43 research outputs found

    Kondisi Optimum Fusi Protoplas Antara Jamur Tiram Putih {Peurotus Floridae) Dan Jamur Tiram Coklat {Pleurotus Cystidiosusy[optimizing Conditions for Protoplast Fusion Between White Oyster Mushroom {Pleurotus Floridae) and Brown Oyster Mushroom {Pleurotus Cystidiosus)]

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    Genetic crossing of white oyster mushroom to introduce longer storage life trait can only be done within individuals in this particular species. However, longer storage life trait is possessed by brown oyster mushroom (Pleurotus cystidiosus) which is other species within this genus. Thefeore, protoplast fusion between white oyster mushroom (Peurotus floridae) and brown oyster mushroom (Pleurotus cystidiosus) was conducted to hopefully obtain an oyster mushroom strain that has higher production and longer storage life. Protoplast fusion was done by isolating protoplast from 5-days old monokaryotic mycelia grown in PDB. As much as 3.15 x 10 protoplasts/ml were harvested using mixture of cellulase Onozuka R-10 (1%) and macerozyme R-10 (1%) from brown oyster mushroom with 80.61% viability. Similarly, 3.71 x 10 protoplasts/ml were harvested using lysing enzyme (2%)from brown oyster mushroom with 83.68% viability. Protoplast fusion were conducted using 0% (control), 30%, 40% and 50% of PEG6000. Fusion periods were done at 10, 20 and 30 minutes. The candidate fusants were then screened using MRM (minimum regeneration media) media. Based on this experiment, the optimum conditions for protoplast fusion is 10 minutes incubation using 40% PEG6000 that yielded 121 colonies grown on MRM media as candidate fusants

    AVP neurons in the paraventricular nucleus of the hypothalamus regulate feeding.

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    Melanocortins and their receptors are critical components of energy homeostasis and the paraventricular nucleus of the hypothalamus (PVH) is an important site of melanocortin action. Although best known for its role in osmoregulation, arginine vasopressin (AVP) has been implicated in feeding and is robustly expressed in the PVH. Since the anorectic melanocortin agonist MTII activates PVH-AVP neurons, we hypothesized that PVH-AVP neurons contribute to PVH-mediated anorexia. To test this, we used an AVP-specific Cre-driver mouse in combination with viral vectors to acutely manipulate PVH-AVP neuron function. Using designer receptors exclusively activated by designer drugs (DREADDs) to control PVH-AVP neuron activity, we show that activation of PVH-AVP neurons acutely inhibits food intake, whereas their inhibition partially reverses melanocortin-induced anorexia. We further show that MTII fails to fully suppress feeding in mice with virally-induced PVH-AVP neuron ablation. Thus PVH-AVP neurons contribute to feeding behaviors, including the acute anorectic response to MTII

    KLRG1+ natural killer cells exert a novel antifibrotic function in chronic hepatitis B

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    Background & Aims: Natural killer (NK)cells are known to exert strong antiviral activity. Killer cell lectin-like receptor subfamily G member 1 (KLRG1)is expressed by terminally differentiated NK cells and KLRG1-expressing lymphocytes are known to expand following chronic viral infections. We aimed to elucidate the previously unknown role of KLRG1 in the pathogenesis of chronic hepatitis B (CHB). Methods: KLRG1+ NK cells were taken from the blood and liver of healthy individuals and patients with CHB. The phenotype and function of these cells was assessed using flow cytometry and in vitro stimulation. Results: Patients with CHB had a higher frequency of KLRG1+ NK cells compared to healthy controls (blood 13.4 vs. 2.3%, p <0.0001 and liver 23.4 vs. 2.6%, p <0.01). KLRG1+ NK cells were less responsive to K562 and cytokine stimulation, but demonstrated enhanced cytotoxicity (9.0 vs. 4.8%, p <0.05)and IFN-γ release (8.0 vs. 1.5%, p <0.05)via antibody dependent cellular cytotoxicity compared to their KLRG1− counterparts. KLRG1+ NK cells possessed a mature phenotype, demonstrating stronger cytolytic activity and IFN-γ secretion against hepatic stellate cells (HSCs)than KLRG1− NK cells. Moreover, KLRG1+ NK cells more effectively induced primary HSC apoptosis in a TRAIL-dependent manner. Increased KLRG1+ NK cell frequency in the liver and blood was associated with lower fibrosis stage (F0/F1)in patients with CHB. Finally, the expression of CD44, degranulation and IFN-γ production were all increased in KLRG1+ NK cells following stimulation with osteopontin, the CD44 ligand, suggesting that HSC-derived osteopontin may cause KLRG1+ NK cell activation. Conclusions: KLRG1+ NK cells likely play an antifibrotic role during the natural course of CHB infection. Harnessing this antifibrotic function may provide a novel therapeutic approach to treat liver fibrosis in patients with CHB. Lay summary: Individuals that are chronically infected with hepatitis B virus (HBV)possess an increased number of immune cells, called natural killer (NK)cells expressing the surface marker KLRG1 in the blood and liver. Here, we demonstrate that these specific NK cells are able to kill activated stellate cells in the liver. Because activated stellate cells contribute to liver scarring, i.e. fibrosis, and subsequent liver dysfunction in individuals with chronic HBV infection, KLRG1+ NK cells are a novel immune cell type that can limit liver scarring
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