Spatial variation and metabolic diversity of microbial communities in the surface sediments of the Mariana Trench

Mariana Trench represents the deepest and one of least explored biosphere on Earth, and its carbon sources include euphotic sinking, lateral transportation and diffusion from underlying crust, etc. By far the spatial variation of microbial community with associated organic carbon degradation potential in the surface sediments of the Mariana Trench were still largely unknown. Based on the high-throughput 16S rRNA amplicon sequencing, significantly different microbial community structure was overserved between the shallow (<10,000 m) and deep stations (>10,000 m), which could be explained by spatial variation of Chloroflexi, Proteobacteria and Crenarchaeota, with sampling depth and total organic carbon (TOC) content as the environmental driving forces. During the 109-day incubation with Biolog EcoPlate™ microplate, polymers and carbohydrates were preferentially used, followed by amino acids and carboxylic acids, and microbial metabolic diversity was significantly different between the shallow and deep stations. The metabolic diversity of microorganisms at most shallow stations was significantly lower than that at deep stations. This could potentially be attributed the metabolic capabilities of different microbial groups with varied ecological niches, and reflected the initial preference of carbon source by the nature microbes as well. Our study obtained a rough assessment of physiological and taxonomic characteristics of the trench sediment microbial community with polyphasic approaches. Distinct microbial structure and potential carbon metabolic functions in different sampling depths might led to the differentiation of ecological niches, which enable various microorganisms to make full use of the limited resources in the deep sea, and provided a research basis for further exploration of the carbon cycle in different deep-sea regions

Fault diagnosis of electro-mechanical actuator based on WPD-STFT time-frequency entropy and PNN

Electro-mechanical actuators (EMAs) are increasingly being used as critical actuation devices of the aircraft. It will cause serious accidents once the fault of EMAs occurs, thus the fault diagnosis of EMAs is essential to maintain the normal operation of aircraft. In this paper, a method based on WPD-STFT time-frequency entropy and PNN is proposed to achieve fault diagnosis of EMAs by processing the vibration signals collected by the accelerometer installed in the EMAs. Firstly, the vibration signals are decomposed by wavelet packet to obtain the signal components of different frequency bands, the signal components are subjected to STFT and spectrograms are obtained. Then, time-frequency entropy is calculated and combined with principal component analysis (PCA) for dimension reduction as the feature vector. Finally, the probabilistic neural network (PNN) classifier is introduced to classify the fault modes. The experimental result shows that this method can accomplish the accurate fault diagnosis of EMAs. Moreover, the performance of the proposed WPD-STFT time-frequency entropy method has an advantage over that of WPD-PCA method or STFT combined with mass-moment entropy method for feature extraction

Rolling Bearing Fault Detection Based on the Teager Energy Operator and Elman Neural Network

This paper presents an approach to bearing fault diagnosis based on the Teager energy operator (TEO) and Elman neural network. The TEO can estimate the total mechanical energy required to generate signals, thereby resulting in good time resolution and self-adaptability to transient signals. These attributes reflect the advantage of detecting signal impact characteristics. To detect the impact characteristics of the vibration signals of bearing faults, we used the TEO to extract the cyclical impact caused by bearing failure and applied the wavelet packet to reduce the noise of the Teager energy signal. This approach also enabled the extraction of bearing fault feature frequencies, which were identified using the fast Fourier transform of Teager energy. The feature frequencies of the inner and outer faults, as well as the ratio of resonance frequency band energy to total energy in the Teager spectrum, were extracted as feature vectors. In order to avoid a frequency leak error, the weighted Teager spectrum around the fault frequency was extracted as feature vector. These vectors were then used to train the Elman neural network and improve the robustness of the diagnostic algorithm. Experimental results indicate that the proposed approach effectively detects bearing faults under variable conditions

