Supplementation of micro-nutrients to growth media of microalgae-induced biomass and fatty acids composition for clean energy generation.

The presence of harmful heavy metals (HMs) in the aquatic environment can damage the environment and threaten human health. Traditional remediation techniques can have secondary impacts. Thus, more sustainable approaches must be developed. Microalgae have biological properties (such as high photosynthetic efficiency and growth), which are of great advantage in the HMs removal. In this study, the effect of various concentrations (2×, 4×, and 6×) of copper (Cu), cobalt (Co), and zinc (Zn) on microalgae (C. sorokiniana GEEL-01, P. kessleri GEEL-02, D. asymmetricus GEEL-05) was investigated. The microalgal growth kinetics, HMs removal, total nitrogen (TN), total phosphor (TP), and fatty acids (FAs) compositions were analyzed. The highest growth of 1.474 OD680nm and 1.348 OD680nm was obtained at 2× and 4×, respectively, for P. kessleri GEEL-02. P. kessleri GEEL-02 showed high removal efficiency of Cu, Co, and Zn (38.92-55.44%), (36.27-68.38%), and (32.94-51.71%), respectively. Fatty acids (FAs) analysis showed that saturated FAs in C. sorokiniana GEEL-01 and P. kessleri GEEL-02 increased at 2× and 4× concentrations while decreasing at 6×. For P. kessleri GEEL-02, the properties of biodiesel including the degree of unsaturation (UD) and cetane value (CN) increased at 2×, 4×, and 6× as compared to the control. Thus, this study demonstrated that the three microalgae (particularly P. kessleri GEEL-02) are more suitable for nutrient and HMs removal coupled with biomass/biodiesel production.

In-vitro cytotoxicity of nickel oxide nanoparticles against L-6 cell-lines: MMP, MTT and ROS studies.

In the present work we synthesize nickel oxide nanoparticles (NiO NPs) using Rhododendron arboretum (flower) (RNi), Tinospora cordifolia (stems) (GNi), Corylus jacquemontii (seeds) (CNi), and Nardostachys jatamansi (roots) (NNi) extracts by co-precipitation method. The synthesized NiO NPs were characterized in detail in terms of their morphological, crystalline nature, structural and antiproliferative activity against rat skeletal myoblast (L-6) cell lines. Morphological studies confirmed the formation of nanoparticles, while the structural and compositional characterization revealed the well-crystallinity and high purity of the synthesized nanoparticles. For biological applications and cytotoxicity examinations of the synthesized NPs, the rat skeletal myoblast (L-6) cell lines were subjected to study. By detailed cytotoxic investigations, it was observed that among the four kinds of NiO NPs prepared through different plant extracts, the Tinospora cordifolia (stems) showed strong antiproliferative activity against rat skeletal myoblast (L-6) cell lines and the calculated IC50 was 1.671 mg/mL. The observed antiproliferative activity towards different NiO NPs were in the order of GNi > NNi > RNi > CNi. The present studies demonstrate that simply synthesized NiO can efficiently be used as antiproliferative agents.

The essential oil of Schinus terebinthifolius and its nanoemulsion and isolated monoterpenes: investigation of their activity against Culex pipiens with insights into the adverse effects on non-target organisms.

BACKGROUND: The house mosquito, Culex pipiens L. is a harmful species, widespread in urban areas, and considered the primary enzootic vector of West Nile arbovirus. Widespread insecticide resistance in mosquito populations and the environmental risks and toxicity hazards of chemical pesticides make insecticides an inadequate mosquito control strategy. Seeking ecofriendly tools for mosquito control tools has become necessary. RESULTS: Essential oil (EO) was hydrodistilled from the fruits of Brazilian pepper, Schinus terebinthifolius Raddi and analyzed using gas chromatography-flame ionization detection and gas chromatography-mass spectrometry. An oil-in-water nanoemulsion (particle size 41.3 nm) was developed and characterized from EO using a green low-energy approach. EO, its nanoemulsion and monoterpenes showed mosquitocidal, repellent and acetylcholinesterase inhibitory activities against Cx. pipiens. A nanoemulsion concentration of 30 µl L-1 caused 100% larval mortality after 24 h of exposure, whereas EO, d-limonene and α-phellandrene at 60 µl L-1 caused 100%, 92.4% and 88.2% larval mortality, respectively. The concentration that killed 50% of organisms (LC50 ) for larvae after 24 h ranged between 6.8 and 40.6 µl L-1 . Upon fumigation, 15.0 µl L-1 of nanoemulsion killed 94.5% of adults after 24 h of exposure. LC50 values against adults ranged between 5.3 and 31.2 µl L-1 . EO products exhibited repellence activity at concentrations between 0.5 and 4.0 µl cm-2 . Test materials effectively inhibited the acetylcholinesterase activity of mosquito and were safe toward the non-target organisms Gambusia affinis and Eisenia fetida. CONCLUSION: There is a potential for using S. terebinthifolius EO, its nanoemulsion and monoterpenes as ecofriendly natural mosquitocides.

