scholarly journals AbhemC encoding porphobilinogen deaminase plays an important role in chlorophyll biosynthesis and function in albino Ananas comosus var. bracteatus leaves

PeerJ ◽  
2021 ◽  
Vol 9 ◽  
pp. e11118
Author(s):  
Yanbin Xue ◽  
Xia Li ◽  
Meiqin Mao ◽  
Yehua He ◽  
Mark Owusu Adjei ◽  
...  
Keyword(s):  
Enzyme Activity ◽  
Chlorophyll Biosynthesis ◽  
Underlying Mechanism ◽  
Ananas Comosus ◽  
Porphobilinogen Deaminase ◽  
Chl A ◽  
Prokaryotic Protein ◽  
And Function ◽  
Chl Biosynthesis

Background The chimeric leaves of Ananas comosus var. bracteatus are composed of normal green parts (Grs) and albino white parts (Whs). Although the underlying mechanism of albinism in A. comosus var. bracteatus leaves is not fully understood, it is likely associated with the chlorophyll (Chl) biosynthesis. In this biosynthetic process, porphobilinogen deaminase (PBGD) plays a crucial role by catalyzing the conversion of porphobilinogen (PBG) to uroporphyrinogen III (Urogen III). Therefore, its encoding gene AbhemC was investigated here in association with Chl biosynthesis and albinism in chimeric A. comosus var. bracteatus leaves. Methods The Chl content, main Chl biosynthesis precursor content, and main enzyme activity were determined and compared between the Whs and Grs of A. comosus var. bracteatus leaves. In addition, AbhemC was cloned and its transcriptional expression and prokaryotic protein expression were analyzed. Furthermore, RNAi-mediated silencing of AbhemC was produced and assessed in tobacco plants. Results The concentration of Chl a and Chl b in the Grs was significantly higher than that in the Whs, respectively. Additionally, the content of the Chl biosynthesis precursor Urogen III decreased significantly in the Whs compared with the Grs. Thus, the transition of PBG to Urogen III may be the first rate-limiting step leading to albinism in the chimeric leaves of A. comosus var. bracteatus. The gene AbhemC comprised 1,135 bp and was encoded into a protein with 371 amino acids; phylogenetically, AbhemC was most closely related to hemC of pineapple. Prokaryotic expression and in vitro enzyme activity analysis showed that the cloned mRNA sequence of AbhemC was successfully integrated and had PBGD activity. Compared with control plants, transgenic tobacco leaves with pFGC5941-AbhemC-RNAi vector were substantially less green with significantly reduced hemC expression and Chl content, as well as reduced PBGD enzyme activity and significantly decreased content of Chl biosynthesis precursors from Urogen III onwards. Our results suggest that the absence of hemC expression reduces the enzyme activity of PBGD, which blocks the transition of PBG to Urogen III, and in turn suppresses Chl synthesis leading to the pale-green leaf color. Therefore, we suggest that AbhemC plays an important role in Chl synthesis and may be an important factor in the albinism of A. comosus var. bracteatus leaves.

scholarly journals Transcription Profile Analysis of Chlorophyll Biosynthesis in Leaves of Wild-Type and Chlorophyll b-Deficient Rice (Oryza sativa L.)

Agriculture ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 401
Author(s):  
Minh Khiem Nguyen ◽  
Tin-Han Shih ◽  
Szu-Hsien Lin ◽  
Jun-Wei Lin ◽  
Hoang Chinh Nguyen ◽  
...  
Keyword(s):  
Oryza Sativa ◽  
Core Protein ◽  
Profile Analysis ◽  
Oryza Sativa L ◽  
Electron Flow ◽  
Chlorophyll Biosynthesis ◽  
Wild Type ◽  
Transcription Analysis ◽  
Chl A ◽  
Chl Biosynthesis

Photosynthesis is an essential biological process and a key approach for raising crop yield. However, photosynthesis in rice is not fully investigated. This study reported the photosynthetic properties and transcriptomic profiles of chlorophyll (Chl) b-deficient mutant (ch11) and wild-type rice (Oryza sativa L.). Chl b-deficient rice revealed irregular chloroplast development (indistinct membranes, loss of starch granules, thinner grana, and numerous plastoglobuli). Next-generation sequencing approach application revealed that the differential expressed genes were related to photosynthesis machinery, Chl-biosynthesis, and degradation pathway in ch11. Two genes encoding PsbR (PSII core protein), FtsZ1, and PetH genes, were found to be down-regulated. The expression of the FtsZ1 and PetH genes resulted in disrupted chloroplast cell division and electron flow, respectively, consequently reducing Chl accumulation and the photosynthetic capacity of Chl b-deficient rice. Furthermore, this study found the up-regulated expression of the GluRS gene, whereas the POR gene was down-regulated in the Chl biosynthesis and degradation pathways. The results obtained from RT-qPCR analyses were generally consistent with those of transcription analysis, with the exception of the finding that MgCH genes were up-regulated which enhance the important intermediate products in the Mg branch of Chl biosynthesis. These results indicate a reduction in the accumulation of both Chl a and Chl b. This study suggested that a decline in Chl accumulation is caused by irregular chloroplast formation and down-regulation of POR genes; and Chl b might be degraded via the pheophorbide b pathway, which requires further elucidation.

