Bioactivity of essential oils of <Emphasis Type="BoldItalic">Zingiber officinalis</Emphasis> and <Emphasis Type="BoldItalic">Achyranthes aspera</Emphasis> against mosquitoes

Due to the global health problems associated with mosquito-borne diseases, over two million people primarily in the tropical countries are at risk. The widely and commonly used chemical method though effective, has some major disadvantages making insect control practically difficult. In view of the above, it is unavoidable to search for new molecules, which are eco-friendly, cheaper, and safer. The present study deals with evaluation of bioactive potential of two commonly occurring plants against mosquitoes presenting an alternative to the conventional chemical methods. Essential oils extracted by steam distillation from rhizome of Zingiber officinalis and leaf and stem of Achyranthes aspera were evaluated for larvicidal, attractant/repellent, and oviposition attractant/deterrent activity against two mosquito species viz. Aedes aegypti and Culex quinquefasciatus. The highest larvicidal activity, i.e., LC₅₀ = 154 ppm and LC₅₀ = 197 ppm for A. aegypti and C. quinquefasciatus, respectively was shown by Z. officinalis. This oil also offers 5-h protection at the concentration of 0.5 mg/cm2 from both mosquito species. The highest oviposition deterrence activity was exhibited by A. aspera stem oil, i.e., 100% and 85.71%, in case of A. aegypti and C. quinquefasciatus, respectively, at the concentration of 0.1%. These results reveal that both these oils have control potential against A. aegypti and C. quinquefasciatus.     

Larvicidal activity of silver nanoparticles synthesized using <Emphasis Type="Italic">Plumeria rubra</Emphasis> plant latex against <Emphasis Type="Italic">Aedes aegypti</Emphasis> and <Emphasis Type="Italic">Anopheles stephensi</Emphasis>

In the present study activity of silver nanoparticles (AgNPs) synthesized using Plumeria rubra plant latex against second and fourth larval instar of Aedes aegypti and Anopheles stephensi was determined. Range of concentrations of synthesized AgNps (10, 5, 2.5, 1.25, 0.625, 0.3125 ppm) and aqueous crude latex (1,000, 500, 250, 125, 62.50, 31.25 ppm) were tested against larvae of A. aegypti and A. Stephensi. The synthesized AgNps from P. rubra latex were highly toxic than crude latex extract in both mosquito species. The LC₅₀ values for second and fourth larval instars after 24 h of crude latex exposure were 1.49, 1.82 ppm against A. aegypti and 1.10, 1.74 ppm against A. stephensi respectively. These figures were 181.67, 287.49 ppm against A. aegypti and 143.69, 170.58 ppm against A. stephensi respectively for crude latex extract. The mortality rates were positively correlated with the concentration of AgNPs. The characterization studies of synthesized AgNPs by UV–Vis spectrophotometry, transmission electron microscopy (TEM), Particle size analysis (PSA) and zeta potential confirmed the spherical shape and size (32–200 nm) of silver nanoparticles alongwith stability. Toxicity studies carried out against non-target fish species Poecilia reticulata, the most common organism in the habitats of A. aegypti and A. stephensi showed no toxicity at LC₅₀ and LC₉₀ doses of the AgNPs. This is the first report on mosquito larvicidal activity of latex synthesized nanoparticles.     

Effect of bioactive fractions of <Emphasis Type="Italic">Citrullus vulgaris</Emphasis> Schrad. leaf extract against <Emphasis Type="Italic">Anopheles stephensi</Emphasis> and <Emphasis Type="Italic">Aedes aegypti</Emphasis>

The benzene extract of Citrullus vulgaris was tested against Anopheles stephensi and Aedes aegypti for the larvicidal activity and ovicidal properties. The crude benzene extract was found to be more effective against A. stephensi than A. aegypti. The LC₅₀ values were 18.56 and 42.76 ppm respectively. The LC₅₀ values for silica gel fractions (bioactive fractions I, II, III and IV) were 11.32, 14.12, 14.53 and 16.02 ppm respectively. The mean per cent hatchability of the egg rafts were observed after 48 h post treatment. The crude extract of benzene exerted 100% mortality at 250 ppm against A. stephensi and at 300 ppm against A. aegypti. The silica gel fractions I and II afforded 100% mortality at 100 ppm and III and IV exerted the hatchability rate of 4.9 and 5.3% at the same concentration against A. stephensi.     

