Changes in the contour of karyology and histoarchitecture of the primary respiratory organ in the fish Oreochromis mossambicus (Peters, 1852) inhabiting the polluted estuarine ecosystem.

The wetland ecosystem (WE) is subject to pollution by many anthropogenic activities, including domestic and industrial effluents. These effluents may contain toxic heavy metals that can interact within the aquatic ecosystem and have a capacity to disturb the metabolic activities, histological profile, and genetic structure and functions in aquatic species inhabiting the environment. The present study observed the karyological and histological alterations in gills of the freshwater fish, Mozambique tilapia, Oreochromis mossambicus in two different sublethal concentrations (1% and 3%) of heavy metals in 7, 15, and 30 days of experimental periods. The heavy metals induced various structural damages such as ring chromosome, sister chromatid exchange, acrocentric association region, condensed chromosomal morphology, heterochromatin region, and nucleolar organizer region in the chromosomes of O. mossambicus treated with 1% and 3% sublethal concentrations of water sample collected from Pallikaranai wetland ecosystem. Gills exposed to 1% and 3% effluent exhibited several variations in the respiratory surfaces of gill arches or lamellae in the light and scanning microscopical study. The gills exposed to 1% concentration for 30 days showed marked necrosis, and the secondary lamellae showed the lamellar membrane's dissolution. Exposure of gills to raw effluent in the field condition was observed in the presence of Cd, Pb, Cr, Cu, and Zn. Thus, this present study shows the environmental deterioration by heavy metal pollution on the structure of the gills in tilapia.

Phytochemical analysis and fabrication of silver nanoparticles using Acacia catechu: An efficacious and ecofriendly control tool against selected polyphagous insect pests.

Globally, the farmers are struggling with polyphagous insect pest, and it is the number one enemy of agri-products, which made plenty of economic deterioration. Spodoptera litura and Helicoverpa armigera are the agronomically important polyphagous pests. Most of the farmers are predominately dependent on synthetic chemical insecticides (SCIs) for battle against polyphagous pets. As a result, the broad spectrum usage of SCIs led a lot of detrimental outcomes only inconsequently the researchers search the former-friendly phyto-pesticidal approach. In the present investigation, leaf ethanol extract (LEE) and silver nanoparticles (AgNPs) of A. catechu (Ac) were subjected to various spectral (TLC, CC, UV, FTIR, XRD and SEM) analyses. Larval and pupal toxicity of A. catechu Ac-LEE and Ac-AgNPs were tested against selected polyphagous insect pests. The significant larval and pupal toxicity were experimentally proven, and the highest toxicity noticed in AgNPs than Ac-LEE. The larval and pupal toxicity of Ac-AgNPs tested against S. litura and H. armigera LC50/LC90 values were 71.04/ 74.78, 85.33/ 88.91 µg/mL and 92.57/ 96.21 and 124.43/ 129.95 µg/mL respectively. Ac-AgNPs could be potential phyto-pesticidal effectiveness against selected polyphagous insect pests. In globally, it is significantly sufficient ratification giving towards the prevention of many unauthorized SCPs.

Probing of heavy metals in the feathers of shorebirds of Central Asian Flyway wintering grounds.

The study is intended to deliver the incidence of heavy metals in the feathers of shorebirds from two important Central Asian Flyway (CAF) migratory shorebirds wintering sites such as the Point Calimere Wildlife Sanctuary (PWLS) and Pichavaram Mangrove Forest (PMF), India. Feathers of fifteen species of shorebirds and seven different metals viz., Cu, Cr, Co, Pb, Hg, Ni and Zn were analyzed. Zn was highest in Dunlin, Little-ringed Plover, Marsh Sandpiper, and Common sandpiper, Ni showed highest in Little ringed plover, and Common sandpiper, Co, Cr, and Cu were maximum in Little stint, Marsh sandpiper, and Dunlin, respectively. The Hg was higher in Black-winged stilt, Common redshank, Curlew Sandpiper, Eurasian curlew, Lesser Sand-plover, Temminck's stint, Kentish plover, Spotted redshank, and Wood sandpiper, the Pb found highest in Kentish plover, Painted stork, Spotted redshank, Wood sandpiper, Eurasian Curlew, and Lesser sand-plover. The concentration of metals showed significant variations among the species of shorebirds studied (P < 0.001). The mercury negatively correlated with the other metals than the other six metals studied in both the wetlands. The order of metal concentration in the feathers of shorebirds was Zn > Ni > Co > Cr > Cu > Pb > Hg. Nevertheless, the current study revealed that the level of metals in the shorebirds is alarming; since the PWLS and PMF are located along the CAF routes, it needs intensive studies on various pollutions to manage both the resident as well as migratory shorebirds.

