Responses of beneficial Bacillus amyloliquefaciens SQR9 to different soilborne fungal pathogens through the alteration of antifungal compounds production

AbstractBacillus amyloliquefaciens SQR9 exhibited predominantly antagonistic activities against a broad range of soilborne pathogens. The fungi-induced SQR9 extracts possess stronger antifungal activities compared with SQR9 monoculture extracts. To investigate how SQR9 fine-tunes lipopeptides (LPs) and a siderophore bacillibactin production to control different fungal pathogens, LPs and bacillibactin production and transcription of the respective encoding genes in SQR9 were measured and compared with six different soilborne fungal pathogens. SQR9 altered its spectrum of antifungal compounds production responding to different fungal pathogen. Bacillomycin D was the major LP produced when SQR9 was confronted with Fusarium oxysporum. Fengycin contributed to the antagonistic activity against Verticillium dahliae kleb, Fusarium oxysporum, Fusarium solani and Phytophthora parasitica. Surfactin participated in the antagonistic process against Sclerotinia sclerotiorum, Rhizoctonia solani and Fusarium solani. Bacillibactin was up-regulated when SQR9 was confronted with all tested fungi. The reduction in antagonistic activities of three LP and bacillibactin deficient mutants of SQR9 when confronted with the six soilborne fungal pathogens provided further evidence of the contribution of LPs and bacillibactin in controlling fungal pathogens. These results provide a new understanding of specific cues in bacteria-fungi interactions and provide insights for agricultural applications

Syllable structure universals and native language interference in second language perception and production: Positional asymmetry and perceptual links to accentedness

The present study investigated how syllable structure differences between the first Language (L1) and the second language (L2) affect L2 consonant perception and production at syllable-initial and syllable-final positions. The participants were Mandarin-speaking college students who studied English as a second language. Monosyllabic English words were used in the perception test. Production was recorded from each Chinese subject and rated for accentedness by two native speakers of English. Consistent with previous studies, significant positional asymmetry effects were found across speech sound categories in terms of voicing, places of articulation, and manner of articulation. Furthermore, significant correlations between perception and accentedness ratings were found at the syllable onset position but not for the coda. Many exceptions were also found, which could not be solely accounted for by differences in L1-L2 syllabic structures. The results show a strong effect of language experience at the syllable level, which joins force with acoustic, phonetic, and phonemic properties of individual consonants in influencing positional asymmetry in both domains of L2 segmental perception and production. The complexities and exceptions call for further systematic studies on the interactions between syllable structure universals and native-language interference and refined theoretical models to specify the links between perception and production in second language acquisition

The effect of aging in inhibitory control of major depressive disorder revealed by event-related potentials

Elderly depressed patients manifest pronounced executive dysfunction compared with younger subjects with depressive disorder. Aging-related brain changes may result in executive dysfunction in geriatric depression. We investigated the neural correlates of inhibitory control processing in depressed subjects at different ages using event-related potentials (ERPs). A equiprobable visual Go/Nogo task was used in 19 young (27.4 ± 5.0 years) and 18 elderly (70.8 ± 6.9 years) depressed subjects and their age-matched healthy controls (20 young subjects, 26.2 ± 3.7 years, and 18 elderly subjects, 68.1 ± 4.8 years). The responses were based on two types of equilateral triangular figures of upright (Go) and inverted triangle (Nogo). The elderly subjects exhibited later N2 and P3 latencies, and larger Go-N2 and P3 amplitudes, compared with the younger subjects. Further, the elderly controls displayed smaller P3 in the central and parietal regions, and yielded larger Nogo-P3 amplitude in the frontal region compared with younger controls. While the young depressed patients yielded smaller P3 amplitude than the controls across frontal, central and parietal regions, elderly depressed patients yielded smaller P3 than the elderly controls only in the frontal region. Our results suggest that the inhibitory control subprocesses are differentially affected by depression and aging. The stimulus response speed and the effort intensity of inhibition control are specifically impaired in the elderly depressed patients. And the diminished amplitudes of frontal P3 in the elderly depression imply a frontal dysfunction mechanism

Scalable and DiI-compatible optical clearance of the mammalian brain

Efficient optical clearance is fundamental for whole brain imaging. In particular, clearance of the brain without membrane damage is required for the imaging of lipophilic tracer-labeled neural tracts. Relying on an ascending gradient of fructose solutions, SeeDB can achieve sufficient transparency of the mouse brain while ensuring that the plasma membrane remains intact. However, it is challenging to extend this method to larger mammalian brains due to the extremely high viscosity of the saturated fructose solution. Here we report a SeeDB-derived optical clearing method, termed FRUIT, which utilizes a cocktail of fructose and urea. As demonstrated in the adult mouse brain, combination of these two highly water-soluble clearing agents exerts a synergistic effect on clearance. More importantly, the final FRUIT solution has low viscosity so as to produce transparency of the whole adult rabbit brain via arterial perfusion, which is impossible to achieve with a saturated fructose solution. In addition to good compatibility with enhanced yellow fluorescent protein, the cocktail also preserves the fluorescence of the lipophilic tracer DiI. This work provides a volume-independent optical clearing method which retains the advantages of SeeDB, particularly compatibility with lipophilic tracers

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

The structural connectivity pattern of the default mode network and its association with memory and anxiety

