Possible fasciocidal activity of methanol extract of Dregea volubilis leaves

In eastern and southern part of India Dregea volubilis (Family Asclepediaceae) is widely used as anthelmintic in traditional system of medicine. The present study was conducted to evaluate the fasciocidal activity of the methanol extract of D. volubilis leaves (MEDV) and to observe the drug’s effect on organisms through scanning electron microscopic (SEM) study. Live parasites (Trematode: Fasciola gigantica) were collected in 0.9% phosphate-buffered saline from the bile ducts of buffalo. Those were incubated in the said media at 37 ± 1 °C either as control, or with MEDV at 5, 10, 25, 50 and 100 mg/ml as test groups or with albendazole at 10 mg/ml as standard group. The efficacy of the extract was determined on the basis of paralysis (temporary loss of spontaneous movement of the organisms) and/or death of the liver flukes. Death was confirmed when the organisms lost their motility permanently and their motility could not be revived even when vigorously shaken or dipped in warm water. MEDV at all concentration effectively paralyzed first and then killed the liver flukes (p < 0.001). Maximum fasciocidal activity was found with concentration of 100 mg/ml at 38.83 ± 3.41 min. Through SEM study, severe damages were observed in both the suckers as well as on the tegumental surfaces of the treated liver flukes. The study confirmed the fasciocidal activity of the MEDV.     

Fasciolagigantica: Parasitological and scanning electron microscopy study of the in vitro effects of ivermectin and/or artemether

Objective

To evaluate the in vitro effects of different concentrations of ivermectin and/or artemether on Fasciolagigantica worms and to study the parasitological changes and tegumental alterations using scanning electron microscopy (SEM).

Methods

Fasciola gigantica worms were incubated in vitro for 24 and 48 h with three concentrations of either ivermectin or artemether (10, 20 and 50 μg/ml) or both in half concentration of either (5, 10 and 25 μg/ml).

Results

Exposure of Fasciola worms to 25 + 25 μg/ml of combined drug regimens or to 50 μg/ml of either ivermectin or artemether for 48 h led to 100%, 41.7% and 75% worm killing which were accompanied by a significant reduction in egg laying capacity and significant increase in dead eggs maximally recorded in combined drug regimens. SEM of the flukes incubated for 48 h with combined drug regimens showed maximal tegumental disruption with swelling of the worm body, roughness, blebbing, sloughing and complete loss of spines. Disruption to the tegument of the flukes induced by artemether was more than that of ivermectin.

Conclusions

Artemether alone or combined with ivermectin in half doses had potent fasciocidal activities. Besides, half doses of combined drug regimens had higher ovicidal effects than each drug alone. In vivo studies are recommended to explore the efficacy of combined regimens against Fasciola infection.     

Genotypic characterization and species identification of Fasciola spp. with implications regarding the isolates infecting goats in Vietnam

Ribosomal RNA sequences (361 or 362 bp) of the second internal transcribed spacer 2 (ITS-2) and a portion of mitochondrial cox1 (423 bp) for Fasciola spp. obtained from specimens collected in indigenous and hybrid goats and sheep in Vietnam were characterized for genotypic status and hybridization/introgression. Alignment of 48 ITS-2 sequences (also those from goats and sheep in this study) indicates that F. gigantica and F. hepatica differ typically from each other at seven sites whereas one of these is a distinguishing deletion (T) at the 327th position in F. gigantica relative to F. hepatica. The isolates from the mountainous goats in the North of Vietnam (Yen Bai province) showed the ITS-2 composition relatively identical to that of F. hepatica. The ITS-2 sequences from populations of Fasciola isolates in goats had probably experienced introgression/hybridization as reported previously in other ruminants and humans. All Vietnamese goat-of-origin specimens had high pairwise percentage of mitochondrial cox1 sequences to F. gigantica (97-100%), and very low identity to F. hepatica (91-93%), suggesting their maternal linkage to be traced to F. gigantica. The presence of hybrid and/or introgressed populations of liver flukes bearing genetic material from both F. hepatica and F. gigantica in the goats/sheep in Vietnam, regardless of indigenous or imported hosts, appears to be the first demonstration from a tropical country.     

