-Uncontrolled exposure of active and passive smokers to trace metals causes increase in health risks. The primary objective of this study was to determine whether local and imported cigarette brands used in Pakistan, have elevated levels of metals or not. Six metals manganese (Mn), cobalt (Co), copper (Cu), cadmium (Cd), lead (Pb) and zinc (Zn) were determined in tobacco of twenty cigarette contamination chances and for complete digestion of analytes a microwave digester was used. The analytical results showed highest concentration of Mn (84.78 μg/g dry weight), Cd (0.525 μg/g dry weight) and Zn (14.34 μg/g dry weight) metals in imported brands in relation to counterparts from the local brands. Certain elevated levels were observed for Co (3.344 μg/g dry weight), Pb (14.16 μg/g dry weight) and Cu (7.889 μg/g dry weight) metals in local brands. The inter-metal relationships in the tobacco of local and imported cigarette brands showed some integrated variation in the selected metal levels. In view of health risk associated with the above metals, there should be a strict quality control over monitoring of heavy metals during growing, processing and smoking of tobacco. Therefore, it is prudent to minimize exposure to toxic substances whenever possible because smoking and exposure to cigarette smoke is a confounder to be taken into account when carrying out epidemiological studies on human exposure to metals.

Background WRKY transcription factors (TFs) have been suggested to play crucial roles in the response to biotic and abiotic stresses. This study is the first to report the alkaline salt regulation of the WRKY gene. Results In this study, we cloned a WRKY gene (SlWRKY28) from the Salix linearistipularis and then transferred to the Populus davidiana × P. bolleana for expression. Sequence analysis on the transcriptome of Salix linearistipular showed the significant up-regulation of WRKY gene expression in response to salt-alkali stress in seedlings. Our data showed that SlWRKY28 localized to the nucleus. Furthermore, the expression of the SlWRKY28 from female plants increased with saline-alkali stress according to the northern blot analysis results. The results of 3,3′-Diaminobenzidine (DAB) staining showed that hydrogen peroxide (H2O2) concentration was lower under stress, but ascorbate peroxidase (APX) enzyme activity was significantly higher in the overexpressed plants than that in non-transgenic (NT) plants. Conclusions We found out the SlWRKY28 induced regulation of the enzyme gene in the reactive oxygen species (ROS) scavenging pathway is a potential mechanism for transgenic lines to improve their resistance to alkaline salt. This study shows theoretical and practical significance in determining SlWRKY28 transcription factors involved in the regulation of alkaline salt tolerance.

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High biodegradability of starch is a major limitation for its commercial usage in developing urea‐crosslinked starch (UcS) film as slow‐release fertilizer. For solving this problem, UcS films were reinforced with 5–20% kraft lignin. Implication of lignin as a macromolecule was tested for slowing the biodegradability of UcS films. These films were biodegraded and characterized in an aerobic soil burial test up to the 60th day. The results were drawn for biodegraded lignin‐reinforced films through comparison made with biodegraded control film, which received 0% lignin. The Fourier transform infrared spectroscopy peaks at 1625 and 1665 cm−1 corresponded to UcS and were found to be more conspicuous in biodegraded lignin‐reinforced films. Thermogravimetric analysis of biodegraded lignin‐reinforced films showed higher thermal stability. This was inferred from the decrease of ∼85.45°C in the thermal decomposition temperature at 5% weight loss (onset temperature), the increase of ∼31.69°C in the thermal decomposition temperature at maximum weight loss, and the increase of ∼12.90% in char. The molecular weight distribution of the biodegraded lignin‐reinforced films reduced not more than ∼1% and the polydispersity index was conserved to 1.4. Light microscopy of the biodegraded lignin—reinforced films reduced not more than ∼1% and polydispersity index was conserved to 1.4. Light microscopy of biodegraded lignin‐reinforced films showed the shape of starch particles was oblong, less disrupted, and wrinkled. Field‐emission electron microscopy showed lignin addition favored more the fungal growth beside formation of cavities. Atomic force microscopy showed the average surface roughness increased 2.00–7.32 times more as a result of residual lignin's accumulation in biodegraded lignin‐reinforced films. Based on the understanding of biodegradability in UcS films, a theoretical framework has also been proposed for biodegradability‐driven urea‐nitrogen release in soil.

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