Chloroplasts are photosynthetic organelles derived from endosymbiotic cyanobacteria during evolution. Dramatic changes occurred
during the process of the formation and evolution of chloroplasts, including the large-scale gene transfer from chloroplast
to nucleus. However, there are still many essential characters remaining. For the chloroplast division machinery, FtsZ proteins,
Ftn2, SulA and part of the division site positioning system—MinD and MinE are still conserved. New or at least partially new
proteins, such as FtsZ family proteins FtsZ1 and ARC3, ARC6H, ARC5, PDV1, PDV2 and MCD1, were introduced for the division
of chloroplasts during evolution. Some bacterial cell division proteins, such as FtsA, MreB, Ftn6, FtsW and FtsI, probably
lost their function or were gradually lost. Thus, the chloroplast division machinery is a dynamically evolving structure with
both conservation and innovation. 相似文献
Chloroplasts are photosynthetic organelles derived from endosymbiotic cyanobacteria during evolution.Dramatic changes occurred during the process of the formation and evolution of chloroplasts,including the large-scale gene transfer from chloroplast to nucleus.However,there are still many essential characters remaining.For the chloroplast division machinery,FtsZ proteins,Ftn2,SulA and part of the division site positioning system- MinD and MinE are still conserved.New or at least partially new proteins,such as FtsZ family proteins FtsZl and ARC3,ARC6H,ARC5,PDV1,PDV2 and MCD1,were introduced for the division of chloroplasts during evolution.Some bacterial cell division proteins,such as FtsA,MreB,Ftn6,FtsW and Ftsl,probably lost their function or were gradually lost.Thus,the chloroplast division machinery is a dynamically evolving structure with both conservation and innovation. 相似文献
AMP‐activated protein kinase (AMPK) is an intracellular sensor of energy homoeostasis that is activated under energy stress and suppressed in energy surplus. AMPK activation leads to inhibition of anabolic processes that consume ATP. Osteogenic differentiation is a process that highly demands ATP during which AMPK is inhibited. The bone morphogenetic proteins (BMPs) signalling pathway plays an essential role in osteogenic differentiation. The present study examines the inhibitory effect of metformin on BMP signalling, osteogenic differentiation and trauma‐induced heterotopic ossification. Our results showed that metformin inhibited Smad1/5 phosphorylation induced by BMP6 in osteoblast MC3T3‐E1 cells, concurrent with up‐regulation of Smad6, and this effect was attenuated by knockdown of Smad6. Furthermore, we found that metformin suppressed ALP activity and mineralization of the cells, an event that was attenuated by the dominant negative mutant of AMPK and mimicked by its constitutively active mutant. Finally, administration of metformin prevented the trauma‐induced heterotopic ossification in mice. In conjuncture, AMPK activity and Smad6 and Smurf1 expression were enhanced by metformin treatment in the muscle of injured area, concurrently with the reduction of ALK2. Collectively, our study suggests that metformin prevents heterotopic ossification via activation of AMPK and subsequent up‐regulation of Smad6. Therefore, metformin could be a potential therapeutic drug for heterotopic ossification induced by traumatic injury. 相似文献
Purine pathway in Rhizobium is important during the nodulation processes. The purL gene in Sinorhizobium fredii (S. fredii) has been identified to be required for the whole establishment of a nitrogen-fixing nodule. To get a better understanding
of the purL gene’s impacts on Rhizobium–plant interaction, the competitive nodulation abilities of S. fredii containing different purL expression plasmids were studied. Several kinds of coinoculations were performed, including using different bacterial concentration
ratios, with or without the supplementation of purine source in the plant nutrient solution, and the delayed coinoculation
tests. The results indicated that the competitive nodule occupancy of S. fredii was affected significantly by the purL expression level during the early nodulation periods. The mutant strain containing no purL expression could not elicit competitive nodules both in the presence and absence of purine source. A positive linear correlation