Nematicidal activity of Haplophyllum tuberculatum and Plectranthus cylindraceus oils against Meloidogyne javanica

The potentials of Haplophyllum tuberculatum and Plectranthus cylindraceus oils to control Meloidogyne javanica were investigated in vitro and in a greenhouse. A mixture of Haplophyllum and Plectranthus oils (1:1) was highly toxic to M. javanica in vitro, as it killed all nematode juveniles and inhibited hatching of eggs at 12.5 μg/ml concentration after 24 h exposure time, as did carbofuran at the same concentration. In the green-house, tomatoes grown in soil treated with a combination (1:1) of the two oils developed fewer root galls than those grown in soil treated with higher doses of either oil. The oil mixture, at 2.5 and 5.0 μg/ml of soil, was not phytotoxic to tomato plants as evident from the appearance and height of plants after 12 weeks exposure time, compared to treatment over the same period at lower effective doses. The nematicidal activity of the combined essential oils was suggested by the presence of C₁₀ dienes, C₁₀ trienes and C₁₀ phenol.     

Chemical composition and larvicidal activity of essential oils from Piper species

The larvicidal activity of essential oils of four species of Piper from the Amazon Forest was tested using third-instar larvae of Aedes aegypti. The oils were extracted by steam distillation and analyzed by GC and GC–MS. The main components isolated from each Piper species were as follows: viridiflorol (27.50%), aromadendrene (15.55%) and β-selinene (10.50%) from Piper gaudichaudianum; β-selinene (15.77%) and caryophyllene oxide (16.63%) from Piper humaytanum; dillapiol (54.70%) and myristicin (25.61%) from Piper permucronatum; and asaricin (27.37%) and myristicin (20.26%) from Piper hostmanianum. Amongst all essential oils tested, the most active against larvae of A. aegypti was the oil extracted from P. permucronatum, with a LC₅₀ = 36 μg/ml (LC₉₀ = 47 μg/ml), followed by the essential oil of P. hostmanianum, with a LC₅₀ = 54 μg/ml (LC₉₀ = 72 μg/ml). The oils with higher content of arylpropanoids were more active against larvae of A. aegypti.     

Fasciola gigantica: Immunodiagnosis of fasciolosis by detection of circulating 28.5 kDa tegumental antigen

A monoclonal antibody (MoAb)-based sandwich ELISA was developed for the detection of circulating 28.5 kDa tegumental antigen (28.5 kDa TA) in the sera from mice experimentally infected with Fasciola gigantica. The MoAb was immobilized on a microtiter plate, and the antigen in the serum was captured and detected with biotinylated polyclonal rabbit anti TA antibody. The test could detect 28.5 kDa in the extracts of tegument (TA), whole body (WB) and excretory-secretory (ES) fractions at the concentrations of these crude antigens as low as 600 pg/ml, 16 and 60 ng/ml, respectively. This sandwich ELISA assay could detect the infection from day 1 to 35 post infection and showed that circulating level of 28.5 kDa TA peaked at day 1 post infection. In contrast, the antibody detection by indirect ELISA could only demonstrate the antibody level from 35 days post infection. The reliability of the assay method was evaluated using sera from mice infected with F. gigantica or Schistosoma mansoni, and hamsters infected with Opisthorchis viverrini, as well as healthy mice and hamsters. The sandwich ELISA exhibited a sensitivity and specificity at 94.55% and 100%, respectively, and with a positive predictive value of 100%, a negative predictive value of 97.39%, false positive rate of 0%, false negative rate of 5.50% and an accuracy of 98.2%. Thus, this detection method exhibited high specificity and sensitivity as well as could be used for early diagnosis of fasciolosis by F. gigantica.     

