31 research outputs found

    The novel cis-encoded antisense RNA AsrC positively regulates the expression of rpoE-rseABC operon and thus enhances the motility of Salmonella enterica serovar typhi

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    Bacterial noncoding RNAs are essential in many cellular processes, including response to environmental stress, and virulence. Deep sequencing analysis of the Salmonella enterica serovar Typhi (S. Typhi) transcriptome revealed a novel antisense RNA transcribed in cis on the strand complementary to rseC, an activator gene of sigma factor RpoE. In this study, expression of this antisense RNA was confirmed in S. Typhi by Northern hybridization. Rapid amplification of cDNA ends and sequence analysis identified an 893 bp sequence from the antisense RNA coding region that covered all of the rseC coding region in the reverse direction of transcription. This sequence of RNA was named as AsrC. After overexpression of AsrC with recombinantant plasmid in S. Typhi, the bacterial motility was increased obviously. To explore the mechanism of AsrC function, regulation of rseC and rpoE expression by AsrC was investigated. We found that AsrC increased the levels of rseC mRNA and protein. The expression of rpoE was also increased in S. Typhi after overexpression of AsrC, which was dependent on rseC. Thus, we propose that AsrC increased RseC level and indirectly activating RpoE which can initiate fliA expression and promote the motility of S. Typhi

    Metabolic engineering of the moss <i>Physcomitrella patens</i> to produce the sesquiterpenoids patchoulol and Ī±/Ī²-santalene

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    The moss Physcomitrella patens, has been genetically engineered to produce patchoulol and Ī²-santalene, two valuable sesquiterpenoid ingredients in the fragrance industry. The highest yield of patchoulol achieved was 1.34 mg/g dry weight. This was achieved by non-targeted transformation of the patchoulol synthase and either a yeast or P. patens HMGR gene under the control of a 35S promoter. Santalene synthase targeted to the plastids yielded 0.039 mg/g dry weight of Ī±/Ī² santalene; cytosolic santalene synthase and 35S controlled HMGR afforded 0.022 mg/g dry weight. It has been observed that the final yield of the fragrance molecules is dependent on the expression of the synthase. This is the first report of heterologous production of sesquiterpenes in moss and it opens up a promising source for light-driven production of valuable fragrance ingredients

    Multi-Modal MRI Analysis with Disease-Specific Spatial Filtering: Initial Testing to Predict Mild Cognitive Impairment Patients Who Convert to Alzheimerā€™s Disease

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    Background: Alterations of the gray and white matter have been identified in Alzheimerā€™s disease (AD) by structural magnetic resonance imaging (MRI) and diffusion tensor imaging (DTI). However, whether the combination of these modalities could increase the diagnostic performance is unknown. Methods: Participants included 19 AD patients, 22 amnestic mild cognitive impairment (aMCI) patients, and 22 cognitively normal elderly (NC). The aMCI group was further divided into an ā€œaMCI-converterā€ group (converted to AD dementia within 3ā€‰years), and an ā€œaMCI-stableā€ group who did not convert in this time period. A T1-weighted image, a T2 map, and a DTI of each participant were normalized, and voxel-based comparisons between AD and NC groups were performed. Regions-of-interest, which defined the areas with significant differences between AD and NC, were created for each modality and named ā€œdisease-specific spatial filtersā€ (DSF). Linear discriminant analysis was used to optimize the combination of multiple MRI measurements extracted by DSF to effectively differentiate AD from NC. The resultant DSF and the discriminant function were applied to the aMCI group to investigate the power to differentiate the aMCI-converters from the aMCI-stable patients. Results: The multi-modal approach with AD-specific filters led to a predictive model with an area under the receiver operating characteristic curve (AUC) of 0.93, in differentiating aMCI-converters from aMCI-stable patients. This AUC was better than that of a single-contrast-based approach, such as T1-based morphometry or diffusion anisotropy analysis. Conclusion: The multi-modal approach has the potential to increase the value of MRI in predicting conversion from aMCI to AD

