25 research outputs found

    Isolation and Identification of Endophytic Fungi from Actinidia macrosperma and Investigation of Their Bioactivities

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    Endophytic fungi from the Chinese medicinal plant Actinidia macrosperma were isolated and identified for the first time. This was the first study to evaluate their cytotoxic and antitumour activities against brine shrimp and five types of tumour cells, respectively. In total, 17 fungal isolates were obtained. Five different taxa were represented by 11 isolates, and six isolates were grouped into the species of Ascomycete Incertae sedis with limited morphological and molecular data. Cytotoxic activity has been found in most isolates except AM05, AM06, and AM10. The isolates AM07 (4.86 μg/mL), AM11 (7.71 μg/mL), and AM17 (14.88 μg/mL) exhibited significant toxicity against brine shrimp. The results of the MTT assay to assess antitumour activity revealed that 82.4% of isolate fermentation broths displayed growth inhibition (50% inhibitory concentration IC50< 100 μg/mL). Moreover, AM07, AM11, and AM17 showed strong antitumour activity in all the cell lines examined. These results suggest that endophytic fungi in A. macrosperma are valuable for the isolation and identification of novel cytotoxic and antitumour bioactive agents

    SEIPIN Regulates Lipid Droplet Expansion and Adipocyte Development by Modulating the Activity of Glycerol-3-phosphate Acyltransferase

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    Berardinelli-Seip congenital lipodystrophy 2 (BSCL2) is caused by loss-of-function mutations in SEIPIN, a protein implicated in both adipogenesis and lipid droplet expansion but whose molecular function remains obscure. Here, we identify physical and functional interactions between SEIPIN and microsomal isoforms of glycerol-3-phosphate acyltransferase (GPAT) in multiple organisms. Compared to controls, GPAT activity was elevated in SEIPIN-deficient cells and tissues and GPAT kinetic values were altered. Increased GPAT activity appears to underpin the block in adipogenesis and abnormal lipid droplet morphology associated with SEIPIN loss. Overexpression of Gpat3 blocked adipogenesis, and Gpat3 knockdown in SEIPIN-deficient preadipocytes partially restored differentiation. GPAT overexpression in yeast, preadipocytes, and fly salivary glands also formed supersized lipid droplets. Finally, pharmacological inhibition of GPAT in Seipin-/- mouse preadipocytes partially restored adipogenesis. These data identify SEIPIN as an evolutionarily conserved regulator of microsomal GPAT and suggest that GPAT inhibitors might be useful for the treatment of human BSCL2 patients

    Development of a Mode-Locked Fiber Laser Utilizing a Niobium Diselenide Saturable Absorber

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    The saturable absorber of niobium diselenide (NbSe2), with a wide working bandwidth and excellent nonlinear optical response, was prepared using liquid-phase exfoliation. Its saturation intensity and modulation depth were 5.35 MW/cm2 and 6.3%, respectively. Stable mode-locking with a center wavelength of 1558.7 nm of an erbium-doped fiber laser based on a NbSe2 saturable absorber was successfully achieved. The maximum average output power of the mode-locked laser was 6.93 mW, with a pulse width of 1.3 ps and a repetition rate of 25.31 MHz at a pump power of 550 mW. The results show that NbSe2 is a promising photoelectric modulation material owing to its excellent nonlinear optical properties

    Protein kinase C and protein kinase A are involved in the protection of recombinant human glucagon‐like peptide‐1 on glomeruli and tubules in diabetic rats

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    Abstract Aims/Introduction Blockade or reversal the progression of diabetic nephropathy is a clinical challenge. The aim of the present study was to examine whether recombinant human glucagon‐like peptide‐1 (rhGLP‐1) has an effect on alleviating urinary protein and urinary albumin levels in diabetic rats. Materials and Methods Streptozotocin‐induced diabetes rats were treated with rhGLP‐1 insulin and saline. Using immunostaining, hematoxylin–eosin, electron microscopy and periodic acid–Schiff staining to study the pathology of diabetic nephropathy, and we carried out quantitative reverse transcription polymerase chain reaction, western blot and immunohistochemistry to identify the differentially expressed proteins. The mechanism was studied through advanced glycation end‐products‐induced tubular epithelial cells. Results rhGLP‐1 inhibits protein kinase C (PKC)‐β, but increases protein kinase A (PKA), which reduces oxidative stress in glomeruli and in cultured glomerular microvascular endothelial cells. In tubules, rhGLP‐1 increased the expression of two key proteins related to re‐absorption – megalin and cubilin – which was accompanied by downregulation of PKC‐β and upregulation of PKA. On human proximal tubular epithelial cells, rhGLP‐1 enhanced the absorption of albumin, and this was blocked by a PKC activator or PKA inhibitor. Conclusions These findings suggest that rhGLP‐1 can reverse diabetic nephropathy by protecting both glomeruli and tubules by inhibiting PKC and activating PKA

