Synthesis of Tungsten Oxide, Iron Oxide, and Copper-Doped Iron Oxide Nanocomposites and Evaluation of Their Mixing Effects with Cyromazine against Spodoptera littoralis (Boisduval).

Nanotechnology research is emerging as a cutting-edge technology, and nanocomposites have played a significant role in pest control. Therefore, the present study focuses on the synthesis of tungsten oxide (WO3), iron oxide (magnetic nanoparticle, MNP), and copper-doped iron oxide (MNP-Cu) nanocomposites and explores the different effects of their binary combinations with the insecticide cyromazine against Spodoptera littoralis. The synthesized nanoparticles were characterized by transmission electron microscopy, X-ray diffraction, Fourier-transform infrared spectroscopy, and Raman spectroscopy. None of the tested nanomaterials showed any toxicity against the different stages of S. littoralis. Larval and pupal durations increased with increasing cyromazine and nanomaterial concentrations. The longest larval and pupal durations were recorded under treatment with the mixture of cyromazine (100 mg/L) + MNP-Cu (500 mg/L); the survival periods were 23.5 and 15.6 days, compared with 10.8 and 7.7 days in the control, respectively. The percentages of pupation and adult emergence were negatively affected by all treatments. Among the 500 mg/L nanomaterial combinations, only cyromazine (25 mg/L) and WO3 (500 mg/L) resulted in adult emergence (at a rate of 27.3%). Some abnormalities in the S. littoralis stages were observed following treatment with the tested materials. The glutathione S-transferase and alpha-esterase enzyme activities in S. littoralis were significantly increased after treatment with cyromazine, followed by cyromazine/MNP-Cu combinations. The quantitative polymerase chain reaction (Q-PCR) data showed that all treated insects had a higher immune response than the control. Finally, mixes of nanocomposites and cyromazine may be suggested as viable alternatives for S. littoralis management.

Composition and Diversity of the Culturable Endophytic Community of Six Stress-Tolerant Dessert Plants Grown in Stressful Soil in a Hot Dry Desert Region.

Saudi Arabia is part of a hot dry desert region and is characterized by stressful conditions. The main goal of this research was to identify endophytic fungal (EF) community composition, diversity and abundance in relation to their plant hosts and soil stress. The above-ground parts of six wild plants (Haloxylon salicornicum, Salsola kali, Heliotropium bacciferum, Erica verticillata, Salsola imbricata and Bienertia sinuspersici) were sampled, surface-sterilized and cut into small pieces, which were cultured and incubated for 4-6 weeks. Isolates were grouped and identified by using both morphological and ITS rDNA molecular data. The diversity and community structure of plant-endophyte associations were studied. A total of 455 EF isolates were grouped into 25 different taxa; 21 of which were identified at the species level, 2 at genus level and 2 were unclassified fungi. Here, 95.65% of the identified genera were Ascomycota; of which 36.36, 31.81 and 31.81% were members of the classes Dothideomycetes, Eurotiomycetes and Sordariomycetes, respectively. S. imbricata showed the highest isolation rate and colonization frequency (CF%) of EF when compared to other plant species. Additionally, S. imbricata demonstrated the highest species richness and species diversity of the EF community predominated by the genus Fusarium. Conclusively, the core culturable EF genera of six wild plants were identified (unculturable taxa were not identified in this study). The composition of the EF community was revealed to have a strong correlation to both the electrical conductivity and pH of the soil and a moderate correlation to both the host species and the host family. The abundance and diversity of EF communities of the six plants were environment-dependent.

Effect of extreme temperature changes on phenolic, flavonoid contents and antioxidant activity of tomato seedlings (Solanum lycopersicum L.).