Effect of <Emphasis Type="Italic">Myracrodruon urundeuva</Emphasis> leaf lectin on survival and digestive enzymes of <Emphasis Type="Italic">Aedes aegypti</Emphasis> larvae

Aedes aegypti transmits the viruses that cause yellow and dengue fevers. Vector control is essential, since a vaccine for dengue has not as yet been made available. This work reports on the larvicidal activity of Myracrodruon urundeuva leaf lectin (MuLL) against A. aegypti fourth-stage larvae (L₄). Also, the resistance of MuLL to digestion by L₄ gut proteases and the effects of MuLL on protease, trypsin-like and α-amylase activities from L₄ gut were evaluated to determine if lectin remains active in A. aegypti gut and if insect enzyme activities can be modulated by MuLL. MuLL promoted mortality of L₄ with LC₅₀ of 0.202 mg/ml. Haemagglutinating activity of MuLL was detected even after incubation for 96 h with L₄ gut preparation containing protease activity. MuLL affected the activity of gut enzymes, inhibiting protease and trypsin activities and stimulating α-amylase activity. The results suggest that MuLL may become a new biodegradable larvicidal agent for dengue control. Larvicidal activity of MuLL may be linked to its resistance to proteolysis by larval enzymes and interference in the activity of digestive larval enzymes.     

Differential larvicidal efficacy of four species of <Emphasis Type="Italic">Vitex</Emphasis> against <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> larvae

The early fourth instar larvae of Culex quinquefasciatus, reared in the laboratory were used for larvicidal assay with leaf extracts of Vitex negundo, Vitex trifolia, Vitex peduncularis and Vitex altissima. The methanol extracts of the four species possessed varying levels of larvicidal nature. The highest larvicidal activity was found with the extract of V. trifolia (LC₅₀ = 41.41 ppm) followed by V. peduncularis (LC₅₀ = 76.28 ppm), V. altissima (LC₅₀ = 128.04 ppm) and V. negundo (LC₅₀ = 212.57 ppm).     

Efficacy of the <Emphasis Type="Italic">Trichophyton ajelloi</Emphasis> and <Emphasis Type="Italic">Lagenidium giganteum</Emphasis> metabolites against mosquitoes after flash chromatography

Entomopathogens are significant natural enemies for mosquitoes. We have investigated the adulticidal efficacies of metabolites of Trichophyton ajelloi and Lagenidium giganteum against Culex quinquefasciatus and Aedes aegypti simultaneously. The T. ajelloi was grown on Sabouraud’s dextrose broth medium at 25 ± 2°C and relative humidity at 75 ± 5% for 15 days. L. giganteum was grown in peptone yeast extract glucose broth at 25 ± 2°C and relative humidity 75 ± 5% for 15 days. The filtrations of metabolites have been made by using Whatman-1 filter paper then with the flash chromatograph. The bioassays were conducted as per the World Health Organization’s methods and protocols (2006). In this significant investigations, the metabolites of T. ajelloi have been found highly susceptible against A. aegypti with LC₉₉-7.24 ml after an exposure time of 24 h with a comparison, the LC₉₉-66 ml was observed against C. quinquefasciatus after exposure of 24 h. Moreover, the L. giganteum metabolites have shown higher pathogenicity against C. quinquefasciatus with LC₉₉-11.3 ml and A. aegypti with LC₉₉-15.49 ml. Although, the efficacy in adults could be achieved with higher concentration can be significant also. Their adulticidal activities in different climatic zones are plausible with metabolites which have better LT values of T. ajelloi.     