    Current Status and Outlook in the Application of Microalgae in Biodiesel Production and Environmental Protection

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    Microalgae have been currently recognized as one group of the most potential feedstocks for biodiesel production due to high productivity potential, efficient biosynthesis of lipids and less competition with food production. Moreover, utilization of microalgae with environmental purposes (CO2 fixation, NOX and wastewater treatment) and biorefinery have been reported. However, there are still challenges that need to be addressed to ensure stable large-scale production with positive net energy balance. This review gives an overview of the current status of the application of microalgae in biodiesel production and environmental protection. The practical problems not only facing the microalgae biodiesel production but also associated with microalgae application for environmental pollution control, in particular biological fixation of greenhouse gas (CO2 and NOX) and wastewater treatment are described in detail. Notably, the synergistic combination of various applications (e.g. food, medicine, wastewater treatment and flue gas treatment) with biodiesel production could enhance the sustainability and economics of the algal biodiesel production system

    Selectively disrupted functional connectivity networks in type 2 diabetes mellitus

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    Background: The high prevalence of type 2 diabetes mellitus (T2DM) in individuals over 65 years old and cognitive deficits caused by T2DM have attracted broad attention. The pathophysiological mechanism of T2DM induced cognitive impairments, however, remains poorly understood. Previous studies have suggested that the cognitive impairments can be attributed not merely to local functional and structural abnormalities but also to specific brain networks. Thus, we aimed to investigate the changes of global networks selectively affected by T2DM. Methods: A resting state functional network analysis was conducted to investigate the intrinsic functional connectivity in 37 patients with diabetes and 40 healthy controls which were recruited from local communities in Beijing, China. Results: We found that patients with T2DM exhibited cognitive function declines and functional connectivity disruptions within the default mode network, left frontal parietal network, and sensorimotor network. More importantly, the fasting glucose level was correlated with abnormal functional connectivity.Conclusions: These findings could help to understand the neural mechanisms of cognitive impairments in T2DM and provide potential neuroimaging biomarkers that may be used for early diagnosis and intervention in cognitive decline

    Social anxiety, stress type, and conformity among adolescents

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    Social anxiety and stress type can influence strong conformity among adolescents; however, the interaction between them is not clear. In this study, 152 adolescents were recruited and assigned one of two conditions: an interaction and a judgment condition. In the interaction condition, adolescents with high social anxiety were less likely to conform when completing a modified Asch task, compared to adolescents who had low social anxiety. In the judgment condition, adolescents with high social anxiety were more likely to conform to the opinions from the unanimous majority. The results suggest that adolescents with high social anxiety may show different styles of strong conformity with the change of stress type. We believe that socially anxious adolescents avoid potential social situations with weaker conformity, while avoiding negative evaluations from others with stronger conformity. These findings contribute to a better understanding of the social dysfunctions among adolescents with high social anxiety and provide a new direction for clinical interventions

    Improved Productivity of Neutral Lipids in Chlorella sp. A2 by Minimal Nitrogen Supply

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    Nitrogen starvation is an efficient environmental pressure for increasing lipid accumulation in microalgae, but it could also significantly lower the biomass productivity, resulting in lower lipid productivity. In this study, green alga Chlorella sp. A2 was cultivated by using a minimal nitrogen supply strategy under both laboratory and outdoor cultivation conditions to evaluate biomass accumulation and lipid production. Results showed that minimal nitrogen supply could promote neutral lipid accumulation of Chlorella sp. A2 without a significant negative effect on cell growth. In laboratory cultivation mode, alga cells cultured with 18 mg L-1 d-1 urea addition could generate 74% and 416% (w/w) more neutral lipid productivity than cells cultured with regular BG11 and nitrogen starvation media, respectively. In outdoor cultivation mode, lipid productivity of cells cultured with 18 mg L-1 d-1 urea addition is approximately 10% and 88% higher than the one with regular BG11 and nitrogen starvation media, respectively. Notably, the results of photosynthetic analysis clarified that minimal nitrogen supply reduced the loss of photosynthetic capacity to keep CO2 fixation during photosynthesis for biomass production. The minimal nitrogen supply strategy for microalgae cultivation could promote neutral lipid accumulation without a significant negative effect on cell growth, resulting in a significant improvement in the lipid productivity

    SLE: Another Autoimmune Disorder Influenced by Microbes and Diet?