Rolling Bearing Fault Diagnosis Based on EMD-TEO and Mahalanobis Distance

A intelligent rolling bearing fault diagnosis method is proposed on Empirical Mode Decomposition (EMD) – Teager Energy Operator (TEO) and Mahalanobis distance. EMD can adaptively decompose vibration signal into a series of Intrinsic Mode Functions (IMFs), that is, zero mean mono-component AM-FM signal. TEO can estimate the total mechanical energy required to generate signals, so it has good time resolution and self-adaptive ability to the transient of the signal, which shows the advantage to detect the signal impact characteristics. With regards to the impulse feature of the bearing fault vibration signals, TEO can be used to detect cyclical impulse characteristic caused by bearing failure, gain the instantaneous amplitude spectrum of each IMF component, then identify the characteristic frequency of the interesting and single IMF component in bearing faults by means of Teager energy spectrum. The amplitude of the Teager energy spectrum in inner race fault frequency, outer fault frequency and the ratio of the energy of the resonance frequency to the total energy were extracted as the feature vectors, which were used as training samples and test samples separately for fault diagnosis. Then the Mahalanobis distances between the real measure and different type overalls of fault sample are calculated to classify the real condition of rolling bearing. Experimental results was concluded that this method can accurately identify and diagnose different fault types of rolling bearing

Magnetic Fe3O4 nanoparticles and chemotherapy agents interact synergistically to induce apoptosis in lymphoma cells

The purpose of this study was to investigate the potential effects of combination therapy using magnetic nanoparticles of Fe3O4 (MNP-Fe3O4) and chemotherapeutic drugs on lymphoma cells. Proliferation, inhibition, and viability of Raji cells were detected by MTT and trypan blue exclusion. The percentage of cells undergoing apoptosis was detected by flow cytometry using fluorescein isothiocyanate-annexin V and propidium iodide staining. p53 and nuclear factor-κB (NF-κB) protein levels were measured by Western blot. The results showed that proliferation of Raji cells was inhibited by adriamycin or daunorubicin in a dose-and time-dependent manner. Cell sensitivity was improved and the 50% inhibitory concentrations of adriamycin and daunorubicin decreased when combined with a MNP-Fe3O4 carrier. Interestingly, increased apoptosis in Raji lymphoma cells was accompanied by upregulation of p53 protein and downregulation of NF-κB protein. Furthermore, the combination of MNP-Fe3O4 with adriamycin or daunorubicin increased p53 protein levels and decreased NF-κB protein levels more than adriamycin or daunorubicin alone, indicating that MNP-Fe3O4 could enhance the effect of chemotherapeutic drugs on p53 and NF-κB. Similar results for cell apoptosis and protein expression were not observed for the groups treated with dexamethasone ± MNP-Fe 3O4 (P > 0.05). These findings suggest a potential clinical application for MNP-Fe3O4 in combination with daunorubicin or adriamycin in the treatment of lymphoma

Natural anti-phytopathogenic fungi compound phenol, 2, 4-bis (1, 1-dimethylethyl) from Pseudomonas fluorescens TL-1

A strain was isolated from tobacco phylloplane and preliminarily identified as Pseudomonas fluorescens TL-1, which had the visible inhibition against ten plant pathogenic fungi, viz., Curvularia lunata, Bipolaris maydis, Valsa mali, Rhizoctonia solani, Colletotrichum gloeosporioides, Sclerotinia sclerotiorum, Botrytis cinerea, Alternaria alternate, Fusarium oxysporum and Verticillium dahlia in dual culture experiments. The ethyl acetate extract of nutrient broth seeded with Pseudomonas fluorescens TL-1 suspension was separated into fifty-nine fractions by the Sephadex LH-20 column and the antifungal activity of each fraction was tested with paper disc diffusion method against Curvularia lunata. The results showed that fraction 1 to 3 had the strongest inhibitory effects on Curvularia lunata. Furthermore, GC/MS analysis of the constituents of fraction 1 to 59 confirmed that phenol, 2, 4-bis (1, 1-dimethylethyl) was the active compound for the antifungal activity from Pseudomonas fluorescens TL-1

