Goutam Chandra

Biosorption of heavy metals from industrial waste water by Geobacillus thermodenitrificans.

The metal binding capacity of the thermophilic bacteria Geobacillus thermodenitrificans isolated from Damodar river, India was assessed using synthetic metal solutions and industrial waste water. Biosorption preference of dead biomass of G. thermodenitrificans for the synthetic metal solutions was in the following order Fe(+3)>Cr(+3)>Co(+2)>Cu(+2)>Zn(+2)>Cd(+2)>Ag(+)>Pb(+2). It reduced the concentration of Fe(+3) (91.31%), Cr(+3) (80.80%), Co(+2) (79.71%), Cu(+2) (57.14%), Zn(+2) (55.14%), Cd(+2) (49.02%), Ag(+) (43.25%) and Pb(+2) (36.86%) at different optimum pH within 720 min. When this strain was applied in the industrial waste water biosorption preference was in the following order Fe(+3)>Cr(+3)>Cd(+2)>Pb(+2)>Cu(+2)>Co(+2)>Zn(+2)>Ag(+) and concentrations reduced up to 43.94% for Fe(+3), 39.2% for Cr(+3), 35.88% for Cd(+2), 18.22% for Pb(+2), 13.03% for Cu(+2), 11.43% for Co(+2), 9.02% for Zn(+2) and 7.65% for Ag(+) within 120 min.

Antibacterial potentiality of Argemone mexicana solvent extracts against some pathogenic bacteria

The sensitivity of two Gram positive (Staphylococcus aureus and Bacillus subtilis) and two Gram negative (Escherichia coli and Pseudomonas aeruginosa) pathogenic multi-drug resistant bacteria was tested against the crude extracts (cold aqueous, hot aqueous, and methanol extracts) of leaves and seeds of Argemone mexicana L. (Papaveraceae) by agar well diffusion method. Though all the extracts were found effective, yet the methanol extract showed maximum inhibition against the test microorganisms followed by hot aqueous extract and cold aqueous extract.

Antibacterial activity of some medicinal plant extracts

Antibacterial activity of hot aqueous and methanolic extracts prepared from six plants (Terminallia chebula, Terminallia bellerica, Phyllanthus emblica, Punica granatum, Lawsonia alba and Mikania micrantha) used in traditional folk medicines of India were screened against five pathogenic bacteria (Staphylococcus aureus MTCC 2940, Bacillus subtilis MTCC 441, Escherichia coli MTCC 739, Proteus vulgaris MTCC 426 and Enterobacter aerogenes MTCC 111). The highest antibacterial potentiality was exhibited by the methanolic leaf extract of T. chebula, followed by the aqueous fruit extract of T. bellerica. The leaf extract of T. chebula can be considered to be as equally potent as the most effective antibiotics, such as ciprofloxacin, gentamycin, kanamycin, ofloxacin and cephalexin. A sensitivity test performed with commonly used sensitivity test disks resulted in the appearance of multiple drug resistance phenotypes of the bacteria tested. A comparision of data in the inhibition zones of pathogenic bacteria showed that gentamycin, ofloxacin, kanamycin and tobramycin were effective against all of the bacterial strains tested.

Mosquito larvicidal activities of Solanum villosum berry extract against the dengue vector Stegomyia aegypti.

BackgroundVector control is facing a threat due to the emergence of resistance to synthetic insecticides. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. Although several plants have been reported for mosquitocidal activity, only a few botanicals have moved from the laboratory to field use, because they are poorly characterized, in most cases active principals are not determined and most of the works are restricted to preliminary screening. Solanum villosum is a common weed distributed in many parts of India with medicinal properties, but the larvicidal activity of this plant has not been reported so far.MethodsAqueous and polar/non-polar solvent extract of fresh, mature, green berries of S. villosum was tested against Stegomyia aegypti, a common vector of dengue fever. A phytochemical analysis of chloroform:methanol extract was performed to search for the active toxic ingredient. The lethal concentration was determined (log probit analysis) and compared with Malathion. The chemical nature of the active substance was also evaluated following ultraviolet-visual (UV-Vis) and infrared (IR) analysis.ResultsIn a 72 hour bioassay experiment with the aqueous extract, the highest mortality was recorded in 0.5% extract. When the mortality of different solvent extracts was compared, the maximum (p < 0.05) mortality was recorded at a concentration of 50 ppm of chloroform:methanol extract (1:1, v/v). The larvicidal activity was lower when compared with the chemical insecticide, Malathion (p < 0.05). Results of regression analysis revealed that the mortality rate (Y) was positively correlated with the period of exposure (X) and the log probit analysis (95% confidence level) recorded lowest value (5.97 ppm) at 72 hours of exposure. Phytochemical analysis of the chlororm:methanol extract reported the presence of many bioactive phytochemicals. Two toxic compounds were detected having Rf = 0.82 (70% and 73.33% mortality in 24 and 48 hours, respectively) and Rf = 0.95 (40% and 50% mortality in 24 and 48 hours, respectively). IR analysis provided preliminary information about the steroidal nature of the active ingredient.ConclusionS. villosum offers promise as potential bio control agent against S. aegypti particularly in its markedly larvicidal effect. The extract or isolated bioactive phytochemical could be used in stagnant water bodies for the control of mosquitoes acting as vector for many communicable diseases.

