RESUMO
Malvaceae family, also known as the Mallow family, is a family of flowering plants containing Hibiscus rosa-sinensis and other plants of high medicinal value. This study focuses on the challenges associated with high-quality RNA extraction from Hibiscus rosa-sinensis and its related plants characterized by high levels of mucilage and phenolic compounds in their tissues. High mucilage and secondary metabolite content pose obstacles in obtaining high-quality RNA, negatively impacting downstream applications, such as gene expression analysis. Our research aimed to develop an efficient RNA extraction method tailored to the unique characteristics of Malvaceae family plants especially Hibiscus rosa-sinensis. Through the substitution of NaCl with KCl, a crucial component of the CTAB buffer, our methodology successfully addressed the challenges posed by high mucilage and phenolic compound levels. This modification led to a significant reduction in sample viscosity, which is because of the high mucilage in these plants. Our modified CTAB extraction method yielded significantly more RNA with higher purity than the conventional CTAB methods alone. The extracted RNA was largely intact, as indicated by 28S/18S ratios and RIN values, yielding high-quality RNA with improved purity suggested by the 260/280 and 260/230 ratios. The proposed approach not only serves as a solution to the specific challenges encountered in Hibiscus rosa-sinensis but also holds promise for broader applications across different plants within the family.
RESUMO
Considering the significance of PM1 aerosol in assessing health impacts of air pollution, an extensive analysis of PM1 samples collected at an urban site in Delhi is presented in this study. Overall, PM1 contributed to about 50 % of PM2.5 mass which is alarming especially in Delhi where particle mass loadings are usually higher than prescribed limits. Major portion of PM1 consisted of organic matter (OM) that formed nearly 47 % of PM1 mass. Elemental carbon (EC) contributed to about 13 % of PM1 mass, whereas SO42- (16 %), NH4+ (10 %), NO3- (4 %) and Cl- (3 %) were the major inorganic ions present. Sampling was performed in two distinctive campaign periods (in terms of meteorological conditions and heating (fire) activities), during the year 2019, each spanning two-week time, i.e. (i) September 3rd-16th (clean days), and (ii) November 22nd-December 5th (polluted days). Additionally, PM2.5 and black carbon (BC) were measured simultaneously for subsequent analysis. The 24-h averaged mean concentrations of PM2.5 and BC during clean days (polluted days) were 70.6 ± 26.9 and 3.9 ± 1.0 µg m-3 (196 ± 104 and 7.6 ± 4.1 µg m-3), respectively, which were systematically lower (higher) than that of the annual mean (taken from studies conducted at same site in 2019) of 142 and 5.7 µg m-3, respectively. Changes in characteristic ratios (i.e., organic carbon (OC)/elemental carbon (EC) and K+/EC) of chemical species detected in PM1 show an increase in biomass emissions during polluted days. Increase in biomass emission can be attributed to increase in heating practices (burning of biofuels such as wood logs, straw, and cow-dung cake) in- and around- Delhi because of fall in temperature during second campaign. Furthermore, a significant increase in NO3- fraction of PM1 is observed during second campaign which shows fog processing of NOX due to conducive meteorological conditions in winters. Also, comparatively stronger correlation of NO3- with K+ during second campaign (r = 0.98 as compared to r = 0.5 during first campaign) suggests the increased heating practices to be a contributing factor for increased fraction of NO3- in PM1. We observed that during polluted days, meteorological parameters such as dispersion rate also played a major role in intensifying the impact of increased local emissions due to heating activities. Apart from this, change in the direction of regional emission transport to study site and the topology of Delhi are the possible reasons for the elevated pollution level, especially PM1 during winter in Delhi. This study also suggests that black carbon measurement techniques used in current study (optical absorbance with heated inlet and evolved carbon techniques) can be used as reference techniques to determine the site-specific calibration constant of optical photometers for urban aerosol.