Growth response of broom (Cytisus scoparius) growing with and without radiata pine (Pinus radiata) seedlings to different P levels in soils

A study was carried out to test the effects of three rates of TSP （triple superphosphate） （0, 50, and 100 mg·kg^-1 P） on growth of broom with and without radiata pine seedlings and to determine the relationships between P concentrations in the broom shoot and dry matter yields with soil plant-available P （Bray-2 P）. A bulk sample of soil was collected from Kaweka forest at soil depth of 0-10 cm, in New Zealand on March 11, 2001. The forest area was not supplied with fertiliser at least 30 years. The results show that TSP application increased P avail- ability in the soil. The P availability concentration in soil of broom with radiata pine seedlings was higher than that in soil of broom alone. Bray-2 P concentrations had a significant logarithmic relationship with Pcon- centrations of broom shoot and an exponential relationship with dry matter weight of whole broom plant.

Global qualitative analysis of new Monod type chemostat model with delayed growth response and pulsed input in polluted environment

In this paper, we consider a new Monod type chemostat model with time delay and impulsive input concentration of the nutrient in a polluted environment. Using the discrete dynamical system determined by the stroboscopic map, we obtain a ＂microorganism-extinction＂ periodic solution. Further, we establish the sufficient conditions for the global attractivity of the microorganism-extinction periodic solution. Using new computational techniques for impulsive and delayed differential equation, we prove that the system is permanent under appropriate conditions. Our results show that time delay is ＂profitless＂.

Early Growth Response Gene-1 Deficiency Interrupts TGFβ1 Signaling Activation and Aggravates Neurodegeneration in Experimental Autoimmune Encephalomyelitis Mice

Early growth response protein 1(Egr-1)triggers the transcription of many genes involved in cell growth,differentiation,synaptic plasticity,and neurogenesis.However,its mechanism in neuronal survival and degeneration is still poorly understood.This study demonstrated that Egr-1 was down-regulated at mRNA and protein levels in the central nervous system(CNS)of experimental autoimmune encephalomyelitis(EAE)mice.Egr-1 knockout exacerbated EAE progression in mice,as shown by increased disease severity and incidence;it also aggravated neuronal apoptosis,which was associated with weakened activation of the BDNF/TGFβ1/MAPK/Akt signaling pathways in the CNS of EAE mice.Consistently,Egr-1 siRNA promoted apoptosis but mitigated the activation of BDNF/TGFβ1/MAPK/Akt signaling in SH-SY5Y cells.Our results revealed that Egr-1 is a crucial regulator of neuronal survival in EAE by regulating TGFβ1-mediated signaling activation,implicating the important role of Egr-1 in the pathogenesis of multiple sclerosis as a potential novel therapy target.

MiR-551b-5p Contributes to Pathogenesis of Vein Graft Failure via Upregulating Early Growth Response-1 Expression

Background： Vein graft failure （VGF） is a serious complication of coronary artery bypass graft, although the mechanism remains unclear. The study aimed to investigate the effects of microRNAs （miRNAs） on the endothelial dysfunction involved in VGF. Methods： Human umbilical vein endothelial cells （HUVECs） were subjected to mechanical stretch stimulation to induce endothelial dysfunction. Genome-wide transcriptome profiling was performed using the Human miRNA OneArray＂ V4 （PhalanxBio Inc., San Diego, USA）. The miRNA-messenger RNA （mRNA） network was investigated using gene ontology and Kyoto Encyclopedia of Genes and Genomes. The miR-55 1b-5p mimic and inhibitor were applied to regulate miR-55 lb-5p expression in the HUVECs. The 5-ethynyl-2＇-deoxyuridine assay, polymerase chain reaction （PCR）, and Western blotting （WB） were used to assess HUVECs proliferation, mRNA expression, and protein expression, respectively. The vein graft model was established in early growth response （Egr）-I knockout （KO） mice and wide-type （WT） C57BL/6J mice for pathological and immunohistochemical analysis. Endothelial cells isolated from the veins of WT and Egr-1 KO mice were subjected to mechanical stretch stimulation; PCR and WB were conducted to confirm the regulatory effect of Egr- 1 on Intercellular adhesion molecule （loam-1）. One-way analysis of variance and independent t-test were performed for data analysis. Results： Thirty-eight rniRNAs were differentially expressed in HUVECs after mechanical stretch stimulation. The bioinforrnatics analysis revealed that Egr-1 might be involved in VGF and was a potential target gene of miR-551b-5p. The mechanical stretch stimulation increased miR-55 1b-5p expression by 2.93 ± 0.08 told （t= 3.07, P 〈 0.05）, compared with the normal HUVECs. Transfection with the miR-551b-5p mimic or inhibitor increased expression of miR-551b-5p by 793.1 ± 171.6 fold （t = 13.84, P 〈 0.001） or decreased by 26.3% ± 2.4% （t= 26.39, P 〈 0.05） in the HUVECs, respectively. HUVECs proliferation and EGR-I mRNA expression were significantly suppressed by inhibiting miR-551b-5p expression （P 〈 0.05）. The lumens of the vein grafts in the Egr-1 KO mice were wider than that in the WT mice. lcam-I expression was suppressed significantly in the Egr-1 KO vein grafts （P 〈 0.05）. Conclusions： Increased miR-55 1b-5p expression leads to endothelial dysfunction by upregulating Egr-1 expression. EGR-1 KO can improve the function of a grafted vein through suppressing loam-1.

