Functional and structural specific roles of activity-driven BDNF within circuits formed by single spiny stellate neurons of the barrel cortex

Brain derived neurotrophic factor (BDNF) plays key roles in several neurodevelopmental disorders and actions of pharmacological treatments. However it is uncealr how specific BDNF’s effects are on diffeerent circuit components. Current studies have largely focused on the role of BDNF in modification of synaptic development. The precise roles of BDNF in the refinement of a functional circuit in vivo remain unclear. Val66Met polymorphism of BDNF may be associated with increased risk for cognitive impairments and is mediated at least in part by activity-dependent trafficking and/or secretion of BDNF. Using mutant mice that lacked activity-driven BDNF expression (bdnf-KIV), we previously reported that experience regulation of the cortical GABAergic network is mediated by activity-driven BDNF expression. Here, we demonstrate that activity-driven BDNF’s effects on circuits formed by the layer IV spiny stellate cells are highly specific. Structurally, dendritic but not axonal morphology was altered in the mutant. Physiologically, GABAergic but not glutamatergic synapses were severely affected. The effects on GABA transmission occurs via presynaptic alteration of calcium-dependent release probability. These results suggest that neuronal activity through activity-driven BDNF expression, can selectively regulate specific features of layer IV circuits in vivo. We postulate that the role of activity-dependent BDNF is to modulate the computational ability of circuits that relate to the gain control (i.e. feed-forward inhibition); whereas the basic wiring of circuits relevant to the sensory pathway is spared. Gain control modulation within cortical circuits has broad impact on cognitive processing and brain state-transitions. Cognitive behavior and mode is determined by brain states, thus the studying of circuit alteration by endogenous BDNF provides insights into the cellular and molecular mechanisms of diseases mediated by BDNF

Partitioning, repressing and derepressing: dynamic regulations in MLA immune receptor triggered defense signaling

Plants and animals have evolved intracellular nucleotide-binding (NB) domain and leucine-rich repeat (LRR)-containing immune receptors (NLRs) to perceive non-self and trigger immune responses. Plant NLRs detect strain-specific pathogen effectors and activate immune signaling leading to extensive transcriptional reprogramming and termination of pathogen infection. Here we review the recent findings in barley MLA immune receptor mediated immune responses against the barley powdery mildew fungus. We focus on nucleocytoplasmic partitioning of immune receptor, bifurcation of immune signaling, transcriptional repression and derepression connecting receptor activation to immune responses. We also discuss similar findings from other plant NLRs where appropriate

Mirror neuron system based therapy for aphasia rehabilitation

Objective: To investigate the effect of hand action observation training, i.e. mirror neuron system (MNS) based training, on language function of aphasic patients after stroke. In addition, to reveal the tentative mechanism underlying this effect.Methods: Six aphasic patients after stroke, meeting the criteria, undergo three weeks’ training protocol (30 min per day, 6 days per week). Among them, four patients accepted an ABA training design, i.e. they implemented Protocol A (hand action observation combined with repetition) in the first and third weeks while carried out Protocol B (static objects observation combined with repetition) in the second week. Conversely, for the other two patients, BAB training design was adopted, i.e. patients took Protocol B in the first and the third weeks and accepted Protocol A in the second week. Picture naming test, western aphasia battery (WAB) and Token Test were applied to evaluate the changes of language function before and after each week’s training. Furthermore, two subjects (one aphasic patient and one healthy volunteer) attended a functional MRI (fMRI) experiment, by which we tried to reveal the mechanism underlying possible language function changes after training.Results: Compared with static objects observation and repetition training (Protocol B), hand action observation and repetition training (Protocol A) effectively improved most aspects of the language function in all six patients, as demonstrated in the picture naming test, subtests of oral language and aphasia quotient(AQ) of WAB. In addition, the fMRI experiment showed that Protocol A induced more activations in the MNS of two participants when compared to Protocol B. Conclusion: The mirror neuron based therapy may facilitate the language recovery for aphasic patients and this to some extent provides a novel direction of rehabilitation for aphasia patients

