Home > Cloning and Expression of Cdna Encoding Bioactive Venom Proteins from the Mealbug Parasitoid Aenasius Arizonesis Girault =Aenasius Bambawalei Hayat Hymenoptera, Encyrtidae
Cloning and Expression of Cdna Encoding Bioactive Venom Proteins from the Mealbug Parasitoid Aenasius Arizonesis Girault =Aenasius Bambawalei Hayat Hymenoptera, Encyrtidae
The Endoparasitoid Aenasius bambawalei Hayat (Hymenoptera, Encyrtidae) has been synonymized with Aenasius arizonensis (Girault) (Hymenoptera, Encyrtidae) in 2014. It is a newly emerged parasitoid of mealybug Phenacoccus solenopsis Tinsley (Hemiptera, Pseudococcidae) and it has been found an efficient insect control tool. There is little information available on parasitoid origin factors responsible for modulation of mealybug physiology. Parasitoid’s venom contains biologically active proteins that have potential applications in pest management, some of them also have medicinal importance but venom components of A. arizonensis have not been studied yet. Venom glands tissues of A. tarizonensis were used for transcriptomic study and transcriptomic database was developed by using high throughput RNA sequencing approaches using Illumina Technology. The transcriptomic data of A. arizonensis venom glands was analysed by utilizing high throughput sequencing Illumina technology and de novo assemblies were constructed, containing 30,267,259 sequences reads which yielded 30,154,362 contigs and 8,507 unigenes which had significant BLAST homologies n the NR database. The database sequences showed homology to 2666 Nasonia vitripennis genes, 2065 Copidosoma floridanum genes, 1660 Ceratosolen solmsi genes, 1598 Trichogramma pretiosum genes and 1192 Cerapachys biroi genes. Further analysis was performed by selecting some genes encoding venom proteins which are potentially involved in the disruption of host immune system, developemental arrest and host paralysis. Sequenced mRNAs predicted to encode full length ORFs of Calreticulin, Arginine kinase and serine protease precursor proteins were identified, and tissue specific expression of these putative venom proteins was performed by RT-PCR which reveals that venom genes were not only exclusively expressed in venom tissues but also conserved in all carcasses of the parasitoid species. Application of crude venom and expressed proteins on cultured cell lines showed valuable results for understanding that there are paralytic factors in parasitoid venom which cause cell death. Whereas in functional analysis of microinjections, venom treated with heat and proteinase showed non-significant mortality which suggests that bioactive components of the crude venom were proteins which lost their biological activities upon heat treatments. Additionally, results also demonstrated that transcriptome de novo assembly allows useful venom gene expression analysis in species lacking genome sequence database which ultimately provide useful information for devising control tools for insect pest. This work also contributes to the understanding of the molecular and physiological bases of host parasitoid interaction in insects that may provide an unexplored resource for diverse biotechnological application and useful information for entomologists seeking to devise sustainable control strategies for cotton mealybug.
During the period of total containment during the Covid-19 pandemic; our department became the sole treatment center for all surgical emergencies. The influx of many patients made the task very difficult for the surgeon. This is a 3-month descriptive prospective study in the visceral surgery department at the Analankininina Toamasina University Hospital Center. Of the 81 patients hospitalized during the study, 32 patients were admitted for digestive surgery emergency, i.e. 39.50%. The mean age was 34.87 years with a sex ratio of 1.66, predominantly male. Abdominal pain occupied 43.75% of the reason for consultation, the most frequent pathologies were acute intestinal obstruction (18.75%) and acute appendicitis (18.75%). An exploratory laparotomy is performed on 40.62% of patients. Many patients were operated on for proctologic emergency (18.75%). The average length of hospitalization is 4.18 days. The visceral emergencies are present despite the presence of the Covid-19 pandemic and the activities of the health personnel are uninterrupted.
Although the yield potential of spring maize is much higher than autumn maize, high temperature at reproductive stage is one of the main problems in spring especially in late sown conditions. Early sowing of the crop seems an ideal solution to escape the crop from heat spell but low temperature causes poor emergence and seedling establishment. Under these temperature extremes, osmotic and oxidative stresses are major reasons of crop damage. Exogenous application of various physiological strategies like antioxidants, osmoprotectants and plant hormones may lessen the damage. Initially in first two experiments, three levels of ascorbic acid, salicylic acid and hydrogen peroxide (0, 20 and 40 mg L-1) were optimized as seed priming or foliar application strategies under net house condition using single maize hybrid (Hi Swan-9697). The optimization was done on the basis of emergence and seedling vigor in priming experiment, 20 mg L-1 was selected as an optimized level all these compounds as an effective priming strategy. Seed primed with AsA, SA and H2O2 resulted in faster emergence, better, more and uniform stands. Seed priming with AsA, SA and H2O2 improved seedling vigor by increasing leaf Chl, nutrient content and better defense system with stimulating activities of SOD, CAT and POD in seedling. Foliar application of AsA, SA and H2O2 improved seedling vigor by increasing chlorophyll, nutrient contents and improving antioxidant defense system. Both levels of solutions of foliarly applied AsA, SA and H2O2 are equally effective for improving seedling vigor so the lower level of (20 mg L-1) was selected. The field experiment was conducted to explore the role of AsA, SA and H2O2 as seed priming agent and foliar application at three sowing dates i.e early (1st February), optimum (22nd February) and late (15th March). Different priming treatment enhanced rapid emergence but both priming and foliar application strategies caused earlier tasselling, silking and physiological maturity at each sowing dates. Improving antioxidants and nutrient homeostasis enhanced chlorophyll which improved growth and development under early and late stress conditions. It is suggested that all physiological strategies increased grain yield associated with improvement in number of grain and size of grain at each sowing dates by improved antioxidants defense system and nutrient homeostasis which reduce oxidative damages and improving stress tolerance under late sown condition of spring maize.