Microalgal and activated sludge processing for biodegradation of textile dyes.

The textile industry contributes substantially to water pollution. To investigate bioremediation of dye-containing wastewater, the decolorization and biotransformation of three textile azo dyes, Red HE8B, Reactive Green 27, and Acid Blue 29, were considered using an integrated remediation approach involving the microalga Chlamydomonas mexicana and activated sludge (ACS). At a 5 mg L-1 dye concentration, using C. mexicana and ACS alone, decolorization percentages of 39%-64% and 52%-54%, respectively, were obtained. In comparison, decolorization percentages of 75%-79% were obtained using a consortium of C. mexicana and ACS. The same trend was observed for the decolorization of dyes at higher concentrations, but the potential for decolorization was low. The toxic azo dyes adversely affect the growth of microalgae and at high concentration 50 mg L-1 the growth rate inhibited to 50-60% as compared to the control. The natural textile wastewater was also treated with the same pattern and got promising results of decolorization (90%). Moreover, the removal of BOD (82%), COD (72%), TN (64%), and TP (63%) was observed with the consortium. The HPLC and GC-MS confirm dye biotransformation, revealing the emergence of new peaks and the generation of multiple metabolites with more superficial structures, such as N-hydroxy-aniline, naphthalene-1-ol, and sodium hydroxy naphthalene. This analysis demonstrates the potential of the C. mexicana and ACS consortium for efficient, eco-friendly bioremediation of textile azo dyes.

Molecular characterization of azoreductase and its potential for the decolorization of Remazol Red R and Acid Blue 29.

Azoreductase is a reductive enzyme that efficiently biotransformed textile azo dyes. This study demonstrated the heterologous overexpression of the azoreductase gene in Escherichia coli for the effective degradation of Remazol Red-R and Acid-Blue 29 dyes. The AzK gene of Klebsiella pneumoniae encoding a ≈22 kDa azoreductase enzyme was cloned into the pET21+C expression vector. The inoculum size of 1.5%, IPTG concentration of 0.5 mM, and incubation time of 6 h were optimized by response surface methodology a statistical tool. The crude extract showed 76% and 74%, while the purified enzyme achieved 94% and 93% decolorization of RRR and AB-29, respectively in 0.3 h. The reaction kinetics showed that RRR had a Km and Vmax value of 0.058 mM and 1416 U mg-1, respectively at an NADH concentration of 10 mM. HPLC and GC-MS analyses showed that RRR was effectively bio-transformed by azoreductase to 2-[3-(hydroxy-amino) benzene-1-sulfonyl and AB-29 to aniline and 3-nitrosoaniline. This study explored the potential of recombinant azoreductase isolated from K. pneumoniae in the degradation of toxic textile azo dyes into less toxic metabolites.

Dose and duration-dependent toxicological evaluation of lead acetate in chicks.

Lead is one of the utmost contaminated and dangerous heavy metals. This toxicant ultimately enters into the human body through the food chain and accumulated in the body because the animal/human body has not an appropriate mechanism to excrete it from the body. The main objective of the present research was to assess the toxicological effects of lead on body weights, biochemical, and hematological parameters of chickens and also to measure its bioaccumulation in the brain. Lead acetate was administrated orally at doses of 0, 71, 142, 213, and 284 mg/kg of body weight of chicken for groups A, B, C, D, and E, respectively. Along with determination of biometry of all experimental chicks, hematological [hemoglobin (Hb), packed cell volume (PCV), mean corpuscular hemoglobin concentration (MCHC), total erythrocyte count (TEC), white blood cells (WBCs), leukocyte differential count (LDC)] and biochemical [low density lipoprotein (LDL), total protein, high-density lipoprotein (HDL), and alanine aminotransferase (ALT)] parameters were measured. The present study showed that the bodyweight of chickens was not affected significantly by lead acetate exposure. The levels of MCHC, PCV, TEC, Hb, LDL, HDL, and total protein were found to be significantly decreased while WBC, LDC, and ALT profile were enhanced due to administration of lead acetate. Bioaccumulation of lead acetate was found to be higher in the brain. We conclude that the chronic administration of lead acetate affected the blood and biochemical profile of exposed chicken. These effects might be due to the accumulation of the chemical in certain vital organ(s). However, further studies in the future are suggested to refine such findings.