Entomofaunal survey and larvicidal activity of greener silver nanoparticles: A perspective for novel eco-friendly mosquito control.

The entomofaunal survey and its toxicity of Blumea mollis (Asteraceae) leaf aqueous extract-mediated (Bm-LAE) silver nanoparticles (AgNPs) were assessed against selected human vector mosquitoes (HVMs). A total of 1800 individuals of 29 species belongs to 7 genera were identified. Month-wise and Genus-wise abundance of HVMs larval diversity were calculated and one-way ANOVA statistically analyzed the average physico-chemical characteristics. The relationship between physicochemical characteristics and HVMs larvae in KWS was interpreted. The total larval density and container index were 23530.18 and 1961.85 examined against 10 different containers. Various spectroscopic and microscopic investigation characterized Bm-AgNPs. The Bm- AgNPs tested against HVMs larvae, the predominant LC50/LC90 values of 18.17/39.56, 23.45/42.49 and 21.82/40.43 µg/mL were observed on An. subpictus Cx. vishnui and Ae. vittatus, respectively. The findings of this investigation, improperly maintained drainages, containers and unused things in study sites, are engaged to HVMs development. This will be essential for designing and implementing HVMs control. The larval toxic potentiality of Bm- AgNPs had a prompt, inexpensive and compelling synthesis of multi-disperse action against HVMs.

Larvicidal and repellant effects of Jussiaea repens (L.) leaf ethanol extract and its major phyto-constituent against important human vector mosquitoes (Diptera: Culicidae).

Jussiaea repens (L.) leaf ethanol extract (LEE) and its major phyto-compound (MPC) have effects against larvae and adults of dengue, malarial, and filarial vectors. Total larval death rates were recorded from LEE and MPC has significant larval killing activity with LC50/LC90 values of Ae. albopictus, An. stephensi, and Cx. quinquefasciatus that were 118.3/229.9, 116.1/216.8, 114.4/213.5 and 17.7/27.5, 15.6/25.4 and 12.3/21.1 µg/ml, respectively. A best repellent activity was ascertained at 3.057 mg/cm2 concentration of LEE and MPC provided 100% protection upto 240 min against selected human vector mosquitoes (HVMs). The functional groups were confirmed by FT-IR analysis and their presence in ethanol extract and mass spectral analysis: 4-piperidineacetic acid, 1-acetyl-5-ethyl-2-[3-(2-hydroxyethyl]-1H-indol-2-yl]-á-methyl-, methyl ester compound was identified in the LEE. The results obtained suggest that J. repens LEE and its MPC were important and responsible for health protection and control of HVMs.

Spectroscopic investigation of biosynthesized nickel nanoparticles and its larvicidal, pesticidal activities.

Methanolic extract of Cocos nucifera (C. nucifera) was collected using Soxhlet apparatus. C. nucifera methanolic extract was used to prepare Nickel nanoparticles (Ni NPs). Eco-friendly synthesized Ni NPs were confirmed by several analytical techniques such as UV-Visible spectroscopy (UV-Vis), Fourier Transform Infrared spectroscopy (FT-IR), X-ray diffraction (XRD), Scanning Electron Microscope (SEM), Energy Dispersive X-ray analysis (EDAX), Transmission Electron Microscope (TEM) and Zeta potential. The obtained results infer that green synthesized Ni NPs are in cubical shape with an average particle size of 47nm. Synthesized Ni NPs were subjected to pesticidal activity against agricultural pest Callasobruchus maculates (C. maculates) which resulted in 97.31% mortality. These results were compared with commercially available standard Azadirachtin. Also we have studied larvicidal activity against Aedes ageypti (A. ageypti) larvae which resulted in LC 50 and LC 90 value of 259.24, 446.99ppm respectively and the result proved to be significant which were processed by ANOVA LSD Tukey's test.

Mosquitocidal properties of Solanum trilobatum L. (Solanaceae) leaf extracts against three important human vector mosquitoes (Diptera: Culicidae).