Cardiodepressive effect elicited by the essential oil of Alpinia speciosa is related to L-type Ca current blockade

This study was undertaken to elucidate the effect of the essential oil from Alpinia speciosa (EOAs) on cardiac contractility and the underlying mechanisms. The essential oil was obtained from Alpinia speciosa leaves and flowers and the oil was analyzed by GC-MS method. Chemical analysis revealed the presence of at least 18 components. Terpinen-4-ol and 1,8-cineole corresponded to 38% and 18% of the crude oil, respectively. The experiments were conducted on spontaneously-beating right atria and on electrically stimulated left atria isolated from adult rats. The effect of EOAs on the isometric contractions and cardiac frequency in vitro was examined. EOAs decreased rat left atrial force of contraction with an EC₅₀ of 292.2 ± 75.7 μg/ml. Nifedipine, a well known L-type Ca²⁺ blocker, inhibited in a concentration-dependent manner left atrial force of contraction with an EC₅₀ of 12.1 ± 3.5 μg/ml. Sinus rhythm was diminished by EOAs with an EC₅₀ of 595.4 ± 56.2 μg/ml. Whole-cell L-type Ca²⁺ currents were recorded by using the patch-clamp technique. EOAs at 25 μg/ml decreased I_Ca,L by 32.6 ± 9.2% and at 250 μg/ml it decreased by 89.3 ± 7.4%. Thus, inhibition of L-type Ca²⁺ channels is involved in the cardiodepressive effect elicited by the essential oil of Alpinia speciosa in rat heart.     

Identification and differentiation of Fasciola hepatica and Fasciola gigantica using a simple PCR-restriction enzyme method

Accurate morphological differentiation between the liver fluke species Fasciola hepatica and Fasciola gigantica is difficult. We evaluated PCR-restriction enzyme profiles of internal transcribed spacer 1 (ITS1) that could aid in their identification. Fifty F. hepatica and 30 F. gigantica specimens were collected from different hosts in three provinces of Iran. For DNA extraction, we crushed fragments of the worms between two glass slides as a new method to break down the cells. DNA from the crushed materials was then extracted with a conventional phenol-chloroform method and with the newly developed technique, commercial FTA cards. A primer pair was selected to amplify a 463-bp region of the ITS1 sequence. After sequencing 14 samples and in silico analysis, cutting sites of all known enzymes were predicted and TasI was selected as the enzyme that yielded the most informative profile. Crushing produced enough DNA for PCR amplification with both the phenol-chloroform and commercial FTA card method. The DNA extracted from all samples was successfully amplified and yielded a single sharp band of the expected size. Digestion of PCR products with TasI allowed us to distinguish the two species. In all samples, molecular identification was consistent with morphological identification. Our PCR-restriction enzyme profile is a simple, rapid and reliable method for differentiating F. hepatica and F. gigantica, and can be used for diagnostic and epidemiological purposes.     

Activity of oil-formulated conidia of the fungal entomopathogens Nomuraea rileyi and Isaria tenuipes against lepidopterous larvae

The fungi Nomuraea rileyi and Isaria tenuipes (=Paecilomyces tenuipes) are ecologically obligate, widespread pathogens of lepidopterans. Bioassays were carried out to evaluate the activity of oil-suspended conidia of N. rileyi and I. tenuipes against larvae of Spodoptera frugiperda, Spodoptera exigua, Helicoverpa zea, and Heliothis virescens. The tests consisted of two bioassay sets. In the first set, conidia of N. rileyi and I. tenuipes were suspended in water + Tween 80, and in vegetable (canola, soybean) and mineral (proprietary mixture of alkanes and cyclic paraffins) oils, and tested against S. frugiperda. Both fungi were highly compatible with oils and caused mortalities near 100% in all oil treatments; the lowest LT₅₀ values were 4.7 days for N. rileyi in mineral oil and 6.0 days for I. tenuipes in soybean oil. The second set included additional fungal strains and oil formulations (mineral, canola, sunflower, olive and peanut oils) tested against larvae of S. exigua, S. frugiperda, H. zea and H. virescens. The highest activity was that of N. rileyi in mineral oil against Spodoptera spp., with LT₅₀ values of 2.5 days (strain ARSEF 135) and 3 days (strain ARSEF 762) respectively. For two different isolates of I. tenuipes the lowest LT₅₀ values (5.1-5.6 days respectively) were obtained with mineral oil formulations against Spodoptera spp. and H. zea respectively. Additionally, we tested both fungi against prepupae of all four lepidopteran species. Mortalities with I. tenuipes against S. exigua ranged from 90% to 100% (strains ARSEF 2488 and 4096); N. rileyi caused 95% mortality on S. frugiperda. The activity of formulations depended on host species and oil used; Spodoptera spp. was more susceptible to these fungi than Heliothis and Helicoverpa. The results indicate that a comprehensive evaluation of these entomopathogens in agriculture using oil application technologies is advisable, particularly, in organic and sustainable settings.     