BACKGROUND: Climatic changes are the most important abiotic factor affecting plant growth, crop quality and nutritional value. Plants exposed to thermal stress respond by accumulation of secondary metabolites/molecules (SMs). Tomato (Solanum lycopersicum) is a cosmopolitan crop, eaten by most of the world's people because it is highly nutritious plant. It is cultivated in more than 16 thousand hectares in Saudi Arabia and thus is influenced by extreme climatic changes. OBJECTIVE: In the current study, the phytochemical effect of thermal stress was investigated in seedlings of S. lycopersicum. Such information will be very helpful in developing more tolerant tomato cultivars in a climate change scenario. METHODS: Seedlings of S. lycopersicum were subjected to heat shock; HS1 and HS2 (45 and 50 °C) and cold shock; CS (4 °C) in comparison to control; Con (25 °C). Phenolic compounds, flavonoids, total phenolic content (TPC), total flavonoid content (TFC) and antioxidant activity were estimated under the four temperature treatments. RESULTS: Using 23 standards (17 phenolic and six flavonoids), HPLC resulted in the estimation of 16, 20, 15 and 18 compounds for Con, CS, HS1 and HS2, respectively. Differences in the amounts of total phenolics, and total flavonoids were strongly correlated to thermal stress. CS plants exhibited the highest number of signals and the highest absolute quantities of total phenolics, flavonoids and sum of both. The major peaks of phenolics were (Chlorogenic acid, Resvertol), (Vanillic acid, Benzoic acid, Quinol), (Vanillic acid, Benzoic acid) and (Vanillic acid, Benzoic acid) for Con, CS, HS1 and HS2, respectively. The major peaks of flavonoids were (Quercetin, Myricetin), (Quercetin, Rutin), (Quercetin, Rutin, Catechin) and (Quercetin) for Con, CS, HS1 and HS2, respectively. CS plants contain the highest amounts of Benzoic acid (8010.37 mg/kg FW) and Quercetin (2319.48 mg/kg FW). The highest TPC (131 mg GAE/100 g FW) and TFC (61 mg QE/100 g FW) were determined in the case of CS plants. In terms of IC50s, the CS plants showed the highest antioxidant activities (lowest values) in both of DPPH (467.73 µM TE/100 g FW) and ABTS (8.97 µM TE/100 g FW) assays. CONCLUSIONS: Our findings supported that the complexity and quantity of phenolics and flavonoids in tomato's extract are strongly related to thermal stress. Additionally, the CS plants demonstrated more desirable phytochemical profile over the other treatments. CS plants exhibited higher number, absolute amounts of SMs, higher TPC and TFC than those of Con, HS1 and HS2 plants. Additionally, CS plants showed higher antioxidant activity than that of both HS1 and HS2 plants. Such results are very useful in justifying mechanism of tolerance in tomato plant to thermal stress in the context of climate change. Additional research has turned on to reveal molecular response of tomato to such thermal stress.

LABORATORY STUDIES ON THE POSSIBILITY OF CULEX QUINQUEFASCIATUS TO HARBOR HEPATOZOON SP. INFECTING CERASTES CERASTES CERASTES VIPER IN EGYPT.

A successful experimental infection of Culex quinquefasciatus with Hepatozoon sp. infecting Cerastes cerastes cerastes viper was carried out under laboratory conditions of 24 +/- 3 degrees C and 60-70% R. H. The period monitored for complete sporogonic cycle was 21 days. The effect of high parasitimic blood meal was nonsignificant (P>0.05) on preoviposition period and hatchability. Meanwhile a highly significant reduction was observed in oviposition rate, number of deposited eggs, number of hatched larvae and longevity (P<0.01). On the contrary moderate infection with Hepatozoon revealed a great significant increase in fecundity (P<0.01) and a nonsignificant decrease in longevity (P>0.05)

Characterization of multisugar-binding C-type lectin (SpliLec) from a bacterial-challenged cotton leafworm, Spodoptera littoralis.