scholarly journals Biochemical and genetic analysis of Ecm14, a conserved fungal pseudopeptidase

2020 ◽  
Author(s):  
R Christian McDonald ◽  
Matthew J Schott ◽  
Temitope A Idowu ◽  
Peter J Lyons
Keyword(s):  
Enzyme Activity ◽  
Large Scale ◽  
Structure And Function ◽  
Activation Mechanism ◽  
Marker Genes ◽  
Synthetic Lethal ◽  
Fungal Process ◽  
And Function

Abstract Background. Like most major enzyme families, the M14 family of metallocarboxypeptidases (MCPs) contains a number of pseudoenzymes predicted to lack enzyme activity and with poorly characterized molecular function. The genome of the yeast Saccharomyces cerevisiae encodes one member of the M14 MCP family, a pseudoenzyme named Ecm14 proposed to function in the extracellular matrix. In order to better understand the function of such pseudoenzymes, we studied the structure and function of Ecm14 in S. cerevisiae. Results. A phylogenetic analysis of Ecm14 in fungi found it to be conserved throughout the ascomycete phylum, with a group of related pseudoenzymes found in basidiomycetes. To investigate the structure and function of this conserved protein, His6-tagged Ecm14 was overexpressed in Sf9 cells and purified. The prodomain of Ecm14 was cleaved in vivo and in vitro by endopeptidases, suggesting an activation mechanism; however, no activity was detectable using standard carboxypeptidase substrates. In order to determine the function of Ecm14 using an unbiased screen, we undertook a synthetic lethal assay. Upon screening approximately 27,000 yeast colonies, twenty-two putative synthetic lethal clones were identified. Further analysis showed many to be synthetic lethal with auxotrophic marker genes and requiring multiple mutations, suggesting that there are few, if any, single S. cerevisiae genes that present synthetic lethal interactions with ecm14Δ. Conclusions. We show in this study that Ecm14, although lacking detectable enzyme activity, is a conserved carboxypeptidase-like protein that is secreted from cells and is processed to a mature form by the action of an endopeptidase. Our study and datasets from other recent large-scale screens suggest a role for Ecm14 in processes such as vesicle-mediated transport and aggregate invasion, a fungal process that has been selected against in modern laboratory strains of S. cerevisiae.

scholarly journals Temperature-mediated shifts in chlorophyll biosynthesis in leaves of chlorophyll b-lacking rice (Oryza sativa L.)

2021 ◽  
Vol 49 (2) ◽  
pp. 12306
Author(s):  
Khiem Minh NGUYEN ◽  
Zhi-Wei YANG ◽  
Tin-Han SHIH ◽  
Szu-Hsien LIN ◽  
Jun-Wei LIN ◽  
...  
Keyword(s):  
Crop Yields ◽  
Oryza Sativa L ◽  
Chlorophyll Biosynthesis ◽  
Differentially Expressed Gene ◽  
Growth And Yield ◽  
Light Harvesting Complex ◽  
Chl A ◽  
Light Harvesting Complex Ii ◽  
Influence Of Temperature On ◽  
Chl Biosynthesis

Extreme temperatures have become a threat to crop yields. To maintain plant growth and yield, chlorophyll (Chl) biosynthesis plays a crucial role in adaptation to temperature stress. This study investigated the influence of temperature on the biosynthesis and characteristics of pigments (Chl a, Chl b, and carotenoids) in the leaves of Chl b-lacking mutant rice (Chlorina 1, ch1) and wild-type rice (Norin No.8, wt). The ch1 showed thinner stacked grana caused by a decrease in thylakoid membranes per granum at 15 °C, whereas the destacked grana were observed at 35 °C after 12 h incubation. However, the grana are stacked normally, along with the absence of Chl b, and a significantly decreased amount of Chl a in both wt and ch1 were observed after heat stress exposure, demonstrating that light-harvesting complex II proteins are involved in grana stacking. Ch1 was sensitive to 15 °C during the first 4 h of incubation but it subsequently adapted to the cold environment. In addition, there were no significant differences in the photosynthesis between wt and ch1 after 12 h incubation at 35 °C. Differentially expressed gene (DEGs) analysis revealed that GluRS expression decreased, which resulted in a decline in Chl biosynthesis in wt and ch1 at 35 °C. At 8 h and 12 h, there were no significant differences in the expression of DEGs involved in Chl biosynthesis and degradation between wt and ch1 at 15 °C. ALAD expression in wt and ch1 at 15 °C decreased until it was undetectable. These findings suggested that ch1 may adapt to temperatures ranging from 15 °C to 35 °C.