Mosquito larvicidal and antimicrobial activity of synthesized nano-crystalline silver particles using leaves and green berry extract of Solanum nigrum L. (Solanaceae: Solanales).

Silver nanoparticles (AgNPs) that are synthesized by using aqueous extracts of Solanum nigrum L., is a simple, non-toxic and ecofriendly green material. The present study is based on assessments of the larvicidal and antimicrobial activities of the synthesized AgNPs from fresh leaves, dry leaves and green berries of S. nigrum against larvae of Culex quinquefasciatus and Anopheles stephensi and four human pathogenic and five fish pathogenic bacteria respectively. The synthesized nanoparticles are characterized with UV-vis spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR) and transmission electron microscope (TEM) analysis. The nanoparticles are spherical to polyhedral in shape with size of 50-100nm (average size of 56.6nm). In larvicidal bioassay with synthesized AgNPs, highest mortality are observed at 10ppm against An. stephensi with LC50 values of 1.33, 1.59, 1.56ppm and LC90 values of 3.97, 7.31, 4.76ppm for dry leaves, fresh leaves and berries respectively. Antibacterial activity test reveals better results against fish pathogenic bacteria than human pathogenic bacteria. Non target organism like Toxorhynchites larvae (mosquito predator), Diplonychus annulatum (predatory water-bug) and Chironomus circumdatus larvae (chironomid) are also exposed to respective lethal concentrations (to mosquito larvae) of dry nanoparticles and no abnormality in the non target organisms are recorded. These results suggest that the synthesized AgNPs of S. nigrum have the potential to be used as an ideal eco-friendly compound for the control of the mosquito larvae and harmful bacteria.

Mosquito larvicidal activity of some common spices and vegetable waste on Culex quinquefasciatus and Anopheles stephensi

OBJECTIVE To investigate the larvicidal activities of crude and chloroform: methanol (1:1 v/v) extracts of some common spices (Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa) and vegetable waste (Solanum tuberosum germinated tuber) against Anopheles stephensi and Culex quinquefasciatus mosquito larvae. METHODS Larval mortality of above mosquito species were observed after 24, 48 and 72 h of exposure to five concentrations of aqueous extract (0.1%, 0.2%, 0.3%, 0.4% and 0.5%) and four concentrations (25, 50, 75 ppm) of chloroform: methanol (1:1 v/v) extract. The lethal concentration of individual spices or vegetable waste was determined by log-probit analysis (at 95% confidence level) and effect of crude and chloroform: methanol (1:1 v/v) extracts were recorded on non target organisms. RESULTS Relative mortality rate of both larval mosquito species were recorded in the following sequences: Cuminum cyminum >Allium sativum >Zingiber offinale, Curcuma longa >Solanum tuberosum germinated tuber for crude extract, and efficacy of chloroform: methanol (1:1 v/v) extract were as follows: Curcuma longa >Zingiber offinale >Solanum tuberosum germinated tuber >Cuminum cyminum >Allium sativum. CONCLUSIONS Crude and chloroform: methanol (1:1 v/v) extract of Cuminum cyminum, Allium sativum, Zingiber offinale, Curcuma longa and Solanum tuberosum germinated tuber can be recommended effectively in mosquito control programmes at very low concentrations. No mortality and other abnormalities were noticed on non target organisms and further studies are needed to investigate the chemical structure of active principal which are responsible for larvicidal activity.

Mosquito larvicidal and antimicrobial activity of protein of Solanum villosum leaves