The tonoplast-localized transporter OsHMA3 plays an important role in maintaining Zn homeostasis in rice

In order to respond to fluctuating zinc (Zn) in the environment, plants must have a system to control Zn homeostasis. However, how plants maintain an appropriate level of Zn during their growth and development is still poorly understood. In this study, we found that OsHMA3, a tonoplast-localized transporter for Zn/Cd, plays an important role in Zn homeostasis in rice. Accessions with the functional allele of OsHMA3 showed greater tolerance to high Zn than those with the non-functional allele based on root elongation test. A 67Zn-labeling experiment showed that accessions with loss of function of OsHMA3 had lower Zn accumulation in the roots but similar concentrations in the shoots compared with functional OsHMA3 accessions. When exposed to Zn-free growing medium, the concentration in the root cell sap was rapidly decreased in accessions with functional OsHMA3, but less dramatic changes were observed in non-functional accessions. A mobility experiment showed that more Zn in the roots was translocated to the shoots in accessions with functional OsHMA3. Higher expression levels of OsZIP4, OsZIP5, OsZIP8, and OsZIP10 were found in the roots of accessions with functional OsHMA3 in response to Zn deficiency. Taken together, our results indicate that OsHMA3 plays an important role in rice roots in both Zn detoxification and storage by sequestration into the vacuoles, depending on Zn concentration in the environment

Anthropogenic impact on diazotrophic diversity in the mangrove rhizosphere revealed by nifH pyrosequencing

Diazotrophs in the mangrove rhizosphere play a major role in providing new nitrogen to the mangrove ecosystem and their composition and activity are strongly influenced by anthropogenic activity and ecological conditions. In this study, the diversity of the diazotroph communities in the rhizosphere sediment of five tropical mangrove sites with different levels of pollution along the north and south coastline of Singapore were studied by pyrosequencing of the nifH gene. Bioinformatics analysis revealed that in all the studied locations, the diazotroph communities comprised mainly of members of the diazotrophic cluster I and cluster III. The detected cluster III diazotrophs, which were composed entirely of sulfate-reducing bacteria, were more abundant in the less polluted locations. The metabolic capacities of these diazotrophs indicate the potential for bioremediation and resiliency of the ecosystem to anthropogenic impact. In heavily polluted locations, the diazotrophic community structures were markedly different and the diversity of species was significantly reduced when compared with those in a pristine location. This, together with the increased abundance of Marinobacterium, which is a bioindicator of pollution, suggests that anthropogenic activity has a negative impact on the genetic diversity of diazotrophs in the mangrove rhizosphere

Lipin1 Regulates Skeletal Muscle Differentiation through Extracellular Signal-regulated Kinase (ERK) Activation and Cyclin D Complex-Regulated Cell Cycle Withdrawal

Lipin1, an intracellular protein, plays critical roles in controlling lipid synthesis and energy metabolism through its enzymatic activity and nuclear transcriptional functions. Several mouse models of skeletal muscle wasting are associated with lipin1 mutation or altered expression. Recent human studies have suggested that children with homozygous null mutations in the LPIN1 gene suffer from rhabdomyolysis. However, the underlying pathophysiologic mechanism is still poorly understood. In the present study we examined whether lipin1 contributes to regulating muscle regeneration. We characterized the time course of skeletal muscle regeneration in lipin1-deficient fld mice after injury. We found that fld mice exhibited smaller regenerated muscle fiber cross-sectional areas compared with wild-type mice in response to injury. Our results from a series of in vitro experiments suggest that lipin1 is up-regulated and translocated to the nucleus during myoblast differentiation and plays a key role in myogenesis by regulating the cytosolic activation of ERK1/2 to form a complex and a downstream effector cyclin D3-mediated cell cycle withdrawal. Overall, our study reveals a previously unknown role of lipin1 in skeletal muscle regeneration and expands our understanding of the cellular and molecular mechanisms underlying skeletal muscle regeneration