duggineni S Lin N Luo G Li YM Han X Huang Z An J 《Biochemistry》2012,51(2):724-731
Overactivation or overexpression of β-catenin in the Wnt (wingless) signaling pathway plays an important role in tumorigenesis. Interaction of β-catenin with T-cell factor (Tcf) DNA binding proteins is a key step in the activation of the proliferative genes in response to upstream signals of this Wnt/β-catenin pathway. Recently, we identified a new small molecule inhibitor, named BC21 (C(32)H(36)Cl(2)Cu(2)N(2)O(2)), which effectively inhibits the binding of β-catenin with Tcf4-derived peptide and suppresses β-catenin/Tcf4 driven reporter gene activity. This inhibitor decreases the viability of β-catenin overexpressing HCT116 colon cancer cells that harbor the β-catenin mutation, and more significantly, it inhibits the clonogenic activity of these cells. Down-regulation of c-Myc and cyclin D1 expression, the two important effectors of the Wnt/β-catenin signaling, is confirmed by treating HCT116 cells with BC21. This compound represents a new and modifiable potential anticancer candidate that targets β-catenin/Tcf-4 interaction. 相似文献
995.
Diel variation of phytoplankton functional groups in a subtropical reservoir in southern Brazil during an autumnal stratification period 总被引:1,自引:0,他引:1
A knowledge of diel variation and the vertical distribution of phytoplankton communities may contribute to a better understanding
of the driving factors of key species. Applying functional-group classification provides important information on the causes
of species selection in the pelagic community. The diel variation of phytoplankton functional groups was analysed during an
autumnal stratification period with the aim of understanding their changes in the vertical position related to light, mixing
regime and grazing pressure. Phytoplankton and zooplankton communities were sampled every 4 h during a 24-h period in a vertical
profile in a subtropical meso-eutrophic reservoir. Strong stratification during a 24-h cycle and a mixed clear epilimnion
with partial atelomixis marked the autumn season in the Faxinal reservoir, southern Brazil. The highest phytoplankton densities
and biomass were found during the second part of the day, a general pattern reported in the literature, and may be explained
by zooplankton dynamics. During the 24-h cycle, phytoplankton functional groups lacking a self-regulating capacity and those
able to regulate their vertical position were vertically segregated in the lake. The diel behaviour of both groups was driven
by the mixing regime (including atelomixis), light and zooplankton grazing pressure. 相似文献
996.
Fernando S. Henriques 《The Botanical review》2009,75(3):249-270
This review on chlorophyll a fluorescence starts with an overview of the primary photochemistry occurring at PSII and a characterization of the so-called
“open” and “closed” states of its reaction centers. This provides the theoretical background for understanding the origin
of PSII-emitted fluorescence and how its yield varies with the fraction of open reaction centers. The review proceeds to discuss
the changes in fluorescence emission following illumination of a dark-adapted leaf and to define the PSII intrinsic quantum
yield of photochemistry, which in turn provides an indication of PSII capacity. In light-adapted leaves, it is discussed how
the use of modulated fluorometers and the double lighting technique allow an evaluation of photochemical and non-photochemical
quenching, two parameters that give useful information about the plant’s photosynthetic performance under field conditions.
Finally, it is described how the PSII operational efficiency can be used to calculate the photosynthetic electron transport
rate and the conditions under which this is linearly related to the CO2 assimilation rate. Some requirements for a valid application of the technique as well as some limitations in interpreting
its results are discussed.
相似文献
Fernando S. HenriquesEmail: |
997.
Yan Zheng Jing Quan Xin Ning Li-Min Zhu Bo Jiang Zhi-Yan He 《World journal of microbiology & biotechnology》2009,25(1):41-46
Lipase-catalyzed transesterification of soybean oil and methanol for biodiesel production in tert-amyl alcohol was investigated. The effects of different organic medium, molar ratio of substrate, reaction temperature, agitation
speed, lipase dosage and water content on the total conversion were systematically analyzed. Under the optimal conditions
identified (6 mL tert-amyl alcohol, three molar ratio of methanol to oil, 2% Novozym 435 lipase based on the soybean oil weight, temperature 40°C,
2% water content based on soybean oil weight, 150 rpm and 15 h), the highest biodiesel conversion yield of 97% was obtained.