scholarly journals Specific effects of antitumor active norspermidine on the structure and function of DNA

2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Takashi Nishio ◽  
Yuko Yoshikawa ◽  
Chwen-Yang Shew ◽  
Naoki Umezawa ◽  
Tsunehiko Higuchi ◽  
...  
Keyword(s):  
Gene Expression ◽  
Cell Function ◽  
Specific Effect ◽  
Underlying Mechanism ◽  
Chemical Structures ◽  
Specific Effects ◽  
Methylene Groups ◽  
And Function ◽  
Dna Measurements

Abstract We compared the effects of trivalent polyamines, spermidine (SPD) and norspermidine (NSPD), a chemical homologue of SPD, on the structure of DNA and gene expression. The chemical structures of SPD and NSPD are different only with the number of methylene groups between amine groups, [N-3-N-4-N] and [N-3-N-3-N], respectively. SPD plays vital roles in cell function and survival, including in mammals. On the other hand, NSPD has antitumor activity and is found in some species of plants, bacteria and algae, but not in humans. We found that both polyamines exhibit biphasic effect; enhancement and inhibition on in vitro gene expression, where SPD shows definitely higher potency in enhancement but NSPD causes stronger inhibition. Based on the results of AFM (atomic force microscopy) observations together with single DNA measurements with fluorescence microscopy, it becomes clear that SPD tends to align DNA orientation, whereas NSPD induces shrinkage with a greater potency. The measurement of binding equilibrium by NMR indicates that NSPD shows 4–5 times higher affinity to DNA than SPD. Our theoretical study with Monte Carlo simulation provides the insights into the underlying mechanism of the specific effect of NSPD on DNA.

scholarly journals Inhibitory Effects of Prunella vulgaris L. Extract on 11β-HSD1 in Human Skin Cells

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Kyung-Baeg Roh ◽  
Deokhoon Park ◽  
Eunsun Jung
Keyword(s):  
Biological Activities ◽  
Underlying Mechanism ◽  
Inhibitory Effect ◽  
Herbaceous Plant ◽  
Prunella Vulgaris ◽  
Beneficial Effects ◽  
Skin Cells ◽  
Promising Therapeutic Target ◽  
And Function

Glucocorticoids are a risk factor for age-induced skin structure and function defects, and the glucocorticoid-activating enzyme, 11β-hydroxysteroid dehydrogenase 1 (11β-HSD1), represents a promising therapeutic target. Prunella vulgaris L. (PV) is a perennial and an edible herbaceous plant normally cultivated in Asia and Europe. A recent study demonstrated a broad range of biological activities of PV including immune modulatory, antiviral, antiallergic, anti-inflammatory, antioxidant, and antidiabetic. However, little is known about the inhibitory effect of PV on 11β-HSD1. In this study, we investigated the inhibitory effect of Prunella vulgaris L. extract (PVE) and the underlying mechanism of 11β-HSD11 inhibition. Consistent with these results, cortisol levels were also reduced by PVE in vitro. The cortisone-induced translocation of glucocorticoids receptor (GR) was also attenuated. In addition, PVE inhibited a cortisone-mediated decrease in collagen content in skin. Collectively, these results suggest the beneficial effects of PVE in maintaining skin integrity.

scholarly journals Phyto-oestrogens: A potential role in the prevention of CHD?

