Mohammed S. Al-Khalifa

Human breast carcinoma cells are induced to apoptosis by samsum ant venom through an IGF-1-dependant pathway, PI3K/AKT and ERK signaling

In the present study we evaluated the anti-tumor potential of samsum ant venom (SAV) from Pachycondyla sennaarensis on the human breast carcinoma cell line MCF-7. We found that SAV induced growth arrest of MCF-7 cells without affecting the viability of MCF-10 (non-tumorigenic normal breast epithelial cells) and normal PBMCs. We then analyzed its impact on IGF-1-mediated MCF-7 cell proliferation and its effect on the underlying IGF-1 signaling pathways. Using flow cytometry analysis, we showed that the percentage of apoptotic cells was fourfold higher in SAV-treated cells as compared to untreated cells. More importantly, treatment with SAV induced a marked reduction in actin polymerization and a subsequent marked reduction in IGF-1-mediated cell proliferation. In addition to growth-inhibitory and pro-apoptotic effects, significant reductions were also observed in the phosphorylation of AKT and ERK, but not p38MAPK, in SAV-treated cells as compared to untreated cells. Our data reveal unique anti-tumor effects of samsum ant venom.

Blood parasites of livestock in certain Regions in Saudi Arabia.

Blood samples from camels, sheep, goats and cattle from six Regions in Saudi Arabia were examined for blood parasites. Asir Region camels were disinfected while those of the Eastern, Jazan, Northern Frontiers, Riyadh and Tabouk Regions were infected with Trypanosoma evansi (5-40%), those of Riyadh and the Eastern Regions were infected with Dipetalonema evansi (1-6%) and those of the Eastern, Jazan and Riyadh Regions were infected with Eperythrozoon species (8-20%). Sheep and goats of all tested regions were infected with Theilaria hirci (4-20% and 6-14%, respectively), Theilaria ovis (5-19% and 6-24%, respectively) and Eperthrozoon ovis (2-9% and 2-8%, respectively). Sheep of the Eastern and Northern Frontiers Regions were also infected with Anaplasma ovis (2%) and also those of the Eastern Region were infected with Babesia motasi (4%) as well. Cattle of Asir and Eastern Regions were infected with Anaplasma marginale (1-3.4%) and those of the Eastern, Jazan and Riyadh Regions were infected with Theileria annulata (11.3-25%) and Eperthrozoon wenyoni (1-4%). Moreover, Jazan cattle were infected with Babesia bigemina (6%) and a benign Theileria species (27%). Some of these parasites are recorded in new localities indicating that they are spreading in the country. Also, this is the first report in Saudi Arabia of D. evansi in camels, A. ovis and B. motasi in sheep and A. marginale and B. bigemina in cattle. These parasites may be introduced into the country with infected livestock infested with the vectors of these parasites. The suspected vectors of the detected parasites in Saudi Arabia is discussed. Follow up surveys of blood parasites are recommended to assess their distribution and infection rates in the livestock of all Regions of Saudi Arabia, to make plans for control measures against their vectors.

A novel intramandibular gland in the ant Brachyponera sennaarensis

One of the diagnostic characters of the ponerine ant genus Brachyponera is the presence of a mandibular pit near the insertion of the mandible. This paper describes the morphology and ultrastructure of a novel intramandibular gland in B. sennaarensis, that is associated with this pit. The gland appears as a conspicuous epithelium that lines the invaginated cuticle of the pit, and that extends distally into the upper and lower outer wall of the mandible. This novel ‘mandibular pit gland’ occurs in both workers and queens, but is absent in males. At the ultrastructural level, the cytoplasm of the cylindrical secretory cells is dominated by a well-developed smooth endoplasmic reticulum. Apical microvilli and clear transcuticular channels allow secretion to reach the mandibular surface. Although the function of this novel gland is not yet known, the cytoplasmic organization is in line with the production of a pheromonal secretion.

Samsum ant, Brachyponera sennaarensis (Formicidae: Ponerinae): Distribution and abundance in Saudi Arabia

Invasive species are capable of causing considerable damage to natural ecosystems, agriculture and economies throughout the World. Samsum ant, Brachyponera (Pachycondyla) sennaarensis has been a reason for medical implication and social nuisance through its poisonous and severely painful sting causing anaphylactic shock in many cases. We surveyed for the presence of the samsum ant in various provinces of Saudi Arabia. B. sennaarensis was the abundant Ponerinae species in human settlements. In the Eastern provinces, however, few samples were collected, and none were found in the Northern and Western provinces. Infestations of B. sennaarensis were particularly severe in the spring and summer seasons, when the ants make nests in moist areas and in cracks in cemented structures, whereas the extent of infestation reduced in winter seasons.

Pretarsus structure in relation to climbing ability in the ants Brachyponera sennaarensis and Daceton armigerum

We studied the external and internal pretarsus structure of the ants Brachyponera sennaarensis and Daceton armigerum in relation to their very different climbing ability. B. sennaarensis is a ground-dwelling species that is not able to climb vertical smooth walls. They have a pair of straight pretarsal claws with an average claw tip angle of 56 degrees, while the ventral tarsal surface lacks fine hairs that touch the substrate. They have no adhesive pad on the vestigial arolium, while the arolium gland is very small. D. armigerum, on the other hand, is an arboreal and thus well-climbing species with a very strong grip on the substrate. Their pretarsal claws are very hooked, with a claw tip angle around 75 degrees. They have dense arrays of fine hairs on the ventral tarsal surface, a well-developed arolium and arolium gland. These clearly different morphological characteristics are in line with the opposite climbing performance of both species.

Classical Practices and Pheromones in Biopesticides

Application of biopesticides is a globally rising phenomena on yearly basis, and the use of traditional insecticides is on the decline. North America uses the largest percentage of the biopesticide market share at 44 %, followed by the Europe with 20 %, each South and Latin American countries with 10 %, and about 6 % in Asia and India. However biopesticide growth is projected at 10 % annually; it is highly variable among the regions constrained by factors such as regulatory hurdles, public and political attitudes, and limitations for market expansion. Microbial biopesticides have been registered globally for 35 years, but the number of registrations for commercial restricted industry and domestic uses has significantly increased over the past 10 years.