Larvicidal activity of micronized aqueous suspension of calcium hydroxide against <Emphasis Type="Italic">Aedes aegypti</Emphasis> and <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> (Diptera: Culicidae)

In the search of alternatives for the control of mosquitoes of medical importance, we evaluated the larvicidal activity of micronized suspensions of calcium hydroxide [Ca(OH)₂] against Aedes aegypti and Culex quinquefasciatus. Tests conducted under laboratory conditions determined a LC50 = 0.027% (LC90 = 0.096%) for A. aegypti and a LC50 = 0.092% (LC90 = 0.2%) for C. quinquefasciatus, at 24 h post-treatment. Considering that the LC50 for the less susceptible species killed 100% of larvae for both species at 48 h post-treatment, we decided to use the diagnostic concentration of 0.1% which eliminated 100% of larvae at 48 h under a simulated field trial. There was a residual effect for up to 84 and 70 days for A. aegypti and C. quinquefasciatus, respectively. Evaluation of Ca(OH)₂ on breeding sites showed a larvicidal activity of 100% for up to 56 days. When the micronized Ca(OH)₂ was incorporated at concentrations from 0.02% (w/v), a superficial film was formed which killed 100% of the larvae of both species after 24 h of contact, and the activity remains until the film broke apart due to stirring. The fact that Ca(OH)₂ is cheap and the people in rural areas of Mexico and other countries know the handling procedures for this compound led us to consider that 0.1% suspensions of Ca(OH)₂ could be used for mosquito control in deposits of water placed in human premises both in urban and rural areas.     

Efficacy of fungus mediated silver and gold nanoparticles against <Emphasis Type="Italic">Aedes aegypti</Emphasis> larvae

Chrysosporium tropicum is a pathogenic fungus. It is known to be an effective mosquito control agent. In the present study, we have synthesized the silver and gold nanoparticles using C. tropicum. These nanoparticles have been characterized through Microscan reader, X-ray diffractometer, transmission electron microscopy, and further confirmed by scanning electron microscopy. The characterization study confirmed the spherical shape and size (2–15 and 20–50 nm) of gold and silver nanoparticles. These silver and gold nanoparticles have been tested as a larvicide against the Aedes aegypti larvae. The larvicidal efficacy was noted when performed against all instars of A. aegypti at six different log concentrations, and significant results could be observed. The gold nanoparticles used as an efficacy enhancer have shown mortality at three times higher concentration than the silver nanoparticles. The larval mortality was observed after different time of exposures. The mortality values were obtained using the probit analysis. The larvae of A. aegypti were found to be highly susceptible for the silver nanoparticles. The second instar larvae have shown 100% mortality against the silver nanoparticles after 1 h, whereas the first, third, and fourth instars have shown efficacy (LC₅₀ = 3.47, 4, and 2; LC₉₀ = 12.30, 8.91, and 4; LC₉₉ = 13.18, 13.18, and 7.58, respectively) after 1 h. The results could suggest that the use of fungus C. tropicum, silver, and gold nanoparticles is a rapid, environmentally safer, and greener approach for mosquito control. This could lead us to a new possibility in vector control strategy.     

Electroantennogram,flight orientation,and oviposition responses of <Emphasis Type="Italic">Aedes aegypti</Emphasis> to the oviposition pheromone <Emphasis Type="Italic">n</Emphasis>-heneicosane