Involvement of nitric oxide (NO) signalling pathway in the antidepressant activity of essential oil of Valeriana wallichii Patchouli alcohol chemotype

Valeriana wallichii DC (Valerianaceae), popularly named as Indian valerian has been shown to exist as three chemotypes. The present study evaluated the antidepressant like effect of root essential oil of Valeriana wallichii patchouli alcohol chemotype in both acute and chronic treatment study using forced swim test (FST). Mice (n = 6 per group) received 10, 20 and 40 mg/kg p.o. doses of test drug. Single administration of oil significantly inhibited the immobility period (57.6% and 46.9%) at doses 20 and 40 mg/kg respectively without changing the motor function (p < 0.05). Similarly, daily administration of essential oil (20 mg/kg) for 14 days significantly reduced the immobility period (69.9%) in FST (p < 0.05). The neurotransmitter levels in mouse brain were estimated on day 14 after the behavioral study. Significant increase in the level of norepinephrine (29%) and serotonin (19%) (p < 0.05) was found at 20 mg/kg dose, while no change was observed at 10 and 40 mg/kg doses. The antidepressant-like effect of essential oil (20 mg/kg) was prevented by pretreatment of mice with l-arginine (750 mg/kg i.p.) and sildenafil (5 mg/kg i.p). On the contrary, pretreatment of mice with l-NAME (10 mg/kg i.p.) or methylene blue (10 mg/kg i.p.) potentiated the antidepressant action of essential oil (10 mg/kg). Taken together, these findings demonstrated that nitric oxide pathway is involved in mediating antidepressant like effect of essential oil from this chemotype.     

Lavandula angustifolia essential oil as a novel and promising natural candidate for tick (Rhipicephalus (Boophilus) annulatus) control

Lavandula angustifolia is a well known herbal medicine with a variety of useful properties, including its acaricidal effect. This experiment was carried out to study the bioacaricidal activity of L. angustifolia essential oil (EO) against engorged Rhipicephalus (Boophilus) annulatus (Acari; Ixodidae) females. For this purpose six serial concentrations (0.5, 1.0, 2.0, 4.0, 6.0 and 8.0% w/v) of L. angustifolia EO were used. There was considerable mortality in concentrations more than 4.0% although there were no differences between 6.0 and 8.0% in all measured criteria. The mortality rate 24 h after inoculation was 73.26 and 100% in groups treated with 4.0 and 8.0% EO, respectively. Lavender EO also reduced tick egg weight in a concentration-dependent manner. The amount of eggs produced varied from 0.12 g (at 0.5% EO) to 0.00 g (at 8.0% EO) but did not differ statistically from the control. L. angustifolia EO caused 100% failure in egg laying at 6.0 and 8.0% whereas this value in the control group was zero. A positive correlation between L. angustifolia EO concentration and tick control, assessed by relative mortality rate and egg-laying weight, was observed by the EO LC/EC₅₀, which, when calculated using the Probit test, was 2.76-fold higher than the control. Lavender is a promising acaricidal against R. (B.) annulatusin vitro.     