Lipocalin-2-Mediated Insufficient Oligodendrocyte Progenitor Cell Remyelination for White Matter Injury After Subarachnoid Hemorrhage via SCL22A17 Receptor/Early Growth Response Protein 1 Signaling

Insufficient remyelination due to impaired oligodendrocyte precursor cell(OPC)differentiation and maturation is strongly associated with irreversible white matter injury(WMI)and neurological deficits.We analyzed whole transcriptome expression to elucidate the potential role and underlying mechanism of action of lipocalin-2(LCN2)in OPC differentiation and WMI and identified the receptor SCL22A17 and downstream transcription factor early growth response protein 1(EGR1)as the key signals contributing to LCN2-mediated insufficient OPC remyelination.In LCN-knockdown and OPC EGR1 conditional-knockout mice,we discovered enhanced OPC differentiation in developing and injured white matter(WM);consistent with this,the specific inactivation of LCN2/SCl22A17/EGR1 signaling promoted remyelination and neurological recovery in both atypical,acute WMI due to subarachnoid hemorrhage and typical,chronic WMI due to multiple sclerosis.This potentially represents a novel strategy to enhance differentiation and remyelination in patients with white matter injury.

Control of tendon cell fate in the embryonic limb: A molecular perspective

The molecular cascade underlying tendon formation starts when progenitor cells begin to express the Scleraxis(Scx)gene.Scx knockout mice develop some but not all tendons,suggesting that additional factors are necessary for tendon commitment,maintenance,and differentiation.Other transcription factors,such as Mohawk(Mkx)or early growth response(Egr),maintain Scx expression and extracellular matrix formation during fibrillogenesis.The inhibition of wingless and int-related protein signaling is necessary and sufficient to induce the expression of Scx.Once the commitment of tenogenic lineage occurs,transforming growth factor-beta(TGFβ)induces the Scx gene expression,becoming involved in the maintenance of tendon cell fate.From this point of view,we discussed two phases of the tenogenic process during limb development:dependent and independent of mechanical forces.Finally,we highlight the importance of understanding embryonic tendon development to improve therapeutic strategies in regenerative medicines for tendons.

Hippocampal and thalamic neuronal metabolism in a putative rat model of schizophrenia°

The transcription factor early growth response protein 3 （EGR3） is involved in schizophrenia. We developed a putative rat model of schizophrenia by transfecting lentiviral particles carrying the Egr3 gene into bilateral hippocampal dentate gyrus. We assessed spatial working memory using the Morris water maze test, and neuronal metabolite levels in bilateral hippocampus and thalamus were determined by 3.0 T proton magnetic resonance spectroscopy. Choline content was significantly greater in the hippocampus after transfection, while N-acetylaspartate and the ratio of N-acetylaspartate to creatine/phosphocreatine in the thalamus were lower than in controls. This study is the first to report evaluation of brain metabolites using 3,0 T proton magnetic resonance spectroscopy in rats transfected with Egr3, and reveals metabolic abnormalities in the hippocampus and thalamus in this putative model of schizophrenia.

Alterations of Endogenous Hormonal Levels in Plants under Drought and Salinity

The phytohormones are pivotal chemical messengers produced within the plant that regulate its growth and development, and responses to environmental stimuli. Drought and salinity are adverse environmental factors that disturb the plant hormonal balance. Accordingly, these hormonal fluctuations modify the cellular dynamic and hence they play a central role in regulating plant growth responses to abiotic stresses such as drought and salinity. The present review gives an update about the alterations of endogenous phytohormones such as abscisic acid (ABA), auxins (Aux), cytokinins (CKs), ethylene (ET), gibberellins (GAs), jasmonates (JAs), salicylic acid (SA), brassinosteroids (BRs), strigolactones (SLs) and nitric oxide (NO) that occur as part of the adaptative responses of plant against drought and salt stresses. Better understanding of the endogenous hormonal changes during the plant response to both abiotic stresses will contribute, in part, to the development of stress-tolerant plants.

Research progress of the synapsin 2 gene polymorphism in the pathogenesis of schizophrenia

Schizophrenia(SCZ)is the most common serious mental illness with a high disability rate and heavy social and family burdens.At present,there is no clear etiology and pathogenesis of schizophrenia.Studies have shown that the occurrence of schizophrenia may be related to the abnormality of the hypothalamic-pituitary-adrenal(HPA)axis.The LIM-homeobox gene 3(LHXS)and early growth response 1(EGR1)can affect pituitary function.Because the synapsin 2(SYN2)gene polymorphism regulates the activity of LHX3 and EGR1,it may cause the occurrence of schizophrenia.This article will review the possible involvement of SYN2 gene polymorphism in the pathogenesis of schizophrenia via regulating the activity of LHX3 and EGR1,then to afiect the HPA axis.

Potassium channel AKT1 is involved in the auxin-mediated root growth inhibition in Arabidopsis response to low K^+stress

The changes in external K^＋ concentration affect plant root growth. However, the molecular mechanism for perceiving a K^＋ signal to modulate root growth remains unknown. It is hypothesized that the K^＋ channel AKTI is involved in low K^＋ sensing in the Arabidopsis root and subsequent regulation of root growth. Along with the decline of external K^＋ concentration, the primary root growth of wild-type plants was gradually inhibited. However, the primary root of the akt1 mutant could still grow under low K^＋（LK） conditions. Application of NAA inhibited akt1 root growth, but promoted wild-type root growth under LK conditions. By using the ProDR5：GFP and ProPIN1：PIN1-GFP lines, we found that LK treatment reduced auxin accumulation in wild-type root tips by degrading PIN1 proteins, which did not occur in the akt1 mutant. The LK-induced PIN1 degradation may be due to the inhibition of vesicle trafficking of PIN1 proteins. In conclusion, our findings indicate that AKT1 is required for an Arabidopsis response to changes in external K^＋, and subsequent regulation of K^＋-dependent root growth by modulating PINt degradation and auxin redistribution in the root.