Oviposition pheromones specifically influence the females of many insects to lay eggs in the sites resulting in more egg deposition. A previous report describes the principal role of n-heneicosane (C₂₁) identified and characterized from the larval cuticle of Aedes aegypti (L.) in attracting the gravid mosquitoes to oviposit in treated substrates among other chemical components. However, the means by which this compound is perceived by the females for oviposition has not been reported. In this study, we have recorded the peripheral olfactory responses from the antenna of Ae. aegypti from 10⁻⁷ g to 10⁻³ g doses of n-heneicosane. The EAG response of female mosquitoes increased in a dose-dependent manner with increasing stimulus strength. In the orientation assay using Y-maze olfactometer, female mosquitoes were attracted to the odor plume of 10⁻⁶ g and 10⁻⁵ g dose, while the higher dose of 10⁻³ g plume enforced repellency to gravid mosquitoes. The response to oviposition substrates by gravid Ae. aegypti females differed across the range of concentrations of n-heneicosane under multiple choice conditions, larger number of eggs were deposited in 10 ppm (10 mg/l) solutions compared to lower and higher concentrations indicating 10 ppm was most attractive. Application of n-heneicosane at 10 ppm in breeding habitats will be a useful method to attract the gravid mosquitoes using ovitraps for surveillance and monitoring. The possible use of this compound in monitoring of mosquito population in endemic areas in relevance to integrated vector management strategies is discussed in detail.     

Laboratory study on larvicidal activity of indigenous plant extracts against <Emphasis Type="Italic">Anopheles subpictus</Emphasis> and <Emphasis Type="Italic">Culex tritaeniorhynchus</Emphasis>

Anopheles subpictus and Culex tritaeniorhynchus have developed resistance to various synthetic insecticides, making its control increasingly difficult. Insecticides of botanical origin may serve as suitable alternative biocontrol techniques in the future. The leaf acetone, chloroform, ethyl acetate, hexane, and methanol extracts of Aegle marmelos (Linn.) Correa ex Roxb, Andrographis lineata Wallich ex Nees., Andrographis paniculata (Burm.f.) Wall. ex Nees., Cocculus hirsutus (L.) Diels, Eclipta prostrata L., and Tagetes erecta L. were tested against fourth-instar larvae of malaria vector, A. subpictus Grassi and Japanese encephalitis vector, C. tritaeniorhynchus Giles (Diptera: Culicidae). All plant extracts showed moderate larvicidal effects after 24 h of exposure at 1,000 ppm; however, the highest larval mortality was found in leaf ethyl acetate of A. marmelos, E. prostrata, hexane, methanol of A. paniculata and C. hirsutus against the larvae of A. subpictus (LC₅₀ = 167.00, 78.28, 67.24, 142.83 ppm; LC₉₀ = 588.31, 360.75, 371.91, and 830.01 ppm) and against the larvae of C. tritaeniorhynchus (LC₅₀ = 99.03, 119.89, 88.50, 105.19 ppm; LC₉₀ = 479.23, 564.85, 416.39, and 507.86 ppm), respectively. These results suggest that the leaf hexane extract of A. paniculata and ethyl acetate extract of E. prostrata have the potential to be used as an ideal eco-friendly approach for the control of the A. subpictus and C. tritaeniorhynchus. Therefore, this study provides first report on the mosquito larvicidal activity of plant extracts against vectors from Southern India.     

Larvicidal activity of <Emphasis Type="Italic">Saraca indica,Nyctanthes arbor-tristis</Emphasis>, and <Emphasis Type="Italic">Clitoria ternatea</Emphasis> extracts against three mosquito vector species

Screening of natural products for mosquito larvicidal activity against three major mosquito vectors Aedes aegypti, Culex quinquefasciatus, and Anopheles stephensi resulted in the identification of three potential plant extracts viz., Saraca indica/asoca, Nyctanthes arbor-tristis, and Clitoria ternatea for mosquito larval control. In the case of S. indica/asoca, the petroleum ether extract of the leaves and the chloroform extract of the bark were effective against the larvae of C. quinquefasciatus with respective LC₅₀ values 228.9 and 291.5 ppm. The LC₅₀ values of chloroform extract of N. arbor-tristis leaves were 303.2, 518.2, and 420.2 ppm against A. aegypti, A. stephensi, and C. quinquefasciatus, respectively. The methanol and chloroform extracts of flowers of N. arbor-tristis showed larvicidal activity against larvae of A. stephensi with the respective LC₅₀ values of 244.4 and 747.7 ppm. Among the methanol extracts of C. ternatea leaves, roots, flowers, and seeds, the seed extract was effective against the larvae of all the three species with LC₅₀ values 65.2, 154.5, and 54.4 ppm, respectively, for A. stephensi, A. aegypti, and C. quinquefasciatus. Among the three plant species studied for mosquito larvicidal activity, C. ternatea was showing the most promising mosquito larvicidal activity. The phytochemical analysis of the promising methanolic extract of the seed extract was positive for carbohydrates, saponins, terpenoids, tannins, and proteins. In conclusion, bioassay-guided fractionation of effective extracts may result in identification of a useful molecule for the control of mosquito vectors.     

