Pachiappan Perumal

Effect of sub-acute exposure to nickel nanoparticles on oxidative stress and histopathological changes in Mozambique tilapia, Oreochromis mossambicus

The aim of the present study was to assess the oxidative stress, antioxidant response and histopathological changes of nickel nanoparticles (Ni NPs) exposure (14 days) in Mozambique tilapia, Oreochromis mossambicus. Ni NPs were synthesized by metal salt reduction method and characterized by X-ray diffraction (XRD) and Transmission electron microscopy (TEM). The XRD peaks at 44°, 51° and 76° were indexed to the (111), (200) and (220) Braggs reflections of cubic structure of Nickel, respectively. The crystallite sizes were calculated using Scherrers formula applied to the major intense peaks and found to be the size of 56nm. TEM images showed that the synthesized Ni NPs are spherical in shape. Biochemical analysis indicated that the superoxide dismutase (SOD), catalase (CAT) and peroxidase (POD) activity was significantly affected by Ni NPs treated O. mossambicus. Reduced antioxidant enzymes and the contents of antioxidants were lowered in the liver and gills of fishes treated with Ni NPs. After 14 days of exposure, a significant accumulation of Ni in the Ni NPs in experimental group was observed in the gill and skin tissues, with the highest levels found in the liver. Ni NPs exposed fish showed nuclear hypertrophy (NH), nuclear degeneration (ND), necrosis (NC) and irregular-shaped nuclei were observed in liver tissue. The hyperplasia of the gill epithelium (GE), lamellar fusion of secondary lamellae (LF), dilated marginal channel (MC), epithelial lifting (EL) and epithelial rupture were observed in gill tissue. Degeneration in muscle bundles (DM), focal area of necrosis (NC) vacuolar degeneration in muscle bundles (VD), edema between muscle bundles (ED) and splitting of muscle fibers were noticed in skin tissue. Further ecotoxicological evaluation will be made concerning the risk of Ni NPs on aquatic environment.

Structural characterization, antioxidant and in vitro cytotoxic properties of seagrass, Cymodocea serrulata (R.Br.) Asch. & Magnus mediated silver nanoparticles

The present study pertains to the synthesis, structural elucidation, antioxidant and in vitro cytotoxic properties of silver nanoparticles (AgNPs) from marine angiosperm, Cymodocea serrulata aqueous extract (CSAE). The characterization was made through UV-Visible spectroscopy (UV-Vis), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), zeta potential and dynamic light scanning (DLS) analyses. The UV-Vis spectrum resulted in a strong surface plasmon resonance (SPR) at 430 nm. The average crystalline size of the AgNPs was predicted through XRD peaks that indicated the 2 theta values of 37.84°, 44.06°, 64.42° and 77.74° for Braggs refraction index. The functional groups responsible for the bio-reduction of Ag(+) into Ag(0) were focused through FTIR spectrum. The FESEM images showed that the C. serrulata mediated AgNPs (CS-AgNPs) were spherical in shape. DPPH assay revealed the higher free radical scavenging activity in CS-AgNPs, when compared to CSAE. The cytotoxicity assay on the cervical cancer (HeLa) and African green monkey kidney (Vero) cells upon treatment with CSAE: 107.7 & 124.3 μgml(-1) and CS-AgNPs: 34.5 & 61.24 μgml(-1), respectively showed good inhibition rate. These findings highlight the fact that C. serrulata could be a potential source for developing potent drugs and further studies are needed.

Larvicidal activity of titanium dioxide nanoparticles synthesized using Morinda citrifolia root extract against Anopheles stephensi, Aedes aegypti and Culex quinquefasciatus and its other effect on non-target fish

Objective To assess the larvicidal activity of titanium dioxide nanoparticles (TiO2NPS) synthesized from the root aqueous extract of Morinda citrifolia (M. citrifolia) against the larvae of Anopheles stephensi (An. stephensi), Aedes aegypti (Ae. aegypti) and Culex quinquefasciatus (Cx. quinquefasciatus).

Structural characterization and evaluation of mosquito-larvicidal property of silver nanoparticles synthesized from the seaweed, Turbinaria ornata (Turner) J. Agardh 1848

Abstract The silver nanoparticles synthesized from Turbinaria ornata (To-AgNPs) showed spherical with crystalline nature (20–32 nm) was evaluated against fourth instar larvae of three mosquitoes. The maximum activity of To-AgNPs was recorded on Aedes aegypti followed by Anopheles stephensi and Culex quinquefasciatus with the following lethal concentration values (μg/ml): LC50 of 0.738, 1.134, and 1.494; and LC90 of 3.342, 17.982, and 22.475, respectively. The obtained respective values (μg/ml) vis-a-vis aqueous extract (To-AE) were: 2.767 and 40.577; 4.347 and 158.399, and 7.351 and 278.994. The findings revealed that To-AgNPs could form a base for the development of an eco-friendly, low-cost pesticide.