BACKGROUND: Various proteins that display carbohydrate-binding activity in a Ca(2+)-dependent manner are classified into the C-type lectin family. They have one or two C-type carbohydrate-recognition domains (CRDs) composed of 110-130 amino acid residues in common. C-type lectins mediate cell adhesion, non-self recognition, and immuno-protection processes in immune responses and thus play significant roles in clearance of invaders, either as cell surface receptors for microbial carbohydrates or as soluble proteins existing in tissue fluids. The lectin of Spodoptera littoralis is still uncharacterized. METHODOLOGY: A single orf encoding a deduced polypeptide consisting of an 18-residue signal peptide and a 291-residue mature peptide, termed SpliLec, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using RACE-PCR. Sequence analyses of the data revealed that SpliLec consists of two CRDs. Short-form CRD(1) and long-form CRD(2) are stabilized by two and three highly conserved disulfide bonds, respectively. SpliLec shares homology with some dipteran lectins suggesting possible common ancestor. The purified SpliLec exhibited a 140-kDa molecular mass with a subunit molecular mass of 35 kDa. The hemagglutination assays of the SpliLec confirmed a thermally stable, multisugar-binding C-type lectin that binds different erythrocytes. The purified SpliLec agglutinated microorganisms and exhibited comparable antimicrobial activity against gram (+) and gram (-) bacteria too. CONCLUSIONS: Our results suggested an important role of the SpliLec gene in cell adhesion and non-self recognition. It may cooperate with other AMPs in clearance of invaders of Spodoptera littoralis.

Identification, phylogenetic analysis and expression profile of an anionic insect defensin gene, with antibacterial activity, from bacterial-challenged cotton leafworm, Spodoptera littoralis.

BACKGROUND: Defensins are a well known family of cationic antibacterial peptides (AMPs) isolated from fungi, plants, insects, mussels, birds, and various mammals. They are predominantly active against gram (+) bacteria, and a few of them are also active against gram (-) bacteria and fungi. All insect defensins belonging to the invertebrate class have a consensus motif, C-X5₋16-C-X3-C-X9₋10-C-X4₋7-CX1-C. Only seven AMPs have already been found in different lepidopteran species. No report was published on the isolation of defensin from the Egyptian cotton leafworm, Spodoptera littoralis. RESULTS: An anionic defensin, termed SpliDef, was isolated from the haemolymph of the cotton leafworm, S. littoralis, after bacterial challenge using differential display technique. Based on sequence analyses of the data, specific primers for full length and mature peptide of defensin were designed and successfully amplified 471 and 150 bp amplicons. The integration of the results revealed that the 471 bp-PCR product has one open reading frame (orf) of 303 bp long, including both start codon (AUG) and stop codon (UGA). The deduced peptide consists of a 23-residues signal peptide, a 27-residues propeptide and a 50-residues mature peptide with the conserved six-cysteine motif of insect defensins. Both haemolymph and expressed protein exhibited antibacterial activities comparable to positive control. The RT-qPCR indicated that it was more than 41-folds up-regulated at 48 h p.i. CONCLUSION: Our results highlight an important immune role of the defensin gene in Spodoptera littoralis by cooperating with other AMPs to control bacterial infection.

Role of Culex and Anopheles mosquito species as potential vectors of rift valley fever virus in Sudan outbreak, 2007.

BACKGROUND: Rift Valley fever (RVF) is an acute febrile arthropod-borne viral disease of man and animals caused by a member of the Phlebovirus genus, one of the five genera in the family Bunyaviridae. RVF virus (RVFV) is transmitted between animals and human by mosquitoes, particularly those belonging to the Culex, Anopheles and Aedes genera. METHODS: Experiments were designed during RVF outbreak, 2007 in Sudan to provide an answer about many raised questions about the estimated role of vector in RVFV epidemiology. During this study, adult and immature mosquito species were collected from Khartoum and White Nile states, identified and species abundance was calculated. All samples were frozen individually for further virus detection. Total RNA was extracted from individual insects and RVF virus was detected from Culex, Anopheles and Aedes species using RT-PCR. In addition, data were collected about human cases up to November 24th, 2007 to asses the situation of the disease in affected states. Furthermore, a historical background of the RVF outbreaks was discussed in relation to global climatic anomalies and incriminated vector species. RESULTS: A total of 978 mosquitoes, belonging to 3 genera and 7 species, were collected during Sudan outbreak, 2007. Anopheles gambiae arabiensis was the most frequent species (80.7%) in White Nile state. Meanwhile, Cx. pipiens complex was the most abundant species (91.2%) in Khartoum state. RT-PCR was used and successfully amplified 551 bp within the M segment of the tripartite negative-sense single stranded RNA genome of RVFV. The virus was detected in female, male and larval stages of Culex and Anopheles species. The most affected human age interval was 15-29 years old followed by > or = 45 years old, 30-44 years old, and then 5-14 years old. Regarding to the profession, housewives followed by farmers, students, shepherd, workers and the free were more vulnerable to the infection. Furthermore, connection between human and entomological studies results in important human case-vulnerability relatedness findings. CONCLUSION: Model performance, integrated with epidemiologic and environmental surveillance systems should be assessed systematically for RVF and other mosquito-borne diseases using historical epidemiologic and satellite monitoring data. Case management related interventions; health education and vector control efforts are extremely effective in preparedness for viral hemorrhagic fever and other seasonal outbreaks.