Evaluation of larvicidal and nymphicidal potential of plant extracts against <Emphasis Type="Italic">Anopheles subpictus</Emphasis> Grassi, <Emphasis Type="Italic">Culex tritaeniorhynchus</Emphasis> Giles and <Emphasis Type="Italic">Aphis gossypii</Emphasis> Glover

The acetone, chloroform, ethyl acetate, hexane and methanol extracts of peel and leaf extracts of Citrus sinensis, Ocimum canum, Ocimum sanctum and Rhinacanthus nasutus were tested against fourth instar larvae of malaria vector, Anopheles subpictus Grassi, Japanese encephalitis vector, Culex tritaeniorhynchus Giles (Diptera: Culicidae) and feeding deterrence to nymphs of cotton pest, Aphis gossypii Glover (Homoptera: Aphididae). The larval and nymph mortality were observed after 24 h of exposure. All extracts showed moderate larvicidal and nymphicidal effects; however, the highest mortality was found in peel chloroform extract of C. sinensis, leaf ethyl acetate extracts of O. canum and O. sanctum and leaf chloroform extract of R. nasutus against the larvae of A. subpictus (LC₅₀ = 58.25, 88.15, 21.67 and 40.46 ppm; LC₉₀ = 298.31, 528.70, 98.34 and 267.20 ppm), peel methanol extract of C. sinensis, leaf methanol extract of O. canum, ethyl acetate extracts of O. sanctum and R. nasutus against the larvae of C. tritaeniorhynchus (LC₅₀ = 38.15, 72.40, 109.12 and 39.32 ppm; LC₉₀ = 184.67, 268.93, 646.62 and 176.39 ppm), peel hexane extract of C. sinensis, leaf methanol extracts of O. canum and R. nasutus and leaf ethyl acetate extract of O. sanctum against the nymph of A. gossypii (LC₅₀ = 162.89, 80.99, 73.27 and 130.19 ppm; LC₉₀ = 595.40, 293.33, 338.74 and 450.90 ppm), respectively. These results suggest that the peel methanol extracts of C. sinensis and O. canum, ethyl acetate leaf extract of O. sanctum and leaf chloroform and ethyl acetate extract of R. nasutus have the potential to be used as an ideal eco-friendly approach for the control of the A. subpictus, C. tritaeniorhynchus and A. gossypii.     

Evaluation of indigenous plant extracts against larvae of <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> Say (Diptera: Culicidae)

This study investigates the larvicidal potential of indigenous plant extracts from commonly used medicinal herbs as an environmentally safe measure to control the filarial vector, Culex quinquefasciatus Say (Diptera: Culicidae). The early fourth-instar larvae of C. quinquefasciatus, reared in the laboratory, were used for larvicidal assay with water, hot water, acetone, chloroform, and methanol leaf, stem-bark, and flower extracts of Acacia arabica Willd. Sans, Cedrus deodara Roxb, Hibiscus rosa-sinensis L., Mangifera indica L., Nerium indicum Mill., Nicotiana tabacum Linn., Pongamia pinnata (L.) Pierre, and Solanum nigrum Linn. All plant extracts showed moderate larvicidal effects after 24 h of exposure at 1,000 ppm; however, the highest larval mortality was found in stem-bark hot water, acetone, and methanol extracts of C. deodara (LC₅₀ = 133.85, 141.60, and 95.19 ppm, LC₉₀ = 583.14, 624.19, and 639.99 ppm) and leaf hot water, acetone, methanol, and chloroform extracts of N. tabacum (LC₅₀ = 76.27, 163.81, 83.38, and 105.85 ppm, LC₉₀ = 334.72, 627.38, 709.51, and 524.39 ppm) against the larvae of C. quinquefasciatus, respectively. This is an ideal ecofriendly approach for the control of lymphatic filariasis vector, C. quinquefasciatus.     