Small RNA profiles of the rice PTGMS line Wuxiang S reveal miRNAs involved in the fertility transition

MicroRNAs (miRNAs) play key roles in the regulation of plant growth and developmental processes. In this study, the RNA-seq technique was employed to examine the expression profiles of miRNAs in a novel rice photo-thermo sensitive generic male sterile (PTGMS) line Wuxiang S (WXS) during the fertility transition. A total of 497 known miRNAs and 273 novel miRNAs were identified. By means of the differentially expression analysis, a total of 26 miRNAs were discovered to be significant difference expression between WXS (Sterility, S) and WXS (Fertility, F). And some of these miRNAs were validated by quantitative real-time PCR. Among these miRNAs, eleven of which were decreased, and fifteen of which were increased in the expression levels of genes when WXS (S) compared with WXS (F), respectively. Some of these miRNAs such as osa-miR156a-j, osa-miR164d and osa-miR528, were showed to be negatively correlated with their targets. These targets have previously been reported to be related with pollen development and male sterility, suggesting that these miRNAs might be involved in the regulation of pollen development in the rice PTGMS line WXS. Furthermore, the miRNAs editing events were also observed. A possible control model of miRNAs and signaling pathway was proposed in the process of fertility transition of rice PTGMS line WXS in this study. These findings contribute to our understanding of the roles of miRNAs during anther development of PTGMS occurrence in rice

Microbial community changes along the active seepage site of one cold seep in the Red Sea

The active seepage of the marine cold seeps could be a critical process for the exchange of energy between the submerged geosphere and the sea floor environment through organic-rich fluids, potentially even affecting surrounding microbial habitats. However, few studies have investigated the associated microbial community changes. In the present study, 16S rRNA genes were pyrosequenced to decipher changes in the microbial communities from the Thuwal seepage point in the Red Sea to nearby marine sediments in the brine pool, normal marine sediments and water, and benthic microbial mats. An unexpected number of reads from unclassified groups were detected in these habitats; however, the ecological functions of these groups remain unresolved. Furthermore, ammonia-oxidizing archaeal community structures were investigated using the ammonia monooxygenase subunit A (amoA) gene. Analysis of amoA showed that planktonic marine habitats, including seeps and marine water, hosted archaeal ammonia oxidizers that differed from those in microbial mats and marine sediments, suggesting modifications of the ammonia oxidizing archaeal communities along the environmental gradient from active seepage sites to peripheral areas. Changes in the microbial community structure of ammonia oxidizing archaea in different habitats (water versus sediment) potentially correlated with changes in salinity and oxygen concentrations. Overall, the present results revealed for the first time unanticipated novel microbial groups and changes in the ammonia-oxidizing archaea in response to environmental gradients near the active seepages of a cold seep

Rice gall dwarf virus exploits tubules to facilitate viral spread among cultured insect vector cells derived from leafhopper Recilia dorsalis

Rice gall dwarf virus (RGDV), a member of the family Reoviridae, causes repeated epidemics in rice fields in southern China. An RGDV isolate collected from Guangdong Province (southern China) is mainly transmitted by leafhopper vector Recilia dorsalis in a persistent-propagative manner. The infection by RGDV induces the formation of virus-containing tubules in the plant host and insect vector. In this study, we established continuous cell cultures of the leafhopper R. dorsalis to investigate the functional role of these tubules within the insect vector. Cytopathologic studies revealed that the tubules, which comprised viral nonstructural protein Pns11 and contained viral particles, were able to protrude from the surface of cultured leafhopper cells. Tubule-like structures formed in nonhost insect cells after the expression of Pns11 in a baculovirus system, suggesting that Pns11 was the minimal viral factor required for the formation of the tubules induced by RGDV infection. In cultured leafhopper cells, knockdown of Pns11 expression from RNA interference, induced by synthesized dsRNA from the Pns11 gene, abolished the formation of such tubules, preventing the direct cell-to-cell spread of RGDV without significant effects on viral multiplication. All these results show that RGDV exploits virus-containing tubules to facilitate viral spread among its insect vector cells