within certain limits was observed between strain’s competitive nodule occupancy and purL gene expression level. All these results suggested that the purL gene played a role in the competitive nodulation of S. fredii. 相似文献
Growth differentiation factor 15 (GDF15), a direct target gene of p53, is a multifunctional member of the TGF-β/BMP superfamily. GDF15 can be induced and is implicated as a key secretory cytokine in response to multiple cellular stimuli. Accumulating evidence indicates that GDF15 is associated with the development and prognosis of diabetes mellitus, while whether GDF15 can be induced by high glucose is unknown. In the present study, we revealed that high glucose could induce GDF15 expression and secretion in cultured human umbilical vein endothelial cells in a ROS- and p53-dependent manner. Inhibition of high glucose-induced GDF15 expression by siRNA demonstrated that adaptively induced GDF15 played a protective role against high glucose-induced human umbilical vein endothelial cell apoptosis via maintaining the active state of PI3K/Akt/eNOS pathway and attenuating NF-κB/JNK pathway activation. The protective effects of GDF15 were probably achieved by inhibiting ROS overproduction in high glucose-treated human umbilical vein endothelial cells in a negative feedback manner. Our results suggest that high glucose can promote GDF15 expression and secretion in human umbilical vein endothelial cells, which in turn attenuates high glucose-induced endothelial cell apoptosis. 相似文献
Mycobacterium goodii X7B, which had been primarily isolated as a bacterial strain capable of desulfurizing dibenzothiophene to produce 2-hydroxybiphenyl via the 4S pathway, was also found to desulfurize benzothiophene. The desulfurization product was identified as o-hydroxystyrene by gas chromatography (GC)-mass spectrometry analysis. This strain appeared to have the ability to remove organic sulfur from a broad range of sulfur species in gasoline. When Dushanzi straight-run gasoline (DSRG227) containing various organic sulfur compounds was treated with immobilized cells of strain X7B for 24 h, the total sulfur content significantly decreased, from 227 to 71 ppm at 40°C. GC flame ionization detection and GC atomic emission detection analysis were used to qualitatively evaluate the effects of M. goodii X7B treatment on the contents of gasoline. In addition, when immobilized cells were incubated at 40°C with DSRG275, the sulfur content decreased from 275 to 54 ppm in two consecutive reactions. With this excellent efficiency, strain X7B is considered a good potential candidate for industrial applications for the biodesulfurization of gasoline. 相似文献
The objective of this study was to investigate the potential of Rhodopseudomonas palustris G5 in promoting growth and inducing salt resistance in cucumber (Cucumis sativus L.). In this study, the growth-promoting potential of the bacteria was studied by measuring the ability to produce indole-3-acetic acid (IAA) and 5-aminolevulinic acid (ALA), fix nitrogen, and solubilize potassium and phosphate. The greenhouse pot experiments were set up to study how strain G5 affected growth and salt resistance of cucumber seedlings. The results showed that strain G5 exhibited plant growth-promoting attributes such as the production of IAA and ALA, as well as nitrogen-fixing, potassium-solubilizing, and phosphorus-solubilizing ability. In pot trials, strain G5 increased shoot height, root length, fresh weight, dry weight, total chlorophyll content, and soluble sugar content of cucumber seedlings under salt stress, compared to the seedlings that were exposed to salt stress in the absence of the strain G5. Furthermore, antioxidant enzyme activity analysis showed that strain G5 strongly increased the activity of superoxide dismutase, peroxidase, and polyphenol oxidase in cucumber seedlings under salt stress. In addition, strain G5 treatment decreased H2O2 and malondialdehyde contents of salt-stressed seedling. In sum, these results showed that strain G5 enhanced growth and induced systemic resistance in cucumber seedlings under salt stress by the production of IAA, ALA, and soluble sugars, the induction of antioxidant enzymes as well as nutrient adjustment of nitrogen, phosphorus, and potassium.