Anthelmintic effect of a methanol extract of <Emphasis Type="Italic">Bombax malabaricum</Emphasis> leaves on <Emphasis Type="Italic">Paramphistomum explanatum</Emphasis>

Bombax malabaricum (family Bombacaceae) is used as anthelmintic in traditional system of medicine in Southern Punjab of Pakistan. The objective of this study was to evaluate the anthelmintic activity of the methanol extract of B. malabaricum leaves (MEBM). Live parasites (trematode: Paramphistomum explanatum) were collected from buffalo in 0.9% phosphate-buffered saline. It was incubated in Petri dishes at 37 ± 1°C in media containing either no extract (control) or MEBM, the test drug at 10, 25, 50, and 100 mg/ml dose level or albendazole, the standard drug at 10 mg/ml. The efficacy of the extract or albendazole was measured on the basis of the loss of spontaneous movement and/or death of the trematodes. Paralysis was considered when there is no movement unless shaken vigorously. Death was confirmed when the trematodes completely lost their motility, even when vigorously shaken or dipped in warm water (50°C), followed by fading away of their body color. The trematodes, both drug treated and others, were further processed for SEM study using the standard method. All trematodes died with all the above-mentioned doses of MEBM within a short period of time (less than 45 min) which was statistically highly significant (p < 0.001). MEBM at 100 mg/ml showed maximum efficacy. It paralyzed and killed trematodes in 18.50 ± 0.62 and 22.17 ± 0.48 min, respectively. SEM study showed that MEBM-treated trematodes were stretched. The study established the anthelmintic activity of MEBM.     

Efficacy of larvicidal botanical extracts against <Emphasis Type="Italic">Culex quinquefasciatus</Emphasis> Say (Diptera: Culicidae)

The present study explored the effects of crude leaf acetone, chloroform, hot water, methanol, petroleum ether (60–80°C), and water extracts of Calotropis procera (Ait) R. Br., Canna indica L., Hibiscus rosa-sinensis Linn., Ipomoea carnea Jacq. spp. fistulosa Choisy, and Sarcostemma brevistigma Wight that were selected for investigating larvicidal potential against second and fourth instar larvae of the laboratory-reared mosquito species, Culex quinquefasciatus Say, in which the major lymphatic filariasis was used. All plant extracts showed moderate larvicidal effects after 24 h of exposure at 1,000 ppm; however, the highest larval mortality was found in leaf acetone, chloroform, methanol, and petroleum ether of C. indica (LC₅₀ = 29.62, 59.18, 40.77, and 44.38 ppm; LC₉₀ = 148.55, 267.87, 165.00, and 171.91 ppm) against second instar larvae (LC₅₀ = 121.88, 118.25, 69.76, and 56.31 ppm; LC₉₀ = 624.35, 573.93, 304.27, and 248.24 ppm) and against fourth instar larvae and acetone, hot water, methanol, and petroleum ether extracts of I. carnea (LC₅₀ = 61.17, 41.07, 41.82, and 39.32 ppm; LC₉₀ = 252.91, 142.67, 423.76, and 176.39 ppm) against second instar larvae (LC₅₀ = 145.37, 58.00, 163.81, and 41.75 ppm; LC₉₀ = 573.30, 181.10, 627.38, and 162.63 ppm) and against fourth instar larvae of C. quinquefasciatus, respectively. These results suggest that the acetone, methanol extracts of C. indica and hot water, petroleum ether extracts of I. carnea have the potential to be used as an ideal eco-friendly approach for the control of the major lymphatic filariasis vector, C. quinquefasciatus.     