GC–MS analysis of bioactive components and synthesis of gold nanoparticle using Chloroxylon swietenia DC leaf extract and its larvicidal activity

A rapid bio-reduction of chloroauric acid (HAuCl4) was achieved by Chloroxylon swietenia DC leaf extract (CSLE), which resulted in the formation of well dispersed C. swietenia gold nanoparticles (CSGNPs). The formation of GNPs was confirmed by color changes from yellowish green to purple and their characteristic peak at 545 nm. The characterization of synthesized CSGNPs was made through X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), high resolution transmission electron microscopy (HRTEM) equipped with energy dispersive X-ray spectroscopy (EDX) followed by size and zeta potential analyses. The GC-MS profile of C. swietenia methanolic leaf extract (CSMLE) resulted 20 phytocomponents, among those heptacosanoic acid, 25-methyl-, methyl ester (C29H58O2) attributes highest peak area. The efficiency of the synthesized CSMLE, CSGNPs and CSLE were tested against fourth instar larvae of malarial and dengue vector, which resulted more substantial upshot than with leaf extract treated. The Lethal concentration (LC50) values of CSMLE, CSGNPs and CSLE were found to be 0.509, 0.340, 0.423 ppm and 0.602, 0.188, 0.646 ppm on Aedes aegypti and Anopheles stephensi, respectively. The findings form an important baseline information proceeding biologically innocuous biopesticide for controlling the malarial and dengue vectors.

Response of three cyprinid fish species to the Scavenger Deterrent Factor produced by the mutualistic bacteria associated with entomopathogenic nematodes.

The symbiotic bacteria, Photorhabdus and Xenorhabdus associated with entomopathogenic nematodes (EPNs) in the genera Heterorhabditis and Steinernema, respectively, produce a compound(s) called the Scavenging Deterrent Factor (SDF). SDF deters a number of terrestrial insect scavengers and predators and one bird species from feeding on host insects killed by the nematode-bacterium complex but has not been tested against aquatic vertebrates. Moreover, the Heterorhabditis-Photorhabdus association is believed to have evolved in an aquatic environment. Accordingly, we hypothesized that SDF will deter fish from feeding on nematode-killed insects and tested the responses of three omnivorous fresh water fish species, Devario aequipinnatus, Alburnoides bipunctatus, and Squalius pursakensis, to SDF in the laboratory. When the fish were exposed to Galleria mellonella larvae killed by the Heterorhabditis- or Steinernema-bacterium complex at 2 or 4days post-infection, all three fish species made several attempts to consume the cadavers but subsequently rejected them. However, all fish species consumed freeze-killed control larvae. In a choice test, when D. aequipinnatus or A. bipunctatus were offered a pair of nematode-killed larvae, both fish species rejected these cadavers; when offered a nematode-killed larva and a freeze-killed larva, both fish species consumed the freeze-killed larva but not the nematode-killed one. In further tests with D. aequipinnatus, there was no significant difference in the number of 2-day-old Bacillus thuringiensis subsp. kurstaki-killed (Btk) larvae consumed compared to freeze-killed larvae, but significantly fewer 4-day-old Btk-killed larvae were consumed compared to freeze-killed larvae. When D. aequipinnatus was fed G. mellonella larvae killed by the symbiotic bacteria, the fish rejected the cadavers. When given freeze-killed or nematode-killed mosquito (Aedes aegypti) larvae, the fish consumed significantly more of the former larvae (99%) compared to the latter (55%). When D. aequipinnatus was placed in a symbiotic cell-free supernatant for 18h, a significant reduction in consumption of freeze-killed larvae compared to cell-free Btk or control broth supernatant was observed. We showed that SDF protects the nematode-killed insects from being consumed by omnivorous fishes and suggests that they will have minimal effects on recycling of EPNs in the aquatic environment.

Lantana camara Linn root extract-mediated gold nanoparticles and their in vitro antioxidant and cytotoxic potentials

Abstract The Lantana camara Linn root extract derived gold nanoparticles (Au NPs) were characterized by Ultraviolet-Visible spectroscopy, X-ray diffraction, fourier transform-infrared, high resolution transmission electron microscopy, selected area electron diffraction pattern and energy dispersive X-ray analyses. In DPPH assay, the inhibitory concentration (IC50) of Au NPs and gallic acid was 24.17 and 5.39 μg/ml, whereas, for cytotoxicity assay, the IC50 of Au NPs was 17.72 and 32.98 μg/ml on MBA-MB-231 and Vero cells, respectively. Thus, the Au NPs possess significant in vitro antioxidant and cytotoxic properties which could be considered as potential alternate for the development of anticancer drug in future.

