BackgroundDeep brain stimulation (DBS) improves motor and non-motor symptoms in patients with Parkinson’s disease (PD). Researchers mainly investigated the motor networks to reveal DBS mechanisms, with few studies extending to other networks. This study aimed to investigate multi-network modulation patterns using DBS in patients with PD.MethodsTwenty-four patients with PD underwent 1.5 T functional MRI (fMRI) scans in both DBS-on and DBS-off states, with twenty-seven age-matched healthy controls (HCs). Default mode, sensorimotor, salience, and left and right frontoparietal networks were identified by using the independent component analysis. Power spectra and functional connectivity of these networks were calculated. In addition, multiregional connectivity was established from 15 selected regions extracted from the abovementioned networks. Comparisons were made among groups. Finally, correlation analyses were performed between the connectivity changes and symptom improvements.ResultsCompared with HCs, PD-off showed abnormal power spectra and functional connectivity both within and among these networks. Some of the abovementioned abnormalities could be corrected by DBS, including increasing the power spectra in the sensorimotor network and modulating the parts of the ipsilateral functional connectivity in different regions centered in the frontoparietal network. Moreover, the DBS-induced functional connectivity changes were correlated with motor and depression improvements in patients with PD.ConclusionDBS modulated the abnormalities in multi-networks. The functional connectivity alterations were associated with motor and psychiatric improvements in PD. This study lays the foundation for large-scale brain network research on multi-network DBS modulation.
The research on relationship between rhizosphere microbes and root exudates has a great significance on discussion of interaction between rhizosphere microbes and plants, as well as control of soil-borne diseases and insect pest. GC-MS was used to analyze changes of tobacco root exudates under the antagonistic action of tobacco bacterial wilt and black shank. It turned out that when pathogens of tobacco bacterial wilt and black shank in tobacco root microorganisms increase, tobacco root exudates augmented rapidly among of which organic acids have the biggest growth, followed by amines. When the pathogens of tobacco bacterial wilt and black shank are inhibited by the active substance of antagonistic antibacterial, 20-23 kinds of root exudates are added; besides, the content of 7 substances was reduced to 0. Another interesting finding was that the fluctuations of phthalic acid, isophthalic acid and benzoic acid, which have caused continuous cropping obstacles, were very distinct. The results of this study have provided novel clues for the exploration of continuous tobacco cropping obstacles and soil-borne diseases.
phenotypic plasticity has been studied in diaspore-dimorphic species, but no such study has been done on a diaspore-polymorphic species. Our aim was to determine the effects of abiotic and biotic factors on phenotypic plasticity of the diaspore-polymorphic cold desert annual Ceratocarpus arenarius. plants produced from dispersal units near the soil surface (a, basicarps) and at the middle (c) and upper (f) parts of the plant canopy were subjected to different levels of soil moisture, nutrient supply and intramorph and intermorph densities. Different levels of these biotic and abiotic factors resulted in significant variation in total plant mass, diaspore mass, mass allocation to stem and reproductive organs and total number and proportion of morphs a, c and f on an individual. The effect of stress on number and mass of a dispersal unit morph varied by treatment, with dispersal unit f having the highest CV and dispersal unit a the lowest. The success of this diaspore polymorphic species in its rainfall-unpredictable environment likely is enhanced by plasticity in production of the different types of diaspores. Fruit and seed heteromorphism is a phenomenon in which individual plants produce two or more kinds of diaspores that differ in size, mass, dispersal and dormancy 1 , and it may be a bet-hedging strategy that reduces the risk of failure under temporal environmental uncertainty 2. Phenotypic plasticity, the capability of a genotype to produce different phenotypes in different environmental conditions, is a common phenomenon in plants 3-6. It includes morphological 7-9 , physiological 10,11 and ecological 12,13 changes in the phenotype and can occur in both diaspore monomorphic and diaspore heteromorphic species. Plasticity in diaspore production has been studied in species with dimorphic aerial diaspores 1,14. These studies have shown that stress can increase 15-20 , decrease 21-23 or not change 24,25 the proportion of the two diaspores. However, little is known about plasticity of diaspore production in species with three (trimorphic) diaspore morphs 26-28 and even less about those with more than three (polymorphic) morphs 29-31. Further, no such studies have been done on an amphi-basicarpic species that produces polymorphic diaspores. The summer annual polymorphic species Ceratocarpus arenarius L. (Amaranthaceae) is native to middle and central Asia, and in China it grows only in the cold deserts of northern Xinjiang Province of NW China 32. Plants produce fruits (utricles) near the soil surface (basicarps) and a continuous series of morphologically distinct fruits from the lower to upper parts of the canopy. The (usually two) basicarps are designated as morph a and the canopy morphs b-f (from lower to upper part of canopy) (Fig. 1). Each fruit is covered by two bracteoles, and the fruit with these bracteoles is the dispersal and germination unit of the species. The number of aerial dispersal units per individual is 35-740, depending on plant size and habitat conditions (i.e. degree of stress) 33. Thus, C. a...
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