Larvicidal efficacy of <Emphasis Type="Italic">Jatropha curcas</Emphasis> and bacterial insecticide, <Emphasis Type="Italic">Bacillus thuringiensis</Emphasis>, against lymphatic filarial vector<Emphasis Type="Italic">, Culex quinquefasciatus</Emphasis> Say (Diptera: Culicidae)

The present study explored the effects of Jatropha curcas leaf extract and Bacillus thuringiensis israelensis larvicidal activity against the lymphatic filarial vector, Culex quinquefasciatus. Wights were selected for investigating the larvicidal potential against the first to fourth instar larvae of the laboratory-reared mosquito species, C. quinquefasciatus Say, in which the major lymphatic filariasis was used. The medicinal plants were collected from the area around Bharathiar University, Coimbatore. The dried plant materials were powdered by an electric blender. From the powder, 100 g of the plant materials was extracted with 300 ml of organic solvents of methanol for 8 h, using a Soxhlet apparatus, and filtered. The crude plant extracts were evaporated to dryness in a rotary vacuum evaporator. The plant extract showed larvicidal effects after 24 h of exposure; however, the highest larval mortality was found in the leaf extract of methanol J. curcas against the first to fourth instar larvae of values LC₅₀ = 1.200%, 1.290%, 1.358%, and 1.448% and LC₉₀ = 2.094%, 2.323%, 2.444%, and 2.544% and B. thuringiensis israelensis against the first to fourth instar larvae of values LC₅₀ = 9.332%, 9.832%, 10.212%, 10.622% and LC₉₀ = 15.225%, 15.508%, 15.887%, and 15.986% larvae of C. quinquefasciatus, respectively. No mortality was observed in the control. These results suggest methanol extracts of J. curcas and B. thuringiensis israelensis have potential to be used as an ideal eco-friendly approach for the control of the major lymphatic filarial vector, C. quinquefasciatus.     

Efficacy of <Emphasis Type="Italic">Lagenidium giganteum</Emphasis> metabolites on mosquito larvae with reference to nontarget organisms

Lagenidium giganteum is a water mold and an effective mosquito control agent with limited use due to poor survival and contamination during storage. Invert extracellular metabolites of L. giganteum is easy to produce, long shelf life, and a potential candidate in tropical climates. This fungus was grown in PYG broth in the laboratory at 25 ± 2°C, and relative humidity was maintained at 75 ± 5% for 15 ± 2 days. Filtration process of metabolites was done using Whatman filter paper, column chromatograph, and range syringe filters techniques. Then 5-ml fractions were collected and used to assay larvicidal efficacies. Larvicidal efficacies were performed against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti at five different concentrations, viz. 1.68, 1.99, 2.17, 2.30, and 2.40 ppm. And also, filtrates were assessed against four species of nontarget organisms named Daphnia pulex, Cyclopes, Lymnea auriculeta, and tadpoles of Rana tigrina with different concentrations. The mortality values were subjected by the Probit analysis. The complete mortalities that resulted from applying filtrates dosage on all instars of mosquitoes persisted for a period of 24, 48, and 72 h, respectively. The efficacies in killing instar of three important vectors and safer for nontarget organisms with good biological stability of extracellular metabolites make this a promising alternative to mycelium and conidial-based larvicides. It could be regarded as fungal-based natural larvicide for the use of vector control.     