Insecticidal activity and chemical composition of the essential oil of Artemisia vestita from China against Sitophilus zeamais

In our screening program for new agrochemicals from local wild plants, essential oil of Artemisia vestita Wall (Asteraceae) was found to possess strong insecticidal activity against maize weevil, Sitophilus zeamais Motsch. Essential oil of aerial parts of A. vestita was obtained from hydrodistillation and was investigated by GC and GC–MS. The main components of essential oil were grandisol (40.29%), 1,8-cineol (14.88%) and camphor (11.37%). The essential oil of A. vestita possessed strong fumigant toxicity against S. zeamais adults with a LC₅₀ value of 13.42 mg/L air. The essential oil of A. vestita also showed contact toxicity against S. zeamais adults with a LD₅₀ value of 50.62 mg/adult.     

Fasciola gigantica: Cercarial shedding pattern from Lymnaea natalensis after long-term exposure to cadmium at different temperatures

Little is known about the response of Fasciola spp., inside its snail host to pollutant toxicity. The effect of long-term exposure of Lymnaea natalensis to 0.1 μg/l, 10 μg/l, or 100 μg/l cadmium (Cd) on the infection rates with F. gigantica, percentage of cercariae-shedding snails and cercariae shedding pattern was investigated. The snails were exposed to Cd for 7 days either pre-infection with single Fasciola miracidium or during the late pre-patent period of the infection. The possible interaction between metal exposure and acclimatization temperature was also studied in three ranges; 16-18 °C, 23-25 °C and 30-32 °C. Results clearly showed that host exposure to 100 μg/l Cd significantly affected the pattern of Fasciola development inside its snail host, and that the acclimatization temperature was a key factor affecting the role played by Cd. Pre-infection exposure to Cd caused a significant reduction in the infection rates where the effect was temperature-dependent. Post-infection exposure to Cd significantly increased the percentage of cercariae-shedding snails; the effect was temperature-independent. Interestingly, post-infection exposure significantly altered the differential cercarial output pattern, while no clear impact on the total was found. The alteration in the differential cercarial output was represented as a significantly higher proportion of floating metacercaria as compared to fixed ones and also higher proportion of dead cercariae which may directly reduce the transmission of Fasciola to the final host. The mechanisms of cadmium impact are briefly discussed.     

A multicenter pilot external quality assessment programme to assess the quality of molecular detection of Chlamydophila pneumoniae and Mycoplasma pneumoniae

An external quality assessment (EQA) panel consisting of a total of 13 samples in broncho alveolar lavage (BAL) or transport medium was prepared to assess the proficiency of laboratories in the correct detection of Chlamydophila pneumoniae and Mycoplasma pneumoniae by nucleic acid amplification techniques (NAATs) (6 samples containing various concentrations (4.9-490 inclusion forming units (IFU)/ml) of C. pneumoniae, 5 samples containing various concentrations (20-5000 color-changing units (CCU)/ml) of M. pneumoniae and 2 samples negative for both).Seventy-nine laboratories from 18 countries participated in this EQA study. Sixty-four datasets were returned for C. pneumoniae (n = 5 conventional commercial, n = 10 conventional in-house, n = 4 real-time commercial, n = 43 real-time in-house, and n = 2 SDA). Sixty-seven datasets were obtained for M. pneumoniae (n = 5 conventional commercial, n = 10 conventional in-house, n = 4 real-time commercial, n = 46 real-time in-house, and n = 2 strand displacement amplification (SDA)). For the total panels, correct results per sample varied between 95.3% and 100% for C. pneumoniae and between 53.7% and 95.5% for M. pneumoniae. In general, commercial conventional NAATs showed possible sensitivity issues when compared to conventional in-house NAATs for both organisms. On the other hand, real-time commercial NAATs scored better than real-time in-house assays in terms of sensitivity for both organisms. For C. pneumoniae and M. pneumoniae, 0.8% and 2.2% true false-positive results and 1.9% and 2.0% false positives were reported in the samples spiked with the other organism.Analysis of the data for C. pneumoniae showed that the concentrations used were easily detectable by the vast majority of participants. The percentage of correct qualitative results for M. pneumoniae demonstrated that the concentrations included in this panel proved challenging for a number of participants.     