Experimental transmission of Hepatozoon gracilis (Wenyon, 1909) com. nov., in its natural host the bean skink lizard (Mabuya quinquetaeniata quinquetaeniata) and vector Culex (C.) pipiens (Diptera: Culicidae).

The bean skink lizard Mabuya quinquetaeniata quinquetaeniata (Family: Scincidae) collected from Abu-Rawash, Giza was infected with the protozoon Hepatozoon gracilis. The mean percent of infection rate all over the year was 12.57% with the highest peak was in October (33%), meanwhile the lowest infection rate was detected in June (2.1%) and no infection was detected in February. Microscopical examination of experimentally infected Culex (C.) pipiens L smears revealed the presence of gamogony and sporogony stages of H. gracilis in their haemoceal. Cx. pipiens was capable to transmit H. gracilis to non-infected M. q. quinquetaeniata under laboratory conditions (21 +/- 1 & 60-70% R.H) after a prepatent period of 32 +/- 1 days from the infective bite. Various developmental schizogony stages were detected both in the lung endothelial cells and liver parenchymal cells. Developmental stages of H. gracilis in both vector or vertebrate host were described. Cx. pipiens was unable to transmit H. gracilis to snake, Psammophis schokari present in the same area of the bean skink lizard.

Influence of amphibian and reptile on the feeding preference, longevity and reproductive capacity of Egyptian Culex (Culex) pipiens Linneaus (Diptera-Culicidae).

Using Bufo regularis and ten reptile species as hosts for Culex pipiens under laboratory conditions revealed a great effect on feeding preference as a significant long feeding periods together with a significant reduction in the blood meal ratios were recorded. Female mosquitoes offered the experimental animals showed a short life span with different significant levels. A recognizable reduction in the reproductive fitness of Cx. pipiens females was recorded. Delayed oviposition and low ICI values was obtained. The percentage of egg hatching was not affected by the experimental animals.

Laboratory studies on the possibility of Culex (Culex) pipiens l. to harbour and transmit Hepatozoon matruhensis to the Egyptian snake Psammophis schokari.

A successful experimental infection of Psammophis schokari snake with Hepatozoon matruhensis through Culex (Culex) pipiens bites was carried out under laboratory condition of 20 +/- 1 degrees C and 60-70 % R.H. The period monitored for gametocyte maturation ranged from 38 to 42 days while the recorded prepatent period ranged from 28 to 35 days. The effect of infection was nonsignificant on longevity, incubation period and percenttage of egg hatching (P>0.05). Meanwhile a significant increase (P<0.05) in the preoviposition period together with a significant reduction (P<0.001) in the number of eggs deposited of infected females were recorded.

The effects of laboratory Hepatozoon gracilis infection on the fecundity, mortality and longevity of Culex (Culex) pipiens Linneaus (Diptera: Culicidae) in Egypt.

Laboratory observations on the effect of Hepatozoon gracilis on the egg production of the mosquito Cx. (Cx.) pipiens Linneaus under laboratory conditions revealed that H. gracilis infected mosquitoes produced significantly fewer eggs than uninfected ones. The egg production decreased as parasite burdens increased. Reduction in blood meal size in infected females did not reduce fecundity. No size differences was detected between oocyst-infected and uninfected females although sporozoite positive females were significantly large. Preoviposition period was affected significantly, while incubation period and percentage of egg hatching showed no significant changes. The longevity of female infected mosquitoes decreased insignificantly than in uninfected ones.