Comparative study between three carbonaceous nanoblades and nanodarts for antimicrobial applications

The design of nanostructured materials occupies a privileged position in the development and management of affordable and effective technology in the antibacterial sector. Here, we discuss the antimicrobial properties of three carbonaceous nanoblades and nanodarts materials of graphene oxide (GO), reduced graphene oxide (RGO), and single-wall carbon nanotubes (SWCNTs) that have a mechano-bactericidal effect, and the ability to piercing or slicing bacterial membranes. To demonstrate the significance of size, morphology and composition on the antibacterial activity mechanism, the designed nanomaterials have been characterized. The minimum inhibitory concentration (MIC), standard agar well diffusion, and transmission electron microscopy were utilized to evaluate the antibacterial activity of GO, RGO, and SWCNTs. Based on the evidence obtained, the three carbonaceous materials exhibit activity against all microbial strains tested by completely encapsulating bacterial cells and causing morphological disruption by degrading the microbial cell membrane in the order of RGO > GO > SWCNTs. Because of the external cell wall structure and outer membrane proteins, the synthesized carbonaceous nanomaterials exhibited higher antibacterial activity against Gram-positive bacterial strains than Gram-negative and fungal microorganisms. RGO had the lowest MIC values (0.062, 0.125, and 0.25 mg/mL against B. subtilis, S. aureus, and E. coli, respectively), as well as minimum fungal concentrations (0.5 mg/mL for both A. fumigatus and C. albicans). At 12 hr, the cell viability values against tested microbial strains were completely suppressed. Cell lysis and death occurred as a result of severe membrane damage caused by microorganisms perched on RGO nanoblades. Our work gives an insight into the design of effective graphene-based antimicrobial materials for water treatment and remediation.

Effect of three dormant oils on schistosomiasis and fascioliasis vector snails and its relation with some non-target snails

Three oils were tested for their molluscicidal activity, Caple-2, Kemasol and Super-max. Super-max had the strongest toxic effect on B. alexandrina and other snail species. Its LC50 was 0.53 ppm, meanwhile LC50 of Kemasol 3.2 ppm and 4.21 ppm for Caple 2. The LC50 & LC90 of the oils were lower in Lymneae natalensis as compared to B. alexandrina. The LC50 & LC90 of the oils against non-target snails (Physa acuta, Helisoma duryi, Planorbis planorbis and Melanoides tuberculata) were higher as compared to B. alexandrina. Hatchability of snails' eggs exposed to Super-max (3.0 & 5.0 ppm) was stopped completely and l.0 ppm showed the lower percent of egg hatchability 22.7 %. Caple 2 and Kemasol did not affect eggs hatchability. Supermax had the strongest harmful effect on both miracidia and cercariae of S. mansoni. 100% mortality values were obtained for both larval stages after 8 & 9 minutes respectively when maintained at LC50. 100% mortality of miracidia occurred after 35 & 155 minutes when maintained at LC50 of Kemasol & Caple 2 respectively. The infection rate of B. alexandrina with S. mansoni miracidia was greatly reduced by the sublethal concentrations of the oils. The reduction of infection rate was higher in snails treated with Supermax (42.9%). A highly significant reduction of total cercarial production per snail was in the experimental groups as compared with controls. The prepatent period of treated snails was prolonged compared to control. Moreover, Total protein content and enzyme activities of snails treated with LC10 of oils showed a significant reduction as compared with control in haemolymyph. There was an increase of protein contents in the tissue. AlkP enzyme activity was slightly increased in haemolymph of experimental groups than controls and was significantly higher in the tissues as compared to control. ALT enzyme activity in haemolymph of experimental groups was higher than control, but lower in tissue. AST enzyme activity was higher in haemolymph and tissue of experimental groups than controls. The SDS-PAGE pattern of tissue soluble proteins extracted from treated B. alexandrina and controls showed different oils effects on the synthesis of protein within snails yielded a complex pattern of polypeptides ranging in molecular weight between 13.775 to 156.7 kDa. Many bands were present in treated snails. At least, one band was detected for snails treated with each of the oils and not in controls. The difference in the similarity indices between treatment and control; for Kemasol was 0.86 & 0.64, for Caple 2 was 0.61 & 0.55 and for Supermax was 0.64 & 0.86. LC25 of Supermax did not cause any mortality to Daphnia after 6 hr. But, LC50 & LC90 caused lower mortality after 6 hr. Kemasol caused 100% mortality after 4 hr at LC50 and 2 hr in LC90. Caple 2 caused 50% mortality of Daphnia after 5 hr at LC25 &100% mortality after 30 minutes in LC50 & LC90.