Protective role of Mangifera indica, Cucumis melo and Citrullus vulgaris peel extracts in chemically induced hypothyroidism

An investigation was made to evaluate the pharmacological importance of fruit peel extracts of Mangifera indica (MI), Citrullus vulgaris (CV) and Cucumis melo (CM) with respect to the possible regulation of tissue lipid peroxidation (LPO), thyroid dysfunctions, lipid and glucose metabolism. Pre-standardized doses (200 mg/kg of MI and 100 mg/kg both of CV and CM), based on the maximum inhibition in hepatic LPO, were administered to Wistar albino male rats for 10 consecutive days and the changes in tissue (heart, liver and kidney) LPO and in the concentrations of serum triiodothyronine (T₃), thyroxin (T₄), insulin, glucose, α-amylase and different lipids were examined. Administration of three test peel extracts significantly increased both the thyroid hormones (T₃ and T₄) with a concomitant decrease in tissue LPO, suggesting their thyroid stimulatory and antiperoxidative role. This thyroid stimulatory nature was also exhibited in propylthiouracil (PTU) induced hypothyroid animals. However, only minor influence was observed in serum lipid profile in which CM reduced the concentrations of total cholesterol and low-density lipoprotein-cholesterol (LDL-C), while CV decreased triglycerides and very low-density lipoprotein-cholesterol (VLDL-C). When the combined effects of either two (MI + CV) or three (MI + CV + CM) peel extracts were evaluated in euthyroid animals, serum T₃ concentration was increased in response to MI + CV and MI + CV + CM treatments, while T₄ level was elevated by the combinations of first two peels only. Interestingly, both the categories of combinations increased T₄ levels, but not T₃ in PTU treated hypothyroid animals. Moreover, a parallel increase in hepatic and renal LPO was observed in these animals, suggesting their unsafe nature in combination. In conclusion the three test peel extracts appear to be stimulatory to thyroid functions and inhibitory to tissue LPO but only when treated individually.     

Sulfadoxine-pyrimethamine impairs Plasmodium falciparum gametocyte infectivity and Anopheles mosquito survival

Sulfadoxine-pyrimethamine (SP) is currently the drug of choice for intermittent preventive treatment of Plasmodiumfalciparum both in pregnancy and infancy. A prolonged parasite clearance time conferred by dhfr and dhps mutations is believed to be responsible for increased gametocyte prevalence in SP treated individuals. However, using a direct feeding assay in Mali, we showed that gametocytes present in peripheral venous blood post-SP treatment had reduced infectivity for Anophelesgambiae sensu stricto (ss) mosquitoes. We investigated the potential mechanisms involved in the dhfr and dhps quintuple mutant NF-135 and the single dhps 437 mutant NF-54. Concentrations of sulfadoxine (S) and pyrimethamine (P) equivalent to the serum levels of the respective drugs on day 3 (S = 61 μg/ml, P = 154.7 ng/ml) day 7 (S = 33.8 μg/ml, P = 66.6 ng/ml) and day 14 (S = 14.2 μg/ml, P = 15.7 ng/ml) post-SP treatment were used to study the effect on gametocytogenesis, gametocyte maturation and infectivity to Anophelesstephensi mosquitoes fed through an artificial membrane. The drugs readily induced gametocytogenesis in the mutant NF-135 strain but effectively killed the wild-type NF-54. However, both drugs impaired gametocyte maturation yielding odd-shaped non-exflagellating mature gametocytes. The concomitant ingestion of both S and P together with gametocytemic blood-meal significantly reduced the prevalence of oocyst positivity as well as oocyst density when compared to controls (P < 0.001). In addition, day 3 concentrations of SP decreased mosquito survival by up to 65% (P < 0.001). This study demonstrates that SP is deleterious in vitro for gametocyte infectivity as well as mosquito survival.     

