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Haematococcus lacustris (Girod-Chantrans) Rostafinski (Chlorophyta) is the richest microalgal source of astaxanthin. Natural astaxanthin from H. lacustris has been widely studied and used for commercial production worldwide. In this study, we examined the effects of 11 antibiotics (dihydrostreptomycin sulphate, neomycin, chloramphenicol, penicillin, streptomycin, ampicillin, kanamycin, gentamycin, hygromycin B, tetracycline, and paromomycin) on the biomass dry weight, growth, and astaxanthin yield of H. lacustris using Jaworski's medium without a nitrogen source. Astaxanthin content in H. lacustris was improved in the presence of ampicillin (0.25 g/L, 0.5 g/L, 1 g/L), chloramphenicol (0.25 g/L), and penicillin (0.25 g/L, 0.5 g/L, 1 g/L) in comparison to the control on day 15. The greatest increase in astaxanthin content on day 15 (6.69-fold) was obtained with the addition of penicillin (0.5 g/L) in comparison to the control. Similarly, on day 15, the cell numbers were also the highest for the H. lacustris culture grown with the addition of penicillin (0.5 g/L). [ABSTRACT FROM AUTHOR]

Selective herbicides are used to control undesirable vegetation or weeds in fields without harming crops. Herbicide use for weed management can directly impact the densities of insect pests in agricultural communities as a result of insect mortality during and immediately after application. In insects, the glutathione S‐transferase (GST) enzyme is involved in both the detoxification process and the defense of cellular membranes against oxidative damage. In this study, two TmGSTs (TmGST‐iso1 and TmGST‐iso2) were identified and characterized to elucidate the GST family in Tenebrio molitor. Among the developmental stages of T. molitor, eggs had the highest expression levels of TmGST‐iso1. TmGST‐iso2 expression was highest in the pre‐pupal stage. TmGST‐iso1 expression was high in the guts of early and late larvae, whereas TmGST‐iso2 expression was not observed in early larvae. Adults, both male and female, had the highest levels of TmGST‐iso1 mRNA expression in the gut and reproductive organs, and the highest levels of TmGST‐iso2 expression in the reproductive organs. Quantitative polymerase chain reaction was used to investigate the impact of treatment with butachlor on the mRNA expression of TmGST‐iso1 and TmGST‐iso2 in larvae. TmGST‐iso1 expression increased in the butachlor‐treated group after 3 and 24 h, whereas TmGST‐iso2 expression peaked at 24 h after treatment. This study provides vital information about the detoxifying activities of T. molitor. [ABSTRACT FROM AUTHOR]