Tahany H. Ayaad

Survey and molecular detection of Melissococcus plutonius, the causative agent of European Foulbrood in honeybees in Saudi Arabia

A large-scale field survey was conducted to screen major Saudi Arabian beekeeping locations for infection by Melissococcus plutonius. M. plutonius is one of the major bacterial pathogens of honeybee broods and is the causative agent of European Foulbrood disease (EFB). Larvae from samples suspected of infection were collected from different apiaries and homogenized in phosphate buffered saline (PBS). Bacteria were isolated on MYPGP agar medium. Two bacterial isolates, ksuMP7 and ksuMP9 (16S rRNA GenBank accession numbers, KX417565 and KX417566, respectively), were subjected to molecular identification using M. plutonius -specific primers, a BLAST sequence analysis revealed that the two isolates were M. plutonius with more than 98% sequence identity. The molecular detection of M. plutonius from honeybee is the first recorded incidence of this pathogen in Saudi Arabia. This study emphasizes the need for official authorities to take immediate steps toward treating and limiting the spread of this disease throughout the country.

Diagnosis and molecular detection of Paenibacillus larvae, the causative agent of American foulbrood in honey bees in Saudi Arabia

Apis mellifera jemenitica, the only indigenous honey bee race of Saudi Arabia, is well adapted to the harsh local environmental conditions. A large-scale feld survey was conducted to screen major Saudi Arabian beekeeping locations for infection by Paenibacillus larvae. Paenibacillus larvae is one of the major bacterial pathogens of honey bee broods and is the causative agent of American foulbrood disease. Larvae from samples suspected of infection were collected from different apiaries and homogenized in phosphate-buffered saline. Bacteria were isolated on MYPGP agar medium. Two bacterial isolates, ksuPL3 and ksuPL5 (16S rRNA GenBank accession numbers, KR780760 and KR780761, respectively), were subjected to molecular identifcation using P. larvae-specifc primers. A BLAST sequence analysis revealed that the two isolates were P. larvae with more than 98% sequence identity. This detection of P. larvae in the indigenous honey bee is the frst recorded incidence of this pathogen in Saudi Arabia. This study emphasizes the need for the relevant authorities to take immediate steps towards treating and limiting the spread of this disease throughout the country.

Isolation and Characterization of Midgut Lectin From Aedes aegypti (L.) (Diptera: Culicidae)

The present investigation deals with the isolation and characterization of a lectin from Aedes aegypti (Ae aegypti) female mid gut extract that agglutinates various mammalian red blood cells (RBCs) such as human three groups A, B, and O (RH+), mouse, rat, guinea-pig, sheep and goat erythrocytes. The highest activity of both crude and isolated mid gut lectins were detected against sheep RBCs. Using (NH4)2 SO4 fractionation, ion-exchange and mannose-CNBr-Sepharose 6B affinity chromatography techniques, Ae. aegypti midgut lectin (Aelec) was purified to homogeneity.Isoelectric focusing (IEF) and reducing SDS/PAGE revealed that the isolated mid gut lectin had isoelectric point (PI) of 5.90, and subunits approximate molecular weights of 35.50 and 27.35 KDa. The hemagglutination (HA) of lectins were Ca2+ - independent and heat-resistant. The sugar specificity of the purified Aelec was strongly inhibited by D (+)-mannose and raffinose, followed by D (+) glucose. N-acetyl-D-manosamine and N-acetyl-D-glucosamine were moderate inhibitors. None of the lectins were inhibited by the disaccharides such as galactose, lactose, trehalose (IC50 up to 200 mM or fetuin up to 1%) but the glycosubstances mucin and laminarin were strong inhibitors up to very low concentrations (0.030 - 0.003%).

The immune defence system of the cattle tick Boophilus annulatus (Say) (Acari: Ixodidae): I. Microscopical and ultrastructural characterization of hemocytes.

Abstract Hemocytes of field-collected semiengorged female cattle ticks, Boophilus annulatus (Say), were characterized on the basis of hemocyte types, morphological cell features and ultrastructural characteristics of cytoplasmic inclusions. A distinction was made ultrastructurally between the types of hemocytes according to the presence or absence of granular inclusions, the shape and size of the lysosomal compartment and rough endoplasmic reticulum. Four types of hemocytes were detected: plasmatocytes type I and II, granular hemocytes and prohemocyte-like cells.