With tert-amyl alcohol as the reaction medium, the negative effects caused by excessive molar ratio of methanol to oil and the by-product
glycerol could be reduced. Furthermore, there was no evident loss in the lipase activity even after being repeatedly used
for more than 150 runs. 相似文献
998.
Nabil M. Abdel-Hamid 《The Journal of membrane biology》2009,230(3):155-162
Chemical composition of extracellular matrix (ECM) plays a pivotal role in cellular and tissue development, regeneration,
and differentiation. It also plays a key role in pathogenesis of hepatocellular carcinoma (HCC). This study explored premalignant
changes in the liver tissue content of collagen (as hydroxyproline, HP), total glycosaminoglycans (TGAGs), free glucosamine
(FGA), total sialic acid (TSA), lysosomal membrane integrity variations (calculated as total and free cathepsin D activities),
and liver histology. Serum alfa-fetoprotein (AFP) level was used as an early marker for HCC in two groups of Wistar rats.
One group of rats served as control and was provided normal saline orally. The other group was provided trichloroacetic acid
(TCA) as 0.5 g/kg/day for five consecutive days by oral gavage. Animals were killed before tumor development. The treatment
revealed dysplastic changes in addition to microsteatosis (fatty changes). Both sinusoids and the portal vein among dysplastic
cells were dilated and congested. These dysplastic foci are believed to be premalignant and may be precancerous lesions. The
following things were observed: a highly significant increase in serum AFP (as a key marker for HCC), a significant decrease
in HP and TSA, a significant increase in FGA, nonsignificant decrease in TGAGs, significant up-regulation of free cathepsin
D, nonsignificant decrease in total cathepsin D activities, and destabilization of lysosomal membrane integrity. Down-regulation
of HP, TSA, and TGAGs seems to be a prerequisite for cancer development. This might be stimulated by up-regulation of free
cathepsin D activity. Perhaps tissue fibrosis is not a condition for developing HCC because collagen was significantly depressed.
Up-regulated FGA could be assumed to be a defense mechanism against TCA-induced proteolysis of membrane proteins because it
is frequently reported to be of value in cancer chemotherapy. Studied ECM perturbations can be assumed as preliminary changes
during chemical hepatocarcinogenesis at the tissue level. Prospective studies on blood levels of cathepsins, TGAGs, and individual
ECM variables such as TSA, FGA, and Hp in patients at risk for HCC, performed in parallel with assessments of AFP, may provide
a cost-effective way to find new links between tissue changes and circulation that would permit early prediction of disease.
It may also provide a way to monitor HCC and compensate for the missed peak AFP values. 相似文献
999.
Background
In the past decades the rapid growth of molecular diagnostics (based on either traditional PCR or isothermal amplification technologies) meet the demand for fast and accurate testing. Although isothermal amplification technologies have the advantages of low cost requirements for instruments, the further improvement on sensitivity, speed and robustness is a prerequisite for the applications in rapid pathogen detection, especially at point-of-care diagnostics. Here, we describe and explore several strategies to improve one of the isothermal technologies, helicase-dependent amplification (HDA). 相似文献1000.
Biological role of MicroRNA-103 based on expression profile and target genes analysis in pigs 总被引:1,自引:0,他引:1
MicroRNAs (miRNAs) are endogenously expressed RNAs consisting of 20–24 nucleotides. These molecules are thought to repress
protein translation by binding to target mRNAs. However, biological functions have not been assigned to most of the 175 porcine
miRNAs registered in miRBase (release 15.0). In an effort to uncover miR-103 important in pigs, we examined the integrative
tissue expression profile and gene ontology (GO) term enrichment of predicted target genes to determine the global biological
functions of miR-103. Our results demonstrated that miR-103 is involved in various biological processes including brain development,
lipid metabolism, adipocyte differentiation, hematopoiesis, and immunity. Moreover, we also experimentally verified effects
of miR-103 in porcine preadipocytes. miR-103 levels increased in differentiating adipocytes, and inhibition of miR-103 effectively
inhibited preadipocyte differentiation. In addition, mRNA levels of the putative miR-103 target RAI14 were higher in miR-103 inhibitor-treated adipocytes. These results demonstrate that miR-103 is involved in porcine preadipocyte
differentiation and may act through the putative target gene RAI14. In a word, our data provide new insights into the global biological role of miR-103. 相似文献