The default mode network (DMN) is one of the most widely studied resting state functional networks. The structural basis for the DMN is of particular interest and has been studied by several researchers using diffusion tensor imaging (DTI). Most of these previous studies focused on a few regions or white matter tracts of the DMN so that the global structural connectivity pattern and network properties of the DMN remain unclear. Moreover, evidences indicate that the DMN is involved in both memory and emotion, but how the DMN regulates memory and anxiety from the perspective of the whole DMN structural network remains unknown. We used multimodal neuroimaging methods to investigate the structural connectivity pattern of the DMN and the association of its network properties with memory and anxiety in 205 young healthy subjects. Using a probabilistic fiber tractography technique based on DTI data and graph theory methods, we constructed the global structural connectivity pattern of the DMN and found that memory quotient (MQ) score was significantly positively correlated with the global and local efficiency of the DMN whereas anxiety was found to be negatively correlated with the efficiency. The strong structural connectivity between multiple brain regions within DMN may reflect that the DMN has certain structural basis. Meanwhile, we found the network efficiency of the DMN were related to memory and anxiety measures, which indicated that the DMN may play a role in the memory and anxiety

Mismatch negativity (MMN) latency as a biomarker of amnestic mild cognitive impairment in Chinese rural elders

The aim was to evaluate the Mismatch Negativity (MMN) component, a correlate of the automatic detection of changes in the acoustic environment, in healthy adults and adults with aMCI. 43 mild amnestic cognitive impairment (aMCI) subjects and 43 healthy Chinese older adults were arranged into experimental group and control group respectively. Their MMN amplitude and latency were measured at the FZ, FCZ and CZ electrode sites under a passive auditory oddball task. The results showed that the latencies obtained from the FZ, FCZ and CZ electrode sites were significantly longer in the aMCI adults than in the control adults (P<0.01) while there were no significant differences in MMN amplitude between two groups(P＞0.05). The MMN latency was found to be a sensitive and specific biomarker of aMCI

Heterologous xylose isomerase pathway and evolutionary engineering improve xylose utilization in Saccharomyces cerevisiae

Xylose utilization is one key issue for the bioconversion of lignocelluloses. It is promising approach to engineer heterologous pathway for xylose utilization in Saccharomyces cerevisiae. Here, we constructed xylose-fermenting yeast SyBE001 by combinatorial fine-tuning the expression of XylA and endogenous XKS1. Overexpression of genes RKI1, RPE1, TKL1 and TAL1 in the non-oxidative pentose phosphate pathway in SyBE002 accelerated xylose utilization by 19%. By repetitive adaptation, the xylose utilization rate increased to about 10 folds in strain SyBE003 evolved from SyBE002. Gene expression analysis identified variety of genes with significantly different expressions in pentose phosphate pathway, glycolysis and tricarboxylic acid cycle in SyBE003

Exploration of microRNAs and their targets engaging in the resistance interaction between wheat and stripe rust

Wheat stripe rust, caused by Puccinia striiformis f. sp. tritici (Pst), is one of the most destructive diseases of wheat worldwide. miRNAs are important regulators, they play very central roles in plant organ development, vegetable phase change and defense responses. In this study, two miRNA libraries from wheat cultivar Xingzi 9104 (XZ) challenged with the avirulent Pst race CYR32 and sterile water were constructed, respectively. A total of 596 miRNA candidates were obtained. 420 wheat-specific candidate miRNAs were screened in adult plants challenged with Pst using microarray-based analyses. We analyzed the abundance of candidate miRNAs, and the levels of a subset of candidate miRNAs were determined by quantitative real time PCR (qRT-PCR). The qRT-PCR results indicated that some miRNAs were involved in the incompatible interaction between wheat and Pst. In addition, we identified some miRNAs differentially expressed in different leaves. Additionally, the target genes of wheat miRNAs were confirmed by using degradome sequencing technology. Most of the annotated target genes are related to signal transduction, energy metabolism, and other functions. We selected some target genes for relative expression analysis using qRT-PCR, and found that RabGAP/TBC domain-containing protein, zinc finger protein and Cysteine-rich receptor-like protein kinase 41 may play important role in the incompatible interaction between XZ and CYR32. Intriguingly, miRNAs and target gene seem to form a complicated regulation network that regulates the wheat-Pst interaction. Our data provide the foundation for evaluating the important regulatory roles of miRNAs in the wheat-Pst interaction

Novel evidence for within-species leaf economics spectrum at multiple spatial scales

Leaf economics spectrum (LES), characterizing covariation among a suite of leaf traits relevant to carbon and nutrient economics, has been examined largely among species but hardly within species. In addition, very little attempt has been made to examine whether the existence of LES depends on spatial scales. To address these questions, we quantified the variation and covariation of four leaf economic traits (specific leaf area, leaf dry matter content, leaf nitrogen and phosphorus contents) in a cosmopolitan wetland species (Phragmites australis) at three spatial (inter-regional, regional, and site) scales across most of the species range in China. The species expressed large intraspecific variation in the leaf economic traits at all of the three spatial scales. It also showed strong covariation among the four leaf economic traits across the species range. The coordination among leaf economic traits resulted in LES at all three scales and the environmental variables determining variation in leaf economic traits were different among the spatial scales. Our results provide novel evidence for within-species LES at multiple spatial scales, indicating that resource trade-off could also constrain intraspecific trait variation mainly driven by climatic and/or edaphic differences