Involvement of calmodulin in regulation of primary root elongation by N-3-oxo-hexanoyl homoserine lactone in Arabidopsis thaliana

Many bacteria use signal molecules of low molecular weight to monitor their local population density and to coordinate their collective behavior in a process called quorum sensing (QS). N-acyl-homoserine lactones (AHLs) are the primary QS signals among Gram-negative bacteria. AHL-mediated QS plays an essential role in diverse bacterial physiological processes. Recent evidence shows that plants are able to sense bacterial AHLs and respond to them appropriately. However, little is known about the mechanism by which plants perceive and transduce the bacterial AHLs within cells. In this study, we found that the stimulatory effect of N-3-oxo-hexanoyl homoserine lactone (3OC6-HSL) on primary root elongation of Arabidopsis was abolished by the calmodulin (CaM) antagonists N-(6-aminohexyl)-5-chloro-1-naphthalene sulfonamide (W-7) and trifluoperazine (TFP). Western-blot and ELISA analysis revealed that the concentration of CaM protein in Arabidopsis roots increased after treatment with 1 μM 3OC6-HSL. Results from quantitative RT-PCR demonstrated that the transcription of all nine CaM genes in Arabidopsis genome was up-regulated in the plants treated with 3OC6-HSL. The loss-of-function mutants of each AtCaM gene (AtCaM1-9) were insensitive to 3OC6-HSL-stimulation of primary root elongation. On the other hand, the genetic evidence showed that CaM may not participates the inhibition of primary root length caused by application of long-chained AHLs such as C10-HSL and C12-HSL. Nevertheless, our results suggest that CaM is involved in the bacterial 3OC6-HSL signaling in plant cells. These data offer new insight into the mechanism of plant response to bacterial QS signals

Genome-wide Transcriptional Excavation of Dipsacus asperoides Unmasked both Cryptic Asperosaponin Biosynthetic Genes and SSR Markers

Background: Dipsacus asperoides is a traditional Chinese medicinal crop. The root is generally used as a medicine and is frequently prescribed by Chinese doctors for the treatment of back pain, limb paralysis, flutter trauma, tendon injuries and fractures. With the rapid development of bioinformatics, research has been focused on this species at the gene or molecular level. For purpose of fleshing out genome information about Dipsacus asperoides, in this paper we conducted transcriptome analysis of this species.Principal Findings: To date, many genes encoding enzymes involved in the biosynthesis of triterpenoid saponins in D.asperoides have not been elucidated. Illumina paired-end sequencing was employed to probe Dipsacus asperoides’s various enzymes associated with the relevant mesostate. A total of 30, 832,805 clean reads and de novo spliced 43,243 unigenes were obtained. Of all unigenes, only 8.27% (3578) were successfully annotated in total of seven public databases: Nr, Nt, Swiss-Prot, GO, KOG, KEGG and Pfam, which might be attributed to the poor studies on D. asperoides. The candidate genes encoding enzymes involved in triterpenoid saponin biosynthesis were identified and experimentally verified by reverse transcription qPCR, encompassing nine cytochrome P450s and seventeen UDP - glucosyltransferases. Specifically, unearthly putative genes involved in the glycosylation of hederagenin were acquired. Simultaneously, 4490 SSRs from 43,243 examined sequences were determined via bioinformatics analysis.Conclusion: This study represents the first report on the use of the Illumina sequence platform on this crop at the transcriptome level. Our findings of candidate genes encoding enzymes involved in Dipsacus saponin VI biosynthesis provide novel information in efforts to further understand the triterpenoid metabolic pathway on this species. The initial genetics resources in this study will contribute significantly to the genetic breeding program of Dipsacus asperoides, and are beneficial for clinical diagnosis and treatment