<Emphasis Type="Italic">Myxobolus honghuensis</Emphasis> n. sp. (Myxosporea: Bivalvulida) parasitizing the pharynx of allogynogenetic gibel carp <Emphasis Type="Italic">Carassius auratus gibelio</Emphasis> (Bloch) from Honghu Lake,China

Myxobolus honghuensis n. sp. is described from allogynogenetic gibel carp Carassius auratus gibelio (Bloch), during a survey of myxosporean parasites in Honghu Lake, Hubei Province, China. It is characterized by the presence of round plasmodia of 5–12 mm in diameter in the pharynx of host. Mature spores of M. honghuensis were pyriform in frontal view and anterior pointed with bluntly round posterior, they measured 16.9 ± 0.5 (15.1–19.5) μm long, 10.4 ± 0.4 (9.0–11.3) μm wide, and 8.4 ± 0.4 (7.9–9.1) μm thick. Two polar capsules were pyriform and slightly unequal with larger polar capsule 8.4 ± 0.4 (7.6–10.2) μm × 3.9 ± 0.2 (3.0–4.5) μm and smaller capsule 7.9 ± 0.2 (7.0–9.3) μm × 3.7 ± 0.3 (2.8–4.1) μm. Polar filaments coiled with seven to eight turns. Both morphology and DNA sequence data revealed that M. honghuensis n. sp. was distinct from other described Myxobolus species. Phylogenetic analysis placed M. honghuensis n. sp. in a clade of gill-infecting myxobolids.     

<Emphasis Type="Italic">Eimeria biarmicus</Emphasis> sp.n. (Apicomplexa: Eimeriidae) infecting falcons from the genus <Emphasis Type="Italic">Falco</Emphasis> in Saudi Arabia

The oocysts of Eimeria biarmicus sp. n. were described from the feces of the lanner falcon, Falco biarmicus, collected from the falcon market in Riyadh City, Saudi Arabia. The prevalence of infection was 5% (2/40). The majority of the oocysts examined had completed sporulation within 84 h at 24 ± 2°C. Sporulated oocysts are ovoid in shape, measuring 22.4 × 17.9 (20.5–24.7 × 15.8–18.5) μm; shape index (L/W) is 1.25 (1.14–1.36) μm. The oocyst wall is smooth and bi-layered. Micropyle and oocyst residuum are absent. A polar granule is present, consisting of 2–4 globules. Sporocysts are ovoid, 10.1 × 6.1 (9.4–11.2 × 5.4–6.8) μm; with a smooth single-layered wall and a minute Stieda body, but there is no substieda body. The sporocyst residuum consists of numerous small granules. Sporozoites are comma shaped, each contains two refractile bodies. E. biarmicus sp. n. is the second eimerian species described from F. biarmicus.     

Cloning,expression, and characterization of salivary apyrase from <Emphasis Type="Italic">Aedes albopictus</Emphasis>

Apyrases (ATP diphosphohydrolase) hydrolyze the phosphodiester bonds of nucleoside tri- and diphosphates to orthophosphate and mononucleodides. They can inhibit platelet activation by depletion of adenosine diphosphate. In the current study, the Escherichia coli expression vector pET-19b equipped with an N-terminal histidine tag was applied to express the apyrase of Aedes albopictus. The gene-coding mature apyrase protein was amplified by RT-PCR and cloned into pET-19b. Soluble apyrase protein with high purity was successfully obtained by utilization of the suitable renaturation approach and Ni-NTA purification column. Four monoclonal antibodies to apyrase from A. albopictus were produced in male BALB/c mice immunized with the renatured apyrase. Using immunofluorescence assay and immunoblotting analysis, recombinant apyrase showed fine consistency with native apyrase. From kinetic analysis, it had a K _m of 11.6 μM and V _max of 1.02 nM/S/μg protein for adenosine triphosphate. Adenosine diphosphate-induced platelet aggregation was inhibited by approximately 6% when 0.4 μM recombinant apyrase was added and by about 9.5% when the concentration of recombinant apyrase was 0.8 μM. The effect on platelet aggregation was dose dependent. In conclusion, the apyrase of A. albopictus was cloned and expressed highly in the E. coli expression system. Recombinant apyrase protein showed biological activity, and anti-apyrase monoclonal antibody was also prepared.