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    Systemic lupus erythematosus (SLE) is a multi-system autoimmune disease. Despite years of study, the etiology of SLE is still unclear. Both genetic and environmental factors have been implicated in the disease mechanisms. In the past decade, a growing body of evidence has indicated an important role of gut microbes in the development of autoimmune diseases, including type 1 diabetes, rheumatoid arthritis and multiple sclerosis. However, such knowledge on SLE is little, though we have already known that environmental factors can trigger the development of lupus. Several recent studies have suggested that alterations of the gut microbial composition may be correlated with SLE disease manifestations, while the exact roles of either symbiotic or pathogenic microbes in this disease remain to be explored. Elucidation of the roles of gut microbesā€”as well as the roles of diet that can modulate the composition of gut microbesā€”in SLE will shed light on how this autoimmune disorder develops, and provide opportunities for improved biomarkers of the disease and the potential to probe new therapies. In this review, we aim to compile the available evidence on the contributions of diet and gut microbes to SLE occurrence and pathogenesis

    Task-related Functional Connectivity Dynamics in a Block-designed Visual Experiment

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    Studying task modulations of brain connectivity using functional magnetic resonance imaging (fMRI) is critical to understand brain functions that support cognitive and affective processes. Existing methods such as psychophysiological interaction (PPI) and dynamic causal modelling (DCM) usually implicitly assume that the connectivity patterns are stable over a block-designed task with identical stimuli. However, this assumption lacks empirical verification on high-temporal resolution fMRI data with reliable data-driven analysis methods. The present study performed a detailed examination of dynamic changes of functional connectivity (FC) in a simple block-designed visual checkerboard experiment with a sub-second sampling rate (TR = 0.645 s) by estimating time-varying correlation coefficient (TVCC) between BOLD responses of different brain regions. We observed reliable task-related FC changes (i.e., FCs were transiently decreased after task onset and went back to the baseline afterward) among several visual regions of the bilateral middle occipital gyrus (MOG) and the bilateral fusiform gyrus (FuG). Importantly, only the FCs between higher visual regions (MOG) and lower visual regions (FuG) exhibited such dynamic patterns. The results suggested that simply assuming a sustained FC during a task block may be insufficient to capture distinct task-related FC changes. The investigation of FC dynamics in tasks could improve our understanding of condition shifts and the coordination between different activated brain regions

    Overexpression of soybean isoflavone reductase (GmIFR) enhances resistance to Phytophthora sojae in soybean

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    Isoflavone reductase (IFR) is an enzyme involved in the biosynthetic pathway of isoflavonoid phytoalexin in plants. IFRs are unique to the plant kingdom and are considered to have crucial roles in plant response to various biotic and abiotic environmental stresses. Here, we report the characterization of a novel member of the soybean isoflavone reductase gene family GmIFR. The cDNA of GmIFR was 1199 bp containing a 939 bp open reading frame encoding a polypeptide of 312 amino acids. Sequence analysis suggested that GmIFR contained a NAD(P) domain of 107 amino acids. Overexpression of GmIFR transgenic soybean exhibited enhanced resistance to Phytophthora sojae. Following stress treatments, GmIFR was significantly induced by P. sojae, ethephon (ET), abscisic acid (ABA), salicylic acid (SA). It is located in the cytoplasmic when transiently expressed in Arabidopsis protoplasts. The daidzein levels reduced greatly for the seeds of transgenic plants, while levels of genistein and glycitein had little change compared to that of control plants. Furthermore, we also found that the reactive oxygen species (ROS) content of transgenic soybean plants was significantly lower than that of control plants, suggesting an important role of GmIFR might function as an antioxidant to reduce ROS in soybean
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