Semi field trials to control Biomphalaria alexandrina by different modes of exposure to certain plant and chemical molluscicides

Semi-field trials were carried out in Snail Research Station under simulated natural conditions to evaluate different modes of exposure to Anagallis arvensis and Calendula micrantha as plant molluscicides and bayluscide and copper sulphate as chemical molluscicides. Firstly, B. alexandrina were exposed to the tested molluscicides alone and in addition to two densities of aquatic plants. No apparent effect of aquatic plants on the activity of both plant and chemical molluscicides, this may be due that the two densities of the aquatic plants used were insufficient to interfere with the molluscicides action. Secondly, snails were pre-exposed to three sub-lethal concentrations of the plant molluscicides for 24h then to three concentrations of the chemical molluscicides and vice versa. The results indicate that the pre-exposure increases the snail mortality significantly in all treatments of bayluscide and A. arvensis (except in the highest concentration when the snails firstly exposed to bayluscide then to A. arvensis, where the two compared treatment showed 100%) and in all treatments of bayluscide and C. micrantha. Also, in one treatment of copper sulphate and A. arvensis (in the highest concentration when the snails firstly exposed to A. arvensis then to copper sulphate) and in three treatments of copper sulphate and C. micrantha, (in least and moderate concentrations when snails firstly exposed to C. micrantha then to copper sulphate and in the highest concentration when snails firstly exposed to copper sulphate then to C. micrantha). Thirdly, snails were exposed to mixtures of six different ratios of bayluscide and each of A. arvensis and C. micrantha. The results indicated that the snail mortality increased significantly only in the first treatment of bayluscide and A. arvensis mixtures and in treatment number 6 of bayluscide and C. micrantha.

Synthesis and evaluation of molluscicidal and larvicidal activities of some novel enaminones derived from 4-hydroxyquinolinones: part IX

A series of 10 3-(hetarylaminomethylene)quinolinediones, 12 3-(substituted aminopropenoyl)-4-hydroxyquinolinones, and 10 3-(substituted aminomethylene-5-oxo-pyrazolinyl)-4-hydroxyquinolinones were synthesized as novel enaminones derived from 3-(un)substituted 4-hydroxyquinolin-2(1H)-ones in 72-94% yields and assayed for their molluscicidal activities against Biomphalaria alexandrina and Lymnaea natalensis snails. Some of the tested enaminones presented high molluscicidal activities (LC(50)20ppm). The new compounds showed more potency against hatchability of B. alexandrina egg masses, the infection rate and prepatent period of the snails. In addition, these derivatives revealed potential larvicidal effects (100% mortality) on both miracidia and cercariae of Schistosoma mansoni at reduced exposure time. The selected active derivatives were examined against Daphnia magna and their nontoxic effect at all sublethal, lethal, and higher concentrations suggests that these compounds can play an important role as molluscicides and larvicides with environmental safe properties.