BackgroundMosquitoes are associated with the transmission of malaria, dengue, Japanese encephalitis, filariasis and other viral diseases throughout the globe, apart from being a nuisance pest. Biological control alone or as a part of integrated vector management stands to be a better alternative to the chemical controls aimed against pest mosquitoes. At the same time it is necessary to control bacteria by synthetic or natural means (plant products). Hence the present study was designed to screen the effect of mosquito larvicidal and antimicrobial activitiy of protein isolated from matured leaves of Solanum villosum against mosquito immatures and some pathogenic bacteria.MethodsAqueous solvent extract of fresh mature leaves of S. villosum was tested against 3rd instar larvae of Anopheles stephensi, Culex quinquefasciatus and Stegomyia aegypti mosquitoes and against four pathogenic bacteria. The protein fraction was isolated and tested for mosquitocidal and antibacterial activities. Amino acid analysis was performed on isolated protein using PICO.TAG amino acid system. SDS-PAGE was also done to detect the bands of amino acid on the basis of their molecular weights.ResultsProteins isolated from mature leaves of S. villosum were found to have larvicidal and antimicrobial properties. Analysis of the isolated protein identified fifteen amino acids of which eight were essential amino acids. SDS-PAGE detected seven bands corresponding to different molecular weights in the range of 69–109 KDa.ConclusionProteins of mature leaves of S. villosum exhibited moderate larvicidal and antimicrobial activities. The study provides considerable scope in exploiting local indigenous resources for isolation of antimicrobial and mosquito larvicidal proteins.

Larvicidal activity of Dregea volubilis and Bombax malabaricum leaf extracts against the filarial vector Culex quinquefasciatus.

OBJECTIVE To analyze the larvicidal activity of two plant leaf powder and leaf-extracts, Dregea volubilis and Bombax malabaricum against Culex quinquefasciatus. METHODS The larvicidal bioassay was done for powdered leaves of Dregea volubilis and Bombax malabaricum individually and their methanol extracts against first-, second-, third- and fourth-instar larval forms of Culex quinquefasciatus. Mortality rate was recorded after 24, 48 and 72 h of post-exposure. LC(50) and LC(90) values were calculated at different time intervals for third instar larvae. RESULTS All the graded concentration (0.1%, 0.2%, 0.3%, 0.4%, 0.5%) of powdered leaves showed significant (P <0.05) larval mortality. The mortality rate was higher in 50 ppm doses of methanolic extracts of both the plants against Culex quinquefaciatus. The corresponding LC(50) values were 56.97 ppm and 48.85 ppm, respectively after 24 h of exposure. There is no mortality of non-target organism such as Chironomous circumdatus, Oreochromis niloticus niloticus and Diplonichus annulatum within 72 h of post exposure to 0.1%, 0.2%, 0.3% crude powdered leaves and methanolic extracts of both the two individual plants under the laboratory condition. The results of preliminary qualitative phytochemical analysis of both the plants revealed the presence of many bioactive principles such as steroids, tannins, flavonoids, triterpenoids, saponins, etc. that may be responsible for their bio-control potentiality. CONCLUSIONS The results have shown potential and eco-friendly use of both plant extracts against larva of Culex quinquefasciatus for the first time.

Isolation and identification of bioactive antibacterial components in leaf extracts of Vangueria spinosa(Rubiaceae)

OBJECTIVE The column chromatographic fraction of ethyl acetate (EA1, EA2, EA3, EA4 and EA5) leaf extracts of Vangueria spinosa (V. spinosa) were screened for antibacterial activity and phytochemical analysis. METHODS EA3 fraction was isolated and identified by column chromatography, thin layer chromatography, spectral data analysis and phytochemical screening were used for analysis. RESULTS EA3 fraction was significantly active at 4 to 64 mg/L against Staphylococcus aureus, Escherichia coli, Klebsiella pneumoniae and Pseudomonas aeruginosa with minimum inhibitory concentration of 1.5625 to 3.1250 mg/mL. The active fraction (EA3) revealed the presence of flavonoid with retention factor value (R(f)) of 0.39. The active antibacterial agent in the most potent fraction (EA3) was isolated and identified as flavonoid (-)-epicatechin-3-O-β-glucopyranoside by thin layer chromatography (TLC) and phytochemical screening. EA1 and EA2 show inhibitory activity at 4 to 64 mg/L against Staphylococcus aureus only where as fraction EA4 and EA5 do not shows any inhibitory activity within that range of concentration against any bacteria. CONCLUSIONS The results support the ethnomedicinal use of leaf of V. spinosa for the treatment of bacterial diseases.

A review on Anopheles subpictus Grassi--a biological vector.

Anopheles subpictus is a complex of four isomorphic sibling species A, B, C and D and is recognized as a primary vector of malaria, a disease of great socio-economic importance, in Australasian Zone, Celebes, Portuguese Timor and South East Asia and a secondary vector in Sri Lanka. This species is also a vector of some helminth and arboviruses. This species has been reported so far from nineteen countries of the Oriental and Australasian Zones. An. subpictus complex is the most abundant anopheline in most parts of the Indian subcontinent, with a widespread distribution eastwards and southwards to Papua New Guinea, westwards to Iran and northwards to China. Resistance to insecticide is alarming in many parts of the world. Different aspects of this important mosquito species including attempts related to its control have been discussed which will be highly useful to carry out further research.