RESUMO
Lichen is a symbiotic organism that exists as a single composite body consisting of a mycobiont (fungus) and a photobiont (algae or a cyanobacterium). Many lichen species are considered as extremophiles due to their tolerance to radiation, desiccation, temperature and pollution. However, not all lichen species are tolerant to harsh environmental conditions as several species are sensitive for example to nitrogen, sulphur, acidity, heavy metals, halogens (e.g. fluoride) and ozone. Thus, to better understand why some lichens can withstand exposure to pollutants as opposed to those that are susceptible, we focused on the lichen species of Dirinaria known for their wide distribution in the tropics, subtropics and pantropical, and moderate tolerance to air pollution. Their moderate tolerance to air pollution affords them to thrive in good air quality environments as well as polluted air environments. Lichen samples of Dirinaria sp., UKM-J1 and UKM-K1, were respectively collected from two areas with different levels of air quality based on Air Pollutant Index or API (with index pollutant criteria of PM10, carbon monoxide, ozone, nitrogen dioxide and sulfur dioxide) in the outskirt of Jerantut (UKM-J1), a rural area in the middle of Peninsular Malaysia and the township of Klang (UKM-K1), in a busy area of the Klang Valley, Malaysia. API was monitored throughout 2012-2013 whereby the sample collection site in Klang showed markedly higher concentrations of pollutants in all the index pollutant criteria as compared to that of Jerantut. We performed transcriptome sequencing using Illumina RNA-seq technology and de novo assembly of the transcripts from the lichen samples. Raw reads from both libraries were deposited in the NCBI database with the accession number SRP138994.
RESUMO
BACKGROUND AIMS: Suspension mononuclear cells (MNCs) can be differentiated into osteoblasts with the induction of ascorbic acid and ß-glycerophosphate. The aim of this study was to determine the ability of suspension MNCs to differentiate into osteoblasts using ascorbic acid only. METHODS: Suspension MNCs were obtained by a combination of gradient centrifugation and culture selection. Suspension MNCs were subjected to differentiation assay by culturing them inside proliferation medium supplemented with 10 µg/mL, 30 µg/mL, 50 µg/mL, 60 µg/mL, 90 µg/mL and 500 µg/mL of ascorbic acid. Proliferation medium supplemented with 50 µg/mL ascorbic acid and 10 mmol/L ß-glycerophosphate was used as a positive control for osteoblast induction, and proliferation medium without ascorbic acid was used as a negative control. Differentiation analysis was performed using alkaline phosphatase (ALP) assay, von Kossa staining and expression of osteoblast-related genes. RESULTS: With all concentrations of ascorbic acid used, there was a significant increase (P < 0.05) in ALP-specific activity and mineralized nodule formation throughout the differentiation course compared with negative control. Ascorbic acid was also able to activate the expression of osteopontin (SPP1), osteonectin (SPARC) and runt-related transcription factor 2 (RUNX2) messenger RNA in positive control and ascorbic acid-induced MNCs (30 µg/mL and 90 µg/mL) but not in negative control. CONCLUSIONS: Ascorbic acid alone was sufficient to induce osteoblast differentiation from suspension MNCs; 30-90 µg/mL of ascorbic acid was found to be the optimal concentration. Ascorbic acid can be used as a nutritional supplement for cellular therapy of bone-related disease.