    Long-Term Field Biochar Application for Rice Production: Effects on Soil Nutrient Supply, Carbon Sequestration, Crop Yield and Grain Minerals

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    Research is still under-represented for the long-term impacts of field biochar application on soil fertility, rice production and mineral nutrition and soil C sequestration. To investigate these effects, a field trial was established in the fall of 2010 with low (2.4 t ha−1), intermediate (6 t ha−1) and high (12 t ha−1) biochar doses. The biochar effect on soil nutrients is more pronounced in the surface soil and is dose dependent. In the surface soil, biochar application increased the availability of soil N, P and K. High dose decreased soil total Fe by 11.6% and Mn by 20.7%, leading to a slight but insignificant decrease in grain Fe and Mn concentration. The intermediate and high doses significantly increased the soil available Zn by 96.2% and 227.9% but did not affect the grain Zn concentration. Grain Cu concentration was significantly decreased by the intermediate (−19.6%) and high (−14.3%) dose of biochar. Biochar had a slight but insignificant boost on rice yield. Soil total C and N increased linearly with biochar application for the surface soil only where biochar was applied. In conclusion, with great soil C sequestration capacity, the long-term field return of biochar is beneficial for improving the soil macronutrient and Zn fertility, but caution is needed, as higher doses of biochar could potentially lead to a decrease in soil Fe and Mn and a reduction in grain Cu concentration

    Long-Term Field Biochar Application for Rice Production: Effects on Soil Nutrient Supply, Carbon Sequestration, Crop Yield and Grain Minerals

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    Research is still under-represented for the long-term impacts of field biochar application on soil fertility, rice production and mineral nutrition and soil C sequestration. To investigate these effects, a field trial was established in the fall of 2010 with low (2.4 t ha&minus;1), intermediate (6 t ha&minus;1) and high (12 t ha&minus;1) biochar doses. The biochar effect on soil nutrients is more pronounced in the surface soil and is dose dependent. In the surface soil, biochar application increased the availability of soil N, P and K. High dose decreased soil total Fe by 11.6% and Mn by 20.7%, leading to a slight but insignificant decrease in grain Fe and Mn concentration. The intermediate and high doses significantly increased the soil available Zn by 96.2% and 227.9% but did not affect the grain Zn concentration. Grain Cu concentration was significantly decreased by the intermediate (&minus;19.6%) and high (&minus;14.3%) dose of biochar. Biochar had a slight but insignificant boost on rice yield. Soil total C and N increased linearly with biochar application for the surface soil only where biochar was applied. In conclusion, with great soil C sequestration capacity, the long-term field return of biochar is beneficial for improving the soil macronutrient and Zn fertility, but caution is needed, as higher doses of biochar could potentially lead to a decrease in soil Fe and Mn and a reduction in grain Cu concentration

    Follistatin-Like 1: A Potential Mediator of Inflammation in Obesity

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    Obesity is associated with a state of chronic low-grade inflammation, which contributes to insulin resistance and type 2 diabetes. However, the molecular mechanisms that link obesity to inflammation are not fully understood. Follistatin-like 1 (FSTL1) is a novel proinflammatory cytokine that is expressed in adipose tissue and secreted by preadipocytes/adipocytes. We aimed to test whether FSTL1 could have a role in obesity-induced inflammation and insulin resistance. It was found that FSTL1 expression was markedly decreased during differentiation of 3T3-L1 preadipocytes but reinduced by TNF-α. Furthermore, a significant increase in FSTL1 levels was observed in adipose tissue of obese ob/ob mice, as well as in serum of overweight/obese subjects. Mechanistic studies revealed that FSTL1 induced inflammatory responses in both 3T3-L1 adipocytes and RAW264.7 macrophages. The expression of proinflammatory mediators including IL-6, TNF-α, and MCP-1 was upregulated by recombinant FSTL1 in a dose-dependent manner, paralleled with activation of the IKKβ-NFκB and JNK signaling pathways in the two cell lines. Moreover, FSTL1 impaired insulin signaling in 3T3-L1 adipocytes, as revealed by attenuated phosphorylation of both Akt and IRS-1 in response to insulin stimulation. Together, our results suggest that FSTL1 is a potential mediator of inflammation and insulin resistance in obesity

    Transthyretin amyloid cardiomyopathy: The emerging role of cardiac amyloid imaging COMMENT

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    10.47102/annals-acadmedsg.202164ANNALS ACADEMY OF MEDICINE SINGAPORE507566-57
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