OBJECTIVE: To determine the larvicidal and pupicidal activites of Solanum trilobatum (S. trilobatum) leaf extracts against Aedes aegypti (Ae. aegypti), Culex quinquefasciatus (Cx. quinquefasciatus) and Anopheles stephensi (An. stephensi). METHODS: The larvicidal and pupucidal was determined at five different concentrations of 50, 100, 150, 200 and 250 ppm. Percentage of larval mortality was assessed after 48 h. RESULTS: Methanol extracts of S. trilobatum was found to be more susceptible against the larvae of Ae. aegypti, Cx. quinquefasciatus and An. stephensi at 250 ppm with a LC50 value of 125.43, 127.77 and 116.64 ppm respectively. Leaf methanol extracts of S. trilobatum also exhibited pupicidal and adult emergence properties. CONCLUSIONS: These results suggested that the leaf extracts of S. trilobatum showed potential to be used as an ideal ecofriendly approach for the control of the Ae. Aegypti, Cx. quinquefasciatus and An. stephensi.

Larvicidal, ovicidal and pupicidal activities of Gliricidia sepium (Jacq.) (Leguminosae) against the malarial vector, Anopheles stephensi Liston (Culicidae: Diptera).

OBJECTIVE: To investigate the potentiality of mosquitocidal activity of Gliricidia sepium (G. sepium) (Jacq.) (Leguminosae). METHODS: Twenty five early third instar larvae of Anopheles stephensi (An. stephensi) were exposed to various concentrations (50-250 ppm) and the 24 h LC(50) values of the G. sepium extract was determined by probit analysis. The ovicidal activity was determined against An. stephensi to various concentrations ranging from 25-100 ppm under laboratory conditions. The eggs hatchability was assessed 48 h post treatment. The pupicidal activity was determined against An. stephensi to various concentrations ranging from 25-100 ppm. Mortality of each pupa was recorded after 24 h of exposure to the extract. RESULTS: Results pertaining to the experiment clearly revealed that ethanol extract showed significant larvicidal, ovicidal and pupicidal activity against the An. stephensi. Larvicidal activity of ethanol extracts of G. sepium showed maximum mortality in 250 ppm concentration (96.0±2.4)%. Furthermore, the LC(50) was found to be 121.79 and the LC(90) value was recorded to be 231.98 ppm. Ovicidal activity of ethanol extract was assessed by assessing the egg hatchability. Highest concentration of both solvent extracts exhibited 100% ovicidal activity. Similarly, pupae exposed to different concentrations of ethanol extract were found dead with 58.10% adult emergence when it was treated with 25 ppm concentration. Similarly, 18.36 (n=30; 61.20%); 21.28(70.93) and 27.33(91.10) pupal mortality was recorded from the experimental pupae treated with 50, 75 and 100 ppm concentration of extracts. Three fractions have been tested for their larvicidal activity of which the Fraction 3 showed the LC(50) and LC(90) values of 23.23 and 40.39 ppm. With regard to the ovicidal effect fraction 3 showed highest ovicidal activities than the other two fractions. Furthermore, there were no hatchability was recorded above 50 ppm (100% egg mortality) in the experimental group. Statistically significant pupicidal activity was recorded from 75 ppm concentration. CONCLUSIONS: From the results it can be concluded the crude extract of G. sepium is an excellent potential for controlling An. stephensi mosquito. It is apparent that, fraction 3 possess a novel and active principle which could be responsible for those biological activities.

Biological activities of Solanum pseudocapsicum (Solanaceae) against cotton bollworm, Helicoverpa armigera Hübner and armyworm, Spodoptera litura Fabricius (Lepidotera: Noctuidae).

OBJECTIVE: To evaluate the antifeedant, insecticidal and growth inhibition activities of Solanum pseudocapsicum (S. pseudocapsicum) seed extracts against Spodoptera litura (S. litura) and Helicoverpa armigera (H. armigera). METHODS: Hexane, diethyl ether, dichloromethane and ethyl acetate seed extracts were prepared and tested for antifeedant, insecticidal and growth inhibitory activities against fourth instar larvae of S. litura and H. armigera. RESULTS: Ethyl acetate extract showed promising antifeedant and insecticidal activities against S. litura and H. armigera. Percentage of deformed larvae, pupae and adults were maximum in treatment of ethyl acetate extract. Percentage of successful adult emergence was deteriorated by seeds on extract treated larvae. CONCLUSIONS: Ethyl acetate extracts of S. pseudocapsicum, showed higher efficiency of antifeedant, insecticidal and growth inhibition activities. Hence, it can be used to controll agricultural insect pests, S. litura and H. armigera.