Integration of a decrescent transcriptome and metabolomics dataset of Peucedanum praeruptorum to investigate the CYP450 and MDR genes involved in coumarins biosynthesis and transport

Abstract Peucedanum praeruptorum Dunn is well-known traditional Chinese medicine. However, little is known in the biosynthesis and the transport mechanisms of its coumarin compounds at the molecular level. Although transcriptomic sequence is playing an increasingly significant role in gene discovery, it is not sufficient in predicting the specific function of target gene. Furthermore, there is also a huge database to be analyzed. In this study, RNA sequencing assisted transcriptome dataset and high-performance liquid chromatography (HPLC) coupled with electrospray-ionization quadrupole time-of-flight mass spectrometry (Q-TOF MS)-based metabolomics dataset of P. praeruptorum were firstly constructed for gene discovery and compound identification. Subsequently, methyl jasmonate (MeJA)-induced gene expression analysis and metabolomics analysis were conducted to narrow-down the dataset for selecting the candidate genes and the potential marker metabolites. Finally, the genes involved in coumarins biosynthesis and transport were predicted with parallel analysis of transcript and metabolic profiles. As a result, a total of 40952 unigenes and 19 coumarin compounds were obtained. Based on the results of gene expression and metabolomics analysis, 7 cytochrome-P450 and 8 multidrug resistance transporter unigenes were selected as candidate genes and 8 marker compounds were selected as biomarkers, respectively. The parallel analysis of gene expression and metabolites accumulation indicated that the gene labeled as 23746, 228 and 30922 were related to the formation of the coumarin core compounds whereas 36276 and 9533 participated in the prenylation, hydroxylation, cyclization or structural modification. Similarly, 1462, 20815 and 15318 participated in the transport of coumarin core compounds while 124029 and 324293 participated in the transport of the modified compounds. This finding suggested that integration of a decrescent transcriptome and metabolomics dataset could largely narrow down the number of gene to be investigated and significantly improve the efficiency of functional gene predication. In addition, the large amount of transcriptomic data produced from P. praeruptorum and the genes discovered in this study would provide useful information in investigating the biosynthesis and transport mechanism of coumarins

Hepatotoxic potential of asarones: In vitro evaluation of hepatotoxicity and quantitative determination in herbal products

α and β asarones are natural constituents of some aromatic plants, especially species of the genus Acorus. In addition to beneficial properties of asarones, genotoxicity and carcinogenicity are also reported. Due to potential toxic effects of β-asarone, a limit of exposure from herbal products of approximately 2 μg/kg body weight/day has been set temporarily until a full benefit/risk assessment has been carried out by the European Medicines Agency. Therefore, it is important to monitor levels of β-asarone in herbal products. In this study, we developed a simple, rapid and validated GC-MS method for quantitative determination of asarones and applied it in 20 pediatric herbal products after detecting high concentrations of β-asarone in a product suspected to be implicated in hepatotoxicity in a 3 month old infant. Furthermore, targeted toxicological effects were further investigated in human hepatocytes (THLE-2 cells) by employing various in vitro assays, with the goal of elucidating possible mechanisms for the observed toxicity. Results showed that some of the products contained as much as 4 to 25 times greater amounts of β-asarone than the recommended levels. In 4 of 10 samples found to contain asarones, the presence of asarones could not be linked to the labeled ingredients, possibly due to poor quality control. Cell-based investigations in THLE2 cells confirmed the cytotoxicity of -asarone (IC50 = 40.0 ± 2.0 µg/mL) which was associated with significant lipid peroxidation and glutathione depletion. This observed cytotoxicity effect is likely due to induction of oxidative stress by asarones. Overall, the results of this study ascertained the usability of this GC-MS method for the quantitative determination of asarones from herbal products, and shed light on the importance of controlling the concentration of potentially toxic asarones in herbal products to safeguard consumer safety. Further investigations of the toxicity of asarones are warranted