1999 ◽  
Vol 58 (1) ◽  
pp. 193-199 ◽  
Author(s):  
Aedin Cassidy ◽  
Bruce Griffin
Keyword(s):  
Vascular Function ◽  
Premenopausal Women ◽  
Fat Distribution ◽  
Underlying Mechanism ◽  
Considerable Proportion ◽  
Chd Risk ◽  
Vessel Structure ◽  
And Function

CHD is a major cause of morbidity and mortality in women. The incidence of CHD in premenopausal women is low but increases substantially after the menopause, and this difference suggests that endogenous oestrogens are cardioprotective. Observational prospective studies have consistently shown that exogenous oestrogens also lower CHD risk. The biological mechanisms by which endogenous and exogenous oestrogens exert their protective effect are multifactorial, affecting lipids, carbohydrate metabolism, body fat distribution and blood pressure. The prevention of CHD with oestrogen therapy is therefore aimed both at correction of the traditional risk factors and at direct control of vessel structure and function. The wide international variation in rates of CHD together with the lower mortality in sub-groups of the population suggests that a considerable proportion of CHD may be prevented by dietary modification. Since phyto-oestrogens are structually similar to oestrogen, they have the potential to mimic its effects in vivo. The hypocholesterolaemic effects of soyabean protein (rich in phyto-oestrogen precursors) are well established, but the underlying mechanism and atherogenic potential of these changes are unknown. One isoflavone, genistein, has been shown in vitro to exert effects which may slow the development of atherosclerotic disease. However, further studies are required to determine the dose-related changes induced by phyto-oestrogens on serum lipoproteins, haemostasis and vascular function.

scholarly journals The Cardiovascular System in Space: Focus on In Vivo and In Vitro Studies

Biomedicines ◽  
2021 ◽  
Vol 10 (1) ◽  
pp. 59
Author(s):  
Ronni Baran ◽  
Shannon Marchal ◽  
Sebastian Garcia Campos ◽  
Emil Rehnberg ◽  
Kevin Tabury ◽  
...  
Keyword(s):  
Cellular Proliferation ◽  
Orthostatic Intolerance ◽  
Underlying Mechanism ◽  
Low Earth Orbit ◽  
Molecular Changes ◽  
Human Spaceflight ◽  
Altered Cell ◽  
And Function

On Earth, humans are subjected to a gravitational force that has been an important determinant in human evolution and function. During spaceflight, astronauts are subjected to several hazards including a prolonged state of microgravity that induces a myriad of physiological adaptations leading to orthostatic intolerance. This review summarises all known cardiovascular diseases related to human spaceflight and focusses on the cardiovascular changes related to human spaceflight (in vivo) as well as cellular and molecular changes (in vitro). Upon entering microgravity, cephalad fluid shift occurs and increases the stroke volume (35–46%) and cardiac output (18–41%). Despite this increase, astronauts enter a state of hypovolemia (10–15% decrease in blood volume). The absence of orthostatic pressure and a decrease in arterial pressures reduces the workload of the heart and is believed to be the underlying mechanism for the development of cardiac atrophy in space. Cellular and molecular changes include altered cell shape and endothelial dysfunction through suppressed cellular proliferation as well as increased cell apoptosis and oxidative stress. Human spaceflight is associated with several cardiovascular risk factors. Through the use of microgravity platforms, multiple physiological changes can be studied and stimulate the development of appropriate tools and countermeasures for future human spaceflight missions in low Earth orbit and beyond.

scholarly journals Biochemical and genetic analysis of Ecm14, a conserved fungal pseudopeptidase

2020 ◽  
Vol 21 (1) ◽  
Author(s):  
R. Christian McDonald ◽  
Matthew J. Schott ◽  
Temitope A. Idowu ◽  
Peter J. Lyons
Keyword(s):  
Enzyme Activity ◽  
Large Scale ◽  
Structure And Function ◽  
Activation Mechanism ◽  
Marker Genes ◽  
Synthetic Lethal ◽  
Fungal Process ◽  
And Function

Abstract Background Like most major enzyme families, the M14 family of metallocarboxypeptidases (MCPs) contains a number of pseudoenzymes predicted to lack enzyme activity and with poorly characterized molecular function. The genome of the yeast Saccharomyces cerevisiae encodes one member of the M14 MCP family, a pseudoenzyme named Ecm14 proposed to function in the extracellular matrix. In order to better understand the function of such pseudoenzymes, we studied the structure and function of Ecm14 in S. cerevisiae. Results A phylogenetic analysis of Ecm14 in fungi found it to be conserved throughout the ascomycete phylum, with a group of related pseudoenzymes found in basidiomycetes. To investigate the structure and function of this conserved protein, His6-tagged Ecm14 was overexpressed in Sf9 cells and purified. The prodomain of Ecm14 was cleaved in vivo and in vitro by endopeptidases, suggesting an activation mechanism; however, no activity was detectable using standard carboxypeptidase substrates. In order to determine the function of Ecm14 using an unbiased screen, we undertook a synthetic lethal assay. Upon screening approximately 27,000 yeast colonies, twenty-two putative synthetic lethal clones were identified. Further analysis showed many to be synthetic lethal with auxotrophic marker genes and requiring multiple mutations, suggesting that there are few, if any, single S. cerevisiae genes that present synthetic lethal interactions with ecm14Δ. Conclusions We show in this study that Ecm14, although lacking detectable enzyme activity, is a conserved carboxypeptidase-like protein that is secreted from cells and is processed to a mature form by the action of an endopeptidase. Our study and datasets from other recent large-scale screens suggest a role for Ecm14 in processes such as vesicle-mediated transport and aggregate invasion, a fungal process that has been selected against in modern laboratory strains of S. cerevisiae.

