A Study of Phytoplankton Community Structure in Duobukuer Nature Reserve

In spring,summer,autumn 2015,we studied the seasonal variation of phytoplankton community structure in six rivers within Duobukuer Nature Reserve,and made preliminary evaluation of the water quality in Duobukuer Nature Reserve based on phytoplankton diversity.The results showed that a total of 7 phyla,41 genera,66 species and varieties of phytoplankton were identified in Duobukuer Nature Reserve;the annual species composition was dominated by diatom( 59%) which also preponderated in dominant species( 84. 3%),biomass( 68%)and abundance( 75%),with no significant seasonal variation. Shannon-Wiener diversity index( H') and Pielou evenness index( J) were used to evaluate the water quality in 13 sampling points,and the results showed that the water quality was good in Duobukuer Nature Reserve,the sampling points 5,6 and 12 presented β-pollution,and other sampling points were in an oligosaprobic-clean state.

The DELLA-ABI4-HY5 module integrates light and gibberellin signals to regulate hypocotyl elongation

Plant growth is coordinately controlled by various environmental and hormonal signals,of which light and gibberellin(GA)signals are two critical factors with opposite effects on hypocotyl elongation.Although interactions between the light and GA signaling pathways have been studied extensively,the detailed regulatory mechanism of their direct crosstalk in hypocotyl elongation remains to be fully clarified.Previously,we reported that ABA INSENSITIVE 4(ABI4)controls hypocotyl elongation through its regulation of cellelongation-related genes,but whether it is also involved in GA signaling to promote hypocotyl elongation is unknown.In this study,we showthat promotion of hypocotyl elongation by GA is dependent on ABI4 activation.DELLAs interact directly with ABI4 and inhibit its DNA-binding activity.In turn,ABI4 combined with ELONGATED HYPOCOTYL 5(HY5),a key positive factor in light signaling,feedback regulates the expression of the GA2ox GA catabolism genes and thus modulates GA levels.Taken together,our results suggest that the DELLA-ABI4-HY5 module may serve as a molecular link that integrates GA and light signals to control hypocotyl elongation.

Regulatory dynamics of the higher-plant PSI-LHCI supercomplex during state transitions

State transition is a fundamental light acclimation mechanism of photosynthetic organisms in response to the environmental light conditions.This process rebalances the excitation energy between photosystemI(PSl)and photosystem Il through regulated reversible binding of the light-harvesting complex Il(LHCll)to PSl.However,the structural reorganization of PSI-LHCI,the dynamic binding of LHCll,and the regulatory mechanisms underlying state transitions are less understood in higher plants.In this study,using cryoelectron microscopy we resolved the structures of PSI-LHCI in both state 1(PSI-LHCI-ST1)and state 2(PSILHCI-LHCll-ST2)from Arabidopsis thaliana.Combined genetic and functional analyses revealed novel contacts between Lhcb1 and PsaK that further enhanced the binding of the LHCll trimer to the PSI core with the known interactions between phosphorylated Lhcb2 and the PsaL/PsaH/PsaO subunits.Specifically,PsaO was absent in the PSI-LHCI-ST1 supercomplex but present in the PSI-LHCI-LHCIl-ST2 supercomplex,in which the PsaL/PsaK/PsaA subunits undergo several conformational changes to strengthen the binding of PsaO in ST2.Furthermore,the PSI-LHCI module adopts a more compact configuration with shorter Mg-to-Mg distances between the chlorophylls,which may enhance the energy transfer efficiency from the peripheral antenna to the PSl core in ST2.Collectively,our work provides novel structural and functional insights into the mechanisms of light acclimation during state transitions in higher plants.

Research Progress of Acupuncture Treatment of Neurogenic Bladder after Spinal Cord Injury

Neurogenic bladder (NB) mainly occurs in patients with spinal cord injury (SCI). The pathological basis of NB is the occurrence of lesions in the urination control center, which requires systematic treatment. Western medicine has many treatment methods for this disease, which can alleviate the symptoms of the disease. However, the radical effect is not ideal and there are many adverse reactions. In comparison, acupuncture can improve the residual urine volume of NB patients and regulate the related indexes of urodynamics. There are many kinds of acupuncture therapies, such as simple acupuncture and moxibustion, which can comprehensively improve the therapeutic effect and obtain a better disease prognosis. Therefore, this article elaborates on the pathogenesis of SCI complicated with NB, the treatment mechanism, and treatment methods of acupuncture and moxibustion to provide a reference for clinical treatment.

Phase separation in plants:New insights into cellular compartmentalization

A fundamental challenge for cells is how to coordinate various biochemical reactions in space and time. To achieve spatiotemporal control, cells have developed organelles that are surrounded by lipid bilayer membranes. Further, membraneless compartmentalization, a process induced by dynamic physical association of biomolecules through phase transition offers another efficient mechanism for intracellular organization. While our understanding of phase separation was predominantly dependent on yeast and animal models, recent findings have provided compelling evidence for emerging roles of phase separation in plants. In this review, we first provide an overview of the current knowledge of phase separation, including its definition, biophysical principles, molecular features and regulatory mechanisms. Then we summarize plant-specific phase separation phenomena and describe their functions in plant biological processes in great detail. Moreover, we propose that phase separation is an evolutionarily conserved and efficient mechanism for cellular compartmentalization which allows for distinct metabolic processes and signaling pathways, and is especially beneficial for the sessile lifestyle of plants to quickly and efficiently respond to the changing environment.

A Kinase-Phosphatase-Transcription Factor Module Regulates Adventitious Root Emergence in Arabidopsis Root-Hypocotyl Junctions

Adventitious roots form from non-root tissues as part of normal development or in response to stress or wounding.The root primordia form in the source tissue,and during emergence the adventitious roots penetrate the inner cell layers and the epidermis;however,the mechanisms underlying this emergence remain largely unexplored.Here,we report that a regulatory module composed of the AP2/ERF transcription factor ABSCISIC ACID INSENSITIVE 4(ABI4),the MAP kinases MPK3 and MPK6,and the phosphatase PP2C12 plays an important role in the emergence of junction adventitious roots(J-ARs)from the root-hypocotyl junctions in Arabidopsis thaliana.ABI4 negatively regulates J-AR emergence,preventing the accumulation of reactive oxygen species and death of epidermal cells,which would otherwise facilitate J-AR emergence.Phosphorylation by MPK3/MPK6 activates ABI4 and dephosphorylation by PP2C12 inactivates ABI4.MPK3/MPK6 also directly phosphorylate and inactivate PP2C12 during J-AR emergence.We propose that this"double-check"mechanism increases the robustness of MAP kinase signaling and finely regulates the local programmed cell death required for J-AR emergence.