Difference in the susceptibility to certain molluscicides and Schistosoma mansoni infection of three forms Egyptian Biomphalaria glabrata

The first generation of 3 morphologically different forms of B. glabrata collected from Giza were compared for LC50 values susceptibility to bayluscide and copper sulphate (chemical molluscicides) and Anagallis arvensis and Calendula micrantha (plant molluscicides) and to Schistosoma mansoni infection. Form (2) as juvenile and adult were less sensitive to C. micrantha and A. arvensis. Form (3) as juvenile and form (1) as adult were least sensitive to CuSO4. Approximately the same susceptibility to bayluscide was observed in the 3 forms either as juvenile or adult. The sublethal concentrations of the molluscicides on B. glabrata 3 forms showed no significant difference in the growth or survival rate in between. Form (2) was significantly higher in the egg lying capacity. The total protein concentration was not affected except in certain cases where the increase was primarily due to the increase in the globulin concentrations which indicate with the marked increase observed in the urea concentration and marked increase or inhibition in the activity of either AST or ALT that the digestive gland of the 3 forms of snails is seriously affected by molluscicides. The 3 forms of B. glabrata showed low susceptibility to infection with the local strain of S. mansoni.

Bioactivity of Anagallis arvensis and Calendula micrantha plants, treated with ammonium nitrate, superphosphate and potassium sulphate fertilizers, on Biomphalaria alexandrina

The survival rate of B. alexandrina snails maintained in aqueous solutions of the two tested plants (Calendula micrantha and Anagallis arvensis) decreased gradually with time until the 9th week and 10th week where the survival rate was zero in the high concentration of A. arvensis and C. micrantha, respectively, meanwhile, the survival rate of the control was 20%. Also, the two plants caused reduction in hatchability of snails egg masses. Thus, the percent of hatching in A. arvensis (82 ppm) was 46% and in C. micrantha was 72% compared with control (97.29%). Both plants reduced the infection rate of Biomphalaria alexandrina snails with Schistosoma mansoni miracidia to 41.17% and 61.9%, respectively, compared with control (90%). C. micrantha caused much higher reduction in snail infection rate than A. arvensis. The prepatent period was significantly prolonged in snails maintained at higher concentration of both plants. The cercarial output (expressed as mean number/snail) revealed that, A. arevensis caused a significant reduction in cercarial production than control. While, high concentration (120 ppm) of C. micrantha caused a significant elevation in the mean number of cercariae/snail. However, the total number of cercariae produced by all snails in each group showed a reverse relation with the tested concentrations in both plants.

Studies on the molluscicidal action of some isatin derivatives against Biomphalaria alexandrina in Egypt

Some compounds selected from the isatin derivatives and their metalleted products were used to study their molluscicidal effect on Biomphalaria alexandrina. The results indicated that some of these compounds showed good results and seem to be promising molluscicides.

Effect of UV-irradiation, gamma irradiation and praziquantel on infected Biomphalaria alexandrina snails

Schistosomiasis control represent the main target of many research programme allover the world. Effect of physical (UV- and gamma-irradiation) treatment as well as chemical (PZQ) treatment on infected laboratory bred Biomphalria alexandrina snails have been studied. Gamma irradiation and PZQ-treatment induced high rate of mortality than UV-irradiated and non-treated control snails. The cercarial production was severely reduced as a result of UV-, gamma-irradiation and PZQ-treatment. Pre-patent period was significantly increased in gamma-irradiated and PZQ-treated groups than UV-irradiated and control groups. Gamma irradiation and PZQ-treatment showed severe effects on hermaphrodite gland and cercariae. Trials of experimental infection in swiss albino mice revealed that low rate of infection (9.7% and 1.3%) was induced by cercarial shedding from UV-irradiated and PZQ-treated snails respectively. Whereas, cercarial production of gamma-irradiated snails failed to induce infection in swiss mice.

Effect of X-ray on the snails of schistosomiasis in Egypt

Biomphalaria alexandrina and Bulinus truncatus snails were exposed to sublethal doses 0.2, 3, 5, 10 and 20 rad of X-ray. The survival and reproductive rates of these snails were highly affected by these doses. The maximum survival periods of laboratory populations of Biomphalaria snails were less than those of field ones which means a high sensitivity of laboratory snails to X-ray. The reproductive capacity of irradiated Biomphalaria and Bulinus snails was highly suppressed and this will interrupt Schistosomiasis transmission. A deleterious effect of gametogenesis of irradiated Biomphalaria was histologically proved. After 3 weeks of snail irradiation with high dose (40 rad) the hermaphrodite gland became completely evacuated.