scholarly journals The therapeutic effects of FGF21 on diabetic nephropathy are realized by augmenting autophagy via AMPK/mTOR signaling pathway

2020 ◽  
Author(s):  
Rui Meng ◽  
Yu Cao ◽  
Mir Khoso ◽  
Kai Kang ◽  
Gui Ren ◽  
...  
Keyword(s):  
Diabetic Nephropathy ◽  
Protein Expression ◽  
Mesangial Cells ◽  
Underlying Mechanism ◽  
Histopathological Change ◽  
Therapeutic Effects ◽  
Renal Morphology ◽  
Mrna And Protein Expression ◽  
And Function

Abstract Accumulating evidence demonstrates that FGF21 plays a preventive role in the development of diabetic nephropathy (DN). However, little is known about the therapeutical effects of FGF21 on DN and underlying mechanism. In this study, FGF21 significantly ameliorated blood glucose, HbAlc, insulin resistance, renal function and histopathological change in DN mice (BKS-Leprem2Cd479/Gpt), which develop abnormalities in renal morphology and function. Our results showed that administration of FGF21 upregulated the autophagy related genes LC3Ⅱ and BCL-1 mRNA and protein expression levels. D-glucose was used for high glucose (HG) model in mesangial cells. The results showed that treatment with FGF21 reduced the levels of ROS, AGEs and inflammatory cytokines and significantly downregulated the protein expression of PCNA. Meanwhile, FGF21 significantly enhanced the expression of LC3Ⅱ and BCL-1. Besides, Our studies showed that administration of FGF21 significantly upregulated the phosphorylation of AMPK and downregulated phosphorylation of mTOR. Meanwhile, the effects of FGF21 on autophagy were reversed by siRNA against β-klotho. In conclusion, The therapeutic effects of FGF21 on diabetic nephropathy are realized and FGF21 ameliorates mesangial cell glucotoxicity and abnormal proliferation in vitro by augmenting autophagy via AMPK/mTOR pathway. These results suggest that FGF21 can be a therapeutic target against DN.

Sp1 and Sp3 transcription factors synergistically regulate HGF receptor gene expression in kidney

2003 ◽  
Vol 284 (1) ◽  
pp. F82-F94 ◽  
Author(s):  
Xianghong Zhang ◽  
Yingjian Li ◽  
Chunsun Dai ◽  
Junwei Yang ◽  
Peter Mundel ◽  
...  
Keyword(s):  
Transcription Factors ◽  
Receptor Gene ◽  
Constitutive Expression ◽  
Underlying Mechanism ◽  
Target Cells ◽  
Physical Interaction ◽  
Kidney Cells ◽  
Akt Phosphorylation ◽  
And Function

We investigated the expression pattern and underlying mechanism that controls hepatocyte growth factor (HGF) receptor (c-met) expression in normal kidney and a variety of kidney cells. Immunohistochemical staining showed widespread expression of c-met in mouse kidney, a pattern closely correlated with renal expression of Sp1 and Sp3 transcription factors. In vitro, all types of kidney cells tested expressed different levels of c-met, which was tightly proportional to the cellular abundances of Sp1 and Sp3. Both Sp1 and Sp3 bound to the multiple GC boxes in the promoter region of the c-met gene. Coimmunoprecipitation suggested a physical interaction between Sp1 and Sp3. Functionally, Sp1 markedly stimulated c-met promoter activity. Although Sp3 only weakly activated the c-met promoter, its combination with Sp1 synergistically stimulated c-met transcription. Conversely, deprivation of Sp proteins by transfection of decoy Sp1 oligonucleotide or blockade of Sp1 binding with mithramycin A inhibited c-met expression. The c-met receptor in all types of kidney cells was functional and induced protein kinase B/Akt phosphorylation in a distinctly dynamic pattern after HGF stimulation. These results indicate that members of the Sp family of transcription factors play an important role in regulating constitutive expression of the c-met gene in all types of renal cells. Our findings suggest that HGF may have a broader spectrum of target cells and possess wider implications in kidney structure and function than originally thought.

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