Zebrafish in the Wild: Microhabitat Use by Zebrafish Danio rerio (Hamilton, 1822) from Karala River of Jalpaiguri District, Northern Bengal, India

The microhabitat preference of zebrafish, Danio rerio from Karala river was investigated. The availability/ preference of microhabitat variables such as (i) distance from the stream bank (ii) water column depth (iii) mesohabitat (iv) water velocity (v) substratum and (vi) subaquatic vegetal cover were quantified based on underwater observations covering a total of 400 m2 of stream area. Microhabitat selectivity was analyzed by comparing the microhabitat availability in the study site and the microhabitat used by fish. Data availability and microhabitats usage pattern were used for calculating habitat availability/preference of D. rerio. In order to test the microhabitat preference of D. rerio the Principal Component Analysis (PCA) and Canonical Correspondence Analysis (CCA) were applied. In PCA the first three components with higher Eigenvalue accounted for about 98.46% of the total variance. The first component axis alone explained 86.33% of the variance with an Eigenvalue of 5.3 with high loadings (>0.7). CCA revealed a clear separation of the D. rerio along the microhabitat variables. Among the thirty two microhabitat variables, the forward selection procedure was found to be positively significant with eighteen microhabitat variables P<0.05. The preference of D. rerio in the studied streams viz: pool, plunge pool and isolated pool; slow flow, moderate flow and fast flow; and the substratum parameters: sand, gravel and leaf litter; depth parameters like Depth 1, Depth 2, Depth 3 and Depth 5; fish cover parameters such as root undercut and distance from bank parameters such as Distance from bank 1, Distance from bank 2 and Distance from bank 3. CCA revealed a clear distribution pattern of the D. rerio along the microhabitat variables.

Ethyl acetate extract from marine sponge Hyattella cribriformis exhibit potent anticancer activity by promoting tubulin polymerization as evidenced mitotic arrest and induction of apoptosis

Background: Marine sponges are important sources of bioactive compounds. Objective: This study investigated the anticancer properties of Hyattella cribriformis ethyl acetate (EA) fraction in various cancer and normal cell lines. Materials and Methods: anticancer assay was carried out in 15 cell lines to evaluate the anticancer potential of the EA fraction. Impact on cell cycle distribution was determined using flow cytometry. The fraction was investigated for interfering microtubules assembly in both in vitro and cellular assay. Further studies were conducted to determine the fraction induced cell death (apoptosis) using calcein/propidium iodide dual staining, activated caspase-3 and phosphorylation of Bcl-2 protein at Ser70. DNA fragmentation assay was performed to confirm the apoptosis. Results: EA fraction exhibited potent inhibition of cancer cell growth and resulted in 50% growth inhibition (GI50) of 0.27 μg/mL in A673 cell line. Sarcoma (MG-63, Saos-2) and ovarian (SK-OV-3 and OVCAR-3) cancer cell lines also showed superior anticancer activity GI50 of 1.0 μg/mL. Colon and breast cancer cell lines exhibited moderate GI compare other cancer cell lines and normal human lung fibroblast showed GI50 of 15.6 μg/mL. EA fraction showed potent G2/M phase arrest in A673 cell line and induced apoptosis at 48 h exposure. EA fraction promoted microtubule polymerization in tubulin polymerization assay and increased level of polymerized tubulin in the HeLa cells. Fraction induced the activation of caspase-3 and phosphorylation of Bcl-2 anti-apoptotic protein. Fraction induced DNA fragmentation in HeLa cells as evidence of apoptosis. Conclusion: Marine sponge H. cribriformis EA fraction exhibited potent anticancer activity through tubulin polymerization and induction of apoptosis.

Sol-Gel Titania Coating Precursors Having Different Anatase-Rutile Transformation Temperature

Titania catalysts have potential applications in synthesis and decomposition of organic compounds, in waste-water treatment and also as photo-electro and photo-chemical devices. Titania coatings are also indicated to be effective as humidity sensors. Anatase phase titania is believed to be preferentially effective in light sensitive applications. Titania gel precursor has been prepared by controlled hydrolysis of titanium isopropoxide in presence of gel modifiers such as acetic acid and diethanolamine. The resultant gel was dried and calcined at different temperatures in the range 200° to l000°C. The dehydroxylation characteristics of the gel and anatase to rutile transformation temperatures are presented. The DEA modified precursor exhibits an anatase to rutile transformation temperature of 600°C, while the acetic acid modified one has a stable anatase phase even at 800°C.