Changes in composition of essential oils and volatile emissions of Minthostachys mollis, induced by leaf punctures of Liriomyza huidobrensis

Plant defensive mechanisms against herbivores include chemical changes following damage. Effects of feeding punctures produced by Liriomyza huidobrensis (pea leafminers) adult females on the plant's dominant monoterpenes, pulegone and menthone were assessed by monitoring essential oil composition at 24, 48, and 120 h; emission of volatiles was also measured 24 and 48 h after wounding. We studied such changes in Minthostachys mollis, a Lamiaceae species native to Central Argentina with medicinal and aromatic uses. Leaf puncturing resulted in reduced menthone throughout the experiment and increased pulegone concentration in M. mollis essential oil during the first 48 h. The adjacent undamaged leaves showed similar changes, suggesting a systemic response. Composition of volatiles released from damaged leaves was also altered, most noticeably by increasing pulegone and diminishing menthone emissions. Such herbivore-induced chemical changes in aromatic plants are economically relevant, since the quality of essential oils and volatile emissions are altered.     

Hydrocarbon degradation and bioemulsifier production by thermophilic Geobacillus pallidus strains

Geobacillus pallidus XS2 and XS3 were isolated from oil contaminated soil samples in Yumen oilfield, China, and were able to produce bioemulsifiers on different hydrocarbons. Biodegradation assays exhibited that approximately 70% of PAH (250 mg/L) or 85% of crude oil (500 mg/L) was removed by the thermophilic bacteria after 20 days. The bioemulsifiers of the two strains were isolated and obtained a productive yield of 4.24 ± 0.08 and 3.82 ± 0.11 g/L, respectively. GPC analysis revealed that the number-average molecular weights (M_n) of the two bioemulsifiers were 271,785 Da and 526,369 Da, with PDI values of 1.104 and 1.027, respectively. Chemical composition studies exhibited that the bioemulsifier XS2 consisted of carbohydrates (68.6%), lipids (22.7%) and proteins (8.7%) while the bioemulsifier XS3 was composed by carbohydrates (41.1%), lipids (47.6%) and proteins (11.3%). Emulsification assays approved the effectiveness of bioemulsifiers over a wide range of temperature, pH and salinity.     

Effect of biosurfactant and fertilizer on biodegradation of crude oil by marine isolates of Bacillus megaterium, Corynebacterium kutscheri and Pseudomonas aeruginosa

This study was conducted to investigate the effects of fertilizers and biosurfactants on biodegradation of crude oil by three marine bacterial isolates; Bacillus megaterium, Corynebacterium kutscheri and Pseudomonas aeruginosa. Five sets of experiments were carried out in shake flask and microcosm conditions with crude oil as follows: Set 1-only bacterial cells added (no fertilizer and biosurfactant), Set 2-with additional fertilizer only, Set 3-with additional biosurfactant only, Set 4-with added biosurfactant + fertilizer, Set 5-with no bacterial cells added (control), all the above experimental sets were incubated for 168 h. The biosurfactant + fertilizer added Set 4, resulted in maximum crude oil degradation within shake flask and microcosm conditions. Among the three bacterial isolates, P. aeruginosa and biosurfactant produced by this strain resulted in maximum crude oil degradation compared to the other two bacterial strains investigated. Interestingly, when biosurfactant and bacterial cells were used (Set 3), significant oil biodegradation activity occurred and the difference between this treatment and that in Set 4 with added fertilizer + biosurfactant were only 4-5% higher degradation level in shake flask and 3.2-7% in microcosm experiments for all three bacterial strains used. It is concluded that, biosurfactants alone capable of promoting biodegradation to a large extent without added fertilizers, which will reduce the cost of bioremediation process and minimizes the dilution or wash away problems encountered when water soluble fertilizers used during bioremediation of aquatic environments.