Chemical composition, insecticidal and biochemical effects of two plant oils and their major fractions against Aedes aegypti, the common vector of dengue fever.

In an attempt to reduce the massive application of the toxic chemical pesticides, essential oils (EOs) of Achillea biebersteinii and Juniperus procera were obtained through hydrodistillation and analyzed using (GC-FID) and (GC-MS). α-terpinene and p-cymene were detected as the major components in the EO of A. biebersteinii, while eugenol and ß-caryophyllene were the major constituents in the EO of J. procera. The plant EOs and major fractions act as considerable mosquitocides against Aedes aegypti L, the common transmitter of Dengue fever. The EOs and major fractions were tested at 6.25, 12.5, 25, 50 and 100 µl/l. Insect mortality was time and dose-dependent, and the adult stage was more sensitive than larvae. At a concentration of 50 µl/l, 24 post treatment larval and adult mortality ranged between (40.3 and 89.3%) and (51.4 and 95.6%), respectively. The LC50 values ranged between 12.2 and 70.1 µl/l against larvae and between 10.1 and 63.12 µl/l against adults. All of the crude EOs were more potent than their major fractions. Eugenol and ß-caryophyllene showed strong mosquitocidal activity than p-cymene and α-terpinene. The corrected percentage mortality was increased over time with all of the test materials. In terms of lethal time required to kill 50% of the population (LT50), a concentration of 100 µl/l of J. procera EO showed LT50 values of 2.3 and 1.7 h against larvae and adult, respectively. The EOs induced considerable inhibition of acetylcholinesterase activity, where J. procera crude oil (IC50 = 13.12mM) and eugenol (IC50 = 19.65mM) were the most potent. Results proved that the test plant oils and their major fractions could be developed as natural pest control agents to control A. aegypti.

Chemical profile, mosquitocidal, and biochemical effects of essential oil and major components of Dysphania ambrosioides against Culex quinquefasciatus Say.

To seek new mosquito control agents while avoiding the environmental impacts and toxicity hazards of conventional pesticides, the essential oil of Dysphania ambrosioides was obtained by hydrodistillation and analysed using GC-FID and GC-MS. The compounds 1-methyl-4-(1-methylethyl)-2,3-dioxabicyclo[2.2.2]oct-5-ene (cis-ascaridole), 1-methyl-4-(1-methylethyl) benzene (р-cymene), and 1-isopropyl-4-methyl-1,3-cyclohexadiene (p-mentha-1,3-diene also known as α-terpinene) were identified as the major components. The EO and the major fractions showed remarkable mosquitocidal activity against third instar larvae and adults of Culex quinquefasciatus Say. The oil and fractions were assayed at 3.125, 6.25, 12.5, 25, and 50 µl/l. Mortality was time- and dose-dependent. At 24 h post-exposure at an assayed concentration of 50 µl/l, the larval and adult mortalities ranged between 80.11-100% and 91.22-100%, respectively. Strong larvicidal and adulticidal activities were recorded in the cases of the crude oil and cis-ascaridole. The LC50 values after 24 h of treatment ranged between 6.2-20.1 µl/l and 5.1-13.9 µl/l against larvae and adults, respectively. The corrected percentage mortalities increased over time with the tested plant oil and the major fractions relative to the control. The time required to achieve 50% mortality (LT50) decreased remarkably with all treatments. The tested EO and major fractions effectively inhibited larval acetylcholinesterase activity with IC50 values ranging from 8.44 to 64.80 mM compared with 2.08 × 10-3 mM for the reference standard, methomy. The results indicate the potential of developing natural mosquitocides against C. quinquefasciatus based on the tested EO and its major fractions. Graphical abstract.

Comparing six mathematical link function models of the antifeedant activity of lesser grain borer exposed to sub-lethal concentrations of some extracts from calotropis procera.

In the present study, Probit, Cauchy Fractional and three types of Log methods, i.e., Logit, Log-log, and Complementary log-log were employed to model the feeding deterrence of the lesser grain borer, Rhyzopertha dominica (F) (Coleoptera: Bostrichidae), when fed latex protein, crude flavonoid fraction, 3-O-rutinosides of quercetin, kaempferol and isorhamnetin, isolated from Calotropis procera (Ait.) (Gentianales: Asclepiadaceae). A nutritional study with treated flour discs at sub-lethal concentrations indicated that the tested natural products negatively affected the feeding behavior of the lesser grain borer, causing high feeding deterrent indices. Our results assure that Probit, Logit and Clog-log model the feeding deterrent indices with high goodness of fit. The models aim to support the management of the test insect when fed grains treated with sub-lethal doses of the tested phytochemicals in order to develop a viable, precise and long-term strategy to minimize the excessive reliance on the chemical pesticides currently in use.