Effect of Honey (Apis dorsata [Hymenoptera: Apidae]) on Larval Growth and Silk Cocoon Yield of Bombyx mori (Lepidoptera: Bombycidae).

The present study was carried out to determine the influence of 2% aqueous honey (Apis dorsata Fabricius, 1793 [Hymenoptera: Apidae]) on larval growth and silk cocoon yield of fifth-instar larvae of the silkworm, Bombyx mori (Linnaeus, 1758) (Lepidoptera: Bombycidae). The larvae of silkworms (Chinese HUAKAND2) were divided into a control and an experimental groups (n = 20 in each group). Control group was fed with plain mulberry leaves throughout the fifth instar, whereas the experimental group was offered mulberry leaves dipped in 2% aqueous solution of honey every other day for 4 d (days 1, 3, 5, and 7). On the other days (days 2, 4, 6, and 8), plain mulberry leaves were offered to larvae. Results showed that the average weight gain in larvae of the experimental group was 348.23 and 204.54% in case of the control group. Uneaten mulberry leaves were weighed; the control group left 34.05% of their leaves and the treated group 28.54%. The cocoon formation in the honey-treated larvae was more uniform in shape than the control group. Furthermore, honey-treated larvae began to form cocoons 7.8 ± 0.23 h earlier than the control group. We also recorded an increase of 15.34% in average weight of cocoons of the experimental group when compared with the control. Average shell percentage of fresh silk cocoons of the control and experimental groups was 20.5 and 23.5%, respectively. It is concluded from the study that 2% aqueous honey has positive impact on the larval growth and cocoon yield of B. mori.

Effect of Milking Method, Diet, and Temperature on Venom Production in Scorpions.

In the present study, two common buthid scorpions, i.e., Androctonus finitimus (Pocock, 1897) (Scorpiones: Buthidae) and Hottentota tamulus (Fabricus, 1798) (Scorpiones: Buthidae), were maintained in the laboratory for venom recovery. The aim of study was to compare the quantity and quality of venom extracted from scorpions by manual and electrical method. We also recorded the effect of diet and temperature on venom production. Results of our study revealed that electrical method yielded good quality and higher quantity of venom as compared to manual method. The quantity of venom by two studied species differed statistically. We recorded the effect of food on venom production by providing different prey items to the scorpions and found that grasshopper nymphs and adults were the best diet for the scorpions to get maximum yield of venom as compared to other prey types (house crickets, house flies, and moths). Production of venom and activity of scorpions was found to be associated with temperature. During winter season, venom recovery was comparatively low as compared to the hottest part of year; when venom milking and activity of scorpions both were increased.

Molecular Characterization of a Copper Metallothionein Gene From a Ciliate Tetrahymena farahensis.

A new copper metallothionein (TfCuMT) gene has been identified from a locally isolated ciliate Tetrahymena farahensis. It contains 327 nucleotides encoding a peptide chain of 108 amino acids and belongs to class MTT2 and subfamily 7b. Amplification from both gDNA and mRNA confirmed the intronless nature of this gene. Like most of the metallohtioneins, cysteine residues contribute nearly 30% content with the specific CKC motifs. Structural repeats present in peptide sequence of TfCuMT indicate internal duplication of gene at some stage of gene evolution. The predicted model of copper metallothionein protein showed that copper ions are mainly chelated by thiol sulfur of cysteine residues and are embedded in the folds of polypeptide chain. For in vivo expression of TfCuMT in Escherichia coli host cells the classical stop codons, which coded for glutamine in the ciliate were mutated to CAA and CAG through site directed mutagenesis. The mutated gene showed higher expression in pET28a expression vector compared with pET21a. Optimum expression was obtained after 6-8 h of 0.1 mM IPTG induction. Stability of His tagged TfCuMT in 5% SDS was low, with half-life of about 104 min. Presence of 1.0 µM copper increased the expression level by 1.65-fold. Presence of 100 µM Cysteine in culture medium caused 2.4-fold increase in expression level. His tagged TfCuMT was purified through affinity chromatography using NTN-His binding resin in the presence of 0.1 M imidazole and NaCl. The modeled structure of the TfCuMT showed a cleft for Cu binding with correct orientation of Cys residues in the motif CKC. J. Cell. Biochem. 117: 1843-1854, 2016. © 2016 Wiley Periodicals, Inc.